Crab: A C++ Library for Building Program Static Analyses

Windows	Ubuntu	OS X	Coverage
TBD		TBD

Description

Crab (CoRnucopia of ABstractions) is a C++ library for building program static analyses based on Abstract Interpretation.

Crab does not analyze directly a mainstream programming language such as C/C++ or Java but instead it analyzes its own CFG-based intermediate representation (CrabIR). This allows building analyses for different programming languages assuming a translator to CrabIR is available. In spite of its simple design, CrabIR is rich enough to represent languages such as LLVM bitcode.

Crab has been designed to have two kind of users:

1. Program analysis/verification tools that want to use invariants computed by abstract interpretation.

2. Researchers on abstract interpretation who would like to experiment with new abstract domains or fixpoint algorithms.

The available documentation can be found in our wiki.

Docker

A (nightly) pre-built version of Crab that runs all tests can be obtained using Docker:

docker pull seahorn/crab_elina:bionic
docker run -v `pwd`:/host -it seahorn/crab_elina:bionic

Requirements for compiling from sources

Crab is written in C++ and relies on the Boost library. The main requirements are:

• Modern C++ compiler supporting c++11
• Boost >= 1.65
• GMP
• MPFR (if -DCRAB_USE_APRON=ON or -DCRAB_USE_ELINA=ON)

In linux, you can install requirements typing the commands:

sudo apt-get install libboost-all-dev libboost-program-options-dev
sudo apt-get install libgmp-dev
sudo apt-get install libmpfr-dev	

Compiling from sources and installation

To install Crab, type:

mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX=_INSTALL_DIR_ ../
cmake --build . --target install 

The Boxes/Apron/Elina domains require third-party libraries. To avoid the burden to users who are not interested in those domains, the installation of the libraries is optional.

• If you want to use the Boxes domain then add -DCRAB_USE_LDD=ON option.

• If you want to use the Apron library domains then add -DCRAB_USE_APRON=ON option.

• If you want to use the Elina library domains then add -DCRAB_USE_ELINA=ON option.

Important: Apron and Elina are currently not compatible so you cannot enable -DCRAB_USE_APRON=ON and -DCRAB_USE_ELINA=ON at the same time.

For instance, to install Crab with Boxes and Apron, type:

mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX=_INSTALL_DIR_ -DCRAB_USE_LDD=ON -DCRAB_USE_APRON=ON ../
cmake --build . --target ldd && cmake ..
cmake --build . --target apron && cmake ..	
cmake --build . --target install 	

The tests directory contains many examples of how to build programs written in CrabIR and compute invariants using different analyses and abstract domains. To compile these tests type:

mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX=_INSTALL_DIR_ -DCRAB_USE_LDD=ON -DCRAB_USE_APRON=ON -DCRAB_ENABLE_TESTS=ON ../
cmake --build . --target ldd && cmake ..
cmake --build . --target apron && cmake ..	
cmake --build . --target install 	

and then, for instance, to run test1:

build/test-bin/test1

Using Crab in other C++ projects

To include Crab in your C++ application you need to:

• Include the C++ header files located at the _INSTALL_DIR_/crab/include, and

• Link your application with the Crab libraries installed in _INSTALL_DIR_/crab/lib.

If you compile with Boxes/Apron/Elina you need also to include _INSTALL_DIR_/EXT/include and link with _INSTALL_DIR_/EXT/lib where EXT=apron|elina|ldd.

CMake

If your project uses cmake then you just need to add in your project's CMakeLists.txt:

add_subdirectory(crab)
include_directories(${CRAB_INCLUDE_DIRS})

And then link your executable with ${CRAB_LIBS}

Make

If your project uses make, read this sample Makefile.