the various ConstantExpr::get*Ty methods existed to work with issues around
[llvm/stm8.git] / lib / CodeGen / LiveDebugVariables.cpp
blob5d38c83b49c27a972d5b92ace6d70b2131987663
1 //===- LiveDebugVariables.cpp - Tracking debug info variables -------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
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"
41 using namespace llvm;
43 static cl::opt<bool>
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>();
59 AU.setPreservesAll();
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.
71 ///
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.
74 ///
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.
79 namespace {
80 class LDVImpl;
81 class UserValue {
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.
93 LocMap locInts;
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);
108 public:
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)
119 l = l->leader;
120 return leader = l;
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();
134 if (!L1)
135 return L2;
136 L1 = L1->getLeader();
137 if (L1 == L2)
138 return L1;
139 // Splice L2 before L1's members.
140 UserValue *End = L2;
141 while (End->next)
142 End->leader = L1, End = End->next;
143 End->leader = L1;
144 End->next = L1->next;
145 L1->next = L2;
146 return L1;
149 /// getLocationNo - Return the location number that matches Loc.
150 unsigned getLocationNo(const MachineOperand &LocMO) {
151 if (LocMO.isReg()) {
152 if (LocMO.getReg() == 0)
153 return ~0u;
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())
159 return i;
160 } else
161 for (unsigned i = 0, e = locations.size(); i != e; ++i)
162 if (LocMO.isIdenticalTo(locations[i]))
163 return 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));
184 /// extendDef - Extend the current definition as far as possible down the
185 /// dominator tree. Stop when meeting an existing def or when leaving the live
186 /// range of VNI.
187 /// End points where VNI is no longer live are added to Kills.
188 /// @param Idx Starting point for the definition.
189 /// @param LocNo Location number to propagate.
190 /// @param LI Restrict liveness to where LI has the value VNI. May be null.
191 /// @param VNI When LI is not null, this is the value to restrict to.
192 /// @param Kills Append end points of VNI's live range to Kills.
193 /// @param LIS Live intervals analysis.
194 /// @param MDT Dominator tree.
195 void extendDef(SlotIndex Idx, unsigned LocNo,
196 LiveInterval *LI, const VNInfo *VNI,
197 SmallVectorImpl<SlotIndex> *Kills,
198 LiveIntervals &LIS, MachineDominatorTree &MDT);
200 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
201 /// registers. Determine if any of the copies are available at the kill
202 /// points, and add defs if possible.
203 /// @param LI Scan for copies of the value in LI->reg.
204 /// @param LocNo Location number of LI->reg.
205 /// @param Kills Points where the range of LocNo could be extended.
206 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
207 void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
208 const SmallVectorImpl<SlotIndex> &Kills,
209 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
210 MachineRegisterInfo &MRI,
211 LiveIntervals &LIS);
213 /// computeIntervals - Compute the live intervals of all locations after
214 /// collecting all their def points.
215 void computeIntervals(MachineRegisterInfo &MRI,
216 LiveIntervals &LIS, MachineDominatorTree &MDT);
218 /// renameRegister - Update locations to rewrite OldReg as NewReg:SubIdx.
219 void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
220 const TargetRegisterInfo *TRI);
222 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
223 /// live. Returns true if any changes were made.
224 bool splitRegister(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
226 /// rewriteLocations - Rewrite virtual register locations according to the
227 /// provided virtual register map.
228 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
230 /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
231 void emitDebugValues(VirtRegMap *VRM,
232 LiveIntervals &LIS, const TargetInstrInfo &TRI);
234 /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
235 /// variable may have more than one corresponding DBG_VALUE instructions.
236 /// Only first one needs DebugLoc to identify variable's lexical scope
237 /// in source file.
238 DebugLoc findDebugLoc();
239 void print(raw_ostream&, const TargetMachine*);
241 } // namespace
243 /// LDVImpl - Implementation of the LiveDebugVariables pass.
244 namespace {
245 class LDVImpl {
246 LiveDebugVariables &pass;
247 LocMap::Allocator allocator;
248 MachineFunction *MF;
249 LiveIntervals *LIS;
250 MachineDominatorTree *MDT;
251 const TargetRegisterInfo *TRI;
253 /// userValues - All allocated UserValue instances.
254 SmallVector<UserValue*, 8> userValues;
256 /// Map virtual register to eq class leader.
257 typedef DenseMap<unsigned, UserValue*> VRMap;
258 VRMap virtRegToEqClass;
260 /// Map user variable to eq class leader.
261 typedef DenseMap<const MDNode *, UserValue*> UVMap;
262 UVMap userVarMap;
264 /// getUserValue - Find or create a UserValue.
265 UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL);
267 /// lookupVirtReg - Find the EC leader for VirtReg or null.
268 UserValue *lookupVirtReg(unsigned VirtReg);
270 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
271 /// @param MI DBG_VALUE instruction
272 /// @param Idx Last valid SLotIndex before instruction.
273 /// @return True if the DBG_VALUE instruction should be deleted.
274 bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
276 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
277 /// a UserValue def for each instruction.
278 /// @param mf MachineFunction to be scanned.
279 /// @return True if any debug values were found.
280 bool collectDebugValues(MachineFunction &mf);
282 /// computeIntervals - Compute the live intervals of all user values after
283 /// collecting all their def points.
284 void computeIntervals();
286 public:
287 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
288 bool runOnMachineFunction(MachineFunction &mf);
290 /// clear - Relase all memory.
291 void clear() {
292 DeleteContainerPointers(userValues);
293 userValues.clear();
294 virtRegToEqClass.clear();
295 userVarMap.clear();
298 /// mapVirtReg - Map virtual register to an equivalence class.
299 void mapVirtReg(unsigned VirtReg, UserValue *EC);
301 /// renameRegister - Replace all references to OldReg with NewReg:SubIdx.
302 void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
304 /// splitRegister - Replace all references to OldReg with NewRegs.
305 void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs);
307 /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
308 void emitDebugValues(VirtRegMap *VRM);
310 void print(raw_ostream&);
312 } // namespace
314 void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
315 if (const MDString *MDS = dyn_cast<MDString>(variable->getOperand(2)))
316 OS << "!\"" << MDS->getString() << "\"\t";
317 if (offset)
318 OS << '+' << offset;
319 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
320 OS << " [" << I.start() << ';' << I.stop() << "):";
321 if (I.value() == ~0u)
322 OS << "undef";
323 else
324 OS << I.value();
326 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
327 OS << " Loc" << i << '=';
328 locations[i].print(OS, TM);
330 OS << '\n';
333 void LDVImpl::print(raw_ostream &OS) {
334 OS << "********** DEBUG VARIABLES **********\n";
335 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
336 userValues[i]->print(OS, &MF->getTarget());
339 void UserValue::coalesceLocation(unsigned LocNo) {
340 unsigned KeepLoc = 0;
341 for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
342 if (KeepLoc == LocNo)
343 continue;
344 if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
345 break;
347 // No matches.
348 if (KeepLoc == locations.size())
349 return;
351 // Keep the smaller location, erase the larger one.
352 unsigned EraseLoc = LocNo;
353 if (KeepLoc > EraseLoc)
354 std::swap(KeepLoc, EraseLoc);
355 locations.erase(locations.begin() + EraseLoc);
357 // Rewrite values.
358 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
359 unsigned v = I.value();
360 if (v == EraseLoc)
361 I.setValue(KeepLoc); // Coalesce when possible.
362 else if (v > EraseLoc)
363 I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
367 void UserValue::mapVirtRegs(LDVImpl *LDV) {
368 for (unsigned i = 0, e = locations.size(); i != e; ++i)
369 if (locations[i].isReg() &&
370 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
371 LDV->mapVirtReg(locations[i].getReg(), this);
374 UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
375 DebugLoc DL) {
376 UserValue *&Leader = userVarMap[Var];
377 if (Leader) {
378 UserValue *UV = Leader->getLeader();
379 Leader = UV;
380 for (; UV; UV = UV->getNext())
381 if (UV->match(Var, Offset))
382 return UV;
385 UserValue *UV = new UserValue(Var, Offset, DL, allocator);
386 userValues.push_back(UV);
387 Leader = UserValue::merge(Leader, UV);
388 return UV;
391 void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
392 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
393 UserValue *&Leader = virtRegToEqClass[VirtReg];
394 Leader = UserValue::merge(Leader, EC);
397 UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
398 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
399 return UV->getLeader();
400 return 0;
403 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
404 // DBG_VALUE loc, offset, variable
405 if (MI->getNumOperands() != 3 ||
406 !MI->getOperand(1).isImm() || !MI->getOperand(2).isMetadata()) {
407 DEBUG(dbgs() << "Can't handle " << *MI);
408 return false;
411 // Get or create the UserValue for (variable,offset).
412 unsigned Offset = MI->getOperand(1).getImm();
413 const MDNode *Var = MI->getOperand(2).getMetadata();
414 UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc());
415 UV->addDef(Idx, MI->getOperand(0));
416 return true;
419 bool LDVImpl::collectDebugValues(MachineFunction &mf) {
420 bool Changed = false;
421 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
422 ++MFI) {
423 MachineBasicBlock *MBB = MFI;
424 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
425 MBBI != MBBE;) {
426 if (!MBBI->isDebugValue()) {
427 ++MBBI;
428 continue;
430 // DBG_VALUE has no slot index, use the previous instruction instead.
431 SlotIndex Idx = MBBI == MBB->begin() ?
432 LIS->getMBBStartIdx(MBB) :
433 LIS->getInstructionIndex(llvm::prior(MBBI)).getDefIndex();
434 // Handle consecutive DBG_VALUE instructions with the same slot index.
435 do {
436 if (handleDebugValue(MBBI, Idx)) {
437 MBBI = MBB->erase(MBBI);
438 Changed = true;
439 } else
440 ++MBBI;
441 } while (MBBI != MBBE && MBBI->isDebugValue());
444 return Changed;
447 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
448 LiveInterval *LI, const VNInfo *VNI,
449 SmallVectorImpl<SlotIndex> *Kills,
450 LiveIntervals &LIS, MachineDominatorTree &MDT) {
451 SmallVector<SlotIndex, 16> Todo;
452 Todo.push_back(Idx);
454 do {
455 SlotIndex Start = Todo.pop_back_val();
456 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
457 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
458 LocMap::iterator I = locInts.find(Start);
460 // Limit to VNI's live range.
461 bool ToEnd = true;
462 if (LI && VNI) {
463 LiveRange *Range = LI->getLiveRangeContaining(Start);
464 if (!Range || Range->valno != VNI) {
465 if (Kills)
466 Kills->push_back(Start);
467 continue;
469 if (Range->end < Stop)
470 Stop = Range->end, ToEnd = false;
473 // There could already be a short def at Start.
474 if (I.valid() && I.start() <= Start) {
475 // Stop when meeting a different location or an already extended interval.
476 Start = Start.getNextSlot();
477 if (I.value() != LocNo || I.stop() != Start)
478 continue;
479 // This is a one-slot placeholder. Just skip it.
480 ++I;
483 // Limited by the next def.
484 if (I.valid() && I.start() < Stop)
485 Stop = I.start(), ToEnd = false;
486 // Limited by VNI's live range.
487 else if (!ToEnd && Kills)
488 Kills->push_back(Stop);
490 if (Start >= Stop)
491 continue;
493 I.insert(Start, Stop, LocNo);
495 // If we extended to the MBB end, propagate down the dominator tree.
496 if (!ToEnd)
497 continue;
498 const std::vector<MachineDomTreeNode*> &Children =
499 MDT.getNode(MBB)->getChildren();
500 for (unsigned i = 0, e = Children.size(); i != e; ++i)
501 Todo.push_back(LIS.getMBBStartIdx(Children[i]->getBlock()));
502 } while (!Todo.empty());
505 void
506 UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
507 const SmallVectorImpl<SlotIndex> &Kills,
508 SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
509 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
510 if (Kills.empty())
511 return;
512 // Don't track copies from physregs, there are too many uses.
513 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
514 return;
516 // Collect all the (vreg, valno) pairs that are copies of LI.
517 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
518 for (MachineRegisterInfo::use_nodbg_iterator
519 UI = MRI.use_nodbg_begin(LI->reg),
520 UE = MRI.use_nodbg_end(); UI != UE; ++UI) {
521 // Copies of the full value.
522 if (UI.getOperand().getSubReg() || !UI->isCopy())
523 continue;
524 MachineInstr *MI = &*UI;
525 unsigned DstReg = MI->getOperand(0).getReg();
527 // Don't follow copies to physregs. These are usually setting up call
528 // arguments, and the argument registers are always call clobbered. We are
529 // better off in the source register which could be a callee-saved register,
530 // or it could be spilled.
531 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
532 continue;
534 // Is LocNo extended to reach this copy? If not, another def may be blocking
535 // it, or we are looking at a wrong value of LI.
