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

test/cctest/compiler/test-multiple-return.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 <cmath>
 #include <functional>
 #include <limits>
 
 #include "src/assembler.h"
 #include "src/base/bits.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/codegen.h"
 #include "src/compiler.h"
 #include "src/compiler/linkage.h"
 #include "src/macro-assembler.h"
 #include "test/cctest/cctest.h"
 #include "test/cctest/compiler/codegen-tester.h"
 #include "test/cctest/compiler/value-helper.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 namespace {
 
 CallDescriptor* GetCallDescriptor(Zone* zone, int return_count,
                                   int param_count) {
   MachineSignature::Builder msig(zone, return_count, param_count);
   LocationSignature::Builder locations(zone, return_count, param_count);
-  const RegisterConfiguration* config =
-      RegisterConfiguration::ArchDefault(RegisterConfiguration::TURBOFAN);
+  const RegisterConfiguration* config = RegisterConfiguration::Turbofan();
 
   // Add return location(s).
   CHECK(return_count <= config->num_allocatable_general_registers());
   for (int i = 0; i < return_count; i++) {
     msig.AddReturn(MachineType::Int32());
     locations.AddReturn(
         LinkageLocation::ForRegister(config->allocatable_general_codes()[i]));
   }
 
   // Add register and/or stack parameter(s).
@@ skipping 69 matching lines @@
     OFStream os(stdout);
     code2->Disassemble("three_value_call", os);
   }
 #endif
   CHECK_EQ((123 + 456) + (123 - 456) + (123 * 456), mt.Call());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8