MCRegisterInfo.h revision 90a468c424f7d0a85b3dc783634106d9a46d6688
1//=== MC/MCRegisterInfo.h - Target Register Description ---------*- 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 describes an abstract interface used to get information about a 11// target machines register file. This information is used for a variety of 12// purposed, especially register allocation. 13// 14//===----------------------------------------------------------------------===// 15 16#ifndef LLVM_MC_MCREGISTERINFO_H 17#define LLVM_MC_MCREGISTERINFO_H 18 19#include "llvm/ADT/DenseMap.h" 20#include "llvm/Support/ErrorHandling.h" 21#include <cassert> 22 23namespace llvm { 24 25/// MCRegisterClass - Base class of TargetRegisterClass. 26class MCRegisterClass { 27public: 28 typedef const unsigned* iterator; 29 typedef const unsigned* const_iterator; 30 31 unsigned ID; 32 const char *Name; 33 const unsigned RegSize, Alignment; // Size & Alignment of register in bytes 34 const int CopyCost; 35 const bool Allocatable; 36 const iterator RegsBegin, RegsEnd; 37 const unsigned char *const RegSet; 38 const unsigned RegSetSize; 39 40 /// getID() - Return the register class ID number. 41 /// 42 unsigned getID() const { return ID; } 43 44 /// getName() - Return the register class name for debugging. 45 /// 46 const char *getName() const { return Name; } 47 48 /// begin/end - Return all of the registers in this class. 49 /// 50 iterator begin() const { return RegsBegin; } 51 iterator end() const { return RegsEnd; } 52 53 /// getNumRegs - Return the number of registers in this class. 54 /// 55 unsigned getNumRegs() const { return (unsigned)(RegsEnd-RegsBegin); } 56 57 /// getRegister - Return the specified register in the class. 58 /// 59 unsigned getRegister(unsigned i) const { 60 assert(i < getNumRegs() && "Register number out of range!"); 61 return RegsBegin[i]; 62 } 63 64 /// contains - Return true if the specified register is included in this 65 /// register class. This does not include virtual registers. 66 bool contains(unsigned Reg) const { 67 unsigned InByte = Reg % 8; 68 unsigned Byte = Reg / 8; 69 if (Byte >= RegSetSize) 70 return false; 71 return (RegSet[Byte] & (1 << InByte)) != 0; 72 } 73 74 /// contains - Return true if both registers are in this class. 75 bool contains(unsigned Reg1, unsigned Reg2) const { 76 return contains(Reg1) && contains(Reg2); 77 } 78 79 /// getSize - Return the size of the register in bytes, which is also the size 80 /// of a stack slot allocated to hold a spilled copy of this register. 81 unsigned getSize() const { return RegSize; } 82 83 /// getAlignment - Return the minimum required alignment for a register of 84 /// this class. 85 unsigned getAlignment() const { return Alignment; } 86 87 /// getCopyCost - Return the cost of copying a value between two registers in 88 /// this class. A negative number means the register class is very expensive 89 /// to copy e.g. status flag register classes. 90 int getCopyCost() const { return CopyCost; } 91 92 /// isAllocatable - Return true if this register class may be used to create 93 /// virtual registers. 94 bool isAllocatable() const { return Allocatable; } 95}; 96 97/// MCRegisterDesc - This record contains all of the information known about 98/// a particular register. The Overlaps field contains a pointer to a zero 99/// terminated array of registers that this register aliases, starting with 100/// itself. This is needed for architectures like X86 which have AL alias AX 101/// alias EAX. The SubRegs field is a zero terminated array of registers that 102/// are sub-registers of the specific register, e.g. AL, AH are sub-registers of 103/// AX. The SuperRegs field is a zero terminated array of registers that are 104/// super-registers of the specific register, e.g. RAX, EAX, are super-registers 