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8sa1-gcc/gcc/ada/sem_res.adb
Arnaud Charlet b7e68e7de0 [Ada] Crash on if expression inside declare expression 
gcc/ada/

	* sem_res.adb (Resolve_Declare_Expression): Need to establish a
	transient scope in case Expression (N) requires actions to be
	wrapped.  Code cleanup.
	* exp_ch7.adb, exp_ch11.adb: Code cleanup.
2020-12-17 05:49:23 -05:00

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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M _ R E S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2020, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Aspects; use Aspects;
with Atree; use Atree;
with Checks; use Checks;
with Debug; use Debug;
with Debug_A; use Debug_A;
with Einfo; use Einfo;
with Errout; use Errout;
with Expander; use Expander;
with Exp_Ch6; use Exp_Ch6;
with Exp_Ch7; use Exp_Ch7;
with Exp_Disp; use Exp_Disp;
with Exp_Tss; use Exp_Tss;
with Exp_Util; use Exp_Util;
with Freeze; use Freeze;
with Ghost; use Ghost;
with Inline; use Inline;
with Itypes; use Itypes;
with Lib; use Lib;
with Lib.Xref; use Lib.Xref;
with Namet; use Namet;
with Nmake; use Nmake;
with Nlists; use Nlists;
with Opt; use Opt;
with Output; use Output;
with Par_SCO; use Par_SCO;
with Restrict; use Restrict;
with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Aggr; use Sem_Aggr;
with Sem_Attr; use Sem_Attr;
with Sem_Aux; use Sem_Aux;
with Sem_Cat; use Sem_Cat;
with Sem_Ch3; use Sem_Ch3;
with Sem_Ch4; use Sem_Ch4;
with Sem_Ch6; use Sem_Ch6;
with Sem_Ch8; use Sem_Ch8;
with Sem_Ch13; use Sem_Ch13;
with Sem_Dim; use Sem_Dim;
with Sem_Disp; use Sem_Disp;
with Sem_Dist; use Sem_Dist;
with Sem_Elab; use Sem_Elab;
with Sem_Elim; use Sem_Elim;
with Sem_Eval; use Sem_Eval;
with Sem_Intr; use Sem_Intr;
with Sem_Mech; use Sem_Mech;
with Sem_Type; use Sem_Type;
with Sem_Util; use Sem_Util;
with Sem_Warn; use Sem_Warn;
with Sinfo; use Sinfo;
with Sinfo.CN; use Sinfo.CN;
with Snames; use Snames;
with Stand; use Stand;
with Stringt; use Stringt;
with Style; use Style;
with Targparm; use Targparm;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
with Urealp; use Urealp;
package body Sem_Res is
-----------------------
-- Local Subprograms --
-----------------------
-- Second pass (top-down) type checking and overload resolution procedures
-- Typ is the type required by context. These procedures propagate the
-- type information recursively to the descendants of N. If the node is not
-- overloaded, its Etype is established in the first pass. If overloaded,
-- the Resolve routines set the correct type. For arithmetic operators, the
-- Etype is the base type of the context.
-- Note that Resolve_Attribute is separated off in Sem_Attr
procedure Check_Discriminant_Use (N : Node_Id);
-- Enforce the restrictions on the use of discriminants when constraining
-- a component of a discriminated type (record or concurrent type).
procedure Check_For_Visible_Operator (N : Node_Id; T : Entity_Id);
-- Given a node for an operator associated with type T, check that the
-- operator is visible. Operators all of whose operands are universal must
-- be checked for visibility during resolution because their type is not
-- determinable based on their operands.
procedure Check_Fully_Declared_Prefix
(Typ : Entity_Id;
Pref : Node_Id);
-- Check that the type of the prefix of a dereference is not incomplete
function Check_Infinite_Recursion (Call : Node_Id) return Boolean;
-- Given a call node, Call, which is known to occur immediately within the
-- subprogram being called, determines whether it is a detectable case of
-- an infinite recursion, and if so, outputs appropriate messages. Returns
-- True if an infinite recursion is detected, and False otherwise.
procedure Check_No_Direct_Boolean_Operators (N : Node_Id);
-- N is the node for a logical operator. If the operator is predefined, and
-- the root type of the operands is Standard.Boolean, then a check is made
-- for restriction No_Direct_Boolean_Operators. This procedure also handles
-- the style check for Style_Check_Boolean_And_Or.
function Is_Atomic_Ref_With_Address (N : Node_Id) return Boolean;
-- N is either an indexed component or a selected component. This function
-- returns true if the prefix refers to an object that has an address
-- clause (the case in which we may want to issue a warning).
function Is_Definite_Access_Type (E : Entity_Id) return Boolean;
-- Determine whether E is an access type declared by an access declaration,
-- and not an (anonymous) allocator type.
function Is_Predefined_Op (Nam : Entity_Id) return Boolean;
-- Utility to check whether the entity for an operator is a predefined
-- operator, in which case the expression is left as an operator in the
-- tree (else it is rewritten into a call). An instance of an intrinsic
-- conversion operation may be given an operator name, but is not treated
-- like an operator. Note that an operator that is an imported back-end
-- builtin has convention Intrinsic, but is expected to be rewritten into
-- a call, so such an operator is not treated as predefined by this
-- predicate.
procedure Preanalyze_And_Resolve
(N : Node_Id;
T : Entity_Id;
With_Freezing : Boolean);
-- Subsidiary of public versions of Preanalyze_And_Resolve.
procedure Replace_Actual_Discriminants (N : Node_Id; Default : Node_Id);
-- If a default expression in entry call N depends on the discriminants
-- of the task, it must be replaced with a reference to the discriminant
-- of the task being called.
procedure Resolve_Op_Concat_Arg
(N : Node_Id;
Arg : Node_Id;
Typ : Entity_Id;
Is_Comp : Boolean);
-- Internal procedure for Resolve_Op_Concat to resolve one operand of
-- concatenation operator. The operand is either of the array type or of
-- the component type. If the operand is an aggregate, and the component
-- type is composite, this is ambiguous if component type has aggregates.
procedure Resolve_Op_Concat_First (N : Node_Id; Typ : Entity_Id);
-- Does the first part of the work of Resolve_Op_Concat
procedure Resolve_Op_Concat_Rest (N : Node_Id; Typ : Entity_Id);
-- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
-- has been resolved. See Resolve_Op_Concat for details.
procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Call (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Case_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Declare_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Expression_With_Actions (N : Node_Id; Typ : Entity_Id);
procedure Resolve_If_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Generalized_Indexing (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Null (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Raise_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Range (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id);
procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Target_Name (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Unchecked_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Unchecked_Type_Conversion (N : Node_Id; Typ : Entity_Id);
function Operator_Kind
(Op_Name : Name_Id;
Is_Binary : Boolean) return Node_Kind;
-- Utility to map the name of an operator into the corresponding Node. Used
-- by other node rewriting procedures.
procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id);
-- Resolve actuals of call, and add default expressions for missing ones.
-- N is the Node_Id for the subprogram call, and Nam is the entity of the
-- called subprogram.
procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id);
-- Called from Resolve_Call, when the prefix denotes an entry or element
-- of entry family. Actuals are resolved as for subprograms, and the node
-- is rebuilt as an entry call. Also called for protected operations. Typ
-- is the context type, which is used when the operation is a protected
-- function with no arguments, and the return value is indexed.
procedure Resolve_Implicit_Dereference (P : Node_Id);
-- Called when P is the prefix of an indexed component, or of a selected
-- component, or of a slice. If P is of an access type, we unconditionally
-- rewrite it as an explicit dereference. This ensures that the expander
-- and the code generator have a fully explicit tree to work with.
procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id);
-- A call to a user-defined intrinsic operator is rewritten as a call to
-- the corresponding predefined operator, with suitable conversions. Note
-- that this applies only for intrinsic operators that denote predefined
-- operators, not ones that are intrinsic imports of back-end builtins.
procedure Resolve_Intrinsic_Unary_Operator (N : Node_Id; Typ : Entity_Id);
-- Ditto, for arithmetic unary operators
procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id);
-- If an operator node resolves to a call to a user-defined operator,
-- rewrite the node as a function call.
procedure Make_Call_Into_Operator
(N : Node_Id;
Typ : Entity_Id;
Op_Id : Entity_Id);
-- Inverse transformation: if an operator is given in functional notation,
-- then after resolving the node, transform into an operator node, so that
-- operands are resolved properly. Recall that predefined operators do not
-- have a full signature and special resolution rules apply.
procedure Rewrite_Renamed_Operator
(N : Node_Id;
Op : Entity_Id;
Typ : Entity_Id);
-- An operator can rename another, e.g. in an instantiation. In that
-- case, the proper operator node must be constructed and resolved.
procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id);
-- The String_Literal_Subtype is built for all strings that are not
-- operands of a static concatenation operation. If the argument is not
-- a N_String_Literal node, then the call has no effect.
procedure Set_Slice_Subtype (N : Node_Id);
-- Build subtype of array type, with the range specified by the slice
procedure Simplify_Type_Conversion (N : Node_Id);
-- Called after N has been resolved and evaluated, but before range checks
-- have been applied. This rewrites the conversion into a simpler form.
function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id;
-- A universal_fixed expression in an universal context is unambiguous if
-- there is only one applicable fixed point type. Determining whether there
-- is only one requires a search over all visible entities, and happens
-- only in very pathological cases (see 6115-006).
-------------------------
-- Ambiguous_Character --
-------------------------
procedure Ambiguous_Character (C : Node_Id) is
E : Entity_Id;
begin
if Nkind (C) = N_Character_Literal then
Error_Msg_N ("ambiguous character literal", C);
-- First the ones in Standard
Error_Msg_N ("\\possible interpretation: Character!", C);
Error_Msg_N ("\\possible interpretation: Wide_Character!", C);
-- Include Wide_Wide_Character in Ada 2005 mode
if Ada_Version >= Ada_2005 then
Error_Msg_N ("\\possible interpretation: Wide_Wide_Character!", C);
end if;
-- Now any other types that match
E := Current_Entity (C);
while Present (E) loop
Error_Msg_NE ("\\possible interpretation:}!", C, Etype (E));
E := Homonym (E);
end loop;
end if;
end Ambiguous_Character;
-------------------------
-- Analyze_And_Resolve --
-------------------------
procedure Analyze_And_Resolve (N : Node_Id) is
begin
Analyze (N);
Resolve (N);
end Analyze_And_Resolve;
procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id) is
begin
Analyze (N);
Resolve (N, Typ);
end Analyze_And_Resolve;
-- Versions with check(s) suppressed
procedure Analyze_And_Resolve
(N : Node_Id;
Typ : Entity_Id;
Suppress : Check_Id)
is
Scop : constant Entity_Id := Current_Scope;
begin
if Suppress = All_Checks then
declare
Sva : constant Suppress_Array := Scope_Suppress.Suppress;
begin
Scope_Suppress.Suppress := (others => True);
Analyze_And_Resolve (N, Typ);
Scope_Suppress.Suppress := Sva;
end;
else
declare
Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
begin
Scope_Suppress.Suppress (Suppress) := True;
Analyze_And_Resolve (N, Typ);
Scope_Suppress.Suppress (Suppress) := Svg;
end;
end if;
if Current_Scope /= Scop
and then Scope_Is_Transient
then
-- This can only happen if a transient scope was created for an inner
-- expression, which will be removed upon completion of the analysis
-- of an enclosing construct. The transient scope must have the
-- suppress status of the enclosing environment, not of this Analyze
-- call.
Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress :=
Scope_Suppress;
end if;
end Analyze_And_Resolve;
procedure Analyze_And_Resolve
(N : Node_Id;
Suppress : Check_Id)
is
Scop : constant Entity_Id := Current_Scope;
begin
if Suppress = All_Checks then
declare
Sva : constant Suppress_Array := Scope_Suppress.Suppress;
begin
Scope_Suppress.Suppress := (others => True);
Analyze_And_Resolve (N);
Scope_Suppress.Suppress := Sva;
end;
else
declare
Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
begin
Scope_Suppress.Suppress (Suppress) := True;
Analyze_And_Resolve (N);
Scope_Suppress.Suppress (Suppress) := Svg;
end;
end if;
if Current_Scope /= Scop and then Scope_Is_Transient then
Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress :=
Scope_Suppress;
end if;
end Analyze_And_Resolve;
----------------------------
-- Check_Discriminant_Use --
----------------------------
procedure Check_Discriminant_Use (N : Node_Id) is
PN : constant Node_Id := Parent (N);
Disc : constant Entity_Id := Entity (N);
P : Node_Id;
D : Node_Id;
begin
-- Any use in a spec-expression is legal
if In_Spec_Expression then
null;
elsif Nkind (PN) = N_Range then
-- Discriminant cannot be used to constrain a scalar type
P := Parent (PN);
if Nkind (P) = N_Range_Constraint
and then Nkind (Parent (P)) = N_Subtype_Indication
and then Nkind (Parent (Parent (P))) = N_Component_Definition
then
Error_Msg_N ("discriminant cannot constrain scalar type", N);
elsif Nkind (P) = N_Index_Or_Discriminant_Constraint then
-- The following check catches the unusual case where a
-- discriminant appears within an index constraint that is part
-- of a larger expression within a constraint on a component,
-- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
-- check case of record components, and note that a similar check
-- should also apply in the case of discriminant constraints
-- below. ???
-- Note that the check for N_Subtype_Declaration below is to
-- detect the valid use of discriminants in the constraints of a
-- subtype declaration when this subtype declaration appears
-- inside the scope of a record type (which is syntactically
-- illegal, but which may be created as part of derived type
-- processing for records). See Sem_Ch3.Build_Derived_Record_Type
-- for more info.
if Ekind (Current_Scope) = E_Record_Type
and then Scope (Disc) = Current_Scope
and then not
(Nkind (Parent (P)) = N_Subtype_Indication
and then
Nkind (Parent (Parent (P))) in N_Component_Definition
| N_Subtype_Declaration
and then Paren_Count (N) = 0)
then
Error_Msg_N
("discriminant must appear alone in component constraint", N);
return;
end if;
-- Detect a common error:
-- type R (D : Positive := 100) is record
-- Name : String (1 .. D);
-- end record;
-- The default value causes an object of type R to be allocated
-- with room for Positive'Last characters. The RM does not mandate
-- the allocation of the maximum size, but that is what GNAT does
-- so we should warn the programmer that there is a problem.
Check_Large : declare
SI : Node_Id;
T : Entity_Id;
TB : Node_Id;
CB : Entity_Id;
function Large_Storage_Type (T : Entity_Id) return Boolean;
-- Return True if type T has a large enough range that any
-- array whose index type covered the whole range of the type
-- would likely raise Storage_Error.
------------------------
-- Large_Storage_Type --
------------------------
function Large_Storage_Type (T : Entity_Id) return Boolean is
begin
-- The type is considered large if its bounds are known at
-- compile time and if it requires at least as many bits as
-- a Positive to store the possible values.
return Compile_Time_Known_Value (Type_Low_Bound (T))
and then Compile_Time_Known_Value (Type_High_Bound (T))
and then
Minimum_Size (T, Biased => True) >=
RM_Size (Standard_Positive);
end Large_Storage_Type;
-- Start of processing for Check_Large
begin
-- Check that the Disc has a large range
if not Large_Storage_Type (Etype (Disc)) then
goto No_Danger;
end if;
-- If the enclosing type is limited, we allocate only the
-- default value, not the maximum, and there is no need for
-- a warning.
if Is_Limited_Type (Scope (Disc)) then
goto No_Danger;
end if;
-- Check that it is the high bound
if N /= High_Bound (PN)
or else No (Discriminant_Default_Value (Disc))
then
goto No_Danger;
end if;
-- Check the array allows a large range at this bound. First
-- find the array
SI := Parent (P);
if Nkind (SI) /= N_Subtype_Indication then
goto No_Danger;
end if;
T := Entity (Subtype_Mark (SI));
if not Is_Array_Type (T) then
goto No_Danger;
end if;
-- Next, find the dimension
TB := First_Index (T);
CB := First (Constraints (P));
while True
and then Present (TB)
and then Present (CB)
and then CB /= PN
loop
Next_Index (TB);
Next (CB);
end loop;
if CB /= PN then
goto No_Danger;
end if;
-- Now, check the dimension has a large range
if not Large_Storage_Type (Etype (TB)) then
goto No_Danger;
end if;
-- Warn about the danger
Error_Msg_N
("??creation of & object may raise Storage_Error!",
Scope (Disc));
<<No_Danger>>
null;
end Check_Large;
end if;
-- Legal case is in index or discriminant constraint
elsif Nkind (PN) in N_Index_Or_Discriminant_Constraint
| N_Discriminant_Association
then
if Paren_Count (N) > 0 then
Error_Msg_N
("discriminant in constraint must appear alone", N);
elsif Nkind (N) = N_Expanded_Name
and then Comes_From_Source (N)
then
Error_Msg_N
("discriminant must appear alone as a direct name", N);
end if;
return;
-- Otherwise, context is an expression. It should not be within (i.e. a
-- subexpression of) a constraint for a component.
else
D := PN;
P := Parent (PN);
while Nkind (P) not in
N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
loop
D := P;
P := Parent (P);
exit when No (P);
end loop;
-- If the discriminant is used in an expression that is a bound of a
-- scalar type, an Itype is created and the bounds are attached to
-- its range, not to the original subtype indication. Such use is of
-- course a double fault.
if (Nkind (P) = N_Subtype_Indication
and then Nkind (Parent (P)) in N_Component_Definition
| N_Derived_Type_Definition
and then D = Constraint (P))
-- The constraint itself may be given by a subtype indication,
-- rather than by a more common discrete range.
or else (Nkind (P) = N_Subtype_Indication
and then
Nkind (Parent (P)) = N_Index_Or_Discriminant_Constraint)
or else Nkind (P) = N_Entry_Declaration
or else Nkind (D) = N_Defining_Identifier
then
Error_Msg_N
("discriminant in constraint must appear alone", N);
end if;
end if;
end Check_Discriminant_Use;
--------------------------------
-- Check_For_Visible_Operator --
--------------------------------
procedure Check_For_Visible_Operator (N : Node_Id; T : Entity_Id) is
begin
if Is_Invisible_Operator (N, T) then
Error_Msg_NE -- CODEFIX
("operator for} is not directly visible!", N, First_Subtype (T));
Error_Msg_N -- CODEFIX
("use clause would make operation legal!", N);
end if;
end Check_For_Visible_Operator;
----------------------------------
-- Check_Fully_Declared_Prefix --
----------------------------------
procedure Check_Fully_Declared_Prefix
(Typ : Entity_Id;
Pref : Node_Id)
is
begin
-- Check that the designated type of the prefix of a dereference is
-- not an incomplete type. This cannot be done unconditionally, because
-- dereferences of private types are legal in default expressions. This
-- case is taken care of in Check_Fully_Declared, called below. There
-- are also 2005 cases where it is legal for the prefix to be unfrozen.
-- This consideration also applies to similar checks for allocators,
-- qualified expressions, and type conversions.
-- An additional exception concerns other per-object expressions that
-- are not directly related to component declarations, in particular
-- representation pragmas for tasks. These will be per-object
-- expressions if they depend on discriminants or some global entity.
-- If the task has access discriminants, the designated type may be
-- incomplete at the point the expression is resolved. This resolution
-- takes place within the body of the initialization procedure, where
-- the discriminant is replaced by its discriminal.
if Is_Entity_Name (Pref)
and then Ekind (Entity (Pref)) = E_In_Parameter
then
null;
-- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
-- are handled by Analyze_Access_Attribute, Analyze_Assignment,
-- Analyze_Object_Renaming, and Freeze_Entity.
elsif Ada_Version >= Ada_2005
and then Is_Entity_Name (Pref)
and then Is_Access_Type (Etype (Pref))
and then Ekind (Directly_Designated_Type (Etype (Pref))) =
E_Incomplete_Type
and then Is_Tagged_Type (Directly_Designated_Type (Etype (Pref)))
then
null;
else
Check_Fully_Declared (Typ, Parent (Pref));
end if;
end Check_Fully_Declared_Prefix;
------------------------------
-- Check_Infinite_Recursion --
------------------------------
function Check_Infinite_Recursion (Call : Node_Id) return Boolean is
function Enclosing_Declaration_Or_Statement (N : Node_Id) return Node_Id;
-- Return the nearest enclosing declaration or statement that houses
-- arbitrary node N.
function Invoked_With_Different_Arguments (N : Node_Id) return Boolean;
-- Determine whether call N invokes the related enclosing subprogram
-- with actuals that differ from the subprogram's formals.
function Is_Conditional_Statement (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N denotes a conditional construct
function Is_Control_Flow_Statement (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N denotes a control flow statement
-- or a construct that may contains such a statement.
function Is_Immediately_Within_Body (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N appears immediately within the
-- statements of an entry or subprogram body.
function Is_Raise_Idiom (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N appears immediately within the
-- body of an entry or subprogram, and is preceded by a single raise
-- statement.
function Is_Raise_Statement (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N denotes a raise statement
function Is_Sole_Statement (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N is the sole source statement in
-- the body of the enclosing subprogram.
function Preceded_By_Control_Flow_Statement (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N is preceded by a control flow
-- statement.
function Within_Conditional_Statement (N : Node_Id) return Boolean;
-- Determine whether arbitrary node N appears within a conditional
-- construct.
----------------------------------------
-- Enclosing_Declaration_Or_Statement --
----------------------------------------
function Enclosing_Declaration_Or_Statement
(N : Node_Id) return Node_Id
is
Par : Node_Id;
begin
Par := N;
while Present (Par) loop
if Is_Declaration (Par) or else Is_Statement (Par) then
return Par;
-- Prevent the search from going too far
elsif Is_Body_Or_Package_Declaration (Par) then
exit;
end if;
Par := Parent (Par);
end loop;
return N;
end Enclosing_Declaration_Or_Statement;
--------------------------------------
-- Invoked_With_Different_Arguments --
--------------------------------------
function Invoked_With_Different_Arguments (N : Node_Id) return Boolean is
Subp : constant Entity_Id := Entity (Name (N));
Actual : Node_Id;
Formal : Entity_Id;
begin
-- Determine whether the formals of the invoked subprogram are not
-- used as actuals in the call.
Actual := First_Actual (Call);
Formal := First_Formal (Subp);
while Present (Actual) and then Present (Formal) loop
-- The current actual does not match the current formal
if not (Is_Entity_Name (Actual)
and then Entity (Actual) = Formal)
then
return True;
end if;
Next_Actual (Actual);
Next_Formal (Formal);
end loop;
return False;
end Invoked_With_Different_Arguments;
------------------------------
-- Is_Conditional_Statement --
------------------------------
function Is_Conditional_Statement (N : Node_Id) return Boolean is
begin
return
Nkind (N) in N_And_Then
| N_Case_Expression
| N_Case_Statement
| N_If_Expression
| N_If_Statement
| N_Or_Else;
end Is_Conditional_Statement;
-------------------------------
-- Is_Control_Flow_Statement --
-------------------------------
function Is_Control_Flow_Statement (N : Node_Id) return Boolean is
begin
-- It is assumed that all statements may affect the control flow in
-- some way. A raise statement may be expanded into a non-statement
-- node.
return Is_Statement (N) or else Is_Raise_Statement (N);
end Is_Control_Flow_Statement;
--------------------------------
-- Is_Immediately_Within_Body --
--------------------------------
function Is_Immediately_Within_Body (N : Node_Id) return Boolean is
HSS : constant Node_Id := Parent (N);
begin
return
Nkind (HSS) = N_Handled_Sequence_Of_Statements
and then Nkind (Parent (HSS)) in N_Entry_Body | N_Subprogram_Body
and then Is_List_Member (N)
and then List_Containing (N) = Statements (HSS);
end Is_Immediately_Within_Body;
--------------------
-- Is_Raise_Idiom --
--------------------
function Is_Raise_Idiom (N : Node_Id) return Boolean is
Raise_Stmt : Node_Id;
Stmt : Node_Id;
begin
if Is_Immediately_Within_Body (N) then
-- Assume that no raise statement has been seen yet
Raise_Stmt := Empty;
-- Examine the statements preceding the input node, skipping
-- internally-generated constructs.
Stmt := Prev (N);
while Present (Stmt) loop
-- Multiple raise statements violate the idiom
if Is_Raise_Statement (Stmt) then
if Present (Raise_Stmt) then
return False;
end if;
Raise_Stmt := Stmt;
elsif Comes_From_Source (Stmt) then
exit;
end if;
Stmt := Prev (Stmt);
end loop;
-- At this point the node must be preceded by a raise statement,
-- and the raise statement has to be the sole statement within
-- the enclosing entry or subprogram body.
return
Present (Raise_Stmt) and then Is_Sole_Statement (Raise_Stmt);
end if;
return False;
end Is_Raise_Idiom;
------------------------
-- Is_Raise_Statement --
------------------------
function Is_Raise_Statement (N : Node_Id) return Boolean is
begin
-- A raise statement may be transfomed into a Raise_xxx_Error node
return
Nkind (N) = N_Raise_Statement
or else Nkind (N) in N_Raise_xxx_Error;
end Is_Raise_Statement;
-----------------------
-- Is_Sole_Statement --
-----------------------
function Is_Sole_Statement (N : Node_Id) return Boolean is
Stmt : Node_Id;
begin
-- The input node appears within the statements of an entry or
-- subprogram body. Examine the statements preceding the node.
if Is_Immediately_Within_Body (N) then
Stmt := Prev (N);
while Present (Stmt) loop
-- The statement is preceded by another statement or a source
-- construct. This indicates that the node does not appear by
-- itself.
if Is_Control_Flow_Statement (Stmt)
or else Comes_From_Source (Stmt)
then
return False;
end if;
Stmt := Prev (Stmt);
end loop;
return True;
end if;
-- The input node is within a construct nested inside the entry or
-- subprogram body.
return False;
end Is_Sole_Statement;
----------------------------------------
-- Preceded_By_Control_Flow_Statement --
----------------------------------------
function Preceded_By_Control_Flow_Statement
(N : Node_Id) return Boolean
is
Stmt : Node_Id;
begin
if Is_List_Member (N) then
Stmt := Prev (N);
-- Examine the statements preceding the input node
while Present (Stmt) loop
if Is_Control_Flow_Statement (Stmt) then
return True;
end if;
Stmt := Prev (Stmt);
end loop;
return False;
end if;
-- Assume that the node is part of some control flow statement
return True;
end Preceded_By_Control_Flow_Statement;
----------------------------------
-- Within_Conditional_Statement --
----------------------------------
function Within_Conditional_Statement (N : Node_Id) return Boolean is
Stmt : Node_Id;
begin
Stmt := Parent (N);
while Present (Stmt) loop
if Is_Conditional_Statement (Stmt) then
return True;
-- Prevent the search from going too far
elsif Is_Body_Or_Package_Declaration (Stmt) then
exit;
end if;
Stmt := Parent (Stmt);
end loop;
return False;
end Within_Conditional_Statement;
-- Local variables
Call_Context : constant Node_Id :=
Enclosing_Declaration_Or_Statement (Call);
-- Start of processing for Check_Infinite_Recursion
begin
-- The call is assumed to be safe when the enclosing subprogram is
-- invoked with actuals other than its formals.
--
-- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
-- begin
-- ...
-- Proc (A1, A2, ..., AN);
-- ...
-- end Proc;
if Invoked_With_Different_Arguments (Call) then
return False;
-- The call is assumed to be safe when the invocation of the enclosing
-- subprogram depends on a conditional statement.
--
-- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
-- begin
-- ...
-- if Some_Condition then
-- Proc (F1, F2, ..., FN);
-- end if;
-- ...
-- end Proc;
elsif Within_Conditional_Statement (Call) then
return False;
-- The context of the call is assumed to be safe when the invocation of
-- the enclosing subprogram is preceded by some control flow statement.
--
-- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
-- begin
-- ...
-- if Some_Condition then
-- ...
-- end if;
-- ...
-- Proc (F1, F2, ..., FN);
-- ...
-- end Proc;
elsif Preceded_By_Control_Flow_Statement (Call_Context) then
return False;
-- Detect an idiom where the context of the call is preceded by a single
-- raise statement.
--
-- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
-- begin
-- raise ...;
-- Proc (F1, F2, ..., FN);
-- end Proc;
elsif Is_Raise_Idiom (Call_Context) then
return False;
end if;
-- At this point it is certain that infinite recursion will take place
-- as long as the call is executed. Detect a case where the context of
-- the call is the sole source statement within the subprogram body.
--
-- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
-- begin
-- Proc (F1, F2, ..., FN);
-- end Proc;
--
-- Install an explicit raise to prevent the infinite recursion.
if Is_Sole_Statement (Call_Context) then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("!infinite recursion<<", Call);
Error_Msg_N ("\!Storage_Error [<<", Call);
Insert_Action (Call,
Make_Raise_Storage_Error (Sloc (Call),
Reason => SE_Infinite_Recursion));
-- Otherwise infinite recursion could take place, considering other flow
-- control constructs such as gotos, exit statements, etc.
else
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("!possible infinite recursion<<", Call);
Error_Msg_N ("\!??Storage_Error ]<<", Call);
end if;
return True;
end Check_Infinite_Recursion;
---------------------------------------
-- Check_No_Direct_Boolean_Operators --
---------------------------------------
procedure Check_No_Direct_Boolean_Operators (N : Node_Id) is
begin
if Scope (Entity (N)) = Standard_Standard
and then Root_Type (Etype (Left_Opnd (N))) = Standard_Boolean
then
-- Restriction only applies to original source code
if Comes_From_Source (N) then
Check_Restriction (No_Direct_Boolean_Operators, N);
end if;
end if;
-- Do style check (but skip if in instance, error is on template)
if Style_Check then
if not In_Instance then
Check_Boolean_Operator (N);
end if;
end if;
end Check_No_Direct_Boolean_Operators;
------------------------------
-- Check_Parameterless_Call --
------------------------------
procedure Check_Parameterless_Call (N : Node_Id) is
Nam : Node_Id;
function Prefix_Is_Access_Subp return Boolean;
-- If the prefix is of an access_to_subprogram type, the node must be
-- rewritten as a call. Ditto if the prefix is overloaded and all its
-- interpretations are access to subprograms.
---------------------------
-- Prefix_Is_Access_Subp --
---------------------------
function Prefix_Is_Access_Subp return Boolean is
I : Interp_Index;
It : Interp;
begin
-- If the context is an attribute reference that can apply to
-- functions, this is never a parameterless call (RM 4.1.4(6)).
if Nkind (Parent (N)) = N_Attribute_Reference
and then Attribute_Name (Parent (N))
in Name_Address | Name_Code_Address | Name_Access
then
return False;
end if;
if not Is_Overloaded (N) then
return
Ekind (Etype (N)) = E_Subprogram_Type
and then Base_Type (Etype (Etype (N))) /= Standard_Void_Type;
else
Get_First_Interp (N, I, It);
while Present (It.Typ) loop
if Ekind (It.Typ) /= E_Subprogram_Type
or else Base_Type (Etype (It.Typ)) = Standard_Void_Type
then
return False;
end if;
Get_Next_Interp (I, It);
end loop;
return True;
end if;
end Prefix_Is_Access_Subp;
-- Start of processing for Check_Parameterless_Call
begin
-- Defend against junk stuff if errors already detected
if Total_Errors_Detected /= 0 then
if Nkind (N) in N_Has_Etype and then Etype (N) = Any_Type then
return;
elsif Nkind (N) in N_Has_Chars
and then not Is_Valid_Name (Chars (N))
then
return;
end if;
Require_Entity (N);
end if;
-- If the context expects a value, and the name is a procedure, this is
-- most likely a missing 'Access. Don't try to resolve the parameterless
-- call, error will be caught when the outer call is analyzed.
if Is_Entity_Name (N)
and then Ekind (Entity (N)) = E_Procedure
and then not Is_Overloaded (N)
and then
Nkind (Parent (N)) in N_Parameter_Association
| N_Function_Call
| N_Procedure_Call_Statement
then
return;
end if;
-- Rewrite as call if overloadable entity that is (or could be, in the
-- overloaded case) a function call. If we know for sure that the entity
-- is an enumeration literal, we do not rewrite it.
-- If the entity is the name of an operator, it cannot be a call because
-- operators cannot have default parameters. In this case, this must be
-- a string whose contents coincide with an operator name. Set the kind
-- of the node appropriately.
if (Is_Entity_Name (N)
and then Nkind (N) /= N_Operator_Symbol
and then Is_Overloadable (Entity (N))
and then (Ekind (Entity (N)) /= E_Enumeration_Literal
or else Is_Overloaded (N)))
-- Rewrite as call if it is an explicit dereference of an expression of
-- a subprogram access type, and the subprogram type is not that of a
-- procedure or entry.
or else
(Nkind (N) = N_Explicit_Dereference and then Prefix_Is_Access_Subp)
-- Rewrite as call if it is a selected component which is a function,
-- this is the case of a call to a protected function (which may be
-- overloaded with other protected operations).
or else
(Nkind (N) = N_Selected_Component
and then (Ekind (Entity (Selector_Name (N))) = E_Function
or else
(Ekind (Entity (Selector_Name (N))) in
E_Entry | E_Procedure
and then Is_Overloaded (Selector_Name (N)))))
-- If one of the above three conditions is met, rewrite as call. Apply
-- the rewriting only once.
then
if Nkind (Parent (N)) /= N_Function_Call
or else N /= Name (Parent (N))
then
-- This may be a prefixed call that was not fully analyzed, e.g.
-- an actual in an instance.
if Ada_Version >= Ada_2005
and then Nkind (N) = N_Selected_Component
and then Is_Dispatching_Operation (Entity (Selector_Name (N)))
then
Analyze_Selected_Component (N);
if Nkind (N) /= N_Selected_Component then
return;
end if;
end if;
-- The node is the name of the parameterless call. Preserve its
-- descendants, which may be complex expressions.
Nam := Relocate_Node (N);
-- If overloaded, overload set belongs to new copy
Save_Interps (N, Nam);
-- Change node to parameterless function call (note that the
-- Parameter_Associations associations field is left set to Empty,
-- its normal default value since there are no parameters)
Change_Node (N, N_Function_Call);
Set_Name (N, Nam);
Set_Sloc (N, Sloc (Nam));
Analyze_Call (N);
end if;
elsif Nkind (N) = N_Parameter_Association then
Check_Parameterless_Call (Explicit_Actual_Parameter (N));
elsif Nkind (N) = N_Operator_Symbol then
Change_Operator_Symbol_To_String_Literal (N);
Set_Is_Overloaded (N, False);
Set_Etype (N, Any_String);
end if;
end Check_Parameterless_Call;
--------------------------------
-- Is_Atomic_Ref_With_Address --
--------------------------------
function Is_Atomic_Ref_With_Address (N : Node_Id) return Boolean is
Pref : constant Node_Id := Prefix (N);
begin
if not Is_Entity_Name (Pref) then
return False;
else
declare
Pent : constant Entity_Id := Entity (Pref);
Ptyp : constant Entity_Id := Etype (Pent);
begin
return not Is_Access_Type (Ptyp)
and then (Is_Atomic (Ptyp) or else Is_Atomic (Pent))
and then Present (Address_Clause (Pent));
end;
end if;
end Is_Atomic_Ref_With_Address;
-----------------------------
-- Is_Definite_Access_Type --
-----------------------------
function Is_Definite_Access_Type (E : Entity_Id) return Boolean is
Btyp : constant Entity_Id := Base_Type (E);
begin
return Ekind (Btyp) = E_Access_Type
or else (Ekind (Btyp) = E_Access_Subprogram_Type
and then Comes_From_Source (Btyp));
end Is_Definite_Access_Type;
----------------------
-- Is_Predefined_Op --
----------------------
function Is_Predefined_Op (Nam : Entity_Id) return Boolean is
begin
-- Predefined operators are intrinsic subprograms
if not Is_Intrinsic_Subprogram (Nam) then
return False;
end if;
-- A call to a back-end builtin is never a predefined operator
if Is_Imported (Nam) and then Present (Interface_Name (Nam)) then
return False;
end if;
return not Is_Generic_Instance (Nam)
and then Chars (Nam) in Any_Operator_Name
and then (No (Alias (Nam)) or else Is_Predefined_Op (Alias (Nam)));
end Is_Predefined_Op;
-----------------------------
-- Make_Call_Into_Operator --
-----------------------------
procedure Make_Call_Into_Operator
(N : Node_Id;
Typ : Entity_Id;
Op_Id : Entity_Id)
is
Op_Name : constant Name_Id := Chars (Op_Id);
Act1 : Node_Id := First_Actual (N);
Act2 : Node_Id := Next_Actual (Act1);
Error : Boolean := False;
Func : constant Entity_Id := Entity (Name (N));
Is_Binary : constant Boolean := Present (Act2);
Op_Node : Node_Id;
Opnd_Type : Entity_Id := Empty;
Orig_Type : Entity_Id := Empty;
Pack : Entity_Id;
type Kind_Test is access function (E : Entity_Id) return Boolean;
function Operand_Type_In_Scope (S : Entity_Id) return Boolean;
-- If the operand is not universal, and the operator is given by an
-- expanded name, verify that the operand has an interpretation with a
-- type defined in the given scope of the operator.
function Type_In_P (Test : Kind_Test) return Entity_Id;
-- Find a type of the given class in package Pack that contains the
-- operator.
---------------------------
-- Operand_Type_In_Scope --
---------------------------
function Operand_Type_In_Scope (S : Entity_Id) return Boolean is
Nod : constant Node_Id := Right_Opnd (Op_Node);
I : Interp_Index;
It : Interp;
begin
if not Is_Overloaded (Nod) then
return Scope (Base_Type (Etype (Nod))) = S;
else
Get_First_Interp (Nod, I, It);
while Present (It.Typ) loop
if Scope (Base_Type (It.Typ)) = S then
return True;
end if;
Get_Next_Interp (I, It);
end loop;
return False;
end if;
end Operand_Type_In_Scope;
---------------
-- Type_In_P --
---------------
function Type_In_P (Test : Kind_Test) return Entity_Id is
E : Entity_Id;
function In_Decl return Boolean;
-- Verify that node is not part of the type declaration for the
-- candidate type, which would otherwise be invisible.
-------------
-- In_Decl --
-------------
function In_Decl return Boolean is
Decl_Node : constant Node_Id := Parent (E);
N2 : Node_Id;
begin
N2 := N;
if Etype (E) = Any_Type then
return True;
elsif No (Decl_Node) then
return False;
else
while Present (N2)
and then Nkind (N2) /= N_Compilation_Unit
loop
if N2 = Decl_Node then
return True;
else
N2 := Parent (N2);
end if;
end loop;
return False;
end if;
end In_Decl;
-- Start of processing for Type_In_P
begin
-- If the context type is declared in the prefix package, this is the
-- desired base type.
if Scope (Base_Type (Typ)) = Pack and then Test (Typ) then
return Base_Type (Typ);
else
E := First_Entity (Pack);
while Present (E) loop
if Test (E) and then not In_Decl then
return E;
end if;
Next_Entity (E);
end loop;
return Empty;
end if;
end Type_In_P;
-- Start of processing for Make_Call_Into_Operator
begin
Op_Node := New_Node (Operator_Kind (Op_Name, Is_Binary), Sloc (N));
-- Ensure that the corresponding operator has the same parent as the
-- original call. This guarantees that parent traversals performed by
-- the ABE mechanism succeed.
Set_Parent (Op_Node, Parent (N));
-- Binary operator
if Is_Binary then
Set_Left_Opnd (Op_Node, Relocate_Node (Act1));
Set_Right_Opnd (Op_Node, Relocate_Node (Act2));
Save_Interps (Act1, Left_Opnd (Op_Node));
Save_Interps (Act2, Right_Opnd (Op_Node));
Act1 := Left_Opnd (Op_Node);
Act2 := Right_Opnd (Op_Node);
-- Unary operator
else
Set_Right_Opnd (Op_Node, Relocate_Node (Act1));
Save_Interps (Act1, Right_Opnd (Op_Node));
Act1 := Right_Opnd (Op_Node);
end if;
-- If the operator is denoted by an expanded name, and the prefix is
-- not Standard, but the operator is a predefined one whose scope is
-- Standard, then this is an implicit_operator, inserted as an
-- interpretation by the procedure of the same name. This procedure
-- overestimates the presence of implicit operators, because it does
-- not examine the type of the operands. Verify now that the operand
-- type appears in the given scope. If right operand is universal,
-- check the other operand. In the case of concatenation, either
-- argument can be the component type, so check the type of the result.
-- If both arguments are literals, look for a type of the right kind
-- defined in the given scope. This elaborate nonsense is brought to
-- you courtesy of b33302a. The type itself must be frozen, so we must
-- find the type of the proper class in the given scope.
-- A final wrinkle is the multiplication operator for fixed point types,
-- which is defined in Standard only, and not in the scope of the
-- fixed point type itself.
if Nkind (Name (N)) = N_Expanded_Name then
Pack := Entity (Prefix (Name (N)));
-- If this is a package renaming, get renamed entity, which will be
-- the scope of the operands if operaton is type-correct.
if Present (Renamed_Entity (Pack)) then
Pack := Renamed_Entity (Pack);
end if;
-- If the entity being called is defined in the given package, it is
-- a renaming of a predefined operator, and known to be legal.
if Scope (Entity (Name (N))) = Pack
and then Pack /= Standard_Standard
then
null;
-- Visibility does not need to be checked in an instance: if the
-- operator was not visible in the generic it has been diagnosed
-- already, else there is an implicit copy of it in the instance.
elsif In_Instance then
null;
elsif Op_Name in Name_Op_Multiply | Name_Op_Divide
and then Is_Fixed_Point_Type (Etype (Act1))
and then Is_Fixed_Point_Type (Etype (Act2))
then
if Pack /= Standard_Standard then
Error := True;
end if;
-- Ada 2005 AI-420: Predefined equality on Universal_Access is
-- available.
elsif Ada_Version >= Ada_2005
and then Op_Name in Name_Op_Eq | Name_Op_Ne
and then (Is_Anonymous_Access_Type (Etype (Act1))
or else Is_Anonymous_Access_Type (Etype (Act2)))
then
null;
else
Opnd_Type := Base_Type (Etype (Right_Opnd (Op_Node)));
if Op_Name = Name_Op_Concat then
Opnd_Type := Base_Type (Typ);
elsif (Scope (Opnd_Type) = Standard_Standard
and then Is_Binary)
or else (Nkind (Right_Opnd (Op_Node)) = N_Attribute_Reference
and then Is_Binary
and then not Comes_From_Source (Opnd_Type))
then
Opnd_Type := Base_Type (Etype (Left_Opnd (Op_Node)));
end if;
if Scope (Opnd_Type) = Standard_Standard then
-- Verify that the scope contains a type that corresponds to
-- the given literal. Optimize the case where Pack is Standard.
if Pack /= Standard_Standard then
if Opnd_Type = Universal_Integer then
Orig_Type := Type_In_P (Is_Integer_Type'Access);
elsif Opnd_Type = Universal_Real then
Orig_Type := Type_In_P (Is_Real_Type'Access);
elsif Opnd_Type = Any_String then
Orig_Type := Type_In_P (Is_String_Type'Access);
elsif Opnd_Type = Any_Access then
Orig_Type := Type_In_P (Is_Definite_Access_Type'Access);
elsif Opnd_Type = Any_Composite then
Orig_Type := Type_In_P (Is_Composite_Type'Access);
if Present (Orig_Type) then
if Has_Private_Component (Orig_Type) then
Orig_Type := Empty;
else
Set_Etype (Act1, Orig_Type);
if Is_Binary then
Set_Etype (Act2, Orig_Type);
end if;
end if;
end if;
else
Orig_Type := Empty;
end if;
Error := No (Orig_Type);
end if;
elsif Ekind (Opnd_Type) = E_Allocator_Type
and then No (Type_In_P (Is_Definite_Access_Type'Access))
then
Error := True;
-- If the type is defined elsewhere, and the operator is not
-- defined in the given scope (by a renaming declaration, e.g.)
-- then this is an error as well. If an extension of System is
-- present, and the type may be defined there, Pack must be
-- System itself.
elsif Scope (Opnd_Type) /= Pack
and then Scope (Op_Id) /= Pack
and then (No (System_Aux_Id)
or else Scope (Opnd_Type) /= System_Aux_Id
or else Pack /= Scope (System_Aux_Id))
then
if not Is_Overloaded (Right_Opnd (Op_Node)) then
Error := True;
else
Error := not Operand_Type_In_Scope (Pack);
end if;
elsif Pack = Standard_Standard
and then not Operand_Type_In_Scope (Standard_Standard)
then
Error := True;
end if;
end if;
if Error then
Error_Msg_Node_2 := Pack;
Error_Msg_NE
("& not declared in&", N, Selector_Name (Name (N)));
Set_Etype (N, Any_Type);
return;
-- Detect a mismatch between the context type and the result type
-- in the named package, which is otherwise not detected if the
-- operands are universal. Check is only needed if source entity is
-- an operator, not a function that renames an operator.
elsif Nkind (Parent (N)) /= N_Type_Conversion
and then Ekind (Entity (Name (N))) = E_Operator
and then Is_Numeric_Type (Typ)
and then not Is_Universal_Numeric_Type (Typ)
and then Scope (Base_Type (Typ)) /= Pack
and then not In_Instance
then
if Is_Fixed_Point_Type (Typ)
and then Op_Name in Name_Op_Multiply | Name_Op_Divide
then
-- Already checked above
null;
-- Operator may be defined in an extension of System
elsif Present (System_Aux_Id)
and then Present (Opnd_Type)
and then Scope (Opnd_Type) = System_Aux_Id
then
null;
else
-- Could we use Wrong_Type here??? (this would require setting
-- Etype (N) to the actual type found where Typ was expected).
Error_Msg_NE ("expect }", N, Typ);
end if;
end if;
end if;
Set_Chars (Op_Node, Op_Name);
if not Is_Private_Type (Etype (N)) then
Set_Etype (Op_Node, Base_Type (Etype (N)));
else
Set_Etype (Op_Node, Etype (N));
end if;
-- If this is a call to a function that renames a predefined equality,
-- the renaming declaration provides a type that must be used to
-- resolve the operands. This must be done now because resolution of
-- the equality node will not resolve any remaining ambiguity, and it
-- assumes that the first operand is not overloaded.
if Op_Name in Name_Op_Eq | Name_Op_Ne
and then Ekind (Func) = E_Function
and then Is_Overloaded (Act1)
then
Resolve (Act1, Base_Type (Etype (First_Formal (Func))));
Resolve (Act2, Base_Type (Etype (First_Formal (Func))));
end if;
Set_Entity (Op_Node, Op_Id);
Generate_Reference (Op_Id, N, ' ');
-- Do rewrite setting Comes_From_Source on the result if the original
-- call came from source. Although it is not strictly the case that the
-- operator as such comes from the source, logically it corresponds
-- exactly to the function call in the source, so it should be marked
-- this way (e.g. to make sure that validity checks work fine).
declare
CS : constant Boolean := Comes_From_Source (N);
begin
Rewrite (N, Op_Node);
Set_Comes_From_Source (N, CS);
end;
-- If this is an arithmetic operator and the result type is private,
-- the operands and the result must be wrapped in conversion to
-- expose the underlying numeric type and expand the proper checks,
-- e.g. on division.
if Is_Private_Type (Typ) then
case Nkind (N) is
when N_Op_Add
| N_Op_Divide
| N_Op_Expon
| N_Op_Mod
| N_Op_Multiply
| N_Op_Rem
| N_Op_Subtract
=>
Resolve_Intrinsic_Operator (N, Typ);
when N_Op_Abs
| N_Op_Minus
| N_Op_Plus
=>
Resolve_Intrinsic_Unary_Operator (N, Typ);
when others =>
Resolve (N, Typ);
end case;
else
Resolve (N, Typ);
end if;
end Make_Call_Into_Operator;
-------------------
-- Operator_Kind --
-------------------
function Operator_Kind
(Op_Name : Name_Id;
Is_Binary : Boolean) return Node_Kind
is
Kind : Node_Kind;
begin
-- Use CASE statement or array???
if Is_Binary then
if Op_Name = Name_Op_And then
Kind := N_Op_And;
elsif Op_Name = Name_Op_Or then
Kind := N_Op_Or;
elsif Op_Name = Name_Op_Xor then
Kind := N_Op_Xor;
elsif Op_Name = Name_Op_Eq then
Kind := N_Op_Eq;
elsif Op_Name = Name_Op_Ne then
Kind := N_Op_Ne;
elsif Op_Name = Name_Op_Lt then
Kind := N_Op_Lt;
elsif Op_Name = Name_Op_Le then
Kind := N_Op_Le;
elsif Op_Name = Name_Op_Gt then
Kind := N_Op_Gt;
elsif Op_Name = Name_Op_Ge then
Kind := N_Op_Ge;
elsif Op_Name = Name_Op_Add then
Kind := N_Op_Add;
elsif Op_Name = Name_Op_Subtract then
Kind := N_Op_Subtract;
elsif Op_Name = Name_Op_Concat then
Kind := N_Op_Concat;
elsif Op_Name = Name_Op_Multiply then
Kind := N_Op_Multiply;
elsif Op_Name = Name_Op_Divide then
Kind := N_Op_Divide;
elsif Op_Name = Name_Op_Mod then
Kind := N_Op_Mod;
elsif Op_Name = Name_Op_Rem then
Kind := N_Op_Rem;
elsif Op_Name = Name_Op_Expon then
Kind := N_Op_Expon;
else
raise Program_Error;
end if;
-- Unary operators
else
if Op_Name = Name_Op_Add then
Kind := N_Op_Plus;
elsif Op_Name = Name_Op_Subtract then
Kind := N_Op_Minus;
elsif Op_Name = Name_Op_Abs then
Kind := N_Op_Abs;
elsif Op_Name = Name_Op_Not then
Kind := N_Op_Not;
else
raise Program_Error;
end if;
end if;
return Kind;
end Operator_Kind;
----------------------------
-- Preanalyze_And_Resolve --
----------------------------
procedure Preanalyze_And_Resolve
(N : Node_Id;
T : Entity_Id;
With_Freezing : Boolean)
is
Save_Full_Analysis : constant Boolean := Full_Analysis;
Save_Must_Not_Freeze : constant Boolean := Must_Not_Freeze (N);
Save_Preanalysis_Count : constant Nat :=
Inside_Preanalysis_Without_Freezing;
begin
pragma Assert (Nkind (N) in N_Subexpr);
if not With_Freezing then
Set_Must_Not_Freeze (N);
Inside_Preanalysis_Without_Freezing :=
Inside_Preanalysis_Without_Freezing + 1;
end if;
Full_Analysis := False;
Expander_Mode_Save_And_Set (False);
-- Normally, we suppress all checks for this preanalysis. There is no
-- point in processing them now, since they will be applied properly
-- and in the proper location when the default expressions reanalyzed
-- and reexpanded later on. We will also have more information at that
-- point for possible suppression of individual checks.
