From 7f65b2f4c873a32f4d8e3c3ad8d339c57173a7b5 Mon Sep 17 00:00:00 2001
From: Feng Qian <fqian@google.com>
Date: Fri, 19 Jun 2009 10:50:20 -0700
Subject: Remove v8 source form webkit

Will drop a newer revision to V8Binding/ directory.
---
 v8/src/debug.cc | 2229 -------------------------------------------------------
 1 file changed, 2229 deletions(-)
 delete mode 100644 v8/src/debug.cc

(limited to 'v8/src/debug.cc')

diff --git a/v8/src/debug.cc b/v8/src/debug.cc
deleted file mode 100644
index 99ae423..0000000
--- a/v8/src/debug.cc
+++ /dev/null
@@ -1,2229 +0,0 @@
-// Copyright 2006-2008 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * 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.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
-// OWNER 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 "v8.h"
-
-#include "api.h"
-#include "arguments.h"
-#include "bootstrapper.h"
-#include "code-stubs.h"
-#include "compiler.h"
-#include "debug.h"
-#include "execution.h"
-#include "global-handles.h"
-#include "natives.h"
-#include "stub-cache.h"
-#include "log.h"
-
-namespace v8 { namespace internal {
-
-#ifdef ENABLE_DEBUGGER_SUPPORT
-static void PrintLn(v8::Local<v8::Value> value) {
-  v8::Local<v8::String> s = value->ToString();
-  char* data = NewArray<char>(s->Length() + 1);
-  if (data == NULL) {
-    V8::FatalProcessOutOfMemory("PrintLn");
-    return;
-  }
-  s->WriteAscii(data);
-  PrintF("%s\n", data);
-  DeleteArray(data);
-}
-
-
-static Handle<Code> ComputeCallDebugBreak(int argc) {
-  CALL_HEAP_FUNCTION(StubCache::ComputeCallDebugBreak(argc), Code);
-}
-
-
-static Handle<Code> ComputeCallDebugPrepareStepIn(int argc) {
-  CALL_HEAP_FUNCTION(StubCache::ComputeCallDebugPrepareStepIn(argc), Code);
-}
-
-
-BreakLocationIterator::BreakLocationIterator(Handle<DebugInfo> debug_info,
-                                             BreakLocatorType type) {
-  debug_info_ = debug_info;
-  type_ = type;
-  reloc_iterator_ = NULL;
-  reloc_iterator_original_ = NULL;
-  Reset();  // Initialize the rest of the member variables.
-}
-
-
-BreakLocationIterator::~BreakLocationIterator() {
-  ASSERT(reloc_iterator_ != NULL);
-  ASSERT(reloc_iterator_original_ != NULL);
-  delete reloc_iterator_;
-  delete reloc_iterator_original_;
-}
-
-
-void BreakLocationIterator::Next() {
-  AssertNoAllocation nogc;
-  ASSERT(!RinfoDone());
-
-  // Iterate through reloc info for code and original code stopping at each
-  // breakable code target.
-  bool first = break_point_ == -1;
-  while (!RinfoDone()) {
-    if (!first) RinfoNext();
-    first = false;
-    if (RinfoDone()) return;
-
-    // Whenever a statement position or (plain) position is passed update the
-    // current value of these.
-    if (RelocInfo::IsPosition(rmode())) {
-      if (RelocInfo::IsStatementPosition(rmode())) {
-        statement_position_ =
-            rinfo()->data() - debug_info_->shared()->start_position();
-      }
-      // Always update the position as we don't want that to be before the
-      // statement position.
-      position_ = rinfo()->data() - debug_info_->shared()->start_position();
-      ASSERT(position_ >= 0);
-      ASSERT(statement_position_ >= 0);
-    }
-
-    // Check for breakable code target. Look in the original code as setting
-    // break points can cause the code targets in the running (debugged) code to
-    // be of a different kind than in the original code.
-    if (RelocInfo::IsCodeTarget(rmode())) {
-      Address target = original_rinfo()->target_address();
-      Code* code = Code::GetCodeFromTargetAddress(target);
-      if (code->is_inline_cache_stub() || RelocInfo::IsConstructCall(rmode())) {
-        break_point_++;
-        return;
-      }
-      if (code->kind() == Code::STUB) {
-        if (type_ == ALL_BREAK_LOCATIONS) {
-          if (Debug::IsBreakStub(code)) {
-            break_point_++;
-            return;
-          }
-        } else {
-          ASSERT(type_ == SOURCE_BREAK_LOCATIONS);
-          if (Debug::IsSourceBreakStub(code)) {
-            break_point_++;
-            return;
-          }
-        }
-      }
-    }
-
-    // Check for break at return.
-    if (RelocInfo::IsJSReturn(rmode())) {
-      // Set the positions to the end of the function.
-      if (debug_info_->shared()->HasSourceCode()) {
-        position_ = debug_info_->shared()->end_position() -
-                    debug_info_->shared()->start_position();
-      } else {
-        position_ = 0;
-      }
-      statement_position_ = position_;
-      break_point_++;
-      return;
-    }
-  }
-}
-
-
-void BreakLocationIterator::Next(int count) {
-  while (count > 0) {
-    Next();
-    count--;
-  }
-}
-
-
-// Find the break point closest to the supplied address.
-void BreakLocationIterator::FindBreakLocationFromAddress(Address pc) {
-  // Run through all break points to locate the one closest to the address.
-  int closest_break_point = 0;
-  int distance = kMaxInt;
-  while (!Done()) {
-    // Check if this break point is closer that what was previously found.
-    if (this->pc() < pc && pc - this->pc() < distance) {
-      closest_break_point = break_point();
-      distance = pc - this->pc();
-      // Check whether we can't get any closer.
-      if (distance == 0) break;
-    }
-    Next();
-  }
-
-  // Move to the break point found.
-  Reset();
-  Next(closest_break_point);
-}
-
-
-// Find the break point closest to the supplied source position.
-void BreakLocationIterator::FindBreakLocationFromPosition(int position) {
-  // Run through all break points to locate the one closest to the source
-  // position.
-  int closest_break_point = 0;
-  int distance = kMaxInt;
-  while (!Done()) {
-    // Check if this break point is closer that what was previously found.
-    if (position <= statement_position() &&
-        statement_position() - position < distance) {
-      closest_break_point = break_point();
-      distance = statement_position() - position;
-      // Check whether we can't get any closer.
-      if (distance == 0) break;
-    }
-    Next();
-  }
-
-  // Move to the break point found.
-  Reset();
-  Next(closest_break_point);
-}
-
-
-void BreakLocationIterator::Reset() {
-  // Create relocation iterators for the two code objects.
-  if (reloc_iterator_ != NULL) delete reloc_iterator_;
-  if (reloc_iterator_original_ != NULL) delete reloc_iterator_original_;
-  reloc_iterator_ = new RelocIterator(debug_info_->code());
-  reloc_iterator_original_ = new RelocIterator(debug_info_->original_code());
-
-  // Position at the first break point.
-  break_point_ = -1;
-  position_ = 1;
-  statement_position_ = 1;
-  Next();
-}
-
-
-bool BreakLocationIterator::Done() const {
-  return RinfoDone();
-}
-
-
-void BreakLocationIterator::SetBreakPoint(Handle<Object> break_point_object) {
-  // If there is not already a real break point here patch code with debug
-  // break.
-  if (!HasBreakPoint()) {
-    SetDebugBreak();
-  }
-  ASSERT(IsDebugBreak());
-  // Set the break point information.
-  DebugInfo::SetBreakPoint(debug_info_, code_position(),
-                           position(), statement_position(),
-                           break_point_object);
-}
-
-
-void BreakLocationIterator::ClearBreakPoint(Handle<Object> break_point_object) {
-  // Clear the break point information.
-  DebugInfo::ClearBreakPoint(debug_info_, code_position(), break_point_object);
-  // If there are no more break points here remove the debug break.
-  if (!HasBreakPoint()) {
-    ClearDebugBreak();
-    ASSERT(!IsDebugBreak());
-  }
-}
-
-
-void BreakLocationIterator::SetOneShot() {
-  // If there is a real break point here no more to do.
-  if (HasBreakPoint()) {
-    ASSERT(IsDebugBreak());
-    return;
-  }
-
-  // Patch code with debug break.
-  SetDebugBreak();
-}
-
-
-void BreakLocationIterator::ClearOneShot() {
-  // If there is a real break point here no more to do.
-  if (HasBreakPoint()) {
-    ASSERT(IsDebugBreak());
-    return;
-  }
-
-  // Patch code removing debug break.
-  ClearDebugBreak();
-  ASSERT(!IsDebugBreak());
-}
-
-
-void BreakLocationIterator::SetDebugBreak() {
-  // If there is already a break point here just return. This might happen if
-  // the same code is flooded with break points twice. Flooding the same
-  // function twice might happen when stepping in a function with an exception
-  // handler as the handler and the function is the same.
-  if (IsDebugBreak()) {
-    return;
-  }
-
-  if (RelocInfo::IsJSReturn(rmode())) {
-    // Patch the frame exit code with a break point.
-    SetDebugBreakAtReturn();
-  } else {
-    // Patch the original code with the current address as the current address
-    // might have changed by the inline caching since the code was copied.
-    original_rinfo()->set_target_address(rinfo()->target_address());
-
-    // Patch the code to invoke the builtin debug break function matching the
-    // calling convention used by the call site.
-    Handle<Code> dbgbrk_code(Debug::FindDebugBreak(rinfo()));
-    rinfo()->set_target_address(dbgbrk_code->entry());
-  }
-  ASSERT(IsDebugBreak());
-}
-
-
-void BreakLocationIterator::ClearDebugBreak() {
-  if (RelocInfo::IsJSReturn(rmode())) {
-    // Restore the frame exit code.
-    ClearDebugBreakAtReturn();
-  } else {
-    // Patch the code to the original invoke.
-    rinfo()->set_target_address(original_rinfo()->target_address());
-  }
-  ASSERT(!IsDebugBreak());
-}
-
-
-void BreakLocationIterator::PrepareStepIn() {
-  HandleScope scope;
-
-  // Step in can only be prepared if currently positioned on an IC call or
-  // construct call.
-  Address target = rinfo()->target_address();
-  Code* code = Code::GetCodeFromTargetAddress(target);
-  if (code->is_call_stub()) {
-    // Step in through IC call is handled by the runtime system. Therefore make
-    // sure that the any current IC is cleared and the runtime system is
-    // called. If the executing code has a debug break at the location change
-    // the call in the original code as it is the code there that will be
-    // executed in place of the debug break call.
-    Handle<Code> stub = ComputeCallDebugPrepareStepIn(code->arguments_count());
-    if (IsDebugBreak()) {
-      original_rinfo()->set_target_address(stub->entry());
-    } else {
-      rinfo()->set_target_address(stub->entry());
-    }
-  } else {
-    // Step in through constructs call requires no changes to the running code.
-    ASSERT(RelocInfo::IsConstructCall(rmode()));
-  }
-}
-
-
-// Check whether the break point is at a position which will exit the function.
-bool BreakLocationIterator::IsExit() const {
-  return (RelocInfo::IsJSReturn(rmode()));
-}
-
-
-bool BreakLocationIterator::HasBreakPoint() {
-  return debug_info_->HasBreakPoint(code_position());
-}
-
-
-// Check whether there is a debug break at the current position.
-bool BreakLocationIterator::IsDebugBreak() {
-  if (RelocInfo::IsJSReturn(rmode())) {
-    return IsDebugBreakAtReturn();
-  } else {
-    return Debug::IsDebugBreak(rinfo()->target_address());
-  }
-}
-
-
-Object* BreakLocationIterator::BreakPointObjects() {
-  return debug_info_->GetBreakPointObjects(code_position());
-}
-
-
-// Clear out all the debug break code. This is ONLY supposed to be used when
-// shutting down the debugger as it will leave the break point information in
-// DebugInfo even though the code is patched back to the non break point state.
-void BreakLocationIterator::ClearAllDebugBreak() {
-  while (!Done()) {
-    ClearDebugBreak();
-    Next();
-  }
-}
-
-
-bool BreakLocationIterator::RinfoDone() const {
-  ASSERT(reloc_iterator_->done() == reloc_iterator_original_->done());
-  return reloc_iterator_->done();
-}
-
-
-void BreakLocationIterator::RinfoNext() {
-  reloc_iterator_->next();
-  reloc_iterator_original_->next();
-#ifdef DEBUG
-  ASSERT(reloc_iterator_->done() == reloc_iterator_original_->done());
-  if (!reloc_iterator_->done()) {
-    ASSERT(rmode() == original_rmode());
-  }
-#endif
-}
-
-
-bool Debug::has_break_points_ = false;
-DebugInfoListNode* Debug::debug_info_list_ = NULL;
-
-
-// Threading support.
-void Debug::ThreadInit() {
-  thread_local_.break_count_ = 0;
-  thread_local_.break_id_ = 0;
-  thread_local_.break_frame_id_ = StackFrame::NO_ID;
-  thread_local_.last_step_action_ = StepNone;
-  thread_local_.last_statement_position_ = RelocInfo::kNoPosition;
-  thread_local_.step_count_ = 0;
-  thread_local_.last_fp_ = 0;
-  thread_local_.step_into_fp_ = 0;
-  thread_local_.after_break_target_ = 0;
-  thread_local_.debugger_entry_ = NULL;
-  thread_local_.preemption_pending_ = false;
-}
-
-
-JSCallerSavedBuffer Debug::registers_;
-Debug::ThreadLocal Debug::thread_local_;
-
-
-char* Debug::ArchiveDebug(char* storage) {
-  char* to = storage;
-  memcpy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
-  to += sizeof(ThreadLocal);
-  memcpy(to, reinterpret_cast<char*>(&registers_), sizeof(registers_));
-  ThreadInit();
-  ASSERT(to <= storage + ArchiveSpacePerThread());
-  return storage + ArchiveSpacePerThread();
-}
-
-
-char* Debug::RestoreDebug(char* storage) {
-  char* from = storage;
-  memcpy(reinterpret_cast<char*>(&thread_local_), from, sizeof(ThreadLocal));
-  from += sizeof(ThreadLocal);
-  memcpy(reinterpret_cast<char*>(&registers_), from, sizeof(registers_));
-  ASSERT(from <= storage + ArchiveSpacePerThread());
-  return storage + ArchiveSpacePerThread();
-}
-
-
-int Debug::ArchiveSpacePerThread() {
-  return sizeof(ThreadLocal) + sizeof(registers_);
-}
-
-
-// Default break enabled.
-bool Debug::disable_break_ = false;
-
-// Default call debugger on uncaught exception.
-bool Debug::break_on_exception_ = false;
-bool Debug::break_on_uncaught_exception_ = true;
-
-Handle<Context> Debug::debug_context_ = Handle<Context>();
-Code* Debug::debug_break_return_entry_ = NULL;
-Code* Debug::debug_break_return_ = NULL;
-
-
-void Debug::HandleWeakDebugInfo(v8::Persistent<v8::Value> obj, void* data) {
-  DebugInfoListNode* node = reinterpret_cast<DebugInfoListNode*>(data);
-  RemoveDebugInfo(node->debug_info());
-#ifdef DEBUG
-  node = Debug::debug_info_list_;
-  while (node != NULL) {
-    ASSERT(node != reinterpret_cast<DebugInfoListNode*>(data));
-    node = node->next();
-  }
-#endif
-}
-
-
-DebugInfoListNode::DebugInfoListNode(DebugInfo* debug_info): next_(NULL) {
-  // Globalize the request debug info object and make it weak.
-  debug_info_ = Handle<DebugInfo>::cast((GlobalHandles::Create(debug_info)));
-  GlobalHandles::MakeWeak(reinterpret_cast<Object**>(debug_info_.location()),
-                          this, Debug::HandleWeakDebugInfo);
-}
-
-
-DebugInfoListNode::~DebugInfoListNode() {
-  GlobalHandles::Destroy(reinterpret_cast<Object**>(debug_info_.location()));
-}
-
-
-void Debug::Setup(bool create_heap_objects) {
-  ThreadInit();
-  if (create_heap_objects) {
-    // Get code to handle entry to debug break on return.
-    debug_break_return_entry_ =
-        Builtins::builtin(Builtins::Return_DebugBreakEntry);
-    ASSERT(debug_break_return_entry_->IsCode());
-
-    // Get code to handle debug break on return.
-    debug_break_return_ =
-        Builtins::builtin(Builtins::Return_DebugBreak);
-    ASSERT(debug_break_return_->IsCode());
-  }
-}
-
-
-bool Debug::CompileDebuggerScript(int index) {
-  HandleScope scope;
-
-  // Bail out if the index is invalid.
-  if (index == -1) {
-    return false;
-  }
-
-  // Find source and name for the requested script.
-  Handle<String> source_code = Bootstrapper::NativesSourceLookup(index);
-  Vector<const char> name = Natives::GetScriptName(index);
-  Handle<String> script_name = Factory::NewStringFromAscii(name);
-
-  // Compile the script.
-  bool allow_natives_syntax = FLAG_allow_natives_syntax;
-  FLAG_allow_natives_syntax = true;
-  Handle<JSFunction> boilerplate;
-  boilerplate = Compiler::Compile(source_code, script_name, 0, 0, NULL, NULL);
-  FLAG_allow_natives_syntax = allow_natives_syntax;
-
-  // Silently ignore stack overflows during compilation.
-  if (boilerplate.is_null()) {
-    ASSERT(Top::has_pending_exception());
-    Top::clear_pending_exception();
-    return false;
-  }
-
-  // Execute the boilerplate function in the debugger context.
-  Handle<Context> context = Top::global_context();
-  bool caught_exception = false;
-  Handle<JSFunction> function =
-      Factory::NewFunctionFromBoilerplate(boilerplate, context);
-  Handle<Object> result =
-      Execution::TryCall(function, Handle<Object>(context->global()),
-                         0, NULL, &caught_exception);
-
-  // Check for caught exceptions.
-  if (caught_exception) {
-    Handle<Object> message = MessageHandler::MakeMessageObject(
-        "error_loading_debugger", NULL, HandleVector<Object>(&result, 1),
-        Handle<String>());
-    MessageHandler::ReportMessage(NULL, message);
-    return false;
-  }
-
-  // Mark this script as native and return successfully.
-  Handle<Script> script(Script::cast(function->shared()->script()));
-  script->set_type(Smi::FromInt(SCRIPT_TYPE_NATIVE));
-  return true;
-}
-
-
-bool Debug::Load() {
-  // Return if debugger is already loaded.
-  if (IsLoaded()) return true;
-
-  // Bail out if we're already in the process of compiling the native
-  // JavaScript source code for the debugger.
-  if (Debugger::compiling_natives() || Debugger::is_loading_debugger())
-    return false;
-  Debugger::set_loading_debugger(true);
-
-  // Disable breakpoints and interrupts while compiling and running the
-  // debugger scripts including the context creation code.
-  DisableBreak disable(true);
-  PostponeInterruptsScope postpone;
-
-  // Create the debugger context.
-  HandleScope scope;
-  Handle<Context> context =
-      Bootstrapper::CreateEnvironment(Handle<Object>::null(),
-                                      v8::Handle<ObjectTemplate>(),
-                                      NULL);
-
-  // Use the debugger context.
-  SaveContext save;
-  Top::set_context(*context);
-
-  // Expose the builtins object in the debugger context.
-  Handle<String> key = Factory::LookupAsciiSymbol("builtins");
-  Handle<GlobalObject> global = Handle<GlobalObject>(context->global());
-  SetProperty(global, key, Handle<Object>(global->builtins()), NONE);
-
-  // Compile the JavaScript for the debugger in the debugger context.
-  Debugger::set_compiling_natives(true);
-  bool caught_exception =
-      !CompileDebuggerScript(Natives::GetIndex("mirror")) ||
-      !CompileDebuggerScript(Natives::GetIndex("debug"));
-  Debugger::set_compiling_natives(false);
-
-  // Make sure we mark the debugger as not loading before we might
-  // return.
-  Debugger::set_loading_debugger(false);
-
-  // Check for caught exceptions.
-  if (caught_exception) return false;
-
-  // Debugger loaded.
-  debug_context_ = Handle<Context>::cast(GlobalHandles::Create(*context));
-  return true;
-}
-
-
-void Debug::Unload() {
-  // Return debugger is not loaded.
-  if (!IsLoaded()) {
-    return;
-  }
-
-  // Clear debugger context global handle.
-  GlobalHandles::Destroy(reinterpret_cast<Object**>(debug_context_.location()));
-  debug_context_ = Handle<Context>();
-}
-
-
-// Set the flag indicating that preemption happened during debugging.
-void Debug::PreemptionWhileInDebugger() {
-  ASSERT(InDebugger());
-  Debug::set_preemption_pending(true);
-}
-
-
-void Debug::Iterate(ObjectVisitor* v) {
-  v->VisitPointer(bit_cast<Object**, Code**>(&(debug_break_return_entry_)));
-  v->VisitPointer(bit_cast<Object**, Code**>(&(debug_break_return_)));
-}
-
-
-Object* Debug::Break(Arguments args) {
-  HandleScope scope;
-  ASSERT(args.length() == 0);
-
-  // Get the top-most JavaScript frame.
-  JavaScriptFrameIterator it;
-  JavaScriptFrame* frame = it.frame();
-
-  // Just continue if breaks are disabled or debugger cannot be loaded.
-  if (disable_break() || !Load()) {
-    SetAfterBreakTarget(frame);
-    return Heap::undefined_value();
-  }
-
-  // Enter the debugger.
-  EnterDebugger debugger;
-  if (debugger.FailedToEnter()) {
-    return Heap::undefined_value();
-  }
-
-  // Postpone interrupt during breakpoint processing.
-  PostponeInterruptsScope postpone;
-
-  // Get the debug info (create it if it does not exist).
-  Handle<SharedFunctionInfo> shared =
-      Handle<SharedFunctionInfo>(JSFunction::cast(frame->function())->shared());
-  Handle<DebugInfo> debug_info = GetDebugInfo(shared);
-
-  // Find the break point where execution has stopped.
-  BreakLocationIterator break_location_iterator(debug_info,
-                                                ALL_BREAK_LOCATIONS);
-  break_location_iterator.FindBreakLocationFromAddress(frame->pc());
-
-  // Check whether step next reached a new statement.
-  if (!StepNextContinue(&break_location_iterator, frame)) {
-    // Decrease steps left if performing multiple steps.
-    if (thread_local_.step_count_ > 0) {
-      thread_local_.step_count_--;
-    }
-  }
-
-  // If there is one or more real break points check whether any of these are
-  // triggered.
-  Handle<Object> break_points_hit(Heap::undefined_value());
-  if (break_location_iterator.HasBreakPoint()) {
-    Handle<Object> break_point_objects =
-        Handle<Object>(break_location_iterator.BreakPointObjects());
-    break_points_hit = CheckBreakPoints(break_point_objects);
-  }
-
-  // Notify debugger if a real break point is triggered or if performing single
-  // stepping with no more steps to perform. Otherwise do another step.
-  if (!break_points_hit->IsUndefined() ||
-    (thread_local_.last_step_action_ != StepNone &&
-     thread_local_.step_count_ == 0)) {
-    // Clear all current stepping setup.
-    ClearStepping();
-
-    // Notify the debug event listeners.
-    Debugger::OnDebugBreak(break_points_hit, false);
-  } else if (thread_local_.last_step_action_ != StepNone) {
-    // Hold on to last step action as it is cleared by the call to
-    // ClearStepping.
-    StepAction step_action = thread_local_.last_step_action_;
-    int step_count = thread_local_.step_count_;
-
-    // Clear all current stepping setup.
-    ClearStepping();
-
-    // Set up for the remaining steps.
-    PrepareStep(step_action, step_count);
-  }
-
-  // Install jump to the call address which was overwritten.
-  SetAfterBreakTarget(frame);
-
-  return Heap::undefined_value();
-}
-
-
-// Check the break point objects for whether one or more are actually
-// triggered. This function returns a JSArray with the break point objects
-// which is triggered.
-Handle<Object> Debug::CheckBreakPoints(Handle<Object> break_point_objects) {
-  int break_points_hit_count = 0;
-  Handle<JSArray> break_points_hit = Factory::NewJSArray(1);
-
-  // If there are multiple break points they are in a FixedArray.
-  ASSERT(!break_point_objects->IsUndefined());
-  if (break_point_objects->IsFixedArray()) {
-    Handle<FixedArray> array(FixedArray::cast(*break_point_objects));
-    for (int i = 0; i < array->length(); i++) {
-      Handle<Object> o(array->get(i));
-      if (CheckBreakPoint(o)) {
-        break_points_hit->SetElement(break_points_hit_count++, *o);
-      }
-    }
-  } else {
-    if (CheckBreakPoint(break_point_objects)) {
-      break_points_hit->SetElement(break_points_hit_count++,
-                                   *break_point_objects);
-    }
-  }
-
-  // Return undefined if no break points where triggered.
-  if (break_points_hit_count == 0) {
-    return Factory::undefined_value();
-  }
-  return break_points_hit;
-}
-
-
-// Check whether a single break point object is triggered.
-bool Debug::CheckBreakPoint(Handle<Object> break_point_object) {
-  HandleScope scope;
-
-  // Ignore check if break point object is not a JSObject.
-  if (!break_point_object->IsJSObject()) return true;
-
-  // Get the function CheckBreakPoint (defined in debug.js).
-  Handle<JSFunction> check_break_point =
-    Handle<JSFunction>(JSFunction::cast(
-      debug_context()->global()->GetProperty(
-          *Factory::LookupAsciiSymbol("IsBreakPointTriggered"))));
-
-  // Get the break id as an object.
-  Handle<Object> break_id = Factory::NewNumberFromInt(Debug::break_id());
-
-  // Call HandleBreakPointx.
-  bool caught_exception = false;
-  const int argc = 2;
-  Object** argv[argc] = {
-    break_id.location(),
-    reinterpret_cast<Object**>(break_point_object.location())
-  };
-  Handle<Object> result = Execution::TryCall(check_break_point,
-                                             Top::builtins(), argc, argv,
-                                             &caught_exception);
-
-  // If exception or non boolean result handle as not triggered
-  if (caught_exception || !result->IsBoolean()) {
-    return false;
-  }
-
-  // Return whether the break point is triggered.
-  return *result == Heap::true_value();
-}
-
-
-// Check whether the function has debug information.
-bool Debug::HasDebugInfo(Handle<SharedFunctionInfo> shared) {
-  return !shared->debug_info()->IsUndefined();
-}
-
-
-// Return the debug info for this function. EnsureDebugInfo must be called
-// prior to ensure the debug info has been generated for shared.
-Handle<DebugInfo> Debug::GetDebugInfo(Handle<SharedFunctionInfo> shared) {
-  ASSERT(HasDebugInfo(shared));
-  return Handle<DebugInfo>(DebugInfo::cast(shared->debug_info()));
-}
-
-
-void Debug::SetBreakPoint(Handle<SharedFunctionInfo> shared,
-                          int source_position,
-                          Handle<Object> break_point_object) {
-  HandleScope scope;
-
-  if (!EnsureDebugInfo(shared)) {
-    // Return if retrieving debug info failed.
-    return;
-  }
-
-  Handle<DebugInfo> debug_info = GetDebugInfo(shared);
-  // Source positions starts with zero.
-  ASSERT(source_position >= 0);
-
-  // Find the break point and change it.
-  BreakLocationIterator it(debug_info, SOURCE_BREAK_LOCATIONS);
-  it.FindBreakLocationFromPosition(source_position);
-  it.SetBreakPoint(break_point_object);
-
-  // At least one active break point now.
-  ASSERT(debug_info->GetBreakPointCount() > 0);
-}
-
-
-void Debug::ClearBreakPoint(Handle<Object> break_point_object) {
-  HandleScope scope;
-
-  DebugInfoListNode* node = debug_info_list_;
-  while (node != NULL) {
-    Object* result = DebugInfo::FindBreakPointInfo(node->debug_info(),
-                                                   break_point_object);
-    if (!result->IsUndefined()) {
-      // Get information in the break point.
-      BreakPointInfo* break_point_info = BreakPointInfo::cast(result);
-      Handle<DebugInfo> debug_info = node->debug_info();
-      Handle<SharedFunctionInfo> shared(debug_info->shared());
-      int source_position =  break_point_info->statement_position()->value();
-
-      // Source positions starts with zero.
-      ASSERT(source_position >= 0);
-
-      // Find the break point and clear it.
-      BreakLocationIterator it(debug_info, SOURCE_BREAK_LOCATIONS);
-      it.FindBreakLocationFromPosition(source_position);
-      it.ClearBreakPoint(break_point_object);
-
-      // If there are no more break points left remove the debug info for this
-      // function.
