1 //===- LiveDebugVariables.cpp - Tracking debug info variables -------------===//
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 implements the LiveDebugVariables analysis.
12 // Remove all DBG_VALUE instructions referencing virtual registers and replace
13 // them with a data structure tracking where live user variables are kept - in a
14 // virtual register or in a stack slot.
16 // Allow the data structure to be updated during register allocation when values
17 // are moved between registers and stack slots. Finally emit new DBG_VALUE
18 // instructions after register allocation is complete.
20 //===----------------------------------------------------------------------===//
22 #include "LiveDebugVariables.h"
23 #include "llvm/ADT/IntervalMap.h"
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/CodeGen/LexicalScopes.h"
26 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
27 #include "llvm/CodeGen/MachineDominators.h"
28 #include "llvm/CodeGen/MachineFunction.h"
29 #include "llvm/CodeGen/MachineInstrBuilder.h"
30 #include "llvm/CodeGen/MachineRegisterInfo.h"
31 #include "llvm/CodeGen/Passes.h"
32 #include "llvm/CodeGen/VirtRegMap.h"
33 #include "llvm/IR/Constants.h"
34 #include "llvm/IR/DebugInfo.h"
35 #include "llvm/IR/Metadata.h"
36 #include "llvm/IR/Value.h"
37 #include "llvm/Support/CommandLine.h"
38 #include "llvm/Support/Debug.h"
39 #include "llvm/Target/TargetInstrInfo.h"
40 #include "llvm/Target/TargetMachine.h"
41 #include "llvm/Target/TargetRegisterInfo.h"
47 #define DEBUG_TYPE "livedebug"
50 EnableLDV("live-debug-variables", cl::init(true),
51 cl::desc("Enable the live debug variables pass"), cl::Hidden);
53 STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted");
54 char LiveDebugVariables::ID = 0;
56 INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars",
57 "Debug Variable Analysis", false, false)
58 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
59 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
60 INITIALIZE_PASS_END(LiveDebugVariables, "livedebugvars",
61 "Debug Variable Analysis", false, false)
63 void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
64 AU.addRequired<MachineDominatorTree>();
65 AU.addRequiredTransitive<LiveIntervals>();
67 MachineFunctionPass::getAnalysisUsage(AU);
70 LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID), pImpl(nullptr) {
71 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
74 /// LocMap - Map of where a user value is live, and its location.
75 typedef IntervalMap<SlotIndex, unsigned, 4> LocMap;
78 /// UserValueScopes - Keeps track of lexical scopes associated with a
79 /// user value's source location.
80 class UserValueScopes {
83 SmallPtrSet<const MachineBasicBlock *, 4> LBlocks;
86 UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(D), LS(L) {}
88 /// dominates - Return true if current scope dominates at least one machine
89 /// instruction in a given machine basic block.
90 bool dominates(MachineBasicBlock *MBB) {
92 LS.getMachineBasicBlocks(DL, LBlocks);
93 if (LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB))
98 } // end anonymous namespace
100 /// UserValue - A user value is a part of a debug info user variable.
102 /// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
103 /// holds part of a user variable. The part is identified by a byte offset.
105 /// UserValues are grouped into equivalence classes for easier searching. Two
106 /// user values are related if they refer to the same variable, or if they are
107 /// held by the same virtual register. The equivalence class is the transitive
108 /// closure of that relation.
112 const MDNode *variable; ///< The debug info variable we are part of.
113 unsigned offset; ///< Byte offset into variable.
114 bool IsIndirect; ///< true if this is a register-indirect+offset value.
115 DebugLoc dl; ///< The debug location for the variable. This is
116 ///< used by dwarf writer to find lexical scope.
117 UserValue *leader; ///< Equivalence class leader.
118 UserValue *next; ///< Next value in equivalence class, or null.
120 /// Numbered locations referenced by locmap.
121 SmallVector<MachineOperand, 4> locations;
123 /// Map of slot indices where this value is live.
126 /// coalesceLocation - After LocNo was changed, check if it has become
127 /// identical to another location, and coalesce them. This may cause LocNo or
128 /// a later location to be erased, but no earlier location will be erased.
129 void coalesceLocation(unsigned LocNo);
131 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
132 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
133 LiveIntervals &LIS, const TargetInstrInfo &TII);
135 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
136 /// is live. Returns true if any changes were made.
137 bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
141 /// UserValue - Create a new UserValue.
142 UserValue(const MDNode *var, unsigned o, bool i, DebugLoc L,
143 LocMap::Allocator &alloc)
144 : variable(var), offset(o), IsIndirect(i), dl(L), leader(this),
145 next(nullptr), locInts(alloc)
148 /// getLeader - Get the leader of this value's equivalence class.
149 UserValue *getLeader() {
150 UserValue *l = leader;
151 while (l != l->leader)
156 /// getNext - Return the next UserValue in the equivalence class.
157 UserValue *getNext() const { return next; }
159 /// match - Does this UserValue match the parameters?
160 bool match(const MDNode *Var, unsigned Offset, bool indirect) const {
161 return Var == variable && Offset == offset && indirect == IsIndirect;
164 /// merge - Merge equivalence classes.
165 static UserValue *merge(UserValue *L1, UserValue *L2) {
166 L2 = L2->getLeader();
169 L1 = L1->getLeader();
172 // Splice L2 before L1's members.
175 End->leader = L1, End = End->next;
177 End->next = L1->next;
182 /// getLocationNo - Return the location number that matches Loc.
183 unsigned getLocationNo(const MachineOperand &LocMO) {
185 if (LocMO.getReg() == 0)
187 // For register locations we dont care about use/def and other flags.
188 for (unsigned i = 0, e = locations.size(); i != e; ++i)
189 if (locations[i].isReg() &&
190 locations[i].getReg() == LocMO.getReg() &&
191 locations[i].getSubReg() == LocMO.getSubReg())
194 for (unsigned i = 0, e = locations.size(); i != e; ++i)
195 if (LocMO.isIdenticalTo(locations[i]))
197 locations.push_back(LocMO);
198 // We are storing a MachineOperand outside a MachineInstr.
199 locations.back().clearParent();
200 // Don't store def operands.
201 if (locations.back().isReg())
202 locations.back().setIsUse();
203 return locations.size() - 1;
206 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
207 void mapVirtRegs(LDVImpl *LDV);
209 /// addDef - Add a definition point to this value.
210 void addDef(SlotIndex Idx, const MachineOperand &LocMO) {
211 // Add a singular (Idx,Idx) -> Loc mapping.
212 LocMap::iterator I = locInts.find(Idx);
213 if (!I.valid() || I.start() != Idx)
214 I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO));
216 // A later DBG_VALUE at the same SlotIndex overrides the old location.
217 I.setValue(getLocationNo(LocMO));
220 /// extendDef - Extend the current definition as far as possible down the
221 /// dominator tree. Stop when meeting an existing def or when leaving the live
223 /// End points where VNI is no longer live are added to Kills.
224 /// @param Idx Starting point for the definition.
225 /// @param LocNo Location number to propagate.
226 /// @param LR Restrict liveness to where LR has the value VNI. May be null.
227 /// @param VNI When LR is not null, this is the value to restrict to.
228 /// @param Kills Append end points of VNI's live range to Kills.
229 /// @param LIS Live intervals analysis.
230 /// @param MDT Dominator tree.
231 void extendDef(SlotIndex Idx, unsigned LocNo,
232 LiveRange *LR, const VNInfo *VNI,
233 SmallVectorImpl<SlotIndex> *Kills,
234 LiveIntervals &LIS, MachineDominatorTree &MDT,
235 UserValueScopes &UVS);
237 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
238 /// registers. Determine if any of the copies are available at the kill
239 /// points, and add defs if possible.
240 /// @param LI Scan for copies of the value in LI->reg.
241 /// @param LocNo Location number of LI->reg.
