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