Re-reland: Remove register index/code indirection

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index ea837dca4b014f4397428cdecc65db08b81cc42f..f41da95da76e9601bf11f96aed31cbb9ccfef601 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -10,6 +10,7 @@
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/heap/heap.h"
+#include "src/register-configuration.h"
 #include "src/x64/assembler-x64.h"
 #include "src/x64/macro-assembler-x64.h"
 
@@ -729,7 +730,8 @@ void MacroAssembler::GetBuiltinEntry(Register target,
 }
 
 
-#define REG(Name) { kRegister_ ## Name ## _Code }
+#define REG(Name) \
+  { Register::kCode_##Name }
 
 static const Register saved_regs[] = {
   REG(rax), REG(rcx), REG(rdx), REG(rbx), REG(rbp), REG(rsi), REG(rdi), REG(r8),
@@ -3710,12 +3712,14 @@ void MacroAssembler::EnterExitFrameEpilogue(int arg_stack_space,
 #endif
   // Optionally save all XMM registers.
   if (save_doubles) {
-    int space = XMMRegister::kMaxNumAllocatableRegisters * kDoubleSize +
-        arg_stack_space * kRegisterSize;
+    int space = XMMRegister::kMaxNumRegisters * kDoubleSize +
+                arg_stack_space * kRegisterSize;
     subp(rsp, Immediate(space));
     int offset = -2 * kPointerSize;
-    for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); i++) {
-      XMMRegister reg = XMMRegister::FromAllocationIndex(i);
+    const RegisterConfiguration* config = RegisterConfiguration::ArchDefault();
+    for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
+      DoubleRegister reg =
+          DoubleRegister::from_code(config->GetAllocatableDoubleCode(i));
       movsd(Operand(rbp, offset - ((i + 1) * kDoubleSize)), reg);
     }
   } else if (arg_stack_space > 0) {
@@ -3758,8 +3762,10 @@ void MacroAssembler::LeaveExitFrame(bool save_doubles) {
   // r15 : argv
   if (save_doubles) {
     int offset = -2 * kPointerSize;
-    for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); i++) {
-      XMMRegister reg = XMMRegister::FromAllocationIndex(i);
+    const RegisterConfiguration* config = RegisterConfiguration::ArchDefault();
+    for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
+      DoubleRegister reg =
+          DoubleRegister::from_code(config->GetAllocatableDoubleCode(i));
       movsd(reg, Operand(rbp, offset - ((i + 1) * kDoubleSize)));
     }
   }