libgo: update to Go1.16beta1 release

This does not yet include support for the //go:embed directive added
in this release.

	* Makefile.am (check-runtime): Don't create check-runtime-dir.
	(mostlyclean-local): Don't remove check-runtime-dir.
	(check-go-tool, check-vet): Copy in go.mod and modules.txt.
	(check-cgo-test, check-carchive-test): Add go.mod file.
	* Makefile.in: Regenerate.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/280172

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-d67579759e1769c08148304b2d378ec0b05637d6
+47bdc8bb36f16f9d1dec72df5dd6b45d7b0b0725
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gotools/Makefile.am

@@ -101,7 +101,7 @@ MOSTLYCLEANFILES = \
 
 mostlyclean-local:
 	if test -d check-go-dir; then chmod -R u+w check-go-dir; fi
-	rm -rf check-go-dir check-runtime-dir cgo-test-dir carchive-test-dir \
+	rm -rf check-go-dir cgo-test-dir carchive-test-dir \
 	check-vet-dir gocache-test
 
 if NATIVE
@@ -210,6 +210,11 @@ check-go-tool: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 	if test -d check-go-dir; then chmod -R u+w check-go-dir; fi
 	rm -rf check-go-dir cmd_go-testlog
 	$(MKDIR_P) check-go-dir/src/cmd/go
+	cp $(libgosrcdir)/go.mod check-go-dir/src/
+	cp $(cmdsrcdir)/go.mod check-go-dir/src/cmd/
+	$(MKDIR_P) check-go-dir/src/vendor check-go-dir/src/cmd/vendor
+	cp $(libgosrcdir)/vendor/modules.txt check-go-dir/src/vendor/
+	cp $(libgosrcdir)/cmd/vendor/modules.txt check-go-dir/src/cmd/vendor/
 	cp $(cmdsrcdir)/go/*.go check-go-dir/src/cmd/go/
 	cp -r $(cmdsrcdir)/go/internal check-go-dir/src/cmd/go/
 	cp $(libgodir)/zdefaultcc.go check-go-dir/src/cmd/go/internal/cfg/
@@ -234,8 +239,7 @@ check-go-tool: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 # but the runtime tests use the go tool heavily, so testing
 # here too will catch more problems.
 check-runtime: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
-	rm -rf check-runtime-dir runtime-testlog
+	rm -f runtime-testlog
-	$(MKDIR_P) check-runtime-dir
 	@abs_libgodir=`cd $(libgodir) && $(PWD_COMMAND)`; \
 	LD_LIBRARY_PATH=`echo $${abs_libgodir}/.libs:$${LD_LIBRARY_PATH} | sed 's,::*,:,g;s,^:*,,;s,:*$$,,'`; \
 	export LD_LIBRARY_PATH; \
@@ -256,6 +260,7 @@ check-runtime: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 check-cgo-test: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 	rm -rf cgo-test-dir cgo-testlog
 	$(MKDIR_P) cgo-test-dir/misc/cgo
+	echo 'module misc' > cgo-test-dir/misc/go.mod
 	cp -r $(libgomiscdir)/cgo/test cgo-test-dir/misc/cgo/
 	@abs_libgodir=`cd $(libgodir) && $(PWD_COMMAND)`; \
 	echo "cd cgo-test-dir/misc/cgo/test && $(ECHO_ENV) GOTRACEBACK=2 $(abs_builddir)/go$(EXEEXT) test -test.short -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v" > cgo-testlog
@@ -270,6 +275,7 @@ check-cgo-test: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 check-carchive-test: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 	rm -rf carchive-test-dir carchive-testlog
 	$(MKDIR_P) carchive-test-dir/misc/cgo
+	echo 'module misc' > carchive-test-dir/misc/go.mod
 	cp -r $(libgomiscdir)/cgo/testcarchive carchive-test-dir/misc/cgo/
 	@abs_libgodir=`cd $(libgodir) && $(PWD_COMMAND)`; \
 	echo "cd carchive-test-dir/misc/cgo/testcarchive && $(ECHO_ENV) LIBRARY_PATH=`echo $${abs_libgodir}/.libs` $(abs_builddir)/go$(EXEEXT) test -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v" > carchive-testlog
@@ -283,6 +289,11 @@ check-carchive-test: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check
 check-vet: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 	rm -rf check-vet-dir cmd_vet-testlog
 	$(MKDIR_P) check-vet-dir/src/cmd/internal check-vet-dir/src/cmd/vendor/golang.org/x
+	cp $(libgosrcdir)/go.mod check-vet-dir/src/
+	cp $(cmdsrcdir)/go.mod check-vet-dir/src/cmd/
+	$(MKDIR_P) check-vet-dir/src/vendor check-vet-dir/src/cmd/vendor
+	cp $(libgosrcdir)/vendor/modules.txt check-vet-dir/src/vendor/
+	cp $(libgosrcdir)/cmd/vendor/modules.txt check-vet-dir/src/cmd/vendor/
 	cp -r $(cmdsrcdir)/vet check-vet-dir/src/cmd/
 	cp -r $(cmdsrcdir)/internal/objabi check-vet-dir/src/cmd/internal
 	cp $(libgodir)/objabi.go check-vet-dir/src/cmd/internal/objabi/

gotools/Makefile.in

@@ -703,8 +703,8 @@ distclean-generic:
 maintainer-clean-generic:
 	@echo "This command is intended for maintainers to use"
 	@echo "it deletes files that may require special tools to rebuild."
-@NATIVE_FALSE@uninstall-local:
 @NATIVE_FALSE@install-exec-local:
+@NATIVE_FALSE@uninstall-local:
 clean: clean-am
 
 clean-am: clean-binPROGRAMS clean-generic clean-noinstPROGRAMS \
@@ -814,7 +814,7 @@ s-zdefaultcc: Makefile
 
 mostlyclean-local:
 	if test -d check-go-dir; then chmod -R u+w check-go-dir; fi
-	rm -rf check-go-dir check-runtime-dir cgo-test-dir carchive-test-dir \
+	rm -rf check-go-dir cgo-test-dir carchive-test-dir \
 	check-vet-dir gocache-test
 
 @NATIVE_TRUE@go$(EXEEXT): $(go_cmd_go_files) $(LIBGOTOOL) $(LIBGODEP)
@@ -881,6 +881,11 @@ mostlyclean-local:
 @NATIVE_TRUE@	if test -d check-go-dir; then chmod -R u+w check-go-dir; fi
 @NATIVE_TRUE@	rm -rf check-go-dir cmd_go-testlog
 @NATIVE_TRUE@	$(MKDIR_P) check-go-dir/src/cmd/go
+@NATIVE_TRUE@	cp $(libgosrcdir)/go.mod check-go-dir/src/
+@NATIVE_TRUE@	cp $(cmdsrcdir)/go.mod check-go-dir/src/cmd/
+@NATIVE_TRUE@	$(MKDIR_P) check-go-dir/src/vendor check-go-dir/src/cmd/vendor
+@NATIVE_TRUE@	cp $(libgosrcdir)/vendor/modules.txt check-go-dir/src/vendor/
+@NATIVE_TRUE@	cp $(libgosrcdir)/cmd/vendor/modules.txt check-go-dir/src/cmd/vendor/
 @NATIVE_TRUE@	cp $(cmdsrcdir)/go/*.go check-go-dir/src/cmd/go/
 @NATIVE_TRUE@	cp -r $(cmdsrcdir)/go/internal check-go-dir/src/cmd/go/
 @NATIVE_TRUE@	cp $(libgodir)/zdefaultcc.go check-go-dir/src/cmd/go/internal/cfg/
@@ -905,8 +910,7 @@ mostlyclean-local:
 # but the runtime tests use the go tool heavily, so testing
 # here too will catch more problems.
 @NATIVE_TRUE@check-runtime: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
-@NATIVE_TRUE@	rm -rf check-runtime-dir runtime-testlog
+@NATIVE_TRUE@	rm -f runtime-testlog
-@NATIVE_TRUE@	$(MKDIR_P) check-runtime-dir
 @NATIVE_TRUE@	@abs_libgodir=`cd $(libgodir) && $(PWD_COMMAND)`; \
 @NATIVE_TRUE@	LD_LIBRARY_PATH=`echo $${abs_libgodir}/.libs:$${LD_LIBRARY_PATH} | sed 's,::*,:,g;s,^:*,,;s,:*$$,,'`; \
 @NATIVE_TRUE@	export LD_LIBRARY_PATH; \
@@ -927,6 +931,7 @@ mostlyclean-local:
 @NATIVE_TRUE@check-cgo-test: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 @NATIVE_TRUE@	rm -rf cgo-test-dir cgo-testlog
 @NATIVE_TRUE@	$(MKDIR_P) cgo-test-dir/misc/cgo
+@NATIVE_TRUE@	echo 'module misc' > cgo-test-dir/misc/go.mod
 @NATIVE_TRUE@	cp -r $(libgomiscdir)/cgo/test cgo-test-dir/misc/cgo/
 @NATIVE_TRUE@	@abs_libgodir=`cd $(libgodir) && $(PWD_COMMAND)`; \
 @NATIVE_TRUE@	echo "cd cgo-test-dir/misc/cgo/test && $(ECHO_ENV) GOTRACEBACK=2 $(abs_builddir)/go$(EXEEXT) test -test.short -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v" > cgo-testlog
@@ -941,6 +946,7 @@ mostlyclean-local:
 @NATIVE_TRUE@check-carchive-test: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 @NATIVE_TRUE@	rm -rf carchive-test-dir carchive-testlog
 @NATIVE_TRUE@	$(MKDIR_P) carchive-test-dir/misc/cgo
+@NATIVE_TRUE@	echo 'module misc' > carchive-test-dir/misc/go.mod
 @NATIVE_TRUE@	cp -r $(libgomiscdir)/cgo/testcarchive carchive-test-dir/misc/cgo/
 @NATIVE_TRUE@	@abs_libgodir=`cd $(libgodir) && $(PWD_COMMAND)`; \
 @NATIVE_TRUE@	echo "cd carchive-test-dir/misc/cgo/testcarchive && $(ECHO_ENV) LIBRARY_PATH=`echo $${abs_libgodir}/.libs` $(abs_builddir)/go$(EXEEXT) test -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v" > carchive-testlog
@@ -954,6 +960,11 @@ mostlyclean-local:
 @NATIVE_TRUE@check-vet: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 @NATIVE_TRUE@	rm -rf check-vet-dir cmd_vet-testlog
 @NATIVE_TRUE@	$(MKDIR_P) check-vet-dir/src/cmd/internal check-vet-dir/src/cmd/vendor/golang.org/x
+@NATIVE_TRUE@	cp $(libgosrcdir)/go.mod check-vet-dir/src/
+@NATIVE_TRUE@	cp $(cmdsrcdir)/go.mod check-vet-dir/src/cmd/
+@NATIVE_TRUE@	$(MKDIR_P) check-vet-dir/src/vendor check-vet-dir/src/cmd/vendor
+@NATIVE_TRUE@	cp $(libgosrcdir)/vendor/modules.txt check-vet-dir/src/vendor/
+@NATIVE_TRUE@	cp $(libgosrcdir)/cmd/vendor/modules.txt check-vet-dir/src/cmd/vendor/
 @NATIVE_TRUE@	cp -r $(cmdsrcdir)/vet check-vet-dir/src/cmd/
 @NATIVE_TRUE@	cp -r $(cmdsrcdir)/internal/objabi check-vet-dir/src/cmd/internal
 @NATIVE_TRUE@	cp $(libgodir)/objabi.go check-vet-dir/src/cmd/internal/objabi/

libgo/MERGE

@@ -1,4 +1,4 @@
-9b955d2d3fcff6a5bc8bce7bafdc4c634a28e95b
+2ff33f5e443165e55a080f3a649e4c070c4096d1
 
 The first line of this file holds the git revision number of the
 last merge done from the master library sources.

libgo/Makefile.am

@@ -775,6 +775,7 @@ libgo_go_objs = \
 	syscall/errno.lo \
 	syscall/signame.lo \
 	syscall/wait.lo \
+	os/dir_gccgo_c.lo \
 	$(golangorg_x_net_lif_lo) \
 	$(golangorg_x_net_route_lo) \
 	log/syslog/syslog_c.lo \
@@ -1062,6 +1063,7 @@ extra_go_files_os_user = os_user_linknames.go
 os/user.lo.dep: $(extra_go_files_os_user)
 
 extra_check_libs_cmd_go_internal_cache = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_go_internal_fsys = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_generate = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_get = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_load = $(abs_builddir)/libgotool.a
@@ -1075,10 +1077,14 @@ extra_check_libs_cmd_go_internal_modload = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_module = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_mvs = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_search = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_go_internal_str = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_test = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_go_internal_vcs = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_web2 = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_work = $(abs_builddir)/libgotool.a
 
+extra_check_libs_cmd_internal_buildid = $(abs_builddir)/libgotool.a
+
 extra_check_libs_cmd_vet_internal_cfg = $(abs_builddir)/libgotool.a
 
 # FIXME: The following C files may as well move to the runtime
@@ -1122,6 +1128,11 @@ syscall/wait.lo: go/syscall/wait.c runtime.inc
 	@$(MKDIR_P) syscall
 	$(LTCOMPILE) -c -o $@ $(srcdir)/go/syscall/wait.c
 
+# An os function is written in C.
+os/dir_gccgo_c.lo: go/os/dir_gccgo_c.c runtime.inc
+	@$(MKDIR_P) os
+	$(LTCOMPILE) -c -o $@ $(srcdir)/go/os/dir_gccgo_c.c
+
 # internal/cpu needs some C code.
 internal/cpu/cpu_gccgo.lo: go/internal/cpu/cpu_gccgo.c runtime.inc
 	@$(MKDIR_P) internal/cpu

libgo/Makefile.in

@@ -224,7 +224,7 @@ LTLIBRARIES = $(toolexeclib_LTLIBRARIES)
 am__DEPENDENCIES_3 = $(addsuffix .lo,$(PACKAGES)) \
 	internal/bytealg/bytealg.lo reflect/makefunc_ffi_c.lo \
 	$(am__DEPENDENCIES_1) syscall/errno.lo syscall/signame.lo \
-	syscall/wait.lo $(golangorg_x_net_lif_lo) \
+	syscall/wait.lo os/dir_gccgo_c.lo $(golangorg_x_net_lif_lo) \
 	$(golangorg_x_net_route_lo) log/syslog/syslog_c.lo \
 	runtime/internal/atomic_c.lo sync/atomic_c.lo \
 	internal/cpu/cpu_gccgo.lo $(am__DEPENDENCIES_2)
@@ -940,6 +940,7 @@ libgo_go_objs = \
 	syscall/errno.lo \
 	syscall/signame.lo \
 	syscall/wait.lo \
+	os/dir_gccgo_c.lo \
 	$(golangorg_x_net_lif_lo) \
 	$(golangorg_x_net_route_lo) \
 	log/syslog/syslog_c.lo \
@@ -1130,6 +1131,7 @@ extra_go_files_cmd_go_internal_cfg = zdefaultcc.go
 extra_go_files_os = os_linknames.go
 extra_go_files_os_user = os_user_linknames.go
 extra_check_libs_cmd_go_internal_cache = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_go_internal_fsys = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_generate = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_get = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_load = $(abs_builddir)/libgotool.a
@@ -1143,9 +1145,12 @@ extra_check_libs_cmd_go_internal_modload = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_module = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_mvs = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_search = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_go_internal_str = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_test = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_go_internal_vcs = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_web2 = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_go_internal_work = $(abs_builddir)/libgotool.a
+extra_check_libs_cmd_internal_buildid = $(abs_builddir)/libgotool.a
 extra_check_libs_cmd_vet_internal_cfg = $(abs_builddir)/libgotool.a
 @HAVE_STAT_TIMESPEC_FALSE@@LIBGO_IS_SOLARIS_TRUE@matchargs_os = 
 
@@ -3009,6 +3014,11 @@ syscall/wait.lo: go/syscall/wait.c runtime.inc
 	@$(MKDIR_P) syscall
 	$(LTCOMPILE) -c -o $@ $(srcdir)/go/syscall/wait.c
 
+# An os function is written in C.
+os/dir_gccgo_c.lo: go/os/dir_gccgo_c.c runtime.inc
+	@$(MKDIR_P) os
+	$(LTCOMPILE) -c -o $@ $(srcdir)/go/os/dir_gccgo_c.c
+
 # internal/cpu needs some C code.
 internal/cpu/cpu_gccgo.lo: go/internal/cpu/cpu_gccgo.c runtime.inc
 	@$(MKDIR_P) internal/cpu

libgo/VERSION

@@ -1 +1 @@
-go1.15.6
+go1.16beta1

libgo/check-packages.txt

@@ -3,6 +3,7 @@ archive/zip
 bufio
 bytes
 cmd/go/internal/cache
+cmd/go/internal/fsys
 cmd/go/internal/generate
 cmd/go/internal/get
 cmd/go/internal/imports
@@ -16,8 +17,10 @@ cmd/go/internal/modload
 cmd/go/internal/mvs
 cmd/go/internal/par
 cmd/go/internal/search
+cmd/go/internal/str
 cmd/go/internal/test
 cmd/go/internal/txtar
+cmd/go/internal/vcs
 cmd/go/internal/work
 cmd/internal/buildid
 cmd/internal/edit
@@ -113,6 +116,7 @@ internal/trace
 internal/unsafeheader
 internal/xcoff
 io
+io/fs
 io/ioutil
 log
 log/syslog
@@ -155,6 +159,7 @@ runtime/debug
 runtime/internal/atomic
 runtime/internal/math
 runtime/internal/sys
+runtime/metrics
 runtime/pprof
 runtime/trace
 sort
@@ -164,6 +169,7 @@ sync
 sync/atomic
 syscall
 testing
+testing/fstest
 testing/iotest
 testing/quick
 text/scanner

libgo/config.h.in

@@ -36,6 +36,10 @@
 /* Define to 1 if you have the `cosl' function. */
 #undef HAVE_COSL
 
+/* Define to 1 if you have the <dirent.h> header file, and it defines `DIR'.
+   */
+#undef HAVE_DIRENT_H
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 
@@ -159,6 +163,9 @@
 /* Define to 1 if you have the `mknodat' function. */
 #undef HAVE_MKNODAT
 
+/* Define to 1 if you have the <ndir.h> header file, and it defines `DIR'. */
+#undef HAVE_NDIR_H
+
 /* Define to 1 if you have the <netinet/icmp6.h> header file. */
 #undef HAVE_NETINET_ICMP6_H
 
@@ -249,6 +256,9 @@
 /* Define to 1 if you have the `strsignal' function. */
 #undef HAVE_STRSIGNAL
 
+/* Define to 1 if `d_type' is a member of `struct dirent'. */
+#undef HAVE_STRUCT_DIRENT_D_TYPE
+
 /* Define to 1 if <math.h> defines struct exception */
 #undef HAVE_STRUCT_EXCEPTION
 
@@ -261,6 +271,10 @@
 /* Define to 1 if you have the <syscall.h> header file. */
 #undef HAVE_SYSCALL_H
 
+/* Define to 1 if you have the <sys/dir.h> header file, and it defines `DIR'.
+   */
+#undef HAVE_SYS_DIR_H
+
 /* Define to 1 if you have the <sys/epoll.h> header file. */
 #undef HAVE_SYS_EPOLL_H
 
@@ -279,6 +293,10 @@
 /* Define to 1 if you have the <sys/mount.h> header file. */
 #undef HAVE_SYS_MOUNT_H
 
+/* Define to 1 if you have the <sys/ndir.h> header file, and it defines `DIR'.
+   */
+#undef HAVE_SYS_NDIR_H
+
 /* Define to 1 if you have the <sys/prctl.h> header file. */
 #undef HAVE_SYS_PRCTL_H
 

libgo/configure

@@ -1956,6 +1956,63 @@ fi
 
 } # ac_fn_c_check_header_mongrel
 
+# ac_fn_c_check_member LINENO AGGR MEMBER VAR INCLUDES
+# ----------------------------------------------------
+# Tries to find if the field MEMBER exists in type AGGR, after including
+# INCLUDES, setting cache variable VAR accordingly.
+ac_fn_c_check_member ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2.$3" >&5
+$as_echo_n "checking for $2.$3... " >&6; }
+if eval \${$4+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$5
+int
+main ()
+{
+static $2 ac_aggr;
+if (ac_aggr.$3)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  eval "$4=yes"
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$5
+int
+main ()
+{
+static $2 ac_aggr;
+if (sizeof ac_aggr.$3)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  eval "$4=yes"
+else
+  eval "$4=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$$4
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_member
+
 # ac_fn_c_check_type LINENO TYPE VAR INCLUDES
 # -------------------------------------------
 # Tests whether TYPE exists after having included INCLUDES, setting cache
@@ -2551,7 +2608,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 ac_config_headers="$ac_config_headers config.h"
 
 
-libtool_VERSION=18:0:0
+libtool_VERSION=19:0:0
 
 
 # Default to --enable-multilib
@@ -11497,7 +11554,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11500 "configure"
+#line 11557 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11603,7 +11660,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11606 "configure"
+#line 11663 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13923,7 +13980,7 @@ go_include="-include"
 # All known GOOS values.  This is the union of all operating systems
 # supported by the gofrontend and all operating systems supported by
 # the gc toolchain.
-ALLGOOS="aix android darwin dragonfly freebsd hurd illumos irix js linux netbsd openbsd plan9 rtems solaris windows"
+ALLGOOS="aix android darwin dragonfly freebsd hurd illumos ios irix js linux netbsd openbsd plan9 rtems solaris windows zos"
 
 is_darwin=no
 is_freebsd=no
@@ -15287,6 +15344,195 @@ else
 fi
 
 
+ac_header_dirent=no
+for ac_hdr in dirent.h sys/ndir.h sys/dir.h ndir.h; do
+  as_ac_Header=`$as_echo "ac_cv_header_dirent_$ac_hdr" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_hdr that defines DIR" >&5
+$as_echo_n "checking for $ac_hdr that defines DIR... " >&6; }
+if eval \${$as_ac_Header+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+#include <$ac_hdr>
+
+int
+main ()
+{
+if ((DIR *) 0)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  eval "$as_ac_Header=yes"
+else
+  eval "$as_ac_Header=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$$as_ac_Header
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define `$as_echo "HAVE_$ac_hdr" | $as_tr_cpp` 1
+_ACEOF
+
+ac_header_dirent=$ac_hdr; break
+fi
+
+done
+# Two versions of opendir et al. are in -ldir and -lx on SCO Xenix.
+if test $ac_header_dirent = dirent.h; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing opendir" >&5
+$as_echo_n "checking for library containing opendir... " >&6; }
+if ${ac_cv_search_opendir+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char opendir ();
+int
+main ()
+{
+return opendir ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' dir; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_opendir=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_opendir+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_opendir+:} false; then :
+
+else
+  ac_cv_search_opendir=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_opendir" >&5
+$as_echo "$ac_cv_search_opendir" >&6; }
+ac_res=$ac_cv_search_opendir
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing opendir" >&5
+$as_echo_n "checking for library containing opendir... " >&6; }
+if ${ac_cv_search_opendir+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char opendir ();
+int
+main ()
+{
+return opendir ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' x; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_opendir=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_opendir+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_opendir+:} false; then :
+
+else
+  ac_cv_search_opendir=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_opendir" >&5
+$as_echo "$ac_cv_search_opendir" >&6; }
+ac_res=$ac_cv_search_opendir
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
+fi
+
+
+
+  ac_fn_c_check_member "$LINENO" "struct dirent" "d_type" "ac_cv_member_struct_dirent_d_type" "
+#include <sys/types.h>
+#ifdef HAVE_DIRENT_H
+# include <dirent.h>
+#else
+# define dirent direct
+# ifdef HAVE_SYS_NDIR_H
+#  include <sys/ndir.h>
+# endif
+# ifdef HAVE_SYS_DIR_H
+#  include <sys/dir.h>
+# endif
+# ifdef HAVE_NDIR_H
+#  include <ndir.h>
+# endif
+#endif
+
+"
+if test "x$ac_cv_member_struct_dirent_d_type" = xyes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_DIRENT_D_TYPE 1
+_ACEOF
+
+
+fi
+
+
+
 for ac_func in accept4 dup3 epoll_create1 faccessat fallocate fchmodat fchownat futimesat getxattr inotify_add_watch inotify_init inotify_init1 inotify_rm_watch listxattr mkdirat mknodat open64 openat pipe2 removexattr renameat setxattr sync_file_range splice syscall tee unlinkat unshare utimensat
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`

libgo/configure.ac

@@ -10,7 +10,7 @@ AC_INIT(package-unused, version-unused,, libgo)
 AC_CONFIG_SRCDIR(Makefile.am)
 AC_CONFIG_HEADER(config.h)
 
-libtool_VERSION=18:0:0
+libtool_VERSION=19:0:0
 AC_SUBST(libtool_VERSION)
 
 AM_ENABLE_MULTILIB(, ..)
@@ -167,7 +167,7 @@ AC_SUBST(go_include)
 # All known GOOS values.  This is the union of all operating systems
 # supported by the gofrontend and all operating systems supported by
 # the gc toolchain.
-ALLGOOS="aix android darwin dragonfly freebsd hurd illumos irix js linux netbsd openbsd plan9 rtems solaris windows"
+ALLGOOS="aix android darwin dragonfly freebsd hurd illumos ios irix js linux netbsd openbsd plan9 rtems solaris windows zos"
 
 is_darwin=no
 is_freebsd=no
@@ -598,6 +598,8 @@ AC_CHECK_FUNCS(strerror_r strsignal wait4 mincore setenv unsetenv dl_iterate_phd
 AM_CONDITIONAL(HAVE_STRERROR_R, test "$ac_cv_func_strerror_r" = yes)
 AM_CONDITIONAL(HAVE_WAIT4, test "$ac_cv_func_wait4" = yes)
 
+AC_STRUCT_DIRENT_D_TYPE
+
 AC_CHECK_FUNCS(accept4 dup3 epoll_create1 faccessat fallocate fchmodat fchownat futimesat getxattr inotify_add_watch inotify_init inotify_init1 inotify_rm_watch listxattr mkdirat mknodat open64 openat pipe2 removexattr renameat setxattr sync_file_range splice syscall tee unlinkat unshare utimensat)
 AC_TYPE_OFF_T
 AC_CHECK_TYPES([loff_t])

libgo/go/archive/tar/common.go

@@ -13,8 +13,8 @@ package tar
 import (
 	"errors"
 	"fmt"
+	"io/fs"
 	"math"
-	"os"
 	"path"
 	"reflect"
 	"strconv"
@@ -525,12 +525,12 @@ func (h Header) allowedFormats() (format Format, paxHdrs map[string]string, err
 	return format, paxHdrs, err
 }
 
-// FileInfo returns an os.FileInfo for the Header.
+// FileInfo returns an fs.FileInfo for the Header.
-func (h *Header) FileInfo() os.FileInfo {
+func (h *Header) FileInfo() fs.FileInfo {
 	return headerFileInfo{h}
 }
 
-// headerFileInfo implements os.FileInfo.
+// headerFileInfo implements fs.FileInfo.
 type headerFileInfo struct {
 	h *Header
 }
@@ -549,57 +549,57 @@ func (fi headerFileInfo) Name() string {
 }
 
 // Mode returns the permission and mode bits for the headerFileInfo.
-func (fi headerFileInfo) Mode() (mode os.FileMode) {
+func (fi headerFileInfo) Mode() (mode fs.FileMode) {
 	// Set file permission bits.
-	mode = os.FileMode(fi.h.Mode).Perm()
+	mode = fs.FileMode(fi.h.Mode).Perm()
 
 	// Set setuid, setgid and sticky bits.
 	if fi.h.Mode&c_ISUID != 0 {
-		mode |= os.ModeSetuid
+		mode |= fs.ModeSetuid
 	}
 	if fi.h.Mode&c_ISGID != 0 {
-		mode |= os.ModeSetgid
+		mode |= fs.ModeSetgid
 	}
 	if fi.h.Mode&c_ISVTX != 0 {
-		mode |= os.ModeSticky
+		mode |= fs.ModeSticky
 	}
 
 	// Set file mode bits; clear perm, setuid, setgid, and sticky bits.
-	switch m := os.FileMode(fi.h.Mode) &^ 07777; m {
+	switch m := fs.FileMode(fi.h.Mode) &^ 07777; m {
 	case c_ISDIR:
-		mode |= os.ModeDir
+		mode |= fs.ModeDir
 	case c_ISFIFO:
-		mode |= os.ModeNamedPipe
+		mode |= fs.ModeNamedPipe
 	case c_ISLNK:
-		mode |= os.ModeSymlink
+		mode |= fs.ModeSymlink
 	case c_ISBLK:
-		mode |= os.ModeDevice
+		mode |= fs.ModeDevice
 	case c_ISCHR:
-		mode |= os.ModeDevice
+		mode |= fs.ModeDevice
-		mode |= os.ModeCharDevice
+		mode |= fs.ModeCharDevice
 	case c_ISSOCK:
-		mode |= os.ModeSocket
+		mode |= fs.ModeSocket
 	}
 
 	switch fi.h.Typeflag {
 	case TypeSymlink:
-		mode |= os.ModeSymlink
+		mode |= fs.ModeSymlink
 	case TypeChar:
-		mode |= os.ModeDevice
+		mode |= fs.ModeDevice
-		mode |= os.ModeCharDevice
+		mode |= fs.ModeCharDevice
 	case TypeBlock:
-		mode |= os.ModeDevice
+		mode |= fs.ModeDevice
 	case TypeDir:
-		mode |= os.ModeDir
+		mode |= fs.ModeDir
 	case TypeFifo:
-		mode |= os.ModeNamedPipe
+		mode |= fs.ModeNamedPipe
 	}
 
 	return mode
 }
 
 // sysStat, if non-nil, populates h from system-dependent fields of fi.
-var sysStat func(fi os.FileInfo, h *Header) error
+var sysStat func(fi fs.FileInfo, h *Header) error
 
 const (
 	// Mode constants from the USTAR spec:
@@ -623,10 +623,10 @@ const (
 // If fi describes a symlink, FileInfoHeader records link as the link target.
 // If fi describes a directory, a slash is appended to the name.
 //
-// Since os.FileInfo's Name method only returns the base name of
+// Since fs.FileInfo's Name method only returns the base name of
 // the file it describes, it may be necessary to modify Header.Name
 // to provide the full path name of the file.
-func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
+func FileInfoHeader(fi fs.FileInfo, link string) (*Header, error) {
 	if fi == nil {
 		return nil, errors.New("archive/tar: FileInfo is nil")
 	}
@@ -643,29 +643,29 @@ func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
 	case fi.IsDir():
 		h.Typeflag = TypeDir
 		h.Name += "/"
-	case fm&os.ModeSymlink != 0:
+	case fm&fs.ModeSymlink != 0:
 		h.Typeflag = TypeSymlink
 		h.Linkname = link
-	case fm&os.ModeDevice != 0:
+	case fm&fs.ModeDevice != 0:
-		if fm&os.ModeCharDevice != 0 {
+		if fm&fs.ModeCharDevice != 0 {
 			h.Typeflag = TypeChar
 		} else {
 			h.Typeflag = TypeBlock
 		}
-	case fm&os.ModeNamedPipe != 0:
+	case fm&fs.ModeNamedPipe != 0:
 		h.Typeflag = TypeFifo
-	case fm&os.ModeSocket != 0:
+	case fm&fs.ModeSocket != 0:
 		return nil, fmt.Errorf("archive/tar: sockets not supported")
 	default:
 		return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm)
 	}
-	if fm&os.ModeSetuid != 0 {
+	if fm&fs.ModeSetuid != 0 {
 		h.Mode |= c_ISUID
 	}
-	if fm&os.ModeSetgid != 0 {
+	if fm&fs.ModeSetgid != 0 {
 		h.Mode |= c_ISGID
 	}
-	if fm&os.ModeSticky != 0 {
+	if fm&fs.ModeSticky != 0 {
 		h.Mode |= c_ISVTX
 	}
 	// If possible, populate additional fields from OS-specific

libgo/go/archive/tar/reader.go

@@ -7,7 +7,6 @@ package tar
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"strconv"
 	"strings"
 	"time"
@@ -104,7 +103,7 @@ func (tr *Reader) next() (*Header, error) {
 			continue // This is a meta header affecting the next header
 		case TypeGNULongName, TypeGNULongLink:
 			format.mayOnlyBe(FormatGNU)
-			realname, err := ioutil.ReadAll(tr)
+			realname, err := io.ReadAll(tr)
 			if err != nil {
 				return nil, err
 			}
@@ -294,7 +293,7 @@ func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {
 // parsePAX parses PAX headers.
 // If an extended header (type 'x') is invalid, ErrHeader is returned
 func parsePAX(r io.Reader) (map[string]string, error) {
-	buf, err := ioutil.ReadAll(r)
+	buf, err := io.ReadAll(r)
 	if err != nil {
 		return nil, err
 	}
@@ -850,7 +849,7 @@ func discard(r io.Reader, n int64) error {
 		}
 	}
 
-	copySkipped, err := io.CopyN(ioutil.Discard, r, n-seekSkipped)
+	copySkipped, err := io.CopyN(io.Discard, r, n-seekSkipped)
 	if err == io.EOF && seekSkipped+copySkipped < n {
 		err = io.ErrUnexpectedEOF
 	}

libgo/go/archive/tar/reader_test.go

@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"path"
@@ -773,7 +772,7 @@ func TestReadTruncation(t *testing.T) {
 		"testdata/pax-path-hdr.tar",
 		"testdata/sparse-formats.tar",
 	} {
-		buf, err := ioutil.ReadFile(p)
+		buf, err := os.ReadFile(p)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -865,7 +864,7 @@ func TestReadTruncation(t *testing.T) {
 				}
 				cnt++
 				if s2 == "manual" {
-					if _, err = tr.writeTo(ioutil.Discard); err != nil {
+					if _, err = tr.writeTo(io.Discard); err != nil {
 						break
 					}
 				}

libgo/go/archive/tar/stat_unix.go

@@ -7,7 +7,7 @@
 package tar
 
 import (
-	"os"
+	"io/fs"
 	"os/user"
 	"runtime"
 	"strconv"
@@ -23,7 +23,7 @@ func init() {
 // The downside is that renaming uname or gname by the OS never takes effect.
 var userMap, groupMap sync.Map // map[int]string
 
-func statUnix(fi os.FileInfo, h *Header) error {
+func statUnix(fi fs.FileInfo, h *Header) error {
 	sys, ok := fi.Sys().(*syscall.Stat_t)
 	if !ok {
 		return nil
@@ -71,7 +71,7 @@ func statUnix(fi os.FileInfo, h *Header) error {
 			minor := uint32((dev & 0x00000000000000ff) >> 0)
 			minor |= uint32((dev & 0x00000ffffff00000) >> 12)
 			h.Devmajor, h.Devminor = int64(major), int64(minor)
-		case "darwin":
+		case "darwin", "ios":
 			// Copied from golang.org/x/sys/unix/dev_darwin.go.
 			major := uint32((dev >> 24) & 0xff)
 			minor := uint32(dev & 0xffffff)

libgo/go/archive/tar/tar_test.go

@@ -10,7 +10,7 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"math"
 	"os"
 	"path"
@@ -262,7 +262,7 @@ func TestFileInfoHeaderDir(t *testing.T) {
 func TestFileInfoHeaderSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestFileInfoHeaderSymlink")
+	tmpdir, err := os.MkdirTemp("", "TestFileInfoHeaderSymlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -327,7 +327,7 @@ func TestRoundTrip(t *testing.T) {
 	if !reflect.DeepEqual(rHdr, hdr) {
 		t.Errorf("Header mismatch.\n got %+v\nwant %+v", rHdr, hdr)
 	}
-	rData, err := ioutil.ReadAll(tr)
+	rData, err := io.ReadAll(tr)
 	if err != nil {
 		t.Fatalf("Read: %v", err)
 	}
@@ -338,7 +338,7 @@ func TestRoundTrip(t *testing.T) {
 
 type headerRoundTripTest struct {
 	h  *Header
-	fm os.FileMode
+	fm fs.FileMode
 }
 
 func TestHeaderRoundTrip(t *testing.T) {
@@ -361,7 +361,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360600852, 0),
 			Typeflag: TypeSymlink,
 		},
-		fm: 0777 | os.ModeSymlink,
+		fm: 0777 | fs.ModeSymlink,
 	}, {
 		// character device node.
 		h: &Header{
@@ -371,7 +371,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360578951, 0),
 			Typeflag: TypeChar,
 		},
-		fm: 0666 | os.ModeDevice | os.ModeCharDevice,
+		fm: 0666 | fs.ModeDevice | fs.ModeCharDevice,
 	}, {
 		// block device node.
 		h: &Header{
@@ -381,7 +381,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360578954, 0),
 			Typeflag: TypeBlock,
 		},
-		fm: 0660 | os.ModeDevice,
+		fm: 0660 | fs.ModeDevice,
 	}, {
 		// directory.
 		h: &Header{
@@ -391,7 +391,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360601116, 0),
 			Typeflag: TypeDir,
 		},
-		fm: 0755 | os.ModeDir,
+		fm: 0755 | fs.ModeDir,
 	}, {
 		// fifo node.
 		h: &Header{
@@ -401,7 +401,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360578949, 0),
 			Typeflag: TypeFifo,
 		},
-		fm: 0600 | os.ModeNamedPipe,
+		fm: 0600 | fs.ModeNamedPipe,
 	}, {
 		// setuid.
 		h: &Header{
@@ -411,7 +411,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1355405093, 0),
 			Typeflag: TypeReg,
 		},
-		fm: 0755 | os.ModeSetuid,
+		fm: 0755 | fs.ModeSetuid,
 	}, {
 		// setguid.
 		h: &Header{
@@ -421,7 +421,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360602346, 0),
 			Typeflag: TypeReg,
 		},
-		fm: 0750 | os.ModeSetgid,
+		fm: 0750 | fs.ModeSetgid,
 	}, {
 		// sticky.
 		h: &Header{
@@ -431,7 +431,7 @@ func TestHeaderRoundTrip(t *testing.T) {
 			ModTime:  time.Unix(1360602540, 0),
 			Typeflag: TypeReg,
 		},
-		fm: 0600 | os.ModeSticky,
+		fm: 0600 | fs.ModeSticky,
 	}, {
 		// hard link.
 		h: &Header{
@@ -804,9 +804,9 @@ func Benchmark(b *testing.B) {
 			b.Run(v.label, func(b *testing.B) {
 				b.ReportAllocs()
 				for i := 0; i < b.N; i++ {
-					// Writing to ioutil.Discard because we want to
+					// Writing to io.Discard because we want to
 					// test purely the writer code and not bring in disk performance into this.
-					tw := NewWriter(ioutil.Discard)
+					tw := NewWriter(io.Discard)
 					for _, file := range v.files {
 						if err := tw.WriteHeader(file.hdr); err != nil {
 							b.Errorf("unexpected WriteHeader error: %v", err)
@@ -844,7 +844,7 @@ func Benchmark(b *testing.B) {
 					if _, err := tr.Next(); err != nil {
 						b.Errorf("unexpected Next error: %v", err)
 					}
-					if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+					if _, err := io.Copy(io.Discard, tr); err != nil {
 						b.Errorf("unexpected Copy error : %v", err)
 					}
 				}

libgo/go/archive/tar/writer_test.go

@@ -9,7 +9,6 @@ import (
 	"encoding/hex"
 	"errors"
 	"io"
-	"io/ioutil"
 	"os"
 	"path"
 	"reflect"
@@ -520,7 +519,7 @@ func TestWriter(t *testing.T) {
 			}
 
 			if v.file != "" {
-				want, err := ioutil.ReadFile(v.file)
+				want, err := os.ReadFile(v.file)
 				if err != nil {
 					t.Fatalf("ReadFile() = %v, want nil", err)
 				}

libgo/go/archive/zip/reader.go

@@ -11,7 +11,12 @@ import (
 	"hash"
 	"hash/crc32"
 	"io"
+	"io/fs"
 	"os"
+	"path"
+	"sort"
+	"strings"
+	"sync"
 	"time"
 )
 
@@ -21,18 +26,28 @@ var (
 	ErrChecksum  = errors.New("zip: checksum error")
 )
 
+// A Reader serves content from a ZIP archive.
 type Reader struct {
 	r             io.ReaderAt
 	File          []*File
 	Comment       string
 	decompressors map[uint16]Decompressor
+
+	// fileList is a list of files sorted by ename,
+	// for use by the Open method.
+	fileListOnce sync.Once
+	fileList     []fileListEntry
 }
 
+// A ReadCloser is a Reader that must be closed when no longer needed.
 type ReadCloser struct {
 	f *os.File
 	Reader
 }
 
+// A File is a single file in a ZIP archive.
+// The file information is in the embedded FileHeader.
+// The file content can be accessed by calling Open.
 type File struct {
 	FileHeader
 	zip          *Reader
@@ -187,6 +202,10 @@ type checksumReader struct {
 	err   error     // sticky error
 }
 