536 SlotIndex Idx = LIS.getInstructionIndex(MI);
537 LocMap::iterator I = locInts.find(Idx.getUseIndex());
538 if (!I.valid() || I.value() != LocNo)
539 continue;
541 if (!LIS.hasInterval(DstReg))
542 continue;
543 LiveInterval *DstLI = &LIS.getInterval(DstReg);
544 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getDefIndex());
545 assert(DstVNI && DstVNI->def == Idx.getDefIndex() && "Bad copy value");
546 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
549 if (CopyValues.empty())
550 return;
552 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
554 // Try to add defs of the copied values for each kill point.
555 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
556 SlotIndex Idx = Kills[i];
557 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
558 LiveInterval *DstLI = CopyValues[j].first;
559 const VNInfo *DstVNI = CopyValues[j].second;
560 if (DstLI->getVNInfoAt(Idx) != DstVNI)
561 continue;
562 // Check that there isn't already a def at Idx
563 LocMap::iterator I = locInts.find(Idx);
564 if (I.valid() && I.start() <= Idx)
565 continue;
566 DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
567 << DstVNI->id << " in " << *DstLI << '\n');
568 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
569 assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
570 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
571 I.insert(Idx, Idx.getNextSlot(), LocNo);
572 NewDefs.push_back(std::make_pair(Idx, LocNo));
573 break;
578 void
579 UserValue::computeIntervals(MachineRegisterInfo &MRI,
580 LiveIntervals &LIS,
581 MachineDominatorTree &MDT) {
582 SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
584 // Collect all defs to be extended (Skipping undefs).
585 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
586 if (I.value() != ~0u)
587 Defs.push_back(std::make_pair(I.start(), I.value()));
589 // Extend all defs, and possibly add new ones along the way.
590 for (unsigned i = 0; i != Defs.size(); ++i) {
591 SlotIndex Idx = Defs[i].first;
592 unsigned LocNo = Defs[i].second;
593 const MachineOperand &Loc = locations[LocNo];
595 // Register locations are constrained to where the register value is live.
596 if (Loc.isReg() && LIS.hasInterval(Loc.getReg())) {
597 LiveInterval *LI = &LIS.getInterval(Loc.getReg());
598 const VNInfo *VNI = LI->getVNInfoAt(Idx);
599 SmallVector<SlotIndex, 16> Kills;
600 extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT);
601 addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
602 } else
603 extendDef(Idx, LocNo, 0, 0, 0, LIS, MDT);
606 // Finally, erase all the undefs.
607 for (LocMap::iterator I = locInts.begin(); I.valid();)
608 if (I.value() == ~0u)
609 I.erase();
610 else
611 ++I;
614 void LDVImpl::computeIntervals() {
615 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
616 userValues[i]->computeIntervals(MF->getRegInfo(), *LIS, *MDT);
617 userValues[i]->mapVirtRegs(this);
621 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
622 MF = &mf;
623 LIS = &pass.getAnalysis<LiveIntervals>();
624 MDT = &pass.getAnalysis<MachineDominatorTree>();
625 TRI = mf.getTarget().getRegisterInfo();
626 clear();
627 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
628 << ((Value*)mf.getFunction())->getName()
629 << " **********\n");
631 bool Changed = collectDebugValues(mf);
632 computeIntervals();
633 DEBUG(print(dbgs()));
634 return Changed;
637 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
638 if (!EnableLDV)
639 return false;
640 if (!pImpl)
641 pImpl = new LDVImpl(this);
642 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
645 void LiveDebugVariables::releaseMemory() {
646 if (pImpl)
647 static_cast<LDVImpl*>(pImpl)->clear();
650 LiveDebugVariables::~LiveDebugVariables() {
651 if (pImpl)
652 delete static_cast<LDVImpl*>(pImpl);
655 void UserValue::
656 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
657 const TargetRegisterInfo *TRI) {
658 for (unsigned i = locations.size(); i; --i) {
659 unsigned LocNo = i - 1;
660 MachineOperand &Loc = locations[LocNo];
661 if (!Loc.isReg() || Loc.getReg() != OldReg)
662 continue;
663 if (TargetRegisterInfo::isPhysicalRegister(NewReg))
664 Loc.substPhysReg(NewReg, *TRI);
665 else
666 Loc.substVirtReg(NewReg, SubIdx, *TRI);
