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[Annotate][DLCov] Annotate intentionally-blank DebugLocs in existing code
Following the work in PR llvm#107279, this patch applies the annotative DebugLocs, which indicate that a particular instruction is intentionally missing a location for a given reason, to existing sites in the compiler where their conditions apply. This is a no-op in ordinary LLVM builds (each function `get<Type>` simply expands to `DebugLoc()`), but marks the instruction in coverage-tracking builds so that it will be ignored by Debugify, allowing only real errors to be reported. From a developer standpoint, it also communicates the intentionality and reason for a missing DebugLoc.
1 parent 9c52b3c commit 0705143

19 files changed

+80
-36
lines changed

‎llvm/lib/Transforms/IPO/GlobalOpt.cpp

Lines changed: 8 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1494,8 +1494,14 @@ processInternalGlobal(GlobalVariable *GV, const GlobalStatus &GS,
14941494
// FIXME: Pass Global's alignment when globals have alignment
14951495
AllocaInst *Alloca = new AllocaInst(ElemTy, DL.getAllocaAddrSpace(),
14961496
nullptr, GV->getName(), FirstI);
1497-
if (!isa<UndefValue>(GV->getInitializer()))
1498-
new StoreInst(GV->getInitializer(), Alloca, FirstI);
1497+
Alloca->setDebugLoc(DebugLoc::getCompilerGenerated());
1498+
if (!isa<UndefValue>(GV->getInitializer())) {
1499+
auto *SI = new StoreInst(GV->getInitializer(), Alloca, FirstI);
1500+
// FIXME: We're localizing a global and creating a store instruction for
1501+
// the initial value of that global. Could we logically use the global
1502+
// variable's (if one exists) line for this?
1503+
SI->setDebugLoc(DebugLoc::getCompilerGenerated());
1504+
}
14991505

15001506
GV->replaceAllUsesWith(Alloca);
15011507
GV->eraseFromParent();

‎llvm/lib/Transforms/IPO/IROutliner.cpp

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -730,7 +730,7 @@ static void moveFunctionData(Function &Old, Function &New,
730730
// other outlined instructions.
731731
if (!isa<CallInst>(&Val)) {
732732
// Remove the debug information for outlined functions.
733-
Val.setDebugLoc(DebugLoc());
733+
Val.setDebugLoc(DebugLoc::getDropped());
734734

735735
// Loop info metadata may contain line locations. Update them to have no
736736
// value in the new subprogram since the outlined code could be from
@@ -1864,7 +1864,7 @@ replaceArgumentUses(OutlinableRegion &Region,
18641864
Value *ValueOperand = SI->getValueOperand();
18651865

18661866
StoreInst *NewI = cast<StoreInst>(I->clone());
1867-
NewI->setDebugLoc(DebugLoc());
1867+
NewI->setDebugLoc(DebugLoc::getDropped());
18681868
BasicBlock *OutputBB = VBBIt->second;
18691869
NewI->insertInto(OutputBB, OutputBB->end());
18701870
LLVM_DEBUG(dbgs() << "Move store for instruction " << *I << " to "

‎llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -870,7 +870,14 @@ Instruction *InstCombinerImpl::foldPHIArgZextsIntoPHI(PHINode &Phi) {
870870
NewPhi->addIncoming(NewIncoming[I], Phi.getIncomingBlock(I));
871871

872872
InsertNewInstBefore(NewPhi, Phi.getIterator());
873-
return CastInst::CreateZExtOrBitCast(NewPhi, Phi.getType());
873+
auto *CI = CastInst::CreateZExtOrBitCast(NewPhi, Phi.getType());
874+
875+
// We use a dropped location here because the new ZExt is necessarily a merge
876+
// of ZExtInsts and at least one constant from incoming branches; the presence
877+
// of the constant means we have no viable DebugLoc from that branch, and
878+
// therefore we must use a dropped location.
879+
CI->setDebugLoc(DebugLoc::getDropped());
880+
return CI;
874881
}
875882

876883
/// If all operands to a PHI node are the same "unary" operator and they all are

‎llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -432,7 +432,8 @@ static bool processSwitch(SwitchInst *I, LazyValueInfo *LVI,
432432
BasicBlock *NewUnreachableBB =
433433
BasicBlock::Create(BB->getContext(), "default.unreachable",
434434
BB->getParent(), DefaultDest);
435-
new UnreachableInst(BB->getContext(), NewUnreachableBB);
435+
auto *UI = new UnreachableInst(BB->getContext(), NewUnreachableBB);
436+
UI->setDebugLoc(DebugLoc::getTemporary());
436437

437438
DefaultDest->removePredecessor(BB);
438439
SI->setDefaultDest(NewUnreachableBB);

‎llvm/lib/Transforms/Scalar/IndVarSimplify.cpp

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1506,6 +1506,7 @@ bool IndVarSimplify::canonicalizeExitCondition(Loop *L) {
15061506
auto *NewRHS = CastInst::Create(
15071507
Instruction::Trunc, RHS, LHSOp->getType(), "",
15081508
L->getLoopPreheader()->getTerminator()->getIterator());
1509+
NewRHS->setDebugLoc(DebugLoc::getDropped());
15091510
ICmp->setOperand(Swapped ? 1 : 0, LHSOp);
15101511
ICmp->setOperand(Swapped ? 0 : 1, NewRHS);
15111512
// Samesign flag cannot be preserved after narrowing the compare.

‎llvm/lib/Transforms/Scalar/JumpThreading.cpp

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3001,8 +3001,10 @@ bool JumpThreadingPass::tryToUnfoldSelectInCurrBB(BasicBlock *BB) {
30013001
continue;
30023002
// Expand the select.
30033003
Value *Cond = SI->getCondition();
3004-
if (!isGuaranteedNotToBeUndefOrPoison(Cond, nullptr, SI))
3004+
if (!isGuaranteedNotToBeUndefOrPoison(Cond, nullptr, SI)) {
30053005
Cond = new FreezeInst(Cond, "cond.fr", SI->getIterator());
3006+
cast<FreezeInst>(Cond)->setDebugLoc(DebugLoc::getTemporary());
3007+
}
30063008
MDNode *BranchWeights = getBranchWeightMDNode(*SI);
30073009
Instruction *Term =
30083010
SplitBlockAndInsertIfThen(Cond, SI, false, BranchWeights);

‎llvm/lib/Transforms/Scalar/LICM.cpp

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1722,7 +1722,7 @@ static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT,
17221722
Instruction *New = sinkThroughTriviallyReplaceablePHI(
17231723
PN, &I, LI, SunkCopies, SafetyInfo, CurLoop, MSSAU);
17241724
// As we sink the instruction out of the BB, drop its debug location.
1725-
New->dropLocation();
1725+
New->setDebugLoc(DebugLoc::getDropped());
17261726
PN->replaceAllUsesWith(New);
17271727
eraseInstruction(*PN, *SafetyInfo, MSSAU);
17281728
Changed = true;
@@ -2248,7 +2248,7 @@ bool llvm::promoteLoopAccessesToScalars(
22482248
if (SawUnorderedAtomic)
22492249
PreheaderLoad->setOrdering(AtomicOrdering::Unordered);
22502250
PreheaderLoad->setAlignment(Alignment);
2251-
PreheaderLoad->setDebugLoc(DebugLoc());
2251+
PreheaderLoad->dropLocation();
22522252
if (AATags && LoadIsGuaranteedToExecute)
22532253
PreheaderLoad->setAAMetadata(AATags);
22542254

@@ -2808,6 +2808,7 @@ static bool hoistMulAddAssociation(Instruction &I, Loop &L,
28082808
auto *NewBO =
28092809
BinaryOperator::Create(Ins->getOpcode(), LHS, RHS,
28102810
Ins->getName() + ".reass", Ins->getIterator());
2811+
NewBO->setDebugLoc(DebugLoc::getDropped());
28112812
NewBO->copyIRFlags(Ins);
28122813
if (VariantOp == Ins)
28132814
VariantOp = NewBO;
@@ -2864,6 +2865,7 @@ static bool hoistBOAssociation(Instruction &I, Loop &L,
28642865

28652866
auto *NewBO = BinaryOperator::Create(
28662867
Opcode, LV, Inv, BO->getName() + ".reass", BO->getIterator());
2868+
NewBO->setDebugLoc(DebugLoc::getDropped());
28672869

28682870
if (Opcode == Instruction::FAdd || Opcode == Instruction::FMul) {
28692871
// Intersect FMF flags for FADD and FMUL.

‎llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -442,14 +442,15 @@ class LoadEliminationForLoop {
442442
assert(PH && "Preheader should exist!");
443443
Value *InitialPtr = SEE.expandCodeFor(PtrSCEV->getStart(), Ptr->getType(),
444444
PH->getTerminator());
445-
Value *Initial =
445+
Instruction *Initial =
446446
new LoadInst(Cand.Load->getType(), InitialPtr, "load_initial",
447447
/* isVolatile */ false, Cand.Load->getAlign(),
448448
PH->getTerminator()->getIterator());
449449
// We don't give any debug location to Initial, because it is inserted
450450
// into the loop's preheader. A debug location inside the loop will cause
451451
// a misleading stepping when debugging. The test update-debugloc-store
452452
// -forwarded.ll checks this.
453+
Initial->setDebugLoc(DebugLoc::getDropped());
453454

454455
PHINode *PHI = PHINode::Create(Initial->getType(), 2, "store_forwarded");
455456
PHI->insertBefore(L->getHeader()->begin());

‎llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -274,6 +274,7 @@ static void buildPartialUnswitchConditionalBranch(
274274
BasicBlock &UnswitchedSucc, BasicBlock &NormalSucc, bool InsertFreeze,
275275
const Instruction *I, AssumptionCache *AC, const DominatorTree &DT) {
276276
IRBuilder<> IRB(&BB);
277+
IRB.SetCurrentDebugLocation(DebugLoc::getCompilerGenerated());
277278

278279
SmallVector<Value *> FrozenInvariants;
279280
for (Value *Inv : Invariants) {
@@ -330,6 +331,7 @@ static void buildPartialInvariantUnswitchConditionalBranch(
330331
}
331332

332333
IRBuilder<> IRB(&BB);
334+
IRB.SetCurrentDebugLocation(DebugLoc::getCompilerGenerated());
333335
Value *Cond = VMap[ToDuplicate[0]];
334336
IRB.CreateCondBr(Cond, Direction ? &UnswitchedSucc : &NormalSucc,
335337
Direction ? &NormalSucc : &UnswitchedSucc);
@@ -2369,6 +2371,7 @@ static void unswitchNontrivialInvariants(
23692371
// BI (`dyn_cast<BranchInst>(TI)`) is an in-loop instruction hoisted
23702372
// out of the loop.
23712373
Cond = new FreezeInst(Cond, Cond->getName() + ".fr", BI->getIterator());
2374+
cast<Instruction>(Cond)->setDebugLoc(DebugLoc::getDropped());
23722375
}
23732376
BI->setCondition(Cond);
23742377
DTUpdates.push_back({DominatorTree::Insert, SplitBB, ClonedPH});

‎llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -515,7 +515,8 @@ void TailRecursionEliminator::createTailRecurseLoopHeader(CallInst *CI) {
515515
BasicBlock *NewEntry = BasicBlock::Create(F.getContext(), "", &F, HeaderBB);
516516
NewEntry->takeName(HeaderBB);
517517
HeaderBB->setName("tailrecurse");
518-
BranchInst::Create(HeaderBB, NewEntry);
518+
auto *BI = BranchInst::Create(HeaderBB, NewEntry);
519+
BI->setDebugLoc(DebugLoc::getCompilerGenerated());
519520
// If the new branch preserves the debug location of CI, it could result in
520521
// misleading stepping, if CI is located in a conditional branch.
521522
// So, here we don't give any debug location to the new branch.
@@ -801,6 +802,7 @@ void TailRecursionEliminator::cleanupAndFinalize() {
801802
SelectInst *SI =
802803
SelectInst::Create(RetKnownPN, RetPN, RI->getOperand(0),
803804
"current.ret.tr", RI->getIterator());
805+
SI->setDebugLoc(DebugLoc::getCompilerGenerated());
804806
RetSelects.push_back(SI);
805807
RI->setOperand(0, SI);
806808
}

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