Skip to content
Permalink
Browse files
[JSC] implement async functions proposal
https://bugs.webkit.org/show_bug.cgi?id=156147

Reviewed by Yusuke Suzuki.

Source/JavaScriptCore:

Adds support for `async` functions, proposed in https://tc39.github.io/ecmascript-asyncawait/.

On the front-end side, "await" becomes a contextual keyword when used within an async function,
which triggers parsing an AwaitExpression. "await" becomes an illegal identifier name within
these contexts. The bytecode generated from an "await" expression is identical to that generated
in a "yield" expression in a Generator, as AsyncFunction reuses generator's state machine mechanism.

There are numerous syntactic forms for language features, including a variation on ArrowFunctions,
requiring the keyword `async` to precede ArrowFormalParameters, and similarly, MethodDefinitions,
which are ordinary MethodDefinitions preceded by the keyword `async`.

An async function desugars to the following:

```
async function asyncFn() {
}

becomes:

function asyncFn() {
    let generator = {
        @GeneratorNext: function(@Generator, @generatorState, @generatorValue, @generatorResumeMode) {
          // generator state machine stuff here
        },
        @generatorState: 0,
        @generatorThis: this,
        @generatorFrame: null
    };
    return @asyncFunctionResume(generator, undefined, GeneratorResumeMode::NormalMode);
}
```

`@asyncFunctionResume()` is similar to `@generatorResume`, with the exception that it will wrap the
result of invoking `@generatorNext()` in a Promise, and will avoid allocating an iterator result
object.

If the generator has yielded (an AwaitExpression has occurred), resumption will occur automatically
once the await-expression operand is finished, via Promise chaining.

* API/JSScriptRef.cpp:
(parseScript):
* CMakeLists.txt:
* DerivedSources.make:
* JavaScriptCore.xcodeproj/project.pbxproj:
* builtins/AsyncFunctionPrototype.js: Added.
(asyncFunctionResume):
* builtins/BuiltinExecutables.cpp:
(JSC::BuiltinExecutables::createExecutable):
* bytecode/BytecodeList.json:
* bytecode/BytecodeUseDef.h:
(JSC::computeUsesForBytecodeOffset):
(JSC::computeDefsForBytecodeOffset):
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::dumpBytecode):
(JSC::CodeBlock::finishCreation):
* bytecode/UnlinkedCodeBlock.h:
(JSC::UnlinkedCodeBlock::isArrowFunction):
(JSC::UnlinkedCodeBlock::isOrdinaryArrowFunction):
(JSC::UnlinkedCodeBlock::isAsyncArrowFunction):
* bytecode/UnlinkedFunctionExecutable.cpp:
(JSC::generateUnlinkedFunctionCodeBlock):
(JSC::UnlinkedFunctionExecutable::fromGlobalCode):
(JSC::UnlinkedFunctionExecutable::unlinkedCodeBlockFor):
* bytecode/UnlinkedFunctionExecutable.h:
* bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::emitNewFunctionExpressionCommon):
(JSC::BytecodeGenerator::emitNewArrowFunctionExpression):
(JSC::BytecodeGenerator::emitNewMethodDefinition):
(JSC::BytecodeGenerator::emitNewFunction):
(JSC::BytecodeGenerator::emitLoadArrowFunctionLexicalEnvironment):
* bytecompiler/BytecodeGenerator.h:
(JSC::BytecodeGenerator::makeFunction):
* bytecompiler/NodesCodegen.cpp:
(JSC::FunctionNode::emitBytecode):
* inspector/agents/InspectorRuntimeAgent.cpp:
(Inspector::InspectorRuntimeAgent::parse):
* jit/JIT.cpp:
(JSC::JIT::privateCompileMainPass):
* jit/JIT.h:
* jit/JITOpcodes.cpp:
(JSC::JIT::emitNewFuncCommon):
(JSC::JIT::emit_op_new_async_func):
(JSC::JIT::emitNewFuncExprCommon):
(JSC::JIT::emit_op_new_async_func_exp):
* jit/JITOperations.cpp:
* jit/JITOperations.h:
* jsc.cpp:
(runInteractive):
(printUsageStatement):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* llint/LLIntSlowPaths.h:
* llint/LowLevelInterpreter.asm:
* parser/ASTBuilder.h:
(JSC::ASTBuilder::createAsyncFunctionBody):
* parser/Keywords.table:
* parser/Parser.cpp:
(JSC::Parser<LexerType>::Parser):
(JSC::Parser<LexerType>::parseInner):
(JSC::Parser<LexerType>::isArrowFunctionParameters):
(JSC::Parser<LexerType>::parseAsyncFunctionSourceElements):
(JSC::Parser<LexerType>::parseStatementListItem):
(JSC::Parser<LexerType>::parseVariableDeclarationList):
(JSC::Parser<LexerType>::parseDestructuringPattern):
(JSC::Parser<LexerType>::parseStatement):
(JSC::Parser<LexerType>::parseFunctionDeclarationStatement):
(JSC::Parser<LexerType>::parseFormalParameters):
(JSC::stringForFunctionMode):
(JSC::Parser<LexerType>::parseFunctionParameters):
(JSC::Parser<LexerType>::parseFunctionInfo):
(JSC::Parser<LexerType>::parseAsyncFunctionDeclaration):
(JSC::Parser<LexerType>::parseClass):
(JSC::Parser<LexerType>::parseExpressionOrLabelStatement):
(JSC::Parser<LexerType>::parseImportClauseItem):
(JSC::Parser<LexerType>::parseImportDeclaration):
(JSC::Parser<LexerType>::parseExportDeclaration):
(JSC::Parser<LexerType>::parseAssignmentExpression):
(JSC::Parser<LexerType>::parseAwaitExpression):
(JSC::Parser<LexerType>::parseProperty):
(JSC::Parser<LexerType>::parsePropertyMethod):
(JSC::Parser<LexerType>::parseAsyncFunctionExpression):
(JSC::Parser<LexerType>::parsePrimaryExpression):
(JSC::Parser<LexerType>::parseMemberExpression):
(JSC::Parser<LexerType>::parseArrowFunctionExpression):
(JSC::Parser<LexerType>::parseUnaryExpression):
(JSC::Parser<LexerType>::printUnexpectedTokenText):
* parser/Parser.h:
(JSC::isIdentifierOrKeyword):
(JSC::Scope::Scope):
(JSC::Scope::setSourceParseMode):
(JSC::Scope::isAsyncFunction):
(JSC::Scope::isAsyncFunctionBoundary):
(JSC::Scope::isModule):
(JSC::Scope::setIsFunction):
(JSC::Scope::setIsAsyncArrowFunction):
(JSC::Scope::setIsAsyncFunction):
(JSC::Scope::setIsAsyncFunctionBody):
(JSC::Scope::setIsAsyncArrowFunctionBody):
(JSC::Parser::ExpressionErrorClassifier::forceClassifyExpressionError):
(JSC::Parser::ExpressionErrorClassifier::propagateExpressionErrorClass):
(JSC::Parser::ExpressionErrorClassifier::indicatesPossibleAsyncArrowFunction):
(JSC::Parser::forceClassifyExpressionError):
(JSC::Parser::declarationTypeToVariableKind):
(JSC::Parser::closestParentOrdinaryFunctionNonLexicalScope):
(JSC::Parser::pushScope):
(JSC::Parser::popScopeInternal):
(JSC::Parser::matchSpecIdentifier):
(JSC::Parser::isDisallowedIdentifierAwait):
(JSC::Parser::disallowedIdentifierAwaitReason):
(JSC::parse):
* parser/ParserModes.h:
(JSC::isFunctionParseMode):
(JSC::isAsyncFunctionParseMode):
(JSC::isAsyncArrowFunctionParseMode):
(JSC::isAsyncFunctionWrapperParseMode):
(JSC::isAsyncFunctionBodyParseMode):
(JSC::isModuleParseMode):
(JSC::isProgramParseMode):
(JSC::constructAbilityForParseMode):
* parser/ParserTokens.h:
* parser/SourceCodeKey.h:
(JSC::SourceCodeKey::SourceCodeKey):
(JSC::SourceCodeKey::runtimeFlags):
(JSC::SourceCodeKey::operator==):
* parser/SyntaxChecker.h:
(JSC::SyntaxChecker::createAsyncFunctionBody):
* runtime/AsyncFunctionConstructor.cpp: Added.
(JSC::AsyncFunctionConstructor::AsyncFunctionConstructor):
(JSC::AsyncFunctionConstructor::finishCreation):
(JSC::callAsyncFunctionConstructor):
(JSC::constructAsyncFunctionConstructor):
(JSC::AsyncFunctionConstructor::getCallData):
(JSC::AsyncFunctionConstructor::getConstructData):
* runtime/AsyncFunctionConstructor.h: Added.
(JSC::AsyncFunctionConstructor::create):
(JSC::AsyncFunctionConstructor::createStructure):
* runtime/AsyncFunctionPrototype.cpp: Added.
(JSC::AsyncFunctionPrototype::AsyncFunctionPrototype):
(JSC::AsyncFunctionPrototype::finishCreation):
* runtime/AsyncFunctionPrototype.h: Added.
(JSC::AsyncFunctionPrototype::create):
(JSC::AsyncFunctionPrototype::createStructure):
* runtime/CodeCache.cpp:
(JSC::CodeCache::getGlobalCodeBlock):
(JSC::CodeCache::getProgramCodeBlock):
(JSC::CodeCache::getEvalCodeBlock):
(JSC::CodeCache::getModuleProgramCodeBlock):
(JSC::CodeCache::getFunctionExecutableFromGlobalCode):
* runtime/CodeCache.h:
* runtime/CommonIdentifiers.h:
* runtime/Completion.cpp:
(JSC::checkSyntax):
(JSC::checkModuleSyntax):
* runtime/Completion.h:
* runtime/Executable.cpp:
(JSC::ScriptExecutable::newCodeBlockFor):
(JSC::ProgramExecutable::checkSyntax):
* runtime/Executable.h:
* runtime/FunctionConstructor.cpp:
(JSC::constructFunctionSkippingEvalEnabledCheck):
* runtime/FunctionConstructor.h:
* runtime/JSAsyncFunction.cpp: Added.
(JSC::JSAsyncFunction::JSAsyncFunction):
(JSC::JSAsyncFunction::createImpl):
(JSC::JSAsyncFunction::create):
(JSC::JSAsyncFunction::createWithInvalidatedReallocationWatchpoint):
* runtime/JSAsyncFunction.h: Added.
(JSC::JSAsyncFunction::allocationSize):
(JSC::JSAsyncFunction::createStructure):
* runtime/JSFunction.cpp:
(JSC::JSFunction::getOwnPropertySlot):
* runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::init):
(JSC::JSGlobalObject::createProgramCodeBlock):
(JSC::JSGlobalObject::createEvalCodeBlock):
(JSC::JSGlobalObject::createModuleProgramCodeBlock):
* runtime/JSGlobalObject.h:
(JSC::JSGlobalObject::asyncFunctionPrototype):
(JSC::JSGlobalObject::asyncFunctionStructure):
* runtime/ModuleLoaderObject.cpp:
(JSC::moduleLoaderObjectParseModule):
* runtime/RuntimeFlags.h:
(JSC::RuntimeFlags::operator==):
(JSC::RuntimeFlags::operator!=):
* tests/stress/async-await-basic.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrow):
(shouldThrowAsync):
(let.AsyncFunction.async):
(async.asyncFunctionForProto):
(Object.getPrototypeOf.async):
(Object.getPrototypeOf.async.method):
(async):
(async.method):
(async.asyncNonConstructorDecl):
(shouldThrow.new.async):
(shouldThrow.new.async.nonConstructor):
(async.asyncDecl):
(async.f):
(MyError):
(async.asyncDeclThrower):
(shouldThrowAsync.async):
(resolveLater):
(rejectLater):
(async.resumeAfterNormal):
(O.async.resumeAfterNormal):
(resumeAfterNormalArrow.async):
(async.resumeAfterThrow):
(O.async.resumeAfterThrow):
(resumeAfterThrowArrow.async):
(catch):
* tests/stress/async-await-module-reserved-word.js: Added.
(shouldThrow):
(SyntaxError.Canstring_appeared_hereawait.checkModuleSyntaxError.String.raw.await):
(checkModuleSyntaxError.String.raw.await):
(checkModuleSyntaxError.String.raw.async.await):
(SyntaxError.Cannot.declare.named):
* tests/stress/async-await-mozilla.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrow):
(shouldThrowAsync):
(assert):
(shouldThrowSyntaxError):
(mozSemantics.async.empty):
(mozSemantics.async.simpleReturn):
(mozSemantics.async.simpleAwait):
(mozSemantics.async.simpleAwaitAsync):
(mozSemantics.async.returnOtherAsync):
(mozSemantics.async.simpleThrower):
(mozSemantics.async.delegatedThrower):
(mozSemantics.async.tryCatch):
(mozSemantics.async.tryCatchThrow):
(mozSemantics.async.wellFinally):
(mozSemantics.async.finallyMayFail):
(mozSemantics.async.embedded.async.inner):
(mozSemantics.async.embedded):
(mozSemantics.async.fib):
(mozSemantics.async.isOdd.async.isEven):
(mozSemantics.async.isOdd):
(mozSemantics.hardcoreFib.async.fib2):
(mozSemantics.namedAsyncExpr.async.simple):
(mozSemantics.async.executionOrder.async.first):
(mozSemantics.async.executionOrder.async.second):
(mozSemantics.async.executionOrder.async.third):
(mozSemantics.async.executionOrder):
(mozSemantics.async.miscellaneous):
(mozSemantics.thrower):
(mozSemantics.async.defaultArgs):
(mozSemantics.shouldThrow):
(mozSemantics):
(mozMethods.X):
(mozMethods.X.prototype.async.getValue):
(mozMethods.X.prototype.setValue):
(mozMethods.X.prototype.async.increment):
(mozMethods.X.prototype.async.getBaseClassName):
(mozMethods.X.async.getStaticValue):
(mozMethods.Y.prototype.async.getBaseClassName):
(mozMethods.Y):
(mozFunctionNameInferrence.async.test):
(mozSyntaxErrors):
* tests/stress/async-await-reserved-word.js: Added.
(assert):
(shouldThrowSyntaxError):
(AsyncFunction.async):
* tests/stress/async_arrow_functions_lexical_arguments_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrowAsync):
(noArgumentsArrow2.async):
* tests/stress/async_arrow_functions_lexical_new.target_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrowAsync):
(C1):
(C2):
(shouldThrowAsync.async):
* tests/stress/async_arrow_functions_lexical_super_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(BaseClass.prototype.baseClassValue):
(BaseClass):
(ChildClass.prototype.asyncSuperProp):
(ChildClass.prototype.asyncSuperProp2):
(ChildClass):
* tests/stress/async_arrow_functions_lexical_this_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(d.y):

Source/WebKit/mac:

* WebView/WebPreferencesPrivate.h:

Source/WebKit/win:

* Interfaces/IWebPreferencesPrivate.idl:

Source/WebKit2:

* UIProcess/API/C/WKPreferencesRefPrivate.h:
* UIProcess/API/Cocoa/WKPreferencesPrivate.h:


Canonical link: https://commits.webkit.org/176281@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@201481 268f45cc-cd09-0410-ab3c-d52691b4dbfc
  • Loading branch information
caitp committed May 28, 2016
1 parent 0068757 commit a98f79432a1a420d6536fe03c59f0650fbebbdd4
Showing with 2,853 additions and 172 deletions.
  1. +1 −1 Source/JavaScriptCore/API/JSScriptRef.cpp
  2. +4 −0 Source/JavaScriptCore/CMakeLists.txt
  3. +339 −0 Source/JavaScriptCore/ChangeLog
  4. +1 −0 Source/JavaScriptCore/DerivedSources.make
  5. +26 −0 Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
  6. +50 −0 Source/JavaScriptCore/builtins/AsyncFunctionPrototype.js
  7. +1 −1 Source/JavaScriptCore/builtins/BuiltinExecutables.cpp
  8. +2 −0 Source/JavaScriptCore/bytecode/BytecodeList.json
  9. +4 −0 Source/JavaScriptCore/bytecode/BytecodeUseDef.h
  10. +17 −1 Source/JavaScriptCore/bytecode/CodeBlock.cpp
  11. +3 −1 Source/JavaScriptCore/bytecode/UnlinkedCodeBlock.h
  12. +5 −5 Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.cpp
  13. +2 −1 Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.h
  14. +86 −10 Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp
  15. +2 −2 Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h
  16. +61 −0 Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
  17. +2 −1 Source/JavaScriptCore/inspector/agents/InspectorRuntimeAgent.cpp
  18. +2 −0 Source/JavaScriptCore/jit/JIT.cpp
  19. +2 −0 Source/JavaScriptCore/jit/JIT.h
  20. +15 −0 Source/JavaScriptCore/jit/JITOpcodes.cpp
  21. +11 −0 Source/JavaScriptCore/jit/JITOperations.cpp
  22. +2 −0 Source/JavaScriptCore/jit/JITOperations.h
  23. +2 −1 Source/JavaScriptCore/jsc.cpp
  24. +23 −0 Source/JavaScriptCore/llint/LLIntSlowPaths.cpp
  25. +2 −0 Source/JavaScriptCore/llint/LLIntSlowPaths.h
  26. +11 −1 Source/JavaScriptCore/llint/LowLevelInterpreter.asm
  27. +11 −0 Source/JavaScriptCore/parser/ASTBuilder.h
  28. +1 −0 Source/JavaScriptCore/parser/Keywords.table
  29. +354 −93 Source/JavaScriptCore/parser/Parser.cpp
  30. +124 −16 Source/JavaScriptCore/parser/Parser.h
  31. +154 −0 Source/JavaScriptCore/parser/ParserModes.h
  32. +2 −0 Source/JavaScriptCore/parser/ParserTokens.h
  33. +8 −2 Source/JavaScriptCore/parser/SourceCodeKey.h
  34. +1 −0 Source/JavaScriptCore/parser/SyntaxChecker.h
  35. +77 −0 Source/JavaScriptCore/runtime/AsyncFunctionConstructor.cpp
  36. +66 −0 Source/JavaScriptCore/runtime/AsyncFunctionConstructor.h
  37. +59 −0 Source/JavaScriptCore/runtime/AsyncFunctionPrototype.cpp
  38. +60 −0 Source/JavaScriptCore/runtime/AsyncFunctionPrototype.h
  39. +15 −13 Source/JavaScriptCore/runtime/CodeCache.cpp
  40. +6 −5 Source/JavaScriptCore/runtime/CodeCache.h
  41. +2 −0 Source/JavaScriptCore/runtime/CommonIdentifiers.h
  42. +4 −3 Source/JavaScriptCore/runtime/Completion.cpp
  43. +2 −1 Source/JavaScriptCore/runtime/Completion.h
  44. +2 −2 Source/JavaScriptCore/runtime/Executable.cpp
  45. +1 −0 Source/JavaScriptCore/runtime/Executable.h
  46. +9 −5 Source/JavaScriptCore/runtime/FunctionConstructor.cpp
  47. +1 −0 Source/JavaScriptCore/runtime/FunctionConstructor.h
  48. +69 −0 Source/JavaScriptCore/runtime/JSAsyncFunction.cpp
  49. +76 −0 Source/JavaScriptCore/runtime/JSAsyncFunction.h
  50. +1 −1 Source/JavaScriptCore/runtime/JSFunction.cpp
  51. +13 −3 Source/JavaScriptCore/runtime/JSGlobalObject.cpp
  52. +5 −0 Source/JavaScriptCore/runtime/JSGlobalObject.h
  53. +1 −1 Source/JavaScriptCore/runtime/ModuleLoaderObject.cpp
  54. +13 −2 Source/JavaScriptCore/runtime/RuntimeFlags.h
  55. +299 −0 Source/JavaScriptCore/tests/stress/async-await-basic.js
  56. +69 −0 Source/JavaScriptCore/tests/stress/async-await-module-reserved-word.js
  57. +304 −0 Source/JavaScriptCore/tests/stress/async-await-mozilla.js
  58. +163 −0 Source/JavaScriptCore/tests/stress/async-await-reserved-word.js
  59. +44 −0 Source/JavaScriptCore/tests/stress/async_arrow_functions_lexical_arguments_binding.js
  60. +52 −0 Source/JavaScriptCore/tests/stress/async_arrow_functions_lexical_new.target_binding.js
  61. +50 −0 Source/JavaScriptCore/tests/stress/async_arrow_functions_lexical_super_binding.js
  62. +27 −0 Source/JavaScriptCore/tests/stress/async_arrow_functions_lexical_this_binding.js
  63. +9 −0 Source/WebKit/mac/ChangeLog
  64. +1 −0 Source/WebKit/mac/WebView/WebPreferencesPrivate.h
  65. +9 −0 Source/WebKit/win/ChangeLog
  66. +1 −0 Source/WebKit/win/Interfaces/IWebPreferencesPrivate.idl
  67. +10 −0 Source/WebKit2/ChangeLog
  68. +1 −0 Source/WebKit2/UIProcess/API/C/WKPreferencesRefPrivate.h
  69. +1 −0 Source/WebKit2/UIProcess/API/Cocoa/WKPreferencesPrivate.h
@@ -75,7 +75,7 @@ struct OpaqueJSScript : public SourceProvider {
static bool parseScript(VM* vm, const SourceCode& source, ParserError& error)
{
return !!JSC::parse<JSC::ProgramNode>(
vm, source, Identifier(), JSParserBuiltinMode::NotBuiltin,
vm, RuntimeFlags(), source, Identifier(), JSParserBuiltinMode::NotBuiltin,
JSParserStrictMode::NotStrict, SourceParseMode::ProgramMode, SuperBinding::NotNeeded,
error);
}
@@ -609,6 +609,8 @@ set(JavaScriptCore_SOURCES
runtime/ArrayConstructor.cpp
runtime/ArrayIteratorPrototype.cpp
runtime/ArrayPrototype.cpp
runtime/AsyncFunctionConstructor.cpp
runtime/AsyncFunctionPrototype.cpp
runtime/BasicBlockLocation.cpp
runtime/BooleanConstructor.cpp
runtime/BooleanObject.cpp
@@ -683,6 +685,7 @@ set(JavaScriptCore_SOURCES
runtime/JSArrayBufferPrototype.cpp
runtime/JSArrayBufferView.cpp
runtime/JSArrayIterator.cpp
runtime/JSAsyncFunction.cpp
runtime/JSBoundFunction.cpp
runtime/JSBoundSlotBaseFunction.cpp
runtime/JSCJSValue.cpp
@@ -1208,6 +1211,7 @@ set(JavaScriptCore_BUILTINS_SOURCES
${JAVASCRIPTCORE_DIR}/builtins/ArrayConstructor.js
${JAVASCRIPTCORE_DIR}/builtins/ArrayIteratorPrototype.js
${JAVASCRIPTCORE_DIR}/builtins/ArrayPrototype.js
${JAVASCRIPTCORE_DIR}/builtins/AsyncFunctionPrototype.js
${JAVASCRIPTCORE_DIR}/builtins/DatePrototype.js
${JAVASCRIPTCORE_DIR}/builtins/FunctionPrototype.js
${JAVASCRIPTCORE_DIR}/builtins/GeneratorPrototype.js
@@ -1,3 +1,342 @@
2016-05-27 Caitlin Potter <caitp@igalia.com>

[JSC] implement async functions proposal
https://bugs.webkit.org/show_bug.cgi?id=156147

Reviewed by Yusuke Suzuki.

Adds support for `async` functions, proposed in https://tc39.github.io/ecmascript-asyncawait/.

On the front-end side, "await" becomes a contextual keyword when used within an async function,
which triggers parsing an AwaitExpression. "await" becomes an illegal identifier name within
these contexts. The bytecode generated from an "await" expression is identical to that generated
in a "yield" expression in a Generator, as AsyncFunction reuses generator's state machine mechanism.

There are numerous syntactic forms for language features, including a variation on ArrowFunctions,
requiring the keyword `async` to precede ArrowFormalParameters, and similarly, MethodDefinitions,
which are ordinary MethodDefinitions preceded by the keyword `async`.

An async function desugars to the following:

```
async function asyncFn() {
}

becomes:

function asyncFn() {
let generator = {
@generatorNext: function(@generator, @generatorState, @generatorValue, @generatorResumeMode) {
// generator state machine stuff here
},
@generatorState: 0,
@generatorThis: this,
@generatorFrame: null
};
return @asyncFunctionResume(generator, undefined, GeneratorResumeMode::NormalMode);
}
```

`@asyncFunctionResume()` is similar to `@generatorResume`, with the exception that it will wrap the
result of invoking `@generatorNext()` in a Promise, and will avoid allocating an iterator result
object.

If the generator has yielded (an AwaitExpression has occurred), resumption will occur automatically
once the await-expression operand is finished, via Promise chaining.

