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/Analysis/DebugInfo.h"
29 #include "llvm/ADT/IntervalMap.h"
30 #include "llvm/ADT/Statistic.h"
31 #include "llvm/CodeGen/LexicalScopes.h"
32 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
33 #include "llvm/CodeGen/MachineDominators.h"
34 #include "llvm/CodeGen/MachineFunction.h"
35 #include "llvm/CodeGen/MachineInstrBuilder.h"
36 #include "llvm/CodeGen/MachineRegisterInfo.h"
37 #include "llvm/CodeGen/Passes.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;
74 /// UserValueScopes - Keeps track of lexical scopes associated with an
75 /// user value's source location.
76 class UserValueScopes {
79 SmallPtrSet<const MachineBasicBlock *, 4> LBlocks;
82 UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(D), LS(L) {}
84 /// dominates - Return true if current scope dominates at least one machine
85 /// instruction in a given machine basic block.
86 bool dominates(MachineBasicBlock *MBB) {
88 LS.getMachineBasicBlocks(DL, LBlocks);
89 if (LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB))
95 /// UserValue - A user value is a part of a debug info user variable.
97 /// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
98 /// holds part of a user variable. The part is identified by a byte offset.
100 /// UserValues are grouped into equivalence classes for easier searching. Two
101 /// user values are related if they refer to the same variable, or if they are
102 /// held by the same virtual register. The equivalence class is the transitive
103 /// closure of that relation.
107 const MDNode *variable; ///< The debug info variable we are part of.
108 unsigned offset; ///< Byte offset into variable.
109 DebugLoc dl; ///< The debug location for the variable. This is
110 ///< used by dwarf writer to find lexical scope.
111 UserValue *leader; ///< Equivalence class leader.
112 UserValue *next; ///< Next value in equivalence class, or null.
114 /// Numbered locations referenced by locmap.
115 SmallVector<MachineOperand, 4> locations;
117 /// Map of slot indices where this value is live.
120 /// coalesceLocation - After LocNo was changed, check if it has become
121 /// identical to another location, and coalesce them. This may cause LocNo or
122 /// a later location to be erased, but no earlier location will be erased.
123 void coalesceLocation(unsigned LocNo);
125 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
126 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
127 LiveIntervals &LIS, const TargetInstrInfo &TII);
129 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
130 /// is live. Returns true if any changes were made.
131 bool splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
134 /// UserValue - Create a new UserValue.
135 UserValue(const MDNode *var, unsigned o, DebugLoc L,
136 LocMap::Allocator &alloc)
137 : variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc)
140 /// getLeader - Get the leader of this value's equivalence class.
141 UserValue *getLeader() {
142 UserValue *l = leader;
143 while (l != l->leader)
148 /// getNext - Return the next UserValue in the equivalence class.
149 UserValue *getNext() const { return next; }
151 /// match - Does this UserValue match the parameters?
152 bool match(const MDNode *Var, unsigned Offset) const {
153 return Var == variable && Offset == offset;
156 /// merge - Merge equivalence classes.
157 static UserValue *merge(UserValue *L1, UserValue *L2) {
158 L2 = L2->getLeader();
161 L1 = L1->getLeader();
164 // Splice L2 before L1's members.
167 End->leader = L1, End = End->next;
169 End->next = L1->next;
174 /// getLocationNo - Return the location number that matches Loc.
175 unsigned getLocationNo(const MachineOperand &LocMO) {
177 if (LocMO.getReg() == 0)
179 // For register locations we dont care about use/def and other flags.
180 for (unsigned i = 0, e = locations.size(); i != e; ++i)
181 if (locations[i].isReg() &&
182 locations[i].getReg() == LocMO.getReg() &&
183 locations[i].getSubReg() == LocMO.getSubReg())
186 for (unsigned i = 0, e = locations.size(); i != e; ++i)
187 if (LocMO.isIdenticalTo(locations[i]))
189 locations.push_back(LocMO);
190 // We are storing a MachineOperand outside a MachineInstr.
191 locations.back().clearParent();
192 // Don't store def operands.
193 if (locations.back().isReg())
194 locations.back().setIsUse();
195 return locations.size() - 1;
198 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
199 void mapVirtRegs(LDVImpl *LDV);
201 /// addDef - Add a definition point to this value.
202 void addDef(SlotIndex Idx, const MachineOperand &LocMO) {
203 // Add a singular (Idx,Idx) -> Loc mapping.
204 LocMap::iterator I = locInts.find(Idx);
205 if (!I.valid() || I.start() != Idx)
206 I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO));
208 // A later DBG_VALUE at the same SlotIndex overrides the old location.
209 I.setValue(getLocationNo(LocMO));
212 /// extendDef - Extend the current definition as far as possible down the
213 /// dominator tree. Stop when meeting an existing def or when leaving the live
215 /// End points where VNI is no longer live are added to Kills.
216 /// @param Idx Starting point for the definition.
217 /// @param LocNo Location number to propagate.
218 /// @param LI Restrict liveness to where LI has the value VNI. May be null.
219 /// @param VNI When LI is not null, this is the value to restrict to.
220 /// @param Kills Append end points of VNI's live range to Kills.
221 /// @param LIS Live intervals analysis.
222 /// @param MDT Dominator tree.
223 void extendDef(SlotIndex Idx, unsigned LocNo,
224 LiveInterval *LI, const VNInfo *VNI,
225 SmallVectorImpl<SlotIndex> *Kills,
226 LiveIntervals &LIS, MachineDominatorTree &MDT,
227 UserValueScopes &UVS);
229 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
230 /// registers. Determine if any of the copies are available at the kill
231 /// points, and add defs if possible.
232 /// @param LI Scan for copies of the value in LI->reg.
233 /// @param LocNo Location number of LI->reg.
234 /// @param Kills Points where the range of LocNo could be extended.
235 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
236 void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
237 const SmallVectorImpl<SlotIndex> &Kills,
238 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
239 MachineRegisterInfo &MRI,
242 /// computeIntervals - Compute the live intervals of all locations after
243 /// collecting all their def points.
244 void computeIntervals(MachineRegisterInfo &MRI,
245 LiveIntervals &LIS, MachineDominatorTree &MDT,
246 UserValueScopes &UVS);
248 /// renameRegister - Update locations to rewrite OldReg as NewReg:SubIdx.
249 void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
250 const TargetRegisterInfo *TRI);
252 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
253 /// live. Returns true if any changes were made.
254 bool splitRegister(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
256 /// rewriteLocations - Rewrite virtual register locations according to the
257 /// provided virtual register map.
258 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
260 /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
261 void emitDebugValues(VirtRegMap *VRM,
262 LiveIntervals &LIS, const TargetInstrInfo &TRI);
264 /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
265 /// variable may have more than one corresponding DBG_VALUE instructions.
266 /// Only first one needs DebugLoc to identify variable's lexical scope
268 DebugLoc findDebugLoc();
270 /// getDebugLoc - Return DebugLoc of this UserValue.
271 DebugLoc getDebugLoc() { return dl;}
272 void print(raw_ostream&, const TargetMachine*);
276 /// LDVImpl - Implementation of the LiveDebugVariables pass.
279 LiveDebugVariables &pass;
280 LocMap::Allocator allocator;
284 MachineDominatorTree *MDT;
285 const TargetRegisterInfo *TRI;
287 /// userValues - All allocated UserValue instances.
288 SmallVector<UserValue*, 8> userValues;
290 /// Map virtual register to eq class leader.
291 typedef DenseMap<unsigned, UserValue*> VRMap;
292 VRMap virtRegToEqClass;
294 /// Map user variable to eq class leader.
295 typedef DenseMap<const MDNode *, UserValue*> UVMap;
298 /// getUserValue - Find or create a UserValue.
299 UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL);
301 /// lookupVirtReg - Find the EC leader for VirtReg or null.
302 UserValue *lookupVirtReg(unsigned VirtReg);
304 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
305 /// @param MI DBG_VALUE instruction
306 /// @param Idx Last valid SLotIndex before instruction.
307 /// @return True if the DBG_VALUE instruction should be deleted.
308 bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
310 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
311 /// a UserValue def for each instruction.
312 /// @param mf MachineFunction to be scanned.
313 /// @return True if any debug values were found.
314 bool collectDebugValues(MachineFunction &mf);
316 /// computeIntervals - Compute the live intervals of all user values after
317 /// collecting all their def points.
318 void computeIntervals();
321 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
322 bool runOnMachineFunction(MachineFunction &mf);
324 /// clear - Relase all memory.
326 DeleteContainerPointers(userValues);
328 virtRegToEqClass.clear();
332 /// mapVirtReg - Map virtual register to an equivalence class.
333 void mapVirtReg(unsigned VirtReg, UserValue *EC);
335 /// renameRegister - Replace all references to OldReg with NewReg:SubIdx.
336 void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
338 /// splitRegister - Replace all references to OldReg with NewRegs.
339 void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs);
341 /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
342 void emitDebugValues(VirtRegMap *VRM);
344 void print(raw_ostream&);
348 void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
349 DIVariable DV(variable);
351 DV.printExtendedName(OS);
355 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
356 OS << " [" << I.start() << ';' << I.stop() << "):";
357 if (I.value() == ~0u)
362 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
363 OS << " Loc" << i << '=';
364 locations[i].print(OS, TM);
369 void LDVImpl::print(raw_ostream &OS) {
370 OS << "********** DEBUG VARIABLES **********\n";
371 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
372 userValues[i]->print(OS, &MF->getTarget());
375 void UserValue::coalesceLocation(unsigned LocNo) {
376 unsigned KeepLoc = 0;
377 for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
378 if (KeepLoc == LocNo)
380 if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
384 if (KeepLoc == locations.size())
387 // Keep the smaller location, erase the larger one.
388 unsigned EraseLoc = LocNo;
389 if (KeepLoc > EraseLoc)
390 std::swap(KeepLoc, EraseLoc);
391 locations.erase(locations.begin() + EraseLoc);
394 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
395 unsigned v = I.value();
397 I.setValue(KeepLoc); // Coalesce when possible.
398 else if (v > EraseLoc)
399 I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
403 void UserValue::mapVirtRegs(LDVImpl *LDV) {
404 for (unsigned i = 0, e = locations.size(); i != e; ++i)
405 if (locations[i].isReg() &&
406 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
407 LDV->mapVirtReg(locations[i].getReg(), this);
410 UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
412 UserValue *&Leader = userVarMap[Var];
414 UserValue *UV = Leader->getLeader();
416 for (; UV; UV = UV->getNext())
417 if (UV->match(Var, Offset))
421 UserValue *UV = new UserValue(Var, Offset, DL, allocator);
422 userValues.push_back(UV);
423 Leader = UserValue::merge(Leader, UV);
427 void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
428 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
429 UserValue *&Leader = virtRegToEqClass[VirtReg];
430 Leader = UserValue::merge(Leader, EC);
433 UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
434 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
435 return UV->getLeader();
439 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
440 // DBG_VALUE loc, offset, variable
441 if (MI->getNumOperands() != 3 ||
442 !MI->getOperand(1).isImm() || !MI->getOperand(2).isMetadata()) {
443 DEBUG(dbgs() << "Can't handle " << *MI);
447 // Get or create the UserValue for (variable,offset).
448 unsigned Offset = MI->getOperand(1).getImm();
449 const MDNode *Var = MI->getOperand(2).getMetadata();
450 UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc());
451 UV->addDef(Idx, MI->getOperand(0));
455 bool LDVImpl::collectDebugValues(MachineFunction &mf) {
456 bool Changed = false;
457 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
459 MachineBasicBlock *MBB = MFI;
460 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
462 if (!MBBI->isDebugValue()) {
466 // DBG_VALUE has no slot index, use the previous instruction instead.
467 SlotIndex Idx = MBBI == MBB->begin() ?
468 LIS->getMBBStartIdx(MBB) :
469 LIS->getInstructionIndex(llvm::prior(MBBI)).getDefIndex();
470 // Handle consecutive DBG_VALUE instructions with the same slot index.
472 if (handleDebugValue(MBBI, Idx)) {
473 MBBI = MBB->erase(MBBI);
477 } while (MBBI != MBBE && MBBI->isDebugValue());
483 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
484 LiveInterval *LI, const VNInfo *VNI,
485 SmallVectorImpl<SlotIndex> *Kills,
486 LiveIntervals &LIS, MachineDominatorTree &MDT,
487 UserValueScopes &UVS) {
488 SmallVector<SlotIndex, 16> Todo;
491 SlotIndex Start = Todo.pop_back_val();
492 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
493 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
494 LocMap::iterator I = locInts.find(Start);
496 // Limit to VNI's live range.
499 LiveRange *Range = LI->getLiveRangeContaining(Start);
500 if (!Range || Range->valno != VNI) {
502 Kills->push_back(Start);
505 if (Range->end < Stop)
506 Stop = Range->end, ToEnd = false;
509 // There could already be a short def at Start.
