2da049a141
This fixes rdar://110330781, which asked for the feature-test macro for std::pmr to take into account the deployment target. It doesn't fix https://llvm.org/PR62212, though, because the availability markup itself must be disabled until some Clang bugs have been fixed. This is pretty vexing, however at least everything should work once those Clang bugs have been fixed. In the meantime, this patch at least adds the required markup (as disabled) and ensures that the feature-test macro for std::pmr is aware of the deployment target requirement. Differential Revision: https://reviews.llvm.org/D135813
124 lines
4.1 KiB
C++
124 lines
4.1 KiB
C++
//===----------------------------------------------------------------------===//
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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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#ifndef _LIBCPP___MEMORY_RESOURCE_MONOTONIC_BUFFER_RESOURCE_H
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#define _LIBCPP___MEMORY_RESOURCE_MONOTONIC_BUFFER_RESOURCE_H
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#include <__availability>
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#include <__config>
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#include <__memory/addressof.h>
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#include <__memory_resource/memory_resource.h>
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#include <cstddef>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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#if _LIBCPP_STD_VER >= 17
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_LIBCPP_BEGIN_NAMESPACE_STD
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namespace pmr {
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// [mem.res.monotonic.buffer]
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class _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI monotonic_buffer_resource : public memory_resource {
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static const size_t __default_buffer_capacity = 1024;
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static const size_t __default_buffer_alignment = 16;
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struct __chunk_footer {
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__chunk_footer* __next_;
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char* __start_;
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char* __cur_;
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size_t __align_;
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_LIBCPP_HIDE_FROM_ABI size_t __allocation_size() {
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return (reinterpret_cast<char*>(this) - __start_) + sizeof(*this);
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}
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void* __try_allocate_from_chunk(size_t, size_t);
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};
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struct __initial_descriptor {
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char* __start_;
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char* __cur_;
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union {
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char* __end_;
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size_t __size_;
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};
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void* __try_allocate_from_chunk(size_t, size_t);
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};
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public:
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_LIBCPP_HIDE_FROM_ABI monotonic_buffer_resource()
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: monotonic_buffer_resource(nullptr, __default_buffer_capacity, get_default_resource()) {}
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_LIBCPP_HIDE_FROM_ABI explicit monotonic_buffer_resource(size_t __initial_size)
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: monotonic_buffer_resource(nullptr, __initial_size, get_default_resource()) {}
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_LIBCPP_HIDE_FROM_ABI monotonic_buffer_resource(void* __buffer, size_t __buffer_size)
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: monotonic_buffer_resource(__buffer, __buffer_size, get_default_resource()) {}
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_LIBCPP_HIDE_FROM_ABI explicit monotonic_buffer_resource(memory_resource* __upstream)
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: monotonic_buffer_resource(nullptr, __default_buffer_capacity, __upstream) {}
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_LIBCPP_HIDE_FROM_ABI monotonic_buffer_resource(size_t __initial_size, memory_resource* __upstream)
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: monotonic_buffer_resource(nullptr, __initial_size, __upstream) {}
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_LIBCPP_HIDE_FROM_ABI monotonic_buffer_resource(void* __buffer, size_t __buffer_size, memory_resource* __upstream)
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: __res_(__upstream) {
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__initial_.__start_ = static_cast<char*>(__buffer);
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if (__buffer != nullptr) {
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__initial_.__cur_ = static_cast<char*>(__buffer) + __buffer_size;
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__initial_.__end_ = static_cast<char*>(__buffer) + __buffer_size;
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} else {
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__initial_.__cur_ = nullptr;
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__initial_.__size_ = __buffer_size;
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}
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__chunks_ = nullptr;
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}
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monotonic_buffer_resource(const monotonic_buffer_resource&) = delete;
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_LIBCPP_HIDE_FROM_ABI_VIRTUAL ~monotonic_buffer_resource() override { release(); }
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monotonic_buffer_resource& operator=(const monotonic_buffer_resource&) = delete;
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_LIBCPP_HIDE_FROM_ABI void release() {
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if (__initial_.__start_ != nullptr)
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__initial_.__cur_ = __initial_.__end_;
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while (__chunks_ != nullptr) {
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__chunk_footer* __next = __chunks_->__next_;
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__res_->deallocate(__chunks_->__start_, __chunks_->__allocation_size(), __chunks_->__align_);
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__chunks_ = __next;
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}
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}
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_LIBCPP_HIDE_FROM_ABI memory_resource* upstream_resource() const { return __res_; }
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protected:
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void* do_allocate(size_t __bytes, size_t __alignment) override; // key function
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_LIBCPP_HIDE_FROM_ABI_VIRTUAL void do_deallocate(void*, size_t, size_t) override {}
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_LIBCPP_HIDE_FROM_ABI_VIRTUAL bool do_is_equal(const memory_resource& __other) const _NOEXCEPT override {
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return this == std::addressof(__other);
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}
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private:
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__initial_descriptor __initial_;
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__chunk_footer* __chunks_;
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memory_resource* __res_;
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};
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} // namespace pmr
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 17
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#endif // _LIBCPP___MEMORY_RESOURCE_MONOTONIC_BUFFER_RESOURCE_H
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