PR libstdc++/70966 make pmr::new_delete_resource() immortal
Construct the program-wide resource objects using placement new. This means they have dynamic storage duration and won't be destroyed during termination. PR libstdc++/70966 * include/experimental/memory_resource (__resource_adaptor_imp): Add static assertions to enforce requirements on pointer types. (__resource_adaptor_imp::get_allocator()): Add noexcept. (new_delete_resource, null_memory_resource): Return address of an object with dynamic storage duration. (__null_memory_resource): Remove. * testsuite/experimental/memory_resource/70966.cc: New. From-SVN: r261818
This commit is contained in:
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c145665684
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@ -1,5 +1,14 @@
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2018-06-20 Jonathan Wakely <jwakely@redhat.com>
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PR libstdc++/70966
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* include/experimental/memory_resource (__resource_adaptor_imp): Add
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static assertions to enforce requirements on pointer types.
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(__resource_adaptor_imp::get_allocator()): Add noexcept.
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(new_delete_resource, null_memory_resource): Return address of an
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object with dynamic storage duration.
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(__null_memory_resource): Remove.
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* testsuite/experimental/memory_resource/70966.cc: New.
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* testsuite/20_util/duration/arithmetic/dr3050.cc: Add new test
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missed from recent commit.
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@ -33,7 +33,6 @@
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#include <new>
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#include <atomic>
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#include <cstddef>
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#include <bits/alloc_traits.h>
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#include <experimental/bits/lfts_config.h>
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namespace std {
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@ -258,6 +257,22 @@ namespace pmr {
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template <typename _Alloc>
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class __resource_adaptor_imp : public memory_resource
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{
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static_assert(is_same<char,
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typename allocator_traits<_Alloc>::value_type>::value,
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"Allocator's value_type is char");
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static_assert(is_same<char*,
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typename allocator_traits<_Alloc>::pointer>::value,
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"Allocator's pointer type is value_type*");
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static_assert(is_same<const char*,
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typename allocator_traits<_Alloc>::const_pointer>::value,
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"Allocator's const_pointer type is value_type const*");
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static_assert(is_same<void*,
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typename allocator_traits<_Alloc>::void_pointer>::value,
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"Allocator's void_pointer type is void*");
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static_assert(is_same<const void*,
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typename allocator_traits<_Alloc>::const_void_pointer>::value,
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"Allocator's const_void_pointer type is void const*");
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public:
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using allocator_type = _Alloc;
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@ -276,7 +291,7 @@ namespace pmr {
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__resource_adaptor_imp&
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operator=(const __resource_adaptor_imp&) = default;
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allocator_type get_allocator() const { return _M_alloc; }
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allocator_type get_allocator() const noexcept { return _M_alloc; }
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protected:
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virtual void*
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@ -311,13 +326,13 @@ namespace pmr {
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private:
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// Calculate Aligned Size
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// Returns a size that is larger than or equal to __size and divisible
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// by __alignment, where __alignment is required to be the power of 2.
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// by __alignment, where __alignment is required to be a power of 2.
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static size_t
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_S_aligned_size(size_t __size, size_t __alignment)
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{ return ((__size - 1)|(__alignment - 1)) + 1; }
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// Determine whether alignment meets one of those preconditions:
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// 1. Equals to Zero
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// 1. Equal to Zero
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// 2. Is power of two
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static bool
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_S_supported (size_t __x)
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@ -337,34 +352,33 @@ namespace pmr {
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inline memory_resource*
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new_delete_resource() noexcept
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{
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static resource_adaptor<std::allocator<char>> __r;
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return static_cast<memory_resource*>(&__r);
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using type = resource_adaptor<std::allocator<char>>;
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alignas(type) static unsigned char __buf[sizeof(type)];
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static type* __r = new(__buf) type;
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return __r;
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}
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template <typename _Alloc>
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class __null_memory_resource : private memory_resource
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{
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protected:
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void*
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do_allocate(size_t, size_t)
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{ std::__throw_bad_alloc(); }
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void
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do_deallocate(void*, size_t, size_t) noexcept
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{ }
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bool
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do_is_equal(const memory_resource& __other) const noexcept
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{ return this == &__other; }
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friend memory_resource* null_memory_resource() noexcept;
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};
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inline memory_resource*
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null_memory_resource() noexcept
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{
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static __null_memory_resource<void> __r;
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return static_cast<memory_resource*>(&__r);
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class type final : public memory_resource
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{
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void*
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do_allocate(size_t, size_t) override
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{ std::__throw_bad_alloc(); }
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void
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do_deallocate(void*, size_t, size_t) noexcept override
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{ }
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bool
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do_is_equal(const memory_resource& __other) const noexcept override
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{ return this == &__other; }
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};
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alignas(type) static unsigned char __buf[sizeof(type)];
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static type* __r = new(__buf) type;
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return __r;
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}
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// The default memory resource
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@ -0,0 +1,56 @@
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// Copyright (C) 2018 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// { dg-do run { target c++14 } }
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#include <experimental/memory_resource>
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namespace pmr = std::experimental::pmr;
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struct X
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{
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pmr::memory_resource* res = nullptr;
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void* ptr = nullptr;
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static constexpr std::size_t n = 64;
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constexpr X() { }
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explicit
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X(pmr::memory_resource* r) : res(r), ptr(r->allocate(n)) { }
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~X() { if (ptr) res->deallocate(ptr, n); }
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};
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void
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swap(X& lhs, X& rhs) {
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std::swap(lhs.res, rhs.res);
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std::swap(lhs.ptr, rhs.ptr);
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}
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void
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test01()
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{
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static X x1;
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X x2(pmr::new_delete_resource());
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swap(x1, x2);
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// Now x1 will deallocate the memory during destruction of static objects.
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}
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int main()
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{
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test01();
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}
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