Reduce Node object size from 72 byte to 64 byte
https://bugs.webkit.org/show_bug.cgi?id=88528
Reviewed by Ryosuke Niwa.
.:
Added a symbol for callRemovedLastRef().
* Source/autotools/symbols.filter:
Source/WebCore:
This patch removes all virtual methods from TreeShared.h,
by which we can remove a virtual method table pointer (8 byte
in a 64bit architechture) from each Node object. Consequently,
this patch reduces the Node object size from 72 byte to 64 byte.
e.g. The HTML spec (http://www.whatwg.org/specs/web-apps/current-work/)
contains 325640 Node objects. Thus this patch saves 325640 * 8 byte = 2.6 MB.
e.g. sizeof(Element) is reduced from 104 byte to 96 byte.
- In multiple inheritance, a virtual method table pointer is allocated
for each base class that has virtual methods. For example, for
'class A : public B, C {};' where B and C have virtual methods,
two virtual method table pointers are allocated for each A object.
In this patch, A = Node, B = EventTarget, and C = TreeShared.
By removing the virtual methods from TreeShared, we can save the virtual
method table pointer for TreeShared. 8 byte saving.
- Node and SVGElementInstance are the only classes that inherit TreeShared.
- This patch removes virtual TreeShared::removeLastRef() and implements
virtual Node::removeLastRef() and virtual SVGElementInstance::removeLastRef().
Node::removeLastRef() calls 'delete this' for 'this' of type Node*,
and SVGElementInstance::removeLastRef() calls 'delete this' for 'this' of type
SVGElementInstance*.
- This patch removes the virtual destructor of TreeShared. This removal is safe
because (1) no one calls 'delete this' for 'this' of type TreeShared*,
and (2) both Node and SVGElementInstance have virtual destructor.
No change in behavior. Confirm no regression in existing tests.
* dom/ContainerNode.cpp:
(WebCore::callRemovedLastRef):
(WebCore):
* dom/Node.h:
(WebCore::Node::removedLastRef):
* platform/TreeShared.h:
(WebCore):
(TreeShared):
(WebCore::TreeShared::deref):
* svg/SVGElementInstance.cpp:
(WebCore::callRemovedLastRef):
(WebCore):
* svg/SVGElementInstance.h:
(WebCore::SVGElementInstance::removedLastRef):
* WebCore.order: Added a symbol for callRemovedLastRef().
* WebCore.exp.in: Ditto.
Source/WebKit/mac:
Added a symbol for callRemovedLastRef().
* WebKit.order:
Source/WebKit2:
Added a symbol for callRemovedLastRef().
* mac/WebKit2.order:
* win/WebKit2.def:
* win/WebKit2CFLite.def:
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@119802 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/ChangeLog b/ChangeLog
index ac7bfcf..14f7302 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2012-06-07 Kentaro Hara <haraken@chromium.org>
+
+ Reduce Node object size from 72 byte to 64 byte
+ https://bugs.webkit.org/show_bug.cgi?id=88528
+
+ Reviewed by Ryosuke Niwa.
+
+ Added a symbol for callRemovedLastRef().
+
+ * Source/autotools/symbols.filter:
+
2012-06-07 Patrick Gansterer <paroga@webkit.org>
Build fix for WinCE after r113570.
