gcc/adjust-alignment.cc

   1 /* Adjust alignment for local variable.
   2    Copyright (C) 2020-2023 Free Software Foundation, Inc.
   3    Contributed by Kito Cheng <kito.cheng@sifive.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 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "backend.h"
  25 #include "target.h"
  26 #include "tree.h"
  27 #include "tree-pass.h"
  28 #include "memmodel.h"
  29 #include "tm_p.h"
  30
  31 namespace {
  32
  33 const pass_data pass_data_adjust_alignment =
  34 {
  35   GIMPLE_PASS, /* type */
  36   "adjust_alignment", /* name */
  37   OPTGROUP_NONE, /* optinfo_flags */
  38   TV_NONE, /* tv_id */
  39   0, /* properties_required */
  40   0, /* properties_provided */
  41   0, /* properties_destroyed */
  42   0, /* todo_flags_start */
  43   0, /* todo_flags_finish */
  44 };
  45
  46 class pass_adjust_alignment : public gimple_opt_pass
  47 {
  48 public:
  49   pass_adjust_alignment (gcc::context *ctxt)
  50     : gimple_opt_pass (pass_data_adjust_alignment, ctxt)
  51   {}
  52
  53   unsigned int execute (function *) final override;
  54 }; // class pass_adjust_alignment
  55
  56 } // anon namespace
  57
  58 /* Entry point to adjust_alignment pass.  */
  59 unsigned int
  60 pass_adjust_alignment::execute (function *fun)
  61 {
  62   size_t i;
  63   tree var;
  64
  65   FOR_EACH_LOCAL_DECL (fun, i, var)
  66     {
  67       /* Don't adjust aligment for static local var and hard register var.  */
  68       if (is_global_var (var) || DECL_HARD_REGISTER (var))
  69         continue;
  70
  71       unsigned align = LOCAL_DECL_ALIGNMENT (var);
  72
  73       /* Make sure alignment only increase.  */
  74       gcc_assert (align >= DECL_ALIGN (var));
  75
  76       SET_DECL_ALIGN (var, align);
  77     }
  78   return 0;
  79 }
  80
  81 gimple_opt_pass *
  82 make_pass_adjust_alignment (gcc::context *ctxt)
  83 {
  84   return new pass_adjust_alignment (ctxt);
  85 }