Introduce Runtime_GetAllScopesDetails to get all scopes at once for a frame.

This will reduce heavy ScopeIterator instantiations.
Once incorporated into chromium, will give 30% speed boost.

BUG=chromium:340285
LOG=Y
R=ulan@chromium.org, Yang, rossberg, ulan

Review URL: https://codereview.chromium.org/181063008

Patch from Andrey Adaykin <aandrey@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19717 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mirror-debugger.js

@@ -1687,6 +1687,18 @@ FrameMirror.prototype.scope = function(index) {
 };
 
 
+FrameMirror.prototype.allScopes = function() {
+  var scopeDetails = %GetAllScopesDetails(this.break_id_,
+                                          this.details_.frameId(),
+                                          this.details_.inlinedFrameIndex());
+  var result = [];
+  for (var i = 0; i < scopeDetails.length; ++i) {
+    result.push(new ScopeMirror(this, UNDEFINED, i, scopeDetails[i]));
+  }
+  return result;
+};
+
+
 FrameMirror.prototype.stepInPositions = function() {
   var script = this.func().script();
   var funcOffset = this.func().sourcePosition_();
@@ -1878,17 +1890,18 @@ FrameMirror.prototype.toText = function(opt_locals) {
 var kScopeDetailsTypeIndex = 0;
 var kScopeDetailsObjectIndex = 1;
 
-function ScopeDetails(frame, fun, index) {
+function ScopeDetails(frame, fun, index, opt_details) {
   if (frame) {
     this.break_id_ = frame.break_id_;
-    this.details_ = %GetScopeDetails(frame.break_id_,
+    this.details_ = opt_details ||
+                    %GetScopeDetails(frame.break_id_,
                                      frame.details_.frameId(),
                                      frame.details_.inlinedFrameIndex(),
                                      index);
     this.frame_id_ = frame.details_.frameId();
     this.inlined_frame_id_ = frame.details_.inlinedFrameIndex();
   } else {
-    this.details_ = %GetFunctionScopeDetails(fun.value(), index);
+    this.details_ = opt_details || %GetFunctionScopeDetails(fun.value(), index);
     this.fun_value_ = fun.value();
     this.break_id_ = undefined;
   }
@@ -1934,10 +1947,11 @@ ScopeDetails.prototype.setVariableValueImpl = function(name, new_value) {
  * @param {FrameMirror} frame The frame this scope is a part of
  * @param {FunctionMirror} function The function this scope is a part of
  * @param {number} index The scope index in the frame
+ * @param {Array=} opt_details Raw scope details data
  * @constructor
  * @extends Mirror
  */
-function ScopeMirror(frame, function, index) {
+function ScopeMirror(frame, function, index, opt_details) {
   %_CallFunction(this, SCOPE_TYPE, Mirror);
   if (frame) {
     this.frame_index_ = frame.index_;
@@ -1945,7 +1959,7 @@ function ScopeMirror(frame, function, index) {
     this.frame_index_ = undefined;
   }
   this.scope_index_ = index;
-  this.details_ = new ScopeDetails(frame, function, index);
+  this.details_ = new ScopeDetails(frame, function, index, opt_details);
 }
 inherits(ScopeMirror, Mirror);
 

src/runtime.cc

@@ -12177,7 +12177,7 @@ static const int kScopeDetailsObjectIndex = 1;
 static const int kScopeDetailsSize = 2;
 
 
-static MaybeObject* MaterializeScopeDetails(Isolate* isolate,
+static Handle<JSObject> MaterializeScopeDetails(Isolate* isolate,
     ScopeIterator* it) {
   // Calculate the size of the result.
   int details_size = kScopeDetailsSize;
@@ -12186,10 +12186,10 @@ static MaybeObject* MaterializeScopeDetails(Isolate* isolate,
   // Fill in scope details.
   details->set(kScopeDetailsTypeIndex, Smi::FromInt(it->Type()));
   Handle<JSObject> scope_object = it->ScopeObject();
-  RETURN_IF_EMPTY_HANDLE(isolate, scope_object);
+  RETURN_IF_EMPTY_HANDLE_VALUE(isolate, scope_object, Handle<JSObject>());
   details->set(kScopeDetailsObjectIndex, *scope_object);
 
-  return *isolate->factory()->NewJSArrayWithElements(details);
+  return isolate->factory()->NewJSArrayWithElements(details);
 }
 
 
@@ -12230,7 +12230,51 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetScopeDetails) {
   if (it.Done()) {
     return isolate->heap()->undefined_value();
   }
-  return MaterializeScopeDetails(isolate, &it);
+  Handle<JSObject> details = MaterializeScopeDetails(isolate, &it);
+  RETURN_IF_EMPTY_HANDLE(isolate, details);
+  return *details;
+}
+
+
+// Return an array of scope details
+// args[0]: number: break id
+// args[1]: number: frame index
+// args[2]: number: inlined frame index
+//
+// The array returned contains arrays with the following information:
+// 0: Scope type
+// 1: Scope object
+RUNTIME_FUNCTION(MaybeObject*, Runtime_GetAllScopesDetails) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 3);
+
+  // 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);
+  CONVERT_NUMBER_CHECKED(int, inlined_jsframe_index, Int32, args[2]);
+
+  // Get the frame where the debugging is performed.
+  StackFrame::Id id = UnwrapFrameId(wrapped_id);
+  JavaScriptFrameIterator frame_it(isolate, id);
+  JavaScriptFrame* frame = frame_it.frame();
+
+  List<Handle<JSObject> > result(4);
+  ScopeIterator it(isolate, frame, inlined_jsframe_index);
+  for (; !it.Done(); it.Next()) {
+    Handle<JSObject> details = MaterializeScopeDetails(isolate, &it);
+    RETURN_IF_EMPTY_HANDLE(isolate, details);
+    result.Add(details);
+  }
+
+  Handle<FixedArray> array = isolate->factory()->NewFixedArray(result.length());
+  for (int i = 0; i < result.length(); ++i) {
+    array->set(i, *result[i]);
+  }
+  return *isolate->factory()->NewJSArrayWithElements(array);
 }
 
 
@@ -12269,7 +12313,9 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFunctionScopeDetails) {
     return isolate->heap()->undefined_value();
   }
 
-  return MaterializeScopeDetails(isolate, &it);
+  Handle<JSObject> details = MaterializeScopeDetails(isolate, &it);
+  RETURN_IF_EMPTY_HANDLE(isolate, details);
+  return *details;
 }
 
 

src/runtime.h

@@ -492,6 +492,7 @@ namespace internal {
   F(GetScopeCount, 2, 1) \
   F(GetStepInPositions, 2, 1) \
   F(GetScopeDetails, 4, 1) \
+  F(GetAllScopesDetails, 3, 1) \
   F(GetFunctionScopeCount, 1, 1) \
   F(GetFunctionScopeDetails, 2, 1) \
   F(SetScopeVariableValue, 6, 1) \

test/mjsunit/debug-scopes.js

@@ -76,13 +76,24 @@ function EndTest() {
 }
 
 
+// Check that two scope are the same.
+function CheckScopeMirrors(scope1, scope2) {
+  assertEquals(scope1.scopeType(), scope2.scopeType());
+  assertEquals(scope1.frameIndex(), scope2.frameIndex());
+  assertEquals(scope1.scopeIndex(), scope2.scopeIndex());
+}
+
+
 // Check that the scope chain contains the expected types of scopes.
 function CheckScopeChain(scopes, exec_state) {
+  var all_scopes = exec_state.frame().allScopes();
   assertEquals(scopes.length, exec_state.frame().scopeCount());
+  assertEquals(scopes.length, all_scopes.length, "FrameMirror.allScopes length");
   for (var i = 0; i < scopes.length; i++) {
     var scope = exec_state.frame().scope(i);
     assertTrue(scope.isScope());
     assertEquals(scopes[i], scope.scopeType());
+    CheckScopeMirrors(all_scopes[i], scope);
 
     // Check the global object when hitting the global scope.
     if (scopes[i] == debug.ScopeType.Global) {