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/Bitcode/debug-loc-again.ll b/llvm/test/Bitcode/debug-loc-again.ll
index a3923c85f88..adf74a07ebe 100644
--- a/llvm/test/Bitcode/debug-loc-again.ll
+++ b/llvm/test/Bitcode/debug-loc-again.ll
@@ -31,6 +31,6 @@ entry:
 !0 = !{i32 2, !"Debug Info Version", i32 3}
 !1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !DIFile(filename: "f", directory: "/d"),
                              subprograms: !{!2})
-!2 = !DISubprogram(name: "foo")
+!2 = distinct !DISubprogram(name: "foo")
 !3 = !DILocation(line: 1, scope: !2)
 !4 = !DILocation(line: 2, scope: !2)