* unreachable objects. We use it in monodroid to do garbage collection across
* the Mono and Java heaps.
*
- * The client can designate some objects as "bridged", which means that they
- * participate in the bridge processing step once SGen considers them
+ * The client (Monodroid) can designate some objects as "bridged", which means
+ * that they participate in the bridge processing step once SGen considers them
* unreachable, i.e., dead. Bridged objects must be registered for
* finalization.
*
* When SGen is done marking, it puts together a list of all dead bridged
- * objects and then does a strongly connected component analysis over their
- * object graph. That graph will usually contain non-bridged objects, too.
+ * objects. This is passed to the bridge processor, which does an analysis to
+ * simplify the graph: It replaces strongly-connected components with single
+ * nodes, and may remove nodes corresponding to components which do not contain
+ * bridged objects.
*
- * The output of the SCC analysis is passed to the `cross_references()`
- * callback. It is expected to set the `is_alive` flag on those strongly
- * connected components that it wishes to be kept alive. Only bridged objects
- * will be reported to the callback, i.e., non-bridged objects are removed from
- * the callback graph.
+ * The output of the SCC analysis is passed to the client's `cross_references()`
+ * callback. This consists of 2 arrays, an array of SCCs (MonoGCBridgeSCC),
+ * and an array of "xrefs" (edges between SCCs, MonoGCBridgeXRef). Edges are
+ * encoded as pairs of "API indices", ie indexes in the SCC array. The client
+ * is expected to set the `is_alive` flag on those strongly connected components
+ * that it wishes to be kept alive.
*
* In monodroid each bridged object has a corresponding Java mirror object. In
* the bridge callback it reifies the Mono object graph in the Java heap so that
* point all links to bridged objects that don't have `is_alive` set are nulled.
* Note that weak links to non-bridged objects reachable from bridged objects
* are not nulled. This might be considered a bug.
+ *
+ * There are three different implementations of the bridge processor, each of
+ * which implements 8 callbacks (see SgenBridgeProcessor). The implementations
+ * differ in the algorithm they use to compute the "simplified" SCC graph.
*/
#ifndef _MONO_SGEN_BRIDGE_H_
MONO_BEGIN_DECLS
enum {
- SGEN_BRIDGE_VERSION = 4
+ SGEN_BRIDGE_VERSION = 5
};
typedef enum {
void (*cross_references) (int num_sccs, MonoGCBridgeSCC **sccs, int num_xrefs, MonoGCBridgeXRef *xrefs);
} MonoGCBridgeCallbacks;
+/*
+ * Note: This may be called at any time, but cannot be called concurrently
+ * with (during and on a separate thread from) sgen init. Callers are
+ * responsible for enforcing this.
+ */
MONO_API void mono_gc_register_bridge_callbacks (MonoGCBridgeCallbacks *callbacks);
MONO_API void mono_gc_wait_for_bridge_processing (void);