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

   1 // Support routines for the -*- C++ -*- dynamic memory management.
   2
   3 // Copyright (C) 1997-2018 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 <cstdlib>
  28 #include <bits/exception_defines.h>
  29 #include "new"
  30
  31 using std::new_handler;
  32 using std::bad_alloc;
  33 #if _GLIBCXX_HOSTED
  34 using std::malloc;
  35 #else
  36 // A freestanding C runtime may not provide "malloc" -- but there is no
  37 // other reasonable way to implement "operator new".
  38 extern "C" void *malloc (std::size_t);
  39 #endif
  40
  41 _GLIBCXX_WEAK_DEFINITION void *
  42 operator new (std::size_t sz) _GLIBCXX_THROW (std::bad_alloc)
  43 {
  44   void *p;
  45
  46   /* malloc (0) is unpredictable; avoid it.  */
  47   if (sz == 0)
  48     sz = 1;
  49
  50   while (__builtin_expect ((p = malloc (sz)) == 0, false))
  51     {
  52       new_handler handler = std::get_new_handler ();
  53       if (! handler)
  54         _GLIBCXX_THROW_OR_ABORT(bad_alloc());
  55       handler ();
  56     }
  57
  58   return p;
  59 }