Date: Mon, 9 Jan 2012 21:21:35 -0500 From: Wesley Shields <wxs@FreeBSD.org> To: bf1783@gmail.com Cc: gerald@FreeBSD.org, freebsd-ports@FreeBSD.org Subject: Re: USE_GCC and CC=clang Message-ID: <20120110022135.GA6493@atarininja.org> In-Reply-To: <CAGFTUwNtxN6yLtML9LXhoedjA=Xc0uM9dDOeoF0PhATE11Tskw@mail.gmail.com> References: <CAGFTUwNtxN6yLtML9LXhoedjA=Xc0uM9dDOeoF0PhATE11Tskw@mail.gmail.com>
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On Mon, Jan 09, 2012 at 06:22:58PM +0000, b. f. wrote: > > I'm trying to fix a port which absolutely will not build with clang, > > since clang does not support the gcc extension used by this port. I set > > USE_GCC=4.2+, which is the lowest version of GCC which will work, but it > > doesn't properly override CC=clang. > > > > wxs at ack spamdyke % env CC=clang make test-gcc | grep -E "^(CC|USE_GCC)" > > USE_GCC=4.2+ > > CC=clang - CXX=c++ - CPP=cpp - CFLAGS="-O2 -pipe -fno-strict-aliasing" > > wxs at ack spamdyke % > > > > This problem only arises if the base compiler is gcc 4.2.x and > USE_GCC=4.2+. Otherwise CC will be set to the appropriate gcc > compiler. Since Gerald (who maintains ports/Mk/bsd.gcc.mk) is trying > to retire lang/gcc42 anyway, it is not a good idea to set USE_GCC=4.2+ > in a port. Thanks for the pointer. > > I understand this is probably an acceptable behavior, since if the user > > sets CC=clang they are explicitly asking to build with clang. However, > > in the case of a port known to not work with clang, and more importantly > > not able to be fixed, I was hoping there was a knob I could set that > > would forcible override any compiler related environment variables which > > may be set. I didn't find one, so I came up with this quick (and poorly > > tested) patch to do so. > > The problem is due to a slight flaw in the implementation of the > USE_GCC=4.2+ case, which will be obviated soon by the removal of this > case. If in the meantime a change is made to bsd.gcc.mk, it should > address this flaw directly -- by setting CC=gcc explicitly where > needed, instead of relying upon the default setting of CC. Another > knob is unnecessary. > > Note that changes to bsd.gcc.mk, good or bad, won't address the cases > where a user sets CC on the command-line via "make .... CC= ...", or > adds it to MAKE_ARGS, or sets CC in the environment, and then calls > make with "-e" or "-E CC". So the right thing to do is to add > something like: > > .if !empty(CC:M*clang*) > IGNORE= : clang cannot be used to build this port > .endif > > to the port Makefile, after the inclusion of bsd.port.options.mk or > bsd.port.pre.mk (since a user may have set CC in Makefile.local, > Makefile.inc, etc). Or, better yet, to patch the port so that it can > be built with clang (which may have to be done anyway...). I was hoping to not have to set IGNORE if using clang. I'm also not really interested in patching the port, since it's more about structural changes than a simple fixes. I guess I'll set the IGNORE line if using clang for now. No point in wasting cycles on a port which won't compile for a long time, if ever. -- WXS
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