Changeset 28884 in webkit for trunk/JavaScriptCore/kjs/JSGlobalObject.cpp

Timestamp:

Dec 20, 2007, 1:32:06 AM (17 years ago)

Author:

[email protected]

Message:

JavaScriptCore:

Reviewed by Oliver Hunt.

Optimized global access to global variables, using a symbol table.

SunSpider reports a 1.5% overall speedup, a 6.2% speedup on 3d-morph,
and a whopping 33.1% speedup on bitops-bitwise-and.

• API/JSCallbackObjectFunctions.h: Replaced calls to JSObject:: with calls to Base::, since JSObject is not always our base class. This was always a bug, but the bug is even more apparent after some of my changes.

(KJS::::staticFunctionGetter): Replaced use of getDirect with call to
getOwnPropertySlot. Global declarations are no longer stored in the
property map, so a call to getDirect is insufficient for finding
override properties.

• API/testapi.c:
• API/testapi.js: Added test for the getDirect change mentioned above.

• kjs/ExecState.cpp:
• kjs/ExecState.h: Dialed back the optimization to store a direct pointer to the localStorage buffer. One ExecState can grow the global object's localStorage without another ExecState's knowledge, so ExecState can't store a direct pointer to the localStorage buffer unless/until we invent a way to update all the relevant ExecStates.

• kjs/JSGlobalObject.cpp: Inserted the symbol table into get and put operations. (KJS::JSGlobalObject::reset): Reset the symbol table and local storage, too. Also, clear the property map here, removing the need for a separate call.

• kjs/JSVariableObject.cpp:
• kjs/JSVariableObject.h: Added support for saving localStorage and the symbol table to the back/forward cache, and restoring them.

• kjs/function.cpp: (KJS::GlobalFuncImp::callAsFunction): Renamed progNode to evalNode because it's an EvalNode, not a ProgramNode.

• kjs/lookup.h: (KJS::cacheGlobalObject): Replaced put with faster putDirect, since that's how the rest of lookup.h works. putDirect is safe here because cacheGlobalObject is only used for objects whose names are not valid identifiers.

• kjs/nodes.cpp: The good stuff!

(KJS::EvalNode::processDeclarations): Replaced hasProperty with
the new hasOwnProperty, which is slightly faster.

• kjs/object.h: Nixed clearProperties because clear() does this job now.

• kjs/property_map.cpp:
• kjs/property_map.h: More back/forward cache support.

• wtf/Vector.h: (WTF::::grow): Added fast non-branching grow function. I used it in an earlier version of this patch, even though it's not used anymore.

JavaScriptGlue:

Build fix.

• ForwardingHeaders/wtf/VectorTraits.h: Added.

WebCore:

Reviewed by Oliver Hunt.

Build support:

• ForwardingHeaders/kjs/SymbolTable.h: Added.
• ForwardingHeaders/wtf/VectorTraits.h: Added.

• bindings/js/JSDOMWindowCustom.cpp: (WebCore::JSDOMWindow::customGetOwnPropertySlot): Replaced use of getDirectLocation with getOwnPropertySlot. getDirectLocation is no longer valid, since global declarations are not stored in the property map.

(WebCore::JSDOMWindow::customPut): Replaced use of JSObject::put with
JSGlobalObject::put. JSObject::put is no longer valid, since global
declarations are not stored in the property map.

• bindings/js/kjs_window.cpp: Replaced JSObject:: calls with Base:: calls, since JSObject is not our base class. This was always a bug, but the bug is even more apparent after some of my changes.

(KJS::Window::clear): Removed call to clearProperties because
JSGlobalObject::reset takes care of that now.

• history/CachedPage.cpp:
• history/CachedPage.h: Added support for saving a symbol table and localStorage to the page cache, and restoring it.

WebKit/mac:

Reviewed by Oliver Hunt.

Build fix.

• ForwardingHeaders/kjs/SymbolTable.h: Added.
• ForwardingHeaders/wtf/VectorTraits.h: Added.

LayoutTests:

Reviewed by Oliver Hunt.

Added some tests to verify some of the changes I made while optimizing
global access to global variables.

• fast/dom/Window/resources/window-property-clearing-iframe0.html: Added.
• fast/dom/Window/resources/window-property-clearing-iframe1.html: Added.
• fast/dom/Window/window-property-clearing-expected.txt: Added.
• fast/dom/Window/window-property-clearing.html: Added.
• fast/dom/getter-on-window-object2-expected.txt: Added.
• fast/dom/getter-on-window-object2.html: Added.

Checked in failing results for these const tests. The symbol table
optimization broke const. (We didn't know this before because our only
tests used global variables.)

• fast/js/const-expected.txt:
• fast/js/kde/const-expected.txt:

• fast/js/resources/for-in-avoid-duplicates.js: Fixed a typo I noticed. Not related to this patch.

• fast/dom/Window/window-property-shadowing.html: Changed this test to use "this" instead of "window". The fact that "window" worked before, despite an overriding / shadowing var declaration, was a bug.

File:

• trunk/JavaScriptCore/kjs/JSGlobalObject.cpp (modified) (3 diffs)

trunk/JavaScriptCore/kjs/JSGlobalObject.cpp

@@ -130 +130 @@
 }
 
+bool JSGlobalObject::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
+{
+    if (symbolTableGet(propertyName, slot))
+        return true;
+    return JSVariableObject::getOwnPropertySlot(exec, propertyName, slot);
+}
+
+void JSGlobalObject::put(ExecState* exec, const Identifier& propertyName, JSValue* value, int attr)
+{
+    if (symbolTablePut(propertyName, value, attr))
+        return;
+    return JSVariableObject::put(exec, propertyName, value, attr);
+}
+
 static inline JSObject* lastInPrototypeChain(JSObject* object)
 {
@@ -140 +154 @@
 void JSGlobalObject::reset(JSValue* prototype)
 {
-    // Clear before inititalizing, to avoid marking uninitialized (dangerous) or 
-    // stale (wasteful) pointers during possible garbage collection while creating
-    // new objects below.
-
-    ExecState* exec = &d()->globalExec;
+    // Clear before inititalizing, to avoid calling mark() on stale pointers --
+    // which would be wasteful -- or uninitialized pointers -- which would be
+    // dangerous. (The allocations below may cause a GC.)
+
+    _prop.clear();
+    localStorage().clear();
+    symbolTable().clear();
 
     // Prototypes
@@ -182 +198 @@
     d()->typeErrorConstructor = 0;
     d()->URIErrorConstructor = 0;
+
+    ExecState* exec = &d()->globalExec;
 
     // Prototypes