diff options
Diffstat (limited to 'llvm/lib/CodeGen/LiveDebugVariables.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/LiveDebugVariables.cpp | 996 |
1 files changed, 718 insertions, 278 deletions
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp index 2325341070a3..54058a547928 100644 --- a/llvm/lib/CodeGen/LiveDebugVariables.cpp +++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp @@ -38,9 +38,11 @@ #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineOperand.h" #include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/SlotIndexes.h" #include "llvm/CodeGen/TargetInstrInfo.h" #include "llvm/CodeGen/TargetOpcodes.h" +#include "llvm/CodeGen/TargetPassConfig.h" #include "llvm/CodeGen/TargetRegisterInfo.h" #include "llvm/CodeGen/TargetSubtargetInfo.h" #include "llvm/CodeGen/VirtRegMap.h" @@ -56,6 +58,7 @@ #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetMachine.h" #include <algorithm> #include <cassert> #include <iterator> @@ -100,30 +103,134 @@ namespace { /// with some flags about the original usage of the location. class DbgVariableValue { public: - DbgVariableValue(unsigned LocNo, bool WasIndirect, - const DIExpression &Expression) - : LocNo(LocNo), WasIndirect(WasIndirect), Expression(&Expression) { - assert(getLocNo() == LocNo && "location truncation"); + DbgVariableValue(ArrayRef<unsigned> NewLocs, bool WasIndirect, bool WasList, + const DIExpression &Expr) + : WasIndirect(WasIndirect), WasList(WasList), Expression(&Expr) { + assert(!(WasIndirect && WasList) && + "DBG_VALUE_LISTs should not be indirect."); + SmallVector<unsigned> LocNoVec; + for (unsigned LocNo : NewLocs) { + auto It = find(LocNoVec, LocNo); + if (It == LocNoVec.end()) + LocNoVec.push_back(LocNo); + else { + // Loc duplicates an element in LocNos; replace references to Op + // with references to the duplicating element. + unsigned OpIdx = LocNoVec.size(); + unsigned DuplicatingIdx = std::distance(LocNoVec.begin(), It); + Expression = + DIExpression::replaceArg(Expression, OpIdx, DuplicatingIdx); + } + } + // FIXME: Debug values referencing 64+ unique machine locations are rare and + // currently unsupported for performance reasons. If we can verify that + // performance is acceptable for such debug values, we can increase the + // bit-width of LocNoCount to 14 to enable up to 16384 unique machine + // locations. We will also need to verify that this does not cause issues + // with LiveDebugVariables' use of IntervalMap. + if (LocNoVec.size() < 64) { + LocNoCount = LocNoVec.size(); + if (LocNoCount > 0) { + LocNos = std::make_unique<unsigned[]>(LocNoCount); + std::copy(LocNoVec.begin(), LocNoVec.end(), loc_nos_begin()); + } + } else { + LLVM_DEBUG(dbgs() << "Found debug value with 64+ unique machine " + "locations, dropping...\n"); + LocNoCount = 1; + // Turn this into an undef debug value list; right now, the simplest form + // of this is an expression with one arg, and an undef debug operand. + Expression = + DIExpression::get(Expr.getContext(), {dwarf::DW_OP_LLVM_arg, 0, + dwarf::DW_OP_stack_value}); + if (auto FragmentInfoOpt = Expr.getFragmentInfo()) + Expression = *DIExpression::createFragmentExpression( + Expression, FragmentInfoOpt->OffsetInBits, + FragmentInfoOpt->SizeInBits); + LocNos = std::make_unique<unsigned[]>(LocNoCount); + LocNos[0] = UndefLocNo; + } } - DbgVariableValue() : LocNo(0), WasIndirect(0) {} + DbgVariableValue() : LocNoCount(0), WasIndirect(0), WasList(0) {} + DbgVariableValue(const DbgVariableValue &Other) + : LocNoCount(Other.LocNoCount), WasIndirect(Other.getWasIndirect()), + WasList(Other.getWasList()), Expression(Other.getExpression()) { + if (Other.getLocNoCount()) { + LocNos.reset(new unsigned[Other.getLocNoCount()]); + std::copy(Other.loc_nos_begin(), Other.loc_nos_end(), loc_nos_begin()); + } + } + + DbgVariableValue &operator=(const DbgVariableValue &Other) { + if (this == &Other) + return *this; + if (Other.getLocNoCount()) { + LocNos.reset(new unsigned[Other.getLocNoCount()]); + std::copy(Other.loc_nos_begin(), Other.loc_nos_end(), loc_nos_begin()); + } else { + LocNos.release(); + } + LocNoCount = Other.getLocNoCount(); + WasIndirect = Other.getWasIndirect(); + WasList = Other.getWasList(); + Expression = Other.getExpression(); + return *this; + } const DIExpression *getExpression() const { return Expression; } - unsigned getLocNo() const { - // Fix up the undef location number, which gets truncated. - return LocNo == INT_MAX ? UndefLocNo : LocNo; + uint8_t getLocNoCount() const { return LocNoCount; } + bool containsLocNo(unsigned LocNo) const { + return is_contained(loc_nos(), LocNo); } bool getWasIndirect() const { return WasIndirect; } - bool isUndef() const { return getLocNo() == UndefLocNo; } + bool getWasList() const { return WasList; } + bool isUndef() const { return LocNoCount == 0 || containsLocNo(UndefLocNo); } + + DbgVariableValue decrementLocNosAfterPivot(unsigned Pivot) const { + SmallVector<unsigned, 4> NewLocNos; + for (unsigned LocNo : loc_nos()) + NewLocNos.push_back(LocNo != UndefLocNo && LocNo > Pivot ? LocNo - 1 + : LocNo); + return DbgVariableValue(NewLocNos, WasIndirect, WasList, *Expression); + } - DbgVariableValue changeLocNo(unsigned NewLocNo) const { - return DbgVariableValue(NewLocNo, WasIndirect, *Expression); + DbgVariableValue remapLocNos(ArrayRef<unsigned> LocNoMap) const { + SmallVector<unsigned> NewLocNos; + for (unsigned LocNo : loc_nos()) + // Undef values don't exist in locations (and thus not in LocNoMap + // either) so skip over them. See getLocationNo(). + NewLocNos.push_back(LocNo == UndefLocNo ? UndefLocNo : LocNoMap[LocNo]); + return DbgVariableValue(NewLocNos, WasIndirect, WasList, *Expression); + } + + DbgVariableValue changeLocNo(unsigned OldLocNo, unsigned NewLocNo) const { + SmallVector<unsigned> NewLocNos; + NewLocNos.assign(loc_nos_begin(), loc_nos_end()); + auto OldLocIt = find(NewLocNos, OldLocNo); + assert(OldLocIt != NewLocNos.end() && "Old location must be present."); + *OldLocIt = NewLocNo; + return DbgVariableValue(NewLocNos, WasIndirect, WasList, *Expression); + } + + bool hasLocNoGreaterThan(unsigned LocNo) const { + return any_of(loc_nos(), + [LocNo](unsigned ThisLocNo) { return ThisLocNo > LocNo; }); + } + + void printLocNos(llvm::raw_ostream &OS) const { + for (const unsigned &Loc : loc_nos()) + OS << (&Loc == loc_nos_begin() ? " " : ", ") << Loc; } friend inline bool operator==(const DbgVariableValue &LHS, const DbgVariableValue &RHS) { - return LHS.LocNo == RHS.LocNo && LHS.WasIndirect == RHS.WasIndirect && - LHS.Expression == RHS.Expression; + if (std::tie(LHS.LocNoCount, LHS.WasIndirect, LHS.WasList, + LHS.Expression) != + std::tie(RHS.LocNoCount, RHS.WasIndirect, RHS.WasList, RHS.Expression)) + return false; + return std::equal(LHS.loc_nos_begin(), LHS.loc_nos_end(), + RHS.loc_nos_begin()); } friend inline bool operator!=(const DbgVariableValue &LHS, @@ -131,9 +238,24 @@ public: return !(LHS == RHS); } + unsigned *loc_nos_begin() { return LocNos.get(); } + const unsigned *loc_nos_begin() const { return LocNos.get(); } + unsigned *loc_nos_end() { return LocNos.get() + LocNoCount; } + const unsigned *loc_nos_end() const { return LocNos.get() + LocNoCount; } + ArrayRef<unsigned> loc_nos() const { + return ArrayRef<unsigned>(LocNos.get(), LocNoCount); + } + private: - unsigned LocNo : 31; - unsigned WasIndirect : 1; + // IntervalMap requires the value object to be very small, to the extent + // that we do not have enough room for an std::vector. Using a C-style array + // (with a unique_ptr wrapper for convenience) allows us to optimize for this + // specific case by packing the array size into only 6 bits (it is highly + // unlikely that any debug value will need 64+ locations). + std::unique_ptr<unsigned[]> LocNos; + uint8_t LocNoCount : 6; + bool WasIndirect : 1; + bool WasList : 1; const DIExpression *Expression = nullptr; }; } // namespace @@ -145,6 +267,14 @@ using LocMap = IntervalMap<SlotIndex, DbgVariableValue, 4>; /// Non-spilled locations are not added to the map. using SpillOffsetMap = DenseMap<unsigned, unsigned>; +/// Cache to save the location where it can be used as the starting +/// position as input for calling MachineBasicBlock::SkipPHIsLabelsAndDebug. +/// This is to prevent MachineBasicBlock::SkipPHIsLabelsAndDebug from +/// repeatedly searching the same set of PHIs/Labels/Debug instructions +/// if it is called many times for the same block. +using BlockSkipInstsMap = + DenseMap<MachineBasicBlock *, MachineBasicBlock::iterator>; + namespace { class LDVImpl; @@ -179,9 +309,11 @@ class UserValue { /// Insert a DBG_VALUE into MBB at Idx for DbgValue. void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx, SlotIndex StopIdx, DbgVariableValue DbgValue, - bool Spilled, unsigned SpillOffset, LiveIntervals &LIS, + ArrayRef<bool> LocSpills, + ArrayRef<unsigned> SpillOffsets, LiveIntervals &LIS, const TargetInstrInfo &TII, - const TargetRegisterInfo &TRI); + const TargetRegisterInfo &TRI, + BlockSkipInstsMap &BBSkipInstsMap); /// Replace OldLocNo ranges with NewRegs ranges where NewRegs /// is live. Returns true if any changes were made. @@ -264,17 +396,17 @@ public: void removeLocationIfUnused(unsigned LocNo) { // Bail out if LocNo still is used. for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) { - DbgVariableValue DbgValue = I.value(); - if (DbgValue.getLocNo() == LocNo) + const DbgVariableValue &DbgValue = I.value(); + if (DbgValue.containsLocNo(LocNo)) return; } // Remove the entry in the locations vector, and adjust all references to // location numbers above the removed entry. locations.erase(locations.begin() + LocNo); for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) { - DbgVariableValue DbgValue = I.value(); - if (!DbgValue.isUndef() && DbgValue.getLocNo() > LocNo) - I.setValueUnchecked(DbgValue.changeLocNo(DbgValue.getLocNo() - 1)); + const DbgVariableValue &DbgValue = I.value(); + if (DbgValue.hasLocNoGreaterThan(LocNo)) + I.setValueUnchecked(DbgValue.decrementLocNosAfterPivot(LocNo)); } } @@ -282,16 +414,19 @@ public: void mapVirtRegs(LDVImpl *LDV); /// Add a definition point to this user value. - void addDef(SlotIndex Idx, const MachineOperand &LocMO, bool IsIndirect, - const DIExpression &Expr) { - DbgVariableValue DbgValue(getLocationNo(LocMO), IsIndirect, Expr); + void addDef(SlotIndex Idx, ArrayRef<MachineOperand> LocMOs, bool IsIndirect, + bool IsList, const DIExpression &Expr) { + SmallVector<unsigned> Locs; + for (MachineOperand Op : LocMOs) + Locs.push_back(getLocationNo(Op)); + DbgVariableValue DbgValue(Locs, IsIndirect, IsList, Expr); // Add a singular (Idx,Idx) -> value mapping. LocMap::iterator I = locInts.find(Idx); if (!I.valid() || I.start() != Idx) - I.insert(Idx, Idx.getNextSlot(), DbgValue); + I.insert(Idx, Idx.getNextSlot(), std::move(DbgValue)); else // A later DBG_VALUE at the same SlotIndex overrides the old location. - I.setValue(DbgValue); + I.setValue(std::move(DbgValue)); } /// Extend the current definition as far as possible down. @@ -304,25 +439,30 @@ public: /// /// \param Idx Starting point for the definition. /// \param DbgValue value to propagate. - /// \param LR Restrict liveness to where LR has the value VNI. May be null. - /// \param VNI When LR is not null, this is the value to restrict to. + /// \param LiveIntervalInfo For each location number key in this map, + /// restricts liveness to where the LiveRange has the value equal to the\ + /// VNInfo. /// \param [out] Kills Append end points of VNI's live range to Kills. /// \param LIS Live intervals analysis. - void extendDef(SlotIndex Idx, DbgVariableValue DbgValue, LiveRange *LR, - const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills, + void extendDef(SlotIndex Idx, DbgVariableValue DbgValue, + SmallDenseMap<unsigned, std::pair<LiveRange *, const VNInfo *>> + &LiveIntervalInfo, + Optional<std::pair<SlotIndex, SmallVector<unsigned>>> &Kills, LiveIntervals &LIS); /// The value in LI may be copies to other registers. Determine if /// any of the copies are available at the kill points, and add defs if /// possible. /// - /// \param LI Scan for copies of the value in LI->reg. /// \param DbgValue Location number of LI->reg, and DIExpression. - /// \param Kills Points where the range of DbgValue could be extended. + /// \param LocIntervals Scan for copies of the value for each location in the + /// corresponding LiveInterval->reg. + /// \param KilledAt The point where the range of DbgValue could be extended. /// \param [in,out] NewDefs Append (Idx, DbgValue) of inserted defs here. void addDefsFromCopies( - LiveInterval *LI, DbgVariableValue DbgValue, - const SmallVectorImpl<SlotIndex> &Kills, + DbgVariableValue DbgValue, + SmallVectorImpl<std::pair<unsigned, LiveInterval *>> &LocIntervals, + SlotIndex KilledAt, SmallVectorImpl<std::pair<SlotIndex, DbgVariableValue>> &NewDefs, MachineRegisterInfo &MRI, LiveIntervals &LIS); @@ -348,10 +488,11 @@ public: void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, const TargetInstrInfo &TII, const TargetRegisterInfo &TRI, - const SpillOffsetMap &SpillOffsets); + const SpillOffsetMap &SpillOffsets, + BlockSkipInstsMap &BBSkipInstsMap); /// Return DebugLoc of this UserValue. - DebugLoc getDebugLoc() { return dl;} + const DebugLoc &getDebugLoc() { return dl; } void print(raw_ostream &, const TargetRegisterInfo *); }; @@ -365,7 +506,8 @@ class UserLabel { /// Insert a DBG_LABEL into MBB at Idx. void insertDebugLabel(MachineBasicBlock *MBB, SlotIndex Idx, - LiveIntervals &LIS, const TargetInstrInfo &TII); + LiveIntervals &LIS, const TargetInstrInfo &TII, + BlockSkipInstsMap &BBSkipInstsMap); public: /// Create a new UserLabel. @@ -379,10 +521,11 @@ public: } /// Recreate DBG_LABEL instruction from data structures. - void emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII); + void emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII, + BlockSkipInstsMap &BBSkipInstsMap); /// Return DebugLoc of this UserLabel. - DebugLoc getDebugLoc() { return dl; } + const DebugLoc &getDebugLoc() { return dl; } void print(raw_ostream &, const TargetRegisterInfo *); }; @@ -395,10 +538,31 @@ class LDVImpl { LiveIntervals *LIS; const TargetRegisterInfo *TRI; - using StashedInstrRef = - std::tuple<unsigned, unsigned, const DILocalVariable *, - const DIExpression *, DebugLoc>; - std::map<SlotIndex, std::vector<StashedInstrRef>> StashedInstrReferences; + /// Position and VReg of a PHI instruction during register allocation. + struct PHIValPos { + SlotIndex SI; /// Slot where this PHI occurs. + Register Reg; /// VReg this PHI occurs in. + unsigned SubReg; /// Qualifiying subregister for Reg. + }; + + /// Map from debug instruction number to PHI position during allocation. + std::map<unsigned, PHIValPos> PHIValToPos; + /// Index of, for each VReg, which debug instruction numbers and corresponding + /// PHIs are sensitive to splitting. Each VReg may have multiple PHI defs, + /// at different positions. + DenseMap<Register, std::vector<unsigned>> RegToPHIIdx; + + /// Record for any debug instructions unlinked from their blocks during + /// regalloc. Stores the instr and it's location, so that they can be + /// re-inserted after regalloc is over. + struct InstrPos { + MachineInstr *MI; ///< Debug instruction, unlinked from it's block. + SlotIndex Idx; ///< Slot position where MI should be re-inserted. + MachineBasicBlock *MBB; ///< Block that MI was in. + }; + + /// Collection of stored debug instructions, preserved until after regalloc. + SmallVector<InstrPos, 32> StashedDebugInstrs; /// Whether emitDebugValues is called. bool EmitDone = false; @@ -436,15 +600,18 @@ class LDVImpl { /// \returns True if the DBG_VALUE instruction should be deleted. bool handleDebugValue(MachineInstr &MI, SlotIndex Idx); - /// Track a DBG_INSTR_REF. This needs to be removed from the MachineFunction - /// during regalloc -- but there's no need to maintain live ranges, as we - /// refer to a value rather than a location. + /// Track variable location debug instructions while using the instruction + /// referencing implementation. Such debug instructions do not need to be + /// updated during regalloc because they identify instructions rather than + /// register locations. However, they needs to be removed from the + /// MachineFunction during regalloc, then re-inserted later, to avoid + /// disrupting the allocator. /// - /// \param MI DBG_INSTR_REF instruction + /// \param MI Any DBG_VALUE / DBG_INSTR_REF / DBG_PHI instruction /// \param Idx Last valid SlotIndex before instruction /// - /// \returns True if the DBG_VALUE instruction should be deleted. - bool handleDebugInstrRef(MachineInstr &MI, SlotIndex Idx); + /// \returns Iterator to continue processing from after unlinking. + MachineBasicBlock::iterator handleDebugInstr(MachineInstr &MI, SlotIndex Idx); /// Add DBG_LABEL instruction to UserLabel. /// @@ -458,9 +625,11 @@ class LDVImpl { /// for each instruction. /// /// \param mf MachineFunction to be scanned. + /// \param InstrRef Whether to operate in instruction referencing mode. If + /// true, most of LiveDebugVariables doesn't run. /// /// \returns True if any debug values were found. - bool collectDebugValues(MachineFunction &mf); + bool collectDebugValues(MachineFunction &mf, bool InstrRef); /// Compute the live intervals of all user values after collecting all /// their def points. @@ -469,12 +638,14 @@ class LDVImpl { public: LDVImpl(LiveDebugVariables *ps) : pass(*ps) {} - bool runOnMachineFunction(MachineFunction &mf); + bool runOnMachineFunction(MachineFunction &mf, bool InstrRef); /// Release all memory. void clear() { MF = nullptr; - StashedInstrReferences.clear(); + PHIValToPos.clear(); + RegToPHIIdx.clear(); + StashedDebugInstrs.clear(); userValues.clear(); userLabels.clear(); virtRegToEqClass.clear(); @@ -489,6 +660,10 @@ public: /// Map virtual register to an equivalence class. void mapVirtReg(Register VirtReg, UserValue *EC); + /// Replace any PHI referring to OldReg with its corresponding NewReg, if + /// present. + void splitPHIRegister(Register OldReg, ArrayRef<Register> NewRegs); + /// Replace all references to OldReg with NewRegs. void splitRegister(Register OldReg, ArrayRef<Register> NewRegs); @@ -555,11 +730,13 @@ void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) { for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) { OS << " [" << I.start() << ';' << I.stop() << "):"; if (I.value().isUndef()) - OS << "undef"; + OS << " undef"; else { - OS << I.value().getLocNo(); + I.value().printLocNos(OS); if (I.value().getWasIndirect()) OS << " ind"; + else if (I.value().getWasList()) + OS << " list"; } } for (unsigned i = 0, e = locations.size(); i != e; ++i) { @@ -623,11 +800,21 @@ UserValue *LDVImpl::lookupVirtReg(Register VirtReg) { } bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) { - // DBG_VALUE loc, offset, variable - if (MI.getNumOperands() != 4 || - !(MI.getDebugOffset().isReg() || MI.getDebugOffset().isImm()) || - !MI.getDebugVariableOp().isMetadata()) { - LLVM_DEBUG(dbgs() << "Can't handle " << MI); + // DBG_VALUE loc, offset, variable, expr + // DBG_VALUE_LIST variable, expr, locs... + if (!MI.isDebugValue()) { + LLVM_DEBUG(dbgs() << "Can't handle non-DBG_VALUE*: " << MI); + return false; + } + if (!MI.getDebugVariableOp().isMetadata()) { + LLVM_DEBUG(dbgs() << "Can't handle DBG_VALUE* with invalid variable: " + << MI); + return false; + } + if (MI.isNonListDebugValue() && + (MI.getNumOperands() != 4 || + !(MI.getDebugOffset().isImm() || MI.getDebugOffset().isReg()))) { + LLVM_DEBUG(dbgs() << "Can't handle malformed DBG_VALUE: " << MI); return false; } @@ -639,27 +826,28 @@ bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) { // (and if the machine verifier is improved to catch this), then these checks // could be removed or replaced by asserts. bool Discard = false; - if (MI.getDebugOperand(0).isReg() && - Register::isVirtualRegister(MI.getDebugOperand(0).getReg())) { - const Register Reg = MI.getDebugOperand(0).getReg(); - if (!LIS->hasInterval(Reg)) { - // The DBG_VALUE is described by a virtual register that does not have a - // live interval. Discard the DBG_VALUE. - Discard = true; - LLVM_DEBUG(dbgs() << "Discarding debug info (no LIS interval): " << Idx - << " " << MI); - } else { - // The DBG_VALUE is only valid if either Reg is live out from Idx, or Reg - // is defined dead at Idx (where Idx is the slot index for the instruction - // preceding the DBG_VALUE). - const LiveInterval &LI = LIS->getInterval(Reg); - LiveQueryResult LRQ = LI.Query(Idx); - if (!LRQ.valueOutOrDead()) { - // We have found a DBG_VALUE with the value in a virtual register that - // is not live. Discard the DBG_VALUE. + for (const MachineOperand &Op : MI.debug_operands()) { + if (Op.isReg() && Register::isVirtualRegister(Op.getReg())) { + const Register Reg = Op.getReg(); + if (!LIS->hasInterval(Reg)) { + // The DBG_VALUE is described by a virtual register that does not have a + // live interval. Discard the DBG_VALUE. Discard = true; - LLVM_DEBUG(dbgs() << "Discarding debug info (reg not live): " << Idx + LLVM_DEBUG(dbgs() << "Discarding debug info (no LIS interval): " << Idx << " " << MI); + } else { + // The DBG_VALUE is only valid if either Reg is live out from Idx, or + // Reg is defined dead at Idx (where Idx is the slot index for the + // instruction preceding the DBG_VALUE). + const LiveInterval &LI = LIS->getInterval(Reg); + LiveQueryResult LRQ = LI.Query(Idx); + if (!LRQ.valueOutOrDead()) { + // We have found a DBG_VALUE with the value in a virtual register that + // is not live. Discard the DBG_VALUE. + Discard = true; + LLVM_DEBUG(dbgs() << "Discarding debug info (reg not live): " << Idx + << " " << MI); + } } } } @@ -669,30 +857,42 @@ bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) { if (IsIndirect) assert(MI.getDebugOffset().getImm() == 0 && "DBG_VALUE with nonzero offset"); + bool IsList = MI.isDebugValueList(); const DILocalVariable *Var = MI.getDebugVariable(); const DIExpression *Expr = MI.getDebugExpression(); UserValue *UV = getUserValue(Var, Expr->getFragmentInfo(), MI.getDebugLoc()); if (!Discard) - UV->addDef(Idx, MI.getDebugOperand(0), IsIndirect, *Expr); + UV->addDef(Idx, + ArrayRef<MachineOperand>(MI.debug_operands().begin(), + MI.debug_operands().end()), + IsIndirect, IsList, *Expr); else { MachineOperand MO = MachineOperand::CreateReg(0U, false); MO.setIsDebug(); - UV->addDef(Idx, MO, false, *Expr); + // We should still pass a list the same size as MI.debug_operands() even if + // all MOs are undef, so that DbgVariableValue can correctly adjust the + // expression while removing the duplicated undefs. + SmallVector<MachineOperand, 4> UndefMOs(MI.getNumDebugOperands(), MO); + UV->addDef(Idx, UndefMOs, false, IsList, *Expr); } return true; } -bool LDVImpl::handleDebugInstrRef(MachineInstr &MI, SlotIndex Idx) { - assert(MI.isDebugRef()); - unsigned InstrNum = MI.getOperand(0).getImm(); - unsigned OperandNum = MI.getOperand(1).getImm(); - auto *Var = MI.getDebugVariable(); - auto *Expr = MI.getDebugExpression(); - auto &DL = MI.getDebugLoc(); - StashedInstrRef Stashed = - std::make_tuple(InstrNum, OperandNum, Var, Expr, DL); - StashedInstrReferences[Idx].push_back(Stashed); - return true; +MachineBasicBlock::iterator LDVImpl::handleDebugInstr(MachineInstr &MI, + SlotIndex Idx) { + assert(MI.isDebugValue() || MI.isDebugRef() || MI.isDebugPHI()); + + // In instruction referencing mode, there should be no DBG_VALUE instructions + // that refer to virtual registers. They might still refer to constants. + if (MI.isDebugValue()) + assert(!MI.getOperand(0).isReg() || !MI.getOperand(0).getReg().isVirtual()); + + // Unlink the instruction, store it in the debug instructions collection. + auto NextInst = std::next(MI.getIterator()); + auto *MBB = MI.getParent(); + MI.removeFromParent(); + StashedDebugInstrs.push_back({&MI, Idx, MBB}); + return NextInst; } bool LDVImpl::handleDebugLabel(MachineInstr &MI, SlotIndex Idx) { @@ -718,62 +918,71 @@ bool LDVImpl::handleDebugLabel(MachineInstr &MI, SlotIndex Idx) { return true; } -bool LDVImpl::collectDebugValues(MachineFunction &mf) { +bool LDVImpl::collectDebugValues(MachineFunction &mf, bool InstrRef) { bool Changed = false; - for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE; - ++MFI) { - MachineBasicBlock *MBB = &*MFI; - for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end(); + for (MachineBasicBlock &MBB : mf) { + for (MachineBasicBlock::iterator MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE;) { // Use the first debug instruction in the sequence to get a SlotIndex // for following consecutive debug instructions. - if (!MBBI->isDebugInstr()) { + if (!MBBI->isDebugOrPseudoInstr()) { ++MBBI; continue; } // Debug instructions has no slot index. Use the previous // non-debug instruction's SlotIndex as its SlotIndex. SlotIndex Idx = - MBBI == MBB->begin() - ? LIS->getMBBStartIdx(MBB) + MBBI == MBB.begin() + ? LIS->getMBBStartIdx(&MBB) : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot(); // Handle consecutive debug instructions with the same slot index. do { - // Only handle DBG_VALUE in handleDebugValue(). Skip all other - // kinds of debug instructions. - if ((MBBI->isDebugValue() && handleDebugValue(*MBBI, Idx)) || - (MBBI->isDebugRef() && handleDebugInstrRef(*MBBI, Idx)) || - (MBBI->isDebugLabel() && handleDebugLabel(*MBBI, Idx))) { - MBBI = MBB->erase(MBBI); + // In instruction referencing mode, pass each instr to handleDebugInstr + // to be unlinked. Ignore DBG_VALUE_LISTs -- they refer to vregs, and + // need to go through the normal live interval splitting process. + if (InstrRef && (MBBI->isNonListDebugValue() || MBBI->isDebugPHI() || + MBBI->isDebugRef())) { + MBBI = handleDebugInstr(*MBBI, Idx); + Changed = true; + // In normal debug mode, use the dedicated DBG_VALUE / DBG_LABEL handler + // to track things through register allocation, and erase the instr. + } else if ((MBBI->isDebugValue() && handleDebugValue(*MBBI, Idx)) || + (MBBI->isDebugLabel() && handleDebugLabel(*MBBI, Idx))) { + MBBI = MBB.erase(MBBI); Changed = true; } else ++MBBI; - } while (MBBI != MBBE && MBBI->isDebugInstr()); + } while (MBBI != MBBE && MBBI->isDebugOrPseudoInstr()); } } return Changed; } -void UserValue::extendDef(SlotIndex Idx, DbgVariableValue DbgValue, LiveRange *LR, - const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills, - LiveIntervals &LIS) { +void UserValue::extendDef( + SlotIndex Idx, DbgVariableValue DbgValue, + SmallDenseMap<unsigned, std::pair<LiveRange *, const VNInfo *>> + &LiveIntervalInfo, + Optional<std::pair<SlotIndex, SmallVector<unsigned>>> &Kills, + LiveIntervals &LIS) { SlotIndex Start = Idx; MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start); SlotIndex Stop = LIS.getMBBEndIdx(MBB); LocMap::iterator I = locInts.find(Start); - // Limit to VNI's live range. - bool ToEnd = true; - if (LR && VNI) { + // Limit to the intersection of the VNIs' live ranges. + for (auto &LII : LiveIntervalInfo) { + LiveRange *LR = LII.second.first; + assert(LR && LII.second.second && "Missing range info for Idx."); LiveInterval::Segment *Segment = LR->getSegmentContaining(Start); - if (!Segment || Segment->valno != VNI) { - if (Kills) - Kills->push_back(Start); - return; - } + assert(Segment && Segment->valno == LII.second.second && + "Invalid VNInfo for Idx given?"); if (Segment->end < Stop) { Stop = Segment->end; - ToEnd = false; + Kills = {Stop, {LII.first}}; + } else if (Segment->end == Stop && Kills.hasValue()) { + // If multiple locations end at the same place, track all of them in + // Kills. + Kills->second.push_back(LII.first); } } @@ -781,94 +990,116 @@ void UserValue::extendDef(SlotIndex Idx, DbgVariableValue DbgValue, LiveRange *L if (I.valid() && I.start() <= Start) { // Stop when meeting a different location or an already extended interval. Start = Start.getNextSlot(); - if (I.value() != DbgValue || I.stop() != Start) + if (I.value() != DbgValue || I.stop() != Start) { + // Clear `Kills`, as we have a new def available. + Kills = None; return; + } // This is a one-slot placeholder. Just skip it. ++I; } // Limited by the next def. - if (I.valid() && I.start() < Stop) + if (I.valid() && I.start() < Stop) { Stop = I.start(); - // Limited by VNI's live range. - else if (!ToEnd && Kills) - Kills->push_back(Stop); + // Clear `Kills`, as we have a new def available. + Kills = None; + } - if (Start < Stop) - I.insert(Start, Stop, DbgValue); + if (Start < Stop) { + DbgVariableValue ExtDbgValue(DbgValue); + I.insert(Start, Stop, std::move(ExtDbgValue)); + } } void UserValue::addDefsFromCopies( - LiveInterval *LI, DbgVariableValue DbgValue, - const SmallVectorImpl<SlotIndex> &Kills, + DbgVariableValue DbgValue, + SmallVectorImpl<std::pair<unsigned, LiveInterval *>> &LocIntervals, + SlotIndex KilledAt, SmallVectorImpl<std::pair<SlotIndex, DbgVariableValue>> &NewDefs, MachineRegisterInfo &MRI, LiveIntervals &LIS) { - if (Kills.empty()) - return; // Don't