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cpython/Objects/mimalloc/alloc.c

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/* ----------------------------------------------------------------------------
Copyright (c) 2018-2022, 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.
-----------------------------------------------------------------------------*/
#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE // for realpath() on Linux
#endif
#include "mimalloc.h"
#include "mimalloc/internal.h"
#include "mimalloc/atomic.h"
#include "mimalloc/prim.h" // _mi_prim_thread_id()
#include <string.h> // memset, strlen (for mi_strdup)
#include <stdlib.h> // malloc, abort
#define _ZSt15get_new_handlerv _Py__ZSt15get_new_handlerv
#define MI_IN_ALLOC_C
#include "alloc-override.c"
#undef MI_IN_ALLOC_C
// ------------------------------------------------------
// Allocation
// ------------------------------------------------------
#if (MI_DEBUG>0)
static inline void mi_debug_fill(mi_page_t* page, mi_block_t* block, int c, size_t size) {
size_t offset = (size_t)page->debug_offset;
if (offset < size) {
memset((char*)block + offset, c, size - offset);
}
}
#endif
// Fast allocation in a page: just pop from the free list.
// Fall back to generic allocation only if the list is empty.
extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size, bool zero) mi_attr_noexcept {
mi_assert_internal(page->xblock_size==0||mi_page_block_size(page) >= size);
mi_block_t* const block = page->free;
if mi_unlikely(block == NULL) {
return _mi_malloc_generic(heap, size, zero, 0);
}
mi_assert_internal(block != NULL && _mi_ptr_page(block) == page);
// pop from the free list
page->used++;
page->free = mi_block_next(page, block);
mi_assert_internal(page->free == NULL || _mi_ptr_page(page->free) == page);
#if MI_DEBUG>3
if (page->free_is_zero) {
mi_assert_expensive(mi_mem_is_zero(block+1,size - sizeof(*block)));
}
#endif
// allow use of the block internally
// note: when tracking we need to avoid ever touching the MI_PADDING since
// that is tracked by valgrind etc. as non-accessible (through the red-zone, see `mimalloc/track.h`)
mi_track_mem_undefined(block, mi_page_usable_block_size(page));
// zero the block? note: we need to zero the full block size (issue #63)
if mi_unlikely(zero) {
mi_assert_internal(page->xblock_size != 0); // do not call with zero'ing for huge blocks (see _mi_malloc_generic)
mi_assert_internal(page->xblock_size >= MI_PADDING_SIZE);
if (page->free_is_zero) {
block->next = 0;
mi_track_mem_defined(block, page->xblock_size - MI_PADDING_SIZE);
}
else {
_mi_memzero_aligned(block, page->xblock_size - MI_PADDING_SIZE);
}
}
#if (MI_DEBUG>0) && !MI_TRACK_ENABLED && !MI_TSAN
if (!zero && !mi_page_is_huge(page)) {
mi_debug_fill(page, block, MI_DEBUG_UNINIT, mi_page_usable_block_size(page));
}
#elif (MI_SECURE!=0)
if (!zero) { block->next = 0; } // don't leak internal data
#endif
#if (MI_STAT>0)
const size_t bsize = mi_page_usable_block_size(page);
if (bsize <= MI_MEDIUM_OBJ_SIZE_MAX) {
mi_heap_stat_increase(heap, normal, bsize);
mi_heap_stat_counter_increase(heap, normal_count, 1);
#if (MI_STAT>1)
const size_t bin = _mi_bin(bsize);
mi_heap_stat_increase(heap, normal_bins[bin], 1);
#endif
}
#endif
#if MI_PADDING // && !MI_TRACK_ENABLED
mi_padding_t* const padding = (mi_padding_t*)((uint8_t*)block + mi_page_usable_block_size(page));
ptrdiff_t delta = ((uint8_t*)padding - (uint8_t*)block - (size - MI_PADDING_SIZE));
#if (MI_DEBUG>=2)
mi_assert_internal(delta >= 0 && mi_page_usable_block_size(page) >= (size - MI_PADDING_SIZE + delta));
#endif
mi_track_mem_defined(padding,sizeof(mi_padding_t)); // note: re-enable since mi_page_usable_block_size may set noaccess
padding->canary = (uint32_t)(mi_ptr_encode(page,block,page->keys));
padding->delta = (uint32_t)(delta);
#if MI_PADDING_CHECK
if (!mi_page_is_huge(page)) {
uint8_t* fill = (uint8_t*)padding - delta;
const size_t maxpad = (delta > MI_MAX_ALIGN_SIZE ? MI_MAX_ALIGN_SIZE : delta); // set at most N initial padding bytes
for (size_t i = 0; i < maxpad; i++) { fill[i] = MI_DEBUG_PADDING; }
}
#endif
#endif
return block;
}
static inline mi_decl_restrict void* mi_heap_malloc_small_zero(mi_heap_t* heap, size_t size, bool zero) mi_attr_noexcept {
mi_assert(heap != NULL);
#if MI_DEBUG
const uintptr_t tid = _mi_thread_id();
mi_assert(heap->thread_id == 0 || heap->thread_id == tid); // heaps are thread local
#endif
mi_assert(size <= MI_SMALL_SIZE_MAX);
#if (MI_PADDING)
if (size == 0) { size = sizeof(void*); }
#endif
mi_page_t* page = _mi_heap_get_free_small_page(heap, size + MI_PADDING_SIZE);
void* const p = _mi_page_malloc(heap, page, size + MI_PADDING_SIZE, zero);
mi_track_malloc(p,size,zero);
#if MI_STAT>1
if (p != NULL) {
if (!mi_heap_is_initialized(heap)) { heap = mi_prim_get_default_heap(); }
mi_heap_stat_increase(heap, malloc, mi_usable_size(p));
}
#endif
#if MI_DEBUG>3
if (p != NULL && zero) {
mi_assert_expensive(mi_mem_is_zero(p, size));
}
#endif
return p;
}
// allocate a small block
mi_decl_nodiscard extern inline mi_decl_restrict void* mi_heap_malloc_small(mi_heap_t* heap, size_t size) mi_attr_noexcept {
return mi_heap_malloc_small_zero(heap, size, false);
}
mi_decl_nodiscard extern inline mi_decl_restrict void* mi_malloc_small(size_t size) mi_attr_noexcept {
return mi_heap_malloc_small(mi_prim_get_default_heap(), size);
}
// The main allocation function
extern inline void* _mi_heap_malloc_zero_ex(mi_heap_t* heap, size_t size, bool zero, size_t huge_alignment) mi_attr_noexcept {
if mi_likely(size <= MI_SMALL_SIZE_MAX) {
mi_assert_internal(huge_alignment == 0);
return mi_heap_malloc_small_zero(heap, size, zero);
}
else {
mi_assert(heap!=NULL);
mi_assert(heap->thread_id == 0 || heap->thread_id == _mi_thread_id()); // heaps are thread local
void* const p = _mi_malloc_generic(heap, size + MI_PADDING_SIZE, zero, huge_alignment); // note: size can overflow but it is detected in malloc_generic
mi_track_malloc(p,size,zero);
#if MI_STAT>1
if (p != NULL) {
if (!mi_heap_is_initialized(heap)) { heap = mi_prim_get_default_heap(); }
mi_heap_stat_increase(heap, malloc, mi_usable_size(p));
}
#endif
#if MI_DEBUG>3
if (p != NULL && zero) {
mi_assert_expensive(mi_mem_is_zero(p, size));
}
#endif
return p;
}
}
extern inline void* _mi_heap_malloc_zero(mi_heap_t* heap, size_t size, bool zero) mi_attr_noexcept {
return _mi_heap_malloc_zero_ex(heap, size, zero, 0);
}
mi_decl_nodiscard extern inline mi_decl_restrict void* mi_heap_malloc(mi_heap_t* heap, size_t size) mi_attr_noexcept {
return _mi_heap_malloc_zero(heap, size, false);
}
mi_decl_nodiscard extern inline mi_decl_restrict void* mi_malloc(size_t size) mi_attr_noexcept {
return mi_heap_malloc(mi_prim_get_default_heap(), size);
}
// zero initialized small block
mi_decl_nodiscard mi_decl_restrict void* mi_zalloc_small(size_t size) mi_attr_noexcept {
return mi_heap_malloc_small_zero(mi_prim_get_default_heap(), size, true);
}
mi_decl_nodiscard extern inline mi_decl_restrict void* mi_heap_zalloc(mi_heap_t* heap, size_t size) mi_attr_noexcept {
return _mi_heap_malloc_zero(heap, size, true);
}
mi_decl_nodiscard mi_decl_restrict void* mi_zalloc(size_t size) mi_attr_noexcept {
return mi_heap_zalloc(mi_prim_get_default_heap(),size);
}
// ------------------------------------------------------
// Check for double free in secure and debug mode
// This is somewhat expensive so only enabled for secure mode 4
// ------------------------------------------------------
#if (MI_ENCODE_FREELIST && (MI_SECURE>=4 || MI_DEBUG!=0))
// linear check if the free list contains a specific element
static bool mi_list_contains(const mi_page_t* page, const mi_block_t* list, const mi_block_t* elem) {
while (list != NULL) {
if (elem==list) return true;
list = mi_block_next(page, list);
}
return false;
}
static mi_decl_noinline bool mi_check_is_double_freex(const mi_page_t* page, const mi_block_t* block) {
// The decoded value is in the same page (or NULL).
// Walk the free lists to verify positively if it is already freed
if (mi_list_contains(page, page->free, block) ||
mi_list_contains(page, page->local_free, block) ||
mi_list_contains(page, mi_page_thread_free(page), block))
{
_mi_error_message(EAGAIN, "double free detected of block %p with size %zu\n", block, mi_page_block_size(page));
return true;
}
return false;
}
#define mi_track_page(page,access) { size_t psize; void* pstart = _mi_page_start(_mi_page_segment(page),page,&psize); mi_track_mem_##access( pstart, psize); }
static inline bool mi_check_is_double_free(const mi_page_t* page, const mi_block_t* block) {
bool is_double_free = false;
mi_block_t* n = mi_block_nextx(page, block, page->keys); // pretend it is freed, and get the decoded first field
if (((uintptr_t)n & (MI_INTPTR_SIZE-1))==0 && // quick check: aligned pointer?
(n==NULL || mi_is_in_same_page(block, n))) // quick check: in same page or NULL?
{
// Suspicious: decoded value a in block is in the same page (or NULL) -- maybe a double free?
// (continue in separate function to improve code generation)
is_double_free = mi_check_is_double_freex(page, block);
}
return is_double_free;
}
#else
static inline bool mi_check_is_double_free(const mi_page_t* page, const mi_block_t* block) {
MI_UNUSED(page);
MI_UNUSED(block);
return false;
}
#endif
// ---------------------------------------------------------------------------
// Check for heap block overflow by setting up padding at the end of the block
// ---------------------------------------------------------------------------
#if MI_PADDING // && !MI_TRACK_ENABLED
static bool mi_page_decode_padding(const mi_page_t* page, const mi_block_t* block, size_t* delta, size_t* bsize) {
*bsize = mi_page_usable_block_size(page);
const mi_padding_t* const padding = (mi_padding_t*)((uint8_t*)block + *bsize);
mi_track_mem_defined(padding,sizeof(mi_padding_t));
*delta = padding->delta;
uint32_t canary = padding->canary;
uintptr_t keys[2];
keys[0] = page->keys[0];
keys[1] = page->keys[1];
bool ok = ((uint32_t)mi_ptr_encode(page,block,keys) == canary && *delta <= *bsize);
mi_track_mem_noaccess(padding,sizeof(mi_padding_t));
return ok;
}
// Return the exact usable size of a block.
static size_t mi_page_usable_size_of(const mi_page_t* page, const mi_block_t* block) {
size_t bsize;
size_t delta;
bool ok = mi_page_decode_padding(page, block, &delta, &bsize);
mi_assert_internal(ok); mi_assert_internal(delta <= bsize);
return (ok ? bsize - delta : 0);
}
// When a non-thread-local block is freed, it becomes part of the thread delayed free
// list that is freed later by the owning heap. If the exact usable size is too small to
// contain the pointer for the delayed list, then shrink the padding (by decreasing delta)
// so it will later not trigger an overflow error in `mi_free_block`.
void _mi_padding_shrink(const mi_page_t* page, const mi_block_t* block, const size_t min_size) {
size_t bsize;
size_t delta;
bool ok = mi_page_decode_padding(page, block, &delta, &bsize);
mi_assert_internal(ok);
if (!ok || (bsize - delta) >= min_size) return; // usually already enough space
mi_assert_internal(bsize >= min_size);
if (bsize < min_size) return; // should never happen
size_t new_delta = (bsize - min_size);
mi_assert_internal(new_delta < bsize);
mi_padding_t* padding = (mi_padding_t*)((uint8_t*)block + bsize);
mi_track_mem_defined(padding,sizeof(mi_padding_t));
padding->delta = (uint32_t)new_delta;
mi_track_mem_noaccess(padding,sizeof(mi_padding_t));
}
#else
static size_t mi_page_usable_size_of(const mi_page_t* page, const mi_block_t* block) {
MI_UNUSED(block);
return mi_page_usable_block_size(page);
}
void _mi_padding_shrink(const mi_page_t* page, const mi_block_t* block, const size_t min_size) {
MI_UNUSED(page);
MI_UNUSED(block);
MI_UNUSED(min_size);
}
#endif
#if MI_PADDING && MI_PADDING_CHECK
static bool mi_verify_padding(const mi_page_t* page, const mi_block_t* block, size_t* size, size_t* wrong) {
size_t bsize;
size_t delta;
bool ok = mi_page_decode_padding(page, block, &delta, &bsize);
*size = *wrong = bsize;
if (!ok) return false;
mi_assert_internal(bsize >= delta);
*size = bsize - delta;
if (!mi_page_is_huge(page)) {
uint8_t* fill = (uint8_t*)block + bsize - delta;
const size_t maxpad = (delta > MI_MAX_ALIGN_SIZE ? MI_MAX_ALIGN_SIZE : delta); // check at most the first N padding bytes
mi_track_mem_defined(fill, maxpad);
for (size_t i = 0; i < maxpad; i++) {
if (fill[i] != MI_DEBUG_PADDING) {
*wrong = bsize - delta + i;
ok = false;
break;
}
}
mi_track_mem_noaccess(fill, maxpad);
}
return ok;
}
static void mi_check_padding(const mi_page_t* page, const mi_block_t* block) {
size_t size;
size_t wrong;
if (!mi_verify_padding(page,block,&size,&wrong)) {
_mi_error_message(EFAULT, "buffer overflow in heap block %p of size %zu: write after %zu bytes\n", block, size, wrong );
}
}
#else
static void mi_check_padding(const mi_page_t* page, const mi_block_t* block) {
MI_UNUSED(page);
MI_UNUSED(block);
}
#endif
// only maintain stats for smaller objects if requested
#if (MI_STAT>0)
static void mi_stat_free(const mi_page_t* page, const mi_block_t* block) {
#if (MI_STAT < 2)
MI_UNUSED(block);
#endif
mi_heap_t* const heap = mi_heap_get_default();
const size_t bsize = mi_page_usable_block_size(page);
#if (MI_STAT>1)
const size_t usize = mi_page_usable_size_of(page, block);
mi_heap_stat_decrease(heap, malloc, usize);
#endif
if (bsize <= MI_MEDIUM_OBJ_SIZE_MAX) {
mi_heap_stat_decrease(heap, normal, bsize);
#if (MI_STAT > 1)
mi_heap_stat_decrease(heap, normal_bins[_mi_bin(bsize)], 1);
#endif
}
else if (bsize <= MI_LARGE_OBJ_SIZE_MAX) {
mi_heap_stat_decrease(heap, large, bsize);
}
else {
mi_heap_stat_decrease(heap, huge, bsize);
}
}
#else
static void mi_stat_free(const mi_page_t* page, const mi_block_t* block) {
MI_UNUSED(page); MI_UNUSED(block);
}
#endif
#if MI_HUGE_PAGE_ABANDON
#if (MI_STAT>0)
// maintain stats for huge objects
static void mi_stat_huge_free(const mi_page_t* page) {
mi_heap_t* const heap = mi_heap_get_default();
const size_t bsize = mi_page_block_size(page); // to match stats in `page.c:mi_page_huge_alloc`
if (bsize <= MI_LARGE_OBJ_SIZE_MAX) {
mi_heap_stat_decrease(heap, large, bsize);
}
else {
mi_heap_stat_decrease(heap, huge, bsize);
}
}
#else
static void mi_stat_huge_free(const mi_page_t* page) {
MI_UNUSED(page);
}
#endif
#endif
// ------------------------------------------------------
// Free
// ------------------------------------------------------
// multi-threaded free (or free in huge block if compiled with MI_HUGE_PAGE_ABANDON)
static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* block)
{
// The padding check may access the non-thread-owned page for the key values.
