Supporting AllocationSiteInfo for Nested arrays

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 1278 matching lines @@
 void JSObject::ValidateElements() {
 #if DEBUG
   if (FLAG_enable_slow_asserts) {
     ElementsAccessor* accessor = GetElementsAccessor();
     accessor->Validate(this);
   }
 #endif
 }
 
 
+bool JSObject::ShouldTrackAllocationInfo() {
+  if (map()->CanTrackAllocationSite()) {
+    if (!IsJSArray()) {
+      return true;
+    }
+
+    return AllocationSiteInfo::GetMode(GetElementsKind()) ==
+        TRACK_ALLOCATION_SITE;
+  }
+  return false;
+}
+
+
+// Heuristic: We only need to create allocation site info if the boilerplate
+// elements kind is the initial elements kind.
+AllocationSiteMode AllocationSiteInfo::GetMode(
+    ElementsKind boilerplate_elements_kind) {
+  if (FLAG_track_allocation_sites &&
+      IsFastSmiElementsKind(boilerplate_elements_kind)) {
+    return TRACK_ALLOCATION_SITE;
+  }
+
+  return DONT_TRACK_ALLOCATION_SITE;
+}
+
+
+AllocationSiteMode AllocationSiteInfo::GetMode(ElementsKind from,
+                                               ElementsKind to) {
+  if (FLAG_track_allocation_sites &&
+      IsFastSmiElementsKind(from) &&
+      (IsFastObjectElementsKind(to) || IsFastDoubleElementsKind(to))) {
+    return TRACK_ALLOCATION_SITE;
+  }
+
+  return DONT_TRACK_ALLOCATION_SITE;
+}
+
+
 MaybeObject* JSObject::EnsureCanContainHeapObjectElements() {
   ValidateElements();
   ElementsKind elements_kind = map()->elements_kind();
   if (!IsFastObjectElementsKind(elements_kind)) {
     if (IsFastHoleyElementsKind(elements_kind)) {
       return TransitionElementsKind(FAST_HOLEY_ELEMENTS);
     } else {
       return TransitionElementsKind(FAST_ELEMENTS);
     }
   }
@@ skipping 4701 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_