[llvm][DebugInfo] Support versioned source language names in DwarfUnit

[Michael137]

Depends on:

• [llvm][DebugInfo] Add support for emitting DW_AT_language_name #162621

Now we can start emitting DW_AT_language_name, make sure DwarfUnit::getSourceLanguage is equipped to handle this. Otherwise the new test-case would assert.

[llvmbot]

@llvm/pr-subscribers-debuginfo

Author: Michael Buch (Michael137)

Changes

Depends on:

• [llvm][DebugInfo] Add support for emitting DW_AT_language_name #162621

Now we can start emitting DW_AT_language_name, make sure DwarfUnit::getSourceLanguage is equipped to handle this. Otherwise the new test-case would assert.

---

Full diff: https://github.com/llvm/llvm-project/pull/162625.diff

4 Files Affected:

• (modified) llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (+6-2)
• (modified) llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (+9-2)
• (added) llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll (+29)
• (added) llvm/test/DebugInfo/Generic/compileunit-source-language.ll (+20)

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d751a7f9f01ef..433877f3a8b98 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1039,8 +1039,12 @@ void DwarfDebug::finishUnitAttributes(const DICompileUnit *DIUnit,
   } else
     NewCU.addString(Die, dwarf::DW_AT_producer, Producer);
 
-  NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
-                DIUnit->getSourceLanguage().getUnversionedName());
+  if (auto Lang = DIUnit->getSourceLanguage(); Lang.hasVersionedName())
+    NewCU.addUInt(Die, dwarf::DW_AT_language_name, dwarf::DW_FORM_data2,
+                  Lang.getName());
+  else
+    NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
+                  Lang.getName());
 
   NewCU.addString(Die, dwarf::DW_AT_name, FN);
   StringRef SysRoot = DIUnit->getSysRoot();
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
new file mode 100644
index 0000000000000..edb4e669d4631
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll
@@ -0,0 +1,29 @@
+; RUN: %llc_dwarf -filetype=obj -O0 < %s | llvm-dwarfdump -debug-info - | FileCheck %s --implicit-check-not "DW_AT_language"
+
+; CHECK: DW_AT_language_name (DW_LNAME_ObjC_plus_plus)
+
+source_filename = "cu.cpp"
+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}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(sourceLanguageName: DW_LNAME_ObjC_plus_plus, file: !3, producer: "handwritten", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: Apple, sysroot: "/")
+!3 = !DIFile(filename: "cu.cpp", directory: "/tmp")
+!4 = !{!0}
+!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)
diff --git a/llvm/test/DebugInfo/Generic/compileunit-source-language.ll b/llvm/test/DebugInfo/Generic/compileunit-source-language.ll
new file mode 100644
index 0000000000000..0d0da4fa11d64
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/compileunit-source-language.ll
@@ -0,0 +1,20 @@
+; RUN: %llc_dwarf -filetype=obj -O0 < %s | llvm-dwarfdump -debug-info - | FileCheck %s --implicit-check-not "DW_AT_language_name"
+
+; CHECK: DW_AT_language (DW_LANG_C)
+
+source_filename = "cu.cpp"
+target triple = "arm64-apple-macosx"
+
+@x = global i32 0, align 4, !dbg !0
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!6, !7}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "handwritten", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: Apple, sysroot: "/")
+!3 = !DIFile(filename: "cu.cpp", directory: "/tmp")
+!4 = !{!0}
+!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}