+func (r *checksumReader) Stat() (fs.FileInfo, error) {
+	return headerFileInfo{&r.f.FileHeader}, nil
+}
+
 func (r *checksumReader) Read(b []byte) (n int, err error) {
 	if r.err != nil {
 		return 0, r.err
@@ -607,3 +626,173 @@ func (b *readBuf) sub(n int) readBuf {
 	*b = (*b)[n:]
 	return b2
 }
+
+// A fileListEntry is a File and its ename.
+// If file == nil, the fileListEntry describes a directory, without metadata.
+type fileListEntry struct {
+	name string
+	file *File // nil for directories
+}
+
+type fileInfoDirEntry interface {
+	fs.FileInfo
+	fs.DirEntry
+}
+
+func (e *fileListEntry) stat() fileInfoDirEntry {
+	if e.file != nil {
+		return headerFileInfo{&e.file.FileHeader}
+	}
+	return e
+}
+
+// Only used for directories.
+func (f *fileListEntry) Name() string       { _, elem, _ := split(f.name); return elem }
+func (f *fileListEntry) Size() int64        { return 0 }
+func (f *fileListEntry) ModTime() time.Time { return time.Time{} }
+func (f *fileListEntry) Mode() fs.FileMode  { return fs.ModeDir | 0555 }
+func (f *fileListEntry) Type() fs.FileMode  { return fs.ModeDir }
+func (f *fileListEntry) IsDir() bool        { return true }
+func (f *fileListEntry) Sys() interface{}   { return nil }
+
+func (f *fileListEntry) Info() (fs.FileInfo, error) { return f, nil }
+
+// toValidName coerces name to be a valid name for fs.FS.Open.
+func toValidName(name string) string {
+	name = strings.ReplaceAll(name, `\`, `/`)
+	p := path.Clean(name)
+	if strings.HasPrefix(p, "/") {
+		p = p[len("/"):]
+	}
+	for strings.HasPrefix(name, "../") {
+		p = p[len("../"):]
+	}
+	return p
+}
+
+func (r *Reader) initFileList() {
+	r.fileListOnce.Do(func() {
+		dirs := make(map[string]bool)
+		for _, file := range r.File {
+			name := toValidName(file.Name)
+			for dir := path.Dir(name); dir != "."; dir = path.Dir(dir) {
+				dirs[dir] = true
+			}
+			r.fileList = append(r.fileList, fileListEntry{name, file})
+		}
+		for dir := range dirs {
+			r.fileList = append(r.fileList, fileListEntry{dir + "/", nil})
+		}
+
+		sort.Slice(r.fileList, func(i, j int) bool { return fileEntryLess(r.fileList[i].name, r.fileList[j].name) })
+	})
+}
+
+func fileEntryLess(x, y string) bool {
+	xdir, xelem, _ := split(x)
+	ydir, yelem, _ := split(y)
+	return xdir < ydir || xdir == ydir && xelem < yelem
+}
+
+// Open opens the named file in the ZIP archive,
+// using the semantics of fs.FS.Open:
+// paths are always slash separated, with no
+// leading / or ../ elements.
+func (r *Reader) Open(name string) (fs.File, error) {
+	r.initFileList()
+
+	e := r.openLookup(name)
+	if e == nil || !fs.ValidPath(name) {
+		return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrNotExist}
+	}
+	if e.file == nil || strings.HasSuffix(e.file.Name, "/") {
+		return &openDir{e, r.openReadDir(name), 0}, nil
+	}
+	rc, err := e.file.Open()
+	if err != nil {
+		return nil, err
+	}
+	return rc.(fs.File), nil
+}
+
+func split(name string) (dir, elem string, isDir bool) {
+	if name[len(name)-1] == '/' {
+		isDir = true
+		name = name[:len(name)-1]
+	}
+	i := len(name) - 1
+	for i >= 0 && name[i] != '/' {
+		i--
+	}
+	if i < 0 {
+		return ".", name, isDir
+	}
+	return name[:i], name[i+1:], isDir
+}
+
+var dotFile = &fileListEntry{name: "./"}
+
+func (r *Reader) openLookup(name string) *fileListEntry {
+	if name == "." {
+		return dotFile
+	}
+
+	dir, elem, _ := split(name)
+	files := r.fileList
+	i := sort.Search(len(files), func(i int) bool {
+		idir, ielem, _ := split(files[i].name)
+		return idir > dir || idir == dir && ielem >= elem
+	})
+	if i < len(files) {
+		fname := files[i].name
+		if fname == name || len(fname) == len(name)+1 && fname[len(name)] == '/' && fname[:len(name)] == name {
+			return &files[i]
+		}
+	}
+	return nil
+}
+
+func (r *Reader) openReadDir(dir string) []fileListEntry {
+	files := r.fileList
+	i := sort.Search(len(files), func(i int) bool {
+		idir, _, _ := split(files[i].name)
+		return idir >= dir
+	})
+	j := sort.Search(len(files), func(j int) bool {
+		jdir, _, _ := split(files[j].name)
+		return jdir > dir
+	})
+	return files[i:j]
+}
+
+type openDir struct {
+	e      *fileListEntry
+	files  []fileListEntry
+	offset int
+}
+
+func (d *openDir) Close() error               { return nil }
+func (d *openDir) Stat() (fs.FileInfo, error) { return d.e.stat(), nil }
+
+func (d *openDir) Read([]byte) (int, error) {
+	return 0, &fs.PathError{Op: "read", Path: d.e.name, Err: errors.New("is a directory")}
+}
+
+func (d *openDir) ReadDir(count int) ([]fs.DirEntry, error) {
+	n := len(d.files) - d.offset
+	if count > 0 && n > count {
+		n = count
+	}
+	if n == 0 {
+		if count <= 0 {
+			return nil, nil
+		}
+		return nil, io.EOF
+	}
+	list := make([]fs.DirEntry, n)
+	for i := range list {
+		list[i] = d.files[d.offset+i].stat()
+	}
+	d.offset += n
+	return list, nil
+}

libgo/go/archive/zip/reader_test.go

@@ -10,12 +10,13 @@ import (
 	"encoding/hex"
 	"internal/obscuretestdata"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
 	"testing"
+	"testing/fstest"
 	"time"
 )
 
@@ -30,7 +31,7 @@ type ZipTest struct {
 
 type ZipTestFile struct {
 	Name     string
-	Mode     os.FileMode
+	Mode     fs.FileMode
 	NonUTF8  bool
 	ModTime  time.Time
 	Modified time.Time
@@ -107,7 +108,7 @@ var tests = []ZipTest{
 				Name:     "symlink",
 				Content:  []byte("../target"),
 				Modified: time.Date(2012, 2, 3, 19, 56, 48, 0, timeZone(-2*time.Hour)),
-				Mode:     0777 | os.ModeSymlink,
+				Mode:     0777 | fs.ModeSymlink,
 			},
 		},
 	},
@@ -149,7 +150,7 @@ var tests = []ZipTest{
 				Name:     "dir/empty/",
 				Content:  []byte{},
 				Modified: time.Date(2011, 12, 8, 10, 8, 6, 0, time.UTC),
-				Mode:     os.ModeDir | 0777,
+				Mode:     fs.ModeDir | 0777,
 			},
 			{
 				Name:     "readonly",
@@ -179,7 +180,7 @@ var tests = []ZipTest{
 				Name:     "dir/empty/",
 				Content:  []byte{},
 				Modified: time.Date(2011, 12, 8, 10, 8, 6, 0, timeZone(0)),
-				Mode:     os.ModeDir | 0777,
+				Mode:     fs.ModeDir | 0777,
 			},
 			{
 				Name:     "readonly",
@@ -627,7 +628,7 @@ func readTestFile(t *testing.T, zt ZipTest, ft ZipTestFile, f *File) {
 	var c []byte
 	if ft.Content != nil {
 		c = ft.Content
-	} else if c, err = ioutil.ReadFile("testdata/" + ft.File); err != nil {
+	} else if c, err = os.ReadFile("testdata/" + ft.File); err != nil {
 		t.Error(err)
 		return
 	}
@@ -645,7 +646,7 @@ func readTestFile(t *testing.T, zt ZipTest, ft ZipTestFile, f *File) {
 	}
 }
 
-func testFileMode(t *testing.T, f *File, want os.FileMode) {
+func testFileMode(t *testing.T, f *File, want fs.FileMode) {
 	mode := f.Mode()
 	if want == 0 {
 		t.Errorf("%s mode: got %v, want none", f.Name, mode)
@@ -683,7 +684,7 @@ func TestInvalidFiles(t *testing.T) {
 }
 
 func messWith(fileName string, corrupter func(b []byte)) (r io.ReaderAt, size int64) {
-	data, err := ioutil.ReadFile(filepath.Join("testdata", fileName))
+	data, err := os.ReadFile(filepath.Join("testdata", fileName))
 	if err != nil {
 		panic("Error reading " + fileName + ": " + err.Error())
 	}
@@ -790,17 +791,17 @@ func returnRecursiveZip() (r io.ReaderAt, size int64) {
 //
 //	func main() {
 //		bigZip := makeZip("big.file", io.LimitReader(zeros{}, 1<<32-1))
-//		if err := ioutil.WriteFile("/tmp/big.zip", bigZip, 0666); err != nil {
+//		if err := os.WriteFile("/tmp/big.zip", bigZip, 0666); err != nil {
 //			log.Fatal(err)
 //		}
 //
 //		biggerZip := makeZip("big.zip", bytes.NewReader(bigZip))
-//		if err := ioutil.WriteFile("/tmp/bigger.zip", biggerZip, 0666); err != nil {
+//		if err := os.WriteFile("/tmp/bigger.zip", biggerZip, 0666); err != nil {
 //			log.Fatal(err)
 //		}
 //
 //		biggestZip := makeZip("bigger.zip", bytes.NewReader(biggerZip))
-//		if err := ioutil.WriteFile("/tmp/biggest.zip", biggestZip, 0666); err != nil {
+//		if err := os.WriteFile("/tmp/biggest.zip", biggestZip, 0666); err != nil {
 //			log.Fatal(err)
 //		}
 //	}
@@ -928,7 +929,7 @@ func returnBigZipBytes() (r io.ReaderAt, size int64) {
 		if err != nil {
 			panic(err)
 		}
-		b, err = ioutil.ReadAll(f)
+		b, err = io.ReadAll(f)
 		if err != nil {
 			panic(err)
 		}
@@ -985,7 +986,7 @@ func TestIssue10957(t *testing.T) {
 			continue
 		}
 		if f.UncompressedSize64 < 1e6 {
-			n, err := io.Copy(ioutil.Discard, r)
+			n, err := io.Copy(io.Discard, r)
 			if i == 3 && err != io.ErrUnexpectedEOF {
 				t.Errorf("File[3] error = %v; want io.ErrUnexpectedEOF", err)
 			}
@@ -1027,7 +1028,7 @@ func TestIssue11146(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	_, err = ioutil.ReadAll(r)
+	_, err = io.ReadAll(r)
 	if err != io.ErrUnexpectedEOF {
 		t.Errorf("File[0] error = %v; want io.ErrUnexpectedEOF", err)
 	}
@@ -1070,3 +1071,13 @@ func TestIssue12449(t *testing.T) {
 		t.Errorf("Error reading the archive: %v", err)
 	}
 }
+
+func TestFS(t *testing.T) {
+	z, err := OpenReader("testdata/unix.zip")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := fstest.TestFS(z, "hello", "dir/bar", "dir/empty", "readonly"); err != nil {
+		t.Fatal(err)
+	}
+}

libgo/go/archive/zip/register.go

@@ -8,7 +8,6 @@ import (
 	"compress/flate"
 	"errors"
 	"io"
-	"io/ioutil"
 	"sync"
 )
 
@@ -111,7 +110,7 @@ func init() {
 	compressors.Store(Store, Compressor(func(w io.Writer) (io.WriteCloser, error) { return &nopCloser{w}, nil }))
 	compressors.Store(Deflate, Compressor(func(w io.Writer) (io.WriteCloser, error) { return newFlateWriter(w), nil }))
 
-	decompressors.Store(Store, Decompressor(ioutil.NopCloser))
+	decompressors.Store(Store, Decompressor(io.NopCloser))
 	decompressors.Store(Deflate, Decompressor(newFlateReader))
 }
 

libgo/go/archive/zip/struct.go

@@ -20,7 +20,7 @@ fields must be used instead.
 package zip
 
 import (
-	"os"
+	"io/fs"
 	"path"
 	"time"
 )
@@ -137,12 +137,12 @@ type FileHeader struct {
 	ExternalAttrs      uint32 // Meaning depends on CreatorVersion
 }
 
-// FileInfo returns an os.FileInfo for the FileHeader.
+// FileInfo returns an fs.FileInfo for the FileHeader.
-func (h *FileHeader) FileInfo() os.FileInfo {
+func (h *FileHeader) FileInfo() fs.FileInfo {
 	return headerFileInfo{h}
 }
 
-// headerFileInfo implements os.FileInfo.
+// headerFileInfo implements fs.FileInfo.
 type headerFileInfo struct {
 	fh *FileHeader
 }
@@ -161,17 +161,20 @@ func (fi headerFileInfo) ModTime() time.Time {
 	}
 	return fi.fh.Modified.UTC()
 }
-func (fi headerFileInfo) Mode() os.FileMode { return fi.fh.Mode() }
+func (fi headerFileInfo) Mode() fs.FileMode { return fi.fh.Mode() }
+func (fi headerFileInfo) Type() fs.FileMode { return fi.fh.Mode().Type() }
 func (fi headerFileInfo) Sys() interface{}  { return fi.fh }
 
+func (fi headerFileInfo) Info() (fs.FileInfo, error) { return fi, nil }
+
 // FileInfoHeader creates a partially-populated FileHeader from an
-// os.FileInfo.
+// fs.FileInfo.
-// Because os.FileInfo's Name method returns only the base name of
+// Because fs.FileInfo's Name method returns only the base name of
 // the file it describes, it may be necessary to modify the Name field
 // of the returned header to provide the full path name of the file.
 // If compression is desired, callers should set the FileHeader.Method
 // field; it is unset by default.
-func FileInfoHeader(fi os.FileInfo) (*FileHeader, error) {
+func FileInfoHeader(fi fs.FileInfo) (*FileHeader, error) {
 	size := fi.Size()
 	fh := &FileHeader{
 		Name:               fi.Name(),
@@ -280,7 +283,7 @@ const (
 )
 
 // Mode returns the permission and mode bits for the FileHeader.
-func (h *FileHeader) Mode() (mode os.FileMode) {
+func (h *FileHeader) Mode() (mode fs.FileMode) {
 	switch h.CreatorVersion >> 8 {
 	case creatorUnix, creatorMacOSX:
 		mode = unixModeToFileMode(h.ExternalAttrs >> 16)
@@ -288,18 +291,18 @@ func (h *FileHeader) Mode() (mode os.FileMode) {
 		mode = msdosModeToFileMode(h.ExternalAttrs)
 	}
 	if len(h.Name) > 0 && h.Name[len(h.Name)-1] == '/' {
-		mode |= os.ModeDir
+		mode |= fs.ModeDir
 	}
 	return mode
 }
 
 // SetMode changes the permission and mode bits for the FileHeader.
-func (h *FileHeader) SetMode(mode os.FileMode) {
+func (h *FileHeader) SetMode(mode fs.FileMode) {
 	h.CreatorVersion = h.CreatorVersion&0xff | creatorUnix<<8
 	h.ExternalAttrs = fileModeToUnixMode(mode) << 16
 
 	// set MSDOS attributes too, as the original zip does.
-	if mode&os.ModeDir != 0 {
+	if mode&fs.ModeDir != 0 {
 		h.ExternalAttrs |= msdosDir
 	}
 	if mode&0200 == 0 {
@@ -312,9 +315,9 @@ func (h *FileHeader) isZip64() bool {
 	return h.CompressedSize64 >= uint32max || h.UncompressedSize64 >= uint32max
 }
 
-func msdosModeToFileMode(m uint32) (mode os.FileMode) {
+func msdosModeToFileMode(m uint32) (mode fs.FileMode) {
 	if m&msdosDir != 0 {
-		mode = os.ModeDir | 0777
+		mode = fs.ModeDir | 0777
 	} else {
 		mode = 0666
 	}
@@ -324,64 +327,64 @@ func msdosModeToFileMode(m uint32) (mode os.FileMode) {
 	return mode
 }
 
-func fileModeToUnixMode(mode os.FileMode) uint32 {
+func fileModeToUnixMode(mode fs.FileMode) uint32 {
 	var m uint32
-	switch mode & os.ModeType {
+	switch mode & fs.ModeType {
 	default:
 		m = s_IFREG
-	case os.ModeDir:
+	case fs.ModeDir:
 		m = s_IFDIR
-	case os.ModeSymlink:
+	case fs.ModeSymlink:
 		m = s_IFLNK
-	case os.ModeNamedPipe:
+	case fs.ModeNamedPipe:
 		m = s_IFIFO
-	case os.ModeSocket:
+	case fs.ModeSocket:
 		m = s_IFSOCK
-	case os.ModeDevice:
+	case fs.ModeDevice:
-		if mode&os.ModeCharDevice != 0 {
+		if mode&fs.ModeCharDevice != 0 {
 			m = s_IFCHR
 		} else {
 			m = s_IFBLK
 		}
 	}
-	if mode&os.ModeSetuid != 0 {
+	if mode&fs.ModeSetuid != 0 {
 		m |= s_ISUID
 	}
-	if mode&os.ModeSetgid != 0 {
+	if mode&fs.ModeSetgid != 0 {
 		m |= s_ISGID
 	}
-	if mode&os.ModeSticky != 0 {
+	if mode&fs.ModeSticky != 0 {
 		m |= s_ISVTX
 	}
 	return m | uint32(mode&0777)
 }
 
-func unixModeToFileMode(m uint32) os.FileMode {
+func unixModeToFileMode(m uint32) fs.FileMode {
-	mode := os.FileMode(m & 0777)
+	mode := fs.FileMode(m & 0777)
 	switch m & s_IFMT {
 	case s_IFBLK:
-		mode |= os.ModeDevice
+		mode |= fs.ModeDevice
 	case s_IFCHR:
-		mode |= os.ModeDevice | os.ModeCharDevice
+		mode |= fs.ModeDevice | fs.ModeCharDevice
 	case s_IFDIR:
-		mode |= os.ModeDir
+		mode |= fs.ModeDir
 	case s_IFIFO:
-		mode |= os.ModeNamedPipe
+		mode |= fs.ModeNamedPipe
 	case s_IFLNK:
-		mode |= os.ModeSymlink
+		mode |= fs.ModeSymlink
 	case s_IFREG:
 		// nothing to do
 	case s_IFSOCK:
-		mode |= os.ModeSocket
+		mode |= fs.ModeSocket
 	}
 	if m&s_ISGID != 0 {
-		mode |= os.ModeSetgid
+		mode |= fs.ModeSetgid
 	}
 	if m&s_ISUID != 0 {
-		mode |= os.ModeSetuid
+		mode |= fs.ModeSetuid
 	}
 	if m&s_ISVTX != 0 {
-		mode |= os.ModeSticky
+		mode |= fs.ModeSticky
 	}
 	return mode
 }

libgo/go/archive/zip/writer_test.go

@@ -9,7 +9,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"math/rand"
 	"os"
 	"strings"
@@ -23,7 +23,7 @@ type WriteTest struct {
 	Name   string
 	Data   []byte
 	Method uint16
-	Mode   os.FileMode
+	Mode   fs.FileMode
 }
 
 var writeTests = []WriteTest{
@@ -43,19 +43,19 @@ var writeTests = []WriteTest{
 		Name:   "setuid",
 		Data:   []byte("setuid file"),
 		Method: Deflate,
-		Mode:   0755 | os.ModeSetuid,
+		Mode:   0755 | fs.ModeSetuid,
 	},
 	{
 		Name:   "setgid",
 		Data:   []byte("setgid file"),
 		Method: Deflate,
-		Mode:   0755 | os.ModeSetgid,
+		Mode:   0755 | fs.ModeSetgid,
 	},
 	{
 		Name:   "symlink",
 		Data:   []byte("../link/target"),
 		Method: Deflate,
-		Mode:   0755 | os.ModeSymlink,
+		Mode:   0755 | fs.ModeSymlink,
 	},
 }
 
@@ -237,7 +237,7 @@ func TestWriterTime(t *testing.T) {
 		t.Fatalf("unexpected Close error: %v", err)
 	}
 
-	want, err := ioutil.ReadFile("testdata/time-go.zip")
+	want, err := os.ReadFile("testdata/time-go.zip")
 	if err != nil {
 		t.Fatalf("unexpected ReadFile error: %v", err)
 	}
@@ -301,7 +301,7 @@ func TestWriterFlush(t *testing.T) {
 }
 
 func TestWriterDir(t *testing.T) {
-	w := NewWriter(ioutil.Discard)
+	w := NewWriter(io.Discard)
 	dw, err := w.Create("dir/")
 	if err != nil {
 		t.Fatal(err)
@@ -380,7 +380,7 @@ func testReadFile(t *testing.T, f *File, wt *WriteTest) {
 	if err != nil {
 		t.Fatal("opening:", err)
 	}
-	b, err := ioutil.ReadAll(rc)
+	b, err := io.ReadAll(rc)
 	if err != nil {
 		t.Fatal("reading:", err)
 	}

libgo/go/archive/zip/zip_test.go

@@ -13,7 +13,6 @@ import (
 	"hash"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"runtime"
 	"sort"
 	"strings"
@@ -620,7 +619,7 @@ func testZip64(t testing.TB, size int64) *rleBuffer {
 			t.Fatal("read:", err)
 		}
 	}
-	gotEnd, err := ioutil.ReadAll(rc)
+	gotEnd, err := io.ReadAll(rc)
 	if err != nil {
 		t.Fatal("read end:", err)
 	}

libgo/go/bufio/bufio.go

@@ -425,7 +425,7 @@ func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error) {
 // of bytes in the combined first two elements, error).
 // The complete result is equal to
 // `bytes.Join(append(fullBuffers, finalFragment), nil)`, which has a
-// length of `totalLen`. The result is strucured in this way to allow callers
+// length of `totalLen`. The result is structured in this way to allow callers
 // to minimize allocations and copies.
 func (b *Reader) collectFragments(delim byte) (fullBuffers [][]byte, finalFragment []byte, totalLen int, err error) {
 	var frag []byte

libgo/go/bufio/bufio_test.go

@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"strings"
 	"testing"
 	"testing/iotest"
@@ -147,7 +146,7 @@ func TestReader(t *testing.T) {
 	for i := 0; i < len(texts)-1; i++ {
 		texts[i] = str + "\n"
 		all += texts[i]
-		str += string(rune(i)%26 + 'a')
+		str += string(rune(i%26 + 'a'))
 	}
 	texts[len(texts)-1] = all
 
@@ -886,7 +885,7 @@ func TestReadEmptyBuffer(t *testing.T) {
 
 func TestLinesAfterRead(t *testing.T) {
 	l := NewReaderSize(bytes.NewReader([]byte("foo")), minReadBufferSize)
-	_, err := ioutil.ReadAll(l)
+	_, err := io.ReadAll(l)
 	if err != nil {
 		t.Error(err)
 		return
@@ -1130,7 +1129,7 @@ func TestWriterReadFromCounts(t *testing.T) {
 	}
 }
 
-// A writeCountingDiscard is like ioutil.Discard and counts the number of times
+// A writeCountingDiscard is like io.Discard and counts the number of times
 // Write is called on it.
 type writeCountingDiscard int
 
@@ -1300,7 +1299,7 @@ func TestReaderReset(t *testing.T) {
 		t.Errorf("buf = %q; want foo", buf)
 	}
 	r.Reset(strings.NewReader("bar bar"))
-	all, err := ioutil.ReadAll(r)
+	all, err := io.ReadAll(r)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1645,13 +1644,13 @@ func BenchmarkReaderWriteToOptimal(b *testing.B) {
 	buf := make([]byte, bufSize)
 	r := bytes.NewReader(buf)
 	srcReader := NewReaderSize(onlyReader{r}, 1<<10)
-	if _, ok := ioutil.Discard.(io.ReaderFrom); !ok {
+	if _, ok := io.Discard.(io.ReaderFrom); !ok {
-		b.Fatal("ioutil.Discard doesn't support ReaderFrom")
+		b.Fatal("io.Discard doesn't support ReaderFrom")
 	}
 	for i := 0; i < b.N; i++ {
 		r.Seek(0, io.SeekStart)
 		srcReader.Reset(onlyReader{r})
-		n, err := srcReader.WriteTo(ioutil.Discard)
+		n, err := srcReader.WriteTo(io.Discard)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -1722,7 +1721,7 @@ func BenchmarkReaderEmpty(b *testing.B) {
 	str := strings.Repeat("x", 16<<10)
 	for i := 0; i < b.N; i++ {
 		br := NewReader(strings.NewReader(str))
-		n, err := io.Copy(ioutil.Discard, br)
+		n, err := io.Copy(io.Discard, br)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -1737,7 +1736,7 @@ func BenchmarkWriterEmpty(b *testing.B) {
 	str := strings.Repeat("x", 1<<10)
 	bs := []byte(str)
 	for i := 0; i < b.N; i++ {
-		bw := NewWriter(ioutil.Discard)
+		bw := NewWriter(io.Discard)
 		bw.Flush()
 		bw.WriteByte('a')
 		bw.Flush()
@@ -1752,7 +1751,7 @@ func BenchmarkWriterEmpty(b *testing.B) {
 
 func BenchmarkWriterFlush(b *testing.B) {
 	b.ReportAllocs()
-	bw := NewWriter(ioutil.Discard)
+	bw := NewWriter(io.Discard)
 	str := strings.Repeat("x", 50)
 	for i := 0; i < b.N; i++ {
 		bw.WriteString(str)

libgo/go/bytes/example_test.go

@@ -30,6 +30,13 @@ func ExampleBuffer_reader() {
 	// Output: Gophers rule!
 }
 
+func ExampleBuffer_Bytes() {
+	buf := bytes.Buffer{}
+	buf.Write([]byte{'h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd'})
+	os.Stdout.Write(buf.Bytes())
+	// Output: hello world
+}
+
 func ExampleBuffer_Grow() {
 	var b bytes.Buffer
 	b.Grow(64)

libgo/go/bytes/reader_test.go

@@ -8,7 +8,6 @@ import (
 	. "bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"sync"
 	"testing"
 )
@@ -235,7 +234,7 @@ func TestReaderCopyNothing(t *testing.T) {
 	type justWriter struct {
 		io.Writer
 	}
-	discard := justWriter{ioutil.Discard} // hide ReadFrom
+	discard := justWriter{io.Discard} // hide ReadFrom
 
 	var with, withOut nErr
 	with.n, with.err = io.Copy(discard, NewReader(nil))
@@ -248,7 +247,7 @@ func TestReaderCopyNothing(t *testing.T) {
 // tests that Len is affected by reads, but Size is not.
 func TestReaderLenSize(t *testing.T) {
 	r := NewReader([]byte("abc"))
-	io.CopyN(ioutil.Discard, r, 1)
+	io.CopyN(io.Discard, r, 1)
 	if r.Len() != 2 {
 		t.Errorf("Len = %d; want 2", r.Len())
 	}
@@ -268,7 +267,7 @@ func TestReaderReset(t *testing.T) {
 	if err := r.UnreadRune(); err == nil {
 		t.Errorf("UnreadRune: expected error, got nil")
 	}
-	buf, err := ioutil.ReadAll(r)
+	buf, err := io.ReadAll(r)
 	if err != nil {
 		t.Errorf("ReadAll: unexpected error: %v", err)
 	}
@@ -314,7 +313,7 @@ func TestReaderZero(t *testing.T) {
 		t.Errorf("UnreadRune: got nil, want error")
 	}
 
-	if n, err := (&Reader{}).WriteTo(ioutil.Discard); n != 0 || err != nil {
+	if n, err := (&Reader{}).WriteTo(io.Discard); n != 0 || err != nil {
 		t.Errorf("WriteTo: got %d, %v; want 0, nil", n, err)
 	}
 }

libgo/go/cmd/buildid/buildid.go

@@ -22,21 +22,6 @@ func usage() {
 
 var wflag = flag.Bool("w", false, "write build ID")
 
-// taken from cmd/go/internal/work/buildid.go
-func hashToString(h [32]byte) string {
-	const b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
-	const chunks = 5
-	var dst [chunks * 4]byte
-	for i := 0; i < chunks; i++ {
-		v := uint32(h[3*i])<<16 | uint32(h[3*i+1])<<8 | uint32(h[3*i+2])
-		dst[4*i+0] = b64[(v>>18)&0x3F]
-		dst[4*i+1] = b64[(v>>12)&0x3F]
-		dst[4*i+2] = b64[(v>>6)&0x3F]
-		dst[4*i+3] = b64[v&0x3F]
-	}
-	return string(dst[:])
-}
-
 func main() {
 	log.SetPrefix("buildid: ")
 	log.SetFlags(0)
@@ -63,12 +48,12 @@ func main() {
 		log.Fatal(err)
 	}
 	matches, hash, err := buildid.FindAndHash(f, id, 0)
+	f.Close()
 	if err != nil {
 		log.Fatal(err)
 	}
-	f.Close()
 
-	newID := id[:strings.LastIndex(id, "/")] + "/" + hashToString(hash)
+	newID := id[:strings.LastIndex(id, "/")] + "/" + buildid.HashToString(hash)
 	if len(newID) != len(id) {
 		log.Fatalf("%s: build ID length mismatch %q vs %q", file, id, newID)
 	}
@@ -77,7 +62,7 @@ func main() {
 		return
 	}
 
-	f, err = os.OpenFile(file, os.O_WRONLY, 0)
+	f, err = os.OpenFile(file, os.O_RDWR, 0)
 	if err != nil {
 		log.Fatal(err)
 	}

libgo/go/cmd/cgo/ast.go

@@ -13,7 +13,6 @@ import (
 	"go/scanner"
 	"go/token"
 	"os"
-	"path/filepath"
 	"strings"
 )
 
@@ -44,14 +43,7 @@ func sourceLine(n ast.Node) int {
 // attached to the import "C" comment, a list of references to C.xxx,
 // a list of exported functions, and the actual AST, to be rewritten and
 // printed.
-func (f *File) ParseGo(name string, src []byte) {
+func (f *File) ParseGo(abspath string, src []byte) {
-	// Create absolute path for file, so that it will be used in error
-	// messages and recorded in debug line number information.
-	// This matches the rest of the toolchain. See golang.org/issue/5122.
-	if aname, err := filepath.Abs(name); err == nil {
-		name = aname
-	}
-
 	// Two different parses: once with comments, once without.
 	// The printer is not good enough at printing comments in the
 	// right place when we start editing the AST behind its back,
@@ -60,8 +52,8 @@ func (f *File) ParseGo(name string, src []byte) {
 	// and reprinting.
 	// In cgo mode, we ignore ast2 and just apply edits directly
 	// the text behind ast1. In godefs mode we modify and print ast2.
-	ast1 := parse(name, src, parser.ParseComments)
+	ast1 := parse(abspath, src, parser.ParseComments)
-	ast2 := parse(name, src, 0)
+	ast2 := parse(abspath, src, 0)
 
 	f.Package = ast1.Name.Name
 	f.Name = make(map[string]*Name)
@@ -88,7 +80,7 @@ func (f *File) ParseGo(name string, src []byte) {
 				cg = d.Doc
 			}
 			if cg != nil {
-				f.Preamble += fmt.Sprintf("#line %d %q\n", sourceLine(cg), name)
+				f.Preamble += fmt.Sprintf("#line %d %q\n", sourceLine(cg), abspath)
 				f.Preamble += commentText(cg) + "\n"
 				f.Preamble += "#line 1 \"cgo-generated-wrapper\"\n"
 			}

libgo/go/cmd/cgo/doc.go

@@ -112,6 +112,13 @@ The default C and C++ compilers may be changed by the CC and CXX
 environment variables, respectively; those environment variables
 may include command line options.
 
+The cgo tool will always invoke the C compiler with the source file's
+directory in the include path; i.e. -I${SRCDIR} is always implied. This
+means that if a header file foo/bar.h exists both in the source
+directory and also in the system include directory (or some other place
+specified by a -I flag), then "#include <foo/bar.h>" will always find the
+local version in preference to any other version.
+
 The cgo tool is enabled by default for native builds on systems where
 it is expected to work. It is disabled by default when
 cross-compiling. You can control this by setting the CGO_ENABLED
@@ -714,7 +721,7 @@ linkage to the desired libraries. The main function is provided by
 _cgo_main.c:
 
 	int main() { return 0; }
-	void crosscall2(void(*fn)(void*, int, uintptr_t), void *a, int c, uintptr_t ctxt) { }
+	void crosscall2(void(*fn)(void*), void *a, int c, uintptr_t ctxt) { }
 	uintptr_t _cgo_wait_runtime_init_done(void) { return 0; }
 	void _cgo_release_context(uintptr_t ctxt) { }
 	char* _cgo_topofstack(void) { return (char*)0; }

libgo/go/cmd/cgo/gcc.go

@@ -316,7 +316,7 @@ func (p *Package) guessKinds(f *File) []*Name {
 			continue
 		}
 
-		if goos == "darwin" && strings.HasSuffix(n.C, "Ref") {
+		if (goos == "darwin" || goos == "ios") && strings.HasSuffix(n.C, "Ref") {
 			// For FooRef, find out if FooGetTypeID exists.
 			s := n.C[:len(n.C)-3] + "GetTypeID"
 			n := &Name{Go: s, C: s}
@@ -387,7 +387,18 @@ func (p *Package) guessKinds(f *File) []*Name {
 	fmt.Fprintf(&b, "#line 1 \"completed\"\n"+
 		"int __cgo__1 = __cgo__2;\n")
 
-	stderr := p.gccErrors(b.Bytes())
+	// We need to parse the output from this gcc command, so ensure that it
+	// doesn't have any ANSI escape sequences in it. (TERM=dumb is
+	// insufficient; if the user specifies CGO_CFLAGS=-fdiagnostics-color,
+	// GCC will ignore TERM, and GCC can also be configured at compile-time
+	// to ignore TERM.)
+	stderr := p.gccErrors(b.Bytes(), "-fdiagnostics-color=never")
+	if strings.Contains(stderr, "unrecognized command line option") {
+		// We're using an old version of GCC that doesn't understand
+		// -fdiagnostics-color. Those versions can't print color anyway,
+		// so just rerun without that option.
+		stderr = p.gccErrors(b.Bytes())
+	}
 	if stderr == "" {
 		fatalf("%s produced no output\non input:\n%s", p.gccBaseCmd()[0], b.Bytes())
 	}
@@ -1995,22 +2006,25 @@ func (p *Package) gccDefines(stdin []byte) string {
 // gccErrors runs gcc over the C program stdin and returns
 // the errors that gcc prints. That is, this function expects
 // gcc to fail.
-func (p *Package) gccErrors(stdin []byte) string {
+func (p *Package) gccErrors(stdin []byte, extraArgs ...string) string {
 	// TODO(rsc): require failure
 	args := p.gccCmd()
 
 	// Optimization options can confuse the error messages; remove them.
-	nargs := make([]string, 0, len(args))
+	nargs := make([]string, 0, len(args)+len(extraArgs))
 	for _, arg := range args {
 		if !strings.HasPrefix(arg, "-O") {
 			nargs = append(nargs, arg)
 		}
 	}
 
-	// Force -O0 optimization but keep the trailing "-" at the end.
+	// Force -O0 optimization and append extra arguments, but keep the
-	nargs = append(nargs, "-O0")
+	// trailing "-" at the end.
-	nl := len(nargs)
+	li := len(nargs) - 1
-	nargs[nl-2], nargs[nl-1] = nargs[nl-1], nargs[nl-2]
+	last := nargs[li]
+	nargs[li] = "-O0"
+	nargs = append(nargs, extraArgs...)
+	nargs = append(nargs, last)
 
 	if *debugGcc {
 		fmt.Fprintf(os.Stderr, "$ %s <<EOF\n", strings.Join(nargs, " "))
@@ -2856,21 +2870,11 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 		tgo := t.Go
 		size := t.Size
 		talign := t.Align
-		if f.BitSize > 0 {
+		if f.BitOffset > 0 || f.BitSize > 0 {
-			switch f.BitSize {
+			// The layout of bitfields is implementation defined,
-			case 8, 16, 32, 64:
+			// so we don't know how they correspond to Go fields
-			default:
+			// even if they are aligned at byte boundaries.
-				continue
+			continue
-			}
-			size = f.BitSize / 8
-			name := tgo.(*ast.Ident).String()
-			if strings.HasPrefix(name, "int") {
-				name = "int"
-			} else {
-				name = "uint"
-			}
-			tgo = ast.NewIdent(name + fmt.Sprint(f.BitSize))
-			talign = size
 		}
 
 		if talign > 0 && f.ByteOffset%talign != 0 {
@@ -3096,7 +3100,7 @@ func (c *typeConv) badCFType(dt *dwarf.TypedefType) bool {
 	// We identify the correct set of types as those ending in Ref and for which
 	// there exists a corresponding GetTypeID function.
 	// See comment below for details about the bad pointers.
-	if goos != "darwin" {
+	if goos != "darwin" && goos != "ios" {
 		return false
 	}
 	s := dt.Name

libgo/go/cmd/cgo/godefs.go

@@ -16,7 +16,7 @@ import (
 )
 
 // godefs returns the output for -godefs mode.
-func (p *Package) godefs(f *File, srcfile string) string {
+func (p *Package) godefs(f *File) string {
 	var buf bytes.Buffer
 
 	fmt.Fprintf(&buf, "// Code generated by cmd/cgo -godefs; DO NOT EDIT.\n")

libgo/go/cmd/cgo/main.go

@@ -247,6 +247,8 @@ var gccgopkgpath = flag.String("gccgopkgpath", "", "-fgo-pkgpath option used wit
 var gccgoMangler func(string) string
 var importRuntimeCgo = flag.Bool("import_runtime_cgo", true, "import runtime/cgo in generated code")
 var importSyscall = flag.Bool("import_syscall", true, "import syscall in generated code")
+var trimpath = flag.String("trimpath", "", "applies supplied rewrites or trims prefixes to recorded source file paths")
+
 var goarch, goos string
 
 func main() {
@@ -326,6 +328,13 @@ func main() {
 			input = filepath.Join(*srcDir, input)
 		}
 
+		// Create absolute path for file, so that it will be used in error
+		// messages and recorded in debug line number information.
+		// This matches the rest of the toolchain. See golang.org/issue/5122.
+		if aname, err := filepath.Abs(input); err == nil {
+			input = aname
+		}
+
 		b, err := ioutil.ReadFile(input)
 		if err != nil {
 			fatalf("%s", err)
@@ -334,6 +343,10 @@ func main() {
 			fatalf("%s", err)
 		}
 
+		// Apply trimpath to the file path. The path won't be read from after this point.
+		input, _ = objabi.ApplyRewrites(input, *trimpath)
+		goFiles[i] = input
+
 		f := new(File)
 		f.Edit = edit.NewBuffer(b)
 		f.ParseGo(input, b)
@@ -371,7 +384,7 @@ func main() {
 		p.PackagePath = f.Package
 		p.Record(f)
 		if *godefs {
-			os.Stdout.WriteString(p.godefs(f, input))
+			os.Stdout.WriteString(p.godefs(f))
 		} else {
 			p.writeOutput(f, input)
 		}

libgo/go/cmd/cgo/out.go

@@ -64,14 +64,14 @@ func (p *Package) writeDefs() {
 	// Write C main file for using gcc to resolve imports.
 	fmt.Fprintf(fm, "int main() { return 0; }\n")
 	if *importRuntimeCgo {
-		fmt.Fprintf(fm, "void crosscall2(void(*fn)(void*, int, __SIZE_TYPE__), void *a, int c, __SIZE_TYPE__ ctxt) { }\n")
+		fmt.Fprintf(fm, "void crosscall2(void(*fn)(void*), void *a, int c, __SIZE_TYPE__ ctxt) { }\n")
 		fmt.Fprintf(fm, "__SIZE_TYPE__ _cgo_wait_runtime_init_done(void) { return 0; }\n")
 		fmt.Fprintf(fm, "void _cgo_release_context(__SIZE_TYPE__ ctxt) { }\n")
 		fmt.Fprintf(fm, "char* _cgo_topofstack(void) { return (char*)0; }\n")
 	} else {
 		// If we're not importing runtime/cgo, we *are* runtime/cgo,
 		// which provides these functions. We just need a prototype.
-		fmt.Fprintf(fm, "void crosscall2(void(*fn)(void*, int, __SIZE_TYPE__), void *a, int c, __SIZE_TYPE__ ctxt);\n")
+		fmt.Fprintf(fm, "void crosscall2(void(*fn)(void*), void *a, int c, __SIZE_TYPE__ ctxt);\n")
 		fmt.Fprintf(fm, "__SIZE_TYPE__ _cgo_wait_runtime_init_done(void);\n")
 		fmt.Fprintf(fm, "void _cgo_release_context(__SIZE_TYPE__);\n")
 	}
@@ -251,6 +251,7 @@ func (p *Package) writeDefs() {
 		if err != nil {
 			fatalf("%s", err)
 		}
+		defer fgcch.Close()
 		_, err = io.Copy(fexp, fgcch)
 		if err != nil {
 			fatalf("%s", err)
@@ -879,7 +880,7 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
 	fmt.Fprintf(fgcc, "#pragma GCC diagnostic ignored \"-Wpragmas\"\n")
 	fmt.Fprintf(fgcc, "#pragma GCC diagnostic ignored \"-Waddress-of-packed-member\"\n")
 
-	fmt.Fprintf(fgcc, "extern void crosscall2(void (*fn)(void *, int, __SIZE_TYPE__), void *, int, __SIZE_TYPE__);\n")
+	fmt.Fprintf(fgcc, "extern void crosscall2(void (*fn)(void *), void *, int, __SIZE_TYPE__);\n")
 	fmt.Fprintf(fgcc, "extern __SIZE_TYPE__ _cgo_wait_runtime_init_done(void);\n")
 	fmt.Fprintf(fgcc, "extern void _cgo_release_context(__SIZE_TYPE__);\n\n")
 	fmt.Fprintf(fgcc, "extern char* _cgo_topofstack(void);")
@@ -889,59 +890,48 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
 	for _, exp := range p.ExpFunc {
 		fn := exp.Func
 
-		// Construct a gcc struct matching the gc argument and
+		// Construct a struct that will be used to communicate
-		// result frame. The gcc struct will be compiled with
+		// arguments from C to Go. The C and Go definitions
-		// __attribute__((packed)) so all padding must be accounted
+		// just have to agree. The gcc struct will be compiled
-		// for explicitly.
+		// with __attribute__((packed)) so all padding must be
+		// accounted for explicitly.
 		ctype := "struct {\n"
+		gotype := new(bytes.Buffer)
+		fmt.Fprintf(gotype, "struct {\n")
 		off := int64(0)
 		npad := 0
-		if fn.Recv != nil {
+		argField := func(typ ast.Expr, namePat string, args ...interface{}) {
-			t := p.cgoType(fn.Recv.List[0].Type)
+			name := fmt.Sprintf(namePat, args...)
-			ctype += fmt.Sprintf("\t\t%s recv;\n", t.C)
+			t := p.cgoType(typ)
+			if off%t.Align != 0 {
+				pad := t.Align - off%t.Align
+				ctype += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad)
+				off += pad
+				npad++
+			}
+			ctype += fmt.Sprintf("\t\t%s %s;\n", t.C, name)
+			fmt.Fprintf(gotype, "\t\t%s ", name)
+			noSourceConf.Fprint(gotype, fset, typ)
+			fmt.Fprintf(gotype, "\n")
 			off += t.Size
 		}
+		if fn.Recv != nil {
+			argField(fn.Recv.List[0].Type, "recv")
+		}
 		fntype := fn.Type
 		forFieldList(fntype.Params,
 			func(i int, aname string, atype ast.Expr) {
-				t := p.cgoType(atype)
+				argField(atype, "p%d", i)
-				if off%t.Align != 0 {
-					pad := t.Align - off%t.Align
-					ctype += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad)
-					off += pad
-					npad++
-				}
-				ctype += fmt.Sprintf("\t\t%s p%d;\n", t.C, i)
-				off += t.Size
 			})
-		if off%p.PtrSize != 0 {
-			pad := p.PtrSize - off%p.PtrSize
-			ctype += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad)
-			off += pad
-			npad++
-		}
 		forFieldList(fntype.Results,
 			func(i int, aname string, atype ast.Expr) {
-				t := p.cgoType(atype)
+				argField(atype, "r%d", i)
-				if off%t.Align != 0 {
-					pad := t.Align - off%t.Align
-					ctype += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad)
-					off += pad
-					npad++
-				}
-				ctype += fmt.Sprintf("\t\t%s r%d;\n", t.C, i)
-				off += t.Size
 			})
-		if off%p.PtrSize != 0 {
-			pad := p.PtrSize - off%p.PtrSize
-			ctype += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad)
-			off += pad
-			npad++
-		}
 		if ctype == "struct {\n" {
 			ctype += "\t\tchar unused;\n" // avoid empty struct
 		}
 		ctype += "\t}"
+		fmt.Fprintf(gotype, "\t}")
 
