gcc/ipa-ref.c

   1 /* Interprocedural reference lists.
   2    Copyright (C) 2010-2015 Free Software Foundation, Inc.
   3    Contributed by Jan Hubicka
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "alias.h"
  25 #include "tree.h"
  26 #include "options.h"
  27 #include "fold-const.h"
  28 #include "target.h"
  29 #include "tm.h"
  30 #include "hard-reg-set.h"
  31 #include "function.h"
  32 #include "cgraph.h"
  33 #include "ipa-utils.h"
  34
  35 /* Remove reference.  */
  36
  37 void
  38 ipa_ref::remove_reference ()
  39 {
  40   struct ipa_ref_list *list = referred_ref_list ();
  41   struct ipa_ref_list *list2 = referring_ref_list ();
  42   vec<ipa_ref_t, va_gc> *old_references = list2->references;
  43   struct ipa_ref *last;
  44
  45   gcc_assert (list->referring[referred_index] == this);
  46
  47   last = list->referring.last ();
  48   if (this != last)
  49     {
  50       if (use == IPA_REF_ALIAS)
  51         {
  52           /* If deleted item is IPA_REF_ALIAS, we have to move last
  53           item of IPA_REF_LIST type to the deleted position. After that
  54           we replace last node with deletion slot.  */
  55           struct ipa_ref *last_alias = list->last_alias ();
  56
  57           if (last_alias && referred_index < last_alias->referred_index
  58               && last_alias != last)
  59           {
  60             unsigned last_alias_index = last_alias->referred_index;
  61
  62             list->referring[referred_index] = last_alias;
  63             list->referring[referred_index]->referred_index = referred_index;
  64
  65             /* New position for replacement is previous index
  66                of the last_alias.  */
  67             referred_index = last_alias_index;
  68           }
  69         }
  70
  71       list->referring[referred_index] = list->referring.last ();
  72       list->referring[referred_index]->referred_index= referred_index;
  73     }
  74   list->referring.pop ();
  75
  76   last = &list2->references->last ();
  77
  78   struct ipa_ref *ref = this;
  79
  80   if (ref != last)
  81     {
  82       *ref = *last;
  83       ref->referred_ref_list ()->referring[referred_index] = ref;
  84     }
  85   list2->references->pop ();
  86   gcc_assert (list2->references == old_references);
  87 }
  88
  89 /* Return true when execution of reference can lead to return from
  90    function.  */
  91
  92 bool
  93 ipa_ref::cannot_lead_to_return ()
  94 {
  95   return dyn_cast <cgraph_node *> (referring)->cannot_return_p ();
  96 }
  97
  98 /* Return reference list this reference is in.  */
  99
 100 struct ipa_ref_list *
 101 ipa_ref::referring_ref_list (void)
 102 {
 103   return &referring->ref_list;
 104 }
 105
 106 /* Return reference list this reference is in.  */
 107
 108 struct ipa_ref_list *
 109 ipa_ref::referred_ref_list (void)
 110 {
 111   return &referred->ref_list;
 112 }