libitm/alloc.cc

   1 /* Copyright (C) 2009, 2011 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <rth@redhat.com>.
   3
   4    This file is part of the GNU Transactional Memory Library (libitm).
   5
   6    Libitm is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
  12    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14    more details.
  15
  16    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 #include "libitm_i.h"
  26
  27 namespace GTM HIDDEN {
  28
  29 void
  30 gtm_thread::record_allocation (void *ptr, void (*free_fn)(void *))
  31 {
  32   uintptr_t iptr = (uintptr_t) ptr;
  33
  34   gtm_alloc_action *a = this->alloc_actions.find(iptr);
  35   if (a == 0)
  36     a = this->alloc_actions.insert(iptr);
  37
  38   a->free_fn = free_fn;
  39   a->allocated = true;
  40 }
  41
  42 void
  43 gtm_thread::forget_allocation (void *ptr, void (*free_fn)(void *))
  44 {
  45   uintptr_t iptr = (uintptr_t) ptr;
  46
  47   gtm_alloc_action *a = this->alloc_actions.find(iptr);
  48   if (a == 0)
  49     a = this->alloc_actions.insert(iptr);
  50
  51   a->free_fn = free_fn;
  52   a->allocated = false;
  53 }
  54
  55 namespace {
  56 struct commit_cb_data {
  57   aa_tree<uintptr_t, gtm_alloc_action>* parent;
  58   bool revert_p;
  59 };
  60 }
  61
  62 static void
  63 commit_allocations_2 (uintptr_t key, gtm_alloc_action *a, void *data)
  64 {
  65   void *ptr = (void *)key;
  66   commit_cb_data *cb_data = static_cast<commit_cb_data *>(data);
  67
  68   if (cb_data->revert_p)
  69     {
  70       // Roll back nested allocations.
  71       if (a->allocated)
  72         a->free_fn (ptr);
  73     }
  74   else
  75     {
  76       if (a->allocated)
  77         {
  78           // Add nested allocations to parent transaction.
  79           gtm_alloc_action* a_parent = cb_data->parent->insert(key);
  80           *a_parent = *a;
  81         }
  82       else
  83         {
  84           // ??? We could eliminate a parent allocation that matches this
  85           // memory release, if we had support for removing all accesses
  86           // to this allocation from the transaction's undo and redo logs
  87           // (otherwise, the parent transaction's undo or redo might write to
  88           // data that is already shared again because of calling free()).
  89           // We don't have this support currently, and the benefit of this
  90           // optimization is unknown, so just add it to the parent.
  91           gtm_alloc_action* a_parent;
  92           a_parent = cb_data->parent->insert(key);
  93           *a_parent = *a;
  94         }
  95     }
  96 }
  97
  98 static void
  99 commit_allocations_1 (uintptr_t key, gtm_alloc_action *a, void *cb_data)
 100 {
 101   void *ptr = (void *)key;
 102   uintptr_t revert_p = (uintptr_t) cb_data;
 103
 104   if (a->allocated == revert_p)
 105     a->free_fn (ptr);
 106 }
 107
 108 /* Permanently commit allocated memory during transaction.
 109
 110    REVERT_P is true if instead of committing the allocations, we want
 111    to roll them back (and vice versa).  */
 112 void
 113 gtm_thread::commit_allocations (bool revert_p,
 114     aa_tree<uintptr_t, gtm_alloc_action>* parent)
 115 {
 116   if (parent)
 117     {
 118       commit_cb_data cb_data;
 119       cb_data.parent = parent;
 120       cb_data.revert_p = revert_p;
 121       this->alloc_actions.traverse (commit_allocations_2, &cb_data);
 122     }
 123   else
 124     this->alloc_actions.traverse (commit_allocations_1,
 125                                   (void *)(uintptr_t)revert_p);
 126   this->alloc_actions.clear ();
 127 }
 128
 129 } // namespace GTM