[boehm] Add toggleref support for boehm. This is line by line port of…

… the sgen code, so keep them in sync.

libgc/darwin_stop_world.c

@@ -580,6 +580,7 @@ void GC_stop_world()
 
     if (GC_notify_event)
         GC_notify_event (GC_EVENT_PRE_STOP_WORLD);
+	GC_process_togglerefs ();
 
 #   if DEBUG_THREADS
       GC_printf1("Stopping the world from 0x%lx\n", mach_thread_self());

libgc/finalize.c

@@ -307,6 +307,164 @@ signed_word * log_size_ptr;
     return(0);
 }
 
+/* toggleref support */
+typedef struct {
+	GC_PTR strong_ref;
+	GC_hidden_pointer weak_ref;
+} GCToggleRef;
+
+static int (*GC_toggleref_callback) (GC_PTR obj);
+static GCToggleRef *GC_toggleref_array;
+static int GC_toggleref_array_size;
+static int GC_toggleref_array_capacity;
+
+
+void
+GC_process_togglerefs (void)
+{
+	int i, w;
+	int toggle_ref_counts [3] = { 0, 0, 0 };
+
+	for (i = w = 0; i < GC_toggleref_array_size; ++i) {
+		int res;
+		GCToggleRef r = GC_toggleref_array [i];
+
+		GC_PTR obj;
+
+		if (r.strong_ref)
+			obj = r.strong_ref;
+		else if (r.weak_ref)
+			obj = REVEAL_POINTER (r.weak_ref);
+		else
+			continue;
+
+		res = GC_toggleref_callback (obj);
+		++toggle_ref_counts [res];
+		switch (res) {
+		case 0:
+			break;
+		case 1:
+			GC_toggleref_array [w].strong_ref = obj;
+			GC_toggleref_array [w].weak_ref = (GC_hidden_pointer)NULL;
+			++w;
+			break;
+		case 2:
+			GC_toggleref_array [w].strong_ref = NULL;
+			GC_toggleref_array [w].weak_ref = HIDE_POINTER (obj);
+			++w;
+			break;
+		default:
+			ABORT("Invalid callback result");
+		}
+	}
+
+	for (i = w; i < GC_toggleref_array_size; ++i) {
+		GC_toggleref_array [w].strong_ref = NULL;
+		GC_toggleref_array [w].weak_ref = (GC_hidden_pointer)NULL;
+	}
+
+	GC_toggleref_array_size = w;
+}
+
+
+static void push_and_mark_object (GC_PTR p)
+{
+    hdr * hhdr = HDR(p);
+
+    PUSH_OBJ((word *)p, hhdr, GC_mark_stack_top,
+	     &(GC_mark_stack[GC_mark_stack_size]));
+
+	while (!GC_mark_stack_empty()) MARK_FROM_MARK_STACK();
+	GC_set_mark_bit (p);
+	if (GC_mark_state != MS_NONE)
+        while (!GC_mark_some((ptr_t)0)) {}
+}
+
+static void GC_mark_togglerefs ()
+{
+	int i;
+	if (!GC_toggleref_array)
+		return;
+
+	GC_set_mark_bit (GC_toggleref_array);
+	for (i = 0; i < GC_toggleref_array_size; ++i) {
+		if (GC_toggleref_array [i].strong_ref) {
+			GC_PTR object = GC_toggleref_array [i].strong_ref;
+
+			push_and_mark_object (object);
+		}
+	}
+}
+
+static void GC_clear_togglerefs ()
+{
+	int i;
+	for (i = 0; i < GC_toggleref_array_size; ++i) {
+		if (GC_toggleref_array [i].weak_ref) {
+			GC_PTR object = REVEAL_POINTER (GC_toggleref_array [i].weak_ref);
+
+			if (!GC_is_marked (object)) {
+				GC_toggleref_array [i].weak_ref = (GC_hidden_pointer)NULL; /* We defer compaction to only happen on the callback step. */
+			} else {
+				/*No need to copy, boehm is non-moving */
+			}
+		}
+	}
+}
+
+
+
+void GC_toggleref_register_callback(int (*proccess_toggleref) (GC_PTR obj))
+{
+	GC_toggleref_callback = proccess_toggleref;
+}
+
+static void
+ensure_toggleref_capacity (int capacity)
+{
+	if (!GC_toggleref_array) {
+		GC_toggleref_array_capacity = 32;
+		GC_toggleref_array = (GCToggleRef *) GC_INTERNAL_MALLOC (GC_toggleref_array_capacity * sizeof (GCToggleRef), NORMAL);
+	}
+	if (GC_toggleref_array_size + capacity >= GC_toggleref_array_capacity) {
+		GCToggleRef *tmp;
+		int old_capacity = GC_toggleref_array_capacity;
+		while (GC_toggleref_array_capacity < GC_toggleref_array_size + capacity)
+			GC_toggleref_array_capacity *= 2;
+
+		tmp = (GCToggleRef *) GC_INTERNAL_MALLOC (GC_toggleref_array_capacity * sizeof (GCToggleRef), NORMAL);
+		memcpy (tmp, GC_toggleref_array, GC_toggleref_array_size * sizeof (GCToggleRef));
+
+		GC_free((GC_PTR)GC_toggleref_array);
+		GC_toggleref_array = tmp;
+	}
+}
+
+void
+GC_toggleref_add (GC_PTR object, int strong_ref)
+{
+    DCL_LOCK_STATE;
+# ifdef THREADS
+	DISABLE_SIGNALS();
+	LOCK();
+# endif
+
+	if (!GC_toggleref_callback)
+		goto end;
+
+	ensure_toggleref_capacity (1);
+	GC_toggleref_array [GC_toggleref_array_size].strong_ref = strong_ref ? object : NULL;
+	GC_toggleref_array [GC_toggleref_array_size].weak_ref = strong_ref ? (GC_hidden_pointer)NULL : HIDE_POINTER (object);
+	++GC_toggleref_array_size;
+
+end:
+# ifdef THREADS
+	UNLOCK();
+	ENABLE_SIGNALS();
+# endif
+}
+
+
 
