webkitgtk-2.12.3webkitgtk-2.12.3

12 files changed, 842 insertions, 390 deletions

diff --git a/Source/JavaScriptCore/debugger/Breakpoint.h b/Source/JavaScriptCore/debugger/Breakpoint.h
index 95b92881d..78d208a2b 100644
--- a/Source/JavaScriptCore/debugger/Breakpoint.h
+++ b/Source/JavaScriptCore/debugger/Breakpoint.h
@@ -27,38 +27,67 @@
 #define Breakpoint_h
 
 #include "DebuggerPrimitives.h"
+#include <wtf/DoublyLinkedList.h>
+#include <wtf/RefCounted.h>
 #include <wtf/text/WTFString.h>
 
 namespace JSC {
 
-struct Breakpoint {
+struct Breakpoint : public DoublyLinkedListNode<Breakpoint> {
     Breakpoint()
-        : id(noBreakpointID)
-        , sourceID(noSourceID)
-        , line(0)
-        , column(0)
-        , autoContinue(false)
     {
     }
 
-    Breakpoint(SourceID sourceID, unsigned line, unsigned column, String condition, bool autoContinue)
-        : id(noBreakpointID)
-        , sourceID(sourceID)
+    Breakpoint(SourceID sourceID, unsigned line, unsigned column, const String& condition, bool autoContinue, unsigned ignoreCount)
+        : sourceID(sourceID)
         , line(line)
         , column(column)
         , condition(condition)
         , autoContinue(autoContinue)
+        , ignoreCount(ignoreCount)
     {
     }
 
-    BreakpointID id;
-    SourceID sourceID;
-    unsigned line;
-    unsigned column;
+    Breakpoint(const Breakpoint& other)
+        : id(other.id)
+        , sourceID(other.sourceID)
+        , line(other.line)
+        , column(other.column)
+        , condition(other.condition)
+        , autoContinue(other.autoContinue)
+        , ignoreCount(other.ignoreCount)
+        , hitCount(other.hitCount)
+    {
+    }
+
+    BreakpointID id { noBreakpointID };
+    SourceID sourceID { noSourceID };
+    unsigned line { 0 };
+    unsigned column { 0 };
     String condition;
-    bool autoContinue;
+    bool autoContinue { false };
+    unsigned ignoreCount { 0 };
+    unsigned hitCount { 0 };
 
     static const unsigned unspecifiedColumn = UINT_MAX;
+
+private:
+    Breakpoint* m_prev;
+    Breakpoint* m_next;
+
+    friend class WTF::DoublyLinkedListNode<Breakpoint>;
+};
+
+class BreakpointsList : public DoublyLinkedList<Breakpoint>,
+    public RefCounted<BreakpointsList> {
+public:
+    ~BreakpointsList()
+    {
+        Breakpoint* breakpoint;
+        while ((breakpoint = removeHead()))
+            delete breakpoint;
+        ASSERT(isEmpty());
+    }
 };
 
 } // namespace JSC
diff --git a/Source/JavaScriptCore/debugger/Debugger.cpp b/Source/JavaScriptCore/debugger/Debugger.cpp
index afa7546c8..f50d54be5 100644
--- a/Source/JavaScriptCore/debugger/Debugger.cpp
+++ b/Source/JavaScriptCore/debugger/Debugger.cpp
@@ -25,13 +25,12 @@
 #include "CodeBlock.h"
 #include "DebuggerCallFrame.h"
 #include "Error.h"
-
 #include "HeapIterationScope.h"
 #include "Interpreter.h"
 #include "JSCJSValueInlines.h"
 #include "JSFunction.h"
 #include "JSGlobalObject.h"
-#include "Operations.h"
+#include "JSCInlines.h"
 #include "Parser.h"
 #include "Protect.h"
 #include "VMEntryScope.h"
@@ -40,65 +39,41 @@ namespace {
 
 using namespace JSC;
 
-class Recompiler : public MarkedBlock::VoidFunctor {
-public:
-    Recompiler(JSC::Debugger*);
-    ~Recompiler();
-    void operator()(JSCell*);
-
-private:
-    typedef HashSet<FunctionExecutable*> FunctionExecutableSet;
-    typedef HashMap<SourceProvider*, ExecState*> SourceProviderMap;
-    
-    JSC::Debugger* m_debugger;
-    FunctionExecutableSet m_functionExecutables;
-    SourceProviderMap m_sourceProviders;
-};
-
-inline Recompiler::Recompiler(JSC::Debugger* debugger)
-    : m_debugger(debugger)
-{
-}
+struct GatherSourceProviders : public MarkedBlock::VoidFunctor {
+    HashSet<SourceProvider*> sourceProviders;
+    JSGlobalObject* m_globalObject;
 
-inline Recompiler::~Recompiler()
-{
-    // Call sourceParsed() after reparsing all functions because it will execute
-    // JavaScript in the inspector.
-    SourceProviderMap::const_iterator end = m_sourceProviders.end();
-    for (SourceProviderMap::const_iterator iter = m_sourceProviders.begin(); iter != end; ++iter)
-        m_debugger->sourceParsed(iter->value, iter->key, -1, String());
-}
+    GatherSourceProviders(JSGlobalObject* globalObject)
+        : m_globalObject(globalObject) { }
 
-inline void Recompiler::operator()(JSCell* cell)
-{
-    if (!cell->inherits(JSFunction::info()))
-        return;
+    IterationStatus operator()(JSCell* cell)
+    {
+        JSFunction* function = jsDynamicCast<JSFunction*>(cell);
+        if (!function)
+            return IterationStatus::Continue;
 
-    JSFunction* function = jsCast<JSFunction*>(cell);
-    if (function->executable()->isHostFunction())
-        return;
+        if (function->scope()->globalObject() != m_globalObject)
+            return IterationStatus::Continue;
 
-    FunctionExecutable* executable = function->jsExecutable();
+        if (!function->executable()->isFunctionExecutable())
+            return IterationStatus::Continue;
 
-    // Check if the function is already in the set - if so,
-    // we've already retranslated it, nothing to do here.
-    if (!m_functionExecutables.add(executable).isNewEntry)
-        return;
+        if (function->isHostOrBuiltinFunction())
+            return IterationStatus::Continue;
 
-    ExecState* exec = function->scope()->globalObject()->JSGlobalObject::globalExec();
-    executable->clearCodeIfNotCompiling();
-    executable->clearUnlinkedCodeForRecompilationIfNotCompiling();
-    if (m_debugger == function->scope()->globalObject()->debugger())
-        m_sourceProviders.add(executable->source().provider(), exec);
-}
+        sourceProviders.add(
+            jsCast<FunctionExecutable*>(function->executable())->source().provider());
+        return IterationStatus::Continue;
+    }
+};
 
 } // namespace
 
 namespace JSC {
 
-class DebuggerCallFrameScope {
+class DebuggerPausedScope {
 public:
-    DebuggerCallFrameScope(Debugger& debugger)
+    DebuggerPausedScope(Debugger& debugger)
         : m_debugger(debugger)
     {
         ASSERT(!m_debugger.m_currentDebuggerCallFrame);
@@ -106,11 +81,11 @@ public:
             m_debugger.m_currentDebuggerCallFrame = DebuggerCallFrame::create(debugger.m_currentCallFrame);
     }
 
-    ~DebuggerCallFrameScope()
+    ~DebuggerPausedScope()
     {
         if (m_debugger.m_currentDebuggerCallFrame) {
             m_debugger.m_currentDebuggerCallFrame->invalidate();
-            m_debugger.m_currentDebuggerCallFrame = 0;
+            m_debugger.m_currentDebuggerCallFrame = nullptr;
         }
     }
 
@@ -138,14 +113,14 @@ private:
     Debugger& m_debugger;
 };
 
-Debugger::Debugger(bool isInWorkerThread)
-    : m_vm(nullptr)
+Debugger::Debugger(VM& vm)
+    : m_vm(vm)
     , m_pauseOnExceptionsState(DontPauseOnExceptions)
     , m_pauseOnNextStatement(false)
     , m_isPaused(false)
     , m_breakpointsActivated(true)
     , m_hasHandlerForExceptionCallback(false)
-    , m_isInWorkerThread(isInWorkerThread)
+    , m_suppressAllPauses(false)
     , m_steppingMode(SteppingModeDisabled)
     , m_reasonForPause(NotPaused)
     , m_pauseOnCallFrame(0)
@@ -153,6 +128,7 @@ Debugger::Debugger(bool isInWorkerThread)
     , m_lastExecutedLine(UINT_MAX)
     , m_lastExecutedSourceID(noSourceID)
     , m_topBreakpointID(noBreakpointID)
+    , m_pausingBreakpointID(noBreakpointID)
 {
 }
 
@@ -166,12 +142,19 @@ Debugger::~Debugger()
 void Debugger::attach(JSGlobalObject* globalObject)
 {
     ASSERT(!globalObject->debugger());
-    if (!m_vm)
-        m_vm = &globalObject->vm();
-    else
-        ASSERT(m_vm == &globalObject->vm());
     globalObject->setDebugger(this);
     m_globalObjects.add(globalObject);
+
+    m_vm.setShouldBuildPCToCodeOriginMapping();
+
+    // Call sourceParsed because it will execute JavaScript in the inspector.
+    GatherSourceProviders gatherSourceProviders(globalObject);
+    {
+        HeapIterationScope iterationScope(m_vm.heap);
+        m_vm.heap.objectSpace().forEachLiveCell(iterationScope, gatherSourceProviders);
+    }
+    for (auto* sourceProvider : gatherSourceProviders.sourceProviders)
+        sourceParsed(globalObject->globalExec(), sourceProvider, -1, String());
 }
 
 void Debugger::detach(JSGlobalObject* globalObject, ReasonForDetach reason)
@@ -195,8 +178,11 @@ void Debugger::detach(JSGlobalObject* globalObject, ReasonForDetach reason)
         clearDebuggerRequests(globalObject);
 
     globalObject->setDebugger(0);
-    if (!m_globalObjects.size())
-        m_vm = nullptr;
+}
+
+bool Debugger::isAttached(JSGlobalObject* globalObject)
+{
+    return globalObject->debugger() == this;
 }
 
 class Debugger::SetSteppingModeFunctor {
@@ -227,12 +213,12 @@ void Debugger::setSteppingMode(SteppingMode mode)
 {
     if (mode == m_steppingMode)
         return;
-    m_steppingMode = mode;
 
-    if (!m_vm)
-        return;
+    m_vm.heap.completeAllDFGPlans();
+
+    m_steppingMode = mode;
     SetSteppingModeFunctor functor(this, mode);
-    m_vm->heap.forEachCodeBlock(functor);
+    m_vm.heap.forEachCodeBlock(functor);
 }
 
 void Debugger::registerCodeBlock(CodeBlock* codeBlock)
@@ -242,9 +228,27 @@ void Debugger::registerCodeBlock(CodeBlock* codeBlock)
         codeBlock->setSteppingMode(CodeBlock::SteppingModeEnabled);
 }
 
+void Debugger::setProfilingClient(ProfilingClient* client)
+{
+    ASSERT(!!m_profilingClient != !!client);
+    m_profilingClient = client;
+
+    recompileAllJSFunctions();
+}
+
+double Debugger::willEvaluateScript()
+{
+    return m_profilingClient->willEvaluateScript();
+}
+
+void Debugger::didEvaluateScript(double startTime, ProfilingReason reason)
+{
+    m_profilingClient->didEvaluateScript(startTime, reason);
+}
+
 void Debugger::toggleBreakpoint(CodeBlock* codeBlock, Breakpoint& breakpoint, BreakpointState enabledOrNot)
 {
-    ScriptExecutable* executable = codeBlock->ownerExecutable();
+    ScriptExecutable* executable = codeBlock->ownerScriptExecutable();
 
     SourceID sourceID = static_cast<SourceID>(executable->sourceID());
     if (breakpoint.sourceID != sourceID)
@@ -253,7 +257,7 @@ void Debugger::toggleBreakpoint(CodeBlock* codeBlock, Breakpoint& breakpoint, Br
     unsigned line = breakpoint.line;
     unsigned column = breakpoint.column;
 
-    unsigned startLine = executable->lineNo();
+    unsigned startLine = executable->firstLine();
     unsigned startColumn = executable->startColumn();
     unsigned endLine = executable->lastLine();
     unsigned endColumn = executable->endColumn();
@@ -313,26 +317,15 @@ private:
 
 void Debugger::toggleBreakpoint(Breakpoint& breakpoint, Debugger::BreakpointState enabledOrNot)
 {
-    if (!m_vm)
-        return;
+    m_vm.heap.completeAllDFGPlans();
+
     ToggleBreakpointFunctor functor(this, breakpoint, enabledOrNot);
-    m_vm->heap.forEachCodeBlock(functor);
+    m_vm.heap.forEachCodeBlock(functor);
 }
 
-void Debugger::recompileAllJSFunctions(VM* vm)
+void Debugger::recompileAllJSFunctions()
 {
-    // If JavaScript is running, it's not safe to recompile, since we'll end
-    // up throwing away code that is live on the stack.
-    if (vm->entryScope) {
-        vm->entryScope->setRecompilationNeeded(true);
-        return;
-    }
-
-    vm->prepareToDiscardCode();
-
-    Recompiler recompiler(this);
-    HeapIterationScope iterationScope(vm->heap);
-    vm->heap.objectSpace().forEachLiveCell(iterationScope, recompiler);
+    m_vm.deleteAllCode();
 }
 
 BreakpointID Debugger::setBreakpoint(Breakpoint breakpoint, unsigned& actualLine, unsigned& actualColumn)
@@ -346,18 +339,18 @@ BreakpointID Debugger::setBreakpoint(Breakpoint breakpoint, unsigned& actualLine
         it = m_sourceIDToBreakpoints.set(sourceID, LineToBreakpointsMap()).iterator;
     LineToBreakpointsMap::iterator breaksIt = it->value.find(line);
     if (breaksIt == it->value.end())
-        breaksIt = it->value.set(line, BreakpointsInLine()).iterator;
+        breaksIt = it->value.set(line, adoptRef(new BreakpointsList)).iterator;
 
-    BreakpointsInLine& breakpoints = breaksIt->value;
-    unsigned breakpointsCount = breakpoints.size();
-    for (unsigned i = 0; i < breakpointsCount; i++)
-        if (breakpoints[i].column == column) {
+    BreakpointsList& breakpoints = *breaksIt->value;
+    for (Breakpoint* current = breakpoints.head(); current; current = current->next()) {
+        if (current->column == column) {
             // The breakpoint already exists. We're not allowed to create a new
             // breakpoint at this location. Rather than returning the breakpointID
             // of the pre-existing breakpoint, we need to return noBreakpointID
             // to indicate that we're not creating a new one.
             return noBreakpointID;
         }
+    }
 
     BreakpointID id = ++m_topBreakpointID;
     RELEASE_ASSERT(id != noBreakpointID);
@@ -366,8 +359,9 @@ BreakpointID Debugger::setBreakpoint(Breakpoint breakpoint, unsigned& actualLine
     actualLine = line;
     actualColumn = column;
 
-    breakpoints.append(breakpoint);
-    m_breakpointIDToBreakpoint.set(id, &breakpoints.last());
+    Breakpoint* newBreakpoint = new Breakpoint(breakpoint);
+    breakpoints.append(newBreakpoint);
+    m_breakpointIDToBreakpoint.set(id, newBreakpoint);
 
     toggleBreakpoint(breakpoint, BreakpointEnabled);
 
@@ -380,31 +374,35 @@ void Debugger::removeBreakpoint(BreakpointID id)
 
     BreakpointIDToBreakpointMap::iterator idIt = m_breakpointIDToBreakpoint.find(id);
     ASSERT(idIt != m_breakpointIDToBreakpoint.end());
-    Breakpoint& breakpoint = *idIt->value;
+    Breakpoint* breakpoint = idIt->value;
 
-    SourceID sourceID = breakpoint.sourceID;
+    SourceID sourceID = breakpoint->sourceID;
     ASSERT(sourceID);
     SourceIDToBreakpointsMap::iterator it = m_sourceIDToBreakpoints.find(sourceID);
     ASSERT(it != m_sourceIDToBreakpoints.end());
-    LineToBreakpointsMap::iterator breaksIt = it->value.find(breakpoint.line);
+    LineToBreakpointsMap::iterator breaksIt = it->value.find(breakpoint->line);
     ASSERT(breaksIt != it->value.end());
 
-    toggleBreakpoint(breakpoint, BreakpointDisabled);
+    toggleBreakpoint(*breakpoint, BreakpointDisabled);
 
-    BreakpointsInLine& breakpoints = breaksIt->value;
-    unsigned breakpointsCount = breakpoints.size();
-    for (unsigned i = 0; i < breakpointsCount; i++) {
-        if (breakpoints[i].id == breakpoint.id) {
-            breakpoints.remove(i);
-            m_breakpointIDToBreakpoint.remove(idIt);
+    BreakpointsList& breakpoints = *breaksIt->value;
+#if !ASSERT_DISABLED
+    bool found = false;
+    for (Breakpoint* current = breakpoints.head(); current && !found; current = current->next()) {
+        if (current->id == breakpoint->id)
+            found = true;
+    }
+    ASSERT(found);
+#endif
 
-            if (breakpoints.isEmpty()) {
-                it->value.remove(breaksIt);
-                if (it->value.isEmpty())
-                    m_sourceIDToBreakpoints.remove(it);
-            }
-            break;
-        }
+    m_breakpointIDToBreakpoint.remove(idIt);
+    breakpoints.remove(breakpoint);
+    delete breakpoint;
+
+    if (breakpoints.isEmpty()) {
+        it->value.remove(breaksIt);
+        if (it->value.isEmpty())
+            m_sourceIDToBreakpoints.remove(it);
     }
 }
 
@@ -425,12 +423,11 @@ bool Debugger::hasBreakpoint(SourceID sourceID, const TextPosition& position, Br
         return false;
 
     bool hit = false;
-    const BreakpointsInLine& breakpoints = breaksIt->value;
-    unsigned breakpointsCount = breakpoints.size();
-    unsigned i;
-    for (i = 0; i < breakpointsCount; i++) {
-        unsigned breakLine = breakpoints[i].line;
-        unsigned breakColumn = breakpoints[i].column;
+    const BreakpointsList& breakpoints = *breaksIt->value;
+    Breakpoint* breakpoint;
+    for (breakpoint = breakpoints.head(); breakpoint; breakpoint = breakpoint->next()) {
+        unsigned breakLine = breakpoint->line;
+        unsigned breakColumn = breakpoint->column;
         // Since frontend truncates the indent, the first statement in a line must match the breakpoint (line,0).
         ASSERT(this == m_currentCallFrame->codeBlock()->globalObject()->debugger());
         if ((line != m_lastExecutedLine && line == breakLine && !breakColumn)
@@ -443,17 +440,22 @@ bool Debugger::hasBreakpoint(SourceID sourceID, const TextPosition& position, Br
         return false;
 
     if (hitBreakpoint)
-        *hitBreakpoint = breakpoints[i];
+        *hitBreakpoint = *breakpoint;
 
-    if (breakpoints[i].condition.isEmpty())
+    breakpoint->hitCount++;
+    if (breakpoint->ignoreCount >= breakpoint->hitCount)
+        return false;
+
+    if (breakpoint->condition.isEmpty())
         return true;
 
     // We cannot stop in the debugger while executing condition code,
     // so make it looks like the debugger is already paused.
     TemporaryPausedState pausedState(*this);
 
-    JSValue exception;
-    JSValue result = DebuggerCallFrame::evaluateWithCallFrame(m_currentCallFrame, breakpoints[i].condition, exception);
+    NakedPtr<Exception> exception;
+    DebuggerCallFrame* debuggerCallFrame = currentDebuggerCallFrame();
+    JSValue result = debuggerCallFrame->evaluate(breakpoint->condition, exception);
 
     // We can lose the debugger while executing JavaScript.
     if (!m_currentCallFrame)
@@ -488,14 +490,14 @@ private:
 
 void Debugger::clearBreakpoints()
 {
+    m_vm.heap.completeAllDFGPlans();
+
     m_topBreakpointID = noBreakpointID;
     m_breakpointIDToBreakpoint.clear();
     m_sourceIDToBreakpoints.clear();
 
-    if (!m_vm)
-        return;
     ClearCodeBlockDebuggerRequestsFunctor functor(this);
-    m_vm->heap.forEachCodeBlock(functor);
+    m_vm.heap.forEachCodeBlock(functor);
 }
 
 class Debugger::ClearDebuggerRequestsFunctor {
@@ -518,9 +520,10 @@ private:
 
 void Debugger::clearDebuggerRequests(JSGlobalObject* globalObject)
 {
-    ASSERT(m_vm);
+    m_vm.heap.completeAllDFGPlans();
+
     ClearDebuggerRequestsFunctor functor(globalObject);
-    m_vm->heap.forEachCodeBlock(functor);
+    m_vm.heap.forEachCodeBlock(functor);
 }
 
 void Debugger::setBreakpointsActivated(bool activated)
@@ -545,10 +548,12 @@ void Debugger::breakProgram()
     if (m_isPaused)
         return;
 
+    if (!m_vm.topCallFrame)
+        return;
+
     m_pauseOnNextStatement = true;
     setSteppingMode(SteppingModeEnabled);
-    m_currentCallFrame = m_vm->topCallFrame;
-    ASSERT(m_currentCallFrame);
+    m_currentCallFrame = m_vm.topCallFrame;
     pauseIfNeeded(m_currentCallFrame);
 }
 
@@ -585,7 +590,8 @@ void Debugger::stepOutOfFunction()
     if (!m_isPaused)
         return;
 
-    m_pauseOnCallFrame = m_currentCallFrame ? m_currentCallFrame->callerFrameSkippingVMEntrySentinel() : 0;
+    VMEntryFrame* topVMEntryFrame = m_vm.topVMEntryFrame;
+    m_pauseOnCallFrame = m_currentCallFrame ? m_currentCallFrame->callerFrame(topVMEntryFrame) : 0;
     notifyDoneProcessingDebuggerEvents();
 }
 
@@ -612,6 +618,9 @@ void Debugger::pauseIfNeeded(CallFrame* callFrame)
     if (m_isPaused)
         return;
 
+    if (m_suppressAllPauses)
+        return;
+
     JSGlobalObject* vmEntryGlobalObject = callFrame->vmEntryGlobalObject();
     if (!needPauseHandling(vmEntryGlobalObject))
         return;
@@ -621,6 +630,8 @@ void Debugger::pauseIfNeeded(CallFrame* callFrame)
     bool pauseNow = m_pauseOnNextStatement;
     pauseNow |= (m_pauseOnCallFrame == m_currentCallFrame);
 
+    DebuggerPausedScope debuggerPausedScope(*this);
+
     intptr_t sourceID = DebuggerCallFrame::sourceIDForCallFrame(m_currentCallFrame);
     TextPosition position = DebuggerCallFrame::positionForCallFrame(m_currentCallFrame);
     pauseNow |= didHitBreakpoint = hasBreakpoint(sourceID, position, &breakpoint);
@@ -628,8 +639,6 @@ void Debugger::pauseIfNeeded(CallFrame* callFrame)
     if (!pauseNow)
         return;
 
-    DebuggerCallFrameScope debuggerCallFrameScope(*this);
-
     // Make sure we are not going to pause again on breakpoint actions by
     // reseting the pause state before executing any breakpoint actions.
     TemporaryPausedState pausedState(*this);
@@ -637,14 +646,21 @@ void Debugger::pauseIfNeeded(CallFrame* callFrame)
     m_pauseOnNextStatement = false;
 
     if (didHitBreakpoint) {
-        handleBreakpointHit(breakpoint);
+        handleBreakpointHit(vmEntryGlobalObject, breakpoint);
         // Note that the actions can potentially stop the debugger, so we need to check that
         // we still have a current call frame when we get back.
         if (breakpoint.autoContinue || !m_currentCallFrame)
             return;
+        m_pausingBreakpointID = breakpoint.id;
+    }
+
+    {
+        PauseReasonDeclaration reason(*this, didHitBreakpoint ? PausedForBreakpoint : m_reasonForPause);
+        handlePause(vmEntryGlobalObject, m_reasonForPause);
+        RELEASE_ASSERT(!callFrame->hadException());
     }
 
-    handlePause(m_reasonForPause, vmEntryGlobalObject);
+    m_pausingBreakpointID = noBreakpointID;
 
     if (!m_pauseOnNextStatement && !m_pauseOnCallFrame) {
         setSteppingMode(SteppingModeDisabled);
@@ -652,13 +668,13 @@ void Debugger::pauseIfNeeded(CallFrame* callFrame)
     }
 }
 
-void Debugger::exception(CallFrame* callFrame, JSValue exception, bool hasHandler)
+void Debugger::exception(CallFrame* callFrame, JSValue exception, bool hasCatchHandler)
 {
     if (m_isPaused)
         return;
 
     PauseReasonDeclaration reason(*this, PausedForException);
-    if (m_pauseOnExceptionsState == PauseOnAllExceptions || (m_pauseOnExceptionsState == PauseOnUncaughtExceptions && !hasHandler)) {
+    if (m_pauseOnExceptionsState == PauseOnAllExceptions || (m_pauseOnExceptionsState == PauseOnUncaughtExceptions && !hasCatchHandler)) {
         m_pauseOnNextStatement = true;
         setSteppingMode(SteppingModeEnabled);
     }
@@ -701,10 +717,13 @@ void Debugger::returnEvent(CallFrame* callFrame)
         return;
 
