Thanks to the work of Gary Benson on implementing and merging the Zero-Assembler Project, and Greg Lewis' work bringing it to OpenJDK BSD Port, it's now possible to bootstrap OpenJDK 7 on Mac OS X 10.5/PPC.
Gary Benson's Zero Assembler provides a portable implementation of the JVM intepreter that -- unlike the existing JVM implementations -- relies on very little assembler to provide an acceptably performing but highly portable VM, opening the door to supporting Mac OS X PPC with very little additional work.
I've committed the few small fixes to get OpenJDK running on Mac OS X 10.5/PPC, and have bootstrapped an initial OpenJDK 7 binary using Havard Eidnes's bootstrap scripts. Bootstrapping the initial VM running is sufficiently involved that I would recommend using my binaries (openjdk7-macppc-2009-12-16-b4.tar.bz2).
OpenJDK uses Mercurial with the Forest extension. Before checking out the BSD sources, you will need to install and configure Mercurial. See the OpenJDK Developer's Guide for more information.
To check out the BSD-Port forest:
hg fclone http://hg.openjdk.java.net/bsd-port/bsd-port
Building OpenJDK requires Java 6 or OpenJDK 7 -- on PPC, you will need to download or build an OpenJDK 7 bootstrap VM (openjdk7-macppc-2009-12-16-b4.tar.bz2).
To build the JDK in build/bsd-ppc/j2sdk-image:
make \ CC=gcc-4.0 \ CXX=g++-4.0 \ ALT_BOOTDIR=/usr/local/openjdk7-macppc-2009-12-16-b4 ANT_HOME=/usr/share/ant \ ALT_FREETYPE_HEADERS_PATH=/usr/X11/include \ ALT_FREETYPE_LIB_PATH=/usr/X11/lib \ ALT_CUPS_HEADERS_PATH=/usr/include \ ALT_CACERTS_FILE=/System/Library/Frameworks/JavaVM.framework/Home/lib/security/cacerts \ LIBFFI_CFLAGS="-I/usr/include/ffi" \ NO_DOCS=true \ ZERO_BUILD=true \ ZERO_ENDIANNESS=big \ ZERO_LIBARCH=ppc \ ZERO_ARCHDEF=PPC \ ZERO_ARCHFLAG=-m32
Be sure to set ALT_BOOTDIR to the path of your installed openjdk7-macppc-2009-12-16-b4 bootstrap JDK.
Once built, you should now have a JDK in build/bsd-ppc/j2sdk-image:
landonf@onefish:~/openjdk-ppc/bsd-port> ./build/bsd-ppc/j2sdk-image/bin/java -version openjdk version "1.7.0-internal" OpenJDK Runtime Environment (build 1.7.0-internal-landonf_2009_12_16_12_54-b00) OpenJDK Zero VM (build 17.0-b05, interpreted mode)
For more information or assistance, please refer to the OpenJDK BSD-Port wiki and mailing list. My testing has been very limited -- if you run into issues, please report them on the development mailing list.