gcc/ipa-icf-gimple.h

   1 /* Interprocedural semantic function equality pass
   2    Copyright (C) 2014-2021 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
  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
  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
  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:
 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 : ao_compare
 122 {
 123 public:
 124   /* Default constructor.  */
 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), m_tbaa (true)
 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                 bool tbaa = true,
 143                 hash_set<symtab_node *> *ignored_source_nodes = NULL,
 144                 hash_set<symtab_node *> *ignored_target_nodes = NULL);
 145
 146   /* Memory release routine.  */
 147   virtual ~func_checker ();
 148
 149   /* Function visits all gimple labels and creates corresponding
 150      mapping between basic blocks and labels.  */
 151   void parse_labels (sem_bb *bb);
 152
 153   /* Basic block equivalence comparison function that returns true if
 154      basic blocks BB1 and BB2 correspond.  */
 155   bool compare_bb (sem_bb *bb1, sem_bb *bb2);
 156
 157   /* Verifies that trees T1 and T2 are equivalent from perspective of ICF.  */
 158   bool compare_ssa_name (const_tree t1, const_tree t2);
 159
 160   /* Verification function for edges E1 and E2.  */
 161   bool compare_edge (edge e1, edge e2);
 162
 163   /* Verifies for given GIMPLEs S1 and S2 that
 164      call statements are semantically equivalent.  */
 165   bool compare_gimple_call (gcall *s1, gcall *s2);
 166
 167   /* Verifies for given GIMPLEs S1 and S2 that
 168      assignment statements are semantically equivalent.  */
 169   bool compare_gimple_assign (gimple *s1, gimple *s2);
 170
 171   /* Verifies for given GIMPLEs S1 and S2 that
 172      condition statements are semantically equivalent.  */
 173   bool compare_gimple_cond (gimple *s1, gimple *s2);
 174
 175   /* Verifies for given GIMPLE_LABEL stmts S1 and S2 that
 176      label statements are semantically equivalent.  */
 177   bool compare_gimple_label (const glabel *s1, const glabel *s2);
 178
 179   /* Verifies for given GIMPLE_SWITCH stmts S1 and S2 that
 180      switch statements are semantically equivalent.  */
 181   bool compare_gimple_switch (const gswitch *s1, const gswitch *s2);
 182
 183   /* Verifies for given GIMPLE_RETURN stmts S1 and S2 that
 184      return statements are semantically equivalent.  */
 185   bool compare_gimple_return (const greturn *s1, const greturn *s2);
 186
 187   /* Verifies for given GIMPLEs S1 and S2 that
 188      goto statements are semantically equivalent.  */
 189   bool compare_gimple_goto (gimple *s1, gimple *s2);
 190
 191   /* Verifies for given GIMPLE_RESX stmts S1 and S2 that
 192      resx statements are semantically equivalent.  */
 193   bool compare_gimple_resx (const gresx *s1, const gresx *s2);
 194
 195   /* Verifies for given GIMPLE_ASM stmts S1 and S2 that ASM statements
 196      are equivalent.
 197      For the beginning, the pass only supports equality for
 198      '__asm__ __volatile__ ("", "", "", "memory")'.  */
 199   bool compare_gimple_asm (const gasm *s1, const gasm *s2);
 200
 201   /* Verification function for declaration trees T1 and T2.  */
 202   bool compare_decl (const_tree t1, const_tree t2);
 203
 204   /* Compute hash map MAP that determines loads and stores of STMT.  */
 205   enum operand_access_type {OP_MEMORY, OP_NORMAL};
 206   typedef hash_set<tree> operand_access_type_map;
 207
 208   /* Function responsible for comparison of various operands T1 and T2.
 209      If these components, from functions FUNC1 and FUNC2, are equal, true
 210      is returned.  */
 211   bool compare_operand (tree t1, tree t2, operand_access_type type);
 212
 213   /* Compares GIMPLE ASM inputs (or outputs) where we iterate tree chain
 214      and compare both TREE_PURPOSEs and TREE_VALUEs.  */
 215   bool compare_asm_inputs_outputs (tree t1, tree t2,
 216                                    operand_access_type_map *map);
 217
 218   /* Verifies that trees T1 and T2, representing function declarations
 219      are equivalent from perspective of ICF.  */
 220   bool compare_function_decl (tree t1, tree t2);
 221
 222   /* Verifies that trees T1 and T2 do correspond.  */
 223   bool compare_variable_decl (const_tree t1, const_tree t2);
 224
 225   /* Compare loop information for basic blocks BB1 and BB2.  */
 226   bool compare_loops (basic_block bb1, basic_block bb2);
 227
 228   /* Return true if types are compatible for polymorphic call analysis.
 229      COMPARE_PTR indicates if polymorphic type comparison should be
 230      done for pointers, too.  */
 231   static bool compatible_polymorphic_types_p (tree t1, tree t2,
 232                                               bool compare_ptr);
 233
 234   /* Return true if types are compatible from perspective of ICF.
 235      FIRST_ARGUMENT indicates if the comparison is called for
 236      first parameter of a function.  */
 237   static bool compatible_types_p (tree t1, tree t2);
 238
 239   /* Compute hash map determining access types of operands.  */
 240   static void classify_operands (const gimple *stmt,
 241                                  operand_access_type_map *map);
 242
 243   /* Return access type of a given operand.  */
 244   static operand_access_type get_operand_access_type
 245                  (operand_access_type_map *map, tree);
 246 private:
 247   /* Vector mapping source SSA names to target ones.  */
 248   vec <int> m_source_ssa_names;
 249
 250   /* Vector mapping target SSA names to source ones.  */
 251   vec <int> m_target_ssa_names;
 252
 253   /* Source TREE function declaration.  */
 254   tree m_source_func_decl;
 255
 256   /* Target TREE function declaration.  */
 257   tree m_target_func_decl;
 258
 259   /* Source symbol nodes that should be skipped by
 260      declaration comparison.  */
 261   hash_set<symtab_node *> *m_ignored_source_nodes;
 262
 263   /* Target symbol nodes that should be skipped by
 264      declaration comparison.  */
 265   hash_set<symtab_node *> *m_ignored_target_nodes;
 266
 267   /* Source to target edge map.  */
 268   hash_map <edge, edge> m_edge_map;
 269
 270   /* Source to target declaration map.  */
 271   hash_map <const_tree, const_tree> m_decl_map;
 272
 273   /* Label to basic block index mapping.  */
 274   hash_map <const_tree, int> m_label_bb_map;
 275
 276   /* Flag if ignore labels in comparison.  */
 277   bool m_ignore_labels;
 278
 279   /* Flag if we should compare type based alias analysis info.  */
 280   bool m_tbaa;
 281
 282 public:
 283   /* Return true if two operands are equal.  The flags fields can be used
 284      to specify OEP flags described above.  */
 285   virtual bool operand_equal_p (const_tree, const_tree, unsigned int flags);
 286
 287   /* Generate a hash value for an expression.  This can be used iteratively
 288      by passing a previous result as the HSTATE argument.  */
 289   virtual void hash_operand (const_tree, inchash::hash &, unsigned flags);
 290   void hash_operand (const_tree, inchash::hash &, unsigned flags,
 291                      operand_access_type access);
 292 };
 293
 294 } // ipa_icf_gimple namespace