fortification

[Iain Hibbert <plunky%ogmig.net@localhost>]

Hello

while I was looking at the ssp/fortification code, I noticed something..
the following code example

#include <string.h>

int a, b;

void foo(void)
{
	memcpy(&a, &b, sizeof(a));
}

when preprocessed with fortification enabled

% gcc -fstack-protector -O2 -D_FORTIFY_SOURCE=2 -E -o test.i test.c

outputs basically the following code (I've added spaces and cut out the 
unrelated parts)

static __inline void * __memcpy_ichk(void * __restrict__, const void * __restrict__, size_t);

static __inline __attribute__((__always_inline__)) void * __memcpy_ichk(void * __restrict__ dst, const void * __restrict__ src, size_t len)
{
	return __builtin___memcpy_chk(dst, src, len, __builtin_object_size(dst, 0));
}

int a, b;

void foo(void)
{
	(
		(__builtin_object_size(&a, 0) != (size_t)-1)
	?
		__builtin___memcpy_chk(&a, &b, sizeof(a), __builtin_object_size(&a, 0))
	:
		__memcpy_ichk(&a, &b, sizeof(a))
	);
}


which seems like it is wrong, since both branches end up with the same 
code..  should the inline __memcpy_ichk() function actually call 
__memcpy_chk() from libc?  I'm not sure of the rationale here..

regards,
iain