OK, here is an example .c, a sample .h, and a script that works part of the
time.
I can spatch --all-includes -I . --sp-file <code in this email> x.c and it
gets 3 and fails 3.
I've boiled this down as much as I can from plan 9 code. BTW, the position
stuff would not work at all for me.
.c
#include "x.h"
int x(int a)
{
if (m)
return 0;
poperror();
return m->x;
}
int y(int a)
{
if (m)
return 1;
return 0;
}
void * z(int a)
{
x = m;
return &x[1];
}
int w(int a)
{
poperror();
return 1;
}
int ww(int a)
{
if (a) {
if (waserror()) {
nexterror();
}
poperror();
}
return 1;
}
.h
#define NULL (void *)0
struct Mach {
int x;
};
typedef struct Mach Mach;
Mach *m;
#define poperror() m = NULL
.cocci
@r exists@
typedef Mach; // only needed once per semantic patch
idexpression Mach *m;
function f;
@@
f(...){
<+...
m
...+>
}
@@
function r.f;
@@
f(...) {
++ Mach *m = machp();
...
}
On Thu, Apr 2, 2015 at 2:40 PM Julia Lawall <[email protected]> wrote:
>
>
> On Thu, 2 Apr 2015, ron minnich wrote:
>
> > This is not working with my 1.0.0-rc21 on ubuntu, is there a version
> you'd
> > recommend?
>
> The current release is rc24, but I don't think there is anything relevant
> that is new, except the global idea. Does it crash, or just not find
> anything? Could you send the exact semantic patch and some representative
> C code?
>
> thanks,
> julia
>
> >
> > Many thanks!
> >
> > ron
> >
> > On Thu, Apr 2, 2015 at 2:22 PM Julia Lawall <[email protected]>
> wrote:
> > > f(...){
> > > + Mach *m = machp();
> > > ...
> > > x = m
> > > ...
> > > }
> >
> > This requires there to be exactly one occurrence of x = m on
> > every (non
> > failing) execution path.
> >
> > >
> > > The x = m could also be m->x, or if (m) s, and so on
> >
> > Do you just mean any reference to m at all? Or do you mean any
> > reference
> > that is not an assignment to m, ie not m = x.
> >
> > If you want to allow any kind of reference to m, you could do:
> >
> > @r exists@
> > typedef Mach; // only needed once per semantic patch
> > idexpression Mach *m;
> > function f;
> > position p;
> > @@
> > f@p(...){
> > <+...
> > m
> > ...+>
> > }
> >
> > @@
> > identifier r.f;
> > position r.p;
> > idexpression Mach *r.m;
> > @@
> >
> > f@p(...) {
> > ++Mach *m;
> > ...
> > }
> >
> > There could be more than one Mach * typed variable in a
> > function. The ++
> > lets them all get added, but there is no way to know in what
> > order they
> > will appear.
> >
> > Otherwise, the idea here is that if there ever exists an m in
> > the
> > function, then add the declaration to the function. It might be
> > possible
> > to merge the two rules, as:
> >
> > @r exists@
> > typedef Mach; // only needed once per semantic patch
> > idexpression Mach *m;
> > function f;
> > @@
> > f(...){
> > ++ Mach *m;
> > <+...
> > m
> > ...+>
> > }
> >
> > But that might give multiple declarations of the same variable,
> > if it is
> > used in more than one execution path.
> >
> > Also, it might be possible to say global idexpression Mach *m.
> > I don't
> > remember if that is in the current release or in the upcoming
> > one.
> >
> > julia
> >
> >
> >
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