[Bug c/85487] Support '#pragma region' and '#pragma endregion' to allow code folding with Visual Studio

["egallager at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85487

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=61593
                 CC|                            |egallager at gcc dot gnu.org

--- Comment #10 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #3)
> The docs raise some questions.
> 
> They say that a #pragma region must be ended by a #pragma endregion. Should
> the compiler check that and issue a diagnostic otherwise?
> 
> What is the form of the optional "name" that follows #pragma region?
> 
> What if #pragma endregion is followed by preprocessor tokens, not just a
> comment?
> 
> If we don't care about validating anything, it's easy to make GCC completely
> ignore those pragmas:
> 
> --- a/gcc/c-family/c-pragma.cc
> +++ b/gcc/c-family/c-pragma.cc
> @@ -1218,6 +1218,15 @@ handle_pragma_message (cpp_reader *ARG_UNUSED(dummy))
>             TREE_STRING_POINTER (message));
>  }
>  
> +/* Ignore a no-op pragma that GCC recognizes, but which has no effect.  */
> +static void
> +handle_pragma_ignore (cpp_reader *)
> +{
> +  tree x;
> +  while (pragma_lex (&x) != CPP_EOF)
> +    /* Ignore the rest of the line.  */;
> +}
> +
>  /* Mark whether the current location is valid for a STDC pragma.  */
>  
>  static bool valid_location_for_stdc_pragma;
> @@ -1633,6 +1642,9 @@ init_pragma (void)
>    c_register_pragma ("GCC", "pop_options", handle_pragma_pop_options);
>    c_register_pragma ("GCC", "reset_options", handle_pragma_reset_options);
>  
> +  c_register_pragma (0, "region", handle_pragma_ignore);
> +  c_register_pragma (0, "endregion", handle_pragma_ignore);
> +
>    c_register_pragma ("STDC", "FLOAT_CONST_DECIMAL64",
>                      handle_pragma_float_const_decimal64);
>  
> 
> 
> This needs tests though.

so, this seems relevant to bug 61593 too...