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 "llvm/ADT/IntervalMap.h"
25 #include "llvm/ADT/Statistic.h"
26 #include "llvm/CodeGen/LexicalScopes.h"
27 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
28 #include "llvm/CodeGen/MachineDominators.h"
29 #include "llvm/CodeGen/MachineFunction.h"
30 #include "llvm/CodeGen/MachineInstrBuilder.h"
31 #include "llvm/CodeGen/MachineRegisterInfo.h"
32 #include "llvm/CodeGen/Passes.h"
33 #include "llvm/CodeGen/VirtRegMap.h"
34 #include "llvm/DebugInfo.h"
35 #include "llvm/IR/Constants.h"
36 #include "llvm/IR/Metadata.h"
37 #include "llvm/IR/Value.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Target/TargetInstrInfo.h"
41 #include "llvm/Target/TargetMachine.h"
42 #include "llvm/Target/TargetRegisterInfo.h"
47 EnableLDV("live-debug-variables", cl::init(true),
48 cl::desc("Enable the live debug variables pass"), cl::Hidden);
50 STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted");
51 char LiveDebugVariables::ID = 0;
53 INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars",
54 "Debug Variable Analysis", false, false)
55 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
56 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
57 INITIALIZE_PASS_END(LiveDebugVariables, "livedebugvars",
58 "Debug Variable Analysis", false, false)
60 void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
61 AU.addRequired<MachineDominatorTree>();
62 AU.addRequiredTransitive<LiveIntervals>();
64 MachineFunctionPass::getAnalysisUsage(AU);
67 LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID), pImpl(0) {
68 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
71 /// LocMap - Map of where a user value is live, and its location.
72 typedef IntervalMap<SlotIndex, unsigned, 4> LocMap;
75 /// UserValueScopes - Keeps track of lexical scopes associated with an
76 /// user value's source location.
77 class UserValueScopes {
80 SmallPtrSet<const MachineBasicBlock *, 4> LBlocks;
83 UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(D), LS(L) {}
85 /// dominates - Return true if current scope dominates at least one machine
86 /// instruction in a given machine basic block.
87 bool dominates(MachineBasicBlock *MBB) {
89 LS.getMachineBasicBlocks(DL, LBlocks);
90 if (LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB))
95 } // end anonymous namespace
97 /// UserValue - A user value is a part of a debug info user variable.
99 /// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
100 /// holds part of a user variable. The part is identified by a byte offset.
102 /// UserValues are grouped into equivalence classes for easier searching. Two
103 /// user values are related if they refer to the same variable, or if they are
104 /// held by the same virtual register. The equivalence class is the transitive
105 /// closure of that relation.
109 const MDNode *variable; ///< The debug info variable we are part of.
110 unsigned offset; ///< Byte offset into variable.
111 DebugLoc dl; ///< The debug location for the variable. This is
112 ///< used by dwarf writer to find lexical scope.
113 UserValue *leader; ///< Equivalence class leader.
114 UserValue *next; ///< Next value in equivalence class, or null.
116 /// Numbered locations referenced by locmap.
117 SmallVector<MachineOperand, 4> locations;
119 /// Map of slot indices where this value is live.
122 /// coalesceLocation - After LocNo was changed, check if it has become
123 /// identical to another location, and coalesce them. This may cause LocNo or
124 /// a later location to be erased, but no earlier location will be erased.
125 void coalesceLocation(unsigned LocNo);
127 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
128 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
129 LiveIntervals &LIS, const TargetInstrInfo &TII);
131 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
132 /// is live. Returns true if any changes were made.
133 bool splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
136 /// UserValue - Create a new UserValue.
137 UserValue(const MDNode *var, unsigned o, DebugLoc L,
138 LocMap::Allocator &alloc)
139 : variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc)
142 /// getLeader - Get the leader of this value's equivalence class.
143 UserValue *getLeader() {
144 UserValue *l = leader;
145 while (l != l->leader)
150 /// getNext - Return the next UserValue in the equivalence class.
151 UserValue *getNext() const { return next; }
153 /// match - Does this UserValue match the parameters?
154 bool match(const MDNode *Var, unsigned Offset) const {
155 return Var == variable && Offset == offset;
158 /// merge - Merge equivalence classes.
159 static UserValue *merge(UserValue *L1, UserValue *L2) {
160 L2 = L2->getLeader();
163 L1 = L1->getLeader();
166 // Splice L2 before L1's members.
169 End->leader = L1, End = End->next;
171 End->next = L1->next;
176 /// getLocationNo - Return the location number that matches Loc.
177 unsigned getLocationNo(const MachineOperand &LocMO) {
179 if (LocMO.getReg() == 0)
181 // For register locations we dont care about use/def and other flags.
182 for (unsigned i = 0, e = locations.size(); i != e; ++i)
183 if (locations[i].isReg() &&
184 locations[i].getReg() == LocMO.getReg() &&
185 locations[i].getSubReg() == LocMO.getSubReg())
188 for (unsigned i = 0, e = locations.size(); i != e; ++i)
189 if (LocMO.isIdenticalTo(locations[i]))
191 locations.push_back(LocMO);
192 // We are storing a MachineOperand outside a MachineInstr.
193 locations.back().clearParent();
194 // Don't store def operands.
195 if (locations.back().isReg())
196 locations.back().setIsUse();
197 return locations.size() - 1;
200 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
201 void mapVirtRegs(LDVImpl *LDV);
203 /// addDef - Add a definition point to this value.
204 void addDef(SlotIndex Idx, const MachineOperand &LocMO) {
205 // Add a singular (Idx,Idx) -> Loc mapping.
206 LocMap::iterator I = locInts.find(Idx);
207 if (!I.valid() || I.start() != Idx)
208 I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO));
210 // A later DBG_VALUE at the same SlotIndex overrides the old location.
211 I.setValue(getLocationNo(LocMO));
214 /// extendDef - Extend the current definition as far as possible down the
215 /// dominator tree. Stop when meeting an existing def or when leaving the live
217 /// End points where VNI is no longer live are added to Kills.
218 /// @param Idx Starting point for the definition.
219 /// @param LocNo Location number to propagate.
220 /// @param LI Restrict liveness to where LI has the value VNI. May be null.
221 /// @param VNI When LI is not null, this is the value to restrict to.
222 /// @param Kills Append end points of VNI's live range to Kills.
223 /// @param LIS Live intervals analysis.
224 /// @param MDT Dominator tree.
225 void extendDef(SlotIndex Idx, unsigned LocNo,
226 LiveInterval *LI, const VNInfo *VNI,
227 SmallVectorImpl<SlotIndex> *Kills,
228 LiveIntervals &LIS, MachineDominatorTree &MDT,
229 UserValueScopes &UVS);
231 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
232 /// registers. Determine if any of the copies are available at the kill
233 /// points, and add defs if possible.
234 /// @param LI Scan for copies of the value in LI->reg.
235 /// @param LocNo Location number of LI->reg.
236 /// @param Kills Points where the range of LocNo could be extended.
237 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
238 void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
239 const SmallVectorImpl<SlotIndex> &Kills,
240 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
241 MachineRegisterInfo &MRI,
244 /// computeIntervals - Compute the live intervals of all locations after
245 /// collecting all their def points.
246 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
247 LiveIntervals &LIS, MachineDominatorTree &MDT,
248 UserValueScopes &UVS);
250 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
251 /// live. Returns true if any changes were made.
252 bool splitRegister(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
254 /// rewriteLocations - Rewrite virtual register locations according to the
255 /// provided virtual register map.
256 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
258 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
259 void emitDebugValues(VirtRegMap *VRM,
260 LiveIntervals &LIS, const TargetInstrInfo &TRI);
262 /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
263 /// variable may have more than one corresponding DBG_VALUE instructions.
264 /// Only first one needs DebugLoc to identify variable's lexical scope
266 DebugLoc findDebugLoc();
268 /// getDebugLoc - Return DebugLoc of this UserValue.
269 DebugLoc getDebugLoc() { return dl;}
270 void print(raw_ostream&, const TargetMachine*);
274 /// LDVImpl - Implementation of the LiveDebugVariables pass.
277 LiveDebugVariables &pass;
278 LocMap::Allocator allocator;
282 MachineDominatorTree *MDT;
283 const TargetRegisterInfo *TRI;
285 /// Whether emitDebugValues is called.
287 /// Whether the machine function is modified during the pass.
290 /// userValues - All allocated UserValue instances.
291 SmallVector<UserValue*, 8> userValues;
293 /// Map virtual register to eq class leader.
294 typedef DenseMap<unsigned, UserValue*> VRMap;
295 VRMap virtRegToEqClass;
297 /// Map user variable to eq class leader.
298 typedef DenseMap<const MDNode *, UserValue*> UVMap;
301 /// getUserValue - Find or create a UserValue.
302 UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL);
304 /// lookupVirtReg - Find the EC leader for VirtReg or null.
305 UserValue *lookupVirtReg(unsigned VirtReg);
307 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
308 /// @param MI DBG_VALUE instruction
309 /// @param Idx Last valid SLotIndex before instruction.
310 /// @return True if the DBG_VALUE instruction should be deleted.
311 bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
313 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
314 /// a UserValue def for each instruction.
315 /// @param mf MachineFunction to be scanned.
316 /// @return True if any debug values were found.
317 bool collectDebugValues(MachineFunction &mf);
319 /// computeIntervals - Compute the live intervals of all user values after
320 /// collecting all their def points.
321 void computeIntervals();
324 LDVImpl(LiveDebugVariables *ps) : pass(*ps), EmitDone(false),
326 bool runOnMachineFunction(MachineFunction &mf);
328 /// clear - Release all memory.
330 DeleteContainerPointers(userValues);
332 virtRegToEqClass.clear();
334 // Make sure we call emitDebugValues if the machine function was modified.
335 assert((!ModifiedMF || EmitDone) &&
336 "Dbg values are not emitted in LDV");
341 /// mapVirtReg - Map virtual register to an equivalence class.
342 void mapVirtReg(unsigned VirtReg, UserValue *EC);
344 /// splitRegister - Replace all references to OldReg with NewRegs.
345 void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs);
347 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
348 void emitDebugValues(VirtRegMap *VRM);
350 void print(raw_ostream&);
354 void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
355 DIVariable DV(variable);
357 DV.printExtendedName(OS);
361 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
362 OS << " [" << I.start() << ';' << I.stop() << "):";
363 if (I.value() == ~0u)
368 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
369 OS << " Loc" << i << '=';
370 locations[i].print(OS, TM);
375 void LDVImpl::print(raw_ostream &OS) {
376 OS << "********** DEBUG VARIABLES **********\n";
377 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
378 userValues[i]->print(OS, &MF->getTarget());
381 void UserValue::coalesceLocation(unsigned LocNo) {
382 unsigned KeepLoc = 0;
383 for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
384 if (KeepLoc == LocNo)
386 if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
390 if (KeepLoc == locations.size())
393 // Keep the smaller location, erase the larger one.
394 unsigned EraseLoc = LocNo;
395 if (KeepLoc > EraseLoc)
396 std::swap(KeepLoc, EraseLoc);
397 locations.erase(locations.begin() + EraseLoc);
400 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
401 unsigned v = I.value();
403 I.setValue(KeepLoc); // Coalesce when possible.
404 else if (v > EraseLoc)
405 I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
409 void UserValue::mapVirtRegs(LDVImpl *LDV) {
410 for (unsigned i = 0, e = locations.size(); i != e; ++i)
411 if (locations[i].isReg() &&
412 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
413 LDV->mapVirtReg(locations[i].getReg(), this);
416 UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
418 UserValue *&Leader = userVarMap[Var];
420 UserValue *UV = Leader->getLeader();
422 for (; UV; UV = UV->getNext())
423 if (UV->match(Var, Offset))
427 UserValue *UV = new UserValue(Var, Offset, DL, allocator);
428 userValues.push_back(UV);
429 Leader = UserValue::merge(Leader, UV);
433 void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
434 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
435 UserValue *&Leader = virtRegToEqClass[VirtReg];
436 Leader = UserValue::merge(Leader, EC);
439 UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
440 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
441 return UV->getLeader();
445 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
446 // DBG_VALUE loc, offset, variable
447 if (MI->getNumOperands() != 3 ||
448 !MI->getOperand(1).isImm() || !MI->getOperand(2).isMetadata()) {
449 DEBUG(dbgs() << "Can't handle " << *MI);
453 // Get or create the UserValue for (variable,offset).
454 unsigned Offset = MI->getOperand(1).getImm();
455 const MDNode *Var = MI->getOperand(2).getMetadata();
456 UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc());
457 UV->addDef(Idx, MI->getOperand(0));
461 bool LDVImpl::collectDebugValues(MachineFunction &mf) {
462 bool Changed = false;
463 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
465 MachineBasicBlock *MBB = MFI;
466 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
468 if (!MBBI->isDebugValue()) {
472 // DBG_VALUE has no slot index, use the previous instruction instead.
