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reorganize primitives for process initialization; use special data se…
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…gment on Windows for thread termination by default on Windows now (issue #869)
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@daanx
daanx committed Oct 22, 2024
1 parent 34e6677 commit aa88173
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Showing 4 changed files with 207 additions and 149 deletions.
5 changes: 5 additions & 0 deletions include/mimalloc/internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,11 @@ static inline uintptr_t _mi_random_shuffle(uintptr_t x);
// init.c
extern mi_decl_cache_align mi_stats_t _mi_stats_main;
extern mi_decl_cache_align const mi_page_t _mi_page_empty;
void _mi_process_load(void);
void mi_cdecl _mi_process_done(void);
bool _mi_is_redirected(void);
bool _mi_allocator_init(const char** message);
void _mi_allocator_done(void);
bool _mi_is_main_thread(void);
size_t _mi_current_thread_count(void);
bool _mi_preloading(void); // true while the C runtime is not initialized yet
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114 changes: 6 additions & 108 deletions src/init.c
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Original file line number Diff line number Diff line change
Expand Up @@ -459,10 +459,6 @@ void mi_thread_init(void) mi_attr_noexcept
//_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
Expand Down Expand Up @@ -508,72 +504,30 @@ void _mi_heap_set_default_direct(mi_heap_t* 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) {
// Called once by the process loader from `src/prim/prim.c`
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");
if (_mi_is_redirected()) _mi_verbose_message("malloc is redirected.\n");

// show message from the redirector (if present)
const char* msg = NULL;
mi_allocator_init(&msg);
_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);
}
Expand Down Expand Up @@ -651,7 +605,7 @@ void mi_process_init(void) mi_attr_noexcept {
}

// Called when the process is done (through `at_exit`)
static void mi_cdecl mi_process_done(void) {
void mi_cdecl _mi_process_done(void) {
// only shutdown if we were initialized
if (!_mi_process_is_initialized) return;
// ensure we are called once
Expand Down Expand Up @@ -683,64 +637,8 @@ static void mi_cdecl mi_process_done(void) {
if (mi_option_is_enabled(mi_option_show_stats) || mi_option_is_enabled(mi_option_verbose)) {
mi_stats_print(NULL);
}
mi_allocator_done();
_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 <https://www.codeguru.com/cpp/misc/misc/applicationcontrol/article.php/c6945/Running-Code-Before-and-After-Main.htm>
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
44 changes: 44 additions & 0 deletions src/prim/prim.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,3 +25,47 @@ terms of the MIT license. A copy of the license can be found in the file
#include "unix/prim.c" // mmap() (Linux, macOSX, BSD, Illumnos, Haiku, DragonFly, etc.)

#endif

// Generic process initialization
#ifndef MI_PRIM_HAS_PROCESS_ATTACH
#if defined(__GNUC__) || defined(__clang__)
// GCC,Clang: use the constructor attribute
#if defined(__clang__)
#define mi_attr_constructor __attribute__((constructor(101)))
#define mi_attr_destructor __attribute__((destructor(101)))
#else
#define mi_attr_constructor __attribute__((constructor))
#define mi_attr_destructor __attribute__((destructor))
#endif
static void mi_attr_constructor mi_process_attach(void) {
_mi_process_load();
}
static void mi_attr_destructor mi_process_detach(void) {
_mi_process_done();
}
#elif defined(__cplusplus)
// C++: use static initialization to detect process start
static bool mi_process_attach(void) {
_mi_process_load();
atexit(&_mi_process_done);
return (_mi_heap_main.thread_id != 0);
}
static bool mi_initialized = mi_process_attach();
#else
#pragma message("define a way to call _mi_process_load/done on your platform")
#endif
#endif

// Generic allocator init/done callback
#ifndef MI_PRIM_HAS_ALLOCATOR_INIT
bool _mi_is_redirected(void) {
return false;
}
bool _mi_allocator_init(const char** message) {
if (message != NULL) *message = NULL;
return true;
}
void _mi_allocator_done(void) {
// nothing to do
}
#endif
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