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"
42 #include "llvm/Target/TargetSubtargetInfo.h"
48 #define DEBUG_TYPE "livedebug"
51 EnableLDV("live-debug-variables", cl::init(true),
52 cl::desc("Enable the live debug variables pass"), cl::Hidden);
54 STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted");
55 char LiveDebugVariables::ID = 0;
57 INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars",
58 "Debug Variable Analysis", false, false)
59 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
60 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
61 INITIALIZE_PASS_END(LiveDebugVariables, "livedebugvars",
62 "Debug Variable Analysis", false, false)
64 void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
65 AU.addRequired<MachineDominatorTree>();
66 AU.addRequiredTransitive<LiveIntervals>();
68 MachineFunctionPass::getAnalysisUsage(AU);
71 LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID), pImpl(nullptr) {
72 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
75 /// LocMap - Map of where a user value is live, and its location.
76 typedef IntervalMap<SlotIndex, unsigned, 4> LocMap;
79 /// UserValueScopes - Keeps track of lexical scopes associated with a
80 /// user value's source location.
81 class UserValueScopes {
84 SmallPtrSet<const MachineBasicBlock *, 4> LBlocks;
87 UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(D), LS(L) {}
89 /// dominates - Return true if current scope dominates at least one machine
90 /// instruction in a given machine basic block.
91 bool dominates(MachineBasicBlock *MBB) {
93 LS.getMachineBasicBlocks(DL, LBlocks);
94 if (LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB))
99 } // end anonymous namespace
101 /// UserValue - A user value is a part of a debug info user variable.
103 /// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
104 /// holds part of a user variable. The part is identified by a byte offset.
106 /// UserValues are grouped into equivalence classes for easier searching. Two
107 /// user values are related if they refer to the same variable, or if they are
108 /// held by the same virtual register. The equivalence class is the transitive
109 /// closure of that relation.
113 const MDNode *Variable; ///< The debug info variable we are part of.
114 const MDNode *Expression; ///< Any complex address expression.
115 unsigned offset; ///< Byte offset into variable.
116 bool IsIndirect; ///< true if this is a register-indirect+offset value.
117 DebugLoc dl; ///< The debug location for the variable. This is
118 ///< used by dwarf writer to find lexical scope.
119 UserValue *leader; ///< Equivalence class leader.
120 UserValue *next; ///< Next value in equivalence class, or null.
122 /// Numbered locations referenced by locmap.
123 SmallVector<MachineOperand, 4> locations;
125 /// Map of slot indices where this value is live.
128 /// coalesceLocation - After LocNo was changed, check if it has become
129 /// identical to another location, and coalesce them. This may cause LocNo or
130 /// a later location to be erased, but no earlier location will be erased.
131 void coalesceLocation(unsigned LocNo);
133 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
134 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
135 LiveIntervals &LIS, const TargetInstrInfo &TII);
137 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
138 /// is live. Returns true if any changes were made.
139 bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
143 /// UserValue - Create a new UserValue.
144 UserValue(const MDNode *var, const MDNode *expr, unsigned o, bool i,
145 DebugLoc L, LocMap::Allocator &alloc)
146 : Variable(var), Expression(expr), offset(o), IsIndirect(i), dl(L),
147 leader(this), next(nullptr), locInts(alloc) {}
149 /// getLeader - Get the leader of this value's equivalence class.
150 UserValue *getLeader() {
151 UserValue *l = leader;
152 while (l != l->leader)
157 /// getNext - Return the next UserValue in the equivalence class.
158 UserValue *getNext() const { return next; }
160 /// match - Does this UserValue match the parameters?
161 bool match(const MDNode *Var, const MDNode *Expr, unsigned Offset,
162 bool indirect) const {
163 return Var == Variable && Expr == Expression && Offset == offset &&
164 indirect == IsIndirect;
167 /// merge - Merge equivalence classes.
