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       1                 :            : /* Memory handling for libdw.
       2                 :            :    Copyright (C) 2003, 2004, 2006 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Written by Ulrich Drepper <drepper@redhat.com>, 2003.
       5                 :            : 
       6                 :            :    This file is free software; you can redistribute it and/or modify
       7                 :            :    it under the terms of either
       8                 :            : 
       9                 :            :      * the GNU Lesser General Public License as published by the Free
      10                 :            :        Software Foundation; either version 3 of the License, or (at
      11                 :            :        your option) any later version
      12                 :            : 
      13                 :            :    or
      14                 :            : 
      15                 :            :      * the GNU General Public License as published by the Free
      16                 :            :        Software Foundation; either version 2 of the License, or (at
      17                 :            :        your option) any later version
      18                 :            : 
      19                 :            :    or both in parallel, as here.
      20                 :            : 
      21                 :            :    elfutils is distributed in the hope that it will be useful, but
      22                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      23                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      24                 :            :    General Public License for more details.
      25                 :            : 
      26                 :            :    You should have received copies of the GNU General Public License and
      27                 :            :    the GNU Lesser General Public License along with this program.  If
      28                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      29                 :            : 
      30                 :            : #ifdef HAVE_CONFIG_H
      31                 :            : # include <config.h>
      32                 :            : #endif
      33                 :            : 
      34                 :            : #include <errno.h>
      35                 :            : #include <stdlib.h>
      36                 :            : #include "libdwP.h"
      37                 :            : #include "system.h"
      38                 :            : #include "atomics.h"
      39                 :            : #if USE_VG_ANNOTATIONS == 1
      40                 :            : #include <helgrind.h>
      41                 :            : #else
      42                 :            : #define ANNOTATE_HAPPENS_BEFORE(X)
      43                 :            : #define ANNOTATE_HAPPENS_AFTER(X)
      44                 :            : #endif
      45                 :            : 
      46                 :            : #define THREAD_ID_UNSET ((size_t) -1)
      47                 :            : static __thread size_t thread_id = THREAD_ID_UNSET;
      48                 :            : static atomic_size_t next_id = ATOMIC_VAR_INIT(0);
      49                 :            : 
      50                 :            : struct libdw_memblock *
      51                 :    5926292 : __libdw_alloc_tail (Dwarf *dbg)
      52                 :            : {
      53         [ +  + ]:    5926292 :   if (thread_id == THREAD_ID_UNSET)
      54                 :       1148 :     thread_id = atomic_fetch_add (&next_id, 1);
      55                 :            : 
      56                 :    5926292 :   pthread_rwlock_rdlock (&dbg->mem_rwl);
      57         [ +  + ]:    5926292 :   if (thread_id >= dbg->mem_stacks)
      58                 :            :     {
      59                 :       1626 :       pthread_rwlock_unlock (&dbg->mem_rwl);
      60                 :       1626 :       pthread_rwlock_wrlock (&dbg->mem_rwl);
      61                 :            : 
      62                 :            :       /* Another thread may have already reallocated. In theory using an
      63                 :            :          atomic would be faster, but given that this only happens once per
      64                 :            :          thread per Dwarf, some minor slowdown should be fine.  */
      65         [ +  - ]:       1626 :       if (thread_id >= dbg->mem_stacks)
      66                 :            :         {
      67                 :       1626 :           dbg->mem_tails = realloc (dbg->mem_tails, (thread_id+1)
      68                 :            :                                     * sizeof (struct libdw_memblock *));
      69         [ -  + ]:       1626 :           if (dbg->mem_tails == NULL)
      70                 :            :             {
      71                 :          0 :               pthread_rwlock_unlock (&dbg->mem_rwl);
      72                 :          0 :               dbg->oom_handler();
      73                 :            :             }
      74         [ +  + ]:       3501 :           for (size_t i = dbg->mem_stacks; i <= thread_id; i++)
      75                 :       1875 :             dbg->mem_tails[i] = NULL;
