Further refactor TrampolineCompiler for the wasm ABI
#11939
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This is a follow-up to bytecodealliance#11932 where the `TrampolineCompiler` type is further specialized to just working with the wasm ABI instead of trying to multiplex two ABIs now that the array ABI is handled by calling the wasm ABI. This involved purging the `self.abi` field and updating all callers as appropriate. This then performed some small refactoring to use `TrampolineCompiler` for compiler intrinsics. Unsafe intrinsics also now have the same strategy of calling the wasm ABI trampoline when compiling for the array ABI. This should ensure that all entry trampolines are going through the same function.
alexcrichton
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dicej
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alexcrichton
commented
Oct 24, 2025
crates/wasmtime/src/compile.rs
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| // Skip inlining into array-abi functions which are entry | ||
| // trampolines into wasm. ABI-wise it's required that these have a | ||
| // single `try_call` into the module and it doesn't work if multiple | ||
| // get inlined or if the `try_call` goes away. Pevent all inlining | ||
| // to guarantee the structure of entry trampolines. | ||
| ( | ||
| FuncKey::ArrayToWasmTrampoline(..) | ||
| | FuncKey::ComponentTrampoline(Abi::Array, _) | ||
| | FuncKey::UnsafeIntrinsic(Abi::Array, _), | ||
| _, | ||
| ) => { | ||
| log::trace!(" --> not inlining: not inlining into array-abi caller"); | ||
| return false; | ||
| } |
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cc @fitzgen on this. One reason is that cranelift inlining doesn't support get_exception_handler_address but even if it did we couldn't properly inline in entry trampolines because we wouldn't have the right handler recorded at all call points. To handle that I disabled inlining into these callers no matter what.
My thinking is that these aren't perf-sensitive and if they are we need to figure something else out other than inlining.
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dicej
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Oct 30, 2025
dicej
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Oct 30, 2025
Co-authored-by: Joel Dice <joel.dice@fermyon.com>
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This is a follow-up to #11932 where the
TrampolineCompilertype is further specialized to just working with the wasm ABI instead of trying to multiplex two ABIs now that the array ABI is handled by calling the wasm ABI. This involved purging theself.abifield and updating all callers as appropriate.This then performed some small refactoring to use
TrampolineCompilerfor compiler intrinsics. Unsafe intrinsics also now have the same strategy of calling the wasm ABI trampoline when compiling for the array ABI. This should ensure that all entry trampolines are going through the same function.