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llvm-6502/lib/CodeGen/MachineVerifier.cpp
Matthias Braun 97c5de758a MachineFrameInfo: Simplify pristine register calculation. 
About pristine regsiters:
Pristine registers "hold a value that is useless to the current
function, but that must be preserved - they are callee saved registers
that have not been saved." This concept saves compile time as it frees
the prologue/epilogue inserter from adding every such register to every
basic blocks live-in list.

However the current code in getPristineRegs is formulated in a
complicated way: Inside the function prologue and epilogue all callee
saves are considered pristine, while in the rest of the code only the
non-saved ones are considered pristine.  This requires logic to
differentiate between prologue/epilogue and the rest and in the presence
of shrink-wrapping this even becomes complicated/expensive.  It's also
unnecessary because the prologue epilogue inserters already mark
callee-save registers that are saved/restores properly in the respective
blocks in the prologue/epilogue (see updateLiveness() in
PrologueEpilogueInserter.cpp). So only declaring non-saved/restored
callee saved registers as pristine just works.

Differential Revision: http://reviews.llvm.org/D10101

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238524 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-28 23:20:35 +00:00

1821 lines
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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/CodeGen/Passes.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/LiveStackAnalysis.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Instructions.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
namespace {
struct MachineVerifier {
MachineVerifier(Pass *pass, const char *b) :
PASS(pass),
Banner(b)
{}
bool runOnMachineFunction(MachineFunction &MF);
Pass *const PASS;
const char *Banner;
const MachineFunction *MF;
const TargetMachine *TM;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
const MachineRegisterInfo *MRI;
unsigned foundErrors;
typedef SmallVector<unsigned, 16> RegVector;
typedef SmallVector<const uint32_t*, 4> RegMaskVector;
typedef DenseSet<unsigned> RegSet;
typedef DenseMap<unsigned, const MachineInstr*> RegMap;
typedef SmallPtrSet<const MachineBasicBlock*, 8> BlockSet;
const MachineInstr *FirstTerminator;
BlockSet FunctionBlocks;
BitVector regsReserved;
RegSet regsLive;
RegVector regsDefined, regsDead, regsKilled;
RegMaskVector regMasks;
RegSet regsLiveInButUnused;
SlotIndex lastIndex;
// Add Reg and any sub-registers to RV
void addRegWithSubRegs(RegVector &RV, unsigned Reg) {
RV.push_back(Reg);
if (TargetRegisterInfo::isPhysicalRegister(Reg))
for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
RV.push_back(*SubRegs);
}
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;
// Set versions of block's predecessor and successor lists.
BlockSet Preds, Succs;
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);
}
bool isAllocatable(unsigned Reg) {
return Reg < TRI->getNumRegs() && MRI->isAllocatable(Reg);
}
// Analysis information if available
LiveVariables *LiveVars;
LiveIntervals *LiveInts;
LiveStacks *LiveStks;
SlotIndexes *Indexes;
void visitMachineFunctionBefore();
void visitMachineBasicBlockBefore(const MachineBasicBlock *MBB);
void visitMachineBundleBefore(const MachineInstr *MI);
void visitMachineInstrBefore(const MachineInstr *MI);
void visitMachineOperand(const MachineOperand *MO, unsigned MONum);
void visitMachineInstrAfter(const MachineInstr *MI);
void visitMachineBundleAfter(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 report(const char *msg, const MachineFunction *MF,
const LiveInterval &LI);
void report(const char *msg, const MachineBasicBlock *MBB,
const LiveInterval &LI);
void report(const char *msg, const MachineFunction *MF,
const LiveRange &LR, unsigned Reg, unsigned LaneMask);
void report(const char *msg, const MachineBasicBlock *MBB,
const LiveRange &LR, unsigned Reg, unsigned LaneMask);
void verifyInlineAsm(const MachineInstr *MI);
void checkLiveness(const MachineOperand *MO, unsigned MONum);
void markReachable(const MachineBasicBlock *MBB);
void calcRegsPassed();
void checkPHIOps(const MachineBasicBlock *MBB);
void calcRegsRequired();
void verifyLiveVariables();
void verifyLiveIntervals();
void verifyLiveInterval(const LiveInterval&);
void verifyLiveRangeValue(const LiveRange&, const VNInfo*, unsigned,
unsigned);
void verifyLiveRangeSegment(const LiveRange&,
const LiveRange::const_iterator I, unsigned,
unsigned);
void verifyLiveRange(const LiveRange&, unsigned, unsigned LaneMask = 0);
void verifyStackFrame();
};
struct MachineVerifierPass : public MachineFunctionPass {
static char ID; // Pass ID, replacement for typeid
const std::string Banner;
MachineVerifierPass(const std::string &banner = nullptr)
: MachineFunctionPass(ID), Banner(banner) {
initializeMachineVerifierPassPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool runOnMachineFunction(MachineFunction &MF) override {
MF.verify(this, Banner.c_str());
return false;
}
};
}
char MachineVerifierPass::ID = 0;
INITIALIZE_PASS(MachineVerifierPass, "machineverifier",
"Verify generated machine code", false, false)
FunctionPass *llvm::createMachineVerifierPass(const std::string &Banner) {
return new MachineVerifierPass(Banner);
}
void MachineFunction::verify(Pass *p, const char *Banner) const {
MachineVerifier(p, Banner)
.runOnMachineFunction(const_cast<MachineFunction&>(*this));
}
bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) {
foundErrors = 0;
this->MF = &MF;
TM = &MF.getTarget();
TII = MF.getSubtarget().getInstrInfo();
TRI = MF.getSubtarget().getRegisterInfo();
MRI = &MF.getRegInfo();
LiveVars = nullptr;
LiveInts = nullptr;
LiveStks = nullptr;
Indexes = nullptr;
if (PASS) {
LiveInts = PASS->getAnalysisIfAvailable<LiveIntervals>();
// We don't want to verify LiveVariables if LiveIntervals is available.
if (!LiveInts)
LiveVars = PASS->getAnalysisIfAvailable<LiveVariables>();
LiveStks = PASS->getAnalysisIfAvailable<LiveStacks>();
Indexes = PASS->getAnalysisIfAvailable<SlotIndexes>();
}
visitMachineFunctionBefore();
for (MachineFunction::const_iterator MFI = MF.begin(), MFE = MF.end();
MFI!=MFE; ++MFI) {
visitMachineBasicBlockBefore(MFI);
// Keep track of the current bundle header.
const MachineInstr *CurBundle = nullptr;
// Do we expect the next instruction to be part of the same bundle?
bool InBundle = false;
for (MachineBasicBlock::const_instr_iterator MBBI = MFI->instr_begin(),
MBBE = MFI->instr_end(); MBBI != MBBE; ++MBBI) {
if (MBBI->getParent() != MFI) {
report("Bad instruction parent pointer", MFI);
errs() << "Instruction: " << *MBBI;
continue;
}
// Check for consistent bundle flags.