      76                 :       1626 :           dbg->mem_stacks = thread_id + 1;
      77                 :       1626 :           ANNOTATE_HAPPENS_BEFORE (&dbg->mem_tails);
      78                 :            :         }
      79                 :            : 
      80                 :       1626 :       pthread_rwlock_unlock (&dbg->mem_rwl);
      81                 :       1626 :       pthread_rwlock_rdlock (&dbg->mem_rwl);
      82                 :            :     }
      83                 :            : 
      84                 :            :   /* At this point, we have an entry in the tail array.  */
      85                 :    5926292 :   ANNOTATE_HAPPENS_AFTER (&dbg->mem_tails);
      86                 :    5926292 :   struct libdw_memblock *result = dbg->mem_tails[thread_id];
      87         [ +  + ]:    5926292 :   if (result == NULL)
      88                 :            :     {
      89                 :       1626 :       result = malloc (dbg->mem_default_size);
      90         [ -  + ]:       1626 :       if (result == NULL)
      91                 :            :         {
      92                 :          0 :           pthread_rwlock_unlock (&dbg->mem_rwl);
      93                 :          0 :           dbg->oom_handler();
      94                 :            :         }
      95                 :       1626 :       result->size = dbg->mem_default_size
      96                 :       1626 :                      - offsetof (struct libdw_memblock, mem);
      97                 :       1626 :       result->remaining = result->size;
      98                 :       1626 :       result->prev = NULL;
      99                 :       1626 :       dbg->mem_tails[thread_id] = result;
     100                 :            :     }
     101                 :    5926292 :   pthread_rwlock_unlock (&dbg->mem_rwl);
     102                 :    5926292 :   return result;
     103                 :            : }
     104                 :            : 
     105                 :            : /* Can only be called after a allocation for this thread has already
     106                 :            :    been done, to possibly undo it.  */
     107                 :            : struct libdw_memblock *
     108                 :          0 : __libdw_thread_tail (Dwarf *dbg)
     109                 :            : {
     110                 :          0 :   struct libdw_memblock *result;
     111                 :          0 :   pthread_rwlock_rdlock (&dbg->mem_rwl);
     112                 :          0 :   result = dbg->mem_tails[thread_id];
     113                 :          0 :   pthread_rwlock_unlock (&dbg->mem_rwl);
     114                 :          0 :   return result;
     115                 :            : }
     116                 :            : 
     117                 :            : void *
     118                 :      54956 : __libdw_allocate (Dwarf *dbg, size_t minsize, size_t align)
     119                 :            : {
     120                 :      54956 :   size_t size = MAX (dbg->mem_default_size,
     121                 :            :                      (align - 1 +
     122                 :            :                       2 * minsize + offsetof (struct libdw_memblock, mem)));
     123                 :      54956 :   struct libdw_memblock *newp = malloc (size);
     124         [ -  + ]:      54956 :   if (newp == NULL)
     125                 :          0 :     dbg->oom_handler ();
     126                 :            : 
     127                 :      54956 :   uintptr_t result = ((uintptr_t) newp->mem + align - 1) & ~(align - 1);
     128                 :            : 
     129                 :      54956 :   newp->size = size - offsetof (struct libdw_memblock, mem);
     130                 :      54956 :   newp->remaining = (uintptr_t) newp + size - (result + minsize);
     131                 :            : 
     132                 :      54956 :   pthread_rwlock_rdlock (&dbg->mem_rwl);
     133                 :      54956 :   newp->prev = dbg->mem_tails[thread_id];
     134                 :      54956 :   dbg->mem_tails[thread_id] = newp;
     135                 :      54956 :   pthread_rwlock_unlock (&dbg->mem_rwl);
     136                 :            : 
     137                 :      54956 :   return (void *) result;
     138                 :            : }
     139                 :            : 
     140                 :            : 
     141                 :            : Dwarf_OOM
     142                 :          0 : dwarf_new_oom_handler (Dwarf *dbg, Dwarf_OOM handler)
     143                 :            : {
     144                 :          0 :   Dwarf_OOM old = dbg->oom_handler;
     145                 :          0 :   dbg->oom_handler = handler;
     146                 :          0 :   return old;
     147                 :            : }
     148                 :            : 
     149                 :            : 
     150                 :            : void
     151                 :            : __attribute ((noreturn)) attribute_hidden
     152                 :          0 : __libdw_oom (void)
     153                 :            : {
     154                 :          0 :   while (1)
     155                 :          0 :     error (EXIT_FAILURE, ENOMEM, "libdw");
     156                 :            : }