[llvm][dwarfdump] Pretty-print DW_AT_language_version

llvm/lib/DebugInfo/DWARF/DWARFDie.cpp

@@ -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) {
@@ -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);
+  bool ShouldDumpRawLanguageVersion =
+      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()))) {
@@ -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";

llvm/test/DebugInfo/Generic/compileunit-source-language-name.ll

@@ -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

llvm/test/tools/llvm-dwarfdump/X86/DW_AT_language_version-pretty.s

@@ -0,0 +1,44 @@
+# 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)
+# VERBOSE: DW_AT_language_name [DW_FORM_data2] (0x0000)
+# VERBOSE: DW_AT_language_version [DW_FORM_data4] (12 Unknown)
+
+# NO-VERBOSE: .debug_info contents:
+# NO-VERBOSE: DW_AT_language_name (DW_LNAME_C)
+# NO-VERBOSE: DW_AT_language_version (C11)
+# NO-VERBOSE: DW_AT_language_name (0x0000)
+# NO-VERBOSE: DW_AT_language_version (Unknown)
+
+        .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   1                       # Abbrev [1] DW_TAG_compile_unit
+        .short  0                       # DW_AT_language_name
+        .long   12                      # DW_AT_language_version
+        .byte   0 
+.Ldebug_info_end0:

llvm/test/tools/llvm-dwarfdump/X86/DW_AT_language_version.s

@@ -1,13 +1,19 @@
-# Demonstrate dumping DW_AT_language_version.
-# RUN: llvm-mc -triple=x86_64--linux -filetype=obj < %s | \
-# RUN:     llvm-dwarfdump -v - | FileCheck %s
+# Demonstrate dumping DW_AT_language_version without an
+# accompanying DW_AT_language_name.
+# 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