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

src/crankshaft/lithium.cc

Index: src/crankshaft/lithium.cc
diff --git a/src/crankshaft/lithium.cc b/src/crankshaft/lithium.cc
index 5aed08718ade4a406479d278d81e3c128bdf7adf..4b3e0bc63a8d7279d37bcf42946215b5a501578d 100644
--- a/src/crankshaft/lithium.cc
+++ b/src/crankshaft/lithium.cc
@@ -40,6 +40,7 @@
 namespace v8 {
 namespace internal {
 
+const auto GetRegConfig = RegisterConfiguration::Crankshaft;
 
 void LOperand::PrintTo(StringStream* stream) {
   LUnallocated* unalloc = NULL;
@@ -63,7 +64,7 @@ void LOperand::PrintTo(StringStream* stream) {
             stream->Add("(=invalid_reg#%d)", reg_index);
           } else {
             const char* register_name =
-                Register::from_code(reg_index).ToString();
+                GetRegConfig()->GetGeneralRegisterName(reg_index);
             stream->Add("(=%s)", register_name);
           }
           break;
@@ -74,7 +75,7 @@ void LOperand::PrintTo(StringStream* stream) {
             stream->Add("(=invalid_double_reg#%d)", reg_index);
           } else {
             const char* double_register_name =
-                DoubleRegister::from_code(reg_index).ToString();
+                GetRegConfig()->GetDoubleRegisterName(reg_index);
             stream->Add("(=%s)", double_register_name);
           }
           break;
@@ -110,7 +111,8 @@ void LOperand::PrintTo(StringStream* stream) {
       if (reg_index < 0 || reg_index >= Register::kNumRegisters) {
         stream->Add("(=invalid_reg#%d|R)", reg_index);
       } else {
-        stream->Add("[%s|R]", Register::from_code(reg_index).ToString());
+        stream->Add("[%s|R]",
+                    GetRegConfig()->GetGeneralRegisterName(reg_index));
       }
       break;
     }
@@ -119,7 +121,7 @@ void LOperand::PrintTo(StringStream* stream) {
       if (reg_index < 0 || reg_index >= DoubleRegister::kMaxNumRegisters) {
         stream->Add("(=invalid_double_reg#%d|R)", reg_index);
       } else {
-        stream->Add("[%s|R]", DoubleRegister::from_code(reg_index).ToString());
+        stream->Add("[%s|R]", GetRegConfig()->GetDoubleRegisterName(reg_index));
       }
       break;
     }