Replace `RefIs` with `RefIsNull` (#5401)

* Replace `RefIs` with `RefIsNull`

The other `ref.is*` instructions are deprecated and expressible in terms of
`ref.test`. Update binary and text parsing to parse those instructions as
`RefTest` expressions. Also update the printing and emitting of `RefTest`
expressions to emit the legacy instructions for now to minimize test changes and
make this a mostly non-functional change. Since `ref.is_null` is the only
`RefIs` instruction left, remove the `RefIsOp` field and rename the expression
class to `RefIsNull`.

The few test changes are due to the fact that `ref.is*` instructions are now
subject to `ref.test` validation, and in particular it is no longer valid to
perform a `ref.is_func` on a value outside of the `func` type hierarchy.

1 files changed, 3 insertions, 14 deletions

diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index 181114c92..104f06585 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -1336,26 +1336,15 @@ public:
     NOTE_ENTER("RefNull");
     return Literal::makeNull(curr->type.getHeapType());
   }
-  Flow visitRefIs(RefIs* curr) {
-    NOTE_ENTER("RefIs");
+  Flow visitRefIsNull(RefIsNull* curr) {
+    NOTE_ENTER("RefIsNull");
     Flow flow = visit(curr->value);
     if (flow.breaking()) {
       return flow;
     }
     const auto& value = flow.getSingleValue();
     NOTE_EVAL1(value);
-    switch (curr->op) {
-      case RefIsNull:
-        return Literal(value.isNull());
-      case RefIsFunc:
-        return Literal(value.type.isFunction());
-      case RefIsData:
-        return Literal(value.isData());
-      case RefIsI31:
-        return Literal(value.type.getHeapType() == HeapType::i31);
-      default:
-        WASM_UNREACHABLE("unimplemented ref.is_*");
-    }
+    return Literal(int32_t(value.isNull()));
   }
   Flow visitRefFunc(RefFunc* curr) {
     NOTE_ENTER("RefFunc");