======================= Cretonne Code Generator ======================= Cretonne is a low-level retargetable code generator. It translates a `target-independent intermediate representation `_ into executable machine code. .. image:: https://readthedocs.org/projects/cretonne/badge/?version=latest :target: https://cretonne.readthedocs.io/en/latest/?badge=latest :alt: Documentation Status .. image:: https://travis-ci.org/cretonne/cretonne.svg?branch=master :target: https://travis-ci.org/cretonne/cretonne :alt: Build Status .. image:: https://badges.gitter.im/cretonne/cretonne.svg :target: https://gitter.im/cretonne/Lobby/~chat :alt: Gitter chat For more information, see `the documentation `_. Status ------ Cretonne currently supports enough functionality to run a wide variety of programs, including all the functionality needed to execute WebAssembly MVP functions, although it needs to be used within an external WebAssembly embedding to be part of a complete WebAssembly implementation. The x86-64 backend is currently the most complete and stable; other architectures are in various stages of development. Cretonne currently supports the System V AMD64 ABI calling convention used on many platforms, but does not yet support the Windows x64 calling convention. The performance of code produced by Cretonne is not yet impressive, though we have plans to fix that. The core codegen crates have minimal dependencies, support `no_std <#building-with-no-std>`_ mode, and do not require any host floating-point support. Cretonne does not yet perform mitigations for Spectre or related security issues, though it may do so in the future. It does not currently make any security-relevant instruction timing guarantees. It has seen a fair amount of testing and fuzzing, although more work is needed before it would be ready for a production use case. Cretonne's APIs are not yet stable. Cretonne currently supports Rust 1.22.1 and later. We intend to always support the latest *stable* Rust. And, we currently support the version of Rust in the latest Ubuntu LTS, although whether we will always do so is not yet determined. Cretonne requires Python 2.7 or Python 3 to build. Planned uses ------------ Cretonne is designed to be a code generator for WebAssembly, but it is general enough to be useful elsewhere too. The initial planned uses that affected its design are: 1. `WebAssembly compiler for the SpiderMonkey engine in Firefox `_. 2. `Backend for the IonMonkey JavaScript JIT compiler in Firefox `_. 3. `Debug build backend for the Rust compiler `_. Building Cretonne ----------------- Cretonne is using the Cargo package manager format. First, ensure you have installed a current stable rust (stable, beta, and nightly should all work, but only stable and beta are tested consistently). Then, change the working directory to your clone of cretonne and run:: cargo build This will create a *target/debug* directory where you can find the generated binary. To build the optimized binary for release:: cargo build --release You can then run tests with:: ./test-all.sh Building with `no_std` ---------------------- The following crates support `no_std`: - `cretonne-entity` - `cretonne-codegen` - `cretonne-frontend` - `cretonne-native` - `cretonne-wasm` - `cretonne-module` - `cretonne-simplejit` - `cretonne` To use `no_std` mode, disable the `std` feature and enable the `core` feature. This currently requires nightly rust. For example, to build `cretonne-codegen`: .. code-block:: sh cd lib/codegen cargo build --no-default-features --features core Or, when using `cretonne-codegen` as a dependency (in Cargo.toml): .. code-block:: [dependency.cretonne-codegen] ... default-features = false features = ["core"] `no_std` support is currently "best effort". We won't try to break it, and we'll accept patches fixing problems, however we don't expect all developers to build and test `no_std` when submitting patches. Accordingly, the `./test-all.sh` script does not test `no_std`. There is a separate `./test-no_std.sh` script that tests the `no_std` support in packages which support it. It's important to note that cretonne still needs liballoc to compile. Thus, whatever environment is used must implement an allocator. Also, to allow the use of HashMaps with `no_std`, an external crate called `hashmap_core` is pulled in (via the `core` feature). This is mostly the same as `std::collections::HashMap`, except that it doesn't have DOS protection. Just something to think about. Building the documentation -------------------------- To build the Cretonne documentation, you need the `Sphinx documentation generator `_:: $ pip install sphinx sphinx-autobuild sphinx_rtd_theme $ cd cretonne/docs $ make html $ open _build/html/index.html We don't support Sphinx versions before 1.4 since the format of index tuples has changed.