1// Copyright 2012 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_DEBUG_DEBUG_H_
6#define V8_DEBUG_DEBUG_H_
7
8#include "src/allocation.h"
9#include "src/arguments.h"
10#include "src/assembler.h"
11#include "src/base/atomicops.h"
12#include "src/base/platform/platform.h"
13#include "src/debug/liveedit.h"
14#include "src/execution.h"
15#include "src/factory.h"
16#include "src/flags.h"
17#include "src/frames.h"
18#include "src/hashmap.h"
19#include "src/runtime/runtime.h"
20#include "src/string-stream.h"
21#include "src/v8threads.h"
22
23#include "include/v8-debug.h"
24
25namespace v8 {
26namespace internal {
27
28
29// Forward declarations.
30class DebugScope;
31
32
33// Step actions. NOTE: These values are in macros.py as well.
34enum StepAction : int8_t {
35  StepNone = -1,  // Stepping not prepared.
36  StepOut = 0,    // Step out of the current function.
37  StepNext = 1,   // Step to the next statement in the current function.
38  StepIn = 2,     // Step into new functions invoked or the next statement
39                  // in the current function.
40  StepFrame = 3   // Step into a new frame or return to previous frame.
41};
42
43
44// Type of exception break. NOTE: These values are in macros.py as well.
45enum ExceptionBreakType {
46  BreakException = 0,
47  BreakUncaughtException = 1
48};
49
50
51// Type of exception break.
52enum BreakLocatorType { ALL_BREAK_LOCATIONS, CALLS_AND_RETURNS };
53
54
55// The different types of breakpoint position alignments.
56// Must match Debug.BreakPositionAlignment in debug.js
57enum BreakPositionAlignment {
58  STATEMENT_ALIGNED = 0,
59  BREAK_POSITION_ALIGNED = 1
60};
61
62
63class BreakLocation {
64 public:
65  // Find the break point at the supplied address, or the closest one before
66  // the address.
67  static BreakLocation FromAddress(Handle<DebugInfo> debug_info, Address pc);
68
69  static void FromAddressSameStatement(Handle<DebugInfo> debug_info, Address pc,
70                                       List<BreakLocation>* result_out);
71
72  static BreakLocation FromPosition(Handle<DebugInfo> debug_info, int position,
73                                    BreakPositionAlignment alignment);
74
75  bool IsDebugBreak() const;
76
77  inline bool IsReturn() const {
78    return RelocInfo::IsDebugBreakSlotAtReturn(rmode_);
79  }
80  inline bool IsCall() const {
81    return RelocInfo::IsDebugBreakSlotAtCall(rmode_);
82  }
83  inline bool HasBreakPoint() const {
84    return debug_info_->HasBreakPoint(pc_offset_);
85  }
86
87  Handle<Object> BreakPointObjects() const;
88
89  void SetBreakPoint(Handle<Object> break_point_object);
90  void ClearBreakPoint(Handle<Object> break_point_object);
91
92  void SetOneShot();
93  void ClearOneShot();
94
95
96  inline RelocInfo rinfo() const {
97    return RelocInfo(debug_info_->GetIsolate(), pc(), rmode(), data_, code());
98  }
99
100  inline int position() const { return position_; }
101  inline int statement_position() const { return statement_position_; }
102
103  inline Address pc() const { return code()->entry() + pc_offset_; }
104
105  inline RelocInfo::Mode rmode() const { return rmode_; }
106
107  inline Code* code() const { return debug_info_->code(); }
108
109 private:
110  BreakLocation(Handle<DebugInfo> debug_info, RelocInfo* rinfo, int position,
111                int statement_position);
112
113  class Iterator {
114   public:
115    Iterator(Handle<DebugInfo> debug_info, BreakLocatorType type);
116
117    BreakLocation GetBreakLocation() {
118      return BreakLocation(debug_info_, rinfo(), position(),
119                           statement_position());
120    }
121
122    inline bool Done() const { return reloc_iterator_.done(); }
123    void Next();
124
125    void SkipTo(int count) {
126      while (count-- > 0) Next();
127    }
