Since "6fbec038f7a Use SHF_GNU_RETAIN to preserve symbol definitions",
GCC could create sections with the 'R' flag, which GAS would map to
SHF_GNU_RETAIN.
SHF_GNU_RETAIN support was not available in gold until Binutils commit
ff4bc37d77, on 2020-12-14. Until the support was added, invalid binaries
could be created if some special sections, such as .init_array, had
SHF_GNU_RETAIN set.
HAVE_GAS_SHF_GNU_RETAIN is now disabled if a version of gold without
SHF_GNU_RETAIN support is detected.
I tested that HAVE_GAS_SHF_GNU_RETAIN was enabled/disabled as
appropriate in a number of configurations, using both in-tree and
out-of-tree Binutils:
- Before the Binutils gold patch:
* gold disabled == SHF_GNU_RETAIN enabled
* gold enabled == SHF_GNU_RETAIN disabled
- After the Binutils gold patch:
* gold disabled == SHF_GNU_RETAIN enabled
* gold enabled == SHF_GNU_RETAIN enabled
Successfully bootstrapped for x86_64-pc-linux-gnu.
Ok to apply?
>From af3000bbacc6d8ca57581c11790032b73ea944ac Mon Sep 17 00:00:00 2001
From: Jozef Lawrynowicz
Date: Wed, 16 Dec 2020 18:33:54 +0000
Subject: [PATCH] configure: Extend SHF_GNU_RETAIN conftest to check for
unsupported gold
Since "6fbec038f7a Use SHF_GNU_RETAIN to preserve symbol definitions",
GCC could create sections with the 'R' flag, which GAS would map to
SHF_GNU_RETAIN.
SHF_GNU_RETAIN support was not available in gold until Binutils commit
ff4bc37d77, on 2020-12-14. Until the support was added, invalid binaries
could be created if some special sections, such as .init_array, had
SHF_GNU_RETAIN set.
HAVE_GAS_SHF_GNU_RETAIN is now disabled if a version of gold without
SHF_GNU_RETAIN support is detected.
gcc/ChangeLog:
PR target/98210
* configure: Regenerate.
* configure.ac (gcc_cv_as_shf_gnu_retain): Disable
HAVE_GAS_SHF_GNU_RETAIN for gold versions that do not support it.
---
gcc/configure| 60 -
gcc/configure.ac | 64 +---
2 files changed, 120 insertions(+), 4 deletions(-)
diff --git a/gcc/configure b/gcc/configure
index 9a27e459f14..544ec92463e 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -24442,7 +24442,63 @@ case "${target}" in
gcc_cv_as_shf_gnu_retain=no
;;
*)
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for section
'R' flag" >&5
+# gold did not support SHF_GNU_RETAIN until 2.35.50.20201215.
+# Support for SHF_GNU_RETAIN in GCC was only added on 2020-12-01, so rather
+# than only disabling the GCC functionality if gold is the default, disable
+# it if a gold without the support has been built at all.
+
+ld_gold=`which ${gcc_cv_ld}.gold`
+check_gold_ver=no
+if test x$ld_is_gold = xyes; then
+ # Always check_gold_ver when gold is the default linker.
+ check_gold_ver=yes
+ gold_date=$ld_date
+elif test -f ../gold/ld-new$build_exeext; then
+ # Always check_gold_ver when gold has been built in-tree.
+ check_gold_ver=yes
+ gold_ver=`../gold/ld-new$build_exeext --version 2>/dev/null | sed 1q`
+ gold_date=`echo $gold_ver | sed -n
's,^.*\([2-9][0-9][0-9][0-9]\)\(-*\)\([01][0-9]\)\2\([0-3][0-9]\).*$,\1\3\4,p'`
+elif test -n "$ld_gold"; then
+ gold_ver=`${gcc_cv_ld}.gold --version 2>/dev/null | sed 1q`
+ gold_vers=`echo $gold_ver | sed -n \
+ -e 's,^[^)]*[ ]\([0-9][0-9]*\.[0-9][0-9]*[^)]*\)) .*$,\1,p'`
+ gold_date=`echo $gold_ver | sed -n
's,^.*\([2-9][0-9][0-9][0-9]\)\(-*\)\([01][0-9]\)\2\([0-3][0-9]\).*$,\1\3\4,p'`
+ gold_vers_major=`expr "$gold_vers" : '\([0-9]*\)'`
+ gold_vers_minor=`expr "$gold_vers" : '[0-9]*\.\([0-9]*\)'`
+ gold_vers_patch=`expr "$gold_vers" : '[0-9]*\.[0-9]*\.\([0-9]*\)'`
+
+ # If gold exists but is not the default linker, we assume that it is
+ # still intended to be used if the version matches the default ld.
+ if test 0"$gold_vers_major" -eq 0"$ld_vers_major" \
+ && test 0"$gold_vers_minor" -eq 0"$ld_vers_minor" \
+ && test 0"$gold_vers_patch" -eq 0"$ld_vers_patch" \
+ && test 0"$gold_date" -eq 0"$ld_date"; then
+ check_gold_ver=yes
+ fi
+fi
+
+# To test for the period of time when the SHF_GNU_RETAIN flag is supported
+# in ld, but not in gold, check the date in the version string. If there
+# is no date, then we let gcc_GAS_CHECK_FEATURE make the correct
+# choice.
+if test $check_gold_ver = yes && test -n "$gold_date" \
+ && test 0"$gold_date" -lt 20201215; then
+ gcc_cv_as_shf_gnu_retain=no
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking gold support for
SHF_GNU_RETAIN" >&5
+$as_echo_n "checking go