 		// Get the return type of the wrapper function
 		// compiled by gcc.
@@ -966,7 +956,11 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
 		}
 
 		// Build the wrapper function compiled by gcc.
-		s := fmt.Sprintf("%s %s(", gccResult, exp.ExpName)
+		gccExport := ""
+		if goos == "windows" {
+			gccExport = "__declspec(dllexport)"
+		}
+		s := fmt.Sprintf("%s %s %s(", gccExport, gccResult, exp.ExpName)
 		if fn.Recv != nil {
 			s += p.cgoType(fn.Recv.List[0].Type).C.String()
 			s += " recv"
@@ -988,12 +982,23 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
 		}
 		fmt.Fprintf(fgcch, "extern %s;\n", s)
 
-		fmt.Fprintf(fgcc, "extern void _cgoexp%s_%s(void *, int, __SIZE_TYPE__);\n", cPrefix, exp.ExpName)
+		fmt.Fprintf(fgcc, "extern void _cgoexp%s_%s(void *);\n", cPrefix, exp.ExpName)
 		fmt.Fprintf(fgcc, "\nCGO_NO_SANITIZE_THREAD")
 		fmt.Fprintf(fgcc, "\n%s\n", s)
 		fmt.Fprintf(fgcc, "{\n")
 		fmt.Fprintf(fgcc, "\t__SIZE_TYPE__ _cgo_ctxt = _cgo_wait_runtime_init_done();\n")
-		fmt.Fprintf(fgcc, "\t%s %v _cgo_a;\n", ctype, p.packedAttribute())
+		// The results part of the argument structure must be
+		// initialized to 0 so the write barriers generated by
+		// the assignments to these fields in Go are safe.
+		//
+		// We use a local static variable to get the zeroed
+		// value of the argument type. This avoids including
+		// string.h for memset, and is also robust to C++
+		// types with constructors. Both GCC and LLVM optimize
+		// this into just zeroing _cgo_a.
+		fmt.Fprintf(fgcc, "\ttypedef %s %v _cgo_argtype;\n", ctype, p.packedAttribute())
+		fmt.Fprintf(fgcc, "\tstatic _cgo_argtype _cgo_zero;\n")
+		fmt.Fprintf(fgcc, "\t_cgo_argtype _cgo_a = _cgo_zero;\n")
 		if gccResult != "void" && (len(fntype.Results.List) > 1 || len(fntype.Results.List[0].Names) > 1) {
 			fmt.Fprintf(fgcc, "\t%s r;\n", gccResult)
 		}
@@ -1022,82 +1027,28 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
 		fmt.Fprintf(fgcc, "}\n")
 
 		// Build the wrapper function compiled by cmd/compile.
-		goname := "_cgoexpwrap" + cPrefix + "_"
+		// This unpacks the argument struct above and calls the Go function.
-		if fn.Recv != nil {
-			goname += fn.Recv.List[0].Names[0].Name + "_"
-		}
-		goname += exp.Func.Name.Name
 		fmt.Fprintf(fgo2, "//go:cgo_export_dynamic %s\n", exp.ExpName)
 		fmt.Fprintf(fgo2, "//go:linkname _cgoexp%s_%s _cgoexp%s_%s\n", cPrefix, exp.ExpName, cPrefix, exp.ExpName)
 		fmt.Fprintf(fgo2, "//go:cgo_export_static _cgoexp%s_%s\n", cPrefix, exp.ExpName)
-		fmt.Fprintf(fgo2, "//go:nosplit\n") // no split stack, so no use of m or g
+		fmt.Fprintf(fgo2, "func _cgoexp%s_%s(a *%s) {\n", cPrefix, exp.ExpName, gotype)
-		fmt.Fprintf(fgo2, "//go:norace\n")  // must not have race detector calls inserted
-		fmt.Fprintf(fgo2, "func _cgoexp%s_%s(a unsafe.Pointer, n int32, ctxt uintptr) {\n", cPrefix, exp.ExpName)
-		fmt.Fprintf(fgo2, "\tfn := %s\n", goname)
-		// The indirect here is converting from a Go function pointer to a C function pointer.
-		fmt.Fprintf(fgo2, "\t_cgo_runtime_cgocallback(**(**unsafe.Pointer)(unsafe.Pointer(&fn)), a, uintptr(n), ctxt);\n")
-		fmt.Fprintf(fgo2, "}\n")
 
 		fmt.Fprintf(fm, "int _cgoexp%s_%s;\n", cPrefix, exp.ExpName)
 
-		// This code uses printer.Fprint, not conf.Fprint,
-		// because we don't want //line comments in the middle
-		// of the function types.
-		fmt.Fprintf(fgo2, "\n")
-		fmt.Fprintf(fgo2, "func %s(", goname)
-		comma := false
-		if fn.Recv != nil {
-			fmt.Fprintf(fgo2, "recv ")
-			printer.Fprint(fgo2, fset, fn.Recv.List[0].Type)
-			comma = true
-		}
-		forFieldList(fntype.Params,
-			func(i int, aname string, atype ast.Expr) {
-				if comma {
-					fmt.Fprintf(fgo2, ", ")
-				}
-				fmt.Fprintf(fgo2, "p%d ", i)
-				printer.Fprint(fgo2, fset, atype)
-				comma = true
-			})
-		fmt.Fprintf(fgo2, ")")
 		if gccResult != "void" {
-			fmt.Fprint(fgo2, " (")
+			// Write results back to frame.
+			fmt.Fprintf(fgo2, "\t")
 			forFieldList(fntype.Results,
 				func(i int, aname string, atype ast.Expr) {
 					if i > 0 {
-						fmt.Fprint(fgo2, ", ")
+						fmt.Fprintf(fgo2, ", ")
 					}
-					fmt.Fprintf(fgo2, "r%d ", i)
+					fmt.Fprintf(fgo2, "a.r%d", i)
-					printer.Fprint(fgo2, fset, atype)
 				})
-			fmt.Fprint(fgo2, ")")
+			fmt.Fprintf(fgo2, " = ")
-		}
-		fmt.Fprint(fgo2, " {\n")
-		if gccResult == "void" {
-			fmt.Fprint(fgo2, "\t")
-		} else {
-			// Verify that any results don't contain any
-			// Go pointers.
-			addedDefer := false
-			forFieldList(fntype.Results,
-				func(i int, aname string, atype ast.Expr) {
-					if !p.hasPointer(nil, atype, false) {
-						return
-					}
-					if !addedDefer {
-						fmt.Fprint(fgo2, "\tdefer func() {\n")
-						addedDefer = true
-					}
-					fmt.Fprintf(fgo2, "\t\t_cgoCheckResult(r%d)\n", i)
-				})
-			if addedDefer {
-				fmt.Fprint(fgo2, "\t}()\n")
-			}
-			fmt.Fprint(fgo2, "\treturn ")
 		}
 		if fn.Recv != nil {
-			fmt.Fprintf(fgo2, "recv.")
+			fmt.Fprintf(fgo2, "a.recv.")
 		}
 		fmt.Fprintf(fgo2, "%s(", exp.Func.Name)
 		forFieldList(fntype.Params,
@@ -1105,9 +1056,20 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) {
 				if i > 0 {
 					fmt.Fprint(fgo2, ", ")
 				}
-				fmt.Fprintf(fgo2, "p%d", i)
+				fmt.Fprintf(fgo2, "a.p%d", i)
 			})
 		fmt.Fprint(fgo2, ")\n")
+		if gccResult != "void" {
+			// Verify that any results don't contain any
+			// Go pointers.
+			forFieldList(fntype.Results,
+				func(i int, aname string, atype ast.Expr) {
+					if !p.hasPointer(nil, atype, false) {
+						return
+					}
+					fmt.Fprintf(fgo2, "\t_cgoCheckResult(a.r%d)\n", i)
+				})
+		}
 		fmt.Fprint(fgo2, "}\n")
 	}
 
@@ -1604,9 +1566,6 @@ const goProlog = `
 //go:linkname _cgo_runtime_cgocall runtime.cgocall
 func _cgo_runtime_cgocall(unsafe.Pointer, uintptr) int32
 
-//go:linkname _cgo_runtime_cgocallback runtime.cgocallback
-func _cgo_runtime_cgocallback(unsafe.Pointer, unsafe.Pointer, uintptr, uintptr)
-
 //go:linkname _cgoCheckPointer runtime.cgoCheckPointer
 func _cgoCheckPointer(interface{}, interface{})
 

libgo/go/cmd/go.mod

@@ -0,0 +1,12 @@
+module cmd
+
+go 1.16
+
+require (
+	github.com/google/pprof v0.0.0-20201203190320-1bf35d6f28c2
+	golang.org/x/arch v0.0.0-20201008161808-52c3e6f60cff
+	golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897
+	golang.org/x/mod v0.4.0
+	golang.org/x/sys v0.0.0-20201204225414-ed752295db88 // indirect
+	golang.org/x/tools v0.0.0-20201211025543-abf6a1d87e11
+)

libgo/go/cmd/go/alldocs.go

@@ -49,10 +49,11 @@
 // 	modules         modules, module versions, and more
 // 	module-get      module-aware go get
 // 	module-auth     module authentication using go.sum
-// 	module-private  module configuration for non-public modules
 // 	packages        package lists and patterns
+// 	private         configuration for downloading non-public code
 // 	testflag        testing flags
 // 	testfunc        testing functions
+// 	vcs             controlling version control with GOVCS
 //
 // Use "go help <topic>" for more information about that topic.
 //
@@ -71,7 +72,7 @@
 //
 // Usage:
 //
-// 	go build [-o output] [-i] [build flags] [packages]
+// 	go build [-o output] [build flags] [packages]
 //
 // Build compiles the packages named by the import paths,
 // along with their dependencies, but it does not install the results.
@@ -93,10 +94,12 @@
 //
 // The -o flag forces build to write the resulting executable or object
 // to the named output file or directory, instead of the default behavior described
-// in the last two paragraphs. If the named output is a directory that exists,
+// in the last two paragraphs. If the named output is an existing directory or
-// then any resulting executables will be written to that directory.
+// ends with a slash or backslash, then any resulting executables
+// will be written to that directory.
 //
 // The -i flag installs the packages that are dependencies of the target.
+// The -i flag is deprecated. Compiled packages are cached automatically.
 //
 // The build flags are shared by the build, clean, get, install, list, run,
 // and test commands:
@@ -161,6 +164,17 @@
 // 		directory, but it is not accessed. When -modfile is specified, an
 // 		alternate go.sum file is also used: its path is derived from the
 // 		-modfile flag by trimming the ".mod" extension and appending ".sum".
+// 	-overlay file
+// 		read a JSON config file that provides an overlay for build operations.
+// 		The file is a JSON struct with a single field, named 'Replace', that
+// 		maps each disk file path (a string) to its backing file path, so that
+// 		a build will run as if the disk file path exists with the contents
+// 		given by the backing file paths, or as if the disk file path does not
+// 		exist if its backing file path is empty. Support for the -overlay flag
+// 		has some limitations:importantly, cgo files included from outside the
+// 		include path must be  in the same directory as the Go package they are
+// 		included from, and overlays will not appear when binaries and tests are
+// 		run through go run and go test respectively.
 // 	-pkgdir dir
 // 		install and load all packages from dir instead of the usual locations.
 // 		For example, when building with a non-standard configuration,
@@ -616,15 +630,15 @@
 // dependency should be removed entirely, downgrading or removing modules
 // depending on it as needed.
 //
-// The version suffix @latest explicitly requests the latest minor release of the
+// The version suffix @latest explicitly requests the latest minor release of
-// module named by the given path. The suffix @upgrade is like @latest but
+// the module named by the given path. The suffix @upgrade is like @latest but
 // will not downgrade a module if it is already required at a revision or
 // pre-release version newer than the latest released version. The suffix
 // @patch requests the latest patch release: the latest released version
 // with the same major and minor version numbers as the currently required
 // version. Like @upgrade, @patch will not downgrade a module already required
-// at a newer version. If the path is not already required, @upgrade and @patch
+// at a newer version. If the path is not already required, @upgrade is
-// are equivalent to @latest.
+// equivalent to @latest, and @patch is disallowed.
 //
 // Although get defaults to using the latest version of the module containing
 // a named package, it does not use the latest version of that module's
@@ -661,14 +675,27 @@
 // this automatically as well.
 //
 // The -insecure flag permits fetching from repositories and resolving
-// custom domains using insecure schemes such as HTTP. Use with caution. The
+// custom domains using insecure schemes such as HTTP, and also bypassess
-// GOINSECURE environment variable is usually a better alternative, since it
+// module sum validation using the checksum database. Use with caution.
-// provides control over which modules may be retrieved using an insecure scheme.
+// This flag is deprecated and will be removed in a future version of go.
-// See 'go help environment' for details.
+// To permit the use of insecure schemes, use the GOINSECURE environment
+// variable instead. To bypass module sum validation, use GOPRIVATE or
+// GONOSUMDB. See 'go help environment' for details.
 //
 // The second step is to download (if needed), build, and install
 // the named packages.
 //
+// The -d flag instructs get to skip this step, downloading source code
+// needed to build the named packages and their dependencies, but not
+// building or installing.
+//
+// Building and installing packages with get is deprecated. In a future release,
+// the -d flag will be enabled by default, and 'go get' will be only be used to
+// adjust dependencies of the current module. To install a package using
+// dependencies from the current module, use 'go install'. To install a package
+// ignoring the current module, use 'go install' with an @version suffix like
+// "@latest" after each argument.
+//
 // If an argument names a module but not a package (because there is no
 // Go source code in the module's root directory), then the install step
 // is skipped for that argument, instead of causing a build failure.
@@ -680,10 +707,6 @@
 // adds the latest golang.org/x/perf and then installs the commands in that
 // latest version.
 //
-// The -d flag instructs get to download the source code needed to build
-// the named packages, including downloading necessary dependencies,
-// but not to build and install them.
-//
 // With no package arguments, 'go get' applies to Go package in the
 // current directory, if any. In particular, 'go get -u' and
 // 'go get -u=patch' update all the dependencies of that package.
@@ -706,7 +729,7 @@
 //
 // Usage:
 //
-// 	go install [-i] [build flags] [packages]
+// 	go install [build flags] [packages]
 //
 // Install compiles and installs the packages named by the import paths.
 //
@@ -715,11 +738,39 @@
 // environment variable is not set. Executables in $GOROOT
 // are installed in $GOROOT/bin or $GOTOOLDIR instead of $GOBIN.
 //
+// If the arguments have version suffixes (like @latest or @v1.0.0), "go install"
+// builds packages in module-aware mode, ignoring the go.mod file in the current
+// directory or any parent directory, if there is one. This is useful for
+// installing executables without affecting the dependencies of the main module.
+// To eliminate ambiguity about which module versions are used in the build, the
+// arguments must satisfy the following constraints:
+//
+// - Arguments must be package paths or package patterns (with "..." wildcards).
+//   They must not be standard packages (like fmt), meta-patterns (std, cmd,
+//   all), or relative or absolute file paths.
+// - All arguments must have the same version suffix. Different queries are not
+//   allowed, even if they refer to the same version.
+// - All arguments must refer to packages in the same module at the same version.
+// - No module is considered the "main" module. If the module containing
+//   packages named on the command line has a go.mod file, it must not contain
+//   directives (replace and exclude) that would cause it to be interpreted
+//   differently than if it were the main module. The module must not require
+//   a higher version of itself.
+// - Package path arguments must refer to main packages. Pattern arguments
+//   will only match main packages.
+//
+// If the arguments don't have version suffixes, "go install" may run in
+// module-aware mode or GOPATH mode, depending on the GO111MODULE environment
+// variable and the presence of a go.mod file. See 'go help modules' for details.
+// If module-aware mode is enabled, "go install" runs in the context of the main
+// module.
+//
 // When module-aware mode is disabled, other packages are installed in the
 // directory $GOPATH/pkg/$GOOS_$GOARCH. When module-aware mode is enabled,
 // other packages are built and cached but not installed.
 //
 // The -i flag installs the dependencies of the named packages as well.
+// The -i flag is deprecated. Compiled packages are cached automatically.
 //
 // For more about the build flags, see 'go help build'.
 // For more about specifying packages, see 'go help packages'.
@@ -766,26 +817,28 @@
 //         BinaryOnly    bool     // binary-only package (no longer supported)
 //         ForTest       string   // package is only for use in named test
 //         Export        string   // file containing export data (when using -export)
+//         BuildID       string   // build ID of the compiled package (when using -export)
 //         Module        *Module  // info about package's containing module, if any (can be nil)
 //         Match         []string // command-line patterns matching this package
 //         DepOnly       bool     // package is only a dependency, not explicitly listed
 //
 //         // Source files
-//         GoFiles         []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+//         GoFiles         []string   // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
-//         CgoFiles        []string // .go source files that import "C"
+//         CgoFiles        []string   // .go source files that import "C"
-//         CompiledGoFiles []string // .go files presented to compiler (when using -compiled)
+//         CompiledGoFiles []string   // .go files presented to compiler (when using -compiled)
-//         IgnoredGoFiles  []string // .go source files ignored due to build constraints
+//         IgnoredGoFiles  []string   // .go source files ignored due to build constraints
-//         CFiles          []string // .c source files
+//         IgnoredOtherFiles []string // non-.go source files ignored due to build constraints
-//         CXXFiles        []string // .cc, .cxx and .cpp source files
+//         CFiles          []string   // .c source files
-//         MFiles          []string // .m source files
+//         CXXFiles        []string   // .cc, .cxx and .cpp source files
-//         HFiles          []string // .h, .hh, .hpp and .hxx source files
+//         MFiles          []string   // .m source files
-//         FFiles          []string // .f, .F, .for and .f90 Fortran source files
+//         HFiles          []string   // .h, .hh, .hpp and .hxx source files
-//         SFiles          []string // .s source files
+//         FFiles          []string   // .f, .F, .for and .f90 Fortran source files
-//         SwigFiles       []string // .swig files
+//         SFiles          []string   // .s source files
-//         SwigCXXFiles    []string // .swigcxx files
+//         SwigFiles       []string   // .swig files
-//         SysoFiles       []string // .syso object files to add to archive
+//         SwigCXXFiles    []string   // .swigcxx files
-//         TestGoFiles     []string // _test.go files in package
+//         SysoFiles       []string   // .syso object files to add to archive
-//         XTestGoFiles    []string // _test.go files outside package
+//         TestGoFiles     []string   // _test.go files in package
+//         XTestGoFiles    []string   // _test.go files outside package
 //
 //         // Cgo directives
 //         CgoCFLAGS    []string // cgo: flags for C compiler
@@ -916,6 +969,7 @@
 //         Dir       string       // directory holding files for this module, if any
 //         GoMod     string       // path to go.mod file used when loading this module, if any
 //         GoVersion string       // go version used in module
+//         Retracted string       // retraction information, if any (with -retracted or -u)
 //         Error     *ModuleError // error loading module
 //     }
 //
@@ -947,14 +1001,16 @@
 // The -u flag adds information about available upgrades.
 // When the latest version of a given module is newer than
 // the current one, list -u sets the Module's Update field
-// to information about the newer module.
+// to information about the newer module. list -u will also set
+// the module's Retracted field if the current version is retracted.
 // The Module's String method indicates an available upgrade by
 // formatting the newer version in brackets after the current version.
+// If a version is retracted, the string "(retracted)" will follow it.
 // For example, 'go list -m -u all' might print:
 //
 //     my/main/module
 //     golang.org/x/text v0.3.0 [v0.4.0] => /tmp/text
-//     rsc.io/pdf v0.1.1 [v0.1.2]
+//     rsc.io/pdf v0.1.1 (retracted) [v0.1.2]
 //
 // (For tools, 'go list -m -u -json all' may be more convenient to parse.)
 //
@@ -964,6 +1020,14 @@
 // the default output format to display the module path followed by the
 // space-separated version list.
 //
+// The -retracted flag causes list to report information about retracted
+// module versions. When -retracted is used with -f or -json, the Retracted
+// field will be set to a string explaining why the version was retracted.
+// The string is taken from comments on the retract directive in the
+// module's go.mod file. When -retracted is used with -versions, retracted
+// versions are listed together with unretracted versions. The -retracted
+// flag may be used with or without -m.
+//
 // The arguments to list -m are interpreted as a list of modules, not packages.
 // The main module is the module containing the current directory.
 // The active modules are the main module and its dependencies.
@@ -1100,9 +1164,14 @@
 // module path and version pair. If the @v is omitted, a replacement without
 // a version on the left side is dropped.
 //
+// The -retract=version and -dropretract=version flags add and drop a
+// retraction on the given version. The version may be a single version
+// like "v1.2.3" or a closed interval like "[v1.1.0,v1.1.9]". Note that
+// -retract=version is a no-op if that retraction already exists.
+//
 // The -require, -droprequire, -exclude, -dropexclude, -replace,
-// and -dropreplace editing flags may be repeated, and the changes
+// -dropreplace, -retract, and -dropretract editing flags may be repeated,
-// are applied in the order given.
+// and the changes are applied in the order given.
 //
 // The -go=version flag sets the expected Go language version.
 //
@@ -1136,6 +1205,15 @@
 // 		New Module
 // 	}
 //
+// 	type Retract struct {
+// 		Low       string
+// 		High      string
+// 		Rationale string
+// 	}
+//
+// Retract entries representing a single version (not an interval) will have
+// the "Low" and "High" fields set to the same value.
+//
 // Note that this only describes the go.mod file itself, not other modules
 // referred to indirectly. For the full set of modules available to a build,
 // use 'go list -m -json all'.
@@ -1163,19 +1241,24 @@
 //
 // 	go mod init [module]
 //
-// Init initializes and writes a new go.mod to the current directory,
+// Init initializes and writes a new go.mod file in the current directory, in
-// in effect creating a new module rooted at the current directory.
+// effect creating a new module rooted at the current directory. The go.mod file
-// The file go.mod must not already exist.
+// must not already exist.
-// If possible, init will guess the module path from import comments
+//
-// (see 'go help importpath') or from version control configuration.
+// Init accepts one optional argument, the module path for the new module. If the
-// To override this guess, supply the module path as an argument.
+// module path argument is omitted, init will attempt to infer the module path
+// using import comments in .go files, vendoring tool configuration files (like
+// Gopkg.lock), and the current directory (if in GOPATH).
+//
+// If a configuration file for a vendoring tool is present, init will attempt to
+// import module requirements from it.
 //
 //
 // Add missing and remove unused modules
 //
 // Usage:
 //
-// 	go mod tidy [-v]
+// 	go mod tidy [-e] [-v]
 //
 // Tidy makes sure go.mod matches the source code in the module.
 // It adds any missing modules necessary to build the current module's
@@ -1186,12 +1269,15 @@
 // The -v flag causes tidy to print information about removed modules
 // to standard error.
 //
+// The -e flag causes tidy to attempt to proceed despite errors
+// encountered while loading packages.
+//
 //
 // Make vendored copy of dependencies
 //
 // Usage:
 //
-// 	go mod vendor [-v]
+// 	go mod vendor [-e] [-v]
 //
 // Vendor resets the main module's vendor directory to include all packages
 // needed to build and test all the main module's packages.
@@ -1200,6 +1286,9 @@
 // The -v flag causes vendor to print the names of vendored
 // modules and packages to standard error.
 //
+// The -e flag causes vendor to attempt to proceed despite errors
+// encountered while loading packages.
+//
 //
 // Verify dependencies have expected content
 //
@@ -1388,6 +1477,7 @@
 // 	-i
 // 	    Install packages that are dependencies of the test.
 // 	    Do not run the test.
+// 	    The -i flag is deprecated. Compiled packages are cached automatically.
 //
 // 	-json
 // 	    Convert test output to JSON suitable for automated processing.
@@ -1546,6 +1636,9 @@
 // Using GOOS=illumos matches build tags and files as for GOOS=solaris
 // in addition to illumos tags and files.
 //
+// Using GOOS=ios matches build tags and files as for GOOS=darwin
+// in addition to ios tags and files.
+//
 // To keep a file from being considered for the build:
 //
 // 	// +build ignore
@@ -1733,7 +1826,7 @@
 // 		Comma-separated list of glob patterns (in the syntax of Go's path.Match)
 // 		of module path prefixes that should always be fetched directly
 // 		or that should not be compared against the checksum database.
-// 		See 'go help module-private'.
+// 		See 'go help private'.
 // 	GOROOT
 // 		The root of the go tree.
 // 	GOSUMDB
@@ -1789,8 +1882,8 @@
 // 		For GOARCH=arm, the ARM architecture for which to compile.
 // 		Valid values are 5, 6, 7.
 // 	GO386
-// 		For GOARCH=386, the floating point instruction set.
+// 		For GOARCH=386, how to implement floating point instructions.
-// 		Valid values are 387, sse2.
+// 		Valid values are sse2 (default), softfloat.
 // 	GOMIPS
 // 		For GOARCH=mips{,le}, whether to use floating point instructions.
 // 		Valid values are hardfloat (default), softfloat.
@@ -1839,6 +1932,8 @@
 // 		If module-aware mode is disabled, GOMOD will be the empty string.
 // 	GOTOOLDIR
 // 		The directory where the go tools (compile, cover, doc, etc...) are installed.
+// 	GOVERSION
+// 		The version of the installed Go tree, as reported by runtime.Version.
 //
 //
 // File types
@@ -1894,21 +1989,23 @@
 // 	require new/thing/v2 v2.3.4
 // 	exclude old/thing v1.2.3
 // 	replace bad/thing v1.4.5 => good/thing v1.4.5
+// 	retract v1.5.6
 //
 // The verbs are
 // 	module, to define the module path;
 // 	go, to set the expected language version;
 // 	require, to require a particular module at a given version or later;
-// 	exclude, to exclude a particular module version from use; and
+// 	exclude, to exclude a particular module version from use;
-// 	replace, to replace a module version with a different module version.
+// 	replace, to replace a module version with a different module version; and
+// 	retract, to indicate a previously released version should not be used.
 // Exclude and replace apply only in the main module's go.mod and are ignored
-// in dependencies.  See https://research.swtch.com/vgo-mvs for details.
+// in dependencies.  See https://golang.org/ref/mod for details.
 //
 // The leading verb can be factored out of adjacent lines to create a block,
 // like in Go imports:
 //
 // 	require (
-// 		new/thing v2.3.4
+// 		new/thing/v2 v2.3.4
 // 		old/thing v1.2.3
 // 	)
 //
@@ -2146,6 +2243,10 @@
 //
 // The -insecure flag permits fetching from repositories and resolving
 // custom domains using insecure schemes such as HTTP. Use with caution.
+// This flag is deprecated and will be removed in a future version of go.
+// The GOINSECURE environment variable should be used instead, since it
+// provides control over which packages may be retrieved using an insecure
+// scheme. See 'go help environment' for details.
 //
 // The -t flag instructs get to also download the packages required to build
 // the tests for the specified packages.
@@ -2556,72 +2657,63 @@
 //
 // Maintaining module requirements
 //
-// The go.mod file is meant to be readable and editable by both
+// The go.mod file is meant to be readable and editable by both programmers and
-// programmers and tools. The go command itself automatically updates the go.mod file
+// tools. Most updates to dependencies can be performed using "go get" and
-// to maintain a standard formatting and the accuracy of require statements.
+// "go mod tidy". Other module-aware build commands may be invoked using the
+// -mod=mod flag to automatically add missing requirements and fix inconsistencies.
 //
-// Any go command that finds an unfamiliar import will look up the module
+// The "go get" command updates go.mod to change the module versions used in a
-// containing that import and add the latest version of that module
+// build. An upgrade of one module may imply upgrading others, and similarly a
-// to go.mod automatically. In most cases, therefore, it suffices to
+// downgrade of one module may imply downgrading others. The "go get" command
-// add an import to source code and run 'go build', 'go test', or even 'go list':
+// makes these implied changes as well. See "go help module-get".
-// as part of analyzing the package, the go command will discover
-// and resolve the import and update the go.mod file.
 //
-// Any go command can determine that a module requirement is
+// The "go mod" command provides other functionality for use in maintaining
-// missing and must be added, even when considering only a single
+// and understanding modules and go.mod files. See "go help mod", particularly
-// package from the module. On the other hand, determining that a module requirement
+// "go help mod tidy" and "go help mod edit".
-// is no longer necessary and can be deleted requires a full view of
-// all packages in the module, across all possible build configurations
-// (architectures, operating systems, build tags, and so on).
-// The 'go mod tidy' command builds that view and then
-// adds any missing module requirements and removes unnecessary ones.
 //
 // As part of maintaining the require statements in go.mod, the go command
 // tracks which ones provide packages imported directly by the current module
 // and which ones provide packages only used indirectly by other module
 // dependencies. Requirements needed only for indirect uses are marked with a
-// "// indirect" comment in the go.mod file. Indirect requirements are
+// "// indirect" comment in the go.mod file. Indirect requirements may be
 // automatically removed from the go.mod file once they are implied by other
 // direct requirements. Indirect requirements only arise when using modules
 // that fail to state some of their own dependencies or when explicitly
 // upgrading a module's dependencies ahead of its own stated requirements.
 //
-// Because of this automatic maintenance, the information in go.mod is an
+// The -mod build flag provides additional control over the updating and use of
-// up-to-date, readable description of the build.
+// go.mod for commands that build packages like "go build" and "go test".
 //
-// The 'go get' command updates go.mod to change the module versions used in a
+// If invoked with -mod=readonly (the default in most situations), the go command
-// build. An upgrade of one module may imply upgrading others, and similarly a
+// reports an error if a package named on the command line or an imported package
-// downgrade of one module may imply downgrading others. The 'go get' command
+// is not provided by any module in the build list computed from the main module's
-// makes these implied changes as well. If go.mod is edited directly, commands
+// requirements. The go command also reports an error if a module's checksum is
-// like 'go build' or 'go list' will assume that an upgrade is intended and
+// missing from go.sum (see Module downloading and verification). Either go.mod or
-// automatically make any implied upgrades and update go.mod to reflect them.
+// go.sum must be updated in these situations.
 //
-// The 'go mod' command provides other functionality for use in maintaining
+// If invoked with -mod=mod, the go command automatically updates go.mod and
-// and understanding modules and go.mod files. See 'go help mod'.
+// go.sum, fixing inconsistencies and adding missing requirements and checksums
-//
+// as needed. If the go command finds an unfamiliar import, it looks up the
-// The -mod build flag provides additional control over updating and use of go.mod.
+// module containing that import and adds a requirement for the latest version
-//
+// of that module to go.mod. In most cases, therefore, one may add an import to
-// If invoked with -mod=readonly, the go command is disallowed from the implicit
+// source code and run "go build", "go test", or even "go list" with -mod=mod:
-// automatic updating of go.mod described above. Instead, it fails when any changes
+// as part of analyzing the package, the go command will resolve the import and
-// to go.mod are needed. This setting is most useful to check that go.mod does
+// update the go.mod file.
-// not need updates, such as in a continuous integration and testing system.
-// The "go get" command remains permitted to update go.mod even with -mod=readonly,
-// and the "go mod" commands do not take the -mod flag (or any other build flags).
 //
 // If invoked with -mod=vendor, the go command loads packages from the main
 // module's vendor directory instead of downloading modules to and loading packages
 // from the module cache. The go command assumes the vendor directory holds
 // correct copies of dependencies, and it does not compute the set of required
 // module versions from go.mod files. However, the go command does check that
-// vendor/modules.txt (generated by 'go mod vendor') contains metadata consistent
+// vendor/modules.txt (generated by "go mod vendor") contains metadata consistent
 // with go.mod.
 //
-// If invoked with -mod=mod, the go command loads modules from the module cache
+// If the go command is not invoked with a -mod flag, and the vendor directory
-// even if there is a vendor directory present.
+// is present, and the "go" version in go.mod is 1.14 or higher, the go command
+// will act as if it were invoked with -mod=vendor. Otherwise, the -mod flag
+// defaults to -mod=readonly.
 //
-// If the go command is not invoked with a -mod flag and the vendor directory
+// Note that neither "go get" nor the "go mod" subcommands accept the -mod flag.
-// is present and the "go" version in go.mod is 1.14 or higher, the go command
-// will act as if it were invoked with -mod=vendor.
 //
 // Pseudo-versions
 //
@@ -2806,7 +2898,7 @@
 // followed by a pipe character, indicating it is safe to fall back on any error.
 //
 // The GOPRIVATE and GONOPROXY environment variables allow bypassing
-// the proxy for selected modules. See 'go help module-private' for details.
+// the proxy for selected modules. See 'go help private' for details.
 //
 // No matter the source of the modules, the go command checks downloads against
 // known checksums, to detect unexpected changes in the content of any specific
@@ -2926,52 +3018,7 @@
 // accepted, at the cost of giving up the security guarantee of verified repeatable
 // downloads for all modules. A better way to bypass the checksum database
 // for specific modules is to use the GOPRIVATE or GONOSUMDB environment
-// variables. See 'go help module-private' for details.
+// variables. See 'go help private' for details.
-//
-// The 'go env -w' command (see 'go help env') can be used to set these variables
-// for future go command invocations.
-//
-//
-// Module configuration for non-public modules
-//
-// The go command defaults to downloading modules from the public Go module
-// mirror at proxy.golang.org. It also defaults to validating downloaded modules,
-// regardless of source, against the public Go checksum database at sum.golang.org.
-// These defaults work well for publicly available source code.
-//
-// The GOPRIVATE environment variable controls which modules the go command
-// considers to be private (not available publicly) and should therefore not use the
-// proxy or checksum database. The variable is a comma-separated list of
-// glob patterns (in the syntax of Go's path.Match) of module path prefixes.
-// For example,
-//
-// 	GOPRIVATE=*.corp.example.com,rsc.io/private
-//
-// causes the go command to treat as private any module with a path prefix
-// matching either pattern, including git.corp.example.com/xyzzy, rsc.io/private,
-// and rsc.io/private/quux.
-//
-// The GOPRIVATE environment variable may be used by other tools as well to
-// identify non-public modules. For example, an editor could use GOPRIVATE
-// to decide whether to hyperlink a package import to a godoc.org page.
-//
-// For fine-grained control over module download and validation, the GONOPROXY
-// and GONOSUMDB environment variables accept the same kind of glob list
-// and override GOPRIVATE for the specific decision of whether to use the proxy
-// and checksum database, respectively.
-//
-// For example, if a company ran a module proxy serving private modules,
-// users would configure go using:
-//
-// 	GOPRIVATE=*.corp.example.com
-// 	GOPROXY=proxy.example.com
-// 	GONOPROXY=none
-//
-// This would tell the go command and other tools that modules beginning with
-// a corp.example.com subdomain are private but that the company proxy should
-// be used for downloading both public and private modules, because
-// GONOPROXY has been set to a pattern that won't match any modules,
-// overriding GOPRIVATE.
 //
 // The 'go env -w' command (see 'go help env') can be used to set these variables
 // for future go command invocations.
@@ -3061,6 +3108,56 @@
 // by the go tool, as are directories named "testdata".
 //
 //
+// Configuration for downloading non-public code
+//
+// The go command defaults to downloading modules from the public Go module
+// mirror at proxy.golang.org. It also defaults to validating downloaded modules,
+// regardless of source, against the public Go checksum database at sum.golang.org.
+// These defaults work well for publicly available source code.
+//
+// The GOPRIVATE environment variable controls which modules the go command
+// considers to be private (not available publicly) and should therefore not use the
+// proxy or checksum database. The variable is a comma-separated list of
+// glob patterns (in the syntax of Go's path.Match) of module path prefixes.
+// For example,
+//
+// 	GOPRIVATE=*.corp.example.com,rsc.io/private
+//
+// causes the go command to treat as private any module with a path prefix
+// matching either pattern, including git.corp.example.com/xyzzy, rsc.io/private,
+// and rsc.io/private/quux.
+//
+// The GOPRIVATE environment variable may be used by other tools as well to
+// identify non-public modules. For example, an editor could use GOPRIVATE
+// to decide whether to hyperlink a package import to a godoc.org page.
+//
+// For fine-grained control over module download and validation, the GONOPROXY
+// and GONOSUMDB environment variables accept the same kind of glob list
+// and override GOPRIVATE for the specific decision of whether to use the proxy
+// and checksum database, respectively.
+//
+// For example, if a company ran a module proxy serving private modules,
+// users would configure go using:
+//
+// 	GOPRIVATE=*.corp.example.com
+// 	GOPROXY=proxy.example.com
+// 	GONOPROXY=none
+//
+// This would tell the go command and other tools that modules beginning with
+// a corp.example.com subdomain are private but that the company proxy should
+// be used for downloading both public and private modules, because
+// GONOPROXY has been set to a pattern that won't match any modules,
+// overriding GOPRIVATE.
+//
+// The GOPRIVATE variable is also used to define the "public" and "private"
+// patterns for the GOVCS variable; see 'go help vcs'. For that usage,
+// GOPRIVATE applies even in GOPATH mode. In that case, it matches import paths
+// instead of module paths.
+//
+// The 'go env -w' command (see 'go help env') can be used to set these variables
+// for future go command invocations.
+//
+//
 // Testing flags
 //
 // The 'go test' command takes both flags that apply to 'go test' itself
@@ -3353,4 +3450,77 @@
 // See the documentation of the testing package for more information.
 //
 //
+// Controlling version control with GOVCS
+//
+// The 'go get' command can run version control commands like git
+// to download imported code. This functionality is critical to the decentralized
+// Go package ecosystem, in which code can be imported from any server,
+// but it is also a potential security problem, if a malicious server finds a
+// way to cause the invoked version control command to run unintended code.
+//
+// To balance the functionality and security concerns, the 'go get' command
+// by default will only use git and hg to download code from public servers.
+// But it will use any known version control system (bzr, fossil, git, hg, svn)
+// to download code from private servers, defined as those hosting packages
+// matching the GOPRIVATE variable (see 'go help private'). The rationale behind
+// allowing only Git and Mercurial is that these two systems have had the most
+// attention to issues of being run as clients of untrusted servers. In contrast,
+// Bazaar, Fossil, and Subversion have primarily been used in trusted,
+// authenticated environments and are not as well scrutinized as attack surfaces.
+//
+// The version control command restrictions only apply when using direct version
+// control access to download code. When downloading modules from a proxy,
+// 'go get' uses the proxy protocol instead, which is always permitted.
+// By default, the 'go get' command uses the Go module mirror (proxy.golang.org)
+// for public packages and only falls back to version control for private
+// packages or when the mirror refuses to serve a public package (typically for
+// legal reasons). Therefore, clients can still access public code served from
+// Bazaar, Fossil, or Subversion repositories by default, because those downloads
+// use the Go module mirror, which takes on the security risk of running the
+// version control commands, using a custom sandbox.
+//
+// The GOVCS variable can be used to change the allowed version control systems
+// for specific packages (identified by a module or import path).
+// The GOVCS variable applies both when using modules and when using GOPATH.
+// When using modules, the patterns match against the module path.
+// When using GOPATH, the patterns match against the import path
+// corresponding to the root of the version control repository.
+//
+// The general form of the GOVCS setting is a comma-separated list of
+// pattern:vcslist rules. The pattern is a glob pattern that must match
+// one or more leading elements of the module or import path. The vcslist
+// is a pipe-separated list of allowed version control commands, or "all"
+// to allow use of any known command, or "off" to allow nothing.
+// The earliest matching pattern in the list applies, even if later patterns
+// might also match.
+//
+// For example, consider:
+//
+// 	GOVCS=github.com:git,evil.com:off,*:git|hg
+//
+// With this setting, code with an module or import path beginning with
+// github.com/ can only use git; paths on evil.com cannot use any version
+// control command, and all other paths (* matches everything) can use
+// only git or hg.
+//
+// The special patterns "public" and "private" match public and private
+// module or import paths. A path is private if it matches the GOPRIVATE
+// variable; otherwise it is public.
+//
+// If no rules in the GOVCS variable match a particular module or import path,
+// the 'go get' command applies its default rule, which can now be summarized
+// in GOVCS notation as 'public:git|hg,private:all'.
+//
+// To allow unfettered use of any version control system for any package, use:
+//
+// 	GOVCS=*:all
+//
+// To disable all use of version control, use:
+//
+// 	GOVCS=*:off
+//
+// The 'go env -w' command (see 'go help env') can be used to set the GOVCS
+// variable for future go command invocations.
+//
+//
 package main

libgo/go/cmd/go/go_test.go

@@ -9,13 +9,14 @@ import (
 	"debug/elf"
 	"debug/macho"
 	"debug/pe"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"go/format"
 	"internal/race"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"log"
 	"os"
 	"os/exec"
@@ -30,77 +31,42 @@ import (
 	"cmd/go/internal/cache"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/robustio"
+	"cmd/go/internal/work"
 	"cmd/internal/sys"
 )
 
+func init() {
+	// GOVCS defaults to public:git|hg,private:all,
+	// which breaks many tests here - they can't use non-git, non-hg VCS at all!
+	// Change to fully permissive.
+	// The tests of the GOVCS setting itself are in ../../testdata/script/govcs.txt.
+	os.Setenv("GOVCS", "*:all")
+}
+
 var (
-	canRun  = true  // whether we can run go or ./testgo
 	canRace = false // whether we can run the race detector
 	canCgo  = false // whether we can use cgo
 	canMSan = false // whether we can run the memory sanitizer
-
-	exeSuffix string // ".exe" on Windows
-
-	skipExternal = false // skip external tests
 )
 
+var exeSuffix string = func() string {
+	if runtime.GOOS == "windows" {
+		return ".exe"
+	}
+	return ""
+}()
+
 func tooSlow(t *testing.T) {
 	if testing.Short() {
 		// In -short mode; skip test, except run it on the {darwin,linux,windows}/amd64 builders.
 		if testenv.Builder() != "" && runtime.GOARCH == "amd64" && (runtime.GOOS == "linux" || runtime.GOOS == "darwin" || runtime.GOOS == "windows") {
 			return
 		}
+		t.Helper()
 		t.Skip("skipping test in -short mode")
 	}
 }
 
-func init() {
-	switch runtime.GOOS {
-	case "android", "js":
-		canRun = false
-	case "darwin":
-		switch runtime.GOARCH {
-		case "arm64":
-			canRun = false
-		}
-	case "linux":
-		switch runtime.GOARCH {
-		case "arm":
-			// many linux/arm machines are too slow to run
-			// the full set of external tests.
-			skipExternal = true
-		case "mips", "mipsle", "mips64", "mips64le":
-			// Also slow.
-			skipExternal = true
-			if testenv.Builder() != "" {
-				// On the builders, skip the cmd/go
-				// tests. They're too slow and already
-				// covered by other ports. There's
-				// nothing os/arch specific in the
-				// tests.
-				canRun = false
-			}
-		}
-	case "freebsd":
-		switch runtime.GOARCH {
-		case "arm":
-			// many freebsd/arm machines are too slow to run
-			// the full set of external tests.
-			skipExternal = true
-			canRun = false
-		}
-	case "plan9":
-		switch runtime.GOARCH {
-		case "arm":
-			// many plan9/arm machines are too slow to run
-			// the full set of external tests.
-			skipExternal = true
-		}
-	case "windows":
-		exeSuffix = ".exe"
-	}
-}
-
 // testGOROOT is the GOROOT to use when running testgo, a cmd/go binary
 // build from this process's current GOROOT, but run from a different
 // (temp) directory.
@@ -134,7 +100,7 @@ func TestMain(m *testing.M) {
 
