- speedups, total 12% on JavaScript iBench

        I ran the benchmark under Shark and followed its advice a lot, mainly.

        * kjs/collector.cpp:
        (KJS::Collector::allocate): Take out special case for 0; costing speed but unexercised.
        Use numLiveObjectsAtLastCollect instead of numAllocationsSinceLastCollect so we don't
        have to bump it each time we call allocate. Put numLiveObjects into a local variable to
        cut down on global variable accesses. Make "next" cell pointer be a byte offset rather
        than a pointer so we don't need a special case for NULL. Allow freeList to point to some
        bogus item when the entire block is full rather than going out of our way to make it
        point to NULL.
        (KJS::Collector::markProtectedObjects): Get table size and pointer into locals outside
        the loop to avoid re-loading them over and over again.
        (KJS::Collector::collect): Put numLiveObjects into a local variable to cut down on global
        variable accesses. Make "next" cell pointer be a byte offset as above. Put numLiveObjects
        into a local variable to cut down on global variable accesses. Set numLiveObjectsAtLastCollect
        rather than numAllocationsSinceLastCollect.
        (KJS::Collector::numReferencedObjects): Get table size and pointer into locals outside
        the loop to avoid re-loading them over and over again.
        (KJS::Collector::rootObjectClasses): Ditto.

        * kjs/internal.h: Make Value be a friend of NumberImp so it can construct number objects
        directly, avoiding the conversion from Number to Value.

        * kjs/internal.cpp: (StringImp::toObject): Don't use Object::dynamicCast, because we know
        the thing is an object and we don't want to do all the extra work; just cast directly.

        * kjs/list.cpp: (KJS::List::List): Construct valueRefCount in a way that avoids the need for
        a branch -- in the hot case this just meant avoiding checking a variable we just set to false.

        * kjs/lookup.cpp: (keysMatch): Marked this inline.

        * kjs/nodes.cpp: Disabled KJS_BREAKPOINT, to avoid calling hitStatement all the time.
        (BooleanNode::evaluate): Make a Value directly, rather than making a Boolean which is converted
        into a Value.
        (NumberNode::evaluate): Ditto.
        (StringNode::evaluate): Ditto.
        (ArrayNode::evaluate): Ditto.
        (FunctionCallNode::evaluate): Use new inline baseIfMutable to avoid unnecessary getBase function.
        Also just use a pointer for func, rather than an Object.
        (PostfixNode::evaluate): Change code so that it doesn't make an excess Number, and so that it
        passes a "known to be integer" boolean in, often avoiding a conversion from floating point to
        integer and back.
        (DeleteNode::evaluate): Make a Value directly.
        (TypeOfNode::evaluate): Use new inline baseIfMutable and make Value directly.
        (PrefixNode::evaluate): Change code so that it doesn't make an excess Number, and so that it
        passes a "known to be integer" boolean in, often avoiding a conversion from floating point to
        integer and back.
        (UnaryPlusNode::evaluate): Make a Value directly.
        (NegateNode::evaluate): Change code so that it doesn't make an excess Number, and so that it
        passes a "known to be integer" boolean in, often avoiding a conversion from floating point to
        integer and back.
        (BitwiseNotNode::evaluate): Make a Value directly.
        (LogicalNotNode::evaluate): Ditto.
        (ShiftNode::evaluate): Don't convert to a double before making a Value.
        (RelationalNode::evaluate): Make a Value directly.
        (EqualNode::evaluate): Ditto.
        (BitOperNode::evaluate): Ditto.
        (AssignNode::evaluate): Make a Value directly. Change code so that it passes a "known to be integer"
        boolean in, often avoiding a conversion from floating point to integer and back.
        (VarDeclNode::evaluate): Make a Value directly.
        (ForNode::execute): Remove unused local variable.

        * kjs/operations.h:
        (KJS::isNaN): Inlined.
        (KJS::isInf): Ditto.
        (KJS::isPosInf): Ditto.
        (KJS::isNegInf): Ditto.

        * kjs/operations.cpp: Change isNaN, isInf, isPosInf, and isNegInf to be inlines.
        (KJS::equal): Rewrite to avoid creating values and recursing back into the function.
        (KJS::relation): Rearranged code so that we don't need explicit isNaN checks.
        (KJS::add): Changed code to make Value directly, and so that it passes a "known to be integer"
        boolean in, often avoiding a conversion from floating point to integer and back.
        (KJS::mult): Ditto.

        * kjs/property_map.cpp:
        (KJS::PropertyMap::~PropertyMap): Get size and entries pointer outside loop to avoid
        re-getting them inside the loop.
        (KJS::PropertyMap::clear): Ditto. Clear value pointer in addition to key, so we can just
        look at the value pointer in the mark function.
        (KJS::PropertyMap::get): Get sizeMask and entries pointer outside loop to avoid
        re-getting them inside the loop.
        (KJS::PropertyMap::put): Ditto.
        (KJS::PropertyMap::insert): Ditto.
        (KJS::PropertyMap::remove): Ditto.
        (KJS::PropertyMap::mark): Get size and entries pointer outside loop to avoid
        re-getting them inside the loop. Don't bother checking key for 0, since we already have
        to check value for 0. (Also had to change clear() to set value to 0.)
        (KJS::PropertyMap::addEnumerablesToReferenceList): Get size and entries pointer outside
        loop to avoid re-getting them inside the loop.
        (KJS::PropertyMap::addSparseArrayPropertiesToReferenceList): Ditto.
        (KJS::PropertyMap::save): Ditto.

        - other changes

        * kjs/protected_values.h: Remove unneeded class name qualifiers.

        * kjs/reference.h:
        (KJS::Reference::baseIfMutable): New inline function: replaces isMutable().
        (KJS::Reference::Reference): Inlined.
        * kjs/reference.cpp:
        (KJS::Reference::getValue): Rewrite to not use getBase.
        (KJS::Reference::putValue): Ditto.
        (KJS::Reference::deleteValue): Dittol

        * kjs/simple_number.h:
        (KJS::SimpleNumber::integerFits): Added. For use when the parameter is known to be integral.

        * kjs/string_object.cpp: (StringProtoFuncImp::call): Create the number without first converting
        to double in various cases that involve integers.

        * kjs/ustring.h:
        (KJS::UString::attach): Inlined.
        (KJS::UString::release): Inlined.
        * kjs/ustring.cpp:
        (KJS::UString::find): Get first character outside the loop instead of re-fetching it each time.

        * kjs/value.cpp:
        (Value::Value): Added overloads for all the various specific types of values, so you don't have
        to convert from, say, Number to Value, just to create one.
        (Number::Number): Added an overload that takes a boolean to indicate the number is already
        known to be an integer.

        * kjs/value.h: Added more Value constructors, added a version of toNumber that returns
        a boolean to indicate if the number is known to be an integer (because it was a "simple number").
        (KJS::ValueImp::marked): Inlined.
        (KJS::ValueImp::dispatchType): Inlined.
        (KJS::ValueImp::dispatchToPrimitive): Inlined.
        (KJS::ValueImp::dispatchToBoolean): Inlined.
        (KJS::ValueImp::dispatchToNumber): Inlined.
        (KJS::ValueImp::dispatchToString): Inlined.
        (KJS::ValueImp::dispatchToUInt32): Inlined.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@9033 268f45cc-cd09-0410-ab3c-d52691b4dbfc