Eliminating Path Redundancy via Postconditioned Symbolic Execution

Symbolic execution is emerging as a powerful technique for generating test inputs systematically to achieve exhaustive path coverage of a bounded depth. However, its practical use is often limited by path explosion because the number of paths of a program can be exponential in the number of branch c...

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Published in:	IEEE transactions on software engineering Vol. 44; no. 1; pp. 25 - 43
Main Authors:	Yi, Qiuping, Yang, Zijiang, Guo, Shengjian, Wang, Chao, Liu, Jian, Zhao, Chen
Format:	Journal Article
Language:	English
Published:	New York IEEE 01.01.2018 IEEE Computer Society
Subjects:	Concrete Explosions Input variables Pruning Redundancy Software Symbolic execution Syntactics Testing testing and debugging testing tools
ISSN:	0098-5589, 1939-3520
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Abstract	Symbolic execution is emerging as a powerful technique for generating test inputs systematically to achieve exhaustive path coverage of a bounded depth. However, its practical use is often limited by path explosion because the number of paths of a program can be exponential in the number of branch conditions encountered during the execution. To mitigate the path explosion problem, we propose a new redundancy removal method called postconditioned symbolic execution. At each branching location, in addition to determine whether a particular branch is feasible as in traditional symbolic execution, our approach checks whether the branch is subsumed by previous explorations. This is enabled by summarizing previously explored paths by weakest precondition computations. Postconditioned symbolic execution can identify path suffixes shared by multiple runs and eliminate them during test generation when they are redundant. Pruning away such redundant paths can lead to a potentially exponential reduction in the number of explored paths. Since the new approach is computationally expensive, we also propose several heuristics to reduce its cost. We have implemented our method in the symbolic execution engine KLEE [1] and conducted experiments on a large set of programs from the GNU Coreutils suite. Our results confirm that redundancy due to common path suffix is both abundant and widespread in real-world applications.
AbstractList	Symbolic execution is emerging as a powerful technique for generating test inputs systematically to achieve exhaustive path coverage of a bounded depth. However, its practical use is often limited by path explosion because the number of paths of a program can be exponential in the number of branch conditions encountered during the execution. To mitigate the path explosion problem, we propose a new redundancy removal method called postconditioned symbolic execution. At each branching location, in addition to determine whether a particular branch is feasible as in traditional symbolic execution, our approach checks whether the branch is subsumed by previous explorations. This is enabled by summarizing previously explored paths by weakest precondition computations. Postconditioned symbolic execution can identify path suffixes shared by multiple runs and eliminate them during test generation when they are redundant. Pruning away such redundant paths can lead to a potentially exponential reduction in the number of explored paths. Since the new approach is computationally expensive, we also propose several heuristics to reduce its cost. We have implemented our method in the symbolic execution engine KLEE [1] and conducted experiments on a large set of programs from the GNU Coreutils suite. Our results confirm that redundancy due to common path suffix is both abundant and widespread in real-world applications.
Author	Shengjian Guo Chao Wang Chen Zhao Qiuping Yi Jian Liu Zijiang Yang
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References	ref57 ref56 ref12 ref15 mcmillan (ref25) 2006 ref58 ref14 ref53 ref55 sen (ref52) 2015 ref54 ref10 ramos (ref11) 2015 nori (ref26) 2009 mcmillan (ref16) 2010 ref19 cadar (ref1) 2008 ref51 ref50 albarghouthi (ref37) 2012 ref46 ref45 ref48 ref47 d'silva (ref35) 2010 ref41 ref44 pham (ref13) 2015 rojas (ref42) 2013 ref43 weissenbacher (ref34) 2012 jaffar (ref18) 2009 sen (ref4) 2005 ref9 ref6 ref5 ref40 beyer (ref32) 2012 pasareanu (ref7) 2009; 11 ciortea (ref21) 2009; 43 ref36 bugrara (ref49) 2013 ref30 jaffar (ref17) 2008 kroening (ref33) 2011 ref2 jaffar (ref31) 2011 ref39 ref38 godefroid (ref3) 2008 ref24 ref67 ref23 ref64 ref20 ref63 ref66 ref22 ref65 ref27 ref29 ma (ref59) 2011 avgerinos (ref8) 2011 ref60 jaffar (ref28) 2012 ref62 ref61
References_xml	– ident: ref66 doi: 10.1109/ICSE.2013.6606713 – start-page: 151 year: 2008 ident: ref3 article-title: Automated whitebox fuzz testing publication-title: Proc Usenix Symp Netw Distrib Syst Security – ident: ref5 doi: 10.1007/11817963_38 – start-page: 123 year: 2006 ident: ref25 article-title: Lazy abstraction with interpolants publication-title: Proc Int Conf Comput Aided Verification doi: 10.1007/11817963_14 – ident: ref19 doi: 10.1007/978-3-642-31424-7_43 – ident: ref12 doi: 10.1145/1950365.1950396 – ident: ref46 doi: 10.1145/2771783.2771802 – ident: ref60 doi: 10.1145/2001420.2001423 – ident: ref65 doi: 10.1109/ICSE.2012.6227146 – ident: ref45 doi: 10.1145/2771783.2771806 – ident: ref29 doi: 10.1007/978-3-319-11164-3_27 – start-page: 178 year: 2009 ident: ref26 article-title: The yogi project: Software property checking via static analysis and testing publication-title: Proc Int Conf Tools and Algorithms Constr and Anal Syst – start-page: 263 year: 2005 ident: ref4 article-title: CUTE: A concolic unit testing engine for C publication-title: Proc 2nd ACM SIGSOFT Symp on Foundations of Software Engineering doi: 10.1145/1095430.1081750 – ident: ref67 doi: 10.1145/2338965.2336771 – ident: ref47 doi: 10.1145/1180405.1180445 – start-page: 758 year: 2012 ident: ref28 article-title: TRACER: A symbolic execution tool for verification publication-title: Proc 24th Int Conf Comput Aided Verification doi: 10.1007/978-3-642-31424-7_61 – ident: ref64 doi: 10.1145/1993498.1993558 – ident: ref40 doi: 10.1007/978-3-540-78800-3_28 – start-page: 129 year: 2010 ident: ref35 article-title: Interpolant strength publication-title: Proc Int Conf Verification Model Checking Abstract Interpretation doi: 10.1007/978-3-642-11319-2_12 – start-page: 199 year: 2013 ident: ref49 article-title: Redundant state detection for dynamic symbolic execution publication-title: Proc USENIX Annu Tech Conf – ident: ref2 doi: 10.1145/1065010.1065036 – ident: ref6 doi: 10.1109/ASE.2008.69 – ident: ref54 doi: 10.1145/1985793.1985971 – start-page: 842 year: 2015 ident: ref52 article-title: MultiSE: Multi-path symbolic execution using value summaries publication-title: Proc Power Eng Meeting – start-page: 396 year: 2011 ident: ref31 article-title: Unbounded symbolic execution for program verification publication-title: Proceedings of the 2nd International Conference on Runtime Verification – ident: ref41 doi: 10.1145/1706299.1706307 – volume: 43 start-page: 5 year: 2009 ident: ref21 article-title: Cloud9: A software testing service publication-title: Operating Syst Rev doi: 10.1145/1713254.1713257 – start-page: 106 year: 2012 ident: ref32 article-title: Algorithms for software model checking: Predicate abstraction versus impact publication-title: Proc Formal Methods Comput -Aided Des – ident: ref20 doi: 10.1145/1390630.1390635 – ident: ref22 doi: 10.1145/1831708.1831732 – ident: ref61 doi: 10.1145/1755913.1755946 – ident: ref43 doi: 10.1109/ICSE.2015.79 – ident: ref56 doi: 10.1109/TSE.2015.2490067 – ident: ref14 doi: 10.1145/1190216.1190226 – volume: 