1 /* Interprocedural semantic function equality pass
2 Copyright (C) 2014-2020 Free Software Foundation, Inc.
3
4 Contributed by Jan Hubicka <hubicka@ucw.cz> and Martin Liska <mliska@suse.cz>
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
21
22 /* Gimple identical code folding (class func_checker) is an infrastructure
23 capable of comparing two given functions. The class compares every
24 gimple statement and uses many dictionaries to map source and target
25 SSA_NAMEs, declarations and other components.
26
27 To use the infrastructure, create an instance of func_checker and call
28 a comparison function based on type of gimple statement. */
29
30 /* Prints string STRING to a FILE with a given number of SPACE_COUNT. */
31 #define FPUTS_SPACES(file, space_count, string) \
32 fprintf (file, "%*s" string, space_count, " ");
33
34 /* fprintf function wrapper that transforms given FORMAT to follow given
35 number for SPACE_COUNT and call fprintf for a FILE. */
36 #define FPRINTF_SPACES(file, space_count, format, ...) \
37 fprintf (file, "%*s" format, space_count, " ", ##__VA_ARGS__);
38
39 /* Logs a MESSAGE to dump_file if exists and returns false. FUNC is name
40 of function and LINE is location in the source file. */
41
42 static inline bool
return_false_with_message_1(const char * message,const char * filename,const char * func,unsigned int line)43 return_false_with_message_1 (const char *message, const char *filename,
44 const char *func, unsigned int line)
45 {
46 if (dump_file && (dump_flags & TDF_DETAILS))
47 fprintf (dump_file, " false returned: '%s' in %s at %s:%u\n", message, func,
48 filename, line);
49 return false;
50 }
51
52 /* Logs a MESSAGE to dump_file if exists and returns false. */
53 #define return_false_with_msg(message) \
54 return_false_with_message_1 (message, __FILE__, __func__, __LINE__)
55
56 /* Return false and log that false value is returned. */
57 #define return_false() return_false_with_msg ("")
58
59 /* Logs return value if RESULT is false. FUNC is name of function and LINE
60 is location in the source file. */
61
62 static inline bool
return_with_result(bool result,const char * filename,const char * func,unsigned int line)63 return_with_result (bool result, const char *filename,
64 const char *func, unsigned int line)
65 {
66 if (!result && dump_file && (dump_flags & TDF_DETAILS))
67 fprintf (dump_file, " false returned: '' in %s at %s:%u\n", func,
68 filename, line);
69
70 return result;
71 }
72
73 /* Logs return value if RESULT is false. */
74 #define return_with_debug(result) return_with_result \
75 (result, __FILE__, __func__, __LINE__)
76
77 /* Verbose logging function logging statements S1 and S2 of a CODE.
78 FUNC is name of function and LINE is location in the source file. */
79
80 static inline bool
return_different_stmts_1(gimple * s1,gimple * s2,const char * code,const char * func,unsigned int line)81 return_different_stmts_1 (gimple *s1, gimple *s2, const char *code,
82 const char *func, unsigned int line)
83 {
84 if (dump_file && (dump_flags & TDF_DETAILS))
85 {
86 fprintf (dump_file, " different statement for code: %s (%s:%u):\n",
87 code, func, line);
88
89 print_gimple_stmt (dump_file, s1, 3, TDF_DETAILS);
90 print_gimple_stmt (dump_file, s2, 3, TDF_DETAILS);
91 }
92
93 return false;
94 }
95
96 /* Verbose logging function logging statements S1 and S2 of a CODE. */
97 #define return_different_stmts(s1, s2, code) \
98 return_different_stmts_1 (s1, s2, code, __func__, __LINE__)
99
100 namespace ipa_icf_gimple {
101
102 /* Basic block struct for semantic equality pass. */
103 class sem_bb
104 {
105 public:
sem_bb(basic_block bb_,unsigned nondbg_stmt_count_,unsigned edge_count_)106 sem_bb (basic_block bb_, unsigned nondbg_stmt_count_, unsigned edge_count_):
107 bb (bb_), nondbg_stmt_count (nondbg_stmt_count_), edge_count (edge_count_) {}
108
109 /* Basic block the structure belongs to. */
110 basic_block bb;
111
112 /* Number of non-debug statements in the basic block. */
113 unsigned nondbg_stmt_count;
114
115 /* Number of edges connected to the block. */
116 unsigned edge_count;
117 };
118
119 /* A class aggregating all connections and semantic equivalents
120 for a given pair of semantic function candidates. */
121 class func_checker : operand_compare
122 {
123 public:
124 /* Default constructor. */
func_checker()125 func_checker ():
126 m_source_func_decl (NULL_TREE), m_target_func_decl (NULL_TREE),
127 m_ignored_source_nodes (NULL), m_ignored_target_nodes (NULL),
128 m_ignore_labels (false)
129 {
130 m_source_ssa_names.create (0);
131 m_target_ssa_names.create (0);
132 }
133
134 /* Initialize internal structures for a given SOURCE_FUNC_DECL and
135 TARGET_FUNC_DECL. Strict polymorphic comparison is processed if
136 an option COMPARE_POLYMORPHIC is true. For special cases, one can
137 set IGNORE_LABELS to skip label comparison.
