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Diffstat (limited to 'contrib/llvm/lib/CodeGen/LiveDebugValues.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/LiveDebugValues.cpp | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/LiveDebugValues.cpp b/contrib/llvm/lib/CodeGen/LiveDebugValues.cpp new file mode 100644 index 0000000..98d30b9 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/LiveDebugValues.cpp @@ -0,0 +1,405 @@ +//===------ LiveDebugValues.cpp - Tracking Debug Value MIs ----------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +/// +/// This pass implements a data flow analysis that propagates debug location +/// information by inserting additional DBG_VALUE instructions into the machine +/// instruction stream. The pass internally builds debug location liveness +/// ranges to determine the points where additional DBG_VALUEs need to be +/// inserted. +/// +/// This is a separate pass from DbgValueHistoryCalculator to facilitate +/// testing and improve modularity. +/// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/Statistic.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetSubtargetInfo.h" +#include <deque> +#include <list> + +using namespace llvm; + +#define DEBUG_TYPE "live-debug-values" + +STATISTIC(NumInserted, "Number of DBG_VALUE instructions inserted"); + +namespace { + +class LiveDebugValues : public MachineFunctionPass { + +private: + const TargetRegisterInfo *TRI; + const TargetInstrInfo *TII; + + typedef std::pair<const DILocalVariable *, const DILocation *> + InlinedVariable; + + /// A potentially inlined instance of a variable. + struct DebugVariable { + const DILocalVariable *Var; + const DILocation *InlinedAt; + + DebugVariable(const DILocalVariable *_var, const DILocation *_inlinedAt) + : Var(_var), InlinedAt(_inlinedAt) {} + + bool operator==(const DebugVariable &DV) const { + return (Var == DV.Var) && (InlinedAt == DV.InlinedAt); + } + }; + + /// Member variables and functions for Range Extension across basic blocks. + struct VarLoc { + DebugVariable Var; + const MachineInstr *MI; // MachineInstr should be a DBG_VALUE instr. + + VarLoc(DebugVariable _var, const MachineInstr *_mi) : Var(_var), MI(_mi) {} + + bool operator==(const VarLoc &V) const; + }; + + typedef std::list<VarLoc> VarLocList; + typedef SmallDenseMap<const MachineBasicBlock *, VarLocList> VarLocInMBB; + + bool OLChanged; // OutgoingLocs got changed for this bb. + bool MBBJoined; // The MBB was joined. + + void transferDebugValue(MachineInstr &MI, VarLocList &OpenRanges); + void transferRegisterDef(MachineInstr &MI, VarLocList &OpenRanges); + void transferTerminatorInst(MachineInstr &MI, VarLocList &OpenRanges, + VarLocInMBB &OutLocs); + void transfer(MachineInstr &MI, VarLocList &OpenRanges, VarLocInMBB &OutLocs); + + void join(MachineBasicBlock &MBB, VarLocInMBB &OutLocs, VarLocInMBB &InLocs); + + bool ExtendRanges(MachineFunction &MF); + +public: + static char ID; + + /// Default construct and initialize the pass. + LiveDebugValues(); + + /// Tell the pass manager which passes we depend on and what + /// information we preserve. + void getAnalysisUsage(AnalysisUsage &AU) const override; + + /// Print to ostream with a message. + void printVarLocInMBB(const VarLocInMBB &V, const char *msg, + raw_ostream &Out) const; + + /// Calculate the liveness information for the given machine function. + bool runOnMachineFunction(MachineFunction &MF) override; +}; +} // namespace + +//===----------------------------------------------------------------------===// +// Implementation +//===----------------------------------------------------------------------===// + +char LiveDebugValues::ID = 0; +char &llvm::LiveDebugValuesID = LiveDebugValues::ID; +INITIALIZE_PASS(LiveDebugValues, "livedebugvalues", "Live DEBUG_VALUE analysis", + false, false) + +/// Default construct and initialize the pass. +LiveDebugValues::LiveDebugValues() : MachineFunctionPass(ID) { + initializeLiveDebugValuesPass(*PassRegistry::getPassRegistry()); +} + +/// Tell the pass manager which passes we depend on and what information we +/// preserve. +void LiveDebugValues::getAnalysisUsage(AnalysisUsage &AU) const { + MachineFunctionPass::getAnalysisUsage(AU); +} + +// \brief If @MI is a DBG_VALUE with debug value described by a defined +// register, returns the number of this register. In the other case, returns 0. +static unsigned