[heap] Add basic infrastructure for incremental wrapper tracing.

BUG=chromium:468240

Review-Url: https://codereview.chromium.org/2245133004
Cr-Commit-Position: refs/heads/master@{#38702}

src/flag-definitions.h

@@ -740,6 +740,8 @@ DEFINE_BOOL(age_code, true,
             "track un-executed functions to age code and flush only "
             "old code (required for code flushing)")
 DEFINE_BOOL(incremental_marking, true, "use incremental marking")
+DEFINE_BOOL(incremental_marking_wrappers, true,
+            "use incremental marking for marking wrappers")
 DEFINE_INT(min_progress_during_incremental_marking_finalization, 32,
            "keep finalizing incremental marking as long as we discover at "
            "least this many unmarked objects")

src/heap/heap.cc

@@ -5454,7 +5454,15 @@ void Heap::TracePossibleWrapper(JSObject* js_object) {
 }
 
 void Heap::RegisterExternallyReferencedObject(Object** object) {
-  mark_compact_collector()->RegisterExternallyReferencedObject(object);
+  HeapObject* heap_object = HeapObject::cast(*object);
+  DCHECK(Contains(heap_object));
+  if (FLAG_incremental_marking_wrappers && incremental_marking()->IsMarking()) {
+    IncrementalMarking::MarkGrey(this, heap_object);
+  } else {
+    DCHECK(mark_compact_collector()->in_use());
+    MarkBit mark_bit = ObjectMarking::MarkBitFrom(heap_object);
+    mark_compact_collector()->MarkObject(heap_object, mark_bit);
+  }
 }
 
 void Heap::TearDown() {

src/heap/incremental-marking.cc

@@ -1201,6 +1201,19 @@ intptr_t IncrementalMarking::Step(intptr_t allocated_bytes,
 
     if (state_ == MARKING) {
       bytes_processed = ProcessMarkingDeque(bytes_to_process);
+      if (FLAG_incremental_marking_wrappers &&
+          heap_->UsingEmbedderHeapTracer()) {
+        // This currently marks through all registered wrappers and does not
+        // respect bytes_to_process.
+        // TODO(hpayer): Integrate incremental marking of wrappers into
+        // bytes_to_process logic.
+        heap_->mark_compact_collector()
+            ->RegisterWrappersWithEmbedderHeapTracer();
+        heap_->mark_compact_collector()->embedder_heap_tracer()->AdvanceTracing(
+            0,
+            EmbedderHeapTracer::AdvanceTracingActions(
+                EmbedderHeapTracer::ForceCompletionAction::FORCE_COMPLETION));
+      }
       if (heap_->mark_compact_collector()->marking_deque()->IsEmpty()) {
         if (completion == FORCE_COMPLETION ||
             IsIdleMarkingDelayCounterLimitReached()) {

src/heap/mark-compact.cc

@@ -2223,14 +2223,6 @@ void MarkCompactCollector::TracePossibleWrapper(JSObject* js_object) {
   }
 }
 
-void MarkCompactCollector::RegisterExternallyReferencedObject(Object** object) {
-  DCHECK(in_use());
-  HeapObject* heap_object = HeapObject::cast(*object);
-  DCHECK(heap_->Contains(heap_object));
-  MarkBit mark_bit = ObjectMarking::MarkBitFrom(heap_object);
-  MarkObject(heap_object, mark_bit);
-}
-
 class MarkCompactCollector::ObjectStatsVisitor
     : public MarkCompactCollector::HeapObjectVisitor {
  public:

src/heap/mark-compact.h

@@ -500,8 +500,6 @@ class MarkCompactCollector {
 
   void TracePossibleWrapper(JSObject* js_object);
 
-  void RegisterExternallyReferencedObject(Object** object);
-
  private:
   class EvacuateNewSpacePageVisitor;
   class EvacuateNewSpaceVisitor;