Fix issues with Types and Features (#2773)

 1. Only emit exnref as part of a subtype if exception-handling is
 enabled in the fuzzer.
 2. Correctly report that funcref and nullref require reference-types
 to be enabled.
 3. Re-enable multivalue as a normal feature in the fuzzer.

Possibly fixes #2770.

2 files changed, 7 insertions, 3 deletions

diff --git a/src/tools/fuzzing.h b/src/tools/fuzzing.h
index 91a808d32..fb83882c2 100644
--- a/src/tools/fuzzing.h
+++ b/src/tools/fuzzing.h
@@ -327,8 +327,10 @@ private:
     options.push_back(type); // includes itself
     switch (type.getSingle()) {
       case Type::anyref:
+        if (wasm.features.hasExceptionHandling()) {
+          options.push_back(Type::exnref);
+        }
         options.push_back(Type::funcref);
-        options.push_back(Type::exnref);
         // falls through
       case Type::funcref:
       case Type::exnref:
diff --git a/src/wasm/wasm-type.cpp b/src/wasm/wasm-type.cpp
index d1cdf6a81..7d51cc10e 100644
--- a/src/wasm/wasm-type.cpp
+++ b/src/wasm/wasm-type.cpp
@@ -199,14 +199,16 @@ Type Type::reinterpret() const {
 }
 
 FeatureSet Type::getFeatures() const {
-  auto getSingleFeatures = [](Type t) {
+  auto getSingleFeatures = [](Type t) -> FeatureSet {
     switch (t.getSingle()) {
       case Type::v128:
         return FeatureSet::SIMD;
+      case Type::funcref:
       case Type::anyref:
+      case Type::nullref:
         return FeatureSet::ReferenceTypes;
       case Type::exnref:
-        return FeatureSet::ExceptionHandling;
+        return FeatureSet::ReferenceTypes | FeatureSet::ExceptionHandling;
       default:
         return FeatureSet::MVP;
     }