1 /* Interprocedural reference lists.
2    Copyright (C) 2010-2020 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 "target.h"
25 #include "tree.h"
26 #include "cgraph.h"
27 
28 /* Remove reference.  */
29 
30 void
remove_reference()31 ipa_ref::remove_reference ()
32 {
33   struct ipa_ref_list *list = referred_ref_list ();
34   struct ipa_ref_list *list2 = referring_ref_list ();
35   vec<ipa_ref_t, va_gc> *old_references = list2->references;
36   struct ipa_ref *last;
37 
38   gcc_assert (list->referring[referred_index] == this);
39 
40   last = list->referring.last ();
41   if (this != last)
42     {
43       if (use == IPA_REF_ALIAS)
44         {
45 	  /* If deleted item is IPA_REF_ALIAS, we have to move last
46 	  item of IPA_REF_LIST type to the deleted position. After that
47 	  we replace last node with deletion slot.  */
48 	  struct ipa_ref *last_alias = list->last_alias ();
49 
50 	  if (last_alias && referred_index < last_alias->referred_index
51 	      && last_alias != last)
52 	  {
53 	    unsigned last_alias_index = last_alias->referred_index;
54 
55 	    list->referring[referred_index] = last_alias;
56 	    list->referring[referred_index]->referred_index = referred_index;
57 
58 	    /* New position for replacement is previous index
59 	       of the last_alias.  */
60 	    referred_index = last_alias_index;
61 	  }
62 	}
63 
64       list->referring[referred_index] = list->referring.last ();
65       list->referring[referred_index]->referred_index= referred_index;
66     }
67   list->referring.pop ();
68 
69   last = &list2->references->last ();
70 
71   struct ipa_ref *ref = this;
72 
73   if (ref != last)
74     {
75       *ref = *last;
76       ref->referred_ref_list ()->referring[referred_index] = ref;
77     }
78   list2->references->pop ();
79   gcc_assert (list2->references == old_references);
80 }
81 
82 /* Return true when execution of reference can lead to return from
83    function.  */
84 
85 bool
cannot_lead_to_return()86 ipa_ref::cannot_lead_to_return ()
87 {
88   return dyn_cast <cgraph_node *> (referring)->cannot_return_p ();
89 }
90 
91 /* Return reference list this reference is in.  */
92 
93 struct ipa_ref_list *
referring_ref_list(void)94 ipa_ref::referring_ref_list (void)
95 {
96   return &referring->ref_list;
97 }
98 
99 /* Return reference list this reference is in.  */
100 
101 struct ipa_ref_list *
referred_ref_list(void)102 ipa_ref::referred_ref_list (void)
103 {
104   return &referred->ref_list;
105 }
106