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llvm-project/llvm/test/Transforms/Util/clone-dicompileunit.ll

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IR: Consider two DISubprograms to be odr-equal if they have the same template parameters. In ValueMapper we create new operands for MDNodes and rely on MDNode::replaceWithUniqued to create a new MDNode with the specified operands. However this doesn't always actually happen correctly for DISubprograms because when we uniquify the new node, we only odr-compare it with existing nodes (MDNodeSubsetEqualImpl<DISubprogram>::isDeclarationOfODRMember). Although the TemplateParameters field can refer to a distinct DICompileUnit via DITemplateTypeParameter::type -> DICompositeType::scope -> DISubprogram::unit, it is not currently included in the odr comparison. As a result, we can end up getting our original DISubprogram back, which means we will have a cloned module referring to the DICompileUnit in the original module, which causes a verification error. The fix I implemented was to consider TemplateParameters to be one of the odr-equal properties. But I'm a little uncomfortable with this. In general it seems unsound to rely on distinct MDNodes never being reachable from nodes which we only check odr-equality of. My only long term suggestion would be to separate odr-uniquing from full uniquing. Differential Revision: https://reviews.llvm.org/D29240 llvm-svn: 294240
2017-02-07 05:23:03 +08:00
; RUN: opt -run-twice -verify -disable-debug-info-type-map -S -o - %s | FileCheck %s
; Generated using:
; $ cat p.cpp
; void sink(void *);
; class A {
; public:
; template <typename> void m_fn2() { static int a; }
; virtual void m_fn1();
; };
; void foo() {
; class B : public A {
; public:
; B() { m_fn2<B>(); }
; };
; sink(new B);
; }
; $ clang++ -target x86_64-unknown-linux -fvisibility=hidden -O2 -g2 -flto -S p.cpp -o p.ll
; # then manually removed function/gv definitions
; Test that when the module is cloned it does not contain a reference to
; the original DICompileUnit as a result of a collision between the cloned
; DISubprogram for m_fn2<B> (which refers to the non-ODR entity B via
; template parameters) and the original DISubprogram.
; CHECK: DICompileUnit
; CHECK-NOT: DICompileUnit
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux"
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!28, !29}
!llvm.ident = !{!30}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 5.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
!1 = !DIFile(filename: "p.cpp", directory: "/usr/local/google/home/pcc/b682773-2-repro/small2")
!2 = !{}
!3 = !{!4}
Canonicalize the representation of empty an expression in DIGlobalVariableExpression This change simplifies code that has to deal with DIGlobalVariableExpression and mirrors how we treat DIExpressions in debug info intrinsics. Before this change there were two ways of representing empty expressions on globals, a nullptr and an empty !DIExpression(). If someone needs to upgrade out-of-tree testcases: perl -pi -e 's/(!DIGlobalVariableExpression\(var: ![0-9]*)\)/\1, expr: !DIExpression())/g' <MYTEST.ll> will catch 95%. llvm-svn: 312144
2017-08-31 02:06:51 +08:00
!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
IR: Consider two DISubprograms to be odr-equal if they have the same template parameters. In ValueMapper we create new operands for MDNodes and rely on MDNode::replaceWithUniqued to create a new MDNode with the specified operands. However this doesn't always actually happen correctly for DISubprograms because when we uniquify the new node, we only odr-compare it with existing nodes (MDNodeSubsetEqualImpl<DISubprogram>::isDeclarationOfODRMember). Although the TemplateParameters field can refer to a distinct DICompileUnit via DITemplateTypeParameter::type -> DICompositeType::scope -> DISubprogram::unit, it is not currently included in the odr comparison. As a result, we can end up getting our original DISubprogram back, which means we will have a cloned module referring to the DICompileUnit in the original module, which causes a verification error. The fix I implemented was to consider TemplateParameters to be one of the odr-equal properties. But I'm a little uncomfortable with this. In general it seems unsound to rely on distinct MDNodes never being reachable from nodes which we only check odr-equality of. My only long term suggestion would be to separate odr-uniquing from full uniquing. Differential Revision: https://reviews.llvm.org/D29240 llvm-svn: 294240
2017-02-07 05:23:03 +08:00
!5 = distinct !DIGlobalVariable(name: "a", scope: !6, file: !1, line: 5, type: !27, isLocal: true, isDefinition: true)
!6 = distinct !DISubprogram(name: "m_fn2<B>", linkageName: "_ZN1A5m_fn2IZ3foovE1BEEvv", scope: !7, file: !1, line: 5, type: !8, isLocal: true, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, unit: !0, templateParams: !11, declaration: !23, variables: !24)
!7 = !DICompositeType(tag: DW_TAG_class_type, name: "A", file: !1, line: 3, flags: DIFlagFwdDecl, identifier: "_ZTS1A")
!8 = !DISubroutineType(types: !9)
!9 = !{null, !10}
!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !7, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
!11 = !{!12}
!12 = !DITemplateTypeParameter(type: !13)
!13 = distinct !DICompositeType(tag: DW_TAG_class_type, name: "B", scope: !14, file: !1, line: 10, size: 64, elements: !17, vtableHolder: !7)
!14 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 9, type: !15, isLocal: false, isDefinition: true, scopeLine: 9, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
!15 = !DISubroutineType(types: !16)
!16 = !{null}
!17 = !{!18, !19}
!18 = !DIDerivedType(tag: DW_TAG_inheritance, scope: !13, baseType: !7, flags: DIFlagPublic)
!19 = !DISubprogram(name: "B", scope: !13, file: !1, line: 12, type: !20, isLocal: false, isDefinition: false, scopeLine: 12, flags: DIFlagPublic | DIFlagPrototyped, isOptimized: true)
!20 = !DISubroutineType(types: !21)
!21 = !{null, !22}
!22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
!23 = !DISubprogram(name: "m_fn2<B>", linkageName: "_ZN1A5m_fn2IZ3foovE1BEEvv", scope: !7, file: !1, line: 5, type: !8, isLocal: false, isDefinition: false, scopeLine: 5, flags: DIFlagPublic | DIFlagPrototyped, isOptimized: true, templateParams: !11)
!24 = !{!25}
!25 = !DILocalVariable(name: "this", arg: 1, scope: !6, type: !26, flags: DIFlagArtificial | DIFlagObjectPointer)
!26 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !7, size: 64)
!27 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!28 = !{i32 2, !"Dwarf Version", i32 4}
!29 = !{i32 2, !"Debug Info Version", i32 3}
!30 = !{!"clang version 5.0.0 "}