track copies from physregs, there are too many uses. - if (!Register::isVirtualRegister(LI->reg())) + if (any_of(LocIntervals, [](auto LocI) { + return !Register::isVirtualRegister(LocI.second->reg()); + })) return; // Collect all the (vreg, valno) pairs that are copies of LI. - SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues; - for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg())) { - MachineInstr *MI = MO.getParent(); - // Copies of the full value. - if (MO.getSubReg() || !MI->isCopy()) - continue; - Register DstReg = MI->getOperand(0).getReg(); + SmallDenseMap<unsigned, + SmallVector<std::pair<LiveInterval *, const VNInfo *>, 4>> + CopyValues; + for (auto &LocInterval : LocIntervals) { + unsigned LocNo = LocInterval.first; + LiveInterval *LI = LocInterval.second; + for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg())) { + MachineInstr *MI = MO.getParent(); + // Copies of the full value. + if (MO.getSubReg() || !MI->isCopy()) + continue; + Register DstReg = MI->getOperand(0).getReg(); - // Don't follow copies to physregs. These are usually setting up call - // arguments, and the argument registers are always call clobbered. We are - // better off in the source register which could be a callee-saved register, - // or it could be spilled. - if (!Register::isVirtualRegister(DstReg)) - continue; + // Don't follow copies to physregs. These are usually setting up call + // arguments, and the argument registers are always call clobbered. We are + // better off in the source register which could be a callee-saved + // register, or it could be spilled. + if (!Register::isVirtualRegister(DstReg)) + continue; - // Is the value extended to reach this copy? If not, another def may be - // blocking it, or we are looking at a wrong value of LI. - SlotIndex Idx = LIS.getInstructionIndex(*MI); - LocMap::iterator I = locInts.find(Idx.getRegSlot(true)); - if (!I.valid() || I.value() != DbgValue) - continue; + // Is the value extended to reach this copy? If not, another def may be + // blocking it, or we are looking at a wrong value of LI. + SlotIndex Idx = LIS.getInstructionIndex(*MI); + LocMap::iterator I = locInts.find(Idx.getRegSlot(true)); + if (!I.valid() || I.value() != DbgValue) + continue; - if (!LIS.hasInterval(DstReg)) - continue; - LiveInterval *DstLI = &LIS.getInterval(DstReg); - const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot()); - assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value"); - CopyValues.push_back(std::make_pair(DstLI, DstVNI)); + if (!LIS.hasInterval(DstReg)) + continue; + LiveInterval *DstLI = &LIS.getInterval(DstReg); + const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot()); + assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value"); + CopyValues[LocNo].push_back(std::make_pair(DstLI, DstVNI)); + } } if (CopyValues.empty()) return; - LLVM_DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI - << '\n'); +#if !defined(NDEBUG) + for (auto &LocInterval : LocIntervals) + LLVM_DEBUG(dbgs() << "Got " << CopyValues[LocInterval.first].size() + << " copies of " << *LocInterval.second << '\n'); +#endif - // Try to add defs of the copied values for each kill point. - for (unsigned i = 0, e = Kills.size(); i != e; ++i) { - SlotIndex Idx = Kills[i]; - for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) { - LiveInterval *DstLI = CopyValues[j].first; - const VNInfo *DstVNI = CopyValues[j].second; - if (DstLI->getVNInfoAt(Idx) != DstVNI) - continue; - // Check that there isn't already a def at Idx - LocMap::iterator I = locInts.find(Idx); - if (I.valid() && I.start() <= Idx) + // Try to add defs of the copied values for the kill point. Check that there + // isn't already a def at Idx. + LocMap::iterator I = locInts.find(KilledAt); + if (I.valid() && I.start() <= KilledAt) + return; + DbgVariableValue NewValue(DbgValue); + for (auto &LocInterval : LocIntervals) { + unsigned LocNo = LocInterval.first; + bool FoundCopy = false; + for (auto &LIAndVNI : CopyValues[LocNo]) { + LiveInterval *DstLI = LIAndVNI.first; + const VNInfo *DstVNI = LIAndVNI.second; + if (DstLI->getVNInfoAt(KilledAt) != DstVNI) continue; - LLVM_DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #" + LLVM_DEBUG(dbgs() << "Kill at " << KilledAt << " covered by valno #" << DstVNI->id << " in " << *DstLI << '\n'); MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def); assert(CopyMI && CopyMI->isCopy() && "Bad copy value"); - unsigned LocNo = getLocationNo(CopyMI->getOperand(0)); - DbgVariableValue NewValue = DbgValue.changeLocNo(LocNo); - I.insert(Idx, Idx.getNextSlot(), NewValue); - NewDefs.push_back(std::make_pair(Idx, NewValue)); + unsigned NewLocNo = getLocationNo(CopyMI->getOperand(0)); + NewValue = NewValue.changeLocNo(LocNo, NewLocNo); + FoundCopy = true; break; } + // If there are any killed locations we can't find a copy for, we can't + // extend the variable value. + if (!FoundCopy) + return; } + I.insert(KilledAt, KilledAt.getNextSlot(), NewValue); + NewDefs.push_back(std::make_pair(KilledAt, NewValue)); } void UserValue::computeIntervals(MachineRegisterInfo &MRI, @@ -885,34 +1116,54 @@ void UserValue::computeIntervals(MachineRegisterInfo &MRI, for (unsigned i = 0; i != Defs.size(); ++i) { SlotIndex Idx = Defs[i].first; DbgVariableValue DbgValue = Defs[i].second; - const MachineOperand &LocMO = locations[DbgValue.getLocNo()]; - - if (!LocMO.isReg()) { - extendDef(Idx, DbgValue, nullptr, nullptr, nullptr, LIS); - continue; - } - - // Register locations are constrained to where the register value is live. - if (Register::isVirtualRegister(LocMO.getReg())) { + SmallDenseMap<unsigned, std::pair<LiveRange *, const VNInfo *>> LIs; + SmallVector<const VNInfo *, 4> VNIs; + bool ShouldExtendDef = false; + for (unsigned LocNo : DbgValue.loc_nos()) { + const MachineOperand &LocMO = locations[LocNo]; + if (!LocMO.isReg() || !Register::isVirtualRegister(LocMO.getReg())) { + ShouldExtendDef |= !LocMO.isReg(); + continue; + } + ShouldExtendDef = true; LiveInterval *LI = nullptr; const VNInfo *VNI = nullptr; if (LIS.hasInterval(LocMO.getReg())) { LI = &LIS.getInterval(LocMO.getReg()); VNI = LI->getVNInfoAt(Idx); } - SmallVector<SlotIndex, 16> Kills; - extendDef(Idx, DbgValue, LI, VNI, &Kills, LIS); - // FIXME: Handle sub-registers in addDefsFromCopies. The problem is that - // if the original location for example is %vreg0:sub_hi, and we find a - // full register copy in addDefsFromCopies (at the moment it only handles - // full register copies), then we must add the sub1 sub-register index to - // the new location. However, that is only possible if the new virtual - // register is of the same regclass (or if there is an equivalent - // sub-register in that regclass). For now, simply skip handling copies if - // a sub-register is involved. - if (LI && !LocMO.getSubReg()) - addDefsFromCopies(LI, DbgValue, Kills, Defs, MRI, LIS); - continue; + if (LI && VNI) + LIs[LocNo] = {LI, VNI}; + } + if (ShouldExtendDef) { + Optional<std::pair<SlotIndex, SmallVector<unsigned>>> Kills; + extendDef(Idx, DbgValue, LIs, Kills, LIS); + + if (Kills) { + SmallVector<std::pair<unsigned, LiveInterval *>, 2> KilledLocIntervals; + bool AnySubreg = false; + for (unsigned LocNo : Kills->second) { + const MachineOperand &LocMO = this->locations[LocNo]; + if (LocMO.getSubReg()) { + AnySubreg = true; + break; + } + LiveInterval *LI = &LIS.getInterval(LocMO.getReg()); + KilledLocIntervals.push_back({LocNo, LI}); + } + + // FIXME: Handle sub-registers in addDefsFromCopies. The problem is that + // if the original location for example is %vreg0:sub_hi, and we find a + // full register copy in addDefsFromCopies (at the moment it only + // handles full register copies), then we must add the sub1 sub-register + // index to the new location. However, that is only possible if the new + // virtual register is of the same regclass (or if there is an + // equivalent sub-register in that regclass). For now, simply skip + // handling copies if a sub-register is involved. + if (!AnySubreg) + addDefsFromCopies(DbgValue, KilledLocIntervals, Kills->first, Defs, + MRI, LIS); + } } // For physregs, we only mark the start slot idx. DwarfDebug will see it @@ -927,7 +1178,11 @@ void UserValue::computeIntervals(MachineRegisterInfo &MRI, // location's lexical scope. In this case, splitting of an interval // can result in an interval outside of the scope being created, // causing extra unnecessary DBG_VALUEs to be emitted. To prevent - // this, trim the intervals to the lexical scope. + // this, trim the intervals to the lexical scope in the case of inlined + // variables, since heavy inlining may cause production of dramatically big + // number of DBG_VALUEs to be generated. + if (!dl.getInlinedAt()) + return; LexicalScope *Scope = LS.findLexicalScope(dl); if (!Scope) @@ -1007,7 +1262,7 @@ void LDVImpl::computeIntervals() { } } -bool LDVImpl::runOnMachineFunction(MachineFunction &mf) { +bool LDVImpl::runOnMachineFunction(MachineFunction &mf, bool InstrRef) { clear(); MF = &mf; LIS = &pass.getAnalysis<LiveIntervals>(); @@ -1015,9 +1270,24 @@ bool LDVImpl::runOnMachineFunction(MachineFunction &mf) { LLVM_DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: " << mf.getName() << " **********\n"); - bool Changed = collectDebugValues(mf); + bool Changed = collectDebugValues(mf, InstrRef); computeIntervals(); LLVM_DEBUG(print(dbgs())); + + // Collect the set of VReg / SlotIndexs where PHIs occur; index the sensitive + // VRegs too, for when we're notified of a range split. + SlotIndexes *Slots = LIS->getSlotIndexes(); + for (const auto &PHIIt : MF->DebugPHIPositions) { + const MachineFunction::DebugPHIRegallocPos &Position = PHIIt.second; + MachineBasicBlock *MBB = Position.MBB; + Register Reg = Position.Reg; + unsigned SubReg = Position.SubReg; + SlotIndex SI = Slots->getMBBStartIdx(MBB); + PHIValPos VP = {SI, Reg, SubReg}; + PHIValToPos.insert(std::make_pair(PHIIt.first, VP)); + RegToPHIIdx[Reg].push_back(PHIIt.first); + } + ModifiedMF = Changed; return Changed; } @@ -1041,9 +1311,19 @@ bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) { removeDebugInstrs(mf); return false; } + + // Have we been asked to track variable locations using instruction + // referencing? + bool InstrRef = false; + auto *TPC = getAnalysisIfAvailable<TargetPassConfig>(); + if (TPC) { + auto &TM = TPC->getTM<TargetMachine>(); + InstrRef = TM.Options.ValueTrackingVariableLocations; + } + if (!pImpl) pImpl = new LDVImpl(this); - return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf); + return static_cast<LDVImpl *>(pImpl)->runOnMachineFunction(mf, InstrRef); } void LiveDebugVariables::releaseMemory() { @@ -1091,7 +1371,7 @@ UserValue::splitLocation(unsigned OldLocNo, ArrayRef<Register> NewRegs, break; // Now LII->end > LocMapI.start(). Do we have an overlap? - if (LocMapI.value().getLocNo() == OldLocNo && + if (LocMapI.value().containsLocNo(OldLocNo) && LII->start < LocMapI.stop()) { // Overlapping correct location. Allocate NewLocNo now. if (NewLocNo == UndefLocNo) { @@ -1112,7 +1392,7 @@ UserValue::splitLocation(unsigned OldLocNo, ArrayRef<Register> NewRegs, LocMapI.setStopUnchecked(LII->end); // Change the value in the overlap. This may trigger coalescing. - LocMapI.setValue(OldDbgValue.changeLocNo(NewLocNo)); + LocMapI.setValue(OldDbgValue.changeLocNo(OldLocNo, NewLocNo)); // Re-insert any removed OldDbgValue ranges. if (LStart < LocMapI.start()) { @@ -1176,7 +1456,50 @@ UserValue::splitRegister(Register OldReg, ArrayRef<Register> NewRegs, return DidChange; } +void LDVImpl::splitPHIRegister(Register OldReg, ArrayRef<Register> NewRegs) { + auto RegIt = RegToPHIIdx.find(OldReg); + if (RegIt == RegToPHIIdx.end()) + return; + + std::vector<std::pair<Register, unsigned>> NewRegIdxes; + // Iterate over all the debug instruction numbers affected by this split. + for (unsigned InstrID : RegIt->second) { + auto PHIIt = PHIValToPos.find(InstrID); + assert(PHIIt != PHIValToPos.end()); + const SlotIndex &Slot = PHIIt->second.SI; + assert(OldReg == PHIIt->second.Reg); + + // Find the new register that covers this position. + for (auto NewReg : NewRegs) { + const LiveInterval &LI = LIS->getInterval(NewReg); + auto LII = LI.find(Slot); + if (LII != LI.end() && LII->start <= Slot) { + // This new register covers this PHI position, record this for indexing. + NewRegIdxes.push_back(std::make_pair(NewReg, InstrID)); + // Record that this value lives in a different VReg now. + PHIIt->second.Reg = NewReg; + break; + } + } + + // If we do not find a new register covering this PHI, then register + // allocation has dropped its location, for example because it's not live. + // The old VReg will not be mapped to a physreg, and the instruction + // number will have been optimized out. + } + + // Re-create register index using the new register numbers. + RegToPHIIdx.erase(RegIt); + for (auto &RegAndInstr : NewRegIdxes) + RegToPHIIdx[RegAndInstr.first].push_back(RegAndInstr.second); +} + void LDVImpl::splitRegister(Register OldReg, ArrayRef<Register> NewRegs) { + // Consider whether this split range affects any PHI locations. + splitPHIRegister(OldReg, NewRegs); + + // Check whether any intervals mapped by a DBG_VALUE were split and need + // updating. bool DidChange = false; for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext()) DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS); @@ -1269,21 +1592,15 @@ void UserValue::rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF, // DBG_VALUE intervals with different vregs that were allocated to the same // physical register. for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) { - DbgVariableValue DbgValue = I.value(); - // Undef values don't exist in locations (and thus not in LocNoMap either) - // so skip over them. See getLocationNo(). - if (DbgValue.isUndef()) - continue; - unsigned NewLocNo = LocNoMap[DbgValue.getLocNo()]; - I.setValueUnchecked(DbgValue.changeLocNo(NewLocNo)); + I.setValueUnchecked(I.value().remapLocNos(LocNoMap)); I.setStart(I.start()); } } /// Find an iterator for inserting a DBG_VALUE instruction. static MachineBasicBlock::iterator -findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, - LiveIntervals &LIS) { +findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, LiveIntervals &LIS, + BlockSkipInstsMap &BBSkipInstsMap) { SlotIndex Start = LIS.getMBBStartIdx(MBB); Idx = Idx.getBaseIndex(); @@ -1292,7 +1609,29 @@ findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, while (!