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 #define DEBUG_TYPE "livedebug"
23 #include "LiveDebugVariables.h"
24 #include "VirtRegMap.h"
25 #include "llvm/Constants.h"
26 #include "llvm/Metadata.h"
27 #include "llvm/Value.h"
28 #include "llvm/ADT/IntervalMap.h"
29 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
30 #include "llvm/CodeGen/MachineDominators.h"
31 #include "llvm/CodeGen/MachineFunction.h"
32 #include "llvm/CodeGen/MachineInstrBuilder.h"
33 #include "llvm/CodeGen/MachineRegisterInfo.h"
34 #include "llvm/CodeGen/Passes.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/Debug.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/Target/TargetMachine.h"
39 #include "llvm/Target/TargetRegisterInfo.h"
44 EnableLDV("live-debug-variables", cl::init(true),
45 cl::desc("Enable the live debug variables pass"), cl::Hidden);
47 char LiveDebugVariables::ID = 0;
49 INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars",
50 "Debug Variable Analysis", false, false)
51 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
52 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
53 INITIALIZE_PASS_END(LiveDebugVariables, "livedebugvars",
54 "Debug Variable Analysis", false, false)
56 void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
57 AU.addRequired<MachineDominatorTree>();
58 AU.addRequiredTransitive<LiveIntervals>();
60 MachineFunctionPass::getAnalysisUsage(AU);
63 LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID), pImpl(0) {
64 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
67 /// LocMap - Map of where a user value is live, and its location.
68 typedef IntervalMap<SlotIndex, unsigned, 4> LocMap;
70 /// UserValue - A user value is a part of a debug info user variable.
72 /// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
73 /// holds part of a user variable. The part is identified by a byte offset.
75 /// UserValues are grouped into equivalence classes for easier searching. Two
76 /// user values are related if they refer to the same variable, or if they are
77 /// held by the same virtual register. The equivalence class is the transitive
78 /// closure of that relation.
82 const MDNode *variable; ///< The debug info variable we are part of.
83 unsigned offset; ///< Byte offset into variable.
84 DebugLoc dl; ///< The debug location for the variable. This is
85 ///< used by dwarf writer to find lexical scope.
86 UserValue *leader; ///< Equivalence class leader.
87 UserValue *next; ///< Next value in equivalence class, or null.
89 /// Numbered locations referenced by locmap.
90 SmallVector<MachineOperand, 4> locations;
92 /// Map of slot indices where this value is live.
95 /// coalesceLocation - After LocNo was changed, check if it has become
96 /// identical to another location, and coalesce them. This may cause LocNo or
97 /// a later location to be erased, but no earlier location will be erased.
98 void coalesceLocation(unsigned LocNo);
100 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
101 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
102 LiveIntervals &LIS, const TargetInstrInfo &TII);
104 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
105 /// is live. Returns true if any changes were made.
106 bool splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
109 /// UserValue - Create a new UserValue.
110 UserValue(const MDNode *var, unsigned o, DebugLoc L,
111 LocMap::Allocator &alloc)
112 : variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc)
115 /// getLeader - Get the leader of this value's equivalence class.
116 UserValue *getLeader() {
117 UserValue *l = leader;
118 while (l != l->leader)
123 /// getNext - Return the next UserValue in the equivalence class.
124 UserValue *getNext() const { return next; }
126 /// match - Does this UserValue match the parameters?
127 bool match(const MDNode *Var, unsigned Offset) const {
128 return Var == variable && Offset == offset;
131 /// merge - Merge equivalence classes.
132 static UserValue *merge(UserValue *L1, UserValue *L2) {
133 L2 = L2->getLeader();
136 L1 = L1->getLeader();
139 // Splice L2 before L1's members.
142 End->leader = L1, End = End->next;
144 End->next = L1->next;
149 /// getLocationNo - Return the location number that matches Loc.
150 unsigned getLocationNo(const MachineOperand &LocMO) {
152 if (LocMO.getReg() == 0)
154 // For register locations we dont care about use/def and other flags.
155 for (unsigned i = 0, e = locations.size(); i != e; ++i)
156 if (locations[i].isReg() &&
157 locations[i].getReg() == LocMO.getReg() &&
158 locations[i].getSubReg() == LocMO.getSubReg())
161 for (unsigned i = 0, e = locations.size(); i != e; ++i)
162 if (LocMO.isIdenticalTo(locations[i]))
164 locations.push_back(LocMO);
165 // We are storing a MachineOperand outside a MachineInstr.
