Test that table object indexing does not interfere with backing table

BUG=
R=ahaas@chromium.or

Review-Url: https://codereview.chromium.org/2502383003
Cr-Commit-Position: refs/heads/master@{#41074}

test/mjsunit/wasm/table.js

@@ -55,17 +55,21 @@ function assertTableIsValid(table) {
   assertTableIsValid(table);
   assertEquals(1, table.length);
   assertEquals(null, table.get(0));
+  assertEquals(undefined, table[0]);
 
   table = new WebAssembly.Table({element: "anyfunc", initial: "2"});
   assertTableIsValid(table);
   assertEquals(2, table.length);
   assertEquals(null, table.get(0));
   assertEquals(null, table.get(1));
+  assertEquals(undefined, table[0]);
+  assertEquals(undefined, table[1]);
 
   table = new WebAssembly.Table({element: "anyfunc", initial: {valueOf() { return "1" }}});
   assertTableIsValid(table);
   assertEquals(1, table.length);
   assertEquals(null, table.get(0));
+  assertEquals(undefined, table[0]);
 
   table = new WebAssembly.Table({element: "anyfunc", initial: undefined});
   assertTableIsValid(table);
@@ -160,6 +164,7 @@ function assertTableIsValid(table) {
       assertSame(null, table.get(i));
       assertSame(undefined, table.set(i, f));
       assertSame(f, table.get(i));
+      assertSame(undefined, table[i]);
     }
 
     for (let i = 0; i < table.length; ++i) table.set(i, null);
@@ -167,12 +172,14 @@ function assertTableIsValid(table) {
       assertSame(null, table.get(i));
       assertSame(undefined, table.set(String(i), f));
       assertSame(f, table.get(i));
+      assertSame(undefined, table[i]);
     }
 
     for (let key of [0.4, "", NaN, {}, [], () => {}]) {
       assertSame(undefined, table.set(0, null));
       assertSame(undefined, table.set(key, f));
       assertSame(f, table.get(0));
+      assertSame(undefined, table[key]);
     }
 
     for (let key of [-1, table.length, table.length * 10]) {
@@ -190,6 +197,30 @@ function assertTableIsValid(table) {
   }
 })();
 
+
+(function TestIndexing() {
+  let builder = new WasmModuleBuilder;
+  builder.addExport("wasm", builder.addFunction("", kSig_v_v));
+  builder.addExport("host", builder.addImportWithModule("test", "f", kSig_v_v));
+  let {wasm, host} = builder.instantiate({test: {f() {}}}).exports;
+
+  let table = new WebAssembly.Table({element: "anyfunc", initial: 10});
+
+  for (let f of [wasm, host, () => {}, 5, {}, ""]) {
+    for (let i = 0; i < table.length; ++i) table[i] = f;
+    for (let i = 0; i < table.length; ++i) {
+      assertSame(null, table.get(i));
+      assertSame(f, table[i]);
+    }
+
+    for (let key of [0.4, "", NaN, {}, [], () => {}]) {
+      assertSame(f, table[key] = f);
+      assertSame(f, table[key]);
+      assertSame(null, table.get(key));
+    }
+  }
+})();
+
 (function TestGrow() {
   let builder = new WasmModuleBuilder;
   builder.addExport("wasm", builder.addFunction("", kSig_v_v));