DI: Disallow uniquable DICompileUnits

Since r241097, `DIBuilder` has only created distinct `DICompileUnit`s.
The backend is liable to start relying on that (if it hasn't already),
so make uniquable `DICompileUnit`s illegal and automatically upgrade old
bitcode.  This is a nice cleanup, since we can remove an unnecessary
`DenseSet` (and the associated uniquing info) from `LLVMContextImpl`.

Almost all the testcases were updated with this script:

    git grep -e '= !DICompileUnit' -l -- test |
    grep -v test/Bitcode |
    xargs sed -i '' -e 's,= !DICompileUnit,= distinct !DICompileUnit,'

I imagine something similar should work for out-of-tree testcases.

llvm-svn: 243885

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/test/DebugInfo/X86/debug_frame.ll b/llvm/test/DebugInfo/X86/debug_frame.ll
index 48ce554f011..c6b0e11054e 100644
--- a/llvm/test/DebugInfo/X86/debug_frame.ll
+++ b/llvm/test/DebugInfo/X86/debug_frame.ll
@@ -15,7 +15,7 @@ entry:
 
 !0 = !DISubprogram(name: "f", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1, file: !6, scope: !1, type: !3, function: void ()* @f)
 !1 = !DIFile(filename: "/home/espindola/llvm/test.c", directory: "/home/espindola/llvm/build")
-!2 = !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.0 ()", isOptimized: true, emissionKind: 0, file: !6, enums: !{}, retainedTypes: !{}, subprograms: !5)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.0 ()", isOptimized: true, emissionKind: 0, file: !6, enums: !{}, retainedTypes: !{}, subprograms: !5)
 !3 = !DISubroutineType(types: !4)
 !4 = !{null}
 !6 = !DIFile(filename: "/home/espindola/llvm/test.c", directory: "/home/espindola/llvm/build")