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| 14 | pmbaty | 1 | //===-- llvm/CodeGen/Register.h ---------------------------------*- C++ -*-===// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |||
| 9 | #ifndef LLVM_CODEGEN_REGISTER_H |
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| 10 | #define LLVM_CODEGEN_REGISTER_H |
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| 11 | |||
| 12 | #include "llvm/MC/MCRegister.h" |
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| 13 | #include <cassert> |
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| 14 | |||
| 15 | namespace llvm { |
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| 16 | |||
| 17 | /// Wrapper class representing virtual and physical registers. Should be passed |
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| 18 | /// by value. |
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| 19 | class Register { |
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| 20 | unsigned Reg; |
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| 21 | |||
| 22 | public: |
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| 23 | constexpr Register(unsigned Val = 0): Reg(Val) {} |
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| 24 | constexpr Register(MCRegister Val): Reg(Val) {} |
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| 25 | |||
| 26 | // Register numbers can represent physical registers, virtual registers, and |
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| 27 | // sometimes stack slots. The unsigned values are divided into these ranges: |
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| 28 | // |
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| 29 | // 0 Not a register, can be used as a sentinel. |
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| 30 | // [1;2^30) Physical registers assigned by TableGen. |
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| 31 | // [2^30;2^31) Stack slots. (Rarely used.) |
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| 32 | // [2^31;2^32) Virtual registers assigned by MachineRegisterInfo. |
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| 33 | // |
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| 34 | // Further sentinels can be allocated from the small negative integers. |
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| 35 | // DenseMapInfo<unsigned> uses -1u and -2u. |
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| 36 | static_assert(std::numeric_limits<decltype(Reg)>::max() >= 0xFFFFFFFF, |
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| 37 | "Reg isn't large enough to hold full range."); |
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| 38 | |||
| 39 | /// isStackSlot - Sometimes it is useful the be able to store a non-negative |
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| 40 | /// frame index in a variable that normally holds a register. isStackSlot() |
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| 41 | /// returns true if Reg is in the range used for stack slots. |
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| 42 | /// |
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| 43 | /// FIXME: remove in favor of member. |
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| 44 | static bool isStackSlot(unsigned Reg) { |
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| 45 | return MCRegister::isStackSlot(Reg); |
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| 46 | } |
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| 47 | |||
| 48 | /// Return true if this is a stack slot. |
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| 49 | bool isStack() const { return MCRegister::isStackSlot(Reg); } |
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| 50 | |||
| 51 | /// Compute the frame index from a register value representing a stack slot. |
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| 52 | static int stackSlot2Index(Register Reg) { |
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| 53 | assert(Reg.isStack() && "Not a stack slot"); |
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| 54 | return int(Reg - MCRegister::FirstStackSlot); |
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| 55 | } |
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| 56 | |||
| 57 | /// Convert a non-negative frame index to a stack slot register value. |
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| 58 | static Register index2StackSlot(int FI) { |
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| 59 | assert(FI >= 0 && "Cannot hold a negative frame index."); |
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| 60 | return Register(FI + MCRegister::FirstStackSlot); |
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| 61 | } |
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| 62 | |||
| 63 | /// Return true if the specified register number is in |
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| 64 | /// the physical register namespace. |
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| 65 | static bool isPhysicalRegister(unsigned Reg) { |
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| 66 | return MCRegister::isPhysicalRegister(Reg); |
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| 67 | } |
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| 68 | |||
| 69 | /// Return true if the specified register number is in |
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| 70 | /// the virtual register namespace. |
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| 71 | static bool isVirtualRegister(unsigned Reg) { |
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| 72 | return Reg & MCRegister::VirtualRegFlag; |
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| 73 | } |
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| 74 | |||
| 75 | /// Convert a virtual register number to a 0-based index. |
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| 76 | /// The first virtual register in a function will get the index 0. |
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| 77 | static unsigned virtReg2Index(Register Reg) { |
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| 78 | assert(Reg.isVirtual() && "Not a virtual register"); |
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| 79 | return Reg & ~MCRegister::VirtualRegFlag; |
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| 80 | } |
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| 81 | |||
| 82 | /// Convert a 0-based index to a virtual register number. |
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| 83 | /// This is the inverse operation of VirtReg2IndexFunctor below. |
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| 84 | static Register index2VirtReg(unsigned Index) { |
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| 85 | assert(Index < (1u << 31) && "Index too large for virtual register range."); |
