build: support rv64im zkVM target via lower-atomic pass#27
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Taking over the rv64im effort from @lazovicff PR #26. Implemented the lower-atomic LLVM pass as suggested by @kevaundray in issue #4 |
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| The `stateless` crate is `#![no_std]` compatible and builds for RISC-V targets (`riscv32imac-unknown-none-elf`), making it suitable for use in zkVM environments. | ||
| The `stateless` crate is `#![no_std]` compatible and builds for the 64-bit RISC-V target | ||
| (`riscv64im-unknown-none-elf`), making it suitable for use in zkVM environments. |
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this reads as if users can pass the built-in --target riscv64im-unknown-none-elf, but that target still fails here because alloc::sync is cfg-gated off
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| target=targets/riscv64im-unknown-none-elf.json | ||
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| cmd=(cargo +stable build --no-default-features --target "$target" -p stateless) | ||
| export RUSTFLAGS="-C passes=lower-atomic" |
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the build still passes if this flag is removed, but the resulting rlibs contain __atomic_* references
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Great catches. Thanks! I just pushed a commit that updates the README and adds a warning comment above the RUSTFLAGS export. |
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i believe this is ready to merge as-is
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addresses #4
Adds support for compiling to
rv64im(without atomics) by utilizing the LLVMlower-atomicpass.riscv64im-unknown-none-elf.json(features:+m).RUSTFLAGS="-C passes=lower-atomic"to lower atomics in upstream dependencies (safe for single-threaded zkVMs).check_no_std.shand CI to usenightlyand-Zbuild-std=core,alloc.