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new-op.cc revision 1.1 
      1 /* Replace operator new/new[], for GDB, the GNU debugger.
      2 
      3    Copyright (C) 2016-2020 Free Software Foundation, Inc.
      4 
      5    This file is part of GDB.
      6 
      7    This program 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 of the License, or
     10    (at your option) any later version.
     11 
     12    This program 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    You should have received a copy of the GNU General Public License
     18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
     19 
     20 /* GCC does not understand __has_feature.  */
     21 #if !defined(__has_feature)
     22 # define __has_feature(x) 0
     23 #endif
     24 
     25 #if !__has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
     26 #include "common-defs.h"
     27 #include "host-defs.h"
     28 #include <new>
     29 
     30 /* Override operator new / operator new[], in order to internal_error
     31    on allocation failure and thus query the user for abort/core
     32    dump/continue, just like xmalloc does.  We don't do this from a
     33    new-handler function instead (std::set_new_handler) because we want
     34    to catch allocation errors from within global constructors too.
     35 
     36    Skip overriding if building with -fsanitize=address though.
     37    Address sanitizer wants to override operator new/delete too in
     38    order to detect malloc+delete and new+free mismatches.  Our
     39    versions would mask out ASan's, with the result of losing that
     40    useful mismatch detection.
     41 
     42    Note that C++ implementations could either have their throw
     43    versions call the nothrow versions (libstdc++), or the other way
     44    around (clang/libc++).  For that reason, we replace both throw and
     45    nothrow variants and call malloc directly.  */
     46 
     47 void *
     48 operator new (std::size_t sz)
     49 {
     50   /* malloc (0) is unpredictable; avoid it.  */
     51   if (sz == 0)
     52     sz = 1;
     53 
     54   void *p = malloc (sz);	/* ARI: malloc */
     55   if (p == NULL)
     56     {
     57       /* If the user decides to continue debugging, throw a
     58 	 gdb_quit_bad_alloc exception instead of a regular QUIT
     59 	 gdb_exception.  The former extends both std::bad_alloc and a
     60 	 QUIT gdb_exception.  This is necessary because operator new
     61 	 can only ever throw std::bad_alloc, or something that extends
     62 	 it.  */
     63       try
     64 	{
     65 	  malloc_failure (sz);
     66 	}
     67       catch (gdb_exception &ex)
     68 	{
     69 	  throw gdb_quit_bad_alloc (std::move (ex));
     70 	}
     71     }
     72   return p;
     73 }
     74 
     75 void *
     76 operator new (std::size_t sz, const std::nothrow_t&) noexcept
     77 {
     78   /* malloc (0) is unpredictable; avoid it.  */
     79   if (sz == 0)
     80     sz = 1;
     81   return malloc (sz);		/* ARI: malloc */
     82 }
     83 
     84 void *
     85 operator new[] (std::size_t sz)
     86 {
     87    return ::operator new (sz);
     88 }
     89 
     90 void*
     91 operator new[] (std::size_t sz, const std::nothrow_t&) noexcept
     92 {
     93   return ::operator new (sz, std::nothrow);
     94 }
     95 #endif
     96