CSE2410 Fall 2014 Bounce

// Copyright 2012 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

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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_DEBUG_H_

#define V8_DEBUG_H_

#include "allocation.h"

#include "arguments.h"

#include "assembler.h"

#include "debug-agent.h"

#include "execution.h"

#include "factory.h"

#include "flags.h"

#include "frames-inl.h"

#include "hashmap.h"

#include "platform.h"

#include "platform/socket.h"

#include "string-stream.h"

#include "v8threads.h"

#ifdef ENABLE_DEBUGGER_SUPPORT

#include "../include/v8-debug.h"

namespace v8 {

namespace internal {

// Forward declarations.

class EnterDebugger;

// Step actions. NOTE: These values are in macros.py as well.

enum StepAction {

  StepNone = -1,  // Stepping not prepared.

  StepOut = 0,   // Step out of the current function.

  StepNext = 1,  // Step to the next statement in the current function.

  StepIn = 2,    // Step into new functions invoked or the next statement

                 // in the current function.

  StepMin = 3,   // Perform a minimum step in the current function.

  StepInMin = 4  // Step into new functions invoked or perform a minimum step

                 // in the current function.

};

// Type of exception break. NOTE: These values are in macros.py as well.

enum ExceptionBreakType {

  BreakException = 0,

  BreakUncaughtException = 1

};

// Type of exception break. NOTE: These values are in macros.py as well.

enum BreakLocatorType {

  ALL_BREAK_LOCATIONS = 0,

  SOURCE_BREAK_LOCATIONS = 1

};

// The different types of breakpoint position alignments.

// Must match Debug.BreakPositionAlignment in debug-debugger.js

enum BreakPositionAlignment {

  STATEMENT_ALIGNED = 0,

  BREAK_POSITION_ALIGNED = 1

};

// Class for iterating through the break points in a function and changing

// them.

class BreakLocationIterator {

 public:

  explicit BreakLocationIterator(Handle<DebugInfo> debug_info,

                                 BreakLocatorType type);

  virtual ~BreakLocationIterator();

  void Next();

  void Next(int count);

  void FindBreakLocationFromAddress(Address pc);

  void FindBreakLocationFromPosition(int position,

      BreakPositionAlignment alignment);

  void Reset();

  bool Done() const;

  void SetBreakPoint(Handle<Object> break_point_object);

  void ClearBreakPoint(Handle<Object> break_point_object);

  void SetOneShot();

  void ClearOneShot();

  bool IsStepInLocation(Isolate* isolate);

  void PrepareStepIn(Isolate* isolate);

  bool IsExit() const;

  bool HasBreakPoint();

  bool IsDebugBreak();

  Object* BreakPointObjects();

  void ClearAllDebugBreak();

  inline int code_position() {

    return static_cast<int>(pc() - debug_info_->code()->entry());

  }

  inline int break_point() { return break_point_; }

  inline int position() { return position_; }

  inline int statement_position() { return statement_position_; }

  inline Address pc() { return reloc_iterator_->rinfo()->pc(); }

  inline Code* code() { return debug_info_->code(); }

  inline RelocInfo* rinfo() { return reloc_iterator_->rinfo(); }

  inline RelocInfo::Mode rmode() const {

    return reloc_iterator_->rinfo()->rmode();

  }

  inline RelocInfo* original_rinfo() {

    return reloc_iterator_original_->rinfo();

  }

  inline RelocInfo::Mode original_rmode() const {

    return reloc_iterator_original_->rinfo()->rmode();

  }

  bool IsDebuggerStatement();

 protected:

  bool RinfoDone() const;

  void RinfoNext();

  BreakLocatorType type_;

  int break_point_;

  int position_;

  int statement_position_;

  Handle<DebugInfo> debug_info_;

  RelocIterator* reloc_iterator_;

  RelocIterator* reloc_iterator_original_;

 private:

  void SetDebugBreak();

  void ClearDebugBreak();

  void SetDebugBreakAtIC();

  void ClearDebugBreakAtIC();

  bool IsDebugBreakAtReturn();

  void SetDebugBreakAtReturn();

  void ClearDebugBreakAtReturn();

  bool IsDebugBreakSlot();

  bool IsDebugBreakAtSlot();

  void SetDebugBreakAtSlot();

  void ClearDebugBreakAtSlot();

  DISALLOW_COPY_AND_ASSIGN(BreakLocationIterator);

};

// Cache of all script objects in the heap. When a script is added a weak handle

// to it is created and that weak handle is stored in the cache. The weak handle

// callback takes care of removing the script from the cache. The key used in

// the cache is the script id.

class ScriptCache : private HashMap {

 public:

  explicit ScriptCache(Isolate* isolate)

    : HashMap(ScriptMatch), isolate_(isolate), collected_scripts_(10) {}

  virtual ~ScriptCache() { Clear(); }

  // Add script to the cache.

  void Add(Handle<Script> script);

  // Return the scripts in the cache.

