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[libc++] Fix ambiguity when using std::scoped_allocator constructor #80020

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[libc++] Fix ambiguity when using std::scoped_allocator constructor #80020

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28 changes: 16 additions & 12 deletions libcxx/include/scoped_allocator
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Original file line number Diff line number Diff line change
Expand Up @@ -197,6 +197,8 @@ struct __get_is_always_equal<_A0, _Allocs...> {
static const bool value = allocator_traits<_A0>::is_always_equal::value && __get_is_always_equal<_Allocs...>::value;
};

struct __chained_ctor_tag {};
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Can you add some comment to this tag, preferably referring to the bug it fixes.


template <class... _Allocs>
class __scoped_allocator_storage;

Expand Down Expand Up @@ -249,6 +251,7 @@ protected:
scoped_allocator_adaptor<outer_allocator_type, _InnerAllocs...> _LIBCPP_HIDE_FROM_ABI
select_on_container_copy_construction() const _NOEXCEPT {
return scoped_allocator_adaptor<outer_allocator_type, _InnerAllocs...>(
__chained_ctor_tag(),
allocator_traits<outer_allocator_type>::select_on_container_copy_construction(outer_allocator()),
allocator_traits<inner_allocator_type>::select_on_container_copy_construction(inner_allocator()));
}
Expand Down Expand Up @@ -334,12 +337,12 @@ struct __outermost<_Alloc, true> {
template <class _OuterAlloc, class... _InnerAllocs>
class _LIBCPP_TEMPLATE_VIS scoped_allocator_adaptor<_OuterAlloc, _InnerAllocs...>
: public __scoped_allocator_storage<_OuterAlloc, _InnerAllocs...> {
typedef __scoped_allocator_storage<_OuterAlloc, _InnerAllocs...> base;
typedef __scoped_allocator_storage<_OuterAlloc, _InnerAllocs...> _Base;
typedef allocator_traits<_OuterAlloc> _OuterTraits;

public:
typedef _OuterAlloc outer_allocator_type;
typedef typename base::inner_allocator_type inner_allocator_type;
typedef typename _Base::inner_allocator_type inner_allocator_type;
typedef typename _OuterTraits::size_type size_type;
typedef typename _OuterTraits::difference_type difference_type;
typedef typename _OuterTraits::pointer pointer;
Expand All @@ -365,29 +368,29 @@ public:
template <class _OuterA2, __enable_if_t<is_constructible<outer_allocator_type, _OuterA2>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI
scoped_allocator_adaptor(_OuterA2&& __outer_alloc, const _InnerAllocs&... __inner_allocs) _NOEXCEPT
: base(std::forward<_OuterA2>(__outer_alloc), __inner_allocs...) {}
: _Base(std::forward<_OuterA2>(__outer_alloc), __inner_allocs...) {}
// scoped_allocator_adaptor(const scoped_allocator_adaptor& __other) = default;
template <class _OuterA2, __enable_if_t<is_constructible<outer_allocator_type, const _OuterA2&>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI
scoped_allocator_adaptor(const scoped_allocator_adaptor<_OuterA2, _InnerAllocs...>& __other) _NOEXCEPT
: base(__other) {}
: _Base(__other) {}
template <class _OuterA2, __enable_if_t<is_constructible<outer_allocator_type, _OuterA2>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI
scoped_allocator_adaptor(scoped_allocator_adaptor<_OuterA2, _InnerAllocs...>&& __other) _NOEXCEPT
: base(std::move(__other)) {}
: _Base(std::move(__other)) {}

// scoped_allocator_adaptor& operator=(const scoped_allocator_adaptor&) = default;
// scoped_allocator_adaptor& operator=(scoped_allocator_adaptor&&) = default;
// ~scoped_allocator_adaptor() = default;

_LIBCPP_HIDE_FROM_ABI inner_allocator_type& inner_allocator() _NOEXCEPT { return base::inner_allocator(); }
_LIBCPP_HIDE_FROM_ABI inner_allocator_type& inner_allocator() _NOEXCEPT { return _Base::inner_allocator(); }
_LIBCPP_HIDE_FROM_ABI const inner_allocator_type& inner_allocator() const _NOEXCEPT {
return base::inner_allocator();
return _Base::inner_allocator();
}

_LIBCPP_HIDE_FROM_ABI outer_allocator_type& outer_allocator() _NOEXCEPT { return base::outer_allocator(); }
_LIBCPP_HIDE_FROM_ABI outer_allocator_type& outer_allocator() _NOEXCEPT { return _Base::outer_allocator(); }
_LIBCPP_HIDE_FROM_ABI const outer_allocator_type& outer_allocator() const _NOEXCEPT {
return base::outer_allocator();
return _Base::outer_allocator();
}

_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI pointer allocate(size_type __n) {
Expand Down Expand Up @@ -472,13 +475,14 @@ public:
}

_LIBCPP_HIDE_FROM_ABI scoped_allocator_adaptor select_on_container_copy_construction() const _NOEXCEPT {
return base::select_on_container_copy_construction();
return _Base::select_on_container_copy_construction();
}

private:
template <class _OuterA2, __enable_if_t<is_constructible<outer_allocator_type, _OuterA2>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI scoped_allocator_adaptor(_OuterA2&& __o, const inner_allocator_type& __i) _NOEXCEPT
: base(std::forward<_OuterA2>(__o), __i) {}
_LIBCPP_HIDE_FROM_ABI
scoped_allocator_adaptor(__chained_ctor_tag, _OuterA2&& __o, const inner_allocator_type& __i) _NOEXCEPT
: _Base(std::forward<_OuterA2>(__o), __i) {}

template <class _Tp, class... _Args>
_LIBCPP_HIDE_FROM_ABI void __construct(integral_constant<int, 0>, _Tp* __p, _Args&&... __args) {
Expand Down
14 changes: 13 additions & 1 deletion libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,9 @@
// scoped_allocator_adaptor(OuterA2&& outerAlloc,
// const InnerAllocs& ...innerAllocs);

#include <scoped_allocator>
#include <cassert>
#include <memory_resource>
#include <scoped_allocator>

#include "test_macros.h"
#include "allocators.h"
Expand Down Expand Up @@ -111,6 +112,17 @@ int main(int, char**) {
!std::is_convertible< std::scoped_allocator_adaptor<A1<int>>, std::scoped_allocator_adaptor<A2<int>>>::value,
"");
}
{
// https://github.com/llvm/llvm-project/issues/78754
using PA = std::pmr::polymorphic_allocator<int>;
std::pmr::monotonic_buffer_resource mr1;
std::pmr::monotonic_buffer_resource mr2;

using A = std::scoped_allocator_adaptor<PA, PA>;
A a(&mr1, &mr2);
assert(a.outer_allocator().resource() == &mr1);
assert(a.inner_allocator().resource() == &mr2);
}

return 0;
}
27 changes: 27 additions & 0 deletions libcxx/test/std/utilities/allocator.adaptor/base-is-uglified.compile.pass.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03

// <memory>

// This test ensures that we don't use a non-uglified name 'base' in the
// implementation of scoped_allcoator_adaptor.
//
// See https://github.com/llvm/llvm-project/issues/78754.

#include <memory>
#include <scoped_allocator>

using ScopedAlloc = std::scoped_allocator_adaptor<std::allocator<int>, std::allocator<int>>;
struct MyBase {
using base = MyBase;
};
struct MyDerived : ScopedAlloc, MyBase {};

using T = MyDerived::base; // Should be well-formed