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llvm/lib/CodeGen/MachineVerifier.cpp
Evan Cheng 86050dc8cc Allow ARM if-converter to be run after post allocation scheduling. 
- This fixed a number of bugs in if-converter, tail merging, and post-allocation
  scheduler. If-converter now runs branch folding / tail merging first to
  maximize if-conversion opportunities.
- Also changed the t2IT instruction slightly. It now defines the ITSTATE
  register which is read by instructions in the IT block.
- Added Thumb2 specific hazard recognizer to ensure the scheduler doesn't
  change the instruction ordering in the IT block (since IT mask has been
  finalized). It also ensures no other instructions can be scheduled between
  instructions in the IT block.

This is not yet enabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106344 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-18 23:09:54 +00:00

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31 KiB
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//===-- 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() &&
!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);
}
}
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";
}
}
}
}
}
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