The invention provides a compiler for compiling source code files to generate corresponding object code files, the source code files including a first source code file and a second source code file, the first source code file having an initial occurrence of a unit of source code, and the second source code file having a subsequent occurrence of the unit of source code, the compiler including means for compiling the first source code file to generate the first object code file having a first unit of object code representing the initial occurrence of the unit of source code, and means for compiling the second source code file to generate the second object code file having a pointer to the first unit of object code, whereby the pointer supplants a second unit of object code representing the subsequent occurrence of the unit of source code.