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Diffstat (limited to 'contrib/llvm/lib/CodeGen/LiveDebugVariables.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/LiveDebugVariables.cpp | 1010 |
1 files changed, 1010 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/LiveDebugVariables.cpp b/contrib/llvm/lib/CodeGen/LiveDebugVariables.cpp new file mode 100644 index 0000000..2187833 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/LiveDebugVariables.cpp @@ -0,0 +1,1010 @@ +//===- LiveDebugVariables.cpp - Tracking debug info variables -------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// 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. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "livedebug" +#include "LiveDebugVariables.h" +#include "VirtRegMap.h" +#include "llvm/Constants.h" +#include "llvm/Metadata.h" +#include "llvm/Value.h" +#include "llvm/Analysis/DebugInfo.h" +#include "llvm/ADT/IntervalMap.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/CodeGen/LexicalScopes.h" +#include "llvm/CodeGen/LiveIntervalAnalysis.h" +#include "llvm/CodeGen/MachineDominators.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" + +using namespace llvm; + +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"); +char LiveDebugVariables::ID = 0; + +INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars", + "Debug Variable Analysis", false, false) +INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) +INITIALIZE_PASS_DEPENDENCY(LiveIntervals) +INITIALIZE_PASS_END(LiveDebugVariables, "livedebugvars", + "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), pImpl(0) { + initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry()); +} + +/// LocMap - Map of where a user value is live, and its location. +typedef IntervalMap<SlotIndex, unsigned, 4> LocMap; + +namespace { +/// UserValueScopes - Keeps track of lexical scopes associated with an +/// user value's source location. +class UserValueScopes { + DebugLoc DL; + LexicalScopes &LS; + SmallPtrSet<const MachineBasicBlock *, 4> LBlocks; + +public: + UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(D), LS(L) {} + + /// dominates - Return true if current scope dominates at least one machine + /// instruction in a given machine basic block. + bool dominates(MachineBasicBlock *MBB) { + if (LBlocks.empty()) + LS.getMachineBasicBlocks(DL, LBlocks); + if (LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB)) + return true; + return false; + } +}; +} // end anonymous namespace + +/// UserValue - 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. +namespace { +class LDVImpl; +class UserValue { + const MDNode *variable; ///< The debug info variable we are part of. + unsigned offset; ///< Byte offset into variable. + 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; ///< 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; + + /// coalesceLocation - After LocNo was changed, check if it has become + /// identical to another location, and coalesce them. This may cause LocNo or + /// a later location to be erased, but no earlier location will be erased. + void coalesceLocation(unsigned LocNo); + + /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo. + void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo, + LiveIntervals &LIS, const TargetInstrInfo &TII); + + /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs + /// is live. Returns true if any changes were made. + bool splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs); + +public: + /// UserValue - Create a new UserValue. + UserValue(const MDNode *var, unsigned o, DebugLoc L, + LocMap::Allocator &alloc) + : variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc) + {} + + /// getLeader - Get the leader of this value's equivalence class. + UserValue *getLeader() { + UserValue *l = leader; + while (l != l->leader) + l = l->leader; + return leader = l; + } + + /// getNext - Return the next UserValue in the equivalence class. + UserValue *getNext() const { return next; } + + /// match - Does this UserValue match the parameters? + bool match(const MDNode *Var, unsigned Offset) const { + return Var == variable && Offset == offset; + } + + /// merge - 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; + } + + /// getLocationNo - Return the location number that matches Loc. + unsigned getLocationNo(const MachineOperand &LocMO) { + if (LocMO.isReg()) { + if (LocMO.getReg() == 0) + return ~0u; + // 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()) + locations.back().setIsUse(); + return locations.size() - 1; + } + + /// mapVirtRegs - Ensure that all virtual register locations are mapped. + void mapVirtRegs(LDVImpl *LDV); + + /// addDef - Add a definition point to this value. + void addDef(SlotIndex Idx, const MachineOperand &LocMO) { + // Add a singular (Idx,Idx) -> Loc mapping. + LocMap::iterator I = locInts.find(Idx); + if (!I.valid() || I.start() != Idx) + I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO)); + else + // A later DBG_VALUE at the same SlotIndex overrides the old location. + I.setValue(getLocationNo(LocMO)); + } + + /// extendDef - Extend the current definition as far as possible down the + /// dominator tree. 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. + /// @param Idx Starting point for the definition. + /// @param LocNo Location number to propagate. + /// @param LI Restrict liveness to where LI has the value VNI. May be null. + /// @param VNI When LI is not null, this is the value to restrict to. + /// @param Kills Append end points of VNI's live range to Kills. + /// @param LIS Live intervals analysis. + /// @param MDT Dominator tree. + void extendDef(SlotIndex Idx, unsigned LocNo, + LiveInterval *LI, const VNInfo *VNI, + SmallVectorImpl<SlotIndex> *Kills, + LiveIntervals &LIS, MachineDominatorTree &MDT, + UserValueScopes &UVS); + + /// addDefsFromCopies - 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 Kills Points where the range of LocNo could be extended. + /// @param NewDefs Append (Idx, LocNo) of inserted defs here. + void addDefsFromCopies(LiveInterval *LI, unsigned LocNo, + const SmallVectorImpl<SlotIndex> &Kills, + SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs, + MachineRegisterInfo &MRI, + LiveIntervals &LIS); + + /// computeIntervals - Compute the live intervals of all locations after + /// collecting all their def points. + void computeIntervals(MachineRegisterInfo &MRI, + LiveIntervals &LIS, MachineDominatorTree &MDT, + UserValueScopes &UVS); + + /// renameRegister - Update locations to rewrite OldReg as NewReg:SubIdx. + void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx, + const TargetRegisterInfo *TRI); + + /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is + /// live. Returns true if any changes were made. + bool splitRegister(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs); + + /// rewriteLocations - Rewrite virtual register locations according to the + /// provided virtual register map. + void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI); + + /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures. + void emitDebugValues(VirtRegMap *VRM, + LiveIntervals &LIS, const TargetInstrInfo &TRI); + + /// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A + /// variable may have more than one corresponding DBG_VALUE instructions. + /// Only first one needs DebugLoc to identify variable's lexical scope + /// in source file. + DebugLoc findDebugLoc(); + + /// getDebugLoc - Return DebugLoc of this UserValue. + DebugLoc getDebugLoc() { return dl;} + void print(raw_ostream&, const TargetMachine*); +}; +} // namespace + +/// LDVImpl - Implementation of the LiveDebugVariables pass. +namespace { +class LDVImpl { + LiveDebugVariables &pass; + LocMap::Allocator allocator; + MachineFunction *MF; + LiveIntervals *LIS; + LexicalScopes LS; + MachineDominatorTree *MDT; + const TargetRegisterInfo *TRI; + + /// userValues - All allocated UserValue instances. + SmallVector<UserValue*, 8> userValues; + + /// Map virtual register to eq class leader. + typedef DenseMap<unsigned, UserValue*> VRMap; + VRMap virtRegToEqClass; + + /// Map user variable to eq class leader. + typedef DenseMap<const MDNode *, UserValue*> UVMap; + UVMap userVarMap; + + /// getUserValue - Find or create a UserValue. + UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL); + + /// lookupVirtReg - Find the EC leader for VirtReg or null. + UserValue *lookupVirtReg(unsigned VirtReg); + + /// handleDebugValue - Add DBG_VALUE instruction to our maps. + /// @param MI DBG_VALUE instruction + /// @param Idx Last valid SLotIndex before instruction. + /// @return True if the DBG_VALUE instruction should be deleted. + bool handleDebugValue(MachineInstr *MI, SlotIndex Idx); + + /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding + /// a UserValue def for each instruction. + /// @param mf MachineFunction to be scanned. + /// @return True if any debug values were found. + bool collectDebugValues(MachineFunction &mf); + + /// computeIntervals - 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); + + /// clear - Relase all memory. + void clear() { + DeleteContainerPointers(userValues); + userValues.clear(); + virtRegToEqClass.clear(); + userVarMap.clear(); + } + + /// mapVirtReg - Map virtual register to an equivalence class. + void mapVirtReg(unsigned VirtReg, UserValue *EC); + + /// renameRegister - Replace all references to OldReg with NewReg:SubIdx. + void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx); + + /// splitRegister - Replace all references to OldReg with NewRegs. + void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs); + + /// emitDebugVariables - Recreate DBG_VALUE instruction from data structures. + void emitDebugValues(VirtRegMap *VRM); + + void print(raw_ostream&); +}; +} // namespace + +void UserValue::print(raw_ostream &OS, const TargetMachine *TM) { + DIVariable DV(variable); + OS << "!\""; + DV.printExtendedName(OS); + OS << "\"\t"; + if (offset) + OS << '+' << offset; + for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) { + OS << " [" << I.start() << ';' << I.stop() << "):"; + if (I.value() == ~0u) + OS << "undef"; + else + OS << I.value(); + } + for (unsigned i = 0, e = locations.size(); i != e; ++i) { + OS << " Loc" << i << '='; + locations[i].print(OS, TM); + } + OS << '\n'; +} + +void LDVImpl::print(raw_ostream &OS) { + OS << "********** DEBUG VARIABLES **********\n"; + for (unsigned i = 0, e = userValues.size(); i != e; ++i) + userValues[i]->print(OS, &MF->getTarget()); +} + +void UserValue::coalesceLocation(unsigned LocNo) { + unsigned KeepLoc = 0; + for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) { + if (KeepLoc == LocNo) + continue; + if (locations[KeepLoc].isIdenticalTo(locations[LocNo])) + break; + } + // No matches. + if (KeepLoc == locations.size()) + return; + + // Keep the smaller location, erase the larger one. + unsigned EraseLoc = LocNo; + if (KeepLoc > EraseLoc) + std::swap(KeepLoc, EraseLoc); + locations.erase(locations.begin() + EraseLoc); + + // Rewrite values. + for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) { + unsigned v = I.value(); + if (v == EraseLoc) + I.setValue(KeepLoc); // Coalesce when possible. + else if (v > EraseLoc) + I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values. + } +} + +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 MDNode *Var, unsigned Offset, + DebugLoc DL) { + UserValue *&Leader = userVarMap[Var]; + if (Leader) { + UserValue *UV = Leader->getLeader(); + Leader = UV; + for (; UV; UV = UV->getNext()) + if (UV->match(Var, Offset)) + return UV; + } + + UserValue *UV = new UserValue(Var, Offset, DL, allocator); + userValues.push_back(UV); + 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 0; +} + +bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) { + // DBG_VALUE loc, offset, variable + if (MI->getNumOperands() != 3 || + !MI->getOperand(1).isImm() || !MI->getOperand(2).isMetadata()) { + DEBUG(dbgs() << "Can't handle " << *MI); + return false; + } + + // Get or create the UserValue for (variable,offset). + unsigned Offset = MI->getOperand(1).getImm(); + const MDNode *Var = MI->getOperand(2).getMetadata(); + UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc()); + UV->addDef(Idx, MI->getOperand(0)); + 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;) { + if (!MBBI->isDebugValue()) { + ++MBBI; + continue; + } + // DBG_VALUE has no slot index, use the previous instruction instead. + SlotIndex Idx = MBBI == MBB->begin() ? + LIS->getMBBStartIdx(MBB) : + LIS->getInstructionIndex(llvm::prior(MBBI)).getRegSlot(); + // Handle consecutive DBG_VALUE instructions with the same slot index. + do { + if (handleDebugValue(MBBI, Idx)) { + MBBI = MBB->erase(MBBI); + Changed = true; + } else + ++MBBI; + } while (MBBI != MBBE && MBBI->isDebugValue()); + } + } + return Changed; +} + +void UserValue::extendDef(SlotIndex Idx, unsigned LocNo, + LiveInterval *LI, const VNInfo *VNI, + SmallVectorImpl<SlotIndex> *Kills, + LiveIntervals &LIS, MachineDominatorTree &MDT, + UserValueScopes &UVS) { + SmallVector<SlotIndex, 16> Todo; + Todo.push_back(Idx); + do { + SlotIndex Start = Todo.pop_back_val(); + 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 (LI && VNI) { + LiveRange *Range = LI->getLiveRangeContaining(Start); + if (!Range || Range->valno != VNI) { + if (Kills) + Kills->push_back(Start); + continue; + } + if (Range->end < Stop) + Stop = Range->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() != LocNo || I.stop() != Start) + continue; + // 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) + continue; + + I.insert(Start, Stop, LocNo); + + // If we extended to the MBB end, propagate down the dominator tree. + if (!ToEnd) + continue; + const std::vector<MachineDomTreeNode*> &Children = + MDT.getNode(MBB)->getChildren(); + for (unsigned i = 0, e = Children.size(); i != e; ++i) { + MachineBasicBlock *MBB = Children[i]->getBlock(); + if (UVS.dominates(MBB)) + Todo.push_back(LIS.getMBBStartIdx(MBB)); + } + } while (!Todo.empty()); +} + +void +UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo, + const SmallVectorImpl<SlotIndex> &Kills, + SmallVectorImpl<std::pair<SlotIndex, unsigned> > &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 (MachineRegisterInfo::use_nodbg_iterator + UI = MRI.use_nodbg_begin(LI->reg), + UE = MRI.use_nodbg_end(); UI != UE; ++UI) { + // Copies of the full value. + if (UI.getOperand().getSubReg() || !UI->isCopy()) + continue; + MachineInstr *MI = &*UI; + 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) + 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; + + 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; + 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)); + I.insert(Idx, Idx.getNextSlot(), LocNo); + NewDefs.push_back(std::make_pair(Idx, LocNo)); + break; + } + } +} + +void +UserValue::computeIntervals(MachineRegisterInfo &MRI, + LiveIntervals &LIS, + MachineDominatorTree &MDT, + UserValueScopes &UVS) { + SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs; + + // Collect all defs to be extended (Skipping undefs). + for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) + if (I.value() != ~0u) + 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; + unsigned LocNo = Defs[i].second; + const MachineOperand &Loc = locations[LocNo]; + + // Register locations are constrained to where the register value is live. + if (Loc.isReg() && LIS.hasInterval(Loc.getReg())) { + LiveInterval *LI = &LIS.getInterval(Loc.getReg()); + const VNInfo *VNI = LI->getVNInfoAt(Idx); + SmallVector<SlotIndex, 16> Kills; + extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS); + addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS); + } else + extendDef(Idx, LocNo, 0, 0, 0, LIS, MDT, UVS); + } + + // Finally, erase all the undefs. + for (LocMap::iterator I = locInts.begin(); I.valid();) + if (I.value() == ~0u) + I.erase(); + else + ++I; +} + +void LDVImpl::computeIntervals() { + for (unsigned i = 0, e = userValues.size(); i != e; ++i) { + UserValueScopes UVS(userValues[i]->getDebugLoc(), LS); + userValues[i]->computeIntervals(MF->getRegInfo(), *LIS, *MDT, UVS); + userValues[i]->mapVirtRegs(this); + } +} + +bool LDVImpl::runOnMachineFunction(MachineFunction &mf) { + MF = &mf; + LIS = &pass.getAnalysis<LiveIntervals>(); + MDT = &pass.getAnalysis<MachineDominatorTree>(); + TRI = mf.getTarget().getRegisterInfo(); + clear(); + LS.initialize(mf); + DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: " + << ((Value*)mf.getFunction())->getName() + << " **********\n"); + + bool Changed = collectDebugValues(mf); + computeIntervals(); + DEBUG(print(dbgs())); + LS.releaseMemory(); + return Changed; +} + +bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) { + if (!EnableLDV) + 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); +} + +void UserValue:: +renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx, + const TargetRegisterInfo *TRI) { + for (unsigned i = locations.size(); i; --i) { + unsigned LocNo = i - 1; + MachineOperand &Loc = locations[LocNo]; + if (!Loc.isReg() || Loc.getReg() != OldReg) + continue; + if (TargetRegisterInfo::isPhysicalRegister(NewReg)) + Loc.substPhysReg(NewReg, *TRI); + else + Loc.substVirtReg(NewReg, SubIdx, *TRI); + coalesceLocation(LocNo); + } +} + +void LDVImpl:: +renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) { + UserValue *UV = lookupVirtReg(OldReg); + if (!UV) + return; + + if (TargetRegisterInfo::isVirtualRegister(NewReg)) + mapVirtReg(NewReg, UV); + virtRegToEqClass.erase(OldReg); + + do { + UV->renameRegister(OldReg, NewReg, SubIdx, TRI); + UV = UV->getNext(); + } while (UV); +} + +void LiveDebugVariables:: +renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx) { + if (pImpl) + static_cast<LDVImpl*>(pImpl)->renameRegister(OldReg, NewReg, SubIdx); +} + +//===----------------------------------------------------------------------===// +// Live Range Splitting +//===----------------------------------------------------------------------===// + +bool +UserValue::splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs) { + DEBUG({ + dbgs() << "Splitting Loc" << OldLocNo << '\t'; + print(dbgs(), 0); + }); + bool DidChange = false; + LocMap::iterator LocMapI; + LocMapI.setMap(locInts); + for (unsigned i = 0; i != NewRegs.size(); ++i) { + LiveInterval *LI = NewRegs[i]; + if (LI->empty()) + continue; + + // Don't allocate the new LocNo until it is needed. + unsigned NewLocNo = ~0u; + + // 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() == OldLocNo && LII->start < LocMapI.stop()) { + // Overlapping correct location. Allocate NewLocNo now. + if (NewLocNo == ~0u) { + 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(); + + // 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(NewLocNo); + + // Re-insert any removed OldLocNo ranges. + if (LStart < LocMapI.start()) { + LocMapI.insert(LStart, LocMapI.start(), OldLocNo); + ++LocMapI; + assert(LocMapI.valid() && "Unexpected coalescing"); + } + if (LStop > LocMapI.stop()) { + ++LocMapI; + LocMapI.insert(LII->end, LStop, OldLocNo); + --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()) { + unsigned v = LocMapI.value(); + if (v == OldLocNo) { + DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';' + << LocMapI.stop() << ")\n"); + LocMapI.erase(); + } else { + if (v > OldLocNo) + LocMapI.setValueUnchecked(v-1); + ++LocMapI; + } + } + + DEBUG({dbgs() << "Split result: \t"; print(dbgs(), 0);}); + return DidChange; +} + +bool +UserValue::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) { + 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); + } + return DidChange; +} + +void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) { + bool DidChange = false; + for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext()) + DidChange |= UV->splitRegister(OldReg, NewRegs); + + 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]->reg, UV); +} + +void LiveDebugVariables:: +splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) { + if (pImpl) + static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs); +} + +void +UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) { + // Iterate over locations in reverse makes it easier to handle coalescing. + for (unsigned i = locations.size(); i ; --i) { + unsigned LocNo = i-1; + MachineOperand &Loc = locations[LocNo]; + // Only virtual registers are rewritten. + if (!Loc.isReg() || !Loc.getReg() || + !TargetRegisterInfo::isVirtualRegister(Loc.getReg())) + continue; + 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) { + // FIXME: Translate SubIdx to a stackslot offset. + Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg)); + } else { + Loc.setReg(0); + Loc.setSubReg(0); + } + coalesceLocation(LocNo); + } +} + +/// findInsertLocation - 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->SkipPHIsAndLabels(MBB->begin()); + return I; + } + Idx = Idx.getPrevIndex(); + } + + // Don't insert anything after the first terminator, though. + return MI->isTerminator() ? MBB->getFirstTerminator() : + llvm::next(MachineBasicBlock::iterator(MI)); +} + +DebugLoc UserValue::findDebugLoc() { + DebugLoc D = dl; + dl = DebugLoc(); + return D; +} +void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, + unsigned LocNo, + LiveIntervals &LIS, + const TargetInstrInfo &TII) { + MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS); + MachineOperand &Loc = locations[LocNo]; + ++NumInsertedDebugValues; + + // Frame index locations may require a target callback. + if (Loc.isFI()) { + MachineInstr *MI = TII.emitFrameIndexDebugValue(*MBB->getParent(), + Loc.getIndex(), offset, variable, + findDebugLoc()); + if (MI) { + MBB->insert(I, MI); + return; + } + } + // This is not a frame index, or the target is happy with a standard FI. + BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE)) + .addOperand(Loc).addImm(offset).addMetadata(variable); +} + +void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS, + const TargetInstrInfo &TII) { + MachineFunction::iterator MFEnd = VRM->getMachineFunction().end(); + + for (LocMap::const_iterator I = locInts.begin(); I.valid();) { + SlotIndex Start = I.start(); + SlotIndex Stop = I.stop(); + unsigned LocNo = I.value(); + DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo); + MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start); + SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB); + + DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd); + insertDebugValue(MBB, Start, LocNo, LIS, TII); + // 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); + DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd); + insertDebugValue(MBB, Start, LocNo, LIS, TII); + } + DEBUG(dbgs() << '\n'); + if (MBB == MFEnd) + break; + + ++I; + } +} + +void LDVImpl::emitDebugValues(VirtRegMap *VRM) { + DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"); + const TargetInstrInfo *TII = MF->getTarget().getInstrInfo(); + for (unsigned i = 0, e = userValues.size(); i != e; ++i) { + DEBUG(userValues[i]->print(dbgs(), &MF->getTarget())); + userValues[i]->rewriteLocations(*VRM, *TRI); + userValues[i]->emitDebugValues(VRM, *LIS, *TII); + } +} + +void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) { + if (pImpl) + static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM); +} + + +#ifndef NDEBUG +void LiveDebugVariables::dump() { + if (pImpl) + static_cast<LDVImpl*>(pImpl)->print(dbgs()); +} +#endif + |
