US Patent 7546591 Program conversion and data processor

Enhances program efficiency by performing optimization with reduced influence of an explicit instruction for adjusting an image of local variables of a code column executed by means of an interpreter and a compiled code column. An example embodiment, includes: setting code that is ignorable in predetermined transformation for a second code column among codes in a first code column, which affects transformation of the second code column; and performing predetermined transformation for the second code column by ignoring the code that is set to be ignorable, when an execution object of a program transitions from a first code column executed by means of an interpreter to a second compiled code column. It can further include generating a compensating code required for transforming a second code column including propagation of a copy instruction, and inserting the code into a first code column prior to transformation of the second code column.