Hi,
I believe there are some interesting optimization opportunities that
flow from the move to generics that enables the proper use of
annotations. For example a code sequence such as:
static final int specialValue = 123;
void foo() {
Integer bar1 = Integer.valueOf(specialValue);
....
invoke some methods
...
Integer bar2 = Integer.valueOf(specialValue);
...
}
could be optimized to:
static final int specialValue = 123;
void foo() {
Integer bar1 = Integer.valueOf(specialValue);
....
invoke some methods
...
Integer bar2 = bar1;
...
}
if we knew that the intCache were holding an immutable value. Actually
there are more exciting optimizations discussed in this paper by Igor
Pechtchanski and Vivek Sarkar, in particular because of the immutability
of Strings:
http://citeseer.ist.psu.edu/pechtchanski02immutability.html
I'm interested in adding these optimization to the Jikes RVM, but
clearly the annotations need adding to Classpath. I was wondering what
kind of response this would get? I can imagine a gnu.pragma or
gnu.compilerhint package containing such annotations. It could also
contain similar compiler hints to those found in GCC attributes. The
Jikes RVM uses a package called org.vmmagic.pragma for some other
compiler tricks.
Interested in your responses, thanks,
Ian Rogers
--
http://www.cs.man.ac.uk/~irogers
