OpenJDK compilation

[Kelly O'Hair]

Sorgius, Aaron wrote:
> Oops... sorry Xerxes, I left you off my replies.  Just trying to get Java on ARM 
> 
> 
>> Aaron Sorgius wrote:
> 
>>> I've been trying to google for some how-to's on getting OpenJDK 
>>> compiled on ARM (cortex-A8 specifically).  I came across your website 
>>> and it looks like you are doing some things that might be able to 
>>> point me in a helpful direction.  I was hoping to cross compile using 
>>> an Ubuntu machine.  I have it compiling natively on Ubuntu, but don't 
>>> know the best way to build for ARM.  Any suggestions?
> 
> OpenJDK doesn't support cross-compilation.  It should.

In general The JDK team hasn't had a need to do much cross-compilation,
with the exception of our past use of Windows X86 to build Windows IA64
(which is a special case of cross-compilation).

In the hotspot Makefiles there is a REMOTE variable that can be used to
cause certain rules to be built with a prefix, such as 'ssh someothermachine'.
This is usually used to run the JDK javac on a different machine, since
it doesn't matter where the class file is compiled (this REMOTE assumes
a shared file system of course).

The JDK builds require a bootstrap JDK, but the JDK build can easily
be primed on a supported machine, and the native libraries displaced.
The JDK Makefiles don't have any kind of REMOTE feature, but that's
certainly possible. (See jdk/make/common/shared/Defs-java.gmk)
http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/tip/make/common/shared/Defs-java.gmk

The JDK build itself is not used during the build procedure until it's
needed to build the demos, just before the JDK images target.
So I imagine the build can only get as far as just before creating
images.

So doing cross compilation is certainly possible, just not easy.
Every time I talk to someone wanting cross-compilation, it turns out
that they have a very specific situation of cross-compilation, not
all situations are the same. I don't see a solution for all situations.

-kto

> 
> 
> Sorgius, Aaron wrote:
>> Hi Andrew,
>>
>> Guess I won't go that route then :)
>> Have you built it natively on ARM?  
> 
>> Can it be done without the binaries for the encumbered components (and 
>> just not use that functionality), or do some exist for ARM now?
> 
> It does build ATM, and you don't need the encumbered components if you build from the IcedTea sources.  However, it's segfaulting at startup.
> 
> Andrew.
> 
> 
> Sorgius, Aaron wrote:
>> Hmm... that's not good.  So there is currently no working build for ARM at the moment?  Any place I can check for status updates on the progress so I don't have to bother you with emails?  :)
> 
> Talk to Xerxes.  He's doing the work.
> 
> It's a good idea to Cc: the distro-pkg-dev at openjdk.java.net
> 
> Andrew.
> 
> 
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