Changeset 200038 in webkit for trunk/Source/JavaScriptCore/parser/ParserFunctionInfo.h

Timestamp:

Apr 25, 2016, 12:08:53 PM (9 years ago)

Author:

[email protected]

Message:

We don't have to parse a function's parameters every time if the function is in the source provider cache
​https://bugs.webkit.org/show_bug.cgi?id=156943

Reviewed by Filip Pizlo.

This patch makes a few changes to make parsing inner functions
faster.

First, we were always parsing an inner function's parameter
list using the templatized TreeBuiler. This means if our parent scope
was building an AST, we ended up building AST nodes for the inner
function's parameter list even though these nodes would go unused.
This patch fixes that to *always* build an inner function's parameter
list using the SyntaxChecker. (Note that this is consistent now with
always building an inner function's body with a SyntaxChecker.)

Second, we were always parsing an inner function's parameter list
even if we had that function saved in the source provider cache.
I've fixed that bug and made it so that we skip over the parsing
of a function's parameter list when it's in the source provider
cache. We could probably enhance this in the future to skip
over the entirety of a function starting at the "function"
keyword or any other start of the function (depending on
the function type: arrow function, method, etc).

This patch also renames a few fields. First, I fixed a typo
from "tocken" => "token" for a few field names. Secondly,
I renamed a field that was called 'bodyStartColumn' to
'parametersStartColumn' because the field really held the
parameter list's start column.

I'm benchmarking this as a 1.5-2% octane/jquery speedup
on a 15" MBP.

• parser/ASTBuilder.h:

(JSC::ASTBuilder::createFunctionExpr):
(JSC::ASTBuilder::createMethodDefinition):
(JSC::ASTBuilder::createArrowFunctionExpr):
(JSC::ASTBuilder::createGetterOrSetterProperty):
(JSC::ASTBuilder::createFuncDeclStatement):

• parser/Lexer.cpp:

(JSC::Lexer<T>::lex):

• parser/Lexer.h:

(JSC::Lexer::currentPosition):
(JSC::Lexer::positionBeforeLastNewline):
(JSC::Lexer::lastTokenLocation):
(JSC::Lexer::setLastLineNumber):
(JSC::Lexer::lastLineNumber):
(JSC::Lexer::prevTerminator):

• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseInner):
(JSC::Parser<LexerType>::parseGeneratorFunctionSourceElements):
(JSC::Parser<LexerType>::parseFunctionBody):
(JSC::stringForFunctionMode):
(JSC::Parser<LexerType>::parseFunctionParameters):
(JSC::Parser<LexerType>::parseFunctionInfo):

• parser/Parser.h:

(JSC::Scope::usedVariablesContains):
(JSC::Scope::forEachUsedVariable):
(JSC::Scope::useVariable):
(JSC::Scope::copyCapturedVariablesToVector):
(JSC::Scope::fillParametersForSourceProviderCache):
(JSC::Scope::restoreFromSourceProviderCache):

• parser/ParserFunctionInfo.h:
• parser/SourceProviderCacheItem.h:

(JSC::SourceProviderCacheItem::endFunctionToken):
(JSC::SourceProviderCacheItem::usedVariables):
(JSC::SourceProviderCacheItem::SourceProviderCacheItem):

File:

• trunk/Source/JavaScriptCore/parser/ParserFunctionInfo.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/parser/ParserFunctionInfo.h

@@ -32 +32 @@
 struct ParserFunctionInfo {
     const Identifier* name = 0;
-    typename TreeBuilder::FormalParameterList parameters = 0;
     typename TreeBuilder::FunctionBody body = 0;
     unsigned parameterCount = 0;
@@ -39 +38 @@
     int startLine = 0;
     int endLine = 0;
-    unsigned bodyStartColumn = 0;
+    unsigned parametersStartColumn = 0;
 };