[strong] Implement strong mode restrictions on property access

src/ic/ic-state.h

Index: src/ic/ic-state.h
diff --git a/src/ic/ic-state.h b/src/ic/ic-state.h
index dbc504bf6d79f9f95d6a86e14eca0514198507f5..89e455deb786e35edc7034b5d5ebb4750261b2d9 100644
--- a/src/ic/ic-state.h
+++ b/src/ic/ic-state.h
@@ -201,11 +201,21 @@ class CompareICState {
 
 
 class LoadICState final BASE_EMBEDDED {
+ private:
+  class ContextualModeBits : public BitField<ContextualMode, 0, 1> {};
+  class LanguageModeBits : public BitField<LanguageMode, 1, 2> {};
+  STATIC_ASSERT(static_cast<int>(NOT_CONTEXTUAL) == 0);
+  const ExtraICState state_;
+
  public:
+  static const ExtraICState kStrongModeState = STRONG
+                                               << LanguageModeBits::kShift;
+
   explicit LoadICState(ExtraICState extra_ic_state) : state_(extra_ic_state) {}
 
-  explicit LoadICState(ContextualMode mode)
-      : state_(ContextualModeBits::encode(mode)) {}
+  explicit LoadICState(ContextualMode mode, LanguageMode language_mode)
+      : state_(ContextualModeBits::encode(mode) |
+               LanguageModeBits::encode(language_mode)) {}
 
   ExtraICState GetExtraICState() const { return state_; }
 
@@ -213,15 +223,17 @@ class LoadICState final BASE_EMBEDDED {
     return ContextualModeBits::decode(state_);
   }
 
+  LanguageMode language_mode() const {
+    return LanguageModeBits::decode(state_);
+  }
+
   static ContextualMode GetContextualMode(ExtraICState state) {
     return LoadICState(state).contextual_mode();
   }
 
- private:
-  class ContextualModeBits : public BitField<ContextualMode, 0, 1> {};
-  STATIC_ASSERT(static_cast<int>(NOT_CONTEXTUAL) == 0);
-
-  const ExtraICState state_;
+  static LanguageMode GetLanguageMode(ExtraICState state) {
+    return LoadICState(state).language_mode();
+  }
 };