source: trunk/gc6.8/win32_threads.c

Last change on this file was 132, checked in by cinc, 19 years ago

Boehm-Demers-Weiser garbage collector. Single-threaded for OS/2.
File size: 22.5 KB
Line 
1#include "private/gc_priv.h"
2
3#if defined(GC_WIN32_THREADS)
4
5#include <windows.h>
6
7#ifdef CYGWIN32
8# include <errno.h>
9
10 /* Cygwin-specific forward decls */
11# undef pthread_create
12# undef pthread_sigmask
13# undef pthread_join
14# undef pthread_detach
15# undef dlopen
16
17# define DEBUG_CYGWIN_THREADS 0
18
19 void * GC_start_routine(void * arg);
20 void GC_thread_exit_proc(void *arg);
21
22#endif
23
24/* The type of the first argument to InterlockedExchange. */
25/* Documented to be LONG volatile *, but at least gcc likes */
26/* this better. */
27typedef LONG * IE_t;
28
29#ifndef MAX_THREADS
30# define MAX_THREADS 256
31 /* FIXME: */
32 /* Things may get quite slow for large numbers of threads, */
33 /* since we look them up with sequential search. */
34#endif
35
36GC_bool GC_thr_initialized = FALSE;
37
38DWORD GC_main_thread = 0;
39
40struct GC_thread_Rep {
41 LONG in_use; /* Updated without lock. */
42 /* We assert that unused */
43 /* entries have invalid ids of */
44 /* zero and zero stack fields. */
45 DWORD id;
46 HANDLE handle;
47 ptr_t stack_base; /* The cold end of the stack. */
48 /* 0 ==> entry not valid. */
49 /* !in_use ==> stack_base == 0 */
50 GC_bool suspended;
51
52# ifdef CYGWIN32
53 void *status; /* hold exit value until join in case it's a pointer */
54 pthread_t pthread_id;
55 short flags; /* Protected by GC lock. */
56# define FINISHED 1 /* Thread has exited. */
57# define DETACHED 2 /* Thread is intended to be detached. */
58# endif
59};
60
61typedef volatile struct GC_thread_Rep * GC_thread;
62
63/*
64 * We generally assume that volatile ==> memory ordering, at least among
65 * volatiles.
66 */
67
68volatile GC_bool GC_please_stop = FALSE;
69
70volatile struct GC_thread_Rep thread_table[MAX_THREADS];
71
72volatile LONG GC_max_thread_index = 0; /* Largest index in thread_table */
73 /* that was ever used. */
74
75extern LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info);
76
77/*
78 * This may be called from DllMain, and hence operates under unusual
79 * constraints.
80 */
81static GC_thread GC_new_thread(void) {
82 int i;
83 /* It appears to be unsafe to acquire a lock here, since this */
84 /* code is apparently not preeemptible on some systems. */
85 /* (This is based on complaints, not on Microsoft's official */
86 /* documentation, which says this should perform "only simple */
87 /* initialization tasks".) */
88 /* Hence we make do with nonblocking synchronization. */
89
90 /* The following should be a noop according to the win32 */
91 /* documentation. There is empirical evidence that it */
92 /* isn't. - HB */
93# if defined(MPROTECT_VDB)
94 if (GC_incremental) SetUnhandledExceptionFilter(GC_write_fault_handler);
95# endif
96 /* cast away volatile qualifier */
97 for (i = 0; InterlockedExchange((IE_t)&thread_table[i].in_use,1) != 0; i++) {
98 /* Compare-and-swap would make this cleaner, but that's not */
99 /* supported before Windows 98 and NT 4.0. In Windows 2000, */
100 /* InterlockedExchange is supposed to be replaced by */
101 /* InterlockedExchangePointer, but that's not really what I */
102 /* want here. */
103 if (i == MAX_THREADS - 1)
104 ABORT("too many threads");
105 }
106 /* Update GC_max_thread_index if necessary. The following is safe, */
107 /* and unlike CompareExchange-based solutions seems to work on all */
108 /* Windows95 and later platforms. */
109 /* Unfortunately, GC_max_thread_index may be temporarily out of */
110 /* bounds, so readers have to compensate. */
111 while (i > GC_max_thread_index) {
112 InterlockedIncrement((IE_t)&GC_max_thread_index);
113 }
114 if (GC_max_thread_index >= MAX_THREADS) {
115 /* We overshot due to simultaneous increments. */
116 /* Setting it to MAX_THREADS-1 is always safe. */
117 GC_max_thread_index = MAX_THREADS - 1;
118 }
119
120# ifdef CYGWIN32
121 thread_table[i].pthread_id = pthread_self();
122# endif
123 if (!DuplicateHandle(GetCurrentProcess(),
124 GetCurrentThread(),
125 GetCurrentProcess(),
126 (HANDLE*)&thread_table[i].handle,
127 0,
128 0,
129 DUPLICATE_SAME_ACCESS)) {
130 DWORD last_error = GetLastError();
131 GC_printf1("Last error code: %lx\n", last_error);
132 ABORT("DuplicateHandle failed");
133 }
134 thread_table[i].stack_base = GC_get_stack_base();
135 /* Up until this point, GC_push_all_stacks considers this thread */
136 /* invalid. */
137 if (thread_table[i].stack_base == NULL)
138 ABORT("Failed to find stack base in GC_new_thread");
139 /* Up until this point, this entry is viewed as reserved but invalid */
140 /* by GC_delete_thread. */
141 thread_table[i].id = GetCurrentThreadId();
142 /* If this thread is being created while we are trying to stop */
143 /* the world, wait here. Hopefully this can't happen on any */
144 /* systems that don't allow us to block here. */
145 while (GC_please_stop) Sleep(20);
146 return thread_table + i;
147}
148
149/*
150 * GC_max_thread_index may temporarily be larger than MAX_THREADS.
151 * To avoid subscript errors, we check on access.
152 */
153#ifdef __GNUC__
154__inline__
155#endif
156LONG GC_get_max_thread_index()
157{
158 LONG my_max = GC_max_thread_index;
159
160 if (my_max >= MAX_THREADS) return MAX_THREADS-1;
161 return my_max;
162}
163
164/* This is intended to be lock-free, though that */
165/* assumes that the CloseHandle becomes visible before the */
166/* in_use assignment. */
167static void GC_delete_gc_thread(GC_thread thr)
168{
169 CloseHandle(thr->handle);
170 /* cast away volatile qualifier */
171 thr->stack_base = 0;
172 thr->id = 0;
173# ifdef CYGWIN32
174 thr->pthread_id = 0;
175# endif /* CYGWIN32 */
176 thr->in_use = FALSE;
177}
178
179static void GC_delete_thread(DWORD thread_id) {
180 int i;
181 LONG my_max = GC_get_max_thread_index();
182
183 for (i = 0;
184 i <= my_max &&
185 (!thread_table[i].in_use || thread_table[i].id != thread_id);
186 /* Must still be in_use, since nobody else can store our thread_id. */
187 i++) {}
188 if (i > my_max) {
189 WARN("Removing nonexistent thread %ld\n", (GC_word)thread_id);
190 } else {
191 GC_delete_gc_thread(thread_table+i);
192 }
193}
194
195
196#ifdef CYGWIN32
197
198/* Return a GC_thread corresponding to a given pthread_t. */
199/* Returns 0 if it's not there. */
200/* We assume that this is only called for pthread ids that */
201/* have not yet terminated or are still joinable. */
202static GC_thread GC_lookup_thread(pthread_t id)
203{
204 int i;
205 LONG my_max = GC_get_max_thread_index();
206
207 for (i = 0;
208 i <= my_max &&
209 (!thread_table[i].in_use || thread_table[i].pthread_id != id
210 || !thread_table[i].in_use);
