Abstract. We propose a construction that augments the precomputation step of a regular tree pattern matching algorithm to include cost analysis. The matching device generated is a pushdown automaton in contrast with the conventionallygenerated tree pattern matching automaton. Our technique can handle a larger class of cost augmented regular tree grammars than can be preprocessed byconventional methods, and has been tested on some input problem instances representing instruction sets for processors. 1

We propose a new technique for constructing code-generator generators, which combines the advantages of the Graham-Glanville parsing technique and the bottom-up tree parsing approach. Machine descriptions are similar to Yacc specifications. The construction effectively generates a pushdown automaton as the matching device. This device is able to handle ambiguous grammars, and can be used to generate locally optimal code without the use of heuristics. Cost computations are performed at preprocessing time. The class of regular tree grammars augmented with costs that can be handled by our system properly includes those that can be handled by bottom-up systems based on finite-state tree parsing automata. Parsing time is linear in the size of the subject tree. We have tested the system on specifications for some systems and report table sizes.

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