X64 Crankshaft: Ported lots of boilerplate code.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index 7bcc7c56dd873786c6e86deb1c190a24303b9686..6822c1c3ad0304b8c3f04d18ca6d72eb1db6139d 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -98,6 +98,16 @@ struct Register {
   static const int kNumRegisters = 16;
   static const int kNumAllocatableRegisters = 10;
 
+  static int ToAllocationIndex(Register reg) {
+    return allocationIndexByRegisterCode[reg.code()];
+  }
+
+  static Register FromAllocationIndex(int index) {
+    ASSERT(index >= 0 && index < kNumAllocatableRegisters);
+    Register result = { registerCodeByAllocationIndex[index] };
+    return result;
+  }
+
   static const char* AllocationIndexToString(int index) {
     ASSERT(index >= 0 && index < kNumAllocatableRegisters);
     const char* const names[] = {
@@ -143,6 +153,9 @@ struct Register {
   // Unfortunately we can't make this private in a struct when initializing
   // by assignment.
   int code_;
+ private:
+  static const int registerCodeByAllocationIndex[kNumAllocatableRegisters];
+  static const int allocationIndexByRegisterCode[kNumRegisters];
 };
 
 const Register rax = { 0 };
@@ -173,6 +186,12 @@ struct XMMRegister {
     return reg.code() - 1;
   }
 
+  static XMMRegister FromAllocationIndex(int index) {
+    ASSERT(0 <= index && index < kNumAllocatableRegisters);
+    XMMRegister result = { index + 1 };
+    return result;
+  }
+
   static const char* AllocationIndexToString(int index) {
     ASSERT(index >= 0 && index < kNumAllocatableRegisters);
     const char* const names[] = {