Hi,
Versions of the assembler using clang from XCode 12.5/12.5.1
have a bug which produces different code layout between debug and
non-debug input, leading to a compare fail for default configure
parameters.
This is a workaround fix to disable the optimisation that is
responsible for the bug.
tested on x86_64-darwin20, x86_64-darwin17, i686-darwin9 and on
x86_64-linux.
Pushed to master, thanks
Iain
Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>
PR target/100340 - Bootstrap fails with Clang 12.0.5 (XCode 12.5)
PR target/100340
gcc/ChangeLog:
* config.in: Regenerate.
* config/i386/darwin.h (EXTRA_ASM_OPTS): New
(ASM_SPEC): Pass options to disable branch shortening where
needed.
* configure: Regenerate.
* configure.ac: Detect versions of 'as' that support the
optimisation which has the bug.
---
gcc/config.in | 7 +++++++
gcc/config/i386/darwin.h | 10 +++++++++-
gcc/configure | 35 +++++++++++++++++++++++++++++++++++
gcc/configure.ac | 9 +++++++++
4 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/gcc/config.in b/gcc/config.in
index 7f5b01fad76..d8a810bbc91 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -616,6 +616,13 @@
#endif
+/* Define if your Mac OS X assembler supports -mllvm -x86-pad-for-align=false.
+ */
+#ifndef USED_FOR_TARGET
+#undef HAVE_AS_MLLVM_X86_PAD_FOR_ALIGN
+#endif
+
+
/* Define if your Mac OS X assembler supports the -mmacos-version-min option.
*/
#ifndef USED_FOR_TARGET
diff --git a/gcc/config/i386/darwin.h b/gcc/config/i386/darwin.h
index bac32197e83..73b06e2307d 100644
--- a/gcc/config/i386/darwin.h
+++ b/gcc/config/i386/darwin.h
@@ -125,10 +125,18 @@ along with GCC; see the file COPYING3. If not see
%{mfentry*:%eDarwin does not support -mfentry or associated options}" \
DARWIN_CC1_SPEC
+/* This is a workaround for a tool bug: see PR100340. */
+
+#ifdef HAVE_AS_MLLVM_X86_PAD_FOR_ALIGN
+#define EXTRA_ASM_OPTS " -mllvm -x86-pad-for-align=false"
+#else
+#define EXTRA_ASM_OPTS ""
+#endif
+
#undef ASM_SPEC
#define ASM_SPEC "-arch %(darwin_arch) \
" ASM_OPTIONS " -force_cpusubtype_ALL \
- %{static}" ASM_MMACOSX_VERSION_MIN_SPEC
+ %{static}" ASM_MMACOSX_VERSION_MIN_SPEC EXTRA_ASM_OPTS
#undef ENDFILE_SPEC
#define ENDFILE_SPEC \
diff --git a/gcc/configure b/gcc/configure
index 08c286764e0..a2d1003a0f5 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -27082,6 +27082,41 @@ $as_echo "$as_me: WARNING: LTO for $target requires
binutils >= 2.20.1, but vers
fi
;;
esac
+ case $target_os in
+ darwin2[0-9]* | darwin19*)
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for llvm
assembler x86-pad-for-align option" >&5
+$as_echo_n "checking assembler for llvm assembler x86-pad-for-align option...
" >&6; }
+if ${gcc_cv_as_mllvm_x86_pad_for_align+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ gcc_cv_as_mllvm_x86_pad_for_align=no
+ if test x$gcc_cv_as != x; then
+ $as_echo '.text' > conftest.s
+ if { ac_try='$gcc_cv_as $gcc_cv_as_flags -mllvm -x86-pad-for-align=false
-o conftest.o conftest.s >&5'
+ { { eval echo "\"\$as_me\":${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
+ gcc_cv_as_mllvm_x86_pad_for_align=yes
+ else
+ echo "configure: failed program was" >&5
+ cat conftest.s >&5
+ fi
+ rm -f conftest.o conftest.s
+ fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
$gcc_cv_as_mllvm_x86_pad_for_align" >&5
+$as_echo "$gcc_cv_as_mllvm_x86_pad_for_align" >&6; }
+if test $gcc_cv_as_mllvm_x86_pad_for_align = yes; then
+
+$as_echo "#define HAVE_AS_MLLVM_X86_PAD_FOR_ALIGN 1" >>confdefs.h
+
+fi
+
+ ;;
+ esac
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for
-xbrace_comment" >&5
$as_echo_n "checking assembler for -xbrace_comment... " >&6; }
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 653a1cc561d..ad8fa5a4604 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -4799,6 +4799,15 @@ foo: nop
fi
;;
esac
+ case $target_os in
+ darwin2[[0-9]]* | darwin19*)
+ gcc_GAS_CHECK_FEATURE([llvm assembler x86-pad-for-align option],
+ gcc_cv_as_mllvm_x86_pad_for_align,,
+ [-mllvm -x86-pad-for-align=false], [.text],,
+ [AC_DEFINE(HAVE_AS_MLLVM_X86_PAD_FOR_ALIGN, 1,
+ [Define if your Mac OS X assembler supports -mllvm
-x86-pad-for-align=false.])])
+ ;;
+ esac
gcc_GAS_CHECK_FEATURE([-xbrace_comment], gcc_cv_as_ix86_xbrace_comment,,
[-xbrace_comment=no], [.text],,
--
2.24.3 (Apple Git-128)
