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Diffstat (limited to 'contrib/llvm/lib/CodeGen/MachineVerifier.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/MachineVerifier.cpp | 888 |
1 files changed, 888 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/MachineVerifier.cpp b/contrib/llvm/lib/CodeGen/MachineVerifier.cpp new file mode 100644 index 0000000..8baf01c --- /dev/null +++ b/contrib/llvm/lib/CodeGen/MachineVerifier.cpp @@ -0,0 +1,888 @@ +//===-- MachineVerifier.cpp - Machine Code Verifier -------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Pass to verify generated machine code. The following is checked: +// +// Operand counts: All explicit operands must be present. +// +// Register classes: All physical and virtual register operands must be +// compatible with the register class required by the instruction descriptor. +// +// Register live intervals: Registers must be defined only once, and must be +// defined before use. +// +// The machine code verifier is enabled from LLVMTargetMachine.cpp with the +// command-line option -verify-machineinstrs, or by defining the environment +// variable LLVM_VERIFY_MACHINEINSTRS to the name of a file that will receive +// the verifier errors. +//===----------------------------------------------------------------------===// + +#include "llvm/Function.h" +#include "llvm/CodeGen/LiveVariables.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineMemOperand.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/SetOperations.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" +using namespace llvm; + +namespace { + struct MachineVerifier { + + MachineVerifier(Pass *pass, bool allowDoubleDefs) : + PASS(pass), + allowVirtDoubleDefs(allowDoubleDefs), + allowPhysDoubleDefs(true), + OutFileName(getenv("LLVM_VERIFY_MACHINEINSTRS")) + {} + + bool runOnMachineFunction(MachineFunction &MF); + + Pass *const PASS; + const bool allowVirtDoubleDefs; + const bool allowPhysDoubleDefs; + + const char *const OutFileName; + raw_ostream *OS; + const MachineFunction *MF; + const TargetMachine *TM; + const TargetRegisterInfo *TRI; + const MachineRegisterInfo *MRI; + + unsigned foundErrors; + + typedef SmallVector<unsigned, 16> RegVector; + typedef DenseSet<unsigned> RegSet; + typedef DenseMap<unsigned, const MachineInstr*> RegMap; + + BitVector regsReserved; + RegSet regsLive; + RegVector regsDefined, regsDead, regsKilled; + RegSet regsLiveInButUnused; + + // Add Reg and any sub-registers to RV + void addRegWithSubRegs(RegVector &RV, unsigned Reg) { + RV.push_back(Reg); + if (TargetRegisterInfo::isPhysicalRegister(Reg)) + for (const unsigned *R = TRI->getSubRegisters(Reg); *R; R++) + RV.push_back(*R); + } + + struct BBInfo { + // Is this MBB reachable from the MF entry point? + bool reachable; + + // Vregs that must be live in because they are used without being + // defined. Map value is the user. + RegMap vregsLiveIn; + + // Vregs that must be dead in because they are defined without being + // killed first. Map value is the defining instruction. + RegMap vregsDeadIn; + + // Regs killed in MBB. They may be defined again, and will then be in both + // regsKilled and regsLiveOut. + RegSet regsKilled; + + // Regs defined in MBB and live out. Note that vregs passing through may + // be live out without being mentioned here. + RegSet regsLiveOut; + + // Vregs that pass through MBB untouched. This set is disjoint from + // regsKilled and regsLiveOut. + RegSet vregsPassed; + + // Vregs that must pass through MBB because they are needed by a successor + // block. This set is disjoint from regsLiveOut. + RegSet vregsRequired; + + BBInfo() : reachable(false) {} + + // Add register to vregsPassed if it belongs there. Return true if + // anything changed. + bool addPassed(unsigned Reg) { + if (!TargetRegisterInfo::isVirtualRegister(Reg)) + return false; + if (regsKilled.count(Reg) || regsLiveOut.count(Reg)) + return false; + return vregsPassed.insert(Reg).second; + } + + // Same for a full set. + bool addPassed(const RegSet &RS) { + bool changed = false; + for (RegSet::const_iterator I = RS.begin(), E = RS.end(); I != E; ++I) + if (addPassed(*I)) + changed = true; + return changed; + } + + // Add register to vregsRequired if it belongs there. Return true if + // anything changed. + bool addRequired(unsigned Reg) { + if (!TargetRegisterInfo::isVirtualRegister(Reg)) + return false; + if (regsLiveOut.count(Reg)) + return false; + return vregsRequired.insert(Reg).second; + } + + // Same for a full set. + bool addRequired(const RegSet &RS) { + bool changed = false; + for (RegSet::const_iterator I = RS.begin(), E = RS.end(); I != E; ++I) + if (addRequired(*I)) + changed = true; + return changed; + } + + // Same for a full map. + bool addRequired(const RegMap &RM) { + bool changed = false; + for (RegMap::const_iterator I = RM.begin(), E = RM.end(); I != E; ++I) + if (addRequired(I->first)) + changed = true; + return changed; + } + + // Live-out registers are either in regsLiveOut or vregsPassed. + bool isLiveOut(unsigned Reg) const { + return regsLiveOut.count(Reg) || vregsPassed.count(Reg); + } + }; + + // Extra register info per MBB. + DenseMap<const MachineBasicBlock*, BBInfo> MBBInfoMap; + + bool isReserved(unsigned Reg) { + return Reg < regsReserved.size() && regsReserved.test(Reg); + } + + // Analysis information if available + LiveVariables *LiveVars; + + void visitMachineFunctionBefore(); + void visitMachineBasicBlockBefore(const MachineBasicBlock *MBB); + void visitMachineInstrBefore(const MachineInstr *MI); + void visitMachineOperand(const MachineOperand *MO, unsigned MONum); + void visitMachineInstrAfter(const MachineInstr *MI); + void visitMachineBasicBlockAfter(const MachineBasicBlock *MBB); + void visitMachineFunctionAfter(); + + void report(const char *msg, const MachineFunction *MF); + void report(const char *msg, const MachineBasicBlock *MBB); + void report(const char *msg, const MachineInstr *MI); + void report(const char *msg, const MachineOperand *MO, unsigned MONum); + + void markReachable(const MachineBasicBlock *MBB); + void calcRegsPassed(); + void checkPHIOps(const MachineBasicBlock *MBB); + + void calcRegsRequired(); + void verifyLiveVariables(); + }; + + struct MachineVerifierPass : public MachineFunctionPass { + static char ID; // Pass ID, replacement for typeid + bool AllowDoubleDefs; + + explicit MachineVerifierPass(bool allowDoubleDefs = false) + : MachineFunctionPass(&ID), + AllowDoubleDefs(allowDoubleDefs) {} + + void getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + MachineFunctionPass::getAnalysisUsage(AU); + } + + bool runOnMachineFunction(MachineFunction &MF) { + MF.verify(this, AllowDoubleDefs); + return false; + } + }; + +} + +char MachineVerifierPass::ID = 0; +static RegisterPass<MachineVerifierPass> +MachineVer("machineverifier", "Verify generated machine code"); +static const PassInfo *const MachineVerifyID = &MachineVer; + +FunctionPass *llvm::createMachineVerifierPass(bool allowPhysDoubleDefs) { + return new MachineVerifierPass(allowPhysDoubleDefs); +} + +void MachineFunction::verify(Pass *p, bool allowDoubleDefs) const { + MachineVerifier(p, allowDoubleDefs) + .runOnMachineFunction(const_cast<MachineFunction&>(*this)); +} + +bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) { + raw_ostream *OutFile = 0; + if (OutFileName) { + std::string ErrorInfo; + OutFile = new raw_fd_ostream(OutFileName, ErrorInfo, + raw_fd_ostream::F_Append); + if (!ErrorInfo.empty()) { + errs() << "Error opening '" << OutFileName << "': " << ErrorInfo << '\n'; + exit(1); + } + + OS = OutFile; + } else { + OS = &errs(); + } + + foundErrors = 0; + + this->MF = &MF; + TM = &MF.getTarget(); + TRI = TM->getRegisterInfo(); + MRI = &MF.getRegInfo(); + + if (PASS) { + LiveVars = PASS->getAnalysisIfAvailable<LiveVariables>(); + } else { + LiveVars = NULL; + } + + visitMachineFunctionBefore(); + for (MachineFunction::const_iterator MFI = MF.begin(), MFE = MF.end(); + MFI!=MFE; ++MFI) { + visitMachineBasicBlockBefore(MFI); + for (MachineBasicBlock::const_iterator MBBI = MFI->begin(), + MBBE = MFI->end(); MBBI != MBBE; ++MBBI) { + visitMachineInstrBefore(MBBI); + for (unsigned I = 0, E = MBBI->getNumOperands(); I != E; ++I) + visitMachineOperand(&MBBI->getOperand(I), I); + visitMachineInstrAfter(MBBI); + } + visitMachineBasicBlockAfter(MFI); + } + visitMachineFunctionAfter(); + + if (OutFile) + delete OutFile; + else if (foundErrors) + report_fatal_error("Found "+Twine(foundErrors)+" machine code errors."); + + // Clean up. + regsLive.clear(); + regsDefined.clear(); + regsDead.clear(); + regsKilled.clear(); + regsLiveInButUnused.clear(); + MBBInfoMap.clear(); + + return false; // no changes +} + +void MachineVerifier::report(const char *msg, const MachineFunction *MF) { + assert(MF); + *OS << '\n'; + if (!foundErrors++) + MF->print(*OS); + *OS << "*** Bad machine code: " << msg << " ***\n" + << "- function: " << MF->getFunction()->getNameStr() << "\n"; +} + +void MachineVerifier::report(const char *msg, const MachineBasicBlock *MBB) { + assert(MBB); + report(msg, MBB->getParent()); + *OS << "- basic block: " << MBB->getName() + << " " << (void*)MBB + << " (BB#" << MBB->getNumber() << ")\n"; +} + +void MachineVerifier::report(const char *msg, const MachineInstr *MI) { + assert(MI); + report(msg, MI->getParent()); + *OS << "- instruction: "; + MI->print(*OS, TM); +} + +void MachineVerifier::report(const char *msg, + const MachineOperand *MO, unsigned MONum) { + assert(MO); + report(msg, MO->getParent()); + *OS << "- operand " << MONum << ": "; + MO->print(*OS, TM); + *OS << "\n"; +} + +void MachineVerifier::markReachable(const MachineBasicBlock *MBB) { + BBInfo &MInfo = MBBInfoMap[MBB]; + if (!MInfo.reachable) { + MInfo.reachable = true; + for (MachineBasicBlock::const_succ_iterator SuI = MBB->succ_begin(), + SuE = MBB->succ_end(); SuI != SuE; ++SuI) + markReachable(*SuI); + } +} + +void MachineVerifier::visitMachineFunctionBefore() { + regsReserved = TRI->getReservedRegs(*MF); + + // A sub-register of a reserved register is also reserved + for (int Reg = regsReserved.find_first(); Reg>=0; + Reg = regsReserved.find_next(Reg)) { + for (const unsigned *Sub = TRI->getSubRegisters(Reg); *Sub; ++Sub) { + // FIXME: This should probably be: + // assert(regsReserved.test(*Sub) && "Non-reserved sub-register"); + regsReserved.set(*Sub); + } + } + markReachable(&MF->front()); +} + +// Does iterator point to a and b as the first two elements? +static bool matchPair(MachineBasicBlock::const_succ_iterator i, + const MachineBasicBlock *a, const MachineBasicBlock *b) { + if (*i == a) + return *++i == b; + if (*i == b) + return *++i == a; + return false; +} + +void +MachineVerifier::visitMachineBasicBlockBefore(const