webkitgtk-2.4.11webkitgtk-2.4.11

1 files changed, 306 insertions, 440 deletions

diff --git a/Source/JavaScriptCore/interpreter/Interpreter.cpp b/Source/JavaScriptCore/interpreter/Interpreter.cpp
index 18a90760d..4fbc8229a 100644
--- a/Source/JavaScriptCore/interpreter/Interpreter.cpp
+++ b/Source/JavaScriptCore/interpreter/Interpreter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008, 2009, 2010, 2012-2015 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -11,7 +11,7 @@
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
- * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  *     its contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission.
  *
@@ -30,25 +30,25 @@
 #include "config.h"
 #include "Interpreter.h"
 
+#include "Arguments.h"
 #include "BatchedTransitionOptimizer.h"
+#include "CallFrame.h"
 #include "CallFrameClosure.h"
-#include "ClonedArguments.h"
+#include "CallFrameInlines.h"
 #include "CodeBlock.h"
-#include "DirectArguments.h"
 #include "Heap.h"
 #include "Debugger.h"
 #include "DebuggerCallFrame.h"
 #include "ErrorInstance.h"
 #include "EvalCodeCache.h"
-#include "Exception.h"
 #include "ExceptionHelpers.h"
 #include "GetterSetter.h"
+#include "JSActivation.h"
 #include "JSArray.h"
 #include "JSBoundFunction.h"
-#include "JSCInlines.h"
-#include "JSLexicalEnvironment.h"
-#include "JSModuleEnvironment.h"
+#include "JSNameScope.h"
 #include "JSNotAnObject.h"
+#include "JSPropertyNameIterator.h"
 #include "JSStackInlines.h"
 #include "JSString.h"
 #include "JSWithScope.h"
@@ -56,27 +56,24 @@
 #include "LLIntThunks.h"
 #include "LegacyProfiler.h"
 #include "LiteralParser.h"
+#include "NameInstance.h"
 #include "ObjectPrototype.h"
+#include "Operations.h"
 #include "Parser.h"
 #include "ProtoCallFrame.h"
 #include "RegExpObject.h"
 #include "RegExpPrototype.h"
 #include "Register.h"
 #include "SamplingTool.h"
-#include "ScopedArguments.h"
-#include "StackAlignment.h"
 #include "StackVisitor.h"
 #include "StrictEvalActivation.h"
 #include "StrongInlines.h"
-#include "Symbol.h"
 #include "VMEntryScope.h"
-#include "VMInlines.h"
 #include "VirtualRegister.h"
 
 #include <limits.h>
 #include <stdio.h>
 #include <wtf/StackStats.h>
-#include <wtf/StdLibExtras.h>
 #include <wtf/StringPrintStream.h>
 #include <wtf/Threading.h>
 #include <wtf/WTFThreadData.h>
@@ -86,53 +83,26 @@
 #include "JIT.h"
 #endif
 
+#define WTF_USE_GCC_COMPUTED_GOTO_WORKAROUND (ENABLE(LLINT) && !defined(__llvm__))
+
 using namespace std;
 
 namespace JSC {
 
-String StackFrame::friendlySourceURL() const
+Interpreter::ErrorHandlingMode::ErrorHandlingMode(ExecState *exec)
+    : m_interpreter(*exec->interpreter())
 {
-    String traceLine;
-    
-    switch (codeType) {
-    case StackFrameEvalCode:
-    case StackFrameModuleCode:
-    case StackFrameFunctionCode:
-    case StackFrameGlobalCode:
-        if (!sourceURL.isEmpty())
-            traceLine = sourceURL.impl();
-        break;
-    case StackFrameNativeCode:
-        traceLine = "[native code]";
-        break;
-    }
-    return traceLine.isNull() ? emptyString() : traceLine;
+    if (!m_interpreter.m_errorHandlingModeReentry)
+        m_interpreter.stack().enableErrorStackReserve();
+    m_interpreter.m_errorHandlingModeReentry++;
 }
 
-String StackFrame::friendlyFunctionName(CallFrame* callFrame) const
+Interpreter::ErrorHandlingMode::~ErrorHandlingMode()
 {
-    String traceLine;
-    JSObject* stackFrameCallee = callee.get();
-
-    switch (codeType) {
-    case StackFrameEvalCode:
-        traceLine = "eval code";
-        break;
-    case StackFrameModuleCode:
-        traceLine = "module code";
-        break;
-    case StackFrameNativeCode:
-        if (callee)
-            traceLine = getCalculatedDisplayName(callFrame, stackFrameCallee).impl();
-        break;
-    case StackFrameFunctionCode:
-        traceLine = getCalculatedDisplayName(callFrame, stackFrameCallee).impl();
-        break;
-    case StackFrameGlobalCode:
-        traceLine = "global code";
-        break;
-    }
-    return traceLine.isNull() ? emptyString() : traceLine;
+    m_interpreter.m_errorHandlingModeReentry--;
+    ASSERT(m_interpreter.m_errorHandlingModeReentry >= 0);
+    if (!m_interpreter.m_errorHandlingModeReentry)
+        m_interpreter.stack().disableErrorStackReserve();
 }
 
 JSValue eval(CallFrame* callFrame)
@@ -143,27 +113,21 @@ JSValue eval(CallFrame* callFrame)
     JSValue program = callFrame->argument(0);
     if (!program.isString())
         return program;
-
+    
     TopCallFrameSetter topCallFrame(callFrame->vm(), callFrame);
-    JSGlobalObject* globalObject = callFrame->lexicalGlobalObject();
-    if (!globalObject->evalEnabled()) {
-        callFrame->vm().throwException(callFrame, createEvalError(callFrame, globalObject->evalDisabledErrorMessage()));
-        return jsUndefined();
-    }
     String programSource = asString(program)->value(callFrame);
     if (callFrame->hadException())
         return JSValue();
     
     CallFrame* callerFrame = callFrame->callerFrame();
     CodeBlock* callerCodeBlock = callerFrame->codeBlock();
-    JSScope* callerScopeChain = callerFrame->uncheckedR(callerCodeBlock->scopeRegister().offset()).Register::scope();
-    UnlinkedCodeBlock* callerUnlinkedCodeBlock = callerCodeBlock->unlinkedCodeBlock();
-
-    bool isArrowFunctionContext = callerUnlinkedCodeBlock->isArrowFunction() || callerUnlinkedCodeBlock->isArrowFunctionContext();
-    EvalExecutable* eval = callerCodeBlock->evalCodeCache().tryGet(callerCodeBlock->isStrictMode(), programSource, isArrowFunctionContext, callerScopeChain);
+    JSScope* callerScopeChain = callerFrame->scope();
+    EvalExecutable* eval = callerCodeBlock->evalCodeCache().tryGet(callerCodeBlock->isStrictMode(), programSource, callerScopeChain);
 
     if (!eval) {
         if (!callerCodeBlock->isStrictMode()) {
+            // FIXME: We can use the preparser in strict mode, we just need additional logic
+            // to prevent duplicates.
             if (programSource.is8Bit()) {
                 LiteralParser<LChar> preparser(callFrame, programSource.characters8(), programSource.length(), NonStrictJSON);
                 if (JSValue parsedObject = preparser.tryLiteralParse())
@@ -178,11 +142,7 @@ JSValue eval(CallFrame* callFrame)
         // If the literal parser bailed, it should not have thrown exceptions.
         ASSERT(!callFrame->vm().exception());
 
-        ThisTDZMode thisTDZMode = ThisTDZMode::CheckIfNeeded;
-        if (callerUnlinkedCodeBlock->constructorKind() == ConstructorKind::Derived)
-            thisTDZMode = ThisTDZMode::AlwaysCheck;
-
-        eval = callerCodeBlock->evalCodeCache().getSlow(callFrame, callerCodeBlock, callerCodeBlock->isStrictMode(), thisTDZMode, callerCodeBlock->unlinkedCodeBlock()->derivedContextType(), callerCodeBlock->unlinkedCodeBlock()->isArrowFunction(), programSource, callerScopeChain);
+        eval = callerCodeBlock->evalCodeCache().getSlow(callFrame, callerCodeBlock->ownerExecutable(), callerCodeBlock->isStrictMode(), programSource, callerScopeChain);
         if (!eval)
             return jsUndefined();
     }
@@ -192,103 +152,109 @@ JSValue eval(CallFrame* callFrame)
     return interpreter->execute(eval, callFrame, thisValue, callerScopeChain);
 }
 
-unsigned sizeOfVarargs(CallFrame* callFrame, JSValue arguments, uint32_t firstVarArgOffset)
+CallFrame* sizeAndAllocFrameForVarargs(CallFrame* callFrame, JSStack* stack, JSValue arguments, int firstFreeRegister)
 {
-    if (UNLIKELY(!arguments.isCell())) {
-        if (arguments.isUndefinedOrNull())
+    if (!arguments) { // f.apply(x, arguments), with arguments unmodified.
+        unsigned argumentCountIncludingThis = callFrame->argumentCountIncludingThis();
+        CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + firstFreeRegister - argumentCountIncludingThis - JSStack::CallFrameHeaderSize - 1);
+        if (argumentCountIncludingThis > Arguments::MaxArguments + 1 || !stack->grow(newCallFrame->registers())) {
+            callFrame->vm().throwException(callFrame, createStackOverflowError(callFrame));
             return 0;
-        
-        callFrame->vm().throwException(callFrame, createInvalidFunctionApplyParameterError(callFrame, arguments));
-        return 0;
+        }
+        return newCallFrame;
     }
-    
-    JSCell* cell = arguments.asCell();
-    unsigned length;
-    switch (cell->type()) {
-    case DirectArgumentsType:
-        length = jsCast<DirectArguments*>(cell)->length(callFrame);
-        break;
-    case ScopedArgumentsType:
-        length =jsCast<ScopedArguments*>(cell)->length(callFrame);
-        break;
-    case StringType:
-        callFrame->vm().throwException(callFrame, createInvalidFunctionApplyParameterError(callFrame,  arguments));
+
+    if (arguments.isUndefinedOrNull()) {
+        CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + firstFreeRegister - 1 - JSStack::CallFrameHeaderSize - 1);
+        if (!stack->grow(newCallFrame->registers())) {
+            callFrame->vm().throwException(callFrame, createStackOverflowError(callFrame));
+            return 0;
+        }
+        return newCallFrame;
+    }
+
+    if (!arguments.isObject()) {
+        callFrame->vm().throwException(callFrame, createInvalidParameterError(callFrame, "Function.prototype.apply", arguments));
         return 0;
-    default:
-        ASSERT(arguments.isObject());
-        if (isJSArray(cell))
-            length = jsCast<JSArray*>(cell)->length();
-        else
-            length = jsCast<JSObject*>(cell)->get(callFrame, callFrame->propertyNames().length).toUInt32(callFrame);
-        break;
     }
-    
-    if (length >= firstVarArgOffset)
-        length -= firstVarArgOffset;
-    else
-        length = 0;
-    
-    return length;
-}
 
-unsigned sizeFrameForVarargs(CallFrame* callFrame, JSStack* stack, JSValue arguments, unsigned numUsedStackSlots, uint32_t firstVarArgOffset)
-{
-    unsigned length = sizeOfVarargs(callFrame, arguments, firstVarArgOffset);
-    
-    CallFrame* calleeFrame = calleeFrameForVarargs(callFrame, numUsedStackSlots, length + 1);
-    if (length > maxArguments || !stack->ensureCapacityFor(calleeFrame->registers())) {
-        throwStackOverflowError(callFrame);
+    if (asObject(arguments)->classInfo() == Arguments::info()) {
+        Arguments* argsObject = asArguments(arguments);
+        unsigned argCount = argsObject->length(callFrame);
+        CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + firstFreeRegister - CallFrame::offsetFor(argCount + 1));
+        if (argCount > Arguments::MaxArguments || !stack->grow(newCallFrame->registers())) {
+            callFrame->vm().throwException(callFrame, createStackOverflowError(callFrame));
+            return 0;
+        }
+        return newCallFrame;
+    }
+
+    if (isJSArray(arguments)) {
+        JSArray* array = asArray(arguments);
+        unsigned argCount = array->length();
+        CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + firstFreeRegister - CallFrame::offsetFor(argCount + 1));
+        if (argCount > Arguments::MaxArguments || !stack->grow(newCallFrame->registers())) {
+            callFrame->vm().throwException(callFrame, createStackOverflowError(callFrame));
+            return 0;
+        }
+        return newCallFrame;
+    }
+
+    JSObject* argObject = asObject(arguments);
+    unsigned argCount = argObject->get(callFrame, callFrame->propertyNames().length).toUInt32(callFrame);
+    CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + firstFreeRegister - CallFrame::offsetFor(argCount + 1));
+    if (argCount > Arguments::MaxArguments || !stack->grow(newCallFrame->registers())) {
+        callFrame->vm().throwException(callFrame,  createStackOverflowError(callFrame));
         return 0;
     }
-    
-    return length;
+    return newCallFrame;
 }
 
-void loadVarargs(CallFrame* callFrame, VirtualRegister firstElementDest, JSValue arguments, uint32_t offset, uint32_t length)
+void loadVarargs(CallFrame* callFrame, CallFrame* newCallFrame, JSValue thisValue, JSValue arguments)
 {
-    if (UNLIKELY(!arguments.isCell()) || !length)
+    if (!arguments) { // f.apply(x, arguments), with arguments unmodified.
+        unsigned argumentCountIncludingThis = callFrame->argumentCountIncludingThis();
+
+        newCallFrame->setArgumentCountIncludingThis(argumentCountIncludingThis);
+        newCallFrame->setThisValue(thisValue);
+        for (size_t i = 0; i < callFrame->argumentCount(); ++i)
+            newCallFrame->setArgument(i, callFrame->argumentAfterCapture(i));
         return;
+    }
     
-    JSCell* cell = arguments.asCell();
-    switch (cell->type()) {
-    case DirectArgumentsType:
-        jsCast<DirectArguments*>(cell)->copyToArguments(callFrame, firstElementDest, offset, length);
-        return;
-    case ScopedArgumentsType:
-        jsCast<ScopedArguments*>(cell)->copyToArguments(callFrame, firstElementDest, offset, length);
+    if (arguments.isUndefinedOrNull()) {
+        newCallFrame->setArgumentCountIncludingThis(1);
+        newCallFrame->setThisValue(thisValue);
         return;
-    default: {
-        ASSERT(arguments.isObject());
-        JSObject* object = jsCast<JSObject*>(cell);
-        if (isJSArray(object)) {
-            jsCast<JSArray*>(object)->copyToArguments(callFrame, firstElementDest, offset, length);
-            return;
-        }
-        unsigned i;
-        for (i = 0; i < length && object->canGetIndexQuickly(i + offset); ++i)
-            callFrame->r(firstElementDest + i) = object->getIndexQuickly(i + offset);
-        for (; i < length; ++i)
-            callFrame->r(firstElementDest + i) = object->get(callFrame, i + offset);
+    }
+    
+    if (asObject(arguments)->classInfo() == Arguments::info()) {
+        Arguments* argsObject = asArguments(arguments);
+        unsigned argCount = argsObject->length(callFrame);
+        newCallFrame->setArgumentCountIncludingThis(argCount + 1);
+        newCallFrame->setThisValue(thisValue);
+        argsObject->copyToArguments(callFrame, newCallFrame, argCount);
         return;
-    } }
-}
-
-void setupVarargsFrame(CallFrame* callFrame, CallFrame* newCallFrame, JSValue arguments, uint32_t offset, uint32_t length)
-{
-    VirtualRegister calleeFrameOffset(newCallFrame - callFrame);
+    }
     
-    loadVarargs(
-        callFrame,
-        calleeFrameOffset + CallFrame::argumentOffset(0),
-        arguments, offset, length);
+    if (isJSArray(arguments)) {
+        JSArray* array = asArray(arguments);
+        unsigned argCount = array->length();
+        newCallFrame->setArgumentCountIncludingThis(argCount + 1);
+        newCallFrame->setThisValue(thisValue);
+        array->copyToArguments(callFrame, newCallFrame, argCount);
+        return;
+    }
     
-    newCallFrame->setArgumentCountIncludingThis(length + 1);
-}
-
-void setupVarargsFrameAndSetThis(CallFrame* callFrame, CallFrame* newCallFrame, JSValue thisValue, JSValue arguments, uint32_t firstVarArgOffset, uint32_t length)
-{
-    setupVarargsFrame(callFrame, newCallFrame, arguments, firstVarArgOffset, length);
+    JSObject* argObject = asObject(arguments);
+    unsigned argCount = argObject->get(callFrame, callFrame->propertyNames().length).toUInt32(callFrame);
+    newCallFrame->setArgumentCountIncludingThis(argCount + 1);
     newCallFrame->setThisValue(thisValue);
+    for (size_t i = 0; i < argCount; ++i) {
+        newCallFrame->setArgument(i, asObject(arguments)->get(callFrame, i));
+        if (UNLIKELY(callFrame->vm().exception()))
+            return;
+    }
 }
 
 Interpreter::Interpreter(VM& vm)
@@ -306,9 +272,11 @@ Interpreter::~Interpreter()
 {
 }
 
-void Interpreter::initialize()
+void Interpreter::initialize(bool canUseJIT)
 {
-#if ENABLE(COMPUTED_GOTO_OPCODES)
+    UNUSED_PARAM(canUseJIT);
+
+#if ENABLE(COMPUTED_GOTO_OPCODES) && ENABLE(LLINT)
     m_opcodeTable = LLInt::opcodeMap();
     for (int i = 0; i < numOpcodeIDs; ++i)
         m_opcodeIDTable.add(m_opcodeTable[i], static_cast<OpcodeID>(i));
@@ -393,7 +361,7 @@ void Interpreter::dumpRegisters(CallFrame* callFrame)
     --it;
     dataLogF("[Callee]                   | %10p | %p \n", it, callFrame->callee());
     --it;
-    // FIXME: Remove the next decrement when the ScopeChain slot is removed from the call header
+    dataLogF("[ScopeChain]               | %10p | %p \n", it, callFrame->scope());
     --it;
 #if ENABLE(JIT)
     AbstractPC pc = callFrame->abstractReturnPC(callFrame->vm());
@@ -420,7 +388,7 @@ void Interpreter::dumpRegisters(CallFrame* callFrame)
     }
     dataLogF("-----------------------------------------------------------------------------\n");
 
-    end = it - codeBlock->m_numCalleeLocals + codeBlock->m_numVars;
+    end = it - codeBlock->m_numCalleeRegisters + codeBlock->m_numVars;
     if (it != end) {
         do {
             JSValue v = (*it).jsValue();
@@ -437,21 +405,68 @@ void Interpreter::dumpRegisters(CallFrame* callFrame)
 bool Interpreter::isOpcode(Opcode opcode)
 {
 #if ENABLE(COMPUTED_GOTO_OPCODES)
+#if !ENABLE(LLINT)
+    return static_cast<OpcodeID>(bitwise_cast<uintptr_t>(opcode)) <= op_end;
+#else
     return opcode != HashTraits<Opcode>::emptyValue()
         && !HashTraits<Opcode>::isDeletedValue(opcode)
         && m_opcodeIDTable.contains(opcode);
+#endif
 #else
     return opcode >= 0 && opcode <= op_end;
 #endif
 }
 
+static bool unwindCallFrame(StackVisitor& visitor)
+{
+    CallFrame* callFrame = visitor->callFrame();
+    CodeBlock* codeBlock = visitor->codeBlock();
+    CodeBlock* oldCodeBlock = codeBlock;
+    JSScope* scope = callFrame->scope();
+
+    if (Debugger* debugger = callFrame->vmEntryGlobalObject()->debugger()) {
+        if (callFrame->callee())
+            debugger->returnEvent(callFrame);
+        else
+            debugger->didExecuteProgram(callFrame);
+    }
+
+    JSValue activation;
+    if (oldCodeBlock->codeType() == FunctionCode && oldCodeBlock->needsActivation()) {
+#if ENABLE(DFG_JIT)
+        RELEASE_ASSERT(!visitor->isInlinedFrame());
+#endif
+        activation = callFrame->uncheckedR(oldCodeBlock->activationRegister().offset()).jsValue();
+        if (activation)
+            jsCast<JSActivation*>(activation)->tearOff(*scope->vm());
+    }
+
+    if (oldCodeBlock->codeType() == FunctionCode && oldCodeBlock->usesArguments()) {
+        if (Arguments* arguments = visitor->existingArguments()) {
+            if (activation)
+                arguments->didTearOffActivation(callFrame, jsCast<JSActivation*>(activation));
+#if ENABLE(DFG_JIT)
+            else if (visitor->isInlinedFrame())
+                arguments->tearOff(callFrame, visitor->inlineCallFrame());
+#endif
+            else
+                arguments->tearOff(callFrame);
+        }
+    }
+
+    CallFrame* callerFrame = callFrame->callerFrame();
+    if (callerFrame->isVMEntrySentinel()) {
+        callFrame->vm().topCallFrame = callerFrame->vmEntrySentinelCallerFrame();
+        return false;
+    }
+    return true;
+}
+
 static StackFrameCodeType getStackFrameCodeType(StackVisitor& visitor)
 {
     switch (visitor->codeType()) {
     case StackVisitor::Frame::Eval:
         return StackFrameEvalCode;
-    case StackVisitor::Frame::Module:
-        return StackFrameModuleCode;
     case StackVisitor::Frame::Function:
         return StackFrameFunctionCode;
     case StackVisitor::Frame::Global:
@@ -481,9 +496,6 @@ void StackFrame::computeLineAndColumn(unsigned& line, unsigned& column)
 
     line = divotLine + lineOffset;
     column = divotColumn + (divotLine ? 1 : firstLineColumnOffset);
-
-    if (executable->hasOverrideLineNumber())
-        line = executable->overrideLineNumber();
 }
 
 void StackFrame::expressionInfo(int& divot, int& startOffset, int& endOffset, unsigned& line, unsigned& column)
@@ -516,16 +528,6 @@ String StackFrame::toString(CallFrame* callFrame)
     return traceBuild.toString().impl();
 }
 
