llvm-project

15715f40 - [WebAssembly,llvm] Add llvm.wasm.ref.test.func intrinsic (#147486)

[WebAssembly,llvm] Add llvm.wasm.ref.test.func intrinsic (#147486) This adds an llvm intrinsic for WebAssembly to test the type of a function. It is intended for adding a future clang builtin ` __builtin_wasm_test_function_pointer_signature` so we can test whether calling a function pointer will fail with function signature mismatch. Since the type of a function pointer is just `ptr` we can't figure out the expected type from that. The way I figured out to encode the type was by passing 0's of the appropriate type to the intrinsic. The first argument gives the expected type of the return type and the later values give the expected type of the arguments. So ```llvm @llvm.wasm.ref.test.func(ptr %func, float 0.000000e+00, double 0.000000e+00, i32 0) ``` tests if `%func` is of type `(double, i32) -> (i32)`. It will lower to: ```wat local.get $func table.get $__indirect_function_table ref.test (double, i32) -> (i32) ``` To indicate the function should be void, I somewhat arbitrarily picked `token poison`, so the following tests for `(i32) -> ()`: ```llvm @llvm.wasm.ref.test.func(ptr %func, token poison, i32 0) ``` To lower this intrinsic, we need some place to put the type information. With `encodeFunctionSignature()` we encode the signature information into an `APInt`. We decode it in `lowerEncodedFunctionSignature` in `WebAssemblyMCInstLower.cpp`.