On Mon, Feb 04, 2013 at 09:22:27AM -0500, Jack Howarth wrote:
> On Mon, Feb 04, 2013 at 10:38:29AM +0100, Jakub Jelinek wrote:
> > On Mon, Feb 04, 2013 at 10:22:48AM +0100, Richard Biener wrote:
> > > > Okay for gcc trunk?
> > >
> > > But that does not work across translation units, no? ISTR collect2 has
> > > support
> > > to handle constructor priorities all by itself (at link time,
> > > considering all inputs).
> >
> > I wonder why the patch turned from initially at least supporting intra-CU
> > support for ctor priorities into an ugly hack for asan. I guess asan
> > doesn't care too much about inter-CU ctor priorities, it just needs its
> > ctors to run before anything in the same CU is called (mainly the
> > __asan_init call), other CUs either won't be asan instrumented, then it
> > doesn't matter, or will be, but they will have their own __asan_init call.
>
> Jakub,
> I switched to the simple insertion of the asan priorities for two
> reasons...
>
> 1) Mike seemed unconvinced that the single qsort with the proposed
> sort_ctor_records
> of...
>
> +static int
> +sort_ctor_records (const void * a, const void * b)
> +{
> + const ctor_record *ca = (const ctor_record *)a;
> + const ctor_record *cb = (const ctor_record *)b;
> + if (ca->priority > cb->priority)
> + return 1;
> + if (ca->priority < cb->priority)
> + return -1;
> + if (ca->position > cb->position)
> + return -1;
> + if (ca->position < cb->position)
> + return 1;
> + return 0;
> +}
>
> would really be stable in absence of a second call to qsort.
>
> 2) Once I realized that darwin sets the default priority of constructors to
> DEFAULT_INIT_PRIORITY 65535, the desired sorting method seemed rather unclear.
> I assume we need to really sort these so that the priorities from
> MAX_INIT_PRIORITY-1 through 0 appear first in the queue and then those with
> MAX_INIT_PRIORITY, right? It isn't obvious how we can achieve that in
> sort_ctor_record with a single pass through qsort.
> Jack
Nevermind. I now see sorting priorities from lower to higher throughout is
correct. I'll
repost the originally proposed patch for qsort later.
Jack
>
> >
> > > I wonder why darwin cannot use that mechanism to support init priorities?
> >
> > But sure, if collect2 can be used for full init prio support, the better.
> >
> > Jakub