// that is safe as these are constant and the page won't be freed (as the block is not freed yet).
mi_check_padding(page, block);
_mi_padding_shrink(page, block, sizeof(mi_block_t)); // for small size, ensure we can fit the delayed thread pointers without triggering overflow detection
// huge page segments are always abandoned and can be freed immediately
mi_segment_t* segment = _mi_page_segment(page);
if (segment->kind == MI_SEGMENT_HUGE) {
#if MI_HUGE_PAGE_ABANDON
// huge page segments are always abandoned and can be freed immediately
mi_stat_huge_free(page);
_mi_segment_huge_page_free(segment, page, block);
return;
#else
// huge pages are special as they occupy the entire segment
// as these are large we reset the memory occupied by the page so it is available to other threads
// (as the owning thread needs to actually free the memory later).
_mi_segment_huge_page_reset(segment, page, block);
#endif
}
#if (MI_DEBUG>0) && !MI_TRACK_ENABLED && !MI_TSAN // note: when tracking, cannot use mi_usable_size with multi-threading
if (segment->kind != MI_SEGMENT_HUGE) { // not for huge segments as we just reset the content
mi_debug_fill(page, block, MI_DEBUG_FREED, mi_usable_size(block));
}
#endif
// Try to put the block on either the page-local thread free list, or the heap delayed free list.
mi_thread_free_t tfreex;
bool use_delayed;
mi_thread_free_t tfree = mi_atomic_load_relaxed(&page->xthread_free);
do {
use_delayed = (mi_tf_delayed(tfree) == MI_USE_DELAYED_FREE);
if mi_unlikely(use_delayed) {
// unlikely: this only happens on the first concurrent free in a page that is in the full list
tfreex = mi_tf_set_delayed(tfree,MI_DELAYED_FREEING);
}
else {
// usual: directly add to page thread_free list
mi_block_set_next(page, block, mi_tf_block(tfree));
tfreex = mi_tf_set_block(tfree,block);
}
} while (!mi_atomic_cas_weak_release(&page->xthread_free, &tfree, tfreex));
if mi_unlikely(use_delayed) {
// racy read on `heap`, but ok because MI_DELAYED_FREEING is set (see `mi_heap_delete` and `mi_heap_collect_abandon`)
mi_heap_t* const heap = (mi_heap_t*)(mi_atomic_load_acquire(&page->xheap)); //mi_page_heap(page);
mi_assert_internal(heap != NULL);
if (heap != NULL) {
// add to the delayed free list of this heap. (do this atomically as the lock only protects heap memory validity)
mi_block_t* dfree = mi_atomic_load_ptr_relaxed(mi_block_t, &heap->thread_delayed_free);
do {
mi_block_set_nextx(heap,block,dfree, heap->keys);
} while (!mi_atomic_cas_ptr_weak_release(mi_block_t,&heap->thread_delayed_free, &dfree, block));
}
// and reset the MI_DELAYED_FREEING flag
tfree = mi_atomic_load_relaxed(&page->xthread_free);
do {
tfreex = tfree;
mi_assert_internal(mi_tf_delayed(tfree) == MI_DELAYED_FREEING);
tfreex = mi_tf_set_delayed(tfree,MI_NO_DELAYED_FREE);
} while (!mi_atomic_cas_weak_release(&page->xthread_free, &tfree, tfreex));
}
}
// regular free
static inline void _mi_free_block(mi_page_t* page, bool local, mi_block_t* block)
{
// and push it on the free list
//const size_t bsize = mi_page_block_size(page);
if mi_likely(local) {
// owning thread can free a block directly
if mi_unlikely(mi_check_is_double_free(page, block)) return;
mi_check_padding(page, block);
#if (MI_DEBUG>0) && !MI_TRACK_ENABLED && !MI_TSAN
if (!mi_page_is_huge(page)) { // huge page content may be already decommitted
mi_debug_fill(page, block, MI_DEBUG_FREED, mi_page_block_size(page));
}
#endif
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
page->used--;
if mi_unlikely(mi_page_all_free(page)) {
_mi_page_retire(page);
}
else if mi_unlikely(mi_page_is_in_full(page)) {
_mi_page_unfull(page);
}
}
else {
_mi_free_block_mt(page,block);
}
}
// Adjust a block that was allocated aligned, to the actual start of the block in the page.
mi_block_t* _mi_page_ptr_unalign(const mi_segment_t* segment, const mi_page_t* page, const void* p) {
mi_assert_internal(page!=NULL && p!=NULL);
const size_t diff = (uint8_t*)p - _mi_page_start(segment, page, NULL);
const size_t adjust = (diff % mi_page_block_size(page));
return (mi_block_t*)((uintptr_t)p - adjust);
}
void mi_decl_noinline _mi_free_generic(const mi_segment_t* segment, mi_page_t* page, bool is_local, void* p) mi_attr_noexcept {
mi_block_t* const block = (mi_page_has_aligned(page) ? _mi_page_ptr_unalign(segment, page, p) : (mi_block_t*)p);
mi_stat_free(page, block); // stat_free may access the padding
mi_track_free_size(block, mi_page_usable_size_of(page,block));
_mi_free_block(page, is_local, block);
}
// Get the segment data belonging to a pointer
// This is just a single `and` in assembly but does further checks in debug mode
// (and secure mode) if this was a valid pointer.
static inline mi_segment_t* mi_checked_ptr_segment(const void* p, const char* msg)
{
MI_UNUSED(msg);
mi_assert(p != NULL);
#if (MI_DEBUG>0)
if mi_unlikely(((uintptr_t)p & (MI_INTPTR_SIZE - 1)) != 0) {
_mi_error_message(EINVAL, "%s: invalid (unaligned) pointer: %p\n", msg, p);
return NULL;
}
#endif
mi_segment_t* const segment = _mi_ptr_segment(p);
mi_assert_internal(segment != NULL);
#if 0 && (MI_DEBUG>0)
if mi_unlikely(!mi_is_in_heap_region(p)) {
#if (MI_INTPTR_SIZE == 8 && defined(__linux__))
if (((uintptr_t)p >> 40) != 0x7F) { // linux tends to align large blocks above 0x7F000000000 (issue #640)
#else
{
#endif
_mi_warning_message("%s: pointer might not point to a valid heap region: %p\n"
"(this may still be a valid very large allocation (over 64MiB))\n", msg, p);
if mi_likely(_mi_ptr_cookie(segment) == segment->cookie) {
_mi_warning_message("(yes, the previous pointer %p was valid after all)\n", p);
}
}
}
#endif
#if (MI_DEBUG>0 || MI_SECURE>=4)
if mi_unlikely(_mi_ptr_cookie(segment) != segment->cookie) {
_mi_error_message(EINVAL, "%s: pointer does not point to a valid heap space: %p\n", msg, p);
return NULL;
}
#endif
return segment;
}
// Free a block
// fast path written carefully to prevent spilling on the stack
void mi_free(void* p) mi_attr_noexcept
{
if mi_unlikely(p == NULL) return;
mi_segment_t* const segment = mi_checked_ptr_segment(p,"mi_free");
const bool is_local= (_mi_prim_thread_id() == mi_atomic_load_relaxed(&segment->thread_id));
mi_page_t* const page = _mi_segment_page_of(segment, p);
if mi_likely(is_local) { // thread-local free?
if mi_likely(page->flags.full_aligned == 0) // and it is not a full page (full pages need to move from the full bin), nor has aligned blocks (aligned blocks need to be unaligned)
{
mi_block_t* const block = (mi_block_t*)p;
if mi_unlikely(mi_check_is_double_free(page, block)) return;
mi_check_padding(page, block);
mi_stat_free(page, block);
#if (MI_DEBUG>0) && !MI_TRACK_ENABLED && !MI_TSAN
mi_debug_fill(page, block, MI_DEBUG_FREED, mi_page_block_size(page));
#endif
mi_track_free_size(p, mi_page_usable_size_of(page,block)); // faster then mi_usable_size as we already know the page and that p is unaligned
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
if mi_unlikely(--page->used == 0) { // using this expression generates better code than: page->used--; if (mi_page_all_free(page))
_mi_page_retire(page);
}
}
else {
// page is full or contains (inner) aligned blocks; use generic path
_mi_free_generic(segment, page, true, p);
}
}
else {
// not thread-local; use generic path
_mi_free_generic(segment, page, false, p);
}
}
// return true if successful
bool _mi_free_delayed_block(mi_block_t* block) {
// get segment and page
const mi_segment_t* const segment = _mi_ptr_segment(block);
mi_assert_internal(_mi_ptr_cookie(segment) == segment->cookie);
#ifndef Py_GIL_DISABLED
// The GC traverses heaps of other threads, which can trigger this assert.
mi_assert_internal(_mi_thread_id() == segment->thread_id);
#endif
mi_page_t* const page = _mi_segment_page_of(segment, block);
// Clear the no-delayed flag so delayed freeing is used again for this page.
// This must be done before collecting the free lists on this page -- otherwise
// some blocks may end up in the page `thread_free` list with no blocks in the
// heap `thread_delayed_free` list which may cause the page to be never freed!
