#!/bin/sh

# "When we build software, it's a good idea to have a reliable method
# for getting an executable from it. We want any two reconstructions
# starting from the same source to end up in the same result. That's
# just a basic intellectual premise."
#     -- Christian Quinnec, in _Lisp In Small Pieces_, p. 313

# This software is part of the SBCL system. See the README file for
# more information.
#
# This software is derived from the CMU CL system, which was
# written at Carnegie Mellon University and released into the
# public domain. The software is in the public domain and is
# provided with absolutely no warranty. See the COPYING and CREDITS
# files for more information.

# The value of SBCL_XC_HOST should be a command to invoke the
# cross-compilation Lisp system in such a way that it reads commands
# from standard input, and terminates when it reaches end of file on
# standard input. Suitable values are:
#   "sbcl"        to use an existing SBCL binary as a cross-compilation host
#   "sbcl --sysinit /dev/null --userinit /dev/null"
#                 to use an existing SBCL binary as a cross-compilation host
#                 even though you have stuff in your initialization files
#                 which makes it behave in such a non-standard way that
#                 it keeps the build from working
#   "lisp -batch" to use an existing CMU CL binary as a cross-compilation host
#   "lisp -noinit -batch" 
#                 to use an existing CMU CL binary as a cross-compilation host
#                 when you have weird things in your .cmucl-init file
#
# FIXME: Make a more sophisticated command line parser, probably
# accepting "sh make.sh --xc-host foolisp" instead of the
# the present "sh make.sh foolisp".
# FIXME: Tweak this script, and the rest of the system, to support
# a second bootstrapping pass in which the cross-compilation host is
# known to be SBCL itself, so that the cross-compiler can do some
# optimizations (especially specializable arrays) that it doesn't
# know how to implement how in a portable way. (Or maybe that wouldn't
# require a second pass, just testing at build-the-cross-compiler time
# whether the cross-compilation host returns suitable values from 
# UPGRADED-ARRAY-ELEMENT-TYPE?)
export SBCL_XC_HOST="${1:-sbcl}"
echo //SBCL_XC_HOST=\"$SBCL_XC_HOST\"

# If you're cross-compiling, you should probably just walk through the
# make-config.sh script by hand doing the right thing on both the host
# and target machines.
sh make-config.sh || exit 1

# The foo-host-bar.sh scripts are run on the cross-compilation host,
# and the foo-target-bar.sh scripts are run on the target machine. In
# ordinary compilation, we just do these phases consecutively on the
# same machine, but if you wanted to cross-compile from one machine
# which supports Common Lisp to another which does not (yet) support
# Lisp, you could do something like this:
#   Create copies of the source tree on both host and target.
#   Create links from "target" to "x86" in "src/compiler/" and
#     in "src/assembly/", on both the host and the target. (That
#     would ordinarily be done by the make.sh code above; if we're
#     doing make.sh stuff by hand, we need to do this by hand, too.)
#   On the host system:
#     SBCL_XC_HOST=<whatever> sh make-host-1.sh
#   Copy src/runtime/sbcl.h from the host system to the target system.
#   On the target system:
#     sh make-target-1.sh
#   Copy src/runtime/sbcl.nm from the target system to the host system.
#   On the host system:
#     SBCL_XC_HOST=<whatever> sh make-host-2.sh
#   Copy output/cold-sbcl.core from the host system to the target system.
#   On the target system:
#     sh make-host-2.sh
sh make-host-1.sh   || exit 1
sh make-target-1.sh || exit 1
sh make-host-2.sh   || exit 1
sh make-target-2.sh || exit 1