* API/JSScriptRef.cpp:
(parseScript):
* CMakeLists.txt:
* DerivedSources.make:
* JavaScriptCore.xcodeproj/project.pbxproj:
* builtins/AsyncFunctionPrototype.js: Added.
(asyncFunctionResume):
* builtins/BuiltinExecutables.cpp:
(JSC::BuiltinExecutables::createExecutable):
* bytecode/BytecodeList.json:
* bytecode/BytecodeUseDef.h:
(JSC::computeUsesForBytecodeOffset):
(JSC::computeDefsForBytecodeOffset):
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::dumpBytecode):
(JSC::CodeBlock::finishCreation):
* bytecode/UnlinkedCodeBlock.h:
(JSC::UnlinkedCodeBlock::isArrowFunction):
(JSC::UnlinkedCodeBlock::isOrdinaryArrowFunction):
(JSC::UnlinkedCodeBlock::isAsyncArrowFunction):
* bytecode/UnlinkedFunctionExecutable.cpp:
(JSC::generateUnlinkedFunctionCodeBlock):
(JSC::UnlinkedFunctionExecutable::fromGlobalCode):
(JSC::UnlinkedFunctionExecutable::unlinkedCodeBlockFor):
* bytecode/UnlinkedFunctionExecutable.h:
* bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::emitNewFunctionExpressionCommon):
(JSC::BytecodeGenerator::emitNewArrowFunctionExpression):
(JSC::BytecodeGenerator::emitNewMethodDefinition):
(JSC::BytecodeGenerator::emitNewFunction):
(JSC::BytecodeGenerator::emitLoadArrowFunctionLexicalEnvironment):
* bytecompiler/BytecodeGenerator.h:
(JSC::BytecodeGenerator::makeFunction):
* bytecompiler/NodesCodegen.cpp:
(JSC::FunctionNode::emitBytecode):
* inspector/agents/InspectorRuntimeAgent.cpp:
(Inspector::InspectorRuntimeAgent::parse):
* jit/JIT.cpp:
(JSC::JIT::privateCompileMainPass):
* jit/JIT.h:
* jit/JITOpcodes.cpp:
(JSC::JIT::emitNewFuncCommon):
(JSC::JIT::emit_op_new_async_func):
(JSC::JIT::emitNewFuncExprCommon):
(JSC::JIT::emit_op_new_async_func_exp):
* jit/JITOperations.cpp:
* jit/JITOperations.h:
* jsc.cpp:
(runInteractive):
(printUsageStatement):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* llint/LLIntSlowPaths.h:
* llint/LowLevelInterpreter.asm:
* parser/ASTBuilder.h:
(JSC::ASTBuilder::createAsyncFunctionBody):
* parser/Keywords.table:
* parser/Parser.cpp:
(JSC::Parser<LexerType>::Parser):
(JSC::Parser<LexerType>::parseInner):
(JSC::Parser<LexerType>::isArrowFunctionParameters):
(JSC::Parser<LexerType>::parseAsyncFunctionSourceElements):
(JSC::Parser<LexerType>::parseStatementListItem):
(JSC::Parser<LexerType>::parseVariableDeclarationList):
(JSC::Parser<LexerType>::parseDestructuringPattern):
(JSC::Parser<LexerType>::parseStatement):
(JSC::Parser<LexerType>::parseFunctionDeclarationStatement):
(JSC::Parser<LexerType>::parseFormalParameters):
(JSC::stringForFunctionMode):
(JSC::Parser<LexerType>::parseFunctionParameters):
(JSC::Parser<LexerType>::parseFunctionInfo):
(JSC::Parser<LexerType>::parseAsyncFunctionDeclaration):
(JSC::Parser<LexerType>::parseClass):
(JSC::Parser<LexerType>::parseExpressionOrLabelStatement):
(JSC::Parser<LexerType>::parseImportClauseItem):
(JSC::Parser<LexerType>::parseImportDeclaration):
(JSC::Parser<LexerType>::parseExportDeclaration):
(JSC::Parser<LexerType>::parseAssignmentExpression):
(JSC::Parser<LexerType>::parseAwaitExpression):
(JSC::Parser<LexerType>::parseProperty):
(JSC::Parser<LexerType>::parsePropertyMethod):
(JSC::Parser<LexerType>::parseAsyncFunctionExpression):
(JSC::Parser<LexerType>::parsePrimaryExpression):
(JSC::Parser<LexerType>::parseMemberExpression):
(JSC::Parser<LexerType>::parseArrowFunctionExpression):
(JSC::Parser<LexerType>::parseUnaryExpression):
(JSC::Parser<LexerType>::printUnexpectedTokenText):
* parser/Parser.h:
(JSC::isIdentifierOrKeyword):
(JSC::Scope::Scope):
(JSC::Scope::setSourceParseMode):
(JSC::Scope::isAsyncFunction):
(JSC::Scope::isAsyncFunctionBoundary):
(JSC::Scope::isModule):
(JSC::Scope::setIsFunction):
(JSC::Scope::setIsAsyncArrowFunction):
(JSC::Scope::setIsAsyncFunction):
(JSC::Scope::setIsAsyncFunctionBody):
(JSC::Scope::setIsAsyncArrowFunctionBody):
(JSC::Parser::ExpressionErrorClassifier::forceClassifyExpressionError):
(JSC::Parser::ExpressionErrorClassifier::propagateExpressionErrorClass):
(JSC::Parser::ExpressionErrorClassifier::indicatesPossibleAsyncArrowFunction):
(JSC::Parser::forceClassifyExpressionError):
(JSC::Parser::declarationTypeToVariableKind):
(JSC::Parser::closestParentOrdinaryFunctionNonLexicalScope):
(JSC::Parser::pushScope):
(JSC::Parser::popScopeInternal):
(JSC::Parser::matchSpecIdentifier):
(JSC::Parser::isDisallowedIdentifierAwait):
(JSC::Parser::disallowedIdentifierAwaitReason):
(JSC::parse):
* parser/ParserModes.h:
(JSC::isFunctionParseMode):
(JSC::isAsyncFunctionParseMode):
(JSC::isAsyncArrowFunctionParseMode):
(JSC::isAsyncFunctionWrapperParseMode):
(JSC::isAsyncFunctionBodyParseMode):
(JSC::isModuleParseMode):
(JSC::isProgramParseMode):
(JSC::constructAbilityForParseMode):
* parser/ParserTokens.h:
* parser/SourceCodeKey.h:
(JSC::SourceCodeKey::SourceCodeKey):
(JSC::SourceCodeKey::runtimeFlags):
(JSC::SourceCodeKey::operator==):
* parser/SyntaxChecker.h:
(JSC::SyntaxChecker::createAsyncFunctionBody):
* runtime/AsyncFunctionConstructor.cpp: Added.
(JSC::AsyncFunctionConstructor::AsyncFunctionConstructor):
(JSC::AsyncFunctionConstructor::finishCreation):
(JSC::callAsyncFunctionConstructor):
(JSC::constructAsyncFunctionConstructor):
(JSC::AsyncFunctionConstructor::getCallData):
(JSC::AsyncFunctionConstructor::getConstructData):
* runtime/AsyncFunctionConstructor.h: Added.
(JSC::AsyncFunctionConstructor::create):
(JSC::AsyncFunctionConstructor::createStructure):
* runtime/AsyncFunctionPrototype.cpp: Added.
(JSC::AsyncFunctionPrototype::AsyncFunctionPrototype):
(JSC::AsyncFunctionPrototype::finishCreation):
* runtime/AsyncFunctionPrototype.h: Added.
(JSC::AsyncFunctionPrototype::create):
(JSC::AsyncFunctionPrototype::createStructure):
* runtime/CodeCache.cpp:
(JSC::CodeCache::getGlobalCodeBlock):
(JSC::CodeCache::getProgramCodeBlock):
(JSC::CodeCache::getEvalCodeBlock):
(JSC::CodeCache::getModuleProgramCodeBlock):
(JSC::CodeCache::getFunctionExecutableFromGlobalCode):
* runtime/CodeCache.h:
* runtime/CommonIdentifiers.h:
* runtime/Completion.cpp:
(JSC::checkSyntax):
(JSC::checkModuleSyntax):
* runtime/Completion.h:
* runtime/Executable.cpp:
(JSC::ScriptExecutable::newCodeBlockFor):
(JSC::ProgramExecutable::checkSyntax):
* runtime/Executable.h:
* runtime/FunctionConstructor.cpp:
(JSC::constructFunctionSkippingEvalEnabledCheck):
* runtime/FunctionConstructor.h:
* runtime/JSAsyncFunction.cpp: Added.
(JSC::JSAsyncFunction::JSAsyncFunction):
(JSC::JSAsyncFunction::createImpl):
(JSC::JSAsyncFunction::create):
(JSC::JSAsyncFunction::createWithInvalidatedReallocationWatchpoint):
* runtime/JSAsyncFunction.h: Added.
(JSC::JSAsyncFunction::allocationSize):
(JSC::JSAsyncFunction::createStructure):
* runtime/JSFunction.cpp:
(JSC::JSFunction::getOwnPropertySlot):
* runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::init):
(JSC::JSGlobalObject::createProgramCodeBlock):
(JSC::JSGlobalObject::createEvalCodeBlock):
(JSC::JSGlobalObject::createModuleProgramCodeBlock):
* runtime/JSGlobalObject.h:
(JSC::JSGlobalObject::asyncFunctionPrototype):
(JSC::JSGlobalObject::asyncFunctionStructure):
* runtime/ModuleLoaderObject.cpp:
(JSC::moduleLoaderObjectParseModule):
* runtime/RuntimeFlags.h:
(JSC::RuntimeFlags::operator==):
(JSC::RuntimeFlags::operator!=):
* tests/stress/async-await-basic.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrow):
(shouldThrowAsync):
(let.AsyncFunction.async):
(async.asyncFunctionForProto):
(Object.getPrototypeOf.async):
(Object.getPrototypeOf.async.method):
(async):
(async.method):
(async.asyncNonConstructorDecl):
(shouldThrow.new.async):
(shouldThrow.new.async.nonConstructor):
(async.asyncDecl):
(async.f):
(MyError):
(async.asyncDeclThrower):
(shouldThrowAsync.async):
(resolveLater):
(rejectLater):
(async.resumeAfterNormal):
(O.async.resumeAfterNormal):
(resumeAfterNormalArrow.async):
(async.resumeAfterThrow):
(O.async.resumeAfterThrow):
(resumeAfterThrowArrow.async):
(catch):
* tests/stress/async-await-module-reserved-word.js: Added.
(shouldThrow):
(SyntaxError.Canstring_appeared_hereawait.checkModuleSyntaxError.String.raw.await):
(checkModuleSyntaxError.String.raw.await):
(checkModuleSyntaxError.String.raw.async.await):
(SyntaxError.Cannot.declare.named):
* tests/stress/async-await-mozilla.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrow):
(shouldThrowAsync):
(assert):
(shouldThrowSyntaxError):
(mozSemantics.async.empty):
(mozSemantics.async.simpleReturn):
(mozSemantics.async.simpleAwait):
(mozSemantics.async.simpleAwaitAsync):
(mozSemantics.async.returnOtherAsync):
(mozSemantics.async.simpleThrower):
(mozSemantics.async.delegatedThrower):
(mozSemantics.async.tryCatch):
(mozSemantics.async.tryCatchThrow):
(mozSemantics.async.wellFinally):
(mozSemantics.async.finallyMayFail):
(mozSemantics.async.embedded.async.inner):
(mozSemantics.async.embedded):
(mozSemantics.async.fib):
(mozSemantics.async.isOdd.async.isEven):
(mozSemantics.async.isOdd):
(mozSemantics.hardcoreFib.async.fib2):
(mozSemantics.namedAsyncExpr.async.simple):
(mozSemantics.async.executionOrder.async.first):
(mozSemantics.async.executionOrder.async.second):
(mozSemantics.async.executionOrder.async.third):
(mozSemantics.async.executionOrder):
(mozSemantics.async.miscellaneous):
(mozSemantics.thrower):
(mozSemantics.async.defaultArgs):
(mozSemantics.shouldThrow):
(mozSemantics):
(mozMethods.X):
(mozMethods.X.prototype.async.getValue):
(mozMethods.X.prototype.setValue):
(mozMethods.X.prototype.async.increment):
(mozMethods.X.prototype.async.getBaseClassName):
(mozMethods.X.async.getStaticValue):
(mozMethods.Y.prototype.async.getBaseClassName):
(mozMethods.Y):
(mozFunctionNameInferrence.async.test):
(mozSyntaxErrors):
* tests/stress/async-await-reserved-word.js: Added.
(assert):
(shouldThrowSyntaxError):
(AsyncFunction.async):
* tests/stress/async_arrow_functions_lexical_arguments_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrowAsync):
(noArgumentsArrow2.async):
* tests/stress/async_arrow_functions_lexical_new.target_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(shouldThrowAsync):
(C1):
(C2):
(shouldThrowAsync.async):
* tests/stress/async_arrow_functions_lexical_super_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(BaseClass.prototype.baseClassValue):
(BaseClass):
(ChildClass.prototype.asyncSuperProp):
(ChildClass.prototype.asyncSuperProp2):
(ChildClass):
* tests/stress/async_arrow_functions_lexical_this_binding.js: Added.
(shouldBe):
(shouldBeAsync):
(d.y):

2016-05-27 Saam barati <sbarati@apple.com>

DebuggerCallFrame crashes when updated with the globalExec because neither ShadowChicken's algorithm nor StackVisitor's algorithm reasons about the globalExec
@@ -84,6 +84,7 @@ JavaScriptCore_BUILTINS_SOURCES = \
$(JavaScriptCore)/builtins/ArrayConstructor.js \
$(JavaScriptCore)/builtins/ArrayIteratorPrototype.js \
$(JavaScriptCore)/builtins/ArrayPrototype.js \
$(JavaScriptCore)/builtins/AsyncFunctionPrototype.js \
$(JavaScriptCore)/builtins/DatePrototype.js \
$(JavaScriptCore)/builtins/FunctionPrototype.js \
$(JavaScriptCore)/builtins/GeneratorPrototype.js \

0 comments on commit a98f794

Please sign in to comment.