I fixed support for varargs functions
(previously it didn't crash but the codegen was incorrect).
I added tests for structs and unions which already work. With the
multivalue abi they crash in the backend, so I added a sema check that
rejects structs and unions for that abi.
It will also crash in the backend if passed an int128 or float128 type.
Tests if the runtime type of the function pointer matches the static
type. If this returns false, calling the function pointer will trap.
Uses `@llvm.wasm.ref.test.func` added in #147486.
Also adds a "gc" wasm feature to gate the use of the ref.test
instruction.
I also fixed __builtin_wasm_ref_null_extern() to generate a diagnostic
when it gets an argument. It seems like `SemaRef.checkArgCount()` has a
bug that makes it unable to check for 0 args.
clang/lib/CodeGen/CGBuiltin.cpp is over 1MB long (>23k LoC), and can
take minutes to recompile (depending on compiler and host system) when
modified, and 5 seconds for clangd to update for every edit. Splitting
this file was discussed in this thread:
https://discourse.llvm.org/t/splitting-clang-s-cgbuiltin-cpp-over-23k-lines-long-takes-1min-to-compile/
and the idea has received a number of +1 votes, hence this change.
