Fix assertion when collecting stack trace from debug break.

src/frames.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 972 matching lines @@
   int i = jsframe_count;
   while (i > 0) {
     opcode = static_cast<Translation::Opcode>(it.Next());
     if (opcode == Translation::JS_FRAME) {
       i--;
       BailoutId ast_id = BailoutId(it.Next());
       JSFunction* function = LiteralAt(literal_array, it.Next());
       it.Next();  // Skip height.
 
       // The translation commands are ordered and the receiver is always
-      // at the first position. Since we are always at a call when we need
-      // to construct a stack trace, the receiver is always in a stack slot.
+      // at the first position.
+      // If we are at a call, the receiver is always in a stack slot.
+      // Otherwise we are not guaranteed to get the receiver value.
       opcode = static_cast<Translation::Opcode>(it.Next());
-      ASSERT(opcode == Translation::STACK_SLOT ||
-             opcode == Translation::LITERAL ||
-             opcode == Translation::CAPTURED_OBJECT ||
-             opcode == Translation::DUPLICATED_OBJECT);
       int index = it.Next();
 
       // Get the correct receiver in the optimized frame.
       Object* receiver = NULL;
       if (opcode == Translation::LITERAL) {
         receiver = data->LiteralArray()->get(index);
       } else if (opcode == Translation::STACK_SLOT) {
         // Positive index means the value is spilled to the locals
         // area. Negative means it is stored in the incoming parameter
         // area.
         if (index >= 0) {
           receiver = GetExpression(index);
         } else {
           // Index -1 overlaps with last parameter, -n with the first parameter,
           // (-n - 1) with the receiver with n being the number of parameters
           // of the outermost, optimized frame.
           int parameter_count = ComputeParametersCount();
           int parameter_index = index + parameter_count;
           receiver = (parameter_index == -1)
               ? this->receiver()
               : this->GetParameter(parameter_index);
         }
       } else {
+        // The receiver is not in a stack slot nor in a literal.  We give up.
         // TODO(3029): Materializing a captured object (or duplicated
         // object) is hard, we return undefined for now. This breaks the
         // produced stack trace, as constructor frames aren't marked as
         // such anymore.
         receiver = isolate()->heap()->undefined_value();
       }
 
       Code* code = function->shared()->code();
       DeoptimizationOutputData* output_data =
           DeoptimizationOutputData::cast(code->deoptimization_data());
@@ skipping 608 matching lines @@
   ZoneList<StackFrame*> list(10, zone);
   for (StackFrameIterator it(isolate); !it.done(); it.Advance()) {
     StackFrame* frame = AllocateFrameCopy(it.frame(), zone);
     list.Add(frame, zone);
   }
   return list.ToVector();
 }
 
 
 } }  // namespace v8::internal