* Tom Tromey ([email protected]) wrote: > >>>>> "Dexuan" == Cui, Dexuan <[email protected]> writes: > > Mathieu> Also, we should reopen the discussion on the way the UST Markers > Mathieu> collect the registers for GDB, because the current way involves a > Mathieu> _lot_ of ugly assembly code. It should be possible to only use a > Mathieu> volatile inline asm to specify input constraints on the target marker > Mathieu> parameters, and keep the instruction pointer address that corresponds > Mathieu> to this inline asm in a section known by gdb (so gdb could use the > Mathieu> drawf info to fetch data from registers/memory). If you can ensure > Mathieu> that this would fit gdb's requirements, I could clean up the marker > Mathieu> code and we could resync the APIs together. We could also provide > Mathieu> this for UST Tracepoints in the same go, with pretty much the same > Mathieu> interface as we'd use for UST Markers. I am aware that this would > Mathieu> require change on the GDB side, but I think it's better to > Mathieu> synchronise our effort rather than to shoot at different targets. > > I am not totally clear on the proposal here. > > If this means reusing the <sys/sdt.h> stuff, then there are gdb patches > already submitted to fully support that; and updating the existing code > to also use it should not be very difficult. See gdb-patches from the > last month or two.
Yes, the goal is to rely on sdt.h as soon as it supports a e.g. STAP_PROBEV (with variable number of args). The Josh Stone found a neat trick to do it, and I think he is preparing an updated version. The only concern here is the packaging: if we depend on sdt.h, we have to either ship it with UST, or have one more dependency on a package available for all architectures that only contain this header. Thoughts ? It's good to hear that GDB is already planning on supporting that. Thanks, Mathieu > > If instead you mean something else, it would be useful to have more > information. From your description it sounds like this may be a > different design from SDT v3; but note that SDT v2 tried to use DWARF to > access the parameters and ran into various problems. I can get details > on the failure modes if this is what you intend. > > Dexuan> Unluckily I'm pretty new to gdb and know few about this now. > Dexuan> Let me Cc the gdb mailing list for more thoughts(hope this > cross-posting > Dexuan> wouldn't bother people). > > Cross-posting in cases like this is fine, even preferable. > > I don't know anything about the gdbserver bits here. It seems to me > that it would be reasonable to have gdbserver compile against various > versions of UST. > > Tom > -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
