Make maps in monomorphic IC stubs weak.

src/objects-inl.h

 // Copyright 2012 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 4753 matching lines @@
 
 
 void Code::set_marked_for_deoptimization(bool flag) {
   ASSERT(kind() == OPTIMIZED_FUNCTION);
   int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
   int updated = MarkedForDeoptimizationField::update(previous, flag);
   WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
 }
 
 
+bool Code::is_weak_stub() {
+  return CanBeWeakStub() && WeakStubField::decode(
+      READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
+}
+
+
+void Code::mark_as_weak_stub() {
+  ASSERT(CanBeWeakStub());
+  int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
+  int updated = WeakStubField::update(previous, true);
+  WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
+}
+
+
+bool Code::is_invalidated_weak_stub() {
+  return is_weak_stub() && InvalidatedWeakStubField::decode(
+      READ_UINT32_FIELD(this, kKindSpecificFlags1Offset));
+}
+
+
+void Code::mark_as_invalidated_weak_stub() {
+  ASSERT(is_inline_cache_stub());
+  int previous = READ_UINT32_FIELD(this, kKindSpecificFlags1Offset);
+  int updated = InvalidatedWeakStubField::update(previous, true);
+  WRITE_UINT32_FIELD(this, kKindSpecificFlags1Offset, updated);
+}
+
+
 bool Code::is_inline_cache_stub() {
   Kind kind = this->kind();
   switch (kind) {
 #define CASE(name) case name: return true;
     IC_KIND_LIST(CASE)
 #undef CASE
     default: return false;
   }
 }
 
@@ skipping 123 matching lines @@
   }
  private:
   static const int kMaxCount = 4;
   int count_;
   Handle<Map> find_[kMaxCount];
   Handle<Object> replace_[kMaxCount];
   friend class Code;
 };
 
 
+bool Code::IsWeakObjectInIC(Object* object) {
+  return object->IsMap() && Map::cast(object)->CanTransition() &&
+         FLAG_collect_maps &&
+         FLAG_weak_embedded_maps_in_ic;
+}
+
+
 Object* Map::prototype() {
   return READ_FIELD(this, kPrototypeOffset);
 }
 
 
 void Map::set_prototype(Object* value, WriteBarrierMode mode) {
   ASSERT(value->IsNull() || value->IsJSReceiver());
   WRITE_FIELD(this, kPrototypeOffset, value);
   CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kPrototypeOffset, value, mode);
 }
@@ skipping 2126 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_