Introduce the javy-profiler-lib crate#1208
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Part of bytecodealliance#1206 This is the first change towards a Wasm-native profiler for Javy generated modules. Particularly, this change introduces the profiler library crate, which will be used as a user-provided library by [Whamm](https://github.com/ejrgilbert/whamm). The library will be compiled to wasm32-wasip1 and will have the following responsibilities: * Detecting the Wasm function in the target app holding the interpreter dispatch loop * Detecting the byte-load provenance used to dispatch to the next opcode (index argument to `br_table`) * Holing the necessary state to construct the JS execution trace * Generating the execution trace output for analysis This change includes, point 1 and 2. The remaining functionality will be done in separate pull requests. Note that, as stated in the issue above, this work is deemed experimental for the time being and this crate will be included through a feature flag when added to the CLI.
saulecabrera
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May 12, 2026
| use state::State; | ||
| use std::sync::LazyLock; | ||
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| // TODO: Passing empty bytes is temporary. Whamm currently does not |
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I am currently working on adding support for this upstream.
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Hmm, taking a look at the clippy failures, I was not able to repro locally. |
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Part of #1206
This is the first change towards a Wasm-native profiler for Javy generated modules.
Particularly, this change introduces the profiler library crate, which will be used as a user-provided library by
Whamm.
The library will be compiled to wasm32-wasip1 and will have the following responsibilities:
br_table)This change includes, point 1 and 2. The remaining functionality will be done in separate pull requests.
Note that, as stated in the issue above, this work is deemed experimental for the time being and this crate will be included through a feature flag when added to the CLI.
javy-plugin-apiif the QuickJS bytecode has changed.javy-cli,javy-plugin, andjavy-plugin-processingdo not require updating CHANGELOG files.