Re: [PATCH] Teach sparse about the __COUNTER__ predefined macro

[josh@joshtriplett.org]

On Fri, Jan 23, 2015 at 11:23:32PM +0100, Luc Van Oostenryck wrote:
> On Fri, Jan 23, 2015 at 08:40:17AM -0800, Christopher Li wrote:
> > I think sparse haven't implement the __COUNTER__ macro. That is why it emit the
> > error on duplicate entry.
> 
> The following patch should fix that.
[...]
> Subject: [PATCH] Teach sparse about the __COUNTER__ predefined macro.
> 
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>

One issue below.

> --- a/pre-process.c
> +++ b/pre-process.c
> @@ -181,6 +181,10 @@ static int expand_one_symbol(struct token **list)
>  			time(&t);
>  		strftime(buffer, 9, "%T", localtime(&t));
>  		replace_with_string(token, buffer);
> +	} else if (token->ident == &__COUNTER___ident) {
> +		static int counter;
> +
> +		replace_with_integer(token, counter++);

This should not use a static counter.  GCC and Sparse can run over more
than one file in one invocation:

$ head test1.c test2.c
==> test1.c <==
__COUNTER__
__COUNTER__

==> test2.c <==
__COUNTER__
__COUNTER__

$ gcc -E test1.c test2.c
# 1 "test1.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test1.c"
0
1
# 1 "test2.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test2.c"
0
1

Notice that the second file starts with __COUNTER__ at 0 again.

The counter *should* keep counting through include files, but needs to
reset before starting a new top-level compile.

- Josh Triplett