Changeset 197308 in webkit for trunk/Source/JavaScriptCore/runtime

Timestamp:

Feb 28, 2016, 9:26:05 PM (9 years ago)

Author:

[email protected]

Message:

Make JSFunction.name allocation fully lazy.
<​https://webkit.org/b/154806>

Reviewed by Saam Barati.

We were reifying the "name" field on functions lazily, but created the string
value itself up front. This patch gets rid of the up-front allocation,
saving us a JSString allocation per function in most cases.

• builtins/BuiltinExecutables.cpp:

(JSC::createExecutableInternal):

• bytecode/UnlinkedFunctionExecutable.cpp:

(JSC::UnlinkedFunctionExecutable::visitChildren):

• bytecode/UnlinkedFunctionExecutable.h:
• runtime/CodeCache.cpp:

(JSC::CodeCache::getFunctionExecutableFromGlobalCode):

• runtime/Executable.h:
• runtime/JSFunction.cpp:

(JSC::JSFunction::reifyName):

Location:

trunk/Source/JavaScriptCore/runtime

Files:

• CodeCache.cpp (modified) (2 diffs)
• Executable.h (modified) (1 diff)
• JSFunction.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/runtime/CodeCache.cpp

@@ -188 +188 @@
         return nullptr;
     
+    metadata->overrideName(name);
     metadata->setEndPosition(positionBeforeLastNewline);
     // The Function constructor only has access to global variables, so no variables will be under TDZ.
@@ -193 +194 @@
     UnlinkedFunctionExecutable* functionExecutable = UnlinkedFunctionExecutable::create(&vm, source, metadata, UnlinkedNormalFunction, ConstructAbility::CanConstruct, emptyTDZVariables, DerivedContextType::None);
 
-    functionExecutable->m_nameValue.set(vm, functionExecutable, jsString(&vm, name.string()));
-
     m_sourceCode.addCache(key, SourceCodeValue(vm, functionExecutable, m_sourceCode.age()));
     return functionExecutable;

trunk/Source/JavaScriptCore/runtime/Executable.h

@@ -668 +668 @@
     const Identifier& name() { return m_unlinkedExecutable->name(); }
     const Identifier& inferredName() { return m_unlinkedExecutable->inferredName(); }
-    JSString* nameValue() const { return m_unlinkedExecutable->nameValue(); }
     size_t parameterCount() const { return m_unlinkedExecutable->parameterCount(); } // Excluding 'this'!
     SourceParseMode parseMode() const { return m_unlinkedExecutable->parseMode(); }

trunk/Source/JavaScriptCore/runtime/JSFunction.cpp

@@ -590 +590 @@
     ASSERT(!hasReifiedName());
     ASSERT(!isHostFunction());
-    JSValue initialValue = jsExecutable()->nameValue();
     unsigned initialAttributes = DontEnum | ReadOnly;
     const Identifier& identifier = exec->propertyNames().name;
-    putDirect(vm, identifier, initialValue, initialAttributes);
+    putDirect(vm, identifier, jsString(exec, jsExecutable()->name().string()), initialAttributes);
 
     rareData->setHasReifiedName();