On Sun, Dec 15, 2013 at 02:30:14PM +0000, Nicholas Clark wrote:
> I hacked up (somewhat literally) the attached 3 patches, to try to help
> automate GC debugging for MoarVM. The intent is to be able to change how
Next mole to whack:
$ gdb --args /home/nicholas/Sandpit/moar-g/bin/moar nqp.moarvm t/nqp/56-role.t
...
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff79e4752 in MVM_gc_collect_free_stables (tc=0x6023f0)
at src/gc/collect.c:555
555 st = (MVMSTable *)st_to_free->header.forwarder;
Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.107.el6.x86_64
(gdb) where
#0 0x00007ffff79e4752 in MVM_gc_collect_free_stables (tc=0x6023f0)
at src/gc/collect.c:555
#1 0x00007ffff79dc666 in MVM_gc_enter_from_allocator (tc=0x6023f0)
at src/gc/orchestrate.c:373
#2 0x00007ffff79dc83a in MVM_gc_allocate_nursery (tc=0x6023f0, size=40)
at src/gc/allocation.c:32
#3 0x00007ffff79dc8bf in MVM_gc_allocate_zeroed (tc=0x6023f0, size=40)
at src/gc/allocation.c:49
#4 0x00007ffff79dcb02 in MVM_gc_allocate_object (tc=0x6023f0, st=0x603360)
at src/gc/allocation.c:85
#5 0x00007ffff79fcc73 in allocate (tc=0x6023f0, st=0x603360)
at src/6model/reprs/P6int.c:22
#6 0x00007ffff79a5998 in MVM_interp_run (tc=0x6023f0,
initial_invoke=0x7ffff7a2faaf <toplevel_initial_invoke>,
invoke_data=0x750000) at src/core/interp.c:2268
#7 0x00007ffff7a2fbdc in MVM_vm_run_file (instance=0x602010,
filename=0x7fffffffe826 "nqp.moarvm") at src/moar.c:157
#8 0x0000000000400d2e in main (argc=3, argv=0x7fffffffe5a8) at src/main.c:137
(gdb) p st_to_free
$1 = (MVMSTable *) 0x7ffff6a3a3c0(gdb) p st_to_free->header
$2 = {owner = 0, flags = 2, size = 168, forwarder = 0x0, sc = 0x0}
(gdb) p st_to_free
$3 = (MVMSTable *) 0x7ffff6a3a3c0
(gdb) p tc->nursery_fromspace
$4 = (void *) 0x7ffff6892000
(gdb) p tc->nursery_tospace
$5 = (void *) 0x7ffff6a92000
So that's st_to_free in fromspace. Presumably it's the STABLE(type) here:
OP(box_i): {
MVMObject *type = GET_REG(cur_op, 4).o;
MVMObject *box = REPR(type)->allocate(tc, STABLE(type));
MVMROOT(tc, box, {
if (REPR(box)->initialize)
REPR(box)->initialize(tc, STABLE(box), box,
OBJECT_BODY(box));
REPR(box)->box_funcs.set_int(tc, STABLE(box), box,
OBJECT_BODY(box), GET_REG(cur_op, 2).i64);
GET_REG(cur_op, 0).o = box;
});
cur_op += 6;
goto NEXT;
}
(Again) I don't know what the correct fix is.
Nicholas Clark
