Avoid calling memchr with a zero range as this is undefined behavior.

src/runtime.cc

 // Copyright 2012 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.
 
 #include <stdlib.h>
 #include <limits>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
@@ skipping 3585 matching lines @@
                             char pattern,
                             ZoneList<int>* indices,
                             unsigned int limit,
                             Zone* zone) {
   ASSERT(limit > 0);
   // Collect indices of pattern in subject using memchr.
   // Stop after finding at most limit values.
   const uint8_t* subject_start = subject.start();
   const uint8_t* subject_end = subject_start + subject.length();
   const uint8_t* pos = subject_start;
-  while (limit > 0) {
+  while ((limit > 0) && (subject_end > pos)) {
     pos = reinterpret_cast<const uint8_t*>(
         memchr(pos, pattern, subject_end - pos));
     if (pos == NULL) return;
     indices->Add(static_cast<int>(pos - subject_start), zone);
     pos++;
     limit--;
   }
 }
 
 
@@ skipping 11468 matching lines @@
   }
   return NULL;
 }
 
 
 const Runtime::Function* Runtime::FunctionForId(Runtime::FunctionId id) {
   return &(kIntrinsicFunctions[static_cast<int>(id)]);
 }
 
 } }  // namespace v8::internal