     // Treat stepping over a return statement like stepping out.
-    if (m_currentCallFrame == m_pauseOnCallFrame)
-        m_pauseOnCallFrame = m_currentCallFrame->callerFrameSkippingVMEntrySentinel();
+    if (m_currentCallFrame == m_pauseOnCallFrame) {
+        VMEntryFrame* topVMEntryFrame = m_vm.topVMEntryFrame;
+        m_pauseOnCallFrame = m_currentCallFrame->callerFrame(topVMEntryFrame);
+    }
 
-    m_currentCallFrame = m_currentCallFrame->callerFrameSkippingVMEntrySentinel();
+    VMEntryFrame* topVMEntryFrame = m_vm.topVMEntryFrame;
+    m_currentCallFrame = m_currentCallFrame->callerFrame(topVMEntryFrame);
 }
 
 void Debugger::willExecuteProgram(CallFrame* callFrame)
@@ -713,13 +732,7 @@ void Debugger::willExecuteProgram(CallFrame* callFrame)
         return;
 
     PauseReasonDeclaration reason(*this, PausedAtStartOfProgram);
-    // FIXME: This check for whether we're debugging a worker thread is a workaround
-    // for https://bugs.webkit.org/show_bug.cgi?id=102637. Remove it when we rework
-    // the debugger implementation to not require callbacks.
-    if (!m_isInWorkerThread)
-        updateCallFrameAndPauseIfNeeded(callFrame);
-    else if (isStepping())
-        updateCallFrame(callFrame);
+    updateCallFrameAndPauseIfNeeded(callFrame);
 }
 
 void Debugger::didExecuteProgram(CallFrame* callFrame)
@@ -734,11 +747,13 @@ void Debugger::didExecuteProgram(CallFrame* callFrame)
     if (!m_currentCallFrame)
         return;
     if (m_currentCallFrame == m_pauseOnCallFrame) {
-        m_pauseOnCallFrame = m_currentCallFrame->callerFrameSkippingVMEntrySentinel();
+        VMEntryFrame* topVMEntryFrame = m_vm.topVMEntryFrame;
+        m_pauseOnCallFrame = m_currentCallFrame->callerFrame(topVMEntryFrame);
         if (!m_currentCallFrame)
             return;
     }
-    m_currentCallFrame = m_currentCallFrame->callerFrameSkippingVMEntrySentinel();
+    VMEntryFrame* topVMEntryFrame = m_vm.topVMEntryFrame;
+    m_currentCallFrame = m_currentCallFrame->callerFrame(topVMEntryFrame);
 }
 
 void Debugger::didReachBreakpoint(CallFrame* callFrame)
@@ -746,7 +761,7 @@ void Debugger::didReachBreakpoint(CallFrame* callFrame)
     if (m_isPaused)
         return;
 
-    PauseReasonDeclaration reason(*this, PausedForBreakpoint);
+    PauseReasonDeclaration reason(*this, PausedForDebuggerStatement);
     m_pauseOnNextStatement = true;
     setSteppingMode(SteppingModeEnabled);
     updateCallFrameAndPauseIfNeeded(callFrame);
diff --git a/Source/JavaScriptCore/debugger/Debugger.h b/Source/JavaScriptCore/debugger/Debugger.h
index f7b734f37..2e91aafbe 100644
--- a/Source/JavaScriptCore/debugger/Debugger.h
+++ b/Source/JavaScriptCore/debugger/Debugger.h
@@ -23,17 +23,19 @@
 #define Debugger_h
 
 #include "Breakpoint.h"
+#include "CallData.h"
 #include "DebuggerCallFrame.h"
 #include "DebuggerPrimitives.h"
 #include "JSCJSValue.h"
 #include <wtf/HashMap.h>
 #include <wtf/HashSet.h>
 #include <wtf/RefPtr.h>
-#include <wtf/Vector.h>
 #include <wtf/text/TextPosition.h>
 
 namespace JSC {
 
+class CodeBlock;
+class Exception;
 class ExecState;
 class JSGlobalObject;
 class SourceProvider;
@@ -43,9 +45,11 @@ typedef ExecState CallFrame;
 
 class JS_EXPORT_PRIVATE Debugger {
 public:
-    Debugger(bool isInWorkerThread = false);
+    Debugger(VM&);
     virtual ~Debugger();
 
+    VM& vm() { return m_vm; }
+
     JSC::DebuggerCallFrame* currentDebuggerCallFrame() const;
     bool hasHandlerForExceptionCallback() const
     {
@@ -60,12 +64,13 @@ public:
 
     bool needsExceptionCallbacks() const { return m_pauseOnExceptionsState != DontPauseOnExceptions; }
 
-    void attach(JSGlobalObject*);
     enum ReasonForDetach {
         TerminatingDebuggingSession,
         GlobalObjectIsDestructing
     };
-    virtual void detach(JSGlobalObject*, ReasonForDetach);
+    void attach(JSGlobalObject*);
+    void detach(JSGlobalObject*, ReasonForDetach);
+    bool isAttached(JSGlobalObject*);
 
     BreakpointID setBreakpoint(Breakpoint, unsigned& actualLine, unsigned& actualColumn);
     void removeBreakpoint(BreakpointID);
@@ -82,6 +87,20 @@ public:
     PauseOnExceptionsState pauseOnExceptionsState() const { return m_pauseOnExceptionsState; }
     void setPauseOnExceptionsState(PauseOnExceptionsState);
 
+    enum ReasonForPause {
+        NotPaused,
+        PausedForException,
+        PausedAtStatement,
+        PausedAfterCall,
+        PausedBeforeReturn,
+        PausedAtStartOfProgram,
+        PausedAtEndOfProgram,
+        PausedForBreakpoint,
+        PausedForDebuggerStatement,
+    };
+    ReasonForPause reasonForPause() const { return m_reasonForPause; }
+    BreakpointID pausingBreakpointID() const { return m_pausingBreakpointID; }
+
     void setPauseOnNextStatement(bool);
     void breakProgram();
     void continueProgram();
@@ -89,12 +108,15 @@ public:
     void stepOverStatement();
     void stepOutOfFunction();
 
-    bool isPaused() { return m_isPaused; }
+    bool isPaused() const { return m_isPaused; }
     bool isStepping() const { return m_steppingMode == SteppingModeEnabled; }
 
+    bool suppressAllPauses() const { return m_suppressAllPauses; }
+    void setSuppressAllPauses(bool suppress) { m_suppressAllPauses = suppress; }
+
     virtual void sourceParsed(ExecState*, SourceProvider*, int errorLineNumber, const WTF::String& errorMessage) = 0;
 
-    void exception(CallFrame*, JSValue exceptionValue, bool hasHandler);
+    void exception(CallFrame*, JSValue exceptionValue, bool hasCatchHandler);
     void atStatement(CallFrame*);
     void callEvent(CallFrame*);
     void returnEvent(CallFrame*);
@@ -102,34 +124,35 @@ public:
     void didExecuteProgram(CallFrame*);
     void didReachBreakpoint(CallFrame*);
 
-    void recompileAllJSFunctions(VM*);
+    virtual void recompileAllJSFunctions();
 
     void registerCodeBlock(CodeBlock*);
 
-protected:
-    virtual bool needPauseHandling(JSGlobalObject*) { return false; }
-    virtual void handleBreakpointHit(const Breakpoint&) { }
-    virtual void handleExceptionInBreakpointCondition(ExecState*, JSValue exception) const { UNUSED_PARAM(exception); }
-
-    enum ReasonForPause {
-        NotPaused,
-        PausedForException,
-        PausedAtStatement,
-        PausedAfterCall,
-        PausedBeforeReturn,
-        PausedAtStartOfProgram,
-        PausedAtEndOfProgram,
-        PausedForBreakpoint
+    class ProfilingClient {
+    public:
+        virtual ~ProfilingClient() { }
+        virtual bool isAlreadyProfiling() const = 0;
+        virtual double willEvaluateScript() = 0;
+        virtual void didEvaluateScript(double startTime, ProfilingReason) = 0;
     };
 
-    virtual void handlePause(ReasonForPause, JSGlobalObject*) { }
+    void setProfilingClient(ProfilingClient*);
+    bool hasProfilingClient() const { return m_profilingClient != nullptr; }
+    bool isAlreadyProfiling() const { return m_profilingClient && m_profilingClient->isAlreadyProfiling(); }
+    double willEvaluateScript();
+    void didEvaluateScript(double startTime, ProfilingReason);
+
+protected:
+    virtual bool needPauseHandling(JSGlobalObject*) { return false; }
+    virtual void handleBreakpointHit(JSGlobalObject*, const Breakpoint&) { }
+    virtual void handleExceptionInBreakpointCondition(ExecState*, Exception*) const { }
+    virtual void handlePause(JSGlobalObject*, ReasonForPause) { }
     virtual void notifyDoneProcessingDebuggerEvents() { }
 
 private:
     typedef HashMap<BreakpointID, Breakpoint*> BreakpointIDToBreakpointMap;
 
