ANNOTATION-DIRECTED RUN-TIME SPECIALIZATION IN C

We present the design of a dynamic compilation system for C. Directed by a few declarative user annotations specifying where and on what dyn amic compilation is to take place, a binding time analysis computes th e set of run-time constants at each program point in each annotated pr ocedure's control flow graph; the analysis supports program-point-spec ific polyvariant division and specialization. The analysis results gui de the construction of a specialized run-time specializer for each dyn amically compiled region; the specializer supports various caching str ategies for managing dynamically generated code and supports mixes of speculative and demand-driven specialization of dynamic branch success ors. Most of the key cost/benefit trade-offs in the binding time analy sis and the run-time specializer are open to user control through decl arative policy annotations. Our design is being implemented in the con text of an existing optimizing compiler.