Wasmtime GitHub notifications bot (May 05 2025 at 14:33): Wasmtime GitHub notifications bot (May 05 2025 at 14:33):alexcrichton opened PR #10727 from alexcrichton:compile-away-pulley-simd to bytecodealliance:main:
This commit adds a new feature to Pulley which is used to reduce the compiled code size of the interpreter itself by disabling SIMD opcode interpretation at compile-time. The goal here is to be low-impact on Pulley itself to avoid needing
#[cfg]all over the place and to additionally avoid the need to redesign Pulley's opcode macro for use in various parts of Wasmtime.Methods are annotated with a custom macro in the interpreter which registers a
#[cfg]that either does the listed implementation or switches to an implementation that emits a trap if executed. This means that it's safe to execute mismatched code where SIMD was enabled at compile time but disabled at runtime, it just means the semantics may be a bit surprising to debug.Note that this SIMD is still enabled by default, and an explicit
--cfgviaRUSTFLAGSis required to compile-out the SIMD support. Cargo features aren't a great fit for this sort of feature so an explicit flag is used.<!--
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Wasmtime GitHub notifications bot (May 05 2025 at 14:33):alexcrichton requested wasmtime-default-reviewers for a review on PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 14:33):alexcrichton requested wasmtime-core-reviewers for a review on PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 14:33):alexcrichton requested pchickey for a review on PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 14:36):alexcrichton updated PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 15:45):github-actions[bot] commented on PR #10727:
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Wasmtime GitHub notifications bot (May 05 2025 at 16:06):alexcrichton commented on PR #10727:
I gathered some numbers in https://github.com/google/wasefire/issues/458#issuecomment-2851490398 and for that particular embedding this is a 10% reduction in text size when compiled with
--releaseand a 5% reduction in text size when compiled withopt-level=z
Wasmtime GitHub notifications bot (May 05 2025 at 16:07):alexcrichton edited a comment on PR #10727:
I gathered some numbers in https://github.com/google/wasefire/issues/458#issuecomment-2851490398 and for that particular embedding this is a 10% reduction in text size (44k) when compiled with
--releaseand a 5% reduction in text size (14k) when compiled withopt-level=z
Wasmtime GitHub notifications bot (May 05 2025 at 16:14):pchickey submitted PR review.
Wasmtime GitHub notifications bot (May 05 2025 at 17:56):alexcrichton updated PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 17:56):alexcrichton has enabled auto merge for PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 19:40):alexcrichton updated PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 20:20):alexcrichton updated PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 20:22):alexcrichton has enabled auto merge for PR #10727.
Wasmtime GitHub notifications bot (May 05 2025 at 20:54):alexcrichton merged PR #10727.
Last updated: Dec 06 2025 at 06:05 UTC