MCRegisterInfo.h revision 8ca9a862038e8c4e9a2ca73b3b75e1be3425155f
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/ADT/DenseSet.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; 30private: 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 DenseSet<unsigned> RegSet; 38public: 39 MCRegisterClass(unsigned id, const char *name, 40 unsigned RS, unsigned Al, int CC, bool Allocable, 41 iterator RB, iterator RE) 42 : ID(id), Name(name), RegSize(RS), Alignment(Al), CopyCost(CC), 43 Allocatable(Allocable), RegsBegin(RB), RegsEnd(RE) {} 44 45 /// initMCRegisterClass - Initialize initMCRegisterClass. *DO NOT USE*. 46 // FIXME: This could go away if RegSet would use a constant bit field. 47 void initMCRegisterClass() { 48 RegSet.resize(getNumRegs()); 49 for (iterator I = RegsBegin, E = RegsEnd; I != E; ++I) 50 RegSet.insert(*I); 51 } 52 53 /// getID() - Return the register class ID number. 54 /// 55 unsigned getID() const { return ID; } 56 57 /// getName() - Return the register class name for debugging. 58 /// 59 const char *getName() const { return Name; } 60 61 /// begin/end - Return all of the registers in this class. 62 /// 63 iterator begin() const { return RegsBegin; } 64 iterator end() const { return RegsEnd; } 65 66 /// getNumRegs - Return the number of registers in this class. 67 /// 68 unsigned getNumRegs() const { return (unsigned)(RegsEnd-RegsBegin); } 69 70 /// getRegister - Return the specified register in the class. 71 /// 72 unsigned getRegister(unsigned i) const { 73 assert(i < getNumRegs() && "Register number out of range!"); 74 return RegsBegin[i]; 75 } 76 77 /// contains - Return true if the specified register is included in this 78 /// register class. This does not include virtual registers. 79 bool contains(unsigned Reg) const { 80 return RegSet.count(Reg); 81 } 82 83 /// contains - Return true if both registers are in this class. 84 bool contains(unsigned Reg1, unsigned Reg2) const { 85 return contains(Reg1) && contains(Reg2); 86 } 87 88 /// getSize - Return the size of the register in bytes, which is also the size 89 /// of a stack slot allocated to hold a spilled copy of this register. 90 unsigned getSize() const { return RegSize; } 91 92 /// getAlignment - Return the minimum required alignment for a register of 93 /// this class. 94 unsigned getAlignment() const { return Alignment; } 95 96 /// getCopyCost - Return the cost of copying a value between two registers in 97 /// this class. A negative number means the register class is very expensive 98 /// to copy e.g. status flag register classes. 99 int getCopyCost() const { return CopyCost; } 100 101 /// isAllocatable - Return true if this register class may be used to create 102 /// virtual registers. 103 bool isAllocatable() const { return Allocatable; } 104}; 105 106/// MCRegisterDesc - This record contains all of the information known about 107/// a particular register. The Overlaps field contains a pointer to a zero 108/// terminated array of registers that this register aliases, starting with 109/// itself. This is needed for architectures like X86 which have AL alias AX 110/// alias EAX. The SubRegs field is a zero terminated array of registers that 111/// are sub-registers of the specific register, e.g. AL, AH are sub-registers of 112/// AX. The SuperRegs field is a zero terminated array of registers that are 113/// super-registers of the specific register, e.g. RAX, EAX, are super-registers 114/// of AX. 115/// 116struct MCRegisterDesc { 117 const char *Name; // Printable name for the reg (for debugging) 118 const unsigned *Overlaps; // Overlapping registers, described above 119 const unsigned *SubRegs; // Sub-register set, described above 120 const unsigned *SuperRegs; // Super-register set, described above 121}; 122 123/// MCRegisterInfo base class - We assume that the target defines a static 124/// array of MCRegisterDesc objects that represent all of the machine 125/// registers that the target has. As such, we simply have to track a pointer 126/// to this array so that we can turn register number into a register 127/// descriptor. 128/// 129/// Note this class is designed to be a base class of TargetRegisterInfo, which 130/// is the interface used by codegen. However, specific targets *should never* 131/// specialize this class. MCRegisterInfo should only contain getters to access 132/// TableGen generated physical register data. It must not be extended with 133/// virtual methods. 134/// 135class MCRegisterInfo { 136public: 137 typedef const MCRegisterClass *regclass_iterator; 138private: 139 const MCRegisterDesc *Desc; // Pointer to the descriptor array 140 unsigned NumRegs; // Number of entries in the array 141 unsigned RAReg; // Return address register 142 const MCRegisterClass *Classes; // Pointer to the regclass array 143 unsigned NumClasses; // Number of entries in the array 144 DenseMap<unsigned, int> L2DwarfRegs; // LLVM to Dwarf regs mapping 145 DenseMap<unsigned, int> EHL2DwarfRegs; // LLVM to Dwarf regs mapping EH 146 DenseMap<unsigned, unsigned> Dwarf2LRegs; // Dwarf to LLVM regs mapping 147 DenseMap<unsigned, unsigned> EHDwarf2LRegs; // Dwarf to LLVM regs mapping EH 148 DenseMap<unsigned, int> L2SEHRegs; // LLVM to SEH regs mapping 149 150public: 151 /// InitMCRegisterInfo - Initialize MCRegisterInfo, called by TableGen 152 /// auto-generated routines. *DO NOT USE*. 153 void InitMCRegisterInfo(const MCRegisterDesc *D, unsigned NR, unsigned RA, 154 MCRegisterClass *C, unsigned NC) { 155 Desc = D; 156 NumRegs = NR; 157 RAReg = RA; 158 Classes = C; 159 NumClasses = NC; 160 // FIXME: This should go away. 161 for (unsigned i = 0; i != NC; ++i) 162 C[i].initMCRegisterClass(); 163 } 164 165 /// mapLLVMRegToDwarfReg - Used to initialize LLVM register to Dwarf 166 /// register number mapping. Called by TableGen auto-generated routines. 167 /// *DO NOT USE*. 168 void mapLLVMRegToDwarfReg(unsigned LLVMReg, int DwarfReg, bool isEH) { 169 if (isEH) 170 EHL2DwarfRegs[LLVMReg] = DwarfReg; 171 else 172 L2DwarfRegs[LLVMReg] = DwarfReg; 173 } 174 175 /// mapDwarfRegToLLVMReg - Used to initialize Dwarf register to LLVM 176 /// register number mapping. Called by TableGen auto-generated routines. 177 /// *DO NOT USE*. 178 void mapDwarfRegToLLVMReg(unsigned DwarfReg, unsigned LLVMReg, bool isEH) { 179 if (isEH) 180 EHDwarf2LRegs[DwarfReg] = LLVMReg; 181 else 182 Dwarf2LRegs[DwarfReg] = LLVMReg; 183 } 184 185 /// mapLLVMRegToSEHReg - Used to initialize LLVM register to SEH register 186 /// number mapping. By default the SEH register number is just the same 187 /// as the LLVM register number. 188 /// FIXME: TableGen these numbers. Currently this requires target specific 189 /// initialization code. 190 void mapLLVMRegToSEHReg(unsigned LLVMReg, int SEHReg) { 191 L2SEHRegs[LLVMReg] = SEHReg; 192 } 193 194 /// getRARegister - This method should return the register where the return 195 /// address can be found. 196 unsigned getRARegister() const { 197 return RAReg; 198 } 199 200 const MCRegisterDesc &operator[](unsigned RegNo) const { 201 assert(RegNo < NumRegs && 202 "Attempting to access record for invalid register number!"); 203 return Desc[RegNo]; 204 } 205 206 /// Provide a get method, equivalent to [], but more useful if we have a 207 /// pointer to this object. 208 /// 209 const MCRegisterDesc &get(unsigned RegNo) const { 210 return operator[](RegNo); 211 } 212 213 /// getAliasSet - Return the set of registers aliased by the specified 214 /// register, or a null list of there are none. The list returned is zero 215 /// terminated. 