667 coalesceLocation(LocNo);
671 void LDVImpl::
672 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) {
673 UserValue *UV = lookupVirtReg(OldReg);
674 if (!UV)
675 return;
677 if (TargetRegisterInfo::isVirtualRegister(NewReg))
678 mapVirtReg(NewReg, UV);
679 virtRegToEqClass.erase(OldReg);
681 do {
682 UV->renameRegister(OldReg, NewReg, SubIdx, TRI);
683 UV = UV->getNext();
684 } while (UV);
687 void LiveDebugVariables::
688 renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) {
689 if (pImpl)
690 static_cast<LDVImpl*>(pImpl)->renameRegister(OldReg, NewReg, SubIdx);
693 //===----------------------------------------------------------------------===//
694 // Live Range Splitting
695 //===----------------------------------------------------------------------===//
697 bool
698 UserValue::splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs) {
699 DEBUG({
700 dbgs() << "Splitting Loc" << OldLocNo << '\t';
701 print(dbgs(), 0);
703 bool DidChange = false;
704 LocMap::iterator LocMapI;
705 LocMapI.setMap(locInts);
706 for (unsigned i = 0; i != NewRegs.size(); ++i) {
707 LiveInterval *LI = NewRegs[i];
708 if (LI->empty())
709 continue;
711 // Don't allocate the new LocNo until it is needed.
712 unsigned NewLocNo = ~0u;
714 // Iterate over the overlaps between locInts and LI.
715 LocMapI.find(LI->beginIndex());
716 if (!LocMapI.valid())
717 continue;
718 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
719 LiveInterval::iterator LIE = LI->end();
720 while (LocMapI.valid() && LII != LIE) {
721 // At this point, we know that LocMapI.stop() > LII->start.
722 LII = LI->advanceTo(LII, LocMapI.start());
723 if (LII == LIE)
724 break;
726 // Now LII->end > LocMapI.start(). Do we have an overlap?
727 if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
728 // Overlapping correct location. Allocate NewLocNo now.
729 if (NewLocNo == ~0u) {
730 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
731 MO.setSubReg(locations[OldLocNo].getSubReg());
732 NewLocNo = getLocationNo(MO);
733 DidChange = true;
736 SlotIndex LStart = LocMapI.start();
737 SlotIndex LStop = LocMapI.stop();
739 // Trim LocMapI down to the LII overlap.
740 if (LStart < LII->start)
741 LocMapI.setStartUnchecked(LII->start);
742 if (LStop > LII->end)
743 LocMapI.setStopUnchecked(LII->end);
745 // Change the value in the overlap. This may trigger coalescing.
746 LocMapI.setValue(NewLocNo);
748 // Re-insert any removed OldLocNo ranges.
749 if (LStart < LocMapI.start()) {
750 LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
751 ++LocMapI;
752 assert(LocMapI.valid() && "Unexpected coalescing");
754 if (LStop > LocMapI.stop()) {
755 ++LocMapI;
756 LocMapI.insert(LII->end, LStop, OldLocNo);
757 --LocMapI;
761 // Advance to the next overlap.
762 if (LII->end < LocMapI.stop()) {
763 if (++LII == LIE)
764 break;
765 LocMapI.advanceTo(LII->start);
766 } else {
767 ++LocMapI;
768 if (!LocMapI.valid())
769 break;
770 LII = LI->advanceTo(LII, LocMapI.start());
775 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
776 locations.erase(locations.begin() + OldLocNo);
777 LocMapI.goToBegin();
778 while (LocMapI.valid()) {
779 unsigned v = LocMapI.value();
780 if (v == OldLocNo) {
781 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
782 << LocMapI.stop() << ")\n");
783 LocMapI.erase();
784 } else {
785 if (v > OldLocNo)
786 LocMapI.setValueUnchecked(v-1);
787 ++LocMapI;
791 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), 0);});
792 return DidChange;
795 bool
796 UserValue::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
797 bool DidChange = false;
798 // Split locations referring to OldReg. Iterate backwards so splitLocation can
799 // safely erase unuused locations.
800 for (unsigned i = locations.size(); i ; --i) {
801 unsigned LocNo = i-1;
802 const MachineOperand *Loc = &locations[LocNo];
803 if (!Loc->isReg() || Loc->getReg() != OldReg)
804 continue;
805 DidChange |= splitLocation(LocNo, NewRegs);
807 return DidChange;
810 void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
811 bool DidChange = false;
812 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
813 DidChange |= UV->splitRegister(OldReg, NewRegs);
815 if (!DidChange)
816 return;
818 // Map all of the new virtual registers.
