[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/Generic/inline-debug-info.ll b/llvm/test/DebugInfo/Generic/inline-debug-info.ll
index 8822d5f..343680e 100644
--- a/llvm/test/DebugInfo/Generic/inline-debug-info.ll
+++ b/llvm/test/DebugInfo/Generic/inline-debug-info.ll
@@ -140,17 +140,16 @@
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!31}
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.3 ", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.3 ", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!1 = !DIFile(filename: "<unknown>", directory: "")
!2 = !{}
-!3 = !{!4, !10}
-!4 = distinct !DISubprogram(name: "test", linkageName: "_Z4testi", line: 4, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 4, file: !5, scope: !6, type: !7, variables: !2)
+!4 = distinct !DISubprogram(name: "test", linkageName: "_Z4testi", line: 4, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 4, file: !5, scope: !6, type: !7, variables: !2)
!5 = !DIFile(filename: "test.cpp", directory: "")
!6 = !DIFile(filename: "test.cpp", directory: "")
!7 = !DISubroutineType(types: !8)
!8 = !{!9, !9}
!9 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
-!10 = distinct !DISubprogram(name: "test2", linkageName: "_Z5test2v", line: 11, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 11, file: !5, scope: !6, type: !11, variables: !2)
+!10 = distinct !DISubprogram(name: "test2", linkageName: "_Z5test2v", line: 11, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 11, file: !5, scope: !6, type: !11, variables: !2)
!11 = !DISubroutineType(types: !12)
!12 = !{!9}
!13 = !DILocalVariable(name: "k", line: 4, arg: 1, scope: !4, file: !6, type: !9)