[12/16] malloc: Use mtag_enabled instead of USE_MTAG
Commit Message
Use the runtime check where possible: it should not cause slow down in
the !USE_MTAG case since then mtag_enabled is constant false, but it
allows compiling the tagging logic so it's less likely to break or
diverge when developers only test the !USE_MTAG case.
---
malloc/hooks.c | 10 ++++------
malloc/malloc.c | 10 ++++------
2 files changed, 8 insertions(+), 12 deletions(-)
@@ -262,11 +262,10 @@ free_check (void *mem, const void *caller)
int err = errno;
-#ifdef USE_MTAG
/* Quickly check that the freed pointer matches the tag for the memory.
This gives a useful double-free detection. */
- *(volatile char *)mem;
-#endif
+ if (__glibc_unlikely (mtag_enabled))
+ *(volatile char *)mem;
__libc_lock_lock (main_arena.mutex);
p = mem2chunk_check (mem, NULL);
@@ -310,11 +309,10 @@ realloc_check (void *oldmem, size_t bytes, const void *caller)
return NULL;
}
-#ifdef USE_MTAG
/* Quickly check that the freed pointer matches the tag for the memory.
This gives a useful double-free detection. */
- *(volatile char *)oldmem;
-#endif
+ if (__glibc_unlikely (mtag_enabled))
+ *(volatile char *)oldmem;
__libc_lock_lock (main_arena.mutex);
const mchunkptr oldp = mem2chunk_check (oldmem, &magic_p);
@@ -3286,11 +3286,10 @@ __libc_free (void *mem)
if (mem == 0) /* free(0) has no effect */
return;
-#ifdef USE_MTAG
/* Quickly check that the freed pointer matches the tag for the memory.
This gives a useful double-free detection. */
- *(volatile char *)mem;
-#endif
+ if (__glibc_unlikely (mtag_enabled))
+ *(volatile char *)mem;
int err = errno;
@@ -3352,11 +3351,10 @@ __libc_realloc (void *oldmem, size_t bytes)
if (oldmem == 0)
return __libc_malloc (bytes);
-#ifdef USE_MTAG
/* Perform a quick check to ensure that the pointer's tag matches the
memory's tag. */
- *(volatile char*) oldmem;
-#endif
+ if (__glibc_unlikely (mtag_enabled))
+ *(volatile char*) oldmem;
/* chunk corresponding to oldmem */
const mchunkptr oldp = mem2chunk (oldmem);