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/Linker/Inputs/subprogram-linkonce-weak.ll b/llvm/test/Linker/Inputs/subprogram-linkonce-weak.ll
index f5399e244a9..85227d3ac29 100644
--- a/llvm/test/Linker/Inputs/subprogram-linkonce-weak.ll
+++ b/llvm/test/Linker/Inputs/subprogram-linkonce-weak.ll
@@ -10,7 +10,7 @@ declare i32 @fastadd(i32, i32)
 !0 = !{i32 2, !"Debug Info Version", i32 3}
 
 !llvm.dbg.cu = !{!1}
-!1 = !DICompileUnit(language: DW_LANG_C99, file: !2, subprograms: !{!3}, emissionKind: 1)
+!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, subprograms: !{!3}, emissionKind: 1)
 !2 = !DIFile(filename: "foo.c", directory: "/path/to/dir")
 !3 = !DISubprogram(file: !2, scope: !2, line: 51, name: "foo", function: i32 (i32, i32)* @foo, type: !4)
 !4 = !DISubroutineType(types: !{})