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 bool tracksSubRegLiveness() const { return TracksSubRegLiveness; }
187 void enableSubRegLiveness(bool Enable = true) {
188 TracksSubRegLiveness = Enable;
191 //===--------------------------------------------------------------------===//
193 //===--------------------------------------------------------------------===//
195 // Strictly for use by MachineInstr.cpp.
196 void addRegOperandToUseList(MachineOperand *MO);
198 // Strictly for use by MachineInstr.cpp.
199 void removeRegOperandFromUseList(MachineOperand *MO);
201 // Strictly for use by MachineInstr.cpp.
202 void moveOperands(MachineOperand *Dst, MachineOperand *Src, unsigned NumOps);
204 /// Verify the sanity of the use list for Reg.
205 void verifyUseList(unsigned Reg) const;
207 /// Verify the use list of all registers.
208 void verifyUseLists() const;
210 /// reg_begin/reg_end - Provide iteration support to walk over all definitions
211 /// and uses of a register within the MachineFunction that corresponds to this
212 /// MachineRegisterInfo object.
213 template<bool Uses, bool Defs, bool SkipDebug,
214 bool ByOperand, bool ByInstr, bool ByBundle>
215 class defusechain_iterator;
216 template<bool Uses, bool Defs, bool SkipDebug,
217 bool ByOperand, bool ByInstr, bool ByBundle>
218 class defusechain_instr_iterator;
220 // Make it a friend so it can access getNextOperandForReg().
221 template<bool, bool, bool, bool, bool, bool>
222 friend class defusechain_iterator;
223 template<bool, bool, bool, bool, bool, bool>
224 friend class defusechain_instr_iterator;
228 /// reg_iterator/reg_begin/reg_end - Walk all defs and uses of the specified
230 typedef defusechain_iterator<true,true,false,true,false,false>
232 reg_iterator reg_begin(unsigned RegNo) const {
233 return reg_iterator(getRegUseDefListHead(RegNo));
235 static reg_iterator reg_end() { return reg_iterator(nullptr); }
237 inline iterator_range<reg_iterator> reg_operands(unsigned Reg) const {
238 return iterator_range<reg_iterator>(reg_begin(Reg), reg_end());
241 /// reg_instr_iterator/reg_instr_begin/reg_instr_end - Walk all defs and uses
242 /// of the specified register, stepping by MachineInstr.
243 typedef defusechain_instr_iterator<true,true,false,false,true,false>
245 reg_instr_iterator reg_instr_begin(unsigned RegNo) const {
246 return reg_instr_iterator(getRegUseDefListHead(RegNo));
248 static reg_instr_iterator reg_instr_end() {
249 return reg_instr_iterator(nullptr);
252 inline iterator_range<reg_instr_iterator>
253 reg_instructions(unsigned Reg) const {
254 return iterator_range<reg_instr_iterator>(reg_instr_begin(Reg),
258 /// reg_bundle_iterator/reg_bundle_begin/reg_bundle_end - Walk all defs and uses
259 /// of the specified register, stepping by bundle.
260 typedef defusechain_instr_iterator<true,true,false,false,false,true>
262 reg_bundle_iterator reg_bundle_begin(unsigned RegNo) const {
263 return reg_bundle_iterator(getRegUseDefListHead(RegNo));
265 static reg_bundle_iterator reg_bundle_end() {
266 return reg_bundle_iterator(nullptr);
269 inline iterator_range<reg_bundle_iterator> reg_bundles(unsigned Reg) const {
270 return iterator_range<reg_bundle_iterator>(reg_bundle_begin(Reg),
274 /// reg_empty - Return true if there are no instructions using or defining the
275 /// specified register (it may be live-in).
276 bool reg_empty(unsigned RegNo) const { return reg_begin(RegNo) == reg_end(); }
278 /// reg_nodbg_iterator/reg_nodbg_begin/reg_nodbg_end - Walk all defs and uses
279 /// of the specified register, skipping those marked as Debug.
280 typedef defusechain_iterator<true,true,true,true,false,false>
282 reg_nodbg_iterator reg_nodbg_begin(unsigned RegNo) const {
283 return reg_nodbg_iterator(getRegUseDefListHead(RegNo));
285 static reg_nodbg_iterator reg_nodbg_end() {
286 return reg_nodbg_iterator(nullptr);
289 inline iterator_range<reg_nodbg_iterator>
290 reg_nodbg_operands(unsigned Reg) const {
291 return iterator_range<reg_nodbg_iterator>(reg_nodbg_begin(Reg),
295 /// reg_instr_nodbg_iterator/reg_instr_nodbg_begin/reg_instr_nodbg_end - Walk
296 /// all defs and uses of the specified register, stepping by MachineInstr,
297 /// skipping those marked as Debug.
298 typedef defusechain_instr_iterator<true,true,true,false,true,false>
299 reg_instr_nodbg_iterator;
300 reg_instr_nodbg_iterator reg_instr_nodbg_begin(unsigned RegNo) const {
301 return reg_instr_nodbg_iterator(getRegUseDefListHead(RegNo));
303 static reg_instr_nodbg_iterator reg_instr_nodbg_end() {
304 return reg_instr_nodbg_iterator(nullptr);
307 inline iterator_range<reg_instr_nodbg_iterator>
308 reg_nodbg_instructions(unsigned Reg) const {
309 return iterator_range<reg_instr_nodbg_iterator>(reg_instr_nodbg_begin(Reg),
310 reg_instr_nodbg_end());
313 /// reg_bundle_nodbg_iterator/reg_bundle_nodbg_begin/reg_bundle_nodbg_end - Walk
314 /// all defs and uses of the specified register, stepping by bundle,
315 /// skipping those marked as Debug.
316 typedef defusechain_instr_iterator<true,true,true,false,false,true>
317 reg_bundle_nodbg_iterator;
318 reg_bundle_nodbg_iterator reg_bundle_nodbg_begin(unsigned RegNo) const {
319 return reg_bundle_nodbg_iterator(getRegUseDefListHead(RegNo));
321 static reg_bundle_nodbg_iterator reg_bundle_nodbg_end() {
322 return reg_bundle_nodbg_iterator(nullptr);
325 inline iterator_range<reg_bundle_nodbg_iterator>
326 reg_nodbg_bundles(unsigned Reg) const {
327 return iterator_range<reg_bundle_nodbg_iterator>(reg_bundle_nodbg_begin(Reg),
328 reg_bundle_nodbg_end());
331 /// reg_nodbg_empty - Return true if the only instructions using or defining
332 /// Reg are Debug instructions.
333 bool reg_nodbg_empty(unsigned RegNo) const {
334 return reg_nodbg_begin(RegNo) == reg_nodbg_end();
337 /// def_iterator/def_begin/def_end - Walk all defs of the specified register.
338 typedef defusechain_iterator<false,true,false,true,false,false>
340 def_iterator def_begin(unsigned RegNo) const {
341 return def_iterator(getRegUseDefListHead(RegNo));
343 static def_iterator def_end() { return def_iterator(nullptr); }
345 inline iterator_range<def_iterator> def_operands(unsigned Reg) const {
346 return iterator_range<def_iterator>(def_begin(Reg), def_end());
349 /// def_instr_iterator/def_instr_begin/def_instr_end - Walk all defs of the
350 /// specified register, stepping by MachineInst.
351 typedef defusechain_instr_iterator<false,true,false,false,true,false>
353 def_instr_iterator def_instr_begin(unsigned RegNo) const {
354 return def_instr_iterator(getRegUseDefListHead(RegNo));
356 static def_instr_iterator def_instr_end() {
357 return def_instr_iterator(nullptr);
360 inline iterator_range<def_instr_iterator>
361 def_instructions(unsigned Reg) const {
362 return iterator_range<def_instr_iterator>(def_instr_begin(Reg),
366 /// def_bundle_iterator/def_bundle_begin/def_bundle_end - Walk all defs of the
367 /// specified register, stepping by bundle.
368 typedef defusechain_instr_iterator<false,true,false,false,false,true>
370 def_bundle_iterator def_bundle_begin(unsigned RegNo) const {
371 return def_bundle_iterator(getRegUseDefListHead(RegNo));
373 static def_bundle_iterator def_bundle_end() {
374 return def_bundle_iterator(nullptr);
377 inline iterator_range<def_bundle_iterator> def_bundles(unsigned Reg) const {
378 return iterator_range<def_bundle_iterator>(def_bundle_begin(Reg),
382 /// def_empty - Return true if there are no instructions defining the
383 /// specified register (it may be live-in).
384 bool def_empty(unsigned RegNo) const { return def_begin(RegNo) == def_end(); }
386 /// hasOneDef - Return true if there is exactly one instruction defining the
387 /// specified register.
388 bool hasOneDef(unsigned RegNo) const {
389 def_iterator DI = def_begin(RegNo);
392 return ++DI == def_end();
395 /// use_iterator/use_begin/use_end - Walk all uses of the specified register.
396 typedef defusechain_iterator<true,false,false,true,false,false>
398 use_iterator use_begin(unsigned RegNo) const {
399 return use_iterator(getRegUseDefListHead(RegNo));
401 static use_iterator use_end() { return use_iterator(nullptr); }
403 inline iterator_range<use_iterator> use_operands(unsigned Reg) const {
404 return iterator_range<use_iterator>(use_begin(Reg), use_end());
407 /// use_instr_iterator/use_instr_begin/use_instr_end - Walk all uses of the
408 /// specified register, stepping by MachineInstr.
409 typedef defusechain_instr_iterator<true,false,false,false,true,false>
411 use_instr_iterator use_instr_begin(unsigned RegNo) const {
412 return use_instr_iterator(getRegUseDefListHead(RegNo));
414 static use_instr_iterator use_instr_end() {
415 return use_instr_iterator(nullptr);
418 inline iterator_range<use_instr_iterator>
419 use_instructions(unsigned Reg) const {
420 return iterator_range<use_instr_iterator>(use_instr_begin(Reg),
424 /// use_bundle_iterator/use_bundle_begin/use_bundle_end - Walk all uses of the
425 /// specified register, stepping by bundle.
426 typedef defusechain_instr_iterator<true,false,false,false,false,true>
428 use_bundle_iterator use_bundle_begin(unsigned RegNo) const {
429 return use_bundle_iterator(getRegUseDefListHead(RegNo));
431 static use_bundle_iterator use_bundle_end() {
432 return use_bundle_iterator(nullptr);
435 inline iterator_range<use_bundle_iterator> use_bundles(unsigned Reg) const {
436 return iterator_range<use_bundle_iterator>(use_bundle_begin(Reg),
440 /// use_empty - Return true if there are no instructions using the specified
442 bool use_empty(unsigned RegNo) const { return use_begin(RegNo) == use_end(); }
444 /// hasOneUse - Return true if there is exactly one instruction using the
445 /// specified register.
446 bool hasOneUse(unsigned RegNo) const {
447 use_iterator UI = use_begin(RegNo);
450 return ++UI == use_end();
453 /// use_nodbg_iterator/use_nodbg_begin/use_nodbg_end - Walk all uses of the
454 /// specified register, skipping those marked as Debug.
455 typedef defusechain_iterator<true,false,true,true,false,false>
457 use_nodbg_iterator use_nodbg_begin(unsigned RegNo) const {
458 return use_nodbg_iterator(getRegUseDefListHead(RegNo));
460 static use_nodbg_iterator use_nodbg_end() {
461 return use_nodbg_iterator(nullptr);
464 inline iterator_range<use_nodbg_iterator>
465 use_nodbg_operands(unsigned Reg) const {
466 return iterator_range<use_nodbg_iterator>(use_nodbg_begin(Reg),
470 /// use_instr_nodbg_iterator/use_instr_nodbg_begin/use_instr_nodbg_end - Walk
471 /// all uses of the specified register, stepping by MachineInstr, skipping
472 /// those marked as Debug.
473 typedef defusechain_instr_iterator<true,false,true,false,true,false>
474 use_instr_nodbg_iterator;
475 use_instr_nodbg_iterator use_instr_nodbg_begin(unsigned RegNo) const {
476 return use_instr_nodbg_iterator(getRegUseDefListHead(RegNo));
478 static use_instr_nodbg_iterator use_instr_nodbg_end() {
479 return use_instr_nodbg_iterator(nullptr);
482 inline iterator_range<use_instr_nodbg_iterator>
483 use_nodbg_instructions(unsigned Reg) const {
484 return iterator_range<use_instr_nodbg_iterator>(use_instr_nodbg_begin(Reg),
485 use_instr_nodbg_end());
488 /// use_bundle_nodbg_iterator/use_bundle_nodbg_begin/use_bundle_nodbg_end - Walk
489 /// all uses of the specified register, stepping by bundle, skipping
490 /// those marked as Debug.
491 typedef defusechain_instr_iterator<true,false,true,false,false,true>
492 use_bundle_nodbg_iterator;
493 use_bundle_nodbg_iterator use_bundle_nodbg_begin(unsigned RegNo) const {
494 return use_bundle_nodbg_iterator(getRegUseDefListHead(RegNo));
496 static use_bundle_nodbg_iterator use_bundle_nodbg_end() {
497 return use_bundle_nodbg_iterator(nullptr);
500 inline iterator_range<use_bundle_nodbg_iterator>
501 use_nodbg_bundles(unsigned Reg) const {
502 return iterator_range<use_bundle_nodbg_iterator>(use_bundle_nodbg_begin(Reg),
503 use_bundle_nodbg_end());
506 /// use_nodbg_empty - Return true if there are no non-Debug instructions
507 /// using the specified register.
508 bool use_nodbg_empty(unsigned RegNo) const {
509 return use_nodbg_begin(RegNo) == use_nodbg_end();
512 /// hasOneNonDBGUse - Return true if there is exactly one non-Debug
513 /// instruction using the specified register.
514 bool hasOneNonDBGUse(unsigned RegNo) const;
516 /// replaceRegWith - Replace all instances of FromReg with ToReg in the
517 /// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
518 /// except that it also changes any definitions of the register as well.
520 /// Note that it is usually necessary to first constrain ToReg's register
521 /// class to match the FromReg constraints using:
523 /// constrainRegClass(ToReg, getRegClass(FromReg))
525 /// That function will return NULL if the virtual registers have incompatible
528 /// Note that if ToReg is a physical register the function will replace and
529 /// apply sub registers to ToReg in order to obtain a final/proper physical
531 void replaceRegWith(unsigned FromReg, unsigned ToReg);
533 /// getVRegDef - Return the machine instr that defines the specified virtual
534 /// register or null if none is found. This assumes that the code is in SSA
535 /// form, so there should only be one definition.
536 MachineInstr *getVRegDef(unsigned Reg) const;
538 /// getUniqueVRegDef - Return the unique machine instr that defines the
539 /// specified virtual register or null if none is found. If there are
540 /// multiple definitions or no definition, return null.
541 MachineInstr *getUniqueVRegDef(unsigned Reg) const;
543 /// clearKillFlags - Iterate over all the uses of the given register and
544 /// clear the kill flag from the MachineOperand. This function is used by
545 /// optimization passes which extend register lifetimes and need only
546 /// preserve conservative kill flag information.
547 void clearKillFlags(unsigned Reg) const;
550 void dumpUses(unsigned RegNo) const;
553 /// isConstantPhysReg - Returns true if PhysReg is unallocatable and constant
554 /// throughout the function. It is safe to move instructions that read such
556 bool isConstantPhysReg(unsigned PhysReg, const MachineFunction &MF) const;
558 /// Get an iterator over the pressure sets affected by the given physical or
559 /// virtual register. If RegUnit is physical, it must be a register unit (from
560 /// MCRegUnitIterator).
561 PSetIterator getPressureSets(unsigned RegUnit) const;
563 //===--------------------------------------------------------------------===//
564 // Virtual Register Info
565 //===--------------------------------------------------------------------===//
567 /// getRegClass - Return the register class of the specified virtual register.
569 const TargetRegisterClass *getRegClass(unsigned Reg) const {
570 return VRegInfo[Reg].first;
573 /// setRegClass - Set the register class of the specified virtual register.
575 void setRegClass(unsigned Reg, const TargetRegisterClass *RC);
577 /// constrainRegClass - Constrain the register class of the specified virtual
578 /// register to be a common subclass of RC and the current register class,
579 /// but only if the new class has at least MinNumRegs registers. Return the
580 /// new register class, or NULL if no such class exists.
581 /// This should only be used when the constraint is known to be trivial, like
582 /// GR32 -> GR32_NOSP. Beware of increasing register pressure.
584 const TargetRegisterClass *constrainRegClass(unsigned Reg,
585 const TargetRegisterClass *RC,
586 unsigned MinNumRegs = 0);
588 /// recomputeRegClass - Try to find a legal super-class of Reg's register
589 /// class that still satisfies the constraints from the instructions using
590 /// Reg. Returns true if Reg was upgraded.
592 /// This method can be used after constraints have been removed from a
593 /// virtual register, for example after removing instructions or splitting
596 bool recomputeRegClass(unsigned Reg);
598 /// createVirtualRegister - Create and return a new virtual register in the
599 /// function with the specified register class.
601 unsigned createVirtualRegister(const TargetRegisterClass *RegClass);
603 /// getNumVirtRegs - Return the number of virtual registers created.
605 unsigned getNumVirtRegs() const { return VRegInfo.size(); }
607 /// clearVirtRegs - Remove all virtual registers (after physreg assignment).
608 void clearVirtRegs();
610 /// setRegAllocationHint - Specify a register allocation hint for the
611 /// specified virtual register.
612 void setRegAllocationHint(unsigned Reg, unsigned Type, unsigned PrefReg) {
613 RegAllocHints[Reg].first = Type;
614 RegAllocHints[Reg].second = PrefReg;
617 /// getRegAllocationHint - Return the register allocation hint for the
618 /// specified virtual register.
619 std::pair<unsigned, unsigned>
620 getRegAllocationHint(unsigned Reg) const {
621 return RegAllocHints[Reg];
624 /// getSimpleHint - Return the preferred register allocation hint, or 0 if a
625 /// standard simple hint (Type == 0) is not set.
626 unsigned getSimpleHint(unsigned Reg) const {
627 std::pair<unsigned, unsigned> Hint = getRegAllocationHint(Reg);
628 return Hint.first ? 0 : Hint.second;
631 /// markUsesInDebugValueAsUndef - Mark every DBG_VALUE referencing the
632 /// specified register as undefined which causes the DBG_VALUE to be
633 /// deleted during LiveDebugVariables analysis.
634 void markUsesInDebugValueAsUndef(unsigned Reg) const;
636 //===--------------------------------------------------------------------===//
637 // Physical Register Use Info
638 //===--------------------------------------------------------------------===//
640 /// isPhysRegUsed - Return true if the specified register is used in this
641 /// function. Also check for clobbered aliases and registers clobbered by
642 /// function calls with register mask operands.
644 /// This only works after register allocation. It is primarily used by
645 /// PrologEpilogInserter to determine which callee-saved registers need
647 bool isPhysRegUsed(unsigned Reg) const {
648 if (UsedPhysRegMask.test(Reg))
650 for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
651 Units.isValid(); ++Units)
652 if (UsedRegUnits.test(*Units))
657 /// Mark the specified register unit as used in this function.
658 /// This should only be called during and after register allocation.
659 void setRegUnitUsed(unsigned RegUnit) {
660 UsedRegUnits.set(RegUnit);
663 /// setPhysRegUsed - Mark the specified register used in this function.
