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From: "austinpmorton at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/85487] Support '#pragma region' and '#pragma endregion' to
 allow code folding with Visual Studio
Date: Tue, 15 Feb 2022 14:02:51 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D85487

--- Comment #5 from Austin Morton <austinpmorton at gmail dot com> ---

(In reply to Jonathan Wakely from comment #3)
> The docs raise some questions.
>=20
> They say that a #pragma region must be ended by a #pragma endregion. Shou=
ld
> the compiler check that and issue a diagnostic otherwise?
>=20
> What is the form of the optional "name" that follows #pragma region?
>=20
> What if #pragma endregion is followed by preprocessor tokens, not just a
> comment?
>=20
> If we don't care about validating anything, it's easy to make GCC complet=
ely
> ignore those pragmas:
>=20
> --- 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(dumm=
y))
>             TREE_STRING_POINTER (message));
>  }
>=20=20
> +/* 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) !=3D CPP_EOF)
> +    /* Ignore the rest of the line.  */;
> +}
> +
>  /* Mark whether the current location is valid for a STDC pragma.  */
>=20=20
>  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=
);
>=20=20
> +  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);
>=20=20
>=20
>=20
> This needs tests though.

https://gcc.gnu.org/pipermail/gcc-patches/2020-September/553182.html

I sent a patch to do exactly that in 2020 and it was not accepted.

This seems like a very easy win.
Both major competitors to GCC (clang and MSVC) implement this pragma exactly
like in my patch (by completely ignoring it).

As it stands today, this is plainly a deficiency in GCC when compared to its
competition.=