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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/168335">168335</a></dd>
<dt>Author</dt> <dd>akling@apple.com</dd>
<dt>Date</dt> <dd>2014-05-05 17:53:29 -0700 (Mon, 05 May 2014)</dd>
</dl>
<h3>Log Message</h3>
<pre>Optimize GetByVal when subscript is a rope string.
<https://webkit.org/b/132590>
Use JSString::toIdentifier() in the various GetByVal implementations
to try and avoid allocating extra strings.
Added canUseFastGetOwnProperty() and wrap calls to fastGetOwnProperty()
in that, to avoid calling JSString::value() which always resolves ropes
into new strings and de-optimizes subsequent toIdentifier() calls.
My iMac says ~9% progression on Dromaeo/dom-attr.html
Reviewed by Phil Pizlo.
* dfg/DFGOperations.cpp:
* jit/JITOperations.cpp:
(JSC::getByVal):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::getByVal):
* runtime/JSCell.h:
* runtime/JSCellInlines.h:
(JSC::JSCell::fastGetOwnProperty):
(JSC::JSCell::canUseFastGetOwnProperty):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGOperationscpp">trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCorejitJITOperationscpp">trunk/Source/JavaScriptCore/jit/JITOperations.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCorellintLLIntSlowPathscpp">trunk/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoreruntimeJSCellh">trunk/Source/JavaScriptCore/runtime/JSCell.h</a></li>
<li><a href="#trunkSourceJavaScriptCoreruntimeJSCellInlinesh">trunk/Source/JavaScriptCore/runtime/JSCellInlines.h</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (168334 => 168335)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2014-05-06 00:47:33 UTC (rev 168334)
+++ trunk/Source/JavaScriptCore/ChangeLog 2014-05-06 00:53:29 UTC (rev 168335)
</span><span class="lines">@@ -1,5 +1,31 @@
</span><span class="cx"> 2014-05-05 Andreas Kling <akling@apple.com>
</span><span class="cx">
</span><ins>+ Optimize GetByVal when subscript is a rope string.
+ <https://webkit.org/b/132590>
+
+ Use JSString::toIdentifier() in the various GetByVal implementations
+ to try and avoid allocating extra strings.
+
+ Added canUseFastGetOwnProperty() and wrap calls to fastGetOwnProperty()
+ in that, to avoid calling JSString::value() which always resolves ropes
+ into new strings and de-optimizes subsequent toIdentifier() calls.
+
+ My iMac says ~9% progression on Dromaeo/dom-attr.html
+
+ Reviewed by Phil Pizlo.
+
+ * dfg/DFGOperations.cpp:
+ * jit/JITOperations.cpp:
+ (JSC::getByVal):
+ * llint/LLIntSlowPaths.cpp:
+ (JSC::LLInt::getByVal):
+ * runtime/JSCell.h:
+ * runtime/JSCellInlines.h:
+ (JSC::JSCell::fastGetOwnProperty):
+ (JSC::JSCell::canUseFastGetOwnProperty):
+
+2014-05-05 Andreas Kling <akling@apple.com>
+
</ins><span class="cx"> REGRESSION (r168256): ASSERTION FAILED: (buffer + m_length) == position loading vanityfair.com article.
</span><span class="cx"> <https://webkit.org/b/168256>
</span><span class="cx"> <rdar://problem/16816316>
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGOperationscpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp (168334 => 168335)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp 2014-05-06 00:47:33 UTC (rev 168334)
+++ trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp 2014-05-06 00:53:29 UTC (rev 168335)
</span><span class="lines">@@ -295,15 +295,18 @@
</span><span class="cx"> if (propertyAsUInt32 == propertyAsDouble)
</span><span class="cx"> return getByVal(exec, base, propertyAsUInt32);
</span><span class="cx"> } else if (property.isString()) {
</span><del>- if (JSValue result = base->fastGetOwnProperty(vm, asString(property)->value(exec)))
- return JSValue::encode(result);
</del><ins>+ Structure& structure = *base->structure(vm);
+ if (JSCell::canUseFastGetOwnProperty(structure)) {
+ if (JSValue result = base->fastGetOwnProperty(vm, structure, asString(property)->value(exec)))
+ return JSValue::encode(result);
+ }
</ins><span class="cx"> }
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> if (isName(property))
</span><span class="cx"> return JSValue::encode(baseValue.get(exec, jsCast<NameInstance*>(property.asCell())->privateName()));
</span><span class="cx">
</span><del>- Identifier ident(exec, property.toString(exec)->value(exec));
</del><ins>+ Identifier ident = property.toString(exec)->toIdentifier(exec);
</ins><span class="cx"> return JSValue::encode(baseValue.get(exec, ident));
</span><span class="cx"> }
</span><span class="cx">
</span><span class="lines">@@ -322,14 +325,17 @@
</span><span class="cx"> if (propertyAsUInt32 == propertyAsDouble)
</span><span class="cx"> return getByVal(exec, base, propertyAsUInt32);
</span><span class="cx"> } else if (property.isString()) {
</span><del>- if (JSValue result = base->fastGetOwnProperty(vm, asString(property)->value(exec)))
- return JSValue::encode(result);
</del><ins>+ Structure& structure = *base->structure(vm);
+ if (JSCell::canUseFastGetOwnProperty(structure)) {
+ if (JSValue result = base->fastGetOwnProperty(vm, structure, asString(property)->value(exec)))
+ return JSValue::encode(result);
+ }
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> if (isName(property))
</span><span class="cx"> return JSValue::encode(JSValue(base).get(exec, jsCast<NameInstance*>(property.asCell())->privateName()));
</span><span class="cx">
</span><del>- Identifier ident(exec, property.toString(exec)->value(exec));
</del><ins>+ Identifier ident = property.toString(exec)->toIdentifier(exec);
</ins><span class="cx"> return JSValue::encode(JSValue(base).get(exec, ident));
</span><span class="cx"> }
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceJavaScriptCorejitJITOperationscpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/jit/JITOperations.cpp (168334 => 168335)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/jit/JITOperations.cpp 2014-05-06 00:47:33 UTC (rev 168334)
+++ trunk/Source/JavaScriptCore/jit/JITOperations.cpp 2014-05-06 00:53:29 UTC (rev 168335)
</span><span class="lines">@@ -1420,8 +1420,12 @@
</span><span class="cx"> static JSValue getByVal(ExecState* exec, JSValue baseValue, JSValue subscript, ReturnAddressPtr returnAddress)
</span><span class="cx"> {
</span><span class="cx"> if (LIKELY(baseValue.isCell() && subscript.isString())) {
</span><del>- if (JSValue result = baseValue.asCell()->fastGetOwnProperty(exec->vm(), asString(subscript)->value(exec)))
- return result;
</del><ins>+ VM& vm = exec->vm();
+ Structure& structure = *baseValue.asCell()->structure(vm);
+ if (JSCell::canUseFastGetOwnProperty(structure)) {
+ if (JSValue result = baseValue.asCell()->fastGetOwnProperty(vm, structure, asString(subscript)->value(exec)))
+ return result;
+ }
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> if (subscript.isUInt32()) {
</span><span class="lines">@@ -1436,7 +1440,7 @@
</span><span class="cx"> if (isName(subscript))
</span><span class="cx"> return baseValue.get(exec, jsCast<NameInstance*>(subscript.asCell())->privateName());
</span><span class="cx">
</span><del>- Identifier property(exec, subscript.toString(exec)->value(exec));
</del><ins>+ Identifier property = subscript.toString(exec)->toIdentifier(exec);
</ins><span class="cx"> return baseValue.get(exec, property);
</span><span class="cx"> }
</span><span class="cx">
</span><span class="lines">@@ -1518,7 +1522,7 @@
</span><span class="cx"> } else if (isName(subscript))
</span><span class="cx"> result = baseValue.get(exec, jsCast<NameInstance*>(subscript.asCell())->privateName());
</span><span class="cx"> else {
</span><del>- Identifier property(exec, subscript.toString(exec)->value(exec));