242 /// @param Kills Points where the range of LocNo could be extended.
243 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
244 void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
245 const SmallVectorImpl<SlotIndex> &Kills,
246 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
247 MachineRegisterInfo &MRI,
250 /// computeIntervals - Compute the live intervals of all locations after
251 /// collecting all their def points.
252 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
253 LiveIntervals &LIS, MachineDominatorTree &MDT,
254 UserValueScopes &UVS);
256 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
257 /// live. Returns true if any changes were made.
258 bool splitRegister(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
261 /// rewriteLocations - Rewrite virtual register locations according to the
262 /// provided virtual register map.
263 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
265 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
266 void emitDebugValues(VirtRegMap *VRM,
267 LiveIntervals &LIS, const TargetInstrInfo &TRI);
269 /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
270 /// variable may have more than one corresponding DBG_VALUE instructions.
271 /// Only first one needs DebugLoc to identify variable's lexical scope
273 DebugLoc findDebugLoc();
275 /// getDebugLoc - Return DebugLoc of this UserValue.
276 DebugLoc getDebugLoc() { return dl;}
277 void print(raw_ostream&, const TargetMachine*);
281 /// LDVImpl - Implementation of the LiveDebugVariables pass.
284 LiveDebugVariables &pass;
285 LocMap::Allocator allocator;
289 MachineDominatorTree *MDT;
290 const TargetRegisterInfo *TRI;
292 /// Whether emitDebugValues is called.
294 /// Whether the machine function is modified during the pass.
297 /// userValues - All allocated UserValue instances.
298 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
300 /// Map virtual register to eq class leader.
301 typedef DenseMap<unsigned, UserValue*> VRMap;
302 VRMap virtRegToEqClass;
304 /// Map user variable to eq class leader.
305 typedef DenseMap<const MDNode *, UserValue*> UVMap;
308 /// getUserValue - Find or create a UserValue.
309 UserValue *getUserValue(const MDNode *Var, unsigned Offset,
310 bool IsIndirect, DebugLoc DL);
312 /// lookupVirtReg - Find the EC leader for VirtReg or null.
313 UserValue *lookupVirtReg(unsigned VirtReg);
315 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
316 /// @param MI DBG_VALUE instruction
317 /// @param Idx Last valid SLotIndex before instruction.
318 /// @return True if the DBG_VALUE instruction should be deleted.
319 bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
321 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
322 /// a UserValue def for each instruction.
323 /// @param mf MachineFunction to be scanned.
324 /// @return True if any debug values were found.
325 bool collectDebugValues(MachineFunction &mf);
327 /// computeIntervals - Compute the live intervals of all user values after
328 /// collecting all their def points.
329 void computeIntervals();
332 LDVImpl(LiveDebugVariables *ps) : pass(*ps), EmitDone(false),
334 bool runOnMachineFunction(MachineFunction &mf);
336 /// clear - Release all memory.
339 virtRegToEqClass.clear();
341 // Make sure we call emitDebugValues if the machine function was modified.
342 assert((!ModifiedMF || EmitDone) &&
343 "Dbg values are not emitted in LDV");
348 /// mapVirtReg - Map virtual register to an equivalence class.
349 void mapVirtReg(unsigned VirtReg, UserValue *EC);
351 /// splitRegister - Replace all references to OldReg with NewRegs.
352 void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
354 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
355 void emitDebugValues(VirtRegMap *VRM);
357 void print(raw_ostream&);
361 void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
362 DIVariable DV(variable);
364 DV.printExtendedName(OS);
368 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
369 OS << " [" << I.start() << ';' << I.stop() << "):";
370 if (I.value() == ~0u)
375 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
376 OS << " Loc" << i << '=';
377 locations[i].print(OS, TM);
382 void LDVImpl::print(raw_ostream &OS) {
383 OS << "********** DEBUG VARIABLES **********\n";
384 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
385 userValues[i]->print(OS, &MF->getTarget());
388 void UserValue::coalesceLocation(unsigned LocNo) {
389 unsigned KeepLoc = 0;
390 for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
391 if (KeepLoc == LocNo)
393 if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
397 if (KeepLoc == locations.size())
400 // Keep the smaller location, erase the larger one.
