Hewlett-packard Development Company, L.p.

Christopher J Dollin

Vaideswar Gopalakrishnan

Roy T Oberhauser

Laura J Dickey

Steven Frederick Knight Leach

The system of the present disclosure comprises memory for storing a compiled program. The system further comprises logic configured to translate the compiled program into a set of human-readable instructions and construct a coarse tree representing the program flow of the set of human-readable instructions. The logic is further configured to compute a first type signature representative of a code construct comprising alternative code paths within the program flow and determine a second type signature representative of the coarse tree based upon the first type signature.

Code verification system and method

A code verification system is utilized to type check compiled code. The code verification system includes memory and a code verifier. The memory is utilized to store a compiled program. The code verifier analyzes instructions of the program and generates a plurality of type signatures based on the instructions The type signatures indicate the input type constraints and the output type descriptions of the instructions, and the code verifier analyzes the type signatures to detect a type error.

A system and method are provided that allow for improved code sequence verification through the use of an abstract syntax tree. This is accomplished by first constructing an abstract syntax tree from the code sequence and then determining whether the abstract syntax tree satisfies a predefined set of conditions indicative of the code sequence being executable on the computer without generating a predefined class of execution errors. The abstract syntax tree is constructed by reassembling the code sequence into a plurality of instructions, combining the instructions into a plurality of blocks, examining the blocks to determine entry points of a plurality of loops, and tagging locations in the series of instructions where control is transferred at the end of each loop. The instructions, blocks, loops and tagged locations are then examined to generate a plurality of control structures (the coarse structure). Finally, the instructions, blocks, loops, tagged locations and control structures are examined to generate a plurality of form expressions (the fine structures).

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Bristol, United Kingdom

Christopher J Dollin