From mboxrd@z Thu Jan  1 00:00:00 1970
From: johannes@sipsolutions.net (Johannes Berg)
Date: Fri, 27 Jan 2017 22:43:57 +0100
Subject: [Cocci] modifying initializers with spatch?
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To: cocci@systeme.lip6.fr
List-Id: cocci@systeme.lip6.fr


> > To get rid of all the initializers, but (as I'm still on the phone)
> > I haven't tried it yet :)
> > 
> 
> Put a when any above the T x = line.
> 
> On the other hand, ++ makes no guarantee about the order in which
> things are generated.
> 
> To ensure the order, put the when any above the T x line, and drop
> the one below and run multiple times.??Then each run will work on the
> last one and put it first, so they will come out in order.

Finally got a chance to try this.

I can't seem to get the ordering right. I'm trying this:

@@
type T;
expression E;
statement S1, S2;
identifier x;
identifier f;
@@
?{
... when != { ... }
????when any
?T x = {
-??.f = E,
?};
... when != S1
+ x.f = E;
?S2
?...
?}

on a very simple file:

int main()
{
	struct foo bar = {
		.y = 8,
		.x = 7,
	};

	printf("%d\n", bar.x);
	printf("%d\n", bar.y);
}

but it doesn't end well:

$ spatch??--sp-file /tmp/init.spatch /tmp/test.c
init_defs_builtins: /usr/lib/coccinelle/standard.h
HANDLING: /tmp/test.c
?????
previous modification:

? <<< x.f = E;
CONTEXT
According to environment 3:
???rule starting on line 1.E -> 8
???rule starting on line 1.f -> id y
???rule starting on line 1.x -> id bar

current modification:

? <<< x.f = E;
CONTEXT
According to environment 3:
???rule starting on line 1.E -> 7
???rule starting on line 1.f -> id x
???rule starting on line 1.x -> id bar

Fatal error: exception Failure("rule starting on line 1: already tagged
token:\nC code context\nFile \"/tmp/test.c\", line 8, column
1,??charpos = 59\n????around = 'printf', whole content =
\tprintf(\"%d\\n\", bar.x);")


If I use ++ instead of +, it still replaces all of them, so I can't run
multiple times (usefully anyway)

OTOH, I haven't found any place where the order actually matters (in
the code base I'm interested in), and although it seems that it
theoretically could matter, I'm not sure I really need to solve that
problem - although I'm thinking I might want to run this not just once
but before each compile, to keep the code neater.

(Note that I also haven't upgraded to the git version yet, TBD)

johannes