[Bug c++/53431] C++ preprocessor ignores #pragma GCC diagnostic

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431

--- Comment #9 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Manuel López-Ibáñez from comment #5)
> The C++ parser lexes (and preprocesses) before handling the pragmas, whereas
> the C parser processes the pragmas as it sees them.
> 
> We must somehow parse these pragmas *also* in cp/parser.c:631. Maybe one can
> do something similar to what we do for cp_parser_initial_pragma, but within
> the loop and only handling pragma diagnostic. Surely, it will need some
> trial and error to get it right. If any of you wants to give it a try and
> need some help, just ask here or in the mailing list.

There are two problems that need fixing to implement this:

1. At the point the pragma is lexed we don't know that this is pragma GCC
diagnostic, since the pragmas are registered dynamically and there is no (enum
pragma_kind) PRAGMA_GCC_DIAGNOSTIC. Perhaps one could do what is done for
PRAGMA_GCC_PCH_PREPROCESS.

2. The second problem is that handle_pragma_diagnostic does not work during
lexing (at least for C++). We would need to rewrite the whole function and call
it directly.
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From: "dominiq at lps dot ens.fr" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug bootstrap/63188] [5 Regression] r214954 breaks bootstrap on x86_64-apple-darwin13
Date: Fri, 05 Sep 2014 17:57:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idc188

--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Bootstrap of revision r214972 with the patch

--- ../_clean/gcc/config/darwin.h    2014-06-27 18:25:13.000000000 +0200
+++ gcc/config/darwin.h    2014-09-05 18:28:29.000000000 +0200
@@ -499,7 +499,7 @@ extern GTY(()) int darwin_ms_struct;
 #define NO_PROFILE_COUNTERS    1

 #undef    INIT_SECTION_ASM_OP
-#define INIT_SECTION_ASM_OP
+#define INIT_SECTION_ASM_OP ""

 #undef    INVOKE__main

just completed, testing in progress.