Reverting r4329 due to failure in webkit tests.

src/runtime.cc

 // Copyright 2006-2009 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
@@ skipping 4668 matching lines @@
 
 
 static Object* Runtime_StringParseInt(Arguments args) {
   NoHandleAllocation ha;
 
   CONVERT_CHECKED(String, s, args[0]);
   CONVERT_SMI_CHECKED(radix, args[1]);
 
   s->TryFlatten();
 
-  RUNTIME_ASSERT(radix == 0 || (2 <= radix && radix <= 36));
-  double value = StringToInt(s, radix);
-  return Heap::NumberFromDouble(value);
+  int len = s->length();
+  int i;
+
+  // Skip leading white space.
+  for (i = 0; i < len && Scanner::kIsWhiteSpace.get(s->Get(i)); i++) ;
+  if (i == len) return Heap::nan_value();
+
+  // Compute the sign (default to +).
+  int sign = 1;
+  if (s->Get(i) == '-') {
+    sign = -1;
+    i++;
+  } else if (s->Get(i) == '+') {
+    i++;
+  }
+
+  // Compute the radix if 0.
+  if (radix == 0) {
+    radix = 10;
+    if (i < len && s->Get(i) == '0') {
+      radix = 8;
+      if (i + 1 < len) {
+        int c = s->Get(i + 1);
+        if (c == 'x' || c == 'X') {
+          radix = 16;
+          i += 2;
+        }
+      }
+    }
+  } else if (radix == 16) {
+    // Allow 0x or 0X prefix if radix is 16.
+    if (i + 1 < len && s->Get(i) == '0') {
+      int c = s->Get(i + 1);
+      if (c == 'x' || c == 'X') i += 2;
+    }
+  }
+
+  RUNTIME_ASSERT(2 <= radix && radix <= 36);
+  double value;
+  int end_index = StringToInt(s, i, radix, &value);
+  if (end_index != i) {
+    return Heap::NumberFromDouble(sign * value);
+  }
   return Heap::nan_value();
 }
 
 
 static Object* Runtime_StringParseFloat(Arguments args) {
   NoHandleAllocation ha;
   CONVERT_CHECKED(String, str, args[0]);
 
   // ECMA-262 section 15.1.2.3, empty string is NaN
   double value = StringToDouble(str, ALLOW_TRAILING_JUNK, OS::nan_value());
@@ skipping 5297 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal