diff options
Diffstat (limited to 'gcc-4.9/libgcc/config/i386/gthr-win32.c')
| -rw-r--r-- | gcc-4.9/libgcc/config/i386/gthr-win32.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/gcc-4.9/libgcc/config/i386/gthr-win32.c b/gcc-4.9/libgcc/config/i386/gthr-win32.c new file mode 100644 index 000000000..eec16b326 --- /dev/null +++ b/gcc-4.9/libgcc/config/i386/gthr-win32.c @@ -0,0 +1,267 @@ +/* Implementation of W32-specific threads compatibility routines for + libgcc2. */ + +/* Copyright (C) 1999-2014 Free Software Foundation, Inc. + Contributed by Mumit Khan <khan@xraylith.wisc.edu>. + Modified and moved to separate file by Danny Smith + <dannysmith@users.sourceforge.net>. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 3, or (at your option) any later +version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +Under Section 7 of GPL version 3, you are granted additional +permissions described in the GCC Runtime Library Exception, version +3.1, as published by the Free Software Foundation. + +You should have received a copy of the GNU General Public License and +a copy of the GCC Runtime Library Exception along with this program; +see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +<http://www.gnu.org/licenses/>. */ + +#include <windows.h> +#ifndef __GTHREAD_HIDE_WIN32API +# define __GTHREAD_HIDE_WIN32API 1 +#endif +#undef __GTHREAD_I486_INLINE_LOCK_PRIMITIVES +#define __GTHREAD_I486_INLINE_LOCK_PRIMITIVES +#include "gthr-win32.h" + +/* Windows32 threads specific definitions. The windows32 threading model + does not map well into pthread-inspired gcc's threading model, and so + there are caveats one needs to be aware of. + + 1. The destructor supplied to __gthread_key_create is ignored for + generic x86-win32 ports. This will certainly cause memory leaks + due to unreclaimed eh contexts (sizeof (eh_context) is at least + 24 bytes for x86 currently). + + This memory leak may be significant for long-running applications + that make heavy use of C++ EH. + + However, Mingw runtime (version 0.3 or newer) provides a mechanism + to emulate pthreads key dtors; the runtime provides a special DLL, + linked in if -mthreads option is specified, that runs the dtors in + the reverse order of registration when each thread exits. If + -mthreads option is not given, a stub is linked in instead of the + DLL, which results in memory leak. Other x86-win32 ports can use + the same technique of course to avoid the leak. + + 2. The error codes returned are non-POSIX like, and cast into ints. + This may cause incorrect error return due to truncation values on + hw where sizeof (DWORD) > sizeof (int). + + 3. We are currently using a special mutex instead of the Critical + Sections, since Win9x does not support TryEnterCriticalSection + (while NT does). + + The basic framework should work well enough. In the long term, GCC + needs to use Structured Exception Handling on Windows32. */ + +int +__gthr_win32_once (__gthread_once_t *once, void (*func) (void)) +{ + if (once == NULL || func == NULL) + return EINVAL; + + if (! once->done) + { + if (InterlockedIncrement (&(once->started)) == 0) + { + (*func) (); + once->done = TRUE; + } + else + { + /* Another thread is currently executing the code, so wait for it + to finish; yield the CPU in the meantime. If performance + does become an issue, the solution is to use an Event that + we wait on here (and set above), but that implies a place to + create the event before this routine is called. */ + while (! once->done) + Sleep (0); + } + } + return 0; +} + +/* Windows32 thread local keys don't support destructors; this leads to + leaks, especially in threaded applications making extensive use of + C++ EH. Mingw uses a thread-support DLL to work-around this problem. */ + +int +__gthr_win32_key_create (__gthread_key_t *key, + void (*dtor) (void *) __attribute__((unused))) +{ + int status = 0; + DWORD tls_index = TlsAlloc (); + if (tls_index != 0xFFFFFFFF) + { + *key = tls_index; +#ifdef MINGW32_SUPPORTS_MT_EH + /* Mingw runtime will run the dtors in reverse order for each thread + when the thread exits. */ + status = __mingwthr_key_dtor (*key, dtor); +#endif + } + else + status = (int) GetLastError (); + return status; +} + +int +__gthr_win32_key_delete (__gthread_key_t key) +{ + return (TlsFree (key) != 0) ? 0 : (int) GetLastError (); +} + +void * +__gthr_win32_getspecific (__gthread_key_t key) +{ + DWORD lasterror; + void *ptr; + lasterror = GetLastError(); + ptr = TlsGetValue(key); + SetLastError( lasterror ); + return ptr; +} + +int +__gthr_win32_setspecific (__gthread_key_t key, const void *ptr) +{ + if (TlsSetValue (key, CONST_CAST2(void *, const void *, ptr)) != 0) + return 0; + else + return GetLastError (); +} + +void +__gthr_win32_mutex_init_function (__gthread_mutex_t *mutex) +{ + mutex->counter = -1; + mutex->sema = CreateSemaphoreW (NULL, 0, 65535, NULL); +} + +void +__gthr_win32_mutex_destroy (__gthread_mutex_t *mutex) +{ + CloseHandle ((HANDLE) mutex->sema); +} + +int +__gthr_win32_mutex_lock (__gthread_mutex_t *mutex) +{ + if (InterlockedIncrement (&mutex->counter) == 0 || + WaitForSingleObject (mutex->sema, INFINITE) == WAIT_OBJECT_0) + return 0; + else + { + /* WaitForSingleObject returns WAIT_FAILED, and we can only do + some best-effort cleanup here. */ + InterlockedDecrement (&mutex->counter); + return 1; + } +} + +int +__gthr_win32_mutex_trylock (__gthread_mutex_t *mutex) +{ + if (__GTHR_W32_InterlockedCompareExchange (&mutex->counter, 0, -1) < 0) + return 0; + else + return 1; +} + +int +__gthr_win32_mutex_unlock (__gthread_mutex_t *mutex) +{ + if (InterlockedDecrement (&mutex->counter) >= 0) + return ReleaseSemaphore (mutex->sema, 1, NULL) ? 0 : 1; + else + return 0; +} + +void +__gthr_win32_recursive_mutex_init_function (__gthread_recursive_mutex_t *mutex) +{ + mutex->counter = -1; + mutex->depth = 0; + mutex->owner = 0; + mutex->sema = CreateSemaphoreW (NULL, 0, 65535, NULL); +} + +int +__gthr_win32_recursive_mutex_lock (__gthread_recursive_mutex_t *mutex) +{ + DWORD me = GetCurrentThreadId(); + if (InterlockedIncrement (&mutex->counter) == 0) + { + mutex->depth = 1; + mutex->owner = me; + } + else if (mutex->owner == me) + { + InterlockedDecrement (&mutex->counter); + ++(mutex->depth); + } + else if (WaitForSingleObject (mutex->sema, INFINITE) == WAIT_OBJECT_0) + { + mutex->depth = 1; + mutex->owner = me; + } + else + { + /* WaitForSingleObject returns WAIT_FAILED, and we can only do + some best-effort cleanup here. */ + InterlockedDecrement (&mutex->counter); + return 1; + } + return 0; +} + +int +__gthr_win32_recursive_mutex_trylock (__gthread_recursive_mutex_t *mutex) +{ + DWORD me = GetCurrentThreadId(); + if (__GTHR_W32_InterlockedCompareExchange (&mutex->counter, 0, -1) < 0) + { + mutex->depth = 1; + mutex->owner = me; + } + else if (mutex->owner == me) + ++(mutex->depth); + else + return 1; + + return 0; +} + +int +__gthr_win32_recursive_mutex_unlock (__gthread_recursive_mutex_t *mutex) +{ + --(mutex->depth); + if (mutex->depth == 0) + { + mutex->owner = 0; + + if (InterlockedDecrement (&mutex->counter) >= 0) + return ReleaseSemaphore (mutex->sema, 1, NULL) ? 0 : 1; + } + + return 0; +} + +int +__gthr_win32_recursive_mutex_destroy (__gthread_recursive_mutex_t *mutex) +{ + CloseHandle ((HANDLE) mutex->sema); + return 0; +} |