Abstract: A compiler framework uses a generic "shell" and a generic back end (where the code generator is target-specific). The generic back end provides the functions of optimization, register and memory allocation, and code generation. The code generation function of the back end may be targeted for any of a number of computer architectures. A front end is tailored for each different source language, such as Cobol, Fortran, Pascal, C, C++, etc. The front end scans and parses the source code modules, and generates from them an intermediate language representation of the source code programs expressed in the source code. The intermediate language represents any of the source code languages in a universal manner, so the interface between the front end and back end is of a standard format, and need not be rewritten for each language-specific front end. A feature is the type definition (TD) mechanism, referred to a the TD module.