168 static UserValue *merge(UserValue *L1, UserValue *L2) {
169 L2 = L2->getLeader();
172 L1 = L1->getLeader();
175 // Splice L2 before L1's members.
178 End->leader = L1, End = End->next;
180 End->next = L1->next;
185 /// getLocationNo - Return the location number that matches Loc.
186 unsigned getLocationNo(const MachineOperand &LocMO) {
188 if (LocMO.getReg() == 0)
190 // For register locations we dont care about use/def and other flags.
191 for (unsigned i = 0, e = locations.size(); i != e; ++i)
192 if (locations[i].isReg() &&
193 locations[i].getReg() == LocMO.getReg() &&
194 locations[i].getSubReg() == LocMO.getSubReg())
197 for (unsigned i = 0, e = locations.size(); i != e; ++i)
198 if (LocMO.isIdenticalTo(locations[i]))
200 locations.push_back(LocMO);
201 // We are storing a MachineOperand outside a MachineInstr.
202 locations.back().clearParent();
203 // Don't store def operands.
204 if (locations.back().isReg())
205 locations.back().setIsUse();
206 return locations.size() - 1;
209 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
210 void mapVirtRegs(LDVImpl *LDV);
212 /// addDef - Add a definition point to this value.
213 void addDef(SlotIndex Idx, const MachineOperand &LocMO) {
214 // Add a singular (Idx,Idx) -> Loc mapping.
215 LocMap::iterator I = locInts.find(Idx);
216 if (!I.valid() || I.start() != Idx)
217 I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO));
219 // A later DBG_VALUE at the same SlotIndex overrides the old location.
220 I.setValue(getLocationNo(LocMO));
223 /// extendDef - Extend the current definition as far as possible down the
224 /// dominator tree. Stop when meeting an existing def or when leaving the live
226 /// End points where VNI is no longer live are added to Kills.
227 /// @param Idx Starting point for the definition.
228 /// @param LocNo Location number to propagate.
229 /// @param LR Restrict liveness to where LR has the value VNI. May be null.
230 /// @param VNI When LR is not null, this is the value to restrict to.
231 /// @param Kills Append end points of VNI's live range to Kills.
232 /// @param LIS Live intervals analysis.
233 /// @param MDT Dominator tree.
234 void extendDef(SlotIndex Idx, unsigned LocNo,
235 LiveRange *LR, const VNInfo *VNI,
236 SmallVectorImpl<SlotIndex> *Kills,
237 LiveIntervals &LIS, MachineDominatorTree &MDT,
238 UserValueScopes &UVS);
240 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
241 /// registers. Determine if any of the copies are available at the kill
242 /// points, and add defs if possible.
243 /// @param LI Scan for copies of the value in LI->reg.
244 /// @param LocNo Location number of LI->reg.
245 /// @param Kills Points where the range of LocNo could be extended.
246 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
247 void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
248 const SmallVectorImpl<SlotIndex> &Kills,
249 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
250 MachineRegisterInfo &MRI,
253 /// computeIntervals - Compute the live intervals of all locations after
254 /// collecting all their def points.
255 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
256 LiveIntervals &LIS, MachineDominatorTree &MDT,
257 UserValueScopes &UVS);
259 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
260 /// live. Returns true if any changes were made.
261 bool splitRegister(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
264 /// rewriteLocations - Rewrite virtual register locations according to the
265 /// provided virtual register map.
266 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
268 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
269 void emitDebugValues(VirtRegMap *VRM,
270 LiveIntervals &LIS, const TargetInstrInfo &TRI);
272 /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
273 /// variable may have more than one corresponding DBG_VALUE instructions.
274 /// Only first one needs DebugLoc to identify variable's lexical scope
276 DebugLoc findDebugLoc();
278 /// getDebugLoc - Return DebugLoc of this UserValue.
279 DebugLoc getDebugLoc() { return dl;}
280 void print(raw_ostream&, const TargetMachine*);
284 /// LDVImpl - Implementation of the LiveDebugVariables pass.
