Campbell Barton
49babc7caa
Simplify logic for freeing a NULL pointer. While no null-pointer de-reference was performed, this wasn't as so obvious as the pointer was passed to MEM_lockfree_allocN_len before checking for NULL. NOTE: T99744 claimed the a NULL pointer free was a vulnerability, while I can't see evidence for this - exiting early makes it clearer the memory isn't accessed. *Details* - Add MEMHEAD_LEN macro, avoids redundant NULL check. - Use "UNLIKELY(..)" hint's for error cases (freeing NULL pointer and checking if `leak_detector_has_run`).