-    typedef Vector<Breakpoint> BreakpointsInLine;
-    typedef HashMap<unsigned, BreakpointsInLine, WTF::IntHash<int>, WTF::UnsignedWithZeroKeyHashTraits<int>> LineToBreakpointsMap;
+    typedef HashMap<unsigned, RefPtr<BreakpointsList>, WTF::IntHash<int>, WTF::UnsignedWithZeroKeyHashTraits<int>> LineToBreakpointsMap;
     typedef HashMap<SourceID, LineToBreakpointsMap, WTF::IntHash<SourceID>, WTF::UnsignedWithZeroKeyHashTraits<SourceID>> SourceIDToBreakpointsMap;
 
     class ClearCodeBlockDebuggerRequestsFunctor;
@@ -182,7 +205,7 @@ private:
 
     void clearDebuggerRequests(JSGlobalObject*);
 
-    VM* m_vm;
+    VM& m_vm;
     HashSet<JSGlobalObject*> m_globalObjects;
 
     PauseOnExceptionsState m_pauseOnExceptionsState;
@@ -190,8 +213,8 @@ private:
     bool m_isPaused : 1;
     bool m_breakpointsActivated : 1;
     bool m_hasHandlerForExceptionCallback : 1;
-    bool m_isInWorkerThread : 1;
-    SteppingMode m_steppingMode : 1;
+    bool m_suppressAllPauses : 1;
+    unsigned m_steppingMode : 1; // SteppingMode
 
     ReasonForPause m_reasonForPause;
     JSValue m_currentException;
@@ -201,12 +224,15 @@ private:
     SourceID m_lastExecutedSourceID;
 
     BreakpointID m_topBreakpointID;
+    BreakpointID m_pausingBreakpointID;
     BreakpointIDToBreakpointMap m_breakpointIDToBreakpoint;
     SourceIDToBreakpointsMap m_sourceIDToBreakpoints;
 
     RefPtr<JSC::DebuggerCallFrame> m_currentDebuggerCallFrame;
 
-    friend class DebuggerCallFrameScope;
+    ProfilingClient* m_profilingClient { nullptr };
+
+    friend class DebuggerPausedScope;
     friend class TemporaryPausedState;
     friend class LLIntOffsetsExtractor;
 };
diff --git a/Source/JavaScriptCore/debugger/DebuggerActivation.cpp b/Source/JavaScriptCore/debugger/DebuggerActivation.cpp
deleted file mode 100644
index 75b08ea81..000000000
--- a/Source/JavaScriptCore/debugger/DebuggerActivation.cpp
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
- */
-
-#include "config.h"
-#include "DebuggerActivation.h"
-
-#include "JSActivation.h"
-#include "Operations.h"
-
-namespace JSC {
-
-STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(DebuggerActivation);
-
-const ClassInfo DebuggerActivation::s_info = { "DebuggerActivation", &Base::s_info, 0, 0, CREATE_METHOD_TABLE(DebuggerActivation) };
-
-DebuggerActivation::DebuggerActivation(VM& vm)
-    : JSNonFinalObject(vm, vm.debuggerActivationStructure.get())
-{
-}
-
-void DebuggerActivation::finishCreation(VM& vm, JSObject* activation)
-{
-    Base::finishCreation(vm);
-    ASSERT(activation);
-    ASSERT(activation->isActivationObject());
-    m_activation.set(vm, this, jsCast<JSActivation*>(activation));
-}
-
-void DebuggerActivation::visitChildren(JSCell* cell, SlotVisitor& visitor)
-{
-    DebuggerActivation* thisObject = jsCast<DebuggerActivation*>(cell);
-    ASSERT_GC_OBJECT_INHERITS(thisObject, info());
-    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
-    ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
-
-    JSObject::visitChildren(thisObject, visitor);
-    visitor.append(&thisObject->m_activation);
-}
-
-String DebuggerActivation::className(const JSObject* object)
-{
-    const DebuggerActivation* thisObject = jsCast<const DebuggerActivation*>(object);
-    return thisObject->m_activation->methodTable()->className(thisObject->m_activation.get());
-}
-
-bool DebuggerActivation::getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
-{
-    DebuggerActivation* thisObject = jsCast<DebuggerActivation*>(object);
-    return thisObject->m_activation->methodTable()->getOwnPropertySlot(thisObject->m_activation.get(), exec, propertyName, slot);
-}
-
-void DebuggerActivation::put(JSCell* cell, ExecState* exec, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
-{
-    DebuggerActivation* thisObject = jsCast<DebuggerActivation*>(cell);
-    thisObject->m_activation->methodTable()->put(thisObject->m_activation.get(), exec, propertyName, value, slot);
-}
-
-bool DebuggerActivation::deleteProperty(JSCell* cell, ExecState* exec, PropertyName propertyName)
-{
-    DebuggerActivation* thisObject = jsCast<DebuggerActivation*>(cell);
-    return thisObject->m_activation->methodTable()->deleteProperty(thisObject->m_activation.get(), exec, propertyName);
-}
-
-void DebuggerActivation::getOwnPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
-{
-    DebuggerActivation* thisObject = jsCast<DebuggerActivation*>(object);
-    thisObject->m_activation->methodTable()->getPropertyNames(thisObject->m_activation.get(), exec, propertyNames, mode);
-}
-
-bool DebuggerActivation::defineOwnProperty(JSObject* object, ExecState* exec, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
-{
-    DebuggerActivation* thisObject = jsCast<DebuggerActivation*>(object);
-    return thisObject->m_activation->methodTable()->defineOwnProperty(thisObject->m_activation.get(), exec, propertyName, descriptor, shouldThrow);
-}
-
-} // namespace JSC
diff --git a/Source/JavaScriptCore/debugger/DebuggerActivation.h b/Source/JavaScriptCore/debugger/DebuggerActivation.h
deleted file mode 100644
index e90383eaa..000000000
--- a/Source/JavaScriptCore/debugger/DebuggerActivation.h
+++ /dev/null
@@ -1,71 +0,0 @@
-/*
- * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
- */
-
-#ifndef DebuggerActivation_h
-#define DebuggerActivation_h
-
-#include "JSObject.h"
-
-namespace JSC {
-
-class DebuggerActivation : public JSNonFinalObject {
-public:
-    typedef JSNonFinalObject Base;
-
-    static DebuggerActivation* create(VM& vm, JSObject* object)
-    {
-        DebuggerActivation* activation = new (NotNull, allocateCell<DebuggerActivation>(vm.heap)) DebuggerActivation(vm);
-        activation->finishCreation(vm, object);
-        return activation;
-    }
-
-    static void visitChildren(JSCell*, SlotVisitor&);
-    static String className(const JSObject*);
-    static bool getOwnPropertySlot(JSObject*, ExecState*, PropertyName, PropertySlot&);
-    static void put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
-    static bool deleteProperty(JSCell*, ExecState*, PropertyName);
-    static void getOwnPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
-    static bool defineOwnProperty(JSObject*, ExecState*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
-
-    DECLARE_EXPORT_INFO;
-
-    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype) 
-    {
-        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info()); 
-    }
-
-protected:
-    static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesVisitChildren | JSObject::StructureFlags;
-
-    JS_EXPORT_PRIVATE void finishCreation(VM&, JSObject* activation);
-
-private:
-    JS_EXPORT_PRIVATE DebuggerActivation(VM&);
-    WriteBarrier<JSActivation> m_activation;
-};
-
-} // namespace JSC
-
-#endif // DebuggerActivation_h
diff --git a/Source/JavaScriptCore/debugger/DebuggerCallFrame.cpp b/Source/JavaScriptCore/debugger/DebuggerCallFrame.cpp
index 90cee8c23..f4794fd45 100644
--- a/Source/JavaScriptCore/debugger/DebuggerCallFrame.cpp
+++ b/Source/JavaScriptCore/debugger/DebuggerCallFrame.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2013, 2014 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -10,7 +10,7 @@
  * 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 Computer, Inc. ("Apple") nor the names of
+ * 3.  Neither the name of Apple 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.
  *
@@ -29,13 +29,16 @@
 #include "config.h"
 #include "DebuggerCallFrame.h"
 
