debug.h.svn-base

Google浏览器V8内核代码

   public:
    // 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_;

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

    // Storage location for jump when exiting debug break calls.
    Address after_break_target_;
  };

  // Storage location for registers when handling debug break calls
  static JSCallerSavedBuffer registers_;
  static ThreadLocal thread_local_;
  static void ThreadInit();

  // Code object for debug break return entry code.
  static Code* debug_break_return_entry_;

  // Code to call for handling debug break on return.
  static Code* debug_break_return_;

  DISALLOW_COPY_AND_ASSIGN(Debug);
};


class DebugMessageThread;

class Debugger {
 public:
  static void DebugRequest(const uint16_t* json_request, int length);

  static Handle<Object> MakeJSObject(Vector<const char> constructor_name,
                                     int argc, Object*** argv,
                                     bool* caught_exception);
  static Handle<Object> MakeExecutionState(bool* caught_exception);
  static Handle<Object> MakeBreakEvent(Handle<Object> exec_state,
                                       Handle<Object> break_points_hit,
                                       bool* caught_exception);
  static Handle<Object> MakeExceptionEvent(Handle<Object> exec_state,
                                           Handle<Object> exception,
                                           bool uncaught,
                                           bool* caught_exception);
  static Handle<Object> MakeNewFunctionEvent(Handle<Object> func,
                                             bool* caught_exception);
  static Handle<Object> MakeCompileEvent(Handle<Script> script,
                                         Handle<Object> script_function,
                                         bool* caught_exception);
  static Handle<String> ProcessRequest(Handle<Object> exec_state,
                                       Handle<Object> request,
                                       bool stopped);
  static void OnDebugBreak(Handle<Object> break_points_hit);
  static void OnException(Handle<Object> exception, bool uncaught);
  static void OnBeforeCompile(Handle<Script> script);
  static void OnAfterCompile(Handle<Script> script,
                           Handle<JSFunction> fun);
  static void OnNewFunction(Handle<JSFunction> fun);
  static void ProcessDebugEvent(v8::DebugEvent event,
                                Handle<Object> event_data);
  static void SetMessageHandler(v8::DebugMessageHandler handler, void* data);
  static void SendMessage(Vector<uint16_t> message);
  static void ProcessCommand(Vector<const uint16_t> command);
  static void UpdateActiveDebugger();
  inline static bool EventActive(v8::DebugEvent event) {
    // Currently argument event is not used.
    return !Debugger::compiling_natives_ && Debugger::debugger_active_;
  }

  static void set_debugger_active(bool debugger_active) {
    Debugger::debugger_active_ = debugger_active;
  }
  static bool debugger_active() { return Debugger::debugger_active_; }
  static void set_compiling_natives(bool compiling_natives) {
    Debugger::compiling_natives_ = compiling_natives;
  }
  static bool compiling_natives() { return Debugger::compiling_natives_; }
  static void set_loading_debugger(bool v) { is_loading_debugger_ = v; }
  static bool is_loading_debugger() { return Debugger::is_loading_debugger_; }

 private:
  static bool debugger_active_;  // Are there any active debugger?
  static bool compiling_natives_;  // Are we compiling natives?
  static bool is_loading_debugger_;  // Are we loading the debugger?
  static DebugMessageThread* message_thread_;
  static v8::DebugMessageHandler debug_message_handler_;
  static void* debug_message_handler_data_;
};


// A Queue of Vector<uint16_t> objects.  A thread-safe version is
// LockingMessageQueue, based on this class.
class MessageQueue BASE_EMBEDDED {
 public:
  explicit MessageQueue(int size);
  ~MessageQueue();
  bool IsEmpty() const { return start_ == end_; }
  Vector<uint16_t> Get();
  void Put(const Vector<uint16_t>& 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();

  Vector<uint16_t>* messages_;
  int start_;
  int end_;
  int size_;  // The size of the queue buffer.  Queue can hold size-1 messages.
};


// LockingMessageQueue is a thread-safe circular buffer of Vector<uint16_t>
// messages.  The message data is not managed by LockingMessageQueue.
// Pointers to the data are passed in and out. Implemented by adding a
// Mutex to MessageQueue.  Includes logging of all puts and gets.
class LockingMessageQueue BASE_EMBEDDED {
 public:
  explicit LockingMessageQueue(int size);
  ~LockingMessageQueue();
  bool IsEmpty() const;
  Vector<uint16_t> Get();
  void Put(const Vector<uint16_t>& message);
  void Clear();
 private:
  MessageQueue queue_;
  Mutex* lock_;
  DISALLOW_COPY_AND_ASSIGN(LockingMessageQueue);
};


/* This class is the data for a running thread that serializes
 * event messages and command processing for the debugger.
 * All uncommented methods are called only from this message thread.
 */
class DebugMessageThread: public Thread {
 public:
  DebugMessageThread();  // Called from API thread.
  virtual ~DebugMessageThread();  // Never called.
  // Called by V8 thread.  Reports events from V8 VM.
  // Also handles command processing in stopped state of V8,
  // when host_running_ is false.
  void DebugEvent(v8::DebugEvent,
                  Handle<Object> exec_state,
                  Handle<Object> event_data);
  // Puts event on the output queue.  Called by V8.
  // This is where V8 hands off
  // processing of the event to the DebugMessageThread thread,
  // which forwards it to the debug_message_handler set by the API.
  void SendMessage(Vector<uint16_t> event_json);
  // Formats an event into JSON, and calls SendMessage.
  void SetEventJSONFromEvent(Handle<Object> event_data);
  // Puts a command coming from the public API on the queue.  Called
  // by the API client thread.  This is where the API client hands off
  // processing of the command to the DebugMessageThread thread.
  void ProcessCommand(Vector<uint16_t> command);
  void OnDebuggerInactive();

  // Main function of DebugMessageThread thread.
  void Run();

  bool host_running_;  // Is the debugging host running or stopped?
  Semaphore* command_received_;  // Non-zero when command queue is non-empty.
  Semaphore* message_received_;  // Exactly equal to message queue length.
 private:
  bool TwoByteEqualsAscii(Vector<uint16_t> two_byte, const char* ascii);

  static const int kQueueInitialSize = 4;
  LockingMessageQueue command_queue_;
  LockingMessageQueue message_queue_;
  DISALLOW_COPY_AND_ASSIGN(DebugMessageThread);
};


// Helper class to support saving/restoring the top break frame id.
class SaveBreakFrame {
 public:
  SaveBreakFrame() : set_(!it_.done()) {
    if (set_) {
      // Store the previous break is and frame id.
      break_id_ = Top::break_id();
      break_frame_id_ = Top::break_frame_id();

      // Create the new break info.
      Top::new_break(it_.frame()->id());
    }
  }

  ~SaveBreakFrame() {
    if (set_) {
      // restore to the previous break state.
      Top::set_break(break_frame_id_, break_id_);
    }
  }

 private:
  JavaScriptFrameIterator it_;
  const bool set_;  // Was the break actually set?
  StackFrame::Id break_frame_id_;  // Previous break frame id.
  int break_id_;  // Previous break id.
};


class EnterDebuggerContext BASE_EMBEDDED {
 public:
  // Enter the debugger by storing the previous top context and setting the
  // current top context to the debugger context.
  EnterDebuggerContext()  {
    // NOTE the member variable save which saves the previous context before
    // this change.
    Top::set_context(*Debug::debug_context());
    Top::set_security_context(*Debug::debug_context());
  }

 private:
  SaveContext save;
};


// Stack allocated class for disabling break.
class DisableBreak BASE_EMBEDDED {
 public:
  // Enter the debugger by storing the previous top context and setting the
  // current top context to the debugger context.
  explicit DisableBreak(bool disable_break)  {
    prev_disable_break_ = Debug::disable_break();
    Debug::set_disable_break(disable_break);
  }
  ~DisableBreak() {
    Debug::set_disable_break(prev_disable_break_);
  }

 private:
  // 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:
  Debug_Address(Debug::AddressId id, int reg = 0)
    : id_(id), reg_(reg) {
    ASSERT(reg == 0 || id == Debug::k_register_address);
  }

  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 Register(int reg) {
    return Debug_Address(Debug::k_register_address, reg);
  }

  Address address() const {
    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_register_address:
        return reinterpret_cast<Address>(Debug::register_address(reg_));
      default:
        UNREACHABLE();
        return NULL;
    }
  }
 private:
  Debug::AddressId id_;
  int reg_;
};


} }  // namespace v8::internal

#endif  // V8_V8_DEBUG_H_