// (it would only be freed if we happen to scan it in `mi_page_queue_find_free_ex`)
if (!_mi_page_try_use_delayed_free(page, MI_USE_DELAYED_FREE, false /* dont overwrite never delayed */)) {
return false;
}
// collect all other non-local frees to ensure up-to-date `used` count
_mi_page_free_collect(page, false);
// and free the block (possibly freeing the page as well since used is updated)
_mi_free_block(page, true, block);
return true;
}
// Bytes available in a block
mi_decl_noinline static size_t mi_page_usable_aligned_size_of(const mi_segment_t* segment, const mi_page_t* page, const void* p) mi_attr_noexcept {
const mi_block_t* block = _mi_page_ptr_unalign(segment, page, p);
const size_t size = mi_page_usable_size_of(page, block);
const ptrdiff_t adjust = (uint8_t*)p - (uint8_t*)block;
mi_assert_internal(adjust >= 0 && (size_t)adjust <= size);
return (size - adjust);
}
static inline size_t _mi_usable_size(const void* p, const char* msg) mi_attr_noexcept {
if (p == NULL) return 0;
const mi_segment_t* const segment = mi_checked_ptr_segment(p, msg);
const mi_page_t* const page = _mi_segment_page_of(segment, p);
if mi_likely(!mi_page_has_aligned(page)) {
const mi_block_t* block = (const mi_block_t*)p;
return mi_page_usable_size_of(page, block);
}
else {
// split out to separate routine for improved code generation
return mi_page_usable_aligned_size_of(segment, page, p);
}
}
mi_decl_nodiscard size_t mi_usable_size(const void* p) mi_attr_noexcept {
return _mi_usable_size(p, "mi_usable_size");
}
// ------------------------------------------------------
// Allocation extensions
// ------------------------------------------------------
void mi_free_size(void* p, size_t size) mi_attr_noexcept {
MI_UNUSED_RELEASE(size);
mi_assert(p == NULL || size <= _mi_usable_size(p,"mi_free_size"));
mi_free(p);
}
void mi_free_size_aligned(void* p, size_t size, size_t alignment) mi_attr_noexcept {
MI_UNUSED_RELEASE(alignment);
mi_assert(((uintptr_t)p % alignment) == 0);
mi_free_size(p,size);
}
void mi_free_aligned(void* p, size_t alignment) mi_attr_noexcept {
MI_UNUSED_RELEASE(alignment);
mi_assert(((uintptr_t)p % alignment) == 0);
mi_free(p);
}
mi_decl_nodiscard extern inline mi_decl_restrict void* mi_heap_calloc(mi_heap_t* heap, size_t count, size_t size) mi_attr_noexcept {
size_t total;
if (mi_count_size_overflow(count,size,&total)) return NULL;
return mi_heap_zalloc(heap,total);
}
mi_decl_nodiscard mi_decl_restrict void* mi_calloc(size_t count, size_t size) mi_attr_noexcept {
return mi_heap_calloc(mi_prim_get_default_heap(),count,size);
}
// Uninitialized `calloc`
mi_decl_nodiscard extern mi_decl_restrict void* mi_heap_mallocn(mi_heap_t* heap, size_t count, size_t size) mi_attr_noexcept {
size_t total;
if (mi_count_size_overflow(count, size, &total)) return NULL;
return mi_heap_malloc(heap, total);
}
mi_decl_nodiscard mi_decl_restrict void* mi_mallocn(size_t count, size_t size) mi_attr_noexcept {
return mi_heap_mallocn(mi_prim_get_default_heap(),count,size);
}
// Expand (or shrink) in place (or fail)
void* mi_expand(void* p, size_t newsize) mi_attr_noexcept {
#if MI_PADDING
// we do not shrink/expand with padding enabled
MI_UNUSED(p); MI_UNUSED(newsize);
return NULL;
#else
if (p == NULL) return NULL;
const size_t size = _mi_usable_size(p,"mi_expand");
if (newsize > size) return NULL;
return p; // it fits
#endif
}
void* _mi_heap_realloc_zero(mi_heap_t* heap, void* p, size_t newsize, bool zero) mi_attr_noexcept {
// if p == NULL then behave as malloc.
// else if size == 0 then reallocate to a zero-sized block (and don't return NULL, just as mi_malloc(0)).
// (this means that returning NULL always indicates an error, and `p` will not have been freed in that case.)
const size_t size = _mi_usable_size(p,"mi_realloc"); // also works if p == NULL (with size 0)
if mi_unlikely(newsize <= size && newsize >= (size / 2) && newsize > 0) { // note: newsize must be > 0 or otherwise we return NULL for realloc(NULL,0)
mi_assert_internal(p!=NULL);
// todo: do not track as the usable size is still the same in the free; adjust potential padding?
// mi_track_resize(p,size,newsize)
// if (newsize < size) { mi_track_mem_noaccess((uint8_t*)p + newsize, size - newsize); }
return p; // reallocation still fits and not more than 50% waste
}
void* newp = mi_heap_malloc(heap,newsize);
if mi_likely(newp != NULL) {
if (zero && newsize > size) {
// also set last word in the previous allocation to zero to ensure any padding is zero-initialized
const size_t start = (size >= sizeof(intptr_t) ? size - sizeof(intptr_t) : 0);
_mi_memzero((uint8_t*)newp + start, newsize - start);
}
else if (newsize == 0) {
((uint8_t*)newp)[0] = 0; // work around for applications that expect zero-reallocation to be zero initialized (issue #725)
}
if mi_likely(p != NULL) {
const size_t copysize = (newsize > size ? size : newsize);
mi_track_mem_defined(p,copysize); // _mi_useable_size may be too large for byte precise memory tracking..