-- However, in SPARK mode, most expansion is suppressed, and this
-- later reanalysis and reexpansion may not occur. SPARK mode does
-- require the setting of checking flags for proof purposes, so we
-- do the SPARK preanalysis without suppressing checks.
-- This special handling for SPARK mode is required for example in the
-- case of Ada 2012 constructs such as quantified expressions, which are
-- expanded in two separate steps.
if GNATprove_Mode then
Analyze_And_Resolve (N, T);
else
Analyze_And_Resolve (N, T, Suppress => All_Checks);
end if;
Expander_Mode_Restore;
Full_Analysis := Save_Full_Analysis;
Set_Must_Not_Freeze (N, Save_Must_Not_Freeze);
if not With_Freezing then
Inside_Preanalysis_Without_Freezing :=
Inside_Preanalysis_Without_Freezing - 1;
end if;
pragma Assert
(Inside_Preanalysis_Without_Freezing = Save_Preanalysis_Count);
end Preanalyze_And_Resolve;
----------------------------
-- Preanalyze_And_Resolve --
----------------------------
procedure Preanalyze_And_Resolve (N : Node_Id; T : Entity_Id) is
begin
Preanalyze_And_Resolve (N, T, With_Freezing => False);
end Preanalyze_And_Resolve;
-- Version without context type
procedure Preanalyze_And_Resolve (N : Node_Id) is
Save_Full_Analysis : constant Boolean := Full_Analysis;
begin
Full_Analysis := False;
Expander_Mode_Save_And_Set (False);
Analyze (N);
Resolve (N, Etype (N), Suppress => All_Checks);
Expander_Mode_Restore;
Full_Analysis := Save_Full_Analysis;
end Preanalyze_And_Resolve;
------------------------------------------
-- Preanalyze_With_Freezing_And_Resolve --
------------------------------------------
procedure Preanalyze_With_Freezing_And_Resolve
(N : Node_Id;
T : Entity_Id)
is
begin
Preanalyze_And_Resolve (N, T, With_Freezing => True);
end Preanalyze_With_Freezing_And_Resolve;
----------------------------------
-- Replace_Actual_Discriminants --
----------------------------------
procedure Replace_Actual_Discriminants (N : Node_Id; Default : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Tsk : Node_Id := Empty;
function Process_Discr (Nod : Node_Id) return Traverse_Result;
-- Comment needed???
-------------------
-- Process_Discr --
-------------------
function Process_Discr (Nod : Node_Id) return Traverse_Result is
Ent : Entity_Id;
begin
if Nkind (Nod) = N_Identifier then
Ent := Entity (Nod);
if Present (Ent)
and then Ekind (Ent) = E_Discriminant
then
Rewrite (Nod,
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Tsk, New_Sloc => Loc),
Selector_Name => Make_Identifier (Loc, Chars (Ent))));
Set_Etype (Nod, Etype (Ent));
end if;
end if;
return OK;
end Process_Discr;
procedure Replace_Discrs is new Traverse_Proc (Process_Discr);
-- Start of processing for Replace_Actual_Discriminants
begin
if Expander_Active then
null;
-- Allow the replacement of concurrent discriminants in GNATprove even
-- though this is a light expansion activity. Note that generic units
-- are not modified.
elsif GNATprove_Mode and not Inside_A_Generic then
null;
else
return;
end if;
if Nkind (Name (N)) = N_Selected_Component then
Tsk := Prefix (Name (N));
elsif Nkind (Name (N)) = N_Indexed_Component then
Tsk := Prefix (Prefix (Name (N)));
end if;
if Present (Tsk) then
Replace_Discrs (Default);
end if;
end Replace_Actual_Discriminants;
-------------
-- Resolve --
-------------
procedure Resolve (N : Node_Id; Typ : Entity_Id) is
Ambiguous : Boolean := False;
Ctx_Type : Entity_Id := Typ;
Expr_Type : Entity_Id := Empty; -- prevent junk warning
Err_Type : Entity_Id := Empty;
Found : Boolean := False;
From_Lib : Boolean;
I : Interp_Index;
I1 : Interp_Index := 0; -- prevent junk warning
It : Interp;
It1 : Interp;
Seen : Entity_Id := Empty; -- prevent junk warning
function Comes_From_Predefined_Lib_Unit (Nod : Node_Id) return Boolean;
-- Determine whether a node comes from a predefined library unit or
-- Standard.
procedure Patch_Up_Value (N : Node_Id; Typ : Entity_Id);
-- Try and fix up a literal so that it matches its expected type. New
-- literals are manufactured if necessary to avoid cascaded errors.
procedure Report_Ambiguous_Argument;
-- Additional diagnostics when an ambiguous call has an ambiguous
-- argument (typically a controlling actual).
procedure Resolution_Failed;
-- Called when attempt at resolving current expression fails
------------------------------------
-- Comes_From_Predefined_Lib_Unit --
-------------------------------------
function Comes_From_Predefined_Lib_Unit (Nod : Node_Id) return Boolean is
begin
return
Sloc (Nod) = Standard_Location or else In_Predefined_Unit (Nod);
end Comes_From_Predefined_Lib_Unit;
--------------------
-- Patch_Up_Value --
--------------------
procedure Patch_Up_Value (N : Node_Id; Typ : Entity_Id) is
begin
if Nkind (N) = N_Integer_Literal and then Is_Real_Type (Typ) then
Rewrite (N,
Make_Real_Literal (Sloc (N),
Realval => UR_From_Uint (Intval (N))));
Set_Etype (N, Universal_Real);
Set_Is_Static_Expression (N);
elsif Nkind (N) = N_Real_Literal and then Is_Integer_Type (Typ) then
Rewrite (N,
Make_Integer_Literal (Sloc (N),
Intval => UR_To_Uint (Realval (N))));
Set_Etype (N, Universal_Integer);
Set_Is_Static_Expression (N);
elsif Nkind (N) = N_String_Literal
and then Is_Character_Type (Typ)
then
Set_Character_Literal_Name (Char_Code (Character'Pos ('A')));
Rewrite (N,
Make_Character_Literal (Sloc (N),
Chars => Name_Find,
Char_Literal_Value =>
UI_From_Int (Character'Pos ('A'))));
Set_Etype (N, Any_Character);
Set_Is_Static_Expression (N);
elsif Nkind (N) /= N_String_Literal and then Is_String_Type (Typ) then
Rewrite (N,
Make_String_Literal (Sloc (N),
Strval => End_String));
elsif Nkind (N) = N_Range then
Patch_Up_Value (Low_Bound (N), Typ);
Patch_Up_Value (High_Bound (N), Typ);
end if;
end Patch_Up_Value;
-------------------------------
-- Report_Ambiguous_Argument --
-------------------------------
procedure Report_Ambiguous_Argument is
Arg : constant Node_Id := First (Parameter_Associations (N));
I : Interp_Index;
It : Interp;
begin
if Nkind (Arg) = N_Function_Call
and then Is_Entity_Name (Name (Arg))
and then Is_Overloaded (Name (Arg))
then
Error_Msg_NE ("ambiguous call to&", Arg, Name (Arg));
-- Examine possible interpretations, and adapt the message
-- for inherited subprograms declared by a type derivation.
Get_First_Interp (Name (Arg), I, It);
while Present (It.Nam) loop
Error_Msg_Sloc := Sloc (It.Nam);
if Nkind (Parent (It.Nam)) = N_Full_Type_Declaration then
Error_Msg_N ("interpretation (inherited) #!", Arg);
else
Error_Msg_N ("interpretation #!", Arg);
end if;
Get_Next_Interp (I, It);
end loop;
end if;
-- Additional message and hint if the ambiguity involves an Ada2020
-- container aggregate.
Check_Ambiguous_Aggregate (N);
end Report_Ambiguous_Argument;
-----------------------
-- Resolution_Failed --
-----------------------
procedure Resolution_Failed is
begin
Patch_Up_Value (N, Typ);
-- Set the type to the desired one to minimize cascaded errors. Note
-- that this is an approximation and does not work in all cases.
Set_Etype (N, Typ);
Debug_A_Exit ("resolving ", N, " (done, resolution failed)");
Set_Is_Overloaded (N, False);
-- The caller will return without calling the expander, so we need
-- to set the analyzed flag. Note that it is fine to set Analyzed
-- to True even if we are in the middle of a shallow analysis,
-- (see the spec of sem for more details) since this is an error
-- situation anyway, and there is no point in repeating the
-- analysis later (indeed it won't work to repeat it later, since
-- we haven't got a clear resolution of which entity is being
-- referenced.)
Set_Analyzed (N, True);
return;
end Resolution_Failed;
Literal_Aspect_Map :
constant array (N_Numeric_Or_String_Literal) of Aspect_Id :=
(N_Integer_Literal => Aspect_Integer_Literal,
N_Real_Literal => Aspect_Real_Literal,
N_String_Literal => Aspect_String_Literal);
Named_Number_Aspect_Map : constant array (Named_Kind) of Aspect_Id :=
(E_Named_Integer => Aspect_Integer_Literal,
E_Named_Real => Aspect_Real_Literal);
-- Start of processing for Resolve
begin
if N = Error then
return;
end if;
-- Access attribute on remote subprogram cannot be used for a non-remote
-- access-to-subprogram type.
if Nkind (N) = N_Attribute_Reference
and then Attribute_Name (N) in Name_Access
| Name_Unrestricted_Access
| Name_Unchecked_Access
and then Comes_From_Source (N)
and then Is_Entity_Name (Prefix (N))
and then Is_Subprogram (Entity (Prefix (N)))
and then Is_Remote_Call_Interface (Entity (Prefix (N)))
and then not Is_Remote_Access_To_Subprogram_Type (Typ)
then
Error_Msg_N
("prefix must statically denote a non-remote subprogram", N);
end if;
From_Lib := Comes_From_Predefined_Lib_Unit (N);
-- If the context is a Remote_Access_To_Subprogram, access attributes
-- must be resolved with the corresponding fat pointer. There is no need
-- to check for the attribute name since the return type of an
-- attribute is never a remote type.
if Nkind (N) = N_Attribute_Reference
and then Comes_From_Source (N)
and then (Is_Remote_Call_Interface (Typ) or else Is_Remote_Types (Typ))
then
declare
Attr : constant Attribute_Id :=
Get_Attribute_Id (Attribute_Name (N));
Pref : constant Node_Id := Prefix (N);
Decl : Node_Id;
Spec : Node_Id;
Is_Remote : Boolean := True;
begin
-- Check that Typ is a remote access-to-subprogram type
if Is_Remote_Access_To_Subprogram_Type (Typ) then
-- Prefix (N) must statically denote a remote subprogram
-- declared in a package specification.
if Attr = Attribute_Access or else
Attr = Attribute_Unchecked_Access or else
Attr = Attribute_Unrestricted_Access
then
Decl := Unit_Declaration_Node (Entity (Pref));
if Nkind (Decl) = N_Subprogram_Body then
Spec := Corresponding_Spec (Decl);
if Present (Spec) then
Decl := Unit_Declaration_Node (Spec);
end if;
end if;
Spec := Parent (Decl);
if not Is_Entity_Name (Prefix (N))
or else Nkind (Spec) /= N_Package_Specification
or else
not Is_Remote_Call_Interface (Defining_Entity (Spec))
then
Is_Remote := False;
Error_Msg_N
("prefix must statically denote a remote subprogram ",
N);
end if;
-- If we are generating code in distributed mode, perform
-- semantic checks against corresponding remote entities.
if Expander_Active
and then Get_PCS_Name /= Name_No_DSA
then
Check_Subtype_Conformant
(New_Id => Entity (Prefix (N)),
Old_Id => Designated_Type
(Corresponding_Remote_Type (Typ)),
Err_Loc => N);
if Is_Remote then
Process_Remote_AST_Attribute (N, Typ);
end if;
end if;
end if;
end if;
end;
end if;
Debug_A_Entry ("resolving ", N);
if Debug_Flag_V then
Write_Overloads (N);
end if;
if Comes_From_Source (N) then
if Is_Fixed_Point_Type (Typ) then
Check_Restriction (No_Fixed_Point, N);
elsif Is_Floating_Point_Type (Typ)
and then Typ /= Universal_Real
and then Typ /= Any_Real
then
Check_Restriction (No_Floating_Point, N);
end if;
end if;
-- Return if already analyzed
if Analyzed (N) then
Debug_A_Exit ("resolving ", N, " (done, already analyzed)");
Analyze_Dimension (N);
return;
-- Any case of Any_Type as the Etype value means that we had a
-- previous error.
elsif Etype (N) = Any_Type then
Debug_A_Exit ("resolving ", N, " (done, Etype = Any_Type)");
return;
end if;
Check_Parameterless_Call (N);
-- The resolution of an Expression_With_Actions is determined by
-- its Expression, but if the node comes from source it is a
-- Declare_Expression and requires scope management.
if Nkind (N) = N_Expression_With_Actions then
if Comes_From_Source (N) and then N = Original_Node (N) then
Resolve_Declare_Expression (N, Typ);
else
Resolve (Expression (N), Typ);
end if;
Found := True;
Expr_Type := Etype (Expression (N));
-- If not overloaded, then we know the type, and all that needs doing
-- is to check that this type is compatible with the context.
elsif not Is_Overloaded (N) then
Found := Covers (Typ, Etype (N));
Expr_Type := Etype (N);
-- In the overloaded case, we must select the interpretation that
-- is compatible with the context (i.e. the type passed to Resolve)
else
-- Loop through possible interpretations
Get_First_Interp (N, I, It);
Interp_Loop : while Present (It.Typ) loop
if Debug_Flag_V then
Write_Str ("Interp: ");
Write_Interp (It);
end if;
-- We are only interested in interpretations that are compatible
-- with the expected type, any other interpretations are ignored.
if not Covers (Typ, It.Typ) then
if Debug_Flag_V then
Write_Str (" interpretation incompatible with context");
Write_Eol;
end if;
else
-- Skip the current interpretation if it is disabled by an
-- abstract operator. This action is performed only when the
-- type against which we are resolving is the same as the
-- type of the interpretation.
if Ada_Version >= Ada_2005
and then It.Typ = Typ
and then Typ /= Universal_Integer
and then Typ /= Universal_Real
and then Present (It.Abstract_Op)
then
if Debug_Flag_V then
Write_Line ("Skip.");
end if;
goto Continue;
end if;
-- First matching interpretation
if not Found then
Found := True;
I1 := I;
Seen := It.Nam;
Expr_Type := It.Typ;
-- Matching interpretation that is not the first, maybe an
-- error, but there are some cases where preference rules are
-- used to choose between the two possibilities. These and
-- some more obscure cases are handled in Disambiguate.
else
-- If the current statement is part of a predefined library
-- unit, then all interpretations which come from user level
-- packages should not be considered. Check previous and
-- current one.
if From_Lib then
if not Comes_From_Predefined_Lib_Unit (It.Nam) then
goto Continue;
elsif not Comes_From_Predefined_Lib_Unit (Seen) then
-- Previous interpretation must be discarded
I1 := I;
Seen := It.Nam;
Expr_Type := It.Typ;
Set_Entity (N, Seen);
goto Continue;
end if;
end if;
-- Otherwise apply further disambiguation steps
Error_Msg_Sloc := Sloc (Seen);
It1 := Disambiguate (N, I1, I, Typ);
-- Disambiguation has succeeded. Skip the remaining
-- interpretations.
if It1 /= No_Interp then
Seen := It1.Nam;
Expr_Type := It1.Typ;
while Present (It.Typ) loop
Get_Next_Interp (I, It);
end loop;
else
-- Before we issue an ambiguity complaint, check for the
-- case of a subprogram call where at least one of the
-- arguments is Any_Type, and if so suppress the message,
-- since it is a cascaded error. This can also happen for
-- a generalized indexing operation.
if Nkind (N) in N_Subprogram_Call
or else (Nkind (N) = N_Indexed_Component
and then Present (Generalized_Indexing (N)))
then
declare
A : Node_Id;
E : Node_Id;
begin
if Nkind (N) = N_Indexed_Component then
Rewrite (N, Generalized_Indexing (N));
end if;
A := First_Actual (N);
while Present (A) loop
E := A;
if Nkind (E) = N_Parameter_Association then
E := Explicit_Actual_Parameter (E);
end if;
if Etype (E) = Any_Type then
if Debug_Flag_V then
Write_Str ("Any_Type in call");
Write_Eol;
end if;
exit Interp_Loop;
end if;
Next_Actual (A);
end loop;
end;
elsif Nkind (N) in N_Binary_Op
and then (Etype (Left_Opnd (N)) = Any_Type
or else Etype (Right_Opnd (N)) = Any_Type)
then
exit Interp_Loop;
elsif Nkind (N) in N_Unary_Op
and then Etype (Right_Opnd (N)) = Any_Type
then
exit Interp_Loop;
end if;
-- Not that special case, so issue message using the flag
-- Ambiguous to control printing of the header message
-- only at the start of an ambiguous set.
if not Ambiguous then
if Nkind (N) = N_Function_Call
and then Nkind (Name (N)) = N_Explicit_Dereference
then
Error_Msg_N
("ambiguous expression (cannot resolve indirect "
& "call)!", N);
else
Error_Msg_NE -- CODEFIX
("ambiguous expression (cannot resolve&)!",
N, It.Nam);
end if;
Ambiguous := True;
if Nkind (Parent (Seen)) = N_Full_Type_Declaration then
Error_Msg_N
("\\possible interpretation (inherited)#!", N);
else
Error_Msg_N -- CODEFIX
("\\possible interpretation#!", N);
end if;
if Nkind (N) in N_Subprogram_Call
and then Present (Parameter_Associations (N))
then
Report_Ambiguous_Argument;
end if;
end if;
Error_Msg_Sloc := Sloc (It.Nam);
-- By default, the error message refers to the candidate
-- interpretation. But if it is a predefined operator, it
-- is implicitly declared at the declaration of the type
-- of the operand. Recover the sloc of that declaration
-- for the error message.
if Nkind (N) in N_Op
and then Scope (It.Nam) = Standard_Standard
and then not Is_Overloaded (Right_Opnd (N))
and then Scope (Base_Type (Etype (Right_Opnd (N)))) /=
Standard_Standard
then
Err_Type := First_Subtype (Etype (Right_Opnd (N)));
if Comes_From_Source (Err_Type)
and then Present (Parent (Err_Type))
then
Error_Msg_Sloc := Sloc (Parent (Err_Type));
end if;
elsif Nkind (N) in N_Binary_Op
and then Scope (It.Nam) = Standard_Standard
and then not Is_Overloaded (Left_Opnd (N))
and then Scope (Base_Type (Etype (Left_Opnd (N)))) /=
Standard_Standard
then
Err_Type := First_Subtype (Etype (Left_Opnd (N)));
if Comes_From_Source (Err_Type)
and then Present (Parent (Err_Type))
then
Error_Msg_Sloc := Sloc (Parent (Err_Type));
end if;
-- If this is an indirect call, use the subprogram_type
-- in the message, to have a meaningful location. Also
-- indicate if this is an inherited operation, created
-- by a type declaration.
elsif Nkind (N) = N_Function_Call
and then Nkind (Name (N)) = N_Explicit_Dereference
and then Is_Type (It.Nam)
then
Err_Type := It.Nam;
Error_Msg_Sloc :=
Sloc (Associated_Node_For_Itype (Err_Type));
else
Err_Type := Empty;
end if;
if Nkind (N) in N_Op
and then Scope (It.Nam) = Standard_Standard
and then Present (Err_Type)
then
-- Special-case the message for universal_fixed
-- operators, which are not declared with the type
-- of the operand, but appear forever in Standard.
if It.Typ = Universal_Fixed
and then Scope (It.Nam) = Standard_Standard
then
Error_Msg_N
("\\possible interpretation as universal_fixed "
& "operation (RM 4.5.5 (19))", N);
else
Error_Msg_N
("\\possible interpretation (predefined)#!", N);
end if;
elsif
Nkind (Parent (It.Nam)) = N_Full_Type_Declaration
then
Error_Msg_N
("\\possible interpretation (inherited)#!", N);
else
Error_Msg_N -- CODEFIX
("\\possible interpretation#!", N);
end if;
end if;
end if;
-- We have a matching interpretation, Expr_Type is the type
-- from this interpretation, and Seen is the entity.
-- For an operator, just set the entity name. The type will be
-- set by the specific operator resolution routine.
if Nkind (N) in N_Op then
Set_Entity (N, Seen);
Generate_Reference (Seen, N);
elsif Nkind (N) in N_Case_Expression
| N_Character_Literal
| N_Delta_Aggregate
| N_If_Expression
then
Set_Etype (N, Expr_Type);
-- AI05-0139-2: Expression is overloaded because type has
-- implicit dereference. The context may be the one that
-- requires implicit dereferemce.
elsif Has_Implicit_Dereference (Expr_Type) then
Set_Etype (N, Expr_Type);
Set_Is_Overloaded (N, False);
-- If the expression is an entity, generate a reference
-- to it, as this is not done for an overloaded construct
-- during analysis.
if Is_Entity_Name (N)
and then Comes_From_Source (N)
then
Generate_Reference (Entity (N), N);
-- Examine access discriminants of entity type,
-- to check whether one of them yields the
-- expected type.
declare
Disc : Entity_Id :=
First_Discriminant (Etype (Entity (N)));
begin
while Present (Disc) loop
exit when Is_Access_Type (Etype (Disc))
and then Has_Implicit_Dereference (Disc)
and then Designated_Type (Etype (Disc)) = Typ;
Next_Discriminant (Disc);
end loop;
if Present (Disc) then
Build_Explicit_Dereference (N, Disc);
end if;
end;
end if;
exit Interp_Loop;
elsif Is_Overloaded (N)
and then Present (It.Nam)
and then Ekind (It.Nam) = E_Discriminant
and then Has_Implicit_Dereference (It.Nam)
then
-- If the node is a general indexing, the dereference is
-- is inserted when resolving the rewritten form, else
-- insert it now.
if Nkind (N) /= N_Indexed_Component
or else No (Generalized_Indexing (N))
then
Build_Explicit_Dereference (N, It.Nam);
end if;
-- For an explicit dereference, attribute reference, range,
-- short-circuit form (which is not an operator node), or call
-- with a name that is an explicit dereference, there is
-- nothing to be done at this point.
elsif Nkind (N) in N_Attribute_Reference
| N_And_Then
| N_Explicit_Dereference
| N_Identifier
| N_Indexed_Component
| N_Or_Else
| N_Range
| N_Selected_Component
| N_Slice
or else Nkind (Name (N)) = N_Explicit_Dereference
then
null;
-- For procedure or function calls, set the type of the name,
-- and also the entity pointer for the prefix.
elsif Nkind (N) in N_Subprogram_Call
and then Is_Entity_Name (Name (N))
then
Set_Etype (Name (N), Expr_Type);
Set_Entity (Name (N), Seen);
Generate_Reference (Seen, Name (N));
elsif Nkind (N) = N_Function_Call
and then Nkind (Name (N)) = N_Selected_Component
then
Set_Etype (Name (N), Expr_Type);
Set_Entity (Selector_Name (Name (N)), Seen);
Generate_Reference (Seen, Selector_Name (Name (N)));
-- For all other cases, just set the type of the Name
else
Set_Etype (Name (N), Expr_Type);
end if;
end if;
<<Continue>>
-- Move to next interpretation
exit Interp_Loop when No (It.Typ);
Get_Next_Interp (I, It);
end loop Interp_Loop;
end if;
-- At this stage Found indicates whether or not an acceptable
-- interpretation exists. If not, then we have an error, except that if
-- the context is Any_Type as a result of some other error, then we
-- suppress the error report.
if not Found then
if Typ /= Any_Type then
-- If type we are looking for is Void, then this is the procedure
-- call case, and the error is simply that what we gave is not a
-- procedure name (we think of procedure calls as expressions with
-- types internally, but the user doesn't think of them this way).
if Typ = Standard_Void_Type then
-- Special case message if function used as a procedure
if Nkind (N) = N_Procedure_Call_Statement
and then Is_Entity_Name (Name (N))
and then Ekind (Entity (Name (N))) = E_Function
then
Error_Msg_NE
("cannot use call to function & as a statement",
Name (N), Entity (Name (N)));
Error_Msg_N
("\return value of a function call cannot be ignored",
Name (N));
-- Otherwise give general message (not clear what cases this
-- covers, but no harm in providing for them).
else
Error_Msg_N ("expect procedure name in procedure call", N);
end if;
Found := True;
-- Otherwise we do have a subexpression with the wrong type
-- Check for the case of an allocator which uses an access type
-- instead of the designated type. This is a common error and we
-- specialize the message, posting an error on the operand of the
-- allocator, complaining that we expected the designated type of
-- the allocator.
elsif Nkind (N) = N_Allocator
and then Is_Access_Type (Typ)
and then Is_Access_Type (Etype (N))
and then Designated_Type (Etype (N)) = Typ
then
Wrong_Type (Expression (N), Designated_Type (Typ));
Found := True;
-- Check for view mismatch on Null in instances, for which the
-- view-swapping mechanism has no identifier.
elsif (In_Instance or else In_Inlined_Body)
and then (Nkind (N) = N_Null)
and then Is_Private_Type (Typ)
and then Is_Access_Type (Full_View (Typ))
then
Resolve (N, Full_View (Typ));
Set_Etype (N, Typ);
return;
-- Check for an aggregate. Sometimes we can get bogus aggregates
-- from misuse of parentheses, and we are about to complain about
-- the aggregate without even looking inside it.
-- Instead, if we have an aggregate of type Any_Composite, then
-- analyze and resolve the component fields, and then only issue
-- another message if we get no errors doing this (otherwise
-- assume that the errors in the aggregate caused the problem).
elsif Nkind (N) = N_Aggregate
and then Etype (N) = Any_Composite
then
if Ada_Version >= Ada_2020
and then Has_Aspect (Typ, Aspect_Aggregate)
then
Resolve_Container_Aggregate (N, Typ);
if Expander_Active then
Expand (N);
end if;
return;
end if;
-- Disable expansion in any case. If there is a type mismatch
-- it may be fatal to try to expand the aggregate. The flag
-- would otherwise be set to false when the error is posted.
Expander_Active := False;
declare
procedure Check_Aggr (Aggr : Node_Id);
-- Check one aggregate, and set Found to True if we have a
-- definite error in any of its elements
procedure Check_Elmt (Aelmt : Node_Id);
-- Check one element of aggregate and set Found to True if
-- we definitely have an error in the element.
----------------
-- Check_Aggr --
----------------
procedure Check_Aggr (Aggr : Node_Id) is
Elmt : Node_Id;
begin
if Present (Expressions (Aggr)) then
Elmt := First (Expressions (Aggr));
while Present (Elmt) loop
Check_Elmt (Elmt);
Next (Elmt);
end loop;
end if;
if Present (Component_Associations (Aggr)) then
Elmt := First (Component_Associations (Aggr));
while Present (Elmt) loop
-- If this is a default-initialized component, then
-- there is nothing to check. The box will be
-- replaced by the appropriate call during late
-- expansion.
if Nkind (Elmt) /= N_Iterated_Component_Association
and then not Box_Present (Elmt)
then
Check_Elmt (Expression (Elmt));
end if;
Next (Elmt);
end loop;
end if;
end Check_Aggr;
----------------
-- Check_Elmt --
----------------
procedure Check_Elmt (Aelmt : Node_Id) is
begin
-- If we have a nested aggregate, go inside it (to
-- attempt a naked analyze-resolve of the aggregate can
-- cause undesirable cascaded errors). Do not resolve
-- expression if it needs a type from context, as for
-- integer * fixed expression.
if Nkind (Aelmt) = N_Aggregate then
Check_Aggr (Aelmt);
else
Analyze (Aelmt);
if not Is_Overloaded (Aelmt)
and then Etype (Aelmt) /= Any_Fixed
then
Resolve (Aelmt);
end if;
if Etype (Aelmt) = Any_Type then
Found := True;
end if;
end if;
end Check_Elmt;
begin
Check_Aggr (N);
end;
end if;
-- Rewrite Literal as a call if the corresponding literal aspect
-- is set.
if (Nkind (N) in N_Numeric_Or_String_Literal
and then
Present
(Find_Aspect (Typ, Literal_Aspect_Map (Nkind (N)))))
or else
(Nkind (N) = N_Identifier
and then Is_Named_Number (Entity (N))
and then
Present
(Find_Aspect
(Typ, Named_Number_Aspect_Map (Ekind (Entity (N))))))
then
declare
Lit_Aspect : constant Aspect_Id :=
(if Nkind (N) = N_Identifier
then Named_Number_Aspect_Map (Ekind (Entity (N)))
else Literal_Aspect_Map (Nkind (N)));
Loc : constant Source_Ptr := Sloc (N);
Callee : Entity_Id :=
Entity (Expression (Find_Aspect (Typ, Lit_Aspect)));
Name : constant Node_Id :=
Make_Identifier (Loc, Chars (Callee));
Param1 : Node_Id;
Param2 : Node_Id;
Params : List_Id;
Call : Node_Id;
Expr : Node_Id;
begin
if Nkind (N) = N_Identifier then
Expr := Expression (Declaration_Node (Entity (N)));
if Ekind (Entity (N)) = E_Named_Integer then
UI_Image (Expr_Value (Expr), Decimal);
Start_String;
Store_String_Chars
(UI_Image_Buffer (1 .. UI_Image_Length));
Param1 := Make_String_Literal (Loc, End_String);
Params := New_List (Param1);
else
UI_Image (Norm_Num (Expr_Value_R (Expr)), Decimal);
Start_String;
Store_String_Chars
(UI_Image_Buffer (1 .. UI_Image_Length));
Param1 := Make_String_Literal (Loc, End_String);
-- Note: Set_Etype is called below on Param1
UI_Image (Norm_Den (Expr_Value_R (Expr)), Decimal);
Start_String;
Store_String_Chars
(UI_Image_Buffer (1 .. UI_Image_Length));
Param2 := Make_String_Literal (Loc, End_String);
Set_Etype (Param2, Standard_String);
Params := New_List (Param1, Param2);
if Present (Related_Expression (Callee)) then
Callee := Related_Expression (Callee);
else
Error_Msg_NE
("cannot resolve & for a named real", N, Callee);
return;
end if;
end if;
elsif Nkind (N) = N_String_Literal then
Param1 := Make_String_Literal (Loc, Strval (N));
Params := New_List (Param1);
else
Param1 :=
Make_String_Literal
(Loc, String_From_Numeric_Literal (N));
Params := New_List (Param1);
end if;
Call :=
Make_Function_Call
(Sloc => Loc,
Name => Name,
Parameter_Associations => Params);
Set_Entity (Name, Callee);
Set_Is_Overloaded (Name, False);
if Lit_Aspect = Aspect_String_Literal then
Set_Etype (Param1, Standard_Wide_Wide_String);
else
Set_Etype (Param1, Standard_String);
end if;
Set_Etype (Call, Etype (Callee));
-- Conversion needed in case of an inherited aspect
-- of a derived type.
--
-- ??? Need to do something different here for downward
-- tagged conversion case (which is only possible in the
-- case of a null extension); the current call to
-- Convert_To results in an error message about an illegal
-- downward conversion.
Call := Convert_To (Typ, Call);
Rewrite (N, Call);
end;
Analyze_And_Resolve (N, Typ);
return;
end if;
-- Looks like we have a type error, but check for special case
-- of Address wanted, integer found, with the configuration pragma
-- Allow_Integer_Address active. If we have this case, introduce
-- an unchecked conversion to allow the integer expression to be
-- treated as an Address. The reverse case of integer wanted,
-- Address found, is treated in an analogous manner.
if Address_Integer_Convert_OK (Typ, Etype (N)) then
Rewrite (N, Unchecked_Convert_To (Typ, Relocate_Node (N)));
Analyze_And_Resolve (N, Typ);
return;
-- Under relaxed RM semantics silently replace occurrences of null
-- by System.Null_Address.
elsif Null_To_Null_Address_Convert_OK (N, Typ) then
Replace_Null_By_Null_Address (N);
Analyze_And_Resolve (N, Typ);
return;
end if;
-- That special Allow_Integer_Address check did not apply, so we
-- have a real type error. If an error message was issued already,
-- Found got reset to True, so if it's still False, issue standard
-- Wrong_Type message.
if not Found then
if Is_Overloaded (N) and then Nkind (N) = N_Function_Call then
declare
Subp_Name : Node_Id;
begin
if Is_Entity_Name (Name (N)) then
Subp_Name := Name (N);
elsif Nkind (Name (N)) = N_Selected_Component then
-- Protected operation: retrieve operation name
Subp_Name := Selector_Name (Name (N));
else
raise Program_Error;
end if;
Error_Msg_Node_2 := Typ;
Error_Msg_NE
("no visible interpretation of& matches expected type&",
N, Subp_Name);
end;
if All_Errors_Mode then
declare
Index : Interp_Index;
It : Interp;
begin
Error_Msg_N ("\\possible interpretations:", N);
Get_First_Interp (Name (N), Index, It);
while Present (It.Nam) loop
Error_Msg_Sloc := Sloc (It.Nam);
Error_Msg_Node_2 := It.Nam;
Error_Msg_NE
("\\ type& for & declared#", N, It.Typ);
Get_Next_Interp (Index, It);
end loop;
end;
else
Error_Msg_N ("\use -gnatf for details", N);
end if;
else
Wrong_Type (N, Typ);
end if;
end if;
end if;
Resolution_Failed;
return;
-- Test if we have more than one interpretation for the context
elsif Ambiguous then
Resolution_Failed;
return;
-- Only one interpretation
else
-- In Ada 2005, if we have something like "X : T := 2 + 2;", where
-- the "+" on T is abstract, and the operands are of universal type,
-- the above code will have (incorrectly) resolved the "+" to the
-- universal one in Standard. Therefore check for this case and give
-- an error. We can't do this earlier, because it would cause legal
-- cases to get errors (when some other type has an abstract "+").
if Ada_Version >= Ada_2005
and then Nkind (N) in N_Op
and then Is_Overloaded (N)
and then Is_Universal_Numeric_Type (Etype (Entity (N)))
then
Get_First_Interp (N, I, It);
while Present (It.Typ) loop
if Present (It.Abstract_Op) and then
Etype (It.Abstract_Op) = Typ
then
Error_Msg_NE
("cannot call abstract subprogram &!", N, It.Abstract_Op);
return;
end if;
Get_Next_Interp (I, It);
end loop;
end if;
-- Here we have an acceptable interpretation for the context
-- Propagate type information and normalize tree for various
-- predefined operations. If the context only imposes a class of
-- types, rather than a specific type, propagate the actual type
-- downward.
if Typ = Any_Integer or else
Typ = Any_Boolean or else
Typ = Any_Modular or else
Typ = Any_Real or else
Typ = Any_Discrete
then
Ctx_Type := Expr_Type;
-- Any_Fixed is legal in a real context only if a specific fixed-
-- point type is imposed. If Norman Cohen can be confused by this,
-- it deserves a separate message.
if Typ = Any_Real
and then Expr_Type = Any_Fixed
then
Error_Msg_N ("illegal context for mixed mode operation", N);
Set_Etype (N, Universal_Real);
Ctx_Type := Universal_Real;
end if;
end if;
-- A user-defined operator is transformed into a function call at
-- this point, so that further processing knows that operators are
-- really operators (i.e. are predefined operators). User-defined
-- operators that are intrinsic are just renamings of the predefined
-- ones, and need not be turned into calls either, but if they rename
-- a different operator, we must transform the node accordingly.
-- Instantiations of Unchecked_Conversion are intrinsic but are
-- treated as functions, even if given an operator designator.
if Nkind (N) in N_Op
and then Present (Entity (N))
and then Ekind (Entity (N)) /= E_Operator
then
if not Is_Predefined_Op (Entity (N)) then
Rewrite_Operator_As_Call (N, Entity (N));
elsif Present (Alias (Entity (N)))
and then
Nkind (Parent (Parent (Entity (N)))) =
N_Subprogram_Renaming_Declaration
then
Rewrite_Renamed_Operator (N, Alias (Entity (N)), Typ);
-- If the node is rewritten, it will be fully resolved in
-- Rewrite_Renamed_Operator.
if Analyzed (N) then
return;
end if;
end if;
end if;
case N_Subexpr'(Nkind (N)) is
when N_Aggregate =>
Resolve_Aggregate (N, Ctx_Type);
when N_Allocator =>
Resolve_Allocator (N, Ctx_Type);
when N_Short_Circuit =>
Resolve_Short_Circuit (N, Ctx_Type);
when N_Attribute_Reference =>
Resolve_Attribute (N, Ctx_Type);
when N_Case_Expression =>
Resolve_Case_Expression (N, Ctx_Type);
when N_Character_Literal =>
Resolve_Character_Literal (N, Ctx_Type);
when N_Delta_Aggregate =>
Resolve_Delta_Aggregate (N, Ctx_Type);
when N_Expanded_Name =>
Resolve_Entity_Name (N, Ctx_Type);
when N_Explicit_Dereference =>
Resolve_Explicit_Dereference (N, Ctx_Type);
when N_Expression_With_Actions =>
Resolve_Expression_With_Actions (N, Ctx_Type);
when N_Extension_Aggregate =>
Resolve_Extension_Aggregate (N, Ctx_Type);
when N_Function_Call =>
Resolve_Call (N, Ctx_Type);
when N_Identifier =>
Resolve_Entity_Name (N, Ctx_Type);
when N_If_Expression =>
Resolve_If_Expression (N, Ctx_Type);
when N_Indexed_Component =>
Resolve_Indexed_Component (N, Ctx_Type);
when N_Integer_Literal =>
Resolve_Integer_Literal (N, Ctx_Type);
when N_Membership_Test =>
Resolve_Membership_Op (N, Ctx_Type);
when N_Null =>
Resolve_Null (N, Ctx_Type);
when N_Op_And
| N_Op_Or
| N_Op_Xor
=>
Resolve_Logical_Op (N, Ctx_Type);
when N_Op_Eq
| N_Op_Ne
=>
Resolve_Equality_Op (N, Ctx_Type);
when N_Op_Ge
| N_Op_Gt
| N_Op_Le
| N_Op_Lt
=>
Resolve_Comparison_Op (N, Ctx_Type);
when N_Op_Not =>
Resolve_Op_Not (N, Ctx_Type);
when N_Op_Add
| N_Op_Divide
| N_Op_Mod
| N_Op_Multiply
| N_Op_Rem
| N_Op_Subtract
=>
Resolve_Arithmetic_Op (N, Ctx_Type);
when N_Op_Concat =>
Resolve_Op_Concat (N, Ctx_Type);
when N_Op_Expon =>
Resolve_Op_Expon (N, Ctx_Type);
when N_Op_Abs
| N_Op_Minus
| N_Op_Plus
=>
Resolve_Unary_Op (N, Ctx_Type);
when N_Op_Shift =>
Resolve_Shift (N, Ctx_Type);
when N_Procedure_Call_Statement =>
Resolve_Call (N, Ctx_Type);
when N_Operator_Symbol =>
Resolve_Operator_Symbol (N, Ctx_Type);
when N_Qualified_Expression =>
Resolve_Qualified_Expression (N, Ctx_Type);
-- Why is the following null, needs a comment ???
when N_Quantified_Expression =>
null;
when N_Raise_Expression =>
Resolve_Raise_Expression (N, Ctx_Type);
when N_Raise_xxx_Error =>
Set_Etype (N, Ctx_Type);
when N_Range =>
Resolve_Range (N, Ctx_Type);
when N_Real_Literal =>
Resolve_Real_Literal (N, Ctx_Type);
when N_Reference =>
Resolve_Reference (N, Ctx_Type);
when N_Selected_Component =>
Resolve_Selected_Component (N, Ctx_Type);
when N_Slice =>
Resolve_Slice (N, Ctx_Type);
when N_String_Literal =>
Resolve_String_Literal (N, Ctx_Type);
when N_Target_Name =>
Resolve_Target_Name (N, Ctx_Type);
when N_Type_Conversion =>
Resolve_Type_Conversion (N, Ctx_Type);
when N_Unchecked_Expression =>
Resolve_Unchecked_Expression (N, Ctx_Type);
when N_Unchecked_Type_Conversion =>
Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
end case;
-- Mark relevant use-type and use-package clauses as effective using
-- the original node because constant folding may have occured and
-- removed references that need to be examined.
if Nkind (Original_Node (N)) in N_Op then
Mark_Use_Clauses (Original_Node (N));
end if;
-- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
-- expression of an anonymous access type that occurs in the context
-- of a named general access type, except when the expression is that
-- of a membership test. This ensures proper legality checking in
-- terms of allowed conversions (expressions that would be illegal to
-- convert implicitly are allowed in membership tests).
if Ada_Version >= Ada_2012
and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
and then Ekind (Etype (N)) = E_Anonymous_Access_Type
and then Nkind (Parent (N)) not in N_Membership_Test
then
Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
Analyze_And_Resolve (N, Ctx_Type);
end if;
-- If the subexpression was replaced by a non-subexpression, then
-- all we do is to expand it. The only legitimate case we know of
-- is converting procedure call statement to entry call statements,
-- but there may be others, so we are making this test general.
if Nkind (N) not in N_Subexpr then
Debug_A_Exit ("resolving ", N, " (done)");
Expand (N);
return;
end if;
-- The expression is definitely NOT overloaded at this point, so
-- we reset the Is_Overloaded flag to avoid any confusion when
-- reanalyzing the node.
Set_Is_Overloaded (N, False);
-- Freeze expression type, entity if it is a name, and designated
-- type if it is an allocator (RM 13.14(10,11,13)).
-- Now that the resolution of the type of the node is complete, and
-- we did not detect an error, we can expand this node. We skip the
-- expand call if we are in a default expression, see section
-- "Handling of Default Expressions" in Sem spec.
Debug_A_Exit ("resolving ", N, " (done)");
-- We unconditionally freeze the expression, even if we are in
-- default expression mode (the Freeze_Expression routine tests this
-- flag and only freezes static types if it is set).
-- Ada 2012 (AI05-177): The declaration of an expression function
-- does not cause freezing, but we never reach here in that case.
-- Here we are resolving the corresponding expanded body, so we do
-- need to perform normal freezing.
-- As elsewhere we do not emit freeze node within a generic. We make
-- an exception for entities that are expressions, only to detect
-- misuses of deferred constants and preserve the output of various
-- tests.
if not Inside_A_Generic or else Is_Entity_Name (N) then
Freeze_Expression (N);
end if;
-- Now we can do the expansion
Expand (N);
end if;
end Resolve;
-------------
-- Resolve --
-------------
-- Version with check(s) suppressed
procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
begin
if Suppress = All_Checks then
declare
Sva : constant Suppress_Array := Scope_Suppress.Suppress;
begin
Scope_Suppress.Suppress := (others => True);
Resolve (N, Typ);
Scope_Suppress.Suppress := Sva;
end;
else
declare
Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
begin
Scope_Suppress.Suppress (Suppress) := True;
Resolve (N, Typ);
Scope_Suppress.Suppress (Suppress) := Svg;
end;
end if;
end Resolve;
-------------
-- Resolve --
-------------
-- Version with implicit type
procedure Resolve (N : Node_Id) is
begin
Resolve (N, Etype (N));
end Resolve;
---------------------
-- Resolve_Actuals --
---------------------
procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
A : Node_Id;
A_Id : Entity_Id;
A_Typ : Entity_Id := Empty; -- init to avoid warning
F : Entity_Id;
F_Typ : Entity_Id;
Prev : Node_Id := Empty;
Orig_A : Node_Id;
Real_F : Entity_Id := Empty; -- init to avoid warning
Real_Subp : Entity_Id;
-- If the subprogram being called is an inherited operation for
-- a formal derived type in an instance, Real_Subp is the subprogram
-- that will be called. It may have different formal names than the
-- operation of the formal in the generic, so after actual is resolved
-- the name of the actual in a named association must carry the name
-- of the actual of the subprogram being called.
procedure Check_Aliased_Parameter;
-- Check rules on aliased parameters and related accessibility rules
-- in (RM 3.10.2 (10.2-10.4)).
procedure Check_Argument_Order;
-- Performs a check for the case where the actuals are all simple
-- identifiers that correspond to the formal names, but in the wrong
-- order, which is considered suspicious and cause for a warning.
procedure Check_Prefixed_Call;
-- If the original node is an overloaded call in prefix notation,
-- insert an 'Access or a dereference as needed over the first actual.
-- Try_Object_Operation has already verified that there is a valid
-- interpretation, but the form of the actual can only be determined
-- once the primitive operation is identified.
procedure Flag_Effectively_Volatile_Objects (Expr : Node_Id);
-- Emit an error concerning the illegal usage of an effectively volatile
-- object for reading in interfering context (SPARK RM 7.1.3(10)).
procedure Insert_Default;
-- If the actual is missing in a call, insert in the actuals list
-- an instance of the default expression. The insertion is always
-- a named association.
function Same_Ancestor (T1, T2 : Entity_Id) return Boolean;
-- Check whether T1 and T2, or their full views, are derived from a
-- common type. Used to enforce the restrictions on array conversions
-- of AI95-00246.
function Static_Concatenation (N : Node_Id) return Boolean;
-- Predicate to determine whether an actual that is a concatenation
-- will be evaluated statically and does not need a transient scope.
-- This must be determined before the actual is resolved and expanded
-- because if needed the transient scope must be introduced earlier.
-----------------------------
-- Check_Aliased_Parameter --
-----------------------------
procedure Check_Aliased_Parameter is
Nominal_Subt : Entity_Id;
begin
if Is_Aliased (F) then
if Is_Tagged_Type (A_Typ) then
null;
elsif Is_Aliased_View (A) then
if Is_Constr_Subt_For_U_Nominal (A_Typ) then
Nominal_Subt := Base_Type (A_Typ);
else
Nominal_Subt := A_Typ;
end if;
if Subtypes_Statically_Match (F_Typ, Nominal_Subt) then
null;
-- In a generic body assume the worst for generic formals:
-- they can have a constrained partial view (AI05-041).
elsif Has_Discriminants (F_Typ)
and then not Is_Constrained (F_Typ)
and then not Object_Type_Has_Constrained_Partial_View
(Typ => F_Typ, Scop => Current_Scope)
then
null;
else
Error_Msg_NE ("untagged actual does not statically match "
& "aliased formal&", A, F);
end if;
else
Error_Msg_NE ("actual for aliased formal& must be "
& "aliased object", A, F);
end if;
if Ekind (Nam) = E_Procedure then
null;
elsif Ekind (Etype (Nam)) = E_Anonymous_Access_Type then
if Nkind (Parent (N)) = N_Type_Conversion
and then Type_Access_Level (Etype (Parent (N)))
< Static_Accessibility_Level (A, Object_Decl_Level)
then
Error_Msg_N ("aliased actual has wrong accessibility", A);
end if;
elsif Nkind (Parent (N)) = N_Qualified_Expression
and then Nkind (Parent (Parent (N))) = N_Allocator
and then Type_Access_Level (Etype (Parent (Parent (N))))
< Static_Accessibility_Level (A, Object_Decl_Level)
then
Error_Msg_N
("aliased actual in allocator has wrong accessibility", A);
end if;
end if;
end Check_Aliased_Parameter;
--------------------------
-- Check_Argument_Order --
--------------------------
procedure Check_Argument_Order is
begin
-- Nothing to do if no parameters, or original node is neither a
-- function call nor a procedure call statement (happens in the
-- operator-transformed-to-function call case), or the call is to an
-- operator symbol (which is usually in infix form), or the call does
-- not come from source, or this warning is off.
if not Warn_On_Parameter_Order
or else No (Parameter_Associations (N))
or else Nkind (Original_Node (N)) not in N_Subprogram_Call
or else (Nkind (Name (N)) = N_Identifier
and then Present (Entity (Name (N)))
and then Nkind (Entity (Name (N))) =
N_Defining_Operator_Symbol)
or else not Comes_From_Source (N)
then
return;
end if;
declare
Nargs : constant Nat := List_Length (Parameter_Associations (N));
begin
-- Nothing to do if only one parameter
if Nargs < 2 then
return;
end if;
-- Here if at least two arguments
declare
Actuals : array (1 .. Nargs) of Node_Id;
Actual : Node_Id;
Formal : Node_Id;
Wrong_Order : Boolean := False;
-- Set True if an out of order case is found
begin
-- Collect identifier names of actuals, fail if any actual is
-- not a simple identifier, and record max length of name.
Actual := First (Parameter_Associations (N));
for J in Actuals'Range loop
if Nkind (Actual) /= N_Identifier then
return;
else
Actuals (J) := Actual;
Next (Actual);
end if;
end loop;
-- If we got this far, all actuals are identifiers and the list
-- of their names is stored in the Actuals array.
Formal := First_Formal (Nam);
for J in Actuals'Range loop
-- If we ran out of formals, that's odd, probably an error
-- which will be detected elsewhere, but abandon the search.
if No (Formal) then
return;
end if;
-- If name matches and is in order OK
if Chars (Formal) = Chars (Actuals (J)) then
null;
else
-- If no match, see if it is elsewhere in list and if so
-- flag potential wrong order if type is compatible.
for K in Actuals'Range loop
if Chars (Formal) = Chars (Actuals (K))
and then
Has_Compatible_Type (Actuals (K), Etype (Formal))
then
Wrong_Order := True;
goto Continue;
end if;
end loop;
-- No match
return;
end if;
<<Continue>> Next_Formal (Formal);
end loop;
-- If Formals left over, also probably an error, skip warning
if Present (Formal) then
return;
end if;
-- Here we give the warning if something was out of order
if Wrong_Order then
Error_Msg_N
("?P?actuals for this call may be in wrong order", N);
end if;
end;
end;
end Check_Argument_Order;
-------------------------
-- Check_Prefixed_Call --
-------------------------
procedure Check_Prefixed_Call is
Act : constant Node_Id := First_Actual (N);
A_Type : constant Entity_Id := Etype (Act);
F_Type : constant Entity_Id := Etype (First_Formal (Nam));
Orig : constant Node_Id := Original_Node (N);
New_A : Node_Id;
begin
-- Check whether the call is a prefixed call, with or without
-- additional actuals.
if Nkind (Orig) = N_Selected_Component
or else
(Nkind (Orig) = N_Indexed_Component
and then Nkind (Prefix (Orig)) = N_Selected_Component
and then Is_Entity_Name (Prefix (Prefix (Orig)))
and then Is_Entity_Name (Act)
and then Chars (Act) = Chars (Prefix (Prefix (Orig))))
then
if Is_Access_Type (A_Type)
and then not Is_Access_Type (F_Type)
then
-- Introduce dereference on object in prefix
New_A :=
Make_Explicit_Dereference (Sloc (Act),
Prefix => Relocate_Node (Act));
Rewrite (Act, New_A);
Analyze (Act);
elsif Is_Access_Type (F_Type)
and then not Is_Access_Type (A_Type)
then
-- Introduce an implicit 'Access in prefix
if not Is_Aliased_View (Act) then
Error_Msg_NE
("object in prefixed call to& must be aliased "
& "(RM 4.1.3 (13 1/2))",
Prefix (Act), Nam);
end if;
Rewrite (Act,
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Access,
Prefix => Relocate_Node (Act)));
end if;
Analyze (Act);
end if;
end Check_Prefixed_Call;
---------------------------------------
-- Flag_Effectively_Volatile_Objects --
---------------------------------------
procedure Flag_Effectively_Volatile_Objects (Expr : Node_Id) is
function Flag_Object (N : Node_Id) return Traverse_Result;
-- Determine whether arbitrary node N denotes an effectively volatile
-- object for reading and if it does, emit an error.
-----------------
-- Flag_Object --
-----------------
function Flag_Object (N : Node_Id) return Traverse_Result is
Id : Entity_Id;
begin
-- Do not consider nested function calls because they have already
-- been processed during their own resolution.
if Nkind (N) = N_Function_Call then
return Skip;
elsif Is_Entity_Name (N) and then Present (Entity (N)) then
Id := Entity (N);
if Is_Object (Id)
and then Is_Effectively_Volatile_For_Reading (Id)
then
Error_Msg_N
("volatile object cannot appear in this context (SPARK "
& "RM 7.1.3(10))", N);
return Skip;
end if;
end if;
return OK;
end Flag_Object;
procedure Flag_Objects is new Traverse_Proc (Flag_Object);
-- Start of processing for Flag_Effectively_Volatile_Objects
begin
Flag_Objects (Expr);
end Flag_Effectively_Volatile_Objects;
--------------------
-- Insert_Default --
--------------------
procedure Insert_Default is
Actval : Node_Id;
Assoc : Node_Id;
begin
-- Missing argument in call, nothing to insert
if No (Default_Value (F)) then
return;
else
-- Note that we do a full New_Copy_Tree, so that any associated
-- Itypes are properly copied. This may not be needed any more,
-- but it does no harm as a safety measure. Defaults of a generic
-- formal may be out of bounds of the corresponding actual (see
-- cc1311b) and an additional check may be required.
Actval :=
New_Copy_Tree
(Default_Value (F),
New_Scope => Current_Scope,
New_Sloc => Loc);
-- Propagate dimension information, if any.
Copy_Dimensions (Default_Value (F), Actval);
if Is_Concurrent_Type (Scope (Nam))
and then Has_Discriminants (Scope (Nam))
then
Replace_Actual_Discriminants (N, Actval);
end if;
if Is_Overloadable (Nam)
and then Present (Alias (Nam))
then
if Base_Type (Etype (F)) /= Base_Type (Etype (Actval))
and then not Is_Tagged_Type (Etype (F))
then
-- If default is a real literal, do not introduce a
-- conversion whose effect may depend on the run-time
-- size of universal real.
if Nkind (Actval) = N_Real_Literal then
Set_Etype (Actval, Base_Type (Etype (F)));
else
Actval := Unchecked_Convert_To (Etype (F), Actval);
end if;
end if;
if Is_Scalar_Type (Etype (F)) then
Enable_Range_Check (Actval);
end if;
Set_Parent (Actval, N);
-- Resolve aggregates with their base type, to avoid scope
-- anomalies: the subtype was first built in the subprogram
-- declaration, and the current call may be nested.
if Nkind (Actval) = N_Aggregate then
Analyze_And_Resolve (Actval, Etype (F));
else
Analyze_And_Resolve (Actval, Etype (Actval));
end if;
else
Set_Parent (Actval, N);
-- See note above concerning aggregates
if Nkind (Actval) = N_Aggregate
and then Has_Discriminants (Etype (Actval))
then
Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
-- Resolve entities with their own type, which may differ from
-- the type of a reference in a generic context (the view
-- swapping mechanism did not anticipate the re-analysis of
-- default values in calls).
elsif Is_Entity_Name (Actval) then
Analyze_And_Resolve (Actval, Etype (Entity (Actval)));
else
Analyze_And_Resolve (Actval, Etype (Actval));
end if;
end if;
-- If default is a tag indeterminate function call, propagate tag
-- to obtain proper dispatching.
if Is_Controlling_Formal (F)
and then Nkind (Default_Value (F)) = N_Function_Call
then
Set_Is_Controlling_Actual (Actval);
end if;
end if;
-- If the default expression raises constraint error, then just
-- silently replace it with an N_Raise_Constraint_Error node, since
-- we already gave the warning on the subprogram spec. If node is
-- already a Raise_Constraint_Error leave as is, to prevent loops in
-- the warnings removal machinery.
if Raises_Constraint_Error (Actval)
and then Nkind (Actval) /= N_Raise_Constraint_Error
then
Rewrite (Actval,
Make_Raise_Constraint_Error (Loc,
Reason => CE_Range_Check_Failed));
Set_Raises_Constraint_Error (Actval);
Set_Etype (Actval, Etype (F));
end if;
Assoc :=
Make_Parameter_Association (Loc,
Explicit_Actual_Parameter => Actval,
Selector_Name => Make_Identifier (Loc, Chars (F)));
-- Case of insertion is first named actual
if No (Prev)
or else Nkind (Parent (Prev)) /= N_Parameter_Association
then
Set_Next_Named_Actual (Assoc, First_Named_Actual (N));
Set_First_Named_Actual (N, Actval);
if No (Prev) then
if No (Parameter_Associations (N)) then
Set_Parameter_Associations (N, New_List (Assoc));
else
Append (Assoc, Parameter_Associations (N));
end if;
else
Insert_After (Prev, Assoc);
end if;
-- Case of insertion is not first named actual
else
Set_Next_Named_Actual
(Assoc, Next_Named_Actual (Parent (Prev)));
Set_Next_Named_Actual (Parent (Prev), Actval);
Append (Assoc, Parameter_Associations (N));
end if;
Mark_Rewrite_Insertion (Assoc);
Mark_Rewrite_Insertion (Actval);
Prev := Actval;
end Insert_Default;
-------------------
-- Same_Ancestor --
-------------------
function Same_Ancestor (T1, T2 : Entity_Id) return Boolean is
FT1 : Entity_Id := T1;
FT2 : Entity_Id := T2;
begin
if Is_Private_Type (T1)
and then Present (Full_View (T1))
then
FT1 := Full_View (T1);
end if;
if Is_Private_Type (T2)
and then Present (Full_View (T2))
then
FT2 := Full_View (T2);
end if;
return Root_Type (Base_Type (FT1)) = Root_Type (Base_Type (FT2));
end Same_Ancestor;
--------------------------
-- Static_Concatenation --
--------------------------
function Static_Concatenation (N : Node_Id) return Boolean is
begin
case Nkind (N) is
when N_String_Literal =>
return True;
when N_Op_Concat =>
-- Concatenation is static when both operands are static and
-- the concatenation operator is a predefined one.
return Scope (Entity (N)) = Standard_Standard
and then
Static_Concatenation (Left_Opnd (N))
and then
Static_Concatenation (Right_Opnd (N));
when others =>
if Is_Entity_Name (N) then
declare
Ent : constant Entity_Id := Entity (N);
begin
return Ekind (Ent) = E_Constant
and then Present (Constant_Value (Ent))
and then
Is_OK_Static_Expression (Constant_Value (Ent));
end;
else
return False;
end if;
end case;
end Static_Concatenation;
-- Start of processing for Resolve_Actuals
begin
Check_Argument_Order;
if Is_Overloadable (Nam)
and then Is_Inherited_Operation (Nam)
and then In_Instance
and then Present (Alias (Nam))
and then Present (Overridden_Operation (Alias (Nam)))
then
Real_Subp := Alias (Nam);
else
Real_Subp := Empty;
end if;
if Present (First_Actual (N)) then
Check_Prefixed_Call;
end if;
A := First_Actual (N);
F := First_Formal (Nam);
if Present (Real_Subp) then
Real_F := First_Formal (Real_Subp);
end if;
while Present (F) loop
if No (A) and then Needs_No_Actuals (Nam) then
null;
-- If we have an error in any actual or formal, indicated by a type
-- of Any_Type, then abandon resolution attempt, and set result type
-- to Any_Type. Skip this if the actual is a Raise_Expression, whose
-- type is imposed from context.
elsif (Present (A) and then Etype (A) = Any_Type)
or else Etype (F) = Any_Type
then
if Nkind (A) /= N_Raise_Expression then
Set_Etype (N, Any_Type);
return;
end if;
end if;
-- Case where actual is present
-- If the actual is an entity, generate a reference to it now. We
-- do this before the actual is resolved, because a formal of some
-- protected subprogram, or a task discriminant, will be rewritten
-- during expansion, and the source entity reference may be lost.
if Present (A)
and then Is_Entity_Name (A)
and then Comes_From_Source (A)
then
-- Annotate the tree by creating a variable reference marker when
-- the actual denotes a variable reference, in case the reference
-- is folded or optimized away. The variable reference marker is
-- automatically saved for later examination by the ABE Processing
-- phase. The status of the reference is set as follows:
-- status mode
-- read IN, IN OUT
-- write IN OUT, OUT
if Needs_Variable_Reference_Marker
(N => A,
Calls_OK => True)
then
Build_Variable_Reference_Marker
(N => A,
Read => Ekind (F) /= E_Out_Parameter,
Write => Ekind (F) /= E_In_Parameter);
end if;
Orig_A := Entity (A);
if Present (Orig_A) then
if Is_Formal (Orig_A)
and then Ekind (F) /= E_In_Parameter
then
Generate_Reference (Orig_A, A, 'm');
elsif not Is_Overloaded (A) then
if Ekind (F) /= E_Out_Parameter then
Generate_Reference (Orig_A, A);
-- RM 6.4.1(12): For an out parameter that is passed by
-- copy, the formal parameter object is created, and:
-- * For an access type, the formal parameter is initialized
-- from the value of the actual, without checking that the
-- value satisfies any constraint, any predicate, or any
-- exclusion of the null value.
-- * For a scalar type that has the Default_Value aspect
-- specified, the formal parameter is initialized from the
-- value of the actual, without checking that the value
-- satisfies any constraint or any predicate.
-- I do not understand why this case is included??? this is
-- not a case where an OUT parameter is treated as IN OUT.
-- * For a composite type with discriminants or that has
-- implicit initial values for any subcomponents, the
-- behavior is as for an in out parameter passed by copy.
-- Hence for these cases we generate the read reference now
-- (the write reference will be generated later by
-- Note_Possible_Modification).
elsif Is_By_Copy_Type (Etype (F))
and then
(Is_Access_Type (Etype (F))
or else
(Is_Scalar_Type (Etype (F))
and then
Present (Default_Aspect_Value (Etype (F))))
or else
(Is_Composite_Type (Etype (F))
and then (Has_Discriminants (Etype (F))
or else Is_Partially_Initialized_Type
(Etype (F)))))
then
Generate_Reference (Orig_A, A);
end if;
end if;
end if;
end if;
if Present (A)
and then (Nkind (Parent (A)) /= N_Parameter_Association
or else Chars (Selector_Name (Parent (A))) = Chars (F))
then
-- If style checking mode on, check match of formal name
if Style_Check then
if Nkind (Parent (A)) = N_Parameter_Association then
Check_Identifier (Selector_Name (Parent (A)), F);
end if;
end if;
-- If the formal is Out or In_Out, do not resolve and expand the
-- conversion, because it is subsequently expanded into explicit
-- temporaries and assignments. However, the object of the
-- conversion can be resolved. An exception is the case of tagged
-- type conversion with a class-wide actual. In that case we want
-- the tag check to occur and no temporary will be needed (no
-- representation change can occur) and the parameter is passed by
-- reference, so we go ahead and resolve the type conversion.
-- Another exception is the case of reference to component or
-- subcomponent of a bit-packed array, in which case we want to
-- defer expansion to the point the in and out assignments are
-- performed.
if Ekind (F) /= E_In_Parameter
and then Nkind (A) = N_Type_Conversion
and then not Is_Class_Wide_Type (Etype (Expression (A)))
and then not Is_Interface (Etype (A))
then
declare
Expr_Typ : constant Entity_Id := Etype (Expression (A));
begin
-- Check RM 4.6 (24.2/2)
if Is_Array_Type (Etype (F))
and then Is_View_Conversion (A)
then
-- In a view conversion, the conversion must be legal in
-- both directions, and thus both component types must be
-- aliased, or neither (4.6 (8)).
-- Check RM 4.6 (24.8/2)
if Has_Aliased_Components (Expr_Typ) /=
Has_Aliased_Components (Etype (F))
then
-- This normally illegal conversion is legal in an
-- expanded instance body because of RM 12.3(11).
-- At runtime, conversion must create a new object.
if not In_Instance then
Error_Msg_N
("both component types in a view conversion must"
& " be aliased, or neither", A);
end if;
-- Check RM 4.6 (24/3)
elsif not Same_Ancestor (Etype (F), Expr_Typ) then
-- Check view conv between unrelated by ref array
-- types.
if Is_By_Reference_Type (Etype (F))
or else Is_By_Reference_Type (Expr_Typ)
then
Error_Msg_N
("view conversion between unrelated by reference "
& "array types not allowed ('A'I-00246)", A);
-- In Ada 2005 mode, check view conversion component
-- type cannot be private, tagged, or volatile. Note
-- that we only apply this to source conversions. The
-- generated code can contain conversions which are
-- not subject to this test, and we cannot extract the
-- component type in such cases since it is not
-- present.
elsif Comes_From_Source (A)
and then Ada_Version >= Ada_2005
then
declare
Comp_Type : constant Entity_Id :=
Component_Type (Expr_Typ);
begin
if (Is_Private_Type (Comp_Type)
and then not Is_Generic_Type (Comp_Type))
or else Is_Tagged_Type (Comp_Type)
or else Is_Volatile (Comp_Type)
then
Error_Msg_N
("component type of a view conversion " &
"cannot be private, tagged, or volatile" &
" (RM 4.6 (24))",
Expression (A));
end if;
end;
end if;
end if;
-- AI12-0074 & AI12-0377
-- Check 6.4.1: If the mode is out, the actual parameter is
-- a view conversion, and the type of the formal parameter
-- is a scalar type, then either:
-- - the target and operand type both do not have the
-- Default_Value aspect specified; or
-- - the target and operand type both have the
-- Default_Value aspect specified, and there shall exist
-- a type (other than a root numeric type) that is an
-- ancestor of both the target type and the operand
-- type.
elsif Ekind (F) = E_Out_Parameter
and then Is_Scalar_Type (Etype (F))
then
if Has_Default_Aspect (Etype (F)) /=
Has_Default_Aspect (Expr_Typ)
then
Error_Msg_N
("view conversion requires Default_Value on both " &
"types (RM 6.4.1)", A);
elsif Has_Default_Aspect (Expr_Typ)
and then not Same_Ancestor (Etype (F), Expr_Typ)
then
Error_Msg_N
("view conversion between unrelated types with "
& "Default_Value not allowed (RM 6.4.1)", A);
end if;
end if;
end;
-- Resolve expression if conversion is all OK
if (Conversion_OK (A)
or else Valid_Conversion (A, Etype (A), Expression (A)))
and then not Is_Ref_To_Bit_Packed_Array (Expression (A))
then
Resolve (Expression (A));
end if;
-- If the actual is a function call that returns a limited
-- unconstrained object that needs finalization, create a
-- transient scope for it, so that it can receive the proper
-- finalization list.
elsif Expander_Active
and then Nkind (A) = N_Function_Call
and then Is_Limited_Record (Etype (F))
and then not Is_Constrained (Etype (F))
and then (Needs_Finalization (Etype (F))
or else Has_Task (Etype (F)))
then
Establish_Transient_Scope (A, Manage_Sec_Stack => False);
Resolve (A, Etype (F));
-- A small optimization: if one of the actuals is a concatenation
-- create a block around a procedure call to recover stack space.
-- This alleviates stack usage when several procedure calls in
-- the same statement list use concatenation. We do not perform
-- this wrapping for code statements, where the argument is a
-- static string, and we want to preserve warnings involving
-- sequences of such statements.
elsif Expander_Active
and then Nkind (A) = N_Op_Concat
and then Nkind (N) = N_Procedure_Call_Statement
and then not (Is_Intrinsic_Subprogram (Nam)
and then Chars (Nam) = Name_Asm)
and then not Static_Concatenation (A)
then
Establish_Transient_Scope (A, Manage_Sec_Stack => False);
Resolve (A, Etype (F));
else
if Nkind (A) = N_Type_Conversion
and then Is_Array_Type (Etype (F))
and then not Same_Ancestor (Etype (F), Etype (Expression (A)))
and then
(Is_Limited_Type (Etype (F))
or else Is_Limited_Type (Etype (Expression (A))))
then
Error_Msg_N
("conversion between unrelated limited array types not "
& "allowed ('A'I-00246)", A);
if Is_Limited_Type (Etype (F)) then
Explain_Limited_Type (Etype (F), A);
end if;
if Is_Limited_Type (Etype (Expression (A))) then
Explain_Limited_Type (Etype (Expression (A)), A);
end if;
end if;
-- (Ada 2005: AI-251): If the actual is an allocator whose
-- directly designated type is a class-wide interface, we build
-- an anonymous access type to use it as the type of the
-- allocator. Later, when the subprogram call is expanded, if
-- the interface has a secondary dispatch table the expander
-- will add a type conversion to force the correct displacement
-- of the pointer.
if Nkind (A) = N_Allocator then
declare
DDT : constant Entity_Id :=
Directly_Designated_Type (Base_Type (Etype (F)));
begin
-- Displace the pointer to the object to reference its
-- secondary dispatch table.
if Is_Class_Wide_Type (DDT)
and then Is_Interface (DDT)
then
Rewrite (A, Convert_To (Etype (F), Relocate_Node (A)));
Analyze_And_Resolve (A, Etype (F),
Suppress => Access_Check);
end if;
-- Ada 2005, AI-162:If the actual is an allocator, the
-- innermost enclosing statement is the master of the
-- created object. This needs to be done with expansion
-- enabled only, otherwise the transient scope will not
-- be removed in the expansion of the wrapped construct.
if Expander_Active
and then (Needs_Finalization (DDT)
or else Has_Task (DDT))
then
Establish_Transient_Scope
(A, Manage_Sec_Stack => False);
end if;
end;
if Ekind (Etype (F)) = E_Anonymous_Access_Type then
Check_Restriction (No_Access_Parameter_Allocators, A);
end if;
end if;
-- (Ada 2005): The call may be to a primitive operation of a
-- tagged synchronized type, declared outside of the type. In
-- this case the controlling actual must be converted to its
-- corresponding record type, which is the formal type. The
-- actual may be a subtype, either because of a constraint or
-- because it is a generic actual, so use base type to locate
-- concurrent type.
F_Typ := Base_Type (Etype (F));
if Is_Tagged_Type (F_Typ)
and then (Is_Concurrent_Type (F_Typ)
or else Is_Concurrent_Record_Type (F_Typ))
then
-- If the actual is overloaded, look for an interpretation
-- that has a synchronized type.
if not Is_Overloaded (A) then
A_Typ := Base_Type (Etype (A));
else
declare
Index : Interp_Index;
It : Interp;
begin
Get_First_Interp (A, Index, It);
while Present (It.Typ) loop
if Is_Concurrent_Type (It.Typ)
or else Is_Concurrent_Record_Type (It.Typ)
then
A_Typ := Base_Type (It.Typ);
exit;
end if;
Get_Next_Interp (Index, It);
end loop;
end;
end if;
declare
Full_A_Typ : Entity_Id;
begin
if Present (Full_View (A_Typ)) then
Full_A_Typ := Base_Type (Full_View (A_Typ));
else
Full_A_Typ := A_Typ;
end if;
-- Tagged synchronized type (case 1): the actual is a
-- concurrent type.
if Is_Concurrent_Type (A_Typ)
and then Corresponding_Record_Type (A_Typ) = F_Typ
then
Rewrite (A,
Unchecked_Convert_To
(Corresponding_Record_Type (A_Typ), A));
Resolve (A, Etype (F));
-- Tagged synchronized type (case 2): the formal is a
-- concurrent type.
elsif Ekind (Full_A_Typ) = E_Record_Type
and then Present
(Corresponding_Concurrent_Type (Full_A_Typ))
and then Is_Concurrent_Type (F_Typ)
and then Present (Corresponding_Record_Type (F_Typ))
and then Full_A_Typ = Corresponding_Record_Type (F_Typ)
then
Resolve (A, Corresponding_Record_Type (F_Typ));
-- Common case
else
Resolve (A, Etype (F));
end if;
end;
-- Not a synchronized operation
else
Resolve (A, Etype (F));
end if;
end if;
A_Typ := Etype (A);
F_Typ := Etype (F);
-- An actual cannot be an untagged formal incomplete type
if Ekind (A_Typ) = E_Incomplete_Type
and then not Is_Tagged_Type (A_Typ)
and then Is_Generic_Type (A_Typ)
then
Error_Msg_N
("invalid use of untagged formal incomplete type", A);
end if;
-- has warnings suppressed, then we reset Never_Set_In_Source for
-- the calling entity. The reason for this is to catch cases like
-- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
-- uses trickery to modify an IN parameter.
if Ekind (F) = E_In_Parameter
and then Is_Entity_Name (A)
and then Present (Entity (A))
and then Ekind (Entity (A)) = E_Variable
and then Has_Warnings_Off (F_Typ)
then
Set_Never_Set_In_Source (Entity (A), False);
end if;
-- Perform error checks for IN and IN OUT parameters
if Ekind (F) /= E_Out_Parameter then
-- Check unset reference. For scalar parameters, it is clearly
-- wrong to pass an uninitialized value as either an IN or
-- IN-OUT parameter. For composites, it is also clearly an
-- error to pass a completely uninitialized value as an IN
-- parameter, but the case of IN OUT is trickier. We prefer
-- not to give a warning here. For example, suppose there is
-- a routine that sets some component of a record to False.
-- It is perfectly reasonable to make this IN-OUT and allow
-- either initialized or uninitialized records to be passed
-- in this case.
-- For partially initialized composite values, we also avoid
-- warnings, since it is quite likely that we are passing a
-- partially initialized value and only the initialized fields
-- will in fact be read in the subprogram.
if Is_Scalar_Type (A_Typ)
or else (Ekind (F) = E_In_Parameter
and then not Is_Partially_Initialized_Type (A_Typ))
then
Check_Unset_Reference (A);
end if;
-- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
-- actual to a nested call, since this constitutes a reading of
-- the parameter, which is not allowed.
if Ada_Version = Ada_83
and then Is_Entity_Name (A)
and then Ekind (Entity (A)) = E_Out_Parameter
then
Error_Msg_N ("(Ada 83) illegal reading of out parameter", A);
end if;
end if;
-- In -gnatd.q mode, forget that a given array is constant when
-- it is passed as an IN parameter to a foreign-convention
-- subprogram. This is in case the subprogram evilly modifies the
-- object. Of course, correct code would use IN OUT.
if Debug_Flag_Dot_Q
and then Ekind (F) = E_In_Parameter
and then Has_Foreign_Convention (Nam)
and then Is_Array_Type (F_Typ)
and then Nkind (A) in N_Has_Entity
and then Present (Entity (A))
then
Set_Is_True_Constant (Entity (A), False);
end if;
-- Case of OUT or IN OUT parameter
if Ekind (F) /= E_In_Parameter then
-- For an Out parameter, check for useless assignment. Note
-- that we can't set Last_Assignment this early, because we may
-- kill current values in Resolve_Call, and that call would
-- clobber the Last_Assignment field.
-- Note: call Warn_On_Useless_Assignment before doing the check
-- below for Is_OK_Variable_For_Out_Formal so that the setting
-- of Referenced_As_LHS/Referenced_As_Out_Formal properly
-- reflects the last assignment, not this one.
if Ekind (F) = E_Out_Parameter then
if Warn_On_Modified_As_Out_Parameter (F)
and then Is_Entity_Name (A)
and then Present (Entity (A))
and then Comes_From_Source (N)
then
Warn_On_Useless_Assignment (Entity (A), A);
end if;
end if;
-- Validate the form of the actual. Note that the call to
-- Is_OK_Variable_For_Out_Formal generates the required
-- reference in this case.
-- A call to an initialization procedure for an aggregate
-- component may initialize a nested component of a constant
-- designated object. In this context the object is variable.
if not Is_OK_Variable_For_Out_Formal (A)
and then not Is_Init_Proc (Nam)
then
Error_Msg_NE ("actual for& must be a variable", A, F);
if Is_Subprogram (Current_Scope) then
if Is_Invariant_Procedure (Current_Scope)
or else Is_Partial_Invariant_Procedure (Current_Scope)
then
Error_Msg_N
("function used in invariant cannot modify its "
& "argument", F);
elsif Is_Predicate_Function (Current_Scope) then
Error_Msg_N
("function used in predicate cannot modify its "
& "argument", F);
end if;
end if;
end if;
-- What's the following about???
if Is_Entity_Name (A) then
Kill_Checks (Entity (A));
else
Kill_All_Checks;
end if;
end if;
if A_Typ = Any_Type then
Set_Etype (N, Any_Type);
return;
end if;
-- Apply appropriate constraint/predicate checks for IN [OUT] case
if Ekind (F) in E_In_Parameter | E_In_Out_Parameter then
-- Apply predicate tests except in certain special cases. Note
-- that it might be more consistent to apply these only when
-- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
-- for the outbound predicate tests ??? In any case indicate
-- the function being called, for better warnings if the call
-- leads to an infinite recursion.
if Predicate_Tests_On_Arguments (Nam) then
Apply_Predicate_Check (A, F_Typ, Nam);
end if;
-- Apply required constraint checks
if Is_Scalar_Type (A_Typ) then
Apply_Scalar_Range_Check (A, F_Typ);
elsif Is_Array_Type (A_Typ) then
Apply_Length_Check (A, F_Typ);
elsif Is_Record_Type (F_Typ)
and then Has_Discriminants (F_Typ)
and then Is_Constrained (F_Typ)
and then (not Is_Derived_Type (F_Typ)
or else Comes_From_Source (Nam))
then
Apply_Discriminant_Check (A, F_Typ);
-- For view conversions of a discriminated object, apply
-- check to object itself, the conversion alreay has the
-- proper type.
if Nkind (A) = N_Type_Conversion
and then Is_Constrained (Etype (Expression (A)))
then
Apply_Discriminant_Check (Expression (A), F_Typ);
end if;
elsif Is_Access_Type (F_Typ)
and then Is_Array_Type (Designated_Type (F_Typ))
and then Is_Constrained (Designated_Type (F_Typ))
then
Apply_Length_Check (A, F_Typ);
elsif Is_Access_Type (F_Typ)
and then Has_Discriminants (Designated_Type (F_Typ))
and then Is_Constrained (Designated_Type (F_Typ))
then
Apply_Discriminant_Check (A, F_Typ);
else
Apply_Range_Check (A, F_Typ);
end if;
-- Ada 2005 (AI-231): Note that the controlling parameter case
-- already existed in Ada 95, which is partially checked
-- elsewhere (see Checks), and we don't want the warning
-- message to differ.
if Is_Access_Type (F_Typ)
and then Can_Never_Be_Null (F_Typ)
and then Known_Null (A)
then
if Is_Controlling_Formal (F) then
Apply_Compile_Time_Constraint_Error
(N => A,
Msg => "null value not allowed here??",
Reason => CE_Access_Check_Failed);
elsif Ada_Version >= Ada_2005 then
Apply_Compile_Time_Constraint_Error
(N => A,
Msg => "(Ada 2005) NULL not allowed in "
& "null-excluding formal??",
Reason => CE_Null_Not_Allowed);
end if;
end if;
end if;
-- Checks for OUT parameters and IN OUT parameters
if Ekind (F) in E_Out_Parameter | E_In_Out_Parameter then
-- If there is a type conversion, make sure the return value
-- meets the constraints of the variable before the conversion.
if Nkind (A) = N_Type_Conversion then
if Is_Scalar_Type (A_Typ) then
-- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
-- which would prevent the check from being generated.
-- This is for Starlet only though, so long obsolete.
if Mechanism (F) = By_Reference
and then Ekind (Nam) = E_Procedure
and then Is_Valued_Procedure (Nam)
then
null;
else
Apply_Scalar_Range_Check
(Expression (A), Etype (Expression (A)), A_Typ);
end if;
-- In addition the return value must meet the constraints
-- of the object type (see the comment below).
Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
else
Apply_Range_Check
(Expression (A), Etype (Expression (A)), A_Typ);
end if;
-- If no conversion, apply scalar range checks and length check
-- based on the subtype of the actual (NOT that of the formal).
-- This indicates that the check takes place on return from the
-- call. During expansion the required constraint checks are
-- inserted. In GNATprove mode, in the absence of expansion,
-- the flag indicates that the returned value is valid.
else
if Is_Scalar_Type (F_Typ) then
Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
elsif Is_Array_Type (F_Typ)
and then Ekind (F) = E_Out_Parameter
then
Apply_Length_Check (A, F_Typ);
else
Apply_Range_Check (A, A_Typ, F_Typ);
end if;
end if;
-- Note: we do not apply the predicate checks for the case of
-- OUT and IN OUT parameters. They are instead applied in the
-- Expand_Actuals routine in Exp_Ch6.
end if;
-- An actual associated with an access parameter is implicitly
-- converted to the anonymous access type of the formal and must
-- satisfy the legality checks for access conversions.
if Ekind (F_Typ) = E_Anonymous_Access_Type then
if not Valid_Conversion (A, F_Typ, A) then
Error_Msg_N
("invalid implicit conversion for access parameter", A);
end if;
-- If the actual is an access selected component of a variable,
-- the call may modify its designated object. It is reasonable
-- to treat this as a potential modification of the enclosing
-- record, to prevent spurious warnings that it should be
-- declared as a constant, because intuitively programmers
-- regard the designated subcomponent as part of the record.
if Nkind (A) = N_Selected_Component
and then Is_Entity_Name (Prefix (A))
and then not Is_Constant_Object (Entity (Prefix (A)))
then
Note_Possible_Modification (A, Sure => False);
end if;
end if;
-- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
if (Is_By_Reference_Type (Etype (F)) or else Is_Aliased (F))
and then Comes_From_Source (N)
then
if Is_Atomic_Object (A)
and then not Is_Atomic (Etype (F))
then
Error_Msg_NE
("cannot pass atomic object to nonatomic formal&",
A, F);
Error_Msg_N
("\which is passed by reference (RM C.6(12))", A);
elsif Is_Volatile_Object (A)
and then not Is_Volatile (Etype (F))
then
Error_Msg_NE
("cannot pass volatile object to nonvolatile formal&",
A, F);
Error_Msg_N
("\which is passed by reference (RM C.6(12))", A);
elsif Is_Volatile_Full_Access_Object (A)
and then not Is_Volatile_Full_Access (Etype (F))
then
Error_Msg_NE
("cannot pass full access object to nonfull access "
& "formal&", A, F);
Error_Msg_N
("\which is passed by reference (RM C.6(12))", A);
end if;
-- Check for nonatomic subcomponent of a full access object
-- in Ada 2020 (RM C.6 (12)).
if Ada_Version >= Ada_2020
and then Is_Subcomponent_Of_Full_Access_Object (A)
and then not Is_Atomic_Object (A)
then
Error_Msg_N
("cannot pass nonatomic subcomponent of full access "
& "object", A);
Error_Msg_NE
("\to formal & which is passed by reference (RM C.6(12))",
A, F);
end if;
end if;
-- Check that subprograms don't have improper controlling
-- arguments (RM 3.9.2 (9)).
-- A primitive operation may have an access parameter of an
-- incomplete tagged type, but a dispatching call is illegal
-- if the type is still incomplete.
if Is_Controlling_Formal (F) then
Set_Is_Controlling_Actual (A);
if Ekind (Etype (F)) = E_Anonymous_Access_Type then
declare
Desig : constant Entity_Id := Designated_Type (Etype (F));
begin
if Ekind (Desig) = E_Incomplete_Type
and then No (Full_View (Desig))
and then No (Non_Limited_View (Desig))
then
Error_Msg_NE
("premature use of incomplete type& "
& "in dispatching call", A, Desig);
end if;
end;
end if;
elsif Nkind (A) = N_Explicit_Dereference then
Validate_Remote_Access_To_Class_Wide_Type (A);
end if;
-- Apply legality rule 3.9.2 (9/1)
if (Is_Class_Wide_Type (A_Typ) or else Is_Dynamically_Tagged (A))
and then not Is_Class_Wide_Type (F_Typ)
and then not Is_Controlling_Formal (F)
and then not In_Instance
then
Error_Msg_N ("class-wide argument not allowed here!", A);
if Is_Subprogram (Nam) and then Comes_From_Source (Nam) then
Error_Msg_Node_2 := F_Typ;
Error_Msg_NE
("& is not a dispatching operation of &!", A, Nam);
end if;
-- Apply the checks described in 3.10.2(27): if the context is a
-- specific access-to-object, the actual cannot be class-wide.
-- Use base type to exclude access_to_subprogram cases.
elsif Is_Access_Type (A_Typ)
and then Is_Access_Type (F_Typ)
and then not Is_Access_Subprogram_Type (Base_Type (F_Typ))
and then (Is_Class_Wide_Type (Designated_Type (A_Typ))
or else (Nkind (A) = N_Attribute_Reference
and then
Is_Class_Wide_Type (Etype (Prefix (A)))))
and then not Is_Class_Wide_Type (Designated_Type (F_Typ))
and then not Is_Controlling_Formal (F)
-- Disable these checks for call to imported C++ subprograms
and then not
(Is_Entity_Name (Name (N))
and then Is_Imported (Entity (Name (N)))
and then Convention (Entity (Name (N))) = Convention_CPP)
then
Error_Msg_N
("access to class-wide argument not allowed here!", A);
if Is_Subprogram (Nam) and then Comes_From_Source (Nam) then
Error_Msg_Node_2 := Designated_Type (F_Typ);
Error_Msg_NE
("& is not a dispatching operation of &!", A, Nam);
end if;
end if;
Check_Aliased_Parameter;
Eval_Actual (A);
-- If it is a named association, treat the selector_name as a
-- proper identifier, and mark the corresponding entity.
if Nkind (Parent (A)) = N_Parameter_Association
-- Ignore reference in SPARK mode, as it refers to an entity not
-- in scope at the point of reference, so the reference should
-- be ignored for computing effects of subprograms.
and then not GNATprove_Mode
then
-- If subprogram is overridden, use name of formal that
-- is being called.
if Present (Real_Subp) then
Set_Entity (Selector_Name (Parent (A)), Real_F);
Set_Etype (Selector_Name (Parent (A)), Etype (Real_F));
else
Set_Entity (Selector_Name (Parent (A)), F);
Generate_Reference (F, Selector_Name (Parent (A)));
Set_Etype (Selector_Name (Parent (A)), F_Typ);
Generate_Reference (F_Typ, N, ' ');
end if;
end if;
Prev := A;
if Ekind (F) /= E_Out_Parameter then
Check_Unset_Reference (A);
end if;
-- The following checks are only relevant when SPARK_Mode is on as
-- they are not standard Ada legality rule. Internally generated
-- temporaries are ignored.
if SPARK_Mode = On and then Comes_From_Source (A) then
-- An effectively volatile object for reading may act as an
-- actual when the corresponding formal is of a non-scalar
-- effectively volatile type for reading (SPARK RM 7.1.3(10)).
if not Is_Scalar_Type (Etype (F))
and then Is_Effectively_Volatile_For_Reading (Etype (F))
then
null;
-- An effectively volatile object for reading may act as an
-- actual in a call to an instance of Unchecked_Conversion.
-- (SPARK RM 7.1.3(10)).
elsif Is_Unchecked_Conversion_Instance (Nam) then
null;
-- The actual denotes an object
elsif Is_Effectively_Volatile_Object_For_Reading (A) then
Error_Msg_N
("volatile object cannot act as actual in a call (SPARK "
& "RM 7.1.3(10))", A);
-- Otherwise the actual denotes an expression. Inspect the
-- expression and flag each effectively volatile object
-- for reading as illegal because it apprears within an
-- interfering context. Note that this is usually done in
-- Resolve_Entity_Name, but when the effectively volatile
-- object for reading appears as an actual in a call, the
-- call must be resolved first.
else
Flag_Effectively_Volatile_Objects (A);
end if;
-- An effectively volatile variable cannot act as an actual
-- parameter in a procedure call when the variable has enabled
-- property Effective_Reads and the corresponding formal is of
-- mode IN (SPARK RM 7.1.3(10)).
if Ekind (Nam) = E_Procedure
and then Ekind (F) = E_In_Parameter
and then Is_Entity_Name (A)
then
A_Id := Entity (A);
if Ekind (A_Id) = E_Variable
and then Is_Effectively_Volatile_For_Reading (Etype (A_Id))
and then Effective_Reads_Enabled (A_Id)
then
Error_Msg_NE
("effectively volatile variable & cannot appear as "
& "actual in procedure call", A, A_Id);
Error_Msg_Name_1 := Name_Effective_Reads;
Error_Msg_N ("\\variable has enabled property %", A);
Error_Msg_N ("\\corresponding formal has mode IN", A);
end if;
end if;
end if;
-- A formal parameter of a specific tagged type whose related
-- subprogram is subject to pragma Extensions_Visible with value
-- "False" cannot act as an actual in a subprogram with value
-- "True" (SPARK RM 6.1.7(3)).
if Is_EVF_Expression (A)
and then Extensions_Visible_Status (Nam) =
Extensions_Visible_True
then
Error_Msg_N
("formal parameter cannot act as actual parameter when "
& "Extensions_Visible is False", A);
Error_Msg_NE
("\subprogram & has Extensions_Visible True", A, Nam);
end if;
-- The actual parameter of a Ghost subprogram whose formal is of
-- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
if Comes_From_Source (Nam)
and then Is_Ghost_Entity (Nam)
and then Ekind (F) in E_In_Out_Parameter | E_Out_Parameter
and then Is_Entity_Name (A)
and then Present (Entity (A))
and then not Is_Ghost_Entity (Entity (A))
then
Error_Msg_NE
("non-ghost variable & cannot appear as actual in call to "
& "ghost procedure", A, Entity (A));
if Ekind (F) = E_In_Out_Parameter then
Error_Msg_N ("\corresponding formal has mode `IN OUT`", A);
else
Error_Msg_N ("\corresponding formal has mode OUT", A);
end if;
end if;
Next_Actual (A);
-- Case where actual is not present
else
Insert_Default;
end if;
Next_Formal (F);
if Present (Real_Subp) then
Next_Formal (Real_F);
end if;
end loop;
end Resolve_Actuals;
-----------------------
-- Resolve_Allocator --
-----------------------
procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id) is
Desig_T : constant Entity_Id := Designated_Type (Typ);
E : constant Node_Id := Expression (N);
Subtyp : Entity_Id;
Discrim : Entity_Id;
Constr : Node_Id;
Aggr : Node_Id;
Assoc : Node_Id := Empty;
Disc_Exp : Node_Id;
procedure Check_Allocator_Discrim_Accessibility
(Disc_Exp : Node_Id;
Alloc_Typ : Entity_Id);
-- Check that accessibility level associated with an access discriminant
-- initialized in an allocator by the expression Disc_Exp is not deeper
-- than the level of the allocator type Alloc_Typ. An error message is
-- issued if this condition is violated. Specialized checks are done for
-- the cases of a constraint expression which is an access attribute or
-- an access discriminant.
procedure Check_Allocator_Discrim_Accessibility_Exprs
(Curr_Exp : Node_Id;
Alloc_Typ : Entity_Id);
-- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
-- across all expressions within a given conditional expression.
function In_Dispatching_Context return Boolean;
-- If the allocator is an actual in a call, it is allowed to be class-
-- wide when the context is not because it is a controlling actual.
-------------------------------------------
-- Check_Allocator_Discrim_Accessibility --
-------------------------------------------
procedure Check_Allocator_Discrim_Accessibility
(Disc_Exp : Node_Id;
Alloc_Typ : Entity_Id)
is
begin
if Type_Access_Level (Etype (Disc_Exp)) >
Deepest_Type_Access_Level (Alloc_Typ)
then
Error_Msg_N
("operand type has deeper level than allocator type", Disc_Exp);
-- When the expression is an Access attribute the level of the prefix
-- object must not be deeper than that of the allocator's type.
elsif Nkind (Disc_Exp) = N_Attribute_Reference
and then Get_Attribute_Id (Attribute_Name (Disc_Exp)) =
Attribute_Access
and then Static_Accessibility_Level
(Disc_Exp, Zero_On_Dynamic_Level)
> Deepest_Type_Access_Level (Alloc_Typ)
then
Error_Msg_N
("prefix of attribute has deeper level than allocator type",
Disc_Exp);
-- When the expression is an access discriminant the check is against
-- the level of the prefix object.
elsif Ekind (Etype (Disc_Exp)) = E_Anonymous_Access_Type
and then Nkind (Disc_Exp) = N_Selected_Component
and then Static_Accessibility_Level
(Disc_Exp, Zero_On_Dynamic_Level)
> Deepest_Type_Access_Level (Alloc_Typ)
then
Error_Msg_N
("access discriminant has deeper level than allocator type",
Disc_Exp);
-- All other cases are legal
else
null;
end if;
end Check_Allocator_Discrim_Accessibility;
-------------------------------------------------
-- Check_Allocator_Discrim_Accessibility_Exprs --
-------------------------------------------------
procedure Check_Allocator_Discrim_Accessibility_Exprs
(Curr_Exp : Node_Id;
Alloc_Typ : Entity_Id)
is
Alt : Node_Id;
Expr : Node_Id;
Disc_Exp : constant Node_Id := Original_Node (Curr_Exp);
begin
-- When conditional expressions are constant folded we know at
-- compile time which expression to check - so don't bother with
-- the rest of the cases.
if Nkind (Curr_Exp) = N_Attribute_Reference then
Check_Allocator_Discrim_Accessibility (Curr_Exp, Alloc_Typ);
-- Non-constant-folded if expressions
elsif Nkind (Disc_Exp) = N_If_Expression then
-- Check both expressions if they are still present in the face
-- of expansion.
Expr := Next (First (Expressions (Disc_Exp)));
if Present (Expr) then
Check_Allocator_Discrim_Accessibility_Exprs (Expr, Alloc_Typ);
Next (Expr);
if Present (Expr) then
Check_Allocator_Discrim_Accessibility_Exprs
(Expr, Alloc_Typ);
end if;
end if;
-- Non-constant-folded case expressions
elsif Nkind (Disc_Exp) = N_Case_Expression then
-- Check all alternatives
Alt := First (Alternatives (Disc_Exp));
while Present (Alt) loop
Check_Allocator_Discrim_Accessibility_Exprs
(Expression (Alt), Alloc_Typ);
Next (Alt);
end loop;
-- Base case, check the accessibility of the original node of the
-- expression.
else
Check_Allocator_Discrim_Accessibility (Disc_Exp, Alloc_Typ);
end if;
end Check_Allocator_Discrim_Accessibility_Exprs;
----------------------------
-- In_Dispatching_Context --
----------------------------
function In_Dispatching_Context return Boolean is
Par : constant Node_Id := Parent (N);
begin
return Nkind (Par) in N_Subprogram_Call
and then Is_Entity_Name (Name (Par))
and then Is_Dispatching_Operation (Entity (Name (Par)));
end In_Dispatching_Context;
-- Start of processing for Resolve_Allocator
begin
-- Replace general access with specific type
if Ekind (Etype (N)) = E_Allocator_Type then
Set_Etype (N, Base_Type (Typ));
end if;
if Is_Abstract_Type (Typ) then
Error_Msg_N ("type of allocator cannot be abstract", N);
end if;
-- For qualified expression, resolve the expression using the given
-- subtype (nothing to do for type mark, subtype indication)
if Nkind (E) = N_Qualified_Expression then
if Is_Class_Wide_Type (Etype (E))
and then not Is_Class_Wide_Type (Desig_T)
and then not In_Dispatching_Context
then
Error_Msg_N
("class-wide allocator not allowed for this access type", N);
end if;
-- Do a full resolution to apply constraint and predicate checks
Resolve_Qualified_Expression (E, Etype (E));
Check_Unset_Reference (Expression (E));
-- Allocators generated by the build-in-place expansion mechanism
-- are explicitly marked as coming from source but do not need to be
-- checked for limited initialization. To exclude this case, ensure
-- that the parent of the allocator is a source node.
-- The return statement constructed for an Expression_Function does
-- not come from source but requires a limited check.
if Is_Limited_Type (Etype (E))
and then Comes_From_Source (N)
and then
(Comes_From_Source (Parent (N))
or else
(Ekind (Current_Scope) = E_Function
and then Nkind (Original_Node (Unit_Declaration_Node
(Current_Scope))) = N_Expression_Function))
and then not In_Instance_Body
then
if not OK_For_Limited_Init (Etype (E), Expression (E)) then
if Nkind (Parent (N)) = N_Assignment_Statement then
Error_Msg_N
("illegal expression for initialized allocator of a "
& "limited type (RM 7.5 (2.7/2))", N);
else
Error_Msg_N
("initialization not allowed for limited types", N);
end if;
Explain_Limited_Type (Etype (E), N);
end if;
end if;
-- Calls to build-in-place functions are not currently supported in
-- allocators for access types associated with a simple storage pool.
-- Supporting such allocators may require passing additional implicit
-- parameters to build-in-place functions (or a significant revision
-- of the current b-i-p implementation to unify the handling for
-- multiple kinds of storage pools). ???
if Is_Limited_View (Desig_T)
and then Nkind (Expression (E)) = N_Function_Call
then
declare
Pool : constant Entity_Id :=
Associated_Storage_Pool (Root_Type (Typ));
begin
if Present (Pool)
and then
Present (Get_Rep_Pragma
(Etype (Pool), Name_Simple_Storage_Pool_Type))
then
Error_Msg_N
("limited function calls not yet supported in simple "
& "storage pool allocators", Expression (E));
end if;
end;
end if;
-- A special accessibility check is needed for allocators that
-- constrain access discriminants. The level of the type of the
-- expression used to constrain an access discriminant cannot be
-- deeper than the type of the allocator (in contrast to access
-- parameters, where the level of the actual can be arbitrary).
-- We can't use Valid_Conversion to perform this check because in
-- general the type of the allocator is unrelated to the type of
-- the access discriminant.
if Ekind (Typ) /= E_Anonymous_Access_Type
or else Is_Local_Anonymous_Access (Typ)
then
Subtyp := Entity (Subtype_Mark (E));
Aggr := Original_Node (Expression (E));
if Has_Discriminants (Subtyp)
and then Nkind (Aggr) in N_Aggregate | N_Extension_Aggregate
then
Discrim := First_Discriminant (Base_Type (Subtyp));
-- Get the first component expression of the aggregate
if Present (Expressions (Aggr)) then
Disc_Exp := First (Expressions (Aggr));
elsif Present (Component_Associations (Aggr)) then
Assoc := First (Component_Associations (Aggr));
if Present (Assoc) then
Disc_Exp := Expression (Assoc);
else
Disc_Exp := Empty;
end if;
else
Disc_Exp := Empty;
end if;
while Present (Discrim) and then Present (Disc_Exp) loop
if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
Check_Allocator_Discrim_Accessibility_Exprs
(Disc_Exp, Typ);
end if;
Next_Discriminant (Discrim);
if Present (Discrim) then
if Present (Assoc) then
Next (Assoc);
Disc_Exp := Expression (Assoc);
elsif Present (Next (Disc_Exp)) then
Next (Disc_Exp);
else
Assoc := First (Component_Associations (Aggr));
if Present (Assoc) then
Disc_Exp := Expression (Assoc);
else
Disc_Exp := Empty;
end if;
end if;
end if;
end loop;
end if;
end if;
-- For a subtype mark or subtype indication, freeze the subtype
else
Freeze_Expression (E);
if Is_Access_Constant (Typ) and then not No_Initialization (N) then
Error_Msg_N
("initialization required for access-to-constant allocator", N);
end if;
-- A special accessibility check is needed for allocators that
-- constrain access discriminants. The level of the type of the
-- expression used to constrain an access discriminant cannot be
-- deeper than the type of the allocator (in contrast to access
-- parameters, where the level of the actual can be arbitrary).
-- We can't use Valid_Conversion to perform this check because
-- in general the type of the allocator is unrelated to the type
-- of the access discriminant.
if Nkind (Original_Node (E)) = N_Subtype_Indication
and then (Ekind (Typ) /= E_Anonymous_Access_Type
or else Is_Local_Anonymous_Access (Typ))
then
Subtyp := Entity (Subtype_Mark (Original_Node (E)));
if Has_Discriminants (Subtyp) then
Discrim := First_Discriminant (Base_Type (Subtyp));
Constr := First (Constraints (Constraint (Original_Node (E))));
while Present (Discrim) and then Present (Constr) loop
if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
if Nkind (Constr) = N_Discriminant_Association then
Disc_Exp := Expression (Constr);
else
Disc_Exp := Constr;
end if;
Check_Allocator_Discrim_Accessibility_Exprs
(Disc_Exp, Typ);
end if;
Next_Discriminant (Discrim);
Next (Constr);
end loop;
end if;
end if;
end if;
-- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
-- check that the level of the type of the created object is not deeper
-- than the level of the allocator's access type, since extensions can
-- now occur at deeper levels than their ancestor types. This is a
-- static accessibility level check; a run-time check is also needed in
-- the case of an initialized allocator with a class-wide argument (see
-- Expand_Allocator_Expression).
if Ada_Version >= Ada_2005
and then Is_Class_Wide_Type (Desig_T)
then
declare
Exp_Typ : Entity_Id;
begin
if Nkind (E) = N_Qualified_Expression then
Exp_Typ := Etype (E);
elsif Nkind (E) = N_Subtype_Indication then
Exp_Typ := Entity (Subtype_Mark (Original_Node (E)));
else
Exp_Typ := Entity (E);
end if;
if Type_Access_Level (Exp_Typ) >
Deepest_Type_Access_Level (Typ)
then
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N
("type in allocator has deeper level than designated "
& "class-wide type<<", E);
Error_Msg_N ("\Program_Error [<<", E);
Rewrite (N,
Make_Raise_Program_Error (Sloc (N),
Reason => PE_Accessibility_Check_Failed));
Set_Etype (N, Typ);
-- Do not apply Ada 2005 accessibility checks on a class-wide
-- allocator if the type given in the allocator is a formal
-- type or within a formal package. A run-time check will be
-- performed in the instance.
elsif not Is_Generic_Type (Exp_Typ)
and then not In_Generic_Formal_Package (Exp_Typ)
then
Error_Msg_N
("type in allocator has deeper level than designated "
& "class-wide type", E);
end if;
end if;
end;
end if;
-- Check for allocation from an empty storage pool. But do not complain
-- if it's a return statement for a build-in-place function, because the
-- allocator is there just in case the caller uses an allocator. If the
-- caller does use an allocator, it will be caught at the call site.
if No_Pool_Assigned (Typ)
and then not Alloc_For_BIP_Return (N)
then
Error_Msg_N ("allocation from empty storage pool!", N);
-- If the context is an unchecked conversion, as may happen within an
-- inlined subprogram, the allocator is being resolved with its own
-- anonymous type. In that case, if the target type has a specific
-- storage pool, it must be inherited explicitly by the allocator type.
elsif Nkind (Parent (N)) = N_Unchecked_Type_Conversion
and then No (Associated_Storage_Pool (Typ))
then
Set_Associated_Storage_Pool
(Typ, Associated_Storage_Pool (Etype (Parent (N))));
end if;
if Ekind (Etype (N)) = E_Anonymous_Access_Type then
Check_Restriction (No_Anonymous_Allocators, N);
end if;
-- Check that an allocator with task parts isn't for a nested access
-- type when restriction No_Task_Hierarchy applies.
if not Is_Library_Level_Entity (Base_Type (Typ))
and then Has_Task (Base_Type (Desig_T))
then
Check_Restriction (No_Task_Hierarchy, N);
end if;
-- An illegal allocator may be rewritten as a raise Program_Error
-- statement.
if Nkind (N) = N_Allocator then
-- Avoid coextension processing for an allocator that is the
-- expansion of a build-in-place function call.
if Nkind (Original_Node (N)) = N_Allocator
and then Nkind (Expression (Original_Node (N))) =
N_Qualified_Expression
and then Nkind (Expression (Expression (Original_Node (N)))) =
N_Function_Call
and then Is_Expanded_Build_In_Place_Call
(Expression (Expression (Original_Node (N))))
then
null; -- b-i-p function call case
else
-- An anonymous access discriminant is the definition of a
-- coextension.
if Ekind (Typ) = E_Anonymous_Access_Type
and then Nkind (Associated_Node_For_Itype (Typ)) =
N_Discriminant_Specification
then
declare
Discr : constant Entity_Id :=
Defining_Identifier (Associated_Node_For_Itype (Typ));
begin
Check_Restriction (No_Coextensions, N);
-- Ada 2012 AI05-0052: If the designated type of the
-- allocator is limited, then the allocator shall not
-- be used to define the value of an access discriminant
-- unless the discriminated type is immutably limited.
if Ada_Version >= Ada_2012
and then Is_Limited_Type (Desig_T)
and then not Is_Limited_View (Scope (Discr))
then
Error_Msg_N
("only immutably limited types can have anonymous "
& "access discriminants designating a limited type",
N);
end if;
end;
-- Avoid marking an allocator as a dynamic coextension if it is
-- within a static construct.
if not Is_Static_Coextension (N) then
Set_Is_Dynamic_Coextension (N);
-- Finalization and deallocation of coextensions utilizes an
-- approximate implementation which does not directly adhere
-- to the semantic rules. Warn on potential issues involving
-- coextensions.
if Is_Controlled (Desig_T) then
Error_Msg_N
("??coextension will not be finalized when its "
& "associated owner is deallocated or finalized", N);
else
Error_Msg_N
("??coextension will not be deallocated when its "
& "associated owner is deallocated", N);
end if;
end if;
-- Cleanup for potential static coextensions
else
Set_Is_Dynamic_Coextension (N, False);
Set_Is_Static_Coextension (N, False);
-- Anonymous access-to-controlled objects are not finalized on
-- time because this involves run-time ownership and currently
-- this property is not available. In rare cases the object may
-- not be finalized at all. Warn on potential issues involving
-- anonymous access-to-controlled objects.
if Ekind (Typ) = E_Anonymous_Access_Type
and then Is_Controlled_Active (Desig_T)
then
Error_Msg_N
("??object designated by anonymous access object might "
& "not be finalized until its enclosing library unit "
& "goes out of scope", N);
Error_Msg_N ("\use named access type instead", N);
end if;
end if;
end if;
end if;
-- Report a simple error: if the designated object is a local task,
-- its body has not been seen yet, and its activation will fail an
-- elaboration check.
if Is_Task_Type (Desig_T)
and then Scope (Base_Type (Desig_T)) = Current_Scope
and then Is_Compilation_Unit (Current_Scope)
and then Ekind (Current_Scope) = E_Package
and then not In_Package_Body (Current_Scope)
then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("cannot activate task before body seen<<", N);
Error_Msg_N ("\Program_Error [<<", N);
end if;
-- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
-- type with a task component on a subpool. This action must raise
-- Program_Error at runtime.
if Ada_Version >= Ada_2012
and then Nkind (N) = N_Allocator
and then Present (Subpool_Handle_Name (N))
and then Has_Task (Desig_T)
then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("cannot allocate task on subpool<<", N);
Error_Msg_N ("\Program_Error [<<", N);
Rewrite (N,
Make_Raise_Program_Error (Sloc (N),
Reason => PE_Explicit_Raise));
Set_Etype (N, Typ);
end if;
end Resolve_Allocator;
---------------------------
-- Resolve_Arithmetic_Op --
---------------------------
-- Used for resolving all arithmetic operators except exponentiation
procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
TL : constant Entity_Id := Base_Type (Etype (L));
TR : constant Entity_Id := Base_Type (Etype (R));
T : Entity_Id;
Rop : Node_Id;
B_Typ : constant Entity_Id := Base_Type (Typ);
-- We do the resolution using the base type, because intermediate values
-- in expressions always are of the base type, not a subtype of it.
function Expected_Type_Is_Any_Real (N : Node_Id) return Boolean;
-- Returns True if N is in a context that expects "any real type"
function Is_Integer_Or_Universal (N : Node_Id) return Boolean;
-- Return True iff given type is Integer or universal real/integer
procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id);
-- Choose type of integer literal in fixed-point operation to conform
-- to available fixed-point type. T is the type of the other operand,
-- which is needed to determine the expected type of N.
procedure Set_Operand_Type (N : Node_Id);
-- Set operand type to T if universal
-------------------------------
-- Expected_Type_Is_Any_Real --
-------------------------------
function Expected_Type_Is_Any_Real (N : Node_Id) return Boolean is
begin
-- N is the expression after "delta" in a fixed_point_definition;
-- see RM-3.5.9(6):
return Nkind (Parent (N)) in N_Ordinary_Fixed_Point_Definition
| N_Decimal_Fixed_Point_Definition
-- N is one of the bounds in a real_range_specification;
-- see RM-3.5.7(5):
| N_Real_Range_Specification
-- N is the expression of a delta_constraint;
-- see RM-J.3(3):
| N_Delta_Constraint;
end Expected_Type_Is_Any_Real;
-----------------------------
-- Is_Integer_Or_Universal --
-----------------------------
function Is_Integer_Or_Universal (N : Node_Id) return Boolean is
T : Entity_Id;
Index : Interp_Index;
It : Interp;
begin
if not Is_Overloaded (N) then
T := Etype (N);
return Base_Type (T) = Base_Type (Standard_Integer)
or else T = Universal_Integer
or else T = Universal_Real;
else
Get_First_Interp (N, Index, It);
while Present (It.Typ) loop
if Base_Type (It.Typ) = Base_Type (Standard_Integer)
or else It.Typ = Universal_Integer
or else It.Typ = Universal_Real
then
return True;
end if;
Get_Next_Interp (Index, It);
end loop;
end if;
return False;
end Is_Integer_Or_Universal;
----------------------------
-- Set_Mixed_Mode_Operand --
----------------------------
procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id) is
Index : Interp_Index;
It : Interp;
begin
if Universal_Interpretation (N) = Universal_Integer then
-- A universal integer literal is resolved as standard integer
-- except in the case of a fixed-point result, where we leave it
-- as universal (to be handled by Exp_Fixd later on)
if Is_Fixed_Point_Type (T) then
Resolve (N, Universal_Integer);
else
Resolve (N, Standard_Integer);
end if;
elsif Universal_Interpretation (N) = Universal_Real
and then (T = Base_Type (Standard_Integer)
or else T = Universal_Integer
or else T = Universal_Real)
then
-- A universal real can appear in a fixed-type context. We resolve
-- the literal with that context, even though this might raise an
-- exception prematurely (the other operand may be zero).
Resolve (N, B_Typ);
elsif Etype (N) = Base_Type (Standard_Integer)
and then T = Universal_Real
and then Is_Overloaded (N)
then
-- Integer arg in mixed-mode operation. Resolve with universal
-- type, in case preference rule must be applied.
Resolve (N, Universal_Integer);
elsif Etype (N) = T and then B_Typ /= Universal_Fixed then
-- If the operand is part of a fixed multiplication operation,
-- a conversion will be applied to each operand, so resolve it
-- with its own type.
if Nkind (Parent (N)) in N_Op_Divide | N_Op_Multiply then
Resolve (N);
else
-- Not a mixed-mode operation, resolve with context
Resolve (N, B_Typ);
end if;
elsif Etype (N) = Any_Fixed then
-- N may itself be a mixed-mode operation, so use context type
Resolve (N, B_Typ);
elsif Is_Fixed_Point_Type (T)
and then B_Typ = Universal_Fixed
and then Is_Overloaded (N)
then
-- Must be (fixed * fixed) operation, operand must have one
-- compatible interpretation.
Resolve (N, Any_Fixed);
elsif Is_Fixed_Point_Type (B_Typ)
and then (T = Universal_Real or else Is_Fixed_Point_Type (T))
and then Is_Overloaded (N)
then
-- C * F(X) in a fixed context, where C is a real literal or a
-- fixed-point expression. F must have either a fixed type
-- interpretation or an integer interpretation, but not both.
Get_First_Interp (N, Index, It);
while Present (It.Typ) loop
if Base_Type (It.Typ) = Base_Type (Standard_Integer) then
if Analyzed (N) then
Error_Msg_N ("ambiguous operand in fixed operation", N);
else
Resolve (N, Standard_Integer);
end if;
elsif Is_Fixed_Point_Type (It.Typ) then
if Analyzed (N) then
Error_Msg_N ("ambiguous operand in fixed operation", N);
else
Resolve (N, It.Typ);
end if;
end if;
Get_Next_Interp (Index, It);
end loop;
-- Reanalyze the literal with the fixed type of the context. If
-- context is Universal_Fixed, we are within a conversion, leave
-- the literal as a universal real because there is no usable
-- fixed type, and the target of the conversion plays no role in
-- the resolution.
declare
Op2 : Node_Id;
T2 : Entity_Id;
begin
if N = L then
Op2 := R;
else
Op2 := L;
end if;
if B_Typ = Universal_Fixed
and then Nkind (Op2) = N_Real_Literal
then
T2 := Universal_Real;
else
T2 := B_Typ;
end if;
Set_Analyzed (Op2, False);
Resolve (Op2, T2);
end;
-- A universal real conditional expression can appear in a fixed-type
-- context and must be resolved with that context to facilitate the
-- code generation in the back end. However, If the context is
-- Universal_fixed (i.e. as an operand of a multiplication/division
-- involving a fixed-point operand) the conditional expression must
-- resolve to a unique visible fixed_point type, normally Duration.
elsif Nkind (N) in N_Case_Expression | N_If_Expression
and then Etype (N) = Universal_Real
and then Is_Fixed_Point_Type (B_Typ)
then
if B_Typ = Universal_Fixed then
Resolve (N, Unique_Fixed_Point_Type (N));
else
Resolve (N, B_Typ);
end if;
else
Resolve (N);
end if;
end Set_Mixed_Mode_Operand;
----------------------
-- Set_Operand_Type --
----------------------
procedure Set_Operand_Type (N : Node_Id) is
begin
if Etype (N) = Universal_Integer
or else Etype (N) = Universal_Real
then
Set_Etype (N, T);
end if;
end Set_Operand_Type;
-- Start of processing for Resolve_Arithmetic_Op
begin
if Comes_From_Source (N)
and then Ekind (Entity (N)) = E_Function
and then Is_Imported (Entity (N))
and then Is_Intrinsic_Subprogram (Entity (N))
then
Resolve_Intrinsic_Operator (N, Typ);
return;
-- Special-case for mixed-mode universal expressions or fixed point type
-- operation: each argument is resolved separately. The same treatment
-- is required if one of the operands of a fixed point operation is
-- universal real, since in this case we don't do a conversion to a
-- specific fixed-point type (instead the expander handles the case).
-- Set the type of the node to its universal interpretation because
-- legality checks on an exponentiation operand need the context.
elsif (B_Typ = Universal_Integer or else B_Typ = Universal_Real)
and then Present (Universal_Interpretation (L))
and then Present (Universal_Interpretation (R))
then
Set_Etype (N, B_Typ);
Resolve (L, Universal_Interpretation (L));
Resolve (R, Universal_Interpretation (R));
elsif (B_Typ = Universal_Real
or else Etype (N) = Universal_Fixed
or else (Etype (N) = Any_Fixed
and then Is_Fixed_Point_Type (B_Typ))
or else (Is_Fixed_Point_Type (B_Typ)
and then (Is_Integer_Or_Universal (L)
or else
Is_Integer_Or_Universal (R))))
and then Nkind (N) in N_Op_Multiply | N_Op_Divide
then
if TL = Universal_Integer or else TR = Universal_Integer then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- If context is a fixed type and one operand is integer, the other
-- is resolved with the type of the context.
if Is_Fixed_Point_Type (B_Typ)
and then (Base_Type (TL) = Base_Type (Standard_Integer)
or else TL = Universal_Integer)
then
Resolve (R, B_Typ);
Resolve (L, TL);
elsif Is_Fixed_Point_Type (B_Typ)
and then (Base_Type (TR) = Base_Type (Standard_Integer)
or else TR = Universal_Integer)
then
Resolve (L, B_Typ);
Resolve (R, TR);
-- If both operands are universal and the context is a floating
-- point type, the operands are resolved to the type of the context.
elsif Is_Floating_Point_Type (B_Typ) then
Resolve (L, B_Typ);
Resolve (R, B_Typ);
else
Set_Mixed_Mode_Operand (L, TR);
Set_Mixed_Mode_Operand (R, TL);
end if;
-- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
-- multiplying operators from being used when the expected type is
-- also universal_fixed. Note that B_Typ will be Universal_Fixed in
-- some cases where the expected type is actually Any_Real;
-- Expected_Type_Is_Any_Real takes care of that case.
if Etype (N) = Universal_Fixed
or else Etype (N) = Any_Fixed
then
if B_Typ = Universal_Fixed
and then not Expected_Type_Is_Any_Real (N)
and then Nkind (Parent (N)) not in
N_Type_Conversion | N_Unchecked_Type_Conversion
then
Error_Msg_N ("type cannot be determined from context!", N);
Error_Msg_N ("\explicit conversion to result type required", N);
Set_Etype (L, Any_Type);
Set_Etype (R, Any_Type);
else
if Ada_Version = Ada_83
and then Etype (N) = Universal_Fixed
and then Nkind (Parent (N)) not in
N_Type_Conversion | N_Unchecked_Type_Conversion
then
Error_Msg_N
("(Ada 83) fixed-point operation needs explicit "
& "conversion", N);
end if;
-- The expected type is "any real type" in contexts like
-- type T is delta <universal_fixed-expression> ...
-- in which case we need to set the type to Universal_Real
-- so that static expression evaluation will work properly.
if Expected_Type_Is_Any_Real (N) then
Set_Etype (N, Universal_Real);
else
Set_Etype (N, B_Typ);
end if;
end if;
elsif Is_Fixed_Point_Type (B_Typ)
and then (Is_Integer_Or_Universal (L)
or else Nkind (L) = N_Real_Literal
or else Nkind (R) = N_Real_Literal
or else Is_Integer_Or_Universal (R))
then
Set_Etype (N, B_Typ);
elsif Etype (N) = Any_Fixed then
-- If no previous errors, this is only possible if one operand is
-- overloaded and the context is universal. Resolve as such.
Set_Etype (N, B_Typ);
end if;
else
if (TL = Universal_Integer or else TL = Universal_Real)
and then
(TR = Universal_Integer or else TR = Universal_Real)
then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- If the context is Universal_Fixed and the operands are also
-- universal fixed, this is an error, unless there is only one
-- applicable fixed_point type (usually Duration).
if B_Typ = Universal_Fixed and then Etype (L) = Universal_Fixed then
T := Unique_Fixed_Point_Type (N);
if T = Any_Type then
Set_Etype (N, T);
return;
else
Resolve (L, T);
Resolve (R, T);
end if;
else
Resolve (L, B_Typ);
Resolve (R, B_Typ);
end if;
-- If one of the arguments was resolved to a non-universal type.
-- label the result of the operation itself with the same type.
-- Do the same for the universal argument, if any.
T := Intersect_Types (L, R);
Set_Etype (N, Base_Type (T));
Set_Operand_Type (L);
Set_Operand_Type (R);
end if;
Generate_Operator_Reference (N, Typ);
Analyze_Dimension (N);
Eval_Arithmetic_Op (N);
-- Set overflow and division checking bit
if Nkind (N) in N_Op then
if not Overflow_Checks_Suppressed (Etype (N)) then
Enable_Overflow_Check (N);
end if;
-- Give warning if explicit division by zero
if Nkind (N) in N_Op_Divide | N_Op_Rem | N_Op_Mod
and then not Division_Checks_Suppressed (Etype (N))
then
Rop := Right_Opnd (N);
if Compile_Time_Known_Value (Rop)
and then ((Is_Integer_Type (Etype (Rop))
and then Expr_Value (Rop) = Uint_0)
or else
(Is_Real_Type (Etype (Rop))
and then Expr_Value_R (Rop) = Ureal_0))
then
-- Specialize the warning message according to the operation.
-- When SPARK_Mode is On, force a warning instead of an error
-- in that case, as this likely corresponds to deactivated
-- code. The following warnings are for the case
case Nkind (N) is
when N_Op_Divide =>
-- For division, we have two cases, for float division
-- of an unconstrained float type, on a machine where
-- Machine_Overflows is false, we don't get an exception
-- at run-time, but rather an infinity or Nan. The Nan
-- case is pretty obscure, so just warn about infinities.
if Is_Floating_Point_Type (Typ)
and then not Is_Constrained (Typ)
and then not Machine_Overflows_On_Target
then
Error_Msg_N
("float division by zero, may generate "
& "'+'/'- infinity??", Right_Opnd (N));
-- For all other cases, we get a Constraint_Error
else
Apply_Compile_Time_Constraint_Error
(N, "division by zero??", CE_Divide_By_Zero,
Loc => Sloc (Right_Opnd (N)),
Warn => SPARK_Mode = On);
end if;
when N_Op_Rem =>
Apply_Compile_Time_Constraint_Error
(N, "rem with zero divisor??", CE_Divide_By_Zero,
Loc => Sloc (Right_Opnd (N)),
Warn => SPARK_Mode = On);
when N_Op_Mod =>
Apply_Compile_Time_Constraint_Error
(N, "mod with zero divisor??", CE_Divide_By_Zero,
Loc => Sloc (Right_Opnd (N)),
Warn => SPARK_Mode = On);
-- Division by zero can only happen with division, rem,
-- and mod operations.
when others =>
raise Program_Error;
end case;
-- In GNATprove mode, we enable the division check so that
-- GNATprove will issue a message if it cannot be proved.
if GNATprove_Mode then
Activate_Division_Check (N);
end if;
-- Otherwise just set the flag to check at run time
else
Activate_Division_Check (N);
end if;
end if;
-- If Restriction No_Implicit_Conditionals is active, then it is
-- violated if either operand can be negative for mod, or for rem
-- if both operands can be negative.
if Restriction_Check_Required (No_Implicit_Conditionals)
and then Nkind (N) in N_Op_Rem | N_Op_Mod
then
declare
Lo : Uint;
Hi : Uint;
OK : Boolean;
LNeg : Boolean;
RNeg : Boolean;
-- Set if corresponding operand might be negative
begin
Determine_Range
(Left_Opnd (N), OK, Lo, Hi, Assume_Valid => True);
LNeg := (not OK) or else Lo < 0;
Determine_Range
(Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True);
RNeg := (not OK) or else Lo < 0;
-- Check if we will be generating conditionals. There are two
-- cases where that can happen, first for REM, the only case
-- is largest negative integer mod -1, where the division can
-- overflow, but we still have to give the right result. The
-- front end generates a test for this annoying case. Here we
-- just test if both operands can be negative (that's what the
-- expander does, so we match its logic here).
-- The second case is mod where either operand can be negative.
-- In this case, the back end has to generate additional tests.
if (Nkind (N) = N_Op_Rem and then (LNeg and RNeg))
or else
(Nkind (N) = N_Op_Mod and then (LNeg or RNeg))
then
Check_Restriction (No_Implicit_Conditionals, N);
end if;
end;
end if;
end if;
Check_Unset_Reference (L);
Check_Unset_Reference (R);
end Resolve_Arithmetic_Op;
------------------
-- Resolve_Call --
------------------
procedure Resolve_Call (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
Subp : constant Node_Id := Name (N);
Body_Id : Entity_Id;
I : Interp_Index;
It : Interp;
Nam : Entity_Id;
Nam_Decl : Node_Id;
Nam_UA : Entity_Id;
Norm_OK : Boolean;
Rtype : Entity_Id;
Scop : Entity_Id;
begin
-- Preserve relevant elaboration-related attributes of the context which
-- are no longer available or very expensive to recompute once analysis,
-- resolution, and expansion are over.
Mark_Elaboration_Attributes
(N_Id => N,
Checks => True,
Modes => True,
Warnings => True);
-- The context imposes a unique interpretation with type Typ on a
-- procedure or function call. Find the entity of the subprogram that
-- yields the expected type, and propagate the corresponding formal
-- constraints on the actuals. The caller has established that an
-- interpretation exists, and emitted an error if not unique.
-- First deal with the case of a call to an access-to-subprogram,
-- dereference made explicit in Analyze_Call.
if Ekind (Etype (Subp)) = E_Subprogram_Type then
if not Is_Overloaded (Subp) then
Nam := Etype (Subp);
else
-- Find the interpretation whose type (a subprogram type) has a
-- return type that is compatible with the context. Analysis of
-- the node has established that one exists.
Nam := Empty;
Get_First_Interp (Subp, I, It);
while Present (It.Typ) loop
if Covers (Typ, Etype (It.Typ)) then
Nam := It.Typ;
exit;
end if;
Get_Next_Interp (I, It);
end loop;
if No (Nam) then
raise Program_Error;
end if;
end if;
-- If the prefix is not an entity, then resolve it
if not Is_Entity_Name (Subp) then
Resolve (Subp, Nam);
end if;
-- For an indirect call, we always invalidate checks, since we do not
-- know whether the subprogram is local or global. Yes we could do
-- better here, e.g. by knowing that there are no local subprograms,
-- but it does not seem worth the effort. Similarly, we kill all
-- knowledge of current constant values.
Kill_Current_Values;
-- If this is a procedure call which is really an entry call, do
-- the conversion of the procedure call to an entry call. Protected
-- operations use the same circuitry because the name in the call
-- can be an arbitrary expression with special resolution rules.
elsif Nkind (Subp) in N_Selected_Component | N_Indexed_Component
or else (Is_Entity_Name (Subp) and then Is_Entry (Entity (Subp)))
then
Resolve_Entry_Call (N, Typ);
if Legacy_Elaboration_Checks then
Check_Elab_Call (N);
end if;
-- Annotate the tree by creating a call marker in case the original
-- call is transformed by expansion. The call marker is automatically
-- saved for later examination by the ABE Processing phase.
Build_Call_Marker (N);
-- Kill checks and constant values, as above for indirect case
-- Who knows what happens when another task is activated?
Kill_Current_Values;
return;
-- Normal subprogram call with name established in Resolve
elsif not Is_Type (Entity (Subp)) then
Nam := Entity (Subp);
Set_Entity_With_Checks (Subp, Nam);
-- Otherwise we must have the case of an overloaded call
else
pragma Assert (Is_Overloaded (Subp));
-- Initialize Nam to prevent warning (we know it will be assigned
-- in the loop below, but the compiler does not know that).
Nam := Empty;
Get_First_Interp (Subp, I, It);
while Present (It.Typ) loop
if Covers (Typ, It.Typ) then
Nam := It.Nam;
Set_Entity_With_Checks (Subp, Nam);
exit;
end if;
Get_Next_Interp (I, It);
end loop;
end if;
-- Check that a call to Current_Task does not occur in an entry body
if Is_RTE (Nam, RE_Current_Task) then
declare
P : Node_Id;
begin
P := N;
loop
P := Parent (P);
-- Exclude calls that occur within the default of a formal
-- parameter of the entry, since those are evaluated outside
-- of the body.
exit when No (P) or else Nkind (P) = N_Parameter_Specification;
if Nkind (P) = N_Entry_Body
or else (Nkind (P) = N_Subprogram_Body
and then Is_Entry_Barrier_Function (P))
then
Rtype := Etype (N);
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_NE
("& should not be used in entry body (RM C.7(17))<<",
N, Nam);
Error_Msg_NE ("\Program_Error [<<", N, Nam);
Rewrite (N,
Make_Raise_Program_Error (Loc,
Reason => PE_Current_Task_In_Entry_Body));
Set_Etype (N, Rtype);
return;
end if;
end loop;
end;
end if;
-- Check that a procedure call does not occur in the context of the
-- entry call statement of a conditional or timed entry call. Note that
-- the case of a call to a subprogram renaming of an entry will also be
-- rejected. The test for N not being an N_Entry_Call_Statement is
-- defensive, covering the possibility that the processing of entry
-- calls might reach this point due to later modifications of the code
-- above.
if Nkind (Parent (N)) = N_Entry_Call_Alternative
and then Nkind (N) /= N_Entry_Call_Statement
and then Entry_Call_Statement (Parent (N)) = N
then
if Ada_Version < Ada_2005 then
Error_Msg_N ("entry call required in select statement", N);
-- Ada 2005 (AI-345): If a procedure_call_statement is used
-- for a procedure_or_entry_call, the procedure_name or
-- procedure_prefix of the procedure_call_statement shall denote
-- an entry renamed by a procedure, or (a view of) a primitive
-- subprogram of a limited interface whose first parameter is
-- a controlling parameter.
elsif Nkind (N) = N_Procedure_Call_Statement
and then not Is_Renamed_Entry (Nam)
and then not Is_Controlling_Limited_Procedure (Nam)
then
Error_Msg_N
("entry call or dispatching primitive of interface required", N);
end if;
end if;
-- Check that this is not a call to a protected procedure or entry from
-- within a protected function.
Check_Internal_Protected_Use (N, Nam);
-- Freeze the subprogram name if not in a spec-expression. Note that
-- we freeze procedure calls as well as function calls. Procedure calls
-- are not frozen according to the rules (RM 13.14(14)) because it is
-- impossible to have a procedure call to a non-frozen procedure in
-- pure Ada, but in the code that we generate in the expander, this
-- rule needs extending because we can generate procedure calls that
-- need freezing.
-- In Ada 2012, expression functions may be called within pre/post
-- conditions of subsequent functions or expression functions. Such
-- calls do not freeze when they appear within generated bodies,
-- (including the body of another expression function) which would
-- place the freeze node in the wrong scope. An expression function
-- is frozen in the usual fashion, by the appearance of a real body,
-- or at the end of a declarative part. However an implicit call to
-- an expression function may appear when it is part of a default
-- expression in a call to an initialization procedure, and must be
-- frozen now, even if the body is inserted at a later point.
-- Otherwise, the call freezes the expression if expander is active,
-- for example as part of an object declaration.
if Is_Entity_Name (Subp)
and then not In_Spec_Expression
and then not Is_Expression_Function_Or_Completion (Current_Scope)
and then
(not Is_Expression_Function_Or_Completion (Entity (Subp))
or else Expander_Active)
then
if Is_Expression_Function (Entity (Subp)) then
-- Force freeze of expression function in call
Set_Comes_From_Source (Subp, True);
Set_Must_Not_Freeze (Subp, False);
end if;
Freeze_Expression (Subp);
end if;
-- For a predefined operator, the type of the result is the type imposed
-- by context, except for a predefined operation on universal fixed.
-- Otherwise the type of the call is the type returned by the subprogram
-- being called.
if Is_Predefined_Op (Nam) then
if Etype (N) /= Universal_Fixed then
Set_Etype (N, Typ);
end if;
-- If the subprogram returns an array type, and the context requires the
-- component type of that array type, the node is really an indexing of
-- the parameterless call. Resolve as such. A pathological case occurs
-- when the type of the component is an access to the array type. In
-- this case the call is truly ambiguous. If the call is to an intrinsic
-- subprogram, it can't be an indexed component. This check is necessary
-- because if it's Unchecked_Conversion, and we have "type T_Ptr is
-- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
-- pointers to the same array), the compiler gets confused and does an
-- infinite recursion.
elsif (Needs_No_Actuals (Nam) or else Needs_One_Actual (Nam))
and then
((Is_Array_Type (Etype (Nam))
and then Covers (Typ, Component_Type (Etype (Nam))))
or else
(Is_Access_Type (Etype (Nam))
and then Is_Array_Type (Designated_Type (Etype (Nam)))
and then
Covers (Typ, Component_Type (Designated_Type (Etype (Nam))))
and then not Is_Intrinsic_Subprogram (Entity (Subp))))
then
declare
Index_Node : Node_Id;
New_Subp : Node_Id;
Ret_Type : constant Entity_Id := Etype (Nam);
begin
-- If this is a parameterless call there is no ambiguity and the
-- call has the type of the function.
if No (First_Actual (N)) then
Set_Etype (N, Etype (Nam));
if Present (First_Formal (Nam)) then
Resolve_Actuals (N, Nam);
end if;
-- Annotate the tree by creating a call marker in case the
-- original call is transformed by expansion. The call marker
-- is automatically saved for later examination by the ABE
-- Processing phase.
Build_Call_Marker (N);
elsif Is_Access_Type (Ret_Type)
and then Ret_Type = Component_Type (Designated_Type (Ret_Type))
then
Error_Msg_N
("cannot disambiguate function call and indexing", N);
else
New_Subp := Relocate_Node (Subp);
-- The called entity may be an explicit dereference, in which
-- case there is no entity to set.
if Nkind (New_Subp) /= N_Explicit_Dereference then
Set_Entity (Subp, Nam);
end if;
if (Is_Array_Type (Ret_Type)
and then Component_Type (Ret_Type) /= Any_Type)
or else
(Is_Access_Type (Ret_Type)
and then
Component_Type (Designated_Type (Ret_Type)) /= Any_Type)
then
if Needs_No_Actuals (Nam) then
-- Indexed call to a parameterless function
Index_Node :=
Make_Indexed_Component (Loc,
Prefix =>
Make_Function_Call (Loc, Name => New_Subp),
Expressions => Parameter_Associations (N));
else
-- An Ada 2005 prefixed call to a primitive operation
-- whose first parameter is the prefix. This prefix was
-- prepended to the parameter list, which is actually a
-- list of indexes. Remove the prefix in order to build
-- the proper indexed component.
Index_Node :=
Make_Indexed_Component (Loc,
Prefix =>
Make_Function_Call (Loc,
Name => New_Subp,
Parameter_Associations =>
New_List
(Remove_Head (Parameter_Associations (N)))),
Expressions => Parameter_Associations (N));
end if;
-- Preserve the parenthesis count of the node
Set_Paren_Count (Index_Node, Paren_Count (N));
-- Since we are correcting a node classification error made
-- by the parser, we call Replace rather than Rewrite.
Replace (N, Index_Node);
Set_Etype (Prefix (N), Ret_Type);
Set_Etype (N, Typ);
if Legacy_Elaboration_Checks then
Check_Elab_Call (Prefix (N));
end if;
-- Annotate the tree by creating a call marker in case
-- the original call is transformed by expansion. The call
-- marker is automatically saved for later examination by
-- the ABE Processing phase.
Build_Call_Marker (Prefix (N));
Resolve_Indexed_Component (N, Typ);
end if;
end if;
return;
end;
else
-- If the called function is not declared in the main unit and it
-- returns the limited view of type then use the available view (as
-- is done in Try_Object_Operation) to prevent back-end confusion;
-- for the function entity itself. The call must appear in a context
-- where the nonlimited view is available. If the function entity is
-- in the extended main unit then no action is needed, because the
-- back end handles this case. In either case the type of the call
-- is the nonlimited view.
if From_Limited_With (Etype (Nam))
and then Present (Available_View (Etype (Nam)))
then
Set_Etype (N, Available_View (Etype (Nam)));
if not In_Extended_Main_Code_Unit (Nam) then
Set_Etype (Nam, Available_View (Etype (Nam)));
end if;
else
Set_Etype (N, Etype (Nam));
end if;
end if;
-- In the case where the call is to an overloaded subprogram, Analyze
-- calls Normalize_Actuals once per overloaded subprogram. Therefore in
-- such a case Normalize_Actuals needs to be called once more to order
-- the actuals correctly. Otherwise the call will have the ordering
-- given by the last overloaded subprogram whether this is the correct
-- one being called or not.
if Is_Overloaded (Subp) then
Normalize_Actuals (N, Nam, False, Norm_OK);
pragma Assert (Norm_OK);
end if;
-- In any case, call is fully resolved now. Reset Overload flag, to
-- prevent subsequent overload resolution if node is analyzed again
Set_Is_Overloaded (Subp, False);
Set_Is_Overloaded (N, False);
-- A Ghost entity must appear in a specific context
if Is_Ghost_Entity (Nam) and then Comes_From_Source (N) then
Check_Ghost_Context (Nam, N);
end if;
-- If we are calling the current subprogram from immediately within its
-- body, then that is the case where we can sometimes detect cases of
-- infinite recursion statically. Do not try this in case restriction
-- No_Recursion is in effect anyway, and do it only for source calls.
if Comes_From_Source (N) then
Scop := Current_Scope;
-- Issue warning for possible infinite recursion in the absence
-- of the No_Recursion restriction.
if Same_Or_Aliased_Subprograms (Nam, Scop)
and then not Restriction_Active (No_Recursion)
and then not Is_Static_Function (Scop)
and then Check_Infinite_Recursion (N)
then
-- Here we detected and flagged an infinite recursion, so we do
-- not need to test the case below for further warnings. Also we
-- are all done if we now have a raise SE node.
if Nkind (N) = N_Raise_Storage_Error then
return;
end if;
-- If call is to immediately containing subprogram, then check for
-- the case of a possible run-time detectable infinite recursion.
else
Scope_Loop : while Scop /= Standard_Standard loop
if Same_Or_Aliased_Subprograms (Nam, Scop) then
-- Ada 202x (AI12-0075): Static functions are never allowed
-- to make a recursive call, as specified by 6.8(5.4/5).
if Is_Static_Function (Scop) then
Error_Msg_N
("recursive call not allowed in static expression "
& "function", N);
Set_Error_Posted (Scop);
exit Scope_Loop;
end if;
-- Although in general case, recursion is not statically
-- checkable, the case of calling an immediately containing
-- subprogram is easy to catch.
if not Is_Ignored_Ghost_Entity (Nam) then
Check_Restriction (No_Recursion, N);
end if;
-- If the recursive call is to a parameterless subprogram,
-- then even if we can't statically detect infinite
-- recursion, this is pretty suspicious, and we output a
-- warning. Furthermore, we will try later to detect some
-- cases here at run time by expanding checking code (see
-- Detect_Infinite_Recursion in package Exp_Ch6).
-- If the recursive call is within a handler, do not emit a
-- warning, because this is a common idiom: loop until input
-- is correct, catch illegal input in handler and restart.
if No (First_Formal (Nam))
and then Etype (Nam) = Standard_Void_Type
and then not Error_Posted (N)
and then Nkind (Parent (N)) /= N_Exception_Handler
then
-- For the case of a procedure call. We give the message
-- only if the call is the first statement in a sequence
-- of statements, or if all previous statements are
-- simple assignments. This is simply a heuristic to
-- decrease false positives, without losing too many good
-- warnings. The idea is that these previous statements
-- may affect global variables the procedure depends on.
-- We also exclude raise statements, that may arise from
-- constraint checks and are probably unrelated to the
-- intended control flow.
if Nkind (N) = N_Procedure_Call_Statement
and then Is_List_Member (N)
then
declare
P : Node_Id;
begin
P := Prev (N);
while Present (P) loop
if Nkind (P) not in N_Assignment_Statement
| N_Raise_Constraint_Error
then
exit Scope_Loop;
end if;
Prev (P);
end loop;
end;
end if;
-- Do not give warning if we are in a conditional context
declare
K : constant Node_Kind := Nkind (Parent (N));
begin
if (K = N_Loop_Statement
and then Present (Iteration_Scheme (Parent (N))))
or else K = N_If_Statement
or else K = N_Elsif_Part
or else K = N_Case_Statement_Alternative
then
exit Scope_Loop;
end if;
end;
-- Here warning is to be issued
Set_Has_Recursive_Call (Nam);
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("possible infinite recursion<<!", N);
Error_Msg_N ("\Storage_Error ]<<!", N);
end if;
exit Scope_Loop;
end if;
Scop := Scope (Scop);
end loop Scope_Loop;
end if;
end if;
-- Check obsolescent reference to Ada.Characters.Handling subprogram
Check_Obsolescent_2005_Entity (Nam, Subp);
-- If subprogram name is a predefined operator, it was given in
-- functional notation. Replace call node with operator node, so
-- that actuals can be resolved appropriately.
if Is_Predefined_Op (Nam) or else Ekind (Nam) = E_Operator then
Make_Call_Into_Operator (N, Typ, Entity (Name (N)));
return;
elsif Present (Alias (Nam))
and then Is_Predefined_Op (Alias (Nam))
then
Resolve_Actuals (N, Nam);
Make_Call_Into_Operator (N, Typ, Alias (Nam));
return;
end if;
-- Create a transient scope if the resulting type requires it
-- There are several notable exceptions:
-- a) In init procs, the transient scope overhead is not needed, and is
-- even incorrect when the call is a nested initialization call for a
-- component whose expansion may generate adjust calls. However, if the
-- call is some other procedure call within an initialization procedure
-- (for example a call to Create_Task in the init_proc of the task
-- run-time record) a transient scope must be created around this call.
-- b) Enumeration literal pseudo-calls need no transient scope
-- c) Intrinsic subprograms (Unchecked_Conversion and source info
-- functions) do not use the secondary stack even though the return
-- type may be unconstrained.
-- d) Calls to a build-in-place function, since such functions may
-- allocate their result directly in a target object, and cases where
-- the result does get allocated in the secondary stack are checked for
-- within the specialized Exp_Ch6 procedures for expanding those
-- build-in-place calls.
-- e) Calls to inlinable expression functions do not use the secondary
-- stack (since the call will be replaced by its returned object).
-- f) If the subprogram is marked Inline_Always, then even if it returns
-- an unconstrained type the call does not require use of the secondary
-- stack. However, inlining will only take place if the body to inline
-- is already present. It may not be available if e.g. the subprogram is
-- declared in a child instance.
-- g) If the subprogram is a static expression function and the call is
-- a static call (the actuals are all static expressions), then we never
-- want to create a transient scope (this could occur in the case of a
-- static string-returning call).
if Is_Inlined (Nam)
and then Has_Pragma_Inline (Nam)
and then Nkind (Unit_Declaration_Node (Nam)) = N_Subprogram_Declaration
and then Present (Body_To_Inline (Unit_Declaration_Node (Nam)))
then
null;
elsif Ekind (Nam) = E_Enumeration_Literal
or else Is_Build_In_Place_Function (Nam)
or else Is_Intrinsic_Subprogram (Nam)
or else Is_Inlinable_Expression_Function (Nam)
or else Is_Static_Function_Call (N)
then
null;
-- A return statement from an ignored Ghost function does not use the
-- secondary stack (or any other one).
elsif Expander_Active
and then Ekind (Nam) in E_Function | E_Subprogram_Type
and then Requires_Transient_Scope (Etype (Nam))
and then not Is_Ignored_Ghost_Entity (Nam)
then
Establish_Transient_Scope (N, Manage_Sec_Stack => True);
-- If the call appears within the bounds of a loop, it will be
-- rewritten and reanalyzed, nothing left to do here.
if Nkind (N) /= N_Function_Call then
return;
end if;
end if;
-- A protected function cannot be called within the definition of the
-- enclosing protected type, unless it is part of a pre/postcondition
-- on another protected operation. This may appear in the entry wrapper
-- created for an entry with preconditions.
if Is_Protected_Type (Scope (Nam))
and then In_Open_Scopes (Scope (Nam))
and then not Has_Completion (Scope (Nam))
and then not In_Spec_Expression
and then not Is_Entry_Wrapper (Current_Scope)
then
Error_Msg_NE
("& cannot be called before end of protected definition", N, Nam);
end if;
-- Propagate interpretation to actuals, and add default expressions
-- where needed.
if Present (First_Formal (Nam)) then
Resolve_Actuals (N, Nam);
-- Overloaded literals are rewritten as function calls, for purpose of
-- resolution. After resolution, we can replace the call with the
-- literal itself.
elsif Ekind (Nam) = E_Enumeration_Literal then
Copy_Node (Subp, N);
Resolve_Entity_Name (N, Typ);
-- Avoid validation, since it is a static function call
Generate_Reference (Nam, Subp);
return;
end if;
-- If the subprogram is not global, then kill all saved values and
-- checks. This is a bit conservative, since in many cases we could do
-- better, but it is not worth the effort. Similarly, we kill constant
-- values. However we do not need to do this for internal entities
-- (unless they are inherited user-defined subprograms), since they
-- are not in the business of molesting local values.
-- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
-- kill all checks and values for calls to global subprograms. This
-- takes care of the case where an access to a local subprogram is
-- taken, and could be passed directly or indirectly and then called
-- from almost any context.
-- Note: we do not do this step till after resolving the actuals. That
-- way we still take advantage of the current value information while
-- scanning the actuals.
-- We suppress killing values if we are processing the nodes associated
-- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
-- type kills all the values as part of analyzing the code that
-- initializes the dispatch tables.
if Inside_Freezing_Actions = 0
and then (not Is_Library_Level_Entity (Nam)
or else Suppress_Value_Tracking_On_Call
(Nearest_Dynamic_Scope (Current_Scope)))
and then (Comes_From_Source (Nam)
or else (Present (Alias (Nam))
and then Comes_From_Source (Alias (Nam))))
then
Kill_Current_Values;
end if;
-- If we are warning about unread OUT parameters, this is the place to
-- set Last_Assignment for OUT and IN OUT parameters. We have to do this
-- after the above call to Kill_Current_Values (since that call clears
-- the Last_Assignment field of all local variables).
if (Warn_On_Modified_Unread or Warn_On_All_Unread_Out_Parameters)
and then Comes_From_Source (N)
and then In_Extended_Main_Source_Unit (N)
then
declare
F : Entity_Id;
A : Node_Id;
begin
F := First_Formal (Nam);
A := First_Actual (N);
while Present (F) and then Present (A) loop
if Ekind (F) in E_Out_Parameter | E_In_Out_Parameter
and then Warn_On_Modified_As_Out_Parameter (F)
and then Is_Entity_Name (A)
and then Present (Entity (A))
and then Comes_From_Source (N)
and then Safe_To_Capture_Value (N, Entity (A))
then
Set_Last_Assignment (Entity (A), A);
end if;
Next_Formal (F);
Next_Actual (A);
end loop;
end;
end if;
-- If the subprogram is a primitive operation, check whether or not
-- it is a correct dispatching call.
if Is_Overloadable (Nam)
and then Is_Dispatching_Operation (Nam)
then
Check_Dispatching_Call (N);
elsif Ekind (Nam) /= E_Subprogram_Type
and then Is_Abstract_Subprogram (Nam)
and then not In_Instance
then
Error_Msg_NE ("cannot call abstract subprogram &!", N, Nam);
end if;
-- If this is a dispatching call, generate the appropriate reference,
-- for better source navigation in GNAT Studio.
if Is_Overloadable (Nam)
and then Present (Controlling_Argument (N))
then
Generate_Reference (Nam, Subp, 'R');
-- Normal case, not a dispatching call: generate a call reference
else
Generate_Reference (Nam, Subp, 's');
end if;
if Is_Intrinsic_Subprogram (Nam) then
Check_Intrinsic_Call (N);
end if;
-- Check for violation of restriction No_Specific_Termination_Handlers
-- and warn on a potentially blocking call to Abort_Task.
if Restriction_Check_Required (No_Specific_Termination_Handlers)
and then (Is_RTE (Nam, RE_Set_Specific_Handler)
or else
Is_RTE (Nam, RE_Specific_Handler))
then
Check_Restriction (No_Specific_Termination_Handlers, N);
elsif Is_RTE (Nam, RE_Abort_Task) then
Check_Potentially_Blocking_Operation (N);
end if;
-- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
-- timing event violates restriction No_Relative_Delay (AI-0211). We
-- need to check the second argument to determine whether it is an
-- absolute or relative timing event.
if Restriction_Check_Required (No_Relative_Delay)
and then Is_RTE (Nam, RE_Set_Handler)
and then Is_RTE (Etype (Next_Actual (First_Actual (N))), RE_Time_Span)
then
Check_Restriction (No_Relative_Delay, N);
end if;
-- Issue an error for a call to an eliminated subprogram. This routine
-- will not perform the check if the call appears within a default
-- expression.
Check_For_Eliminated_Subprogram (Subp, Nam);
-- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
-- class-wide and the call dispatches on result in a context that does
-- not provide a tag, the call raises Program_Error.
if Nkind (N) = N_Function_Call
and then In_Instance
and then Is_Generic_Actual_Type (Typ)
and then Is_Class_Wide_Type (Typ)
and then Has_Controlling_Result (Nam)
and then Nkind (Parent (N)) = N_Object_Declaration
then
-- Verify that none of the formals are controlling
declare
Call_OK : Boolean := False;
F : Entity_Id;
begin
F := First_Formal (Nam);
while Present (F) loop
if Is_Controlling_Formal (F) then
Call_OK := True;
exit;
end if;
Next_Formal (F);
end loop;
if not Call_OK then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("!cannot determine tag of result<<", N);
Error_Msg_N ("\Program_Error [<<!", N);
Insert_Action (N,
Make_Raise_Program_Error (Sloc (N),
Reason => PE_Explicit_Raise));
end if;
end;
end if;
-- Check for calling a function with OUT or IN OUT parameter when the
-- calling context (us right now) is not Ada 2012, so does not allow
-- OUT or IN OUT parameters in function calls. Functions declared in
-- a predefined unit are OK, as they may be called indirectly from a
-- user-declared instantiation.
if Ada_Version < Ada_2012
and then Ekind (Nam) = E_Function
and then Has_Out_Or_In_Out_Parameter (Nam)
and then not In_Predefined_Unit (Nam)
then
Error_Msg_NE ("& has at least one OUT or `IN OUT` parameter", N, Nam);
Error_Msg_N ("\call to this function only allowed in Ada 2012", N);
end if;
-- Check the dimensions of the actuals in the call. For function calls,
-- propagate the dimensions from the returned type to N.
Analyze_Dimension_Call (N, Nam);
-- All done, evaluate call and deal with elaboration issues
Eval_Call (N);
if Legacy_Elaboration_Checks then
Check_Elab_Call (N);
end if;
-- Annotate the tree by creating a call marker in case the original call
-- is transformed by expansion. The call marker is automatically saved
-- for later examination by the ABE Processing phase.
Build_Call_Marker (N);
Mark_Use_Clauses (Subp);
Warn_On_Overlapping_Actuals (Nam, N);
-- Ada 202x (AI12-0075): If the call is a static call to a static
-- expression function, then we want to "inline" the call, replacing
-- it with the folded static result. This is not done if the checking
-- for a potentially static expression is enabled or if an error has
-- been posted on the call (which may be due to the check for recursive
-- calls, in which case we don't want to fall into infinite recursion
-- when doing the inlining).
if not Checking_Potentially_Static_Expression
and then Is_Static_Function_Call (N)
and then not Is_Intrinsic_Subprogram (Ultimate_Alias (Nam))
and then not Error_Posted (Ultimate_Alias (Nam))
then
Inline_Static_Function_Call (N, Ultimate_Alias (Nam));
-- In GNATprove mode, expansion is disabled, but we want to inline some
-- subprograms to facilitate formal verification. Indirect calls through
-- a subprogram type or within a generic cannot be inlined. Inlining is
-- performed only for calls subject to SPARK_Mode on.
elsif GNATprove_Mode
and then SPARK_Mode = On
and then Is_Overloadable (Nam)
and then not Inside_A_Generic
then
Nam_UA := Ultimate_Alias (Nam);
Nam_Decl := Unit_Declaration_Node (Nam_UA);
if Nkind (Nam_Decl) = N_Subprogram_Declaration then
Body_Id := Corresponding_Body (Nam_Decl);
-- Nothing to do if the subprogram is not eligible for inlining in
-- GNATprove mode, or inlining is disabled with switch -gnatdm
if not Is_Inlined_Always (Nam_UA)
or else not Can_Be_Inlined_In_GNATprove_Mode (Nam_UA, Body_Id)
or else Debug_Flag_M
then
null;
-- Calls cannot be inlined inside assertions, as GNATprove treats
-- assertions as logic expressions. Only issue a message when the
-- body has been seen, otherwise this leads to spurious messages
-- on expression functions.
elsif In_Assertion_Expr /= 0 then
Cannot_Inline
("cannot inline & (in assertion expression)?", N, Nam_UA,
Suppress_Info => No (Body_Id));
-- Calls cannot be inlined inside default expressions
elsif In_Default_Expr then
Cannot_Inline
("cannot inline & (in default expression)?", N, Nam_UA);
-- Calls cannot be inlined inside quantified expressions, which
-- are left in expression form for GNATprove. Since these
-- expressions are only preanalyzed, we need to detect the failure
-- to inline outside of the case for Full_Analysis below.
elsif In_Quantified_Expression (N) then
Cannot_Inline
("cannot inline & (in quantified expression)?", N, Nam_UA);
-- Inlining should not be performed during preanalysis
elsif Full_Analysis then
-- Do not inline calls inside expression functions or functions
-- generated by the front end for subtype predicates, as this
-- would prevent interpreting them as logical formulas in
-- GNATprove. Only issue a message when the body has been seen,
-- otherwise this leads to spurious messages on callees that
-- are themselves expression functions.
if Present (Current_Subprogram)
and then
(Is_Expression_Function_Or_Completion (Current_Subprogram)
or else Is_Predicate_Function (Current_Subprogram)
or else Is_Invariant_Procedure (Current_Subprogram)
or else Is_DIC_Procedure (Current_Subprogram))
then
if Present (Body_Id)
and then Present (Body_To_Inline (Nam_Decl))
then
if Is_Predicate_Function (Current_Subprogram) then
Cannot_Inline
("cannot inline & (inside predicate)?",
N, Nam_UA);
elsif Is_Invariant_Procedure (Current_Subprogram) then
Cannot_Inline
("cannot inline & (inside invariant)?",
N, Nam_UA);
elsif Is_DIC_Procedure (Current_Subprogram) then
Cannot_Inline
("cannot inline & (inside Default_Initial_Condition)?",
N, Nam_UA);
else
Cannot_Inline
("cannot inline & (inside expression function)?",
N, Nam_UA);
end if;
end if;
-- Cannot inline a call inside the definition of a record type,
-- typically inside the constraints of the type. Calls in
-- default expressions are also not inlined, but this is
-- filtered out above when testing In_Default_Expr.
elsif Is_Record_Type (Current_Scope) then
Cannot_Inline
("cannot inline & (inside record type)?", N, Nam_UA);
-- With the one-pass inlining technique, a call cannot be
-- inlined if the corresponding body has not been seen yet.
elsif No (Body_Id) then
Cannot_Inline
("cannot inline & (body not seen yet)?", N, Nam_UA);
-- Nothing to do if there is no body to inline, indicating that
-- the subprogram is not suitable for inlining in GNATprove
-- mode.
elsif No (Body_To_Inline (Nam_Decl)) then
null;
-- Calls cannot be inlined inside potentially unevaluated
-- expressions, as this would create complex actions inside
-- expressions, that are not handled by GNATprove.
elsif Is_Potentially_Unevaluated (N) then
Cannot_Inline
("cannot inline & (in potentially unevaluated context)?",
N, Nam_UA);
-- Calls cannot be inlined inside the conditions of while
-- loops, as this would create complex actions inside
-- the condition, that are not handled by GNATprove.
elsif In_While_Loop_Condition (N) then
Cannot_Inline
("cannot inline & (in while loop condition)?", N, Nam_UA);
-- Do not inline calls which would possibly lead to missing a
-- type conversion check on an input parameter.
elsif not Call_Can_Be_Inlined_In_GNATprove_Mode (N, Nam) then
Cannot_Inline
("cannot inline & (possible check on input parameters)?",
N, Nam_UA);
-- Otherwise, inline the call, issuing an info message when
-- -gnatd_f is set.
else
if Debug_Flag_Underscore_F then
Error_Msg_NE
("info: analyzing call to & in context?", N, Nam_UA);
end if;
Expand_Inlined_Call (N, Nam_UA, Nam);
end if;
end if;
end if;
end if;
end Resolve_Call;
-----------------------------
-- Resolve_Case_Expression --
-----------------------------
procedure Resolve_Case_Expression (N : Node_Id; Typ : Entity_Id) is
Alt : Node_Id;
Alt_Expr : Node_Id;
Alt_Typ : Entity_Id;
Is_Dyn : Boolean;
begin
Alt := First (Alternatives (N));
while Present (Alt) loop
Alt_Expr := Expression (Alt);
if Error_Posted (Alt_Expr) then
return;
end if;
Resolve (Alt_Expr, Typ);
Alt_Typ := Etype (Alt_Expr);
-- When the expression is of a scalar subtype different from the
-- result subtype, then insert a conversion to ensure the generation
-- of a constraint check.
if Is_Scalar_Type (Alt_Typ) and then Alt_Typ /= Typ then
Rewrite (Alt_Expr, Convert_To (Typ, Alt_Expr));
Analyze_And_Resolve (Alt_Expr, Typ);
end if;
Next (Alt);
end loop;
-- Apply RM 4.5.7 (17/3): whether the expression is statically or
-- dynamically tagged must be known statically.
if Is_Tagged_Type (Typ) and then not Is_Class_Wide_Type (Typ) then
Alt := First (Alternatives (N));
Is_Dyn := Is_Dynamically_Tagged (Expression (Alt));
while Present (Alt) loop
if Is_Dynamically_Tagged (Expression (Alt)) /= Is_Dyn then
Error_Msg_N
("all or none of the dependent expressions can be "
& "dynamically tagged", N);
end if;
Next (Alt);
end loop;
end if;
Set_Etype (N, Typ);
Eval_Case_Expression (N);
Analyze_Dimension (N);
end Resolve_Case_Expression;
-------------------------------
-- Resolve_Character_Literal --
-------------------------------
procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
C : Entity_Id;
begin
-- Verify that the character does belong to the type of the context
Set_Etype (N, B_Typ);
Eval_Character_Literal (N);
-- Wide_Wide_Character literals must always be defined, since the set
-- of wide wide character literals is complete, i.e. if a character
-- literal is accepted by the parser, then it is OK for wide wide
-- character (out of range character literals are rejected).
if Root_Type (B_Typ) = Standard_Wide_Wide_Character then
return;
-- Always accept character literal for type Any_Character, which
-- occurs in error situations and in comparisons of literals, both
-- of which should accept all literals.
elsif B_Typ = Any_Character then
return;
-- For Standard.Character or a type derived from it, check that the
-- literal is in range.
elsif Root_Type (B_Typ) = Standard_Character then
if In_Character_Range (UI_To_CC (Char_Literal_Value (N))) then
return;
end if;
-- For Standard.Wide_Character or a type derived from it, check that the
-- literal is in range.
elsif Root_Type (B_Typ) = Standard_Wide_Character then
if In_Wide_Character_Range (UI_To_CC (Char_Literal_Value (N))) then
return;
end if;
-- If the entity is already set, this has already been resolved in a
-- generic context, or comes from expansion. Nothing else to do.
elsif Present (Entity (N)) then
return;
-- Otherwise we have a user defined character type, and we can use the
-- standard visibility mechanisms to locate the referenced entity.
else
C := Current_Entity (N);
while Present (C) loop
if Etype (C) = B_Typ then
Set_Entity_With_Checks (N, C);
Generate_Reference (C, N);
return;
end if;
C := Homonym (C);
end loop;
end if;
-- If we fall through, then the literal does not match any of the
-- entries of the enumeration type. This isn't just a constraint error
-- situation, it is an illegality (see RM 4.2).
Error_Msg_NE
("character not defined for }", N, First_Subtype (B_Typ));
end Resolve_Character_Literal;
---------------------------
-- Resolve_Comparison_Op --
---------------------------
-- Context requires a boolean type, and plays no role in resolution.
-- Processing identical to that for equality operators. The result type is
-- the base type, which matters when pathological subtypes of booleans with
-- limited ranges are used.
procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id;
begin
-- If this is an intrinsic operation which is not predefined, use the
-- types of its declared arguments to resolve the possibly overloaded
-- operands. Otherwise the operands are unambiguous and specify the
-- expected type.
if Scope (Entity (N)) /= Standard_Standard then
T := Etype (First_Entity (Entity (N)));
else
T := Find_Unique_Type (L, R);
if T = Any_Fixed then
T := Unique_Fixed_Point_Type (L);
end if;
end if;
Set_Etype (N, Base_Type (Typ));
Generate_Reference (T, N, ' ');
-- Skip remaining processing if already set to Any_Type
if T = Any_Type then
return;
end if;
-- Deal with other error cases
if T = Any_String or else
T = Any_Composite or else
T = Any_Character
then
if T = Any_Character then
Ambiguous_Character (L);
else
Error_Msg_N ("ambiguous operands for comparison", N);
end if;
Set_Etype (N, Any_Type);
return;
end if;
-- Resolve the operands if types OK
Resolve (L, T);
Resolve (R, T);
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Generate_Operator_Reference (N, T);
Check_Low_Bound_Tested (N);
-- Check comparison on unordered enumeration
if Bad_Unordered_Enumeration_Reference (N, Etype (L)) then
Error_Msg_Sloc := Sloc (Etype (L));
Error_Msg_NE
("comparison on unordered enumeration type& declared#?U?",
N, Etype (L));
end if;
Analyze_Dimension (N);
Eval_Relational_Op (N);
end Resolve_Comparison_Op;
--------------------------------
-- Resolve_Declare_Expression --
--------------------------------
procedure Resolve_Declare_Expression
(N : Node_Id;
Typ : Entity_Id)
is
Decl : Node_Id;
Need_Transient_Scope : Boolean := False;
begin
-- Install the scope created for local declarations, if
-- any. The syntax allows a Declare_Expression with no
-- declarations, in analogy with block statements.
-- Note that that scope has no explicit declaration, but
-- appears as the scope of all entities declared therein.
Decl := First (Actions (N));
while Present (Decl) loop
exit when Nkind (Decl)
in N_Object_Declaration | N_Object_Renaming_Declaration;
Next (Decl);
end loop;
if Present (Decl) then
-- Need to establish a transient scope in case Expression (N)
-- requires actions to be wrapped.
declare
Node : Node_Id;
begin
Node := First (Actions (N));
while Present (Node) loop
if Nkind (Node) = N_Object_Declaration
and then Requires_Transient_Scope
(Etype (Defining_Identifier (Node)))
then
Need_Transient_Scope := True;
exit;
end if;
Next (Node);
end loop;
end;
if Need_Transient_Scope then
Establish_Transient_Scope (Decl, True);
else
Push_Scope (Scope (Defining_Identifier (Decl)));
end if;
declare
E : Entity_Id := First_Entity (Current_Scope);
begin
while Present (E) loop
Set_Current_Entity (E);
Set_Is_Immediately_Visible (E);
Next_Entity (E);
end loop;
end;
Resolve (Expression (N), Typ);
End_Scope;
else
Resolve (Expression (N), Typ);
end if;
end Resolve_Declare_Expression;
-----------------------------------------
-- Resolve_Discrete_Subtype_Indication --
-----------------------------------------
procedure Resolve_Discrete_Subtype_Indication
(N : Node_Id;
Typ : Entity_Id)
is
R : Node_Id;
S : Entity_Id;
begin
Analyze (Subtype_Mark (N));
S := Entity (Subtype_Mark (N));
if Nkind (Constraint (N)) /= N_Range_Constraint then
Error_Msg_N ("expect range constraint for discrete type", N);
Set_Etype (N, Any_Type);
else
R := Range_Expression (Constraint (N));
if R = Error then
return;
end if;
Analyze (R);
if Base_Type (S) /= Base_Type (Typ) then
Error_Msg_NE
("expect subtype of }", N, First_Subtype (Typ));
-- Rewrite the constraint as a range of Typ
-- to allow compilation to proceed further.
Set_Etype (N, Typ);
Rewrite (Low_Bound (R),
Make_Attribute_Reference (Sloc (Low_Bound (R)),
Prefix => New_Occurrence_Of (Typ, Sloc (R)),
Attribute_Name => Name_First));
Rewrite (High_Bound (R),
Make_Attribute_Reference (Sloc (High_Bound (R)),
Prefix => New_Occurrence_Of (Typ, Sloc (R)),
Attribute_Name => Name_First));
else
Resolve (R, Typ);
Set_Etype (N, Etype (R));
-- Additionally, we must check that the bounds are compatible
-- with the given subtype, which might be different from the
-- type of the context.
Apply_Range_Check (R, S);
-- ??? If the above check statically detects a Constraint_Error
-- it replaces the offending bound(s) of the range R with a
-- Constraint_Error node. When the itype which uses these bounds
-- is frozen the resulting call to Duplicate_Subexpr generates
-- a new temporary for the bounds.
-- Unfortunately there are other itypes that are also made depend
-- on these bounds, so when Duplicate_Subexpr is called they get
-- a forward reference to the newly created temporaries and Gigi
-- aborts on such forward references. This is probably sign of a
-- more fundamental problem somewhere else in either the order of
-- itype freezing or the way certain itypes are constructed.
-- To get around this problem we call Remove_Side_Effects right
-- away if either bounds of R are a Constraint_Error.
declare
L : constant Node_Id := Low_Bound (R);
H : constant Node_Id := High_Bound (R);
begin
if Nkind (L) = N_Raise_Constraint_Error then
Remove_Side_Effects (L);
end if;
if Nkind (H) = N_Raise_Constraint_Error then
Remove_Side_Effects (H);
end if;
end;
Check_Unset_Reference (Low_Bound (R));
Check_Unset_Reference (High_Bound (R));
end if;
end if;
end Resolve_Discrete_Subtype_Indication;
-------------------------
-- Resolve_Entity_Name --
-------------------------
-- Used to resolve identifiers and expanded names
procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id) is
function Is_Assignment_Or_Object_Expression
(Context : Node_Id;
Expr : Node_Id) return Boolean;
-- Determine whether node Context denotes an assignment statement or an
-- object declaration whose expression is node Expr.
function Is_Attribute_Expression (Expr : Node_Id) return Boolean;
-- Determine whether Expr is part of an N_Attribute_Reference
-- expression.
----------------------------------------
-- Is_Assignment_Or_Object_Expression --
----------------------------------------
function Is_Assignment_Or_Object_Expression
(Context : Node_Id;
Expr : Node_Id) return Boolean
is
begin
if Nkind (Context) in
N_Assignment_Statement | N_Object_Declaration
and then Expression (Context) = Expr
then
return True;
-- Check whether a construct that yields a name is the expression of
-- an assignment statement or an object declaration.
elsif (Nkind (Context) in N_Attribute_Reference
| N_Explicit_Dereference
| N_Indexed_Component
| N_Selected_Component
| N_Slice
and then Prefix (Context) = Expr)
or else
(Nkind (Context) in N_Type_Conversion
| N_Unchecked_Type_Conversion
and then Expression (Context) = Expr)
then
return
Is_Assignment_Or_Object_Expression
(Context => Parent (Context),
Expr => Context);
-- Otherwise the context is not an assignment statement or an object
-- declaration.
else
return False;
end if;
end Is_Assignment_Or_Object_Expression;
-----------------------------
-- Is_Attribute_Expression --
-----------------------------
function Is_Attribute_Expression (Expr : Node_Id) return Boolean is
N : Node_Id := Expr;
begin
while Present (N) loop
if Nkind (N) = N_Attribute_Reference then
return True;
end if;
N := Parent (N);
end loop;
return False;
end Is_Attribute_Expression;
-- Local variables
E : constant Entity_Id := Entity (N);
Par : Node_Id;
-- Start of processing for Resolve_Entity_Name
begin
-- If garbage from errors, set to Any_Type and return
if No (E) and then Total_Errors_Detected /= 0 then
Set_Etype (N, Any_Type);
return;
end if;
-- Replace named numbers by corresponding literals. Note that this is
-- the one case where Resolve_Entity_Name must reset the Etype, since
-- it is currently marked as universal.
if Ekind (E) = E_Named_Integer then
Set_Etype (N, Typ);
Eval_Named_Integer (N);
elsif Ekind (E) = E_Named_Real then
Set_Etype (N, Typ);
Eval_Named_Real (N);
-- For enumeration literals, we need to make sure that a proper style
-- check is done, since such literals are overloaded, and thus we did
-- not do a style check during the first phase of analysis.
elsif Ekind (E) = E_Enumeration_Literal then
Set_Entity_With_Checks (N, E);
Eval_Entity_Name (N);
-- Case of (sub)type name appearing in a context where an expression
-- is expected. This is legal if occurrence is a current instance.
-- See RM 8.6 (17/3).
elsif Is_Type (E) then
if Is_Current_Instance (N) then
null;
-- Any other use is an error
else
Error_Msg_N
("invalid use of subtype mark in expression or call", N);
end if;
-- Check discriminant use if entity is discriminant in current scope,
-- i.e. discriminant of record or concurrent type currently being
-- analyzed. Uses in corresponding body are unrestricted.
elsif Ekind (E) = E_Discriminant
and then Scope (E) = Current_Scope
and then not Has_Completion (Current_Scope)
then
Check_Discriminant_Use (N);
-- A parameterless generic function cannot appear in a context that
-- requires resolution.
elsif Ekind (E) = E_Generic_Function then
Error_Msg_N ("illegal use of generic function", N);
-- In Ada 83 an OUT parameter cannot be read, but attributes of
-- array types (i.e. bounds and length) are legal.
elsif Ekind (E) = E_Out_Parameter
and then (Is_Scalar_Type (Etype (E))
or else not Is_Attribute_Expression (Parent (N)))
and then (Nkind (Parent (N)) in N_Op
or else Nkind (Parent (N)) = N_Explicit_Dereference
or else Is_Assignment_Or_Object_Expression
(Context => Parent (N),
Expr => N))
then
if Ada_Version = Ada_83 then
Error_Msg_N ("(Ada 83) illegal reading of out parameter", N);
end if;
-- In all other cases, just do the possible static evaluation
else
-- A deferred constant that appears in an expression must have a
-- completion, unless it has been removed by in-place expansion of
-- an aggregate. A constant that is a renaming does not need
-- initialization.
if Ekind (E) = E_Constant
and then Comes_From_Source (E)
and then No (Constant_Value (E))
and then Is_Frozen (Etype (E))
and then not In_Spec_Expression
and then not Is_Imported (E)
and then Nkind (Parent (E)) /= N_Object_Renaming_Declaration
then
if No_Initialization (Parent (E))
or else (Present (Full_View (E))
and then No_Initialization (Parent (Full_View (E))))
then
null;
else
Error_Msg_N
("deferred constant is frozen before completion", N);
end if;
end if;
Eval_Entity_Name (N);
end if;
Par := Parent (N);
-- When the entity appears in a parameter association, retrieve the
-- related subprogram call.
if Nkind (Par) = N_Parameter_Association then
Par := Parent (Par);
end if;
if Comes_From_Source (N) then
-- The following checks are only relevant when SPARK_Mode is on as
-- they are not standard Ada legality rules.
if SPARK_Mode = On then
-- An effectively volatile object for reading must appear in
-- non-interfering context (SPARK RM 7.1.3(10)).
if Is_Object (E)
and then Is_Effectively_Volatile_For_Reading (E)
and then not Is_OK_Volatile_Context (Par, N)
then
SPARK_Msg_N
("volatile object cannot appear in this context "
& "(SPARK RM 7.1.3(10))", N);
end if;
-- Check for possible elaboration issues with respect to reads of
-- variables. The act of renaming the variable is not considered a
-- read as it simply establishes an alias.
if Legacy_Elaboration_Checks
and then Ekind (E) = E_Variable
and then Dynamic_Elaboration_Checks
and then Nkind (Par) /= N_Object_Renaming_Declaration
then
Check_Elab_Call (N);
end if;
end if;
-- The variable may eventually become a constituent of a single
-- protected/task type. Record the reference now and verify its
-- legality when analyzing the contract of the variable
-- (SPARK RM 9.3).
if Ekind (E) = E_Variable then
Record_Possible_Part_Of_Reference (E, N);
end if;
-- A Ghost entity must appear in a specific context
if Is_Ghost_Entity (E) then
Check_Ghost_Context (E, N);
end if;
end if;
-- We may be resolving an entity within expanded code, so a reference to
-- an entity should be ignored when calculating effective use clauses to
-- avoid inappropriate marking.
if Comes_From_Source (N) then
Mark_Use_Clauses (E);
end if;
end Resolve_Entity_Name;
-------------------
-- Resolve_Entry --
-------------------
procedure Resolve_Entry (Entry_Name : Node_Id) is
Loc : constant Source_Ptr := Sloc (Entry_Name);
Nam : Entity_Id;
New_N : Node_Id;
S : Entity_Id;
Tsk : Entity_Id;
E_Name : Node_Id;
Index : Node_Id;
function Actual_Index_Type (E : Entity_Id) return Entity_Id;
-- If the bounds of the entry family being called depend on task
-- discriminants, build a new index subtype where a discriminant is
-- replaced with the value of the discriminant of the target task.
-- The target task is the prefix of the entry name in the call.
-----------------------
-- Actual_Index_Type --
-----------------------
function Actual_Index_Type (E : Entity_Id) return Entity_Id is
Typ : constant Entity_Id := Entry_Index_Type (E);
Tsk : constant Entity_Id := Scope (E);
Lo : constant Node_Id := Type_Low_Bound (Typ);
Hi : constant Node_Id := Type_High_Bound (Typ);
New_T : Entity_Id;
function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id;
-- If the bound is given by a discriminant, replace with a reference
-- to the discriminant of the same name in the target task. If the
-- entry name is the target of a requeue statement and the entry is
-- in the current protected object, the bound to be used is the
-- discriminal of the object (see Apply_Range_Check for details of
-- the transformation).
-----------------------------
-- Actual_Discriminant_Ref --
-----------------------------
function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id is
Typ : constant Entity_Id := Etype (Bound);
Ref : Node_Id;
begin
Remove_Side_Effects (Bound);
if not Is_Entity_Name (Bound)
or else Ekind (Entity (Bound)) /= E_Discriminant
then
return Bound;
elsif Is_Protected_Type (Tsk)
and then In_Open_Scopes (Tsk)
and then Nkind (Parent (Entry_Name)) = N_Requeue_Statement
then
-- Note: here Bound denotes a discriminant of the corresponding
-- record type tskV, whose discriminal is a formal of the
-- init-proc tskVIP. What we want is the body discriminal,
-- which is associated to the discriminant of the original
-- concurrent type tsk.
return New_Occurrence_Of
(Find_Body_Discriminal (Entity (Bound)), Loc);
else
Ref :=
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Prefix (Prefix (Entry_Name))),
Selector_Name => New_Occurrence_Of (Entity (Bound), Loc));
Analyze (Ref);
Resolve (Ref, Typ);
return Ref;
end if;
end Actual_Discriminant_Ref;
-- Start of processing for Actual_Index_Type
begin
if not Has_Discriminants (Tsk)
or else (not Is_Entity_Name (Lo) and then not Is_Entity_Name (Hi))
then
return Entry_Index_Type (E);
else
New_T := Create_Itype (Ekind (Typ), Parent (Entry_Name));
Set_Etype (New_T, Base_Type (Typ));
Set_Size_Info (New_T, Typ);
Set_RM_Size (New_T, RM_Size (Typ));
Set_Scalar_Range (New_T,
Make_Range (Sloc (Entry_Name),
Low_Bound => Actual_Discriminant_Ref (Lo),
High_Bound => Actual_Discriminant_Ref (Hi)));
return New_T;
end if;
end Actual_Index_Type;
-- Start of processing for Resolve_Entry
begin
-- Find name of entry being called, and resolve prefix of name with its
-- own type. The prefix can be overloaded, and the name and signature of
-- the entry must be taken into account.
if Nkind (Entry_Name) = N_Indexed_Component then
-- Case of dealing with entry family within the current tasks
E_Name := Prefix (Entry_Name);
else
E_Name := Entry_Name;
end if;
if Is_Entity_Name (E_Name) then
-- Entry call to an entry (or entry family) in the current task. This
-- is legal even though the task will deadlock. Rewrite as call to
-- current task.
-- This can also be a call to an entry in an enclosing task. If this
-- is a single task, we have to retrieve its name, because the scope
-- of the entry is the task type, not the object. If the enclosing
-- task is a task type, the identity of the task is given by its own
-- self variable.
-- Finally this can be a requeue on an entry of the same task or
-- protected object.
S := Scope (Entity (E_Name));
for J in reverse 0 .. Scope_Stack.Last loop
if Is_Task_Type (Scope_Stack.Table (J).Entity)
and then not Comes_From_Source (S)
then
-- S is an enclosing task or protected object. The concurrent
-- declaration has been converted into a type declaration, and
-- the object itself has an object declaration that follows
-- the type in the same declarative part.
Tsk := Next_Entity (S);
while Etype (Tsk) /= S loop
Next_Entity (Tsk);
end loop;
S := Tsk;
exit;
elsif S = Scope_Stack.Table (J).Entity then
-- Call to current task. Will be transformed into call to Self
exit;
end if;
end loop;
New_N :=
Make_Selected_Component (Loc,
Prefix => New_Occurrence_Of (S, Loc),
Selector_Name =>
New_Occurrence_Of (Entity (E_Name), Loc));
Rewrite (E_Name, New_N);
Analyze (E_Name);
elsif Nkind (Entry_Name) = N_Selected_Component
and then Is_Overloaded (Prefix (Entry_Name))
then
-- Use the entry name (which must be unique at this point) to find
-- the prefix that returns the corresponding task/protected type.
declare
Pref : constant Node_Id := Prefix (Entry_Name);
Ent : constant Entity_Id := Entity (Selector_Name (Entry_Name));
I : Interp_Index;
It : Interp;
begin
Get_First_Interp (Pref, I, It);
while Present (It.Typ) loop
if Scope (Ent) = It.Typ then
Set_Etype (Pref, It.Typ);
exit;
end if;
Get_Next_Interp (I, It);
end loop;
end;
end if;
if Nkind (Entry_Name) = N_Selected_Component then
Resolve (Prefix (Entry_Name));
Resolve_Implicit_Dereference (Prefix (Entry_Name));
else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
Nam := Entity (Selector_Name (Prefix (Entry_Name)));
Resolve (Prefix (Prefix (Entry_Name)));
Resolve_Implicit_Dereference (Prefix (Prefix (Entry_Name)));
-- We do not resolve the prefix because an Entry_Family has no type,
-- although it has the semantics of an array since it can be indexed.
-- In order to perform the associated range check, we would need to
-- build an array type on the fly and set it on the prefix, but this
-- would be wasteful since only the index type matters. Therefore we
-- attach this index type directly, so that Actual_Index_Expression
-- can pick it up later in order to generate the range check.
Set_Etype (Prefix (Entry_Name), Actual_Index_Type (Nam));
Index := First (Expressions (Entry_Name));
Resolve (Index, Entry_Index_Type (Nam));
-- Generate a reference for the index when it denotes an entity
if Is_Entity_Name (Index) then
Generate_Reference (Entity (Index), Nam);
end if;
-- Up to this point the expression could have been the actual in a
-- simple entry call, and be given by a named association.
if Nkind (Index) = N_Parameter_Association then
Error_Msg_N ("expect expression for entry index", Index);
else
Apply_Scalar_Range_Check (Index, Etype (Prefix (Entry_Name)));
end if;
end if;
end Resolve_Entry;
------------------------
-- Resolve_Entry_Call --
------------------------
procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id) is
Entry_Name : constant Node_Id := Name (N);
Loc : constant Source_Ptr := Sloc (Entry_Name);
Nam : Entity_Id;
Norm_OK : Boolean;
Obj : Node_Id;
Was_Over : Boolean;
begin
-- We kill all checks here, because it does not seem worth the effort to
-- do anything better, an entry call is a big operation.
Kill_All_Checks;
-- Processing of the name is similar for entry calls and protected
-- operation calls. Once the entity is determined, we can complete
-- the resolution of the actuals.
-- The selector may be overloaded, in the case of a protected object
-- with overloaded functions. The type of the context is used for
-- resolution.
if Nkind (Entry_Name) = N_Selected_Component
and then Is_Overloaded (Selector_Name (Entry_Name))
and then Typ /= Standard_Void_Type
then
declare
I : Interp_Index;
It : Interp;
begin
Get_First_Interp (Selector_Name (Entry_Name), I, It);
while Present (It.Typ) loop
if Covers (Typ, It.Typ) then
Set_Entity (Selector_Name (Entry_Name), It.Nam);
Set_Etype (Entry_Name, It.Typ);
Generate_Reference (It.Typ, N, ' ');
end if;
Get_Next_Interp (I, It);
end loop;
end;
end if;
Resolve_Entry (Entry_Name);
if Nkind (Entry_Name) = N_Selected_Component then
-- Simple entry or protected operation call
Nam := Entity (Selector_Name (Entry_Name));
Obj := Prefix (Entry_Name);
if Is_Subprogram (Nam) then
Check_For_Eliminated_Subprogram (Entry_Name, Nam);
end if;
Was_Over := Is_Overloaded (Selector_Name (Entry_Name));
else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
-- Call to member of entry family
Nam := Entity (Selector_Name (Prefix (Entry_Name)));
Obj := Prefix (Prefix (Entry_Name));
Was_Over := Is_Overloaded (Selector_Name (Prefix (Entry_Name)));
end if;
-- We cannot in general check the maximum depth of protected entry calls
-- at compile time. But we can tell that any protected entry call at all
-- violates a specified nesting depth of zero.
if Is_Protected_Type (Scope (Nam)) then
Check_Restriction (Max_Entry_Queue_Length, N);
end if;
-- Use context type to disambiguate a protected function that can be
-- called without actuals and that returns an array type, and where the
-- argument list may be an indexing of the returned value.
if Ekind (Nam) = E_Function
and then Needs_No_Actuals (Nam)
and then Present (Parameter_Associations (N))
and then
((Is_Array_Type (Etype (Nam))
and then Covers (Typ, Component_Type (Etype (Nam))))
or else (Is_Access_Type (Etype (Nam))
and then Is_Array_Type (Designated_Type (Etype (Nam)))
and then
Covers
(Typ,
Component_Type (Designated_Type (Etype (Nam))))))
then
declare
Index_Node : Node_Id;
begin
Index_Node :=
Make_Indexed_Component (Loc,
Prefix =>
Make_Function_Call (Loc, Name => Relocate_Node (Entry_Name)),
Expressions => Parameter_Associations (N));
-- Since we are correcting a node classification error made by the
-- parser, we call Replace rather than Rewrite.
Replace (N, Index_Node);
Set_Etype (Prefix (N), Etype (Nam));
Set_Etype (N, Typ);
Resolve_Indexed_Component (N, Typ);
return;
end;
end if;
if Is_Entry (Nam)
and then Present (Contract_Wrapper (Nam))
and then Current_Scope /= Contract_Wrapper (Nam)
then
-- Note the entity being called before rewriting the call, so that
-- it appears used at this point.
Generate_Reference (Nam, Entry_Name, 'r');
-- Rewrite as call to the precondition wrapper, adding the task
-- object to the list of actuals. If the call is to a member of an
-- entry family, include the index as well.
declare
New_Call : Node_Id;
New_Actuals : List_Id;
begin
New_Actuals := New_List (Obj);
if Nkind (Entry_Name) = N_Indexed_Component then
Append_To (New_Actuals,
New_Copy_Tree (First (Expressions (Entry_Name))));
end if;
Append_List (Parameter_Associations (N), New_Actuals);
New_Call :=
Make_Procedure_Call_Statement (Loc,
Name =>
New_Occurrence_Of (Contract_Wrapper (Nam), Loc),
Parameter_Associations => New_Actuals);
Rewrite (N, New_Call);
-- Preanalyze and resolve new call. Current procedure is called
-- from Resolve_Call, after which expansion will take place.
Preanalyze_And_Resolve (N);
return;
end;
end if;
-- The operation name may have been overloaded. Order the actuals
-- according to the formals of the resolved entity, and set the return
-- type to that of the operation.
if Was_Over then
Normalize_Actuals (N, Nam, False, Norm_OK);
pragma Assert (Norm_OK);
Set_Etype (N, Etype (Nam));
-- Reset the Is_Overloaded flag, since resolution is now completed
-- Simple entry call
if Nkind (Entry_Name) = N_Selected_Component then
Set_Is_Overloaded (Selector_Name (Entry_Name), False);
-- Call to a member of an entry family
else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
Set_Is_Overloaded (Selector_Name (Prefix (Entry_Name)), False);
end if;
end if;
Resolve_Actuals (N, Nam);
Check_Internal_Protected_Use (N, Nam);
-- Create a call reference to the entry
Generate_Reference (Nam, Entry_Name, 's');
if Is_Entry (Nam) then
Check_Potentially_Blocking_Operation (N);
end if;
-- Verify that a procedure call cannot masquerade as an entry
-- call where an entry call is expected.
if Ekind (Nam) = E_Procedure then
if Nkind (Parent (N)) = N_Entry_Call_Alternative
and then N = Entry_Call_Statement (Parent (N))
then
Error_Msg_N ("entry call required in select statement", N);
elsif Nkind (Parent (N)) = N_Triggering_Alternative
and then N = Triggering_Statement (Parent (N))
then
Error_Msg_N ("triggering statement cannot be procedure call", N);
elsif Ekind (Scope (Nam)) = E_Task_Type
and then not In_Open_Scopes (Scope (Nam))
then
Error_Msg_N ("task has no entry with this name", Entry_Name);
end if;
end if;
-- After resolution, entry calls and protected procedure calls are
-- changed into entry calls, for expansion. The structure of the node
-- does not change, so it can safely be done in place. Protected
-- function calls must keep their structure because they are
-- subexpressions.
if Ekind (Nam) /= E_Function then
-- A protected operation that is not a function may modify the
-- corresponding object, and cannot apply to a constant. If this
-- is an internal call, the prefix is the type itself.
if Is_Protected_Type (Scope (Nam))
and then not Is_Variable (Obj)
and then (not Is_Entity_Name (Obj)
or else not Is_Type (Entity (Obj)))
then
Error_Msg_N
("prefix of protected procedure or entry call must be variable",
Entry_Name);
end if;
declare
Entry_Call : Node_Id;
begin
Entry_Call :=
Make_Entry_Call_Statement (Loc,
Name => Entry_Name,
Parameter_Associations => Parameter_Associations (N));
-- Inherit relevant attributes from the original call
Set_First_Named_Actual
(Entry_Call, First_Named_Actual (N));
Set_Is_Elaboration_Checks_OK_Node
(Entry_Call, Is_Elaboration_Checks_OK_Node (N));
Set_Is_Elaboration_Warnings_OK_Node
(Entry_Call, Is_Elaboration_Warnings_OK_Node (N));
Set_Is_SPARK_Mode_On_Node
(Entry_Call, Is_SPARK_Mode_On_Node (N));
Rewrite (N, Entry_Call);
Set_Analyzed (N, True);
end;
-- Protected functions can return on the secondary stack, in which case
-- we must trigger the transient scope mechanism.
elsif Expander_Active
and then Requires_Transient_Scope (Etype (Nam))
then
Establish_Transient_Scope (N, Manage_Sec_Stack => True);
end if;
-- Now we know that this is not a call to a function that returns an
-- array type; moreover, we know the name of the called entry. Detect
-- overlapping actuals, just like for a subprogram call.
Warn_On_Overlapping_Actuals (Nam, N);
end Resolve_Entry_Call;
-------------------------
-- Resolve_Equality_Op --
-------------------------
-- Both arguments must have the same type, and the boolean context does
-- not participate in the resolution. The first pass verifies that the
-- interpretation is not ambiguous, and the type of the left argument is
-- correctly set, or is Any_Type in case of ambiguity. If both arguments
-- are strings or aggregates, allocators, or Null, they are ambiguous even
-- though they carry a single (universal) type. Diagnose this case here.
procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id := Find_Unique_Type (L, R);
procedure Check_If_Expression (Cond : Node_Id);
-- The resolution rule for if expressions requires that each such must
-- have a unique type. This means that if several dependent expressions
-- are of a non-null anonymous access type, and the context does not
-- impose an expected type (as can be the case in an equality operation)
-- the expression must be rejected.
procedure Explain_Redundancy (N : Node_Id);
-- Attempt to explain the nature of a redundant comparison with True. If
-- the expression N is too complex, this routine issues a general error
-- message.
function Find_Unique_Access_Type return Entity_Id;
-- In the case of allocators and access attributes, the context must
-- provide an indication of the specific access type to be used. If
-- one operand is of such a "generic" access type, check whether there
-- is a specific visible access type that has the same designated type.
-- This is semantically dubious, and of no interest to any real code,
-- but c48008a makes it all worthwhile.
function Suspicious_Prio_For_Equality return Boolean;
-- Returns True iff the parent node is a and/or/xor operation that
-- could be the cause of confused priorities. Note that if the not is
-- in parens, then False is returned.
-------------------------
-- Check_If_Expression --
-------------------------
procedure Check_If_Expression (Cond : Node_Id) is
Then_Expr : Node_Id;
Else_Expr : Node_Id;
begin
if Nkind (Cond) = N_If_Expression then
Then_Expr := Next (First (Expressions (Cond)));
Else_Expr := Next (Then_Expr);
if Nkind (Then_Expr) /= N_Null
and then Nkind (Else_Expr) /= N_Null
then
Error_Msg_N ("cannot determine type of if expression", Cond);
end if;
end if;
end Check_If_Expression;
------------------------
-- Explain_Redundancy --
------------------------
procedure Explain_Redundancy (N : Node_Id) is
Error : Name_Id;
Val : Node_Id;
Val_Id : Entity_Id;
begin
Val := N;
-- Strip the operand down to an entity
loop
if Nkind (Val) = N_Selected_Component then
Val := Selector_Name (Val);
else
exit;
end if;
end loop;
-- The construct denotes an entity
if Is_Entity_Name (Val) and then Present (Entity (Val)) then
Val_Id := Entity (Val);
-- Do not generate an error message when the comparison is done
-- against the enumeration literal Standard.True.
if Ekind (Val_Id) /= E_Enumeration_Literal then
-- Build a customized error message
Name_Len := 0;
Add_Str_To_Name_Buffer ("?r?");
if Ekind (Val_Id) = E_Component then
Add_Str_To_Name_Buffer ("component ");
elsif Ekind (Val_Id) = E_Constant then
Add_Str_To_Name_Buffer ("constant ");
elsif Ekind (Val_Id) = E_Discriminant then
Add_Str_To_Name_Buffer ("discriminant ");
elsif Is_Formal (Val_Id) then
Add_Str_To_Name_Buffer ("parameter ");
elsif Ekind (Val_Id) = E_Variable then
Add_Str_To_Name_Buffer ("variable ");
end if;
Add_Str_To_Name_Buffer ("& is always True!");
Error := Name_Find;
Error_Msg_NE (Get_Name_String (Error), Val, Val_Id);
end if;
-- The construct is too complex to disect, issue a general message
else
Error_Msg_N ("?r?expression is always True!", Val);
end if;
end Explain_Redundancy;
-----------------------------
-- Find_Unique_Access_Type --
-----------------------------
function Find_Unique_Access_Type return Entity_Id is
Acc : Entity_Id;
E : Entity_Id;
S : Entity_Id;
begin
if Ekind (Etype (R)) in E_Allocator_Type | E_Access_Attribute_Type
then
Acc := Designated_Type (Etype (R));
elsif Ekind (Etype (L)) in E_Allocator_Type | E_Access_Attribute_Type
then
Acc := Designated_Type (Etype (L));
else
return Empty;
end if;
S := Current_Scope;
while S /= Standard_Standard loop
E := First_Entity (S);
while Present (E) loop
if Is_Type (E)
and then Is_Access_Type (E)
and then Ekind (E) /= E_Allocator_Type
and then Designated_Type (E) = Base_Type (Acc)
then
return E;
end if;
Next_Entity (E);
end loop;
S := Scope (S);
end loop;
return Empty;
end Find_Unique_Access_Type;
----------------------------------
-- Suspicious_Prio_For_Equality --
----------------------------------
function Suspicious_Prio_For_Equality return Boolean is
Par : constant Node_Id := Parent (N);
begin
-- Check if parent node is one of and/or/xor, not parenthesized
-- explicitly, and its own parent is not of this kind. Otherwise,
-- it's a case of chained Boolean conditions which is likely well
-- parenthesized.
if Nkind (Par) in N_Op_And | N_Op_Or | N_Op_Xor
and then Paren_Count (N) = 0
and then Nkind (Parent (Par)) not in N_Op_And | N_Op_Or | N_Op_Xor
then
declare
Compar : Node_Id :=
(if Left_Opnd (Par) = N then
Right_Opnd (Par)
else
Left_Opnd (Par));
begin
-- Compar may have been rewritten, for example from (a /= b)
-- into not (a = b). Use the Original_Node instead.
Compar := Original_Node (Compar);
-- If the other argument of the and/or/xor is also a
-- comparison, or another and/or/xor then most likely
-- the priorities are correctly set.
return Nkind (Compar) not in N_Op_Boolean;
end;
else
return False;
end if;
end Suspicious_Prio_For_Equality;
-- Start of processing for Resolve_Equality_Op
begin
Set_Etype (N, Base_Type (Typ));
Generate_Reference (T, N, ' ');
if T = Any_Fixed then
T := Unique_Fixed_Point_Type (L);
end if;
if T /= Any_Type then
if T = Any_String or else
T = Any_Composite or else
T = Any_Character
then
if T = Any_Character then
Ambiguous_Character (L);
else
Error_Msg_N ("ambiguous operands for equality", N);
end if;
Set_Etype (N, Any_Type);
return;
elsif T = Any_Access
or else Ekind (T) in E_Allocator_Type | E_Access_Attribute_Type
then
T := Find_Unique_Access_Type;
if No (T) then
Error_Msg_N ("ambiguous operands for equality", N);
Set_Etype (N, Any_Type);
return;
end if;
-- If expressions must have a single type, and if the context does
-- not impose one the dependent expressions cannot be anonymous
-- access types.
-- Why no similar processing for case expressions???
elsif Ada_Version >= Ada_2012
and then Is_Anonymous_Access_Type (Etype (L))
and then Is_Anonymous_Access_Type (Etype (R))
then
Check_If_Expression (L);
Check_If_Expression (R);
end if;
Resolve (L, T);
Resolve (R, T);
-- If the unique type is a class-wide type then it will be expanded
-- into a dispatching call to the predefined primitive. Therefore we
-- check here for potential violation of such restriction.
if Is_Class_Wide_Type (T) then
Check_Restriction (No_Dispatching_Calls, N);
end if;
-- Only warn for redundant equality comparison to True for objects
-- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
-- other expressions, it may be a matter of preference to write
-- "Expr = True" or "Expr".
if Warn_On_Redundant_Constructs
and then Comes_From_Source (N)
and then Comes_From_Source (R)
and then Is_Entity_Name (R)
and then Entity (R) = Standard_True
and then
((Is_Entity_Name (L) and then Is_Object (Entity (L)))
or else
Nkind (L) in N_Op)
then
Error_Msg_N -- CODEFIX
("?r?comparison with True is redundant!", N);
Explain_Redundancy (Original_Node (R));
end if;
-- Warn on a (in)equality between boolean values which is not
-- parenthesized when the parent expression is one of and/or/xor, as
-- this is interpreted as (a = b) op c where most likely a = (b op c)
-- was intended. Do not generate a warning in generic instances, as
-- the problematic expression may be implicitly parenthesized in
-- the generic itself if one of the operators is a generic formal.