-#include "JSFunction.h"
 #include "CodeBlock.h"
+#include "DebuggerEvalEnabler.h"
+#include "DebuggerScope.h"
 #include "Interpreter.h"
-#include "Operations.h"
+#include "JSFunction.h"
+#include "JSLexicalEnvironment.h"
+#include "JSCInlines.h"
 #include "Parser.h"
 #include "StackVisitor.h"
-#include "VMEntryScope.h"
+#include "StrongInlines.h"
 
 namespace JSC {
 
@@ -55,13 +58,36 @@ private:
     unsigned m_column;
 };
 
+class FindCallerMidStackFunctor {
+public:
+    FindCallerMidStackFunctor(CallFrame* callFrame)
+        : m_callFrame(callFrame)
+        , m_callerFrame(nullptr)
+    { }
+
+    StackVisitor::Status operator()(StackVisitor& visitor)
+    {
+        if (visitor->callFrame() == m_callFrame) {
+            m_callerFrame = visitor->callerFrame();
+            return StackVisitor::Done;
+        }
+        return StackVisitor::Continue;
+    }
+
+    CallFrame* getCallerFrame() const { return m_callerFrame; }
+
+private:
+    CallFrame* m_callFrame;
+    CallFrame* m_callerFrame;
+};
+
 DebuggerCallFrame::DebuggerCallFrame(CallFrame* callFrame)
     : m_callFrame(callFrame)
 {
     m_position = positionForCallFrame(m_callFrame);
 }
 
-PassRefPtr<DebuggerCallFrame> DebuggerCallFrame::callerFrame()
+RefPtr<DebuggerCallFrame> DebuggerCallFrame::callerFrame()
 {
     ASSERT(isValid());
     if (!isValid())
@@ -70,9 +96,12 @@ PassRefPtr<DebuggerCallFrame> DebuggerCallFrame::callerFrame()
     if (m_caller)
         return m_caller;
 
-    CallFrame* callerFrame = m_callFrame->callerFrameSkippingVMEntrySentinel();
+    FindCallerMidStackFunctor functor(m_callFrame);
+    m_callFrame->vm().topCallFrame->iterate(functor);
+
+    CallFrame* callerFrame = functor.getCallerFrame();
     if (!callerFrame)
-        return 0;
+        return nullptr;
 
     m_caller = DebuggerCallFrame::create(callerFrame);
     return m_caller;
@@ -99,19 +128,29 @@ String DebuggerCallFrame::functionName() const
     ASSERT(isValid());
     if (!isValid())
         return String();
-    JSObject* function = m_callFrame->callee();
-    if (!function)
-        return String();
-
-    return getCalculatedDisplayName(m_callFrame, function);
+    return m_callFrame->friendlyFunctionName();
 }
 
-JSScope* DebuggerCallFrame::scope() const
+DebuggerScope* DebuggerCallFrame::scope()
 {
     ASSERT(isValid());
     if (!isValid())
         return 0;
-    return m_callFrame->scope();
+
+    if (!m_scope) {
+        VM& vm = m_callFrame->vm();
+        JSScope* scope;
+        CodeBlock* codeBlock = m_callFrame->codeBlock();
+        if (codeBlock && codeBlock->scopeRegister().isValid())
+            scope = m_callFrame->scope(codeBlock->scopeRegister().offset());
+        else if (JSCallee* callee = jsDynamicCast<JSCallee*>(m_callFrame->callee()))
+            scope = callee->scope();
+        else
+            scope = m_callFrame->lexicalGlobalObject();
+
+        m_scope.set(vm, DebuggerScope::create(vm, scope));
+    }
+    return m_scope.get();
 }
 
 DebuggerCallFrame::Type DebuggerCallFrame::type() const
@@ -120,7 +159,7 @@ DebuggerCallFrame::Type DebuggerCallFrame::type() const
     if (!isValid())
         return ProgramType;
 
-    if (m_callFrame->callee())
+    if (jsDynamicCast<JSFunction*>(m_callFrame->callee()))
         return FunctionType;
 
     return ProgramType;
@@ -133,14 +172,10 @@ JSValue DebuggerCallFrame::thisValue() const
 }
 
 // Evaluate some JavaScript code in the scope of this frame.
-JSValue DebuggerCallFrame::evaluate(const String& script, JSValue& exception) const
+JSValue DebuggerCallFrame::evaluate(const String& script, NakedPtr<Exception>& exception)
 {
     ASSERT(isValid());
-    return evaluateWithCallFrame(m_callFrame, script, exception);
-}
-
-JSValue DebuggerCallFrame::evaluateWithCallFrame(CallFrame* callFrame, const String& script, JSValue& exception)
-{
+    CallFrame* callFrame = m_callFrame;
     if (!callFrame)
         return jsNull();
 
@@ -149,8 +184,15 @@ JSValue DebuggerCallFrame::evaluateWithCallFrame(CallFrame* callFrame, const Str
     if (!callFrame->codeBlock())
         return JSValue();
     
+    DebuggerEvalEnabler evalEnabler(callFrame);
     VM& vm = callFrame->vm();
-    EvalExecutable* eval = EvalExecutable::create(callFrame, makeSource(script), callFrame->codeBlock()->isStrictMode());
+    auto& codeBlock = *callFrame->codeBlock();
+    ThisTDZMode thisTDZMode = codeBlock.unlinkedCodeBlock()->constructorKind() == ConstructorKind::Derived ? ThisTDZMode::AlwaysCheck : ThisTDZMode::CheckIfNeeded;
+
+    VariableEnvironment variablesUnderTDZ;
+    JSScope::collectVariablesUnderTDZ(scope()->jsScope(), variablesUnderTDZ);
+
+    EvalExecutable* eval = EvalExecutable::create(callFrame, makeSource(script), codeBlock.isStrictMode(), thisTDZMode, codeBlock.unlinkedCodeBlock()->derivedContextType(), codeBlock.unlinkedCodeBlock()->isArrowFunction(), &variablesUnderTDZ);
     if (vm.exception()) {
         exception = vm.exception();
         vm.clearException();
@@ -158,7 +200,7 @@ JSValue DebuggerCallFrame::evaluateWithCallFrame(CallFrame* callFrame, const Str
     }
 
     JSValue thisValue = thisValueForCallFrame(callFrame);
-    JSValue result = vm.interpreter->execute(eval, callFrame, thisValue, callFrame->scope());
+    JSValue result = vm.interpreter->execute(eval, callFrame, thisValue, scope()->jsScope());
     if (vm.exception()) {
         exception = vm.exception();
         vm.clearException();
@@ -169,10 +211,13 @@ JSValue DebuggerCallFrame::evaluateWithCallFrame(CallFrame* callFrame, const Str
 
 void DebuggerCallFrame::invalidate()
 {
-    m_callFrame = nullptr;
-    RefPtr<DebuggerCallFrame> frame = m_caller.release();
+    RefPtr<DebuggerCallFrame> frame = this;
     while (frame) {
         frame->m_callFrame = nullptr;
+        if (frame->m_scope) {
+            frame->m_scope->invalidateChain();
+            frame->m_scope.clear();
+        }
         frame = frame->m_caller.release();
     }
 }
@@ -193,7 +238,7 @@ SourceID DebuggerCallFrame::sourceIDForCallFrame(CallFrame* callFrame)
     CodeBlock* codeBlock = callFrame->codeBlock();
     if (!codeBlock)
         return noSourceID;
-    return codeBlock->ownerExecutable()->sourceID();
+    return codeBlock->ownerScriptExecutable()->sourceID();
 }
 
 JSValue DebuggerCallFrame::thisValueForCallFrame(CallFrame* callFrame)
diff --git a/Source/JavaScriptCore/debugger/DebuggerCallFrame.h b/Source/JavaScriptCore/debugger/DebuggerCallFrame.h
index 09c3fb9d8..aa3cca52b 100644
--- a/Source/JavaScriptCore/debugger/DebuggerCallFrame.h
+++ b/Source/JavaScriptCore/debugger/DebuggerCallFrame.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2013, 2014 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -10,7 +10,7 @@
  * 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 Computer, Inc. ("Apple") nor the names of
+ * 3.  Neither the name of Apple 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.
  *
@@ -29,26 +29,32 @@
 #ifndef DebuggerCallFrame_h
 #define DebuggerCallFrame_h
 
-#include "CallFrame.h"
 #include "DebuggerPrimitives.h"
+#include "Strong.h"
+#include <wtf/NakedPtr.h>
 #include <wtf/PassRefPtr.h>
 #include <wtf/RefCounted.h>
 #include <wtf/text/TextPosition.h>
 
 namespace JSC {
 
+class DebuggerScope;
+class Exception;
+class ExecState;
+typedef ExecState CallFrame;
+
 class DebuggerCallFrame : public RefCounted<DebuggerCallFrame> {
 public:
     enum Type { ProgramType, FunctionType };
 
-    static PassRefPtr<DebuggerCallFrame> create(CallFrame* callFrame)
+    static Ref<DebuggerCallFrame> create(CallFrame* callFrame)
     {
-        return adoptRef(new DebuggerCallFrame(callFrame));
+        return adoptRef(*new DebuggerCallFrame(callFrame));
     }
 
     JS_EXPORT_PRIVATE explicit DebuggerCallFrame(CallFrame*);
 
-    JS_EXPORT_PRIVATE PassRefPtr<DebuggerCallFrame> callerFrame();
+    JS_EXPORT_PRIVATE RefPtr<DebuggerCallFrame> callerFrame();
     ExecState* exec() const { return m_callFrame; }
     JS_EXPORT_PRIVATE SourceID sourceID() const;
 
@@ -58,11 +64,11 @@ public:
     JS_EXPORT_PRIVATE const TextPosition& position() const { return m_position; }
 
     JS_EXPORT_PRIVATE JSGlobalObject* vmEntryGlobalObject() const;
-    JS_EXPORT_PRIVATE JSScope* scope() const;
+    JS_EXPORT_PRIVATE DebuggerScope* scope();
     JS_EXPORT_PRIVATE String functionName() const;
     JS_EXPORT_PRIVATE Type type() const;
     JS_EXPORT_PRIVATE JSValue thisValue() const;
-    JS_EXPORT_PRIVATE JSValue evaluate(const String&, JSValue& exception) const;
+    JSValue evaluate(const String&, NakedPtr<Exception>&);
 
     bool isValid() const { return !!m_callFrame; }
     JS_EXPORT_PRIVATE void invalidate();
@@ -70,7 +76,6 @@ public:
     // The following are only public for the Debugger's use only. They will be
     // made private soon. Other clients should not use these.
 
-    JS_EXPORT_PRIVATE static JSValue evaluateWithCallFrame(CallFrame*, const String& script, JSValue& exception);
     JS_EXPORT_PRIVATE static TextPosition positionForCallFrame(CallFrame*);
     JS_EXPORT_PRIVATE static SourceID sourceIDForCallFrame(CallFrame*);
     static JSValue thisValueForCallFrame(CallFrame*);
@@ -79,6 +84,9 @@ private:
     CallFrame* m_callFrame;
     RefPtr<DebuggerCallFrame> m_caller;
     TextPosition m_position;
+    // The DebuggerPausedScope is responsible for calling invalidate() which,
+    // in turn, will clear this strong ref.
+    Strong<DebuggerScope> m_scope;
 };
 
 } // namespace JSC
diff --git a/Source/JavaScriptCore/debugger/DebuggerEvalEnabler.h b/Source/JavaScriptCore/debugger/DebuggerEvalEnabler.h
new file mode 100644
index 000000000..bb75b1f15
--- /dev/null
+++ b/Source/JavaScriptCore/debugger/DebuggerEvalEnabler.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2014 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DebuggerEvalEnabler_h
+#define DebuggerEvalEnabler_h
+
+#include "CallFrame.h"
+#include "JSGlobalObject.h"
+
+namespace JSC {
+
+class DebuggerEvalEnabler {
+public:
+    explicit DebuggerEvalEnabler(const ExecState* exec)
+        : m_exec(exec)
+        , m_evalWasDisabled(false)
+    {
+        if (exec) {
+            JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+            m_evalWasDisabled = !globalObject->evalEnabled();
+            if (m_evalWasDisabled)
+                globalObject->setEvalEnabled(true, globalObject->evalDisabledErrorMessage());
+        }
+    }
+
+    ~DebuggerEvalEnabler()
+    {
+        if (m_evalWasDisabled) {
+            JSGlobalObject* globalObject = m_exec->lexicalGlobalObject();
+            globalObject->setEvalEnabled(false, globalObject->evalDisabledErrorMessage());
+        }
+    }
+
+private:
+    const ExecState* m_exec;
+    bool m_evalWasDisabled;
+};
+
+} // namespace JSC
+
+#endif // DebuggerEvalEnabler_h
diff --git a/Source/JavaScriptCore/debugger/DebuggerPrimitives.h b/Source/JavaScriptCore/debugger/DebuggerPrimitives.h
index 635a5bfe8..ab7301b5c 100644
--- a/Source/JavaScriptCore/debugger/DebuggerPrimitives.h
+++ b/Source/JavaScriptCore/debugger/DebuggerPrimitives.h
@@ -26,6 +26,8 @@
 #ifndef DebuggerPrimitives_h
 #define DebuggerPrimitives_h
 
