[turbofan] Make FieldAccess::name usable in practice.

src/compiler/simplified-operator.h

 // 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.
 
 #ifndef V8_COMPILER_SIMPLIFIED_OPERATOR_H_
 #define V8_COMPILER_SIMPLIFIED_OPERATOR_H_
 
 #include <iosfwd>
 
 #include "src/handles.h"
@@ skipping 45 matching lines @@
 
 BufferAccess const BufferAccessOf(const Operator* op) WARN_UNUSED_RESULT;
 
 
 // An access descriptor for loads/stores of fixed structures like field
 // accesses of heap objects. Accesses from either tagged or untagged base
 // pointers are supported; untagging is done automatically during lowering.
 struct FieldAccess {
   BaseTaggedness base_is_tagged;  // specifies if the base pointer is tagged.
   int offset;                     // offset of the field, without tag.
-  MaybeHandle<Name> name;         // debugging only.
+  const char* name;               // debugging only.
   Type* type;                     // type of the field.
   MachineType machine_type;       // machine type of the field.
 
   int tag() const { return base_is_tagged == kTaggedBase ? kHeapObjectTag : 0; }
 };
 
 bool operator==(FieldAccess const&, FieldAccess const&);
 bool operator!=(FieldAccess const&, FieldAccess const&);
 
 size_t hash_value(FieldAccess const&);
@@ skipping 117 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_H_