https://bugs.webkit.org/show_bug.cgi?id=95633

Patch by Benjamin Poulain <bpoulain@apple.com> on 2012-09-04
Reviewed by Geoffrey Garen.

This patch improve the use of strings in the JSC runtime.

The initialization of Identifier is left for future patches.

The improvements are the following:
-5% faster to raise one of the modified exception.
-3 times faster to execute Boolean::toString()

Most of the changes are just about using the new methods
for string literals.

With the changes, the binary on x86_64 gets 176 bytes smaller.

* API/JSCallbackObjectFunctions.h:
(JSC::::staticFunctionGetter):
(JSC::::callbackGetter):
* API/JSContextRef.cpp:
(JSContextCreateBacktrace):
* API/JSObjectRef.cpp:
(JSObjectMakeFunctionWithCallback):
* bytecode/CodeBlock.cpp:
(JSC::valueToSourceString):
(JSC::CodeBlock::nameForRegister):
* interpreter/Interpreter.cpp:
(JSC::Interpreter::addStackTraceIfNecessary):
* runtime/ArrayConstructor.cpp:
(JSC::constructArrayWithSizeQuirk):
* runtime/ArrayPrototype.cpp:
(JSC::shift):
(JSC::unshift):
(JSC::arrayProtoFuncPop):
(JSC::arrayProtoFuncReverse):
* runtime/BooleanPrototype.cpp:
(JSC::booleanProtoFuncToString): Instead of instanciating new strings, reuse the
keywords available in SmallStrings. Avoiding the creation of the JSString and StringImpl
makes the method significantly faster.

* runtime/DateConversion.cpp:
(JSC::formatDateTime):
* runtime/DatePrototype.cpp:
(JSC::formatLocaleDate):
(JSC::formateDateInstance):
(JSC::dateProtoFuncToISOString):
Change the way we use snprintf() for clarity and performance.

Instead of allocating one extra byte to put a zero "just in case", we use the size returned
by snprintf().
To prevent any overflow from a programming mistake, we explicitely test for overflow and
return an empty string.

(JSC::dateProtoFuncToJSON):
* runtime/Error.cpp:
(JSC::createNotEnoughArgumentsError):
(JSC::throwTypeError):
(JSC::throwSyntaxError):
* runtime/Error.h:
(JSC::StrictModeTypeErrorFunction::create):
* runtime/ErrorPrototype.cpp:
(JSC::ErrorPrototype::finishCreation):
(JSC::errorProtoFuncToString):
Using a null String is correct because (8) uses jsString(), (9) tests for a length of 0.

* runtime/ExceptionHelpers.cpp:
(JSC::InterruptedExecutionError::defaultValue):
(JSC::TerminatedExecutionError::defaultValue):
(JSC::createStackOverflowError):
(JSC::createOutOfMemoryError):
* runtime/Executable.cpp:
(JSC::EvalExecutable::compileInternal):
(JSC::FunctionExecutable::paramString):
* runtime/FunctionConstructor.cpp:
(JSC::constructFunction):
(JSC::constructFunctionSkippingEvalEnabledCheck):
* runtime/FunctionPrototype.h:
(JSC::FunctionPrototype::create):
Using a null String for the name is correct because InternalFunction uses jsString()
to create the name value.

* runtime/InternalFunction.cpp:
(JSC::InternalFunction::finishCreation):
There is no need to create an empty string for a null string, jsString() handle both
cases as empty JSString.

* runtime/JSArray.cpp:
(JSC::reject):
(JSC::SparseArrayValueMap::put):
(JSC::JSArray::put):
(JSC::JSArray::putByIndexBeyondVectorLength):
(JSC::JSArray::putDirectIndexBeyondVectorLength):
(JSC::JSArray::setLength):
(JSC::JSArray::pop):
(JSC::JSArray::push):
* runtime/JSFunction.cpp:
(JSC::JSFunction::finishCreation): Same issue as InternalFunction::finishCreation.

(JSC::JSFunction::callerGetter):
(JSC::JSFunction::defineOwnProperty):
* runtime/JSGlobalData.cpp:
(JSC::enableAssembler): Use CFSTR() instead of CFStringCreateWithCString().
CFStringCreateWithCString() copy the content and may choose to decode the data.
CFSTR() is much more efficient.

* runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::reset):
JSFunction uses jsString() to create the name, we can use null strings instead
of creating empty strings.

(JSC::JSGlobalObject::createThrowTypeError): ditto.
* runtime/JSGlobalObjectFunctions.cpp:
(JSC::encode):
(JSC::decode):
(JSC::globalFuncEval):
* runtime/JSONObject.cpp:
(JSC::Stringifier::appendStringifiedValue):
(JSC::Stringifier::Holder::appendNextProperty):
(JSC::JSONProtoFuncParse):
(JSC::JSONProtoFuncStringify):
* runtime/JSObject.cpp:
(JSC::JSObject::put):
(JSC::JSObject::defaultValue):
(JSC::JSObject::hasInstance):
(JSC::JSObject::defineOwnProperty):
* runtime/JSString.cpp:
Return an empty JSString to avoid the creation of a temporary empty String.

(JSC::JSRopeString::getIndexSlowCase):
* runtime/JSString.h:
(JSC): Remove the versions of jsNontrivialString() taking a char*. All the callers
have been replaced by calls using ASCIILiteral.

* runtime/JSValue.cpp:
(JSC::JSValue::putToPrimitive):
* runtime/LiteralParser.cpp:
(JSC::::Lexer::lex):
(JSC::::Lexer::lexString):
(JSC::::Lexer::lexNumber):
(JSC::::parse):
* runtime/LiteralParser.h:
(JSC::LiteralParser::getErrorMessage):
* runtime/NumberPrototype.cpp:
(JSC::numberProtoFuncToExponential):
(JSC::numberProtoFuncToFixed):
(JSC::numberProtoFuncToPrecision):
(JSC::numberProtoFuncToString):
* runtime/ObjectConstructor.cpp:
(JSC::objectConstructorGetPrototypeOf):
(JSC::objectConstructorGetOwnPropertyDescriptor):
(JSC::objectConstructorGetOwnPropertyNames):
(JSC::objectConstructorKeys):
(JSC::toPropertyDescriptor):
(JSC::objectConstructorDefineProperty):
(JSC::objectConstructorDefineProperties):
(JSC::objectConstructorCreate):
(JSC::objectConstructorSeal):
(JSC::objectConstructorFreeze):
(JSC::objectConstructorPreventExtensions):
(JSC::objectConstructorIsSealed):
(JSC::objectConstructorIsFrozen):
(JSC::objectConstructorIsExtensible):
* runtime/ObjectPrototype.cpp:
(JSC::objectProtoFuncDefineGetter):
(JSC::objectProtoFuncDefineSetter):
(JSC::objectProtoFuncToString):
* runtime/RegExpConstructor.cpp:
(JSC::constructRegExp):
* runtime/RegExpObject.cpp:
(JSC::reject):
(JSC::regExpObjectSource):
* runtime/RegExpPrototype.cpp:
(JSC::regExpProtoFuncCompile):
* runtime/StringObject.cpp:
(JSC::StringObject::defineOwnProperty):
* runtime/StringPrototype.cpp:
(JSC::jsSpliceSubstrings):
(JSC::jsSpliceSubstringsWithSeparators):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@127505 268f45cc-cd09-0410-ab3c-d52691b4dbfc