/* ---------------------------------------------------------------------------- Copyright (c) 2018, 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. -----------------------------------------------------------------------------*/ #pragma once #ifndef MIMALLOC_INTERNAL_H #define MIMALLOC_INTERNAL_H #include "mimalloc-types.h" #if defined(MI_MALLOC_OVERRIDE) #if defined(__APPLE__) #include #define MI_TLS_PTHREADS #elif (defined(__OpenBSD__) || defined(__DragonFly__)) #define MI_TLS_RECURSE_GUARD #endif #endif #if (MI_DEBUG>0) #define mi_trace_message(...) _mi_trace_message(__VA_ARGS__) #else #define mi_trace_message(...) #endif #define MI_CACHE_LINE 64 #if defined(_MSC_VER) #pragma warning(disable:4127) // suppress constant conditional warning (due to MI_SECURE paths) #define mi_decl_noinline __declspec(noinline) #define mi_decl_thread __declspec(thread) #define mi_decl_cache_align __declspec(align(MI_CACHE_LINE)) #elif (defined(__GNUC__) && (__GNUC__>=3)) // includes clang and icc #define mi_decl_noinline __attribute__((noinline)) #define mi_decl_thread __thread #define mi_decl_cache_align __attribute__((aligned(MI_CACHE_LINE))) #else #define mi_decl_noinline #define mi_decl_thread __thread // hope for the best :-) #define mi_decl_cache_align #endif // "options.c" void _mi_fputs(mi_output_fun* out, void* arg, const char* prefix, const char* message); void _mi_fprintf(mi_output_fun* out, void* arg, const char* fmt, ...); void _mi_warning_message(const char* fmt, ...); void _mi_verbose_message(const char* fmt, ...); void _mi_trace_message(const char* fmt, ...); void _mi_options_init(void); void _mi_error_message(int err, const char* fmt, ...); // random.c void _mi_random_init(mi_random_ctx_t* ctx); void _mi_random_split(mi_random_ctx_t* ctx, mi_random_ctx_t* new_ctx); uintptr_t _mi_random_next(mi_random_ctx_t* ctx); uintptr_t _mi_heap_random_next(mi_heap_t* heap); uintptr_t _os_random_weak(uintptr_t extra_seed); static inline uintptr_t _mi_random_shuffle(uintptr_t x); // init.c extern mi_stats_t _mi_stats_main; extern const mi_page_t _mi_page_empty; bool _mi_is_main_thread(void); bool _mi_preloading(); // true while the C runtime is not ready // os.c size_t _mi_os_page_size(void); void _mi_os_init(void); // called from process init void* _mi_os_alloc(size_t size, mi_stats_t* stats); // to allocate thread local data void _mi_os_free(void* p, size_t size, mi_stats_t* stats); // to free thread local data size_t _mi_os_good_alloc_size(size_t size); // memory.c void* _mi_mem_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* large, bool* is_zero, size_t* id, mi_os_tld_t* tld); void _mi_mem_free(void* p, size_t size, size_t id, bool fully_committed, bool any_reset, mi_os_tld_t* tld); bool _mi_mem_reset(void* p, size_t size, mi_os_tld_t* tld); bool _mi_mem_unreset(void* p, size_t size, bool* is_zero, mi_os_tld_t* tld); bool _mi_mem_commit(void* p, size_t size, bool* is_zero, mi_os_tld_t* tld); bool _mi_mem_protect(void* addr, size_t size); bool _mi_mem_unprotect(void* addr, size_t size); void _mi_mem_collect(mi_os_tld_t* tld); // "segment.c" mi_page_t* _mi_segment_page_alloc(mi_heap_t* heap, size_t block_wsize, mi_segments_tld_t* tld, mi_os_tld_t* os_tld); void _mi_segment_page_free(mi_page_t* page, bool force, mi_segments_tld_t* tld); void _mi_segment_page_abandon(mi_page_t* page, mi_segments_tld_t* tld); uint8_t* _mi_segment_page_start(const mi_segment_t* segment, const mi_page_t* page, size_t block_size, size_t* page_size, size_t* pre_size); // page start for any page void _mi_segment_huge_page_free(mi_segment_t* segment, mi_page_t* page, mi_block_t* block); void _mi_segment_thread_collect(mi_segments_tld_t* tld); void _mi_abandoned_reclaim_all(mi_heap_t* heap, mi_segments_tld_t* tld); void _mi_abandoned_await_readers(void); // "page.c" void* _mi_malloc_generic(mi_heap_t* heap, size_t size) mi_attr_noexcept mi_attr_malloc; void _mi_page_retire(mi_page_t* page); // free the page if there are no other pages with many free blocks void _mi_page_unfull(mi_page_t* page); void _mi_page_free(mi_page_t* page, mi_page_queue_t* pq, bool force); // free the page void _mi_page_abandon(mi_page_t* page, mi_page_queue_t* pq); // abandon the page, to be picked up by another thread... void _mi_heap_delayed_free(mi_heap_t* heap); void _mi_heap_collect_retired(mi_heap_t* heap, bool force); void _mi_page_use_delayed_free(mi_page_t* page, mi_delayed_t delay, bool override_never); size_t _mi_page_queue_append(mi_heap_t* heap, mi_page_queue_t* pq, mi_page_queue_t* append); void _mi_deferred_free(mi_heap_t* heap, bool force); void _mi_page_free_collect(mi_page_t* page,bool force); void _mi_page_reclaim(mi_heap_t* heap, mi_page_t* page); // callback from segments size_t _mi_bin_size(uint8_t bin); // for stats uint8_t _mi_bin(size_t size); // for stats uint8_t _mi_bsr(uintptr_t x); // bit-scan-right, used on BSD in "os.c" // "heap.c" void _mi_heap_destroy_pages(mi_heap_t* heap); void _mi_heap_collect_abandon(mi_heap_t* heap); void _mi_heap_set_default_direct(mi_heap_t* heap); // "stats.c" void _mi_stats_done(mi_stats_t* stats); mi_msecs_t _mi_clock_now(void); mi_msecs_t _mi_clock_end(mi_msecs_t start); mi_msecs_t _mi_clock_start(void); // "alloc.c" void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept; // called from `_mi_malloc_generic` void* _mi_heap_malloc_zero(mi_heap_t* heap, size_t size, bool zero); void* _mi_heap_realloc_zero(mi_heap_t* heap, void* p, size_t newsize, bool zero); mi_block_t* _mi_page_ptr_unalign(const mi_segment_t* segment, const mi_page_t* page, const void* p); bool _mi_free_delayed_block(mi_block_t* block); void _mi_block_zero_init(const mi_page_t* page, void* p, size_t size); #if MI_DEBUG>1 bool _mi_page_is_valid(mi_page_t* page); #endif // ------------------------------------------------------ // Branches // ------------------------------------------------------ #if defined(__GNUC__) || defined(__clang__) #define mi_unlikely(x) __builtin_expect((x),0) #define mi_likely(x) __builtin_expect((x),1) #else #define mi_unlikely(x) (x) #define mi_likely(x) (x) #endif #ifndef __has_builtin #define __has_builtin(x) 0 #endif /* ----------------------------------------------------------- Error codes passed to `_mi_fatal_error` All are recoverable but EFAULT is a serious error and aborts by default in secure mode. For portability define undefined error codes using common Unix codes: ----------------------------------------------------------- */ #include #ifndef EAGAIN // double free #define EAGAIN (11) #endif #ifndef ENOMEM // out of memory #define ENOMEM (12) #endif #ifndef EFAULT // corrupted free-list or meta-data #define EFAULT (14) #endif #ifndef EINVAL // trying to free an invalid pointer #define EINVAL (22) #endif #ifndef EOVERFLOW // count*size overflow #define EOVERFLOW (75) #endif /* ----------------------------------------------------------- Inlined definitions ----------------------------------------------------------- */ #define UNUSED(x) (void)(x) #if (MI_DEBUG>0) #define UNUSED_RELEASE(x) #else #define UNUSED_RELEASE(x) UNUSED(x) #endif #define MI_INIT4(x) x(),x(),x(),x() #define MI_INIT8(x) MI_INIT4(x),MI_INIT4(x) #define MI_INIT16(x) MI_INIT8(x),MI_INIT8(x) #define MI_INIT32(x) MI_INIT16(x),MI_INIT16(x) #define MI_INIT64(x) MI_INIT32(x),MI_INIT32(x) #define MI_INIT128(x) MI_INIT64(x),MI_INIT64(x) #define MI_INIT256(x) MI_INIT128(x),MI_INIT128(x) // Is `x` a power of two? (0 is considered a power of two) static inline bool _mi_is_power_of_two(uintptr_t x) { return ((x & (x - 1)) == 0); } // Align upwards static inline uintptr_t _mi_align_up(uintptr_t sz, size_t alignment) { mi_assert_internal(alignment != 0); uintptr_t mask = alignment - 1; if ((alignment & mask) == 0) { // power of two? return ((sz + mask) & ~mask); } else { return (((sz + mask)/alignment)*alignment); } } // Divide upwards: `s <= _mi_divide_up(s,d)*d < s+d`. static inline uintptr_t _mi_divide_up(uintptr_t size, size_t divider) { mi_assert_internal(divider != 0); return (divider == 0 ? size : ((size + divider - 1) / divider)); } // Is memory zero initialized? static inline bool mi_mem_is_zero(void* p, size_t size) { for (size_t i = 0; i < size; i++) { if (((uint8_t*)p)[i] != 0) return false; } return true; } // Align a byte size to a size in _machine words_, // i.e. byte size == `wsize*sizeof(void*)`. static inline size_t _mi_wsize_from_size(size_t size) { mi_assert_internal(size <= SIZE_MAX - sizeof(uintptr_t)); return (size + sizeof(uintptr_t) - 1) / sizeof(uintptr_t); } // Overflow detecting multiply static inline bool mi_mul_overflow(size_t count, size_t size, size_t* total) { #if __has_builtin(__builtin_umul_overflow) || __GNUC__ >= 5 #include // UINT_MAX, ULONG_MAX #if (SIZE_MAX == UINT_MAX) return __builtin_umul_overflow(count, size, total); #elif (SIZE_MAX == ULONG_MAX) return __builtin_umull_overflow(count, size, total); #else return __builtin_umulll_overflow(count, size, total); #endif #else /* __builtin_umul_overflow is unavailable */ #define MI_MUL_NO_OVERFLOW ((size_t)1 << (4*sizeof(size_t))) // sqrt(SIZE_MAX) *total = count * size; return ((size >= MI_MUL_NO_OVERFLOW || count >= MI_MUL_NO_OVERFLOW) && size > 0 && (SIZE_MAX / size) < count); #endif } // Safe multiply `count*size` into `total`; return `true` on overflow. static inline bool mi_count_size_overflow(size_t count, size_t size, size_t* total) { if (count==1) { // quick check for the case where count is one (common for C++ allocators) *total = size; return false; } else if (mi_unlikely(mi_mul_overflow(count, size, total))) { _mi_error_message(EOVERFLOW, "allocation request too large (%zu * %zu bytes)\n", count, size); *total = SIZE_MAX; return true; } else return false; } /* ----------------------------------------------------------- The thread local default heap ----------------------------------------------------------- */ extern const mi_heap_t _mi_heap_empty; // read-only empty heap, initial value of the thread local default heap extern mi_heap_t _mi_heap_main; // statically allocated main backing heap extern bool _mi_process_is_initialized; #if defined(MI_TLS_PTHREADS) extern pthread_key_t _mi_heap_default_key; #else extern mi_decl_thread mi_heap_t* _mi_heap_default; // default heap to allocate from #endif static inline mi_heap_t* mi_get_default_heap(void) { #if defined(MI_TLS_PTHREADS) // Use pthreads for TLS; this is used on macOSX with interpose as the loader calls `malloc` // to allocate TLS storage leading to recursive calls if __thread declared variables are accessed. // Using pthreads allows us to initialize without recursive calls. (performance seems still quite good). mi_heap_t* heap = (mi_unlikely(_mi_heap_default_key == (pthread_key_t)(-1)) ? (mi_heap_t*)&_mi_heap_empty : (mi_heap_t*)pthread_getspecific(_mi_heap_default_key)); return (mi_unlikely(heap == NULL) ? (mi_heap_t*)&_mi_heap_empty : heap); #else #if defined(MI_TLS_RECURSE_GUARD) // On some BSD platforms, like openBSD, the dynamic loader calls `malloc` // to initialize thread local data. To avoid recursion, we need to avoid // accessing the thread local `_mi_default_heap` until our module is loaded // and use the statically allocated main heap until that time. // TODO: patch ourselves dynamically to avoid this check every time? if (mi_unlikely(!