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update guarded implementation to use block tags

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This commit is contained in:
daanx 2024-11-16 21:15:50 -08:00
parent 0e76fe3798
commit 498c92e348
11 changed files with 161 additions and 108 deletions
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63
src/free.c
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@ -70,20 +70,29 @@ mi_block_t* _mi_page_ptr_unalign(const mi_page_t* page, const void* p) {
}
// forward declaration for a MI_DEBUG_GUARDED build
static void mi_block_unguard(mi_page_t* page, mi_block_t* block);
#if MI_DEBUG_GUARDED
static void mi_block_unguard_prim(mi_page_t* page, mi_block_t* block, void* p); // forward declaration
static inline void mi_block_unguard(mi_page_t* page, mi_block_t* block, void* p) {
if (mi_block_ptr_is_guarded(block, p)) { mi_block_unguard_prim(page, block, p); }
}
#else
static inline void mi_block_unguard(mi_page_t* page, mi_block_t* block, void* p) {
MI_UNUSED(page); MI_UNUSED(block); MI_UNUSED(p);
}
#endif
// free a local pointer (page parameter comes first for better codegen)
static void mi_decl_noinline mi_free_generic_local(mi_page_t* page, mi_segment_t* segment, void* p) mi_attr_noexcept {
MI_UNUSED(segment);
mi_block_t* const block = (mi_page_has_aligned(page) ? _mi_page_ptr_unalign(page, p) : (mi_block_t*)p);
mi_block_unguard(page,block);
mi_block_unguard(page, block, p);
mi_free_block_local(page, block, true /* track stats */, true /* check for a full page */);
}
// free a pointer owned by another thread (page parameter comes first for better codegen)
static void mi_decl_noinline mi_free_generic_mt(mi_page_t* page, mi_segment_t* segment, void* p) mi_attr_noexcept {
mi_block_t* const block = _mi_page_ptr_unalign(page, p); // don't check `has_aligned` flag to avoid a race (issue #865)
mi_block_unguard(page, block);
mi_block_unguard(page, block, p);
mi_free_block_mt(page, segment, block);
}
@ -297,20 +306,19 @@ static size_t mi_decl_noinline mi_page_usable_aligned_size_of(const mi_page_t* 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);
const size_t aligned_size = (size - adjust);
#if MI_DEBUG_GUARDED
if (mi_block_ptr_is_guarded(block, p)) {
return aligned_size - _mi_os_page_size();
}
#endif
return aligned_size;
}
static inline size_t _mi_usable_size(const void* p, const char* msg) mi_attr_noexcept {
const mi_segment_t* const segment = mi_checked_ptr_segment(p, msg);
if mi_unlikely(segment==NULL) return 0;
const mi_page_t* const page = _mi_segment_page_of(segment, p);
#if MI_DEBUG_GUARDED
if (mi_page_has_guarded(page)) {
const size_t bsize = mi_page_usable_aligned_size_of(page, p);
mi_assert_internal(bsize > _mi_os_page_size());
return (bsize > _mi_os_page_size() ? bsize - _mi_os_page_size() : bsize);
} else
#endif
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);
@ -534,22 +542,19 @@ static void mi_stat_free(const mi_page_t* page, const mi_block_t* block) {
// Remove guard page when building with MI_DEBUG_GUARDED
#if !MI_DEBUG_GUARDED
static void mi_block_unguard(mi_page_t* page, mi_block_t* block) {
MI_UNUSED(page);
MI_UNUSED(block);
// do nothing
}
#else
static void mi_block_unguard(mi_page_t* page, mi_block_t* block) {
if (mi_page_has_guarded(page)) {
const size_t bsize = mi_page_block_size(page);
const size_t psize = _mi_os_page_size();
mi_assert_internal(bsize > psize);
mi_assert_internal(_mi_page_segment(page)->allow_decommit);
void* gpage = (uint8_t*)block + (bsize - psize);
mi_assert_internal(_mi_is_aligned(gpage, psize));
_mi_os_unprotect(gpage, psize);
}
#if MI_DEBUG_GUARDED
static void mi_block_unguard_prim(mi_page_t* page, mi_block_t* block, void* p) {
mi_assert_internal(mi_block_ptr_is_guarded(block, p));
mi_assert_internal(mi_page_has_aligned(page));
mi_assert_internal((uint8_t*)p - (uint8_t*)block >= sizeof(mi_block_t));
mi_assert_internal(block->next == MI_BLOCK_TAG_GUARDED);
const size_t bsize = mi_page_block_size(page);
const size_t psize = _mi_os_page_size();
mi_assert_internal(bsize > psize);
mi_assert_internal(_mi_page_segment(page)->allow_decommit);
void* gpage = (uint8_t*)block + bsize - psize;
mi_assert_internal(_mi_is_aligned(gpage, psize));
_mi_os_unprotect(gpage, psize);
}
#endif