isDescribedByReg(const MachineInstr &MI) { + assert(MI.isDebugValue()); + assert(MI.getNumOperands() == 4); + // If location of variable is described using a register (directly or + // indirecltly), this register is always a first operand. + return MI.getOperand(0).isReg() ? MI.getOperand(0).getReg() : 0; +} + +// \brief This function takes two DBG_VALUE instructions and returns true +// if their offsets are equal; otherwise returns false. +static bool areOffsetsEqual(const MachineInstr &MI1, const MachineInstr &MI2) { + assert(MI1.isDebugValue()); + assert(MI1.getNumOperands() == 4); + + assert(MI2.isDebugValue()); + assert(MI2.getNumOperands() == 4); + + if (!MI1.isIndirectDebugValue() && !MI2.isIndirectDebugValue()) + return true; + + // Check if both MIs are indirect and they are equal. + if (MI1.isIndirectDebugValue() && MI2.isIndirectDebugValue()) + return MI1.getOperand(1).getImm() == MI2.getOperand(1).getImm(); + + return false; +} + +//===----------------------------------------------------------------------===// +// Debug Range Extension Implementation +//===----------------------------------------------------------------------===// + +void LiveDebugValues::printVarLocInMBB(const VarLocInMBB &V, const char *msg, + raw_ostream &Out) const { + Out << "Printing " << msg << ":\n"; + for (const auto &L : V) { + Out << "MBB: " << L.first->getName() << ":\n"; + for (const auto &VLL : L.second) { + Out << " Var: " << VLL.Var.Var->getName(); + Out << " MI: "; + (*VLL.MI).dump(); + Out << "\n"; + } + } + Out << "\n"; +} + +bool LiveDebugValues::VarLoc::operator==(const VarLoc &V) const { + return (Var == V.Var) && (isDescribedByReg(*MI) == isDescribedByReg(*V.MI)) && + (areOffsetsEqual(*MI, *V.MI)); +} + +/// End all previous ranges related to @MI and start a new range from @MI +/// if it is a DBG_VALUE instr. +void LiveDebugValues::transferDebugValue(MachineInstr &MI, + VarLocList &OpenRanges) { + if (!MI.isDebugValue()) + return; + const DILocalVariable *RawVar = MI.getDebugVariable(); + assert(RawVar->isValidLocationForIntrinsic(MI.getDebugLoc()) && + "Expected inlined-at fields to agree"); + DebugVariable Var(RawVar, MI.getDebugLoc()->getInlinedAt()); + + // End all previous ranges of Var. + OpenRanges.erase( + std::remove_if(OpenRanges.begin(), OpenRanges.end(), + [&](const VarLoc &V) { return (Var == V.Var); }), + OpenRanges.end()); + + // Add Var to OpenRanges from this DBG_VALUE. + // TODO: Currently handles DBG_VALUE which has only reg as location. + if (isDescribedByReg(MI)) { + VarLoc V(Var, &MI); + OpenRanges.push_back(std::move(V)); + } +} + +/// A definition of a register may mark the end of a range. +void LiveDebugValues::transferRegisterDef(MachineInstr &MI, + VarLocList &OpenRanges) { + for (const MachineOperand &MO : MI.operands()) { + if (!(MO.isReg() && MO.isDef() && MO.getReg() && + TRI->isPhysicalRegister(MO.getReg()))) + continue; + // Remove ranges of all aliased registers. + for (MCRegAliasIterator RAI(MO.getReg(), TRI, true); RAI.isValid(); ++RAI) + OpenRanges.erase(std::remove_if(OpenRanges.begin(), OpenRanges.end(), + [&](const VarLoc &V) { + return (*RAI == + isDescribedByReg(*V.MI)); + }), + OpenRanges.end()); + } +} + +/// Terminate all open ranges at the end of the current basic block. +void LiveDebugValues::transferTerminatorInst(MachineInstr &MI, + VarLocList &OpenRanges, + VarLocInMBB &OutLocs) { + const MachineBasicBlock *CurMBB = MI.getParent(); + if (!(MI.isTerminator() || (&MI == &CurMBB->instr_back()))) + return; + + if (OpenRanges.empty()) + return; + + if (OutLocs.find(CurMBB) == OutLocs.end()) { + // Create space for new Outgoing locs entries. + VarLocList VLL; + OutLocs.insert(std::make_pair(CurMBB, std::move(VLL))); + } + auto OL = OutLocs.find(CurMBB); + assert(OL != OutLocs.end()); + VarLocList &VLL = OL->second; + + for (auto OR : OpenRanges) { + // Copy OpenRanges to OutLocs, if not already present. + assert(OR.MI->isDebugValue()); + DEBUG(dbgs() << "Add to OutLocs: "; OR.MI->dump();); + if (std::find_if(VLL.begin(), VLL.end(), + [&](const VarLoc &V) { return (OR == V); }) == VLL.end()) { + VLL.push_back(std::move(OR)); + OLChanged = true; + } + } + OpenRanges.clear(); +} + +/// This routine creates OpenRanges and OutLocs. +void LiveDebugValues::transfer(MachineInstr &MI, VarLocList &OpenRanges, + VarLocInMBB &OutLocs) { + transferDebugValue(MI, OpenRanges); + transferRegisterDef(MI, OpenRanges); + transferTerminatorInst(MI, OpenRanges, OutLocs); +} + +/// This routine joins the analysis results of all incoming edges in @MBB by +/// inserting a new DBG_VALUE instruction at the start of the @MBB - if the same +/// source variable in all the predecessors of @MBB reside in the same location. +void LiveDebugValues::join(MachineBasicBlock &MBB, VarLocInMBB &OutLocs, + VarLocInMBB &InLocs) { + DEBUG(dbgs() << "join MBB: " << MBB.getName() << "\n"); + + MBBJoined = false; + + VarLocList InLocsT; // Temporary incoming locations. + + // For all predecessors of this MBB, find the set of VarLocs that can be + // joined. + for (auto p : MBB.predecessors()) { + auto OL = OutLocs.find(p); + // Join is null in case of empty OutLocs from any of the pred. + if (OL == OutLocs.end()) + return; + + // Just copy over the Out locs to incoming locs for the first predecessor. + if (p == *MBB.pred_begin()) { + InLocsT = OL->second; + continue; + } + + // Join with this predecessor. + VarLocList &VLL = OL->second; + InLocsT.erase(std::remove_if(InLocsT.begin(), InLocsT.end(), + [&](VarLoc &ILT) { + return (std::find_if(VLL.begin(), VLL.end(), + [&](const VarLoc &V) { + return (ILT == V); + }) == VLL.end()); + }), + InLocsT.end()); + } + + if (InLocsT.empty()) + return; + + if (InLocs.find(&MBB) == InLocs.end()) { + // Create space for new Incoming locs entries. + VarLocList VLL; + InLocs.insert(std::make_pair(&MBB, std::move(VLL))); + } + auto IL = InLocs.find(&MBB); + assert(IL != InLocs.end()); + VarLocList &ILL = IL->second; + + // Insert DBG_VALUE instructions, if not already inserted. + for (auto ILT : InLocsT) { + if (std::find_if(ILL.begin(), ILL.end(), [&](const VarLoc &I) { + return (ILT == I); + }) == ILL.end()) { + // This VarLoc is not found in InLocs i.e. it is not yet inserted. So, a + // new range is started for the var from the mbb's beginning by inserting + // a new DBG_VALUE. transfer() will end this range however appropriate. + const MachineInstr *DMI = ILT.MI; + MachineInstr *MI = + BuildMI(MBB, MBB.instr_begin(), DMI->getDebugLoc(), DMI->getDesc(), + DMI->isIndirectDebugValue(), DMI->getOperand(0).getReg(), 0, + DMI->getDebugVariable(), DMI->getDebugExpression()); + if (DMI->isIndirectDebugValue()) + MI->getOperand(1).setImm(DMI->getOperand(1).getImm()); + DEBUG(dbgs() << "Inserted: "; MI->dump();); + ++NumInserted; + MBBJoined = true; // rerun transfer(). + + VarLoc V(ILT.Var, MI); + ILL.push_back(std::move(V)); + } + } +} + +/// Calculate the liveness information for the given machine function and +/// extend ranges across basic blocks. +bool LiveDebugValues::ExtendRanges(MachineFunction &MF) { + + DEBUG(dbgs() << "\nDebug Range Extension\n"); + + bool Changed = false; + OLChanged = MBBJoined = false; + + VarLocList OpenRanges; // Ranges that are open until end of bb. + VarLocInMBB OutLocs; // Ranges that exist beyond bb. + VarLocInMBB InLocs; // Ranges that are incoming after joining. + + std::deque<MachineBasicBlock *> BBWorklist; + + // Initialize every mbb with OutLocs. + for (auto &MBB : MF) + for (auto &MI : MBB) + transfer(MI, OpenRanges, OutLocs); + DEBUG(printVarLocInMBB(OutLocs, "OutLocs after initialization", dbgs())); + + // Construct a worklist of MBBs. + for (auto &MBB : MF) + BBWorklist.push_back(&MBB); + + // Perform join() and transfer() using the worklist until the ranges converge + // Ranges have converged when the worklist is empty. + while (!BBWorklist.empty()) { + MachineBasicBlock *MBB = BBWorklist.front(); + BBWorklist.pop_front(); + + join(*MBB, OutLocs, InLocs); + + if (MBBJoined) { + Changed = true; + for (auto &MI : *MBB) + transfer(MI, OpenRanges, OutLocs); + DEBUG(printVarLocInMBB(OutLocs, "OutLocs after propagating", dbgs())); + DEBUG(printVarLocInMBB(InLocs, "InLocs after propagating", dbgs())); + + if (OLChanged) { + OLChanged = false; + for (auto s : MBB->successors()) + if (std::find(BBWorklist.begin(), BBWorklist.end(), s) == + BBWorklist.end()) // add if not already present. + BBWorklist.push_back(s); + } + } + } + DEBUG(printVarLocInMBB(OutLocs, "Final OutLocs", dbgs())); + DEBUG(printVarLocInMBB(InLocs, "Final InLocs", dbgs())); + return Changed; +} + +bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) { + TRI = MF.getSubtarget().getRegisterInfo(); + TII = MF.getSubtarget().getInstrInfo(); + + bool Changed = false; + + Changed |= ExtendRanges(MF); + + return Changed; +} |
