On Thu, May 27, 2021 at 11:55 AM Fuad Tabba <ta...@google.com> wrote:
>
> On Thu, May 27, 2021 at 11:26 AM Julia Lawall <julia.law...@inria.fr> wrote:
> >
> >
> >
> > On Thu, 27 May 2021, Julia Lawall wrote:
> >
> > >
> > >
> > > On Thu, 27 May 2021, Fuad Tabba wrote:
> > >
> > > > Hi,
> > > >
> > > > I'm trying to write a semantic patch that would add a new line to a
> > > > function, but would like that line to come after all local variables
> > > > (if any) have been declared. For example (distilled from what I am
> > > > actually trying to accomplish):
> > > >
> > > > @@
> > > > identifier f, s;
> > > > @@
> > > > f(..., struct mystruct *s, ...) {
> > > > /* after any variable declarations*/
> > > > + x = s->x;
> > > > ...
> > > > }
> > > >
> > > > I would like it to patch as follows:
> > > >
> > > > int function(struct mystruct *s) {
> > > > + x = s->x;
> > > > return 0;
> > > > }
> > > >
> > > > as well as
> > > >
> > > > int function(struct mystruct *s)
> > > > {
> > > > int y;
> > > > + x = s->x;
> > > > return 0;
> > > > }
> > > >
> > > > or
> > > >
> > > > int function(struct mystruct *s)
> > > > {
> > > > int y, z = 10;
> > > > float f;
> > > > + x = s->x;
> > > > return 0;
> > > > }
> > > >
> > > > Any suggestions on how I could do that?
> > >
> > > @@
> > > @@
> > >
> > > f(...) {
> > > ... when != S
> > > + new_code
> > > S
> > > ... when any
> > > }
> >
> > Sorry, that was not quite right. The first S should be S1 and the second
> > S should be S2, ie they should be different. S1 and S2 should be
> > statement metavariables and f should be an identifier metavariable.
>
> Thanks Julia. That works for my distilled example, but teaches me a
> lesson not to assume that the parts I've omitted aren't relevant. :)
> Here's the actual semantic patch I'm trying to write, and I can't get
> that quite to work:
>
> @@
> expression a, b;
> identifier vcpu;
> fresh identifier vcpu_ctxt = vcpu ## "_ctxt";
> iterator name kvm_for_each_vcpu;
> identifier fc;
> @@
> kvm_for_each_vcpu(a, vcpu, b)
> {
> /* hop over any declarations */
> + vcpu_ctxt = &vcpu->arch.ctxt;
> <+...
> fc(..., vcpu, ...)
> ...+>
> }
>
I managed to get it done by doing it in two steps; first using the
original semantic patch I had, then using yours essentially to move
the line I added.
Thanks again!
/fuad
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