473 SlotIndex Idx = MBBI == MBB->begin() ?
474 LIS->getMBBStartIdx(MBB) :
475 LIS->getInstructionIndex(llvm::prior(MBBI)).getRegSlot();
476 // Handle consecutive DBG_VALUE instructions with the same slot index.
478 if (handleDebugValue(MBBI, Idx)) {
479 MBBI = MBB->erase(MBBI);
483 } while (MBBI != MBBE && MBBI->isDebugValue());
489 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
490 LiveInterval *LI, const VNInfo *VNI,
491 SmallVectorImpl<SlotIndex> *Kills,
492 LiveIntervals &LIS, MachineDominatorTree &MDT,
493 UserValueScopes &UVS) {
494 SmallVector<SlotIndex, 16> Todo;
497 SlotIndex Start = Todo.pop_back_val();
498 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
499 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
500 LocMap::iterator I = locInts.find(Start);
502 // Limit to VNI's live range.
505 LiveRange *Range = LI->getLiveRangeContaining(Start);
506 if (!Range || Range->valno != VNI) {
508 Kills->push_back(Start);
511 if (Range->end < Stop)
512 Stop = Range->end, ToEnd = false;
515 // There could already be a short def at Start.
516 if (I.valid() && I.start() <= Start) {
517 // Stop when meeting a different location or an already extended interval.
518 Start = Start.getNextSlot();
519 if (I.value() != LocNo || I.stop() != Start)
521 // This is a one-slot placeholder. Just skip it.
525 // Limited by the next def.
526 if (I.valid() && I.start() < Stop)
527 Stop = I.start(), ToEnd = false;
528 // Limited by VNI's live range.
529 else if (!ToEnd && Kills)
530 Kills->push_back(Stop);
535 I.insert(Start, Stop, LocNo);
537 // If we extended to the MBB end, propagate down the dominator tree.
540 const std::vector<MachineDomTreeNode*> &Children =
541 MDT.getNode(MBB)->getChildren();
542 for (unsigned i = 0, e = Children.size(); i != e; ++i) {
543 MachineBasicBlock *MBB = Children[i]->getBlock();
544 if (UVS.dominates(MBB))
545 Todo.push_back(LIS.getMBBStartIdx(MBB));
547 } while (!Todo.empty());
551 UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
552 const SmallVectorImpl<SlotIndex> &Kills,
553 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
554 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
557 // Don't track copies from physregs, there are too many uses.
558 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
561 // Collect all the (vreg, valno) pairs that are copies of LI.
562 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
563 for (MachineRegisterInfo::use_nodbg_iterator
564 UI = MRI.use_nodbg_begin(LI->reg),
565 UE = MRI.use_nodbg_end(); UI != UE; ++UI) {
566 // Copies of the full value.
567 if (UI.getOperand().getSubReg() || !UI->isCopy())
569 MachineInstr *MI = &*UI;
570 unsigned DstReg = MI->getOperand(0).getReg();
572 // Don't follow copies to physregs. These are usually setting up call
573 // arguments, and the argument registers are always call clobbered. We are
574 // better off in the source register which could be a callee-saved register,
575 // or it could be spilled.
576 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
579 // Is LocNo extended to reach this copy? If not, another def may be blocking
580 // it, or we are looking at a wrong value of LI.
581 SlotIndex Idx = LIS.getInstructionIndex(MI);
582 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
583 if (!I.valid() || I.value() != LocNo)
586 if (!LIS.hasInterval(DstReg))
588 LiveInterval *DstLI = &LIS.getInterval(DstReg);
589 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
590 assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value");
591 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
594 if (CopyValues.empty())
597 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
599 // Try to add defs of the copied values for each kill point.
600 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
601 SlotIndex Idx = Kills[i];
602 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
603 LiveInterval *DstLI = CopyValues[j].first;
604 const VNInfo *DstVNI = CopyValues[j].second;
605 if (DstLI->getVNInfoAt(Idx) != DstVNI)
607 // Check that there isn't already a def at Idx
608 LocMap::iterator I = locInts.find(Idx);
609 if (I.valid() && I.start() <= Idx)
611 DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
612 << DstVNI->id << " in " << *DstLI << '\n');
613 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
614 assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
615 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
616 I.insert(Idx, Idx.getNextSlot(), LocNo);
617 NewDefs.push_back(std::make_pair(Idx, LocNo));
624 UserValue::computeIntervals(MachineRegisterInfo &MRI,
625 const TargetRegisterInfo &TRI,
627 MachineDominatorTree &MDT,
628 UserValueScopes &UVS) {
629 SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
631 // Collect all defs to be extended (Skipping undefs).
