Changeset 222143 in webkit for trunk/Source/JavaScriptCore/runtime/JSGlobalObject.h

Timestamp:

Sep 18, 2017, 5:47:26 AM (8 years ago)

Author:

Yusuke Suzuki

Message:

[DFG] Remove ToThis more aggressively
​https://bugs.webkit.org/show_bug.cgi?id=177056

Reviewed by Saam Barati.

JSTests:

• stress/generator-with-this-strict.js: Added.

(shouldBe):
(generator):
(target):

• stress/generator-with-this.js: Added.

(shouldBe):
(generator):
(target):

Source/JavaScriptCore:

The variation of toThis() implementation is limited. So, we attempts to implement common toThis operation in AI.
We move scope related toThis to JSScope::toThis. And AI investigates proven value/structure's toThis methods
and attempts to fold/convert to efficient nodes.

We introduces GetGlobalThis, which just loads globalThis from semantic origin's globalObject. Using this,
we can implement JSScope::toThis in DFG. This can avoid costly toThis indirect function pointer call.

Currently, we just emit GetGlobalThis if necessary. We can further convert it to constant if we can put
watchpoint to JSGlobalObject's globalThis change. But we leave it for a future patch for now.

This removes GetGlobalThis from ES6 generators in common cases.

spread-generator.es6 303.1550+-9.5037 290.9337+-8.3487 might be 1.0420x faster

• dfg/DFGAbstractInterpreterInlines.h:

(JSC::DFG::isToThisAnIdentity):
(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):

• dfg/DFGClobberize.h:

(JSC::DFG::clobberize):

• dfg/DFGConstantFoldingPhase.cpp:

(JSC::DFG::ConstantFoldingPhase::foldConstants):

• dfg/DFGDoesGC.cpp:

(JSC::DFG::doesGC):

• dfg/DFGFixupPhase.cpp:

(JSC::DFG::FixupPhase::fixupNode):

• dfg/DFGNode.h:

(JSC::DFG::Node::convertToGetGlobalThis):

• dfg/DFGNodeType.h:
• dfg/DFGPredictionPropagationPhase.cpp:
• dfg/DFGSafeToExecute.h:

(JSC::DFG::safeToExecute):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compileGetGlobalThis):

• dfg/DFGSpeculativeJIT.h:
• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• ftl/FTLCapabilities.cpp:

(JSC::FTL::canCompile):

• ftl/FTLLowerDFGToB3.cpp:

(JSC::FTL::DFG::LowerDFGToB3::compileNode):
(JSC::FTL::DFG::LowerDFGToB3::compileGetGlobalThis):

• runtime/JSGlobalLexicalEnvironment.cpp:

(JSC::JSGlobalLexicalEnvironment::toThis): Deleted.

• runtime/JSGlobalLexicalEnvironment.h:
• runtime/JSGlobalObject.cpp:

(JSC::JSGlobalObject::toThis): Deleted.

• runtime/JSGlobalObject.h:

(JSC::JSGlobalObject::addressOfGlobalThis):

• runtime/JSLexicalEnvironment.cpp:

(JSC::JSLexicalEnvironment::toThis): Deleted.

• runtime/JSLexicalEnvironment.h:
• runtime/JSScope.cpp:

(JSC::JSScope::toThis):

• runtime/JSScope.h:
• runtime/StrictEvalActivation.cpp:

(JSC::StrictEvalActivation::toThis): Deleted.

• runtime/StrictEvalActivation.h:

File:

• trunk/Source/JavaScriptCore/runtime/JSGlobalObject.h (modified) (4 diffs)

trunk/Source/JavaScriptCore/runtime/JSGlobalObject.h

@@ -467 +467 @@
 public:
     typedef JSSegmentedVariableObject Base;
-    static const unsigned StructureFlags = Base::StructureFlags | HasStaticPropertyTable | OverridesGetOwnPropertySlot | OverridesGetPropertyNames | OverridesToThis | IsImmutablePrototypeExoticObject;
+    static const unsigned StructureFlags = Base::StructureFlags | HasStaticPropertyTable | OverridesGetOwnPropertySlot | OverridesGetPropertyNames | IsImmutablePrototypeExoticObject;
 
     JS_EXPORT_PRIVATE static JSGlobalObject* create(VM&, Structure*);
@@ -827 +827 @@
     VM& vm() const { return m_vm; }
     JSObject* globalThis() const;
+    WriteBarrier<JSObject>* addressOfGlobalThis() { return &m_globalThis; }
 
     static Structure* createStructure(VM& vm, JSValue prototype)
@@ -882 +883 @@
     JS_EXPORT_PRIVATE void addStaticGlobals(GlobalPropertyInfo*, int count);
 
-    JS_EXPORT_PRIVATE static JSC::JSValue toThis(JSC::JSCell*, JSC::ExecState*, ECMAMode);
-
     void setNeedsSiteSpecificQuirks(bool needQuirks) { m_needsSiteSpecificQuirks = needQuirks; }
 
@@ -889 +888 @@
     friend class LLIntOffsetsExtractor;
 
-    JS_EXPORT_PRIVATE void setGlobalThis(VM&, JSObject* globalThis);
+    void setGlobalThis(VM&, JSObject* globalThis);
 
     JS_EXPORT_PRIVATE void init(VM&);