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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include <iostream>
#include "mongo/platform/atomic_word.h"
#include "mongo/unittest/unittest.h"
namespace mongo {
namespace {
/*
* Modified CAS for AtomicWord to return boolean based on whether or not the swap occurred.
* This helper function mimics the old implementation, which returned the original value of
* expected.
*/
template <typename WordType>
WordType testAtomicWordCompareAndSwap(AtomicWord<WordType>& word,
WordType expected,
WordType desired) {
auto prevWord = word.loadRelaxed();
auto didSwap = word.compareAndSwap(&expected, desired);
ASSERT_EQUALS(expected, prevWord);
if (didSwap) {
ASSERT_EQUALS(word.load(), desired);
} else {
ASSERT_EQUALS(word.load(), prevWord);
}
return expected;
}
template <typename _AtomicWordType>
void testAtomicWordBasicOperations() {
typedef typename _AtomicWordType::WordType WordType;
_AtomicWordType w;
ASSERT_EQUALS(WordType(0), w.load());
w.store(1);
ASSERT_EQUALS(WordType(1), w.load());
ASSERT_EQUALS(WordType(1), w.swap(2));
ASSERT_EQUALS(WordType(2), w.load());
ASSERT_EQUALS(WordType(2), testAtomicWordCompareAndSwap<WordType>(w, 0, 1));
ASSERT_EQUALS(WordType(2), w.load());
ASSERT_EQUALS(WordType(2), testAtomicWordCompareAndSwap<WordType>(w, 2, 1));
ASSERT_EQUALS(WordType(1), w.load());
ASSERT_EQUALS(WordType(1), w.fetchAndAdd(14));
ASSERT_EQUALS(WordType(17), w.addAndFetch(2));
ASSERT_EQUALS(WordType(16), w.subtractAndFetch(1));
ASSERT_EQUALS(WordType(16), w.fetchAndSubtract(1));
ASSERT_EQUALS(WordType(15), testAtomicWordCompareAndSwap<WordType>(w, 15, 0));
ASSERT_EQUALS(WordType(0), w.load());
}
template <typename AtomicWordType>
void testAtomicWordBitOperations() {
typedef typename AtomicWordType::WordType WordType;
AtomicWordType w;
WordType highBit = 1ull << ((sizeof(WordType) * 8) - 1);
w.store(highBit | 0xFFull);
ASSERT_EQUALS(WordType(highBit | 0xFFull), w.fetchAndBitAnd(highBit));
ASSERT_EQUALS(WordType(highBit), w.fetchAndBitOr(highBit | 0xFFull));
ASSERT_EQUALS(WordType(highBit | 0xFFull), w.fetchAndBitXor(0xFFFF));
ASSERT_EQUALS(WordType(highBit | 0xFF00ull), w.load());
}
ASSERT_DOES_NOT_COMPILE(typename T = int, AtomicWord<T>().fetchAndBitAnd(0));
ASSERT_DOES_NOT_COMPILE(typename T = int, AtomicWord<T>().fetchAndBitOr(0));
ASSERT_DOES_NOT_COMPILE(typename T = int, AtomicWord<T>().fetchAndBitXor(0));
ASSERT_DOES_NOT_COMPILE(typename T = char, AtomicWord<T>().fetchAndBitAnd(0));
ASSERT_DOES_NOT_COMPILE(typename T = char, AtomicWord<T>().fetchAndBitOr(0));
ASSERT_DOES_NOT_COMPILE(typename T = char, AtomicWord<T>().fetchAndBitXor(0));
enum TestEnum { E0, E1, E2, E3 };
TEST(AtomicWordTests, BasicOperationsEnum) {
MONGO_STATIC_ASSERT(sizeof(AtomicWord<TestEnum>) == sizeof(TestEnum));
AtomicWord<TestEnum> w;
ASSERT_EQUALS(E0, w.load());
ASSERT_EQUALS(E0, testAtomicWordCompareAndSwap(w, E0, E1));
ASSERT_EQUALS(E1, w.load());
ASSERT_EQUALS(E1, testAtomicWordCompareAndSwap(w, E0, E2));
ASSERT_EQUALS(E1, w.load());
}
TEST(AtomicWordTests, BasicOperationsUnsigned32Bit) {
typedef unsigned WordType;
testAtomicWordBasicOperations<AtomicWord<unsigned>>();
testAtomicWordBitOperations<AtomicWord<unsigned>>();
AtomicWord<unsigned> w(0xdeadbeef);
ASSERT_EQUALS(WordType(0xdeadbeef), testAtomicWordCompareAndSwap<WordType>(w, 0, 1));
ASSERT_EQUALS(WordType(0xdeadbeef),
testAtomicWordCompareAndSwap<WordType>(w, 0xdeadbeef, 0xcafe1234));
ASSERT_EQUALS(WordType(0xcafe1234), w.fetchAndAdd(0xf000));
ASSERT_EQUALS(WordType(0xcaff0234), w.swap(0));
ASSERT_EQUALS(WordType(0), w.load());
}
TEST(AtomicWordTests, BasicOperationsUnsigned64Bit) {
typedef unsigned long long WordType;
testAtomicWordBasicOperations<AtomicWord<unsigned long long>>();
testAtomicWordBitOperations<AtomicWord<unsigned long long>>();
AtomicWord<unsigned long long> w(0xdeadbeefcafe1234ULL);
