Add anyref feature and type (#3109)

Adds `anyref` type, which is enabled by a new feature `--enable-anyref`. This type is primarily used for testing that passes correctly handle subtype relationships so that the codebase will continue to be prepared for future subtyping. Since `--enable-anyref` is meaningless without also using `--enable-reference-types`, this PR also makes it a validation error to pass only the former (and similarly makes it a validation error to enable exception handling without enabling reference types).

1 files changed, 3 insertions, 0 deletions

diff --git a/src/asmjs/asm_v_wasm.cpp b/src/asmjs/asm_v_wasm.cpp
index ddcb27d3d..8d2894f13 100644
--- a/src/asmjs/asm_v_wasm.cpp
+++ b/src/asmjs/asm_v_wasm.cpp
@@ -57,6 +57,7 @@ AsmType wasmToAsmType(Type type) {
     case Type::funcref:
     case Type::externref:
     case Type::exnref:
+    case Type::anyref:
       assert(false && "reference types are not supported by asm2wasm");
     case Type::none:
       return ASM_NONE;
@@ -85,6 +86,8 @@ char getSig(Type type) {
       return 'X';
     case Type::exnref:
       return 'E';
+    case Type::anyref:
+      return 'A';
     case Type::none:
       return 'v';
     case Type::unreachable: