Initial revision

1 files changed, 209 insertions, 0 deletions

diff --git a/gc/win32_threads.c b/gc/win32_threads.c
new file mode 100755
index 0000000..f6f74bd
--- /dev/null
+++ b/gc/win32_threads.c
@@ -0,0 +1,209 @@
+#ifdef WIN32_THREADS
+
+#include "gc_priv.h"
+
+#define STRICT
+#include <windows.h>
+
+#define MAX_THREADS 64
+
+struct thread_entry {
+  LONG in_use;
+  DWORD id;
+  HANDLE handle;
+  void *stack;		/* The cold end of the stack.   */
+			/* 0 ==> entry not valid.	*/
+			/* !in_use ==> stack == 0	*/
+  CONTEXT context;
+  GC_bool suspended;
+};
+
+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 (SuspendThread(thread_table[i].handle) == (DWORD)-1)
+	ABORT("SuspendThread failed");
+      thread_table[i].suspended = TRUE;
+    }
+}
+
+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].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()
+{
+  DWORD thread_id = GetCurrentThreadId();
+  int i;
+  for (i = 0; i < MAX_THREADS; i++)
+    if (thread_table[i].stack && thread_table[i].id == thread_id)
+      return thread_table[i].stack;
+  ABORT("no thread table entry for current thread");
+}
+
+ptr_t GC_get_lo_stack_addr(ptr_t s)
+{
+    ptr_t bottom;
+    MEMORY_BASIC_INFORMATION info;
+    VirtualQuery(s, &info, sizeof(info));
+    do {
+	bottom = info.BaseAddress;
+	VirtualQuery(bottom - 1, &info, sizeof(info));
+    } while ((info.Protect & PAGE_READWRITE) && !(info.Protect & PAGE_GUARD));
+    return(bottom);
+}
+
+void GC_push_all_stacks()
+{
+  DWORD thread_id = GetCurrentThreadId();
+  int i;
+  for (i = 0; i < MAX_THREADS; i++)
+    if (thread_table[i].stack) {
+      ptr_t bottom = GC_get_lo_stack_addr(thread_table[i].stack);
+      if (thread_table[i].id == thread_id)
+	GC_push_all(&i, thread_table[i].stack);
+      else {
+	thread_table[i].context.ContextFlags
+			= (CONTEXT_INTEGER|CONTEXT_CONTROL);
+	if (!GetThreadContext(thread_table[i].handle,
+	    		      &thread_table[i].context))
+	  ABORT("GetThreadContext failed");
+	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);
+      }
+    }
+}
+
+void GC_get_next_stack(char *start, char **lo, char **hi)
+{
+    int i;
+#   define ADDR_LIMIT (char *)(-1L)
+    char * current_min = ADDR_LIMIT;
+
+    for (i = 0; i < MAX_THREADS; i++) {
+    	char * s = (char *)thread_table[i].stack;
+
+	if (0 != s && s > start && s < current_min) {
+	    current_min = s;
+	}
+    }
+    *hi = current_min;
+    if (current_min == ADDR_LIMIT) {
+    	*lo = ADDR_LIMIT;
+	return;
+    }
+    *lo = GC_get_lo_stack_addr(current_min);
+    if (*lo < start) *lo = start;
+}
+
+LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info);
+
+/*
+ * This isn't generally safe, since DllMain is not premptible.
+ * If another thread holds the lock while this runs we're in trouble.
+ * Pontus Rydin suggests wrapping the thread start routine instead.
+ */
+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;
+      /* 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					*/
+#     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].id = GetCurrentThreadId();
+      if (!DuplicateHandle(GetCurrentProcess(),
+	                   GetCurrentThread(),
+			   GetCurrentProcess(),
+			   &thread_table[i].handle,
+			   0,
+			   0,
+			   DUPLICATE_SAME_ACCESS)) {
+	    DWORD last_error = GetLastError();
+	    GC_printf1("Last error code: %lx\n", last_error);
+	    ABORT("DuplicateHandle failed");
+      }
+      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:
+  case DLL_THREAD_DETACH:
+    {
+      int i;
+      DWORD thread_id = GetCurrentThreadId();
+      LOCK();
+      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();
+    }
+    break;
+  }
+  return TRUE;
+}
+
+#endif /* WIN32_THREADS */