[llvm][DebugInfo] Adjust ModuleDebugInfoPrinter to versioned language names

[Michael137]

We shouldn't be calling getUnversionedName unconditionally because DWARFv6-enabled Clang will emit versioned language names that are versioned (i.e., sourceLanguageName...see new test case). We need to check hasVersionedName and pick the appropriate API based on that. Otherwise we assert in getUnversionedName.

[llvmbot]

@llvm/pr-subscribers-debuginfo

@llvm/pr-subscribers-llvm-analysis

Author: Michael Buch (Michael137)

Changes

We shouldn't be calling getUnversionedName unconditionally because DWARFv6-enabled Clang will emit versioned language names that are versioned (i.e., sourceLanguageName...see new test case). We need to check hasVersionedName and pick the appropriate API based on that. Otherwise we assert in getUnversionedName.

---

Full diff: https://github.com/llvm/llvm-project/pull/167293.diff

2 Files Affected:

• (modified) llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp (+12-6)
• (added) llvm/test/DebugInfo/Generic/debuginfofinder-cu-source-language-names.ll (+22)

diff --git a/llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp b/llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp
index f31d625eca14c..9d53c37461ba8 100644
--- a/llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp
+++ b/llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp
@@ -43,13 +43,19 @@ static void printModuleDebugInfo(raw_ostream &O, const Module *M,
   // filenames), so just print a few useful things.
   for (DICompileUnit *CU : Finder.compile_units()) {
     O << "Compile unit: ";
-    auto Lang =
-        dwarf::LanguageString(CU->getSourceLanguage().getUnversionedName());
-    if (!Lang.empty())
-      O << Lang;
+
+    DISourceLanguageName Lang = CU->getSourceLanguage();
+    auto LangStr =
+        Lang.hasVersionedName()
+            ? dwarf::SourceLanguageNameString(
+                  static_cast<llvm::dwarf::SourceLanguageName>(Lang.getName()))
+            : dwarf::LanguageString(Lang.getName());
+
+    if (!LangStr.empty())
+      O << LangStr;
     else
-      O << "unknown-language(" << CU->getSourceLanguage().getUnversionedName()
-        << ")";
+      O << "unknown-language(" << CU->getSourceLanguage().getName() << ")";
+
     printFile(O, CU->getFilename(), CU->getDirectory());
     O << '\n';
   }
diff --git a/llvm/test/DebugInfo/Generic/debuginfofinder-cu-source-language-names.ll b/llvm/test/DebugInfo/Generic/debuginfofinder-cu-source-language-names.ll
new file mode 100644
index 0000000000000..aafeb5ceb0db3
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/debuginfofinder-cu-source-language-names.ll
@@ -0,0 +1,22 @@
+; RUN: opt -passes='print<module-debuginfo>' -disable-output 2>&1 < %s \
+; RUN:   | FileCheck %s
+
+; CHECK: Compile unit: DW_LANG_C99 from /tmp/test1.c
+; CHECK: Compile unit: DW_LNAME_C from /tmp/test2.c
+; CHECK: Compile unit: unknown-language(0) from /tmp/test3.c
+
+!llvm.dbg.cu = !{!0, !6, !10}
+!llvm.module.flags = !{!8, !9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!1 = !DIFile(filename: "test1.c", directory: "/tmp")
+!2 = !{}
+!3 = !DIFile(filename: "test1.c", directory: "/tmp")
+!4 = !DISubroutineType(types: !7)
+!5 = !{null}
+!6 = distinct !DICompileUnit(sourceLanguageName: DW_LNAME_C, producer: "clang", isOptimized: false, emissionKind: FullDebug, file: !7, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!7 = !DIFile(filename: "test2.c", directory: "/tmp")
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 1, !"Debug Info Version", i32 3}
+!10 = distinct !DICompileUnit(sourceLanguageName: 0, producer: "clang", isOptimized: false, emissionKind: FullDebug, file: !11, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!11 = !DIFile(filename: "test3.c", directory: "/tmp")