Re: [JAVA,libtool] Big libjava is biiiig.

[Andrew Haley <aph@redhat.com>]

Dave Korn wrote:
> Andrew Haley wrote:
>> Dave Korn wrote:
>>
>>> 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?
>> At program startup the first library would be loaded, it would load
>> the next, and so on.  There are a few parts of libgcj that are truly
>> independent, but I suspect that you'd always load almost all of it.
>> So, you'd have longer startup time for loading all those files.
> 
>   Compared to a single DLL that is unusably malformed because it exceeds
> system limits, that's still an improvement :)
> 
>> With regard to GNU libc platforms:
>>
>> You'd no longer be able to make so much use of fast calls between
>> functions in the same library; you'd have to go via the PLT.
>>
>> Also, dl_iterate_phdr() is used a great deal (for finding exception
>> regions, garbage collection, etc.) and it linearly scans the libraries
>> that are loaded.  So, the more libraries you have loaded, the slower
>> it goes.
>>
>> Now, I don't know how much of these characteristics are shared by
>> Windows, but I imagine some of them are.
> 
>   Yes, the inter-library calls would have to be dllimports and go through
> stubs (one extra indirect branch).  I don't know how dl_iterate_phdr works on
> win32 but I imagine that it's also linear in the number of libs.
> 
>> So, I suspect your best bet would be to split libgcj into core and
>> non-core libraries and not slice much more thinly than that.  I can
>> advise you what is core and what isn't.
> 
>   Please do, I'll happily try that approach since it might significantly
> simplify my inter-dependences problems.

Here's a starter list of non-core packages:

gnu/CORBA
gnu/classpath/management
gnu/java/awt/dnd/peer/gtk
gnu/java/awt/dnd/peer/gtk
gnu/java/awt/peer/gtk
gnu/java/awt/peer/qt
gnu/java/awt/peer/x
gnu/java/beans
gnu/java/lang/managementheaders
gnu/java/math
gnu/java/util/prefs/gconf
gnu/java/util/prefs/gconf
gnu/javax/management
gnu/javax/rmi
gnu/javax/sound/midi
gnu/javax/sound/sampled/gstreamer) ignore
gnu/xml/aelfred2
gnu/xml/dom
gnu/xml/libxmlj
gnu/xml/pipeline
gnu/xml/stream
gnu/xml/transform
gnu/xml/util
gnu/xml/validation
gnu/xml/xpath
java/lang/management
javax/imageio
javax/rmi
javax/xml
org/omg/CORBA
org/omg/CORBA_2_3
org/omg/CosNaming
org/omg/Dynamic
org/omg/DynamicAny
org/omg/IOP
org/omg/Messaging
org/omg/PortableInterceptor
org/omg/PortableServer
org/omg/SendingContext
org/omg/stub
org/relaxng
org/w3c
org/xml

Andrew.