From 1bf1084f2b10c3b47fd1a588d85d21ed0eb41d0c Mon Sep 17 00:00:00 2001
From: Lorry Tar Creator <lorry-tar-importer@lorry>
Date: Tue, 27 Jun 2017 06:07:23 +0000
Subject: webkitgtk-2.16.5

---
 Source/JavaScriptCore/jsc.cpp | 3785 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 3325 insertions(+), 460 deletions(-)

(limited to 'Source/JavaScriptCore/jsc.cpp')

diff --git a/Source/JavaScriptCore/jsc.cpp b/Source/JavaScriptCore/jsc.cpp
index 40784b494..aedf42e17 100644
--- a/Source/JavaScriptCore/jsc.cpp
+++ b/Source/JavaScriptCore/jsc.cpp
@@ -1,6 +1,6 @@
 /*
  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
- *  Copyright (C) 2004, 2005, 2006, 2007, 2008, 2012, 2013 Apple Inc. All rights reserved.
+ *  Copyright (C) 2004-2017 Apple Inc. All rights reserved.
  *  Copyright (C) 2006 Bjoern Graf (bjoern.graf@gmail.com)
  *
  *  This library is free software; you can redistribute it and/or
@@ -22,38 +22,74 @@
 
 #include "config.h"
 
-#include "APIShims.h"
+#include "ArrayBuffer.h"
+#include "ArrayPrototype.h"
+#include "BuiltinExecutableCreator.h"
+#include "BuiltinNames.h"
 #include "ButterflyInlines.h"
-#include "BytecodeGenerator.h"
-#include "CallFrameInlines.h"
+#include "CodeBlock.h"
 #include "Completion.h"
-#include "CopiedSpaceInlines.h"
+#include "DOMJITGetterSetter.h"
+#include "DOMJITPatchpoint.h"
+#include "DOMJITPatchpointParams.h"
+#include "Disassembler.h"
+#include "Exception.h"
 #include "ExceptionHelpers.h"
-#include "HeapStatistics.h"
+#include "GetterSetter.h"
+#include "HeapProfiler.h"
+#include "HeapSnapshotBuilder.h"
 #include "InitializeThreading.h"
 #include "Interpreter.h"
+#include "JIT.h"
 #include "JSArray.h"
 #include "JSArrayBuffer.h"
+#include "JSCInlines.h"
 #include "JSFunction.h"
+#include "JSInternalPromise.h"
+#include "JSInternalPromiseDeferred.h"
 #include "JSLock.h"
+#include "JSModuleLoader.h"
+#include "JSNativeStdFunction.h"
+#include "JSONObject.h"
 #include "JSProxy.h"
+#include "JSSourceCode.h"
 #include "JSString.h"
-#include "Operations.h"
-#include "SamplingTool.h"
+#include "JSTypedArrays.h"
+#include "JSWebAssemblyCallee.h"
+#include "LLIntData.h"
+#include "LLIntThunks.h"
+#include "ObjectConstructor.h"
+#include "ParserError.h"
+#include "ProfilerDatabase.h"
+#include "ProtoCallFrame.h"
+#include "ReleaseHeapAccessScope.h"
+#include "SamplingProfiler.h"
+#include "ShadowChicken.h"
 #include "StackVisitor.h"
+#include "StructureInlines.h"
 #include "StructureRareDataInlines.h"
+#include "SuperSampler.h"
 #include "TestRunnerUtils.h"
+#include "TypeProfilerLog.h"
+#include "WasmPlan.h"
+#include "WasmMemory.h"
+#include <locale.h>
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <thread>
+#include <type_traits>
+#include <wtf/CommaPrinter.h>
 #include <wtf/CurrentTime.h>
 #include <wtf/MainThread.h>
+#include <wtf/NeverDestroyed.h>
 #include <wtf/StringPrintStream.h>
 #include <wtf/text/StringBuilder.h>
 
-#if !OS(WINDOWS)
+#if OS(WINDOWS)
+#include <direct.h>
+#else
 #include <unistd.h>
 #endif
 
@@ -74,7 +110,7 @@
 #include <signal.h>
 #endif
 
-#if COMPILER(MSVC) && !OS(WINCE)
+#if COMPILER(MSVC)
 #include <crtdbg.h>
 #include <mmsystem.h>
 #include <windows.h>
@@ -85,457 +121,3072 @@
 #include <arm/arch.h>
 #endif
 
-#if PLATFORM(EFL)
-#include <Ecore.h>
+#if !defined(PATH_MAX)
+#define PATH_MAX 4096
 #endif
 
 using namespace JSC;
 using namespace WTF;
 
-static bool fillBufferWithContentsOfFile(const String& fileName, Vector<char>& buffer);
+namespace {
 
-static EncodedJSValue JSC_HOST_CALL functionPrint(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionDebug(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionDescribe(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionJSCStack(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionGC(ExecState*);
-#ifndef NDEBUG
-static EncodedJSValue JSC_HOST_CALL functionReleaseExecutableMemory(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionDumpCallFrame(ExecState*);
+NO_RETURN_WITH_VALUE static void jscExit(int status)
+{
+    waitForAsynchronousDisassembly();
+    
+#if ENABLE(DFG_JIT)
+    if (DFG::isCrashing()) {
+        for (;;) {
+#if OS(WINDOWS)
+            Sleep(1000);
+#else
+            pause();
 #endif
-static EncodedJSValue JSC_HOST_CALL functionVersion(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionRun(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionLoad(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionReadFile(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionCheckSyntax(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionReadline(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionPreciseTime(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionNeverInlineFunction(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionNumberOfDFGCompiles(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionTransferArrayBuffer(ExecState*);
-static NO_RETURN_WITH_VALUE EncodedJSValue JSC_HOST_CALL functionQuit(ExecState*);
+        }
+    }
+#endif // ENABLE(DFG_JIT)
+    exit(status);
+}
 
-#if ENABLE(SAMPLING_FLAGS)
-static EncodedJSValue JSC_HOST_CALL functionSetSamplingFlags(ExecState*);
-static EncodedJSValue JSC_HOST_CALL functionClearSamplingFlags(ExecState*);
-#endif
+class Element;
+class ElementHandleOwner;
+class Masuqerader;
+class Root;
+class RuntimeArray;
 
-struct Script {
-    bool isFile;
-    char* argument;
+class Element : public JSNonFinalObject {
+public:
+    Element(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
 
-    Script(bool isFile, char *argument)
-        : isFile(isFile)
-        , argument(argument)
+    typedef JSNonFinalObject Base;
+
+    Root* root() const { return m_root.get(); }
+    void setRoot(VM& vm, Root* root) { m_root.set(vm, this, root); }
+
+    static Element* create(VM& vm, JSGlobalObject* globalObject, Root* root)
     {
+        Structure* structure = createStructure(vm, globalObject, jsNull());
+        Element* element = new (NotNull, allocateCell<Element>(vm.heap, sizeof(Element))) Element(vm, structure);
+        element->finishCreation(vm, root);
+        return element;
     }
-};
 
-class CommandLine {
-public:
-    CommandLine(int argc, char** argv)
-        : m_interactive(false)
-        , m_dump(false)
-        , m_exitCode(false)
-        , m_profile(false)
+    void finishCreation(VM&, Root*);
+
+    static void visitChildren(JSCell* cell, SlotVisitor& visitor)
     {
-        parseArguments(argc, argv);
+        Element* thisObject = jsCast<Element*>(cell);
+        ASSERT_GC_OBJECT_INHERITS(thisObject, info());
+        Base::visitChildren(thisObject, visitor);
+        visitor.append(thisObject->m_root);
     }
 
-    bool m_interactive;
-    bool m_dump;
-    bool m_exitCode;
-    Vector<Script> m_scripts;
-    Vector<String> m_arguments;
-    bool m_profile;
-    String m_profilerOutput;
+    static ElementHandleOwner* handleOwner();
 
-    void parseArguments(int, char**);
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
+    }
+
+    DECLARE_INFO;
+
+private:
+    WriteBarrier<Root> m_root;
 };
 
-static const char interactivePrompt[] = ">>> ";
+class ElementHandleOwner : public WeakHandleOwner {
+public:
+    bool isReachableFromOpaqueRoots(Handle<JSC::Unknown> handle, void*, SlotVisitor& visitor) override
+    {
+        Element* element = jsCast<Element*>(handle.slot()->asCell());
+        return visitor.containsOpaqueRoot(element->root());
+    }
+};
 
-class StopWatch {
+class Masquerader : public JSNonFinalObject {
 public:
-    void start();
-    void stop();
-    long getElapsedMS(); // call stop() first
+    Masquerader(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
 
-private:
-    double m_startTime;
-    double m_stopTime;
+    typedef JSNonFinalObject Base;
+    static const unsigned StructureFlags = Base::StructureFlags | JSC::MasqueradesAsUndefined;
+
+    static Masquerader* create(VM& vm, JSGlobalObject* globalObject)
+    {
+        globalObject->masqueradesAsUndefinedWatchpoint()->fireAll(vm, "Masquerading object allocated");
+        Structure* structure = createStructure(vm, globalObject, jsNull());
+        Masquerader* result = new (NotNull, allocateCell<Masquerader>(vm.heap, sizeof(Masquerader))) Masquerader(vm, structure);
+        result->finishCreation(vm);
+        return result;
+    }
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
+    }
+
+    DECLARE_INFO;
 };
 
-void StopWatch::start()
-{
-    m_startTime = monotonicallyIncreasingTime();
-}
+class Root : public JSDestructibleObject {
+public:
+    Root(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
 
-void StopWatch::stop()
-{
-    m_stopTime = monotonicallyIncreasingTime();
-}
+    Element* element()
+    {
+        return m_element.get();
+    }
 
-long StopWatch::getElapsedMS()
-{
-    return static_cast<long>((m_stopTime - m_startTime) * 1000);
-}
+    void setElement(Element* element)
+    {
+        Weak<Element> newElement(element, Element::handleOwner());
+        m_element.swap(newElement);
+    }
 
-class GlobalObject : public JSGlobalObject {
-private:
-    GlobalObject(VM&, Structure*);
+    static Root* create(VM& vm, JSGlobalObject* globalObject)
+    {
+        Structure* structure = createStructure(vm, globalObject, jsNull());
+        Root* root = new (NotNull, allocateCell<Root>(vm.heap, sizeof(Root))) Root(vm, structure);
+        root->finishCreation(vm);
+        return root;
+    }
 
-public:
-    typedef JSGlobalObject Base;
+    typedef JSDestructibleObject Base;
 
-    static GlobalObject* create(VM& vm, Structure* structure, const Vector<String>& arguments)
+    DECLARE_INFO;
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
     {
-        GlobalObject* object = new (NotNull, allocateCell<GlobalObject>(vm.heap)) GlobalObject(vm, structure);
-        object->finishCreation(vm, arguments);
-        vm.heap.addFinalizer(object, destroy);
-        object->setGlobalThis(vm, JSProxy::create(vm, JSProxy::createStructure(vm, object, object->prototype()), object));
-        return object;
+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
     }
 
-    static const bool needsDestruction = false;
+    static void visitChildren(JSCell* thisObject, SlotVisitor& visitor)
+    {
+        Base::visitChildren(thisObject, visitor);
+        visitor.addOpaqueRoot(thisObject);
+    }
+
+private:
+    Weak<Element> m_element;
+};
+
+class ImpureGetter : public JSNonFinalObject {
+public:
+    ImpureGetter(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
 
     DECLARE_INFO;
-    static const GlobalObjectMethodTable s_globalObjectMethodTable;
+    typedef JSNonFinalObject Base;
+    static const unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::OverridesGetOwnPropertySlot;
 
-    static Structure* createStructure(VM& vm, JSValue prototype)
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
     {
-        return Structure::create(vm, 0, prototype, TypeInfo(GlobalObjectType, StructureFlags), info());
+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
     }
 
-    static bool javaScriptExperimentsEnabled(const JSGlobalObject*) { return true; }
+    static ImpureGetter* create(VM& vm, Structure* structure, JSObject* delegate)
+    {
+        ImpureGetter* getter = new (NotNull, allocateCell<ImpureGetter>(vm.heap, sizeof(ImpureGetter))) ImpureGetter(vm, structure);
+        getter->finishCreation(vm, delegate);
+        return getter;
+    }
 
-protected:
-    void finishCreation(VM& vm, const Vector<String>& arguments)
+    void finishCreation(VM& vm, JSObject* delegate)
     {
         Base::finishCreation(vm);
+        if (delegate)
+            m_delegate.set(vm, this, delegate);
+    }
+
+    static bool getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName name, PropertySlot& slot)
+    {
+        VM& vm = exec->vm();
+        auto scope = DECLARE_THROW_SCOPE(vm);
+        ImpureGetter* thisObject = jsCast<ImpureGetter*>(object);
         
-        addFunction(vm, "debug", functionDebug, 1);
-        addFunction(vm, "describe", functionDescribe, 1);
-        addFunction(vm, "print", functionPrint, 1);
-        addFunction(vm, "quit", functionQuit, 0);
-        addFunction(vm, "gc", functionGC, 0);
-#ifndef NDEBUG
-        addFunction(vm, "dumpCallFrame", functionDumpCallFrame, 0);
-        addFunction(vm, "releaseExecutableMemory", functionReleaseExecutableMemory, 0);
-#endif
-        addFunction(vm, "version", functionVersion, 1);
-        addFunction(vm, "run", functionRun, 1);
-        addFunction(vm, "load", functionLoad, 1);
-        addFunction(vm, "readFile", functionReadFile, 1);
-        addFunction(vm, "checkSyntax", functionCheckSyntax, 1);
-        addFunction(vm, "jscStack", functionJSCStack, 1);
-        addFunction(vm, "readline", functionReadline, 0);
-        addFunction(vm, "preciseTime", functionPreciseTime, 0);
-        addFunction(vm, "neverInlineFunction", functionNeverInlineFunction, 1);
-        addFunction(vm, "noInline", functionNeverInlineFunction, 1);
-        addFunction(vm, "numberOfDFGCompiles", functionNumberOfDFGCompiles, 1);
-        addFunction(vm, "transferArrayBuffer", functionTransferArrayBuffer, 1);
-#if ENABLE(SAMPLING_FLAGS)
-        addFunction(vm, "setSamplingFlags", functionSetSamplingFlags, 1);
-        addFunction(vm, "clearSamplingFlags", functionClearSamplingFlags, 1);
-#endif
-        
-        JSArray* array = constructEmptyArray(globalExec(), 0);
-        for (size_t i = 0; i < arguments.size(); ++i)
-            array->putDirectIndex(globalExec(), i, jsString(globalExec(), arguments[i]));
-        putDirect(vm, Identifier(globalExec(), "arguments"), array);
+        if (thisObject->m_delegate) {
+            if (thisObject->m_delegate->getPropertySlot(exec, name, slot))
+                return true;
+            RETURN_IF_EXCEPTION(scope, false);
+        }
+
+        return Base::getOwnPropertySlot(object, exec, name, slot);
     }
 
-    void addFunction(VM& vm, const char* name, NativeFunction function, unsigned arguments)
+    static void visitChildren(JSCell* cell, SlotVisitor& visitor)
     {
-        Identifier identifier(&vm, name);
-        putDirect(vm, identifier, JSFunction::create(vm, this, arguments, identifier.string(), function));
+        Base::visitChildren(cell, visitor);
+        ImpureGetter* thisObject = jsCast<ImpureGetter*>(cell);
+        visitor.append(thisObject->m_delegate);
     }
-    
-    void addConstructableFunction(VM& vm, const char* name, NativeFunction function, unsigned arguments)
+
+    void setDelegate(VM& vm, JSObject* delegate)
     {
-        Identifier identifier(&vm, name);
-        putDirect(vm, identifier, JSFunction::create(vm, this, arguments, identifier.string(), function, NoIntrinsic, function));
+        m_delegate.set(vm, this, delegate);
     }
+
+private:
+    WriteBarrier<JSObject> m_delegate;
 };
 
-const ClassInfo GlobalObject::s_info = { "global", &JSGlobalObject::s_info, 0, ExecState::globalObjectTable, CREATE_METHOD_TABLE(GlobalObject) };
-const GlobalObjectMethodTable GlobalObject::s_globalObjectMethodTable = { &allowsAccessFrom, &supportsProfiling, &supportsRichSourceInfo, &shouldInterruptScript, &javaScriptExperimentsEnabled, 0, &shouldInterruptScriptBeforeTimeout };
+class CustomGetter : public JSNonFinalObject {
+public:
+    CustomGetter(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
+
+    DECLARE_INFO;
+    typedef JSNonFinalObject Base;
+    static const unsigned StructureFlags = Base::StructureFlags | JSC::OverridesGetOwnPropertySlot;
 
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
+    }
 
-GlobalObject::GlobalObject(VM& vm, Structure* structure)
-    : JSGlobalObject(vm, structure, &s_globalObjectMethodTable)
-{
-}
+    static CustomGetter* create(VM& vm, Structure* structure)
+    {
+        CustomGetter* getter = new (NotNull, allocateCell<CustomGetter>(vm.heap, sizeof(CustomGetter))) CustomGetter(vm, structure);
+        getter->finishCreation(vm);
+        return getter;
+    }
 
-static inline String stringFromUTF(const char* utf8)
-{
-    // Find the the first non-ascii character, or nul.
-    const char* pos = utf8;
-    while (*pos > 0)
-        pos++;
-    size_t asciiLength = pos - utf8;
-    
-    // Fast case - string is all ascii.
-    if (!*pos)
-        return String(utf8, asciiLength);
-    
-    // Slow case - contains non-ascii characters, use fromUTF8WithLatin1Fallback.
-    ASSERT(*pos < 0);
-    ASSERT(strlen(utf8) == asciiLength + strlen(pos));
-    return String::fromUTF8WithLatin1Fallback(utf8, asciiLength + strlen(pos));
-}
+    static bool getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
+    {
+        CustomGetter* thisObject = jsCast<CustomGetter*>(object);
+        if (propertyName == PropertyName(Identifier::fromString(exec, "customGetter"))) {
+            slot.setCacheableCustom(thisObject, DontDelete | ReadOnly | DontEnum, thisObject->customGetter);
+            return true;
+        }
+        return JSObject::getOwnPropertySlot(thisObject, exec, propertyName, slot);
+    }
 
-static inline SourceCode jscSource(const char* utf8, const String& filename)
-{
-    String str = stringFromUTF(utf8);
-    return makeSource(str, filename);
-}
+private:
+    static EncodedJSValue customGetter(ExecState* exec, EncodedJSValue thisValue, PropertyName)
+    {
+        VM& vm = exec->vm();
+        auto scope = DECLARE_THROW_SCOPE(vm);
+
+        CustomGetter* thisObject = jsDynamicCast<CustomGetter*>(vm, JSValue::decode(thisValue));
+        if (!thisObject)
+            return throwVMTypeError(exec, scope);
+        bool shouldThrow = thisObject->get(exec, PropertyName(Identifier::fromString(exec, "shouldThrow"))).toBoolean(exec);
+        if (shouldThrow)
+            return throwVMTypeError(exec, scope);
+        return JSValue::encode(jsNumber(100));
+    }
+};
 
-EncodedJSValue JSC_HOST_CALL functionPrint(ExecState* exec)
-{
-    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
-        if (i)
-            putchar(' ');
+class RuntimeArray : public JSArray {
+public:
+    typedef JSArray Base;
+    static const unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesGetPropertyNames;
 
-        printf("%s", exec->uncheckedArgument(i).toString(exec)->value(exec).utf8().data());
+    static RuntimeArray* create(ExecState* exec)
+    {
+        VM& vm = exec->vm();
+        JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+        Structure* structure = createStructure(vm, globalObject, createPrototype(vm, globalObject));
+        RuntimeArray* runtimeArray = new (NotNull, allocateCell<RuntimeArray>(*exec->heap())) RuntimeArray(exec, structure);
+        runtimeArray->finishCreation(exec);
+        vm.heap.addFinalizer(runtimeArray, destroy);
+        return runtimeArray;
     }
 
-    putchar('\n');
-    fflush(stdout);
-    return JSValue::encode(jsUndefined());
-}
+    ~RuntimeArray() { }
 
