| //===- LiveDebugVariables.cpp - Tracking debug info variables -------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the LiveDebugVariables analysis. |
| // |
| // Remove all DBG_VALUE instructions referencing virtual registers and replace |
| // them with a data structure tracking where live user variables are kept - in a |
| // virtual register or in a stack slot. |
| // |
| // Allow the data structure to be updated during register allocation when values |
| // are moved between registers and stack slots. Finally emit new DBG_VALUE |
| // instructions after register allocation is complete. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LiveDebugVariables.h" |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/IntervalMap.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallSet.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/CodeGen/LexicalScopes.h" |
| #include "llvm/CodeGen/LiveInterval.h" |
| #include "llvm/CodeGen/LiveIntervals.h" |
| #include "llvm/CodeGen/MachineBasicBlock.h" |
| #include "llvm/CodeGen/MachineDominators.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineInstr.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineOperand.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/CodeGen/SlotIndexes.h" |
| #include "llvm/CodeGen/TargetInstrInfo.h" |
| #include "llvm/CodeGen/TargetOpcodes.h" |
| #include "llvm/CodeGen/TargetRegisterInfo.h" |
| #include "llvm/CodeGen/TargetSubtargetInfo.h" |
| #include "llvm/CodeGen/VirtRegMap.h" |
| #include "llvm/Config/llvm-config.h" |
| #include "llvm/IR/DebugInfoMetadata.h" |
| #include "llvm/IR/DebugLoc.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/Metadata.h" |
| #include "llvm/MC/MCRegisterInfo.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <iterator> |
| #include <memory> |
| #include <utility> |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "livedebugvars" |
| |
| static cl::opt<bool> |
| EnableLDV("live-debug-variables", cl::init(true), |
| cl::desc("Enable the live debug variables pass"), cl::Hidden); |
| |
| STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted"); |
| STATISTIC(NumInsertedDebugLabels, "Number of DBG_LABELs inserted"); |
| |
| char LiveDebugVariables::ID = 0; |
| |
| INITIALIZE_PASS_BEGIN(LiveDebugVariables, DEBUG_TYPE, |
| "Debug Variable Analysis", false, false) |
| INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) |
| INITIALIZE_PASS_DEPENDENCY(LiveIntervals) |
| INITIALIZE_PASS_END(LiveDebugVariables, DEBUG_TYPE, |
| "Debug Variable Analysis", false, false) |
| |
| void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.addRequired<MachineDominatorTree>(); |
| AU.addRequiredTransitive<LiveIntervals>(); |
| AU.setPreservesAll(); |
| MachineFunctionPass::getAnalysisUsage(AU); |
| } |
| |
| LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID) { |
| initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| enum : unsigned { UndefLocNo = ~0U }; |
| |
| /// Describes a location by number along with some flags about the original |
| /// usage of the location. |
| class DbgValueLocation { |
| public: |
| DbgValueLocation(unsigned LocNo, bool WasIndirect) |
| : LocNo(LocNo), WasIndirect(WasIndirect) { |
| static_assert(sizeof(*this) == sizeof(unsigned), "bad bitfield packing"); |
| assert(locNo() == LocNo && "location truncation"); |
| } |
| |
| DbgValueLocation() : LocNo(0), WasIndirect(0) {} |
| |
| unsigned locNo() const { |
| // Fix up the undef location number, which gets truncated. |
| return LocNo == INT_MAX ? UndefLocNo : LocNo; |
| } |
| bool wasIndirect() const { return WasIndirect; } |
| bool isUndef() const { return locNo() == UndefLocNo; } |
| |
| DbgValueLocation changeLocNo(unsigned NewLocNo) const { |
| return DbgValueLocation(NewLocNo, WasIndirect); |
| } |
| |
| friend inline bool operator==(const DbgValueLocation &LHS, |
| const DbgValueLocation &RHS) { |
| return LHS.LocNo == RHS.LocNo && LHS.WasIndirect == RHS.WasIndirect; |
| } |
| |
| friend inline bool operator!=(const DbgValueLocation &LHS, |
| const DbgValueLocation &RHS) { |
| return !(LHS == RHS); |
| } |
| |
| private: |
| unsigned LocNo : 31; |
| unsigned WasIndirect : 1; |
| }; |
| |
| /// Map of where a user value is live, and its location. |
| using LocMap = IntervalMap<SlotIndex, DbgValueLocation, 4>; |
| |
| /// Map of stack slot offsets for spilled locations. |
| /// Non-spilled locations are not added to the map. |
| using SpillOffsetMap = DenseMap<unsigned, unsigned>; |
| |
| namespace { |
| |
| class LDVImpl; |
| |
| /// A user value is a part of a debug info user variable. |
| /// |
| /// A DBG_VALUE instruction notes that (a sub-register of) a virtual register |
| /// holds part of a user variable. The part is identified by a byte offset. |
| /// |
| /// UserValues are grouped into equivalence classes for easier searching. Two |
| /// user values are related if they refer to the same variable, or if they are |
| /// held by the same virtual register. The equivalence class is the transitive |
| /// closure of that relation. |
| class UserValue { |
| const DILocalVariable *Variable; ///< The debug info variable we are part of. |
| const DIExpression *Expression; ///< Any complex address expression. |
| DebugLoc dl; ///< The debug location for the variable. This is |
| ///< used by dwarf writer to find lexical scope. |
| UserValue *leader; ///< Equivalence class leader. |
| UserValue *next = nullptr; ///< Next value in equivalence class, or null. |
| |
| /// Numbered locations referenced by locmap. |
| SmallVector<MachineOperand, 4> locations; |
| |
