Support multiple heterogeneous backends at the same time #5243
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Adds a function to retrieve a unique identifier (backed by an `AtomicU64`) for the top-level `Engine` type. The `id` is saved in the `Engine` struct itself rather than types down the line. This fits better with the current structure of the `sys` rt engines, which are defined in the `wasmer_compiler` crate.
…r-with-native-ones
| impl Default for RuntimeEngine { | ||
| #[allow(unreachable_code)] | ||
| fn default() -> Self { | ||
| #[cfg(feature = "sys")] |
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One thing is enabling a sys runtime, and other a default runtime being sys. I think we need a new feature that let you choose the default (eg: sys-default), that can't be activated when other default runtime (eg: js-default) or similar are activated (compiler error)
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We already have a feature called sys-default. What would happen if sys is enabled but not sys-default?
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Basically, we should not have default for RuntimeEngine if there's no default defined
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If we don't want to have that because is a breaking change, then I'd have what you have now as a fallback, not as the main path
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I'll add the js-default, jsc-default, v8-default, wamr-default and wasmi-default features. The Engine::default() function will be just as it is in this PR, but before the feature = "sys" cfgs I'll add a
#[cfg(feature = "sys-default")] for each runtime. Sounds good? Is this what you meant?
What's missing:
mangle-symbolsfeature wasmi-labs/wasmi#1312, Addprefix-symbolsfeature wasmi-labs/wasmi#1315)