-#ifndef NDEBUG
-EncodedJSValue JSC_HOST_CALL functionDumpCallFrame(ExecState* exec)
-{
-    if (!exec->callerFrame()->isVMEntrySentinel())
-        exec->vm().interpreter->dumpCallFrame(exec->callerFrame());
-    return JSValue::encode(jsUndefined());
-}
-#endif
+    static void destroy(JSCell* cell)
+    {
+        static_cast<RuntimeArray*>(cell)->RuntimeArray::~RuntimeArray();
+    }
 
-EncodedJSValue JSC_HOST_CALL functionDebug(ExecState* exec)
-{
-    fprintf(stderr, "--> %s\n", exec->argument(0).toString(exec)->value(exec).utf8().data());
-    return JSValue::encode(jsUndefined());
-}
+    static const bool needsDestruction = false;
 
-EncodedJSValue JSC_HOST_CALL functionDescribe(ExecState* exec)
-{
-    fprintf(stderr, "--> %s\n", toCString(exec->argument(0)).data());
-    return JSValue::encode(jsUndefined());
-}
+    static bool getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
+    {
+        RuntimeArray* thisObject = jsCast<RuntimeArray*>(object);
+        if (propertyName == exec->propertyNames().length) {
+            slot.setCacheableCustom(thisObject, DontDelete | ReadOnly | DontEnum, thisObject->lengthGetter);
+            return true;
+        }
 
-class FunctionJSCStackFunctor {
-public:
-    FunctionJSCStackFunctor(StringBuilder& trace)
-        : m_trace(trace)
+        std::optional<uint32_t> index = parseIndex(propertyName);
+        if (index && index.value() < thisObject->getLength()) {
+            slot.setValue(thisObject, DontDelete | DontEnum, jsNumber(thisObject->m_vector[index.value()]));
+            return true;
+        }
+
+        return JSObject::getOwnPropertySlot(thisObject, exec, propertyName, slot);
+    }
+
+    static bool getOwnPropertySlotByIndex(JSObject* object, ExecState* exec, unsigned index, PropertySlot& slot)
     {
+        RuntimeArray* thisObject = jsCast<RuntimeArray*>(object);
+        if (index < thisObject->getLength()) {
+            slot.setValue(thisObject, DontDelete | DontEnum, jsNumber(thisObject->m_vector[index]));
+            return true;
+        }
+
+        return JSObject::getOwnPropertySlotByIndex(thisObject, exec, index, slot);
     }
 
-    StackVisitor::Status operator()(StackVisitor& visitor)
+    static NO_RETURN_DUE_TO_CRASH bool put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&)
     {
-        m_trace.append(String::format("    %zu   %s\n", visitor->index(), visitor->toString().utf8().data()));
-        return StackVisitor::Continue;
+        RELEASE_ASSERT_NOT_REACHED();
     }
 
-private:
-    StringBuilder& m_trace;
-};
+    static NO_RETURN_DUE_TO_CRASH bool deleteProperty(JSCell*, ExecState*, PropertyName)
+    {
+        RELEASE_ASSERT_NOT_REACHED();
+    }
 
-EncodedJSValue JSC_HOST_CALL functionJSCStack(ExecState* exec)
-{
-    StringBuilder trace;
-    trace.appendLiteral("--> Stack trace:\n");
+    unsigned getLength() const { return m_vector.size(); }
 
-    FunctionJSCStackFunctor functor(trace);
-    exec->iterate(functor);
-    fprintf(stderr, "%s", trace.toString().utf8().data());
-    return JSValue::encode(jsUndefined());
-}
+    DECLARE_INFO;
 
-EncodedJSValue JSC_HOST_CALL functionGC(ExecState* exec)
-{
-    JSLockHolder lock(exec);
-    exec->heap()->collectAllGarbage();
-    return JSValue::encode(jsUndefined());
-}
+    static ArrayPrototype* createPrototype(VM&, JSGlobalObject* globalObject)
+    {
+        return globalObject->arrayPrototype();
+    }
 
-#ifndef NDEBUG
-EncodedJSValue JSC_HOST_CALL functionReleaseExecutableMemory(ExecState* exec)
-{
-    JSLockHolder lock(exec);
-    exec->vm().releaseExecutableMemory();
-    return JSValue::encode(jsUndefined());
-}
-#endif
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(DerivedArrayType, StructureFlags), info(), ArrayClass);
+    }
 
-EncodedJSValue JSC_HOST_CALL functionVersion(ExecState*)
-{
+protected:
+    void finishCreation(ExecState* exec)
+    {
+        VM& vm = exec->vm();
+        Base::finishCreation(vm);
+        ASSERT(inherits(vm, info()));
+
+        for (size_t i = 0; i < exec->argumentCount(); i++)
+            m_vector.append(exec->argument(i).toInt32(exec));
+    }
+
+private:
+    RuntimeArray(ExecState* exec, Structure* structure)
+        : JSArray(exec->vm(), structure, 0)
+    {
+    }
+
+    static EncodedJSValue lengthGetter(ExecState* exec, EncodedJSValue thisValue, PropertyName)
+    {
+        VM& vm = exec->vm();
+        auto scope = DECLARE_THROW_SCOPE(vm);
+
+        RuntimeArray* thisObject = jsDynamicCast<RuntimeArray*>(vm, JSValue::decode(thisValue));
+        if (!thisObject)
+            return throwVMTypeError(exec, scope);
+        return JSValue::encode(jsNumber(thisObject->getLength()));
+    }
+
+    Vector<int> m_vector;
+};
+
+class SimpleObject : public JSNonFinalObject {
+public:
+    SimpleObject(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
+
+    typedef JSNonFinalObject Base;
+    static const bool needsDestruction = false;
+
+    static SimpleObject* create(VM& vm, JSGlobalObject* globalObject)
+    {
+        Structure* structure = createStructure(vm, globalObject, jsNull());
+        SimpleObject* simpleObject = new (NotNull, allocateCell<SimpleObject>(vm.heap, sizeof(SimpleObject))) SimpleObject(vm, structure);
+        simpleObject->finishCreation(vm);
+        return simpleObject;
+    }
+
+    static void visitChildren(JSCell* cell, SlotVisitor& visitor)
+    {
+        SimpleObject* thisObject = jsCast<SimpleObject*>(cell);
+        ASSERT_GC_OBJECT_INHERITS(thisObject, info());
+        Base::visitChildren(thisObject, visitor);
+        visitor.append(thisObject->m_hiddenValue);
+    }
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
+    }
+
+    JSValue hiddenValue()
+    {
+        return m_hiddenValue.get();
+    }
+
+    void setHiddenValue(VM& vm, JSValue value)
+    {
+        ASSERT(value.isCell());
+        m_hiddenValue.set(vm, this, value);
+    }
+
+    DECLARE_INFO;
+
+private:
+    WriteBarrier<JSC::Unknown> m_hiddenValue;
+};
+
+class DOMJITNode : public JSNonFinalObject {
+public:
+    DOMJITNode(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
+
+    DECLARE_INFO;
+    typedef JSNonFinalObject Base;
+    static const unsigned StructureFlags = Base::StructureFlags;
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(JSC::JSType(LastJSCObjectType + 1), StructureFlags), info());
+    }
+
+#if ENABLE(JIT)
+    static Ref<DOMJIT::Patchpoint> checkDOMJITNode()
+    {
+        Ref<DOMJIT::Patchpoint> patchpoint = DOMJIT::Patchpoint::create();
+        patchpoint->setGenerator([=](CCallHelpers& jit, DOMJIT::PatchpointParams& params) {
+            CCallHelpers::JumpList failureCases;
+            failureCases.append(jit.branch8(
+                CCallHelpers::NotEqual,
+                CCallHelpers::Address(params[0].gpr(), JSCell::typeInfoTypeOffset()),
+                CCallHelpers::TrustedImm32(JSC::JSType(LastJSCObjectType + 1))));
+            return failureCases;
+        });
+        return patchpoint;
+    }
+#endif
+
+    static DOMJITNode* create(VM& vm, Structure* structure)
+    {
+        DOMJITNode* getter = new (NotNull, allocateCell<DOMJITNode>(vm.heap, sizeof(DOMJITNode))) DOMJITNode(vm, structure);
+        getter->finishCreation(vm);
+        return getter;
+    }
+
+    int32_t value() const
+    {
+        return m_value;
+    }
+
+    static ptrdiff_t offsetOfValue() { return OBJECT_OFFSETOF(DOMJITNode, m_value); }
+
+private:
+    int32_t m_value { 42 };
+};
+
+class DOMJITGetter : public DOMJITNode {
+public:
+    DOMJITGetter(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
+
+    DECLARE_INFO;
+    typedef DOMJITNode Base;
+    static const unsigned StructureFlags = Base::StructureFlags;
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(JSC::JSType(LastJSCObjectType + 1), StructureFlags), info());
+    }
+
+    static DOMJITGetter* create(VM& vm, Structure* structure)
+    {
+        DOMJITGetter* getter = new (NotNull, allocateCell<DOMJITGetter>(vm.heap, sizeof(DOMJITGetter))) DOMJITGetter(vm, structure);
+        getter->finishCreation(vm);
+        return getter;
+    }
+
+    class DOMJITNodeDOMJIT : public DOMJIT::GetterSetter {
+    public:
+        DOMJITNodeDOMJIT()
+            : DOMJIT::GetterSetter(DOMJITGetter::customGetter, nullptr, DOMJITNode::info(), SpecInt32Only)
+        {
+        }
+
+#if ENABLE(JIT)
+        Ref<DOMJIT::Patchpoint> checkDOM() override
+        {
+            return DOMJITNode::checkDOMJITNode();
+        }
+
+        static EncodedJSValue JIT_OPERATION slowCall(ExecState* exec, void* pointer)
+        {
+            NativeCallFrameTracer tracer(&exec->vm(), exec);
+            return JSValue::encode(jsNumber(static_cast<DOMJITGetter*>(pointer)->value()));
+        }
+
+        Ref<DOMJIT::CallDOMGetterPatchpoint> callDOMGetter() override
+        {
+            Ref<DOMJIT::CallDOMGetterPatchpoint> patchpoint = DOMJIT::CallDOMGetterPatchpoint::create();
+            patchpoint->requireGlobalObject = false;
+            patchpoint->setGenerator([=](CCallHelpers& jit, DOMJIT::PatchpointParams& params) {
+                JSValueRegs results = params[0].jsValueRegs();
+                GPRReg dom = params[1].gpr();
+                params.addSlowPathCall(jit.jump(), jit, slowCall, results, dom);
+                return CCallHelpers::JumpList();
+
+            });
+            return patchpoint;
+        }
+#endif
+    };
+
+    static DOMJIT::GetterSetter* domJITNodeGetterSetter()
+    {
+        static NeverDestroyed<DOMJITNodeDOMJIT> graph;
+        return &graph.get();
+    }
+
+private:
+    void finishCreation(VM& vm)
+    {
+        Base::finishCreation(vm);
+        DOMJIT::GetterSetter* domJIT = domJITNodeGetterSetter();
+        CustomGetterSetter* customGetterSetter = CustomGetterSetter::create(vm, domJIT->getter(), domJIT->setter(), domJIT);
+        putDirectCustomAccessor(vm, Identifier::fromString(&vm, "customGetter"), customGetterSetter, ReadOnly | CustomAccessor);
+    }
+
+    static EncodedJSValue customGetter(ExecState* exec, EncodedJSValue thisValue, PropertyName)
+    {
+        VM& vm = exec->vm();
+        auto scope = DECLARE_THROW_SCOPE(vm);
+
+        DOMJITNode* thisObject = jsDynamicCast<DOMJITNode*>(vm, JSValue::decode(thisValue));
+        if (!thisObject)
+            return throwVMTypeError(exec, scope);
+        return JSValue::encode(jsNumber(thisObject->value()));
+    }
+};
+
+class DOMJITGetterComplex : public DOMJITNode {
+public:
+    DOMJITGetterComplex(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
+
+    DECLARE_INFO;
+    typedef DOMJITNode Base;
+    static const unsigned StructureFlags = Base::StructureFlags;
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(JSC::JSType(LastJSCObjectType + 1), StructureFlags), info());
+    }
+
+    static DOMJITGetterComplex* create(VM& vm, JSGlobalObject* globalObject, Structure* structure)
+    {
+        DOMJITGetterComplex* getter = new (NotNull, allocateCell<DOMJITGetterComplex>(vm.heap, sizeof(DOMJITGetterComplex))) DOMJITGetterComplex(vm, structure);
+        getter->finishCreation(vm, globalObject);
+        return getter;
+    }
+
+    class DOMJITNodeDOMJIT : public DOMJIT::GetterSetter {
+    public:
+        DOMJITNodeDOMJIT()
+            : DOMJIT::GetterSetter(DOMJITGetterComplex::customGetter, nullptr, DOMJITNode::info(), SpecInt32Only)
+        {
+        }
+
+#if ENABLE(JIT)
+        Ref<DOMJIT::Patchpoint> checkDOM() override
+        {
+            return DOMJITNode::checkDOMJITNode();
+        }
+
+        static EncodedJSValue JIT_OPERATION slowCall(ExecState* exec, void* pointer)
+        {
+            VM& vm = exec->vm();
+            NativeCallFrameTracer tracer(&vm, exec);
+            auto scope = DECLARE_THROW_SCOPE(vm);
+            auto* object = static_cast<DOMJITNode*>(pointer);
+            auto* domjitGetterComplex = jsDynamicCast<DOMJITGetterComplex*>(vm, object);
+            if (domjitGetterComplex) {
+                if (domjitGetterComplex->m_enableException)
+                    return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("DOMJITGetterComplex slow call exception"))));
+            }
+            return JSValue::encode(jsNumber(object->value()));
+        }
+
+        Ref<DOMJIT::CallDOMGetterPatchpoint> callDOMGetter() override
+        {
+            RefPtr<DOMJIT::CallDOMGetterPatchpoint> patchpoint = DOMJIT::CallDOMGetterPatchpoint::create();
+            static_assert(GPRInfo::numberOfRegisters >= 4, "Number of registers should be larger or equal to 4.");
+            patchpoint->numGPScratchRegisters = GPRInfo::numberOfRegisters - 4;
+            patchpoint->numFPScratchRegisters = 3;
+            patchpoint->setGenerator([=](CCallHelpers& jit, DOMJIT::PatchpointParams& params) {
+                JSValueRegs results = params[0].jsValueRegs();
+                GPRReg domGPR = params[1].gpr();
+                for (unsigned i = 0; i < patchpoint->numGPScratchRegisters; ++i)
+                    jit.move(CCallHelpers::TrustedImm32(42), params.gpScratch(i));
+
+                params.addSlowPathCall(jit.jump(), jit, slowCall, results, domGPR);
+                return CCallHelpers::JumpList();
+
+            });
+            return *patchpoint.get();
+        }
+#endif
+    };
+
+    static DOMJIT::GetterSetter* domJITNodeGetterSetter()
+    {
+        static NeverDestroyed<DOMJITNodeDOMJIT> graph;
+        return &graph.get();
+    }
+
+private:
+    void finishCreation(VM& vm, JSGlobalObject* globalObject)
+    {
+        Base::finishCreation(vm);
+        DOMJIT::GetterSetter* domJIT = domJITNodeGetterSetter();
+        CustomGetterSetter* customGetterSetter = CustomGetterSetter::create(vm, domJIT->getter(), domJIT->setter(), domJIT);
+        putDirectCustomAccessor(vm, Identifier::fromString(&vm, "customGetter"), customGetterSetter, ReadOnly | CustomAccessor);
+        putDirectNativeFunction(vm, globalObject, Identifier::fromString(&vm, "enableException"), 0, functionEnableException, NoIntrinsic, 0);
+    }
+
+    static EncodedJSValue JSC_HOST_CALL functionEnableException(ExecState* exec)
+    {
+        VM& vm = exec->vm();
+        auto* object = jsDynamicCast<DOMJITGetterComplex*>(vm, exec->thisValue());
+        if (object)
+            object->m_enableException = true;
+        return JSValue::encode(jsUndefined());
+    }
+
+    static EncodedJSValue customGetter(ExecState* exec, EncodedJSValue thisValue, PropertyName)
+    {
+        VM& vm = exec->vm();
+        auto scope = DECLARE_THROW_SCOPE(vm);
+
+        auto* thisObject = jsDynamicCast<DOMJITNode*>(vm, JSValue::decode(thisValue));
+        if (!thisObject)
+            return throwVMTypeError(exec, scope);
+        if (auto* domjitGetterComplex = jsDynamicCast<DOMJITGetterComplex*>(vm, JSValue::decode(thisValue))) {
+            if (domjitGetterComplex->m_enableException)
+                return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("DOMJITGetterComplex slow call exception"))));
+        }
+        return JSValue::encode(jsNumber(thisObject->value()));
+    }
+
+    bool m_enableException { false };
+};
+
+class DOMJITFunctionObject : public DOMJITNode {
+public:
+    DOMJITFunctionObject(VM& vm, Structure* structure)
+        : Base(vm, structure)
+    {
+    }
+
+    DECLARE_INFO;
+    typedef DOMJITNode Base;
+    static const unsigned StructureFlags = Base::StructureFlags;
+
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(JSC::JSType(LastJSCObjectType + 1), StructureFlags), info());
+    }
+
+    static DOMJITFunctionObject* create(VM& vm, JSGlobalObject* globalObject, Structure* structure)
+    {
+        DOMJITFunctionObject* object = new (NotNull, allocateCell<DOMJITFunctionObject>(vm.heap, sizeof(DOMJITFunctionObject))) DOMJITFunctionObject(vm, structure);
+        object->finishCreation(vm, globalObject);
+        return object;
+    }
+
+    static EncodedJSValue JSC_HOST_CALL safeFunction(ExecState* exec)
+    {
+        VM& vm = exec->vm();
+        auto scope = DECLARE_THROW_SCOPE(vm);
+
+        DOMJITNode* thisObject = jsDynamicCast<DOMJITNode*>(vm, exec->thisValue());
+        if (!thisObject)
+            return throwVMTypeError(exec, scope);
+        return JSValue::encode(jsNumber(thisObject->value()));
+    }
+
+#if ENABLE(JIT)
+    static EncodedJSValue JIT_OPERATION unsafeFunction(ExecState* exec, DOMJITNode* node)
+    {
+        NativeCallFrameTracer tracer(&exec->vm(), exec);
+        return JSValue::encode(jsNumber(node->value()));
+    }
+
+    static Ref<DOMJIT::Patchpoint> checkDOMJITNode()
+    {
+        static const double value = 42.0;
+        Ref<DOMJIT::Patchpoint> patchpoint = DOMJIT::Patchpoint::create();
+        patchpoint->numFPScratchRegisters = 1;
+        patchpoint->setGenerator([=](CCallHelpers& jit, DOMJIT::PatchpointParams& params) {
+            CCallHelpers::JumpList failureCases;
+            // May use scratch registers.
+            jit.loadDouble(CCallHelpers::TrustedImmPtr(&value), params.fpScratch(0));
+            failureCases.append(jit.branch8(
+                CCallHelpers::NotEqual,
+                CCallHelpers::Address(params[0].gpr(), JSCell::typeInfoTypeOffset()),
+                CCallHelpers::TrustedImm32(JSC::JSType(LastJSCObjectType + 1))));
+            return failureCases;
+        });
+        return patchpoint;
+    }
+#endif
+
+private:
+    void finishCreation(VM&, JSGlobalObject*);
+};
+
+#if ENABLE(JIT)
+static const DOMJIT::Signature DOMJITFunctionObjectSignature((uintptr_t)DOMJITFunctionObject::unsafeFunction, DOMJITFunctionObject::checkDOMJITNode, DOMJITFunctionObject::info(), DOMJIT::Effect::forRead(DOMJIT::HeapRange::top()), SpecInt32Only);
+#endif
+
+void DOMJITFunctionObject::finishCreation(VM& vm, JSGlobalObject* globalObject)
+{
+    Base::finishCreation(vm);
+#if ENABLE(JIT)
+    putDirectNativeFunction(vm, globalObject, Identifier::fromString(&vm, "func"), 0, safeFunction, NoIntrinsic, &DOMJITFunctionObjectSignature, ReadOnly);
+#else
+    putDirectNativeFunction(vm, globalObject, Identifier::fromString(&vm, "func"), 0, safeFunction, NoIntrinsic, nullptr, ReadOnly);
+#endif
+}
+
+
+const ClassInfo Element::s_info = { "Element", &Base::s_info, nullptr, CREATE_METHOD_TABLE(Element) };
+const ClassInfo Masquerader::s_info = { "Masquerader", &Base::s_info, nullptr, CREATE_METHOD_TABLE(Masquerader) };
+const ClassInfo Root::s_info = { "Root", &Base::s_info, nullptr, CREATE_METHOD_TABLE(Root) };
+const ClassInfo ImpureGetter::s_info = { "ImpureGetter", &Base::s_info, nullptr, CREATE_METHOD_TABLE(ImpureGetter) };
+const ClassInfo CustomGetter::s_info = { "CustomGetter", &Base::s_info, nullptr, CREATE_METHOD_TABLE(CustomGetter) };
+const ClassInfo DOMJITNode::s_info = { "DOMJITNode", &Base::s_info, nullptr, CREATE_METHOD_TABLE(DOMJITNode) };
+const ClassInfo DOMJITGetter::s_info = { "DOMJITGetter", &Base::s_info, nullptr, CREATE_METHOD_TABLE(DOMJITGetter) };
+const ClassInfo DOMJITGetterComplex::s_info = { "DOMJITGetterComplex", &Base::s_info, nullptr, CREATE_METHOD_TABLE(DOMJITGetterComplex) };
+const ClassInfo DOMJITFunctionObject::s_info = { "DOMJITFunctionObject", &Base::s_info, nullptr, CREATE_METHOD_TABLE(DOMJITFunctionObject) };
+const ClassInfo RuntimeArray::s_info = { "RuntimeArray", &Base::s_info, nullptr, CREATE_METHOD_TABLE(RuntimeArray) };
+const ClassInfo SimpleObject::s_info = { "SimpleObject", &Base::s_info, nullptr, CREATE_METHOD_TABLE(SimpleObject) };
+static bool test262AsyncPassed { false };
+static bool test262AsyncTest { false };
+
+ElementHandleOwner* Element::handleOwner()
+{
+    static ElementHandleOwner* owner = 0;
+    if (!owner)
+        owner = new ElementHandleOwner();
+    return owner;
+}
+
+void Element::finishCreation(VM& vm, Root* root)
+{
+    Base::finishCreation(vm);
+    setRoot(vm, root);
+    m_root->setElement(this);
+}
+
+}
+
+static bool fillBufferWithContentsOfFile(const String& fileName, Vector<char>& buffer);
+
+class CommandLine;
+class GlobalObject;
+class Workers;
+
+template<typename Func>
+int runJSC(CommandLine, const Func&);
+static void checkException(GlobalObject*, bool isLastFile, bool hasException, JSValue, const String& uncaughtExceptionName, bool alwaysDumpUncaughtException, bool dump, bool& success);
+
+class Message : public ThreadSafeRefCounted<Message> {
+public:
+    Message(ArrayBufferContents&&, int32_t);
+    ~Message();
+    
+    ArrayBufferContents&& releaseContents() { return WTFMove(m_contents); }
+    int32_t index() const { return m_index; }
+
+private:
+    ArrayBufferContents m_contents;
+    int32_t m_index { 0 };
+};
+
+class Worker : public BasicRawSentinelNode<Worker> {
+public:
+    Worker(Workers&);
+    ~Worker();
+    
+    void enqueue(const AbstractLocker&, RefPtr<Message>);
+    RefPtr<Message> dequeue();
+    
+    static Worker& current();
+
+private:
+    static ThreadSpecific<Worker*>& currentWorker();
+
+    Workers& m_workers;
+    Deque<RefPtr<Message>> m_messages;
+};
+
+class Workers {
+public:
+    Workers();
+    ~Workers();
+    
+    template<typename Func>
+    void broadcast(const Func&);
+    
+    void report(String);
+    String tryGetReport();
+    String getReport();
+    
+    static Workers& singleton();
+    
+private:
+    friend class Worker;
+    
+    Lock m_lock;
+    Condition m_condition;
+    SentinelLinkedList<Worker, BasicRawSentinelNode<Worker>> m_workers;
+    Deque<String> m_reports;
+};
+
+static EncodedJSValue JSC_HOST_CALL functionCreateProxy(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateRuntimeArray(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateImpureGetter(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateCustomGetterObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateDOMJITNodeObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateDOMJITGetterObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateDOMJITGetterComplexObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateDOMJITFunctionObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateBuiltin(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateGlobalObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSetImpureGetterDelegate(ExecState*);
+
+static EncodedJSValue JSC_HOST_CALL functionSetElementRoot(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateRoot(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateElement(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGetElement(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCreateSimpleObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGetHiddenValue(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSetHiddenValue(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionPrintStdOut(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionPrintStdErr(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDebug(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDescribe(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDescribeArray(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSleepSeconds(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionJSCStack(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGCAndSweep(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionFullGC(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionEdenGC(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionForceGCSlowPaths(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionHeapSize(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionAddressOf(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGetGetterSetter(ExecState*);
+#ifndef NDEBUG
+static EncodedJSValue JSC_HOST_CALL functionDumpCallFrame(ExecState*);
+#endif
+static EncodedJSValue JSC_HOST_CALL functionVersion(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionRun(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionRunString(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionLoad(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionLoadString(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionReadFile(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCheckSyntax(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionReadline(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionPreciseTime(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionNeverInlineFunction(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionNoDFG(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionNoFTL(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionNoOSRExitFuzzing(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionOptimizeNextInvocation(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionNumberOfDFGCompiles(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionJSCOptions(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionReoptimizationRetryCount(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionTransferArrayBuffer(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionFailNextNewCodeBlock(ExecState*);
+static NO_RETURN_WITH_VALUE EncodedJSValue JSC_HOST_CALL functionQuit(ExecState*);
+static NO_RETURN_DUE_TO_CRASH EncodedJSValue JSC_HOST_CALL functionAbort(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionFalse1(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionFalse2(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionUndefined1(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionUndefined2(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionIsInt32(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionEffectful42(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionIdentity(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionMakeMasquerader(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionHasCustomProperties(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDumpTypesForAllVariables(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionFindTypeForExpression(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionReturnTypeFor(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDumpBasicBlockExecutionRanges(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionHasBasicBlockExecuted(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionBasicBlockExecutionCount(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionEnableExceptionFuzz(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDrainMicrotasks(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionIs32BitPlatform(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionLoadModule(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCheckModuleSyntax(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionPlatformSupportsSamplingProfiler(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGenerateHeapSnapshot(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionResetSuperSamplerState(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionEnsureArrayStorage(ExecState*);
+#if ENABLE(SAMPLING_PROFILER)
+static EncodedJSValue JSC_HOST_CALL functionStartSamplingProfiler(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSamplingProfilerStackTraces(ExecState*);
+#endif
+
+static EncodedJSValue JSC_HOST_CALL functionMaxArguments(ExecState*);
+
+#if ENABLE(WEBASSEMBLY)
+static EncodedJSValue JSC_HOST_CALL functionTestWasmModuleFunctions(ExecState*);
+#endif
+
+#if ENABLE(SAMPLING_FLAGS)
+static EncodedJSValue JSC_HOST_CALL functionSetSamplingFlags(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionClearSamplingFlags(ExecState*);
+#endif
+
+static EncodedJSValue JSC_HOST_CALL functionShadowChickenFunctionsOnStack(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSetGlobalConstRedeclarationShouldNotThrow(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGetRandomSeed(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSetRandomSeed(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionIsRope(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionCallerSourceOrigin(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGlobalObjectForObject(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarCreateRealm(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarDetachArrayBuffer(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarEvalScript(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentStart(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentReceiveBroadcast(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentReport(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentSleep(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentBroadcast(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentGetReport(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionDollarAgentLeaving(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionWaitForReport(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionHeapCapacity(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionFlashHeapAccess(ExecState*);
+
+struct Script {
+    enum class StrictMode {
+        Strict,
+        Sloppy
+    };
+
+    enum class ScriptType {
+        Script,
+        Module
+    };
+
+    enum class CodeSource {
+        File,
+        CommandLine
+    };
+
+    StrictMode strictMode;
+    CodeSource codeSource;
+    ScriptType scriptType;
+    char* argument;
+
+    Script(StrictMode strictMode, CodeSource codeSource, ScriptType scriptType, char *argument)
+        : strictMode(strictMode)
+        , codeSource(codeSource)
+        , scriptType(scriptType)
+        , argument(argument)
+    {
+        if (strictMode == StrictMode::Strict)
+            ASSERT(codeSource == CodeSource::File);
+    }
+};
+
+class CommandLine {
+public:
+    CommandLine(int argc, char** argv)
+    {
+        parseArguments(argc, argv);
+    }
+
+    bool m_interactive { false };
+    bool m_dump { false };
+    bool m_module { false };
+    bool m_exitCode { false };
+    Vector<Script> m_scripts;
+    Vector<String> m_arguments;
+    bool m_profile { false };
+    String m_profilerOutput;
+    String m_uncaughtExceptionName;
+    bool m_alwaysDumpUncaughtException { false };
+    bool m_dumpSamplingProfilerData { false };
+    bool m_enableRemoteDebugging { false };
+
+    void parseArguments(int, char**);
+};
+
+static const char interactivePrompt[] = ">>> ";
+
+class StopWatch {
+public:
+    void start();
+    void stop();
+    long getElapsedMS(); // call stop() first
+
+private:
+    double m_startTime;
+    double m_stopTime;
+};
+
+void StopWatch::start()
+{
+    m_startTime = monotonicallyIncreasingTime();
+}
+
+void StopWatch::stop()
+{
+    m_stopTime = monotonicallyIncreasingTime();
+}
+
+long StopWatch::getElapsedMS()
+{
+    return static_cast<long>((m_stopTime - m_startTime) * 1000);
+}
+
+template<typename Vector>
+static inline String stringFromUTF(const Vector& utf8)
+{
+    return String::fromUTF8WithLatin1Fallback(utf8.data(), utf8.size());
+}
+
+template<typename Vector>
+static inline SourceCode jscSource(const Vector& utf8, const SourceOrigin& sourceOrigin, const String& filename)
+{
+    String str = stringFromUTF(utf8);
+    return makeSource(str, sourceOrigin, filename);
+}
+
+class GlobalObject : public JSGlobalObject {
+private:
+    GlobalObject(VM&, Structure*);
+
+public:
+    typedef JSGlobalObject Base;
+
+    static GlobalObject* create(VM& vm, Structure* structure, const Vector<String>& arguments)
+    {
+        GlobalObject* object = new (NotNull, allocateCell<GlobalObject>(vm.heap)) GlobalObject(vm, structure);
+        object->finishCreation(vm, arguments);
+        return object;
+    }
+
+    static const bool needsDestruction = false;
+
+    DECLARE_INFO;
+    static const GlobalObjectMethodTable s_globalObjectMethodTable;
+
+    static Structure* createStructure(VM& vm, JSValue prototype)
+    {
+        return Structure::create(vm, 0, prototype, TypeInfo(GlobalObjectType, StructureFlags), info());
+    }
+
+    static RuntimeFlags javaScriptRuntimeFlags(const JSGlobalObject*) { return RuntimeFlags::createAllEnabled(); }
+
+protected:
+    void finishCreation(VM& vm, const Vector<String>& arguments)
+    {
+        Base::finishCreation(vm);
+        
+        addFunction(vm, "debug", functionDebug, 1);
+        addFunction(vm, "describe", functionDescribe, 1);
+        addFunction(vm, "describeArray", functionDescribeArray, 1);
+        addFunction(vm, "print", functionPrintStdOut, 1);
+        addFunction(vm, "printErr", functionPrintStdErr, 1);
+        addFunction(vm, "quit", functionQuit, 0);
+        addFunction(vm, "abort", functionAbort, 0);
+        addFunction(vm, "gc", functionGCAndSweep, 0);
+        addFunction(vm, "fullGC", functionFullGC, 0);
+        addFunction(vm, "edenGC", functionEdenGC, 0);
+        addFunction(vm, "forceGCSlowPaths", functionForceGCSlowPaths, 0);
+        addFunction(vm, "gcHeapSize", functionHeapSize, 0);
+        addFunction(vm, "addressOf", functionAddressOf, 1);
+        addFunction(vm, "getGetterSetter", functionGetGetterSetter, 2);
+#ifndef NDEBUG
+        addFunction(vm, "dumpCallFrame", functionDumpCallFrame, 0);
+#endif
+        addFunction(vm, "version", functionVersion, 1);
+        addFunction(vm, "run", functionRun, 1);
+        addFunction(vm, "runString", functionRunString, 1);
+        addFunction(vm, "load", functionLoad, 1);
+        addFunction(vm, "loadString", functionLoadString, 1);
+        addFunction(vm, "readFile", functionReadFile, 2);
+        addFunction(vm, "read", functionReadFile, 2);
+        addFunction(vm, "checkSyntax", functionCheckSyntax, 1);
+        addFunction(vm, "sleepSeconds", functionSleepSeconds, 1);
+        addFunction(vm, "jscStack", functionJSCStack, 1);
+        addFunction(vm, "readline", functionReadline, 0);
+        addFunction(vm, "preciseTime", functionPreciseTime, 0);
+        addFunction(vm, "neverInlineFunction", functionNeverInlineFunction, 1);
+        addFunction(vm, "noInline", functionNeverInlineFunction, 1);
+        addFunction(vm, "noDFG", functionNoDFG, 1);
+        addFunction(vm, "noFTL", functionNoFTL, 1);
+        addFunction(vm, "noOSRExitFuzzing", functionNoOSRExitFuzzing, 1);
+        addFunction(vm, "numberOfDFGCompiles", functionNumberOfDFGCompiles, 1);
+        addFunction(vm, "jscOptions", functionJSCOptions, 0);
+        addFunction(vm, "optimizeNextInvocation", functionOptimizeNextInvocation, 1);
+        addFunction(vm, "reoptimizationRetryCount", functionReoptimizationRetryCount, 1);
+        addFunction(vm, "transferArrayBuffer", functionTransferArrayBuffer, 1);
+        addFunction(vm, "failNextNewCodeBlock", functionFailNextNewCodeBlock, 1);
+#if ENABLE(SAMPLING_FLAGS)
+        addFunction(vm, "setSamplingFlags", functionSetSamplingFlags, 1);
+        addFunction(vm, "clearSamplingFlags", functionClearSamplingFlags, 1);
+#endif
+        addFunction(vm, "shadowChickenFunctionsOnStack", functionShadowChickenFunctionsOnStack, 0);
+        addFunction(vm, "setGlobalConstRedeclarationShouldNotThrow", functionSetGlobalConstRedeclarationShouldNotThrow, 0);
+        addConstructableFunction(vm, "Root", functionCreateRoot, 0);
+        addConstructableFunction(vm, "Element", functionCreateElement, 1);
+        addFunction(vm, "getElement", functionGetElement, 1);
+        addFunction(vm, "setElementRoot", functionSetElementRoot, 2);
+        
+        addConstructableFunction(vm, "SimpleObject", functionCreateSimpleObject, 0);
+        addFunction(vm, "getHiddenValue", functionGetHiddenValue, 1);
+        addFunction(vm, "setHiddenValue", functionSetHiddenValue, 2);
+        
+        putDirectNativeFunction(vm, this, Identifier::fromString(&vm, "DFGTrue"), 0, functionFalse1, DFGTrueIntrinsic, DontEnum);
+        putDirectNativeFunction(vm, this, Identifier::fromString(&vm, "OSRExit"), 0, functionUndefined1, OSRExitIntrinsic, DontEnum);
+        putDirectNativeFunction(vm, this, Identifier::fromString(&vm, "isFinalTier"), 0, functionFalse2, IsFinalTierIntrinsic, DontEnum);
