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, 12 insertions, 3 deletions

diff --git a/src/ir/ExpressionManipulator.cpp b/src/ir/ExpressionManipulator.cpp
index fbee9f9c1..acea09bad 100644
--- a/src/ir/ExpressionManipulator.cpp
+++ b/src/ir/ExpressionManipulator.cpp
@@ -58,7 +58,7 @@ flexibleCopy(Expression* original, Module& wasm, CustomCopier custom) {
                             curr->type);
     }
     Expression* visitLoop(Loop* curr) {
-      return builder.makeLoop(curr->name, copy(curr->body));
+      return builder.makeLoop(curr->name, copy(curr->body), curr->type);
     }
     Expression* visitBreak(Break* curr) {
       return builder.makeBreak(
@@ -208,8 +208,10 @@ flexibleCopy(Expression* original, Module& wasm, CustomCopier custom) {
       return builder.makeBinary(curr->op, copy(curr->left), copy(curr->right));
     }
     Expression* visitSelect(Select* curr) {
-      return builder.makeSelect(
-        copy(curr->condition), copy(curr->ifTrue), copy(curr->ifFalse));
+      return builder.makeSelect(copy(curr->condition),
+                                copy(curr->ifTrue),
+                                copy(curr->ifFalse),
+                                curr->type);
     }
     Expression* visitDrop(Drop* curr) {
       return builder.makeDrop(copy(curr->value));
@@ -226,6 +228,13 @@ flexibleCopy(Expression* original, Module& wasm, CustomCopier custom) {
         builder.makeHost(curr->op, curr->nameOperand, std::move(operands));
       return ret;
     }
+    Expression* visitRefNull(RefNull* curr) { return builder.makeRefNull(); }
+    Expression* visitRefIsNull(RefIsNull* curr) {
+      return builder.makeRefIsNull(copy(curr->value));
+    }
+    Expression* visitRefFunc(RefFunc* curr) {
+      return builder.makeRefFunc(curr->func);
+    }
     Expression* visitTry(Try* curr) {
       return builder.makeTry(
         copy(curr->body), copy(curr->catchBody), curr->type);