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[llvm][dwarfdump] Pretty-print DW_AT_language_version #164222

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merged 5 commits into from
Oct 21, 2025
Merged

[llvm][dwarfdump] Pretty-print DW_AT_language_version #164222

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eaeeeac
[llvm][dwarfdump] Pretty-print DW_AT_language_version in non-verbose …
Michael137 Oct 20, 2025
662b7e6
fixup! fix test
Michael137 Oct 20, 2025
9deb8f4
fixup! print prettfied name in verbose mode too
Michael137 Oct 20, 2025
16ee162
fixup! no const local
Michael137 Oct 21, 2025
20e0411
fixup! add test explanation; add test-case for invalid DW_AT_language…
Michael137 Oct 21, 2025
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49 changes: 44 additions & 5 deletions llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -107,6 +107,28 @@ static DWARFDie resolveReferencedType(DWARFDie D, DWARFFormValue F) {
return D.getAttributeValueAsReferencedDie(F).resolveTypeUnitReference();
}

static llvm::StringRef
prettyLanguageVersionString(const DWARFAttribute &AttrValue,
const DWARFDie &Die) {
if (AttrValue.Attr != DW_AT_language_version)
return {};

auto NameForm = Die.find(DW_AT_language_name);
if (!NameForm)
return {};

auto LName = NameForm->getAsUnsignedConstant();
if (!LName)
return {};

auto LVersion = AttrValue.Value.getAsUnsignedConstant();
if (!LVersion)
return {};

return llvm::dwarf::LanguageDescription(
static_cast<SourceLanguageName>(*LName), *LVersion);
}

static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
const DWARFAttribute &AttrValue, unsigned Indent,
DIDumpOptions DumpOpts) {
Expand Down Expand Up @@ -146,15 +168,28 @@ static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
} else if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
Name = AttributeValueString(Attr, *Val);

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_language_version) {
auto DumpUnsignedConstant = [&OS,
&DumpOpts](const DWARFFormValue &FormValue) {
if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
OS << *Val;
else
FormValue.dump(OS, DumpOpts);
};

llvm::StringRef PrettyVersionName =
prettyLanguageVersionString(AttrValue, Die);
const bool ShouldDumpRawLanguageVersion =
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@dwblaikie dwblaikie Oct 20, 2025

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We don't usually use const on locals - ends up feeling pretty inconsistent & then confusing when it is used (eg: why is it on this local, but not on PrettyVersionName, or DumpUnsignedConstant above?

Attr == DW_AT_language_version &&
(DumpOpts.Verbose || PrettyVersionName.empty());

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) {
DumpUnsignedConstant(FormValue);
} else if (Attr == DW_AT_language_version) {
if (ShouldDumpRawLanguageVersion)
DumpUnsignedConstant(FormValue);
} else if (Attr == DW_AT_low_pc &&
(FormValue.getAsAddress() ==
dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
Expand Down Expand Up @@ -226,6 +261,10 @@ static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
DumpOpts.RecoverableErrorHandler(createStringError(
errc::invalid_argument, "decoding address ranges: %s",
toString(RangesOrError.takeError()).c_str()));
} else if (Attr == DW_AT_language_version) {
if (!PrettyVersionName.empty())
WithColor(OS, Color) << (ShouldDumpRawLanguageVersion ? " " : "")
<< PrettyVersionName;
}

OS << ")\n";
Expand Down
10 changes: 5 additions & 5 deletions llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll
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Original file line number Diff line number Diff line change
@@ -1,11 +1,11 @@
; AIX doesn't have support for DWARF 6 DW_AT_language_name
; XFAIL: target={{.*}}-zos{{.*}}, target={{.*}}-aix{{.*}}
; RUN: %llc_dwarf -filetype=obj -O0 < %s | llvm-dwarfdump -debug-info - | FileCheck %s --implicit-check-not "DW_AT_language"
; RUN: %llc_dwarf -filetype=obj -O0 < %s | llvm-dwarfdump -debug-info -v - | FileCheck %s --implicit-check-not "DW_AT_language"

; CHECK: DW_AT_language_name (DW_LNAME_ObjC_plus_plus)
; CHECK: DW_AT_language_name (DW_LNAME_C_plus_plus)
; CHECK: DW_AT_language_version (201100)
; CHECK: DW_AT_language_name (DW_LNAME_Rust)
; CHECK: DW_AT_language_name [DW_FORM_data2] (DW_LNAME_ObjC_plus_plus)
; CHECK: DW_AT_language_name [DW_FORM_data2] (DW_LNAME_C_plus_plus)
; CHECK: DW_AT_language_version [DW_FORM_data4] (201100 C++11)
; CHECK: DW_AT_language_name [DW_FORM_data2] (DW_LNAME_Rust)
; CHECK-NOT: DW_AT_language_version

@x = global i32 0, align 4, !dbg !0
Expand Down
37 changes: 37 additions & 0 deletions llvm/test/tools/llvm-dwarfdump/X86/DW_AT_language_version-pretty.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,37 @@
# Demonstrate dumping DW_AT_language_version in human-readable form.
# RUN: llvm-mc -triple=x86_64--linux -filetype=obj -o %t.o < %s
# RUN: llvm-dwarfdump %t.o -v | FileCheck %s --check-prefix=VERBOSE
# RUN: llvm-dwarfdump %t.o | FileCheck %s --check-prefix=NO-VERBOSE

# VERBOSE: .debug_info contents:
# VERBOSE: DW_AT_language_name [DW_FORM_data2] (DW_LNAME_C)
# VERBOSE: DW_AT_language_version [DW_FORM_data4] (201112 C11)

# NO-VERBOSE: .debug_info contents:
# NO-VERBOSE: DW_AT_language_name (DW_LNAME_C)
# NO-VERBOSE: DW_AT_language_version (C11)

.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 "\221\001" # DW_AT_language_version
.byte 6 # DW_FORM_data4
.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
.long 201112 # DW_AT_language_version
.byte 0
.Ldebug_info_end0:
21 changes: 13 additions & 8 deletions llvm/test/tools/llvm-dwarfdump/X86/DW_AT_language_version.s
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Original file line number Diff line number Diff line change
@@ -1,13 +1,18 @@
# Demonstrate dumping DW_AT_language_version.
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@dwblaikie dwblaikie Oct 20, 2025

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This is the case where we don't recognize the language or version code? perhaps the test file name and/or header comment could clarify that this is about dumping unrecognized language/version codes?

# RUN: llvm-mc -triple=x86_64--linux -filetype=obj < %s | \
# RUN: llvm-dwarfdump -v - | FileCheck %s
# RUN: llvm-mc -triple=x86_64--linux -filetype=obj -o %t.o < %s
# RUN: llvm-dwarfdump -v %t.o | FileCheck %s --check-prefix=VERBOSE
# RUN: llvm-dwarfdump %t.o | FileCheck %s --check-prefix=NO-VERBOSE

# 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)
# CHECK: DW_AT_language_version [DW_FORM_data2] (0)
# VERBOSE: .debug_abbrev contents:
# VERBOSE: DW_AT_language_version DW_FORM_data4
# VERBOSE: DW_AT_language_version DW_FORM_data2
# VERBOSE: .debug_info contents:
# VERBOSE: DW_AT_language_version [DW_FORM_data4] (201402)
# VERBOSE: DW_AT_language_version [DW_FORM_data2] (0)

# NO-VERBOSE: .debug_info contents:
# NO-VERBOSE: DW_AT_language_version (201402)
# NO-VERBOSE: DW_AT_language_version (0)

.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
Expand Down
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