Ensure every string literal is wrapped inside macro

Question

I want to wrap every string literal in my project with a macro. I want to make sure every string literal in my project is wrapped with a macro, and have some external tool help provide me the location in which there's a string literal not wrapped in a macro.

Is there any way I could use Clang Plugins to ensure that every string literal is wrapped inside macro?

Cases I want to handle:

1. #define MY_ASSERT(Y) {if(!(Y)) throw Exception(#Y); }
   

   The #Y should be warned as unwrapped string literal.

2. "a" "b" "c"
   

   It will require that the whole thing will be inside a macro, like this:

   MY_STR("a" "b" "c")
   

How could I do that with Clang plugin, or is there an other way in general to do it?

Answer 1

You could do that with the DMS Software Reengineering Toolkit and its C++ front end.

DMS can read source code according it the explicit grammar definition of C++ (handles C++17 in GCC and MS dialects), builds an AST, applies rewrite rules supplied to modify the tree, and then prettyprints the AST back to source text, preserving comments, text alignments, number radixes, etc.

To do this, you need just one DMS rule (see DMS Rewrite Rules for details):

rule wrap_string_in_macro(s:string_literal):primary_expression->primary_expression
 = "\s" -> " my_macro_name(\s) ";

The nonterminal string_literal covers the wide variety of C++ strings (8bit, ISO, wide, raw, sequence of strings, ...) so you don't have to worry about them, this rule will pick them up. But your macro might need to worry about those. So you could arguably write a larger set of rules so you can specialize the macro call:

rule wrap_ISO_string_in_macro(s:ISO_STRING_LITERAL):primary_expression->primary_expression
 = "\s" -> " my_macro_name_for_ISO_string(\s) ";

rule wrap_ISO_string_in_macro(s:WIDE_STRING_LITERAL):primary_expression->primary_expression
 = "\s" -> " my_macro_name_for_wide_string(\s) ";

...

These rules will pick up individual strings, but that leaves the problem of handling sequences of strings:

rule wrap_ISO_string_list_in_macro(seq: string_literal_list,s:ISO_STRING_LITERAL):primary_expression->primary_expression
 = " \string_literal_list \s" -> " my_macro_name_for_ISO_string_list(\s) ";

...