138 Similarly, IGNORE_SOURCE_DECLS and IGNORE_TARGET_DECLS are sets
139 of declarations that can be skipped. */
140 func_checker (tree source_func_decl, tree target_func_decl,
141 bool ignore_labels = false,
142 hash_set<symtab_node *> *ignored_source_nodes = NULL,
143 hash_set<symtab_node *> *ignored_target_nodes = NULL);
144
145 /* Memory release routine. */
146 virtual ~func_checker ();
147
148 /* Function visits all gimple labels and creates corresponding
149 mapping between basic blocks and labels. */
150 void parse_labels (sem_bb *bb);
151
152 /* Basic block equivalence comparison function that returns true if
153 basic blocks BB1 and BB2 correspond. */
154 bool compare_bb (sem_bb *bb1, sem_bb *bb2);
155
156 /* Verifies that trees T1 and T2 are equivalent from perspective of ICF. */
157 bool compare_ssa_name (const_tree t1, const_tree t2);
158
159 /* Verification function for edges E1 and E2. */
160 bool compare_edge (edge e1, edge e2);
161
162 /* Verifies for given GIMPLEs S1 and S2 that
163 call statements are semantically equivalent. */
164 bool compare_gimple_call (gcall *s1, gcall *s2);
165
166 /* Verifies for given GIMPLEs S1 and S2 that
167 assignment statements are semantically equivalent. */
168 bool compare_gimple_assign (gimple *s1, gimple *s2);
169
170 /* Verifies for given GIMPLEs S1 and S2 that
171 condition statements are semantically equivalent. */
172 bool compare_gimple_cond (gimple *s1, gimple *s2);
173
174 /* Verifies for given GIMPLE_LABEL stmts S1 and S2 that
175 label statements are semantically equivalent. */
176 bool compare_gimple_label (const glabel *s1, const glabel *s2);
177
178 /* Verifies for given GIMPLE_SWITCH stmts S1 and S2 that
179 switch statements are semantically equivalent. */
180 bool compare_gimple_switch (const gswitch *s1, const gswitch *s2);
181
182 /* Verifies for given GIMPLE_RETURN stmts S1 and S2 that
183 return statements are semantically equivalent. */
184 bool compare_gimple_return (const greturn *s1, const greturn *s2);
185
186 /* Verifies for given GIMPLEs S1 and S2 that
187 goto statements are semantically equivalent. */
188 bool compare_gimple_goto (gimple *s1, gimple *s2);
189
190 /* Verifies for given GIMPLE_RESX stmts S1 and S2 that
191 resx statements are semantically equivalent. */
192 bool compare_gimple_resx (const gresx *s1, const gresx *s2);
193
194 /* Verifies for given GIMPLE_ASM stmts S1 and S2 that ASM statements
195 are equivalent.
196 For the beginning, the pass only supports equality for
197 '__asm__ __volatile__ ("", "", "", "memory")'. */
198 bool compare_gimple_asm (const gasm *s1, const gasm *s2);
199
200 /* Verification function for declaration trees T1 and T2. */
201 bool compare_decl (const_tree t1, const_tree t2);
202
203 /* Function responsible for comparison of various operands T1 and T2.
204 If these components, from functions FUNC1 and FUNC2, are equal, true
205 is returned. */
206 bool compare_operand (tree t1, tree t2);
207
208 /* Compares GIMPLE ASM inputs (or outputs) where we iterate tree chain
209 and compare both TREE_PURPOSEs and TREE_VALUEs. */
210 bool compare_asm_inputs_outputs (tree t1, tree t2);
211
212 /* Verifies that trees T1 and T2, representing function declarations
213 are equivalent from perspective of ICF. */
214 bool compare_function_decl (tree t1, tree t2);
215
216 /* Verifies that trees T1 and T2 do correspond. */
217 bool compare_variable_decl (const_tree t1, const_tree t2);
218
219 /* Compare loop information for basic blocks BB1 and BB2. */
220 bool compare_loops (basic_block bb1, basic_block bb2);
221
222 /* Return true if types are compatible for polymorphic call analysis.
223 COMPARE_PTR indicates if polymorphic type comparison should be
224 done for pointers, too. */
225 static bool compatible_polymorphic_types_p (tree t1, tree t2,
226 bool compare_ptr);
227
228 /* Return true if types are compatible from perspective of ICF.
229 FIRST_ARGUMENT indicates if the comparison is called for
230 first parameter of a function. */
231 static bool compatible_types_p (tree t1, tree t2);
232
233
234 private:
235 /* Vector mapping source SSA names to target ones. */
236 vec <int> m_source_ssa_names;
237
238 /* Vector mapping target SSA names to source ones. */
239 vec <int> m_target_ssa_names;
240
241 /* Source TREE function declaration. */
242 tree m_source_func_decl;
243
244 /* Target TREE function declaration. */
245 tree m_target_func_decl;
246
247 /* Source symbol nodes that should be skipped by
248 declaration comparison. */
249 hash_set<symtab_node *> *m_ignored_source_nodes;
250
251 /* Target symbol nodes that should be skipped by
252 declaration comparison. */
253 hash_set<symtab_node *> *m_ignored_target_nodes;
254
255 /* Source to target edge map. */
256 hash_map <edge, edge> m_edge_map;
257
258 /* Source to target declaration map. */
259 hash_map <const_tree, const_tree> m_decl_map;
260
261 /* Label to basic block index mapping. */
262 hash_map <const_tree, int> m_label_bb_map;
263
264 /* Flag if ignore labels in comparison. */
265 bool m_ignore_labels;
266
267 public:
268 /* Return true if two operands are equal. The flags fields can be used
269 to specify OEP flags described above. */
270 virtual bool operand_equal_p (const_tree, const_tree, unsigned int flags);
271
272 /* Generate a hash value for an expression. This can be used iteratively
273 by passing a previous result as the HSTATE argument. */
274 virtual void hash_operand (const_tree, inchash::hash &, unsigned flags);
275 };
276
277 } // ipa_icf_gimple namespace
278