Implement TDZ in StoreIC for top-level lexicals.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 5c6b5cd9b8c47acb482ca28b38869109b9d03433..14046b410d476ecf2173e928a960a51068901317 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -5327,7 +5327,7 @@ void HOptimizedGraphBuilder::VisitVariableProxy(VariableProxy* expr) {
           Handle<Context> script_context = ScriptContextTable::GetContext(
               script_contexts, lookup.context_index);
           Handle<Object> current_value =
-              FixedArray::get(script_context, lookup.context_index);
+              FixedArray::get(script_context, lookup.slot_index);
 
           // If the values is not the hole, it will stay initialized,
           // so no need to generate a check.
@@ -6488,6 +6488,16 @@ void HOptimizedGraphBuilder::HandleGlobalVariableAssignment(
       }
       Handle<Context> script_context =
           ScriptContextTable::GetContext(script_contexts, lookup.context_index);
+
+      Handle<Object> current_value =
+          FixedArray::get(script_context, lookup.slot_index);
+
+      // If the values is not the hole, it will stay initialized,
+      // so no need to generate a check.
+      if (*current_value == *isolate()->factory()->the_hole_value()) {
+        return Bailout(kReferenceToUninitializedVariable);
+      }
+
       HStoreNamedField* instr = Add<HStoreNamedField>(
           Add<HConstant>(script_context),
           HObjectAccess::ForContextSlot(lookup.slot_index), value);