[compiler] Drop the CompareNilIC.

src/types.cc

 // Copyright 2014 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.
 
 #include <iomanip>
 
 #include "src/types.h"
 
 #include "src/handles-inl.h"
 #include "src/ostreams.h"
@@ skipping 201 matching lines @@
     case JS_TYPED_ARRAY_TYPE:
     case JS_DATA_VIEW_TYPE:
     case JS_SET_TYPE:
     case JS_MAP_TYPE:
     case JS_SET_ITERATOR_TYPE:
     case JS_MAP_ITERATOR_TYPE:
     case JS_WEAK_MAP_TYPE:
     case JS_WEAK_SET_TYPE:
     case JS_PROMISE_TYPE:
     case JS_BOUND_FUNCTION_TYPE:
-      if (map->is_undetectable()) return kUndetectable;
+      if (map->is_undetectable()) return kOtherUndetectable;
       return kOtherObject;
     case JS_FUNCTION_TYPE:
-      if (map->is_undetectable()) return kUndetectable;
+      if (map->is_undetectable()) return kOtherUndetectable;
       return kFunction;
     case JS_REGEXP_TYPE:
       return kOtherObject;  // TODO(rossberg): there should be a RegExp type.
     case JS_PROXY_TYPE:
       return kProxy;
     case MAP_TYPE:
-      // When compiling stub templates, the meta map is used as a place holder
-      // for the actual map with which the template is later instantiated.
-      // We treat it as a kind of type variable whose upper bound is Any.
-      // TODO(rossberg): for caching of CompareNilIC stubs to work correctly,
-      // we must exclude Undetectable here. This makes no sense, really,
-      // because it means that the template isn't actually parametric.
-      // Also, it doesn't apply elsewhere. 8-(
-      // We ought to find a cleaner solution for compiling stubs parameterised
-      // over type or class variables, esp ones with bounds...
-      return kDetectable & kTaggedPointer;
     case ALLOCATION_SITE_TYPE:
     case ACCESSOR_INFO_TYPE:
     case SHARED_FUNCTION_INFO_TYPE:
     case ACCESSOR_PAIR_TYPE:
     case FIXED_ARRAY_TYPE:
     case FIXED_DOUBLE_ARRAY_TYPE:
     case BYTE_ARRAY_TYPE:
     case BYTECODE_ARRAY_TYPE:
     case TRANSITION_ARRAY_TYPE:
     case FOREIGN_TYPE:
@@ skipping 1022 matching lines @@
 #undef CONSTRUCT_SIMD_TYPE
 
 // -----------------------------------------------------------------------------
 // Instantiations.
 
 template class Type::Iterator<i::Map>;
 template class Type::Iterator<i::Object>;
 
 }  // namespace internal
 }  // namespace v8