819 UserValue *UV = lookupVirtReg(OldReg);
820 for (unsigned i = 0; i != NewRegs.size(); ++i)
821 mapVirtReg(NewRegs[i]->reg, UV);
824 void LiveDebugVariables::
825 splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
826 if (pImpl)
827 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
830 void
831 UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
832 // Iterate over locations in reverse makes it easier to handle coalescing.
833 for (unsigned i = locations.size(); i ; --i) {
834 unsigned LocNo = i-1;
835 MachineOperand &Loc = locations[LocNo];
836 // Only virtual registers are rewritten.
837 if (!Loc.isReg() || !Loc.getReg() ||
838 !TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
839 continue;
840 unsigned VirtReg = Loc.getReg();
841 if (VRM.isAssignedReg(VirtReg) &&
842 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
843 // This can create a %noreg operand in rare cases when the sub-register
844 // index is no longer available. That means the user value is in a
845 // non-existent sub-register, and %noreg is exactly what we want.
846 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
847 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT &&
848 VRM.isSpillSlotUsed(VRM.getStackSlot(VirtReg))) {
849 // FIXME: Translate SubIdx to a stackslot offset.
850 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
851 } else {
852 Loc.setReg(0);
853 Loc.setSubReg(0);
855 coalesceLocation(LocNo);
859 /// findInsertLocation - Find an iterator for inserting a DBG_VALUE
860 /// instruction.
861 static MachineBasicBlock::iterator
862 findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
863 LiveIntervals &LIS) {
864 SlotIndex Start = LIS.getMBBStartIdx(MBB);
865 Idx = Idx.getBaseIndex();
867 // Try to find an insert location by going backwards from Idx.
868 MachineInstr *MI;
869 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
870 // We've reached the beginning of MBB.
871 if (Idx == Start) {
872 MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
873 return I;
875 Idx = Idx.getPrevIndex();
878 // Don't insert anything after the first terminator, though.
879 return MI->getDesc().isTerminator() ? MBB->getFirstTerminator() :
880 llvm::next(MachineBasicBlock::iterator(MI));
883 DebugLoc UserValue::findDebugLoc() {
884 DebugLoc D = dl;
885 dl = DebugLoc();
886 return D;
888 void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
889 unsigned LocNo,
890 LiveIntervals &LIS,
891 const TargetInstrInfo &TII) {
892 MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
893 MachineOperand &Loc = locations[LocNo];
895 // Frame index locations may require a target callback.
896 if (Loc.isFI()) {
897 MachineInstr *MI = TII.emitFrameIndexDebugValue(*MBB->getParent(),
898 Loc.getIndex(), offset, variable,
899 findDebugLoc());
900 if (MI) {
901 MBB->insert(I, MI);
902 return;
905 // This is not a frame index, or the target is happy with a standard FI.
906 BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
907 .addOperand(Loc).addImm(offset).addMetadata(variable);
910 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
911 const TargetInstrInfo &TII) {
912 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
914 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
915 SlotIndex Start = I.start();
916 SlotIndex Stop = I.stop();
917 unsigned LocNo = I.value();
918 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
919 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
920 SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
922 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
923 insertDebugValue(MBB, Start, LocNo, LIS, TII);
925 // This interval may span multiple basic blocks.
926 // Insert a DBG_VALUE into each one.
927 while(Stop > MBBEnd) {
928 // Move to the next block.
929 Start = MBBEnd;
930 if (++MBB == MFEnd)
931 break;
932 MBBEnd = LIS.getMBBEndIdx(MBB);
933 DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
934 insertDebugValue(MBB, Start, LocNo, LIS, TII);
936 DEBUG(dbgs() << '\n');
937 if (MBB == MFEnd)
938 break;
940 ++I;
944 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
945 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
946 const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
947 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
948 DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
949 userValues[i]->rewriteLocations(*VRM, *TRI);
950 userValues[i]->emitDebugValues(VRM, *LIS, *TII);
954 void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
955 if (pImpl)
956 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
960 #ifndef NDEBUG
961 void LiveDebugVariables::dump() {
962 if (pImpl)
963 static_cast<LDVImpl*>(pImpl)->print(dbgs());
965 #endif