401 unsigned EraseLoc = LocNo;
402 if (KeepLoc > EraseLoc)
403 std::swap(KeepLoc, EraseLoc);
404 locations.erase(locations.begin() + EraseLoc);
407 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
408 unsigned v = I.value();
410 I.setValue(KeepLoc); // Coalesce when possible.
411 else if (v > EraseLoc)
412 I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
416 void UserValue::mapVirtRegs(LDVImpl *LDV) {
417 for (unsigned i = 0, e = locations.size(); i != e; ++i)
418 if (locations[i].isReg() &&
419 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
420 LDV->mapVirtReg(locations[i].getReg(), this);
423 UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
424 bool IsIndirect, DebugLoc DL) {
425 UserValue *&Leader = userVarMap[Var];
427 UserValue *UV = Leader->getLeader();
429 for (; UV; UV = UV->getNext())
430 if (UV->match(Var, Offset, IsIndirect))
434 userValues.push_back(
435 make_unique<UserValue>(Var, Offset, IsIndirect, DL, allocator));
436 UserValue *UV = userValues.back().get();
437 Leader = UserValue::merge(Leader, UV);
441 void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
442 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
443 UserValue *&Leader = virtRegToEqClass[VirtReg];
444 Leader = UserValue::merge(Leader, EC);
447 UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
448 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
449 return UV->getLeader();
453 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
454 // DBG_VALUE loc, offset, variable
455 if (MI->getNumOperands() != 3 ||
456 !(MI->getOperand(1).isReg() || MI->getOperand(1).isImm()) ||
457 !MI->getOperand(2).isMetadata()) {
458 DEBUG(dbgs() << "Can't handle " << *MI);
462 // Get or create the UserValue for (variable,offset).
463 bool IsIndirect = MI->isIndirectDebugValue();
464 unsigned Offset = IsIndirect ? MI->getOperand(1).getImm() : 0;
465 const MDNode *Var = MI->getOperand(2).getMetadata();
467 UserValue *UV = getUserValue(Var, Offset, IsIndirect, MI->getDebugLoc());
468 UV->addDef(Idx, MI->getOperand(0));
472 bool LDVImpl::collectDebugValues(MachineFunction &mf) {
473 bool Changed = false;
474 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
476 MachineBasicBlock *MBB = MFI;
477 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
479 if (!MBBI->isDebugValue()) {
483 // DBG_VALUE has no slot index, use the previous instruction instead.
484 SlotIndex Idx = MBBI == MBB->begin() ?
485 LIS->getMBBStartIdx(MBB) :
486 LIS->getInstructionIndex(std::prev(MBBI)).getRegSlot();
487 // Handle consecutive DBG_VALUE instructions with the same slot index.
489 if (handleDebugValue(MBBI, Idx)) {
490 MBBI = MBB->erase(MBBI);
494 } while (MBBI != MBBE && MBBI->isDebugValue());
500 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
501 LiveRange *LR, const VNInfo *VNI,
502 SmallVectorImpl<SlotIndex> *Kills,
503 LiveIntervals &LIS, MachineDominatorTree &MDT,
504 UserValueScopes &UVS) {
505 SmallVector<SlotIndex, 16> Todo;
508 SlotIndex Start = Todo.pop_back_val();
509 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
510 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
511 LocMap::iterator I = locInts.find(Start);
513 // Limit to VNI's live range.
516 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
517 if (!Segment || Segment->valno != VNI) {
519 Kills->push_back(Start);
522 if (Segment->end < Stop)
523 Stop = Segment->end, ToEnd = false;
526 // There could already be a short def at Start.
527 if (I.valid() && I.start() <= Start) {
528 // Stop when meeting a different location or an already extended interval.
529 Start = Start.getNextSlot();
530 if (I.value() != LocNo || I.stop() != Start)
532 // This is a one-slot placeholder. Just skip it.
536 // Limited by the next def.
537 if (I.valid() && I.start() < Stop)
538 Stop = I.start(), ToEnd = false;
539 // Limited by VNI's live range.
540 else if (!ToEnd && Kills)
541 Kills->push_back(Stop);
546 I.insert(Start, Stop, LocNo);
548 // If we extended to the MBB end, propagate down the dominator tree.
551 const std::vector<MachineDomTreeNode*> &Children =
552 MDT.getNode(MBB)->getChildren();
553 for (unsigned i = 0, e = Children.size(); i != e; ++i) {
554 MachineBasicBlock *MBB = Children[i]->getBlock();
555 if (UVS.dominates(MBB))
556 Todo.push_back(LIS.getMBBStartIdx(MBB));
558 } while (!Todo.empty());
562 UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
563 const SmallVectorImpl<SlotIndex> &Kills,
564 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
565 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
568 // Don't track copies from physregs, there are too many uses.
569 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
572 // Collect all the (vreg, valno) pairs that are copies of LI.
573 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
574 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
575 MachineInstr *MI = MO.getParent();
576 // Copies of the full value.
577 if (MO.getSubReg() || !MI->isCopy())
579 unsigned DstReg = MI->getOperand(0).getReg();
581 // Don't follow copies to physregs. These are usually setting up call
582 // arguments, and the argument registers are always call clobbered. We are
583 // better off in the source register which could be a callee-saved register,
584 // or it could be spilled.
585 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
588 // Is LocNo extended to reach this copy? If not, another def may be blocking
589 // it, or we are looking at a wrong value of LI.
590 SlotIndex Idx = LIS.getInstructionIndex(MI);
591 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
592 if (!I.valid() || I.value() != LocNo)
595 if (!LIS.hasInterval(DstReg))
597 LiveInterval *DstLI = &LIS.getInterval(DstReg);
598 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
599 assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value");
600 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
603 if (CopyValues.empty())
606 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
608 // Try to add defs of the copied values for each kill point.
609 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
610 SlotIndex Idx = Kills[i];
611 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
612 LiveInterval *DstLI = CopyValues[j].first;
613 const VNInfo *DstVNI = CopyValues[j].second;
614 if (DstLI->getVNInfoAt(Idx) != DstVNI)
616 // Check that there isn't already a def at Idx
617 LocMap::iterator I = locInts.find(Idx);
618 if (I.valid() && I.start() <= Idx)
620 DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
621 << DstVNI->id << " in " << *DstLI << '\n');
622 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
623 assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
624 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
625 I.insert(Idx, Idx.getNextSlot(), LocNo);
626 NewDefs.push_back(std::make_pair(Idx, LocNo));
633 UserValue::computeIntervals(MachineRegisterInfo &MRI,
634 const TargetRegisterInfo &TRI,
636 MachineDominatorTree &MDT,
637 UserValueScopes &UVS) {
638 SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
640 // Collect all defs to be extended (Skipping undefs).
641 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
642 if (I.value() != ~0u)
643 Defs.push_back(std::make_pair(I.start(), I.value()));
645 // Extend all defs, and possibly add new ones along the way.
646 for (unsigned i = 0; i != Defs.size(); ++i) {
647 SlotIndex Idx = Defs[i].first;
648 unsigned LocNo = Defs[i].second;
649 const MachineOperand &Loc = locations[LocNo];
652 extendDef(Idx, LocNo, nullptr, nullptr, nullptr, LIS, MDT, UVS);
656 // Register locations are constrained to where the register value is live.
657 if (TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
658 LiveInterval *LI = nullptr;
659 const VNInfo *VNI = nullptr;
660 if (LIS.hasInterval(Loc.getReg())) {
661 LI = &LIS.getInterval(Loc.getReg());
662 VNI = LI->getVNInfoAt(Idx);
664 SmallVector<SlotIndex, 16> Kills;
665 extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS);
667 addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
671 // For physregs, use the live range of the first regunit as a guide.