 	// Run with a temporary TMPDIR to check that the tests don't
 	// leave anything behind.
-	topTmpdir, err := ioutil.TempDir("", "cmd-go-test-")
+	topTmpdir, err := os.MkdirTemp("", "cmd-go-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -143,7 +109,7 @@ func TestMain(m *testing.M) {
 	}
 	os.Setenv(tempEnvName(), topTmpdir)
 
-	dir, err := ioutil.TempDir(topTmpdir, "tmpdir")
+	dir, err := os.MkdirTemp(topTmpdir, "tmpdir")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -153,7 +119,7 @@ func TestMain(m *testing.M) {
 	}
 
 	testGOCACHE = cache.DefaultDir()
-	if canRun {
+	if testenv.HasGoBuild() {
 		testBin = filepath.Join(testTmpDir, "testbin")
 		if err := os.Mkdir(testBin, 0777); err != nil {
 			log.Fatal(err)
@@ -224,7 +190,7 @@ func TestMain(m *testing.M) {
 		cmd.Stderr = new(strings.Builder)
 		if out, err := cmd.Output(); err != nil {
 			fmt.Fprintf(os.Stderr, "running testgo failed: %v\n%s", err, cmd.Stderr)
-			canRun = false
+			os.Exit(2)
 		} else {
 			canCgo, err = strconv.ParseBool(strings.TrimSpace(string(out)))
 			if err != nil {
@@ -324,10 +290,7 @@ func skipIfGccgo(t *testing.T, msg string) {
 func testgo(t *testing.T) *testgoData {
 	t.Helper()
 	testenv.MustHaveGoBuild(t)
-
+	testenv.SkipIfShortAndSlow(t)
-	if skipExternal {
-		t.Skipf("skipping external tests on %s/%s", runtime.GOOS, runtime.GOARCH)
-	}
 
 	return &testgoData{t: t}
 }
@@ -416,9 +379,6 @@ func (tg *testgoData) goTool() string {
 // returning exit status.
 func (tg *testgoData) doRun(args []string) error {
 	tg.t.Helper()
-	if !canRun {
-		panic("testgoData.doRun called but canRun false")
-	}
 	if tg.inParallel {
 		for _, arg := range args {
 			if strings.HasPrefix(arg, "testdata") || strings.HasPrefix(arg, "./testdata") {
@@ -656,7 +616,7 @@ func (tg *testgoData) makeTempdir() {
 	tg.t.Helper()
 	if tg.tempdir == "" {
 		var err error
-		tg.tempdir, err = ioutil.TempDir("", "gotest")
+		tg.tempdir, err = os.MkdirTemp("", "gotest")
 		tg.must(err)
 	}
 }
@@ -673,7 +633,7 @@ func (tg *testgoData) tempFile(path, contents string) {
 			bytes = formatted
 		}
 	}
-	tg.must(ioutil.WriteFile(filepath.Join(tg.tempdir, path), bytes, 0644))
+	tg.must(os.WriteFile(filepath.Join(tg.tempdir, path), bytes, 0644))
 }
 
 // tempDir adds a temporary directory for a run of testgo.
@@ -814,7 +774,7 @@ func (tg *testgoData) cleanup() {
 func removeAll(dir string) error {
 	// module cache has 0444 directories;
 	// make them writable in order to remove content.
-	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+	filepath.WalkDir(dir, func(path string, info fs.DirEntry, err error) error {
 		// chmod not only directories, but also things that we couldn't even stat
 		// due to permission errors: they may also be unreadable directories.
 		if err != nil || info.IsDir() {
@@ -860,8 +820,8 @@ func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
 	} {
 		srcdir := filepath.Join(testGOROOT, copydir)
 		tg.tempDir(filepath.Join("goroot", copydir))
-		err := filepath.Walk(srcdir,
+		err := filepath.WalkDir(srcdir,
-			func(path string, info os.FileInfo, err error) error {
+			func(path string, info fs.DirEntry, err error) error {
 				if err != nil {
 					return err
 				}
@@ -873,13 +833,13 @@ func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
 					return err
 				}
 				dest := filepath.Join("goroot", copydir, srcrel)
-				data, err := ioutil.ReadFile(path)
+				data, err := os.ReadFile(path)
 				if err != nil {
 					return err
 				}
 				tg.tempFile(dest, string(data))
-				if err := os.Chmod(tg.path(dest), info.Mode()|0200); err != nil {
+				if strings.Contains(copydir, filepath.Join("pkg", "tool")) {
-					return err
+					os.Chmod(tg.path(dest), 0777)
 				}
 				return nil
 			})
@@ -890,18 +850,18 @@ func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
 	tg.setenv("GOROOT", tg.path("goroot"))
 
 	addVar := func(name string, idx int) (restore func()) {
-		data, err := ioutil.ReadFile(name)
+		data, err := os.ReadFile(name)
 		if err != nil {
 			t.Fatal(err)
 		}
 		old := data
 		data = append(data, fmt.Sprintf("var DummyUnusedVar%d bool\n", idx)...)
-		if err := ioutil.WriteFile(name, append(data, '\n'), 0666); err != nil {
+		if err := os.WriteFile(name, append(data, '\n'), 0666); err != nil {
 			t.Fatal(err)
 		}
 		tg.sleep()
 		return func() {
-			if err := ioutil.WriteFile(name, old, 0666); err != nil {
+			if err := os.WriteFile(name, old, 0666); err != nil {
 				t.Fatal(err)
 			}
 		}
@@ -1237,6 +1197,18 @@ func TestGoListExport(t *testing.T) {
 	if _, err := os.Stat(file); err != nil {
 		t.Fatalf("cannot find .Export result %s: %v", file, err)
 	}
+
+	tg.run("list", "-export", "-f", "{{.BuildID}}", "strings")
+	buildID := strings.TrimSpace(tg.stdout.String())
+	if buildID == "" {
+		t.Fatalf(".BuildID with -export was empty")
+	}
+
+	tg.run("tool", "buildid", file)
+	toolBuildID := strings.TrimSpace(tg.stdout.String())
+	if buildID != toolBuildID {
+		t.Fatalf(".BuildID with -export %q disagrees with 'go tool buildid' %q", buildID, toolBuildID)
+	}
 }
 
 // Issue 4096. Validate the output of unsuccessful go install foo/quxx.
@@ -1394,6 +1366,30 @@ func TestLdflagsArgumentsWithSpacesIssue3941(t *testing.T) {
 	tg.grepStderr("^hello world", `ldflags -X "main.extern=hello world"' failed`)
 }
 
+func TestLdFlagsLongArgumentsIssue42295(t *testing.T) {
+	// Test the extremely long command line arguments that contain '\n' characters
+	// get encoded and passed correctly.
+	skipIfGccgo(t, "gccgo does not support -ldflags -X")
+	tooSlow(t)
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.tempFile("main.go", `package main
+		var extern string
+		func main() {
+			print(extern)
+		}`)
+	testStr := "test test test test test \n\\ "
+	var buf bytes.Buffer
+	for buf.Len() < work.ArgLengthForResponseFile+1 {
+		buf.WriteString(testStr)
+	}
+	tg.run("run", "-ldflags", fmt.Sprintf(`-X "main.extern=%s"`, buf.String()), tg.path("main.go"))
+	if tg.stderr.String() != buf.String() {
+		t.Errorf("strings differ")
+	}
+}
+
 func TestGoTestDashCDashOControlsBinaryLocation(t *testing.T) {
 	skipIfGccgo(t, "gccgo has no standard packages")
 	tooSlow(t)
@@ -1914,6 +1910,18 @@ func TestGoEnv(t *testing.T) {
 	tg.grepStdout("gcc", "CC not found")
 	tg.run("env", "GOGCCFLAGS")
 	tg.grepStdout("-ffaster", "CC arguments not found")
+
+	tg.run("env", "GOVERSION")
+	envVersion := strings.TrimSpace(tg.stdout.String())
+
+	tg.run("version")
+	cmdVersion := strings.TrimSpace(tg.stdout.String())
+
+	// If 'go version' is "go version <version> <goos>/<goarch>", then
+	// 'go env GOVERSION' is just "<version>".
+	if cmdVersion == envVersion || !strings.Contains(cmdVersion, envVersion) {
+		t.Fatalf("'go env GOVERSION' %q should be a shorter substring of 'go version' %q", envVersion, cmdVersion)
+	}
 }
 
 const (
@@ -2019,7 +2027,7 @@ func main() {
 	tg.run("build", "-o", exe, "p")
 }
 
-func copyFile(src, dst string, perm os.FileMode) error {
+func copyFile(src, dst string, perm fs.FileMode) error {
 	sf, err := os.Open(src)
 	if err != nil {
 		return err
@@ -2058,7 +2066,7 @@ func TestBuildmodePIE(t *testing.T) {
 
 	platform := fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH)
 	switch platform {
-	case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/s390x",
+	case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/riscv64", "linux/s390x",
 		"android/amd64", "android/arm", "android/arm64", "android/386",
 		"freebsd/amd64",
 		"windows/386", "windows/amd64", "windows/arm":
@@ -2166,6 +2174,38 @@ func testBuildmodePIE(t *testing.T, useCgo, setBuildmodeToPIE bool) {
 		if (dc & pe.IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE) == 0 {
 			t.Error("IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE flag is not set")
 		}
+		if useCgo {
+			// Test that only one symbol is exported (#40795).
+			// PIE binaries don´t require .edata section but unfortunately
+			// binutils doesn´t generate a .reloc section unless there is
+			// at least one symbol exported.
+			// See https://sourceware.org/bugzilla/show_bug.cgi?id=19011
+			section := f.Section(".edata")
+			if section == nil {
+				t.Fatalf(".edata section is not present")
+			}
+			// TODO: deduplicate this struct from cmd/link/internal/ld/pe.go
+			type IMAGE_EXPORT_DIRECTORY struct {
+				_                 [2]uint32
+				_                 [2]uint16
+				_                 [2]uint32
+				NumberOfFunctions uint32
+				NumberOfNames     uint32
+				_                 [3]uint32
+			}
+			var e IMAGE_EXPORT_DIRECTORY
+			if err := binary.Read(section.Open(), binary.LittleEndian, &e); err != nil {
+				t.Fatalf("binary.Read failed: %v", err)
+			}
+
+			// Only _cgo_dummy_export should be exported
+			if e.NumberOfFunctions != 1 {
+				t.Fatalf("got %d exported functions; want 1", e.NumberOfFunctions)
+			}
+			if e.NumberOfNames != 1 {
+				t.Fatalf("got %d exported names; want 1", e.NumberOfNames)
+			}
+		}
 	default:
 		panic("unreachable")
 	}
@@ -2658,7 +2698,7 @@ echo $* >>`+tg.path("pkg-config.out"))
 	tg.setenv("GOPATH", tg.path("."))
 	tg.setenv("PKG_CONFIG", tg.path("pkg-config.sh"))
 	tg.run("build", "x")
-	out, err := ioutil.ReadFile(tg.path("pkg-config.out"))
+	out, err := os.ReadFile(tg.path("pkg-config.out"))
 	tg.must(err)
 	out = bytes.TrimSpace(out)
 	want := "--cflags --static --static -- a a\n--libs --static --static -- a a"

libgo/go/cmd/go/go_windows_test.go

@@ -2,11 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package main
+package main_test
 
 import (
-	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -17,16 +15,18 @@ import (
 )
 
 func TestAbsolutePath(t *testing.T) {
-	t.Parallel()
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
 
-	tmp, err := ioutil.TempDir("", "TestAbsolutePath")
+	tmp, err := os.MkdirTemp("", "TestAbsolutePath")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer robustio.RemoveAll(tmp)
 
 	file := filepath.Join(tmp, "a.go")
-	err = ioutil.WriteFile(file, []byte{}, 0644)
+	err = os.WriteFile(file, []byte{}, 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -38,7 +38,7 @@ func TestAbsolutePath(t *testing.T) {
 
 	noVolume := file[len(filepath.VolumeName(file)):]
 	wrongPath := filepath.Join(dir, noVolume)
-	cmd := exec.Command(testenv.GoToolPath(t), "build", noVolume)
+	cmd := exec.Command(tg.goTool(), "build", noVolume)
 	cmd.Dir = dir
 	output, err := cmd.CombinedOutput()
 	if err == nil {

libgo/go/cmd/go/help_test.go

@@ -6,7 +6,7 @@ package main_test
 
 import (
 	"bytes"
-	"io/ioutil"
+	"os"
 	"testing"
 
 	"cmd/go/internal/help"
@@ -23,7 +23,7 @@ func TestDocsUpToDate(t *testing.T) {
 	buf := new(bytes.Buffer)
 	// Match the command in mkalldocs.sh that generates alldocs.go.
 	help.Help(buf, []string{"documentation"})
-	data, err := ioutil.ReadFile("alldocs.go")
+	data, err := os.ReadFile("alldocs.go")
 	if err != nil {
 		t.Fatalf("error reading alldocs.go: %v", err)
 	}

libgo/go/cmd/go/init_test.go

@@ -7,6 +7,7 @@ package main_test
 import (
 	"internal/testenv"
 	"os/exec"
+	"sync/atomic"
 	"testing"
 )
 
@@ -15,20 +16,27 @@ import (
 // the benchmark if any changes were done.
 func BenchmarkExecGoEnv(b *testing.B) {
 	testenv.MustHaveExec(b)
-	b.StopTimer()
 	gotool, err := testenv.GoTool()
 	if err != nil {
 		b.Fatal(err)
 	}
-	for i := 0; i < b.N; i++ {
-		cmd := exec.Command(gotool, "env", "GOARCH")
 
-		b.StartTimer()
+	// We collect extra metrics.
-		err := cmd.Run()
+	var n, userTime, systemTime int64
-		b.StopTimer()
 
-		if err != nil {
+	b.ResetTimer()
-			b.Fatal(err)
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			cmd := exec.Command(gotool, "env", "GOARCH")
+
+			if err := cmd.Run(); err != nil {
+				b.Fatal(err)
+			}
+			atomic.AddInt64(&n, 1)
+			atomic.AddInt64(&userTime, int64(cmd.ProcessState.UserTime()))
+			atomic.AddInt64(&systemTime, int64(cmd.ProcessState.SystemTime()))
 		}
-	}
+	})
+	b.ReportMetric(float64(userTime)/float64(n), "user-ns/op")
+	b.ReportMetric(float64(systemTime)/float64(n), "sys-ns/op")
 }

libgo/go/cmd/go/internal/auth/netrc.go

@@ -5,7 +5,6 @@
 package auth
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -99,7 +98,7 @@ func readNetrc() {
 		return
 	}
 
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		if !os.IsNotExist(err) {
 			netrcErr = err

libgo/go/cmd/go/internal/base/base.go

@@ -7,6 +7,7 @@
 package base
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"log"
@@ -24,7 +25,7 @@ import (
 type Command struct {
 	// Run runs the command.
 	// The args are the arguments after the command name.
-	Run func(cmd *Command, args []string)
+	Run func(ctx context.Context, cmd *Command, args []string)
 
 	// UsageLine is the one-line usage message.
 	// The words between "go" and the first flag or argument in the line are taken to be the command name.
@@ -55,6 +56,20 @@ var Go = &Command{
 	// Commands initialized in package main
 }
 
+// hasFlag reports whether a command or any of its subcommands contain the given
+// flag.
+func hasFlag(c *Command, name string) bool {
+	if f := c.Flag.Lookup(name); f != nil {
+		return true
+	}
+	for _, sub := range c.Commands {
+		if hasFlag(sub, name) {
+			return true
+		}
+	}
+	return false
+}
+
 // LongName returns the command's long name: all the words in the usage line between "go" and a flag or argument,
 func (c *Command) LongName() string {
 	name := c.UsageLine

libgo/go/cmd/go/internal/base/flag.go

@@ -8,6 +8,7 @@ import (
 	"flag"
 
 	"cmd/go/internal/cfg"
+	"cmd/go/internal/fsys"
 	"cmd/go/internal/str"
 )
 
@@ -28,13 +29,43 @@ func (v *StringsFlag) String() string {
 	return "<StringsFlag>"
 }
 
+// explicitStringFlag is like a regular string flag, but it also tracks whether
+// the string was set explicitly to a non-empty value.
+type explicitStringFlag struct {
+	value    *string
+	explicit *bool
+}
+
+func (f explicitStringFlag) String() string {
+	if f.value == nil {
+		return ""
+	}
+	return *f.value
+}
+
+func (f explicitStringFlag) Set(v string) error {
+	*f.value = v
+	if v != "" {
+		*f.explicit = true
+	}
+	return nil
+}
+
 // AddBuildFlagsNX adds the -n and -x build flags to the flag set.
 func AddBuildFlagsNX(flags *flag.FlagSet) {
 	flags.BoolVar(&cfg.BuildN, "n", false, "")
 	flags.BoolVar(&cfg.BuildX, "x", false, "")
 }
 
-// AddLoadFlags adds the -mod build flag to the flag set.
+// AddModFlag adds the -mod build flag to the flag set.
-func AddLoadFlags(flags *flag.FlagSet) {
+func AddModFlag(flags *flag.FlagSet) {
-	flags.StringVar(&cfg.BuildMod, "mod", "", "")
+	flags.Var(explicitStringFlag{value: &cfg.BuildMod, explicit: &cfg.BuildModExplicit}, "mod", "")
+}
+
+// AddModCommonFlags adds the module-related flags common to build commands
+// and 'go mod' subcommands.
+func AddModCommonFlags(flags *flag.FlagSet) {
+	flags.BoolVar(&cfg.ModCacheRW, "modcacherw", false, "")
+	flags.StringVar(&cfg.ModFile, "modfile", "", "")
+	flags.StringVar(&fsys.OverlayFile, "overlay", "", "")
 }

libgo/go/cmd/go/internal/base/goflags.go

@@ -13,15 +13,7 @@ import (
 	"cmd/go/internal/cfg"
 )
 
-var (
+var goflags []string // cached $GOFLAGS list; can be -x or --x form
-	goflags   []string                // cached $GOFLAGS list; can be -x or --x form
-	knownFlag = make(map[string]bool) // flags allowed to appear in $GOFLAGS; no leading dashes
-)
-
-// AddKnownFlag adds name to the list of known flags for use in $GOFLAGS.
-func AddKnownFlag(name string) {
-	knownFlag[name] = true
-}
 
 // GOFLAGS returns the flags from $GOFLAGS.
 // The list can be assumed to contain one string per flag,
@@ -38,22 +30,12 @@ func InitGOFLAGS() {
 		return
 	}
 
-	// Build list of all flags for all commands.
+	goflags = strings.Fields(cfg.Getenv("GOFLAGS"))
-	// If no command has that flag, then we report the problem.
+	if len(goflags) == 0 {
-	// This catches typos while still letting users record flags in GOFLAGS
+		// nothing to do; avoid work on later InitGOFLAGS call
-	// that only apply to a subset of go commands.
+		goflags = []string{}
-	// Commands using CustomFlags can report their flag names
+		return
-	// by calling AddKnownFlag instead.
-	var walkFlags func(*Command)
-	walkFlags = func(cmd *Command) {
-		for _, sub := range cmd.Commands {
-			walkFlags(sub)
-		}
-		cmd.Flag.VisitAll(func(f *flag.Flag) {
-			knownFlag[f.Name] = true
-		})
 	}
-	walkFlags(Go)
 
 	// Ignore bad flag in go env and go bug, because
 	// they are what people reach for when debugging
@@ -61,11 +43,6 @@ func InitGOFLAGS() {
 	// (Both will show the GOFLAGS setting if let succeed.)
 	hideErrors := cfg.CmdName == "env" || cfg.CmdName == "bug"
 
-	goflags = strings.Fields(cfg.Getenv("GOFLAGS"))
-	if goflags == nil {
-		goflags = []string{} // avoid work on later InitGOFLAGS call
-	}
-
 	// Each of the words returned by strings.Fields must be its own flag.
 	// To set flag arguments use -x=value instead of -x value.
 	// For boolean flags, -x is fine instead of -x=true.
@@ -85,7 +62,7 @@ func InitGOFLAGS() {
 		if i := strings.Index(name, "="); i >= 0 {
 			name = name[:i]
 		}
-		if !knownFlag[name] {
+		if !hasFlag(Go, name) {
 			if hideErrors {
 				continue
 			}
@@ -115,7 +92,11 @@ func SetFromGOFLAGS(flags *flag.FlagSet) {
 	}
 	for _, goflag := range goflags {
 		name, value, hasValue := goflag, "", false
-		if i := strings.Index(goflag, "="); i >= 0 {
+		// Ignore invalid flags like '=' or '=value'.
+		// If it is not reported in InitGOFlags it means we don't want to report it.
+		if i := strings.Index(goflag, "="); i == 0 {
+			continue
+		} else if i > 0 {
 			name, value, hasValue = goflag[:i], goflag[i+1:], true
 		}
 		if strings.HasPrefix(name, "--") {

libgo/go/cmd/go/internal/base/signal.go

@@ -15,7 +15,7 @@ var Interrupted = make(chan struct{})
 
 // processSignals setups signal handler.
 func processSignals() {
-	sig := make(chan os.Signal)
+	sig := make(chan os.Signal, 1)
 	signal.Notify(sig, signalsToIgnore...)
 	go func() {
 		<-sig

libgo/go/cmd/go/internal/bug/bug.go

@@ -7,9 +7,9 @@ package bug
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	urlpkg "net/url"
 	"os"
 	"os/exec"
@@ -37,7 +37,7 @@ func init() {
 	CmdBug.Flag.BoolVar(&cfg.BuildV, "v", false, "")
 }
 
-func runBug(cmd *base.Command, args []string) {
+func runBug(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) > 0 {
 		base.Fatalf("go bug: bug takes no arguments")
 	}
@@ -104,7 +104,7 @@ func printGoDetails(w io.Writer) {
 
 func printOSDetails(w io.Writer) {
 	switch runtime.GOOS {
-	case "darwin":
+	case "darwin", "ios":
 		printCmdOut(w, "uname -v: ", "uname", "-v")
 		printCmdOut(w, "", "sw_vers")
 	case "linux":
@@ -116,7 +116,7 @@ func printOSDetails(w io.Writer) {
 	case "illumos", "solaris":
 		// Be sure to use the OS-supplied uname, in "/usr/bin":
 		printCmdOut(w, "uname -srv: ", "/usr/bin/uname", "-srv")
-		out, err := ioutil.ReadFile("/etc/release")
+		out, err := os.ReadFile("/etc/release")
 		if err == nil {
 			fmt.Fprintf(w, "/etc/release: %s\n", out)
 		} else {
@@ -176,7 +176,7 @@ func printGlibcVersion(w io.Writer) {
 	src := []byte(`int main() {}`)
 	srcfile := filepath.Join(tempdir, "go-bug.c")
 	outfile := filepath.Join(tempdir, "go-bug")
-	err := ioutil.WriteFile(srcfile, src, 0644)
+	err := os.WriteFile(srcfile, src, 0644)
 	if err != nil {
 		return
 	}

libgo/go/cmd/go/internal/cache/cache.go

@@ -12,7 +12,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -54,7 +54,7 @@ func Open(dir string) (*Cache, error) {
 		return nil, err
 	}
 	if !info.IsDir() {
-		return nil, &os.PathError{Op: "open", Path: dir, Err: fmt.Errorf("not a directory")}
+		return nil, &fs.PathError{Op: "open", Path: dir, Err: fmt.Errorf("not a directory")}
 	}
 	for i := 0; i < 256; i++ {
 		name := filepath.Join(dir, fmt.Sprintf("%02x", i))
@@ -238,7 +238,7 @@ func (c *Cache) GetBytes(id ActionID) ([]byte, Entry, error) {
 	if err != nil {
 		return nil, entry, err
 	}
-	data, _ := ioutil.ReadFile(c.OutputFile(entry.OutputID))
+	data, _ := os.ReadFile(c.OutputFile(entry.OutputID))
 	if sha256.Sum256(data) != entry.OutputID {
 		return nil, entry, &entryNotFoundError{Err: errors.New("bad checksum")}
 	}
@@ -377,7 +377,7 @@ func (c *Cache) putIndexEntry(id ActionID, out OutputID, size int64, allowVerify
 		// Truncate the file only *after* writing it.
 		// (This should be a no-op, but truncate just in case of previous corruption.)
 		//
-		// This differs from ioutil.WriteFile, which truncates to 0 *before* writing
+		// This differs from os.WriteFile, which truncates to 0 *before* writing
 		// via os.O_TRUNC. Truncating only after writing ensures that a second write
 		// of the same content to the same file is idempotent, and does not — even
 		// temporarily! — undo the effect of the first write.

libgo/go/cmd/go/internal/cache/cache_test.go

@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -20,7 +19,7 @@ func init() {
 }
 
 func TestBasic(t *testing.T) {
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -65,7 +64,7 @@ func TestBasic(t *testing.T) {
 }
 
 func TestGrowth(t *testing.T) {
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -118,7 +117,7 @@ func TestVerifyPanic(t *testing.T) {
 		t.Fatal("initEnv did not set verify")
 	}
 
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -151,7 +150,7 @@ func dummyID(x int) [HashSize]byte {
 }
 
 func TestCacheTrim(t *testing.T) {
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -207,7 +206,7 @@ func TestCacheTrim(t *testing.T) {
 		t.Fatal(err)
 	}
 	c.OutputFile(entry.OutputID)
-	data, err := ioutil.ReadFile(filepath.Join(dir, "trim.txt"))
+	data, err := os.ReadFile(filepath.Join(dir, "trim.txt"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -220,7 +219,7 @@ func TestCacheTrim(t *testing.T) {
 		t.Fatal(err)
 	}
 	c.OutputFile(entry.OutputID)
-	data2, err := ioutil.ReadFile(filepath.Join(dir, "trim.txt"))
+	data2, err := os.ReadFile(filepath.Join(dir, "trim.txt"))
 	if err != nil {
 		t.Fatal(err)
 	}

libgo/go/cmd/go/internal/cache/default.go

@@ -6,7 +6,6 @@ package cache
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sync"
@@ -49,7 +48,7 @@ func initDefaultCache() {
 	}
 	if _, err := os.Stat(filepath.Join(dir, "README")); err != nil {
 		// Best effort.
-		ioutil.WriteFile(filepath.Join(dir, "README"), []byte(cacheREADME), 0666)
+		os.WriteFile(filepath.Join(dir, "README"), []byte(cacheREADME), 0666)
 	}
 
 	c, err := Open(dir)

libgo/go/cmd/go/internal/cache/hash_test.go

@@ -6,7 +6,6 @@ package cache
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"testing"
 )
@@ -28,7 +27,7 @@ func TestHash(t *testing.T) {
 }
 
 func TestHashFile(t *testing.T) {
-	f, err := ioutil.TempFile("", "cmd-go-test-")
+	f, err := os.CreateTemp("", "cmd-go-test-")
 	if err != nil {
 		t.Fatal(err)
 	}

libgo/go/cmd/go/internal/cfg/cfg.go

@@ -11,13 +11,15 @@ import (
 	"fmt"
 	"go/build"
 	"internal/cfg"
-	"io/ioutil"
+	"io"
 	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"sync"
 
+	"cmd/go/internal/fsys"
+
 	"cmd/internal/objabi"
 )
 
@@ -27,7 +29,8 @@ var (
 	BuildBuildmode         string // -buildmode flag
 	BuildContext           = defaultContext()
 	BuildMod               string             // -mod flag
-	BuildModReason         string             // reason -mod flag is set, if set by default
+	BuildModExplicit       bool               // whether -mod was set explicitly
+	BuildModReason         string             // reason -mod was set, if set by default
 	BuildI                 bool               // -i flag
 	BuildLinkshared        bool               // -linkshared flag
 	BuildMSan              bool               // -msan flag
@@ -48,9 +51,12 @@ var (
 	ModCacheRW bool   // -modcacherw flag
 	ModFile    string // -modfile flag
 
+	Insecure bool // -insecure flag
+
 	CmdName string // "build", "install", "list", "mod tidy", etc.
 
 	DebugActiongraph string // -debug-actiongraph flag (undocumented, unstable)
+	DebugTrace       string // -debug-trace flag
 )
 
 func defaultContext() build.Context {
@@ -100,6 +106,15 @@ func defaultContext() build.Context {
 		// Nothing to do here.
 	}
 
+	ctxt.OpenFile = func(path string) (io.ReadCloser, error) {
+		return fsys.Open(path)
+	}
+	ctxt.ReadDir = fsys.ReadDir
+	ctxt.IsDir = func(path string) bool {
+		isDir, err := fsys.IsDir(path)
+		return err == nil && isDir
+	}
+
 	return ctxt
 }
 
@@ -171,7 +186,7 @@ func initEnvCache() {
 	if file == "" {
 		return
 	}
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil {
 		return
 	}
@@ -252,6 +267,7 @@ var (
 	GONOPROXY  = envOr("GONOPROXY", GOPRIVATE)
 	GONOSUMDB  = envOr("GONOSUMDB", GOPRIVATE)
 	GOINSECURE = Getenv("GOINSECURE")
+	GOVCS      = Getenv("GOVCS")
 )
 
 var SumdbDir = gopathDir("pkg/sumdb")

libgo/go/cmd/go/internal/clean/clean.go

@@ -6,8 +6,9 @@
 package clean
 
 import (
+	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -105,7 +106,7 @@ func init() {
 	work.AddBuildFlags(CmdClean, work.DefaultBuildFlags)
 }
 
-func runClean(cmd *base.Command, args []string) {
+func runClean(ctx context.Context, cmd *base.Command, args []string) {
 	// golang.org/issue/29925: only load packages before cleaning if
 	// either the flags and arguments explicitly imply a package,
 	// or no other target (such as a cache) was requested to be cleaned.
@@ -116,7 +117,7 @@ func runClean(cmd *base.Command, args []string) {
 	}
 
 	if cleanPkg {
-		for _, pkg := range load.PackagesAndErrors(args) {
+		for _, pkg := range load.PackagesAndErrors(ctx, args) {
 			clean(pkg)
 		}
 	}
@@ -171,7 +172,7 @@ func runClean(cmd *base.Command, args []string) {
 			f, err := lockedfile.Edit(filepath.Join(dir, "testexpire.txt"))
 			if err == nil {
 				now := time.Now().UnixNano()
-				buf, _ := ioutil.ReadAll(f)
+				buf, _ := io.ReadAll(f)
 				prev, _ := strconv.ParseInt(strings.TrimSpace(string(buf)), 10, 64)
 				if now > prev {
 					if err = f.Truncate(0); err == nil {
@@ -242,7 +243,7 @@ func clean(p *load.Package) {
 		base.Errorf("%v", p.Error)
 		return
 	}
-	dirs, err := ioutil.ReadDir(p.Dir)
+	dirs, err := os.ReadDir(p.Dir)
 	if err != nil {
 		base.Errorf("go clean %s: %v", p.Dir, err)
 		return
@@ -274,6 +275,8 @@ func clean(p *load.Package) {
 		allRemove = append(allRemove,
 			elem,
 			elem+".exe",
+			p.DefaultExecName(),
+			p.DefaultExecName()+".exe",
 		)
 	}
 
@@ -281,16 +284,28 @@ func clean(p *load.Package) {
 	allRemove = append(allRemove,
 		elem+".test",
 		elem+".test.exe",
+		p.DefaultExecName()+".test",
+		p.DefaultExecName()+".test.exe",
 	)
 
-	// Remove a potential executable for each .go file in the directory that
+	// Remove a potential executable, test executable for each .go file in the directory that
 	// is not part of the directory's package.
 	for _, dir := range dirs {
 		name := dir.Name()
 		if packageFile[name] {
 			continue
 		}
-		if !dir.IsDir() && strings.HasSuffix(name, ".go") {
+
+		if dir.IsDir() {
+			continue
+		}
+
+		if strings.HasSuffix(name, "_test.go") {
+			base := name[:len(name)-len("_test.go")]
+			allRemove = append(allRemove, base+".test", base+".test.exe")
+		}
+
+		if strings.HasSuffix(name, ".go") {
 			// TODO(adg,rsc): check that this .go file is actually
 			// in "package main", and therefore capable of building
 			// to an executable file.

libgo/go/cmd/go/internal/doc/doc.go

@@ -8,6 +8,7 @@ package doc
 import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
+	"context"
 )
 
 var CmdDoc = &base.Command{
@@ -129,6 +130,6 @@ Flags:
 `,
 }
 
-func runDoc(cmd *base.Command, args []string) {
+func runDoc(ctx context.Context, cmd *base.Command, args []string) {
 	base.Run(cfg.BuildToolexec, base.Tool("doc"), args)
 }

libgo/go/cmd/go/internal/envcmd/env.go

@@ -6,10 +6,10 @@
 package envcmd
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"go/build"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -20,6 +20,7 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cache"
 	"cmd/go/internal/cfg"
+	"cmd/go/internal/fsys"
 	"cmd/go/internal/load"
 	"cmd/go/internal/modload"
 	"cmd/go/internal/work"
@@ -62,9 +63,6 @@ var (
 )
 
 func MkEnv() []cfg.EnvVar {
-	var b work.Builder
-	b.Init()
-
 	envFile, _ := cfg.EnvFile()
 	env := []cfg.EnvVar{
 		{Name: "GO111MODULE", Value: cfg.Getenv("GO111MODULE")},
@@ -88,6 +86,8 @@ func MkEnv() []cfg.EnvVar {
 		{Name: "GOSUMDB", Value: cfg.GOSUMDB},
 		{Name: "GOTMPDIR", Value: cfg.Getenv("GOTMPDIR")},
 		{Name: "GOTOOLDIR", Value: base.ToolDir},
+		{Name: "GOVCS", Value: cfg.GOVCS},
+		{Name: "GOVERSION", Value: runtime.Version()},
 	}
 
 	if work.GccgoBin != "" {
@@ -186,7 +186,7 @@ func argKey(arg string) string {
 	return arg[:i]
 }
 
-func runEnv(cmd *base.Command, args []string) {
+func runEnv(ctx context.Context, cmd *base.Command, args []string) {
 	if *envJson && *envU {
 		base.Fatalf("go env: cannot use -json with -u")
 	}
@@ -199,12 +199,26 @@ func runEnv(cmd *base.Command, args []string) {
 	env := cfg.CmdEnv
 	env = append(env, ExtraEnvVars()...)
 
+	if err := fsys.Init(base.Cwd); err != nil {
+		base.Fatalf("go: %v", err)
+	}
+
 	// Do we need to call ExtraEnvVarsCostly, which is a bit expensive?
-	// Only if we're listing all environment variables ("go env")
+	needCostly := false
-	// or the variables being requested are in the extra list.
+	if *envU || *envW {
-	needCostly := true
+		// We're overwriting or removing default settings,
-	if len(args) > 0 {
+		// so it doesn't really matter what the existing settings are.
+		//
+		// Moreover, we haven't validated the new settings yet, so it is
+		// important that we NOT perform any actions based on them,
+		// such as initializing the builder to compute other variables.
+	} else if len(args) == 0 {
+		// We're listing all environment variables ("go env"),
+		// including the expensive ones.
+		needCostly = true
+	} else {
 		needCostly = false
+	checkCostly:
 		for _, arg := range args {
 			switch argKey(arg) {
 			case "CGO_CFLAGS",
@@ -215,6 +229,7 @@ func runEnv(cmd *base.Command, args []string) {
 				"PKG_CONFIG",
 				"GOGCCFLAGS":
 				needCostly = true
+				break checkCostly
 			}
 		}
 	}
@@ -266,6 +281,13 @@ func runEnv(cmd *base.Command, args []string) {
 			}
 		}
 
+		gotmp, okGOTMP := add["GOTMPDIR"]
+		if okGOTMP {
+			if !filepath.IsAbs(gotmp) && gotmp != "" {
+				base.Fatalf("go env -w: GOTMPDIR must be an absolute path")
+			}
+		}
+
 		updateEnvFile(add, nil)
 		return
 	}
@@ -377,7 +399,7 @@ func getOrigEnv(key string) string {
 
 func checkEnvWrite(key, val string) error {
 	switch key {
-	case "GOEXE", "GOGCCFLAGS", "GOHOSTARCH", "GOHOSTOS", "GOMOD", "GOTOOLDIR":
+	case "GOEXE", "GOGCCFLAGS", "GOHOSTARCH", "GOHOSTOS", "GOMOD", "GOTOOLDIR", "GOVERSION":
 		return fmt.Errorf("%s cannot be modified", key)
 	case "GOENV":
 		return fmt.Errorf("%s can only be set using the OS environment", key)
@@ -405,6 +427,11 @@ func checkEnvWrite(key, val string) error {
 		if !filepath.IsAbs(val) && val != "" {
 			return fmt.Errorf("GOPATH entry is relative; must be absolute path: %q", val)
 		}
+	// Make sure CC and CXX are absolute paths
+	case "CC", "CXX":
+		if !filepath.IsAbs(val) && val != "" && val != filepath.Base(val) {
+			return fmt.Errorf("%s entry is relative; must be absolute path: %q", key, val)
+		}
 	}
 
 	if !utf8.ValidString(val) {
@@ -424,7 +451,7 @@ func updateEnvFile(add map[string]string, del map[string]bool) {
 	if file == "" {
 		base.Fatalf("go env: cannot find go env config: %v", err)
 	}
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil && (!os.IsNotExist(err) || len(add) == 0) {
 		base.Fatalf("go env: reading go env config: %v", err)
 	}
@@ -478,11 +505,11 @@ func updateEnvFile(add map[string]string, del map[string]bool) {
 	}
 
 	data = []byte(strings.Join(lines, ""))
-	err = ioutil.WriteFile(file, data, 0666)
+	err = os.WriteFile(file, data, 0666)
 	if err != nil {
 		// Try creating directory.
 		os.MkdirAll(filepath.Dir(file), 0777)
-		err = ioutil.WriteFile(file, data, 0666)
+		err = os.WriteFile(file, data, 0666)
 		if err != nil {
 			base.Fatalf("go env: writing go env config: %v", err)
 		}
@@ -499,7 +526,10 @@ func lineToKey(line string) string {
 }
 
 // sortKeyValues sorts a sequence of lines by key.
-// It differs from sort.Strings in that GO386= sorts after GO=.
+// It differs from sort.Strings in that keys which are GOx where x is an ASCII
+// character smaller than = sort after GO=.
+// (There are no such keys currently. It used to matter for GO386 which was
+// removed in Go 1.16.)
 func sortKeyValues(lines []string) {
 	sort.Slice(lines, func(i, j int) bool {
 		return lineToKey(lines[i]) < lineToKey(lines[j])

libgo/go/cmd/go/internal/fix/fix.go

@@ -11,6 +11,7 @@ import (
 	"cmd/go/internal/load"
 	"cmd/go/internal/modload"
 	"cmd/go/internal/str"
+	"context"
 	"fmt"
 	"os"
 )
@@ -31,9 +32,21 @@ See also: go fmt, go vet.
 	`,
 }
 
