| // Support routines for the -*- C++ -*- dynamic memory management. |
| |
| // Copyright (C) 1997-2022 Free Software Foundation, Inc. |
| // |
| // This file is part of GCC. |
| // |
| // GCC is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| // |
| // GCC is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| // |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| #include <bits/c++config.h> |
| #include <stdlib.h> |
| #include <stdint.h> |
| #include <bit> |
| #include "new" |
| |
| #if !_GLIBCXX_HAVE_ALIGNED_ALLOC && !_GLIBCXX_HAVE__ALIGNED_MALLOC \ |
| && !_GLIBCXX_HAVE_POSIX_MEMALIGN && _GLIBCXX_HAVE_MEMALIGN |
| # if _GLIBCXX_HOSTED && __has_include(<malloc.h>) |
| // Some C libraries declare memalign in <malloc.h> |
| # include <malloc.h> |
| # else |
| extern "C" void *memalign(std::size_t boundary, std::size_t size); |
| # endif |
| #endif |
| |
| using std::new_handler; |
| using std::bad_alloc; |
| |
| #if ! _GLIBCXX_HOSTED |
| using std::size_t; |
| extern "C" |
| { |
| # if _GLIBCXX_HAVE_ALIGNED_ALLOC |
| void *aligned_alloc(size_t alignment, size_t size); |
| # elif _GLIBCXX_HAVE__ALIGNED_MALLOC |
| void *_aligned_malloc(size_t size, size_t alignment); |
| # elif _GLIBCXX_HAVE_POSIX_MEMALIGN |
| void *posix_memalign(void **, size_t alignment, size_t size); |
| # elif _GLIBCXX_HAVE_MEMALIGN |
| void *memalign(size_t alignment, size_t size); |
| # else |
| // A freestanding C runtime may not provide "malloc" -- but there is no |
| // other reasonable way to implement "operator new". |
| void *malloc(size_t); |
| # endif |
| } |
| #endif |
| |
| namespace __gnu_cxx { |
| #if _GLIBCXX_HAVE_ALIGNED_ALLOC |
| using ::aligned_alloc; |
| #elif _GLIBCXX_HAVE__ALIGNED_MALLOC |
| static inline void* |
| aligned_alloc (std::size_t al, std::size_t sz) |
| { return _aligned_malloc(sz, al); } |
| #elif _GLIBCXX_HAVE_POSIX_MEMALIGN |
| static inline void* |
| aligned_alloc (std::size_t al, std::size_t sz) |
| { |
| void *ptr; |
| // posix_memalign has additional requirement, not present on aligned_alloc: |
| // The value of alignment shall be a power of two multiple of sizeof(void *). |
| if (al < sizeof(void*)) |
| al = sizeof(void*); |
| int ret = posix_memalign (&ptr, al, sz); |
| if (ret == 0) |
| return ptr; |
| return nullptr; |
| } |
| #elif _GLIBCXX_HAVE_MEMALIGN |
| static inline void* |
| aligned_alloc (std::size_t al, std::size_t sz) |
| { |
| // Solaris requires al >= sizeof a word and QNX requires >= sizeof(void*) |
| // but they both provide posix_memalign, so will use the definition above. |
| return memalign (al, sz); |
| } |
| #else // !HAVE__ALIGNED_MALLOC && !HAVE_POSIX_MEMALIGN && !HAVE_MEMALIGN |
| // The C library doesn't provide any aligned allocation functions, define one. |
| // This is a modified version of code from gcc/config/i386/gmm_malloc.h |
| static inline void* |
| aligned_alloc (std::size_t al, std::size_t sz) |
| { |
| // We need extra bytes to store the original value returned by malloc. |
| if (al < sizeof(void*)) |
| al = sizeof(void*); |
| void* const malloc_ptr = malloc(sz + al); |
| if (!malloc_ptr) |
| return nullptr; |
| // Align to the requested value, leaving room for the original malloc value. |
| void* const aligned_ptr = (void *) (((uintptr_t) malloc_ptr + al) & -al); |
| |
| // Store the original malloc value where it can be found by operator delete. |
| ((void **) aligned_ptr)[-1] = malloc_ptr; |
| |
| return aligned_ptr; |
| } |
| #endif |
| } // namespace __gnu_cxx |
| |
| _GLIBCXX_WEAK_DEFINITION void * |
| operator new (std::size_t sz, std::align_val_t al) |
| { |
| std::size_t align = (std::size_t)al; |
| |
| /* Alignment must be a power of two. */ |
| /* XXX This should be checked by the compiler (PR 86878). */ |
| if (__builtin_expect (!std::__has_single_bit(align), false)) |
| _GLIBCXX_THROW_OR_ABORT(bad_alloc()); |
| |
| /* malloc (0) is unpredictable; avoid it. */ |
| if (__builtin_expect (sz == 0, false)) |
| sz = 1; |
| |
| #if _GLIBCXX_HAVE_ALIGNED_ALLOC |
| # if defined _AIX || defined __APPLE__ |
| /* AIX 7.2.0.0 aligned_alloc incorrectly has posix_memalign's requirement |
| * that alignment is a multiple of sizeof(void*). |
| * OS X 10.15 has the same requirement. */ |
| if (align < sizeof(void*)) |
| align = sizeof(void*); |
| # endif |
| /* C11: the value of size shall be an integral multiple of alignment. */ |
| sz = (sz + align - 1) & ~(align - 1); |
| #endif |
| |
| void *p; |
| |
| while ((p = __gnu_cxx::aligned_alloc (align, sz)) == nullptr) |
| { |
| new_handler handler = std::get_new_handler (); |
| if (! handler) |
| _GLIBCXX_THROW_OR_ABORT(bad_alloc()); |
| handler (); |
| } |
| |
| return p; |
| } |