Merge "Add thread safety analysis annotations." am: e7ce8c8485 am: f23f21a231 am: a0e5e3abce (d374e3ba) · Commits · e / os / android_system_core

libutils/include/utils/Mutex.h

+72 −21

Original line number	Diff line number	Diff line
		@@ -28,6 +28,53 @@
		#include <utils/Errors.h>
		#include <utils/Timers.h>

		// Enable thread safety attributes only with clang.
		// The attributes can be safely erased when compiling with other compilers.
		#if defined(__clang__) && (!defined(SWIG))
		#define THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x))
		#else
		#define THREAD_ANNOTATION_ATTRIBUTE__(x) // no-op
		#endif

		#define CAPABILITY(x) THREAD_ANNOTATION_ATTRIBUTE__(capability(x))

		#define SCOPED_CAPABILITY THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)

		#define GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))

		#define PT_GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x))

		#define ACQUIRED_BEFORE(...) THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(__VA_ARGS__))

		#define ACQUIRED_AFTER(...) THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(__VA_ARGS__))

		#define REQUIRES(...) THREAD_ANNOTATION_ATTRIBUTE__(requires_capability(__VA_ARGS__))

		#define REQUIRES_SHARED(...) THREAD_ANNOTATION_ATTRIBUTE__(requires_shared_capability(__VA_ARGS__))

		#define ACQUIRE(...) THREAD_ANNOTATION_ATTRIBUTE__(acquire_capability(__VA_ARGS__))

		#define ACQUIRE_SHARED(...) THREAD_ANNOTATION_ATTRIBUTE__(acquire_shared_capability(__VA_ARGS__))

		#define RELEASE(...) THREAD_ANNOTATION_ATTRIBUTE__(release_capability(__VA_ARGS__))

		#define RELEASE_SHARED(...) THREAD_ANNOTATION_ATTRIBUTE__(release_shared_capability(__VA_ARGS__))

		#define TRY_ACQUIRE(...) THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_capability(__VA_ARGS__))

		#define TRY_ACQUIRE_SHARED(...) \
		THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_shared_capability(__VA_ARGS__))

		#define EXCLUDES(...) THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__))

		#define ASSERT_CAPABILITY(x) THREAD_ANNOTATION_ATTRIBUTE__(assert_capability(x))

		#define ASSERT_SHARED_CAPABILITY(x) THREAD_ANNOTATION_ATTRIBUTE__(assert_shared_capability(x))

		#define RETURN_CAPABILITY(x) THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))

		#define NO_THREAD_SAFETY_ANALYSIS THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)

		// ---------------------------------------------------------------------------
		namespace android {
		// ---------------------------------------------------------------------------
		@@ -44,7 +91,7 @@ class Condition;
		* The mutex must be unlocked by the thread that locked it. They are not
		* recursive, i.e. the same thread can't lock it multiple times.
		*/
		class Mutex {
		class CAPABILITY("mutex") Mutex {
		public:
		enum {
		PRIVATE = 0,
		@@ -57,11 +104,11 @@ public:
		~Mutex();

		// lock or unlock the mutex
		status_t lock();
		void unlock();
		status_t lock() ACQUIRE();
		void unlock() RELEASE();

		// lock if possible; returns 0 on success, error otherwise
		status_t tryLock();
		status_t tryLock() TRY_ACQUIRE(true);

		#if defined(__ANDROID__)
		// Lock the mutex, but don't wait longer than timeoutNs (relative time).
		@@ -75,18 +122,22 @@ public:
		// which is subject to NTP adjustments, and includes time during suspend,
		// so a timeout may occur even though no processes could run.
		// Not holding a partial wakelock may lead to a system suspend.
		status_t timedLock(nsecs_t timeoutNs);
		status_t timedLock(nsecs_t timeoutNs) TRY_ACQUIRE(true);
		#endif

		// Manages the mutex automatically. It'll be locked when Autolock is
		// constructed and released when Autolock goes out of scope.
		class Autolock {
		class SCOPED_CAPABILITY Autolock {
		public:
		inline explicit Autolock(Mutex& mutex) : mLock(mutex) { mLock.lock(); }
		inline explicit Autolock(Mutex* mutex) : mLock(*mutex) { mLock.lock(); }
		inline ~Autolock() { mLock.unlock(); }
		inline explicit Autolock(Mutex& mutex) ACQUIRE(mutex) : mLock(mutex) { mLock.lock(); }
		inline explicit Autolock(Mutex* mutex) ACQUIRE(mutex) : mLock(*mutex) { mLock.lock(); }
		inline ~Autolock() RELEASE() { mLock.unlock(); }

		private:
		Mutex& mLock;
		// Cannot be copied or moved - declarations only
		Autolock(const Autolock&);
		Autolock& operator=(const Autolock&);
		};

		private:

libutils/tests/Android.bp

+2 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@ cc_test {
		srcs: [
		"BitSet_test.cpp",
		"LruCache_test.cpp",
		"Mutex_test.cpp",
		"Singleton_test.cpp",
		"String8_test.cpp",
		"StrongPointer_test.cpp",
		@@ -71,6 +72,7 @@ cc_test {
		"-Wall",
		"-Wextra",
		"-Werror",
		"-Wthread-safety",
		],
		}

libutils/tests/Mutex_test.cpp

0 → 100644

+32 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2016 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#include <utils/Mutex.h>

		#include <gtest/gtest.h>

		static android::Mutex mLock;
		static int i GUARDED_BY(mLock);

		void modifyLockedVariable() REQUIRES(mLock) {
		i = 1;
		}

		TEST(Mutex, compile) {
		android::Mutex::Autolock _l(mLock);
		i = 0;
		modifyLockedVariable();
		}
		No newline at end of file