[ic] Encode [Keyed]StoreIC's language mode in slot kind instead of code object's flags.

src/ic/ic.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_H_
 #define V8_IC_H_
 
 #include "src/ic/ic-state.h"
 #include "src/macro-assembler.h"
 #include "src/messages.h"
@@ skipping 346 matching lines @@
 
 
 class StoreIC : public IC {
  public:
   StoreIC(FrameDepth depth, Isolate* isolate, FeedbackNexus* nexus = NULL)
       : IC(depth, isolate, nexus) {
     DCHECK(IsStoreStub());
   }
 
   LanguageMode language_mode() const {
-    return StoreICState::GetLanguageMode(extra_ic_state());
+    return nexus()->vector()->GetLanguageMode(nexus()->slot());
   }
 
   MUST_USE_RESULT MaybeHandle<Object> Store(
       Handle<Object> object, Handle<Name> name, Handle<Object> value,
       JSReceiver::StoreFromKeyed store_mode =
           JSReceiver::CERTAINLY_NOT_STORE_FROM_KEYED);
 
   bool LookupForWrite(LookupIterator* it, Handle<Object> value,
                       JSReceiver::StoreFromKeyed store_mode);
 
   static void Clear(Isolate* isolate, Code* host, StoreICNexus* nexus);
 
  protected:
   // Stub accessors.
   Handle<Code> slow_stub() const {
+    // TODO(ishell): don't hard-code language mode into the handler because
+    // this handler can be re-used through megamorphic stub cache for wrong
+    // language mode.
+    // The slow stub must decode the language mode from the IC kind.
     switch (language_mode()) {
       case SLOPPY:
         return isolate()->builtins()->StoreIC_SlowSloppy();
       case STRICT:
         return isolate()->builtins()->StoreIC_SlowStrict();
       default:
         UNREACHABLE();
         return Handle<Code>();
     }
   }
@@ skipping 104 matching lines @@
 
 // Helper for BinaryOpIC and CompareIC.
 enum InlinedSmiCheck { ENABLE_INLINED_SMI_CHECK, DISABLE_INLINED_SMI_CHECK };
 void PatchInlinedSmiCode(Isolate* isolate, Address address,
                          InlinedSmiCheck check);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IC_H_