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Utils: Resolve cycles under distinct MDNodes

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Track unresolved nodes under distinct `MDNode`s during `MapMetadata()`,
and resolve them at the end.  Previously, these cycles wouldn't get
resolved.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228180 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan P. N. Exon Smith 2015-02-04 19:44:34 +00:00
parent a602c10686
commit a7a6be22eb
2 changed files with 58 additions and 20 deletions
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65
lib/Transforms/Utils/ValueMapper.cpp
View File

@ -154,19 +154,20 @@ static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
}
static Metadata *MapMetadataImpl(const Metadata *MD, ValueToValueMapTy &VM,
RemapFlags Flags,
static Metadata *MapMetadataImpl(const Metadata *MD,
SmallVectorImpl<MDNode *> &Cycles,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer);
static Metadata *mapMetadataOp(Metadata *Op, ValueToValueMapTy &VM,
RemapFlags Flags,
static Metadata *mapMetadataOp(Metadata *Op, SmallVectorImpl<MDNode *> &Cycles,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
if (!Op)
return nullptr;
if (Metadata *MappedOp =
MapMetadataImpl(Op, VM, Flags, TypeMapper, Materializer))
MapMetadataImpl(Op, Cycles, VM, Flags, TypeMapper, Materializer))
return MappedOp;
// Use identity map if MappedOp is null and we can ignore missing entries.
if (Flags & RF_IgnoreMissingEntries)
@ -186,7 +187,8 @@ static Metadata *mapMetadataOp(Metadata *Op, ValueToValueMapTy &VM,
/// Assumes that \c NewNode is already a clone of \c OldNode.
///
/// \pre \c NewNode is a clone of \c OldNode.
static bool remap(const MDNode *OldNode, MDNode *NewNode, ValueToValueMapTy &VM,
static bool remap(const MDNode *OldNode, MDNode *NewNode,
SmallVectorImpl<MDNode *> &Cycles, ValueToValueMapTy &VM,
RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
assert(OldNode->getNumOperands() == NewNode->getNumOperands() &&
@ -202,8 +204,8 @@ static bool remap(const MDNode *OldNode, MDNode *NewNode, ValueToValueMapTy &VM,
assert(NewNode->getOperand(I) == Old &&
"Expected old operands to already be in place");
Metadata *New = mapMetadataOp(OldNode->getOperand(I), VM, Flags, TypeMapper,
Materializer);
Metadata *New = mapMetadataOp(OldNode->getOperand(I), Cycles, VM, Flags,
TypeMapper, Materializer);
if (Old != New) {
AnyChanged = true;
NewNode->replaceOperandWith(I, New);
@ -216,29 +218,38 @@ static bool remap(const MDNode *OldNode, MDNode *NewNode, ValueToValueMapTy &VM,
/// \brief Map a distinct MDNode.
///
/// Distinct nodes are not uniqued, so they must always recreated.
static Metadata *mapDistinctNode(const MDNode *Node, ValueToValueMapTy &VM,
RemapFlags Flags,
static Metadata *mapDistinctNode(const MDNode *Node,
SmallVectorImpl<MDNode *> &Cycles,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
assert(Node->isDistinct() && "Expected distinct node");
MDNode *NewMD = MDNode::replaceWithDistinct(Node->clone());
remap(Node, NewMD, VM, Flags, TypeMapper, Materializer);
remap(Node, NewMD, Cycles, VM, Flags, TypeMapper, Materializer);
// Track any cycles beneath this node.
for (Metadata *Op : NewMD->operands())
if (auto *Node = dyn_cast_or_null<MDNode>(Op))
if (!Node->isResolved())
Cycles.push_back(Node);
return NewMD;
}
/// \brief Map a uniqued MDNode.
///
/// Uniqued nodes may not need to be recreated (they may map to themselves).
static Metadata *mapUniquedNode(const MDNode *Node, ValueToValueMapTy &VM,
RemapFlags Flags,
static Metadata *mapUniquedNode(const MDNode *Node,
SmallVectorImpl<MDNode *> &Cycles,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
assert(Node->isUniqued() && "Expected uniqued node");
// Create a temporary node upfront in case we have a metadata cycle.
auto ClonedMD = Node->clone();
if (!remap(Node, ClonedMD.get(), VM, Flags, TypeMapper, Materializer))
if (!remap(Node, ClonedMD.get(), Cycles, VM, Flags, TypeMapper, Materializer))
// No operands changed, so use the identity mapping.
return mapToSelf(VM, Node);
@ -247,8 +258,9 @@ static Metadata *mapUniquedNode(const MDNode *Node, ValueToValueMapTy &VM,
MDNode::replaceWithUniqued(std::move(ClonedMD)));
}
static Metadata *MapMetadataImpl(const Metadata *MD, ValueToValueMapTy &VM,
RemapFlags Flags,
static Metadata *MapMetadataImpl(const Metadata *MD,
SmallVectorImpl<MDNode *> &Cycles,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
// If the value already exists in the map, use it.
@ -288,19 +300,32 @@ static Metadata *MapMetadataImpl(const Metadata *MD, ValueToValueMapTy &VM,
return mapToSelf(VM, MD);
if (Node->isDistinct())
return mapDistinctNode(Node, VM, Flags, TypeMapper, Materializer);
return mapDistinctNode(Node, Cycles, VM, Flags, TypeMapper, Materializer);
return mapUniquedNode(Node, VM, Flags, TypeMapper, Materializer);
return mapUniquedNode(Node, Cycles, VM, Flags, TypeMapper, Materializer);
}
Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
Metadata *NewMD = MapMetadataImpl(MD, VM, Flags, TypeMapper, Materializer);
if (NewMD && NewMD != MD)
SmallVector<MDNode *, 8> Cycles;
Metadata *NewMD =
MapMetadataImpl(MD, Cycles, VM, Flags, TypeMapper, Materializer);
// Resolve cycles underneath MD.
if (NewMD && NewMD != MD) {
if (auto *N = dyn_cast<MDNode>(NewMD))
if (!N->isResolved())
N->resolveCycles();
for (MDNode *N : Cycles)
if (!N->isResolved())
N->resolveCycles();
} else {
// Shouldn't get unresolved cycles if nothing was remapped.
assert(Cycles.empty() && "Expected no unresolved cycles");
}
return NewMD;
}

13
test/Linker/distinct-cycles.ll Normal file
View File

@ -0,0 +1,13 @@
; RUN: llvm-link -o - -S %s | FileCheck %s
; Crasher for PR22456: MapMetadata() should resolve all cycles.
; CHECK: !named = !{!0}
!named = !{!0}
; CHECK: !0 = distinct !{!1}
!0 = distinct !{!1}
; CHECK-NEXT: !1 = !{!2}
; CHECK-NEXT: !2 = !{!1}
!1 = !{!2}
!2 = !{!1}