Re: [Help-smalltalk] GST segfaults when running under GDB

[Holger Hans Peter Freyther]

On Sat, Feb 28, 2015 at 02:42:27PM +0000, Jan Vrany wrote:
> Hi, 

Hi!

> Is it normal? If so, do I have to setup GDB specially or
> compile GST specially to be able to debug it?

Yes that is normal. For the incremental/generational garbage
collection one needs to know which objects changed since the
last operation. The classic way is to have a read/write barrier
(e.g. keep track everytime a pointer is followed to another
object). The approach Paolo picked was to use mprotect on the
pages the object is allocated.

This means that a SIGSEGV will be generated on these objects
and the garbage collector remembers it.

a.) In gdb you can do:

handle SIGSEGV nostop noprint
b abort
b exit

b.) You can compile GST with another GC and/or in libgst/oop.h
force "NO_SIGSEGV_HANDLING"