Add %GetCallerJSFunction intrinsic

test/mjsunit/get-caller-js-function.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: --allow-natives-syntax --always-opt --turbo-filter=* --nostress-opt
+
+// Test that for fully optimized but non inlined code, GetCallerJSFunction walks
+// up a single stack frame to get the calling function. Full optimization elides
+// the check in the runtime version of the intrinsic that would throw since the
+// caller isn't a stub. It's a bit of a hack, but allows minimal testing of the
+// intrinsic without writing a full-blown cctest.
+(function() {
+  var a = function() {
+    return %_GetCallerJSFunction();
+  }

[Michael Starzinger, 2015/06/05 11:21:56]

If we add %OptimizeFunctionOnNextCall(a), could we then get by without having
--always-opt be part of the flags list?

[danno, 2015/06/05 11:49:59]

Done.

+  var b = function() {
+    return a();
+  }
+  assertEquals(b, b());
+}());