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 "symtab.h"
  26 #include "options.h"
  27 #include "tree.h"
  28 #include "fold-const.h"
  29 #include "target.h"
  30 #include "tm.h"
  31 #include "hard-reg-set.h"
  32 #include "function.h"
  33 #include "cgraph.h"
  34 #include "ipa-utils.h"
  35
  36 /* Remove reference.  */
  37
  38 void
  39 ipa_ref::remove_reference ()
  40 {
  41   struct ipa_ref_list *list = referred_ref_list ();
  42   struct ipa_ref_list *list2 = referring_ref_list ();
  43   vec<ipa_ref_t, va_gc> *old_references = list2->references;
  44   struct ipa_ref *last;
  45
  46   gcc_assert (list->referring[referred_index] == this);
  47
  48   last = list->referring.last ();
  49   if (this != last)
  50     {
  51       if (use == IPA_REF_ALIAS)
  52         {
  53           /* If deleted item is IPA_REF_ALIAS, we have to move last
  54           item of IPA_REF_LIST type to the deleted position. After that
  55           we replace last node with deletion slot.  */
  56           struct ipa_ref *last_alias = list->last_alias ();
  57
  58           if (last_alias && referred_index < last_alias->referred_index
  59               && last_alias != last)
  60           {
  61             unsigned last_alias_index = last_alias->referred_index;
  62
  63             list->referring[referred_index] = last_alias;
  64             list->referring[referred_index]->referred_index = referred_index;
  65
  66             /* New position for replacement is previous index
  67                of the last_alias.  */
  68             referred_index = last_alias_index;
  69           }
  70         }
  71
  72       list->referring[referred_index] = list->referring.last ();
  73       list->referring[referred_index]->referred_index= referred_index;
  74     }
  75   list->referring.pop ();
  76
  77   last = &list2->references->last ();
  78
  79   struct ipa_ref *ref = this;
  80
  81   if (ref != last)
  82     {
  83       *ref = *last;
  84       ref->referred_ref_list ()->referring[referred_index] = ref;
  85     }
  86   list2->references->pop ();
  87   gcc_assert (list2->references == old_references);
  88 }
  89
  90 /* Return true when execution of reference can lead to return from
  91    function.  */
  92
  93 bool
  94 ipa_ref::cannot_lead_to_return ()
  95 {
  96   return dyn_cast <cgraph_node *> (referring)->cannot_return_p ();
  97 }
  98
  99 /* Return reference list this reference is in.  */
 100
 101 struct ipa_ref_list *
 102 ipa_ref::referring_ref_list (void)
 103 {
 104   return &referring->ref_list;
 105 }
 106
 107 /* Return reference list this reference is in.  */
 108
 109 struct ipa_ref_list *
 110 ipa_ref::referred_ref_list (void)
 111 {
 112   return &referred->ref_list;
 113 }