llvm/test/DebugInfo/X86/debug_frame.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

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LLVM

; RUN: llc %s -mtriple=i686-pc-linux-gnu -o - | FileCheck %s
; Test that we produce a .debug_frame, not an .eh_frame
; CHECK: .cfi_sections .debug_frame
define void @f() nounwind !dbg !0 {
entry:
ret void
}
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!7}
!5 = !{!0}
!0 = distinct !DISubprogram(name: "f", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !2, scopeLine: 1, file: !6, scope: !1, type: !3)
!1 = !DIFile(filename: "/home/espindola/llvm/test.c", directory: "/home/espindola/llvm/build")
!2 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.0 ()", isOptimized: true, emissionKind: FullDebug, file: !6, enums: !{}, retainedTypes: !{})
!3 = !DISubroutineType(types: !4)
!4 = !{null}
!6 = !DIFile(filename: "/home/espindola/llvm/test.c", directory: "/home/espindola/llvm/build")
!7 = !{i32 1, !"Debug Info Version", i32 3}