| 1 | //===- STLForwardCompat.h - Library features from future STLs ------C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | /// |
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| 9 | /// \file |
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| 10 | /// This file contains library features backported from future STL versions. |
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| 11 | /// |
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| 12 | /// These should be replaced with their STL counterparts as the C++ version LLVM |
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| 13 | /// is compiled with is updated. |
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| 14 | /// |
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| 15 | //===----------------------------------------------------------------------===// |
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| 16 | |
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| 17 | #ifndef LLVM_ADT_STLFORWARDCOMPAT_H |
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| 18 | #define LLVM_ADT_STLFORWARDCOMPAT_H |
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| 19 | |
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| 20 | #include <optional> |
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| 21 | #include <type_traits> |
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| 22 | |
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| 23 | namespace llvm { |
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| 24 | |
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| 25 | //===----------------------------------------------------------------------===// |
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| 26 | // Features from C++20 |
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| 27 | //===----------------------------------------------------------------------===// |
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| 28 | |
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| 29 | template <typename T> |
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| 30 | struct remove_cvref // NOLINT(readability-identifier-naming) |
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| 31 | { |
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| 32 | using type = std::remove_cv_t<std::remove_reference_t<T>>; |
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| 33 | }; |
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| 34 | |
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| 35 | template <typename T> |
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| 36 | using remove_cvref_t // NOLINT(readability-identifier-naming) |
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| 37 | = typename llvm::remove_cvref<T>::type; |
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| 38 | |
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| 39 | //===----------------------------------------------------------------------===// |
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| 40 | // Features from C++23 |
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| 41 | //===----------------------------------------------------------------------===// |
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| 42 | |
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| 43 | // TODO: Remove this in favor of std::optional<T>::transform once we switch to |
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| 44 | // C++23. |
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| 45 | template <typename T, typename Function> |
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| 46 | auto transformOptional(const std::optional<T> &O, const Function &F) |
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| 47 | -> std::optional<decltype(F(*O))> { |
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| 48 | if (O) |
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| 49 | return F(*O); |
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| 50 | return std::nullopt; |
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| 51 | } |
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| 52 | |
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| 53 | // TODO: Remove this in favor of std::optional<T>::transform once we switch to |
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| 54 | // C++23. |
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| 55 | template <typename T, typename Function> |
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| 56 | auto transformOptional(std::optional<T> &&O, const Function &F) |
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| 57 | -> std::optional<decltype(F(*std::move(O)))> { |
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| 58 | if (O) |
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| 59 | return F(*std::move(O)); |
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| 60 | return std::nullopt; |
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| 61 | } |
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| 62 | |
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| 63 | } // namespace llvm |
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| 64 | |
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| 65 | #endif // LLVM_ADT_STLFORWARDCOMPAT_H |
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| 66 | |
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