clang/win: Fix SecurityTest.CallocOverflow in -Os builds.

base/security_unittest.cc

 // Copyright (c) 2013 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 <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ skipping 272 matching lines @@
     scoped_ptr<char[][kArraySize2]> array_pointer(new (nothrow)
         char[kDynamicArraySize][kArraySize2]);
     OverflowTestsSoftExpectTrue(!array_pointer);
   }
 #endif  // !defined(OS_WIN) || !defined(ARCH_CPU_64_BITS)
 }
 
 // Call calloc(), eventually free the memory and return whether or not
 // calloc() did succeed.
 bool CallocReturnsNull(size_t nmemb, size_t size) {
+  // We need the two calls to HideValueFromCompiler(): we have seen LLVM
+  // optimize away the call to calloc() entirely and assume the pointer to not
+  // be NULL.
   scoped_ptr<char, base::FreeDeleter> array_pointer(
-      static_cast<char*>(calloc(nmemb, size)));
-  // We need the call to HideValueFromCompiler(): we have seen LLVM
-  // optimize away the call to calloc() entirely and assume
-  // the pointer to not be NULL.
+      static_cast<char*>(HideValueFromCompiler(calloc(nmemb, size))));
   return HideValueFromCompiler(array_pointer.get()) == NULL;
 }
 
 // Test if calloc() can overflow.
 TEST(SecurityTest, CallocOverflow) {
   const size_t kArraySize = 4096;
   const size_t kMaxSizeT = numeric_limits<size_t>::max();
   const size_t kArraySize2 = kMaxSizeT / kArraySize + 10;
   if (!CallocDiesOnOOM()) {
     EXPECT_TRUE(CallocReturnsNull(kArraySize, kArraySize2));
@@ skipping 59 matching lines @@
   // kRandomMask, so we use it as an additional detection mechanism.
   const uintptr_t kRandomMask = 0x3fffffffffffULL;
   bool impossible_random_address =
       reinterpret_cast<uintptr_t>(ptr.get()) & ~kRandomMask;
   EXPECT_FALSE(impossible_random_address);
 }
 
 #endif  // defined(OS_LINUX) && defined(__x86_64__)
 
 }  // namespace