https://bugs.webkit.org/show_bug.cgi?id=103764

Reviewed by Michael Saboff.

A fairly logically simple patch.  We now track the start of the
unique portion of a functions body, and use that as our key for
unlinked function code.  This allows us to cache identical code
in different contexts, leading to a small but consistent improvement
on the benchmarks we track.

* bytecode/UnlinkedCodeBlock.cpp:
(JSC::UnlinkedFunctionExecutable::UnlinkedFunctionExecutable):
* bytecode/UnlinkedCodeBlock.h:
(JSC::UnlinkedFunctionExecutable::functionStartOffset):
(UnlinkedFunctionExecutable):
* parser/ASTBuilder.h:
(ASTBuilder):
(JSC::ASTBuilder::setFunctionStart):
* parser/Nodes.cpp:
* parser/Nodes.h:
(JSC::FunctionBodyNode::setFunctionStart):
(JSC::FunctionBodyNode::functionStart):
(FunctionBodyNode):
* parser/Parser.cpp:
(JSC::::parseFunctionInfo):
* parser/Parser.h:
(JSC::Parser::findCachedFunctionInfo):
* parser/SyntaxChecker.h:
(JSC::SyntaxChecker::setFunctionStart):
* runtime/CodeCache.cpp:
(JSC::CodeCache::generateFunctionCodeBlock):
(JSC::CodeCache::getFunctionCodeBlock):
(JSC::CodeCache::usedFunctionCode):
* runtime/CodeCache.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@136261 268f45cc-cd09-0410-ab3c-d52691b4dbfc