[llvm] [llvm][DebugInfo] Support versioned source language names in DwarfUnit (PR #162625)

[Michael Buch via llvm-commits]

https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/162625

>From 6517236366a2b6a489b420989cf969d09e497eb8 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Thu, 9 Oct 2025 11:00:54 +0100
Subject: [PATCH 1/2] [llvm][DebugInfo] Support versioned source language names
 in DwarfUnit

---
 llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp             | 11 +++++++++--
 .../Generic/compileunit-source-language-name.ll       |  9 +++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index aa078f3f81d49..b58536f89ccb5 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -705,8 +705,15 @@ void DwarfUnit::addType(DIE &Entity, const DIType *Ty,
 }
 
 llvm::dwarf::SourceLanguage DwarfUnit::getSourceLanguage() const {
-  return static_cast<llvm::dwarf::SourceLanguage>(
-      getLanguage().getUnversionedName());
+  const auto &Lang = getLanguage();
+
+  if (!Lang.hasVersionedName())
+    return static_cast<llvm::dwarf::SourceLanguage>(Lang.getName());
+
+  return llvm::dwarf::toDW_LANG(
+             static_cast<llvm::dwarf::SourceLanguageName>(Lang.getName()),
+             Lang.getVersion())
+      .value_or(llvm::dwarf::DW_LANG_hi_user);
 }
 
 std::string DwarfUnit::getParentContextString(const DIScope *Context) const {
diff --git a/llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll b/llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll
index 94e32ab8c65b2..edb4e669d4631 100644
--- a/llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll
+++ b/llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll
@@ -7,6 +7,11 @@ target triple = "arm64-apple-macosx"
 
 @x = global i32 0, align 4, !dbg !0
 
+; Function Attrs: mustprogress noinline nounwind optnone ssp uwtable(sync)
+define void @_Z4funcv() !dbg !8 {
+  ret void, !dbg !11
+}
+
 !llvm.dbg.cu = !{!2}
 !llvm.module.flags = !{!6, !7}
 
@@ -18,3 +23,7 @@ target triple = "arm64-apple-macosx"
 !5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !6 = !{i32 7, !"Dwarf Version", i32 5}
 !7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = distinct !DISubprogram(name: "func", linkageName: "_Z4funcv", scope: !3, file: !3, line: 2, type: !9, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !DILocation(line: 2, column: 14, scope: !8)

>From fe47abb2311ab3f40527bc6e332c2662ed0b598a Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Sat, 11 Oct 2025 09:22:49 +0100
Subject: [PATCH 2/2] fixup! add FIXME

---
 llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index b58536f89ccb5..e40fb768027b8 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -704,6 +704,7 @@ void DwarfUnit::addType(DIE &Entity, const DIType *Ty,
   addDIEEntry(Entity, Attribute, DIEEntry(*getOrCreateTypeDIE(Ty)));
 }
 
+// FIXME: change callsites to use the new DW_LNAME_ language codes.
 llvm::dwarf::SourceLanguage DwarfUnit::getSourceLanguage() const {
   const auto &Lang = getLanguage();