gcc/rtl-chkp.c

   1 /* RTL manipulation functions exported by Pointer Bounds Checker.
   2    Copyright (C) 2014 Free Software Foundation, Inc.
   3    Contributed by Ilya Enkovich (ilya.enkovich@intel.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 "expr.h"
  25 #include "target.h"
  26 #include "tree-ssa-alias.h"
  27 #include "internal-fn.h"
  28 #include "is-a.h"
  29 #include "predict.h"
  30 #include "basic-block.h"
  31 #include "tree.h"
  32 #include "gimple-expr.h"
  33 #include "gimple.h"
  34 #include "bitmap.h"
  35 #include "rtl-chkp.h"
  36 #include "tree-chkp.h"
  37 #include "hash-map.h"
  38
  39 static hash_map<tree, rtx> *chkp_rtx_bounds_map;
  40
  41 /* Get bounds rtx associated with NODE via
  42    chkp_set_rtl_bounds call.  */
  43 rtx
  44 chkp_get_rtl_bounds (tree node)
  45 {
  46   rtx *slot;
  47
  48   if (!chkp_rtx_bounds_map)
  49     return NULL_RTX;
  50
  51   slot = chkp_rtx_bounds_map->get (node);
  52   return slot ? *slot : NULL_RTX;
  53 }
  54
  55 /* Associate bounds rtx VAL with NODE.  */
  56 void
  57 chkp_set_rtl_bounds (tree node, rtx val)
  58 {
  59   if (!chkp_rtx_bounds_map)
  60     chkp_rtx_bounds_map = new hash_map<tree, rtx>;
  61
  62   chkp_rtx_bounds_map->put (node, val);
  63 }
  64
  65 /* Reset all bounds stored via chkp_set_rtl_bounds.  */
  66 void
  67 chkp_reset_rtl_bounds ()
  68 {
  69   if (!chkp_rtx_bounds_map)
  70     return;
  71
  72   delete chkp_rtx_bounds_map;
  73   chkp_rtx_bounds_map = NULL;
  74 }
  75
  76 /* Split SLOT identifying slot for function value or
  77    argument into two parts SLOT_VAL and SLOT_BND.
  78    First is the slot for regular value and the other one is
  79    for bounds.  */
  80 void
  81 chkp_split_slot (rtx slot, rtx *slot_val, rtx *slot_bnd)
  82 {
  83   int i;
  84   int val_num = 0;
  85   int bnd_num = 0;
  86   rtx *val_tmps;
  87   rtx *bnd_tmps;
  88
  89   *slot_bnd = 0;
  90
  91   if (!slot
  92       || GET_CODE (slot) != PARALLEL)
  93     {
  94       *slot_val = slot;
  95       return;
  96     }
  97
  98   val_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
  99   bnd_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
 100
 101   for (i = 0; i < XVECLEN (slot, 0); i++)
 102     {
 103       rtx elem = XVECEXP (slot, 0, i);
 104       rtx reg = GET_CODE (elem) == EXPR_LIST ? XEXP (elem, 0) : elem;
 105
 106       if (!reg)
 107         continue;
 108
 109       if (POINTER_BOUNDS_MODE_P (GET_MODE (reg)) || CONST_INT_P (reg))
 110         bnd_tmps[bnd_num++] = elem;
 111       else
 112         val_tmps[val_num++] = elem;
 113     }
 114
 115   gcc_assert (val_num);
 116
 117   if (!bnd_num)
 118     {
 119       *slot_val = slot;
 120       return;
 121     }
 122
 123   if ((GET_CODE (val_tmps[0]) == EXPR_LIST) || (val_num > 1))
 124     *slot_val = gen_rtx_PARALLEL (GET_MODE (slot),
 125                                   gen_rtvec_v (val_num, val_tmps));
 126   else
 127     *slot_val = val_tmps[0];
 128
 129   if ((GET_CODE (bnd_tmps[0]) == EXPR_LIST) || (bnd_num > 1))
 130     *slot_bnd = gen_rtx_PARALLEL (VOIDmode,
 131                                   gen_rtvec_v (bnd_num, bnd_tmps));
 132   else
 133     *slot_bnd = bnd_tmps[0];
 134 }
 135
 136 /* Join previously splitted to VAL and BND rtx for function
 137    value or argument and return it.  */
 138 rtx
 139 chkp_join_splitted_slot (rtx val, rtx bnd)
 140 {
 141   rtx res;
 142   int i, n = 0;
 143
 144   if (!bnd)
 145     return val;
 146
 147   if (GET_CODE (val) == PARALLEL)
 148     n += XVECLEN (val, 0);
 149   else
 150     n++;
 151
 152   if (GET_CODE (bnd) == PARALLEL)
 153     n += XVECLEN (bnd, 0);
 154   else
 155     n++;
 156
 157   res = gen_rtx_PARALLEL (GET_MODE (val), rtvec_alloc (n));
 158
 159   n = 0;
 160
 161   if (GET_CODE (val) == PARALLEL)
 162     for (i = 0; i < XVECLEN (val, 0); i++)
 163       XVECEXP (res, 0, n++) = XVECEXP (val, 0, i);
 164   else
 165     XVECEXP (res, 0, n++) = val;
 166
 167   if (GET_CODE (bnd) == PARALLEL)
 168     for (i = 0; i < XVECLEN (bnd, 0); i++)
 169       XVECEXP (res, 0, n++) = XVECEXP (bnd, 0, i);
 170   else
 171     XVECEXP (res, 0, n++) = bnd;
 172
 173   return res;
 174 }
 175
 176 /* If PAR is PARALLEL holding registers then transform
 177    it into PARALLEL holding EXPR_LISTs of those regs
 178    and zero constant (similar to how function value
 179    on multiple registers looks like).  */
 180 void
 181 chkp_put_regs_to_expr_list (rtx par)
 182 {
 183   int n;
 184
 185   if (GET_CODE (par) != PARALLEL
 186       || GET_CODE (XVECEXP (par, 0, 0)) == EXPR_LIST)
 187     return;
 188
 189   for (n = 0; n < XVECLEN (par, 0); n++)
 190     XVECEXP (par, 0, n) = gen_rtx_EXPR_LIST (VOIDmode,
 191                                              XVECEXP (par, 0, n),
 192                                              const0_rtx);
 193 }
 194
 195 /*  Search rtx PAR describing function return value for an
 196     item related to value at offset OFFS and return it.
