Reviewed by Gavin Barraclough.

        Need to support more efficient dispatch of lightweight builtins
        https://bugs.webkit.org/show_bug.cgi?id=38155

        The problem with calling lightweight builtins is that marshalling
        the call from the nitro calling convention to the system calling
        convention is very expensive relative to the cost of the actually
        evaluating the function.  To work around this problem this patch
        adds the ability to define a custom thunk for a builtin.

        This allows us to use high performance custom implementations of
        the common and sensible versions of simple builtins.  This patch
        includes a simple (use of which is currently hardcoded) thunk for
        charCodeAt.

        This adds a JSInterfaceJIT subclass called SpecializedThunkJIT
        that has helper functions to remove (or at least reduce) the need
        to have separate thunk implementations for each JSValue encoding.

        * GNUmakefile.am:
        * JavaScriptCore.pro:
        * JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
        * JavaScriptCore.xcodeproj/project.pbxproj:
          Many project file updates

        * create_hash_table:
          Add thunk generation callbacks to the hash tables, currently
          we hardcode the script to only support charCodeAt

        * jit/JITStubCall.h:
        * jit/JITStubs.cpp:
        (JSC::JITThunks::~JITThunks):
        (JSC::JITThunks::specializedThunk):
        * jit/JITStubs.h:
        * jit/SpecializedThunkJIT.h: Added.
        (JSC::SpecializedThunkJIT::SpecializedThunkJIT):
        (JSC::SpecializedThunkJIT::loadCellArgument):
        (JSC::SpecializedThunkJIT::loadJSStringArgument):
        (JSC::SpecializedThunkJIT::loadInt32Argument):
        (JSC::SpecializedThunkJIT::appendFailure):
        (JSC::SpecializedThunkJIT::returnInt32):
        (JSC::SpecializedThunkJIT::finalize):
        (JSC::SpecializedThunkJIT::argumentToVirtualRegister):
        (JSC::SpecializedThunkJIT::tagReturnAsInt32):
        * jit/ThunkGenerators.cpp: Added.
        (JSC::ThunkHelpers::stringImplDataOffset):
        (JSC::ThunkHelpers::jsStringLengthOffset):
        (JSC::ThunkHelpers::jsStringValueOffset):
        (JSC::charCodeAtThunkGenerator):
        * jit/ThunkGenerators.h: Added.
        * runtime/Executable.h:
        (JSC::NativeExecutable::NativeExecutable):
        * runtime/JSFunction.cpp:
        (JSC::JSFunction::JSFunction):
        * runtime/JSFunction.h:
        * runtime/JSGlobalData.h:
        (JSC::JSGlobalData::getThunk):
        * runtime/JSString.h:
        (JSC::):
        * runtime/JSValue.h:
          Protect some of the JSVALUE32 and JSVALUE32_64 only constants
          and function behind appropriate USE() guards to make it harder
          to use the wrong flags for the target build.
        * runtime/Lookup.cpp:
        (JSC::HashTable::createTable):
        (JSC::setUpStaticFunctionSlot):
        * runtime/Lookup.h:
        (JSC::HashEntry::initialize):
        (JSC::HashEntry::generator):
        (JSC::HashEntry::):
          Make the lookup tables use a specialized thunkGenerator
          if present
        * wtf/text/StringImpl.h:
2010-04-26  Oliver Hunt  <oliver@apple.com>

        Reviewed by Gavin Barraclough.

        Need to support more efficient dispatch of lightweight builtins
        https://bugs.webkit.org/show_bug.cgi?id=38155

        Update bindings generation to include new thunk generator field
        in the property map hash tables.

        * bindings/scripts/CodeGeneratorJS.pm:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@58286 268f45cc-cd09-0410-ab3c-d52691b4dbfc