Optimize ToNumber and NonNumberToNumber.

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 774 matching lines @@
 
 // ECMA-262, section 9.3, page 31.
 function ToNumber(x) {
   if (IS_NUMBER(x)) return x;
   if (IS_STRING(x)) {
     return %_HasCachedArrayIndex(x) ? %_GetCachedArrayIndex(x)
                                     : %StringToNumber(x);
   }
   if (IS_BOOLEAN(x)) return x ? 1 : 0;
   if (IS_UNDEFINED(x)) return NAN;
-  if (IS_SYMBOL(x)) throw MakeTypeError(kSymbolToNumber);
-  if (IS_FLOAT32X4(x)) throw MakeTypeError(kSimdToNumber);

[rossberg, 2015/07/28 15:03:19]

Perhaps add a comment explaining the absence of these cases.

[bbudge, 2015/07/28 15:09:51]

Done.

   return (IS_NULL(x)) ? 0 : ToNumber(DefaultNumber(x));
 }
 
 function NonNumberToNumber(x) {
   if (IS_STRING(x)) {
     return %_HasCachedArrayIndex(x) ? %_GetCachedArrayIndex(x)
                                     : %StringToNumber(x);
   }
   if (IS_BOOLEAN(x)) return x ? 1 : 0;
   if (IS_UNDEFINED(x)) return NAN;
-  if (IS_SYMBOL(x)) throw MakeTypeError(kSymbolToNumber);
-  if (IS_FLOAT32X4(x)) throw MakeTypeError(kSimdToNumber);
   return (IS_NULL(x)) ? 0 : ToNumber(DefaultNumber(x));
 }
 
 
 // ECMA-262, section 9.8, page 35.
 function ToString(x) {
   if (IS_STRING(x)) return x;
   if (IS_NUMBER(x)) return %_NumberToString(x);
   if (IS_BOOLEAN(x)) return x ? 'true' : 'false';
   if (IS_UNDEFINED(x)) return 'undefined';
@@ skipping 118 matching lines @@
 function IsConcatSpreadable(O) {
   if (!IS_SPEC_OBJECT(O)) return false;
   var spreadable = O[symbolIsConcatSpreadable];
   if (IS_UNDEFINED(spreadable)) return IS_ARRAY(O);
   return ToBoolean(spreadable);
 }
 
 
 // ECMA-262, section 8.6.2.6, page 28.
 function DefaultNumber(x) {
-  if (!IS_SYMBOL_WRAPPER(x) && !IS_FLOAT32X4_WRAPPER(x)) {
-    var valueOf = x.valueOf;
-    if (IS_SPEC_FUNCTION(valueOf)) {
-      var v = %_CallFunction(x, valueOf);
-      if (IsPrimitive(v)) return v;
-    }
-
-    var toString = x.toString;
-    if (IS_SPEC_FUNCTION(toString)) {
-      var s = %_CallFunction(x, toString);
-      if (IsPrimitive(s)) return s;
-    }
+  var valueOf = x.valueOf;
+  if (IS_SPEC_FUNCTION(valueOf)) {
+    var v = %_CallFunction(x, valueOf);
+    if (IS_SYMBOL(v)) throw MakeTypeError(kSymbolToNumber);
+    if (IS_FLOAT32X4(v)) throw MakeTypeError(kSimdToNumber);
+    if (IsPrimitive(v)) return v;
+  }
+  var toString = x.toString;
+  if (IS_SPEC_FUNCTION(toString)) {
+    var s = %_CallFunction(x, toString);
+    if (IsPrimitive(s)) return s;
   }
   throw MakeTypeError(kCannotConvertToPrimitive);
 }
 
 // ECMA-262, section 8.6.2.6, page 28.
 function DefaultString(x) {
   if (!IS_SYMBOL_WRAPPER(x)) {
     var toString = x.toString;
     if (IS_SPEC_FUNCTION(toString)) {
       var s = %_CallFunction(x, toString);
@@ skipping 40 matching lines @@
 $toLength = ToLength;
 $toName = ToName;
 $toNumber = ToNumber;
 $toObject = ToObject;
 $toPositiveInteger = ToPositiveInteger;
 $toPrimitive = ToPrimitive;
 $toString = ToString;
 $toUint32 = ToUint32;
 
 })