[wasm] Avoid double-serializing the wire bytes

src/runtime/runtime-test.cc

Index: src/runtime/runtime-test.cc
diff --git a/src/runtime/runtime-test.cc b/src/runtime/runtime-test.cc
index 1f6efa168fcf89dbce5f4b4e1c2274da6b88aadc..7d9e90450bf6dc69b1e4eccaf3f5bbddf1e3d846 100644
--- a/src/runtime/runtime-test.cc
+++ b/src/runtime/runtime-test.cc
@@ -754,15 +754,23 @@ RUNTIME_FUNCTION(Runtime_SerializeWasmModule) {
 // Return undefined if unsuccessful.
 RUNTIME_FUNCTION(Runtime_DeserializeWasmModule) {
   HandleScope shs(isolate);
-  DCHECK(args.length() == 1);
+  DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, buffer, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, wire_bytes, 1);
 
   Address mem_start = static_cast<Address>(buffer->backing_store());
   int mem_size = static_cast<int>(buffer->byte_length()->Number());
 
+  // DeserializeWasmModule will allocate. We assume JSArrayBuffer doesn't
+  // get relocated.
   ScriptData sc(mem_start, mem_size);
   MaybeHandle<FixedArray> maybe_compiled_module =
-      WasmCompiledModuleSerializer::DeserializeWasmModule(isolate, &sc);
+      WasmCompiledModuleSerializer::DeserializeWasmModule(
+          isolate, &sc,
+          Vector<const uint8_t>(
+              reinterpret_cast<uint8_t*>(wire_bytes->backing_store()),

[titzer, 2016/10/20 08:32:08]

This raw pointer is unsafe unless the buffer is externalized first.

[Mircea Trofin, 2016/10/20 16:06:41]

Done, and added mlippautz to double-check this is the expected use of the
Register/Unregister APIs.

+              static_cast<int>(wire_bytes->byte_length()->Number())));
+
   Handle<FixedArray> compiled_module;
   if (!maybe_compiled_module.ToHandle(&compiled_module)) {
     return isolate->heap()->undefined_value();