Utils: Keep distinct MDNodes distinct in MapMetadata()

Create new copies of distinct `MDNode`s instead of following the
uniquing `MDNode` logic.

Just like self-references (or other cycles), `MapMetadata()` creates a
new node.  In practice most calls use `RF_NoModuleLevelChanges`, in
which case nothing is duplicated anyway.

Part of PR22111.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225476 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan P. N. Exon Smith 2015-01-08 22:42:30 +00:00
parent f416d72973
commit 3408708548
3 changed files with 64 additions and 0 deletions

View File

@ -212,6 +212,20 @@ static Metadata *MapMetadataImpl(const Metadata *MD, ValueToValueMapTy &VM,
if (Flags & RF_NoModuleLevelChanges)
return mapToSelf(VM, MD);
// Distinct nodes are always recreated.
if (Node->isDistinct()) {
// Create the node first so it's available for cyclical references.
SmallVector<Metadata *, 4> EmptyOps(Node->getNumOperands());
MDNode *NewMD = MDNode::getDistinct(Node->getContext(), EmptyOps);
mapToMetadata(VM, Node, NewMD);
// Fix the operands.
for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I)
NewMD->replaceOperandWith(I, getMappedOp(Node->getOperand(I)));
return NewMD;
}
// Create a dummy node in case we have a metadata cycle.
MDNodeFwdDecl *Dummy = MDNode::getTemporary(Node->getContext(), None);
mapToMetadata(VM, Node, Dummy);

View File

@ -0,0 +1,13 @@
@global = linkonce global i32 0
!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8}
!0 = !{}
!1 = !{!0}
!2 = !{i32* @global}
!3 = distinct !{}
!4 = distinct !{!0}
!5 = distinct !{i32* @global}
!6 = !{!3}
!7 = !{!4}
!8 = !{!5}

37
test/Linker/distinct.ll Normal file
View File

@ -0,0 +1,37 @@
; RUN: llvm-link %s %S/Inputs/distinct.ll -o - -S | FileCheck %s
; Test that distinct nodes from other modules remain distinct. The @global
; cases are the most interesting, since the operands actually need to be
; remapped.
; CHECK: @global = linkonce global i32 0
@global = linkonce global i32 0
; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !0, !1, !2, !9, !10, !11, !12, !13, !14}
!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8}
; CHECK: !0 = !{}
; CHECK-NEXT: !1 = !{!0}
; CHECK-NEXT: !2 = !{i32* @global}
; CHECK-NEXT: !3 = distinct !{}
; CHECK-NEXT: !4 = distinct !{!0}
; CHECK-NEXT: !5 = distinct !{i32* @global}
; CHECK-NEXT: !6 = !{!3}
; CHECK-NEXT: !7 = !{!4}
; CHECK-NEXT: !8 = !{!5}
; CHECK-NEXT: !9 = distinct !{}
; CHECK-NEXT: !10 = distinct !{!0}
; CHECK-NEXT: !11 = distinct !{i32* @global}
; CHECK-NEXT: !12 = !{!9}
; CHECK-NEXT: !13 = !{!10}
; CHECK-NEXT: !14 = !{!11}
; CHECK-NOT: !
!0 = !{}
!1 = !{!0}
!2 = !{i32* @global}
!3 = distinct !{}
!4 = distinct !{!0}
!5 = distinct !{i32* @global}
!6 = !{!3}
!7 = !{!4}
!8 = !{!5}