-func runFix(cmd *base.Command, args []string) {
+func runFix(ctx context.Context, cmd *base.Command, args []string) {
+	pkgs := load.PackagesAndErrors(ctx, args)
+	w := 0
+	for _, pkg := range pkgs {
+		if pkg.Error != nil {
+			base.Errorf("%v", pkg.Error)
+			continue
+		}
+		pkgs[w] = pkg
+		w++
+	}
+	pkgs = pkgs[:w]
+
 	printed := false
-	for _, pkg := range load.Packages(args) {
+	for _, pkg := range pkgs {
 		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
 			if !printed {
 				fmt.Fprintf(os.Stderr, "go: not fixing packages in dependency modules\n")

libgo/go/cmd/go/internal/fmtcmd/fmt.go

@@ -6,6 +6,7 @@
 package fmtcmd
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"os"
@@ -22,7 +23,8 @@ import (
 
 func init() {
 	base.AddBuildFlagsNX(&CmdFmt.Flag)
-	base.AddLoadFlags(&CmdFmt.Flag)
+	base.AddModFlag(&CmdFmt.Flag)
+	base.AddModCommonFlags(&CmdFmt.Flag)
 }
 
 var CmdFmt = &base.Command{
@@ -48,7 +50,7 @@ See also: go fix, go vet.
 	`,
 }
 
-func runFmt(cmd *base.Command, args []string) {
+func runFmt(ctx context.Context, cmd *base.Command, args []string) {
 	printed := false
 	gofmt := gofmtPath()
 	procs := runtime.GOMAXPROCS(0)
@@ -63,7 +65,7 @@ func runFmt(cmd *base.Command, args []string) {
 			}
 		}()
 	}
-	for _, pkg := range load.PackagesAndErrors(args) {
+	for _, pkg := range load.PackagesAndErrors(ctx, args) {
 		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
 			if !printed {
 				fmt.Fprintf(os.Stderr, "go: not formatting packages in dependency modules\n")

libgo/go/cmd/go/internal/fsys/fsys.go

@@ -0,0 +1,689 @@
+// Package fsys is an abstraction for reading files that
+// allows for virtual overlays on top of the files on disk.
+package fsys
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+	"time"
+)
+
+// OverlayFile is the path to a text file in the OverlayJSON format.
+// It is the value of the -overlay flag.
+var OverlayFile string
+
+// OverlayJSON is the format overlay files are expected to be in.
+// The Replace map maps from overlaid paths to replacement paths:
+// the Go command will forward all reads trying to open
+// each overlaid path to its replacement path, or consider the overlaid
+// path not to exist if the replacement path is empty.
+type OverlayJSON struct {
+	Replace map[string]string
+}
+
+type node struct {
+	actualFilePath string           // empty if a directory
+	children       map[string]*node // path element → file or directory
+}
+
+func (n *node) isDir() bool {
+	return n.actualFilePath == "" && n.children != nil
+}
+
+func (n *node) isDeleted() bool {
+	return n.actualFilePath == "" && n.children == nil
+}
+
+// TODO(matloob): encapsulate these in an io/fs-like interface
+var overlay map[string]*node // path -> file or directory node
+var cwd string               // copy of base.Cwd to avoid dependency
+
+// Canonicalize a path for looking it up in the overlay.
+// Important: filepath.Join(cwd, path) doesn't always produce
+// the correct absolute path if path is relative, because on
+// Windows producing the correct absolute path requires making
+// a syscall. So this should only be used when looking up paths
+// in the overlay, or canonicalizing the paths in the overlay.
+func canonicalize(path string) string {
+	if path == "" {
+		return ""
+	}
+	if filepath.IsAbs(path) {
+		return filepath.Clean(path)
+	}
+
+	if v := filepath.VolumeName(cwd); v != "" && path[0] == filepath.Separator {
+		// On Windows filepath.Join(cwd, path) doesn't always work. In general
+		// filepath.Abs needs to make a syscall on Windows. Elsewhere in cmd/go
+		// use filepath.Join(cwd, path), but cmd/go specifically supports Windows
+		// paths that start with "\" which implies the path is relative to the
+		// volume of the working directory. See golang.org/issue/8130.
+		return filepath.Join(v, path)
+	}
+
+	// Make the path absolute.
+	return filepath.Join(cwd, path)
+}
+
+// Init initializes the overlay, if one is being used.
+func Init(wd string) error {
+	if overlay != nil {
+		// already initialized
+		return nil
+	}
+
+	cwd = wd
+
+	if OverlayFile == "" {
+		return nil
+	}
+
+	b, err := os.ReadFile(OverlayFile)
+	if err != nil {
+		return fmt.Errorf("reading overlay file: %v", err)
+	}
+
+	var overlayJSON OverlayJSON
+	if err := json.Unmarshal(b, &overlayJSON); err != nil {
+		return fmt.Errorf("parsing overlay JSON: %v", err)
+	}
+
+	return initFromJSON(overlayJSON)
+}
+
+func initFromJSON(overlayJSON OverlayJSON) error {
+	// Canonicalize the paths in in the overlay map.
+	// Use reverseCanonicalized to check for collisions:
+	// no two 'from' paths should canonicalize to the same path.
+	overlay = make(map[string]*node)
+	reverseCanonicalized := make(map[string]string) // inverse of canonicalize operation, to check for duplicates
+	// Build a table of file and directory nodes from the replacement map.
+
+	// Remove any potential non-determinism from iterating over map by sorting it.
+	replaceFrom := make([]string, 0, len(overlayJSON.Replace))
+	for k := range overlayJSON.Replace {
+		replaceFrom = append(replaceFrom, k)
+	}
+	sort.Strings(replaceFrom)
+
+	for _, from := range replaceFrom {
+		to := overlayJSON.Replace[from]
+		// Canonicalize paths and check for a collision.
+		if from == "" {
+			return fmt.Errorf("empty string key in overlay file Replace map")
+		}
+		cfrom := canonicalize(from)
+		if to != "" {
+			// Don't canonicalize "", meaning to delete a file, because then it will turn into ".".
+			to = canonicalize(to)
+		}
+		if otherFrom, seen := reverseCanonicalized[cfrom]; seen {
+			return fmt.Errorf(
+				"paths %q and %q both canonicalize to %q in overlay file Replace map", otherFrom, from, cfrom)
+		}
+		reverseCanonicalized[cfrom] = from
+		from = cfrom
+
+		// Create node for overlaid file.
+		dir, base := filepath.Dir(from), filepath.Base(from)
+		if n, ok := overlay[from]; ok {
+			// All 'from' paths in the overlay are file paths. Since the from paths
+			// are in a map, they are unique, so if the node already exists we added
+			// it below when we create parent directory nodes. That is, that
+			// both a file and a path to one of its parent directories exist as keys
+			// in the Replace map.
+			//
+			// This only applies if the overlay directory has any files or directories
+			// in it: placeholder directories that only contain deleted files don't
+			// count. They are safe to be overwritten with actual files.
+			for _, f := range n.children {
+				if !f.isDeleted() {
+					return fmt.Errorf("invalid overlay: path %v is used as both file and directory", from)
+				}
+			}
+		}
+		overlay[from] = &node{actualFilePath: to}
+
+		// Add parent directory nodes to overlay structure.
+		childNode := overlay[from]
+		for {
+			dirNode := overlay[dir]
+			if dirNode == nil || dirNode.isDeleted() {
+				dirNode = &node{children: make(map[string]*node)}
+				overlay[dir] = dirNode
+			}
+			if childNode.isDeleted() {
+				// Only create one parent for a deleted file:
+				// the directory only conditionally exists if
+				// there are any non-deleted children, so
+				// we don't create their parents.
+				if dirNode.isDir() {
+					dirNode.children[base] = childNode
+				}
+				break
+			}
+			if !dirNode.isDir() {
+				// This path already exists as a file, so it can't be a parent
+				// directory. See comment at error above.
+				return fmt.Errorf("invalid overlay: path %v is used as both file and directory", dir)
+			}
+			dirNode.children[base] = childNode
+			parent := filepath.Dir(dir)
+			if parent == dir {
+				break // reached the top; there is no parent
+			}
+			dir, base = parent, filepath.Base(dir)
+			childNode = dirNode
+		}
+	}
+
+	return nil
+}
+
+// IsDir returns true if path is a directory on disk or in the
+// overlay.
+func IsDir(path string) (bool, error) {
+	path = canonicalize(path)
+
+	if _, ok := parentIsOverlayFile(path); ok {
+		return false, nil
+	}
+
+	if n, ok := overlay[path]; ok {
+		return n.isDir(), nil
+	}
+
+	fi, err := os.Stat(path)
+	if err != nil {
+		return false, err
+	}
+
+	return fi.IsDir(), nil
+}
+
+// parentIsOverlayFile returns whether name or any of
+// its parents are files in the overlay, and the first parent found,
+// including name itself, that's a file in the overlay.
+func parentIsOverlayFile(name string) (string, bool) {
+	if overlay != nil {
+		// Check if name can't possibly be a directory because
+		// it or one of its parents is overlaid with a file.
+		// TODO(matloob): Maybe save this to avoid doing it every time?
+		prefix := name
+		for {
+			node := overlay[prefix]
+			if node != nil && !node.isDir() {
+				return prefix, true
+			}
+			parent := filepath.Dir(prefix)
+			if parent == prefix {
+				break
+			}
+			prefix = parent
+		}
+	}
+
+	return "", false
+}
+
+// errNotDir is used to communicate from ReadDir to IsDirWithGoFiles
+// that the argument is not a directory, so that IsDirWithGoFiles doesn't
+// return an error.
+var errNotDir = errors.New("not a directory")
+
+// readDir reads a dir on disk, returning an error that is errNotDir if the dir is not a directory.
+// Unfortunately, the error returned by ioutil.ReadDir if dir is not a directory
+// can vary depending on the OS (Linux, Mac, Windows return ENOTDIR; BSD returns EINVAL).
+func readDir(dir string) ([]fs.FileInfo, error) {
+	fis, err := ioutil.ReadDir(dir)
+	if err == nil {
+		return fis, nil
+	}
+
+	if os.IsNotExist(err) {
+		return nil, err
+	}
+	if dirfi, staterr := os.Stat(dir); staterr == nil && !dirfi.IsDir() {
+		return nil, &fs.PathError{Op: "ReadDir", Path: dir, Err: errNotDir}
+	}
+	return nil, err
+}
+
+// ReadDir provides a slice of fs.FileInfo entries corresponding
+// to the overlaid files in the directory.
+func ReadDir(dir string) ([]fs.FileInfo, error) {
+	dir = canonicalize(dir)
+	if _, ok := parentIsOverlayFile(dir); ok {
+		return nil, &fs.PathError{Op: "ReadDir", Path: dir, Err: errNotDir}
+	}
+
+	dirNode := overlay[dir]
+	if dirNode == nil {
+		return readDir(dir)
+	}
+	if dirNode.isDeleted() {
+		return nil, &fs.PathError{Op: "ReadDir", Path: dir, Err: fs.ErrNotExist}
+	}
+	diskfis, err := readDir(dir)
+	if err != nil && !os.IsNotExist(err) && !errors.Is(err, errNotDir) {
+		return nil, err
+	}
+
+	// Stat files in overlay to make composite list of fileinfos
+	files := make(map[string]fs.FileInfo)
+	for _, f := range diskfis {
+		files[f.Name()] = f
+	}
+	for name, to := range dirNode.children {
+		switch {
+		case to.isDir():
+			files[name] = fakeDir(name)
+		case to.isDeleted():
+			delete(files, name)
+		default:
+			// This is a regular file.
+			f, err := os.Lstat(to.actualFilePath)
+			if err != nil {
+				files[name] = missingFile(name)
+				continue
+			} else if f.IsDir() {
+				return nil, fmt.Errorf("for overlay of %q to %q: overlay Replace entries can't point to dirctories",
+					filepath.Join(dir, name), to.actualFilePath)
+			}
+			// Add a fileinfo for the overlaid file, so that it has
+			// the original file's name, but the overlaid file's metadata.
+			files[name] = fakeFile{name, f}
+		}
+	}
+	sortedFiles := diskfis[:0]
+	for _, f := range files {
+		sortedFiles = append(sortedFiles, f)
+	}
+	sort.Slice(sortedFiles, func(i, j int) bool { return sortedFiles[i].Name() < sortedFiles[j].Name() })
+	return sortedFiles, nil
+}
+
+// OverlayPath returns the path to the overlaid contents of the
+// file, the empty string if the overlay deletes the file, or path
+// itself if the file is not in the overlay, the file is a directory
+// in the overlay, or there is no overlay.
+// It returns true if the path is overlaid with a regular file
+// or deleted, and false otherwise.
+func OverlayPath(path string) (string, bool) {
+	if p, ok := overlay[canonicalize(path)]; ok && !p.isDir() {
+		return p.actualFilePath, ok
+	}
+
+	return path, false
+}
+
+// Open opens the file at or overlaid on the given path.
+func Open(path string) (*os.File, error) {
+	return OpenFile(path, os.O_RDONLY, 0)
+}
+
+// OpenFile opens the file at or overlaid on the given path with the flag and perm.
+func OpenFile(path string, flag int, perm os.FileMode) (*os.File, error) {
+	cpath := canonicalize(path)
+	if node, ok := overlay[cpath]; ok {
+		// Opening a file in the overlay.
+		if node.isDir() {
+			return nil, &fs.PathError{Op: "OpenFile", Path: path, Err: errors.New("fsys.OpenFile doesn't support opening directories yet")}
+		}
+		// We can't open overlaid paths for write.
+		if perm != os.FileMode(os.O_RDONLY) {
+			return nil, &fs.PathError{Op: "OpenFile", Path: path, Err: errors.New("overlaid files can't be opened for write")}
+		}
+		return os.OpenFile(node.actualFilePath, flag, perm)
+	}
+	if parent, ok := parentIsOverlayFile(filepath.Dir(cpath)); ok {
+		// The file is deleted explicitly in the Replace map,
+		// or implicitly because one of its parent directories was
+		// replaced by a file.
+		return nil, &fs.PathError{
+			Op:   "Open",
+			Path: path,
+			Err:  fmt.Errorf("file %s does not exist: parent directory %s is replaced by a file in overlay", path, parent),
+		}
+	}
+	return os.OpenFile(cpath, flag, perm)
+}
+
+// IsDirWithGoFiles reports whether dir is a directory containing Go files
+// either on disk or in the overlay.
+func IsDirWithGoFiles(dir string) (bool, error) {
+	fis, err := ReadDir(dir)
+	if os.IsNotExist(err) || errors.Is(err, errNotDir) {
+		return false, nil
+	}
+	if err != nil {
+		return false, err
+	}
+
+	var firstErr error
+	for _, fi := range fis {
+		if fi.IsDir() {
+			continue
+		}
+
+		// TODO(matloob): this enforces that the "from" in the map
+		// has a .go suffix, but the actual destination file
+		// doesn't need to have a .go suffix. Is this okay with the
+		// compiler?
+		if !strings.HasSuffix(fi.Name(), ".go") {
+			continue
+		}
+		if fi.Mode().IsRegular() {
+			return true, nil
+		}
+
+		// fi is the result of an Lstat, so it doesn't follow symlinks.
+		// But it's okay if the file is a symlink pointing to a regular
+		// file, so use os.Stat to follow symlinks and check that.
+		actualFilePath, _ := OverlayPath(filepath.Join(dir, fi.Name()))
+		fi, err := os.Stat(actualFilePath)
+		if err == nil && fi.Mode().IsRegular() {
+			return true, nil
+		}
+		if err != nil && firstErr == nil {
+			firstErr = err
+		}
+	}
+
+	// No go files found in directory.
+	return false, firstErr
+}
+
+// walk recursively descends path, calling walkFn. Copied, with some
+// modifications from path/filepath.walk.
+func walk(path string, info fs.FileInfo, walkFn filepath.WalkFunc) error {
+	if !info.IsDir() {
+		return walkFn(path, info, nil)
+	}
+
+	fis, readErr := ReadDir(path)
+	walkErr := walkFn(path, info, readErr)
+	// If readErr != nil, walk can't walk into this directory.
+	// walkErr != nil means walkFn want walk to skip this directory or stop walking.
+	// Therefore, if one of readErr and walkErr isn't nil, walk will return.
+	if readErr != nil || walkErr != nil {
+		// The caller's behavior is controlled by the return value, which is decided
+		// by walkFn. walkFn may ignore readErr and return nil.
+		// If walkFn returns SkipDir, it will be handled by the caller.
+		// So walk should return whatever walkFn returns.
+		return walkErr
+	}
+
+	for _, fi := range fis {
+		filename := filepath.Join(path, fi.Name())
+		if walkErr = walk(filename, fi, walkFn); walkErr != nil {
+			if !fi.IsDir() || walkErr != filepath.SkipDir {
+				return walkErr
+			}
+		}
+	}
+	return nil
+}
+
+// Walk walks the file tree rooted at root, calling walkFn for each file or
+// directory in the tree, including root.
+func Walk(root string, walkFn filepath.WalkFunc) error {
+	info, err := Lstat(root)
+	if err != nil {
+		err = walkFn(root, nil, err)
+	} else {
+		err = walk(root, info, walkFn)
+	}
+	if err == filepath.SkipDir {
+		return nil
+	}
+	return err
+}
+
+// lstat implements a version of os.Lstat that operates on the overlay filesystem.
+func Lstat(path string) (fs.FileInfo, error) {
+	return overlayStat(path, os.Lstat, "lstat")
+}
+
+// Stat implements a version of os.Stat that operates on the overlay filesystem.
+func Stat(path string) (fs.FileInfo, error) {
+	return overlayStat(path, os.Stat, "stat")
+}
+
+// overlayStat implements lstat or Stat (depending on whether os.Lstat or os.Stat is passed in).
+func overlayStat(path string, osStat func(string) (fs.FileInfo, error), opName string) (fs.FileInfo, error) {
+	cpath := canonicalize(path)
+
+	if _, ok := parentIsOverlayFile(filepath.Dir(cpath)); ok {
+		return nil, &fs.PathError{Op: opName, Path: cpath, Err: fs.ErrNotExist}
+	}
+
+	node, ok := overlay[cpath]
+	if !ok {
+		// The file or directory is not overlaid.
+		return osStat(path)
+	}
+
+	switch {
+	case node.isDeleted():
+		return nil, &fs.PathError{Op: "lstat", Path: cpath, Err: fs.ErrNotExist}
+	case node.isDir():
+		return fakeDir(filepath.Base(path)), nil
+	default:
+		fi, err := osStat(node.actualFilePath)
+		if err != nil {
+			return nil, err
+		}
+		return fakeFile{name: filepath.Base(path), real: fi}, nil
+	}
+}
+
+// fakeFile provides an fs.FileInfo implementation for an overlaid file,
+// so that the file has the name of the overlaid file, but takes all
+// other characteristics of the replacement file.
+type fakeFile struct {
+	name string
+	real fs.FileInfo
+}
+
+func (f fakeFile) Name() string       { return f.name }
+func (f fakeFile) Size() int64        { return f.real.Size() }
+func (f fakeFile) Mode() fs.FileMode  { return f.real.Mode() }
+func (f fakeFile) ModTime() time.Time { return f.real.ModTime() }
+func (f fakeFile) IsDir() bool        { return f.real.IsDir() }
+func (f fakeFile) Sys() interface{}   { return f.real.Sys() }
+
+// missingFile provides an fs.FileInfo for an overlaid file where the
+// destination file in the overlay doesn't exist. It returns zero values
+// for the fileInfo methods other than Name, set to the file's name, and Mode
+// set to ModeIrregular.
+type missingFile string
+
+func (f missingFile) Name() string       { return string(f) }
+func (f missingFile) Size() int64        { return 0 }
+func (f missingFile) Mode() fs.FileMode  { return fs.ModeIrregular }
+func (f missingFile) ModTime() time.Time { return time.Unix(0, 0) }
+func (f missingFile) IsDir() bool        { return false }
+func (f missingFile) Sys() interface{}   { return nil }
+
+// fakeDir provides an fs.FileInfo implementation for directories that are
+// implicitly created by overlaid files. Each directory in the
+// path of an overlaid file is considered to exist in the overlay filesystem.
+type fakeDir string
+
+func (f fakeDir) Name() string       { return string(f) }
+func (f fakeDir) Size() int64        { return 0 }
+func (f fakeDir) Mode() fs.FileMode  { return fs.ModeDir | 0500 }
+func (f fakeDir) ModTime() time.Time { return time.Unix(0, 0) }
+func (f fakeDir) IsDir() bool        { return true }
+func (f fakeDir) Sys() interface{}   { return nil }
+
+// Glob is like filepath.Glob but uses the overlay file system.
+func Glob(pattern string) (matches []string, err error) {
+	// Check pattern is well-formed.
+	if _, err := filepath.Match(pattern, ""); err != nil {
+		return nil, err
+	}
+	if !hasMeta(pattern) {
+		if _, err = Lstat(pattern); err != nil {
+			return nil, nil
+		}
+		return []string{pattern}, nil
+	}
+
+	dir, file := filepath.Split(pattern)
+	volumeLen := 0
+	if runtime.GOOS == "windows" {
+		volumeLen, dir = cleanGlobPathWindows(dir)
+	} else {
+		dir = cleanGlobPath(dir)
+	}
+
+	if !hasMeta(dir[volumeLen:]) {
+		return glob(dir, file, nil)
+	}
+
+	// Prevent infinite recursion. See issue 15879.
+	if dir == pattern {
+		return nil, filepath.ErrBadPattern
+	}
+
+	var m []string
+	m, err = Glob(dir)
+	if err != nil {
+		return
+	}
+	for _, d := range m {
+		matches, err = glob(d, file, matches)
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+// cleanGlobPath prepares path for glob matching.
+func cleanGlobPath(path string) string {
+	switch path {
+	case "":
+		return "."
+	case string(filepath.Separator):
+		// do nothing to the path
+		return path
+	default:
+		return path[0 : len(path)-1] // chop off trailing separator
+	}
+}
+
+func volumeNameLen(path string) int {
+	isSlash := func(c uint8) bool {
+		return c == '\\' || c == '/'
+	}
+	if len(path) < 2 {
+		return 0
+	}
+	// with drive letter
+	c := path[0]
+	if path[1] == ':' && ('a' <= c && c <= 'z' || 'A' <= c && c <= 'Z') {
+		return 2
+	}
+	// is it UNC? https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
+	if l := len(path); l >= 5 && isSlash(path[0]) && isSlash(path[1]) &&
+		!isSlash(path[2]) && path[2] != '.' {
+		// first, leading `\\` and next shouldn't be `\`. its server name.
+		for n := 3; n < l-1; n++ {
+			// second, next '\' shouldn't be repeated.
+			if isSlash(path[n]) {
+				n++
+				// third, following something characters. its share name.
+				if !isSlash(path[n]) {
+					if path[n] == '.' {
+						break
+					}
+					for ; n < l; n++ {
+						if isSlash(path[n]) {
+							break
+						}
+					}
+					return n
+				}
+				break
+			}
+		}
+	}
+	return 0
+}
+
+// cleanGlobPathWindows is windows version of cleanGlobPath.
+func cleanGlobPathWindows(path string) (prefixLen int, cleaned string) {
+	vollen := volumeNameLen(path)
+	switch {
+	case path == "":
+		return 0, "."
+	case vollen+1 == len(path) && os.IsPathSeparator(path[len(path)-1]): // /, \, C:\ and C:/
+		// do nothing to the path
+		return vollen + 1, path
+	case vollen == len(path) && len(path) == 2: // C:
+		return vollen, path + "." // convert C: into C:.
+	default:
+		if vollen >= len(path) {
+			vollen = len(path) - 1
+		}
+		return vollen, path[0 : len(path)-1] // chop off trailing separator
+	}
+}
+
+// glob searches for files matching pattern in the directory dir
+// and appends them to matches. If the directory cannot be
+// opened, it returns the existing matches. New matches are
+// added in lexicographical order.
+func glob(dir, pattern string, matches []string) (m []string, e error) {
+	m = matches
+	fi, err := Stat(dir)
+	if err != nil {
+		return // ignore I/O error
+	}
+	if !fi.IsDir() {
+		return // ignore I/O error
+	}
+
+	list, err := ReadDir(dir)
+	if err != nil {
+		return // ignore I/O error
+	}
+
+	var names []string
+	for _, info := range list {
+		names = append(names, info.Name())
+	}
+	sort.Strings(names)
+
+	for _, n := range names {
+		matched, err := filepath.Match(pattern, n)
+		if err != nil {
+			return m, err
+		}
+		if matched {
+			m = append(m, filepath.Join(dir, n))
+		}
+	}
+	return
+}
+
+// hasMeta reports whether path contains any of the magic characters
+// recognized by filepath.Match.
+func hasMeta(path string) bool {
+	magicChars := `*?[`
+	if runtime.GOOS != "windows" {
+		magicChars = `*?[\`
+	}
+	return strings.ContainsAny(path, magicChars)
+}

libgo/go/cmd/go/internal/generate/generate.go

@@ -8,11 +8,11 @@ package generate
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"fmt"
 	"go/parser"
 	"go/token"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -160,7 +160,7 @@ func init() {
 	CmdGenerate.Flag.StringVar(&generateRunFlag, "run", "", "")
 }
 
-func runGenerate(cmd *base.Command, args []string) {
+func runGenerate(ctx context.Context, cmd *base.Command, args []string) {
 	load.IgnoreImports = true
 
 	if generateRunFlag != "" {
@@ -175,7 +175,7 @@ func runGenerate(cmd *base.Command, args []string) {
 
 	// Even if the arguments are .go files, this loop suffices.
 	printed := false
-	for _, pkg := range load.PackagesAndErrors(args) {
+	for _, pkg := range load.PackagesAndErrors(ctx, args) {
 		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
 			if !printed {
 				fmt.Fprintf(os.Stderr, "go: not generating in packages in dependency modules\n")
@@ -200,7 +200,7 @@ func runGenerate(cmd *base.Command, args []string) {
 
 // generate runs the generation directives for a single file.
 func generate(absFile string) bool {
-	src, err := ioutil.ReadFile(absFile)
+	src, err := os.ReadFile(absFile)
 	if err != nil {
 		log.Fatalf("generate: %s", err)
 	}

libgo/go/cmd/go/internal/get/get.go

@@ -6,6 +6,7 @@
 package get
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -17,8 +18,11 @@ import (
 	"cmd/go/internal/load"
 	"cmd/go/internal/search"
 	"cmd/go/internal/str"
+	"cmd/go/internal/vcs"
 	"cmd/go/internal/web"
 	"cmd/go/internal/work"
+
+	"golang.org/x/mod/module"
 )
 
 var CmdGet = &base.Command{
@@ -41,6 +45,10 @@ before resolving dependencies or building the code.
 
 The -insecure flag permits fetching from repositories and resolving
 custom domains using insecure schemes such as HTTP. Use with caution.
+This flag is deprecated and will be removed in a future version of go.
+The GOINSECURE environment variable should be used instead, since it
+provides control over which packages may be retrieved using an insecure
+scheme. See 'go help environment' for details.
 
 The -t flag instructs get to also download the packages required to build
 the tests for the specified packages.
@@ -102,17 +110,15 @@ var (
 	getT   = CmdGet.Flag.Bool("t", false, "")
 	getU   = CmdGet.Flag.Bool("u", false, "")
 	getFix = CmdGet.Flag.Bool("fix", false, "")
-
-	Insecure bool
 )
 
 func init() {
 	work.AddBuildFlags(CmdGet, work.OmitModFlag|work.OmitModCommonFlags)
 	CmdGet.Run = runGet // break init loop
-	CmdGet.Flag.BoolVar(&Insecure, "insecure", Insecure, "")
+	CmdGet.Flag.BoolVar(&cfg.Insecure, "insecure", cfg.Insecure, "")
 }
 
-func runGet(cmd *base.Command, args []string) {
+func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	if cfg.ModulesEnabled {
 		// Should not happen: main.go should install the separate module-enabled get code.
 		base.Fatalf("go get: modules not implemented")
@@ -123,6 +129,9 @@ func runGet(cmd *base.Command, args []string) {
 	if *getF && !*getU {
 		base.Fatalf("go get: cannot use -f flag without -u")
 	}
+	if cfg.Insecure {
+		fmt.Fprintf(os.Stderr, "go get: -insecure flag is deprecated; see 'go help get' for details\n")
+	}
 
 	// Disable any prompting for passwords by Git.
 	// Only has an effect for 2.3.0 or later, but avoiding
@@ -171,17 +180,18 @@ func runGet(cmd *base.Command, args []string) {
 	// everything.
 	load.ClearPackageCache()
 
-	pkgs := load.PackagesForBuild(args)
+	pkgs := load.PackagesAndErrors(ctx, args)
+	load.CheckPackageErrors(pkgs)
 
 	// Phase 3. Install.
 	if *getD {
 		// Download only.
-		// Check delayed until now so that importPaths
+		// Check delayed until now so that downloadPaths
-		// and packagesForBuild have a chance to print errors.
+		// and CheckPackageErrors have a chance to print errors.
 		return
 	}
 
-	work.InstallPackages(args, pkgs)
+	work.InstallPackages(ctx, args, pkgs)
 }
 
 // downloadPaths prepares the list of paths to pass to download.
@@ -245,9 +255,9 @@ func download(arg string, parent *load.Package, stk *load.ImportStack, mode int)
 	load1 := func(path string, mode int) *load.Package {
 		if parent == nil {
 			mode := 0 // don't do module or vendor resolution
-			return load.LoadImport(path, base.Cwd, nil, stk, nil, mode)
+			return load.LoadImport(context.TODO(), path, base.Cwd, nil, stk, nil, mode)
 		}
-		return load.LoadImport(path, parent.Dir, parent, stk, nil, mode|load.ResolveModule)
+		return load.LoadImport(context.TODO(), path, parent.Dir, parent, stk, nil, mode|load.ResolveModule)
 	}
 
 	p := load1(arg, mode)
@@ -402,17 +412,12 @@ func download(arg string, parent *load.Package, stk *load.ImportStack, mode int)
 // to make the first copy of or update a copy of the given package.
 func downloadPackage(p *load.Package) error {
 	var (
-		vcs            *vcsCmd
+		vcsCmd         *vcs.Cmd
 		repo, rootPath string
 		err            error
 		blindRepo      bool // set if the repo has unusual configuration
 	)
 
-	security := web.SecureOnly
-	if Insecure {
-		security = web.Insecure
-	}
-
 	// p can be either a real package, or a pseudo-package whose “import path” is
 	// actually a wildcard pattern.
 	// Trim the path at the element containing the first wildcard,
@@ -426,22 +431,26 @@ func downloadPackage(p *load.Package) error {
 		}
 		importPrefix = importPrefix[:slash]
 	}
-	if err := CheckImportPath(importPrefix); err != nil {
+	if err := module.CheckImportPath(importPrefix); err != nil {
 		return fmt.Errorf("%s: invalid import path: %v", p.ImportPath, err)
 	}
+	security := web.SecureOnly
+	if cfg.Insecure || module.MatchPrefixPatterns(cfg.GOINSECURE, importPrefix) {
+		security = web.Insecure
+	}
 
 	if p.Internal.Build.SrcRoot != "" {
 		// Directory exists. Look for checkout along path to src.
-		vcs, rootPath, err = vcsFromDir(p.Dir, p.Internal.Build.SrcRoot)
+		vcsCmd, rootPath, err = vcs.FromDir(p.Dir, p.Internal.Build.SrcRoot)
 		if err != nil {
 			return err
 		}
 		repo = "<local>" // should be unused; make distinctive
 
 		// Double-check where it came from.
-		if *getU && vcs.remoteRepo != nil {
+		if *getU && vcsCmd.RemoteRepo != nil {
 			dir := filepath.Join(p.Internal.Build.SrcRoot, filepath.FromSlash(rootPath))
-			remote, err := vcs.remoteRepo(vcs, dir)
+			remote, err := vcsCmd.RemoteRepo(vcsCmd, dir)
 			if err != nil {
 				// Proceed anyway. The package is present; we likely just don't understand
 				// the repo configuration (e.g. unusual remote protocol).
@@ -449,10 +458,10 @@ func downloadPackage(p *load.Package) error {
 			}
 			repo = remote
 			if !*getF && err == nil {
-				if rr, err := RepoRootForImportPath(importPrefix, IgnoreMod, security); err == nil {
+				if rr, err := vcs.RepoRootForImportPath(importPrefix, vcs.IgnoreMod, security); err == nil {
 					repo := rr.Repo
-					if rr.vcs.resolveRepo != nil {
+					if rr.VCS.ResolveRepo != nil {
-						resolved, err := rr.vcs.resolveRepo(rr.vcs, dir, repo)
+						resolved, err := rr.VCS.ResolveRepo(rr.VCS, dir, repo)
 						if err == nil {
 							repo = resolved
 						}
@@ -466,13 +475,13 @@ func downloadPackage(p *load.Package) error {
 	} else {
 		// Analyze the import path to determine the version control system,
 		// repository, and the import path for the root of the repository.
-		rr, err := RepoRootForImportPath(importPrefix, IgnoreMod, security)
+		rr, err := vcs.RepoRootForImportPath(importPrefix, vcs.IgnoreMod, security)
 		if err != nil {
 			return err
 		}
-		vcs, repo, rootPath = rr.vcs, rr.Repo, rr.Root
+		vcsCmd, repo, rootPath = rr.VCS, rr.Repo, rr.Root
 	}
-	if !blindRepo && !vcs.isSecure(repo) && !Insecure {
+	if !blindRepo && !vcsCmd.IsSecure(repo) && security != web.Insecure {
 		return fmt.Errorf("cannot download, %v uses insecure protocol", repo)
 	}
 
@@ -495,7 +504,7 @@ func downloadPackage(p *load.Package) error {
 	}
 	root := filepath.Join(p.Internal.Build.SrcRoot, filepath.FromSlash(rootPath))
 
-	if err := checkNestedVCS(vcs, root, p.Internal.Build.SrcRoot); err != nil {
+	if err := vcs.CheckNested(vcsCmd, root, p.Internal.Build.SrcRoot); err != nil {
 		return err
 	}
 
@@ -511,7 +520,7 @@ func downloadPackage(p *load.Package) error {
 
 	// Check that this is an appropriate place for the repo to be checked out.
 	// The target directory must either not exist or have a repo checked out already.
-	meta := filepath.Join(root, "."+vcs.cmd)
+	meta := filepath.Join(root, "."+vcsCmd.Cmd)
 	if _, err := os.Stat(meta); err != nil {
 		// Metadata file or directory does not exist. Prepare to checkout new copy.
 		// Some version control tools require the target directory not to exist.
@@ -532,12 +541,12 @@ func downloadPackage(p *load.Package) error {
 			fmt.Fprintf(os.Stderr, "created GOPATH=%s; see 'go help gopath'\n", p.Internal.Build.Root)
 		}
 
-		if err = vcs.create(root, repo); err != nil {
+		if err = vcsCmd.Create(root, repo); err != nil {
 			return err
 		}
 	} else {
 		// Metadata directory does exist; download incremental updates.
-		if err = vcs.download(root); err != nil {
+		if err = vcsCmd.Download(root); err != nil {
 			return err
 		}
 	}
@@ -546,12 +555,12 @@ func downloadPackage(p *load.Package) error {
 		// Do not show tag sync in -n; it's noise more than anything,
 		// and since we're not running commands, no tag will be found.
 		// But avoid printing nothing.
-		fmt.Fprintf(os.Stderr, "# cd %s; %s sync/update\n", root, vcs.cmd)
+		fmt.Fprintf(os.Stderr, "# cd %s; %s sync/update\n", root, vcsCmd.Cmd)
 		return nil
 	}
 
 	// Select and sync to appropriate version of the repository.
-	tags, err := vcs.tags(root)
+	tags, err := vcsCmd.Tags(root)
 	if err != nil {
 		return err
 	}
@@ -559,7 +568,7 @@ func downloadPackage(p *load.Package) error {
 	if i := strings.Index(vers, " "); i >= 0 {
 		vers = vers[:i]
 	}
-	if err := vcs.tagSync(root, selectTag(vers, tags)); err != nil {
+	if err := vcsCmd.TagSync(root, selectTag(vers, tags)); err != nil {
 		return err
 	}
 

libgo/go/cmd/go/internal/get/path.go

@@ -1,192 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package get
-
-import (
-	"fmt"
-	"strings"
-	"unicode"
-	"unicode/utf8"
-)
-
-// The following functions are copied verbatim from golang.org/x/mod/module/module.go,
-// with a change to additionally reject Windows short-names,
-// and one to accept arbitrary letters (golang.org/issue/29101).
-//
-// TODO(bcmills): After the call site for this function is backported,
-// consolidate this back down to a single copy.
-//
-// NOTE: DO NOT MERGE THESE UNTIL WE DECIDE ABOUT ARBITRARY LETTERS IN MODULE MODE.
-
-// CheckImportPath checks that an import path is valid.
-func CheckImportPath(path string) error {
-	if err := checkPath(path, false); err != nil {
-		return fmt.Errorf("malformed import path %q: %v", path, err)
-	}
-	return nil
-}
-
-// checkPath checks that a general path is valid.
-// It returns an error describing why but not mentioning path.
-// Because these checks apply to both module paths and import paths,
-// the caller is expected to add the "malformed ___ path %q: " prefix.
-// fileName indicates whether the final element of the path is a file name
-// (as opposed to a directory name).
-func checkPath(path string, fileName bool) error {
-	if !utf8.ValidString(path) {
-		return fmt.Errorf("invalid UTF-8")
-	}
-	if path == "" {
-		return fmt.Errorf("empty string")
-	}
-	if path[0] == '-' {
-		return fmt.Errorf("leading dash")
-	}
-	if strings.Contains(path, "//") {
-		return fmt.Errorf("double slash")
-	}
-	if path[len(path)-1] == '/' {
-		return fmt.Errorf("trailing slash")
-	}
-	elemStart := 0
-	for i, r := range path {
-		if r == '/' {
-			if err := checkElem(path[elemStart:i], fileName); err != nil {
-				return err
-			}
-			elemStart = i + 1
-		}
-	}
-	if err := checkElem(path[elemStart:], fileName); err != nil {
-		return err
-	}
-	return nil
-}
-
-// checkElem checks whether an individual path element is valid.
-// fileName indicates whether the element is a file name (not a directory name).
-func checkElem(elem string, fileName bool) error {
-	if elem == "" {
-		return fmt.Errorf("empty path element")
-	}
-	if strings.Count(elem, ".") == len(elem) {
-		return fmt.Errorf("invalid path element %q", elem)
-	}
-	if elem[0] == '.' && !fileName {
-		return fmt.Errorf("leading dot in path element")
-	}
-	if elem[len(elem)-1] == '.' {
-		return fmt.Errorf("trailing dot in path element")
-	}
-
-	charOK := pathOK
-	if fileName {
-		charOK = fileNameOK
-	}
-	for _, r := range elem {
-		if !charOK(r) {
-			return fmt.Errorf("invalid char %q", r)
-		}
-	}
-
-	// Windows disallows a bunch of path elements, sadly.
-	// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-	short := elem
-	if i := strings.Index(short, "."); i >= 0 {
-		short = short[:i]
-	}
-	for _, bad := range badWindowsNames {
-		if strings.EqualFold(bad, short) {
-			return fmt.Errorf("disallowed path element %q", elem)
-		}
-	}
-
-	// Reject path components that look like Windows short-names.
-	// Those usually end in a tilde followed by one or more ASCII digits.
-	if tilde := strings.LastIndexByte(short, '~'); tilde >= 0 && tilde < len(short)-1 {
-		suffix := short[tilde+1:]
-		suffixIsDigits := true
-		for _, r := range suffix {
-			if r < '0' || r > '9' {
-				suffixIsDigits = false
-				break
-			}
-		}
-		if suffixIsDigits {
-			return fmt.Errorf("trailing tilde and digits in path element")
-		}
-	}
-
-	return nil
-}
-
-// pathOK reports whether r can appear in an import path element.
-//
-// NOTE: This function DIVERGES from module mode pathOK by accepting Unicode letters.
-func pathOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		return r == '+' || r == '-' || r == '.' || r == '_' || r == '~' ||
-			'0' <= r && r <= '9' ||
-			'A' <= r && r <= 'Z' ||
-			'a' <= r && r <= 'z'
-	}
-	return unicode.IsLetter(r)
-}
-
-// fileNameOK reports whether r can appear in a file name.
-// For now we allow all Unicode letters but otherwise limit to pathOK plus a few more punctuation characters.
-// If we expand the set of allowed characters here, we have to
-// work harder at detecting potential case-folding and normalization collisions.
-// See note about "safe encoding" below.
-func fileNameOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		// Entire set of ASCII punctuation, from which we remove characters:
-		//     ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~
-		// We disallow some shell special characters: " ' * < > ? ` |
-		// (Note that some of those are disallowed by the Windows file system as well.)
-		// We also disallow path separators / : and \ (fileNameOK is only called on path element characters).
-		// We allow spaces (U+0020) in file names.
-		const allowed = "!#$%&()+,-.=@[]^_{}~ "
-		if '0' <= r && r <= '9' || 'A' <= r && r <= 'Z' || 'a' <= r && r <= 'z' {
-			return true
-		}
-		for i := 0; i < len(allowed); i++ {
-			if rune(allowed[i]) == r {
-				return true
-			}
-		}
-		return false
-	}
-	// It may be OK to add more ASCII punctuation here, but only carefully.
-	// For example Windows disallows < > \, and macOS disallows :, so we must not allow those.
-	return unicode.IsLetter(r)
-}
-
-// badWindowsNames are the reserved file path elements on Windows.
-// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-var badWindowsNames = []string{
-	"CON",
-	"PRN",
-	"AUX",
-	"NUL",
-	"COM1",
-	"COM2",
-	"COM3",
-	"COM4",
-	"COM5",
-	"COM6",
-	"COM7",
-	"COM8",
-	"COM9",
-	"LPT1",
-	"LPT2",
-	"LPT3",
-	"LPT4",
-	"LPT5",
-	"LPT6",
-	"LPT7",
-	"LPT8",
-	"LPT9",
-}

libgo/go/cmd/go/internal/help/helpdoc.go

@@ -526,7 +526,7 @@ General-purpose environment variables:
 		Comma-separated list of glob patterns (in the syntax of Go's path.Match)
 		of module path prefixes that should always be fetched directly
 		or that should not be compared against the checksum database.
-		See 'go help module-private'.
+		See 'go help private'.
 	GOROOT
 		The root of the go tree.
 	GOSUMDB
@@ -582,8 +582,8 @@ Architecture-specific environment variables:
 		For GOARCH=arm, the ARM architecture for which to compile.
 		Valid values are 5, 6, 7.
 	GO386
-		For GOARCH=386, the floating point instruction set.
+		For GOARCH=386, how to implement floating point instructions.
-		Valid values are 387, sse2.
+		Valid values are sse2 (default), softfloat.
 	GOMIPS
 		For GOARCH=mips{,le}, whether to use floating point instructions.
 		Valid values are hardfloat (default), softfloat.
@@ -632,6 +632,8 @@ Additional information available from 'go env' but not read from the environment
 		If module-aware mode is disabled, GOMOD will be the empty string.
 	GOTOOLDIR
 		The directory where the go tools (compile, cover, doc, etc...) are installed.
+	GOVERSION
+		The version of the installed Go tree, as reported by runtime.Version.
 	`,
 }
 
@@ -838,6 +840,9 @@ in addition to android tags and files.
 Using GOOS=illumos matches build tags and files as for GOOS=solaris
 in addition to illumos tags and files.
 
+Using GOOS=ios matches build tags and files as for GOOS=darwin
+in addition to ios tags and files.
+
 To keep a file from being considered for the build:
 
 	// +build ignore

libgo/go/cmd/go/internal/imports/build.go

@@ -141,6 +141,9 @@ func matchTag(name string, tags map[string]bool, want bool) bool {
 	if name == "solaris" {
 		have = have || tags["illumos"]
 	}
+	if name == "darwin" {
+		have = have || tags["ios"]
+	}
 	return have == want
 }
 
@@ -158,6 +161,7 @@ func matchTag(name string, tags map[string]bool, want bool) bool {
 // Exceptions:
 //     if GOOS=android, then files with GOOS=linux are also matched.
 //     if GOOS=illumos, then files with GOOS=solaris are also matched.
+//     if GOOS=ios, then files with GOOS=darwin are also matched.
 //
 // If tags["*"] is true, then MatchFile will consider all possible
 // GOOS and GOARCH to be available and will consequently
@@ -208,6 +212,7 @@ var KnownOS = map[string]bool{
 	"freebsd":   true,
 	"hurd":      true,
 	"illumos":   true,
+	"ios":       true,
 	"js":        true,
 	"linux":     true,
 	"nacl":      true, // legacy; don't remove

libgo/go/cmd/go/internal/imports/read.go

@@ -198,7 +198,7 @@ func (r *importReader) readImport(imports *[]string) {
 	r.readString(imports)
 }
 
-// ReadComments is like ioutil.ReadAll, except that it only reads the leading
+// ReadComments is like io.ReadAll, except that it only reads the leading
 // block of comments in the file.
 func ReadComments(f io.Reader) ([]byte, error) {
 	r := &importReader{b: bufio.NewReader(f)}
@@ -210,7 +210,7 @@ func ReadComments(f io.Reader) ([]byte, error) {
 	return r.buf, r.err
 }
 
-// ReadImports is like ioutil.ReadAll, except that it expects a Go file as input
+// ReadImports is like io.ReadAll, except that it expects a Go file as input
 // and stops reading the input once the imports have completed.
 func ReadImports(f io.Reader, reportSyntaxError bool, imports *[]string) ([]byte, error) {
 	r := &importReader{b: bufio.NewReader(f)}

libgo/go/cmd/go/internal/imports/scan.go

@@ -6,16 +6,17 @@ package imports
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io/fs"
-	"os"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
+
+	"cmd/go/internal/fsys"
 )
 
 func ScanDir(dir string, tags map[string]bool) ([]string, []string, error) {
-	infos, err := ioutil.ReadDir(dir)
+	infos, err := fsys.ReadDir(dir)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -25,14 +26,14 @@ func ScanDir(dir string, tags map[string]bool) ([]string, []string, error) {
 
 		// If the directory entry is a symlink, stat it to obtain the info for the
 		// link target instead of the link itself.
-		if info.Mode()&os.ModeSymlink != 0 {
+		if info.Mode()&fs.ModeSymlink != 0 {
-			info, err = os.Stat(filepath.Join(dir, name))
+			info, err = fsys.Stat(filepath.Join(dir, name))
 			if err != nil {
 				continue // Ignore broken symlinks.
 			}
 		}
 
-		if info.Mode().IsRegular() && !strings.HasPrefix(name, "_") && strings.HasSuffix(name, ".go") && MatchFile(name, tags) {
+		if info.Mode().IsRegular() && !strings.HasPrefix(name, "_") && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go") && MatchFile(name, tags) {
 			files = append(files, filepath.Join(dir, name))
 		}
 	}
@@ -49,7 +50,7 @@ func scanFiles(files []string, tags map[string]bool, explicitFiles bool) ([]stri
 	numFiles := 0
 Files:
 	for _, name := range files {
-		r, err := os.Open(name)
+		r, err := fsys.Open(name)
 		if err != nil {
 			return nil, nil, err
 		}

libgo/go/cmd/go/internal/imports/scan_test.go

@@ -7,7 +7,7 @@ package imports
 import (
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
+	"os"
 	"path"
 	"path/filepath"
 	"runtime"
@@ -57,7 +57,7 @@ func TestScan(t *testing.T) {
 func TestScanDir(t *testing.T) {
 	testenv.MustHaveGoBuild(t)
 
-	dirs, err := ioutil.ReadDir("testdata")
+	dirs, err := os.ReadDir("testdata")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -66,7 +66,7 @@ func TestScanDir(t *testing.T) {
 			continue
 		}
 		t.Run(dir.Name(), func(t *testing.T) {
-			tagsData, err := ioutil.ReadFile(filepath.Join("testdata", dir.Name(), "tags.txt"))
+			tagsData, err := os.ReadFile(filepath.Join("testdata", dir.Name(), "tags.txt"))
 			if err != nil {
 				t.Fatalf("error reading tags: %v", err)
 			}
@@ -75,7 +75,7 @@ func TestScanDir(t *testing.T) {
 				tags[t] = true
 			}
 
-			wantData, err := ioutil.ReadFile(filepath.Join("testdata", dir.Name(), "want.txt"))
+			wantData, err := os.ReadFile(filepath.Join("testdata", dir.Name(), "want.txt"))
 			if err != nil {
 				t.Fatalf("error reading want: %v", err)
 			}

libgo/go/cmd/go/internal/imports/tags.go

@@ -4,17 +4,23 @@
 
 package imports
 
-import "cmd/go/internal/cfg"
+import (
+	"cmd/go/internal/cfg"
+	"sync"
+)
 
-var tags map[string]bool
+var (
+	tags     map[string]bool
+	tagsOnce sync.Once
+)
 
 // Tags returns a set of build tags that are true for the target platform.
 // It includes GOOS, GOARCH, the compiler, possibly "cgo",
 // release tags like "go1.13", and user-specified build tags.
 func Tags() map[string]bool {
-	if tags == nil {
+	tagsOnce.Do(func() {
 		tags = loadTags()
-	}
+	})
 	return tags
 }
 
@@ -36,14 +42,17 @@ func loadTags() map[string]bool {
 	return tags
 }
 
-var anyTags map[string]bool
+var (
+	anyTags     map[string]bool
+	anyTagsOnce sync.Once
+)
 
 // AnyTags returns a special set of build tags that satisfy nearly all
 // build tag expressions. Only "ignore" and malformed build tag requirements
 // are considered false.
 func AnyTags() map[string]bool {
-	if anyTags == nil {
+	anyTagsOnce.Do(func() {
 		anyTags = map[string]bool{"*": true}
-	}
+	})
 	return anyTags
 }

libgo/go/cmd/go/internal/imports/testdata/android/.h.go

@@ -0,0 +1,3 @@
+package android
+
+import _ "h"

libgo/go/cmd/go/internal/imports/testdata/illumos/.h.go

@@ -0,0 +1,3 @@
+package android
+
+import _ "h"

libgo/go/cmd/go/internal/list/list.go

@@ -8,7 +8,9 @@ package list
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"encoding/json"
+	"fmt"
 	"io"
 	"os"
 	"sort"
@@ -19,6 +21,7 @@ import (
 	"cmd/go/internal/cache"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/load"
+	"cmd/go/internal/modinfo"
 	"cmd/go/internal/modload"
 	"cmd/go/internal/str"
 	"cmd/go/internal/work"
@@ -63,26 +66,28 @@ to -f '{{.ImportPath}}'. The struct being passed to the template is:
         BinaryOnly    bool     // binary-only package (no longer supported)
         ForTest       string   // package is only for use in named test
         Export        string   // file containing export data (when using -export)
+        BuildID       string   // build ID of the compiled package (when using -export)
         Module        *Module  // info about package's containing module, if any (can be nil)
         Match         []string // command-line patterns matching this package
         DepOnly       bool     // package is only a dependency, not explicitly listed
 
         // Source files
-        GoFiles         []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+        GoFiles         []string   // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
-        CgoFiles        []string // .go source files that import "C"
+        CgoFiles        []string   // .go source files that import "C"
-        CompiledGoFiles []string // .go files presented to compiler (when using -compiled)
+        CompiledGoFiles []string   // .go files presented to compiler (when using -compiled)
-        IgnoredGoFiles  []string // .go source files ignored due to build constraints
+        IgnoredGoFiles  []string   // .go source files ignored due to build constraints
-        CFiles          []string // .c source files
+        IgnoredOtherFiles []string // non-.go source files ignored due to build constraints
-        CXXFiles        []string // .cc, .cxx and .cpp source files
+        CFiles          []string   // .c source files
-        MFiles          []string // .m source files
+        CXXFiles        []string   // .cc, .cxx and .cpp source files
-        HFiles          []string // .h, .hh, .hpp and .hxx source files
+        MFiles          []string   // .m source files
-        FFiles          []string // .f, .F, .for and .f90 Fortran source files
+        HFiles          []string   // .h, .hh, .hpp and .hxx source files
-        SFiles          []string // .s source files
+        FFiles          []string   // .f, .F, .for and .f90 Fortran source files
-        SwigFiles       []string // .swig files
+        SFiles          []string   // .s source files
-        SwigCXXFiles    []string // .swigcxx files
+        SwigFiles       []string   // .swig files
-        SysoFiles       []string // .syso object files to add to archive
+        SwigCXXFiles    []string   // .swigcxx files
-        TestGoFiles     []string // _test.go files in package
+        SysoFiles       []string   // .syso object files to add to archive
-        XTestGoFiles    []string // _test.go files outside package
+        TestGoFiles     []string   // _test.go files in package
+        XTestGoFiles    []string   // _test.go files outside package
 
         // Cgo directives
         CgoCFLAGS    []string // cgo: flags for C compiler
@@ -213,6 +218,7 @@ applied to a Go struct, but now a Module struct:
         Dir       string       // directory holding files for this module, if any
         GoMod     string       // path to go.mod file used when loading this module, if any
         GoVersion string       // go version used in module
+        Retracted string       // retraction information, if any (with -retracted or -u)
         Error     *ModuleError // error loading module
     }
 
@@ -244,14 +250,16 @@ the replaced source code.)
 The -u flag adds information about available upgrades.
 When the latest version of a given module is newer than
 the current one, list -u sets the Module's Update field
-to information about the newer module.
+to information about the newer module. list -u will also set
+the module's Retracted field if the current version is retracted.
 The Module's String method indicates an available upgrade by
 formatting the newer version in brackets after the current version.
+If a version is retracted, the string "(retracted)" will follow it.
 For example, 'go list -m -u all' might print:
 
     my/main/module
     golang.org/x/text v0.3.0 [v0.4.0] => /tmp/text
-    rsc.io/pdf v0.1.1 [v0.1.2]
+    rsc.io/pdf v0.1.1 (retracted) [v0.1.2]
 
 (For tools, 'go list -m -u -json all' may be more convenient to parse.)
 
@@ -261,6 +269,14 @@ to semantic versioning, earliest to latest. The flag also changes
 the default output format to display the module path followed by the
 space-separated version list.
 
+The -retracted flag causes list to report information about retracted
+module versions. When -retracted is used with -f or -json, the Retracted
+field will be set to a string explaining why the version was retracted.
+The string is taken from comments on the retract directive in the
+module's go.mod file. When -retracted is used with -versions, retracted
+versions are listed together with unretracted versions. The -retracted
+flag may be used with or without -m.
+
 The arguments to list -m are interpreted as a list of modules, not packages.
 The main module is the module containing the current directory.
 The active modules are the main module and its dependencies.
@@ -294,23 +310,24 @@ func init() {
 }
 
 var (
-	listCompiled = CmdList.Flag.Bool("compiled", false, "")
+	listCompiled  = CmdList.Flag.Bool("compiled", false, "")
-	listDeps     = CmdList.Flag.Bool("deps", false, "")
+	listDeps      = CmdList.Flag.Bool("deps", false, "")
-	listE        = CmdList.Flag.Bool("e", false, "")
+	listE         = CmdList.Flag.Bool("e", false, "")
-	listExport   = CmdList.Flag.Bool("export", false, "")
+	listExport    = CmdList.Flag.Bool("export", false, "")
-	listFmt      = CmdList.Flag.String("f", "", "")
+	listFmt       = CmdList.Flag.String("f", "", "")
-	listFind     = CmdList.Flag.Bool("find", false, "")
+	listFind      = CmdList.Flag.Bool("find", false, "")
-	listJson     = CmdList.Flag.Bool("json", false, "")
+	listJson      = CmdList.Flag.Bool("json", false, "")
-	listM        = CmdList.Flag.Bool("m", false, "")
+	listM         = CmdList.Flag.Bool("m", false, "")
-	listU        = CmdList.Flag.Bool("u", false, "")
+	listRetracted = CmdList.Flag.Bool("retracted", false, "")
-	listTest     = CmdList.Flag.Bool("test", false, "")
+	listTest      = CmdList.Flag.Bool("test", false, "")
-	listVersions = CmdList.Flag.Bool("versions", false, "")
+	listU         = CmdList.Flag.Bool("u", false, "")
+	listVersions  = CmdList.Flag.Bool("versions", false, "")
 )
 
 var nl = []byte{'\n'}
 
-func runList(cmd *base.Command, args []string) {
+func runList(ctx context.Context, cmd *base.Command, args []string) {
-	modload.LoadTests = *listTest
+	load.ModResolveTests = *listTest
 	work.BuildInit()
 	out := newTrackingWriter(os.Stdout)
 	defer out.w.Flush()
@@ -348,7 +365,7 @@ func runList(cmd *base.Command, args []string) {
 		fm := template.FuncMap{
 			"join":    strings.Join,
 			"context": context,
-			"module":  modload.ModuleInfo,
+			"module":  func(path string) *modinfo.ModulePublic { return modload.ModuleInfo(ctx, path) },
 		}
 		tmpl, err := template.New("main").Funcs(fm).Parse(*listFmt)
 		if err != nil {
@@ -365,6 +382,16 @@ func runList(cmd *base.Command, args []string) {
 		}
 	}
 
+	modload.Init()
+	if *listRetracted {
+		if cfg.BuildMod == "vendor" {
+			base.Fatalf("go list -retracted cannot be used when vendoring is enabled")
+		}
+		if !modload.Enabled() {
+			base.Fatalf("go list -retracted can only be used in module-aware mode")
+		}
+	}
+
 	if *listM {
 		// Module mode.
 		if *listCompiled {
@@ -388,7 +415,7 @@ func runList(cmd *base.Command, args []string) {
 			base.Fatalf("go list -m: not using modules")
 		}
 
-		modload.InitMod() // Parses go.mod and sets cfg.BuildMod.
+		modload.LoadModFile(ctx) // Parses go.mod and sets cfg.BuildMod.
 		if cfg.BuildMod == "vendor" {
 			const actionDisabledFormat = "go list -m: can't %s using the vendor directory\n\t(Use -mod=mod or -mod=readonly to bypass.)"
 
@@ -412,9 +439,7 @@ func runList(cmd *base.Command, args []string) {
 			}
 		}
 
-		modload.LoadBuildList()
+		mods := modload.ListModules(ctx, args, *listU, *listVersions, *listRetracted)
-
-		mods := modload.ListModules(args, *listU, *listVersions)
 		if !*listE {
 			for _, m := range mods {
 				if m.Error != nil {
@@ -446,11 +471,18 @@ func runList(cmd *base.Command, args []string) {
 	}
 
 	load.IgnoreImports = *listFind
-	var pkgs []*load.Package
+	pkgs := load.PackagesAndErrors(ctx, args)
-	if *listE {
+	if !*listE {
-		pkgs = load.PackagesAndErrors(args)
+		w := 0
-	} else {
+		for _, pkg := range pkgs {
-		pkgs = load.Packages(args)
+			if pkg.Error != nil {
+				base.Errorf("%v", pkg.Error)
+				continue
+			}
+			pkgs[w] = pkg
+			w++
+		}
+		pkgs = pkgs[:w]
 		base.ExitIfErrors()
 	}
 
@@ -476,9 +508,9 @@ func runList(cmd *base.Command, args []string) {
 				var pmain, ptest, pxtest *load.Package
 				var err error
 				if *listE {
-					pmain, ptest, pxtest = load.TestPackagesAndErrors(p, nil)
+					pmain, ptest, pxtest = load.TestPackagesAndErrors(ctx, p, nil)
 				} else {
-					pmain, ptest, pxtest, err = load.TestPackagesFor(p, nil)
+					pmain, ptest, pxtest, err = load.TestPackagesFor(ctx, p, nil)
 					if err != nil {
 						base.Errorf("can't load test package: %s", err)
 					}
@@ -520,7 +552,7 @@ func runList(cmd *base.Command, args []string) {
 		// Note that -deps is applied after -test,
 		// so that you only get descriptions of tests for the things named
 		// explicitly on the command line, not for all dependencies.
-		pkgs = load.PackageList(pkgs)
+		pkgs = loadPackageList(pkgs)
 	}
 
 	// Do we need to run a build to gather information?
@@ -538,13 +570,15 @@ func runList(cmd *base.Command, args []string) {
 				a.Deps = append(a.Deps, b.AutoAction(work.ModeInstall, work.ModeInstall, p))
 			}
 		}
-		b.Do(a)
+		b.Do(ctx, a)
 	}
 
 	for _, p := range pkgs {
 		// Show vendor-expanded paths in listing
 		p.TestImports = p.Resolve(p.TestImports)
 		p.XTestImports = p.Resolve(p.XTestImports)
+		p.TestEmbedFiles = p.ResolveEmbed(p.TestEmbedPatterns)
+		p.XTestEmbedFiles = p.ResolveEmbed(p.XTestEmbedPatterns)
 		p.DepOnly = !cmdline[p]
 
 		if *listCompiled {
@@ -555,7 +589,7 @@ func runList(cmd *base.Command, args []string) {
 	if *listTest {
 		all := pkgs
 		if !*listDeps {
-			all = load.PackageList(pkgs)
+			all = loadPackageList(pkgs)
 		}
 		// Update import paths to distinguish the real package p
 		// from p recompiled for q.test.
@@ -605,6 +639,55 @@ func runList(cmd *base.Command, args []string) {
 		}
 	}
 
+	// TODO(golang.org/issue/40676): This mechanism could be extended to support
+	// -u without -m.
+	if *listRetracted {
+		// Load retractions for modules that provide packages that will be printed.
+		// TODO(golang.org/issue/40775): Packages from the same module refer to
+		// distinct ModulePublic instance. It would be nice if they could all point
+		// to the same instance. This would require additional global state in
+		// modload.loaded, so that should be refactored first. For now, we update
+		// all instances.
+		modToArg := make(map[*modinfo.ModulePublic]string)
+		argToMods := make(map[string][]*modinfo.ModulePublic)
+		var args []string
+		addModule := func(mod *modinfo.ModulePublic) {
+			if mod.Version == "" {
+				return
+			}
+			arg := fmt.Sprintf("%s@%s", mod.Path, mod.Version)
+			if argToMods[arg] == nil {
+				args = append(args, arg)
+			}
+			argToMods[arg] = append(argToMods[arg], mod)
+			modToArg[mod] = arg
+		}
+		for _, p := range pkgs {
+			if p.Module == nil {
+				continue
+			}
+			addModule(p.Module)
+			if p.Module.Replace != nil {
+				addModule(p.Module.Replace)
+			}
+		}
+
+		if len(args) > 0 {
+			listU := false
+			listVersions := false
+			rmods := modload.ListModules(ctx, args, listU, listVersions, *listRetracted)
+			for i, arg := range args {
+				rmod := rmods[i]
+				for _, mod := range argToMods[arg] {
+					mod.Retracted = rmod.Retracted
+					if rmod.Error != nil && mod.Error == nil {
+						mod.Error = rmod.Error
+					}
+				}
+			}
+		}
+	}
+
 	// Record non-identity import mappings in p.ImportMap.
 	for _, p := range pkgs {
 		for i, srcPath := range p.Internal.RawImports {
@@ -623,6 +706,23 @@ func runList(cmd *base.Command, args []string) {
 	}
 }
 
+// loadPackageList is like load.PackageList, but prints error messages and exits
+// with nonzero status if listE is not set and any package in the expanded list
+// has errors.
+func loadPackageList(roots []*load.Package) []*load.Package {
+	pkgs := load.PackageList(roots)
+
+	if !*listE {
+		for _, pkg := range pkgs {
+			if pkg.Error != nil {
+				base.Errorf("%v", pkg.Error)
+			}
+		}
+	}
+
+	return pkgs
+}
+
 // TrackingWriter tracks the last byte written on every write so
 // we can avoid printing a newline if one was already written or
 // if there is no output at all.

libgo/go/cmd/go/internal/load/pkg.go

@@ -7,14 +7,16 @@ package load
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"go/build"
 	"go/scanner"
 	"go/token"
-	"io/ioutil"
+	"io/fs"
 	"os"
+	"path"
 	pathpkg "path"
 	"path/filepath"
 	"runtime"
@@ -26,25 +28,14 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
+	"cmd/go/internal/fsys"
 	"cmd/go/internal/modinfo"
+	"cmd/go/internal/modload"
 	"cmd/go/internal/par"
 	"cmd/go/internal/search"
 	"cmd/go/internal/str"
-)
+	"cmd/go/internal/trace"
-
+	"cmd/internal/sys"
-var (
-	// module initialization hook; never nil, no-op if module use is disabled
-	ModInit func()
-
-	// module hooks; nil if module use is disabled
-	ModBinDir            func() string                                                                            // return effective bin directory
-	ModLookup            func(parentPath string, parentIsStd bool, path string) (dir, realPath string, err error) // lookup effective meaning of import
-	ModPackageModuleInfo func(path string) *modinfo.ModulePublic                                                  // return module info for Package struct
-	ModImportPaths       func(args []string) []*search.Match                                                      // expand import paths
-	ModPackageBuildInfo  func(main string, deps []string) string                                                  // return module info to embed in binary
-	ModInfoProg          func(info string, isgccgo bool) []byte                                                   // wrap module info in .go code for binary
-	ModImportFromFiles   func([]string)                                                                           // update go.mod to add modules for imports in these files
-	ModDirImportPath     func(string) string                                                                      // return effective import path for directory
 )
 
 var IgnoreImports bool // control whether we ignore imports in packages
@@ -70,6 +61,7 @@ type PackagePublic struct {
 	ConflictDir   string                `json:",omitempty"` // Dir is hidden by this other directory
 	ForTest       string                `json:",omitempty"` // package is only for use in named test
 	Export        string                `json:",omitempty"` // file containing export data (set by go list -export)
+	BuildID       string                `json:",omitempty"` // build ID of the compiled package (set by go list -export)
 	Module        *modinfo.ModulePublic `json:",omitempty"` // info about package's module, if any
 	Match         []string              `json:",omitempty"` // command-line patterns matching this package
 	Goroot        bool                  `json:",omitempty"` // is this package found in the Go root?
@@ -87,19 +79,24 @@ type PackagePublic struct {
 	// Source files
 	// If you add to this list you MUST add to p.AllFiles (below) too.
 	// Otherwise file name security lists will not apply to any new additions.
-	GoFiles         []string `json:",omitempty"` // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+	GoFiles           []string `json:",omitempty"` // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
-	CgoFiles        []string `json:",omitempty"` // .go source files that import "C"
+	CgoFiles          []string `json:",omitempty"` // .go source files that import "C"
-	CompiledGoFiles []string `json:",omitempty"` // .go output from running cgo on CgoFiles
+	CompiledGoFiles   []string `json:",omitempty"` // .go output from running cgo on CgoFiles
-	IgnoredGoFiles  []string `json:",omitempty"` // .go source files ignored due to build constraints
+	IgnoredGoFiles    []string `json:",omitempty"` // .go source files ignored due to build constraints
-	CFiles          []string `json:",omitempty"` // .c source files
+	IgnoredOtherFiles []string `json:",omitempty"` // non-.go source files ignored due to build constraints
-	CXXFiles        []string `json:",omitempty"` // .cc, .cpp and .cxx source files
+	CFiles            []string `json:",omitempty"` // .c source files
-	MFiles          []string `json:",omitempty"` // .m source files
+	CXXFiles          []string `json:",omitempty"` // .cc, .cpp and .cxx source files
-	HFiles          []string `json:",omitempty"` // .h, .hh, .hpp and .hxx source files
+	MFiles            []string `json:",omitempty"` // .m source files
-	FFiles          []string `json:",omitempty"` // .f, .F, .for and .f90 Fortran source files
+	HFiles            []string `json:",omitempty"` // .h, .hh, .hpp and .hxx source files
-	SFiles          []string `json:",omitempty"` // .s source files
+	FFiles            []string `json:",omitempty"` // .f, .F, .for and .f90 Fortran source files
-	SwigFiles       []string `json:",omitempty"` // .swig files
+	SFiles            []string `json:",omitempty"` // .s source files
-	SwigCXXFiles    []string `json:",omitempty"` // .swigcxx files
+	SwigFiles         []string `json:",omitempty"` // .swig files
-	SysoFiles       []string `json:",omitempty"` // .syso system object files added to package
+	SwigCXXFiles      []string `json:",omitempty"` // .swigcxx files
+	SysoFiles         []string `json:",omitempty"` // .syso system object files added to package
+
+	// Embedded files
+	EmbedPatterns []string `json:",omitempty"` // //go:embed patterns
+	EmbedFiles    []string `json:",omitempty"` // files and directories matched by EmbedPatterns
 
 	// Cgo directives
 	CgoCFLAGS    []string `json:",omitempty"` // cgo: flags for C compiler
@@ -122,10 +119,14 @@ type PackagePublic struct {
 	// Test information
 	// If you add to this list you MUST add to p.AllFiles (below) too.
 	// Otherwise file name security lists will not apply to any new additions.
-	TestGoFiles  []string `json:",omitempty"` // _test.go files in package
+	TestGoFiles        []string `json:",omitempty"` // _test.go files in package
-	TestImports  []string `json:",omitempty"` // imports from TestGoFiles
+	TestImports        []string `json:",omitempty"` // imports from TestGoFiles
-	XTestGoFiles []string `json:",omitempty"` // _test.go files outside package
+	TestEmbedPatterns  []string `json:",omitempty"` // //go:embed patterns
-	XTestImports []string `json:",omitempty"` // imports from XTestGoFiles
+	TestEmbedFiles     []string `json:",omitempty"` // //files matched by EmbedPatterns
+	XTestGoFiles       []string `json:",omitempty"` // _test.go files outside package
+	XTestImports       []string `json:",omitempty"` // imports from XTestGoFiles
+	XTestEmbedPatterns []string `json:",omitempty"` // //go:embed patterns
+	XTestEmbedFiles    []string `json:",omitempty"` // //files matched by EmbedPatterns
 }
 
 // AllFiles returns the names of all the files considered for the package.
@@ -134,11 +135,12 @@ type PackagePublic struct {
 // The go/build package filtered others out (like foo_wrongGOARCH.s)
 // and that's OK.
 func (p *Package) AllFiles() []string {
-	return str.StringList(
+	files := str.StringList(
 		p.GoFiles,
 		p.CgoFiles,
 		// no p.CompiledGoFiles, because they are from GoFiles or generated by us
 		p.IgnoredGoFiles,
+		p.IgnoredOtherFiles,
 		p.CFiles,
 		p.CXXFiles,
 		p.MFiles,
@@ -151,6 +153,27 @@ func (p *Package) AllFiles() []string {
 		p.TestGoFiles,
 		p.XTestGoFiles,
 	)
+
+	// EmbedFiles may overlap with the other files.
+	// Dedup, but delay building the map as long as possible.
+	// Only files in the current directory (no slash in name)
+	// need to be checked against the files variable above.
+	var have map[string]bool
+	for _, file := range p.EmbedFiles {
+		if !strings.Contains(file, "/") {
+			if have == nil {
+				have = make(map[string]bool)
+				for _, file := range files {
+					have[file] = true
+				}
+			}
+			if have[file] {
+				continue
+			}
+		}
+		files = append(files, file)
+	}
+	return files
 }
 
 // Desc returns the package "description", for use in b.showOutput.
@@ -180,6 +203,7 @@ type PackageInternal struct {
 	GobinSubdir       bool                 // install target would be subdir of GOBIN
 	BuildInfo         string               // add this info to package main
 	TestmainGo        *[]byte              // content for _testmain.go
+	Embed             map[string][]string  // //go:embed comment mapping
 
 	Asmflags   []string // -asmflags for this package
 	Gcflags    []string // -gcflags for this package
@@ -197,7 +221,7 @@ type NoGoError struct {
 }
 
 func (e *NoGoError) Error() string {
-	if len(e.Package.constraintIgnoredGoFiles()) > 0 {
+	if len(e.Package.IgnoredGoFiles) > 0 {
 		// Go files exist, but they were ignored due to build constraints.
 		return "build constraints exclude all Go files in " + e.Package.Dir
 	}
@@ -260,8 +284,8 @@ func (p *Package) setLoadPackageDataError(err error, path string, stk *ImportSta
 	// package's source files themselves (scanner errors).
 	//
 	// TODO(matloob): Perhaps make each of those the errors in the first group
-	// (including modload.ImportMissingError, and the corresponding
+	// (including modload.ImportMissingError, ImportMissingSumError, and the
-	// "cannot find package %q in any of" GOPATH-mode error
+	// corresponding "cannot find package %q in any of" GOPATH-mode error
 	// produced in build.(*Context).Import; modload.AmbiguousImportError,
 	// and modload.PackageNotInModuleError; and the malformed module path errors
 	// produced in golang.org/x/mod/module.CheckMod) implement an interface
@@ -342,6 +366,7 @@ func (p *Package) copyBuild(pp *build.Package) {
 	p.GoFiles = pp.GoFiles
 	p.CgoFiles = pp.CgoFiles
 	p.IgnoredGoFiles = pp.IgnoredGoFiles
+	p.IgnoredOtherFiles = pp.IgnoredOtherFiles
 	p.CFiles = pp.CFiles
 	p.CXXFiles = pp.CXXFiles
 	p.MFiles = pp.MFiles
@@ -371,6 +396,9 @@ func (p *Package) copyBuild(pp *build.Package) {
 		p.TestImports = nil
 		p.XTestImports = nil
 	}
+	p.EmbedPatterns = pp.EmbedPatterns
+	p.TestEmbedPatterns = pp.TestEmbedPatterns
+	p.XTestEmbedPatterns = pp.XTestEmbedPatterns
 }
 
 // A PackageError describes an error loading information about a package.
@@ -432,13 +460,17 @@ type ImportPathError interface {
 	ImportPath() string
 }
 
+var (
+	_ ImportPathError = (*importError)(nil)
+	_ ImportPathError = (*modload.ImportMissingError)(nil)
+	_ ImportPathError = (*modload.ImportMissingSumError)(nil)
+)
+
 type importError struct {
 	importPath string
 	err        error // created with fmt.Errorf
 }
 
-var _ ImportPathError = (*importError)(nil)
-
 func ImportErrorf(path, format string, args ...interface{}) ImportPathError {
 	err := &importError{importPath: path, err: fmt.Errorf(format, args...)}
 	if errStr := err.Error(); !strings.Contains(errStr, path) {
@@ -551,7 +583,7 @@ func ReloadPackageNoFlags(arg string, stk *ImportStack) *Package {
 		})
 		packageDataCache.Delete(p.ImportPath)
 	}
-	return LoadImport(arg, base.Cwd, nil, stk, nil, 0)
+	return LoadImport(context.TODO(), arg, base.Cwd, nil, stk, nil, 0)
 }
 
 // dirToImportPath returns the pseudo-import path we use for a package
@@ -603,11 +635,11 @@ const (
 // LoadImport does not set tool flags and should only be used by
 // this package, as part of a bigger load operation, and by GOPATH-based "go get".
 // TODO(rsc): When GOPATH-based "go get" is removed, unexport this function.
-func LoadImport(path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
+func LoadImport(ctx context.Context, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
-	return loadImport(nil, path, srcDir, parent, stk, importPos, mode)
+	return loadImport(ctx, nil, path, srcDir, parent, stk, importPos, mode)
 }
 
-func loadImport(pre *preload, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
+func loadImport(ctx context.Context, pre *preload, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
 	if path == "" {
 		panic("LoadImport called with empty package path")
 	}
@@ -655,7 +687,7 @@ func loadImport(pre *preload, path, srcDir string, parent *Package, stk *ImportS
 		// Load package.
 		// loadPackageData may return bp != nil even if an error occurs,
 		// in order to return partial information.
-		p.load(path, stk, importPos, bp, err)
+		p.load(ctx, path, stk, importPos, bp, err)
 
 		if !cfg.ModulesEnabled && path != cleanImport(path) {
 			p.Error = &PackageError{
@@ -751,7 +783,7 @@ func loadPackageData(path, parentPath, parentDir, parentRoot string, parentIsStd
 	// For vendored imports, it is the expanded form.
 	//
 	// Note that when modules are enabled, local import paths are normally
-	// canonicalized by modload.ImportPaths before now. However, if there's an
+	// canonicalized by modload.LoadPackages before now. However, if there's an
 	// error resolving a local path, it will be returned untransformed
 	// so that 'go list -e' reports something useful.
 	importKey := importSpec{
@@ -768,7 +800,7 @@ func loadPackageData(path, parentPath, parentDir, parentRoot string, parentIsStd
 			r.dir = filepath.Join(parentDir, path)
 			r.path = dirToImportPath(r.dir)
 		} else if cfg.ModulesEnabled {
-			r.dir, r.path, r.err = ModLookup(parentPath, parentIsStd, path)
+			r.dir, r.path, r.err = modload.Lookup(parentPath, parentIsStd, path)
 		} else if mode&ResolveImport != 0 {
 			// We do our own path resolution, because we want to
 			// find out the key to use in packageCache without the
@@ -799,7 +831,7 @@ func loadPackageData(path, parentPath, parentDir, parentRoot string, parentIsStd
 			}
 			data.p, data.err = cfg.BuildContext.ImportDir(r.dir, buildMode)
 			if data.p.Root == "" && cfg.ModulesEnabled {
-				if info := ModPackageModuleInfo(path); info != nil {
+				if info := modload.PackageModuleInfo(path); info != nil {
 					data.p.Root = info.Dir
 				}
 			}
@@ -825,7 +857,7 @@ func loadPackageData(path, parentPath, parentDir, parentRoot string, parentIsStd
 			if cfg.GOBIN != "" {
 				data.p.BinDir = cfg.GOBIN
 			} else if cfg.ModulesEnabled {
-				data.p.BinDir = ModBinDir()
+				data.p.BinDir = modload.BinDir()
 			}
 		}
 
@@ -893,8 +925,8 @@ var preloadWorkerCount = runtime.GOMAXPROCS(0)
 // to ensure preload goroutines are no longer active. This is necessary
 // because of global mutable state that cannot safely be read and written
 // concurrently. In particular, packageDataCache may be cleared by "go get"
-// in GOPATH mode, and modload.loaded (accessed via ModLookup) may be
+// in GOPATH mode, and modload.loaded (accessed via modload.Lookup) may be
-// modified by modload.ImportPaths (ModImportPaths).
+// modified by modload.LoadPackages.
 type preload struct {
 	cancel chan struct{}
 	sema   chan struct{}
@@ -961,6 +993,12 @@ func (pre *preload) preloadImports(imports []string, parent *build.Package) {
 // loadPackageData have completed. The preloader will not make any new calls
 // to loadPackageData.
 func (pre *preload) flush() {
+	// flush is usually deferred.
+	// Don't hang program waiting for workers on panic.
+	if v := recover(); v != nil {
+		panic(v)
+	}
+
 	close(pre.cancel)
 	for i := 0; i < preloadWorkerCount; i++ {
 		pre.sema <- struct{}{}
@@ -980,7 +1018,7 @@ var isDirCache par.Cache
 
 func isDir(path string) bool {
 	return isDirCache.Do(path, func() interface{} {
-		fi, err := os.Stat(path)
+		fi, err := fsys.Stat(path)
 		return err == nil && fi.IsDir()
 	}).(bool)
 }
@@ -1004,7 +1042,7 @@ func ResolveImportPath(parent *Package, path string) (found string) {
 
 func resolveImportPath(path, parentPath, parentDir, parentRoot string, parentIsStd bool) (found string) {
 	if cfg.ModulesEnabled {
-		if _, p, e := ModLookup(parentPath, parentIsStd, path); e == nil {
+		if _, p, e := modload.Lookup(parentPath, parentIsStd, path); e == nil {
 			return p
 		}
 		return path
@@ -1108,7 +1146,7 @@ var (
 // goModPath returns the module path in the go.mod in dir, if any.
 func goModPath(dir string) (path string) {
 	return goModPathCache.Do(dir, func() interface{} {
-		data, err := ioutil.ReadFile(filepath.Join(dir, "go.mod"))
+		data, err := os.ReadFile(filepath.Join(dir, "go.mod"))
 		if err != nil {
 			return ""
 		}
@@ -1257,9 +1295,9 @@ HaveGoMod:
 // Otherwise it is not possible to vendor just a/b/c and still import the
 // non-vendored a/b. See golang.org/issue/13832.
 func hasGoFiles(dir string) bool {
-	fis, _ := ioutil.ReadDir(dir)
+	files, _ := os.ReadDir(dir)
-	for _, fi := range fis {
+	for _, f := range files {
-		if !fi.IsDir() && strings.HasSuffix(fi.Name(), ".go") {
+		if !f.IsDir() && strings.HasSuffix(f.Name(), ".go") {
 			return true
 		}
 	}
@@ -1373,7 +1411,7 @@ func disallowInternal(srcDir string, importer *Package, importerPath string, p *
 			// directory containing them.
 			// If the directory is outside the main module, this will resolve to ".",
 			// which is not a prefix of any valid module.
-			importerPath = ModDirImportPath(importer.Dir)
+			importerPath = modload.DirImportPath(importer.Dir)
 		}
 		parentOfInternal := p.ImportPath[:i]
 		if str.HasPathPrefix(importerPath, parentOfInternal) {
@@ -1595,7 +1633,7 @@ func (p *Package) DefaultExecName() string {
 // load populates p using information from bp, err, which should
 // be the result of calling build.Context.Import.
 // stk contains the import stack, not including path itself.
-func (p *Package) load(path string, stk *ImportStack, importPos []token.Position, bp *build.Package, err error) {
+func (p *Package) load(ctx context.Context, path string, stk *ImportStack, importPos []token.Position, bp *build.Package, err error) {
 	p.copyBuild(bp)
 
 	// The localPrefix is the path we interpret ./ imports relative to.
@@ -1631,6 +1669,11 @@ func (p *Package) load(path string, stk *ImportStack, importPos []token.Position
 		p.setLoadPackageDataError(err, path, stk, importPos)
 	}
 
+	p.EmbedFiles, p.Internal.Embed, err = p.resolveEmbed(p.EmbedPatterns)
+	if err != nil {
+		setError(err)
+	}
+
 	useBindir := p.Name == "main"
 	if !p.Standard {
 		switch cfg.BuildBuildmode {
@@ -1656,7 +1699,7 @@ func (p *Package) load(path string, stk *ImportStack, importPos []token.Position
 			elem = full
 		}
 		if p.Internal.Build.BinDir == "" && cfg.ModulesEnabled {
-			p.Internal.Build.BinDir = ModBinDir()
+			p.Internal.Build.BinDir = modload.BinDir()
 		}
 		if p.Internal.Build.BinDir != "" {
 			// Install to GOBIN or bin of GOPATH entry.
@@ -1690,7 +1733,7 @@ func (p *Package) load(path string, stk *ImportStack, importPos []token.Position
 			// not work for any package that lacks a Target — such as a non-main
 			// package in module mode. We should probably fix that.
 			shlibnamefile := p.Target[:len(p.Target)-2] + ".shlibname"
-			shlib, err := ioutil.ReadFile(shlibnamefile)
+			shlib, err := os.ReadFile(shlibnamefile)
 			if err != nil && !os.IsNotExist(err) {
 				base.Fatalf("reading shlibname: %v", err)
 			}
@@ -1804,7 +1847,7 @@ func (p *Package) load(path string, stk *ImportStack, importPos []token.Position
 		if path == "C" {
 			continue
 		}
-		p1 := LoadImport(path, p.Dir, p, stk, p.Internal.Build.ImportPos[path], ResolveImport)
+		p1 := LoadImport(ctx, path, p.Dir, p, stk, p.Internal.Build.ImportPos[path], ResolveImport)
 
 		path = p1.ImportPath
 		importPaths[i] = path
@@ -1865,13 +1908,169 @@ func (p *Package) load(path string, stk *ImportStack, importPos []token.Position
 		if p.Internal.CmdlineFiles {
 			mainPath = "command-line-arguments"
 		}
-		p.Module = ModPackageModuleInfo(mainPath)
+		p.Module = modload.PackageModuleInfo(mainPath)
 		if p.Name == "main" && len(p.DepsErrors) == 0 {
-			p.Internal.BuildInfo = ModPackageBuildInfo(mainPath, p.Deps)
+			p.Internal.BuildInfo = modload.PackageBuildInfo(mainPath, p.Deps)
 		}
 	}
 }
 
+// ResolveEmbed resolves //go:embed patterns and returns only the file list.
+// For use by go list to compute p.TestEmbedFiles and p.XTestEmbedFiles.
+func (p *Package) ResolveEmbed(patterns []string) []string {
+	files, _, _ := p.resolveEmbed(patterns)
+	return files
+}
+
+// resolveEmbed resolves //go:embed patterns to precise file lists.
+// It sets files to the list of unique files matched (for go list),
+// and it sets pmap to the more precise mapping from
+// patterns to files.
+// TODO(rsc): All these messages need position information for better error reports.
+func (p *Package) resolveEmbed(patterns []string) (files []string, pmap map[string][]string, err error) {
+	pmap = make(map[string][]string)
+	have := make(map[string]int)
+	dirOK := make(map[string]bool)
+	pid := 0 // pattern ID, to allow reuse of have map
+	for _, pattern := range patterns {
+		pid++
+
+		// Check pattern is valid for //go:embed.
+		if _, err := path.Match(pattern, ""); err != nil || !validEmbedPattern(pattern) {
+			return nil, nil, fmt.Errorf("pattern %s: invalid pattern syntax", pattern)
+		}
+
+		// Glob to find matches.
+		match, err := fsys.Glob(p.Dir + string(filepath.Separator) + filepath.FromSlash(pattern))
+		if err != nil {
+			return nil, nil, fmt.Errorf("pattern %s: %v", pattern, err)
+		}
+
+		// Filter list of matches down to the ones that will still exist when
+		// the directory is packaged up as a module. (If p.Dir is in the module cache,
+		// only those files exist already, but if p.Dir is in the current module,
+		// then there may be other things lying around, like symbolic links or .git directories.)
+		var list []string
+		for _, file := range match {
+			rel := filepath.ToSlash(file[len(p.Dir)+1:]) // file, relative to p.Dir
+
+			what := "file"
+			info, err := fsys.Lstat(file)
+			if err != nil {
+				return nil, nil, err
+			}
+			if info.IsDir() {
+				what = "directory"
+			}
+
+			// Check that directories along path do not begin a new module
+			// (do not contain a go.mod).
+			for dir := file; len(dir) > len(p.Dir)+1 && !dirOK[dir]; dir = filepath.Dir(dir) {
+				if _, err := fsys.Stat(filepath.Join(dir, "go.mod")); err == nil {
+					return nil, nil, fmt.Errorf("pattern %s: cannot embed %s %s: in different module", pattern, what, rel)
+				}
+				if dir != file {
+					if info, err := fsys.Lstat(dir); err == nil && !info.IsDir() {
+						return nil, nil, fmt.Errorf("pattern %s: cannot embed %s %s: in non-directory %s", pattern, what, rel, dir[len(p.Dir)+1:])
+					}
+				}
+				dirOK[dir] = true
+				if elem := filepath.Base(dir); isBadEmbedName(elem) {
+					if dir == file {
+						return nil, nil, fmt.Errorf("pattern %s: cannot embed %s %s: invalid name %s", pattern, what, rel, elem)
+					} else {
+						return nil, nil, fmt.Errorf("pattern %s: cannot embed %s %s: in invalid directory %s", pattern, what, rel, elem)
+					}
+				}
+			}
+
+			switch {
+			default:
+				return nil, nil, fmt.Errorf("pattern %s: cannot embed irregular file %s", pattern, rel)
+
+			case info.Mode().IsRegular():
+				if have[rel] != pid {
+					have[rel] = pid
+					list = append(list, rel)
+				}
+
+			case info.IsDir():
+				// Gather all files in the named directory, stopping at module boundaries
+				// and ignoring files that wouldn't be packaged into a module.
+				count := 0
+				err := fsys.Walk(file, func(path string, info os.FileInfo, err error) error {
+					if err != nil {
+						return err
+					}
+					rel := filepath.ToSlash(path[len(p.Dir)+1:])
+					name := info.Name()
+					if path != file && (isBadEmbedName(name) || name[0] == '.' || name[0] == '_') {
+						// Ignore bad names, assuming they won't go into modules.
+						// Also avoid hidden files that user may not know about.
+						// See golang.org/issue/42328.
+						if info.IsDir() {
+							return fs.SkipDir
+						}
+						return nil
+					}
+					if info.IsDir() {
+						if _, err := fsys.Stat(filepath.Join(path, "go.mod")); err == nil {
+							return filepath.SkipDir
+						}
+						return nil
+					}
+					if !info.Mode().IsRegular() {
+						return nil
+					}
+					count++
+					if have[rel] != pid {
+						have[rel] = pid
+						list = append(list, rel)
+					}
+					return nil
+				})
+				if err != nil {
+					return nil, nil, err
+				}
+				if count == 0 {
+					return nil, nil, fmt.Errorf("pattern %s: cannot embed directory %s: contains no embeddable files", pattern, rel)
+				}
+			}
+		}
+
+		if len(list) == 0 {
+			return nil, nil, fmt.Errorf("pattern %s: no matching files found", pattern)
+		}
+		sort.Strings(list)
+		pmap[pattern] = list
+	}
+
+	for file := range have {
+		files = append(files, file)
+	}
+	sort.Strings(files)
+	return files, pmap, nil
+}
+
+func validEmbedPattern(pattern string) bool {
+	return pattern != "." && fs.ValidPath(pattern)
+}
+
+// isBadEmbedName reports whether name is the base name of a file that
+// can't or won't be included in modules and therefore shouldn't be treated
+// as existing for embedding.
+func isBadEmbedName(name string) bool {
+	switch name {
+	// Empty string should be impossible but make it bad.
+	case "":
+		return true
+	// Version control directories won't be present in module.
+	case ".bzr", ".hg", ".git", ".svn":
+		return true
+	}
+	return false
+}
+
 // collectDeps populates p.Deps and p.DepsErrors by iterating over
 // p.Internal.Imports.
 //
@@ -1959,37 +2158,40 @@ func LinkerDeps(p *Package) []string {
 // externalLinkingForced reports whether external linking is being
 // forced even for programs that do not use cgo.
 func externalLinkingForced(p *Package) bool {
+	if !cfg.BuildContext.CgoEnabled {
+		return false
+	}
+
 	// Some targets must use external linking even inside GOROOT.
 	switch cfg.BuildContext.GOOS {
 	case "android":
 		if cfg.BuildContext.GOARCH != "arm64" {
 			return true
 		}
-	case "darwin":
+	case "ios":
-		if cfg.BuildContext.GOARCH == "arm64" {
+		return true
-			return true
-		}
 	}
 
