[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/Transforms/LoopVectorize/conditional-assignment.ll b/llvm/test/Transforms/LoopVectorize/conditional-assignment.ll
index e1f0add..a60e8a2 100644
--- a/llvm/test/Transforms/LoopVectorize/conditional-assignment.ll
+++ b/llvm/test/Transforms/LoopVectorize/conditional-assignment.ll
@@ -36,11 +36,10 @@
!llvm.module.flags = !{!7, !8}
!llvm.ident = !{!9}
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.6.0", isOptimized: true, emissionKind: LineTablesOnly, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.6.0", isOptimized: true, emissionKind: LineTablesOnly, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!1 = !DIFile(filename: "source.c", directory: ".")
!2 = !{}
-!3 = !{!4}
-!4 = distinct !DISubprogram(name: "conditional_store", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2)
+!4 = distinct !DISubprogram(name: "conditional_store", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2)
!5 = !DIFile(filename: "source.c", directory: ".")
!6 = !DISubroutineType(types: !2)
!7 = !{i32 2, !"Dwarf Version", i32 2}