Changeset 179429 in webkit for trunk/Source/JavaScriptCore/runtime/JSCell.cpp

Timestamp:

Jan 30, 2015, 5:23:56 PM (10 years ago)

Author:

Yusuke Suzuki

Message:

Implement ES6 Symbol
​https://bugs.webkit.org/show_bug.cgi?id=140435

Reviewed by Geoffrey Garen.

Source/JavaScriptCore:

This patch implements ES6 Symbol. In this patch, we don't support
Symbol.keyFor, Symbol.for, Object.getOwnPropertySymbols. They will be
supported in the subsequent patches.

Since ES6 Symbol is introduced as new primitive value, we implement
Symbol as a derived class from JSCell. And now JSValue accepts Symbol*
as a new primitive value.

Symbol has a *unique* flagged StringImpl* as an uid. Which pointer
value represents the Symbol's identity. So don't compare Symbol's
JSCell pointer value for comparison.
This enables re-producing Symbol primitive value from StringImpl* uid
by executingSymbol::create(vm, uid). This is needed to produce
Symbol primitive values from stored StringImpl* in Object.getOwnPropertySymbols.

And Symbol.Description is folded into the string value of Symbol's uid.
By doing so, we can represent ES6 Symbol without extending current PropertyTable key; StringImpl*.

• CMakeLists.txt:
• DerivedSources.make:
• JavaScriptCore.order:
• JavaScriptCore.vcxproj/JavaScriptCore.vcxproj:
• JavaScriptCore.vcxproj/JavaScriptCore.vcxproj.filters:
• JavaScriptCore.xcodeproj/project.pbxproj:
• builtins/BuiltinExecutables.cpp:

(JSC::BuiltinExecutables::createBuiltinExecutable):

• builtins/BuiltinNames.h:
• dfg/DFGOperations.cpp:

(JSC::DFG::operationPutByValInternal):

• inspector/JSInjectedScriptHost.cpp:

(Inspector::JSInjectedScriptHost::subtype):

• interpreter/Interpreter.cpp:
• jit/JITOperations.cpp:

(JSC::getByVal):

• llint/LLIntData.cpp:

(JSC::LLInt::Data::performAssertions):

• llint/LLIntSlowPaths.cpp:

(JSC::LLInt::getByVal):
(JSC::LLInt::LLINT_SLOW_PATH_DECL):

• llint/LowLevelInterpreter.asm:
• runtime/CommonIdentifiers.h:
• runtime/CommonSlowPaths.cpp:

(JSC::SLOW_PATH_DECL):

• runtime/CommonSlowPaths.h:

(JSC::CommonSlowPaths::opIn):

• runtime/ExceptionHelpers.cpp:

(JSC::createUndefinedVariableError):

• runtime/JSCJSValue.cpp:

(JSC::JSValue::synthesizePrototype):
(JSC::JSValue::dumpInContextAssumingStructure):
(JSC::JSValue::toStringSlowCase):

• runtime/JSCJSValue.h:
• runtime/JSCJSValueInlines.h:

(JSC::JSValue::isSymbol):
(JSC::JSValue::isPrimitive):
(JSC::JSValue::toPropertyKey):

It represents ToPropertyKey abstract operation in the ES6 spec.
It cleans up the old implementation's isName checks.
And to prevent performance regressions in

js/regress/fold-get-by-id-to-multi-get-by-offset-rare-int.html
js/regress/fold-get-by-id-to-multi-get-by-offset.html

we annnotate this function as ALWAYS_INLINE.

(JSC::JSValue::getPropertySlot):
(JSC::JSValue::get):
(JSC::JSValue::equalSlowCaseInline):
(JSC::JSValue::strictEqualSlowCaseInline):

• runtime/JSCell.cpp:

(JSC::JSCell::put):
(JSC::JSCell::putByIndex):
(JSC::JSCell::toPrimitive):
(JSC::JSCell::getPrimitiveNumber):
(JSC::JSCell::toNumber):
(JSC::JSCell::toObject):

• runtime/JSCell.h:
• runtime/JSCellInlines.h:

(JSC::JSCell::isSymbol):
(JSC::JSCell::toBoolean):
(JSC::JSCell::pureToBoolean):

• runtime/JSGlobalObject.cpp:

(JSC::JSGlobalObject::init):
(JSC::JSGlobalObject::visitChildren):

• runtime/JSGlobalObject.h:

(JSC::JSGlobalObject::symbolPrototype):
(JSC::JSGlobalObject::symbolObjectStructure):

• runtime/JSONObject.cpp:

(JSC::Stringifier::Stringifier):

• runtime/JSSymbolTableObject.cpp:

(JSC::JSSymbolTableObject::getOwnNonIndexPropertyNames):

• runtime/JSType.h:
• runtime/JSTypeInfo.h:

(JSC::TypeInfo::isName): Deleted.

• runtime/MapData.cpp:

(JSC::MapData::find):
(JSC::MapData::add):
(JSC::MapData::remove):
(JSC::MapData::replaceAndPackBackingStore):

• runtime/MapData.h:

(JSC::MapData::clear):

• runtime/NameInstance.h: Removed.
• runtime/NamePrototype.cpp: Removed.
• runtime/ObjectConstructor.cpp:

(JSC::objectConstructorGetOwnPropertyDescriptor):
(JSC::objectConstructorDefineProperty):

• runtime/ObjectPrototype.cpp:

(JSC::objectProtoFuncHasOwnProperty):
(JSC::objectProtoFuncDefineGetter):
(JSC::objectProtoFuncDefineSetter):
(JSC::objectProtoFuncLookupGetter):
(JSC::objectProtoFuncLookupSetter):
(JSC::objectProtoFuncPropertyIsEnumerable):

• runtime/Operations.cpp:

(JSC::jsTypeStringForValue):
(JSC::jsIsObjectType):

• runtime/PrivateName.h:

(JSC::PrivateName::PrivateName):
(JSC::PrivateName::operator==):
(JSC::PrivateName::operator!=):

• runtime/PropertyMapHashTable.h:

(JSC::PropertyTable::find):
(JSC::PropertyTable::get):

• runtime/PropertyName.h:

(JSC::PropertyName::PropertyName):
(JSC::PropertyName::publicName):

• runtime/SmallStrings.h:
• runtime/StringConstructor.cpp:

(JSC::callStringConstructor):

In ES6, String constructor accepts Symbol to execute String(symbol).

• runtime/Structure.cpp:

(JSC::Structure::getPropertyNamesFromStructure):

• runtime/StructureInlines.h:

(JSC::Structure::prototypeForLookup):

• runtime/Symbol.cpp: Added.

(JSC::Symbol::Symbol):
(JSC::SymbolObject::create):
(JSC::Symbol::toPrimitive):
(JSC::Symbol::toBoolean):
(JSC::Symbol::getPrimitiveNumber):
(JSC::Symbol::toObject):
(JSC::Symbol::toNumber):
(JSC::Symbol::destroy):
(JSC::Symbol::descriptiveString):

• runtime/Symbol.h: Added.

(JSC::Symbol::createStructure):
(JSC::Symbol::create):
(JSC::Symbol::privateName):
(JSC::Symbol::finishCreation):
(JSC::asSymbol):

• runtime/SymbolConstructor.cpp: Renamed from Source/JavaScriptCore/runtime/NameConstructor.cpp.

(JSC::SymbolConstructor::SymbolConstructor):
(JSC::SymbolConstructor::finishCreation):
(JSC::callSymbol):
(JSC::SymbolConstructor::getConstructData):
(JSC::SymbolConstructor::getCallData):

• runtime/SymbolConstructor.h: Renamed from Source/JavaScriptCore/runtime/NameConstructor.h.

(JSC::SymbolConstructor::create):
(JSC::SymbolConstructor::createStructure):

• runtime/SymbolObject.cpp: Renamed from Source/JavaScriptCore/runtime/NameInstance.cpp.

(JSC::SymbolObject::SymbolObject):
(JSC::SymbolObject::finishCreation):
(JSC::SymbolObject::defaultValue):

Now JSC doesn't support @@toPrimitive. So instead of it, we implement
Symbol.prototype[@@toPrimitive] as ES5 Symbol.DefaultValue.

• runtime/SymbolObject.h: Added.

(JSC::SymbolObject::create):
(JSC::SymbolObject::internalValue):
(JSC::SymbolObject::createStructure):

• runtime/SymbolPrototype.cpp: Added.

(JSC::SymbolPrototype::SymbolPrototype):
(JSC::SymbolPrototype::finishCreation):
(JSC::SymbolPrototype::getOwnPropertySlot):
(JSC::symbolProtoFuncToString):
(JSC::symbolProtoFuncValueOf):

• runtime/SymbolPrototype.h: Renamed from Source/JavaScriptCore/runtime/NamePrototype.h.

(JSC::SymbolPrototype::create):
(JSC::SymbolPrototype::createStructure):

SymbolPrototype object is ordinary JS object. Not wrapper object of Symbol.
It is tested in js/symbol-prototype-is-ordinary-object.html.

• runtime/VM.cpp:

(JSC::VM::VM):

• runtime/VM.h:

Source/WTF:

Introduce new unique string mechanizm into StringImpl.
It is used for implementing Symbol which holds a Description value.

• wtf/text/AtomicString.h:

(WTF::AtomicString::add):
(WTF::AtomicString::addWithStringTableProvider):

Previously, we checked isAtomic() or !length(). This guard can filter out EmptyUnique.
But now, we introduced new unique StringImpl. Since it has an actual string value, we need to check isUnique().

• wtf/text/StringImpl.cpp:

(WTF::StringImpl::~StringImpl):
(WTF::StringImpl::createUnique):

In createUnique, we leverage Substring mechanizm to produce a new unique
string from an existing string.

