Merged GC 5.0alpha4 with local changes, plus:

[pf3gnuchains/gcc-fork.git] / boehm-gc / win32_threads.c

diff --git a/boehm-gc/win32_threads.c b/boehm-gc/win32_threads.c
index eb485bd..f6f74bd 100644 (file)
--- a/boehm-gc/win32_threads.c
+++ b/boehm-gc/win32_threads.c
@@ -8,22 +8,32 @@
 #define MAX_THREADS 64
 
 struct thread_entry {
+  LONG in_use;
   DWORD id;
   HANDLE handle;
-  void *stack;   /* The cold end of the stack. */
+  void *stack;         /* The cold end of the stack.   */
+                       /* 0 ==> entry not valid.       */
+                       /* !in_use ==> stack == 0       */
   CONTEXT context;
+  GC_bool suspended;
 };
 
-struct thread_entry thread_table[MAX_THREADS];
+volatile GC_bool GC_please_stop = FALSE;
+
+volatile struct thread_entry thread_table[MAX_THREADS];
 
 void GC_stop_world()
 {
   DWORD thread_id = GetCurrentThreadId();
   int i;
+
+  GC_please_stop = TRUE;
   for (i = 0; i < MAX_THREADS; i++)
-    if (thread_table[i].stack != 0 && thread_table[i].id != thread_id) {
+    if (thread_table[i].stack != 0
+       && thread_table[i].id != thread_id) {
       if (SuspendThread(thread_table[i].handle) == (DWORD)-1)
        ABORT("SuspendThread failed");
+      thread_table[i].suspended = TRUE;
     }
 }
 
@@ -32,10 +42,13 @@ void GC_start_world()
   DWORD thread_id = GetCurrentThreadId();
   int i;
   for (i = 0; i < MAX_THREADS; i++)
-    if (thread_table[i].stack != 0 && thread_table[i].id != thread_id) {
+    if (thread_table[i].stack != 0 && thread_table[i].suspended
+       && thread_table[i].id != thread_id) {
       if (ResumeThread(thread_table[i].handle) == (DWORD)-1)
        ABORT("ResumeThread failed");
+      thread_table[i].suspended = FALSE;
     }
+  GC_please_stop = FALSE;
 }
 
 ptr_t GC_current_stackbottom()
@@ -78,6 +91,12 @@ void GC_push_all_stacks()
        if (thread_table[i].context.Esp >= (DWORD)thread_table[i].stack
            || thread_table[i].context.Esp < (DWORD)bottom)
            ABORT("Thread stack pointer out of range");
+       GC_push_one ((word) thread_table[i].context.Edi);
+       GC_push_one ((word) thread_table[i].context.Esi);
+       GC_push_one ((word) thread_table[i].context.Ebx);
+       GC_push_one ((word) thread_table[i].context.Edx);
+       GC_push_one ((word) thread_table[i].context.Ecx);
+       GC_push_one ((word) thread_table[i].context.Eax);
        GC_push_all_stack(thread_table[i].context.Esp, thread_table[i].stack);
       }
     }
@@ -117,20 +136,34 @@ BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
   switch (reason) {
   case DLL_PROCESS_ATTACH:
     InitializeCriticalSection(&GC_allocate_ml);
+    GC_init(); /* Force initialization before thread attach.   */
     /* fall through */
   case DLL_THREAD_ATTACH:
     {
       int i;
-      LOCK();
+      /* It appears to be unsafe to acquire a lock here, since this    */
+      /* code is apparently not preeemptible on some systems.          */
+      /* (This is based on complaints, not on Microsoft's official     */
+      /* documentation, which says this should perform "only simple    */
+      /* inititalization tasks".)                                      */
+      /* Hence we make do with nonblocking synchronization.            */
+
       /* The following should be a noop according to the win32 */
       /* documentation.  There is empirical evidence that it   */
       /* isn't.                - HB                                    */
-      if (GC_incremental) SetUnhandledExceptionFilter(GC_write_fault_handler);
-      for (i = 0; thread_table[i].stack != 0; i++) {
+#     ifndef SMALL_CONFIG
+       if (GC_incremental) SetUnhandledExceptionFilter(GC_write_fault_handler);
+#     endif
+
+      for (i = 0; InterlockedExchange(&thread_table[i].in_use,1) != 0; i++) {
+       /* Compare-and-swap would make this cleaner, but that's not     */
+       /* supported before Windows 98 and NT 4.0.  In Windows 2000,    */
+       /* InterlockedExchange is supposed to be replaced by            */
+       /* InterlockedExchangePointer, but that's not really what I     */
+       /* want here.                                                   */
        if (i == MAX_THREADS - 1)
          ABORT("too many threads");
       }
-      thread_table[i].stack = GC_get_stack_base();
       thread_table[i].id = GetCurrentThreadId();
       if (!DuplicateHandle(GetCurrentProcess(),
                           GetCurrentThread(),
@@ -143,7 +176,11 @@ BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
            GC_printf1("Last error code: %lx\n", last_error);
            ABORT("DuplicateHandle failed");
       }
-      UNLOCK();
+      thread_table[i].stack = GC_get_stack_base();
+      /* If this thread is being created while we are trying to stop   */
+      /* the world, wait here.  Hopefully this can't happen on any     */
+      /* systems that don't allow us to block here.                    */
+      while (GC_please_stop) Sleep(20);
     }
     break;
   case DLL_PROCESS_DETACH:
@@ -152,10 +189,14 @@ BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
       int i;
       DWORD thread_id = GetCurrentThreadId();
       LOCK();
-      for (i = 0; thread_table[i].stack == 0 || thread_table[i].id != thread_id; i++)
+      for (i = 0;
+           thread_table[i].stack == 0 || thread_table[i].id != thread_id;
+          i++) {
        if (i == MAX_THREADS - 1)
          ABORT("thread not found on detach");
+      }
       thread_table[i].stack = 0;
+      thread_table[i].in_use = FALSE;
       CloseHandle(thread_table[i].handle);
       BZERO(&thread_table[i].context, sizeof(CONTEXT));
       UNLOCK();