I do sympathize with the "the user said to do it" argument as that is in keeping with our approach elsewhere. IIRC, what Jeff had implemented does print out a warning if we override the flag, so this would only be a minor change that might help alert people to what is going on. I would also suggest an FAQ entry as well.
On Jul 27, 2010, at 4:08 PM, Barrett, Brian W wrote: > Ok, so there is some middle ground I would dislike but not hate enough to > object to. How about having a AC_MSG_WARN if we find -g in the > CFLAGS/CXXFLAGS on OS X version 10.4 or later? Users get educated, I can > still make executables that are debugabble for my weird environment, and this > thread can die. It's not perfect, but at least it seems to accomplish > everyone's goals. > > Brian > > On Jul 27, 2010, at 4:02 PM, Barrett, Brian W wrote: > >> Unfortunately, there really is no middle ground. THe only option is to ask >> Apple to fix -g to mean -gstabs on OS X. I'm cross compiling from one >> version to another, so running an executable won't work. Looking at the >> three or four ways that you can specify a target version won't work >> (especially since at least in 10.4, you could change them without command >> line or environment variables). >> >> Sorry, there's no middle ground - this patch broke a use case that used to >> work. I know you guys didn't know about -gstabs. That doesn't make it >> right to do evil things. >> >> Brian >> >> On Jul 27, 2010, at 3:47 PM, Ralph Castain wrote: >> >>> Can I offer a middle ground? I believe we have been burned enough with the >>> -g vs -gstabs situation on OSX that it merits defaulting "appropriately". >>> So... >>> >>> Can we detect if gstabs is actually supported by the OS vs the compiler? >>> >>> If not, can we add logic that checks the OS target version and "does the >>> right thing"? >>> >>> My concern here is that our users are no more informed than Jeff or I were, >>> and will almost certainly specify -g when what they really mean is "I want >>> a debuggable executable". Unfortunately, as we all know, that isn't what >>> you get on OSX once you hit 10.4 and above. >>> >>> >>> >>> On Jul 27, 2010, at 3:29 PM, Barrett, Brian W wrote: >>> >>>> On Jul 27, 2010, at 3:13 PM, Jeff Squyres wrote: >>>> >>>>> On Jul 27, 2010, at 5:02 PM, Barrett, Brian W wrote: >>>>> >>>>>> Yes, but say I'm using a custom built version of gcc that doesn't do >>>>>> -gstabs quite right. Now you've screwed me. >>>>> >>>>> The configure test checks to see if -gstabs+ is accepted by the compiler. >>>> >>>> Yes, but acceptance and usefulness are not the same thing. >>>> >>>> If the TARGET_VERSION is 10.3, the compiler will accept -gstabs, but the >>>> executable won't be debugable on 10.3, because 10.3 didn't use gstabs. So >>>> I really, really want -g and you've just prevented me from doing what I >>>> want. That's not just bad, it's awful. >>>> >>>>>> I'm a firm believer that our configure script should do what the user >>>>>> says, as exactly as possible. Changing AC behavior a little bit is a >>>>>> gray area, but one I'm almost ok with (since AC_PROG_CC will add -g if >>>>>> CFLAGS is empty). >>>>> >>>>> We override that, though -- we take out that -g if CFLAGS was empty. >>>>> >>>>> I understand what you're saying, and in general I agree -- that we should >>>>> add as little as possible to what the user said. But I don't quite know >>>>> how to balance: >>>>> >>>>> * adding as few flags as possible >>>>> * making debugging symbols work for those of us who aren't familiar >>>>> enough with OSX to know that you need the special/secret -gstabs+ flag >>>>> (and just expect -g to be enough) >>>>> >>>>> I've been developing POSIX software on a Mac for several years (i.e., not >>>>> Mac-specific software, so I never dived into the details of Mac-specific >>>>> functionality) and fell into the 2nd category until about a week ago. >>>>> >>>>> Got any suggestions? >>>> >>>> Yes, don't cause problems - if the user specified -g, assume he meant -g. >>>> I understand what you're saying, but I'm against changing what the user >>>> specified because we know better. We usually don't, and in this case, >>>> there are known use cases where that's true. >>>> >>>> Brian >>>> >>>> -- >>>> Brian W. Barrett >>>> Dept. 1423: Scalable System Software >>>> Sandia National Laboratories >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> devel mailing list >>>> de...@open-mpi.org >>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel >>> >>> >>> _______________________________________________ >>> devel mailing list >>> de...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/devel >>> >> >> -- >> Brian W. Barrett >> Dept. 1423: Scalable System Software >> Sandia National Laboratories >> >> >> > > -- > Brian W. Barrett > Dept. 1423: Scalable System Software > Sandia National Laboratories > > > > > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel
