[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>
llvm-svn: 266446
diff --git a/llvm/test/DebugInfo/COFF/inlining-files.ll b/llvm/test/DebugInfo/COFF/inlining-files.ll
index a3b0d66..e5240cc 100644
--- a/llvm/test/DebugInfo/COFF/inlining-files.ll
+++ b/llvm/test/DebugInfo/COFF/inlining-files.ll
@@ -76,14 +76,13 @@
!llvm.module.flags = !{!12, !13, !14}
!llvm.ident = !{!15}
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, subprograms: !3, globals: !8)
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !8)
!1 = !DIFile(filename: "t.cpp", directory: "D:\5Csrc\5Cllvm\5Cbuild")
!2 = !{}
-!3 = !{!4, !7}
-!4 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 7, type: !5, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: true, variables: !2)
+!4 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 7, type: !5, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
!5 = !DISubroutineType(types: !6)
!6 = !{null}
-!7 = distinct !DISubprogram(name: "file_change", scope: !1, file: !1, line: 2, type: !5, isLocal: true, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, variables: !2)
+!7 = distinct !DISubprogram(name: "file_change", scope: !1, file: !1, line: 2, type: !5, isLocal: true, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
!8 = !{!9}
!9 = !DIGlobalVariable(name: "x", scope: !0, file: !1, line: 1, type: !10, isLocal: false, isDefinition: true, variable: i32* @x)
!10 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !11)