From: Sören Tempel <soe...@soeren-tempel.net>
Since commit c163647ffbc9a20c8feb6e079dbecccfe016c82e -fsplit-stack
is only supported on glibc targets. However, this original commit
required some fixups. As part of the fixup, the changes to the
gnu-user-common.h and gnu.h were partially reverted in commit
60953a23d57b13a672f751bec0c6eefc059eb1ab thus causing TARGET_CAN_SPLIT_STACK
to be defined for non-glibc targets even though -fsplit-stack is
actually not supported and attempting to use it causes a runtime error.
This causes gcc internal code, such as ./gcc/go/gospec.c to not
correctly detect that -fsplit-stack is not supported and thus causes
gccgo to fail compilation on non-glibc targets.
This commit ensures that TARGET_CAN_SPLIT_STACK is only set if the
default libc is glibc. It is presently unclear to me if there is a
better way to detect glibc at pre-processor time.
The proposed changes have been tested on x86 and x86_64 Alpine Linux
(which uses musl libc) and fix compilation of gccgo for this target.
Signed-off-by: Sören Tempel <soe...@soeren-tempel.net>
gcc/ChangeLog:
* config/i386/gnu-user-common.h (defined): Only define
TARGET_CAN_SPLIT_STACK for glibc targets.
* config/i386/gnu.h (defined): Ditto.
---
Changes since v1: Use (DEFAULT_LIBC == LIBC_GLIBC) instead of
OPTION_GLIBC_P to detect use of glibc in a pre-processor context.
Is there a better way to detect use of glibc in the config header?
gcc/config/i386/gnu-user-common.h | 5 +++--
gcc/config/i386/gnu.h | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/gcc/config/i386/gnu-user-common.h
b/gcc/config/i386/gnu-user-common.h
index 00226f5a455..e126c3fa9fa 100644
--- a/gcc/config/i386/gnu-user-common.h
+++ b/gcc/config/i386/gnu-user-common.h
@@ -66,7 +66,8 @@ along with GCC; see the file COPYING3. If not see
#define STACK_CHECK_STATIC_BUILTIN 1
/* We only build the -fsplit-stack support in libgcc if the
- assembler has full support for the CFI directives. */
-#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE
+ assembler has full support for the CFI directives. Also
+ we only support -fsplit-stack on glibc targets. */
+#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE && (DEFAULT_LIBC == LIBC_GLIBC)
#define TARGET_CAN_SPLIT_STACK
#endif
diff --git a/gcc/config/i386/gnu.h b/gcc/config/i386/gnu.h
index 25fbc07f58c..17494333bb9 100644
--- a/gcc/config/i386/gnu.h
+++ b/gcc/config/i386/gnu.h
@@ -41,8 +41,9 @@ along with GCC. If not, see <http://www.gnu.org/licenses/>.
#define TARGET_THREAD_SSP_OFFSET 0x14
/* We only build the -fsplit-stack support in libgcc if the
- assembler has full support for the CFI directives. */
-#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE
+ assembler has full support for the CFI directives. Also
+ we only support -fsplit-stack on glibc targets. */
+#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE && (DEFAULT_LIBC == LIBC_GLIBC)
#define TARGET_CAN_SPLIT_STACK
#endif
/* We steal the last transactional memory word. */
