Wasmtime GitHub notifications bot (Feb 24 2026 at 23:36): Wasmtime GitHub notifications bot (Feb 24 2026 at 23:36):cfallin opened PR #12663 from cfallin:debugging-the-module-registration-single-step-dance to bytecodealliance:main:
We currently do a store-wide state-change on all registered modules when the "single stepping" flag changes, patching in or out all breakpoints. However, this design didn't account for modules registered with the store after single-stepping is enabled (and new modules may be registered any time an instantiation occurs). In particular this is problematic when a debugger, e.g., sets the single-step flag right at the beginning of execution of a "host main function" that calls Wasm, before the main instantiation occurs.
This PR threads through the breakpoint state in the registration path, with the narrow waist at
ModuleRegistry::registerwhich is the only place where modules are added to theLoadedCode.<!--
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Wasmtime GitHub notifications bot (Feb 24 2026 at 23:36):cfallin requested fitzgen for a review on PR #12663.
Wasmtime GitHub notifications bot (Feb 24 2026 at 23:36):cfallin requested wasmtime-core-reviewers for a review on PR #12663.
Wasmtime GitHub notifications bot (Feb 24 2026 at 23:36):cfallin unassigned fitzgen from PR #12663 Debugging: apply single-stepping patches to modules instantiated after setting changes..
Wasmtime GitHub notifications bot (Feb 24 2026 at 23:36):cfallin requested alexcrichton for a review on PR #12663.
Wasmtime GitHub notifications bot (Feb 25 2026 at 00:01):alexcrichton submitted PR review.
Wasmtime GitHub notifications bot (Feb 25 2026 at 00:01):alexcrichton added PR #12663 Debugging: apply single-stepping patches to modules instantiated after setting changes. to the merge queue
Wasmtime GitHub notifications bot (Feb 25 2026 at 00:25):alexcrichton merged PR #12663.
Wasmtime GitHub notifications bot (Feb 25 2026 at 00:25):alexcrichton removed PR #12663 Debugging: apply single-stepping patches to modules instantiated after setting changes. from the merge queue
Last updated: Mar 23 2026 at 16:19 UTC