[turbofan] Enable tail calls for %_CallFunction.

test/mjsunit/call-runtime-tail.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 --nostress-opt --turbo
+
+var p0 = new Object();
+var p1 = new Object();
+var p2 = new Object();
+
+// Ensure 1 parameter passed straight-through is handled correctly
+var count1 = 100000;
+tailee1 = function() {
+  "use strict";
+  if (count1-- == 0) {
+    return this;
+  }
+  return %_CallFunction(this, tailee1);
+};
+
+%OptimizeFunctionOnNextCall(tailee1);
+assertEquals(p0, tailee1.call(p0));
+
+// Ensure 2 parameters passed straight-through trigger a tail call are handled
+// correctly and don't cause a stack overflow.
+var count2 = 100000;
+tailee2 = function(px) {
+  "use strict";
+  assertEquals(p2, px);
+  assertEquals(p1, this);
+  count2 = ((count2 | 0) - 1) | 0;
+  if ((count2 | 0) === 0) {
+    return this;
+  }
+  return %_CallFunction(this, px, tailee2);
+};
+
+%OptimizeFunctionOnNextCall(tailee2);
+assertEquals(p1, tailee2.call(p1, p2));
+
+// Ensure swapped 2 parameters don't trigger a tail call (parameter swizzling
+// for the tail call isn't supported yet).
+var count3 = 100000;
+tailee3 = function(px) {
+  "use strict";
+  if (count3-- == 0) {
+    return this;
+  }
+  return %_CallFunction(px, this, tailee3);
+};
+
+%OptimizeFunctionOnNextCall(tailee3);
+assertThrows(function() { tailee3.call(p1, p2); });
+
+// Ensure too many parameters defeats the tail call optimization (currently
+// unsupported).
+var count4 = 1000000;
+tailee4 = function(px) {
+  "use strict";
+  if (count4-- == 0) {
+    return this;
+  }
+  return %_CallFunction(this, px, undefined, tailee4);
+};
+
+%OptimizeFunctionOnNextCall(tailee4);
+assertThrows(function() { tailee4.call(p1, p2); });
+
+// Ensure too few parameters defeats the tail call optimization (currently
+// unsupported).
+var count5 = 1000000;
+tailee5 = function(px) {
+  "use strict";
+  if (count5-- == 0) {
+    return this;
+  }
+  return %_CallFunction(this, tailee5);
+};
+
+%OptimizeFunctionOnNextCall(tailee5);
+assertThrows(function() { tailee5.call(p1, p2); });