Boogie

Boogie is an intermediate verification language (IVL), intended as a layer on which to build program verifiers for other languages. Several program verifiers have been built in this way, including the VCC and HAVOC verifiers for C and the verifiers for Dafny, Chalice, and Spec#. For a sample verifier for a toy language built on top of Boogie, see Forro.

Boogie is also the name of a tool. The tool accepts the Boogie language as input, optionally infers some invariants in the given Boogie program, and then generates verification conditions that are passed to an SMT solver. The default SMT solver is Z3.

Documentation

Here are some resources to learn more about Boogie. Be aware that some information might be incomplete or outdated.

• Documentation
• Language reference.
• This is Boogie 2 details many aspects of the Boogie IVL but is slightly out of date.

Getting help and contribute

You can ask questions and report issues on our issue tracker.

We are happy to receive contributions via pull requests.

Dependencies

Boogie requires .NET Core and a supported SMT solver (see below).

Installation

Boogie releases are packaged as a .NET Core global tool available at nuget.org. To install Boogie simply run:

$ dotnet tool install --global boogie

Building

To build Boogie run:

$ dotnet build Source/Boogie.sln

⚠️ There is currently a know build problem with .NET Core and GitVersionTask (see #213). The workaround is to set the environment variable MSBUILDSINGLELOADCONTEXT=1 and run dotnet build-server shutdown.

The compiled Boogie binary is Source/BoogieDriver/bin/${CONFIGURATION}/${FRAMEWORK}/BoogieDriver. Also, a NuGet package is placed in Source/BoogieDriver/bin/Debug/ which can be used for a local installation.

Backend SMT Solver

The default SMT solver for Boogie is Z3. Support for CVC4 and Yices2 is experimental.

By default, Boogie looks for an executable called z3|cvc4|yices2[.exe] in your PATH environment variable. If the solver executable is called differently on your system, use /proverOpt:PROVER_NAME=<exeName>. Alternatively, an explicit path can be given using /proverOpt:PROVER_PATH=<path>.

To learn how custom options can be supplied to the SMT solver (and more), call Boogie with /proverHelp.

Z3

The current test suite assumes version 4.8.8, but earlier and newer versions may also work.

CVC4 (experimental)

Call Boogie with /proverOpt:SOLVER=CVC4.

Yices2 (experimental)

Call Boogie with /proverOpt:SOLVER=Yices2 /useArrayTheory.

Works for unquantified fragments, e.g. arrays + arithmetic + bitvectors. Does not work for quantifiers, generalized arrays, datatypes.

Testing

Boogie has two forms of tests. Driver tests and unit tests

Driver tests

See the Driver test documentation

Unit tests

See the Unit test documentation

Versioning and Release Automation

The Bump workflow will create and push a new tag each time commits are pushed to the master branch (including PR merges). By default, the created tag increments the patch version number from the previous tag. For example, if the last tagged commit were v2.4.3, then pushing to master would tag the latest commit with v2.4.4. If incrementing minor or major number is desired instead of patch, simply add #minor or #major anywhere in the commit message. For instance:

Adding the next greatest feature. #minor

If the last tagged commit were v2.4.3, then pushing this commit would generate the tag v2.5.0.

For pull-request merges, if minor or major version increments are desired, the first line of the merge commit message can be changed to include #minor or #major.

Note that on each push to master, the following will happen:

• A travis build for master is triggered.
• The GitHub workflow is also triggered.
• Once the workflow pushes a new tag vX.Y.Z, another travis build for vX.Y.Z is triggered.
• The travis build for vX.Y.Z in Release configuration publishes releases to GitHub and NuGet.org.

License

Boogie is licensed under the MIT License (see LICENSE.txt).