1 //===- MC/MCRegisterInfo.h - Target Register Description --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_MC_MCREGISTERINFO_H
17 #define LLVM_MC_MCREGISTERINFO_H
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/iterator_range.h"
21 #include "llvm/MC/LaneBitmask.h"
28 /// An unsigned integer type large enough to represent all physical registers,
29 /// but not necessarily virtual registers.
30 using MCPhysReg = uint16_t;
32 /// MCRegisterClass - Base class of TargetRegisterClass.
33 class MCRegisterClass {
35 using iterator = const MCPhysReg*;
36 using const_iterator = const MCPhysReg*;
38 const iterator RegsBegin;
39 const uint8_t *const RegSet;
40 const uint32_t NameIdx;
41 const uint16_t RegsSize;
42 const uint16_t RegSetSize;
44 const uint16_t PhysRegSize;
45 const int8_t CopyCost;
46 const bool Allocatable;
48 /// getID() - Return the register class ID number.
50 unsigned getID() const { return ID; }
52 /// begin/end - Return all of the registers in this class.
54 iterator begin() const { return RegsBegin; }
55 iterator end() const { return RegsBegin + RegsSize; }
57 /// getNumRegs - Return the number of registers in this class.
59 unsigned getNumRegs() const { return RegsSize; }
61 /// getRegister - Return the specified register in the class.
63 unsigned getRegister(unsigned i) const {
64 assert(i < getNumRegs() && "Register number out of range!");
68 /// contains - Return true if the specified register is included in this
69 /// register class. This does not include virtual registers.
70 bool contains(unsigned Reg) const {
71 unsigned InByte = Reg % 8;
72 unsigned Byte = Reg / 8;
73 if (Byte >= RegSetSize)
75 return (RegSet[Byte] & (1 << InByte)) != 0;
78 /// contains - Return true if both registers are in this class.
79 bool contains(unsigned Reg1, unsigned Reg2) const {
80 return contains(Reg1) && contains(Reg2);
83 /// Return the size of the physical register in bytes.
84 unsigned getPhysRegSize() const { return PhysRegSize; }
85 /// Temporary function to allow out-of-tree targets to switch.
86 unsigned getSize() const { return getPhysRegSize(); }
88 /// getCopyCost - Return the cost of copying a value between two registers in
89 /// this class. A negative number means the register class is very expensive
90 /// to copy e.g. status flag register classes.
91 int getCopyCost() const { return CopyCost; }
93 /// isAllocatable - Return true if this register class may be used to create
94 /// virtual registers.
95 bool isAllocatable() const { return Allocatable; }
98 /// MCRegisterDesc - This record contains information about a particular
99 /// register. The SubRegs field is a zero terminated array of registers that
100 /// are sub-registers of the specific register, e.g. AL, AH are sub-registers
101 /// of AX. The SuperRegs field is a zero terminated array of registers that are
102 /// super-registers of the specific register, e.g. RAX, EAX, are
103 /// super-registers of AX.
105 struct MCRegisterDesc {
106 uint32_t Name; // Printable name for the reg (for debugging)
107 uint32_t SubRegs; // Sub-register set, described above
108 uint32_t SuperRegs; // Super-register set, described above
110 // Offset into MCRI::SubRegIndices of a list of sub-register indices for each
111 // sub-register in SubRegs.
112 uint32_t SubRegIndices;
114 // RegUnits - Points to the list of register units. The low 4 bits holds the
115 // Scale, the high bits hold an offset into DiffLists. See MCRegUnitIterator.
118 /// Index into list with lane mask sequences. The sequence contains a lanemask
119 /// for every register unit.
120 uint16_t RegUnitLaneMasks;
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
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
135 class MCRegisterInfo {
137 using regclass_iterator = const MCRegisterClass *;
139 /// DwarfLLVMRegPair - Emitted by tablegen so Dwarf<->LLVM reg mappings can be
140 /// performed with a binary search.