166 locations.back().clearParent();
167 // Don't store def operands.
168 if (locations.back().isReg())
169 locations.back().setIsUse();
170 return locations.size() - 1;
173 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
174 void mapVirtRegs(LDVImpl *LDV);
176 /// addDef - Add a definition point to this value.
177 void addDef(SlotIndex Idx, const MachineOperand &LocMO) {
178 // Add a singular (Idx,Idx) -> Loc mapping.
179 LocMap::iterator I = locInts.find(Idx);
180 if (!I.valid() || I.start() != Idx)
181 I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO));
183 // A later DBG_VALUE at the same SlotIndex overrides the old location.
184 I.setValue(getLocationNo(LocMO));
187 /// extendDef - Extend the current definition as far as possible down the
188 /// dominator tree. Stop when meeting an existing def or when leaving the live
190 /// End points where VNI is no longer live are added to Kills.
191 /// @param Idx Starting point for the definition.
192 /// @param LocNo Location number to propagate.
193 /// @param LI Restrict liveness to where LI has the value VNI. May be null.
194 /// @param VNI When LI is not null, this is the value to restrict to.
195 /// @param Kills Append end points of VNI's live range to Kills.
196 /// @param LIS Live intervals analysis.
197 /// @param MDT Dominator tree.
198 void extendDef(SlotIndex Idx, unsigned LocNo,
199 LiveInterval *LI, const VNInfo *VNI,
200 SmallVectorImpl<SlotIndex> *Kills,
201 LiveIntervals &LIS, MachineDominatorTree &MDT);
203 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
204 /// registers. Determine if any of the copies are available at the kill
205 /// points, and add defs if possible.
206 /// @param LI Scan for copies of the value in LI->reg.
207 /// @param LocNo Location number of LI->reg.
208 /// @param Kills Points where the range of LocNo could be extended.
209 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
210 void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
211 const SmallVectorImpl<SlotIndex> &Kills,
212 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
213 MachineRegisterInfo &MRI,
216 /// computeIntervals - Compute the live intervals of all locations after
217 /// collecting all their def points.
218 void computeIntervals(MachineRegisterInfo &MRI,
219 LiveIntervals &LIS, MachineDominatorTree &MDT);
221 /// renameRegister - Update locations to rewrite OldReg as NewReg:SubIdx.
222 void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
223 const TargetRegisterInfo *TRI);
225 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
226 /// live. Returns true if any changes were made.
227 bool splitRegister(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
229 /// rewriteLocations - Rewrite virtual register locations according to the
230 /// provided virtual register map.
231 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
233 /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
234 void emitDebugValues(VirtRegMap *VRM,
235 LiveIntervals &LIS, const TargetInstrInfo &TRI);
237 /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
238 /// variable may have more than one corresponding DBG_VALUE instructions.
239 /// Only first one needs DebugLoc to identify variable's lexical scope
241 DebugLoc findDebugLoc();
242 void print(raw_ostream&, const TargetMachine*);
246 /// LDVImpl - Implementation of the LiveDebugVariables pass.
249 LiveDebugVariables &pass;
250 LocMap::Allocator allocator;
253 MachineDominatorTree *MDT;
254 const TargetRegisterInfo *TRI;
256 /// userValues - All allocated UserValue instances.
257 SmallVector<UserValue*, 8> userValues;
259 /// Map virtual register to eq class leader.
260 typedef DenseMap<unsigned, UserValue*> VRMap;
261 VRMap virtRegToEqClass;
263 /// Map user variable to eq class leader.
264 typedef DenseMap<const MDNode *, UserValue*> UVMap;
267 /// getUserValue - Find or create a UserValue.
268 UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL);
270 /// lookupVirtReg - Find the EC leader for VirtReg or null.
271 UserValue *lookupVirtReg(unsigned VirtReg);
273 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
274 /// @param MI DBG_VALUE instruction
275 /// @param Idx Last valid SLotIndex before instruction.
276 /// @return True if the DBG_VALUE instruction should be deleted.
277 bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
279 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
280 /// a UserValue def for each instruction.
281 /// @param mf MachineFunction to be scanned.
282 /// @return True if any debug values were found.
283 bool collectDebugValues(MachineFunction &mf);
285 /// computeIntervals - Compute the live intervals of all user values after
286 /// collecting all their def points.
287 void computeIntervals();
290 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
291 bool runOnMachineFunction(MachineFunction &mf);
293 /// clear - Relase all memory.
295 DeleteContainerPointers(userValues);
297 virtRegToEqClass.clear();
301 /// mapVirtReg - Map virtual register to an equivalence class.
302 void mapVirtReg(unsigned VirtReg, UserValue *EC);
304 /// renameRegister - Replace all references to OldReg with NewReg:SubIdx.
305 void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
307 /// splitRegister - Replace all references to OldReg with NewRegs.
308 void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs);
310 /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
311 void emitDebugValues(VirtRegMap *VRM);
313 void print(raw_ostream&);
317 void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
318 if (const MDString *MDS = dyn_cast<MDString>(variable->getOperand(2)))
319 OS << "!\"" << MDS->getString() << "\"\t";
322 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
323 OS << " [" << I.start() << ';' << I.stop() << "):";
324 if (I.value() == ~0u)
329 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
330 OS << " Loc" << i << '=';
331 locations[i].print(OS, TM);
336 void LDVImpl::print(raw_ostream &OS) {
337 OS << "********** DEBUG VARIABLES **********\n";
338 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
339 userValues[i]->print(OS, &MF->getTarget());
342 void UserValue::coalesceLocation(unsigned LocNo) {
343 unsigned KeepLoc = 0;
344 for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
345 if (KeepLoc == LocNo)
347 if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
351 if (KeepLoc == locations.size())
354 // Keep the smaller location, erase the larger one.
355 unsigned EraseLoc = LocNo;
356 if (KeepLoc > EraseLoc)
357 std::swap(KeepLoc, EraseLoc);
358 locations.erase(locations.begin() + EraseLoc);
361 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
362 unsigned v = I.value();
364 I.setValue(KeepLoc); // Coalesce when possible.
365 else if (v > EraseLoc)
366 I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
370 void UserValue::mapVirtRegs(LDVImpl *LDV) {
371 for (unsigned i = 0, e = locations.size(); i != e; ++i)
372 if (locations[i].isReg() &&
373 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
374 LDV->mapVirtReg(locations[i].getReg(), this);
377 UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
379 UserValue *&Leader = userVarMap[Var];
381 UserValue *UV = Leader->getLeader();
383 for (; UV; UV = UV->getNext())
384 if (UV->match(Var, Offset))
388 UserValue *UV = new UserValue(Var, Offset, DL, allocator);
389 userValues.push_back(UV);
390 Leader = UserValue::merge(Leader, UV);
394 void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
395 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
396 UserValue *&Leader = virtRegToEqClass[VirtReg];
397 Leader = UserValue::merge(Leader, EC);
400 UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
401 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
402 return UV->getLeader();
406 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
407 // DBG_VALUE loc, offset, variable
408 if (MI->getNumOperands() != 3 ||
409 !MI->getOperand(1).isImm() || !MI->getOperand(2).isMetadata()) {
410 DEBUG(dbgs() << "Can't handle " << *MI);
414 // Get or create the UserValue for (variable,offset).
415 unsigned Offset = MI->getOperand(1).getImm();
416 const MDNode *Var = MI->getOperand(2).getMetadata();
417 UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc());
418 UV->addDef(Idx, MI->getOperand(0));
422 bool LDVImpl::collectDebugValues(MachineFunction &mf) {
423 bool Changed = false;
424 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
426 MachineBasicBlock *MBB = MFI;
427 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
429 if (!MBBI->isDebugValue()) {
433 // DBG_VALUE has no slot index, use the previous instruction instead.
434 SlotIndex Idx = MBBI == MBB->begin() ?
435 LIS->getMBBStartIdx(MBB) :
436 LIS->getInstructionIndex(llvm::prior(MBBI)).getDefIndex();
437 // Handle consecutive DBG_VALUE instructions with the same slot index.
439 if (handleDebugValue(MBBI, Idx)) {
440 MBBI = MBB->erase(MBBI);
444 } while (MBBI != MBBE && MBBI->isDebugValue());
450 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
451 LiveInterval *LI, const VNInfo *VNI,
452 SmallVectorImpl<SlotIndex> *Kills,
453 LiveIntervals &LIS, MachineDominatorTree &MDT) {
454 SmallVector<SlotIndex, 16> Todo;
458 SlotIndex Start = Todo.pop_back_val();
459 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
460 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
461 LocMap::iterator I = locInts.find(Start);
463 // Limit to VNI's live range.
466 LiveRange *Range = LI->getLiveRangeContaining(Start);
467 if (!Range || Range->valno != VNI) {
469 Kills->push_back(Start);
472 if (Range->end < Stop)
473 Stop = Range->end, ToEnd = false;
476 // There could already be a short def at Start.
477 if (I.valid() && I.start() <= Start) {
478 // Stop when meeting a different location or an already extended interval.
479 Start = Start.getNextSlot();
480 if (I.value() != LocNo || I.stop() != Start)
482 // This is a one-slot placeholder. Just skip it.
486 // Limited by the next def.
487 if (I.valid() && I.start() < Stop)
488 Stop = I.start(), ToEnd = false;
489 // Limited by VNI's live range.
490 else if (!ToEnd && Kills)
491 Kills->push_back(Stop);
496 I.insert(Start, Stop, LocNo);
498 // If we extended to the MBB end, propagate down the dominator tree.
501 const std::vector<MachineDomTreeNode*> &Children =
502 MDT.getNode(MBB)->getChildren();
503 for (unsigned i = 0, e = Children.size(); i != e; ++i)
504 Todo.push_back(LIS.getMBBStartIdx(Children[i]->getBlock()));
505 } while (!Todo.empty());
509 UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
510 const SmallVectorImpl<SlotIndex> &Kills,
511 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
512 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
515 // Don't track copies from physregs, there are too many uses.
516 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
519 // Collect all the (vreg, valno) pairs that are copies of LI.
520 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
521 for (MachineRegisterInfo::use_nodbg_iterator
522 UI = MRI.use_nodbg_begin(LI->reg),
523 UE = MRI.use_nodbg_end(); UI != UE; ++UI) {
524 // Copies of the full value.
525 if (UI.getOperand().getSubReg() || !UI->isCopy())
527 MachineInstr *MI = &*UI;
528 unsigned DstReg = MI->getOperand(0).getReg();
530 // Don't follow copies to physregs. These are usually setting up call
531 // arguments, and the argument registers are always call clobbered. We are
532 // better off in the source register which could be a callee-saved register,
533 // or it could be spilled.
534 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
537 // Is LocNo extended to reach this copy? If not, another def may be blocking
538 // it, or we are looking at a wrong value of LI.
539 SlotIndex Idx = LIS.getInstructionIndex(MI);
540 LocMap::iterator I = locInts.find(Idx.getUseIndex());
541 if (!I.valid() || I.value() != LocNo)
544 if (!LIS.hasInterval(DstReg))
546 LiveInterval *DstLI = &LIS.getInterval(DstReg);
547 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getDefIndex());
548 assert(DstVNI && DstVNI->def == Idx.getDefIndex() && "Bad copy value");
549 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
552 if (CopyValues.empty())
555 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
557 // Try to add defs of the copied values for each kill point.
558 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
559 SlotIndex Idx = Kills[i];
560 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
561 LiveInterval *DstLI = CopyValues[j].first;
562 const VNInfo *DstVNI = CopyValues[j].second;
563 if (DstLI->getVNInfoAt(Idx) != DstVNI)
565 // Check that there isn't already a def at Idx
566 LocMap::iterator I = locInts.find(Idx);
567 if (I.valid() && I.start() <= Idx)
569 DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
570 << DstVNI->id << " in " << *DstLI << '\n');
571 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
572 assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
573 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
574 I.insert(Idx, Idx.getNextSlot(), LocNo);
575 NewDefs.push_back(std::make_pair(Idx, LocNo));
582 UserValue::computeIntervals(MachineRegisterInfo &MRI,
584 MachineDominatorTree &MDT) {
585 SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
587 // Collect all defs to be extended (Skipping undefs).
588 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
589 if (I.value() != ~0u)
590 Defs.push_back(std::make_pair(I.start(), I.value()));
592 // Extend all defs, and possibly add new ones along the way.
593 for (unsigned i = 0; i != Defs.size(); ++i) {
594 SlotIndex Idx = Defs[i].first;
595 unsigned LocNo = Defs[i].second;
596 const MachineOperand &Loc = locations[LocNo];
598 // Register locations are constrained to where the register value is live.
599 if (Loc.isReg() && LIS.hasInterval(Loc.getReg())) {
600 LiveInterval *LI = &LIS.getInterval(Loc.getReg());
601 const VNInfo *VNI = LI->getVNInfoAt(Idx);
602 SmallVector<SlotIndex, 16> Kills;
603 extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT);
604 addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
606 extendDef(Idx, LocNo, 0, 0, 0, LIS, MDT);
609 // Finally, erase all the undefs.
610 for (LocMap::iterator I = locInts.begin(); I.valid();)
611 if (I.value() == ~0u)
617 void LDVImpl::computeIntervals() {
618 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
619 userValues[i]->computeIntervals(MF->getRegInfo(), *LIS, *MDT);
620 userValues[i]->mapVirtRegs(this);
624 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
626 LIS = &pass.getAnalysis<LiveIntervals>();
627 MDT = &pass.getAnalysis<MachineDominatorTree>();
628 TRI = mf.getTarget().getRegisterInfo();
630 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
631 << ((Value*)mf.getFunction())->getName()
634 bool Changed = collectDebugValues(mf);
636 DEBUG(print(dbgs()));
640 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
644 pImpl = new LDVImpl(this);
645 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
648 void LiveDebugVariables::releaseMemory() {
650 static_cast<LDVImpl*>(pImpl)->clear();
653 LiveDebugVariables::~LiveDebugVariables() {
655 delete static_cast<LDVImpl*>(pImpl);
659 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
660 const TargetRegisterInfo *TRI) {
661 for (unsigned i = locations.size(); i; --i) {
662 unsigned LocNo = i - 1;
663 MachineOperand &Loc = locations[LocNo];
664 if (!Loc.isReg() || Loc.getReg() != OldReg)
666 if (TargetRegisterInfo::isPhysicalRegister(NewReg))
667 Loc.substPhysReg(NewReg, *TRI);
669 Loc.substVirtReg(NewReg, SubIdx, *TRI);
670 coalesceLocation(LocNo);
675 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) {
676 UserValue *UV = lookupVirtReg(OldReg);
680 if (TargetRegisterInfo::isVirtualRegister(NewReg))
681 mapVirtReg(NewReg, UV);
682 virtRegToEqClass.erase(OldReg);
685 UV->renameRegister(OldReg, NewReg, SubIdx, TRI);
690 void LiveDebugVariables::
691 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) {
693 static_cast<LDVImpl*>(pImpl)->renameRegister(OldReg, NewReg, SubIdx);
696 //===----------------------------------------------------------------------===//
697 // Live Range Splitting
698 //===----------------------------------------------------------------------===//
701 UserValue::splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs) {
703 dbgs() << "Splitting Loc" << OldLocNo << '\t';
706 bool DidChange = false;
707 LocMap::iterator LocMapI;
708 LocMapI.setMap(locInts);
709 for (unsigned i = 0; i != NewRegs.size(); ++i) {
710 LiveInterval *LI = NewRegs[i];
714 // Don't allocate the new LocNo until it is needed.
715 unsigned NewLocNo = ~0u;
717 // Iterate over the overlaps between locInts and LI.
718 LocMapI.find(LI->beginIndex());
719 if (!LocMapI.valid())
721 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
722 LiveInterval::iterator LIE = LI->end();
723 while (LocMapI.valid() && LII != LIE) {
724 // At this point, we know that LocMapI.stop() > LII->start.
725 LII = LI->advanceTo(LII, LocMapI.start());
729 // Now LII->end > LocMapI.start(). Do we have an overlap?
730 if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
731 // Overlapping correct location. Allocate NewLocNo now.
732 if (NewLocNo == ~0u) {
733 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
734 MO.setSubReg(locations[OldLocNo].getSubReg());
735 NewLocNo = getLocationNo(MO);
739 SlotIndex LStart = LocMapI.start();
740 SlotIndex LStop = LocMapI.stop();
742 // Trim LocMapI down to the LII overlap.
743 if (LStart < LII->start)
744 LocMapI.setStartUnchecked(LII->start);
745 if (LStop > LII->end)
746 LocMapI.setStopUnchecked(LII->end);
748 // Change the value in the overlap. This may trigger coalescing.
749 LocMapI.setValue(NewLocNo);
751 // Re-insert any removed OldLocNo ranges.
752 if (LStart < LocMapI.start()) {
753 LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
755 assert(LocMapI.valid() && "Unexpected coalescing");
757 if (LStop > LocMapI.stop()) {
759 LocMapI.insert(LII->end, LStop, OldLocNo);
764 // Advance to the next overlap.
