Isabelle-LLVM

Isabelle-LLVM is a verification framework for Isabelle/HOL that targets LLVM as backend. The main features are:

• Shallowly embedded semantics of fragment of LLVM
• Code generator, to export LLVM code
• Generation of header files for interfacing the code from C/C++
• Separation logic based VCG
• Support for stepwise refinement based verification

News

• July 2021: ISASAT, a fully verified SAT solver that uses Isabelle-LLVM, has won the 2021 EDA Fixed CNF Encoding Race.
• June 2021: released version 2.0. New features:
  • support of arbitrary structures, and pointers to structure itself (required for, e.g., linked lists)
  • faster export_llvm for big code
• Updated to work with new Isabelle 2021 version

Getting Started

You can browse the theories or download the files.

Warning: the .thy files in the download are best viewed with the Isabelle/HOL IDE.

Git Repository

The project is hosted on github https://github.com/lammich/isabelle_llvm

Starting Points for Browsing

Here are some default starting points for browsing the theories

Verified Algorithms

Introsort

PDQ Sort

Knuth Morris Pratt String Search

Isabelle-LLVM

IICF (Isabelle-LLVM + Refinement Framework + Collection Framework)

Shallow Embedding of LLVM Semantics

Prerequisites

• To compile the LLVM code: Working installation of LLVM version >= 6.0.0.
• To compile the functional code: An MLton compiler version >= 20100608.
• To re-check the proofs: Working installation of Isabelle/HOL with the Archive of Formal Proofs installed as as described on https://www.isa-afp.org/using.shtml. We require version = Isabelle-2021, which, at the time of writing, is the current version.
• To run the regression tests: Valgrind version >= 3.0.0

Compiling and running benchmarks

To compile and run the benchmarks

cd benchmarks
./bench_bs.sh -r
./bench_kmp.sh -r
cd sorting
make run

This will run the binary search, KMP, and sorting benchmarks. Warning: We have only tested this on a Linux x86_64 platform so far. We do not (yet) know how LLVM will digest our code on other platforms.

Re-Checking the Proofs

To re-check the proofs, run

  cd thys 
  isabelle build -D.

Here, isabelle must refer to /your/path/to/Isabelle2021/bin/isabelle from your Isabelle installation. This will invoke Isabelle to check all proofs and re-generate the exported code.

Regression Test Script

To run a quick regression test script

  cd regression
  make

This will re-check the proofs, export a few example programs, link them with C wrappers, and execute them under Valgrind’s memcheck, to detect ABI problems with header file generation and interfacing exported code from C.

Talks and Publications

IJCAR’2020 Paper Slides

ITP’2019 Paper Slides

May 2021 Talk in Enschede

Short Presentation of the Isabelle Refinement Framework

Mar 2020 Talk in Enschede

Dec 2019 Talk in Rennes

Old Versions

Isabelle-LLVM 1.0 for Isabelle-2020

Isabelle-LLVM 1.1 for Isabelle-2021