Re-reland: Remove register index/code indirection

src/ia32/lithium-gap-resolver-ia32.cc

Index: src/ia32/lithium-gap-resolver-ia32.cc
diff --git a/src/ia32/lithium-gap-resolver-ia32.cc b/src/ia32/lithium-gap-resolver-ia32.cc
index 0926a0f21a1d4b0a873998232e3a8d501a880d1a..655f4a2efb71e633fe62b2d06b9d91c7817a5145 100644
--- a/src/ia32/lithium-gap-resolver-ia32.cc
+++ b/src/ia32/lithium-gap-resolver-ia32.cc
@@ -6,6 +6,7 @@
 
 #include "src/ia32/lithium-codegen-ia32.h"
 #include "src/ia32/lithium-gap-resolver-ia32.h"
+#include "src/register-configuration.h"
 
 namespace v8 {
 namespace internal {
@@ -165,10 +166,13 @@ int LGapResolver::CountSourceUses(LOperand* operand) {
 
 
 Register LGapResolver::GetFreeRegisterNot(Register reg) {
-  int skip_index = reg.is(no_reg) ? -1 : Register::ToAllocationIndex(reg);
-  for (int i = 0; i < Register::NumAllocatableRegisters(); ++i) {
-    if (source_uses_[i] == 0 && destination_uses_[i] > 0 && i != skip_index) {
-      return Register::FromAllocationIndex(i);
+  int skip_index = reg.is(no_reg) ? -1 : reg.code();
+  const RegisterConfiguration* config = RegisterConfiguration::ArchDefault();
+  for (int i = 0; i < config->num_allocatable_general_registers(); ++i) {
+    int code = config->GetAllocatableGeneralCode(i);
+    if (source_uses_[code] == 0 && destination_uses_[code] > 0 &&
+        code != skip_index) {
+      return Register::from_code(code);
     }
   }
   return no_reg;
@@ -178,10 +182,11 @@ Register LGapResolver::GetFreeRegisterNot(Register reg) {
 bool LGapResolver::HasBeenReset() {
   if (!moves_.is_empty()) return false;
   if (spilled_register_ >= 0) return false;
-
-  for (int i = 0; i < Register::NumAllocatableRegisters(); ++i) {
-    if (source_uses_[i] != 0) return false;
-    if (destination_uses_[i] != 0) return false;
+  const RegisterConfiguration* config = RegisterConfiguration::ArchDefault();
+  for (int i = 0; i < config->num_allocatable_general_registers(); ++i) {
+    int code = config->GetAllocatableGeneralCode(i);
+    if (source_uses_[code] != 0) return false;
+    if (destination_uses_[code] != 0) return false;
   }
   return true;
 }
@@ -204,7 +209,7 @@ void LGapResolver::Verify() {
 
 void LGapResolver::Finish() {
   if (spilled_register_ >= 0) {
-    __ pop(Register::FromAllocationIndex(spilled_register_));
+    __ pop(Register::from_code(spilled_register_));
     spilled_register_ = -1;
   }
   moves_.Rewind(0);
@@ -213,7 +218,7 @@ void LGapResolver::Finish() {
 
 void LGapResolver::EnsureRestored(LOperand* operand) {
   if (operand->IsRegister() && operand->index() == spilled_register_) {
-    __ pop(Register::FromAllocationIndex(spilled_register_));
+    __ pop(Register::from_code(spilled_register_));
     spilled_register_ = -1;
   }
 }
@@ -222,7 +227,7 @@ void LGapResolver::EnsureRestored(LOperand* operand) {
 Register LGapResolver::EnsureTempRegister() {
   // 1. We may have already spilled to create a temp register.
   if (spilled_register_ >= 0) {
-    return Register::FromAllocationIndex(spilled_register_);
+    return Register::from_code(spilled_register_);
   }
 
   // 2. We may have a free register that we can use without spilling.
@@ -231,19 +236,21 @@ Register LGapResolver::EnsureTempRegister() {
 
   // 3. Prefer to spill a register that is not used in any remaining move
   // because it will not need to be restored until the end.
-  for (int i = 0; i < Register::NumAllocatableRegisters(); ++i) {
-    if (source_uses_[i] == 0 && destination_uses_[i] == 0) {
-      Register scratch = Register::FromAllocationIndex(i);
+  const RegisterConfiguration* config = RegisterConfiguration::ArchDefault();
+  for (int i = 0; i < config->num_allocatable_general_registers(); ++i) {
+    int code = config->GetAllocatableGeneralCode(i);
+    if (source_uses_[code] == 0 && destination_uses_[code] == 0) {
+      Register scratch = Register::from_code(code);
       __ push(scratch);
-      spilled_register_ = i;
+      spilled_register_ = code;
       return scratch;
     }
   }
 
   // 4. Use an arbitrary register.  Register 0 is as arbitrary as any other.
-  Register scratch = Register::FromAllocationIndex(0);
+  spilled_register_ = config->GetAllocatableGeneralCode(0);
+  Register scratch = Register::from_code(spilled_register_);
   __ push(scratch);
-  spilled_register_ = 0;
   return scratch;
 }