feat: add wasm32 single-thread fallback for threadpool#64
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URDJMK wants to merge 2 commits intofilecoin-project:masterfrom
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feat: add wasm32 single-thread fallback for threadpool#64URDJMK wants to merge 2 commits intofilecoin-project:masterfrom
URDJMK wants to merge 2 commits intofilecoin-project:masterfrom
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On wasm32 targets, OS thread spawning is not supported. This adds a single-threaded fallback that executes all operations sequentially on the main thread when compiled for wasm32-unknown-unknown. Changes: - threadpool.rs: split into native (yastl Pool) and wasm (WasmScope, WasmPool) modules, conditionally compiled via cfg(target_arch) - multiexp.rs: use WasmScope on wasm32 instead of yastl::Scope - WasmPool provides scoped() for fft.rs compatibility - WasmScope provides execute() matching yastl::Scope API - Worker API unchanged — callers don't need modification This enables bellperson Groth16 proof generation in the browser via WebAssembly.
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Summary
Add wasm32-unknown-unknown support to ec-gpu-gen's threadpool module.
On wasm32 targets, OS thread spawning (
std::thread::spawn) panics because WASM does not support native threads. This PR adds a single-threaded fallback that executes all operations sequentially on the main thread when compiled forwasm32-unknown-unknown.Motivation
bellperson uses ec-gpu-gen for multi-exponentiation and FFT operations. While bellperson itself compiles to WASM (blst has built-in wasm32 support), it panics at runtime when
yastl::Pool::new()tries to spawn worker threads. This makes Groth16 proof generation in the browser impossible.With this change, bellperson can generate Groth16 proofs in browser WASM — single-threaded but fully functional. This enables client-side ZK proof generation for privacy protocols without requiring a server-side prover.
Changes
threadpool.rs: Split intonative(yastl Pool, multi-threaded) andwasm(WasmScope/WasmPool, single-threaded) modules via#[cfg(target_arch = "wasm32")]multiexp.rs: UseWasmScopeon wasm32 instead ofyastl::ScopeWasmPoolprovidesscoped()for fft.rs compatibilityWasmScopeprovidesexecute()matchingyastl::ScopeAPIWorkerAPI unchanged — downstream callers don't need modificationTesting
Tested with bellperson 0.26 compiled to wasm32-unknown-unknown via wasm-pack. Groth16 proof generation and verification confirmed working in Chrome browser.