287 LiveDebugVariables &pass;
288 LocMap::Allocator allocator;
292 MachineDominatorTree *MDT;
293 const TargetRegisterInfo *TRI;
295 /// Whether emitDebugValues is called.
297 /// Whether the machine function is modified during the pass.
300 /// userValues - All allocated UserValue instances.
301 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
303 /// Map virtual register to eq class leader.
304 typedef DenseMap<unsigned, UserValue*> VRMap;
305 VRMap virtRegToEqClass;
307 /// Map user variable to eq class leader.
308 typedef DenseMap<const MDNode *, UserValue*> UVMap;
311 /// getUserValue - Find or create a UserValue.
312 UserValue *getUserValue(const MDNode *Var, const MDNode *Expr,
313 unsigned Offset, bool IsIndirect, DebugLoc DL);
315 /// lookupVirtReg - Find the EC leader for VirtReg or null.
316 UserValue *lookupVirtReg(unsigned VirtReg);
318 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
319 /// @param MI DBG_VALUE instruction
320 /// @param Idx Last valid SLotIndex before instruction.
321 /// @return True if the DBG_VALUE instruction should be deleted.
322 bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
324 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
325 /// a UserValue def for each instruction.
326 /// @param mf MachineFunction to be scanned.
327 /// @return True if any debug values were found.
328 bool collectDebugValues(MachineFunction &mf);
330 /// computeIntervals - Compute the live intervals of all user values after
331 /// collecting all their def points.
332 void computeIntervals();
335 LDVImpl(LiveDebugVariables *ps)
336 : pass(*ps), MF(nullptr), EmitDone(false), ModifiedMF(false) {}
337 bool runOnMachineFunction(MachineFunction &mf);
339 /// clear - Release all memory.
343 virtRegToEqClass.clear();
345 // Make sure we call emitDebugValues if the machine function was modified.
346 assert((!ModifiedMF || EmitDone) &&
347 "Dbg values are not emitted in LDV");
353 /// mapVirtReg - Map virtual register to an equivalence class.
354 void mapVirtReg(unsigned VirtReg, UserValue *EC);
356 /// splitRegister - Replace all references to OldReg with NewRegs.
357 void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
359 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
360 void emitDebugValues(VirtRegMap *VRM);
362 void print(raw_ostream&);
366 void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
367 DIVariable DV(Variable);
369 DV.printExtendedName(OS);
373 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
374 OS << " [" << I.start() << ';' << I.stop() << "):";
375 if (I.value() == ~0u)
380 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
381 OS << " Loc" << i << '=';
382 locations[i].print(OS, TM);
387 void LDVImpl::print(raw_ostream &OS) {
388 OS << "********** DEBUG VARIABLES **********\n";
389 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
390 userValues[i]->print(OS, &MF->getTarget());
393 void UserValue::coalesceLocation(unsigned LocNo) {
394 unsigned KeepLoc = 0;
395 for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
396 if (KeepLoc == LocNo)
398 if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
402 if (KeepLoc == locations.size())
405 // Keep the smaller location, erase the larger one.
406 unsigned EraseLoc = LocNo;
407 if (KeepLoc > EraseLoc)
408 std::swap(KeepLoc, EraseLoc);
409 locations.erase(locations.begin() + EraseLoc);
412 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
413 unsigned v = I.value();
