Extend Handle API with MarkIndependent.

src/heap.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 753 matching lines @@
   } else {
     tracer_ = tracer;
     Scavenge();
     tracer_ = NULL;
 
     UpdateSurvivalRateTrend(start_new_space_size);
   }
 
   isolate_->counters()->objs_since_last_young()->Set(0);
 
-  if (collector == MARK_COMPACTOR) {
-    DisableAssertNoAllocation allow_allocation;
+  { DisableAssertNoAllocation allow_allocation;
     GCTracer::Scope scope(tracer, GCTracer::Scope::EXTERNAL);
     next_gc_likely_to_collect_more =
         isolate_->global_handles()->PostGarbageCollectionProcessing();
   }
 
   // Update relocatables.
   Relocatable::PostGarbageCollectionProcessing();
 
   if (collector == MARK_COMPACTOR) {
     // Register the amount of external allocated memory.
@@ skipping 142 matching lines @@
   if (new_space_.Capacity() < new_space_.MaximumCapacity() &&
       survived_since_last_expansion_ > new_space_.Capacity()) {
     // Grow the size of new space if there is room to grow and enough
     // data has survived scavenge since the last expansion.
     new_space_.Grow();
     survived_since_last_expansion_ = 0;
   }
 }
 
 
+static bool IsUnscavengedHeapObject(Heap* heap, Object** p) {
+  return heap->InNewSpace(*p) &&
+      !HeapObject::cast(*p)->map_word().IsForwardingAddress();
+}
+
+
 void Heap::Scavenge() {
 #ifdef DEBUG
   if (FLAG_enable_slow_asserts) VerifyNonPointerSpacePointers();
 #endif
 
   gc_state_ = SCAVENGE;
 
   SwitchScavengingVisitorsTableIfProfilingWasEnabled();
 
   Page::FlipMeaningOfInvalidatedWatermarkFlag(this);
@@ skipping 74 matching lines @@
           reinterpret_cast<Address>(cell) +
           (JSGlobalPropertyCell::kValueOffset - kHeapObjectTag);
       scavenge_visitor.VisitPointer(reinterpret_cast<Object**>(value_address));
     }
   }
 
   // Scavenge object reachable from the global contexts list directly.
   scavenge_visitor.VisitPointer(BitCast<Object**>(&global_contexts_list_));
 
   new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+  isolate_->global_handles()->IdentifyWeakIndependentHandles(
+      &IsUnscavengedHeapObject);
+  isolate_->global_handles()->IterateWeakIndependentRoots(&scavenge_visitor);
+  new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+
 
   UpdateNewSpaceReferencesInExternalStringTable(
       &UpdateNewSpaceReferenceInExternalStringTableEntry);
 
   LiveObjectList::UpdateReferencesForScavengeGC();
   isolate()->runtime_profiler()->UpdateSamplesAfterScavenge();
 
   ASSERT(new_space_front == new_space_.top());
 
   is_safe_to_read_maps_ = true;
@@ skipping 3443 matching lines @@
 
 void Heap::IterateRoots(ObjectVisitor* v, VisitMode mode) {
   IterateStrongRoots(v, mode);
   IterateWeakRoots(v, mode);
 }
 
 
 void Heap::IterateWeakRoots(ObjectVisitor* v, VisitMode mode) {
   v->VisitPointer(reinterpret_cast<Object**>(&roots_[kSymbolTableRootIndex]));
   v->Synchronize("symbol_table");
-  if (mode != VISIT_ALL_IN_SCAVENGE) {
+  if (mode != VISIT_ALL_IN_SCAVENGE &&
+      mode != VISIT_ALL_IN_SWEEP_NEWSPACE) {
     // Scavenge collections have special processing for this.
     external_string_table_.Iterate(v);
   }
   v->Synchronize("external_string_table");
 }
 
 
 void Heap::IterateStrongRoots(ObjectVisitor* v, VisitMode mode) {
   v->VisitPointers(&roots_[0], &roots_[kStrongRootListLength]);
   v->Synchronize("strong_root_list");
@@ skipping 15 matching lines @@
   isolate_->compilation_cache()->Iterate(v);
   v->Synchronize("compilationcache");
 
   // Iterate over local handles in handle scopes.
   isolate_->handle_scope_implementer()->Iterate(v);
   v->Synchronize("handlescope");
 
   // Iterate over the builtin code objects and code stubs in the
   // heap. Note that it is not necessary to iterate over code objects
   // on scavenge collections.
-  if (mode != VISIT_ALL_IN_SCAVENGE) {
+  if (mode != VISIT_ALL_IN_SCAVENGE &&
+      mode != VISIT_ALL_IN_SWEEP_NEWSPACE) {
     isolate_->builtins()->IterateBuiltins(v);
   }
   v->Synchronize("builtins");
 
   // Iterate over global handles.
-  if (mode == VISIT_ONLY_STRONG) {
-    isolate_->global_handles()->IterateStrongRoots(v);
-  } else {
-    isolate_->global_handles()->IterateAllRoots(v);
+  switch (mode) {
+    case VISIT_ONLY_STRONG:
+      isolate_->global_handles()->IterateStrongRoots(v);
+      break;
+    case VISIT_ALL_IN_SCAVENGE:
+      isolate_->global_handles()->IterateStrongAndDependentRoots(v);
+      break;
+    case VISIT_ALL_IN_SWEEP_NEWSPACE:
+    case VISIT_ALL:
+      isolate_->global_handles()->IterateAllRoots(v);
+      break;
   }
   v->Synchronize("globalhandles");
 
   // Iterate over pointers being held by inactive threads.
   isolate_->thread_manager()->Iterate(v);
   v->Synchronize("threadmanager");
 
   // Iterate over the pointers the Serialization/Deserialization code is
   // holding.
   // During garbage collection this keeps the partial snapshot cache alive.
@@ skipping 1332 matching lines @@
 }
 
 
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 } }  // namespace v8::internal