Print readable register names

This adds a {PrintRegister} method which prints the given register in a
readable way (e.g. "eax", ... on ia32).
This is currently only used in Liftoff. The {RegisterConfiguration}
class has the same functionality, and I plan to make
{RegisterConfiguration} also use the new {RegisterName} functions in a
follow-up CL.

R=mstarzinger@chromium.org

Bug: v8:8238, v8:8423, v8:6600
Change-Id: If03901f1d8c5b043e0097e63920ab711bd7e2d17
Reviewed-on: https://chromium-review.googlesource.com/c/1340041
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57646}

src/arm/assembler-arm.h

@@ -1757,6 +1757,14 @@ class UseScratchRegisterScope {
   VfpRegList old_available_vfp_;
 };
 
+// Define {RegisterName} methods for the register types.
+DEFINE_REGISTER_NAMES(Register, GENERAL_REGISTERS);
+DEFINE_REGISTER_NAMES(SwVfpRegister, FLOAT_REGISTERS);
+DEFINE_REGISTER_NAMES(DwVfpRegister, DOUBLE_REGISTERS);
+DEFINE_REGISTER_NAMES(LowDwVfpRegister, LOW_DOUBLE_REGISTERS);
+DEFINE_REGISTER_NAMES(QwNeonRegister, SIMD128_REGISTERS);
+DEFINE_REGISTER_NAMES(CRegister, C_REGISTERS);
+
 }  // namespace internal
 }  // namespace v8
 

src/arm64/assembler-arm64.h

@@ -3645,6 +3645,9 @@ class EnsureSpace {
   }
 };
 
+// Define a {RegisterName} method for {CPURegister}.
+DEFINE_REGISTER_NAMES(CPURegister, GENERAL_REGISTERS);
+
 }  // namespace internal
 }  // namespace v8
 

src/assembler.h

@@ -526,10 +526,20 @@ class RegisterBase {
   int reg_code_;
 };
 
-template <typename SubType, int kAfterLastRegister>
-inline std::ostream& operator<<(std::ostream& os,
-                                RegisterBase<SubType, kAfterLastRegister> reg) {
-  return reg.is_valid() ? os << "r" << reg.code() : os << "<invalid reg>";
+// Helper macros to define a {RegisterName} method based on a macro list
+// containing all names.
+#define DEFINE_REGISTER_NAMES_NAME(name) #name,
+#define DEFINE_REGISTER_NAMES(RegType, LIST)                                   \
+  inline const char* RegisterName(RegType reg) {                               \
+    static constexpr const char* Names[] = {LIST(DEFINE_REGISTER_NAMES_NAME)}; \
+    STATIC_ASSERT(arraysize(Names) == RegType::kNumRegisters);                 \
+    return reg.is_valid() ? Names[reg.code()] : "invalid";                     \
+  }
+
+template <typename RegType,
+          typename = decltype(RegisterName(std::declval<RegType>()))>
+inline std::ostream& operator<<(std::ostream& os, RegType reg) {
+  return os << RegisterName(reg);
 }
 
 }  // namespace internal

src/ia32/assembler-ia32.h

@@ -1895,6 +1895,10 @@ class EnsureSpace {
 #endif
 };
 
+// Define {RegisterName} methods for the register types.
+DEFINE_REGISTER_NAMES(Register, GENERAL_REGISTERS)
+DEFINE_REGISTER_NAMES(XMMRegister, DOUBLE_REGISTERS)
+
 }  // namespace internal
 }  // namespace v8
 

src/mips/assembler-mips.h

@@ -2257,6 +2257,11 @@ class UseScratchRegisterScope {
   RegList old_available_;
 };
 
+// Define {RegisterName} methods for the register types.
+DEFINE_REGISTER_NAMES(Register, GENERAL_REGISTERS)
+DEFINE_REGISTER_NAMES(FPURegister, DOUBLE_REGISTERS)
+DEFINE_REGISTER_NAMES(MSARegister, SIMD128_REGISTERS)
+
 }  // namespace internal
 }  // namespace v8
 

src/mips64/assembler-mips64.h

@@ -2292,6 +2292,11 @@ class UseScratchRegisterScope {
   RegList old_available_;
 };
 
+// Define {RegisterName} methods for the register types.
+DEFINE_REGISTER_NAMES(Register, GENERAL_REGISTERS)
+DEFINE_REGISTER_NAMES(FPURegister, DOUBLE_REGISTERS)
+DEFINE_REGISTER_NAMES(MSARegister, SIMD128_REGISTERS)
+
 }  // namespace internal
 }  // namespace v8
 

src/wasm/baseline/liftoff-register.h

@@ -185,12 +185,11 @@ ASSERT_TRIVIALLY_COPYABLE(LiftoffRegister);
 
 inline std::ostream& operator<<(std::ostream& os, LiftoffRegister reg) {
   if (reg.is_pair()) {
-    return os << "<gp" << reg.low_gp().code() << "+" << reg.high_gp().code()
-              << ">";
+    return os << "<" << reg.low_gp() << "+" << reg.high_gp() << ">";
   } else if (reg.is_gp()) {
-    return os << "gp" << reg.gp().code();
+    return os << reg.gp();
   } else {
-    return os << "fp" << reg.fp().code();
+    return os << reg.fp();
   }
 }
 

src/x64/assembler-x64.h

@@ -2455,6 +2455,10 @@ class EnsureSpace {
 #endif
 };
 
+// Define {RegisterName} methods for the register types.
+DEFINE_REGISTER_NAMES(Register, GENERAL_REGISTERS)
+DEFINE_REGISTER_NAMES(XMMRegister, DOUBLE_REGISTERS)
+
 }  // namespace internal
 }  // namespace v8