Revert of Reland: Remove register index/code indirection

src/x87/assembler-x87.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 58 matching lines @@
 //
 struct Register {
   static const int kMaxNumAllocatableRegisters = 6;
   static int NumAllocatableRegisters() {
     return kMaxNumAllocatableRegisters;
   }
   static const int kNumRegisters = 8;
 
   static inline const char* AllocationIndexToString(int index);
 
+  static inline int ToAllocationIndex(Register reg);
+
+  static inline Register FromAllocationIndex(int index);
+
   static Register from_code(int code) {
     DCHECK(code >= 0);
     DCHECK(code < kNumRegisters);
     Register r = { code };
     return r;
   }
   bool is_valid() const { return 0 <= code_ && code_ < kNumRegisters; }
   bool is(Register reg) const { return code_ == reg.code_; }
   // eax, ebx, ecx and edx are byte registers, the rest are not.
   bool is_byte_register() const { return code_ <= 3; }
@@ skipping 32 matching lines @@
 
 
 inline const char* Register::AllocationIndexToString(int index) {
   DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
   // This is the mapping of allocation indices to registers.
   const char* const kNames[] = { "eax", "ecx", "edx", "ebx", "esi", "edi" };
   return kNames[index];
 }
 
 
+inline int Register::ToAllocationIndex(Register reg) {
+  DCHECK(reg.is_valid() && !reg.is(esp) && !reg.is(ebp));
+  return (reg.code() >= 6) ? reg.code() - 2 : reg.code();
+}
+
+
+inline Register Register::FromAllocationIndex(int index)  {
+  DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
+  return (index >= 4) ? from_code(index + 2) : from_code(index);
+}
+
+
 struct X87Register {
   static const int kMaxNumAllocatableRegisters = 6;
   static const int kMaxNumRegisters = 8;
   static int NumAllocatableRegisters() {
     return kMaxNumAllocatableRegisters;
   }
 
 
   // TODO(turbofan): Proper support for float32.
   static int NumAllocatableAliasedRegisters() {
@@ skipping 937 matching lines @@
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X87_ASSEMBLER_X87_H_