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? 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 _______________________________________________ freebsd-toolchain@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-toolchain To unsubscribe, send any mail to "freebsd-toolchain-unsubscr...@freebsd.org"