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| 86 | return Index | MCRegister::VirtualRegFlag; |
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| 87 | } |
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| 88 | |||
| 89 | /// Return true if the specified register number is in the virtual register |
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| 90 | /// namespace. |
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| 91 | bool isVirtual() const { |
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| 92 | return isVirtualRegister(Reg); |
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| 93 | } |
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| 94 | |||
| 95 | /// Return true if the specified register number is in the physical register |
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| 96 | /// namespace. |
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| 97 | bool isPhysical() const { |
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| 98 | return isPhysicalRegister(Reg); |
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| 99 | } |
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| 100 | |||
| 101 | /// Convert a virtual register number to a 0-based index. The first virtual |
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| 102 | /// register in a function will get the index 0. |
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| 103 | unsigned virtRegIndex() const { |
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| 104 | return virtReg2Index(Reg); |
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| 105 | } |
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| 106 | |||
| 107 | constexpr operator unsigned() const { |
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| 108 | return Reg; |
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| 109 | } |
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| 110 | |||
| 111 | unsigned id() const { return Reg; } |
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| 112 | |||
| 113 | operator MCRegister() const { |
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| 114 | return MCRegister(Reg); |
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| 115 | } |
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| 116 | |||
| 117 | /// Utility to check-convert this value to a MCRegister. The caller is |
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| 118 | /// expected to have already validated that this Register is, indeed, |
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| 119 | /// physical. |
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| 120 | MCRegister asMCReg() const { |
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| 121 | assert(Reg == MCRegister::NoRegister || |
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| 122 | MCRegister::isPhysicalRegister(Reg)); |
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| 123 | return MCRegister(Reg); |
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| 124 | } |
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| 125 | |||
| 126 | bool isValid() const { return Reg != MCRegister::NoRegister; } |
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| 127 | |||
| 128 | /// Comparisons between register objects |
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| 129 | bool operator==(const Register &Other) const { return Reg == Other.Reg; } |
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| 130 | bool operator!=(const Register &Other) const { return Reg != Other.Reg; } |
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| 131 | bool operator==(const MCRegister &Other) const { return Reg == Other.id(); } |
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| 132 | bool operator!=(const MCRegister &Other) const { return Reg != Other.id(); } |
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| 133 | |||
| 134 | /// Comparisons against register constants. E.g. |
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| 135 | /// * R == AArch64::WZR |
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| 136 | /// * R == 0 |
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| 137 | /// * R == VirtRegMap::NO_PHYS_REG |
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| 138 | bool operator==(unsigned Other) const { return Reg == Other; } |
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| 139 | bool operator!=(unsigned Other) const { return Reg != Other; } |
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| 140 | bool operator==(int Other) const { return Reg == unsigned(Other); } |
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| 141 | bool operator!=(int Other) const { return Reg != unsigned(Other); } |
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| 142 | // MSVC requires that we explicitly declare these two as well. |
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| 143 | bool operator==(MCPhysReg Other) const { return Reg == unsigned(Other); } |
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| 144 | bool operator!=(MCPhysReg Other) const { return Reg != unsigned(Other); } |
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| 145 | }; |
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| 146 | |||
| 147 | // Provide DenseMapInfo for Register |
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| 148 | template<> struct DenseMapInfo<Register> { |
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| 149 | static inline unsigned getEmptyKey() { |
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| 150 | return DenseMapInfo<unsigned>::getEmptyKey(); |
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| 151 | } |
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| 152 | static inline unsigned getTombstoneKey() { |
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| 153 | return DenseMapInfo<unsigned>::getTombstoneKey(); |
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| 154 | } |
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| 155 | static unsigned getHashValue(const Register &Val) { |
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| 156 | return DenseMapInfo<unsigned>::getHashValue(Val.id()); |
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| 157 | } |
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| 158 | static bool isEqual(const Register &LHS, const Register &RHS) { |
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| 159 | return DenseMapInfo<unsigned>::isEqual(LHS.id(), RHS.id()); |
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| 160 | } |
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| 161 | }; |
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| 162 | |||
| 163 | } |
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| 164 | |||
| 165 | #endif // LLVM_CODEGEN_REGISTER_H |