[turbofan] Lower JSLoadMessage/JSStoreMessage earlier.

src/compiler/access-builder.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_ACCESS_BUILDER_H_
 #define V8_COMPILER_ACCESS_BUILDER_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/compiler/simplified-operator.h"
 #include "src/elements-kind.h"
 #include "src/globals.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // This access builder provides a set of static methods constructing commonly
 // used FieldAccess and ElementAccess descriptors. These descriptors serve as
 // parameters to simplified load/store operators.
 class V8_EXPORT_PRIVATE AccessBuilder final
     : public NON_EXPORTED_BASE(AllStatic) {
  public:
   // ===========================================================================
   // Access to external values (based on external references).
 
   // Provides access to a double field identified by an external reference.
   static FieldAccess ForExternalDoubleValue();
 
+  // Provides access to a tagged field identified by an external reference.
+  static FieldAccess ForExternalTaggedValue();
+
   // Provides access to an uint8 field identified by an external reference.
   static FieldAccess ForExternalUint8Value();
 
   // ===========================================================================
   // Access to heap object fields and elements (based on tagged pointer).
 
   // Provides access to HeapObject::map() field.
   static FieldAccess ForMap();
 
   // Provides access to HeapNumber::value() field.
@@ skipping 216 matching lines @@
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AccessBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_ACCESS_BUILDER_H_