  Handle<FixedArray> GetScripts();

  // Generate debugger events for collected scripts.

  void ProcessCollectedScripts();

 private:

  // Calculate the hash value from the key (script id).

  static uint32_t Hash(int key) {

    return ComputeIntegerHash(key, v8::internal::kZeroHashSeed);

  }

  // Scripts match if their keys (script id) match.

  static bool ScriptMatch(void* key1, void* key2) { return key1 == key2; }

  // Clear the cache releasing all the weak handles.

  void Clear();

  // Weak handle callback for scripts in the cache.

  static void HandleWeakScript(v8::Isolate* isolate,

                               v8::Persistent<v8::Value>* obj,

                               void* data);

  Isolate* isolate_;

  // List used during GC to temporarily store id's of collected scripts.

  List<int> collected_scripts_;

};

// Linked list holding debug info objects. The debug info objects are kept as

// weak handles to avoid a debug info object to keep a function alive.

class DebugInfoListNode {

 public:

  explicit DebugInfoListNode(DebugInfo* debug_info);

  virtual ~DebugInfoListNode();

  DebugInfoListNode* next() { return next_; }

  void set_next(DebugInfoListNode* next) { next_ = next; }

  Handle<DebugInfo> debug_info() { return debug_info_; }

 private:

  // Global (weak) handle to the debug info object.

  Handle<DebugInfo> debug_info_;

  // Next pointer for linked list.

  DebugInfoListNode* next_;

};

// This class contains the debugger support. The main purpose is to handle

// setting break points in the code.

//

// This class controls the debug info for all functions which currently have

// active breakpoints in them. This debug info is held in the heap root object

// debug_info which is a FixedArray. Each entry in this list is of class

// DebugInfo.

class Debug {

 public:

  void SetUp(bool create_heap_objects);

  bool Load();

  void Unload();

  bool IsLoaded() { return !debug_context_.is_null(); }

  bool InDebugger() { return thread_local_.debugger_entry_ != NULL; }

  void PreemptionWhileInDebugger();

  void Iterate(ObjectVisitor* v);

  Object* Break(Arguments args);

  void SetBreakPoint(Handle<JSFunction> function,

                     Handle<Object> break_point_object,

                     int* source_position);

  bool SetBreakPointForScript(Handle<Script> script,

                              Handle<Object> break_point_object,

                              int* source_position,

                              BreakPositionAlignment alignment);

  void ClearBreakPoint(Handle<Object> break_point_object);

  void ClearAllBreakPoints();

  void FloodWithOneShot(Handle<JSFunction> function);

  void FloodBoundFunctionWithOneShot(Handle<JSFunction> function);

  void FloodHandlerWithOneShot();

  void ChangeBreakOnException(ExceptionBreakType type, bool enable);

  bool IsBreakOnException(ExceptionBreakType type);

  void PrepareStep(StepAction step_action,

                   int step_count,

                   StackFrame::Id frame_id);

  void ClearStepping();

  void ClearStepOut();

  bool IsStepping() { return thread_local_.step_count_ > 0; }

  bool StepNextContinue(BreakLocationIterator* break_location_iterator,

                        JavaScriptFrame* frame);

  static Handle<DebugInfo> GetDebugInfo(Handle<SharedFunctionInfo> shared);

  static bool HasDebugInfo(Handle<SharedFunctionInfo> shared);

  void PrepareForBreakPoints();

  // This function is used in FunctionNameUsing* tests.

  Object* FindSharedFunctionInfoInScript(Handle<Script> script, int position);

  // Returns whether the operation succeeded. Compilation can only be triggered

  // if a valid closure is passed as the second argument, otherwise the shared

  // function needs to be compiled already.

  bool EnsureDebugInfo(Handle<SharedFunctionInfo> shared,

                       Handle<JSFunction> function);

  // Returns true if the current stub call is patched to call the debugger.

  static bool IsDebugBreak(Address addr);

  // Returns true if the current return statement has been patched to be

  // a debugger breakpoint.

  static bool IsDebugBreakAtReturn(RelocInfo* rinfo);

  // Check whether a code stub with the specified major key is a possible break

  // point location.

  static bool IsSourceBreakStub(Code* code);

  static bool IsBreakStub(Code* code);

  // Find the builtin to use for invoking the debug break

  static Handle<Code> FindDebugBreak(Handle<Code> code, RelocInfo::Mode mode);

  static Handle<Object> GetSourceBreakLocations(

      Handle<SharedFunctionInfo> shared,

      BreakPositionAlignment position_aligment);

  // Getter for the debug_context.

  inline Handle<Context> debug_context() { return debug_context_; }

  // Check whether a global object is the debug global object.

  bool IsDebugGlobal(GlobalObject* global);

  // Check whether this frame is just about to return.

  bool IsBreakAtReturn(JavaScriptFrame* frame);

  // Fast check to see if any break points are active.

  inline bool has_break_points() { return has_break_points_; }

  void NewBreak(StackFrame::Id break_frame_id);

  void SetBreak(StackFrame::Id break_frame_id, int break_id);

  StackFrame::Id break_frame_id() {

    return thread_local_.break_frame_id_;

  }

  int break_id() { return thread_local_.break_id_; }

  bool StepInActive() { return thread_local_.step_into_fp_ != 0; }

  void HandleStepIn(Handle<JSFunction> function,

                    Handle<Object> holder,

                    Address fp,

                    bool is_constructor);

  Address step_in_fp() { return thread_local_.step_into_fp_; }

  Address* step_in_fp_addr() { return &thread_local_.step_into_fp_; }

  bool StepOutActive() { return thread_local_.step_out_fp_ != 0; }

  Address step_out_fp() { return thread_local_.step_out_fp_; }

  EnterDebugger* debugger_entry() {

    return thread_local_.debugger_entry_;

  }

  void set_debugger_entry(EnterDebugger* entry) {

    thread_local_.debugger_entry_ = entry;

  }

  // Check whether any of the specified interrupts are pending.

  bool is_interrupt_pending(InterruptFlag what) {

    return (thread_local_.pending_interrupts_ & what) != 0;

  }

  // Set specified interrupts as pending.

  void set_interrupts_pending(InterruptFlag what) {

    thread_local_.pending_interrupts_ |= what;

  }

  // Clear specified interrupts from pending.

  void clear_interrupt_pending(InterruptFlag what) {

    thread_local_.pending_interrupts_ &= ~static_cast<int>(what);

  }

  // Getter and setter for the disable break state.

  bool disable_break() { return disable_break_; }

  void set_disable_break(bool disable_break) {

    disable_break_ = disable_break;

  }

  // Getters for the current exception break state.

  bool break_on_exception() { return break_on_exception_; }

  bool break_on_uncaught_exception() {

    return break_on_uncaught_exception_;

  }

  enum AddressId {

    k_after_break_target_address,

    k_debug_break_return_address,

    k_debug_break_slot_address,

    k_restarter_frame_function_pointer

  };

  // Support for setting the address to jump to when returning from break point.

  Address* after_break_target_address() {

    return reinterpret_cast<Address*>(&thread_local_.after_break_target_);

  }

  Address* restarter_frame_function_pointer_address() {

    Object*** address = &thread_local_.restarter_frame_function_pointer_;

    return reinterpret_cast<Address*>(address);

  }

  // Support for saving/restoring registers when handling debug break calls.

  Object** register_address(int r) {

    return &registers_[r];

  }

  // Access to the debug break on return code.

  Code* debug_break_return() { return debug_break_return_; }

  Code** debug_break_return_address() {

    return &debug_break_return_;

  }

  // Access to the debug break in debug break slot code.

  Code* debug_break_slot() { return debug_break_slot_; }

  Code** debug_break_slot_address() {

    return &debug_break_slot_;

  }

  static const int kEstimatedNofDebugInfoEntries = 16;

  static const int kEstimatedNofBreakPointsInFunction = 16;

  // Passed to MakeWeak.

  static void HandleWeakDebugInfo(v8::Isolate* isolate,

                                  v8::Persistent<v8::Value>* obj,

                                  void* data);

  friend class Debugger;

  friend Handle<FixedArray> GetDebuggedFunctions();  // In test-debug.cc

  friend void CheckDebuggerUnloaded(bool check_functions);  // In test-debug.cc

  // Threading support.

  char* ArchiveDebug(char* to);

  char* RestoreDebug(char* from);

  static int ArchiveSpacePerThread();

  void FreeThreadResources() { }

  // Mirror cache handling.

  void ClearMirrorCache();

  // Script cache handling.

  void CreateScriptCache();

  void DestroyScriptCache();

  void AddScriptToScriptCache(Handle<Script> script);

  Handle<FixedArray> GetLoadedScripts();

  // Garbage collection notifications.

  void AfterGarbageCollection();

  // Code generator routines.

  static void GenerateSlot(MacroAssembler* masm);

  static void GenerateLoadICDebugBreak(MacroAssembler* masm);

  static void GenerateStoreICDebugBreak(MacroAssembler* masm);

  static void GenerateKeyedLoadICDebugBreak(MacroAssembler* masm);

  static void GenerateKeyedStoreICDebugBreak(MacroAssembler* masm);

  static void GenerateCompareNilICDebugBreak(MacroAssembler* masm);

  static void GenerateReturnDebugBreak(MacroAssembler* masm);

  static void GenerateCallFunctionStubDebugBreak(MacroAssembler* masm);

  static void GenerateCallFunctionStubRecordDebugBreak(MacroAssembler* masm);

  static void GenerateCallConstructStubDebugBreak(MacroAssembler* masm);

  static void GenerateCallConstructStubRecordDebugBreak(MacroAssembler* masm);

  static void GenerateSlotDebugBreak(MacroAssembler* masm);

  static void GeneratePlainReturnLiveEdit(MacroAssembler* masm);

  // FrameDropper is a code replacement for a JavaScript frame with possibly

  // several frames above.

  // There is no calling conventions here, because it never actually gets

  // called, it only gets returned to.

  static void GenerateFrameDropperLiveEdit(MacroAssembler* masm);

  // Called from stub-cache.cc.

  static void GenerateCallICDebugBreak(MacroAssembler* masm);

  // Describes how exactly a frame has been dropped from stack.

  enum FrameDropMode {

    // No frame has been dropped.

    FRAMES_UNTOUCHED,

    // The top JS frame had been calling IC stub. IC stub mustn't be called now.

    FRAME_DROPPED_IN_IC_CALL,

    // The top JS frame had been calling debug break slot stub. Patch the

    // address this stub jumps to in the end.

    FRAME_DROPPED_IN_DEBUG_SLOT_CALL,

    // The top JS frame had been calling some C++ function. The return address

    // gets patched automatically.

    FRAME_DROPPED_IN_DIRECT_CALL,

    FRAME_DROPPED_IN_RETURN_CALL,

    CURRENTLY_SET_MODE

  };

  void FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,

                                    FrameDropMode mode,

                                    Object** restarter_frame_function_pointer);

  // Initializes an artificial stack frame. The data it contains is used for:

  //  a. successful work of frame dropper code which eventually gets control,

  //  b. being compatible with regular stack structure for various stack

  //     iterators.

  // Returns address of stack allocated pointer to restarted function,

  // the value that is called 'restarter_frame_function_pointer'. The value

  // at this address (possibly updated by GC) may be used later when preparing

  // 'step in' operation.

  static Object** SetUpFrameDropperFrame(StackFrame* bottom_js_frame,

                                         Handle<Code> code);

  static const int kFrameDropperFrameSize;

  // Architecture-specific constant.

  static const bool kFrameDropperSupported;

  /**

   * Defines layout of a stack frame that supports padding. This is a regular

   * internal frame that has a flexible stack structure. LiveEdit can shift

   * its lower part up the stack, taking up the 'padding' space when additional

   * stack memory is required.

   * Such frame is expected immediately above the topmost JavaScript frame.

   *

   * Stack Layout:

   *   --- Top

   *   LiveEdit routine frames

   *   ---

   *   C frames of debug handler

   *   ---

   *   ...

   *   ---

   *      An internal frame that has n padding words:

   *      - any number of words as needed by code -- upper part of frame

   *      - padding size: a Smi storing n -- current size of padding

   *      - padding: n words filled with kPaddingValue in form of Smi

   *      - 3 context/type words of a regular InternalFrame

   *      - fp

   *   ---

   *      Topmost JavaScript frame

   *   ---

   *   ...

   *   --- Bottom

   */

  class FramePaddingLayout : public AllStatic {

   public:

    // Architecture-specific constant.

    static const bool kIsSupported;

    // A size of frame base including fp. Padding words starts right above

    // the base.

    static const int kFrameBaseSize = 4;

    // A number of words that should be reserved on stack for the LiveEdit use.

    // Normally equals 1. Stored on stack in form of Smi.

    static const int kInitialSize;

    // A value that padding words are filled with (in form of Smi). Going

    // bottom-top, the first word not having this value is a counter word.

    static const int kPaddingValue;

  };

 private:

  explicit Debug(Isolate* isolate);

  ~Debug();

  static bool CompileDebuggerScript(Isolate* isolate, int index);

  void ClearOneShot();

  void ActivateStepIn(StackFrame* frame);

  void ClearStepIn();

  void ActivateStepOut(StackFrame* frame);

  void ClearStepNext();

  // Returns whether the compile succeeded.

  void RemoveDebugInfo(Handle<DebugInfo> debug_info);

  void SetAfterBreakTarget(JavaScriptFrame* frame);

  Handle<Object> CheckBreakPoints(Handle<Object> break_point);

  bool CheckBreakPoint(Handle<Object> break_point_object);

  // Global handle to debug context where all the debugger JavaScript code is

  // loaded.

