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, 13 insertions, 3 deletions

diff --git a/src/ir/manipulation.h b/src/ir/manipulation.h
index ec137d372..49ed7e11e 100644
--- a/src/ir/manipulation.h
+++ b/src/ir/manipulation.h
@@ -33,14 +33,24 @@ inline OutputType* convert(InputType* input) {
   return output;
 }
 
-// Convenience method for nop, which is a common conversion
+// Convenience methods for certain instructions, which are common conversions
 template<typename InputType> inline Nop* nop(InputType* target) {
-  return convert<InputType, Nop>(target);
+  auto* ret = convert<InputType, Nop>(target);
+  ret->finalize();
+  return ret;
+}
+
+template<typename InputType> inline RefNull* refNull(InputType* target) {
+  auto* ret = convert<InputType, RefNull>(target);
+  ret->finalize();
+  return ret;
 }
 
 template<typename InputType>
 inline Unreachable* unreachable(InputType* target) {
-  return convert<InputType, Unreachable>(target);
+  auto* ret = convert<InputType, Unreachable>(target);
+  ret->finalize();
+  return ret;
 }
 
 // Convert a node that allocates