1 //===- llvm/CodeGen/VirtRegMap.h - Virtual Register Map ---------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements a virtual register map. This maps virtual registers to 11 // physical registers and virtual registers to stack slots. It is created and 12 // updated by a register allocator and then used by a machine code rewriter that 13 // adds spill code and rewrites virtual into physical register references. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #ifndef LLVM_CODEGEN_VIRTREGMAP_H 18 #define LLVM_CODEGEN_VIRTREGMAP_H 19 20 #include "llvm/ADT/IndexedMap.h" 21 #include "llvm/CodeGen/MachineFunctionPass.h" 22 #include "llvm/MC/MCRegisterInfo.h" 23 #include "llvm/Pass.h" 24 #include "llvm/Target/TargetRegisterInfo.h" 25 #include <cassert> 26 27 namespace llvm { 28 29 class MachineFunction; 30 class MachineRegisterInfo; 31 class raw_ostream; 32 class TargetInstrInfo; 33 34 class VirtRegMap : public MachineFunctionPass { 35 public: 36 enum { 37 NO_PHYS_REG = 0, 38 NO_STACK_SLOT = (1L << 30)-1, 39 MAX_STACK_SLOT = (1L << 18)-1 40 }; 41 42 private: 43 MachineRegisterInfo *MRI; 44 const TargetInstrInfo *TII; 45 const TargetRegisterInfo *TRI; 46 MachineFunction *MF; 47 48 /// Virt2PhysMap - This is a virtual to physical register 49 /// mapping. Each virtual register is required to have an entry in 50 /// it; even spilled virtual registers (the register mapped to a 51 /// spilled register is the temporary used to load it from the 52 /// stack). 53 IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2PhysMap; 54 55 /// Virt2StackSlotMap - This is virtual register to stack slot 56 /// mapping. Each spilled virtual register has an entry in it 57 /// which corresponds to the stack slot this register is spilled 58 /// at. 59 IndexedMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap; 60 61 /// Virt2SplitMap - This is virtual register to splitted virtual register 62 /// mapping. 63 IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2SplitMap; 64 65 /// createSpillSlot - Allocate a spill slot for RC from MFI. 66 unsigned createSpillSlot(const TargetRegisterClass *RC); 67 68 public: 69 static char ID; 70 71 VirtRegMap() : MachineFunctionPass(ID), Virt2PhysMap(NO_PHYS_REG), 72 Virt2StackSlotMap(NO_STACK_SLOT), Virt2SplitMap(0) {} 73 VirtRegMap(const VirtRegMap &) = delete; 74 VirtRegMap &operator=(const VirtRegMap &) = delete; 75 76 bool runOnMachineFunction(MachineFunction &MF) override; 77 78 void getAnalysisUsage(AnalysisUsage &AU) const override { 79 AU.setPreservesAll(); 80 MachineFunctionPass::getAnalysisUsage(AU); 81 } 82 83 MachineFunction &getMachineFunction() const { 84 assert(MF && "getMachineFunction called before runOnMachineFunction"); 85 return *MF; 86 } 87 88 MachineRegisterInfo &getRegInfo() const { return *MRI; } 89 const TargetRegisterInfo &getTargetRegInfo() const { return *TRI; } 90 91 void grow(); 92 93 /// @brief returns true if the specified virtual register is 94 /// mapped to a physical register 95 bool hasPhys(unsigned virtReg) const { 96 return getPhys(virtReg) != NO_PHYS_REG; 97 } 98 99 /// @brief returns the physical register mapped to the specified 100 /// virtual register 101 unsigned getPhys(unsigned virtReg) const { 102 assert(TargetRegisterInfo::isVirtualRegister(virtReg)); 103 return Virt2PhysMap[virtReg]; 104 } 105 106 /// @brief creates a mapping for the specified virtual register to 107 /// the specified physical register 108 void assignVirt2Phys(unsigned virtReg, MCPhysReg physReg); 109 110 /// @brief clears the specified virtual register's, physical 111 /// register mapping 112 void clearVirt(unsigned virtReg) { 113 assert(TargetRegisterInfo::isVirtualRegister(virtReg)); 114 assert(Virt2PhysMap[virtReg] != NO_PHYS_REG && 115 "attempt to clear a not assigned virtual register"); 116 Virt2PhysMap[virtReg] = NO_PHYS_REG; 117 } 118 119 /// @brief clears all virtual to physical register mappings 120 void clearAllVirt() { 121 Virt2PhysMap.clear(); 122 grow(); 123 } 124 125 /// @brief returns true if VirtReg is assigned to its preferred physreg. 126 bool hasPreferredPhys(unsigned VirtReg); 127 128 /// @brief returns true if VirtReg has a known preferred register. 129 /// This returns false if VirtReg has a preference that is a virtual 130 /// register that hasn't been assigned yet. 131 bool hasKnownPreference(unsigned VirtReg); 132 133 /// @brief records virtReg is a split live interval from SReg. 134 void setIsSplitFromReg(unsigned virtReg, unsigned SReg) { 135 Virt2SplitMap[virtReg] = SReg; 136 } 137 138 /// @brief returns the live interval virtReg is split from. 139 unsigned getPreSplitReg(unsigned virtReg) const { 140 return Virt2SplitMap[virtReg]; 141 } 142 143 /// getOriginal - Return the original virtual register that VirtReg descends 144 /// from through splitting. 145 /// A register that was not created by splitting is its own original. 146 /// This operation is idempotent. 147 unsigned getOriginal(unsigned VirtReg) const { 148 unsigned Orig = getPreSplitReg(VirtReg); 149 return Orig ? Orig : VirtReg; 150 } 151 152 /// @brief returns true if the specified virtual register is not 153 /// mapped to a stack slot or rematerialized. 154 bool isAssignedReg(unsigned virtReg) const { 155 if (getStackSlot(virtReg) == NO_STACK_SLOT) 156 return true; 157 // Split register can be assigned a physical register as well as a 158 // stack slot or remat id. 159 return (Virt2SplitMap[virtReg] && Virt2PhysMap[virtReg] != NO_PHYS_REG); 160 } 161 162 /// @brief returns the stack slot mapped to the specified virtual 163 /// register 164 int getStackSlot(unsigned virtReg) const { 165 assert(TargetRegisterInfo::isVirtualRegister(virtReg)); 166 return Virt2StackSlotMap[virtReg]; 167 } 168 169 /// @brief create a mapping for the specifed virtual register to 170 /// the next available stack slot 171 int assignVirt2StackSlot(unsigned virtReg); 172 173 /// @brief create a mapping for the specified virtual register to 174 /// the specified stack slot 175 void assignVirt2StackSlot(unsigned virtReg, int frameIndex); 176 177 void print(raw_ostream &OS, const Module* M = nullptr) const override; 178 void dump() const; 179 }; 180 181 inline raw_ostream &operator<<(raw_ostream &OS, const VirtRegMap &VRM) { 182 VRM.print(OS); 183 return OS; 184 } 185 186 } // end llvm namespace 187 188 #endif // LLVM_CODEGEN_VIRTREGMAP_H 189
