[glibc/azanella/clang] Use check tests with trampolines iff compiler supports it

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b2e3db301a3b18c37cf422812dda46cf532b35bb

commit b2e3db301a3b18c37cf422812dda46cf532b35bb
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Fri Mar 25 08:58:03 2022 -0300

    Use check tests with trampolines iff compiler supports it

Diff:
---
 configure     | 32 ++++++++++++++++++++++++++++++++
 configure.ac  | 20 ++++++++++++++++++++
 elf/Makefile  | 10 +++++-----
 nptl/Makefile |  6 ++++--
 4 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/configure b/configure
index c8ec3471d4..709a572377 100755
--- a/configure
+++ b/configure
@@ -6595,6 +6595,38 @@ if test $libc_cv_cc_loop_to_function = yes; then
 fi
 
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if $CC has support for trampolines" >&5
+$as_echo_n "checking if $CC has support for trampolines... " >&6; }
+if ${libc_cv_cc_trampoline+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.c <<EOF
+void bar (void (*callback) (void));
+int foo (void)
+{
+  int var = 0;
+  void callback (void) { var = 1; }
+  bar (callback);
+  return var;
+}
+EOF
+libc_cv_cc_trampoline=no
+if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -Werror -c conftest.c'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then
+  libc_cv_cc_trampoline=yes
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_trampoline" >&5
+$as_echo "$libc_cv_cc_trampoline" >&6; }
+config_vars="$config_vars
+have-cc-trampoline = $libc_cv_cc_trampoline"
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libgd" >&5
 $as_echo_n "checking for libgd... " >&6; }
 if test "$with_gd" != "no"; then
diff --git a/configure.ac b/configure.ac
index 996d674399..8c9c70fca3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1589,6 +1589,26 @@ if test $libc_cv_cc_loop_to_function = yes; then
 fi
 AC_SUBST(libc_cv_cc_loop_to_function)
 
+AC_CACHE_CHECK(if $CC has support for trampolines, libc_cv_cc_trampoline, [dnl
+cat > conftest.c <<EOF
+void bar (void (*callback) (void));
+int foo (void)
+{
+  int var = 0;
+  void callback (void) { var = 1; }
+  bar (callback);
+  return var;
+}
+EOF
+libc_cv_cc_trampoline=no
+if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -Werror -c conftest.c])
+then
+  libc_cv_cc_trampoline=yes
+fi
+rm -f conftest*])
+LIBC_CONFIG_VAR([have-cc-trampoline],
+		[$libc_cv_cc_trampoline])
+
 dnl Check whether we have the gd library available.
 AC_MSG_CHECKING(for libgd)
 if test "$with_gd" != "no"; then
diff --git a/elf/Makefile b/elf/Makefile
index fc9860edee..0aafe43056 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -520,7 +520,7 @@ endif
 selinux-enabled := $(shell cat /selinux/enforce 2> /dev/null)
 
 ifneq ($(selinux-enabled),1)
-tests-execstack-yes = \
+tests-execstack-yesyes = \
   tst-execstack \
   tst-execstack-needed \
   tst-execstack-prog \
@@ -621,7 +621,7 @@ $(objpfx)tst-valgrind-smoke.out: tst-valgrind-smoke.sh $(objpfx)ld.so $(objpfx)v
 	$(SHELL) $< $(objpfx)ld.so  $(rtlddir)/$(rtld-installed-name) '$(test-wrapper-env)' \
 		'$(run-program-env)' '$(rpath-link)' $(objpfx)valgrind-test > $@; $(evaluate-test)
 
-tests += $(tests-execstack-$(have-z-execstack))
+tests += $(tests-execstack-$(have-z-execstack)$(have-cc-trampoline))
 ifeq ($(run-built-tests),yes)
 tests-special += \
   $(objpfx)noload-mem.out \
@@ -962,7 +962,7 @@ modules-names-cxx = \
 
 modules-names += \
   $(if $(CXX),$(modules-names-cxx)) \
-  $(modules-execstack-$(have-z-execstack)) \
+  $(modules-execstack-$(have-z-execstack)$(have-cc-trampoline)) \
   $(tlsmod17a-modules) \
   $(tlsmod18a-modules) \
   $(tst-tls-many-dynamic-modules) \
@@ -1026,7 +1026,7 @@ tests-pie += vismain
 CFLAGS-vismain.c += $(PIE-ccflag)
 endif
 endif
-modules-execstack-yes = tst-execstack-mod
+modules-execstack-yesyes = tst-execstack-mod
 extra-test-objs += $(addsuffix .os,$(strip $(modules-names)))
 
 # filtmod1.so, tst-big-note-lib.so, tst-ro-dynamic-mod.so have special
@@ -1803,7 +1803,7 @@ $(objpfx)unload8.out: $(objpfx)unload8mod1.so $(objpfx)unload8mod1x.so
 
 $(objpfx)tst-tls9-static.out: $(objpfx)tst-tlsmod5.so $(objpfx)tst-tlsmod6.so
 
-ifeq ($(have-z-execstack),yes)
+ifeq ($(have-z-execstack)$(have-cc-trampoline),yesyes)
 $(objpfx)tst-execstack.out: $(objpfx)tst-execstack-mod.so
 CPPFLAGS-tst-execstack.c += -DUSE_PTHREADS=0
 LDFLAGS-tst-execstack = -Wl,-z,noexecstack
diff --git a/nptl/Makefile b/nptl/Makefile
index b585663974..dbbe0ae737 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -387,7 +387,7 @@ tests += tst-cancelx7 tst-cancelx17
 ifeq ($(build-shared),yes)
 tests += tst-compat-forwarder tst-audit-threads
 tests-internal += tst-tls3 tst-tls3-malloc tst-tls5 tst-stackguard1
-ifeq ($(have-z-execstack),yes)
+ifeq ($(have-z-execstack)$(have-cc-trampoline),yesyes)
 tests += tst-execstack
 endif
 endif
@@ -395,9 +395,11 @@ endif
 modules-names = tst-tls3mod \
 		tst-tls5mod tst-tls5moda tst-tls5modb tst-tls5modc \
 		tst-tls5modd tst-tls5mode tst-tls5modf tst-stack4mod \
-		tst-execstack-mod \
 		tst-compat-forwarder-mod tst-audit-threads-mod1 \
 		tst-audit-threads-mod2
+ifeq ($(have-z-execstack)$(have-cc-trampoline),yesyes)
+modules-names += tst-execstack-mod
+endif
 extra-test-objs += $(addsuffix .os,$(strip $(modules-names))) \
 		   tst-cleanup4aux.o tst-cleanupx4aux.o
 test-extras += tst-cleanup4aux tst-cleanupx4aux