Alternate and iterative analysis of computer programs for locating translatable code by resolving callbacks and other conflicting mutual dependencies

摘要

Information about the effects of calling each entry point in a program and information about external calls made by the program are recorded in an image information file. In addition to the addresses of the entry points and call destinations, the information may include any callback parameters and register usage associated with the entry points, and any definite values passed by the calls. When translating two separate but mutually dependent programs that are not easily merged for simultaneous translation, the image information files for the respective programs permit the programs to be alternately translated with rapid convergence by an iterative method of checked assumptions and re- translation. By matching the addresses of the entry points of a first program with the addresses of the external calls for a second program, and by matching the addresses of the external calls in the first program with the addresses of the program entry points in the second program, the relevant external calls and entry points in the image information file for the second program are identified. One program should be retranslated when a preceding retranslation of the other program changes the information for the matching calls and entry points in such a way that changed information might enable additional instructions to be discovered in the program under consideration for translation.