1 /* Control flow graph manipulation code header file.
2 Copyright (C) 2014-2023 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #ifndef GCC_CFG_H
21 #define GCC_CFG_H
22
23 #include "dominance.h"
24
25 /* What sort of profiling information we have. */
26 enum profile_status_d
27 {
28 PROFILE_ABSENT,
29 PROFILE_GUESSED,
30 PROFILE_READ,
31 PROFILE_LAST /* Last value, used by profile streaming. */
32 };
33
34 /* A structure to group all the per-function control flow graph data.
35 The x_* prefixing is necessary because otherwise references to the
36 fields of this struct are interpreted as the defines for backward
37 source compatibility following the definition of this struct. */
38 struct GTY(()) control_flow_graph {
39 /* Block pointers for the exit and entry of a function.
40 These are always the head and tail of the basic block list. */
41 basic_block x_entry_block_ptr;
42 basic_block x_exit_block_ptr;
43
44 /* Index by basic block number, get basic block struct info. */
45 vec<basic_block, va_gc> *x_basic_block_info;
46
47 /* Number of basic blocks in this flow graph. */
48 int x_n_basic_blocks;
49
50 /* Number of edges in this flow graph. */
51 int x_n_edges;
52
53 /* The first free basic block number. */
54 int x_last_basic_block;
55
56 /* UIDs for LABEL_DECLs. */
57 int last_label_uid;
58
59 /* Mapping of labels to their associated blocks. At present
60 only used for the gimple CFG. */
61 vec<basic_block, va_gc> *x_label_to_block_map;
62
63 enum profile_status_d x_profile_status;
64
65 /* Whether the dominators and the postdominators are available. */
66 enum dom_state x_dom_computed[2];
67
68 /* Number of basic blocks in the dominance tree. */
69 unsigned x_n_bbs_in_dom_tree[2];
70
71 /* Maximal number of entities in the single jumptable. Used to estimate
72 final flowgraph size. */
73 int max_jumptable_ents;
74
75 /* Maximal count of BB in function. */
76 profile_count count_max;
77
78 /* Dynamically allocated edge/bb flags. */
79 int edge_flags_allocated;
80 int bb_flags_allocated;
81 };
82
83
84 extern void init_flow (function *);
85 extern void free_cfg (function *);
86 extern basic_block alloc_block (void);
87 extern void link_block (basic_block, basic_block);
88 extern void unlink_block (basic_block);
89 extern void compact_blocks (void);
90 extern void expunge_block (basic_block);
91 extern edge unchecked_make_edge (basic_block, basic_block, int);
92 extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
93 extern edge make_edge (basic_block, basic_block, int);
94 extern edge make_single_succ_edge (basic_block, basic_block, int);
95 extern void remove_edge_raw (edge);
96 extern void redirect_edge_succ (edge, basic_block);
97 extern void redirect_edge_pred (edge, basic_block);
98 extern void clear_bb_flags (void);
99 extern void dump_edge_info (FILE *, edge, dump_flags_t, int);
100 extern void debug (edge_def &ref);
101 extern void debug (edge_def *ptr);
102 extern void alloc_aux_for_blocks (int);
103 extern void clear_aux_for_blocks (void);
104 extern void free_aux_for_blocks (void);
105 extern void alloc_aux_for_edge (edge, int);
106 extern void alloc_aux_for_edges (int);
107 extern void clear_aux_for_edges (void);
108 extern void free_aux_for_edges (void);
109 extern void debug_bb (basic_block);
110 extern basic_block debug_bb_n (int);
111 extern void debug_bb (basic_block, dump_flags_t);
112 extern basic_block debug_bb_n (int, dump_flags_t);
113 extern void dump_bb_info (FILE *, basic_block, int, dump_flags_t, bool, bool);
114 extern void brief_dump_cfg (FILE *, dump_flags_t);
115 extern void update_bb_profile_for_threading (basic_block, profile_count, edge);
116 extern void scale_bbs_frequencies_profile_count (basic_block *, int,
117 profile_count, profile_count);
118 extern void scale_bbs_frequencies (basic_block *, int, profile_probability);
119 extern void initialize_original_copy_tables (void);
120 extern void reset_original_copy_tables (void);
121 extern void free_original_copy_tables (void);
122 extern bool original_copy_tables_initialized_p (void);
123 extern void set_bb_original (basic_block, basic_block);
124 extern basic_block get_bb_original (basic_block);
125 extern void set_bb_copy (basic_block, basic_block);
126 extern basic_block get_bb_copy (basic_block);
127 void set_loop_copy (class loop *, class loop *);
128 class loop *get_loop_copy (class loop *);
129
130 /* Generic RAII class to allocate a bit from storage of integer type T.
131 The allocated bit is accessible as mask with the single bit set
132 via the conversion operator to T. */
133
134 template <class T>
135 class auto_flag
136 {
137 public:
138 /* static assert T is integer type of max HOST_WIDE_INT precision. */
139 auto_flag (T *sptr)
140 {
141 m_sptr = sptr;
142 int free_bit = ffs_hwi (~*sptr);
143 /* If there are no unset bits... */
144 if (free_bit == 0)
145 gcc_unreachable ();
146 m_flag = HOST_WIDE_INT_1U << (free_bit - 1);
147 /* ...or if T is signed and thus the complement is sign-extended,
148 check if we ran out of bits. We could spare us this bit
149 if we could use C++11 std::make_unsigned<T>::type to pass
150 ~*sptr to ffs_hwi. */
151 if (m_flag == 0)
152 gcc_unreachable ();
153 gcc_checking_assert ((*sptr & m_flag) == 0);
154 *sptr |= m_flag;
155 }
156 ~auto_flag ()
157 {
158 gcc_checking_assert ((*m_sptr & m_flag) == m_flag);
159 *m_sptr &= ~m_flag;
160 }
161 operator T () const { return m_flag; }
162 private:
163 T *m_sptr;
164 T m_flag;
165 };
166
167 /* RAII class to allocate an edge flag for temporary use. You have
168 to clear the flag from all edges when you are finished using it. */
169
170 class auto_edge_flag : public auto_flag<int>
171 {
172 public:
173 auto_edge_flag (function *fun)
174 : auto_flag<int> (&fun->cfg->edge_flags_allocated) {}
175 };
176
177 /* RAII class to allocate a bb flag for temporary use. You have
178 to clear the flag from all edges when you are finished using it. */
179 class auto_bb_flag : public auto_flag<int>
180 {
181 public:
182 auto_bb_flag (function *fun)
183 : auto_flag<int> (&fun->cfg->bb_flags_allocated) {}
184 };
185
186 #endif /* GCC_CFG_H */