Refactor the convertion of a target address into a code object from the debug...

src/ic-inl.h

 // 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 41 matching lines @@
     // the running code.
     return OriginalCodeAddress();
   } else {
     // No break point here just return the address of the call.
     return result;
   }
 }
 
 
 Code* IC::GetTargetAtAddress(Address address) {
+  // Get the target address of the IC.
   Address target = Assembler::target_address_at(address);
-  HeapObject* code = HeapObject::FromAddress(target - Code::kHeaderSize);
-  // GetTargetAtAddress is called from IC::Clear which in turn is
-  // called when marking objects during mark sweep. reinterpret_cast
-  // is therefore used instead of the more appropriate
-  // Code::cast. Code::cast does not work when the object's map is
-  // marked.
-  Code* result = reinterpret_cast<Code*>(code);
+  // Convert target address to the code object. Code::GetCodeFromTargetAddress
+  // is safe for use during GC where the map might be marked.
+  Code* result = Code::GetCodeFromTargetAddress(target);
   ASSERT(result->is_inline_cache_stub());
   return result;
 }
 
 
 void IC::SetTargetAtAddress(Address address, Code* target) {
   ASSERT(target->is_inline_cache_stub());
   Assembler::set_target_address_at(address, target->instruction_start());
 }
 
 
 Map* IC::GetCodeCacheMapForObject(Object* object) {
   if (object->IsJSObject()) return JSObject::cast(object)->map();
   // If the object is a value, we use the prototype map for the cache.
   ASSERT(object->IsString() || object->IsNumber() || object->IsBoolean());
   return JSObject::cast(object->GetPrototype())->map();
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_INL_H_