1 //===-- llvm/CodeGen/MachineRegisterInfo.h ----------------------*- 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 defines the MachineRegisterInfo class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CODEGEN_MACHINEREGISTERINFO_H
15 #define LLVM_CODEGEN_MACHINEREGISTERINFO_H
17 #include "llvm/ADT/BitVector.h"
18 #include "llvm/ADT/IndexedMap.h"
19 #include "llvm/ADT/iterator_range.h"
20 #include "llvm/CodeGen/MachineFunction.h"
21 #include "llvm/CodeGen/MachineInstrBundle.h"
22 #include "llvm/Target/TargetRegisterInfo.h"
23 #include "llvm/Target/TargetSubtargetInfo.h"
29 /// MachineRegisterInfo - Keep track of information for virtual and physical
30 /// registers, including vreg register classes, use/def chains for registers,
32 class MachineRegisterInfo {
35 virtual void anchor();
37 virtual void MRI_NoteNewVirtualRegister(unsigned Reg) = 0;
39 virtual ~Delegate() {}
43 const MachineFunction *MF;
44 Delegate *TheDelegate;
46 /// IsSSA - True when the machine function is in SSA form and virtual
47 /// registers have a single def.
50 /// TracksLiveness - True while register liveness is being tracked accurately.
51 /// Basic block live-in lists, kill flags, and implicit defs may not be
52 /// accurate when after this flag is cleared.
55 /// True if subregister liveness is tracked.
56 bool TracksSubRegLiveness;
58 /// VRegInfo - Information we keep for each virtual register.
60 /// Each element in this list contains the register class of the vreg and the
61 /// start of the use/def list for the register.
62 IndexedMap<std::pair<const TargetRegisterClass*, MachineOperand*>,
63 VirtReg2IndexFunctor> VRegInfo;
65 /// RegAllocHints - This vector records register allocation hints for virtual
66 /// registers. For each virtual register, it keeps a register and hint type
67 /// pair making up the allocation hint. Hint type is target specific except
68 /// for the value 0 which means the second value of the pair is the preferred
69 /// register for allocation. For example, if the hint is <0, 1024>, it means
70 /// the allocator should prefer the physical register allocated to the virtual
71 /// register of the hint.
72 IndexedMap<std::pair<unsigned, unsigned>, VirtReg2IndexFunctor> RegAllocHints;
74 /// PhysRegUseDefLists - This is an array of the head of the use/def list for
75 /// physical registers.
76 std::vector<MachineOperand *> PhysRegUseDefLists;
78 /// getRegUseDefListHead - Return the head pointer for the register use/def
79 /// list for the specified virtual or physical register.
80 MachineOperand *&getRegUseDefListHead(unsigned RegNo) {
81 if (TargetRegisterInfo::isVirtualRegister(RegNo))
82 return VRegInfo[RegNo].second;
83 return PhysRegUseDefLists[RegNo];
86 MachineOperand *getRegUseDefListHead(unsigned RegNo) const {
87 if (TargetRegisterInfo::isVirtualRegister(RegNo))
88 return VRegInfo[RegNo].second;
89 return PhysRegUseDefLists[RegNo];
92 /// Get the next element in the use-def chain.
93 static MachineOperand *getNextOperandForReg(const MachineOperand *MO) {
94 assert(MO && MO->isReg() && "This is not a register operand!");
95 return MO->Contents.Reg.Next;
98 /// UsedRegUnits - This is a bit vector that is computed and set by the
99 /// register allocator, and must be kept up to date by passes that run after
100 /// register allocation (though most don't modify this). This is used
101 /// so that the code generator knows which callee save registers to save and
102 /// for other target specific uses.
103 /// This vector has bits set for register units that are modified in the
104 /// current function. It doesn't include registers clobbered by function
105 /// calls with register mask operands.
106 BitVector UsedRegUnits;
108 /// UsedPhysRegMask - Additional used physregs including aliases.
109 /// This bit vector represents all the registers clobbered by function calls.
110 /// It can model things that UsedRegUnits can't, such as function calls that
111 /// clobber ymm7 but preserve the low half in xmm7.
112 BitVector UsedPhysRegMask;
114 /// ReservedRegs - This is a bit vector of reserved registers. The target
115 /// may change its mind about which registers should be reserved. This
116 /// vector is the frozen set of reserved registers when register allocation
118 BitVector ReservedRegs;
120 /// Keep track of the physical registers that are live in to the function.
121 /// Live in values are typically arguments in registers. LiveIn values are
122 /// allowed to have virtual registers associated with them, stored in the
124 std::vector<std::pair<unsigned, unsigned> > LiveIns;
126 MachineRegisterInfo(const MachineRegisterInfo&) = delete;
127 void operator=(const MachineRegisterInfo&) = delete;
129 explicit MachineRegisterInfo(const MachineFunction *MF);
131 const TargetRegisterInfo *getTargetRegisterInfo() const {
132 return MF->getSubtarget().getRegisterInfo();
135 void resetDelegate(Delegate *delegate) {
136 // Ensure another delegate does not take over unless the current
137 // delegate first unattaches itself. If we ever need to multicast
138 // notifications, we will need to change to using a list.
139 assert(TheDelegate == delegate &&
140 "Only the current delegate can perform reset!");
141 TheDelegate = nullptr;
144 void setDelegate(Delegate *delegate) {
145 assert(delegate && !TheDelegate &&
146 "Attempted to set delegate to null, or to change it without "
147 "first resetting it!");
149 TheDelegate = delegate;
152 //===--------------------------------------------------------------------===//
154 //===--------------------------------------------------------------------===//
156 // isSSA - Returns true when the machine function is in SSA form. Early
157 // passes require the machine function to be in SSA form where every virtual
158 // register has a single defining instruction.
160 // The TwoAddressInstructionPass and PHIElimination passes take the machine
161 // function out of SSA form when they introduce multiple defs per virtual
163 bool isSSA() const { return IsSSA; }
165 // leaveSSA - Indicates that the machine function is no longer in SSA form.
166 void leaveSSA() { IsSSA = false; }
168 /// tracksLiveness - Returns true when tracking register liveness accurately.
170 /// While this flag is true, register liveness information in basic block
171 /// live-in lists and machine instruction operands is accurate. This means it
172 /// can be used to change the code in ways that affect the values in
173 /// registers, for example by the register scavenger.
175 /// When this flag is false, liveness is no longer reliable.
176 bool tracksLiveness() const { return TracksLiveness; }
178 /// invalidateLiveness - Indicates that register liveness is no longer being
179 /// tracked accurately.
181 /// This should be called by late passes that invalidate the liveness
183 void invalidateLiveness() { TracksLiveness = false; }
185 /// Returns true if liveness for register class @p RC should be tracked at
186 /// the subregister level.
187 bool shouldTrackSubRegLiveness(const TargetRegisterClass &RC) const {
188 return subRegLivenessEnabled() && RC.HasDisjunctSubRegs;
190 bool shouldTrackSubRegLiveness(unsigned VReg) const {
191 assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Must pass a VReg");
192 return shouldTrackSubRegLiveness(*getRegClass(VReg));
194 bool subRegLivenessEnabled() const {
195 return TracksSubRegLiveness;
198 void enableSubRegLiveness(bool Enable = true) {
199 TracksSubRegLiveness = Enable;
202 //===--------------------------------------------------------------------===//
204 //===--------------------------------------------------------------------===//
206 // Strictly for use by MachineInstr.cpp.
207 void addRegOperandToUseList(MachineOperand *MO);
209 // Strictly for use by MachineInstr.cpp.
210 void removeRegOperandFromUseList(MachineOperand *MO);
212 // Strictly for use by MachineInstr.cpp.
213 void moveOperands(MachineOperand *Dst, MachineOperand *Src, unsigned NumOps);
215 /// Verify the sanity of the use list for Reg.
216 void verifyUseList(unsigned Reg) const;
218 /// Verify the use list of all registers.
219 void verifyUseLists() const;
221 /// reg_begin/reg_end - Provide iteration support to walk over all definitions
222 /// and uses of a register within the MachineFunction that corresponds to this
223 /// MachineRegisterInfo object.
224 template<bool Uses, bool Defs, bool SkipDebug,
225 bool ByOperand, bool ByInstr, bool ByBundle>
226 class defusechain_iterator;
227 template<bool Uses, bool Defs, bool SkipDebug,
228 bool ByOperand, bool ByInstr, bool ByBundle>
229 class defusechain_instr_iterator;
231 // Make it a friend so it can access getNextOperandForReg().
232 template<bool, bool, bool, bool, bool, bool>
233 friend class defusechain_iterator;
234 template<bool, bool, bool, bool, bool, bool>
235 friend class defusechain_instr_iterator;
239 /// reg_iterator/reg_begin/reg_end - Walk all defs and uses of the specified
241 typedef defusechain_iterator<true,true,false,true,false,false>
243 reg_iterator reg_begin(unsigned RegNo) const {
244 return reg_iterator(getRegUseDefListHead(RegNo));
246 static reg_iterator reg_end() { return reg_iterator(nullptr); }
248 inline iterator_range<reg_iterator> reg_operands(unsigned Reg) const {
249 return iterator_range<reg_iterator>(reg_begin(Reg), reg_end());
252 /// reg_instr_iterator/reg_instr_begin/reg_instr_end - Walk all defs and uses
253 /// of the specified register, stepping by MachineInstr.
254 typedef defusechain_instr_iterator<true,true,false,false,true,false>
256 reg_instr_iterator reg_instr_begin(unsigned RegNo) const {
257 return reg_instr_iterator(getRegUseDefListHead(RegNo));
259 static reg_instr_iterator reg_instr_end() {
260 return reg_instr_iterator(nullptr);
263 inline iterator_range<reg_instr_iterator>
264 reg_instructions(unsigned Reg) const {
265 return iterator_range<reg_instr_iterator>(reg_instr_begin(Reg),
269 /// reg_bundle_iterator/reg_bundle_begin/reg_bundle_end - Walk all defs and uses
270 /// of the specified register, stepping by bundle.
271 typedef defusechain_instr_iterator<true,true,false,false,false,true>
273 reg_bundle_iterator reg_bundle_begin(unsigned RegNo) const {
274 return reg_bundle_iterator(getRegUseDefListHead(RegNo));
276 static reg_bundle_iterator reg_bundle_end() {
277 return reg_bundle_iterator(nullptr);
280 inline iterator_range<reg_bundle_iterator> reg_bundles(unsigned Reg) const {
281 return iterator_range<reg_bundle_iterator>(reg_bundle_begin(Reg),
285 /// reg_empty - Return true if there are no instructions using or defining the
286 /// specified register (it may be live-in).
287 bool reg_empty(unsigned RegNo) const { return reg_begin(RegNo) == reg_end(); }
289 /// reg_nodbg_iterator/reg_nodbg_begin/reg_nodbg_end - Walk all defs and uses
290 /// of the specified register, skipping those marked as Debug.
291 typedef defusechain_iterator<true,true,true,true,false,false>
293 reg_nodbg_iterator reg_nodbg_begin(unsigned RegNo) const {
294 return reg_nodbg_iterator(getRegUseDefListHead(RegNo));
296 static reg_nodbg_iterator reg_nodbg_end() {
297 return reg_nodbg_iterator(nullptr);
300 inline iterator_range<reg_nodbg_iterator>
301 reg_nodbg_operands(unsigned Reg) const {
302 return iterator_range<reg_nodbg_iterator>(reg_nodbg_begin(Reg),
306 /// reg_instr_nodbg_iterator/reg_instr_nodbg_begin/reg_instr_nodbg_end - Walk
307 /// all defs and uses of the specified register, stepping by MachineInstr,
308 /// skipping those marked as Debug.
309 typedef defusechain_instr_iterator<true,true,true,false,true,false>
310 reg_instr_nodbg_iterator;
311 reg_instr_nodbg_iterator reg_instr_nodbg_begin(unsigned RegNo) const {
312 return reg_instr_nodbg_iterator(getRegUseDefListHead(RegNo));
314 static reg_instr_nodbg_iterator reg_instr_nodbg_end() {
315 return reg_instr_nodbg_iterator(nullptr);
318 inline iterator_range<reg_instr_nodbg_iterator>
319 reg_nodbg_instructions(unsigned Reg) const {
320 return iterator_range<reg_instr_nodbg_iterator>(reg_instr_nodbg_begin(Reg),
321 reg_instr_nodbg_end());
324 /// reg_bundle_nodbg_iterator/reg_bundle_nodbg_begin/reg_bundle_nodbg_end - Walk
325 /// all defs and uses of the specified register, stepping by bundle,
326 /// skipping those marked as Debug.
327 typedef defusechain_instr_iterator<true,true,true,false,false,true>
328 reg_bundle_nodbg_iterator;
329 reg_bundle_nodbg_iterator reg_bundle_nodbg_begin(unsigned RegNo) const {
330 return reg_bundle_nodbg_iterator(getRegUseDefListHead(RegNo));
332 static reg_bundle_nodbg_iterator reg_bundle_nodbg_end() {
333 return reg_bundle_nodbg_iterator(nullptr);
336 inline iterator_range<reg_bundle_nodbg_iterator>
337 reg_nodbg_bundles(unsigned Reg) const {
338 return iterator_range<reg_bundle_nodbg_iterator>(reg_bundle_nodbg_begin(Reg),
339 reg_bundle_nodbg_end());
342 /// reg_nodbg_empty - Return true if the only instructions using or defining
343 /// Reg are Debug instructions.
344 bool reg_nodbg_empty(unsigned RegNo) const {
345 return reg_nodbg_begin(RegNo) == reg_nodbg_end();
348 /// def_iterator/def_begin/def_end - Walk all defs of the specified register.
349 typedef defusechain_iterator<false,true,false,true,false,false>
351 def_iterator def_begin(unsigned RegNo) const {
352 return def_iterator(getRegUseDefListHead(RegNo));
354 static def_iterator def_end() { return def_iterator(nullptr); }
356 inline iterator_range<def_iterator> def_operands(unsigned Reg) const {
357 return iterator_range<def_iterator>(def_begin(Reg), def_end());
360 /// def_instr_iterator/def_instr_begin/def_instr_end - Walk all defs of the
361 /// specified register, stepping by MachineInst.