| /// Map of slot indices where this value is live. |
| LocMap locInts; |
| |
| /// Set of interval start indexes that have been trimmed to the |
| /// lexical scope. |
| SmallSet<SlotIndex, 2> trimmedDefs; |
| |
| /// Insert a DBG_VALUE into MBB at Idx for LocNo. |
| void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx, |
| SlotIndex StopIdx, DbgValueLocation Loc, bool Spilled, |
| unsigned SpillOffset, LiveIntervals &LIS, |
| const TargetInstrInfo &TII, |
| const TargetRegisterInfo &TRI); |
| |
| /// Replace OldLocNo ranges with NewRegs ranges where NewRegs |
| /// is live. Returns true if any changes were made. |
| bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs, |
| LiveIntervals &LIS); |
| |
| public: |
| /// Create a new UserValue. |
| UserValue(const DILocalVariable *var, const DIExpression *expr, DebugLoc L, |
| LocMap::Allocator &alloc) |
| : Variable(var), Expression(expr), dl(std::move(L)), leader(this), |
| locInts(alloc) {} |
| |
| /// Get the leader of this value's equivalence class. |
| UserValue *getLeader() { |
| UserValue *l = leader; |
| while (l != l->leader) |
| l = l->leader; |
| return leader = l; |
| } |
| |
| /// Return the next UserValue in the equivalence class. |
| UserValue *getNext() const { return next; } |
| |
| /// Does this UserValue match the parameters? |
| bool match(const DILocalVariable *Var, const DIExpression *Expr, |
| const DILocation *IA) const { |
| // FIXME: The fragment should be part of the equivalence class, but not |
| // other things in the expression like stack values. |
| return Var == Variable && Expr == Expression && dl->getInlinedAt() == IA; |
| } |
| |
| /// Merge equivalence classes. |
| static UserValue *merge(UserValue *L1, UserValue *L2) { |
| L2 = L2->getLeader(); |
| if (!L1) |
| return L2; |
| L1 = L1->getLeader(); |
| if (L1 == L2) |
| return L1; |
| // Splice L2 before L1's members. |
| UserValue *End = L2; |
| while (End->next) { |
| End->leader = L1; |
| End = End->next; |
| } |
| End->leader = L1; |
| End->next = L1->next; |
| L1->next = L2; |
| return L1; |
| } |
| |
| /// Return the location number that matches Loc. |
| /// |
| /// For undef values we always return location number UndefLocNo without |
| /// inserting anything in locations. Since locations is a vector and the |
| /// location number is the position in the vector and UndefLocNo is ~0, |
| /// we would need a very big vector to put the value at the right position. |
| unsigned getLocationNo(const MachineOperand &LocMO) { |
| if (LocMO.isReg()) { |
| if (LocMO.getReg() == 0) |
| return UndefLocNo; |
| // For register locations we dont care about use/def and other flags. |
| for (unsigned i = 0, e = locations.size(); i != e; ++i) |
| if (locations[i].isReg() && |
| locations[i].getReg() == LocMO.getReg() && |
| locations[i].getSubReg() == LocMO.getSubReg()) |
| return i; |
| } else |
| for (unsigned i = 0, e = locations.size(); i != e; ++i) |
| if (LocMO.isIdenticalTo(locations[i])) |
| return i; |
| locations.push_back(LocMO); |
| // We are storing a MachineOperand outside a MachineInstr. |
| locations.back().clearParent(); |
| // Don't store def operands. |
| if (locations.back().isReg()) { |
| if (locations.back().isDef()) |
| locations.back().setIsDead(false); |
| locations.back().setIsUse(); |
| } |
| return locations.size() - 1; |
| } |
| |
| /// Ensure that all virtual register locations are mapped. |
| void mapVirtRegs(LDVImpl *LDV); |
| |
| /// Add a definition point to this value. |
| void addDef(SlotIndex Idx, const MachineOperand &LocMO, bool IsIndirect) { |
| DbgValueLocation Loc(getLocationNo(LocMO), IsIndirect); |
| // Add a singular (Idx,Idx) -> Loc mapping. |
| LocMap::iterator I = locInts.find(Idx); |
| if (!I.valid() || I.start() != Idx) |
| I.insert(Idx, Idx.getNextSlot(), Loc); |
| else |
| // A later DBG_VALUE at the same SlotIndex overrides the old location. |
| I.setValue(Loc); |
| } |
| |
| /// Extend the current definition as far as possible down. |
| /// |
| /// Stop when meeting an existing def or when leaving the live |
| /// range of VNI. End points where VNI is no longer live are added to Kills. |
| /// |
| /// We only propagate DBG_VALUES locally here. LiveDebugValues performs a |
| /// data-flow analysis to propagate them beyond basic block boundaries. |
| /// |
| /// \param Idx Starting point for the definition. |
| /// \param Loc Location number 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 [out] Kills Append end points of VNI's live range to Kills. |
| /// \param LIS Live intervals analysis. |
| void extendDef(SlotIndex Idx, DbgValueLocation Loc, |
| LiveRange *LR, const VNInfo *VNI, |
| SmallVectorImpl<SlotIndex> *Kills, |
| LiveIntervals &LIS); |
| |
| /// The value in LI/LocNo 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 LocNo Location number of LI->reg. |
| /// \param WasIndirect Indicates if the original use of LI->reg was indirect |
| /// \param Kills Points where the range of LocNo could be extended. |
| /// \param [in,out] NewDefs Append (Idx, LocNo) of inserted defs here. |
| void addDefsFromCopies( |
| LiveInterval *LI, unsigned LocNo, bool WasIndirect, |
| const SmallVectorImpl<SlotIndex> &Kills, |
| SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs, |
| MachineRegisterInfo &MRI, LiveIntervals &LIS); |
| |
| /// Compute the live intervals of all locations after collecting all their |
| /// def points. |
| void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI, |
| LiveIntervals &LIS, LexicalScopes &LS); |
| |
| /// Replace OldReg ranges with NewRegs ranges where NewRegs is |
| /// live. Returns true if any changes were made. |
| bool splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, |
| LiveIntervals &LIS); |
| |
| /// Rewrite virtual register locations according to the provided virtual |
| /// register map. Record the stack slot offsets for the locations that |
| /// were spilled. |
| void rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF, |
| const TargetInstrInfo &TII, |
| const TargetRegisterInfo &TRI, |
| SpillOffsetMap &SpillOffsets); |
| |
| /// Recreate DBG_VALUE instruction from data structures. |
| void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, |
| const TargetInstrInfo &TII, |
| const TargetRegisterInfo &TRI, |
| const SpillOffsetMap &SpillOffsets); |
| |
| /// Return DebugLoc of this UserValue. |
| DebugLoc getDebugLoc() { return dl;} |
| |
| void print(raw_ostream &, const TargetRegisterInfo *); |
| }; |
| |
| /// A user label is a part of a debug info user label. |
| class UserLabel { |
| const DILabel *Label; ///< The debug info label we are part of. |
| DebugLoc dl; ///< The debug location for the label. This is |
| ///< used by dwarf writer to find lexical scope. |
| SlotIndex loc; ///< Slot used by the debug label. |
| |
| /// Insert a DBG_LABEL into MBB at Idx. |
| void insertDebugLabel(MachineBasicBlock *MBB, SlotIndex Idx, |
| LiveIntervals &LIS, const TargetInstrInfo &TII); |
| |
| public: |
| /// Create a new UserLabel. |
| UserLabel(const DILabel *label, DebugLoc L, SlotIndex Idx) |
| : Label(label), dl(std::move(L)), loc(Idx) {} |
| |
| /// Does this UserLabel match the parameters? |
| bool match(const DILabel *L, const DILocation *IA, |
| const SlotIndex Index) const { |
| return Label == L && dl->getInlinedAt() == IA && loc == Index; |
| } |
| |
| /// Recreate DBG_LABEL instruction from data structures. |
| void emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII); |
| |
| /// Return DebugLoc of this UserLabel. |
| DebugLoc getDebugLoc() { return dl; } |
| |
| void print(raw_ostream &, const TargetRegisterInfo *); |
| }; |
| |
| /// Implementation of the LiveDebugVariables pass. |
| class LDVImpl { |
| LiveDebugVariables &pass; |
| LocMap::Allocator allocator; |
| MachineFunction *MF = nullptr; |
| LiveIntervals *LIS; |
| const TargetRegisterInfo *TRI; |
| |
| /// Whether emitDebugValues is called. |
| bool EmitDone = false; |
| |
| /// Whether the machine function is modified during the pass. |
| bool ModifiedMF = false; |
| |
| /// All allocated UserValue instances. |
| SmallVector<std::unique_ptr<UserValue>, 8> userValues; |
| |
| /// All allocated UserLabel instances. |
| SmallVector<std::unique_ptr<UserLabel>, 2> userLabels; |
| |
| /// Map virtual register to eq class leader. |
| using VRMap = DenseMap<unsigned, UserValue *>; |
| VRMap virtRegToEqClass; |
| |
| /// Map user variable to eq class leader. |
| using UVMap = DenseMap<const DILocalVariable *, UserValue *>; |
| UVMap userVarMap; |
| |
| /// Find or create a UserValue. |
| UserValue *getUserValue(const DILocalVariable *Var, const DIExpression *Expr, |
| const DebugLoc &DL); |
| |
| /// Find the EC leader for VirtReg or null. |
| UserValue *lookupVirtReg(unsigned VirtReg); |
| |
| /// Add DBG_VALUE instruction to our maps. |
| /// |
| /// \param MI DBG_VALUE instruction |
| /// \param Idx Last valid SLotIndex before instruction. |
| /// |
| /// \returns True if the DBG_VALUE instruction should be deleted. |
| bool handleDebugValue(MachineInstr &MI, SlotIndex Idx); |
| |
| /// Add DBG_LABEL instruction to UserLabel. |
| /// |
| /// \param MI DBG_LABEL instruction |
| /// \param Idx Last valid SlotIndex before instruction. |
| /// |
| /// \returns True if the DBG_LABEL instruction should be deleted. |
| bool handleDebugLabel(MachineInstr &MI, SlotIndex Idx); |
| |
| /// Collect and erase all DBG_VALUE instructions, adding a UserValue def |
| /// for each instruction. |
| /// |
| /// \param mf MachineFunction to be scanned. |
| /// |
| /// \returns True if any debug values were found. |
| bool collectDebugValues(MachineFunction &mf); |
| |
| /// Compute the live intervals of all user values after collecting all |
| /// their def points. |
| void computeIntervals(); |
| |
| public: |
| LDVImpl(LiveDebugVariables *ps) : pass(*ps) {} |
| |
| bool runOnMachineFunction(MachineFunction &mf); |
| |
| /// Release all memory. |
| void clear() { |
| MF = nullptr; |
| userValues.clear(); |
| userLabels.clear(); |
| virtRegToEqClass.clear(); |
| userVarMap.clear(); |
| // Make sure we call emitDebugValues if the machine function was modified. |
| assert((!ModifiedMF || EmitDone) && |
| "Dbg values are not emitted in LDV"); |
| EmitDone = false; |
| ModifiedMF = false; |
| } |
| |
| /// Map virtual register to an equivalence class. |
| void mapVirtReg(unsigned VirtReg, UserValue *EC); |
| |
| /// Replace all references to OldReg with NewRegs. |
| void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs); |
| |
| /// Recreate DBG_VALUE instruction from data structures. |
| void emitDebugValues(VirtRegMap *VRM); |
| |
| void print(raw_ostream&); |
| }; |
| |
| } // end anonymous namespace |
| |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS, |
| const LLVMContext &Ctx) { |
| if (!DL) |
| return; |
| |
| auto *Scope = cast<DIScope>(DL.getScope()); |
| // Omit the directory, because it's likely to be long and uninteresting. |
| CommentOS << Scope->getFilename(); |
| CommentOS << ':' << DL.getLine(); |
| if (DL.getCol() != 0) |
| CommentOS << ':' << DL.getCol(); |
| |
| DebugLoc InlinedAtDL = DL.getInlinedAt(); |
| if (!InlinedAtDL) |