-static inline bool isWebAssemblyExecutable(ExecutableBase* executable)
-{
-#if !ENABLE(WEBASSEMBLY)
-    UNUSED_PARAM(executable);
-    return false;
-#else
-    return executable->isWebAssemblyExecutable();
-#endif
-}
-
 class GetStackTraceFunctor {
 public:
     GetStackTraceFunctor(VM& vm, Vector<StackFrame>& results, size_t remainingCapacity)
@@ -539,17 +541,15 @@ public:
     {
         VM& vm = m_vm;
         if (m_remainingCapacityForFrameCapture) {
-            if (visitor->isJSFrame()
-                && !isWebAssemblyExecutable(visitor->codeBlock()->ownerExecutable())
-                && !visitor->codeBlock()->unlinkedCodeBlock()->isBuiltinFunction()) {
+            if (visitor->isJSFrame()) {
                 CodeBlock* codeBlock = visitor->codeBlock();
                 StackFrame s = {
                     Strong<JSObject>(vm, visitor->callee()),
                     getStackFrameCodeType(visitor),
-                    Strong<ScriptExecutable>(vm, codeBlock->ownerScriptExecutable()),
+                    Strong<ExecutableBase>(vm, codeBlock->ownerExecutable()),
                     Strong<UnlinkedCodeBlock>(vm, codeBlock->unlinkedCodeBlock()),
                     codeBlock->source(),
-                    codeBlock->ownerScriptExecutable()->firstLine(),
+                    codeBlock->ownerExecutable()->lineNo(),
                     codeBlock->firstLineColumnOffset(),
                     codeBlock->sourceOffset(),
                     visitor->bytecodeOffset(),
@@ -557,7 +557,7 @@ public:
                 };
                 m_results.append(s);
             } else {
-                StackFrame s = { Strong<JSObject>(vm, visitor->callee()), StackFrameNativeCode, Strong<ScriptExecutable>(), Strong<UnlinkedCodeBlock>(), 0, 0, 0, 0, 0, String()};
+                StackFrame s = { Strong<JSObject>(vm, visitor->callee()), StackFrameNativeCode, Strong<ExecutableBase>(), Strong<UnlinkedCodeBlock>(), 0, 0, 0, 0, 0, String()};
                 m_results.append(s);
             }
     
@@ -576,6 +576,7 @@ private:
 void Interpreter::getStackTrace(Vector<StackFrame>& results, size_t maxStackSize)
 {
     VM& vm = m_vm;
+    ASSERT(!vm.topCallFrame->isVMEntrySentinel());
     CallFrame* callFrame = vm.topCallFrame;
     if (!callFrame)
         return;
@@ -596,26 +597,9 @@ JSString* Interpreter::stackTraceAsString(ExecState* exec, Vector<StackFrame> st
     return jsString(&exec->vm(), builder.toString());
 }
 
-ALWAYS_INLINE static HandlerInfo* findExceptionHandler(StackVisitor& visitor, CodeBlock* codeBlock, CodeBlock::RequiredHandler requiredHandler)
-{
-    ASSERT(codeBlock);
-#if ENABLE(DFG_JIT)
-    ASSERT(!visitor->isInlinedFrame());
-#endif
-
-    CallFrame* callFrame = visitor->callFrame();
-    unsigned exceptionHandlerIndex;
-    if (JITCode::isOptimizingJIT(codeBlock->jitType()))
-        exceptionHandlerIndex = callFrame->callSiteIndex().bits();
-    else
-        exceptionHandlerIndex = callFrame->bytecodeOffset();
-
-    return codeBlock->handlerForIndex(exceptionHandlerIndex, requiredHandler);
-}
-
-class GetCatchHandlerFunctor {
+class GetExceptionHandlerFunctor {
 public:
-    GetCatchHandlerFunctor()
+    GetExceptionHandlerFunctor()
         : m_handler(0)
     {
     }
@@ -624,13 +608,12 @@ public:
 
     StackVisitor::Status operator()(StackVisitor& visitor)
     {
-        visitor.unwindToMachineCodeBlockFrame();
-
         CodeBlock* codeBlock = visitor->codeBlock();
         if (!codeBlock)
             return StackVisitor::Continue;
 
-        m_handler = findExceptionHandler(visitor, codeBlock, CodeBlock::RequiredHandler::CatchHandler);
+        unsigned bytecodeOffset = visitor->bytecodeOffset();
+        m_handler = codeBlock->handlerForBytecodeOffset(bytecodeOffset);
         if (m_handler)
             return StackVisitor::Done;
 
@@ -641,18 +624,6 @@ private:
     HandlerInfo* m_handler;
 };
 
-ALWAYS_INLINE static void notifyDebuggerOfUnwinding(CallFrame* callFrame)
-{
-    if (Debugger* debugger = callFrame->vmEntryGlobalObject()->debugger()) {
-        SuspendExceptionScope scope(&callFrame->vm());
-        if (jsDynamicCast<JSFunction*>(callFrame->callee()))
-            debugger->returnEvent(callFrame);
-        else
-            debugger->didExecuteProgram(callFrame);
-        ASSERT(!callFrame->hadException());
-    }
-}
-
 class UnwindFunctor {
 public:
     UnwindFunctor(CallFrame*& callFrame, bool isTermination, CodeBlock*& codeBlock, HandlerInfo*& handler)
@@ -665,92 +636,35 @@ public:
 
     StackVisitor::Status operator()(StackVisitor& visitor)
     {
-        visitor.unwindToMachineCodeBlockFrame();
         VM& vm = m_callFrame->vm();
         m_callFrame = visitor->callFrame();
         m_codeBlock = visitor->codeBlock();
+        unsigned bytecodeOffset = visitor->bytecodeOffset();
 
-        m_handler = nullptr;
-        if (!m_isTermination) {
-            if (m_codeBlock && !isWebAssemblyExecutable(m_codeBlock->ownerExecutable()))
-                m_handler = findExceptionHandler(visitor, m_codeBlock, CodeBlock::RequiredHandler::AnyHandler);
-        }
-
-        if (m_handler)
-            return StackVisitor::Done;
-
-        notifyDebuggerOfUnwinding(m_callFrame);
-
-        bool shouldStopUnwinding = visitor->callerIsVMEntryFrame();
-        if (shouldStopUnwinding) {
-            if (LegacyProfiler* profiler = vm.enabledProfiler())
-                profiler->exceptionUnwind(m_callFrame);
-
-            copyCalleeSavesToVMCalleeSavesBuffer(visitor);
-
+        if (m_isTermination || !(m_handler = m_codeBlock->handlerForBytecodeOffset(bytecodeOffset))) {
+            if (!unwindCallFrame(visitor)) {
+                if (LegacyProfiler* profiler = vm.enabledProfiler())
+                    profiler->exceptionUnwind(m_callFrame);
+                return StackVisitor::Done;
+            }
+        } else
             return StackVisitor::Done;
-        }
-
-        copyCalleeSavesToVMCalleeSavesBuffer(visitor);
 
