Add support for reference types proposal (#2451)

This adds support for the reference type proposal. This includes support
for all reference types (`anyref`, `funcref`(=`anyfunc`), and `nullref`)
and four new instructions: `ref.null`, `ref.is_null`, `ref.func`, and
new typed `select`. This also adds subtype relationship support between
reference types.

This does not include table instructions yet. This also does not include
wasm2js support.

Fixes #2444 and fixes #2447.

1 files changed, 19 insertions, 0 deletions

diff --git a/test/exception-handling.wast.fromBinary b/test/exception-handling.wast.fromBinary
index f83ad5d48..369b17dd9 100644
--- a/test/exception-handling.wast.fromBinary
+++ b/test/exception-handling.wast.fromBinary
@@ -66,5 +66,24 @@
    )
   )
  )
+ (func $subtype_test (; 4 ;)
+  (try
+   (nop)
+   (catch
+    (drop
+     (exnref.pop)
+    )
+    (drop
+     (block $label$3 (result i32)
+      (rethrow
+       (br_on_exn $label$3 $event$0
+        (ref.null)
+       )
+      )
+     )
+    )
+   )
+  )
+ )
 )