[lldb] Fix another instance where we pass a nullptr as TypeSourceInfo to NonTypeTemplateParmDecl::Create

[teemperor]

Summary

Follow up to an issue pointed out in the review of D73808. We shouldn't just pass in a nullptr TypeSourceInfo
in case Clang decided to access it.

[teemperor]

• Fix a typo.

[vsk]

lgtm, thanks!

[vsk]

We have test coverage for this already, not sure why the sanitizer bot hasn't flagged this already: http://lab.llvm.org:8080/coverage/coverage-reports/coverage/Users/buildslave/jenkins/workspace/coverage/llvm-project/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp.html#L1302

[teemperor]

In D73946#1857244, @vsk wrote:

We have test coverage for this already, not sure why the sanitizer bot hasn't flagged this already: http://lab.llvm.org:8080/coverage/coverage-reports/coverage/Users/buildslave/jenkins/workspace/coverage/llvm-project/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp.html#L1302

I think assigning a nullptr is fin as the constructor doesn't deference it. But I guess touching the decl in wrong way will cause Clang to touch the TypeSourceInfo?

[vsk]

In D73946#1857400, @teemperor wrote:

In D73946#1857244, @vsk wrote:

We have test coverage for this already, not sure why the sanitizer bot hasn't flagged this already: http://lab.llvm.org:8080/coverage/coverage-reports/coverage/Users/buildslave/jenkins/workspace/coverage/llvm-project/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp.html#L1302

I think assigning a nullptr is fin as the constructor doesn't deference it. But I guess touching the decl in wrong way will cause Clang to touch the TypeSourceInfo?

Makes sense.

[shafik]

Thank you fixing this!

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

static TemplateParameterList *CreateTemplateParameterList(
   if (template_param_infos.packed_args) {
     IdentifierInfo *identifier_info = nullptr;
     if (template_param_infos.pack_name && template_param_infos.pack_name[0])
       identifier_info = &ast.Idents.get(template_param_infos.pack_name);
     const bool parameter_pack_true = true;
 
     if (!template_param_infos.packed_args->args.empty() &&
         IsValueParam(template_param_infos.packed_args->args[0])) {
+      QualType template_param_type =
+          template_param_infos.packed_args->args[0].getIntegralType();
       template_param_decls.push_back(NonTypeTemplateParmDecl::Create(
           ast, decl_context, SourceLocation(), SourceLocation(), depth,
-          num_template_params, identifier_info,
-          template_param_infos.packed_args->args[0].getIntegralType(),
-          parameter_pack_true, nullptr));
+          num_template_params, identifier_info, template_param_type,
+          parameter_pack_true,
+          ast.getTrivialTypeSourceInfo(template_param_type)));
     } else {
       template_param_decls.push_back(TemplateTypeParmDecl::Create(
           ast, decl_context, SourceLocation(), SourceLocation(), depth,
           num_template_params, identifier_info, is_typename,
           parameter_pack_true));
     }
   }
   clang::Expr *const requires_clause = nullptr; // TODO: Concepts