Line data    Source code

       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     2146990 : __libdw_alloc_tail (Dwarf *dbg)
      52             : {
      53     2146990 :   if (thread_id == THREAD_ID_UNSET)
      54         402 :     thread_id = atomic_fetch_add (&next_id, 1);
      55             : 
      56     2146990 :   pthread_rwlock_rdlock (&dbg->mem_rwl);
      57     2146990 :   if (thread_id >= dbg->mem_stacks)
      58             :     {
      59         540 :       pthread_rwlock_unlock (&dbg->mem_rwl);
      60         540 :       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         540 :       if (thread_id >= dbg->mem_stacks)
      66             :         {
      67         540 :           dbg->mem_tails = realloc (dbg->mem_tails, (thread_id+1)
      68             :                                     * sizeof (struct libdw_memblock *));
      69         540 :           if (dbg->mem_tails == NULL)
      70             :             {
      71           0 :               pthread_rwlock_unlock (&dbg->mem_rwl);
      72           0 :               dbg->oom_handler();
      73             :             }
      74        1087 :           for (size_t i = dbg->mem_stacks; i <= thread_id; i++)
      75         547 :             dbg->mem_tails[i] = NULL;
      76         540 :           dbg->mem_stacks = thread_id + 1;
      77         540 :           ANNOTATE_HAPPENS_BEFORE (&dbg->mem_tails);
      78             :         }
      79             : 
      80         540 :       pthread_rwlock_unlock (&dbg->mem_rwl);
      81         540 :       pthread_rwlock_rdlock (&dbg->mem_rwl);
      82             :     }
      83             : 
      84             :   /* At this point, we have an entry in the tail array.  */
      85     2146990 :   ANNOTATE_HAPPENS_AFTER (&dbg->mem_tails);
      86     2146990 :   struct libdw_memblock *result = dbg->mem_tails[thread_id];
      87     2146990 :   if (result == NULL)
      88             :     {
      89         540 :       result = malloc (dbg->mem_default_size);
      90        1080 :       result->size = dbg->mem_default_size
      91         540 :                      - offsetof (struct libdw_memblock, mem);
      92         540 :       result->remaining = result->size;
      93         540 :       result->prev = NULL;
      94         540 :       dbg->mem_tails[thread_id] = result;
      95             :     }
      96     2146990 :   pthread_rwlock_unlock (&dbg->mem_rwl);
      97     2146990 :   return result;
      98             : }
      99             : 
     100             : /* Can only be called after a allocation for this thread has already
     101             :    been done, to possibly undo it.  */
     102             : struct libdw_memblock *
     103           0 : __libdw_thread_tail (Dwarf *dbg)
     104             : {
     105           0 :   struct libdw_memblock *result;
     106           0 :   pthread_rwlock_rdlock (&dbg->mem_rwl);
     107           0 :   result = dbg->mem_tails[thread_id];
     108           0 :   pthread_rwlock_unlock (&dbg->mem_rwl);
     109           0 :   return result;
     110             : }
     111             : 
     112             : void *
     113       18439 : __libdw_allocate (Dwarf *dbg, size_t minsize, size_t align)
     114             : {
     115       18439 :   size_t size = MAX (dbg->mem_default_size,
     116             :                      (align - 1 +
     117             :                       2 * minsize + offsetof (struct libdw_memblock, mem)));
     118       18439 :   struct libdw_memblock *newp = malloc (size);
     119       18439 :   if (newp == NULL)
     120           0 :     dbg->oom_handler ();
     121             : 
     122       18439 :   uintptr_t result = ((uintptr_t) newp->mem + align - 1) & ~(align - 1);
     123             : 
     124       18439 :   newp->size = size - offsetof (struct libdw_memblock, mem);
     125       18439 :   newp->remaining = (uintptr_t) newp + size - (result + minsize);
     126             : 
     127       18439 :   pthread_rwlock_rdlock (&dbg->mem_rwl);
     128       18439 :   newp->prev = dbg->mem_tails[thread_id];
     129       18439 :   dbg->mem_tails[thread_id] = newp;
     130       18439 :   pthread_rwlock_unlock (&dbg->mem_rwl);
     131             : 
     132       18439 :   return (void *) result;
     133             : }
     134             : 
     135             : 
     136             : Dwarf_OOM
     137           0 : dwarf_new_oom_handler (Dwarf *dbg, Dwarf_OOM handler)
     138             : {
     139           0 :   Dwarf_OOM old = dbg->oom_handler;
     140           0 :   dbg->oom_handler = handler;
     141           0 :   return old;
     142             : }
     143             : 
     144             : 
     145             : void
     146             : __attribute ((noreturn)) attribute_hidden
     147           0 : __libdw_oom (void)
     148             : {
     149           0 :   while (1)
     150           0 :     error (EXIT_FAILURE, ENOMEM, "libdw");
     151             : }