[llvm] [llvm][Dwarf] Add LanguageDescription API that accounts for version (PR #162048)

Michael Buch via llvm-commits llvm-commits at lists.llvm.org
Wed Oct 8 00:43:20 PDT 2025


https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/162048

>From 544d86112320b1512e3ce3aaa11d177f47d5e206 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 6 Oct 2025 09:37:51 +0100
Subject: [PATCH 1/5] [llvm][Dwarf] Add LanguageDescription API that accounts
 for version

Currently `llvm::dwarf::LanguageDescription` returns a stringified
`DW_LNAME`. It would be useful to have an API that returns the language
name for a particular `DW_LNAME_`/version pair. LLDB's use case is that
it wants to display a human readable description of the language we got
from debug-info in diagnostics. We could maintain a side-table in LLDB
but though this might generally be useful to live next to the
`LanguageDescription` API.
---
 llvm/include/llvm/BinaryFormat/Dwarf.h |   5 ++
 llvm/lib/BinaryFormat/Dwarf.cpp        | 111 +++++++++++++++++++++++++
 2 files changed, 116 insertions(+)

diff --git a/llvm/include/llvm/BinaryFormat/Dwarf.h b/llvm/include/llvm/BinaryFormat/Dwarf.h
index 2c5012510a5c3..de29f14097fb8 100644
--- a/llvm/include/llvm/BinaryFormat/Dwarf.h
+++ b/llvm/include/llvm/BinaryFormat/Dwarf.h
@@ -500,8 +500,13 @@ toDW_LNAME(SourceLanguage language) {
   return {};
 }
 
+/// Returns a version-independent language name.
 LLVM_ABI llvm::StringRef LanguageDescription(SourceLanguageName name);
 
+/// Returns a language name corresponding to the specified version.
+LLVM_ABI llvm::StringRef LanguageDescription(SourceLanguageName Name,
+                                             uint32_t Version);
+
 inline bool isCPlusPlus(SourceLanguage S) {
   bool result = false;
   // Deliberately enumerate all the language options so we get a warning when
diff --git a/llvm/lib/BinaryFormat/Dwarf.cpp b/llvm/lib/BinaryFormat/Dwarf.cpp
index 8b24044e19e50..8e87c68424e00 100644
--- a/llvm/lib/BinaryFormat/Dwarf.cpp
+++ b/llvm/lib/BinaryFormat/Dwarf.cpp
@@ -472,6 +472,117 @@ StringRef llvm::dwarf::LanguageDescription(dwarf::SourceLanguageName lname) {
   return "Unknown";
 }
 
+StringRef llvm::dwarf::LanguageDescription(dwarf::SourceLanguageName Name,
+                                           uint32_t Version) {
+  switch (Name) {
+  // YYYY
+  case DW_LNAME_Ada: {
+    if (Version <= 1983)
+      return "Ada 83";
+    if (Version <= 1995)
+      return "Ada 95";
+    if (Version <= 2005)
+      return "Ada 2005";
+    if (Version <= 2012)
+      return "Ada 2012";
+  } break;
+
+  case DW_LNAME_Cobol: {
+    if (Version <= 1974)
+      return "COBOL-74";
+    if (Version <= 1985)
+      return "COBOL-85";
+  } break;
+
+  case DW_LNAME_Fortran: {
+    if (Version <= 1977)
+      return "FORTRAN 77";
+    if (Version <= 1990)
+      return "FORTRAN 90";
+    if (Version <= 1995)
+      return "Fortran 95";
+    if (Version <= 2003)
+      return "Fortran 2003";
+    if (Version <= 2008)
+      return "Fortran 2008";
+    if (Version <= 2018)
+      return "Fortran 2018";
+  } break;
+
+  // YYYYMM
+  case DW_LNAME_C: {
+    if (Version == 0)
+      return "K&R C";
+    if (Version <= 198912)
+      return "C89";
+    if (Version <= 199901)
+      return "C99";
+    if (Version <= 201112)
+      return "C11";
+    if (Version <= 201710)
+      return "C17";
+  } break;
+
+  case DW_LNAME_C_plus_plus: {
+    if (Version == 0)
+      break;
+    if (Version <= 199711)
+      return "C++98";
+    if (Version <= 200310)
+      return "C++03";
+    if (Version <= 201103)
+      return "C++11";
+    if (Version <= 201402)
+      return "C++14";
+    if (Version <= 201703)
+      return "C++17";
+    if (Version <= 202002)
+      return "C++20";
+  } break;
+
+  case DW_LNAME_ObjC_plus_plus:
+  case DW_LNAME_ObjC:
+  case DW_LNAME_Move:
+  case DW_LNAME_SYCL:
+  case DW_LNAME_BLISS:
+  case DW_LNAME_Crystal:
+  case DW_LNAME_D:
+  case DW_LNAME_Dylan:
+  case DW_LNAME_Go:
+  case DW_LNAME_Haskell:
+  case DW_LNAME_HLSL:
+  case DW_LNAME_Java:
+  case DW_LNAME_Julia:
+  case DW_LNAME_Kotlin:
+  case DW_LNAME_Modula2:
+  case DW_LNAME_Modula3:
+  case DW_LNAME_OCaml:
+  case DW_LNAME_OpenCL_C:
+  case DW_LNAME_Pascal:
+  case DW_LNAME_PLI:
+  case DW_LNAME_Python:
+  case DW_LNAME_RenderScript:
+  case DW_LNAME_Rust:
+  case DW_LNAME_Swift:
+  case DW_LNAME_UPC:
+  case DW_LNAME_Zig:
+  case DW_LNAME_Assembly:
+  case DW_LNAME_C_sharp:
+  case DW_LNAME_Mojo:
+  case DW_LNAME_GLSL:
+  case DW_LNAME_GLSL_ES:
+  case DW_LNAME_OpenCL_CPP:
+  case DW_LNAME_CPP_for_OpenCL:
+  case DW_LNAME_Ruby:
+  case DW_LNAME_Hylo:
+  case DW_LNAME_Metal:
+    break;
+  }
+
+  // Fallback to un-versioned name.
+  return LanguageDescription(Name);
+}
+
 StringRef llvm::dwarf::CaseString(unsigned Case) {
   switch (Case) {
   case DW_ID_case_sensitive:

