Index: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp =================================================================== --- llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp +++ llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp @@ -148,6 +148,7 @@ #include "llvm/ADT/DenseMap.h" #include "llvm/ADT/PostOrderIterator.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/SmallSet.h" #include "llvm/ADT/SmallVector.h" @@ -184,6 +185,7 @@ #include "llvm/Support/Debug.h" #include "llvm/Support/TypeSize.h" #include "llvm/Support/raw_ostream.h" +#include "llvm/Transforms/Utils/SSAUpdaterImpl.h" #include #include #include @@ -199,6 +201,8 @@ using namespace llvm; +// SSAUpdaterImple sets DEBUG_TYPE, change it. +#undef DEBUG_TYPE #define DEBUG_TYPE "livedebugvalues" // Act more like the VarLoc implementation, by propagating some locations too @@ -1329,6 +1333,7 @@ const TargetRegisterInfo *TRI; const TargetInstrInfo *TII; const TargetFrameLowering *TFI; + const MachineFrameInfo *MFI; BitVector CalleeSavedRegs; LexicalScopes LS; TargetPassConfig *TPC; @@ -1369,6 +1374,23 @@ /// instruction numbers in DBG_INSTR_REFs into machine value numbers. std::map DebugInstrNumToInstr; + /// Record of where we observed a DBG_PHI instruction. + class DebugPHIRecord { + public: + uint64_t InstrNum; ///< Instruction number of this DBG_PHI. + MachineBasicBlock *MBB; ///< Block where DBG_PHI occurred. + ValueIDNum ValueRead; ///< The value number read by the DBG_PHI. + LocIdx ReadLoc; ///< Register/Stack location the DBG_PHI reads. + + operator unsigned() const { return InstrNum; } + }; + + /// Map from instruction numbers defined by DBG_PHIs to a record of what that + /// DBG_PHI read and where. Populated and edited during the machine value + /// location problem -- we use LLVMs SSA Updater to fix changes by + /// optimizations that destroy PHI instructions. + SmallVector DebugPHINumToValue; + // Map of overlapping variable fragments. OverlapMap OverlapFragments; VarToFragments SeenFragments; @@ -1395,7 +1417,8 @@ SpillLoc extractSpillBaseRegAndOffset(const MachineInstr &MI); /// Observe a single instruction while stepping through a block. - void process(MachineInstr &MI); + void process(MachineInstr &MI, ValueIDNum **MLiveOuts = nullptr, + ValueIDNum **MLiveIns = nullptr); /// Examines whether \p MI is a DBG_VALUE and notifies trackers. /// \returns true if MI was recognized and processed. @@ -1403,7 +1426,13 @@ /// Examines whether \p MI is a DBG_INSTR_REF and notifies trackers. /// \returns true if MI was recognized and processed. - bool transferDebugInstrRef(MachineInstr &MI); + bool transferDebugInstrRef(MachineInstr &MI, ValueIDNum **MLiveOuts, + ValueIDNum **MLiveIns); + + /// Stores value-information about where this PHI occurred, and what + /// instruction number is associated with it. + /// \returns true if MI was recognized and processed. + bool transferDebugPHI(MachineInstr &MI); /// Examines whether \p MI is copy instruction, and notifies trackers. /// \returns true if MI was recognized and processed. @@ -1422,6 +1451,18 @@ void accumulateFragmentMap(MachineInstr &MI); + /// Determine the machine value number referred to by (potentially several) + /// DBG_PHI instructions. Block duplication and tail folding can duplicate + /// DBG_PHIs, shifting the position where values in registers merge, and + /// forming another mini-ssa problem to solve. + /// \p Here the position of a DBG_INSTR_REF seeking a machine value number + /// \p InstrNum Debug instruction number defined by DBG_PHI instructions. + /// \returns The machine value number at position Here, or None. + Optional resolveDbgPHIs(MachineFunction &MF, + ValueIDNum **MLiveOuts, + ValueIDNum **MLiveIns, MachineInstr &Here, + uint64_t InstrNum); + /// Step through the function, recording register definitions and movements /// in an MLocTracker. Convert the observations into a per-block transfer /// function in \p MLocTransfer, suitable for using with the machine value @@ -1524,7 +1565,7 @@ /// right now "order of appearence in function, when explored in RPO", so /// that we can compare explictly against VarLocBasedImpl. void emitLocations(MachineFunction &MF, LiveInsT SavedLiveIns, - ValueIDNum **MInLocs, + ValueIDNum **MOutLocs, ValueIDNum **MInLocs, DenseMap &AllVarsNumbering); /// Boilerplate computation of some initial sets, artifical blocks and @@ -1637,7 +1678,9 @@ return true; } -bool InstrRefBasedLDV::transferDebugInstrRef(MachineInstr &MI) { +bool InstrRefBasedLDV::transferDebugInstrRef(MachineInstr &MI, + ValueIDNum **MLiveOuts, + ValueIDNum **MLiveIns) { if (!MI.isDebugRef()) return false; @@ -1679,8 +1722,10 @@ Optional NewID = None; // Try to lookup the instruction number, and find the machine value number - // that it defines. + // that it defines. It could be an instruction, or a PHI. auto InstrIt = DebugInstrNumToInstr.find(InstNo); + auto PHIIt = std::lower_bound(DebugPHINumToValue.begin(), + DebugPHINumToValue.end(), InstNo); if (InstrIt != DebugInstrNumToInstr.end()) { const MachineInstr &TargetInstr = *InstrIt->second.first; uint64_t BlockNo = TargetInstr.getParent()->getNumber(); @@ -1695,6 +1740,11 @@ unsigned LocID = MTracker->getLocID(MO.getReg(), false); LocIdx L = MTracker->LocIDToLocIdx[LocID]; NewID = ValueIDNum(BlockNo, InstrIt->second.second, L); + } else if (PHIIt != DebugPHINumToValue.end() && PHIIt->InstrNum == InstNo) { + // It's actually a PHI value. Which value it is might not be obvious, use + // the resolver helper to find out. + NewID = resolveDbgPHIs(*MI.getParent()->getParent(), MLiveOuts, MLiveIns, + MI, InstNo); } // We, we have a value number or None. Tell the variable value tracker about @@ -1749,6 +1799,55 @@ MachineInstr *DbgMI = MTracker->emitLoc(FoundLoc, V, Properties); TTracker->PendingDbgValues.push_back(DbgMI); TTracker->flushDbgValues(MI.getIterator(), nullptr); + return