1 //===-- llvm/MC/Register.h --------------------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_MC_MCREGISTER_H 10 #define LLVM_MC_MCREGISTER_H 11 12 #include "llvm/ADT/DenseMapInfo.h" 13 #include "llvm/ADT/Hashing.h" 14 #include <cassert> 15 #include <limits> 16 17 namespace llvm { 18 19 /// An unsigned integer type large enough to represent all physical registers, 20 /// but not necessarily virtual registers. 21 using MCPhysReg = uint16_t; 22 23 /// Wrapper class representing physical registers. Should be passed by value. 24 class MCRegister { 25 friend hash_code hash_value(const MCRegister &); 26 unsigned Reg; 27 28 public: 29 constexpr MCRegister(unsigned Val = 0): Reg(Val) {} 30 31 // Register numbers can represent physical registers, virtual registers, and 32 // sometimes stack slots. The unsigned values are divided into these ranges: 33 // 34 // 0 Not a register, can be used as a sentinel. 35 // [1;2^30) Physical registers assigned by TableGen. 36 // [2^30;2^31) Stack slots. (Rarely used.) 37 // [2^31;2^32) Virtual registers assigned by MachineRegisterInfo. 38 // 39 // Further sentinels can be allocated from the small negative integers. 40 // DenseMapInfo<unsigned> uses -1u and -2u. 41 static_assert(std::numeric_limits<decltype(Reg)>::max() >= 0xFFFFFFFF, 42 "Reg isn't large enough to hold full range."); 43 static constexpr unsigned NoRegister = 0u; 44 static constexpr unsigned FirstPhysicalReg = 1u; 45 static constexpr unsigned FirstStackSlot = 1u << 30; 46 static constexpr unsigned VirtualRegFlag = 1u << 31; 47 48 /// This is the portion of the positive number space that is not a physical 49 /// register. StackSlot values do not exist in the MC layer, see 50 /// Register::isStackSlot() for the more information on them. 51 /// 52 static bool isStackSlot(unsigned Reg) { 53 return FirstStackSlot <= Reg && Reg < VirtualRegFlag; 54 } 55 56 /// Return true if the specified register number is in 57 /// the physical register namespace. 58 static bool isPhysicalRegister(unsigned Reg) { 59 return FirstPhysicalReg <= Reg && Reg < FirstStackSlot; 60 } 61 62 constexpr operator unsigned() const { 63 return Reg; 64 } 65 66 /// Check the provided unsigned value is a valid MCRegister. 67 static MCRegister from(unsigned Val) { 68 assert(Val == NoRegister || isPhysicalRegister(Val)); 69 return MCRegister(Val); 70 } 71 72 unsigned id() const { 73 return Reg; 74 } 75 76 bool isValid() const { return Reg != NoRegister; } 77 78 /// Comparisons between register objects 79 bool operator==(const MCRegister &Other) const { return Reg == Other.Reg; } 80 bool operator!=(const MCRegister &Other) const { return Reg != Other.Reg; } 81 82 /// Comparisons against register constants. E.g. 83 /// * R == AArch64::WZR 84 /// * R == 0 85 /// * R == VirtRegMap::NO_PHYS_REG 86 bool operator==(unsigned Other) const { return Reg == Other; } 87 bool operator!=(unsigned Other) const { return Reg != Other; } 88 bool operator==(int Other) const { return Reg == unsigned(Other); } 89 bool operator!=(int Other) const { return Reg != unsigned(Other); } 90 // MSVC requires that we explicitly declare these two as well. 91 bool operator==(MCPhysReg Other) const { return Reg == unsigned(Other); } 92 bool operator!=(MCPhysReg Other) const { return Reg != unsigned(Other); } 93 }; 94 95 // Provide DenseMapInfo for MCRegister 96 template<> struct DenseMapInfo<MCRegister> { 97 static inline unsigned getEmptyKey() { 98 return DenseMapInfo<unsigned>::getEmptyKey(); 99 } 100 static inline unsigned getTombstoneKey() { 101 return DenseMapInfo<unsigned>::getTombstoneKey(); 102 } 103 static unsigned getHashValue(const MCRegister &Val) { 104 return DenseMapInfo<unsigned>::getHashValue(Val.id()); 105 } 106 static bool isEqual(const MCRegister &LHS, const MCRegister &RHS) { 107 return DenseMapInfo<unsigned>::isEqual(LHS.id(), RHS.id()); 108 } 109 }; 110 111 inline hash_code hash_value(const MCRegister &Reg) { 112 return hash_value(Reg.id()); 113 } 114 } 115 116 #endif // LLVM_MC_MCREGISTER_H 117