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, 31 insertions, 0 deletions

diff --git a/test/passes/legalize-js-interface_all-features.wast b/test/passes/legalize-js-interface_all-features.wast
new file mode 100644
index 000000000..4697a8f18
--- /dev/null
+++ b/test/passes/legalize-js-interface_all-features.wast
@@ -0,0 +1,31 @@
+(module
+  (import "env" "imported" (func $imported (result i64)))
+  (import "env" "other" (func $other (param i32) (param i64) (param i64)))
+  (import "env" "ref-func-arg" (func $ref-func-arg (result i64)))
+  (export "func" (func $func))
+  (export "ref-func-test" (func $ref-func-test))
+  (export "imported" (func $imported))
+  (export "imported_again" (func $imported))
+  (export "other" (func $other))
+  (func $func (result i64)
+    (drop (call $imported))
+    (call $other
+      (i32.const 0)
+      (i64.const 0)
+      (i64.const 0)
+    )
+    (unreachable)
+  )
+
+  ;; If an import is used in ref.func, even if it is legalized to another
+  ;; import, the original import should not be removed.
+  (func $ref-func-test
+    (drop
+      (call $ref-func-arg)
+    )
+    (drop
+      (ref.func $ref-func-arg)
+    )
+  )
+)
+(module)