Add TagType support for WebAssembly exception-handling proposal

[bacek]

• Add WASM_EXTERN_TAG to wasm_externkind_enum
• Add WASM_DECLARE_TYPE(tagtype) with constructor and functype accessor
• Add cast functions: wasm_tagtype_as_externtype* and wasm_externtype_as_tagtype*
• Add TAG to ExternKind enum in C++ API
• Add TagType class extending ExternType with make(own<FuncType>&&) and functype() accessor
• Add tag() accessors on ExternType

Tags are described by an associated function type whose parameters are
the exception payload types (per the WebAssembly exception-handling proposal).

[rossberg]

Thanks, this is great! But it seems to need a couple of adjustments to the V8 wrapper as well, in order to unbreak CI - mostly adding a bunch of straightforward new switch cases for tag types (see the CI failures).

[bacek]

Thanks, this is great! But it seems to need a couple of adjustments to the V8 wrapper as well, in order to unbreak CI - mostly adding a bunch of straightforward new switch cases for tag types (see the CI failures).

Updated. I didn't actually implement Tag in v8 wrapper. Can try to do it in a separate PR.

[bacek]

https://github.com/WebAssembly/wasm-c-api/actions/runs/23210241938/job/67461420459?pr=197#step:6:211

mkdir -p out/example
clang++ -c -std=c++17 -DWASM_API_DEBUG   -DV8_COMPRESS_POINTERS -DV8_ENABLE_SANDBOX -Wall -Werror -ggdb -O -fsanitize=address -I. -Iv8/v8/include -I./include example/finalize.cc -o out/example/finalize-cc.o
clang++ -std=c++17 -DWASM_API_DEBUG   -DV8_COMPRESS_POINTERS -DV8_ENABLE_SANDBOX -Wall -Werror -ggdb -O -fsanitize=address -fsanitize-memory-track-origins -fsanitize-memory-use-after-dtor out/example/finalize-cc.o -o out/example/finalize-cc \
	out/./wasm-bin.o out/./wasm-v8.o \
	 \
	v8/v8/out.gn/x64.release/obj/libv8_monolith.a \
	 \
	-ldl -pthread
../spec/interpreter/wasm   -d example/finalize.wat -o example/finalize.wasm
make: ../spec/interpreter/wasm: No such file or directory

Is it just timed out building v8? All checks are passing locally for me.

[rossberg]

Good question, I triggered a rerun.

[bacek]

Good question, I triggered a rerun.

Yep. It helped.

[bacek]

Good question, I triggered a rerun.

Tests passed. Can it be merged?