Hello All
I am not sure to understand what exactly is the current status
http://gcc.gnu.org/ml/gcc/2010-02/msg00270.html of GCC 4.5 with respect
to plugins. I believe I understand much more its current status w.r.t.
to other GCC roles (in particular, the major role of generating object
code from a source one).
Plugins are quite a disruptive feature of 4.5. There is no compatibility
issues, since it is a new feature. Even more, there are not many
existing plugins to actually test that feature (it is a chicken & egg
issue: people will probably start to develop plugins only after 4.5 is
released).
Plugins are very different of LTO (link time optimization), another
disruptive feature of 4.5. Because LTO has a natural way of being
tested: we want that most [not too big] programs which are compiled by
gcc-4.5 without LTO to be buildable with LTO (i.e. compiled & linked
with gcc -flto), preferably without loss of performance, and this is an
easy to test & quite objective criterion. We have no simple criterion
for plugins.
To be more specific, I feel that current plugin machinery could still be
improved for the 4.5 time frame. I am more precisely thinking of:
a. some people could want more plugin events to be added inside GCC,
thus having more plugin hooks.
b. the plugin invocation convention could be improved. In particular,
one could have (as it is the case of many other major plugin-ehancable
software, e.g. Mozilla, Qt, Gtk, ...) a specific directory to install
plugins, and invoke gcc -fplugin=treehydra instead of gcc
-fplugin=/some/distribution/specific/path/to/treehydra.so ; I did
propose a patch for that
http://gcc.gnu.org/ml/gcc-patches/2010-02/msg00353.html
http://gcc.gnu.org/ml/gcc-patches/2010-01/msg00476.html but nobody
really cares :-( Would it be appropriate to issue a ping^5 for it?
c. building plugins (e.g. MELT) requiring gengtype needs both the GCC
source directory & the GCC build directory (filled by a build which has
been installed) - this requirement is unusual, distribution-unfriendly,
and difficult to cope with. I do admit that correcting this kludge is a
bit of work. http://gcc.gnu.org/ml/gcc/2010-03/msg00129.html - more
generally, with plugins, several internal tools of GCC (notably
gengtype, but probably also others) should become installed for plugin
developers.
In general, is 4.5 frozen to the point that no (even small) plugin
improvement could be accepted (not even point b)? And could some small
patch (like my point b) be accepted between hypothetical 4.5.0 & 4.5.1
releases?
And should I formally make a problem report on bugzilla about each of
these issues?
The point b is in my view of major importance for plugin users, because
it is the only way to permit popular plugins to appear and be used the
same way (thru the same gcc invocation) on various e.g. Linux distributions.
BTW, with Zbigniew Chamski I will give a talk (in French) about GCC
plugins at Solutions Linux next week in Paris.
Also, MELT has now a script to build it as a plugin, but the gengtype
requirement that the GCC source & build tree [of the GCC compiler into
which MELT is plugged in] should be available is a significant
annoyance, in particular to Debian GCC packagers.
regards
--
Basile STARYNKEVITCH http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mines, sont seulement les miennes} ***
