60 lines
1.4 KiB
C++
60 lines
1.4 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Copyright 2024 Bloomberg Finance L.P.
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03 || c++11 || c++14 || c++17 || c++20
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// ADDITIONAL_COMPILE_FLAGS: -freflection
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// ADDITIONAL_COMPILE_FLAGS: -Wno-inconsistent-missing-override
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// <experimental/reflection>
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//
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// [reflection]
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#include <meta>
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#include <array>
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#include <cstdlib>
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#include <print>
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struct member_descriptor
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{
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std::size_t offset;
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std::size_t size;
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};
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// returns std::array<member_descriptor, N>
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template <typename S>
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consteval auto get_layout() {
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constexpr auto ctx = std::meta::access_context::current();
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auto members = nonstatic_data_members_of(^^S, ctx);
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constexpr size_t sz = nonstatic_data_members_of(^^S, ctx).size();
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std::array<member_descriptor, sz> layout;
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for (int i = 0; i < members.size(); ++i) {
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layout[i] = {
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.offset=static_cast<std::size_t>(offset_of(members[i]).bytes),
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.size=size_of(members[i])
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};
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}
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return layout;
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}
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struct X
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{
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char a;
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int b;
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double c;
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};
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int main() {
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for (const auto &md : get_layout<X>())
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std::println("({}, {})", md.offset, md.size);
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}
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