7+ days of dogfood
bf1783 at googlemail.com
Wed Feb 13 04:02:43 UTC 2013
On 2/13/13, Steve Kargl <sgk at troutmask.apl.washington.edu> wrote:
> On Wed, Feb 13, 2013 at 02:15:08AM +0000, b.f. wrote:
>> On 2/13/13, Steve Kargl <sgk at troutmask.apl.washington.edu> wrote:
>> > On Wed, Feb 13, 2013 at 12:18:29AM +0000, b.f. wrote:
>> >> ># cat /etc/make.conf|grep FFLAGS
>> >> >FFLAGS = -O2 -pipe -march=native -mtune=native
>> >> Please do _not_ assign flags unconditionally in make.conf.
>> > FFLAGS is for compiling Fortran. I'm one of the people who
>> > has spent years working/patching gfortran. I think I might
>> > have a better understanding of what options to use with
>> > gfortran than most people.
>> I know you have, but you are giving advice that is liable to be abused
>> by those who are less experienced. The flags you are adding are not
>> the problem -- it's the way that you are adding them -- specifically,
>> the assignment in the first line of your snippet, if it's applied
>> unconditionally. You should either be appending all of them, or
>> assigning them conditionally, so that they are sure to be assigned
>> only once, or -- preferably -- using another makefile that can't be
>> re-read multiple times during a build (ports/Mk/bsd.port.mk
>> automatically includes several makefiles that can be used for this
>> purpose, if you are building a port). You have been lucky not to trip
>> over this: every couple of months for the last several years I have
>> had to debug errors reported by users that arise from this problem. It
>> is more common with CFLAGS and CXXFLAGS but it can happen with FFLAGS,
> Try 'find /usr/ports -name Makefile -maxdepth 3 | xargs grep FFLAGS'
> Then go read about the options chosen by the various port maintainers.
> I specifically set FFLAGS to avoid the questionable options set in
> the ports. If -malign-double appears in a port, it should probably
> be marked as broken. If a port uses -fdefault-real-8, it should probably
> be marked as broken. If a port uses -ffast-math, it may have issues that
> are extremely difficult to debug.
Okay, so you are doing this advisedly for some specific subset of
ports, and have the knowledge to debug problems that may arise --
others don't. Undoubtedly some of these additions are suboptimal or
unnecessary -- and I'm sure we'd welcome patches or suggestions to
improve them -- but there are also important additions like the rpath
flags in $PORTSDIR/Mk/bsd.gcc.mk or mangling and PIC directives. And
not all of the additions are in the ports tree makefiles or
patchfiles: many software distribution makefiles also make additions
that can be clobbered by abusing make.conf.
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