[wasm] Block compile/instantiate of large array buffers

third_party/WebKit/LayoutTests/fast/wasm/wasm-limits-tests-common.js

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function createTestBuffers(limit) {
+  let builder = new WasmModuleBuilder();
+  let body = [];
+  var fct = builder.addFunction("f", kSig_v_v);
+
+  var l = builder.toBuffer().byteLength;
+
+  // in the bare bones buffer, the size of the function f
+  // is 0, which is encoded in 1 byte. For the 2^12 case,
+  // we need 2 bytes. Then, the function ends in kExprEnd,
+  // so we need that accounted, too.
+  var remaining = limit - l - 3;
+
+  for (var i = 0; i < remaining; ++i) body.push(kExprNop);
+  fct.addBody(body);
+
+  var small_buffer = builder.toBuffer();
+  // body is now 1 larger than before, because it has the kExpEnd at the end.
+  // replace that with kExprNop, and generate a new buffer.
+  body[body.length-1] = kExprNop;
+  fct.addBody(body);
+  var large_buffer = builder.toBuffer();
+  return {small: small_buffer, large: large_buffer};
+}