/*-
 * Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
#include <assert.h>
#include <stdatomic.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

/*
 * Tool for testing the logical behaviour of operations on atomic
 * integer types. These tests make no attempt to actually test whether
 * the functions are atomic or provide the right barrier semantics.
 *
 * For every type, we create an array of 16 elements and repeat the test
 * on every element in the array. This allows us to test whether the
 * atomic operations have no effect on surrounding values. This is
 * especially useful for the smaller integer types, as it may be the
 * case that these operations are implemented by processing entire words
 * (e.g. on MIPS).
 *
 * Before the randomised loop, a small surface check exercises lock-free
 * macros, fences, atomic_flag, atomic_bool, pointer fetch_add/fetch_sub
 * stride, kill_dependency, atomic_is_lock_free, and when available
 * ATOMIC_VAR_INIT / ATOMIC_FLAG_INIT (pre-C23).
 */

#define CHECK_LOCK_FREE(name)                                           \
        _Static_assert((name) == 0 || (name) == 1 || (name) == 2,       \
            #name " out of range")

CHECK_LOCK_FREE(ATOMIC_BOOL_LOCK_FREE);
CHECK_LOCK_FREE(ATOMIC_CHAR_LOCK_FREE);
CHECK_LOCK_FREE(ATOMIC_SHORT_LOCK_FREE);
CHECK_LOCK_FREE(ATOMIC_INT_LOCK_FREE);
CHECK_LOCK_FREE(ATOMIC_LONG_LOCK_FREE);
CHECK_LOCK_FREE(ATOMIC_LLONG_LOCK_FREE);
CHECK_LOCK_FREE(ATOMIC_POINTER_LOCK_FREE);
#ifdef ATOMIC_CHAR8_T_LOCK_FREE
CHECK_LOCK_FREE(ATOMIC_CHAR8_T_LOCK_FREE);
#endif
#ifdef ATOMIC_CHAR16_T_LOCK_FREE
CHECK_LOCK_FREE(ATOMIC_CHAR16_T_LOCK_FREE);
#endif
#ifdef ATOMIC_CHAR32_T_LOCK_FREE
CHECK_LOCK_FREE(ATOMIC_CHAR32_T_LOCK_FREE);
#endif
#ifdef ATOMIC_WCHAR_T_LOCK_FREE
CHECK_LOCK_FREE(ATOMIC_WCHAR_T_LOCK_FREE);
#endif

#if defined(__STDC_VERSION_STDATOMIC_H__)
_Static_assert(__STDC_VERSION_STDATOMIC_H__ == 202311L,
    "__STDC_VERSION_STDATOMIC_H__");
#endif

static void
test_surface(void)
{
        atomic_flag f = ATOMIC_FLAG_INIT;
        atomic_int probe;
        atomic_bool b;
        _Atomic(int *) ap;
        int arr[4];
        int dep;
        static const memory_order k_orders[] = {
                memory_order_relaxed,
                memory_order_consume,
                memory_order_acquire,
                memory_order_release,
                memory_order_acq_rel,
                memory_order_seq_cst,
        };
        size_t k;

        dep = kill_dependency(123);
        assert(dep == 123);

        atomic_init(&probe, 0);
        assert(atomic_is_lock_free(&probe) ==
            atomic_is_lock_free((atomic_int *)NULL));

        for (k = 0; k < sizeof(k_orders) / sizeof(k_orders[0]); k++) {
                atomic_thread_fence(k_orders[k]);
                atomic_signal_fence(k_orders[k]);
        }

        assert(atomic_flag_test_and_set_explicit(&f,
            memory_order_seq_cst) == 0);
        assert(atomic_flag_test_and_set_explicit(&f,
            memory_order_acquire) != 0);
        atomic_flag_clear_explicit(&f, memory_order_relaxed);

        atomic_init(&b, false);
        atomic_store_explicit(&b, true, memory_order_relaxed);
        assert(atomic_load_explicit(&b, memory_order_relaxed) == true);

        memset(arr, 0, sizeof(arr));
        atomic_init(&ap, &arr[3]);
        atomic_fetch_sub_explicit(&ap, 2, memory_order_relaxed);
        assert(ap == &arr[1]);
        atomic_fetch_add_explicit(&ap, 1, memory_order_relaxed);
        assert(ap == &arr[2]);
}

