Add Foreign Functions 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 977 matching lines @@
 }
 
 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));
+
+
+function TestForeignFunctions(stdlib, foreign, buffer) {
+  "use asm";
+
+  var setVal = foreign.setVal;
+  var getVal = foreign.getVal;
+
+  function caller(initial_value, new_value) {
+    initial_value = initial_value|0;
+    new_value = new_value|0;
+    if ((getVal()|0) == (initial_value|0)) {
+      setVal(new_value|0);
+      return getVal()|0;
+    }
+    return 0;
+  }
+
+  return {caller:caller};
+}
+
+function ffi(initial_val) {
+  var val = initial_val;
+
+  function getVal() {
+    return val;
+  }
+
+  function setVal(new_val) {
+    val = new_val;
+  }
+
+  return {getVal:getVal, setVal:setVal};
+}
+
+var foreign = new ffi(23);
+
+var module = _WASMEXP_.instantiateModuleFromAsm(TestForeignFunctions.toString(),
+                                                foreign, null);
+
+module.__init__();
+assertEquals(103, module.caller(23, 103));
+
+
+function TestForeignFunctionMultipleUse(stdlib, foreign, buffer) {
+  "use asm";
+
+  var getVal = foreign.getVal;
+
+  function caller(int_val, double_val) {
+    int_val = int_val|0;
+    double_val = +double_val;
+    if ((getVal()|0) == (int_val|0)) {
+      if ((+getVal()) == (+double_val)) {
+        return 89;
+      }
+    }
+    return 0;
+  }
+
+  return {caller:caller};
+}
+
+function ffii() {

[aseemgarg, 2016/02/05 01:00:01]

If I change the name of this to ffi, the test above (TestForeignFunctions) fails
with:
test/mjsunit/wasm/asm-wasm.js:1035: WasmModule::Instantiate(): FFI function
#3:setVal is not a JSFunction.

[bradnelson, 2016/02/05 01:19:43]

Javascript resolves scoping after parsing everything.
So the last definition wins (but affects calls even before it.

For example:
function foo() { return 3; } console.log(foo()); function foo() { return 4; }
Prints 4

In light of that maybe give these a better name, or for bonus points, wrap the
whole test (both functions) in a function, to give them a separate scope.

[aseemgarg, 2016/02/05 01:33:18]

Done. enclosed in a function

+  function getVal() {
+    return 83.25;
+  }
+
+  return {getVal:getVal};
+}
+
+var foreign = new ffii();
+
+var module = _WASMEXP_.instantiateModuleFromAsm(
+    TestForeignFunctionMultipleUse.toString(), foreign, null);
+
+module.__init__();
+assertEquals(89, module.caller(83, 83.25));