[debugger] remove frame argument for prepare step.

The third argument optionally specifies the frame from which to step.
This feature is not used and not well tested.

R=jkummerow@chromium.org
BUG=chromium:569835
LOG=N

Review URL: https://codereview.chromium.org/1525993002

Cr-Commit-Position: refs/heads/master@{#32865}

src/debug/debug.cc

@@ -493,7 +493,7 @@ void Debug::Break(Arguments args, JavaScriptFrame* frame) {
       // Clear queue
       thread_local_.queued_step_count_ = 0;
 
-      PrepareStep(StepNext, step_count, StackFrame::NO_ID);
+      PrepareStep(StepNext, step_count);
     } else {
       // Notify the debug event listeners.
       OnDebugBreak(break_points_hit, false);
@@ -531,7 +531,7 @@ void Debug::Break(Arguments args, JavaScriptFrame* frame) {
     ClearStepping();
 
     // Set up for the remaining steps.
-    PrepareStep(step_action, step_count, StackFrame::NO_ID);
+    PrepareStep(step_action, step_count);
   }
 }
 
@@ -833,9 +833,7 @@ void Debug::PrepareStepOnThrow() {
 }
 
 
-void Debug::PrepareStep(StepAction step_action,
-                        int step_count,
-                        StackFrame::Id frame_id) {
+void Debug::PrepareStep(StepAction step_action, int step_count) {
   HandleScope scope(isolate_);
 
   DCHECK(in_debug_scope());
@@ -844,15 +842,11 @@ void Debug::PrepareStep(StepAction step_action,
   // 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 = break_frame_id();
-  if (id == StackFrame::NO_ID) {
+  StackFrame::Id frame_id = break_frame_id();
   // If there is no JavaScript stack don't do anything.
-    return;
-  }
-  if (frame_id != StackFrame::NO_ID) {
-    id = frame_id;
-  }
-  JavaScriptFrameIterator frames_it(isolate_, id);
+  if (frame_id == StackFrame::NO_ID) return;
+
+  JavaScriptFrameIterator frames_it(isolate_, frame_id);
   JavaScriptFrame* frame = frames_it.frame();
 
   feature_tracker()->Track(DebugFeatureTracker::kStepping);

src/debug/debug.h

@@ -408,9 +408,7 @@ class Debug {
   bool IsBreakOnException(ExceptionBreakType type);
 
   // Stepping handling.
-  void PrepareStep(StepAction step_action,
-                   int step_count,
-                   StackFrame::Id frame_id);
+  void PrepareStep(StepAction step_action, int step_count);
   void PrepareStepIn(Handle<JSFunction> function);
   void PrepareStepOnThrow();
   void ClearStepping();

src/debug/debug.js

@@ -943,17 +943,11 @@ function ExecutionState(break_id) {
   this.selected_frame = 0;
 }
 
-ExecutionState.prototype.prepareStep = function(opt_action, opt_count,
-    opt_callframe) {
+ExecutionState.prototype.prepareStep = function(opt_action, opt_count) {
   var action = Debug.StepAction.StepIn;
   if (!IS_UNDEFINED(opt_action)) action = TO_NUMBER(opt_action);
   var count = opt_count ? TO_NUMBER(opt_count) : 1;
-  var callFrameId = 0;
-  if (!IS_UNDEFINED(opt_callframe)) {
-    callFrameId = opt_callframe.details_.frameId();
-  }
-
-  return %PrepareStep(this.break_id, action, count, callFrameId);
+  return %PrepareStep(this.break_id, action, count);
 };
 
 ExecutionState.prototype.evaluateGlobal = function(source, disable_break,

src/runtime/runtime-debug.cc

@@ -1212,7 +1212,7 @@ RUNTIME_FUNCTION(Runtime_IsBreakOnException) {
 //          of frames to step down.
 RUNTIME_FUNCTION(Runtime_PrepareStep) {
   HandleScope scope(isolate);
-  DCHECK(args.length() == 4);
+  DCHECK(args.length() == 3);
   CONVERT_NUMBER_CHECKED(int, break_id, Int32, args[0]);
   RUNTIME_ASSERT(isolate->debug()->CheckExecutionState(break_id));
 
@@ -1220,15 +1220,6 @@ RUNTIME_FUNCTION(Runtime_PrepareStep) {
     return isolate->Throw(isolate->heap()->illegal_argument_string());
   }
 
-  CONVERT_NUMBER_CHECKED(int, wrapped_frame_id, Int32, args[3]);
-
-  StackFrame::Id frame_id;
-  if (wrapped_frame_id == 0) {
-    frame_id = StackFrame::NO_ID;
-  } else {
-    frame_id = DebugFrameHelper::UnwrapFrameId(wrapped_frame_id);
-  }
-
   // Get the step action and check validity.
   StepAction step_action = static_cast<StepAction>(NumberToInt32(args[1]));
   if (step_action != StepIn && step_action != StepNext &&
@@ -1236,11 +1227,6 @@ RUNTIME_FUNCTION(Runtime_PrepareStep) {
     return isolate->Throw(isolate->heap()->illegal_argument_string());
   }
 
