Description
(1) Reduce instruction granularity. Use an execution model, the Berkeley Abstract Machine(BAM), that retains the good features of the Warren Abstract Machine (WAM), a standard execution model for Prolog, but is more easily optimized and closer to a real machine.
(2) Exploit determinism. Compile deterministic programs with efficient conditional branches. Most predicates written by human programmers are deterministic, yet previous systems often compile them in an inefficient manner by simulating conditional branching with backtracking.
(3) Specialize unification. Compile unification to the simplest possible code. Unification is a general pattern-matching operation that can do many things in the implementation: pass parameters, assign values to variables, allocate memory, and do conditional branching.
(4) Dataflow analysis. Derive type information by global dataflow analysis to support these ideas.
Because of limitations of the dataflow analysis, the system is not yet competitive with the C language for all programs. I outline the work that is needed to close the remaining gap.