true; +} + +bool InstrRefBasedLDV::transferDebugPHI(MachineInstr &MI) { + if (!MI.isDebugPHI()) + return false; + + // Analyse these only when solving the machine value location problem. + if (VTracker || TTracker) + return true; + + // First operand is the value location, either a stack slot or register. + // Second is the debug instruction number of the original PHI. + const MachineOperand &MO = MI.getOperand(0); + unsigned InstrNum = MI.getOperand(1).getImm(); + + if (MO.isReg()) { + // The value is whatever's currently in the register. Read and record it, + // to be analysed later. + Register Reg = MO.getReg(); + ValueIDNum Num = MTracker->readReg(Reg); + auto PHIRec = DebugPHIRecord( + {InstrNum, MI.getParent(), Num, MTracker->lookupOrTrackRegister(Reg)}); + DebugPHINumToValue.push_back(PHIRec); + } else { + // The value is whatever's in this stack slot. + assert(MO.isFI()); + unsigned FI = MO.getIndex(); + + // If the stack slot is dead, then this was optimized away. + // FIXME: stack slot colouring should account for slots that get merged. + if (MFI->isDeadObjectIndex(FI)) + return true; + + // Identify this spill slot. + Register Base; + StackOffset Offs = TFI->getFrameIndexReference(*MI.getMF(), FI, Base); + SpillLoc SL = {Base, Offs}; + Optional Num = MTracker->readSpill(SL); + + if (!Num) + // Nothing ever writes to this slot. Curious, but nothing we can do. + return true; + + // Record this DBG_PHI for later analysis. + auto DbgPHI = DebugPHIRecord( + {InstrNum, MI.getParent(), *Num, *MTracker->getSpillMLoc(SL)}); + DebugPHINumToValue.push_back(DbgPHI); + } return true; } @@ -2121,13 +2220,16 @@ AllSeenFragments.insert(ThisFragment); } -void InstrRefBasedLDV::process(MachineInstr &MI) { +void InstrRefBasedLDV::process(MachineInstr &MI, ValueIDNum **MLiveOuts, + ValueIDNum **MLiveIns) { // Try to interpret an MI as a debug or transfer instruction. Only if it's // none of these should we interpret it's register defs as new value // definitions. if (transferDebugValue(MI)) return; - if (transferDebugInstrRef(MI)) + if (transferDebugInstrRef(MI, MLiveOuts, MLiveIns)) + return; + if (transferDebugPHI(MI)) return; if (transferRegisterCopy(MI)) return; @@ -3123,8 +3225,8 @@ #endif void InstrRefBasedLDV::emitLocations( - MachineFunction &MF, LiveInsT SavedLiveIns, ValueIDNum **MInLocs, - DenseMap &AllVarsNumbering) { + MachineFunction &MF, LiveInsT SavedLiveIns, ValueIDNum **MOutLocs, + ValueIDNum **MInLocs, DenseMap &AllVarsNumbering) { TTracker = new TransferTracker(TII, MTracker, MF, *TRI, CalleeSavedRegs); unsigned NumLocs = MTracker->getNumLocs(); @@ -3141,7 +3243,7 @@ CurBB = bbnum; CurInst = 1; for (auto &MI : MBB) { - process(MI); + process(MI, MOutLocs, MInLocs); TTracker->checkInstForNewValues(CurInst, MI.getIterator()); ++CurInst; } @@ -3219,6 +3321,7 @@ TII = MF.getSubtarget().getInstrInfo(); TFI = MF.getSubtarget().getFrameLowering(); TFI->getCalleeSaves(MF, CalleeSavedRegs); + MFI = &MF.getFrameInfo(); LS.initialize(MF); MTracker = @@ -3261,6 +3364,21 @@ // dataflow problem. mlocDataflow(MInLocs, MOutLocs, MLocTransfer); + // Patch up debug phi numbers, turning unknown block-live-in values into + // either live-through machine values, or PHIs. + for (auto &DBG_PHI : DebugPHINumToValue) { + // Identify unresolved block-live-ins. + ValueIDNum &Num = DBG_PHI.ValueRead; + if (!Num.isPHI()) + continue; + + unsigned BlockNo = Num.getBlock(); + LocIdx LocNo = Num.getLoc(); + Num = MInLocs[BlockNo][LocNo.asU64()]; + } + // Later, we'll be looking up ranges of instruction numbers. + llvm::sort(DebugPHINumToValue); + // Walk back through each block / instruction, collecting DBG_VALUE // instructions and recording what machine value their operands refer to. for (auto &OrderPair : OrderToBB) { @@ -3271,7 +3389,7 @@ MTracker->loadFromArray(MInLocs[CurBB], CurBB); CurInst = 1; for (auto &MI : MBB) { - process(MI); + process(MI, MOutLocs, MInLocs); ++CurInst; } MTracker->reset(); @@ -3326,7 +3444,7 @@ // Using the computed value locations and variable values for each block, // create the DBG_VALUE instructions representing the extended variable // locations. - emitLocations(MF, SavedLiveIns, MInLocs, AllVarsNumbering); + emitLocations(MF, SavedLiveIns, MOutLocs, MInLocs, AllVarsNumbering); for (int Idx = 0; Idx < MaxNumBlocks; ++Idx) { delete[] MOutLocs[Idx]; @@ -3349,6 +3467,7 @@ BBToOrder.clear(); BBNumToRPO.clear(); DebugInstrNumToInstr.clear(); + DebugPHINumToValue.clear(); return Changed; } @@ -3356,3 +3475,377 @@ LDVImpl *llvm::makeInstrRefBasedLiveDebugValues() { return new InstrRefBasedLDV(); } + +namespace { +class LDVSSABlock; +class LDVSSAUpdater; + +/// Represents an SSA PHI node for the SSA updater class. Contains the block +/// this PHI is in, the value number it would have, and the expected incoming +/// values from parent blocks. +class LDVSSAPhi { +public: + SmallVector, 4> IncomingValues; + LDVSSABlock *ParentBlock; + uint64_t PHIValNum; + LDVSSAPhi(uint64_t PHIValNum, LDVSSABlock *ParentBlock) + : ParentBlock(ParentBlock), PHIValNum(PHIValNum) {} + + LDVSSABlock *getParent() { return ParentBlock; } +}; + +/// Thin wrapper around a block predecessor iterator. Only difference from a +/// normal block iterator is that it dereferences to an LDVSSABlock. +class LDVSSABlockIterator { +public: + MachineBasicBlock::pred_iterator PredIt; + LDVSSAUpdater &Updater; + + LDVSSABlockIterator(MachineBasicBlock::pred_iterator PredIt, + LDVSSAUpdater &Updater) + : PredIt(PredIt), Updater(Updater) {} + + bool operator!