Heejin Ahn d2d469eb79
[WebAssembly] Make llvm.wasm.throw invokable (#128104)
`llvm.wasm.throw` intrinsic can throw but it was not invokable. Not sure
what the rationale was when it was first written that way, but I think
at least in Emscripten's C++ exception support with the Wasm port of
libunwind, `__builtin_wasm_throw`, which is lowered down to
`llvm.wasm.rethrow`, is used only within `_Unwind_RaiseException`, which
is an one-liner and thus does not need an `invoke`:
720e97f76d/system/lib/libunwind/src/Unwind-wasm.c (L69)
(`_Unwind_RaiseException` is called by `__cxa_throw`, which is generated
by the `throw` C++ keyword)

But this does not address other direct uses of the builtin in C++, whose
use I'm not sure about but is not prohibited. Also other language
frontends may need to use the builtin in different functions, which has
`try`-`catch`es or destructors.

This makes `llvm.wasm.throw` invokable in the backend. To do that, this
adds a custom lowering routine to `SelectionDAGBuilder::visitInvoke`,
like we did for `llvm.wasm.rethrow`.

This does not generate `invoke`s for `__builtin_wasm_throw` yet, which
will be done by a follow-up PR.

Addresses #124710.
2025-02-25 09:53:01 -08:00
..
2022-08-24 22:41:38 +00:00
2023-11-01 10:46:31 +01:00

This directory contains testcases that the verifier is supposed to detect as
malformed LLVM code.  Testcases for situations that the verifier incorrectly
identifies as malformed should go in the test/Assembler directory.