| 摘要 |
PROBLEM TO BE SOLVED: To inspect program codes, described by using an instruction set having type restrictions, at a high speed by a method which requires no re-execution and to efficiently use a storage device by finding the effective ranges of individual data. SOLUTION: A verifier 108 reads an instruction out of program codes 21, performs virtual execution, and reflects it on a virtual execution state 23. Snapshot tables 24 and 25 are prepared at points, corresponding to a branch source and a branch destination of the program codes 21, and the virtual execution state 23 at the instruction point of time is saved. When the instruction to be processed is an instruction 3041 reading and writing data, the verifier 108 sets a data field of a data structure 306, showing its contents, and when the instruction is an instruction 3042 using data, the verifier sets a data restriction field of the data structure 306 to identify the range that the data possibly has, thereby making a check on contradiction. The data restrictions 306 hold the maximum restrictions of the virtual execution, so that the virtual execution need not be redone.
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