AllocationSites for all literals

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 26cb3c53dc92a5008151669e849a998710f4e107..0a8f57b9e223819c6bf2f68670ea6fc39d522e97 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -28,6 +28,7 @@
 #include "v8.h"
 
 #include "accessors.h"
+#include "allocation-site-scopes.h"
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
@@ -5615,6 +5616,14 @@ MUST_USE_RESULT MaybeObject* JSObject::SetObserved(Isolate* isolate) {
 }
 
 
+Handle<JSObject> JSObject::Copy(Handle<JSObject> object,
+                                Handle<AllocationSite> site) {
+  Isolate* isolate = object->GetIsolate();
+  CALL_HEAP_FUNCTION(isolate,
+                     isolate->heap()->CopyJSObject(*object, *site), JSObject);
+}
+
+
 Handle<JSObject> JSObject::Copy(Handle<JSObject> object) {
   Isolate* isolate = object->GetIsolate();
   CALL_HEAP_FUNCTION(isolate,
@@ -5624,45 +5633,93 @@ Handle<JSObject> JSObject::Copy(Handle<JSObject> object) {
 
 class JSObjectWalkVisitor {
  public:
-  explicit JSObjectWalkVisitor() {}
+  explicit JSObjectWalkVisitor(AllocationSiteContext* site_context) :
+      site_context_(site_context) {}
   virtual ~JSObjectWalkVisitor() {}
 
   Handle<JSObject> Visit(Handle<JSObject> object) {
     return StructureWalk(object);
   }
 
-  // Returns true if the visitor is a copying visitor.
   virtual bool is_copying() = 0;
 
  protected:
   Handle<JSObject> StructureWalk(Handle<JSObject> object);
 
-  // The returned handle should point to a new object if the visitor is a
-  // copying visitor, otherwise it should be the same as the input object.
+  // The returned handle will be used for the object in all subsequent usages.
+  // This allows VisitObject to make a copy of the object if desired.
   virtual Handle<JSObject> VisitObject(Handle<JSObject> object) = 0;
-
-  // The returned handle should point to a new value if the visitor is a
-  // copying visitor, otherwise it should be the same as the input value.
   virtual Handle<JSObject> VisitElementOrProperty(Handle<JSObject> object,
                                                   Handle<JSObject> value) = 0;
+
+  AllocationSiteContext* site_context() { return site_context_; }
+
+ private:
+  AllocationSiteContext* site_context_;
 };
 
 
 class JSObjectCopyVisitor: public JSObjectWalkVisitor {
  public:
-  explicit JSObjectCopyVisitor() {}
+  explicit JSObjectCopyVisitor(AllocationSiteContext* site_context)
+      : JSObjectWalkVisitor(site_context) {}
 
   virtual bool is_copying() V8_OVERRIDE { return true; }
 
- protected:
+  // The returned handle will be used for the object in all
+  // subsequent usages. This allows VisitObject to make a copy
+  // of the object if desired.
   virtual Handle<JSObject> VisitObject(Handle<JSObject> object) V8_OVERRIDE {
-    return JSObject::Copy(object);
+    // Only create a memento if
+    // 1) we have a JSArray, and
+    // 2) the elements kind is palatable
+    // 3) allow_mementos is true
+    Handle<JSObject> copy;
+    if (site_context()->activated() &&
+        AllocationSite::CanTrack(object->map()->instance_type()) &&
+        AllocationSite::GetMode(object->GetElementsKind()) ==
+        TRACK_ALLOCATION_SITE) {
+      copy = JSObject::Copy(object, site_context()->current());
+    } else {
+      copy = JSObject::Copy(object);
+    }
+
+    return copy;
   }
 
   virtual Handle<JSObject> VisitElementOrProperty(
       Handle<JSObject> object,
       Handle<JSObject> value) V8_OVERRIDE {
-    return StructureWalk(value);
+    Handle<AllocationSite> current_site = site_context()->EnterNewScope();
+    Handle<JSObject> copy_of_value = StructureWalk(value);
+    site_context()->ExitScope(current_site, value);
+    return copy_of_value;
+  }
+};
+
+
+class JSObjectCreateAllocationSitesVisitor: public JSObjectWalkVisitor {
+ public:
+  explicit JSObjectCreateAllocationSitesVisitor(
+      AllocationSiteContext* site_context)
+      : JSObjectWalkVisitor(site_context) {}
+
+  virtual bool is_copying() V8_OVERRIDE { return false; }
+
+  // The returned handle will be used for the object in all
+  // subsequent usages. This allows VisitObject to make a copy
+  // of the object if desired.
+  virtual Handle<JSObject> VisitObject(Handle<JSObject> object) V8_OVERRIDE {
+    return object;
+  }
+
+  virtual Handle<JSObject> VisitElementOrProperty(
+      Handle<JSObject> object,
+      Handle<JSObject> value) V8_OVERRIDE {
+    Handle<AllocationSite> current_site = site_context()->EnterNewScope();
+    value = StructureWalk(value);
+    site_context()->ExitScope(current_site, value);
+    return value;
   }
 };
 
@@ -5809,8 +5866,18 @@ Handle<JSObject> JSObjectWalkVisitor::StructureWalk(Handle<JSObject> object) {
 }
 
 
-Handle<JSObject> JSObject::DeepCopy(Handle<JSObject> object) {
-  JSObjectCopyVisitor v;
+Handle<JSObject> JSObject::DeepWalk(Handle<JSObject> object,
+                                    AllocationSiteContext* site_context) {
+  JSObjectCreateAllocationSitesVisitor v(site_context);
+  Handle<JSObject> copy = v.Visit(object);
+  ASSERT(!v.is_copying() && copy.is_identical_to(object));
+  return copy;
+}
+
+
+Handle<JSObject> JSObject::DeepCopy(Handle<JSObject> object,
+                                    AllocationSiteContext* site_context) {
+  JSObjectCopyVisitor v(site_context);
   Handle<JSObject> copy = v.Visit(object);
   ASSERT(v.is_copying() && !copy.is_identical_to(object));
   return copy;
@@ -12573,6 +12640,20 @@ void JSObject::TransitionElementsKind(Handle<JSObject> object,
 }
 
 
+bool AllocationSite::IsNestedSite() {
+  ASSERT(FLAG_trace_track_allocation_sites);
+  Object* current = GetHeap()->allocation_sites_list();
+  while (current != NULL && current->IsAllocationSite()) {
+    AllocationSite* current_site = AllocationSite::cast(current);
+    if (current_site->nested_site() == this) {
+      return true;
+    }
+    current = current_site->weak_next();
+  }
+  return false;
+}
+
+
 MaybeObject* JSObject::UpdateAllocationSite(ElementsKind to_kind) {
   if (!FLAG_track_allocation_sites || !IsJSArray()) {
     return this;
@@ -12585,7 +12666,8 @@ MaybeObject* JSObject::UpdateAllocationSite(ElementsKind to_kind) {
 
   // Walk through to the Allocation Site
   AllocationSite* site = memento->GetAllocationSite();
-  if (site->IsLiteralSite()) {
+  if (site->SitePointsToLiteral() &&
+      site->transition_info()->IsJSArray()) {
     JSArray* transition_info = JSArray::cast(site->transition_info());
     ElementsKind kind = transition_info->GetElementsKind();
     // if kind is holey ensure that to_kind is as well.
@@ -12599,9 +12681,11 @@ MaybeObject* JSObject::UpdateAllocationSite(ElementsKind to_kind) {
       CHECK(transition_info->length()->ToArrayIndex(&length));
       if (length <= AllocationSite::kMaximumArrayBytesToPretransition) {
         if (FLAG_trace_track_allocation_sites) {
+          bool is_nested = site->IsNestedSite();
           PrintF(
-              "AllocationSite: JSArray %p boilerplate updated %s->%s\n",
+              "AllocationSite: JSArray %p boilerplate %s updated %s->%s\n",
               reinterpret_cast<void*>(this),
+              is_nested ? "(nested)" : "",
               ElementsKindToString(kind),
               ElementsKindToString(to_kind));
         }