2bd03256b3
* Make regalloc2 `#![no_std]` This crate doesn't require any features from the standard library, so it can be made `no_std` to allow it to be used in environments that can't use the Rust standard library. This PR mainly performs the following mechanical changes: - `std::collections` is replaced with `alloc::collections`. - `std::*` is replaced with `core::*`. - `Vec`, `vec!`, `format!` and `ToString` are imported when needed since they are no longer in the prelude. - `HashSet` and `HashMap` are taken from the `hashbrown` crate, which is the same implementation that the standard library uses. - `FxHashSet` and `FxHashMap` are typedefs in `lib.rs` that are based on the `hashbrown` types. The only functional change is that `RegAllocError` no longer implements the `Error` trait since that is not available in `core`. Dependencies were adjusted to not require `std` and this is tested in CI by building against the `thumbv6m-none-eabi` target that doesn't have `std`. * Add the Error trait impl back under a "std" feature
regalloc2: another register allocator
This is a register allocator that started life as, and is about 50% still, a port of IonMonkey's backtracking register allocator to Rust. In many regards, it has been generalized, optimized, and improved since the initial port.
In addition, it contains substantial amounts of testing infrastructure (fuzzing harnesses and checkers) that does not exist in the original IonMonkey allocator.
See the design overview for (much!) more detail on how the allocator works.
License
This crate is licensed under the Apache 2.0 License with LLVM
Exception. This license text can be found in the file LICENSE.
Parts of the code are derived from regalloc.rs: in particular,
src/checker.rs and src/domtree.rs. This crate has the same license
as regalloc.rs, so the license on these files does not differ.