         return StackVisitor::Continue;
     }
 
 private:
-    void copyCalleeSavesToVMCalleeSavesBuffer(StackVisitor& visitor)
-    {
-#if ENABLE(JIT) && NUMBER_OF_CALLEE_SAVES_REGISTERS > 0
-
-        if (!visitor->isJSFrame())
-            return;
-
-#if ENABLE(DFG_JIT)
-        if (visitor->inlineCallFrame())
-            return;
-#endif
-        RegisterAtOffsetList* currentCalleeSaves = m_codeBlock ? m_codeBlock->calleeSaveRegisters() : nullptr;
-
-        if (!currentCalleeSaves)
-            return;
-
-        VM& vm = m_callFrame->vm();
-        RegisterAtOffsetList* allCalleeSaves = vm.getAllCalleeSaveRegisterOffsets();
-        RegisterSet dontCopyRegisters = RegisterSet::stackRegisters();
-        intptr_t* frame = reinterpret_cast<intptr_t*>(m_callFrame->registers());
-
-        unsigned registerCount = currentCalleeSaves->size();
-        for (unsigned i = 0; i < registerCount; i++) {
-            RegisterAtOffset currentEntry = currentCalleeSaves->at(i);
-            if (dontCopyRegisters.get(currentEntry.reg()))
-                continue;
-            RegisterAtOffset* vmCalleeSavesEntry = allCalleeSaves->find(currentEntry.reg());
-            
-            vm.calleeSaveRegistersBuffer[vmCalleeSavesEntry->offsetAsIndex()] = *(frame + currentEntry.offsetAsIndex());
-        }
-#else
-        UNUSED_PARAM(visitor);
-#endif
-    }
-
     CallFrame*& m_callFrame;
     bool m_isTermination;
     CodeBlock*& m_codeBlock;
     HandlerInfo*& m_handler;
 };
 
-NEVER_INLINE HandlerInfo* Interpreter::unwind(VM& vm, CallFrame*& callFrame, Exception* exception, UnwindStart unwindStart)
+NEVER_INLINE HandlerInfo* Interpreter::unwind(CallFrame*& callFrame, JSValue& exceptionValue)
 {
-    if (unwindStart == UnwindFromCallerFrame) {
-        if (callFrame->callerFrameOrVMEntryFrame() == vm.topVMEntryFrame)
-            return nullptr;
-
-        callFrame = callFrame->callerFrame();
-        vm.topCallFrame = callFrame;
-    }
-
     CodeBlock* codeBlock = callFrame->codeBlock();
+    bool isTermination = false;
 
-    JSValue exceptionValue = exception->value();
     ASSERT(!exceptionValue.isEmpty());
     ASSERT(!exceptionValue.isCell() || exceptionValue.asCell());
     // This shouldn't be possible (hence the assertions), but we're already in the slowest of
@@ -758,42 +672,60 @@ NEVER_INLINE HandlerInfo* Interpreter::unwind(VM& vm, CallFrame*& callFrame, Exc
     if (exceptionValue.isEmpty() || (exceptionValue.isCell() && !exceptionValue.asCell()))
         exceptionValue = jsNull();
 
-    ASSERT(vm.exception() && vm.exception()->stack().size());
-
-    // Calculate an exception handler vPC, unwinding call frames as necessary.
-    HandlerInfo* handler = nullptr;
-    UnwindFunctor functor(callFrame, isTerminatedExecutionException(exception), codeBlock, handler);
-    callFrame->iterate(functor);
-    if (!handler)
-        return nullptr;
+    if (exceptionValue.isObject()) {
+        isTermination = isTerminatedExecutionException(asObject(exceptionValue));
+    }
 
-    return handler;
-}
+    ASSERT(callFrame->vm().exceptionStack().size());
 
-void Interpreter::notifyDebuggerOfExceptionToBeThrown(CallFrame* callFrame, Exception* exception)
-{
     Debugger* debugger = callFrame->vmEntryGlobalObject()->debugger();
-    if (debugger && debugger->needsExceptionCallbacks() && !exception->didNotifyInspectorOfThrow()) {
+    if (debugger && debugger->needsExceptionCallbacks()) {
+        // We need to clear the exception and the exception stack here in order to see if a new exception happens.
+        // Afterwards, the values are put back to continue processing this error.
+        ClearExceptionScope scope(&callFrame->vm());
         // This code assumes that if the debugger is enabled then there is no inlining.
         // If that assumption turns out to be false then we'll ignore the inlined call
         // frames.
         // https://bugs.webkit.org/show_bug.cgi?id=121754
 
-        bool hasCatchHandler;
-        bool isTermination = isTerminatedExecutionException(exception);
+        bool hasHandler;
         if (isTermination)
-            hasCatchHandler = false;
+            hasHandler = false;
         else {
-            GetCatchHandlerFunctor functor;
+            GetExceptionHandlerFunctor functor;
             callFrame->iterate(functor);
-            HandlerInfo* handler = functor.handler();
-            ASSERT(!handler || handler->isCatchHandler());
-            hasCatchHandler = !!handler;
+            hasHandler = !!functor.handler();
         }
 
-        debugger->exception(callFrame, exception->value(), hasCatchHandler);
+        debugger->exception(callFrame, exceptionValue, hasHandler);
     }
-    exception->setDidNotifyInspectorOfThrow();
+
+    // Calculate an exception handler vPC, unwinding call frames as necessary.
+    HandlerInfo* handler = 0;
+    VM& vm = callFrame->vm();
+    ASSERT(callFrame == vm.topCallFrame);
+    UnwindFunctor functor(callFrame, isTermination, codeBlock, handler);
+    callFrame->iterate(functor);
+    if (!handler)
+        return 0;
+
+    if (LegacyProfiler* profiler = vm.enabledProfiler())
+        profiler->exceptionUnwind(callFrame);
+
+    // Unwind the scope chain within the exception handler's call frame.
+    int targetScopeDepth = handler->scopeDepth;
+    if (codeBlock->needsActivation() && callFrame->uncheckedR(codeBlock->activationRegister().offset()).jsValue())
+        ++targetScopeDepth;
+
+    JSScope* scope = callFrame->scope();
+    int scopeDelta = scope->depth() - targetScopeDepth;
+    RELEASE_ASSERT(scopeDelta >= 0);
+
+    while (scopeDelta--)
+        scope = scope->next();
+    callFrame->setScope(scope);
+
+    return handler;
 }
 
 static inline JSValue checkedReturn(JSValue returnValue)
@@ -826,16 +758,16 @@ private:
 JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, JSObject* thisObj)
 {
     SamplingScope samplingScope(this);
-
-    JSScope* scope = thisObj->globalObject()->globalScope();
+    
+    JSScope* scope = callFrame->scope();
     VM& vm = *scope->vm();
 
     ASSERT(!vm.exception());
     ASSERT(!vm.isCollectorBusy());
-    RELEASE_ASSERT(vm.currentThreadIsHoldingAPILock());
     if (vm.isCollectorBusy())
         return jsNull();
 
+    VMEntryScope entryScope(vm, scope->globalObject());
     if (!vm.isSafeToRecurse())
         return checkedReturn(throwStackOverflowError(callFrame));
 
@@ -845,7 +777,7 @@ JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, J
 
     Vector<JSONPData> JSONPData;
     bool parseResult;
-    StringView programSource = program->source().view();
+    const String programSource = program->source().toString();
     if (programSource.isNull())
         return jsUndefined();
     if (programSource.is8Bit()) {
@@ -876,10 +808,10 @@ JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, J
                 switch (JSONPPath[i].m_type) {
                 case JSONPPathEntryTypeDot: {
                     if (i == 0) {
-                        PropertySlot slot(globalObject, PropertySlot::InternalMethodType::Get);
+                        PropertySlot slot(globalObject);
                         if (!globalObject->getPropertySlot(callFrame, JSONPPath[i].m_pathEntryName, slot)) {
                             if (entry)
-                                return callFrame->vm().throwException(callFrame, createUndefinedVariableError(callFrame, JSONPPath[i].m_pathEntryName));
+                                return callFrame->vm().throwException(callFrame, createUndefinedVariableError(globalObject->globalExec(), JSONPPath[i].m_pathEntryName));
                             goto failedJSONP;
                         }
                         baseObject = slot.getValue(callFrame, JSONPPath[i].m_pathEntryName);
@@ -942,37 +874,40 @@ failedJSONP:
     // If we get here, then we have already proven that the script is not a JSON
     // object.
 
-    VMEntryScope entryScope(vm, scope->globalObject());
-
     // Compile source to bytecode if necessary:
     if (JSObject* error = program->initializeGlobalProperties(vm, callFrame, scope))
         return checkedReturn(callFrame->vm().throwException(callFrame, error));
 
-    if (JSObject* error = program->prepareForExecution(callFrame, nullptr, scope, CodeForCall))
+    if (JSObject* error = program->prepareForExecution(callFrame, scope, CodeForCall))
         return checkedReturn(callFrame->vm().throwException(callFrame, error));
 
     ProgramCodeBlock* codeBlock = program->codeBlock();
 
-    if (UNLIKELY(vm.shouldTriggerTermination(callFrame)))
+    if (UNLIKELY(vm.watchdog.didFire(callFrame)))
         return throwTerminatedExecutionException(callFrame);
 
     ASSERT(codeBlock->numParameters() == 1); // 1 parameter for 'this'.
 
+    if (UNLIKELY(!m_stack.entryCheck(codeBlock, 1)))
+        return checkedReturn(throwStackOverflowError(callFrame));
+
     ProtoCallFrame protoCallFrame;
-    protoCallFrame.init(codeBlock, JSCallee::create(vm, scope->globalObject(), scope), thisObj, 1);
+    protoCallFrame.init(codeBlock, scope, 0, thisObj, 1);
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
-        profiler->willExecute(callFrame, program->sourceURL(), program->firstLine(), program->startColumn());
+        profiler->willExecute(callFrame, program->sourceURL(), program->lineNo());
 
     // Execute the code:
     JSValue result;
     {
         SamplingTool::CallRecord callRecord(m_sampler.get());
-        result = program->generatedJITCode()->execute(&vm, &protoCallFrame);
+        Watchdog::Scope watchdogScope(vm.watchdog);
+
+        result = program->generatedJITCode()->execute(&vm, &protoCallFrame, m_stack.getTopOfStack());
     }
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
-        profiler->didExecute(callFrame, program->sourceURL(), program->firstLine(), program->startColumn());
+        profiler->didExecute(callFrame, program->sourceURL(), program->lineNo());
 
     return checkedReturn(result);
 }
@@ -986,27 +921,24 @@ JSValue Interpreter::executeCall(CallFrame* callFrame, JSObject* function, CallT
         return jsNull();
 
     bool isJSCall = (callType == CallTypeJS);
-    JSScope* scope = nullptr;
+    JSScope* scope;
     CodeBlock* newCodeBlock;
     size_t argsCount = 1 + args.size(); // implicit "this" parameter
 
-    JSGlobalObject* globalObject;
-
-    if (isJSCall) {
+    if (isJSCall)
         scope = callData.js.scope;
-        globalObject = scope->globalObject();
-    } else {
+    else {
         ASSERT(callType == CallTypeHost);
-        globalObject = function->globalObject();
+        scope = callFrame->scope();
     }
 
-    VMEntryScope entryScope(vm, globalObject);
+    VMEntryScope entryScope(vm, scope->globalObject());
     if (!vm.isSafeToRecurse())
         return checkedReturn(throwStackOverflowError(callFrame));
 
     if (isJSCall) {
         // Compile the callee:
-        JSObject* compileError = callData.js.functionExecutable->prepareForExecution(callFrame, jsCast<JSFunction*>(function), scope, CodeForCall);
+        JSObject* compileError = callData.js.functionExecutable->prepareForExecution(callFrame, scope, CodeForCall);
         if (UNLIKELY(!!compileError)) {
             return checkedReturn(callFrame->vm().throwException(callFrame, compileError));
         }
@@ -1016,11 +948,14 @@ JSValue Interpreter::executeCall(CallFrame* callFrame, JSObject* function, CallT
     } else
         newCodeBlock = 0;
 
-    if (UNLIKELY(vm.shouldTriggerTermination(callFrame)))
+    if (UNLIKELY(vm.watchdog.didFire(callFrame)))
         return throwTerminatedExecutionException(callFrame);
 
+    if (UNLIKELY(!m_stack.entryCheck(newCodeBlock, argsCount)))
+        return checkedReturn(throwStackOverflowError(callFrame));
+
     ProtoCallFrame protoCallFrame;
-    protoCallFrame.init(newCodeBlock, function, thisValue, argsCount, args.data());
+    protoCallFrame.init(newCodeBlock, scope, function, thisValue, argsCount, args.data());
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
         profiler->willExecute(callFrame, function);
@@ -1028,15 +963,13 @@ JSValue Interpreter::executeCall(CallFrame* callFrame, JSObject* function, CallT
     JSValue result;
     {
         SamplingTool::CallRecord callRecord(m_sampler.get(), !isJSCall);
+        Watchdog::Scope watchdogScope(vm.watchdog);
 
         // Execute the code:
         if (isJSCall)
-            result = callData.js.functionExecutable->generatedJITCodeForCall()->execute(&vm, &protoCallFrame);
-        else {
-            result = JSValue::decode(vmEntryToNative(reinterpret_cast<void*>(callData.native.function), &vm, &protoCallFrame));
-            if (callFrame->hadException())
-                result = jsNull();
-        }
+            result = callData.js.functionExecutable->generatedJITCodeForCall()->execute(&vm, &protoCallFrame, m_stack.getTopOfStack());
+        else
+            result = JSValue::decode(callToNativeFunction(reinterpret_cast<void*>(callData.native.function), &vm.topCallFrame, &protoCallFrame, m_stack.getTopOfStack()));
     }
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
@@ -1045,7 +978,7 @@ JSValue Interpreter::executeCall(CallFrame* callFrame, JSObject* function, CallT
     return checkedReturn(result);
 }
 
-JSObject* Interpreter::executeConstruct(CallFrame* callFrame, JSObject* constructor, ConstructType constructType, const ConstructData& constructData, const ArgList& args, JSValue newTarget)
+JSObject* Interpreter::executeConstruct(CallFrame* callFrame, JSObject* constructor, ConstructType constructType, const ConstructData& constructData, const ArgList& args)
 {
     VM& vm = callFrame->vm();
     ASSERT(!callFrame->hadException());
@@ -1056,27 +989,24 @@ JSObject* Interpreter::executeConstruct(CallFrame* callFrame, JSObject* construc
         return checkedReturn(throwStackOverflowError(callFrame));
 
     bool isJSConstruct = (constructType == ConstructTypeJS);
-    JSScope* scope = nullptr;
+    JSScope* scope;
     CodeBlock* newCodeBlock;
     size_t argsCount = 1 + args.size(); // implicit "this" parameter
 