11 start-page: 339 year: 2009 ident: ref7 article-title: A survey of new trends in symbolic execution for software testing and analysis publication-title: Int J Softw Tools Technol Transfer doi: 10.1007/s10009-009-0118-1 – ident: ref48 doi: 10.1145/2254064.2254088 – ident: ref15 doi: 10.1109/ICSE.2007.41 – ident: ref50 doi: 10.1145/2568225.2568293 – start-page: 297 year: 2008 ident: ref17 article-title: Efficient memoization for dynamic programming with ad-hoc constraints publication-title: Proc 23rd Nat Conf Artif Intell – ident: ref30 doi: 10.1145/2491411.2491425 – ident: ref44 doi: 10.1145/2393596.2393665 – ident: ref9 doi: 10.1145/1450058.1450087 – ident: ref24 doi: 10.1109/ICST.2012.114 – start-page: 49 year: 2015 ident: ref11 article-title: Under-constrained symbolic execution: Correctness checking for real code publication-title: 24th USENIX Security Symp – start-page: 454 year: 2009 ident: ref18 article-title: An interpolation method for CLP traversal publication-title: Proc Int Conf Principles Practice Constraint Program – start-page: 104 year: 2010 ident: ref16 article-title: Lazy annotation for program testing and verification publication-title: Proc Int Conf Comput Aided Verification doi: 10.1007/978-3-642-14295-6_10 – ident: ref27 doi: 10.1007/978-3-540-78800-3_33 – ident: ref55 doi: 10.1109/ASE.2013.6693084 – start-page: 95 year: 2011 ident: ref59 article-title: Directed symbolic execution publication-title: Proc 18th Int Symp Static Anal – ident: ref10 doi: 10.1109/ICSE.2013.6606558 – ident: ref23 doi: 10.1145/2384616.2384654 – ident: ref62 doi: 10.1145/2451116.2451152 – start-page: 556 year: 2012 ident: ref34 article-title: Wolverine: Battling bugs with interpolants-(competition contribution) publication-title: Proc Int Conf Tools and Algorithms Constr and Anal Syst – ident: ref36 doi: 10.1007/978-3-642-27940-9_4 – ident: ref57 doi: 10.1145/2509136.2509553 – ident: ref51 doi: 10.1145/1966445.1966475 – ident: ref63 doi: 10.1109/ICSE.2015.80 – ident: ref38 doi: 10.1145/129393.129398 – start-page: 209 year: 2008 ident: ref1 article-title: KLEE: Unassisted and automatic generation of high-coverage tests for complex systems programs publication-title: Proc USENIX Symp on Operating System Design and Implementation – year: 2013 ident: ref42 article-title: Compositional symbolic execution through program specialization publication-title: Proc 1st Workshop Bytecode Semantics Verification Anal Transformation – start-page: 573 year: 2011 ident: ref33 article-title: Interpolation-based software verification with wolverine publication-title: Proc 23rd Int Conf Comput Aided Verification doi: 10.1007/978-3-642-22110-1_45 – start-page: 283 year: 2011 ident: ref8 article-title: AEG: Automatic exploit generation publication-title: Proc Usenix Symp Netw Distrib Syst Security – ident: ref39 doi: 10.1007/978-3-540-73368-3_52 – start-page: 672 year: 2012 ident: ref37 article-title: UFO: A framework for abstraction- and interpolation-based software verification publication-title: Proc 24th Int Conf Comput Aided Verification doi: 10.1007/978-3-642-31424-7_48 – ident: ref58 doi: 10.1145/2635868.2635872 – start-page: 891 year: 2015 ident: ref13 article-title: Hercules: reproducing crashes in real-world application binaries publication-title: Proceedings of the International Conference on Software Engineering ICSE'94 – ident: ref53 doi: 10.1109/ICSM.2010.5609565
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Snippet	Symbolic execution is emerging as a powerful technique for generating test inputs systematically to achieve exhaustive path coverage of a bounded depth....
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SubjectTerms	Concrete Explosions Input variables Pruning Redundancy Software Symbolic execution Syntactics Testing testing and debugging testing tools
Title	Eliminating Path Redundancy via Postconditioned Symbolic Execution
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