-	if !cfg.BuildContext.CgoEnabled {
-		return false
-	}
 	// Currently build modes c-shared, pie (on systems that do not
 	// support PIE with internal linking mode (currently all
 	// systems: issue #18968)), plugin, and -linkshared force
 	// external linking mode, as of course does
 	// -ldflags=-linkmode=external. External linking mode forces
 	// an import of runtime/cgo.
-	pieCgo := cfg.BuildBuildmode == "pie"
+	// If there are multiple -linkmode options, the last one wins.
+	pieCgo := cfg.BuildBuildmode == "pie" && !sys.InternalLinkPIESupported(cfg.BuildContext.GOOS, cfg.BuildContext.GOARCH)
 	linkmodeExternal := false
 	if p != nil {
 		ldflags := BuildLdflags.For(p)
-		for i, a := range ldflags {
+		for i := len(ldflags) - 1; i >= 0; i-- {
-			if a == "-linkmode=external" {
+			a := ldflags[i]
-				linkmodeExternal = true
+			if a == "-linkmode=external" ||
-			}
+				a == "-linkmode" && i+1 < len(ldflags) && ldflags[i+1] == "external" {
-			if a == "-linkmode" && i+1 < len(ldflags) && ldflags[i+1] == "external" {
 				linkmodeExternal = true
+				break
+			} else if a == "-linkmode=internal" ||
+				a == "-linkmode" && i+1 < len(ldflags) && ldflags[i+1] == "internal" {
+				break
 			}
 		}
 	}
@@ -2024,22 +2226,7 @@ func (p *Package) InternalXGoFiles() []string {
 // using absolute paths. "Possibly relevant" means that files are not excluded
 // due to build tags, but files with names beginning with . or _ are still excluded.
 func (p *Package) InternalAllGoFiles() []string {
-	return p.mkAbs(str.StringList(p.constraintIgnoredGoFiles(), p.GoFiles, p.CgoFiles, p.TestGoFiles, p.XTestGoFiles))
+	return p.mkAbs(str.StringList(p.IgnoredGoFiles, p.GoFiles, p.CgoFiles, p.TestGoFiles, p.XTestGoFiles))
-}
-
-// constraintIgnoredGoFiles returns the list of Go files ignored for reasons
-// other than having a name beginning with '.' or '_'.
-func (p *Package) constraintIgnoredGoFiles() []string {
-	if len(p.IgnoredGoFiles) == 0 {
-		return nil
-	}
-	files := make([]string, 0, len(p.IgnoredGoFiles))
-	for _, f := range p.IgnoredGoFiles {
-		if f != "" && f[0] != '.' && f[0] != '_' {
-			files = append(files, f)
-		}
-	}
-	return files
 }
 
 // usesSwig reports whether the package needs to run SWIG.
@@ -2077,7 +2264,7 @@ func PackageList(roots []*Package) []*Package {
 // TestPackageList returns the list of packages in the dag rooted at roots
 // as visited in a depth-first post-order traversal, including the test
 // imports of the roots. This ignores errors in test packages.
-func TestPackageList(roots []*Package) []*Package {
+func TestPackageList(ctx context.Context, roots []*Package) []*Package {
 	seen := map[*Package]bool{}
 	all := []*Package{}
 	var walk func(*Package)
@@ -2093,7 +2280,7 @@ func TestPackageList(roots []*Package) []*Package {
 	}
 	walkTest := func(root *Package, path string) {
 		var stk ImportStack
-		p1 := LoadImport(path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
+		p1 := LoadImport(ctx, path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
 		if p1.Error == nil {
 			walk(p1)
 		}
@@ -2116,36 +2303,35 @@ func TestPackageList(roots []*Package) []*Package {
 // TODO(jayconrod): delete this function and set flags automatically
 // in LoadImport instead.
 func LoadImportWithFlags(path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
-	p := LoadImport(path, srcDir, parent, stk, importPos, mode)
+	p := LoadImport(context.TODO(), path, srcDir, parent, stk, importPos, mode)
 	setToolFlags(p)
 	return p
 }
 
-// Packages returns the packages named by the
+// ModResolveTests indicates whether calls to the module loader should also
-// command line arguments 'args'. If a named package
+// resolve test dependencies of the requested packages.
-// cannot be loaded at all (for example, if the directory does not exist),
+//
-// then packages prints an error and does not include that
+// If ModResolveTests is true, then the module loader needs to resolve test
-// package in the results. However, if errors occur trying
+// dependencies at the same time as packages; otherwise, the test dependencies
-// to load dependencies of a named package, the named
+// of those packages could be missing, and resolving those missing dependencies
-// package is still returned, with p.Incomplete = true
+// could change the selected versions of modules that provide other packages.
-// and details in p.DepsErrors.
+//
-func Packages(args []string) []*Package {
+// TODO(#40775): Change this from a global variable to an explicit function
-	var pkgs []*Package
+// argument where needed.
-	for _, pkg := range PackagesAndErrors(args) {
+var ModResolveTests bool
-		if pkg.Error != nil {
+
-			base.Errorf("%v", pkg.Error)
+// PackagesAndErrors returns the packages named by the command line arguments
-			continue
+// 'patterns'. If a named package cannot be loaded, PackagesAndErrors returns
-		}
+// a *Package with the Error field describing the failure. If errors are found
-		pkgs = append(pkgs, pkg)
+// loading imported packages, the DepsErrors field is set. The Incomplete field
-	}
+// may be set as well.
-	return pkgs
+//
-}
+// To obtain a flat list of packages, use PackageList.
+// To report errors loading packages, use ReportPackageErrors.
+func PackagesAndErrors(ctx context.Context, patterns []string) []*Package {
+	ctx, span := trace.StartSpan(ctx, "load.PackagesAndErrors")
+	defer span.Done()
 
-// PackagesAndErrors is like 'packages' but returns a
-// *Package for every argument, even the ones that
-// cannot be loaded at all.
-// The packages that fail to load will have p.Error != nil.
-func PackagesAndErrors(patterns []string) []*Package {
 	for _, p := range patterns {
 		// Listing is only supported with all patterns referring to either:
 		// - Files that are part of the same directory.
@@ -2153,13 +2339,24 @@ func PackagesAndErrors(patterns []string) []*Package {
 		if strings.HasSuffix(p, ".go") {
 			// We need to test whether the path is an actual Go file and not a
 			// package path or pattern ending in '.go' (see golang.org/issue/34653).
-			if fi, err := os.Stat(p); err == nil && !fi.IsDir() {
+			if fi, err := fsys.Stat(p); err == nil && !fi.IsDir() {
-				return []*Package{GoFilesPackage(patterns)}
+				return []*Package{GoFilesPackage(ctx, patterns)}
 			}
 		}
 	}
 
-	matches := ImportPaths(patterns)
+	var matches []*search.Match
+	if modload.Init(); cfg.ModulesEnabled {
+		loadOpts := modload.PackageOpts{
+			ResolveMissingImports: true,
+			LoadTests:             ModResolveTests,
+			SilenceErrors:         true,
+		}
+		matches, _ = modload.LoadPackages(ctx, loadOpts, patterns...)
+	} else {
+		matches = search.ImportPaths(patterns)
+	}
+
 	var (
 		pkgs    []*Package
 		stk     ImportStack
@@ -2175,7 +2372,7 @@ func PackagesAndErrors(patterns []string) []*Package {
 			if pkg == "" {
 				panic(fmt.Sprintf("ImportPaths returned empty package for pattern %s", m.Pattern()))
 			}
-			p := loadImport(pre, pkg, base.Cwd, nil, &stk, nil, 0)
+			p := loadImport(ctx, pre, pkg, base.Cwd, nil, &stk, nil, 0)
 			p.Match = append(p.Match, m.Pattern())
 			p.Internal.CmdlinePkg = true
 			if m.IsLiteral() {
@@ -2220,27 +2417,9 @@ func PackagesAndErrors(patterns []string) []*Package {
 	return pkgs
 }
 
-func setToolFlags(pkgs ...*Package) {
+// CheckPackageErrors prints errors encountered loading pkgs and their
-	for _, p := range PackageList(pkgs) {
+// dependencies, then exits with a non-zero status if any errors were found.
-		p.Internal.Asmflags = BuildAsmflags.For(p)
+func CheckPackageErrors(pkgs []*Package) {
-		p.Internal.Gcflags = BuildGcflags.For(p)
-		p.Internal.Ldflags = BuildLdflags.For(p)
-		p.Internal.Gccgoflags = BuildGccgoflags.For(p)
-	}
-}
-
-func ImportPaths(args []string) []*search.Match {
-	if ModInit(); cfg.ModulesEnabled {
-		return ModImportPaths(args)
-	}
-	return search.ImportPaths(args)
-}
-
-// PackagesForBuild is like Packages but exits
-// if any of the packages or their dependencies have errors
-// (cannot be built).
-func PackagesForBuild(args []string) []*Package {
-	pkgs := PackagesAndErrors(args)
 	printed := map[*PackageError]bool{}
 	for _, pkg := range pkgs {
 		if pkg.Error != nil {
@@ -2275,15 +2454,22 @@ func PackagesForBuild(args []string) []*Package {
 		seen[pkg.ImportPath] = true
 	}
 	base.ExitIfErrors()
+}
 
-	return pkgs
+func setToolFlags(pkgs ...*Package) {
+	for _, p := range PackageList(pkgs) {
+		p.Internal.Asmflags = BuildAsmflags.For(p)
+		p.Internal.Gcflags = BuildGcflags.For(p)
+		p.Internal.Ldflags = BuildLdflags.For(p)
+		p.Internal.Gccgoflags = BuildGccgoflags.For(p)
+	}
 }
 
 // GoFilesPackage creates a package for building a collection of Go files
 // (typically named on the command line). The target is named p.a for
 // package p or named after the first Go file for package main.
-func GoFilesPackage(gofiles []string) *Package {
+func GoFilesPackage(ctx context.Context, gofiles []string) *Package {
-	ModInit()
+	modload.Init()
 
 	for _, f := range gofiles {
 		if !strings.HasSuffix(f, ".go") {
@@ -2306,10 +2492,10 @@ func GoFilesPackage(gofiles []string) *Package {
 	// to make it look like this is a standard package or
 	// command directory. So that local imports resolve
 	// consistently, the files must all be in the same directory.
-	var dirent []os.FileInfo
+	var dirent []fs.FileInfo
 	var dir string
 	for _, file := range gofiles {
-		fi, err := os.Stat(file)
+		fi, err := fsys.Stat(file)
 		if err != nil {
 			base.Fatalf("%s", err)
 		}
@@ -2327,10 +2513,10 @@ func GoFilesPackage(gofiles []string) *Package {
 		}
 		dirent = append(dirent, fi)
 	}
-	ctxt.ReadDir = func(string) ([]os.FileInfo, error) { return dirent, nil }
+	ctxt.ReadDir = func(string) ([]fs.FileInfo, error) { return dirent, nil }
 
 	if cfg.ModulesEnabled {
-		ModImportFromFiles(gofiles)
+		modload.ImportFromFiles(ctx, gofiles)
 	}
 
 	var err error
@@ -2346,7 +2532,7 @@ func GoFilesPackage(gofiles []string) *Package {
 	pkg := new(Package)
 	pkg.Internal.Local = true
 	pkg.Internal.CmdlineFiles = true
-	pkg.load("command-line-arguments", &stk, nil, bp, err)
+	pkg.load(ctx, "command-line-arguments", &stk, nil, bp, err)
 	pkg.Internal.LocalPrefix = dirToImportPath(dir)
 	pkg.ImportPath = "command-line-arguments"
 	pkg.Target = ""
@@ -2358,7 +2544,7 @@ func GoFilesPackage(gofiles []string) *Package {
 		if cfg.GOBIN != "" {
 			pkg.Target = filepath.Join(cfg.GOBIN, exe)
 		} else if cfg.ModulesEnabled {
-			pkg.Target = filepath.Join(ModBinDir(), exe)
+			pkg.Target = filepath.Join(modload.BinDir(), exe)
 		}
 	}
 

libgo/go/cmd/go/internal/load/test.go

@@ -6,7 +6,7 @@ package load
 
 import (
 	"bytes"
-	"cmd/go/internal/str"
+	"context"
 	"errors"
 	"fmt"
 	"go/ast"
@@ -20,6 +20,9 @@ import (
 	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"cmd/go/internal/str"
+	"cmd/go/internal/trace"
 )
 
 var TestMainDeps = []string{
@@ -42,8 +45,8 @@ type TestCover struct {
 // TestPackagesFor is like TestPackagesAndErrors but it returns
 // an error if the test packages or their dependencies have errors.
 // Only test packages without errors are returned.
-func TestPackagesFor(p *Package, cover *TestCover) (pmain, ptest, pxtest *Package, err error) {
+func TestPackagesFor(ctx context.Context, p *Package, cover *TestCover) (pmain, ptest, pxtest *Package, err error) {
-	pmain, ptest, pxtest = TestPackagesAndErrors(p, cover)
+	pmain, ptest, pxtest = TestPackagesAndErrors(ctx, p, cover)
 	for _, p1 := range []*Package{ptest, pxtest, pmain} {
 		if p1 == nil {
 			// pxtest may be nil
@@ -89,7 +92,10 @@ func TestPackagesFor(p *Package, cover *TestCover) (pmain, ptest, pxtest *Packag
 //
 // The caller is expected to have checked that len(p.TestGoFiles)+len(p.XTestGoFiles) > 0,
 // or else there's no point in any of this.
-func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *Package) {
+func TestPackagesAndErrors(ctx context.Context, p *Package, cover *TestCover) (pmain, ptest, pxtest *Package) {
+	ctx, span := trace.StartSpan(ctx, "load.TestPackagesAndErrors")
+	defer span.Done()
+
 	pre := newPreload()
 	defer pre.flush()
 	allImports := append([]string{}, p.TestImports...)
@@ -99,10 +105,11 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 	var ptestErr, pxtestErr *PackageError
 	var imports, ximports []*Package
 	var stk ImportStack
+	var testEmbed, xtestEmbed map[string][]string
 	stk.Push(p.ImportPath + " (test)")
 	rawTestImports := str.StringList(p.TestImports)
 	for i, path := range p.TestImports {
-		p1 := loadImport(pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
+		p1 := loadImport(ctx, pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
 		if str.Contains(p1.Deps, p.ImportPath) || p1.ImportPath == p.ImportPath {
 			// Same error that loadPackage returns (via reusePackage) in pkg.go.
 			// Can't change that code, because that code is only for loading the
@@ -116,12 +123,21 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 		p.TestImports[i] = p1.ImportPath
 		imports = append(imports, p1)
 	}
+	var err error
+	p.TestEmbedFiles, testEmbed, err = p.resolveEmbed(p.TestEmbedPatterns)
+	if err != nil && ptestErr == nil {
+		ptestErr = &PackageError{
+			ImportStack: stk.Copy(),
+			Err:         err,
+		}
+	}
 	stk.Pop()
+
 	stk.Push(p.ImportPath + "_test")
 	pxtestNeedsPtest := false
 	rawXTestImports := str.StringList(p.XTestImports)
 	for i, path := range p.XTestImports {
-		p1 := loadImport(pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
+		p1 := loadImport(ctx, pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
 		if p1.ImportPath == p.ImportPath {
 			pxtestNeedsPtest = true
 		} else {
@@ -129,6 +145,13 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 		}
 		p.XTestImports[i] = p1.ImportPath
 	}
+	p.XTestEmbedFiles, xtestEmbed, err = p.resolveEmbed(p.XTestEmbedPatterns)
+	if err != nil && pxtestErr == nil {
+		pxtestErr = &PackageError{
+			ImportStack: stk.Copy(),
+			Err:         err,
+		}
+	}
 	stk.Pop()
 
 	// Test package.
@@ -168,6 +191,14 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 			m[k] = append(m[k], v...)
 		}
 		ptest.Internal.Build.ImportPos = m
+		if testEmbed == nil && len(p.Internal.Embed) > 0 {
+			testEmbed = map[string][]string{}
+		}
+		for k, v := range p.Internal.Embed {
+			testEmbed[k] = v
+		}
+		ptest.Internal.Embed = testEmbed
+		ptest.EmbedFiles = str.StringList(p.EmbedFiles, p.TestEmbedFiles)
 		ptest.collectDeps()
 	} else {
 		ptest = p
@@ -185,7 +216,9 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 				GoFiles:    p.XTestGoFiles,
 				Imports:    p.XTestImports,
 				ForTest:    p.ImportPath,
+				Module:     p.Module,
 				Error:      pxtestErr,
+				EmbedFiles: p.XTestEmbedFiles,
 			},
 			Internal: PackageInternal{
 				LocalPrefix: p.Internal.LocalPrefix,
@@ -199,6 +232,7 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 				Gcflags:    p.Internal.Gcflags,
 				Ldflags:    p.Internal.Ldflags,
 				Gccgoflags: p.Internal.Gccgoflags,
+				Embed:      xtestEmbed,
 			},
 		}
 		if pxtestNeedsPtest {
@@ -216,6 +250,7 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 			ImportPath: p.ImportPath + ".test",
 			Root:       p.Root,
 			Imports:    str.StringList(TestMainDeps),
+			Module:     p.Module,
 		},
 		Internal: PackageInternal{
 			Build:      &build.Package{Name: "main"},
@@ -238,7 +273,7 @@ func TestPackagesAndErrors(p *Package, cover *TestCover) (pmain, ptest, pxtest *
 		if dep == ptest.ImportPath {
 			pmain.Internal.Imports = append(pmain.Internal.Imports, ptest)
 		} else {
-			p1 := loadImport(pre, dep, "", nil, &stk, nil, 0)
+			p1 := loadImport(ctx, pre, dep, "", nil, &stk, nil, 0)
 			pmain.Internal.Imports = append(pmain.Internal.Imports, p1)
 		}
 	}

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock.go

@@ -9,6 +9,7 @@ package filelock
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 )
 
@@ -24,7 +25,7 @@ type File interface {
 	Fd() uintptr
 
 	// Stat returns the FileInfo structure describing file.
-	Stat() (os.FileInfo, error)
+	Stat() (fs.FileInfo, error)
 }
 
 // Lock places an advisory write lock on the file, blocking until it can be
@@ -87,7 +88,7 @@ var ErrNotSupported = errors.New("operation not supported")
 // underlyingError returns the underlying error for known os error types.
 func underlyingError(err error) error {
 	switch err := err.(type) {
-	case *os.PathError:
+	case *fs.PathError:
 		return err.Err
 	case *os.LinkError:
 		return err.Err

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock_fcntl.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix solaris
+// +build aix solaris,!illumos
 
 // This code implements the filelock API using POSIX 'fcntl' locks, which attach
 // to an (inode, process) pair rather than a file descriptor. To avoid unlocking
@@ -12,17 +12,14 @@
 // Most platforms provide some alternative API, such as an 'flock' system call
 // or an F_OFD_SETLK command for 'fcntl', that allows for better concurrency and
 // does not require per-inode bookkeeping in the application.
-//
-// TODO(golang.org/issue/35618): add a syscall.Flock binding for Illumos and
-// switch it over to use filelock_unix.go.
 
 package filelock
 
 import (
 	"errors"
 	"io"
+	"io/fs"
 	"math/rand"
-	"os"
 	"sync"
 	"syscall"
 	"time"
@@ -66,7 +63,7 @@ func lock(f File, lt lockType) (err error) {
 	mu.Lock()
 	if i, dup := inodes[f]; dup && i != ino {
 		mu.Unlock()
-		return &os.PathError{
+		return &fs.PathError{
 			Op:   lt.String(),
 			Path: f.Name(),
 			Err:  errors.New("inode for file changed since last Lock or RLock"),
@@ -157,7 +154,7 @@ func lock(f File, lt lockType) (err error) {
 
 	if err != nil {
 		unlock(f)
-		return &os.PathError{
+		return &fs.PathError{
 			Op:   lt.String(),
 			Path: f.Name(),
 			Err:  err,

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock_other.go

@@ -6,7 +6,7 @@
 
 package filelock
 
-import "os"
+import "io/fs"
 
 type lockType int8
 
@@ -16,7 +16,7 @@ const (
 )
 
 func lock(f File, lt lockType) error {
-	return &os.PathError{
+	return &fs.PathError{
 		Op:   lt.String(),
 		Path: f.Name(),
 		Err:  ErrNotSupported,
@@ -24,7 +24,7 @@ func lock(f File, lt lockType) error {
 }
 
 func unlock(f File) error {
-	return &os.PathError{
+	return &fs.PathError{
 		Op:   "Unlock",
 		Path: f.Name(),
 		Err:  ErrNotSupported,

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock_plan9.go

@@ -6,9 +6,7 @@
 
 package filelock
 
-import (
+import "io/fs"
-	"os"
-)
 
 type lockType int8
 
@@ -18,7 +16,7 @@ const (
 )
 
 func lock(f File, lt lockType) error {
-	return &os.PathError{
+	return &fs.PathError{
 		Op:   lt.String(),
 		Path: f.Name(),
 		Err:  ErrNotSupported,
@@ -26,7 +24,7 @@ func lock(f File, lt lockType) error {
 }
 
 func unlock(f File) error {
-	return &os.PathError{
+	return &fs.PathError{
 		Op:   "Unlock",
 		Path: f.Name(),
 		Err:  ErrNotSupported,

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock_test.go

@@ -9,7 +9,6 @@ package filelock_test
 import (
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -51,9 +50,9 @@ func mustTempFile(t *testing.T) (f *os.File, remove func()) {
 	t.Helper()
 
 	base := filepath.Base(t.Name())
-	f, err := ioutil.TempFile("", base)
+	f, err := os.CreateTemp("", base)
 	if err != nil {
-		t.Fatalf(`ioutil.TempFile("", %q) = %v`, base, err)
+		t.Fatalf(`os.CreateTemp("", %q) = %v`, base, err)
 	}
 	t.Logf("fd %d = %s", f.Fd(), f.Name())
 
@@ -161,7 +160,7 @@ func TestRLockExcludesOnlyLock(t *testing.T) {
 
 	doUnlockTF := false
 	switch runtime.GOOS {
-	case "aix", "illumos", "solaris":
+	case "aix", "solaris":
 		// When using POSIX locks (as on Solaris), we can't safely read-lock the
 		// same inode through two different descriptors at the same time: when the
 		// first descriptor is closed, the second descriptor would still be open but

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock_unix.go

@@ -2,12 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd hurd linux netbsd openbsd
+// +build darwin dragonfly freebsd hurd illumos linux netbsd openbsd
 
 package filelock
 
 import (
-	"os"
+	"io/fs"
 	"syscall"
 )
 
@@ -26,7 +26,7 @@ func lock(f File, lt lockType) (err error) {
 		}
 	}
 	if err != nil {
-		return &os.PathError{
+		return &fs.PathError{
 			Op:   lt.String(),
 			Path: f.Name(),
 			Err:  err,

libgo/go/cmd/go/internal/lockedfile/internal/filelock/filelock_windows.go

@@ -8,7 +8,7 @@ package filelock
 
 import (
 	"internal/syscall/windows"
-	"os"
+	"io/fs"
 	"syscall"
 )
 
@@ -34,7 +34,7 @@ func lock(f File, lt lockType) error {
 
 	err := windows.LockFileEx(syscall.Handle(f.Fd()), uint32(lt), reserved, allBytes, allBytes, ol)
 	if err != nil {
-		return &os.PathError{
+		return &fs.PathError{
 			Op:   lt.String(),
 			Path: f.Name(),
 			Err:  err,
@@ -47,7 +47,7 @@ func unlock(f File) error {
 	ol := new(syscall.Overlapped)
 	err := windows.UnlockFileEx(syscall.Handle(f.Fd()), reserved, allBytes, allBytes, ol)
 	if err != nil {
-		return &os.PathError{
+		return &fs.PathError{
 			Op:   "Unlock",
 			Path: f.Name(),
 			Err:  err,

libgo/go/cmd/go/internal/lockedfile/lockedfile.go

@@ -9,7 +9,7 @@ package lockedfile
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"runtime"
 )
@@ -35,7 +35,7 @@ type osFile struct {
 // OpenFile is like os.OpenFile, but returns a locked file.
 // If flag includes os.O_WRONLY or os.O_RDWR, the file is write-locked;
 // otherwise, it is read-locked.
-func OpenFile(name string, flag int, perm os.FileMode) (*File, error) {
+func OpenFile(name string, flag int, perm fs.FileMode) (*File, error) {
 	var (
 		f   = new(File)
 		err error
@@ -82,10 +82,10 @@ func Edit(name string) (*File, error) {
 // non-nil error.
 func (f *File) Close() error {
 	if f.closed {
-		return &os.PathError{
+		return &fs.PathError{
 			Op:   "close",
 			Path: f.Name(),
-			Err:  os.ErrClosed,
+			Err:  fs.ErrClosed,
 		}
 	}
 	f.closed = true
@@ -103,12 +103,12 @@ func Read(name string) ([]byte, error) {
 	}
 	defer f.Close()
 
-	return ioutil.ReadAll(f)
+	return io.ReadAll(f)
 }
 
 // Write opens the named file (creating it with the given permissions if needed),
 // then write-locks it and overwrites it with the given content.
-func Write(name string, content io.Reader, perm os.FileMode) (err error) {
+func Write(name string, content io.Reader, perm fs.FileMode) (err error) {
 	f, err := OpenFile(name, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
 	if err != nil {
 		return err
@@ -135,7 +135,7 @@ func Transform(name string, t func([]byte) ([]byte, error)) (err error) {
 	}
 	defer f.Close()
 
-	old, err := ioutil.ReadAll(f)
+	old, err := io.ReadAll(f)
 	if err != nil {
 		return err
 	}

libgo/go/cmd/go/internal/lockedfile/lockedfile_filelock.go

@@ -7,18 +7,20 @@
 package lockedfile
 
 import (
+	"io/fs"
 	"os"
 
+	"cmd/go/internal/fsys"
 	"cmd/go/internal/lockedfile/internal/filelock"
 )
 
-func openFile(name string, flag int, perm os.FileMode) (*os.File, error) {
+func openFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
 	// On BSD systems, we could add the O_SHLOCK or O_EXLOCK flag to the OpenFile
 	// call instead of locking separately, but we have to support separate locking
 	// calls for Linux and Windows anyway, so it's simpler to use that approach
 	// consistently.
 
-	f, err := os.OpenFile(name, flag&^os.O_TRUNC, perm)
+	f, err := fsys.OpenFile(name, flag&^os.O_TRUNC, perm)
 	if err != nil {
 		return nil, err
 	}

libgo/go/cmd/go/internal/lockedfile/lockedfile_plan9.go

@@ -7,10 +7,13 @@
 package lockedfile
 
 import (
+	"io/fs"
 	"math/rand"
 	"os"
 	"strings"
 	"time"
+
+	"cmd/go/internal/fsys"
 )
 
 // Opening an exclusive-use file returns an error.
@@ -41,7 +44,7 @@ func isLocked(err error) bool {
 	return false
 }
 
-func openFile(name string, flag int, perm os.FileMode) (*os.File, error) {
+func openFile(name string, flag int, perm fs.FileMode) (*os.File, error) {
 	// Plan 9 uses a mode bit instead of explicit lock/unlock syscalls.
 	//
 	// Per http://man.cat-v.org/plan_9/5/stat: “Exclusive use files may be open
@@ -55,9 +58,9 @@ func openFile(name string, flag int, perm os.FileMode) (*os.File, error) {
 	// If the file was unpacked or created by some other program, it might not
 	// have the ModeExclusive bit set. Set it before we call OpenFile, so that we
 	// can be confident that a successful OpenFile implies exclusive use.
-	if fi, err := os.Stat(name); err == nil {
+	if fi, err := fsys.Stat(name); err == nil {
-		if fi.Mode()&os.ModeExclusive == 0 {
+		if fi.Mode()&fs.ModeExclusive == 0 {
-			if err := os.Chmod(name, fi.Mode()|os.ModeExclusive); err != nil {
+			if err := os.Chmod(name, fi.Mode()|fs.ModeExclusive); err != nil {
 				return nil, err
 			}
 		}
@@ -68,7 +71,7 @@ func openFile(name string, flag int, perm os.FileMode) (*os.File, error) {
 	nextSleep := 1 * time.Millisecond
 	const maxSleep = 500 * time.Millisecond
 	for {
-		f, err := os.OpenFile(name, flag, perm|os.ModeExclusive)
+		f, err := fsys.OpenFile(name, flag, perm|fs.ModeExclusive)
 		if err == nil {
 			return f, nil
 		}

libgo/go/cmd/go/internal/lockedfile/lockedfile_test.go

@@ -10,7 +10,6 @@ package lockedfile_test
 import (
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -23,7 +22,7 @@ import (
 func mustTempDir(t *testing.T) (dir string, remove func()) {
 	t.Helper()
 
-	dir, err := ioutil.TempDir("", filepath.Base(t.Name()))
+	dir, err := os.MkdirTemp("", filepath.Base(t.Name()))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -155,8 +154,8 @@ func TestCanLockExistingFile(t *testing.T) {
 	defer remove()
 	path := filepath.Join(dir, "existing.txt")
 
-	if err := ioutil.WriteFile(path, []byte("ok"), 0777); err != nil {
+	if err := os.WriteFile(path, []byte("ok"), 0777); err != nil {
-		t.Fatalf("ioutil.WriteFile: %v", err)
+		t.Fatalf("os.WriteFile: %v", err)
 	}
 
 	f, err := lockedfile.Edit(path)
@@ -201,7 +200,7 @@ func TestSpuriousEDEADLK(t *testing.T) {
 		}
 		defer b.Close()
 
-		if err := ioutil.WriteFile(filepath.Join(dir, "locked"), []byte("ok"), 0666); err != nil {
+		if err := os.WriteFile(filepath.Join(dir, "locked"), []byte("ok"), 0666); err != nil {
 			t.Fatal(err)
 		}
 

libgo/go/cmd/go/internal/modcmd/download.go

@@ -5,15 +5,15 @@
 package modcmd
 
 import (
+	"context"
 	"encoding/json"
 	"os"
+	"runtime"
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/par"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 )
@@ -63,7 +63,7 @@ func init() {
 
 	// TODO(jayconrod): https://golang.org/issue/35849 Apply -x to other 'go mod' commands.
 	cmdDownload.Flag.BoolVar(&cfg.BuildX, "x", false, "")
-	work.AddModCommonFlags(cmdDownload)
+	base.AddModCommonFlags(&cmdDownload.Flag)
 }
 
 type moduleJSON struct {
@@ -78,56 +78,27 @@ type moduleJSON struct {
 	GoModSum string `json:",omitempty"`
 }
 
-func runDownload(cmd *base.Command, args []string) {
+func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	// Check whether modules are enabled and whether we're in a module.
-	if cfg.Getenv("GO111MODULE") == "off" {
+	modload.ForceUseModules = true
-		base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
-	}
 	if !modload.HasModRoot() && len(args) == 0 {
 		base.Fatalf("go mod download: no modules specified (see 'go help mod download')")
 	}
 	if len(args) == 0 {
 		args = []string{"all"}
 	} else if modload.HasModRoot() {
-		modload.InitMod() // to fill Target
+		modload.LoadModFile(ctx) // to fill Target
-		targetAtLatest := modload.Target.Path + "@latest"
 		targetAtUpgrade := modload.Target.Path + "@upgrade"
 		targetAtPatch := modload.Target.Path + "@patch"
 		for _, arg := range args {
 			switch arg {
-			case modload.Target.Path, targetAtLatest, targetAtUpgrade, targetAtPatch:
+			case modload.Target.Path, targetAtUpgrade, targetAtPatch:
 				os.Stderr.WriteString("go mod download: skipping argument " + arg + " that resolves to the main module\n")
 			}
 		}
 	}
 
-	var mods []*moduleJSON
+	downloadModule := func(m *moduleJSON) {
-	var work par.Work
-	listU := false
-	listVersions := false
-	for _, info := range modload.ListModules(args, listU, listVersions) {
-		if info.Replace != nil {
-			info = info.Replace
-		}
-		if info.Version == "" && info.Error == nil {
-			// main module or module replaced with file path.
-			// Nothing to download.
-			continue
-		}
-		m := &moduleJSON{
-			Path:    info.Path,
-			Version: info.Version,
-		}
-		mods = append(mods, m)
-		if info.Error != nil {
-			m.Error = info.Error.Err
-			continue
-		}
-		work.Add(m)
-	}
-
-	work.Do(10, func(item interface{}) {
-		m := item.(*moduleJSON)
 		var err error
 		m.Info, err = modfetch.InfoFile(m.Path, m.Version)
 		if err != nil {
@@ -145,24 +116,60 @@ func runDownload(cmd *base.Command, args []string) {
 			return
 		}
 		mod := module.Version{Path: m.Path, Version: m.Version}
-		m.Zip, err = modfetch.DownloadZip(mod)
+		m.Zip, err = modfetch.DownloadZip(ctx, mod)
 		if err != nil {
 			m.Error = err.Error()
 			return
 		}
 		m.Sum = modfetch.Sum(mod)
-		m.Dir, err = modfetch.Download(mod)
+		m.Dir, err = modfetch.Download(ctx, mod)
 		if err != nil {
 			m.Error = err.Error()
 			return
 		}
-	})
+	}
+
+	var mods []*moduleJSON
+	listU := false
+	listVersions := false
+	listRetractions := false
+	type token struct{}
+	sem := make(chan token, runtime.GOMAXPROCS(0))
+	for _, info := range modload.ListModules(ctx, args, listU, listVersions, listRetractions) {
+		if info.Replace != nil {
+			info = info.Replace
+		}
+		if info.Version == "" && info.Error == nil {
+			// main module or module replaced with file path.
+			// Nothing to download.
+			continue
+		}
+		m := &moduleJSON{
+			Path:    info.Path,
+			Version: info.Version,
+		}
+		mods = append(mods, m)
+		if info.Error != nil {
+			m.Error = info.Error.Err
+			continue
+		}
+		sem <- token{}
+		go func() {
+			downloadModule(m)
+			<-sem
+		}()
+	}
+
+	// Fill semaphore channel to wait for goroutines to finish.
+	for n := cap(sem); n > 0; n-- {
+		sem <- token{}
+	}
 
 	if *downloadJSON {
 		for _, m := range mods {
 			b, err := json.MarshalIndent(m, "", "\t")
 			if err != nil {
-				base.Fatalf("%v", err)
+				base.Fatalf("go mod download: %v", err)
 			}
 			os.Stdout.Write(append(b, '\n'))
 			if m.Error != "" {
@@ -172,9 +179,12 @@ func runDownload(cmd *base.Command, args []string) {
 	} else {
 		for _, m := range mods {
 			if m.Error != "" {
-				base.Errorf("%s", m.Error)
+				base.Errorf("go mod download: %v", m.Error)
 			}
 		}
 		base.ExitIfErrors()
 	}
+
+	// Update go.mod and especially go.sum if needed.
+	modload.WriteGoMod()
 }

libgo/go/cmd/go/internal/modcmd/edit.go

@@ -8,6 +8,7 @@ package modcmd
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -18,7 +19,6 @@ import (
 	"cmd/go/internal/lockedfile"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/modfile"
 	"golang.org/x/mod/module"
@@ -67,9 +67,14 @@ The -dropreplace=old[@v] flag drops a replacement of the given
 module path and version pair. If the @v is omitted, a replacement without
 a version on the left side is dropped.
 
+The -retract=version and -dropretract=version flags add and drop a
+retraction on the given version. The version may be a single version
+like "v1.2.3" or a closed interval like "[v1.1.0,v1.1.9]". Note that
+-retract=version is a no-op if that retraction already exists.
+
 The -require, -droprequire, -exclude, -dropexclude, -replace,
-and -dropreplace editing flags may be repeated, and the changes
+-dropreplace, -retract, and -dropretract editing flags may be repeated,
-are applied in the order given.
+and the changes are applied in the order given.
 
 The -go=version flag sets the expected Go language version.
 
@@ -103,6 +108,15 @@ writing it back to go.mod. The JSON output corresponds to these Go types:
 		New Module
 	}
 
+	type Retract struct {
+		Low       string
+		High      string
+		Rationale string
+	}
+
+Retract entries representing a single version (not an interval) will have
+the "Low" and "High" fields set to the same value.
+
 Note that this only describes the go.mod file itself, not other modules
 referred to indirectly. For the full set of modules available to a build,
 use 'go list -m -json all'.
@@ -136,12 +150,14 @@ func init() {
 	cmdEdit.Flag.Var(flagFunc(flagDropReplace), "dropreplace", "")
 	cmdEdit.Flag.Var(flagFunc(flagReplace), "replace", "")
 	cmdEdit.Flag.Var(flagFunc(flagDropExclude), "dropexclude", "")
+	cmdEdit.Flag.Var(flagFunc(flagRetract), "retract", "")
+	cmdEdit.Flag.Var(flagFunc(flagDropRetract), "dropretract", "")
 
-	work.AddModCommonFlags(cmdEdit)
+	base.AddModCommonFlags(&cmdEdit.Flag)
 	base.AddBuildFlagsNX(&cmdEdit.Flag)
 }
 
-func runEdit(cmd *base.Command, args []string) {
+func runEdit(ctx context.Context, cmd *base.Command, args []string) {
 	anyFlags :=
 		*editModule != "" ||
 			*editGo != "" ||
@@ -251,12 +267,7 @@ func parsePathVersion(flag, arg string) (path, version string) {
 		base.Fatalf("go mod: -%s=%s: invalid path: %v", flag, arg, err)
 	}
 
-	// We don't call modfile.CheckPathVersion, because that insists
+	if !allowedVersionArg(version) {
-	// on versions being in semver form, but here we want to allow
-	// versions like "master" or "1234abcdef", which the go command will resolve
-	// the next time it runs (or during -fix).
-	// Even so, we need to make sure the version is a valid token.
-	if modfile.MustQuote(version) {
 		base.Fatalf("go mod: -%s=%s: invalid version %q", flag, arg, version)
 	}
 
@@ -288,12 +299,48 @@ func parsePathVersionOptional(adj, arg string, allowDirPath bool) (path, version
 			return path, version, fmt.Errorf("invalid %s path: %v", adj, err)
 		}
 	}
-	if path != arg && modfile.MustQuote(version) {
+	if path != arg && !allowedVersionArg(version) {
 		return path, version, fmt.Errorf("invalid %s version: %q", adj, version)
 	}
 	return path, version, nil
 }
 
+// parseVersionInterval parses a single version like "v1.2.3" or a closed
+// interval like "[v1.2.3,v1.4.5]". Note that a single version has the same
+// representation as an interval with equal upper and lower bounds: both
+// Low and High are set.
+func parseVersionInterval(arg string) (modfile.VersionInterval, error) {
+	if !strings.HasPrefix(arg, "[") {
+		if !allowedVersionArg(arg) {
+			return modfile.VersionInterval{}, fmt.Errorf("invalid version: %q", arg)
+		}
+		return modfile.VersionInterval{Low: arg, High: arg}, nil
+	}
+	if !strings.HasSuffix(arg, "]") {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	s := arg[1 : len(arg)-1]
+	i := strings.Index(s, ",")
+	if i < 0 {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	low := strings.TrimSpace(s[:i])
+	high := strings.TrimSpace(s[i+1:])
+	if !allowedVersionArg(low) || !allowedVersionArg(high) {
+		return modfile.VersionInterval{}, fmt.Errorf("invalid version interval: %q", arg)
+	}
+	return modfile.VersionInterval{Low: low, High: high}, nil
+}
+
+// allowedVersionArg returns whether a token may be used as a version in go.mod.
+// We don't call modfile.CheckPathVersion, because that insists on versions
+// being in semver form, but here we want to allow versions like "master" or
+// "1234abcdef", which the go command will resolve the next time it runs (or
+// during -fix).  Even so, we need to make sure the version is a valid token.
+func allowedVersionArg(arg string) bool {
+	return !modfile.MustQuote(arg)
+}
+
 // flagRequire implements the -require flag.
 func flagRequire(arg string) {
 	path, version := parsePathVersion("require", arg)
@@ -376,6 +423,32 @@ func flagDropReplace(arg string) {
 	})
 }
 
+// flagRetract implements the -retract flag.
+func flagRetract(arg string) {
+	vi, err := parseVersionInterval(arg)
+	if err != nil {
+		base.Fatalf("go mod: -retract=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.AddRetract(vi, ""); err != nil {
+			base.Fatalf("go mod: -retract=%s: %v", arg, err)
+		}
+	})
+}
+
+// flagDropRetract implements the -dropretract flag.
+func flagDropRetract(arg string) {
+	vi, err := parseVersionInterval(arg)
+	if err != nil {
+		base.Fatalf("go mod: -dropretract=%s: %v", arg, err)
+	}
+	edits = append(edits, func(f *modfile.File) {
+		if err := f.DropRetract(vi); err != nil {
+			base.Fatalf("go mod: -dropretract=%s: %v", arg, err)
+		}
+	})
+}
+
 // fileJSON is the -json output data structure.
 type fileJSON struct {
 	Module  module.Version
@@ -383,6 +456,7 @@ type fileJSON struct {
 	Require []requireJSON
 	Exclude []module.Version
 	Replace []replaceJSON
+	Retract []retractJSON
 }
 
 type requireJSON struct {
@@ -396,6 +470,12 @@ type replaceJSON struct {
 	New module.Version
 }
 
+type retractJSON struct {
+	Low       string `json:",omitempty"`
+	High      string `json:",omitempty"`
+	Rationale string `json:",omitempty"`
+}
+
 // editPrintJSON prints the -json output.
 func editPrintJSON(modFile *modfile.File) {
 	var f fileJSON
@@ -414,6 +494,9 @@ func editPrintJSON(modFile *modfile.File) {
 	for _, r := range modFile.Replace {
 		f.Replace = append(f.Replace, replaceJSON{r.Old, r.New})
 	}
+	for _, r := range modFile.Retract {
+		f.Retract = append(f.Retract, retractJSON{r.Low, r.High, r.Rationale})
+	}
 	data, err := json.MarshalIndent(&f, "", "\t")
 	if err != nil {
 		base.Fatalf("go: internal error: %v", err)

libgo/go/cmd/go/internal/modcmd/graph.go

@@ -8,14 +8,12 @@ package modcmd
 
 import (
 	"bufio"
+	"context"
 	"os"
 	"sort"
 
 	"cmd/go/internal/base"
-	"cmd/go/internal/cfg"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/par"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 )
@@ -33,22 +31,16 @@ path@version, except for the main module, which has no @version suffix.
 }
 
 func init() {
-	work.AddModCommonFlags(cmdGraph)
+	base.AddModCommonFlags(&cmdGraph.Flag)
 }
 
-func runGraph(cmd *base.Command, args []string) {
+func runGraph(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) > 0 {
 		base.Fatalf("go mod graph: graph takes no arguments")
 	}
-	// Checks go mod expected behavior
+	modload.ForceUseModules = true
-	if !modload.Enabled() {
+	modload.RootMode = modload.NeedRoot
-		if cfg.Getenv("GO111MODULE") == "off" {
+	modload.LoadAllModules(ctx)
-			base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
-		} else {
-			base.Fatalf("go: cannot find main module; see 'go help modules'")
-		}
-	}
-	modload.LoadBuildList()
 
 	reqs := modload.MinReqs()
 	format := func(m module.Version) string {
@@ -58,23 +50,25 @@ func runGraph(cmd *base.Command, args []string) {
 		return m.Path + "@" + m.Version
 	}
 
-	// Note: using par.Work only to manage work queue.
-	// No parallelism here, so no locking.
 	var out []string
 	var deps int // index in out where deps start
-	var work par.Work
+	seen := map[module.Version]bool{modload.Target: true}
-	work.Add(modload.Target)
+	queue := []module.Version{modload.Target}
-	work.Do(1, func(item interface{}) {
+	for len(queue) > 0 {
-		m := item.(module.Version)
+		var m module.Version
+		m, queue = queue[0], queue[1:]
 		list, _ := reqs.Required(m)
 		for _, r := range list {
-			work.Add(r)
+			if !seen[r] {
+				queue = append(queue, r)
+				seen[r] = true
+			}
 			out = append(out, format(m)+" "+format(r)+"\n")
 		}
 		if m == modload.Target {
 			deps = len(out)
 		}
-	})
+	}
 
 	sort.Slice(out[deps:], func(i, j int) bool {
 		return out[deps+i][0] < out[deps+j][0]

libgo/go/cmd/go/internal/modcmd/init.go

@@ -9,46 +9,41 @@ package modcmd
 import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
+	"context"
-	"os"
-	"strings"
 )
 
 var cmdInit = &base.Command{
 	UsageLine: "go mod init [module]",
 	Short:     "initialize new module in current directory",
 	Long: `
-Init initializes and writes a new go.mod to the current directory,
+Init initializes and writes a new go.mod file in the current directory, in
-in effect creating a new module rooted at the current directory.
+effect creating a new module rooted at the current directory. The go.mod file
-The file go.mod must not already exist.
+must not already exist.
-If possible, init will guess the module path from import comments
+
-(see 'go help importpath') or from version control configuration.
+Init accepts one optional argument, the module path for the new module. If the
-To override this guess, supply the module path as an argument.
+module path argument is omitted, init will attempt to infer the module path
-	`,
+using import comments in .go files, vendoring tool configuration files (like
+Gopkg.lock), and the current directory (if in GOPATH).
+
+If a configuration file for a vendoring tool is present, init will attempt to
+import module requirements from it.
+`,
 	Run: runInit,
 }
 
 func init() {
-	work.AddModCommonFlags(cmdInit)
+	base.AddModCommonFlags(&cmdInit.Flag)
 }
 
-func runInit(cmd *base.Command, args []string) {
+func runInit(ctx context.Context, cmd *base.Command, args []string) {
-	modload.CmdModInit = true
 	if len(args) > 1 {
 		base.Fatalf("go mod init: too many arguments")
 	}
+	var modPath string
 	if len(args) == 1 {
-		modload.CmdModModule = args[0]
+		modPath = args[0]
 	}
-	if os.Getenv("GO111MODULE") == "off" {
+
-		base.Fatalf("go mod init: modules disabled by GO111MODULE=off; see 'go help modules'")
+	modload.ForceUseModules = true
-	}
+	modload.CreateModFile(ctx, modPath) // does all the hard work
-	modFilePath := modload.ModFilePath()
-	if _, err := os.Stat(modFilePath); err == nil {
-		base.Fatalf("go mod init: go.mod already exists")
-	}
-	if strings.Contains(modload.CmdModModule, "@") {
-		base.Fatalf("go mod init: module path must not contain '@'")
-	}
-	modload.InitMod() // does all the hard work
 }

libgo/go/cmd/go/internal/modcmd/tidy.go

@@ -9,15 +9,13 @@ package modcmd
 import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
-	"cmd/go/internal/modfetch"
+	"cmd/go/internal/imports"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
+	"context"
-
-	"golang.org/x/mod/module"
 )
 
 var cmdTidy = &base.Command{
-	UsageLine: "go mod tidy [-v]",
+	UsageLine: "go mod tidy [-e] [-v]",
 	Short:     "add missing and remove unused modules",
 	Long: `
 Tidy makes sure go.mod matches the source code in the module.
@@ -28,55 +26,47 @@ to go.sum and removes any unnecessary ones.
 
