This switches from a custom list of architectures to use the
target-lexicon crate.
- "set is_64bit=1; isa x86" is replaced with "target x86_64", and
similar for other architectures, and the `is_64bit` flag is removed
entirely.
- The `is_compressed` flag is removed too; it's no longer being used to
control REX prefixes on x86-64, ARM and Thumb are separate
architectures in target-lexicon, and we can figure out how to
select RISC-V compressed encodings when we're ready.
* Update to rustfmt-preview.
* Run "cargo fmt --all" with rustfmt 0.4.1.
rustfmt 0.4.1 is the latest release of rustfmt-preview available on the
stable channel.
* Fix a long line that rustfmt 0.4.1 can't handle.
* Remove unneeded commas left behind by rustfmt.
* Use FxHashMap instead of HashMap for better performance
* Replace the binary search in the coalescing pass with a FxHashMap
This speeds up coalescing by up to 16% and overall compilation by 9%
The dbg! macro expands to nothing in no_std mode, so variables that are
only used for debugging prompt unused variable warnings.
Also, allow unstable_features in no_std builds, since they use
feature(alloc), which is an unstable feature.
