llvm/test/DebugInfo/Generic/empty.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

32 lines
1.2 KiB
LLVM

; REQUIRES: object-emission
; RUN: %llc_dwarf < %s -filetype=obj | llvm-dwarfdump - | FileCheck %s
; RUN: %llc_dwarf -split-dwarf=Enable < %s -filetype=obj | llvm-dwarfdump - | FileCheck --check-prefix=FISSION %s
; darwin has a workaround for a linker bug so it always emits one line table entry
; XFAIL: darwin
; Expect no line table entry since there are no functions and file references in this compile unit
; CHECK: .debug_line contents:
; CHECK: Line table prologue:
; CHECK: total_length: 0x00000019
; CHECK-NOT: file_names[
; CHECK: .debug_pubnames contents:
; CHECK-NOT: Offset
; CHECK: .debug_pubtypes contents:
; CHECK-NOT: Offset
; Don't emit DW_AT_addr_base when there are no addresses.
; FISSION-NOT: DW_AT_GNU_addr_base [DW_FORM_sec_offset]
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!5}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.1 (trunk 143523)", isOptimized: true, emissionKind: FullDebug, file: !4, enums: !2, retainedTypes: !2, globals: !2)
!2 = !{}
!3 = !DIFile(filename: "empty.c", directory: "/home/nlewycky")
!4 = !DIFile(filename: "empty.c", directory: "/home/nlewycky")
!5 = !{i32 1, !"Debug Info Version", i32 3}