632 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
633 if (I.value() != ~0u)
634 Defs.push_back(std::make_pair(I.start(), I.value()));
636 // Extend all defs, and possibly add new ones along the way.
637 for (unsigned i = 0; i != Defs.size(); ++i) {
638 SlotIndex Idx = Defs[i].first;
639 unsigned LocNo = Defs[i].second;
640 const MachineOperand &Loc = locations[LocNo];
643 extendDef(Idx, LocNo, 0, 0, 0, LIS, MDT, UVS);
647 // Register locations are constrained to where the register value is live.
648 if (TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
649 LiveInterval *LI = 0;
650 const VNInfo *VNI = 0;
651 if (LIS.hasInterval(Loc.getReg())) {
652 LI = &LIS.getInterval(Loc.getReg());
653 VNI = LI->getVNInfoAt(Idx);
655 SmallVector<SlotIndex, 16> Kills;
656 extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS);
658 addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
662 // For physregs, use the live range of the first regunit as a guide.
663 unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
664 LiveInterval *LI = &LIS.getRegUnit(Unit);
665 const VNInfo *VNI = LI->getVNInfoAt(Idx);
666 // Don't track copies from physregs, it is too expensive.
667 extendDef(Idx, LocNo, LI, VNI, 0, LIS, MDT, UVS);
670 // Finally, erase all the undefs.
671 for (LocMap::iterator I = locInts.begin(); I.valid();)
672 if (I.value() == ~0u)
678 void LDVImpl::computeIntervals() {
679 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
680 UserValueScopes UVS(userValues[i]->getDebugLoc(), LS);
681 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, *MDT, UVS);
682 userValues[i]->mapVirtRegs(this);
686 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
688 LIS = &pass.getAnalysis<LiveIntervals>();
689 MDT = &pass.getAnalysis<MachineDominatorTree>();
690 TRI = mf.getTarget().getRegisterInfo();
693 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
694 << mf.getName() << " **********\n");
696 bool Changed = collectDebugValues(mf);
698 DEBUG(print(dbgs()));
700 ModifiedMF = Changed;
704 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
708 pImpl = new LDVImpl(this);
709 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
712 void LiveDebugVariables::releaseMemory() {
714 static_cast<LDVImpl*>(pImpl)->clear();
717 LiveDebugVariables::~LiveDebugVariables() {
719 delete static_cast<LDVImpl*>(pImpl);
722 //===----------------------------------------------------------------------===//
723 // Live Range Splitting
724 //===----------------------------------------------------------------------===//
727 UserValue::splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs) {
729 dbgs() << "Splitting Loc" << OldLocNo << '\t';
732 bool DidChange = false;
733 LocMap::iterator LocMapI;
734 LocMapI.setMap(locInts);
735 for (unsigned i = 0; i != NewRegs.size(); ++i) {
736 LiveInterval *LI = NewRegs[i];
740 // Don't allocate the new LocNo until it is needed.
741 unsigned NewLocNo = ~0u;
743 // Iterate over the overlaps between locInts and LI.
744 LocMapI.find(LI->beginIndex());
745 if (!LocMapI.valid())
747 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
748 LiveInterval::iterator LIE = LI->end();
749 while (LocMapI.valid() && LII != LIE) {
750 // At this point, we know that LocMapI.stop() > LII->start.
751 LII = LI->advanceTo(LII, LocMapI.start());
755 // Now LII->end > LocMapI.start(). Do we have an overlap?
756 if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
757 // Overlapping correct location. Allocate NewLocNo now.
758 if (NewLocNo == ~0u) {
759 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
760 MO.setSubReg(locations[OldLocNo].getSubReg());
761 NewLocNo = getLocationNo(MO);
765 SlotIndex LStart = LocMapI.start();
766 SlotIndex LStop = LocMapI.stop();
768 // Trim LocMapI down to the LII overlap.
769 if (LStart < LII->start)
770 LocMapI.setStartUnchecked(LII->start);
771 if (LStop > LII->end)
772 LocMapI.setStopUnchecked(LII->end);
774 // Change the value in the overlap. This may trigger coalescing.
775 LocMapI.setValue(NewLocNo);
777 // Re-insert any removed OldLocNo ranges.
