tcmalloc_unittest: Use malloc and free directly, instead of tc_malloc and tc_free.

base/allocator/tcmalloc_unittest.cc

 // Copyright (c) 2012 The Chromium 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 <stddef.h>
 #include <stdio.h>
 
+#include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/process/process_metrics.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(USE_TCMALLOC)
-extern "C" {
-void* tc_malloc(size_t size);
-void tc_free(void*);
-}
-
 namespace {
 
 using std::min;
 
 #ifdef NDEBUG
-void* TCMallocDoMallocForTest(size_t size) {
-  return tc_malloc(size);
+// We wrap malloc and free in noinline functions to ensure that we test the real
+// implementation of the allocator. Otherwise, the compiler may specifically
+// recognize the calls to malloc and free in our tests and optimize them away.
+NOINLINE void* TCMallocDoMallocForTest(size_t size) {

[Primiano Tucci (use gerrit), 2016/06/01 20:29:06]

Oh, I would have never thought to this. right.

+  return malloc(size);
 }
 
-void TCMallocDoFreeForTest(void* ptr) {
-  tc_free(ptr);
+NOINLINE void TCMallocDoFreeForTest(void* ptr) {
+  free(ptr);
 }
 #endif
 
 // Fill a buffer of the specified size with a predetermined pattern
 static void Fill(unsigned char* buffer, int n) {
   for (int i = 0; i < n; i++) {
     buffer[i] = (i & 0xff);
   }
 }
 
@@ skipping 176 matching lines @@
   const size_t kPageSize = base::GetPageSize();
   for (size_t size = 1; size <= kPageSize; size <<= 1) {
     char* p = reinterpret_cast<char*>(TCMallocDoMallocForTest(size));
     ASSERT_DEATH(TCMallocDoFreeForTest(p); TCMallocDoFreeForTest(p),
                  "Circular loop in list detected");
   }
 }
 #endif  // NDEBUG
 
 #endif