672 unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
673 LiveRange *LR = &LIS.getRegUnit(Unit);
674 const VNInfo *VNI = LR->getVNInfoAt(Idx);
675 // Don't track copies from physregs, it is too expensive.
676 extendDef(Idx, LocNo, LR, VNI, nullptr, LIS, MDT, UVS);
679 // Finally, erase all the undefs.
680 for (LocMap::iterator I = locInts.begin(); I.valid();)
681 if (I.value() == ~0u)
687 void LDVImpl::computeIntervals() {
688 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
689 UserValueScopes UVS(userValues[i]->getDebugLoc(), LS);
690 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, *MDT, UVS);
691 userValues[i]->mapVirtRegs(this);
695 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
697 LIS = &pass.getAnalysis<LiveIntervals>();
698 MDT = &pass.getAnalysis<MachineDominatorTree>();
699 TRI = mf.getTarget().getRegisterInfo();
702 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
703 << mf.getName() << " **********\n");
705 bool Changed = collectDebugValues(mf);
707 DEBUG(print(dbgs()));
708 ModifiedMF = Changed;
712 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
716 pImpl = new LDVImpl(this);
717 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
720 void LiveDebugVariables::releaseMemory() {
722 static_cast<LDVImpl*>(pImpl)->clear();
725 LiveDebugVariables::~LiveDebugVariables() {
727 delete static_cast<LDVImpl*>(pImpl);
730 //===----------------------------------------------------------------------===//
731 // Live Range Splitting
732 //===----------------------------------------------------------------------===//
735 UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
736 LiveIntervals& LIS) {
738 dbgs() << "Splitting Loc" << OldLocNo << '\t';
739 print(dbgs(), nullptr);
741 bool DidChange = false;
742 LocMap::iterator LocMapI;
743 LocMapI.setMap(locInts);
744 for (unsigned i = 0; i != NewRegs.size(); ++i) {
745 LiveInterval *LI = &LIS.getInterval(NewRegs[i]);
749 // Don't allocate the new LocNo until it is needed.
750 unsigned NewLocNo = ~0u;
752 // Iterate over the overlaps between locInts and LI.
753 LocMapI.find(LI->beginIndex());
754 if (!LocMapI.valid())
756 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
757 LiveInterval::iterator LIE = LI->end();
758 while (LocMapI.valid() && LII != LIE) {
759 // At this point, we know that LocMapI.stop() > LII->start.
760 LII = LI->advanceTo(LII, LocMapI.start());
764 // Now LII->end > LocMapI.start(). Do we have an overlap?
765 if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
766 // Overlapping correct location. Allocate NewLocNo now.
767 if (NewLocNo == ~0u) {
768 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
769 MO.setSubReg(locations[OldLocNo].getSubReg());
770 NewLocNo = getLocationNo(MO);
774 SlotIndex LStart = LocMapI.start();
775 SlotIndex LStop = LocMapI.stop();
777 // Trim LocMapI down to the LII overlap.
778 if (LStart < LII->start)
779 LocMapI.setStartUnchecked(LII->start);
780 if (LStop > LII->end)
781 LocMapI.setStopUnchecked(LII->end);
783 // Change the value in the overlap. This may trigger coalescing.
784 LocMapI.setValue(NewLocNo);
786 // Re-insert any removed OldLocNo ranges.
787 if (LStart < LocMapI.start()) {
788 LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
790 assert(LocMapI.valid() && "Unexpected coalescing");
792 if (LStop > LocMapI.stop()) {
794 LocMapI.insert(LII->end, LStop, OldLocNo);
799 // Advance to the next overlap.
