libstdc++-v3/libsupc++/new_opa.cc

   1 // Support routines for the -*- C++ -*- dynamic memory management.
   2
   3 // Copyright (C) 1997-2016 Free Software Foundation, Inc.
   4 //
   5 // This file is part of GCC.
   6 //
   7 // GCC is free software; you can redistribute it and/or modify
   8 // it under the terms of the GNU General Public License as published by
   9 // the Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11 //
  12 // GCC is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 #include <bits/c++config.h>
  27 #include <stdlib.h>
  28 #include <bits/exception_defines.h>
  29 #include "new"
  30
  31 using std::new_handler;
  32 using std::bad_alloc;
  33
  34 #if !_GLIBCXX_HAVE_ALIGNED_ALLOC
  35 #if _GLIBCXX_HAVE__ALIGNED_MALLOC
  36 #define aligned_alloc(al,sz) _aligned_malloc(sz,al)
  37 #elif _GLIBCXX_HAVE_POSIX_MEMALIGN
  38 static inline void*
  39 aligned_alloc (std::size_t al, std::size_t sz)
  40 {
  41   void *ptr;
  42   // The value of alignment shall be a power of two multiple of sizeof(void *).
  43   if (al < sizeof(void*))
  44     al = sizeof(void*);
  45   int ret = posix_memalign (&ptr, al, sz);
  46   if (ret == 0)
  47     return ptr;
  48   return nullptr;
  49 }
  50 #elif _GLIBCXX_HAVE_MEMALIGN
  51 #if _GLIBCXX_HOSTED
  52 #include <malloc.h>
  53 #else
  54 extern "C" void *memalign(std::size_t boundary, std::size_t size);
  55 #endif
  56 #define aligned_alloc memalign
  57 #else
  58 // The C library doesn't provide any aligned allocation functions, declare
  59 // aligned_alloc and get a link failure if aligned new is used.
  60 extern "C" void *aligned_alloc(std::size_t, std::size_t);
  61 #endif
  62 #endif
  63
  64 _GLIBCXX_WEAK_DEFINITION void *
  65 operator new (std::size_t sz, std::align_val_t al)
  66 {
  67   void *p;
  68   std::size_t align = (std::size_t)al;
  69
  70   /* malloc (0) is unpredictable; avoid it.  */
  71   if (sz == 0)
  72     sz = 1;
  73
  74 #if _GLIBCXX_HAVE_ALIGNED_ALLOC
  75   /* C11: the value of size shall be an integral multiple of alignment.  */
  76   if (std::size_t rem = sz & (align - 1))
  77     sz += align - rem;
  78 #endif
  79
  80   while (__builtin_expect ((p = aligned_alloc (align, sz)) == 0, false))
  81     {
  82       new_handler handler = std::get_new_handler ();
  83       if (! handler)
  84         _GLIBCXX_THROW_OR_ABORT(bad_alloc());
  85       handler ();
  86     }
  87
  88   return p;
  89 }