Optimize for horizontal writing mode

Source/core/rendering/InlineBox.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 185 matching lines @@
 {
     BlockPainter::paintInlineBox(*this, paintInfo, paintOffset);
 }
 
 bool InlineBox::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, LayoutUnit /* lineTop */, LayoutUnit /*lineBottom*/)
 {
     // Hit test all phases of replaced elements atomically, as though the replaced element established its
     // own stacking context.  (See Appendix E.2, section 6.4 on inline block/table elements in the CSS2.1
     // specification.)
     LayoutPoint childPoint = accumulatedOffset;
-    if (parent()->renderer().style()->isFlippedBlocksWritingMode()) // Faster than calling containingBlock().
+    if (parent()->renderer().style()->slowIsFlippedBlocksWritingMode()) // Faster than calling containingBlock().
         childPoint = renderer().containingBlock()->flipForWritingModeForChild(&toRenderBox(renderer()), childPoint);
 
     return renderer().hitTest(request, result, locationInContainer, childPoint);
 }
 
 const RootInlineBox& InlineBox::root() const
 {
     if (m_parent)
         return m_parent->root();
     ASSERT(isRootInlineBox());
@@ skipping 84 matching lines @@
 
 void InlineBox::clearKnownToHaveNoOverflow()
 {
     m_bitfields.setKnownToHaveNoOverflow(false);
     if (parent() && parent()->knownToHaveNoOverflow())
         parent()->clearKnownToHaveNoOverflow();
 }
 
 FloatPoint InlineBox::locationIncludingFlipping()
 {
-    if (!renderer().style()->isFlippedBlocksWritingMode())
+    if (!UNLIKELY(renderer().hasFlippedBlocksWritingMode()))

[pdr., 2014/10/21 23:35:34]

Because hasFlippedBlocksWritingMode will be inlined here, can we move the
unlikely inside hasFlippedBlocksWritingMode?

         return FloatPoint(x(), y());
+
     RenderBlockFlow& block = root().block();
     if (block.style()->isHorizontalWritingMode())
         return FloatPoint(x(), block.height() - height() - y());
 
     return FloatPoint(block.width() - width() - x(), y());
 }
 
 void InlineBox::flipForWritingMode(FloatRect& rect)

[leviw_travelin_and_unemployed, 2014/10/21 23:29:59]

I wonder how much of a difference inlining these would make.

 {
-    if (!renderer().style()->isFlippedBlocksWritingMode())
+    if (!UNLIKELY(renderer().hasFlippedBlocksWritingMode()))
         return;
     root().block().flipForWritingMode(rect);
 }
 
 FloatPoint InlineBox::flipForWritingMode(const FloatPoint& point)
 {
-    if (!renderer().style()->isFlippedBlocksWritingMode())
+    if (!UNLIKELY(renderer().hasFlippedBlocksWritingMode()))
         return point;
     return root().block().flipForWritingMode(point);
 }
 
 void InlineBox::flipForWritingMode(LayoutRect& rect)
 {
-    if (!renderer().style()->isFlippedBlocksWritingMode())
+    if (!UNLIKELY(renderer().hasFlippedBlocksWritingMode()))
         return;
     root().block().flipForWritingMode(rect);
 }
 
 LayoutPoint InlineBox::flipForWritingMode(const LayoutPoint& point)
 {
-    if (!renderer().style()->isFlippedBlocksWritingMode())
+    if (!UNLIKELY(renderer().hasFlippedBlocksWritingMode()))
         return point;
     return root().block().flipForWritingMode(point);
 }
 
 } // namespace blink
 
 #ifndef NDEBUG
 
 void showTree(const blink::InlineBox* b)
 {
     if (b)
         b->showTreeForThis();
 }
 
 void showLineTree(const blink::InlineBox* b)
 {
     if (b)
         b->showLineTreeForThis();
 }
 
 #endif