Reverting 3174. Aka reapplying 3150, 3151 and 3159. Aka api accessor

src/frames.cc

 // Copyright 2006-2008 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 375 matching lines @@
   Address fp = Memory::Address_at(this->fp() + offset);
   return ExitFrame::GetStateForFramePointer(fp, state);
 }
 
 
 Code* EntryConstructFrame::code() const {
   return Heap::js_construct_entry_code();
 }
 
 
+Object*& ExitFrame::code_slot() const {
+  const int offset = ExitFrameConstants::kCodeOffset;
+  return Memory::Object_at(fp() + offset);
+}
+
+
 Code* ExitFrame::code() const {
-  return Heap::c_entry_code();
+  Object* code = code_slot();
+  if (code->IsSmi()) {
+    return Heap::c_entry_debug_break_code();
+  } else {
+    return Code::cast(code);
+  }
 }
 
 
 void ExitFrame::ComputeCallerState(State* state) const {
   // Setup the caller state.
   state->sp = caller_sp();
   state->fp = Memory::Address_at(fp() + ExitFrameConstants::kCallerFPOffset);
   state->pc_address
       = reinterpret_cast<Address*>(fp() + ExitFrameConstants::kCallerPCOffset);
 }
 
 
 Address ExitFrame::GetCallerStackPointer() const {
   return fp() + ExitFrameConstants::kCallerSPDisplacement;
 }
 
 
-Code* ExitDebugFrame::code() const {
-  return Heap::c_entry_debug_break_code();
-}
-
-
 Address StandardFrame::GetExpressionAddress(int n) const {
   const int offset = StandardFrameConstants::kExpressionsOffset;
   return fp() + offset - n * kPointerSize;
 }
 
 
 int StandardFrame::ComputeExpressionsCount() const {
   const int offset =
       StandardFrameConstants::kExpressionsOffset + kPointerSize;
   Address base = fp() + offset;
@@ skipping 304 matching lines @@
         reg_code[i++] = r;
 
     ASSERT(i == kNumJSCallerSaved);
   }
   ASSERT(0 <= n && n < kNumJSCallerSaved);
   return reg_code[n];
 }
 
 
 } }  // namespace v8::internal