Safe reversion to older version of C compiler

jkeenan1 has asked for the wisdom of the Perl Monks concerning the following question:

I have been advised to, for certain purposes, revert to an older version of my C compiler and I would like advice on how to do so safely.

I have a 2-1/2 year old iBook which I have upgraded from Mac OS X 10.3 to 10.4.8; the kernel is now Darwin 8.8.0. As best as I can determine, the C compiler that came when I installed Developer Tools was Apple's build 1495 of gcc version 3.3.

lrwxr-xr-x   1 root  wheel       7 Aug  9  2004 /usr/bin/cc -> gcc-3.3
lrwxr-xr-x   1 root  wheel       7 Aug  9  2004 /usr/bin/gcc -> gcc-3.
+3

[bin] 524 $ gcc-3.3 -v
Reading specs from /usr/libexec/gcc/darwin/ppc/3.3/specs
Thread model: posix
gcc version 3.3 20030304 (Apple Computer, Inc. build 1495)
[download]

In April of this year, in an abortive attempt to install a Perl module that needed the GMP library, I decided to upgrade to the most recent version of gcc that would build on my box and to build that from source. After much sweat, I succeeded, in the process installing a considerable volume of software. Here's the partial output from ls -l /usr/local/bin.

-rwxr-xr-x   1 root  jimk    226144 Apr 15  2006 grepjar
-rwxr-xr-x   1 root  jimk    197460 Apr 15  2006 fastjar
-rwxr-xr-x   2 root  jimk    331868 Apr 15  2006 powerpc-apple-darwin7
+.9.0-gcjh
-rwxr-xr-x   2 root  jimk    340676 Apr 15  2006 powerpc-apple-darwin7
+.9.0-gcj
-rwxr-xr-x   4 root  jimk    331168 Apr 15  2006 powerpc-apple-darwin7
+.9.0-g++
-rwxr-xr-x   4 root  jimk    331168 Apr 15  2006 powerpc-apple-darwin7
+.9.0-c++
-rwxr-xr-x   2 root  jimk    331868 Apr 15  2006 gcjh
-rwxr-xr-x   2 root  jimk    340676 Apr 15  2006 gcj
-rwxr-xr-x   4 root  jimk    331168 Apr 15  2006 g++
-rwxr-xr-x   4 root  jimk    331168 Apr 15  2006 c++
-rwxr-xr-x   1 root  jimk    233400 Apr 15  2006 jv-scan
-rwxr-xr-x   1 root  jimk    335736 Apr 15  2006 jcf-dump
-rwxr-xr-x   1 root  jimk    331868 Apr 15  2006 gjnih
-rwxr-xr-x   1 root  jimk    176124 Apr 15  2006 gcov
-rwxr-xr-x   1 root  jimk     15683 Apr 15  2006 gccbug
-rwxr-xr-x   1 root  jimk    330788 Apr 15  2006 cpp
-rwxr-xr-x   3 root  jimk    329764 Apr 15  2006 powerpc-apple-darwin7
+.9.0-gcc-4.0.3
-rwxr-xr-x   3 root  jimk    329764 Apr 15  2006 powerpc-apple-darwin7
+.9.0-gcc
-rwxr-xr-x   3 root  jimk    329764 Apr 15  2006 gcc
-rwxr-xr-x   1 root  jimk     12272 Apr 15  2006 jv-convert
-rwxr-xr-x   1 root  jimk     11512 Apr 15  2006 gij
-rwxr-xr-x   1 root  jimk     12284 Apr 15  2006 grmiregistry
-rwxr-xr-x   1 root  jimk     12272 Apr 15  2006 grmic
-rwxr-xr-x   1 root  jimk    171768 Apr 15  2006 gcj-dbtool
-rwxr-xr-x   1 root  jimk      1022 Apr 15  2006 addr2name.awk
[download]

So now, gcc 4.0.3 appears to my system to be the default C compiler.

[jimk] 535 $ ls -l `which gcc`
-rwxr-xr-x   3 root  jimk  329764 Apr 15  2006 /usr/local/bin/gcc
[jimk] 536 $ gcc -v
Using built-in specs.
Target: powerpc-apple-darwin7.9.0
Configured with: ../gcc-4.0.3/configure  : (reconfigured) ../gcc-4.0.3
+/configure 
Thread model: posix
gcc version 4.0.3
[download]

For several months, this had no particular impact on the operation of my system. In particular, several months later I was able to upgrade Perl from source. That upgrade used version 3.3 of gcc rather than the more recently installed 4.0.3.

Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
  Platform:
    osname=darwin, osvers=8.7.0, archname=darwin-2level
    uname='darwin macintosh.local 8.7.0 darwin kernel version 8.7.0: f
+ri may 26 15:20:53 pdt 2006; root:xnu-792.6.76.obj~1release_ppc power
+ macintosh powerpc '
    config_args='-de'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultipl
+icity=undef
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-common -DPERL_DARWIN -no-cpp-precomp -fno-
+strict-aliasing -pipe -I/usr/local/include',
    optimize='-O3',
    cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN -no-cpp-precom
+p -fno-strict-aliasing -pipe -I/usr/local/include'
    ccversion='', gccversion='3.3 20030304 (Apple Computer, Inc. build
+ 1495)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=4321
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=8
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
+ lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -L/usr/local
+/lib'
    libpth=/usr/local/lib /usr/lib
    libs=-ldbm -ldl -lm -lc
    perllibs=-ldl -lm -lc
    libc=/usr/lib/libc.dylib, so=dylib, useshrplib=false, libperl=libp
+erl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/u
+sr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: PERL_MALLOC_WRAP USE_LARGE_FILES USE_PERLIO
  Built under darwin
  Compiled at Sep 13 2006 20:15:49
  @INC:
    /usr/local/lib/perl5/5.8.8/darwin-2level
    /usr/local/lib/perl5/5.8.8
    /usr/local/lib/perl5/site_perl/5.8.8/darwin-2level
    /usr/local/lib/perl5/site_perl/5.8.8
    /usr/local/lib/perl5/site_perl/5.8.7/darwin-2level
    /usr/local/lib/perl5/site_perl/5.8.7
    /usr/local/lib/perl5/site_perl/5.8.4/darwin-2level
    /usr/local/lib/perl5/site_perl/5.8.4
    /usr/local/lib/perl5/site_perl
    .
[download]

In November, however, I started to work on the Parrot project. I encountered considerable difficulties in getting Parrot to make properly. Some of these were problems with Parrot, and I got considerable help from Parrot hackers at the Chicago Perl Hackathon and on #parrot in working around these.

But I'm still having trouble getting Parrot to make. Several experienced Parrot hackers report that they have no problem building Parrot on Mac OS X and that they use the gcc version 3.3 that came with the Mac. They have advised me to revert to that version. How can I do so safely? Specifically:

Would it be as simple as saying cc=/usr/bin/gcc when I run Parrot's Configure.pl?
Or do I need to take more drastic steps, such as:
- Creating symlinks in /usr/local/bin which point back to the older version of gcc in /usr/bin; or
- Trying to uninstall the gcc 4.0.1 I installed in April?

Thanks for reading this far.

Comment on Safe reversion to older version of C compiler Select or Download Code

Replies are listed 'Best First'.
Re: Safe reversion to older version of C compiler by chargrill (Parson) on Dec 17, 2006 at 16:47 UTC
Hi, check out the utility that ought to have been installed (at least when you have the Mac Dev Tools installed) called `gcc_select`. Here's a short snippet from it's man page: `GCC_SELECT(8) MacOS X GCC_SELECT(8) SYNOPSIS gcc_select -- Switch the default system compiler USAGE gcc_select [-n] [-force] [2 \| 3 \| 3.<number> \| 4.<number> ] [-h \| --help] [-v \| --version] [-l \| --list] [-root] o 2: Select gcc 2.95.2 as the default compiler. o 3: Select gcc 3.1 as the default compiler. o 3.x: Select gcc 3.x as the default compiler. o 4.x: Select gcc 4.x as the default compiler.` [download] --chargrill `s*lil; $=join'',sort split q; s;.;grr; &&s+(.(.)).+$2$1+; $; = qq-$_-;s,.,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$,$/)` [download]	[reply] [d/l] [select]
Re^2: Safe reversion to older version of C compiler by jkeenan1 (Deacon) on Dec 17, 2006 at 17:17 UTC
Thanks for your response! After my OP, I pulled the coat of Parrot hacker Coke to it. We discussed it a bit on #parrot and he advised me to first (do no harm) and try running Parrot's Configure.pl script with some shell variables re-set. Incorporating an earlier suggestion from Parrot hacker particle, this is what I came up with: `#!/bin/sh CC="/usr/bin/gcc-3.3" CX="/usr/bin/g++-3.3" /usr/local/bin/perl Configure.pl --cc="$CC" --cxx="$CX" --link="$CX" - +-ld="$CX" --without-icu --without-gmp $@` [download] ... which kinda does what gcc_select would do. This script resulted in a Parrot configuration which you can see here. make ran without a hitch! And make test (probably as a result of yesterday's on-line Parrot Bug Day) ran with only 1 failing test -- down from 62 the last time I tried that a couple of weeks ago. Jim Keenan	[reply] [d/l]
Re^3: Safe reversion to older version of C compiler by chargrill (Parson) on Dec 17, 2006 at 17:24 UTC
I'm glad you got it working one way or another. Too bad I had to miss the hackathon in (greater) Chicago in November (due to some scheduling conflicts). Maybe I could've helped eliminate your frustration a little earlier :) I don't recall where/why/how I first read about the `gcc_select` utility, but I suppose it's good that it's recorded above for anyone else who might be looking for it :) --chargrill `s*lil; $=join'',sort split q; s;.;grr; &&s+(.(.)).+$2$1+; $; = qq-$_-;s,.,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$,$/)` [download]	[reply] [d/l] [select]