We long term want to support compilation of livesplit-core with just core + alloc. You'd provide your own time source as some global handler but other than that everything should mostly just work as we already see with wasm32-unknown-unknown. However most crates that we depend on probably don't support this yet, so that's probably going to be a lot of Pull Requests.

Update

All the crates we need are sufficiently patched on forked branches. We just need to do a bunch of PRs now. Here's the super fancy results, with LiveSplit One being rendered within the world of Wind Waker:

https://twitter.com/CryZe107/status/1158444993549414401

Status

Basic Support

Required

• base64 - Released as 0.11.0, PR is merged Implement Support for no_std marshallpierce/rust-base64#111
• derive_more - Released as 0.99.0, PR is "merged" Fix no_std support JelteF/derive_more#84
• odds
• ordered-float
• palette - Released as 0.5.0, PR is merged Fix no_std build failure Ogeon/palette#138
• serde
• snafu - Released as 0.6.0, PR is merged Implement Support for no_std shepmaster/snafu#138
• hashbrown - Released as 0.6.0 (There might be some bug though ahash still doesn't work on no_std for me tkaitchuck/aHash#17)
• libm

Polyfilled (not required, but would be good to get rid of the polyfill)

• unicase - Released as 2.6.0, PR is merged Implement no_std support seanmonstar/unicase#34
• indexmap - Released as 1.3.0, PR is merged Support building without libstd indexmap-rs/indexmap#106 (but serde support is missing serde feature is incompatible with no_std indexmap-rs/indexmap#109)
• chrono - Released as 0.4.10, PR is merged Implement Support for no_std chronotope/chrono#341

Optional

• byteorder - Some IO.
• image - Too much IO.
• livesplit-hotkey - We don't really need it, but we can easily provide an empty hotkey implementation.
• livesplit-title-abbreviations
• parking_lot - Not really needed on no_std, does too many OS things.
• quick-xml - Too much IO.
• serde_json - Too much IO, but there is a PR: No_std support serde-rs/json#516
• utf-8 - Uses IO.

Rendering

• euclid - Released as 0.20.6, PR is merged Implement actual support for no_std servo/euclid#372
  • num-traits - Released as 0.2.9, PR is merged Revive Float+Real in no_std thanks to libm rust-num/num-traits#99
• ttf-parser
• rustybuzz - PR is is merged, needs a release: Implement no_std support harfbuzz/rustybuzz#30
• lyon - Needs a PR: https://github.com/CryZe/lyon/tree/no-std
  • depends on euclid
  • sid - Released as 0.6.1, PR is merged Implement Support for no_std nical/sid#2
• rusttype - Released as 0.8.0, PR is merged https://gitlab.redox-os.org/redox-os/rusttype/merge_requests/145
  • stb_truetype - Released as 0.3.0, PR is merged https://gitlab.redox-os.org/redox-os/stb_truetype-rs/merge_requests/31
• smallvec - Released as 0.6.11, PR is merged alloc is now stable servo/rust-smallvec#159

Software Rendering

• tiny-skia - Needs a PR
• euc - Released as 0.5.0, PR is merged Implement proper no_std support zesterer/euc#12
  • vek - Released as 0.10.0, PR is merged Implement Support for no_std yoanlcq/vek#41
    • depends on num-traits