Add run-time CHECK to smoke-test allocator overrides

third_party/tcmalloc/chromium/src/tcmalloc.cc

 // Copyright (c) 2005, Google Inc.
 // 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
@@ skipping 1372 matching lines @@
   return SpanToMallocResult(span);
 }
 
 // Helpers for use by exported routines below:
 
 inline void do_malloc_stats() {
   PrintStats(1);
 }
 
 inline int do_mallopt(int cmd, int value) {
-  return 1;     // Indicates error
+  if (cmd == TC_MALLOPT_IS_OVERRIDDEN_BY_TCMALLOC)
+    return TC_MALLOPT_IS_OVERRIDDEN_BY_TCMALLOC;
+
+  // 1 is the success return value according to man mallopt(). However (see the
+  // BUGS section in the manpage), most implementations return always 1.
+  // This code is just complying with that (buggy) expectation.
+  return 1;
 }
 
 #ifdef HAVE_STRUCT_MALLINFO
 inline struct mallinfo do_mallinfo() {
   TCMallocStats stats;
   ExtractStats(&stats, NULL, NULL, NULL);
 
   // Just some of the fields are filled in.
   struct mallinfo info;
   memset(&info, 0, sizeof(info));
@@ skipping 492 matching lines @@
   *mark = ~allocated_mark;  //  Distinctively not allocated.
 }
 
 static void MarkAllocatedRegion(void* ptr) {
   if (ptr == NULL) return;
   MarkType* mark = GetMarkLocation(ptr);
   *mark = GetMarkValue(ptr, mark);
 }
 
 #endif  // TCMALLOC_VALIDATION