1 /* IPA 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 #ifndef GCC_IPA_REF_H
22 #define GCC_IPA_REF_H
23 
24 struct cgraph_node;
25 struct varpool_node;
26 struct 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 };
37 
38 /* Record of reference in callgraph or varpool.  */
39 struct GTY(()) ipa_ref
40 {
41 public:
42   /* Remove reference.  */
43   void remove_reference ();
44 
45   /* Return true when execution of reference can lead to return from
46      function.  */
47   bool cannot_lead_to_return ();
48 
49   /* Return true if reference may be used in address compare.  */
50   bool address_matters_p ();
51 
52   /* Return reference list this reference is in.  */
53   struct ipa_ref_list * referring_ref_list (void);
54 
55   /* Return reference list this reference is in.  */
56   struct ipa_ref_list * referred_ref_list (void);
57 
58   symtab_node *referring;
59   symtab_node *referred;
60   gimple *stmt;
61   unsigned int lto_stmt_uid;
62   /* speculative id is used to link direct calls with their corresponding
63      IPA_REF_ADDR references when representing speculative calls.  */
64   unsigned int speculative_id : 16;
65   unsigned int referred_index;
66   ENUM_BITFIELD (ipa_ref_use) use:3;
67   unsigned int speculative:1;
68 };
69 
70 typedef struct ipa_ref ipa_ref_t;
71 typedef struct ipa_ref *ipa_ref_ptr;
72 
73 
74 /* List of references.  This is stored in both callgraph and varpool nodes.  */
75 struct GTY(()) ipa_ref_list
76 {
77 public:
78   /* Return first reference in list or NULL if empty.  */
first_referenceipa_ref_list79   struct ipa_ref *first_reference (void)
80   {
81     if (!vec_safe_length (references))
82       return NULL;
83     return &(*references)[0];
84   }
85 
86   /* Return first referring ref in list or NULL if empty.  */
first_referringipa_ref_list87   struct ipa_ref *first_referring (void)
88   {
89     if (!referring.length ())
90       return NULL;
91     return referring[0];
92   }
93 
94   /* Return first referring alias.  */
first_aliasipa_ref_list95   struct ipa_ref *first_alias (void)
96   {
97     struct ipa_ref *r = first_referring ();
98 
99     return r && r->use == IPA_REF_ALIAS ? r : NULL;
100   }
101 
102   /* Return last referring alias.  */
last_aliasipa_ref_list103   struct ipa_ref *last_alias (void)
104   {
105     unsigned int i = 0;
106 
107     for(i = 0; i < referring.length (); i++)
108       if (referring[i]->use != IPA_REF_ALIAS)
109 	break;
110 
111     return i == 0 ? NULL : referring[i - 1];
112   }
113 
114   /* Return true if the symbol has an alias.  */
has_aliases_pipa_ref_list115   bool inline has_aliases_p (void)
116   {
117     return first_alias ();
118   }
119 
120   /* Clear reference list.  */
clearipa_ref_list121   void clear (void)
122   {
123     referring.create (0);
124     references = NULL;
125   }
126 
127   /* Return number of references.  */
nreferencesipa_ref_list128   unsigned int nreferences (void)
129   {
130     return vec_safe_length (references);
131   }
132 
133   /* Store actual references in references vector.  */
134   vec<ipa_ref_t, va_gc> *references;
135   /* Referring is vector of pointers to references.  It must not live in GGC space
136      or GGC will try to mark middle of references vectors.  */
137   vec<ipa_ref_ptr>  GTY((skip)) referring;
138 };
139 
140 #endif /* GCC_IPA_REF_H */
141