[wasm] Add support for exporting WebAssembly.Table instances.

test/mjsunit/wasm/export-table.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 testExportedMain() {
+  print("TestExportedMain...");
   var kReturnValue = 88;
   var builder = new WasmModuleBuilder();
 
   builder.addFunction("main", kSig_i_v)
     .addBody([
       kExprI8Const,
       kReturnValue,
       kExprReturn
     ])
     .exportFunc();
 
   var module = builder.instantiate();
 
   assertEquals("object", typeof module.exports);
   assertEquals("function", typeof module.exports.main);
 
   assertEquals(kReturnValue, module.exports.main());
 })();
 
 (function testExportedTwice() {
+  print("TestExportedTwice...");
   var kReturnValue = 99;
 
   var builder = new WasmModuleBuilder();
 
   builder.addFunction("main", kSig_i_v)
     .addBody([
       kExprI8Const,
       kReturnValue,
       kExprReturn
     ])
     .exportAs("blah")
     .exportAs("foo");
 
   var module = builder.instantiate();
 
   assertEquals("object", typeof module.exports);
   assertEquals("function", typeof module.exports.blah);
   assertEquals("function", typeof module.exports.foo);
 
   assertEquals(kReturnValue, module.exports.foo());
   assertEquals(kReturnValue, module.exports.blah());
+  assertSame(module.exports.blah, module.exports.foo);
 })();
 
 
 (function testNumericName() {
+  print("TestNumericName...");
   var kReturnValue = 93;
 
   var builder = new WasmModuleBuilder();
 
   builder.addFunction("main", kSig_i_v)
     .addBody([
       kExprI8Const,
       kReturnValue,
       kExprReturn
     ])
     .exportAs("0");
 
   var module = builder.instantiate();
 
   assertEquals("object", typeof module.exports);
   assertEquals("function", typeof module.exports["0"]);
 
   assertEquals(kReturnValue, module.exports["0"]());
 })();
 
 (function testExportNameClash() {
+  print("TestExportNameClash...");
   var builder = new WasmModuleBuilder();
 
   builder.addFunction("one",   kSig_v_v).addBody([kExprNop]).exportAs("main");
   builder.addFunction("two",   kSig_v_v).addBody([kExprNop]).exportAs("other");
   builder.addFunction("three", kSig_v_v).addBody([kExprNop]).exportAs("main");
 
   try {
     builder.instantiate();
     assertUnreachable("should have thrown an exception");
   } catch (e) {
     assertContains("Duplicate export", e.toString());
   }
 })();
+
+
+(function testExportMultipleIdentity() {
+  print("TestExportMultipleIdentity...");
+  var builder = new WasmModuleBuilder();
+
+  builder.addFunction("one", kSig_v_v).addBody([kExprNop])
+    .exportAs("a")
+    .exportAs("b")
+    .exportAs("c");
+
+  let instance = builder.instantiate();
+  let e = instance.exports;
+  assertEquals("function", typeof e.a);
+  assertEquals("function", typeof e.b);
+  assertEquals("function", typeof e.c);
+  assertSame(e.a, e.b);
+  assertSame(e.a, e.c);
+  assertEquals("a", e.a.name);
+})();