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https://github.com/microsoft/mimalloc.git
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174 lines
8 KiB
C
174 lines
8 KiB
C
/* ----------------------------------------------------------------------------
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Copyright (c) 2018, Microsoft Research, Daan Leijen
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This is free software; you can redistribute it and/or modify it under the
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terms of the MIT license. A copy of the license can be found in the file
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"LICENSE" at the root of this distribution.
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-----------------------------------------------------------------------------*/
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#define MI_DEBUG_NO_SOURCE_LOC
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#include "mimalloc.h"
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#include "mimalloc-internal.h"
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#include <string.h> // memset, memcpy
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// ------------------------------------------------------
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// Aligned Allocation
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// ------------------------------------------------------
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static mi_decl_restrict void* mi_base_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_SOURCE_XPARAM) mi_attr_noexcept {
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// note: we don't require `size > offset`, we just guarantee that
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// the address at offset is aligned regardless of the allocated size.
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mi_assert(alignment > 0 && alignment % sizeof(void*) == 0);
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if (mi_unlikely(size > PTRDIFF_MAX)) return NULL; // we don't allocate more than PTRDIFF_MAX (see <https://sourceware.org/ml/libc-announce/2019/msg00001.html>)
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if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) return NULL; // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>)
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if (alignment <= MI_MAX_ALIGN_SIZE && offset==0) return _mi_base_malloc_zero(heap, size, zero MI_SOURCE_XARG);
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const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)`
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// try if there is a small block available with just the right alignment
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const size_t padsize = size + MI_PADDING_SIZE;
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if (mi_likely(padsize <= MI_SMALL_SIZE_MAX)) {
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mi_page_t* page = _mi_heap_get_free_small_page(heap,padsize);
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const bool is_aligned = (((uintptr_t)page->free+offset) & align_mask)==0;
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if (mi_likely(page->free != NULL && is_aligned))
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{
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#if MI_STAT>1
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mi_heap_stat_increase( heap, malloc, size);
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#endif
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void* p = _mi_page_malloc(heap,page,padsize MI_SOURCE_XARG); // TODO: inline _mi_page_malloc
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mi_assert_internal(p != NULL);
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mi_assert_internal(((uintptr_t)p + offset) % alignment == 0);
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if (zero) _mi_block_zero_init(page,p,size);
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return p;
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}
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}
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// use regular allocation if it is guaranteed to fit the alignment constraints
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if (offset==0 && alignment<=padsize && padsize<=MI_MEDIUM_OBJ_SIZE_MAX && (padsize&align_mask)==0) {
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void* p = _mi_base_malloc_zero(heap, size, zero MI_SOURCE_XARG);
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mi_assert_internal(p == NULL || ((uintptr_t)p % alignment) == 0);
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return p;
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}
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// otherwise over-allocate
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void* p = _mi_base_malloc_zero(heap, size + alignment - 1, zero MI_SOURCE_XARG);
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if (p == NULL) return NULL;
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// .. and align within the allocation
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uintptr_t adjust = alignment - (((uintptr_t)p + offset) & align_mask);
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mi_assert_internal(adjust % sizeof(uintptr_t) == 0);
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void* aligned_p = (adjust == alignment ? p : (void*)((uintptr_t)p + adjust));
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if (aligned_p != p) mi_page_set_has_aligned(_mi_ptr_page(p), true);
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mi_assert_internal(((uintptr_t)aligned_p + offset) % alignment == 0);
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mi_assert_internal( p == _mi_page_ptr_unalign(_mi_ptr_segment(aligned_p),_mi_ptr_page(aligned_p),aligned_p) );
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return aligned_p;
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}
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MI_ALLOC_API3(mi_decl_restrict void*, malloc_aligned_at, mi_heap_t*, heap, size_t, size, size_t, alignment, size_t, offset)
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{
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return mi_base_malloc_zero_aligned_at(heap, size, alignment, offset, false MI_SOURCE_XARG);
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}
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MI_ALLOC_API2(mi_decl_restrict void*, malloc_aligned, mi_heap_t*,heap, size_t, size, size_t, alignment)
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{
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return mi_base_malloc_zero_aligned_at(heap, size, alignment, 0, false MI_SOURCE_XARG);
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}
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MI_ALLOC_API3(mi_decl_restrict void*, zalloc_aligned_at, mi_heap_t*, heap, size_t, size, size_t, alignment, size_t, offset)
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{
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return mi_base_malloc_zero_aligned_at(heap, size, alignment, offset, true MI_SOURCE_XARG);
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}
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MI_ALLOC_API2(mi_decl_restrict void*, zalloc_aligned, mi_heap_t*,heap, size_t, size, size_t, alignment)
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{
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return mi_base_malloc_zero_aligned_at(heap, size, alignment, 0, true MI_SOURCE_XARG);
