1/* Control flow graph manipulation code header file.
2 Copyright (C) 2014-2025 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along 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. */
26enum 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. */
38struct 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 /* Set if the profile is computed on every edge and basic block. */
83 bool full_profile;
84};
85
86
87extern void init_flow (function *);
88extern void free_cfg (function *);
89extern basic_block alloc_block (void);
90extern void link_block (basic_block, basic_block);
91extern void unlink_block (basic_block);
92extern void compact_blocks (void);
93extern void expunge_block (basic_block);
94extern edge unchecked_make_edge (basic_block, basic_block, int);
95extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
96extern edge make_edge (basic_block, basic_block, int);
97extern edge make_single_succ_edge (basic_block, basic_block, int);
98extern void remove_edge_raw (edge);
99extern void redirect_edge_succ (edge, basic_block);
100extern void redirect_edge_pred (edge, basic_block);
101extern void clear_bb_flags (void);
102extern void dump_edge_info (FILE *, edge, dump_flags_t, int);
103extern void debug (edge_def &ref);
104extern void debug (edge_def *ptr);
105extern void alloc_aux_for_blocks (int);
106extern void clear_aux_for_blocks (void);
107extern void free_aux_for_blocks (void);
108extern void alloc_aux_for_edge (edge, int);
109extern void alloc_aux_for_edges (int);
110extern void clear_aux_for_edges (void);
111extern void free_aux_for_edges (void);
112extern void debug_bb (basic_block);
113extern basic_block debug_bb_n (int);
114extern void debug_bb (basic_block, dump_flags_t);
115extern basic_block debug_bb_n (int, dump_flags_t);
116extern void dump_bb_info (FILE *, basic_block, int, dump_flags_t, bool, bool);
117extern void brief_dump_cfg (FILE *, dump_flags_t);
118extern void set_edge_probability_and_rescale_others (edge, profile_probability);
119extern void update_bb_profile_for_threading (basic_block, profile_count, edge);
120extern void scale_bbs_frequencies_profile_count (basic_block *, int,
121 profile_count, profile_count);
122extern void scale_bbs_frequencies (basic_block *, int, profile_probability);
123extern void initialize_original_copy_tables (void);
124extern void reset_original_copy_tables (void);
125extern void free_original_copy_tables (void);
126extern bool original_copy_tables_initialized_p (void);
127extern void set_bb_original (basic_block, basic_block);
128extern basic_block get_bb_original (basic_block);
129extern void set_bb_copy (basic_block, basic_block);
130extern basic_block get_bb_copy (basic_block);
131void set_loop_copy (class loop *, class loop *);
132class loop *get_loop_copy (class loop *);
133void scale_strictly_dominated_blocks (basic_block,
134 profile_count, profile_count);
135
136/* Generic RAII class to allocate a bit from storage of integer type T.
137 The allocated bit is accessible as mask with the single bit set
138 via the conversion operator to T. */
139
140template <class T>
141class auto_flag
142{
143public:
144 /* static assert T is integer type of max HOST_WIDE_INT precision. */
145 auto_flag (T *sptr)
146 {
147 m_sptr = sptr;
148 int free_bit = ffs_hwi (~*sptr);
149 /* If there are no unset bits... */
150 if (free_bit == 0)
151 gcc_unreachable ();
152 m_flag = HOST_WIDE_INT_1U << (free_bit - 1);
153 /* ...or if T is signed and thus the complement is sign-extended,
154 check if we ran out of bits. We could spare us this bit
155 if we could use C++11 std::make_unsigned<T>::type to pass
156 ~*sptr to ffs_hwi. */
157 if (m_flag == 0)
158 gcc_unreachable ();
159 gcc_checking_assert ((*sptr & m_flag) == 0);
160 *sptr |= m_flag;
161 }
162 ~auto_flag ()
163 {
164 gcc_checking_assert ((*m_sptr & m_flag) == m_flag);
165 *m_sptr &= ~m_flag;
166 }
167 operator T () const { return m_flag; }
168private:
169 T *m_sptr;
170 T m_flag;
171};
172
173/* RAII class to allocate an edge flag for temporary use. You have
174 to clear the flag from all edges when you are finished using it. */
175
176class auto_edge_flag : public auto_flag<int>
177{
178public:
179 auto_edge_flag (function *fun)
180 : auto_flag<int> (&fun->cfg->edge_flags_allocated) {}
181};
182
183/* RAII class to allocate a bb flag for temporary use. You have
184 to clear the flag from all edges when you are finished using it. */
185class auto_bb_flag : public auto_flag<int>
186{
187public:
188 auto_bb_flag (function *fun)
189 : auto_flag<int> (&fun->cfg->bb_flags_allocated) {}
190};
191
192#endif /* GCC_CFG_H */
193

source code of gcc/cfg.h