jyi / fangelix

FAngelix

FAngelix is a program repair tool for C programs. It is an extension of Angelix, a constraint-based (semantics-based) repair tool. FAngelix uses a guided search algorithm based on MCMC (Markov Chain Monte Carlo) sampling and is generally faster than Angelix.

If you use FAngelix in your research project, please include the following citation:

@article{yi2022fangelix,
  title={Speeding up constraint-based program repair using a search-based technique},
  author={Yi, Jooyong and Ismayilzada, Elkhan},
  journal={Information and Software Technology},
  volume={146},
  pages={106865},
  year={2022},
  publisher={Elsevier}
}

Installation

The installation steps can be identified with the provided Dockerfile. A Docker container can also be obtained as follows:

docker pull jayyi/fangelix:2021-Nov-09

Running FAngelix

Before running FAngelix, make sure to run the following to set FAngelix environment:

. activate

FAngelix is implemented as an extension of Angelix, keeping the same command-line interface of Angelix. Let's fix a buggy source code, test.c, available in the test/loop-condition directory with FAngelix as follows.

# Assume that we are in the root directory of fangelix.
cd tests/loop-condition
angelix src test.c oracle 1 2 3

The first parameter, src, describes the directory where the buggy source code test.c is located. The oracle and 1 2 3 describe a test script and test IDs. FAngelix performs a guided search based on the cost of executions and the oracle contains a cost function named cal_diff. If a cost function is not provided, FAngelix performs without a cost function. For the above example, FAngelix will finish with output similar to the following:

INFO     synthesis       fixing expression (30, 10, 30, 14): (n > 1) ---> (n >= 1)
INFO     repair          candidate fix synthesized
INFO     transformation  applying patch to validation source
INFO     project         building validation source
INFO     testing         running test '1' of validation source
INFO     testing         output code: 0
INFO     testing         running test '2' of validation source
INFO     testing         output code: 0
INFO     testing         running test '3' of validation source
INFO     testing         output code: 0
INFO     repair          patch successfully generated in 14s (see src-2021-Nov08-175730.patch)
SUCCESS

FAngelix by default fixes two defect classes: if conditions and loop conditions. To fix an assignment, use --defect assignments as follows:

cd tests/assignment-if
angelix src test.c oracle 1 2 3 --assert assert.json --defect assignments

When fixing an assignment, FAngelix uses symbolic execution tool KLEE and the expected output needs to be specified separately in the assert.json file. For a detailed description, please refer to the tutorial of Angelix. For the second example, FAngelix will finish with output similar to the following:

INFO     synthesis       fixing expression (13, 7, 13, 11): (a + b) ---> (a - b)
INFO     repair          candidate fix synthesized
INFO     transformation  applying patch to validation source
INFO     project         building validation source
INFO     testing         running test '1' of validation source
INFO     testing         output code: 0
INFO     testing         running test '2' of validation source
INFO     testing         output code: 0
INFO     testing         running test '3' of validation source
INFO     testing         output code: 0
INFO     repair          patch successfully generated in 36s (see src-2021-Nov08-180056.patch)
SUCCESS

FAngelix maintains the original algorithm of Angelix. The following command can be used to use the Angelix mode instead.

cd tests/loop-condition
angelix src test.c oracle 1 2 3 --assert assert.json --angelic-search-strategy symbolic --klee-timeout 10

Experimental scripts and data

Experimental scripts and data are available here.