211 /* Must still be in_use, since nobody else can store our thread_id. */
212 i++);
213 if (i > my_max) return 0;
214 return thread_table + i;
215}
216
217#endif /* CYGWIN32 */
218
219void GC_push_thread_structures GC_PROTO((void))
220{
221 /* Unlike the other threads implementations, the thread table here */
222 /* contains no pointers to the collectable heap. Thus we have */
223 /* no private structures we need to preserve. */
224# ifdef CYGWIN32
225 { int i; /* pthreads may keep a pointer in the thread exit value */
226 LONG my_max = GC_get_max_thread_index();
227
228 for (i = 0; i <= my_max; i++)
229 if (thread_table[i].in_use)
230 GC_push_all((ptr_t)&(thread_table[i].status),
231 (ptr_t)(&(thread_table[i].status)+1));
232 }
233# endif
234}
235
236/* Defined in misc.c */
237extern CRITICAL_SECTION GC_write_cs;
238
239void GC_stop_world()
240{
241 DWORD thread_id = GetCurrentThreadId();
242 int i;
243
244 if (!GC_thr_initialized) ABORT("GC_stop_world() called before GC_thr_init()");
245
246 GC_please_stop = TRUE;
247# ifndef CYGWIN32
248 EnterCriticalSection(&GC_write_cs);
249# endif /* !CYGWIN32 */
250 for (i = 0; i <= GC_get_max_thread_index(); i++)
251 if (thread_table[i].stack_base != 0
252 && thread_table[i].id != thread_id) {
253# ifdef MSWINCE
254 /* SuspendThread will fail if thread is running kernel code */
255 while (SuspendThread(thread_table[i].handle) == (DWORD)-1)
256 Sleep(10);
257# else
258 /* Apparently the Windows 95 GetOpenFileName call creates */
259 /* a thread that does not properly get cleaned up, and */
260 /* SuspendThread on its descriptor may provoke a crash. */
261 /* This reduces the probability of that event, though it still */
262 /* appears there's a race here. */
263 DWORD exitCode;
264 if (GetExitCodeThread(thread_table[i].handle,&exitCode) &&
265 exitCode != STILL_ACTIVE) {
266 thread_table[i].stack_base = 0; /* prevent stack from being pushed */
267# ifndef CYGWIN32
268 /* this breaks pthread_join on Cygwin, which is guaranteed to */
269 /* only see user pthreads */
270 thread_table[i].in_use = FALSE;
271 CloseHandle(thread_table[i].handle);
272# endif
273 continue;
274 }
275 if (SuspendThread(thread_table[i].handle) == (DWORD)-1)
276 ABORT("SuspendThread failed");
277# endif
278 thread_table[i].suspended = TRUE;
279 }
280# ifndef CYGWIN32
281 LeaveCriticalSection(&GC_write_cs);
282# endif /* !CYGWIN32 */
283}
284
285void GC_start_world()
286{
287 DWORD thread_id = GetCurrentThreadId();
288 int i;
289 LONG my_max = GC_get_max_thread_index();
290
291 for (i = 0; i <= my_max; i++)
292 if (thread_table[i].stack_base != 0 && thread_table[i].suspended
293 && thread_table[i].id != thread_id) {
294 if (ResumeThread(thread_table[i].handle) == (DWORD)-1)
295 ABORT("ResumeThread failed");
296 thread_table[i].suspended = FALSE;
297 }
298 GC_please_stop = FALSE;
299}
300
301# ifdef _MSC_VER
302# pragma warning(disable:4715)
303# endif
304ptr_t GC_current_stackbottom()
305{
306 DWORD thread_id = GetCurrentThreadId();
307 int i;
308 LONG my_max = GC_get_max_thread_index();
309
310 for (i = 0; i <= my_max; i++)
311 if (thread_table[i].stack_base && thread_table[i].id == thread_id)
312 return thread_table[i].stack_base;
313 ABORT("no thread table entry for current thread");
314}
315# ifdef _MSC_VER
316# pragma warning(default:4715)
317# endif
318
319# ifdef MSWINCE
320 /* The VirtualQuery calls below won't work properly on WinCE, but */
321 /* since each stack is restricted to an aligned 64K region of */
322 /* virtual memory we can just take the next lowest multiple of 64K. */
323# define GC_get_stack_min(s) \
324 ((ptr_t)(((DWORD)(s) - 1) & 0xFFFF0000))
325# else
326 static ptr_t GC_get_stack_min(ptr_t s)
327 {
328 ptr_t bottom;
329 MEMORY_BASIC_INFORMATION info;
330 VirtualQuery(s, &info, sizeof(info));
331 do {
332 bottom = info.BaseAddress;
333 VirtualQuery(bottom - 1, &info, sizeof(info));
334 } while ((info.Protect & PAGE_READWRITE)
335 && !(info.Protect & PAGE_GUARD));
336 return(bottom);
337 }
338# endif
339
340void GC_push_all_stacks()
341{
342 DWORD thread_id = GetCurrentThreadId();
343 GC_bool found_me = FALSE;
344 int i;
345 int dummy;
346 ptr_t sp, stack_min;
347 GC_thread thread;
348 LONG my_max = GC_get_max_thread_index();
349
350 for (i = 0; i <= my_max; i++) {
351 thread = thread_table + i;
352 if (thread -> in_use && thread -> stack_base) {
353 if (thread -> id == thread_id) {
354 sp = (ptr_t) &dummy;
355 found_me = TRUE;
356 } else {
357 CONTEXT context;
358 context.ContextFlags = CONTEXT_INTEGER|CONTEXT_CONTROL;
359 if (!GetThreadContext(thread_table[i].handle, &context))
360 ABORT("GetThreadContext failed");
361
362 /* Push all registers that might point into the heap. Frame */
363 /* pointer registers are included in case client code was */
364 /* compiled with the 'omit frame pointer' optimisation. */
365# define PUSH1(reg) GC_push_one((word)context.reg)
366# define PUSH2(r1,r2) PUSH1(r1), PUSH1(r2)
367# define PUSH4(r1,r2,r3,r4) PUSH2(r1,r2), PUSH2(r3,r4)
368# if defined(I386)
369 PUSH4(Edi,Esi,Ebx,Edx), PUSH2(Ecx,Eax), PUSH1(Ebp);
370 sp = (ptr_t)context.Esp;
371# elif defined(ARM32)
372 PUSH4(R0,R1,R2,R3),PUSH4(R4,R5,R6,R7),PUSH4(R8,R9,R10,R11),PUSH1(R12);
373 sp = (ptr_t)context.Sp;
374# elif defined(SHx)
375 PUSH4(R0,R1,R2,R3), PUSH4(R4,R5,R6,R7), PUSH4(R8,R9,R10,R11);
376 PUSH2(R12,R13), PUSH1(R14);
377 sp = (ptr_t)context.R15;
378# elif defined(MIPS)
379 PUSH4(IntAt,IntV0,IntV1,IntA0), PUSH4(IntA1,IntA2,IntA3,IntT0);
380 PUSH4(IntT1,IntT2,IntT3,IntT4), PUSH4(IntT5,IntT6,IntT7,IntS0);
381 PUSH4(IntS1,IntS2,IntS3,IntS4), PUSH4(IntS5,IntS6,IntS7,IntT8);
382 PUSH4(IntT9,IntK0,IntK1,IntS8);
383 sp = (ptr_t)context.IntSp;
384# elif defined(PPC)
385 PUSH4(Gpr0, Gpr3, Gpr4, Gpr5), PUSH4(Gpr6, Gpr7, Gpr8, Gpr9);
386 PUSH4(Gpr10,Gpr11,Gpr12,Gpr14), PUSH4(Gpr15,Gpr16,Gpr17,Gpr18);
387 PUSH4(Gpr19,Gpr20,Gpr21,Gpr22), PUSH4(Gpr23,Gpr24,Gpr25,Gpr26);
388 PUSH4(Gpr27,Gpr28,Gpr29,Gpr30), PUSH1(Gpr31);
389 sp = (ptr_t)context.Gpr1;
390# elif defined(ALPHA)
391 PUSH4(IntV0,IntT0,IntT1,IntT2), PUSH4(IntT3,IntT4,IntT5,IntT6);
392 PUSH4(IntT7,IntS0,IntS1,IntS2), PUSH4(IntS3,IntS4,IntS5,IntFp);
393 PUSH4(IntA0,IntA1,IntA2,IntA3), PUSH4(IntA4,IntA5,IntT8,IntT9);
394 PUSH4(IntT10,IntT11,IntT12,IntAt);
395 sp = (ptr_t)context.IntSp;
396# else
397# error "architecture is not supported"
398# endif
399 }
400
401 stack_min = GC_get_stack_min(thread->stack_base);
402
403 if (sp >= stack_min && sp < thread->stack_base)
404 GC_push_all_stack(sp, thread->stack_base);
405 else {
406 WARN("Thread stack pointer 0x%lx out of range, pushing everything\n",
407 (unsigned long)sp);
408 GC_push_all_stack(stack_min, thread->stack_base);
409 }
410 }
411 }
412 if (!found_me) ABORT("Collecting from unknown thread.");
413}
414
415void GC_get_next_stack(char *start, char **lo, char **hi)
416{
417 int i;
418# define ADDR_LIMIT (char *)(-1L)
419 char * current_min = ADDR_LIMIT;
420 LONG my_max = GC_get_max_thread_index();
421
422 for (i = 0; i <= my_max; i++) {
423 char * s = (char *)thread_table[i].stack_base;
424
425 if (0 != s && s > start && s < current_min) {
426 current_min = s;
427 }
428 }
429 *hi = current_min;
430 if (current_min == ADDR_LIMIT) {
431 *lo = ADDR_LIMIT;
432 return;
433 }
434 *lo = GC_get_stack_min(current_min);
435 if (*lo < start) *lo = start;
436}
437
438#if !defined(CYGWIN32)
439
440#if !defined(MSWINCE) && defined(GC_DLL)
441
442/* We register threads from DllMain */
443
444GC_API HANDLE WINAPI GC_CreateThread(
445 LPSECURITY_ATTRIBUTES lpThreadAttributes,
446 DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
447 LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId )
448{
449 return CreateThread(lpThreadAttributes, dwStackSize, lpStartAddress,
450 lpParameter, dwCreationFlags, lpThreadId);
451}
452
453#else /* defined(MSWINCE) || !defined(GC_DLL)) */
454
455/* We have no DllMain to take care of new threads. Thus we */
456/* must properly intercept thread creation. */
457
458typedef struct {
459 LPTHREAD_START_ROUTINE start;
460 LPVOID param;
461} thread_args;
462
463static DWORD WINAPI thread_start(LPVOID arg);
464
465GC_API HANDLE WINAPI GC_CreateThread(
466 LPSECURITY_ATTRIBUTES lpThreadAttributes,
467 DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
468 LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId )
469{
470 HANDLE thread_h = NULL;
471
472 thread_args *args;
473
474 if (!GC_is_initialized) GC_init();
475 /* make sure GC is initialized (i.e. main thread is attached) */
476
477 args = GC_malloc_uncollectable(sizeof(thread_args));
478 /* Handed off to and deallocated by child thread. */
479 if (0 == args) {
480 SetLastError(ERROR_NOT_ENOUGH_MEMORY);
481 return NULL;
482 }
483
484 /* set up thread arguments */
485 args -> start = lpStartAddress;
486 args -> param = lpParameter;
487
488 thread_h = CreateThread(lpThreadAttributes,
489 dwStackSize, thread_start,
490 args, dwCreationFlags,
491 lpThreadId);
492
493 return thread_h;
494}
495
496static DWORD WINAPI thread_start(LPVOID arg)
497{
498 DWORD ret = 0;
499 thread_args *args = (thread_args *)arg;
500
501 GC_new_thread();
502
503 /* Clear the thread entry even if we exit with an exception. */
504 /* This is probably pointless, since an uncaught exception is */
505 /* supposed to result in the process being killed. */
506#ifndef __GNUC__
507 __try {
508#endif /* __GNUC__ */
509 ret = args->start (args->param);
510#ifndef __GNUC__
511 } __finally {
512#endif /* __GNUC__ */
513 GC_free(args);
514 GC_delete_thread(GetCurrentThreadId());
515#ifndef __GNUC__
516 }
517#endif /* __GNUC__ */
518
519 return ret;
520}
521#endif /* !defined(MSWINCE) && !(defined(__MINGW32__) && !defined(_DLL)) */
522
523#endif /* !CYGWIN32 */
524
525#ifdef MSWINCE
526
527typedef struct {
528 HINSTANCE hInstance;
529 HINSTANCE hPrevInstance;
530 LPWSTR lpCmdLine;
531 int nShowCmd;
532} main_thread_args;
533
534DWORD WINAPI main_thread_start(LPVOID arg);
535
536int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
537 LPWSTR lpCmdLine, int nShowCmd)
538{
539 DWORD exit_code = 1;
540
541 main_thread_args args = {
542 hInstance, hPrevInstance, lpCmdLine, nShowCmd
543 };
544 HANDLE thread_h;
545 DWORD thread_id;
546
547 /* initialize everything */