-    JSGlobalObject* globalObject;
-
-    if (isJSConstruct) {
+    if (isJSConstruct)
         scope = constructData.js.scope;
-        globalObject = scope->globalObject();
-    } else {
+    else {
         ASSERT(constructType == ConstructTypeHost);
-        globalObject = constructor->globalObject();
+        scope = callFrame->scope();
     }
 
-    VMEntryScope entryScope(vm, globalObject);
+    VMEntryScope entryScope(vm, scope->globalObject());
     if (!vm.isSafeToRecurse())
         return checkedReturn(throwStackOverflowError(callFrame));
 
     if (isJSConstruct) {
         // Compile the callee:
-        JSObject* compileError = constructData.js.functionExecutable->prepareForExecution(callFrame, jsCast<JSFunction*>(constructor), scope, CodeForConstruct);
+        JSObject* compileError = constructData.js.functionExecutable->prepareForExecution(callFrame, scope, CodeForConstruct);
         if (UNLIKELY(!!compileError)) {
             return checkedReturn(callFrame->vm().throwException(callFrame, compileError));
         }
@@ -1086,11 +1016,14 @@ JSObject* Interpreter::executeConstruct(CallFrame* callFrame, JSObject* construc
     } else
         newCodeBlock = 0;
 
-    if (UNLIKELY(vm.shouldTriggerTermination(callFrame)))
+    if (UNLIKELY(vm.watchdog.didFire(callFrame)))
         return throwTerminatedExecutionException(callFrame);
 
+    if (UNLIKELY(!m_stack.entryCheck(newCodeBlock, argsCount)))
+        return checkedReturn(throwStackOverflowError(callFrame));
+
     ProtoCallFrame protoCallFrame;
-    protoCallFrame.init(newCodeBlock, constructor, newTarget, argsCount, args.data());
+    protoCallFrame.init(newCodeBlock, scope, constructor, jsUndefined(), argsCount, args.data());
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
         profiler->willExecute(callFrame, constructor);
@@ -1098,12 +1031,13 @@ JSObject* Interpreter::executeConstruct(CallFrame* callFrame, JSObject* construc
     JSValue result;
     {
         SamplingTool::CallRecord callRecord(m_sampler.get(), !isJSConstruct);
+        Watchdog::Scope watchdogScope(vm.watchdog);
 
         // Execute the code.
         if (isJSConstruct)
-            result = constructData.js.functionExecutable->generatedJITCodeForConstruct()->execute(&vm, &protoCallFrame);
+            result = constructData.js.functionExecutable->generatedJITCodeForConstruct()->execute(&vm, &protoCallFrame, m_stack.getTopOfStack());
         else {
-            result = JSValue::decode(vmEntryToNative(reinterpret_cast<void*>(constructData.native.function), &vm, &protoCallFrame));
+            result = JSValue::decode(callToNativeFunction(reinterpret_cast<void*>(constructData.native.function), &vm.topCallFrame, &protoCallFrame, m_stack.getTopOfStack()));
 
             if (!callFrame->hadException())
                 RELEASE_ASSERT(result.isObject());
@@ -1128,7 +1062,7 @@ CallFrameClosure Interpreter::prepareForRepeatCall(FunctionExecutable* functionE
         return CallFrameClosure();
 
     // Compile the callee:
-    JSObject* error = functionExecutable->prepareForExecution(callFrame, function, scope, CodeForCall);
+    JSObject* error = functionExecutable->prepareForExecution(callFrame, scope, CodeForCall);
     if (error) {
         callFrame->vm().throwException(callFrame, error);
         return CallFrameClosure();
@@ -1138,7 +1072,12 @@ CallFrameClosure Interpreter::prepareForRepeatCall(FunctionExecutable* functionE
 
     size_t argsCount = argumentCountIncludingThis;
 
-    protoCallFrame->init(newCodeBlock, function, jsUndefined(), argsCount, args);
+    if (UNLIKELY(!m_stack.entryCheck(newCodeBlock, argsCount))) {
+        throwStackOverflowError(callFrame);
+        return CallFrameClosure();
+    }
+
+    protoCallFrame->init(newCodeBlock, scope, function, jsUndefined(), argsCount, args);
     // Return the successful closure:
     CallFrameClosure result = { callFrame, protoCallFrame, function, functionExecutable, &vm, scope, newCodeBlock->numParameters(), argumentCountIncludingThis };
     return result;
@@ -1150,23 +1089,25 @@ JSValue Interpreter::execute(CallFrameClosure& closure)
     SamplingScope samplingScope(this);
     
     ASSERT(!vm.isCollectorBusy());
-    RELEASE_ASSERT(vm.currentThreadIsHoldingAPILock());
     if (vm.isCollectorBusy())
         return jsNull();
 
     StackStats::CheckPoint stackCheckPoint;
+    closure.resetCallFrame();
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
         profiler->willExecute(closure.oldCallFrame, closure.function);
 
-    if (UNLIKELY(vm.shouldTriggerTermination(closure.oldCallFrame)))
+    if (UNLIKELY(vm.watchdog.didFire(closure.oldCallFrame)))
         return throwTerminatedExecutionException(closure.oldCallFrame);
 
     // Execute the code:
     JSValue result;
     {
         SamplingTool::CallRecord callRecord(m_sampler.get());
-        result = closure.functionExecutable->generatedJITCodeForCall()->execute(&vm, closure.protoCallFrame);
+        Watchdog::Scope watchdogScope(vm.watchdog);
+
+        result = closure.functionExecutable->generatedJITCodeForCall()->execute(&vm, closure.protoCallFrame, m_stack.getTopOfStack());
     }
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
@@ -1183,7 +1124,6 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSValue
     ASSERT(scope->vm() == &callFrame->vm());
     ASSERT(!vm.exception());
     ASSERT(!vm.isCollectorBusy());
-    RELEASE_ASSERT(vm.currentThreadIsHoldingAPILock());
     if (vm.isCollectorBusy())
         return jsNull();
 
@@ -1196,55 +1136,27 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSValue
 
     JSScope* variableObject;
     if ((numVariables || numFunctions) && eval->isStrictMode()) {
-        scope = StrictEvalActivation::create(callFrame, scope);
+        scope = StrictEvalActivation::create(callFrame);
         variableObject = scope;
     } else {
         for (JSScope* node = scope; ; node = node->next()) {
             RELEASE_ASSERT(node);
-            if (node->isGlobalObject()) {
+            if (node->isVariableObject() && !node->isNameScopeObject()) {
                 variableObject = node;
                 break;
-            } 
-            if (JSLexicalEnvironment* lexicalEnvironment = jsDynamicCast<JSLexicalEnvironment*>(node)) {
-                if (lexicalEnvironment->symbolTable()->scopeType() == SymbolTable::ScopeType::VarScope) {
-                    variableObject = node;
-                    break;
-                }
             }
         }
     }
 
-    JSObject* compileError = eval->prepareForExecution(callFrame, nullptr, scope, CodeForCall);
+    JSObject* compileError = eval->prepareForExecution(callFrame, scope, CodeForCall);
     if (UNLIKELY(!!compileError))
         return checkedReturn(callFrame->vm().throwException(callFrame, compileError));
     EvalCodeBlock* codeBlock = eval->codeBlock();
 
