llvm/test/CodeGen/X86/null-streamer.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

28 lines
1.1 KiB
LLVM

; Check the MCNullStreamer operates correctly, at least on a minimal test case.
;
; RUN: llc -filetype=null -o %t -march=x86 %s
; RUN: llc -filetype=null -o %t -mtriple=i686-cygwin %s
define void @f0() {
ret void
}
define void @f1() {
ret void
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!11, !13}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: " ", isOptimized: true, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !9, imports: !2)
!1 = !DIFile(filename: "file.c", directory: "")
!2 = !{}
!4 = distinct !DISubprogram(name: "", line: 2, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 2, file: !1, scope: !1, type: !6, variables: !2)
!6 = !DISubroutineType(types: !7)
!7 = !{!8}
!8 = !DIBasicType(tag: DW_TAG_base_type, size: 32, align: 32, encoding: DW_ATE_signed)
!9 = !{!10}
!10 = !DIGlobalVariable(name: "i", linkageName: "_ZL1i", line: 1, isLocal: true, isDefinition: true, scope: null, file: !1, type: !8)
!11 = !{i32 2, !"Dwarf Version", i32 3}
!13 = !{i32 1, !"Debug Info Version", i32 3}