gcc/tree-ssa-alias.h

   1 /* Tree based alias analysis and alias oracle.
   2    Copyright (C) 2008 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 #include "coretypes.h"
  25
  26
  27 /* The reasons a variable may escape a function.  */
  28 enum escape_type
  29 {
  30   NO_ESCAPE = 0,                        /* Doesn't escape.  */
  31   ESCAPE_STORED_IN_GLOBAL = 1 << 0,
  32   ESCAPE_TO_ASM = 1 << 1,               /* Passed by address to an assembly
  33                                            statement.  */
  34   ESCAPE_TO_CALL = 1 << 2,              /* Escapes to a function call.  */
  35   ESCAPE_BAD_CAST = 1 << 3,             /* Cast from pointer to integer */
  36   ESCAPE_TO_RETURN = 1 << 4,            /* Returned from function.  */
  37   ESCAPE_TO_PURE_CONST = 1 << 5,        /* Escapes to a pure or constant
  38                                            function call.  */
  39   ESCAPE_IS_GLOBAL = 1 << 6,            /* Is a global variable.  */
  40   ESCAPE_IS_PARM = 1 << 7,              /* Is an incoming function argument.  */
  41   ESCAPE_UNKNOWN = 1 << 8               /* We believe it escapes for
  42                                            some reason not enumerated
  43                                            above.  */
  44 };
  45
  46
  47 /* The points-to solution.
  48
  49    The points-to solution is a union of pt_vars and the abstract
  50    sets specified by the flags.  */
  51 struct GTY(()) pt_solution
  52 {
  53   /* Nonzero if points-to analysis couldn't determine where this pointer
  54      is pointing to.  */
  55   unsigned int anything : 1;
  56
  57   /* Nonzero if the points-to set includes any global memory.  Note that
  58      even if this is zero pt_vars can still include global variables.  */
  59   unsigned int nonlocal : 1;
  60
  61   /* Nonzero if the points-to set includes any escaped local variable.  */
  62   unsigned int escaped : 1;
  63
  64   /* Nonzero if the points-to set includes 'nothing', the points-to set
  65      includes memory at address NULL.  */
  66   unsigned int null : 1;
  67
  68
  69   /* Nonzero if the pt_vars bitmap includes a global variable.  */
  70   unsigned int vars_contains_global : 1;
  71
  72   /* Set of variables that this pointer may point to.  */
  73   bitmap vars;
  74 };
  75
  76
  77 /* In tree-ssa-alias.c  */
  78 extern enum escape_type is_escape_site (gimple);
  79 extern bool ptr_deref_may_alias_global_p (tree);
  80 extern bool refs_may_alias_p (tree, tree);
  81 extern bool ref_maybe_used_by_stmt_p (gimple, tree);
  82 extern bool stmt_may_clobber_ref_p (gimple, tree);
  83 extern void *walk_non_aliased_vuses (tree, tree,
  84                                      void *(*)(tree, tree, void *), void *);
  85 extern unsigned int walk_aliased_vdefs (tree, tree,
  86                                         bool (*)(tree, tree, void *), void *,
  87                                         bitmap *);
  88 extern struct ptr_info_def *get_ptr_info (tree);
  89 extern void dump_alias_info (FILE *);
  90 extern void debug_alias_info (void);
  91 extern void dump_points_to_info_for (FILE *, tree);
  92 extern void debug_points_to_info_for (tree);
  93 extern void dump_alias_stats (FILE *);
  94
  95
  96 /* In tree-ssa-structalias.c  */
  97 extern unsigned int compute_may_aliases (void);
  98 extern void delete_alias_heapvars (void);
  99 extern bool pt_solution_includes_global (struct pt_solution *);
 100 extern bool pt_solution_includes (struct pt_solution *, const_tree);
 101 extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
 102 extern void pt_solution_reset (struct pt_solution *);
 103 extern void dump_pta_stats (FILE *);
 104
 105
 106 #endif /* TREE_SSA_ALIAS_H  */