tree-ssa-alias.h

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/* Tree based alias analysis and alias oracle.
   Copyright (C) 2008-2026 Free Software Foundation, Inc.
   Contributed by Richard Guenther  <rguenther@suse.de>
 
   This file is part of GCC.
 
   GCC is free software; you can redistribute it and/or modify
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
 
   GCC is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with GCC; see the file COPYING3.  If not see
   <http://www.gnu.org/licenses/>.  */
 
#ifndef TREE_SSA_ALIAS_H
#define TREE_SSA_ALIAS_H
 
/* The points-to solution.
 
   The points-to solution is a union of pt_vars and the abstract
   sets specified by the flags.  */
struct GTY(()) pt_solution
{
  /* Nonzero if points-to analysis couldn't determine where this pointer
     is pointing to.  */
  unsigned int anything : 1;
 
  /* Nonzero if the points-to set includes any global memory.  Note that
     even if this is zero pt_vars can still include global variables.  */
  unsigned int nonlocal : 1;
 
  /* Nonzero if the points-to set includes the local escaped solution by
     reference.  */
  unsigned int escaped : 1;
 
  /* Nonzero if the points-to set includes the IPA escaped solution by
     reference.  */
  unsigned int ipa_escaped : 1;
 
  /* Nonzero if the points-to set includes 'nothing', the points-to set
     includes memory at address NULL.  */
  unsigned int null : 1;
 
  /* Nonzero if the points-to set includes a readonly object like a
     STRING_CST that does not have an underlying declaration but will
     end up in the constant pool.  */
  unsigned int const_pool : 1;
 
  /* Nonzero if the vars bitmap includes a variable included in 'nonlocal'.  */
  unsigned int vars_contains_nonlocal : 1;
  /* Nonzero if the vars bitmap includes a local automatic variable.  */
  unsigned int vars_contains_auto : 1;
  /* Nonzero if the vars bitmap includes a variable included in 'escaped'.  */
  unsigned int vars_contains_escaped : 1;
  /* Nonzero if the vars bitmap includes a anonymous heap variable that
     escaped the function and thus became global.  */
  unsigned int vars_contains_escaped_heap : 1;
  /* Nonzero if the vars bitmap includes a anonymous variable used to
     represent storage pointed to by a restrict qualified pointer.  */
  unsigned int vars_contains_restrict : 1;
  /* Nonzero if the vars bitmap includes an interposable variable.  */
  unsigned int vars_contains_interposable : 1;
 
  /* Set of variables that this pointer may point to.  */
  bitmap vars;
};
 
 
/* Simplified and cached information about a memory reference tree.
   Used by the alias-oracle internally and externally in alternate
   interfaces.  */
class ao_ref
{
public:
  /* The original full memory reference tree or NULL_TREE if that is
     not available.  */
  tree ref;
 
  /* The following fields are the decomposed reference as returned
     by get_ref_base_and_extent.  */
  /* The base object of the memory reference or NULL_TREE if all of
     the following fields are not yet computed.  */
  tree base;
  /* The offset relative to the base.  */
  poly_int64 offset;
  /* The size of the access.  */
  poly_int64 size;
  /* The maximum possible extent of the access or -1 if unconstrained.  */
  poly_int64 max_size;
 
  /* The alias set of the access or -1 if not yet computed.  */
  alias_set_type ref_alias_set;
 
  /* The alias set of the base object or -1 if not yet computed.  */
  alias_set_type base_alias_set;
 
  /* Whether the memory is considered a volatile access.  */
  bool volatile_p;
 
  bool max_size_known_p () const;
};
 
/* Return true if the maximum size is known, rather than the special -1
   marker.  */
 
inline bool
ao_ref::max_size_known_p () const
{
  return known_size_p (max_size);
}
 
