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

base/allocator/allocated_type_profiler_control.cc

Index: base/allocator/allocated_type_profiler_control.cc
diff --git a/base/allocator/allocated_type_profiler_control.cc b/base/allocator/allocated_type_profiler_control.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3636d3a523368b7f97a0be374cb19edfd4f8f000
--- /dev/null
+++ b/base/allocator/allocated_type_profiler_control.cc
@@ -0,0 +1,34 @@
+// 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/allocated_type_profiler_control.h"
+
+#if defined(PROFILING_ALLOCATED_TYPE)
+static int g_enable_intercept = 1;
+#endif
+
+namespace base {
+namespace allocated_type {

[jar (doing other things), 2012/08/23 19:55:25]

nit: we don't "allocate types," so this namespace seems to drop the interesting
word "profiler" and keep the less significant word "allocated."  Please
consider:

type_profiler

[Dai Mikurube (NOT FULLTIME), 2012/08/24 02:47:27]

Renamed it to allocated_type_profiler.

As I said before, "allocated type" is a very common phrase to describe "a type
of an allocated object".  So keeping "allocated" is reasonable.

* 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

[jar (doing other things), 2012/08/27 17:17:12]

I will remove the courtesy of calling this a nit, which I have used up to this
point.

I don't believe it is a nit, as it is damaging readability.

The namespace name must be small enough to not dominate the line, and
consistently cause lines to wrap.  The commonly seen:

base::allocated_type_profiler

is too long, and uncessarily so.  The shortened version:

base::allocated_type

maintains a meaningless qualifier, and discards critical information (that this
is about profiling).

When a reader see "allocated_type" the presumption is that both words are
critical, and hence there is probably an "unallocated_type" as well somewhere.
There is no such thing, and that it why the refinement to say "allocated" is
pretty useless, but the refinement to say "*_profiler" is extremely valuable.

A much better name is "type_profiler".

The references to technical publications, which are not under pressure to be
concise, is not significant readability in C++.

Please change this throughout to "type_profile," as I have asked repeatedly.

On 2012/08/24 02:47:27, Dai Mikurube wrote:

[Dai Mikurube (NOT FULLTIME), 2012/08/27 23:52:56]

Ok, I'll rename the namespace to type_profiler.  Is that enough?

[Dai Mikurube (NOT FULLTIME), 2012/08/28 09:04:57]

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.

[jar (doing other things), 2012/08/23 19:55:25]

nit: This comment should probably only be placed at the call site.

[Dai Mikurube (NOT FULLTIME), 2012/08/24 02:47:27]

Done.  Moved it to the callsite, base/process_util_posix.cc.

+
+void StopProfilingAllocatedType() {
+#if defined(PROFILING_ALLOCATED_TYPE)
+  g_enable_intercept = 0;
+#endif
+}
+
+bool IsProfilingAllocatedType() {
+#if defined(PROFILING_ALLOCATED_TYPE)
+  return g_enable_intercept != 0;
+#else
+  return false;
+#endif
+}
+
+}  // namespace allocated_type
+}  // namespace base