-      if (debug_info->GetBreakPointCount() == 0) {
-        RemoveDebugInfo(debug_info);
-      }
-
-      return;
-    }
-    node = node->next();
-  }
-}
-
-
-void Debug::ClearAllBreakPoints() {
-  DebugInfoListNode* node = debug_info_list_;
-  while (node != NULL) {
-    // Remove all debug break code.
-    BreakLocationIterator it(node->debug_info(), ALL_BREAK_LOCATIONS);
-    it.ClearAllDebugBreak();
-    node = node->next();
-  }
-
-  // Remove all debug info.
-  while (debug_info_list_ != NULL) {
-    RemoveDebugInfo(debug_info_list_->debug_info());
-  }
-}
-
-
-void Debug::FloodWithOneShot(Handle<SharedFunctionInfo> shared) {
-  // Make sure the function has setup the debug info.
-  if (!EnsureDebugInfo(shared)) {
-    // Return if we failed to retrieve the debug info.
-    return;
-  }
-
-  // Flood the function with break points.
-  BreakLocationIterator it(GetDebugInfo(shared), ALL_BREAK_LOCATIONS);
-  while (!it.Done()) {
-    it.SetOneShot();
-    it.Next();
-  }
-}
-
-
-void Debug::FloodHandlerWithOneShot() {
-  // Iterate through the JavaScript stack looking for handlers.
-  StackFrame::Id id = break_frame_id();
-  if (id == StackFrame::NO_ID) {
-    // If there is no JavaScript stack don't do anything.
-    return;
-  }
-  for (JavaScriptFrameIterator it(id); !it.done(); it.Advance()) {
-    JavaScriptFrame* frame = it.frame();
-    if (frame->HasHandler()) {
-      Handle<SharedFunctionInfo> shared =
-          Handle<SharedFunctionInfo>(
-              JSFunction::cast(frame->function())->shared());
-      // Flood the function with the catch block with break points
-      FloodWithOneShot(shared);
-      return;
-    }
-  }
-}
-
-
-void Debug::ChangeBreakOnException(ExceptionBreakType type, bool enable) {
-  if (type == BreakUncaughtException) {
-    break_on_uncaught_exception_ = enable;
-  } else {
-    break_on_exception_ = enable;
-  }
-}
-
-
-void Debug::PrepareStep(StepAction step_action, int step_count) {
-  HandleScope scope;
-  ASSERT(Debug::InDebugger());
-
-  // Remember this step action and count.
-  thread_local_.last_step_action_ = step_action;
-  thread_local_.step_count_ = step_count;
-
-  // Get the frame where the execution has stopped and skip the debug frame if
-  // any. The debug frame will only be present if execution was stopped due to
-  // hitting a break point. In other situations (e.g. unhandled exception) the
-  // debug frame is not present.
-  StackFrame::Id id = break_frame_id();
-  if (id == StackFrame::NO_ID) {
-    // If there is no JavaScript stack don't do anything.
-    return;
-  }
-  JavaScriptFrameIterator frames_it(id);
-  JavaScriptFrame* frame = frames_it.frame();
-
-  // First of all ensure there is one-shot break points in the top handler
-  // if any.
-  FloodHandlerWithOneShot();
-
-  // If the function on the top frame is unresolved perform step out. This will
-  // be the case when calling unknown functions and having the debugger stopped
-  // in an unhandled exception.
-  if (!frame->function()->IsJSFunction()) {
-    // Step out: Find the calling JavaScript frame and flood it with
-    // breakpoints.
-    frames_it.Advance();
-    // Fill the function to return to with one-shot break points.
-    JSFunction* function = JSFunction::cast(frames_it.frame()->function());
-    FloodWithOneShot(Handle<SharedFunctionInfo>(function->shared()));
-    return;
-  }
-
-  // Get the debug info (create it if it does not exist).
-  Handle<SharedFunctionInfo> shared =
-      Handle<SharedFunctionInfo>(JSFunction::cast(frame->function())->shared());
-  if (!EnsureDebugInfo(shared)) {
-    // Return if ensuring debug info failed.
-    return;
-  }
-  Handle<DebugInfo> debug_info = GetDebugInfo(shared);
-
-  // Find the break location where execution has stopped.
-  BreakLocationIterator it(debug_info, ALL_BREAK_LOCATIONS);
-  it.FindBreakLocationFromAddress(frame->pc());
-
-  // Compute whether or not the target is a call target.
-  bool is_call_target = false;
-  if (RelocInfo::IsCodeTarget(it.rinfo()->rmode())) {
-    Address target = it.rinfo()->target_address();
-    Code* code = Code::GetCodeFromTargetAddress(target);
-    if (code->is_call_stub()) is_call_target = true;
-  }
-
-  // If this is the last break code target step out is the only possibility.
-  if (it.IsExit() || step_action == StepOut) {
-    // Step out: If there is a JavaScript caller frame, we need to
-    // flood it with breakpoints.
-    frames_it.Advance();
-    if (!frames_it.done()) {
-      // Fill the function to return to with one-shot break points.
-      JSFunction* function = JSFunction::cast(frames_it.frame()->function());
-      FloodWithOneShot(Handle<SharedFunctionInfo>(function->shared()));
-    }
-  } else if (!(is_call_target || RelocInfo::IsConstructCall(it.rmode())) ||
-             step_action == StepNext || step_action == StepMin) {
-    // Step next or step min.
-
-    // Fill the current function with one-shot break points.
-    FloodWithOneShot(shared);
-
-    // Remember source position and frame to handle step next.
-    thread_local_.last_statement_position_ =
-        debug_info->code()->SourceStatementPosition(frame->pc());
-    thread_local_.last_fp_ = frame->fp();
-  } else {
-    // Fill the current function with one-shot break points even for step in on
-    // a call target as the function called might be a native function for
-    // which step in will not stop.
-    FloodWithOneShot(shared);
-
-    // Step in or Step in min
-    it.PrepareStepIn();
-    ActivateStepIn(frame);
-  }
-}
-
-
-// Check whether the current debug break should be reported to the debugger. It
-// is used to have step next and step in only report break back to the debugger
-// if on a different frame or in a different statement. In some situations
-// there will be several break points in the same statement when the code is
-// flooded with one-shot break points. This function helps to perform several
-// steps before reporting break back to the debugger.
-bool Debug::StepNextContinue(BreakLocationIterator* break_location_iterator,
-                             JavaScriptFrame* frame) {
-  // If the step last action was step next or step in make sure that a new
-  // statement is hit.
-  if (thread_local_.last_step_action_ == StepNext ||
-      thread_local_.last_step_action_ == StepIn) {
-    // Never continue if returning from function.
-    if (break_location_iterator->IsExit()) return false;
-
-    // Continue if we are still on the same frame and in the same statement.
-    int current_statement_position =
-        break_location_iterator->code()->SourceStatementPosition(frame->pc());
-    return thread_local_.last_fp_ == frame->fp() &&
-        thread_local_.last_statement_position_ == current_statement_position;
-  }
-
-  // No step next action - don't continue.
-  return false;
-}
-
-
-// Check whether the code object at the specified address is a debug break code
-// object.
-bool Debug::IsDebugBreak(Address addr) {
-  Code* code = Code::GetCodeFromTargetAddress(addr);
-  return code->ic_state() == DEBUG_BREAK;
-}
-
-
-// Check whether a code stub with the specified major key is a possible break
-// point location when looking for source break locations.
-bool Debug::IsSourceBreakStub(Code* code) {
-  CodeStub::Major major_key = code->major_key();
-  return major_key == CodeStub::CallFunction;
-}
-
-
-// Check whether a code stub with the specified major key is a possible break
-// location.
-bool Debug::IsBreakStub(Code* code) {
-  CodeStub::Major major_key = code->major_key();
-  return major_key == CodeStub::CallFunction ||
-         major_key == CodeStub::StackCheck;
-}
-
-
-// Find the builtin to use for invoking the debug break
-Handle<Code> Debug::FindDebugBreak(RelocInfo* rinfo) {
-  // Find the builtin debug break function matching the calling convention
-  // used by the call site.
-  RelocInfo::Mode mode = rinfo->rmode();
-
-  if (RelocInfo::IsCodeTarget(mode)) {
-    Address target = rinfo->target_address();
-    Code* code = Code::GetCodeFromTargetAddress(target);
-    if (code->is_inline_cache_stub()) {
-      if (code->is_call_stub()) {
-        return ComputeCallDebugBreak(code->arguments_count());
-      }
-      if (code->is_load_stub()) {
-        return Handle<Code>(Builtins::builtin(Builtins::LoadIC_DebugBreak));
-      }
-      if (code->is_store_stub()) {
-        return Handle<Code>(Builtins::builtin(Builtins::StoreIC_DebugBreak));
-      }
-      if (code->is_keyed_load_stub()) {
-        Handle<Code> result =
-            Handle<Code>(Builtins::builtin(Builtins::KeyedLoadIC_DebugBreak));
-        return result;
-      }
-      if (code->is_keyed_store_stub()) {
-        Handle<Code> result =
-            Handle<Code>(Builtins::builtin(Builtins::KeyedStoreIC_DebugBreak));
-        return result;
-      }
-    }
-    if (RelocInfo::IsConstructCall(mode)) {
-      Handle<Code> result =
-          Handle<Code>(Builtins::builtin(Builtins::ConstructCall_DebugBreak));
-      return result;
-    }
-    if (code->kind() == Code::STUB) {
-      ASSERT(code->major_key() == CodeStub::CallFunction ||
-             code->major_key() == CodeStub::StackCheck);
-      Handle<Code> result =
-          Handle<Code>(Builtins::builtin(Builtins::StubNoRegisters_DebugBreak));
-      return result;
-    }
-  }
-
-  UNREACHABLE();
-  return Handle<Code>::null();
-}
-
-
-// Simple function for returning the source positions for active break points.
