llvm/test/DebugInfo/Generic/lto-comp-dir.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

83 lines
3.6 KiB
LLVM

; REQUIRES: object-emission
; RUN: %llc_dwarf < %s -filetype=obj | llvm-dwarfdump -debug-dump=line - | FileCheck %s
; RUN: %llc_dwarf < %s -filetype=asm | FileCheck --check-prefix=ASM %s
; If multiple line tables are emitted, one per CU, those line tables can
; unambiguously rely on the comp_dir of their owning CU and use directory '0'
; to refer to it.
; CHECK: .debug_line contents:
; CHECK-NEXT: Line table prologue:
; CHECK-NOT: include_directories
; CHECK: file_names[ 1] 0 {{.*}} a.cpp
; CHECK-NOT: file_names
; CHECK: Line table prologue:
; CHECK-NOT: include_directories
; CHECK: file_names[ 1] 0 {{.*}} b.cpp
; CHECK-NOT: file_names
; However, if a single line table is emitted and shared between CUs, the
; comp_dir is ambiguous and relying on it would lead to different path
; interpretations depending on which CU lead to the table - so ensure that
; full paths are always emitted in this case, never comp_dir relative.
; ASM: .file 1 "/tmp/dbginfo/a{{[/\\]+}}a.cpp"
; ASM: .file 2 "/tmp/dbginfo/b{{[/\\]+}}b.cpp"
; Generated from the following source compiled to bitcode from within their
; respective directories (with debug info) and linked together with llvm-link
; a/a.cpp
; void func() {
; }
; b/b.cpp
; void func();
; int main() {
; func();
; }
; Function Attrs: nounwind uwtable
define void @_Z4funcv() #0 !dbg !4 {
entry:
ret void, !dbg !19
}
; Function Attrs: uwtable
define i32 @main() #1 !dbg !11 {
entry:
call void @_Z4funcv(), !dbg !20
ret i32 0, !dbg !21
}
attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.dbg.cu = !{!0, !8}
!llvm.module.flags = !{!16, !17}
!llvm.ident = !{!18, !18}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5.0 ", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!1 = !DIFile(filename: "a.cpp", directory: "/tmp/dbginfo/a")
!2 = !{}
!4 = distinct !DISubprogram(name: "func", linkageName: "_Z4funcv", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2)
!5 = !DIFile(filename: "a.cpp", directory: "/tmp/dbginfo/a")
!6 = !DISubroutineType(types: !7)
!7 = !{null}
!8 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5.0 ", isOptimized: false, emissionKind: FullDebug, file: !9, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!9 = !DIFile(filename: "b.cpp", directory: "/tmp/dbginfo/b")
!11 = distinct !DISubprogram(name: "main", line: 2, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !8, scopeLine: 2, file: !9, scope: !12, type: !13, variables: !2)
!12 = !DIFile(filename: "b.cpp", directory: "/tmp/dbginfo/b")
!13 = !DISubroutineType(types: !14)
!14 = !{!15}
!15 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!16 = !{i32 2, !"Dwarf Version", i32 4}
!17 = !{i32 1, !"Debug Info Version", i32 3}
!18 = !{!"clang version 3.5.0 "}
!19 = !DILocation(line: 2, scope: !4)
!20 = !DILocation(line: 3, scope: !11)
!21 = !DILocation(line: 4, scope: !11)