128
129    inline RelocInfo::Mode rmode() { return reloc_iterator_.rinfo()->rmode(); }
130    inline RelocInfo* rinfo() { return reloc_iterator_.rinfo(); }
131    inline Address pc() { return rinfo()->pc(); }
132    int break_index() const { return break_index_; }
133    inline int position() const { return position_; }
134    inline int statement_position() const { return statement_position_; }
135
136   private:
137    static int GetModeMask(BreakLocatorType type);
138
139    Handle<DebugInfo> debug_info_;
140    RelocIterator reloc_iterator_;
141    int break_index_;
142    int position_;
143    int statement_position_;
144
145    DisallowHeapAllocation no_gc_;
146
147    DISALLOW_COPY_AND_ASSIGN(Iterator);
148  };
149
150  friend class Debug;
151
152  static int BreakIndexFromAddress(Handle<DebugInfo> debug_info, Address pc);
153
154  void SetDebugBreak();
155  void ClearDebugBreak();
156
157  inline bool IsDebuggerStatement() const {
158    return RelocInfo::IsDebuggerStatement(rmode_);
159  }
160  inline bool IsDebugBreakSlot() const {
161    return RelocInfo::IsDebugBreakSlot(rmode_);
162  }
163
164  Handle<DebugInfo> debug_info_;
165  int pc_offset_;
166  RelocInfo::Mode rmode_;
167  intptr_t data_;
168  int position_;
169  int statement_position_;
170};
171
172
173// Linked list holding debug info objects. The debug info objects are kept as
174// weak handles to avoid a debug info object to keep a function alive.
175class DebugInfoListNode {
176 public:
177  explicit DebugInfoListNode(DebugInfo* debug_info);
178  ~DebugInfoListNode();
179
180  DebugInfoListNode* next() { return next_; }
181  void set_next(DebugInfoListNode* next) { next_ = next; }
182  Handle<DebugInfo> debug_info() { return Handle<DebugInfo>(debug_info_); }
183
184 private:
185  // Global (weak) handle to the debug info object.
186  DebugInfo** debug_info_;
187
188  // Next pointer for linked list.
189  DebugInfoListNode* next_;
190};
191
192
193
194// Message delivered to the message handler callback. This is either a debugger
195// event or the response to a command.
196class MessageImpl: public v8::Debug::Message {
197 public:
198  // Create a message object for a debug event.
199  static MessageImpl NewEvent(DebugEvent event,
200                              bool running,
201                              Handle<JSObject> exec_state,
202                              Handle<JSObject> event_data);
203
204  // Create a message object for the response to a debug command.
205  static MessageImpl NewResponse(DebugEvent event,
206                                 bool running,
207                                 Handle<JSObject> exec_state,
208                                 Handle<JSObject> event_data,
209                                 Handle<String> response_json,
210                                 v8::Debug::ClientData* client_data);
211
212  // Implementation of interface v8::Debug::Message.
213  virtual bool IsEvent() const;
214  virtual bool IsResponse() const;
215  virtual DebugEvent GetEvent() const;
216  virtual bool WillStartRunning() const;
217  virtual v8::Local<v8::Object> GetExecutionState() const;
218  virtual v8::Local<v8::Object> GetEventData() const;
219  virtual v8::Local<v8::String> GetJSON() const;
220  virtual v8::Local<v8::Context> GetEventContext() const;
221  virtual v8::Debug::ClientData* GetClientData() const;
222  virtual v8::Isolate* GetIsolate() const;
223
224 private:
225  MessageImpl(bool is_event,
226              DebugEvent event,
227              bool running,
228              Handle<JSObject> exec_state,
229              Handle<JSObject> event_data,
230              Handle<String> response_json,
231              v8::Debug::ClientData* client_data);
232
233  bool is_event_;  // Does this message represent a debug event?
