149 lines
4.6 KiB
C++
149 lines
4.6 KiB
C++
// Support routines for the -*- C++ -*- dynamic memory management.
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// Copyright (C) 1997-2021 Free Software Foundation, Inc.
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//
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// This file is part of GCC.
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//
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// GCC is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// GCC 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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//
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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#include <bits/c++config.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <bit>
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#include "new"
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#if !_GLIBCXX_HAVE_ALIGNED_ALLOC && !_GLIBCXX_HAVE__ALIGNED_MALLOC \
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&& !_GLIBCXX_HAVE_POSIX_MEMALIGN && _GLIBCXX_HAVE_MEMALIGN
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# if _GLIBCXX_HOSTED && __has_include(<malloc.h>)
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// Some C libraries declare memalign in <malloc.h>
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# include <malloc.h>
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# else
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extern "C" void *memalign(std::size_t boundary, std::size_t size);
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# endif
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#endif
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using std::new_handler;
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using std::bad_alloc;
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#if ! _GLIBCXX_HOSTED
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using std::size_t;
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extern "C"
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{
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# if _GLIBCXX_HAVE_ALIGNED_ALLOC
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void *aligned_alloc(size_t alignment, size_t size);
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# elif _GLIBCXX_HAVE__ALIGNED_MALLOC
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void *_aligned_malloc(size_t size, size_t alignment);
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# elif _GLIBCXX_HAVE_POSIX_MEMALIGN
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void *posix_memalign(void **, size_t alignment, size_t size);
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# elif _GLIBCXX_HAVE_MEMALIGN
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void *memalign(size_t alignment, size_t size);
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# endif
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}
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#endif
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namespace __gnu_cxx {
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#if _GLIBCXX_HAVE_ALIGNED_ALLOC
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using ::aligned_alloc;
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#elif _GLIBCXX_HAVE__ALIGNED_MALLOC
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static inline void*
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aligned_alloc (std::size_t al, std::size_t sz)
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{ return _aligned_malloc(sz, al); }
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#elif _GLIBCXX_HAVE_POSIX_MEMALIGN
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static inline void*
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aligned_alloc (std::size_t al, std::size_t sz)
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{
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void *ptr;
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// posix_memalign has additional requirement, not present on aligned_alloc:
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// The value of alignment shall be a power of two multiple of sizeof(void *).
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if (al < sizeof(void*))
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al = sizeof(void*);
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int ret = posix_memalign (&ptr, al, sz);
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if (ret == 0)
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return ptr;
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return nullptr;
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}
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#elif _GLIBCXX_HAVE_MEMALIGN
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static inline void*
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aligned_alloc (std::size_t al, std::size_t sz)
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{
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return memalign (al, sz);
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}
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#else // !HAVE__ALIGNED_MALLOC && !HAVE_POSIX_MEMALIGN && !HAVE_MEMALIGN
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// The C library doesn't provide any aligned allocation functions, define one.
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// This is a modified version of code from gcc/config/i386/gmm_malloc.h
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static inline void*
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aligned_alloc (std::size_t al, std::size_t sz)
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{
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// We need extra bytes to store the original value returned by malloc.
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if (al < sizeof(void*))
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al = sizeof(void*);
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void* const malloc_ptr = malloc(sz + al);
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if (!malloc_ptr)
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return nullptr;
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// Align to the requested value, leaving room for the original malloc value.
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void* const aligned_ptr = (void *) (((uintptr_t) malloc_ptr + al) & -al);
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// Store the original malloc value where it can be found by operator delete.
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((void **) aligned_ptr)[-1] = malloc_ptr;
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return aligned_ptr;
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}
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#endif
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} // namespace __gnu_cxx
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_GLIBCXX_WEAK_DEFINITION void *
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operator new (std::size_t sz, std::align_val_t al)
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{
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std::size_t align = (std::size_t)al;
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/* Alignment must be a power of two. */
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/* XXX This should be checked by the compiler (PR 86878). */
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if (__builtin_expect (!std::__has_single_bit(align), false))
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_GLIBCXX_THROW_OR_ABORT(bad_alloc());
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/* malloc (0) is unpredictable; avoid it. */
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if (__builtin_expect (sz == 0, false))
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sz = 1;
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#if _GLIBCXX_HAVE_ALIGNED_ALLOC
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# if defined _AIX || defined __APPLE__
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/* AIX 7.2.0.0 aligned_alloc incorrectly has posix_memalign's requirement
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* that alignment is a multiple of sizeof(void*).
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* OS X 10.15 has the same requirement. */
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if (align < sizeof(void*))
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align = sizeof(void*);
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# endif
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/* C11: the value of size shall be an integral multiple of alignment. */
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sz = (sz + align - 1) & ~(align - 1);
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#endif
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void *p;
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while ((p = __gnu_cxx::aligned_alloc (align, sz)) == nullptr)
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{
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new_handler handler = std::get_new_handler ();
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if (! handler)
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_GLIBCXX_THROW_OR_ABORT(bad_alloc());
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handler ();
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}
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return p;
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}
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