MachineBasicBlock *MBB) { + const TargetInstrInfo *TII = MF->getTarget().getInstrInfo(); + + // Call AnalyzeBranch. If it succeeds, there several more conditions to check. + MachineBasicBlock *TBB = 0, *FBB = 0; + SmallVector<MachineOperand, 4> Cond; + if (!TII->AnalyzeBranch(*const_cast<MachineBasicBlock *>(MBB), + TBB, FBB, Cond)) { + // Ok, AnalyzeBranch thinks it knows what's going on with this block. Let's + // check whether its answers match up with reality. + if (!TBB && !FBB) { + // Block falls through to its successor. + MachineFunction::const_iterator MBBI = MBB; + ++MBBI; + if (MBBI == MF->end()) { + // It's possible that the block legitimately ends with a noreturn + // call or an unreachable, in which case it won't actually fall + // out the bottom of the function. + } else if (MBB->succ_empty()) { + // It's possible that the block legitimately ends with a noreturn + // call or an unreachable, in which case it won't actuall fall + // out of the block. + } else if (MBB->succ_size() != 1) { + report("MBB exits via unconditional fall-through but doesn't have " + "exactly one CFG successor!", MBB); + } else if (MBB->succ_begin()[0] != MBBI) { + report("MBB exits via unconditional fall-through but its successor " + "differs from its CFG successor!", MBB); + } + if (!MBB->empty() && MBB->back().getDesc().isBarrier()) { + report("MBB exits via unconditional fall-through but ends with a " + "barrier instruction!", MBB); + } + if (!Cond.empty()) { + report("MBB exits via unconditional fall-through but has a condition!", + MBB); + } + } else if (TBB && !FBB && Cond.empty()) { + // Block unconditionally branches somewhere. + if (MBB->succ_size() != 1) { + report("MBB exits via unconditional branch but doesn't have " + "exactly one CFG successor!", MBB); + } else if (MBB->succ_begin()[0] != TBB) { + report("MBB exits via unconditional branch but the CFG " + "successor doesn't match the actual successor!", MBB); + } + if (MBB->empty()) { + report("MBB exits via unconditional branch but doesn't contain " + "any instructions!", MBB); + } else if (!MBB->back().getDesc().isBarrier()) { + report("MBB exits via unconditional branch but doesn't end with a " + "barrier instruction!", MBB); + } else if (!MBB->back().getDesc().isTerminator()) { + report("MBB exits via unconditional branch but the branch isn't a " + "terminator instruction!", MBB); + } + } else if (TBB && !FBB && !Cond.empty()) { + // Block conditionally branches somewhere, otherwise falls through. + MachineFunction::const_iterator MBBI = MBB; + ++MBBI; + if (MBBI == MF->end()) { + report("MBB conditionally falls through out of function!", MBB); + } if (MBB->succ_size() != 2) { + report("MBB exits via conditional branch/fall-through but doesn't have " + "exactly two CFG successors!", MBB); + } else if (!matchPair(MBB->succ_begin(), TBB, MBBI)) { + report("MBB exits via conditional branch/fall-through but the CFG " + "successors don't match the actual successors!", MBB); + } + if (MBB->empty()) { + report("MBB exits via conditional branch/fall-through but doesn't " + "contain any instructions!", MBB); + } else if (MBB->back().getDesc().isBarrier()) { + report("MBB exits via conditional branch/fall-through but ends with a " + "barrier instruction!", MBB); + } else if (!MBB->back().getDesc().isTerminator()) { + report("MBB exits via conditional branch/fall-through but the branch " + "isn't a terminator instruction!", MBB); + } + } else if (TBB && FBB) { + // Block conditionally branches somewhere, otherwise branches + // somewhere else. + if (MBB->succ_size() != 