| /* ---------------------------------------------------------------------------- |
| Copyright (c) 2018-2021, Microsoft Research, Daan Leijen |
| This is free software; you can redistribute it and/or modify it under the |
| terms of the MIT license. A copy of the license can be found in the file |
| "LICENSE" at the root of this distribution. |
| -----------------------------------------------------------------------------*/ |
| |
| #include "mimalloc.h" |
| #include "mimalloc-internal.h" |
| |
| #include <string.h> // memset |
| |
| // ------------------------------------------------------ |
| // Aligned Allocation |
| // ------------------------------------------------------ |
| |
| // 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)); |
| |
| const uintptr_t align_mask = alignment - 1; // for any x, `(x & align_mask) == (x % alignment)` |
| const size_t padsize = size + MI_PADDING_SIZE; |
| |
| // use regular allocation if it is guaranteed to fit the alignment constraints |
| if (offset==0 && alignment<=padsize && padsize<=MI_MAX_ALIGN_GUARANTEE && (padsize&align_mask)==0) { |
| void* p = _mi_heap_malloc_zero(heap, size, zero); |
| mi_assert_internal(p == NULL || ((uintptr_t)p % alignment) == 0); |
| return p; |
| } |
| |
| void* p; |
| size_t oversize; |
| if mi_unlikely(alignment > MI_ALIGNMENT_MAX) { |
| // use OS allocation for very large alignment and allocate inside a huge page (dedicated segment with 1 page) |
| // This can support alignments >= MI_SEGMENT_SIZE by ensuring the object can be aligned at a point in the |
| // first (and single) page such that the segment info is `MI_SEGMENT_SIZE` bytes before it (so it can be found by aligning the pointer down) |
| if mi_unlikely(offset != 0) { |
| // todo: cannot support offset alignment for very large alignments yet |
| #if MI_DEBUG > 0 |
| _mi_error_message(EOVERFLOW, "aligned allocation with a very large alignment cannot be used with an alignment offset (size %zu, alignment %zu, offset %zu)\n", size, alignment, offset); |
| #endif |
| return NULL; |
| } |
| oversize = (size <= MI_SMALL_SIZE_MAX ? MI_SMALL_SIZE_MAX + 1 /* ensure we use generic malloc path */ : size); |
| p = _mi_heap_malloc_zero_ex(heap, oversize, false, alignment); // the page block size should be large enough to align in the single huge page block |
| // zero afterwards as only the area from the aligned_p may be committed! |
| if (p == NULL) return NULL; |
| } |
| else { |
| // otherwise over-allocate |
| oversize = size + alignment - 1; |
| p = _mi_heap_malloc_zero(heap, oversize, zero); |
| if (p == NULL) return NULL; |
| } |
| |
| // .. and align within the allocation |
| const uintptr_t poffset = ((uintptr_t)p + offset) & align_mask; |
| const uintptr_t adjust = (poffset == 0 ? 0 : alignment - poffset); |
| mi_assert_internal(adjust < alignment); |
| void* aligned_p = (void*)((uintptr_t)p + adjust); |
| if (aligned_p != p) { |
| mi_page_set_has_aligned(_mi_ptr_page(p), true); |
| } |
| |
| mi_assert_internal(mi_page_usable_block_size(_mi_ptr_page(p)) >= adjust + size); |
| mi_assert_internal(p == _mi_page_ptr_unalign(_mi_ptr_segment(aligned_p), _mi_ptr_page(aligned_p), aligned_p)); |
| mi_assert_internal(((uintptr_t)aligned_p + offset) % alignment == 0); |
| mi_assert_internal(mi_page_usable_block_size(_mi_ptr_page(p)) >= adjust + size); |
| |
| // now zero the block if needed |
| if (zero && alignment > MI_ALIGNMENT_MAX) { |
| const ptrdiff_t diff = (uint8_t*)aligned_p - (uint8_t*)p; |
| const ptrdiff_t zsize = mi_page_usable_block_size(_mi_ptr_page(p)) - diff - MI_PADDING_SIZE; |
| if (zsize > 0) { _mi_memzero(aligned_p, zsize); } |
| } |
| |
| #if MI_TRACK_ENABLED |
| if (p != aligned_p) { |
| mi_track_free_size(p, oversize); |
| mi_track_malloc(aligned_p, size, zero); |
| } |
| else { |
| mi_track_resize(aligned_p, oversize, size); |
| } |
| #endif |
| 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 <https://en.cppreference.com/w/c/memory/aligned_alloc>) |
| #if MI_DEBUG > 0 |
| _mi_error_message(EOVERFLOW, "aligned allocation requires the alignment to be a power-of-two (size %zu, alignment %zu)\n", size, alignment); |
| #endif |
| return NULL; |
| } |
| /* |
| if mi_unlikely(alignment > MI_ALIGNMENT_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)\n", MI_ALIGNMENT_MAX, size, alignment); |
| #endif |
| return NULL; |
| } |
| */ |
| if mi_unlikely(size > PTRDIFF_MAX) { // we don't allocate more than PTRDIFF_MAX (see <https://sourceware.org/ml/libc-announce/2019/msg00001.html>) |
| #if MI_DEBUG > 0 |
| _mi_error_message(EOVERFLOW, "aligned allocation request is too large (size %zu, alignment %zu)\n", 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 && alignment <= padsize) { |
| 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, zero); // TODO: inline _mi_page_malloc |
| mi_assert_internal(p != NULL); |
| mi_assert_internal(((uintptr_t)p + offset) % alignment == 0); |
| mi_track_malloc(p,size,zero); |
| 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_nodiscard 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_nodiscard mi_decl_restrict void* mi_heap_malloc_aligned(mi_heap_t* heap, size_t size, size_t alignment) mi_attr_noexcept { |
| #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_nodiscard 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); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_heap_zalloc_aligned(mi_heap_t* heap, size_t size, size_t alignment) mi_attr_noexcept { |
| return mi_heap_zalloc_aligned_at(heap, size, alignment, 0); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_heap_calloc_aligned_at(mi_heap_t* heap, size_t count, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
| size_t total; |
| if (mi_count_size_overflow(count, size, &total)) return NULL; |
| return mi_heap_zalloc_aligned_at(heap, total, alignment, offset); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_heap_calloc_aligned(mi_heap_t* heap, size_t count, size_t size, size_t alignment) mi_attr_noexcept { |
| return mi_heap_calloc_aligned_at(heap,count,size,alignment,0); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_malloc_aligned_at(size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_malloc_aligned_at(mi_get_default_heap(), size, alignment, offset); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_malloc_aligned(size_t size, size_t alignment) mi_attr_noexcept { |
| return mi_heap_malloc_aligned(mi_get_default_heap(), size, alignment); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_zalloc_aligned_at(size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_zalloc_aligned_at(mi_get_default_heap(), size, alignment, offset); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_zalloc_aligned(size_t size, size_t alignment) mi_attr_noexcept { |
| return mi_heap_zalloc_aligned(mi_get_default_heap(), size, alignment); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_calloc_aligned_at(size_t count, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_calloc_aligned_at(mi_get_default_heap(), count, size, alignment, offset); |
| } |
| |
| mi_decl_nodiscard mi_decl_restrict void* mi_calloc_aligned(size_t count, size_t size, size_t alignment) mi_attr_noexcept { |
| return mi_heap_calloc_aligned(mi_get_default_heap(), count, size, alignment); |
| } |
| |
| |
| // ------------------------------------------------------ |
| // 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); |
| if (p == NULL) return mi_heap_malloc_zero_aligned_at(heap,newsize,alignment,offset,zero); |
| size_t size = mi_usable_size(p); |
| if (newsize <= size && newsize >= (size - (size / 2)) |
| && (((uintptr_t)p + offset) % alignment) == 0) { |
