| /* Implementation of W32-specific threads compatibility routines for |
| libgcc2. */ |
| |
| /* Copyright (C) 1999, 2000, 2002, 2004 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 2, 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. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING. If not, write to the Free |
| Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
| 02111-1307, USA. */ |
| |
| /* As a special exception, if you link this library with other files, |
| some of which are compiled with GCC, to produce an executable, |
| this library does not by itself cause the resulting executable |
| to be covered by the GNU General Public License. |
| This exception does not however invalidate any other reasons why |
| the executable file might be covered by the GNU General Public License. */ |
| |
| |
| #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 *)) |
| { |
| 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) |
| { |
| return (TlsSetValue (key, (void*) ptr) != 0) ? 0 : (int) GetLastError (); |
| } |
| |
| void |
| __gthr_win32_mutex_init_function (__gthread_mutex_t *mutex) |
| { |
| mutex->counter = -1; |
| mutex->sema = CreateSemaphore (NULL, 0, 65535, NULL); |
| } |
| |
| 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; |
| } |