ASSERT_EQUALS(WordType(0xdeadbeefcafe1234ULL), testAtomicWordCompareAndSwap<WordType>(w, 0, 1));
ASSERT_EQUALS(
WordType(0xdeadbeefcafe1234ULL),
testAtomicWordCompareAndSwap<WordType>(w, 0xdeadbeefcafe1234ULL, 0xfedcba9876543210ULL));
ASSERT_EQUALS(WordType(0xfedcba9876543210ULL), w.fetchAndAdd(0xf0000000ULL));
ASSERT_EQUALS(WordType(0xfedcba9966543210ULL), w.swap(0));
ASSERT_EQUALS(WordType(0), w.load());
}
TEST(AtomicWordTests, BasicOperationsSigned32Bit) {
typedef int WordType;
testAtomicWordBasicOperations<AtomicWord<int>>();
AtomicWord<int> w(0xdeadbeef);
ASSERT_EQUALS(WordType(0xdeadbeef), testAtomicWordCompareAndSwap<WordType>(w, 0, 1));
ASSERT_EQUALS(WordType(0xdeadbeef),
testAtomicWordCompareAndSwap<WordType>(w, 0xdeadbeef, 0xcafe1234));
ASSERT_EQUALS(WordType(0xcafe1234), w.fetchAndAdd(0xf000));
ASSERT_EQUALS(WordType(0xcaff0234), w.swap(0));
ASSERT_EQUALS(WordType(0), w.load());
}
TEST(AtomicWordTests, BasicOperationsSigned64Bit) {
typedef long long WordType;
testAtomicWordBasicOperations<AtomicWord<long long>>();
AtomicWord<long long> w(0xdeadbeefcafe1234ULL);
ASSERT_EQUALS(WordType(0xdeadbeefcafe1234LL), testAtomicWordCompareAndSwap<WordType>(w, 0, 1));
ASSERT_EQUALS(
WordType(0xdeadbeefcafe1234LL),
testAtomicWordCompareAndSwap<WordType>(w, 0xdeadbeefcafe1234LL, 0xfedcba9876543210LL));
ASSERT_EQUALS(WordType(0xfedcba9876543210LL), w.fetchAndAdd(0xf0000000LL));
ASSERT_EQUALS(WordType(0xfedcba9966543210LL), w.swap(0));
ASSERT_EQUALS(WordType(0), w.load());
}
TEST(AtomicWordTests, BasicOperationsFloat) {
typedef AtomicWord<float>::WordType WordType;
AtomicWord<float> w;
ASSERT_EQUALS(WordType(0), w.load());
w.store(1);
ASSERT_EQUALS(WordType(1), w.load());
ASSERT_EQUALS(WordType(1), w.swap(2));
ASSERT_EQUALS(WordType(2), w.load());
ASSERT_EQUALS(WordType(2), testAtomicWordCompareAndSwap<WordType>(w, 0, 1));
ASSERT_EQUALS(WordType(2), w.load());
ASSERT_EQUALS(WordType(2), testAtomicWordCompareAndSwap<WordType>(w, 2, 1));
ASSERT_EQUALS(WordType(1), w.load());
w.store(15);
ASSERT_EQUALS(WordType(15), testAtomicWordCompareAndSwap<WordType>(w, 15, 0));
ASSERT_EQUALS(WordType(0), w.load());
}
struct Chars {
static constexpr size_t kLength = 6;
Chars(const char* chars = "") {
invariant(std::strlen(chars) < kLength);
std::strncpy(_storage.data(), chars, sizeof(_storage));
}
std::array<char, 6> _storage = {};
friend bool operator==(const Chars& lhs, const Chars& rhs) {
return lhs._storage == rhs._storage;
}
friend bool operator!=(const Chars& lhs, const Chars& rhs) {
return !(lhs == rhs);
}
};
std::ostream& operator<<(std::ostream& os, const Chars& chars) {
return (os << chars._storage.data());
}
template <typename T>
void verifyAtomicityHelper() {
ASSERT(std::atomic<T>{}.is_lock_free()); // NOLINT
ASSERT(std::atomic<typename std::make_signed<T>::type>{}.is_lock_free()); // NOLINT
ASSERT(std::atomic<typename std::make_unsigned<T>::type>{}.is_lock_free()); // NOLINT
}
template <typename... Types>
void verifyAtomicity() {
using expander = int[];
(void)expander{(verifyAtomicityHelper<Types>(), 0)...};
}
TEST(AtomicWordTests, StdAtomicOfIntegralIsLockFree) {
// 2 means that they're always atomic. Instead of 1, that means sometimes, and 0, which means
// never.
ASSERT_EQUALS(2, ATOMIC_CHAR_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_CHAR16_T_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_CHAR32_T_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_WCHAR_T_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_SHORT_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_INT_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_LONG_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_LLONG_LOCK_FREE);
ASSERT_EQUALS(2, ATOMIC_POINTER_LOCK_FREE);
verifyAtomicity<char, char16_t, char32_t, wchar_t, short, int, long, long long>();
ASSERT(std::atomic<bool>{}.is_lock_free()); // NOLINT
}
} // namespace
} // namespace mongo
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