For our prototype dynamic compilation system, designed and built by <a href="http://www.cs.washington.edu/homes/ausland">Joel Auslander</a> and <a href="http://www.cs.washington.edu/homes/matthai">Matthai Philipose</a>, we have enhanced the Multiflow compiler to act as the static compiler, and built a dynamic compiler that is automatically invoked at run-time.  Dynamic regions are identified by the programmer through a set of source-code annotations.  For each dynamic region, the programmer also specifies on which variables the region should be specialized.  A new version of the region is compiled at run-time for each set of values these variables have at the beginning of the dynamic region.  Furthermore, these annotated variables must be invariant throughout the dynamic region, and are called <em>run-time constants</em>.  <p>
