gcc/tree-ssa-alias.h

   1 /* Tree based alias analysis and alias oracle.
   2    Copyright (C) 2008-2022 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 vars bitmap includes a variable included in 'nonlocal'.  */
  51   unsigned int vars_contains_nonlocal : 1;
  52   /* Nonzero if the vars bitmap includes a variable included in 'escaped'.  */
  53   unsigned int vars_contains_escaped : 1;
  54   /* Nonzero if the vars bitmap includes a anonymous heap variable that
  55      escaped the function and thus became global.  */
  56   unsigned int vars_contains_escaped_heap : 1;
  57   /* Nonzero if the vars bitmap includes a anonymous variable used to
  58      represent storage pointed to by a restrict qualified pointer.  */
  59   unsigned int vars_contains_restrict : 1;
  60   /* Nonzero if the vars bitmap includes an interposable variable.  */
  61   unsigned int vars_contains_interposable : 1;
  62
  63   /* Set of variables that this pointer may point to.  */
  64   bitmap vars;
  65 };
  66
  67
  68 /* Simplified and cached information about a memory reference tree.
  69    Used by the alias-oracle internally and externally in alternate
  70    interfaces.  */
  71 class ao_ref
  72 {
  73 public:
  74   /* The original full memory reference tree or NULL_TREE if that is
  75      not available.  */
  76   tree ref;
  77
  78   /* The following fields are the decomposed reference as returned
  79      by get_ref_base_and_extent.  */
  80   /* The base object of the memory reference or NULL_TREE if all of
  81      the following fields are not yet computed.  */
  82   tree base;
  83   /* The offset relative to the base.  */
  84   poly_int64 offset;
  85   /* The size of the access.  */
  86   poly_int64 size;
  87   /* The maximum possible extent of the access or -1 if unconstrained.  */
  88   poly_int64 max_size;
  89
  90   /* The alias set of the access or -1 if not yet computed.  */
  91   alias_set_type ref_alias_set;
  92
  93   /* The alias set of the base object or -1 if not yet computed.  */
  94   alias_set_type base_alias_set;
  95
  96   /* Whether the memory is considered a volatile access.  */
  97   bool volatile_p;
  98
  99   bool max_size_known_p () const;
 100 };
 101
 102 /* Return true if the maximum size is known, rather than the special -1
 103    marker.  */
 104
 105 inline bool
 106 ao_ref::max_size_known_p () const
 107 {
 108   return known_size_p (max_size);
 109 }
 110
 111 /* In tree-ssa-alias.cc  */
 112 extern void ao_ref_init (ao_ref *, tree);
 113 extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
 114 extern void ao_ref_init_from_ptr_and_range (ao_ref *, tree, bool,
 115                                             poly_int64, poly_int64,
 116                                             poly_int64);
 117 extern tree ao_ref_base (ao_ref *);
 118 extern alias_set_type ao_ref_alias_set (ao_ref *);
 119 extern alias_set_type ao_ref_base_alias_set (ao_ref *);
 120 extern tree ao_ref_alias_ptr_type (ao_ref *);
 121 extern tree ao_ref_base_alias_ptr_type (ao_ref *);
 122 extern bool ao_ref_alignment (ao_ref *, unsigned int *,
 123                               unsigned HOST_WIDE_INT *);
 124 extern bool ptr_deref_may_alias_global_p (tree, bool);
 125 extern bool ptr_derefs_may_alias_p (tree, tree);
 126 extern bool ptrs_compare_unequal (tree, tree);
 127 extern bool ref_may_alias_global_p (tree, bool);
 128 extern bool ref_may_alias_global_p (ao_ref *, bool);
 129 extern bool refs_may_alias_p (tree, tree, bool = true);
 130 extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
 131 extern bool refs_anti_dependent_p (tree, tree);
 132 extern bool refs_output_dependent_p (tree, tree);
 133 extern bool ref_maybe_used_by_stmt_p (gimple *, tree, bool = true);
 134 extern bool ref_maybe_used_by_stmt_p (gimple *, ao_ref *, bool = true);
 135 extern bool stmt_may_clobber_global_p (gimple *, bool);
 136 extern bool stmt_may_clobber_ref_p (gimple *, tree, bool = true);
 137 extern bool stmt_may_clobber_ref_p_1 (gimple *, ao_ref *, bool = true);
 138 extern bool call_may_clobber_ref_p (gcall *, tree, bool = true);
 139 extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *, bool = true);
 140 extern bool stmt_kills_ref_p (gimple *, tree);
 141 extern bool stmt_kills_ref_p (gimple *, ao_ref *);
 142 enum translate_flags
 143   { TR_TRANSLATE, TR_VALUEIZE_AND_DISAMBIGUATE, TR_DISAMBIGUATE };
 144 extern tree get_continuation_for_phi (gimple *, ao_ref *, bool,
 145                                       unsigned int &, bitmap *, bool,
 146                                       void *(*)(ao_ref *, tree, void *,
 147                                                 translate_flags *),
 148                                       void *, translate_flags
 149                                         = TR_VALUEIZE_AND_DISAMBIGUATE);
 150 extern void *walk_non_aliased_vuses (ao_ref *, tree, bool,
 151                                      void *(*)(ao_ref *, tree, void *),
 152                                      void *(*)(ao_ref *, tree, void *,
 153                                                translate_flags *),
 154                                      tree (*)(tree), unsigned &, void *);
 155 extern int walk_aliased_vdefs (ao_ref *, tree,
 156                                bool (*)(ao_ref *, tree, void *),
 157                                void *, bitmap *,
 158                                bool *function_entry_reached = NULL,
 159                                unsigned int limit = 0);
 160 extern void dump_alias_info (FILE *);
 161 extern void debug_alias_info (void);
 162 extern void dump_points_to_solution (FILE *, struct pt_solution *);
 163 extern void debug (pt_solution &ref);
 164 extern void debug (pt_solution *ptr);
 165 extern void dump_points_to_info_for (FILE *, tree);
 166 extern void debug_points_to_info_for (tree);
 167 extern void dump_alias_stats (FILE *);
 168
 169
 170 /* In tree-ssa-structalias.cc  */
 171 extern unsigned int compute_may_aliases (void);
 172 extern bool pt_solution_empty_p (const pt_solution *);
 173 extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
 174 extern bool pt_solution_includes_global (struct pt_solution *, bool);
 175 extern bool pt_solution_includes (struct pt_solution *, const_tree);
 176 extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
 177 extern void pt_solution_reset (struct pt_solution *);
 178 extern void pt_solution_set (struct pt_solution *, bitmap, bool);
 179 extern void pt_solution_set_var (struct pt_solution *, tree);
 180
 181 extern void dump_pta_stats (FILE *);
 182
 183 extern GTY(()) struct pt_solution ipa_escaped_pt;
 184
 185 /* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
 186    overlap.  SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
 187    range is open-ended.  Otherwise return false.  */
 188
 189 static inline bool
 190 ranges_overlap_p (HOST_WIDE_INT pos1,
 191                   unsigned HOST_WIDE_INT size1,
 192                   HOST_WIDE_INT pos2,
 193                   unsigned HOST_WIDE_INT size2)
 194 {
 195   if (size1 == 0 || size2 == 0)
 196     return false;
 197   if (pos1 >= pos2
 198       && (size2 == (unsigned HOST_WIDE_INT)-1
 199           || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
 200     return true;
 201   if (pos2 >= pos1
 202       && (size1 == (unsigned HOST_WIDE_INT)-1
 203           || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
 204     return true;
 205
 206   return false;
 207 }
 208
 209
 210
 211 #endif /* TREE_SSA_ALIAS_H  */