1 /* IPA reference lists.
2    Copyright (C) 2010-2018 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 #ifndef GCC_IPA_REF_H
22 #define GCC_IPA_REF_H
23 
24 struct cgraph_node;
25 class varpool_node;
26 class symtab_node;
27 
28 
29 /* How the reference is done.  */
30 enum GTY(()) ipa_ref_use
31 {
32   IPA_REF_LOAD,
33   IPA_REF_STORE,
34   IPA_REF_ADDR,
35   IPA_REF_ALIAS,
36   IPA_REF_CHKP
37 };
38 
39 /* Record of reference in callgraph or varpool.  */
40 struct GTY(()) ipa_ref
41 {
42 public:
43   /* Remove reference.  */
44   void remove_reference ();
45 
46   /* Return true when execution of reference can lead to return from
47      function.  */
48   bool cannot_lead_to_return ();
49 
50   /* Return true if refernece may be used in address compare.  */
51   bool address_matters_p ();
52 
53   /* Return reference list this reference is in.  */
54   struct ipa_ref_list * referring_ref_list (void);
55 
56   /* Return reference list this reference is in.  */
57   struct ipa_ref_list * referred_ref_list (void);
58 
59   symtab_node *referring;
60   symtab_node *referred;
61   gimple *stmt;
62   unsigned int lto_stmt_uid;
63   unsigned int referred_index;
64   ENUM_BITFIELD (ipa_ref_use) use:3;
65   unsigned int speculative:1;
66 };
67 
68 typedef struct ipa_ref ipa_ref_t;
69 typedef struct ipa_ref *ipa_ref_ptr;
70 
71 
72 /* List of references.  This is stored in both callgraph and varpool nodes.  */
73 struct GTY(()) ipa_ref_list
74 {
75 public:
76   /* Return first reference in list or NULL if empty.  */
first_referenceipa_ref_list77   struct ipa_ref *first_reference (void)
78   {
79     if (!vec_safe_length (references))
80       return NULL;
81     return &(*references)[0];
82   }
83 
84   /* Return first referring ref in list or NULL if empty.  */
first_referringipa_ref_list85   struct ipa_ref *first_referring (void)
86   {
87     if (!referring.length ())
88       return NULL;
89     return referring[0];
90   }
91 
92   /* Return first referring alias.  */
first_aliasipa_ref_list93   struct ipa_ref *first_alias (void)
94   {
95     struct ipa_ref *r = first_referring ();
96 
97     return r && r->use == IPA_REF_ALIAS ? r : NULL;
98   }
99 
100   /* Return last referring alias.  */
last_aliasipa_ref_list101   struct ipa_ref *last_alias (void)
102   {
103     unsigned int i = 0;
104 
105     for(i = 0; i < referring.length (); i++)
106       if (referring[i]->use != IPA_REF_ALIAS)
107 	break;
108 
109     return i == 0 ? NULL : referring[i - 1];
110   }
111 
112   /* Return true if the symbol has an alias.  */
has_aliases_pipa_ref_list113   bool inline has_aliases_p (void)
114   {
115     return first_alias ();
116   }
117 
118   /* Clear reference list.  */
clearipa_ref_list119   void clear (void)
120   {
121     referring.create (0);
122     references = NULL;
123   }
124 
125   /* Return number of references.  */
nreferencesipa_ref_list126   unsigned int nreferences (void)
127   {
128     return vec_safe_length (references);
129   }
130 
131   /* Store actual references in references vector.  */
132   vec<ipa_ref_t, va_gc> *references;
133   /* Referring is vector of pointers to references.  It must not live in GGC space
134      or GGC will try to mark middle of references vectors.  */
135   vec<ipa_ref_ptr>  GTY((skip)) referring;
136 };
137 
138 #endif /* GCC_IPA_REF_H */
139