Debug: support breakpoints set in the middle of statement

src/debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 217 matching lines @@
     Next();
   }
 
   // Move to the break point found.
   Reset();
   Next(closest_break_point);
 }
 
 
 // Find the break point closest to the supplied source position.
-void BreakLocationIterator::FindBreakLocationFromPosition(int position) {
+void BreakLocationIterator::FindBreakLocationFromPosition(int position,
+    BreakPositionAlignment alignment) {
   // Run through all break points to locate the one closest to the source
   // position.
   int closest_break_point = 0;
   int distance = kMaxInt;
+
   while (!Done()) {
+    int next_position;
+    switch (alignment) {
+    case STATEMENT_ALIGNED:
+      next_position = this->statement_position();
+      break;
+    case BREAK_POSITION_ALIGNED:
+      next_position = this->position();
+      break;
+    default:
+      UNREACHABLE();
+      next_position = this->statement_position();
+    }
     // Check if this break point is closer that what was previously found.
-    if (position <= statement_position() &&
-        statement_position() - position < distance) {
+    if (position <= next_position && next_position - position < distance) {
       closest_break_point = break_point();
-      distance = statement_position() - position;
+      distance = next_position - position;
       // Check whether we can't get any closer.
       if (distance == 0) break;
     }
     Next();
   }
 
   // Move to the break point found.
   Reset();
   Next(closest_break_point);
 }
@@ skipping 924 matching lines @@
     // Return if retrieving debug info failed.
     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.FindBreakLocationFromPosition(*source_position, STATEMENT_ALIGNED);
   it.SetBreakPoint(break_point_object);
 
   *source_position = it.position();
 
   // At least one active break point now.
   ASSERT(debug_info->GetBreakPointCount() > 0);
 }
 
 
 bool Debug::SetBreakPointForScript(Handle<Script> script,
                                    Handle<Object> break_point_object,
-                                   int* source_position) {
+                                   int* source_position,
+                                   BreakPositionAlignment alignment) {
   HandleScope scope(isolate_);
 
   PrepareForBreakPoints();
 
   // Obtain shared function info for the function.
   Object* result = FindSharedFunctionInfoInScript(script, *source_position);
   if (result->IsUndefined()) return false;
 
   // Make sure the function has set up the debug info.
   Handle<SharedFunctionInfo> shared(SharedFunctionInfo::cast(result));
@@ skipping 10 matching lines @@
   } else {
     position = *source_position - shared->start_position();
   }
 
   Handle<DebugInfo> debug_info = GetDebugInfo(shared);
   // Source positions starts with zero.
   ASSERT(position >= 0);
 
   // Find the break point and change it.
   BreakLocationIterator it(debug_info, SOURCE_BREAK_LOCATIONS);
-  it.FindBreakLocationFromPosition(position);
+  it.FindBreakLocationFromPosition(position, alignment);
   it.SetBreakPoint(break_point_object);
 
   *source_position = it.position() + shared->start_position();
 
   // At least one active break point now.
   ASSERT(debug_info->GetBreakPointCount() > 0);
   return true;
 }
 
 
@@ skipping 433 matching lines @@
     }
   }
 
   UNREACHABLE();
   return Handle<Code>::null();
 }
 
 
 // Simple function for returning the source positions for active break points.
 Handle<Object> Debug::GetSourceBreakLocations(
-    Handle<SharedFunctionInfo> shared) {
+    Handle<SharedFunctionInfo> shared,
+    BreakPositionAlignment position_alignment) {
   Isolate* isolate = Isolate::Current();
   Heap* heap = isolate->heap();
   if (!HasDebugInfo(shared)) {
     return Handle<Object>(heap->undefined_value(), isolate);
   }
   Handle<DebugInfo> debug_info = GetDebugInfo(shared);
   if (debug_info->GetBreakPointCount() == 0) {
     return Handle<Object>(heap->undefined_value(), isolate);
   }
   Handle<FixedArray> locations =
       isolate->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());
+        Smi* position;
+        switch (position_alignment) {
+        case STATEMENT_ALIGNED:
+          position = break_point_info->statement_position();
+          break;
+        case BREAK_POSITION_ALIGNED:
+          position = break_point_info->source_position();
+          break;
+        default:
+          UNREACHABLE();
+          position = break_point_info->statement_position();
+        }
+
+        locations->set(count++, position);
       }
     }
   }
   return locations;
 }
 
 
 void Debug::NewBreak(StackFrame::Id break_frame_id) {
   thread_local_.break_frame_id_ = break_frame_id;
   thread_local_.break_id_ = ++thread_local_.break_count_;
@@ skipping 2095 matching lines @@
     {
       Locker locker(reinterpret_cast<v8::Isolate*>(isolate_));
       isolate_->debugger()->CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal