The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 21, 2001
Filed:
Sep. 24, 1998
John H. Field, Newtown, CT (US);
Ganesan Ramalingam, Croton-on-Hudson, NY (US);
Frank Tip, Mount Kisco, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An efficient program analysis method is provided for lazily decomposing aggregates (such as records and arrays) into simpler components based on the access patterns specific to a given program. This process allows us both to identify implicit aggregate structure not evident from declarative information in the program, and to simplify the representation of declared aggregates when references are made only to a subset of their components. The method can be exploited to yield: (i) a fast type analysis method applicable to program maintenance applications (such as date usage inference for the Year 2000 problem); and (ii) an efficient method for atomization of aggregates. More specifically, aggregate atomization decomposes all of the data that can be manipulated by the program into a set of disjoint atoms such that each data reference can be modeled as one or more references to atoms without loss of semantic information. Aggregate atomization can be used to adapt program analyses and representations designed for scalar data to aggregate data. In particular, atomization can be used to build more precise versions of program representations such as SSA form or PDGs. Such representations can in turn yield more accurate results for problems such as program slicing. Our techniques are especially useful in weakly-typed languages such as Cobol (where a variable need not be declared as an aggregate to store an aggregate value) and in languages where references to statically-defined sub-ranges of data such as arrays or strings are allowed.