| Summary: | This dissertation describes a system that constructs efficient, retargetable code generators and optimizers. chop reads nonprocedural descriptions of a computer's instruction set and of a naive code generator for the computer, and it writes an integrated code generator and peephole optimizer for it. The resulting code generators are very efficient because they interpret no tables; they are completely hard-coded. Nor do they build complex data structures to communicate between code generation and optimization phases. Interphase communication is reduced to the point that the code generator's output is often encoded in the program counter and conveyed to the optimizer by jumping to the right label. chop's code generator and optimizer are based on a very simple formalism, namely rewriting rules. An instrumented version of the compiler infers the optimization rules as it complies a training suite, and it records them for translation into hard code and inclusion into the production version. I have replaced the Portable C Compiler's code generator with one generated by chop. Despite a costly interface, the resulting compiler runs 30% to 50% faster than the original Portable C Compiler (pcc) and generates comparable code. This figure is diluted by common lexical analysis, parsing, and semantic analysis and by comparable code emission. Allowing for these, the new code generator appears to run approximately seven times faster than that of the original pcc.
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