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llvm-project/llvm/lib/CodeGen/MachineVerifier.cpp

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//===-- MachineVerifier.cpp - Machine Code Verifier -----------------------===//
//
// 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/LiveIntervalAnalysis.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) :
PASS(pass),
OutFileName(getenv("LLVM_VERIFY_MACHINEINSTRS"))
{}
bool runOnMachineFunction(MachineFunction &MF);
Pass *const PASS;
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;
// 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;
const LiveIntervals *LiveInts;
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();
void verifyLiveIntervals();
};
struct MachineVerifierPass : public MachineFunctionPass {
static char ID; // Pass ID, replacement for typeid
MachineVerifierPass()
: MachineFunctionPass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool runOnMachineFunction(MachineFunction &MF) {
MF.verify(this);
return false;
}
};
}
char MachineVerifierPass::ID = 0;
INITIALIZE_PASS(MachineVerifierPass, "machineverifier",
"Verify generated machine code", false, false);
FunctionPass *llvm::createMachineVerifierPass() {
return new MachineVerifierPass();
}
void MachineFunction::verify(Pass *p) const {
MachineVerifier(p).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();
LiveVars = NULL;
LiveInts = NULL;
if (PASS) {
LiveInts = PASS->getAnalysisIfAvailable<LiveIntervals>();
// We don't want to verify LiveVariables if LiveIntervals is available.
if (!LiveInts)
LiveVars = PASS->getAnalysisIfAvailable<LiveVariables>();
}
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() &&
!TII->isPredicated(&MBB->back())) {
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);
}
// Debug values must not have a slot index.
// Other instructions must have one.
if (LiveInts) {
bool mapped = !LiveInts->isNotInMIMap(MI);
if (MI->isDebugValue()) {
if (mapped)
report("Debug instruction has a slot index", MI);
} else {
if (!mapped)
report("Missing slot index", 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) &&
MO->isKill()) {
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);
}
// Check LiveInts liveness and kill.
if (LiveInts && !LiveInts->isNotInMIMap(MI)) {
SlotIndex UseIdx = LiveInts->getInstructionIndex(MI).getUseIndex();
if (LiveInts->hasInterval(Reg)) {
const LiveInterval &LI = LiveInts->getInterval(Reg);
if (!LI.liveAt(UseIdx)) {
report("No live range at use", MO, MONum);
*OS << UseIdx << " is not live in " << LI << '\n';
}
// TODO: Verify isKill == LI.killedAt.
} else if (TargetRegisterInfo::isVirtualRegister(Reg)) {
report("Virtual register has no Live interval", 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 LiveInts for a live range, but only for virtual registers.
if (LiveInts && TargetRegisterInfo::isVirtualRegister(Reg) &&
!LiveInts->isNotInMIMap(MI)) {
SlotIndex DefIdx = LiveInts->getInstructionIndex(MI).getDefIndex();
if (LiveInts->hasInterval(Reg)) {
const LiveInterval &LI = LiveInts->getInterval(Reg);
if (const VNInfo *VNI = LI.getVNInfoAt(DefIdx)) {
assert(VNI && "NULL valno is not allowed");
if (VNI->def != DefIdx) {
report("Inconsistent valno->def", MO, MONum);
*OS << "Valno " << VNI->id << " is not defined at "
<< DefIdx << " in " << LI << '\n';
}
} else {
report("No live range at def", MO, MONum);
*OS << DefIdx << " is not live in " << LI << '\n';
}
} else {
report("Virtual register has no Live interval", MO, MONum);
}
}
}
// 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();
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);
}
// Now check liveness info if available
if (LiveVars || LiveInts)
calcRegsRequired();
if (LiveVars)
verifyLiveVariables();
if (LiveInts)
verifyLiveIntervals();
}
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";
}
}
}
}
}
void MachineVerifier::verifyLiveIntervals() {
assert(LiveInts && "Don't call verifyLiveIntervals without LiveInts");
for (LiveIntervals::const_iterator LVI = LiveInts->begin(),
LVE = LiveInts->end(); LVI != LVE; ++LVI) {
const LiveInterval &LI = *LVI->second;
assert(LVI->first == LI.reg && "Invalid reg to interval mapping");
for (LiveInterval::const_vni_iterator I = LI.vni_begin(), E = LI.vni_end();
I!=E; ++I) {
VNInfo *VNI = *I;
const VNInfo *DefVNI = LI.getVNInfoAt(VNI->def);
if (!DefVNI) {
if (!VNI->isUnused()) {
report("Valno not live at def and not marked unused", MF);
*OS << "Valno #" << VNI->id << " in " << LI << '\n';
}
continue;
}
if (VNI->isUnused())
continue;
if (DefVNI != VNI) {
report("Live range at def has different valno", MF);
*OS << "Valno #" << VNI->id << " is defined at " << VNI->def
<< " where valno #" << DefVNI->id << " is live.\n";
}
}
for (LiveInterval::const_iterator I = LI.begin(), E = LI.end(); I!=E; ++I) {
const VNInfo *VNI = I->valno;
assert(VNI && "Live range has no valno");
if (VNI->id >= LI.getNumValNums() || VNI != LI.getValNumInfo(VNI->id)) {
report("Foreign valno in live range", MF);
I->print(*OS);
*OS << " has a valno not in " << LI << '\n';
}
if (VNI->isUnused()) {
report("Live range valno is marked unused", MF);
I->print(*OS);
*OS << " in " << LI << '\n';
}
}
}
}
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