Add support for the reference types proposal (#938)

* Add support for the reference types proposal

This commit adds support for the reference types proposal to wabt.
Namely it adds new opcodes like `table.{get,set,grow}` as well as adds a
new `anyref` type. These are plumbed throughout for various operations
in relatively simple fashions, no support was added for a subtyping
relationship between `anyref` and `anyfunc` just yet.

This also raises the restriction that multiple tables are disallowed,
allowing multiple tables to exist when `--enable-reference-types` is
passed.

* Allow nonzero table indices in `call_indirect`

Plumb support throughout for the `call_indirect` instruction (and
`return_call_indirect`) to work with multi-table modules according to
the reference types proposal.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/common.h b/src/common.h
index 4a2311d4..49c1ce60 100644
--- a/src/common.h
+++ b/src/common.h
@@ -205,6 +205,7 @@ enum class Type : int32_t {
   F64 = -0x04,        // 0x7c
   V128 = -0x05,       // 0x7b
   Anyfunc = -0x10,    // 0x70
+  Anyref = -0x11,     // 0x6f
   ExceptRef = -0x18,  // 0x68
   Func = -0x20,       // 0x60
   Void = -0x40,       // 0x40
@@ -359,6 +360,8 @@ static WABT_INLINE const char* GetTypeName(Type type) {
       return "void";
     case Type::Any:
       return "any";
+    case Type::Anyref:
+      return "anyref";
     default:
       return "<type index>";
   }