-/* Threads compatibily routines for libgcc2. */
+/* Threads compatibility routines for libgcc2 and libobjc. */
/* Compile this one with gcc. */
-/* Copyright (C) 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1999, 2000 Free Software Foundation, Inc.
Contributed by Mumit Khan <khan@xraylith.wisc.edu>.
This file is part of GNU CC.
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. This
- will certainly cause memory leaks due to unreclaimed eh contexts
- (sizeof (eh_context) is at least 24 bytes for x86 currently).
+ 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 might consider using Critical Sections instead of Windows32
+ mutexes for better performance, but emulating __gthread_mutex_trylock
+ interface becomes more complicated (Win9x does not support
+ TryEnterCriticalSectioni, while NT does).
- The basic framework should work well enough. */
+ The basic framework should work well enough. In the long term, GCC
+ needs to use Structured Exception Handling on Windows32. */
#define __GTHREADS 1
#include <windows.h>
-#include <errno.h>
+
+#ifdef _LIBOBJC
+
+/* Key structure for maintaining thread specific storage */
+static DWORD __gthread_objc_data_tls = (DWORD)-1;
+
+/* Backend initialization functions */
+
+/* Initialize the threads subsystem. */
+int
+__gthread_objc_init_thread_system(void)
+{
+ /* Initialize the thread storage key */
+ if ((__gthread_objc_data_tls = TlsAlloc()) != (DWORD)-1)
+ return 0;
+ else
+ return -1;
+}
+
+/* Close the threads subsystem. */
+int
+__gthread_objc_close_thread_system(void)
+{
+ if (__gthread_objc_data_tls != (DWORD)-1)
+ TlsFree(__gthread_objc_data_tls);
+ return 0;
+}
+
+/* Backend thread functions */
+
+/* Create a new thread of execution. */
+objc_thread_t
+__gthread_objc_thread_detach(void (*func)(void *arg), void *arg)
+{
+ DWORD thread_id = 0;
+ HANDLE win32_handle;
+
+ if (!(win32_handle = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)func,
+ arg, 0, &thread_id)))
+ thread_id = 0;
+
+ return (objc_thread_t)thread_id;
+}
+
+/* Set the current thread's priority. */
+int
+__gthread_objc_thread_set_priority(int priority)
+{
+ int sys_priority = 0;
+
+ switch (priority)
+ {
+ case OBJC_THREAD_INTERACTIVE_PRIORITY:
+ sys_priority = THREAD_PRIORITY_NORMAL;
+ break;
+ default:
+ case OBJC_THREAD_BACKGROUND_PRIORITY:
+ sys_priority = THREAD_PRIORITY_BELOW_NORMAL;
+ break;
+ case OBJC_THREAD_LOW_PRIORITY:
+ sys_priority = THREAD_PRIORITY_LOWEST;
+ break;
+ }
+
+ /* Change priority */
+ if (SetThreadPriority(GetCurrentThread(), sys_priority))
+ return 0;
+ else
+ return -1;
+}
+
+/* Return the current thread's priority. */
+int
+__gthread_objc_thread_get_priority(void)
+{
+ int sys_priority;
+
+ sys_priority = GetThreadPriority(GetCurrentThread());
+
+ switch (sys_priority)
+ {
+ case THREAD_PRIORITY_HIGHEST:
+ case THREAD_PRIORITY_TIME_CRITICAL:
+ case THREAD_PRIORITY_ABOVE_NORMAL:
+ case THREAD_PRIORITY_NORMAL:
+ return OBJC_THREAD_INTERACTIVE_PRIORITY;
+
+ default:
+ case THREAD_PRIORITY_BELOW_NORMAL:
+ return OBJC_THREAD_BACKGROUND_PRIORITY;
+
+ case THREAD_PRIORITY_IDLE:
+ case THREAD_PRIORITY_LOWEST:
+ return OBJC_THREAD_LOW_PRIORITY;
+ }
+
+ /* Couldn't get priority. */
+ return -1;
+}
+
+/* Yield our process time to another thread. */
+void
+__gthread_objc_thread_yield(void)
+{
+ Sleep(0);
+}
+
+/* Terminate the current thread. */
+int
+__gthread_objc_thread_exit(void)
+{
+ /* exit the thread */
+ ExitThread(__gthread_objc_thread_exit_status);
+
+ /* Failed if we reached here */
+ return -1;
+}
+
+/* Returns an integer value which uniquely describes a thread. */
+objc_thread_t
+__gthread_objc_thread_id(void)
+{
+ return (objc_thread_t)GetCurrentThreadId();
+}
+
+/* Sets the thread's local storage pointer. */
+int
+__gthread_objc_thread_set_data(void *value)
+{
+ if (TlsSetValue(__gthread_objc_data_tls, value))
+ return 0;
+ else
+ return -1;
+}
+
+/* Returns the thread's local storage pointer. */
+void *
+__gthread_objc_thread_get_data(void)
+{
+ return TlsGetValue(__gthread_objc_data_tls); /* Return thread data. */
+}
+
+/* Backend mutex functions */
+
+/* Allocate a mutex. */
+int
+__gthread_objc_mutex_allocate(objc_mutex_t mutex)
+{
+ if ((mutex->backend = (void *)CreateMutex(NULL, 0, NULL)) == NULL)
+ return -1;
+ else
+ return 0;
+}
+
+/* Deallocate a mutex. */
+int
+__gthread_objc_mutex_deallocate(objc_mutex_t mutex)
+{
+ CloseHandle((HANDLE)(mutex->backend));
+ return 0;
+}
+
+/* Grab a lock on a mutex. */
+int
+__gthread_objc_mutex_lock(objc_mutex_t mutex)
+{
+ int status;
+
+ status = WaitForSingleObject((HANDLE)(mutex->backend), INFINITE);
+ if (status != WAIT_OBJECT_0 && status != WAIT_ABANDONED)
+ return -1;
+ else
+ return 0;
+}
+
+/* Try to grab a lock on a mutex. */
+int
+__gthread_objc_mutex_trylock(objc_mutex_t mutex)
+{
+ int status;
+
+ status = WaitForSingleObject((HANDLE)(mutex->backend), 0);
+ if (status != WAIT_OBJECT_0 && status != WAIT_ABANDONED)
+ return -1;
+ else
+ return 0;
+}
+
+/* Unlock the mutex */
+int
+__gthread_objc_mutex_unlock(objc_mutex_t mutex)
+{
+ if (ReleaseMutex((HANDLE)(mutex->backend)) == 0)
+ return -1;
+ else
+ return 0;
+}
+
+/* Backend condition mutex functions */
+
+/* Allocate a condition. */
+int
+__gthread_objc_condition_allocate(objc_condition_t condition)
+{
+ /* Unimplemented. */
+ return -1;
+}
+
+/* Deallocate a condition. */
+int
+__gthread_objc_condition_deallocate(objc_condition_t condition)
+{
+ /* Unimplemented. */
+ return -1;
+}
+
+/* Wait on the condition */
+int
+__gthread_objc_condition_wait(objc_condition_t condition, objc_mutex_t mutex)
+{
+ /* Unimplemented. */
+ return -1;
+}
+
+/* Wake up all threads waiting on this condition. */
+int
+__gthread_objc_condition_broadcast(objc_condition_t condition)
+{
+ /* Unimplemented. */
+ return -1;
+}
+
+/* Wake up one thread waiting on this condition. */
+int
+__gthread_objc_condition_signal(objc_condition_t condition)
+{
+ /* Unimplemented. */
+ return -1;
+}
+
+#else /* _LIBOBJC */
+
+#ifdef __MINGW32__
+#include <_mingw.h>
+#endif
typedef DWORD __gthread_key_t;
#define __GTHREAD_ONCE_INIT {FALSE, -1}
#define __GTHREAD_MUTEX_INIT_FUNCTION __gthread_mutex_init_function
+#if __MINGW32_MAJOR_VERSION >= 1 || \
+ (__MINGW32_MAJOR_VERSION == 0 && __MINGW32_MINOR_VERSION > 2)
+#define MINGW32_SUPPORTS_MT_EH 1
+extern int __mingwthr_key_dtor PARAMS ((DWORD, void (*) (void *)));
+/* Mingw runtime >= v0.3 provides a magic variable that is set to non-zero
+ if -mthreads option was specified, or 0 otherwise. This is to get around
+ the lack of weak symbols in PE-COFF. */
+extern int _CRT_MT;
+#endif
+
static inline int
-__gthread_active_p ()
+__gthread_active_p (void)
{
+#ifdef MINGW32_SUPPORTS_MT_EH
+ return _CRT_MT;
+#else
return 1;
+#endif
}
static inline int
-__gthread_once (__gthread_once_t *once, void (*func) ())
+__gthread_once (__gthread_once_t *once, void (*func) (void))
{
if (! __gthread_active_p ())
return -1;
(*func) ();
once->done = TRUE;
}
- }
- else
- {
- /* Another thread is currently executing the code, so wait for it to
- finish; yield the CPU in the meantime. */
- while (! once->done)
- Sleep (0);
+ 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; to avoid leaks,
- we will have to figure something out in the future. */
+/* 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. */
static inline int
-__gthread_key_create (__gthread_key_t *key,
- void (*dtor) (void *) __attribute__((__unused__)))
+__gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
{
int status = 0;
DWORD tls_index = TlsAlloc ();
if (tls_index != 0xFFFFFFFF)
- *key = tls_index;
+ {
+ *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;
}
-/* Currently, this routine is never called since win32 keys don't support
- destructors. Hopefully we'll find a way in the future. */
+/* Currently, this routine is called only for Mingw runtime, and if
+ -mthreads option is chosen to link in the thread support DLL. */
static inline int
__gthread_key_dtor (__gthread_key_t key, void *ptr)
{
- int status = 0;
-
- /* Just reset the key value to zero. */
- if (ptr)
- status = (TlsSetValue (key, 0) != 0) ? 0 : (int) GetLastError ();
- return status;
+ /* Nothing needed. */
+ return 0;
}
-/* Currently, this routine is never called since win32 keys don't support
- destructors. Hopefully we'll find a way in the future. */
static inline int
__gthread_key_delete (__gthread_key_t key)
{
static inline int
__gthread_setspecific (__gthread_key_t key, const void *ptr)
{
- return (TlsSetValue (key, ptr) != 0) ? 0 : (int) GetLastError ();
+ return (TlsSetValue (key, (void*) ptr) != 0) ? 0 : (int) GetLastError ();
}
static inline void
return 0;
}
+#endif /* _LIBOBJC */
+
#endif /* not __gthr_win32_h */
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