800 if (LII->end < LocMapI.stop()) {
803 LocMapI.advanceTo(LII->start);
806 if (!LocMapI.valid())
808 LII = LI->advanceTo(LII, LocMapI.start());
813 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
814 locations.erase(locations.begin() + OldLocNo);
816 while (LocMapI.valid()) {
817 unsigned v = LocMapI.value();
819 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
820 << LocMapI.stop() << ")\n");
824 LocMapI.setValueUnchecked(v-1);
829 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), nullptr);});
834 UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
835 LiveIntervals &LIS) {
836 bool DidChange = false;
837 // Split locations referring to OldReg. Iterate backwards so splitLocation can
838 // safely erase unused locations.
839 for (unsigned i = locations.size(); i ; --i) {
840 unsigned LocNo = i-1;
841 const MachineOperand *Loc = &locations[LocNo];
842 if (!Loc->isReg() || Loc->getReg() != OldReg)
844 DidChange |= splitLocation(LocNo, NewRegs, LIS);
849 void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
850 bool DidChange = false;
851 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
852 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
857 // Map all of the new virtual registers.
858 UserValue *UV = lookupVirtReg(OldReg);
859 for (unsigned i = 0; i != NewRegs.size(); ++i)
860 mapVirtReg(NewRegs[i], UV);
863 void LiveDebugVariables::
864 splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
866 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
870 UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
871 // Iterate over locations in reverse makes it easier to handle coalescing.
872 for (unsigned i = locations.size(); i ; --i) {
873 unsigned LocNo = i-1;
874 MachineOperand &Loc = locations[LocNo];
875 // Only virtual registers are rewritten.
876 if (!Loc.isReg() || !Loc.getReg() ||
877 !TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
879 unsigned VirtReg = Loc.getReg();
880 if (VRM.isAssignedReg(VirtReg) &&
881 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
882 // This can create a %noreg operand in rare cases when the sub-register
883 // index is no longer available. That means the user value is in a
884 // non-existent sub-register, and %noreg is exactly what we want.
885 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
886 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
887 // FIXME: Translate SubIdx to a stackslot offset.
888 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
893 coalesceLocation(LocNo);
897 /// findInsertLocation - Find an iterator for inserting a DBG_VALUE
899 static MachineBasicBlock::iterator
900 findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
901 LiveIntervals &LIS) {
902 SlotIndex Start = LIS.getMBBStartIdx(MBB);
903 Idx = Idx.getBaseIndex();
905 // Try to find an insert location by going backwards from Idx.
907 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
908 // We've reached the beginning of MBB.
910 MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
913 Idx = Idx.getPrevIndex();
916 // Don't insert anything after the first terminator, though.
917 return MI->isTerminator() ? MBB->getFirstTerminator() :
918 std::next(MachineBasicBlock::iterator(MI));
921 DebugLoc UserValue::findDebugLoc() {
926 void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
929 const TargetInstrInfo &TII) {
930 MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
931 MachineOperand &Loc = locations[LocNo];
932 ++NumInsertedDebugValues;
935 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
936 IsIndirect, Loc.getReg(), offset, variable);
938 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
939 .addOperand(Loc).addImm(offset).addMetadata(variable);
942 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
943 const TargetInstrInfo &TII) {
944 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
946 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
947 SlotIndex Start = I.start();
948 SlotIndex Stop = I.stop();
949 unsigned LocNo = I.value();
950 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
951 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
952 SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
954 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
955 insertDebugValue(MBB, Start, LocNo, LIS, TII);
956 // This interval may span multiple basic blocks.
957 // Insert a DBG_VALUE into each one.
958 while(Stop > MBBEnd) {
959 // Move to the next block.
963 MBBEnd = LIS.getMBBEndIdx(MBB);
964 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
965 insertDebugValue(MBB, Start, LocNo, LIS, TII);
967 DEBUG(dbgs() << '\n');
975 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
976 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
977 const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
978 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
979 DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
980 userValues[i]->rewriteLocations(*VRM, *TRI);
981 userValues[i]->emitDebugValues(VRM, *LIS, *TII);
986 void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
988 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
993 void LiveDebugVariables::dump() {
995 static_cast<LDVImpl*>(pImpl)->print(dbgs());