1  /* Alignment-related classes.
       2     Copyright (C) 2018-2023 Free Software Foundation, Inc.
       3  
       4  This file is part of GCC.
       5  
       6  GCC is free software; you can redistribute it and/or modify it under
       7  the terms of the GNU General Public License as published by the Free
       8  Software Foundation; either version 3, or (at your option) any later
       9  version.
      10  
      11  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      12  WARRANTY; without even the implied warranty of MERCHANTABILITY or
      13  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      14  for more details.
      15  
      16  You should have received a copy of the GNU General Public License
      17  along with GCC; see the file COPYING3.  If not see
      18  <http://www.gnu.org/licenses/>.  */
      19  
      20  /* Align flags tuple with alignment in log form and with a maximum skip.  */
      21  
      22  struct align_flags_tuple
      23  {
      24    /* Values of the -falign-* flags: how much to align labels in code.
      25       log is "align to 2^log" (so 0 means no alignment).
      26       maxskip is the maximum allowed amount of padding to insert.  */
      27    int log;
      28    int maxskip;
      29  
      30    /* Normalize filled values so that maxskip is not bigger than 1 << log.  */
      31    void normalize ()
      32    {
      33      int n = (1 << log);
      34      if (maxskip > n)
      35        maxskip = n - 1;
      36    }
      37  
      38    /* Return original value of an alignment flag.  */
      39    int get_value ()
      40    {
      41      return maxskip + 1;
      42    }
      43  };
      44  
      45  /* Alignment flags is structure used as value of -align-* options.
      46     It's used in target-dependant code.  */
      47  
      48  class align_flags
      49  {
      50  public:
      51    /* Default constructor.  */
      52    align_flags (int log0 = 0, int maxskip0 = 0, int log1 = 0, int maxskip1 = 0)
      53    {
      54      levels[0].log = log0;
      55      levels[0].maxskip = maxskip0;
      56      levels[1].log = log1;
      57      levels[1].maxskip = maxskip1;
      58      normalize ();
      59    }
      60  
      61    /* Normalize both components of align_flags.  */
      62    void normalize ()
      63    {
      64      for (unsigned i = 0; i < 2; i++)
      65        levels[i].normalize ();
      66    }
      67  
      68    /* Get alignment that is common bigger alignment of alignments F0 and F1.  */
      69    static align_flags max (const align_flags f0, const align_flags f1)
      70      {
      71        int log0 = MAX (f0.levels[0].log, f1.levels[0].log);
      72        int maxskip0 = MAX (f0.levels[0].maxskip, f1.levels[0].maxskip);
      73        int log1 = MAX (f0.levels[1].log, f1.levels[1].log);
      74        int maxskip1 = MAX (f0.levels[1].maxskip, f1.levels[1].maxskip);
      75        return align_flags (log0, maxskip0, log1, maxskip1);
      76      }
      77  
      78    align_flags_tuple levels[2];
      79  };
      80  
      81  /* Define maximum supported code alignment.  */
      82  #define MAX_CODE_ALIGN 16
      83  #define MAX_CODE_ALIGN_VALUE (1 << MAX_CODE_ALIGN)