Processor modeling and code selection for retargetable compilation

Embedded processors in electronic systems typically are tuned to a few applications. Development of processor-specific compilers is prohibitively expensive and, as a result, such compilers, if existing, yield code of an unacceptable quality. To improve this code quality, we developed a processor model that captures the connectivity, the parallelism, and all architectural peculiarities of an embedded processor. We also implemented a retargetable and optimizing compiler working on this model. We present the graph-based processor model, and formally define the code generation task as binding the intermediate representation of an application to this model. We also present a new method for code selection, based on this processor model, that is capable of handling directed acyclic graphs instead of trees.