[RegisterConfiguration] Streamline access to arch defaults, simplify Registers.

src/crankshaft/s390/lithium-codegen-s390.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 "src/crankshaft/s390/lithium-codegen-s390.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 3700 matching lines @@
                                   Register scratch3) {
 #if DEBUG
   if (actual.is_reg()) {
     DCHECK(!AreAliased(actual.reg(), scratch1, scratch2, scratch3));
   } else {
     DCHECK(!AreAliased(scratch1, scratch2, scratch3));
   }
 #endif
   if (FLAG_code_comments) {
     if (actual.is_reg()) {
-      Comment(";;; PrepareForTailCall, actual: %s {", actual.reg().ToString());
+      Comment(";;; PrepareForTailCall, actual: %s {",
+              RegisterConfiguration::Crankshaft()->GetGeneralRegisterName(
+                  actual.reg().code()));
     } else {
       Comment(";;; PrepareForTailCall, actual: %d {", actual.immediate());
     }
   }
 
   // Check if next frame is an arguments adaptor frame.
   Register caller_args_count_reg = scratch1;
   Label no_arguments_adaptor, formal_parameter_count_loaded;
   __ LoadP(scratch2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
   __ LoadP(scratch3,
@@ skipping 1952 matching lines @@
   __ LoadP(result,
            FieldMemOperand(scratch, FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8