>From bb068b99b8271a82ac03ef4cb9d8f809e5190f76 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 6 Oct 2025 09:46:51 +0100
Subject: [PATCH 2/5] fixup! expand docs

---
 llvm/include/llvm/BinaryFormat/Dwarf.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/llvm/include/llvm/BinaryFormat/Dwarf.h b/llvm/include/llvm/BinaryFormat/Dwarf.h
index de29f14097fb8..624e5f63f2270 100644
--- a/llvm/include/llvm/BinaryFormat/Dwarf.h
+++ b/llvm/include/llvm/BinaryFormat/Dwarf.h
@@ -504,6 +504,8 @@ toDW_LNAME(SourceLanguage language) {
 LLVM_ABI llvm::StringRef LanguageDescription(SourceLanguageName name);
 
 /// Returns a language name corresponding to the specified version.
+/// If the version is not recognized for the specified language, returns
+/// the version-independent name.
 LLVM_ABI llvm::StringRef LanguageDescription(SourceLanguageName Name,
                                              uint32_t Version);
 

>From 478528e8d2b0f2859f7c9ff61176ab466f40a27e Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 6 Oct 2025 09:59:36 +0100
Subject: [PATCH 3/5] fixup! handle C version 0

---
 llvm/lib/BinaryFormat/Dwarf.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/BinaryFormat/Dwarf.cpp b/llvm/lib/BinaryFormat/Dwarf.cpp
index 8e87c68424e00..0202dffc3d6b2 100644
--- a/llvm/lib/BinaryFormat/Dwarf.cpp
+++ b/llvm/lib/BinaryFormat/Dwarf.cpp
@@ -512,7 +512,7 @@ StringRef llvm::dwarf::LanguageDescription(dwarf::SourceLanguageName Name,
   // YYYYMM
   case DW_LNAME_C: {
     if (Version == 0)
-      return "K&R C";
+      break;
     if (Version <= 198912)
       return "C89";
     if (Version <= 199901)

>From f50c0b10e8d0f627e91a1c36225cde92486545f4 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 6 Oct 2025 18:15:21 +0100
Subject: [PATCH 4/5] fixup! unittests

---
 .../DebugInfo/DWARF/DWARFDebugInfoTest.cpp    | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp b/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
index 373a58d259af5..ae7960e948801 100644
--- a/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
@@ -2276,4 +2276,46 @@ TEST(DWARFDebugInfo, TestDWARF64UnitLength) {
   });
 }
 
+TEST(DWARFDebugInfo, TestLanguageDescription_Versioned) {
+  // Tests for the llvm::dwarf::LanguageDescription API that
+  // takes a name *and* a version.
+
+  // Unknown language.
+  EXPECT_EQ(
+      llvm::dwarf::LanguageDescription(static_cast<SourceLanguageName>(0)),
+      "Unknown");
+
+  // Test that specifying an invalid version falls back to a valid language name
+  // regardless.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(
+                static_cast<SourceLanguageName>(DW_LNAME_ObjC), 0),
+            "Objective C");
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(
+                static_cast<SourceLanguageName>(DW_LNAME_Julia), 0),
+            "Julia");
+
+  // Check some versions.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 199711),
+            "C++98");
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 201402),
+            "C++14");
+
+  // Versions round up.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 201400),
+            "C++14");
+
+  // Version 0 for C and C++ is an unversioned name.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(
+                static_cast<SourceLanguageName>(DW_LNAME_C), 0),
+            "C (K&R and ISO)");
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(
+                static_cast<SourceLanguageName>(DW_LNAME_C_plus_plus), 0),
+            "ISO C++");
+
+  // Version 0 for other versioned languages may not be the unversioned name.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(
+                static_cast<SourceLanguageName>(DW_LNAME_Fortran), 0),
+            "FORTRAN 77");
+}
+
 } // end anonymous namespace

