Fast, Effective Dynamic Compilation
Susan Eggers

Dynamic compilation enables constant-based optimizations on the values of
invariant data computed at run-time.  Using the values of these run-time
constants, a dynamic compiler can eliminate their memory loads, perform
constant propagation and folding, remove branches they determine, and
fully unroll loops they bound, all at run-time.  However, the performance
benefits of the more efficient, dynamically-compiled code are offset by
the run-time cost of the dynamic compile.  Our approach to dynamic
compilation strives for both fast dynamic compilation and high-quality
dynamically-compiled code: the programmer annotates regions of the programs
that should be compiled dynamically;  a static optimizing compiler
automatically produces machine-code templates that have been pre-optimized
by an analysis that identifies which variables will be constant at run-time;
and a simple, dynamic compiler copies the templates, patching in the
computed values of the run-time constants, to produce optimized, executable
code.  Our work targets general-purpose, imperative programming languages,
initially C.  Initial experiments applying dynamic compilation to two C
programs have produced speed-ups over statically-compiled versions of 1.6
and 1.9.

In this talk I will describe our current dynmamic compilation framework,
and outline the direction of our future work.