This reapplies upstream commit fd484be, as there is a follow-up fix for
the possible hangs in __cxa_guard_acquire() on i386:
Atomics cleanup (#11)
We need to test exception specifiers but they're gone in C++17 so
compile the tests with an older version of the standard.
Rewrite the guard logic to be more idiomatic C++ and more
comprehensible and make sure that atomics are used where necessary.
Obtained from: https://github.com/libcxxrt/libcxxrt/commit/fd484be
Fixes: 56aaed388b
MFC after: 2 weeks
192 lines
4.2 KiB
C++
192 lines
4.2 KiB
C++
/*
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* Copyright 2010-2011 PathScale, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
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* IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* memory.cc - Contains stub definition of C++ new/delete operators.
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*
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* These definitions are intended to be used for testing and are weak symbols
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* to allow them to be replaced by definitions from a STL implementation.
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* These versions simply wrap malloc() and free(), they do not provide a
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* C++-specific allocator.
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*/
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#include <stddef.h>
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#include <stdlib.h>
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#include "stdexcept.h"
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#include "atomic.h"
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namespace std
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{
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struct nothrow_t {};
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}
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/// The type of the function called when allocation fails.
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typedef void (*new_handler)();
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/**
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* The function to call when allocation fails. By default, there is no
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* handler and a bad allocation exception is thrown if an allocation fails.
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*/
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static atomic<new_handler> new_handl{nullptr};
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namespace std
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{
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/**
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* Sets a function to be called when there is a failure in new.
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*/
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__attribute__((weak))
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new_handler set_new_handler(new_handler handler)
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{
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return new_handl.exchange(handler);
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}
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__attribute__((weak))
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new_handler get_new_handler(void)
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{
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return new_handl.load();
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}
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}
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#if __cplusplus < 201103L
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#define NOEXCEPT throw()
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#define BADALLOC throw(std::bad_alloc)
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#else
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#define NOEXCEPT noexcept
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#define BADALLOC
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#endif
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namespace
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{
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/**
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* Helper for forwarding from no-throw operators to versions that can
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* return nullptr. Catches any exception and converts it into a nullptr
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* return.
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*/
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template<void*(New)(size_t)>
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void *noexcept_new(size_t size)
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{
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#if !defined(_CXXRT_NO_EXCEPTIONS)
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try
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{
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return New(size);
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} catch (...)
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{
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// nothrow operator new should return NULL in case of
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// std::bad_alloc exception in new handler
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return nullptr;
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}
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#else
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return New(size);
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#endif
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}
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}
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__attribute__((weak))
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void* operator new(size_t size) BADALLOC
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{
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if (0 == size)
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{
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size = 1;
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}
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void * mem = malloc(size);
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while (0 == mem)
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{
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new_handler h = std::get_new_handler();
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if (0 != h)
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{
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h();
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}
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else
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{
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#if !defined(_CXXRT_NO_EXCEPTIONS)
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throw std::bad_alloc();
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#else
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break;
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#endif
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}
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mem = malloc(size);
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}
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return mem;
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}
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__attribute__((weak))
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void* operator new(size_t size, const std::nothrow_t &) NOEXCEPT
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{
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return noexcept_new<(::operator new)>(size);
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}
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__attribute__((weak))
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void operator delete(void * ptr) NOEXCEPT
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{
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free(ptr);
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}
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__attribute__((weak))
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void * operator new[](size_t size) BADALLOC
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{
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return ::operator new(size);
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}
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__attribute__((weak))
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void * operator new[](size_t size, const std::nothrow_t &) NOEXCEPT
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{
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return noexcept_new<(::operator new[])>(size);
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}
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__attribute__((weak))
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void operator delete[](void * ptr) NOEXCEPT
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{
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::operator delete(ptr);
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}
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// C++14 additional delete operators
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#if __cplusplus >= 201402L
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__attribute__((weak))
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void operator delete(void * ptr, size_t) NOEXCEPT
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{
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::operator delete(ptr);
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}
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__attribute__((weak))
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void operator delete[](void * ptr, size_t) NOEXCEPT
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{
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::operator delete(ptr);
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}
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#endif
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