On Tue, 2018-09-11 at 11:05 +0200, Julia Lawall wrote: > > On Tue, 11 Sep 2018, Luca Coelho wrote: > > > Hi Julia, > > > > I bumped in to another weird problem. I'm trying to match some > > code > > inside a function that has a specific struct as a parameter, but I > > can't get it to work. > > > > This is cocci code I tried first: > > > > http://pastebin.coelho.fi/6f8f346822a7c99e.txt > > > > And this is the file I'm trying to match: > > > > http://pastebin.coelho.fi/f73f542932add1c6.txt > > > > The led activate op changed from being a function that returns void > > to > > one that returns int and I had to backport that. > > > > The strange thing is that if I have only the first rule, it works > > fine, > > but when I add the second rule it fails. > > I didn't look at the code in detail, but there is a restriction on > metavariables that are not position variables that are inherited from > one > rule to another. Such metavariables have to have only one value. If > there is more than one possible value, the original match fails > completely. > > For example, if you do: > > @r@ > expression E; > @@ > > f(); > ... > -g(E); > > This will do the right thing for: > > f(); > if (x) > g(3); > else g(4); > > But if you do: > > @r@ > expression E; > @@ > > f(); > ... > -g(E); > > @@ > expression r.E; > @@ > > - xxx(E); > > Then nothing will happen at all. Because in the first rule, it is > not > able to find a unique binding for E. > > A solution can be: > > @r@ > expression E; > position p; > @@ > > f(); > ... > g(E@p); > > @s@ > position r.p; > expression E; > @@ > > - g(E@p); > > @@ > expression s.E; > @@ > > - xxx(E); > > Position metavariable can take on many values, even if they are > inherited. Ah, I think this explains the problem. I tried to add the position thing in my rules, but I didn't succeed. I'll have to try again at some other time. My rules without matching inside a function work fine, so I'll leave with that for now. Thanks! -- Luca. -- To unsubscribe from this list: send the line "unsubscribe backports" in