 197     Return NULL if item was not found.  */
 198 rtx
 199 chkp_get_value_with_offs (rtx par, rtx offs)
 200 {
 201   int n;
 202
 203   gcc_assert (GET_CODE (par) == PARALLEL);
 204
 205   for (n = 0; n < XVECLEN (par, 0); n++)
 206     {
 207       rtx par_offs = XEXP (XVECEXP (par, 0, n), 1);
 208       if (INTVAL (offs) == INTVAL (par_offs))
 209         return XEXP (XVECEXP (par, 0, n), 0);
 210     }
 211
 212   return NULL;
 213 }
 214
 215 /* Emit instructions to store BOUNDS for pointer VALUE
 216    stored in MEM.
 217    Function is used by expand to pass bounds for args
 218    passed on stack.  */
 219 void
 220 chkp_emit_bounds_store (rtx bounds, rtx value, rtx mem)
 221 {
 222   gcc_assert (MEM_P (mem));
 223
 224   if (REG_P (bounds) || CONST_INT_P (bounds))
 225     {
 226       rtx ptr;
 227
 228       if (REG_P (value))
 229         ptr = value;
 230       else
 231         {
 232           rtx slot = adjust_address (value, Pmode, 0);
 233           ptr = gen_reg_rtx (Pmode);
 234           emit_move_insn (ptr, slot);
 235         }
 236
 237       if (CONST_INT_P (bounds))
 238         bounds = targetm.calls.load_bounds_for_arg (value, ptr, bounds);
 239
 240       targetm.calls.store_bounds_for_arg (ptr, mem,
 241                                           bounds, NULL);
 242     }
 243   else
 244     {
 245       int i;
 246
 247       gcc_assert (GET_CODE (bounds) == PARALLEL);
 248       gcc_assert (GET_CODE (value) == PARALLEL || MEM_P (value) || REG_P (value));
 249
 250       for (i = 0; i < XVECLEN (bounds, 0); i++)
 251         {
 252           rtx reg = XEXP (XVECEXP (bounds, 0, i), 0);
 253           rtx offs = XEXP (XVECEXP (bounds, 0, i), 1);
 254           rtx slot = adjust_address (mem, Pmode, INTVAL (offs));
 255           rtx ptr;
 256
 257           if (GET_CODE (value) == PARALLEL)
 258             ptr = chkp_get_value_with_offs (value, offs);
 259           else if (MEM_P (value))
 260             {
 261               rtx tmp = adjust_address (value, Pmode, INTVAL (offs));
 262               ptr = gen_reg_rtx (Pmode);
 263               emit_move_insn (ptr, tmp);
 264             }
 265           else
 266             ptr = gen_rtx_SUBREG (Pmode, value, INTVAL (offs));
 267
 268           targetm.calls.store_bounds_for_arg (ptr, slot, reg, NULL);
 269         }
 270     }
 271 }
 272
 273 /* Emit code to copy bounds for structure VALUE of type TYPE
 274    copied to SLOT.  */
 275 void
 276 chkp_copy_bounds_for_stack_parm (rtx slot, rtx value, tree type)
 277 {
 278   bitmap have_bound;
 279   bitmap_iterator bi;
 280   unsigned i;
 281   rtx tmp = NULL, bnd;
 282
 283   gcc_assert (TYPE_SIZE (type));
 284   gcc_assert (MEM_P (value));
 285   gcc_assert (MEM_P (slot));
 286   gcc_assert (RECORD_OR_UNION_TYPE_P (type));
 287
 288   bitmap_obstack_initialize (NULL);
 289   have_bound = BITMAP_ALLOC (NULL);
 290   chkp_find_bound_slots (type, have_bound);
 291
 292   EXECUTE_IF_SET_IN_BITMAP (have_bound, 0, i, bi)
 293     {
 294       rtx ptr = adjust_address (value, Pmode, i * POINTER_SIZE / 8);
 295       rtx to = adjust_address (slot, Pmode, i * POINTER_SIZE / 8);
 296
 297       if (!tmp)
 298         tmp = gen_reg_rtx (Pmode);
 299
 300       emit_move_insn (tmp, ptr);
 301       bnd = targetm.calls.load_bounds_for_arg (ptr, tmp, NULL);
 302       targetm.calls.store_bounds_for_arg (tmp, to, bnd, NULL);
 303     }
 304
 305   BITMAP_FREE (have_bound);
 306   bitmap_obstack_release (NULL);
 307 }