1. A method of forming an executable program from a plurality of object code modules, each object code module comprising section data and an ordered sequence of relaxation instructions including a first type defining relocation operations and a second type controlling linker operations, each relaxation instruction having associated therewith a unique instruction count of a sequence of instruction counts, wherein the second type includes a jump relaxation instruction which specifies the instruction count of a relaxation instruction to be subsequently read, the method comprising: (a) reading each relaxation instruction in the ordered sequence defined by the sequence of instruction counts; and (b) where said relaxation instruction is of the first type defining a relocation operation, executing that relocation operation on section data to which it relates, and where said relaxation instruction is a jump relaxation instruction, the next relaxation instruction which is read is that of the instruction count specified in the jump relaxation instruction.