Re-reland: Remove register index/code indirection

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 956e142c9ef35649608a1cb466bbeb42da5b84c0..f1ffcd29d6c46282efa366338e05873c43e5e416 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -47,6 +47,39 @@ namespace internal {
 
 // Utility functions
 
+#define GENERAL_REGISTERS(V) \
+  V(rax)                     \
+  V(rcx)                     \
+  V(rdx)                     \
+  V(rbx)                     \
+  V(rsp)                     \
+  V(rbp)                     \
+  V(rsi)                     \
+  V(rdi)                     \
+  V(r8)                      \
+  V(r9)                      \
+  V(r10)                     \
+  V(r11)                     \
+  V(r12)                     \
+  V(r13)                     \
+  V(r14)                     \
+  V(r15)
+
+#define ALLOCATABLE_GENERAL_REGISTERS(V) \
+  V(rax)                                 \
+  V(rbx)                                 \
+  V(rdx)                                 \
+  V(rcx)                                 \
+  V(rsi)                                 \
+  V(rdi)                                 \
+  V(r8)                                  \
+  V(r9)                                  \
+  V(r11)                                 \
+  V(r12)                                 \
+  V(r14)                                 \
+  V(r15)
+
+
 // CPU Registers.
 //
 // 1) We would prefer to use an enum, but enum values are assignment-
@@ -68,226 +101,153 @@ namespace internal {
 // mode. This way we get the compile-time error checking in debug mode
 // and best performance in optimized code.
 //
-
 struct Register {
-  // The non-allocatable registers are:
-  //  rsp - stack pointer
-  //  rbp - frame pointer
-  //  r10 - fixed scratch register
-  //  r13 - root register
-  static const int kMaxNumAllocatableRegisters = 12;
-  static int NumAllocatableRegisters() {
-    return kMaxNumAllocatableRegisters;
-  }
-  static const int kNumRegisters = 16;
-
-  static int ToAllocationIndex(Register reg) {
-    return kAllocationIndexByRegisterCode[reg.code()];
-  }
-
-  static Register FromAllocationIndex(int index) {
-    DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
-    Register result = { kRegisterCodeByAllocationIndex[index] };
-    return result;
-  }
+  enum Code {
+#define REGISTER_CODE(R) kCode_##R,
+    GENERAL_REGISTERS(REGISTER_CODE)
+#undef REGISTER_CODE
+        kAfterLast,
+    kCode_no_reg = -1
+  };
 
-  static const char* AllocationIndexToString(int index) {
-    DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
-    const char* const names[] = {
-      "rax",
-      "rbx",
-      "rdx",
-      "rcx",
-      "rsi",
-      "rdi",
-      "r8",
-      "r9",
-      "r11",
-      "r12",
-      "r14",
-      "r15"
-    };
-    return names[index];
-  }
+  static const int kNumRegisters = Code::kAfterLast;
 
   static Register from_code(int code) {
-    Register r = { 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_; }
-  // rax, rbx, rcx and rdx are byte registers, the rest are not.
-  bool is_byte_register() const { return code_ <= 3; }
+  const char* ToString();
+  bool IsAllocatable() const;
+  bool is_valid() const { return 0 <= reg_code && reg_code < kNumRegisters; }
+  bool is(Register reg) const { return reg_code == reg.reg_code; }
   int code() const {
     DCHECK(is_valid());
-    return code_;
+    return reg_code;
   }
   int bit() const {
-    return 1 << code_;
+    DCHECK(is_valid());
+    return 1 << reg_code;
   }
 
+  bool is_byte_register() const { return reg_code <= 3; }
   // Return the high bit of the register code as a 0 or 1.  Used often
   // when constructing the REX prefix byte.
-  int high_bit() const {
-    return code_ >> 3;
-  }
+  int high_bit() const { return reg_code >> 3; }
   // Return the 3 low bits of the register code.  Used when encoding registers
   // in modR/M, SIB, and opcode bytes.
-  int low_bits() const {
-    return code_ & 0x7;
-  }
+  int low_bits() const { return reg_code & 0x7; }
 
   // Unfortunately we can't make this private in a struct when initializing
   // by assignment.
-  int code_;
-
- private:
-  static const int kRegisterCodeByAllocationIndex[kMaxNumAllocatableRegisters];
-  static const int kAllocationIndexByRegisterCode[kNumRegisters];
+  int reg_code;
 };
 
-const int kRegister_rax_Code = 0;
-const int kRegister_rcx_Code = 1;
-const int kRegister_rdx_Code = 2;
-const int kRegister_rbx_Code = 3;
-const int kRegister_rsp_Code = 4;
-const int kRegister_rbp_Code = 5;
-const int kRegister_rsi_Code = 6;
-const int kRegister_rdi_Code = 7;
-const int kRegister_r8_Code = 8;
-const int kRegister_r9_Code = 9;
-const int kRegister_r10_Code = 10;
-const int kRegister_r11_Code = 11;
-const int kRegister_r12_Code = 12;
-const int kRegister_r13_Code = 13;
-const int kRegister_r14_Code = 14;
-const int kRegister_r15_Code = 15;
-const int kRegister_no_reg_Code = -1;
-
-const Register rax = { kRegister_rax_Code };
-const Register rcx = { kRegister_rcx_Code };
-const Register rdx = { kRegister_rdx_Code };
-const Register rbx = { kRegister_rbx_Code };
-const Register rsp = { kRegister_rsp_Code };
-const Register rbp = { kRegister_rbp_Code };
-const Register rsi = { kRegister_rsi_Code };
-const Register rdi = { kRegister_rdi_Code };
-const Register r8 = { kRegister_r8_Code };
-const Register r9 = { kRegister_r9_Code };
-const Register r10 = { kRegister_r10_Code };
-const Register r11 = { kRegister_r11_Code };
-const Register r12 = { kRegister_r12_Code };
-const Register r13 = { kRegister_r13_Code };
-const Register r14 = { kRegister_r14_Code };
-const Register r15 = { kRegister_r15_Code };
-const Register no_reg = { kRegister_no_reg_Code };
+
+#define DECLARE_REGISTER(R) const Register R = {Register::kCode_##R};
+GENERAL_REGISTERS(DECLARE_REGISTER)
+#undef DECLARE_REGISTER
+const Register no_reg = {Register::kCode_no_reg};
+
 
 #ifdef _WIN64
   // Windows calling convention
-  const Register arg_reg_1 = { kRegister_rcx_Code };
-  const Register arg_reg_2 = { kRegister_rdx_Code };
-  const Register arg_reg_3 = { kRegister_r8_Code };
-  const Register arg_reg_4 = { kRegister_r9_Code };
+const Register arg_reg_1 = {Register::kCode_rcx};
+const Register arg_reg_2 = {Register::kCode_rdx};
+const Register arg_reg_3 = {Register::kCode_r8};
+const Register arg_reg_4 = {Register::kCode_r9};
 #else
   // AMD64 calling convention
-  const Register arg_reg_1 = { kRegister_rdi_Code };
-  const Register arg_reg_2 = { kRegister_rsi_Code };
-  const Register arg_reg_3 = { kRegister_rdx_Code };
-  const Register arg_reg_4 = { kRegister_rcx_Code };
+const Register arg_reg_1 = {Register::kCode_rdi};
+const Register arg_reg_2 = {Register::kCode_rsi};
+const Register arg_reg_3 = {Register::kCode_rdx};
+const Register arg_reg_4 = {Register::kCode_rcx};
 #endif  // _WIN64
 
-struct XMMRegister {
-  static const int kMaxNumRegisters = 16;
-  static const int kMaxNumAllocatableRegisters = 15;
-  static int NumAllocatableRegisters() {
-    return kMaxNumAllocatableRegisters;
-  }
-
-  // TODO(turbofan): Proper support for float32.
-  static int NumAllocatableAliasedRegisters() {
-    return NumAllocatableRegisters();
-  }
-
-  static int ToAllocationIndex(XMMRegister reg) {
-    DCHECK(reg.code() != 0);
-    return reg.code() - 1;
-  }
 
-  static XMMRegister FromAllocationIndex(int index) {
-    DCHECK(0 <= index && index < kMaxNumAllocatableRegisters);
-    XMMRegister result = { index + 1 };
+#define DOUBLE_REGISTERS(V) \
+  V(xmm0)                   \
+  V(xmm1)                   \
+  V(xmm2)                   \
+  V(xmm3)                   \
+  V(xmm4)                   \
+  V(xmm5)                   \
+  V(xmm6)                   \
+  V(xmm7)                   \
+  V(xmm8)                   \
+  V(xmm9)                   \
+  V(xmm10)                  \
+  V(xmm11)                  \
+  V(xmm12)                  \
+  V(xmm13)                  \
+  V(xmm14)                  \
+  V(xmm15)
+
+#define ALLOCATABLE_DOUBLE_REGISTERS(V) \
+  V(xmm1)                               \
+  V(xmm2)                               \
+  V(xmm3)                               \
+  V(xmm4)                               \
+  V(xmm5)                               \
+  V(xmm6)                               \
+  V(xmm7)                               \
+  V(xmm8)                               \
+  V(xmm9)                               \
+  V(xmm10)                              \
+  V(xmm11)                              \
+  V(xmm12)                              \
+  V(xmm13)                              \
+  V(xmm14)                              \
+  V(xmm15)
+
+
+struct DoubleRegister {
+  enum Code {
+#define REGISTER_CODE(R) kCode_##R,
+    DOUBLE_REGISTERS(REGISTER_CODE)
+#undef REGISTER_CODE
+        kAfterLast,
+    kCode_no_reg = -1
+  };
+
+  static const int kMaxNumRegisters = Code::kAfterLast;
+
+  static DoubleRegister from_code(int code) {
+    DoubleRegister result = {code};
     return result;
   }
 
-  static const char* AllocationIndexToString(int index) {
-    DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
-    const char* const names[] = {
-      "xmm1",
-      "xmm2",
-      "xmm3",
-      "xmm4",
-      "xmm5",
-      "xmm6",
-      "xmm7",
-      "xmm8",
-      "xmm9",
-      "xmm10",
-      "xmm11",
-      "xmm12",
-      "xmm13",
-      "xmm14",
-      "xmm15"
-    };
-    return names[index];
-  }
-
-  static XMMRegister from_code(int code) {
-    DCHECK(code >= 0);
-    DCHECK(code < kMaxNumRegisters);
-    XMMRegister r = { code };
-    return r;
-  }
-  bool is_valid() const { return 0 <= code_ && code_ < kMaxNumRegisters; }
-  bool is(XMMRegister reg) const { return code_ == reg.code_; }
+  const char* ToString();
+  bool IsAllocatable() const;
+  bool is_valid() const { return 0 <= reg_code && reg_code < kMaxNumRegisters; }
+  bool is(DoubleRegister reg) const { return reg_code == reg.reg_code; }
   int code() const {
     DCHECK(is_valid());
-    return code_;
+    return reg_code;
   }
 
   // Return the high bit of the register code as a 0 or 1.  Used often
   // when constructing the REX prefix byte.
-  int high_bit() const {
-    return code_ >> 3;
-  }
+  int high_bit() const { return reg_code >> 3; }
   // Return the 3 low bits of the register code.  Used when encoding registers
   // in modR/M, SIB, and opcode bytes.
-  int low_bits() const {
-    return code_ & 0x7;
-  }
+  int low_bits() const { return reg_code & 0x7; }
 
-  int code_;
+  // Unfortunately we can't make this private in a struct when initializing
+  // by assignment.
+  int reg_code;
 };
 
-const XMMRegister xmm0 = { 0 };
-const XMMRegister xmm1 = { 1 };
-const XMMRegister xmm2 = { 2 };
-const XMMRegister xmm3 = { 3 };
-const XMMRegister xmm4 = { 4 };
-const XMMRegister xmm5 = { 5 };
-const XMMRegister xmm6 = { 6 };
-const XMMRegister xmm7 = { 7 };
-const XMMRegister xmm8 = { 8 };
-const XMMRegister xmm9 = { 9 };
-const XMMRegister xmm10 = { 10 };
-const XMMRegister xmm11 = { 11 };
-const XMMRegister xmm12 = { 12 };
-const XMMRegister xmm13 = { 13 };
-const XMMRegister xmm14 = { 14 };
-const XMMRegister xmm15 = { 15 };
-
-
-typedef XMMRegister DoubleRegister;
 
+#define DECLARE_REGISTER(R) \
+  const DoubleRegister R = {DoubleRegister::kCode_##R};
+DOUBLE_REGISTERS(DECLARE_REGISTER)
+#undef DECLARE_REGISTER
+const DoubleRegister no_double_reg = {DoubleRegister::kCode_no_reg};
+
+
+typedef DoubleRegister XMMRegister;
 
 enum Condition {
   // any value < 0 is considered no_condition