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}
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MI_ALLOC_API4(mi_decl_restrict void*, calloc_aligned_at, mi_heap_t*, heap, size_t, count, size_t, size, size_t, alignment, size_t, offset)
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{
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size_t total;
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if (mi_count_size_overflow(count, size, &total)) return NULL;
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return mi_base_malloc_zero_aligned_at(heap, total, alignment, offset, true MI_SOURCE_XARG);
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}
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MI_ALLOC_API3(mi_decl_restrict void*, calloc_aligned, mi_heap_t*, heap, size_t, count, size_t, size, size_t, alignment)
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{
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size_t total;
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if (mi_count_size_overflow(count, size, &total)) return NULL;
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return mi_base_malloc_zero_aligned_at(heap, total, alignment, 0, true MI_SOURCE_XARG);
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}
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static void* mi_base_realloc_zero_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset, bool zero MI_SOURCE_XPARAM) mi_attr_noexcept {
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mi_assert(alignment > 0);
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if (alignment <= sizeof(uintptr_t)) return _mi_base_realloc_zero(heap,p,newsize,zero MI_SOURCE_XARG);
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if (p == NULL) return mi_base_malloc_zero_aligned_at(heap,newsize,alignment,offset,zero MI_SOURCE_XARG);
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size_t size = mi_usable_size(p);
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if (newsize <= size && newsize >= (size - (size / 2))
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&& (((uintptr_t)p + offset) % alignment) == 0) {
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return p; // reallocation still fits, is aligned and not more than 50% waste
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}
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else {
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void* newp = mi_base_malloc_aligned_at(heap,newsize,alignment,offset MI_SOURCE_XARG);
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if (newp != NULL) {
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if (zero && newsize > size) {
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const mi_page_t* page = _mi_ptr_page(newp);
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if (page->is_zero) {
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// already zero initialized
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mi_assert_expensive(mi_mem_is_zero(newp,newsize));
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}
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else {
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// also set last word in the previous allocation to zero to ensure any padding is zero-initialized
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size_t start = (size >= sizeof(intptr_t) ? size - sizeof(intptr_t) : 0);
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memset((uint8_t*)newp + start, 0, newsize - start);
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}
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}
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memcpy(newp, p, (newsize > size ? size : newsize));
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mi_free(p); // only free if successful
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}
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return newp;
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}
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}
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static void* mi_base_realloc_zero_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, bool zero MI_SOURCE_XPARAM) mi_attr_noexcept {
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mi_assert(alignment > 0);
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if (alignment <= sizeof(uintptr_t)) return _mi_base_realloc_zero(heap,p,newsize,zero MI_SOURCE_XARG);
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size_t offset = ((uintptr_t)p % alignment); // use offset of previous allocation (p can be NULL)
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return mi_base_realloc_zero_aligned_at(heap,p,newsize,alignment,offset,zero MI_SOURCE_XARG);
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}
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MI_ALLOC_API4(void*, realloc_aligned_at, mi_heap_t*, heap, void*, p, size_t, newsize, size_t, alignment, size_t, offset)
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{
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return mi_base_realloc_zero_aligned_at(heap,p,newsize,alignment,offset,false MI_SOURCE_XARG);
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}
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MI_ALLOC_API3(void*, realloc_aligned, mi_heap_t*, heap, void*, p, size_t, newsize, size_t, alignment)
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{
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return mi_base_realloc_zero_aligned(heap,p,newsize,alignment,false MI_SOURCE_XARG);
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}
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MI_ALLOC_API4(void*, rezalloc_aligned_at, mi_heap_t*, heap, void*, p, size_t, newsize, size_t, alignment, size_t, offset)
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{
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return mi_base_realloc_zero_aligned_at(heap, p, newsize, alignment, offset, true MI_SOURCE_XARG);
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}
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MI_ALLOC_API3(void*, rezalloc_aligned, mi_heap_t*, heap, void*, p, size_t, newsize, size_t, alignment)
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{
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return mi_base_realloc_zero_aligned(heap, p, newsize, alignment, true MI_SOURCE_XARG);
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}
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MI_ALLOC_API5(void*, recalloc_aligned_at, mi_heap_t*, heap, void*, p, size_t, newcount, size_t, size, size_t, alignment, size_t, offset)
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{
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size_t total;
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if (mi_count_size_overflow(newcount, size, &total)) return NULL;
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return mi_base_realloc_zero_aligned_at(heap, p, total, alignment, offset, true MI_SOURCE_XARG);
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}
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MI_ALLOC_API4(void*, recalloc_aligned, mi_heap_t*, heap, void*, p, size_t, newcount, size_t, size, size_t, alignment)
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{
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size_t total;
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if (mi_count_size_overflow(newcount, size, &total)) return NULL;
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return mi_base_realloc_zero_aligned_at(heap, p, total, alignment, 0, true MI_SOURCE_XARG);
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}
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