| return; |
| |
| CommentOS << " @[ "; |
| printDebugLoc(InlinedAtDL, CommentOS, Ctx); |
| CommentOS << " ]"; |
| } |
| |
| static void printExtendedName(raw_ostream &OS, const DINode *Node, |
| const DILocation *DL) { |
| const LLVMContext &Ctx = Node->getContext(); |
| StringRef Res; |
| unsigned Line; |
| if (const auto *V = dyn_cast<const DILocalVariable>(Node)) { |
| Res = V->getName(); |
| Line = V->getLine(); |
| } else if (const auto *L = dyn_cast<const DILabel>(Node)) { |
| Res = L->getName(); |
| Line = L->getLine(); |
| } |
| |
| if (!Res.empty()) |
| OS << Res << "," << Line; |
| if (auto *InlinedAt = DL->getInlinedAt()) { |
| if (DebugLoc InlinedAtDL = InlinedAt) { |
| OS << " @["; |
| printDebugLoc(InlinedAtDL, OS, Ctx); |
| OS << "]"; |
| } |
| } |
| } |
| |
| void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) { |
| OS << "!\""; |
| printExtendedName(OS, Variable, dl); |
| |
| OS << "\"\t"; |
| for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) { |
| OS << " [" << I.start() << ';' << I.stop() << "):"; |
| if (I.value().isUndef()) |
| OS << "undef"; |
| else { |
| OS << I.value().locNo(); |
| if (I.value().wasIndirect()) |
| OS << " ind"; |
| } |
| } |
| for (unsigned i = 0, e = locations.size(); i != e; ++i) { |
| OS << " Loc" << i << '='; |
| locations[i].print(OS, TRI); |
| } |
| OS << '\n'; |
| } |
| |
| void UserLabel::print(raw_ostream &OS, const TargetRegisterInfo *TRI) { |
| OS << "!\""; |
| printExtendedName(OS, Label, dl); |
| |
| OS << "\"\t"; |
| OS << loc; |
| OS << '\n'; |
| } |
| |
| void LDVImpl::print(raw_ostream &OS) { |
| OS << "********** DEBUG VARIABLES **********\n"; |
| for (auto &userValue : userValues) |
| userValue->print(OS, TRI); |
| OS << "********** DEBUG LABELS **********\n"; |
| for (auto &userLabel : userLabels) |
| userLabel->print(OS, TRI); |
| } |
| #endif |
| |
| void UserValue::mapVirtRegs(LDVImpl *LDV) { |
| for (unsigned i = 0, e = locations.size(); i != e; ++i) |
| if (locations[i].isReg() && |
| TargetRegisterInfo::isVirtualRegister(locations[i].getReg())) |
| LDV->mapVirtReg(locations[i].getReg(), this); |
| } |
| |
| UserValue *LDVImpl::getUserValue(const DILocalVariable *Var, |
| const DIExpression *Expr, const DebugLoc &DL) { |
| UserValue *&Leader = userVarMap[Var]; |
| if (Leader) { |
| UserValue *UV = Leader->getLeader(); |
| Leader = UV; |
| for (; UV; UV = UV->getNext()) |
| if (UV->match(Var, Expr, DL->getInlinedAt())) |
| return UV; |
| } |
| |
| userValues.push_back( |
| llvm::make_unique<UserValue>(Var, Expr, DL, allocator)); |
| UserValue *UV = userValues.back().get(); |
| Leader = UserValue::merge(Leader, UV); |
| return UV; |
| } |
| |
| void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) { |
| assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs"); |
| UserValue *&Leader = virtRegToEqClass[VirtReg]; |
| Leader = UserValue::merge(Leader, EC); |
| } |
| |
| UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) { |
| if (UserValue *UV = virtRegToEqClass.lookup(VirtReg)) |
| return UV->getLeader(); |
| return nullptr; |
| } |
| |
| bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) { |
| // DBG_VALUE loc, offset, variable |
| if (MI.getNumOperands() != 4 || |
| !(MI.getOperand(1).isReg() || MI.getOperand(1).isImm()) || |
| !MI.getOperand(2).isMetadata()) { |
| LLVM_DEBUG(dbgs() << "Can't handle " << MI); |
| return false; |
| } |
| |
| // Detect invalid DBG_VALUE instructions, with a debug-use of a virtual |
| // register that hasn't been defined yet. If we do not remove those here, then |
| // the re-insertion of the DBG_VALUE instruction after register allocation |
| // will be incorrect. |
| // TODO: If earlier passes are corrected to generate sane debug information |
| // (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.getOperand(0).isReg() && |
| TargetRegisterInfo::isVirtualRegister(MI.getOperand(0).getReg())) { |
| const unsigned Reg = MI.getOperand(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. |
| Discard = true; |
| LLVM_DEBUG(dbgs() << "Discarding debug info (reg not live): " << Idx |
| << " " << MI); |
| } |
| } |
| } |
| |
| // Get or create the UserValue for (variable,offset) here. |
| bool IsIndirect = MI.getOperand(1).isImm(); |
| if (IsIndirect) |
| assert(MI.getOperand(1).getImm() == 0 && "DBG_VALUE with nonzero offset"); |
| const DILocalVariable *Var = MI.getDebugVariable(); |
| const DIExpression *Expr = MI.getDebugExpression(); |
| UserValue *UV = |
| getUserValue(Var, Expr, MI.getDebugLoc()); |
| if (!Discard) |
| UV->addDef(Idx, MI.getOperand(0), IsIndirect); |
| else { |
| MachineOperand MO = MachineOperand::CreateReg(0U, false); |
| MO.setIsDebug(); |
| UV->addDef(Idx, MO, false); |
| } |
| return true; |
| } |
| |
| bool LDVImpl::handleDebugLabel(MachineInstr &MI, SlotIndex Idx) { |
| // DBG_LABEL label |
| if (MI.getNumOperands() != 1 || !MI.getOperand(0).isMetadata()) { |
| LLVM_DEBUG(dbgs() << "Can't handle " << MI); |
| return false; |
| } |
| |
| // Get or create the UserLabel for label here. |
| const DILabel *Label = MI.getDebugLabel(); |
| const DebugLoc &DL = MI.getDebugLoc(); |
| bool Found = false; |
| for (auto const &L : userLabels) { |
| if (L->match(Label, DL->getInlinedAt(), Idx)) { |
| Found = true; |
| break; |
| } |
| } |
| if (!Found) |
| userLabels.push_back(llvm::make_unique<UserLabel>(Label, DL, Idx)); |
| |
| return true; |
| } |
| |
| bool LDVImpl::collectDebugValues(MachineFunction &mf) { |
| 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(); |
| MBBI != MBBE;) { |
| // Use the first debug instruction in the sequence to get a SlotIndex |