+#include <stddef.h>
+
 namespace JSC {
 
 typedef size_t SourceID;
diff --git a/Source/JavaScriptCore/debugger/DebuggerScope.cpp b/Source/JavaScriptCore/debugger/DebuggerScope.cpp
new file mode 100644
index 000000000..c3efbd56d
--- /dev/null
+++ b/Source/JavaScriptCore/debugger/DebuggerScope.cpp
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2008-2009, 2014 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "DebuggerScope.h"
+
+#include "JSLexicalEnvironment.h"
+#include "JSCInlines.h"
+#include "JSWithScope.h"
+
+namespace JSC {
+
+STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(DebuggerScope);
+
+const ClassInfo DebuggerScope::s_info = { "DebuggerScope", &Base::s_info, 0, CREATE_METHOD_TABLE(DebuggerScope) };
+
+DebuggerScope::DebuggerScope(VM& vm, JSScope* scope)
+    : JSNonFinalObject(vm, scope->globalObject()->debuggerScopeStructure())
+{
+    ASSERT(scope);
+    m_scope.set(vm, this, scope);
+}
+
+void DebuggerScope::finishCreation(VM& vm)
+{
+    Base::finishCreation(vm);
+}
+
+void DebuggerScope::visitChildren(JSCell* cell, SlotVisitor& visitor)
+{
+    DebuggerScope* thisObject = jsCast<DebuggerScope*>(cell);
+    ASSERT_GC_OBJECT_INHERITS(thisObject, info());
+    JSObject::visitChildren(thisObject, visitor);
+    visitor.append(&thisObject->m_scope);
+    visitor.append(&thisObject->m_next);
+}
+
+String DebuggerScope::className(const JSObject* object)
+{
+    const DebuggerScope* scope = jsCast<const DebuggerScope*>(object);
+    ASSERT(scope->isValid());
+    if (!scope->isValid())
+        return String();
+    JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
+    return thisObject->methodTable()->className(thisObject);
+}
+
+bool DebuggerScope::getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
+{
+    DebuggerScope* scope = jsCast<DebuggerScope*>(object);
+    ASSERT(scope->isValid());
+    if (!scope->isValid())
+        return false;
+    JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
+    slot.setThisValue(JSValue(thisObject));
+
+    // By default, JSObject::getPropertySlot() will look in the DebuggerScope's prototype
+    // chain and not the wrapped scope, and JSObject::getPropertySlot() cannot be overridden
+    // to behave differently for the DebuggerScope.
+    //
+    // Instead, we'll treat all properties in the wrapped scope and its prototype chain as
+    // the own properties of the DebuggerScope. This is fine because the WebInspector
+    // does not presently need to distinguish between what's owned at each level in the
+    // prototype chain. Hence, we'll invoke getPropertySlot() on the wrapped scope here
+    // instead of getOwnPropertySlot().
+    bool result = thisObject->getPropertySlot(exec, propertyName, slot);
+    if (result && slot.isValue() && slot.getValue(exec, propertyName) == jsTDZValue()) {
+        // FIXME:
+        // We hit a scope property that has the TDZ empty value.
+        // Currently, we just lie to the inspector and claim that this property is undefined.
+        // This is not ideal and we should fix it.
+        // https://bugs.webkit.org/show_bug.cgi?id=144977
+        slot.setValue(slot.slotBase(), DontEnum, jsUndefined());
+        return true;
+    }
+    return result;
+}
+
+void DebuggerScope::put(JSCell* cell, ExecState* exec, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
+{
+    DebuggerScope* scope = jsCast<DebuggerScope*>(cell);
+    ASSERT(scope->isValid());
+    if (!scope->isValid())
+        return;
+    JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
+    slot.setThisValue(JSValue(thisObject));
+    thisObject->methodTable()->put(thisObject, exec, propertyName, value, slot);
+}
+
+bool DebuggerScope::deleteProperty(JSCell* cell, ExecState* exec, PropertyName propertyName)
+{
+    DebuggerScope* scope = jsCast<DebuggerScope*>(cell);
+    ASSERT(scope->isValid());
+    if (!scope->isValid())
+        return false;
+    JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
+    return thisObject->methodTable()->deleteProperty(thisObject, exec, propertyName);
+}
+
+void DebuggerScope::getOwnPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
+{
+    DebuggerScope* scope = jsCast<DebuggerScope*>(object);
+    ASSERT(scope->isValid());
+    if (!scope->isValid())
+        return;
+    JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
+    thisObject->methodTable()->getPropertyNames(thisObject, exec, propertyNames, mode);
+}
+
+bool DebuggerScope::defineOwnProperty(JSObject* object, ExecState* exec, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
+{
+    DebuggerScope* scope = jsCast<DebuggerScope*>(object);
+    ASSERT(scope->isValid());
+    if (!scope->isValid())
+        return false;
+    JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
+    return thisObject->methodTable()->defineOwnProperty(thisObject, exec, propertyName, descriptor, shouldThrow);
+}
+
+DebuggerScope* DebuggerScope::next()
+{
+    ASSERT(isValid());
+    if (!m_next && m_scope->next()) {
+        VM& vm = *m_scope->vm();
+        DebuggerScope* nextScope = create(vm, m_scope->next());
+        m_next.set(vm, this, nextScope);
+    }
+    return m_next.get();
+}
+
+void DebuggerScope::invalidateChain()
+{
+    if (!isValid())
+        return;
+
+    DebuggerScope* scope = this;
+    while (scope) {
+        DebuggerScope* nextScope = scope->m_next.get();
+        scope->m_next.clear();
+        scope->m_scope.clear(); // This also marks this scope as invalid.
+        scope = nextScope;
+    }
+}
+
+bool DebuggerScope::isCatchScope() const
+{
+    return m_scope->isCatchScope();
+}
+
+bool DebuggerScope::isFunctionNameScope() const
+{
+    return m_scope->isFunctionNameScopeObject();
+}
+
+bool DebuggerScope::isWithScope() const
+{
+    return m_scope->isWithScope();
+}
+
+bool DebuggerScope::isGlobalScope() const
+{
+    return m_scope->isGlobalObject();
+}
+
+bool DebuggerScope::isGlobalLexicalEnvironment() const
+{
+    return m_scope->isGlobalLexicalEnvironment();
+}
+
+bool DebuggerScope::isClosureScope() const
+{
+    // In the current debugger implementation, every function or eval will create an
+    // lexical environment object. Hence, a lexical environment object implies a
+    // function or eval scope.
+    return m_scope->isVarScope() || m_scope->isLexicalScope();
+}
+
+bool DebuggerScope::isNestedLexicalScope() const
+{
+    return m_scope->isNestedLexicalScope();
+}
+
+JSValue DebuggerScope::caughtValue(ExecState* exec) const
+{
+    ASSERT(isCatchScope());
+    JSLexicalEnvironment* catchEnvironment = jsCast<JSLexicalEnvironment*>(m_scope.get());
+    SymbolTable* catchSymbolTable = catchEnvironment->symbolTable();
+    RELEASE_ASSERT(catchSymbolTable->size() == 1);
+    PropertyName errorName(catchSymbolTable->begin(catchSymbolTable->m_lock)->key.get());
+    PropertySlot slot(m_scope.get(), PropertySlot::InternalMethodType::Get);
+    bool success = catchEnvironment->getOwnPropertySlot(catchEnvironment, exec, errorName, slot);
+    RELEASE_ASSERT(success && slot.isValue());
+    return slot.getValue(exec, errorName);
+}
+
+} // namespace JSC
diff --git a/Source/JavaScriptCore/debugger/DebuggerScope.h b/Source/JavaScriptCore/debugger/DebuggerScope.h
new file mode 100644
index 000000000..fef60c899
--- /dev/null
+++ b/Source/JavaScriptCore/debugger/DebuggerScope.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2008-2009, 2014 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef DebuggerScope_h
+#define DebuggerScope_h
+
+#include "JSObject.h"
+
+namespace JSC {
+
+class DebuggerCallFrame;
+class JSScope;
+
+class DebuggerScope : public JSNonFinalObject {
+public:
+    typedef JSNonFinalObject Base;
+    static const unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetPropertyNames;
+
+    static DebuggerScope* create(VM& vm, JSScope* scope)
+    {
+        DebuggerScope* debuggerScope = new (NotNull, allocateCell<DebuggerScope>(vm.heap)) DebuggerScope(vm, scope);
+        debuggerScope->finishCreation(vm);
+        return debuggerScope;
+    }
+
+    static void visitChildren(JSCell*, SlotVisitor&);
+    static String className(const JSObject*);
+    static bool getOwnPropertySlot(JSObject*, ExecState*, PropertyName, PropertySlot&);
+    static void put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
+    static bool deleteProperty(JSCell*, ExecState*, PropertyName);
+    static void getOwnPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
+    static bool defineOwnProperty(JSObject*, ExecState*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
+
+    DECLARE_EXPORT_INFO;
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject) 
+    {
+        return Structure::create(vm, globalObject, jsNull(), TypeInfo(ObjectType, StructureFlags), info()); 
+    }
+
+    class iterator {
+    public:
+        iterator(DebuggerScope* node)
+            : m_node(node)
+        {
+        }
+
+        DebuggerScope* get() { return m_node; }
+        iterator& operator++() { m_node = m_node->next(); return *this; }
+        // postfix ++ intentionally omitted
+
+        bool operator==(const iterator& other) const { return m_node == other.m_node; }
+        bool operator!=(const iterator& other) const { return m_node != other.m_node; }
+
+    private:
+        DebuggerScope* m_node;
+    };
+
+    iterator begin();
+    iterator end();
+    DebuggerScope* next();
+
+    void invalidateChain();
+    bool isValid() const { return !!m_scope; }
+
+    bool isCatchScope() const;
+    bool isFunctionNameScope() const;
+    bool isWithScope() const;
+    bool isGlobalScope() const;
+    bool isClosureScope() const;
+    bool isGlobalLexicalEnvironment() const;
+    bool isNestedLexicalScope() const;
+
+    JSValue caughtValue(ExecState*) const;
+
+private:
+    JS_EXPORT_PRIVATE DebuggerScope(VM&, JSScope*);
+    JS_EXPORT_PRIVATE void finishCreation(VM&);
+
+    JSScope* jsScope() const { return m_scope.get(); }
+
+    WriteBarrier<JSScope> m_scope;
+    WriteBarrier<DebuggerScope> m_next;
+
+    friend class DebuggerCallFrame;
+};
+
+inline DebuggerScope::iterator DebuggerScope::begin()
+{
+    return iterator(this); 
+}
+
+inline DebuggerScope::iterator DebuggerScope::end()
+{ 
+    return iterator(0); 
+}
+
+} // namespace JSC
+
+#endif // DebuggerScope_h
diff --git a/Source/JavaScriptCore/debugger/ScriptProfilingScope.h b/Source/JavaScriptCore/debugger/ScriptProfilingScope.h
new file mode 100644
index 000000000..ba6bdfc51
--- /dev/null
+++ b/Source/JavaScriptCore/debugger/ScriptProfilingScope.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2015 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef ScriptProfilingScope_h
+#define ScriptProfilingScope_h
+
+#include "Debugger.h"
+#include "JSGlobalObject.h"
+#include <wtf/Optional.h>
+
+namespace JSC {
+
+class ScriptProfilingScope {
+public:
+    ScriptProfilingScope(JSGlobalObject* globalObject, ProfilingReason reason)
+        : m_globalObject(globalObject)
+        , m_reason(reason)
+    {
+        if (shouldStartProfile())
+            m_startTime = m_globalObject->debugger()->willEvaluateScript();
+    }
+
+    ~ScriptProfilingScope()
+    {
+        if (shouldEndProfile())
+            m_globalObject->debugger()->didEvaluateScript(m_startTime.value(), m_reason);
+    }
+
+private:
+    bool shouldStartProfile() const
+    {
+        if (!m_globalObject)
+            return false;
+
+        if (!m_globalObject->hasDebugger())
+            return false;
+
+        if (!m_globalObject->debugger()->hasProfilingClient())
+            return false;
+
+        if (m_globalObject->debugger()->isAlreadyProfiling())
+            return false;
+
+        return true;
+    }
+
+    bool shouldEndProfile() const
+    {
+        // Did not start a profile.
+        if (!m_startTime)
+            return false;
+
+        // Debugger may have been removed.
+        if (!m_globalObject->hasDebugger())
+            return false;
+
+        // Profiling Client may have been removed.
+        if (!m_globalObject->debugger()->hasProfilingClient())
+            return false;
+
+        return true;
+    }
+
+    JSGlobalObject* m_globalObject { nullptr };
+    Optional<double> m_startTime;
+    ProfilingReason m_reason;
+};
+
+}
+
+#endif // ScriptProfilingScope_h