Stream: git-wasmtime

Topic: wasmtime / issue #11847 Guest debugging: track precise GC...

Wasmtime GitHub notifications bot (Oct 13 2025 at 17:52):

cfallin opened issue #11847:

(Followup from this discussion)

In the instrumentation-based guest debugging support, we have a separate FrameValType at the environ level that is used in the metadata to describe types of values. It is a mirror of the runtime-side types, but is simpler as it doesn't track precise GC types. We'll need to plumb through ModuleInternedTypeIndexes and then translate those via the type registry at runtime to support:

• Mutation, because we need to check that an updated value for a local/stack slot is of a compatible type
• An API that allows querying the precise type of the slot at runtime

Wasmtime GitHub notifications bot (Oct 13 2025 at 20:39):

fitzgen commented on issue #11847:

FWIW, we will need this for typed function references as well, not just GC types.

We really don't want to be able to mutate a (local (ref null $my_func_type)) such that a function reference of an incompatible type is stored in that local, and then we call_ref it and get UB.

Wasmtime GitHub notifications bot (Oct 23 2025 at 16:39):

fitzgen added the wasmtime:debugging label to Issue #11847.

Last updated: Dec 06 2025 at 07:03 UTC