-  if (frame_id != StackFrame::NO_ID && step_action != StepNext &&
-      step_action != StepOut) {
-    return isolate->ThrowIllegalOperation();
-  }
-
   // Get the number of steps.
   int step_count = NumberToInt32(args[2]);
   if (step_count < 1) {
@@ -1252,7 +1238,7 @@ RUNTIME_FUNCTION(Runtime_PrepareStep) {
 
   // Prepare step.
   isolate->debug()->PrepareStep(static_cast<StepAction>(step_action),
-                                step_count, frame_id);
+                                step_count);
   return isolate->heap()->undefined_value();
 }
 

src/runtime/runtime.h

@@ -183,7 +183,7 @@ namespace internal {
   F(ClearBreakPoint, 1, 1)                     \
   F(ChangeBreakOnException, 2, 1)              \
   F(IsBreakOnException, 1, 1)                  \
-  F(PrepareStep, 4, 1)                         \
+  F(PrepareStep, 3, 1)                         \
   F(ClearStepping, 0, 1)                       \
   F(DebugEvaluate, 6, 1)                       \
   F(DebugEvaluateGlobal, 4, 1)                 \

test/cctest/test-debug.cc

@@ -341,7 +341,7 @@ static void ChangeBreakOnExceptionFromJS(v8::Isolate* isolate, bool caught,
 // Prepare to step to next break location.
 static void PrepareStep(StepAction step_action) {
   v8::internal::Debug* debug = CcTest::i_isolate()->debug();
-  debug->PrepareStep(step_action, 1, StackFrame::NO_ID);
+  debug->PrepareStep(step_action, 1);
 }
 
 

test/mjsunit/debug-step-4-in-frame.js → test/mjsunit/debug-step-4.js

@@ -53,8 +53,8 @@ function h() {
   }
 }
 
-function TestCase(frame_index, step_count, expected_final_state) {
-  print("Test case, parameters " + frame_index + "/" + step_count);
+function TestCase(step_count, expected_final_state) {
+  print("Test case, step count: " + step_count);
 
   var listener_exception = null;
   var state_snapshot;
@@ -68,12 +68,7 @@ function TestCase(frame_index, step_count, expected_final_state) {
       if (event == Debug.DebugEvent.Break) {
         if (listener_state == 0) {
           Debug.clearBreakPoint(bp);
-          var context_frame;
-          if (frame_index !== undefined) {
-            context_frame = exec_state.frame(frame_index);
-          }
-          exec_state.prepareStep(Debug.StepAction.StepNext,
-              step_count, context_frame);
+          exec_state.prepareStep(Debug.StepAction.StepNext, step_count);
           listener_state = 1;
         } else if (listener_state == 1) {
           state_snapshot = String(state);
@@ -107,26 +102,8 @@ function TestCase(frame_index, step_count, expected_final_state) {
 // Warm-up -- make sure all is compiled and ready for breakpoint.
 h();
 
-
-// Stepping in the default (top) frame.
-TestCase(undefined, 0, "0,0,-1");
-TestCase(undefined, 1, "0,0,-1");
-TestCase(undefined, 2, "0,0,0");
-TestCase(undefined, 5, "0,0,1");
-TestCase(undefined, 8, "0,0,3");
-
-// Stepping in the frame #0 (should be exactly the same as above).
-TestCase(0, 0, "0,0,-1");
-TestCase(0, 1, "0,0,-1");
-TestCase(0, 2, "0,0,0");
-TestCase(0, 5, "0,0,1");
-TestCase(0, 8, "0,0,3");
-
-// Stepping in the frame #1.
-TestCase(1, 0, "0,0,3");
-TestCase(1, 3, "0,1,3");
-TestCase(1, 7, "0,3,3");
-
-// Stepping in the frame #2.
-TestCase(2, 3, "1,3,3");
-TestCase(2, 7, "3,3,3");
+TestCase(0, "0,0,-1");
+TestCase(1, "0,0,-1");
+TestCase(2, "0,0,0");
+TestCase(5, "0,0,1");
+TestCase(8, "0,0,2");

test/mjsunit/mjsunit.status

@@ -30,11 +30,6 @@
   # All tests in the bug directory are expected to fail.
   'bugs/*': [FAIL],
 
-  ##############################################################################
-  # Flaky tests.
-  # BUG(v8:2921).
-  'debug-step-4-in-frame': [PASS, FAIL, SLOW],
-
   ##############################################################################
   # Fails.
   'regress/regress-1119': [FAIL],