 # if defined(__STDC__) || defined(__cplusplus)
     int GC_register_long_link(GC_PTR * link, GC_PTR obj)
@@ -679,7 +837,9 @@ void GC_finalize()
     ptr_t real_ptr;
     register int i;
     int fo_size = (log_fo_table_size == -1 ) ? 0 : (1 << log_fo_table_size);
-
+
+	GC_mark_togglerefs();
+
   /* Make non-tracking disappearing links disappear */
 	GC_make_disappearing_links_disappear(&GC_dl_hashtbl);
 
@@ -755,6 +915,8 @@ void GC_finalize()
   /* Remove dangling disappearing links. */
   GC_remove_dangling_disappearing_links(&GC_dl_hashtbl);
 
+	GC_clear_togglerefs ();
+
   /* Make long links disappear and remove dangling ones. */
   GC_make_disappearing_links_disappear(&GC_ll_hashtbl);
   GC_remove_dangling_disappearing_links(&GC_ll_hashtbl);

libgc/include/gc.h

@@ -769,6 +769,11 @@ GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
 GC_API int GC_register_long_link GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
 GC_API int GC_unregister_long_link GC_PROTO((GC_PTR * /* link */));
 
+
+/* toggleref support */
+GC_API void GC_toggleref_register_callback GC_PROTO((int (*proccess_toggleref) (GC_PTR obj)));
+GC_API void GC_toggleref_add (GC_PTR object, int strong_ref);
+
 /* Returns !=0  if GC_invoke_finalizers has something to do. 		*/
 GC_API int GC_should_invoke_finalizers GC_PROTO((void));
 

libgc/include/private/gc_priv.h

@@ -1688,6 +1688,9 @@ void GC_finalize GC_PROTO((void));
   			/* for processing by GC_invoke_finalizers.	*/
   			/* Invoked with lock.				*/
 
+void GC_process_togglerefs (void);
+	/*Process the togglerefs before GC starts */
+
 void GC_notify_or_invoke_finalizers GC_PROTO((void));
 			/* If GC_finalize_on_demand is not set, invoke	*/
 			/* eligible finalizers. Otherwise:		*/

libgc/pthread_stop_world.c

@@ -611,6 +611,7 @@ void GC_stop_world()
 {
     if (GC_notify_event)
         GC_notify_event (GC_EVENT_PRE_STOP_WORLD);
+	GC_process_togglerefs ();
     /* Make sure all free list construction has stopped before we start. */
     /* No new construction can start, since free list construction is	*/
     /* required to acquire and release the GC lock before it starts,	*/