keith_miller@apple.com | 6c2ac2e | 2018-03-08 02:26:55 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 Apple Inc. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
| 12 | * |
| 13 | * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' |
| 14 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| 15 | * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 16 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS |
| 17 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 18 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 19 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 20 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 21 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 22 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
| 23 | * THE POSSIBILITY OF SUCH DAMAGE. |
| 24 | */ |
| 25 | |
| 26 | #pragma once |
| 27 | |
| 28 | #include <type_traits> |
| 29 | |
| 30 | namespace WTF { |
| 31 | |
| 32 | template<typename T> |
| 33 | struct FunctionTraits; |
| 34 | |
| 35 | #if USE(JSVALUE32_64) |
| 36 | |
| 37 | template<typename T> |
| 38 | static constexpr unsigned slotsForCCallArgument() |
| 39 | { |
| 40 | static_assert(!std::is_class<T>::value || sizeof(T) <= sizeof(void*), "This doesn't support complex structs."); |
guijemont@igalia.com | 6cd7a41 | 2018-07-04 12:54:48 +0000 | [diff] [blame] | 41 | static_assert(sizeof(T) == 8 || sizeof(T) <= 4, ""); |
keith_miller@apple.com | 6c2ac2e | 2018-03-08 02:26:55 +0000 | [diff] [blame] | 42 | // This assumes that all integral values are passed on the stack. |
| 43 | if (sizeof(T) == 8) |
| 44 | return 2; |
| 45 | |
keith_miller@apple.com | 6c2ac2e | 2018-03-08 02:26:55 +0000 | [diff] [blame] | 46 | return 1; |
| 47 | } |
| 48 | |
| 49 | template<typename T> |
| 50 | static constexpr unsigned computeCCallSlots() { return slotsForCCallArgument<T>(); } |
| 51 | |
| 52 | template<typename T, typename... Ts> |
| 53 | static constexpr std::enable_if_t<!!sizeof...(Ts), unsigned> computeCCallSlots() { return computeCCallSlots<Ts...>() + slotsForCCallArgument<T>(); } |
| 54 | |
| 55 | #endif |
| 56 | |
| 57 | template<typename Result, typename... Args> |
| 58 | struct FunctionTraits<Result(Args...)> { |
| 59 | using ResultType = Result; |
| 60 | |
| 61 | static constexpr bool hasResult = !std::is_same<ResultType, void>::value; |
| 62 | |
| 63 | static constexpr std::size_t arity = sizeof...(Args); |
| 64 | |
| 65 | template <std::size_t n, typename = std::enable_if_t<(n < arity)>> |
| 66 | using ArgumentType = typename std::tuple_element<n, std::tuple<Args...>>::type; |
| 67 | using ArgumentTypes = std::tuple<Args...>; |
| 68 | |
| 69 | |
| 70 | #if USE(JSVALUE64) |
| 71 | static constexpr unsigned cCallArity() { return arity; } |
| 72 | #else |
| 73 | |
| 74 | static constexpr unsigned cCallArity() { return computeCCallSlots<Args...>(); } |
| 75 | #endif // USE(JSVALUE64) |
| 76 | |
| 77 | }; |
| 78 | |
| 79 | template<typename Result, typename... Args> |
| 80 | struct FunctionTraits<Result(*)(Args...)> : public FunctionTraits<Result(Args...)> { |
| 81 | }; |
| 82 | |
| 83 | } // namespace WTF |
| 84 | |
| 85 | using WTF::FunctionTraits; |