-- Also do not generate a warning for generated equality, for
-- example from rewritting a membership test.
if Warn_On_Questionable_Missing_Parens
and then not In_Instance
and then Comes_From_Source (N)
and then Is_Boolean_Type (T)
and then Suspicious_Prio_For_Equality
then
Error_Msg_N ("?q?equality should be parenthesized here!", N);
end if;
-- If the equality is overloaded and the operands have resolved
-- properly, set the proper equality operator on the node. The
-- current setting is the first one found during analysis, which
-- is not necessarily the one to which the node has resolved.
if Is_Overloaded (N) then
declare
I : Interp_Index;
It : Interp;
begin
Get_First_Interp (N, I, It);
-- If the equality is user-defined, the type of the operands
-- matches that of the formals. For a predefined operator,
-- it is the scope that matters, given that the predefined
-- equality has Any_Type formals. In either case the result
-- type (most often Boolean) must match the context. The scope
-- is either that of the type, if there is a generated equality
-- (when there is an equality for the component type), or else
-- Standard otherwise.
while Present (It.Typ) loop
if Etype (It.Nam) = Typ
and then
(Etype (First_Entity (It.Nam)) = Etype (L)
or else Scope (It.Nam) = Standard_Standard
or else Scope (It.Nam) = Scope (T))
then
Set_Entity (N, It.Nam);
Set_Is_Overloaded (N, False);
exit;
end if;
Get_Next_Interp (I, It);
end loop;
-- If expansion is active and this is an inherited operation,
-- replace it with its ancestor. This must not be done during
-- preanalysis because the type may not be frozen yet, as when
-- the context is a precondition or postcondition.
if Present (Alias (Entity (N))) and then Expander_Active then
Set_Entity (N, Alias (Entity (N)));
end if;
end;
end if;
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Generate_Operator_Reference (N, T);
Check_Low_Bound_Tested (N);
-- If this is an inequality, it may be the implicit inequality
-- created for a user-defined operation, in which case the corres-
-- ponding equality operation is not intrinsic, and the operation
-- cannot be constant-folded. Else fold.
if Nkind (N) = N_Op_Eq
or else Comes_From_Source (Entity (N))
or else Ekind (Entity (N)) = E_Operator
or else Is_Intrinsic_Subprogram
(Corresponding_Equality (Entity (N)))
then
Analyze_Dimension (N);
Eval_Relational_Op (N);
elsif Nkind (N) = N_Op_Ne
and then Is_Abstract_Subprogram (Entity (N))
then
Error_Msg_NE ("cannot call abstract subprogram &!", N, Entity (N));
end if;
-- Ada 2005: If one operand is an anonymous access type, convert the
-- other operand to it, to ensure that the underlying types match in
-- the back-end. Same for access_to_subprogram, and the conversion
-- verifies that the types are subtype conformant.
-- We apply the same conversion in the case one of the operands is a
-- private subtype of the type of the other.
-- Why the Expander_Active test here ???
if Expander_Active
and then
(Ekind (T) in E_Anonymous_Access_Type
| E_Anonymous_Access_Subprogram_Type
or else Is_Private_Type (T))
then
if Etype (L) /= T then
Rewrite (L,
Make_Unchecked_Type_Conversion (Sloc (L),
Subtype_Mark => New_Occurrence_Of (T, Sloc (L)),
Expression => Relocate_Node (L)));
Analyze_And_Resolve (L, T);
end if;
if (Etype (R)) /= T then
Rewrite (R,
Make_Unchecked_Type_Conversion (Sloc (R),
Subtype_Mark => New_Occurrence_Of (Etype (L), Sloc (R)),
Expression => Relocate_Node (R)));
Analyze_And_Resolve (R, T);
end if;
end if;
end if;
end Resolve_Equality_Op;
----------------------------------
-- Resolve_Explicit_Dereference --
----------------------------------
procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
New_N : Node_Id;
P : constant Node_Id := Prefix (N);
P_Typ : Entity_Id;
-- The candidate prefix type, if overloaded
I : Interp_Index;
It : Interp;
begin
Check_Fully_Declared_Prefix (Typ, P);
P_Typ := Empty;
-- A useful optimization: check whether the dereference denotes an
-- element of a container, and if so rewrite it as a call to the
-- corresponding Element function.
-- Disabled for now, on advice of ARG. A more restricted form of the
-- predicate might be acceptable ???
-- if Is_Container_Element (N) then
-- return;
-- end if;
if Is_Overloaded (P) then
-- Use the context type to select the prefix that has the correct
-- designated type. Keep the first match, which will be the inner-
-- most.
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
if Is_Access_Type (It.Typ)
and then Covers (Typ, Designated_Type (It.Typ))
then
if No (P_Typ) then
P_Typ := It.Typ;
end if;
-- Remove access types that do not match, but preserve access
-- to subprogram interpretations, in case a further dereference
-- is needed (see below).
elsif Ekind (It.Typ) /= E_Access_Subprogram_Type then
Remove_Interp (I);
end if;
Get_Next_Interp (I, It);
end loop;
if Present (P_Typ) then
Resolve (P, P_Typ);
Set_Etype (N, Designated_Type (P_Typ));
else
-- If no interpretation covers the designated type of the prefix,
-- this is the pathological case where not all implementations of
-- the prefix allow the interpretation of the node as a call. Now
-- that the expected type is known, Remove other interpretations
-- from prefix, rewrite it as a call, and resolve again, so that
-- the proper call node is generated.
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
if Ekind (It.Typ) /= E_Access_Subprogram_Type then
Remove_Interp (I);
end if;
Get_Next_Interp (I, It);
end loop;
New_N :=
Make_Function_Call (Loc,
Name =>
Make_Explicit_Dereference (Loc,
Prefix => P),
Parameter_Associations => New_List);
Save_Interps (N, New_N);
Rewrite (N, New_N);
Analyze_And_Resolve (N, Typ);
return;
end if;
-- If not overloaded, resolve P with its own type
else
Resolve (P);
end if;
-- If the prefix might be null, add an access check
if Is_Access_Type (Etype (P))
and then not Can_Never_Be_Null (Etype (P))
then
Apply_Access_Check (N);
end if;
-- If the designated type is a packed unconstrained array type, and the
-- explicit dereference is not in the context of an attribute reference,
-- then we must compute and set the actual subtype, since it is needed
-- by Gigi. The reason we exclude the attribute case is that this is
-- handled fine by Gigi, and in fact we use such attributes to build the
-- actual subtype. We also exclude generated code (which builds actual
-- subtypes directly if they are needed).
if Is_Packed_Array (Etype (N))
and then not Is_Constrained (Etype (N))
and then Nkind (Parent (N)) /= N_Attribute_Reference
and then Comes_From_Source (N)
then
Set_Etype (N, Get_Actual_Subtype (N));
end if;
Analyze_Dimension (N);
-- Note: No Eval processing is required for an explicit dereference,
-- because such a name can never be static.
end Resolve_Explicit_Dereference;
-------------------------------------
-- Resolve_Expression_With_Actions --
-------------------------------------
procedure Resolve_Expression_With_Actions (N : Node_Id; Typ : Entity_Id) is
function OK_For_Static (Act : Node_Id) return Boolean;
-- True if Act is an action of a declare_expression that is allowed in a
-- static declare_expression.
function All_OK_For_Static return Boolean;
-- True if all actions of N are allowed in a static declare_expression.
function Get_Literal (Expr : Node_Id) return Node_Id;
-- Expr is an expression with compile-time-known value. This returns the
-- literal node that reprsents that value.
function OK_For_Static (Act : Node_Id) return Boolean is
begin
case Nkind (Act) is
when N_Object_Declaration =>
if Constant_Present (Act)
and then Is_Static_Expression (Expression (Act))
then
return True;
end if;
when N_Object_Renaming_Declaration =>
if Statically_Names_Object (Name (Act)) then
return True;
end if;
when others =>
-- No other declarations, nor even pragmas, are allowed in a
-- declare expression, so if we see something else, it must be
-- an internally generated expression_with_actions.
null;
end case;
return False;
end OK_For_Static;
function All_OK_For_Static return Boolean is
Act : Node_Id := First (Actions (N));
begin
while Present (Act) loop
if not OK_For_Static (Act) then
return False;
end if;
Next (Act);
end loop;
return True;
end All_OK_For_Static;
function Get_Literal (Expr : Node_Id) return Node_Id is
pragma Assert (Compile_Time_Known_Value (Expr));
Result : Node_Id;
begin
case Nkind (Expr) is
when N_Has_Entity =>
if Ekind (Entity (Expr)) = E_Enumeration_Literal then
Result := Expr;
else
Result := Constant_Value (Entity (Expr));
end if;
when N_Numeric_Or_String_Literal =>
Result := Expr;
when others =>
raise Program_Error;
end case;
pragma Assert
(Nkind (Result) in N_Numeric_Or_String_Literal
or else Ekind (Entity (Result)) = E_Enumeration_Literal);
return Result;
end Get_Literal;
Loc : constant Source_Ptr := Sloc (N);
begin
Set_Etype (N, Typ);
if Is_Empty_List (Actions (N)) then
pragma Assert (All_OK_For_Static); null;
end if;
-- If the value of the expression is known at compile time, and all
-- of the actions (if any) are suitable, then replace the declare
-- expression with its expression. This allows the declare expression
-- as a whole to be static if appropriate. See AI12-0368.
if Compile_Time_Known_Value (Expression (N)) then
if Is_Empty_List (Actions (N)) then
Rewrite (N, Expression (N));
elsif All_OK_For_Static then
Rewrite
(N, New_Copy_Tree
(Get_Literal (Expression (N)), New_Sloc => Loc));
end if;
end if;
end Resolve_Expression_With_Actions;
----------------------------------
-- Resolve_Generalized_Indexing --
----------------------------------
procedure Resolve_Generalized_Indexing (N : Node_Id; Typ : Entity_Id) is
Indexing : constant Node_Id := Generalized_Indexing (N);
begin
Rewrite (N, Indexing);
Resolve (N, Typ);
end Resolve_Generalized_Indexing;
---------------------------
-- Resolve_If_Expression --
---------------------------
procedure Resolve_If_Expression (N : Node_Id; Typ : Entity_Id) is
procedure Apply_Check (Expr : Node_Id);
-- When a dependent expression is of a subtype different from
-- the context subtype, then insert a qualification to ensure
-- the generation of a constraint check. This was previously
-- for scalar types. For array types apply a length check, given
-- that the context in general allows sliding, while a qualified
-- expression forces equality of bounds.
-----------------
-- Apply_Check --
-----------------
procedure Apply_Check (Expr : Node_Id) is
Expr_Typ : constant Entity_Id := Etype (Expr);
Loc : constant Source_Ptr := Sloc (Expr);
begin
if Expr_Typ = Typ
or else Is_Tagged_Type (Typ)
or else Is_Access_Type (Typ)
or else not Is_Constrained (Typ)
or else Inside_A_Generic
then
null;
elsif Is_Array_Type (Typ) then
Apply_Length_Check (Expr, Typ);
else
Rewrite (Expr,
Make_Qualified_Expression (Loc,
Subtype_Mark => New_Occurrence_Of (Typ, Loc),
Expression => Relocate_Node (Expr)));
Analyze_And_Resolve (Expr, Typ);
end if;
end Apply_Check;
-- Local variables
Condition : constant Node_Id := First (Expressions (N));
Else_Expr : Node_Id;
Then_Expr : Node_Id;
-- Start of processing for Resolve_If_Expression
begin
-- Defend against malformed expressions
if No (Condition) then
return;
end if;
Then_Expr := Next (Condition);
if No (Then_Expr) then
return;
end if;
Else_Expr := Next (Then_Expr);
Resolve (Condition, Any_Boolean);
Resolve (Then_Expr, Typ);
Apply_Check (Then_Expr);
-- If ELSE expression present, just resolve using the determined type
-- If type is universal, resolve to any member of the class.
if Present (Else_Expr) then
if Typ = Universal_Integer then
Resolve (Else_Expr, Any_Integer);
elsif Typ = Universal_Real then
Resolve (Else_Expr, Any_Real);
else
Resolve (Else_Expr, Typ);
end if;
Apply_Check (Else_Expr);
-- Apply RM 4.5.7 (17/3): whether the expression is statically or
-- dynamically tagged must be known statically.
if Is_Tagged_Type (Typ) and then not Is_Class_Wide_Type (Typ) then
if Is_Dynamically_Tagged (Then_Expr) /=
Is_Dynamically_Tagged (Else_Expr)
then
Error_Msg_N ("all or none of the dependent expressions "
& "can be dynamically tagged", N);
end if;
end if;
-- If no ELSE expression is present, root type must be Standard.Boolean
-- and we provide a Standard.True result converted to the appropriate
-- Boolean type (in case it is a derived boolean type).
elsif Root_Type (Typ) = Standard_Boolean then
Else_Expr :=
Convert_To (Typ, New_Occurrence_Of (Standard_True, Sloc (N)));
Analyze_And_Resolve (Else_Expr, Typ);
Append_To (Expressions (N), Else_Expr);
else
Error_Msg_N ("can only omit ELSE expression in Boolean case", N);
Append_To (Expressions (N), Error);
end if;
Set_Etype (N, Typ);
if not Error_Posted (N) then
Eval_If_Expression (N);
end if;
Analyze_Dimension (N);
end Resolve_If_Expression;
----------------------------------
-- Resolve_Implicit_Dereference --
----------------------------------
procedure Resolve_Implicit_Dereference (P : Node_Id) is
Desig_Typ : Entity_Id;
begin
-- In an instance the proper view may not always be correct for
-- private types, see e.g. Sem_Type.Covers for similar handling.
if Is_Private_Type (Etype (P))
and then Present (Full_View (Etype (P)))
and then Is_Access_Type (Full_View (Etype (P)))
and then In_Instance
then
Set_Etype (P, Full_View (Etype (P)));
end if;
if Is_Access_Type (Etype (P)) then
Desig_Typ := Implicitly_Designated_Type (Etype (P));
Insert_Explicit_Dereference (P);
Analyze_And_Resolve (P, Desig_Typ);
end if;
end Resolve_Implicit_Dereference;
-------------------------------
-- Resolve_Indexed_Component --
-------------------------------
procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id) is
Name : constant Node_Id := Prefix (N);
Expr : Node_Id;
Array_Type : Entity_Id := Empty; -- to prevent junk warning
Index : Node_Id;
begin
if Present (Generalized_Indexing (N)) then
Resolve_Generalized_Indexing (N, Typ);
return;
end if;
if Is_Overloaded (Name) then
-- Use the context type to select the prefix that yields the correct
-- component type.
declare
I : Interp_Index;
It : Interp;
I1 : Interp_Index := 0;
P : constant Node_Id := Prefix (N);
Found : Boolean := False;
begin
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
if (Is_Array_Type (It.Typ)
and then Covers (Typ, Component_Type (It.Typ)))
or else (Is_Access_Type (It.Typ)
and then Is_Array_Type (Designated_Type (It.Typ))
and then
Covers
(Typ,
Component_Type (Designated_Type (It.Typ))))
then
if Found then
It := Disambiguate (P, I1, I, Any_Type);
if It = No_Interp then
Error_Msg_N ("ambiguous prefix for indexing", N);
Set_Etype (N, Typ);
return;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
end if;
Get_Next_Interp (I, It);
end loop;
end;
else
Array_Type := Etype (Name);
end if;
Resolve (Name, Array_Type);
Array_Type := Get_Actual_Subtype_If_Available (Name);
-- If the prefix's type is an access type, get to the real array type.
-- Note: we do not apply an access check because an explicit dereference
-- will be introduced later, and the check will happen there.
if Is_Access_Type (Array_Type) then
Array_Type := Implicitly_Designated_Type (Array_Type);
end if;
-- If name was overloaded, set component type correctly now.
-- If a misplaced call to an entry family (which has no index types)
-- return. Error will be diagnosed from calling context.
if Is_Array_Type (Array_Type) then
Set_Etype (N, Component_Type (Array_Type));
else
return;
end if;
Index := First_Index (Array_Type);
Expr := First (Expressions (N));
-- The prefix may have resolved to a string literal, in which case its
-- etype has a special representation. This is only possible currently
-- if the prefix is a static concatenation, written in functional
-- notation.
if Ekind (Array_Type) = E_String_Literal_Subtype then
Resolve (Expr, Standard_Positive);
else
while Present (Index) and then Present (Expr) loop
Resolve (Expr, Etype (Index));
Check_Unset_Reference (Expr);
Apply_Scalar_Range_Check (Expr, Etype (Index));
Next_Index (Index);
Next (Expr);
end loop;
end if;
Resolve_Implicit_Dereference (Prefix (N));
Analyze_Dimension (N);
-- Do not generate the warning on suspicious index if we are analyzing
-- package Ada.Tags; otherwise we will report the warning with the
-- Prims_Ptr field of the dispatch table.
if Scope (Etype (Prefix (N))) = Standard_Standard
or else not
Is_RTU (Cunit_Entity (Get_Source_Unit (Etype (Prefix (N)))),
Ada_Tags)
then
Warn_On_Suspicious_Index (Name, First (Expressions (N)));
Eval_Indexed_Component (N);
end if;
-- If the array type is atomic and the component is not, then this is
-- worth a warning before Ada 2020, since we have a situation where the
-- access to the component may cause extra read/writes of the atomic
-- object, or partial word accesses, both of which may be unexpected.
if Nkind (N) = N_Indexed_Component
and then Is_Atomic_Ref_With_Address (N)
and then not (Has_Atomic_Components (Array_Type)
or else (Is_Entity_Name (Prefix (N))
and then Has_Atomic_Components
(Entity (Prefix (N)))))
and then not Is_Atomic (Component_Type (Array_Type))
and then Ada_Version < Ada_2020
then
Error_Msg_N
("??access to non-atomic component of atomic array", Prefix (N));
Error_Msg_N
("??\may cause unexpected accesses to atomic object", Prefix (N));
end if;
end Resolve_Indexed_Component;
-----------------------------
-- Resolve_Integer_Literal --
-----------------------------
procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id) is
begin
Set_Etype (N, Typ);
Eval_Integer_Literal (N);
end Resolve_Integer_Literal;
--------------------------------
-- Resolve_Intrinsic_Operator --
--------------------------------
procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id) is
Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
Op : Entity_Id;
Arg1 : Node_Id;
Arg2 : Node_Id;
function Convert_Operand (Opnd : Node_Id) return Node_Id;
-- If the operand is a literal, it cannot be the expression in a
-- conversion. Use a qualified expression instead.
---------------------
-- Convert_Operand --
---------------------
function Convert_Operand (Opnd : Node_Id) return Node_Id is
Loc : constant Source_Ptr := Sloc (Opnd);
Res : Node_Id;
begin
if Nkind (Opnd) in N_Integer_Literal | N_Real_Literal then
Res :=
Make_Qualified_Expression (Loc,
Subtype_Mark => New_Occurrence_Of (Btyp, Loc),
Expression => Relocate_Node (Opnd));
Analyze (Res);
else
Res := Unchecked_Convert_To (Btyp, Opnd);
end if;
return Res;
end Convert_Operand;
-- Start of processing for Resolve_Intrinsic_Operator
begin
-- We must preserve the original entity in a generic setting, so that
-- the legality of the operation can be verified in an instance.
if not Expander_Active then
return;
end if;
Op := Entity (N);
while Scope (Op) /= Standard_Standard loop
Op := Homonym (Op);
pragma Assert (Present (Op));
end loop;
Set_Entity (N, Op);
Set_Is_Overloaded (N, False);
-- If the result or operand types are private, rewrite with unchecked
-- conversions on the operands and the result, to expose the proper
-- underlying numeric type.
if Is_Private_Type (Typ)
or else Is_Private_Type (Etype (Left_Opnd (N)))
or else Is_Private_Type (Etype (Right_Opnd (N)))
then
Arg1 := Convert_Operand (Left_Opnd (N));
if Nkind (N) = N_Op_Expon then
Arg2 := Unchecked_Convert_To (Standard_Integer, Right_Opnd (N));
else
Arg2 := Convert_Operand (Right_Opnd (N));
end if;
if Nkind (Arg1) = N_Type_Conversion then
Save_Interps (Left_Opnd (N), Expression (Arg1));
end if;
if Nkind (Arg2) = N_Type_Conversion then
Save_Interps (Right_Opnd (N), Expression (Arg2));
end if;
Set_Left_Opnd (N, Arg1);
Set_Right_Opnd (N, Arg2);
Set_Etype (N, Btyp);
Rewrite (N, Unchecked_Convert_To (Typ, N));
Resolve (N, Typ);
elsif Typ /= Etype (Left_Opnd (N))
or else Typ /= Etype (Right_Opnd (N))
then
-- Add explicit conversion where needed, and save interpretations in
-- case operands are overloaded.
Arg1 := Convert_To (Typ, Left_Opnd (N));
Arg2 := Convert_To (Typ, Right_Opnd (N));
if Nkind (Arg1) = N_Type_Conversion then
Save_Interps (Left_Opnd (N), Expression (Arg1));
else
Save_Interps (Left_Opnd (N), Arg1);
end if;
if Nkind (Arg2) = N_Type_Conversion then
Save_Interps (Right_Opnd (N), Expression (Arg2));
else
Save_Interps (Right_Opnd (N), Arg2);
end if;
Rewrite (Left_Opnd (N), Arg1);
Rewrite (Right_Opnd (N), Arg2);
Analyze (Arg1);
Analyze (Arg2);
Resolve_Arithmetic_Op (N, Typ);
else
Resolve_Arithmetic_Op (N, Typ);
end if;
end Resolve_Intrinsic_Operator;
--------------------------------------
-- Resolve_Intrinsic_Unary_Operator --
--------------------------------------
procedure Resolve_Intrinsic_Unary_Operator
(N : Node_Id;
Typ : Entity_Id)
is
Btyp : constant Entity_Id := Base_Type (Underlying_Type (Typ));
Op : Entity_Id;
Arg2 : Node_Id;
begin
Op := Entity (N);
while Scope (Op) /= Standard_Standard loop
Op := Homonym (Op);
pragma Assert (Present (Op));
end loop;
Set_Entity (N, Op);
if Is_Private_Type (Typ) then
Arg2 := Unchecked_Convert_To (Btyp, Right_Opnd (N));
Save_Interps (Right_Opnd (N), Expression (Arg2));
Set_Right_Opnd (N, Arg2);
Set_Etype (N, Btyp);
Rewrite (N, Unchecked_Convert_To (Typ, N));
Resolve (N, Typ);
else
Resolve_Unary_Op (N, Typ);
end if;
end Resolve_Intrinsic_Unary_Operator;
------------------------
-- Resolve_Logical_Op --
------------------------
procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id) is
B_Typ : Entity_Id;
begin
Check_No_Direct_Boolean_Operators (N);
-- Predefined operations on scalar types yield the base type. On the
-- other hand, logical operations on arrays yield the type of the
-- arguments (and the context).
if Is_Array_Type (Typ) then
B_Typ := Typ;
else
B_Typ := Base_Type (Typ);
end if;
-- The following test is required because the operands of the operation
-- may be literals, in which case the resulting type appears to be
-- compatible with a signed integer type, when in fact it is compatible
-- only with modular types. If the context itself is universal, the
-- operation is illegal.
if not Valid_Boolean_Arg (Typ) then
Error_Msg_N ("invalid context for logical operation", N);
Set_Etype (N, Any_Type);
return;
elsif Typ = Any_Modular then
Error_Msg_N
("no modular type available in this context", N);
Set_Etype (N, Any_Type);
return;
elsif Is_Modular_Integer_Type (Typ)
and then Etype (Left_Opnd (N)) = Universal_Integer
and then Etype (Right_Opnd (N)) = Universal_Integer
then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
-- is active and the result type is standard Boolean (do not mess with
-- ops that return a nonstandard Boolean type, because something strange
-- is going on).
-- Note: you might expect this replacement to be done during expansion,
-- but that doesn't work, because when the pragma Short_Circuit_And_Or
-- is used, no part of the right operand of an "and" or "or" operator
-- should be executed if the left operand would short-circuit the
-- evaluation of the corresponding "and then" or "or else". If we left
-- the replacement to expansion time, then run-time checks associated
-- with such operands would be evaluated unconditionally, due to being
-- before the condition prior to the rewriting as short-circuit forms
-- during expansion.
if Short_Circuit_And_Or
and then B_Typ = Standard_Boolean
and then Nkind (N) in N_Op_And | N_Op_Or
then
-- Mark the corresponding putative SCO operator as truly a logical
-- (and short-circuit) operator.
if Generate_SCO and then Comes_From_Source (N) then
Set_SCO_Logical_Operator (N);
end if;
if Nkind (N) = N_Op_And then
Rewrite (N,
Make_And_Then (Sloc (N),
Left_Opnd => Relocate_Node (Left_Opnd (N)),
Right_Opnd => Relocate_Node (Right_Opnd (N))));
Analyze_And_Resolve (N, B_Typ);
-- Case of OR changed to OR ELSE
else
Rewrite (N,
Make_Or_Else (Sloc (N),
Left_Opnd => Relocate_Node (Left_Opnd (N)),
Right_Opnd => Relocate_Node (Right_Opnd (N))));
Analyze_And_Resolve (N, B_Typ);
end if;
-- Return now, since analysis of the rewritten ops will take care of
-- other reference bookkeeping and expression folding.
return;
end if;
Resolve (Left_Opnd (N), B_Typ);
Resolve (Right_Opnd (N), B_Typ);
Check_Unset_Reference (Left_Opnd (N));
Check_Unset_Reference (Right_Opnd (N));
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N, B_Typ);
Eval_Logical_Op (N);
end Resolve_Logical_Op;
---------------------------
-- Resolve_Membership_Op --
---------------------------
-- The context can only be a boolean type, and does not determine the
-- arguments. Arguments should be unambiguous, but the preference rule for
-- universal types applies.
procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id) is
pragma Assert (Is_Boolean_Type (Typ));
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id;
procedure Resolve_Set_Membership;
-- Analysis has determined a unique type for the left operand. Use it as
-- the basis to resolve the disjuncts.
----------------------------
-- Resolve_Set_Membership --
----------------------------
procedure Resolve_Set_Membership is
Alt : Node_Id;
begin
-- If the left operand is overloaded, find type compatible with not
-- overloaded alternative of the right operand.
Alt := First (Alternatives (N));
if Is_Overloaded (L) then
T := Empty;
while Present (Alt) loop
if not Is_Overloaded (Alt) then
T := Intersect_Types (L, Alt);
exit;
else
Next (Alt);
end if;
end loop;
-- Unclear how to resolve expression if all alternatives are also
-- overloaded.
if No (T) then
Error_Msg_N ("ambiguous expression", N);
end if;
else
T := Intersect_Types (L, Alt);
end if;
Resolve (L, T);
Alt := First (Alternatives (N));
while Present (Alt) loop
-- Alternative is an expression, a range
-- or a subtype mark.
if not Is_Entity_Name (Alt)
or else not Is_Type (Entity (Alt))
then
Resolve (Alt, T);
end if;
Next (Alt);
end loop;
-- Check for duplicates for discrete case
if Is_Discrete_Type (T) then
declare
type Ent is record
Alt : Node_Id;
Val : Uint;
end record;
Alts : array (0 .. List_Length (Alternatives (N))) of Ent;
Nalts : Nat;
begin
-- Loop checking duplicates. This is quadratic, but giant sets
-- are unlikely in this context so it's a reasonable choice.
Nalts := 0;
Alt := First (Alternatives (N));
while Present (Alt) loop
if Is_OK_Static_Expression (Alt)
and then Nkind (Alt) in N_Integer_Literal
| N_Character_Literal
| N_Has_Entity
then
Nalts := Nalts + 1;
Alts (Nalts) := (Alt, Expr_Value (Alt));
for J in 1 .. Nalts - 1 loop
if Alts (J).Val = Alts (Nalts).Val then
Error_Msg_Sloc := Sloc (Alts (J).Alt);
Error_Msg_N ("duplicate of value given#??", Alt);
end if;
end loop;
end if;
Next (Alt);
end loop;
end;
end if;
-- RM 4.5.2 (28.1/3) specifies that for types other than records or
-- limited types, evaluation of a membership test uses the predefined
-- equality for the type. This may be confusing to users, and the
-- following warning appears useful for the most common case.
if Is_Scalar_Type (Etype (L))
and then Present (Get_User_Defined_Eq (Etype (L)))
then
Error_Msg_NE
("membership test on& uses predefined equality?", N, Etype (L));
Error_Msg_N
("\even if user-defined equality exists (RM 4.5.2 (28.1/3)?", N);
end if;
end Resolve_Set_Membership;
-- Start of processing for Resolve_Membership_Op
begin
if L = Error or else R = Error then
return;
end if;
if Present (Alternatives (N)) then
Resolve_Set_Membership;
goto SM_Exit;
elsif not Is_Overloaded (R)
and then
(Etype (R) = Universal_Integer
or else
Etype (R) = Universal_Real)
and then Is_Overloaded (L)
then
T := Etype (R);
-- Ada 2005 (AI-251): Support the following case:
-- type I is interface;
-- type T is tagged ...
-- function Test (O : I'Class) is
-- begin
-- return O in T'Class.
-- end Test;
-- In this case we have nothing else to do. The membership test will be
-- done at run time.
elsif Ada_Version >= Ada_2005
and then Is_Class_Wide_Type (Etype (L))
and then Is_Interface (Etype (L))
and then not Is_Interface (Etype (R))
then
return;
else
T := Intersect_Types (L, R);
end if;
-- If mixed-mode operations are present and operands are all literal,
-- the only interpretation involves Duration, which is probably not
-- the intention of the programmer.
if T = Any_Fixed then
T := Unique_Fixed_Point_Type (N);
if T = Any_Type then
return;
end if;
end if;
Resolve (L, T);
Check_Unset_Reference (L);
if Nkind (R) = N_Range
and then not Is_Scalar_Type (T)
then
Error_Msg_N ("scalar type required for range", R);
end if;
if Is_Entity_Name (R) then
Freeze_Expression (R);
else
Resolve (R, T);
Check_Unset_Reference (R);
end if;
-- Here after resolving membership operation
<<SM_Exit>>
Eval_Membership_Op (N);
end Resolve_Membership_Op;
------------------
-- Resolve_Null --
------------------
procedure Resolve_Null (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
begin
-- Handle restriction against anonymous null access values This
-- restriction can be turned off using -gnatdj.
-- Ada 2005 (AI-231): Remove restriction
if Ada_Version < Ada_2005
and then not Debug_Flag_J
and then Ekind (Typ) = E_Anonymous_Access_Type
and then Comes_From_Source (N)
then
-- In the common case of a call which uses an explicitly null value
-- for an access parameter, give specialized error message.
if Nkind (Parent (N)) in N_Subprogram_Call then
Error_Msg_N
("NULL is not allowed as argument for an access parameter", N);
-- Standard message for all other cases (are there any?)
else
Error_Msg_N
("NULL cannot be of an anonymous access type", N);
end if;
end if;
-- Ada 2005 (AI-231): Generate the null-excluding check in case of
-- assignment to a null-excluding object.
if Ada_Version >= Ada_2005
and then Can_Never_Be_Null (Typ)
and then Nkind (Parent (N)) = N_Assignment_Statement
then
if Inside_Init_Proc then
-- Decide whether to generate an if_statement around our
-- null-excluding check to avoid them on certain internal object
-- declarations by looking at the type the current Init_Proc
-- belongs to.
-- Generate:
-- if T1b_skip_null_excluding_check then
-- [constraint_error "access check failed"]
-- end if;
if Needs_Conditional_Null_Excluding_Check
(Etype (First_Formal (Enclosing_Init_Proc)))
then
Insert_Action (N,
Make_If_Statement (Loc,
Condition =>
Make_Identifier (Loc,
New_External_Name
(Chars (Typ), "_skip_null_excluding_check")),
Then_Statements =>
New_List (
Make_Raise_Constraint_Error (Loc,
Reason => CE_Access_Check_Failed))));
-- Otherwise, simply create the check
else
Insert_Action (N,
Make_Raise_Constraint_Error (Loc,
Reason => CE_Access_Check_Failed));
end if;
else
Insert_Action
(Compile_Time_Constraint_Error (N,
"(Ada 2005) NULL not allowed in null-excluding objects??"),
Make_Raise_Constraint_Error (Loc,
Reason => CE_Access_Check_Failed));
end if;
end if;
-- In a distributed context, null for a remote access to subprogram may
-- need to be replaced with a special record aggregate. In this case,
-- return after having done the transformation.
if (Ekind (Typ) = E_Record_Type
or else Is_Remote_Access_To_Subprogram_Type (Typ))
and then Remote_AST_Null_Value (N, Typ)
then
return;
end if;
-- The null literal takes its type from the context
Set_Etype (N, Typ);
end Resolve_Null;
-----------------------
-- Resolve_Op_Concat --
-----------------------
procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id) is
-- We wish to avoid deep recursion, because concatenations are often
-- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
-- operands nonrecursively until we find something that is not a simple
-- concatenation (A in this case). We resolve that, and then walk back
-- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
-- to do the rest of the work at each level. The Parent pointers allow
-- us to avoid recursion, and thus avoid running out of memory. See also
-- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
NN : Node_Id := N;
Op1 : Node_Id;
begin
-- The following code is equivalent to:
-- Resolve_Op_Concat_First (NN, Typ);
-- Resolve_Op_Concat_Arg (N, ...);
-- Resolve_Op_Concat_Rest (N, Typ);
-- where the Resolve_Op_Concat_Arg call recurses back here if the left
-- operand is a concatenation.
-- Walk down left operands
loop
Resolve_Op_Concat_First (NN, Typ);
Op1 := Left_Opnd (NN);
exit when not (Nkind (Op1) = N_Op_Concat
and then not Is_Array_Type (Component_Type (Typ))
and then Entity (Op1) = Entity (NN));
NN := Op1;
end loop;
-- Now (given the above example) NN is A&B and Op1 is A
-- First resolve Op1 ...
Resolve_Op_Concat_Arg (NN, Op1, Typ, Is_Component_Left_Opnd (NN));
-- ... then walk NN back up until we reach N (where we started), calling
-- Resolve_Op_Concat_Rest along the way.
loop
Resolve_Op_Concat_Rest (NN, Typ);
exit when NN = N;
NN := Parent (NN);
end loop;
end Resolve_Op_Concat;
---------------------------
-- Resolve_Op_Concat_Arg --
---------------------------
procedure Resolve_Op_Concat_Arg
(N : Node_Id;
Arg : Node_Id;
Typ : Entity_Id;
Is_Comp : Boolean)
is
Btyp : constant Entity_Id := Base_Type (Typ);
Ctyp : constant Entity_Id := Component_Type (Typ);
begin
if In_Instance then
if Is_Comp
or else (not Is_Overloaded (Arg)
and then Etype (Arg) /= Any_Composite
and then Covers (Ctyp, Etype (Arg)))
then
Resolve (Arg, Ctyp);
else
Resolve (Arg, Btyp);
end if;
-- If both Array & Array and Array & Component are visible, there is a
-- potential ambiguity that must be reported.
elsif Has_Compatible_Type (Arg, Ctyp) then
if Nkind (Arg) = N_Aggregate
and then Is_Composite_Type (Ctyp)
then
if Is_Private_Type (Ctyp) then
Resolve (Arg, Btyp);
-- If the operation is user-defined and not overloaded use its
-- profile. The operation may be a renaming, in which case it has
-- been rewritten, and we want the original profile.
elsif not Is_Overloaded (N)
and then Comes_From_Source (Entity (Original_Node (N)))
and then Ekind (Entity (Original_Node (N))) = E_Function
then
Resolve (Arg,
Etype
(Next_Formal (First_Formal (Entity (Original_Node (N))))));
return;
-- Otherwise an aggregate may match both the array type and the
-- component type.
else
Error_Msg_N ("ambiguous aggregate must be qualified", Arg);
Set_Etype (Arg, Any_Type);
end if;
else
if Is_Overloaded (Arg)
and then Has_Compatible_Type (Arg, Typ)
and then Etype (Arg) /= Any_Type
then
declare
I : Interp_Index;
It : Interp;
Func : Entity_Id;
begin
Get_First_Interp (Arg, I, It);
Func := It.Nam;
Get_Next_Interp (I, It);
-- Special-case the error message when the overloading is
-- caused by a function that yields an array and can be
-- called without parameters.
if It.Nam = Func then
Error_Msg_Sloc := Sloc (Func);
Error_Msg_N ("ambiguous call to function#", Arg);
Error_Msg_NE
("\\interpretation as call yields&", Arg, Typ);
Error_Msg_NE
("\\interpretation as indexing of call yields&",
Arg, Component_Type (Typ));
else
Error_Msg_N ("ambiguous operand for concatenation!", Arg);
Get_First_Interp (Arg, I, It);
while Present (It.Nam) loop
Error_Msg_Sloc := Sloc (It.Nam);
if Base_Type (It.Typ) = Btyp
or else
Base_Type (It.Typ) = Base_Type (Ctyp)
then
Error_Msg_N -- CODEFIX
("\\possible interpretation#", Arg);
end if;
Get_Next_Interp (I, It);
end loop;
end if;
end;
end if;
Resolve (Arg, Component_Type (Typ));
if Nkind (Arg) = N_String_Literal then
Set_Etype (Arg, Component_Type (Typ));
end if;
if Arg = Left_Opnd (N) then
Set_Is_Component_Left_Opnd (N);
else
Set_Is_Component_Right_Opnd (N);
end if;
end if;
else
Resolve (Arg, Btyp);
end if;
Check_Unset_Reference (Arg);
end Resolve_Op_Concat_Arg;
-----------------------------
-- Resolve_Op_Concat_First --
-----------------------------
procedure Resolve_Op_Concat_First (N : Node_Id; Typ : Entity_Id) is
Btyp : constant Entity_Id := Base_Type (Typ);
Op1 : constant Node_Id := Left_Opnd (N);
Op2 : constant Node_Id := Right_Opnd (N);
begin
-- The parser folds an enormous sequence of concatenations of string
-- literals into "" & "...", where the Is_Folded_In_Parser flag is set
-- in the right operand. If the expression resolves to a predefined "&"
-- operator, all is well. Otherwise, the parser's folding is wrong, so
-- we give an error. See P_Simple_Expression in Par.Ch4.
if Nkind (Op2) = N_String_Literal
and then Is_Folded_In_Parser (Op2)
and then Ekind (Entity (N)) = E_Function
then
pragma Assert (Nkind (Op1) = N_String_Literal -- should be ""
and then String_Length (Strval (Op1)) = 0);
Error_Msg_N ("too many user-defined concatenations", N);
return;
end if;
Set_Etype (N, Btyp);
if Is_Limited_Composite (Btyp) then
Error_Msg_N ("concatenation not available for limited array", N);
Explain_Limited_Type (Btyp, N);
end if;
end Resolve_Op_Concat_First;
----------------------------
-- Resolve_Op_Concat_Rest --
----------------------------
procedure Resolve_Op_Concat_Rest (N : Node_Id; Typ : Entity_Id) is
Op1 : constant Node_Id := Left_Opnd (N);
Op2 : constant Node_Id := Right_Opnd (N);
begin
Resolve_Op_Concat_Arg (N, Op2, Typ, Is_Component_Right_Opnd (N));
Generate_Operator_Reference (N, Typ);
if Is_String_Type (Typ) then
Eval_Concatenation (N);
end if;
-- If this is not a static concatenation, but the result is a string
-- type (and not an array of strings) ensure that static string operands
-- have their subtypes properly constructed.
if Nkind (N) /= N_String_Literal
and then Is_Character_Type (Component_Type (Typ))
then
Set_String_Literal_Subtype (Op1, Typ);
Set_String_Literal_Subtype (Op2, Typ);
end if;
end Resolve_Op_Concat_Rest;
----------------------
-- Resolve_Op_Expon --
----------------------
procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
begin
-- Catch attempts to do fixed-point exponentiation with universal
-- operands, which is a case where the illegality is not caught during
-- normal operator analysis. This is not done in preanalysis mode
-- since the tree is not fully decorated during preanalysis.
if Full_Analysis then
if Is_Fixed_Point_Type (Typ) and then Comes_From_Source (N) then
Error_Msg_N ("exponentiation not available for fixed point", N);
return;
elsif Nkind (Parent (N)) in N_Op
and then Present (Etype (Parent (N)))
and then Is_Fixed_Point_Type (Etype (Parent (N)))
and then Etype (N) = Universal_Real
and then Comes_From_Source (N)
then
Error_Msg_N ("exponentiation not available for fixed point", N);
return;
end if;
end if;
if Comes_From_Source (N)
and then Ekind (Entity (N)) = E_Function
and then Is_Imported (Entity (N))
and then Is_Intrinsic_Subprogram (Entity (N))
then
Resolve_Intrinsic_Operator (N, Typ);
return;
end if;
if Etype (Left_Opnd (N)) = Universal_Integer
or else Etype (Left_Opnd (N)) = Universal_Real
then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- We do the resolution using the base type, because intermediate values
-- in expressions are always of the base type, not a subtype of it.
Resolve (Left_Opnd (N), B_Typ);
Resolve (Right_Opnd (N), Standard_Integer);
-- For integer types, right argument must be in Natural range
if Is_Integer_Type (Typ) then
Apply_Scalar_Range_Check (Right_Opnd (N), Standard_Natural);
end if;
Check_Unset_Reference (Left_Opnd (N));
Check_Unset_Reference (Right_Opnd (N));
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N, B_Typ);
Analyze_Dimension (N);
if Ada_Version >= Ada_2012 and then Has_Dimension_System (B_Typ) then
-- Evaluate the exponentiation operator for dimensioned type
Eval_Op_Expon_For_Dimensioned_Type (N, B_Typ);
else
Eval_Op_Expon (N);
end if;
-- Set overflow checking bit. Much cleverer code needed here eventually
-- and perhaps the Resolve routines should be separated for the various
-- arithmetic operations, since they will need different processing. ???
if Nkind (N) in N_Op then
if not Overflow_Checks_Suppressed (Etype (N)) then
Enable_Overflow_Check (N);
end if;
end if;
end Resolve_Op_Expon;
--------------------
-- Resolve_Op_Not --
--------------------
procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id) is
function Parent_Is_Boolean return Boolean;
-- This function determines if the parent node is a boolean operator or
-- operation (comparison op, membership test, or short circuit form) and
-- the not in question is the left operand of this operation. Note that
-- if the not is in parens, then false is returned.
-----------------------
-- Parent_Is_Boolean --
-----------------------
function Parent_Is_Boolean return Boolean is
begin
return Paren_Count (N) = 0
and then Nkind (Parent (N)) in N_Membership_Test
| N_Op_Boolean
| N_Short_Circuit
and then Left_Opnd (Parent (N)) = N;
end Parent_Is_Boolean;
-- Local variables
B_Typ : Entity_Id;
-- Start of processing for Resolve_Op_Not
begin
-- Predefined operations on scalar types yield the base type. On the
-- other hand, logical operations on arrays yield the type of the
-- arguments (and the context).
if Is_Array_Type (Typ) then
B_Typ := Typ;
else
B_Typ := Base_Type (Typ);
end if;
-- Straightforward case of incorrect arguments
if not Valid_Boolean_Arg (Typ) then
Error_Msg_N ("invalid operand type for operator&", N);
Set_Etype (N, Any_Type);
return;
-- Special case of probable missing parens
elsif Typ = Universal_Integer or else Typ = Any_Modular then
if Parent_Is_Boolean then
Error_Msg_N
("operand of NOT must be enclosed in parentheses",
Right_Opnd (N));
else
Error_Msg_N
("no modular type available in this context", N);
end if;
Set_Etype (N, Any_Type);
return;
-- OK resolution of NOT
else
-- Warn if non-boolean types involved. This is a case like not a < b
-- where a and b are modular, where we will get (not a) < b and most
-- likely not (a < b) was intended.
if Warn_On_Questionable_Missing_Parens
and then not Is_Boolean_Type (Typ)
and then Parent_Is_Boolean
then
Error_Msg_N ("?q?not expression should be parenthesized here!", N);
end if;
-- Warn on double negation if checking redundant constructs
if Warn_On_Redundant_Constructs
and then Comes_From_Source (N)
and then Comes_From_Source (Right_Opnd (N))
and then Root_Type (Typ) = Standard_Boolean
and then Nkind (Right_Opnd (N)) = N_Op_Not
then
Error_Msg_N ("redundant double negation?r?", N);
end if;
-- Complete resolution and evaluation of NOT
-- If argument is an equality and expected type is boolean, that
-- expected type has no effect on resolution, and there are
-- special rules for resolution of Eq, Neq in the presence of
-- overloaded operands, so we directly call its resolution routines.
declare
Opnd : constant Node_Id := Right_Opnd (N);
Op_Id : Entity_Id;
begin
if B_Typ = Standard_Boolean
and then Nkind (Opnd) in N_Op_Eq | N_Op_Ne
and then Is_Overloaded (Opnd)
then
Resolve_Equality_Op (Opnd, B_Typ);
Op_Id := Entity (Opnd);
if Ekind (Op_Id) = E_Function
and then not Is_Intrinsic_Subprogram (Op_Id)
then
Rewrite_Operator_As_Call (Opnd, Op_Id);
end if;
if not Inside_A_Generic or else Is_Entity_Name (Opnd) then
Freeze_Expression (Opnd);
end if;
Expand (Opnd);
else
Resolve (Opnd, B_Typ);
end if;
Check_Unset_Reference (Opnd);
end;
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N, B_Typ);
Eval_Op_Not (N);
end if;
end Resolve_Op_Not;
-----------------------------
-- Resolve_Operator_Symbol --
-----------------------------
-- Nothing to be done, all resolved already
procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id) is
pragma Warnings (Off, N);
pragma Warnings (Off, Typ);
begin
null;
end Resolve_Operator_Symbol;
----------------------------------
-- Resolve_Qualified_Expression --
----------------------------------
procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id) is
pragma Warnings (Off, Typ);
Target_Typ : constant Entity_Id := Entity (Subtype_Mark (N));
Expr : constant Node_Id := Expression (N);
begin
Resolve (Expr, Target_Typ);
-- A qualified expression requires an exact match of the type, class-
-- wide matching is not allowed. However, if the qualifying type is
-- specific and the expression has a class-wide type, it may still be
-- okay, since it can be the result of the expansion of a call to a
-- dispatching function, so we also have to check class-wideness of the
-- type of the expression's original node.
if (Is_Class_Wide_Type (Target_Typ)
or else
(Is_Class_Wide_Type (Etype (Expr))
and then Is_Class_Wide_Type (Etype (Original_Node (Expr)))))
and then Base_Type (Etype (Expr)) /= Base_Type (Target_Typ)
then
Wrong_Type (Expr, Target_Typ);
end if;
-- If the target type is unconstrained, then we reset the type of the
-- result from the type of the expression. For other cases, the actual
-- subtype of the expression is the target type. But we avoid doing it
-- for an allocator since this is not needed and might be problematic.
if Is_Composite_Type (Target_Typ)
and then not Is_Constrained (Target_Typ)
and then Nkind (Parent (N)) /= N_Allocator
then
Set_Etype (N, Etype (Expr));
end if;
Analyze_Dimension (N);
Eval_Qualified_Expression (N);
-- If we still have a qualified expression after the static evaluation,
-- then apply a scalar range check if needed. The reason that we do this
-- after the Eval call is that otherwise, the application of the range
-- check may convert an illegal static expression and result in warning
-- rather than giving an error (e.g Integer'(Integer'Last + 1)).
if Nkind (N) = N_Qualified_Expression
and then Is_Scalar_Type (Target_Typ)
then
Apply_Scalar_Range_Check (Expr, Target_Typ);
end if;
-- AI12-0100: Once the qualified expression is resolved, check whether
-- operand statisfies a static predicate of the target subtype, if any.
-- In the static expression case, a predicate check failure is an error.
if Has_Predicates (Target_Typ) then
Check_Expression_Against_Static_Predicate
(Expr, Target_Typ, Static_Failure_Is_Error => True);
end if;
end Resolve_Qualified_Expression;
------------------------------
-- Resolve_Raise_Expression --
------------------------------
procedure Resolve_Raise_Expression (N : Node_Id; Typ : Entity_Id) is
begin
if Typ = Raise_Type then
Error_Msg_N ("cannot find unique type for raise expression", N);
Set_Etype (N, Any_Type);
else
Set_Etype (N, Typ);
end if;
end Resolve_Raise_Expression;
-------------------
-- Resolve_Range --
-------------------
procedure Resolve_Range (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Low_Bound (N);
H : constant Node_Id := High_Bound (N);
function First_Last_Ref return Boolean;
-- Returns True if N is of the form X'First .. X'Last where X is the
-- same entity for both attributes.
--------------------
-- First_Last_Ref --
--------------------
function First_Last_Ref return Boolean is
Lorig : constant Node_Id := Original_Node (L);
Horig : constant Node_Id := Original_Node (H);
begin
if Nkind (Lorig) = N_Attribute_Reference
and then Nkind (Horig) = N_Attribute_Reference
and then Attribute_Name (Lorig) = Name_First
and then Attribute_Name (Horig) = Name_Last
then
declare
PL : constant Node_Id := Prefix (Lorig);
PH : constant Node_Id := Prefix (Horig);
begin
if Is_Entity_Name (PL)
and then Is_Entity_Name (PH)
and then Entity (PL) = Entity (PH)
then
return True;
end if;
end;
end if;
return False;
end First_Last_Ref;
-- Start of processing for Resolve_Range
begin
Set_Etype (N, Typ);
Resolve (L, Typ);
Resolve (H, Typ);
-- Reanalyze the lower bound after both bounds have been analyzed, so
-- that the range is known to be static or not by now. This may trigger
-- more compile-time evaluation, which is useful for static analysis
-- with GNATprove. This is not needed for compilation or static analysis
-- with CodePeer, as full expansion does that evaluation then.
if GNATprove_Mode then
Set_Analyzed (L, False);
Resolve (L, Typ);
end if;
-- Check for inappropriate range on unordered enumeration type
if Bad_Unordered_Enumeration_Reference (N, Typ)
-- Exclude X'First .. X'Last if X is the same entity for both
and then not First_Last_Ref
then
Error_Msg_Sloc := Sloc (Typ);
Error_Msg_NE
("subrange of unordered enumeration type& declared#?U?", N, Typ);
end if;
Check_Unset_Reference (L);
Check_Unset_Reference (H);
-- We have to check the bounds for being within the base range as
-- required for a non-static context. Normally this is automatic and
-- done as part of evaluating expressions, but the N_Range node is an
-- exception, since in GNAT we consider this node to be a subexpression,
-- even though in Ada it is not. The circuit in Sem_Eval could check for
-- this, but that would put the test on the main evaluation path for
-- expressions.