2) { + report("MBB exits via conditional branch/branch but doesn't have " + "exactly two CFG successors!", MBB); + } else if (!matchPair(MBB->succ_begin(), TBB, FBB)) { + report("MBB exits via conditional branch/branch but the CFG " + "successors don't match the actual successors!", MBB); + } + if (MBB->empty()) { + report("MBB exits via conditional branch/branch but doesn't " + "contain any instructions!", MBB); + } else if (!MBB->back().getDesc().isBarrier()) { + report("MBB exits via conditional branch/branch but doesn't end with a " + "barrier instruction!", MBB); + } else if (!MBB->back().getDesc().isTerminator()) { + report("MBB exits via conditional branch/branch but the branch " + "isn't a terminator instruction!", MBB); + } + if (Cond.empty()) { + report("MBB exits via conditinal branch/branch but there's no " + "condition!", MBB); + } + } else { + report("AnalyzeBranch returned invalid data!", MBB); + } + } + + regsLive.clear(); + for (MachineBasicBlock::livein_iterator I = MBB->livein_begin(), + E = MBB->livein_end(); I != E; ++I) { + if (!TargetRegisterInfo::isPhysicalRegister(*I)) { + report("MBB live-in list contains non-physical register", MBB); + continue; + } + regsLive.insert(*I); + for (const unsigned *R = TRI->getSubRegisters(*I); *R; R++) + regsLive.insert(*R); + } + regsLiveInButUnused = regsLive; + + const MachineFrameInfo *MFI = MF->getFrameInfo(); + assert(MFI && "Function has no frame info"); + BitVector PR = MFI->getPristineRegs(MBB); + for (int I = PR.find_first(); I>0; I = PR.find_next(I)) { + regsLive.insert(I); + for (const unsigned *R = TRI->getSubRegisters(I); *R; R++) + regsLive.insert(*R); + } + + regsKilled.clear(); + regsDefined.clear(); +} + +void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) { + const TargetInstrDesc &TI = MI->getDesc(); + if (MI->getNumOperands() < TI.getNumOperands()) { + report("Too few operands", MI); + *OS << TI.getNumOperands() << " operands expected, but " + << MI->getNumExplicitOperands() << " given.\n"; + } + + // Check the MachineMemOperands for basic consistency. + for (MachineInstr::mmo_iterator I = MI->memoperands_begin(), + E = MI->memoperands_end(); I != E; ++I) { + if ((*I)->isLoad() && !TI.mayLoad()) + report("Missing mayLoad flag", MI); + if ((*I)->isStore() && !TI.mayStore()) + report("Missing mayStore flag", MI); + } +} + +void +MachineVerifier::visitMachineOperand(const MachineOperand *MO, unsigned MONum) { + const MachineInstr *MI = MO->getParent(); + const TargetInstrDesc &TI = MI->getDesc(); + + // The first TI.NumDefs operands must be explicit register defines + if (MONum < TI.getNumDefs()) { + if (!MO->isReg()) + report("Explicit definition must be a register", MO, MONum); + else if (!MO->isDef()) + report("Explicit definition marked as use", MO, MONum); + else if (MO->isImplicit()) + report("Explicit definition marked as implicit", MO, MONum); + } else if (MONum < TI.getNumOperands()) { + if (MO->isReg()) { + if (MO->isDef()) + report("Explicit operand marked as def", MO, MONum); + if (MO->isImplicit()) + report("Explicit operand marked as implicit", MO, MONum); + } + } else { + // ARM adds %reg0 operands to indicate predicates. We'll allow that. + if (MO->isReg() && !MO->isImplicit() && !TI.isVariadic() && MO->getReg()) + report("Extra explicit operand on non-variadic instruction", MO, MONum); + } + + switch (MO->getType()) { + case MachineOperand::MO_Register: { + const unsigned Reg = MO->getReg(); + if (!Reg) + return; + + // Check Live Variables. + if (MO->isUndef()) { + // An <undef> doesn't refer to any register, so just skip it. + } else if (MO->isUse()) { + regsLiveInButUnused.erase(Reg); + + bool isKill = false; + unsigned defIdx; + if (MI->isRegTiedToDefOperand(MONum, &defIdx)) { + // A two-addr use counts as a kill if use and def are the same. + unsigned DefReg = MI->getOperand(defIdx).getReg(); + if (Reg == DefReg) { + isKill = true; + // ANd in that case an explicit kill flag is not allowed. + if (MO->isKill()) + report("Illegal kill flag on two-address instruction operand", + MO, MONum); + } else if (TargetRegisterInfo::isPhysicalRegister(Reg)) { + report("Two-address instruction operands must be identical", + MO, MONum); + } + } else + isKill = MO->isKill(); + + if (isKill) { + addRegWithSubRegs(regsKilled, Reg); + + // Check that LiveVars knows this kill + if (LiveVars && TargetRegisterInfo::isVirtualRegister(Reg)) { + LiveVariables::VarInfo &VI = LiveVars->getVarInfo(Reg); + if (std::find(VI.Kills.begin(), + VI.Kills.end(), MI) == VI.Kills.end()) + report("Kill missing from LiveVariables", MO, MONum); + } + } + + // Use of a dead register. + if (!regsLive.count(Reg)) { + if (TargetRegisterInfo::isPhysicalRegister(Reg)) { + // Reserved registers may be used even when 'dead'. + if (!isReserved(Reg)) + report("Using an undefined physical register", MO, MONum); + } else { + BBInfo &MInfo = MBBInfoMap[MI->getParent()]; + // We don't know which virtual registers are live in, so only complain + // if vreg was killed in this MBB. Otherwise keep track of vregs that + // must be live in. PHI instructions are handled separately. + if (MInfo.regsKilled.count(Reg)) + report("Using a killed virtual register", MO, MONum); + else if (!MI->isPHI()) + MInfo.vregsLiveIn.insert(std::make_pair(Reg, MI)); + } + } + } else { + assert(MO->isDef()); + // Register defined. + // TODO: verify that earlyclobber ops are not used. + if (MO->isDead()) + addRegWithSubRegs(regsDead, Reg); + else + addRegWithSubRegs(regsDefined, Reg); + } + + // Check register classes. + if (MONum < TI.getNumOperands() && !MO->isImplicit()) { + const TargetOperandInfo &TOI = TI.OpInfo[MONum]; + unsigned SubIdx = MO->getSubReg(); + + if (TargetRegisterInfo::isPhysicalRegister(Reg)) { + unsigned sr = Reg; + if (SubIdx) { + unsigned s = TRI->getSubReg(Reg, SubIdx); + if (!s) { + report("Invalid subregister index for physical register", + MO, MONum); + return; + } + sr = s; + } + if (const TargetRegisterClass *DRC = TOI.getRegClass(TRI)) { + if (!DRC->contains(sr)) { + report("Illegal physical register for instruction", MO, MONum); + *OS << TRI->getName(sr) << " is not a " + << DRC->getName() << " register.\n"; + } + } + } else { + // Virtual register. + const TargetRegisterClass *RC = MRI->getRegClass(Reg); + if (SubIdx) { + const TargetRegisterClass *SRC = RC->getSubRegisterRegClass(SubIdx); + if (!SRC) { + report("Invalid subregister index for virtual register", MO, MONum); + *OS << "Register class " << RC->getName() + << " does not support subreg index " << SubIdx << "\n"; + return; + } + RC = SRC; + } + if (const TargetRegisterClass *DRC = TOI.getRegClass(TRI)) { + if (RC != DRC && !RC->hasSuperClass(DRC)) { + report("Illegal virtual register for instruction", MO, MONum); + *OS << "Expected a " << DRC->getName() << " register, but got a " + << RC->getName() << " register\n"; + } + } + } + } + break; + } + + case MachineOperand::MO_MachineBasicBlock: + if (MI->isPHI() && !MO->getMBB()->isSuccessor(MI->getParent())) + report("PHI operand is not in the CFG", MO, MONum); + break; + + default: + break; + } +} + +void MachineVerifier::visitMachineInstrAfter(const MachineInstr *MI) { + BBInfo &MInfo = MBBInfoMap[MI->getParent()]; + set_union(MInfo.regsKilled, regsKilled); + set_subtract(regsLive, regsKilled); + regsKilled.clear(); + + // Verify that both <def> and <def,dead> operands refer to dead registers. + RegVector defs(regsDefined); + defs.append(regsDead.begin(), regsDead.end()); + + for (RegVector::const_iterator I = defs.begin(), E = defs.end(); + I != E; ++I) { + if (regsLive.count(*I)) { + if (TargetRegisterInfo::isPhysicalRegister(*I)) { + if (!allowPhysDoubleDefs && !isReserved(*I) && + !regsLiveInButUnused.count(*I)) { + report("Redefining a live physical register", MI); + *OS << "Register " << TRI->getName(*I) + << " was defined but already live.\n"; + } + } else { + if (!allowVirtDoubleDefs) { + report("Redefining a live virtual register", MI); + *OS << "Virtual register %reg" << *I + << " was defined but already live.\n"; + } + } + } else if (TargetRegisterInfo::isVirtualRegister(*I) && + !MInfo.regsKilled.count(*I)) { + // Virtual register defined without being killed first must be dead on + // entry. + MInfo.vregsDeadIn.insert(std::make_pair(*I, MI)); + } + } + + set_subtract(regsLive, regsDead); regsDead.clear(); + set_union(regsLive, regsDefined); regsDefined.clear(); +} + +void +MachineVerifier::visitMachineBasicBlockAfter(const MachineBasicBlock *MBB) { + MBBInfoMap[MBB].regsLiveOut = regsLive; + regsLive.clear(); +} + +// Calculate the largest possible vregsPassed sets. These are the registers that +// can pass through an MBB live, but may not be live every time. It is assumed +// that all vregsPassed sets are empty before the call. +void MachineVerifier::calcRegsPassed() { + // First push live-out regs to successors' vregsPassed. Remember the MBBs that + // have any vregsPassed. + DenseSet<const MachineBasicBlock*> todo; + for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); + MFI != MFE; ++MFI) { + const MachineBasicBlock &MBB(*MFI); + BBInfo &MInfo = MBBInfoMap[&MBB]; + if (!MInfo.reachable) + continue; + for (MachineBasicBlock::const_succ_iterator SuI = MBB.succ_begin(), + SuE = MBB.succ_end(); SuI != SuE; ++SuI) { + BBInfo &SInfo = MBBInfoMap[*SuI]; + if (SInfo.addPassed(MInfo.regsLiveOut)) + todo.insert(*SuI); + } + } + + // Iteratively push vregsPassed to successors. This will converge to the same + // final state regardless of DenseSet iteration order. + while (!todo.empty()) { + const MachineBasicBlock *MBB = *todo.begin(); + todo.erase(MBB); + BBInfo &MInfo = MBBInfoMap[MBB]; + for (MachineBasicBlock::const_succ_iterator SuI = MBB->succ_begin(), + SuE = MBB->succ_end(); SuI != SuE; ++SuI) { + if (*SuI == MBB) + continue; + BBInfo &SInfo = MBBInfoMap[*SuI]; + if (SInfo.addPassed(MInfo.vregsPassed)) + todo.insert(*SuI); + } + } +} + +// Calculate the set of virtual registers that must be passed through each basic +// block in order to satisfy the requirements of successor blocks. This is very +// similar to calcRegsPassed, only backwards. +void MachineVerifier::calcRegsRequired() { + // First push live-in regs to predecessors' vregsRequired. + DenseSet<const MachineBasicBlock*> todo; + for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); + MFI != MFE; ++MFI) { + const MachineBasicBlock &MBB(*MFI); + BBInfo &MInfo = MBBInfoMap[&MBB]; + for (MachineBasicBlock::const_pred_iterator PrI = MBB.pred_begin(), + PrE = MBB.pred_end(); PrI != PrE; ++PrI) { + BBInfo &PInfo = MBBInfoMap[*PrI]; + if (PInfo.addRequired(MInfo.vregsLiveIn)) + todo.insert(*PrI); + } + } + + // Iteratively push vregsRequired to predecessors. This will converge to the + // same final state regardless of