llvm/test/Linker/Inputs/mdlocation.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

24 lines
825 B
LLVM

define void @foo1() !dbg !0 {
ret void, !dbg !3
}
!named = !{!1, !2, !3, !4, !5}
!0 = distinct !DISubprogram(file: !7, scope: !7, line: 1, name: "foo", type: !9, unit: !6)
!1 = !DILocation(line: 3, column: 7, scope: !10)
!2 = !DILocation(line: 3, column: 7, scope: !10, inlinedAt: !1)
!3 = !DILocation(line: 3, column: 7, scope: !10, inlinedAt: !2)
; Test distinct nodes.
!4 = distinct !DILocation(line: 3, column: 7, scope: !10)
!5 = distinct !DILocation(line: 3, column: 7, scope: !10, inlinedAt: !4)
!llvm.dbg.cu = !{!6}
!6 = distinct !DICompileUnit(language: DW_LANG_C89, file: !7)
!7 = !DIFile(filename: "source.c", directory: "/dir")
!llvm.module.flags = !{!8}
!8 = !{i32 1, !"Debug Info Version", i32 3}
!9 = !DISubroutineType(types: !{})
!10 = distinct !DILexicalBlock(line: 3, column: 3, file: !7, scope: !0)