[lldb][Language] Add Language::GetDisplayNameForLanguageType API

[Michael137]

The intention for this API is to be used when presenting language names to the user, e.g., in expression evaluation diagnostics or LLDB errors.

Most uses of GetNameForLanguageType can be probably replaced with GetDisplayNameForLanguageType, but that's out of scope of this PR.

This uses llvm::dwarf::LanguageDescription under the hood, so we would lose the version numbers in the names. If we deem those to be important, we could switch to an implementation that hardcodes a list of user-friendly names with version numbers included.

The intention is to use it from #161688

Depends on #161804

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Michael Buch (Michael137)

Changes

The intention for this API is to be used when presenting language names to the user, e.g., in expression evaluation diagnostics or LLDB errors.

Most uses of GetNameForLanguageType can be probably replaced with GetDisplayNameForLanguageType, but that's out of scope of this PR.

This uses llvm::dwarf::LanguageDescription under the hood, so we would lose the version numbers in the names. If we deem those to be important, we could switch to an implementation that hardcodes a list of user-friendly names with version numbers included.

The intention is to use it from #161688

---

Full diff: https://github.com/llvm/llvm-project/pull/161803.diff

2 Files Affected:

• (modified) lldb/include/lldb/Target/Language.h (+7)
• (modified) lldb/source/Target/Language.cpp (+4)

diff --git a/lldb/include/lldb/Target/Language.h b/lldb/include/lldb/Target/Language.h
index 3d0aa326d5a6d..48a7ac2cea42f 100644
--- a/lldb/include/lldb/Target/Language.h
+++ b/lldb/include/lldb/Target/Language.h
@@ -404,8 +404,15 @@ class Language : public PluginInterface {
   GetLanguageTypeFromString(const char *string) = delete;
   static lldb::LanguageType GetLanguageTypeFromString(llvm::StringRef string);
 
+  /// Returns the internal LLDB name for the specified language. When presenting
+  /// the language name to users, use \ref GetDisplayNameForLanguageType
+  /// instead.
   static const char *GetNameForLanguageType(lldb::LanguageType language);
 
+  /// Returns a user-friendly name for the specified language.
+  static llvm::StringRef
+  GetDisplayNameForLanguageType(lldb::LanguageType language);
+
   static void PrintAllLanguages(Stream &s, const char *prefix,
                                 const char *suffix);
 
diff --git a/lldb/source/Target/Language.cpp b/lldb/source/Target/Language.cpp
index 484d9badde397..f0fc48e18793b 100644
--- a/lldb/source/Target/Language.cpp
+++ b/lldb/source/Target/Language.cpp
@@ -270,6 +270,10 @@ const char *Language::GetNameForLanguageType(LanguageType language) {
     return language_names[eLanguageTypeUnknown].name;
 }
 
+llvm::StringRef Language::GetDisplayNameForLanguageType(LanguageType language) {
+  return SourceLanguage(language).GetDescription();
+}
+
 void Language::PrintSupportedLanguagesForExpressions(Stream &s,
                                                      llvm::StringRef prefix,
                                                      llvm::StringRef suffix) {