gcc/tree-ssa-alias.h

   1 /* Tree based alias analysis and alias oracle.
   2    Copyright (C) 2008-2025 Free Software Foundation, Inc.
   3    Contributed by Richard Guenther  <rguenther@suse.de>
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    GCC is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License 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 TREE_SSA_ALIAS_H
  22 #define TREE_SSA_ALIAS_H
  23
  24 /* The points-to solution.
  25
  26    The points-to solution is a union of pt_vars and the abstract
  27    sets specified by the flags.  */
  28 struct GTY(()) pt_solution
  29 {
  30   /* Nonzero if points-to analysis couldn't determine where this pointer
  31      is pointing to.  */
  32   unsigned int anything : 1;
  33
  34   /* Nonzero if the points-to set includes any global memory.  Note that
  35      even if this is zero pt_vars can still include global variables.  */
  36   unsigned int nonlocal : 1;
  37
  38   /* Nonzero if the points-to set includes the local escaped solution by
  39      reference.  */
  40   unsigned int escaped : 1;
  41
  42   /* Nonzero if the points-to set includes the IPA escaped solution by
  43      reference.  */
  44   unsigned int ipa_escaped : 1;
  45
  46   /* Nonzero if the points-to set includes 'nothing', the points-to set
  47      includes memory at address NULL.  */
  48   unsigned int null : 1;
  49
  50   /* Nonzero if the points-to set includes a readonly object like a
  51      STRING_CST that does not have an underlying declaration but will
  52      end up in the constant pool.  */
  53   unsigned int const_pool : 1;
  54
  55   /* Nonzero if the vars bitmap includes a variable included in 'nonlocal'.  */
  56   unsigned int vars_contains_nonlocal : 1;
  57   /* Nonzero if the vars bitmap includes a variable included in 'escaped'.  */
  58   unsigned int vars_contains_escaped : 1;
  59   /* Nonzero if the vars bitmap includes a anonymous heap variable that
  60      escaped the function and thus became global.  */
  61   unsigned int vars_contains_escaped_heap : 1;
  62   /* Nonzero if the vars bitmap includes a anonymous variable used to
  63      represent storage pointed to by a restrict qualified pointer.  */
  64   unsigned int vars_contains_restrict : 1;
  65   /* Nonzero if the vars bitmap includes an interposable variable.  */
  66   unsigned int vars_contains_interposable : 1;
  67
  68   /* Set of variables that this pointer may point to.  */
  69   bitmap vars;
  70 };
  71
  72
  73 /* Simplified and cached information about a memory reference tree.
  74    Used by the alias-oracle internally and externally in alternate
  75    interfaces.  */
  76 class ao_ref
  77 {
  78 public:
  79   /* The original full memory reference tree or NULL_TREE if that is
  80      not available.  */
  81   tree ref;
  82
  83   /* The following fields are the decomposed reference as returned
  84      by get_ref_base_and_extent.  */
  85   /* The base object of the memory reference or NULL_TREE if all of
  86      the following fields are not yet computed.  */
  87   tree base;
  88   /* The offset relative to the base.  */
  89   poly_int64 offset;
  90   /* The size of the access.  */
  91   poly_int64 size;
  92   /* The maximum possible extent of the access or -1 if unconstrained.  */
  93   poly_int64 max_size;
  94
  95   /* The alias set of the access or -1 if not yet computed.  */
  96   alias_set_type ref_alias_set;
  97
  98   /* The alias set of the base object or -1 if not yet computed.  */
  99   alias_set_type base_alias_set;
 100
 101   /* Whether the memory is considered a volatile access.  */
 102   bool volatile_p;
 103
 104   bool max_size_known_p () const;
 105 };
 106
 107 /* Return true if the maximum size is known, rather than the special -1
 108    marker.  */
 109
 110 inline bool
 111 ao_ref::max_size_known_p () const
 112 {
 113   return known_size_p (max_size);
 114 }
 115
 116 /* In tree-ssa-alias.cc  */
 117 extern void ao_ref_init (ao_ref *, tree);
 118 extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
 119 extern void ao_ref_init_from_ptr_and_range (ao_ref *, tree, bool,
 120                                             poly_int64, poly_int64,
 121                                             poly_int64);
 122 extern tree ao_ref_base (ao_ref *);
 123 extern alias_set_type ao_ref_alias_set (ao_ref *);
 124 extern alias_set_type ao_ref_base_alias_set (ao_ref *);
 125 extern tree ao_ref_alias_ptr_type (ao_ref *);
 126 extern tree ao_ref_base_alias_ptr_type (ao_ref *);
 127 extern bool ao_ref_alignment (ao_ref *, unsigned int *,
