[clang] [llvm] [mlir] [llvm][DebugInfo][NFC] Abstract DICompileUnit::SourceLanguage to allow alternate DWARF SourceLanguage encoding (PR #162255)

[Adrian Prantl via llvm-commits]

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@@ -1866,11 +1866,13 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     // Ignore Record[0], which indicates whether this compile unit is
     // distinct.  It's always distinct.
     IsDistinct = true;
+
     auto *CU = DICompileUnit::getDistinct(
-        Context, Record[1], getMDOrNull(Record[2]), getMDString(Record[3]),
-        Record[4], getMDString(Record[5]), Record[6], getMDString(Record[7]),
-        Record[8], getMDOrNull(Record[9]), getMDOrNull(Record[10]),
-        getMDOrNull(Record[12]), getMDOrNull(Record[13]),
+        Context, DISourceLanguageName(Record[1]), getMDOrNull(Record[2]),
+        getMDString(Record[3]), Record[4], getMDString(Record[5]), Record[6],
+        getMDString(Record[7]), Record[8], getMDOrNull(Record[9]),
+        getMDOrNull(Record[10]), getMDOrNull(Record[12]),
+        getMDOrNull(Record[13]),
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adrian-prantl wrote:

Generally (assuming that the old and new enums are not compatible, we should add a .bc file to the tests with a compile unit in the old format to prove that we can upgrade it correctly.

https://github.com/llvm/llvm-project/pull/162255