216 /// 217 const unsigned *getAliasSet(unsigned RegNo) const { 218 // The Overlaps set always begins with Reg itself. 219 return get(RegNo).Overlaps + 1; 220 } 221 222 /// getOverlaps - Return a list of registers that overlap Reg, including 223 /// itself. This is the same as the alias set except Reg is included in the 224 /// list. 225 /// These are exactly the registers in { x | regsOverlap(x, Reg) }. 226 /// 227 const unsigned *getOverlaps(unsigned RegNo) const { 228 return get(RegNo).Overlaps; 229 } 230 231 /// getSubRegisters - Return the list of registers that are sub-registers of 232 /// the specified register, or a null list of there are none. The list 233 /// returned is zero terminated and sorted according to super-sub register 234 /// relations. e.g. X86::RAX's sub-register list is EAX, AX, AL, AH. 235 /// 236 const unsigned *getSubRegisters(unsigned RegNo) const { 237 return get(RegNo).SubRegs; 238 } 239 240 /// getSuperRegisters - Return the list of registers that are super-registers 241 /// of the specified register, or a null list of there are none. The list 242 /// returned is zero terminated and sorted according to super-sub register 243 /// relations. e.g. X86::AL's super-register list is AX, EAX, RAX. 244 /// 245 const unsigned *getSuperRegisters(unsigned RegNo) const { 246 return get(RegNo).SuperRegs; 247 } 248 249 /// getName - Return the human-readable symbolic target-specific name for the 250 /// specified physical register. 251 const char *getName(unsigned RegNo) const { 252 return get(RegNo).Name; 253 } 254 255 /// getNumRegs - Return the number of registers this target has (useful for 256 /// sizing arrays holding per register information) 257 unsigned getNumRegs() const { 258 return NumRegs; 259 } 260 261 /// getDwarfRegNum - Map a target register to an equivalent dwarf register 262 /// number. Returns -1 if there is no equivalent value. The second 263 /// parameter allows targets to use different numberings for EH info and 264 /// debugging info. 265 int getDwarfRegNum(unsigned RegNum, bool isEH) const { 266 const DenseMap<unsigned, int> &M = isEH ? EHL2DwarfRegs : L2DwarfRegs; 267 const DenseMap<unsigned, int>::const_iterator I = M.find(RegNum); 268 if (I == M.end()) return -1; 269 return I->second; 270 } 271 272 /// getLLVMRegNum - Map a dwarf register back to a target register. 273 /// 274 int getLLVMRegNum(unsigned RegNum, bool isEH) const { 275 const DenseMap<unsigned, unsigned> &M = isEH ? EHDwarf2LRegs : Dwarf2LRegs; 276 const DenseMap<unsigned, unsigned>::const_iterator I = M.find(RegNum); 277 if (I == M.end()) { 278 assert(0 && "Invalid RegNum"); 279 return -1; 280 } 281 return I->second; 282 } 283 284 /// getSEHRegNum - Map a target register to an equivalent SEH register 285 /// number. Returns LLVM register number if there is no equivalent value. 286 int getSEHRegNum(unsigned RegNum) const { 287 const DenseMap<unsigned, int>::const_iterator I = L2SEHRegs.find(RegNum); 288 if (I == L2SEHRegs.end()) return (int)RegNum; 289 return I->second; 290 } 291 292 regclass_iterator regclass_begin() const { return Classes; } 293 regclass_iterator regclass_end() const { return Classes+NumClasses; } 294 295 unsigned getNumRegClasses() const { 296 return (unsigned)(regclass_end()-regclass_begin()); 297 } 298 299 /// getRegClass - Returns the register class associated with the enumeration 300 /// value. See class MCOperandInfo. 301 const MCRegisterClass getRegClass(unsigned i) const { 302 assert(i < getNumRegClasses() && "Register Class ID out of range"); 303 return Classes[i]; 304 } 305}; 306 307} // End llvm namespace 308 309#endif 310