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
23 namespace llvm {
24
25 /// An unsigned integer type large enough to represent all physical registers,
26 /// but not necessarily virtual registers.
27 typedef uint16_t MCPhysReg;
28
29 /// MCRegisterClass - Base class of TargetRegisterClass.
30 class MCRegisterClass {
31 public:
32 typedef const MCPhysReg* iterator;
33 typedef const MCPhysReg* const_iterator;
34
35 const iterator RegsBegin;
36 const uint8_t *const RegSet;
37 const uint32_t NameIdx;
38 const uint16_t RegsSize;
39 const uint16_t RegSetSize;
40 const uint16_t ID;
41 const uint16_t RegSize, Alignment; // Size & Alignment of register in bytes
42 const int8_t CopyCost;
43 const bool Allocatable;
44
45 /// getID() - Return the register class ID number.
46 ///
getID()47 unsigned getID() const { return ID; }
48
49 /// begin/end - Return all of the registers in this class.
50 ///
begin()51 iterator begin() const { return RegsBegin; }
end()52 iterator end() const { return RegsBegin + RegsSize; }
53
54 /// getNumRegs - Return the number of registers in this class.
55 ///
getNumRegs()56 unsigned getNumRegs() const { return RegsSize; }
57
58 /// getRegister - Return the specified register in the class.
59 ///
getRegister(unsigned i)60 unsigned getRegister(unsigned i) const {
61 assert(i < getNumRegs() && "Register number out of range!");
62 return RegsBegin[i];
63 }
64
65 /// contains - Return true if the specified register is included in this
66 /// register class. This does not include virtual registers.
contains(unsigned Reg)67 bool contains(unsigned Reg) const {
68 unsigned InByte = Reg % 8;
69 unsigned Byte = Reg / 8;
70 if (Byte >= RegSetSize)
71 return false;
72 return (RegSet[Byte] & (1 << InByte)) != 0;
73 }
74
75 /// contains - Return true if both registers are in this class.
contains(unsigned Reg1,unsigned Reg2)76 bool contains(unsigned Reg1, unsigned Reg2) const {
77 return contains(Reg1) && contains(Reg2);
78 }
79
80 /// getSize - Return the size of the register in bytes, which is also the size
81 /// of a stack slot allocated to hold a spilled copy of this register.
getSize()82 unsigned getSize() const { return RegSize; }
83
84 /// getAlignment - Return the minimum required alignment for a register of
85 /// this class.
getAlignment()86 unsigned getAlignment() const { return Alignment; }
87
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.
getCopyCost()91 int getCopyCost() const { return CopyCost; }
92
93 /// isAllocatable - Return true if this register class may be used to create
94 /// virtual registers.
isAllocatable()95 bool isAllocatable() const { return Allocatable; }
96 };
97
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.
104 ///
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
109
110 // Offset into MCRI::SubRegIndices of a list of sub-register indices for each
111 // sub-register in SubRegs.
112 uint32_t SubRegIndices;
113
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.
116 uint32_t RegUnits;
117
118 /// Index into list with lane mask sequences. The sequence contains a lanemask
119 /// for every register unit.
120 uint16_t RegUnitLaneMasks;
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 ///
135 class MCRegisterInfo {
136 public:
137 typedef const MCRegisterClass *regclass_iterator;
138
139 /// DwarfLLVMRegPair - Emitted by tablegen so Dwarf<->LLVM reg mappings can be
140 /// performed with a binary search.
141 struct DwarfLLVMRegPair {
142 unsigned FromReg;
143 unsigned ToReg;
144
145 bool operator<(DwarfLLVMRegPair RHS) const { return FromReg < RHS.FromReg; }
146 };
147
148 /// SubRegCoveredBits - Emitted by tablegen: bit range covered by a subreg
149 /// index, -1 in any being invalid.
150 struct SubRegCoveredBits {
151 uint16_t Offset;
152 uint16_t Size;
153 };
154 private:
155 const MCRegisterDesc *Desc; // Pointer to the descriptor array
156 unsigned NumRegs; // Number of entries in the array
157 unsigned RAReg; // Return address register
158 unsigned PCReg; // Program counter register
159 const MCRegisterClass *Classes; // Pointer to the regclass array
160 unsigned NumClasses; // Number of entries in the array
161 unsigned NumRegUnits; // Number of regunits.
162 const MCPhysReg (*RegUnitRoots)[2]; // Pointer to regunit root table.
163 const MCPhysReg *DiffLists; // Pointer to the difflists array
164 const unsigned *RegUnitMaskSequences; // Pointer to lane mask sequences
165 // for register units.
166 const char *RegStrings; // Pointer to the string table.
167 const char *RegClassStrings; // Pointer to the class strings.
168 const uint16_t *SubRegIndices; // Pointer to the subreg lookup
169 // array.
170 const SubRegCoveredBits *SubRegIdxRanges; // Pointer to the subreg covered
171 // bit ranges array.
172 unsigned NumSubRegIndices; // Number of subreg indices.
173 const uint16_t *RegEncodingTable; // Pointer to array of register
174 // encodings.
175
176 unsigned L2DwarfRegsSize;
177 unsigned EHL2DwarfRegsSize;
178 unsigned Dwarf2LRegsSize;
179 unsigned EHDwarf2LRegsSize;
180 const DwarfLLVMRegPair *L2DwarfRegs; // LLVM to Dwarf regs mapping
181 const DwarfLLVMRegPair *EHL2DwarfRegs; // LLVM to Dwarf regs mapping EH
182 const DwarfLLVMRegPair *Dwarf2LRegs; // Dwarf to LLVM regs mapping
183 const DwarfLLVMRegPair *EHDwarf2LRegs; // Dwarf to LLVM regs mapping EH
184 DenseMap<unsigned, int> L2SEHRegs; // LLVM to SEH regs mapping
185
186 public:
187 /// DiffListIterator - Base iterator class that can traverse the
188 /// differentially encoded register and regunit lists in DiffLists.
189 /// Don't use this class directly, use one of the specialized sub-classes
190 /// defined below.
191 class DiffListIterator {
192 uint16_t Val;
193 const MCPhysReg *List;
194
195 protected:
196 /// Create an invalid iterator. Call init() to point to something useful.
DiffListIterator()197 DiffListIterator() : Val(0), List(nullptr) {}
198
199 /// init - Point the iterator to InitVal, decoding subsequent values from
200 /// DiffList. The iterator will initially point to InitVal, sub-classes are
201 /// responsible for skipping the seed value if it is not part of the list.
init(MCPhysReg InitVal,const MCPhysReg * DiffList)202 void init(MCPhysReg InitVal, const MCPhysReg *DiffList) {
203 Val = InitVal;
204 List = DiffList;
205 }
206
207 /// advance - Move to the next list position, return the applied
208 /// differential. This function does not detect the end of the list, that
209 /// is the caller's responsibility (by checking for a 0 return value).
advance()210 unsigned advance() {
211 assert(isValid() && "Cannot move off the end of the list.");
212 MCPhysReg D = *List++;
213 Val += D;
214 return D;
215 }
216
217 public:
218
219 /// isValid - returns true if this iterator is not yet at the end.
isValid()220 bool isValid() const { return List; }
221
222 /// Dereference the iterator to get the value at the current position.
223 unsigned operator*() const { return Val; }
224
225 /// Pre-increment to move to the next position.
226 void operator++() {
227 // The end of the list is encoded as a 0 differential.
228 if (!advance())
229 List = nullptr;
230 }
231 };
232
233 // These iterators are allowed to sub-class DiffListIterator and access
234 // internal list pointers.
235 friend class MCSubRegIterator;
236 friend class MCSubRegIndexIterator;
237 friend class MCSuperRegIterator;
238 friend class MCRegUnitIterator;
239 friend class MCRegUnitMaskIterator;
240 friend class MCRegUnitRootIterator;
241
242 /// \brief Initialize MCRegisterInfo, called by TableGen
243 /// auto-generated routines. *DO NOT USE*.
InitMCRegisterInfo(const MCRegisterDesc * D,unsigned NR,unsigned RA,unsigned PC,const MCRegisterClass * C,unsigned NC,const MCPhysReg (* RURoots)[2],unsigned NRU,const MCPhysReg * DL,const unsigned * RUMS,const char * Strings,const char * ClassStrings,const uint16_t * SubIndices,unsigned NumIndices,const SubRegCoveredBits * SubIdxRanges,const uint16_t * RET)244 void InitMCRegisterInfo(const MCRegisterDesc *D, unsigned NR, unsigned RA,
245 unsigned PC,
246 const MCRegisterClass *C, unsigned NC,
247 const MCPhysReg (*RURoots)[2],
248 unsigned NRU,
249 const MCPhysReg *DL,
250 const unsigned *RUMS,
251 const char *Strings,
252 const char *ClassStrings,
253 const uint16_t *SubIndices,
254 unsigned NumIndices,
255 const SubRegCoveredBits *SubIdxRanges,
256 const uint16_t *RET) {
257 Desc = D;
258 NumRegs = NR;
259 RAReg = RA;
260 PCReg = PC;
261 Classes = C;
262 DiffLists = DL;
263 RegUnitMaskSequences = RUMS;
264 RegStrings = Strings;
265 RegClassStrings = ClassStrings;
266 NumClasses = NC;
267 RegUnitRoots = RURoots;
268 NumRegUnits = NRU;
269 SubRegIndices = SubIndices;
270 NumSubRegIndices = NumIndices;
271 SubRegIdxRanges = SubIdxRanges;
272 RegEncodingTable = RET;
273 }
274
275 /// \brief Used to initialize LLVM register to Dwarf
276 /// register number mapping. Called by TableGen auto-generated routines.
277 /// *DO NOT USE*.
mapLLVMRegsToDwarfRegs(const DwarfLLVMRegPair * Map,unsigned Size,bool isEH)278 void mapLLVMRegsToDwarfRegs(const DwarfLLVMRegPair *Map, unsigned Size,
279 bool isEH) {
280 if (isEH) {
281 EHL2DwarfRegs = Map;
282 EHL2DwarfRegsSize = Size;
283 } else {
284 L2DwarfRegs = Map;
285 L2DwarfRegsSize = Size;
286 }
287 }
288
289 /// \brief Used to initialize Dwarf register to LLVM
290 /// register number mapping. Called by TableGen auto-generated routines.
291 /// *DO NOT USE*.
mapDwarfRegsToLLVMRegs(const DwarfLLVMRegPair * Map,unsigned Size,bool isEH)292 void mapDwarfRegsToLLVMRegs(const DwarfLLVMRegPair *Map, unsigned Size,
293 bool isEH) {
294 if (isEH) {
295 EHDwarf2LRegs = Map;
296 EHDwarf2LRegsSize = Size;
297 } else {
298 Dwarf2LRegs = Map;
299 Dwarf2LRegsSize = Size;
300 }
301 }
302
303 /// mapLLVMRegToSEHReg - Used to initialize LLVM register to SEH register
304 /// number mapping. By default the SEH register number is just the same
305 /// as the LLVM register number.
306 /// FIXME: TableGen these numbers. Currently this requires target specific
307 /// initialization code.
mapLLVMRegToSEHReg(unsigned LLVMReg,int SEHReg)308 void mapLLVMRegToSEHReg(unsigned LLVMReg, int SEHReg) {
309 L2SEHRegs[LLVMReg] = SEHReg;
310 }
311
312 /// \brief This method should return the register where the return
313 /// address can be found.
getRARegister()314 unsigned getRARegister() const {
315 return RAReg;
316 }
317
318 /// Return the register which is the program counter.
getProgramCounter()319 unsigned getProgramCounter() const {
320 return PCReg;
321 }
322
323 const MCRegisterDesc &operator[](unsigned RegNo) const {
324 assert(RegNo < NumRegs &&
325 "Attempting to access record for invalid register number!");
326 return Desc[RegNo];
327 }
328
329 /// \brief Provide a get method, equivalent to [], but more useful with a
330 /// pointer to this object.
get(unsigned RegNo)331 const MCRegisterDesc &get(unsigned RegNo) const {
332 return operator[](RegNo);
333 }
334
335 /// \brief Returns the physical register number of sub-register "Index"
336 /// for physical register RegNo. Return zero if the sub-register does not
337 /// exist.
338 unsigned getSubReg(unsigned Reg, unsigned Idx) const;
339
340 /// \brief Return a super-register of the specified register
341 /// Reg so its sub-register of index SubIdx is Reg.
342 unsigned getMatchingSuperReg(unsigned Reg, unsigned SubIdx,
343 const MCRegisterClass *RC) const;
344
345 /// \brief For a given register pair, return the sub-register index
346 /// if the second register is a sub-register of the first. Return zero
347 /// otherwise.
348 unsigned getSubRegIndex(unsigned RegNo, unsigned SubRegNo) const;
349
350 /// \brief Get the size of the bit range covered by a sub-register index.
351 /// If the index isn't continuous, return the sum of the sizes of its parts.
352 /// If the index is used to access subregisters of different sizes, return -1.
353 unsigned getSubRegIdxSize(unsigned Idx) const;
354
355 /// \brief Get the offset of the bit range covered by a sub-register index.
356 /// If an Offset doesn't make sense (the index isn't continuous, or is used to
357 /// access sub-registers at different offsets), return -1.
358 unsigned getSubRegIdxOffset(unsigned Idx) const;
359
360 /// \brief Return the human-readable symbolic target-specific name for the
361 /// specified physical register.
getName(unsigned RegNo)362 const char *getName(unsigned RegNo) const {
363 return RegStrings + get(RegNo).Name;
364 }
365
366 /// \brief Return the number of registers this target has (useful for
367 /// sizing arrays holding per register information)
getNumRegs()368 unsigned getNumRegs() const {
369 return NumRegs;
370 }
371
372 /// \brief Return the number of sub-register indices
373 /// understood by the target. Index 0 is reserved for the no-op sub-register,
374 /// while 1 to getNumSubRegIndices() - 1 represent real sub-registers.
getNumSubRegIndices()375 unsigned getNumSubRegIndices() const {
376 return NumSubRegIndices;
377 }
378
379 /// \brief Return the number of (native) register units in the
380 /// target. Register units are numbered from 0 to getNumRegUnits() - 1. They
381 /// can be accessed through MCRegUnitIterator defined below.
getNumRegUnits()382 unsigned getNumRegUnits() const {
383 return NumRegUnits;
384 }
385
386 /// \brief Map a target register to an equivalent dwarf register
387 /// number. Returns -1 if there is no equivalent value. The second
388 /// parameter allows targets to use different numberings for EH info and
389 /// debugging info.
390 int getDwarfRegNum(unsigned RegNum, bool isEH) const;
391
392 /// \brief Map a dwarf register back to a target register.
393 int getLLVMRegNum(unsigned RegNum, bool isEH) const;
394
395 /// \brief Map a target register to an equivalent SEH register
396 /// number. Returns LLVM register number if there is no equivalent value.
397 int getSEHRegNum(unsigned RegNum) const;
398
regclass_begin()399 regclass_iterator regclass_begin() const { return Classes; }
regclass_end()400 regclass_iterator regclass_end() const { return Classes+NumClasses; }
401
getNumRegClasses()402 unsigned getNumRegClasses() const {
403 return (unsigned)(regclass_end()-regclass_begin());
404 }
405
406 /// \brief Returns the register class associated with the enumeration
407 /// value. See class MCOperandInfo.
getRegClass(unsigned i)408 const MCRegisterClass& getRegClass(unsigned i) const {
409 assert(i < getNumRegClasses() && "Register Class ID out of range");
410 return Classes[i];
411 }
412
getRegClassName(const MCRegisterClass * Class)413 const char *getRegClassName(const MCRegisterClass *Class) const {
414 return RegClassStrings + Class->NameIdx;
415 }
416
417 /// \brief Returns the encoding for RegNo
getEncodingValue(unsigned RegNo)418 uint16_t getEncodingValue(unsigned RegNo) const {
419 assert(RegNo < NumRegs &&
420 "Attempting to get encoding for invalid register number!");
421 return RegEncodingTable[RegNo];
422 }
423
424 /// \brief Returns true if RegB is a sub-register of RegA.
isSubRegister(unsigned RegA,unsigned RegB)425 bool isSubRegister(unsigned RegA, unsigned RegB) const {
426 return isSuperRegister(RegB, RegA);
427 }
428
429 /// \brief Returns true if RegB is a super-register of RegA.
430 bool isSuperRegister(unsigned RegA, unsigned RegB) const;
431
432 /// \brief Returns true if RegB is a sub-register of RegA or if RegB == RegA.
isSubRegisterEq(unsigned RegA,unsigned RegB)433 bool isSubRegisterEq(unsigned RegA, unsigned RegB) const {
434 return isSuperRegisterEq(RegB, RegA);
435 }
436
437 /// \brief Returns true if RegB is a super-register of RegA or if
438 /// RegB == RegA.
isSuperRegisterEq(unsigned RegA,unsigned RegB)439 bool isSuperRegisterEq(unsigned RegA, unsigned RegB) const {
440 return RegA == RegB || isSuperRegister(RegA, RegB);
441 }
442
443 };
444
445 //===----------------------------------------------------------------------===//
446 // Register List Iterators
447 //===----------------------------------------------------------------------===//
448
449 // MCRegisterInfo provides lists of super-registers, sub-registers, and
450 // aliasing registers. Use these iterator classes to traverse the lists.
451
452 /// MCSubRegIterator enumerates all sub-registers of Reg.
453 /// If IncludeSelf is set, Reg itself is included in the list.
454 class MCSubRegIterator : public MCRegisterInfo::DiffListIterator {
455 public:
456 MCSubRegIterator(unsigned Reg, const MCRegisterInfo *MCRI,
457 bool IncludeSelf = false) {
458 init(Reg, MCRI->DiffLists + MCRI->get(Reg).SubRegs);
459 // Initially, the iterator points to Reg itself.
460 if (!IncludeSelf)
461 ++*this;
462 }
463 };
464
465 /// Iterator that enumerates the sub-registers of a Reg and the associated
466 /// sub-register indices.
467 class MCSubRegIndexIterator {
468 MCSubRegIterator SRIter;
469 const uint16_t *SRIndex;
470 public:
471 /// Constructs an iterator that traverses subregisters and their
472 /// associated subregister indices.
MCSubRegIndexIterator(unsigned Reg,const MCRegisterInfo * MCRI)473 MCSubRegIndexIterator(unsigned Reg, const MCRegisterInfo *MCRI)
474 : SRIter(Reg, MCRI) {
475 SRIndex = MCRI->SubRegIndices + MCRI->get(Reg).SubRegIndices;
476 }
477
478 /// Returns current sub-register.
getSubReg()479 unsigned getSubReg() const {
480 return *SRIter;
481 }
482 /// Returns sub-register index of the current sub-register.
getSubRegIndex()483 unsigned getSubRegIndex() const {
484 return *SRIndex;
485 }
486
487 /// Returns true if this iterator is not yet at the end.
isValid()488 bool isValid() const { return SRIter.isValid(); }
489
490 /// Moves to the next position.
491 void operator++() {
492 ++SRIter;
493 ++SRIndex;
494 }
495 };
496
497 /// MCSuperRegIterator enumerates all super-registers of Reg.
498 /// If IncludeSelf is set, Reg itself is included in the list.
499 class MCSuperRegIterator : public MCRegisterInfo::DiffListIterator {
500 public:
MCSuperRegIterator()501 MCSuperRegIterator() {}
502 MCSuperRegIterator(unsigned Reg, const MCRegisterInfo *MCRI,
503 bool IncludeSelf = false) {
504 init(Reg, MCRI->DiffLists + MCRI->get(Reg).SuperRegs);
505 // Initially, the iterator points to Reg itself.
506 if (!IncludeSelf)
507 ++*this;
508 }
509 };
510
511 // Definition for isSuperRegister. Put it down here since it needs the
512 // iterator defined above in addition to the MCRegisterInfo class itself.
isSuperRegister(unsigned RegA,unsigned RegB)513 inline bool MCRegisterInfo::isSuperRegister(unsigned RegA, unsigned RegB) const{
514 for (MCSuperRegIterator I(RegA, this); I.isValid(); ++I)
515 if (*I == RegB)
516 return true;
517 return false;
518 }
519
520 //===----------------------------------------------------------------------===//
521 // Register Units
522 //===----------------------------------------------------------------------===//
523
524 // Register units are used to compute register aliasing. Every register has at
525 // least one register unit, but it can have more. Two registers overlap if and
526 // only if they have a common register unit.
527 //
528 // A target with a complicated sub-register structure will typically have many
529 // fewer register units than actual registers. MCRI::getNumRegUnits() returns
530 // the number of register units in the target.
531
532 // MCRegUnitIterator enumerates a list of register units for Reg. The list is
533 // in ascending numerical order.
534 class MCRegUnitIterator : public MCRegisterInfo::DiffListIterator {
535 public:
536 /// MCRegUnitIterator - Create an iterator that traverses the register units
537 /// in Reg.
MCRegUnitIterator()538 MCRegUnitIterator() {}
MCRegUnitIterator(unsigned Reg,const MCRegisterInfo * MCRI)539 MCRegUnitIterator(unsigned Reg, const MCRegisterInfo *MCRI) {
540 assert(Reg && "Null register has no regunits");
541 // Decode the RegUnits MCRegisterDesc field.
542 unsigned RU = MCRI->get(Reg).RegUnits;
543 unsigned Scale = RU & 15;
544 unsigned Offset = RU >> 4;
545
546 // Initialize the iterator to Reg * Scale, and the List pointer to
547 // DiffLists + Offset.
548 init(Reg * Scale, MCRI->DiffLists + Offset);
549
550 // That may not be a valid unit, we need to advance by one to get the real
551 // unit number. The first differential can be 0 which would normally
552 // terminate the list, but since we know every register has at least one
553 // unit, we can allow a 0 differential here.
554 advance();
555 }
556 };
557
558 /// MCRegUnitIterator enumerates a list of register units and their associated
559 /// lane masks for Reg. The register units are in ascending numerical order.
560 class MCRegUnitMaskIterator {
561 MCRegUnitIterator RUIter;
562 const unsigned *MaskListIter;
563 public:
MCRegUnitMaskIterator()564 MCRegUnitMaskIterator() {}
565 /// Constructs an iterator that traverses the register units and their
566 /// associated LaneMasks in Reg.
MCRegUnitMaskIterator(unsigned Reg,const MCRegisterInfo * MCRI)567 MCRegUnitMaskIterator(unsigned Reg, const MCRegisterInfo *MCRI)
568 : RUIter(Reg, MCRI) {
569 uint16_t Idx = MCRI->get(Reg).RegUnitLaneMasks;
570 MaskListIter = &MCRI->RegUnitMaskSequences[Idx];
571 }
572
573 /// Returns a (RegUnit, LaneMask) pair.
574 std::pair<unsigned,unsigned> operator*() const {
575 return std::make_pair(*RUIter, *MaskListIter);
576 }
577
578 /// Returns true if this iterator is not yet at the end.
isValid()579 bool isValid() const { return RUIter.isValid(); }
580
581 /// Moves to the next position.
