[Stack Switching] Handle a null in ContNew (#7838)

Author: kripken

src/wasm-interpreter.h

@@ -4824,7 +4824,11 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
       return funcFlow;
     }
     // Create a new continuation for the target function.
-    Name funcName = funcFlow.getSingleValue().getFunc();
+    auto funcValue = funcFlow.getSingleValue();
+    if (funcValue.isNull()) {
+      trap("null ref");
+    }
+    auto funcName = funcValue.getFunc();
     auto* func = self()->getModule()->getFunction(funcName);
     return Literal(std::make_shared<ContData>(
       self()->makeFuncData(func->name, func->type), curr->type.getHeapType()));

test/spec/cont.wast

@@ -117,11 +117,17 @@
     (call $nl4 (cont.new $k1 (ref.func $r1)))
   )
 
-  (func (export "null")
+  (func (export "null-resume")
     (resume $k1
       (ref.null $k1)
     )
   )
+
+  (func (export "null-new") (result (ref null $k1))
+    (cont.new $k1
+      (ref.null $f1)
+    )
+  )
 )
 
 (assert_suspension (invoke "unhandled-1") "unhandled")
@@ -138,7 +144,8 @@
 (assert_trap (invoke "non-linear-3") "continuation already consumed")
 (assert_trap (invoke "non-linear-4") "continuation already consumed")
 
-(assert_trap (invoke "null") "null continuation reference")
+(assert_trap (invoke "null-resume") "null continuation reference")
+(assert_trap (invoke "null-new") "null function reference")
 
 (assert_invalid
   (module