_mi_process_is_initialized)) return &_mi_heap_main; #endif return _mi_heap_default; #endif } static inline bool mi_heap_is_default(const mi_heap_t* heap) { return (heap == mi_get_default_heap()); } static inline bool mi_heap_is_backing(const mi_heap_t* heap) { return (heap->tld->heap_backing == heap); } static inline bool mi_heap_is_initialized(mi_heap_t* heap) { mi_assert_internal(heap != NULL); return (heap != &_mi_heap_empty); } static inline uintptr_t _mi_ptr_cookie(const void* p) { mi_assert_internal(_mi_heap_main.cookie != 0); return ((uintptr_t)p ^ _mi_heap_main.cookie); } /* ----------------------------------------------------------- Pages ----------------------------------------------------------- */ static inline mi_page_t* _mi_heap_get_free_small_page(mi_heap_t* heap, size_t size) { mi_assert_internal(size <= (MI_SMALL_SIZE_MAX + MI_PADDING_SIZE)); const size_t idx = _mi_wsize_from_size(size); mi_assert_internal(idx < MI_PAGES_DIRECT); return heap->pages_free_direct[idx]; } // Get the page belonging to a certain size class static inline mi_page_t* _mi_get_free_small_page(size_t size) { return _mi_heap_get_free_small_page(mi_get_default_heap(), size); } // Segment that contains the pointer static inline mi_segment_t* _mi_ptr_segment(const void* p) { // mi_assert_internal(p != NULL); return (mi_segment_t*)((uintptr_t)p & ~MI_SEGMENT_MASK); } // Segment belonging to a page static inline mi_segment_t* _mi_page_segment(const mi_page_t* page) { mi_segment_t* segment = _mi_ptr_segment(page); mi_assert_internal(segment == NULL || page == &segment->pages[page->segment_idx]); return segment; } // used internally static inline uintptr_t _mi_segment_page_idx_of(const mi_segment_t* segment, const void* p) { // if (segment->page_size > MI_SEGMENT_SIZE) return &segment->pages[0]; // huge pages ptrdiff_t diff = (uint8_t*)p - (uint8_t*)segment; mi_assert_internal(diff >= 0 && (size_t)diff < MI_SEGMENT_SIZE); uintptr_t idx = (uintptr_t)diff >> segment->page_shift; mi_assert_internal(idx < segment->capacity); mi_assert_internal(segment->page_kind <= MI_PAGE_MEDIUM || idx == 0); return idx; } // Get the page containing the pointer static inline mi_page_t* _mi_segment_page_of(const mi_segment_t* segment, const void* p) { uintptr_t idx = _mi_segment_page_idx_of(segment, p); return &((mi_segment_t*)segment)->pages[idx]; } // Quick page start for initialized pages static inline uint8_t* _mi_page_start(const mi_segment_t* segment, const mi_page_t* page, size_t* page_size) { const size_t bsize = page->xblock_size; mi_assert_internal(bsize > 0 && (bsize%sizeof(void*)) == 0); return _mi_segment_page_start(segment, page, bsize, page_size, NULL); } // Get the page containing the pointer static inline mi_page_t* _mi_ptr_page(void* p) { return _mi_segment_page_of(_mi_ptr_segment(p), p); } // Get the block size of a page (special cased for huge objects) static inline size_t mi_page_block_size(const mi_page_t* page) { const size_t bsize = page->xblock_size; mi_assert_internal(bsize > 0); if (mi_likely(bsize < MI_HUGE_BLOCK_SIZE)) { return bsize; } else { size_t psize; _mi_segment_page_start(_mi_page_segment(page), page, bsize, &psize, NULL); return psize; } } // Get the usable block size of a page without fixed padding. // This may still include internal padding due to alignment and rounding up size classes. static inline size_t mi_page_usable_block_size(const mi_page_t* page) { return mi_page_block_size(page) - MI_PADDING_SIZE; } // Thread free access static inline mi_block_t* mi_page_thread_free(const mi_page_t* page) { return (mi_block_t*)(mi_atomic_read_relaxed(&page->xthread_free) & ~3); } static inline mi_delayed_t mi_page_thread_free_flag(const mi_page_t* page) { return (mi_delayed_t)(mi_atomic_read_relaxed(&page->xthread_free) & 3); } // Heap access static inline mi_heap_t* mi_page_heap(const mi_page_t* page) { return (mi_heap_t*)(mi_atomic_read_relaxed(&page->xheap)); } static inline void mi_page_set_heap(mi_page_t* page, mi_heap_t* heap) { mi_assert_internal(mi_page_thread_free_flag(page) != MI_DELAYED_FREEING); mi_atomic_write(&page->xheap,(uintptr_t)heap); } // Thread