Debugger: fix stepping when break points are deactivated.

The flag for deactivating break points also affects stepping, since both
are implemented via debug break slots. Fixing this by introducing a new
flag solely responsible for deactivating actual break points.

R=mvstanton@chromium.org
BUG=chromium:119800
LOG=N

Review URL: https://codereview.chromium.org/1402913002

Cr-Commit-Position: refs/heads/master@{#31236}

src/debug/debug.cc

@@ -38,6 +38,7 @@ Debug::Debug(Isolate* isolate)
       is_suppressed_(false),
       live_edit_enabled_(true),  // TODO(yangguo): set to false by default.
       break_disabled_(false),
+      break_points_active_(true),
       in_debug_event_listener_(false),
       break_on_exception_(false),
       break_on_uncaught_exception_(false),
@@ -457,7 +458,7 @@ void Debug::Break(Arguments args, JavaScriptFrame* frame) {
   // If there is one or more real break points check whether any of these are
   // triggered.
   Handle<Object> break_points_hit(heap->undefined_value(), isolate_);
-  if (break_location.HasBreakPoint()) {
+  if (break_points_active_ && break_location.HasBreakPoint()) {
     Handle<Object> break_point_objects = break_location.BreakPointObjects();
     break_points_hit = CheckBreakPoints(break_point_objects);
   }

src/debug/debug.h

@@ -482,7 +482,7 @@ class Debug {
   inline bool in_debug_scope() const {
     return !!base::NoBarrier_Load(&thread_local_.current_debug_scope_);
   }
-  void set_disable_break(bool v) { break_disabled_ = v; }
+  void set_break_points_active(bool v) { break_points_active_ = v; }
 
   StackFrame::Id break_frame_id() { return thread_local_.break_frame_id_; }
   int break_id() { return thread_local_.break_id_; }
@@ -593,6 +593,7 @@ class Debug {
   bool is_suppressed_;
   bool live_edit_enabled_;
   bool break_disabled_;
+  bool break_points_active_;
   bool in_debug_event_listener_;
   bool break_on_exception_;
   bool break_on_uncaught_exception_;

src/debug/debug.js

@@ -100,7 +100,7 @@ var debugger_flags = {
     getValue: function() { return this.value; },
     setValue: function(value) {
       this.value = !!value;
-      %SetDisableBreak(!this.value);
+      %SetBreakPointsActive(this.value);
     }
   },
   breakOnCaughtException: {

src/runtime/runtime-debug.cc

@@ -1062,11 +1062,11 @@ RUNTIME_FUNCTION(Runtime_GetThreadDetails) {
 
 // Sets the disable break state
 // args[0]: disable break state
-RUNTIME_FUNCTION(Runtime_SetDisableBreak) {
+RUNTIME_FUNCTION(Runtime_SetBreakPointsActive) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
-  CONVERT_BOOLEAN_ARG_CHECKED(disable_break, 0);
-  isolate->debug()->set_disable_break(disable_break);
+  CONVERT_BOOLEAN_ARG_CHECKED(active, 0);
+  isolate->debug()->set_break_points_active(active);
   return isolate->heap()->undefined_value();
 }
 

src/runtime/runtime.h

@@ -176,7 +176,7 @@ namespace internal {
   F(DebugPrintScopes, 0, 1)                    \
   F(GetThreadCount, 1, 1)                      \
   F(GetThreadDetails, 2, 1)                    \
-  F(SetDisableBreak, 1, 1)                     \
+  F(SetBreakPointsActive, 1, 1)                \
   F(GetBreakLocations, 2, 1)                   \
   F(SetFunctionBreakPoint, 3, 1)               \
   F(SetScriptBreakPoint, 4, 1)                 \

test/mjsunit/regress/regress-crbug-119800.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --expose-debug-as debug
+
+function f() {
+  1;
+  2;
+  3;
+}
+
+var Debug = debug.Debug;
+var exception = null;
+var breaks = [];
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    Debug.debuggerFlags().breakPointsActive.setValue(false);
+    breaks.push(exec_state.frame().sourceLineText().trimLeft());
+    exec_state.prepareStep(Debug.StepAction.StepIn, 1);
+  } catch (e) {
+    exception = e;
+  }
+}
+
+Debug.setListener(listener);
+Debug.setBreakPoint(f, 0, 0);
+
+f();
+
+Debug.setListener(null);
+Debug.debuggerFlags().breakPointsActive.setValue(true);
+
+assertNull(exception);
+assertEquals(breaks, ["1;", "2;", "3;", "}", "Debug.setListener(null);"]);