 The -v flag causes tidy to print information about removed modules
 to standard error.
+
+The -e flag causes tidy to attempt to proceed despite errors
+encountered while loading packages.
 	`,
+	Run: runTidy,
 }
 
+var tidyE bool // if true, report errors but proceed anyway.
+
 func init() {
-	cmdTidy.Run = runTidy // break init cycle
 	cmdTidy.Flag.BoolVar(&cfg.BuildV, "v", false, "")
-	work.AddModCommonFlags(cmdTidy)
+	cmdTidy.Flag.BoolVar(&tidyE, "e", false, "")
+	base.AddModCommonFlags(&cmdTidy.Flag)
 }
 
-func runTidy(cmd *base.Command, args []string) {
+func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) > 0 {
 		base.Fatalf("go mod tidy: no arguments allowed")
 	}
 
-	modload.LoadALL()
+	// Tidy aims to make 'go test' reproducible for any package in 'all', so we
+	// need to include test dependencies. For modules that specify go 1.15 or
+	// earlier this is a no-op (because 'all' saturates transitive test
+	// dependencies).
+	//
+	// However, with lazy loading (go 1.16+) 'all' includes only the packages that
+	// are transitively imported by the main module, not the test dependencies of
+	// those packages. In order to make 'go test' reproducible for the packages
+	// that are in 'all' but outside of the main module, we must explicitly
+	// request that their test dependencies be included.
+	modload.ForceUseModules = true
+	modload.RootMode = modload.NeedRoot
+
+	modload.LoadPackages(ctx, modload.PackageOpts{
+		Tags:                  imports.AnyTags(),
+		ResolveMissingImports: true,
+		LoadTests:             true,
+		AllowErrors:           tidyE,
+	}, "all")
+
 	modload.TidyBuildList()
-	modTidyGoSum() // updates memory copy; WriteGoMod on next line flushes it out
+	modload.TrimGoSum()
 	modload.WriteGoMod()
 }
-
-// modTidyGoSum resets the go.sum file content
-// to be exactly what's needed for the current go.mod.
-func modTidyGoSum() {
-	// Assuming go.sum already has at least enough from the successful load,
-	// we only have to tell modfetch what needs keeping.
-	reqs := modload.Reqs()
-	keep := make(map[module.Version]bool)
-	replaced := make(map[module.Version]bool)
-	var walk func(module.Version)
-	walk = func(m module.Version) {
-		// If we build using a replacement module, keep the sum for the replacement,
-		// since that's the code we'll actually use during a build.
-		//
-		// TODO(golang.org/issue/29182): Perhaps we should keep both sums, and the
-		// sums for both sets of transitive requirements.
-		r := modload.Replacement(m)
-		if r.Path == "" {
-			keep[m] = true
-		} else {
-			keep[r] = true
-			replaced[m] = true
-		}
-		list, _ := reqs.Required(m)
-		for _, r := range list {
-			if !keep[r] && !replaced[r] {
-				walk(r)
-			}
-		}
-	}
-	walk(modload.Target)
-	modfetch.TrimGoSum(keep)
-}

libgo/go/cmd/go/internal/modcmd/vendor.go

@@ -6,9 +6,10 @@ package modcmd
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"sort"
@@ -16,16 +17,16 @@ import (
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
+	"cmd/go/internal/fsys"
 	"cmd/go/internal/imports"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 	"golang.org/x/mod/semver"
 )
 
 var cmdVendor = &base.Command{
-	UsageLine: "go mod vendor [-v]",
+	UsageLine: "go mod vendor [-e] [-v]",
 	Short:     "make vendored copy of dependencies",
 	Long: `
 Vendor resets the main module's vendor directory to include all packages
@@ -34,20 +35,35 @@ It does not include test code for vendored packages.
 
 The -v flag causes vendor to print the names of vendored
 modules and packages to standard error.
+
+The -e flag causes vendor to attempt to proceed despite errors
+encountered while loading packages.
 	`,
 	Run: runVendor,
 }
 
+var vendorE bool // if true, report errors but proceed anyway
+
 func init() {
 	cmdVendor.Flag.BoolVar(&cfg.BuildV, "v", false, "")
-	work.AddModCommonFlags(cmdVendor)
+	cmdVendor.Flag.BoolVar(&vendorE, "e", false, "")
+	base.AddModCommonFlags(&cmdVendor.Flag)
 }
 
-func runVendor(cmd *base.Command, args []string) {
+func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) != 0 {
 		base.Fatalf("go mod vendor: vendor takes no arguments")
 	}
-	pkgs := modload.LoadVendor()
+	modload.ForceUseModules = true
+	modload.RootMode = modload.NeedRoot
+
+	loadOpts := modload.PackageOpts{
+		Tags:                  imports.AnyTags(),
+		ResolveMissingImports: true,
+		UseVendorAll:          true,
+		AllowErrors:           vendorE,
+	}
+	_, pkgs := modload.LoadPackages(ctx, loadOpts, "all")
 
 	vdir := filepath.Join(modload.ModRoot(), "vendor")
 	if err := os.RemoveAll(vdir); err != nil {
@@ -57,7 +73,7 @@ func runVendor(cmd *base.Command, args []string) {
 	modpkgs := make(map[module.Version][]string)
 	for _, pkg := range pkgs {
 		m := modload.PackageModule(pkg)
-		if m == modload.Target {
+		if m.Path == "" || m == modload.Target {
 			continue
 		}
 		modpkgs[m] = append(modpkgs[m], pkg)
@@ -75,28 +91,38 @@ func runVendor(cmd *base.Command, args []string) {
 		includeAllReplacements = true
 	}
 
+	var vendorMods []module.Version
+	for m := range isExplicit {
+		vendorMods = append(vendorMods, m)
+	}
+	for m := range modpkgs {
+		if !isExplicit[m] {
+			vendorMods = append(vendorMods, m)
+		}
+	}
+	module.Sort(vendorMods)
+
 	var buf bytes.Buffer
-	for _, m := range modload.BuildList()[1:] {
+	for _, m := range vendorMods {
-		if pkgs := modpkgs[m]; len(pkgs) > 0 || isExplicit[m] {
+		line := moduleLine(m, modload.Replacement(m))
-			line := moduleLine(m, modload.Replacement(m))
+		buf.WriteString(line)
-			buf.WriteString(line)
+		if cfg.BuildV {
+			os.Stderr.WriteString(line)
+		}
+		if isExplicit[m] {
+			buf.WriteString("## explicit\n")
 			if cfg.BuildV {
-				os.Stderr.WriteString(line)
+				os.Stderr.WriteString("## explicit\n")
 			}
-			if isExplicit[m] {
+		}
-				buf.WriteString("## explicit\n")
+		pkgs := modpkgs[m]
-				if cfg.BuildV {
+		sort.Strings(pkgs)
-					os.Stderr.WriteString("## explicit\n")
+		for _, pkg := range pkgs {
-				}
+			fmt.Fprintf(&buf, "%s\n", pkg)
-			}
+			if cfg.BuildV {
-			sort.Strings(pkgs)
+				fmt.Fprintf(os.Stderr, "%s\n", pkg)
-			for _, pkg := range pkgs {
-				fmt.Fprintf(&buf, "%s\n", pkg)
-				if cfg.BuildV {
-					fmt.Fprintf(os.Stderr, "%s\n", pkg)
-				}
-				vendorPkg(vdir, pkg)
 			}
+			vendorPkg(vdir, pkg)
 		}
 	}
 
@@ -128,7 +154,7 @@ func runVendor(cmd *base.Command, args []string) {
 		base.Fatalf("go mod vendor: %v", err)
 	}
 
-	if err := ioutil.WriteFile(filepath.Join(vdir, "modules.txt"), buf.Bytes(), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(vdir, "modules.txt"), buf.Bytes(), 0666); err != nil {
 		base.Fatalf("go mod vendor: %v", err)
 	}
 }
@@ -217,7 +243,7 @@ var metaPrefixes = []string{
 }
 
 // matchMetadata reports whether info is a metadata file.
-func matchMetadata(dir string, info os.FileInfo) bool {
+func matchMetadata(dir string, info fs.DirEntry) bool {
 	name := info.Name()
 	for _, p := range metaPrefixes {
 		if strings.HasPrefix(name, p) {
@@ -228,12 +254,12 @@ func matchMetadata(dir string, info os.FileInfo) bool {
 }
 
 // matchPotentialSourceFile reports whether info may be relevant to a build operation.
-func matchPotentialSourceFile(dir string, info os.FileInfo) bool {
+func matchPotentialSourceFile(dir string, info fs.DirEntry) bool {
 	if strings.HasSuffix(info.Name(), "_test.go") {
 		return false
 	}
 	if strings.HasSuffix(info.Name(), ".go") {
-		f, err := os.Open(filepath.Join(dir, info.Name()))
+		f, err := fsys.Open(filepath.Join(dir, info.Name()))
 		if err != nil {
 			base.Fatalf("go mod vendor: %v", err)
 		}
@@ -254,8 +280,8 @@ func matchPotentialSourceFile(dir string, info os.FileInfo) bool {
 }
 
 // copyDir copies all regular files satisfying match(info) from src to dst.
-func copyDir(dst, src string, match func(dir string, info os.FileInfo) bool) {
+func copyDir(dst, src string, match func(dir string, info fs.DirEntry) bool) {
-	files, err := ioutil.ReadDir(src)
+	files, err := os.ReadDir(src)
 	if err != nil {
 		base.Fatalf("go mod vendor: %v", err)
 	}
@@ -263,7 +289,7 @@ func copyDir(dst, src string, match func(dir string, info os.FileInfo) bool) {
 		base.Fatalf("go mod vendor: %v", err)
 	}
 	for _, file := range files {
-		if file.IsDir() || !file.Mode().IsRegular() || !match(src, file) {
+		if file.IsDir() || !file.Type().IsRegular() || !match(src, file) {
 			continue
 		}
 		r, err := os.Open(filepath.Join(src, file.Name()))

libgo/go/cmd/go/internal/modcmd/verify.go

@@ -6,17 +6,16 @@ package modcmd
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"runtime"
 
 	"cmd/go/internal/base"
-	"cmd/go/internal/cfg"
 	"cmd/go/internal/modfetch"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 	"golang.org/x/mod/sumdb/dirhash"
@@ -37,29 +36,23 @@ non-zero status.
 }
 
 func init() {
-	work.AddModCommonFlags(cmdVerify)
+	base.AddModCommonFlags(&cmdVerify.Flag)
 }
 
-func runVerify(cmd *base.Command, args []string) {
+func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) != 0 {
 		// NOTE(rsc): Could take a module pattern.
 		base.Fatalf("go mod verify: verify takes no arguments")
 	}
-	// Checks go mod expected behavior
+	modload.ForceUseModules = true
-	if !modload.Enabled() || !modload.HasModRoot() {
+	modload.RootMode = modload.NeedRoot
-		if cfg.Getenv("GO111MODULE") == "off" {
-			base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
-		} else {
-			base.Fatalf("go: cannot find main module; see 'go help modules'")
-		}
-	}
 
 	// Only verify up to GOMAXPROCS zips at once.
 	type token struct{}
 	sem := make(chan token, runtime.GOMAXPROCS(0))
 
 	// Use a slice of result channels, so that the output is deterministic.
-	mods := modload.LoadBuildList()[1:]
+	mods := modload.LoadAllModules(ctx)[1:]
 	errsChans := make([]<-chan []error, len(mods))
 
 	for i, mod := range mods {
@@ -93,10 +86,10 @@ func verifyMod(mod module.Version) []error {
 		_, zipErr = os.Stat(zip)
 	}
 	dir, dirErr := modfetch.DownloadDir(mod)
-	data, err := ioutil.ReadFile(zip + "hash")
+	data, err := os.ReadFile(zip + "hash")
 	if err != nil {
-		if zipErr != nil && errors.Is(zipErr, os.ErrNotExist) &&
+		if zipErr != nil && errors.Is(zipErr, fs.ErrNotExist) &&
-			dirErr != nil && errors.Is(dirErr, os.ErrNotExist) {
+			dirErr != nil && errors.Is(dirErr, fs.ErrNotExist) {
 			// Nothing downloaded yet. Nothing to verify.
 			return nil
 		}
@@ -105,7 +98,7 @@ func verifyMod(mod module.Version) []error {
 	}
 	h := string(bytes.TrimSpace(data))
 
-	if zipErr != nil && errors.Is(zipErr, os.ErrNotExist) {
+	if zipErr != nil && errors.Is(zipErr, fs.ErrNotExist) {
 		// ok
 	} else {
 		hZ, err := dirhash.HashZip(zip, dirhash.DefaultHash)
@@ -116,7 +109,7 @@ func verifyMod(mod module.Version) []error {
 			errs = append(errs, fmt.Errorf("%s %s: zip has been modified (%v)", mod.Path, mod.Version, zip))
 		}
 	}
-	if dirErr != nil && errors.Is(dirErr, os.ErrNotExist) {
+	if dirErr != nil && errors.Is(dirErr, fs.ErrNotExist) {
 		// ok
 	} else {
 		hD, err := dirhash.HashDir(dir, mod.Path+"@"+mod.Version, dirhash.DefaultHash)

libgo/go/cmd/go/internal/modcmd/why.go

@@ -5,12 +5,13 @@
 package modcmd
 
 import (
+	"context"
 	"fmt"
 	"strings"
 
 	"cmd/go/internal/base"
+	"cmd/go/internal/imports"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 
 	"golang.org/x/mod/module"
 )
@@ -57,25 +58,33 @@ var (
 
 func init() {
 	cmdWhy.Run = runWhy // break init cycle
-	work.AddModCommonFlags(cmdWhy)
+	base.AddModCommonFlags(&cmdWhy.Flag)
 }
 
-func runWhy(cmd *base.Command, args []string) {
+func runWhy(ctx context.Context, cmd *base.Command, args []string) {
-	loadALL := modload.LoadALL
+	modload.ForceUseModules = true
-	if *whyVendor {
+	modload.RootMode = modload.NeedRoot
-		loadALL = modload.LoadVendor
+
+	loadOpts := modload.PackageOpts{
+		Tags:          imports.AnyTags(),
+		LoadTests:     !*whyVendor,
+		SilenceErrors: true,
+		UseVendorAll:  *whyVendor,
 	}
+
 	if *whyM {
 		listU := false
 		listVersions := false
+		listRetractions := false
 		for _, arg := range args {
 			if strings.Contains(arg, "@") {
 				base.Fatalf("go mod why: module query not allowed")
 			}
 		}
-		mods := modload.ListModules(args, listU, listVersions)
+		mods := modload.ListModules(ctx, args, listU, listVersions, listRetractions)
 		byModule := make(map[module.Version][]string)
-		for _, path := range loadALL() {
+		_, pkgs := modload.LoadPackages(ctx, loadOpts, "all")
+		for _, path := range pkgs {
 			m := modload.PackageModule(path)
 			if m.Path != "" {
 				byModule[m] = append(byModule[m], path)
@@ -104,8 +113,11 @@ func runWhy(cmd *base.Command, args []string) {
 			sep = "\n"
 		}
 	} else {
-		matches := modload.ImportPaths(args) // resolve to packages
+		// Resolve to packages.
-		loadALL()                            // rebuild graph, from main module (not from named packages)
+		matches, _ := modload.LoadPackages(ctx, loadOpts, args...)
+
+		modload.LoadPackages(ctx, loadOpts, "all") // rebuild graph, from main module (not from named packages)
+
 		sep := ""
 		for _, m := range matches {
 			for _, path := range m.Pkgs {

libgo/go/cmd/go/internal/modconv/convert.go

@@ -7,13 +7,12 @@ package modconv
 import (
 	"fmt"
 	"os"
+	"runtime"
 	"sort"
 	"strings"
-	"sync"
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/modfetch"
-	"cmd/go/internal/par"
 
 	"golang.org/x/mod/modfile"
 	"golang.org/x/mod/module"
@@ -42,46 +41,54 @@ func ConvertLegacyConfig(f *modfile.File, file string, data []byte) error {
 
 	// Convert requirements block, which may use raw SHA1 hashes as versions,
 	// to valid semver requirement list, respecting major versions.
-	var (
+	versions := make([]module.Version, len(mf.Require))
-		work    par.Work
+	replace := make(map[string]*modfile.Replace)
-		mu      sync.Mutex
-		need    = make(map[string]string)
-		replace = make(map[string]*modfile.Replace)
-	)
 
 	for _, r := range mf.Replace {
 		replace[r.New.Path] = r
 		replace[r.Old.Path] = r
 	}
-	for _, r := range mf.Require {
+
+	type token struct{}
+	sem := make(chan token, runtime.GOMAXPROCS(0))
+	for i, r := range mf.Require {
 		m := r.Mod
 		if m.Path == "" {
 			continue
 		}
 		if re, ok := replace[m.Path]; ok {
-			work.Add(re.New)
+			m = re.New
-			continue
 		}
-		work.Add(r.Mod)
+		sem <- token{}
+		go func(i int, m module.Version) {
+			defer func() { <-sem }()
+			repo, info, err := modfetch.ImportRepoRev(m.Path, m.Version)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "go: converting %s: stat %s@%s: %v\n", base.ShortPath(file), m.Path, m.Version, err)
+				return
+			}
+
+			path := repo.ModulePath()
+			versions[i].Path = path
+			versions[i].Version = info.Version
+		}(i, m)
+	}
+	// Fill semaphore channel to wait for all tasks to finish.
+	for n := cap(sem); n > 0; n-- {
+		sem <- token{}
 	}
 
-	work.Do(10, func(item interface{}) {
+	need := map[string]string{}
-		r := item.(module.Version)
+	for _, v := range versions {
-		repo, info, err := modfetch.ImportRepoRev(r.Path, r.Version)
+		if v.Path == "" {
-		if err != nil {
+			continue
-			fmt.Fprintf(os.Stderr, "go: converting %s: stat %s@%s: %v\n", base.ShortPath(file), r.Path, r.Version, err)
-			return
 		}
-		mu.Lock()
-		path := repo.ModulePath()
 		// Don't use semver.Max here; need to preserve +incompatible suffix.
-		if v, ok := need[path]; !ok || semver.Compare(v, info.Version) < 0 {
+		if needv, ok := need[v.Path]; !ok || semver.Compare(needv, v.Version) < 0 {
-			need[path] = info.Version
+			need[v.Path] = v.Version
 		}
-		mu.Unlock()
+	}
-	})
+	paths := make([]string, 0, len(need))
-
-	var paths []string
 	for path := range need {
 		paths = append(paths, path)
 	}

libgo/go/cmd/go/internal/modconv/convert_test.go

@@ -6,9 +6,9 @@ package modconv
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -36,7 +36,7 @@ func testMain(m *testing.M) int {
 		return 0
 	}
 
-	dir, err := ioutil.TempDir("", "modconv-test-")
+	dir, err := os.MkdirTemp("", "modconv-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -146,6 +146,8 @@ func TestConvertLegacyConfig(t *testing.T) {
 		},
 	}
 
+	ctx := context.Background()
+
 	for _, tt := range tests {
 		t.Run(strings.ReplaceAll(tt.path, "/", "_")+"_"+tt.vers, func(t *testing.T) {
 			f, err := modfile.Parse("golden", []byte(tt.gomod), nil)
@@ -157,14 +159,14 @@ func TestConvertLegacyConfig(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			dir, err := modfetch.Download(module.Version{Path: tt.path, Version: tt.vers})
+			dir, err := modfetch.Download(ctx, module.Version{Path: tt.path, Version: tt.vers})
 			if err != nil {
 				t.Fatal(err)
 			}
 
 			for name := range Converters {
 				file := filepath.Join(dir, name)
-				data, err := ioutil.ReadFile(file)
+				data, err := os.ReadFile(file)
 				if err == nil {
 					f := new(modfile.File)
 					f.AddModuleStmt(tt.path)

libgo/go/cmd/go/internal/modconv/modconv_test.go

@@ -7,7 +7,7 @@ package modconv
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 )
@@ -42,7 +42,7 @@ func Test(t *testing.T) {
 			if Converters[extMap[ext]] == nil {
 				t.Fatalf("Converters[%q] == nil", extMap[ext])
 			}
-			data, err := ioutil.ReadFile(test)
+			data, err := os.ReadFile(test)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -50,7 +50,7 @@ func Test(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			want, err := ioutil.ReadFile(test[:len(test)-len(ext)] + ".out")
+			want, err := os.ReadFile(test[:len(test)-len(ext)] + ".out")
 			if err != nil {
 				t.Error(err)
 			}

libgo/go/cmd/go/internal/modfetch/cache.go

@@ -10,10 +10,11 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
@@ -59,7 +60,7 @@ func CachePath(m module.Version, suffix string) (string, error) {
 
 // DownloadDir returns the directory to which m should have been downloaded.
 // An error will be returned if the module path or version cannot be escaped.
-// An error satisfying errors.Is(err, os.ErrNotExist) will be returned
+// An error satisfying errors.Is(err, fs.ErrNotExist) will be returned
 // along with the directory if the directory does not exist or if the directory
 // is not completely populated.
 func DownloadDir(m module.Version) (string, error) {
@@ -106,14 +107,14 @@ func DownloadDir(m module.Version) (string, error) {
 // DownloadDirPartialError is returned by DownloadDir if a module directory
 // exists but was not completely populated.
 //
-// DownloadDirPartialError is equivalent to os.ErrNotExist.
+// DownloadDirPartialError is equivalent to fs.ErrNotExist.
 type DownloadDirPartialError struct {
 	Dir string
 	Err error
 }
 
 func (e *DownloadDirPartialError) Error() string     { return fmt.Sprintf("%s: %v", e.Dir, e.Err) }
-func (e *DownloadDirPartialError) Is(err error) bool { return err == os.ErrNotExist }
+func (e *DownloadDirPartialError) Is(err error) bool { return err == fs.ErrNotExist }
 
 // lockVersion locks a file within the module cache that guards the downloading
 // and extraction of the zipfile for the given module version.
@@ -155,16 +156,30 @@ func SideLock() (unlock func(), err error) {
 type cachingRepo struct {
 	path  string
 	cache par.Cache // cache for all operations
-	r     Repo
+
+	once     sync.Once
+	initRepo func() (Repo, error)
+	r        Repo
 }
 
-func newCachingRepo(r Repo) *cachingRepo {
+func newCachingRepo(path string, initRepo func() (Repo, error)) *cachingRepo {
 	return &cachingRepo{
-		r:    r,
+		path:     path,
-		path: r.ModulePath(),
+		initRepo: initRepo,
 	}
 }
 
+func (r *cachingRepo) repo() Repo {
+	r.once.Do(func() {
+		var err error
+		r.r, err = r.initRepo()
+		if err != nil {
+			r.r = errRepo{r.path, err}
+		}
+	})
+	return r.r
+}
+
 func (r *cachingRepo) ModulePath() string {
 	return r.path
 }
@@ -175,7 +190,7 @@ func (r *cachingRepo) Versions(prefix string) ([]string, error) {
 		err  error
 	}
 	c := r.cache.Do("versions:"+prefix, func() interface{} {
-		list, err := r.r.Versions(prefix)
+		list, err := r.repo().Versions(prefix)
 		return cached{list, err}
 	}).(cached)
 
@@ -197,7 +212,7 @@ func (r *cachingRepo) Stat(rev string) (*RevInfo, error) {
 			return cachedInfo{info, nil}
 		}
 
-		info, err = r.r.Stat(rev)
+		info, err = r.repo().Stat(rev)
 		if err == nil {
 			// If we resolved, say, 1234abcde to v0.0.0-20180604122334-1234abcdef78,
 			// then save the information under the proper version, for future use.
@@ -224,7 +239,7 @@ func (r *cachingRepo) Stat(rev string) (*RevInfo, error) {
 
 func (r *cachingRepo) Latest() (*RevInfo, error) {
 	c := r.cache.Do("latest:", func() interface{} {
-		info, err := r.r.Latest()
+		info, err := r.repo().Latest()
 
 		// Save info for likely future Stat call.
 		if err == nil {
@@ -258,7 +273,7 @@ func (r *cachingRepo) GoMod(version string) ([]byte, error) {
 			return cached{text, nil}
 		}
 
-		text, err = r.r.GoMod(version)
+		text, err = r.repo().GoMod(version)
 		if err == nil {
 			if err := checkGoMod(r.path, version, text); err != nil {
 				return cached{text, err}
@@ -277,26 +292,11 @@ func (r *cachingRepo) GoMod(version string) ([]byte, error) {
 }
 
 func (r *cachingRepo) Zip(dst io.Writer, version string) error {
-	return r.r.Zip(dst, version)
+	return r.repo().Zip(dst, version)
 }
 
-// Stat is like Lookup(path).Stat(rev) but avoids the
+// InfoFile is like Lookup(path).Stat(version) but returns the name of the file
-// repository path resolution in Lookup if the result is
+// containing the cached information.
-// already cached on local disk.
-func Stat(proxy, path, rev string) (*RevInfo, error) {
-	_, info, err := readDiskStat(path, rev)
-	if err == nil {
-		return info, nil
-	}
-	repo, err := Lookup(proxy, path)
-	if err != nil {
-		return nil, err
-	}
-	return repo.Stat(rev)
-}
-
-// InfoFile is like Stat but returns the name of the file containing
-// the cached information.
 func InfoFile(path, version string) (string, error) {
 	if !semver.IsValid(version) {
 		return "", fmt.Errorf("invalid version %q", version)
@@ -307,10 +307,7 @@ func InfoFile(path, version string) (string, error) {
 	}
 
 	err := TryProxies(func(proxy string) error {
-		repo, err := Lookup(proxy, path)
+		_, err := Lookup(proxy, path).Stat(version)
-		if err == nil {
-			_, err = repo.Stat(version)
-		}
 		return err
 	})
 	if err != nil {
@@ -336,11 +333,7 @@ func GoMod(path, rev string) ([]byte, error) {
 			rev = info.Version
 		} else {
 			err := TryProxies(func(proxy string) error {
-				repo, err := Lookup(proxy, path)
+				info, err := Lookup(proxy, path).Stat(rev)
-				if err != nil {
-					return err
-				}
-				info, err := repo.Stat(rev)
 				if err == nil {
 					rev = info.Version
 				}
@@ -357,11 +350,8 @@ func GoMod(path, rev string) ([]byte, error) {
 		return data, nil
 	}
 
-	err = TryProxies(func(proxy string) error {
+	err = TryProxies(func(proxy string) (err error) {
-		repo, err := Lookup(proxy, path)
+		data, err = Lookup(proxy, path).GoMod(rev)
-		if err == nil {
-			data, err = repo.GoMod(rev)
-		}
 		return err
 	})
 	return data, err
@@ -492,7 +482,7 @@ func readDiskStatByHash(path, rev string) (file string, info *RevInfo, err error
 	for _, name := range names {
 		if strings.HasSuffix(name, suffix) {
 			v := strings.TrimSuffix(name, ".info")
-			if IsPseudoVersion(v) && semver.Max(maxVersion, v) == v {
+			if IsPseudoVersion(v) && semver.Compare(v, maxVersion) > 0 {
 				maxVersion = v
 				file, info, err = readDiskStat(path, strings.TrimSuffix(name, ".info"))
 			}
@@ -607,7 +597,7 @@ func rewriteVersionList(dir string) {
 	}
 	defer unlock()
 
-	infos, err := ioutil.ReadDir(dir)
+	infos, err := os.ReadDir(dir)
 	if err != nil {
 		return
 	}

libgo/go/cmd/go/internal/modfetch/cache_test.go

@@ -5,14 +5,13 @@
 package modfetch
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
 func TestWriteDiskCache(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "go-writeCache-test-")
+	tmpdir, err := os.MkdirTemp("", "go-writeCache-test-")
 	if err != nil {
 		t.Fatal(err)
 	}

libgo/go/cmd/go/internal/modfetch/codehost/codehost.go

@@ -11,7 +11,7 @@ import (
 	"crypto/sha256"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -79,9 +79,8 @@ type Repo interface {
 	ReadZip(rev, subdir string, maxSize int64) (zip io.ReadCloser, err error)
 
 	// RecentTag returns the most recent tag on rev or one of its predecessors
-	// with the given prefix and major version.
+	// with the given prefix. allowed may be used to filter out unwanted versions.
-	// An empty major string matches any major version.
+	RecentTag(rev, prefix string, allowed func(string) bool) (tag string, err error)
-	RecentTag(rev, prefix, major string) (tag string, err error)
 
 	// DescendsFrom reports whether rev or any of its ancestors has the given tag.
 	//
@@ -106,7 +105,7 @@ type FileRev struct {
 	Err  error  // error if any; os.IsNotExist(Err)==true if rev exists but file does not exist in that rev
 }
 
-// UnknownRevisionError is an error equivalent to os.ErrNotExist, but for a
+// UnknownRevisionError is an error equivalent to fs.ErrNotExist, but for a
 // revision rather than a file.
 type UnknownRevisionError struct {
 	Rev string
@@ -116,10 +115,10 @@ func (e *UnknownRevisionError) Error() string {
 	return "unknown revision " + e.Rev
 }
 func (UnknownRevisionError) Is(err error) bool {
-	return err == os.ErrNotExist
+	return err == fs.ErrNotExist
 }
 
-// ErrNoCommits is an error equivalent to os.ErrNotExist indicating that a given
+// ErrNoCommits is an error equivalent to fs.ErrNotExist indicating that a given
 // repository or module contains no commits.
 var ErrNoCommits error = noCommitsError{}
 
@@ -129,7 +128,7 @@ func (noCommitsError) Error() string {
 	return "no commits"
 }
 func (noCommitsError) Is(err error) bool {
-	return err == os.ErrNotExist
+	return err == fs.ErrNotExist
 }
 
 // AllHex reports whether the revision rev is entirely lower-case hexadecimal digits.
@@ -189,7 +188,7 @@ func WorkDir(typ, name string) (dir, lockfile string, err error) {
 	}
 	defer unlock()
 
-	data, err := ioutil.ReadFile(dir + ".info")
+	data, err := os.ReadFile(dir + ".info")
 	info, err2 := os.Stat(dir)
 	if err == nil && err2 == nil && info.IsDir() {
 		// Info file and directory both already exist: reuse.
@@ -211,7 +210,7 @@ func WorkDir(typ, name string) (dir, lockfile string, err error) {
 	if err := os.MkdirAll(dir, 0777); err != nil {
 		return "", "", err
 	}
-	if err := ioutil.WriteFile(dir+".info", []byte(key), 0666); err != nil {
+	if err := os.WriteFile(dir+".info", []byte(key), 0666); err != nil {
 		os.RemoveAll(dir)
 		return "", "", err
 	}
@@ -264,6 +263,9 @@ func RunWithStdin(dir string, stdin io.Reader, cmdline ...interface{}) ([]byte,
 	}
 
 	cmd := str.StringList(cmdline...)
+	if os.Getenv("TESTGOVCS") == "panic" {
+		panic(fmt.Sprintf("use of vcs: %v", cmd))
+	}
 	if cfg.BuildX {
 		text := new(strings.Builder)
 		if dir != "" {

libgo/go/cmd/go/internal/modfetch/codehost/git.go

@@ -9,7 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"net/url"
 	"os"
 	"os/exec"
@@ -34,13 +34,13 @@ func LocalGitRepo(remote string) (Repo, error) {
 }
 
 // A notExistError wraps another error to retain its original text
-// but makes it opaquely equivalent to os.ErrNotExist.
+// but makes it opaquely equivalent to fs.ErrNotExist.
 type notExistError struct {
 	err error
 }
 
 func (e notExistError) Error() string   { return e.err.Error() }
-func (notExistError) Is(err error) bool { return err == os.ErrNotExist }
+func (notExistError) Is(err error) bool { return err == fs.ErrNotExist }
 
 const gitWorkDirType = "git3"
 
@@ -188,7 +188,7 @@ func (r *gitRepo) loadRefs() {
 		// For HTTP and HTTPS, that's easy to detect: we'll try to fetch the URL
 		// ourselves and see what code it serves.
 		if u, err := url.Parse(r.remoteURL); err == nil && (u.Scheme == "http" || u.Scheme == "https") {
-			if _, err := web.GetBytes(u); errors.Is(err, os.ErrNotExist) {
+			if _, err := web.GetBytes(u); errors.Is(err, fs.ErrNotExist) {
 				gitErr = notExistError{gitErr}
 			}
 		}
@@ -505,7 +505,7 @@ func (r *gitRepo) ReadFile(rev, file string, maxSize int64) ([]byte, error) {
 	}
 	out, err := Run(r.dir, "git", "cat-file", "blob", info.Name+":"+file)
 	if err != nil {
-		return nil, os.ErrNotExist
+		return nil, fs.ErrNotExist
 	}
 	return out, nil
 }
@@ -629,9 +629,9 @@ func (r *gitRepo) readFileRevs(tags []string, file string, fileMap map[string]*F
 		case "tag", "commit":
 			switch fileType {
 			default:
-				f.Err = &os.PathError{Path: tag + ":" + file, Op: "read", Err: fmt.Errorf("unexpected non-blob type %q", fileType)}
+				f.Err = &fs.PathError{Path: tag + ":" + file, Op: "read", Err: fmt.Errorf("unexpected non-blob type %q", fileType)}
 			case "missing":
-				f.Err = &os.PathError{Path: tag + ":" + file, Op: "read", Err: os.ErrNotExist}
+				f.Err = &fs.PathError{Path: tag + ":" + file, Op: "read", Err: fs.ErrNotExist}
 			case "blob":
 				f.Data = fileData
 			}
@@ -644,7 +644,7 @@ func (r *gitRepo) readFileRevs(tags []string, file string, fileMap map[string]*F
 	return missing, nil
 }
 
-func (r *gitRepo) RecentTag(rev, prefix, major string) (tag string, err error) {
+func (r *gitRepo) RecentTag(rev, prefix string, allowed func(string) bool) (tag string, err error) {
 	info, err := r.Stat(rev)
 	if err != nil {
 		return "", err
@@ -680,7 +680,10 @@ func (r *gitRepo) RecentTag(rev, prefix, major string) (tag string, err error) {
 			// NOTE: Do not replace the call to semver.Compare with semver.Max.
 			// We want to return the actual tag, not a canonicalized version of it,
 			// and semver.Max currently canonicalizes (see golang.org/issue/32700).
-			if c := semver.Canonical(semtag); c != "" && strings.HasPrefix(semtag, c) && (major == "" || semver.Major(c) == major) && semver.Compare(semtag, highest) > 0 {
+			if c := semver.Canonical(semtag); c == "" || !strings.HasPrefix(semtag, c) || !allowed(semtag) {
+				continue
+			}
+			if semver.Compare(semtag, highest) > 0 {
 				highest = semtag
 			}
 		}
@@ -823,12 +826,12 @@ func (r *gitRepo) ReadZip(rev, subdir string, maxSize int64) (zip io.ReadCloser,
 	archive, err := Run(r.dir, "git", "-c", "core.autocrlf=input", "-c", "core.eol=lf", "archive", "--format=zip", "--prefix=prefix/", info.Name, args)
 	if err != nil {
 		if bytes.Contains(err.(*RunError).Stderr, []byte("did not match any files")) {
-			return nil, os.ErrNotExist
+			return nil, fs.ErrNotExist
 		}
 		return nil, err
 	}
 
-	return ioutil.NopCloser(bytes.NewReader(archive)), nil
+	return io.NopCloser(bytes.NewReader(archive)), nil
 }
 
 // ensureGitAttributes makes sure export-subst and export-ignore features are
@@ -859,7 +862,7 @@ func ensureGitAttributes(repoDir string) (err error) {
 		}
 	}()
 
-	b, err := ioutil.ReadAll(f)
+	b, err := io.ReadAll(f)
 	if err != nil {
 		return err
 	}

libgo/go/cmd/go/internal/modfetch/codehost/git_test.go

@@ -10,7 +10,8 @@ import (
 	"flag"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
+	"io"
+	"io/fs"
 	"log"
 	"os"
 	"os/exec"
@@ -52,7 +53,7 @@ func testMain(m *testing.M) int {
 		return 0
 	}
 
-	dir, err := ioutil.TempDir("", "gitrepo-test-")
+	dir, err := os.MkdirTemp("", "gitrepo-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -210,7 +211,7 @@ var readFileTests = []struct {
 		repo: gitrepo1,
 		rev:  "v2.3.4",
 		file: "another.txt",
-		err:  os.ErrNotExist.Error(),
+		err:  fs.ErrNotExist.Error(),
 	},
 }
 
@@ -432,7 +433,7 @@ func TestReadZip(t *testing.T) {
 			if tt.err != "" {
 				t.Fatalf("ReadZip: no error, wanted %v", tt.err)
 			}
-			zipdata, err := ioutil.ReadAll(rc)
+			zipdata, err := io.ReadAll(rc)
 			if err != nil {
 				t.Fatal(err)
 			}

libgo/go/cmd/go/internal/modfetch/codehost/shell.go

@@ -14,7 +14,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"strings"
@@ -115,7 +115,7 @@ func main() {
 				fmt.Fprintf(os.Stderr, "?%s\n", err)
 				continue
 			}
-			data, err := ioutil.ReadAll(rc)
+			data, err := io.ReadAll(rc)
 			rc.Close()
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "?%s\n", err)
@@ -123,7 +123,7 @@ func main() {
 			}
 
 			if f[3] != "-" {
-				if err := ioutil.WriteFile(f[3], data, 0666); err != nil {
+				if err := os.WriteFile(f[3], data, 0666); err != nil {
 					fmt.Fprintf(os.Stderr, "?%s\n", err)
 					continue
 				}