free flag helpers static inline mi_block_t* mi_tf_block(mi_thread_free_t tf) { return (mi_block_t*)(tf & ~0x03); } static inline mi_delayed_t mi_tf_delayed(mi_thread_free_t tf) { return (mi_delayed_t)(tf & 0x03); } static inline mi_thread_free_t mi_tf_make(mi_block_t* block, mi_delayed_t delayed) { return (mi_thread_free_t)((uintptr_t)block | (uintptr_t)delayed); } static inline mi_thread_free_t mi_tf_set_delayed(mi_thread_free_t tf, mi_delayed_t delayed) { return mi_tf_make(mi_tf_block(tf),delayed); } static inline mi_thread_free_t mi_tf_set_block(mi_thread_free_t tf, mi_block_t* block) { return mi_tf_make(block, mi_tf_delayed(tf)); } // are all blocks in a page freed? // note: needs up-to-date used count, (as the `xthread_free` list may not be empty). see `_mi_page_collect_free`. static inline bool mi_page_all_free(const mi_page_t* page) { mi_assert_internal(page != NULL); return (page->used == 0); } // are there any available blocks? static inline bool mi_page_has_any_available(const mi_page_t* page) { mi_assert_internal(page != NULL && page->reserved > 0); return (page->used < page->reserved || (mi_page_thread_free(page) != NULL)); } // are there immediately available blocks, i.e. blocks available on the free list. static inline bool mi_page_immediate_available(const mi_page_t* page) { mi_assert_internal(page != NULL); return (page->free != NULL); } // is more than 7/8th of a page in use? static inline bool mi_page_mostly_used(const mi_page_t* page) { if (page==NULL) return true; uint16_t frac = page->reserved / 8U; return (page->reserved - page->used <= frac); } static inline mi_page_queue_t* mi_page_queue(const mi_heap_t* heap, size_t size) { return &((mi_heap_t*)heap)->pages[_mi_bin(size)]; } //----------------------------------------------------------- // Page flags //----------------------------------------------------------- static inline bool mi_page_is_in_full(const mi_page_t* page) { return page->flags.x.in_full; } static inline void mi_page_set_in_full(mi_page_t* page, bool in_full) { page->flags.x.in_full = in_full; } static inline bool mi_page_has_aligned(const mi_page_t* page) { return page->flags.x.has_aligned; } static inline void mi_page_set_has_aligned(mi_page_t* page, bool has_aligned) { page->flags.x.has_aligned = has_aligned; } /* ------------------------------------------------------------------- Encoding/Decoding the free list next pointers This is to protect against buffer overflow exploits where the free list is mutated. Many hardened allocators xor the next pointer `p` with a secret key `k1`, as `p^k1`. This prevents overwriting with known values but might be still too weak: if the attacker can guess the pointer `p` this can reveal `k1` (since `p^k1^p == k1`). Moreover, if multiple blocks can be read as well, the attacker can xor both as `(p1^k1) ^ (p2^k1) == p1^p2` which may reveal a lot about the pointers (and subsequently `k1`). Instead mimalloc uses an extra key `k2` and encodes as `((p^k2)<<> (MI_INTPTR_BITS - shift))); } static inline uintptr_t mi_rotr(uintptr_t x, uintptr_t shift) { shift %= MI_INTPTR_BITS; return ((x >> shift) | (x << (MI_INTPTR_BITS - shift))); } static inline void* mi_ptr_decode(const void* null, const mi_encoded_t x, const uintptr_t* keys) { void* p = (void*)(mi_rotr(x - keys[0], keys[0]) ^ keys[1]); return (mi_unlikely(p==null) ? NULL : p); } static inline mi_encoded_t mi_ptr_encode(const void* null, const void* p, const uintptr_t* keys) { uintptr_t x = (uintptr_t)(mi_unlikely(p==NULL) ? null : p); return mi_rotl(x ^ keys[1], keys[0]) + keys[0]; } static inline mi_block_t* mi_block_nextx( const void* null, const mi_block_t* block, const uintptr_t* keys ) { #ifdef MI_ENCODE_FREELIST return (mi_block_t*)mi_ptr_decode(null, block->next, keys); #else