234  DebugEvent event_;  // Debug event causing the break.
235  bool running_;  // Will the VM start running after this event?
236  Handle<JSObject> exec_state_;  // Current execution state.
237  Handle<JSObject> event_data_;  // Data associated with the event.
238  Handle<String> response_json_;  // Response JSON if message holds a response.
239  v8::Debug::ClientData* client_data_;  // Client data passed with the request.
240};
241
242
243// Details of the debug event delivered to the debug event listener.
244class EventDetailsImpl : public v8::Debug::EventDetails {
245 public:
246  EventDetailsImpl(DebugEvent event,
247                   Handle<JSObject> exec_state,
248                   Handle<JSObject> event_data,
249                   Handle<Object> callback_data,
250                   v8::Debug::ClientData* client_data);
251  virtual DebugEvent GetEvent() const;
252  virtual v8::Local<v8::Object> GetExecutionState() const;
253  virtual v8::Local<v8::Object> GetEventData() const;
254  virtual v8::Local<v8::Context> GetEventContext() const;
255  virtual v8::Local<v8::Value> GetCallbackData() const;
256  virtual v8::Debug::ClientData* GetClientData() const;
257 private:
258  DebugEvent event_;  // Debug event causing the break.
259  Handle<JSObject> exec_state_;         // Current execution state.
260  Handle<JSObject> event_data_;         // Data associated with the event.
261  Handle<Object> callback_data_;        // User data passed with the callback
262                                        // when it was registered.
263  v8::Debug::ClientData* client_data_;  // Data passed to DebugBreakForCommand.
264};
265
266
267// Message send by user to v8 debugger or debugger output message.
268// In addition to command text it may contain a pointer to some user data
269// which are expected to be passed along with the command reponse to message
270// handler.
271class CommandMessage {
272 public:
273  static CommandMessage New(const Vector<uint16_t>& command,
274                            v8::Debug::ClientData* data);
275  CommandMessage();
276
277  // Deletes user data and disposes of the text.
278  void Dispose();
279  Vector<uint16_t> text() const { return text_; }
280  v8::Debug::ClientData* client_data() const { return client_data_; }
281 private:
282  CommandMessage(const Vector<uint16_t>& text,
283                 v8::Debug::ClientData* data);
284
285  Vector<uint16_t> text_;
286  v8::Debug::ClientData* client_data_;
287};
288
289
290// A Queue of CommandMessage objects.  A thread-safe version is
291// LockingCommandMessageQueue, based on this class.
292class CommandMessageQueue BASE_EMBEDDED {
293 public:
294  explicit CommandMessageQueue(int size);
295  ~CommandMessageQueue();
296  bool IsEmpty() const { return start_ == end_; }
297  CommandMessage Get();
298  void Put(const CommandMessage& message);
299  void Clear() { start_ = end_ = 0; }  // Queue is empty after Clear().
300 private:
301  // Doubles the size of the message queue, and copies the messages.
302  void Expand();
303
304  CommandMessage* messages_;
305  int start_;
306  int end_;
307  int size_;  // The size of the queue buffer.  Queue can hold size-1 messages.
308};
309
310
311// LockingCommandMessageQueue is a thread-safe circular buffer of CommandMessage
312// messages.  The message data is not managed by LockingCommandMessageQueue.
313// Pointers to the data are passed in and out. Implemented by adding a
314// Mutex to CommandMessageQueue.  Includes logging of all puts and gets.
