Messages in this thread | | | Date | Tue, 30 Nov 2010 10:40:39 -0800 | From | Michael Snyder <> | Subject | Re: [PATCH] Built kernel without -O2 option |
| |
Américo Wang wrote: > On Mon, Nov 29, 2010 at 11:12:16AM +0100, Mark Wielaard wrote: >> On Mon, 2010-11-29 at 10:59 +0100, Andi Kleen wrote: >>> Hui Zhu <teawater@gmail.com> writes: >>> >>>> Now, there are a lot of ways to debug the Linux kernel with GDB, like >>>> qemu, kgtp or kgdb and so on. >>>> But the developer more like add a printk. It have a lot of reason, a big one is: >>>> (gdb) p ret >>>> $3 = <value optimized out> >>>> And the code execution order is not right. >>> Really the right place to fix a lot of this would be gcc (and perhaps >>> gdb). I suspect with some careful work the debugging experience >>> for -O2 could be improved a lot. >>> I also believe the latest gccs already have improvements in this area. >> The VTA branch was merged for GCC 4.5 >> http://gcc.gnu.org/wiki/Var_Tracking_Assignments >> Which helps a lot with generating dwarf for previously "optimized out" >> values. There were also a couple of papers on generating even better >> debuginfo at the recent GCC Summit: http://gcc.gnu.org/wiki/summit2010 >> >> Jakub Jelínek, Improving debug info for optimized away parameters >> http://gcc.gnu.org/wiki/summit2010?action=AttachFile&do=get&target=jelinek.pdf >> Alexandre Oliva, Consistent Views at Recommended Breakpoints >> http://gcc.gnu.org/wiki/summit2010?action=AttachFile&do=get&target=oliva.pdf >> > > Cool! It would be much more convenient if this is solved by gcc.
Those features mentioned at the GCC summit are not real close to completion. I wouldn't put off the discussion just because they're (possibly) in the pipeline.
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |