[wasm] Avoid double-serializing the wire bytes

src/runtime/runtime-test.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <memory>
 
 #include "src/arguments.h"
 #include "src/compiler-dispatcher/optimizing-compile-dispatcher.h"
@@ skipping 736 matching lines @@
   Handle<JSArrayBuffer> ret = isolate->factory()->NewJSArrayBuffer();
   JSArrayBuffer::Setup(ret, isolate, false, buff, data->length());
   memcpy(buff, data->data(), data->length());
   return *ret;
 }
 
 // Take an array buffer and attempt to reconstruct a compiled wasm module.
 // 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();
   }
   return *wasm::CreateWasmModuleObject(
       isolate, Handle<wasm::WasmCompiledModule>::cast(compiled_module),
       wasm::kWasmOrigin);
 }
 
 RUNTIME_FUNCTION(Runtime_ValidateWasmInstancesChain) {
@@ skipping 17 matching lines @@
 RUNTIME_FUNCTION(Runtime_ValidateWasmOrphanedInstance) {
   HandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, instance_obj, 0);
   wasm::testing::ValidateOrphanedInstance(isolate, instance_obj);
   return isolate->heap()->ToBoolean(true);
 }
 
 }  // namespace internal
 }  // namespace v8