/* ---------------------------------------------------------------------------- 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. -----------------------------------------------------------------------------*/ #include "mimalloc.h" #include "mimalloc/internal.h" #include "mimalloc/prim.h" #include // memcpy, memset #include // atexit // Empty page used to initialize the small free pages array const mi_page_t _mi_page_empty = { 0, false, false, false, 0, 0, // capacity 0, // reserved capacity { 0 }, // flags false, // is_zero 0, // retire_expire NULL, // free 0, // used 0, // xblock_size NULL, // local_free #if (MI_PADDING || MI_ENCODE_FREELIST) { 0, 0 }, #endif MI_ATOMIC_VAR_INIT(0), // xthread_free MI_ATOMIC_VAR_INIT(0), // xheap NULL, NULL #if MI_INTPTR_SIZE==8 , { 0 } // padding #endif }; #define MI_PAGE_EMPTY() ((mi_page_t*)&_mi_page_empty) #if (MI_SMALL_WSIZE_MAX==128) #if (MI_PADDING>0) && (MI_INTPTR_SIZE >= 8) #define MI_SMALL_PAGES_EMPTY { MI_INIT128(MI_PAGE_EMPTY), MI_PAGE_EMPTY(), MI_PAGE_EMPTY() } #elif (MI_PADDING>0) #define MI_SMALL_PAGES_EMPTY { MI_INIT128(MI_PAGE_EMPTY), MI_PAGE_EMPTY(), MI_PAGE_EMPTY(), MI_PAGE_EMPTY() } #else #define MI_SMALL_PAGES_EMPTY { MI_INIT128(MI_PAGE_EMPTY), MI_PAGE_EMPTY() } #endif #else #error "define right initialization sizes corresponding to MI_SMALL_WSIZE_MAX" #endif // Empty page queues for every bin #define QNULL(sz) { NULL, NULL, (sz)*sizeof(uintptr_t) } #define MI_PAGE_QUEUES_EMPTY \ { QNULL(1), \ QNULL( 1), QNULL( 2), QNULL( 3), QNULL( 4), QNULL( 5), QNULL( 6), QNULL( 7), QNULL( 8), /* 8 */ \ QNULL( 10), QNULL( 12), QNULL( 14), QNULL( 16), QNULL( 20), QNULL( 24), QNULL( 28), QNULL( 32), /* 16 */ \ QNULL( 40), QNULL( 48), QNULL( 56), QNULL( 64), QNULL( 80), QNULL( 96), QNULL( 112), QNULL( 128), /* 24 */ \ QNULL( 160), QNULL( 192), QNULL( 224), QNULL( 256), QNULL( 320), QNULL( 384), QNULL( 448), QNULL( 512), /* 32 */ \ QNULL( 640), QNULL( 768), QNULL( 896), QNULL( 1024), QNULL( 1280), QNULL( 1536), QNULL( 1792), QNULL( 2048), /* 40 */ \ QNULL( 2560), QNULL( 3072), QNULL( 3584), QNULL( 4096), QNULL( 5120), QNULL( 6144), QNULL( 7168), QNULL( 8192), /* 48 */ \ QNULL( 10240), QNULL( 12288), QNULL( 14336), QNULL( 16384), QNULL( 20480), QNULL( 24576), QNULL( 28672), QNULL( 32768), /* 56 */ \ QNULL( 40960), QNULL( 49152), QNULL( 57344), QNULL( 65536), QNULL( 81920), QNULL( 98304), QNULL(114688), QNULL(131072), /* 64 */ \ QNULL(163840), QNULL(196608), QNULL(229376), QNULL(262144), QNULL(327680), QNULL(393216), QNULL(458752), QNULL(524288), /* 72 */ \ QNULL(MI_MEDIUM_OBJ_WSIZE_MAX + 1 /* 655360, Huge queue */), \ QNULL(MI_MEDIUM_OBJ_WSIZE_MAX + 2) /* Full queue */ } #define MI_STAT_COUNT_NULL() {0,0,0,0} // Empty statistics #if MI_STAT>1 #define MI_STAT_COUNT_END_NULL() , { MI_STAT_COUNT_NULL(), MI_INIT32(MI_STAT_COUNT_NULL) } #else #define MI_STAT_COUNT_END_NULL() #endif #define MI_STATS_NULL \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \ MI_STAT_COUNT_NULL(), \ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, \ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } \ MI_STAT_COUNT_END_NULL() // Empty slice span queues for every bin #define SQNULL(sz) { NULL, NULL, sz } #define MI_SEGMENT_SPAN_QUEUES_EMPTY \ { SQNULL(1), \ SQNULL( 1), SQNULL( 2), SQNULL( 3), SQNULL( 