664 /// This should only be called during and after register allocation.
665 void setPhysRegUsed(unsigned Reg) {
666 for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
667 Units.isValid(); ++Units)
668 UsedRegUnits.set(*Units);
671 /// addPhysRegsUsedFromRegMask - Mark any registers not in RegMask as used.
672 /// This corresponds to the bit mask attached to register mask operands.
673 void addPhysRegsUsedFromRegMask(const uint32_t *RegMask) {
674 UsedPhysRegMask.setBitsNotInMask(RegMask);
677 /// setPhysRegUnused - Mark the specified register unused in this function.
678 /// This should only be called during and after register allocation.
679 void setPhysRegUnused(unsigned Reg) {
680 UsedPhysRegMask.reset(Reg);
681 for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
682 Units.isValid(); ++Units)
683 UsedRegUnits.reset(*Units);
687 //===--------------------------------------------------------------------===//
688 // Reserved Register Info
689 //===--------------------------------------------------------------------===//
691 // The set of reserved registers must be invariant during register
692 // allocation. For example, the target cannot suddenly decide it needs a
693 // frame pointer when the register allocator has already used the frame
694 // pointer register for something else.
696 // These methods can be used by target hooks like hasFP() to avoid changing
697 // the reserved register set during register allocation.
699 /// freezeReservedRegs - Called by the register allocator to freeze the set
700 /// of reserved registers before allocation begins.
701 void freezeReservedRegs(const MachineFunction&);
703 /// reservedRegsFrozen - Returns true after freezeReservedRegs() was called
704 /// to ensure the set of reserved registers stays constant.
705 bool reservedRegsFrozen() const {
706 return !ReservedRegs.empty();
709 /// canReserveReg - Returns true if PhysReg can be used as a reserved
710 /// register. Any register can be reserved before freezeReservedRegs() is
712 bool canReserveReg(unsigned PhysReg) const {
713 return !reservedRegsFrozen() || ReservedRegs.test(PhysReg);
716 /// getReservedRegs - Returns a reference to the frozen set of reserved
717 /// registers. This method should always be preferred to calling
718 /// TRI::getReservedRegs() when possible.
719 const BitVector &getReservedRegs() const {
720 assert(reservedRegsFrozen() &&
721 "Reserved registers haven't been frozen yet. "
722 "Use TRI::getReservedRegs().");
726 /// isReserved - Returns true when PhysReg is a reserved register.
728 /// Reserved registers may belong to an allocatable register class, but the
729 /// target has explicitly requested that they are not used.
731 bool isReserved(unsigned PhysReg) const {
732 return getReservedRegs().test(PhysReg);
735 /// isAllocatable - Returns true when PhysReg belongs to an allocatable
736 /// register class and it hasn't been reserved.
738 /// Allocatable registers may show up in the allocation order of some virtual
739 /// register, so a register allocator needs to track its liveness and
741 bool isAllocatable(unsigned PhysReg) const {
742 return getTargetRegisterInfo()->isInAllocatableClass(PhysReg) &&
743 !isReserved(PhysReg);
746 //===--------------------------------------------------------------------===//
748 //===--------------------------------------------------------------------===//
750 /// addLiveIn - Add the specified register as a live-in. Note that it
751 /// is an error to add the same register to the same set more than once.
752 void addLiveIn(unsigned Reg, unsigned vreg = 0) {
753 LiveIns.push_back(std::make_pair(Reg, vreg));
756 // Iteration support for the live-ins set. It's kept in sorted order
757 // by register number.
758 typedef std::vector<std::pair<unsigned,unsigned> >::const_iterator
760 livein_iterator livein_begin() const { return LiveIns.begin(); }
761 livein_iterator livein_end() const { return LiveIns.end(); }
762 bool livein_empty() const { return LiveIns.empty(); }
764 bool isLiveIn(unsigned Reg) const;
766 /// getLiveInPhysReg - If VReg is a live-in virtual register, return the
767 /// corresponding live-in physical register.
