bool AlignmentFromAssumptions::processAssumption(CallInst *ACall) {
Value *AAPtr;
const SCEV *AlignSCEV, *OffSCEV;
if (!extractAlignmentInfo(ACall, AAPtr, AlignSCEV, OffSCEV))
return false;
const SCEV *AASCEV = SE->getSCEV(AAPtr);
// Apply the assumption to all other users of the specified pointer.
SmallPtrSet<Instruction *, 32> Visited;
SmallVector<Instruction*, 16> WorkList;
for (User *J : AAPtr->users()) {
if (J == ACall)
continue;
if (Instruction *K = dyn_cast<Instruction>(J))
if (isValidAssumeForContext(ACall, K, DT))
WorkList.push_back(K);
}
while (!WorkList.empty()) {
Instruction *J = WorkList.pop_back_val();
if (LoadInst *LI = dyn_cast<LoadInst>(J)) {
unsigned NewAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
LI->getPointerOperand(), SE);
if (NewAlignment > LI->getAlignment()) {
LI->setAlignment(NewAlignment);
++NumLoadAlignChanged;
}
} else if (StoreInst *SI = dyn_cast<StoreInst>(J)) {
unsigned NewAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
SI->getPointerOperand(), SE);
if (NewAlignment > SI->getAlignment()) {
SI->setAlignment(NewAlignment);
++NumStoreAlignChanged;
}
} else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(J)) {
unsigned NewDestAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
MI->getDest(), SE);
// For memory transfers, we need a common alignment for both the
// source and destination. If we have a new alignment for this
// instruction, but only for one operand, save it. If we reach the
// other operand through another assumption later, then we may
// change the alignment at that point.
if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
unsigned NewSrcAlignment = getNewAlignment(AASCEV, AlignSCEV, OffSCEV,
MTI->getSource(), SE);
DenseMap<MemTransferInst *, unsigned>::iterator DI =
NewDestAlignments.find(MTI);
unsigned AltDestAlignment = (DI == NewDestAlignments.end()) ?
0 : DI->second;
DenseMap<MemTransferInst *, unsigned>::iterator SI =
NewSrcAlignments.find(MTI);
unsigned AltSrcAlignment = (SI == NewSrcAlignments.end()) ?
0 : SI->second;
DEBUG(dbgs() << "\tmem trans: " << NewDestAlignment << " " <<
AltDestAlignment << " " << NewSrcAlignment <<
" " << AltSrcAlignment << "\n");
// Of these four alignments, pick the largest possible...
unsigned NewAlignment = 0;
if (NewDestAlignment <= std::max(NewSrcAlignment, AltSrcAlignment))
NewAlignment = std::max(NewAlignment, NewDestAlignment);
if (AltDestAlignment <= std::max(NewSrcAlignment, AltSrcAlignment))
NewAlignment = std::max(NewAlignment, AltDestAlignment);
if (NewSrcAlignment <= std::max(NewDestAlignment, AltDestAlignment))
NewAlignment = std::max(NewAlignment, NewSrcAlignment);
if (AltSrcAlignment <= std::max(NewDestAlignment, AltDestAlignment))
NewAlignment = std::max(NewAlignment, AltSrcAlignment);
if (NewAlignment > MI->getAlignment()) {
MI->setAlignment(ConstantInt::get(Type::getInt32Ty(
MI->getParent()->getContext()), NewAlignment));
++NumMemIntAlignChanged;
}
NewDestAlignments.insert(std::make_pair(MTI, NewDestAlignment));
NewSrcAlignments.insert(std::make_pair(MTI, NewSrcAlignment));
} else if (NewDestAlignment > MI->getAlignment()) {
assert((!isa<MemIntrinsic>(MI) || isa<MemSetInst>(MI)) &&
"Unknown memory intrinsic");
MI->setAlignment(ConstantInt::get(Type::getInt32Ty(
MI->getParent()->getContext()), NewDestAlignment));
++NumMemIntAlignChanged;
}
}
// Now that we've updated that use of the pointer, look for other uses of
// the pointer to update.
Visited.insert(J);
for (User *UJ : J->users()) {
Instruction *K = cast<Instruction>(UJ);
if (!Visited.count(K) && isValidAssumeForContext(ACall, K, DT))
WorkList.push_back(K);
}
}
return true;
}
MachineBasicBlock *
MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
// Splitting the critical edge to a landing pad block is non-trivial. Don't do
// it in this generic function.
if (Succ->isLandingPad())
return NULL;
MachineFunction *MF = getParent();
DebugLoc dl; // FIXME: this is nowhere
// We may need to update this's terminator, but we can't do that if
// AnalyzeBranch fails. If this uses a jump table, we won't touch it.
const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
MachineBasicBlock *TBB = 0, *FBB = 0;
SmallVector<MachineOperand, 4> Cond;
if (TII->AnalyzeBranch(*this, TBB, FBB, Cond))
return NULL;
// Avoid bugpoint weirdness: A block may end with a conditional branch but
// jumps to the same MBB is either case. We have duplicate CFG edges in that
// case that we can't handle. Since this never happens in properly optimized
// code, just skip those edges.
if (TBB && TBB == FBB) {
DEBUG(dbgs() << "Won't split critical edge after degenerate BB#"
<< getNumber() << '\n');
return NULL;
}
MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB);
DEBUG(dbgs() << "Splitting critical edge:"
" BB#" << getNumber()
<< " -- BB#" << NMBB->getNumber()
<< " -- BB#" << Succ->getNumber() << '\n');
// On some targets like Mips, branches may kill virtual registers. Make sure
// that LiveVariables is properly updated after updateTerminator replaces the
// terminators.
LiveVariables *LV = P->getAnalysisIfAvailable<LiveVariables>();
// Collect a list of virtual registers killed by the terminators.
SmallVector<unsigned, 4> KilledRegs;
if (LV)
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I) {
MachineInstr *MI = I;
for (MachineInstr::mop_iterator OI = MI->operands_begin(),
OE = MI->operands_end(); OI != OE; ++OI) {
if (!OI->isReg() || OI->getReg() == 0 ||
!OI->isUse() || !OI->isKill() || OI->isUndef())
continue;
unsigned Reg = OI->getReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
LV->getVarInfo(Reg).removeKill(MI)) {
KilledRegs.push_back(Reg);
DEBUG(dbgs() << "Removing terminator kill: " << *MI);
OI->setIsKill(false);
}
}
}
ReplaceUsesOfBlockWith(Succ, NMBB);
updateTerminator();
// Insert unconditional "jump Succ" instruction in NMBB if necessary.
NMBB->addSuccessor(Succ);
if (!NMBB->isLayoutSuccessor(Succ)) {
Cond.clear();
MF->getTarget().getInstrInfo()->InsertBranch(*NMBB, Succ, NULL, Cond, dl);
}
// Fix PHI nodes in Succ so they refer to NMBB instead of this
for (MachineBasicBlock::instr_iterator
i = Succ->instr_begin(),e = Succ->instr_end();
i != e && i->isPHI(); ++i)
for (unsigned ni = 1, ne = i->getNumOperands(); ni != ne; ni += 2)
if (i->getOperand(ni+1).getMBB() == this)
i->getOperand(ni+1).setMBB(NMBB);
// Inherit live-ins from the successor
for (MachineBasicBlock::livein_iterator I = Succ->livein_begin(),
E = Succ->livein_end(); I != E; ++I)
NMBB->addLiveIn(*I);
// Update LiveVariables.
const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
if (LV) {
// Restore kills of virtual registers that were killed by the terminators.
while (!KilledRegs.empty()) {
unsigned Reg = KilledRegs.pop_back_val();
for (instr_iterator I = instr_end(), E = instr_begin(); I != E;) {
if (!(--I)->addRegisterKilled(Reg, TRI, /* addIfNotFound= */ false))
continue;
if (TargetRegisterInfo::isVirtualRegister(Reg))
LV->getVarInfo(Reg).Kills.push_back(I);
DEBUG(dbgs() << "Restored terminator kill: " << *I);
break;
}
}
// Update relevant live-through information.
LV->addNewBlock(NMBB, this, Succ);
}
if (MachineDominatorTree *MDT =
P->getAnalysisIfAvailable<MachineDominatorTree>()) {
// Update dominator information.
MachineDomTreeNode *SucccDTNode = MDT->getNode(Succ);
bool IsNewIDom = true;
for (const_pred_iterator PI = Succ->pred_begin(), E = Succ->pred_end();
PI != E; ++PI) {
MachineBasicBlock *PredBB = *PI;
if (PredBB == NMBB)
continue;
if (!MDT->dominates(SucccDTNode, MDT->getNode(PredBB))) {
IsNewIDom = false;
break;
}
}
// We know "this" dominates the newly created basic block.
MachineDomTreeNode *NewDTNode = MDT->addNewBlock(NMBB, this);
// If all the other predecessors of "Succ" are dominated by "Succ" itself
// then the new block is the new immediate dominator of "Succ". Otherwise,
// the new block doesn't dominate anything.
if (IsNewIDom)
MDT->changeImmediateDominator(SucccDTNode, NewDTNode);
}
if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
if (MachineLoop *TIL = MLI->getLoopFor(this)) {
// If one or the other blocks were not in a loop, the new block is not
// either, and thus LI doesn't need to be updated.
if (MachineLoop *DestLoop = MLI->getLoopFor(Succ)) {
if (TIL == DestLoop) {
// Both in the same loop, the NMBB joins loop.
DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
} else if (TIL->contains(DestLoop)) {
// Edge from an outer loop to an inner loop. Add to the outer loop.
TIL->addBasicBlockToLoop(NMBB, MLI->getBase());
} else if (DestLoop->contains(TIL)) {
// Edge from an inner loop to an outer loop. Add to the outer loop.
DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
} else {
// Edge from two loops with no containment relation. Because these
// are natural loops, we know that the destination block must be the
// header of its loop (adding a branch into a loop elsewhere would
// create an irreducible loop).
assert(DestLoop->getHeader() == Succ &&
"Should not create irreducible loops!");
if (MachineLoop *P = DestLoop->getParentLoop())
P->addBasicBlockToLoop(NMBB, MLI->getBase());
}
}
}
return NMBB;
}
/// Try to determine the exact dynamic type of an object.
/// returns the exact dynamic type of the object, or an empty type if the exact
/// type could not be determined.
SILType swift::getExactDynamicType(SILValue S, SILModule &M,
ClassHierarchyAnalysis *CHA,
bool ForUnderlyingObject) {
// Set of values to be checked for their exact types.
SmallVector<SILValue, 8> WorkList;
// The detected type of the underlying object.
SILType ResultType;
// Set of processed values.
llvm::SmallSet<SILValue, 8> Processed;
WorkList.push_back(S);
while (!WorkList.empty()) {
auto V = WorkList.pop_back_val();
if (!V)
return SILType();
if (Processed.count(V))
continue;
Processed.insert(V);
// For underlying object strip casts and projections.
// For the object itself, simply strip casts.
V = ForUnderlyingObject ? getUnderlyingObject(V) : stripCasts(V);
if (isa<AllocRefInst>(V) || isa<MetatypeInst>(V)) {
if (ResultType && ResultType != V->getType())
return SILType();
ResultType = V->getType();
continue;
}
if (isa<LiteralInst>(V)) {
if (ResultType && ResultType != V->getType())
return SILType();
ResultType = V->getType();
continue;
}
if (isa<StructInst>(V) || isa<TupleInst>(V) || isa<EnumInst>(V)) {
if (ResultType && ResultType != V->getType())
return SILType();
ResultType = V->getType();
continue;
}
if (ForUnderlyingObject) {
if (isa<AllocationInst>(V)) {
if (ResultType && ResultType != V->getType())
return SILType();
ResultType = V->getType();
continue;
}
// Look through strong_pin instructions.
if (isa<StrongPinInst>(V)) {
WorkList.push_back(cast<SILInstruction>(V)->getOperand(0));
continue;
}
}
auto Arg = dyn_cast<SILArgument>(V);
if (!Arg) {
// We don't know what it is.
return SILType();
}
if (auto *FArg = dyn_cast<SILFunctionArgument>(Arg)) {
// Bail on metatypes for now.
if (FArg->getType().is<AnyMetatypeType>()) {
return SILType();
}
auto *CD = FArg->getType().getClassOrBoundGenericClass();
// If it is not class and it is a trivial type, then it
// should be the exact type.
if (!CD && FArg->getType().isTrivial(M)) {
if (ResultType && ResultType != FArg->getType())
return SILType();
ResultType = FArg->getType();
continue;
}
if (!CD) {
// It is not a class or a trivial type, so we don't know what it is.
return SILType();
}
// Check if this class is effectively final.
if (!isKnownFinalClass(CD, M, CHA)) {
return SILType();
}
if (ResultType && ResultType != FArg->getType())
return SILType();
ResultType = FArg->getType();
continue;
}
auto *SinglePred = Arg->getParent()->getSinglePredecessorBlock();
if (SinglePred) {
// If it is a BB argument received on a success branch
// of a checked_cast_br, then we know its exact type.
auto *CCBI = dyn_cast<CheckedCastBranchInst>(SinglePred->getTerminator());
if (CCBI && CCBI->isExact() && CCBI->getSuccessBB() == Arg->getParent()) {
if (ResultType && ResultType != Arg->getType())
return SILType();
ResultType = Arg->getType();
continue;
}
}
// It is a BB argument, look through incoming values. If they all have the
// same exact type, then we consider it to be the type of the BB argument.
SmallVector<SILValue, 4> IncomingValues;
if (Arg->getIncomingValues(IncomingValues)) {
for (auto InValue : IncomingValues) {
WorkList.push_back(InValue);
}
continue;
}
// The exact type is unknown.
return SILType();
}
return ResultType;
}
static bool markAliveBlocks(BasicBlock *BB,
SmallPtrSet<BasicBlock*, 128> &Reachable) {
SmallVector<BasicBlock*, 128> Worklist;
Worklist.push_back(BB);
bool Changed = false;
do {
BB = Worklist.pop_back_val();
if (!Reachable.insert(BB))
continue;
// Do a quick scan of the basic block, turning any obviously unreachable
// instructions into LLVM unreachable insts. The instruction combining pass
// canonicalizes unreachable insts into stores to null or undef.
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;++BBI){
if (CallInst *CI = dyn_cast<CallInst>(BBI)) {
if (CI->doesNotReturn()) {
// If we found a call to a no-return function, insert an unreachable
// instruction after it. Make sure there isn't *already* one there
// though.
++BBI;
if (!isa<UnreachableInst>(BBI)) {
// Don't insert a call to llvm.trap right before the unreachable.
changeToUnreachable(BBI, false);
Changed = true;
}
break;
}
}
// Store to undef and store to null are undefined and used to signal that
// they should be changed to unreachable by passes that can't modify the
// CFG.
if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) {
// Don't touch volatile stores.
if (SI->isVolatile()) continue;
Value *Ptr = SI->getOperand(1);
if (isa<UndefValue>(Ptr) ||
(isa<ConstantPointerNull>(Ptr) &&
SI->getPointerAddressSpace() == 0)) {
changeToUnreachable(SI, true);
Changed = true;
break;
}
}
}
// Turn invokes that call 'nounwind' functions into ordinary calls.
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
Value *Callee = II->getCalledValue();
if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
changeToUnreachable(II, true);
Changed = true;
} else if (II->doesNotThrow()) {
if (II->use_empty() && II->onlyReadsMemory()) {
// jump to the normal destination branch.
BranchInst::Create(II->getNormalDest(), II);
II->getUnwindDest()->removePredecessor(II->getParent());
II->eraseFromParent();
} else
changeToCall(II);
Changed = true;
}
}
Changed |= ConstantFoldTerminator(BB, true);
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
Worklist.push_back(*SI);
} while (!Worklist.empty());
return Changed;
}
/// Returns Attribute::None, Attribute::ReadOnly or Attribute::ReadNone.
static Attribute::AttrKind
determinePointerReadAttrs(Argument *A,
const SmallPtrSet<Argument *, 8> &SCCNodes) {
SmallVector<Use *, 32> Worklist;
SmallSet<Use *, 32> Visited;
// inalloca arguments are always clobbered by the call.
if (A->hasInAllocaAttr())
return Attribute::None;
bool IsRead = false;
// We don't need to track IsWritten. If A is written to, return immediately.
for (Use &U : A->uses()) {
Visited.insert(&U);
Worklist.push_back(&U);
}
while (!Worklist.empty()) {
Use *U = Worklist.pop_back_val();
Instruction *I = cast<Instruction>(U->getUser());
switch (I->getOpcode()) {
case Instruction::BitCast:
case Instruction::GetElementPtr:
case Instruction::PHI:
case Instruction::Select:
case Instruction::AddrSpaceCast:
// The original value is not read/written via this if the new value isn't.
for (Use &UU : I->uses())
if (Visited.insert(&UU).second)
Worklist.push_back(&UU);
break;
case Instruction::Call:
case Instruction::Invoke: {
bool Captures = true;
if (I->getType()->isVoidTy())
Captures = false;
auto AddUsersToWorklistIfCapturing = [&] {
if (Captures)
for (Use &UU : I->uses())
if (Visited.insert(&UU).second)
Worklist.push_back(&UU);
};
CallSite CS(I);
if (CS.doesNotAccessMemory()) {
AddUsersToWorklistIfCapturing();
continue;
}
Function *F = CS.getCalledFunction();
if (!F) {
if (CS.onlyReadsMemory()) {
IsRead = true;
AddUsersToWorklistIfCapturing();
continue;
}
return Attribute::None;
}
// Note: the callee and the two successor blocks *follow* the argument
// operands. This means there is no need to adjust UseIndex to account
// for these.
unsigned UseIndex = std::distance(CS.arg_begin(), U);
// U cannot be the callee operand use: since we're exploring the
// transitive uses of an Argument, having such a use be a callee would
// imply the CallSite is an indirect call or invoke; and we'd take the
// early exit above.
assert(UseIndex < CS.data_operands_size() &&
"Data operand use expected!");
bool IsOperandBundleUse = UseIndex >= CS.getNumArgOperands();
if (UseIndex >= F->arg_size() && !IsOperandBundleUse) {
assert(F->isVarArg() && "More params than args in non-varargs call");
return Attribute::None;
}
Captures &= !CS.doesNotCapture(UseIndex);
// Since the optimizer (by design) cannot see the data flow corresponding
// to a operand bundle use, these cannot participate in the optimistic SCC
// analysis. Instead, we model the operand bundle uses as arguments in
// call to a function external to the SCC.
if (!SCCNodes.count(&*std::next(F->arg_begin(), UseIndex)) ||
IsOperandBundleUse) {
// The accessors used on CallSite here do the right thing for calls and
// invokes with operand bundles.
if (!CS.onlyReadsMemory() && !CS.onlyReadsMemory(UseIndex))
return Attribute::None;
if (!CS.doesNotAccessMemory(UseIndex))
IsRead = true;
}
AddUsersToWorklistIfCapturing();
break;
}
case Instruction::Load:
IsRead = true;
break;
case Instruction::ICmp:
case Instruction::Ret:
break;
default:
return Attribute::None;
}
}
return IsRead ? Attribute::ReadOnly : Attribute::ReadNone;
}
// A soft instruction can be changed to work in other domains given by mask.
void ExeDepsFix::visitSoftInstr(MachineInstr *mi, unsigned mask) {
// Bitmask of available domains for this instruction after taking collapsed
// operands into account.
unsigned available = mask;
// Scan the explicit use operands for incoming domains.
SmallVector<int, 4> used;
if (LiveRegs)
for (unsigned i = mi->getDesc().getNumDefs(),
e = mi->getDesc().getNumOperands(); i != e; ++i) {
MachineOperand &mo = mi->getOperand(i);
if (!mo.isReg()) continue;
for (int rx : regIndizes(mo.getReg())) {
DomainValue *dv = LiveRegs[rx].Value;
if (dv == nullptr)
continue;
// Bitmask of domains that dv and available have in common.
unsigned common = dv->getCommonDomains(available);
// Is it possible to use this collapsed register for free?
if (dv->isCollapsed()) {
// Restrict available domains to the ones in common with the operand.
// If there are no common domains, we must pay the cross-domain
// penalty for this operand.
if (common) available = common;
} else if (common)
// Open DomainValue is compatible, save it for merging.
used.push_back(rx);
else
// Open DomainValue is not compatible with instruction. It is useless
// now.
kill(rx);
}
}
// If the collapsed operands force a single domain, propagate the collapse.
if (isPowerOf2_32(available)) {
unsigned domain = countTrailingZeros(available);
TII->setExecutionDomain(mi, domain);
visitHardInstr(mi, domain);
return;
}
// Kill off any remaining uses that don't match available, and build a list of
// incoming DomainValues that we want to merge.
SmallVector<LiveReg, 4> Regs;
for (SmallVectorImpl<int>::iterator i=used.begin(), e=used.end(); i!=e; ++i) {
int rx = *i;
assert(LiveRegs && "no space allocated for live registers");
const LiveReg &LR = LiveRegs[rx];
// This useless DomainValue could have been missed above.
if (!LR.Value->getCommonDomains(available)) {
kill(rx);
continue;
}
// Sorted insertion.
bool Inserted = false;
for (SmallVectorImpl<LiveReg>::iterator i = Regs.begin(), e = Regs.end();
i != e && !Inserted; ++i) {
if (LR.Def < i->Def) {
Inserted = true;
Regs.insert(i, LR);
}
}
if (!Inserted)
Regs.push_back(LR);
}
// doms are now sorted in order of appearance. Try to merge them all, giving
// priority to the latest ones.
DomainValue *dv = nullptr;
while (!Regs.empty()) {
if (!dv) {
dv = Regs.pop_back_val().Value;
// Force the first dv to match the current instruction.
dv->AvailableDomains = dv->getCommonDomains(available);
assert(dv->AvailableDomains && "Domain should have been filtered");
continue;
}
DomainValue *Latest = Regs.pop_back_val().Value;
// Skip already merged values.
if (Latest == dv || Latest->Next)
continue;
if (merge(dv, Latest))
continue;
// If latest didn't merge, it is useless now. Kill all registers using it.
for (int i : used) {
assert(LiveRegs && "no space allocated for live registers");
if (LiveRegs[i].Value == Latest)
kill(i);
}
}
// dv is the DomainValue we are going to use for this instruction.
if (!dv) {
dv = alloc();
dv->AvailableDomains = available;
}
dv->Instrs.push_back(mi);
// Finally set all defs and non-collapsed uses to dv. We must iterate through
// all the operators, including imp-def ones.
for (MachineInstr::mop_iterator ii = mi->operands_begin(),
ee = mi->operands_end();
ii != ee; ++ii) {
MachineOperand &mo = *ii;
if (!mo.isReg()) continue;
for (int rx : regIndizes(mo.getReg())) {
if (!LiveRegs[rx].Value || (mo.isDef() && LiveRegs[rx].Value != dv)) {
kill(rx);
setLiveReg(rx, dv);
}
}
}
}
MachineBasicBlock *
MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
// Splitting the critical edge to a landing pad block is non-trivial. Don't do
// it in this generic function.
if (Succ->isLandingPad())
return NULL;
MachineFunction *MF = getParent();
DebugLoc dl; // FIXME: this is nowhere
// We may need to update this's terminator, but we can't do that if
// AnalyzeBranch fails. If this uses a jump table, we won't touch it.
const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
MachineBasicBlock *TBB = 0, *FBB = 0;
SmallVector<MachineOperand, 4> Cond;
if (TII->AnalyzeBranch(*this, TBB, FBB, Cond))
return NULL;
// Avoid bugpoint weirdness: A block may end with a conditional branch but
// jumps to the same MBB is either case. We have duplicate CFG edges in that
// case that we can't handle. Since this never happens in properly optimized
// code, just skip those edges.
if (TBB && TBB == FBB) {
DEBUG(dbgs() << "Won't split critical edge after degenerate BB#"
<< getNumber() << '\n');
return NULL;
}
MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB);
DEBUG(dbgs() << "Splitting critical edge:"
" BB#" << getNumber()
<< " -- BB#" << NMBB->getNumber()
<< " -- BB#" << Succ->getNumber() << '\n');
LiveIntervals *LIS = P->getAnalysisIfAvailable<LiveIntervals>();
SlotIndexes *Indexes = P->getAnalysisIfAvailable<SlotIndexes>();
if (LIS)
LIS->insertMBBInMaps(NMBB);
else if (Indexes)
Indexes->insertMBBInMaps(NMBB);
// On some targets like Mips, branches may kill virtual registers. Make sure
// that LiveVariables is properly updated after updateTerminator replaces the
// terminators.
LiveVariables *LV = P->getAnalysisIfAvailable<LiveVariables>();
// Collect a list of virtual registers killed by the terminators.
SmallVector<unsigned, 4> KilledRegs;
if (LV)
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I) {
MachineInstr *MI = I;
for (MachineInstr::mop_iterator OI = MI->operands_begin(),
OE = MI->operands_end(); OI != OE; ++OI) {
if (!OI->isReg() || OI->getReg() == 0 ||
!OI->isUse() || !OI->isKill() || OI->isUndef())
continue;
unsigned Reg = OI->getReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
LV->getVarInfo(Reg).removeKill(MI)) {
KilledRegs.push_back(Reg);
DEBUG(dbgs() << "Removing terminator kill: " << *MI);
OI->setIsKill(false);
}
}
}
SmallVector<unsigned, 4> UsedRegs;
if (LIS) {
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I) {
MachineInstr *MI = I;
for (MachineInstr::mop_iterator OI = MI->operands_begin(),
OE = MI->operands_end(); OI != OE; ++OI) {
if (!OI->isReg() || OI->getReg() == 0)
continue;
unsigned Reg = OI->getReg();
if (std::find(UsedRegs.begin(), UsedRegs.end(), Reg) == UsedRegs.end())
UsedRegs.push_back(Reg);
}
}
}
ReplaceUsesOfBlockWith(Succ, NMBB);
// If updateTerminator() removes instructions, we need to remove them from
// SlotIndexes.
SmallVector<MachineInstr*, 4> Terminators;
if (Indexes) {
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I)
Terminators.push_back(I);
}
updateTerminator();
if (Indexes) {
SmallVector<MachineInstr*, 4> NewTerminators;
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I)
NewTerminators.push_back(I);
for (SmallVectorImpl<MachineInstr*>::iterator I = Terminators.begin(),
E = Terminators.end(); I != E; ++I) {
if (std::find(NewTerminators.begin(), NewTerminators.end(), *I) ==
NewTerminators.end())
Indexes->removeMachineInstrFromMaps(*I);
}
}
// Insert unconditional "jump Succ" instruction in NMBB if necessary.
NMBB->addSuccessor(Succ);
if (!NMBB->isLayoutSuccessor(Succ)) {
Cond.clear();
MF->getTarget().getInstrInfo()->InsertBranch(*NMBB, Succ, NULL, Cond, dl);
if (Indexes) {
for (instr_iterator I = NMBB->instr_begin(), E = NMBB->instr_end();
I != E; ++I) {
// Some instructions may have been moved to NMBB by updateTerminator(),
// so we first remove any instruction that already has an index.
if (Indexes->hasIndex(I))
Indexes->removeMachineInstrFromMaps(I);
Indexes->insertMachineInstrInMaps(I);
}
}
}
// Fix PHI nodes in Succ so they refer to NMBB instead of this
for (MachineBasicBlock::instr_iterator
i = Succ->instr_begin(),e = Succ->instr_end();
i != e && i->isPHI(); ++i)
for (unsigned ni = 1, ne = i->getNumOperands(); ni != ne; ni += 2)
if (i->getOperand(ni+1).getMBB() == this)
i->getOperand(ni+1).setMBB(NMBB);
// Inherit live-ins from the successor
for (MachineBasicBlock::livein_iterator I = Succ->livein_begin(),
E = Succ->livein_end(); I != E; ++I)
NMBB->addLiveIn(*I);
// Update LiveVariables.
const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
if (LV) {
// Restore kills of virtual registers that were killed by the terminators.
while (!KilledRegs.empty()) {
unsigned Reg = KilledRegs.pop_back_val();
for (instr_iterator I = instr_end(), E = instr_begin(); I != E;) {
if (!(--I)->addRegisterKilled(Reg, TRI, /* addIfNotFound= */ false))
continue;
if (TargetRegisterInfo::isVirtualRegister(Reg))
LV->getVarInfo(Reg).Kills.push_back(I);
DEBUG(dbgs() << "Restored terminator kill: " << *I);
break;
}
}
// Update relevant live-through information.
LV->addNewBlock(NMBB, this, Succ);
}
if (LIS) {
// After splitting the edge and updating SlotIndexes, live intervals may be
// in one of two situations, depending on whether this block was the last in
// the function. If the original block was the last in the function, all live
// intervals will end prior to the beginning of the new split block. If the
// original block was not at the end of the function, all live intervals will
// extend to the end of the new split block.
bool isLastMBB =
llvm::next(MachineFunction::iterator(NMBB)) == getParent()->end();
SlotIndex StartIndex = Indexes->getMBBEndIdx(this);
SlotIndex PrevIndex = StartIndex.getPrevSlot();
SlotIndex EndIndex = Indexes->getMBBEndIdx(NMBB);
// Find the registers used from NMBB in PHIs in Succ.
SmallSet<unsigned, 8> PHISrcRegs;
for (MachineBasicBlock::instr_iterator
I = Succ->instr_begin(), E = Succ->instr_end();
I != E && I->isPHI(); ++I) {
for (unsigned ni = 1, ne = I->getNumOperands(); ni != ne; ni += 2) {
if (I->getOperand(ni+1).getMBB() == NMBB) {
MachineOperand &MO = I->getOperand(ni);
unsigned Reg = MO.getReg();
PHISrcRegs.insert(Reg);
if (MO.isUndef())
continue;
LiveInterval &LI = LIS->getInterval(Reg);
VNInfo *VNI = LI.getVNInfoAt(PrevIndex);
assert(VNI && "PHI sources should be live out of their predecessors.");
LI.addRange(LiveRange(StartIndex, EndIndex, VNI));
}
}
}
MachineRegisterInfo *MRI = &getParent()->getRegInfo();
for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
if (PHISrcRegs.count(Reg) || !LIS->hasInterval(Reg))
continue;
LiveInterval &LI = LIS->getInterval(Reg);
if (!LI.liveAt(PrevIndex))
continue;
bool isLiveOut = LI.liveAt(LIS->getMBBStartIdx(Succ));
if (isLiveOut && isLastMBB) {
VNInfo *VNI = LI.getVNInfoAt(PrevIndex);
assert(VNI && "LiveInterval should have VNInfo where it is live.");
LI.addRange(LiveRange(StartIndex, EndIndex, VNI));
} else if (!isLiveOut && !isLastMBB) {
LI.removeRange(StartIndex, EndIndex);
}
}
// Update all intervals for registers whose uses may have been modified by
// updateTerminator().
LIS->repairIntervalsInRange(this, getFirstTerminator(), end(), UsedRegs);
}
if (MachineDominatorTree *MDT =
P->getAnalysisIfAvailable<MachineDominatorTree>()) {
// Update dominator information.
MachineDomTreeNode *SucccDTNode = MDT->getNode(Succ);
bool IsNewIDom = true;
for (const_pred_iterator PI = Succ->pred_begin(), E = Succ->pred_end();
PI != E; ++PI) {
MachineBasicBlock *PredBB = *PI;
if (PredBB == NMBB)
continue;
if (!MDT->dominates(SucccDTNode, MDT->getNode(PredBB))) {
IsNewIDom = false;
break;
}
}
// We know "this" dominates the newly created basic block.
MachineDomTreeNode *NewDTNode = MDT->addNewBlock(NMBB, this);
// If all the other predecessors of "Succ" are dominated by "Succ" itself
// then the new block is the new immediate dominator of "Succ". Otherwise,
// the new block doesn't dominate anything.
if (IsNewIDom)
MDT->changeImmediateDominator(SucccDTNode, NewDTNode);
}
if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
if (MachineLoop *TIL = MLI->getLoopFor(this)) {
// If one or the other blocks were not in a loop, the new block is not
// either, and thus LI doesn't need to be updated.
if (MachineLoop *DestLoop = MLI->getLoopFor(Succ)) {
if (TIL == DestLoop) {
// Both in the same loop, the NMBB joins loop.
DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
} else if (TIL->contains(DestLoop)) {
// Edge from an outer loop to an inner loop. Add to the outer loop.
TIL->addBasicBlockToLoop(NMBB, MLI->getBase());
} else if (DestLoop->contains(TIL)) {
// Edge from an inner loop to an outer loop. Add to the outer loop.
DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
} else {
// Edge from two loops with no containment relation. Because these
// are natural loops, we know that the destination block must be the
// header of its loop (adding a branch into a loop elsewhere would
// create an irreducible loop).
assert(DestLoop->getHeader() == Succ &&
"Should not create irreducible loops!");
if (MachineLoop *P = DestLoop->getParentLoop())
P->addBasicBlockToLoop(NMBB, MLI->getBase());
}
}
}
return NMBB;
}
// Builds the graph + StratifiedSets for a function.
CFLAAResult::FunctionInfo CFLAAResult::buildSetsFrom(Function *Fn) {
CFLGraphBuilder GraphBuilder(*this, TLI, *Fn);
StratifiedSetsBuilder<Value *> SetBuilder;
auto &Graph = GraphBuilder.getCFLGraph();
SmallVector<Value *, 16> Worklist;
for (auto Node : Graph.nodes())
Worklist.push_back(Node);
while (!Worklist.empty()) {
auto *CurValue = Worklist.pop_back_val();
SetBuilder.add(CurValue);
if (canSkipAddingToSets(CurValue))
continue;
auto Attr = Graph.attrFor(CurValue);
SetBuilder.noteAttributes(CurValue, Attr);
for (const auto &Edge : Graph.edgesFor(CurValue)) {
auto Label = Edge.Type;
auto *OtherValue = Edge.Other;
if (canSkipAddingToSets(OtherValue))
continue;
bool Added;
switch (directionOfEdgeType(Label)) {
case Level::Above:
Added = SetBuilder.addAbove(CurValue, OtherValue);
break;
case Level::Below:
Added = SetBuilder.addBelow(CurValue, OtherValue);
break;
case Level::Same:
Added = SetBuilder.addWith(CurValue, OtherValue);
break;
}
if (Added)
Worklist.push_back(OtherValue);
}
}
// Special handling for globals and arguments
for (auto *External : GraphBuilder.getExternalValues()) {
SetBuilder.add(External);
auto Attr = valueToAttr(External);
if (Attr.hasValue()) {
SetBuilder.noteAttributes(External, *Attr);
if (*Attr == AttrGlobal)
SetBuilder.addAttributesBelow(External, 1, AttrUnknown);
else
SetBuilder.addAttributesBelow(External, 1, AttrCaller);
}
}
// Special handling for interprocedural aliases
for (auto &Edge : GraphBuilder.getInterprocEdges()) {
auto FromVal = Edge.From.Val;
auto ToVal = Edge.To.Val;
SetBuilder.add(FromVal);
SetBuilder.add(ToVal);
SetBuilder.addBelowWith(FromVal, Edge.From.DerefLevel, ToVal,
Edge.To.DerefLevel);
}
// Special handling for interprocedural attributes
for (auto &IPAttr : GraphBuilder.getInterprocAttrs()) {
auto Val = IPAttr.Node.Val;
SetBuilder.add(Val);
SetBuilder.addAttributesBelow(Val, IPAttr.Node.DerefLevel, IPAttr.Attr);
}
// Special handling for opaque external functions
for (auto *Escape : GraphBuilder.getEscapedValues()) {
SetBuilder.add(Escape);
SetBuilder.noteAttributes(Escape, AttrEscaped);
SetBuilder.addAttributesBelow(Escape, 1, AttrUnknown);
}
return FunctionInfo(*Fn, GraphBuilder.getReturnValues(), SetBuilder.build());
}
void print(raw_ostream &OS, FuncIdConversionHelper &FN,
RootVector RootValues) {
// Go through each of the roots, and traverse the call stack, producing the
// aggregates as you go along. Remember these aggregates and stacks, and
// show summary statistics about:
//
// - Total number of unique stacks
// - Top 10 stacks by count
// - Top 10 stacks by aggregate duration
SmallVector<std::pair<const StackTrieNode *, uint64_t>, 11>
TopStacksByCount;
SmallVector<std::pair<const StackTrieNode *, uint64_t>, 11> TopStacksBySum;
auto greater_second =
[](const std::pair<const StackTrieNode *, uint64_t> &A,
const std::pair<const StackTrieNode *, uint64_t> &B) {
return A.second > B.second;
};
uint64_t UniqueStacks = 0;
for (const auto *N : RootValues) {
SmallVector<const StackTrieNode *, 16> S;
S.emplace_back(N);
while (!S.empty()) {
auto *Top = S.pop_back_val();
// We only start printing the stack (by walking up the parent pointers)
// when we get to a leaf function.
if (!Top->ExtraData.TerminalDurations.empty()) {
++UniqueStacks;
auto TopSum =
std::accumulate(Top->ExtraData.TerminalDurations.begin(),
Top->ExtraData.TerminalDurations.end(), 0uLL);
{
auto E = std::make_pair(Top, TopSum);
TopStacksBySum.insert(std::lower_bound(TopStacksBySum.begin(),
TopStacksBySum.end(), E,
greater_second),
E);
if (TopStacksBySum.size() == 11)
TopStacksBySum.pop_back();
}
{
auto E =
std::make_pair(Top, Top->ExtraData.TerminalDurations.size());
TopStacksByCount.insert(std::lower_bound(TopStacksByCount.begin(),
TopStacksByCount.end(), E,
greater_second),
E);
if (TopStacksByCount.size() == 11)
TopStacksByCount.pop_back();
}
}
for (const auto *C : Top->Callees)
S.push_back(C);
}
}
// Now print the statistics in the end.
OS << "\n";
OS << "Unique Stacks: " << UniqueStacks << "\n";
OS << "Top 10 Stacks by leaf sum:\n\n";
for (const auto &P : TopStacksBySum) {
OS << "Sum: " << P.second << "\n";
printStack(OS, P.first, FN);
}
OS << "\n";
OS << "Top 10 Stacks by leaf count:\n\n";
for (const auto &P : TopStacksByCount) {
OS << "Count: " << P.second << "\n";
printStack(OS, P.first, FN);
}
OS << "\n";
}
void llvm::PointerMayBeCaptured(const Value *V, CaptureTracker *Tracker) {
assert(V->getType()->isPointerTy() && "Capture is for pointers only!");
SmallVector<const Use *, Threshold> Worklist;
SmallSet<const Use *, Threshold> Visited;
int Count = 0;
for (const Use &U : V->uses()) {
// If there are lots of uses, conservatively say that the value
// is captured to avoid taking too much compile time.
if (Count++ >= Threshold)
return Tracker->tooManyUses();
if (!Tracker->shouldExplore(&U)) continue;
Visited.insert(&U);
Worklist.push_back(&U);
}
while (!Worklist.empty()) {
const Use *U = Worklist.pop_back_val();
Instruction *I = cast<Instruction>(U->getUser());
V = U->get();
switch (I->getOpcode()) {
case Instruction::Call:
case Instruction::Invoke: {
CallSite CS(I);
// Not captured if the callee is readonly, doesn't return a copy through
// its return value and doesn't unwind (a readonly function can leak bits
// by throwing an exception or not depending on the input value).
if (CS.onlyReadsMemory() && CS.doesNotThrow() && I->getType()->isVoidTy())
break;
// Volatile operations effectively capture the memory location that they
// load and store to.
if (auto *MI = dyn_cast<MemIntrinsic>(I))
if (MI->isVolatile())
if (Tracker->captured(U))
return;
// Not captured if only passed via 'nocapture' arguments. Note that
// calling a function pointer does not in itself cause the pointer to
// be captured. This is a subtle point considering that (for example)
// the callee might return its own address. It is analogous to saying
// that loading a value from a pointer does not cause the pointer to be
// captured, even though the loaded value might be the pointer itself
// (think of self-referential objects).
CallSite::data_operand_iterator B =
CS.data_operands_begin(), E = CS.data_operands_end();
for (CallSite::data_operand_iterator A = B; A != E; ++A)
if (A->get() == V && !CS.doesNotCapture(A - B))
// The parameter is not marked 'nocapture' - captured.
if (Tracker->captured(U))
return;
break;
}
case Instruction::Load:
// Volatile loads make the address observable.
if (cast<LoadInst>(I)->isVolatile())
if (Tracker->captured(U))
return;
break;
case Instruction::VAArg:
// "va-arg" from a pointer does not cause it to be captured.
break;
case Instruction::Store:
// Stored the pointer - conservatively assume it may be captured.
// Volatile stores make the address observable.
if (V == I->getOperand(0) || cast<StoreInst>(I)->isVolatile())
if (Tracker->captured(U))
return;
break;
case Instruction::AtomicRMW: {
// atomicrmw conceptually includes both a load and store from
// the same location.
// As with a store, the location being accessed is not captured,
// but the value being stored is.
// Volatile stores make the address observable.
auto *ARMWI = cast<AtomicRMWInst>(I);
if (ARMWI->getValOperand() == V || ARMWI->isVolatile())
if (Tracker->captured(U))
return;
break;
}
case Instruction::AtomicCmpXchg: {
// cmpxchg conceptually includes both a load and store from
// the same location.
// As with a store, the location being accessed is not captured,
// but the value being stored is.
// Volatile stores make the address observable.
auto *ACXI = cast<AtomicCmpXchgInst>(I);
if (ACXI->getCompareOperand() == V || ACXI->getNewValOperand() == V ||
ACXI->isVolatile())
if (Tracker->captured(U))
return;
break;
}
case Instruction::BitCast:
case Instruction::GetElementPtr:
case Instruction::PHI:
case Instruction::Select:
case Instruction::AddrSpaceCast:
// The original value is not captured via this if the new value isn't.
Count = 0;
for (Use &UU : I->uses()) {
// If there are lots of uses, conservatively say that the value
// is captured to avoid taking too much compile time.
if (Count++ >= Threshold)
return Tracker->tooManyUses();
if (Visited.insert(&UU).second)
if (Tracker->shouldExplore(&UU))
Worklist.push_back(&UU);
}
break;
case Instruction::ICmp: {
// Don't count comparisons of a no-alias return value against null as
// captures. This allows us to ignore comparisons of malloc results
// with null, for example.
if (ConstantPointerNull *CPN =
dyn_cast<ConstantPointerNull>(I->getOperand(1)))
if (CPN->getType()->getAddressSpace() == 0)
if (isNoAliasCall(V->stripPointerCasts()))
break;
// Comparison against value stored in global variable. Given the pointer
// does not escape, its value cannot be guessed and stored separately in a
// global variable.
unsigned OtherIndex = (I->getOperand(0) == V) ? 1 : 0;
auto *LI = dyn_cast<LoadInst>(I->getOperand(OtherIndex));
if (LI && isa<GlobalVariable>(LI->getPointerOperand()))
break;
// Otherwise, be conservative. There are crazy ways to capture pointers
// using comparisons.
if (Tracker->captured(U))
return;
break;
}
default:
// Something else - be conservative and say it is captured.
if (Tracker->captured(U))
return;
break;
}
}
// All uses examined.
}
/// Walk the specified loop in the CFG (defined by all blocks dominated by the
/// specified header block, and that are in the current loop) in depth first
/// order w.r.t the DominatorTree. This allows us to visit definitions before
/// uses, allowing us to hoist a loop body in one pass without iteration.
///
void MachineLICM::HoistOutOfLoop(MachineDomTreeNode *HeaderN) {
MachineBasicBlock *Preheader = getCurPreheader();
if (!Preheader)
return;
SmallVector<MachineDomTreeNode*, 32> Scopes;
SmallVector<MachineDomTreeNode*, 8> WorkList;
DenseMap<MachineDomTreeNode*, MachineDomTreeNode*> ParentMap;
DenseMap<MachineDomTreeNode*, unsigned> OpenChildren;
// Perform a DFS walk to determine the order of visit.
WorkList.push_back(HeaderN);
while (!WorkList.empty()) {
MachineDomTreeNode *Node = WorkList.pop_back_val();
assert(Node && "Null dominator tree node?");
MachineBasicBlock *BB = Node->getBlock();
// If the header of the loop containing this basic block is a landing pad,
// then don't try to hoist instructions out of this loop.
const MachineLoop *ML = MLI->getLoopFor(BB);
if (ML && ML->getHeader()->isEHPad())
continue;
// If this subregion is not in the top level loop at all, exit.
if (!CurLoop->contains(BB))
continue;
Scopes.push_back(Node);
const std::vector<MachineDomTreeNode*> &Children = Node->getChildren();
unsigned NumChildren = Children.size();
// Don't hoist things out of a large switch statement. This often causes
// code to be hoisted that wasn't going to be executed, and increases
// register pressure in a situation where it's likely to matter.
if (BB->succ_size() >= 25)
NumChildren = 0;
OpenChildren[Node] = NumChildren;
// Add children in reverse order as then the next popped worklist node is
// the first child of this node. This means we ultimately traverse the
// DOM tree in exactly the same order as if we'd recursed.
for (int i = (int)NumChildren-1; i >= 0; --i) {
MachineDomTreeNode *Child = Children[i];
ParentMap[Child] = Node;
WorkList.push_back(Child);
}
}
if (Scopes.size() == 0)
return;
// Compute registers which are livein into the loop headers.
RegSeen.clear();
BackTrace.clear();
InitRegPressure(Preheader);
// Now perform LICM.
for (MachineDomTreeNode *Node : Scopes) {
MachineBasicBlock *MBB = Node->getBlock();
EnterScope(MBB);
// Process the block
SpeculationState = SpeculateUnknown;
for (MachineBasicBlock::iterator
MII = MBB->begin(), E = MBB->end(); MII != E; ) {
MachineBasicBlock::iterator NextMII = MII; ++NextMII;
MachineInstr *MI = &*MII;
if (!Hoist(MI, Preheader))
UpdateRegPressure(MI);
MII = NextMII;
}
// If it's a leaf node, it's done. Traverse upwards to pop ancestors.
ExitScopeIfDone(Node, OpenChildren, ParentMap);
}
}
bool ObjCARCContract::runOnFunction(Function &F) {
if (!EnableARCOpts)
return false;
// If nothing in the Module uses ARC, don't do anything.
if (!Run)
return false;
Changed = false;
AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
PA.setAA(&getAnalysis<AAResultsWrapperPass>().getAAResults());
DenseMap<BasicBlock *, ColorVector> BlockColors;
if (F.hasPersonalityFn() &&
isScopedEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
BlockColors = colorEHFunclets(F);
LLVM_DEBUG(llvm::dbgs() << "**** ObjCARC Contract ****\n");
// Track whether it's ok to mark objc_storeStrong calls with the "tail"
// keyword. Be conservative if the function has variadic arguments.
// It seems that functions which "return twice" are also unsafe for the
// "tail" argument, because they are setjmp, which could need to
// return to an earlier stack state.
bool TailOkForStoreStrongs =
!F.isVarArg() && !F.callsFunctionThatReturnsTwice();
// For ObjC library calls which return their argument, replace uses of the
// argument with uses of the call return value, if it dominates the use. This
// reduces register pressure.
SmallPtrSet<Instruction *, 4> DependingInstructions;
SmallPtrSet<const BasicBlock *, 4> Visited;
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E;) {
Instruction *Inst = &*I++;
LLVM_DEBUG(dbgs() << "Visiting: " << *Inst << "\n");
// First try to peephole Inst. If there is nothing further we can do in
// terms of undoing objc-arc-expand, process the next inst.
if (tryToPeepholeInstruction(F, Inst, I, DependingInstructions, Visited,
TailOkForStoreStrongs, BlockColors))
continue;
// Otherwise, try to undo objc-arc-expand.
// Don't use GetArgRCIdentityRoot because we don't want to look through bitcasts
// and such; to do the replacement, the argument must have type i8*.
// Function for replacing uses of Arg dominated by Inst.
auto ReplaceArgUses = [Inst, this](Value *Arg) {
// If we're compiling bugpointed code, don't get in trouble.
if (!isa<Instruction>(Arg) && !isa<Argument>(Arg))
return;
// Look through the uses of the pointer.
for (Value::use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
UI != UE; ) {
// Increment UI now, because we may unlink its element.
Use &U = *UI++;
unsigned OperandNo = U.getOperandNo();
// If the call's return value dominates a use of the call's argument
// value, rewrite the use to use the return value. We check for
// reachability here because an unreachable call is considered to
// trivially dominate itself, which would lead us to rewriting its
// argument in terms of its return value, which would lead to
// infinite loops in GetArgRCIdentityRoot.
if (!DT->isReachableFromEntry(U) || !DT->dominates(Inst, U))
continue;
Changed = true;
Instruction *Replacement = Inst;
Type *UseTy = U.get()->getType();
if (PHINode *PHI = dyn_cast<PHINode>(U.getUser())) {
// For PHI nodes, insert the bitcast in the predecessor block.
unsigned ValNo = PHINode::getIncomingValueNumForOperand(OperandNo);
BasicBlock *IncomingBB = PHI->getIncomingBlock(ValNo);
if (Replacement->getType() != UseTy) {
// A catchswitch is both a pad and a terminator, meaning a basic
// block with a catchswitch has no insertion point. Keep going up
// the dominator tree until we find a non-catchswitch.
BasicBlock *InsertBB = IncomingBB;
while (isa<CatchSwitchInst>(InsertBB->getFirstNonPHI())) {
InsertBB = DT->getNode(InsertBB)->getIDom()->getBlock();
}
assert(DT->dominates(Inst, &InsertBB->back()) &&
"Invalid insertion point for bitcast");
Replacement =
new BitCastInst(Replacement, UseTy, "", &InsertBB->back());
}
// While we're here, rewrite all edges for this PHI, rather
// than just one use at a time, to minimize the number of
// bitcasts we emit.
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i)
if (PHI->getIncomingBlock(i) == IncomingBB) {
// Keep the UI iterator valid.
if (UI != UE &&
&PHI->getOperandUse(
PHINode::getOperandNumForIncomingValue(i)) == &*UI)
++UI;
PHI->setIncomingValue(i, Replacement);
}
} else {
if (Replacement->getType() != UseTy)
Replacement = new BitCastInst(Replacement, UseTy, "",
cast<Instruction>(U.getUser()));
U.set(Replacement);
}
}
};
Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
Value *OrigArg = Arg;
// TODO: Change this to a do-while.
for (;;) {
ReplaceArgUses(Arg);
// If Arg is a no-op casted pointer, strip one level of casts and iterate.
if (const BitCastInst *BI = dyn_cast<BitCastInst>(Arg))
Arg = BI->getOperand(0);
else if (isa<GEPOperator>(Arg) &&
cast<GEPOperator>(Arg)->hasAllZeroIndices())
Arg = cast<GEPOperator>(Arg)->getPointerOperand();
else if (isa<GlobalAlias>(Arg) &&
!cast<GlobalAlias>(Arg)->isInterposable())
Arg = cast<GlobalAlias>(Arg)->getAliasee();
else {
// If Arg is a PHI node, get PHIs that are equivalent to it and replace
// their uses.
if (PHINode *PN = dyn_cast<PHINode>(Arg)) {
SmallVector<Value *, 1> PHIList;
getEquivalentPHIs(*PN, PHIList);
for (Value *PHI : PHIList)
ReplaceArgUses(PHI);
}
break;
}
}
// Replace bitcast users of Arg that are dominated by Inst.
SmallVector<BitCastInst *, 2> BitCastUsers;
// Add all bitcast users of the function argument first.
for (User *U : OrigArg->users())
if (auto *BC = dyn_cast<BitCastInst>(U))
BitCastUsers.push_back(BC);
// Replace the bitcasts with the call return. Iterate until list is empty.
while (!BitCastUsers.empty()) {
auto *BC = BitCastUsers.pop_back_val();
for (User *U : BC->users())
if (auto *B = dyn_cast<BitCastInst>(U))
BitCastUsers.push_back(B);
ReplaceArgUses(BC);
}
}
// If this function has no escaping allocas or suspicious vararg usage,
// objc_storeStrong calls can be marked with the "tail" keyword.
if (TailOkForStoreStrongs)
for (CallInst *CI : StoreStrongCalls)
CI->setTailCall();
StoreStrongCalls.clear();
return Changed;
}
const CodeGenRegister::SubRegMap &
CodeGenRegister::getSubRegs(CodeGenRegBank &RegBank) {
// Only compute this map once.
if (SubRegsComplete)
return SubRegs;
SubRegsComplete = true;
std::vector<Record*> SubList = TheDef->getValueAsListOfDefs("SubRegs");
std::vector<Record*> IdxList = TheDef->getValueAsListOfDefs("SubRegIndices");
if (SubList.size() != IdxList.size())
throw TGError(TheDef->getLoc(), "Register " + getName() +
" SubRegIndices doesn't match SubRegs");
// First insert the direct subregs and make sure they are fully indexed.
SmallVector<CodeGenSubRegIndex*, 8> Indices;
for (unsigned i = 0, e = SubList.size(); i != e; ++i) {
CodeGenRegister *SR = RegBank.getReg(SubList[i]);
CodeGenSubRegIndex *Idx = RegBank.getSubRegIdx(IdxList[i]);
Indices.push_back(Idx);
if (!SubRegs.insert(std::make_pair(Idx, SR)).second)
throw TGError(TheDef->getLoc(), "SubRegIndex " + Idx->getName() +
" appears twice in Register " + getName());
}
// Keep track of inherited subregs and how they can be reached.
SmallPtrSet<CodeGenRegister*, 8> Orphans;
// Clone inherited subregs and place duplicate entries in Orphans.
// Here the order is important - earlier subregs take precedence.
for (unsigned i = 0, e = SubList.size(); i != e; ++i) {
CodeGenRegister *SR = RegBank.getReg(SubList[i]);
const SubRegMap &Map = SR->getSubRegs(RegBank);
// Add this as a super-register of SR now all sub-registers are in the list.
// This creates a topological ordering, the exact order depends on the
// order getSubRegs is called on all registers.
SR->SuperRegs.push_back(this);
for (SubRegMap::const_iterator SI = Map.begin(), SE = Map.end(); SI != SE;
++SI) {
if (!SubRegs.insert(*SI).second)
Orphans.insert(SI->second);
// Noop sub-register indexes are possible, so avoid duplicates.
if (SI->second != SR)
SI->second->SuperRegs.push_back(this);
}
}
// Expand any composed subreg indices.
// If dsub_2 has ComposedOf = [qsub_1, dsub_0], and this register has a
// qsub_1 subreg, add a dsub_2 subreg. Keep growing Indices and process
// expanded subreg indices recursively.
for (unsigned i = 0; i != Indices.size(); ++i) {
CodeGenSubRegIndex *Idx = Indices[i];
const CodeGenSubRegIndex::CompMap &Comps = Idx->getComposites();
CodeGenRegister *SR = SubRegs[Idx];
const SubRegMap &Map = SR->getSubRegs(RegBank);
// Look at the possible compositions of Idx.
// They may not all be supported by SR.
for (CodeGenSubRegIndex::CompMap::const_iterator I = Comps.begin(),
E = Comps.end(); I != E; ++I) {
SubRegMap::const_iterator SRI = Map.find(I->first);
if (SRI == Map.end())
continue; // Idx + I->first doesn't exist in SR.
// Add I->second as a name for the subreg SRI->second, assuming it is
// orphaned, and the name isn't already used for something else.
if (SubRegs.count(I->second) || !Orphans.erase(SRI->second))
continue;
// We found a new name for the orphaned sub-register.
SubRegs.insert(std::make_pair(I->second, SRI->second));
Indices.push_back(I->second);
}
}
// Process the composites.
ListInit *Comps = TheDef->getValueAsListInit("CompositeIndices");
for (unsigned i = 0, e = Comps->size(); i != e; ++i) {
DagInit *Pat = dynamic_cast<DagInit*>(Comps->getElement(i));
if (!Pat)
throw TGError(TheDef->getLoc(), "Invalid dag '" +
Comps->getElement(i)->getAsString() +
"' in CompositeIndices");
DefInit *BaseIdxInit = dynamic_cast<DefInit*>(Pat->getOperator());
if (!BaseIdxInit || !BaseIdxInit->getDef()->isSubClassOf("SubRegIndex"))
throw TGError(TheDef->getLoc(), "Invalid SubClassIndex in " +
Pat->getAsString());
CodeGenSubRegIndex *BaseIdx = RegBank.getSubRegIdx(BaseIdxInit->getDef());
// Resolve list of subreg indices into R2.
CodeGenRegister *R2 = this;
for (DagInit::const_arg_iterator di = Pat->arg_begin(),
de = Pat->arg_end(); di != de; ++di) {
DefInit *IdxInit = dynamic_cast<DefInit*>(*di);
if (!IdxInit || !IdxInit->getDef()->isSubClassOf("SubRegIndex"))
throw TGError(TheDef->getLoc(), "Invalid SubClassIndex in " +
Pat->getAsString());
CodeGenSubRegIndex *Idx = RegBank.getSubRegIdx(IdxInit->getDef());
const SubRegMap &R2Subs = R2->getSubRegs(RegBank);
SubRegMap::const_iterator ni = R2Subs.find(Idx);
if (ni == R2Subs.end())
throw TGError(TheDef->getLoc(), "Composite " + Pat->getAsString() +
" refers to bad index in " + R2->getName());
R2 = ni->second;
}
// Insert composite index. Allow overriding inherited indices etc.
SubRegs[BaseIdx] = R2;
// R2 is no longer an orphan.
Orphans.erase(R2);
}
// Now Orphans contains the inherited subregisters without a direct index.
// Create inferred indexes for all missing entries.
// Work backwards in the Indices vector in order to compose subregs bottom-up.
// Consider this subreg sequence:
//
// qsub_1 -> dsub_0 -> ssub_0
//
// The qsub_1 -> dsub_0 composition becomes dsub_2, so the ssub_0 register
// can be reached in two different ways:
//
// qsub_1 -> ssub_0
// dsub_2 -> ssub_0
//
// We pick the latter composition because another register may have [dsub_0,
// dsub_1, dsub_2] subregs without neccessarily having a qsub_1 subreg. The
// dsub_2 -> ssub_0 composition can be shared.
while (!Indices.empty() && !Orphans.empty()) {
CodeGenSubRegIndex *Idx = Indices.pop_back_val();
CodeGenRegister *SR = SubRegs[Idx];
const SubRegMap &Map = SR->getSubRegs(RegBank);
for (SubRegMap::const_iterator SI = Map.begin(), SE = Map.end(); SI != SE;
++SI)
if (Orphans.erase(SI->second))
SubRegs[RegBank.getCompositeSubRegIndex(Idx, SI->first)] = SI->second;
}
// Initialize RegUnitList. A register with no subregisters creates its own
// unit. Otherwise, it inherits all its subregister's units. Because
// getSubRegs is called recursively, this processes the register hierarchy in
// postorder.
//
// TODO: We currently assume all register units correspond to a named "leaf"
// register. We should also unify register units for ad-hoc register
// aliases. This can be done by iteratively merging units for aliasing
// registers using a worklist.
assert(RegUnits.empty() && "Should only initialize RegUnits once");
if (SubRegs.empty()) {
RegUnits.push_back(RegBank.newRegUnit());
}
else {
for (SubRegMap::const_iterator I = SubRegs.begin(), E = SubRegs.end();
I != E; ++I) {
// Strangely a register may have itself as a subreg (self-cycle) e.g. XMM.
CodeGenRegister *SR = I->second;
if (SR == this) {
if (RegUnits.empty())
RegUnits.push_back(RegBank.newRegUnit());
continue;
}
// Merge the subregister's units into this register's RegUnits.
mergeRegUnits(RegUnits, SR->RegUnits);
}
}
return SubRegs;
}
// Builds the graph + StratifiedSets for a function.
CFLAAResult::FunctionInfo CFLAAResult::buildSetsFrom(Function *Fn) {
NodeMapT Map;
GraphT Graph;
SmallVector<Value *, 4> ReturnedValues;
buildGraphFrom(*this, Fn, ReturnedValues, Map, Graph);
DenseMap<GraphT::Node, Value *> NodeValueMap;
NodeValueMap.reserve(Map.size());
for (const auto &Pair : Map)
NodeValueMap.insert(std::make_pair(Pair.second, Pair.first));
const auto findValueOrDie = [&NodeValueMap](GraphT::Node Node) {
auto ValIter = NodeValueMap.find(Node);
assert(ValIter != NodeValueMap.end());
return ValIter->second;
};
StratifiedSetsBuilder<Value *> Builder;
SmallVector<GraphT::Node, 16> Worklist;
for (auto &Pair : Map) {
Worklist.clear();
auto *Value = Pair.first;
Builder.add(Value);
auto InitialNode = Pair.second;
Worklist.push_back(InitialNode);
while (!Worklist.empty()) {
auto Node = Worklist.pop_back_val();
auto *CurValue = findValueOrDie(Node);
if (canSkipAddingToSets(CurValue))
continue;
Optional<StratifiedAttr> MaybeCurIndex = valueToAttrIndex(CurValue);
if (MaybeCurIndex)
Builder.noteAttributes(CurValue, *MaybeCurIndex);
for (const auto &EdgeTuple : Graph.edgesFor(Node)) {
auto Weight = std::get<0>(EdgeTuple);
auto Label = Weight.first;
auto &OtherNode = std::get<1>(EdgeTuple);
auto *OtherValue = findValueOrDie(OtherNode);
if (canSkipAddingToSets(OtherValue))
continue;
bool Added;
switch (directionOfEdgeType(Label)) {
case Level::Above:
Added = Builder.addAbove(CurValue, OtherValue);
break;
case Level::Below:
Added = Builder.addBelow(CurValue, OtherValue);
break;
case Level::Same:
Added = Builder.addWith(CurValue, OtherValue);
break;
}
auto Aliasing = Weight.second;
if (MaybeCurIndex)
Aliasing.set(*MaybeCurIndex);
if (auto MaybeOtherIndex = valueToAttrIndex(OtherValue))
Aliasing.set(*MaybeOtherIndex);
Builder.noteAttributes(CurValue, Aliasing);
Builder.noteAttributes(OtherValue, Aliasing);
if (Added)
Worklist.push_back(OtherNode);
}
}
}
// There are times when we end up with parameters not in our graph (i.e. if
// it's only used as the condition of a branch). Other bits of code depend on
// things that were present during construction being present in the graph.
// So, we add all present arguments here.
for (auto &Arg : Fn->args()) {
if (!Builder.add(&Arg))
continue;
auto Attrs = valueToAttrIndex(&Arg);
if (Attrs.hasValue())
Builder.noteAttributes(&Arg, *Attrs);
}
return FunctionInfo(Builder.build(), std::move(ReturnedValues));
}
/// isOnlyCopiedFromConstantGlobal - Recursively walk the uses of a (derived)
/// pointer to an alloca. Ignore any reads of the pointer, return false if we
/// see any stores or other unknown uses. If we see pointer arithmetic, keep
/// track of whether it moves the pointer (with IsOffset) but otherwise traverse
/// the uses. If we see a memcpy/memmove that targets an unoffseted pointer to
/// the alloca, and if the source pointer is a pointer to a constant global, we
/// can optimize this.
static bool
isOnlyCopiedFromConstantGlobal(Value *V, MemTransferInst *&TheCopy,
SmallVectorImpl<Instruction *> &ToDelete) {
// We track lifetime intrinsics as we encounter them. If we decide to go
// ahead and replace the value with the global, this lets the caller quickly
// eliminate the markers.
SmallVector<std::pair<Value *, bool>, 35> ValuesToInspect;
ValuesToInspect.push_back(std::make_pair(V, false));
while (!ValuesToInspect.empty()) {
auto ValuePair = ValuesToInspect.pop_back_val();
const bool IsOffset = ValuePair.second;
for (auto &U : ValuePair.first->uses()) {
Instruction *I = cast<Instruction>(U.getUser());
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
// Ignore non-volatile loads, they are always ok.
if (!LI->isSimple()) return false;
continue;
}
if (isa<BitCastInst>(I) || isa<AddrSpaceCastInst>(I)) {
// If uses of the bitcast are ok, we are ok.
ValuesToInspect.push_back(std::make_pair(I, IsOffset));
continue;
}
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
// If the GEP has all zero indices, it doesn't offset the pointer. If it
// doesn't, it does.
ValuesToInspect.push_back(
std::make_pair(I, IsOffset || !GEP->hasAllZeroIndices()));
continue;
}
if (auto CS = CallSite(I)) {
// If this is the function being called then we treat it like a load and
// ignore it.
if (CS.isCallee(&U))
continue;
unsigned DataOpNo = CS.getDataOperandNo(&U);
bool IsArgOperand = CS.isArgOperand(&U);
// Inalloca arguments are clobbered by the call.
if (IsArgOperand && CS.isInAllocaArgument(DataOpNo))
return false;
// If this is a readonly/readnone call site, then we know it is just a
// load (but one that potentially returns the value itself), so we can
// ignore it if we know that the value isn't captured.
if (CS.onlyReadsMemory() &&
(CS.getInstruction()->use_empty() || CS.doesNotCapture(DataOpNo)))
continue;
// If this is being passed as a byval argument, the caller is making a
// copy, so it is only a read of the alloca.
if (IsArgOperand && CS.isByValArgument(DataOpNo))
continue;
}
// Lifetime intrinsics can be handled by the caller.
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
II->getIntrinsicID() == Intrinsic::lifetime_end) {
assert(II->use_empty() && "Lifetime markers have no result to use!");
ToDelete.push_back(II);
continue;
}
}
// If this is isn't our memcpy/memmove, reject it as something we can't
// handle.
MemTransferInst *MI = dyn_cast<MemTransferInst>(I);
if (!MI)
return false;
// If the transfer is using the alloca as a source of the transfer, then
// ignore it since it is a load (unless the transfer is volatile).
if (U.getOperandNo() == 1) {
if (MI->isVolatile()) return false;
continue;
}
// If we already have seen a copy, reject the second one.
if (TheCopy) return false;
// If the pointer has been offset from the start of the alloca, we can't
// safely handle this.
if (IsOffset) return false;
// If the memintrinsic isn't using the alloca as the dest, reject it.
if (U.getOperandNo() != 0) return false;
// If the source of the memcpy/move is not a constant global, reject it.
if (!pointsToConstantGlobal(MI->getSource()))
return false;
// Otherwise, the transform is safe. Remember the copy instruction.
TheCopy = MI;
}
}
return true;
}
static bool verifyCTRBranch(MachineBasicBlock *MBB,
MachineBasicBlock::iterator I) {
MachineBasicBlock::iterator BI = I;
SmallSet<MachineBasicBlock *, 16> Visited;
SmallVector<MachineBasicBlock *, 8> Preds;
bool CheckPreds;
if (I == MBB->begin()) {
Visited.insert(MBB);
goto queue_preds;
} else
--I;
check_block:
Visited.insert(MBB);
if (I == MBB->end())
goto queue_preds;
CheckPreds = true;
for (MachineBasicBlock::iterator IE = MBB->begin();; --I) {
unsigned Opc = I->getOpcode();
if (Opc == PPC::MTCTRloop || Opc == PPC::MTCTR8loop) {
CheckPreds = false;
break;
}
if (I != BI && clobbersCTR(I)) {
DEBUG(dbgs() << "BB#" << MBB->getNumber() << " (" <<
MBB->getFullName() << ") instruction " << *I <<
" clobbers CTR, invalidating " << "BB#" <<
BI->getParent()->getNumber() << " (" <<
BI->getParent()->getFullName() << ") instruction " <<
*BI << "\n");
return false;
}
if (I == IE)
break;
}
if (!CheckPreds && Preds.empty())
return true;
if (CheckPreds) {
queue_preds:
if (MachineFunction::iterator(MBB) == MBB->getParent()->begin()) {
DEBUG(dbgs() << "Unable to find a MTCTR instruction for BB#" <<
BI->getParent()->getNumber() << " (" <<
BI->getParent()->getFullName() << ") instruction " <<
*BI << "\n");
return false;
}
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
PIE = MBB->pred_end(); PI != PIE; ++PI)
Preds.push_back(*PI);
}
do {
MBB = Preds.pop_back_val();
if (!Visited.count(MBB)) {
I = MBB->getLastNonDebugInstr();
goto check_block;
}
} while (!Preds.empty());
return true;
}
/// performStoreOnlyObjectElimination - Scan the graph of uses of the specified
/// object allocation. If the object does not escape and is only stored to
/// (this happens because GVN and other optimizations hoists forward substitutes
/// all stores to the object to eliminate all loads from it), then zap the
/// object and all accesses related to it.
static bool performStoreOnlyObjectElimination(CallInst &Allocation,
BasicBlock::iterator &BBI) {
DtorKind DtorInfo = analyzeDestructor(Allocation.getArgOperand(0));
// We can't delete the object if its destructor has side effects.
if (DtorInfo != DtorKind::NoSideEffects)
return false;
// Do a depth first search exploring all of the uses of the object pointer,
// following through casts, pointer adjustments etc. If we find any loads or
// any escape sites of the object, we give up. If we succeed in walking the
// entire graph of uses, we can remove the resultant set.
SmallSetVector<Instruction*, 16> InvolvedInstructions;
SmallVector<Instruction*, 16> Worklist;
Worklist.push_back(&Allocation);
// Stores - Keep track of all of the store instructions we see.
SmallVector<StoreInst*, 16> Stores;
while (!Worklist.empty()) {
Instruction *I = Worklist.pop_back_val();
// Insert the instruction into our InvolvedInstructions set. If we have
// already seen it, then don't reprocess all of the uses.
if (!InvolvedInstructions.insert(I)) continue;
// Okay, this is the first time we've seen this instruction, proceed.
switch (classifyInstruction(*I)) {
// These instructions should not reach here based on the pass ordering.
// i.e. LLVMARCOpt -> LLVMContractOpt.
case RT_RetainN:
case RT_UnknownRetainN:
case RT_BridgeRetainN:
case RT_ReleaseN:
case RT_UnknownReleaseN:
case RT_BridgeReleaseN:
llvm_unreachable("These are only created by LLVMARCContract !");
case RT_AllocObject:
// If this is a different swift_allocObject than we started with, then
// there is some computation feeding into a size or alignment computation
// that we have to keep... unless we can delete *that* entire object as
// well.
break;
case RT_NoMemoryAccessed:
// If no memory is accessed, then something is being done with the
// pointer: maybe it is bitcast or GEP'd. Since there are no side effects,
// it is perfectly fine to delete this instruction if all uses of the
// instruction are also eliminable.
if (I->mayHaveSideEffects() || isa<TerminatorInst>(I))
return false;
break;
case RT_Release:
case RT_Retain:
case RT_FixLifetime:
case RT_CheckUnowned:
// It is perfectly fine to eliminate various retains and releases of this
// object: we are zapping all accesses or none.
break;
// If this is an unknown instruction, we have more interesting things to
// consider.
case RT_Unknown:
case RT_ObjCRelease:
case RT_ObjCRetain:
case RT_UnknownRetain:
case RT_UnknownRelease:
case RT_BridgeRetain:
case RT_BridgeRelease:
case RT_RetainUnowned:
// Otherwise, this really is some unhandled instruction. Bail out.
return false;
}
// Okay, if we got here, the instruction can be eaten so-long as all of its
// uses can be. Scan through the uses and add them to the worklist for
// recursive processing.
for (auto UI = I->user_begin(), E = I->user_end(); UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
// Handle stores as a special case here: we want to make sure that the
// object is being stored *to*, not itself being stored (which would be an
// escape point). Since stores themselves don't have any uses, we can
// short-cut the classification scheme above.
if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
// If this is a store *to* the object, we can zap it.
if (UI.getUse().getOperandNo() == StoreInst::getPointerOperandIndex()) {
InvolvedInstructions.insert(SI);
continue;
}
// Otherwise, using the object as a source (or size) is an escape.
return false;
}
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(User)) {
// If this is a memset/memcpy/memmove *to* the object, we can zap it.
if (UI.getUse().getOperandNo() == 0) {
InvolvedInstructions.insert(MI);
continue;
}
// Otherwise, using the object as a source (or size) is an escape.
return false;
}
// Otherwise, normal instructions just go on the worklist for processing.
Worklist.push_back(User);
}
}
// Ok, we succeeded! This means we can zap all of the instructions that use
// the object. One thing we have to be careful of is to make sure that we
// don't invalidate "BBI" (the iterator the outer walk of the optimization
// pass is using, and indicates the next instruction to process). This would
// happen if we delete the instruction it is pointing to. Advance the
// iterator if that would happen.
while (InvolvedInstructions.count(&*BBI))
++BBI;
// Zap all of the instructions.
for (auto I : InvolvedInstructions) {
if (!I->use_empty())
I->replaceAllUsesWith(UndefValue::get(I->getType()));
I->eraseFromParent();
}
++NumStoreOnlyObjectsEliminated;
return true;
}
void swift::ide::printSubmoduleInterface(
Module *M,
ArrayRef<StringRef> FullModuleName,
ArrayRef<StringRef> GroupNames,
ModuleTraversalOptions TraversalOptions,
ASTPrinter &Printer,
const PrintOptions &Options,
const bool PrintSynthesizedExtensions) {
auto AdjustedOptions = Options;
adjustPrintOptions(AdjustedOptions);
SmallVector<Decl *, 1> Decls;
M->getDisplayDecls(Decls);
auto &SwiftContext = M->getASTContext();
auto &Importer =
static_cast<ClangImporter &>(*SwiftContext.getClangModuleLoader());
const clang::Module *InterestingClangModule = nullptr;
SmallVector<ImportDecl *, 1> ImportDecls;
llvm::DenseSet<const clang::Module *> ClangModulesForImports;
SmallVector<Decl *, 1> SwiftDecls;
llvm::DenseMap<const clang::Module *,
SmallVector<std::pair<Decl *, clang::SourceLocation>, 1>>
ClangDecls;
// Drop top-level module name.
FullModuleName = FullModuleName.slice(1);
InterestingClangModule = M->findUnderlyingClangModule();
if (InterestingClangModule) {
for (StringRef Name : FullModuleName) {
InterestingClangModule = InterestingClangModule->findSubmodule(Name);
if (!InterestingClangModule)
return;
}
} else {
assert(FullModuleName.empty());
}
// If we're printing recursively, find all of the submodules to print.
if (InterestingClangModule) {
if (TraversalOptions) {
SmallVector<const clang::Module *, 8> Worklist;
SmallPtrSet<const clang::Module *, 8> Visited;
Worklist.push_back(InterestingClangModule);
Visited.insert(InterestingClangModule);
while (!Worklist.empty()) {
const clang::Module *CM = Worklist.pop_back_val();
if (!(TraversalOptions & ModuleTraversal::VisitHidden) &&
CM->IsExplicit)
continue;
ClangDecls.insert({ CM, {} });
// If we're supposed to visit submodules, add them now.
if (TraversalOptions & ModuleTraversal::VisitSubmodules) {
for (auto Sub = CM->submodule_begin(), SubEnd = CM->submodule_end();
Sub != SubEnd; ++Sub) {
if (Visited.insert(*Sub).second)
Worklist.push_back(*Sub);
}
}
}
} else {
ClangDecls.insert({ InterestingClangModule, {} });
}
}
// Collect those submodules that are actually imported but have no import decls
// in the module.
llvm::SmallPtrSet<const clang::Module *, 16> NoImportSubModules;
if (InterestingClangModule) {
// Assume all submodules are missing.
for (auto It =InterestingClangModule->submodule_begin();
It != InterestingClangModule->submodule_end(); It ++) {
NoImportSubModules.insert(*It);
}
}
llvm::StringMap<std::vector<Decl*>> FileRangedDecls;
// Separate the declarations that we are going to print into different
// buckets.
for (Decl *D : Decls) {
// Skip declarations that are not accessible.
if (auto *VD = dyn_cast<ValueDecl>(D)) {
if (Options.AccessibilityFilter > Accessibility::Private &&
VD->hasAccessibility() &&
VD->getFormalAccess() < Options.AccessibilityFilter)
continue;
}
auto ShouldPrintImport = [&](ImportDecl *ImportD) -> bool {
if (!InterestingClangModule)
return true;
auto ClangMod = ImportD->getClangModule();
if (!ClangMod)
return true;
if (!ClangMod->isSubModule())
return true;
if (ClangMod == InterestingClangModule)
return false;
// FIXME: const-ness on the clang API.
return ClangMod->isSubModuleOf(
const_cast<clang::Module*>(InterestingClangModule));
};
if (auto ID = dyn_cast<ImportDecl>(D)) {
if (ShouldPrintImport(ID)) {
if (ID->getClangModule())
// Erase those submodules that are not missing.
NoImportSubModules.erase(ID->getClangModule());
if (ID->getImportKind() == ImportKind::Module) {
// Make sure we don't print duplicate imports, due to getting imports
// for both a clang module and its overlay.
if (auto *ClangMod = getUnderlyingClangModuleForImport(ID)) {
auto P = ClangModulesForImports.insert(ClangMod);
bool IsNew = P.second;
if (!IsNew)
continue;
}
}
ImportDecls.push_back(ID);
}
continue;
}
auto addToClangDecls = [&](Decl *D) {
assert(D->hasClangNode());
auto CN = D->getClangNode();
clang::SourceLocation Loc = CN.getLocation();
auto *OwningModule = Importer.getClangOwningModule(CN);
auto I = ClangDecls.find(OwningModule);
if (I != ClangDecls.end()) {
I->second.push_back({ D, Loc });
}
};
if (D->hasClangNode()) {
addToClangDecls(D);
continue;
}
if (FullModuleName.empty()) {
// If group name is given and the decl does not belong to the group, skip it.
if (!GroupNames.empty()){
if (auto Target = D->getGroupName()) {
if (std::find(GroupNames.begin(), GroupNames.end(),
Target.getValue()) != GroupNames.end()) {
FileRangedDecls.insert(std::make_pair(D->getSourceFileName().getValue(),
std::vector<Decl*>())).first->getValue().push_back(D);
}
}
continue;
}
// Add Swift decls if we are printing the top-level module.
SwiftDecls.push_back(D);
}
}
if (!GroupNames.empty()) {
assert(SwiftDecls.empty());
for (auto &Entry : FileRangedDecls) {
auto &DeclsInFile = Entry.getValue();
std::sort(DeclsInFile.begin(), DeclsInFile.end(),
[](Decl* LHS, Decl *RHS) {
assert(LHS->getSourceOrder().hasValue());
assert(RHS->getSourceOrder().hasValue());
return LHS->getSourceOrder().getValue() <
RHS->getSourceOrder().getValue();
});
for (auto D : DeclsInFile) {
SwiftDecls.push_back(D);
}
}
}
// Create the missing import decls and add to the collector.
for (auto *SM : NoImportSubModules) {
ImportDecls.push_back(createImportDecl(M->getASTContext(), M, SM, {}));
}
auto &ClangSourceManager = Importer.getClangASTContext().getSourceManager();
// Sort imported declarations in source order *within a submodule*.
for (auto &P : ClangDecls) {
std::sort(P.second.begin(), P.second.end(),
[&](std::pair<Decl *, clang::SourceLocation> LHS,
std::pair<Decl *, clang::SourceLocation> RHS) -> bool {
return ClangSourceManager.isBeforeInTranslationUnit(LHS.second,
RHS.second);
});
}
// Sort Swift declarations so that we print them in a consistent order.
std::sort(ImportDecls.begin(), ImportDecls.end(),
[](ImportDecl *LHS, ImportDecl *RHS) -> bool {
auto LHSPath = LHS->getFullAccessPath();
auto RHSPath = RHS->getFullAccessPath();
for (unsigned i = 0, e = std::min(LHSPath.size(), RHSPath.size()); i != e;
i++) {
if (int Ret = LHSPath[i].first.str().compare(RHSPath[i].first.str()))
return Ret < 0;
}
return false;
});
// If the group name is specified, we sort them according to their source order,
// which is the order preserved by getTopLeveDecls.
if (GroupNames.empty()) {
std::sort(SwiftDecls.begin(), SwiftDecls.end(),
[&](Decl *LHS, Decl *RHS) -> bool {
auto *LHSValue = dyn_cast<ValueDecl>(LHS);
auto *RHSValue = dyn_cast<ValueDecl>(RHS);
if (LHSValue && RHSValue) {
StringRef LHSName = LHSValue->getName().str();
StringRef RHSName = RHSValue->getName().str();
if (int Ret = LHSName.compare(RHSName))
return Ret < 0;
// FIXME: this is not sufficient to establish a total order for overloaded
// decls.
return LHS->getKind() < RHS->getKind();
}
return LHS->getKind() < RHS->getKind();
});
}
ASTPrinter *PrinterToUse = &Printer;
ClangCommentPrinter RegularCommentPrinter(Printer, Importer);
if (Options.PrintRegularClangComments)
PrinterToUse = &RegularCommentPrinter;
auto PrintDecl = [&](Decl *D) -> bool {
ASTPrinter &Printer = *PrinterToUse;
if (!shouldPrint(D, AdjustedOptions)) {
Printer.callAvoidPrintDeclPost(D);
return false;
}
if (auto Ext = dyn_cast<ExtensionDecl>(D)) {
// Clang extensions (categories) are always printed in source order.
// Swift extensions are printed with their associated type unless it's
// a cross-module extension.
if (!Ext->hasClangNode()) {
auto ExtendedNominal = Ext->getExtendedType()->getAnyNominal();
if (Ext->getModuleContext() == ExtendedNominal->getModuleContext())
return false;
}
}
std::unique_ptr<SynthesizedExtensionAnalyzer> pAnalyzer;
if (auto NTD = dyn_cast<NominalTypeDecl>(D)) {
if (PrintSynthesizedExtensions) {
pAnalyzer.reset(new SynthesizedExtensionAnalyzer(NTD, AdjustedOptions));
AdjustedOptions.shouldCloseNominal = !pAnalyzer->hasMergeGroup(
SynthesizedExtensionAnalyzer::MergeGroupKind::MergableWithTypeDef);
}
}
if (D->print(Printer, AdjustedOptions)) {
if (AdjustedOptions.shouldCloseNominal)
Printer << "\n";
AdjustedOptions.shouldCloseNominal = true;
if (auto NTD = dyn_cast<NominalTypeDecl>(D)) {
std::queue<NominalTypeDecl *> SubDecls{{NTD}};
while (!SubDecls.empty()) {
auto NTD = SubDecls.front();
SubDecls.pop();
// Add sub-types of NTD.
for (auto Sub : NTD->getMembers())
if (auto N = dyn_cast<NominalTypeDecl>(Sub))
SubDecls.push(N);
if (!PrintSynthesizedExtensions) {
// Print Ext and add sub-types of Ext.
for (auto Ext : NTD->getExtensions()) {
if (!shouldPrint(Ext, AdjustedOptions)) {
Printer.callAvoidPrintDeclPost(Ext);
continue;
}
if (Ext->hasClangNode())
continue; // will be printed in its source location, see above.
Printer << "\n";
Ext->print(Printer, AdjustedOptions);
Printer << "\n";
for (auto Sub : Ext->getMembers())
if (auto N = dyn_cast<NominalTypeDecl>(Sub))
SubDecls.push(N);
}
continue;
}
bool IsTopLevelDecl = D == NTD;
// If printed Decl is the top-level, merge the constraint-free extensions
// into the main body.
if (IsTopLevelDecl) {
// Print the part that should be merged with the type decl.
pAnalyzer->forEachExtensionMergeGroup(
SynthesizedExtensionAnalyzer::MergeGroupKind::MergableWithTypeDef,
[&](ArrayRef<ExtensionAndIsSynthesized> Decls){
for (auto ET : Decls) {
AdjustedOptions.shouldOpenExtension = false;
AdjustedOptions.shouldCloseExtension =
Decls.back().first == ET.first;
if (ET.second)
AdjustedOptions.
initArchetypeTransformerForSynthesizedExtensions(NTD,
pAnalyzer.get());
ET.first->print(Printer, AdjustedOptions);
if (ET.second)
AdjustedOptions.
clearArchetypeTransformerForSynthesizedExtensions();
if (AdjustedOptions.shouldCloseExtension)
Printer << "\n";
}
});
}
// If the printed Decl is not the top-level one, reset analyzer.
if (!IsTopLevelDecl)
pAnalyzer.reset(new SynthesizedExtensionAnalyzer(NTD, AdjustedOptions));
// Print the rest as synthesized extensions.
pAnalyzer->forEachExtensionMergeGroup(
// For top-level decls, only contraint extensions are to print;
// Since the rest are merged into the main body.
IsTopLevelDecl ?
SynthesizedExtensionAnalyzer::MergeGroupKind::UnmergableWithTypeDef :
// For sub-decls, all extensions should be printed.
SynthesizedExtensionAnalyzer::MergeGroupKind::All,
[&](ArrayRef<ExtensionAndIsSynthesized> Decls){
for (auto ET : Decls) {
AdjustedOptions.shouldOpenExtension =
Decls.front().first == ET.first;
AdjustedOptions.shouldCloseExtension =
Decls.back().first == ET.first;
if (AdjustedOptions.shouldOpenExtension)
Printer << "\n";
if (ET.second)
AdjustedOptions.
initArchetypeTransformerForSynthesizedExtensions(NTD,
pAnalyzer.get());
ET.first->print(Printer, AdjustedOptions);
if (ET.second)
AdjustedOptions.
clearArchetypeTransformerForSynthesizedExtensions();
if (AdjustedOptions.shouldCloseExtension)
Printer << "\n";
}
});
}
}
return true;
}
return false;
};
// Imports from the stdlib are internal details that don't need to be exposed.
if (!M->isStdlibModule()) {
for (auto *D : ImportDecls)
PrintDecl(D);
Printer << "\n";
}
{
using ModuleAndName = std::pair<const clang::Module *, std::string>;
SmallVector<ModuleAndName, 8> ClangModules;
for (auto P : ClangDecls) {
ClangModules.push_back({ P.first, P.first->getFullModuleName() });
}
// Sort modules by name.
std::sort(ClangModules.begin(), ClangModules.end(),
[](const ModuleAndName &LHS, const ModuleAndName &RHS)
-> bool {
return LHS.second < RHS.second;
});
for (auto CM : ClangModules) {
for (auto DeclAndLoc : ClangDecls[CM.first])
PrintDecl(DeclAndLoc.first);
}
}
if (!(TraversalOptions & ModuleTraversal::SkipOverlay) ||
!InterestingClangModule) {
for (auto *D : SwiftDecls) {
if (PrintDecl(D))
Printer << "\n";
}
}
}
/// Iteratively perform simplification on a worklist of users
/// of the specified induction variable. Each successive simplification may push
/// more users which may themselves be candidates for simplification.
///
/// This algorithm does not require IVUsers analysis. Instead, it simplifies
/// instructions in-place during analysis. Rather than rewriting induction
/// variables bottom-up from their users, it transforms a chain of IVUsers
/// top-down, updating the IR only when it encounters a clear optimization
/// opportunity.
///
/// Once DisableIVRewrite is default, LSR will be the only client of IVUsers.
///
void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
if (!SE->isSCEVable(CurrIV->getType()))
return;
// Instructions processed by SimplifyIndvar for CurrIV.
SmallPtrSet<Instruction*,16> Simplified;
// Use-def pairs if IV users waiting to be processed for CurrIV.
SmallVector<std::pair<Instruction*, Instruction*>, 8> SimpleIVUsers;
// Push users of the current LoopPhi. In rare cases, pushIVUsers may be
// called multiple times for the same LoopPhi. This is the proper thing to
// do for loop header phis that use each other.
pushIVUsers(CurrIV, L, Simplified, SimpleIVUsers);
while (!SimpleIVUsers.empty()) {
std::pair<Instruction*, Instruction*> UseOper =
SimpleIVUsers.pop_back_val();
Instruction *UseInst = UseOper.first;
// Bypass back edges to avoid extra work.
if (UseInst == CurrIV) continue;
// Try to replace UseInst with a loop invariant before any other
// simplifications.
if (replaceIVUserWithLoopInvariant(UseInst))
continue;
Instruction *IVOperand = UseOper.second;
for (unsigned N = 0; IVOperand; ++N) {
assert(N <= Simplified.size() && "runaway iteration");
Value *NewOper = foldIVUser(UseOper.first, IVOperand);
if (!NewOper)
break; // done folding
IVOperand = dyn_cast<Instruction>(NewOper);
}
if (!IVOperand)
continue;
if (eliminateIVUser(UseOper.first, IVOperand)) {
pushIVUsers(IVOperand, L, Simplified, SimpleIVUsers);
continue;
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(UseOper.first)) {
if ((isa<OverflowingBinaryOperator>(BO) &&
strengthenOverflowingOperation(BO, IVOperand)) ||
(isa<ShlOperator>(BO) && strengthenRightShift(BO, IVOperand))) {
// re-queue uses of the now modified binary operator and fall
// through to the checks that remain.
pushIVUsers(IVOperand, L, Simplified, SimpleIVUsers);
}
}
CastInst *Cast = dyn_cast<CastInst>(UseOper.first);
if (V && Cast) {
V->visitCast(Cast);
continue;
}
if (isSimpleIVUser(UseOper.first, L, SE)) {
pushIVUsers(UseOper.first, L, Simplified, SimpleIVUsers);
}
}
}
void llvm::calculateClrEHStateNumbers(const Function *Fn,
WinEHFuncInfo &FuncInfo) {
// Return if it's already been done.
if (!FuncInfo.EHPadStateMap.empty())
return;
// This numbering assigns one state number to each catchpad and cleanuppad.
// It also computes two tree-like relations over states:
// 1) Each state has a "HandlerParentState", which is the state of the next
// outer handler enclosing this state's handler (same as nearest ancestor
// per the ParentPad linkage on EH pads, but skipping over catchswitches).
// 2) Each state has a "TryParentState", which:
// a) for a catchpad that's not the last handler on its catchswitch, is
// the state of the next catchpad on that catchswitch
// b) for all other pads, is the state of the pad whose try region is the
// next outer try region enclosing this state's try region. The "try
// regions are not present as such in the IR, but will be inferred
// based on the placement of invokes and pads which reach each other
// by exceptional exits
// Catchswitches do not get their own states, but each gets mapped to the
// state of its first catchpad.
// Step one: walk down from outermost to innermost funclets, assigning each
// catchpad and cleanuppad a state number. Add an entry to the
// ClrEHUnwindMap for each state, recording its HandlerParentState and
// handler attributes. Record the TryParentState as well for each catchpad
// that's not the last on its catchswitch, but initialize all other entries'
// TryParentStates to a sentinel -1 value that the next pass will update.
// Seed a worklist with pads that have no parent.
SmallVector<std::pair<const Instruction *, int>, 8> Worklist;
for (const BasicBlock &BB : *Fn) {
const Instruction *FirstNonPHI = BB.getFirstNonPHI();
const Value *ParentPad;
if (const auto *CPI = dyn_cast<CleanupPadInst>(FirstNonPHI))
ParentPad = CPI->getParentPad();
else if (const auto *CSI = dyn_cast<CatchSwitchInst>(FirstNonPHI))
ParentPad = CSI->getParentPad();
else
continue;
if (isa<ConstantTokenNone>(ParentPad))
Worklist.emplace_back(FirstNonPHI, -1);
}
// Use the worklist to visit all pads, from outer to inner. Record
// HandlerParentState for all pads. Record TryParentState only for catchpads
// that aren't the last on their catchswitch (setting all other entries'
// TryParentStates to an initial value of -1). This loop is also responsible
// for setting the EHPadStateMap entry for all catchpads, cleanuppads, and
// catchswitches.
while (!Worklist.empty()) {
const Instruction *Pad;
int HandlerParentState;
std::tie(Pad, HandlerParentState) = Worklist.pop_back_val();
if (const auto *Cleanup = dyn_cast<CleanupPadInst>(Pad)) {
// Create the entry for this cleanup with the appropriate handler
// properties. Finally and fault handlers are distinguished by arity.
ClrHandlerType HandlerType =
(Cleanup->getNumArgOperands() ? ClrHandlerType::Fault
: ClrHandlerType::Finally);
int CleanupState = addClrEHHandler(FuncInfo, HandlerParentState, -1,
HandlerType, 0, Pad->getParent());
// Queue any child EH pads on the worklist.
for (const User *U : Cleanup->users())
if (const auto *I = dyn_cast<Instruction>(U))
if (I->isEHPad())
Worklist.emplace_back(I, CleanupState);
// Remember this pad's state.
FuncInfo.EHPadStateMap[Cleanup] = CleanupState;
} else {
// Walk the handlers of this catchswitch in reverse order since all but
// the last need to set the following one as its TryParentState.
const auto *CatchSwitch = cast<CatchSwitchInst>(Pad);
int CatchState = -1, FollowerState = -1;
SmallVector<const BasicBlock *, 4> CatchBlocks(CatchSwitch->handlers());
for (auto CBI = CatchBlocks.rbegin(), CBE = CatchBlocks.rend();
CBI != CBE; ++CBI, FollowerState = CatchState) {
const BasicBlock *CatchBlock = *CBI;
// Create the entry for this catch with the appropriate handler
// properties.
const auto *Catch = cast<CatchPadInst>(CatchBlock->getFirstNonPHI());
uint32_t TypeToken = static_cast<uint32_t>(
cast<ConstantInt>(Catch->getArgOperand(0))->getZExtValue());
CatchState =
addClrEHHandler(FuncInfo, HandlerParentState, FollowerState,
ClrHandlerType::Catch, TypeToken, CatchBlock);
// Queue any child EH pads on the worklist.
for (const User *U : Catch->users())
if (const auto *I = dyn_cast<Instruction>(U))
if (I->isEHPad())
Worklist.emplace_back(I, CatchState);
// Remember this catch's state.
FuncInfo.EHPadStateMap[Catch] = CatchState;
}
// Associate the catchswitch with the state of its first catch.
assert(CatchSwitch->getNumHandlers());
FuncInfo.EHPadStateMap[CatchSwitch] = CatchState;
}
}
// Step two: record the TryParentState of each state. For cleanuppads that
// don't have cleanuprets, we may need to infer this from their child pads,
// so visit pads in descendant-most to ancestor-most order.
for (auto Entry = FuncInfo.ClrEHUnwindMap.rbegin(),
End = FuncInfo.ClrEHUnwindMap.rend();
Entry != End; ++Entry) {
const Instruction *Pad =
Entry->Handler.get<const BasicBlock *>()->getFirstNonPHI();
// For most pads, the TryParentState is the state associated with the
// unwind dest of exceptional exits from it.
const BasicBlock *UnwindDest;
if (const auto *Catch = dyn_cast<CatchPadInst>(Pad)) {
// If a catch is not the last in its catchswitch, its TryParentState is
// the state associated with the next catch in the switch, even though
// that's not the unwind dest of exceptions escaping the catch. Those
// cases were already assigned a TryParentState in the first pass, so
// skip them.
if (Entry->TryParentState != -1)
continue;
// Otherwise, get the unwind dest from the catchswitch.
UnwindDest = Catch->getCatchSwitch()->getUnwindDest();
} else {
const auto *Cleanup = cast<CleanupPadInst>(Pad);
UnwindDest = nullptr;
for (const User *U : Cleanup->users()) {
if (auto *CleanupRet = dyn_cast<CleanupReturnInst>(U)) {
// Common and unambiguous case -- cleanupret indicates cleanup's
// unwind dest.
UnwindDest = CleanupRet->getUnwindDest();
break;
}
// Get an unwind dest for the user
const BasicBlock *UserUnwindDest = nullptr;
if (auto *Invoke = dyn_cast<InvokeInst>(U)) {
UserUnwindDest = Invoke->getUnwindDest();
} else if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(U)) {
UserUnwindDest = CatchSwitch->getUnwindDest();
} else if (auto *ChildCleanup = dyn_cast<CleanupPadInst>(U)) {
int UserState = FuncInfo.EHPadStateMap[ChildCleanup];
int UserUnwindState =
FuncInfo.ClrEHUnwindMap[UserState].TryParentState;
if (UserUnwindState != -1)
UserUnwindDest = FuncInfo.ClrEHUnwindMap[UserUnwindState]
.Handler.get<const BasicBlock *>();
}
// Not having an unwind dest for this user might indicate that it
// doesn't unwind, so can't be taken as proof that the cleanup itself
// may unwind to caller (see e.g. SimplifyUnreachable and
// RemoveUnwindEdge).
if (!UserUnwindDest)
continue;
// Now we have an unwind dest for the user, but we need to see if it
// unwinds all the way out of the cleanup or if it stays within it.
const Instruction *UserUnwindPad = UserUnwindDest->getFirstNonPHI();
const Value *UserUnwindParent;
if (auto *CSI = dyn_cast<CatchSwitchInst>(UserUnwindPad))
UserUnwindParent = CSI->getParentPad();
else
UserUnwindParent =
cast<CleanupPadInst>(UserUnwindPad)->getParentPad();
// The unwind stays within the cleanup iff it targets a child of the
// cleanup.
if (UserUnwindParent == Cleanup)
continue;
// This unwind exits the cleanup, so its dest is the cleanup's dest.
UnwindDest = UserUnwindDest;
break;
}
}
// Record the state of the unwind dest as the TryParentState.
int UnwindDestState;
// If UnwindDest is null at this point, either the pad in question can
// be exited by unwind to caller, or it cannot be exited by unwind. In
// either case, reporting such cases as unwinding to caller is correct.
// This can lead to EH tables that "look strange" -- if this pad's is in
// a parent funclet which has other children that do unwind to an enclosing
// pad, the try region for this pad will be missing the "duplicate" EH
// clause entries that you'd expect to see covering the whole parent. That
// should be benign, since the unwind never actually happens. If it were
// an issue, we could add a subsequent pass that pushes unwind dests down
// from parents that have them to children that appear to unwind to caller.
if (!UnwindDest) {
UnwindDestState = -1;
} else {
UnwindDestState = FuncInfo.EHPadStateMap[UnwindDest->getFirstNonPHI()];
}
Entry->TryParentState = UnwindDestState;
}
// Step three: transfer information from pads to invokes.
calculateStateNumbersForInvokes(Fn, FuncInfo);
}
static unsigned scanFromBlock(const CFGBlock *Start,
llvm::BitVector &Reachable,
Preprocessor *PP,
bool IncludeSometimesUnreachableEdges) {
unsigned count = 0;
// Prep work queue
SmallVector<const CFGBlock*, 32> WL;
// The entry block may have already been marked reachable
// by the caller.
if (!Reachable[Start->getBlockID()]) {
++count;
Reachable[Start->getBlockID()] = true;
}
WL.push_back(Start);
// Find the reachable blocks from 'Start'.
while (!WL.empty()) {
const CFGBlock *item = WL.pop_back_val();
// There are cases where we want to treat all successors as reachable.
// The idea is that some "sometimes unreachable" code is not interesting,
// and that we should forge ahead and explore those branches anyway.
// This allows us to potentially uncover some "always unreachable" code
// within the "sometimes unreachable" code.
// Look at the successors and mark then reachable.
Optional<bool> TreatAllSuccessorsAsReachable;
if (!IncludeSometimesUnreachableEdges)
TreatAllSuccessorsAsReachable = false;
for (CFGBlock::const_succ_iterator I = item->succ_begin(),
E = item->succ_end(); I != E; ++I) {
const CFGBlock *B = *I;
if (!B) do {
const CFGBlock *UB = I->getPossiblyUnreachableBlock();
if (!UB)
break;
if (!TreatAllSuccessorsAsReachable.hasValue()) {
assert(PP);
TreatAllSuccessorsAsReachable =
shouldTreatSuccessorsAsReachable(item, *PP);
}
if (TreatAllSuccessorsAsReachable.getValue()) {
B = UB;
break;
}
}
while (false);
if (B) {
unsigned blockID = B->getBlockID();
if (!Reachable[blockID]) {
Reachable.set(blockID);
WL.push_back(B);
++count;
}
}
}
}
return count;
}
void WinEHPrepare::cloneCommonBlocks(Function &F) {
// We need to clone all blocks which belong to multiple funclets. Values are
// remapped throughout the funclet to propagate both the new instructions
// *and* the new basic blocks themselves.
for (auto &Funclets : FuncletBlocks) {
BasicBlock *FuncletPadBB = Funclets.first;
std::vector<BasicBlock *> &BlocksInFunclet = Funclets.second;
Value *FuncletToken;
if (FuncletPadBB == &F.getEntryBlock())
FuncletToken = ConstantTokenNone::get(F.getContext());
else
FuncletToken = FuncletPadBB->getFirstNonPHI();
std::vector<std::pair<BasicBlock *, BasicBlock *>> Orig2Clone;
ValueToValueMapTy VMap;
for (BasicBlock *BB : BlocksInFunclet) {
ColorVector &ColorsForBB = BlockColors[BB];
// We don't need to do anything if the block is monochromatic.
size_t NumColorsForBB = ColorsForBB.size();
if (NumColorsForBB == 1)
continue;
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Cloning block \'" << BB->getName()
<< "\' for funclet \'" << FuncletPadBB->getName()
<< "\'.\n");
// Create a new basic block and copy instructions into it!
BasicBlock *CBB =
CloneBasicBlock(BB, VMap, Twine(".for.", FuncletPadBB->getName()));
// Insert the clone immediately after the original to ensure determinism
// and to keep the same relative ordering of any funclet's blocks.
CBB->insertInto(&F, BB->getNextNode());
// Add basic block mapping.
VMap[BB] = CBB;
// Record delta operations that we need to perform to our color mappings.
Orig2Clone.emplace_back(BB, CBB);
}
// If nothing was cloned, we're done cloning in this funclet.
if (Orig2Clone.empty())
continue;
// Update our color mappings to reflect that one block has lost a color and
// another has gained a color.
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
BlocksInFunclet.push_back(NewBlock);
ColorVector &NewColors = BlockColors[NewBlock];
assert(NewColors.empty() && "A new block should only have one color!");
NewColors.push_back(FuncletPadBB);
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Assigned color \'" << FuncletPadBB->getName()
<< "\' to block \'" << NewBlock->getName()
<< "\'.\n");
BlocksInFunclet.erase(
std::remove(BlocksInFunclet.begin(), BlocksInFunclet.end(), OldBlock),
BlocksInFunclet.end());
ColorVector &OldColors = BlockColors[OldBlock];
OldColors.erase(
std::remove(OldColors.begin(), OldColors.end(), FuncletPadBB),
OldColors.end());
DEBUG_WITH_TYPE("winehprepare-coloring",
dbgs() << " Removed color \'" << FuncletPadBB->getName()
<< "\' from block \'" << OldBlock->getName()
<< "\'.\n");
}
// Loop over all of the instructions in this funclet, fixing up operand
// references as we go. This uses VMap to do all the hard work.
for (BasicBlock *BB : BlocksInFunclet)
// Loop over all instructions, fixing each one as we find it...
for (Instruction &I : *BB)
RemapInstruction(&I, VMap,
RF_IgnoreMissingLocals | RF_NoModuleLevelChanges);
// Catchrets targeting cloned blocks need to be updated separately from
// the loop above because they are not in the current funclet.
SmallVector<CatchReturnInst *, 2> FixupCatchrets;
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
FixupCatchrets.clear();
for (BasicBlock *Pred : predecessors(OldBlock))
if (auto *CatchRet = dyn_cast<CatchReturnInst>(Pred->getTerminator()))
if (CatchRet->getCatchSwitchParentPad() == FuncletToken)
FixupCatchrets.push_back(CatchRet);
for (CatchReturnInst *CatchRet : FixupCatchrets)
CatchRet->setSuccessor(NewBlock);
}
auto UpdatePHIOnClonedBlock = [&](PHINode *PN, bool IsForOldBlock) {
unsigned NumPreds = PN->getNumIncomingValues();
for (unsigned PredIdx = 0, PredEnd = NumPreds; PredIdx != PredEnd;
++PredIdx) {
BasicBlock *IncomingBlock = PN->getIncomingBlock(PredIdx);
bool EdgeTargetsFunclet;
if (auto *CRI =
dyn_cast<CatchReturnInst>(IncomingBlock->getTerminator())) {
EdgeTargetsFunclet = (CRI->getCatchSwitchParentPad() == FuncletToken);
} else {
ColorVector &IncomingColors = BlockColors[IncomingBlock];
assert(!IncomingColors.empty() && "Block not colored!");
assert((IncomingColors.size() == 1 ||
llvm::all_of(IncomingColors,
[&](BasicBlock *Color) {
return Color != FuncletPadBB;
})) &&
"Cloning should leave this funclet's blocks monochromatic");
EdgeTargetsFunclet = (IncomingColors.front() == FuncletPadBB);
}
if (IsForOldBlock != EdgeTargetsFunclet)
continue;
PN->removeIncomingValue(IncomingBlock, /*DeletePHIIfEmpty=*/false);
// Revisit the next entry.
--PredIdx;
--PredEnd;
}
};
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
for (PHINode &OldPN : OldBlock->phis()) {
UpdatePHIOnClonedBlock(&OldPN, /*IsForOldBlock=*/true);
}
for (PHINode &NewPN : NewBlock->phis()) {
UpdatePHIOnClonedBlock(&NewPN, /*IsForOldBlock=*/false);
}
}
// Check to see if SuccBB has PHI nodes. If so, we need to add entries to
// the PHI nodes for NewBB now.
for (auto &BBMapping : Orig2Clone) {
BasicBlock *OldBlock = BBMapping.first;
BasicBlock *NewBlock = BBMapping.second;
for (BasicBlock *SuccBB : successors(NewBlock)) {
for (PHINode &SuccPN : SuccBB->phis()) {
// Ok, we have a PHI node. Figure out what the incoming value was for
// the OldBlock.
int OldBlockIdx = SuccPN.getBasicBlockIndex(OldBlock);
if (OldBlockIdx == -1)
break;
Value *IV = SuccPN.getIncomingValue(OldBlockIdx);
// Remap the value if necessary.
if (auto *Inst = dyn_cast<Instruction>(IV)) {
ValueToValueMapTy::iterator I = VMap.find(Inst);
if (I != VMap.end())
IV = I->second;
}
SuccPN.addIncoming(IV, NewBlock);
}
}
}
for (ValueToValueMapTy::value_type VT : VMap) {
// If there were values defined in BB that are used outside the funclet,
// then we now have to update all uses of the value to use either the
// original value, the cloned value, or some PHI derived value. This can
// require arbitrary PHI insertion, of which we are prepared to do, clean
// these up now.
SmallVector<Use *, 16> UsesToRename;
auto *OldI = dyn_cast<Instruction>(const_cast<Value *>(VT.first));
if (!OldI)
continue;
auto *NewI = cast<Instruction>(VT.second);
// Scan all uses of this instruction to see if it is used outside of its
// funclet, and if so, record them in UsesToRename.
for (Use &U : OldI->uses()) {
Instruction *UserI = cast<Instruction>(U.getUser());
BasicBlock *UserBB = UserI->getParent();
ColorVector &ColorsForUserBB = BlockColors[UserBB];
assert(!ColorsForUserBB.empty());
if (ColorsForUserBB.size() > 1 ||
*ColorsForUserBB.begin() != FuncletPadBB)
UsesToRename.push_back(&U);
}
// If there are no uses outside the block, we're done with this
// instruction.
if (UsesToRename.empty())
continue;
// We found a use of OldI outside of the funclet. Rename all uses of OldI
// that are outside its funclet to be uses of the appropriate PHI node
// etc.
SSAUpdater SSAUpdate;
SSAUpdate.Initialize(OldI->getType(), OldI->getName());
SSAUpdate.AddAvailableValue(OldI->getParent(), OldI);
SSAUpdate.AddAvailableValue(NewI->getParent(), NewI);
while (!UsesToRename.empty())
SSAUpdate.RewriteUseAfterInsertions(*UsesToRename.pop_back_val());
}
}
}
RequirementCheckResult TypeChecker::checkGenericArguments(
DeclContext *dc, SourceLoc loc, SourceLoc noteLoc, Type owner,
GenericSignature *genericSig, TypeSubstitutionFn substitutions,
LookupConformanceFn conformances,
UnsatisfiedDependency *unsatisfiedDependency,
ConformanceCheckOptions conformanceOptions,
GenericRequirementsCheckListener *listener,
SubstOptions options) {
bool valid = true;
struct RequirementSet {
ArrayRef<Requirement> Requirements;
SmallVector<ParentConditionalConformance, 4> Parents;
};
SmallVector<RequirementSet, 8> pendingReqs;
pendingReqs.push_back({genericSig->getRequirements(), {}});
while (!pendingReqs.empty()) {
auto current = pendingReqs.pop_back_val();
for (const auto &rawReq : current.Requirements) {
auto req = rawReq;
if (current.Parents.empty()) {
auto substed = rawReq.subst(substitutions, conformances, options);
if (!substed) {
// Another requirement will fail later; just continue.
valid = false;
continue;
}
req = *substed;
}
auto kind = req.getKind();
Type rawFirstType = rawReq.getFirstType();
Type firstType = req.getFirstType();
Type rawSecondType, secondType;
if (kind != RequirementKind::Layout) {
rawSecondType = rawReq.getSecondType();
secondType = req.getSecondType();
}
bool requirementFailure = false;
if (listener && !listener->shouldCheck(kind, firstType, secondType))
continue;
Diag<Type, Type, Type> diagnostic;
Diag<Type, Type, StringRef> diagnosticNote;
switch (kind) {
case RequirementKind::Conformance: {
// Protocol conformance requirements.
auto proto = secondType->castTo<ProtocolType>();
// FIXME: This should track whether this should result in a private
// or non-private dependency.
// FIXME: Do we really need "used" at this point?
// FIXME: Poor location information. How much better can we do here?
// FIXME: This call should support listener to be able to properly
// diagnose problems with conformances.
auto result =
conformsToProtocol(firstType, proto->getDecl(), dc,
conformanceOptions, loc, unsatisfiedDependency);
// Unsatisfied dependency case.
auto status = result.getStatus();
switch (status) {
case RequirementCheckResult::Failure:
// A failure at the top level is diagnosed elsewhere.
if (current.Parents.empty())
return status;
diagnostic = diag::type_does_not_conform_owner;
diagnosticNote = diag::type_does_not_inherit_or_conform_requirement;
requirementFailure = true;
break;
case RequirementCheckResult::UnsatisfiedDependency:
case RequirementCheckResult::SubstitutionFailure:
// pass it on up.
return status;
case RequirementCheckResult::Success: {
auto conformance = result.getConformance();
// Report the conformance.
if (listener && valid && current.Parents.empty()) {
listener->satisfiedConformance(rawFirstType, firstType,
conformance);
}
auto conditionalReqs = conformance.getConditionalRequirements();
if (!conditionalReqs.empty()) {
auto history = current.Parents;
history.push_back({firstType, proto});
pendingReqs.push_back({conditionalReqs, std::move(history)});
}
continue;
}
}
// Failure needs to emit a diagnostic.
break;
}
case RequirementKind::Layout: {
// TODO: Statically check if a the first type
// conforms to the layout constraint, once we
// support such static checks.
continue;
}
case RequirementKind::Superclass:
// Superclass requirements.
if (!isSubclassOf(firstType, secondType, dc)) {
diagnostic = diag::type_does_not_inherit;
diagnosticNote = diag::type_does_not_inherit_or_conform_requirement;
requirementFailure = true;
}
break;
case RequirementKind::SameType:
if (!firstType->isEqual(secondType)) {
diagnostic = diag::types_not_equal;
diagnosticNote = diag::types_not_equal_requirement;
requirementFailure = true;
}
break;
}
if (!requirementFailure)
continue;
if (listener &&
listener->diagnoseUnsatisfiedRequirement(rawReq, firstType,
secondType, current.Parents))
return RequirementCheckResult::Failure;
if (loc.isValid()) {
// FIXME: Poor source-location information.
diagnose(loc, diagnostic, owner, firstType, secondType);
diagnose(noteLoc, diagnosticNote, rawFirstType, rawSecondType,
genericSig->gatherGenericParamBindingsText(
{rawFirstType, rawSecondType}, substitutions));
ParentConditionalConformance::diagnoseConformanceStack(Diags, noteLoc,
current.Parents);
}
return RequirementCheckResult::Failure;
}
}
if (valid)
return RequirementCheckResult::Success;
return RequirementCheckResult::SubstitutionFailure;
}
bool WebAssemblyRegStackify::runOnMachineFunction(MachineFunction &MF) {
DEBUG(dbgs() << "********** Register Stackifying **********\n"
"********** Function: "
<< MF.getName() << '\n');
bool Changed = false;
MachineRegisterInfo &MRI = MF.getRegInfo();
WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
const auto *TRI = MF.getSubtarget<WebAssemblySubtarget>().getRegisterInfo();
AliasAnalysis &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
LiveIntervals &LIS = getAnalysis<LiveIntervals>();
// Walk the instructions from the bottom up. Currently we don't look past
// block boundaries, and the blocks aren't ordered so the block visitation
// order isn't significant, but we may want to change this in the future.
for (MachineBasicBlock &MBB : MF) {
// Don't use a range-based for loop, because we modify the list as we're
// iterating over it and the end iterator may change.
for (auto MII = MBB.rbegin(); MII != MBB.rend(); ++MII) {
MachineInstr *Insert = &*MII;
// Don't nest anything inside a phi.
if (Insert->getOpcode() == TargetOpcode::PHI)
break;
// Don't nest anything inside an inline asm, because we don't have
// constraints for $push inputs.
if (Insert->getOpcode() == TargetOpcode::INLINEASM)
break;
// Iterate through the inputs in reverse order, since we'll be pulling
// operands off the stack in LIFO order.
bool AnyStackified = false;
for (MachineOperand &Op : reverse(Insert->uses())) {
// We're only interested in explicit virtual register operands.
if (!Op.isReg() || Op.isImplicit() || !Op.isUse())
continue;
unsigned Reg = Op.getReg();
// Only consider registers with a single definition.
// TODO: Eventually we may relax this, to stackify phi transfers.
MachineInstr *Def = MRI.getUniqueVRegDef(Reg);
if (!Def)
continue;
// Don't nest an INLINE_ASM def into anything, because we don't have
// constraints for $pop outputs.
if (Def->getOpcode() == TargetOpcode::INLINEASM)
continue;
// Don't nest PHIs inside of anything.
if (Def->getOpcode() == TargetOpcode::PHI)
continue;
// Argument instructions represent live-in registers and not real
// instructions.
if (Def->getOpcode() == WebAssembly::ARGUMENT_I32 ||
Def->getOpcode() == WebAssembly::ARGUMENT_I64 ||
Def->getOpcode() == WebAssembly::ARGUMENT_F32 ||
Def->getOpcode() == WebAssembly::ARGUMENT_F64)
continue;
if (MRI.hasOneUse(Reg) && Def->getParent() == &MBB &&
IsSafeToMove(Def, Insert, AA, LIS, MRI)) {
// A single-use def in the same block with no intervening memory or
// register dependencies; move the def down and nest it with the
// current instruction.
// TODO: Stackify multiple-use values, taking advantage of set_local
// returning its result.
Changed = true;
AnyStackified = true;
MBB.splice(Insert, &MBB, Def);
LIS.handleMove(Def);
MFI.stackifyVReg(Reg);
ImposeStackOrdering(Def);
Insert = Def;
} else if (Def->isAsCheapAsAMove() &&
TII->isTriviallyReMaterializable(Def, &AA)) {
// A trivially cloneable instruction; clone it and nest the new copy
// with the current instruction.
Changed = true;
AnyStackified = true;
unsigned OldReg = Def->getOperand(0).getReg();
unsigned NewReg = MRI.createVirtualRegister(MRI.getRegClass(OldReg));
TII->reMaterialize(MBB, Insert, NewReg, 0, Def, *TRI);
Op.setReg(NewReg);
MachineInstr *Clone =
&*std::prev(MachineBasicBlock::instr_iterator(Insert));
LIS.InsertMachineInstrInMaps(Clone);
LIS.createAndComputeVirtRegInterval(NewReg);
MFI.stackifyVReg(NewReg);
ImposeStackOrdering(Clone);
Insert = Clone;
// If that was the last use of the original, delete the original.
// Otherwise shrink the LiveInterval.
if (MRI.use_empty(OldReg)) {
SlotIndex Idx = LIS.getInstructionIndex(Def).getRegSlot();
LIS.removePhysRegDefAt(WebAssembly::ARGUMENTS, Idx);
LIS.removeVRegDefAt(LIS.getInterval(OldReg), Idx);
LIS.removeInterval(OldReg);
LIS.RemoveMachineInstrFromMaps(Def);
Def->eraseFromParent();
} else {
LIS.shrinkToUses(&LIS.getInterval(OldReg));
}
}
}
if (AnyStackified)
ImposeStackOrdering(&*MII);
}
}
// If we used EXPR_STACK anywhere, add it to the live-in sets everywhere
// so that it never looks like a use-before-def.
if (Changed) {
MF.getRegInfo().addLiveIn(WebAssembly::EXPR_STACK);
for (MachineBasicBlock &MBB : MF)
MBB.addLiveIn(WebAssembly::EXPR_STACK);
}
#ifndef NDEBUG
// Verify that pushes and pops are performed in LIFO order.
SmallVector<unsigned, 0> Stack;
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
for (MachineOperand &MO : reverse(MI.explicit_operands())) {
if (!MO.isReg())
continue;
unsigned VReg = MO.getReg();
// Don't stackify physregs like SP or FP.
if (!TargetRegisterInfo::isVirtualRegister(VReg))
continue;
if (MFI.isVRegStackified(VReg)) {
if (MO.isDef())
Stack.push_back(VReg);
else
assert(Stack.pop_back_val() == VReg);
}
}
}
// TODO: Generalize this code to support keeping values on the stack across
// basic block boundaries.
assert(Stack.empty());
}
#endif
return Changed;
}
void StackAllocationPromoter::promoteAllocationToPhi() {
DEBUG(llvm::dbgs() << "*** Placing Phis for : " << *ASI);
// A list of blocks that will require new Phi values.
BlockSet PhiBlocks;
// The "piggy-bank" data-structure that we use for processing the dom-tree
// bottom-up.
NodePriorityQueue PQ;
// Collect all of the stores into the AllocStack. We know that at this point
// we have at most one store per block.
for (auto UI = ASI->use_begin(), E = ASI->use_end(); UI != E; ++UI) {
SILInstruction *II = UI->getUser();
// We need to place Phis for this block.
if (isa<StoreInst>(II)) {
// If the block is in the dom tree (dominated by the entry block).
if (DomTreeNode *Node = DT->getNode(II->getParent()))
PQ.push(std::make_pair(Node, DomTreeLevels[Node]));
}
}
DEBUG(llvm::dbgs() << "*** Found: " << PQ.size() << " Defs\n");
// A list of nodes for which we already calculated the dominator frontier.
llvm::SmallPtrSet<DomTreeNode *, 32> Visited;
SmallVector<DomTreeNode *, 32> Worklist;
// Scan all of the definitions in the function bottom-up using the priority
// queue.
while (!PQ.empty()) {
DomTreeNodePair RootPair = PQ.top();
PQ.pop();
DomTreeNode *Root = RootPair.first;
unsigned RootLevel = RootPair.second;
// Walk all dom tree children of Root, inspecting their successors. Only
// J-edges, whose target level is at most Root's level are added to the
// dominance frontier.
Worklist.clear();
Worklist.push_back(Root);
while (!Worklist.empty()) {
DomTreeNode *Node = Worklist.pop_back_val();
SILBasicBlock *BB = Node->getBlock();
// For all successors of the node:
for (auto &Succ : BB->getSuccessors()) {
DomTreeNode *SuccNode = DT->getNode(Succ);
// Skip D-edges (edges that are dom-tree edges).
if (SuccNode->getIDom() == Node)
continue;
// Ignore J-edges that point to nodes that are not smaller or equal
// to the root level.
unsigned SuccLevel = DomTreeLevels[SuccNode];
if (SuccLevel > RootLevel)
continue;
// Ignore visited nodes.
if (!Visited.insert(SuccNode).second)
continue;
// If the new PHInode is not dominated by the allocation then it's dead.
if (!DT->dominates(ASI->getParent(), SuccNode->getBlock()))
continue;
// If the new PHInode is properly dominated by the deallocation then it
// is obviously a dead PHInode, so we don't need to insert it.
if (DSI && DT->properlyDominates(DSI->getParent(),
SuccNode->getBlock()))
continue;
// The successor node is a new PHINode. If this is a new PHI node
// then it may require additional definitions, so add it to the PQ.
if (PhiBlocks.insert(Succ).second)
PQ.push(std::make_pair(SuccNode, SuccLevel));
}
// Add the children in the dom-tree to the worklist.
for (auto CI = Node->begin(), CE = Node->end(); CI != CE; ++CI)
if (!Visited.count(*CI))
Worklist.push_back(*CI);
}
}
DEBUG(llvm::dbgs() << "*** Found: " << PhiBlocks.size() << " new PHIs\n");
NumPhiPlaced += PhiBlocks.size();
// At this point we calculated the locations of all of the new Phi values.
// Next, add the Phi values and promote all of the loads and stores into the
// new locations.
// Replace the dummy values with new block arguments.
addBlockArguments(PhiBlocks);
// Hook up the Phi nodes, loads, and debug_value_addr with incoming values.
fixBranchesAndUses(PhiBlocks);
DEBUG(llvm::dbgs() << "*** Finished placing Phis ***\n");
}
void PathDiagnosticConsumer::HandlePathDiagnostic(
std::unique_ptr<PathDiagnostic> D) {
if (!D || D->path.empty())
return;
// We need to flatten the locations (convert Stmt* to locations) because
// the referenced statements may be freed by the time the diagnostics
// are emitted.
D->flattenLocations();
// If the PathDiagnosticConsumer does not support diagnostics that
// cross file boundaries, prune out such diagnostics now.
if (!supportsCrossFileDiagnostics()) {
// Verify that the entire path is from the same FileID.
FileID FID;
const SourceManager &SMgr = D->path.front()->getLocation().getManager();
SmallVector<const PathPieces *, 5> WorkList;
WorkList.push_back(&D->path);
SmallString<128> buf;
llvm::raw_svector_ostream warning(buf);
warning << "warning: Path diagnostic report is not generated. Current "
<< "output format does not support diagnostics that cross file "
<< "boundaries. Refer to --analyzer-output for valid output "
<< "formats\n";
while (!WorkList.empty()) {
const PathPieces &path = *WorkList.pop_back_val();
for (const auto &I : path) {
const PathDiagnosticPiece *piece = I.get();
FullSourceLoc L = piece->getLocation().asLocation().getExpansionLoc();
if (FID.isInvalid()) {
FID = SMgr.getFileID(L);
} else if (SMgr.getFileID(L) != FID) {
llvm::errs() << warning.str();
return;
}
// Check the source ranges.
ArrayRef<SourceRange> Ranges = piece->getRanges();
for (const auto &I : Ranges) {
SourceLocation L = SMgr.getExpansionLoc(I.getBegin());
if (!L.isFileID() || SMgr.getFileID(L) != FID) {
llvm::errs() << warning.str();
return;
}
L = SMgr.getExpansionLoc(I.getEnd());
if (!L.isFileID() || SMgr.getFileID(L) != FID) {
llvm::errs() << warning.str();
return;
}
}
if (const auto *call = dyn_cast<PathDiagnosticCallPiece>(piece))
WorkList.push_back(&call->path);
else if (const auto *macro = dyn_cast<PathDiagnosticMacroPiece>(piece))
WorkList.push_back(¯o->subPieces);
}
}
if (FID.isInvalid())
return; // FIXME: Emit a warning?
}
// Profile the node to see if we already have something matching it
llvm::FoldingSetNodeID profile;
D->Profile(profile);
void *InsertPos = nullptr;
if (PathDiagnostic *orig = Diags.FindNodeOrInsertPos(profile, InsertPos)) {
// Keep the PathDiagnostic with the shorter path.
// Note, the enclosing routine is called in deterministic order, so the
// results will be consistent between runs (no reason to break ties if the
// size is the same).
const unsigned orig_size = orig->full_size();
const unsigned new_size = D->full_size();
if (orig_size <= new_size)
return;
assert(orig != D.get());
Diags.RemoveNode(orig);
delete orig;
}
Diags.InsertNode(D.release());
}
void ScheduleDAGSDNodes::BuildSchedUnits() {
// During scheduling, the NodeId field of SDNode is used to map SDNodes
// to their associated SUnits by holding SUnits table indices. A value
// of -1 means the SDNode does not yet have an associated SUnit.
unsigned NumNodes = 0;
for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
E = DAG->allnodes_end(); NI != E; ++NI) {
NI->setNodeId(-1);
++NumNodes;
}
// Reserve entries in the vector for each of the SUnits we are creating. This
// ensure that reallocation of the vector won't happen, so SUnit*'s won't get
// invalidated.
// FIXME: Multiply by 2 because we may clone nodes during scheduling.
// This is a temporary workaround.
SUnits.reserve(NumNodes * 2);
// Add all nodes in depth first order.
SmallVector<SDNode*, 64> Worklist;
SmallPtrSet<SDNode*, 64> Visited;
Worklist.push_back(DAG->getRoot().getNode());
Visited.insert(DAG->getRoot().getNode());
SmallVector<SUnit*, 8> CallSUnits;
while (!Worklist.empty()) {
SDNode *NI = Worklist.pop_back_val();
// Add all operands to the worklist unless they've already been added.
for (unsigned i = 0, e = NI->getNumOperands(); i != e; ++i)
if (Visited.insert(NI->getOperand(i).getNode()))
Worklist.push_back(NI->getOperand(i).getNode());
if (isPassiveNode(NI)) // Leaf node, e.g. a TargetImmediate.
continue;
// If this node has already been processed, stop now.
if (NI->getNodeId() != -1) continue;
SUnit *NodeSUnit = newSUnit(NI);
// See if anything is glued to this node, if so, add them to glued
// nodes. Nodes can have at most one glue input and one glue output. Glue
// is required to be the last operand and result of a node.
// Scan up to find glued preds.
SDNode *N = NI;
while (N->getNumOperands() &&
N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue) {
N = N->getOperand(N->getNumOperands()-1).getNode();
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NodeSUnit->NodeNum);
if (N->isMachineOpcode() && TII->get(N->getMachineOpcode()).isCall())
NodeSUnit->isCall = true;
}
// Scan down to find any glued succs.
N = NI;
while (N->getValueType(N->getNumValues()-1) == MVT::Glue) {
SDValue GlueVal(N, N->getNumValues()-1);
// There are either zero or one users of the Glue result.
bool HasGlueUse = false;
for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
UI != E; ++UI)
if (GlueVal.isOperandOf(*UI)) {
HasGlueUse = true;
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NodeSUnit->NodeNum);
N = *UI;
if (N->isMachineOpcode() && TII->get(N->getMachineOpcode()).isCall())
NodeSUnit->isCall = true;
break;
}
if (!HasGlueUse) break;
}
if (NodeSUnit->isCall)
CallSUnits.push_back(NodeSUnit);
// Schedule zero-latency TokenFactor below any nodes that may increase the
// schedule height. Otherwise, ancestors of the TokenFactor may appear to
// have false stalls.
if (NI->getOpcode() == ISD::TokenFactor)
NodeSUnit->isScheduleLow = true;
// If there are glue operands involved, N is now the bottom-most node
// of the sequence of nodes that are glued together.
// Update the SUnit.
NodeSUnit->setNode(N);
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NodeSUnit->NodeNum);
// Compute NumRegDefsLeft. This must be done before AddSchedEdges.
InitNumRegDefsLeft(NodeSUnit);
// Assign the Latency field of NodeSUnit using target-provided information.
computeLatency(NodeSUnit);
}
// Find all call operands.
while (!CallSUnits.empty()) {
SUnit *SU = CallSUnits.pop_back_val();
for (const SDNode *SUNode = SU->getNode(); SUNode;
SUNode = SUNode->getGluedNode()) {
if (SUNode->getOpcode() != ISD::CopyToReg)
continue;
SDNode *SrcN = SUNode->getOperand(2).getNode();
if (isPassiveNode(SrcN)) continue; // Not scheduled.
SUnit *SrcSU = &SUnits[SrcN->getNodeId()];
SrcSU->isCallOp = true;
}
}
}
/// traceSiblingValue - Trace a value that is about to be spilled back to the
/// real defining instructions by looking through sibling copies. Always stay
/// within the range of OrigVNI so the registers are known to carry the same
/// value.
///
/// Determine if the value is defined by all reloads, so spilling isn't
/// necessary - the value is already in the stack slot.
///
/// Return a defining instruction that may be a candidate for rematerialization.
///
MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI,
VNInfo *OrigVNI) {
// Check if a cached value already exists.
SibValueMap::iterator SVI;
bool Inserted;
tie(SVI, Inserted) =
SibValues.insert(std::make_pair(UseVNI, SibValueInfo(UseReg, UseVNI)));
if (!Inserted) {
DEBUG(dbgs() << "Cached value " << PrintReg(UseReg) << ':'
<< UseVNI->id << '@' << UseVNI->def << ' ' << SVI->second);
return SVI->second.DefMI;
}
DEBUG(dbgs() << "Tracing value " << PrintReg(UseReg) << ':'
<< UseVNI->id << '@' << UseVNI->def << '\n');
// List of (Reg, VNI) that have been inserted into SibValues, but need to be
// processed.
SmallVector<std::pair<unsigned, VNInfo*>, 8> WorkList;
WorkList.push_back(std::make_pair(UseReg, UseVNI));
do {
unsigned Reg;
VNInfo *VNI;
tie(Reg, VNI) = WorkList.pop_back_val();
DEBUG(dbgs() << " " << PrintReg(Reg) << ':' << VNI->id << '@' << VNI->def
<< ":\t");
// First check if this value has already been computed.
SVI = SibValues.find(VNI);
assert(SVI != SibValues.end() && "Missing SibValues entry");
// Trace through PHI-defs created by live range splitting.
if (VNI->isPHIDef()) {
// Stop at original PHIs. We don't know the value at the predecessors.
if (VNI->def == OrigVNI->def) {
DEBUG(dbgs() << "orig phi value\n");
SVI->second.DefByOrigPHI = true;
SVI->second.AllDefsAreReloads = false;
propagateSiblingValue(SVI);
continue;
}
// This is a PHI inserted by live range splitting. We could trace the
// live-out value from predecessor blocks, but that search can be very
// expensive if there are many predecessors and many more PHIs as
// generated by tail-dup when it sees an indirectbr. Instead, look at
// all the non-PHI defs that have the same value as OrigVNI. They must
// jointly dominate VNI->def. This is not optimal since VNI may actually
// be jointly dominated by a smaller subset of defs, so there is a change
// we will miss a AllDefsAreReloads optimization.
// Separate all values dominated by OrigVNI into PHIs and non-PHIs.
SmallVector<VNInfo*, 8> PHIs, NonPHIs;
LiveInterval &LI = LIS.getInterval(Reg);
LiveInterval &OrigLI = LIS.getInterval(Original);
for (LiveInterval::vni_iterator VI = LI.vni_begin(), VE = LI.vni_end();
VI != VE; ++VI) {
VNInfo *VNI2 = *VI;
if (VNI2->isUnused())
continue;
if (!OrigLI.containsOneValue() &&
OrigLI.getVNInfoAt(VNI2->def) != OrigVNI)
continue;
if (VNI2->isPHIDef() && VNI2->def != OrigVNI->def)
PHIs.push_back(VNI2);
else
NonPHIs.push_back(VNI2);
}
DEBUG(dbgs() << "split phi value, checking " << PHIs.size()
<< " phi-defs, and " << NonPHIs.size()
<< " non-phi/orig defs\n");
// Create entries for all the PHIs. Don't add them to the worklist, we
// are processing all of them in one go here.
for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
SibValues.insert(std::make_pair(PHIs[i], SibValueInfo(Reg, PHIs[i])));
// Add every PHI as a dependent of all the non-PHIs.
for (unsigned i = 0, e = NonPHIs.size(); i != e; ++i) {
VNInfo *NonPHI = NonPHIs[i];
// Known value? Try an insertion.
tie(SVI, Inserted) =
SibValues.insert(std::make_pair(NonPHI, SibValueInfo(Reg, NonPHI)));
// Add all the PHIs as dependents of NonPHI.
for (unsigned pi = 0, pe = PHIs.size(); pi != pe; ++pi)
SVI->second.Deps.push_back(PHIs[pi]);
// This is the first time we see NonPHI, add it to the worklist.
if (Inserted)
WorkList.push_back(std::make_pair(Reg, NonPHI));
else
// Propagate to all inserted PHIs, not just VNI.
propagateSiblingValue(SVI);
}
// Next work list item.
continue;
}
MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
assert(MI && "Missing def");
// Trace through sibling copies.
if (unsigned SrcReg = isFullCopyOf(MI, Reg)) {
if (isSibling(SrcReg)) {
LiveInterval &SrcLI = LIS.getInterval(SrcReg);
LiveRangeQuery SrcQ(SrcLI, VNI->def);
assert(SrcQ.valueIn() && "Copy from non-existing value");
// Check if this COPY kills its source.
SVI->second.KillsSource = SrcQ.isKill();
VNInfo *SrcVNI = SrcQ.valueIn();
DEBUG(dbgs() << "copy of " << PrintReg(SrcReg) << ':'
<< SrcVNI->id << '@' << SrcVNI->def
<< " kill=" << unsigned(SVI->second.KillsSource) << '\n');
// Known sibling source value? Try an insertion.
tie(SVI, Inserted) = SibValues.insert(std::make_pair(SrcVNI,
SibValueInfo(SrcReg, SrcVNI)));
// This is the first time we see Src, add it to the worklist.
if (Inserted)
WorkList.push_back(std::make_pair(SrcReg, SrcVNI));
propagateSiblingValue(SVI, VNI);
// Next work list item.
continue;
}
}
// Track reachable reloads.
SVI->second.DefMI = MI;
SVI->second.SpillMBB = MI->getParent();
int FI;
if (Reg == TII.isLoadFromStackSlot(MI, FI) && FI == StackSlot) {
DEBUG(dbgs() << "reload\n");
propagateSiblingValue(SVI);
// Next work list item.
continue;
}
// Potential remat candidate.
DEBUG(dbgs() << "def " << *MI);
SVI->second.AllDefsAreReloads = false;
propagateSiblingValue(SVI);
} while (!WorkList.empty());
// Look up the value we were looking for. We already did this lookup at the
// top of the function, but SibValues may have been invalidated.
SVI = SibValues.find(UseVNI);
assert(SVI != SibValues.end() && "Didn't compute requested info");
DEBUG(dbgs() << " traced to:\t" << SVI->second);
return SVI->second.DefMI;
}
bool SILValueOwnershipChecker::gatherUsers(
SmallVectorImpl<BranchPropagatedUser> &lifetimeEndingUsers,
SmallVectorImpl<BranchPropagatedUser> &nonLifetimeEndingUsers,
SmallVectorImpl<BranchPropagatedUser> &implicitRegularUsers) {
// See if Value is guaranteed. If we are guaranteed and not forwarding, then
// we need to look through subobject uses for more uses. Otherwise, if we are
// forwarding, we do not create any lifetime ending users/non lifetime ending
// users since we verify against our base.
auto ownershipKind = value.getOwnershipKind();
bool isGuaranteed = ownershipKind == ValueOwnershipKind::Guaranteed;
bool isOwned = ownershipKind == ValueOwnershipKind::Owned;
if (isGuaranteed && isGuaranteedForwardingValue(value))
return true;
// Then gather up our initial list of users.
SmallVector<Operand *, 8> users;
std::copy(value->use_begin(), value->use_end(), std::back_inserter(users));
auto addCondBranchToList = [](SmallVectorImpl<BranchPropagatedUser> &list,
CondBranchInst *cbi, unsigned operandIndex) {
if (cbi->isConditionOperandIndex(operandIndex)) {
list.emplace_back(cbi);
return;
}
bool isTrueOperand = cbi->isTrueOperandIndex(operandIndex);
list.emplace_back(cbi, isTrueOperand ? CondBranchInst::TrueIdx
: CondBranchInst::FalseIdx);
};
bool foundError = false;
while (!users.empty()) {
Operand *op = users.pop_back_val();
SILInstruction *user = op->getUser();
// If this op is a type dependent operand, skip it. It is not interesting
// from an ownership perspective.
if (user->isTypeDependentOperand(*op))
continue;
bool isGuaranteedSubValue = false;
if (isGuaranteed && isGuaranteedForwardingInst(op->getUser())) {
isGuaranteedSubValue = true;
}
auto opOwnershipKindMap = op->getOwnershipKindMap(isGuaranteedSubValue);
// If our ownership kind doesn't match, track that we found an error, emit
// an error message optionally and then continue.
if (!opOwnershipKindMap.canAcceptKind(ownershipKind)) {
foundError = true;
// If we did not support /any/ ownership kind, it means that we found a
// conflicting answer so the kind map that was returned is the empty
// map. Put out a more specific error here.
if (!opOwnershipKindMap.data.any()) {
handleError([&]() {
llvm::errs() << "Function: '" << user->getFunction()->getName()
<< "'\n"
<< "Ill-formed SIL! Unable to compute ownership kind "
"map for user?!\n"
<< "For terminator users, check that successors have "
"compatible ownership kinds.\n"
<< "Value: " << op->get() << "User: "******"Operand Number: " << op->getOperandNumber() << '\n'
<< "Conv: " << ownershipKind << "\n\n";
});
continue;
}
handleError([&]() {
llvm::errs() << "Function: '" << user->getFunction()->getName() << "'\n"
<< "Have operand with incompatible ownership?!\n"
<< "Value: " << op->get() << "User: "******"Operand Number: " << op->getOperandNumber() << '\n'
<< "Conv: " << ownershipKind << '\n'
<< "OwnershipMap:\n"
<< opOwnershipKindMap << '\n';
});
continue;
}
auto lifetimeConstraint =
opOwnershipKindMap.getLifetimeConstraint(ownershipKind);
if (lifetimeConstraint == UseLifetimeConstraint::MustBeInvalidated) {
LLVM_DEBUG(llvm::dbgs() << " Lifetime Ending User: "******" Regular User: "******"Our value is guaranteed and this is a forwarding instruction. "
"Should have guaranteed ownership as well.");
copy(result->getUses(), std::back_inserter(users));
}
continue;
}
assert(user->getResults().empty());
auto *ti = dyn_cast<TermInst>(user);
if (!ti) {
continue;
}
// Otherwise if we have a terminator, add any as uses any end_borrow to
// ensure that the subscope is completely enclsed within the super scope. We
// require all of our arguments to be either trivial or guaranteed.
for (auto &succ : ti->getSuccessors()) {
auto *succBlock = succ.getBB();
// If we do not have any arguments, then continue.
if (succBlock->args_empty())
continue;
// Otherwise, make sure that all arguments are trivial or guaranteed. If
// we fail, emit an error.
//
// TODO: We could ignore this error and emit a more specific error on the
// actual terminator.
for (auto *succArg : succBlock->getPhiArguments()) {
// *NOTE* We do not emit an error here since we want to allow for more
// specific errors to be found during use_verification.
//
// TODO: Add a flag that associates the terminator instruction with
// needing to be verified. If it isn't verified appropriately, assert
// when the verifier is destroyed.
auto succArgOwnershipKind = succArg->getOwnershipKind();
if (!succArgOwnershipKind.isTrivialOrCompatibleWith(ownershipKind)) {
// This is where the error would go.
continue;
}
// If we have a trivial value, just continue.
if (succArgOwnershipKind == ValueOwnershipKind::Trivial)
continue;
// Otherwise add all end_borrow users for this BBArg to the
// implicit regular user list. We know that BBArg must be
// completely joint post-dominated by these users, so we use
// them to ensure that all of BBArg's uses are completely
// enclosed within the end_borrow of this argument.
for (auto *op : succArg->getUses()) {
if (auto *ebi = dyn_cast<EndBorrowInst>(op->getUser())) {
implicitRegularUsers.push_back(ebi);
}
}
}
}
}
// Return true if we did not have an error and false if we did find an error.
//
// The reason why we use this extra variable is to make sure that when we are
// testing, we print out all mismatching pairs rather than just the first.
return !foundError;
}
void IndVarSimplify::RewriteIVExpressions(Loop *L, SCEVExpander &Rewriter) {
SmallVector<WeakVH, 16> DeadInsts;
// Rewrite all induction variable expressions in terms of the canonical
// induction variable.
//
// If there were induction variables of other sizes or offsets, manually
// add the offsets to the primary induction variable and cast, avoiding
// the need for the code evaluation methods to insert induction variables
// of different sizes.
for (IVUsers::iterator UI = IU->begin(), E = IU->end(); UI != E; ++UI) {
const SCEV *Stride = UI->getStride();
Value *Op = UI->getOperandValToReplace();
const Type *UseTy = Op->getType();
Instruction *User = UI->getUser();
// Compute the final addrec to expand into code.
const SCEV *AR = IU->getReplacementExpr(*UI);
// Evaluate the expression out of the loop, if possible.
if (!L->contains(UI->getUser())) {
const SCEV *ExitVal = SE->getSCEVAtScope(AR, L->getParentLoop());
if (ExitVal->isLoopInvariant(L))
AR = ExitVal;
}
// FIXME: It is an extremely bad idea to indvar substitute anything more
// complex than affine induction variables. Doing so will put expensive
// polynomial evaluations inside of the loop, and the str reduction pass
// currently can only reduce affine polynomials. For now just disable
// indvar subst on anything more complex than an affine addrec, unless
// it can be expanded to a trivial value.
if (!AR->isLoopInvariant(L) && !Stride->isLoopInvariant(L))
continue;
// Determine the insertion point for this user. By default, insert
// immediately before the user. The SCEVExpander class will automatically
// hoist loop invariants out of the loop. For PHI nodes, there may be
// multiple uses, so compute the nearest common dominator for the
// incoming blocks.
Instruction *InsertPt = User;
if (PHINode *PHI = dyn_cast<PHINode>(InsertPt))
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i)
if (PHI->getIncomingValue(i) == Op) {
if (InsertPt == User)
InsertPt = PHI->getIncomingBlock(i)->getTerminator();
else
InsertPt =
DT->findNearestCommonDominator(InsertPt->getParent(),
PHI->getIncomingBlock(i))
->getTerminator();
}
// Now expand it into actual Instructions and patch it into place.
Value *NewVal = Rewriter.expandCodeFor(AR, UseTy, InsertPt);
// Patch the new value into place.
if (Op->hasName())
NewVal->takeName(Op);
User->replaceUsesOfWith(Op, NewVal);
UI->setOperandValToReplace(NewVal);
DEBUG(dbgs() << "INDVARS: Rewrote IV '" << *AR << "' " << *Op << '\n'
<< " into = " << *NewVal << "\n");
++NumRemoved;
Changed = true;
// The old value may be dead now.
DeadInsts.push_back(Op);
}
// Clear the rewriter cache, because values that are in the rewriter's cache
// can be deleted in the loop below, causing the AssertingVH in the cache to
// trigger.
Rewriter.clear();
// Now that we're done iterating through lists, clean up any instructions
// which are now dead.
while (!DeadInsts.empty())
if (Instruction *Inst =
dyn_cast_or_null<Instruction>(DeadInsts.pop_back_val()))
RecursivelyDeleteTriviallyDeadInstructions(Inst);
}