diff --git a/include/mimalloc-internal.h b/include/mimalloc-internal.h index 68239573..1df8b5de 100644 --- a/include/mimalloc-internal.h +++ b/include/mimalloc-internal.h @@ -247,11 +247,6 @@ static inline size_t _mi_wsize_from_size(size_t size) { return (size + sizeof(uintptr_t) - 1) / sizeof(uintptr_t); } -// Does malloc satisfy the alignment constraints already? -static inline bool mi_malloc_satisfies_alignment(size_t alignment, size_t size) { - return (alignment == sizeof(void*) || (alignment == MI_MAX_ALIGN_SIZE && size > (MI_MAX_ALIGN_SIZE/2))); -} - // Overflow detecting multiply #if __has_builtin(__builtin_umul_overflow) || (defined(__GNUC__) && (__GNUC__ >= 5)) #include // UINT_MAX, ULONG_MAX diff --git a/src/alloc-aligned.c b/src/alloc-aligned.c index 15062389..12706f7f 100644 --- a/src/alloc-aligned.c +++ b/src/alloc-aligned.c @@ -14,32 +14,14 @@ terms of the MIT license. A copy of the license can be found in the file // Aligned Allocation // ------------------------------------------------------ -static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t size, const size_t alignment, const size_t offset, const bool zero) mi_attr_noexcept { - // note: we don't require `size > offset`, we just guarantee that - // the address at offset is aligned regardless of the allocated size. - mi_assert(alignment > 0); - if (mi_unlikely(size > PTRDIFF_MAX)) return NULL; // we don't allocate more than PTRDIFF_MAX (see ) - if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) return NULL; // require power-of-two (see ) - if (mi_unlikely(alignment>MI_ALIGNED_MAX)) return NULL; // we cannot align at a boundary larger than this (or otherwise we cannot find segment headers) +// Fallback primitive aligned allocation -- split out for better codegen +static mi_decl_noinline void* mi_heap_malloc_zero_aligned_at_fallback(mi_heap_t* const heap, const size_t size, const size_t alignment, const size_t offset, const bool zero) mi_attr_noexcept +{ + mi_assert_internal(size <= PTRDIFF_MAX); + mi_assert_internal(alignment!=0 && _mi_is_power_of_two(alignment) && alignment <= MI_ALIGNED_MAX); + const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)` - - // try if there is a small block available with just the right alignment const size_t padsize = size + MI_PADDING_SIZE; - if (mi_likely(padsize <= MI_SMALL_SIZE_MAX)) { - mi_page_t* page = _mi_heap_get_free_small_page(heap,padsize); - const bool is_aligned = (((uintptr_t)page->free+offset) & align_mask)==0; - if (mi_likely(page->free != NULL && is_aligned)) - { - #if MI_STAT>1 - mi_heap_stat_increase( heap, malloc, size); - #endif - void* p = _mi_page_malloc(heap,page,padsize); // TODO: inline _mi_page_malloc - mi_assert_internal(p != NULL); - mi_assert_internal(((uintptr_t)p + offset) % alignment == 0); - if (zero) _mi_block_zero_init(page,p,size); - return p; - } - } // use regular allocation if it is guaranteed to fit the alignment constraints if (offset==0 && alignment<=padsize && padsize<=MI_MEDIUM_OBJ_SIZE_MAX && (padsize&align_mask)==0) { @@ -47,7 +29,7 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t mi_assert_internal(p == NULL || ((uintptr_t)p % alignment) == 0); return p; } - + // otherwise over-allocate void* p = _mi_heap_malloc_zero(heap, size + alignment - 1, zero); if (p == NULL) return NULL; @@ -56,21 +38,90 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t uintptr_t adjust = alignment - (((uintptr_t)p + offset) & align_mask); mi_assert_internal(adjust <= alignment); void* aligned_p = (adjust == alignment ? p : (void*)((uintptr_t)p + adjust)); - if (aligned_p != p) mi_page_set_has_aligned(_mi_ptr_page(p), true); + if (aligned_p != p) mi_page_set_has_aligned(_mi_ptr_page(p), true); mi_assert_internal(((uintptr_t)aligned_p + offset) % alignment == 0); - mi_assert_internal( p == _mi_page_ptr_unalign(_mi_ptr_segment(aligned_p),_mi_ptr_page(aligned_p),aligned_p) ); + mi_assert_internal(p == _mi_page_ptr_unalign(_mi_ptr_segment(aligned_p), _mi_ptr_page(aligned_p), aligned_p)); return aligned_p; } +// Primitive aligned allocation +static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t size, const size_t alignment, const size_t offset, const bool zero) mi_attr_noexcept +{ + // note: we don't require `size > offset`, we just guarantee that the address at offset is aligned regardless of the allocated size. + mi_assert(alignment > 0); + if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) { // require power-of-two (see ) + #if MI_DEBUG > 0 + _mi_error_message(EOVERFLOW, "aligned allocation requires the alignment to be a power-of-two (size %zu, alignment %zu)", size, alignment); + #endif + return NULL; + } + if (mi_unlikely(alignment > MI_ALIGNED_MAX)) { // we cannot align at a boundary larger than this (or otherwise we cannot find segment headers) + #if MI_DEBUG > 0 + _mi_error_message(EOVERFLOW, "aligned allocation has a maximum alignment of %zu (size %zu, alignment %zu)", MI_ALIGNED_MAX, size, alignment); + #endif + return NULL; + } + if (mi_unlikely(size > PTRDIFF_MAX)) { // we don't allocate more than PTRDIFF_MAX (see ) + #if MI_DEBUG > 0 + _mi_error_message(EOVERFLOW, "aligned allocation request is too large (size %zu, alignment %zu)", size, alignment); + #endif + return NULL; + } + const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)` + const size_t padsize = size + MI_PADDING_SIZE; // note: cannot overflow due to earlier size > PTRDIFF_MAX check + + // try first if there happens to be a small block available with just the right alignment + if (mi_likely(padsize <= MI_SMALL_SIZE_MAX)) { + mi_page_t* page = _mi_heap_get_free_small_page(heap, padsize); + const bool is_aligned = (((uintptr_t)page->free+offset) & align_mask)==0; + if (mi_likely(page->free != NULL && is_aligned)) + { + #if MI_STAT>1 + mi_heap_stat_increase(heap, malloc, size); + #endif + void* p = _mi_page_malloc(heap, page, padsize); // TODO: inline _mi_page_malloc + mi_assert_internal(p != NULL); + mi_assert_internal(((uintptr_t)p + offset) % alignment == 0); + if (zero) { _mi_block_zero_init(page, p, size); } + return p; + } + } + // fallback + return mi_heap_malloc_zero_aligned_at_fallback(heap, size, alignment, offset, zero); +} + + +// ------------------------------------------------------ +// Optimized mi_heap_malloc_aligned / mi_malloc_aligned +// ------------------------------------------------------ mi_decl_restrict void* mi_heap_malloc_aligned_at(mi_heap_t* heap, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { return mi_heap_malloc_zero_aligned_at(heap, size, alignment, offset, false); } mi_decl_restrict void* mi_heap_malloc_aligned(mi_heap_t* heap, size_t size, size_t alignment) mi_attr_noexcept { - return mi_heap_malloc_aligned_at(heap, size, alignment, 0); + #if !MI_PADDING + // without padding, any small sized allocation is naturally aligned (see also `_mi_segment_page_start`) + if (!_mi_is_power_of_two(alignment)) return NULL; + if (mi_likely(_mi_is_power_of_two(size) && size >= alignment && size <= MI_SMALL_SIZE_MAX)) + #else + // with padding, we can only guarantee this for fixed alignments + if (mi_likely((alignment == sizeof(void*) || (alignment == MI_MAX_ALIGN_SIZE && size > (MI_MAX_ALIGN_SIZE/2))) + && size <= MI_SMALL_SIZE_MAX)) + #endif + { + // fast path for common alignment and size + return mi_heap_malloc_small(heap, size); + } + else { + return mi_heap_malloc_aligned_at(heap, size, alignment, 0); + } } +// ------------------------------------------------------ +// Aligned Allocation +// ------------------------------------------------------ + mi_decl_restrict void* mi_heap_zalloc_aligned_at(mi_heap_t* heap, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { return mi_heap_malloc_zero_aligned_at(heap, size, alignment, offset, true); } @@ -114,6 +165,10 @@ mi_decl_restrict void* mi_calloc_aligned(size_t count, size_t size, size_t align } +// ------------------------------------------------------ +// Aligned re-allocation +// ------------------------------------------------------ + static void* mi_heap_realloc_zero_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset, bool zero) mi_attr_noexcept { mi_assert(alignment > 0); if (alignment <= sizeof(uintptr_t)) return _mi_heap_realloc_zero(heap,p,newsize,zero); diff --git a/src/alloc-posix.c b/src/alloc-posix.c index 2eaede07..efe62817 100644 --- a/src/alloc-posix.c +++ b/src/alloc-posix.c @@ -56,9 +56,9 @@ int mi_posix_memalign(void** p, size_t alignment, size_t size) mi_attr_noexcept // Note: The spec dictates we should not modify `*p` on an error. (issue#27) // if (p == NULL) return EINVAL; - if (alignment % sizeof(void*) != 0) return EINVAL; // natural alignment - if (!_mi_is_power_of_two(alignment)) return EINVAL; // not a power of 2 - void* q = (mi_malloc_satisfies_alignment(alignment, size) ? mi_malloc(size) : mi_malloc_aligned(size, alignment)); + if (alignment % sizeof(void*) != 0) return EINVAL; // natural alignment + if (alignment==0 || !_mi_is_power_of_two(alignment)) return EINVAL; // not a power of 2 + void* q = mi_malloc_aligned(size, alignment); if (q==NULL && size != 0) return ENOMEM; mi_assert_internal(((uintptr_t)q % alignment) == 0); *p = q; @@ -66,7 +66,7 @@ int mi_posix_memalign(void** p, size_t alignment, size_t size) mi_attr_noexcept } mi_decl_restrict void* mi_memalign(size_t alignment, size_t size) mi_attr_noexcept { - void* p = (mi_malloc_satisfies_alignment(alignment,size) ? mi_malloc(size) : mi_malloc_aligned(size, alignment)); + void* p = mi_malloc_aligned(size, alignment); mi_assert_internal(((uintptr_t)p % alignment) == 0); return p; } @@ -83,9 +83,14 @@ mi_decl_restrict void* mi_pvalloc(size_t size) mi_attr_noexcept { } mi_decl_restrict void* mi_aligned_alloc(size_t alignment, size_t size) mi_attr_noexcept { - if (alignment==0 || !_mi_is_power_of_two(alignment)) return NULL; - if ((size&(alignment-1)) != 0) return NULL; // C11 requires integral multiple, see - void* p = (mi_malloc_satisfies_alignment(alignment, size) ? mi_malloc(size) : mi_malloc_aligned(size, alignment)); + if (mi_unlikely((size&(alignment-1)) != 0)) { // C11 requires alignment>0 && integral multiple, see + #if MI_DEBUG > 0 + _mi_error_message(EOVERFLOW, "(mi_)aligned_alloc requires the size to be an integral multiple of the alignment (size %zu, alignment %zu)", size, alignment); + #endif + return NULL; + } + // C11 also requires alignment to be a power-of-two which is checked in mi_malloc_aligned + void* p = mi_malloc_aligned(size, alignment); mi_assert_internal(((uintptr_t)p % alignment) == 0); return p; } diff --git a/test/main-override-static.c b/test/main-override-static.c index 221db7e8..071e4248 100644 --- a/test/main-override-static.c +++ b/test/main-override-static.c @@ -42,7 +42,7 @@ int main() { free(p1); free(p2); free(s); - + /* now test if override worked by allocating/freeing across the api's*/ //p1 = mi_malloc(32); //free(p1); diff --git a/test/test-api.c b/test/test-api.c index 8ddbf7cf..1f810d53 100644 --- a/test/test-api.c +++ b/test/test-api.c @@ -158,6 +158,16 @@ int main(void) { CHECK_BODY("malloc-aligned5", { void* p = mi_malloc_aligned(4097,4096); size_t usable = mi_usable_size(p); result = usable >= 4097 && usable < 10000; mi_free(p); }); + CHECK_BODY("malloc-aligned6", { + void* p; + bool ok = true; + for (int i = 1; i < 8 && ok; i++) { + size_t align = 1UL << i; + p = mi_malloc_aligned(2*align, align); + ok = (p != NULL && (uintptr_t)(p) % align == 0); mi_free(p); + } + result = ok; + }); CHECK_BODY("malloc-aligned-at1", { void* p = mi_malloc_aligned_at(48,32,0); result = (p != NULL && ((uintptr_t)(p) + 0) % 32 == 0); mi_free(p); }); @@ -172,8 +182,8 @@ int main(void) { ok = (p != NULL && (uintptr_t)(p) % 16 == 0); mi_free(p); } result = ok; - }); - + }); + // --------------------------------------------------- // Heaps // ---------------------------------------------------