Revert of Revert of [strong] Implement strong mode restrictions on property access

src/ic/ic-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_IC_INL_H_
 #define V8_IC_INL_H_
 
 #include "src/ic/ic.h"
 
 #include "src/compiler.h"
@@ skipping 117 matching lines @@
 void IC::set_target(Code* code) {
   SetTargetAtAddress(address(), code, constant_pool());
   target_set_ = true;
 }
 
 
 void LoadIC::set_target(Code* code) {
   // The contextual mode must be preserved across IC patching.
   DCHECK(LoadICState::GetContextualMode(code->extra_ic_state()) ==
          LoadICState::GetContextualMode(target()->extra_ic_state()));
+  // Strongness must be preserved across IC patching.
+  DCHECK(LoadICState::GetLanguageMode(code->extra_ic_state()) ==
+         LoadICState::GetLanguageMode(target()->extra_ic_state()));
 
   IC::set_target(code);
 }
 
 
 void StoreIC::set_target(Code* code) {
   // Language mode must be preserved across IC patching.
   DCHECK(StoreICState::GetLanguageMode(code->extra_ic_state()) ==
          StoreICState::GetLanguageMode(target()->extra_ic_state()));
   IC::set_target(code);
@@ skipping 81 matching lines @@
 bool IC::AddressIsDeoptimizedCode(Isolate* isolate, Address address) {
   Code* host =
       isolate->inner_pointer_to_code_cache()->GetCacheEntry(address)->code;
   return (host->kind() == Code::OPTIMIZED_FUNCTION &&
           host->marked_for_deoptimization());
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_IC_INL_H_