gcc/rtl-chkp.c

   1 /* RTL manipulation functions exported by Pointer Bounds Checker.
   2    Copyright (C) 2014-2016 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 "emit-rtl.h"
  29 #include "expr.h"
  30 #include "rtl-chkp.h"
  31 #include "tree-chkp.h"
  32
  33 static hash_map<tree, rtx> *chkp_rtx_bounds_map;
  34
  35 /* Get bounds rtx associated with NODE via
  36    chkp_set_rtl_bounds call.  */
  37 rtx
  38 chkp_get_rtl_bounds (tree node)
  39 {
  40   rtx *slot;
  41
  42   if (!chkp_rtx_bounds_map)
  43     return NULL_RTX;
  44
  45   slot = chkp_rtx_bounds_map->get (node);
  46   return slot ? *slot : NULL_RTX;
  47 }
  48
  49 /* Associate bounds rtx VAL with NODE.  */
  50 void
  51 chkp_set_rtl_bounds (tree node, rtx val)
  52 {
  53   if (!chkp_rtx_bounds_map)
  54     chkp_rtx_bounds_map = new hash_map<tree, rtx>;
  55
  56   chkp_rtx_bounds_map->put (node, val);
  57 }
  58
  59 /* Reset all bounds stored via chkp_set_rtl_bounds.  */
  60 void
  61 chkp_reset_rtl_bounds ()
  62 {
  63   if (!chkp_rtx_bounds_map)
  64     return;
  65
  66   delete chkp_rtx_bounds_map;
  67   chkp_rtx_bounds_map = NULL;
  68 }
  69
  70 /* Split SLOT identifying slot for function value or
  71    argument into two parts SLOT_VAL and SLOT_BND.
  72    First is the slot for regular value and the other one is
  73    for bounds.  */
  74 void
  75 chkp_split_slot (rtx slot, rtx *slot_val, rtx *slot_bnd)
  76 {
  77   int i;
  78   int val_num = 0;
  79   int bnd_num = 0;
  80   rtx *val_tmps;
  81   rtx *bnd_tmps;
  82
  83   *slot_bnd = 0;
  84
  85   if (!slot
  86       || GET_CODE (slot) != PARALLEL)
  87     {
  88       *slot_val = slot;
  89       return;
  90     }
  91
  92   val_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
  93   bnd_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
  94
  95   for (i = 0; i < XVECLEN (slot, 0); i++)
  96     {
  97       rtx elem = XVECEXP (slot, 0, i);
  98       rtx reg = GET_CODE (elem) == EXPR_LIST ? XEXP (elem, 0) : elem;
  99
 100       if (!reg)
 101         continue;
 102
 103       if (POINTER_BOUNDS_MODE_P (GET_MODE (reg)) || CONST_INT_P (reg))
 104         bnd_tmps[bnd_num++] = elem;
 105       else
 106         val_tmps[val_num++] = elem;
 107     }
 108
 109   gcc_assert (val_num);
 110
 111   if (!bnd_num)
 112     {
 113       *slot_val = slot;
 114       return;
 115     }
 116
 117   if ((GET_CODE (val_tmps[0]) == EXPR_LIST) || (val_num > 1))
 118     *slot_val = gen_rtx_PARALLEL (GET_MODE (slot),
 119                                   gen_rtvec_v (val_num, val_tmps));
 120   else
 121     *slot_val = val_tmps[0];
 122
 123   if ((GET_CODE (bnd_tmps[0]) == EXPR_LIST) || (bnd_num > 1))
 124     *slot_bnd = gen_rtx_PARALLEL (VOIDmode,
 125                                   gen_rtvec_v (bnd_num, bnd_tmps));
 126   else
 127     *slot_bnd = bnd_tmps[0];
 128 }
 129
 130 /* Join previously splitted to VAL and BND rtx for function
 131    value or argument and return it.  */
 132 rtx
 133 chkp_join_splitted_slot (rtx val, rtx bnd)
 134 {
 135   rtx res;
 136   int i, n = 0;
 137
 138   if (!bnd)
 139     return val;
 140
 141   if (GET_CODE (val) == PARALLEL)
 142     n += XVECLEN (val, 0);
 143   else
 144     n++;
 145
 146   if (GET_CODE (bnd) == PARALLEL)
 147     n += XVECLEN (bnd, 0);
 148   else
 149     n++;
 150
 151   res = gen_rtx_PARALLEL (GET_MODE (val), rtvec_alloc (n));
 152
 153   n = 0;
 154
 155   if (GET_CODE (val) == PARALLEL)
 156     for (i = 0; i < XVECLEN (val, 0); i++)
 157       XVECEXP (res, 0, n++) = XVECEXP (val, 0, i);
 158   else
 159     XVECEXP (res, 0, n++) = val;
 160
 161   if (GET_CODE (bnd) == PARALLEL)
 162     for (i = 0; i < XVECLEN (bnd, 0); i++)
 163       XVECEXP (res, 0, n++) = XVECEXP (bnd, 0, i);
 164   else
 165     XVECEXP (res, 0, n++) = bnd;
 166
 167   return res;
 168 }
 169
 170 /* If PAR is PARALLEL holding registers then transform
 171    it into PARALLEL holding EXPR_LISTs of those regs
 172    and zero constant (similar to how function value
 173    on multiple registers looks like).  */
 174 void
 175 chkp_put_regs_to_expr_list (rtx par)
 176 {
 177   int n;
 178
 179   if (GET_CODE (par) != PARALLEL
 180       || GET_CODE (XVECEXP (par, 0, 0)) == EXPR_LIST)
 181     return;
 182
 183   for (n = 0; n < XVECLEN (par, 0); n++)
 184     XVECEXP (par, 0, n) = gen_rtx_EXPR_LIST (VOIDmode,
 185                                              XVECEXP (par, 0, n),
 186                                              const0_rtx);
 187 }
 188
 189 /*  Search rtx PAR describing function return value for an
 190     item related to value at offset OFFS and return it.
 191     Return NULL if item was not found.  */
 192 rtx
 193 chkp_get_value_with_offs (rtx par, rtx offs)
 194 {
 195   int n;
 196
 197   gcc_assert (GET_CODE (par) == PARALLEL);
 198
 199   for (n = 0; n < XVECLEN (par, 0); n++)
 200     {
 201       rtx par_offs = XEXP (XVECEXP (par, 0, n), 1);
 202       if (INTVAL (offs) == INTVAL (par_offs))
 203         return XEXP (XVECEXP (par, 0, n), 0);
 204     }
 205
 206   return NULL;
 207 }
 208
 209 /* Emit instructions to store BOUNDS for pointer VALUE
 210    stored in MEM.
 211    Function is used by expand to pass bounds for args
 212    passed on stack.  */
 213 void
 214 chkp_emit_bounds_store (rtx bounds, rtx value, rtx mem)
 215 {
 216   gcc_assert (MEM_P (mem));
 217
 218   if (REG_P (bounds) || CONST_INT_P (bounds))
 219     {
 220       rtx ptr;
 221
 222       if (REG_P (value))
 223         ptr = value;
 224       else
 225         {
 226           rtx slot = adjust_address (value, Pmode, 0);
 227           ptr = gen_reg_rtx (Pmode);
 228           emit_move_insn (ptr, slot);
 229         }
 230
 231       if (CONST_INT_P (bounds))
 232         bounds = targetm.calls.load_bounds_for_arg (value, ptr, bounds);
 233
 234       targetm.calls.store_bounds_for_arg (ptr, mem,
 235                                           bounds, NULL);
 236     }
 237   else
 238     {
 239       int i;
 240
 241       gcc_assert (GET_CODE (bounds) == PARALLEL);
 242       gcc_assert (GET_CODE (value) == PARALLEL || MEM_P (value) || REG_P (value));
 243
 244       for (i = 0; i < XVECLEN (bounds, 0); i++)
 245         {
 246           rtx reg = XEXP (XVECEXP (bounds, 0, i), 0);
 247           rtx offs = XEXP (XVECEXP (bounds, 0, i), 1);
 248           rtx slot = adjust_address (mem, Pmode, INTVAL (offs));
 249           rtx ptr;
 250
 251           if (GET_CODE (value) == PARALLEL)
 252             ptr = chkp_get_value_with_offs (value, offs);
 253           else if (MEM_P (value))
 254             {
 255               rtx tmp = adjust_address (value, Pmode, INTVAL (offs));
 256               ptr = gen_reg_rtx (Pmode);
 257               emit_move_insn (ptr, tmp);
 258             }
 259           else
 260             ptr = gen_rtx_SUBREG (Pmode, value, INTVAL (offs));
 261
 262           targetm.calls.store_bounds_for_arg (ptr, slot, reg, NULL);
 263         }
 264     }
 265 }
 266
 267 /* Emit code to copy bounds for structure VALUE of type TYPE
 268    copied to SLOT.  */
 269 void
 270 chkp_copy_bounds_for_stack_parm (rtx slot, rtx value, tree type)
 271 {
 272   bitmap have_bound;
 273   bitmap_iterator bi;
 274   unsigned i;
 275   rtx tmp = NULL, bnd;
 276
 277   gcc_assert (TYPE_SIZE (type));
 278   gcc_assert (MEM_P (value));
 279   gcc_assert (MEM_P (slot));
 280   gcc_assert (RECORD_OR_UNION_TYPE_P (type));
 281
 282   bitmap_obstack_initialize (NULL);
 283   have_bound = BITMAP_ALLOC (NULL);
 284   chkp_find_bound_slots (type, have_bound);
 285
 286   EXECUTE_IF_SET_IN_BITMAP (have_bound, 0, i, bi)
 287     {
 288       rtx ptr = adjust_address (value, Pmode, i * POINTER_SIZE / 8);
 289       rtx to = adjust_address (slot, Pmode, i * POINTER_SIZE / 8);
 290
 291       if (!tmp)
 292         tmp = gen_reg_rtx (Pmode);
 293
 294       emit_move_insn (tmp, ptr);
 295       bnd = targetm.calls.load_bounds_for_arg (ptr, tmp, NULL);
 296       targetm.calls.store_bounds_for_arg (tmp, to, bnd, NULL);
 297     }
 298
 299   BITMAP_FREE (have_bound);
 300   bitmap_obstack_release (NULL);
 301 }