[wasm] Small memory size crashes.

test/mjsunit/wasm/module-memory.js

 // Copyright 2015 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 --expose-gc --stress-compaction
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 var kMemSize = 65536;
@@ skipping 24 matching lines @@
       /*  */ kExprEnd,                     // --
       /**/ kExprI8Const, 0                 // --
     ])
     .exportFunc();
   var module = builder.instantiate(null, memory);
   assertTrue(module.exports.memory instanceof WebAssembly.Memory);
   if (memory != null) assertEquals(memory, module.exports.memory.buffer);
   return module;
 }
 
+
+function testSmallMemory() {
+  var buffer = new ArrayBuffer(1);

[gdeepti, 2016/10/07 02:50:52]

Following up from offline discussions, this test should not pass because the 
 - Memory is not aligned to page size. 
 - Imported memory should be in the form of WebAssembly.Memory object

I will follow up to add checks in Instantiate/GrowMemory/MemorySize methods for
the memory to be aligned to page size. 

+  var module = genModule(buffer);
+  var main = module.exports.main;
+  assertEquals(1, buffer.byteLength);
+  assertEquals(0, main(0));
+}
+
+testSmallMemory();
+
+
 function testPokeMemory() {
   var module = genModule(null);
   var buffer = module.exports.memory.buffer;
   var main = module.exports.main;
   assertEquals(kMemSize, buffer.byteLength);
 
   var array = new Int8Array(buffer);
   assertEquals(kMemSize, array.length);
 
   for (var i = 0; i < kMemSize; i++) {
@@ skipping 103 matching lines @@
   }
 
 
   for (offset = 65534; offset < 66536; offset++) {
     assertTraps(kTrapMemOutOfBounds, read);
     assertTraps(kTrapMemOutOfBounds, write);
   }
 }
 
 testOOBThrows();