Abstract

We describe the current status of and provide performance results for a prototype compiler of Prolog to C. The compiler is novel in that it is designed to accept di#erent kinds of high-level information, typically obtained via an automatic analysis of the initial Prolog program and expressed in a standardized language of assertions, and use this information to optimize the resulting C code, which is then further processed by an o#-the-shelf C compiler. The basic translation process used essentially mimics an unfolding of a C-coded bytecode emulator with respect to the particular bytecode corresponding to the Prolog program. Optimizations are then applied to this unfolded program. This is facilitated by a more flexible design of the bytecode instructions and their lower-level components. This approach allows reusing a sizable amount of the machinery of the bytecode emulator: ancillary pieces of C code, data definitions, memory management routines and areas, etc., as well as mixing bytecode emulated code with natively compiled code in a relatively straightforward way. We report on the performance of programs compiled by the current version of the system, both with and without analysis information.

Citations