#ifdef ATOMIC_VAR_INIT
static void
test_atomic_var_init(void)
{
        atomic_int x = ATOMIC_VAR_INIT(42);

        assert(atomic_load_explicit(&x, memory_order_relaxed) == 42);
        atomic_store_explicit(&x, 7, memory_order_relaxed);
        assert(atomic_load_explicit(&x, memory_order_relaxed) == 7);

        {
                atomic_flag f = ATOMIC_FLAG_INIT;

                assert(atomic_flag_test_and_set_explicit(&f,
                    memory_order_seq_cst) == 0);
                atomic_flag_clear_explicit(&f, memory_order_relaxed);
        }
}
#endif

static inline intmax_t
rndnum(void)
{
        intmax_t v;

        arc4random_buf(&v, sizeof(v));
        return (v);
}

#define DO_FETCH_TEST(T, a, name, result) do {                          \
        T v1 = atomic_load(a);                                          \
        T v2 = rndnum();                                                \
        assert(atomic_##name(a, v2) == v1);                             \
        assert(atomic_load(a) == (T)(result));                          \
} while (0)

#define DO_COMPARE_EXCHANGE_TEST(T, a, name) do {                       \
        T v1 = atomic_load(a);                                          \
        T v2 = rndnum();                                                \
        T v3 = rndnum();                                                \
        if (atomic_compare_exchange_##name(a, &v2, v3))                 \
                assert(v1 == v2);                                       \
        else                                                            \
                assert(atomic_compare_exchange_##name(a, &v2, v3));     \
        assert(atomic_load(a) == v3);                                   \
} while (0)

#define DO_ALL_TESTS(T, a) do {                                         \
        {                                                               \
                T v1 = rndnum();                                        \
                atomic_init(a, v1);                                     \
                assert(atomic_load(a) == v1);                           \
        }                                                               \
        {                                                               \
                T v1 = rndnum();                                        \
                atomic_store(a, v1);                                    \
                assert(atomic_load(a) == v1);                           \
        }                                                               \
                                                                        \
        DO_FETCH_TEST(T, a, exchange, v2);                              \
        DO_FETCH_TEST(T, a, fetch_add, v1 + v2);                        \
        DO_FETCH_TEST(T, a, fetch_and, v1 & v2);                        \
        DO_FETCH_TEST(T, a, fetch_or, v1 | v2);                         \
        DO_FETCH_TEST(T, a, fetch_sub, v1 - v2);                        \
        DO_FETCH_TEST(T, a, fetch_xor, v1 ^ v2);                        \
                                                                        \
        DO_COMPARE_EXCHANGE_TEST(T, a, weak);                           \
        DO_COMPARE_EXCHANGE_TEST(T, a, strong);                         \
} while (0)

#define TEST_TYPE(T) do {                                               \
        int j;                                                          \
        struct { _Atomic(T) v[16]; } list, cmp;                         \
        arc4random_buf(&cmp, sizeof(cmp));                              \
        for (j = 0; j < 16; j++) {                                      \
                list = cmp;                                             \
                DO_ALL_TESTS(T, &list.v[j]);                            \
                list.v[j] = cmp.v[j];                                   \
                assert(memcmp(&list, &cmp, sizeof(list)) == 0);         \
        }                                                               \
} while (0)

int
main(void)
{
        int i;

        test_surface();
#ifdef ATOMIC_VAR_INIT
        test_atomic_var_init();
#endif
        for (i = 0; i < 1000; i++) {
                TEST_TYPE(int8_t);
                TEST_TYPE(uint8_t);
                TEST_TYPE(int16_t);
                TEST_TYPE(uint16_t);
                TEST_TYPE(int32_t);
                TEST_TYPE(uint32_t);
                TEST_TYPE(int64_t);
                TEST_TYPE(uint64_t);
        }

        return (0);
}