</del><ins>+ Identifier property = subscript.toString(exec)->toIdentifier(exec);
</ins><span class="cx"> result = baseValue.get(exec, property);
</span><span class="cx"> }
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceJavaScriptCorellintLLIntSlowPathscpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp (168334 => 168335)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp 2014-05-06 00:47:33 UTC (rev 168334)
+++ trunk/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp 2014-05-06 00:53:29 UTC (rev 168335)
</span><span class="lines">@@ -715,8 +715,12 @@
</span><span class="cx"> inline JSValue getByVal(ExecState* exec, JSValue baseValue, JSValue subscript)
</span><span class="cx"> {
</span><span class="cx"> if (LIKELY(baseValue.isCell() && subscript.isString())) {
</span><del>- if (JSValue result = baseValue.asCell()->fastGetOwnProperty(exec->vm(), asString(subscript)->value(exec)))
- return result;
</del><ins>+ VM& vm = exec->vm();
+ Structure& structure = *baseValue.asCell()->structure(vm);
+ if (JSCell::canUseFastGetOwnProperty(structure)) {
+ if (JSValue result = baseValue.asCell()->fastGetOwnProperty(vm, structure, asString(subscript)->value(exec)))
+ return result;
+ }
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> if (subscript.isUInt32()) {
</span><span class="lines">@@ -730,7 +734,7 @@
</span><span class="cx"> if (isName(subscript))
</span><span class="cx"> return baseValue.get(exec, jsCast<NameInstance*>(subscript.asCell())->privateName());
</span><span class="cx">
</span><del>- Identifier property(exec, subscript.toString(exec)->value(exec));
</del><ins>+ Identifier property = subscript.toString(exec)->toIdentifier(exec);
</ins><span class="cx"> return baseValue.get(exec, property);
</span><span class="cx"> }
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreruntimeJSCellh"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/runtime/JSCell.h (168334 => 168335)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/runtime/JSCell.h 2014-05-06 00:47:33 UTC (rev 168334)
+++ trunk/Source/JavaScriptCore/runtime/JSCell.h 2014-05-06 00:53:29 UTC (rev 168335)
</span><span class="lines">@@ -144,7 +144,8 @@
</span><span class="cx"> void zap() { *reinterpret_cast<uintptr_t**>(this) = 0; }
</span><span class="cx"> bool isZapped() const { return !*reinterpret_cast<uintptr_t* const*>(this); }
</span><span class="cx">
</span><del>- JSValue fastGetOwnProperty(VM&, const String&);
</del><ins>+ static bool canUseFastGetOwnProperty(const Structure&);
+ JSValue fastGetOwnProperty(VM&, Structure&, const String&);
</ins><span class="cx">
</span><span class="cx"> enum GCData : uint8_t {
</span><span class="cx"> Marked = 0,
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreruntimeJSCellInlinesh"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/runtime/JSCellInlines.h (168334 => 168335)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/runtime/JSCellInlines.h 2014-05-06 00:47:33 UTC (rev 168334)
+++ trunk/Source/JavaScriptCore/runtime/JSCellInlines.h 2014-05-06 00:53:29 UTC (rev 168335)
</span><span class="lines">@@ -213,19 +213,22 @@
</span><span class="cx"> // identifier. The first time we perform a property access with a given string, try
</span><span class="cx"> // performing the property map lookup without forming an identifier. We detect this
</span><span class="cx"> // case by checking whether the hash has yet been set for this string.
</span><del>-ALWAYS_INLINE JSValue JSCell::fastGetOwnProperty(VM& vm, const String& name)
</del><ins>+ALWAYS_INLINE JSValue JSCell::fastGetOwnProperty(VM& vm, Structure& structure, const String& name)
</ins><span class="cx"> {
</span><del>- Structure& structure = *this->structure(vm);
- if (!structure.typeInfo().overridesGetOwnPropertySlot() && !structure.hasGetterSetterProperties()) {
- PropertyOffset offset = name.impl()->hasHash()
- ? structure.get(vm, Identifier(&vm, name))
- : structure.get(vm, name);
- if (offset != invalidOffset)
- return asObject(this)->locationForOffset(offset)->get();
- }
</del><ins>+ ASSERT(canUseFastGetOwnProperty(vm));
+ PropertyOffset offset = name.impl()->hasHash()
+ ? structure.get(vm, Identifier(&vm, name))
+ : structure.get(vm, name);
+ if (offset != invalidOffset)
+ return asObject(this)->locationForOffset(offset)->get();
</ins><span class="cx"> return JSValue();
</span><span class="cx"> }
</span><span class="cx">
</span><ins>+inline bool JSCell::canUseFastGetOwnProperty(const Structure& structure)
+{
+ return !structure.hasGetterSetterProperties() && !structure.typeInfo().overridesGetOwnPropertySlot();
+}
+
</ins><span class="cx"> inline bool JSCell::toBoolean(ExecState* exec) const
</span><span class="cx"> {
</span><span class="cx"> if (isString())
</span></span></pre>
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