| // for following consecutive debug instructions. |
| if (!MBBI->isDebugInstr()) { |
| ++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) |
| : 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->isDebugLabel() && handleDebugLabel(*MBBI, Idx))) { |
| MBBI = MBB->erase(MBBI); |
| Changed = true; |
| } else |
| ++MBBI; |
| } while (MBBI != MBBE && MBBI->isDebugInstr()); |
| } |
| } |
| return Changed; |
| } |
| |
| void UserValue::extendDef(SlotIndex Idx, DbgValueLocation Loc, LiveRange *LR, |
| const VNInfo *VNI, SmallVectorImpl<SlotIndex> *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) { |
| LiveInterval::Segment *Segment = LR->getSegmentContaining(Start); |
| if (!Segment || Segment->valno != VNI) { |
| if (Kills) |
| Kills->push_back(Start); |
| return; |
| } |
| if (Segment->end < Stop) { |
| Stop = Segment->end; |
| ToEnd = false; |
| } |
| } |
| |
| // There could already be a short def at Start. |
| if (I.valid() && I.start() <= Start) { |
| // Stop when meeting a different location or an already extended interval. |
| Start = Start.getNextSlot(); |
| if (I.value() != Loc || I.stop() != Start) |
| return; |
| // This is a one-slot placeholder. Just skip it. |
| ++I; |
| } |
| |
| // Limited by the next def. |
| if (I.valid() && I.start() < Stop) { |
| Stop = I.start(); |
| ToEnd = false; |
| } |
| // Limited by VNI's live range. |
| else if (!ToEnd && Kills) |
| Kills->push_back(Stop); |
| |
| if (Start < Stop) |
| I.insert(Start, Stop, Loc); |
| } |
| |
| void UserValue::addDefsFromCopies( |
| LiveInterval *LI, unsigned LocNo, bool WasIndirect, |
| const SmallVectorImpl<SlotIndex> &Kills, |
| SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs, |
| MachineRegisterInfo &MRI, LiveIntervals &LIS) { |
| if (Kills.empty()) |
| return; |
| // Don't track copies from physregs, there are too many uses. |
| if (!TargetRegisterInfo::isVirtualRegister(LI->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; |
| unsigned 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 (!TargetRegisterInfo::isVirtualRegister(DstReg)) |
| continue; |
| |
| // Is LocNo 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().locNo() != LocNo) |
| 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 (CopyValues.empty()) |
| return; |
| |
| LLVM_DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI |
| << '\n'); |
| |
| // 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) |
| continue; |
| LLVM_DEBUG(dbgs() << "Kill at " << Idx << " 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)); |
| DbgValueLocation NewLoc(LocNo, WasIndirect); |
| I.insert(Idx, Idx.getNextSlot(), NewLoc); |
| NewDefs.push_back(std::make_pair(Idx, NewLoc)); |
| break; |
| } |
| } |
| } |
| |
| void UserValue::computeIntervals(MachineRegisterInfo &MRI, |
| const TargetRegisterInfo &TRI, |
| LiveIntervals &LIS, LexicalScopes &LS) { |
| SmallVector<std::pair<SlotIndex, DbgValueLocation>, 16> Defs; |
| |
| // Collect all defs to be extended (Skipping undefs). |
| for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) |
| if (!I.value().isUndef()) |
| Defs.push_back(std::make_pair(I.start(), I.value())); |
| |
| // Extend all defs, and possibly add new ones along the way. |
| for (unsigned i = 0; i != Defs.size(); ++i) { |
| SlotIndex Idx = Defs[i].first; |
| DbgValueLocation Loc = Defs[i].second; |
| const MachineOperand &LocMO = locations[Loc.locNo()]; |
| |
| if (!LocMO.isReg()) { |
| extendDef(Idx, Loc, nullptr, nullptr, nullptr, LIS); |
| continue; |
| } |
| |
| // Register locations are constrained to where the register value is live. |
| if (TargetRegisterInfo::isVirtualRegister(LocMO.getReg())) { |
| 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, Loc, 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, Loc.locNo(), Loc.wasIndirect(), Kills, Defs, MRI, |
| LIS); |
| continue; |
| } |
| |
| // For physregs, we only mark the start slot idx. DwarfDebug will see it |
| // as if the DBG_VALUE is valid up until the end of the basic block, or |
| // the next def of the physical register. So we do not need to extend the |
| // range. It might actually happen that the DBG_VALUE is the last use of |
| // the physical register (e.g. if this is an unused input argument to a |
| // function). |
| } |
| |
| // The computed intervals may extend beyond the range of the debug |
| // 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. |
| |
| LexicalScope *Scope = LS.findLexicalScope(dl); |
| if (!Scope) |
| return; |
| |
| SlotIndex PrevEnd; |
| LocMap::iterator I = locInts.begin(); |
| |
| // Iterate over the lexical scope ranges. Each time round the loop |
| // we check the intervals for overlap with the end of the previous |
| // range and the start of the next. The first range is handled as |
| // a special case where there is no PrevEnd. |
| for (const InsnRange &Range : Scope->getRanges()) { |
| SlotIndex RStart = LIS.getInstructionIndex(*Range.first); |
| SlotIndex REnd = LIS.getInstructionIndex(*Range.second); |
| |
| // At the start of each iteration I has been advanced so that |
| // I.stop() >= PrevEnd. Check for overlap. |
| if (PrevEnd && I.start() < PrevEnd) { |
| SlotIndex IStop = I.stop(); |
| DbgValueLocation Loc = I.value(); |
| |
| // Stop overlaps previous end - trim the end of the interval to |
| // the scope range. |
| I.setStopUnchecked(PrevEnd); |
| ++I; |
| |
| // If the interval also overlaps the start of the "next" (i.e. |
| // current) range create a new interval for the remainder (which |
| // may be further trimmed). |
| if (RStart < IStop) |
| I.insert(RStart, IStop, Loc); |
| } |
| |
| // Advance I so that I.stop() >= RStart, and check for overlap. |
| I.advanceTo(RStart); |
| if (!I.valid()) |
| return; |
| |
| if (I.start() < RStart) { |
| // Interval start overlaps range - trim to the scope range. |
| I.setStartUnchecked(RStart); |
| // Remember that this interval was trimmed. |
| trimmedDefs.insert(RStart); |
| } |
| |
| // The end of a lexical scope range is the last instruction in the |
| // range. To convert to an interval we need the index of the |
| // instruction after it. |
| REnd = REnd.getNextIndex(); |
| |
| // Advance I to first interval outside current range. |
| I.advanceTo(REnd); |
| if (!I.valid()) |
| return; |
| |
| PrevEnd = REnd; |
| } |
| |
| // Check for overlap with end of final range. |
| if (PrevEnd && I.start() < PrevEnd) |
| I.setStopUnchecked(PrevEnd); |
| } |
| |
| void LDVImpl::computeIntervals() { |
| LexicalScopes LS; |
| LS.initialize(*MF); |
| |
| for (unsigned i = 0, e = userValues.size(); i != e; ++i) { |
| userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, LS); |
| userValues[i]->mapVirtRegs(this); |
| } |
| } |
| |
| bool LDVImpl::runOnMachineFunction(MachineFunction &mf) { |
| clear(); |
| MF = &mf; |
| LIS = &pass.getAnalysis<LiveIntervals>(); |
| TRI = mf.getSubtarget().getRegisterInfo(); |
| LLVM_DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: " |
| << mf.getName() << " **********\n"); |
| |
| bool Changed = collectDebugValues(mf); |
| computeIntervals(); |
| LLVM_DEBUG(print(dbgs())); |
| ModifiedMF = Changed; |
| return Changed; |
| } |
| |
| static void removeDebugValues(MachineFunction &mf) { |
| for (MachineBasicBlock &MBB : mf) { |
| for (auto MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ) { |
| if (!MBBI->isDebugValue()) { |
| ++MBBI; |
| continue; |
| } |
| MBBI = MBB.erase(MBBI); |
| } |
| } |
| } |
| |
| bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) { |
| if (!EnableLDV) |
| return false; |
| if (!mf.getFunction().getSubprogram()) { |
| removeDebugValues(mf); |
| return false; |
| } |
| if (!pImpl) |
| pImpl = new LDVImpl(this); |
| return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf); |
| } |
| |
| void LiveDebugVariables::releaseMemory() { |
| if (pImpl) |
| static_cast<LDVImpl*>(pImpl)->clear(); |
| } |
| |
| LiveDebugVariables::~LiveDebugVariables() { |
| if (pImpl) |
| delete static_cast<LDVImpl*>(pImpl); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Live Range Splitting |
| //===----------------------------------------------------------------------===// |
| |
| bool |
| UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs, |
| LiveIntervals& LIS) { |
| LLVM_DEBUG({ |
| dbgs() << "Splitting Loc" << OldLocNo << '\t'; |
| print(dbgs(), nullptr); |
| }); |
| bool DidChange = false; |
| LocMap::iterator LocMapI; |
| LocMapI.setMap(locInts); |
| for (unsigned i = 0; i != NewRegs.size(); ++i) { |
| LiveInterval *LI = &LIS.getInterval(NewRegs[i]); |
| if (LI->empty()) |
| continue; |
| |
| // Don't allocate the new LocNo until it is needed. |
| unsigned NewLocNo = UndefLocNo; |
| |
| // Iterate over the overlaps between locInts and LI. |
| LocMapI.find(LI->beginIndex()); |
| if (!LocMapI.valid()) |
| continue; |
| LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start()); |
| LiveInterval::iterator LIE = LI->end(); |
| while (LocMapI.valid() && LII != LIE) { |
| // At this point, we know that LocMapI.stop() > LII->start. |
| LII = LI->advanceTo(LII, LocMapI.start()); |
| if (LII == LIE) |
| break; |
| |
| // Now LII->end > LocMapI.start(). Do we have an overlap? |
| if (LocMapI.value().locNo() == OldLocNo && LII->start < LocMapI.stop()) { |
| // Overlapping correct location. Allocate NewLocNo now. |
| if (NewLocNo == UndefLocNo) { |
| MachineOperand MO = MachineOperand::CreateReg(LI->reg, false); |
| MO.setSubReg(locations[OldLocNo].getSubReg()); |
| NewLocNo = getLocationNo(MO); |
| DidChange = true; |
| } |
| |
| SlotIndex LStart = LocMapI.start(); |
| SlotIndex LStop = LocMapI.stop(); |
| DbgValueLocation OldLoc = LocMapI.value(); |
| |
| // Trim LocMapI down to the LII overlap. |
| if (LStart < LII->start) |
| LocMapI.setStartUnchecked(LII->start); |
| if (LStop > LII->end) |
| LocMapI.setStopUnchecked(LII->end); |
| |
| // Change the value in the overlap. This may trigger coalescing. |
| LocMapI.setValue(OldLoc.changeLocNo(NewLocNo)); |
| |
| // Re-insert any removed OldLocNo ranges. |
| if (LStart < LocMapI.start()) { |
| LocMapI.insert(LStart, LocMapI.start(), OldLoc); |
| ++LocMapI; |
| assert(LocMapI.valid() && "Unexpected coalescing"); |
| } |
| if (LStop > LocMapI.stop()) { |
| ++LocMapI; |
| LocMapI.insert(LII->end, LStop, OldLoc); |
| --LocMapI; |
| } |
| } |
| |
| // Advance to the next overlap. |
| if (LII->end < LocMapI.stop()) { |
| if (++LII == LIE) |
| break; |
| LocMapI.advanceTo(LII->start); |
| } else { |
| ++LocMapI; |
| if (!LocMapI.valid()) |
| break; |
| LII = LI->advanceTo(LII, LocMapI.start()); |
| } |
| } |
| } |
| |
| // Finally, remove any remaining OldLocNo intervals and OldLocNo itself. |
| locations.erase(locations.begin() + OldLocNo); |
| LocMapI.goToBegin(); |
| while (LocMapI.valid()) { |
| DbgValueLocation v = LocMapI.value(); |
| if (v.locNo() == OldLocNo) { |
| LLVM_DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';' |
| << LocMapI.stop() << ")\n"); |
| LocMapI.erase(); |
| } else { |
| // Undef values always have location number UndefLocNo, so don't change |
| // locNo in that case. See getLocationNo(). |
| if (!v.isUndef() && v.locNo() > OldLocNo) |
