[wasm] WebAssembly.Memory.grow() should handle the no instance case

test/mjsunit/wasm/js-api.js

 // Copyright 2016 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.
 
 // Flags: --expose-wasm --allow-natives-syntax
 
 if ((typeof drainJobQueue) != "function") {
   drainJobQueue = () => { %RunMicrotasks() };
 }
 
@@ skipping 355 matching lines @@
 assertEq(bufferGetter.call(mem1).byteLength, kPageSize);
 
 // 'WebAssembly.Memory.prototype.grow' data property
 let memGrowDesc = Object.getOwnPropertyDescriptor(memoryProto, 'grow');
 assertEq(typeof memGrowDesc.value, "function");
 assertEq(memGrowDesc.enumerable, false);
 assertEq(memGrowDesc.configurable, true);
 
 // 'WebAssembly.Memory.prototype.grow' method
 
-if (false) { // TODO: bugs with Memory.grow
 let memGrow = memGrowDesc.value;
 assertEq(memGrow.length, 1);
-assertErrorMessage(() => memGrow.call(), TypeError, /called on incompatible undefined/);
-assertErrorMessage(() => memGrow.call({}), TypeError, /called on incompatible Object/);
-assertErrorMessage(() => memGrow.call(mem1, -1), RangeError, /bad Memory grow delta/);
-assertErrorMessage(() => memGrow.call(mem1, Math.pow(2,32)), RangeError, /bad Memory grow delta/);
+assertErrorMessage(() => memGrow.call(), TypeError,
+    /called on incompatible undefined/);
+assertErrorMessage(() => memGrow.call({}), TypeError,
+    /called on incompatible Object/);
+assertErrorMessage(() => memGrow.call(mem1, -1), RangeError,
+    /bad Memory grow delta/);
+assertErrorMessage(() => memGrow.call(mem1, Math.pow(2,32)), RangeError,
+    /bad Memory grow delta/);
 var mem = new Memory({initial:1, maximum:2});
 var buf = mem.buffer;
 assertEq(buf.byteLength, kPageSize);
 assertEq(mem.grow(0), 1);
-assertEq(buf !== mem.buffer, true);
-assertEq(buf.byteLength, 0);
+// TODO(gdeepti): assertEq(buf !== mem.buffer, true);

[bradnelson, 2017/01/18 02:35:37]

Maybe say pending spec clarification (ideally ref the filled github issue)

[gdeepti, 2017/01/18 04:43:14]

Done.

+// TODO(gdeepti): assertEq(buf.byteLength, 0);
 buf = mem.buffer;
 assertEq(buf.byteLength, kPageSize);
 assertEq(mem.grow(1), 1);
-assertEq(buf !== mem.buffer, true);
-assertEq(buf.byteLength, 0);
+// TODO(gdeepti): assertEq(buf !== mem.buffer, true);
+// TODO(gdeepti): assertEq(buf.byteLength, 0);

[gdeepti, 2017/01/18 02:17:47]

Disabled for now because for the 0 case, we do not allocate a new buffer, second
case fails with guard pages enabled. 

 buf = mem.buffer;
 assertEq(buf.byteLength, 2 * kPageSize);
 assertErrorMessage(() => mem.grow(1), Error, /failed to grow memory/);
 assertEq(buf, mem.buffer);
-}
 
 // 'WebAssembly.Table' data property
 let tableDesc = Object.getOwnPropertyDescriptor(WebAssembly, 'Table');
 assertEq(typeof tableDesc.value, "function");
 assertEq(tableDesc.writable, true);
 assertEq(tableDesc.enumerable, false);
 assertEq(tableDesc.configurable, true);
 
 // 'WebAssembly.Table' constructor function
 let Table = WebAssembly.Table;
@@ skipping 213 matching lines @@
   var result = null;
   instantiate(module_bytes, imports).then(r => result = r).catch(e => print(e));
   drainJobQueue();
   assertEq(result instanceof Instance, true);
 }
 assertInstantiateSuccess(emptyModuleBinary);
 assertInstantiateSuccess(emptyModuleBinary.buffer);
 assertInstantiateSuccess(importingModuleBinary, {"":{f:()=>{}}});
 assertInstantiateSuccess(importingModuleBinary.buffer, {"":{f:()=>{}}});
 assertInstantiateSuccess(memoryImportingModuleBinary, {"": {"my_memory": scratch_memory}});