415 I.setValue(KeepLoc); // Coalesce when possible.
416 else if (v > EraseLoc)
417 I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
421 void UserValue::mapVirtRegs(LDVImpl *LDV) {
422 for (unsigned i = 0, e = locations.size(); i != e; ++i)
423 if (locations[i].isReg() &&
424 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
425 LDV->mapVirtReg(locations[i].getReg(), this);
428 UserValue *LDVImpl::getUserValue(const MDNode *Var, const MDNode *Expr,
429 unsigned Offset, bool IsIndirect,
431 UserValue *&Leader = userVarMap[Var];
433 UserValue *UV = Leader->getLeader();
435 for (; UV; UV = UV->getNext())
436 if (UV->match(Var, Expr, Offset, IsIndirect))
440 userValues.push_back(
441 make_unique<UserValue>(Var, Expr, Offset, IsIndirect, DL, allocator));
442 UserValue *UV = userValues.back().get();
443 Leader = UserValue::merge(Leader, UV);
447 void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
448 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
449 UserValue *&Leader = virtRegToEqClass[VirtReg];
450 Leader = UserValue::merge(Leader, EC);
453 UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
454 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
455 return UV->getLeader();
459 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
460 // DBG_VALUE loc, offset, variable
461 if (MI->getNumOperands() != 4 ||
462 !(MI->getOperand(1).isReg() || MI->getOperand(1).isImm()) ||
463 !MI->getOperand(2).isMetadata()) {
464 DEBUG(dbgs() << "Can't handle " << *MI);
468 // Get or create the UserValue for (variable,offset).
469 bool IsIndirect = MI->isIndirectDebugValue();
470 unsigned Offset = IsIndirect ? MI->getOperand(1).getImm() : 0;
471 const MDNode *Var = MI->getDebugVariable();
472 const MDNode *Expr = MI->getDebugExpression();
475 getUserValue(Var, Expr, Offset, IsIndirect, MI->getDebugLoc());
476 UV->addDef(Idx, MI->getOperand(0));
480 bool LDVImpl::collectDebugValues(MachineFunction &mf) {
481 bool Changed = false;
482 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
484 MachineBasicBlock *MBB = MFI;
485 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
487 if (!MBBI->isDebugValue()) {
491 // DBG_VALUE has no slot index, use the previous instruction instead.
492 SlotIndex Idx = MBBI == MBB->begin() ?
493 LIS->getMBBStartIdx(MBB) :
494 LIS->getInstructionIndex(std::prev(MBBI)).getRegSlot();
495 // Handle consecutive DBG_VALUE instructions with the same slot index.
497 if (handleDebugValue(MBBI, Idx)) {
498 MBBI = MBB->erase(MBBI);
502 } while (MBBI != MBBE && MBBI->isDebugValue());
508 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
509 LiveRange *LR, const VNInfo *VNI,
510 SmallVectorImpl<SlotIndex> *Kills,
511 LiveIntervals &LIS, MachineDominatorTree &MDT,
512 UserValueScopes &UVS) {
513 SmallVector<SlotIndex, 16> Todo;
516 SlotIndex Start = Todo.pop_back_val();
517 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
518 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
519 LocMap::iterator I = locInts.find(Start);
521 // Limit to VNI's live range.
524 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
525 if (!Segment || Segment->valno != VNI) {
527 Kills->push_back(Start);
530 if (Segment->end < Stop)
531 Stop = Segment->end, ToEnd = false;
534 // There could already be a short def at Start.
535 if (I.valid() && I.start() <= Start) {
536 // Stop when meeting a different location or an already extended interval.
537 Start = Start.getNextSlot();
538 if (I.value() != LocNo || I.stop() != Start)
540 // This is a one-slot placeholder. Just skip it.
544 // Limited by the next def.
545 if (I.valid() && I.start() < Stop)
546 Stop = I.start(), ToEnd = false;
547 // Limited by VNI's live range.
548 else if (!ToEnd && Kills)
549 Kills->push_back(Stop);
554 I.insert(Start, Stop, LocNo);
556 // If we extended to the MBB end, propagate down the dominator tree.
559 const std::vector<MachineDomTreeNode*> &Children =
560 MDT.getNode(MBB)->getChildren();
561 for (unsigned i = 0, e = Children.size(); i != e; ++i) {
562 MachineBasicBlock *MBB = Children[i]->getBlock();
563 if (UVS.dominates(MBB))
564 Todo.push_back(LIS.getMBBStartIdx(MBB));
566 } while (!Todo.empty());
570 UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
571 const SmallVectorImpl<SlotIndex> &Kills,
572 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
573 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
576 // Don't track copies from physregs, there are too many uses.
577 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
580 // Collect all the (vreg, valno) pairs that are copies of LI.
581 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
582 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
583 MachineInstr *MI = MO.getParent();
584 // Copies of the full value.
585 if (MO.getSubReg() || !MI->isCopy())
587 unsigned DstReg = MI->getOperand(0).getReg();
589 // Don't follow copies to physregs. These are usually setting up call
590 // arguments, and the argument registers are always call clobbered. We are
591 // better off in the source register which could be a callee-saved register,
592 // or it could be spilled.
593 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
596 // Is LocNo extended to reach this copy? If not, another def may be blocking
597 // it, or we are looking at a wrong value of LI.
598 SlotIndex Idx = LIS.getInstructionIndex(MI);
599 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
600 if (!I.valid() || I.value() != LocNo)
603 if (!LIS.hasInterval(DstReg))
605 LiveInterval *DstLI = &LIS.getInterval(DstReg);
606 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
607 assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value");
608 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
611 if (CopyValues.empty())
614 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
616 // Try to add defs of the copied values for each kill point.
617 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
618 SlotIndex Idx = Kills[i];
619 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
620 LiveInterval *DstLI = CopyValues[j].first;
621 const VNInfo *DstVNI = CopyValues[j].second;
622 if (DstLI->getVNInfoAt(Idx) != DstVNI)
624 // Check that there isn't already a def at Idx
625 LocMap::iterator I = locInts.find(Idx);
626 if (I.valid() && I.start() <= Idx)
628 DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
629 << DstVNI->id << " in " << *DstLI << '\n');
630 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
631 assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
632 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
633 I.insert(Idx, Idx.getNextSlot(), LocNo);
634 NewDefs.push_back(std::make_pair(Idx, LocNo));
641 UserValue::computeIntervals(MachineRegisterInfo &MRI,
642 const TargetRegisterInfo &TRI,
644 MachineDominatorTree &MDT,
645 UserValueScopes &UVS) {
646 SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
648 // Collect all defs to be extended (Skipping undefs).
649 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
650 if (I.value() != ~0u)
651 Defs.push_back(std::make_pair(I.start(), I.value()));
653 // Extend all defs, and possibly add new ones along the way.
654 for (unsigned i = 0; i != Defs.size(); ++i) {
655 SlotIndex Idx = Defs[i].first;
656 unsigned LocNo = Defs[i].second;
657 const MachineOperand &Loc = locations[LocNo];
660 extendDef(Idx, LocNo, nullptr, nullptr, nullptr, LIS, MDT, UVS);
664 // Register locations are constrained to where the register value is live.
665 if (TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
666 LiveInterval *LI = nullptr;
667 const VNInfo *VNI = nullptr;
668 if (LIS.hasInterval(Loc.getReg())) {
669 LI = &LIS.getInterval(Loc.getReg());
670 VNI = LI->getVNInfoAt(Idx);
672 SmallVector<SlotIndex, 16> Kills;
673 extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS);
675 addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
679 // For physregs, use the live range of the first regunit as a guide.
680 unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
681 LiveRange *LR = &LIS.getRegUnit(Unit);
682 const VNInfo *VNI = LR->getVNInfoAt(Idx);
683 // Don't track copies from physregs, it is too expensive.
684 extendDef(Idx, LocNo, LR, VNI, nullptr, LIS, MDT, UVS);
687 // Finally, erase all the undefs.
688 for (LocMap::iterator I = locInts.begin(); I.valid();)
689 if (I.value() == ~0u)
695 void LDVImpl::computeIntervals() {
696 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
697 UserValueScopes UVS(userValues[i]->getDebugLoc(), LS);
698 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, *MDT, UVS);
699 userValues[i]->mapVirtRegs(this);
703 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
706 LIS = &pass.getAnalysis<LiveIntervals>();
707 MDT = &pass.getAnalysis<MachineDominatorTree>();
708 TRI = mf.getSubtarget().getRegisterInfo();
710 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
711 << mf.getName() << " **********\n");
713 bool Changed = collectDebugValues(mf);
715 DEBUG(print(dbgs()));
716 ModifiedMF = Changed;
720 static void removeDebugValues(MachineFunction &mf) {
721 for (MachineBasicBlock &MBB : mf) {
722 for (auto MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ) {
723 if (!MBBI->isDebugValue()) {
727 MBBI = MBB.erase(MBBI);
732 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
735 if (!FunctionDIs.count(mf.getFunction())) {
736 removeDebugValues(mf);
740 pImpl = new LDVImpl(this);
741 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
744 void LiveDebugVariables::releaseMemory() {
746 static_cast<LDVImpl*>(pImpl)->clear();
749 LiveDebugVariables::~LiveDebugVariables() {
751 delete static_cast<LDVImpl*>(pImpl);
754 //===----------------------------------------------------------------------===//
755 // Live Range Splitting
756 //===----------------------------------------------------------------------===//
759 UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
760 LiveIntervals& LIS) {
762 dbgs() << "Splitting Loc" << OldLocNo << '\t';
763 print(dbgs(), nullptr);
765 bool DidChange = false;
766 LocMap::iterator LocMapI;
767 LocMapI.setMap(locInts);
768 for (unsigned i = 0; i != NewRegs.size(); ++i) {
769 LiveInterval *LI = &LIS.getInterval(NewRegs[i]);
773 // Don't allocate the new LocNo until it is needed.
774 unsigned NewLocNo = ~0u;
776 // Iterate over the overlaps between locInts and LI.
777 LocMapI.find(LI->beginIndex());
778 if (!LocMapI.valid())
780 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
781 LiveInterval::iterator LIE = LI->end();
782 while (LocMapI.valid() && LII != LIE) {
783 // At this point, we know that LocMapI.stop() > LII->start.
784 LII = LI->advanceTo(LII, LocMapI.start());
788 // Now LII->end > LocMapI.start(). Do we have an overlap?
789 if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
790 // Overlapping correct location. Allocate NewLocNo now.
791 if (NewLocNo == ~0u) {
792 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
793 MO.setSubReg(locations[OldLocNo].getSubReg());
794 NewLocNo = getLocationNo(MO);
798 SlotIndex LStart = LocMapI.start();
799 SlotIndex LStop = LocMapI.stop();
801 // Trim LocMapI down to the LII overlap.
802 if (LStart < LII->start)
803 LocMapI.setStartUnchecked(LII->start);
804 if (LStop > LII->end)
805 LocMapI.setStopUnchecked(LII->end);
807 // Change the value in the overlap. This may trigger coalescing.
808 LocMapI.setValue(NewLocNo);
810 // Re-insert any removed OldLocNo ranges.
811 if (LStart < LocMapI.start()) {
812 LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
814 assert(LocMapI.valid() && "Unexpected coalescing");
816 if (LStop > LocMapI.stop()) {
818 LocMapI.insert(LII->end, LStop, OldLocNo);
823 // Advance to the next overlap.
824 if (LII->end < LocMapI.stop()) {
827 LocMapI.advanceTo(LII->start);
830 if (!LocMapI.valid())
832 LII = LI->advanceTo(LII, LocMapI.start());
837 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
838 locations.erase(locations.begin() + OldLocNo);
840 while (LocMapI.valid()) {
841 unsigned v = LocMapI.value();
843 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
844 << LocMapI.stop() << ")\n");
848 LocMapI.setValueUnchecked(v-1);
853 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), nullptr);});
858 UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
859 LiveIntervals &LIS) {
860 bool DidChange = false;
861 // Split locations referring to OldReg. Iterate backwards so splitLocation can
862 // safely erase unused locations.
863 for (unsigned i = locations.size(); i ; --i) {
864 unsigned LocNo = i-1;
865 const MachineOperand *Loc = &locations[LocNo];
866 if (!Loc->isReg() || Loc->getReg() != OldReg)
868 DidChange |= splitLocation(LocNo, NewRegs, LIS);
873 void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
874 bool DidChange = false;
875 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
876 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
881 // Map all of the new virtual registers.
882 UserValue *UV = lookupVirtReg(OldReg);
883 for (unsigned i = 0; i != NewRegs.size(); ++i)
884 mapVirtReg(NewRegs[i], UV);
887 void LiveDebugVariables::
888 splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
890 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
894 UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
895 // Iterate over locations in reverse makes it easier to handle coalescing.
896 for (unsigned i = locations.size(); i ; --i) {
897 unsigned LocNo = i-1;
898 MachineOperand &Loc = locations[LocNo];
899 // Only virtual registers are rewritten.
900 if (!Loc.isReg() || !Loc.getReg() ||
901 !TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
903 unsigned VirtReg = Loc.getReg();
904 if (VRM.isAssignedReg(VirtReg) &&
905 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
906 // This can create a %noreg operand in rare cases when the sub-register
907 // index is no longer available. That means the user value is in a
908 // non-existent sub-register, and %noreg is exactly what we want.
909 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
910 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
911 // FIXME: Translate SubIdx to a stackslot offset.
912 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
917 coalesceLocation(LocNo);
921 /// findInsertLocation - Find an iterator for inserting a DBG_VALUE
923 static MachineBasicBlock::iterator
924 findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
925 LiveIntervals &LIS) {
926 SlotIndex Start = LIS.getMBBStartIdx(MBB);
927 Idx = Idx.getBaseIndex();
929 // Try to find an insert location by going backwards from Idx.
931 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
932 // We've reached the beginning of MBB.
934 MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
937 Idx = Idx.getPrevIndex();
940 // Don't insert anything after the first terminator, though.
941 return MI->isTerminator() ? MBB->getFirstTerminator() :
942 std::next(MachineBasicBlock::iterator(MI));
945 DebugLoc UserValue::findDebugLoc() {
950 void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
953 const TargetInstrInfo &TII) {
954 MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
955 MachineOperand &Loc = locations[LocNo];
956 ++NumInsertedDebugValues;
959 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
960 IsIndirect, Loc.getReg(), offset, Variable, Expression);
962 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
965 .addMetadata(Variable)
966 .addMetadata(Expression);
969 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
970 const TargetInstrInfo &TII) {
971 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
973 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
974 SlotIndex Start = I.start();
975 SlotIndex Stop = I.stop();
976 unsigned LocNo = I.value();
977 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
978 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
979 SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
981 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
982 insertDebugValue(MBB, Start, LocNo, LIS, TII);
983 // This interval may span multiple basic blocks.
984 // Insert a DBG_VALUE into each one.
985 while(Stop > MBBEnd) {
986 // Move to the next block.
990 MBBEnd = LIS.getMBBEndIdx(MBB);
991 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
992 insertDebugValue(MBB, Start, LocNo, LIS, TII);
994 DEBUG(dbgs() << '\n');
1002 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
1003 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
1006 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1007 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
1008 DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
1009 userValues[i]->rewriteLocations(*VRM, *TRI);
1010 userValues[i]->emitDebugValues(VRM, *LIS, *TII);
1015 void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
1017 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
1020 bool LiveDebugVariables::doInitialization(Module &M) {
1021 FunctionDIs = makeSubprogramMap(M);
1022 return Pass::doInitialization(M);
1026 void LiveDebugVariables::dump() {
1028 static_cast<LDVImpl*>(pImpl)->print(dbgs());