Provide list of step-in source positions in JS Debug API

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/15960016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15322 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/debug.cc

@@ -390,6 +390,20 @@ void BreakLocationIterator::ClearDebugBreak() {
 }
 
 
+bool BreakLocationIterator::IsStepInLocation(Isolate* isolate) {
+  if (RelocInfo::IsConstructCall(rmode())) {
+    return true;
+  } else if (RelocInfo::IsCodeTarget(rmode())) {
+    HandleScope scope(debug_info_->GetIsolate());
+    Address target = rinfo()->target_address();
+    Handle<Code> target_code(Code::GetCodeFromTargetAddress(target));
+    return target_code->is_call_stub() || target_code->is_keyed_call_stub();
+  } else {
+    return false;
+  }
+}
+
+
 void BreakLocationIterator::PrepareStepIn(Isolate* isolate) {
   HandleScope scope(isolate);
 

src/debug.h

@@ -97,6 +97,7 @@ class BreakLocationIterator {
   void ClearBreakPoint(Handle<Object> break_point_object);
   void SetOneShot();
   void ClearOneShot();
+  bool IsStepInLocation(Isolate* isolate);
   void PrepareStepIn(Isolate* isolate);
   bool IsExit() const;
   bool HasBreakPoint();

src/mirror-debugger.js

@@ -1509,6 +1509,11 @@ FrameDetails.prototype.scopeCount = function() {
 };
 
 
+FrameDetails.prototype.stepInPositionsImpl = function() {
+  return %GetStepInPositions(this.break_id_, this.frameId());
+};
+
+
 /**
  * Mirror object for stack frames.
  * @param {number} break_id The break id in the VM for which this frame is
@@ -1669,6 +1674,29 @@ FrameMirror.prototype.scope = function(index) {
 };
 
 
+FrameMirror.prototype.stepInPositions = function() {
+  var script = this.func().script();
+  var funcOffset = this.func().sourcePosition_();
+
+  var stepInRaw = this.details_.stepInPositionsImpl();
+  var result = [];
+  if (stepInRaw) {
+    for (var i = 0; i < stepInRaw.length; i++) {
+      var posStruct = {};
+      var offset = script.locationFromPosition(funcOffset + stepInRaw[i],
+                                               true);
+      serializeLocationFields(offset, posStruct);
+      var item = {
+        position: posStruct
+      };
+      result.push(item);
+    }
+  }
+
+  return result;
+};
+
+
 FrameMirror.prototype.evaluate = function(source, disable_break,
                                           opt_context_object) {
   var result = %DebugEvaluate(this.break_id_,

src/runtime.cc

@@ -11778,6 +11778,58 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetScopeCount) {
 }
 
 
+// Returns the list of step-in positions (text offset) in a function of the
+// stack frame in a range from the current debug break position to the end
+// of the corresponding statement.
+RUNTIME_FUNCTION(MaybeObject*, Runtime_GetStepInPositions) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 2);
+
+  // Check arguments.
+  Object* check;
+  { MaybeObject* maybe_check = Runtime_CheckExecutionState(
+      RUNTIME_ARGUMENTS(isolate, args));
+    if (!maybe_check->ToObject(&check)) return maybe_check;
+  }
+  CONVERT_SMI_ARG_CHECKED(wrapped_id, 1);
+
+  // Get the frame where the debugging is performed.
+  StackFrame::Id id = UnwrapFrameId(wrapped_id);
+  JavaScriptFrameIterator frame_it(isolate, id);
+  JavaScriptFrame* frame = frame_it.frame();
+
+  Handle<SharedFunctionInfo> shared =
+      Handle<SharedFunctionInfo>(JSFunction::cast(frame->function())->shared());
+  Handle<DebugInfo> debug_info = Debug::GetDebugInfo(shared);
+
+  int len = 0;
+  Handle<JSArray> array(isolate->factory()->NewJSArray(10));
+  // Find the break point where execution has stopped.
+  BreakLocationIterator break_location_iterator(debug_info,
+                                                ALL_BREAK_LOCATIONS);
+
+  break_location_iterator.FindBreakLocationFromAddress(frame->pc());
+  int current_statement_pos = break_location_iterator.statement_position();
+
+  while (!break_location_iterator.Done()) {
+    if (break_location_iterator.IsStepInLocation(isolate)) {
+      Smi* position_value = Smi::FromInt(break_location_iterator.position());
+      JSObject::SetElement(array, len,
+          Handle<Object>(position_value, isolate),
+          NONE, kNonStrictMode);
+      len++;
+    }
+    // Advance iterator.
+    break_location_iterator.Next();
+    if (current_statement_pos !=
+        break_location_iterator.statement_position()) {
+      break;
+    }
+  }
+  return *array;
+}
+
+
 static const int kScopeDetailsTypeIndex = 0;
 static const int kScopeDetailsObjectIndex = 1;
 static const int kScopeDetailsSize = 2;

src/runtime.h

@@ -490,6 +490,7 @@ namespace internal {
   F(GetFrameCount, 1, 1) \
   F(GetFrameDetails, 2, 1) \
   F(GetScopeCount, 2, 1) \
+  F(GetStepInPositions, 2, 1) \
   F(GetScopeDetails, 4, 1) \
   F(GetFunctionScopeCount, 1, 1) \
   F(GetFunctionScopeDetails, 2, 1) \