778 if (LStart < LocMapI.start()) {
779 LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
781 assert(LocMapI.valid() && "Unexpected coalescing");
783 if (LStop > LocMapI.stop()) {
785 LocMapI.insert(LII->end, LStop, OldLocNo);
790 // Advance to the next overlap.
791 if (LII->end < LocMapI.stop()) {
794 LocMapI.advanceTo(LII->start);
797 if (!LocMapI.valid())
799 LII = LI->advanceTo(LII, LocMapI.start());
804 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
805 locations.erase(locations.begin() + OldLocNo);
807 while (LocMapI.valid()) {
808 unsigned v = LocMapI.value();
810 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
811 << LocMapI.stop() << ")\n");
815 LocMapI.setValueUnchecked(v-1);
820 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), 0);});
825 UserValue::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
826 bool DidChange = false;
827 // Split locations referring to OldReg. Iterate backwards so splitLocation can
828 // safely erase unused locations.
829 for (unsigned i = locations.size(); i ; --i) {
830 unsigned LocNo = i-1;
831 const MachineOperand *Loc = &locations[LocNo];
832 if (!Loc->isReg() || Loc->getReg() != OldReg)
834 DidChange |= splitLocation(LocNo, NewRegs);
839 void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
840 bool DidChange = false;
841 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
842 DidChange |= UV->splitRegister(OldReg, NewRegs);
847 // Map all of the new virtual registers.
848 UserValue *UV = lookupVirtReg(OldReg);
849 for (unsigned i = 0; i != NewRegs.size(); ++i)
850 mapVirtReg(NewRegs[i]->reg, UV);
853 void LiveDebugVariables::
854 splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
856 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
860 UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
861 // Iterate over locations in reverse makes it easier to handle coalescing.
862 for (unsigned i = locations.size(); i ; --i) {
863 unsigned LocNo = i-1;
864 MachineOperand &Loc = locations[LocNo];
865 // Only virtual registers are rewritten.
866 if (!Loc.isReg() || !Loc.getReg() ||
867 !TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
869 unsigned VirtReg = Loc.getReg();
870 if (VRM.isAssignedReg(VirtReg) &&
871 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
872 // This can create a %noreg operand in rare cases when the sub-register
873 // index is no longer available. That means the user value is in a
874 // non-existent sub-register, and %noreg is exactly what we want.
875 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
876 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
877 // FIXME: Translate SubIdx to a stackslot offset.
878 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
883 coalesceLocation(LocNo);
887 /// findInsertLocation - Find an iterator for inserting a DBG_VALUE
889 static MachineBasicBlock::iterator
890 findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
891 LiveIntervals &LIS) {
892 SlotIndex Start = LIS.getMBBStartIdx(MBB);
893 Idx = Idx.getBaseIndex();
895 // Try to find an insert location by going backwards from Idx.
897 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
898 // We've reached the beginning of MBB.
900 MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
903 Idx = Idx.getPrevIndex();
906 // Don't insert anything after the first terminator, though.
907 return MI->isTerminator() ? MBB->getFirstTerminator() :
908 llvm::next(MachineBasicBlock::iterator(MI));
911 DebugLoc UserValue::findDebugLoc() {
916 void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
919 const TargetInstrInfo &TII) {
920 MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
921 MachineOperand &Loc = locations[LocNo];
922 ++NumInsertedDebugValues;
924 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
925 .addOperand(Loc).addImm(offset).addMetadata(variable);
928 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
929 const TargetInstrInfo &TII) {
930 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
932 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
933 SlotIndex Start = I.start();
934 SlotIndex Stop = I.stop();
935 unsigned LocNo = I.value();
936 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
937 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
938 SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
940 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
941 insertDebugValue(MBB, Start, LocNo, LIS, TII);
942 // This interval may span multiple basic blocks.
943 // Insert a DBG_VALUE into each one.
944 while(Stop > MBBEnd) {
945 // Move to the next block.
949 MBBEnd = LIS.getMBBEndIdx(MBB);
950 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
951 insertDebugValue(MBB, Start, LocNo, LIS, TII);
953 DEBUG(dbgs() << '\n');
961 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
962 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
963 const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
964 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
965 DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
966 userValues[i]->rewriteLocations(*VRM, *TRI);
967 userValues[i]->emitDebugValues(VRM, *LIS, *TII);
972 void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
974 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
979 void LiveDebugVariables::dump() {
981 static_cast<LDVImpl*>(pImpl)->print(dbgs());