if (InBundle && !MBBI->isBundledWithPred())
report("Missing BundledPred flag, "
"BundledSucc was set on predecessor", MBBI);
if (!InBundle && MBBI->isBundledWithPred())
report("BundledPred flag is set, "
"but BundledSucc not set on predecessor", MBBI);
// Is this a bundle header?
if (!MBBI->isInsideBundle()) {
if (CurBundle)
visitMachineBundleAfter(CurBundle);
CurBundle = MBBI;
visitMachineBundleBefore(CurBundle);
} else if (!CurBundle)
report("No bundle header", MBBI);
visitMachineInstrBefore(MBBI);
for (unsigned I = 0, E = MBBI->getNumOperands(); I != E; ++I) {
const MachineInstr &MI = *MBBI;
const MachineOperand &Op = MI.getOperand(I);
if (Op.getParent() != &MI) {
// Make sure to use correct addOperand / RemoveOperand / ChangeTo
// functions when replacing operands of a MachineInstr.
report("Instruction has operand with wrong parent set", &MI);
}
visitMachineOperand(&Op, I);
}
visitMachineInstrAfter(MBBI);
// Was this the last bundled instruction?
InBundle = MBBI->isBundledWithSucc();
}
if (CurBundle)
visitMachineBundleAfter(CurBundle);
if (InBundle)
report("BundledSucc flag set on last instruction in block", &MFI->back());
visitMachineBasicBlockAfter(MFI);
}
visitMachineFunctionAfter();
if (foundErrors)
report_fatal_error("Found "+Twine(foundErrors)+" machine code errors.");
// Clean up.
regsLive.clear();
regsDefined.clear();
regsDead.clear();
regsKilled.clear();
regMasks.clear();
regsLiveInButUnused.clear();
MBBInfoMap.clear();
return false; // no changes
}
void MachineVerifier::report(const char *msg, const MachineFunction *MF) {
assert(MF);
errs() << '\n';
if (!foundErrors++) {
if (Banner)
errs() << "# " << Banner << '\n';
MF->print(errs(), Indexes);
}
errs() << "*** Bad machine code: " << msg << " ***\n"
<< "- function: " << MF->getName() << "\n";
}
void MachineVerifier::report(const char *msg, const MachineBasicBlock *MBB) {
assert(MBB);
report(msg, MBB->getParent());
errs() << "- basic block: BB#" << MBB->getNumber()
<< ' ' << MBB->getName()
<< " (" << (const void*)MBB << ')';
if (Indexes)
errs() << " [" << Indexes->getMBBStartIdx(MBB)
<< ';' << Indexes->getMBBEndIdx(MBB) << ')';
errs() << '\n';
}
void MachineVerifier::report(const char *msg, const MachineInstr *MI) {
assert(MI);
report(msg, MI->getParent());
errs() << "- instruction: ";
if (Indexes && Indexes->hasIndex(MI))
errs() << Indexes->getInstructionIndex(MI) << '\t';
MI->print(errs(), TM);
}
void MachineVerifier::report(const char *msg,
const MachineOperand *MO, unsigned MONum) {
assert(MO);
report(msg, MO->getParent());
errs() << "- operand " << MONum << ": ";
MO->print(errs(), TRI);
errs() << "\n";
}
void MachineVerifier::report(const char *msg, const MachineFunction *MF,
const LiveInterval &LI) {
report(msg, MF);
errs() << "- interval: " << LI << '\n';
}
void MachineVerifier::report(const char *msg, const MachineBasicBlock *MBB,
const LiveInterval &LI) {
report(msg, MBB);
errs() << "- interval: " << LI << '\n';
}
void MachineVerifier::report(const char *msg, const MachineBasicBlock *MBB,
const LiveRange &LR, unsigned Reg,
unsigned LaneMask) {
report(msg, MBB);
errs() << "- liverange: " << LR << '\n';
errs() << "- register: " << PrintReg(Reg, TRI) << '\n';
if (LaneMask != 0)
errs() << "- lanemask: " << format("%04X\n", LaneMask);
}
void MachineVerifier::report(const char *msg, const MachineFunction *MF,
const LiveRange &LR, unsigned Reg,
unsigned LaneMask) {
report(msg, MF);
errs() << "- liverange: " << LR << '\n';
errs() << "- register: " << PrintReg(Reg, TRI) << '\n';
if (LaneMask != 0)
errs() << "- lanemask: " << format("%04X\n", LaneMask);
}
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() {
lastIndex = SlotIndex();
regsReserved = MRI->getReservedRegs();
// A sub-register of a reserved register is also reserved
for (int Reg = regsReserved.find_first(); Reg>=0;
Reg = regsReserved.find_next(Reg)) {
for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
// FIXME: This should probably be:
// assert(regsReserved.test(*SubRegs) && "Non-reserved sub-register");
regsReserved.set(*SubRegs);
}
}
markReachable(&MF->front());
// Build a set of the basic blocks in the function.
FunctionBlocks.clear();
for (const auto &MBB : *MF) {
FunctionBlocks.insert(&MBB);
BBInfo &MInfo = MBBInfoMap[&MBB];
MInfo.Preds.insert(MBB.pred_begin(), MBB.pred_end());
if (MInfo.Preds.size() != MBB.pred_size())
report("MBB has duplicate entries in its predecessor list.", &MBB);
MInfo.Succs.insert(MBB.succ_begin(), MBB.succ_end());
if (MInfo.Succs.size() != MBB.succ_size())
report("MBB has duplicate entries in its successor list.", &MBB);
}
// Check that the register use lists are sane.
MRI->verifyUseLists();
verifyStackFrame();
}
// 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) {
FirstTerminator = nullptr;
if (MRI->isSSA()) {
// If this block has allocatable physical registers live-in, check that
// it is an entry block or landing pad.
for (MachineBasicBlock::livein_iterator LI = MBB->livein_begin(),
LE = MBB->livein_end();
LI != LE; ++LI) {
unsigned reg = *LI;
if (isAllocatable(reg) && !MBB->isLandingPad() &&
MBB != MBB->getParent()->begin()) {
report("MBB has allocable live-in, but isn't entry or landing-pad.", MBB);
}
}
}
// Count the number of landing pad successors.
SmallPtrSet<MachineBasicBlock*, 4> LandingPadSuccs;
for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
E = MBB->succ_end(); I != E; ++I) {
if ((*I)->isLandingPad())
LandingPadSuccs.insert(*I);
if (!FunctionBlocks.count(*I))
report("MBB has successor that isn't part of the function.", MBB);
if (!MBBInfoMap[*I].Preds.count(MBB)) {
report("Inconsistent CFG", MBB);
errs() << "MBB is not in the predecessor list of the successor BB#"
<< (*I)->getNumber() << ".\n";
}
}
// Check the predecessor list.
for (MachineBasicBlock::const_pred_iterator I = MBB->pred_begin(),
E = MBB->pred_end(); I != E; ++I) {
if (!FunctionBlocks.count(*I))
report("MBB has predecessor that isn't part of the function.", MBB);
if (!MBBInfoMap[*I].Succs.count(MBB)) {
report("Inconsistent CFG", MBB);
errs() << "MBB is not in the successor list of the predecessor BB#"
<< (*I)->getNumber() << ".\n";
}
}
const MCAsmInfo *AsmInfo = TM->getMCAsmInfo();
const BasicBlock *BB = MBB->getBasicBlock();
if (LandingPadSuccs.size() > 1 &&
!(AsmInfo &&
AsmInfo->getExceptionHandlingType() == ExceptionHandling::SjLj &&
BB && isa<SwitchInst>(BB->getTerminator())))
report("MBB has more than one landing pad successor", MBB);
// Call AnalyzeBranch. If it succeeds, there several more conditions to check.
MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
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_size() == LandingPadSuccs.size()) {
// 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+LandingPadSuccs.size()) {
report("MBB exits via unconditional fall-through but doesn't have "
"exactly one CFG successor!", MBB);
} else if (!MBB->isSuccessor(MBBI)) {
report("MBB exits via unconditional fall-through but its successor "
"differs from its CFG successor!", MBB);
}
if (!MBB->empty() && MBB->back().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 the block has exactly one successor, that happens to be a
// landingpad, accept it as valid control flow.
if (MBB->succ_size() != 1+LandingPadSuccs.size() &&
(MBB->succ_size() != 1 || LandingPadSuccs.size() != 1 ||
*MBB->succ_begin() != *LandingPadSuccs.begin())) {
report("MBB exits via unconditional branch but doesn't have "
"exactly one CFG successor!", MBB);
} else if (!MBB->isSuccessor(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().isBarrier()) {
report("MBB exits via unconditional branch but doesn't end with a "
"barrier instruction!", MBB);
} else if (!MBB->back().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);
} else if (MBB->succ_size() == 1) {
// A conditional branch with only one successor is weird, but allowed.
if (&*MBBI != TBB)
report("MBB exits via conditional branch/fall-through but only has "
"one CFG successor!", MBB);
else if (TBB != *MBB->succ_begin())
report("MBB exits via conditional branch/fall-through but the CFG "
"successor don't match the actual successor!", MBB);
} else 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().isBarrier()) {
report("MBB exits via conditional branch/fall-through but ends with a "
"barrier instruction!", MBB);
} else if (!MBB->back().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() == 1) {
// A conditional branch with only one successor is weird, but allowed.
if (FBB != TBB)
report("MBB exits via conditional branch/branch through but only has "
"one CFG successor!", MBB);
else if (TBB != *MBB->succ_begin())
report("MBB exits via conditional branch/branch through but the CFG "
"successor don't match the actual successor!", MBB);
} 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().isBarrier()) {
report("MBB exits via conditional branch/branch but doesn't end with a "
"barrier instruction!", MBB);
} else if (!MBB->back().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;
}
for (MCSubRegIterator SubRegs(*I, TRI, /*IncludeSelf=*/true);
SubRegs.isValid(); ++SubRegs)
regsLive.insert(*SubRegs);
}
regsLiveInButUnused = regsLive;
const MachineFrameInfo *MFI = MF->getFrameInfo();
assert(MFI && "Function has no frame info");
BitVector PR = MFI->getPristineRegs(*MF);
for (int I = PR.find_first(); I>0; I = PR.find_next(I)) {
for (MCSubRegIterator SubRegs(I, TRI, /*IncludeSelf=*/true);
SubRegs.isValid(); ++SubRegs)
regsLive.insert(*SubRegs);
}
regsKilled.clear();
regsDefined.clear();
if (Indexes)
lastIndex = Indexes->getMBBStartIdx(MBB);
}
// This function gets called for all bundle headers, including normal
// stand-alone unbundled instructions.
void MachineVerifier::visitMachineBundleBefore(const MachineInstr *MI) {
if (Indexes && Indexes->hasIndex(MI)) {
SlotIndex idx = Indexes->getInstructionIndex(MI);
if (!(idx > lastIndex)) {
report("Instruction index out of order", MI);
errs() << "Last instruction was at " << lastIndex << '\n';
}
lastIndex = idx;
}
// Ensure non-terminators don't follow terminators.
// Ignore predicated terminators formed by if conversion.
// FIXME: If conversion shouldn't need to violate this rule.
if (MI->isTerminator() && !TII->isPredicated(MI)) {
if (!FirstTerminator)
FirstTerminator = MI;
} else if (FirstTerminator) {
report("Non-terminator instruction after the first terminator", MI);
errs() << "First terminator was:\t" << *FirstTerminator;
}
}
// The operands on an INLINEASM instruction must follow a template.
// Verify that the flag operands make sense.
void MachineVerifier::verifyInlineAsm(const MachineInstr *MI) {
// The first two operands on INLINEASM are the asm string and global flags.
if (MI->getNumOperands() < 2) {
report("Too few operands on inline asm", MI);
return;
}
if (!MI->getOperand(0).isSymbol())
report("Asm string must be an external symbol", MI);
if (!MI->getOperand(1).isImm())
report("Asm flags must be an immediate", MI);
// Allowed flags are Extra_HasSideEffects = 1, Extra_IsAlignStack = 2,
// Extra_AsmDialect = 4, Extra_MayLoad = 8, and Extra_MayStore = 16.
if (!isUInt<5>(MI->getOperand(1).getImm()))
report("Unknown asm flags", &MI->getOperand(1), 1);
static_assert(InlineAsm::MIOp_FirstOperand == 2, "Asm format changed");
unsigned OpNo = InlineAsm::MIOp_FirstOperand;
unsigned NumOps;
for (unsigned e = MI->getNumOperands(); OpNo < e; OpNo += NumOps) {
const MachineOperand &MO = MI->getOperand(OpNo);
// There may be implicit ops after the fixed operands.
if (!MO.isImm())
break;
NumOps = 1 + InlineAsm::getNumOperandRegisters(MO.getImm());
}
if (OpNo > MI->getNumOperands())
report("Missing operands in last group", MI);
// An optional MDNode follows the groups.
if (OpNo < MI->getNumOperands() && MI->getOperand(OpNo).isMetadata())
++OpNo;
// All trailing operands must be implicit registers.
for (unsigned e = MI->getNumOperands(); OpNo < e; ++OpNo) {
const MachineOperand &MO = MI->getOperand(OpNo);
if (!MO.isReg() || !MO.isImplicit())
report("Expected implicit register after groups", &MO, OpNo);
}
}
void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) {
const MCInstrDesc &MCID = MI->getDesc();
if (MI->getNumOperands() < MCID.getNumOperands()) {
report("Too few operands", MI);
errs() << MCID.getNumOperands() << " operands expected, but "
<< MI->getNumOperands() << " given.\n";
}
// Check the tied operands.
if (MI->isInlineAsm())
verifyInlineAsm(MI);
// Check the MachineMemOperands for basic consistency.
for (MachineInstr::mmo_iterator I = MI->memoperands_begin(),
E = MI->memoperands_end(); I != E; ++I) {
if ((*I)->isLoad() && !MI->mayLoad())
report("Missing mayLoad flag", MI);
if ((*I)->isStore() && !MI->mayStore())
report("Missing mayStore flag", MI);
}
// Debug values must not have a slot index.
// Other instructions must have one, unless they are inside a bundle.
if (LiveInts) {
bool mapped = !LiveInts->isNotInMIMap(MI);
if (MI->isDebugValue()) {
if (mapped)
report("Debug instruction has a slot index", MI);
} else if (MI->isInsideBundle()) {
if (mapped)
report("Instruction inside bundle has a slot index", MI);
} else {
if (!mapped)
report("Missing slot index", MI);
}
}
StringRef ErrorInfo;
if (!TII->verifyInstruction(MI, ErrorInfo))
report(ErrorInfo.data(), MI);
}
void
MachineVerifier::visitMachineOperand(const MachineOperand *MO, unsigned MONum) {
const MachineInstr *MI = MO->getParent();
const MCInstrDesc &MCID = MI->getDesc();
// The first MCID.NumDefs operands must be explicit register defines
if (MONum < MCID.getNumDefs()) {
const MCOperandInfo &MCOI = MCID.OpInfo[MONum];
if (!MO->isReg())
report("Explicit definition must be a register", MO, MONum);
else if (!MO->isDef() && !MCOI.isOptionalDef())
report("Explicit definition marked as use", MO, MONum);
else if (MO->isImplicit())
report("Explicit definition marked as implicit", MO, MONum);
} else if (MONum < MCID.getNumOperands()) {
const MCOperandInfo &MCOI = MCID.OpInfo[MONum];
// Don't check if it's the last operand in a variadic instruction. See,
// e.g., LDM_RET in the arm back end.
if (MO->isReg() &&
!(MI->isVariadic() && MONum == MCID.getNumOperands()-1)) {
if (MO->isDef() && !MCOI.isOptionalDef())
report("Explicit operand marked as def", MO, MONum);
if (MO->isImplicit())
report("Explicit operand marked as implicit", MO, MONum);
}
int TiedTo = MCID.getOperandConstraint(MONum, MCOI::TIED_TO);
if (TiedTo != -1) {
if (!MO->isReg())
report("Tied use must be a register", MO, MONum);
else if (!MO->isTied())
report("Operand should be tied", MO, MONum);
else if (unsigned(TiedTo) != MI->findTiedOperandIdx(MONum))
report("Tied def doesn't match MCInstrDesc", MO, MONum);
} else if (MO->isReg() && MO->isTied())
report("Explicit operand should not be tied", MO, MONum);
} else {
// ARM adds %reg0 operands to indicate predicates. We'll allow that.
if (MO->isReg() && !MO->isImplicit() && !MI->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;
if (MRI->tracksLiveness() && !MI->isDebugValue())
checkLiveness(MO, MONum);
// Verify the consistency of tied operands.
if (MO->isTied()) {
unsigned OtherIdx = MI->findTiedOperandIdx(MONum);
const MachineOperand &OtherMO = MI->getOperand(OtherIdx);
if (!OtherMO.isReg())
report("Must be tied to a register", MO, MONum);
if (!OtherMO.isTied())
report("Missing tie flags on tied operand", MO, MONum);
if (MI->findTiedOperandIdx(OtherIdx) != MONum)
report("Inconsistent tie links", MO, MONum);
if (MONum < MCID.getNumDefs()) {
if (OtherIdx < MCID.getNumOperands()) {
if (-1 == MCID.getOperandConstraint(OtherIdx, MCOI::TIED_TO))
report("Explicit def tied to explicit use without tie constraint",
MO, MONum);
} else {
if (!OtherMO.isImplicit())
report("Explicit def should be tied to implicit use", MO, MONum);
}
}
}
// Verify two-address constraints after leaving SSA form.
unsigned DefIdx;
if (!MRI->isSSA() && MO->isUse() &&
MI->isRegTiedToDefOperand(MONum, &DefIdx) &&
Reg != MI->getOperand(DefIdx).getReg())
report("Two-address instruction operands must be identical", MO, MONum);
// Check register classes.
if (MONum < MCID.getNumOperands() && !MO->isImplicit()) {
unsigned SubIdx = MO->getSubReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
if (SubIdx) {
report("Illegal subregister index for physical register", MO, MONum);
return;
}
if (const TargetRegisterClass *DRC =
TII->getRegClass(MCID, MONum, TRI, *MF)) {
if (!DRC->contains(Reg)) {
report("Illegal physical register for instruction", MO, MONum);
errs() << TRI->getName(Reg) << " is not a "
<< TRI->getRegClassName(DRC) << " register.\n";
}
}
} else {
// Virtual register.
const TargetRegisterClass *RC = MRI->getRegClass(Reg);
if (SubIdx) {
const TargetRegisterClass *SRC =
TRI->getSubClassWithSubReg(RC, SubIdx);
if (!SRC) {
report("Invalid subregister index for virtual register", MO, MONum);
errs() << "Register class " << TRI->getRegClassName(RC)
<< " does not support subreg index " << SubIdx << "\n";
return;
}
if (RC != SRC) {
report("Invalid register class for subregister index", MO, MONum);
errs() << "Register class " << TRI->getRegClassName(RC)
<< " does not fully support subreg index " << SubIdx << "\n";
return;
}
}
if (const TargetRegisterClass *DRC =
TII->getRegClass(MCID, MONum, TRI, *MF)) {
if (SubIdx) {
const TargetRegisterClass *SuperRC =
TRI->getLargestLegalSuperClass(RC, *MF);
if (!SuperRC) {
report("No largest legal super class exists.", MO, MONum);
return;
}
DRC = TRI->getMatchingSuperRegClass(SuperRC, DRC, SubIdx);
if (!DRC) {
report("No matching super-reg register class.", MO, MONum);
return;
}
}
if (!RC->hasSuperClassEq(DRC)) {
report("Illegal virtual register for instruction", MO, MONum);
errs() << "Expected a " << TRI->getRegClassName(DRC)
<< " register, but got a " << TRI->getRegClassName(RC)
<< " register\n";
}
}
}
}
break;
}
case MachineOperand::MO_RegisterMask:
regMasks.push_back(MO->getRegMask());
break;
case MachineOperand::MO_MachineBasicBlock:
if (MI->isPHI() && !MO->getMBB()->isSuccessor(MI->getParent()))
report("PHI operand is not in the CFG", MO, MONum);
break;
case MachineOperand::MO_FrameIndex:
if (LiveStks && LiveStks->hasInterval(MO->getIndex()) &&
LiveInts && !LiveInts->isNotInMIMap(MI)) {
LiveInterval &LI = LiveStks->getInterval(MO->getIndex());
SlotIndex Idx = LiveInts->getInstructionIndex(MI);
if (MI->mayLoad() && !LI.liveAt(Idx.getRegSlot(true))) {
report("Instruction loads from dead spill slot", MO, MONum);
errs() << "Live stack: " << LI << '\n';
}
if (MI->mayStore() && !LI.liveAt(Idx.getRegSlot())) {
report("Instruction stores to dead spill slot", MO, MONum);
errs() << "Live stack: " << LI << '\n';
}
}
break;
default:
break;
}
}
void MachineVerifier::checkLiveness(const MachineOperand *MO, unsigned MONum) {
const MachineInstr *MI = MO->getParent();
const unsigned Reg = MO->getReg();
// Both use and def operands can read a register.
if (MO->readsReg()) {
regsLiveInButUnused.erase(Reg);
if (MO->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);
// Check the cached regunit intervals.
if (TargetRegisterInfo::isPhysicalRegister(Reg) && !isReserved(Reg)) {
for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) {
if (const LiveRange *LR = LiveInts->getCachedRegUnit(*Units)) {
LiveQueryResult LRQ = LR->Query(UseIdx);
if (!LRQ.valueIn()) {
report("No live segment at use", MO, MONum);
errs() << UseIdx << " is not live in " << PrintRegUnit(*Units, TRI)
<< ' ' << *LR << '\n';
}
if (MO->isKill() && !LRQ.isKill()) {
report("Live range continues after kill flag", MO, MONum);
errs() << PrintRegUnit(*Units, TRI) << ' ' << *LR << '\n';
}
}
}
}
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
if (LiveInts->hasInterval(Reg)) {
// This is a virtual register interval.
const LiveInterval &LI = LiveInts->getInterval(Reg);
LiveQueryResult LRQ = LI.Query(UseIdx);
if (!LRQ.valueIn()) {
report("No live segment at use", MO, MONum);
errs() << UseIdx << " is not live in " << LI << '\n';
}
// Check for extra kill flags.
// Note that we allow missing kill flags for now.
if (MO->isKill() && !LRQ.isKill()) {
report("Live range continues after kill flag", MO, MONum);
errs() << "Live range: " << LI << '\n';
}
} else {
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'.
bool Bad = !isReserved(Reg);
// We are fine if just any subregister has a defined value.
if (Bad) {
for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid();
++SubRegs) {
if (regsLive.count(*SubRegs)) {
Bad = false;
break;
}
}
}
// If there is an additional implicit-use of a super register we stop
// here. By definition we are fine if the super register is not
// (completely) dead, if the complete super register is dead we will
// get a report for its operand.
if (Bad) {
for (const MachineOperand &MOP : MI->uses()) {
if (!MOP.isReg())
continue;
if (!MOP.isImplicit())
continue;
for (MCSubRegIterator SubRegs(MOP.getReg(), TRI); SubRegs.isValid();
++SubRegs) {
if (*SubRegs == Reg) {
Bad = false;
break;
}
}
}
}
if (Bad)
report("Using an undefined physical register", MO, MONum);
} else if (MRI->def_empty(Reg)) {
report("Reading virtual register without a def", 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));
}
}
}
if (MO->isDef()) {
// Register defined.
// TODO: verify that earlyclobber ops are not used.
if (MO->isDead())
addRegWithSubRegs(regsDead, Reg);
else
addRegWithSubRegs(regsDefined, Reg);
// Verify SSA form.
if (MRI->isSSA() && TargetRegisterInfo::isVirtualRegister(Reg) &&
std::next(MRI->def_begin(Reg)) != MRI->def_end())
report("Multiple virtual register defs in SSA form", MO, MONum);
// Check LiveInts for a live segment, but only for virtual registers.
if (LiveInts && TargetRegisterInfo::isVirtualRegister(Reg) &&
!LiveInts->isNotInMIMap(MI)) {
SlotIndex DefIdx = LiveInts->getInstructionIndex(MI);
DefIdx = DefIdx.getRegSlot(MO->isEarlyClobber());
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);
errs() << "Valno " << VNI->id << " is not defined at "
<< DefIdx << " in " << LI << '\n';
}
} else {
report("No live segment at def", MO, MONum);
errs() << DefIdx << " is not live in " << LI << '\n';
}
// Check that, if the dead def flag is present, LiveInts agree.
if (MO->isDead()) {
LiveQueryResult LRQ = LI.Query(DefIdx);
if (!LRQ.isDeadDef()) {
report("Live range continues after dead def flag", MO, MONum);
errs() << "Live range: " << LI << '\n';
}
}
} else {
report("Virtual register has no Live interval", MO, MONum);
}
}
}
}
void MachineVerifier::visitMachineInstrAfter(const MachineInstr *MI) {
}
// This function gets called after visiting all instructions in a bundle. The
// argument points to the bundle header.
// Normal stand-alone instructions are also considered 'bundles', and this
// function is called for all of them.
void MachineVerifier::visitMachineBundleAfter(const MachineInstr *MI) {
BBInfo &MInfo = MBBInfoMap[MI->getParent()];
set_union(MInfo.regsKilled, regsKilled);
set_subtract(regsLive, regsKilled); regsKilled.clear();
// Kill any masked registers.
while (!regMasks.empty()) {
const uint32_t *Mask = regMasks.pop_back_val();
for (RegSet::iterator I = regsLive.begin(), E = regsLive.end(); I != E; ++I)
if (TargetRegisterInfo::isPhysicalRegister(*I) &&
MachineOperand::clobbersPhysReg(Mask, *I))
regsDead.push_back(*I);
}
set_subtract(regsLive, regsDead); regsDead.clear();
set_union(regsLive, regsDefined); regsDefined.clear();
}
void
MachineVerifier::visitMachineBasicBlockAfter(const MachineBasicBlock *MBB) {
MBBInfoMap[MBB].regsLiveOut = regsLive;
regsLive.clear();
if (Indexes) {
SlotIndex stop = Indexes->getMBBEndIdx(MBB);
if (!(stop > lastIndex)) {
report("Block ends before last instruction index", MBB);
errs() << "Block ends at " << stop
<< " last instruction was at " << lastIndex << '\n';
}
lastIndex = stop;
}
}
// 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.
SmallPtrSet<const MachineBasicBlock*, 8> todo;
for (const auto &MBB : *MF) {
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.
SmallPtrSet<const MachineBasicBlock*, 8> todo;
for (const auto &MBB : *MF) {
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) {
SmallPtrSet<const MachineBasicBlock*, 8> seen;
for (const auto &BBI : *MBB) {
if (!BBI.isPHI())
break;
seen.clear();
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);
errs() << "BB#" << (*PrI)->getNumber()
<< " is a predecessor according to the CFG.\n";
}
}
}
}
void MachineVerifier::visitMachineFunctionAfter() {
calcRegsPassed();
for (const auto &MBB : *MF) {
BBInfo &MInfo = MBBInfoMap[&MBB];
// Skip unreachable MBBs.
if (!MInfo.reachable)
continue;
checkPHIOps(&MBB);
}
// Now check liveness info if available
calcRegsRequired();
// Check for killed virtual registers that should be live out.
for (const auto &MBB : *MF) {
BBInfo &MInfo = MBBInfoMap[&MBB];
for (RegSet::iterator
I = MInfo.vregsRequired.begin(), E = MInfo.vregsRequired.end(); I != E;
++I)
if (MInfo.regsKilled.count(*I)) {
report("Virtual register killed in block, but needed live out.", &MBB);
errs() << "Virtual register " << PrintReg(*I)
<< " is used after the block.\n";
}
}
if (!MF->empty()) {
BBInfo &MInfo = MBBInfoMap[&MF->front()];
for (RegSet::iterator
I = MInfo.vregsRequired.begin(), E = MInfo.vregsRequired.end(); I != E;
++I)
report("Virtual register def doesn't dominate all uses.",
MRI->getVRegDef(*I));
}
if (LiveVars)
verifyLiveVariables();
if (LiveInts)
verifyLiveIntervals();
}
void MachineVerifier::verifyLiveVariables() {
assert(LiveVars && "Don't call verifyLiveVariables without LiveVars");
for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
LiveVariables::VarInfo &VI = LiveVars->getVarInfo(Reg);
for (const auto &MBB : *MF) {
BBInfo &MInfo = MBBInfoMap[&MBB];
// Our vregsRequired should be identical to LiveVariables' AliveBlocks
if (MInfo.vregsRequired.count(Reg)) {
if (!VI.AliveBlocks.test(MBB.getNumber())) {
report("LiveVariables: Block missing from AliveBlocks", &MBB);
errs() << "Virtual register " << PrintReg(Reg)
<< " must be live through the block.\n";
}
} else {
if (VI.AliveBlocks.test(MBB.getNumber())) {
report("LiveVariables: Block should not be in AliveBlocks", &MBB);
errs() << "Virtual register " << PrintReg(Reg)
<< " is not needed live through the block.\n";
}
}
}
}
}
void MachineVerifier::verifyLiveIntervals() {
assert(LiveInts && "Don't call verifyLiveIntervals without LiveInts");
for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
// Spilling and splitting may leave unused registers around. Skip them.
if (MRI->reg_nodbg_empty(Reg))
continue;
if (!LiveInts->hasInterval(Reg)) {
report("Missing live interval for virtual register", MF);
errs() << PrintReg(Reg, TRI) << " still has defs or uses\n";
continue;
}
const LiveInterval &LI = LiveInts->getInterval(Reg);
assert(Reg == LI.reg && "Invalid reg to interval mapping");
verifyLiveInterval(LI);
}
// Verify all the cached regunit intervals.
for (unsigned i = 0, e = TRI->getNumRegUnits(); i != e; ++i)
if (const LiveRange *LR = LiveInts->getCachedRegUnit(i))
verifyLiveRange(*LR, i);
}
void MachineVerifier::verifyLiveRangeValue(const LiveRange &LR,
const VNInfo *VNI, unsigned Reg,
unsigned LaneMask) {
if (VNI->isUnused())
return;
const VNInfo *DefVNI = LR.getVNInfoAt(VNI->def);
if (!DefVNI) {
report("Valno not live at def and not marked unused", MF, LR, Reg,
LaneMask);
errs() << "Valno #" << VNI->id << '\n';
return;
}
if (DefVNI != VNI) {
report("Live segment at def has different valno", MF, LR, Reg, LaneMask);
errs() << "Valno #" << VNI->id << " is defined at " << VNI->def
<< " where valno #" << DefVNI->id << " is live\n";
return;
}
const MachineBasicBlock *MBB = LiveInts->getMBBFromIndex(VNI->def);
if (!MBB) {
report("Invalid definition index", MF, LR, Reg, LaneMask);
errs() << "Valno #" << VNI->id << " is defined at " << VNI->def
<< " in " << LR << '\n';
return;
}
if (VNI->isPHIDef()) {
if (VNI->def != LiveInts->getMBBStartIdx(MBB)) {
report("PHIDef value is not defined at MBB start", MBB, LR, Reg,
LaneMask);
errs() << "Valno #" << VNI->id << " is defined at " << VNI->def
<< ", not at the beginning of BB#" << MBB->getNumber() << '\n';
}
return;
}
// Non-PHI def.
const MachineInstr *MI = LiveInts->getInstructionFromIndex(VNI->def);
if (!MI) {
report("No instruction at def index", MBB, LR, Reg, LaneMask);
errs() << "Valno #" << VNI->id << " is defined at " << VNI->def << '\n';
return;
}
if (Reg != 0) {
bool hasDef = false;
bool isEarlyClobber = false;
for (ConstMIBundleOperands MOI(MI); MOI.isValid(); ++MOI) {
if (!MOI->isReg() || !MOI->isDef())
continue;
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
if (MOI->getReg() != Reg)
continue;
} else {
if (!TargetRegisterInfo::isPhysicalRegister(MOI->getReg()) ||
!TRI->hasRegUnit(MOI->getReg(), Reg))
continue;
}
if (LaneMask != 0 &&
(TRI->getSubRegIndexLaneMask(MOI->getSubReg()) & LaneMask) == 0)
continue;
hasDef = true;
if (MOI->isEarlyClobber())
isEarlyClobber = true;
}
if (!hasDef) {
report("Defining instruction does not modify register", MI);
errs() << "Valno #" << VNI->id << " in " << LR << '\n';
}
// Early clobber defs begin at USE slots, but other defs must begin at
// DEF slots.
if (isEarlyClobber) {
if (!VNI->def.isEarlyClobber()) {
report("Early clobber def must be at an early-clobber slot", MBB, LR,
Reg, LaneMask);
errs() << "Valno #" << VNI->id << " is defined at " << VNI->def << '\n';
}
} else if (!VNI->def.isRegister()) {
report("Non-PHI, non-early clobber def must be at a register slot",
MBB, LR, Reg, LaneMask);
errs() << "Valno #" << VNI->id << " is defined at " << VNI->def << '\n';
}
}
}
void MachineVerifier::verifyLiveRangeSegment(const LiveRange &LR,
const LiveRange::const_iterator I,
unsigned Reg, unsigned LaneMask) {
const LiveRange::Segment &S = *I;
const VNInfo *VNI = S.valno;
assert(VNI && "Live segment has no valno");
if (VNI->id >= LR.getNumValNums() || VNI != LR.getValNumInfo(VNI->id)) {
report("Foreign valno in live segment", MF, LR, Reg, LaneMask);
errs() << S << " has a bad valno\n";
}
if (VNI->isUnused()) {
report("Live segment valno is marked unused", MF, LR, Reg, LaneMask);
errs() << S << '\n';
}
const MachineBasicBlock *MBB = LiveInts->getMBBFromIndex(S.start);
if (!MBB) {
report("Bad start of live segment, no basic block", MF, LR, Reg, LaneMask);
errs() << S << '\n';
return;
}
SlotIndex MBBStartIdx = LiveInts->getMBBStartIdx(MBB);
if (S.start != MBBStartIdx && S.start != VNI->def) {
report("Live segment must begin at MBB entry or valno def", MBB, LR, Reg,
LaneMask);
errs() << S << '\n';
}
const MachineBasicBlock *EndMBB =
LiveInts->getMBBFromIndex(S.end.getPrevSlot());
if (!EndMBB) {
report("Bad end of live segment, no basic block", MF, LR, Reg, LaneMask);
errs() << S << '\n';
return;
}
// No more checks for live-out segments.
if (S.end == LiveInts->getMBBEndIdx(EndMBB))
return;
// RegUnit intervals are allowed dead phis.
if (!TargetRegisterInfo::isVirtualRegister(Reg) && VNI->isPHIDef() &&
S.start == VNI->def && S.end == VNI->def.getDeadSlot())
return;
// The live segment is ending inside EndMBB
const MachineInstr *MI =
LiveInts->getInstructionFromIndex(S.end.getPrevSlot());
if (!MI) {
report("Live segment doesn't end at a valid instruction", EndMBB, LR, Reg,
LaneMask);
errs() << S << '\n';
return;
}
// The block slot must refer to a basic block boundary.
if (S.end.isBlock()) {
report("Live segment ends at B slot of an instruction", EndMBB, LR, Reg,
LaneMask);
errs() << S << '\n';
}
if (S.end.isDead()) {
// Segment ends on the dead slot.
// That means there must be a dead def.
if (!SlotIndex::isSameInstr(S.start, S.end)) {
report("Live segment ending at dead slot spans instructions", EndMBB, LR,
Reg, LaneMask);
errs() << S << '\n';
}
}
// A live segment can only end at an early-clobber slot if it is being
// redefined by an early-clobber def.
if (S.end.isEarlyClobber()) {
if (I+1 == LR.end() || (I+1)->start != S.end) {
report("Live segment ending at early clobber slot must be "
"redefined by an EC def in the same instruction", EndMBB, LR, Reg,
LaneMask);
errs() << S << '\n';
}
}
// The following checks only apply to virtual registers. Physreg liveness
// is too weird to check.
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
// A live segment can end with either a redefinition, a kill flag on a
// use, or a dead flag on a def.
bool hasRead = false;
bool hasSubRegDef = false;
for (ConstMIBundleOperands MOI(MI); MOI.isValid(); ++MOI) {
if (!MOI->isReg() || MOI->getReg() != Reg)
continue;
if (LaneMask != 0 &&
(LaneMask & TRI->getSubRegIndexLaneMask(MOI->getSubReg())) == 0)
continue;
if (MOI->isDef() && MOI->getSubReg() != 0)
hasSubRegDef = true;
if (MOI->readsReg())
hasRead = true;
}
if (!S.end.isDead()) {
if (!hasRead) {
// When tracking subregister liveness, the main range must start new
// values on partial register writes, even if there is no read.
if (!MRI->shouldTrackSubRegLiveness(Reg) || LaneMask != 0 ||
!hasSubRegDef) {
report("Instruction ending live segment doesn't read the register",
MI);
errs() << S << " in " << LR << '\n';
}
}
}
}
// Now check all the basic blocks in this live segment.
MachineFunction::const_iterator MFI = MBB;
// Is this live segment the beginning of a non-PHIDef VN?
if (S.start == VNI->def && !VNI->isPHIDef()) {
// Not live-in to any blocks.
if (MBB == EndMBB)
return;
// Skip this block.
++MFI;
}
for (;;) {
assert(LiveInts->isLiveInToMBB(LR, MFI));
// We don't know how to track physregs into a landing pad.
if (!TargetRegisterInfo::isVirtualRegister(Reg) &&
MFI->isLandingPad()) {
if (&*MFI == EndMBB)
break;
++MFI;
continue;
}
// Is VNI a PHI-def in the current block?
bool IsPHI = VNI->isPHIDef() &&
VNI->def == LiveInts->getMBBStartIdx(MFI);
// Check that VNI is live-out of all predecessors.
for (MachineBasicBlock::const_pred_iterator PI = MFI->pred_begin(),
PE = MFI->pred_end(); PI != PE; ++PI) {
SlotIndex PEnd = LiveInts->getMBBEndIdx(*PI);
const VNInfo *PVNI = LR.getVNInfoBefore(PEnd);
// All predecessors must have a live-out value.
if (!PVNI) {
report("Register not marked live out of predecessor", *PI, LR, Reg,
LaneMask);
errs() << "Valno #" << VNI->id << " live into BB#" << MFI->getNumber()
<< '@' << LiveInts->getMBBStartIdx(MFI) << ", not live before "
<< PEnd << '\n';
continue;
}
// Only PHI-defs can take different predecessor values.
if (!IsPHI && PVNI != VNI) {
report("Different value live out of predecessor", *PI, LR, Reg,
LaneMask);
errs() << "Valno #" << PVNI->id << " live out of BB#"
<< (*PI)->getNumber() << '@' << PEnd
<< "\nValno #" << VNI->id << " live into BB#" << MFI->getNumber()
<< '@' << LiveInts->getMBBStartIdx(MFI) << '\n';
}
}
if (&*MFI == EndMBB)
break;
++MFI;
}
}
void MachineVerifier::verifyLiveRange(const LiveRange &LR, unsigned Reg,
unsigned LaneMask) {
for (const VNInfo *VNI : LR.valnos)
verifyLiveRangeValue(LR, VNI, Reg, LaneMask);
for (LiveRange::const_iterator I = LR.begin(), E = LR.end(); I != E; ++I)
verifyLiveRangeSegment(LR, I, Reg, LaneMask);
}
void MachineVerifier::verifyLiveInterval(const LiveInterval &LI) {
unsigned Reg = LI.reg;
assert(TargetRegisterInfo::isVirtualRegister(Reg));
verifyLiveRange(LI, Reg);
unsigned Mask = 0;
unsigned MaxMask = MRI->getMaxLaneMaskForVReg(Reg);
for (const LiveInterval::SubRange &SR : LI.subranges()) {
if ((Mask & SR.LaneMask) != 0)
report("Lane masks of sub ranges overlap in live interval", MF, LI);
if ((SR.LaneMask & ~MaxMask) != 0)
report("Subrange lanemask is invalid", MF, LI);
Mask |= SR.LaneMask;
verifyLiveRange(SR, LI.reg, SR.LaneMask);
if (!LI.covers(SR))
report("A Subrange is not covered by the main range", MF, LI);
}
// Check the LI only has one connected component.
ConnectedVNInfoEqClasses ConEQ(*LiveInts);
unsigned NumComp = ConEQ.Classify(&LI);
if (NumComp > 1) {
report("Multiple connected components in live interval", MF, LI);
for (unsigned comp = 0; comp != NumComp; ++comp) {
errs() << comp << ": valnos";
for (LiveInterval::const_vni_iterator I = LI.vni_begin(),
E = LI.vni_end(); I!=E; ++I)
if (comp == ConEQ.getEqClass(*I))
errs() << ' ' << (*I)->id;
errs() << '\n';
}
}
}
namespace {
// FrameSetup and FrameDestroy can have zero adjustment, so using a single
// integer, we can't tell whether it is a FrameSetup or FrameDestroy if the
// value is zero.
// We use a bool plus an integer to capture the stack state.
struct StackStateOfBB {
StackStateOfBB() : EntryValue(0), ExitValue(0), EntryIsSetup(false),
ExitIsSetup(false) { }
StackStateOfBB(int EntryVal, int ExitVal, bool EntrySetup, bool ExitSetup) :
EntryValue(EntryVal), ExitValue(ExitVal), EntryIsSetup(EntrySetup),
ExitIsSetup(ExitSetup) { }
// Can be negative, which means we are setting up a frame.
int EntryValue;
int ExitValue;
bool EntryIsSetup;
bool ExitIsSetup;
};
}
/// Make sure on every path through the CFG, a FrameSetup <n> is always followed
/// by a FrameDestroy <n>, stack adjustments are identical on all
/// CFG edges to a merge point, and frame is destroyed at end of a return block.
void MachineVerifier::verifyStackFrame() {
unsigned FrameSetupOpcode = TII->getCallFrameSetupOpcode();
unsigned FrameDestroyOpcode = TII->getCallFrameDestroyOpcode();
SmallVector<StackStateOfBB, 8> SPState;
SPState.resize(MF->getNumBlockIDs());
SmallPtrSet<const MachineBasicBlock*, 8> Reachable;
// Visit the MBBs in DFS order.
for (df_ext_iterator<const MachineFunction*,
SmallPtrSet<const MachineBasicBlock*, 8> >
DFI = df_ext_begin(MF, Reachable), DFE = df_ext_end(MF, Reachable);
DFI != DFE; ++DFI) {
const MachineBasicBlock *MBB = *DFI;
StackStateOfBB BBState;
// Check the exit state of the DFS stack predecessor.
if (DFI.getPathLength() >= 2) {
const MachineBasicBlock *StackPred = DFI.getPath(DFI.getPathLength() - 2);
assert(Reachable.count(StackPred) &&
"DFS stack predecessor is already visited.\n");
BBState.EntryValue = SPState[StackPred->getNumber()].ExitValue;
BBState.EntryIsSetup = SPState[StackPred->getNumber()].ExitIsSetup;
BBState.ExitValue = BBState.EntryValue;
BBState.ExitIsSetup = BBState.EntryIsSetup;
}
// Update stack state by checking contents of MBB.
for (const auto &I : *MBB) {
if (I.getOpcode() == FrameSetupOpcode) {
// The first operand of a FrameOpcode should be i32.
int Size = I.getOperand(0).getImm();
assert(Size >= 0 &&
"Value should be non-negative in FrameSetup and FrameDestroy.\n");
if (BBState.ExitIsSetup)
report("FrameSetup is after another FrameSetup", &I);
BBState.ExitValue -= Size;
BBState.ExitIsSetup = true;
}
if (I.getOpcode() == FrameDestroyOpcode) {
// The first operand of a FrameOpcode should be i32.
int Size = I.getOperand(0).getImm();
assert(Size >= 0 &&
"Value should be non-negative in FrameSetup and FrameDestroy.\n");
if (!BBState.ExitIsSetup)
report("FrameDestroy is not after a FrameSetup", &I);
int AbsSPAdj = BBState.ExitValue < 0 ? -BBState.ExitValue :
BBState.ExitValue;
if (BBState.ExitIsSetup && AbsSPAdj != Size) {
report("FrameDestroy <n> is after FrameSetup <m>", &I);
errs() << "FrameDestroy <" << Size << "> is after FrameSetup <"
<< AbsSPAdj << ">.\n";
}
BBState.ExitValue += Size;
BBState.ExitIsSetup = false;
}
}
SPState[MBB->getNumber()] = BBState;
// Make sure the exit state of any predecessor is consistent with the entry
// state.
for (MachineBasicBlock::const_pred_iterator I = MBB->pred_begin(),
E = MBB->pred_end(); I != E; ++I) {
if (Reachable.count(*I) &&
(SPState[(*I)->getNumber()].ExitValue != BBState.EntryValue ||
SPState[(*I)->getNumber()].ExitIsSetup != BBState.EntryIsSetup)) {
report("The exit stack state of a predecessor is inconsistent.", MBB);
errs() << "Predecessor BB#" << (*I)->getNumber() << " has exit state ("
<< SPState[(*I)->getNumber()].ExitValue << ", "
<< SPState[(*I)->getNumber()].ExitIsSetup
<< "), while BB#" << MBB->getNumber() << " has entry state ("
<< BBState.EntryValue << ", " << BBState.EntryIsSetup << ").\n";
}
}
// Make sure the entry state of any successor is consistent with the exit
// state.
for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
E = MBB->succ_end(); I != E; ++I) {
if (Reachable.count(*I) &&
(SPState[(*I)->getNumber()].EntryValue != BBState.ExitValue ||
SPState[(*I)->getNumber()].EntryIsSetup != BBState.ExitIsSetup)) {
report("The entry stack state of a successor is inconsistent.", MBB);
errs() << "Successor BB#" << (*I)->getNumber() << " has entry state ("
<< SPState[(*I)->getNumber()].EntryValue << ", "
<< SPState[(*I)->getNumber()].EntryIsSetup
<< "), while BB#" << MBB->getNumber() << " has exit state ("
<< BBState.ExitValue << ", " << BBState.ExitIsSetup << ").\n";
}
}
// Make sure a basic block with return ends with zero stack adjustment.
if (!MBB->empty() && MBB->back().isReturn()) {
if (BBState.ExitIsSetup)
report("A return block ends with a FrameSetup.", MBB);
if (BBState.ExitValue)
report("A return block ends with a nonzero stack adjustment.", MBB);
}
}
}
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