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-info-block-captured-self.ll b/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll
index c5cb0563c45..0991251bee0 100644
--- a/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll
+++ b/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll
@@ -80,7 +80,7 @@ define internal void @"__24-[Main initWithContext:]_block_invoke_2"(i8* %.block_
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!108}
-!0 = !DICompileUnit(language: DW_LANG_ObjC, producer: "clang version 3.3 ", isOptimized: false, runtimeVersion: 2, emissionKind: 0, file: !107, enums: !2, retainedTypes: !4, subprograms: !23, globals: !15, imports:  !15)
+!0 = distinct !DICompileUnit(language: DW_LANG_ObjC, producer: "clang version 3.3 ", isOptimized: false, runtimeVersion: 2, emissionKind: 0, file: !107, enums: !2, retainedTypes: !4, subprograms: !23, globals: !15, imports:  !15)
 !1 = !DIFile(filename: "llvm/tools/clang/test/CodeGenObjC/debug-info-block-captured-self.m", directory: "")
 !2 = !{!3}
 !3 = !DICompositeType(tag: DW_TAG_enumeration_type, line: 20, size: 32, align: 32, file: !107, elements: !4)