141 struct DwarfLLVMRegPair {
145 bool operator<(DwarfLLVMRegPair RHS) const { return FromReg < RHS.FromReg; }
148 /// SubRegCoveredBits - Emitted by tablegen: bit range covered by a subreg
149 /// index, -1 in any being invalid.
150 struct SubRegCoveredBits {
156 const MCRegisterDesc *Desc; // Pointer to the descriptor array
157 unsigned NumRegs; // Number of entries in the array
158 unsigned RAReg; // Return address register
159 unsigned PCReg; // Program counter register
160 const MCRegisterClass *Classes; // Pointer to the regclass array
161 unsigned NumClasses; // Number of entries in the array
162 unsigned NumRegUnits; // Number of regunits.
163 const MCPhysReg (*RegUnitRoots)[2]; // Pointer to regunit root table.
164 const MCPhysReg *DiffLists; // Pointer to the difflists array
165 const LaneBitmask *RegUnitMaskSequences; // Pointer to lane mask sequences
166 // for register units.
167 const char *RegStrings; // Pointer to the string table.
168 const char *RegClassStrings; // Pointer to the class strings.
169 const uint16_t *SubRegIndices; // Pointer to the subreg lookup
171 const SubRegCoveredBits *SubRegIdxRanges; // Pointer to the subreg covered
173 unsigned NumSubRegIndices; // Number of subreg indices.
174 const uint16_t *RegEncodingTable; // Pointer to array of register
177 unsigned L2DwarfRegsSize;
178 unsigned EHL2DwarfRegsSize;
179 unsigned Dwarf2LRegsSize;
180 unsigned EHDwarf2LRegsSize;
181 const DwarfLLVMRegPair *L2DwarfRegs; // LLVM to Dwarf regs mapping
182 const DwarfLLVMRegPair *EHL2DwarfRegs; // LLVM to Dwarf regs mapping EH
183 const DwarfLLVMRegPair *Dwarf2LRegs; // Dwarf to LLVM regs mapping
184 const DwarfLLVMRegPair *EHDwarf2LRegs; // Dwarf to LLVM regs mapping EH
185 DenseMap<unsigned, int> L2SEHRegs; // LLVM to SEH regs mapping
186 DenseMap<unsigned, int> L2CVRegs; // LLVM to CV regs mapping
189 /// DiffListIterator - Base iterator class that can traverse the
190 /// differentially encoded register and regunit lists in DiffLists.
191 /// Don't use this class directly, use one of the specialized sub-classes
193 class DiffListIterator {
195 const MCPhysReg *List = nullptr;
198 /// Create an invalid iterator. Call init() to point to something useful.
199 DiffListIterator() = default;
201 /// init - Point the iterator to InitVal, decoding subsequent values from
202 /// DiffList. The iterator will initially point to InitVal, sub-classes are
203 /// responsible for skipping the seed value if it is not part of the list.
204 void init(MCPhysReg InitVal, const MCPhysReg *DiffList) {
209 /// advance - Move to the next list position, return the applied
210 /// differential. This function does not detect the end of the list, that
211 /// is the caller's responsibility (by checking for a 0 return value).
213 assert(isValid() && "Cannot move off the end of the list.");
214 MCPhysReg D = *List++;
220 /// isValid - returns true if this iterator is not yet at the end.
221 bool isValid() const { return List; }
223 /// Dereference the iterator to get the value at the current position.
224 unsigned operator*() const { return Val; }
226 /// Pre-increment to move to the next position.
228 // The end of the list is encoded as a 0 differential.
234 // These iterators are allowed to sub-class DiffListIterator and access
235 // internal list pointers.
236 friend class MCSubRegIterator;
237 friend class MCSubRegIndexIterator;
238 friend class MCSuperRegIterator;
239 friend class MCRegUnitIterator;
240 friend class MCRegUnitMaskIterator;
241 friend class MCRegUnitRootIterator;
243 /// \brief Initialize MCRegisterInfo, called by TableGen
244 /// auto-generated routines. *DO NOT USE*.
245 void InitMCRegisterInfo(const MCRegisterDesc *D, unsigned NR, unsigned RA,
247 const MCRegisterClass *C, unsigned NC,
248 const MCPhysReg (*RURoots)[2],
251 const LaneBitmask *RUMS,
253 const char *ClassStrings,
254 const uint16_t *SubIndices,
256 const SubRegCoveredBits *SubIdxRanges,
257 const uint16_t *RET) {
264 RegUnitMaskSequences = RUMS;
265 RegStrings = Strings;
266 RegClassStrings = ClassStrings;
268 RegUnitRoots = RURoots;
270 SubRegIndices = SubIndices;
271 NumSubRegIndices = NumIndices;
272 SubRegIdxRanges = SubIdxRanges;
273 RegEncodingTable = RET;
275 // Initialize DWARF register mapping variables
276 EHL2DwarfRegs = nullptr;
277 EHL2DwarfRegsSize = 0;
278 L2DwarfRegs = nullptr;
280 EHDwarf2LRegs = nullptr;
281 EHDwarf2LRegsSize = 0;
282 Dwarf2LRegs = nullptr;
286 /// \brief Used to initialize LLVM register to Dwarf
287 /// register number mapping. Called by TableGen auto-generated routines.
289 void mapLLVMRegsToDwarfRegs(const DwarfLLVMRegPair *Map, unsigned Size,
293 EHL2DwarfRegsSize = Size;
296 L2DwarfRegsSize = Size;
300 /// \brief Used to initialize Dwarf register to LLVM
301 /// register number mapping. Called by TableGen auto-generated routines.
303 void mapDwarfRegsToLLVMRegs(const DwarfLLVMRegPair *Map, unsigned Size,
307 EHDwarf2LRegsSize = Size;
310 Dwarf2LRegsSize = Size;
314 /// mapLLVMRegToSEHReg - Used to initialize LLVM register to SEH register
315 /// number mapping. By default the SEH register number is just the same
316 /// as the LLVM register number.
317 /// FIXME: TableGen these numbers. Currently this requires target specific
318 /// initialization code.
319 void mapLLVMRegToSEHReg(unsigned LLVMReg, int SEHReg) {
320 L2SEHRegs[LLVMReg] = SEHReg;
323 void mapLLVMRegToCVReg(unsigned LLVMReg, int CVReg) {
324 L2CVRegs[LLVMReg] = CVReg;
327 /// \brief This method should return the register where the return
328 /// address can be found.
329 unsigned getRARegister() const {
333 /// Return the register which is the program counter.
334 unsigned getProgramCounter() const {
338 const MCRegisterDesc &operator[](unsigned RegNo) const {
339 assert(RegNo < NumRegs &&
340 "Attempting to access record for invalid register number!");
344 /// \brief Provide a get method, equivalent to [], but more useful with a
345 /// pointer to this object.
346 const MCRegisterDesc &get(unsigned RegNo) const {
347 return operator[](RegNo);
350 /// \brief Returns the physical register number of sub-register "Index"
351 /// for physical register RegNo. Return zero if the sub-register does not
353 unsigned getSubReg(unsigned Reg, unsigned Idx) const;
355 /// \brief Return a super-register of the specified register
356 /// Reg so its sub-register of index SubIdx is Reg.
357 unsigned getMatchingSuperReg(unsigned Reg, unsigned SubIdx,
358 const MCRegisterClass *RC) const;
360 /// \brief For a given register pair, return the sub-register index
361 /// if the second register is a sub-register of the first. Return zero
363 unsigned getSubRegIndex(unsigned RegNo, unsigned SubRegNo) const;
365 /// \brief Get the size of the bit range covered by a sub-register index.
366 /// If the index isn't continuous, return the sum of the sizes of its parts.
367 /// If the index is used to access subregisters of different sizes, return -1.
368 unsigned getSubRegIdxSize(unsigned Idx) const;
370 /// \brief Get the offset of the bit range covered by a sub-register index.
371 /// If an Offset doesn't make sense (the index isn't continuous, or is used to
372 /// access sub-registers at different offsets), return -1.
373 unsigned getSubRegIdxOffset(unsigned Idx) const;
375 /// \brief Return the human-readable symbolic target-specific name for the
376 /// specified physical register.
377 const char *getName(unsigned RegNo) const {
378 return RegStrings + get(RegNo).Name;
381 /// \brief Return the number of registers this target has (useful for
382 /// sizing arrays holding per register information)
383 unsigned getNumRegs() const {
387 /// \brief Return the number of sub-register indices
388 /// understood by the target. Index 0 is reserved for the no-op sub-register,
389 /// while 1 to getNumSubRegIndices() - 1 represent real sub-registers.
390 unsigned getNumSubRegIndices() const {
391 return NumSubRegIndices;
394 /// \brief Return the number of (native) register units in the
395 /// target. Register units are numbered from 0 to getNumRegUnits() - 1. They
396 /// can be accessed through MCRegUnitIterator defined below.
397 unsigned getNumRegUnits() const {
401 /// \brief Map a target register to an equivalent dwarf register
402 /// number. Returns -1 if there is no equivalent value. The second
403 /// parameter allows targets to use different numberings for EH info and
405 int getDwarfRegNum(unsigned RegNum, bool isEH) const;
407 /// \brief Map a dwarf register back to a target register.
408 int getLLVMRegNum(unsigned RegNum, bool isEH) const;
410 /// \brief Map a DWARF EH register back to a target register (same as
411 /// getLLVMRegNum(RegNum, true)) but return -1 if there is no mapping,
412 /// rather than asserting that there must be one.
413 int getLLVMRegNumFromEH(unsigned RegNum) const;
415 /// \brief Map a target EH register number to an equivalent DWARF register
417 int getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const;
419 /// \brief Map a target register to an equivalent SEH register
420 /// number. Returns LLVM register number if there is no equivalent value.
421 int getSEHRegNum(unsigned RegNum) const;
423 /// \brief Map a target register to an equivalent CodeView register
425 int getCodeViewRegNum(unsigned RegNum) const;
427 regclass_iterator regclass_begin() const { return Classes; }
428 regclass_iterator regclass_end() const { return Classes+NumClasses; }
429 iterator_range<regclass_iterator> regclasses() const {
430 return make_range(regclass_begin(), regclass_end());
433 unsigned getNumRegClasses() const {
434 return (unsigned)(regclass_end()-regclass_begin());
437 /// \brief Returns the register class associated with the enumeration
438 /// value. See class MCOperandInfo.
439 const MCRegisterClass& getRegClass(unsigned i) const {
440 assert(i < getNumRegClasses() && "Register Class ID out of range");
444 const char *getRegClassName(const MCRegisterClass *Class) const {
445 return RegClassStrings + Class->NameIdx;
448 /// \brief Returns the encoding for RegNo
449 uint16_t getEncodingValue(unsigned RegNo) const {
450 assert(RegNo < NumRegs &&
451 "Attempting to get encoding for invalid register number!");
452 return RegEncodingTable[RegNo];
455 /// \brief Returns true if RegB is a sub-register of RegA.
456 bool isSubRegister(unsigned RegA, unsigned RegB) const {
457 return isSuperRegister(RegB, RegA);
460 /// \brief Returns true if RegB is a super-register of RegA.
461 bool isSuperRegister(unsigned RegA, unsigned RegB) const;
463 /// \brief Returns true if RegB is a sub-register of RegA or if RegB == RegA.
464 bool isSubRegisterEq(unsigned RegA, unsigned RegB) const {
465 return isSuperRegisterEq(RegB, RegA);
468 /// \brief Returns true if RegB is a super-register of RegA or if
470 bool isSuperRegisterEq(unsigned RegA, unsigned RegB) const {
471 return RegA == RegB || isSuperRegister(RegA, RegB);
474 /// \brief Returns true if RegB is a super-register or sub-register of RegA
475 /// or if RegB == RegA.
476 bool isSuperOrSubRegisterEq(unsigned RegA, unsigned RegB) const {
477 return isSubRegisterEq(RegA, RegB) || isSuperRegister(RegA, RegB);
481 //===----------------------------------------------------------------------===//
482 // Register List Iterators
483 //===----------------------------------------------------------------------===//
485 // MCRegisterInfo provides lists of super-registers, sub-registers, and
486 // aliasing registers. Use these iterator classes to traverse the lists.
488 /// MCSubRegIterator enumerates all sub-registers of Reg.
489 /// If IncludeSelf is set, Reg itself is included in the list.
490 class MCSubRegIterator : public MCRegisterInfo::DiffListIterator {
492 MCSubRegIterator(unsigned Reg, const MCRegisterInfo *MCRI,
493 bool IncludeSelf = false) {
494 init(Reg, MCRI->DiffLists + MCRI->get(Reg).SubRegs);
495 // Initially, the iterator points to Reg itself.
501 /// Iterator that enumerates the sub-registers of a Reg and the associated
502 /// sub-register indices.
503 class MCSubRegIndexIterator {
504 MCSubRegIterator SRIter;
505 const uint16_t *SRIndex;
508 /// Constructs an iterator that traverses subregisters and their
509 /// associated subregister indices.
510 MCSubRegIndexIterator(unsigned Reg, const MCRegisterInfo *MCRI)
511 : SRIter(Reg, MCRI) {
512 SRIndex = MCRI->SubRegIndices + MCRI->get(Reg).SubRegIndices;
515 /// Returns current sub-register.
516 unsigned getSubReg() const {
520 /// Returns sub-register index of the current sub-register.
521 unsigned getSubRegIndex() const {
525 /// Returns true if this iterator is not yet at the end.
526 bool isValid() const { return SRIter.isValid(); }
528 /// Moves to the next position.
535 /// MCSuperRegIterator enumerates all super-registers of Reg.
536 /// If IncludeSelf is set, Reg itself is included in the list.
537 class MCSuperRegIterator : public MCRegisterInfo::DiffListIterator {
539 MCSuperRegIterator() = default;
541 MCSuperRegIterator(unsigned Reg, const MCRegisterInfo *MCRI,
542 bool IncludeSelf = false) {
543 init(Reg, MCRI->DiffLists + MCRI->get(Reg).SuperRegs);
544 // Initially, the iterator points to Reg itself.
550 // Definition for isSuperRegister. Put it down here since it needs the
551 // iterator defined above in addition to the MCRegisterInfo class itself.
552 inline bool MCRegisterInfo::isSuperRegister(unsigned RegA, unsigned RegB) const{
553 for (MCSuperRegIterator I(RegA, this); I.isValid(); ++I)
559 //===----------------------------------------------------------------------===//
561 //===----------------------------------------------------------------------===//
563 // Register units are used to compute register aliasing. Every register has at
564 // least one register unit, but it can have more. Two registers overlap if and
565 // only if they have a common register unit.
567 // A target with a complicated sub-register structure will typically have many
568 // fewer register units than actual registers. MCRI::getNumRegUnits() returns
569 // the number of register units in the target.
571 // MCRegUnitIterator enumerates a list of register units for Reg. The list is
572 // in ascending numerical order.
573 class MCRegUnitIterator : public MCRegisterInfo::DiffListIterator {
575 /// MCRegUnitIterator - Create an iterator that traverses the register units
577 MCRegUnitIterator() = default;
579 MCRegUnitIterator(unsigned Reg, const MCRegisterInfo *MCRI) {
580 assert(Reg && "Null register has no regunits");
581 // Decode the RegUnits MCRegisterDesc field.
582 unsigned RU = MCRI->get(Reg).RegUnits;
583 unsigned Scale = RU & 15;
584 unsigned Offset = RU >> 4;
586 // Initialize the iterator to Reg * Scale, and the List pointer to
587 // DiffLists + Offset.
588 init(Reg * Scale, MCRI->DiffLists + Offset);
590 // That may not be a valid unit, we need to advance by one to get the real
591 // unit number. The first differential can be 0 which would normally
592 // terminate the list, but since we know every register has at least one
593 // unit, we can allow a 0 differential here.
598 /// MCRegUnitMaskIterator enumerates a list of register units and their
599 /// associated lane masks for Reg. The register units are in ascending
601 class MCRegUnitMaskIterator {
602 MCRegUnitIterator RUIter;
603 const LaneBitmask *MaskListIter;
606 MCRegUnitMaskIterator() = default;
608 /// Constructs an iterator that traverses the register units and their
609 /// associated LaneMasks in Reg.
610 MCRegUnitMaskIterator(unsigned Reg, const MCRegisterInfo *MCRI)
611 : RUIter(Reg, MCRI) {
612 uint16_t Idx = MCRI->get(Reg).RegUnitLaneMasks;
613 MaskListIter = &MCRI->RegUnitMaskSequences[Idx];
616 /// Returns a (RegUnit, LaneMask) pair.
617 std::pair<unsigned,LaneBitmask> operator*() const {
618 return std::make_pair(*RUIter, *MaskListIter);
621 /// Returns true if this iterator is not yet at the end.
622 bool isValid() const { return RUIter.isValid(); }
624 /// Moves to the next position.
631 // Each register unit has one or two root registers. The complete set of
632 // registers containing a register unit is the union of the roots and their
633 // super-registers. All registers aliasing Unit can be visited like this:
635 // for (MCRegUnitRootIterator RI(Unit, MCRI); RI.isValid(); ++RI) {
636 // for (MCSuperRegIterator SI(*RI, MCRI, true); SI.isValid(); ++SI)
640 /// MCRegUnitRootIterator enumerates the root registers of a register unit.
641 class MCRegUnitRootIterator {
646 MCRegUnitRootIterator() = default;
648 MCRegUnitRootIterator(unsigned RegUnit, const MCRegisterInfo *MCRI) {
649 assert(RegUnit < MCRI->getNumRegUnits() && "Invalid register unit");
650 Reg0 = MCRI->RegUnitRoots[RegUnit][0];
651 Reg1 = MCRI->RegUnitRoots[RegUnit][1];
654 /// \brief Dereference to get the current root register.
655 unsigned operator*() const {
659 /// \brief Check if the iterator is at the end of the list.
660 bool isValid() const {
664 /// \brief Preincrement to move to the next root register.
666 assert(isValid() && "Cannot move off the end of the list.");
672 /// MCRegAliasIterator enumerates all registers aliasing Reg. If IncludeSelf is
673 /// set, Reg itself is included in the list. This iterator does not guarantee
674 /// any ordering or that entries are unique.
675 class MCRegAliasIterator {
678 const MCRegisterInfo *MCRI;
681 MCRegUnitIterator RI;
682 MCRegUnitRootIterator RRI;
683 MCSuperRegIterator SI;
686 MCRegAliasIterator(unsigned Reg, const MCRegisterInfo *MCRI,
688 : Reg(Reg), MCRI(MCRI), IncludeSelf(IncludeSelf) {
689 // Initialize the iterators.
690 for (RI = MCRegUnitIterator(Reg, MCRI); RI.isValid(); ++RI) {
691 for (RRI = MCRegUnitRootIterator(*RI, MCRI); RRI.isValid(); ++RRI) {
692 for (SI = MCSuperRegIterator(*RRI, MCRI, true); SI.isValid(); ++SI) {
693 if (!(!IncludeSelf && Reg == *SI))
700 bool isValid() const { return RI.isValid(); }
702 unsigned operator*() const {
703 assert(SI.isValid() && "Cannot dereference an invalid iterator.");
708 // Assuming SI is valid.
710 if (SI.isValid()) return;
714 SI = MCSuperRegIterator(*RRI, MCRI, true);
720 RRI = MCRegUnitRootIterator(*RI, MCRI);
721 SI = MCSuperRegIterator(*RRI, MCRI, true);
726 assert(isValid() && "Cannot move off the end of the list.");
728 while (!IncludeSelf && isValid() && *SI == Reg);
732 } // end namespace llvm
734 #endif // LLVM_MC_MCREGISTERINFO_H