llvm/test/Linker/pr26037.ll
Adrian Prantl 4eeaa0da04 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266446 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-15 15:57:41 +00:00

60 lines
2.9 KiB
LLVM

; RUN: llvm-as %s -o %t.bc
; RUN: llvm-as %p/Inputs/pr26037.ll -o %t2.bc
; RUN: llvm-link -S -only-needed %t2.bc %t.bc | FileCheck %s
; CHECK: !DIImportedEntity({{.*}}, scope: ![[B:[0-9]+]], entity: ![[A:[0-9]+]]
; CHECK: ![[B]] = distinct !DISubprogram(name: "b"
; CHECK: ![[A]] = distinct !DISubprogram(name: "a"
; CHECK: !DIImportedEntity({{.*}}, scope: ![[LBC:[0-9]+]], entity: ![[LBD:[0-9]+]]
; CHECK: ![[LBC]] = distinct !DILexicalBlock(scope: ![[C:[0-9]+]]
; CHECK: ![[C]] = distinct !DISubprogram(name: "c"
; CHECK: ![[LBD]] = distinct !DILexicalBlock(scope: ![[D:[0-9]+]]
; CHECK: ![[D]] = distinct !DISubprogram(name: "d"
define void @_ZN1A1aEv() #0 !dbg !4 {
entry:
ret void, !dbg !14
}
define void @_ZN1A1bEv() #0 !dbg !8 {
entry:
ret void, !dbg !15
}
define void @_ZN1A1cEv() #0 !dbg !18 {
entry:
ret void, !dbg !21
}
define void @_ZN1A1dEv() #0 !dbg !20 {
entry:
ret void, !dbg !22
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!11, !12}
!llvm.ident = !{!13}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 256934) (llvm/trunk 256936)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, imports: !9)
!1 = !DIFile(filename: "a2.cc", directory: "")
!2 = !{}
!4 = distinct !DISubprogram(name: "a", linkageName: "_ZN1A1aEv", scope: !5, file: !1, line: 7, type: !6, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!5 = !DINamespace(name: "A", scope: null, file: !1, line: 1)
!6 = !DISubroutineType(types: !7)
!7 = !{null}
!8 = distinct !DISubprogram(name: "b", linkageName: "_ZN1A1bEv", scope: !5, file: !1, line: 8, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!9 = !{!10, !16}
!10 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !8, entity: !4, line: 8)
!11 = !{i32 2, !"Dwarf Version", i32 4}
!12 = !{i32 2, !"Debug Info Version", i32 3}
!13 = !{!"clang version 3.8.0 (trunk 256934) (llvm/trunk 256936)"}
!14 = !DILocation(line: 7, column: 12, scope: !4)
!15 = !DILocation(line: 8, column: 24, scope: !8)
!16 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !17, entity: !19, line: 8)
!17 = distinct !DILexicalBlock(scope: !18, file: !1, line: 9, column: 8)
!18 = distinct !DISubprogram(name: "c", linkageName: "_ZN1A1cEv", scope: !5, file: !1, line: 9, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!19 = distinct !DILexicalBlock(scope: !20, file: !1, line: 10, column: 8)
!20 = distinct !DISubprogram(name: "d", linkageName: "_ZN1A1dEv", scope: !5, file: !1, line: 10, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!21 = !DILocation(line: 9, column: 8, scope: !18)
!22 = !DILocation(line: 10, column: 8, scope: !20)