-    // We can't declare a "var"/"function" that overwrites a global "let"/"const"/"class" in a sloppy-mode eval.
-    if (variableObject->isGlobalObject() && !eval->isStrictMode() && (numVariables || numFunctions)) {
-        JSGlobalLexicalEnvironment* globalLexicalEnvironment = jsCast<JSGlobalObject*>(variableObject)->globalLexicalEnvironment();
-        for (unsigned i = 0; i < numVariables; ++i) {
-            const Identifier& ident = codeBlock->variable(i);
-            PropertySlot slot(globalLexicalEnvironment, PropertySlot::InternalMethodType::VMInquiry);
-            if (JSGlobalLexicalEnvironment::getOwnPropertySlot(globalLexicalEnvironment, callFrame, ident, slot)) {
-                return checkedReturn(callFrame->vm().throwException(callFrame,
-                    createTypeError(callFrame, makeString("Can't create duplicate global variable in eval: '", String(ident.impl()), "'"))));
-            }
-        }
-
-        for (int i = 0; i < numFunctions; ++i) {
-            FunctionExecutable* function = codeBlock->functionDecl(i);
-            PropertySlot slot(globalLexicalEnvironment, PropertySlot::InternalMethodType::VMInquiry);
-            if (JSGlobalLexicalEnvironment::getOwnPropertySlot(globalLexicalEnvironment, callFrame, function->name(), slot)) {
-                return checkedReturn(callFrame->vm().throwException(callFrame,
-                    createTypeError(callFrame, makeString("Can't create duplicate global variable in eval: '", String(function->name().impl()), "'"))));
-            }
-        }
-    }
-
     if (numVariables || numFunctions) {
         BatchedTransitionOptimizer optimizer(vm, variableObject);
         if (variableObject->next())
-            variableObject->globalObject()->varInjectionWatchpoint()->fireAll("Executed eval, fired VarInjection watchpoint");
+            variableObject->globalObject()->varInjectionWatchpoint()->fireAll();
 
         for (unsigned i = 0; i < numVariables; ++i) {
             const Identifier& ident = codeBlock->variable(i);
@@ -1261,74 +1173,31 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSValue
         }
     }
 
-    if (UNLIKELY(vm.shouldTriggerTermination(callFrame)))
+    if (UNLIKELY(vm.watchdog.didFire(callFrame)))
         return throwTerminatedExecutionException(callFrame);
 
     ASSERT(codeBlock->numParameters() == 1); // 1 parameter for 'this'.
 
-    ProtoCallFrame protoCallFrame;
-    protoCallFrame.init(codeBlock, JSCallee::create(vm, scope->globalObject(), scope), thisValue, 1);
-
-    if (LegacyProfiler* profiler = vm.enabledProfiler())
-        profiler->willExecute(callFrame, eval->sourceURL(), eval->firstLine(), eval->startColumn());
-
-    // Execute the code:
-    JSValue result;
-    {
-        SamplingTool::CallRecord callRecord(m_sampler.get());
-        result = eval->generatedJITCode()->execute(&vm, &protoCallFrame);
-    }
-
-    if (LegacyProfiler* profiler = vm.enabledProfiler())
-        profiler->didExecute(callFrame, eval->sourceURL(), eval->firstLine(), eval->startColumn());
-
-    return checkedReturn(result);
-}
-
-JSValue Interpreter::execute(ModuleProgramExecutable* executable, CallFrame* callFrame, JSModuleEnvironment* scope)
-{
-    VM& vm = *scope->vm();
-    SamplingScope samplingScope(this);
-
-    ASSERT(scope->vm() == &callFrame->vm());
-    ASSERT(!vm.exception());
-    ASSERT(!vm.isCollectorBusy());
-    RELEASE_ASSERT(vm.currentThreadIsHoldingAPILock());
-    if (vm.isCollectorBusy())
-        return jsNull();
-
-    VMEntryScope entryScope(vm, scope->globalObject());
-    if (!vm.isSafeToRecurse())
+    if (UNLIKELY(!m_stack.entryCheck(codeBlock, 1)))
         return checkedReturn(throwStackOverflowError(callFrame));
 
-    JSObject* compileError = executable->prepareForExecution(callFrame, nullptr, scope, CodeForCall);
-    if (UNLIKELY(!!compileError))
-        return checkedReturn(callFrame->vm().throwException(callFrame, compileError));
-    ModuleProgramCodeBlock* codeBlock = executable->codeBlock();
-
-    if (UNLIKELY(vm.shouldTriggerTermination(callFrame)))
-        return throwTerminatedExecutionException(callFrame);
-
-    ASSERT(codeBlock->numParameters() == 1); // 1 parameter for 'this'.
-
-    // The |this| of the module is always `undefined`.
-    // http://www.ecma-international.org/ecma-262/6.0/#sec-module-environment-records-hasthisbinding
-    // http://www.ecma-international.org/ecma-262/6.0/#sec-module-environment-records-getthisbinding
     ProtoCallFrame protoCallFrame;
-    protoCallFrame.init(codeBlock, JSCallee::create(vm, scope->globalObject(), scope), jsUndefined(), 1);
+    protoCallFrame.init(codeBlock, scope, 0, thisValue, 1);
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
-        profiler->willExecute(callFrame, executable->sourceURL(), executable->firstLine(), executable->startColumn());
+        profiler->willExecute(callFrame, eval->sourceURL(), eval->lineNo());
 
     // Execute the code:
     JSValue result;
     {
         SamplingTool::CallRecord callRecord(m_sampler.get());
-        result = executable->generatedJITCode()->execute(&vm, &protoCallFrame);
+        Watchdog::Scope watchdogScope(vm.watchdog);
+
+        result = eval->generatedJITCode()->execute(&vm, &protoCallFrame, m_stack.getTopOfStack());
     }
 
     if (LegacyProfiler* profiler = vm.enabledProfiler())
-        profiler->didExecute(callFrame, executable->sourceURL(), executable->firstLine(), executable->startColumn());
+        profiler->didExecute(callFrame, eval->sourceURL(), eval->lineNo());
 
     return checkedReturn(result);
 }
@@ -1338,38 +1207,35 @@ NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHook
     Debugger* debugger = callFrame->vmEntryGlobalObject()->debugger();
     if (!debugger)
         return;
-
-    ASSERT(callFrame->codeBlock()->hasDebuggerRequests());
-    ASSERT(!callFrame->hadException());
+    ASSERT(callFrame->codeBlock()->hasDebuggerRequests() || callFrame->hadException());
 
     switch (debugHookID) {
         case DidEnterCallFrame:
             debugger->callEvent(callFrame);
-            break;
+            return;
         case WillLeaveCallFrame:
             debugger->returnEvent(callFrame);
-            break;
+            return;
         case WillExecuteStatement:
             debugger->atStatement(callFrame);
-            break;
+            return;
         case WillExecuteProgram:
             debugger->willExecuteProgram(callFrame);
-            break;
+            return;
         case DidExecuteProgram:
             debugger->didExecuteProgram(callFrame);
-            break;
+            return;
         case DidReachBreakpoint:
             debugger->didReachBreakpoint(callFrame);
-            break;
+            return;
     }
-    ASSERT(!callFrame->hadException());
 }    
 
 void Interpreter::enableSampler()
 {
 #if ENABLE(OPCODE_SAMPLING)
     if (!m_sampler) {
-        m_sampler = std::make_unique<SamplingTool>(this);
+        m_sampler = adoptPtr(new SamplingTool(this));
         m_sampler->setup();
     }
 #endif