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

base/allocator/allocated_type_control.cc

Index: base/allocator/allocated_type_control.cc
diff --git a/base/allocator/allocated_type_control.cc b/base/allocator/allocated_type_control.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a94994995f332da41a1fa6054ceecc7146572d57
--- /dev/null
+++ b/base/allocator/allocated_type_control.cc
@@ -0,0 +1,36 @@
+// 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 "allocated_type_control.h"
+
+#ifndef USE_ALLOCATED_TYPE

[jar (doing other things), 2012/08/08 23:21:04]

This name seems difficult to parse as you would hope.  It says to "use allocated
type," which doesn't seem meaningful.

Suggest something like:

PROFILING_TYPE_ALLOCATION

You might similarly rename functions to:
StopProfilingTypeAllocation()

IsProfilingTypeAllocation()

Perhaps you should rename the unified file:
type_allocation_profiler.cc

[Dai Mikurube (NOT FULLTIME), 2012/08/09 10:23:54]

I chose

* PROFILING_ALLOCATED_TYPE
* {Stop|Is}ProfilingAllocatedType
* allocated_type_profiler*.{cc|h}

for those.

I keep to use "allocated type" since "allocated type" is a common phrase to
describe "a type of an allocated object".

* http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3376.pdf (p.106)
* http://clang.llvm.org/doxygen/CGCXXABI_8h_source.html#l00219
* http://www.almostinfinite.com/memtrack.html

+
+void StopAllocatedTypeIntercept() {
+  // no operation
+}
+
+bool IsAllocatedTypeInterceptEnabled() {
+  return true;
+}
+
+#else
+
+#include "base/atomicops.h"
+
+volatile static base::subtle::Atomic32 g_enable_intercept = 1;

[jar (doing other things), 2012/08/08 23:21:04]

As noted... please remove the use of atomics, or provide a justification in a
comment, including a reference.

[Dai Mikurube (NOT FULLTIME), 2012/08/09 10:23:54]

Done.

+
+// Stops the interceptors __op_new_intercept__ and __op_delete_intercept__.
+//
+// The interceptors should be stopped at new/delete between fork and exec.
+// See http://crbug.com/36678.
+
+void StopAllocatedTypeIntercept() {
+  base::subtle::NoBarrier_AtomicExchange(&g_enable_intercept, 0);
+}
+
+bool IsAllocatedTypeInterceptEnabled() {
+  return base::subtle::NoBarrier_Load(&g_enable_intercept) != 0;
+}
+
+#endif