XMUsuny / cgs

Concrete Constraint Guided Symbolic Execution

CGS (concrete-constraint guided searcher) is a dapendency-based path prioritization method for classical symbolic execution. It is motivated by an important observation that concrete branching conditions encompass a significant majority and a large portion of them are only partially covered. Therefore, there is a great potential to improve overall code coverage by guiding symbolic execution towards covering more concrete branches.

The folder IDA and KLEE contains the codes to implement our methods in Section 3 in our paper in ICSE '24.

The artifacts of motivation and experiment be found on zenodo.

Installation

Install LLVM 11.1.0 first and build:

1.Branch dependency analysis: Installation

2.KLEE (using STP solver): Building KLEE

Usage

First, set the following environment variables:

export SANDBOX_DIR=/tmp
export SOURCE_DIR=/path-to/cgs
export OUTPUT_DIR=/path-to/results

Then, build program in benchmark folder.

Next, generate new llvm bitcode (new_benchmark and stat folders are created):

python3 run.py [program] gen

Last, use our klee to test:

python3 run.py [program] run [searcher]

Moreover, we provide an option COV_STATS in run.py. If it is set to True before running klee, we can collect the statistics about symbolic and concrete branching conditions and use our modified klee-stats to show the results:

------------------------------------------------------------------------------------------------------------
|      Path       |  Instrs|  Time(s)|  ICov(%)|  BCov(%)|  ICount|  PCB|  FCB|  TC|  SC|  CC|  FCSC|  FCCC|
------------------------------------------------------------------------------------------------------------
|random-path/grep/|31573693|  3792.19|    27.68|    17.60|   93708|    0|    0|1404| 120|1372|    85|   385|
------------------------------------------------------------------------------------------------------------

PCB=Partially Covered Branches
FCB=Fully Covered Branches
TC=Total (Branching) Conditions
SC=Symbolic (Branching) Conditions
CC=Concrete (Branching) Conditions
FCSC=Fully Covered Symbolic (Branching) Conditions
FCCC=Fully Covered Concrete (Branching) Conditions

PCB and FCB are non-zero only if we set COV_STATS to False.

Cite our paper

@inproceedings{XXX,
  author = {Yue Sun, Guowei Yang, Shichao Lv, Zhi Li, Limin Sun},
  title = {Concrete Constraint Guided Symbolic Execution},
  year = {2024},
  address = {Lisbon, Portugal},
  url = {https://doi.org/10.1145/3597503.3639078},
  numpages = {13},
  series = {ICSE '24}
}