| LocMapI.setValueUnchecked(v.changeLocNo(v.locNo() - 1)); |
| ++LocMapI; |
| } |
| } |
| |
| LLVM_DEBUG({ |
| dbgs() << "Split result: \t"; |
| print(dbgs(), nullptr); |
| }); |
| return DidChange; |
| } |
| |
| bool |
| UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, |
| LiveIntervals &LIS) { |
| bool DidChange = false; |
| // Split locations referring to OldReg. Iterate backwards so splitLocation can |
| // safely erase unused locations. |
| for (unsigned i = locations.size(); i ; --i) { |
| unsigned LocNo = i-1; |
| const MachineOperand *Loc = &locations[LocNo]; |
| if (!Loc->isReg() || Loc->getReg() != OldReg) |
| continue; |
| DidChange |= splitLocation(LocNo, NewRegs, LIS); |
| } |
| return DidChange; |
| } |
| |
| void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) { |
| bool DidChange = false; |
| for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext()) |
| DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS); |
| |
| if (!DidChange) |
| return; |
| |
| // Map all of the new virtual registers. |
| UserValue *UV = lookupVirtReg(OldReg); |
| for (unsigned i = 0; i != NewRegs.size(); ++i) |
| mapVirtReg(NewRegs[i], UV); |
| } |
| |
| void LiveDebugVariables:: |
| splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) { |
| if (pImpl) |
| static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs); |
| } |
| |
| void UserValue::rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF, |
| const TargetInstrInfo &TII, |
| const TargetRegisterInfo &TRI, |
| SpillOffsetMap &SpillOffsets) { |
| // Build a set of new locations with new numbers so we can coalesce our |
| // IntervalMap if two vreg intervals collapse to the same physical location. |
| // Use MapVector instead of SetVector because MapVector::insert returns the |
| // position of the previously or newly inserted element. The boolean value |
| // tracks if the location was produced by a spill. |
| // FIXME: This will be problematic if we ever support direct and indirect |
| // frame index locations, i.e. expressing both variables in memory and |
| // 'int x, *px = &x'. The "spilled" bit must become part of the location. |
| MapVector<MachineOperand, std::pair<bool, unsigned>> NewLocations; |
| SmallVector<unsigned, 4> LocNoMap(locations.size()); |
| for (unsigned I = 0, E = locations.size(); I != E; ++I) { |
| bool Spilled = false; |
| unsigned SpillOffset = 0; |
| MachineOperand Loc = locations[I]; |
| // Only virtual registers are rewritten. |
| if (Loc.isReg() && Loc.getReg() && |
| TargetRegisterInfo::isVirtualRegister(Loc.getReg())) { |
| unsigned VirtReg = Loc.getReg(); |
| if (VRM.isAssignedReg(VirtReg) && |
| TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) { |
| // This can create a %noreg operand in rare cases when the sub-register |
| // index is no longer available. That means the user value is in a |
| // non-existent sub-register, and %noreg is exactly what we want. |
| Loc.substPhysReg(VRM.getPhys(VirtReg), TRI); |
| } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) { |
| // Retrieve the stack slot offset. |
| unsigned SpillSize; |
| const MachineRegisterInfo &MRI = MF.getRegInfo(); |
| const TargetRegisterClass *TRC = MRI.getRegClass(VirtReg); |
| bool Success = TII.getStackSlotRange(TRC, Loc.getSubReg(), SpillSize, |
| SpillOffset, MF); |
| |
| // FIXME: Invalidate the location if the offset couldn't be calculated. |
| (void)Success; |
| |
| Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg)); |
| Spilled = true; |
| } else { |
| Loc.setReg(0); |
| Loc.setSubReg(0); |
| } |
| } |
| |
| // Insert this location if it doesn't already exist and record a mapping |
| // from the old number to the new number. |
| auto InsertResult = NewLocations.insert({Loc, {Spilled, SpillOffset}}); |
| unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first); |
| LocNoMap[I] = NewLocNo; |
| } |
| |
| // Rewrite the locations and record the stack slot offsets for spills. |
| locations.clear(); |
| SpillOffsets.clear(); |
| for (auto &Pair : NewLocations) { |
| bool Spilled; |
| unsigned SpillOffset; |
| std::tie(Spilled, SpillOffset) = Pair.second; |
| locations.push_back(Pair.first); |
| if (Spilled) { |
| unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair); |
| SpillOffsets[NewLocNo] = SpillOffset; |
| } |
| } |
| |
| // Update the interval map, but only coalesce left, since intervals to the |
| // right use the old location numbers. This should merge two contiguous |
| // DBG_VALUE intervals with different vregs that were allocated to the same |
| // physical register. |
| for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) { |
| DbgValueLocation Loc = I.value(); |
| // Undef values don't exist in locations (and thus not in LocNoMap either) |
| // so skip over them. See getLocationNo(). |
| if (Loc.isUndef()) |
| continue; |
| unsigned NewLocNo = LocNoMap[Loc.locNo()]; |
| I.setValueUnchecked(Loc.changeLocNo(NewLocNo)); |
| I.setStart(I.start()); |
| } |
| } |
| |
| /// Find an iterator for inserting a DBG_VALUE instruction. |
| static MachineBasicBlock::iterator |
| findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, |
| LiveIntervals &LIS) { |
| SlotIndex Start = LIS.getMBBStartIdx(MBB); |
| Idx = Idx.getBaseIndex(); |
| |
| // Try to find an insert location by going backwards from Idx. |
| MachineInstr *MI; |
| while (!(MI = LIS.getInstructionFromIndex(Idx))) { |
| // We've reached the beginning of MBB. |
| if (Idx == Start) { |
| MachineBasicBlock::iterator I = MBB->SkipPHIsLabelsAndDebug(MBB->begin()); |
| return I; |
| } |
| Idx = Idx.getPrevIndex(); |
| } |
| |
| // Don't insert anything after the first terminator, though. |
| return MI->isTerminator() ? MBB->getFirstTerminator() : |
| std::next(MachineBasicBlock::iterator(MI)); |
| } |
| |
| /// 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()) |
| return MBB->instr_end(); |
| unsigned 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)) |
| // The insert location is directly after the instruction/bundle. |
| return std::next(I); |
| ++I; |
| } |
| return MBB->end(); |
| } |
| |
| void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx, |
| SlotIndex StopIdx, DbgValueLocation Loc, |
| bool Spilled, unsigned SpillOffset, |
| LiveIntervals &LIS, const TargetInstrInfo &TII, |
| const TargetRegisterInfo &TRI) { |
| SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB); |
| // Only search within the current MBB. |
| StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx; |
| MachineBasicBlock::iterator I = findInsertLocation(MBB, StartIdx, LIS); |
| // Undef values don't exist in locations so create new "noreg" register MOs |
| // for them. See getLocationNo(). |
| MachineOperand MO = !Loc.isUndef() ? |
| locations[Loc.locNo()] : |
| MachineOperand::CreateReg(/* Reg */ 0, /* isDef */ false, /* isImp */ false, |
| /* isKill */ false, /* isDead */ false, |
| /* isUndef */ false, /* isEarlyClobber */ false, |
| /* SubReg */ 0, /* isDebug */ true); |
| |
| ++NumInsertedDebugValues; |
| |
| assert(cast<DILocalVariable>(Variable) |
| ->isValidLocationForIntrinsic(getDebugLoc()) && |
| "Expected inlined-at fields to agree"); |
| |
| // If the location was spilled, the new DBG_VALUE will be indirect. If the |
| // original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate |
| // that the original virtual register was a pointer. Also, add the stack slot |
| // offset for the spilled register to the expression. |
| const DIExpression *Expr = Expression; |
| bool IsIndirect = Loc.wasIndirect(); |
| if (Spilled) { |
| auto Deref = IsIndirect ? DIExpression::WithDeref : DIExpression::NoDeref; |
| Expr = |
| DIExpression::prepend(Expr, DIExpression::NoDeref, SpillOffset, Deref); |
| IsIndirect = true; |
| } |
| |
| assert((!Spilled || MO.isFI()) && "a spilled location must be a frame index"); |
| |
| do { |
| BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE), |
| IsIndirect, MO, Variable, Expr); |
| |
| // Continue and insert DBG_VALUES after every redefinition of register |
| // associated with the debug value within the range |
| I = findNextInsertLocation(MBB, I, StopIdx, MO, 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); |
| ++NumInsertedDebugLabels; |
| BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_LABEL)) |
| .addMetadata(Label); |
| } |
| |
| void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, |
| const TargetInstrInfo &TII, |
| const TargetRegisterInfo &TRI, |
| const SpillOffsetMap &SpillOffsets) { |
| MachineFunction::iterator MFEnd = VRM->getMachineFunction().end(); |
| |
| for (LocMap::const_iterator I = locInts.begin(); I.valid();) { |
| SlotIndex Start = I.start(); |
| SlotIndex Stop = I.stop(); |
| DbgValueLocation Loc = I.value(); |
| auto SpillIt = |
| !Loc.isUndef() ? SpillOffsets.find(Loc.locNo()) : SpillOffsets.end(); |
| bool Spilled = SpillIt != SpillOffsets.end(); |
| unsigned SpillOffset = 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 |
| // first instruction in the range). |
| if (trimmedDefs.count(Start)) |
| Start = Start.getPrevIndex(); |
| |
| LLVM_DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << Loc.locNo()); |
| MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator(); |
| SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB); |
| |
| LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd); |
| insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII, |
| TRI); |
| // This interval may span multiple basic blocks. |
| // Insert a DBG_VALUE into each one. |
| while (Stop > MBBEnd) { |
| // Move to the next block. |
| Start = MBBEnd; |
| if (++MBB == MFEnd) |
| break; |
| MBBEnd = LIS.getMBBEndIdx(&*MBB); |
| LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd); |
| insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII, |
| TRI); |
| } |
| LLVM_DEBUG(dbgs() << '\n'); |
| if (MBB == MFEnd) |
| break; |
| |
| ++I; |
| } |
| } |
| |
| void UserLabel::emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII) { |
| LLVM_DEBUG(dbgs() << "\t" << loc); |
| MachineFunction::iterator MBB = LIS.getMBBFromIndex(loc)->getIterator(); |
| |
| LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB)); |
| insertDebugLabel(&*MBB, loc, LIS, TII); |
| |
| LLVM_DEBUG(dbgs() << '\n'); |
| } |
| |
| void LDVImpl::emitDebugValues(VirtRegMap *VRM) { |
| LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"); |
| if (!MF) |
| return; |
| 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); |
| } |
| LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG LABELS **********\n"); |
| for (auto &userLabel : userLabels) { |
| LLVM_DEBUG(userLabel->print(dbgs(), TRI)); |
| userLabel->emitDebugLabel(*LIS, *TII); |
| } |
| EmitDone = true; |
| } |
| |
| void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) { |
| if (pImpl) |
| static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM); |
| } |
| |
| bool LiveDebugVariables::doInitialization(Module &M) { |
| return Pass::doInitialization(M); |
| } |
| |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| LLVM_DUMP_METHOD void LiveDebugVariables::dump() const { |
| if (pImpl) |
| static_cast<LDVImpl*>(pImpl)->print(dbgs()); |
| } |
| #endif |