values types for Java

[Andrew Haley]

Adam Megacz writes:
 > 
 > Andrew Haley <aph@redhat.com> writes:
 > > J.-D. Choi, M. Gupta, M. Serrano, V. C. Sreedhar, and S. Midki.
 > > Escape analysis for Java.  In Object-Oriented Programming, Systems,
 > > Languages, and Applications (OOPSLA), 1999. Languages (POPL), 2002.
 > > http://www.research.ibm.com/jalapeno/publication.html#oopsla99_escape
 > 
 > > I would like to add this to gcj.
 > 
 > Two problems for use with GCJ:
 > 
 > 1. They use interprocedural analysis, which is not compatible with
 >    separate compilation.

Why is that a problem?  You want intraprocedural optimzation, you
compile the files together.

 >    In a JVM, the compiler can trace through the implementations of
 >    all methods which are called; gcj cannot do that at compile time
 >    -- so you have no way of knowing if calling foo.bar() causes foo
 >    to stash a reference to itself somewhere else.  A JVM can simply
 >    inspect the implementation of the bar() method.

And so can we.

Andrew.