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Speedup calloc size overflow check by preventing division if small values

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* malloc.c (GC_SQRT_SIZE_MAX): New macro.
* malloc.c (calloc): Add fast initial size overflow check to avoid
integer division for reasonably small values passed.
This commit is contained in:
Hans Boehm
2012-03-15 21:09:05 +04:00
committed by Ivan Maidanski
parent 6a93f8e5bc
commit 83231d0ab5
1 changed files with 4 additions and 1 deletions
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malloc.c
+4 -1
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@@ -381,9 +381,12 @@ void * malloc(size_t lb)
# define GC_SIZE_MAX (~(size_t)0)
#endif
#define GC_SQRT_SIZE_MAX ((1U << (WORDSZ / 2)) - 1)
void * calloc(size_t n, size_t lb)
{
if (lb && n > GC_SIZE_MAX / lb)
if ((lb | n) > GC_SQRT_SIZE_MAX /* fast initial test */
&& lb && n > GC_SIZE_MAX / lb)
return NULL;
# if defined(GC_LINUX_THREADS) /* && !defined(USE_PROC_FOR_LIBRARIES) */
/* libpthread allocated some memory that is only pointed to by */