Add asserts to ensure that we:

src/builtins.cc

 // Copyright 2011 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 1603 matching lines @@
   // separate code object for each one.
   for (int i = 0; i < builtin_count; i++) {
     if (create_heap_objects) {
       MacroAssembler masm(isolate, buffer, sizeof buffer);
       // Generate the code/adaptor.
       typedef void (*Generator)(MacroAssembler*, int, BuiltinExtraArguments);
       Generator g = FUNCTION_CAST<Generator>(functions[i].generator);
       // We pass all arguments to the generator, but it may not use all of
       // them.  This works because the first arguments are on top of the
       // stack.
+      ASSERT(!masm.has_frame());
       g(&masm, functions[i].name, functions[i].extra_args);
       // Move the code into the object heap.
       CodeDesc desc;
       masm.GetCode(&desc);
       Code::Flags flags =  functions[i].flags;
       Object* code = NULL;
       {
         // During startup it's OK to always allocate and defer GC to later.
         // This simplifies things because we don't need to retry.
         AlwaysAllocateScope __scope__;
@@ skipping 69 matching lines @@
   return Handle<Code>(code_address);                        \
 }
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 } }  // namespace v8::internal