362 typedef defusechain_instr_iterator<false,true,false,false,true,false>
364 def_instr_iterator def_instr_begin(unsigned RegNo) const {
365 return def_instr_iterator(getRegUseDefListHead(RegNo));
367 static def_instr_iterator def_instr_end() {
368 return def_instr_iterator(nullptr);
371 inline iterator_range<def_instr_iterator>
372 def_instructions(unsigned Reg) const {
373 return iterator_range<def_instr_iterator>(def_instr_begin(Reg),
377 /// def_bundle_iterator/def_bundle_begin/def_bundle_end - Walk all defs of the
378 /// specified register, stepping by bundle.
379 typedef defusechain_instr_iterator<false,true,false,false,false,true>
381 def_bundle_iterator def_bundle_begin(unsigned RegNo) const {
382 return def_bundle_iterator(getRegUseDefListHead(RegNo));
384 static def_bundle_iterator def_bundle_end() {
385 return def_bundle_iterator(nullptr);
388 inline iterator_range<def_bundle_iterator> def_bundles(unsigned Reg) const {
389 return iterator_range<def_bundle_iterator>(def_bundle_begin(Reg),
393 /// def_empty - Return true if there are no instructions defining the
394 /// specified register (it may be live-in).
395 bool def_empty(unsigned RegNo) const { return def_begin(RegNo) == def_end(); }
397 /// hasOneDef - Return true if there is exactly one instruction defining the
398 /// specified register.
399 bool hasOneDef(unsigned RegNo) const {
400 def_iterator DI = def_begin(RegNo);
403 return ++DI == def_end();
406 /// use_iterator/use_begin/use_end - Walk all uses of the specified register.
407 typedef defusechain_iterator<true,false,false,true,false,false>
409 use_iterator use_begin(unsigned RegNo) const {
410 return use_iterator(getRegUseDefListHead(RegNo));
412 static use_iterator use_end() { return use_iterator(nullptr); }
414 inline iterator_range<use_iterator> use_operands(unsigned Reg) const {
415 return iterator_range<use_iterator>(use_begin(Reg), use_end());
418 /// use_instr_iterator/use_instr_begin/use_instr_end - Walk all uses of the
419 /// specified register, stepping by MachineInstr.
420 typedef defusechain_instr_iterator<true,false,false,false,true,false>
422 use_instr_iterator use_instr_begin(unsigned RegNo) const {
423 return use_instr_iterator(getRegUseDefListHead(RegNo));
425 static use_instr_iterator use_instr_end() {
426 return use_instr_iterator(nullptr);
429 inline iterator_range<use_instr_iterator>
430 use_instructions(unsigned Reg) const {
431 return iterator_range<use_instr_iterator>(use_instr_begin(Reg),
435 /// use_bundle_iterator/use_bundle_begin/use_bundle_end - Walk all uses of the
436 /// specified register, stepping by bundle.
437 typedef defusechain_instr_iterator<true,false,false,false,false,true>
439 use_bundle_iterator use_bundle_begin(unsigned RegNo) const {
440 return use_bundle_iterator(getRegUseDefListHead(RegNo));
442 static use_bundle_iterator use_bundle_end() {
443 return use_bundle_iterator(nullptr);
446 inline iterator_range<use_bundle_iterator> use_bundles(unsigned Reg) const {
447 return iterator_range<use_bundle_iterator>(use_bundle_begin(Reg),
451 /// use_empty - Return true if there are no instructions using the specified
453 bool use_empty(unsigned RegNo) const { return use_begin(RegNo) == use_end(); }
455 /// hasOneUse - Return true if there is exactly one instruction using the
456 /// specified register.
457 bool hasOneUse(unsigned RegNo) const {
458 use_iterator UI = use_begin(RegNo);
461 return ++UI == use_end();
464 /// use_nodbg_iterator/use_nodbg_begin/use_nodbg_end - Walk all uses of the
465 /// specified register, skipping those marked as Debug.
466 typedef defusechain_iterator<true,false,true,true,false,false>
468 use_nodbg_iterator use_nodbg_begin(unsigned RegNo) const {
469 return use_nodbg_iterator(getRegUseDefListHead(RegNo));
471 static use_nodbg_iterator use_nodbg_end() {
472 return use_nodbg_iterator(nullptr);
475 inline iterator_range<use_nodbg_iterator>
476 use_nodbg_operands(unsigned Reg) const {
477 return iterator_range<use_nodbg_iterator>(use_nodbg_begin(Reg),
481 /// use_instr_nodbg_iterator/use_instr_nodbg_begin/use_instr_nodbg_end - Walk
482 /// all uses of the specified register, stepping by MachineInstr, skipping
483 /// those marked as Debug.
484 typedef defusechain_instr_iterator<true,false,true,false,true,false>
485 use_instr_nodbg_iterator;
486 use_instr_nodbg_iterator use_instr_nodbg_begin(unsigned RegNo) const {
487 return use_instr_nodbg_iterator(getRegUseDefListHead(RegNo));
489 static use_instr_nodbg_iterator use_instr_nodbg_end() {
490 return use_instr_nodbg_iterator(nullptr);
493 inline iterator_range<use_instr_nodbg_iterator>
494 use_nodbg_instructions(unsigned Reg) const {
495 return iterator_range<use_instr_nodbg_iterator>(use_instr_nodbg_begin(Reg),
496 use_instr_nodbg_end());
499 /// use_bundle_nodbg_iterator/use_bundle_nodbg_begin/use_bundle_nodbg_end - Walk
500 /// all uses of the specified register, stepping by bundle, skipping
501 /// those marked as Debug.
502 typedef defusechain_instr_iterator<true,false,true,false,false,true>
503 use_bundle_nodbg_iterator;
504 use_bundle_nodbg_iterator use_bundle_nodbg_begin(unsigned RegNo) const {
505 return use_bundle_nodbg_iterator(getRegUseDefListHead(RegNo));
507 static use_bundle_nodbg_iterator use_bundle_nodbg_end() {
508 return use_bundle_nodbg_iterator(nullptr);
511 inline iterator_range<use_bundle_nodbg_iterator>
512 use_nodbg_bundles(unsigned Reg) const {
513 return iterator_range<use_bundle_nodbg_iterator>(use_bundle_nodbg_begin(Reg),
514 use_bundle_nodbg_end());
517 /// use_nodbg_empty - Return true if there are no non-Debug instructions
518 /// using the specified register.
519 bool use_nodbg_empty(unsigned RegNo) const {
520 return use_nodbg_begin(RegNo) == use_nodbg_end();
523 /// hasOneNonDBGUse - Return true if there is exactly one non-Debug
524 /// instruction using the specified register.
525 bool hasOneNonDBGUse(unsigned RegNo) const;
527 /// replaceRegWith - Replace all instances of FromReg with ToReg in the
528 /// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
529 /// except that it also changes any definitions of the register as well.
531 /// Note that it is usually necessary to first constrain ToReg's register
532 /// class to match the FromReg constraints using:
534 /// constrainRegClass(ToReg, getRegClass(FromReg))
536 /// That function will return NULL if the virtual registers have incompatible
539 /// Note that if ToReg is a physical register the function will replace and
540 /// apply sub registers to ToReg in order to obtain a final/proper physical
542 void replaceRegWith(unsigned FromReg, unsigned ToReg);
544 /// getVRegDef - Return the machine instr that defines the specified virtual
545 /// register or null if none is found. This assumes that the code is in SSA
546 /// form, so there should only be one definition.
547 MachineInstr *getVRegDef(unsigned Reg) const;
549 /// getUniqueVRegDef - Return the unique machine instr that defines the
550 /// specified virtual register or null if none is found. If there are
551 /// multiple definitions or no definition, return null.
552 MachineInstr *getUniqueVRegDef(unsigned Reg) const;
554 /// clearKillFlags - Iterate over all the uses of the given register and
555 /// clear the kill flag from the MachineOperand. This function is used by
556 /// optimization passes which extend register lifetimes and need only
557 /// preserve conservative kill flag information.
558 void clearKillFlags(unsigned Reg) const;
561 void dumpUses(unsigned RegNo) const;
564 /// isConstantPhysReg - Returns true if PhysReg is unallocatable and constant
565 /// throughout the function. It is safe to move instructions that read such
567 bool isConstantPhysReg(unsigned PhysReg, const MachineFunction &MF) const;
569 /// Get an iterator over the pressure sets affected by the given physical or
570 /// virtual register. If RegUnit is physical, it must be a register unit (from
571 /// MCRegUnitIterator).
572 PSetIterator getPressureSets(unsigned RegUnit) const;
574 //===--------------------------------------------------------------------===//
575 // Virtual Register Info
576 //===--------------------------------------------------------------------===//
578 /// getRegClass - Return the register class of the specified virtual register.
580 const TargetRegisterClass *getRegClass(unsigned Reg) const {
581 return VRegInfo[Reg].first;
584 /// setRegClass - Set the register class of the specified virtual register.
586 void setRegClass(unsigned Reg, const TargetRegisterClass *RC);
588 /// constrainRegClass - Constrain the register class of the specified virtual
589 /// register to be a common subclass of RC and the current register class,
590 /// but only if the new class has at least MinNumRegs registers. Return the
591 /// new register class, or NULL if no such class exists.
592 /// This should only be used when the constraint is known to be trivial, like
593 /// GR32 -> GR32_NOSP. Beware of increasing register pressure.
595 const TargetRegisterClass *constrainRegClass(unsigned Reg,
596 const TargetRegisterClass *RC,
597 unsigned MinNumRegs = 0);
599 /// recomputeRegClass - Try to find a legal super-class of Reg's register
600 /// class that still satisfies the constraints from the instructions using
601 /// Reg. Returns true if Reg was upgraded.
603 /// This method can be used after constraints have been removed from a
604 /// virtual register, for example after removing instructions or splitting
607 bool recomputeRegClass(unsigned Reg);
609 /// createVirtualRegister - Create and return a new virtual register in the
610 /// function with the specified register class.
612 unsigned createVirtualRegister(const TargetRegisterClass *RegClass);
614 /// getNumVirtRegs - Return the number of virtual registers created.
616 unsigned getNumVirtRegs() const { return VRegInfo.size(); }
618 /// clearVirtRegs - Remove all virtual registers (after physreg assignment).
619 void clearVirtRegs();
621 /// setRegAllocationHint - Specify a register allocation hint for the
622 /// specified virtual register.
623 void setRegAllocationHint(unsigned VReg, unsigned Type, unsigned PrefReg) {
624 assert(TargetRegisterInfo::isVirtualRegister(VReg));
625 RegAllocHints[VReg].first = Type;
626 RegAllocHints[VReg].second = PrefReg;
629 /// getRegAllocationHint - Return the register allocation hint for the
630 /// specified virtual register.
631 std::pair<unsigned, unsigned>
632 getRegAllocationHint(unsigned VReg) const {
633 assert(TargetRegisterInfo::isVirtualRegister(VReg));
634 return RegAllocHints[VReg];
637 /// getSimpleHint - Return the preferred register allocation hint, or 0 if a
638 /// standard simple hint (Type == 0) is not set.
639 unsigned getSimpleHint(unsigned VReg) const {
640 assert(TargetRegisterInfo::isVirtualRegister(VReg));
641 std::pair<unsigned, unsigned> Hint = getRegAllocationHint(VReg);
642 return Hint.first ? 0 : Hint.second;
645 /// markUsesInDebugValueAsUndef - Mark every DBG_VALUE referencing the
646 /// specified register as undefined which causes the DBG_VALUE to be
647 /// deleted during LiveDebugVariables analysis.
648 void markUsesInDebugValueAsUndef(unsigned Reg) const;
650 /// Return true if the specified register is modified in this function.
651 /// This checks that no defining machine operands exist for the register or
652 /// any of its aliases. Definitions found on functions marked noreturn are
654 bool isPhysRegModified(unsigned PhysReg) const;
656 //===--------------------------------------------------------------------===//
657 // Physical Register Use Info
658 //===--------------------------------------------------------------------===//
660 /// isPhysRegUsed - Return true if the specified register is used in this
661 /// function. Also check for clobbered aliases and registers clobbered by
662 /// function calls with register mask operands.
664 /// This only works after register allocation.
665 bool isPhysRegUsed(unsigned Reg) const {
666 if (UsedPhysRegMask.test(Reg))
668 for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
669 Units.isValid(); ++Units)
670 if (UsedRegUnits.test(*Units))
675 /// Mark the specified register unit as used in this function.
676 /// This should only be called during and after register allocation.
677 void setRegUnitUsed(unsigned RegUnit) {
678 UsedRegUnits.set(RegUnit);
681 /// setPhysRegUsed - Mark the specified register used in this function.
682 /// This should only be called during and after register allocation.
683 void setPhysRegUsed(unsigned Reg) {
684 for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
685 Units.isValid(); ++Units)
686 UsedRegUnits.set(*Units);
689 /// addPhysRegsUsedFromRegMask - Mark any registers not in RegMask as used.
690 /// This corresponds to the bit mask attached to register mask operands.
691 void addPhysRegsUsedFromRegMask(const uint32_t *RegMask) {
692 UsedPhysRegMask.setBitsNotInMask(RegMask);
695 /// setPhysRegUnused - Mark the specified register unused in this function.
696 /// This should only be called during and after register allocation.
697 void setPhysRegUnused(unsigned Reg) {
698 UsedPhysRegMask.reset(Reg);
699 for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
700 Units.isValid(); ++Units)
701 UsedRegUnits.reset(*Units);
705 //===--------------------------------------------------------------------===//
706 // Reserved Register Info
707 //===--------------------------------------------------------------------===//
709 // The set of reserved registers must be invariant during register
710 // allocation. For example, the target cannot suddenly decide it needs a
711 // frame pointer when the register allocator has already used the frame
712 // pointer register for something else.
714 // These methods can be used by target hooks like hasFP() to avoid changing
715 // the reserved register set during register allocation.
717 /// freezeReservedRegs - Called by the register allocator to freeze the set
718 /// of reserved registers before allocation begins.
719 void freezeReservedRegs(const MachineFunction&);
721 /// reservedRegsFrozen - Returns true after freezeReservedRegs() was called
722 /// to ensure the set of reserved registers stays constant.
723 bool reservedRegsFrozen() const {
724 return !ReservedRegs.empty();
727 /// canReserveReg - Returns true if PhysReg can be used as a reserved
728 /// register. Any register can be reserved before freezeReservedRegs() is
730 bool canReserveReg(unsigned PhysReg) const {
731 return !reservedRegsFrozen() || ReservedRegs.test(PhysReg);
734 /// getReservedRegs - Returns a reference to the frozen set of reserved
735 /// registers. This method should always be preferred to calling
736 /// TRI::getReservedRegs() when possible.
737 const BitVector &getReservedRegs() const {
738 assert(reservedRegsFrozen() &&
739 "Reserved registers haven't been frozen yet. "
740 "Use TRI::getReservedRegs().");
744 /// isReserved - Returns true when PhysReg is a reserved register.
746 /// Reserved registers may belong to an allocatable register class, but the
747 /// target has explicitly requested that they are not used.
749 bool isReserved(unsigned PhysReg) const {
750 return getReservedRegs().test(PhysReg);
753 /// isAllocatable - Returns true when PhysReg belongs to an allocatable
754 /// register class and it hasn't been reserved.
756 /// Allocatable registers may show up in the allocation order of some virtual
757 /// register, so a register allocator needs to track its liveness and
759 bool isAllocatable(unsigned PhysReg) const {
760 return getTargetRegisterInfo()->isInAllocatableClass(PhysReg) &&
761 !isReserved(PhysReg);
764 //===--------------------------------------------------------------------===//
766 //===--------------------------------------------------------------------===//
768 /// addLiveIn - Add the specified register as a live-in. Note that it
769 /// is an error to add the same register to the same set more than once.
770 void addLiveIn(unsigned Reg, unsigned vreg = 0) {
771 LiveIns.push_back(std::make_pair(Reg, vreg));
774 // Iteration support for the live-ins set. It's kept in sorted order
775 // by register number.
776 typedef std::vector<std::pair<unsigned,unsigned> >::const_iterator
778 livein_iterator livein_begin() const { return LiveIns.begin(); }
779 livein_iterator livein_end() const { return LiveIns.end(); }
780 bool livein_empty() const { return LiveIns.empty(); }
782 bool isLiveIn(unsigned Reg) const;
784 /// getLiveInPhysReg - If VReg is a live-in virtual register, return the
785 /// corresponding live-in physical register.
786 unsigned getLiveInPhysReg(unsigned VReg) const;
788 /// getLiveInVirtReg - If PReg is a live-in physical register, return the
789 /// corresponding live-in physical register.
790 unsigned getLiveInVirtReg(unsigned PReg) const;
792 /// EmitLiveInCopies - Emit copies to initialize livein virtual registers
793 /// into the given entry block.
794 void EmitLiveInCopies(MachineBasicBlock *EntryMBB,
795 const TargetRegisterInfo &TRI,
796 const TargetInstrInfo &TII);
798 /// Returns a mask covering all bits that can appear in lane masks of
799 /// subregisters of the virtual register @p Reg.
800 unsigned getMaxLaneMaskForVReg(unsigned Reg) const;
802 /// defusechain_iterator - This class provides iterator support for machine
803 /// operands in the function that use or define a specific register. If
804 /// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
805 /// returns defs. If neither are true then you are silly and it always
806 /// returns end(). If SkipDebug is true it skips uses marked Debug
807 /// when incrementing.
808 template<bool ReturnUses, bool ReturnDefs, bool SkipDebug,
809 bool ByOperand, bool ByInstr, bool ByBundle>
810 class defusechain_iterator
811 : public std::iterator<std::forward_iterator_tag, MachineInstr, ptrdiff_t> {
813 explicit defusechain_iterator(MachineOperand *op) : Op(op) {
814 // If the first node isn't one we're interested in, advance to one that
815 // we are interested in.
817 if ((!ReturnUses && op->isUse()) ||
818 (!ReturnDefs && op->isDef()) ||
819 (SkipDebug && op->isDebug()))
823 friend class MachineRegisterInfo;
826 assert(Op && "Cannot increment end iterator!");
827 Op = getNextOperandForReg(Op);
829 // All defs come before the uses, so stop def_iterator early.
835 assert(!Op->isDebug() && "Can't have debug defs");
838 // If this is an operand we don't care about, skip it.
839 while (Op && ((!ReturnDefs && Op->isDef()) ||
840 (SkipDebug && Op->isDebug())))
841 Op = getNextOperandForReg(Op);
845 typedef std::iterator<std::forward_iterator_tag,
846 MachineInstr, ptrdiff_t>::reference reference;
847 typedef std::iterator<std::forward_iterator_tag,
848 MachineInstr, ptrdiff_t>::pointer pointer;
850 defusechain_iterator() : Op(nullptr) {}
852 bool operator==(const defusechain_iterator &x) const {
855 bool operator!=(const defusechain_iterator &x) const {
856 return !operator==(x);
859 /// atEnd - return true if this iterator is equal to reg_end() on the value.
860 bool atEnd() const { return Op == nullptr; }
862 // Iterator traversal: forward iteration only
863 defusechain_iterator &operator++() { // Preincrement
864 assert(Op && "Cannot increment end iterator!");
868 MachineInstr *P = Op->getParent();
871 } while (Op && Op->getParent() == P);
872 } else if (ByBundle) {
873 MachineInstr *P = getBundleStart(Op->getParent());
876 } while (Op && getBundleStart(Op->getParent()) == P);
881 defusechain_iterator operator++(int) { // Postincrement
882 defusechain_iterator tmp = *this; ++*this; return tmp;
885 /// getOperandNo - Return the operand # of this MachineOperand in its
887 unsigned getOperandNo() const {
888 assert(Op && "Cannot dereference end iterator!");
889 return Op - &Op->getParent()->getOperand(0);
892 // Retrieve a reference to the current operand.
893 MachineOperand &operator*() const {
894 assert(Op && "Cannot dereference end iterator!");
898 MachineOperand *operator->() const {
899 assert(Op && "Cannot dereference end iterator!");
904 /// defusechain_iterator - This class provides iterator support for machine
905 /// operands in the function that use or define a specific register. If
906 /// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
907 /// returns defs. If neither are true then you are silly and it always
908 /// returns end(). If SkipDebug is true it skips uses marked Debug
909 /// when incrementing.
910 template<bool ReturnUses, bool ReturnDefs, bool SkipDebug,
911 bool ByOperand, bool ByInstr, bool ByBundle>
912 class defusechain_instr_iterator
913 : public std::iterator<std::forward_iterator_tag, MachineInstr, ptrdiff_t> {
915 explicit defusechain_instr_iterator(MachineOperand *op) : Op(op) {
916 // If the first node isn't one we're interested in, advance to one that
917 // we are interested in.
919 if ((!ReturnUses && op->isUse()) ||
920 (!ReturnDefs && op->isDef()) ||
921 (SkipDebug && op->isDebug()))
925 friend class MachineRegisterInfo;
928 assert(Op && "Cannot increment end iterator!");
929 Op = getNextOperandForReg(Op);
931 // All defs come before the uses, so stop def_iterator early.
937 assert(!Op->isDebug() && "Can't have debug defs");
940 // If this is an operand we don't care about, skip it.
941 while (Op && ((!ReturnDefs && Op->isDef()) ||
942 (SkipDebug && Op->isDebug())))
943 Op = getNextOperandForReg(Op);
947 typedef std::iterator<std::forward_iterator_tag,
948 MachineInstr, ptrdiff_t>::reference reference;
949 typedef std::iterator<std::forward_iterator_tag,
950 MachineInstr, ptrdiff_t>::pointer pointer;
952 defusechain_instr_iterator() : Op(nullptr) {}
954 bool operator==(const defusechain_instr_iterator &x) const {
957 bool operator!=(const defusechain_instr_iterator &x) const {
958 return !operator==(x);
961 /// atEnd - return true if this iterator is equal to reg_end() on the value.
962 bool atEnd() const { return Op == nullptr; }
964 // Iterator traversal: forward iteration only
965 defusechain_instr_iterator &operator++() { // Preincrement
966 assert(Op && "Cannot increment end iterator!");
970 MachineInstr *P = Op->getParent();
973 } while (Op && Op->getParent() == P);
974 } else if (ByBundle) {
975 MachineInstr *P = getBundleStart(Op->getParent());
978 } while (Op && getBundleStart(Op->getParent()) == P);
983 defusechain_instr_iterator operator++(int) { // Postincrement
984 defusechain_instr_iterator tmp = *this; ++*this; return tmp;
987 // Retrieve a reference to the current operand.
988 MachineInstr &operator*() const {
989 assert(Op && "Cannot dereference end iterator!");
990 if (ByBundle) return *(getBundleStart(Op->getParent()));
991 return *Op->getParent();
994 MachineInstr *operator->() const {
995 assert(Op && "Cannot dereference end iterator!");
996 if (ByBundle) return getBundleStart(Op->getParent());
997 return Op->getParent();
1002 /// Iterate over the pressure sets affected by the given physical or virtual
1003 /// register. If Reg is physical, it must be a register unit (from
1004 /// MCRegUnitIterator).
1005 class PSetIterator {
1009 PSetIterator(): PSet(nullptr), Weight(0) {}
1010 PSetIterator(unsigned RegUnit, const MachineRegisterInfo *MRI) {
1011 const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
1012 if (TargetRegisterInfo::isVirtualRegister(RegUnit)) {
1013 const TargetRegisterClass *RC = MRI->getRegClass(RegUnit);
1014 PSet = TRI->getRegClassPressureSets(RC);
1015 Weight = TRI->getRegClassWeight(RC).RegWeight;
1018 PSet = TRI->getRegUnitPressureSets(RegUnit);
1019 Weight = TRI->getRegUnitWeight(RegUnit);
1024 bool isValid() const { return PSet; }
1026 unsigned getWeight() const { return Weight; }
1028 unsigned operator*() const { return *PSet; }
1031 assert(isValid() && "Invalid PSetIterator.");
1038 inline PSetIterator MachineRegisterInfo::
1039 getPressureSets(unsigned RegUnit) const {
1040 return PSetIterator(RegUnit, this);
1043 } // End llvm namespace