[fedora-java] Enhanced aot-compile script

[Fernando Nasser]

Hi,

I was thinking of having a 'aot-compile' command that would perform all tasks 
related to aot compilation.

For instance:

aot-compile

by itself would perform the additional compilation steps necessary to generate 
the .so files etc., as currently done.


aot-compile --rebuilddb

would do the rebuild-gcj-db thing


aot-compile --install <install arguments>

would allow a conditional installation step


and so forth.


In addition to that, 'aot-compile' would either work or be a no-op, depending on 
certain conditions, like the presence of GCJ in the system, and/or some 
system-wide or local override configuration mechanism.


This way, aot-compile statements can be added to an RPM spec file and that same 
spec file can be used to build bytecode or pre-compiled RPMs, depending on the 
settings.  Adding just this script to jpackage-utils would allow us to eliminate 
differences between the spec files upstream and in other distros, except for 
having to remove the "BuildArch: noarch" line.


It seems that there are a few cases to consider:

1) gcj is not installed  ==> automatic ==>  do not precompile

2) gcj is installed, but we don't want to pre-compile  ==> override with either 
system or local config (we could test for "BuildArch: noarch"...)  ==> do not 
precompile

3) gcj is installed, and we want to pre-compile ==> automatic ==> precompile

There are perhaps some other conditions, like you want to build the bytecode 
with another Java and then use gcj to pre-compile...


IMPORTANT: please note that aot-compile should not be tied to GCJ, but instead 
be a characteristic of any Java that is capable of pre-compilation.  QUESTION: 
how to accommodate the differences in pre-compilation mechanisms?  In any case, 
we should try and keep the command names generic so if necessary one day the 
JVMs that are AOT-capable can provide alternatives for those.


Regards to all,
Fernando