Document panics from using CM async machinery when CM async is not enabled #12393
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@fitzgen are you ok if I take over this PR? I'm implementing more refactorings related to #12377 (comment) and it'll probably be easier to lump in the documentation updates at the same time |
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Sure thing, go for it |
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This commit is an extension/refactor of bytecodealliance#12377 and bytecodealliance#12379. Notably this decouples the runtime behavior of Wasmtime from enabled/disabled WebAssembly proposals. This enables the `wasmtime serve` subcommand, for example, to continue to disallow component-model-async by default but continue to use `*_concurrent` under the hood. Specifically a new `Config::concurrency_support` knob is added. This is plumbed directly through to `Tunables` and takes over the preexisting `component_model_concurrency` field. This field configures whether tasks/etc are enabled at runtime for component-y things. The default value of this configuration option is the same as `cfg!(feature = "component-model-async")`, and this field is required if component-model-async wasm proposals are enabled. It's intended that eventually this'll affect on-by-default wasm features in Wasmtime depending if the support is compiled in. This results in a subtle shift in behavior where component-model-async concurrency is used by default now because the feature is turned on by default, even though the wasm features are off-by-default. This required adjusting a few indices expected in runtime tests due to tasks/threads being allocated in index spaces. Finally, this additionally denies access at runtime to `Linker::*_concurrent` when concurrent support is disabled as otherwise the various runtime data structures won't be initialized and panics will happen. Closes bytecodealliance#12393
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* Document panics from using CM async machinery when CM async is not enabled * Refactor how concurrency support is enabled in a `Store` This commit is an extension/refactor of #12377 and #12379. Notably this decouples the runtime behavior of Wasmtime from enabled/disabled WebAssembly proposals. This enables the `wasmtime serve` subcommand, for example, to continue to disallow component-model-async by default but continue to use `*_concurrent` under the hood. Specifically a new `Config::concurrency_support` knob is added. This is plumbed directly through to `Tunables` and takes over the preexisting `component_model_concurrency` field. This field configures whether tasks/etc are enabled at runtime for component-y things. The default value of this configuration option is the same as `cfg!(feature = "component-model-async")`, and this field is required if component-model-async wasm proposals are enabled. It's intended that eventually this'll affect on-by-default wasm features in Wasmtime depending if the support is compiled in. This results in a subtle shift in behavior where component-model-async concurrency is used by default now because the feature is turned on by default, even though the wasm features are off-by-default. This required adjusting a few indices expected in runtime tests due to tasks/threads being allocated in index spaces. Finally, this additionally denies access at runtime to `Linker::*_concurrent` when concurrent support is disabled as otherwise the various runtime data structures won't be initialized and panics will happen. Closes #12393 * Add a `-Wconcurrency-support` CLI flag Used to update disas tests to show that, when disabled, old codegen quality is preserved * Ungate `Config` flag * Review comments --------- Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>
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