315class LockingCommandMessageQueue BASE_EMBEDDED {
316 public:
317  LockingCommandMessageQueue(Logger* logger, int size);
318  bool IsEmpty() const;
319  CommandMessage Get();
320  void Put(const CommandMessage& message);
321  void Clear();
322 private:
323  Logger* logger_;
324  CommandMessageQueue queue_;
325  mutable base::Mutex mutex_;
326  DISALLOW_COPY_AND_ASSIGN(LockingCommandMessageQueue);
327};
328
329
330class DebugFeatureTracker {
331 public:
332  enum Feature {
333    kActive = 1,
334    kBreakPoint = 2,
335    kStepping = 3,
336    kHeapSnapshot = 4,
337    kAllocationTracking = 5,
338    kProfiler = 6,
339    kLiveEdit = 7,
340  };
341
342  explicit DebugFeatureTracker(Isolate* isolate)
343      : isolate_(isolate), bitfield_(0) {}
344  void Track(Feature feature);
345
346 private:
347  Isolate* isolate_;
348  uint32_t bitfield_;
349};
350
351
352// This class contains the debugger support. The main purpose is to handle
353// setting break points in the code.
354//
355// This class controls the debug info for all functions which currently have
356// active breakpoints in them. This debug info is held in the heap root object
357// debug_info which is a FixedArray. Each entry in this list is of class
358// DebugInfo.
359class Debug {
360 public:
361  // Debug event triggers.
362  void OnDebugBreak(Handle<Object> break_points_hit, bool auto_continue);
363
364  void OnThrow(Handle<Object> exception);
365  void OnPromiseReject(Handle<JSObject> promise, Handle<Object> value);
366  void OnCompileError(Handle<Script> script);
367  void OnBeforeCompile(Handle<Script> script);
368  void OnAfterCompile(Handle<Script> script);
369  void OnPromiseEvent(Handle<JSObject> data);
370  void OnAsyncTaskEvent(Handle<JSObject> data);
371
372  // API facing.
373  void SetEventListener(Handle<Object> callback, Handle<Object> data);
374  void SetMessageHandler(v8::Debug::MessageHandler handler);
375  void EnqueueCommandMessage(Vector<const uint16_t> command,
376                             v8::Debug::ClientData* client_data = NULL);
377  MUST_USE_RESULT MaybeHandle<Object> Call(Handle<Object> fun,
378                                           Handle<Object> data);
379  Handle<Context> GetDebugContext();
380  void HandleDebugBreak();
381  void ProcessDebugMessages(bool debug_command_only);
382
383  // Internal logic
384  bool Load();
385  void Break(Arguments args, JavaScriptFrame*);
386  void SetAfterBreakTarget(JavaScriptFrame* frame);
387
388  // Scripts handling.
389  Handle<FixedArray> GetLoadedScripts();
390
391  // Break point handling.
392  bool SetBreakPoint(Handle<JSFunction> function,
393                     Handle<Object> break_point_object,
394                     int* source_position);
395  bool SetBreakPointForScript(Handle<Script> script,
396                              Handle<Object> break_point_object,
397                              int* source_position,
398                              BreakPositionAlignment alignment);
399  void ClearBreakPoint(Handle<Object> break_point_object);
400  void ClearAllBreakPoints();
401  void FloodWithOneShot(Handle<JSFunction> function,
402                        BreakLocatorType type = ALL_BREAK_LOCATIONS);
403  void ChangeBreakOnException(ExceptionBreakType type, bool enable);
404  bool IsBreakOnException(ExceptionBreakType type);
405
406  // Stepping handling.
407  void PrepareStep(StepAction step_action);
408  void PrepareStepIn(Handle<JSFunction> function);
409  void PrepareStepOnThrow();
410  void ClearStepping();
411  void ClearStepOut();
412  void EnableStepIn();
413
414  void GetStepinPositions(JavaScriptFrame* frame, StackFrame::Id frame_id,
415                          List<int>* results_out);
416
417  bool PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared);
418
419  // Returns whether the operation succeeded. Compilation can only be triggered
420  // if a valid closure is passed as the second argument, otherwise the shared
421  // function needs to be compiled already.
422  bool EnsureDebugInfo(Handle<SharedFunctionInfo> shared,
423                       Handle<JSFunction> function);
424  void CreateDebugInfo(Handle<SharedFunctionInfo> shared);
425  static Handle<DebugInfo> GetDebugInfo(Handle<SharedFunctionInfo> shared);
426
427  template <typename C>
428  bool CompileToRevealInnerFunctions(C* compilable);
429
430  // This function is used in FunctionNameUsing* tests.
431  Handle<Object> FindSharedFunctionInfoInScript(Handle<Script> script,
432                                                int position);
433
434  static Handle<Object> GetSourceBreakLocations(
435      Handle<SharedFunctionInfo> shared,
436      BreakPositionAlignment position_aligment);
437
438  // Check whether a global object is the debug global object.
439  bool IsDebugGlobal(JSGlobalObject* global);
440
441  // Check whether this frame is just about to return.
442  bool IsBreakAtReturn(JavaScriptFrame* frame);
443
444  // Support for LiveEdit
445  void FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,
446                             LiveEdit::FrameDropMode mode);
447
448  // Threading support.
449  char* ArchiveDebug(char* to);
450  char* RestoreDebug(char* from);
451  static int ArchiveSpacePerThread();
452  void FreeThreadResources() { }
453
454  // Record function from which eval was called.
455  static void RecordEvalCaller(Handle<Script> script);
456
457  bool CheckExecutionState(int id) {
458    return is_active() && !debug_context().is_null() && break_id() != 0 &&
459           break_id() == id;
460  }
461
462  // Flags and states.
463  DebugScope* debugger_entry() {
464    return reinterpret_cast<DebugScope*>(
465        base::NoBarrier_Load(&thread_local_.current_debug_scope_));
466  }
467  inline Handle<Context> debug_context() { return debug_context_; }
468
469  void set_live_edit_enabled(bool v) { live_edit_enabled_ = v; }
470  bool live_edit_enabled() const {
471    return FLAG_enable_liveedit && live_edit_enabled_;
472  }
473
474  inline bool is_active() const { return is_active_; }
475  inline bool is_loaded() const { return !debug_context_.is_null(); }
476  inline bool in_debug_scope() const {
477    return !!base::NoBarrier_Load(&thread_local_.current_debug_scope_);
478  }
479  void set_break_points_active(bool v) { break_points_active_ = v; }
480  bool break_points_active() const { return break_points_active_; }
481
482  StackFrame::Id break_frame_id() { return thread_local_.break_frame_id_; }
483  int break_id() { return thread_local_.break_id_; }
484
485  // Support for embedding into generated code.
486  Address is_active_address() {
487    return reinterpret_cast<Address>(&is_active_);
488  }
489
490  Address after_break_target_address() {
491    return reinterpret_cast<Address>(&after_break_target_);
492  }
493
494  Address step_in_enabled_address() {
495    return reinterpret_cast<Address>(&thread_local_.step_in_enabled_);
496  }
497
498  StepAction last_step_action() { return thread_local_.last_step_action_; }
499
500  DebugFeatureTracker* feature_tracker() { return &feature_tracker_; }
501
502 private:
503  explicit Debug(Isolate* isolate);
504
505  void UpdateState();
506  void Unload();
507  void SetNextBreakId() {
508    thread_local_.break_id_ = ++thread_local_.break_count_;
509  }
510
511  // Check whether there are commands in the command queue.
512  inline bool has_commands() const { return !command_queue_.IsEmpty(); }
513  inline bool ignore_events() const { return is_suppressed_ || !is_active_; }
514  inline bool break_disabled() const {
515    return break_disabled_ || in_debug_event_listener_;
516  }
517
518  void OnException(Handle<Object> exception, Handle<Object> promise);
519
520  // Constructors for debug event objects.
521  MUST_USE_RESULT MaybeHandle<Object> MakeExecutionState();
522  MUST_USE_RESULT MaybeHandle<Object> MakeBreakEvent(
523      Handle<Object> break_points_hit);
524  MUST_USE_RESULT MaybeHandle<Object> MakeExceptionEvent(
525      Handle<Object> exception,
526      bool uncaught,
527      Handle<Object> promise);
528  MUST_USE_RESULT MaybeHandle<Object> MakeCompileEvent(
529      Handle<Script> script, v8::DebugEvent type);
530  MUST_USE_RESULT MaybeHandle<Object> MakePromiseEvent(
531      Handle<JSObject> promise_event);
532  MUST_USE_RESULT MaybeHandle<Object> MakeAsyncTaskEvent(
533      Handle<JSObject> task_event);
534
535  // Mirror cache handling.
536  void ClearMirrorCache();
537
538  MaybeHandle<Object> PromiseHasUserDefinedRejectHandler(
539      Handle<JSObject> promise);
540
541  void CallEventCallback(v8::DebugEvent event,
542                         Handle<Object> exec_state,
543                         Handle<Object> event_data,
544                         v8::Debug::ClientData* client_data);
545  void ProcessCompileEvent(v8::DebugEvent event, Handle<Script> script);
546  void ProcessDebugEvent(v8::DebugEvent event,
547                         Handle<JSObject> event_data,
548                         bool auto_continue);
549  void NotifyMessageHandler(v8::DebugEvent event,
550                            Handle<JSObject> exec_state,
551                            Handle<JSObject> event_data,
552                            bool auto_continue);
553  void InvokeMessageHandler(MessageImpl message);
554
555  void ClearOneShot();
556  void ActivateStepOut(StackFrame* frame);
557  void RemoveDebugInfoAndClearFromShared(Handle<DebugInfo> debug_info);
558  Handle<Object> CheckBreakPoints(Handle<Object> break_point);
559  bool CheckBreakPoint(Handle<Object> break_point_object);
560  MaybeHandle<Object> CallFunction(const char* name, int argc,
561                                   Handle<Object> args[]);
562
563  inline void AssertDebugContext() {
564    DCHECK(isolate_->context() == *debug_context());
565    DCHECK(in_debug_scope());
566  }
567
568  void ThreadInit();
569
570  // Global handles.
571  Handle<Context> debug_context_;
572  Handle<Object> event_listener_;
573  Handle<Object> event_listener_data_;
574
575  v8::Debug::MessageHandler message_handler_;
576
577  static const int kQueueInitialSize = 4;
578  base::Semaphore command_received_;  // Signaled for each command received.
579  LockingCommandMessageQueue command_queue_;
580
581  bool is_active_;
582  bool is_suppressed_;
583  bool live_edit_enabled_;
584  bool break_disabled_;
585  bool break_points_active_;
586  bool in_debug_event_listener_;
587  bool break_on_exception_;
588  bool break_on_uncaught_exception_;
589
590  DebugInfoListNode* debug_info_list_;  // List of active debug info objects.
591
592  // Storage location for jump when exiting debug break calls.
593  // Note that this address is not GC safe.  It should be computed immediately
594  // before returning to the DebugBreakCallHelper.
595  Address after_break_target_;
596
597  // Used to collect histogram data on debugger feature usage.
598  DebugFeatureTracker feature_tracker_;
599
600  // Per-thread data.
601  class ThreadLocal {
602   public:
603    // Top debugger entry.
604    base::AtomicWord current_debug_scope_;
605
606    // Counter for generating next break id.
607    int break_count_;
608
609    // Current break id.
610    int break_id_;
611
612    // Frame id for the frame of the current break.
613    StackFrame::Id break_frame_id_;
614
615    // Step action for last step performed.
616    StepAction last_step_action_;
617
618    // Source statement position from last step next action.
619    int last_statement_position_;
620
621    // Frame pointer from last step next or step frame action.
622    Address last_fp_;
623
624    // Frame pointer of the target frame we want to arrive at.
625    Address target_fp_;
626
627    // Whether functions are flooded on entry for step-in and step-frame.
628    // If we stepped out to the embedder, disable flooding to spill stepping
629    // to the next call that the embedder makes.
630    bool step_in_enabled_;
631
632    // Stores the way how LiveEdit has patched the stack. It is used when
633    // debugger returns control back to user script.
634    LiveEdit::FrameDropMode frame_drop_mode_;
635  };
636
637  // Storage location for registers when handling debug break calls
638  ThreadLocal thread_local_;
639
640  Isolate* isolate_;
641
642  friend class Isolate;
643  friend class DebugScope;
644  friend class DisableBreak;
645  friend class LiveEdit;
646  friend class SuppressDebug;
647
648  friend Handle<FixedArray> GetDebuggedFunctions();  // In test-debug.cc
649  friend void CheckDebuggerUnloaded(bool check_functions);  // In test-debug.cc
650
651  DISALLOW_COPY_AND_ASSIGN(Debug);
652};
653
654
655// This scope is used to load and enter the debug context and create a new
656// break state.  Leaving the scope will restore the previous state.
657// On failure to load, FailedToEnter returns true.
658class DebugScope BASE_EMBEDDED {
659 public:
660  explicit DebugScope(Debug* debug);
661  ~DebugScope();
662
663  // Check whether loading was successful.
664  inline bool failed() { return failed_; }
665
666  // Get the active context from before entering the debugger.
667  inline Handle<Context> GetContext() { return save_.context(); }
668
669 private:
670  Isolate* isolate() { return debug_->isolate_; }
671
672  Debug* debug_;
673  DebugScope* prev_;               // Previous scope if entered recursively.
674  StackFrame::Id break_frame_id_;  // Previous break frame id.
675  int break_id_;                   // Previous break id.
676  bool failed_;                    // Did the debug context fail to load?
677  SaveContext save_;               // Saves previous context.
678  PostponeInterruptsScope no_termination_exceptons_;
679};
680
681
682// Stack allocated class for disabling break.
683class DisableBreak BASE_EMBEDDED {
684 public:
685  explicit DisableBreak(Debug* debug, bool disable_break)
686      : debug_(debug),
687        previous_break_disabled_(debug->break_disabled_),
688        previous_in_debug_event_listener_(debug->in_debug_event_listener_) {
689    debug_->break_disabled_ = disable_break;
690    debug_->in_debug_event_listener_ = disable_break;
691  }
692  ~DisableBreak() {
693    debug_->break_disabled_ = previous_break_disabled_;
694    debug_->in_debug_event_listener_ = previous_in_debug_event_listener_;
695  }
696
697 private:
698  Debug* debug_;
699  bool previous_break_disabled_;
700  bool previous_in_debug_event_listener_;
701  DISALLOW_COPY_AND_ASSIGN(DisableBreak);
702};
703
704
705class SuppressDebug BASE_EMBEDDED {
706 public:
707  explicit SuppressDebug(Debug* debug)
708      : debug_(debug), old_state_(debug->is_suppressed_) {
709    debug_->is_suppressed_ = true;
710  }
711  ~SuppressDebug() { debug_->is_suppressed_ = old_state_; }
712
713 private:
714  Debug* debug_;
715  bool old_state_;
716  DISALLOW_COPY_AND_ASSIGN(SuppressDebug);
717};
718
719
720// Code generator routines.
721class DebugCodegen : public AllStatic {
722 public:
723  enum DebugBreakCallHelperMode {
724    SAVE_RESULT_REGISTER,
725    IGNORE_RESULT_REGISTER
726  };
727
728  static void GenerateDebugBreakStub(MacroAssembler* masm,
729                                     DebugBreakCallHelperMode mode);
730
731  // FrameDropper is a code replacement for a JavaScript frame with possibly
732  // several frames above.
733  // There is no calling conventions here, because it never actually gets
734  // called, it only gets returned to.
735  static void GenerateFrameDropperLiveEdit(MacroAssembler* masm);
736
737
738  static void GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode);
739
740  static void PatchDebugBreakSlot(Isolate* isolate, Address pc,
741                                  Handle<Code> code);
742  static void ClearDebugBreakSlot(Isolate* isolate, Address pc);
743};
744
745
746}  // namespace internal
747}  // namespace v8
748
749#endif  // V8_DEBUG_DEBUG_H_
750