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CREST

CREST is a concolic test generation tool for C.

Thanks for downloading and trying out CREST.

You can get the latest version of CREST, as well as news and announcements at CREST's homepage: https://burn.im/crest .

If you want to cite CREST, please refer to the (short) paper: Burnim, Sen, "Heuristics for Dynamic Test Generation", Proceedings of the 23rd IEEE/ACM International Conference on Automated Software Engineering (ASE), 2008.

You can find a list of papers using CREST at https://burn.im/crest/#publications .

NOTE: CREST is no longer being actively developed, but questions are still answered on the CREST-users mailing list -- crest-users@googlegroups.com and https://groups.google.com/forum/#!forum/crest-users .

Preparing a Program for CREST

To use CREST on a C program, use functions CREST_int, CREST_char, etc., declared in "crest.h", to generate symbolic inputs for your program. For examples, see the programs in test/.

For simple, single-file programs, you can use the build script "bin/crestc" to instrument and compile your test program.

CREST can be used to instrument multi-file programs, too -- instructions may be added later. In the meantime, you can take a look at an example, instrumented form of grep-2.2, available at https://github.com/jburnim/crest/tree/master/benchmarks/grep-2.2 . For further information, please see this post on the CREST-users mailing list.

Running Crest

CREST is run on an instrumented program as:

bin/run_crest PROGRAM NUM_ITERATIONS -STRATEGY

Possibly strategies include: dfs, cfg, random, uniform_random, random_input. Some strategies take optional parameters.

Example commands to test the "test/uniform_test.c" program:

cd test
../bin/crestc uniform_test.c
../bin/run_crest ./uniform_test 10 -dfs

This should produce output roughly like:

... [GARBAGE] ...
Read 8 branches.
Read 13 nodes.
Wrote 6 branch edges.

Iteration 0 (0s): covered 0 branches [0 reach funs, 0 reach branches].
Iteration 1 (0s): covered 1 branches [1 reach funs, 8 reach branches].
Iteration 2 (0s): covered 3 branches [1 reach funs, 8 reach branches].
Iteration 3 (0s): covered 5 branches [1 reach funs, 8 reach branches].
Iteration 4 (0s): covered 7 branches [1 reach funs, 8 reach branches].
GOAL!
Iteration 5 (0s): covered 8 branches [1 reach funs, 8 reach branches].

NOTE: run_crest and crestc currently leave a lot of files lying around, some of which are temporary and some of which must be kept. In particular, "cfg_branches" and "branches" are output by the instrumentation process and are needed to run run_crest, and run_crest produces "coverage", a list of the ID's of all covered branches.

Setup

CREST depends on Yices 1, an SMT solver tool and library available at http://yices.csl.sri.com/old/download-yices1.shtml. To build and run CREST, you must download and install Yices version 1 and change YICES_DIR in src/Makefile to point to Yices location.

CREST uses CIL to instrument C programs for testing. A modified distribution of CIL is included in directory cil/. To build CIL, simply run "configure" and "make" in the cil/ directory.

Finally, CREST can be built by running "make" in the src/ directory.

License

CREST is distributed under the revised BSD license. See LICENSE for details.

This distribution includes a modified version of CIL, a tool for parsing, analyzing, and transforming C programs. CIL is written by George Necula, Scott McPeak, Wes Weimer, Ben Liblit, and Matt Harren. It is also distributed under the revised BSD license. See cil/LICENSE for details.