KLEE

master branch

Building KLEE (recommended)

with LLVM 3.4

NOTE: This is the documentation for the version of KLEE in the master branch which might differ from released KLEE. For documentation relevant to a particular KLEE release see the releases page.

The current procedure for building KLEE with LLVM 3.4 (recommended) is outlined below. These instructions use KLEE’s new CMake based build system. If you wish to build with KLEE’s older build system then see here.

If you want to build KLEE with LLVM 2.9, click here.

  1. Install dependencies: KLEE requires all the dependencies of LLVM, which are discussed here. In particular, you should install the following programs and libraries, listed below as Ubuntu packages:

    $ sudo apt-get install build-essential curl libcap-dev git cmake libncurses5-dev python-minimal python-pip unzip
    

    You will need gcc/g++ 4.8 or later installed on your system. For Ubuntu 12.04 and 13.04, you can follow the instructions here.

  2. Install LLVM 3.4: KLEE is built on top of LLVM; the first steps are to get a working LLVM installation. See Getting Started with the LLVM System for more information.

    NOTE: KLEE is currently tested on Linux x86-64, and might break on x86-32.

    If you are using a recent Ubuntu (≥ 12.04 and ≤ 15.10, e.g. 14.04 LTS) or Debian, we recommend you to use the LLVM packages provided by LLVM itself. Use LLVM Package Repository to add the appropriate line to your /etc/apt/sources.list. As an example, for Ubuntu 14.04, the following lines should be added:

    deb http://llvm.org/apt/trusty/ llvm-toolchain-trusty-3.4 main  
    deb-src http://llvm.org/apt/trusty/ llvm-toolchain-trusty-3.4 main
    

    Then add the repository key and install the 3.4 packages:

    $ wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key|sudo apt-key add -  
    $ sudo apt-get update  
    $ sudo apt-get install clang-3.4 llvm-3.4 llvm-3.4-dev llvm-3.4-tools  
    

    Finally, make sure llvm-config is in your path:

    That’s it for LLVM. If you want to install it manually, please refer to the official LLVM Getting Started documentation.

  3. Install constraint solver(s)

    KLEE supports multiple different constraint solvers. You must install at least one to build KLEE.

    • STP Historically KLEE was built around only this solver so support for this solver is the most stable. For build instructions see here.
    • Z3 Z3 support is much more recent addition to KLEE but is reasonably stable. You should use Z3 version >= 4.4. For build instructions see here.
    • metaSMT experimental For build instructions see here.
  4. (Optional) Build uclibc and the POSIX environment model: By default, KLEE works on closed programs (programs that don’t use any external code such as C library functions). However, if you want to use KLEE to run real programs you will want to enable the KLEE POSIX runtime, which is built on top of the uClibc C library.

    To build klee-uclibc run:

    $ git clone https://github.com/klee/klee-uclibc.git  
    $ cd klee-uclibc  
    $ ./configure --make-llvm-lib  
    $ make -j2  
    $ cd .. 
    

    NOTE: If you are on a different target (i.e., not i386 or x64), you will need to run make config and select the correct target. The defaults for the other uClibc configuration variables should be fine.

    To tell KLEE to use klee-uclibc and use the POSIX runtime pass -DENABLE_POSIX_RUNTIME=ON and -DKLEE_UCLIBC_PATH=<KLEE_UCLIBC_SOURCE_DIR> to CMake when configuring KLEE in step 9 where <KLEE_UCLIBC_SOURCE_DIR> is the absolute path to the cloned klee-uclibc git repository.

  5. (Optional) Get Google test sources:

    For unit tests we use the Google test libraries. If you don’t want to run the unit tests you can skip this step but you will need to pass -DENABLE_UNIT_TESTS=OFF to CMake when configuring KLEE in step 9.

    We depend on a version 1.7.0 right now so grab the sources for it.

    $ curl -OL https://github.com/google/googletest/archive/release-1.7.0.zip
    $ unzip release-1.7.0.zip
    

    This will create a directory called googletest-release-1.7.0.

  6. (Optional) Install lit:

    For testing the lit tool is used. If you LLVM from a build tree you can skip this step as the build system will try to use llvm-lit in the directory containing the LLVM binaries.

    If you don’t want to run the tests you can skip this step but you will need to pass -DENABLE_UNIT_TESTS=OFF and -DENABLE_SYSTEM_TESTS=OFF to CMake when configuring KLEE in step 9.

    $ pip install lit
    
  7. (Optional) Install tcmalloc:

    By default, KLEE uses malloc_info() to observe and to restrict its memory usage. Due to limitations of malloc_info(), the maximum limit is set to 2 GB. To support bigger limits, KLEE can use TCMalloc as an alternative allocator. It is thus necessary to install TCMalloc:

    $ sudo apt-get install libtcmalloc-minimal4 libgoogle-perftools-dev
    

    When configuring KLEE in step 9 pass -DENABLE_TCMALLOC=ON to CMake when configuring KLEE.

  8. Get KLEE source:

    $ git clone https://github.com/klee/klee.git
    
  9. Configure KLEE:

    KLEE must be built “out of source” so first make a binary build directory. You can create this where ever you like.

    $ mkdir klee_build_dir
    

    Now cd into the build directory and run CMake to configure KLEE where <KLEE_SRC_DIRECTORY> is the path to the KLEE git repository you cloned in step 8.

    $ cd klee_build_dir
    $ cmake <CMAKE_OPTIONS> <KLEE_SRC_DIRECTORY>
    

    <CMAKE_OPTIONS> are the configuration options. These are documented in README-CMake.md.

    For example if KLEE was being built with STP, the POSIX runtime, klee-uclibc and testing then the command line would look something like this

    cmake \
      -DENABLE_SOLVER_STP=ON \
      -DENABLE_POSIX_RUNTIME=ON \
      -DENABLE_KLEE_UCLIBC=ON \
      -DKLEE_UCLIBC_PATH=<KLEE_UCLIBC_SOURCE_DIR> \
      -DGTEST_SRC_DIR=<GTEST_SOURCE_DIR> \
      -DENABLE_SYSTEM_TESTS=ON \
      -DENABLE_UNIT_TESTS=ON \
      <KLEE_SRC_DIRECTORY>
    

    Where <KLEE_UCLIBC_SOURCE_DIR> is the absolute path the klee-uclibc source tree, <GTEST_SOURCE_DIR> is the absolute path to the Google Test source tree.

    NOTE: If LLVM is not found or you need a particular version to be used you can pass -DLLVM_CONFIG_BINARY=<LLVM_CONFIG_BINARY> to CMake where <LLVM_CONFIG_BINARY> is the absolute path to the relevant llvm-config binary. Similary KLEE needs a C and C++ compiler that can create LLVM bitcode that is compatible with the version of LLVM KLEE is using. If these are not detected automatically -DLLVMCC=<PATH_TO_CLANG> and -DLLVMCXX=<PATH_TO_CLANG++> can be passed to explicitly set these compilers where <PATH_TO_CLANG> is the absolute path to clang and <PATH_TO_CLANG++> is the absolute path to clang++.

  10. Build KLEE:

    From the klee_build_dir directory created in the previous step run.

    $ make
    
  11. (Optional) Run the main regression test suite

    If KLEE was configured with system tests enabled then you can run them like this.

    $ make systemtests
    

    If you want to invoke lit manually use:

    $ lit test/
    

    This way you can run individual tests or subsets of the suite:

    $ lit test/regression
    
  12. (Optional) Build and run the unit tests:

    If KLEE was configured with unit tests enabled then you can build and run the unit tests like this.

    $ make unittests
    
  13. You’re ready to go! Check the Tutorials page to try KLEE.

NOTE: For testing real applications (e.g. Coreutils), you may need to increase your system’s open file limit (ulimit -n). Something between 10000 and 999999 should work. In most cases, the hard limit will have to be increased first, so it is best to directly edit the /etc/security/limits.conf file.