510 if (I.valid() && I.start() <= Start) {
511 // Stop when meeting a different location or an already extended interval.
512 Start = Start.getNextSlot();
513 if (I.value() != LocNo || I.stop() != Start)
515 // This is a one-slot placeholder. Just skip it.
519 // Limited by the next def.
520 if (I.valid() && I.start() < Stop)
521 Stop = I.start(), ToEnd = false;
522 // Limited by VNI's live range.
523 else if (!ToEnd && Kills)
524 Kills->push_back(Stop);
529 I.insert(Start, Stop, LocNo);
531 // If we extended to the MBB end, propagate down the dominator tree.
534 const std::vector<MachineDomTreeNode*> &Children =
535 MDT.getNode(MBB)->getChildren();
536 for (unsigned i = 0, e = Children.size(); i != e; ++i) {
537 MachineBasicBlock *MBB = Children[i]->getBlock();
538 if (UVS.dominates(MBB))
539 Todo.push_back(LIS.getMBBStartIdx(MBB));
541 } while (!Todo.empty());
545 UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
546 const SmallVectorImpl<SlotIndex> &Kills,
547 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
548 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
551 // Don't track copies from physregs, there are too many uses.
552 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
555 // Collect all the (vreg, valno) pairs that are copies of LI.
556 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
557 for (MachineRegisterInfo::use_nodbg_iterator
558 UI = MRI.use_nodbg_begin(LI->reg),
559 UE = MRI.use_nodbg_end(); UI != UE; ++UI) {
560 // Copies of the full value.
561 if (UI.getOperand().getSubReg() || !UI->isCopy())
563 MachineInstr *MI = &*UI;
564 unsigned DstReg = MI->getOperand(0).getReg();
566 // Don't follow copies to physregs. These are usually setting up call
567 // arguments, and the argument registers are always call clobbered. We are
568 // better off in the source register which could be a callee-saved register,
569 // or it could be spilled.
570 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
573 // Is LocNo extended to reach this copy? If not, another def may be blocking
574 // it, or we are looking at a wrong value of LI.
575 SlotIndex Idx = LIS.getInstructionIndex(MI);
576 LocMap::iterator I = locInts.find(Idx.getUseIndex());
577 if (!I.valid() || I.value() != LocNo)
580 if (!LIS.hasInterval(DstReg))
582 LiveInterval *DstLI = &LIS.getInterval(DstReg);
583 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getDefIndex());
584 assert(DstVNI && DstVNI->def == Idx.getDefIndex() && "Bad copy value");
585 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
588 if (CopyValues.empty())
591 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
593 // Try to add defs of the copied values for each kill point.
594 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
595 SlotIndex Idx = Kills[i];
596 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
597 LiveInterval *DstLI = CopyValues[j].first;
598 const VNInfo *DstVNI = CopyValues[j].second;
599 if (DstLI->getVNInfoAt(Idx) != DstVNI)
601 // Check that there isn't already a def at Idx
602 LocMap::iterator I = locInts.find(Idx);
603 if (I.valid() && I.start() <= Idx)
605 DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
606 << DstVNI->id << " in " << *DstLI << '\n');
607 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
608 assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
609 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
610 I.insert(Idx, Idx.getNextSlot(), LocNo);
611 NewDefs.push_back(std::make_pair(Idx, LocNo));
618 UserValue::computeIntervals(MachineRegisterInfo &MRI,
620 MachineDominatorTree &MDT,
621 UserValueScopes &UVS) {
622 SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
624 // Collect all defs to be extended (Skipping undefs).
625 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
626 if (I.value() != ~0u)
627 Defs.push_back(std::make_pair(I.start(), I.value()));
629 // Extend all defs, and possibly add new ones along the way.
630 for (unsigned i = 0; i != Defs.size(); ++i) {
631 SlotIndex Idx = Defs[i].first;
632 unsigned LocNo = Defs[i].second;
633 const MachineOperand &Loc = locations[LocNo];
635 // Register locations are constrained to where the register value is live.
636 if (Loc.isReg() && LIS.hasInterval(Loc.getReg())) {
637 LiveInterval *LI = &LIS.getInterval(Loc.getReg());
638 const VNInfo *VNI = LI->getVNInfoAt(Idx);
639 SmallVector<SlotIndex, 16> Kills;
640 extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS);
641 addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
643 extendDef(Idx, LocNo, 0, 0, 0, LIS, MDT, UVS);
646 // Finally, erase all the undefs.
647 for (LocMap::iterator I = locInts.begin(); I.valid();)
648 if (I.value() == ~0u)
654 void LDVImpl::computeIntervals() {
655 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
656 UserValueScopes UVS(userValues[i]->getDebugLoc(), LS);
657 userValues[i]->computeIntervals(MF->getRegInfo(), *LIS, *MDT, UVS);
658 userValues[i]->mapVirtRegs(this);
662 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
664 LIS = &pass.getAnalysis<LiveIntervals>();
665 MDT = &pass.getAnalysis<MachineDominatorTree>();
666 TRI = mf.getTarget().getRegisterInfo();
669 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
670 << ((Value*)mf.getFunction())->getName()
673 bool Changed = collectDebugValues(mf);
675 DEBUG(print(dbgs()));
680 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
684 pImpl = new LDVImpl(this);
685 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
688 void LiveDebugVariables::releaseMemory() {
690 static_cast<LDVImpl*>(pImpl)->clear();
693 LiveDebugVariables::~LiveDebugVariables() {
695 delete static_cast<LDVImpl*>(pImpl);
699 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
700 const TargetRegisterInfo *TRI) {
701 for (unsigned i = locations.size(); i; --i) {
702 unsigned LocNo = i - 1;
703 MachineOperand &Loc = locations[LocNo];
704 if (!Loc.isReg() || Loc.getReg() != OldReg)
706 if (TargetRegisterInfo::isPhysicalRegister(NewReg))
707 Loc.substPhysReg(NewReg, *TRI);
709 Loc.substVirtReg(NewReg, SubIdx, *TRI);
710 coalesceLocation(LocNo);
715 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) {
716 UserValue *UV = lookupVirtReg(OldReg);
720 if (TargetRegisterInfo::isVirtualRegister(NewReg))
721 mapVirtReg(NewReg, UV);
722 virtRegToEqClass.erase(OldReg);
725 UV->renameRegister(OldReg, NewReg, SubIdx, TRI);
730 void LiveDebugVariables::
731 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) {
733 static_cast<LDVImpl*>(pImpl)->renameRegister(OldReg, NewReg, SubIdx);
736 //===----------------------------------------------------------------------===//
737 // Live Range Splitting
738 //===----------------------------------------------------------------------===//
741 UserValue::splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs) {
743 dbgs() << "Splitting Loc" << OldLocNo << '\t';
746 bool DidChange = false;
747 LocMap::iterator LocMapI;
748 LocMapI.setMap(locInts);
749 for (unsigned i = 0; i != NewRegs.size(); ++i) {
750 LiveInterval *LI = NewRegs[i];
754 // Don't allocate the new LocNo until it is needed.
755 unsigned NewLocNo = ~0u;
757 // Iterate over the overlaps between locInts and LI.
758 LocMapI.find(LI->beginIndex());
759 if (!LocMapI.valid())
761 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
762 LiveInterval::iterator LIE = LI->end();
763 while (LocMapI.valid() && LII != LIE) {
764 // At this point, we know that LocMapI.stop() > LII->start.
765 LII = LI->advanceTo(LII, LocMapI.start());
769 // Now LII->end > LocMapI.start(). Do we have an overlap?
770 if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
771 // Overlapping correct location. Allocate NewLocNo now.
772 if (NewLocNo == ~0u) {
773 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
774 MO.setSubReg(locations[OldLocNo].getSubReg());
775 NewLocNo = getLocationNo(MO);
779 SlotIndex LStart = LocMapI.start();
780 SlotIndex LStop = LocMapI.stop();
782 // Trim LocMapI down to the LII overlap.
783 if (LStart < LII->start)
784 LocMapI.setStartUnchecked(LII->start);
785 if (LStop > LII->end)
786 LocMapI.setStopUnchecked(LII->end);
788 // Change the value in the overlap. This may trigger coalescing.
789 LocMapI.setValue(NewLocNo);
791 // Re-insert any removed OldLocNo ranges.
792 if (LStart < LocMapI.start()) {
793 LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
795 assert(LocMapI.valid() && "Unexpected coalescing");
797 if (LStop > LocMapI.stop()) {
799 LocMapI.insert(LII->end, LStop, OldLocNo);
804 // Advance to the next overlap.