DenseSet iteration order. + while (!todo.empty()) { + const MachineBasicBlock *MBB = *todo.begin(); + todo.erase(MBB); + BBInfo &MInfo = MBBInfoMap[MBB]; + for (MachineBasicBlock::const_pred_iterator PrI = MBB->pred_begin(), + PrE = MBB->pred_end(); PrI != PrE; ++PrI) { + if (*PrI == MBB) + continue; + BBInfo &SInfo = MBBInfoMap[*PrI]; + if (SInfo.addRequired(MInfo.vregsRequired)) + todo.insert(*PrI); + } + } +} + +// Check PHI instructions at the beginning of MBB. It is assumed that +// calcRegsPassed has been run so BBInfo::isLiveOut is valid. +void MachineVerifier::checkPHIOps(const MachineBasicBlock *MBB) { + for (MachineBasicBlock::const_iterator BBI = MBB->begin(), BBE = MBB->end(); + BBI != BBE && BBI->isPHI(); ++BBI) { + DenseSet<const MachineBasicBlock*> seen; + + for (unsigned i = 1, e = BBI->getNumOperands(); i != e; i += 2) { + unsigned Reg = BBI->getOperand(i).getReg(); + const MachineBasicBlock *Pre = BBI->getOperand(i + 1).getMBB(); + if (!Pre->isSuccessor(MBB)) + continue; + seen.insert(Pre); + BBInfo &PrInfo = MBBInfoMap[Pre]; + if (PrInfo.reachable && !PrInfo.isLiveOut(Reg)) + report("PHI operand is not live-out from predecessor", + &BBI->getOperand(i), i); + } + + // Did we see all predecessors? + for (MachineBasicBlock::const_pred_iterator PrI = MBB->pred_begin(), + PrE = MBB->pred_end(); PrI != PrE; ++PrI) { + if (!seen.count(*PrI)) { + report("Missing PHI operand", BBI); + *OS << "BB#" << (*PrI)->getNumber() + << " is a predecessor according to the CFG.\n"; + } + } + } +} + +void MachineVerifier::visitMachineFunctionAfter() { + calcRegsPassed(); + + for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); + MFI != MFE; ++MFI) { + BBInfo &MInfo = MBBInfoMap[MFI]; + + // Skip unreachable MBBs. + if (!MInfo.reachable) + continue; + + checkPHIOps(MFI); + + // Verify dead-in virtual registers. + if (!allowVirtDoubleDefs) { + for (MachineBasicBlock::const_pred_iterator PrI = MFI->pred_begin(), + PrE = MFI->pred_end(); PrI != PrE; ++PrI) { + BBInfo &PrInfo = MBBInfoMap[*PrI]; + if (!PrInfo.reachable) + continue; + + for (RegMap::iterator I = MInfo.vregsDeadIn.begin(), + E = MInfo.vregsDeadIn.end(); I != E; ++I) { + // DeadIn register must be in neither regsLiveOut or vregsPassed of + // any predecessor. + if (PrInfo.isLiveOut(I->first)) { + report("Live-in virtual register redefined", I->second); + *OS << "Register %reg" << I->first + << " was live-out from predecessor MBB #" + << (*PrI)->getNumber() << ".\n"; + } + } + } + } + } + + // Now check LiveVariables info if available + if (LiveVars) { + calcRegsRequired(); + verifyLiveVariables(); + } +} + +void MachineVerifier::verifyLiveVariables() { + assert(LiveVars && "Don't call verifyLiveVariables without LiveVars"); + for (unsigned Reg = TargetRegisterInfo::FirstVirtualRegister, + RegE = MRI->getLastVirtReg()-1; Reg != RegE; ++Reg) { + LiveVariables::VarInfo &VI = LiveVars->getVarInfo(Reg); + for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); + MFI != MFE; ++MFI) { + BBInfo &MInfo = MBBInfoMap[MFI]; + + // Our vregsRequired should be identical to LiveVariables' AliveBlocks + if (MInfo.vregsRequired.count(Reg)) { + if (!VI.AliveBlocks.test(MFI->getNumber())) { + report("LiveVariables: Block missing from AliveBlocks", MFI); + *OS << "Virtual register %reg" << Reg + << " must be live through the block.\n"; + } + } else { + if (VI.AliveBlocks.test(MFI->getNumber())) { + report("LiveVariables: Block should not be in AliveBlocks", MFI); + *OS << "Virtual register %reg" << Reg + << " is not needed live through the block.\n"; + } + } + } + } +} + + |