Check_Non_Static_Context (L);
Check_Non_Static_Context (H);
-- Check for an ambiguous range over character literals. This will
-- happen with a membership test involving only literals.
if Typ = Any_Character then
Ambiguous_Character (L);
Set_Etype (N, Any_Type);
return;
end if;
-- If bounds are static, constant-fold them, so size computations are
-- identical between front-end and back-end. Do not perform this
-- transformation while analyzing generic units, as type information
-- would be lost when reanalyzing the constant node in the instance.
if Is_Discrete_Type (Typ) and then Expander_Active then
if Is_OK_Static_Expression (L) then
Fold_Uint (L, Expr_Value (L), Is_OK_Static_Expression (L));
end if;
if Is_OK_Static_Expression (H) then
Fold_Uint (H, Expr_Value (H), Is_OK_Static_Expression (H));
end if;
end if;
end Resolve_Range;
--------------------------
-- Resolve_Real_Literal --
--------------------------
procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id) is
Actual_Typ : constant Entity_Id := Etype (N);
begin
-- Special processing for fixed-point literals to make sure that the
-- value is an exact multiple of small where this is required. We skip
-- this for the universal real case, and also for generic types.
if Is_Fixed_Point_Type (Typ)
and then Typ /= Universal_Fixed
and then Typ /= Any_Fixed
and then not Is_Generic_Type (Typ)
then
declare
Val : constant Ureal := Realval (N);
Cintr : constant Ureal := Val / Small_Value (Typ);
Cint : constant Uint := UR_Trunc (Cintr);
Den : constant Uint := Norm_Den (Cintr);
Stat : Boolean;
begin
-- Case of literal is not an exact multiple of the Small
if Den /= 1 then
-- For a source program literal for a decimal fixed-point type,
-- this is statically illegal (RM 4.9(36)).
if Is_Decimal_Fixed_Point_Type (Typ)
and then Actual_Typ = Universal_Real
and then Comes_From_Source (N)
then
Error_Msg_N ("value has extraneous low order digits", N);
end if;
-- Generate a warning if literal from source
if Is_OK_Static_Expression (N)
and then Warn_On_Bad_Fixed_Value
then
Error_Msg_N
("?b?static fixed-point value is not a multiple of Small!",
N);
end if;
-- Replace literal by a value that is the exact representation
-- of a value of the type, i.e. a multiple of the small value,
-- by truncation, since Machine_Rounds is false for all GNAT
-- fixed-point types (RM 4.9(38)).
Stat := Is_OK_Static_Expression (N);
Rewrite (N,
Make_Real_Literal (Sloc (N),
Realval => Small_Value (Typ) * Cint));
Set_Is_Static_Expression (N, Stat);
end if;
-- In all cases, set the corresponding integer field
Set_Corresponding_Integer_Value (N, Cint);
end;
end if;
-- Now replace the actual type by the expected type as usual
Set_Etype (N, Typ);
Eval_Real_Literal (N);
end Resolve_Real_Literal;
-----------------------
-- Resolve_Reference --
-----------------------
procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id) is
P : constant Node_Id := Prefix (N);
begin
-- Replace general access with specific type
if Ekind (Etype (N)) = E_Allocator_Type then
Set_Etype (N, Base_Type (Typ));
end if;
Resolve (P, Designated_Type (Etype (N)));
-- If we are taking the reference of a volatile entity, then treat it as
-- a potential modification of this entity. This is too conservative,
-- but necessary because remove side effects can cause transformations
-- of normal assignments into reference sequences that otherwise fail to
-- notice the modification.
if Is_Entity_Name (P) and then Treat_As_Volatile (Entity (P)) then
Note_Possible_Modification (P, Sure => False);
end if;
end Resolve_Reference;
--------------------------------
-- Resolve_Selected_Component --
--------------------------------
procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id) is
Comp : Entity_Id;
Comp1 : Entity_Id := Empty; -- prevent junk warning
P : constant Node_Id := Prefix (N);
S : constant Node_Id := Selector_Name (N);
T : Entity_Id := Etype (P);
I : Interp_Index;
I1 : Interp_Index := 0; -- prevent junk warning
It : Interp;
It1 : Interp;
Found : Boolean;
function Init_Component return Boolean;
-- Check whether this is the initialization of a component within an
-- init proc (by assignment or call to another init proc). If true,
-- there is no need for a discriminant check.
--------------------
-- Init_Component --
--------------------
function Init_Component return Boolean is
begin
return Inside_Init_Proc
and then Nkind (Prefix (N)) = N_Identifier
and then Chars (Prefix (N)) = Name_uInit
and then Nkind (Parent (Parent (N))) = N_Case_Statement_Alternative;
end Init_Component;
-- Start of processing for Resolve_Selected_Component
begin
if Is_Overloaded (P) then
-- Use the context type to select the prefix that has a selector
-- of the correct name and type.
Found := False;
Get_First_Interp (P, I, It);
Search : while Present (It.Typ) loop
if Is_Access_Type (It.Typ) then
T := Designated_Type (It.Typ);
else
T := It.Typ;
end if;
-- Locate selected component. For a private prefix the selector
-- can denote a discriminant.
if Is_Record_Type (T) or else Is_Private_Type (T) then
-- The visible components of a class-wide type are those of
-- the root type.
if Is_Class_Wide_Type (T) then
T := Etype (T);
end if;
Comp := First_Entity (T);
while Present (Comp) loop
if Chars (Comp) = Chars (S)
and then Covers (Typ, Etype (Comp))
then
if not Found then
Found := True;
I1 := I;
It1 := It;
Comp1 := Comp;
else
It := Disambiguate (P, I1, I, Any_Type);
if It = No_Interp then
Error_Msg_N
("ambiguous prefix for selected component", N);
Set_Etype (N, Typ);
return;
else
It1 := It;
-- There may be an implicit dereference. Retrieve
-- designated record type.
if Is_Access_Type (It1.Typ) then
T := Designated_Type (It1.Typ);
else
T := It1.Typ;
end if;
if Scope (Comp1) /= T then
-- Resolution chooses the new interpretation.
-- Find the component with the right name.
Comp1 := First_Entity (T);
while Present (Comp1)
and then Chars (Comp1) /= Chars (S)
loop
Next_Entity (Comp1);
end loop;
end if;
exit Search;
end if;
end if;
end if;
Next_Entity (Comp);
end loop;
end if;
Get_Next_Interp (I, It);
end loop Search;
-- There must be a legal interpretation at this point
pragma Assert (Found);
Resolve (P, It1.Typ);
-- In general the expected type is the type of the context, not the
-- type of the candidate selected component.
Set_Etype (N, Typ);
Set_Entity_With_Checks (S, Comp1);
-- The type of the context and that of the component are
-- compatible and in general identical, but if they are anonymous
-- access-to-subprogram types, the relevant type is that of the
-- component. This matters in Unnest_Subprograms mode, where the
-- relevant context is the one in which the type is declared, not
-- the point of use. This determines what activation record to use.
if Ekind (Typ) = E_Anonymous_Access_Subprogram_Type then
Set_Etype (N, Etype (Comp1));
-- When the type of the component is an access to a class-wide type
-- the relevant type is that of the component (since in such case we
-- may need to generate implicit type conversions or dispatching
-- calls).
elsif Is_Access_Type (Typ)
and then not Is_Class_Wide_Type (Designated_Type (Typ))
and then Is_Class_Wide_Type (Designated_Type (Etype (Comp1)))
then
Set_Etype (N, Etype (Comp1));
end if;
else
-- Resolve prefix with its type
Resolve (P, T);
end if;
-- Generate cross-reference. We needed to wait until full overloading
-- resolution was complete to do this, since otherwise we can't tell if
-- we are an lvalue or not.
if May_Be_Lvalue (N) then
Generate_Reference (Entity (S), S, 'm');
else
Generate_Reference (Entity (S), S, 'r');
end if;
-- If the prefix's type is an access type, get to the real record type.
-- Note: we do not apply an access check because an explicit dereference
-- will be introduced later, and the check will happen there.
if Is_Access_Type (Etype (P)) then
T := Implicitly_Designated_Type (Etype (P));
Check_Fully_Declared_Prefix (T, P);
else
T := Etype (P);
-- If the prefix is an entity it may have a deferred reference set
-- during analysis of the selected component. After resolution we
-- can transform it into a proper reference. This prevents spurious
-- warnings on useless assignments when the same selected component
-- is the actual for an out parameter in a subsequent call.
if Is_Entity_Name (P)
and then Has_Deferred_Reference (Entity (P))
then
if May_Be_Lvalue (N) then
Generate_Reference (Entity (P), P, 'm');
else
Generate_Reference (Entity (P), P, 'r');
end if;
end if;
end if;
-- Set flag for expander if discriminant check required on a component
-- appearing within a variant.
if Has_Discriminants (T)
and then Ekind (Entity (S)) = E_Component
and then Present (Original_Record_Component (Entity (S)))
and then Ekind (Original_Record_Component (Entity (S))) = E_Component
and then
Is_Declared_Within_Variant (Original_Record_Component (Entity (S)))
and then not Discriminant_Checks_Suppressed (T)
and then not Init_Component
then
Set_Do_Discriminant_Check (N);
end if;
if Ekind (Entity (S)) = E_Void then
Error_Msg_N ("premature use of component", S);
end if;
-- If the prefix is a record conversion, this may be a renamed
-- discriminant whose bounds differ from those of the original
-- one, so we must ensure that a range check is performed.
if Nkind (P) = N_Type_Conversion
and then Ekind (Entity (S)) = E_Discriminant
and then Is_Discrete_Type (Typ)
then
Set_Etype (N, Base_Type (Typ));
end if;
-- Eval_Selected_Component may e.g. fold statically known discriminants.
Eval_Selected_Component (N);
if Nkind (N) = N_Selected_Component then
-- If the record type is atomic and the component is not, then this
-- is worth a warning before Ada 2020, since we have a situation
-- where the access to the component may cause extra read/writes of
-- the atomic object, or partial word accesses, both of which may be
-- unexpected.
if Is_Atomic_Ref_With_Address (N)
and then not Is_Atomic (Entity (S))
and then not Is_Atomic (Etype (Entity (S)))
and then Ada_Version < Ada_2020
then
Error_Msg_N
("??access to non-atomic component of atomic record",
Prefix (N));
Error_Msg_N
("\??may cause unexpected accesses to atomic object",
Prefix (N));
end if;
Resolve_Implicit_Dereference (Prefix (N));
Analyze_Dimension (N);
end if;
end Resolve_Selected_Component;
-------------------
-- Resolve_Shift --
-------------------
procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
begin
-- We do the resolution using the base type, because intermediate values
-- in expressions always are of the base type, not a subtype of it.
Resolve (L, B_Typ);
Resolve (R, Standard_Natural);
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N, B_Typ);
Eval_Shift (N);
end Resolve_Shift;
---------------------------
-- Resolve_Short_Circuit --
---------------------------
procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
begin
-- Ensure all actions associated with the left operand (e.g.
-- finalization of transient objects) are fully evaluated locally within
-- an expression with actions. This is particularly helpful for coverage
-- analysis. However this should not happen in generics or if option
-- Minimize_Expression_With_Actions is set.
if Expander_Active and not Minimize_Expression_With_Actions then
declare
Reloc_L : constant Node_Id := Relocate_Node (L);
begin
Save_Interps (Old_N => L, New_N => Reloc_L);
Rewrite (L,
Make_Expression_With_Actions (Sloc (L),
Actions => New_List,
Expression => Reloc_L));
-- Set Comes_From_Source on L to preserve warnings for unset
-- reference.
Preserve_Comes_From_Source (L, Reloc_L);
end;
end if;
Resolve (L, B_Typ);
Resolve (R, B_Typ);
-- Check for issuing warning for always False assert/check, this happens
-- when assertions are turned off, in which case the pragma Assert/Check
-- was transformed into:
-- if False and then <condition> then ...
-- and we detect this pattern
if Warn_On_Assertion_Failure
and then Is_Entity_Name (R)
and then Entity (R) = Standard_False
and then Nkind (Parent (N)) = N_If_Statement
and then Nkind (N) = N_And_Then
and then Is_Entity_Name (L)
and then Entity (L) = Standard_False
then
declare
Orig : constant Node_Id := Original_Node (Parent (N));
begin
-- Special handling of Asssert pragma
if Nkind (Orig) = N_Pragma
and then Pragma_Name (Orig) = Name_Assert
then
declare
Expr : constant Node_Id :=
Original_Node
(Expression
(First (Pragma_Argument_Associations (Orig))));
begin
-- Don't warn if original condition is explicit False,
-- since obviously the failure is expected in this case.
if Is_Entity_Name (Expr)
and then Entity (Expr) = Standard_False
then
null;
-- Issue warning. We do not want the deletion of the
-- IF/AND-THEN to take this message with it. We achieve this
-- by making sure that the expanded code points to the Sloc
-- of the expression, not the original pragma.
else
-- Note: Use Error_Msg_F here rather than Error_Msg_N.
-- The source location of the expression is not usually
-- the best choice here. For example, it gets located on
-- the last AND keyword in a chain of boolean expressiond
-- AND'ed together. It is best to put the message on the
-- first character of the assertion, which is the effect
-- of the First_Node call here.
Error_Msg_F
("?A?assertion would fail at run time!",
Expression
(First (Pragma_Argument_Associations (Orig))));
end if;
end;
-- Similar processing for Check pragma
elsif Nkind (Orig) = N_Pragma
and then Pragma_Name (Orig) = Name_Check
then
-- Don't want to warn if original condition is explicit False
declare
Expr : constant Node_Id :=
Original_Node
(Expression
(Next (First (Pragma_Argument_Associations (Orig)))));
begin
if Is_Entity_Name (Expr)
and then Entity (Expr) = Standard_False
then
null;
-- Post warning
else
-- Again use Error_Msg_F rather than Error_Msg_N, see
-- comment above for an explanation of why we do this.
Error_Msg_F
("?A?check would fail at run time!",
Expression
(Last (Pragma_Argument_Associations (Orig))));
end if;
end;
end if;
end;
end if;
-- Continue with processing of short circuit
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Set_Etype (N, B_Typ);
Eval_Short_Circuit (N);
end Resolve_Short_Circuit;
-------------------
-- Resolve_Slice --
-------------------
procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id) is
Drange : constant Node_Id := Discrete_Range (N);
Name : constant Node_Id := Prefix (N);
Array_Type : Entity_Id := Empty;
Dexpr : Node_Id := Empty;
Index_Type : Entity_Id;
begin
if Is_Overloaded (Name) then
-- Use the context type to select the prefix that yields the correct
-- array type.
declare
I : Interp_Index;
I1 : Interp_Index := 0;
It : Interp;
P : constant Node_Id := Prefix (N);
Found : Boolean := False;
begin
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
if (Is_Array_Type (It.Typ)
and then Covers (Typ, It.Typ))
or else (Is_Access_Type (It.Typ)
and then Is_Array_Type (Designated_Type (It.Typ))
and then Covers (Typ, Designated_Type (It.Typ)))
then
if Found then
It := Disambiguate (P, I1, I, Any_Type);
if It = No_Interp then
Error_Msg_N ("ambiguous prefix for slicing", N);
Set_Etype (N, Typ);
return;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
end if;
Get_Next_Interp (I, It);
end loop;
end;
else
Array_Type := Etype (Name);
end if;
Resolve (Name, Array_Type);
-- If the prefix's type is an access type, get to the real array type.
-- Note: we do not apply an access check because an explicit dereference
-- will be introduced later, and the check will happen there.
if Is_Access_Type (Array_Type) then
Array_Type := Implicitly_Designated_Type (Array_Type);
-- If the prefix is an access to an unconstrained array, we must use
-- the actual subtype of the object to perform the index checks. The
-- object denoted by the prefix is implicit in the node, so we build
-- an explicit representation for it in order to compute the actual
-- subtype.
if not Is_Constrained (Array_Type) then
Remove_Side_Effects (Prefix (N));
declare
Obj : constant Node_Id :=
Make_Explicit_Dereference (Sloc (N),
Prefix => New_Copy_Tree (Prefix (N)));
begin
Set_Etype (Obj, Array_Type);
Set_Parent (Obj, Parent (N));
Array_Type := Get_Actual_Subtype (Obj);
end;
end if;
elsif Is_Entity_Name (Name)
or else Nkind (Name) = N_Explicit_Dereference
or else (Nkind (Name) = N_Function_Call
and then not Is_Constrained (Etype (Name)))
then
Array_Type := Get_Actual_Subtype (Name);
-- If the name is a selected component that depends on discriminants,
-- build an actual subtype for it. This can happen only when the name
-- itself is overloaded; otherwise the actual subtype is created when
-- the selected component is analyzed.
elsif Nkind (Name) = N_Selected_Component
and then Full_Analysis
and then Depends_On_Discriminant (First_Index (Array_Type))
then
declare
Act_Decl : constant Node_Id :=
Build_Actual_Subtype_Of_Component (Array_Type, Name);
begin
Insert_Action (N, Act_Decl);
Array_Type := Defining_Identifier (Act_Decl);
end;
-- Maybe this should just be "else", instead of checking for the
-- specific case of slice??? This is needed for the case where the
-- prefix is an Image attribute, which gets expanded to a slice, and so
-- has a constrained subtype which we want to use for the slice range
-- check applied below (the range check won't get done if the
-- unconstrained subtype of the 'Image is used).
elsif Nkind (Name) = N_Slice then
Array_Type := Etype (Name);
end if;
-- Obtain the type of the array index
if Ekind (Array_Type) = E_String_Literal_Subtype then
Index_Type := Etype (String_Literal_Low_Bound (Array_Type));
else
Index_Type := Etype (First_Index (Array_Type));
end if;
-- If name was overloaded, set slice type correctly now
Set_Etype (N, Array_Type);
-- Handle the generation of a range check that compares the array index
-- against the discrete_range. The check is not applied to internally
-- built nodes associated with the expansion of dispatch tables. Check
-- that Ada.Tags has already been loaded to avoid extra dependencies on
-- the unit.
if Tagged_Type_Expansion
and then RTU_Loaded (Ada_Tags)
and then Nkind (Prefix (N)) = N_Selected_Component
and then Present (Entity (Selector_Name (Prefix (N))))
and then Entity (Selector_Name (Prefix (N))) =
RTE_Record_Component (RE_Prims_Ptr)
then
null;
-- The discrete_range is specified by a subtype indication. Create a
-- shallow copy and inherit the type, parent and source location from
-- the discrete_range. This ensures that the range check is inserted
-- relative to the slice and that the runtime exception points to the
-- proper construct.
elsif Is_Entity_Name (Drange) then
Dexpr := New_Copy (Scalar_Range (Entity (Drange)));
Set_Etype (Dexpr, Etype (Drange));
Set_Parent (Dexpr, Parent (Drange));
Set_Sloc (Dexpr, Sloc (Drange));
-- The discrete_range is a regular range. Resolve the bounds and remove
-- their side effects.
else
Resolve (Drange, Base_Type (Index_Type));
if Nkind (Drange) = N_Range then
Force_Evaluation (Low_Bound (Drange));
Force_Evaluation (High_Bound (Drange));
Dexpr := Drange;
end if;
end if;
if Present (Dexpr) then
Apply_Range_Check (Dexpr, Index_Type);
end if;
Set_Slice_Subtype (N);
-- Check bad use of type with predicates
declare
Subt : Entity_Id;
begin
if Nkind (Drange) = N_Subtype_Indication
and then Has_Predicates (Entity (Subtype_Mark (Drange)))
then
Subt := Entity (Subtype_Mark (Drange));
else
Subt := Etype (Drange);
end if;
if Has_Predicates (Subt) then
Bad_Predicated_Subtype_Use
("subtype& has predicate, not allowed in slice", Drange, Subt);
end if;
end;
-- Otherwise here is where we check suspicious indexes
if Nkind (Drange) = N_Range then
Warn_On_Suspicious_Index (Name, Low_Bound (Drange));
Warn_On_Suspicious_Index (Name, High_Bound (Drange));
end if;
Resolve_Implicit_Dereference (Prefix (N));
Analyze_Dimension (N);
Eval_Slice (N);
end Resolve_Slice;
----------------------------
-- Resolve_String_Literal --
----------------------------
procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id) is
C_Typ : constant Entity_Id := Component_Type (Typ);
R_Typ : constant Entity_Id := Root_Type (C_Typ);
Loc : constant Source_Ptr := Sloc (N);
Str : constant String_Id := Strval (N);
Strlen : constant Nat := String_Length (Str);
Subtype_Id : Entity_Id;
Need_Check : Boolean;
begin
-- For a string appearing in a concatenation, defer creation of the
-- string_literal_subtype until the end of the resolution of the
-- concatenation, because the literal may be constant-folded away. This
-- is a useful optimization for long concatenation expressions.
-- If the string is an aggregate built for a single character (which
-- happens in a non-static context) or a is null string to which special
-- checks may apply, we build the subtype. Wide strings must also get a
-- string subtype if they come from a one character aggregate. Strings
-- generated by attributes might be static, but it is often hard to
-- determine whether the enclosing context is static, so we generate
-- subtypes for them as well, thus losing some rarer optimizations ???
-- Same for strings that come from a static conversion.
Need_Check :=
(Strlen = 0 and then Typ /= Standard_String)
or else Nkind (Parent (N)) /= N_Op_Concat
or else (N /= Left_Opnd (Parent (N))
and then N /= Right_Opnd (Parent (N)))
or else ((Typ = Standard_Wide_String
or else Typ = Standard_Wide_Wide_String)
and then Nkind (Original_Node (N)) /= N_String_Literal);
-- If the resolving type is itself a string literal subtype, we can just
-- reuse it, since there is no point in creating another.
if Ekind (Typ) = E_String_Literal_Subtype then
Subtype_Id := Typ;
elsif Nkind (Parent (N)) = N_Op_Concat
and then not Need_Check
and then Nkind (Original_Node (N)) not in N_Character_Literal
| N_Attribute_Reference
| N_Qualified_Expression
| N_Type_Conversion
then
Subtype_Id := Typ;
-- Do not generate a string literal subtype for the default expression
-- of a formal parameter in GNATprove mode. This is because the string
-- subtype is associated with the freezing actions of the subprogram,
-- however freezing is disabled in GNATprove mode and as a result the
-- subtype is unavailable.
elsif GNATprove_Mode
and then Nkind (Parent (N)) = N_Parameter_Specification
then
Subtype_Id := Typ;
-- Otherwise we must create a string literal subtype. Note that the
-- whole idea of string literal subtypes is simply to avoid the need
-- for building a full fledged array subtype for each literal.
else
Set_String_Literal_Subtype (N, Typ);
Subtype_Id := Etype (N);
end if;
if Nkind (Parent (N)) /= N_Op_Concat
or else Need_Check
then
Set_Etype (N, Subtype_Id);
Eval_String_Literal (N);
end if;
if Is_Limited_Composite (Typ)
or else Is_Private_Composite (Typ)
then
Error_Msg_N ("string literal not available for private array", N);
Set_Etype (N, Any_Type);
return;
end if;
-- The validity of a null string has been checked in the call to
-- Eval_String_Literal.
if Strlen = 0 then
return;
-- Always accept string literal with component type Any_Character, which
-- occurs in error situations and in comparisons of literals, both of
-- which should accept all literals.
elsif R_Typ = Any_Character then
return;
-- If the type is bit-packed, then we always transform the string
-- literal into a full fledged aggregate.
elsif Is_Bit_Packed_Array (Typ) then
null;
-- Deal with cases of Wide_Wide_String, Wide_String, and String
else
-- For Standard.Wide_Wide_String, or any other type whose component
-- type is Standard.Wide_Wide_Character, we know that all the
-- characters in the string must be acceptable, since the parser
-- accepted the characters as valid character literals.
if R_Typ = Standard_Wide_Wide_Character then
null;
-- For the case of Standard.String, or any other type whose component
-- type is Standard.Character, we must make sure that there are no
-- wide characters in the string, i.e. that it is entirely composed
-- of characters in range of type Character.
-- If the string literal is the result of a static concatenation, the
-- test has already been performed on the components, and need not be
-- repeated.
elsif R_Typ = Standard_Character
and then Nkind (Original_Node (N)) /= N_Op_Concat
then
for J in 1 .. Strlen loop
if not In_Character_Range (Get_String_Char (Str, J)) then
-- If we are out of range, post error. This is one of the
-- very few places that we place the flag in the middle of
-- a token, right under the offending wide character. Not
-- quite clear if this is right wrt wide character encoding
-- sequences, but it's only an error message.
Error_Msg
("literal out of range of type Standard.Character",
Source_Ptr (Int (Loc) + J));
return;
end if;
end loop;
-- For the case of Standard.Wide_String, or any other type whose
-- component type is Standard.Wide_Character, we must make sure that
-- there are no wide characters in the string, i.e. that it is
-- entirely composed of characters in range of type Wide_Character.
-- If the string literal is the result of a static concatenation,
-- the test has already been performed on the components, and need
-- not be repeated.
elsif R_Typ = Standard_Wide_Character
and then Nkind (Original_Node (N)) /= N_Op_Concat
then
for J in 1 .. Strlen loop
if not In_Wide_Character_Range (Get_String_Char (Str, J)) then
-- If we are out of range, post error. This is one of the
-- very few places that we place the flag in the middle of
-- a token, right under the offending wide character.
-- This is not quite right, because characters in general
-- will take more than one character position ???
Error_Msg
("literal out of range of type Standard.Wide_Character",
Source_Ptr (Int (Loc) + J));
return;
end if;
end loop;
-- If the root type is not a standard character, then we will convert
-- the string into an aggregate and will let the aggregate code do
-- the checking. Standard Wide_Wide_Character is also OK here.
else
null;
end if;
-- See if the component type of the array corresponding to the string
-- has compile time known bounds. If yes we can directly check
-- whether the evaluation of the string will raise constraint error.
-- Otherwise we need to transform the string literal into the
-- corresponding character aggregate and let the aggregate code do
-- the checking. We use the same transformation if the component
-- type has a static predicate, which will be applied to each
-- character when the aggregate is resolved.
if Is_Standard_Character_Type (R_Typ) then
-- Check for the case of full range, where we are definitely OK
if Component_Type (Typ) = Base_Type (Component_Type (Typ)) then
return;
end if;
-- Here the range is not the complete base type range, so check
declare
Comp_Typ_Lo : constant Node_Id :=
Type_Low_Bound (Component_Type (Typ));
Comp_Typ_Hi : constant Node_Id :=
Type_High_Bound (Component_Type (Typ));
Char_Val : Uint;
begin
if Compile_Time_Known_Value (Comp_Typ_Lo)
and then Compile_Time_Known_Value (Comp_Typ_Hi)
then
for J in 1 .. Strlen loop
Char_Val := UI_From_Int (Int (Get_String_Char (Str, J)));
if Char_Val < Expr_Value (Comp_Typ_Lo)
or else Char_Val > Expr_Value (Comp_Typ_Hi)
then
Apply_Compile_Time_Constraint_Error
(N, "character out of range??",
CE_Range_Check_Failed,
Loc => Source_Ptr (Int (Loc) + J));
end if;
end loop;
if not Has_Static_Predicate (C_Typ) then
return;
end if;
end if;
end;
end if;
end if;
-- If we got here we meed to transform the string literal into the
-- equivalent qualified positional array aggregate. This is rather
-- heavy artillery for this situation, but it is hard work to avoid.
declare
Lits : constant List_Id := New_List;
P : Source_Ptr := Loc + 1;
C : Char_Code;
begin
-- Build the character literals, we give them source locations that
-- correspond to the string positions, which is a bit tricky given
-- the possible presence of wide character escape sequences.
for J in 1 .. Strlen loop
C := Get_String_Char (Str, J);
Set_Character_Literal_Name (C);
Append_To (Lits,
Make_Character_Literal (P,
Chars => Name_Find,
Char_Literal_Value => UI_From_CC (C)));
if In_Character_Range (C) then
P := P + 1;
-- Should we have a call to Skip_Wide here ???
-- ??? else
-- Skip_Wide (P);
end if;
end loop;
Rewrite (N,
Make_Qualified_Expression (Loc,
Subtype_Mark => New_Occurrence_Of (Typ, Loc),
Expression =>
Make_Aggregate (Loc, Expressions => Lits)));
Analyze_And_Resolve (N, Typ);
end;
end Resolve_String_Literal;
-------------------------
-- Resolve_Target_Name --
-------------------------
procedure Resolve_Target_Name (N : Node_Id; Typ : Entity_Id) is
begin
Set_Etype (N, Typ);
end Resolve_Target_Name;
-----------------------------
-- Resolve_Type_Conversion --
-----------------------------
procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id) is
Conv_OK : constant Boolean := Conversion_OK (N);
Operand : constant Node_Id := Expression (N);
Operand_Typ : constant Entity_Id := Etype (Operand);
Target_Typ : constant Entity_Id := Etype (N);
Rop : Node_Id;
Orig_N : Node_Id;
Orig_T : Node_Id;
Test_Redundant : Boolean := Warn_On_Redundant_Constructs;
-- Set to False to suppress cases where we want to suppress the test
-- for redundancy to avoid possible false positives on this warning.
begin
if not Conv_OK
and then not Valid_Conversion (N, Target_Typ, Operand)
then
return;
end if;
-- If the Operand Etype is Universal_Fixed, then the conversion is
-- never redundant. We need this check because by the time we have
-- finished the rather complex transformation, the conversion looks
-- redundant when it is not.
if Operand_Typ = Universal_Fixed then
Test_Redundant := False;
-- If the operand is marked as Any_Fixed, then special processing is
-- required. This is also a case where we suppress the test for a
-- redundant conversion, since most certainly it is not redundant.
elsif Operand_Typ = Any_Fixed then
Test_Redundant := False;
-- Mixed-mode operation involving a literal. Context must be a fixed
-- type which is applied to the literal subsequently.
-- Multiplication and division involving two fixed type operands must
-- yield a universal real because the result is computed in arbitrary
-- precision.
if Is_Fixed_Point_Type (Typ)
and then Nkind (Operand) in N_Op_Divide | N_Op_Multiply
and then Etype (Left_Opnd (Operand)) = Any_Fixed
and then Etype (Right_Opnd (Operand)) = Any_Fixed
then
Set_Etype (Operand, Universal_Real);
elsif Is_Numeric_Type (Typ)
and then Nkind (Operand) in N_Op_Multiply | N_Op_Divide
and then (Etype (Right_Opnd (Operand)) = Universal_Real
or else
Etype (Left_Opnd (Operand)) = Universal_Real)
then
-- Return if expression is ambiguous
if Unique_Fixed_Point_Type (N) = Any_Type then
return;
-- If nothing else, the available fixed type is Duration
else
Set_Etype (Operand, Standard_Duration);
end if;
-- Resolve the real operand with largest available precision
if Etype (Right_Opnd (Operand)) = Universal_Real then
Rop := New_Copy_Tree (Right_Opnd (Operand));
else
Rop := New_Copy_Tree (Left_Opnd (Operand));
end if;
Resolve (Rop, Universal_Real);
-- If the operand is a literal (it could be a non-static and
-- illegal exponentiation) check whether the use of Duration
-- is potentially inaccurate.
if Nkind (Rop) = N_Real_Literal
and then Realval (Rop) /= Ureal_0
and then abs (Realval (Rop)) < Delta_Value (Standard_Duration)
then
Error_Msg_N
("??universal real operand can only "
& "be interpreted as Duration!", Rop);
Error_Msg_N
("\??precision will be lost in the conversion!", Rop);
end if;
elsif Is_Numeric_Type (Typ)
and then Nkind (Operand) in N_Op
and then Unique_Fixed_Point_Type (N) /= Any_Type
then
Set_Etype (Operand, Standard_Duration);
else
Error_Msg_N ("invalid context for mixed mode operation", N);
Set_Etype (Operand, Any_Type);
return;
end if;
end if;
Resolve (Operand);
Analyze_Dimension (N);
-- Note: we do the Eval_Type_Conversion call before applying the
-- required checks for a subtype conversion. This is important, since
-- both are prepared under certain circumstances to change the type
-- conversion to a constraint error node, but in the case of
-- Eval_Type_Conversion this may reflect an illegality in the static
-- case, and we would miss the illegality (getting only a warning
-- message), if we applied the type conversion checks first.
Eval_Type_Conversion (N);
-- Even when evaluation is not possible, we may be able to simplify the
-- conversion or its expression. This needs to be done before applying
-- checks, since otherwise the checks may use the original expression
-- and defeat the simplifications. This is specifically the case for
-- elimination of the floating-point Truncation attribute in
-- float-to-int conversions.
Simplify_Type_Conversion (N);
-- If after evaluation we still have a type conversion, then we may need
-- to apply checks required for a subtype conversion. But skip them if
-- universal fixed operands are involved, since range checks are handled
-- separately for these cases, after the expansion done by Exp_Fixd.
if Nkind (N) = N_Type_Conversion
and then not Is_Generic_Type (Root_Type (Target_Typ))
and then Target_Typ /= Universal_Fixed
and then Etype (Operand) /= Universal_Fixed
then
Apply_Type_Conversion_Checks (N);
end if;
-- Issue warning for conversion of simple object to its own type. We
-- have to test the original nodes, since they may have been rewritten
-- by various optimizations.
Orig_N := Original_Node (N);
-- Here we test for a redundant conversion if the warning mode is
-- active (and was not locally reset), and we have a type conversion
-- from source not appearing in a generic instance.
if Test_Redundant
and then Nkind (Orig_N) = N_Type_Conversion
and then Comes_From_Source (Orig_N)
and then not In_Instance
then
Orig_N := Original_Node (Expression (Orig_N));
Orig_T := Target_Typ;
-- If the node is part of a larger expression, the Target_Type
-- may not be the original type of the node if the context is a
-- condition. Recover original type to see if conversion is needed.
if Is_Boolean_Type (Orig_T)
and then Nkind (Parent (N)) in N_Op
then
Orig_T := Etype (Parent (N));
end if;
-- If we have an entity name, then give the warning if the entity
-- is the right type, or if it is a loop parameter covered by the
-- original type (that's needed because loop parameters have an
-- odd subtype coming from the bounds).
if (Is_Entity_Name (Orig_N)
and then Present (Entity (Orig_N))
and then
(Etype (Entity (Orig_N)) = Orig_T
or else
(Ekind (Entity (Orig_N)) = E_Loop_Parameter
and then Covers (Orig_T, Etype (Entity (Orig_N))))))
-- If not an entity, then type of expression must match
or else Etype (Orig_N) = Orig_T
then
-- One more check, do not give warning if the analyzed conversion
-- has an expression with non-static bounds, and the bounds of the
-- target are static. This avoids junk warnings in cases where the
-- conversion is necessary to establish staticness, for example in
-- a case statement.
if not Is_OK_Static_Subtype (Operand_Typ)
and then Is_OK_Static_Subtype (Target_Typ)
then
null;
-- Finally, if this type conversion occurs in a context requiring
-- a prefix, and the expression is a qualified expression then the
-- type conversion is not redundant, since a qualified expression
-- is not a prefix, whereas a type conversion is. For example, "X
-- := T'(Funx(...)).Y;" is illegal because a selected component
-- requires a prefix, but a type conversion makes it legal: "X :=
-- T(T'(Funx(...))).Y;"
-- In Ada 2012, a qualified expression is a name, so this idiom is
-- no longer needed, but we still suppress the warning because it
-- seems unfriendly for warnings to pop up when you switch to the
-- newer language version.
elsif Nkind (Orig_N) = N_Qualified_Expression
and then Nkind (Parent (N)) in N_Attribute_Reference
| N_Indexed_Component
| N_Selected_Component
| N_Slice
| N_Explicit_Dereference
then
null;
-- Never warn on conversion to Long_Long_Integer'Base since
-- that is most likely an artifact of the extended overflow
-- checking and comes from complex expanded code.
elsif Orig_T = Base_Type (Standard_Long_Long_Integer) then
null;
-- Here we give the redundant conversion warning. If it is an
-- entity, give the name of the entity in the message. If not,
-- just mention the expression.
else
if Is_Entity_Name (Orig_N) then
Error_Msg_Node_2 := Orig_T;
Error_Msg_NE -- CODEFIX
("?r?redundant conversion, & is of type &!",
N, Entity (Orig_N));
else
Error_Msg_NE
("?r?redundant conversion, expression is of type&!",
N, Orig_T);
end if;
end if;
end if;
end if;
-- Ada 2005 (AI-251): Handle class-wide interface type conversions.
-- No need to perform any interface conversion if the type of the
-- expression coincides with the target type.
if Ada_Version >= Ada_2005
and then Expander_Active
and then Operand_Typ /= Target_Typ
then
declare
Opnd : Entity_Id := Operand_Typ;
Target : Entity_Id := Target_Typ;
begin
-- If the type of the operand is a limited view, use nonlimited
-- view when available. If it is a class-wide type, recover the
-- class-wide type of the nonlimited view.
if From_Limited_With (Opnd)
and then Has_Non_Limited_View (Opnd)
then
Opnd := Non_Limited_View (Opnd);
Set_Etype (Expression (N), Opnd);
end if;
-- It seems that Non_Limited_View should also be applied for
-- Target when it has a limited view, but that leads to missing
-- error checks on interface conversions further below. ???
if Is_Access_Type (Opnd) then
Opnd := Designated_Type (Opnd);
-- If the type of the operand is a limited view, use nonlimited
-- view when available. If it is a class-wide type, recover the
-- class-wide type of the nonlimited view.
if From_Limited_With (Opnd)
and then Has_Non_Limited_View (Opnd)
then
Opnd := Non_Limited_View (Opnd);
end if;
end if;
if Is_Access_Type (Target_Typ) then
Target := Designated_Type (Target);
-- If the target type is a limited view, use nonlimited view
-- when available.
if From_Limited_With (Target)
and then Has_Non_Limited_View (Target)
then
Target := Non_Limited_View (Target);
end if;
end if;
if Opnd = Target then
null;
-- Conversion from interface type
-- It seems that it would be better for the error checks below
-- to be performed as part of Validate_Conversion (and maybe some
-- of the error checks above could be moved as well?). ???
elsif Is_Interface (Opnd) then
-- Ada 2005 (AI-217): Handle entities from limited views
if From_Limited_With (Opnd) then
Error_Msg_Qual_Level := 99;
Error_Msg_NE -- CODEFIX
("missing WITH clause on package &", N,
Cunit_Entity (Get_Source_Unit (Base_Type (Opnd))));
Error_Msg_N
("type conversions require visibility of the full view",
N);
elsif From_Limited_With (Target)
and then not
(Is_Access_Type (Target_Typ)
and then Present (Non_Limited_View (Etype (Target))))
then
Error_Msg_Qual_Level := 99;
Error_Msg_NE -- CODEFIX
("missing WITH clause on package &", N,
Cunit_Entity (Get_Source_Unit (Base_Type (Target))));
Error_Msg_N
("type conversions require visibility of the full view",
N);
else
Expand_Interface_Conversion (N);
end if;
-- Conversion to interface type
elsif Is_Interface (Target) then
-- Handle subtypes
if Ekind (Opnd) in E_Protected_Subtype | E_Task_Subtype then
Opnd := Etype (Opnd);
end if;
if Is_Class_Wide_Type (Opnd)
or else Interface_Present_In_Ancestor
(Typ => Opnd,
Iface => Target)
then
Expand_Interface_Conversion (N);
else
Error_Msg_Name_1 := Chars (Etype (Target));
Error_Msg_Name_2 := Chars (Opnd);
Error_Msg_N
("wrong interface conversion (% is not a progenitor "
& "of %)", N);
end if;
end if;
end;
end if;
-- Ada 2012: Once the type conversion is resolved, check whether the
-- operand statisfies a static predicate of the target subtype, if any.
-- In the static expression case, a predicate check failure is an error.
if Has_Predicates (Target_Typ) then
Check_Expression_Against_Static_Predicate
(N, Target_Typ, Static_Failure_Is_Error => True);
end if;
-- If at this stage we have a fixed to integer conversion, make sure the
-- Do_Range_Check flag is set, because such conversions in general need
-- a range check. We only need this if expansion is off, see above why.
if Nkind (N) = N_Type_Conversion
and then not Expander_Active
and then Is_Integer_Type (Target_Typ)
and then Is_Fixed_Point_Type (Operand_Typ)
and then not Range_Checks_Suppressed (Target_Typ)
and then not Range_Checks_Suppressed (Operand_Typ)
then
Set_Do_Range_Check (Operand);
end if;
-- Generating C code a type conversion of an access to constrained
-- array type to access to unconstrained array type involves building
-- a fat pointer which in general cannot be generated on the fly. We
-- remove side effects in order to store the result of the conversion
-- into a temporary.
if Modify_Tree_For_C
and then Nkind (N) = N_Type_Conversion
and then Nkind (Parent (N)) /= N_Object_Declaration
and then Is_Access_Type (Etype (N))
and then Is_Array_Type (Designated_Type (Etype (N)))
and then not Is_Constrained (Designated_Type (Etype (N)))
and then Is_Constrained (Designated_Type (Etype (Expression (N))))
then
Remove_Side_Effects (N);
end if;
end Resolve_Type_Conversion;
----------------------
-- Resolve_Unary_Op --
----------------------
procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
R : constant Node_Id := Right_Opnd (N);
OK : Boolean;
Lo : Uint;
Hi : Uint;
begin
-- Deal with intrinsic unary operators
if Comes_From_Source (N)
and then Ekind (Entity (N)) = E_Function
and then Is_Imported (Entity (N))
and then Is_Intrinsic_Subprogram (Entity (N))
then
Resolve_Intrinsic_Unary_Operator (N, Typ);
return;
end if;
-- Deal with universal cases
if Etype (R) = Universal_Integer
or else
Etype (R) = Universal_Real
then
Check_For_Visible_Operator (N, B_Typ);
end if;
Set_Etype (N, B_Typ);
Resolve (R, B_Typ);
-- Generate warning for expressions like abs (x mod 2)
if Warn_On_Redundant_Constructs
and then Nkind (N) = N_Op_Abs
then
Determine_Range (Right_Opnd (N), OK, Lo, Hi);
if OK and then Hi >= Lo and then Lo >= 0 then
Error_Msg_N -- CODEFIX
("?r?abs applied to known non-negative value has no effect", N);
end if;
end if;
-- Deal with reference generation
Check_Unset_Reference (R);
Generate_Operator_Reference (N, B_Typ);
Analyze_Dimension (N);
Eval_Unary_Op (N);
-- Set overflow checking bit. Much cleverer code needed here eventually
-- and perhaps the Resolve routines should be separated for the various
-- arithmetic operations, since they will need different processing ???
if Nkind (N) in N_Op then
if not Overflow_Checks_Suppressed (Etype (N)) then
Enable_Overflow_Check (N);
end if;
end if;
-- Generate warning for expressions like -5 mod 3 for integers. No need
-- to worry in the floating-point case, since parens do not affect the
-- result so there is no point in giving in a warning.
declare
Norig : constant Node_Id := Original_Node (N);
Rorig : Node_Id;
Val : Uint;
HB : Uint;
LB : Uint;
Lval : Uint;
Opnd : Node_Id;
begin
if Warn_On_Questionable_Missing_Parens
and then Comes_From_Source (Norig)
and then Is_Integer_Type (Typ)
and then Nkind (Norig) = N_Op_Minus
then
Rorig := Original_Node (Right_Opnd (Norig));
-- We are looking for cases where the right operand is not
-- parenthesized, and is a binary operator, multiply, divide, or
-- mod. These are the cases where the grouping can affect results.
if Paren_Count (Rorig) = 0
and then Nkind (Rorig) in N_Op_Mod | N_Op_Multiply | N_Op_Divide
then
-- For mod, we always give the warning, since the value is
-- affected by the parenthesization (e.g. (-5) mod 315 /=
-- -(5 mod 315)). But for the other cases, the only concern is
-- overflow, e.g. for the case of 8 big signed (-(2 * 64)
-- overflows, but (-2) * 64 does not). So we try to give the
-- message only when overflow is possible.
if Nkind (Rorig) /= N_Op_Mod
and then Compile_Time_Known_Value (R)
then
Val := Expr_Value (R);
if Compile_Time_Known_Value (Type_High_Bound (Typ)) then
HB := Expr_Value (Type_High_Bound (Typ));
else
HB := Expr_Value (Type_High_Bound (Base_Type (Typ)));
end if;
if Compile_Time_Known_Value (Type_Low_Bound (Typ)) then
LB := Expr_Value (Type_Low_Bound (Typ));
else
LB := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
end if;
-- Note that the test below is deliberately excluding the
-- largest negative number, since that is a potentially
-- troublesome case (e.g. -2 * x, where the result is the
-- largest negative integer has an overflow with 2 * x).
if Val > LB and then Val <= HB then
return;
end if;
end if;
-- For the multiplication case, the only case we have to worry
-- about is when (-a)*b is exactly the largest negative number
-- so that -(a*b) can cause overflow. This can only happen if
-- a is a power of 2, and more generally if any operand is a
-- constant that is not a power of 2, then the parentheses
-- cannot affect whether overflow occurs. We only bother to
-- test the left most operand
-- Loop looking at left operands for one that has known value
Opnd := Rorig;
Opnd_Loop : while Nkind (Opnd) = N_Op_Multiply loop
if Compile_Time_Known_Value (Left_Opnd (Opnd)) then
Lval := UI_Abs (Expr_Value (Left_Opnd (Opnd)));
-- Operand value of 0 or 1 skips warning
if Lval <= 1 then
return;
-- Otherwise check power of 2, if power of 2, warn, if
-- anything else, skip warning.
else
while Lval /= 2 loop
if Lval mod 2 = 1 then
return;
else
Lval := Lval / 2;
end if;
end loop;
exit Opnd_Loop;
end if;
end if;
-- Keep looking at left operands
Opnd := Left_Opnd (Opnd);
end loop Opnd_Loop;
-- For rem or "/" we can only have a problematic situation
-- if the divisor has a value of minus one or one. Otherwise
-- overflow is impossible (divisor > 1) or we have a case of
-- division by zero in any case.
if Nkind (Rorig) in N_Op_Divide | N_Op_Rem
and then Compile_Time_Known_Value (Right_Opnd (Rorig))
and then UI_Abs (Expr_Value (Right_Opnd (Rorig))) /= 1
then
return;
end if;
-- If we fall through warning should be issued
-- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
Error_Msg_N
("??unary minus expression should be parenthesized here!", N);
end if;
end if;
end;
end Resolve_Unary_Op;
----------------------------------
-- Resolve_Unchecked_Expression --
----------------------------------
procedure Resolve_Unchecked_Expression
(N : Node_Id;
Typ : Entity_Id)
is
begin
Resolve (Expression (N), Typ, Suppress => All_Checks);
Set_Etype (N, Typ);
end Resolve_Unchecked_Expression;
---------------------------------------
-- Resolve_Unchecked_Type_Conversion --
---------------------------------------
procedure Resolve_Unchecked_Type_Conversion
(N : Node_Id;
Typ : Entity_Id)
is
pragma Warnings (Off, Typ);
Operand : constant Node_Id := Expression (N);
Opnd_Type : constant Entity_Id := Etype (Operand);
begin
-- Resolve operand using its own type
Resolve (Operand, Opnd_Type);
-- If the expression is a conversion to universal integer of an
-- an expression with an integer type, then we can eliminate the
-- intermediate conversion to universal integer.
if Nkind (Operand) = N_Type_Conversion
and then Entity (Subtype_Mark (Operand)) = Universal_Integer
and then Is_Integer_Type (Etype (Expression (Operand)))
then
Rewrite (Operand, Relocate_Node (Expression (Operand)));
Analyze_And_Resolve (Operand);
end if;
-- In an inlined context, the unchecked conversion may be applied
-- to a literal, in which case its type is the type of the context.
-- (In other contexts conversions cannot apply to literals).
if In_Inlined_Body
and then (Opnd_Type = Any_Character or else
Opnd_Type = Any_Integer or else
Opnd_Type = Any_Real)
then
Set_Etype (Operand, Typ);
end if;
Analyze_Dimension (N);
Eval_Unchecked_Conversion (N);
end Resolve_Unchecked_Type_Conversion;
------------------------------
-- Rewrite_Operator_As_Call --
------------------------------
procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
Actuals : constant List_Id := New_List;
New_N : Node_Id;
begin
if Nkind (N) in N_Binary_Op then
Append (Left_Opnd (N), Actuals);
end if;
Append (Right_Opnd (N), Actuals);
New_N :=
Make_Function_Call (Sloc => Loc,
Name => New_Occurrence_Of (Nam, Loc),
Parameter_Associations => Actuals);
Preserve_Comes_From_Source (New_N, N);
Preserve_Comes_From_Source (Name (New_N), N);
Rewrite (N, New_N);
Set_Etype (N, Etype (Nam));
end Rewrite_Operator_As_Call;
------------------------------
-- Rewrite_Renamed_Operator --
------------------------------
procedure Rewrite_Renamed_Operator
(N : Node_Id;
Op : Entity_Id;
Typ : Entity_Id)
is
Nam : constant Name_Id := Chars (Op);
Is_Binary : constant Boolean := Nkind (N) in N_Binary_Op;
Op_Node : Node_Id;
begin
-- Do not perform this transformation within a pre/postcondition,
-- because the expression will be reanalyzed, and the transformation
-- might affect the visibility of the operator, e.g. in an instance.
-- Note that fully analyzed and expanded pre/postconditions appear as
-- pragma Check equivalents.
if In_Pre_Post_Condition (N) then
return;
end if;
-- Likewise when an expression function is being preanalyzed, since the
-- expression will be reanalyzed as part of the generated body.
if In_Spec_Expression then
declare
S : constant Entity_Id := Current_Scope_No_Loops;
begin
if Ekind (S) = E_Function
and then Nkind (Original_Node (Unit_Declaration_Node (S))) =
N_Expression_Function
then
return;
end if;
end;
end if;
-- Rewrite the operator node using the real operator, not its renaming.
-- Exclude user-defined intrinsic operations of the same name, which are
-- treated separately and rewritten as calls.
if Ekind (Op) /= E_Function or else Chars (N) /= Nam then
Op_Node := New_Node (Operator_Kind (Nam, Is_Binary), Sloc (N));
Set_Chars (Op_Node, Nam);
Set_Etype (Op_Node, Etype (N));
Set_Entity (Op_Node, Op);
Set_Right_Opnd (Op_Node, Right_Opnd (N));
-- Indicate that both the original entity and its renaming are
-- referenced at this point.
Generate_Reference (Entity (N), N);
Generate_Reference (Op, N);
if Is_Binary then
Set_Left_Opnd (Op_Node, Left_Opnd (N));
end if;
Rewrite (N, Op_Node);
-- If the context type is private, add the appropriate conversions so
-- that the operator is applied to the full view. This is done in the
-- routines that resolve intrinsic operators.
if Is_Intrinsic_Subprogram (Op) and then Is_Private_Type (Typ) then
case Nkind (N) is
when N_Op_Add
| N_Op_Divide
| N_Op_Expon
| N_Op_Mod
| N_Op_Multiply
| N_Op_Rem
| N_Op_Subtract
=>
Resolve_Intrinsic_Operator (N, Typ);
when N_Op_Abs
| N_Op_Minus
| N_Op_Plus
=>
Resolve_Intrinsic_Unary_Operator (N, Typ);
when others =>
Resolve (N, Typ);
end case;
end if;
elsif Ekind (Op) = E_Function and then Is_Intrinsic_Subprogram (Op) then
-- Operator renames a user-defined operator of the same name. Use the
-- original operator in the node, which is the one Gigi knows about.
Set_Entity (N, Op);
Set_Is_Overloaded (N, False);
end if;
end Rewrite_Renamed_Operator;
-----------------------
-- Set_Slice_Subtype --
-----------------------
-- Build an implicit subtype declaration to represent the type delivered by
-- the slice. This is an abbreviated version of an array subtype. We define
-- an index subtype for the slice, using either the subtype name or the
-- discrete range of the slice. To be consistent with index usage elsewhere
-- we create a list header to hold the single index. This list is not
-- otherwise attached to the syntax tree.
procedure Set_Slice_Subtype (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Index_List : constant List_Id := New_List;
Index : Node_Id;
Index_Subtype : Entity_Id;
Index_Type : Entity_Id;
Slice_Subtype : Entity_Id;
Drange : constant Node_Id := Discrete_Range (N);
begin
Index_Type := Base_Type (Etype (Drange));
if Is_Entity_Name (Drange) then
Index_Subtype := Entity (Drange);
else
-- We force the evaluation of a range. This is definitely needed in
-- the renamed case, and seems safer to do unconditionally. Note in
-- any case that since we will create and insert an Itype referring
-- to this range, we must make sure any side effect removal actions
-- are inserted before the Itype definition.
if Nkind (Drange) = N_Range then
Force_Evaluation (Low_Bound (Drange));
Force_Evaluation (High_Bound (Drange));
-- If the discrete range is given by a subtype indication, the
-- type of the slice is the base of the subtype mark.
elsif Nkind (Drange) = N_Subtype_Indication then
declare
R : constant Node_Id := Range_Expression (Constraint (Drange));
begin
Index_Type := Base_Type (Entity (Subtype_Mark (Drange)));
Force_Evaluation (Low_Bound (R));
Force_Evaluation (High_Bound (R));
end;
end if;
Index_Subtype := Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
-- Take a new copy of Drange (where bounds have been rewritten to
-- reference side-effect-free names). Using a separate tree ensures
-- that further expansion (e.g. while rewriting a slice assignment
-- into a FOR loop) does not attempt to remove side effects on the
-- bounds again (which would cause the bounds in the index subtype
-- definition to refer to temporaries before they are defined) (the
-- reason is that some names are considered side effect free here
-- for the subtype, but not in the context of a loop iteration
-- scheme).
Set_Scalar_Range (Index_Subtype, New_Copy_Tree (Drange));
Set_Parent (Scalar_Range (Index_Subtype), Index_Subtype);
Set_Etype (Index_Subtype, Index_Type);
Set_Size_Info (Index_Subtype, Index_Type);
Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
Set_Is_Constrained (Index_Subtype);
end if;
Slice_Subtype := Create_Itype (E_Array_Subtype, N);
Index := New_Occurrence_Of (Index_Subtype, Loc);
Set_Etype (Index, Index_Subtype);
Append (Index, Index_List);
Set_First_Index (Slice_Subtype, Index);
Set_Etype (Slice_Subtype, Base_Type (Etype (N)));
Set_Is_Constrained (Slice_Subtype, True);
Check_Compile_Time_Size (Slice_Subtype);
-- The Etype of the existing Slice node is reset to this slice subtype.
-- Its bounds are obtained from its first index.
Set_Etype (N, Slice_Subtype);
-- For bit-packed slice subtypes, freeze immediately (except in the case
-- of being in a "spec expression" where we never freeze when we first
-- see the expression).
if Is_Bit_Packed_Array (Slice_Subtype) and not In_Spec_Expression then
Freeze_Itype (Slice_Subtype, N);
-- For all other cases insert an itype reference in the slice's actions
-- so that the itype is frozen at the proper place in the tree (i.e. at
-- the point where actions for the slice are analyzed). Note that this
-- is different from freezing the itype immediately, which might be
-- premature (e.g. if the slice is within a transient scope). This needs
-- to be done only if expansion is enabled, or in GNATprove mode to
-- capture the associated run-time exceptions if any.
elsif Expander_Active or GNATprove_Mode then
Ensure_Defined (Typ => Slice_Subtype, N => N);
end if;
end Set_Slice_Subtype;
--------------------------------
-- Set_String_Literal_Subtype --
--------------------------------
procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
Low_Bound : constant Node_Id :=
Type_Low_Bound (Etype (First_Index (Typ)));
Subtype_Id : Entity_Id;
begin
if Nkind (N) /= N_String_Literal then
return;
end if;
Subtype_Id := Create_Itype (E_String_Literal_Subtype, N);
Set_String_Literal_Length (Subtype_Id, UI_From_Int
(String_Length (Strval (N))));
Set_Etype (Subtype_Id, Base_Type (Typ));
Set_Is_Constrained (Subtype_Id);
Set_Etype (N, Subtype_Id);
-- The low bound is set from the low bound of the corresponding index
-- type. Note that we do not store the high bound in the string literal
-- subtype, but it can be deduced if necessary from the length and the
-- low bound.
if Is_OK_Static_Expression (Low_Bound) then
Set_String_Literal_Low_Bound (Subtype_Id, Low_Bound);
-- If the lower bound is not static we create a range for the string
-- literal, using the index type and the known length of the literal.
-- If the length is 1, then the upper bound is set to a mere copy of
-- the lower bound; or else, if the index type is a signed integer,
-- then the upper bound is computed as Low_Bound + L - 1; otherwise,
-- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
else
declare
Length : constant Nat := String_Length (Strval (N));
Index_List : constant List_Id := New_List;
Index_Type : constant Entity_Id := Etype (First_Index (Typ));
Array_Subtype : Entity_Id;
Drange : Node_Id;
High_Bound : Node_Id;
Index : Node_Id;
Index_Subtype : Entity_Id;
begin
if Length = 1 then
High_Bound := New_Copy_Tree (Low_Bound);
elsif Is_Signed_Integer_Type (Index_Type) then
High_Bound :=
Make_Op_Add (Loc,
Left_Opnd => New_Copy_Tree (Low_Bound),
Right_Opnd => Make_Integer_Literal (Loc, Length - 1));
else
High_Bound :=
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Val,
Prefix =>
New_Occurrence_Of (Index_Type, Loc),
Expressions => New_List (
Make_Op_Add (Loc,
Left_Opnd =>
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Pos,
Prefix =>
New_Occurrence_Of (Index_Type, Loc),
Expressions =>
New_List (New_Copy_Tree (Low_Bound))),
Right_Opnd =>
Make_Integer_Literal (Loc, Length - 1))));
end if;
if Is_Integer_Type (Index_Type) then
Set_String_Literal_Low_Bound
(Subtype_Id, Make_Integer_Literal (Loc, 1));
else
-- If the index type is an enumeration type, build bounds
-- expression with attributes.
Set_String_Literal_Low_Bound
(Subtype_Id,
Make_Attribute_Reference (Loc,
Attribute_Name => Name_First,
Prefix =>
New_Occurrence_Of (Base_Type (Index_Type), Loc)));
end if;
Analyze_And_Resolve
(String_Literal_Low_Bound (Subtype_Id), Base_Type (Index_Type));
-- Build bona fide subtype for the string, and wrap it in an
-- unchecked conversion, because the back end expects the
-- String_Literal_Subtype to have a static lower bound.
Index_Subtype :=
Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
Drange := Make_Range (Loc, New_Copy_Tree (Low_Bound), High_Bound);
Set_Scalar_Range (Index_Subtype, Drange);
Set_Parent (Drange, N);
Analyze_And_Resolve (Drange, Index_Type);
-- In this context, the Index_Type may already have a constraint,
-- so use common base type on string subtype. The base type may
-- be used when generating attributes of the string, for example
-- in the context of a slice assignment.
Set_Etype (Index_Subtype, Base_Type (Index_Type));
Set_Size_Info (Index_Subtype, Index_Type);
Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
Array_Subtype := Create_Itype (E_Array_Subtype, N);
Index := New_Occurrence_Of (Index_Subtype, Loc);
Set_Etype (Index, Index_Subtype);
Append (Index, Index_List);
Set_First_Index (Array_Subtype, Index);
Set_Etype (Array_Subtype, Base_Type (Typ));
Set_Is_Constrained (Array_Subtype, True);
Rewrite (N,
Make_Unchecked_Type_Conversion (Loc,
Subtype_Mark => New_Occurrence_Of (Array_Subtype, Loc),
Expression => Relocate_Node (N)));
Set_Etype (N, Array_Subtype);
end;
end if;
end Set_String_Literal_Subtype;
------------------------------
-- Simplify_Type_Conversion --
------------------------------
procedure Simplify_Type_Conversion (N : Node_Id) is
begin
if Nkind (N) = N_Type_Conversion then
declare
Operand : constant Node_Id := Expression (N);
Target_Typ : constant Entity_Id := Etype (N);
Opnd_Typ : constant Entity_Id := Etype (Operand);
begin
-- Special processing if the conversion is the expression of a
-- Rounding or Truncation attribute reference. In this case we
-- replace:
-- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
-- by
-- ityp (x)
-- with the Float_Truncate flag set to False or True respectively,
-- which is more efficient. We reuse Rounding for Machine_Rounding
-- as System.Fat_Gen, which is a permissible behavior.
if Is_Floating_Point_Type (Opnd_Typ)
and then
(Is_Integer_Type (Target_Typ)
or else (Is_Fixed_Point_Type (Target_Typ)
and then Conversion_OK (N)))
and then Nkind (Operand) = N_Attribute_Reference
and then Attribute_Name (Operand) in Name_Rounding
| Name_Machine_Rounding
| Name_Truncation
then
declare
Truncate : constant Boolean :=
Attribute_Name (Operand) = Name_Truncation;
begin
Rewrite (Operand,
Relocate_Node (First (Expressions (Operand))));
Set_Float_Truncate (N, Truncate);
end;
-- Special processing for the conversion of an integer literal to
-- a dynamic type: we first convert the literal to the root type
-- and then convert the result to the target type, the goal being
-- to avoid doing range checks in universal integer.
elsif Is_Integer_Type (Target_Typ)
and then not Is_Generic_Type (Root_Type (Target_Typ))
and then Nkind (Operand) = N_Integer_Literal
and then Opnd_Typ = Universal_Integer
then
Convert_To_And_Rewrite (Root_Type (Target_Typ), Operand);
Analyze_And_Resolve (Operand);
-- If the expression is a conversion to universal integer of an
-- an expression with an integer type, then we can eliminate the
-- intermediate conversion to universal integer.
elsif Nkind (Operand) = N_Type_Conversion
and then Entity (Subtype_Mark (Operand)) = Universal_Integer
and then Is_Integer_Type (Etype (Expression (Operand)))
then
Rewrite (Operand, Relocate_Node (Expression (Operand)));
Analyze_And_Resolve (Operand);
end if;
end;
end if;
end Simplify_Type_Conversion;
-----------------------------
-- Unique_Fixed_Point_Type --
-----------------------------
function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id is
procedure Fixed_Point_Error (T1 : Entity_Id; T2 : Entity_Id);
-- Give error messages for true ambiguity. Messages are posted on node
-- N, and entities T1, T2 are the possible interpretations.
-----------------------
-- Fixed_Point_Error --
-----------------------
procedure Fixed_Point_Error (T1 : Entity_Id; T2 : Entity_Id) is
begin
Error_Msg_N ("ambiguous universal_fixed_expression", N);
Error_Msg_NE ("\\possible interpretation as}", N, T1);
Error_Msg_NE ("\\possible interpretation as}", N, T2);
end Fixed_Point_Error;
-- Local variables
ErrN : Node_Id;
Item : Node_Id;
Scop : Entity_Id;
T1 : Entity_Id;
T2 : Entity_Id;
-- Start of processing for Unique_Fixed_Point_Type
begin
-- The operations on Duration are visible, so Duration is always a
-- possible interpretation.
T1 := Standard_Duration;
-- Look for fixed-point types in enclosing scopes
Scop := Current_Scope;
while Scop /= Standard_Standard loop
T2 := First_Entity (Scop);
while Present (T2) loop
if Is_Fixed_Point_Type (T2)
and then Current_Entity (T2) = T2
and then Scope (Base_Type (T2)) = Scop
then
if Present (T1) then
Fixed_Point_Error (T1, T2);
return Any_Type;
else
T1 := T2;
end if;
end if;
Next_Entity (T2);
end loop;
Scop := Scope (Scop);
end loop;
-- Look for visible fixed type declarations in the context
Item := First (Context_Items (Cunit (Current_Sem_Unit)));
while Present (Item) loop
if Nkind (Item) = N_With_Clause then
Scop := Entity (Name (Item));
T2 := First_Entity (Scop);
while Present (T2) loop
if Is_Fixed_Point_Type (T2)
and then Scope (Base_Type (T2)) = Scop
and then (Is_Potentially_Use_Visible (T2) or else In_Use (T2))
then
if Present (T1) then
Fixed_Point_Error (T1, T2);
return Any_Type;
else
T1 := T2;
end if;
end if;
Next_Entity (T2);
end loop;
end if;
Next (Item);
end loop;
if Nkind (N) = N_Real_Literal then
Error_Msg_NE ("??real literal interpreted as }!", N, T1);
else
-- When the context is a type conversion, issue the warning on the
-- expression of the conversion because it is the actual operation.
if Nkind (N) in N_Type_Conversion | N_Unchecked_Type_Conversion then
ErrN := Expression (N);
else
ErrN := N;
end if;
Error_Msg_NE
("??universal_fixed expression interpreted as }!", ErrN, T1);
end if;
return T1;
end Unique_Fixed_Point_Type;
----------------------
-- Valid_Conversion --
----------------------
function Valid_Conversion
(N : Node_Id;
Target : Entity_Id;
Operand : Node_Id;
Report_Errs : Boolean := True) return Boolean
is
Target_Type : constant Entity_Id := Base_Type (Target);
Opnd_Type : Entity_Id := Etype (Operand);
Inc_Ancestor : Entity_Id;
function Conversion_Check
(Valid : Boolean;
Msg : String) return Boolean;
-- Little routine to post Msg if Valid is False, returns Valid value
procedure Conversion_Error_N (Msg : String; N : Node_Or_Entity_Id);
-- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
procedure Conversion_Error_NE
(Msg : String;
N : Node_Or_Entity_Id;
E : Node_Or_Entity_Id);
-- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
function In_Instance_Code return Boolean;
-- Return True if expression is within an instance but is not in one of
-- the actuals of the instantiation. Type conversions within an instance
-- are not rechecked because type visbility may lead to spurious errors,
-- but conversions in an actual for a formal object must be checked.
function Is_Discrim_Of_Bad_Access_Conversion_Argument
(Expr : Node_Id) return Boolean;
-- Implicit anonymous-to-named access type conversions are not allowed
-- if the "statically deeper than" relationship does not apply to the
-- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
-- We deal with most such cases elsewhere so that we can emit more
-- specific error messages (e.g., if the operand is an access parameter
-- or a saooaaat (stand-alone object of an anonymous access type)), but
-- here is where we catch the case where the operand is an access
-- discriminant selected from a dereference of another such "bad"
-- conversion argument.
function Valid_Tagged_Conversion
(Target_Type : Entity_Id;
Opnd_Type : Entity_Id) return Boolean;
-- Specifically test for validity of tagged conversions
function Valid_Array_Conversion return Boolean;
-- Check index and component conformance, and accessibility levels if
-- the component types are anonymous access types (Ada 2005).
----------------------
-- Conversion_Check --
----------------------
function Conversion_Check
(Valid : Boolean;
Msg : String) return Boolean
is
begin
if not Valid
-- A generic unit has already been analyzed and we have verified
-- that a particular conversion is OK in that context. Since the
-- instance is reanalyzed without relying on the relationships
-- established during the analysis of the generic, it is possible
-- to end up with inconsistent views of private types. Do not emit
-- the error message in such cases. The rest of the machinery in
-- Valid_Conversion still ensures the proper compatibility of
-- target and operand types.
and then not In_Instance_Code
then
Conversion_Error_N (Msg, Operand);
end if;
return Valid;
end Conversion_Check;
------------------------
-- Conversion_Error_N --
------------------------
procedure Conversion_Error_N (Msg : String; N : Node_Or_Entity_Id) is
begin
if Report_Errs then
Error_Msg_N (Msg, N);
end if;
end Conversion_Error_N;
-------------------------
-- Conversion_Error_NE --
-------------------------
procedure Conversion_Error_NE
(Msg : String;
N : Node_Or_Entity_Id;
E : Node_Or_Entity_Id)
is
begin
if Report_Errs then
Error_Msg_NE (Msg, N, E);
end if;
end Conversion_Error_NE;
----------------------
-- In_Instance_Code --
----------------------
function In_Instance_Code return Boolean is
Par : Node_Id;
begin
if not In_Instance then
return False;
else
Par := Parent (N);
while Present (Par) loop
-- The expression is part of an actual object if it appears in
-- the generated object declaration in the instance.
if Nkind (Par) = N_Object_Declaration
and then Present (Corresponding_Generic_Association (Par))
then
return False;
else
exit when
Nkind (Par) in N_Statement_Other_Than_Procedure_Call
or else Nkind (Par) in N_Subprogram_Call
or else Nkind (Par) in N_Declaration;
end if;
Par := Parent (Par);
end loop;
-- Otherwise the expression appears within the instantiated unit
return True;
end if;
end In_Instance_Code;
--------------------------------------------------
-- Is_Discrim_Of_Bad_Access_Conversion_Argument --
--------------------------------------------------
function Is_Discrim_Of_Bad_Access_Conversion_Argument
(Expr : Node_Id) return Boolean
is
Exp_Type : Entity_Id := Base_Type (Etype (Expr));
pragma Assert (Is_Access_Type (Exp_Type));
Associated_Node : Node_Id;
Deref_Prefix : Node_Id;
begin
if not Is_Anonymous_Access_Type (Exp_Type) then
return False;
end if;
pragma Assert (Is_Itype (Exp_Type));
Associated_Node := Associated_Node_For_Itype (Exp_Type);
if Nkind (Associated_Node) /= N_Discriminant_Specification then
return False; -- not the type of an access discriminant
end if;
-- return False if Expr not of form <prefix>.all.Some_Component
if (Nkind (Expr) /= N_Selected_Component)
or else (Nkind (Prefix (Expr)) /= N_Explicit_Dereference)
then
-- conditional expressions, declare expressions ???
return False;
end if;
Deref_Prefix := Prefix (Prefix (Expr));
Exp_Type := Base_Type (Etype (Deref_Prefix));
-- The "statically deeper relationship" does not apply
-- to generic formal access types, so a prefix of such
-- a type is a "bad" prefix.
if Is_Generic_Formal (Exp_Type) then
return True;
-- The "statically deeper relationship" does apply to
-- any other named access type.
elsif not Is_Anonymous_Access_Type (Exp_Type) then
return False;
end if;
pragma Assert (Is_Itype (Exp_Type));
Associated_Node := Associated_Node_For_Itype (Exp_Type);
-- The "statically deeper relationship" applies to some
-- anonymous access types and not to others. Return
-- True for the cases where it does not apply. Also check
-- recursively for the
-- <prefix>.all.Access_Discrim.all.Access_Discrim case,
-- where the correct result depends on <prefix>.
return Nkind (Associated_Node) in
N_Procedure_Specification | -- access parameter
N_Function_Specification | -- access parameter
N_Object_Declaration -- saooaaat
or else Is_Discrim_Of_Bad_Access_Conversion_Argument (Deref_Prefix);
end Is_Discrim_Of_Bad_Access_Conversion_Argument;
----------------------------
-- Valid_Array_Conversion --
----------------------------
function Valid_Array_Conversion return Boolean is
Opnd_Comp_Type : constant Entity_Id := Component_Type (Opnd_Type);
Opnd_Comp_Base : constant Entity_Id := Base_Type (Opnd_Comp_Type);
Opnd_Index : Node_Id;
Opnd_Index_Type : Entity_Id;
Target_Comp_Type : constant Entity_Id :=
Component_Type (Target_Type);
Target_Comp_Base : constant Entity_Id :=
Base_Type (Target_Comp_Type);
Target_Index : Node_Id;
Target_Index_Type : Entity_Id;
begin
-- Error if wrong number of dimensions
if
Number_Dimensions (Target_Type) /= Number_Dimensions (Opnd_Type)
then
Conversion_Error_N
("incompatible number of dimensions for conversion", Operand);
return False;
-- Number of dimensions matches
else
-- Loop through indexes of the two arrays
Target_Index := First_Index (Target_Type);
Opnd_Index := First_Index (Opnd_Type);
while Present (Target_Index) and then Present (Opnd_Index) loop
Target_Index_Type := Etype (Target_Index);
Opnd_Index_Type := Etype (Opnd_Index);
-- Error if index types are incompatible
if not (Is_Integer_Type (Target_Index_Type)
and then Is_Integer_Type (Opnd_Index_Type))
and then (Root_Type (Target_Index_Type)
/= Root_Type (Opnd_Index_Type))
then
Conversion_Error_N
("incompatible index types for array conversion",
Operand);
return False;
end if;
Next_Index (Target_Index);
Next_Index (Opnd_Index);
end loop;
-- If component types have same base type, all set
if Target_Comp_Base = Opnd_Comp_Base then
null;
-- Here if base types of components are not the same. The only
-- time this is allowed is if we have anonymous access types.
-- The conversion of arrays of anonymous access types can lead
-- to dangling pointers. AI-392 formalizes the accessibility
-- checks that must be applied to such conversions to prevent
-- out-of-scope references.
elsif Ekind (Target_Comp_Base) in
E_Anonymous_Access_Type
| E_Anonymous_Access_Subprogram_Type
and then Ekind (Opnd_Comp_Base) = Ekind (Target_Comp_Base)
and then
Subtypes_Statically_Match (Target_Comp_Type, Opnd_Comp_Type)
then
if Type_Access_Level (Target_Type) <
Deepest_Type_Access_Level (Opnd_Type)
then
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Conversion_Error_N
("source array type has deeper accessibility "
& "level than target<<", Operand);
Conversion_Error_N ("\Program_Error [<<", Operand);
Rewrite (N,
Make_Raise_Program_Error (Sloc (N),
Reason => PE_Accessibility_Check_Failed));
Set_Etype (N, Target_Type);
return False;
-- Conversion not allowed because of accessibility levels
else
Conversion_Error_N
("source array type has deeper accessibility "
& "level than target", Operand);
return False;
end if;
else
null;
end if;
-- All other cases where component base types do not match
else
Conversion_Error_N
("incompatible component types for array conversion",
Operand);
return False;
end if;
-- Check that component subtypes statically match. For numeric
-- types this means that both must be either constrained or
-- unconstrained. For enumeration types the bounds must match.
-- All of this is checked in Subtypes_Statically_Match.
if not Subtypes_Statically_Match
(Target_Comp_Type, Opnd_Comp_Type)
then
Conversion_Error_N
("component subtypes must statically match", Operand);
return False;
end if;
end if;
return True;
end Valid_Array_Conversion;
-----------------------------
-- Valid_Tagged_Conversion --
-----------------------------
function Valid_Tagged_Conversion
(Target_Type : Entity_Id;
Opnd_Type : Entity_Id) return Boolean
is
begin
-- Upward conversions are allowed (RM 4.6(22))
if Covers (Target_Type, Opnd_Type)
or else Is_Ancestor (Target_Type, Opnd_Type)
then
return True;
-- Downward conversion are allowed if the operand is class-wide
-- (RM 4.6(23)).
elsif Is_Class_Wide_Type (Opnd_Type)
and then Covers (Opnd_Type, Target_Type)
then
return True;
elsif Covers (Opnd_Type, Target_Type)
or else Is_Ancestor (Opnd_Type, Target_Type)
then
return
Conversion_Check (False,
"downward conversion of tagged objects not allowed");
-- Ada 2005 (AI-251): The conversion to/from interface types is
-- always valid. The types involved may be class-wide (sub)types.
elsif Is_Interface (Etype (Base_Type (Target_Type)))
or else Is_Interface (Etype (Base_Type (Opnd_Type)))
then
return True;
-- If the operand is a class-wide type obtained through a limited_
-- with clause, and the context includes the nonlimited view, use
-- it to determine whether the conversion is legal.
elsif Is_Class_Wide_Type (Opnd_Type)
and then From_Limited_With (Opnd_Type)
and then Present (Non_Limited_View (Etype (Opnd_Type)))
and then Is_Interface (Non_Limited_View (Etype (Opnd_Type)))
then
return True;
elsif Is_Access_Type (Opnd_Type)
and then Is_Interface (Directly_Designated_Type (Opnd_Type))
then
return True;
else
Conversion_Error_NE
("invalid tagged conversion, not compatible with}",
N, First_Subtype (Opnd_Type));
return False;
end if;
end Valid_Tagged_Conversion;
-- Start of processing for Valid_Conversion
begin
Check_Parameterless_Call (Operand);
if Is_Overloaded (Operand) then
declare
I : Interp_Index;
I1 : Interp_Index;
It : Interp;
It1 : Interp;
N1 : Entity_Id;
T1 : Entity_Id;
begin
-- Remove procedure calls, which syntactically cannot appear in
-- this context, but which cannot be removed by type checking,
-- because the context does not impose a type.
-- The node may be labelled overloaded, but still contain only one
-- interpretation because others were discarded earlier. If this
-- is the case, retain the single interpretation if legal.
Get_First_Interp (Operand, I, It);
Opnd_Type := It.Typ;
Get_Next_Interp (I, It);
if Present (It.Typ)
and then Opnd_Type /= Standard_Void_Type
then
-- More than one candidate interpretation is available
Get_First_Interp (Operand, I, It);
while Present (It.Typ) loop
if It.Typ = Standard_Void_Type then
Remove_Interp (I);
end if;
-- When compiling for a system where Address is of a visible
-- integer type, spurious ambiguities can be produced when
-- arithmetic operations have a literal operand and return
-- System.Address or a descendant of it. These ambiguities
-- are usually resolved by the context, but for conversions
-- there is no context type and the removal of the spurious
-- operations must be done explicitly here.
if not Address_Is_Private
and then Is_Descendant_Of_Address (It.Typ)
then
Remove_Interp (I);
end if;
Get_Next_Interp (I, It);
end loop;
end if;
Get_First_Interp (Operand, I, It);
I1 := I;
It1 := It;
if No (It.Typ) then
Conversion_Error_N ("illegal operand in conversion", Operand);
return False;
end if;
Get_Next_Interp (I, It);
if Present (It.Typ) then
N1 := It1.Nam;
T1 := It1.Typ;
It1 := Disambiguate (Operand, I1, I, Any_Type);
if It1 = No_Interp then
Conversion_Error_N
("ambiguous operand in conversion", Operand);
-- If the interpretation involves a standard operator, use
-- the location of the type, which may be user-defined.
if Sloc (It.Nam) = Standard_Location then
Error_Msg_Sloc := Sloc (It.Typ);
else
Error_Msg_Sloc := Sloc (It.Nam);
end if;
Conversion_Error_N -- CODEFIX
("\\possible interpretation#!", Operand);
if Sloc (N1) = Standard_Location then
Error_Msg_Sloc := Sloc (T1);
else
Error_Msg_Sloc := Sloc (N1);
end if;
Conversion_Error_N -- CODEFIX
("\\possible interpretation#!", Operand);
return False;
end if;
end if;
Set_Etype (Operand, It1.Typ);
Opnd_Type := It1.Typ;
end;
end if;
-- Deal with conversion of integer type to address if the pragma
-- Allow_Integer_Address is in effect. We convert the conversion to
-- an unchecked conversion in this case and we are all done.
if Address_Integer_Convert_OK (Opnd_Type, Target_Type) then
Rewrite (N, Unchecked_Convert_To (Target_Type, Expression (N)));
Analyze_And_Resolve (N, Target_Type);
return True;
end if;
-- If we are within a child unit, check whether the type of the
-- expression has an ancestor in a parent unit, in which case it
-- belongs to its derivation class even if the ancestor is private.
-- See RM 7.3.1 (5.2/3).
Inc_Ancestor := Get_Incomplete_View_Of_Ancestor (Opnd_Type);
-- Numeric types
if Is_Numeric_Type (Target_Type) then
-- A universal fixed expression can be converted to any numeric type
if Opnd_Type = Universal_Fixed then
return True;
-- Also no need to check when in an instance or inlined body, because
-- the legality has been established when the template was analyzed.
-- Furthermore, numeric conversions may occur where only a private
-- view of the operand type is visible at the instantiation point.
-- This results in a spurious error if we check that the operand type
-- is a numeric type.
-- Note: in a previous version of this unit, the following tests were
-- applied only for generated code (Comes_From_Source set to False),
-- but in fact the test is required for source code as well, since
-- this situation can arise in source code.
elsif In_Instance_Code or else In_Inlined_Body then
return True;
-- Otherwise we need the conversion check
else
return Conversion_Check
(Is_Numeric_Type (Opnd_Type)
or else
(Present (Inc_Ancestor)
and then Is_Numeric_Type (Inc_Ancestor)),
"illegal operand for numeric conversion");
end if;
-- Array types
elsif Is_Array_Type (Target_Type) then
if not Is_Array_Type (Opnd_Type)
or else Opnd_Type = Any_Composite
or else Opnd_Type = Any_String
then
Conversion_Error_N
("illegal operand for array conversion", Operand);
return False;
else
return Valid_Array_Conversion;
end if;
-- Ada 2005 (AI-251): Internally generated conversions of access to
-- interface types added to force the displacement of the pointer to
-- reference the corresponding dispatch table.
elsif not Comes_From_Source (N)
and then Is_Access_Type (Target_Type)
and then Is_Interface (Designated_Type (Target_Type))
then
return True;
-- Ada 2005 (AI-251): Anonymous access types where target references an
-- interface type.
elsif Is_Access_Type (Opnd_Type)
and then Ekind (Target_Type) in
E_General_Access_Type | E_Anonymous_Access_Type
and then Is_Interface (Directly_Designated_Type (Target_Type))
then
-- Check the static accessibility rule of 4.6(17). Note that the
-- check is not enforced when within an instance body, since the
-- RM requires such cases to be caught at run time.
-- If the operand is a rewriting of an allocator no check is needed
-- because there are no accessibility issues.
if Nkind (Original_Node (N)) = N_Allocator then
null;
elsif Ekind (Target_Type) /= E_Anonymous_Access_Type then
if Type_Access_Level (Opnd_Type) >
Deepest_Type_Access_Level (Target_Type)
then
-- In an instance, this is a run-time check, but one we know
-- will fail, so generate an appropriate warning. The raise
-- will be generated by Expand_N_Type_Conversion.
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Conversion_Error_N
("cannot convert local pointer to non-local access type<<",
Operand);
Conversion_Error_N ("\Program_Error [<<", Operand);
else
Conversion_Error_N
("cannot convert local pointer to non-local access type",
Operand);
return False;
end if;
-- Special accessibility checks are needed in the case of access
-- discriminants declared for a limited type.
elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type
and then not Is_Local_Anonymous_Access (Opnd_Type)
then
-- When the operand is a selected access discriminant the check
-- needs to be made against the level of the object denoted by
-- the prefix of the selected name (Accessibility_Level handles
-- checking the prefix of the operand for this case).
if Nkind (Operand) = N_Selected_Component
and then Static_Accessibility_Level
(Operand, Zero_On_Dynamic_Level)
> Deepest_Type_Access_Level (Target_Type)
then
-- In an instance, this is a run-time check, but one we know
-- will fail, so generate an appropriate warning. The raise
-- will be generated by Expand_N_Type_Conversion.
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Conversion_Error_N
("cannot convert access discriminant to non-local "
& "access type<<", Operand);
Conversion_Error_N ("\Program_Error [<<", Operand);
-- Real error if not in instance body
else
Conversion_Error_N
("cannot convert access discriminant to non-local "
& "access type", Operand);
return False;
end if;
end if;
-- The case of a reference to an access discriminant from
-- within a limited type declaration (which will appear as
-- a discriminal) is always illegal because the level of the
-- discriminant is considered to be deeper than any (nameable)
-- access type.
if Is_Entity_Name (Operand)
and then not Is_Local_Anonymous_Access (Opnd_Type)
and then
Ekind (Entity (Operand)) in E_In_Parameter | E_Constant
and then Present (Discriminal_Link (Entity (Operand)))
then
Conversion_Error_N
("discriminant has deeper accessibility level than target",
Operand);
return False;
end if;
end if;
end if;
return True;
-- General and anonymous access types
elsif Ekind (Target_Type) in
E_General_Access_Type | E_Anonymous_Access_Type
and then
Conversion_Check
(Is_Access_Type (Opnd_Type)
and then
Ekind (Opnd_Type) not in
E_Access_Subprogram_Type |
E_Access_Protected_Subprogram_Type,
"must be an access-to-object type")
then
if Is_Access_Constant (Opnd_Type)
and then not Is_Access_Constant (Target_Type)
then
Conversion_Error_N
("access-to-constant operand type not allowed", Operand);
return False;
end if;
-- Check the static accessibility rule of 4.6(17). Note that the
-- check is not enforced when within an instance body, since the RM
-- requires such cases to be caught at run time.
if Ekind (Target_Type) /= E_Anonymous_Access_Type
or else Is_Local_Anonymous_Access (Target_Type)
or else Nkind (Associated_Node_For_Itype (Target_Type)) =
N_Object_Declaration
then
-- Ada 2012 (AI05-0149): Perform legality checking on implicit
-- conversions from an anonymous access type to a named general
-- access type. Such conversions are not allowed in the case of
-- access parameters and stand-alone objects of an anonymous
-- access type. The implicit conversion case is recognized by
-- testing that Comes_From_Source is False and that it's been
-- rewritten. The Comes_From_Source test isn't sufficient because
-- nodes in inlined calls to predefined library routines can have
-- Comes_From_Source set to False. (Is there a better way to test
-- for implicit conversions???).
--
-- Do not treat a rewritten 'Old attribute reference like other
-- rewrite substitutions. This makes a difference, for example,
-- in the case where we are generating the expansion of a
-- membership test of the form
-- Saooaaat'Old in Named_Access_Type
-- because in this case Valid_Conversion needs to return True
-- (otherwise the expansion will be False - see the call site
-- in exp_ch4.adb).
if Ada_Version >= Ada_2012
and then not Comes_From_Source (N)
and then Is_Rewrite_Substitution (N)
and then not Is_Attribute_Old (Original_Node (N))
and then Ekind (Base_Type (Target_Type)) = E_General_Access_Type
and then Ekind (Opnd_Type) = E_Anonymous_Access_Type
then
if Is_Itype (Opnd_Type) then
-- Implicit conversions aren't allowed for objects of an
-- anonymous access type, since such objects have nonstatic
-- levels in Ada 2012.
if Nkind (Associated_Node_For_Itype (Opnd_Type)) =
N_Object_Declaration
then
Conversion_Error_N
("implicit conversion of stand-alone anonymous "
& "access object not allowed", Operand);
return False;
-- Implicit conversions aren't allowed for anonymous access
-- parameters. We exclude anonymous access results as well
-- as universal_access "=".
elsif not Is_Local_Anonymous_Access (Opnd_Type)
and then Nkind (Associated_Node_For_Itype (Opnd_Type)) in
N_Function_Specification |
N_Procedure_Specification
and then Nkind (Parent (N)) not in N_Op_Eq | N_Op_Ne
then
Conversion_Error_N
("implicit conversion of anonymous access parameter "
& "not allowed", Operand);
return False;
-- Detect access discriminant values that are illegal
-- implicit anonymous-to-named access conversion operands.
elsif Is_Discrim_Of_Bad_Access_Conversion_Argument (Operand)
then
Conversion_Error_N
("implicit conversion of anonymous access value "
& "not allowed", Operand);
return False;
-- In other cases, the level of the operand's type must be
-- statically less deep than that of the target type, else
-- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
elsif Type_Access_Level (Opnd_Type) >
Deepest_Type_Access_Level (Target_Type)
then
Conversion_Error_N
("implicit conversion of anonymous access value "
& "violates accessibility", Operand);
return False;
end if;
end if;
-- Check if the operand is deeper than the target type, taking
-- care to avoid the case where we are converting a result of a
-- function returning an anonymous access type since the "master
-- of the call" would be target type of the conversion unless
-- the target type is anonymous access as well - see RM 3.10.2
-- (10.3/3).
elsif Type_Access_Level (Opnd_Type) >
Deepest_Type_Access_Level (Target_Type)
and then (Nkind (Associated_Node_For_Itype (Opnd_Type)) /=
N_Function_Specification
or else Ekind (Target_Type) in
Anonymous_Access_Kind)
-- Check we are not in a return value ???
and then (not In_Return_Value (N)
or else
Nkind (Associated_Node_For_Itype (Target_Type))
= N_Component_Declaration)
then
-- In an instance, this is a run-time check, but one we know
-- will fail, so generate an appropriate warning. The raise
-- will be generated by Expand_N_Type_Conversion.
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Conversion_Error_N
("cannot convert local pointer to non-local access type<<",
Operand);
Conversion_Error_N ("\Program_Error [<<", Operand);
-- If not in an instance body, this is a real error
else
-- Avoid generation of spurious error message
if not Error_Posted (N) then
Conversion_Error_N
("cannot convert local pointer to non-local access type",
Operand);
end if;
return False;
end if;
-- Special accessibility checks are needed in the case of access
-- discriminants declared for a limited type.
elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type
and then not Is_Local_Anonymous_Access (Opnd_Type)
then
-- When the operand is a selected access discriminant the check
-- needs to be made against the level of the object denoted by
-- the prefix of the selected name (Accessibility_Level handles
-- checking the prefix of the operand for this case).
if Nkind (Operand) = N_Selected_Component
and then Static_Accessibility_Level
(Operand, Zero_On_Dynamic_Level)
> Deepest_Type_Access_Level (Target_Type)
then
-- In an instance, this is a run-time check, but one we know
-- will fail, so generate an appropriate warning. The raise
-- will be generated by Expand_N_Type_Conversion.
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Conversion_Error_N
("cannot convert access discriminant to non-local "
& "access type<<", Operand);
Conversion_Error_N ("\Program_Error [<<", Operand);
-- If not in an instance body, this is a real error
else
Conversion_Error_N
("cannot convert access discriminant to non-local "
& "access type", Operand);
return False;
end if;
end if;
-- The case of a reference to an access discriminant from
-- within a limited type declaration (which will appear as
-- a discriminal) is always illegal because the level of the
-- discriminant is considered to be deeper than any (nameable)
-- access type.
if Is_Entity_Name (Operand)
and then
Ekind (Entity (Operand)) in E_In_Parameter | E_Constant
and then Present (Discriminal_Link (Entity (Operand)))
then
Conversion_Error_N
("discriminant has deeper accessibility level than target",
Operand);
return False;
end if;
end if;
end if;
-- In the presence of limited_with clauses we have to use nonlimited
-- views, if available.
Check_Limited : declare
function Full_Designated_Type (T : Entity_Id) return Entity_Id;
-- Helper function to handle limited views
--------------------------
-- Full_Designated_Type --
--------------------------
function Full_Designated_Type (T : Entity_Id) return Entity_Id is
Desig : constant Entity_Id := Designated_Type (T);
begin
-- Handle the limited view of a type
if From_Limited_With (Desig)
and then Has_Non_Limited_View (Desig)
then
return Available_View (Desig);
else
return Desig;
end if;
end Full_Designated_Type;
-- Local Declarations
Target : constant Entity_Id := Full_Designated_Type (Target_Type);
Opnd : constant Entity_Id := Full_Designated_Type (Opnd_Type);
Same_Base : constant Boolean :=
Base_Type (Target) = Base_Type (Opnd);
-- Start of processing for Check_Limited
begin
if Is_Tagged_Type (Target) then
return Valid_Tagged_Conversion (Target, Opnd);
else
if not Same_Base then
Conversion_Error_NE
("target designated type not compatible with }",
N, Base_Type (Opnd));
return False;
-- Ada 2005 AI-384: legality rule is symmetric in both
-- designated types. The conversion is legal (with possible
-- constraint check) if either designated type is
-- unconstrained.
elsif Subtypes_Statically_Match (Target, Opnd)
or else
(Has_Discriminants (Target)
and then
(not Is_Constrained (Opnd)
or else not Is_Constrained (Target)))
then
-- Special case, if Value_Size has been used to make the
-- sizes different, the conversion is not allowed even
-- though the subtypes statically match.
if Known_Static_RM_Size (Target)
and then Known_Static_RM_Size (Opnd)
and then RM_Size (Target) /= RM_Size (Opnd)
then
Conversion_Error_NE
("target designated subtype not compatible with }",
N, Opnd);
Conversion_Error_NE
("\because sizes of the two designated subtypes differ",
N, Opnd);
return False;
-- Normal case where conversion is allowed
else
return True;
end if;
else
Error_Msg_NE
("target designated subtype not compatible with }",
N, Opnd);
return False;
end if;
end if;
end Check_Limited;
-- Access to subprogram types. If the operand is an access parameter,
-- the type has a deeper accessibility that any master, and cannot be
-- assigned. We must make an exception if the conversion is part of an
-- assignment and the target is the return object of an extended return
-- statement, because in that case the accessibility check takes place
-- after the return.
elsif Is_Access_Subprogram_Type (Target_Type)
-- Note: this test of Opnd_Type is there to prevent entering this
-- branch in the case of a remote access to subprogram type, which
-- is internally represented as an E_Record_Type.
and then Is_Access_Type (Opnd_Type)
then
if Ekind (Base_Type (Opnd_Type)) = E_Anonymous_Access_Subprogram_Type
and then Is_Entity_Name (Operand)
and then Ekind (Entity (Operand)) = E_In_Parameter
and then
(Nkind (Parent (N)) /= N_Assignment_Statement
or else not Is_Entity_Name (Name (Parent (N)))
or else not Is_Return_Object (Entity (Name (Parent (N)))))
then
Conversion_Error_N
("illegal attempt to store anonymous access to subprogram",
Operand);
Conversion_Error_N
("\value has deeper accessibility than any master "
& "(RM 3.10.2 (13))",
Operand);
Error_Msg_NE
("\use named access type for& instead of access parameter",
Operand, Entity (Operand));
end if;
-- Check that the designated types are subtype conformant
Check_Subtype_Conformant (New_Id => Designated_Type (Target_Type),
Old_Id => Designated_Type (Opnd_Type),
Err_Loc => N);
-- Check the static accessibility rule of 4.6(20)
if Type_Access_Level (Opnd_Type) >
Deepest_Type_Access_Level (Target_Type)
then
Conversion_Error_N
("operand type has deeper accessibility level than target",
Operand);
-- Check that if the operand type is declared in a generic body,
-- then the target type must be declared within that same body
-- (enforces last sentence of 4.6(20)).
elsif Present (Enclosing_Generic_Body (Opnd_Type)) then
declare
O_Gen : constant Node_Id :=
Enclosing_Generic_Body (Opnd_Type);
T_Gen : Node_Id;
begin
T_Gen := Enclosing_Generic_Body (Target_Type);
while Present (T_Gen) and then T_Gen /= O_Gen loop
T_Gen := Enclosing_Generic_Body (T_Gen);
end loop;
if T_Gen /= O_Gen then
Conversion_Error_N
("target type must be declared in same generic body "
& "as operand type", N);
end if;
end;
end if;
return True;
-- Remote access to subprogram types
elsif Is_Remote_Access_To_Subprogram_Type (Target_Type)
and then Is_Remote_Access_To_Subprogram_Type (Opnd_Type)
then
-- It is valid to convert from one RAS type to another provided
-- that their specification statically match.
-- Note: at this point, remote access to subprogram types have been
-- expanded to their E_Record_Type representation, and we need to
-- go back to the original access type definition using the
-- Corresponding_Remote_Type attribute in order to check that the
-- designated profiles match.
pragma Assert (Ekind (Target_Type) = E_Record_Type);
pragma Assert (Ekind (Opnd_Type) = E_Record_Type);
Check_Subtype_Conformant
(New_Id =>
Designated_Type (Corresponding_Remote_Type (Target_Type)),
Old_Id =>
Designated_Type (Corresponding_Remote_Type (Opnd_Type)),
Err_Loc =>
N);
return True;
-- If it was legal in the generic, it's legal in the instance
elsif In_Instance_Body then
return True;
-- If both are tagged types, check legality of view conversions
elsif Is_Tagged_Type (Target_Type)
and then
Is_Tagged_Type (Opnd_Type)
then
return Valid_Tagged_Conversion (Target_Type, Opnd_Type);
-- Types derived from the same root type are convertible
elsif Root_Type (Target_Type) = Root_Type (Opnd_Type) then
return True;
-- In an instance or an inlined body, there may be inconsistent views of
-- the same type, or of types derived from a common root.
elsif (In_Instance or In_Inlined_Body)
and then
Root_Type (Underlying_Type (Target_Type)) =
Root_Type (Underlying_Type (Opnd_Type))
then
return True;
-- Special check for common access type error case
elsif Ekind (Target_Type) = E_Access_Type
and then Is_Access_Type (Opnd_Type)
then
Conversion_Error_N ("target type must be general access type!", N);
Conversion_Error_NE -- CODEFIX
("add ALL to }!", N, Target_Type);
return False;
-- Here we have a real conversion error
else
-- Check for missing regular with_clause when only a limited view of
-- target is available.
if From_Limited_With (Opnd_Type) and then In_Package_Body then
Conversion_Error_NE
("invalid conversion, not compatible with limited view of }",
N, Opnd_Type);
Conversion_Error_NE
("\add with_clause for& to current unit!", N, Scope (Opnd_Type));
elsif Is_Access_Type (Opnd_Type)
and then From_Limited_With (Designated_Type (Opnd_Type))
and then In_Package_Body
then
Conversion_Error_NE
("invalid conversion, not compatible with }", N, Opnd_Type);
Conversion_Error_NE
("\add with_clause for& to current unit!",
N, Scope (Designated_Type (Opnd_Type)));
else
Conversion_Error_NE
("invalid conversion, not compatible with }", N, Opnd_Type);
end if;
return False;
end if;
end Valid_Conversion;
end Sem_Res;
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