Hello!
Attached patch fixes several go testcase failures on CentOS 5.9 with
ancient (GNU ld version 2.17.50.0.6-20.el5_8.3 20061020) binutils.
These do not have CFI personality directive, so -fsplit-stack should
not be used there.
The compiler detects this situation through
TARGET_SUPPORTS_SPLIT_STACK target hook, but the go driver
nevertheless emits -fsplit-stack option, depending solely on the
definition of TARGET_CAN_SPLIT_STACK. Forcing -fsplit-stack from the
driver triggers the error from the above target hook.
To fix this situation, attached patch declares TARGET_CAN_SPLIT_STACK
only in case HAVE_GAS_CFI_PERSONALITY is set (please note that it
should be *set*, not only *defined*).
2013-02-08 Uros Bizjak <ubiz...@gmail.com>
* config/i386/gnu-user.h (TARGET_CAN_SPLIT_STACK): Define only
when HAVE_GAS_CFI_PERSONALITY_DIRECTIVE is set.
* config/i386/gnu-user64.h (TARGET_CAN_SPLIT_STACK): Ditto.
Patch was bootstrapped and regression tested on x86_64-pc-linux-gnu
{,-m32} on Fedora17 (GNU ld version 2.22.52.0.1-10.fc17 20120131) and
CentOS 5.9 (GNU ld version 2.17.50.0.6-20.el5_8.3 20061020), where it
fixes many go testsuite failures.
Ian, although this is purely x86 patch, can you please approve it from
go perspective (go is the only user of TARGET_CAN_SPLIT_STACK)?
Uros.
Index: config/i386/gnu-user64.h
===================================================================
--- config/i386/gnu-user64.h (revision 195875)
+++ config/i386/gnu-user64.h (working copy)
@@ -85,8 +85,10 @@
#define TARGET_THREAD_SSP_OFFSET \
(TARGET_64BIT ? (TARGET_X32 ? 0x18 : 0x28) : 0x14)
+#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE
+#define TARGET_CAN_SPLIT_STACK
+#endif
/* We steal the last transactional memory word. */
-#define TARGET_CAN_SPLIT_STACK
#define TARGET_THREAD_SPLIT_STACK_OFFSET \
(TARGET_64BIT ? (TARGET_X32 ? 0x40 : 0x70) : 0x30)
#endif
Index: config/i386/gnu-user.h
===================================================================
--- config/i386/gnu-user.h (revision 195875)
+++ config/i386/gnu-user.h (working copy)
@@ -154,7 +154,9 @@
/* i386 glibc provides __stack_chk_guard in %gs:0x14. */
#define TARGET_THREAD_SSP_OFFSET 0x14
+#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE
+#define TARGET_CAN_SPLIT_STACK
+#endif
/* We steal the last transactional memory word. */
-#define TARGET_CAN_SPLIT_STACK
#define TARGET_THREAD_SPLIT_STACK_OFFSET 0x30
#endif
