1. A computer-implemented method, comprising: prior to compilation of a program into machine code, generating directives about the program, the directives for directing compilation of the program into machine code by a just-in-time compiler; embedding the directives into a bytecode representation of the program, stored in a machine-readable medium, wherein at least a portion of the bytecode representation can be one-pass compiled into machine code by the just-in-time compiler directed by the embedded directives and compiling the at least a portion of the bytecode representation into machine code in one-pass with the just-in-time compiler using the embedded directives.