On targets where libc implements stack protector functions (GNU libc,
FreeBSD libc), and where gcc (as an optimisation) generates calls to
a locally defined __stack_chk_fail_local instead of directly calling
the global function __stack_chk_fail (e.g. -fpic code on i386), one
must explicitly specify -lssp_nonshared or "-lc -lc_nonshared" on the
command line to statically link in __stack_chk_fail_local.
It would be more convenient if the compiler kept the details of this
target specific optimisation hidden by passing -lssp_nonshared to the
linker internally.
Here's a simple test case that shows the problem on i386-freebsd, but
works just fine on e.g. x86_64 targets:
% cat test.c
int
main( void ) {
return( 0 );
}
% gcc46 -o test test.c -fstack-protector-all -fPIE
/var/tmp//ccjYQxKu.o: In function `main':
test.c:(.text+0x37): undefined reference to `__stack_chk_fail_local'
/usr/local/bin/ld: test: hidden symbol `__stack_chk_fail_local' isn't defined
/usr/local/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status
I don't have commit access, so please commit when approved.
2011-01-10 Tijl Coosemans <t...@coosemans.org>
* gcc.c [TARGET_LIBC_PROVIDES_SSP] (LINK_SSP_SPEC): Add -lssp_nonshared.
--- gcc/gcc.c.orig
+++ gcc/gcc.c
@@ -602,7 +602,7 @@ proper position among the other output f
#ifndef LINK_SSP_SPEC
#ifdef TARGET_LIBC_PROVIDES_SSP
-#define LINK_SSP_SPEC "%{fstack-protector:}"
+#define LINK_SSP_SPEC
"%{fstack-protector|fstack-protector-all:-lssp_nonshared}"
#else
#define LINK_SSP_SPEC "%{fstack-protector|fstack-protector-all:-lssp_nonshared
-lssp}"
#endif