| return p; // reallocation still fits, is aligned and not more than 50% waste |
| } |
| else { |
| void* newp = mi_heap_malloc_aligned_at(heap,newsize,alignment,offset); |
| if (newp != NULL) { |
| if (zero && newsize > size) { |
| const mi_page_t* page = _mi_ptr_page(newp); |
| if (page->is_zero) { |
| // already zero initialized |
| mi_assert_expensive(mi_mem_is_zero(newp,newsize)); |
| } |
| else { |
| // also set last word in the previous allocation to zero to ensure any padding is zero-initialized |
| size_t start = (size >= sizeof(intptr_t) ? size - sizeof(intptr_t) : 0); |
| memset((uint8_t*)newp + start, 0, newsize - start); |
| } |
| } |
| _mi_memcpy_aligned(newp, p, (newsize > size ? size : newsize)); |
| mi_free(p); // only free if successful |
| } |
| return newp; |
| } |
| } |
| |
| static void* mi_heap_realloc_zero_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, bool zero) mi_attr_noexcept { |
| mi_assert(alignment > 0); |
| if (alignment <= sizeof(uintptr_t)) return _mi_heap_realloc_zero(heap,p,newsize,zero); |
| size_t offset = ((uintptr_t)p % alignment); // use offset of previous allocation (p can be NULL) |
| return mi_heap_realloc_zero_aligned_at(heap,p,newsize,alignment,offset,zero); |
| } |
| |
| mi_decl_nodiscard void* mi_heap_realloc_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_realloc_zero_aligned_at(heap,p,newsize,alignment,offset,false); |
| } |
| |
| mi_decl_nodiscard void* mi_heap_realloc_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
| return mi_heap_realloc_zero_aligned(heap,p,newsize,alignment,false); |
| } |
| |
| mi_decl_nodiscard void* mi_heap_rezalloc_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_realloc_zero_aligned_at(heap, p, newsize, alignment, offset, true); |
| } |
| |
| mi_decl_nodiscard void* mi_heap_rezalloc_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
| return mi_heap_realloc_zero_aligned(heap, p, newsize, alignment, true); |
| } |
| |
| mi_decl_nodiscard void* mi_heap_recalloc_aligned_at(mi_heap_t* heap, void* p, size_t newcount, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
| size_t total; |
| if (mi_count_size_overflow(newcount, size, &total)) return NULL; |
| return mi_heap_rezalloc_aligned_at(heap, p, total, alignment, offset); |
| } |
| |
| mi_decl_nodiscard void* mi_heap_recalloc_aligned(mi_heap_t* heap, void* p, size_t newcount, size_t size, size_t alignment) mi_attr_noexcept { |
| size_t total; |
| if (mi_count_size_overflow(newcount, size, &total)) return NULL; |
| return mi_heap_rezalloc_aligned(heap, p, total, alignment); |
| } |
| |
| mi_decl_nodiscard void* mi_realloc_aligned_at(void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_realloc_aligned_at(mi_get_default_heap(), p, newsize, alignment, offset); |
| } |
| |
| mi_decl_nodiscard void* mi_realloc_aligned(void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
| return mi_heap_realloc_aligned(mi_get_default_heap(), p, newsize, alignment); |
| } |
| |
| mi_decl_nodiscard void* mi_rezalloc_aligned_at(void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_rezalloc_aligned_at(mi_get_default_heap(), p, newsize, alignment, offset); |
| } |
| |
| mi_decl_nodiscard void* mi_rezalloc_aligned(void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
| return mi_heap_rezalloc_aligned(mi_get_default_heap(), p, newsize, alignment); |
| } |
| |
| mi_decl_nodiscard void* mi_recalloc_aligned_at(void* p, size_t newcount, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
| return mi_heap_recalloc_aligned_at(mi_get_default_heap(), p, newcount, size, alignment, offset); |
| } |
| |
| mi_decl_nodiscard void* mi_recalloc_aligned(void* p, size_t newcount, size_t size, size_t alignment) mi_attr_noexcept { |
| return mi_heap_recalloc_aligned(mi_get_default_heap(), p, newcount, size, alignment); |
| } |