(MI = LIS.getInstructionFromIndex(Idx))) { // We've reached the beginning of MBB. if (Idx == Start) { - MachineBasicBlock::iterator I = MBB->SkipPHIsLabelsAndDebug(MBB->begin()); + // Retrieve the last PHI/Label/Debug location found when calling + // SkipPHIsLabelsAndDebug last time. Start searching from there. + // + // Note the iterator kept in BBSkipInstsMap is one step back based + // on the iterator returned by SkipPHIsLabelsAndDebug last time. + // One exception is when SkipPHIsLabelsAndDebug returns MBB->begin(), + // BBSkipInstsMap won't save it. This is to consider the case that + // new instructions may be inserted at the beginning of MBB after + // last call of SkipPHIsLabelsAndDebug. If we save MBB->begin() in + // BBSkipInstsMap, after new non-phi/non-label/non-debug instructions + // are inserted at the beginning of the MBB, the iterator in + // BBSkipInstsMap won't point to the beginning of the MBB anymore. + // Therefore The next search in SkipPHIsLabelsAndDebug will skip those + // newly added instructions and that is unwanted. + MachineBasicBlock::iterator BeginIt; + auto MapIt = BBSkipInstsMap.find(MBB); + if (MapIt == BBSkipInstsMap.end()) + BeginIt = MBB->begin(); + else + BeginIt = std::next(MapIt->second); + auto I = MBB->SkipPHIsLabelsAndDebug(BeginIt); + if (I != BeginIt) + BBSkipInstsMap[MBB] = std::prev(I); return I; } Idx = Idx.getPrevIndex(); @@ -1306,21 +1645,24 @@ findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, /// Find an iterator for inserting the next DBG_VALUE instruction /// (or end if no more insert locations found). static MachineBasicBlock::iterator -findNextInsertLocation(MachineBasicBlock *MBB, - MachineBasicBlock::iterator I, - SlotIndex StopIdx, MachineOperand &LocMO, - LiveIntervals &LIS, - const TargetRegisterInfo &TRI) { - if (!LocMO.isReg()) +findNextInsertLocation(MachineBasicBlock *MBB, MachineBasicBlock::iterator I, + SlotIndex StopIdx, ArrayRef<MachineOperand> LocMOs, + LiveIntervals &LIS, const TargetRegisterInfo &TRI) { + SmallVector<Register, 4> Regs; + for (const MachineOperand &LocMO : LocMOs) + if (LocMO.isReg()) + Regs.push_back(LocMO.getReg()); + if (Regs.empty()) return MBB->instr_end(); - Register Reg = LocMO.getReg(); // Find the next instruction in the MBB that define the register Reg. while (I != MBB->end() && !I->isTerminator()) { if (!LIS.isNotInMIMap(*I) && SlotIndex::isEarlierEqualInstr(StopIdx, LIS.getInstructionIndex(*I))) break; - if (I->definesRegister(Reg, &TRI)) + if (any_of(Regs, [&I, &TRI](Register &Reg) { + return I->definesRegister(Reg, &TRI); + })) // The insert location is directly after the instruction/bundle. return std::next(I); ++I; @@ -1330,23 +1672,30 @@ findNextInsertLocation(MachineBasicBlock *MBB, void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx, SlotIndex StopIdx, DbgVariableValue DbgValue, - bool Spilled, unsigned SpillOffset, + ArrayRef<bool> LocSpills, + ArrayRef<unsigned> SpillOffsets, LiveIntervals &LIS, const TargetInstrInfo &TII, - const TargetRegisterInfo &TRI) { + const TargetRegisterInfo &TRI, + BlockSkipInstsMap &BBSkipInstsMap) { SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB); // Only search within the current MBB. StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx; - MachineBasicBlock::iterator I = findInsertLocation(MBB, StartIdx, LIS); + MachineBasicBlock::iterator I = + findInsertLocation(MBB, StartIdx, LIS, BBSkipInstsMap); // Undef values don't exist in locations so create new "noreg" register MOs // for them. See getLocationNo(). - MachineOperand MO = - !DbgValue.isUndef() - ? locations[DbgValue.getLocNo()] - : MachineOperand::CreateReg( - /* Reg */ 0, /* isDef */ false, /* isImp */ false, - /* isKill */ false, /* isDead */ false, - /* isUndef */ false, /* isEarlyClobber */ false, - /* SubReg */ 0, /* isDebug */ true); + SmallVector<MachineOperand, 8> MOs; + if (DbgValue.isUndef()) { + MOs.assign(DbgValue.loc_nos().size(), + MachineOperand::CreateReg( + /* Reg */ 0, /* isDef */ false, /* isImp */ false, + /* isKill */ false, /* isDead */ false, + /* isUndef */ false, /* isEarlyClobber */ false, + /* SubReg */ 0, /* isDebug */ true)); + } else { + for (unsigned LocNo : DbgValue.loc_nos()) + MOs.push_back(locations[LocNo]); + } ++NumInsertedDebugValues; @@ -1359,32 +1708,45 @@ void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx, // that the original virtual register was a pointer. Also, add the stack slot // offset for the spilled register to the expression. const DIExpression *Expr = DbgValue.getExpression(); - uint8_t DIExprFlags = DIExpression::ApplyOffset; bool IsIndirect = DbgValue.getWasIndirect(); - if (Spilled) { - if (IsIndirect) - DIExprFlags |= DIExpression::DerefAfter; - Expr = - DIExpression::prepend(Expr, DIExprFlags, SpillOffset); - IsIndirect = true; - } + bool IsList = DbgValue.getWasList(); + for (unsigned I = 0, E = LocSpills.size(); I != E; ++I) { + if (LocSpills[I]) { + if (!IsList) { + uint8_t DIExprFlags = DIExpression::ApplyOffset; + if (IsIndirect) + DIExprFlags |= DIExpression::DerefAfter; + Expr = DIExpression::prepend(Expr, DIExprFlags, SpillOffsets[I]); + IsIndirect = true; + } else { + SmallVector<uint64_t, 4> Ops; + DIExpression::appendOffset(Ops, SpillOffsets[I]); + Ops.push_back(dwarf::DW_OP_deref); + Expr = DIExpression::appendOpsToArg(Expr, Ops, I); + } + } - assert((!Spilled || MO.isFI()) && "a spilled location must be a frame index"); + assert((!LocSpills[I] || MOs[I].isFI()) && + "a spilled location must be a frame index"); + } + unsigned DbgValueOpcode = + IsList ? TargetOpcode::DBG_VALUE_LIST : TargetOpcode::DBG_VALUE; do { - BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE), - IsIndirect, MO, Variable, Expr); + BuildMI(*MBB, I, getDebugLoc(), TII.get(DbgValueOpcode), IsIndirect, MOs, + Variable, Expr); - // Continue and insert DBG_VALUES after every redefinition of register + // Continue and insert DBG_VALUES after every redefinition of a register // associated with the debug value within the range - I = findNextInsertLocation(MBB, I, StopIdx, MO, LIS, TRI); + I = findNextInsertLocation(MBB, I, StopIdx, MOs, LIS, TRI); } while (I != MBB->end()); } void UserLabel::insertDebugLabel(MachineBasicBlock *MBB, SlotIndex Idx, - LiveIntervals &LIS, - const TargetInstrInfo &TII) { - MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS); + LiveIntervals &LIS, const TargetInstrInfo &TII, + BlockSkipInstsMap &BBSkipInstsMap) { + MachineBasicBlock::iterator I = + findInsertLocation(MBB, Idx, LIS, BBSkipInstsMap); ++NumInsertedDebugLabels; BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_LABEL)) .addMetadata(Label); @@ -1393,17 +1755,24 @@ void UserLabel::insertDebugLabel(MachineBasicBlock *MBB, SlotIndex Idx, void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, const TargetInstrInfo &TII, const TargetRegisterInfo &TRI, - const SpillOffsetMap &SpillOffsets) { + const SpillOffsetMap &SpillOffsets, + BlockSkipInstsMap &BBSkipInstsMap) { MachineFunction::iterator MFEnd = VRM->getMachineFunction().end(); for (LocMap::const_iterator I = locInts.begin(); I.valid();) { SlotIndex Start = I.start(); SlotIndex Stop = I.stop(); DbgVariableValue DbgValue = I.value(); - auto SpillIt = !DbgValue.isUndef() ? SpillOffsets.find(DbgValue.getLocNo()) - : SpillOffsets.end(); - bool Spilled = SpillIt != SpillOffsets.end(); - unsigned SpillOffset = Spilled ? SpillIt->second : 0; + + SmallVector<bool> SpilledLocs; + SmallVector<unsigned> LocSpillOffsets; + for (unsigned LocNo : DbgValue.loc_nos()) { + auto SpillIt = + !DbgValue.isUndef() ? SpillOffsets.find(LocNo) : SpillOffsets.end(); + bool Spilled = SpillIt != SpillOffsets.end(); + SpilledLocs.push_back(Spilled); + LocSpillOffsets.push_back(Spilled ? SpillIt->second : 0); + } // If the interval start was trimmed to the lexical scope insert the // DBG_VALUE at the previous index (otherwise it appears after the @@ -1411,14 +1780,14 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, if (trimmedDefs.count(Start)) Start = Start.getPrevIndex(); - LLVM_DEBUG(dbgs() << "\t[" << Start << ';' << Stop - << "):" << DbgValue.getLocNo()); + LLVM_DEBUG(auto &dbg = dbgs(); dbg << "\t[" << Start << ';' << Stop << "):"; + DbgValue.printLocNos(dbg)); MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator(); SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB); LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd); - insertDebugValue(&*MBB, Start, Stop, DbgValue, Spilled, SpillOffset, LIS, - TII, TRI); + insertDebugValue(&*MBB, Start, Stop, DbgValue, SpilledLocs, LocSpillOffsets, + LIS, TII, TRI, BBSkipInstsMap); // This interval may span multiple basic blocks. // Insert a DBG_VALUE into each one. while (Stop > MBBEnd) { @@ -1428,8 +1797,8 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, break; MBBEnd = LIS.getMBBEndIdx(&*MBB); LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd); - insertDebugValue(&*MBB, Start, Stop, DbgValue, Spilled, SpillOffset, LIS, - TII, TRI); + insertDebugValue(&*MBB, Start, Stop, DbgValue, SpilledLocs, + LocSpillOffsets, LIS, TII, TRI, BBSkipInstsMap); } LLVM_DEBUG(dbgs() << '\n'); if (MBB == MFEnd) @@ -1439,12 +1808,13 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, } } -void UserLabel::emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII) { +void UserLabel::emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII, + BlockSkipInstsMap &BBSkipInstsMap) { LLVM_DEBUG(dbgs() << "\t" << loc); MachineFunction::iterator MBB = LIS.getMBBFromIndex(loc)->getIterator(); LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB)); - insertDebugLabel(&*MBB, loc, LIS, TII); + insertDebugLabel(&*MBB, loc, LIS, TII, BBSkipInstsMap); LLVM_DEBUG(dbgs() << '\n'); } @@ -1453,41 +1823,111 @@ void LDVImpl::emitDebugValues(VirtRegMap *VRM) { LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"); if (!MF) return; + + BlockSkipInstsMap BBSkipInstsMap; const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo(); SpillOffsetMap SpillOffsets; for (auto &userValue : userValues) { LLVM_DEBUG(userValue->print(dbgs(), TRI)); userValue->rewriteLocations(*VRM, *MF, *TII, *TRI, SpillOffsets); - userValue->emitDebugValues(VRM, *LIS, *TII, *TRI, SpillOffsets); + userValue->emitDebugValues(VRM, *LIS, *TII, *TRI, SpillOffsets, + BBSkipInstsMap); } LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG LABELS **********\n"); for (auto &userLabel : userLabels) { LLVM_DEBUG(userLabel->print(dbgs(), TRI)); - userLabel->emitDebugLabel(*LIS, *TII); + userLabel->emitDebugLabel(*LIS, *TII, BBSkipInstsMap); } - LLVM_DEBUG(dbgs() << "********** EMITTING INSTR REFERENCES **********\n"); + LLVM_DEBUG(dbgs() << "********** EMITTING DEBUG PHIS **********\n"); - // Re-insert any DBG_INSTR_REFs back in the position they were. Ordering - // is preserved by vector. auto Slots = LIS->getSlotIndexes(); - const MCInstrDesc &RefII = TII->get(TargetOpcode::DBG_INSTR_REF); - for (auto &P : StashedInstrReferences) { - const SlotIndex &Idx = P.first; - auto *MBB = Slots->getMBBFromIndex(Idx); - MachineBasicBlock::iterator insertPos = findInsertLocation(MBB, Idx, *LIS); - for (auto &Stashed : P.second) { - auto MIB = BuildMI(*MF, std::get<4>(Stashed), RefII); - MIB.addImm(std::get<0>(Stashed)); - MIB.addImm(std::get<1>(Stashed)); - MIB.addMetadata(std::get<2>(Stashed)); - MIB.addMetadata(std::get<3>(Stashed)); - MachineInstr *New = MIB; - MBB->insert(insertPos, New); + for (auto &It : PHIValToPos) { + // For each ex-PHI, identify its physreg location or stack slot, and emit + // a DBG_PHI for it. + unsigned InstNum = It.first; + auto Slot = It.second.SI; + Register Reg = It.second.Reg; + unsigned SubReg = It.second.SubReg; + + MachineBasicBlock *OrigMBB = Slots->getMBBFromIndex(Slot); + if (VRM->isAssignedReg(Reg) && + Register::isPhysicalRegister(VRM->getPhys(Reg))) { + unsigned PhysReg = VRM->getPhys(Reg); + if (SubReg != 0) + PhysReg = TRI->getSubReg(PhysReg, SubReg); + + auto Builder = BuildMI(*OrigMBB, OrigMBB->begin(), DebugLoc(), + TII->get(TargetOpcode::DBG_PHI)); + Builder.addReg(PhysReg); + Builder.addImm(InstNum); + } else if (VRM->getStackSlot(Reg) != VirtRegMap::NO_STACK_SLOT) { + const MachineRegisterInfo &MRI = MF->getRegInfo(); + const TargetRegisterClass *TRC = MRI.getRegClass(Reg); + unsigned SpillSize, SpillOffset; + + // Test whether this location is legal with the given subreg. + bool Success = + TII->getStackSlotRange(TRC, SubReg, SpillSize, SpillOffset, *MF); + + if (Success) { + auto Builder = BuildMI(*OrigMBB, OrigMBB->begin(), DebugLoc(), + TII->get(TargetOpcode::DBG_PHI)); + Builder.addFrameIndex(VRM->getStackSlot(Reg)); + Builder.addImm(InstNum); + } + } + // If there was no mapping for a value ID, it's optimized out. Create no + // DBG_PHI, and any variables using this value will become optimized out. + } + MF->DebugPHIPositions.clear(); + + LLVM_DEBUG(dbgs() << "********** EMITTING INSTR REFERENCES **********\n"); + + // Re-insert any debug instrs back in the position they were. Ordering + // is preserved by vector. We must re-insert in the same order to ensure that + // debug instructions don't swap, which could re-order assignments. + for (auto &P : StashedDebugInstrs) { + SlotIndex Idx = P.Idx; + + // Start block index: find the first non-debug instr in the block, and + // insert before it. + if (Idx == Slots->getMBBStartIdx(P.MBB)) { + MachineBasicBlock::iterator InsertPos = + findInsertLocation(P.MBB, Idx, *LIS, BBSkipInstsMap); + P.MBB->insert(InsertPos, P.MI); + continue; + } + + if (MachineInstr *Pos = Slots->getInstructionFromIndex(Idx)) { + // Insert at the end of any debug instructions. + auto PostDebug = std::next(Pos->getIterator()); + PostDebug = skipDebugInstructionsForward(PostDebug, P.MBB->instr_end()); + P.MBB->insert(PostDebug, P.MI); + } else { + // Insert position disappeared; walk forwards through slots until we + // find a new one. + SlotIndex End = Slots->getMBBEndIdx(P.MBB); + for (; Idx < End; Idx = Slots->getNextNonNullIndex(Idx)) { + Pos = Slots->getInstructionFromIndex(Idx); + if (Pos) { + P.MBB->insert(Pos->getIterator(), P.MI); + break; + } + } + + // We have reached the end of the block and didn't find anywhere to + // insert! It's not safe to discard any debug instructions; place them + // in front of the first terminator, or in front of end(). + if (Idx >= End) { + auto TermIt = P.MBB->getFirstTerminator(); + P.MBB->insert(TermIt, P.MI); + } } } EmitDone = true; + BBSkipInstsMap.clear(); } void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) { |