DO NOT LAND - Code for debugging excess style recalcs

Source/core/dom/Node.cpp

 /*
  * 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, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 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
@@ skipping 78 matching lines @@
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/Partitions.h"
 #include "wtf/HashSet.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefCountedLeakCounter.h"
 #include "wtf/UnusedParam.h"
 #include "wtf/Vector.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/StringBuilder.h"
 
+#include "base/debug/stack_trace.h"
+#include "bindings/v8/ScriptCallStackFactory.h"
+
 using namespace std;
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 void* Node::operator new(size_t size)
 {
     ASSERT(isMainThread());
     return partitionAlloc(Partitions::getObjectModelPartition(), size);
@@ skipping 583 matching lines @@
 }
 
 void Node::markAncestorsWithChildNeedsDistributionRecalc()
 {
     for (Node* node = this; node && !node->childNeedsDistributionRecalc(); node = node->parentOrShadowHostNode())
         node->setChildNeedsDistributionRecalc();
     if (document().childNeedsDistributionRecalc())
         document().scheduleStyleRecalc();
 }
 
+size_t subtreeSize(Node* rootNode)
+{
+    size_t subtreeSize = 1;
+    Node* currentNode = rootNode;
+    while ((currentNode = NodeTraversal::next(*currentNode, rootNode)))
+        subtreeSize++;
+    return subtreeSize;
+}
+
+static void printJSStackTrace()
+{
+    RefPtr<ScriptCallStack> stack = createScriptCallStack(10);
+    if (!stack) {
+        // The last function in the JS stack always seems to be an empty string?
+        // to compensate, print an extra \n here.
+        printf("Not JS triggered.\n\n");
+        return;
+    }
+    printf("JS Stack:\n");
+    for (size_t i = 0; i < stack->size(); i++)
+        printf("%s\n", stack->at(i).functionName().ascii().data());
+    printf("\n");
+}
+
 inline void Node::setStyleChange(StyleChangeType changeType)
 {
+    static const size_t kMinLoggedSize = 100;
+    if (changeType >= SubtreeStyleChange) {
+        size_t nodeCount = subtreeSize(this);
+        if (nodeCount >= kMinLoggedSize) {
+            printf("\n\nINVALIDATED style on tree of %zu nodes (threshold: %zu)\n", nodeCount, kMinLoggedSize);
+            printf("Root: %s\n\n", debugName().ascii().data());
+            printJSStackTrace();
+            printf("C++ Stack:\n");
+            base::debug::StackTrace().Print();
+        }
+    }
     m_nodeFlags = (m_nodeFlags & ~StyleChangeMask) | changeType;
 }
 
 void Node::markAncestorsWithChildNeedsStyleRecalc()
 {
     for (ContainerNode* p = parentOrShadowHostNode(); p && !p->childNeedsStyleRecalc(); p = p->parentOrShadowHostNode())
         p->setChildNeedsStyleRecalc();
 
     if (document().needsStyleRecalc() || document().childNeedsStyleRecalc())
         document().scheduleStyleRecalc();
@@ skipping 1957 matching lines @@
         node->showTreeForThis();
 }
 
 void showNodePath(const WebCore::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif