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[llvm-dwarfdump] Support for DW_AT_language_name and DW_AT_language_version #162449

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Oct 10, 2025
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[llvm-dwarfdump] Support for DW_AT_language_name and DW_AT_language_version #162449

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2 changes: 2 additions & 0 deletions llvm/lib/BinaryFormat/Dwarf.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -893,6 +893,8 @@ StringRef llvm::dwarf::AttributeValueString(uint16_t Attr, unsigned Val) {
return DefaultedMemberString(Val);
case DW_AT_APPLE_enum_kind:
return EnumKindString(Val);
case DW_AT_language_name:
return SourceLanguageNameString(static_cast<SourceLanguageName>(Val));
}

return StringRef();
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3 changes: 2 additions & 1 deletion llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
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Expand Up @@ -149,7 +149,8 @@ static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
if (!Name.empty())
WithColor(OS, Color) << Name;
else if (Attr == DW_AT_decl_line || Attr == DW_AT_decl_column ||
Attr == DW_AT_call_line || Attr == DW_AT_call_column) {
Attr == DW_AT_call_line || Attr == DW_AT_call_column ||
Attr == DW_AT_language_version) {
if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
OS << *Val;
else
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35 changes: 35 additions & 0 deletions llvm/test/tools/llvm-dwarfdump/X86/DW_AT_language_name.s
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@@ -0,0 +1,35 @@
# Demonstrate dumping DW_AT_language_name.
# RUN: llvm-mc -triple=x86_64--linux -filetype=obj < %s | \
# RUN: llvm-dwarfdump -v - | FileCheck %s

# CHECK: .debug_abbrev contents:
# CHECK: DW_AT_language_name DW_FORM_data2
# CHECK: DW_AT_language_name DW_FORM_data2
# CHECK: .debug_info contents:
# CHECK: DW_AT_language_name [DW_FORM_data2] (DW_LNAME_C)
# CHECK: DW_AT_language_name [DW_FORM_data2] (0x0000)

.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_no
.ascii "\220\001" # DW_AT_language_name
.byte 5 # DW_FORM_data2
.ascii "\220\001" # DW_AT_language_name
.byte 5 # DW_FORM_data2
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)

.section .debug_info,"",@progbits
.long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
.Ldebug_info_start0:
.short 5 # DWARF version number
.byte 1 # Unit type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 1 # Abbrev [1] DW_TAG_compile_unit
.short 3 # DW_AT_language_name
.short 0 # DW_AT_language_name
.byte 0
.Ldebug_info_end0:
35 changes: 35 additions & 0 deletions llvm/test/tools/llvm-dwarfdump/X86/DW_AT_language_version.s
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@@ -0,0 +1,35 @@
# Demonstrate dumping DW_AT_language_version.
# RUN: llvm-mc -triple=x86_64--linux -filetype=obj < %s | \
# RUN: llvm-dwarfdump -v - | FileCheck %s

# CHECK: .debug_abbrev contents:
# CHECK: DW_AT_language_version DW_FORM_data4
# CHECK: DW_AT_language_version DW_FORM_data2
# CHECK: .debug_info contents:
# CHECK: DW_AT_language_version [DW_FORM_data4] (201402)
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Should dwarfdump also translate this into the human-readable version?
i.e.:

dwarfdump: DW_AT_language_version (C++17)
dwarfdump -v: DW_AT_language_version (201402)

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That would be a neat addition. We'd have to detect the fact that there is a DW_AT_language_name present (I don't think the standard mandates that both attributes be present). Although it would be weird to have a version without a name. Might be worth asking the committee to clarify.

Either way, I'll do it as a follow-up. For now I wanted to just get the minimal dwarfdump support for testing these attributes

# CHECK: DW_AT_language_version [DW_FORM_data2] (0)

.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_no
.ascii "\221\001" # DW_AT_language_version
.byte 6 # DW_FORM_data4
.ascii "\221\001" # DW_AT_language_version
.byte 5 # DW_FORM_data2
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)

.section .debug_info,"",@progbits
.long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
.Ldebug_info_start0:
.short 5 # DWARF version number
.byte 1 # Unit type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 1 # Abbrev [1] DW_TAG_compile_unit
.long 201402 # DW_AT_language_version
.short 0 # DW_AT_language_version
.byte 0
.Ldebug_info_end0: