Type profiler by intercepting 'new' and 'delete' expressions.

base/allocator/type_profiler.cc

Index: base/allocator/type_profiler.cc
diff --git a/base/allocator/type_profiler.cc b/base/allocator/type_profiler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d3ced5728343f0cc2217382191391753dfed0f84
--- /dev/null
+++ b/base/allocator/type_profiler.cc
@@ -0,0 +1,62 @@
+// Copyright 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 "base/allocator/type_profiler.h"
+
+#if defined(TYPE_PROFILING)
+
+namespace base {
+namespace type_profiler {
+
+// These variables are not in the InterceptFunctios class so that:

[jar (doing other things), 2012/09/06 19:31:43]

nit: InterceptFunctios --> InterceptFunctions

[Dai Mikurube (NOT FULLTIME), 2012/09/07 08:06:45]

Finally, removed the comment.

+// * They are visible from __op_new_intercept__ and __op_delete_intercept__.
+// * They are invisible from any other functions.

[jar (doing other things), 2012/09/06 19:31:43]

I don't understand why you didn't just make them private, and give friend
function access to the __op* functions.

[Dai Mikurube (NOT FULLTIME), 2012/09/07 08:06:45]

Done.

+//
+// Note that it is impossible to hide them by 'friend'
+// since __op_new_intercept__ and __op_delete_intercept__ must be global.

[jar (doing other things), 2012/09/06 19:31:43]

Global function can be friends.
Nice example in http://en.wikipedia.org/wiki/Friend_function

[Dai Mikurube (NOT FULLTIME), 2012/09/07 08:06:45]

Done.

+static InterceptFunction* g_new_intercept = NopIntercept;
+static InterceptFunction* g_delete_intercept = NopIntercept;
+
+// static
+bool InterceptFunctions::SetFunctions(InterceptFunction* new_intercept,
+                                      InterceptFunction* delete_intercept) {
+#if !defined(NDEBUG)
+  // DCHECKs are wanted for these checks, but base/logging is not acceptable.

[jar (doing other things), 2012/09/06 19:31:43]

It is confusing to have code in base/allocator/*, and then claim you can't use
code in base.  The comment doesn't make sense to me.

If you want to insist on not using code from base, call standard code, such as:

#include <assert.h>

assert(...)

It automatically handles the NDEBUG tests etc.

TCMalloc code often takes this a step further, defining their own raw assert,
but that seems unnecessary here.

[Dai Mikurube (NOT FULLTIME), 2012/09/07 08:06:45]

Done.

+  // This file is linked with many non-Chromium code.
+  if (g_new_intercept != NopIntercept)
+    return false;
+  if (g_delete_intercept != NopIntercept)
+    return false;
+#endif  // !defined(NDEBUG)
+
+  g_new_intercept = new_intercept;
+  g_delete_intercept = delete_intercept;
+  return true;
+}
+
+// static
+bool InterceptFunctions::IsAvailable() {
+  return g_new_intercept != NopIntercept || g_delete_intercept != NopIntercept;
+}
+
+void* NopIntercept(void* ptr, size_t size, const std::type_info& type) {
+  return ptr;
+}
+
+}  // namespace type_profiler
+}  // namespace base
+
+void* __op_new_intercept__(void* ptr,
+                           size_t size,
+                           const std::type_info& type) {
+  return base::type_profiler::g_new_intercept(ptr, size, type);
+}
+
+void* __op_delete_intercept__(void* ptr,
+                              size_t size,
+                              const std::type_info& type) {
+  return base::type_profiler::g_delete_intercept(ptr, size, type);
+}
+
+#endif  // defined(TYPE_PROFILING)