gdb: fix darwin-nat.c build / adapt to multi-target

The darwin-nat.c file doesn't build since the multi-target changes
(5b6d1e4f, "Multi-target support").  This patch makes it build.  I have
access to a macOS vm, so I am able to build it, but I wasn't able to
successfully codesign it and try to actually debug something, so I don't
know if it works.  I don't have much more time to put on this to figure
it out, so I thought I'd sent the patch anyway, as it's at least a step
in the right direction.

The bulk of the patch is to change a bunch of functions to be methods of
the darwin_nat_target object, so that this can pass `this` to
find_inferior_ptid and other functions that now require a
process_stratum_target pointer.

The darwin_ptrace_him function (renamed to darwin_nat_target::ptrace_him
in this patch) is passed to fork_inferior as the `init_trace_fun`
parameter.  Since the method can't be passed as a plain function pointer
(we need the `this` pointer), I changed the `init_trace_fun` parameter
of fork_inferior to be a gdb::function_view, so we can pass a lambda and
capture `this`.

The changes in darwin-nat.h are only to move definition higher in the
file, so that forward declarations are not needed.

gdb/ChangeLog:

	* darwin-nat.h (struct darwin_exception_msg, enum
	darwin_msg_state, struct darwin_thread_info, darwin_thread_t):
	Move up.
	(class darwin_nat_target) <wait_1, check_new_threads,
	decode_exception_message, decode_message, stop_inferior,
	init_thread_list, ptrace_him, cancel_breakpoint>: Declare.
	* darwin-nat.c (darwin_check_new_threads): Rename to...
	(darwin_nat_target::check_new_threads): ... this.
	(darwin_suspend_inferior_it): Remove.
	(darwin_decode_exception_message): Rename to...
	(darwin_nat_target::decode_exception_message): ... this.
	(darwin_nat_target::resume): Pass target to find_inferior_ptid.
	(darwin_decode_message): Rename to...
	(darwin_nat_target::decode_message): ... this.
	(cancel_breakpoint): Rename to...
	(darwin_nat_target::cancel_breakpoint): ... this.
	(darwin_wait): Rename to...
	(darwin_nat_target::wait_1): ... this.  Use range-based for loop
	instead of iterate_over_inferiors.
	(darwin_nat_target::wait): Call wait_1 instead of darwin_wait.
	(darwin_stop_inferior): Rename to...
	(darwin_nat_target::stop_inferior): ... this.
	(darwin_nat_target::kill): Call wait_1 instead of darwin_wait.
	(darwin_init_thread_list): Rename to...
	(darwin_nat_target::init_thread_list): ... this.
	(darwin_ptrace_him): Rename to...
	(darwin_nat_target::ptrace_him): ... this.
	(darwin_nat_target::create_inferior): Pass lambda function to
	fork_inferior.
	(darwin_nat_target::detach): Call stop_inferior instead of
	darwin_stop_inferior.
	* fork-inferior.h (fork_inferior): Change init_trace_fun
	parameter to gdb::function_view.
	* fork-inferior.c (fork_inferior): Likewise.

gdb/ChangeLog

@@ -1,3 +1,40 @@
+2020-01-23  Simon Marchi  <simon.marchi@efficios.com>
+
+	* darwin-nat.h (struct darwin_exception_msg, enum
+	darwin_msg_state, struct darwin_thread_info, darwin_thread_t):
+	Move up.
+	(class darwin_nat_target) <wait_1, check_new_threads,
+	decode_exception_message, decode_message, stop_inferior,
+	init_thread_list, ptrace_him, cancel_breakpoint>: Declare.
+	* darwin-nat.c (darwin_check_new_threads): Rename to...
+	(darwin_nat_target::check_new_threads): ... this.
+	(darwin_suspend_inferior_it): Remove.
+	(darwin_decode_exception_message): Rename to...
+	(darwin_nat_target::decode_exception_message): ... this.
+	(darwin_nat_target::resume): Pass target to find_inferior_ptid.
+	(darwin_decode_message): Rename to...
+	(darwin_nat_target::decode_message): ... this.
+	(cancel_breakpoint): Rename to...
+	(darwin_nat_target::cancel_breakpoint): ... this.
+	(darwin_wait): Rename to...
+	(darwin_nat_target::wait_1): ... this.  Use range-based for loop
+	instead of iterate_over_inferiors.
+	(darwin_nat_target::wait): Call wait_1 instead of darwin_wait.
+	(darwin_stop_inferior): Rename to...
+	(darwin_nat_target::stop_inferior): ... this.
+	(darwin_nat_target::kill): Call wait_1 instead of darwin_wait.
+	(darwin_init_thread_list): Rename to...
+	(darwin_nat_target::init_thread_list): ... this.
+	(darwin_ptrace_him): Rename to...
+	(darwin_nat_target::ptrace_him): ... this.
+	(darwin_nat_target::create_inferior): Pass lambda function to
+	fork_inferior.
+	(darwin_nat_target::detach): Call stop_inferior instead of
+	darwin_stop_inferior.
+	* fork-inferior.h (fork_inferior): Change init_trace_fun
+	parameter to gdb::function_view.
+	* fork-inferior.c (fork_inferior): Likewise.
+
 2020-01-23  Hannes Domani  <ssbssa@yahoo.de>
 
 	* i386-cygwin-tdep.c (core_process_module_section): Update.

gdb/darwin-nat.c

@@ -89,12 +89,8 @@
 #define PTRACE(CMD, PID, ADDR, SIG) \
  darwin_ptrace(#CMD, CMD, (PID), (ADDR), (SIG))
 
-static ptid_t darwin_wait (ptid_t ptid, struct target_waitstatus *status);
-
 static void darwin_ptrace_me (void);
 
-static void darwin_ptrace_him (int pid);
-
 static void darwin_encode_reply (mig_reply_error_t *reply,
 				 mach_msg_header_t *hdr, integer_t code);
 
@@ -258,8 +254,8 @@ cmp_thread_t (const void *l, const void *r)
   return (int)(tl - tr);
 }
 
-static void
+void
-darwin_check_new_threads (struct inferior *inf)
+darwin_nat_target::check_new_threads (inferior *inf)
 {
   kern_return_t kret;
   thread_array_t thread_list;
@@ -355,7 +351,7 @@ darwin_check_new_threads (struct inferior *inf)
 	  pti->msg_state = DARWIN_RUNNING;
 
 	  /* Add the new thread.  */
-	  add_thread_with_info (ptid_t (inf->pid, 0, new_id), pti);
+	  add_thread_with_info (this, ptid_t (inf->pid, 0, new_id), pti);
 	  new_thread_vec.push_back (pti);
 	  new_ix++;
 	  continue;
@@ -364,7 +360,7 @@ darwin_check_new_threads (struct inferior *inf)
 	{
 	  /* A thread was removed.  */
 	  struct thread_info *thr
-	    = find_thread_ptid (ptid_t (inf->pid, 0, old_id));
+	    = find_thread_ptid (this, ptid_t (inf->pid, 0, old_id));
 	  delete_thread (thr);
 	  kret = mach_port_deallocate (gdb_task, old_id);
 	  MACH_CHECK_ERROR (kret);
@@ -464,14 +460,6 @@ darwin_resume_inferior (struct inferior *inf)
 
 /* Iterator functions.  */
 
-static int
-darwin_suspend_inferior_it (struct inferior *inf, void *arg)
-{
-  darwin_suspend_inferior (inf);
-  darwin_check_new_threads (inf);
-  return 0;
-}
-
 static int
 darwin_resume_inferior_it (struct inferior *inf, void *arg)
 {
@@ -611,9 +599,9 @@ darwin_check_message_ndr (NDR_record_t *ndr)
 
 /* Decode an exception message.  */
 
-static int
+int
-darwin_decode_exception_message (mach_msg_header_t *hdr,
+darwin_nat_target::decode_exception_message (mach_msg_header_t *hdr,
-				 struct inferior **pinf,
+					     inferior **pinf,
 					     darwin_thread_t **pthread)
 {
   mach_msg_body_t *bod = (mach_msg_body_t*)(hdr + 1);
@@ -712,7 +700,7 @@ darwin_decode_exception_message (mach_msg_header_t *hdr,
   /* Find thread by port.  */
   /* Check for new threads.  Do it early so that the port in the exception
      message can be deallocated.  */
-  darwin_check_new_threads (inf);
+  check_new_threads (inf);
 
   /* Free the thread port (as gdb knows the thread, it has already has a right
      for it, so this just decrement a reference counter).  */
@@ -975,7 +963,7 @@ darwin_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signal)
     }
   else
     {
-      struct inferior *inf = find_inferior_ptid (ptid);
+      inferior *inf = find_inferior_ptid (this, ptid);
       long tid = ptid.tid ();
 
       /* Stop the inferior (should be useless).  */
@@ -1001,11 +989,11 @@ darwin_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signal)
     }
 }
 
-static ptid_t
+ptid_t
-darwin_decode_message (mach_msg_header_t *hdr,
+darwin_nat_target::decode_message (mach_msg_header_t *hdr,
 				   darwin_thread_t **pthread,
-		       struct inferior **pinf,
+				   inferior **pinf,
-		       struct target_waitstatus *status)
+				   target_waitstatus *status)
 {
   darwin_thread_t *thread;
   struct inferior *inf;
@@ -1016,7 +1004,7 @@ darwin_decode_message (mach_msg_header_t *hdr,
       int res;
 
       /* Decode message.  */
-      res = darwin_decode_exception_message (hdr, &inf, &thread);
+      res = decode_exception_message (hdr, &inf, &thread);
 
       if (res < 0)
 	{
@@ -1172,8 +1160,8 @@ darwin_decode_message (mach_msg_header_t *hdr,
   return minus_one_ptid;
 }
 
-static int
+int
-cancel_breakpoint (ptid_t ptid)
+darwin_nat_target::cancel_breakpoint (ptid_t ptid)
 {
   /* Arrange for a breakpoint to be hit again later.  We will handle
      the current event, eventually we will resume this thread, and this
@@ -1183,7 +1171,7 @@ cancel_breakpoint (ptid_t ptid)
      delete or disable the breakpoint, but the thread will have already
      tripped on it.  */
 
-  struct regcache *regcache = get_thread_regcache (ptid);
+  struct regcache *regcache = get_thread_regcache (this, ptid);
   struct gdbarch *gdbarch = regcache->arch ();
   CORE_ADDR pc;
 
@@ -1202,8 +1190,8 @@ cancel_breakpoint (ptid_t ptid)
   return 0;
 }
 
-static ptid_t
+ptid_t
-darwin_wait (ptid_t ptid, struct target_waitstatus *status)
+darwin_nat_target::wait_1 (ptid_t ptid, struct target_waitstatus *status)
 {
   kern_return_t kret;
   union
@@ -1262,7 +1250,7 @@ darwin_wait (ptid_t ptid, struct target_waitstatus *status)
       if (darwin_debug_flag > 10)
 	darwin_dump_message (hdr, darwin_debug_flag > 11);
 
-      res = darwin_decode_message (hdr, &thread, &inf, status);
+      res = decode_message (hdr, &thread, &inf, status);
       if (res == minus_one_ptid)
 	continue;
 
@@ -1273,7 +1261,11 @@ darwin_wait (ptid_t ptid, struct target_waitstatus *status)
   while (status->kind == TARGET_WAITKIND_IGNORE);
 
   /* Stop all tasks.  */
-  iterate_over_inferiors (darwin_suspend_inferior_it, NULL);
+  for (inferior *inf : all_inferiors (this))
+    {
+      darwin_suspend_inferior (inf);
+      check_new_threads (inf);
+    }
 
   /* Read pending messages.  */
   while (1)
@@ -1298,7 +1290,7 @@ darwin_wait (ptid_t ptid, struct target_waitstatus *status)
       if (darwin_debug_flag > 10)
 	darwin_dump_message (hdr, darwin_debug_flag > 11);
 
-      ptid2 = darwin_decode_message (hdr, &thread, &inf, &status2);
+      ptid2 = decode_message (hdr, &thread, &inf, &status2);
 
       if (inf != NULL && thread != NULL
 	  && thread->event.ex_type == EXC_BREAKPOINT)
@@ -1325,7 +1317,7 @@ ptid_t
 darwin_nat_target::wait (ptid_t ptid, struct target_waitstatus *status,
 			 int options)
 {
-  return darwin_wait (ptid, status);
+  return wait_1 (ptid, status);
 }
 
 void
@@ -1415,8 +1407,8 @@ darwin_reply_to_all_pending_messages (struct inferior *inf)
     }
 }
 
-static void
+void
-darwin_stop_inferior (struct inferior *inf)
+darwin_nat_target::stop_inferior (inferior *inf)
 {
   struct target_waitstatus wstatus;
   ptid_t ptid;
@@ -1432,14 +1424,14 @@ darwin_stop_inferior (struct inferior *inf)
   if (priv->no_ptrace)
     return;
 
-  res = kill (inf->pid, SIGSTOP);
+  res = ::kill (inf->pid, SIGSTOP);
   if (res != 0)
     warning (_("cannot kill: %s"), safe_strerror (errno));
 
   /* Wait until the process is really stopped.  */
   while (1)
     {
-      ptid = darwin_wait (inferior_ptid, &wstatus);
+      ptid = wait_1 (inferior_ptid, &wstatus);
       if (wstatus.kind == TARGET_WAITKIND_STOPPED
 	  && wstatus.value.sig == GDB_SIGNAL_STOP)
 	break;
@@ -1564,7 +1556,7 @@ darwin_nat_target::kill ()
 
       darwin_resume_inferior (inf);
 
-      ptid = darwin_wait (inferior_ptid, &wstatus);
+      ptid = wait_1 (inferior_ptid, &wstatus);
     }
   else if (errno != ESRCH)
     warning (_("Failed to kill inferior: kill (%d, 9) returned [%s]"),
@@ -1716,10 +1708,10 @@ thread_info_from_private_thread_info (darwin_thread_info *pti)
   gdb_assert_not_reached ("did not find gdb thread for darwin thread");
 }
 
-static void
+void
-darwin_init_thread_list (struct inferior *inf)
+darwin_nat_target::init_thread_list (inferior *inf)
 {
-  darwin_check_new_threads (inf);
+  check_new_threads (inf);
 
   darwin_inferior *priv = get_darwin_inferior (inf);
 
@@ -1783,21 +1775,21 @@ darwin_pre_ptrace (void)
   mark_fd_no_cloexec (ptrace_fds[1]);
 }
 
-static void
+void
-darwin_ptrace_him (int pid)
+darwin_nat_target::ptrace_him (int pid)
 {
   struct inferior *inf = current_inferior ();
 
   darwin_attach_pid (inf);
 
   /* Let's the child run.  */
-  close (ptrace_fds[0]);
+  ::close (ptrace_fds[0]);
-  close (ptrace_fds[1]);
+  ::close (ptrace_fds[1]);
 
   unmark_fd_no_cloexec (ptrace_fds[0]);
   unmark_fd_no_cloexec (ptrace_fds[1]);
 
-  darwin_init_thread_list (inf);
+  init_thread_list (inf);
 
   gdb_startup_inferior (pid, START_INFERIOR_TRAPS_EXPECTED);
 }
@@ -1986,6 +1978,7 @@ darwin_nat_target::create_inferior (const char *exec_file,
 				    char **env, int from_tty)
 {
   gdb::optional<scoped_restore_tmpl<bool>> restore_startup_with_shell;
+  darwin_nat_target *the_target = this;
 
   if (startup_with_shell && may_have_sip ())
     {
@@ -1998,7 +1991,11 @@ darwin_nat_target::create_inferior (const char *exec_file,
 
   /* Do the hard work.  */
   fork_inferior (exec_file, allargs, env, darwin_ptrace_me,
-		 darwin_ptrace_him, darwin_pre_ptrace, copied_shell,
+		 [the_target] (int pid)
+		   {
+		     the_target->ptrace_him (pid);
+		   },
+		 darwin_pre_ptrace, copied_shell,
 		 darwin_execvp);
 }
 
@@ -2068,7 +2065,7 @@ darwin_nat_target::attach (const char *args, int from_tty)
 
   darwin_suspend_inferior (inf);
 
-  darwin_init_thread_list (inf);
+  init_thread_list (inf);
 
   darwin_inferior *priv = get_darwin_inferior (inf);
 
@@ -2099,7 +2096,7 @@ darwin_nat_target::detach (inferior *inf, int from_tty)
 
   /* If ptrace() is in use, stop the process.  */
   if (!priv->no_ptrace)
-    darwin_stop_inferior (inf);
+    stop_inferior (inf);
 
   kret = darwin_restore_exception_ports (priv);
   MACH_CHECK_ERROR (kret);

gdb/darwin-nat.h

@@ -21,68 +21,6 @@
 #include <mach/mach.h>
 #include "gdbthread.h"
 
-/* This needs to be overridden by the platform specific nat code.  */
-
-class darwin_nat_target : public inf_child_target
-{
-  void create_inferior (const char *exec_file,
-			const std::string &allargs,
-			char **env, int from_tty) override;
-
-  void attach (const char *, int) override;
-
-  void detach (inferior *, int) override;
-
-  ptid_t wait (ptid_t, struct target_waitstatus *, int) override;
-
-  void mourn_inferior () override;
-
-  void kill () override;
-
-  void interrupt () override;
-
-  void resume (ptid_t, int , enum gdb_signal) override;
-
-  bool thread_alive (ptid_t ptid) override;
-
-  std::string pid_to_str (ptid_t) override;
-
-  char *pid_to_exec_file (int pid) override;
-
-  enum target_xfer_status xfer_partial (enum target_object object,
-					const char *annex,
-					gdb_byte *readbuf,
-					const gdb_byte *writebuf,
-					ULONGEST offset, ULONGEST len,
-					ULONGEST *xfered_len) override;
-
-  bool supports_multi_process () override;
-
-  ptid_t get_ada_task_ptid (long lwp, long thread) override;
-};
-
-/* Describe the mach exception handling state for a task.  This state is saved
-   before being changed and restored when a process is detached.
-   For more information on these fields see task_get_exception_ports manual
-   page.  */
-struct darwin_exception_info
-{
-  /* Exceptions handled by the port.  */
-  exception_mask_t masks[EXC_TYPES_COUNT] {};
-
-  /* Ports receiving exception messages.  */
-  mach_port_t ports[EXC_TYPES_COUNT] {};
-
-  /* Type of messages sent.  */
-  exception_behavior_t behaviors[EXC_TYPES_COUNT] {};
-
-  /* Type of state to be sent.  */
-  thread_state_flavor_t flavors[EXC_TYPES_COUNT] {};
-
-  /* Number of elements set.  */
-  mach_msg_type_number_t count = 0;
-};
-
 struct darwin_exception_msg
 {
   mach_msg_header_t header;
@@ -136,6 +74,83 @@ struct darwin_thread_info : public private_thread_info
 };
 typedef struct darwin_thread_info darwin_thread_t;
 
+/* This needs to be overridden by the platform specific nat code.  */
+
+class darwin_nat_target : public inf_child_target
+{
+  void create_inferior (const char *exec_file,
+			const std::string &allargs,
+			char **env, int from_tty) override;
+
+  void attach (const char *, int) override;
+
+  void detach (inferior *, int) override;
+
+  ptid_t wait (ptid_t, struct target_waitstatus *, int) override;
+
+  void mourn_inferior () override;
+
+  void kill () override;
+
+  void interrupt () override;
+
+  void resume (ptid_t, int , enum gdb_signal) override;
+
+  bool thread_alive (ptid_t ptid) override;
+
+  std::string pid_to_str (ptid_t) override;
+
+  char *pid_to_exec_file (int pid) override;
+
+  enum target_xfer_status xfer_partial (enum target_object object,
+					const char *annex,
+					gdb_byte *readbuf,
+					const gdb_byte *writebuf,
+					ULONGEST offset, ULONGEST len,
+					ULONGEST *xfered_len) override;
+
+  bool supports_multi_process () override;
+
+  ptid_t get_ada_task_ptid (long lwp, long thread) override;
+
+private:
+  ptid_t wait_1 (ptid_t, struct target_waitstatus *);
+  void check_new_threads (inferior *inf);
+  int decode_exception_message (mach_msg_header_t *hdr,
+			        inferior **pinf,
+				darwin_thread_t **pthread);
+  ptid_t decode_message (mach_msg_header_t *hdr,
+			 darwin_thread_t **pthread,
+			 inferior **pinf,
+			 target_waitstatus *status);
+  void stop_inferior (inferior *inf);
+  void init_thread_list (inferior *inf);
+  void ptrace_him (int pid);
+  int cancel_breakpoint (ptid_t ptid);
+};
+
+/* Describe the mach exception handling state for a task.  This state is saved
+   before being changed and restored when a process is detached.
+   For more information on these fields see task_get_exception_ports manual
+   page.  */
+struct darwin_exception_info
+{
+  /* Exceptions handled by the port.  */
+  exception_mask_t masks[EXC_TYPES_COUNT] {};
+
+  /* Ports receiving exception messages.  */
+  mach_port_t ports[EXC_TYPES_COUNT] {};
+
+  /* Type of messages sent.  */
+  exception_behavior_t behaviors[EXC_TYPES_COUNT] {};
+
+  /* Type of state to be sent.  */
+  thread_state_flavor_t flavors[EXC_TYPES_COUNT] {};
+
+  /* Number of elements set.  */
+  mach_msg_type_number_t count = 0;
+};
+
 static inline darwin_thread_info *
 get_darwin_thread_info (class thread_info *thread)
 {

gdb/nat/fork-inferior.c

@@ -267,7 +267,8 @@ execv_argv::init_for_shell (const char *exec_file,
 pid_t
 fork_inferior (const char *exec_file_arg, const std::string &allargs,
 	       char **env, void (*traceme_fun) (),
-	       void (*init_trace_fun) (int), void (*pre_trace_fun) (),
+	       gdb::function_view<void (int)> init_trace_fun,
+	       void (*pre_trace_fun) (),
 	       const char *shell_file_arg,
                void (*exec_fun)(const char *file, char * const *argv,
                                 char * const *env))
@@ -439,7 +440,7 @@ fork_inferior (const char *exec_file_arg, const std::string &allargs,
      initialize anything target-vector-specific that needs
      initializing.  */
   if (init_trace_fun)
-    (*init_trace_fun) (pid);
+    init_trace_fun (pid);
 
   /* We are now in the child process of interest, having exec'd the
      correct program, and are poised at the first instruction of the

gdb/nat/fork-inferior.h

@@ -21,6 +21,7 @@
 #define NAT_FORK_INFERIOR_H
 
 #include <string>
+#include "gdbsupport/function-view.h"
 
 struct process_stratum_target;
 
@@ -42,7 +43,7 @@ struct process_stratum_target;
 extern pid_t fork_inferior (const char *exec_file_arg,
 			    const std::string &allargs,
 			    char **env, void (*traceme_fun) (),
-			    void (*init_trace_fun) (int),
+			    gdb::function_view<void (int)> init_trace_fun,
 			    void (*pre_trace_fun) (),
 			    const char *shell_file_arg,
 			    void (*exec_fun) (const char *file,