gcc/rtl-chkp.c

   1 /* RTL manipulation functions exported by Pointer Bounds Checker.
   2    Copyright (C) 2014-2017 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 "backend.h"
  25 #include "target.h"
  26 #include "rtl.h"
  27 #include "tree.h"
  28 #include "memmodel.h"
  29 #include "emit-rtl.h"
  30 #include "expr.h"
  31 #include "rtl-chkp.h"
  32 #include "tree-chkp.h"
  33
  34 static hash_map<tree, rtx> *chkp_rtx_bounds_map;
  35
  36 /* Get bounds rtx associated with NODE via
  37    chkp_set_rtl_bounds call.  */
  38 rtx
  39 chkp_get_rtl_bounds (tree node)
  40 {
  41   rtx *slot;
  42
  43   if (!chkp_rtx_bounds_map)
  44     return NULL_RTX;
  45
  46   slot = chkp_rtx_bounds_map->get (node);
  47   return slot ? *slot : NULL_RTX;
  48 }
  49
  50 /* Associate bounds rtx VAL with NODE.  */
  51 void
  52 chkp_set_rtl_bounds (tree node, rtx val)
  53 {
  54   if (!chkp_rtx_bounds_map)
  55     chkp_rtx_bounds_map = new hash_map<tree, rtx>;
  56
  57   chkp_rtx_bounds_map->put (node, val);
  58 }
  59
  60 /* Reset all bounds stored via chkp_set_rtl_bounds.  */
  61 void
  62 chkp_reset_rtl_bounds ()
  63 {
  64   if (!chkp_rtx_bounds_map)
  65     return;
  66
  67   delete chkp_rtx_bounds_map;
  68   chkp_rtx_bounds_map = NULL;
  69 }
  70
  71 /* Split SLOT identifying slot for function value or
  72    argument into two parts SLOT_VAL and SLOT_BND.
  73    First is the slot for regular value and the other one is
  74    for bounds.  */
  75 void
  76 chkp_split_slot (rtx slot, rtx *slot_val, rtx *slot_bnd)
  77 {
  78   int i;
  79   int val_num = 0;
  80   int bnd_num = 0;
  81   rtx *val_tmps;
  82   rtx *bnd_tmps;
  83
  84   *slot_bnd = 0;
  85
  86   if (!slot
  87       || GET_CODE (slot) != PARALLEL)
  88     {
  89       *slot_val = slot;
  90       return;
  91     }
  92
  93   val_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
  94   bnd_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
  95
  96   for (i = 0; i < XVECLEN (slot, 0); i++)
  97     {
  98       rtx elem = XVECEXP (slot, 0, i);
  99       rtx reg = GET_CODE (elem) == EXPR_LIST ? XEXP (elem, 0) : elem;
 100
 101       if (!reg)
 102         continue;
 103
 104       if (POINTER_BOUNDS_MODE_P (GET_MODE (reg)) || CONST_INT_P (reg))
 105         bnd_tmps[bnd_num++] = elem;
 106       else
 107         val_tmps[val_num++] = elem;
 108     }
 109
 110   gcc_assert (val_num);
 111
 112   if (!bnd_num)
 113     {
 114       *slot_val = slot;
 115       return;
 116     }
 117
 118   if ((GET_CODE (val_tmps[0]) == EXPR_LIST) || (val_num > 1))
 119     *slot_val = gen_rtx_PARALLEL (GET_MODE (slot),
 120                                   gen_rtvec_v (val_num, val_tmps));
 121   else
 122     *slot_val = val_tmps[0];
 123
 124   if ((GET_CODE (bnd_tmps[0]) == EXPR_LIST) || (bnd_num > 1))
 125     *slot_bnd = gen_rtx_PARALLEL (VOIDmode,
 126                                   gen_rtvec_v (bnd_num, bnd_tmps));
 127   else
 128     *slot_bnd = bnd_tmps[0];
 129 }
 130
 131 /* Join previously splitted to VAL and BND rtx for function
 132    value or argument and return it.  */
 133 rtx
 134 chkp_join_splitted_slot (rtx val, rtx bnd)
 135 {
 136   rtx res;
 137   int i, n = 0;
 138
 139   if (!bnd)
 140     return val;
 141
 142   if (GET_CODE (val) == PARALLEL)
 143     n += XVECLEN (val, 0);
 144   else
 145     n++;
 146
 147   if (GET_CODE (bnd) == PARALLEL)
 148     n += XVECLEN (bnd, 0);
 149   else
 150     n++;
 151
 152   res = gen_rtx_PARALLEL (GET_MODE (val), rtvec_alloc (n));
 153
 154   n = 0;
 155
 156   if (GET_CODE (val) == PARALLEL)
 157     for (i = 0; i < XVECLEN (val, 0); i++)
 158       XVECEXP (res, 0, n++) = XVECEXP (val, 0, i);
 159   else
 160     XVECEXP (res, 0, n++) = val;
 161
 162   if (GET_CODE (bnd) == PARALLEL)
 163     for (i = 0; i < XVECLEN (bnd, 0); i++)
 164       XVECEXP (res, 0, n++) = XVECEXP (bnd, 0, i);
 165   else
 166     XVECEXP (res, 0, n++) = bnd;
 167
 168   return res;
 169 }
 170
 171 /* If PAR is PARALLEL holding registers then transform
 172    it into PARALLEL holding EXPR_LISTs of those regs
 173    and zero constant (similar to how function value
 174    on multiple registers looks like).  */
 175 void
 176 chkp_put_regs_to_expr_list (rtx par)
 177 {
 178   int n;
 179
 180   if (GET_CODE (par) != PARALLEL
 181       || GET_CODE (XVECEXP (par, 0, 0)) == EXPR_LIST)
 182     return;
 183
 184   for (n = 0; n < XVECLEN (par, 0); n++)
 185     XVECEXP (par, 0, n) = gen_rtx_EXPR_LIST (VOIDmode,
 186                                              XVECEXP (par, 0, n),
 187                                              const0_rtx);
 188 }
 189
 190 /*  Search rtx PAR describing function return value for an
 191     item related to value at offset OFFS and return it.
 192     Return NULL if item was not found.  */
 193 rtx
 194 chkp_get_value_with_offs (rtx par, rtx offs)
 195 {
 196   int n;
 197
 198   gcc_assert (GET_CODE (par) == PARALLEL);
 199
 200   for (n = 0; n < XVECLEN (par, 0); n++)
 201     {
 202       rtx par_offs = XEXP (XVECEXP (par, 0, n), 1);
 203       if (INTVAL (offs) == INTVAL (par_offs))
 204         return XEXP (XVECEXP (par, 0, n), 0);
 205     }
 206
 207   return NULL;
 208 }
 209
 210 /* Emit instructions to store BOUNDS for pointer VALUE
 211    stored in MEM.
 212    Function is used by expand to pass bounds for args
 213    passed on stack.  */
 214 void
 215 chkp_emit_bounds_store (rtx bounds, rtx value, rtx mem)
 216 {
 217   gcc_assert (MEM_P (mem));
 218
 219   if (REG_P (bounds) || CONST_INT_P (bounds))
 220     {
 221       rtx ptr;
 222
 223       if (REG_P (value))
 224         ptr = value;
 225       else
 226         {
 227           rtx slot = adjust_address (value, Pmode, 0);
 228           ptr = gen_reg_rtx (Pmode);
 229           emit_move_insn (ptr, slot);
 230         }
 231
 232       if (CONST_INT_P (bounds))
 233         bounds = targetm.calls.load_bounds_for_arg (value, ptr, bounds);
 234
 235       targetm.calls.store_bounds_for_arg (ptr, mem,
 236                                           bounds, NULL);
 237     }
 238   else
 239     {
 240       int i;
 241
 242       gcc_assert (GET_CODE (bounds) == PARALLEL);
 243       gcc_assert (GET_CODE (value) == PARALLEL || MEM_P (value) || REG_P (value));
 244
 245       for (i = 0; i < XVECLEN (bounds, 0); i++)
 246         {
 247           rtx reg = XEXP (XVECEXP (bounds, 0, i), 0);
 248           rtx offs = XEXP (XVECEXP (bounds, 0, i), 1);
 249           rtx slot = adjust_address (mem, Pmode, INTVAL (offs));
 250           rtx ptr;
 251
 252           if (GET_CODE (value) == PARALLEL)
 253             ptr = chkp_get_value_with_offs (value, offs);
 254           else if (MEM_P (value))
 255             {
 256               rtx tmp = adjust_address (value, Pmode, INTVAL (offs));
 257               ptr = gen_reg_rtx (Pmode);
 258               emit_move_insn (ptr, tmp);
 259             }
 260           else
 261             ptr = gen_rtx_SUBREG (Pmode, value, INTVAL (offs));
 262
 263           targetm.calls.store_bounds_for_arg (ptr, slot, reg, NULL);
 264         }
 265     }
 266 }
 267
 268 /* Emit code to copy bounds for structure VALUE of type TYPE
 269    copied to SLOT.  */
 270 void
 271 chkp_copy_bounds_for_stack_parm (rtx slot, rtx value, tree type)
 272 {
 273   bitmap have_bound;
 274   bitmap_iterator bi;
 275   unsigned i;
 276   rtx tmp = NULL, bnd;
 277
 278   gcc_assert (TYPE_SIZE (type));
 279   gcc_assert (MEM_P (value));
 280   gcc_assert (MEM_P (slot));
 281   gcc_assert (RECORD_OR_UNION_TYPE_P (type));
 282
 283   bitmap_obstack_initialize (NULL);
 284   have_bound = BITMAP_ALLOC (NULL);
 285   chkp_find_bound_slots (type, have_bound);
 286
 287   EXECUTE_IF_SET_IN_BITMAP (have_bound, 0, i, bi)
 288     {
 289       rtx ptr = adjust_address (value, Pmode, i * POINTER_SIZE / 8);
 290       rtx to = adjust_address (slot, Pmode, i * POINTER_SIZE / 8);
 291
 292       if (!tmp)
 293         tmp = gen_reg_rtx (Pmode);
 294
 295       emit_move_insn (tmp, ptr);
 296       bnd = targetm.calls.load_bounds_for_arg (ptr, tmp, NULL);
 297       targetm.calls.store_bounds_for_arg (tmp, to, bnd, NULL);
 298     }
 299
 300   BITMAP_FREE (have_bound);
 301   bitmap_obstack_release (NULL);
 302 }