Re: Fwd: dependency tee from c parser entities downto token

[Christopher Li <sparse@chrisli.org>]

On Mon, May 7, 2012 at 11:38 PM, Konrad Eisele <konrad@gaisler.com> wrote:
>
> Yea, I think it is better that way. You should implement it yourself first,
> it kind of takes too long otherwise :-). Still I'm kind of
> curious how you can trace macro expansion with just 1 callback
> but I'll like to be surprised.

OK, there is the initial version of the preprocessor hook.
I create an branch "unclean-preprocess-hook" for review.

http://git.kernel.org/?p=devel/sparse/chrisl/sparse.git;a=shortlog;h=refs/heads/unclean-preprocess-hook

I end up use more than one call back, but it is still better that 6.
I also think that is easier for the caller to use. because it receive the
the before and after at the same time.


struct preprocess_hook {
	void (*expand_macro)(struct token *macro, struct symbol *sym,
			     struct token **replace, struct token **replace_tail);
	void (*expand_arg)(struct token *macro, struct symbol *sym, int arg,
			   struct token *orig, struct token *expanded);
};

The demo program expand your example macro with the following
results:

<beginning of 't.c'>
#define D0(d0a0,d0a1) 1 D1(d0a0) 2 D2(d0a1) 3
#define D1(d1a0) 4 d1a0 5
#define D2(d2a0) 6 d2a0 7
#define D3(d3a0) 8 d3a0 9
D0(D3(10),11)<end of 't.c'>
arg0 in D3 :10 -> 10
macro D3 inside D0
expand result: 8 10 9 <untaint: D3>
arg0 in D0 :D3(10) -> 8 10 9
arg1 in D0 :11 -> 11
macro D0 inside <noident>
expand result: 1 D1(8 10 9) 2 D2(11) 3 <untaint: D0>
arg0 in D1 :8 10 9 -> 8 10 9
macro D1 inside D0
expand result: 4 8 10 9 5 <untaint: D1>
arg0 in D2 :11 -> 11
macro D2 inside D0
expand result: 6 11 7 <untaint: D2>
After preprocessing
1 4 8 10 9 5 2 6 11 7 3

A few things. I don't think you need to manipulate the define for empty
body macro any more. You should be able to find out the macro expand
to empty in the hook.

I still haven't fully understand why you need the empty token type. However
there is the untaint token which mark the end of the a macro expand. You
might able to use that as well.

This branch needs cleanup before merge to the upstream.
Please let me know what I miss.

Chris