805 if (LII->end < LocMapI.stop()) {
808 LocMapI.advanceTo(LII->start);
811 if (!LocMapI.valid())
813 LII = LI->advanceTo(LII, LocMapI.start());
818 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
819 locations.erase(locations.begin() + OldLocNo);
821 while (LocMapI.valid()) {
822 unsigned v = LocMapI.value();
824 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
825 << LocMapI.stop() << ")\n");
829 LocMapI.setValueUnchecked(v-1);
834 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), 0);});
839 UserValue::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
840 bool DidChange = false;
841 // Split locations referring to OldReg. Iterate backwards so splitLocation can
842 // safely erase unuused locations.
843 for (unsigned i = locations.size(); i ; --i) {
844 unsigned LocNo = i-1;
845 const MachineOperand *Loc = &locations[LocNo];
846 if (!Loc->isReg() || Loc->getReg() != OldReg)
848 DidChange |= splitLocation(LocNo, NewRegs);
853 void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
854 bool DidChange = false;
855 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
856 DidChange |= UV->splitRegister(OldReg, NewRegs);
861 // Map all of the new virtual registers.
862 UserValue *UV = lookupVirtReg(OldReg);
863 for (unsigned i = 0; i != NewRegs.size(); ++i)
864 mapVirtReg(NewRegs[i]->reg, UV);
867 void LiveDebugVariables::
868 splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
870 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
874 UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
875 // Iterate over locations in reverse makes it easier to handle coalescing.
876 for (unsigned i = locations.size(); i ; --i) {
877 unsigned LocNo = i-1;
878 MachineOperand &Loc = locations[LocNo];
879 // Only virtual registers are rewritten.
880 if (!Loc.isReg() || !Loc.getReg() ||
881 !TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
883 unsigned VirtReg = Loc.getReg();
884 if (VRM.isAssignedReg(VirtReg) &&
885 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
886 // This can create a %noreg operand in rare cases when the sub-register
887 // index is no longer available. That means the user value is in a
888 // non-existent sub-register, and %noreg is exactly what we want.
889 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
890 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT &&
891 VRM.isSpillSlotUsed(VRM.getStackSlot(VirtReg))) {
892 // FIXME: Translate SubIdx to a stackslot offset.
893 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
898 coalesceLocation(LocNo);
902 /// findInsertLocation - Find an iterator for inserting a DBG_VALUE
904 static MachineBasicBlock::iterator
905 findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
906 LiveIntervals &LIS) {
907 SlotIndex Start = LIS.getMBBStartIdx(MBB);
908 Idx = Idx.getBaseIndex();
910 // Try to find an insert location by going backwards from Idx.
912 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
913 // We've reached the beginning of MBB.
915 MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
918 Idx = Idx.getPrevIndex();
921 // Don't insert anything after the first terminator, though.
922 return MI->getDesc().isTerminator() ? MBB->getFirstTerminator() :
923 llvm::next(MachineBasicBlock::iterator(MI));
926 DebugLoc UserValue::findDebugLoc() {
931 void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
934 const TargetInstrInfo &TII) {
935 MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
936 MachineOperand &Loc = locations[LocNo];
937 ++NumInsertedDebugValues;
939 // Frame index locations may require a target callback.
941 MachineInstr *MI = TII.emitFrameIndexDebugValue(*MBB->getParent(),
942 Loc.getIndex(), offset, variable,
949 // This is not a frame index, or the target is happy with a standard FI.
950 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
951 .addOperand(Loc).addImm(offset).addMetadata(variable);
954 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
955 const TargetInstrInfo &TII) {
956 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
958 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
959 SlotIndex Start = I.start();
960 SlotIndex Stop = I.stop();
961 unsigned LocNo = I.value();
962 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
963 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
964 SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
966 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
967 insertDebugValue(MBB, Start, LocNo, LIS, TII);
968 // This interval may span multiple basic blocks.
969 // Insert a DBG_VALUE into each one.
970 while(Stop > MBBEnd) {
971 // Move to the next block.
975 MBBEnd = LIS.getMBBEndIdx(MBB);
976 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
977 insertDebugValue(MBB, Start, LocNo, LIS, TII);
979 DEBUG(dbgs() << '\n');
987 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
988 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
989 const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
990 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
991 DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
992 userValues[i]->rewriteLocations(*VRM, *TRI);
993 userValues[i]->emitDebugValues(VRM, *LIS, *TII);
997 void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
999 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
1004 void LiveDebugVariables::dump() {
1006 static_cast<LDVImpl*>(pImpl)->print(dbgs());