-Handle<Object> Debug::GetSourceBreakLocations(
-    Handle<SharedFunctionInfo> shared) {
-  if (!HasDebugInfo(shared)) return Handle<Object>(Heap::undefined_value());
-  Handle<DebugInfo> debug_info = GetDebugInfo(shared);
-  if (debug_info->GetBreakPointCount() == 0) {
-    return Handle<Object>(Heap::undefined_value());
-  }
-  Handle<FixedArray> locations =
-      Factory::NewFixedArray(debug_info->GetBreakPointCount());
-  int count = 0;
-  for (int i = 0; i < debug_info->break_points()->length(); i++) {
-    if (!debug_info->break_points()->get(i)->IsUndefined()) {
-      BreakPointInfo* break_point_info =
-          BreakPointInfo::cast(debug_info->break_points()->get(i));
-      if (break_point_info->GetBreakPointCount() > 0) {
-        locations->set(count++, break_point_info->statement_position());
-      }
-    }
-  }
-  return locations;
-}
-
-
-void Debug::NewBreak(StackFrame::Id break_frame_id) {
-  thread_local_.break_frame_id_ = break_frame_id;
-  thread_local_.break_id_ = ++thread_local_.break_count_;
-}
-
-
-void Debug::SetBreak(StackFrame::Id break_frame_id, int break_id) {
-  thread_local_.break_frame_id_ = break_frame_id;
-  thread_local_.break_id_ = break_id;
-}
-
-
-// Handle stepping into a function.
-void Debug::HandleStepIn(Handle<JSFunction> function,
-                         Address fp,
-                         bool is_constructor) {
-  // If the frame pointer is not supplied by the caller find it.
-  if (fp == 0) {
-    StackFrameIterator it;
-    it.Advance();
-    // For constructor functions skip another frame.
-    if (is_constructor) {
-      ASSERT(it.frame()->is_construct());
-      it.Advance();
-    }
-    fp = it.frame()->fp();
-  }
-
-  // Flood the function with one-shot break points if it is called from where
-  // step into was requested.
-  if (fp == Debug::step_in_fp()) {
-    // Don't allow step into functions in the native context.
-    if (function->context()->global() != Top::context()->builtins()) {
-      if (function->shared()->code() ==
-          Builtins::builtin(Builtins::FunctionApply) ||
-          function->shared()->code() ==
-          Builtins::builtin(Builtins::FunctionCall)) {
-        // Handle function.apply and function.call separately to flood the
-        // function to be called and not the code for Builtins::FunctionApply or
-        // Builtins::FunctionCall. At the point of the call IC to call either
-        // Builtins::FunctionApply or Builtins::FunctionCall the expression
-        // stack has the following content:
-        //   symbol "apply" or "call"
-        //   function apply or call was called on
-        //   receiver for apply or call (first parameter to apply or call)
-        //   ... further arguments to apply or call.
-        JavaScriptFrameIterator it;
-        ASSERT(it.frame()->fp() == fp);
-        ASSERT(it.frame()->GetExpression(1)->IsJSFunction());
-        if (it.frame()->GetExpression(1)->IsJSFunction()) {
-          Handle<JSFunction>
-              actual_function(JSFunction::cast(it.frame()->GetExpression(1)));
-          Handle<SharedFunctionInfo> actual_shared(actual_function->shared());
-          Debug::FloodWithOneShot(actual_shared);
-        }
-      } else {
-        Debug::FloodWithOneShot(Handle<SharedFunctionInfo>(function->shared()));
-      }
-    }
-  }
-}
-
-
-void Debug::ClearStepping() {
-  // Clear the various stepping setup.
-  ClearOneShot();
-  ClearStepIn();
-  ClearStepNext();
-
-  // Clear multiple step counter.
-  thread_local_.step_count_ = 0;
-}
-
-// Clears all the one-shot break points that are currently set. Normally this
-// function is called each time a break point is hit as one shot break points
-// are used to support stepping.
-void Debug::ClearOneShot() {
-  // The current implementation just runs through all the breakpoints. When the
-  // last break point for a function is removed that function is automatically
-  // removed from the list.
-
-  DebugInfoListNode* node = debug_info_list_;
-  while (node != NULL) {
-    BreakLocationIterator it(node->debug_info(), ALL_BREAK_LOCATIONS);
-    while (!it.Done()) {
-      it.ClearOneShot();
-      it.Next();
-    }
-    node = node->next();
-  }
-}
-
-
-void Debug::ActivateStepIn(StackFrame* frame) {
-  thread_local_.step_into_fp_ = frame->fp();
-}
-
-
-void Debug::ClearStepIn() {
-  thread_local_.step_into_fp_ = 0;
-}
-
-
-void Debug::ClearStepNext() {
-  thread_local_.last_step_action_ = StepNone;
-  thread_local_.last_statement_position_ = RelocInfo::kNoPosition;
-  thread_local_.last_fp_ = 0;
-}
-
-
-bool Debug::EnsureCompiled(Handle<SharedFunctionInfo> shared) {
-  if (shared->is_compiled()) return true;
-  return CompileLazyShared(shared, CLEAR_EXCEPTION, 0);
-}
-
-
-// Ensures the debug information is present for shared.
-bool Debug::EnsureDebugInfo(Handle<SharedFunctionInfo> shared) {
-  // Return if we already have the debug info for shared.
-  if (HasDebugInfo(shared)) return true;
-
-  // Ensure shared in compiled. Return false if this failed.
-  if (!EnsureCompiled(shared)) return false;
-
-  // Create the debug info object.
-  Handle<DebugInfo> debug_info = Factory::NewDebugInfo(shared);
-
-  // Add debug info to the list.
-  DebugInfoListNode* node = new DebugInfoListNode(*debug_info);
-  node->set_next(debug_info_list_);
-  debug_info_list_ = node;
-
-  // Now there is at least one break point.
-  has_break_points_ = true;
-
-  return true;
-}
-
-
-void Debug::RemoveDebugInfo(Handle<DebugInfo> debug_info) {
-  ASSERT(debug_info_list_ != NULL);
-  // Run through the debug info objects to find this one and remove it.
-  DebugInfoListNode* prev = NULL;
-  DebugInfoListNode* current = debug_info_list_;
-  while (current != NULL) {
-    if (*current->debug_info() == *debug_info) {
-      // Unlink from list. If prev is NULL we are looking at the first element.
-      if (prev == NULL) {
-        debug_info_list_ = current->next();
-      } else {
-        prev->set_next(current->next());
-      }
-      current->debug_info()->shared()->set_debug_info(Heap::undefined_value());
-      delete current;
-
-      // If there are no more debug info objects there are not more break
-      // points.
-      has_break_points_ = debug_info_list_ != NULL;
-
-      return;
-    }
-    // Move to next in list.
-    prev = current;
-    current = current->next();
-  }
-  UNREACHABLE();
-}
-
-
-void Debug::SetAfterBreakTarget(JavaScriptFrame* frame) {
-  HandleScope scope;
-
-  // Get the executing function in which the debug break occurred.
-  Handle<SharedFunctionInfo> shared =
-      Handle<SharedFunctionInfo>(JSFunction::cast(frame->function())->shared());
-  if (!EnsureDebugInfo(shared)) {
-    // Return if we failed to retrieve the debug info.
-    return;
-  }
-  Handle<DebugInfo> debug_info = GetDebugInfo(shared);
-  Handle<Code> code(debug_info->code());
-  Handle<Code> original_code(debug_info->original_code());
-#ifdef DEBUG
-  // Get the code which is actually executing.
-  Handle<Code> frame_code(frame->code());
-  ASSERT(frame_code.is_identical_to(code));
-#endif
-
-  // Find the call address in the running code. This address holds the call to
-  // either a DebugBreakXXX or to the debug break return entry code if the
-  // break point is still active after processing the break point.
-  Address addr = frame->pc() - Assembler::kTargetAddrToReturnAddrDist;
-
-  // Check if the location is at JS exit.
-  bool at_js_exit = false;
-  RelocIterator it(debug_info->code());
-  while (!it.done()) {
-    if (RelocInfo::IsJSReturn(it.rinfo()->rmode())) {
-      at_js_exit = it.rinfo()->pc() == addr - 1;
-    }
-    it.next();
-  }
-
-  // Handle the jump to continue execution after break point depending on the
-  // break location.
-  if (at_js_exit) {
-    // First check if the call in the code is still the debug break return
-    // entry code. If it is the break point is still active. If not the break
-    // point was removed during break point processing.
-    if (Assembler::target_address_at(addr) ==
-        debug_break_return_entry()->entry()) {
-      // Break point still active. Jump to the corresponding place in the
-      // original code.
-      addr +=  original_code->instruction_start() - code->instruction_start();
-    }
-
-    // Move one byte back to where the call instruction was placed.
-    thread_local_.after_break_target_ = addr - 1;
-  } else {
-    // Check if there still is a debug break call at the target address. If the
-    // break point has been removed it will have disappeared. If it have
-    // disappeared don't try to look in the original code as the running code
-    // will have the right address. This takes care of the case where the last
-    // break point is removed from the function and therefore no "original code"
-    // is available. If the debug break call is still there find the address in
-    // the original code.
-    if (IsDebugBreak(Assembler::target_address_at(addr))) {
-      // If the break point is still there find the call address which was
-      // overwritten in the original code by the call to DebugBreakXXX.
-
-      // Find the corresponding address in the original code.
-      addr += original_code->instruction_start() - code->instruction_start();
-    }
-
-    // Install jump to the call address in the original code. This will be the
-    // call which was overwritten by the call to DebugBreakXXX.
-    thread_local_.after_break_target_ = Assembler::target_address_at(addr);
-  }
-}
-
-
-bool Debug::IsDebugGlobal(GlobalObject* global) {
-  return IsLoaded() && global == Debug::debug_context()->global();
-}
-
-
-void Debug::ClearMirrorCache() {
-  HandleScope scope;
-  ASSERT(Top::context() == *Debug::debug_context());
-
-  // Clear the mirror cache.
-  Handle<String> function_name =
-      Factory::LookupSymbol(CStrVector("ClearMirrorCache"));
-  Handle<Object> fun(Top::global()->GetProperty(*function_name));
-  ASSERT(fun->IsJSFunction());
-  bool caught_exception;
-  Handle<Object> js_object = Execution::TryCall(
-      Handle<JSFunction>::cast(fun),
-      Handle<JSObject>(Debug::debug_context()->global()),
-      0, NULL, &caught_exception);
-}
-
-
-Mutex* Debugger::debugger_access_ = OS::CreateMutex();
-Handle<Object> Debugger::event_listener_ = Handle<Object>();
-Handle<Object> Debugger::event_listener_data_ = Handle<Object>();
-bool Debugger::compiling_natives_ = false;
-bool Debugger::is_loading_debugger_ = false;
-bool Debugger::never_unload_debugger_ = false;
-DebugMessageThread* Debugger::message_thread_ = NULL;
-v8::DebugMessageHandler Debugger::message_handler_ = NULL;
-bool Debugger::message_handler_cleared_ = false;
-void* Debugger::message_handler_data_ = NULL;
-v8::DebugHostDispatchHandler Debugger::host_dispatch_handler_ = NULL;
-void* Debugger::host_dispatch_handler_data_ = NULL;
-DebuggerAgent* Debugger::agent_ = NULL;
-LockingMessageQueue Debugger::command_queue_(kQueueInitialSize);
-LockingMessageQueue Debugger::message_queue_(kQueueInitialSize);
-Semaphore* Debugger::command_received_ = OS::CreateSemaphore(0);
-Semaphore* Debugger::message_received_ = OS::CreateSemaphore(0);
-
-
-Handle<Object> Debugger::MakeJSObject(Vector<const char> constructor_name,
-                                      int argc, Object*** argv,
-                                      bool* caught_exception) {
-  ASSERT(Top::context() == *Debug::debug_context());
-
-  // Create the execution state object.
-  Handle<String> constructor_str = Factory::LookupSymbol(constructor_name);
-  Handle<Object> constructor(Top::global()->GetProperty(*constructor_str));
-  ASSERT(constructor->IsJSFunction());
-  if (!constructor->IsJSFunction()) {
-    *caught_exception = true;
-    return Factory::undefined_value();
-  }
-  Handle<Object> js_object = Execution::TryCall(
-      Handle<JSFunction>::cast(constructor),
-      Handle<JSObject>(Debug::debug_context()->global()), argc, argv,
-      caught_exception);
-  return js_object;
-}
-
-
-Handle<Object> Debugger::MakeExecutionState(bool* caught_exception) {
-  // Create the execution state object.
-  Handle<Object> break_id = Factory::NewNumberFromInt(Debug::break_id());
-  const int argc = 1;
-  Object** argv[argc] = { break_id.location() };
-  return MakeJSObject(CStrVector("MakeExecutionState"),
-                      argc, argv, caught_exception);
-}
-
-
-Handle<Object> Debugger::MakeBreakEvent(Handle<Object> exec_state,
-                                        Handle<Object> break_points_hit,
-                                        bool* caught_exception) {
-  // Create the new break event object.
-  const int argc = 2;
-  Object** argv[argc] = { exec_state.location(),
-                          break_points_hit.location() };
-  return MakeJSObject(CStrVector("MakeBreakEvent"),
-                      argc,
-                      argv,
-                      caught_exception);
-}
-
-
-Handle<Object> Debugger::MakeExceptionEvent(Handle<Object> exec_state,
-                                            Handle<Object> exception,
-                                            bool uncaught,
-                                            bool* caught_exception) {
-  // Create the new exception event object.
-  const int argc = 3;
-  Object** argv[argc] = { exec_state.location(),
-                          exception.location(),
-                          uncaught ? Factory::true_value().location() :
-                                     Factory::false_value().location()};
-  return MakeJSObject(CStrVector("MakeExceptionEvent"),
-                      argc, argv, caught_exception);
-}
-
-
-Handle<Object> Debugger::MakeNewFunctionEvent(Handle<Object> function,
-                                              bool* caught_exception) {
-  // Create the new function event object.
-  const int argc = 1;
-  Object** argv[argc] = { function.location() };
-  return MakeJSObject(CStrVector("MakeNewFunctionEvent"),
-                      argc, argv, caught_exception);
-}
-
-
-Handle<Object> Debugger::MakeCompileEvent(Handle<Script> script,
-                                          bool before,
-                                          bool* caught_exception) {
-  // Create the compile event object.
-  Handle<Object> exec_state = MakeExecutionState(caught_exception);
-  Handle<Object> script_wrapper = GetScriptWrapper(script);
-  const int argc = 3;
-  Object** argv[argc] = { exec_state.location(),
-                          script_wrapper.location(),
-                          before ? Factory::true_value().location() :
-                                   Factory::false_value().location() };
-
-  return MakeJSObject(CStrVector("MakeCompileEvent"),
-                      argc,
-                      argv,
-                      caught_exception);
-}
-
-
-void Debugger::OnException(Handle<Object> exception, bool uncaught) {
-  HandleScope scope;
-
-  // Bail out based on state or if there is no listener for this event
-  if (Debug::InDebugger()) return;
-  if (!Debugger::EventActive(v8::Exception)) return;
-
-  // Bail out if exception breaks are not active
-  if (uncaught) {
-    // Uncaught exceptions are reported by either flags.
-    if (!(Debug::break_on_uncaught_exception() ||
-          Debug::break_on_exception())) return;
-  } else {
-    // Caught exceptions are reported is activated.
-    if (!Debug::break_on_exception()) return;
-  }
-
-  // Enter the debugger.
-  EnterDebugger debugger;
-  if (debugger.FailedToEnter()) return;
-
-  // Clear all current stepping setup.
-  Debug::ClearStepping();
-  // Create the event data object.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
-  Handle<Object> event_data;
-  if (!caught_exception) {
-    event_data = MakeExceptionEvent(exec_state, exception, uncaught,
-                                    &caught_exception);
-  }
-  // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
-
-  // Process debug event
-  ProcessDebugEvent(v8::Exception, event_data, false);
-  // Return to continue execution from where the exception was thrown.
-}
-
-
-void Debugger::OnDebugBreak(Handle<Object> break_points_hit,
-                            bool auto_continue) {
-  HandleScope scope;
-
-  // Debugger has already been entered by caller.
-  ASSERT(Top::context() == *Debug::debug_context());
-
-  // Bail out if there is no listener for this event
-  if (!Debugger::EventActive(v8::Break)) return;
-
-  // Debugger must be entered in advance.
-  ASSERT(Top::context() == *Debug::debug_context());
-
-  // Create the event data object.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
-  Handle<Object> event_data;
-  if (!caught_exception) {
-    event_data = MakeBreakEvent(exec_state, break_points_hit,
-                                &caught_exception);
-  }
-  // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
-
-  // Process debug event
-  ProcessDebugEvent(v8::Break, event_data, auto_continue);
-}
-
-
-void Debugger::OnBeforeCompile(Handle<Script> script) {
-  HandleScope scope;
-
-  // Bail out based on state or if there is no listener for this event
-  if (Debug::InDebugger()) return;
-  if (compiling_natives()) return;
-  if (!EventActive(v8::BeforeCompile)) return;
-
-  // Enter the debugger.
-  EnterDebugger debugger;
-  if (debugger.FailedToEnter()) return;
-
-  // Create the event data object.
-  bool caught_exception = false;
-  Handle<Object> event_data = MakeCompileEvent(script, true, &caught_exception);
-  // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
-
-  // Process debug event
-  ProcessDebugEvent(v8::BeforeCompile, event_data, false);
-}
-
-
-// Handle debugger actions when a new script is compiled.
-void Debugger::OnAfterCompile(Handle<Script> script, Handle<JSFunction> fun) {
-  HandleScope scope;
-
-  // No compile events while compiling natives.
-  if (compiling_natives()) return;
-
-  // No more to do if not debugging.
-  if (!IsDebuggerActive()) return;
-
-  // Store whether in debugger before entering debugger.
-  bool in_debugger = Debug::InDebugger();
-
-  // Enter the debugger.
-  EnterDebugger debugger;
-  if (debugger.FailedToEnter()) return;
-
-  // If debugging there might be script break points registered for this
-  // script. Make sure that these break points are set.
-
-  // Get the function UpdateScriptBreakPoints (defined in debug-delay.js).
-  Handle<Object> update_script_break_points =
-      Handle<Object>(Debug::debug_context()->global()->GetProperty(
-          *Factory::LookupAsciiSymbol("UpdateScriptBreakPoints")));
-  if (!update_script_break_points->IsJSFunction()) {
-    return;
-  }
-  ASSERT(update_script_break_points->IsJSFunction());
-
-  // Wrap the script object in a proper JS object before passing it
-  // to JavaScript.
-  Handle<JSValue> wrapper = GetScriptWrapper(script);
-
-  // Call UpdateScriptBreakPoints expect no exceptions.
-  bool caught_exception = false;
-  const int argc = 1;
-  Object** argv[argc] = { reinterpret_cast<Object**>(wrapper.location()) };
-  Handle<Object> result = Execution::TryCall(
-      Handle<JSFunction>::cast(update_script_break_points),
-      Top::builtins(), argc, argv,
-      &caught_exception);
-  if (caught_exception) {
-    return;
-  }
-  // Bail out based on state or if there is no listener for this event
-  if (in_debugger) return;
-  if (!Debugger::EventActive(v8::AfterCompile)) return;
-
-  // Create the compile state object.
-  Handle<Object> event_data = MakeCompileEvent(script,
-                                               false,
-                                               &caught_exception);
-  // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
-  // Process debug event
-  ProcessDebugEvent(v8::AfterCompile, event_data, false);
-}
-
-
-void Debugger::OnNewFunction(Handle<JSFunction> function) {
-  return;
-  HandleScope scope;
-
-  // Bail out based on state or if there is no listener for this event
-  if (Debug::InDebugger()) return;
-  if (compiling_natives()) return;
-  if (!Debugger::EventActive(v8::NewFunction)) return;
-
-  // Enter the debugger.
-  EnterDebugger debugger;
-  if (debugger.FailedToEnter()) return;
-
-  // Create the event object.
-  bool caught_exception = false;
-  Handle<Object> event_data = MakeNewFunctionEvent(function, &caught_exception);
-  // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
-  // Process debug event.
-  ProcessDebugEvent(v8::NewFunction, event_data, false);
-}
-
-
-void Debugger::ProcessDebugEvent(v8::DebugEvent event,
-                                 Handle<Object> event_data,
-                                 bool auto_continue) {
-  HandleScope scope;
-
-  // Create the execution state.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
-  if (caught_exception) {
-    return;
-  }
-  // First notify the message handler if any.
-  if (message_handler_ != NULL) {
-    NotifyMessageHandler(event, exec_state, event_data, auto_continue);
-  }
-  // Notify registered debug event listener. This can be either a C or a
-  // JavaScript function.
-  if (!event_listener_.is_null()) {
-    if (event_listener_->IsProxy()) {
-      // C debug event listener.
-      Handle<Proxy> callback_obj(Handle<Proxy>::cast(event_listener_));
-      v8::DebugEventCallback callback =
-            FUNCTION_CAST<v8::DebugEventCallback>(callback_obj->proxy());
-      callback(event,
-               v8::Utils::ToLocal(Handle<JSObject>::cast(exec_state)),
-               v8::Utils::ToLocal(Handle<JSObject>::cast(event_data)),
-               v8::Utils::ToLocal(Handle<Object>::cast(event_listener_data_)));
-    } else {
-      // JavaScript debug event listener.
-      ASSERT(event_listener_->IsJSFunction());
-      Handle<JSFunction> fun(Handle<JSFunction>::cast(event_listener_));
-
-      // Invoke the JavaScript debug event listener.
-      const int argc = 4;
-      Object** argv[argc] = { Handle<Object>(Smi::FromInt(event)).location(),
-                              exec_state.location(),
-                              event_data.location(),
-                              event_listener_data_.location() };
-      Handle<Object> result = Execution::TryCall(fun, Top::global(),
-                                                 argc, argv, &caught_exception);
-      if (caught_exception) {
-        // Silently ignore exceptions from debug event listeners.
-      }
-    }
-  }
-
-  // Clear the mirror cache.
-  Debug::ClearMirrorCache();
-}
-
-
-void Debugger::UnloadDebugger() {
-  // Make sure that there are no breakpoints left.
-  Debug::ClearAllBreakPoints();
-
-  // Unload the debugger if feasible.
-  if (!never_unload_debugger_) {
-    Debug::Unload();
-  }
-
-  // Clear the flag indicating that the message handler was recently cleared.
-  message_handler_cleared_ = false;
-}
-
-
-void Debugger::NotifyMessageHandler(v8::DebugEvent event,
-                                    Handle<Object> exec_state,
-                                    Handle<Object> event_data,
-                                    bool auto_continue) {
-  HandleScope scope;
-
-  if (!Debug::Load()) return;
-
-  // Process the individual events.
-  bool interactive = false;
-  switch (event) {
-    case v8::Break:
-      interactive = true;  // Break event is always interactive
-      break;
-    case v8::Exception:
-      interactive = true;  // Exception event is always interactive
-      break;
-    case v8::BeforeCompile:
-      break;
-    case v8::AfterCompile:
-      break;
-    case v8::NewFunction:
-      break;
-    default:
-      UNREACHABLE();
-  }
-
-  // Done if not interactive.
-  if (!interactive) return;
-
-  // Get the DebugCommandProcessor.
-  v8::Local<v8::Object> api_exec_state =
-      v8::Utils::ToLocal(Handle<JSObject>::cast(exec_state));
-  v8::Local<v8::String> fun_name =
-      v8::String::New("debugCommandProcessor");
-  v8::Local<v8::Function> fun =
-      v8::Function::Cast(*api_exec_state->Get(fun_name));
-  v8::TryCatch try_catch;
-  v8::Local<v8::Object> cmd_processor =
-      v8::Object::Cast(*fun->Call(api_exec_state, 0, NULL));
-  if (try_catch.HasCaught()) {
-    PrintLn(try_catch.Exception());
-    return;
-  }
-
-  // Notify the debugger that a debug event has occurred unless auto continue is
-  // active in which case no event is send.
-  if (!auto_continue) {
-    bool success = SendEventMessage(event_data);
-    if (!success) {
-      // If failed to notify debugger just continue running.
-      return;
-    }
-  }
-
-  // Process requests from the debugger.
-  while (true) {
-    // Wait for new command in the queue.
-    command_received_->Wait();
-
-    // The debug command interrupt flag might have been set when the command was
-    // added.
-    StackGuard::Continue(DEBUGCOMMAND);
-
-    // Get the command from the queue.
-    Vector<uint16_t> command = command_queue_.Get();
-    Logger::DebugTag("Got request from command queue, in interactive loop.");
-    if (!Debugger::IsDebuggerActive()) {
-      return;
-    }
-
-    // Check if the command is a host dispatch.
-    if (command[0] == 0) {
-      if (Debugger::host_dispatch_handler_) {
-        int32_t dispatch = (command[1] << 16) | command[2];
-        Debugger::host_dispatch_handler_(reinterpret_cast<void*>(dispatch),
-                                         Debugger::host_dispatch_handler_data_);
-      }
-      if (auto_continue && !HasCommands()) {
-        return;
-      }
-      continue;
-    }
-
-    // Invoke JavaScript to process the debug request.
-    v8::Local<v8::String> fun_name;
-    v8::Local<v8::Function> fun;
-    v8::Local<v8::Value> request;
-    v8::TryCatch try_catch;
-    fun_name = v8::String::New("processDebugRequest");
-    fun = v8::Function::Cast(*cmd_processor->Get(fun_name));
-    request = v8::String::New(reinterpret_cast<uint16_t*>(command.start()),
-                              command.length());
-    static const int kArgc = 1;
-    v8::Handle<Value> argv[kArgc] = { request };
-    v8::Local<v8::Value> response_val = fun->Call(cmd_processor, kArgc, argv);
-
-    // Get the response.
-    v8::Local<v8::String> response;
-    bool running = false;
-    if (!try_catch.HasCaught()) {
-      // Get response string.
-      if (!response_val->IsUndefined()) {
-        response = v8::String::Cast(*response_val);
-      } else {
-        response = v8::String::New("");
-      }
-
-      // Log the JSON request/response.
-      if (FLAG_trace_debug_json) {
-        PrintLn(request);
-        PrintLn(response);
-      }
-
-      // Get the running state.
-      fun_name = v8::String::New("isRunning");
-      fun = v8::Function::Cast(*cmd_processor->Get(fun_name));
-      static const int kArgc = 1;
-      v8::Handle<Value> argv[kArgc] = { response };
-      v8::Local<v8::Value> running_val = fun->Call(cmd_processor, kArgc, argv);
-      if (!try_catch.HasCaught()) {
-        running = running_val->ToBoolean()->Value();
-      }
-    } else {
-      // In case of failure the result text is the exception text.
-      response = try_catch.Exception()->ToString();
-    }
-
-    // Convert text result to C string.
-    v8::String::Value val(response);
-    Vector<uint16_t> str(reinterpret_cast<uint16_t*>(*val),
-                        response->Length());
-
-    // Return the result.
-    SendMessage(str);
-
-    // Return from debug event processing if either the VM is put into the
-    // runnning state (through a continue command) or auto continue is active
-    // and there are no more commands queued.
-    if (running || (auto_continue && !HasCommands())) {
-      return;
-    }
-  }
-}
-
-
-void Debugger::SetEventListener(Handle<Object> callback,
-                                Handle<Object> data) {
-  HandleScope scope;
-
-  // Clear the global handles for the event listener and the event listener data
-  // object.
-  if (!event_listener_.is_null()) {
-    GlobalHandles::Destroy(
-        reinterpret_cast<Object**>(event_listener_.location()));
-    event_listener_ = Handle<Object>();
-  }
-  if (!event_listener_data_.is_null()) {
-    GlobalHandles::Destroy(
-        reinterpret_cast<Object**>(event_listener_data_.location()));
-    event_listener_data_ = Handle<Object>();
-  }
-
-  // If there is a new debug event listener register it together with its data
-  // object.
-  if (!callback->IsUndefined() && !callback->IsNull()) {
-    event_listener_ = Handle<Object>::cast(GlobalHandles::Create(*callback));
-    if (data.is_null()) {
-      data = Factory::undefined_value();
-    }
-    event_listener_data_ = Handle<Object>::cast(GlobalHandles::Create(*data));
-  }
-
-  // Unload the debugger if event listener cleared.
-  if (callback->IsUndefined()) {
-    UnloadDebugger();
-  }
-}
-
-
-void Debugger::SetMessageHandler(v8::DebugMessageHandler handler, void* data,
-                                 bool message_handler_thread) {
-  ScopedLock with(debugger_access_);
-
-  message_handler_ = handler;
-  message_handler_data_ = data;
-  if (handler != NULL) {
-    if (!message_thread_ && message_handler_thread) {
-      message_thread_ = new DebugMessageThread();
-      message_thread_->Start();
-    }
-  } else {
-    // Indicate that the message handler was recently cleared.
-    message_handler_cleared_ = true;
-
-    // Send an empty command to the debugger if in a break to make JavaScript
-    // run again if the debugger is closed.
-    if (Debug::InDebugger()) {
-      ProcessCommand(Vector<const uint16_t>::empty());
-    }
-  }
-}
-
-
-void Debugger::SetHostDispatchHandler(v8::DebugHostDispatchHandler handler,
-                                      void* data) {
-  host_dispatch_handler_ = handler;
-  host_dispatch_handler_data_ = data;
-}
-
-
-// Calls the registered debug message handler. This callback is part of the
-// public API. Messages are kept internally as Vector<uint16_t> strings, which
-// are allocated in various places and deallocated by the calling function
-// sometime after this call.
-void Debugger::InvokeMessageHandler(Vector<uint16_t> message) {
-  ScopedLock with(debugger_access_);
-
-  if (message_handler_ != NULL) {
-    message_handler_(message.start(), message.length(), message_handler_data_);
-  }
-}
-
-
-void Debugger::SendMessage(Vector<uint16_t> message) {
-  if (message_thread_ == NULL) {
-    // If there is no message thread just invoke the message handler from the
-    // V8 thread.
-    InvokeMessageHandler(message);
-  } else {
-    // Put a copy of the message coming from V8 on the queue. The new copy of
-    // the event string is destroyed by the message thread.
-    Vector<uint16_t> message_copy = message.Clone();
-    Logger::DebugTag("Put message on event message_queue.");
-    message_queue_.Put(message_copy);
-    message_received_->Signal();
-  }
-}
-
-
-bool Debugger::SendEventMessage(Handle<Object> event_data) {
-  v8::HandleScope scope;
-  // Call toJSONProtocol on the debug event object.
-  v8::Local<v8::Object> api_event_data =
-      v8::Utils::ToLocal(Handle<JSObject>::cast(event_data));
-  v8::Local<v8::String> fun_name = v8::String::New("toJSONProtocol");
-  v8::Local<v8::Function> fun =
-      v8::Function::Cast(*api_event_data->Get(fun_name));
-  v8::TryCatch try_catch;
-  v8::Local<v8::Value> json_event = *fun->Call(api_event_data, 0, NULL);
-  v8::Local<v8::String> json_event_string;
-  if (!try_catch.HasCaught()) {
-    if (!json_event->IsUndefined()) {
-      json_event_string = json_event->ToString();
-      if (FLAG_trace_debug_json) {
-        PrintLn(json_event_string);
-      }
-      v8::String::Value val(json_event_string);
-      Vector<uint16_t> str(reinterpret_cast<uint16_t*>(*val),
-                           json_event_string->Length());
-      SendMessage(str);
-    } else {
-      SendMessage(Vector<uint16_t>::empty());
-    }
-  } else {
-    PrintLn(try_catch.Exception());
-    return false;
-  }
-  return true;
-}
-
-
-// Puts a command coming from the public API on the queue.  Creates
-// a copy of the command string managed by the debugger.  Up to this
-// point, the command data was managed by the API client.  Called
-// by the API client thread.  This is where the API client hands off
-// processing of the command to the DebugMessageThread thread.
-// The new copy of the command is destroyed in HandleCommand().
-void Debugger::ProcessCommand(Vector<const uint16_t> command) {
-  // Make a copy of the command. Need to cast away const for Clone to work.
-  Vector<uint16_t> command_copy =
-      Vector<uint16_t>(const_cast<uint16_t*>(command.start()),
-                       command.length()).Clone();
-  Logger::DebugTag("Put command on command_queue.");
-  command_queue_.Put(command_copy);
-  command_received_->Signal();
-
-  // Set the debug command break flag to have the command processed.
-  if (!Debug::InDebugger()) {
-    StackGuard::DebugCommand();
-  }
-}
-
-
-bool Debugger::HasCommands() {
-  return !command_queue_.IsEmpty();
-}
-
-
-void Debugger::ProcessHostDispatch(void* dispatch) {
-  // Puts a host dispatch comming from the public API on the queue.
-  uint16_t hack[3];
-  hack[0] = 0;
-  hack[1] = reinterpret_cast<uint32_t>(dispatch) >> 16;
-  hack[2] = reinterpret_cast<uint32_t>(dispatch) & 0xFFFF;
-  Logger::DebugTag("Put dispatch on command_queue.");
-  command_queue_.Put(Vector<uint16_t>(hack, 3).Clone());
-  command_received_->Signal();
-
-  // Set the debug command break flag to have the host dispatch processed.
-  if (!Debug::InDebugger()) {
-    StackGuard::DebugCommand();
-  }
-}
-
-
-bool Debugger::IsDebuggerActive() {
-  ScopedLock with(debugger_access_);
-
-  return message_handler_ != NULL || !event_listener_.is_null();
-}
-
-
-Handle<Object> Debugger::Call(Handle<JSFunction> fun,
-                              Handle<Object> data,
-                              bool* pending_exception) {
-  // When calling functions in the debugger prevent it from beeing unloaded.
-  Debugger::never_unload_debugger_ = true;
-
-  // Enter the debugger.
-  EnterDebugger debugger;
-  if (debugger.FailedToEnter() || !debugger.HasJavaScriptFrames()) {
-    return Factory::undefined_value();
-  }
-
-  // Create the execution state.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
-  if (caught_exception) {
-    return Factory::undefined_value();
-  }
-
-  static const int kArgc = 2;
-  Object** argv[kArgc] = { exec_state.location(), data.location() };
-  Handle<Object> result = Execution::Call(fun, Factory::undefined_value(),
-                                          kArgc, argv, pending_exception);
-  return result;
-}
-
-
-bool Debugger::StartAgent(const char* name, int port) {
-  if (Socket::Setup()) {
-    agent_ = new DebuggerAgent(name, port);
-    agent_->Start();
-    return true;
-  }
-
-  return false;
-}
-
-
-void Debugger::StopAgent() {
-  if (agent_ != NULL) {
-    agent_->Shutdown();
-    agent_->Join();
-    delete agent_;
-    agent_ = NULL;
-  }
-}
-
-
-void Debugger::TearDown() {
-  if (message_thread_ != NULL) {
-    message_thread_->Stop();
-    delete message_thread_;
-    message_thread_ = NULL;
-  }
-}
-
-
-void DebugMessageThread::Run() {
-  // Sends debug events to an installed debugger message callback.
-  while (keep_running_) {
-    // Wait and Get are paired so that semaphore count equals queue length.
-    Debugger::message_received_->Wait();
-    Logger::DebugTag("Get message from event message_queue.");
-    Vector<uint16_t> message = Debugger::message_queue_.Get();
-    if (message.length() > 0) {
-      Debugger::InvokeMessageHandler(message);
-    }
-  }
-}
-
-
-void DebugMessageThread::Stop() {
-  keep_running_ = false;
-  Debugger::SendMessage(Vector<uint16_t>(NULL, 0));
-  Join();
-}
-
-
-MessageQueue::MessageQueue(int size) : start_(0), end_(0), size_(size) {
-  messages_ = NewArray<Vector<uint16_t> >(size);
-}
-
-
-MessageQueue::~MessageQueue() {
-  DeleteArray(messages_);
-}
-
-
-Vector<uint16_t> MessageQueue::Get() {
-  ASSERT(!IsEmpty());
-  int result = start_;
-  start_ = (start_ + 1) % size_;
-  return messages_[result];
-}
-
-
-void MessageQueue::Put(const Vector<uint16_t>& message) {
-  if ((end_ + 1) % size_ == start_) {
-    Expand();
-  }
-  messages_[end_] = message;
-  end_ = (end_ + 1) % size_;
-}
-
-
-void MessageQueue::Expand() {
-  MessageQueue new_queue(size_ * 2);
-  while (!IsEmpty()) {
-    new_queue.Put(Get());
-  }
-  Vector<uint16_t>* array_to_free = messages_;
-  *this = new_queue;
-  new_queue.messages_ = array_to_free;
-  // Automatic destructor called on new_queue, freeing array_to_free.
-}
-
-
-LockingMessageQueue::LockingMessageQueue(int size) : queue_(size) {
-  lock_ = OS::CreateMutex();
-}
-
-
-LockingMessageQueue::~LockingMessageQueue() {
-  delete lock_;
-}
-
-
-bool LockingMessageQueue::IsEmpty() const {
-  ScopedLock sl(lock_);
-  return queue_.IsEmpty();
-}
-
-
-Vector<uint16_t> LockingMessageQueue::Get() {
-  ScopedLock sl(lock_);
-  Vector<uint16_t> result = queue_.Get();
-  Logger::DebugEvent("Get", result);
-  return result;
-}
-
-
-void LockingMessageQueue::Put(const Vector<uint16_t>& message) {
-  ScopedLock sl(lock_);
-  queue_.Put(message);
-  Logger::DebugEvent("Put", message);
-}
-
-
-void LockingMessageQueue::Clear() {
-  ScopedLock sl(lock_);
-  queue_.Clear();
-}
-
-#endif  // ENABLE_DEBUGGER_SUPPORT
-
-} }  // namespace v8::internal
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