768 unsigned getLiveInPhysReg(unsigned VReg) const;
770 /// getLiveInVirtReg - If PReg is a live-in physical register, return the
771 /// corresponding live-in physical register.
772 unsigned getLiveInVirtReg(unsigned PReg) const;
774 /// EmitLiveInCopies - Emit copies to initialize livein virtual registers
775 /// into the given entry block.
776 void EmitLiveInCopies(MachineBasicBlock *EntryMBB,
777 const TargetRegisterInfo &TRI,
778 const TargetInstrInfo &TII);
780 /// Returns a mask covering all bits that can appear in lane masks of
781 /// subregisters of the virtual register @p Reg.
782 unsigned getMaxLaneMaskForVReg(unsigned Reg) const;
784 /// defusechain_iterator - This class provides iterator support for machine
785 /// operands in the function that use or define a specific register. If
786 /// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
787 /// returns defs. If neither are true then you are silly and it always
788 /// returns end(). If SkipDebug is true it skips uses marked Debug
789 /// when incrementing.
790 template<bool ReturnUses, bool ReturnDefs, bool SkipDebug,
791 bool ByOperand, bool ByInstr, bool ByBundle>
792 class defusechain_iterator
793 : public std::iterator<std::forward_iterator_tag, MachineInstr, ptrdiff_t> {
795 explicit defusechain_iterator(MachineOperand *op) : Op(op) {
796 // If the first node isn't one we're interested in, advance to one that
797 // we are interested in.
799 if ((!ReturnUses && op->isUse()) ||
800 (!ReturnDefs && op->isDef()) ||
801 (SkipDebug && op->isDebug()))
805 friend class MachineRegisterInfo;
808 assert(Op && "Cannot increment end iterator!");
809 Op = getNextOperandForReg(Op);
811 // All defs come before the uses, so stop def_iterator early.
817 assert(!Op->isDebug() && "Can't have debug defs");
820 // If this is an operand we don't care about, skip it.
821 while (Op && ((!ReturnDefs && Op->isDef()) ||
822 (SkipDebug && Op->isDebug())))
823 Op = getNextOperandForReg(Op);
827 typedef std::iterator<std::forward_iterator_tag,
828 MachineInstr, ptrdiff_t>::reference reference;
829 typedef std::iterator<std::forward_iterator_tag,
830 MachineInstr, ptrdiff_t>::pointer pointer;
832 defusechain_iterator() : Op(nullptr) {}
834 bool operator==(const defusechain_iterator &x) const {
837 bool operator!=(const defusechain_iterator &x) const {
838 return !operator==(x);
841 /// atEnd - return true if this iterator is equal to reg_end() on the value.
842 bool atEnd() const { return Op == nullptr; }
844 // Iterator traversal: forward iteration only
845 defusechain_iterator &operator++() { // Preincrement
846 assert(Op && "Cannot increment end iterator!");
850 MachineInstr *P = Op->getParent();
853 } while (Op && Op->getParent() == P);
854 } else if (ByBundle) {
855 MachineInstr *P = getBundleStart(Op->getParent());
858 } while (Op && getBundleStart(Op->getParent()) == P);
863 defusechain_iterator operator++(int) { // Postincrement
864 defusechain_iterator tmp = *this; ++*this; return tmp;
867 /// getOperandNo - Return the operand # of this MachineOperand in its
869 unsigned getOperandNo() const {
870 assert(Op && "Cannot dereference end iterator!");
871 return Op - &Op->getParent()->getOperand(0);
874 // Retrieve a reference to the current operand.
875 MachineOperand &operator*() const {
876 assert(Op && "Cannot dereference end iterator!");
880 MachineOperand *operator->() const {
881 assert(Op && "Cannot dereference end iterator!");
886 /// defusechain_iterator - This class provides iterator support for machine
887 /// operands in the function that use or define a specific register. If
888 /// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
889 /// returns defs. If neither are true then you are silly and it always
890 /// returns end(). If SkipDebug is true it skips uses marked Debug
891 /// when incrementing.
892 template<bool ReturnUses, bool ReturnDefs, bool SkipDebug,
893 bool ByOperand, bool ByInstr, bool ByBundle>
894 class defusechain_instr_iterator
895 : public std::iterator<std::forward_iterator_tag, MachineInstr, ptrdiff_t> {
897 explicit defusechain_instr_iterator(MachineOperand *op) : Op(op) {
898 // If the first node isn't one we're interested in, advance to one that
899 // we are interested in.
901 if ((!ReturnUses && op->isUse()) ||
902 (!ReturnDefs && op->isDef()) ||
903 (SkipDebug && op->isDebug()))
907 friend class MachineRegisterInfo;
910 assert(Op && "Cannot increment end iterator!");
911 Op = getNextOperandForReg(Op);
913 // All defs come before the uses, so stop def_iterator early.
919 assert(!Op->isDebug() && "Can't have debug defs");
922 // If this is an operand we don't care about, skip it.
923 while (Op && ((!ReturnDefs && Op->isDef()) ||
924 (SkipDebug && Op->isDebug())))
925 Op = getNextOperandForReg(Op);
929 typedef std::iterator<std::forward_iterator_tag,
930 MachineInstr, ptrdiff_t>::reference reference;
931 typedef std::iterator<std::forward_iterator_tag,
932 MachineInstr, ptrdiff_t>::pointer pointer;
934 defusechain_instr_iterator() : Op(nullptr) {}
936 bool operator==(const defusechain_instr_iterator &x) const {
939 bool operator!=(const defusechain_instr_iterator &x) const {
940 return !operator==(x);
943 /// atEnd - return true if this iterator is equal to reg_end() on the value.
944 bool atEnd() const { return Op == nullptr; }
946 // Iterator traversal: forward iteration only
947 defusechain_instr_iterator &operator++() { // Preincrement
948 assert(Op && "Cannot increment end iterator!");
952 MachineInstr *P = Op->getParent();
955 } while (Op && Op->getParent() == P);
956 } else if (ByBundle) {
957 MachineInstr *P = getBundleStart(Op->getParent());
960 } while (Op && getBundleStart(Op->getParent()) == P);
965 defusechain_instr_iterator operator++(int) { // Postincrement
966 defusechain_instr_iterator tmp = *this; ++*this; return tmp;
969 // Retrieve a reference to the current operand.
970 MachineInstr &operator*() const {
971 assert(Op && "Cannot dereference end iterator!");
972 if (ByBundle) return *(getBundleStart(Op->getParent()));
973 return *Op->getParent();
976 MachineInstr *operator->() const {
977 assert(Op && "Cannot dereference end iterator!");
978 if (ByBundle) return getBundleStart(Op->getParent());
979 return Op->getParent();
984 /// Iterate over the pressure sets affected by the given physical or virtual
985 /// register. If Reg is physical, it must be a register unit (from
986 /// MCRegUnitIterator).
991 PSetIterator(): PSet(nullptr), Weight(0) {}
992 PSetIterator(unsigned RegUnit, const MachineRegisterInfo *MRI) {
993 const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
994 if (TargetRegisterInfo::isVirtualRegister(RegUnit)) {
995 const TargetRegisterClass *RC = MRI->getRegClass(RegUnit);
996 PSet = TRI->getRegClassPressureSets(RC);
997 Weight = TRI->getRegClassWeight(RC).RegWeight;
1000 PSet = TRI->getRegUnitPressureSets(RegUnit);
1001 Weight = TRI->getRegUnitWeight(RegUnit);
1006 bool isValid() const { return PSet; }
1008 unsigned getWeight() const { return Weight; }
1010 unsigned operator*() const { return *PSet; }
1013 assert(isValid() && "Invalid PSetIterator.");
1020 inline PSetIterator MachineRegisterInfo::
1021 getPressureSets(unsigned RegUnit) const {
1022 return PSetIterator(RegUnit, this);
1025 } // End llvm namespace