1 Things libgcj hackers should know
2 ---------------------------------
4 If you want to hack on the libgcj files you need to be aware of the
5 following things. There are probably lots of other things that should be
6 explained in this HACKING file. Please add them if you discover them :)
10 libgcj uses GNU Classpath as an upstream provider. Snapshots of
11 Classpath are imported into the libgcj source tree. Some classes are
12 overridden by local versions; these files still appear in the libgcj
15 To import a new release:
17 - Check out a classpath snapshot or take a release tar.gz file.
18 I use 'cvs export' for this. Make a tag to ensure future hackers
19 know exactly what revision was checked out; tags are of the form
20 'libgcj-import-DATE' (when using a tagged checkout do:
21 - ./autogen.sh && ./configure && make dist
22 to get a proper .tar.gz for importing below).
23 - Get a svn checkout of
24 svn+ssh://gcc.gnu.org/svn/gcc/branches/CLASSPATH/libjava/classpath
25 this contains "pure" GNU Classpath inside the GCC tree.
26 - Clean it up and get the files from a new version:
27 - find classpath -type f | grep -v /\.svn | grep -v /\.cvs | xargs rm
28 - tar zxf classpath-x.tar.gz
29 - cp -r classpath-x/* classpath
31 - svn status classpath | grep ^\! | cut -c8- | xargs svn remove
32 - svn status classpath | grep ^\? | cut -c8- | xargs svn add
33 - If there are any empty directories now they can be removed. You can find
34 candidates (dirs with files removed) with:
35 - for i in `svn status classpath | grep ^D | cut -c8-`; \
36 do ls -d `dirname $i`; done | uniq
37 - Update vendor branch
38 - svn commit classpath
39 - Note the new revision number (Xrev)
40 - Get a fresh svn trunk checkout and cd gcc/libjava
41 - Merge the changes between classpath versions into the trunk.
42 svn merge -rXrev-1:Xrev \
43 svn+ssh://gcc.gnu.org/svn/gcc/branches/CLASSPATH/libjava/classpath \
45 - Resolve any conflicts pointed out by svn status classpath | grep ^C
46 - Makefile.in files will be regenerated in the next step.
47 - Other files should have a "GCJ LOCAL" comment, and/or are mentioned
48 in the classpath/ChangeLog.gcj file.
49 (Don't forget to svn resolved files.)
50 - Use auto* to create configure, Makefile.in, etc
51 Make sure you have Automake 1.9.6 installed. Exactly that version!
52 You have to make sure to use the gcc libtool.m4 and gcc lt* scripts
55 cp ../../config.sub ../../config.guess .
56 aclocal -I m4 -I ../.. -I ../../config
62 scripts/makemake.tcl > sources.am
64 - Build, fix, till everything works.
65 Be sure to update gnu/classpath/Configuration.java to reflect
67 Possibly update the gcj/javaprims.h file with scripts/classes.pl
68 (See below, it can only be done after the first source->bytecode
70 You will need to configure with --enable-maintainer-mode and you
71 will need to update the .class files and generated CNI header files in
74 Over time we plan to remove as many of the remaining divergences as
77 File additions and deletions require running scripts/makemake.tcl
78 before running automake.
82 In general you should not make any changes in the classpath/
83 directory. Changes here should come via imports from upstream.
84 However, there are two (known) exceptions to this rule:
86 * In an emergency, such as a bootstrap breakage, it is ok to commit a
87 patch provided that the problem is resolved (by fixing a compiler
88 bug or fixing the Classpath bug upstream) somehow and the resolution
89 is later checked in (erasing the local diff).
91 * On a release branch to fix a bug, where a full-scale import of
92 Classpath is not advisable.
96 You can develop in a GCC tree using a CVS checkout of Classpath, most
97 of the time. (The exceptions are when an incompatible change has been
98 made in Classpath and some core part of libgcj has not yet been
101 The way to set this up is very similar to importing a new version of
102 Classpath into the libgcj tree. In your working tree:
104 * cd gcc/libjava; rm -rf classpath
107 Now run the auto tools as specified in the import process; then
109 * Run 'scripts/makemake.tcl > sources.am' in the source tree
110 * Run automake for libgcj
112 Now you should be ready to go.
114 If you are working in a tree like this, you must remember to run
115 makemake.tcl and automake whenever you update your embedded classpath
120 If you add a class to java.lang, java.io, or java.util
121 (including sub-packages, like java.lang.ref).
123 * Edit gcj/javaprims.h
125 * Go to the `namespace java' line, and delete that entire block (the
126 entire contents of the namespace)
128 * Then insert the output of `perl scripts/classes.pl' into the file
129 at that point. This must be run from the build tree, in
130 <build>/classpath/lib; it uses the .class file name to determine
133 If you're generating a patch there is a program you can get to do an
134 offline `cvs add' (it will fake an `add' if you don't have write
135 permission yet). Then you can use `cvs diff -N' to generate the
136 patch. See http://www.red-bean.com/cvsutils/