GCJ as cross-compiler to embedded system

Mon Dec 3 22:21:00 GMT 2001

>>>>> "Gustav" == Gustav KÃ¤lvesten <gustav.kalvesten@axis.com> writes:

Gustav> We are looking into bringing a JavaVM to our embedded systems
Gustav> platform (eCos as OS and ETRAX processor). We are currently
Gustav> using 'gcc' as cross-compiler for our development work. A
Gustav> question that has arisen is if it is possible to use 'gcj' to
Gustav> compile the class libraries of the JavaVM into native code?
Gustav> This should improve the speed drastically, right? Anyone who
Gustav> has done this and has any input on the difficulties and
Gustav> performance improvement?
When you say "class libraries of the JavaVM", what do you mean?
gcj can compile a lot of Java code. However, you can't really use it
to compile the base libraries. You have to use the base libraries
which come with it.
In the past we've had libgcj running on eCos. This port has
bit-rotted a bit, but it should be possible to resurrect it.
gcj can improve performance, but I believe the current state is that
it is about equivalent to the current generation of JITs. On the
other hand, in an embedded context it may be more attractive because
JITs memory in which to compile code, whereas gcj does not.
As always, which approach is best is highly dependent on the
constraints under which you operate.
Tom