1/*
2 * Copyright 2018-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <folly/Portability.h>
20
21// F14 has been implemented for SSE2 and NEON (so far).
22//
23// This platform detection is a bit of a mess because it combines the
24// detection of supported platforms (FOLLY_SSE >= 2 || FOLLY_NEON) with
25// the selection of platforms on which we want to use it.
26//
27// Currently no 32-bit ARM versions are desired because we don't want to
28// need a separate build for chips that don't have NEON. AARCH64 support
29// is enabled for non-mobile platforms, but on mobile platforms there
30// are downstream iteration order effects that have not yet been resolved.
31//
32// If FOLLY_F14_VECTOR_INTRINSICS_AVAILABLE differs across compilation
33// units the program will fail to link due to a missing definition of
34// folly::container::detail::F14LinkCheck<X>::check() for some X.
35#if (FOLLY_SSE >= 2 || (FOLLY_NEON && FOLLY_AARCH64)) && !FOLLY_MOBILE
36#define FOLLY_F14_VECTOR_INTRINSICS_AVAILABLE 1
37#else
38#define FOLLY_F14_VECTOR_INTRINSICS_AVAILABLE 0
39#endif
40
41#if FOLLY_SSE_PREREQ(4, 2) || __ARM_FEATURE_CRC32
42#define FOLLY_F14_CRC_INTRINSIC_AVAILABLE 1
43#else
44#define FOLLY_F14_CRC_INTRINSIC_AVAILABLE 0
45#endif
46
47namespace folly {
48namespace f14 {
49namespace detail {
50
51enum class F14IntrinsicsMode { None, Simd, SimdAndCrc };
52
53static constexpr F14IntrinsicsMode getF14IntrinsicsMode() {
54#if !FOLLY_F14_VECTOR_INTRINSICS_AVAILABLE
55 return F14IntrinsicsMode::None;
56#elif !FOLLY_F14_CRC_INTRINSIC_AVAILABLE
57 return F14IntrinsicsMode::Simd;
58#else
59 return F14IntrinsicsMode::SimdAndCrc;
60#endif
61}
62
63} // namespace detail
64} // namespace f14
65} // namespace folly
66