1 //=== Target/TargetRegisterInfo.h - Target Register Information -*- 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_TARGET_TARGETREGISTERINFO_H
17 #define LLVM_TARGET_TARGETREGISTERINFO_H
19 #include "llvm/MC/MCRegisterInfo.h"
20 #include "llvm/CodeGen/MachineBasicBlock.h"
21 #include "llvm/CodeGen/ValueTypes.h"
22 #include "llvm/ADT/ArrayRef.h"
23 #include "llvm/ADT/DenseSet.h"
30 class MachineFunction;
33 template<class T> class SmallVectorImpl;
36 class TargetRegisterClass {
38 typedef const unsigned* iterator;
39 typedef const unsigned* const_iterator;
41 typedef const EVT* vt_iterator;
42 typedef const TargetRegisterClass* const * sc_iterator;
46 const vt_iterator VTs;
47 const sc_iterator SubClasses;
48 const sc_iterator SuperClasses;
49 const sc_iterator SubRegClasses;
50 const sc_iterator SuperRegClasses;
51 const unsigned RegSize, Alignment; // Size & Alignment of register in bytes
53 const bool Allocatable;
54 const iterator RegsBegin, RegsEnd;
55 DenseSet<unsigned> RegSet;
57 TargetRegisterClass(unsigned id,
60 const TargetRegisterClass * const *subcs,
61 const TargetRegisterClass * const *supcs,
62 const TargetRegisterClass * const *subregcs,
63 const TargetRegisterClass * const *superregcs,
64 unsigned RS, unsigned Al, int CC, bool Allocable,
65 iterator RB, iterator RE)
66 : ID(id), Name(name), VTs(vts), SubClasses(subcs), SuperClasses(supcs),
67 SubRegClasses(subregcs), SuperRegClasses(superregcs),
68 RegSize(RS), Alignment(Al), CopyCost(CC), Allocatable(Allocable),
69 RegsBegin(RB), RegsEnd(RE) {
70 for (iterator I = RegsBegin, E = RegsEnd; I != E; ++I)
73 virtual ~TargetRegisterClass() {} // Allow subclasses
75 /// getID() - Return the register class ID number.
77 unsigned getID() const { return ID; }
79 /// getName() - Return the register class name for debugging.
81 const char *getName() const { return Name; }
83 /// begin/end - Return all of the registers in this class.
85 iterator begin() const { return RegsBegin; }
86 iterator end() const { return RegsEnd; }
88 /// getNumRegs - Return the number of registers in this class.
90 unsigned getNumRegs() const { return (unsigned)(RegsEnd-RegsBegin); }
92 /// getRegister - Return the specified register in the class.
94 unsigned getRegister(unsigned i) const {
95 assert(i < getNumRegs() && "Register number out of range!");
99 /// contains - Return true if the specified register is included in this
100 /// register class. This does not include virtual registers.
101 bool contains(unsigned Reg) const {
102 return RegSet.count(Reg);
105 /// contains - Return true if both registers are in this class.
106 bool contains(unsigned Reg1, unsigned Reg2) const {
107 return contains(Reg1) && contains(Reg2);
110 /// hasType - return true if this TargetRegisterClass has the ValueType vt.
112 bool hasType(EVT vt) const {
113 for(int i = 0; VTs[i] != MVT::Other; ++i)
119 /// vt_begin / vt_end - Loop over all of the value types that can be
120 /// represented by values in this register class.
121 vt_iterator vt_begin() const {
125 vt_iterator vt_end() const {
127 while (*I != MVT::Other) ++I;
131 /// subregclasses_begin / subregclasses_end - Loop over all of
132 /// the subreg register classes of this register class.
133 sc_iterator subregclasses_begin() const {
134 return SubRegClasses;
137 sc_iterator subregclasses_end() const {
138 sc_iterator I = SubRegClasses;
139 while (*I != NULL) ++I;
143 /// getSubRegisterRegClass - Return the register class of subregisters with
144 /// index SubIdx, or NULL if no such class exists.
145 const TargetRegisterClass* getSubRegisterRegClass(unsigned SubIdx) const {
146 assert(SubIdx>0 && "Invalid subregister index");
147 return SubRegClasses[SubIdx-1];
150 /// superregclasses_begin / superregclasses_end - Loop over all of
151 /// the superreg register classes of this register class.
152 sc_iterator superregclasses_begin() const {
153 return SuperRegClasses;
156 sc_iterator superregclasses_end() const {
157 sc_iterator I = SuperRegClasses;
158 while (*I != NULL) ++I;
162 /// hasSubClass - return true if the specified TargetRegisterClass
163 /// is a proper subset of this TargetRegisterClass.
164 bool hasSubClass(const TargetRegisterClass *cs) const {
165 for (int i = 0; SubClasses[i] != NULL; ++i)
166 if (SubClasses[i] == cs)
171 /// hasSubClassEq - Returns true if RC is a subclass of or equal to this
173 bool hasSubClassEq(const TargetRegisterClass *RC) const {
174 return RC == this || hasSubClass(RC);
177 /// subclasses_begin / subclasses_end - Loop over all of the classes
178 /// that are proper subsets of this register class.
179 sc_iterator subclasses_begin() const {
183 sc_iterator subclasses_end() const {
184 sc_iterator I = SubClasses;
185 while (*I != NULL) ++I;
189 /// hasSuperClass - return true if the specified TargetRegisterClass is a
190 /// proper superset of this TargetRegisterClass.
191 bool hasSuperClass(const TargetRegisterClass *cs) const {
192 for (int i = 0; SuperClasses[i] != NULL; ++i)
193 if (SuperClasses[i] == cs)
198 /// hasSuperClassEq - Returns true if RC is a superclass of or equal to this
200 bool hasSuperClassEq(const TargetRegisterClass *RC) const {
201 return RC == this || hasSuperClass(RC);
204 /// superclasses_begin / superclasses_end - Loop over all of the classes
205 /// that are proper supersets of this register class.
206 sc_iterator superclasses_begin() const {
210 sc_iterator superclasses_end() const {
211 sc_iterator I = SuperClasses;
212 while (*I != NULL) ++I;
216 /// isASubClass - return true if this TargetRegisterClass is a subset
217 /// class of at least one other TargetRegisterClass.
218 bool isASubClass() const {
219 return SuperClasses[0] != 0;
222 /// getRawAllocationOrder - Returns the preferred order for allocating
223 /// registers from this register class in MF. The raw order comes directly
224 /// from the .td file and may include reserved registers that are not
225 /// allocatable. Register allocators should also make sure to allocate
226 /// callee-saved registers only after all the volatiles are used. The
227 /// RegisterClassInfo class provides filtered allocation orders with
228 /// callee-saved registers moved to the end.
230 /// The MachineFunction argument can be used to tune the allocatable
231 /// registers based on the characteristics of the function, subtarget, or
234 /// By default, this method returns all registers in the class.
237 ArrayRef<unsigned> getRawAllocationOrder(const MachineFunction &MF) const {
238 return ArrayRef<unsigned>(begin(), getNumRegs());
241 /// getSize - Return the size of the register in bytes, which is also the size
242 /// of a stack slot allocated to hold a spilled copy of this register.
243 unsigned getSize() const { return RegSize; }
245 /// getAlignment - Return the minimum required alignment for a register of
247 unsigned getAlignment() const { return Alignment; }
249 /// getCopyCost - Return the cost of copying a value between two registers in
250 /// this class. A negative number means the register class is very expensive
251 /// to copy e.g. status flag register classes.
252 int getCopyCost() const { return CopyCost; }
254 /// isAllocatable - Return true if this register class may be used to create
255 /// virtual registers.
256 bool isAllocatable() const { return Allocatable; }
259 /// TargetRegisterDesc - It's just an alias of MCRegisterDesc.
260 typedef MCRegisterDesc TargetRegisterDesc;
262 /// TargetRegisterInfoDesc - Extra information, not in MCRegisterDesc, about
263 /// registers. These are used by codegen, not by MC.
264 struct TargetRegisterInfoDesc {
265 unsigned CostPerUse; // Extra cost of instructions using register.
266 bool inAllocatableClass; // Register belongs to an allocatable regclass.
269 /// TargetRegisterInfo base class - We assume that the target defines a static
270 /// array of TargetRegisterDesc objects that represent all of the machine
271 /// registers that the target has. As such, we simply have to track a pointer
272 /// to this array so that we can turn register number into a register
275 class TargetRegisterInfo : public MCRegisterInfo {
277 typedef const TargetRegisterClass * const * regclass_iterator;
279 const TargetRegisterInfoDesc *InfoDesc; // Extra desc array for codegen
280 const char *const *SubRegIndexNames; // Names of subreg indexes.
281 regclass_iterator RegClassBegin, RegClassEnd; // List of regclasses
282 int CallFrameSetupOpcode, CallFrameDestroyOpcode;
285 TargetRegisterInfo(const TargetRegisterInfoDesc *ID,
286 regclass_iterator RegClassBegin,
287 regclass_iterator RegClassEnd,
288 const char *const *subregindexnames,
289 int CallFrameSetupOpcode = -1,
290 int CallFrameDestroyOpcode = -1);
291 virtual ~TargetRegisterInfo();
294 // Register numbers can represent physical registers, virtual registers, and
295 // sometimes stack slots. The unsigned values are divided into these ranges:
297 // 0 Not a register, can be used as a sentinel.
298 // [1;2^30) Physical registers assigned by TableGen.
299 // [2^30;2^31) Stack slots. (Rarely used.)
300 // [2^31;2^32) Virtual registers assigned by MachineRegisterInfo.
302 // Further sentinels can be allocated from the small negative integers.
303 // DenseMapInfo<unsigned> uses -1u and -2u.
305 /// isStackSlot - Sometimes it is useful the be able to store a non-negative
306 /// frame index in a variable that normally holds a register. isStackSlot()
307 /// returns true if Reg is in the range used for stack slots.
309 /// Note that isVirtualRegister() and isPhysicalRegister() cannot handle stack
310 /// slots, so if a variable may contains a stack slot, always check
311 /// isStackSlot() first.
313 static bool isStackSlot(unsigned Reg) {
314 return int(Reg) >= (1 << 30);
317 /// stackSlot2Index - Compute the frame index from a register value
318 /// representing a stack slot.
319 static int stackSlot2Index(unsigned Reg) {
320 assert(isStackSlot(Reg) && "Not a stack slot");
321 return int(Reg - (1u << 30));
324 /// index2StackSlot - Convert a non-negative frame index to a stack slot
326 static unsigned index2StackSlot(int FI) {
327 assert(FI >= 0 && "Cannot hold a negative frame index.");
328 return FI + (1u << 30);
331 /// isPhysicalRegister - Return true if the specified register number is in
332 /// the physical register namespace.
333 static bool isPhysicalRegister(unsigned Reg) {
334 assert(!isStackSlot(Reg) && "Not a register! Check isStackSlot() first.");
338 /// isVirtualRegister - Return true if the specified register number is in
339 /// the virtual register namespace.
340 static bool isVirtualRegister(unsigned Reg) {
341 assert(!isStackSlot(Reg) && "Not a register! Check isStackSlot() first.");
345 /// virtReg2Index - Convert a virtual register number to a 0-based index.
346 /// The first virtual register in a function will get the index 0.
347 static unsigned virtReg2Index(unsigned Reg) {
348 assert(isVirtualRegister(Reg) && "Not a virtual register");
349 return Reg & ~(1u << 31);
352 /// index2VirtReg - Convert a 0-based index to a virtual register number.
353 /// This is the inverse operation of VirtReg2IndexFunctor below.
354 static unsigned index2VirtReg(unsigned Index) {
355 return Index | (1u << 31);
358 /// getMinimalPhysRegClass - Returns the Register Class of a physical
359 /// register of the given type, picking the most sub register class of
360 /// the right type that contains this physreg.
361 const TargetRegisterClass *
362 getMinimalPhysRegClass(unsigned Reg, EVT VT = MVT::Other) const;
364 /// getAllocatableSet - Returns a bitset indexed by register number
365 /// indicating if a register is allocatable or not. If a register class is
366 /// specified, returns the subset for the class.
367 BitVector getAllocatableSet(const MachineFunction &MF,
368 const TargetRegisterClass *RC = NULL) const;
370 /// getCostPerUse - Return the additional cost of using this register instead
371 /// of other registers in its class.
372 unsigned getCostPerUse(unsigned RegNo) const {
373 return InfoDesc[RegNo].CostPerUse;
376 /// isInAllocatableClass - Return true if the register is in the allocation
377 /// of any register class.
378 bool isInAllocatableClass(unsigned RegNo) const {
379 return InfoDesc[RegNo].inAllocatableClass;
382 /// getSubRegIndexName - Return the human-readable symbolic target-specific
383 /// name for the specified SubRegIndex.
384 const char *getSubRegIndexName(unsigned SubIdx) const {
385 assert(SubIdx && "This is not a subregister index");
386 return SubRegIndexNames[SubIdx-1];
389 /// regsOverlap - Returns true if the two registers are equal or alias each
390 /// other. The registers may be virtual register.
391 bool regsOverlap(unsigned regA, unsigned regB) const {
392 if (regA == regB) return true;
393 if (isVirtualRegister(regA) || isVirtualRegister(regB))
395 for (const unsigned *regList = getOverlaps(regA)+1; *regList; ++regList) {
396 if (*regList == regB) return true;
401 /// isSubRegister - Returns true if regB is a sub-register of regA.
403 bool isSubRegister(unsigned regA, unsigned regB) const {
404 return isSuperRegister(regB, regA);
407 /// isSuperRegister - Returns true if regB is a super-register of regA.
409 bool isSuperRegister(unsigned regA, unsigned regB) const {
410 for (const unsigned *regList = getSuperRegisters(regA); *regList;++regList){
411 if (*regList == regB) return true;
416 /// getCalleeSavedRegs - Return a null-terminated list of all of the
417 /// callee saved registers on this target. The register should be in the
418 /// order of desired callee-save stack frame offset. The first register is
419 /// closed to the incoming stack pointer if stack grows down, and vice versa.
420 virtual const unsigned* getCalleeSavedRegs(const MachineFunction *MF = 0)
424 /// getReservedRegs - Returns a bitset indexed by physical register number
425 /// indicating if a register is a special register that has particular uses
426 /// and should be considered unavailable at all times, e.g. SP, RA. This is
427 /// used by register scavenger to determine what registers are free.
428 virtual BitVector getReservedRegs(const MachineFunction &MF) const = 0;
430 /// getSubReg - Returns the physical register number of sub-register "Index"
431 /// for physical register RegNo. Return zero if the sub-register does not
433 virtual unsigned getSubReg(unsigned RegNo, unsigned Index) const = 0;
435 /// getSubRegIndex - For a given register pair, return the sub-register index
436 /// if the second register is a sub-register of the first. Return zero
438 virtual unsigned getSubRegIndex(unsigned RegNo, unsigned SubRegNo) const = 0;
440 /// getMatchingSuperReg - Return a super-register of the specified register
441 /// Reg so its sub-register of index SubIdx is Reg.
442 unsigned getMatchingSuperReg(unsigned Reg, unsigned SubIdx,
443 const TargetRegisterClass *RC) const {
444 for (const unsigned *SRs = getSuperRegisters(Reg); unsigned SR = *SRs;++SRs)
445 if (Reg == getSubReg(SR, SubIdx) && RC->contains(SR))
450 /// canCombineSubRegIndices - Given a register class and a list of
451 /// subregister indices, return true if it's possible to combine the
452 /// subregister indices into one that corresponds to a larger
453 /// subregister. Return the new subregister index by reference. Note the
454 /// new index may be zero if the given subregisters can be combined to
455 /// form the whole register.
456 virtual bool canCombineSubRegIndices(const TargetRegisterClass *RC,
457 SmallVectorImpl<unsigned> &SubIndices,
458 unsigned &NewSubIdx) const {
462 /// getMatchingSuperRegClass - Return a subclass of the specified register
463 /// class A so that each register in it has a sub-register of the
464 /// specified sub-register index which is in the specified register class B.
465 virtual const TargetRegisterClass *
466 getMatchingSuperRegClass(const TargetRegisterClass *A,
467 const TargetRegisterClass *B, unsigned Idx) const {
471 /// composeSubRegIndices - Return the subregister index you get from composing
472 /// two subregister indices.
474 /// If R:a:b is the same register as R:c, then composeSubRegIndices(a, b)
475 /// returns c. Note that composeSubRegIndices does not tell you about illegal
476 /// compositions. If R does not have a subreg a, or R:a does not have a subreg
477 /// b, composeSubRegIndices doesn't tell you.
479 /// The ARM register Q0 has two D subregs dsub_0:D0 and dsub_1:D1. It also has
480 /// ssub_0:S0 - ssub_3:S3 subregs.
481 /// If you compose subreg indices dsub_1, ssub_0 you get ssub_2.
483 virtual unsigned composeSubRegIndices(unsigned a, unsigned b) const {
484 // This default implementation is correct for most targets.
488 //===--------------------------------------------------------------------===//
489 // Register Class Information
492 /// Register class iterators
494 regclass_iterator regclass_begin() const { return RegClassBegin; }
495 regclass_iterator regclass_end() const { return RegClassEnd; }
497 unsigned getNumRegClasses() const {
498 return (unsigned)(regclass_end()-regclass_begin());
501 /// getRegClass - Returns the register class associated with the enumeration
502 /// value. See class TargetOperandInfo.
503 const TargetRegisterClass *getRegClass(unsigned i) const {
504 assert(i < getNumRegClasses() && "Register Class ID out of range");
505 return RegClassBegin[i];
508 /// getPointerRegClass - Returns a TargetRegisterClass used for pointer
509 /// values. If a target supports multiple different pointer register classes,
510 /// kind specifies which one is indicated.
511 virtual const TargetRegisterClass *getPointerRegClass(unsigned Kind=0) const {
512 assert(0 && "Target didn't implement getPointerRegClass!");
513 return 0; // Must return a value in order to compile with VS 2005
516 /// getCrossCopyRegClass - Returns a legal register class to copy a register
517 /// in the specified class to or from. If it is possible to copy the register
518 /// directly without using a cross register class copy, return the specified
519 /// RC. Returns NULL if it is not possible to copy between a two registers of
520 /// the specified class.
521 virtual const TargetRegisterClass *
522 getCrossCopyRegClass(const TargetRegisterClass *RC) const {
526 /// getLargestLegalSuperClass - Returns the largest super class of RC that is
527 /// legal to use in the current sub-target and has the same spill size.
528 /// The returned register class can be used to create virtual registers which
529 /// means that all its registers can be copied and spilled.
530 virtual const TargetRegisterClass*
531 getLargestLegalSuperClass(const TargetRegisterClass *RC) const {
532 /// The default implementation is very conservative and doesn't allow the
533 /// register allocator to inflate register classes.
537 /// getRegPressureLimit - Return the register pressure "high water mark" for
538 /// the specific register class. The scheduler is in high register pressure
539 /// mode (for the specific register class) if it goes over the limit.
540 virtual unsigned getRegPressureLimit(const TargetRegisterClass *RC,
541 MachineFunction &MF) const {
545 /// getRawAllocationOrder - Returns the register allocation order for a
546 /// specified register class with a target-dependent hint. The returned list
547 /// may contain reserved registers that cannot be allocated.
549 /// Register allocators need only call this function to resolve
550 /// target-dependent hints, but it should work without hinting as well.
551 virtual ArrayRef<unsigned>
552 getRawAllocationOrder(const TargetRegisterClass *RC,
553 unsigned HintType, unsigned HintReg,
554 const MachineFunction &MF) const {
555 return RC->getRawAllocationOrder(MF);
558 /// ResolveRegAllocHint - Resolves the specified register allocation hint
559 /// to a physical register. Returns the physical register if it is successful.
560 virtual unsigned ResolveRegAllocHint(unsigned Type, unsigned Reg,
561 const MachineFunction &MF) const {
562 if (Type == 0 && Reg && isPhysicalRegister(Reg))
567 /// avoidWriteAfterWrite - Return true if the register allocator should avoid
568 /// writing a register from RC in two consecutive instructions.
569 /// This can avoid pipeline stalls on certain architectures.
570 /// It does cause increased register pressure, though.
571 virtual bool avoidWriteAfterWrite(const TargetRegisterClass *RC) const {
575 /// UpdateRegAllocHint - A callback to allow target a chance to update
576 /// register allocation hints when a register is "changed" (e.g. coalesced)
577 /// to another register. e.g. On ARM, some virtual registers should target
578 /// register pairs, if one of pair is coalesced to another register, the
579 /// allocation hint of the other half of the pair should be changed to point
580 /// to the new register.
581 virtual void UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
582 MachineFunction &MF) const {
586 /// requiresRegisterScavenging - returns true if the target requires (and can
587 /// make use of) the register scavenger.
588 virtual bool requiresRegisterScavenging(const MachineFunction &MF) const {
592 /// useFPForScavengingIndex - returns true if the target wants to use
593 /// frame pointer based accesses to spill to the scavenger emergency spill
595 virtual bool useFPForScavengingIndex(const MachineFunction &MF) const {
599 /// requiresFrameIndexScavenging - returns true if the target requires post
600 /// PEI scavenging of registers for materializing frame index constants.
601 virtual bool requiresFrameIndexScavenging(const MachineFunction &MF) const {
605 /// requiresVirtualBaseRegisters - Returns true if the target wants the
606 /// LocalStackAllocation pass to be run and virtual base registers
607 /// used for more efficient stack access.
608 virtual bool requiresVirtualBaseRegisters(const MachineFunction &MF) const {
612 /// hasReservedSpillSlot - Return true if target has reserved a spill slot in
613 /// the stack frame of the given function for the specified register. e.g. On
614 /// x86, if the frame register is required, the first fixed stack object is
615 /// reserved as its spill slot. This tells PEI not to create a new stack frame
616 /// object for the given register. It should be called only after
617 /// processFunctionBeforeCalleeSavedScan().
618 virtual bool hasReservedSpillSlot(const MachineFunction &MF, unsigned Reg,
619 int &FrameIdx) const {
623 /// needsStackRealignment - true if storage within the function requires the
624 /// stack pointer to be aligned more than the normal calling convention calls
626 virtual bool needsStackRealignment(const MachineFunction &MF) const {
630 /// getFrameIndexInstrOffset - Get the offset from the referenced frame
631 /// index in the instruction, if there is one.
632 virtual int64_t getFrameIndexInstrOffset(const MachineInstr *MI,
637 /// needsFrameBaseReg - Returns true if the instruction's frame index
638 /// reference would be better served by a base register other than FP
639 /// or SP. Used by LocalStackFrameAllocation to determine which frame index
640 /// references it should create new base registers for.
641 virtual bool needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
645 /// materializeFrameBaseRegister - Insert defining instruction(s) for
646 /// BaseReg to be a pointer to FrameIdx before insertion point I.
647 virtual void materializeFrameBaseRegister(MachineBasicBlock *MBB,
648 unsigned BaseReg, int FrameIdx,
649 int64_t Offset) const {
650 assert(0 && "materializeFrameBaseRegister does not exist on this target");
653 /// resolveFrameIndex - Resolve a frame index operand of an instruction
654 /// to reference the indicated base register plus offset instead.
655 virtual void resolveFrameIndex(MachineBasicBlock::iterator I,
656 unsigned BaseReg, int64_t Offset) const {
657 assert(0 && "resolveFrameIndex does not exist on this target");
660 /// isFrameOffsetLegal - Determine whether a given offset immediate is
661 /// encodable to resolve a frame index.
662 virtual bool isFrameOffsetLegal(const MachineInstr *MI,
663 int64_t Offset) const {
664 assert(0 && "isFrameOffsetLegal does not exist on this target");
665 return false; // Must return a value in order to compile with VS 2005
668 /// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the
669 /// frame setup/destroy instructions if they exist (-1 otherwise). Some
670 /// targets use pseudo instructions in order to abstract away the difference
671 /// between operating with a frame pointer and operating without, through the
672 /// use of these two instructions.
674 int getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; }
675 int getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; }
677 /// eliminateCallFramePseudoInstr - This method is called during prolog/epilog
678 /// code insertion to eliminate call frame setup and destroy pseudo
679 /// instructions (but only if the Target is using them). It is responsible
680 /// for eliminating these instructions, replacing them with concrete
681 /// instructions. This method need only be implemented if using call frame
682 /// setup/destroy pseudo instructions.
685 eliminateCallFramePseudoInstr(MachineFunction &MF,
686 MachineBasicBlock &MBB,
687 MachineBasicBlock::iterator MI) const {
688 assert(getCallFrameSetupOpcode()== -1 && getCallFrameDestroyOpcode()== -1 &&
689 "eliminateCallFramePseudoInstr must be implemented if using"
690 " call frame setup/destroy pseudo instructions!");
691 assert(0 && "Call Frame Pseudo Instructions do not exist on this target!");
695 /// saveScavengerRegister - Spill the register so it can be used by the
696 /// register scavenger. Return true if the register was spilled, false
697 /// otherwise. If this function does not spill the register, the scavenger
698 /// will instead spill it to the emergency spill slot.
700 virtual bool saveScavengerRegister(MachineBasicBlock &MBB,
701 MachineBasicBlock::iterator I,
702 MachineBasicBlock::iterator &UseMI,
703 const TargetRegisterClass *RC,
704 unsigned Reg) const {
708 /// eliminateFrameIndex - This method must be overriden to eliminate abstract
709 /// frame indices from instructions which may use them. The instruction
710 /// referenced by the iterator contains an MO_FrameIndex operand which must be
711 /// eliminated by this method. This method may modify or replace the
712 /// specified instruction, as long as it keeps the iterator pointing at the
713 /// finished product. SPAdj is the SP adjustment due to call frame setup
715 virtual void eliminateFrameIndex(MachineBasicBlock::iterator MI,
716 int SPAdj, RegScavenger *RS=NULL) const = 0;
718 //===--------------------------------------------------------------------===//
719 /// Debug information queries.
721 /// getDwarfRegNum - Map a target register to an equivalent dwarf register
722 /// number. Returns -1 if there is no equivalent value. The second
723 /// parameter allows targets to use different numberings for EH info and
725 virtual int getDwarfRegNum(unsigned RegNum, bool isEH) const = 0;
727 virtual int getLLVMRegNum(unsigned RegNum, bool isEH) const = 0;
729 /// getFrameRegister - This method should return the register used as a base
730 /// for values allocated in the current stack frame.
731 virtual unsigned getFrameRegister(const MachineFunction &MF) const = 0;
733 /// getRARegister - This method should return the register where the return
734 /// address can be found.
735 virtual unsigned getRARegister() const = 0;
737 /// getSEHRegNum - Map a target register to an equivalent SEH register
738 /// number. Returns -1 if there is no equivalent value.
739 virtual int getSEHRegNum(unsigned i) const {
745 // This is useful when building IndexedMaps keyed on virtual registers
746 struct VirtReg2IndexFunctor : public std::unary_function<unsigned, unsigned> {
747 unsigned operator()(unsigned Reg) const {
748 return TargetRegisterInfo::virtReg2Index(Reg);
752 /// getCommonSubClass - find the largest common subclass of A and B. Return NULL
753 /// if there is no common subclass.
754 const TargetRegisterClass *getCommonSubClass(const TargetRegisterClass *A,
755 const TargetRegisterClass *B);
757 /// PrintReg - Helper class for printing registers on a raw_ostream.
758 /// Prints virtual and physical registers with or without a TRI instance.
761 /// %noreg - NoRegister
762 /// %vreg5 - a virtual register.
763 /// %vreg5:sub_8bit - a virtual register with sub-register index (with TRI).
764 /// %EAX - a physical register
765 /// %physreg17 - a physical register when no TRI instance given.
767 /// Usage: OS << PrintReg(Reg, TRI) << '\n';
770 const TargetRegisterInfo *TRI;
774 PrintReg(unsigned reg, const TargetRegisterInfo *tri = 0, unsigned subidx = 0)
775 : TRI(tri), Reg(reg), SubIdx(subidx) {}
776 void print(raw_ostream&) const;
779 static inline raw_ostream &operator<<(raw_ostream &OS, const PrintReg &PR) {
784 } // End llvm namespace