4 files changed, 29 insertions, 17 deletions

diff --git a/src/asmjs/asm_v_wasm.cpp b/src/asmjs/asm_v_wasm.cpp
index 314c2494f..bbbaad5bc 100644
--- a/src/asmjs/asm_v_wasm.cpp
+++ b/src/asmjs/asm_v_wasm.cpp
@@ -21,6 +21,10 @@
 namespace wasm {
 
 JsType wasmToJsType(Type type) {
+  if (type.isRef()) {
+    return JS_REF;
+  }
+
   TODO_SINGLE_COMPOUND(type);
   switch (type.getBasic()) {
     case Type::i32:
diff --git a/src/emscripten-optimizer/optimizer-shared.cpp b/src/emscripten-optimizer/optimizer-shared.cpp
index 8208f6f47..773c5d9fc 100644
--- a/src/emscripten-optimizer/optimizer-shared.cpp
+++ b/src/emscripten-optimizer/optimizer-shared.cpp
@@ -104,6 +104,11 @@ Ref makeJsCoercedZero(JsType type) {
   abort();
 }
 
+bool needsJsCoercion(JsType type) {
+  // References need no coercion, but everything else does.
+  return type != JS_REF;
+}
+
 Ref makeJsCoercion(Ref node, JsType type) {
   switch (type) {
     case JS_INT:
@@ -122,10 +127,11 @@ Ref makeJsCoercion(Ref node, JsType type) {
       return ValueBuilder::makeCall(SIMD_INT16X8_CHECK, node);
     case JS_INT32X4:
       return ValueBuilder::makeCall(SIMD_INT32X4_CHECK, node);
+    case JS_REF:
     case JS_NONE:
     default:
-      // non-validating code, emit nothing XXX this is dangerous, we should only
-      // allow this when we know we are not validating
+      // No coercion is needed.
+      // TODO see if JS_NONE is actually used here.
       return node;
   }
 }
diff --git a/src/emscripten-optimizer/optimizer.h b/src/emscripten-optimizer/optimizer.h
index a27fe25eb..6347c194c 100644
--- a/src/emscripten-optimizer/optimizer.h
+++ b/src/emscripten-optimizer/optimizer.h
@@ -39,6 +39,7 @@ enum JsType {
   JS_INT16X8,
   JS_INT32X4,
   JS_INT64,
+  JS_REF,
   JS_NONE // number of types
 };
 
@@ -51,6 +52,7 @@ enum JsSign {
 };
 
 cashew::Ref makeJsCoercedZero(JsType type);
+bool needsJsCoercion(JsType type);
 cashew::Ref makeJsCoercion(cashew::Ref node, JsType type);
 cashew::Ref makeSigning(cashew::Ref node, JsSign sign);
 
diff --git a/src/wasm2js.h b/src/wasm2js.h
index 7540bd71a..2084c0453 100644
--- a/src/wasm2js.h
+++ b/src/wasm2js.h
@@ -921,11 +921,13 @@ Ref Wasm2JSBuilder::processFunction(Module* m,
     IString name = fromName(func->getLocalNameOrGeneric(i), NameScope::Local);
     ValueBuilder::appendArgumentToFunction(ret, name);
     if (needCoercions) {
-      ret[3]->push_back(ValueBuilder::makeStatement(ValueBuilder::makeBinary(
-        ValueBuilder::makeName(name),
-        SET,
-        makeJsCoercion(ValueBuilder::makeName(name),
-                       wasmToJsType(func->getLocalType(i))))));
+      auto jsType = wasmToJsType(func->getLocalType(i));
+      if (needsJsCoercion(jsType)) {
+        ret[3]->push_back(ValueBuilder::makeStatement(ValueBuilder::makeBinary(
+          ValueBuilder::makeName(name),
+          SET,
+          makeJsCoercion(ValueBuilder::makeName(name), jsType))));
+      }
     }
   }
   Ref theVar = ValueBuilder::makeVar();
@@ -2219,21 +2221,19 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
                                     visit(curr->value, EXPRESSION_RESULT),
                                     visit(curr->size, EXPRESSION_RESULT));
     }
-    Ref visitRefNull(RefNull* curr) {
-      unimplemented(curr);
-      WASM_UNREACHABLE("unimp");
-    }
+    Ref visitRefNull(RefNull* curr) { return ValueBuilder::makeName("null"); }
     Ref visitRefIsNull(RefIsNull* curr) {
-      unimplemented(curr);
-      WASM_UNREACHABLE("unimp");
+      return ValueBuilder::makeBinary(visit(curr->value, EXPRESSION_RESULT),
+                                      EQ,
+                                      ValueBuilder::makeName("null"));
     }
     Ref visitRefFunc(RefFunc* curr) {
-      unimplemented(curr);
-      WASM_UNREACHABLE("unimp");
+      return ValueBuilder::makeName(fromName(curr->func, NameScope::Top));
     }
     Ref visitRefEq(RefEq* curr) {
-      unimplemented(curr);
-      WASM_UNREACHABLE("unimp");
+      return ValueBuilder::makeBinary(visit(curr->left, EXPRESSION_RESULT),
+                                      EQ,
+                                      visit(curr->right, EXPRESSION_RESULT));
     }
     Ref visitTableGet(TableGet* curr) {
       unimplemented(curr);