1 files changed, 29 insertions, 0 deletions
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index a29867e55..1eb31157d 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -1342,6 +1342,35 @@ public:
     }
     return makeBrOn(op, name, ref);
   }
+
+  template<typename T>
+  Expression* validateAndMakeCallRef(Expression* target,
+                                     const T& args,
+                                     bool isReturn = false) {
+    if (target->type != Type::unreachable && !target->type.isRef()) {
+      throw ParseException("Non-reference type for a call_ref", line, col);
+    }
+    // TODO: This won't be necessary once type annotations are mandatory on
+    // call_ref.
+    if (target->type == Type::unreachable ||
+        target->type.getHeapType() == HeapType::nofunc) {
+      // An unreachable target is not supported. Similiar to br_on_cast, just
+      // emit an unreachable sequence, since we don't have enough information
+      // to create a full call_ref.
+      std::vector<Expression*> children;
+      for (auto* arg : args) {
+        children.push_back(makeDrop(arg));
+      }
+      children.push_back(makeDrop(target));
+      children.push_back(makeUnreachable());
+      return makeBlock(children, Type::unreachable);
+    }
+    auto heapType = target->type.getHeapType();
+    if (!heapType.isSignature()) {
+      throw ParseException("Invalid reference type for a call_ref", line, col);
+    }
+    return makeCallRef(target, args, heapType.getSignature().results, isReturn);
+  }
 };
 
 } // namespace wasm