Print the "no plugin" warning only when there is no plugin

[aprantl]

Summary

Print the "no plugin" warning only when there is no plugin and not when the typesystem failed to initialize.

rdar://72562341

[shafik]

Can we test this?

[JDevlieghere]

In D95992#2540921, @shafik wrote:

Can we test this?

If you can bypass the check for a valid module on line 5682, you might be able to write a unit test by setting the function in the SymbolContext to return an unsupported language.

[aprantl]

The feature itself is already being tested by lldb/test/Shell/Process/UnsupportedLanguage.test. In order to test this change we would have to force TypeSystemClang to fail to initialize somehow. The only way to do this would be to pass in an invalid arch, but if we do that we won't get to the point where this warning would be printed. (The bugfix is intended for Swift plugin, which does fail to initialize more easily).

[JDevlieghere]

Perfect, then this LGTM.

lldb/source/Target/Process.cpp

 void Process::PrintWarningUnsupportedLanguage(const SymbolContext &sc) {
   if (!GetWarningsUnsupportedLanguage())
     return;
   if (!sc.module_sp)
     return;
   LanguageType language = sc.GetLanguage();
   if (language == eLanguageTypeUnknown)
     return;
-  auto type_system_or_err = sc.module_sp->GetTypeSystemForLanguage(language);
-  if (auto err = type_system_or_err.takeError()) {
-    llvm::consumeError(std::move(err));
+  LanguageSet plugins =
+      PluginManager::GetAllTypeSystemSupportedLanguagesForTypes();
+  if (!plugins[language]) {
     PrintWarning(Process::Warnings::eWarningsUnsupportedLanguage,
                  sc.module_sp.get(),
                  "This version of LLDB has no plugin for the %s language. "
                  "Inspection of frame variables will be limited.\n",
                  Language::GetNameForLanguageType(language));
   }
 }