// Copyright 2013 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef V8_ALLOCATION_SITE_SCOPES_H_ #define V8_ALLOCATION_SITE_SCOPES_H_ #include "src/handles.h" #include "src/objects.h" #include "src/objects/map.h" namespace v8 { namespace internal { // AllocationSiteContext is the base class for walking and copying a nested // boilerplate with AllocationSite and AllocationMemento support. class AllocationSiteContext { public: explicit AllocationSiteContext(Isolate* isolate) { isolate_ = isolate; } Handle<AllocationSite> top() { return top_; } Handle<AllocationSite> current() { return current_; } bool ShouldCreateMemento(Handle<JSObject> object) { return false; } Isolate* isolate() { return isolate_; } protected: void update_current_site(AllocationSite* site) { *(current_.location()) = site; } void InitializeTraversal(Handle<AllocationSite> site) { top_ = site; // {current_} is updated in place to not create unnecessary Handles, hence // we initially need a separate handle. current_ = Handle<AllocationSite>::New(*top_, isolate()); } private: Isolate* isolate_; Handle<AllocationSite> top_; Handle<AllocationSite> current_; }; // AllocationSiteUsageContext aids in the creation of AllocationMementos placed // behind some/all components of a copied object literal. class AllocationSiteUsageContext : public AllocationSiteContext { public: AllocationSiteUsageContext(Isolate* isolate, Handle<AllocationSite> site, bool activated) : AllocationSiteContext(isolate), top_site_(site), activated_(activated) { } inline Handle<AllocationSite> EnterNewScope() { if (top().is_null()) { InitializeTraversal(top_site_); } else { // Advance current site Object* nested_site = current()->nested_site(); // Something is wrong if we advance to the end of the list here. update_current_site(AllocationSite::cast(nested_site)); } return Handle<AllocationSite>(*current(), isolate()); } inline void ExitScope(Handle<AllocationSite> scope_site, Handle<JSObject> object) { // This assert ensures that we are pointing at the right sub-object in a // recursive walk of a nested literal. DCHECK(object.is_null() || *object == scope_site->boilerplate()); } bool ShouldCreateMemento(Handle<JSObject> object) { if (activated_ && AllocationSite::CanTrack(object->map()->instance_type())) { if (FLAG_allocation_site_pretenuring || AllocationSite::ShouldTrack(object->GetElementsKind())) { if (FLAG_trace_creation_allocation_sites) { PrintF("*** Creating Memento for %s %p\n", object->IsJSArray() ? "JSArray" : "JSObject", static_cast<void*>(*object)); } return true; } } return false; } static const bool kCopying = true; private: Handle<AllocationSite> top_site_; bool activated_; }; } // namespace internal } // namespace v8 #endif // V8_ALLOCATION_SITE_SCOPES_H_