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>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/vppinfra/memcpy_avx2.h b/src/vppinfra/memcpy_avx2.h
index f3f0d3f1943..f7a36f0e5cb 100644
--- a/src/vppinfra/memcpy_avx2.h
+++ b/src/vppinfra/memcpy_avx2.h
@@ -114,7 +114,7 @@ clib_mov128blocks (u8 * dst, const u8 * src, size_t n)
 }
 
 static inline void *
-clib_memcpy_fast (void *dst, const void *src, size_t n)
+clib_memcpy_fast_avx2 (void *dst, const void *src, size_t n)
 {
   uword dstu = (uword) dst;
   uword srcu = (uword) src;