548 GC_init();
549
550 /* start the main thread */
551 thread_h = GC_CreateThread(
552 NULL, 0, main_thread_start, &args, 0, &thread_id);
553
554 if (thread_h != NULL)
555 {
556 WaitForSingleObject (thread_h, INFINITE);
557 GetExitCodeThread (thread_h, &exit_code);
558 CloseHandle (thread_h);
559 }
560
561 GC_deinit();
562 DeleteCriticalSection(&GC_allocate_ml);
563
564 return (int) exit_code;
565}
566
567DWORD WINAPI main_thread_start(LPVOID arg)
568{
569 main_thread_args * args = (main_thread_args *) arg;
570
571 return (DWORD) GC_WinMain (args->hInstance, args->hPrevInstance,
572 args->lpCmdLine, args->nShowCmd);
573}
574
575# else /* !MSWINCE */
576
577/* Called by GC_init() - we hold the allocation lock. */
578void GC_thr_init() {
579 if (GC_thr_initialized) return;
580 GC_main_thread = GetCurrentThreadId();
581 GC_thr_initialized = TRUE;
582
583 /* Add the initial thread, so we can stop it. */
584 GC_new_thread();
585}
586
587#ifdef CYGWIN32
588
589struct start_info {
590 void *(*start_routine)(void *);
591 void *arg;
592 GC_bool detached;
593};
594
595int GC_pthread_join(pthread_t pthread_id, void **retval) {
596 int result;
597 int i;
598 GC_thread me;
599
600# if DEBUG_CYGWIN_THREADS
601 GC_printf3("thread 0x%x(0x%x) is joining thread 0x%x.\n",
602 (int)pthread_self(), GetCurrentThreadId(), (int)pthread_id);
603# endif
604
605 /* Thread being joined might not have registered itself yet. */
606 /* After the join,thread id may have been recycled. */
607 /* FIXME: It would be better if this worked more like */
608 /* pthread_support.c. */
609
610 while ((me = GC_lookup_thread(pthread_id)) == 0) Sleep(10);
611
612 result = pthread_join(pthread_id, retval);
613
614 GC_delete_gc_thread(me);
615
616# if DEBUG_CYGWIN_THREADS
617 GC_printf3("thread 0x%x(0x%x) completed join with thread 0x%x.\n",
618 (int)pthread_self(), GetCurrentThreadId(), (int)pthread_id);
619# endif
620
621 return result;
622}
623
624/* Cygwin-pthreads calls CreateThread internally, but it's not
625 * easily interceptible by us..
626 * so intercept pthread_create instead
627 */
628int
629GC_pthread_create(pthread_t *new_thread,
630 const pthread_attr_t *attr,
631 void *(*start_routine)(void *), void *arg) {
632 int result;
633 struct start_info * si;
634
635 if (!GC_is_initialized) GC_init();
636 /* make sure GC is initialized (i.e. main thread is attached) */
637
638 /* This is otherwise saved only in an area mmapped by the thread */
639 /* library, which isn't visible to the collector. */
640 si = GC_malloc_uncollectable(sizeof(struct start_info));
641 if (0 == si) return(EAGAIN);
642
643 si -> start_routine = start_routine;
644 si -> arg = arg;
645 if (attr != 0 &&
646 pthread_attr_getdetachstate(attr, &si->detached)
647 == PTHREAD_CREATE_DETACHED) {
648 si->detached = TRUE;
649 }
650
651# if DEBUG_CYGWIN_THREADS
652 GC_printf2("About to create a thread from 0x%x(0x%x)\n",
653 (int)pthread_self(), GetCurrentThreadId);
654# endif
655 result = pthread_create(new_thread, attr, GC_start_routine, si);
656
657 if (result) { /* failure */
658 GC_free(si);
659 }
660
661 return(result);
662}
663
664void * GC_start_routine(void * arg)
665{
666 struct start_info * si = arg;
667 void * result;
668 void *(*start)(void *);
669 void *start_arg;
670 pthread_t pthread_id;
671 GC_thread me;
672 GC_bool detached;
673 int i;
674
675# if DEBUG_CYGWIN_THREADS
676 GC_printf2("thread 0x%x(0x%x) starting...\n",(int)pthread_self(),
677 GetCurrentThreadId());
678# endif
679
680 /* If a GC occurs before the thread is registered, that GC will */
681 /* ignore this thread. That's fine, since it will block trying to */
682 /* acquire the allocation lock, and won't yet hold interesting */
683 /* pointers. */
684 LOCK();
685 /* We register the thread here instead of in the parent, so that */
686 /* we don't need to hold the allocation lock during pthread_create. */
687 me = GC_new_thread();
688 UNLOCK();
689
690 start = si -> start_routine;
691 start_arg = si -> arg;
692 if (si-> detached) me -> flags |= DETACHED;
693 me -> pthread_id = pthread_id = pthread_self();
694
695 GC_free(si); /* was allocated uncollectable */
696
697 pthread_cleanup_push(GC_thread_exit_proc, (void *)me);
698 result = (*start)(start_arg);
699 me -> status = result;
700 pthread_cleanup_pop(0);
701
702# if DEBUG_CYGWIN_THREADS
703 GC_printf2("thread 0x%x(0x%x) returned from start routine.\n",
704 (int)pthread_self(),GetCurrentThreadId());
705# endif
706
707 return(result);
708}
709
710void GC_thread_exit_proc(void *arg)
711{
712 GC_thread me = (GC_thread)arg;
713 int i;
714
715# if DEBUG_CYGWIN_THREADS
716 GC_printf2("thread 0x%x(0x%x) called pthread_exit().\n",
717 (int)pthread_self(),GetCurrentThreadId());
718# endif
719
720 LOCK();
721 if (me -> flags & DETACHED) {
722 GC_delete_thread(GetCurrentThreadId());
723 } else {
724 /* deallocate it as part of join */
725 me -> flags |= FINISHED;
726 }
727 UNLOCK();
728}
729
730/* nothing required here... */
731int GC_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) {
732 return pthread_sigmask(how, set, oset);
733}
734
735int GC_pthread_detach(pthread_t thread)
736{
737 int result;
738 GC_thread thread_gc_id;
739
740 LOCK();
741 thread_gc_id = GC_lookup_thread(thread);
742 UNLOCK();
743 result = pthread_detach(thread);
744 if (result == 0) {
745 LOCK();
746 thread_gc_id -> flags |= DETACHED;
747 /* Here the pthread thread id may have been recycled. */
748 if (thread_gc_id -> flags & FINISHED) {
749 GC_delete_gc_thread(thread_gc_id);
750 }
751 UNLOCK();
752 }
753 return result;
754}
755
756#else /* !CYGWIN32 */
757
758/*
759 * We avoid acquiring locks here, since this doesn't seem to be preemptable.
760 * Pontus Rydin suggests wrapping the thread start routine instead.
761 */
762#ifdef GC_DLL
763BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
764{
765 switch (reason) {
766 case DLL_PROCESS_ATTACH:
767 GC_init(); /* Force initialization before thread attach. */
768 /* fall through */
769 case DLL_THREAD_ATTACH:
770 GC_ASSERT(GC_thr_initialized);
771 if (GC_main_thread != GetCurrentThreadId()) {
772 GC_new_thread();
773 } /* o.w. we already did it during GC_thr_init(), called by GC_init() */
774 break;
775
776 case DLL_THREAD_DETACH:
777 GC_delete_thread(GetCurrentThreadId());
778 break;
779
780 case DLL_PROCESS_DETACH:
781 {
782 int i;
783
784 LOCK();
785 for (i = 0; i <= GC_get_max_thread_index(); ++i)
786 {
787 if (thread_table[i].in_use)
788 GC_delete_gc_thread(thread_table + i);
789 }
790 UNLOCK();
791
792 GC_deinit();
793 DeleteCriticalSection(&GC_allocate_ml);
794 }
795 break;
796
797 }
798 return TRUE;
799}
800#endif /* GC_DLL */
801#endif /* !CYGWIN32 */
802
803# endif /* !MSWINCE */
804
805#endif /* GC_WIN32_THREADS */
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