[GC] RefIsNull => RefIs. (#3516)

This internal refactoring prepares us for ref.is_func/data/i31, by renaming
the node and adding an "op" field. For now that field must always be "Null"
which means it is a ref.is_null.

This adjusts the C API to match the new IR shape. The high-level JS API
is unchanged.

1 files changed, 8 insertions, 3 deletions

diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index 44173d395..1d07af46a 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -1306,15 +1306,20 @@ public:
     NOTE_ENTER("RefNull");
     return Literal::makeNull(curr->type);
   }
-  Flow visitRefIsNull(RefIsNull* curr) {
-    NOTE_ENTER("RefIsNull");
+  Flow visitRefIs(RefIs* curr) {
+    NOTE_ENTER("RefIs");
     Flow flow = visit(curr->value);
     if (flow.breaking()) {
       return flow;
     }
     const auto& value = flow.getSingleValue();
     NOTE_EVAL1(value);
-    return Literal(value.isNull());
+    switch (curr->op) {
+      case RefIsNull:
+        return Literal(value.isNull());
+      default:
+        WASM_UNREACHABLE("unimplemented ref.is_*");
+    }
   }
   Flow visitRefFunc(RefFunc* curr) {
     NOTE_ENTER("RefFunc");