582 void operator++() {
583 ++MaskListIter;
584 ++RUIter;
585 }
586 };
587
588 // Each register unit has one or two root registers. The complete set of
589 // registers containing a register unit is the union of the roots and their
590 // super-registers. All registers aliasing Unit can be visited like this:
591 //
592 // for (MCRegUnitRootIterator RI(Unit, MCRI); RI.isValid(); ++RI) {
593 // for (MCSuperRegIterator SI(*RI, MCRI, true); SI.isValid(); ++SI)
594 // visit(*SI);
595 // }
596
597 /// MCRegUnitRootIterator enumerates the root registers of a register unit.
598 class MCRegUnitRootIterator {
599 uint16_t Reg0;
600 uint16_t Reg1;
601 public:
MCRegUnitRootIterator()602 MCRegUnitRootIterator() : Reg0(0), Reg1(0) {}
MCRegUnitRootIterator(unsigned RegUnit,const MCRegisterInfo * MCRI)603 MCRegUnitRootIterator(unsigned RegUnit, const MCRegisterInfo *MCRI) {
604 assert(RegUnit < MCRI->getNumRegUnits() && "Invalid register unit");
605 Reg0 = MCRI->RegUnitRoots[RegUnit][0];
606 Reg1 = MCRI->RegUnitRoots[RegUnit][1];
607 }
608
609 /// \brief Dereference to get the current root register.
610 unsigned operator*() const {
611 return Reg0;
612 }
613
614 /// \brief Check if the iterator is at the end of the list.
isValid()615 bool isValid() const {
616 return Reg0;
617 }
618
619 /// \brief Preincrement to move to the next root register.
620 void operator++() {
621 assert(isValid() && "Cannot move off the end of the list.");
622 Reg0 = Reg1;
623 Reg1 = 0;
624 }
625 };
626
627 /// MCRegAliasIterator enumerates all registers aliasing Reg. If IncludeSelf is
628 /// set, Reg itself is included in the list. This iterator does not guarantee
629 /// any ordering or that entries are unique.
630 class MCRegAliasIterator {
631 private:
632 unsigned Reg;
633 const MCRegisterInfo *MCRI;
634 bool IncludeSelf;
635
636 MCRegUnitIterator RI;
637 MCRegUnitRootIterator RRI;
638 MCSuperRegIterator SI;
639 public:
MCRegAliasIterator(unsigned Reg,const MCRegisterInfo * MCRI,bool IncludeSelf)640 MCRegAliasIterator(unsigned Reg, const MCRegisterInfo *MCRI,
641 bool IncludeSelf)
642 : Reg(Reg), MCRI(MCRI), IncludeSelf(IncludeSelf) {
643
644 // Initialize the iterators.
645 for (RI = MCRegUnitIterator(Reg, MCRI); RI.isValid(); ++RI) {
646 for (RRI = MCRegUnitRootIterator(*RI, MCRI); RRI.isValid(); ++RRI) {
647 for (SI = MCSuperRegIterator(*RRI, MCRI, true); SI.isValid(); ++SI) {
648 if (!(!IncludeSelf && Reg == *SI))
649 return;
650 }
651 }
652 }
653 }
654
isValid()655 bool isValid() const {
656 return RI.isValid();
657 }
658
659 unsigned operator*() const {
660 assert (SI.isValid() && "Cannot dereference an invalid iterator.");
661 return *SI;
662 }
663
advance()664 void advance() {
665 // Assuming SI is valid.
666 ++SI;
667 if (SI.isValid()) return;
668
669 ++RRI;
670 if (RRI.isValid()) {
671 SI = MCSuperRegIterator(*RRI, MCRI, true);
672 return;
673 }
674
675 ++RI;
676 if (RI.isValid()) {
677 RRI = MCRegUnitRootIterator(*RI, MCRI);
678 SI = MCSuperRegIterator(*RRI, MCRI, true);
679 }
680 }
681
682 void operator++() {
683 assert(isValid() && "Cannot move off the end of the list.");
684 do advance();
685 while (!IncludeSelf && isValid() && *SI == Reg);
686 }
687 };
688
689 } // End llvm namespace
690
691 #endif
692