[GC] ref.as_* (#3520)

These are similar to is, but instead of returning an i32 answer, they trap on
an invalid value, and return it otherwise.

These could in theory be in a single RefDoThing, with opcodes for both As
and Is, but as the return values are different, that would be a little odd, and
the name would be less clear.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/wasm.h b/src/wasm.h
index 949ec3b72..094233b5c 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -549,6 +549,12 @@ enum RefIsOp {
   RefIsI31,
 };
 
+enum RefAsOp {
+  RefAsFunc,
+  RefAsData,
+  RefAsI31,
+};
+
 //
 // Expressions
 //
@@ -639,6 +645,7 @@ public:
     ArrayGetId,
     ArraySetId,
     ArrayLenId,
+    RefAsId,
     NumExpressionIds
   };
   Id _id;
@@ -1492,6 +1499,17 @@ public:
   void finalize();
 };
 
+class RefAs : public SpecificExpression<Expression::RefAsId> {
+public:
+  RefAs(MixedArena& allocator) {}
+
+  RefAsOp op;
+
+  Expression* value;
+
+  void finalize();
+};
+
 // Globals
 
 struct Importable {