=(const LDVSSABlockIterator &OtherIt) const { + return OtherIt.PredIt != PredIt; + } + + LDVSSABlockIterator &operator++() { + ++PredIt; + return *this; + } + + LDVSSABlock *operator*(); +}; + +/// Thin wrapper around a block for SSA Updater interface. Necessary because +/// we need to track the PHI value(s) that we may have observed as necessary +/// in this block. +class LDVSSABlock { +public: + MachineBasicBlock &BB; + LDVSSAUpdater &Updater; + using PHIListT = SmallVector; + /// List of PHIs in this block. There should only ever be one. + PHIListT PHIList; + + LDVSSABlock(MachineBasicBlock &BB, LDVSSAUpdater &Updater) + : BB(BB), Updater(Updater) {} + + LDVSSABlockIterator succ_begin() { + return LDVSSABlockIterator(BB.succ_begin(), Updater); + } + + LDVSSABlockIterator succ_end() { + return LDVSSABlockIterator(BB.succ_end(), Updater); + } + + /// SSAUpdater has requested a PHI: create that within this block record. + LDVSSAPhi *newPHI(uint64_t Value) { + PHIList.emplace_back(Value, this); + return &PHIList.back(); + } + + /// SSAUpdater wishes to know what PHIs already exist in this block. + PHIListT &phis() { return PHIList; } +}; + +/// Utility class for the SSAUpdater interface: tracks blocks, PHIs and values +/// while SSAUpdater is exploring the CFG. It's passed as a handle / baton to +// SSAUpdaterTraits. +class LDVSSAUpdater { +public: + /// Map of value numbers to PHI records. + DenseMap PHIs; + /// Map of which blocks generate Undef values -- blocks that are not + /// dominated by any Def. + DenseMap UndefMap; + /// Map of machine blocks to our own records of them. + DenseMap BlockMap; + /// Machine location where any PHI must occur. + LocIdx Loc; + /// Table of live-in machine value numbers for blocks / locations. + ValueIDNum **MLiveIns; + + LDVSSAUpdater(LocIdx L, ValueIDNum **MLiveIns) : Loc(L), MLiveIns(MLiveIns) {} + + void reset() { + PHIs.clear(); + UndefMap.clear(); + BlockMap.clear(); + } + + ~LDVSSAUpdater() { reset(); } + + /// For a given MBB, create a wrapper block for it. Stores it in the + /// LDVSSAUpdater block map. + LDVSSABlock *getSSALDVBlock(MachineBasicBlock *BB) { + auto it = BlockMap.find(BB); + if (it == BlockMap.end()) { + BlockMap[BB] = new LDVSSABlock(*BB, *this); + it = BlockMap.find(BB); + } + return it->second; + } + + /// Find the live-in value number for the given block. Looks up the value at + /// the PHI location on entry. + uint64_t getValue(LDVSSABlock *LDVBB) { + return MLiveIns[LDVBB->BB.getNumber()][Loc.asU64()].asU64(); + } +}; + +LDVSSABlock *LDVSSABlockIterator::operator*() { + return Updater.getSSALDVBlock(*PredIt); +} + +} // namespace + +namespace llvm { + +raw_ostream &operator<<(raw_ostream &out, const LDVSSAPhi &PHI) { + out << "SSALDVPHI " << PHI.PHIValNum; + return out; +} + +/// Template specialization to give SSAUpdater access to CFG and value +/// information. SSAUpdater calls methods in these traits, passing in the +/// LDVSSAUpdater object, to learn about blocks and the values they define. +/// It also provides methods to create PHI nodes and track them. +template <> class SSAUpdaterTraits { +public: + using BlkT = LDVSSABlock; + using ValT = uint64_t; + using PhiT = LDVSSAPhi; + using BlkSucc_iterator = LDVSSABlockIterator; + + // Methods to access block successors -- dereferencing to our wrapper class. + static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return BB->succ_begin(); } + static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return BB->succ_end(); } + + /// Iterator for PHI operands. + class PHI_iterator { + private: + LDVSSAPhi *PHI; + unsigned Idx; + + public: + explicit PHI_iterator(LDVSSAPhi *P) // begin iterator + : PHI(P), Idx(0) {} + PHI_iterator(LDVSSAPhi *P, bool) // end iterator + : PHI(P), Idx(PHI->IncomingValues.size()) {} + + PHI_iterator &operator++() { + Idx++; + return *this; + } + bool operator==(const PHI_iterator &X) const { return Idx == X.Idx; } + bool operator!=(const PHI_iterator &X) const { return !operator==(X); } + + uint64_t getIncomingValue() { return PHI->IncomingValues[Idx].second; } + + LDVSSABlock *getIncomingBlock() { return PHI->IncomingValues[Idx].first; } + }; + + static inline PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); } + + static inline PHI_iterator PHI_end(PhiT *PHI) { + return PHI_iterator(PHI, true); + } + + /// FindPredecessorBlocks - Put the predecessors of BB into the Preds + /// vector. + static void FindPredecessorBlocks(LDVSSABlock *BB, + SmallVectorImpl *Preds) { + for (MachineBasicBlock::pred_iterator PI = BB->BB.pred_begin(), + E = BB->BB.pred_end(); + PI != E; ++PI) + Preds->push_back(BB->Updater.getSSALDVBlock(*PI)); + } + + /// GetUndefVal - Normally creates an IMPLICIT_DEF instruction with a new + /// register. For LiveDebugValues, represents a block identified as not having + /// any DBG_PHI predecessors. + static uint64_t GetUndefVal(LDVSSABlock *BB, LDVSSAUpdater *Updater) { + // Create a value number for this block -- it needs to be unique and in the + // "undef" collection, so that we know it's not real. Use a number + // representing a PHI into this block. + uint64_t Num = ValueIDNum(BB->BB.getNumber(), 0, Updater->Loc).asU64(); + Updater->UndefMap[&BB->BB] = Num; + return Num; + } + + /// CreateEmptyPHI - Create a (representation of a) PHI in the given block. + /// SSAUpdater will populate it with information about incoming values. The + /// value number of this PHI is whatever the machine value number problem + /// solution determined it to be. This includes non-phi values if SSAUpdater + /// tries to create a PHI where the incoming values are identical. + static uint64_t CreateEmptyPHI(LDVSSABlock *BB, unsigned NumPreds, + LDVSSAUpdater *Updater) { + uint64_t PHIValNum = Updater->getValue(BB); + LDVSSAPhi *PHI = BB->newPHI(PHIValNum); + Updater->PHIs[PHIValNum] = PHI; + return PHIValNum; + } + + /// AddPHIOperand - Add the specified value as an operand of the PHI for + /// the specified predecessor block. + static void AddPHIOperand(LDVSSAPhi *PHI, uint64_t Val, LDVSSABlock *Pred) { + PHI->IncomingValues.push_back(std::make_pair(Pred, Val)); + } + + /// ValueIsPHI - Check if the instruction that defines the specified value + /// is a PHI instruction. + static LDVSSAPhi *ValueIsPHI(uint64_t Val, LDVSSAUpdater *Updater) { + auto PHIIt = Updater->PHIs.find(Val); + if (PHIIt == Updater->PHIs.end()) + return nullptr; + return PHIIt->second; + } + + /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source + /// operands, i.e., it was just added. + static LDVSSAPhi *ValueIsNewPHI(uint64_t Val, LDVSSAUpdater *Updater) { + LDVSSAPhi *PHI = ValueIsPHI(Val, Updater); + if (PHI && PHI->IncomingValues.size() == 0) + return PHI; + return nullptr; + } + + /// GetPHIValue - For the specified PHI instruction, return the value + /// that it defines. + static uint64_t GetPHIValue(LDVSSAPhi *PHI) { return PHI->PHIValNum; } +}; + +} // end namespace llvm + +Optional InstrRefBasedLDV::resolveDbgPHIs(MachineFunction &MF, + ValueIDNum **MLiveOuts, + ValueIDNum **MLiveIns, + MachineInstr &Here, + uint64_t InstrNum) { + // Pick out records of DBG_PHI instructions that have been observed. If there + // are none, then we cannot compute a value number. + auto RangePair = std::equal_range(DebugPHINumToValue.begin(), + DebugPHINumToValue.end(), InstrNum); + auto LowerIt = RangePair.first; + auto UpperIt = RangePair.second; + + // No DBG_PHI means there can be no location. + if (LowerIt == UpperIt) + return None; + + // If there's only one DBG_PHI, then that is our value number. + if (std::distance(LowerIt, UpperIt) == 1) + return LowerIt->ValueRead; + + auto DBGPHIRange = make_range(LowerIt, UpperIt); + + // Pick out the location (physreg, slot) where any PHIs must occur. It's + // technically possible for us to merge values in different registers in each + // block, but highly unlikely that LLVM will generate such code after register + // allocation. + LocIdx Loc = LowerIt->ReadLoc; + + // We have several DBG_PHIs, and a use position (the Here inst). All each + // DBG_PHI does is identify a value at a program position. We can treat each + // DBG_PHI like it's a Def of a value, and the use position is a Use of a + // value, just like SSA. We use the bulk-standard LLVM SSA updater class to + // determine which Def is used at the Use, and any PHIs that happen along + // the way. + // Adapted LLVM SSA Updater: + LDVSSAUpdater Updater(Loc, MLiveIns); + // Map of which Def or PHI is the current value in each block. + DenseMap AvailableValues; + // Set of PHIs that we have created along the way. + SmallVector CreatedPHIs; + + // Each existing DBG_PHI is a Def'd value under this model. Record these Defs + // for the SSAUpdater. + for (const auto &DBG_PHI : DBGPHIRange) { + LDVSSABlock *Block = Updater.getSSALDVBlock(DBG_PHI.MBB); + const ValueIDNum &Num = DBG_PHI.ValueRead; + AvailableValues.insert(std::make_pair(Block, Num.asU64())); + } + + LDVSSABlock *HereBlock = Updater.getSSALDVBlock(Here.getParent()); + const auto &AvailIt = AvailableValues.find(HereBlock); + if (AvailIt != AvailableValues.end()) { + // Actually, we already know what the value is -- the Use is in the same + // block as the Def. + return ValueIDNum::fromU64(AvailIt->second); + } + + // Otherwise, we must use the SSA Updater. It will identify the value number + // that we are to use, and the PHIs that must happen along the way. + SSAUpdaterImpl Impl(&Updater, &AvailableValues, &CreatedPHIs); + uint64_t ResultInt = Impl.GetValue(Updater.getSSALDVBlock(Here.getParent())); + ValueIDNum Result = ValueIDNum::fromU64(ResultInt); + + // We have the number for a PHI, or possibly live-through value, to be used + // at this Use. There are a number of things we have to check about it though: + // * Does any PHI use an 'Undef' (like an IMPLICIT_DEF) value? If so, this + // Use was not completely dominated by DBG_PHIs and we should abort. + // * Are the Defs or PHIs clobbered in a block? SSAUpdater isn't aware that + // we've left SSA form. Validate that the inputs to each PHI are the + // expected values. + // * Is a PHI we've created actually a merging of values, or are all the + // predecessor values the same, leading to a non-PHI machine value number? + // (SSAUpdater doesn't know that either). Remap validated PHIs into the + // the ValidatedValues collection below to sort this out. + DenseMap ValidatedValues; + + // Define all the input DBG_PHI values in ValidatedValues. + for (const auto &DBG_PHI : DBGPHIRange) { + LDVSSABlock *Block = Updater.getSSALDVBlock(DBG_PHI.MBB); + const ValueIDNum &Num = DBG_PHI.ValueRead; + ValidatedValues.insert(std::make_pair(Block, Num)); + } + + // Sort PHIs to validate into RPO-order. + SmallVector SortedPHIs; + for (auto &PHI : CreatedPHIs) + SortedPHIs.push_back(PHI); + + std::sort( + SortedPHIs.begin(), SortedPHIs.end(), [&](LDVSSAPhi *A, LDVSSAPhi *B) { + return BBToOrder[&A->getParent()->BB] < BBToOrder[&B->getParent()->BB]; + }); + + for (auto &PHI : SortedPHIs) { + ValueIDNum ThisBlockValue = + MLiveIns[PHI->ParentBlock->BB.getNumber()][Loc.asU64()]; + + // Are all these things actually defined? + for (auto &PHIIt : PHI->IncomingValues) { + // Any undef input means DBG_PHIs didn't dominate the use point. + if (Updater.UndefMap.find(&PHIIt.first->BB) != Updater.UndefMap.end()) + return None; + + ValueIDNum ValueToCheck; + ValueIDNum *BlockLiveOuts = MLiveOuts[PHIIt.first->BB.getNumber()]; + + auto VVal = ValidatedValues.find(PHIIt.first); + if (VVal == ValidatedValues.end()) { + // We cross a loop, and this is a backedge. LLVMs tail duplication + // happens so late that DBG_PHI instructions should not be able to + // migrate into loops -- meaning we can only be live-through this + // loop. + ValueToCheck = ThisBlockValue; + } else { + // Does the block have as a live-out, in the location we're examining, + // the value that we expect? If not, it's been moved or clobbered. + ValueToCheck = VVal->second; + } + + if (BlockLiveOuts[Loc.asU64()] != ValueToCheck) + return None; + } + + // Record this value as validated. + ValidatedValues.insert({PHI->ParentBlock, ThisBlockValue}); + } + + // All the PHIs are valid: we can return what the SSAUpdater said our value + // number was. + return Result; +} Index: llvm/test/DebugInfo/MIR/InstrRef/dbg-phis-in-ldv.mir =================================================================== --- /dev/null +++ llvm/test/DebugInfo/MIR/InstrRef/dbg-phis-in-ldv.mir @@ -0,0 +1,162 @@ +# RUN: llc %s -o - -mtriple=x86_64-unknown-unknown \ +# RUN: -experimental-debug-variable-locations -run-pass=livedebugvalues\ +# RUN: | FileCheck %s +# +# Test that a DBG_INSTR_REF that refers to a DBG_PHI, will be translated into a +# DBG_VALUE of the value read at that DBG_PHI. Same original code as +# phi-coalescing.mir. +# +--- | + ; ModuleID = 'phi-coalescing.mir' + source_filename = "test.c" + target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" + target triple = "x86_64-unknown-linux-gnu" + + define dso_local i32 @foo(i64 %bar, i64 %baz) !dbg !7 { + entry: + call void @llvm.dbg.value(metadata i64 %bar, metadata !12, metadata !DIExpression()), !dbg !13 + call void @llvm.dbg.value(metadata i64 %baz, metadata !14, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %bar), !dbg !15 + %add = add nsw i64 %bar, 12, !dbg !16 + call void @llvm.dbg.value(metadata i64 %add, metadata !12, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %add), !dbg !17 + %call = call i64 @getlong(), !dbg !18 + %tobool = icmp ne i64 %call, 0, !dbg !18 + br i1 %tobool, label %if.then, label %if.end, !dbg !20 + + if.then: ; preds = %entry + %add1 = add nsw i64 %add, 1, !dbg !21 + call void @llvm.dbg.value(metadata i64 %add1, metadata !12, metadata !DIExpression()), !dbg !13 + br label %if.end, !dbg !22 + + if.end: ; preds = %if.then, %entry + %bar.addr.0 = phi i64 [ %add1, %if.then ], [ %add, %entry ], !dbg !13 + call void @llvm.dbg.value(metadata i64 %bar.addr.0, metadata !12, metadata !DIExpression()), !dbg !13 + %add2 = add nsw i64 %bar.addr.0, %baz, !dbg !23 + call void @llvm.dbg.value(metadata i64 %add2, metadata !12, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %add2), !dbg !24 + %conv = trunc i64 %add2 to i32, !dbg !25 + ret i32 %conv, !dbg !26 + } + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.declare(metadata, metadata, metadata) + + declare dso_local void @ext(i64) + + declare dso_local i64 @getlong() + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.value(metadata, metadata, metadata) + + !llvm.dbg.cu = !{!0} + !llvm.module.flags = !{!3, !4, !5} + !llvm.ident = !{!6} + + !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None) + !1 = !DIFile(filename: "test.c", directory: "/tmp/out.c") + !2 = !{} + !3 = !{i32 7, !"Dwarf Version", i32 4} + !4 = !{i32 2, !"Debug Info Version", i32 3} + !5 = !{i32 1, !"wchar_size", i32 4} + !6 = !{!""} + !7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !8, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2) + !8 = !DISubroutineType(types: !9) + !9 = !{!10, !11, !11} + !10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !11 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed) + !12 = !DILocalVariable(name: "bar", arg: 1, scope: !7, file: !1, line: 3, type: !11) + !13 = !DILocation(line: 0, scope: !7) + !14 = !DILocalVariable(name: "baz", arg: 2, scope: !7, file: !1, line: 3, type: !11) + !15 = !DILocation(line: 4, column: 3, scope: !7) + !16 = !DILocation(line: 5, column: 7, scope: !7) + !17 = !DILocation(line: 6, column: 3, scope: !7) + !18 = !DILocation(line: 8, column: 7, scope: !19) + !19 = distinct !DILexicalBlock(scope: !7, file: !1, line: 8, column: 7) + !20 = !DILocation(line: 8, column: 7, scope: !7) + !21 = !DILocation(line: 9, column: 9, scope: !19) + !22 = !DILocation(line: 9, column: 5, scope: !19) + !23 = !DILocation(line: 11, column: 7, scope: !7) + !24 = !DILocation(line: 12, column: 3, scope: !7) + !25 = !DILocation(line: 13, column: 10, scope: !7) + !26 = !DILocation(line: 13, column: 3, scope: !7) + +... +--- +name: foo +alignment: 16 +tracksRegLiveness: true +liveins: + - { reg: '$rdi' } + - { reg: '$rsi' } +frameInfo: + stackSize: 24 + offsetAdjustment: -24 + maxAlignment: 1 + adjustsStack: true + hasCalls: true + maxCallFrameSize: 0 + cvBytesOfCalleeSavedRegisters: 16 +fixedStack: + - { id: 0, type: spill-slot, offset: -24, size: 8, alignment: 8, callee-saved-register: '$rbx' } + - { id: 1, type: spill-slot, offset: -16, size: 8, alignment: 16, callee-saved-register: '$r14' } +machineFunctionInfo: {} +body: | + bb.0.entry: + liveins: $rdi, $rsi, $r14, $rbx + + frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 16 + frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 24 + frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 32 + CFI_INSTRUCTION offset $rbx, -24 + CFI_INSTRUCTION offset $r14, -16 + $r14 = MOV64rr $rsi + $rbx = MOV64rr $rdi + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !15 + renamable $rbx = ADD64ri32 killed renamable $rbx, 12, implicit-def $eflags, debug-location !16 + $rdi = MOV64rr $rbx, debug-location !17 + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !17 + CALL64pcrel32 @getlong, csr_64, implicit $rsp, implicit $ssp, implicit-def $rax, debug-location !18 + CMP64ri8 killed renamable $rax, 0, implicit-def $eflags, debug-location !18 + JCC_1 %bb.2, 4, implicit $eflags, debug-location !20 + + bb.1.if.then: + liveins: $rbx, $r14 + + renamable $rbx = ADD64ri32 killed renamable $rbx, 1, implicit-def $eflags, debug-location !21 + + bb.2.if.end: + liveins: $rbx, $r14 + + DBG_PHI $rbx, 1 + $rax = COPY $rbx + $rbx = MOV64ri 0 + DBG_INSTR_REF 1, 0, !12, !DIExpression(), debug-location !13 + + ; This sequence should mark the contents of rbx on block entry as being the + ; value for the variable at this DBG_INSTR_REF. We've force it to be in + ; $rax now, so we should see a DBG_VALUE for rax: + ; CHECK: DBG_PHI $rbx, 1 + ; CHECK-NEXT: $rax = COPY $rbx + ; CHECK-NEXT: $rbx = MOV64ri 0 + ; CHECK-NEXT: DBG_INSTR_REF 1, 0 + ; CHECK-NEXT: DBG_VALUE $rax, $noreg + + $rbx = COPY $rax + renamable $rbx = ADD64rr killed renamable $rbx, killed renamable $r14, implicit-def $eflags, debug-location !23 + DBG_VALUE $rbx, $noreg, !12, !DIExpression(), debug-location !13 + $rdi = MOV64rr $rbx, debug-location !24 + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !24 + $eax = MOV32rr $ebx, implicit killed $rbx, debug-location !26 + $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags, debug-location !26 + CFI_INSTRUCTION def_cfa_offset 24, debug-location !26 + $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !26 + CFI_INSTRUCTION def_cfa_offset 16, debug-location !26 + $r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !26 + CFI_INSTRUCTION def_cfa_offset 8, debug-location !26 + RETQ implicit $eax, debug-location !26 + +... Index: llvm/test/DebugInfo/MIR/InstrRef/dbg-phis-merging-in-ldv.mir =================================================================== --- /dev/null +++ llvm/test/DebugInfo/MIR/InstrRef/dbg-phis-merging-in-ldv.mir @@ -0,0 +1,199 @@ +# RUN: llc %s -o - -mtriple=x86_64-unknown-unknown \ +# RUN: -experimental-debug-variable-locations -run-pass=livedebugvalues \ +# RUN: | FileCheck %s --check-prefix=CHECK +# +# Test that, in a scenario where tail duplication has duplicated DBG_PHI +# instructions, we can reconstruct the value to refer to. This includes cases +# where the DBG_PHIs refer to the same value, to values that later merge, and +# value that become unavailable. +--- | + ; ModuleID = 'before.mir' + source_filename = "test.c" + target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" + target triple = "x86_64-unknown-linux-gnu" + + define dso_local i32 @foo(i64 %bar, i64 %baz) !dbg !7 { + entry: + call void @llvm.dbg.value(metadata i64 %bar, metadata !12, metadata !DIExpression()), !dbg !13 + call void @llvm.dbg.value(metadata i64 %baz, metadata !14, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %bar), !dbg !15 + %add = add nsw i64 %bar, 12, !dbg !16 + call void @llvm.dbg.value(metadata i64 %add, metadata !12, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %add), !dbg !17 + %add1 = add nsw i64 %baz, 1, !dbg !18 + call void @llvm.dbg.value(metadata i64 %add1, metadata !14, metadata !DIExpression()), !dbg !13 + %call = call i64 @getlong(), !dbg !19 + %tobool = icmp ne i64 %call, 0, !dbg !19 + br i1 %tobool, label %if.then, label %if.else, !dbg !21 + + if.then: ; preds = %entry + %add2 = add nsw i64 %add, 1, !dbg !22 + call void @llvm.dbg.value(metadata i64 %add2, metadata !12, metadata !DIExpression()), !dbg !13 + br label %if.end, !dbg !24 + + if.else: ; preds = %entry + %add3 = add nsw i64 %add, 2, !dbg !25 + call void @llvm.dbg.value(metadata i64 %add3, metadata !12, metadata !DIExpression()), !dbg !13 + br label %if.end + + if.end: ; preds = %if.else, %if.then + %bar.addr.0 = phi i64 [ %add2, %if.then ], [ %add3, %if.else ], !dbg !27 + call void @llvm.dbg.value(metadata i64 %bar.addr.0, metadata !12, metadata !DIExpression()), !dbg !13 + %add4 = add nsw i64 %bar.addr.0, %add1, !dbg !28 + call void @llvm.dbg.value(metadata i64 %add4, metadata !12, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %add4), !dbg !29 + %conv = trunc i64 %add4 to i32, !dbg !30 + ret i32 %conv, !dbg !31 + } + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.declare(metadata, metadata, metadata) + + declare dso_local void @ext(i64) + + declare dso_local i64 @getlong() + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.value(metadata, metadata, metadata) + + !llvm.dbg.cu = !{!0} + !llvm.module.flags = !{!3, !4, !5} + !llvm.ident = !{!6} + + !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None) + !1 = !DIFile(filename: "test.c", directory: ".") + !2 = !{} + !3 = !{i32 7, !"Dwarf Version", i32 4} + !4 = !{i32 2, !"Debug Info Version", i32 3} + !5 = !{i32 1, !"wchar_size", i32 4} + !6 = !{!"clang"} + !7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !8, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2) + !8 = !DISubroutineType(types: !9) + !9 = !{!10, !11, !11} + !10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !11 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed) + !12 = !DILocalVariable(name: "bar", arg: 1, scope: !7, file: !1, line: 3, type: !11) + !13 = !DILocation(line: 0, scope: !7) + !14 = !DILocalVariable(name: "baz", arg: 2, scope: !7, file: !1, line: 3, type: !11) + !15 = !DILocation(line: 4, column: 3, scope: !7) + !16 = !DILocation(line: 5, column: 7, scope: !7) + !17 = !DILocation(line: 6, column: 3, scope: !7) + !18 = !DILocation(line: 7, column: 7, scope: !7) + !19 = !DILocation(line: 9, column: 7, scope: !20) + !20 = distinct !DILexicalBlock(scope: !7, file: !1, line: 9, column: 7) + !21 = !DILocation(line: 9, column: 7, scope: !7) + !22 = !DILocation(line: 10, column: 9, scope: !23) + !23 = distinct !DILexicalBlock(scope: !20, file: !1, line: 9, column: 18) + !24 = !DILocation(line: 11, column: 3, scope: !23) + !25 = !DILocation(line: 12, column: 9, scope: !26) + !26 = distinct !DILexicalBlock(scope: !20, file: !1, line: 11, column: 10) + !27 = !DILocation(line: 0, scope: !20) + !28 = !DILocation(line: 15, column: 7, scope: !7) + !29 = !DILocation(line: 16, column: 3, scope: !7) + !30 = !DILocation(line: 17, column: 10, scope: !7) + !31 = !DILocation(line: 17, column: 3, scope: !7) + +... +--- +name: foo +alignment: 16 +tracksRegLiveness: true +liveins: + - { reg: '$rdi' } + - { reg: '$rsi' } +frameInfo: + stackSize: 24 + offsetAdjustment: -24 + maxAlignment: 1 + adjustsStack: true + hasCalls: true + maxCallFrameSize: 0 + cvBytesOfCalleeSavedRegisters: 16 +fixedStack: + - { id: 0, type: spill-slot, offset: -24, size: 8, alignment: 8, callee-saved-register: '$rbx' } + - { id: 1, type: spill-slot, offset: -16, size: 8, alignment: 16, callee-saved-register: '$r14' } +machineFunctionInfo: {} +body: | + bb.0.entry: + successors: %bb.2, %bb.1 + liveins: $rdi, $rsi, $r14, $rbx + + frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 16 + frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 24 + frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 32 + CFI_INSTRUCTION offset $rbx, -24 + CFI_INSTRUCTION offset $r14, -16 + $r14 = MOV64rr $rsi + $rbx = MOV64rr $rdi + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !15 + renamable $rbx = ADD64ri32 killed renamable $rbx, 12, implicit-def $eflags, debug-location !16 + $rdi = MOV64rr $rbx, debug-location !17 + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !17 + renamable $r14 = ADD64ri32 killed renamable $r14, 1, implicit-def $eflags, debug-location !18 + CALL64pcrel32 @getlong, csr_64, implicit $rsp, implicit $ssp, implicit-def $rax, debug-location !19 + CMP64ri8 killed renamable $rax, 0, implicit-def $eflags, debug-location !19 + JCC_1 %bb.1, 5, implicit $eflags, debug-location !21 + + bb.2.if.else: + liveins: $rbx, $r14, $rax + + renamable $rbx = ADD64ri32 killed renamable $rbx, 2, implicit-def $eflags, debug-location !25 + DBG_PHI $r14, 1 + DBG_PHI $rbx, 2 + DBG_PHI $rax, 3 + $rax = MOV64ri 0 + JMP_1 %bb.3 + + bb.1.if.then: + liveins: $rbx, $r14, $rax + + renamable $rbx = ADD64ri32 killed renamable $rbx, 1, implicit-def $eflags, debug-location !22 + DBG_PHI $r14, 1 + DBG_PHI $rbx, 2 + DBG_PHI $rax, 3 + + bb.3.if.end: + liveins: $rbx, $r14 + + DBG_INSTR_REF 1, 0, !14, !DIExpression(), debug-location !13 + DBG_INSTR_REF 2, 0, !12, !DIExpression(), debug-location !13 + DBG_INSTR_REF 3, 0, !12, !DIExpression(), debug-location !13 + + ; Value number 1 is live-through the above control flow from the two + ; DBG_PHIs: + ; CHECK: DBG_INSTR_REF 1, 0 + ; CHECK-NEXT: DBG_VALUE $r14 + ; + ; While value number 2 has different defs that merge on entry to bb.3. + ; These are both in $rbx though, and we should find its location: + ; CHECK: DBG_INSTR_REF 2, 0 + ; CHECK-NEXT: DBG_VALUE $rbx + ; + ; Value number 3 cannot be resolved because $rax is clobbered in bb.2, + ; meaning the merged value in bb.3 is incorrect. It should produce a + ; DBG_VALUE $noreg. + ; CHECK: DBG_INSTR_REF 3, 0 + ; CHECK-NEXT: DBG_VALUE $noreg + + renamable $rbx = ADD64rr killed renamable $rbx, killed renamable $r14, implicit-def $eflags, debug-location !28 + DBG_INSTR_REF 2, 0, !12, !DIExpression(), debug-location !13 + + ; After clobbering rbx, the variable location should not be available. + ; CHECK: DBG_INSTR_REF 2, 0 + ; CHECK-NEXT: DBG_VALUE $noreg + + $rdi = MOV64rr $rbx, debug-location !29 + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !29 + $eax = MOV32rr $ebx, implicit killed $rbx, debug-location !31 + $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags, debug-location !31 + CFI_INSTRUCTION def_cfa_offset 24, debug-location !31 + $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !31 + CFI_INSTRUCTION def_cfa_offset 16, debug-location !31 + $r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !31 + CFI_INSTRUCTION def_cfa_offset 8, debug-location !31 + RETQ implicit $eax, debug-location !31 + +... Index: llvm/test/DebugInfo/MIR/InstrRef/dbg-phis-with-loops.mir =================================================================== --- /dev/null +++ llvm/test/DebugInfo/MIR/InstrRef/dbg-phis-with-loops.mir @@ -0,0 +1,205 @@ +# RUN: llc %s -o - -mtriple=x86_64-unknown-unknown \ +# RUN: -experimental-debug-variable-locations -run-pass=livedebugvalues \ +# RUN: | FileCheck %s --check-prefix=CHECK +# +# Copy of dbg-phis-merging-in-ldv.mir, where I've added a loop in between the +# DBG_PHI "definitions" of values, and the DBG_INSTR_REFs where they're used. +# We should be able to traverse this obstacle. +--- | + ; ModuleID = 'before.mir' + source_filename = "test.c" + target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" + target triple = "x86_64-unknown-linux-gnu" + + define dso_local i32 @foo(i64 %bar, i64 %baz) !dbg !7 { + entry: + call void @llvm.dbg.value(metadata i64 %bar, metadata !12, metadata !DIExpression()), !dbg !13 + call void @llvm.dbg.value(metadata i64 %baz, metadata !14, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %bar), !dbg !15 + %add = add nsw i64 %bar, 12, !dbg !16 + call void @llvm.dbg.value(metadata i64 %add, metadata !12, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %add), !dbg !17 + %add1 = add nsw i64 %baz, 1, !dbg !18 + call void @llvm.dbg.value(metadata i64 %add1, metadata !14, metadata !DIExpression()), !dbg !13 + %call = call i64 @getlong(), !dbg !19 + %tobool = icmp ne i64 %call, 0, !dbg !19 + br i1 %tobool, label %if.then, label %if.else, !dbg !21 + + if.then: ; preds = %entry + %add2 = add nsw i64 %add, 1, !dbg !22 + call void @llvm.dbg.value(metadata i64 %add2, metadata !12, metadata !DIExpression()), !dbg !13 + br label %if.end, !dbg !24 + + if.else: ; preds = %entry + %add3 = add nsw i64 %add, 2, !dbg !25 + call void @llvm.dbg.value(metadata i64 %add3, metadata !12, metadata !DIExpression()), !dbg !13 + br label %if.end + + if.end: ; preds = %if.else, %if.then + %bar.addr.0 = phi i64 [ %add2, %if.then ], [ %add3, %if.else ], !dbg !27 + call void @llvm.dbg.value(metadata i64 %bar.addr.0, metadata !12, metadata !DIExpression()), !dbg !13 + %add4 = add nsw i64 %bar.addr.0, %add1, !dbg !28 + call void @llvm.dbg.value(metadata i64 %add4, metadata !12, metadata !DIExpression()), !dbg !13 + call void @ext(i64 %add4), !dbg !29 + %conv = trunc i64 %add4 to i32, !dbg !30 + ret i32 %conv, !dbg !31 + } + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.declare(metadata, metadata, metadata) #0 + + declare dso_local void @ext(i64) + + declare dso_local i64 @getlong() + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.value(metadata, metadata, metadata) #0 + + attributes #0 = { nounwind readnone speculatable willreturn } + + !llvm.dbg.cu = !