+        putDirectNativeFunction(vm, this, Identifier::fromString(&vm, "predictInt32"), 0, functionUndefined2, SetInt32HeapPredictionIntrinsic, DontEnum);
+        putDirectNativeFunction(vm, this, Identifier::fromString(&vm, "isInt32"), 0, functionIsInt32, CheckInt32Intrinsic, DontEnum);
+        putDirectNativeFunction(vm, this, Identifier::fromString(&vm, "fiatInt52"), 0, functionIdentity, FiatInt52Intrinsic, DontEnum);
+        
+        addFunction(vm, "effectful42", functionEffectful42, 0);
+        addFunction(vm, "makeMasquerader", functionMakeMasquerader, 0);
+        addFunction(vm, "hasCustomProperties", functionHasCustomProperties, 0);
+
+        addFunction(vm, "createProxy", functionCreateProxy, 1);
+        addFunction(vm, "createRuntimeArray", functionCreateRuntimeArray, 0);
+
+        addFunction(vm, "createImpureGetter", functionCreateImpureGetter, 1);
+        addFunction(vm, "createCustomGetterObject", functionCreateCustomGetterObject, 0);
+        addFunction(vm, "createDOMJITNodeObject", functionCreateDOMJITNodeObject, 0);
+        addFunction(vm, "createDOMJITGetterObject", functionCreateDOMJITGetterObject, 0);
+        addFunction(vm, "createDOMJITGetterComplexObject", functionCreateDOMJITGetterComplexObject, 0);
+        addFunction(vm, "createDOMJITFunctionObject", functionCreateDOMJITFunctionObject, 0);
+        addFunction(vm, "createBuiltin", functionCreateBuiltin, 2);
+        addFunction(vm, "createGlobalObject", functionCreateGlobalObject, 0);
+        addFunction(vm, "setImpureGetterDelegate", functionSetImpureGetterDelegate, 2);
+
+        addFunction(vm, "dumpTypesForAllVariables", functionDumpTypesForAllVariables , 0);
+        addFunction(vm, "findTypeForExpression", functionFindTypeForExpression, 2);
+        addFunction(vm, "returnTypeFor", functionReturnTypeFor, 1);
+
+        addFunction(vm, "dumpBasicBlockExecutionRanges", functionDumpBasicBlockExecutionRanges , 0);
+        addFunction(vm, "hasBasicBlockExecuted", functionHasBasicBlockExecuted, 2);
+        addFunction(vm, "basicBlockExecutionCount", functionBasicBlockExecutionCount, 2);
+
+        addFunction(vm, "enableExceptionFuzz", functionEnableExceptionFuzz, 0);
+
+        addFunction(vm, "drainMicrotasks", functionDrainMicrotasks, 0);
+
+        addFunction(vm, "getRandomSeed", functionGetRandomSeed, 0);
+        addFunction(vm, "setRandomSeed", functionSetRandomSeed, 1);
+        addFunction(vm, "isRope", functionIsRope, 1);
+        addFunction(vm, "callerSourceOrigin", functionCallerSourceOrigin, 0);
+
+        addFunction(vm, "globalObjectForObject", functionGlobalObjectForObject, 1);
+
+        addFunction(vm, "is32BitPlatform", functionIs32BitPlatform, 0);
+
+        addFunction(vm, "loadModule", functionLoadModule, 1);
+        addFunction(vm, "checkModuleSyntax", functionCheckModuleSyntax, 1);
+
+        addFunction(vm, "platformSupportsSamplingProfiler", functionPlatformSupportsSamplingProfiler, 0);
+        addFunction(vm, "generateHeapSnapshot", functionGenerateHeapSnapshot, 0);
+        addFunction(vm, "resetSuperSamplerState", functionResetSuperSamplerState, 0);
+        addFunction(vm, "ensureArrayStorage", functionEnsureArrayStorage, 0);
+#if ENABLE(SAMPLING_PROFILER)
+        addFunction(vm, "startSamplingProfiler", functionStartSamplingProfiler, 0);
+        addFunction(vm, "samplingProfilerStackTraces", functionSamplingProfilerStackTraces, 0);
+#endif
+
+        addFunction(vm, "maxArguments", functionMaxArguments, 0);
+
+#if ENABLE(WEBASSEMBLY)
+        addFunction(vm, "testWasmModuleFunctions", functionTestWasmModuleFunctions, 0);
+#endif
+
+        if (!arguments.isEmpty()) {
+            JSArray* array = constructEmptyArray(globalExec(), 0);
+            for (size_t i = 0; i < arguments.size(); ++i)
+                array->putDirectIndex(globalExec(), i, jsString(globalExec(), arguments[i]));
+            putDirect(vm, Identifier::fromString(globalExec(), "arguments"), array);
+        }
+
+        putDirect(vm, Identifier::fromString(globalExec(), "console"), jsUndefined());
+        
+        Structure* plainObjectStructure = JSFinalObject::createStructure(vm, this, objectPrototype(), 0);
+        
+        JSObject* dollar = JSFinalObject::create(vm, plainObjectStructure);
+        putDirect(vm, Identifier::fromString(globalExec(), "$"), dollar);
+        
+        addFunction(vm, dollar, "createRealm", functionDollarCreateRealm, 0);
+        addFunction(vm, dollar, "detachArrayBuffer", functionDollarDetachArrayBuffer, 1);
+        addFunction(vm, dollar, "evalScript", functionDollarEvalScript, 1);
+        
+        dollar->putDirect(vm, Identifier::fromString(globalExec(), "global"), this);
+        
+        JSObject* agent = JSFinalObject::create(vm, plainObjectStructure);
+        dollar->putDirect(vm, Identifier::fromString(globalExec(), "agent"), agent);
+        
+        // The test262 INTERPRETING.md document says that some of these functions are just in the main
+        // thread and some are in the other threads. We just put them in all threads.
+        addFunction(vm, agent, "start", functionDollarAgentStart, 1);
+        addFunction(vm, agent, "receiveBroadcast", functionDollarAgentReceiveBroadcast, 1);
+        addFunction(vm, agent, "report", functionDollarAgentReport, 1);
+        addFunction(vm, agent, "sleep", functionDollarAgentSleep, 1);
+        addFunction(vm, agent, "broadcast", functionDollarAgentBroadcast, 1);
+        addFunction(vm, agent, "getReport", functionDollarAgentGetReport, 0);
+        addFunction(vm, agent, "leaving", functionDollarAgentLeaving, 0);
+        
+        addFunction(vm, "waitForReport", functionWaitForReport, 0);
+
+        addFunction(vm, "heapCapacity", functionHeapCapacity, 0);
+        addFunction(vm, "flashHeapAccess", functionFlashHeapAccess, 0);
+    }
+    
+    void addFunction(VM& vm, JSObject* object, const char* name, NativeFunction function, unsigned arguments)
+    {
+        Identifier identifier = Identifier::fromString(&vm, name);
+        object->putDirect(vm, identifier, JSFunction::create(vm, this, arguments, identifier.string(), function));
+    }
+
+    void addFunction(VM& vm, const char* name, NativeFunction function, unsigned arguments)
+    {
+        addFunction(vm, this, name, function, arguments);
+    }
+    
+    void addConstructableFunction(VM& vm, const char* name, NativeFunction function, unsigned arguments)
+    {
+        Identifier identifier = Identifier::fromString(&vm, name);
+        putDirect(vm, identifier, JSFunction::create(vm, this, arguments, identifier.string(), function, NoIntrinsic, function));
+    }
+
+    static JSInternalPromise* moduleLoaderImportModule(JSGlobalObject*, ExecState*, JSModuleLoader*, JSString*, const SourceOrigin&);
+    static JSInternalPromise* moduleLoaderResolve(JSGlobalObject*, ExecState*, JSModuleLoader*, JSValue, JSValue, JSValue);
+    static JSInternalPromise* moduleLoaderFetch(JSGlobalObject*, ExecState*, JSModuleLoader*, JSValue, JSValue);
+};
+
+const ClassInfo GlobalObject::s_info = { "global", &JSGlobalObject::s_info, nullptr, CREATE_METHOD_TABLE(GlobalObject) };
+const GlobalObjectMethodTable GlobalObject::s_globalObjectMethodTable = {
+    &supportsRichSourceInfo,
+    &shouldInterruptScript,
+    &javaScriptRuntimeFlags,
+    nullptr,
+    &shouldInterruptScriptBeforeTimeout,
+    &moduleLoaderImportModule,
+    &moduleLoaderResolve,
+    &moduleLoaderFetch,
+    nullptr,
+    nullptr,
+    nullptr
+};
+
+GlobalObject::GlobalObject(VM& vm, Structure* structure)
+    : JSGlobalObject(vm, structure, &s_globalObjectMethodTable)
+{
+}
+
+static UChar pathSeparator()
+{
+#if OS(WINDOWS)
+    return '\\';
+#else
+    return '/';
+#endif
+}
+
+struct DirectoryName {
+    // In unix, it is "/". In Windows, it becomes a drive letter like "C:\"
+    String rootName;
+
+    // If the directory name is "/home/WebKit", this becomes "home/WebKit". If the directory name is "/", this becomes "".
+    String queryName;
+};
+
+struct ModuleName {
+    ModuleName(const String& moduleName);
+
+    bool startsWithRoot() const
+    {
+        return !queries.isEmpty() && queries[0].isEmpty();
+    }
+
+    Vector<String> queries;
+};
+
+ModuleName::ModuleName(const String& moduleName)
+{
+    // A module name given from code is represented as the UNIX style path. Like, `./A/B.js`.
+    moduleName.split('/', true, queries);
+}
+
+static std::optional<DirectoryName> extractDirectoryName(const String& absolutePathToFile)
+{
+    size_t firstSeparatorPosition = absolutePathToFile.find(pathSeparator());
+    if (firstSeparatorPosition == notFound)
+        return std::nullopt;
+    DirectoryName directoryName;
+    directoryName.rootName = absolutePathToFile.substring(0, firstSeparatorPosition + 1); // Include the separator.
+    size_t lastSeparatorPosition = absolutePathToFile.reverseFind(pathSeparator());
+    ASSERT_WITH_MESSAGE(lastSeparatorPosition != notFound, "If the separator is not found, this function already returns when performing the forward search.");
+    if (firstSeparatorPosition == lastSeparatorPosition)
+        directoryName.queryName = StringImpl::empty();
+    else {
+        size_t queryStartPosition = firstSeparatorPosition + 1;
+        size_t queryLength = lastSeparatorPosition - queryStartPosition; // Not include the last separator.
+        directoryName.queryName = absolutePathToFile.substring(queryStartPosition, queryLength);
+    }
+    return directoryName;
+}
+
+static std::optional<DirectoryName> currentWorkingDirectory()
+{
+#if OS(WINDOWS)
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/aa364934.aspx
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247.aspx#maxpath
+    // The _MAX_PATH in Windows is 260. If the path of the current working directory is longer than that, _getcwd truncates the result.
+    // And other I/O functions taking a path name also truncate it. To avoid this situation,
+    //
+    // (1). When opening the file in Windows for modules, we always use the abosolute path and add "\\?\" prefix to the path name.
+    // (2). When retrieving the current working directory, use GetCurrentDirectory instead of _getcwd.
+    //
+    // In the path utility functions inside the JSC shell, we does not handle the UNC and UNCW including the network host name.
+    DWORD bufferLength = ::GetCurrentDirectoryW(0, nullptr);
+    if (!bufferLength)
+        return std::nullopt;
+    // In Windows, wchar_t is the UTF-16LE.
+    // https://msdn.microsoft.com/en-us/library/dd374081.aspx
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/ff381407.aspx
+    auto buffer = std::make_unique<wchar_t[]>(bufferLength);
+    DWORD lengthNotIncludingNull = ::GetCurrentDirectoryW(bufferLength, buffer.get());
+    static_assert(sizeof(wchar_t) == sizeof(UChar), "In Windows, both are UTF-16LE");
+    String directoryString = String(reinterpret_cast<UChar*>(buffer.get()));
+    // We don't support network path like \\host\share\<path name>.
+    if (directoryString.startsWith("\\\\"))
+        return std::nullopt;
+#else
+    auto buffer = std::make_unique<char[]>(PATH_MAX);
+    if (!getcwd(buffer.get(), PATH_MAX))
+        return std::nullopt;
+    String directoryString = String::fromUTF8(buffer.get());
+#endif
+    if (directoryString.isEmpty())
+        return std::nullopt;
+
+    if (directoryString[directoryString.length() - 1] == pathSeparator())
+        return extractDirectoryName(directoryString);
+    // Append the seperator to represents the file name. extractDirectoryName only accepts the absolute file name.
+    return extractDirectoryName(makeString(directoryString, pathSeparator()));
+}
+
+static String resolvePath(const DirectoryName& directoryName, const ModuleName& moduleName)
+{
+    Vector<String> directoryPieces;
+    directoryName.queryName.split(pathSeparator(), false, directoryPieces);
+
+    // Only first '/' is recognized as the path from the root.
+    if (moduleName.startsWithRoot())
+        directoryPieces.clear();
+
+    for (const auto& query : moduleName.queries) {
+        if (query == String(ASCIILiteral(".."))) {
+            if (!directoryPieces.isEmpty())
+                directoryPieces.removeLast();
+        } else if (!query.isEmpty() && query != String(ASCIILiteral(".")))
+            directoryPieces.append(query);
+    }
+
+    StringBuilder builder;
+    builder.append(directoryName.rootName);
+    for (size_t i = 0; i < directoryPieces.size(); ++i) {
+        builder.append(directoryPieces[i]);
+        if (i + 1 != directoryPieces.size())
+            builder.append(pathSeparator());
+    }
+    return builder.toString();
+}
+
+static String absolutePath(const String& fileName)
+{
+    auto directoryName = currentWorkingDirectory();
+    if (!directoryName)
+        return fileName;
+    return resolvePath(directoryName.value(), ModuleName(fileName.impl()));
+}
+
+JSInternalPromise* GlobalObject::moduleLoaderImportModule(JSGlobalObject* globalObject, ExecState* exec, JSModuleLoader*, JSString* moduleNameValue, const SourceOrigin& sourceOrigin)
+{
+    VM& vm = globalObject->vm();
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+
+    auto rejectPromise = [&] (JSValue error) {
+        return JSInternalPromiseDeferred::create(exec, globalObject)->reject(exec, error);
+    };
+
+    if (sourceOrigin.isNull())
+        return rejectPromise(createError(exec, ASCIILiteral("Could not resolve the module specifier.")));
+
+    auto referrer = sourceOrigin.string();
+    auto moduleName = moduleNameValue->value(exec);
+    if (UNLIKELY(scope.exception())) {
+        JSValue exception = scope.exception();
+        scope.clearException();
+        return rejectPromise(exception);
+    }
+
+    auto directoryName = extractDirectoryName(referrer.impl());
+    if (!directoryName)
+        return rejectPromise(createError(exec, makeString("Could not resolve the referrer name '", String(referrer.impl()), "'.")));
+
+    return JSC::importModule(exec, Identifier::fromString(&vm, resolvePath(directoryName.value(), ModuleName(moduleName))), jsUndefined());
+}
+
+JSInternalPromise* GlobalObject::moduleLoaderResolve(JSGlobalObject* globalObject, ExecState* exec, JSModuleLoader*, JSValue keyValue, JSValue referrerValue, JSValue)
+{
+    VM& vm = globalObject->vm();
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+
+    JSInternalPromiseDeferred* deferred = JSInternalPromiseDeferred::create(exec, globalObject);
+    const Identifier key = keyValue.toPropertyKey(exec);
+    if (UNLIKELY(scope.exception())) {
+        JSValue exception = scope.exception();
+        scope.clearException();
+        return deferred->reject(exec, exception);
+    }
+
+    if (key.isSymbol())
+        return deferred->resolve(exec, keyValue);
+
+    if (referrerValue.isUndefined()) {
+        auto directoryName = currentWorkingDirectory();
+        if (!directoryName)
+            return deferred->reject(exec, createError(exec, ASCIILiteral("Could not resolve the current working directory.")));
+        return deferred->resolve(exec, jsString(exec, resolvePath(directoryName.value(), ModuleName(key.impl()))));
+    }
+
+    const Identifier referrer = referrerValue.toPropertyKey(exec);
+    if (UNLIKELY(scope.exception())) {
+        JSValue exception = scope.exception();
+        scope.clearException();
+        return deferred->reject(exec, exception);
+    }
+
+    if (referrer.isSymbol()) {
+        auto directoryName = currentWorkingDirectory();
+        if (!directoryName)
+            return deferred->reject(exec, createError(exec, ASCIILiteral("Could not resolve the current working directory.")));
+        return deferred->resolve(exec, jsString(exec, resolvePath(directoryName.value(), ModuleName(key.impl()))));
+    }
+
+    // If the referrer exists, we assume that the referrer is the correct absolute path.
+    auto directoryName = extractDirectoryName(referrer.impl());
+    if (!directoryName)
+        return deferred->reject(exec, createError(exec, makeString("Could not resolve the referrer name '", String(referrer.impl()), "'.")));
+    return deferred->resolve(exec, jsString(exec, resolvePath(directoryName.value(), ModuleName(key.impl()))));
+}
+
+static void convertShebangToJSComment(Vector<char>& buffer)
+{
+    if (buffer.size() >= 2) {
+        if (buffer[0] == '#' && buffer[1] == '!')
+            buffer[0] = buffer[1] = '/';
+    }
+}
+
+static bool fillBufferWithContentsOfFile(FILE* file, Vector<char>& buffer)
+{
+    // We might have injected "use strict"; at the top.
+    size_t initialSize = buffer.size();
+    fseek(file, 0, SEEK_END);
+    size_t bufferCapacity = ftell(file);
+    fseek(file, 0, SEEK_SET);
+    buffer.resize(bufferCapacity + initialSize);
+    size_t readSize = fread(buffer.data() + initialSize, 1, buffer.size(), file);
+    return readSize == buffer.size() - initialSize;
+}
+
+static bool fillBufferWithContentsOfFile(const String& fileName, Vector<char>& buffer)
+{
+    FILE* f = fopen(fileName.utf8().data(), "rb");
+    if (!f) {
+        fprintf(stderr, "Could not open file: %s\n", fileName.utf8().data());
+        return false;
+    }
+
+    bool result = fillBufferWithContentsOfFile(f, buffer);
+    fclose(f);
+
+    return result;
+}
+
+static bool fetchScriptFromLocalFileSystem(const String& fileName, Vector<char>& buffer)
+{
+    if (!fillBufferWithContentsOfFile(fileName, buffer))
+        return false;
+    convertShebangToJSComment(buffer);
+    return true;
+}
+
+static bool fetchModuleFromLocalFileSystem(const String& fileName, Vector<char>& buffer)
+{
+    // We assume that fileName is always an absolute path.
+#if OS(WINDOWS)
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247.aspx#maxpath
+    // Use long UNC to pass the long path name to the Windows APIs.
+    String longUNCPathName = WTF::makeString("\\\\?\\", fileName);
+    static_assert(sizeof(wchar_t) == sizeof(UChar), "In Windows, both are UTF-16LE");
+    auto utf16Vector = longUNCPathName.charactersWithNullTermination();
+    FILE* f = _wfopen(reinterpret_cast<wchar_t*>(utf16Vector.data()), L"rb");
+#else
+    FILE* f = fopen(fileName.utf8().data(), "r");
+#endif
+    if (!f) {
+        fprintf(stderr, "Could not open file: %s\n", fileName.utf8().data());
+        return false;
+    }
+
+    bool result = fillBufferWithContentsOfFile(f, buffer);
+    if (result)
+        convertShebangToJSComment(buffer);
+    fclose(f);
+
+    return result;
+}
+
+JSInternalPromise* GlobalObject::moduleLoaderFetch(JSGlobalObject* globalObject, ExecState* exec, JSModuleLoader*, JSValue key, JSValue)
+{
+    VM& vm = globalObject->vm();
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+    JSInternalPromiseDeferred* deferred = JSInternalPromiseDeferred::create(exec, globalObject);
+    String moduleKey = key.toWTFString(exec);
+    if (UNLIKELY(scope.exception())) {
+        JSValue exception = scope.exception();
+        scope.clearException();
+        return deferred->reject(exec, exception);
+    }
+
+    // Here, now we consider moduleKey as the fileName.
+    Vector<char> utf8;
+    if (!fetchModuleFromLocalFileSystem(moduleKey, utf8))
+        return deferred->reject(exec, createError(exec, makeString("Could not open file '", moduleKey, "'.")));
+
+    return deferred->resolve(exec, JSSourceCode::create(exec->vm(), makeSource(stringFromUTF(utf8), SourceOrigin { moduleKey }, moduleKey, TextPosition(), SourceProviderSourceType::Module)));
+}
+
+
+static EncodedJSValue printInternal(ExecState* exec, FILE* out)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (test262AsyncTest) {
+        JSValue value = exec->argument(0);
+        if (value.isString() && WTF::equal(asString(value)->value(exec).impl(), "Test262:AsyncTestComplete"))
+            test262AsyncPassed = true;
+        return JSValue::encode(jsUndefined());
+    }
+
+    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
+        if (i)
+            if (EOF == fputc(' ', out))
+                goto fail;
+
+        auto viewWithString = exec->uncheckedArgument(i).toString(exec)->viewWithUnderlyingString(*exec);
+        RETURN_IF_EXCEPTION(scope, encodedJSValue());
+        if (fprintf(out, "%s", viewWithString.view.utf8().data()) < 0)
+            goto fail;
+    }
+
+    fputc('\n', out);
+fail:
+    fflush(out);
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionPrintStdOut(ExecState* exec) { return printInternal(exec, stdout); }
+EncodedJSValue JSC_HOST_CALL functionPrintStdErr(ExecState* exec) { return printInternal(exec, stderr); }
+
+#ifndef NDEBUG
+EncodedJSValue JSC_HOST_CALL functionDumpCallFrame(ExecState* exec)
+{
+    VMEntryFrame* topVMEntryFrame = exec->vm().topVMEntryFrame;
+    ExecState* callerFrame = exec->callerFrame(topVMEntryFrame);
+    if (callerFrame)
+        exec->vm().interpreter->dumpCallFrame(callerFrame);
+    return JSValue::encode(jsUndefined());
+}
+#endif
+
+EncodedJSValue JSC_HOST_CALL functionDebug(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+    auto viewWithString = exec->argument(0).toString(exec)->viewWithUnderlyingString(*exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    fprintf(stderr, "--> %s\n", viewWithString.view.utf8().data());
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionDescribe(ExecState* exec)
+{
+    if (exec->argumentCount() < 1)
+        return JSValue::encode(jsUndefined());
+    return JSValue::encode(jsString(exec, toString(exec->argument(0))));
+}
+
+EncodedJSValue JSC_HOST_CALL functionDescribeArray(ExecState* exec)
+{
+    if (exec->argumentCount() < 1)
+        return JSValue::encode(jsUndefined());
+    VM& vm = exec->vm();
+    JSObject* object = jsDynamicCast<JSObject*>(vm, exec->argument(0));
+    if (!object)
+        return JSValue::encode(jsNontrivialString(exec, ASCIILiteral("<not object>")));
+    return JSValue::encode(jsNontrivialString(exec, toString("<Butterfly: ", RawPointer(object->butterfly()), "; public length: ", object->getArrayLength(), "; vector length: ", object->getVectorLength(), ">")));
+}
+
+EncodedJSValue JSC_HOST_CALL functionSleepSeconds(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (exec->argumentCount() >= 1) {
+        Seconds seconds = Seconds(exec->argument(0).toNumber(exec));
+        RETURN_IF_EXCEPTION(scope, encodedJSValue());
+        sleep(seconds);
+    }
+    
+    return JSValue::encode(jsUndefined());
+}
+
+class FunctionJSCStackFunctor {
+public:
+    FunctionJSCStackFunctor(StringBuilder& trace)
+        : m_trace(trace)
+    {
+    }
+
+    StackVisitor::Status operator()(StackVisitor& visitor) const
+    {
+        m_trace.append(String::format("    %zu   %s\n", visitor->index(), visitor->toString().utf8().data()));
+        return StackVisitor::Continue;
+    }
+
+private:
+    StringBuilder& m_trace;
+};
+
+EncodedJSValue JSC_HOST_CALL functionJSCStack(ExecState* exec)
+{
+    StringBuilder trace;
+    trace.appendLiteral("--> Stack trace:\n");
+
+    FunctionJSCStackFunctor functor(trace);
+    exec->iterate(functor);
+    fprintf(stderr, "%s", trace.toString().utf8().data());
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateRoot(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    return JSValue::encode(Root::create(exec->vm(), exec->lexicalGlobalObject()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateElement(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    JSLockHolder lock(vm);
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    Root* root = jsDynamicCast<Root*>(vm, exec->argument(0));
+    if (!root)
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Cannot create Element without a Root."))));
+    return JSValue::encode(Element::create(vm, exec->lexicalGlobalObject(), root));
+}
+
+EncodedJSValue JSC_HOST_CALL functionGetElement(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    VM& vm = exec->vm();
+    Root* root = jsDynamicCast<Root*>(vm, exec->argument(0));
+    if (!root)
+        return JSValue::encode(jsUndefined());
+    Element* result = root->element();
+    return JSValue::encode(result ? result : jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionSetElementRoot(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    VM& vm = exec->vm();
+    Element* element = jsDynamicCast<Element*>(vm, exec->argument(0));
+    Root* root = jsDynamicCast<Root*>(vm, exec->argument(1));
+    if (element && root)
+        element->setRoot(exec->vm(), root);
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateSimpleObject(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    return JSValue::encode(SimpleObject::create(exec->vm(), exec->lexicalGlobalObject()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionGetHiddenValue(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    JSLockHolder lock(vm);
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    SimpleObject* simpleObject = jsDynamicCast<SimpleObject*>(vm, exec->argument(0));
+    if (UNLIKELY(!simpleObject)) {
+        throwTypeError(exec, scope, ASCIILiteral("Invalid use of getHiddenValue test function"));
+        return encodedJSValue();
+    }
+    return JSValue::encode(simpleObject->hiddenValue());
+}
+
+EncodedJSValue JSC_HOST_CALL functionSetHiddenValue(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    JSLockHolder lock(vm);
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    SimpleObject* simpleObject = jsDynamicCast<SimpleObject*>(vm, exec->argument(0));
+    if (UNLIKELY(!simpleObject)) {
+        throwTypeError(exec, scope, ASCIILiteral("Invalid use of setHiddenValue test function"));
+        return encodedJSValue();
+    }
+    JSValue value = exec->argument(1);
+    simpleObject->setHiddenValue(exec->vm(), value);
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateProxy(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    JSValue target = exec->argument(0);
+    if (!target.isObject())
+        return JSValue::encode(jsUndefined());
+    JSObject* jsTarget = asObject(target.asCell());
+    Structure* structure = JSProxy::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsTarget->getPrototypeDirect(), ImpureProxyType);
+    JSProxy* proxy = JSProxy::create(exec->vm(), structure, jsTarget);
+    return JSValue::encode(proxy);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateRuntimeArray(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    RuntimeArray* array = RuntimeArray::create(exec);
+    return JSValue::encode(array);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateImpureGetter(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    JSValue target = exec->argument(0);
+    JSObject* delegate = nullptr;
+    if (target.isObject())
+        delegate = asObject(target.asCell());
+    Structure* structure = ImpureGetter::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsNull());
+    ImpureGetter* result = ImpureGetter::create(exec->vm(), structure, delegate);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateCustomGetterObject(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    Structure* structure = CustomGetter::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsNull());
+    CustomGetter* result = CustomGetter::create(exec->vm(), structure);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateDOMJITNodeObject(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    Structure* structure = DOMJITNode::createStructure(exec->vm(), exec->lexicalGlobalObject(), DOMJITGetter::create(exec->vm(), DOMJITGetter::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsNull())));
+    DOMJITNode* result = DOMJITNode::create(exec->vm(), structure);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateDOMJITGetterObject(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    Structure* structure = DOMJITGetter::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsNull());
+    DOMJITGetter* result = DOMJITGetter::create(exec->vm(), structure);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateDOMJITGetterComplexObject(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    Structure* structure = DOMJITGetterComplex::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsNull());
+    DOMJITGetterComplex* result = DOMJITGetterComplex::create(exec->vm(), exec->lexicalGlobalObject(), structure);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCreateDOMJITFunctionObject(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    Structure* structure = DOMJITFunctionObject::createStructure(exec->vm(), exec->lexicalGlobalObject(), jsNull());
+    DOMJITFunctionObject* result = DOMJITFunctionObject::create(exec->vm(), exec->lexicalGlobalObject(), structure);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionSetImpureGetterDelegate(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    JSLockHolder lock(vm);
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    JSValue base = exec->argument(0);
+    if (!base.isObject())
+        return JSValue::encode(jsUndefined());
+    JSValue delegate = exec->argument(1);
+    if (!delegate.isObject())
+        return JSValue::encode(jsUndefined());
+    ImpureGetter* impureGetter = jsDynamicCast<ImpureGetter*>(vm, asObject(base.asCell()));
+    if (UNLIKELY(!impureGetter)) {
+        throwTypeError(exec, scope, ASCIILiteral("argument is not an ImpureGetter"));
+        return encodedJSValue();
+    }
+    impureGetter->setDelegate(vm, asObject(delegate.asCell()));
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionGCAndSweep(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    exec->heap()->collectAllGarbage();
+    return JSValue::encode(jsNumber(exec->heap()->sizeAfterLastFullCollection()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionFullGC(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    exec->heap()->collectSync(CollectionScope::Full);
+    return JSValue::encode(jsNumber(exec->heap()->sizeAfterLastFullCollection()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionEdenGC(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    exec->heap()->collectSync(CollectionScope::Eden);
+    return JSValue::encode(jsNumber(exec->heap()->sizeAfterLastEdenCollection()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionForceGCSlowPaths(ExecState*)
+{
+    // It's best for this to be the first thing called in the 
+    // JS program so the option is set to true before we JIT.
+    Options::forceGCSlowPaths() = true;
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionHeapSize(ExecState* exec)
+{
+    JSLockHolder lock(exec);
+    return JSValue::encode(jsNumber(exec->heap()->size()));
+}
+
+// This function is not generally very helpful in 64-bit code as the tag and payload
+// share a register. But in 32-bit JITed code the tag may not be checked if an
+// optimization removes type checking requirements, such as in ===.
+EncodedJSValue JSC_HOST_CALL functionAddressOf(ExecState* exec)
+{
+    JSValue value = exec->argument(0);
+    if (!value.isCell())
+        return JSValue::encode(jsUndefined());
+    // Need to cast to uint64_t so bitwise_cast will play along.
+    uint64_t asNumber = reinterpret_cast<uint64_t>(value.asCell());
+    EncodedJSValue returnValue = JSValue::encode(jsNumber(bitwise_cast<double>(asNumber)));
+    return returnValue;
+}
+
+static EncodedJSValue JSC_HOST_CALL functionGetGetterSetter(ExecState* exec)
+{
+    JSValue value = exec->argument(0);
+    if (!value.isObject())
+        return JSValue::encode(jsUndefined());
+
+    JSValue property = exec->argument(1);
+    if (!property.isString())
+        return JSValue::encode(jsUndefined());
+
+    PropertySlot slot(value, PropertySlot::InternalMethodType::VMInquiry);
+    value.getPropertySlot(exec, asString(property)->toIdentifier(exec), slot);
+
+    JSValue result;
+    if (slot.isCacheableGetter())
+        result = slot.getterSetter();
+    else
+        result = jsNull();
+
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionVersion(ExecState*)
+{
     // We need this function for compatibility with the Mozilla JS tests but for now
     // we don't actually do any version-specific handling
     return JSValue::encode(jsUndefined());
 }
 
-EncodedJSValue JSC_HOST_CALL functionRun(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionRun(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String fileName = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    Vector<char> script;
+    if (!fetchScriptFromLocalFileSystem(fileName, script))
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Could not open file."))));
+
+    GlobalObject* globalObject = GlobalObject::create(vm, GlobalObject::createStructure(vm, jsNull()), Vector<String>());
+
+    JSArray* array = constructEmptyArray(globalObject->globalExec(), 0);
+    for (unsigned i = 1; i < exec->argumentCount(); ++i)
+        array->putDirectIndex(globalObject->globalExec(), i - 1, exec->uncheckedArgument(i));
+    globalObject->putDirect(
+        vm, Identifier::fromString(globalObject->globalExec(), "arguments"), array);
+
+    NakedPtr<Exception> exception;
+    StopWatch stopWatch;
+    stopWatch.start();
+    evaluate(globalObject->globalExec(), jscSource(script, SourceOrigin { absolutePath(fileName) }, fileName), JSValue(), exception);
+    stopWatch.stop();
+
+    if (exception) {
+        throwException(globalObject->globalExec(), scope, exception);
+        return JSValue::encode(jsUndefined());
+    }
+    
+    return JSValue::encode(jsNumber(stopWatch.getElapsedMS()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionRunString(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String source = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+
+    GlobalObject* globalObject = GlobalObject::create(vm, GlobalObject::createStructure(vm, jsNull()), Vector<String>());
+
+    JSArray* array = constructEmptyArray(globalObject->globalExec(), 0);
+    for (unsigned i = 1; i < exec->argumentCount(); ++i)
+        array->putDirectIndex(globalObject->globalExec(), i - 1, exec->uncheckedArgument(i));
+    globalObject->putDirect(
+        vm, Identifier::fromString(globalObject->globalExec(), "arguments"), array);
+
+    NakedPtr<Exception> exception;
+    evaluate(globalObject->globalExec(), makeSource(source, exec->callerSourceOrigin()), JSValue(), exception);
+
+    if (exception) {
+        scope.throwException(globalObject->globalExec(), exception);
+        return JSValue::encode(jsUndefined());
+    }
+    
+    return JSValue::encode(globalObject);
+}
+
+EncodedJSValue JSC_HOST_CALL functionLoad(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String fileName = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    Vector<char> script;
+    if (!fetchScriptFromLocalFileSystem(fileName, script))
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Could not open file."))));
+
+    JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+    
+    NakedPtr<Exception> evaluationException;
+    JSValue result = evaluate(globalObject->globalExec(), jscSource(script, SourceOrigin { absolutePath(fileName) }, fileName), JSValue(), evaluationException);
+    if (evaluationException)
+        throwException(exec, scope, evaluationException);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionLoadString(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String sourceCode = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+
+    NakedPtr<Exception> evaluationException;
+    JSValue result = evaluate(globalObject->globalExec(), makeSource(sourceCode, exec->callerSourceOrigin()), JSValue(), evaluationException);
+    if (evaluationException)
+        throwException(exec, scope, evaluationException);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionReadFile(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String fileName = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+
+    bool isBinary = false;
+    if (exec->argumentCount() > 1) {
+        String type = exec->argument(1).toWTFString(exec);
+        RETURN_IF_EXCEPTION(scope, encodedJSValue());
+        if (type != "binary")
+            return throwVMError(exec, scope, "Expected 'binary' as second argument.");
+        isBinary = true;
+    }
+
+    Vector<char> content;
+    if (!fillBufferWithContentsOfFile(fileName, content))
+        return throwVMError(exec, scope, "Could not open file.");
+
+    if (!isBinary)
+        return JSValue::encode(jsString(exec, stringFromUTF(content)));
+
+    Structure* structure = exec->lexicalGlobalObject()->typedArrayStructure(TypeUint8);
+    auto length = content.size();
+    JSObject* result = createUint8TypedArray(exec, structure, ArrayBuffer::createFromBytes(content.releaseBuffer().leakPtr(), length, [] (void* p) { fastFree(p); }), 0, length);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionCheckSyntax(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String fileName = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    Vector<char> script;
+    if (!fetchScriptFromLocalFileSystem(fileName, script))
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Could not open file."))));
+
+    JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+
+    StopWatch stopWatch;
+    stopWatch.start();
+
+    JSValue syntaxException;
+    bool validSyntax = checkSyntax(globalObject->globalExec(), jscSource(script, SourceOrigin { absolutePath(fileName) }, fileName), &syntaxException);
+    stopWatch.stop();
+
+    if (!validSyntax)
+        throwException(exec, scope, syntaxException);
+    return JSValue::encode(jsNumber(stopWatch.getElapsedMS()));
+}
+
+#if ENABLE(SAMPLING_FLAGS)
+EncodedJSValue JSC_HOST_CALL functionSetSamplingFlags(ExecState* exec)
+{
+    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
+        unsigned flag = static_cast<unsigned>(exec->uncheckedArgument(i).toNumber(exec));
+        if ((flag >= 1) && (flag <= 32))
+            SamplingFlags::setFlag(flag);
+    }
+    return JSValue::encode(jsNull());
+}
+
+EncodedJSValue JSC_HOST_CALL functionClearSamplingFlags(ExecState* exec)
+{
+    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
+        unsigned flag = static_cast<unsigned>(exec->uncheckedArgument(i).toNumber(exec));
+        if ((flag >= 1) && (flag <= 32))
+            SamplingFlags::clearFlag(flag);
+    }
+    return JSValue::encode(jsNull());
+}
+#endif
+
+EncodedJSValue JSC_HOST_CALL functionShadowChickenFunctionsOnStack(ExecState* exec)
+{
+    return JSValue::encode(exec->vm().shadowChicken().functionsOnStack(exec));
+}
+
+EncodedJSValue JSC_HOST_CALL functionSetGlobalConstRedeclarationShouldNotThrow(ExecState* exec)
+{
+    exec->vm().setGlobalConstRedeclarationShouldThrow(false);
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionGetRandomSeed(ExecState* exec)
+{
+    return JSValue::encode(jsNumber(exec->lexicalGlobalObject()->weakRandom().seed()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionSetRandomSeed(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    unsigned seed = exec->argument(0).toUInt32(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    exec->lexicalGlobalObject()->weakRandom().setSeed(seed);
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionIsRope(ExecState* exec)
+{
+    JSValue argument = exec->argument(0);
+    if (!argument.isString())
+        return JSValue::encode(jsBoolean(false));
+    const StringImpl* impl = asString(argument)->tryGetValueImpl();
+    return JSValue::encode(jsBoolean(!impl));
+}
+
+EncodedJSValue JSC_HOST_CALL functionCallerSourceOrigin(ExecState* state)
+{
+    SourceOrigin sourceOrigin = state->callerSourceOrigin();
+    if (sourceOrigin.isNull())
+        return JSValue::encode(jsNull());
+    return JSValue::encode(jsString(state, sourceOrigin.string()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionGlobalObjectForObject(ExecState* exec)
+{
+    JSValue value = exec->argument(0);
+    RELEASE_ASSERT(value.isObject());
+    JSGlobalObject* globalObject = jsCast<JSObject*>(value)->globalObject();
+    RELEASE_ASSERT(globalObject);
+    return JSValue::encode(globalObject);
+}
+
+EncodedJSValue JSC_HOST_CALL functionReadline(ExecState* exec)
+{
+    Vector<char, 256> line;
+    int c;
+    while ((c = getchar()) != EOF) {
+        // FIXME: Should we also break on \r? 
+        if (c == '\n')
+            break;
+        line.append(c);
+    }
+    line.append('\0');
+    return JSValue::encode(jsString(exec, line.data()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionPreciseTime(ExecState*)
+{
+    return JSValue::encode(jsNumber(currentTime()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionNeverInlineFunction(ExecState* exec)
+{
+    return JSValue::encode(setNeverInline(exec));
+}
+
+EncodedJSValue JSC_HOST_CALL functionNoDFG(ExecState* exec)
+{
+    return JSValue::encode(setNeverOptimize(exec));
+}
+
+EncodedJSValue JSC_HOST_CALL functionNoFTL(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    if (JSFunction* function = jsDynamicCast<JSFunction*>(vm, exec->argument(0))) {
+        FunctionExecutable* executable = function->jsExecutable();
+        executable->setNeverFTLOptimize(true);
+    }
+
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionNoOSRExitFuzzing(ExecState* exec)
 {
-    String fileName = exec->argument(0).toString(exec)->value(exec);
-    Vector<char> script;
-    if (!fillBufferWithContentsOfFile(fileName, script))
-        return JSValue::encode(exec->vm().throwException(exec, createError(exec, "Could not open file.")));
+    return JSValue::encode(setCannotUseOSRExitFuzzing(exec));
+}
+
+EncodedJSValue JSC_HOST_CALL functionOptimizeNextInvocation(ExecState* exec)
+{
+    return JSValue::encode(optimizeNextInvocation(exec));
+}
+
+EncodedJSValue JSC_HOST_CALL functionNumberOfDFGCompiles(ExecState* exec)
+{
+    return JSValue::encode(numberOfDFGCompiles(exec));
+}
+
+Message::Message(ArrayBufferContents&& contents, int32_t index)
+    : m_contents(WTFMove(contents))
+    , m_index(index)
+{
+}
+
+Message::~Message()
+{
+}
+
+Worker::Worker(Workers& workers)
+    : m_workers(workers)
+{
+    auto locker = holdLock(m_workers.m_lock);
+    m_workers.m_workers.append(this);
+    
+    *currentWorker() = this;
+}
+
+Worker::~Worker()
+{
+    auto locker = holdLock(m_workers.m_lock);
+    RELEASE_ASSERT(isOnList());
+    remove();
+}
+
+void Worker::enqueue(const AbstractLocker&, RefPtr<Message> message)
+{
+    m_messages.append(message);
+}
+
+RefPtr<Message> Worker::dequeue()
+{
+    auto locker = holdLock(m_workers.m_lock);
+    while (m_messages.isEmpty())
+        m_workers.m_condition.wait(m_workers.m_lock);
+    return m_messages.takeFirst();
+}
+
+Worker& Worker::current()
+{
+    return **currentWorker();
+}
+
+ThreadSpecific<Worker*>& Worker::currentWorker()
+{
+    static ThreadSpecific<Worker*>* result;
+    static std::once_flag flag;
+    std::call_once(
+        flag,
+        [] () {
+            result = new ThreadSpecific<Worker*>();
+        });
+    return *result;
+}
+
+Workers::Workers()
+{
+}
+
+Workers::~Workers()
+{
+    UNREACHABLE_FOR_PLATFORM();
+}
+
+template<typename Func>
+void Workers::broadcast(const Func& func)
+{
+    auto locker = holdLock(m_lock);
+    for (Worker* worker = m_workers.begin(); worker != m_workers.end(); worker = worker->next()) {
+        if (worker != &Worker::current())
+            func(locker, *worker);
+    }
+    m_condition.notifyAll();
+}
+
+void Workers::report(String string)
+{
+    auto locker = holdLock(m_lock);
+    m_reports.append(string.isolatedCopy());
+    m_condition.notifyAll();
+}
+
+String Workers::tryGetReport()
+{
+    auto locker = holdLock(m_lock);
+    if (m_reports.isEmpty())
+        return String();
+    return m_reports.takeFirst();
+}
+
+String Workers::getReport()
+{
+    auto locker = holdLock(m_lock);
+    while (m_reports.isEmpty())
+        m_condition.wait(m_lock);
+    return m_reports.takeFirst();
+}
+
+Workers& Workers::singleton()
+{
+    static Workers* result;
+    static std::once_flag flag;
+    std::call_once(
+        flag,
+        [] {
+            result = new Workers();
+        });
+    return *result;
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarCreateRealm(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    GlobalObject* result = GlobalObject::create(vm, GlobalObject::createStructure(vm, jsNull()), Vector<String>());
+    return JSValue::encode(result->getDirect(vm, Identifier::fromString(exec, "$")));
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarDetachArrayBuffer(ExecState* exec)
+{
+    return functionTransferArrayBuffer(exec);
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarEvalScript(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String sourceCode = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    
+    GlobalObject* globalObject = jsDynamicCast<GlobalObject*>(vm,
+        exec->thisValue().get(exec, Identifier::fromString(exec, "global")));
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    if (!globalObject)
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Expected global to point to a global object"))));
+    
+    NakedPtr<Exception> evaluationException;
+    JSValue result = evaluate(globalObject->globalExec(), makeSource(sourceCode, exec->callerSourceOrigin()), JSValue(), evaluationException);
+    if (evaluationException)
+        throwException(exec, scope, evaluationException);
+    return JSValue::encode(result);
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentStart(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String sourceCode = exec->argument(0).toWTFString(exec).isolatedCopy();
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    
+    Lock didStartLock;
+    Condition didStartCondition;
+    bool didStart = false;
+    
+    ThreadIdentifier thread = createThread(
+        "JSC Agent",
+        [sourceCode, &didStartLock, &didStartCondition, &didStart] () {
+            CommandLine commandLine(0, nullptr);
+            commandLine.m_interactive = false;
+            runJSC(
+                commandLine,
+                [&] (VM&, GlobalObject* globalObject) {
+                    // Notify the thread that started us that we have registered a worker.
+                    {
+                        auto locker = holdLock(didStartLock);
+                        didStart = true;
+                        didStartCondition.notifyOne();
+                    }
+                    
+                    NakedPtr<Exception> evaluationException;
+                    bool success = true;
+                    JSValue result;
+                    result = evaluate(globalObject->globalExec(), makeSource(sourceCode, SourceOrigin(ASCIILiteral("worker"))), JSValue(), evaluationException);
+                    if (evaluationException)
+                        result = evaluationException->value();
+                    checkException(globalObject, true, evaluationException, result, String(), false, false, success);
+                    if (!success)
+                        exit(1);
+                    return success;
+                });
+        });
+    detachThread(thread);
+    
+    {
+        auto locker = holdLock(didStartLock);
+        while (!didStart)
+            didStartCondition.wait(didStartLock);
+    }
+    
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentReceiveBroadcast(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    JSValue callback = exec->argument(0);
+    CallData callData;
+    CallType callType = getCallData(callback, callData);
+    if (callType == CallType::None)
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Expected callback"))));
+    
+    RefPtr<Message> message;
+    {
+        ReleaseHeapAccessScope releaseAccess(vm.heap);
+        message = Worker::current().dequeue();
+    }
+    
+    RefPtr<ArrayBuffer> nativeBuffer = ArrayBuffer::create(message->releaseContents());
+    ArrayBufferSharingMode sharingMode = nativeBuffer->sharingMode();
+    JSArrayBuffer* jsBuffer = JSArrayBuffer::create(vm, exec->lexicalGlobalObject()->arrayBufferStructure(sharingMode), WTFMove(nativeBuffer));
+    
+    MarkedArgumentBuffer args;
+    args.append(jsBuffer);
+    args.append(jsNumber(message->index()));
+    return JSValue::encode(call(exec, callback, callType, callData, jsNull(), args));
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentReport(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    String report = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    
+    Workers::singleton().report(report);
+    
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentSleep(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (exec->argumentCount() >= 1) {
+        Seconds seconds = Seconds::fromMilliseconds(exec->argument(0).toNumber(exec));
+        RETURN_IF_EXCEPTION(scope, encodedJSValue());
+        sleep(seconds);
+    }
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentBroadcast(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    JSArrayBuffer* jsBuffer = jsDynamicCast<JSArrayBuffer*>(vm, exec->argument(0));
+    if (!jsBuffer || !jsBuffer->isShared())
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Expected SharedArrayBuffer"))));
+    
+    int32_t index = exec->argument(1).toInt32(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    
+    Workers::singleton().broadcast(
+        [&] (const AbstractLocker& locker, Worker& worker) {
+            ArrayBuffer* nativeBuffer = jsBuffer->impl();
+            ArrayBufferContents contents;
+            nativeBuffer->transferTo(vm, contents); // "transferTo" means "share" if the buffer is shared.
+            RefPtr<Message> message = adoptRef(new Message(WTFMove(contents), index));
+            worker.enqueue(locker, message);
+        });
+    
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentGetReport(ExecState* exec)
+{
+    VM& vm = exec->vm();
+
+    String string = Workers::singleton().tryGetReport();
+    if (!string)
+        return JSValue::encode(jsNull());
+    
+    return JSValue::encode(jsString(&vm, string));
+}
+
+EncodedJSValue JSC_HOST_CALL functionDollarAgentLeaving(ExecState*)
+{
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionWaitForReport(ExecState* exec)
+{
+    VM& vm = exec->vm();
+
+    String string;
+    {
+        ReleaseHeapAccessScope releaseAccess(vm.heap);
+        string = Workers::singleton().getReport();
+    }
+    if (!string)
+        return JSValue::encode(jsNull());
+    
+    return JSValue::encode(jsString(&vm, string));
+}
+
+EncodedJSValue JSC_HOST_CALL functionHeapCapacity(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    return JSValue::encode(jsNumber(vm.heap.capacity()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionFlashHeapAccess(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+    
+    vm.heap.releaseAccess();
+    if (exec->argumentCount() >= 1) {
+        double ms = exec->argument(0).toNumber(exec);
+        RETURN_IF_EXCEPTION(scope, encodedJSValue());
+        sleep(Seconds::fromMilliseconds(ms));
+    }
+    vm.heap.acquireAccess();
+    return JSValue::encode(jsUndefined());
+}
+
+template<typename ValueType>
+typename std::enable_if<!std::is_fundamental<ValueType>::value>::type addOption(VM&, JSObject*, Identifier, ValueType) { }
+
+template<typename ValueType>
+typename std::enable_if<std::is_fundamental<ValueType>::value>::type addOption(VM& vm, JSObject* optionsObject, Identifier identifier, ValueType value)
+{
+    optionsObject->putDirect(vm, identifier, JSValue(value));
+}
+
+EncodedJSValue JSC_HOST_CALL functionJSCOptions(ExecState* exec)
+{
+    JSObject* optionsObject = constructEmptyObject(exec);
+#define FOR_EACH_OPTION(type_, name_, defaultValue_, availability_, description_) \
+    addOption(exec->vm(), optionsObject, Identifier::fromString(exec, #name_), Options::name_());
+    JSC_OPTIONS(FOR_EACH_OPTION)
+#undef FOR_EACH_OPTION
+    return JSValue::encode(optionsObject);
+}
+
+EncodedJSValue JSC_HOST_CALL functionReoptimizationRetryCount(ExecState* exec)
+{
+    if (exec->argumentCount() < 1)
+        return JSValue::encode(jsUndefined());
+    
+    CodeBlock* block = getSomeBaselineCodeBlockForFunction(exec->argument(0));
+    if (!block)
+        return JSValue::encode(jsNumber(0));
+    
+    return JSValue::encode(jsNumber(block->reoptimizationRetryCounter()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionTransferArrayBuffer(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (exec->argumentCount() < 1)
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Not enough arguments"))));
+    
+    JSArrayBuffer* buffer = jsDynamicCast<JSArrayBuffer*>(vm, exec->argument(0));
+    if (!buffer)
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Expected an array buffer"))));
+    
+    ArrayBufferContents dummyContents;
+    buffer->impl()->transferTo(vm, dummyContents);
+    
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionFailNextNewCodeBlock(ExecState* exec)
+{
+    exec->vm().setFailNextNewCodeBlock();
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionQuit(ExecState*)
+{
+    jscExit(EXIT_SUCCESS);
+
+#if COMPILER(MSVC)
+    // Without this, Visual Studio will complain that this method does not return a value.
+    return JSValue::encode(jsUndefined());
+#endif
+}
+
+EncodedJSValue JSC_HOST_CALL functionAbort(ExecState*)
+{
+    CRASH();
+}
+
+EncodedJSValue JSC_HOST_CALL functionFalse1(ExecState*) { return JSValue::encode(jsBoolean(false)); }
+EncodedJSValue JSC_HOST_CALL functionFalse2(ExecState*) { return JSValue::encode(jsBoolean(false)); }
+
+EncodedJSValue JSC_HOST_CALL functionUndefined1(ExecState*) { return JSValue::encode(jsUndefined()); }
+EncodedJSValue JSC_HOST_CALL functionUndefined2(ExecState*) { return JSValue::encode(jsUndefined()); }
+EncodedJSValue JSC_HOST_CALL functionIsInt32(ExecState* exec)
+{
+    for (size_t i = 0; i < exec->argumentCount(); ++i) {
+        if (!exec->argument(i).isInt32())
+            return JSValue::encode(jsBoolean(false));
+    }
+    return JSValue::encode(jsBoolean(true));
+}
+
+EncodedJSValue JSC_HOST_CALL functionIdentity(ExecState* exec) { return JSValue::encode(exec->argument(0)); }
+
+EncodedJSValue JSC_HOST_CALL functionEffectful42(ExecState*)
+{
+    return JSValue::encode(jsNumber(42));
+}
+
+EncodedJSValue JSC_HOST_CALL functionMakeMasquerader(ExecState* exec)
+{
+    return JSValue::encode(Masquerader::create(exec->vm(), exec->lexicalGlobalObject()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionHasCustomProperties(ExecState* exec)
+{
+    JSValue value = exec->argument(0);
+    if (value.isObject())
+        return JSValue::encode(jsBoolean(asObject(value)->hasCustomProperties()));
+    return JSValue::encode(jsBoolean(false));
+}
+
+EncodedJSValue JSC_HOST_CALL functionDumpTypesForAllVariables(ExecState* exec)
+{
+    exec->vm().dumpTypeProfilerData();
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionFindTypeForExpression(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    RELEASE_ASSERT(exec->vm().typeProfiler());
+    vm.typeProfilerLog()->processLogEntries(ASCIILiteral("jsc Testing API: functionFindTypeForExpression"));
+
+    JSValue functionValue = exec->argument(0);
+    RELEASE_ASSERT(functionValue.isFunction());
+    FunctionExecutable* executable = (jsDynamicCast<JSFunction*>(vm, functionValue.asCell()->getObject()))->jsExecutable();
+
+    RELEASE_ASSERT(exec->argument(1).isString());
+    String substring = asString(exec->argument(1))->value(exec);
+    String sourceCodeText = executable->source().view().toString();
+    unsigned offset = static_cast<unsigned>(sourceCodeText.find(substring) + executable->source().startOffset());
+    
+    String jsonString = exec->vm().typeProfiler()->typeInformationForExpressionAtOffset(TypeProfilerSearchDescriptorNormal, offset, executable->sourceID(), exec->vm());
+    return JSValue::encode(JSONParse(exec, jsonString));
+}
+
+EncodedJSValue JSC_HOST_CALL functionReturnTypeFor(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    RELEASE_ASSERT(exec->vm().typeProfiler());
+    vm.typeProfilerLog()->processLogEntries(ASCIILiteral("jsc Testing API: functionReturnTypeFor"));
+
+    JSValue functionValue = exec->argument(0);
+    RELEASE_ASSERT(functionValue.isFunction());
+    FunctionExecutable* executable = (jsDynamicCast<JSFunction*>(vm, functionValue.asCell()->getObject()))->jsExecutable();
+
+    unsigned offset = executable->typeProfilingStartOffset();
+    String jsonString = exec->vm().typeProfiler()->typeInformationForExpressionAtOffset(TypeProfilerSearchDescriptorFunctionReturn, offset, executable->sourceID(), exec->vm());
+    return JSValue::encode(JSONParse(exec, jsonString));
+}
+
+EncodedJSValue JSC_HOST_CALL functionDumpBasicBlockExecutionRanges(ExecState* exec)
+{
+    RELEASE_ASSERT(exec->vm().controlFlowProfiler());
+    exec->vm().controlFlowProfiler()->dumpData();
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionHasBasicBlockExecuted(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    RELEASE_ASSERT(vm.controlFlowProfiler());
+
+    JSValue functionValue = exec->argument(0);
+    RELEASE_ASSERT(functionValue.isFunction());
+    FunctionExecutable* executable = (jsDynamicCast<JSFunction*>(vm, functionValue.asCell()->getObject()))->jsExecutable();
+
+    RELEASE_ASSERT(exec->argument(1).isString());
+    String substring = asString(exec->argument(1))->value(exec);
+    String sourceCodeText = executable->source().view().toString();
+    RELEASE_ASSERT(sourceCodeText.contains(substring));
+    int offset = sourceCodeText.find(substring) + executable->source().startOffset();
+    
+    bool hasExecuted = vm.controlFlowProfiler()->hasBasicBlockAtTextOffsetBeenExecuted(offset, executable->sourceID(), vm);
+    return JSValue::encode(jsBoolean(hasExecuted));
+}
+
+EncodedJSValue JSC_HOST_CALL functionBasicBlockExecutionCount(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    RELEASE_ASSERT(vm.controlFlowProfiler());
+
+    JSValue functionValue = exec->argument(0);
+    RELEASE_ASSERT(functionValue.isFunction());
+    FunctionExecutable* executable = (jsDynamicCast<JSFunction*>(vm, functionValue.asCell()->getObject()))->jsExecutable();
+
+    RELEASE_ASSERT(exec->argument(1).isString());
+    String substring = asString(exec->argument(1))->value(exec);
+    String sourceCodeText = executable->source().view().toString();
+    RELEASE_ASSERT(sourceCodeText.contains(substring));
+    int offset = sourceCodeText.find(substring) + executable->source().startOffset();
+    
+    size_t executionCount = vm.controlFlowProfiler()->basicBlockExecutionCountAtTextOffset(offset, executable->sourceID(), exec->vm());
+    return JSValue::encode(JSValue(executionCount));
+}
+
+EncodedJSValue JSC_HOST_CALL functionEnableExceptionFuzz(ExecState*)
+{
+    Options::useExceptionFuzz() = true;
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionDrainMicrotasks(ExecState* exec)
+{
+    exec->vm().drainMicrotasks();
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionIs32BitPlatform(ExecState*)
+{
+#if USE(JSVALUE64)
+    return JSValue::encode(JSValue(JSC::JSValue::JSFalse));
+#else
+    return JSValue::encode(JSValue(JSC::JSValue::JSTrue));
+#endif
+}
 
-    GlobalObject* globalObject = GlobalObject::create(exec->vm(), GlobalObject::createStructure(exec->vm(), jsNull()), Vector<String>());
+EncodedJSValue JSC_HOST_CALL functionLoadModule(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
 
-    JSArray* array = constructEmptyArray(globalObject->globalExec(), 0);
-    for (unsigned i = 1; i < exec->argumentCount(); ++i)
-        array->putDirectIndex(globalObject->globalExec(), i - 1, exec->uncheckedArgument(i));
-    globalObject->putDirect(
-        exec->vm(), Identifier(globalObject->globalExec(), "arguments"), array);
+    String fileName = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+    Vector<char> script;
+    if (!fetchScriptFromLocalFileSystem(fileName, script))
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Could not open file."))));
 
-    JSValue exception;
-    StopWatch stopWatch;
-    stopWatch.start();
-    evaluate(globalObject->globalExec(), jscSource(script.data(), fileName), JSValue(), &exception);
-    stopWatch.stop();
+    JSInternalPromise* promise = loadAndEvaluateModule(exec, fileName);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
 
-    if (!!exception) {
-        exec->vm().throwException(globalObject->globalExec(), exception);
+    JSValue error;
+    JSFunction* errorHandler = JSNativeStdFunction::create(vm, exec->lexicalGlobalObject(), 1, String(), [&](ExecState* exec) {
+        error = exec->argument(0);
         return JSValue::encode(jsUndefined());
-    }
-    
-    return JSValue::encode(jsNumber(stopWatch.getElapsedMS()));
+    });
+
+    promise->then(exec, nullptr, errorHandler);
+    vm.drainMicrotasks();
+    if (error)
+        return JSValue::encode(throwException(exec, scope, error));
+    return JSValue::encode(jsUndefined());
 }
 
-EncodedJSValue JSC_HOST_CALL functionLoad(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionCreateBuiltin(ExecState* exec)
 {
-    String fileName = exec->argument(0).toString(exec)->value(exec);
-    Vector<char> script;
-    if (!fillBufferWithContentsOfFile(fileName, script))
-        return JSValue::encode(exec->vm().throwException(exec, createError(exec, "Could not open file.")));
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
 
-    JSGlobalObject* globalObject = exec->lexicalGlobalObject();
-    
-    JSValue evaluationException;
-    JSValue result = evaluate(globalObject->globalExec(), jscSource(script.data(), fileName), JSValue(), &evaluationException);
-    if (evaluationException)
-        exec->vm().throwException(exec, evaluationException);
-    return JSValue::encode(result);
+    if (exec->argumentCount() < 1 || !exec->argument(0).isString())
+        return JSValue::encode(jsUndefined());
+
+    String functionText = asString(exec->argument(0))->value(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
+
+    const SourceCode& source = makeSource(functionText, { });
+    JSFunction* func = JSFunction::createBuiltinFunction(vm, createBuiltinExecutable(vm, source, Identifier::fromString(&vm, "foo"), ConstructorKind::None, ConstructAbility::CannotConstruct)->link(vm, source), exec->lexicalGlobalObject());
+
+    return JSValue::encode(func);
 }
 
-EncodedJSValue JSC_HOST_CALL functionReadFile(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionCreateGlobalObject(ExecState* exec)
 {
-    String fileName = exec->argument(0).toString(exec)->value(exec);
-    Vector<char> script;
-    if (!fillBufferWithContentsOfFile(fileName, script))
-        return JSValue::encode(exec->vm().throwException(exec, createError(exec, "Could not open file.")));
-
-    return JSValue::encode(jsString(exec, stringFromUTF(script.data())));
+    VM& vm = exec->vm();
+    return JSValue::encode(GlobalObject::create(vm, GlobalObject::createStructure(vm, jsNull()), Vector<String>()));
 }
 
-EncodedJSValue JSC_HOST_CALL functionCheckSyntax(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionCheckModuleSyntax(ExecState* exec)
 {
-    String fileName = exec->argument(0).toString(exec)->value(exec);
-    Vector<char> script;
-    if (!fillBufferWithContentsOfFile(fileName, script))
-        return JSValue::encode(exec->vm().throwException(exec, createError(exec, "Could not open file.")));
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
 
-    JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+    String source = exec->argument(0).toWTFString(exec);
+    RETURN_IF_EXCEPTION(scope, encodedJSValue());
 
     StopWatch stopWatch;
     stopWatch.start();
 
-    JSValue syntaxException;
-    bool validSyntax = checkSyntax(globalObject->globalExec(), jscSource(script.data(), fileName), &syntaxException);
+    ParserError error;
+    bool validSyntax = checkModuleSyntax(exec, makeSource(source, { }, String(), TextPosition(), SourceProviderSourceType::Module), error);
     stopWatch.stop();
 
     if (!validSyntax)
-        exec->vm().throwException(exec, syntaxException);
+        throwException(exec, scope, jsNontrivialString(exec, toString("SyntaxError: ", error.message(), ":", error.line())));
     return JSValue::encode(jsNumber(stopWatch.getElapsedMS()));
 }
 
-#if ENABLE(SAMPLING_FLAGS)
-EncodedJSValue JSC_HOST_CALL functionSetSamplingFlags(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionPlatformSupportsSamplingProfiler(ExecState*)
 {
-    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
-        unsigned flag = static_cast<unsigned>(exec->uncheckedArgument(i).toNumber(exec));
-        if ((flag >= 1) && (flag <= 32))
-            SamplingFlags::setFlag(flag);
-    }
-    return JSValue::encode(jsNull());
+#if ENABLE(SAMPLING_PROFILER)
+    return JSValue::encode(JSValue(JSC::JSValue::JSTrue));
+#else
+    return JSValue::encode(JSValue(JSC::JSValue::JSFalse));
+#endif
 }
 
-EncodedJSValue JSC_HOST_CALL functionClearSamplingFlags(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionGenerateHeapSnapshot(ExecState* exec)
 {
-    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
-        unsigned flag = static_cast<unsigned>(exec->uncheckedArgument(i).toNumber(exec));
-        if ((flag >= 1) && (flag <= 32))
-            SamplingFlags::clearFlag(flag);
-    }
-    return JSValue::encode(jsNull());
+    VM& vm = exec->vm();
+    JSLockHolder lock(vm);
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    HeapSnapshotBuilder snapshotBuilder(exec->vm().ensureHeapProfiler());
+    snapshotBuilder.buildSnapshot();
+
+    String jsonString = snapshotBuilder.json();
+    EncodedJSValue result = JSValue::encode(JSONParse(exec, jsonString));
+    RELEASE_ASSERT(!scope.exception());
+    return result;
 }
-#endif
 
-EncodedJSValue JSC_HOST_CALL functionReadline(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionResetSuperSamplerState(ExecState*)
 {
-    Vector<char, 256> line;
-    int c;
-    while ((c = getchar()) != EOF) {
-        // FIXME: Should we also break on \r? 
-        if (c == '\n')
-            break;
-        line.append(c);
+    resetSuperSamplerState();
+    return JSValue::encode(jsUndefined());
+}
+
+EncodedJSValue JSC_HOST_CALL functionEnsureArrayStorage(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    for (unsigned i = 0; i < exec->argumentCount(); ++i) {
+        if (JSObject* object = jsDynamicCast<JSObject*>(vm, exec->argument(0)))
+            object->ensureArrayStorage(exec->vm());
     }
-    line.append('\0');
-    return JSValue::encode(jsString(exec, line.data()));
+    return JSValue::encode(jsUndefined());
 }
 
-EncodedJSValue JSC_HOST_CALL functionPreciseTime(ExecState*)
+#if ENABLE(SAMPLING_PROFILER)
+EncodedJSValue JSC_HOST_CALL functionStartSamplingProfiler(ExecState* exec)
 {
-    return JSValue::encode(jsNumber(currentTime()));
+    SamplingProfiler& samplingProfiler = exec->vm().ensureSamplingProfiler(WTF::Stopwatch::create());
+    samplingProfiler.noticeCurrentThreadAsJSCExecutionThread();
+    samplingProfiler.start();
+    return JSValue::encode(jsUndefined());
 }
 
-EncodedJSValue JSC_HOST_CALL functionNeverInlineFunction(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionSamplingProfilerStackTraces(ExecState* exec)
 {
-    return JSValue::encode(setNeverInline(exec));
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (!vm.samplingProfiler())
+        return JSValue::encode(throwException(exec, scope, createError(exec, ASCIILiteral("Sampling profiler was never started"))));
+
+    String jsonString = vm.samplingProfiler()->stackTracesAsJSON();
+    EncodedJSValue result = JSValue::encode(JSONParse(exec, jsonString));
+    RELEASE_ASSERT(!scope.exception());
+    return result;
 }
+#endif // ENABLE(SAMPLING_PROFILER)
 
-EncodedJSValue JSC_HOST_CALL functionNumberOfDFGCompiles(ExecState* exec)
+EncodedJSValue JSC_HOST_CALL functionMaxArguments(ExecState*)
 {
-    return JSValue::encode(numberOfDFGCompiles(exec));
+    return JSValue::encode(jsNumber(JSC::maxArguments));
 }
 
-EncodedJSValue JSC_HOST_CALL functionTransferArrayBuffer(ExecState* exec)
+#if ENABLE(WEBASSEMBLY)
+
+static CString valueWithTypeOfWasmValue(ExecState* exec, VM& vm, JSValue value, JSValue wasmValue)
 {
-    if (exec->argumentCount() < 1)
-        return JSValue::encode(exec->vm().throwException(exec, createError(exec, "Not enough arguments")));
-    
-    JSArrayBuffer* buffer = jsDynamicCast<JSArrayBuffer*>(exec->argument(0));
-    if (!buffer)
-        return JSValue::encode(exec->vm().throwException(exec, createError(exec, "Expected an array buffer")));
-    
-    ArrayBufferContents dummyContents;
-    buffer->impl()->transfer(dummyContents);
-    
-    return JSValue::encode(jsUndefined());
+    JSString* type = asString(wasmValue.get(exec, makeIdentifier(vm, "type")));
+
+    const String& typeString = type->value(exec);
+    if (typeString == "i64" || typeString == "i32")
+        return toCString(typeString, " ", RawPointer(bitwise_cast<void*>(value)));
+    if (typeString == "f32")
+        return toCString(typeString, " hex: ", RawPointer(bitwise_cast<void*>(value)), ", float: ", bitwise_cast<float>(static_cast<uint32_t>(JSValue::encode(value))));
+    return toCString(typeString, " hex: ", RawPointer(bitwise_cast<void*>(value)), ", double: ", bitwise_cast<double>(value));
 }
 
-EncodedJSValue JSC_HOST_CALL functionQuit(ExecState*)
+static JSValue box(ExecState* exec, VM& vm, JSValue wasmValue)
 {
-    exit(EXIT_SUCCESS);
 
-#if COMPILER(MSVC) && OS(WINCE)
-    // Without this, Visual Studio will complain that this method does not return a value.
-    return JSValue::encode(jsUndefined());
+    JSString* type = asString(wasmValue.get(exec, makeIdentifier(vm, "type")));
+    JSValue value = wasmValue.get(exec, makeIdentifier(vm, "value"));
+
+    auto unboxString = [&] (const char* hexFormat, const char* decFormat, auto& result) {
+        if (!value.isString())
+            return false;
+
+        const char* str = toCString(asString(value)->value(exec)).data();
+        int scanResult;
+        int length = std::strlen(str);
+        if ((length > 2 && (str[0] == '0' && str[1] == 'x'))
+            || (length > 3 && (str[0] == '-' && str[1] == '0' && str[2] == 'x')))
+#if COMPILER(CLANG)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
+#endif
+            scanResult = sscanf(str, hexFormat, &result);
+        else
+            scanResult = sscanf(str, decFormat, &result);
+#if COMPILER(CLANG)
+#pragma clang diagnostic pop
 #endif
+        RELEASE_ASSERT(scanResult != EOF);
+        return true;
+    };
+
+    const String& typeString = type->value(exec);
+    if (typeString == "i64") {
+        int64_t result;
+        if (!unboxString("%llx", "%lld", result))
+            CRASH();
+        return JSValue::decode(result);
+    }
+
+    if (typeString == "i32") {
+        int32_t result;
+        if (!unboxString("%x", "%d", result))
+            result = value.asInt32();
+        return JSValue::decode(static_cast<uint32_t>(result));
+    }
+
+    if (typeString == "f32") {
+        float result;
+        if (!unboxString("%a", "%f", result))
+            result = value.toFloat(exec);
+        return JSValue::decode(bitwise_cast<uint32_t>(result));
+    }
+
+    RELEASE_ASSERT(typeString == "f64");
+    double result;
+    if (!unboxString("%la", "%lf", result))
+        result = value.asNumber();
+    return JSValue::decode(bitwise_cast<uint64_t>(result));
+}
+
+// FIXME: https://bugs.webkit.org/show_bug.cgi?id=168582.
+static JSValue callWasmFunction(VM* vm, JSGlobalObject* globalObject, JSWebAssemblyCallee* wasmCallee, const ArgList& boxedArgs)
+{
+    JSValue firstArgument;
+    int argCount = 1;
+    JSValue* remainingArgs = nullptr;
+    if (boxedArgs.size()) {
+        remainingArgs = boxedArgs.data();
+        firstArgument = *remainingArgs;
+        remainingArgs++;
+        argCount = boxedArgs.size();
+    }
+
+    ProtoCallFrame protoCallFrame;
+    protoCallFrame.init(nullptr, globalObject->globalExec()->jsCallee(), firstArgument, argCount, remainingArgs);
+
+    return JSValue::decode(vmEntryToWasm(wasmCallee->entrypoint(), vm, &protoCallFrame));
+}
+
+// testWasmModule(JSArrayBufferView source, number functionCount, ...[[WasmValue, [WasmValue]]]) where the ith copy of [[result, [args]]] is a list
+// of arguments to be passed to the ith wasm function as well as the expected result. WasmValue is an object with "type" and "value" properties.
+static EncodedJSValue JSC_HOST_CALL functionTestWasmModuleFunctions(ExecState* exec)
+{
+    VM& vm = exec->vm();
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (!Options::useWebAssembly())
+        return throwVMTypeError(exec, scope, ASCIILiteral("testWasmModule should only be called if the useWebAssembly option is set"));
+
+    JSArrayBufferView* source = jsCast<JSArrayBufferView*>(exec->argument(0));
+    uint32_t functionCount = exec->argument(1).toUInt32(exec);
+
+    if (exec->argumentCount() != functionCount + 2)
+        CRASH();
+
+    Wasm::Plan plan(&vm, static_cast<uint8_t*>(source->vector()), source->length());
+    plan.run();
+    if (plan.failed()) {
+        dataLogLn("failed to parse module: ", plan.errorMessage());
+        CRASH();
+    }
+
+    if (plan.internalFunctionCount() != functionCount)
+        CRASH();
+
+    MarkedArgumentBuffer callees;
+    MarkedArgumentBuffer keepAlive;
+    {
+        unsigned lastIndex = UINT_MAX;
+        plan.initializeCallees(exec->lexicalGlobalObject(),
+            [&] (unsigned calleeIndex, JSWebAssemblyCallee* jsEntrypointCallee, JSWebAssemblyCallee* wasmEntrypointCallee) {
+                RELEASE_ASSERT(!calleeIndex || (calleeIndex - 1 == lastIndex));
+                callees.append(jsEntrypointCallee);
+                keepAlive.append(wasmEntrypointCallee);
+                lastIndex = calleeIndex;
+            });
+    }
+    std::unique_ptr<Wasm::ModuleInformation> moduleInformation = plan.takeModuleInformation();
+    RELEASE_ASSERT(!moduleInformation->memory);
+
+    for (uint32_t i = 0; i < functionCount; ++i) {
+        JSArray* testCases = jsCast<JSArray*>(exec->argument(i + 2));
+        for (unsigned testIndex = 0; testIndex < testCases->length(); ++testIndex) {
+            JSArray* test = jsCast<JSArray*>(testCases->getIndexQuickly(testIndex));
+            JSObject* result = jsCast<JSObject*>(test->getIndexQuickly(0));
+            JSArray* arguments = jsCast<JSArray*>(test->getIndexQuickly(1));
+
+            MarkedArgumentBuffer boxedArgs;
+            for (unsigned argIndex = 0; argIndex < arguments->length(); ++argIndex)
+                boxedArgs.append(box(exec, vm, arguments->getIndexQuickly(argIndex)));
+
+            JSValue callResult;
+            {
+                auto scope = DECLARE_THROW_SCOPE(vm);
+                callResult = callWasmFunction(&vm, exec->lexicalGlobalObject(), jsCast<JSWebAssemblyCallee*>(callees.at(i)), boxedArgs);
+                RETURN_IF_EXCEPTION(scope, { });
+            }
+            JSValue expected = box(exec, vm, result);
+            if (callResult != expected) {
+                dataLog("Arguments: ");
+                CommaPrinter comma(", ");
+                for (unsigned argIndex = 0; argIndex < arguments->length(); ++argIndex)
+                    dataLog(comma, valueWithTypeOfWasmValue(exec, vm, boxedArgs.at(argIndex), arguments->getIndexQuickly(argIndex)));
+                dataLogLn();
+
+                WTFReportAssertionFailure(__FILE__, __LINE__, WTF_PRETTY_FUNCTION, toCString(" (callResult == ", valueWithTypeOfWasmValue(exec, vm, callResult, result), ", expected == ", valueWithTypeOfWasmValue(exec, vm, expected, result), ")").data());
+                CRASH();
+            }
+        }
+    }
+
+    return encodedJSUndefined();
 }
 
+#endif // ENABLE(WEBASSEBLY)
+
 // Use SEH for Release builds only to get rid of the crash report dialog
 // (luckily the same tests fail in Release and Debug builds so far). Need to
 // be in a separate main function because the jscmain function requires object
 // unwinding.
 
-#if COMPILER(MSVC) && !defined(_DEBUG) && !OS(WINCE)
+#if COMPILER(MSVC) && !defined(_DEBUG)
 #define TRY       __try {
 #define EXCEPT(x) } __except (EXCEPTION_EXECUTE_HANDLER) { x; }
 #else
@@ -546,16 +3197,27 @@ EncodedJSValue JSC_HOST_CALL functionQuit(ExecState*)
 int jscmain(int argc, char** argv);
 
 static double s_desiredTimeout;
+static double s_timeoutMultiplier = 1.0;
 
 static NO_RETURN_DUE_TO_CRASH void timeoutThreadMain(void*)
 {
-    auto timeout = std::chrono::microseconds(static_cast<std::chrono::microseconds::rep>(s_desiredTimeout * 1000000));
-    std::this_thread::sleep_for(timeout);
-    
-    dataLog("Timed out after ", s_desiredTimeout, " seconds!\n");
+    Seconds timeoutDuration(s_desiredTimeout * s_timeoutMultiplier);
+    sleep(timeoutDuration);
+    dataLog("Timed out after ", timeoutDuration, " seconds!\n");
     CRASH();
 }
 
+static void startTimeoutThreadIfNeeded()
+{
+    if (char* timeoutString = getenv("JSCTEST_timeout")) {
+        if (sscanf(timeoutString, "%lf", &s_desiredTimeout) != 1) {
+            dataLog("WARNING: timeout string is malformed, got ", timeoutString,
+                " but expected a number. Not using a timeout.\n");
+        } else
+            createThread(timeoutThreadMain, 0, "jsc Timeout Thread");
+    }
+}
+
 int main(int argc, char** argv)
 {
 #if PLATFORM(IOS) && CPU(ARM_THUMB2)
@@ -567,7 +3229,6 @@ int main(int argc, char** argv)
 #endif
 
 #if OS(WINDOWS)
-#if !OS(WINCE)
     // Cygwin calls ::SetErrorMode(SEM_FAILCRITICALERRORS), which we will inherit. This is bad for
     // testing/debugging, as it causes the post-mortem debugger not to be invoked. We reset the
     // error mode here to work around Cygwin's behavior. See <http://webkit.org/b/55222>.
@@ -580,32 +3241,20 @@ int main(int argc, char** argv)
     _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE);
     _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
     _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE);
-#endif
 #endif
 
     timeBeginPeriod(1);
 #endif
 
-#if PLATFORM(EFL)
-    ecore_init();
-#endif
-
-    // Initialize JSC before getting VM.
-#if ENABLE(SAMPLING_REGIONS)
-    WTF::initializeMainThread();
+#if PLATFORM(GTK)
+    if (!setlocale(LC_ALL, ""))
+        WTFLogAlways("Locale not supported by C library.\n\tUsing the fallback 'C' locale.");
 #endif
-    JSC::initializeThreading();
 
-#if !OS(WINCE)
-    if (char* timeoutString = getenv("JSC_timeout")) {
-        if (sscanf(timeoutString, "%lf", &s_desiredTimeout) != 1) {
-            dataLog(
-                "WARNING: timeout string is malformed, got ", timeoutString,
-                " but expected a number. Not using a timeout.\n");
-        } else
-            createThread(timeoutThreadMain, 0, "jsc Timeout Thread");
-    }
-#endif
+    // Need to initialize WTF threading before we start any threads. Cannot initialize JSC
+    // threading yet, since that would do somethings that we'd like to defer until after we
+    // have a chance to parse options.
+    WTF::initializeThreading();
 
 #if PLATFORM(IOS)
     Options::crashIfCantAllocateJITMemory() = true;
@@ -617,19 +3266,100 @@ int main(int argc, char** argv)
     TRY
         res = jscmain(argc, argv);
     EXCEPT(res = 3)
-    if (Options::logHeapStatisticsAtExit())
-        HeapStatistics::reportSuccess();
+    finalizeStatsAtEndOfTesting();
 
-#if PLATFORM(EFL)
-    ecore_shutdown();
-#endif
+    jscExit(res);
+}
+
+static void dumpException(GlobalObject* globalObject, JSValue exception)
+{
+    VM& vm = globalObject->vm();
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+
+#define CHECK_EXCEPTION() do { \
+        if (scope.exception()) { \
+            scope.clearException(); \
+            return; \
+        } \
+    } while (false)
+
+    printf("Exception: %s\n", exception.toWTFString(globalObject->globalExec()).utf8().data());
+
+    Identifier nameID = Identifier::fromString(globalObject->globalExec(), "name");
+    Identifier fileNameID = Identifier::fromString(globalObject->globalExec(), "sourceURL");
+    Identifier lineNumberID = Identifier::fromString(globalObject->globalExec(), "line");
+    Identifier stackID = Identifier::fromString(globalObject->globalExec(), "stack");
+    
+    JSValue nameValue = exception.get(globalObject->globalExec(), nameID);
+    CHECK_EXCEPTION();
+    JSValue fileNameValue = exception.get(globalObject->globalExec(), fileNameID);
+    CHECK_EXCEPTION();
+    JSValue lineNumberValue = exception.get(globalObject->globalExec(), lineNumberID);
+    CHECK_EXCEPTION();
+    JSValue stackValue = exception.get(globalObject->globalExec(), stackID);
+    CHECK_EXCEPTION();
+    
+    if (nameValue.toWTFString(globalObject->globalExec()) == "SyntaxError"
+        && (!fileNameValue.isUndefinedOrNull() || !lineNumberValue.isUndefinedOrNull())) {
+        printf(
+            "at %s:%s\n",
+            fileNameValue.toWTFString(globalObject->globalExec()).utf8().data(),
+            lineNumberValue.toWTFString(globalObject->globalExec()).utf8().data());
+    }
+    
+    if (!stackValue.isUndefinedOrNull())
+        printf("%s\n", stackValue.toWTFString(globalObject->globalExec()).utf8().data());
+
+#undef CHECK_EXCEPTION
+}
+
+static bool checkUncaughtException(VM& vm, GlobalObject* globalObject, JSValue exception, const String& expectedExceptionName, bool alwaysDumpException)
+{
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+    scope.clearException();
+    if (!exception) {
+        printf("Expected uncaught exception with name '%s' but none was thrown\n", expectedExceptionName.utf8().data());
+        return false;
+    }
+
+    ExecState* exec = globalObject->globalExec();
+    JSValue exceptionClass = globalObject->get(exec, Identifier::fromString(exec, expectedExceptionName));
+    if (!exceptionClass.isObject() || scope.exception()) {
+        printf("Expected uncaught exception with name '%s' but given exception class is not defined\n", expectedExceptionName.utf8().data());
+        return false;
+    }
+
+    bool isInstanceOfExpectedException = jsCast<JSObject*>(exceptionClass)->hasInstance(exec, exception);
+    if (scope.exception()) {
+        printf("Expected uncaught exception with name '%s' but given exception class fails performing hasInstance\n", expectedExceptionName.utf8().data());
+        return false;
+    }
+    if (isInstanceOfExpectedException) {
+        if (alwaysDumpException)
+            dumpException(globalObject, exception);
+        return true;
+    }
+
+    printf("Expected uncaught exception with name '%s' but exception value is not instance of this exception class\n", expectedExceptionName.utf8().data());
+    dumpException(globalObject, exception);
+    return false;
+}
 
-    return res;
+static void checkException(GlobalObject* globalObject, bool isLastFile, bool hasException, JSValue value, const String& uncaughtExceptionName, bool alwaysDumpUncaughtException, bool dump, bool& success)
+{
+    VM& vm = globalObject->vm();
+    if (!uncaughtExceptionName || !isLastFile) {
+        success = success && !hasException;
+        if (dump && !hasException)
+            printf("End: %s\n", value.toWTFString(globalObject->globalExec()).utf8().data());
+        if (hasException)
+            dumpException(globalObject, value);
+    } else
+        success = success && checkUncaughtException(vm, globalObject, (hasException) ? value : JSValue(), uncaughtExceptionName, alwaysDumpUncaughtException);
 }
 
-static bool runWithScripts(GlobalObject* globalObject, const Vector<Script>& scripts, bool dump)
+static bool runWithScripts(GlobalObject* globalObject, const Vector<Script>& scripts, const String& uncaughtExceptionName, bool alwaysDumpUncaughtException, bool dump, bool module)
 {
-    const char* script;
     String fileName;
     Vector<char> scriptBuffer;
 
@@ -637,52 +3367,65 @@ static bool runWithScripts(GlobalObject* globalObject, const Vector<Script>& scr
         JSC::Options::dumpGeneratedBytecodes() = true;
 
     VM& vm = globalObject->vm();
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+    bool success = true;
 
 #if ENABLE(SAMPLING_FLAGS)
     SamplingFlags::start();
 #endif
 
-    bool success = true;
     for (size_t i = 0; i < scripts.size(); i++) {
-        if (scripts[i].isFile) {
+        JSInternalPromise* promise = nullptr;
+        bool isModule = module || scripts[i].scriptType == Script::ScriptType::Module;
+        if (scripts[i].codeSource == Script::CodeSource::File) {
             fileName = scripts[i].argument;
-            if (!fillBufferWithContentsOfFile(fileName, scriptBuffer))
-                return false; // fail early so we can catch missing files
-            script = scriptBuffer.data();
+            if (scripts[i].strictMode == Script::StrictMode::Strict)
+                scriptBuffer.append("\"use strict\";\n", strlen("\"use strict\";\n"));
+
+            if (isModule)
+                promise = loadAndEvaluateModule(globalObject->globalExec(), fileName);
+            else {
+                if (!fetchScriptFromLocalFileSystem(fileName, scriptBuffer))
+                    return false; // fail early so we can catch missing files
+            }
         } else {
-            script = scripts[i].argument;
-            fileName = "[Command Line]";
+            size_t commandLineLength = strlen(scripts[i].argument);
+            scriptBuffer.resize(commandLineLength);
+            std::copy(scripts[i].argument, scripts[i].argument + commandLineLength, scriptBuffer.begin());
+            fileName = ASCIILiteral("[Command Line]");
         }
 
-        vm.startSampling();
+        bool isLastFile = i == scripts.size() - 1;
+        if (isModule) {
+            if (!promise)
+                promise = loadAndEvaluateModule(globalObject->globalExec(), makeSource(stringFromUTF(scriptBuffer), SourceOrigin { absolutePath(fileName) }, fileName, TextPosition(), SourceProviderSourceType::Module));
+            scope.clearException();
+
+            JSFunction* fulfillHandler = JSNativeStdFunction::create(vm, globalObject, 1, String(), [&, isLastFile](ExecState* exec) {
+                checkException(globalObject, isLastFile, false, exec->argument(0), uncaughtExceptionName, alwaysDumpUncaughtException, dump, success);
+                return JSValue::encode(jsUndefined());
+            });
 
-        JSValue evaluationException;
-        JSValue returnValue = evaluate(globalObject->globalExec(), jscSource(script, fileName), JSValue(), &evaluationException);
-        success = success && !evaluationException;
-        if (dump && !evaluationException)
-            printf("End: %s\n", returnValue.toString(globalObject->globalExec())->value(globalObject->globalExec()).utf8().data());
-        if (evaluationException) {
-            printf("Exception: %s\n", evaluationException.toString(globalObject->globalExec())->value(globalObject->globalExec()).utf8().data());
-            Identifier stackID(globalObject->globalExec(), "stack");
-            JSValue stackValue = evaluationException.get(globalObject->globalExec(), stackID);
-            if (!stackValue.isUndefinedOrNull())
-                printf("%s\n", stackValue.toString(globalObject->globalExec())->value(globalObject->globalExec()).utf8().data());
+            JSFunction* rejectHandler = JSNativeStdFunction::create(vm, globalObject, 1, String(), [&, isLastFile](ExecState* exec) {
+                checkException(globalObject, isLastFile, true, exec->argument(0), uncaughtExceptionName, alwaysDumpUncaughtException, dump, success);
+                return JSValue::encode(jsUndefined());
+            });
+
+            promise->then(globalObject->globalExec(), fulfillHandler, rejectHandler);
+            vm.drainMicrotasks();
+        } else {
+            NakedPtr<Exception> evaluationException;
+            JSValue returnValue = evaluate(globalObject->globalExec(), jscSource(scriptBuffer, SourceOrigin { absolutePath(fileName) }, fileName), JSValue(), evaluationException);
+            ASSERT(!scope.exception());
+            if (evaluationException)
+                returnValue = evaluationException->value();
+            checkException(globalObject, isLastFile, evaluationException, returnValue, uncaughtExceptionName, alwaysDumpUncaughtException, dump, success);
         }
 
-        vm.stopSampling();
-        globalObject->globalExec()->clearException();
+        scriptBuffer.clear();
+        scope.clearException();
     }
 
-#if ENABLE(SAMPLING_FLAGS)
-    SamplingFlags::stop();
-#endif
-#if ENABLE(SAMPLING_REGIONS)
-    SamplingRegion::dump();
-#endif
-    vm.dumpSampleData(globalObject->globalExec());
-#if ENABLE(SAMPLING_COUNTERS)
-    AbstractSamplingCounter::dump();
-#endif
 #if ENABLE(REGEXP_TRACING)
     vm.dumpRegExpTrace();
 #endif
@@ -693,7 +3436,13 @@ static bool runWithScripts(GlobalObject* globalObject, const Vector<Script>& scr
 
 static void runInteractive(GlobalObject* globalObject)
 {
-    String interpreterName("Interpreter");
+    VM& vm = globalObject->vm();
+    auto scope = DECLARE_CATCH_SCOPE(vm);
+
+    std::optional<DirectoryName> directoryName = currentWorkingDirectory();
+    if (!directoryName)
+        return;
+    SourceOrigin sourceOrigin(resolvePath(directoryName.value(), ModuleName("interpreter")));
     
     bool shouldQuit = false;
     while (!shouldQuit) {
@@ -708,20 +3457,23 @@ static void runInteractive(GlobalObject* globalObject)
                 break;
             source = source + line;
             source = source + '\n';
-            checkSyntax(globalObject->vm(), makeSource(source, interpreterName), error);
-            if (!line[0])
+            checkSyntax(globalObject->vm(), makeSource(source, sourceOrigin), error);
+            if (!line[0]) {
+                free(line);
                 break;
+            }
             add_history(line);
-        } while (error.m_syntaxErrorType == ParserError::SyntaxErrorRecoverable);
+            free(line);
+        } while (error.syntaxErrorType() == ParserError::SyntaxErrorRecoverable);
         
-        if (error.m_type != ParserError::ErrorNone) {
-            printf("%s:%d\n", error.m_message.utf8().data(), error.m_line);
+        if (error.isValid()) {
+            printf("%s:%d\n", error.message().utf8().data(), error.line());
             continue;
         }
         
         
-        JSValue evaluationException;
-        JSValue returnValue = evaluate(globalObject->globalExec(), makeSource(source, interpreterName), JSValue(), &evaluationException);
+        NakedPtr<Exception> evaluationException;
+        JSValue returnValue = evaluate(globalObject->globalExec(), makeSource(source, sourceOrigin), JSValue(), evaluationException);
 #else
         printf("%s", interactivePrompt);
         Vector<char, 256> line;
@@ -734,17 +3486,17 @@ static void runInteractive(GlobalObject* globalObject)
         }
         if (line.isEmpty())
             break;
-        line.append('\0');
 
-        JSValue evaluationException;
-        JSValue returnValue = evaluate(globalObject->globalExec(), jscSource(line.data(), interpreterName), JSValue(), &evaluationException);
+        NakedPtr<Exception> evaluationException;
+        JSValue returnValue = evaluate(globalObject->globalExec(), jscSource(line, sourceOrigin, sourceOrigin.string()), JSValue(), evaluationException);
 #endif
         if (evaluationException)
-            printf("Exception: %s\n", evaluationException.toString(globalObject->globalExec())->value(globalObject->globalExec()).utf8().data());
+            printf("Exception: %s\n", evaluationException->value().toWTFString(globalObject->globalExec()).utf8().data());
         else
-            printf("%s\n", returnValue.toString(globalObject->globalExec())->value(globalObject->globalExec()).utf8().data());
+            printf("%s\n", returnValue.toWTFString(globalObject->globalExec()).utf8().data());
 
-        globalObject->globalExec()->clearException();
+        scope.clearException();
+        globalObject->vm().drainMicrotasks();
     }
     printf("\n");
 }
@@ -757,38 +3509,48 @@ static NO_RETURN void printUsageStatement(bool help = false)
     fprintf(stderr, "  -f         Specifies a source file (deprecated)\n");
     fprintf(stderr, "  -h|--help  Prints this help message\n");
     fprintf(stderr, "  -i         Enables interactive mode (default if no files are specified)\n");
+    fprintf(stderr, "  -m         Execute as a module\n");
 #if HAVE(SIGNAL_H)
     fprintf(stderr, "  -s         Installs signal handlers that exit on a crash (Unix platforms only)\n");
 #endif
     fprintf(stderr, "  -p <file>  Outputs profiling data to a file\n");
     fprintf(stderr, "  -x         Output exit code before terminating\n");
     fprintf(stderr, "\n");
+    fprintf(stderr, "  --sample                   Collects and outputs sampling profiler data\n");
+    fprintf(stderr, "  --test262-async            Check that some script calls the print function with the string 'Test262:AsyncTestComplete'\n");
+    fprintf(stderr, "  --strict-file=<file>       Parse the given file as if it were in strict mode (this option may be passed more than once)\n");
+    fprintf(stderr, "  --module-file=<file>       Parse and evaluate the given file as module (this option may be passed more than once)\n");
+    fprintf(stderr, "  --exception=<name>         Check the last script exits with an uncaught exception with the specified name\n");
+    fprintf(stderr, "  --dumpException            Dump uncaught exception text\n");
     fprintf(stderr, "  --options                  Dumps all JSC VM options and exits\n");
-    fprintf(stderr, "  --dumpOptions              Dumps all JSC VM options before continuing\n");
+    fprintf(stderr, "  --dumpOptions              Dumps all non-default JSC VM options before continuing\n");
     fprintf(stderr, "  --<jsc VM option>=<value>  Sets the specified JSC VM option\n");
     fprintf(stderr, "\n");
 
-    exit(help ? EXIT_SUCCESS : EXIT_FAILURE);
+    jscExit(help ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 void CommandLine::parseArguments(int argc, char** argv)
 {
+    Options::initialize();
+    
     int i = 1;
-    bool needToDumpOptions = false;
+    JSC::Options::DumpLevel dumpOptionsLevel = JSC::Options::DumpLevel::None;
     bool needToExit = false;
 
+    bool hasBadJSCOptions = false;
     for (; i < argc; ++i) {
         const char* arg = argv[i];
         if (!strcmp(arg, "-f")) {
             if (++i == argc)
                 printUsageStatement();
-            m_scripts.append(Script(true, argv[i]));
+            m_scripts.append(Script(Script::StrictMode::Sloppy, Script::CodeSource::File, Script::ScriptType::Script, argv[i]));
             continue;
         }
         if (!strcmp(arg, "-e")) {
             if (++i == argc)
                 printUsageStatement();
-            m_scripts.append(Script(false, argv[i]));
+            m_scripts.append(Script(Script::StrictMode::Sloppy, Script::CodeSource::CommandLine, Script::ScriptType::Script, argv[i]));
             continue;
         }
         if (!strcmp(arg, "-i")) {
@@ -806,6 +3568,10 @@ void CommandLine::parseArguments(int argc, char** argv)
             m_profilerOutput = argv[i];
             continue;
         }
+        if (!strcmp(arg, "-m")) {
+            m_module = true;
+            continue;
+        }
         if (!strcmp(arg, "-s")) {
 #if HAVE(SIGNAL_H)
             signal(SIGILL, _exit);
@@ -827,96 +3593,195 @@ void CommandLine::parseArguments(int argc, char** argv)
             printUsageStatement(true);
 
         if (!strcmp(arg, "--options")) {
-            needToDumpOptions = true;
+            dumpOptionsLevel = JSC::Options::DumpLevel::Verbose;
             needToExit = true;
             continue;
         }
         if (!strcmp(arg, "--dumpOptions")) {
-            needToDumpOptions = true;
+            dumpOptionsLevel = JSC::Options::DumpLevel::Overridden;
+            continue;
+        }
+        if (!strcmp(arg, "--sample")) {
+            JSC::Options::useSamplingProfiler() = true;
+            JSC::Options::collectSamplingProfilerDataForJSCShell() = true;
+            m_dumpSamplingProfilerData = true;
+            continue;
+        }
+
+        static const char* timeoutMultiplierOptStr = "--timeoutMultiplier=";
+        static const unsigned timeoutMultiplierOptStrLength = strlen(timeoutMultiplierOptStr);
+        if (!strncmp(arg, timeoutMultiplierOptStr, timeoutMultiplierOptStrLength)) {
+            const char* valueStr = &arg[timeoutMultiplierOptStrLength];
+            if (sscanf(valueStr, "%lf", &s_timeoutMultiplier) != 1)
+                dataLog("WARNING: --timeoutMultiplier=", valueStr, " is invalid. Expects a numeric ratio.\n");
+            continue;
+        }
+
+        if (!strcmp(arg, "--test262-async")) {
+            test262AsyncTest = true;
+            continue;
+        }
+
+        if (!strcmp(arg, "--remote-debug")) {
+            m_enableRemoteDebugging = true;
+            continue;
+        }
+
+        static const unsigned strictFileStrLength = strlen("--strict-file=");
+        if (!strncmp(arg, "--strict-file=", strictFileStrLength)) {
+            m_scripts.append(Script(Script::StrictMode::Strict, Script::CodeSource::File, Script::ScriptType::Script, argv[i] + strictFileStrLength));
+            continue;
+        }
+
+        static const unsigned moduleFileStrLength = strlen("--module-file=");
+        if (!strncmp(arg, "--module-file=", moduleFileStrLength)) {
+            m_scripts.append(Script(Script::StrictMode::Sloppy, Script::CodeSource::File, Script::ScriptType::Module, argv[i] + moduleFileStrLength));
+            continue;
+        }
+
+        if (!strcmp(arg, "--dumpException")) {
+            m_alwaysDumpUncaughtException = true;
+            continue;
+        }
+
+        static const unsigned exceptionStrLength = strlen("--exception=");
+        if (!strncmp(arg, "--exception=", exceptionStrLength)) {
+            m_uncaughtExceptionName = String(arg + exceptionStrLength);
             continue;
         }
 
         // See if the -- option is a JSC VM option.
-        // NOTE: At this point, we know that the arg starts with "--". Skip it.
-        if (JSC::Options::setOption(&arg[2])) {
-            // The arg was recognized as a VM option and has been parsed.
-            continue; // Just continue with the next arg. 
+        if (strstr(arg, "--") == arg) {
+            if (!JSC::Options::setOption(&arg[2])) {
+                hasBadJSCOptions = true;
+                dataLog("ERROR: invalid option: ", arg, "\n");
+            }
+            continue;
         }
 
         // This arg is not recognized by the VM nor by jsc. Pass it on to the
         // script.
-        m_scripts.append(Script(true, argv[i]));
+        m_scripts.append(Script(Script::StrictMode::Sloppy, Script::CodeSource::File, Script::ScriptType::Script, argv[i]));
     }
 
+    if (hasBadJSCOptions && JSC::Options::validateOptions())
+        CRASH();
+
     if (m_scripts.isEmpty())
         m_interactive = true;
 
     for (; i < argc; ++i)
         m_arguments.append(argv[i]);
 
-    if (needToDumpOptions)
-        JSC::Options::dumpAllOptions(stderr);
+    if (dumpOptionsLevel != JSC::Options::DumpLevel::None) {
+        const char* optionsTitle = (dumpOptionsLevel == JSC::Options::DumpLevel::Overridden)
+            ? "Modified JSC runtime options:"
+            : "All JSC runtime options:";
+        JSC::Options::dumpAllOptions(stderr, dumpOptionsLevel, optionsTitle);
+    }
+    JSC::Options::ensureOptionsAreCoherent();
     if (needToExit)
-        exit(EXIT_SUCCESS);
+        jscExit(EXIT_SUCCESS);
 }
 
-int jscmain(int argc, char** argv)
+template<typename Func>
+int runJSC(CommandLine options, const Func& func)
 {
-    // Note that the options parsing can affect VM creation, and thus
-    // comes first.
-    CommandLine options(argc, argv);
-    VM* vm = VM::create(LargeHeap).leakRef();
+    Worker worker(Workers::singleton());
+    
+    VM& vm = VM::create(LargeHeap).leakRef();
+    JSLockHolder locker(&vm);
+
     int result;
-    {
-        APIEntryShim shim(vm);
+    if (options.m_profile && !vm.m_perBytecodeProfiler)
+        vm.m_perBytecodeProfiler = std::make_unique<Profiler::Database>(vm);
 
-        if (options.m_profile && !vm->m_perBytecodeProfiler)
-            vm->m_perBytecodeProfiler = adoptPtr(new Profiler::Database(*vm));
-    
-        GlobalObject* globalObject = GlobalObject::create(*vm, GlobalObject::createStructure(*vm, jsNull()), options.m_arguments);
-        bool success = runWithScripts(globalObject, options.m_scripts, options.m_dump);
-        if (options.m_interactive && success)
-            runInteractive(globalObject);
+    GlobalObject* globalObject = GlobalObject::create(vm, GlobalObject::createStructure(vm, jsNull()), options.m_arguments);
+    globalObject->setRemoteDebuggingEnabled(options.m_enableRemoteDebugging);
+    bool success = func(vm, globalObject);
+    if (options.m_interactive && success)
+        runInteractive(globalObject);
 
-        result = success ? 0 : 3;
+    vm.drainMicrotasks();
+    result = success && (test262AsyncTest == test262AsyncPassed) ? 0 : 3;
 
-        if (options.m_exitCode)
-            printf("jsc exiting %d\n", result);
-    
-        if (options.m_profile) {
-            if (!vm->m_perBytecodeProfiler->save(options.m_profilerOutput.utf8().data()))
-                fprintf(stderr, "could not save profiler output.\n");
-        }
+    if (options.m_exitCode)
+        printf("jsc exiting %d\n", result);
+
+    if (options.m_profile) {
+        if (!vm.m_perBytecodeProfiler->save(options.m_profilerOutput.utf8().data()))
+            fprintf(stderr, "could not save profiler output.\n");
     }
-    
+
+#if ENABLE(JIT)
+    if (Options::useExceptionFuzz())
+        printf("JSC EXCEPTION FUZZ: encountered %u checks.\n", numberOfExceptionFuzzChecks());
+    bool fireAtEnabled =
+    Options::fireExecutableAllocationFuzzAt() || Options::fireExecutableAllocationFuzzAtOrAfter();
+    if (Options::useExecutableAllocationFuzz() && (!fireAtEnabled || Options::verboseExecutableAllocationFuzz()))
+        printf("JSC EXECUTABLE ALLOCATION FUZZ: encountered %u checks.\n", numberOfExecutableAllocationFuzzChecks());
+    if (Options::useOSRExitFuzz()) {
+        printf("JSC OSR EXIT FUZZ: encountered %u static checks.\n", numberOfStaticOSRExitFuzzChecks());
+        printf("JSC OSR EXIT FUZZ: encountered %u dynamic checks.\n", numberOfOSRExitFuzzChecks());
+    }
+
+    auto compileTimeStats = JIT::compileTimeStats();
+    Vector<CString> compileTimeKeys;
+    for (auto& entry : compileTimeStats)
+        compileTimeKeys.append(entry.key);
+    std::sort(compileTimeKeys.begin(), compileTimeKeys.end());
+    for (CString key : compileTimeKeys)
+        printf("%40s: %.3lf ms\n", key.data(), compileTimeStats.get(key));
+#endif
+
+    if (Options::gcAtEnd()) {
+        // We need to hold the API lock to do a GC.
+        JSLockHolder locker(&vm);
+        vm.heap.collectAllGarbage();
+    }
+
+    if (options.m_dumpSamplingProfilerData) {
+#if ENABLE(SAMPLING_PROFILER)
+        JSLockHolder locker(&vm);
+        vm.samplingProfiler()->reportTopFunctions();
+        vm.samplingProfiler()->reportTopBytecodes();
+#else
+        dataLog("Sampling profiler is not enabled on this platform\n");
+#endif
+    }
+
     return result;
 }
 
-static bool fillBufferWithContentsOfFile(const String& fileName, Vector<char>& buffer)
+int jscmain(int argc, char** argv)
 {
-    FILE* f = fopen(fileName.utf8().data(), "r");
-    if (!f) {
-        fprintf(stderr, "Could not open file: %s\n", fileName.utf8().data());
-        return false;
-    }
+    // Need to override and enable restricted options before we start parsing options below.
+    Options::enableRestrictedOptions(true);
+
+    // Note that the options parsing can affect VM creation, and thus
+    // comes first.
+    CommandLine options(argc, argv);
 
-    size_t bufferSize = 0;
-    size_t bufferCapacity = 1024;
+    // Initialize JSC before getting VM.
+    WTF::initializeMainThread();
+    JSC::initializeThreading();
+    startTimeoutThreadIfNeeded();
 
-    buffer.resize(bufferCapacity);
+    int result;
+    result = runJSC(
+        options,
+        [&] (VM&, GlobalObject* globalObject) {
+            return runWithScripts(globalObject, options.m_scripts, options.m_uncaughtExceptionName, options.m_alwaysDumpUncaughtException, options.m_dump, options.m_module);
+        });
 
-    while (!feof(f) && !ferror(f)) {
-        bufferSize += fread(buffer.data() + bufferSize, 1, bufferCapacity - bufferSize, f);
-        if (bufferSize == bufferCapacity) { // guarantees space for trailing '\0'
-            bufferCapacity *= 2;
-            buffer.resize(bufferCapacity);
-        }
-    }
-    fclose(f);
-    buffer[bufferSize] = '\0';
+    printSuperSamplerState();
 
-    if (buffer[0] == '#' && buffer[1] == '!')
-        buffer[0] = buffer[1] = '/';
+    return result;
+}
 
-    return true;
+#if OS(WINDOWS)
+extern "C" __declspec(dllexport) int WINAPI dllLauncherEntryPoint(int argc, const char* argv[])
+{
+    return main(argc, const_cast<char**>(argv));
 }
+#endif
-- 
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