• wtf/text/StringImpl.h:

(WTF::StringImpl::StringImpl):
(WTF::StringImpl::createUniqueEmpty):
(WTF::StringImpl::flagIsUnique):
(WTF::StringImpl::isUnique):
(WTF::StringImpl::setIsAtomic):
(WTF::StringImpl::createEmptyUnique): Deleted.
(WTF::StringImpl::isEmptyUnique): Deleted.

Instead of EmptyUnique, we introduced new flag to StringImpl, isUnique.
While EmptyUnique cannot hold any string values except for empty string,
the unique StringImpl can hold any String values.
We fold the Symbol's descriptiveString value here.

• wtf/text/StringStatics.cpp:

(WTF::StringImpl::hashAndFlagsForUnique):
(WTF::StringImpl::hashAndFlagsForEmptyUnique): Deleted.

LayoutTests:

• js/script-tests/symbol-abstract-equality-comparison.js: Added.

(Pair):
(relationalOperators.forEach):

• js/script-tests/symbol-abstract-relational-comparison.js: Added.

(relationalOperators.forEach):

• js/script-tests/symbol-in-map.js: Added.

(set shouldBe):

• js/script-tests/symbol-object.js: Added.
• js/script-tests/symbol-prototype-is-ordinary-object.js: Added.
• js/script-tests/symbol-strict-equality-comparison.js: Added.

(Pair):
(relationalOperators.forEach):

• js/script-tests/symbol-tostring.js: Added.
• js/script-tests/symbols.js: Renamed from LayoutTests/js/script-tests/names.js.

(forIn):

• js/symbol-abstract-equality-comparison-expected.txt: Added.
• js/symbol-abstract-equality-comparison.html: Copied from LayoutTests/js/names.html.
• js/symbol-abstract-relational-comparison-expected.txt: Added.
• js/symbol-abstract-relational-comparison.html: Copied from LayoutTests/js/names.html.
• js/symbol-in-map-expected.txt: Added.
• js/symbol-in-map.html: Copied from LayoutTests/js/names.html.
• js/symbol-object-expected.txt: Added.
• js/symbol-object.html: Copied from LayoutTests/js/names.html.
• js/symbol-prototype-is-ordinary-object-expected.txt: Added.
• js/symbol-prototype-is-ordinary-object.html: Copied from LayoutTests/js/names.html.
• js/symbol-strict-equality-comparison-expected.txt: Added.
• js/symbol-strict-equality-comparison.html: Copied from LayoutTests/js/names.html.
• js/symbol-tostring-expected.txt: Added.
• js/symbol-tostring.html: Copied from LayoutTests/js/names.html.
• js/symbols-expected.txt: Renamed from LayoutTests/js/names-expected.txt.
• js/symbols.html: Renamed from LayoutTests/js/names.html.

File:

• trunk/Source/JavaScriptCore/runtime/JSCell.cpp (modified) (6 diffs)

trunk/Source/JavaScriptCore/runtime/JSCell.cpp

@@ -97 +97 @@
 void JSCell::put(JSCell* cell, ExecState* exec, PropertyName identifier, JSValue value, PutPropertySlot& slot)
 {
-    if (cell->isString()) {
+    if (cell->isString() || cell->isSymbol()) {
         JSValue(cell).putToPrimitive(exec, identifier, value, slot);
         return;
@@ -107 +107 @@
 void JSCell::putByIndex(JSCell* cell, ExecState* exec, unsigned identifier, JSValue value, bool shouldThrow)
 {
-    if (cell->isString()) {
+    if (cell->isString() || cell->isSymbol()) {
         PutPropertySlot slot(cell, shouldThrow);
         JSValue(cell).putToPrimitive(exec, Identifier::from(exec, identifier), value, slot);
@@ -139 +139 @@
     if (isString())
         return static_cast<const JSString*>(this)->toPrimitive(exec, preferredType);
+    if (isSymbol())
+        return static_cast<const Symbol*>(this)->toPrimitive(exec, preferredType);
     return static_cast<const JSObject*>(this)->toPrimitive(exec, preferredType);
 }
@@ -146 +148 @@
     if (isString())
         return static_cast<const JSString*>(this)->getPrimitiveNumber(exec, number, value);
+    if (isSymbol())
+        return static_cast<const Symbol*>(this)->getPrimitiveNumber(exec, number, value);
     return static_cast<const JSObject*>(this)->getPrimitiveNumber(exec, number, value);
 }
@@ -153 +157 @@
     if (isString())
         return static_cast<const JSString*>(this)->toNumber(exec);
+    if (isSymbol())
+        return static_cast<const Symbol*>(this)->toNumber(exec);
     return static_cast<const JSObject*>(this)->toNumber(exec);
 }
@@ -160 +166 @@
     if (isString())
         return static_cast<const JSString*>(this)->toObject(exec, globalObject);
+    if (isSymbol())
+        return static_cast<const Symbol*>(this)->toObject(exec, globalObject);
     ASSERT(isObject());
     return jsCast<JSObject*>(const_cast<JSCell*>(this));