DI: Require subprogram definitions to be distinct

As a follow-up to r246098, require `DISubprogram` definitions
(`isDefinition: true`) to be 'distinct'.  Specifically, add an assembler
check, a verifier check, and bitcode upgrading logic to combat testcase
bitrot after the `DIBuilder` change.

While working on the testcases, I realized that
test/Linker/subprogram-linkonce-weak-odr.ll isn't relevant anymore.  Its
purpose was to check for a corner case in PR22792 where two subprogram
definitions match exactly and share the same metadata node.  The new
verifier check, requiring that subprogram definitions are 'distinct',
precludes that possibility.

I updated almost all the IR with the following script:

    git grep -l -E -e '= !DISubprogram\(.* isDefinition: true' |
    grep -v test/Bitcode |
    xargs sed -i '' -e 's/= \(!DISubprogram(.*, isDefinition: true\)/= distinct \1/'

Likely some variant of would work for out-of-tree testcases.

llvm-svn: 246327

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/test/Verifier/llvm.dbg.value-expression.ll b/llvm/test/Verifier/llvm.dbg.value-expression.ll
index 3999d4da073..dd3c29f9107 100644
--- a/llvm/test/Verifier/llvm.dbg.value-expression.ll
+++ b/llvm/test/Verifier/llvm.dbg.value-expression.ll
@@ -14,4 +14,4 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
 
 !llvm.module.flags = !{!0}
 !0 = !{i32 2, !"Debug Info Version", i32 3}
-!1 = !DISubprogram()
+!1 = distinct !DISubprogram()