Add function tables to asm to wasm

test/mjsunit/wasm/asm-wasm.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
 
 function EmptyTest() {
   "use asm";
   function caller() {
     empty();
@@ skipping 840 matching lines @@
   function caller() {
     return 55;
   }
   return {alt_caller:caller};
 }
 
 var module = _WASMEXP_.instantiateModuleFromAsm(
     TestExportNameDifferentFromFunctionName.toString());
 module.__init__();
 assertEquals(55, module.alt_caller());
+
+
+function TestFunctionTableSimple() {
+  "use asm";
+
+  function dummy() {
+    return 71;
+  }
+
+  function caller() {
+    return function_table[0&0]() | 0;
+  }
+
+  var function_table = [dummy]
+
+  return {caller:caller};
+}
+
+assertEquals(71, _WASMEXP_.asmCompileRun(TestFunctionTableSimple.toString()));
+
+
+function TestFunctionTable() {
+  "use asm";
+
+  function add(a, b) {
+    a = a|0;
+    b = b|0;
+    return (a+b)|0;
+  }
+
+  function sub(a, b) {
+    a = a|0;
+    b = b|0;
+    return (a-b)|0;
+  }
+
+  function inc(a) {
+    a = a|0;
+    return (a+1)|0;
+  }
+
+  function caller(table_id, fun_id, arg1, arg2) {
+    table_id = table_id|0;
+    fun_id = fun_id|0;
+    arg1 = arg1|0;
+    arg2 = arg2|0;
+    if (table_id == 0) {
+      return funBin[fun_id&3](arg1, arg2)|0;

[bradnelson, 2016/01/20 00:40:52]

Given the parser eats constant function indexes and that needs special handling,
could we also have a test that checks that case?
Thanks

[aseemgarg, 2016/01/20 00:56:09]

Added that above TestFunctionTableSimple

[bradnelson, 2016/01/20 00:57:01]

Doh, missed the test above, though actually might be good to check it works with
a table greater than size 1?

+    } else if (table_id == 1) {
+      return fun[fun_id&0](arg1)|0;
+    }
+    return 0;
+  }
+
+  var funBin = [add, sub, sub, add];
+  var fun = [inc];
+
+  return {caller:caller};
+}
+
+var module = _WASMEXP_.instantiateModuleFromAsm(TestFunctionTable.toString());
+module.__init__();
+assertEquals(55, module.caller(0, 0, 33, 22));
+assertEquals(11, module.caller(0, 1, 33, 22));
+assertEquals(9, module.caller(0, 2, 54, 45));
+assertEquals(99, module.caller(0, 3, 54, 45));
+assertEquals(23, module.caller(0, 4, 12, 11));
+assertEquals(31, module.caller(1, 0, 30, 11));