| Things libgcj hackers should know |
| --------------------------------- |
| |
| If you want to hack on the libgcj files you need to be aware of the |
| following things. There are probably lots of other things that should be |
| explained in this HACKING file. Please add them if you discover them :) |
| |
| -- |
| |
| libgcj uses GNU Classpath as an upstream provider. Snapshots of |
| Classpath are imported into the libgcj source tree. Some classes are |
| overridden by local versions; these files still appear in the libgcj |
| tree. |
| |
| To import a new release: |
| |
| - Check out a classpath snapshot |
| I use 'cvs export' for this. Make a tag to ensure future hackers |
| know exactly what revision was checked out; tags are of the form |
| 'libgcj-import-DATE'. |
| - Use auto* to create configure, Makefile.in, etc |
| You have to make sure to use the gcc libtool.m4 and gcc lt* scripts |
| cd .../classpath |
| cp ../../lt* . |
| cp ../../config.sub ../../config.guess . |
| aclocal -I m4 -I ../.. |
| autoconf |
| autoheader |
| automake |
| rm -rf autom4te.cache |
| - Test everything first. The simplest way to do this is by overlaying |
| the checked out classpath on your gcc tree and then doing a build. |
| - Use 'cvs import' to import. The vendor tag is 'CLASSPATH'. For the |
| release tag, if this is a released classpath version, use something |
| like 'classpath-import-VERSION'; otherwise something like |
| 'classpath-import-DATE'. |
| Be sure to use -ko and -I\! |
| - Remove any files that were deleted in Classpath |
| - Run 'scripts/makemake.tcl > sources.am' in the source tree |
| - Run automake for libgcj |
| |
| Over time we plan to remove as many of the remaining divergences as |
| possible. |
| |
| File additions and deletions require running scripts/makemake.tcl |
| before running automake. |
| |
| -- |
| |
| In general you should not make any changes in the classpath/ |
| directory. Changes here should come via imports from upstream. |
| However, there are two (known) exceptions to this rule: |
| |
| * In an emergency, such as a bootstrap breakage, it is ok to commit a |
| patch provided that the problem is resolved (by fixing a compiler |
| bug or fixing the Classpath bug upstream) somehow and the resolution |
| is later checked in (erasing the local diff). |
| |
| * On a release branch to fix a bug, where a full-scale import of |
| Classpath is not advisable. |
| |
| -- |
| |
| You can develop in a GCC tree using a CVS checkout of Classpath, most |
| of the time. (The exceptions are when an incompatible change has been |
| made in Classpath and some core part of libgcj has not yet been |
| updated.) |
| |
| The way to set this up is very similar to importing a new version of |
| Classpath into the libgcj tree. In your working tree: |
| |
| * cd gcc/libjava; rm -rf classpath |
| * cvs co classpath |
| * cd classpath |
| Now run the auto tools as specified in the import process; then |
| cd .. |
| * Run 'scripts/makemake.tcl > sources.am' in the source tree |
| * Run automake for libgcj |
| |
| Now you should be ready to go. |
| |
| If you are working in a tree like this, you must remember to run |
| makemake.tcl and automake whenever you update your embedded classpath |
| tree. |
| |
| -- |
| |
| If you add a class to java.lang, java.io, or java.util |
| (including sub-packages, like java.lang.ref). |
| |
| * Edit gcj/javaprims.h |
| |
| * Go to the `namespace java' line, and delete that entire block (the |
| entire contents of the namespace) |
| |
| * Then insert the output of `perl scripts/classes.pl' into the file |
| at that point. This must be run from the build tree, in |
| <build>/classpath/lib; it uses the .class file name to determine |
| what to print. |
| |
| If you're generating a patch there is a program you can get to do an |
| offline `cvs add' (it will fake an `add' if you don't have write |
| permission yet). Then you can use `cvs diff -N' to generate the |
| patch. See http://www.red-bean.com/cvsutils/ |
