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

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Merged
merged 3 commits into from
Oct 10, 2025
+74 −27
Merged

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

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1ddc997
[llvm][DebugInfo] Emit DW_AT_lanugage_name
Michael137 Oct 7, 2025
2f5a3a7
fixup! fix CodeView SourceLanguage mappings
Michael137 Oct 10, 2025
34d4fa2
fixup! simplify MapDWARFLanguageToCVLang
Michael137 Oct 10, 2025
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53 changes: 28 additions & 25 deletions llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -569,40 +569,30 @@ void CodeViewDebug::emitCodeViewMagicVersion() {
OS.emitInt32(COFF::DEBUG_SECTION_MAGIC);
}

static SourceLanguage MapDWLangToCVLang(unsigned DWLang) {
switch (DWLang) {
case dwarf::DW_LANG_C:
case dwarf::DW_LANG_C89:
case dwarf::DW_LANG_C99:
case dwarf::DW_LANG_C11:
static SourceLanguage
MapDWARFLanguageToCVLang(dwarf::SourceLanguageName DWLName) {
switch (DWLName) {
case dwarf::DW_LNAME_C:
return SourceLanguage::C;
case dwarf::DW_LANG_C_plus_plus:
case dwarf::DW_LANG_C_plus_plus_03:
case dwarf::DW_LANG_C_plus_plus_11:
case dwarf::DW_LANG_C_plus_plus_14:
case dwarf::DW_LNAME_C_plus_plus:
return SourceLanguage::Cpp;
case dwarf::DW_LANG_Fortran77:
case dwarf::DW_LANG_Fortran90:
case dwarf::DW_LANG_Fortran95:
case dwarf::DW_LANG_Fortran03:
case dwarf::DW_LANG_Fortran08:
case dwarf::DW_LNAME_Fortran:
return SourceLanguage::Fortran;
case dwarf::DW_LANG_Pascal83:
case dwarf::DW_LNAME_Pascal:
return SourceLanguage::Pascal;
case dwarf::DW_LANG_Cobol74:
case dwarf::DW_LANG_Cobol85:
case dwarf::DW_LNAME_Cobol:
return SourceLanguage::Cobol;
case dwarf::DW_LANG_Java:
case dwarf::DW_LNAME_Java:
return SourceLanguage::Java;
case dwarf::DW_LANG_D:
case dwarf::DW_LNAME_D:
return SourceLanguage::D;
case dwarf::DW_LANG_Swift:
case dwarf::DW_LNAME_Swift:
return SourceLanguage::Swift;
case dwarf::DW_LANG_Rust:
case dwarf::DW_LNAME_Rust:
return SourceLanguage::Rust;
case dwarf::DW_LANG_ObjC:
case dwarf::DW_LNAME_ObjC:
return SourceLanguage::ObjC;
case dwarf::DW_LANG_ObjC_plus_plus:
case dwarf::DW_LNAME_ObjC_plus_plus:
return SourceLanguage::ObjCpp;
default:
// There's no CodeView representation for this language, and CV doesn't
Expand All @@ -612,6 +602,14 @@ static SourceLanguage MapDWLangToCVLang(unsigned DWLang) {
}
}

static SourceLanguage MapDWARFLanguageToCVLang(dwarf::SourceLanguage DWLang) {
auto MaybeLName = dwarf::toDW_LNAME(DWLang);
if (!MaybeLName)
return MapDWARFLanguageToCVLang(static_cast<dwarf::SourceLanguageName>(0));

return MapDWARFLanguageToCVLang(MaybeLName->first);
}

void CodeViewDebug::beginModule(Module *M) {
// If COFF debug section is not available, skip any debug info related stuff.
if (!Asm->getObjFileLowering().getCOFFDebugSymbolsSection()) {
Expand All @@ -633,8 +631,13 @@ void CodeViewDebug::beginModule(Module *M) {
Node = *CUs->operands().begin();
}
const auto *CU = cast<DICompileUnit>(Node);
DISourceLanguageName Lang = CU->getSourceLanguage();
CurrentSourceLanguage =
MapDWLangToCVLang(CU->getSourceLanguage().getUnversionedName());
Lang.hasVersionedName()
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Without this adjustment, the new compileunit-source-language-name.ll‎ test would assert in getUnversionedName on Windows bots (caught by pre-merge CI).

? MapDWARFLanguageToCVLang(
static_cast<dwarf::SourceLanguageName>(Lang.getName()))
: MapDWARFLanguageToCVLang(
static_cast<dwarf::SourceLanguage>(Lang.getName()));
if (!M->getCodeViewFlag() ||
CU->getEmissionKind() == DICompileUnit::NoDebug) {
Asm = nullptr;
Expand Down
8 changes: 6 additions & 2 deletions llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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();
Expand Down
20 changes: 20 additions & 0 deletions llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
; 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

!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}
20 changes: 20 additions & 0 deletions llvm/test/DebugInfo/Generic/compileunit-source-language.ll
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Original file line number Diff line number Diff line change
@@ -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}