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1 : : /* Representation of thunks inside symbol table.
2 : : Copyright (C) 2003-2024 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_SYMTAB_THUNKS_H
22 : : #define GCC_SYMTAB_THUNKS_H
23 : :
24 : : /* This symbol annotation holds information about thunk.
25 : :
26 : : Thunks are basically wrappers around methods which are introduced in case
27 : : of multiple inheritance in order to adjust the value of the "this" pointer
28 : : or of the returned value.
29 : :
30 : : In the case of this-adjusting thunks, each back-end can override the
31 : : can_output_mi_thunk/output_mi_thunk target hooks to generate a minimal thunk
32 : : (with a tail call for instance) directly as assembly. For the default hook
33 : : or for the case where the can_output_mi_thunk hooks return false, the thunk
34 : : is gimplified and lowered using the regular machinery. */
35 : :
36 : : struct GTY(()) thunk_info {
37 : : /* Constructor. */
38 : 35413 : thunk_info ()
39 : 10588 : : fixed_offset (0),
40 : 30119 : virtual_value (0),
41 : 30119 : indirect_offset (0),
42 : 30119 : alias (NULL),
43 : 30119 : this_adjusting (false),
44 : 30119 : virtual_offset_p (false)
45 : : {
46 : : }
47 : : /* Copy constructor. */
48 : 1246 : thunk_info (const thunk_info &t)
49 : 1246 : : fixed_offset (t.fixed_offset),
50 : 1246 : virtual_value (t.virtual_value),
51 : 1246 : indirect_offset (t.indirect_offset),
52 : 1246 : alias (t.alias),
53 : 1246 : this_adjusting (t.this_adjusting),
54 : 1246 : virtual_offset_p (t.virtual_offset_p)
55 : : {
56 : : }
57 : :
58 : : /* Compare for equiality. */
59 : : bool
60 : 23 : operator==(const thunk_info &other) const
61 : : {
62 : 23 : return fixed_offset == other.fixed_offset
63 : 23 : && virtual_value == other.virtual_value
64 : 23 : && indirect_offset == other.indirect_offset
65 : : && this_adjusting == other.this_adjusting
66 : 46 : && virtual_offset_p == other.virtual_offset_p;
67 : : }
68 : : bool
69 : : operator!=(const thunk_info &other) const
70 : : {
71 : : return !(*this == other);
72 : : }
73 : : /* Copy operator. */
74 : : thunk_info &
75 : 12341 : operator=(const thunk_info &other)
76 : : {
77 : 12341 : fixed_offset = other.fixed_offset;
78 : 12341 : virtual_value = other.virtual_value;
79 : 12341 : indirect_offset = other.indirect_offset;
80 : 12341 : alias = other.alias;
81 : 12341 : this_adjusting = other.this_adjusting;
82 : 12341 : virtual_offset_p = other.virtual_offset_p;
83 : 11834 : return *this;
84 : : }
85 : :
86 : : /* Offset used to adjust "this". */
87 : : HOST_WIDE_INT fixed_offset;
88 : :
89 : : /* Offset in the virtual table to get the offset to adjust "this". Valid iff
90 : : VIRTUAL_OFFSET_P is true. */
91 : : HOST_WIDE_INT virtual_value;
92 : :
93 : : /* Offset from "this" to get the offset to adjust "this". Zero means: this
94 : : offset is to be ignored. */
95 : : HOST_WIDE_INT indirect_offset;
96 : :
97 : : /* Thunk target, i.e. the method that this thunk wraps. Depending on the
98 : : TARGET_USE_LOCAL_THUNK_ALIAS_P macro, this may have to be a new alias. */
99 : : tree alias;
100 : :
101 : : /* Nonzero for a "this" adjusting thunk and zero for a result adjusting
102 : : thunk. */
103 : : bool this_adjusting;
104 : :
105 : : /* If true, this thunk is what we call a virtual thunk. In this case:
106 : : * for this-adjusting thunks, after the FIXED_OFFSET based adjustment is
107 : : done, add to the result the offset found in the vtable at:
108 : : vptr + VIRTUAL_VALUE
109 : : * for result-adjusting thunks, the FIXED_OFFSET adjustment is done after
110 : : the virtual one. */
111 : : bool virtual_offset_p;
112 : :
113 : :
114 : :
115 : : /* Dump thunk_info. */
116 : : void dump (FILE *);
117 : :
118 : : /* Stream out thunk_info. */
119 : : void stream_out (class lto_simple_output_block *);
120 : :
121 : : /* Stream in trunk_info. */
122 : : void stream_in (class lto_input_block *);
123 : :
124 : : hashval_t hash ();
125 : :
126 : :
127 : :
128 : : /* Return thunk_info, if available. */
129 : : static thunk_info *get (cgraph_node *node);
130 : :
131 : : /* Return thunk_info possibly creating new one. */
132 : : static thunk_info *get_create (cgraph_node *node);
133 : :
134 : : /* Remove thunk_info. */
135 : : static void remove (cgraph_node *node);
136 : :
137 : : /* Add unprocessed thunk. */
138 : : void register_early (cgraph_node *node);
139 : :
140 : : /* Attach recorded thunks to cgraph_nodes. */
141 : : static void process_early_thunks ();
142 : :
143 : : /* Release all thunk_infos. */
144 : : static void release (void);
145 : : };
146 : :
147 : : bool expand_thunk (cgraph_node *, bool, bool);
148 : :
149 : : /* Return thunk_info, if available. */
150 : : inline thunk_info *
151 : 3683270 : thunk_info::get (cgraph_node *node)
152 : : {
153 : 3683270 : if (!symtab->m_thunks)
154 : : return NULL;
155 : 93391 : return symtab->m_thunks->get (node);
156 : : }
157 : :
158 : : /* Remove thunk_info association for NODE. */
159 : : inline void
160 : 17635 : thunk_info::remove (cgraph_node *node)
161 : : {
162 : 17635 : symtab->m_thunks->remove (node);
163 : : }
164 : :
165 : : /* Free thunk info summaries. */
166 : : inline void
167 : 253805 : thunk_info::release ()
168 : : {
169 : 253805 : if (symtab->m_thunks)
170 : 5963 : ggc_delete (symtab->m_thunks);
171 : 253805 : symtab->m_thunks = NULL;
172 : 253805 : }
173 : : #endif /* GCC_SYMTAB_THUNKS_H */
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