//===----------------------------------------------------------------------===//
#include "LiveDebugVariables.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/CodeGen/VirtRegMap.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Value.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"
+#include "llvm/Target/TargetSubtargetInfo.h"
+
+#include <memory>
using namespace llvm;
+#define DEBUG_TYPE "livedebug"
+
+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) {
+LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID), pImpl(nullptr) {
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 a
+/// 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.
+ bool IsIndirect; ///< true if this is a register-indirect+offset value.
+ 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<unsigned> NewRegs,
+ LiveIntervals &LIS);
+
+public:
+ /// UserValue - Create a new UserValue.
+ UserValue(const MDNode *var, unsigned o, bool i, DebugLoc L,
+ LocMap::Allocator &alloc)
+ : variable(var), offset(o), IsIndirect(i), dl(L), leader(this),
+ next(nullptr), 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, bool indirect) const {
+ return Var == variable && Offset == offset && indirect == IsIndirect;
+ }
+
+ /// 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 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 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,
+ LiveRange *LR, 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, const TargetRegisterInfo &TRI,
+ LiveIntervals &LIS, MachineDominatorTree &MDT,
+ UserValueScopes &UVS);
+
+ /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
+ /// live. Returns true if any changes were made.
+ bool splitRegister(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
+ LiveIntervals &LIS);
+
+ /// rewriteLocations - Rewrite virtual register locations according to the
+ /// provided virtual register map.
+ void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
+
+ /// emitDebugValues - 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;
+
+ /// Whether emitDebugValues is called.
+ bool EmitDone;
+ /// Whether the machine function is modified during the pass.
+ bool ModifiedMF;
+
+ /// userValues - All allocated UserValue instances.
+ SmallVector<std::unique_ptr<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,
+ bool IsIndirect, 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), MF(nullptr), EmitDone(false), ModifiedMF(false) {}
+ bool runOnMachineFunction(MachineFunction &mf);
+
+ /// clear - Release all memory.
+ void clear() {
+ MF = nullptr;
+ userValues.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;
+ }
+
+ /// mapVirtReg - Map virtual register to an equivalence class.
+ void mapVirtReg(unsigned VirtReg, UserValue *EC);
+
+ /// splitRegister - Replace all references to OldReg with NewRegs.
+ void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
+
+ /// emitDebugValues - 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,
+ bool IsIndirect, DebugLoc DL) {
+ UserValue *&Leader = userVarMap[Var];
+ if (Leader) {
+ UserValue *UV = Leader->getLeader();
+ Leader = UV;
+ for (; UV; UV = UV->getNext())
+ if (UV->match(Var, Offset, IsIndirect))
+ return UV;
+ }
+
+ userValues.push_back(
+ make_unique<UserValue>(Var, Offset, IsIndirect, 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() != 3 ||
+ !(MI->getOperand(1).isReg() || MI->getOperand(1).isImm()) ||
+ !MI->getOperand(2).isMetadata()) {
+ DEBUG(dbgs() << "Can't handle " << *MI);
+ return false;
+ }
+
+ // Get or create the UserValue for (variable,offset).
+ bool IsIndirect = MI->isIndirectDebugValue();
+ unsigned Offset = IsIndirect ? MI->getOperand(1).getImm() : 0;
+ const MDNode *Var = MI->getOperand(2).getMetadata();
+ //here.
+ UserValue *UV = getUserValue(Var, Offset, IsIndirect, 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(std::prev(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,
+ LiveRange *LR, 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 (LR && VNI) {
+ LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
+ if (!Segment || Segment->valno != VNI) {
+ if (Kills)
+ Kills->push_back(Start);
+ continue;
+ }
+ 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() != 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 (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)
+ 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,
+ const TargetRegisterInfo &TRI,
+ 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];
+
+ if (!Loc.isReg()) {
+ extendDef(Idx, LocNo, nullptr, nullptr, nullptr, LIS, MDT, UVS);
+ continue;
+ }
+
+ // Register locations are constrained to where the register value is live.
+ if (TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
+ LiveInterval *LI = nullptr;
+ const VNInfo *VNI = nullptr;
+ if (LIS.hasInterval(Loc.getReg())) {
+ LI = &LIS.getInterval(Loc.getReg());
+ VNI = LI->getVNInfoAt(Idx);
+ }
+ SmallVector<SlotIndex, 16> Kills;
+ extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS);
+ if (LI)
+ addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
+ continue;
+ }
+
+ // For physregs, use the live range of the first regunit as a guide.
+ unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
+ LiveRange *LR = &LIS.getRegUnit(Unit);
+ const VNInfo *VNI = LR->getVNInfoAt(Idx);
+ // Don't track copies from physregs, it is too expensive.
+ extendDef(Idx, LocNo, LR, VNI, nullptr, 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(), *TRI, *LIS, *MDT, UVS);
+ userValues[i]->mapVirtRegs(this);
+ }
+}
+
+bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
+ clear();
+ MF = &mf;
+ LIS = &pass.getAnalysis<LiveIntervals>();
+ MDT = &pass.getAnalysis<MachineDominatorTree>();
+ TRI = mf.getSubtarget().getRegisterInfo();
+ LS.initialize(mf);
+ DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
+ << mf.getName() << " **********\n");
+
+ bool Changed = collectDebugValues(mf);
+ computeIntervals();
+ 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) {
- return false;
+ if (!EnableLDV)
+ return false;
+ if (!FunctionDIs.count(mf.getFunction())) {
+ 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) {
+ 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 = ~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(), 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 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() :
+ std::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;
+
+ if (Loc.isReg())
+ BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
+ IsIndirect, Loc.getReg(), offset, variable);
+ else
+ 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");
+ if (!MF)
+ return;
+ const TargetInstrInfo *TII = MF->getSubtarget().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);
+ }
+ EmitDone = true;
+}
+
+void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
+ if (pImpl)
+ static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
+}
+
+bool LiveDebugVariables::doInitialization(Module &M) {
+ FunctionDIs = makeSubprogramMap(M);
+ return Pass::doInitialization(M);
+}
+
+#ifndef NDEBUG
+void LiveDebugVariables::dump() {
+ if (pImpl)
+ static_cast<LDVImpl*>(pImpl)->print(dbgs());
}
+#endif
projects / oota-llvm.git / blobdiff