  Handle<Context> debug_context_;

  // Boolean state indicating whether any break points are set.

  bool has_break_points_;

  // Cache of all scripts in the heap.

  ScriptCache* script_cache_;

  // List of active debug info objects.

  DebugInfoListNode* debug_info_list_;

  bool disable_break_;

  bool break_on_exception_;

  bool break_on_uncaught_exception_;

  // Per-thread data.

  class ThreadLocal {

   public:

    // Counter for generating next break id.

    int break_count_;

    // Current break id.

    int break_id_;

    // Frame id for the frame of the current break.

    StackFrame::Id break_frame_id_;

    // Step action for last step performed.

    StepAction last_step_action_;

    // Source statement position from last step next action.

    int last_statement_position_;

    // Number of steps left to perform before debug event.

    int step_count_;

    // Frame pointer from last step next action.

    Address last_fp_;

    // Number of queued steps left to perform before debug event.

    int queued_step_count_;

    // Frame pointer for frame from which step in was performed.

    Address step_into_fp_;

    // Frame pointer for the frame where debugger should be called when current

    // step out action is completed.

    Address step_out_fp_;

    // Storage location for jump when exiting debug break calls.

    Address after_break_target_;

    // Stores the way how LiveEdit has patched the stack. It is used when

    // debugger returns control back to user script.

    FrameDropMode frame_drop_mode_;

    // Top debugger entry.

    EnterDebugger* debugger_entry_;

    // Pending interrupts scheduled while debugging.

    int pending_interrupts_;

    // When restarter frame is on stack, stores the address

    // of the pointer to function being restarted. Otherwise (most of the time)

    // stores NULL. This pointer is used with 'step in' implementation.

    Object** restarter_frame_function_pointer_;

  };

  // Storage location for registers when handling debug break calls

  JSCallerSavedBuffer registers_;

  ThreadLocal thread_local_;

  void ThreadInit();

  // Code to call for handling debug break on return.

  Code* debug_break_return_;

  // Code to call for handling debug break in debug break slots.

  Code* debug_break_slot_;

  Isolate* isolate_;

  friend class Isolate;

  DISALLOW_COPY_AND_ASSIGN(Debug);

};

DECLARE_RUNTIME_FUNCTION(Object*, Debug_Break);

// Message delivered to the message handler callback. This is either a debugger

// event or the response to a command.

class MessageImpl: public v8::Debug::Message {

 public:

  // Create a message object for a debug event.

  static MessageImpl NewEvent(DebugEvent event,

                              bool running,

                              Handle<JSObject> exec_state,

                              Handle<JSObject> event_data);

  // Create a message object for the response to a debug command.

  static MessageImpl NewResponse(DebugEvent event,

                                 bool running,

                                 Handle<JSObject> exec_state,

                                 Handle<JSObject> event_data,

                                 Handle<String> response_json,

                                 v8::Debug::ClientData* client_data);

  // Implementation of interface v8::Debug::Message.

  virtual bool IsEvent() const;

  virtual bool IsResponse() const;

  virtual DebugEvent GetEvent() const;

  virtual bool WillStartRunning() const;

  virtual v8::Handle<v8::Object> GetExecutionState() const;

  virtual v8::Handle<v8::Object> GetEventData() const;

  virtual v8::Handle<v8::String> GetJSON() const;

  virtual v8::Handle<v8::Context> GetEventContext() const;

  virtual v8::Debug::ClientData* GetClientData() const;

  virtual v8::Isolate* GetIsolate() const;

 private:

  MessageImpl(bool is_event,

              DebugEvent event,

              bool running,

              Handle<JSObject> exec_state,

              Handle<JSObject> event_data,

              Handle<String> response_json,

              v8::Debug::ClientData* client_data);

  bool is_event_;  // Does this message represent a debug event?

  DebugEvent event_;  // Debug event causing the break.

  bool running_;  // Will the VM start running after this event?

  Handle<JSObject> exec_state_;  // Current execution state.

  Handle<JSObject> event_data_;  // Data associated with the event.

  Handle<String> response_json_;  // Response JSON if message holds a response.

  v8::Debug::ClientData* client_data_;  // Client data passed with the request.

