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Replace check_mul_overflow_size_t with __builtin_mul_overflow

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Checked on x86_64-linux-gnu and i686-linux-gnu.

	* malloc/alloc_buffer_alloc_array.c (__libc_alloc_buffer_alloc_array):
	Use __builtin_mul_overflow in place of check_mul_overflow_size_t.
	* malloc/dynarray_emplace_enlarge.c (__libc_dynarray_emplace_enlarge):
	Likewise.
	* malloc/dynarray_resize.c (__libc_dynarray_resize): Likewise.
	* malloc/reallocarray.c (__libc_reallocarray): Likewise.
	* malloc/malloc-internal.h (check_mul_overflow_size_t): Remove
	function.
	* support/blob_repeat.c (check_mul_overflow_size_t,
	(minimum_stride_size, support_blob_repeat_allocate): Likewise.
This commit is contained in:
Adhemerval Zanella
2018-12-21 09:49:37 -02:00
parent 09104e5ba4
commit 0253580a75
7 changed files with 21 additions and 53 deletions
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26
support/blob_repeat.c
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@ -34,26 +34,6 @@
optimization because mappings carry a lot of overhead. */
static const size_t maximum_small_size = 4 * 1024 * 1024;
/* Set *RESULT to LEFT * RIGHT. Return true if the multiplication
overflowed. See <malloc/malloc-internal.h>. */
static inline bool
check_mul_overflow_size_t (size_t left, size_t right, size_t *result)
{
#if __GNUC__ >= 5
return __builtin_mul_overflow (left, right, result);
#else
/* size_t is unsigned so the behavior on overflow is defined. */
*result = left * right;
size_t half_size_t = ((size_t) 1) << (8 * sizeof (size_t) / 2);
if (__glibc_unlikely ((left | right) >= half_size_t))
{
if (__glibc_unlikely (right != 0 && *result / right != left))
return true;
}
return false;
#endif
}
/* Internal helper for fill. */
static void
fill0 (char *target, const char *element, size_t element_size,
@ -138,8 +118,8 @@ minimum_stride_size (size_t page_size, size_t element_size)
common multiple, it appears only once. Therefore, shift one
factor. */
size_t multiple;
if (check_mul_overflow_size_t (page_size >> common_zeros, element_size,
&multiple))
if (__builtin_mul_overflow (page_size >> common_zeros, element_size,
&multiple))
return 0;
return multiple;
}
@ -275,7 +255,7 @@ support_blob_repeat_allocate (const void *element, size_t element_size,
size_t count)
{
size_t total_size;
if (check_mul_overflow_size_t (element_size, count, &total_size))
if (__builtin_mul_overflow (element_size, count, &total_size))
{
errno = EOVERFLOW;
return (struct support_blob_repeat) { 0 };