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From: Dave Korn <dave.korn.cygwin@googlemail.com>
To: java@gcc.gnu.org, "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: Re: [JAVA,libtool]  Big libjava is biiiig.
Date: Wed, 06 May 2009 15:58:00 -0000	[thread overview]
Message-ID: <4A01B621.7020609@gmail.com> (raw)
In-Reply-To: <4A01B55C.6060700@gmail.com>

[ Boh!  I allowed my emailer to autocomplete the address and misdirected this
to the -patches list.  Apologies for the reposting to gcc@, but it'll break
the threading if I just send a forward to java@. ]


    Hi,

  As I'm sure everyone concerned is aware, libgcj is currently a bit of a
monolith.  Wighing in at 93M for a static archive, 73M for a shared library
(win32), it exports 82720 symbols.  Which is unfortunately 17184 more than the
system limit (64k) for a Windows DLL.

  The idea of breaking libjava up into smaller sublibraries has been mooted at
least a couple of times before (e.g. [*], [**]), but it's always raised issues
relating to backward compatibility.

  On windows we have no such back-compat issues to worry about; libjava has
not worked as a DLL in who-knows-how-long-if-ever.  I envisage that we could
very easily break it up into a bunch of separate (but presumably quite
inter-dependent) DLLs, and as a convenience we could provide a 'top-level'
libjava import library[***] that merged all the import libraries for the
individual DLLs.

  So I'm currently experimenting with a patch that adds a new option
"--enable-libgcj-sublibs" in libjava/configure.ac.  I may need to add a
dummy-link-and-relink stage to get the interdependencies working right, or I
might have to hack something in libtool, but the basic approach of adding a
bunch of extra libtool declarations based on $(filter)ing the full list of
dependencies from the complete libgcj_la_LIBADD definition seemed a reasonable
way to go:

+if BUILD_SUBLIBS
+libgcj_gnu_la_LIBADD = $(filter gnu/%.lo,$(libgcj_la_LIBADD)) -L$(here)/.libs
libgcj.la
+libgcj_java_la_LIBADD = $(filter java/%.lo,$(libgcj_la_LIBADD))
-L$(here)/.libs libgcj.la
+libgcj_javax_la_LIBADD = $(filter javax/%.lo,$(libgcj_la_LIBADD))
-L$(here)/.libs libgcj.la
+libgcj_misc_la_LIBADD = $(filter-out gnu/%.lo java/%.lo
javax/%.lo,$(libgcj_la_LIBADD)) -L$(here)/.libs libgcj.la
+endif

  Questions:

1)  Would this be a reasonable approach, specifically i) in adding a configure
option to cause sublibraries to be built, and ii) in using gmake's $(filter)
construct to crudely subdivide the libraries like this?

2)  Given that there's a bit of a logjam upstream, and not likely to be
another libtool release betwen now and the end of stage1, would it be
acceptable (in general) to hack on our in-tree libtool first and send patches
upstream second (thus still avoiding any potential future merge lossage)?


    cheers,
      DaveK
-- 
[*]   - http://gcc.gnu.org/ml/gcc/2005-04/threads.html#01450
[**]  - http://gcc.gnu.org/ml/java-patches/2005-q1/threads.html#00225
[***] - For those not familiar, when windows executables import symbols from
DLLs, they do so by statically linking against a so-named 'import library'
that contains .data section stubs that build the structures that constitute
the final exe's table of imports as understood by the runtime loader.



       reply	other threads:[~2009-05-06 15:58 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4A01B55C.6060700@gmail.com>
2009-05-06 15:58 ` Dave Korn [this message]
2009-05-06 16:15   ` Ralf Wildenhues
2009-05-06 16:27     ` David Daney
2009-05-06 16:31       ` Richard Guenther
2009-05-06 16:40         ` Andrew Haley
2009-08-22 13:24       ` Dave Korn
2009-08-22 16:33         ` Andrew Haley
2009-08-22 18:55           ` Dave Korn
2009-08-28 18:04         ` Tom Tromey
2009-08-28 18:16           ` David Daney
2009-08-28 19:56             ` Dave Korn
2009-05-06 16:57     ` Dave Korn
2009-05-07 21:49       ` Ralf Wildenhues
2009-05-11 17:14         ` Dave Korn
2009-05-11 17:26           ` Andrew Haley
2009-05-11 18:03             ` Dave Korn
2009-05-13 12:38             ` Dave Korn
2009-05-13 16:18               ` Andrew Haley
2009-05-13 17:59                 ` Dave Korn
2009-05-13 15:39           ` Dave Korn
2009-05-06 16:39   ` Andrew Haley
2009-05-06 16:45     ` Dave Korn
2009-05-06 17:12       ` Andrew Haley
2009-05-11 17:33         ` Dave Korn
2009-05-11 17:39           ` Andrew Haley
     [not found]     ` <7230133d0905060959h5371a608nff03cce1e1e98f47@mail.gmail.com>
2009-05-06 17:08       ` Dave Korn

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