Upgrade gperftools to 2.9 for GCP/GMC/GMP/GMD. (#2247)

trunk/3rdparty/gperftools-2-fit/src/base/thread_annotations.h

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+// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
+// Copyright (c) 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Le-Chun Wu
+//
+// This header file contains the macro definitions for thread safety
+// annotations that allow the developers to document the locking policies
+// of their multi-threaded code. The annotations can also help program
+// analysis tools to identify potential thread safety issues.
+//
+// The annotations are implemented using clang's "attributes" extension.
+// Using the macros defined here instead of the raw clang attributes allows
+// for portability and future compatibility.
+//
+// This functionality is not yet fully implemented in perftools,
+// but may be one day.
+
+#ifndef BASE_THREAD_ANNOTATIONS_H_
+#define BASE_THREAD_ANNOTATIONS_H_
+
+
+#if defined(__clang__)
+#define THREAD_ANNOTATION_ATTRIBUTE__(x)   __attribute__((x))
+#else
+#define THREAD_ANNOTATION_ATTRIBUTE__(x)   // no-op
+#endif
+
+
+// Document if a shared variable/field needs to be protected by a lock.
+// GUARDED_BY allows the user to specify a particular lock that should be
+// held when accessing the annotated variable, while GUARDED_VAR only
+// indicates a shared variable should be guarded (by any lock). GUARDED_VAR
+// is primarily used when the client cannot express the name of the lock.
+#define GUARDED_BY(x)          THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
+#define GUARDED_VAR            THREAD_ANNOTATION_ATTRIBUTE__(guarded)
+
+// Document if the memory location pointed to by a pointer should be guarded
+// by a lock when dereferencing the pointer. Similar to GUARDED_VAR,
+// PT_GUARDED_VAR is primarily used when the client cannot express the name
+// of the lock. Note that a pointer variable to a shared memory location
+// could itself be a shared variable. For example, if a shared global pointer
+// q, which is guarded by mu1, points to a shared memory location that is
+// guarded by mu2, q should be annotated as follows:
+//     int *q GUARDED_BY(mu1) PT_GUARDED_BY(mu2);
+#define PT_GUARDED_BY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(point_to_guarded_by(x))
+#define PT_GUARDED_VAR \
+  THREAD_ANNOTATION_ATTRIBUTE__(point_to_guarded)
+
+// Document the acquisition order between locks that can be held
+// simultaneously by a thread. For any two locks that need to be annotated
+// to establish an acquisition order, only one of them needs the annotation.
+// (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER
+// and ACQUIRED_BEFORE.)
+#define ACQUIRED_AFTER(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x))
+#define ACQUIRED_BEFORE(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x))
+
+// The following three annotations document the lock requirements for
+// functions/methods.
+
+// Document if a function expects certain locks to be held before it is called
+#define EXCLUSIVE_LOCKS_REQUIRED(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(x))
+
+#define SHARED_LOCKS_REQUIRED(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(x))
+
+// Document the locks acquired in the body of the function. These locks
+// cannot be held when calling this function (as google3's Mutex locks are
+// non-reentrant).
+#define LOCKS_EXCLUDED(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(x))
+
+// Document the lock the annotated function returns without acquiring it.
+#define LOCK_RETURNED(x)       THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
+
+// Document if a class/type is a lockable type (such as the Mutex class).
+#define LOCKABLE               THREAD_ANNOTATION_ATTRIBUTE__(lockable)
+
+// Document if a class is a scoped lockable type (such as the MutexLock class).
+#define SCOPED_LOCKABLE        THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
+
+// The following annotations specify lock and unlock primitives.
+#define EXCLUSIVE_LOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock_function(x))
+
+#define SHARED_LOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(shared_lock_function(x))
+
+#define EXCLUSIVE_TRYLOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock_function(x))
+
+#define SHARED_TRYLOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock_function(x))
+
+#define UNLOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(unlock_function(x))
+
+// An escape hatch for thread safety analysis to ignore the annotated function.
+#define NO_THREAD_SAFETY_ANALYSIS \
+  THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
+
+#endif  // BASE_THREAD_ANNOTATIONS_H_