105/// of AX. 106/// 107struct MCRegisterDesc { 108 const char *Name; // Printable name for the reg (for debugging) 109 const unsigned *Overlaps; // Overlapping registers, described above 110 const unsigned *SubRegs; // Sub-register set, described above 111 const unsigned *SuperRegs; // Super-register set, described above 112}; 113 114/// MCRegisterInfo base class - We assume that the target defines a static 115/// array of MCRegisterDesc objects that represent all of the machine 116/// registers that the target has. As such, we simply have to track a pointer 117/// to this array so that we can turn register number into a register 118/// descriptor. 119/// 120/// Note this class is designed to be a base class of TargetRegisterInfo, which 121/// is the interface used by codegen. However, specific targets *should never* 122/// specialize this class. MCRegisterInfo should only contain getters to access 123/// TableGen generated physical register data. It must not be extended with 124/// virtual methods. 125/// 126class MCRegisterInfo { 127public: 128 typedef const MCRegisterClass *regclass_iterator; 129private: 130 const MCRegisterDesc *Desc; // Pointer to the descriptor array 131 unsigned NumRegs; // Number of entries in the array 132 unsigned RAReg; // Return address register 133 const MCRegisterClass *Classes; // Pointer to the regclass array 134 unsigned NumClasses; // Number of entries in the array 135 DenseMap<unsigned, int> L2DwarfRegs; // LLVM to Dwarf regs mapping 136 DenseMap<unsigned, int> EHL2DwarfRegs; // LLVM to Dwarf regs mapping EH 137 DenseMap<unsigned, unsigned> Dwarf2LRegs; // Dwarf to LLVM regs mapping 138 DenseMap<unsigned, unsigned> EHDwarf2LRegs; // Dwarf to LLVM regs mapping EH 139 DenseMap<unsigned, int> L2SEHRegs; // LLVM to SEH regs mapping 140 141public: 142 /// InitMCRegisterInfo - Initialize MCRegisterInfo, called by TableGen 143 /// auto-generated routines. *DO NOT USE*. 144 void InitMCRegisterInfo(const MCRegisterDesc *D, unsigned NR, unsigned RA, 145 const MCRegisterClass *C, unsigned NC) { 146 Desc = D; 147 NumRegs = NR; 148 RAReg = RA; 149 Classes = C; 150 NumClasses = NC; 151 } 152 153 /// mapLLVMRegToDwarfReg - Used to initialize LLVM register to Dwarf 154 /// register number mapping. Called by TableGen auto-generated routines. 155 /// *DO NOT USE*. 156 void mapLLVMRegToDwarfReg(unsigned LLVMReg, int DwarfReg, bool isEH) { 157 if (isEH) 158 EHL2DwarfRegs[LLVMReg] = DwarfReg; 159 else 160 L2DwarfRegs[LLVMReg] = DwarfReg; 161 } 162 163 /// mapDwarfRegToLLVMReg - Used to initialize Dwarf register to LLVM 164 /// register number mapping. Called by TableGen auto-generated routines. 165 /// *DO NOT USE*. 166 void mapDwarfRegToLLVMReg(unsigned DwarfReg, unsigned LLVMReg, bool isEH) { 167 if (isEH) 168 EHDwarf2LRegs[DwarfReg] = LLVMReg; 169 else 170 Dwarf2LRegs[DwarfReg] = LLVMReg; 171 } 172 173 /// mapLLVMRegToSEHReg - Used to initialize LLVM register to SEH register 174 /// number mapping. By default the SEH register number is just the same 175 /// as the LLVM register number. 176 /// FIXME: TableGen these numbers. Currently this requires target specific 177 /// initialization code. 178 void mapLLVMRegToSEHReg(unsigned LLVMReg, int SEHReg) { 179 L2SEHRegs[LLVMReg] = SEHReg; 180 } 181 182 /// getRARegister - This method should return the register where the return 183 /// address can be found. 184 unsigned getRARegister() const { 185 return RAReg; 186 } 187 188 const MCRegisterDesc &operator[](unsigned RegNo) const { 189 assert(RegNo < NumRegs && 190 "Attempting to access record for invalid register number!"); 191 return Desc[RegNo]; 192 } 193 194 /// Provide a get method, equivalent to [], but more useful if we have a 195 /// pointer to this object. 196 /// 197 const MCRegisterDesc &get(unsigned RegNo) const { 198 return operator[](RegNo); 199 } 200 201 /// getAliasSet - Return the set of registers aliased by the specified 202 /// register, or a null list of there are none. The list returned is zero 203 /// terminated. 204 /// 205 const unsigned *getAliasSet(unsigned RegNo) const { 206 // The Overlaps set always begins with Reg itself. 207 return get(RegNo).Overlaps + 1; 208 } 209 210 /// getOverlaps - Return a list of registers that overlap Reg, including 211 /// itself. This is the same as the alias set except Reg is included in the 212 /// list. 213 /// These are exactly the registers in { x | regsOverlap(x, Reg) }. 214 /// 215 const unsigned *getOverlaps(unsigned RegNo) const { 216 return get(RegNo).Overlaps; 217 } 218 219 /// getSubRegisters - Return the list of registers that are sub-registers of 220 /// the specified register, or a null list of there are none. The list 221 /// returned is zero terminated and sorted according to super-sub register 222 /// relations. e.g. X86::RAX's sub-register list is EAX, AX, AL, AH. 223 /// 224 const unsigned *getSubRegisters(unsigned RegNo) const { 225 return get(RegNo).SubRegs; 226 } 227 228 /// getSuperRegisters - Return the list of registers that are super-registers 229 /// of the specified register, or a null list of there are none. The list 230 /// returned is zero terminated and sorted according to super-sub register 231 /// relations. e.g. X86::AL's super-register list is AX, EAX, RAX. 232 /// 233 const unsigned *getSuperRegisters(unsigned RegNo) const { 234 return get(RegNo).SuperRegs; 235 } 236 237 /// getName - Return the human-readable symbolic target-specific name for the 238 /// specified physical register. 239 const char *getName(unsigned RegNo) const { 240 return get(RegNo).Name; 241 } 242 243 /// getNumRegs - Return the number of registers this target has (useful for 244 /// sizing arrays holding per register information) 245 unsigned getNumRegs() const { 246 return NumRegs; 247 } 248 249 /// getDwarfRegNum - Map a target register to an equivalent dwarf register 250 /// number. Returns -1 if there is no equivalent value. The second 251 /// parameter allows targets to use different numberings for EH info and 252 /// debugging info. 253 int getDwarfRegNum(unsigned RegNum, bool isEH) const { 254 const DenseMap<unsigned, int> &M = isEH ? EHL2DwarfRegs : L2DwarfRegs; 255 const DenseMap<unsigned, int>::const_iterator I = M.find(RegNum); 256 if (I == M.end()) return -1; 257 return I->second; 258 } 259 260 /// getLLVMRegNum - Map a dwarf register back to a target register. 261 /// 262 int getLLVMRegNum(unsigned RegNum, bool isEH) const { 263 const DenseMap<unsigned, unsigned> &M = isEH ? EHDwarf2LRegs : Dwarf2LRegs; 264 const DenseMap<unsigned, unsigned>::const_iterator I = M.find(RegNum); 265 if (I == M.end()) { 266 llvm_unreachable("Invalid RegNum"); 267 } 268 return I->second; 269 } 270 271 /// getSEHRegNum - Map a target register to an equivalent SEH register 272 /// number. Returns LLVM register number if there is no equivalent value. 273 int getSEHRegNum(unsigned RegNum) const { 274 const DenseMap<unsigned, int>::const_iterator I = L2SEHRegs.find(RegNum); 275 if (I == L2SEHRegs.end()) return (int)RegNum; 276 return I->second; 277 } 278 279 regclass_iterator regclass_begin() const { return Classes; } 280 regclass_iterator regclass_end() const { return Classes+NumClasses; } 281 282 unsigned getNumRegClasses() const { 283 return (unsigned)(regclass_end()-regclass_begin()); 284 } 285 286 /// getRegClass - Returns the register class associated with the enumeration 287 /// value. See class MCOperandInfo. 288 const MCRegisterClass getRegClass(unsigned i) const { 289 assert(i < getNumRegClasses() && "Register Class ID out of range"); 290 return Classes[i]; 291 } 292}; 293 294} // End llvm namespace 295 296#endif 297