[+linux-sparse and Chris] On Mon, Nov 18, 2013 at 01:33:49AM +0000, Al Viro wrote: > On Sun, Nov 17, 2013 at 02:45:05PM -0800, Joe Perches wrote: > > Yes. I think it's a defect in how sparse > > treats string concatenation. > > > > That style [... with printk ...] is pretty common in the kernel sources. > > ... and it's perfectly fine, until somebody starts playing in nasal > daemon country and do that in *macro* arguments. And a nasal daemon > country it is - it's an undefined behaviour. See 6.10.3p11 in C99. > And trying to define a semantics for that gets real ugly real fast. > sparse matches gcc behaviour (I hope), but it warns about such abuses. > It's a defect, all right - one being reported by sparse. Perhaps the following tweak to the error message would make this subtlety clearer? Cheers, Greg From: Greg Price <price@xxxxxxx> Date: Sun, 17 Nov 2013 17:57:41 -0800 Subject: [PATCH] Clarify error on directive in macro arguments Preprocessor directives in the arguments of a real function are innocuous and in some contexts common. If a developer doesn't realize that a "function" is implemented as a macro, they may mistake this error for a false alarm. See http://www.spinics.net/lists/kernel/msg1636974.html and http://www.spinics.net/lists/kernel/msg1636976.html for an example. Easy enough to clarify that this is a macro, so do it. Signed-off-by: Greg Price <price@xxxxxxx> --- pre-process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/pre-process.c b/pre-process.c index d521318..db58a97 100644 --- a/pre-process.c +++ b/pre-process.c @@ -204,7 +204,7 @@ static struct token *collect_arg(struct token *prev, int vararg, struct position if (next->pos.newline && match_op(next, '#')) { if (!next->pos.noexpand) { sparse_error(next->pos, - "directive in argument list"); + "directive in macro argument list"); preprocessor_line(stream, p); __free_token(next); /* Free the '#' token */ continue; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