{!0} + !llvm.module.flags = !{!3, !4, !5} + !llvm.ident = !{!6} + + !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None) + !1 = !DIFile(filename: "test.c", directory: ".") + !2 = !{} + !3 = !{i32 7, !"Dwarf Version", i32 4} + !4 = !{i32 2, !"Debug Info Version", i32 3} + !5 = !{i32 1, !"wchar_size", i32 4} + !6 = !{!"clang"} + !7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !8, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2) + !8 = !DISubroutineType(types: !9) + !9 = !{!10, !11, !11} + !10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !11 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed) + !12 = !DILocalVariable(name: "bar", arg: 1, scope: !7, file: !1, line: 3, type: !11) + !13 = !DILocation(line: 0, scope: !7) + !14 = !DILocalVariable(name: "baz", arg: 2, scope: !7, file: !1, line: 3, type: !11) + !15 = !DILocation(line: 4, column: 3, scope: !7) + !16 = !DILocation(line: 5, column: 7, scope: !7) + !17 = !DILocation(line: 6, column: 3, scope: !7) + !18 = !DILocation(line: 7, column: 7, scope: !7) + !19 = !DILocation(line: 9, column: 7, scope: !20) + !20 = distinct !DILexicalBlock(scope: !7, file: !1, line: 9, column: 7) + !21 = !DILocation(line: 9, column: 7, scope: !7) + !22 = !DILocation(line: 10, column: 9, scope: !23) + !23 = distinct !DILexicalBlock(scope: !20, file: !1, line: 9, column: 18) + !24 = !DILocation(line: 11, column: 3, scope: !23) + !25 = !DILocation(line: 12, column: 9, scope: !26) + !26 = distinct !DILexicalBlock(scope: !20, file: !1, line: 11, column: 10) + !27 = !DILocation(line: 0, scope: !20) + !28 = !DILocation(line: 15, column: 7, scope: !7) + !29 = !DILocation(line: 16, column: 3, scope: !7) + !30 = !DILocation(line: 17, column: 10, scope: !7) + !31 = !DILocation(line: 17, column: 3, scope: !7) + +... +--- +name: foo +alignment: 16 +tracksRegLiveness: true +liveins: + - { reg: '$rdi' } + - { reg: '$rsi' } +frameInfo: + stackSize: 24 + offsetAdjustment: -24 + maxAlignment: 1 + adjustsStack: true + hasCalls: true + maxCallFrameSize: 0 + cvBytesOfCalleeSavedRegisters: 16 +fixedStack: + - { id: 0, type: spill-slot, offset: -24, size: 8, alignment: 8, callee-saved-register: '$rbx' } + - { id: 1, type: spill-slot, offset: -16, size: 8, alignment: 16, callee-saved-register: '$r14' } +machineFunctionInfo: {} +body: | + bb.0.entry: + successors: %bb.2, %bb.1 + liveins: $rdi, $rsi, $r14, $rbx + + frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 16 + frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 24 + frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp + CFI_INSTRUCTION def_cfa_offset 32 + CFI_INSTRUCTION offset $rbx, -24 + CFI_INSTRUCTION offset $r14, -16 + $r14 = MOV64rr $rsi + $rbx = MOV64rr $rdi + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !15 + renamable $rbx = ADD64ri32 killed renamable $rbx, 12, implicit-def $eflags, debug-location !16 + $rdi = MOV64rr $rbx, debug-location !17 + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !17 + renamable $r14 = ADD64ri32 killed renamable $r14, 1, implicit-def $eflags, debug-location !18 + CALL64pcrel32 @getlong, csr_64, implicit $rsp, implicit $ssp, implicit-def $rax, debug-location !19 + CMP64ri8 killed renamable $rax, 0, implicit-def $eflags, debug-location !19 + JCC_1 %bb.1, 5, implicit $eflags, debug-location !21 + + bb.2.if.else: + liveins: $rbx, $r14, $rax + + renamable $rbx = ADD64ri32 killed renamable $rbx, 2, implicit-def $eflags, debug-location !25 + DBG_PHI $r14, 1 + DBG_PHI $rbx, 2 + DBG_PHI $rax, 3 + $rax = MOV64ri 0 + JMP_1 %bb.3 + + bb.1.if.then: + liveins: $rbx, $r14, $rax + + renamable $rbx = ADD64ri32 killed renamable $rbx, 1, implicit-def $eflags, debug-location !22 + DBG_PHI $r14, 1 + DBG_PHI $rbx, 2 + DBG_PHI $rax, 3 + + bb.3: + $r15 = MOV64ri 0 + CMP64ri8 $r15, 0, implicit-def $eflags, debug-location !19 + JCC_1 %bb.3, 5, implicit $eflags, debug-location !21 + + bb.4: + liveins: $rbx, $r14 + + DBG_INSTR_REF 1, 0, !14, !DIExpression(), debug-location !13 + DBG_INSTR_REF 2, 0, !12, !DIExpression(), debug-location !13 + DBG_INSTR_REF 3, 0, !12, !DIExpression(), debug-location !13 + + ; Value number 1 is live-through the above control flow from the two + ; DBG_PHIs: + ; CHECK: DBG_INSTR_REF 1, 0 + ; CHECK-NEXT: DBG_VALUE $r14 + ; + ; While value number 2 has different defs that merge on entry to bb.3. + ; These are both in $rbx though, and we should find its location: + ; CHECK: DBG_INSTR_REF 2, 0 + ; CHECK-NEXT: DBG_VALUE $rbx + ; + ; Value number 3 cannot be resolved because $rax is clobbered in bb.2, + ; meaning the merged value in bb.3 is incorrect. It should produce a + ; DBG_VALUE $noreg. + ; CHECK: DBG_INSTR_REF 3, 0 + ; CHECK-NEXT: DBG_VALUE $noreg + + renamable $rbx = ADD64rr killed renamable $rbx, killed renamable $r14, implicit-def $eflags, debug-location !28 + DBG_INSTR_REF 2, 0, !12, !DIExpression(), debug-location !13 + + ; After clobbering rbx, the variable location should not be available. + ; CHECK: DBG_INSTR_REF 2, 0 + ; CHECK-NEXT: DBG_VALUE $noreg + + $rdi = MOV64rr $rbx, debug-location !29 + CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, debug-location !29 + $eax = MOV32rr $ebx, implicit killed $rbx, debug-location !31 + $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags, debug-location !31 + CFI_INSTRUCTION def_cfa_offset 24, debug-location !31 + $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !31 + CFI_INSTRUCTION def_cfa_offset 16, debug-location !31 + $r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !31 + CFI_INSTRUCTION def_cfa_offset 8, debug-location !31 + RETQ implicit $eax, debug-location !31 + +...