[wasm] Implement importing of WebAssembly.Memory.

test/mjsunit/wasm/import-memory.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
+
+load("test/mjsunit/wasm/wasm-constants.js");
+load("test/mjsunit/wasm/wasm-module-builder.js");
+
+(function TestOne() {
+  print("TestOne");
+  let memory = new WebAssembly.Memory({initial: 1});
+  assertEquals(65536, memory.buffer.byteLength);

[ahaas, 2016/10/07 08:23:36]

Can we put 65536 into a constant, maybe in wasm-constants.js?

[titzer, 2016/10/07 08:50:52]

Done.

+  let i32 = new Int32Array(memory.buffer);
+  let builder = new WasmModuleBuilder();
+  builder.addImportedMemory("mine");
+  builder.addFunction("main", kSig_i_v)
+    .addBody([
+      kExprI32Const, 0,
+      kExprI32LoadMem, 0, 0])
+    .exportAs("main");
+
+  let main = builder.instantiate({mine: memory}).exports.main;
+  assertEquals(0, main());
+
+  i32[0] = 993377;
+
+  assertEquals(993377, main());
+})();
+
+(function TestIdentity() {
+  print("TestIdentity");
+  let memory = new WebAssembly.Memory({initial: 1});
+  let i32 = new Int32Array(memory.buffer);
+  let builder = new WasmModuleBuilder();
+  builder.addImportedMemory("garg");
+  builder.exportMemoryAs("daggle");
+
+  let instance = builder.instantiate({garg: memory});
+  assertSame(memory, instance.exports.daggle);
+})();
+
+
+(function TestImportExport() {
+  print("TestImportExport");
+  var i1;
+  {
+    let builder = new WasmModuleBuilder();
+    builder.addMemory(1, 1, false);
+    builder.exportMemoryAs("exported_mem");
+    builder.addFunction("foo", kSig_i_i)
+      .addBody([
+        kExprGetLocal, 0,
+        kExprI32LoadMem, 0, 0])
+      .exportAs("foo");
+    i1 = builder.instantiate();
+  }
+
+  var i2;
+  {
+    let builder = new WasmModuleBuilder();
+    builder.addMemory(1, 1, false);
+    builder.addImportedMemory("imported_mem");
+    builder.addFunction("bar", kSig_i_i)
+      .addBody([
+        kExprGetLocal, 0,
+        kExprI32LoadMem, 0, 0])
+      .exportAs("bar");
+    i2 = builder.instantiate({imported_mem: i1.exports.exported_mem});
+  }
+
+  let i32 = new Int32Array(i1.exports.exported_mem.buffer);
+
+  for (var i = 0; i < 1e11; i = i * 3 + 5) {
+    for (var j = 0; j < 10; j++) {
+      var val = i + 99077 + j;
+      i32[j] = val;
+      assertEquals(val | 0, i1.exports.foo(j * 4));
+      assertEquals(val | 0, i2.exports.bar(j * 4));
+    }
+  }
+})();