Reviewed by Darin and Geoff.

        - Fixed "Stack overflow crash in JavaScript garbage collector mark pass"
        http://bugs.webkit.org/show_bug.cgi?id=12216
        
        Implement mark stack. This version is not suitable for prime time because it makes a
        huge allocation on every collect, and potentially makes marking of detached subtrees
        slow. But it is an 0.4% SunSpider speedup even without much tweaking.
        
        The basic approach is to replace mark() methods with
        markChildren(MarkStack&) methods. Reachable references are pushed
        onto a mark stack (which encapsulates ignoring already-marked
        references). 
        
        Objects are no longer responsible for actually setting their own
        mark bits, the collector does that. This means that for objects on
        the number heap we don't have to call markChildren() at all since
        we know there aren't any.
        
        The mark phase of collect pushes roots onto the mark stack
        and drains it as often as possible.
        
        To make this approach viable requires a constant-size mark stack
        and a slow fallback approach for when the stack size is exceeded,
        plus optimizations to make the required stack small in common
        cases. This should be doable.

        * JavaScriptCore.exp: Export new symbols.
        * JavaScriptCore.xcodeproj/project.pbxproj: Add new file.
        * kjs/collector.cpp:
        (KJS::Collector::heapAllocate):
        (KJS::drainMarkStack): Helper for all of the below.
        (KJS::Collector::markStackObjectsConservatively): Use mark stack.
        (KJS::Collector::markCurrentThreadConservatively): ditto
        (KJS::Collector::markOtherThreadConservatively): ditto
        (KJS::Collector::markProtectedObjects): ditto
        (KJS::Collector::markMainThreadOnlyObjects): ditto
        (KJS::Collector::collect): ditto
        * kjs/collector.h:
        (KJS::Collector::cellMayHaveRefs): Helper for MarkStack.

        * kjs/MarkStack.h: Added. The actual mark stack implementation.
        (KJS::MarkStack::push):
        (KJS::MarkStack::pushAtom):
        (KJS::MarkStack::pop):
        (KJS::MarkStack::isEmpty):
        (KJS::MarkStack::reserveCapacity):

        Changed mark() methods to markChildren() methods:
        
        * kjs/ExecState.cpp:
        (KJS::ExecState::markChildren):
        * kjs/ExecState.h:
        * kjs/JSWrapperObject.cpp:
        (KJS::JSWrapperObject::markChildren):
        * kjs/JSWrapperObject.h:
        * kjs/array_instance.cpp:
        (KJS::ArrayInstance::markChildren):
        * kjs/array_instance.h:
        * kjs/bool_object.cpp:
        (BooleanInstance::markChildren):
        * kjs/bool_object.h:
        * kjs/error_object.cpp:
        * kjs/error_object.h:
        * kjs/function.cpp:
        (KJS::FunctionImp::markChildren):
        (KJS::Arguments::Arguments):
        (KJS::Arguments::markChildren):
        (KJS::ActivationImp::markChildren):
        * kjs/function.h:
        * kjs/internal.cpp:
        (KJS::GetterSetterImp::markChildren):
        * kjs/interpreter.cpp:
        (KJS::Interpreter::markRoots):
        * kjs/interpreter.h:
        * kjs/list.cpp:
        (KJS::List::markProtectedListsSlowCase):
        * kjs/list.h:
        (KJS::List::markProtectedLists):
        * kjs/object.cpp:
        (KJS::JSObject::markChildren):
        * kjs/object.h:
        (KJS::ScopeChain::markChildren):
        * kjs/property_map.cpp:
        (KJS::PropertyMap::markChildren):
        * kjs/property_map.h:
        * kjs/scope_chain.h:
        * kjs/string_object.cpp:
        (KJS::StringInstance::markChildren):
        * kjs/string_object.h:

JavaScriptGlue:

        Reviewed by Darin and Geoff.

        Fixups for JavaScriptCore mark stack.

        * JSObject.cpp:
        (JSUserObject::Mark):
        * JSObject.h:
        * JSValueWrapper.cpp:
        (JSValueWrapper::JSObjectMark):
        * JSValueWrapper.h:
        * UserObjectImp.cpp:
        * UserObjectImp.h:

WebCore:

        Reviewed by Darin and Geoff.

        Implement mark stack. This version is not suitable for prime time because it makes a
        huge allocation on every collect, and potentially makes marking of detached subtrees
        slow. But it is a .2% - .4% speedup even without much tweaking.

        I replaced mark() methods with markChildren() as usual. One
        optimization that is lost is avoiding walking detached DOM
        subtrees more than once to mark them; since marking is not
        recursive there's no obvious way to bracket operation on the tree
        any more.

        * bindings/js/JSDocumentCustom.cpp:
        (WebCore::JSDocument::markChildren):
        * bindings/js/JSNodeCustom.cpp:
        (WebCore::JSNode::markChildren):
        * bindings/js/JSNodeFilterCondition.cpp:
        * bindings/js/JSNodeFilterCondition.h:
        * bindings/js/JSNodeFilterCustom.cpp:
        (WebCore::JSNodeFilter::markChildren):
        * bindings/js/JSNodeIteratorCustom.cpp:
        (WebCore::JSNodeIterator::markChildren):
        * bindings/js/JSTreeWalkerCustom.cpp:
        (WebCore::JSTreeWalker::markChildren):
        * bindings/js/JSXMLHttpRequest.cpp:
        (KJS::JSXMLHttpRequest::markChildren):
        * bindings/js/JSXMLHttpRequest.h:
        * bindings/js/kjs_binding.cpp:
        (KJS::ScriptInterpreter::markDOMNodesForDocument):
        * bindings/js/kjs_binding.h:
        * bindings/js/kjs_events.cpp:
        (WebCore::JSUnprotectedEventListener::markChildren):
        * bindings/js/kjs_events.h:
        * bindings/js/kjs_window.cpp:
        (KJS::Window::markChildren):
        * bindings/js/kjs_window.h:
        * bindings/scripts/CodeGeneratorJS.pm:
        * dom/Node.cpp:
        (WebCore::Node::Node):
        * dom/Node.h:
        * dom/NodeFilter.h:
        * dom/NodeFilterCondition.h:

LayoutTests:

        Not reviewed.
        
        - Test cases for "Stack overflow crash in JavaScript garbage collector mark pass"
        http://bugs.webkit.org/show_bug.cgi?id=12216

        I have fixed this with the mark stack work.
        
        * fast/js/gc-breadth-2-expected.txt: Added.
        * fast/js/gc-breadth-2.html: Added.
        * fast/js/gc-breadth-expected.txt: Added.
        * fast/js/gc-breadth.html: Added.
        * fast/js/gc-depth-expected.txt: Added.
        * fast/js/gc-depth.html: Added.
        * fast/js/resources/gc-breadth-2.js: Added.
        * fast/js/resources/gc-breadth.js: Added.
        * fast/js/resources/gc-depth.js: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@28106 268f45cc-cd09-0410-ab3c-d52691b4dbfc