Generate executable code for a target machine that is a faithful representation of the semantics of the source code Depends not only on the characteristics of the source language but also on detailed information about the target architecture. the structure of the runtime environment, and the operating system running on the target machine• Generate executable code for a target machine that is a faithful representation of the semantics of the source code • Depends not only on the characteristics of the source language but also on detailed information about the target architecture, the structure of the runtime environment, and the operating system running on the target machine