Reland: Add unoptimized/optimized variants of MathFloor TF code stub

src/runtime.js

 // Copyright 2006-2008 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.
 
 // This files contains runtime support implemented in JavaScript.
 
 // CAUTION: Some of the functions specified in this file are called
 // directly from compiled code. These are the functions with names in
 // ALL CAPS. The compiled code passes the first argument in 'this'.
 
@@ skipping 754 matching lines @@
   return stub;
 }
 
 StringAddTFStub = function StringAddTFStub(call_conv, minor_key) {
   var stub = function(left, right) {
     return %StringAdd(left, right);
   }
   return stub;
 }
 
+const kTurboFanICCallModeMask = 1;
+const kTurboFanICCallForUnptimizedCode = 0;
+const kTurboFanICCallForOptimizedCode = 1;
+
 MathFloorStub = function MathFloorStub(call_conv, minor_key) {
-  var stub = function(f, i, v) {
-    // |f| is calling function's JSFunction
+  var call_from_optimized_ic = function(f, i, tv, receiver, v) {
+    "use strict";
+    // |f| is this function's JSFunction
     // |i| is TypeFeedbackVector slot # of callee's CallIC for Math.floor call
+    // |receiver| is receiver, should not be used
+    // |tv| is the calling function's type vector
     // |v| is the value to floor
+    if (f !== %_FixedArrayGet(tv, i|0)) {
+      return %_CallFunction(receiver, v, f);
+    }
     var r = %_MathFloor(+v);
     if (%_IsMinusZero(r)) {
       // Collect type feedback when the result of the floor is -0. This is
       // accomplished by storing a sentinel in the second, "extra"
       // TypeFeedbackVector slot corresponding to the Math.floor CallIC call in
       // the caller's TypeVector.
-      %_FixedArraySet(%_GetTypeFeedbackVector(f), ((i|0)+1)|0, 1);
+      %_FixedArraySet(tv, ((i|0)+1)|0, 1);

[mvstanton, 2015/07/08 09:42:29]

It would be cool if expressions like ((i|0)+1)|0 could live in a macro,
especially as we create more of these excellent turbofan code stubs.

[danno, 2015/07/08 13:08:40]

Acknowledged.

       return -0;
     }
     // Return integers in smi range as smis.
     var trunc = r|0;
     if (trunc === r) {
       return trunc;
     }
     return r;
   }
-  return stub;
+  var call_mode = (minor_key & kTurboFanICCallModeMask);
+  if (call_mode == kTurboFanICCallForOptimizedCode) {
+    return call_from_optimized_ic;
+  } else {
+    %SetForceInlineFlag(call_from_optimized_ic);
+    var call_from_unoptimized_ic = function(f, i, receiver, v) {
+      var tv = %_GetTypeFeedbackVector(%_GetCallerJSFunction());
+      return call_from_optimized_ic(f, i, tv, receiver, v);
+    }
+    return call_from_unoptimized_ic;
+  }
 }
 
 
 /* -------------------------------------
    - - -   C o n v e r s i o n s   - - -
    -------------------------------------
 */
 
 // ECMA-262, section 9.1, page 30. Use null/undefined for no hint,
 // (1) for number hint, and (2) for string hint.
@@ skipping 234 matching lines @@
 $toLength = ToLength;
 $toName = ToName;
 $toNumber = ToNumber;
 $toObject = ToObject;
 $toPositiveInteger = ToPositiveInteger;
 $toPrimitive = ToPrimitive;
 $toString = ToString;
 $toUint32 = ToUint32;
 
 })