Change DefaultString and DefaultNumber to match the spec required behavior.

Previously it did two reads of the .toString and .valueOf properties where
only one was allowed.

Review URL: http://codereview.chromium.org/5950001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6047 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/runtime.js

@@ -594,13 +594,15 @@ function IsPrimitive(x) {
 
 // ECMA-262, section 8.6.2.6, page 28.
 function DefaultNumber(x) {
-  if (IS_FUNCTION(x.valueOf)) {
-    var v = x.valueOf();
+  var valueOf = x.valueOf;
+  if (IS_FUNCTION(valueOf)) {
+    var v = %_CallFunction(x, valueOf);
     if (%IsPrimitive(v)) return v;
   }
 
-  if (IS_FUNCTION(x.toString)) {
-    var s = x.toString();
+  var toString = x.toString;
+  if (IS_FUNCTION(toString)) {
+    var s = %_CallFunction(x, toString);
     if (%IsPrimitive(s)) return s;
   }
 
@@ -610,13 +612,15 @@ function DefaultNumber(x) {
 
 // ECMA-262, section 8.6.2.6, page 28.
 function DefaultString(x) {
-  if (IS_FUNCTION(x.toString)) {
-    var s = x.toString();
+  var toString = x.toString;
+  if (IS_FUNCTION(toString)) {
+    var s = %_CallFunction(x, toString);
     if (%IsPrimitive(s)) return s;
   }
 
-  if (IS_FUNCTION(x.valueOf)) {
-    var v = x.valueOf();
+  var valueOf = x.valueOf;
+  if (IS_FUNCTION(valueOf)) {
+    var v = %_CallFunction(x, valueOf);
     if (%IsPrimitive(v)) return v;
   }
 

test/mjsunit/object-toprimitive.js

+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test the ToPrimitive internal function used by ToNumber/ToString.
+// Does it [[Get]] and [[Call]] the object's toString and valueOf properties
+// correctly. Specifically, does it call [[Get]] only once per property.
+
+var o1 = { toString: function() { return 42; },
+           valueOf: function() { return "37"; } };
+var n1 = Number(o1);
+var s1 = String(o1);
+assertTrue(typeof n1 == "number");
+assertTrue(typeof s1 == "string");
+
+var trace = [];
+var valueOfValue = 42;
+var toStringValue = "foo";
+function traceValueOf () {
+  trace.push("vo");
+  return valueOfValue;
+};
+function traceToString() {
+  trace.push("ts");
+  return toStringValue;
+};
+var valueOfFunc = traceValueOf;
+var toStringFunc = traceToString;
+
+var ot = { get toString() { trace.push("gts");
+                            return toStringFunc; },
+           get valueOf() { trace.push("gvo");
+                           return valueOfFunc; }
+};
+
+var nt = Number(ot);
+assertEquals(42, nt);
+assertEquals(["gvo","vo"], trace);
+
+trace = [];
+var st = String(ot);
+assertEquals("foo", st);
+assertEquals(["gts","ts"], trace);
+
+trace = [];
+valueOfValue = ["not primitive"];
+var nt = Number(ot);
+assertEquals(Number("foo"), nt);
+assertEquals(["gvo", "vo", "gts", "ts"], trace);
+
+trace = [];
+valueOfValue = 42;
+toStringValue = ["not primitive"];
+var st = String(ot);
+assertEquals(String(42), st);
+assertEquals(["gts", "ts", "gvo", "vo"], trace);
+
+trace = [];
+valueOfValue = ["not primitive"];
+assertThrows("Number(ot)", TypeError);
+assertEquals(["gvo", "vo", "gts", "ts"], trace);
+
+
+toStringFunc = "not callable";
+trace = [];
+valueOfValue = 42;
+var st = String(ot);
+assertEquals(String(42), st);
+assertEquals(["gts", "gvo", "vo"], trace);
+
+valueOfFunc = "not callable";
+trace = [];
+assertThrows("String(ot)", TypeError);
+assertEquals(["gts", "gvo"], trace);
+
+toStringFunc = traceToString;
+toStringValue = "87";
+trace = [];
+var nt = Number(ot);
+assertEquals(87, nt);
+assertEquals(["gvo", "gts", "ts"], trace);