 128                               unsigned HOST_WIDE_INT *);
 129 extern bool ptr_deref_may_alias_global_p (tree, bool);
 130 extern bool ptr_derefs_may_alias_p (tree, tree);
 131 extern bool ptrs_compare_unequal (tree, tree);
 132 extern bool ref_may_alias_global_p (tree, bool);
 133 extern bool ref_may_alias_global_p (ao_ref *, bool);
 134 extern bool refs_may_alias_p (tree, tree, bool = true);
 135 extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
 136 extern bool refs_anti_dependent_p (tree, tree);
 137 extern bool refs_output_dependent_p (tree, tree);
 138 extern bool ref_maybe_used_by_stmt_p (gimple *, tree, bool = true);
 139 extern bool ref_maybe_used_by_stmt_p (gimple *, ao_ref *, bool = true);
 140 extern bool stmt_may_clobber_global_p (gimple *, bool);
 141 extern bool stmt_may_clobber_ref_p (gimple *, tree, bool = true);
 142 extern bool stmt_may_clobber_ref_p_1 (gimple *, ao_ref *, bool = true);
 143 extern bool call_may_clobber_ref_p (gcall *, tree, bool = true);
 144 extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *, bool = true);
 145 extern bool stmt_kills_ref_p (gimple *, tree);
 146 extern bool stmt_kills_ref_p (gimple *, ao_ref *);
 147 extern bool ref_can_have_store_data_races (tree);
 148
 149 enum translate_flags
 150   { TR_TRANSLATE, TR_VALUEIZE_AND_DISAMBIGUATE, TR_DISAMBIGUATE };
 151 extern tree get_continuation_for_phi (gimple *, ao_ref *, bool,
 152                                       unsigned int &, bitmap *, bool,
 153                                       void *(*)(ao_ref *, tree, void *,
 154                                                 translate_flags *),
 155                                       void *, translate_flags
 156                                         = TR_VALUEIZE_AND_DISAMBIGUATE);
 157 extern void *walk_non_aliased_vuses (ao_ref *, tree, bool,
 158                                      void *(*)(ao_ref *, tree, void *),
 159                                      void *(*)(ao_ref *, tree, void *,
 160                                                translate_flags *),
 161                                      tree (*)(tree), unsigned &, void *);
 162 extern int walk_aliased_vdefs (ao_ref *, tree,
 163                                bool (*)(ao_ref *, tree, void *),
 164                                void *, bitmap *,
 165                                bool *function_entry_reached = NULL,
 166                                unsigned int limit = 0);
 167 extern void dump_alias_info (FILE *);
 168 extern void debug_alias_info (void);
 169 extern void dump_points_to_solution (FILE *, struct pt_solution *);
 170 extern void debug (pt_solution &ref);
 171 extern void debug (pt_solution *ptr);
 172 extern void dump_points_to_info_for (FILE *, tree);
 173 extern void debug_points_to_info_for (tree);
 174 extern void dump_alias_stats (FILE *);
 175
 176
 177 /* In tree-ssa-structalias.cc  */
 178 extern unsigned int compute_may_aliases (void);
 179 extern bool pt_solution_empty_p (const pt_solution *);
 180 extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
 181 extern bool pt_solution_includes_global (struct pt_solution *, bool);
 182 extern bool pt_solution_includes (struct pt_solution *, const_tree);
 183 extern bool pt_solution_includes_const_pool (struct pt_solution *);
 184 extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
 185 extern void pt_solution_reset (struct pt_solution *);
 186 extern void pt_solution_set (struct pt_solution *, bitmap, bool);
 187 extern void pt_solution_set_var (struct pt_solution *, tree);
 188
 189 extern void dump_pta_stats (FILE *);
 190
 191 extern GTY(()) struct pt_solution ipa_escaped_pt;
 192
 193 /* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
 194    overlap.  SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
 195    range is open-ended.  Otherwise return false.  */
 196
 197 inline bool
 198 ranges_overlap_p (HOST_WIDE_INT pos1,
 199                   unsigned HOST_WIDE_INT size1,
 200                   HOST_WIDE_INT pos2,
 201                   unsigned HOST_WIDE_INT size2)
 202 {
 203   if (size1 == 0 || size2 == 0)
 204     return false;
 205   if (pos1 >= pos2
 206       && (size2 == (unsigned HOST_WIDE_INT)-1
 207           || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
 208     return true;
 209   if (pos2 >= pos1
 210       && (size1 == (unsigned HOST_WIDE_INT)-1
 211           || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
 212     return true;
 213
 214   return false;
 215 }
 216
 217
 218
 219 #endif /* TREE_SSA_ALIAS_H  */