llvm/test/DebugInfo/Generic/debuginfofinder-forward-declaration.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

43 lines
1.8 KiB
LLVM

; RUN: opt -analyze -module-debuginfo < %s | FileCheck %s
; This module is generated from the following c-code:
;
; > union X;
; >
; > struct Y {
; > union X *x;
; > };
; >
; > struct Y y;
; CHECK: Type: Y from /tmp/minimal.c:3 DW_TAG_structure_type
; CHECK: Type: x from /tmp/minimal.c:4 DW_TAG_member
; CHECK: Type: DW_TAG_pointer_type
; CHECK: Type: X from /tmp/minimal.c:1 DW_TAG_structure_type
%struct.Y = type { %struct.X* }
%struct.X = type opaque
@y = common global %struct.Y zeroinitializer, align 8
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!10, !11}
!llvm.ident = !{!12}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.7.0 (http://llvm.org/git/clang.git 247b30a043eb8f39ea3708e7e995089da0a6b00f) (http://llvm.org/git/llvm.git 6ecc7365a89c771fd229bdd9ffcc178684ea1aa5)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !3, imports: !2)
!1 = !DIFile(filename: "minimal.c", directory: "/tmp")
!2 = !{}
!3 = !{!4}
!4 = !DIGlobalVariable(name: "y", scope: !0, file: !1, line: 7, type: !5, isLocal: false, isDefinition: true, variable: %struct.Y* @y)
!5 = !DICompositeType(tag: DW_TAG_structure_type, name: "Y", file: !1, line: 3, size: 64, align: 64, elements: !6)
!6 = !{!7}
!7 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !5, file: !1, line: 4, baseType: !8, size: 64, align: 64)
!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, align: 64)
!9 = !DICompositeType(tag: DW_TAG_structure_type, name: "X", file: !1, line: 1, flags: DIFlagFwdDecl)
!10 = !{i32 2, !"Dwarf Version", i32 4}
!11 = !{i32 2, !"Debug Info Version", i32 3}
!12 = !{!"clang version 3.7.0 (http://llvm.org/git/clang.git 247b30a043eb8f39ea3708e7e995089da0a6b00f) (http://llvm.org/git/llvm.git 6ecc7365a89c771fd229bdd9ffcc178684ea1aa5)"}