/* In tree-ssa-alias.cc  */
extern void ao_ref_init (ao_ref *, tree);
extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
extern void ao_ref_init_from_ptr_and_range (ao_ref *, tree, bool,
                                            poly_int64, poly_int64,
                                            poly_int64);
extern tree ao_ref_base (ao_ref *);
extern alias_set_type ao_ref_alias_set (ao_ref *);
extern alias_set_type ao_ref_base_alias_set (ao_ref *);
extern tree ao_ref_alias_ptr_type (ao_ref *);
extern tree ao_ref_base_alias_ptr_type (ao_ref *);
extern bool ao_ref_alignment (ao_ref *, unsigned int *,
                              unsigned HOST_WIDE_INT *);
extern bool ptr_deref_may_alias_global_p (tree, bool);
extern bool ptr_deref_may_alias_auto_p (tree);
extern bool ptr_derefs_may_alias_p (tree, tree);
extern bool ptrs_compare_unequal (tree, tree);
extern bool ref_may_alias_global_p (tree, bool);
extern bool ref_may_alias_global_p (ao_ref *, bool);
extern bool refs_may_alias_p (tree, tree, bool = true);
extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
extern bool refs_anti_dependent_p (tree, tree);
extern bool refs_output_dependent_p (tree, tree);
extern bool ref_maybe_used_by_stmt_p (gimple *, tree, bool = true);
extern bool ref_maybe_used_by_stmt_p (gimple *, ao_ref *, bool = true);
extern bool stmt_may_clobber_global_p (gimple *, bool);
extern bool stmt_may_clobber_ref_p (gimple *, tree, bool = true);
extern bool stmt_may_clobber_ref_p_1 (gimple *, ao_ref *, bool = true);
extern bool call_may_clobber_ref_p (gcall *, tree, bool = true);
extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *, bool = true);
extern bool stmt_kills_ref_p (gimple *, tree);
extern bool stmt_kills_ref_p (gimple *, ao_ref *);
extern bool ref_can_have_store_data_races (tree);
 
enum translate_flags
  { TR_TRANSLATE, TR_VALUEIZE_AND_DISAMBIGUATE, TR_DISAMBIGUATE };
extern tree get_continuation_for_phi (gphi *, ao_ref *, bool,
                                      unsigned int &, bitmap *, bool,
                                      void *(*)(ao_ref *, tree, void *,
                                                translate_flags *),
                                      void *,
                                      bool (*)(edge, void *) = nullptr,
                                      translate_flags
                                        = TR_VALUEIZE_AND_DISAMBIGUATE);
extern void *walk_non_aliased_vuses (ao_ref *, tree, bool,
                                     void *(*)(ao_ref *, tree, void *),
                                     void *(*)(ao_ref *, tree, void *,
                                               translate_flags *),
                                     bool (*)(edge, void *),
                                     tree (*)(tree), unsigned &, void *);
extern int walk_aliased_vdefs (ao_ref *, tree,
                               bool (*)(ao_ref *, tree, void *),
                               void *, bitmap *,
                               bool *function_entry_reached = NULL,
                               unsigned int limit = 0);
extern void dump_alias_info (FILE *);
extern void debug_alias_info (void);
extern void dump_points_to_solution (FILE *, struct pt_solution *);
extern void debug (pt_solution &ref);
extern void debug (pt_solution *ptr);
extern void dump_points_to_info_for (FILE *, tree);
extern void debug_points_to_info_for (tree);
extern void dump_alias_stats (FILE *);
 
 
/* In tree-ssa-structalias.cc  */
extern unsigned int compute_may_aliases (void);
extern bool pt_solution_empty_p (const pt_solution *);
extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
extern bool pt_solution_includes_global (struct pt_solution *, bool);
extern bool pt_solution_includes_auto (struct pt_solution *);
extern bool pt_solution_includes (struct pt_solution *, const_tree);
extern bool pt_solution_includes_const_pool (struct pt_solution *);
extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
extern void pt_solution_reset (struct pt_solution *);
extern void pt_solution_set (struct pt_solution *, bitmap, bool);
extern void pt_solution_set_var (struct pt_solution *, tree);
 
extern void dump_pta_stats (FILE *);
 
extern GTY(()) struct pt_solution ipa_escaped_pt;
 
/* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
   overlap.  SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
   range is open-ended.  Otherwise return false.  */
 
inline bool
ranges_overlap_p (HOST_WIDE_INT pos1,
                  unsigned HOST_WIDE_INT size1,
                  HOST_WIDE_INT pos2,
                  unsigned HOST_WIDE_INT size2)
{
  if (size1 == 0 || size2 == 0)
    return false;
  if (pos1 >= pos2
      && (size2 == (unsigned HOST_WIDE_INT)-1
          || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
    return true;
  if (pos2 >= pos1
      && (size1 == (unsigned HOST_WIDE_INT)-1
          || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
    return true;
 
  return false;
}
 
 
 
#endif /* TREE_SSA_ALIAS_H  */