wasi: use WasmMemoryObject handle for perf (#43544)

PR-URL: #43544
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

Author: devsnek

lib/wasi.js

@@ -10,14 +10,12 @@ const {
 } = primordials;
 
 const {
-  ERR_INVALID_ARG_TYPE,
   ERR_WASI_ALREADY_STARTED
 } = require('internal/errors').codes;
 const {
   emitExperimentalWarning,
   kEmptyObject,
 } = require('internal/util');
-const { isArrayBuffer } = require('internal/util/types');
 const {
   validateArray,
   validateBoolean,
@@ -39,20 +37,6 @@ function setupInstance(self, instance) {
   validateObject(instance, 'instance');
   validateObject(instance.exports, 'instance.exports');
 
-  // WASI::_SetMemory() in src/node_wasi.cc only expects that |memory| is
-  // an object. It will try to look up the .buffer property when needed
-  // and fail with UVWASI_EINVAL when the property is missing or is not
-  // an ArrayBuffer. Long story short, we don't need much validation here
-  // but we type-check anyway because it helps catch bugs in the user's
-  // code early.
-  validateObject(instance.exports.memory, 'instance.exports.memory');
-  if (!isArrayBuffer(instance.exports.memory.buffer)) {
-    throw new ERR_INVALID_ARG_TYPE(
-      'instance.exports.memory.buffer',
-      ['WebAssembly.Memory'],
-      instance.exports.memory.buffer);
-  }
-
   self[kInstance] = instance;
   self[kSetMemory](instance.exports.memory);
 }

src/node_wasi.cc

@@ -72,9 +72,7 @@ inline void Debug(WASI* wasi, Args&&... args) {
     }                                                                         \
   } while (0)
 
-
 using v8::Array;
-using v8::ArrayBuffer;
 using v8::BackingStore;
 using v8::BigInt;
 using v8::Context;
@@ -89,7 +87,7 @@ using v8::Object;
 using v8::String;
 using v8::Uint32;
 using v8::Value;
-
+using v8::WasmMemoryObject;
 
 static MaybeLocal<Value> WASIException(Local<Context> context,
                                        int errorno,
@@ -1642,26 +1640,22 @@ void WASI::SockShutdown(const FunctionCallbackInfo<Value>& args) {
 
 void WASI::_SetMemory(const FunctionCallbackInfo<Value>& args) {
   WASI* wasi;
-  CHECK_EQ(args.Length(), 1);
-  CHECK(args[0]->IsObject());
   ASSIGN_OR_RETURN_UNWRAP(&wasi, args.This());
-  wasi->memory_.Reset(wasi->env()->isolate(), args[0].As<Object>());
+  CHECK_EQ(args.Length(), 1);
+  if (!args[0]->IsWasmMemoryObject()) {
+    return node::THROW_ERR_INVALID_ARG_TYPE(
+        wasi->env(),
+        "\"instance.exports.memory\" property must be a WebAssembly.Memory "
+        "object");
+  }
+  wasi->memory_.Reset(wasi->env()->isolate(), args[0].As<WasmMemoryObject>());
 }
 
 
 uvwasi_errno_t WASI::backingStore(char** store, size_t* byte_length) {
-  Environment* env = this->env();
-  Local<Object> memory = PersistentToLocal::Strong(this->memory_);
-  Local<Value> prop;
-
-  if (!memory->Get(env->context(), env->buffer_string()).ToLocal(&prop))
-    return UVWASI_EINVAL;
-
-  if (!prop->IsArrayBuffer())
-    return UVWASI_EINVAL;
-
-  Local<ArrayBuffer> ab = prop.As<ArrayBuffer>();
-  std::shared_ptr<BackingStore> backing_store = ab->GetBackingStore();
+  Local<WasmMemoryObject> memory = PersistentToLocal::Strong(this->memory_);
+  std::shared_ptr<BackingStore> backing_store =
+      memory->Buffer()->GetBackingStore();
   *byte_length = backing_store->ByteLength();
   *store = static_cast<char*>(backing_store->Data());
   CHECK_NOT_NULL(*store);

src/node_wasi.h

@@ -94,7 +94,7 @@ class WASI : public BaseObject,
   inline void writeUInt64(char* memory, uint64_t value, uint32_t offset);
   uvwasi_errno_t backingStore(char** store, size_t* byte_length);
   uvwasi_t uvw_;
-  v8::Global<v8::Object> memory_;
+  v8::Global<v8::WasmMemoryObject> memory_;
   uvwasi_mem_t alloc_info_;
   size_t current_uvwasi_memory_ = 0;
 };

test/wasi/test-wasi-initialize-validation.js

@@ -47,7 +47,10 @@ const bufferSource = fixtures.readSync('simple.wasm');
 
     Object.defineProperty(instance, 'exports', {
       get() {
-        return { _initialize: 5, memory: new Uint8Array() };
+        return {
+          _initialize: 5,
+          memory: new WebAssembly.Memory({ initial: 1 }),
+        };
       },
     });
     assert.throws(
@@ -70,7 +73,7 @@ const bufferSource = fixtures.readSync('simple.wasm');
         return {
           _start() {},
           _initialize() {},
-          memory: new Uint8Array(),
+          memory: new WebAssembly.Memory({ initial: 1 }),
         };
       }
     });
@@ -97,55 +100,11 @@ const bufferSource = fixtures.readSync('simple.wasm');
       () => { wasi.initialize(instance); },
       {
         code: 'ERR_INVALID_ARG_TYPE',
-        message: /"instance\.exports\.memory" property must be of type object/
+        message: /"instance\.exports\.memory" property must be a WebAssembly\.Memory object/
       }
     );
   }
 
-  {
-    // Verify that a non-ArrayBuffer memory.buffer is rejected.
-    const wasi = new WASI({});
-    const wasm = await WebAssembly.compile(bufferSource);
-    const instance = await WebAssembly.instantiate(wasm);
-
-    Object.defineProperty(instance, 'exports', {
-      get() {
-        return {
-          _initialize() {},
-          memory: {},
-        };
-      }
-    });
-    // The error message is a little white lie because any object
-    // with a .buffer property of type ArrayBuffer is accepted,
-    // but 99% of the time a WebAssembly.Memory object is used.
-    assert.throws(
-      () => { wasi.initialize(instance); },
-      {
-        code: 'ERR_INVALID_ARG_TYPE',
-        message: /"instance\.exports\.memory\.buffer" property must be an WebAssembly\.Memory/
-      }
-    );
-  }
-
-  {
-    // Verify that an argument that duck-types as a WebAssembly.Instance
-    // is accepted.
-    const wasi = new WASI({});
-    const wasm = await WebAssembly.compile(bufferSource);
-    const instance = await WebAssembly.instantiate(wasm);
-
-    Object.defineProperty(instance, 'exports', {
-      get() {
-        return {
-          _initialize() {},
-          memory: { buffer: new ArrayBuffer(0) },
-        };
-      }
-    });
-    wasi.initialize(instance);
-  }
-
   {
     // Verify that a WebAssembly.Instance from another VM context is accepted.
     const wasi = new WASI({});

test/wasi/test-wasi-start-validation.js

@@ -47,7 +47,7 @@ const bufferSource = fixtures.readSync('simple.wasm');
 
     Object.defineProperty(instance, 'exports', {
       get() {
-        return { memory: new Uint8Array() };
+        return { memory: new WebAssembly.Memory({ initial: 1 }) };
       },
     });
     assert.throws(
@@ -70,7 +70,7 @@ const bufferSource = fixtures.readSync('simple.wasm');
         return {
           _start() {},
           _initialize() {},
-          memory: new Uint8Array(),
+          memory: new WebAssembly.Memory({ initial: 1 }),
         };
       }
     });
@@ -97,55 +97,11 @@ const bufferSource = fixtures.readSync('simple.wasm');
       () => { wasi.start(instance); },
       {
         code: 'ERR_INVALID_ARG_TYPE',
-        message: /"instance\.exports\.memory" property must be of type object/
+        message: /"instance\.exports\.memory" property must be a WebAssembly\.Memory object/
       }
     );
   }
 
-  {
-    // Verify that a non-ArrayBuffer memory.buffer is rejected.
-    const wasi = new WASI({});
-    const wasm = await WebAssembly.compile(bufferSource);
-    const instance = await WebAssembly.instantiate(wasm);
-
-    Object.defineProperty(instance, 'exports', {
-      get() {
-        return {
-          _start() {},
-          memory: {},
-        };
-      }
-    });
-    // The error message is a little white lie because any object
-    // with a .buffer property of type ArrayBuffer is accepted,
-    // but 99% of the time a WebAssembly.Memory object is used.
-    assert.throws(
-      () => { wasi.start(instance); },
-      {
-        code: 'ERR_INVALID_ARG_TYPE',
-        message: /"instance\.exports\.memory\.buffer" property must be an WebAssembly\.Memory/
-      }
-    );
-  }
-
-  {
-    // Verify that an argument that duck-types as a WebAssembly.Instance
-    // is accepted.
-    const wasi = new WASI({});
-    const wasm = await WebAssembly.compile(bufferSource);
-    const instance = await WebAssembly.instantiate(wasm);
-
-    Object.defineProperty(instance, 'exports', {
-      get() {
-        return {
-          _start() {},
-          memory: { buffer: new ArrayBuffer(0) },
-        };
-      }
-    });
-    wasi.start(instance);
-  }
-
   {
     // Verify that a WebAssembly.Instance from another VM context is accepted.
     const wasi = new WASI({});