Implementation implications of Ada generics

Abstract

Generic program units as defined in Ada pose several important design issues for compilers, both in semantic analysis and in runtime implementation. Chief among these issues are separate compilation of generic bodies and the sharing of code among several instantiations of a generic. An implementation is described that allows separate compilation of generic bodies with full semantic checking and that automatically shares instance bodies based on the characteristics of the actual parameters. A single instance body is generated for each "Instance class". Instance classes are formed by actual parameters with the same representation attributes.