4), SQNULL( 5), SQNULL( 6), SQNULL( 7), SQNULL( 10), /* 8 */ \ SQNULL( 12), SQNULL( 14), SQNULL( 16), SQNULL( 20), SQNULL( 24), SQNULL( 28), SQNULL( 32), SQNULL( 40), /* 16 */ \ SQNULL( 48), SQNULL( 56), SQNULL( 64), SQNULL( 80), SQNULL( 96), SQNULL( 112), SQNULL( 128), SQNULL( 160), /* 24 */ \ SQNULL( 192), SQNULL( 224), SQNULL( 256), SQNULL( 320), SQNULL( 384), SQNULL( 448), SQNULL( 512), SQNULL( 640), /* 32 */ \ SQNULL( 768), SQNULL( 896), SQNULL( 1024) /* 35 */ } // -------------------------------------------------------- // Statically allocate an empty heap as the initial // thread local value for the default heap, // and statically allocate the backing heap for the main // thread so it can function without doing any allocation // itself (as accessing a thread local for the first time // may lead to allocation itself on some platforms) // -------------------------------------------------------- mi_decl_cache_align const mi_heap_t _mi_heap_empty = { NULL, MI_SMALL_PAGES_EMPTY, MI_PAGE_QUEUES_EMPTY, MI_ATOMIC_VAR_INIT(NULL), 0, // tid 0, // cookie 0, // arena id { 0, 0 }, // keys { {0}, {0}, 0, true }, // random 0, // page count MI_BIN_FULL, 0, // page retired min/max NULL, // next false, 0 }; #define tld_empty_stats ((mi_stats_t*)((uint8_t*)&tld_empty + offsetof(mi_tld_t,stats))) #define tld_empty_os ((mi_os_tld_t*)((uint8_t*)&tld_empty + offsetof(mi_tld_t,os))) mi_decl_cache_align static const mi_tld_t tld_empty = { 0, false, NULL, NULL, { MI_SEGMENT_SPAN_QUEUES_EMPTY, 0, 0, 0, 0, tld_empty_stats, tld_empty_os, &_mi_abandoned_default }, // segments { 0, tld_empty_stats }, // os { MI_STATS_NULL } // stats }; mi_threadid_t _mi_thread_id(void) mi_attr_noexcept { return _mi_prim_thread_id(); } // the thread-local default heap for allocation mi_decl_thread mi_heap_t* _mi_heap_default = (mi_heap_t*)&_mi_heap_empty; extern mi_heap_t _mi_heap_main; static mi_tld_t tld_main = { 0, false, &_mi_heap_main, & _mi_heap_main, { MI_SEGMENT_SPAN_QUEUES_EMPTY, 0, 0, 0, 0, &tld_main.stats, &tld_main.os, &_mi_abandoned_default }, // segments { 0, &tld_main.stats }, // os { MI_STATS_NULL } // stats }; mi_heap_t _mi_heap_main = { &tld_main, MI_SMALL_PAGES_EMPTY, MI_PAGE_QUEUES_EMPTY, MI_ATOMIC_VAR_INIT(NULL), 0, // thread id 0, // initial cookie 0, // arena id { 0, 0 }, // the key of the main heap can be fixed (unlike page keys that need to be secure!) { {0x846ca68b}, {0}, 0, true }, // random 0, // page count MI_BIN_FULL, 0, // page retired min/max NULL, // next heap false // can reclaim }; bool _mi_process_is_initialized = false; // set to `true` in `mi_process_init`. mi_stats_t _mi_stats_main = { MI_STATS_NULL }; static void mi_heap_main_init(void) { if (_mi_heap_main.cookie == 0) { _mi_heap_main.thread_id = _mi_thread_id(); _mi_heap_main.cookie = 1; #if defined(_WIN32) && !defined(MI_SHARED_LIB) _mi_random_init_weak(&_mi_heap_main.random); // prevent allocation failure during bcrypt dll initialization with static linking #else _mi_random_init(&_mi_heap_main.random); #endif _mi_heap_main.cookie = _mi_heap_random_next(&_mi_heap_main); _mi_heap_main.keys[0] = _mi_heap_random_next(&_mi_heap_main); _mi_heap_main.keys[1] = _mi_heap_random_next(&_mi_heap_main); } } mi_heap_t* _mi_heap_main_get(void) { mi_heap_main_init(); return &_mi_heap_main; } /* ----------------------------------------------------------- Initialization and freeing of the thread local heaps ----------------------------------------------------------- */ // note: in x64 in release build `sizeof(mi_thread_data_t)` is under 4KiB (= OS page size). typedef struct mi_thread_data_s { mi_heap_t heap; // must come first due to cast in `_mi_heap_done` mi_tld_t tld; mi_memid_t memid; } mi_thread_data_t; // Thread meta-data is allocated directly from the OS. For // some programs that do not use thread pools and allocate and // destroy many OS threads, this may causes too much overhead // per thread so we maintain a small cache of recently freed metadata. #define TD_CACHE_SIZE (16) static _Atomic(mi_thread_data_t*) td_cache[TD_CACHE_SIZE]; static mi_thread_data_t* mi_thread_data_zalloc(void) { // try to find thread metadata in the cache bool is_zero = false; mi_thread_data_t* td = NULL; for (int i = 0; i < TD_CACHE_SIZE; i++) { td = mi_atomic_load_ptr_relaxed(mi_thread_data_t, &td_cache[i]); if (td != NULL) { // found cached allocation, try use it td = mi_atomic_exchange_ptr_acq_rel(mi_thread_data_t, &td_cache[i], NULL); if (td != NULL) { break; } } } // if that fails, allocate as meta data if (td == NULL) { mi_memid_t memid; td = (mi_thread_data_t*)_mi_os_alloc(sizeof(mi_thread_data_t), &memid, &_mi_stats_main); if (td == NULL) { // if this fails, try once more. (issue #257) td = (mi_thread_data_t*)_mi_os_alloc(sizeof(mi_thread_data_t), &memid, &_mi_stats_main); if (td == NULL) { // really out of memory _mi_error_message(ENOMEM, "unable to allocate thread local heap metadata (%zu bytes)\n", sizeof(mi_thread_data_t)); } } if (td != NULL) { td->memid = memid; is_zero = memid.initially_zero; } } if (td != NULL && !is_zero) { _mi_memzero_aligned(td, sizeof(*td)); } return td; } static void mi_thread_data_free( mi_thread_data_t* tdfree ) { // try to add the thread metadata to the cache for (int i = 0; i < TD_CACHE_SIZE; i++) { mi_thread_data_t* td = mi_atomic_load_ptr_relaxed(mi_thread_data_t, &td_cache[i]); if (td == NULL) { mi_thread_data_t* expected = NULL; if (mi_atomic_cas_ptr_weak_acq_rel(mi_thread_data_t, &td_cache[i], &expected, tdfree)) { return; } } } // if that fails, just free it directly _mi_os_free(tdfree, sizeof(mi_thread_data_t), tdfree->memid, &_mi_stats_main); } void _mi_thread_data_collect(void) { // free all thread metadata from the cache for (int i = 0; i < TD_CACHE_SIZE; i++) { mi_thread_data_t* td = mi_atomic_load_ptr_relaxed(mi_thread_data_t, &td_cache[i]); if (td != NULL) { td = mi_atomic_exchange_ptr_acq_rel(mi_thread_data_t, &td_cache[i], NULL); if (td != NULL) { _mi_os_free(td, sizeof(mi_thread_data_t), td->memid, &_mi_stats_main); } } } } // Initialize the thread local default heap, called from `mi_thread_init` static bool _mi_heap_init(void) { if (mi_heap_is_initialized(mi_prim_get_default_heap())) return true; if (_mi_is_main_thread()) { // mi_assert_internal(_mi_heap_main.thread_id != 0); // can happen on freeBSD where alloc is called before any initialization // the main heap is statically allocated mi_heap_main_init(); _mi_heap_set_default_direct(&_mi_heap_main); //mi_assert_internal(_mi_heap_default->tld->heap_backing == mi_prim_get_default_heap()); } else { // use `_mi_os_alloc` to allocate directly from the OS mi_thread_data_t* td = mi_thread_data_zalloc(); if (td == NULL) return false; _mi_tld_init(&td->tld, &td->heap); _mi_heap_init_ex(&td->heap, &td->tld, _mi_arena_id_none(), false, 0); _mi_heap_set_default_direct(&td->heap); } return false; } void _mi_tld_init(mi_tld_t* tld, mi_heap_t* bheap) { _mi_memcpy_aligned(tld, &tld_empty, sizeof(*tld)); tld->segments.stats = &tld->stats; tld->segments.os = &tld->os; tld->segments.abandoned = &_mi_abandoned_default; tld->os.stats = &tld->stats; tld->heap_backing = bheap; } // Free the thread local default heap (called from `mi_thread_done`) static bool _mi_heap_done(mi_heap_t* heap) { if (!mi_heap_is_initialized(heap)) return true; // reset default heap _mi_heap_set_default_direct(_mi_is_main_thread() ? &_mi_heap_main : (mi_heap_t*)&_mi_heap_empty); // switch to backing heap heap = heap->tld->heap_backing; if (!mi_heap_is_initialized(heap)) return false; // delete all non-backing heaps in this thread mi_heap_t* curr = heap->tld->heaps; while (curr != NULL) { mi_heap_t* next = curr->next; // save `next` as `curr` will be freed if (curr != heap) { mi_assert_internal(!mi_heap_is_backing(curr)); mi_heap_delete(curr); } curr = next; } mi_assert_internal(heap->tld->heaps == heap && heap->next == NULL); mi_assert_internal(mi_heap_is_backing(heap)); // collect if not the main thread if (heap != &_mi_heap_main) { _mi_heap_collect_abandon(heap); } // merge stats _mi_stats_done(&heap->tld->stats); // free if not the main thread if (heap != &_mi_heap_main) { // the following assertion does not always hold for huge segments as those are always treated // as abondened: one may allocate it in one thread, but deallocate in another in which case // the count can be too large or negative. todo: perhaps not count huge segments? see issue #363 // mi_assert_internal(heap->tld->segments.count == 0 || heap->thread_id != _mi_thread_id()); mi_thread_data_free((mi_thread_data_t*)heap); } else { #if 0 // never free the main thread even in debug mode; if a dll is linked statically with mimalloc, // there may still be delete/free calls after the mi_fls_done is called. Issue #207 _mi_heap_destroy_pages(heap); mi_assert_internal(heap->tld->heap_backing == &_mi_heap_main); #endif } return false; } // -------------------------------------------------------- // Try to run `mi_thread_done()` automatically so any memory // owned by the thread but not yet released can be abandoned // and re-owned by another thread. // // 1. windows dynamic library: // call from DllMain on DLL_THREAD_DETACH // 2. windows static library: // use `FlsAlloc` to call a destructor when the thread is done // 3. unix, pthreads: // use a pthread key to call a destructor when a pthread is done // // In the last two cases we also need to call `mi_process_init` // to set up the thread local keys. // -------------------------------------------------------- // Set up handlers so `mi_thread_done` is called automatically static void mi_process_setup_auto_thread_done(void) { static bool tls_initialized = false; // fine if it races if (tls_initialized) return; tls_initialized = true; _mi_prim_thread_init_auto_done(); _mi_heap_set_default_direct(&_mi_heap_main); } bool _mi_is_main_thread(void) { return (_mi_heap_main.thread_id==0 || _mi_heap_main.thread_id == _mi_thread_id()); } static _Atomic(size_t) thread_count = MI_ATOMIC_VAR_INIT(1); size_t _mi_current_thread_count(void) { return mi_atomic_load_relaxed(&thread_count); } // This is called from the `mi_malloc_generic` void mi_thread_init(void) mi_attr_noexcept { // ensure our process has started already mi_process_init(); // initialize the thread local default heap // (this will call `_mi_heap_set_default_direct` and thus set the // fiber/pthread key to a non-zero value, ensuring `_mi_thread_done` is called) if (_mi_heap_init()) return; // returns true if already initialized _mi_stat_increase(&_mi_stats_main.threads, 1); mi_atomic_increment_relaxed(&thread_count); //_mi_verbose_message("thread init: 0x%zx\n", _mi_thread_id()); } void mi_thread_done(void) mi_attr_noexcept { _mi_thread_done(NULL); } void _mi_thread_done(mi_heap_t* heap) { // calling with NULL implies using the default heap if (heap == NULL) { heap = mi_prim_get_default_heap(); if (heap == NULL) return; } // prevent re-entrancy through heap_done/heap_set_default_direct (issue #699) if (!mi_heap_is_initialized(heap)) { return; } // adjust stats mi_atomic_decrement_relaxed(&thread_count); _mi_stat_decrease(&_mi_stats_main.threads, 1); // check thread-id as on Windows shutdown with FLS the main (exit) thread may call this on thread-local heaps... if (heap->thread_id != _mi_thread_id()) return; // abandon the thread local heap if (_mi_heap_done(heap)) return; // returns true if already ran } void _mi_heap_set_default_direct(mi_heap_t* heap) { mi_assert_internal(heap != NULL); #if defined(MI_TLS_SLOT) mi_prim_tls_slot_set(MI_TLS_SLOT,heap); #elif defined(MI_TLS_PTHREAD_SLOT_OFS) *mi_tls_pthread_heap_slot() = heap; #elif defined(MI_TLS_PTHREAD) // we use _mi_heap_default_key #else _mi_heap_default = heap; #endif // ensure the default heap is passed to `_mi_thread_done` // setting to a non-NULL value also ensures `mi_thread_done` is called. _mi_prim_thread_associate_default_heap(heap); } // -------------------------------------------------------- // Run functions on process init/done, and thread init/done // -------------------------------------------------------- static void mi_cdecl mi_process_done(void); static bool os_preloading = true; // true until this module is initialized static bool mi_redirected = false; // true if malloc redirects to mi_malloc // Returns true if this module has not been initialized; Don't use C runtime routines until it returns false. bool mi_decl_noinline _mi_preloading(void) { return os_preloading; } mi_decl_nodiscard bool mi_is_redirected(void) mi_attr_noexcept { return mi_redirected; } // Communicate with the redirection module on Windows #if defined(_WIN32) && defined(MI_SHARED_LIB) && !defined(MI_WIN_NOREDIRECT) #ifdef __cplusplus extern "C" { #endif mi_decl_export void _mi_redirect_entry(DWORD reason) { // called on redirection; careful as this may be called before DllMain if (reason == DLL_PROCESS_ATTACH) { mi_redirected = true; } else if (reason == DLL_PROCESS_DETACH) { mi_redirected = false; } else if (reason == DLL_THREAD_DETACH) { mi_thread_done(); } } __declspec(dllimport) bool mi_cdecl mi_allocator_init(const char** message); __declspec(dllimport) void mi_cdecl mi_allocator_done(void); #ifdef __cplusplus } #endif #else static bool mi_allocator_init(const char** message) { if (message != NULL) *message = NULL; return true; } static void mi_allocator_done(void) { // nothing to do } #endif // Called once by the process loader static void mi_process_load(void) { mi_heap_main_init(); #if defined(__APPLE__) || defined(MI_TLS_RECURSE_GUARD) volatile mi_heap_t* dummy = _mi_heap_default; // access TLS to allocate it before setting tls_initialized to true; if (dummy == NULL) return; // use dummy or otherwise the access may get optimized away (issue #697) #endif os_preloading = false; mi_assert_internal(_mi_is_main_thread()); #if !(defined(_WIN32) && defined(MI_SHARED_LIB)) // use Dll process detach (see below) instead of atexit (issue #521) atexit(&mi_process_done); #endif _mi_options_init(); mi_process_setup_auto_thread_done(); mi_process_init(); if (mi_redirected) _mi_verbose_message("malloc is redirected.\n"); // show message from the redirector (if present) const char* msg = NULL; mi_allocator_init(&msg); if (msg != NULL && (mi_option_is_enabled(mi_option_verbose) || mi_option_is_enabled(mi_option_show_errors))) { _mi_fputs(NULL,NULL,NULL,msg); } // reseed random _mi_random_reinit_if_weak(&_mi_heap_main.random); } #if defined(_WIN32) && (defined(_M_IX86) || defined(_M_X64)) #include mi_decl_cache_align bool _mi_cpu_has_fsrm = false; static void mi_detect_cpu_features(void) { // FSRM for fast rep movsb support (AMD Zen3+ (~2020) or Intel Ice Lake+ (~2017)) int32_t cpu_info[4]; __cpuid(cpu_info, 7); _mi_cpu_has_fsrm = ((cpu_info[3] & (1 << 4)) != 0); // bit 4 of EDX : see } #else static void mi_detect_cpu_features(void) { // nothing } #endif // Initialize the process; called by thread_init or the process loader void mi_process_init(void) mi_attr_noexcept { // ensure we are called once static mi_atomic_once_t process_init; #if _MSC_VER < 1920 mi_heap_main_init(); // vs2017 can dynamically re-initialize _mi_heap_main #endif if (!mi_atomic_once(&process_init)) return; _mi_process_is_initialized = true; _mi_verbose_message("process init: 0x%zx\n", _mi_thread_id()); mi_process_setup_auto_thread_done(); mi_detect_cpu_features(); _mi_os_init(); mi_heap_main_init(); #if MI_DEBUG _mi_verbose_message("debug level : %d\n", MI_DEBUG); #endif _mi_verbose_message("secure level: %d\n", MI_SECURE); _mi_verbose_message("mem tracking: %s\n", MI_TRACK_TOOL); #if MI_TSAN _mi_verbose_message("thread santizer enabled\n"); #endif mi_thread_init(); #if defined(_WIN32) // On windows, when building as a static lib the FLS cleanup happens to early for the main thread. // To avoid this, set the FLS value for the main thread to NULL so the fls cleanup // will not call _mi_thread_done on the (still executing) main thread. See issue #508. _mi_prim_thread_associate_default_heap(NULL); #endif mi_stats_reset(); // only call stat reset *after* thread init (or the heap tld == NULL) mi_track_init(); if (mi_option_is_enabled(mi_option_reserve_huge_os_pages)) { size_t pages = mi_option_get_clamp(mi_option_reserve_huge_os_pages, 0, 128*1024); long reserve_at = mi_option_get(mi_option_reserve_huge_os_pages_at); if (reserve_at != -1) { mi_reserve_huge_os_pages_at(pages, reserve_at, pages*500); } else { mi_reserve_huge_os_pages_interleave(pages, 0, pages*500); } } if (mi_option_is_enabled(mi_option_reserve_os_memory)) { long ksize = mi_option_get(mi_option_reserve_os_memory); if (ksize > 0) { mi_reserve_os_memory((size_t)ksize*MI_KiB, true /* commit? */, true /* allow large pages? */); } } } // Called when the process is done (through `at_exit`) static void mi_cdecl mi_process_done(void) { // only shutdown if we were initialized if (!_mi_process_is_initialized) return; // ensure we are called once static bool process_done = false; if (process_done) return; process_done = true; // release any thread specific resources and ensure _mi_thread_done is called on all but the main thread _mi_prim_thread_done_auto_done(); #ifndef MI_SKIP_COLLECT_ON_EXIT #if (MI_DEBUG || !defined(MI_SHARED_LIB)) // free all memory if possible on process exit. This is not needed for a stand-alone process // but should be done if mimalloc is statically linked into another shared library which // is repeatedly loaded/unloaded, see issue #281. mi_collect(true /* force */ ); #endif #endif // Forcefully release all retained memory; this can be dangerous in general if overriding regular malloc/free // since after process_done there might still be other code running that calls `free` (like at_exit routines, // or C-runtime termination code. if (mi_option_is_enabled(mi_option_destroy_on_exit)) { mi_collect(true /* force */); _mi_heap_unsafe_destroy_all(); // forcefully release all memory held by all heaps (of this thread only!) _mi_arena_unsafe_destroy_all(& _mi_heap_main_get()->tld->stats); } if (mi_option_is_enabled(mi_option_show_stats) || mi_option_is_enabled(mi_option_verbose)) { mi_stats_print(NULL); } mi_allocator_done(); _mi_verbose_message("process done: 0x%zx\n", _mi_heap_main.thread_id); os_preloading = true; // don't call the C runtime anymore } #if defined(_WIN32) && defined(MI_SHARED_LIB) // Windows DLL: easy to hook into process_init and thread_done __declspec(dllexport) BOOL WINAPI DllMain(HINSTANCE inst, DWORD reason, LPVOID reserved) { MI_UNUSED(reserved); MI_UNUSED(inst); if (reason==DLL_PROCESS_ATTACH) { mi_process_load(); } else if (reason==DLL_PROCESS_DETACH) { mi_process_done(); } else if (reason==DLL_THREAD_DETACH) { if (!mi_is_redirected()) { mi_thread_done(); } } return TRUE; } #elif defined(_MSC_VER) // MSVC: use data section magic for static libraries // See static int _mi_process_init(void) { mi_process_load(); return 0; } typedef int(*_mi_crt_callback_t)(void); #if defined(_M_X64) || defined(_M_ARM64) __pragma(comment(linker, "/include:" "_mi_msvc_initu")) #pragma section(".CRT$XIU", long, read) #else __pragma(comment(linker, "/include:" "__mi_msvc_initu")) #endif #pragma data_seg(".CRT$XIU") mi_decl_externc _mi_crt_callback_t _mi_msvc_initu[] = { &_mi_process_init }; #pragma data_seg() #elif defined(__cplusplus) // C++: use static initialization to detect process start static bool _mi_process_init(void) { mi_process_load(); return (_mi_heap_main.thread_id != 0); } static bool mi_initialized = _mi_process_init(); #elif defined(__GNUC__) || defined(__clang__) // GCC,Clang: use the constructor attribute static void __attribute__((constructor)) _mi_process_init(void) { mi_process_load(); } #else #pragma message("define a way to call mi_process_load on your platform") #endif