_mi_memcpy(newp, p, copysize);
mi_free(p); // only free the original pointer if successful
}
}
return newp;
}
mi_decl_nodiscard void* mi_heap_realloc(mi_heap_t* heap, void* p, size_t newsize) mi_attr_noexcept {
return _mi_heap_realloc_zero(heap, p, newsize, false);
}
mi_decl_nodiscard void* mi_heap_reallocn(mi_heap_t* heap, void* p, size_t count, size_t size) mi_attr_noexcept {
size_t total;
if (mi_count_size_overflow(count, size, &total)) return NULL;
return mi_heap_realloc(heap, p, total);
}
// Reallocate but free `p` on errors
mi_decl_nodiscard void* mi_heap_reallocf(mi_heap_t* heap, void* p, size_t newsize) mi_attr_noexcept {
void* newp = mi_heap_realloc(heap, p, newsize);
if (newp==NULL && p!=NULL) mi_free(p);
return newp;
}
mi_decl_nodiscard void* mi_heap_rezalloc(mi_heap_t* heap, void* p, size_t newsize) mi_attr_noexcept {
return _mi_heap_realloc_zero(heap, p, newsize, true);
}
mi_decl_nodiscard void* mi_heap_recalloc(mi_heap_t* heap, void* p, size_t count, size_t size) mi_attr_noexcept {
size_t total;
if (mi_count_size_overflow(count, size, &total)) return NULL;
return mi_heap_rezalloc(heap, p, total);
}
mi_decl_nodiscard void* mi_realloc(void* p, size_t newsize) mi_attr_noexcept {
return mi_heap_realloc(mi_prim_get_default_heap(),p,newsize);
}
mi_decl_nodiscard void* mi_reallocn(void* p, size_t count, size_t size) mi_attr_noexcept {
return mi_heap_reallocn(mi_prim_get_default_heap(),p,count,size);
}
// Reallocate but free `p` on errors
mi_decl_nodiscard void* mi_reallocf(void* p, size_t newsize) mi_attr_noexcept {
return mi_heap_reallocf(mi_prim_get_default_heap(),p,newsize);
}
mi_decl_nodiscard void* mi_rezalloc(void* p, size_t newsize) mi_attr_noexcept {
return mi_heap_rezalloc(mi_prim_get_default_heap(), p, newsize);
}
mi_decl_nodiscard void* mi_recalloc(void* p, size_t count, size_t size) mi_attr_noexcept {
return mi_heap_recalloc(mi_prim_get_default_heap(), p, count, size);
}
// ------------------------------------------------------
// strdup, strndup, and realpath
// ------------------------------------------------------
// `strdup` using mi_malloc
mi_decl_nodiscard mi_decl_restrict char* mi_heap_strdup(mi_heap_t* heap, const char* s) mi_attr_noexcept {
if (s == NULL) return NULL;
size_t n = strlen(s);
char* t = (char*)mi_heap_malloc(heap,n+1);
if (t == NULL) return NULL;
_mi_memcpy(t, s, n);
t[n] = 0;
return t;
}
mi_decl_nodiscard mi_decl_restrict char* mi_strdup(const char* s) mi_attr_noexcept {
return mi_heap_strdup(mi_prim_get_default_heap(), s);
}
// `strndup` using mi_malloc
mi_decl_nodiscard mi_decl_restrict char* mi_heap_strndup(mi_heap_t* heap, const char* s, size_t n) mi_attr_noexcept {
if (s == NULL) return NULL;
const char* end = (const char*)memchr(s, 0, n); // find end of string in the first `n` characters (returns NULL if not found)
const size_t m = (end != NULL ? (size_t)(end - s) : n); // `m` is the minimum of `n` or the end-of-string
mi_assert_internal(m <= n);
char* t = (char*)mi_heap_malloc(heap, m+1);
if (t == NULL) return NULL;
_mi_memcpy(t, s, m);
t[m] = 0;
return t;
}
mi_decl_nodiscard mi_decl_restrict char* mi_strndup(const char* s, size_t n) mi_attr_noexcept {
return mi_heap_strndup(mi_prim_get_default_heap(),s,n);
}
#ifndef __wasi__
// `realpath` using mi_malloc
#ifdef _WIN32
#ifndef PATH_MAX
#define PATH_MAX MAX_PATH
#endif
#include <windows.h>
mi_decl_nodiscard mi_decl_restrict char* mi_heap_realpath(mi_heap_t* heap, const char* fname, char* resolved_name) mi_attr_noexcept {
// todo: use GetFullPathNameW to allow longer file names
char buf[PATH_MAX];
DWORD res = GetFullPathNameA(fname, PATH_MAX, (resolved_name == NULL ? buf : resolved_name), NULL);
if (res == 0) {
errno = GetLastError(); return NULL;
}
else if (res > PATH_MAX) {
errno = EINVAL; return NULL;
}
else if (resolved_name != NULL) {
return resolved_name;
}
else {
return mi_heap_strndup(heap, buf, PATH_MAX);
}
}
#else
/*
#include <unistd.h> // pathconf
static size_t mi_path_max(void) {
static size_t path_max = 0;
if (path_max <= 0) {
long m = pathconf("/",_PC_PATH_MAX);
if (m <= 0) path_max = 4096; // guess
else if (m < 256) path_max = 256; // at least 256
else path_max = m;
}
return path_max;
}
*/
char* mi_heap_realpath(mi_heap_t* heap, const char* fname, char* resolved_name) mi_attr_noexcept {
if (resolved_name != NULL) {
return realpath(fname,resolved_name);
}
else {
char* rname = realpath(fname, NULL);
if (rname == NULL) return NULL;
char* result = mi_heap_strdup(heap, rname);
free(rname); // use regular free! (which may be redirected to our free but that's ok)
return result;
}
/*
const size_t n = mi_path_max();
char* buf = (char*)mi_malloc(n+1);
if (buf == NULL) {
errno = ENOMEM;
return NULL;
}
char* rname = realpath(fname,buf);
char* result = mi_heap_strndup(heap,rname,n); // ok if `rname==NULL`
mi_free(buf);
return result;
}
*/
}
#endif
mi_decl_nodiscard mi_decl_restrict char* mi_realpath(const char* fname, char* resolved_name) mi_attr_noexcept {
return mi_heap_realpath(mi_prim_get_default_heap(),fname,resolved_name);
}
#endif
/*-------------------------------------------------------
C++ new and new_aligned
The standard requires calling into `get_new_handler` and
throwing the bad_alloc exception on failure. If we compile
with a C++ compiler we can implement this precisely. If we
use a C compiler we cannot throw a `bad_alloc` exception
but we call `exit` instead (i.e. not returning).
-------------------------------------------------------*/
#ifdef __cplusplus
#include <new>
static bool mi_try_new_handler(bool nothrow) {
#if defined(_MSC_VER) || (__cplusplus >= 201103L)
std::new_handler h = std::get_new_handler();
#else
std::new_handler h = std::set_new_handler();
std::set_new_handler(h);
#endif
if (h==NULL) {
_mi_error_message(ENOMEM, "out of memory in 'new'");
if (!nothrow) {
throw std::bad_alloc();
}
return false;
}
else {
h();
return true;
}
}
#else
typedef void (*std_new_handler_t)(void);
#if (defined(__GNUC__) || (defined(__clang__) && !defined(_MSC_VER))) // exclude clang-cl, see issue #631
std_new_handler_t __attribute__((weak)) _ZSt15get_new_handlerv(void) {
return NULL;
}
static std_new_handler_t mi_get_new_handler(void) {
return _ZSt15get_new_handlerv();
}
#else
// note: on windows we could dynamically link to `?get_new_handler@std@@YAP6AXXZXZ`.
static std_new_handler_t mi_get_new_handler() {
return NULL;
}
#endif
static bool mi_try_new_handler(bool nothrow) {
std_new_handler_t h = mi_get_new_handler();
if (h==NULL) {
_mi_error_message(ENOMEM, "out of memory in 'new'");
if (!nothrow) {
abort(); // cannot throw in plain C, use abort
}
return false;
}
else {
h();
return true;
}
}
#endif
mi_decl_export mi_decl_noinline void* mi_heap_try_new(mi_heap_t* heap, size_t size, bool nothrow ) {
void* p = NULL;
while(p == NULL && mi_try_new_handler(nothrow)) {
p = mi_heap_malloc(heap,size);
}
return p;
}
static mi_decl_noinline void* mi_try_new(size_t size, bool nothrow) {
return mi_heap_try_new(mi_prim_get_default_heap(), size, nothrow);
}
mi_decl_nodiscard mi_decl_restrict void* mi_heap_alloc_new(mi_heap_t* heap, size_t size) {
void* p = mi_heap_malloc(heap,size);
if mi_unlikely(p == NULL) return mi_heap_try_new(heap, size, false);
return p;
}
mi_decl_nodiscard mi_decl_restrict void* mi_new(size_t size) {
return mi_heap_alloc_new(mi_prim_get_default_heap(), size);
}
mi_decl_nodiscard mi_decl_restrict void* mi_heap_alloc_new_n(mi_heap_t* heap, size_t count, size_t size) {
size_t total;
if mi_unlikely(mi_count_size_overflow(count, size, &total)) {
mi_try_new_handler(false); // on overflow we invoke the try_new_handler once to potentially throw std::bad_alloc
return NULL;
}
else {
return mi_heap_alloc_new(heap,total);
}
}
mi_decl_nodiscard mi_decl_restrict void* mi_new_n(size_t count, size_t size) {
return mi_heap_alloc_new_n(mi_prim_get_default_heap(), size, count);
}
mi_decl_nodiscard mi_decl_restrict void* mi_new_nothrow(size_t size) mi_attr_noexcept {
void* p = mi_malloc(size);
if mi_unlikely(p == NULL) return mi_try_new(size, true);
return p;
}
mi_decl_nodiscard mi_decl_restrict void* mi_new_aligned(size_t size, size_t alignment) {
void* p;
do {
p = mi_malloc_aligned(size, alignment);
}
while(p == NULL && mi_try_new_handler(false));
return p;
}
mi_decl_nodiscard mi_decl_restrict void* mi_new_aligned_nothrow(size_t size, size_t alignment) mi_attr_noexcept {
void* p;
do {
p = mi_malloc_aligned(size, alignment);
}
while(p == NULL && mi_try_new_handler(true));
return p;
}
mi_decl_nodiscard void* mi_new_realloc(void* p, size_t newsize) {
void* q;
do {
q = mi_realloc(p, newsize);
} while (q == NULL && mi_try_new_handler(false));
return q;
}
mi_decl_nodiscard void* mi_new_reallocn(void* p, size_t newcount, size_t size) {
size_t total;
if mi_unlikely(mi_count_size_overflow(newcount, size, &total)) {
mi_try_new_handler(false); // on overflow we invoke the try_new_handler once to potentially throw std::bad_alloc
return NULL;
}
else {
return mi_new_realloc(p, total);
}
}
// ------------------------------------------------------
// ensure explicit external inline definitions are emitted!
// ------------------------------------------------------
#ifdef __cplusplus
void* _mi_externs[] = {
(void*)&_mi_page_malloc,
(void*)&_mi_heap_malloc_zero,
(void*)&_mi_heap_malloc_zero_ex,
(void*)&mi_malloc,
(void*)&mi_malloc_small,
(void*)&mi_zalloc_small,
(void*)&mi_heap_malloc,
(void*)&mi_heap_zalloc,
(void*)&mi_heap_malloc_small,
// (void*)&mi_heap_alloc_new,
// (void*)&mi_heap_alloc_new_n
};
#endif
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