commit ea92da194ad2b2ff04d727272127c6222f1d8a87
author yusukesuzuki@slowstart.org <yusukesuzuki@slowstart.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Thu Oct 18 13:04:22 2018 +0000
committer yusukesuzuki@slowstart.org <yusukesuzuki@slowstart.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Thu Oct 18 13:04:22 2018 +0000
tree 64f13d4ff73062d4da5b0cc8cd16f3005e0ddca3
parent b858a8e7b74fb5e7a4a92fe69600baf957764d33

[JSC] JSC should have "parseFunction" to optimize Function constructor
https://bugs.webkit.org/show_bug.cgi?id=190340

Reviewed by Mark Lam.

JSTests:

This patch fixes the line number of syntax errors raised by the Function constructor,
since we now parse the final code only once. And we no longer use block statement
for Function constructor's parsing.

* ChakraCore/test/Function/FuncBodyES5.baseline-jsc:
* stress/function-cache-with-parameters-end-position.js: Added.
(shouldBe):
(shouldThrow):
(i.anonymous):
* stress/function-constructor-name.js: Added.
(shouldBe):
(GeneratorFunction):
(AsyncFunction.async):
(AsyncGeneratorFunction.async):
(anonymous):
(async.anonymous):
* test262/expectations.yaml:

LayoutTests/imported/w3c:

* web-platform-tests/html/webappapis/scripting/events/inline-event-handler-ordering-expected.txt:
* web-platform-tests/html/webappapis/scripting/events/invalid-uncompiled-raw-handler-compiled-late-expected.txt:
* web-platform-tests/html/webappapis/scripting/processing-model-2/compile-error-in-attribute-expected.txt:
* web-platform-tests/html/webappapis/scripting/processing-model-2/compile-error-in-body-onerror-expected.txt:

Source/JavaScriptCore:

The current Function constructor is suboptimal. We parse the piece of the same code three times to meet
the spec requirement. (1) check parameters syntax, (2) check body syntax, and (3) parse the entire function.
And to parse 1-3 correctly, we create two strings, the parameters and the entire function. This operation
is really costly and ideally we should meet the above requirement by the one time parsing.

To meet the above requirement, we add a special function for Parser, parseSingleFunction. This function
takes `std::optional<int> functionConstructorParametersEndPosition` and check this end position is correct in the parser.
For example, if we run the code,

    Function('/*', '*/){')

According to the spec, this should produce '/*' parameter string and '*/){' body string. And parameter
string should be syntax-checked by the parser, and raise the error since it is incorrect. Instead of doing
that, in our implementation, we first create the entire string.

    function anonymous(/*) {
        */){
    }

And we parse it. At that time, we also pass the end position of the parameters to the parser. In the above case,
the position of the `function anonymous(/*)' <> is passed. And in the parser, we check that the last token
offset of the parameters is the given end position. This check allows us to raise the error correctly to the
above example while we parse the entire function only once. And we do not need to create two strings too.

This improves the performance of the Function constructor significantly. And web-tooling-benchmark/uglify-js is
significantly sped up (28.2%).

Before:
    uglify-js:  2.94 runs/s
After:
    uglify-js:  3.77 runs/s

* bytecode/UnlinkedFunctionExecutable.cpp:
(JSC::UnlinkedFunctionExecutable::fromGlobalCode):
* bytecode/UnlinkedFunctionExecutable.h:
* parser/Parser.cpp:
(JSC::Parser<LexerType>::parseInner):
(JSC::Parser<LexerType>::parseSingleFunction):
(JSC::Parser<LexerType>::parseFunctionInfo):
(JSC::Parser<LexerType>::parseFunctionDeclaration):
(JSC::Parser<LexerType>::parseAsyncFunctionDeclaration):
* parser/Parser.h:
(JSC::Parser<LexerType>::parse):
(JSC::parse):
(JSC::parseFunctionForFunctionConstructor):
* parser/ParserModes.h:
* parser/ParserTokens.h:
(JSC::JSTextPosition::JSTextPosition):
(JSC::JSTokenLocation::JSTokenLocation): Deleted.
* parser/SourceCodeKey.h:
(JSC::SourceCodeKey::SourceCodeKey):
(JSC::SourceCodeKey::operator== const):
* runtime/CodeCache.cpp:
(JSC::CodeCache::getUnlinkedGlobalCodeBlock):
(JSC::CodeCache::getUnlinkedGlobalFunctionExecutable):
* runtime/CodeCache.h:
* runtime/FunctionConstructor.cpp:
(JSC::constructFunctionSkippingEvalEnabledCheck):
* runtime/FunctionExecutable.cpp:
(JSC::FunctionExecutable::fromGlobalCode):
* runtime/FunctionExecutable.h:

LayoutTests:

* fast/dom/attribute-event-listener-errors-expected.txt:
* fast/events/attribute-listener-deletion-crash-expected.txt:
* fast/events/window-onerror-syntax-error-in-attr-expected.txt:
* js/dom/invalid-syntax-for-function-expected.txt:
* js/dom/script-start-end-locations-expected.txt:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@237254 268f45cc-cd09-0410-ab3c-d52691b4dbfc