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[DebugInfo][RemoveDIs] Use autoupgrader to convert old debug-info #143452

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Merged
jmorse merged 7 commits into from
Jun 11, 2025
Merged

[DebugInfo][RemoveDIs] Use autoupgrader to convert old debug-info #143452

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8525072
[DebugInfo][RemoveDIs] Use autoupgrader to convert old debug-info
jmorse Jun 3, 2025
3021087
Formatting, fix a comment, remove cruft from test
jmorse Jun 10, 2025
8506550
Pass autoupgraded DbgRecords through pre-verifier constructor
jmorse Jun 10, 2025
d41ece6
Test for some more localisation of debug-info errors
jmorse Jun 10, 2025
add20db
Hark the herald clang-format sings...
jmorse Jun 10, 2025
4c75936
Strip cruft from another test
jmorse Jun 11, 2025
bf1e168
Spelling, and avoid an un-necessary reinterpret cast
jmorse Jun 11, 2025
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2 changes: 0 additions & 2 deletions llvm/lib/AsmParser/LLParser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8336,8 +8336,6 @@ bool LLParser::parseCall(Instruction *&Inst, PerFunctionState &PFS,
return error(CallLoc, "llvm.dbg intrinsic should not appear in a module "
"using non-intrinsic debug info");
}
if (!SeenOldDbgInfoFormat)
M->setNewDbgInfoFormatFlag(false);
SeenOldDbgInfoFormat = true;
}
CI->setAttributes(PAL);
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35 changes: 25 additions & 10 deletions llvm/lib/IR/AsmWriter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1204,16 +1204,22 @@ void SlotTracker::processFunctionMetadata(const Function &F) {
}

void SlotTracker::processDbgRecordMetadata(const DbgRecord &DR) {
// Tolerate null metadata pointers: it's a completely illegal debug record,
// but we can have faulty metadata from debug-intrinsic days being
// autoupgraded into debug records. This gets caught by the verifier, which
// then will print the faulty IR, hitting this code path.
if (const DbgVariableRecord *DVR = dyn_cast<const DbgVariableRecord>(&DR)) {
// Process metadata used by DbgRecords; we only specifically care about the
// DILocalVariable, DILocation, and DIAssignID fields, as the Value and
// Expression fields should only be printed inline and so do not use a slot.
// Note: The above doesn't apply for empty-metadata operands.
if (auto *Empty = dyn_cast<MDNode>(DVR->getRawLocation()))
CreateMetadataSlot(Empty);
CreateMetadataSlot(DVR->getRawVariable());
if (DVR->getRawVariable())
CreateMetadataSlot(DVR->getRawVariable());
if (DVR->isDbgAssign()) {
CreateMetadataSlot(cast<MDNode>(DVR->getRawAssignID()));
if (auto *AssignID = DVR->getRawAssignID())
CreateMetadataSlot(cast<MDNode>(AssignID));
if (auto *Empty = dyn_cast<MDNode>(DVR->getRawAddress()))
CreateMetadataSlot(Empty);
}
Expand All @@ -1222,7 +1228,8 @@ void SlotTracker::processDbgRecordMetadata(const DbgRecord &DR) {
} else {
llvm_unreachable("unsupported DbgRecord kind");
}
CreateMetadataSlot(DR.getDebugLoc().getAsMDNode());
if (DR.getDebugLoc())
CreateMetadataSlot(DR.getDebugLoc().getAsMDNode());
}

void SlotTracker::processInstructionMetadata(const Instruction &I) {
Expand Down Expand Up @@ -4867,22 +4874,30 @@ void AssemblyWriter::printDbgVariableRecord(const DbgVariableRecord &DVR) {
llvm_unreachable(
"Tried to print a DbgVariableRecord with an invalid LocationType!");
}

auto PrintOrNull = [&](Metadata *M) {
if (!M)
Out << "(null)";
else
WriteAsOperandInternal(Out, M, WriterCtx, true);
};

Out << "(";
WriteAsOperandInternal(Out, DVR.getRawLocation(), WriterCtx, true);
PrintOrNull(DVR.getRawLocation());
Out << ", ";
WriteAsOperandInternal(Out, DVR.getRawVariable(), WriterCtx, true);
PrintOrNull(DVR.getRawVariable());
Out << ", ";
WriteAsOperandInternal(Out, DVR.getRawExpression(), WriterCtx, true);
PrintOrNull(DVR.getRawExpression());
Out << ", ";
if (DVR.isDbgAssign()) {
WriteAsOperandInternal(Out, DVR.getRawAssignID(), WriterCtx, true);
PrintOrNull(DVR.getRawAssignID());
Out << ", ";
WriteAsOperandInternal(Out, DVR.getRawAddress(), WriterCtx, true);
PrintOrNull(DVR.getRawAddress());
Out << ", ";
WriteAsOperandInternal(Out, DVR.getRawAddressExpression(), WriterCtx, true);
PrintOrNull(DVR.getRawAddressExpression());
Out << ", ";
}
WriteAsOperandInternal(Out, DVR.getDebugLoc().getAsMDNode(), WriterCtx, true);
PrintOrNull(DVR.getDebugLoc().getAsMDNode());
Out << ")";
}

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29 changes: 21 additions & 8 deletions llvm/lib/IR/AutoUpgrade.cpp
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Expand Up @@ -1155,8 +1155,7 @@ static bool upgradeIntrinsicFunction1(Function *F, Function *&NewFn,
case 'd':
if (Name.consume_front("dbg.")) {
// Mark debug intrinsics for upgrade to new debug format.
if (CanUpgradeDebugIntrinsicsToRecords &&
F->getParent()->IsNewDbgInfoFormat) {
if (CanUpgradeDebugIntrinsicsToRecords) {
if (Name == "addr" || Name == "value" || Name == "assign" ||
Name == "declare" || Name == "label") {
// There's no function to replace these with.
Expand Down Expand Up @@ -4398,11 +4397,25 @@ static Value *upgradeAMDGCNIntrinsicCall(StringRef Name, CallBase *CI,
/// Helper to unwrap intrinsic call MetadataAsValue operands.
template <typename MDType>
static MDType *unwrapMAVOp(CallBase *CI, unsigned Op) {
if (MetadataAsValue *MAV = dyn_cast<MetadataAsValue>(CI->getArgOperand(Op)))
return dyn_cast<MDType>(MAV->getMetadata());
if (Op < CI->arg_size()) {
if (MetadataAsValue *MAV = dyn_cast<MetadataAsValue>(CI->getArgOperand(Op)))
// Use reinterpret_cast rather than dyn_cast because the autoupgrade
// process happens before the verifier, meaning we may see unexpected
// operands here.
return reinterpret_cast<MDType*>(MAV->getMetadata());
}
return nullptr;
}

static const DILocation *getDebugLocSafe(const Instruction *I) {
MDNode *MD = I->getDebugLoc().getAsMDNode();
// Use a C-style cast here rather than cast<DILocation>. The autoupgrader
// runs before the verifier, so the Metadata could refer to anything. Allow
// the verifier to detect and produce an error message, which will be much
// more ergonomic to the user.
return (const DILocation*)MD;
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@OCHyams OCHyams Jun 10, 2025

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Not 100% sure but could this be UB if MD is in fact not a DILocation? Or is that only if it's read through the ptr... I guess it's still not ideal to introduce the chance of UB...

Would it be more correct to return nullptr in that case, and allow nullptrs in DbgRecords which are checked against in the verifier (I don't like it, but not sure this is right either?). I guess the same comment applies to the reinterpret_cast above

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@jmorse jmorse Jun 10, 2025

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I feel like it's the dereference that's the problem; while my instinct is to go "It'll be fiiiinnnneeee", it turns out we've been here before, and the createUnresolvedDbgVariableRecord constructor works exactly for this purpose. I've reshuffled this code to cast to MDNodes and pass into that constructor.

What we lose out on is some error-case ergonomics: in some of the verifier tests, we now no longer have a spurious empty-string metadata printed in the middle of a DbgRecord and instead have (null). That's because the autoupgrade process drops the string reference because it's Metadata* rather than an MDNode, so it returns null. Theoretically this harms the ability to localise where a faulty debug record is in the input. However, for MDNodes we'll still pass the illegal node in and print it out, I've added a little coverage to llvm.dbg.declare-variable.ll.

I don't think this is likely to seriously harm diagnosing what's wrong with an LLVM-IR file; there are also block and function references printed to localise where the faulty record is.

