1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// <vector>
10
11// Make sure we don't miscompile vector operations for types that shouldn't be considered
12// trivially relocatable.
13
14#include <vector>
15#include <cassert>
16#include <cstddef>
17#include <type_traits>
18#include <utility>
19
20#include "test_macros.h"
21
22struct Tracker {
23 std::size_t move_constructs = 0;
24};
25
26struct [[clang::trivial_abi]] Inner {
27 TEST_CONSTEXPR_CXX20 explicit Inner(Tracker* tracker) : tracker_(tracker) {}
28 TEST_CONSTEXPR_CXX20 Inner(const Inner& rhs) : tracker_(rhs.tracker_) { tracker_->move_constructs += 1; }
29 TEST_CONSTEXPR_CXX20 Inner(Inner&& rhs) : tracker_(rhs.tracker_) { tracker_->move_constructs += 1; }
30 Tracker* tracker_;
31};
32
33// Even though this type contains a trivial_abi type, it is not trivially move-constructible,
34// so we should not attempt to optimize its move construction + destroy using trivial relocation.
35struct NotTriviallyMovable {
36 TEST_CONSTEXPR_CXX20 explicit NotTriviallyMovable(Tracker* tracker) : inner_(tracker) {}
37 TEST_CONSTEXPR_CXX20 NotTriviallyMovable(NotTriviallyMovable&& other) : inner_(std::move(other.inner_)) {}
38 Inner inner_;
39};
40static_assert(!std::is_trivially_copyable<NotTriviallyMovable>::value, "");
41LIBCPP_STATIC_ASSERT(!std::__libcpp_is_trivially_relocatable<NotTriviallyMovable>::value, "");
42
43TEST_CONSTEXPR_CXX20 bool tests() {
44 Tracker track;
45 std::vector<NotTriviallyMovable> v;
46
47 // Fill the vector at its capacity, such that any subsequent push_back would require growing.
48 v.reserve(n: 5);
49 std::size_t const capacity = v.capacity(); // could technically be more than 5
50 while (v.size() < v.capacity()) {
51 v.emplace_back(args: &track);
52 }
53 assert(track.move_constructs == 0);
54 assert(v.capacity() == capacity);
55 assert(v.size() == capacity);
56
57 // Force a reallocation of the buffer + relocalization of the elements.
58 // All the existing elements of the vector should be move-constructed to their new location.
59 v.emplace_back(args: &track);
60 assert(track.move_constructs == capacity);
61
62 return true;
63}
64
65int main(int, char**) {
66 tests();
67#if TEST_STD_VER >= 20
68 static_assert(tests());
69#endif
70 return 0;
71}
72

source code of libcxx/test/std/containers/sequences/vector/trivial_relocation.pass.cpp