Duet is a static analysis tool designed for analyzing concurrent programs.

Duet depends on several software packages. The following dependencies need to be installed manually.

• opam (version >= 2, with OCaml >= 4.10 & native compiler)
  • If you have an older version of opam installed, you can install opam2 using opam install opam-devel
• GMP and MPFR
• NTL: number theory library
• Java
• Python
• Libffi
• Pkg-config
• Autoconf
• Libtool
• Flint
• Arb

On Ubuntu, you can install these packages with:

 sudo apt-get install opam libgmp-dev libmpfr-dev libntl-dev default-jre python python3-distutils python3-lib2to3 libffi-dev pkg-config autoconf libtool libflint-dev libflint-arb-dev

On MacOS, you can install these packages (except Java) with:

 brew install opam gmp mpfr ntl python libffi pkg-config autoconf libtool

Next, add the sv-opam OPAM repository, and install the rest of duet's dependencies. These are built from source, so grab a coffee — this may take a long time.

 opam remote add sv https://github.com/zkincaid/sv-opam.git#modern
 opam install ocamlbuild ocamlfind zarith ocamlgraph batteries ppx_deriving ounit menhir ctypes-foreign
 opam install cil apron ntl normalizffi z3 faugere arbduet

After Duet's dependencies are installed, it can be built as follows:

 ./configure
 make

Duet's makefile has the following targets:

• make: Build duet
• make srk: Build the ark library and test suite
• make apak: Build the apak library and test suite
• make doc: Build documentation
• make test: Run test suite

There are three main program analyses implemented in Duet:

• Data flow graphs: duet.native -coarsen FILE
• Proof spaces: duet.native -proofspace FILE
• Compositional recurrence analysis: duet.native -cra FILE

Duet supports two file types (and guesses which to use by file extension): C programs (.c), Boolean programs (.bp).

By default, Duet checks user-defined assertions, which are specified by the built-in function __VERIFIER_assert. Alternatively, it can also instrument assertions as follows:

duet.native -check-array-bounds -check-null-deref -coarsen FILE

The -coarsen flag implements an invariant generation procedure for multi-threaded programs with an unbounded number of threads. The analysis is described in

• Azadeh Farzan and Zachary Kincaid: Verification of Parameterized Concurrent Programs By Modular Reasoning about Data and Control. POPL 2012.

The -proofspace flag implements a software model checking procedure for multi-threaded programs with an unbounded number of threads. The procedure is described in

• Azadeh Farzan, Zachary Kincaid, Andreas Podelski: Proof Spaces for Unbounded Parallelism. POPL 2015.

The -cra flag is an invariant generation procedure for sequential programs. The analysis is described in

• Azadeh Farzan and Zachary Kincaid: Compositional Recurrence Analysis. FMCAD 2015.
• Zachary Kincaid, John Cyphert, Jason Breck, Thomas Reps: Non-Linear Reasoning For Invariant Synthesis. POPL 2018.

Typically, it is best to run CRA with -cra-split-loops. By default, the -cra runs the analysis as described in POPL'18. The FMCAD'15 analysis can be run by setting the -cra-no-matrix flag.

Several other analyses are available using the -cra-X family of flags (see ./duet.exe --help for a full list).

• -cra-prsd: Zachary Kincaid, Jason Breck, John Cyphert, and Tom Rep: Closed Forms for Numerical Loops. POPL 2019.
• -cra-vas and -cra-vass: Jake Silverman and Zachary Kincaid: Loop Summarization with Rational Vector Addition Systems. CAV 2019.
• -lirr: Zachary Kincaid, Nicolas Koh, Shaowei Zhu: When Less is More: Consequence-finding in a Weak Theory of Arithmetic. To appear in POPL 2023.

The interprocedural variant is described in

• Zachary Kincaid, Jason Breck, Ashkan Forouhi Boroujeni, Thomas Reps: Compositional Recurrence Analysis Revisited. PLDI 2017.

is available in the Newton-ark2 branch of this repository. Build instructions to come.

The -termination flag implements algebraic termination analysis, as described in

• Shaowei Zhu, Zachary Kincaid: Termination Analysis Without the Tears. PLDI 2021.
• Reflections on Termination of Linear Loops: Reflections on Termination of Linear Loops. CAV 2021.

By default, the termination analyzer uses a portfolio of different approaches for proving termination, which can be selectively disabled using the -termination-no-X family of flags (see ./duet.exe --help for a full list). Most of the -cra-X family of flags are also compatible with -termination.

Duet is split into several packages:

• srk

  Symbolic reasoning kit. This is a high-level interface over Z3 and Apron. Most of the work of compositional recurrence analysis lives in srk.

• pa

  Predicate automata library.

• duet

  Implements program analyses, frontends, and anything programming-language specific.