debug.cc.svn-base

Google浏览器V8内核代码

    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) {
  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::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() {
  StackFrame::Id id = Top::break_frame_id();
  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 = Top::break_frame_id();
  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 = Debug::GetCodeTarget(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 = GetCodeTarget(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 = Debug::GetCodeTarget(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::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);
}


// 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 {