gcc/value-pointer-equiv.h

   1 /* Header file for the context-aware pointer equivalence tracker.
   2    Copyright (C) 2020-2021 Free Software Foundation, Inc.
   3    Contributed by Aldy Hernandez <aldyh@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  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 GCC_VALUE_POINTER_EQUIV_H
  22 #define GCC_VALUE_POINTER_EQUIV_H
  23
  24 // Simple context-aware pointer equivalency analyzer that returns what
  25 // a pointer SSA name is equivalent to at a given point during a walk
  26 // of the IL.
  27 //
  28 // Note that global equivalency take priority over conditional
  29 // equivalency.  That is, p = &q takes priority over a later p == &t.
  30 //
  31 // This class is meant to be called during a DOM walk.
  32
  33 class pointer_equiv_analyzer
  34 {
  35 public:
  36   pointer_equiv_analyzer (gimple_ranger *r);
  37   ~pointer_equiv_analyzer ();
  38   void enter (basic_block);
  39   void leave (basic_block);
  40   void visit_stmt (gimple *stmt);
  41   tree get_equiv (tree ssa);
  42
  43 private:
  44   void visit_edge (edge e);
  45   tree get_equiv_expr (tree_code code, tree expr);
  46   void set_global_equiv (tree ssa, tree pointee);
  47   void set_cond_equiv (tree ssa, tree pointee);
  48
  49   gimple_ranger *m_ranger;
  50   // Global pointer equivalency indexed by SSA_NAME_VERSION.
  51   auto_vec<tree> m_global_points;
  52   // Conditional pointer equivalency.
  53   class ssa_equiv_stack *m_cond_points;
  54 };
  55
  56 inline bool
  57 supported_pointer_equiv_p (tree expr)
  58 {
  59   return TREE_CODE (expr) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (expr));
  60 }
  61
  62 #endif // GCC_VALUE_POINTER_EQUIV_H