vppinfra: fix memcpy undefined behaviour
Calling mem{cpy,move} with NULL pointers results in undefined behaviour.
This in turns is exploited by GCC. For example, the sequence:
memcpy (dst, src, n);
if (!src)
return;
src[0] = 0xcafe;
will be optimized as
memcpy (dst, src, n);
src[0] = 0xcafe;
IOW the test for NULL is gone.
vec_*() functions sometime call memcpy with NULL pointers and 0 length,
triggering this optimization. For example, the sequence:
vec_append(v1, v2);
len = vec_len(v2);
will crash if v2 is NULL, because the test for NULL pointer in vec_len()
has been optimized out.
This commit fixes occurrences of such undefined behaviour, and also
introduces a memcpy wrapper to catch those in debug mode.
Type: fix
Change-Id: I175e2dd726a883f97cf7de3b15f66d4b237ddefd
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/vppinfra/memcpy_avx512.h b/src/vppinfra/memcpy_avx512.h
index 1444c27..98dac75 100644
--- a/src/vppinfra/memcpy_avx512.h
+++ b/src/vppinfra/memcpy_avx512.h
@@ -144,7 +144,7 @@
}
static inline void *
-clib_memcpy_fast (void *dst, const void *src, size_t n)
+clib_memcpy_fast_avx512 (void *dst, const void *src, size_t n)
{
uword dstu = (uword) dst;
uword srcu = (uword) src;