}

/// Convert debug intrinsic calls to non-instruction debug records.
/// \p Name - Final part of the intrinsic name, e.g. 'value' in llvm.dbg.value.
/// \p CI - The debug intrinsic call.
Expand All @@ -4415,19 +4428,19 @@ static void upgradeDbgIntrinsicToDbgRecord(StringRef Name, CallBase *CI) {
unwrapMAVOp<Metadata>(CI, 0), unwrapMAVOp<DILocalVariable>(CI, 1),
unwrapMAVOp<DIExpression>(CI, 2), unwrapMAVOp<DIAssignID>(CI, 3),
unwrapMAVOp<Metadata>(CI, 4), unwrapMAVOp<DIExpression>(CI, 5),
CI->getDebugLoc());
getDebugLocSafe(CI));
} else if (Name == "declare") {
DR = new DbgVariableRecord(
unwrapMAVOp<Metadata>(CI, 0), unwrapMAVOp<DILocalVariable>(CI, 1),
unwrapMAVOp<DIExpression>(CI, 2), CI->getDebugLoc(),
unwrapMAVOp<DIExpression>(CI, 2), getDebugLocSafe(CI),
DbgVariableRecord::LocationType::Declare);
} else if (Name == "addr") {
// Upgrade dbg.addr to dbg.value with DW_OP_deref.
DIExpression *Expr = unwrapMAVOp<DIExpression>(CI, 2);
Expr = DIExpression::append(Expr, dwarf::DW_OP_deref);
DR = new DbgVariableRecord(unwrapMAVOp<Metadata>(CI, 0),
unwrapMAVOp<DILocalVariable>(CI, 1), Expr,
CI->getDebugLoc());
getDebugLocSafe(CI));
} else if (Name == "value") {
// An old version of dbg.value had an extra offset argument.
unsigned VarOp = 1;
Expand All @@ -4442,7 +4455,7 @@ static void upgradeDbgIntrinsicToDbgRecord(StringRef Name, CallBase *CI) {
}
DR = new DbgVariableRecord(
unwrapMAVOp<Metadata>(CI, 0), unwrapMAVOp<DILocalVariable>(CI, VarOp),
unwrapMAVOp<DIExpression>(CI, ExprOp), CI->getDebugLoc());
unwrapMAVOp<DIExpression>(CI, ExprOp), getDebugLocSafe(CI));
}
assert(DR && "Unhandled intrinsic kind in upgrade to DbgRecord");
CI->getParent()->insertDbgRecordBefore(DR, CI->getIterator());
Expand Down
4 changes: 0 additions & 4 deletions llvm/lib/IR/BasicBlock.cpp
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Expand Up @@ -32,8 +32,6 @@ using namespace llvm;
STATISTIC(NumInstrRenumberings, "Number of renumberings across all blocks");

DbgMarker *BasicBlock::createMarker(Instruction *I) {
assert(IsNewDbgInfoFormat &&
"Tried to create a marker in a non new debug-info block!");
if (I->DebugMarker)
return I->DebugMarker;
DbgMarker *Marker = new DbgMarker();
Expand All @@ -43,8 +41,6 @@ DbgMarker *BasicBlock::createMarker(Instruction *I) {
}

DbgMarker *BasicBlock::createMarker(InstListType::iterator It) {
assert(IsNewDbgInfoFormat &&
"Tried to create a marker in a non new debug-info block!");
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@OCHyams OCHyams Jun 10, 2025

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Are the IsNewDbgInfoFormat deletions (here and in the unittest) from a different patch in the series?

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@jmorse jmorse Jun 10, 2025

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I did actually hit this while developing this patch; LLParser was setting the flag to false, then Autoupgrade, upon upgrading, would create a marker and hit this assertion. Deleting the assertion (as the flag should be true everywhere anyway) was part of that process.

(Technically this could be taken out of this patch now as there's nothing setting the flag to false, anywhere, but it's got to be deleted at some point).

if (It != end())
return createMarker(&*It);
DbgMarker *DM = getTrailingDbgRecords();
Expand Down
24 changes: 12 additions & 12 deletions llvm/lib/IR/Verifier.cpp
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Expand Up @@ -6710,38 +6710,38 @@ void Verifier::visit(DbgVariableRecord &DVR) {
CheckDI(DVR.getType() == DbgVariableRecord::LocationType::Value ||
DVR.getType() == DbgVariableRecord::LocationType::Declare ||
DVR.getType() == DbgVariableRecord::LocationType::Assign,
"invalid #dbg record type", &DVR, DVR.getType());
"invalid #dbg record type", &DVR, DVR.getType(), BB, F);

// The location for a DbgVariableRecord must be either a ValueAsMetadata,
// DIArgList, or an empty MDNode (which is a legacy representation for an
// "undef" location).
auto *MD = DVR.getRawLocation();
CheckDI(MD && (isa<ValueAsMetadata>(MD) || isa<DIArgList>(MD) ||
(isa<MDNode>(MD) && !cast<MDNode>(MD)->getNumOperands())),
"invalid #dbg record address/value", &DVR, MD);
"invalid #dbg record address/value", &DVR, MD, BB, F);
if (auto *VAM = dyn_cast<ValueAsMetadata>(MD)) {
visitValueAsMetadata(*VAM, F);
if (DVR.isDbgDeclare()) {
// Allow integers here to support inttoptr salvage.
Type *Ty = VAM->getValue()->getType();
CheckDI(Ty->isPointerTy() || Ty->isIntegerTy(),
"location of #dbg_declare must be a pointer or int", &DVR, MD);
"location of #dbg_declare must be a pointer or int", &DVR, MD, BB, F);
}
} else if (auto *AL = dyn_cast<DIArgList>(MD)) {
visitDIArgList(*AL, F);
}

CheckDI(isa_and_nonnull<DILocalVariable>(DVR.getRawVariable()),
"invalid #dbg record variable", &DVR, DVR.getRawVariable());
"invalid #dbg record variable", &DVR, DVR.getRawVariable(), BB, F);
visitMDNode(*DVR.getRawVariable(), AreDebugLocsAllowed::No);

CheckDI(isa_and_nonnull<DIExpression>(DVR.getRawExpression()),
"invalid #dbg record expression", &DVR, DVR.getRawExpression());
"invalid #dbg record expression", &DVR, DVR.getRawExpression(), BB, F);
visitMDNode(*DVR.getExpression(), AreDebugLocsAllowed::No);

if (DVR.isDbgAssign()) {
CheckDI(isa_and_nonnull<DIAssignID>(DVR.getRawAssignID()),
"invalid #dbg_assign DIAssignID", &DVR, DVR.getRawAssignID());
"invalid #dbg_assign DIAssignID", &DVR, DVR.getRawAssignID(), BB, F);
visitMDNode(*cast<DIAssignID>(DVR.getRawAssignID()),
AreDebugLocsAllowed::No);

Expand All @@ -6752,29 +6752,29 @@ void Verifier::visit(DbgVariableRecord &DVR) {
CheckDI(
isa<ValueAsMetadata>(RawAddr) ||
(isa<MDNode>(RawAddr) && !cast<MDNode>(RawAddr)->getNumOperands()),
"invalid #dbg_assign address", &DVR, DVR.getRawAddress());
"invalid #dbg_assign address", &DVR, DVR.getRawAddress(), BB, F);
if (auto *VAM = dyn_cast<ValueAsMetadata>(RawAddr))
visitValueAsMetadata(*VAM, F);

CheckDI(isa_and_nonnull<DIExpression>(DVR.getRawAddressExpression()),
"invalid #dbg_assign address expression", &DVR,
DVR.getRawAddressExpression());
DVR.getRawAddressExpression(), BB, F);
visitMDNode(*DVR.getAddressExpression(), AreDebugLocsAllowed::No);

// All of the linked instructions should be in the same function as DVR.
for (Instruction *I : at::getAssignmentInsts(&DVR))
CheckDI(DVR.getFunction() == I->getFunction(),
"inst not in same function as #dbg_assign", I, &DVR);
"inst not in same function as #dbg_assign", I, &DVR, BB, F);
}

// This check is redundant with one in visitLocalVariable().
DILocalVariable *Var = DVR.getVariable();
CheckDI(isType(Var->getRawType()), "invalid type ref", Var,
Var->getRawType());
Var->getRawType(), BB, F);

auto *DLNode = DVR.getDebugLoc().getAsMDNode();
CheckDI(isa_and_nonnull<DILocation>(DLNode), "invalid #dbg record DILocation",
&DVR, DLNode);
&DVR, DLNode, BB, F);
DILocation *Loc = DVR.getDebugLoc();

