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 // UNSUPPORTED: c++03, c++11, c++14, c++17
10
11 // If we have a copy-propagating cache, when we copy ZeroOnDestroy, we will get a
12 // dangling reference to the copied-from object. This test ensures that we do not
13 // propagate the cache on copy.
14
15 #include <ranges>
16
17 #include <cstddef>
18 #include <cstring>
19
20 #include "test_macros.h"
21 #include "types.h"
22
23 struct ZeroOnDestroy : std::ranges::view_base {
24 unsigned count = 0;
25 int buff[8] = {1, 2, 3, 4, 5, 6, 7, 8};
26
beginZeroOnDestroy27 constexpr ForwardIter begin() { return ForwardIter(buff); }
beginZeroOnDestroy28 constexpr ForwardIter begin() const { return ForwardIter(); }
endZeroOnDestroy29 constexpr ForwardIter end() { return ForwardIter(buff + 8); }
endZeroOnDestroy30 constexpr ForwardIter end() const { return ForwardIter(); }
31
32 ZeroOnDestroy() = default;
33 ZeroOnDestroy(const ZeroOnDestroy&) = default;
34 ZeroOnDestroy& operator=(const ZeroOnDestroy&) = default;
~ZeroOnDestroyZeroOnDestroy35 ~ZeroOnDestroy() {
36 std::memset(buff, 0, sizeof(buff));
37 }
38
dropFirstFourZeroOnDestroy39 static auto dropFirstFour() {
40 ZeroOnDestroy zod;
41 std::ranges::drop_view dv(zod, 4);
42 // Make sure we call begin here so the next call to begin will
43 // use the cached iterator.
44 assert(*dv.begin() == 5);
45 // Intentionally invoke the copy ctor here.
46 return std::ranges::drop_view(dv);
47 }
48 };
49
main(int,char **)50 int main(int, char**) {
51 auto noDanglingCache = ZeroOnDestroy::dropFirstFour();
52 // If we use the cached version, it will reference the copied-from view.
53 // Worst case this is a segfault, best case it's an assertion fired.
54 assert(*noDanglingCache.begin() == 5);
55
56 return 0;
57 }
58