UNUSED(keys); UNUSED(null); return (mi_block_t*)block->next; #endif } static inline void mi_block_set_nextx(const void* null, mi_block_t* block, const mi_block_t* next, const uintptr_t* keys) { #ifdef MI_ENCODE_FREELIST block->next = mi_ptr_encode(null, next, keys); #else UNUSED(keys); UNUSED(null); block->next = (mi_encoded_t)next; #endif } static inline mi_block_t* mi_block_next(const mi_page_t* page, const mi_block_t* block) { #ifdef MI_ENCODE_FREELIST mi_block_t* next = mi_block_nextx(page,block,page->keys); // check for free list corruption: is `next` at least in the same page? // TODO: check if `next` is `page->block_size` aligned? if (mi_unlikely(next!=NULL && !mi_is_in_same_page(block, next))) { _mi_error_message(EFAULT, "corrupted free list entry of size %zub at %p: value 0x%zx\n", mi_page_block_size(page), block, (uintptr_t)next); next = NULL; } return next; #else UNUSED(page); return mi_block_nextx(page,block,NULL); #endif } static inline void mi_block_set_next(const mi_page_t* page, mi_block_t* block, const mi_block_t* next) { #ifdef MI_ENCODE_FREELIST mi_block_set_nextx(page,block,next, page->keys); #else UNUSED(page); mi_block_set_nextx(page,block,next,NULL); #endif } // ------------------------------------------------------------------- // Fast "random" shuffle // ------------------------------------------------------------------- static inline uintptr_t _mi_random_shuffle(uintptr_t x) { if (x==0) { x = 17; } // ensure we don't get stuck in generating zeros #if (MI_INTPTR_SIZE==8) // by Sebastiano Vigna, see: x ^= x >> 30; x *= 0xbf58476d1ce4e5b9UL; x ^= x >> 27; x *= 0x94d049bb133111ebUL; x ^= x >> 31; #elif (MI_INTPTR_SIZE==4) // by Chris Wellons, see: x ^= x >> 16; x *= 0x7feb352dUL; x ^= x >> 15; x *= 0x846ca68bUL; x ^= x >> 16; #endif return x; } // ------------------------------------------------------------------- // Optimize numa node access for the common case (= one node) // ------------------------------------------------------------------- int _mi_os_numa_node_get(mi_os_tld_t* tld); size_t _mi_os_numa_node_count_get(void); extern size_t _mi_numa_node_count; static inline int _mi_os_numa_node(mi_os_tld_t* tld) { if (mi_likely(_mi_numa_node_count == 1)) return 0; else return _mi_os_numa_node_get(tld); } static inline size_t _mi_os_numa_node_count(void) { if (mi_likely(_mi_numa_node_count>0)) return _mi_numa_node_count; else return _mi_os_numa_node_count_get(); } // ------------------------------------------------------------------- // Getting the thread id should be performant // as it is called in the fast path of `_mi_free`, // so we specialize for various platforms. // ------------------------------------------------------------------- #if defined(_WIN32) #define WIN32_LEAN_AND_MEAN #include static inline uintptr_t _mi_thread_id(void) mi_attr_noexcept { // Windows: works on Intel and ARM in both 32- and 64-bit return (uintptr_t)NtCurrentTeb(); } #elif (defined(__GNUC__) || defined(__clang__)) && \ (defined(__x86_64__) || defined(__i386__) || defined(__arm__) || defined(__aarch64__)) // TLS register on x86 is in the FS or GS register // see: https://akkadia.org/drepper/tls.pdf static inline uintptr_t _mi_thread_id(void) mi_attr_noexcept { uintptr_t tid; #if defined(__i386__) __asm__("movl %%gs:0, %0" : "=r" (tid) : : ); // 32-bit always uses GS #elif defined(__MACH__) __asm__("movq %%gs:0, %0" : "=r" (tid) : : ); // x86_64 macOS uses GS #elif defined(__x86_64__) __asm__("movq %%fs:0, %0" : "=r" (tid) : : ); // x86_64 Linux, BSD uses FS #elif defined(__arm__) asm volatile ("mrc p15, 0, %0, c13, c0, 3" : "=r" (tid)); #elif defined(__aarch64__) asm volatile ("mrs %0, tpidr_el0" : "=r" (tid)); #endif return tid; } #else // otherwise use standard C static inline uintptr_t _mi_thread_id(void) mi_attr_noexcept { return (uintptr_t)&_mi_heap_default; } #endif #endif