On Sat May 28 11, Alexander Best wrote: > On Sat May 28 11, Bruce Cran wrote: > > On Sat, May 28, 2011 at 06:23:26PM +0000, Alexander Best wrote: > > > > > > well i'm not an expert on this. but are we 100% sure that a kernel on > > > amd64 > > > compiled with -O2 frename-registers can be debugged the same way as one > > > with > > > -O? if that is the case: sure...-O2 is fine. ;) > > > > > > however i've often read messages - mostly by bruce evans - claiming that > > > anything greater than -O will in fact decrease a kernel's ability to be > > > debugged just as well as a kernel with -O. > > > > > > > The critical option when -O2 is used is -fno-omit-frame-pointers, since > > removing > > frame pointers makes debugging impossible (on i386). With -O2 code is moved > > around and > > removed, so debugging is more difficult, but can still provide useful > > information. > > how about making -fno-omit-frame-pointers mandatory for all builds with an > optimisation level higher than -O?
man this is confusing. why must the freebsd make skeleton be so complicated. :( it seems -fno-omit-frame-pointers gets set in sys/conf/Makefile.amd64 and sys/conf/Makefile.powerpc already. also for modules in sys/conf/kmod.mk. i guess somebody with a better in deth knowledge should investigate this matter. this is a bit too complicated for me. cheers. alex > > something like > > .if !empty(COPTFLAGS:M-O[234sz]) && empty(COPTFLAGS:M-fno-omit-frame-pointers) > COPTFLAGS+= -fno-omit-frame-pointers > .endif > > (-O4 and -Oz are clang specific, but it won't hurt having them in there) > > cheers. > alex > > > > > -- > > Bruce Cran > > -- > a13x -- a13x _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