};

// Details of the debug event delivered to the debug event listener.

class EventDetailsImpl : public v8::Debug::EventDetails {

 public:

  EventDetailsImpl(DebugEvent event,

                   Handle<JSObject> exec_state,

                   Handle<JSObject> event_data,

                   Handle<Object> callback_data,

                   v8::Debug::ClientData* client_data);

  virtual DebugEvent GetEvent() const;

  virtual v8::Handle<v8::Object> GetExecutionState() const;

  virtual v8::Handle<v8::Object> GetEventData() const;

  virtual v8::Handle<v8::Context> GetEventContext() const;

  virtual v8::Handle<v8::Value> GetCallbackData() const;

  virtual v8::Debug::ClientData* GetClientData() const;

 private:

  DebugEvent event_;  // Debug event causing the break.

  Handle<JSObject> exec_state_;         // Current execution state.

  Handle<JSObject> event_data_;         // Data associated with the event.

  Handle<Object> callback_data_;        // User data passed with the callback

                                        // when it was registered.

  v8::Debug::ClientData* client_data_;  // Data passed to DebugBreakForCommand.

};

// Message send by user to v8 debugger or debugger output message.

// In addition to command text it may contain a pointer to some user data

// which are expected to be passed along with the command reponse to message

// handler.

class CommandMessage {

 public:

  static CommandMessage New(const Vector<uint16_t>& command,

                            v8::Debug::ClientData* data);

  CommandMessage();

  ~CommandMessage();

  // Deletes user data and disposes of the text.

  void Dispose();

  Vector<uint16_t> text() const { return text_; }

  v8::Debug::ClientData* client_data() const { return client_data_; }

 private:

  CommandMessage(const Vector<uint16_t>& text,

                 v8::Debug::ClientData* data);

  Vector<uint16_t> text_;

  v8::Debug::ClientData* client_data_;

};

// A Queue of CommandMessage objects.  A thread-safe version is

// LockingCommandMessageQueue, based on this class.

class CommandMessageQueue BASE_EMBEDDED {

 public:

  explicit CommandMessageQueue(int size);

  ~CommandMessageQueue();

  bool IsEmpty() const { return start_ == end_; }

  CommandMessage Get();

  void Put(const CommandMessage& message);

  void Clear() { start_ = end_ = 0; }  // Queue is empty after Clear().

 private:

  // Doubles the size of the message queue, and copies the messages.

  void Expand();

  CommandMessage* messages_;

  int start_;

  int end_;

  int size_;  // The size of the queue buffer.  Queue can hold size-1 messages.

};

class MessageDispatchHelperThread;

// LockingCommandMessageQueue is a thread-safe circular buffer of CommandMessage

// messages.  The message data is not managed by LockingCommandMessageQueue.

// Pointers to the data are passed in and out. Implemented by adding a

// Mutex to CommandMessageQueue.  Includes logging of all puts and gets.

class LockingCommandMessageQueue BASE_EMBEDDED {

 public:

  LockingCommandMessageQueue(Logger* logger, int size);

  bool IsEmpty() const;

  CommandMessage Get();

  void Put(const CommandMessage& message);

  void Clear();

 private:

  Logger* logger_;

  CommandMessageQueue queue_;

  mutable Mutex mutex_;

  DISALLOW_COPY_AND_ASSIGN(LockingCommandMessageQueue);

};

class Debugger {

 public:

  ~Debugger();

  void DebugRequest(const uint16_t* json_request, int length);

  Handle<Object> MakeJSObject(Vector<const char> constructor_name,

                              int argc,

                              Handle<Object> argv[],

                              bool* caught_exception);

  Handle<Object> MakeExecutionState(bool* caught_exception);

  Handle<Object> MakeBreakEvent(Handle<Object> exec_state,

                                Handle<Object> break_points_hit,

                                bool* caught_exception);

  Handle<Object> MakeExceptionEvent(Handle<Object> exec_state,

                                    Handle<Object> exception,

                                    bool uncaught,

                                    bool* caught_exception);

  Handle<Object> MakeNewFunctionEvent(Handle<Object> func,

                                      bool* caught_exception);

  Handle<Object> MakeCompileEvent(Handle<Script> script,

                                  bool before,

                                  bool* caught_exception);

  Handle<Object> MakeScriptCollectedEvent(int id,

                                          bool* caught_exception);

  void OnDebugBreak(Handle<Object> break_points_hit, bool auto_continue);

  void OnException(Handle<Object> exception, bool uncaught);

  void OnBeforeCompile(Handle<Script> script);

  enum AfterCompileFlags {

    NO_AFTER_COMPILE_FLAGS,

    SEND_WHEN_DEBUGGING

  };

  void OnAfterCompile(Handle<Script> script,

                      AfterCompileFlags after_compile_flags);

  void OnScriptCollected(int id);

  void ProcessDebugEvent(v8::DebugEvent event,

                         Handle<JSObject> event_data,

                         bool auto_continue);

  void NotifyMessageHandler(v8::DebugEvent event,

                            Handle<JSObject> exec_state,

                            Handle<JSObject> event_data,

                            bool auto_continue);

  void SetEventListener(Handle<Object> callback, Handle<Object> data);

  void SetMessageHandler(v8::Debug::MessageHandler2 handler);

  void SetHostDispatchHandler(v8::Debug::HostDispatchHandler handler,

                              TimeDelta period);

  void SetDebugMessageDispatchHandler(

      v8::Debug::DebugMessageDispatchHandler handler,

      bool provide_locker);

  // Invoke the message handler function.

  void InvokeMessageHandler(MessageImpl message);

  // Add a debugger command to the command queue.

  void ProcessCommand(Vector<const uint16_t> command,

                      v8::Debug::ClientData* client_data = NULL);

  // Check whether there are commands in the command queue.

  bool HasCommands();

  // Enqueue a debugger command to the command queue for event listeners.

  void EnqueueDebugCommand(v8::Debug::ClientData* client_data = NULL);

  Handle<Object> Call(Handle<JSFunction> fun,

                      Handle<Object> data,

                      bool* pending_exception);

  // Start the debugger agent listening on the provided port.

  bool StartAgent(const char* name, int port,

                  bool wait_for_connection = false);

  // Stop the debugger agent.

  void StopAgent();

  // Blocks until the agent has started listening for connections

  void WaitForAgent();

  void CallMessageDispatchHandler();

  Handle<Context> GetDebugContext();

  // Unload the debugger if possible. Only called when no debugger is currently

  // active.

  void UnloadDebugger();

  friend void ForceUnloadDebugger();  // In test-debug.cc

  inline bool EventActive(v8::DebugEvent event) {

    LockGuard<RecursiveMutex> lock_guard(debugger_access_);

    // Check whether the message handler was been cleared.

    if (debugger_unload_pending_) {

      if (isolate_->debug()->debugger_entry() == NULL) {

        UnloadDebugger();

      }

    }

    if (((event == v8::BeforeCompile) || (event == v8::AfterCompile)) &&

        !FLAG_debug_compile_events) {

      return false;

    } else if ((event == v8::ScriptCollected) &&

               !FLAG_debug_script_collected_events) {

      return false;

    }

    // Currently argument event is not used.

    return !compiling_natives_ && Debugger::IsDebuggerActive();

  }

  void set_compiling_natives(bool compiling_natives) {

    compiling_natives_ = compiling_natives;

  }

  bool compiling_natives() const { return compiling_natives_; }

  void set_loading_debugger(bool v) { is_loading_debugger_ = v; }

  bool is_loading_debugger() const { return is_loading_debugger_; }

  void set_live_edit_enabled(bool v) { live_edit_enabled_ = v; }

  bool live_edit_enabled() const {

    return FLAG_enable_liveedit && live_edit_enabled_ ;

  }

  void set_force_debugger_active(bool force_debugger_active) {

    force_debugger_active_ = force_debugger_active;

  }

  bool force_debugger_active() const { return force_debugger_active_; }

  bool IsDebuggerActive();

 private:

  explicit Debugger(Isolate* isolate);

  void CallEventCallback(v8::DebugEvent event,

                         Handle<Object> exec_state,

                         Handle<Object> event_data,

                         v8::Debug::ClientData* client_data);

  void CallCEventCallback(v8::DebugEvent event,

                          Handle<Object> exec_state,

                          Handle<Object> event_data,

                          v8::Debug::ClientData* client_data);

  void CallJSEventCallback(v8::DebugEvent event,

                           Handle<Object> exec_state,

                           Handle<Object> event_data);

  void ListenersChanged();

  RecursiveMutex* debugger_access_;  // Mutex guarding debugger variables.

  Handle<Object> event_listener_;  // Global handle to listener.

  Handle<Object> event_listener_data_;

  bool compiling_natives_;  // Are we compiling natives?

  bool is_loading_debugger_;  // Are we loading the debugger?

  bool live_edit_enabled_;  // Enable LiveEdit.

  bool never_unload_debugger_;  // Can we unload the debugger?

  bool force_debugger_active_;  // Activate debugger without event listeners.

  v8::Debug::MessageHandler2 message_handler_;

  bool debugger_unload_pending_;  // Was message handler cleared?

  v8::Debug::HostDispatchHandler host_dispatch_handler_;

  Mutex dispatch_handler_access_;  // Mutex guarding dispatch handler.

  v8::Debug::DebugMessageDispatchHandler debug_message_dispatch_handler_;

  MessageDispatchHelperThread* message_dispatch_helper_thread_;

  TimeDelta host_dispatch_period_;

  DebuggerAgent* agent_;

  static const int kQueueInitialSize = 4;

  LockingCommandMessageQueue command_queue_;

  Semaphore command_received_;  // Signaled for each command received.

  LockingCommandMessageQueue event_command_queue_;

  Isolate* isolate_;

  friend class EnterDebugger;

  friend class Isolate;

  DISALLOW_COPY_AND_ASSIGN(Debugger);

};

// This class is used for entering the debugger. Create an instance in the stack

// to enter the debugger. This will set the current break state, make sure the

// debugger is loaded and switch to the debugger context. If the debugger for

// some reason could not be entered FailedToEnter will return true.

class EnterDebugger BASE_EMBEDDED {

 public:

  explicit EnterDebugger(Isolate* isolate);

  ~EnterDebugger();

  // Check whether the debugger could be entered.

  inline bool FailedToEnter() { return load_failed_; }

  // Check whether there are any JavaScript frames on the stack.

  inline bool HasJavaScriptFrames() { return has_js_frames_; }

  // Get the active context from before entering the debugger.

  inline Handle<Context> GetContext() { return save_.context(); }

 private:

  Isolate* isolate_;

  EnterDebugger* prev_;  // Previous debugger entry if entered recursively.

  JavaScriptFrameIterator it_;

  const bool has_js_frames_;  // Were there any JavaScript frames?

  StackFrame::Id break_frame_id_;  // Previous break frame id.

  int break_id_;  // Previous break id.

  bool load_failed_;  // Did the debugger fail to load?

  SaveContext save_;  // Saves previous context.

};

// Stack allocated class for disabling break.

class DisableBreak BASE_EMBEDDED {

 public:

  explicit DisableBreak(Isolate* isolate, bool disable_break)

    : isolate_(isolate) {

    prev_disable_break_ = isolate_->debug()->disable_break();

    isolate_->debug()->set_disable_break(disable_break);

  }

  ~DisableBreak() {

    isolate_->debug()->set_disable_break(prev_disable_break_);

  }

 private:

  Isolate* isolate_;

  // The previous state of the disable break used to restore the value when this

  // object is destructed.

  bool prev_disable_break_;

};

// Debug_Address encapsulates the Address pointers used in generating debug

// code.

class Debug_Address {

 public:

  explicit Debug_Address(Debug::AddressId id) : id_(id) { }

  static Debug_Address AfterBreakTarget() {

    return Debug_Address(Debug::k_after_break_target_address);

  }

  static Debug_Address DebugBreakReturn() {

    return Debug_Address(Debug::k_debug_break_return_address);

  }

  static Debug_Address RestarterFrameFunctionPointer() {

    return Debug_Address(Debug::k_restarter_frame_function_pointer);

  }

  Address address(Isolate* isolate) const {

    Debug* debug = isolate->debug();

    switch (id_) {

      case Debug::k_after_break_target_address:

        return reinterpret_cast<Address>(debug->after_break_target_address());

      case Debug::k_debug_break_return_address:

        return reinterpret_cast<Address>(debug->debug_break_return_address());

      case Debug::k_debug_break_slot_address:

        return reinterpret_cast<Address>(debug->debug_break_slot_address());

      case Debug::k_restarter_frame_function_pointer:

        return reinterpret_cast<Address>(

            debug->restarter_frame_function_pointer_address());

      default:

        UNREACHABLE();

        return NULL;

    }

  }

 private:

  Debug::AddressId id_;

};

// The optional thread that Debug Agent may use to temporary call V8 to process

// pending debug requests if debuggee is not running V8 at the moment.

// Techincally it does not call V8 itself, rather it asks embedding program

// to do this via v8::Debug::HostDispatchHandler

class MessageDispatchHelperThread: public Thread {

 public:

  explicit MessageDispatchHelperThread(Isolate* isolate);

  ~MessageDispatchHelperThread() {}

  void Schedule();

 private:

  void Run();

  Isolate* isolate_;

  Semaphore sem_;

  Mutex mutex_;

  bool already_signalled_;

  DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);

};

} }  // namespace v8::internal

#endif  // ENABLE_DEBUGGER_SUPPORT

#endif  // V8_DEBUG_H_