IRIS COQ DEVELOPMENT

This is the Coq development of the Iris Project, which includes MoSeL, a general proof mode for carrying out separation logic proofs in Coq.

A LaTeX version of the core logic definitions and some derived forms is available in docs/iris.tex. A compiled PDF version of this document is available online.

Building Iris

Prerequisites

This version is known to compile with:

• Coq 8.7.1 / 8.7.2 / 8.8.0 / 8.8.1
• A development version of std++

For a version compatible with Coq 8.6, have a look at the iris-3.1 branch. If you need to work with Coq 8.5, please check out the iris-3.0 branch.

Working with Iris

To use Iris in your own proofs, we recommend you install Iris via opam (1.2.2 or newer). To obtain the latest stable release, you have to add the Coq opam repository:

opam repo add coq-released https://coq.inria.fr/opam/released

To obtain a development version, also add the Iris opam repository:

opam repo add iris-dev https://gitlab.mpi-sws.org/FP/opam-dev.git

Either way, you can now do opam install coq-iris. To fetch updates later, run opam update && opam upgrade. However, notice that we do not guarnatee backwards-compatibility, so upgrading Iris may break your Iris-using developments.

Working on Iris

To work on Iris itself, you need to install its build-dependencies. Again we recommend you do that with opam (1.2.2 or newer). This requires the following two repositories:

opam repo add coq-released https://coq.inria.fr/opam/released
opam repo add iris-dev https://gitlab.mpi-sws.org/FP/opam-dev.git

Once you got opam set up, run make build-dep to install the right versions of the dependencies.

Run make -jN to build the full development, where N is the number of your CPU cores.

To update Iris, do git pull. After an update, the development may fail to compile because of outdated dependencies. To fix that, please run opam update followed by make build-dep.

Directory Structure

• The folder algebra contains the COFE and CMRA constructions as well as the solver for recursive domain equations.
• The folder base_logic defines the Iris base logic and the primitive connectives. It also contains derived constructions that are entirely independent of the choice of resources.
  • The subfolder lib contains some generally useful derived constructions. Most importantly, it defines composeable dynamic resources and ownership of them; the other constructions depend on this setup.
• The folder program_logic specializes the base logic to build Iris, the program logic. This includes weakest preconditions that are defined for any language satisfying some generic axioms, and some derived constructions that work for any such language.
• The folder bi contains the BI++ laws, as well as derived connectives, laws and constructions that are applicable for general BIS.
• The folder proofmode contains MoSeL, which extends Coq with contexts for intuitionistic and spatial BI++ assertions. It also contains tactics for interactive proofs. Documentation can be found in ProofMode.md.
• The folder heap_lang defines the ML-like concurrent heap language
  • The subfolder lib contains a few derived constructions within this language, e.g., parallel composition. For more examples of using Iris and heap_lang, have a look at the Iris Examples.
• The folder tests contains modules we use to test our infrastructure. Users of the Iris Coq library should not depend on these modules; they may change or disappear without any notice.

Case Studies

The following is a (probably incomplete) list of case studies that use Iris, and that should be compatible with this version:

• Iris Examples is where we collect miscellaneous case studies that do not have their own repository.
• LambdaRust is a Coq formalization of the core Rust type system.
• iGPS is a logic for release-acquire memory.
• Iris Atomic is an experimental formalization of logically atomic triples in Iris.

Notes for Iris Developers

• Information on how to set up your editor for unicode input and output is collected in Editor.md.
• The Iris Proof Mode (IPM) / MoSeL is documented at ProofMode.md.
• Naming conventions are documented at Naming.md.

How to update the std++ dependency

• Do the change in std++, push it.
• Wait for CI to publish a new std++ version on the opam archive, then run opam update iris-dev.
• In Iris, change the opam file to depend on the new version.
• Run make build-dep (in Iris) to install the new version of std++. You may have to do make clean as Coq will likely complain about .vo file mismatches.

How to write/update test cases

The files in tests/ are test cases. Each of the .v files comes with a matching .ref file containing the expected output of coqc. Adding Show. in selected places in the proofs makes coqc print the current goal state. This is used to make sure the proof mode prints goals and reduces terms the way we expect it to. You can run MAKE_REF=1 make to re-generate all the .ref files; this is useful after adding or removing Show. from a test. If you do this, make sure to check the diff for any unexpected changes in the output!