"Port" (count >= 0) assertion in VirtualFrame::Drop to ia32 and x64.

src/ia32/virtual-frame-ia32.cc

 // Copyright 2009 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 947 matching lines @@
   ASSERT(num_args.is_valid());
   __ Set(num_args.reg(), Immediate(arg_count));
 
   function.Unuse();
   num_args.Unuse();
   return RawCallCodeObject(ic, RelocInfo::CONSTRUCT_CALL);
 }
 
 
 void VirtualFrame::Drop(int count) {
+  ASSERT(count >= 0);
   ASSERT(height() >= count);
   int num_virtual_elements = (element_count() - 1) - stack_pointer_;
 
   // Emit code to lower the stack pointer if necessary.
   if (num_virtual_elements < count) {
     int num_dropped = count - num_virtual_elements;
     stack_pointer_ -= num_dropped;
     __ add(Operand(esp), Immediate(num_dropped * kPointerSize));
   }
 
@@ skipping 97 matching lines @@
   ASSERT(stack_pointer_ == element_count() - 1);
   elements_.Add(FrameElement::MemoryElement());
   stack_pointer_++;
   __ push(immediate);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal