Commit 04aa3b87 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r287353: 

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r287353 | hans | 2016-11-18 09:33:05 -0800 (Fri, 18 Nov 2016) | 12 lines

IRMover: Avoid accidentally mapping types from the destination module (PR30799)

During Module linking, it's possible for SrcM->getIdentifiedStructTypes();
to return types that are actually defined in the destination module
(DstM). Depending on how the bitcode file was read,
getIdentifiedStructTypes() might do a walk over all values, including
metadata nodes, looking for types. In my case, a debug info metadata
node was shared between the two modules, and it referred to a type
defined in the destination module (see test case).

Differential Revision: https://reviews.llvm.org/D26212

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llvm-svn: 287906
parent cdf53e33

llvm/lib/Linker/IRMover.cpp

+8 −0
Original line number Diff line number Diff line
@@ -694,6 +694,14 @@ void IRLinker::computeTypeMapping() { 
    if (!ST->hasName())

      continue;



    if (TypeMap.DstStructTypesSet.hasType(ST)) {

      // This is actually a type from the destination module.

      // getIdentifiedStructTypes() can have found it by walking debug info

      // metadata nodes, some of which get linked by name when ODR Type Uniquing

      // is enabled on the Context, from the source to the destination module.

      continue;

    }



    // Check to see if there is a dot in the name followed by a digit.

    size_t DotPos = ST->getName().rfind('.');

    if (DotPos == 0 || DotPos == StringRef::npos ||

llvm/test/LTO/X86/Inputs/type-mapping-src.ll

0 → 100644
+20 −0
Original line number Diff line number Diff line 
target triple = "x86_64-pc-windows-msvc18.0.0"



%SrcType = type { i8 }

@x = external global %SrcType



%CommonStruct = type opaque

@bar = internal global %CommonStruct* null, !dbg !0





!llvm.dbg.cu = !{!1}

!llvm.module.flags = !{!12}

!0 = distinct !DIGlobalVariable(name: "bar", linkageName: "bar", scope: !1, file: !2, line: 2, type: !5, isLocal: false, isDefinition: true)

!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, globals: !4)

!2 = !DIFile(filename: "b", directory: "/")

!3 = !{}

!4 = !{!0}

!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)

!6 = !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !2, line: 1, flags: DIFlagFwdDecl, identifier: ".?AUS@@")

!12 = !{i32 2, !"Debug Info Version", i32 3}

llvm/test/LTO/X86/type-mapping-bug.ll

0 → 100644
+50 −0
Original line number Diff line number Diff line 
; RUN: llvm-as -o %t.dst.bc %s

; RUN: llvm-as -o %t.src.bc %S/Inputs/type-mapping-src.ll

; RUN: llvm-lto %t.dst.bc %t.src.bc -o=/dev/null



target triple = "x86_64-pc-windows-msvc18.0.0"



; @x in Src will be linked with this @x, causing SrcType in Src to be mapped

; to %DstType.

%DstType = type { i8 }

@x = global %DstType zeroinitializer



; The Src module will re-use our DINode for this type.

%CommonStruct = type { i32 }

@foo = internal global %CommonStruct zeroinitializer, !dbg !5



; That DINode will refer to this value, casted to %Tricky.1* (!11),

; which will then show up in Src's getIdentifiedStructTypes().

@templateValueParam = global i8 zeroinitializer



; Because of the names, we would try to map %Tricky.1 to %Tricky --

; mapping a Dst type to another Dst type! This would assert when

; getting a mapping from %DstType, which has previously used as

; a destination type. Since these types are not in the source module,

; there should be no attempt to create a mapping involving them;

; both types should be left as they are.

%Tricky = type opaque

%Tricky.1 = type { %DstType* }





; Mark %Tricky used.

@use = global %Tricky* zeroinitializer



!llvm.dbg.cu = !{!1}

!llvm.module.flags = !{!19}

!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, globals: !4)

!2 = !DIFile(filename: "a", directory: "/")

!3 = !{}

!4 = !{!5}

!5 = distinct !DIGlobalVariable(name: "foo", linkageName: "foo", scope: !1, file: !2, line: 5, type: !6, isLocal: false, isDefinition: true)

!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !2, line: 5, size: 8, elements: !7, identifier: ".?AUS@@")

!7 = !{!8}

!8 = !DIDerivedType(tag: DW_TAG_inheritance, scope: !6, baseType: !9)

!9 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Template<&x>", file: !2, line: 3, size: 8, elements: !3, templateParams: !10, identifier: ".?AU?$Template@$1?x@@3UX@@A@@")

!10 = !{!11}



!11 = !DITemplateValueParameter(type: !12, value: %Tricky.1* bitcast (i8* @templateValueParam to %Tricky.1*))



!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64)

!13 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "X", file: !2, line: 1, size: 8, elements: !3, identifier: ".?AUX@@")

!19 = !{i32 2, !"Debug Info Version", i32 3}