Make garbage collection an async function
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This commit is similar to bytecodealliance#11442 and bytecodealliance#11460 except it's applied to the garbage collection phase of Wasmtime's GC. Specifically the functions that actually perform a GC are no longer duplicated across sync, async, and maybe async versions. There's only one "always async" version and the root-level crate entrypoints for sync versions assert that async support is disabled and then use the async version. Worth noting here is that GC suffers from a preexisting issue described in bytecodealliance#11409 where it's not sound how a `StoreOpaque` is widened to acquire a resource limiter. This commit seemingly makes the issue worse by adding a few more `unsafe` blocks, but they're all fundamentally doing the same thing as before. Fully solving this issue will require making memory/table creation an `async` function that takes the limiter as an argument. Doing this will require further refactoring/code movement so my goal is to effectively maintain the status quo, but in a slightly different location, and enable knocking out the `unsafe` in the future. In the meantime the previous `unsafe` block is "lifted higher up" so it's not quite so deep and should be easier to remove in the future.
bongjunj
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Oct 20, 2025
* Make garbage collection an `async` function This commit is similar to bytecodealliance#11442 and bytecodealliance#11460 except it's applied to the garbage collection phase of Wasmtime's GC. Specifically the functions that actually perform a GC are no longer duplicated across sync, async, and maybe async versions. There's only one "always async" version and the root-level crate entrypoints for sync versions assert that async support is disabled and then use the async version. Worth noting here is that GC suffers from a preexisting issue described in bytecodealliance#11409 where it's not sound how a `StoreOpaque` is widened to acquire a resource limiter. This commit seemingly makes the issue worse by adding a few more `unsafe` blocks, but they're all fundamentally doing the same thing as before. Fully solving this issue will require making memory/table creation an `async` function that takes the limiter as an argument. Doing this will require further refactoring/code movement so my goal is to effectively maintain the status quo, but in a slightly different location, and enable knocking out the `unsafe` in the future. In the meantime the previous `unsafe` block is "lifted higher up" so it's not quite so deep and should be easier to remove in the future. * Review comments * Fix configured build * More configured build fixes
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This commit is similar to #11442 and #11460 except it's applied to the
garbage collection phase of Wasmtime's GC. Specifically the functions
that actually perform a GC are no longer duplicated across sync, async,
and maybe async versions. There's only one "always async" version and
the root-level crate entrypoints for sync versions assert that async
support is disabled and then use the async version.
Worth noting here is that GC suffers from a preexisting issue described
in #11409 where it's not sound how a
StoreOpaqueis widened to acquirea resource limiter. This commit seemingly makes the issue worse by
adding a few more
unsafeblocks, but they're all fundamentally doingthe same thing as before. Fully solving this issue will require making
memory/table creation an
asyncfunction that takes the limiter as anargument. Doing this will require further refactoring/code movement so
my goal is to effectively maintain the status quo, but in a slightly
different location, and enable knocking out the
unsafein the future.In the meantime the previous
unsafeblock is "lifted higher up" soit's not quite so deep and should be easier to remove in the future.