// The scopes for variables and !dbg attachments must agree.
Expand All @@ -6786,7 +6786,7 @@ void Verifier::visit(DbgVariableRecord &DVR) {
CheckDI(VarSP == LocSP,
"mismatched subprogram between #dbg record variable and DILocation",
&DVR, BB, F, Var, Var->getScope()->getSubprogram(), Loc,
Loc->getScope()->getSubprogram());
Loc->getScope()->getSubprogram(), BB, F);

verifyFnArgs(DVR);
}
Expand Down
6 changes: 5 additions & 1 deletion llvm/test/Assembler/drop-debug-info-nonzero-alloca.ll
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Expand Up @@ -12,8 +12,12 @@ entry:
metadata ptr undef,
metadata !DILocalVariable(scope: !1),
metadata !DIExpression())
; AS: llvm.dbg.value intrinsic requires a !dbg attachment
; AS: invalid #dbg record DILocation
; AS: #dbg_value(ptr undef, !{{[0-9]+}}, !DIExpression(), (null))
; AS: label %entry
; AS: ptr @foo
; AS: warning: ignoring invalid debug info in <stdin>

ret void
}

Expand Down
18 changes: 9 additions & 9 deletions llvm/test/DebugInfo/Generic/assignment-tracking/parse-and-verify/verify.ll
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Expand Up @@ -8,7 +8,7 @@

define dso_local void @fun2() !dbg !15 {
;; DIAssignID copied here from @fun() where it is used by intrinsics.
; CHECK: dbg.assign not in same function as inst
; CHECK: DVRAssign not in same function as inst
%x = alloca i32, align 4, !DIAssignID !14
ret void
}
Expand All @@ -17,24 +17,24 @@ define dso_local void @fun() !dbg !7 {
entry:
%a = alloca i32, align 4, !DIAssignID !14
;; Here something other than a dbg.assign intrinsic is using a DIAssignID.
; CHECK: !DIAssignID should only be used by llvm.dbg.assign intrinsics
; CHECK: !DIAssignID should only be used by Assign DVRs
call void @llvm.dbg.value(metadata !14, metadata !10, metadata !DIExpression()), !dbg !13

;; Each following dbg.assign has an argument of the incorrect type.
; CHECK: invalid llvm.dbg.assign intrinsic address/value
; CHECK: invalid #dbg record address/value
call void @llvm.dbg.assign(metadata !3, metadata !10, metadata !DIExpression(), metadata !14, metadata ptr undef, metadata !DIExpression()), !dbg !13
; CHECK: invalid llvm.dbg.assign intrinsic variable
; CHECK: invalid #dbg record variable
call void @llvm.dbg.assign(metadata i32 0, metadata !2, metadata !DIExpression(), metadata !14, metadata ptr undef, metadata !DIExpression()), !dbg !13
; CHECK: invalid llvm.dbg.assign intrinsic expression
; CHECK: invalid #dbg record expression
call void @llvm.dbg.assign(metadata !14, metadata !10, metadata !2, metadata !14, metadata ptr undef, metadata !DIExpression()), !dbg !13
; CHECK: invalid llvm.dbg.assign intrinsic DIAssignID
; CHECK: invalid #dbg_assign DIAssignID
call void @llvm.dbg.assign(metadata !14, metadata !10, metadata !DIExpression(), metadata !2, metadata ptr undef, metadata !DIExpression()), !dbg !13
; CHECK: invalid llvm.dbg.assign intrinsic address
; CHECK: invalid #dbg_assign address
call void @llvm.dbg.assign(metadata !14, metadata !10, metadata !DIExpression(), metadata !14, metadata !3, metadata !DIExpression()), !dbg !13
;; Empty metadata debug operands are allowed.
; CHECK-NOT: invalid llvm.dbg.assign
; CHECK-NOT: invalid #dbg record
call void @llvm.dbg.assign(metadata !14, metadata !10, metadata !DIExpression(), metadata !14, metadata !2, metadata !DIExpression()), !dbg !13
; CHECK: invalid llvm.dbg.assign intrinsic address expression
; CHECK: invalid #dbg_assign address expression
call void @llvm.dbg.assign(metadata !14, metadata !10, metadata !DIExpression(), metadata !14, metadata ptr undef, metadata !2), !dbg !13
ret void
}
Expand Down
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