765 if (LII->end < LocMapI.stop()) {
768 LocMapI.advanceTo(LII->start);
771 if (!LocMapI.valid())
773 LII = LI->advanceTo(LII, LocMapI.start());
778 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
779 locations.erase(locations.begin() + OldLocNo);
781 while (LocMapI.valid()) {
782 unsigned v = LocMapI.value();
784 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
785 << LocMapI.stop() << ")\n");
789 LocMapI.setValueUnchecked(v-1);
794 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), 0);});
799 UserValue::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
800 bool DidChange = false;
801 // Split locations referring to OldReg. Iterate backwards so splitLocation can
802 // safely erase unuused locations.
803 for (unsigned i = locations.size(); i ; --i) {
804 unsigned LocNo = i-1;
805 const MachineOperand *Loc = &locations[LocNo];
806 if (!Loc->isReg() || Loc->getReg() != OldReg)
808 DidChange |= splitLocation(LocNo, NewRegs);
813 void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
814 bool DidChange = false;
815 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
816 DidChange |= UV->splitRegister(OldReg, NewRegs);
821 // Map all of the new virtual registers.
822 UserValue *UV = lookupVirtReg(OldReg);
823 for (unsigned i = 0; i != NewRegs.size(); ++i)
824 mapVirtReg(NewRegs[i]->reg, UV);
827 void LiveDebugVariables::
828 splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
830 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
834 UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
835 // Iterate over locations in reverse makes it easier to handle coalescing.
836 for (unsigned i = locations.size(); i ; --i) {
837 unsigned LocNo = i-1;
838 MachineOperand &Loc = locations[LocNo];
839 // Only virtual registers are rewritten.
840 if (!Loc.isReg() || !Loc.getReg() ||
841 !TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
843 unsigned VirtReg = Loc.getReg();
844 if (VRM.isAssignedReg(VirtReg) &&
845 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
846 // This can create a %noreg operand in rare cases when the sub-register
847 // index is no longer available. That means the user value is in a
848 // non-existent sub-register, and %noreg is exactly what we want.
849 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
850 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT &&
851 VRM.isSpillSlotUsed(VRM.getStackSlot(VirtReg))) {
852 // FIXME: Translate SubIdx to a stackslot offset.
853 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
858 coalesceLocation(LocNo);
862 /// findInsertLocation - Find an iterator for inserting a DBG_VALUE
864 static MachineBasicBlock::iterator
865 findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
866 LiveIntervals &LIS) {
867 SlotIndex Start = LIS.getMBBStartIdx(MBB);
868 Idx = Idx.getBaseIndex();
870 // Try to find an insert location by going backwards from Idx.
872 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
873 // We've reached the beginning of MBB.
875 MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
878 Idx = Idx.getPrevIndex();
881 // Don't insert anything after the first terminator, though.
882 return MI->getDesc().isTerminator() ? MBB->getFirstTerminator() :
883 llvm::next(MachineBasicBlock::iterator(MI));
886 DebugLoc UserValue::findDebugLoc() {
891 void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
894 const TargetInstrInfo &TII) {
895 MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
896 MachineOperand &Loc = locations[LocNo];
898 // Frame index locations may require a target callback.
900 MachineInstr *MI = TII.emitFrameIndexDebugValue(*MBB->getParent(),
901 Loc.getIndex(), offset, variable,
908 // This is not a frame index, or the target is happy with a standard FI.
909 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
910 .addOperand(Loc).addImm(offset).addMetadata(variable);
913 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
914 const TargetInstrInfo &TII) {
915 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
917 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
918 SlotIndex Start = I.start();
919 SlotIndex Stop = I.stop();
920 unsigned LocNo = I.value();
921 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
922 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
923 SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
925 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
926 insertDebugValue(MBB, Start, LocNo, LIS, TII);
928 // This interval may span multiple basic blocks.
929 // Insert a DBG_VALUE into each one.
930 while(Stop > MBBEnd) {
931 // Move to the next block.
935 MBBEnd = LIS.getMBBEndIdx(MBB);
936 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
937 insertDebugValue(MBB, Start, LocNo, LIS, TII);
939 DEBUG(dbgs() << '\n');
947 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
948 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
949 const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
950 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
951 DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
952 userValues[i]->rewriteLocations(*VRM, *TRI);
953 userValues[i]->emitDebugValues(VRM, *LIS, *TII);
957 void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
959 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
964 void LiveDebugVariables::dump() {
966 static_cast<LDVImpl*>(pImpl)->print(dbgs());