>From f3227108ac992aa1e86e28f18439549bfcea7551 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Wed, 8 Oct 2025 08:43:01 +0100
Subject: [PATCH 5/5] fixup! move tests, remove redundant casts

---
 llvm/unittests/BinaryFormat/DwarfTest.cpp     | 38 ++++++++++++++++
 .../DebugInfo/DWARF/DWARFDebugInfoTest.cpp    | 43 -------------------
 2 files changed, 38 insertions(+), 43 deletions(-)

diff --git a/llvm/unittests/BinaryFormat/DwarfTest.cpp b/llvm/unittests/BinaryFormat/DwarfTest.cpp
index 684e59fa2785c..48463794f9d63 100644
--- a/llvm/unittests/BinaryFormat/DwarfTest.cpp
+++ b/llvm/unittests/BinaryFormat/DwarfTest.cpp
@@ -219,4 +219,42 @@ TEST(DwarfTest, lname) {
   EXPECT_EQ(roundtrip(DW_LANG_##NAME), DW_LANG_##NAME);
 #include "llvm/BinaryFormat/Dwarf.def"
 }
+
+TEST(DWARFDebugInfo, TestLanguageDescription_Versioned) {
+  // Tests for the llvm::dwarf::LanguageDescription API that
+  // takes a name *and* a version.
+
+  // Unknown language.
+  EXPECT_EQ(
+      llvm::dwarf::LanguageDescription(static_cast<SourceLanguageName>(0)),
+      "Unknown");
+
+  EXPECT_EQ(
+      llvm::dwarf::LanguageDescription(static_cast<SourceLanguageName>(0), 0),
+      "Unknown");
+
+  // Test that specifying an invalid version falls back to a valid language name
+  // regardless.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_ObjC, 0), "Objective C");
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_Julia, 0), "Julia");
+
+  // Check some versions.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 199711),
+            "C++98");
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 201402),
+            "C++14");
+
+  // Versions round up.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 201400),
+            "C++14");
+
+  // Version 0 for C and C++ is an unversioned name.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C, 0), "C (K&R and ISO)");
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 0),
+            "ISO C++");
+
+  // Version 0 for other versioned languages may not be the unversioned name.
+  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_Fortran, 0),
+            "FORTRAN 77");
+}
 } // end namespace
diff --git a/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp b/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
index ae7960e948801..49773196129a8 100644
--- a/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
@@ -2275,47 +2275,4 @@ TEST(DWARFDebugInfo, TestDWARF64UnitLength) {
     ASSERT_EQ(0x1122334455667788ULL, CU.getLength());
   });
 }
-
-TEST(DWARFDebugInfo, TestLanguageDescription_Versioned) {
-  // Tests for the llvm::dwarf::LanguageDescription API that
-  // takes a name *and* a version.
-
-  // Unknown language.
-  EXPECT_EQ(
-      llvm::dwarf::LanguageDescription(static_cast<SourceLanguageName>(0)),
-      "Unknown");
-
-  // Test that specifying an invalid version falls back to a valid language name
-  // regardless.
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(
-                static_cast<SourceLanguageName>(DW_LNAME_ObjC), 0),
-            "Objective C");
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(
-                static_cast<SourceLanguageName>(DW_LNAME_Julia), 0),
-            "Julia");
-
-  // Check some versions.
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 199711),
-            "C++98");
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 201402),
-            "C++14");
-
-  // Versions round up.
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(DW_LNAME_C_plus_plus, 201400),
-            "C++14");
-
-  // Version 0 for C and C++ is an unversioned name.
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(
-                static_cast<SourceLanguageName>(DW_LNAME_C), 0),
-            "C (K&R and ISO)");
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(
-                static_cast<SourceLanguageName>(DW_LNAME_C_plus_plus), 0),
-            "ISO C++");
-
-  // Version 0 for other versioned languages may not be the unversioned name.
-  EXPECT_EQ(llvm::dwarf::LanguageDescription(
-                static_cast<SourceLanguageName>(DW_LNAME_Fortran), 0),
-            "FORTRAN 77");
-}
-
 } // end anonymous namespace



More information about the llvm-commits mailing list