Fix silent failure of WebAssembly.instantiate() (#2548)

By making WASM compilation synchronous. We'll have to do more work to
make it properly async.

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/wasm_async.js b/tests/wasm_async.js
new file mode 100644
index 000000000..7b521caee
--- /dev/null
+++ b/tests/wasm_async.js
@@ -0,0 +1,27 @@
+// The following blob can be created by taking the following s-expr and pass
+// it through wat2wasm.
+//    (module
+//      (func $add (param $a i32) (param $b i32) (result i32)
+//        local.get $a
+//        local.get $b
+//        i32.add)
+//      (export "add" (func $add))
+//    )
+// prettier-ignore
+const bytes = new Uint8Array([
+  0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00, 0x01, 0x07, 0x01, 0x60,
+  0x02, 0x7f, 0x7f, 0x01, 0x7f, 0x03, 0x02, 0x01, 0x00, 0x07, 0x07, 0x01,
+  0x03, 0x61, 0x64, 0x64, 0x00, 0x00, 0x0a, 0x09, 0x01, 0x07, 0x00, 0x20,
+  0x00, 0x20, 0x01, 0x6a, 0x0b
+]);
+
+async function main() {
+  let wasm = await WebAssembly.instantiate(bytes);
+  let result = wasm.instance.exports.add(1, 3);
+  console.log("1 + 3 =", result);
+  if (result != 4) {
+    throw Error("bad");
+  }
+}
+
+main();