1  /* Header file for the context-aware pointer equivalence tracker.
       2     Copyright (C) 2020-2023 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