Storage of ComputedStyle separate from LayoutObject.

third_party/WebKit/Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004-2011, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 493 matching lines @@
     virtual int maxCharacterOffset() const;
 
     // Whether or not a selection can be started in this object
     virtual bool canStartSelection() const;
 
     // -----------------------------------------------------------------------------
     // Integration with layout tree
 
     // As layoutObject() includes a branch you should avoid calling it repeatedly in hot code paths.
     // Note that if a Node has a layoutObject, it's parentNode is guaranteed to have one as well.
-    LayoutObject* layoutObject() const { return hasRareData() ? m_data.m_rareData->layoutObject() : m_data.m_layoutObject; }
+    LayoutObject* layoutObject() const
+    {
+        if (hasRareData())
+            return m_data.m_rareData->layoutObject();
+        return hasLayoutObject() ? m_data.m_layoutObject : nullptr;
+    }
     void setLayoutObject(LayoutObject* layoutObject)
     {
         if (hasRareData())
             m_data.m_rareData->setLayoutObject(layoutObject);
         else
             m_data.m_layoutObject = layoutObject;
+        if (layoutObject)
+            setFlag(HasLayoutObjectFlag);

[esprehn, 2016/08/05 21:26:26]

setFlag(static_cast<bool>(layoutObject), HasLayoutObjectFlag);

then no branch. :)

[Bugs Nash, 2016/08/12 03:55:33]

Done

+        else
+            clearFlag(HasLayoutObjectFlag);
     }
 
     // Use these two methods with caution.
     LayoutBox* layoutBox() const;
     LayoutBoxModelObject* layoutBoxModelObject() const;
 
     struct AttachContext {
         STACK_ALLOCATED();
         ComputedStyle* resolvedStyle = nullptr;
         bool performingReattach = false;
@@ skipping 194 matching lines @@
 
         HasNameOrIsEditingTextFlag = 1 << 23,
         HasWeakReferencesFlag = 1 << 24,
         V8CollectableDuringMinorGCFlag = 1 << 25,
         HasEventTargetDataFlag = 1 << 26,
         AlreadySpellCheckedFlag = 1 << 27,
 
         V0CustomElementFlag = 1 << 28,
         V0CustomElementUpgradedFlag = 1 << 29,
 
+        HasLayoutObjectFlag = 1 << 30,
+
         DefaultNodeFlags = IsFinishedParsingChildrenFlag | NeedsReattachStyleChange
     };
 
-    // 3 bits remaining.
+    // 1 bit remaining.

[esprehn, 2016/08/05 21:26:26]

thanks for fixing this :)

 
     bool getFlag(NodeFlags mask) const { return m_nodeFlags & mask; }
     void setFlag(bool f, NodeFlags mask) { m_nodeFlags = (m_nodeFlags & ~mask) | (-(int32_t)f & mask); }
     void setFlag(NodeFlags mask) { m_nodeFlags |= mask; }
     void clearFlag(NodeFlags mask) { m_nodeFlags &= ~mask; }
 
 protected:
     enum ConstructionType {
         CreateOther = DefaultNodeFlags,
         CreateText = DefaultNodeFlags | IsTextFlag,
@@ skipping 11 matching lines @@
     Node(TreeScope*, ConstructionType);
 
     virtual void didMoveToNewDocument(Document& oldDocument);
 
     void addedEventListener(const AtomicString& eventType, RegisteredEventListener&) override;
     void removedEventListener(const AtomicString& eventType, const RegisteredEventListener&) override;
     DispatchEventResult dispatchEventInternal(Event*) override;
 
     static void reattachWhitespaceSiblingsIfNeeded(Text* start);
 
+    bool hasLayoutObject() const { return getFlag(HasLayoutObjectFlag); }
     bool hasRareData() const { return getFlag(HasRareDataFlag); }
 
     NodeRareData* rareData() const;
     NodeRareData& ensureRareData();
 
     void setHasCustomStyleCallbacks() { setFlag(true, HasCustomStyleCallbacksFlag); }
 
     void setTreeScope(TreeScope* scope) { m_treeScope = scope; }
 
     // isTreeScopeInitialized() can be false
@@ skipping 38 matching lines @@
     HeapHashSet<Member<MutationObserverRegistration>>* transientMutationObserverRegistry();
 
     uint32_t m_nodeFlags;
     Member<ContainerNode> m_parentOrShadowHostNode;
     Member<TreeScope> m_treeScope;
     Member<Node> m_previous;
     Member<Node> m_next;
     // When a node has rare data we move the layoutObject into the rare data.
     union DataUnion {
         DataUnion() : m_layoutObject(nullptr) { }
+        ComputedStyle* m_computedStyle;
         // LayoutObjects are fully owned by their DOM node. See LayoutObject's
         // LIFETIME documentation section.
         LayoutObject* m_layoutObject;
         NodeRareDataBase* m_rareData;
     } m_data;
 };
 
 inline void Node::setParentOrShadowHostNode(ContainerNode* parent)
 {
     DCHECK(isMainThread());
@@ skipping 79 matching lines @@
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif // Node_h