Re: Bountysource campaign for gcc-vax

["Maciej W. Rozycki" <macro%orcam.me.uk@localhost>]

On Sun, 2 May 2021, Martin Husemann wrote:

> One option is to build a cross toolchain via the standard gcc procedure
> on the build machine, targetting VAX. Then copy over all created binaries
> (e.g. to /usr/local/) and play with them manually to verify they work for
> simple programs. When that works, set CC (and maybe AS, LD, ...) in the
> environment and build a kernel (this still works the old way, with config
> and make, you may have to additionally set USE_TOOLS=never).

 Umm, not targetting, but hosting VAX (i.e. cross-build native GCC).  As I 
noted previously you need to do that in three steps on your non-VAX system 
(I suggest choosing a mighty one as otherwise it'll take a while, and make 
sure you run parallel builds if SMP):

1. Build native GCC 11, e.g.:

$ cd /path/to/gcc-src
$ contrib/download_prerequisites
$ mkdir -p $HOME/vax/native-gcc
$ cd $HOME/vax/native-gcc
$ /path/to/gcc-src/configure --disable-nls \
	--disable-version-specific-runtime-libs --enable-languages=c,c++ \
	--prefix=/usr
$ gmake -j 64 bootstrap
$ gmake DESTDIR=$HOME/vax/install install

2. Install VAX headers and libraries in the intended sysroot, e.g.:

$ mkdir -p $HOME/vax/install/usr/sysroot
$ cd $HOME/vax/install/usr/sysroot
$ ssh vax 'tar -ch lib/libc.so* lib/libm.so* libpthread.so* 
	libexec/ld.elf_so usr/include usr/lib/*crt?.o 
	usr/lib/lib[cm][._]* usr/lib/libposix[._]* 
	usr/lib/libpthread[._]* usr/libexec/ld.elf_so' | tar -xp

(this needs to dereference symlinks as some are absolute and therefore 
won't work when copied over; you can recreate them as relative ones by 
hand instead if you so prefer).

3. Build VAX binutils 2.36.1 and GCC 11 (using the newly-built native
   compiler), e.g.:

$ export PATH=$HOME/vax/install/bin:$PATH
$ export LD_LIBRARY_PATH=$HOME/vax/install/lib
$ mkdir -p $HOME/vax/vax-binutils
$ cd $HOME/vax/vax-binutils
$ /path/to/binutils-src/configure --disable-gdb --disable-gdbserver \
	--disable-libdecnumber --disable-readline --disable-sim \
	--with-sysroot=/usr/sysroot --target=vax-netbsdelf
$ gmake -j 64
$ gmake DESTDIR=$HOME/vax/install install
$ mkdir -p $HOME/vax/vax-gcc
$ cd $HOME/vax/vax-gcc
$ /path/to/gcc-src/configure --disable-nls \
	--disable-version-specific-runtime-libs --enable-languages=c,c++ \
	--with-build-sysroot=$HOME/vax/install/usr/sysroot \
	--with-sysroot=/usr/sysroot --prefix=/usr \
	--with-toolexeclibdir=/usr/sysroot/usr/lib --target=vax-netbsdelf
$ gmake -j 64
$ gmake DESTDIR=$HOME/vax/install install

4. Build native VAX GCC 11 (using the newly-built VAX binutils and GCC), 
   e.g.:

$ export PATH=$HOME/vax/install/bin:$PATH
$ export LD_LIBRARY_PATH=$HOME/vax/install/lib
$ mkdir -p $HOME/vax/vax-native-gcc
$ cd $HOME/vax/vax-native-gcc
$ /path/to/gcc-src/configure --disable-nls \
	--disable-version-specific-runtime-libs --enable-languages=c,c++ \
	--prefix=/usr --host=vax-netbsdelf
$ gmake -j 64
$ gmake DESTDIR=$HOME/vax/install/usr/sysroot install

5. And then either copy $HOME/vax/install/usr/sysroot over to your VAX 
   system somewhere or just export the directory over NFS as I previously 
   suggested (in which case you won't ever get caught by using a stale 
   copy by accident as you iterate over the process).

Substitute `64' with the number of processors in the non-VAX machine (for 
Linux I use `$(nproc)', but I don't know what's the NetBSD's equivalent), 
and `$HOME/vax' with whatever is convenient.  Apologies for any bash-isms 
above (hopefully trivially resolved), and if anything above does not work 
right away and tweaks are required (hopefully minor).

 NB it could be easier and maybe more reliable to set PATH on the VAX 
system so that the new tools are found first rather than tweaking CC, CXX, 
etc. individually.  I'd normally only override CC, CXX, etc. if options 
are required to configure the compilation correctly, such as to select a 
non-default multilib (ordinary user flags go into CFLAGS, CXXFLAGS, etc.).

 HTH,

  Maciej