gcc/rtl-chkp.c

   1 /* RTL manipulation functions exported by Pointer Bounds Checker.
   2    Copyright (C) 2014-2015 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 "symtab.h"
  25 #include "hashtab.h"
  26 #include "hash-set.h"
  27 #include "vec.h"
  28 #include "tm.h"
  29 #include "hard-reg-set.h"
  30 #include "input.h"
  31 #include "function.h"
  32 #include "rtl.h"
  33 #include "flags.h"
  34 #include "statistics.h"
  35 #include "alias.h"
  36 #include "inchash.h"
  37 #include "tree.h"
  38 #include "insn-config.h"
  39 #include "expmed.h"
  40 #include "dojump.h"
  41 #include "explow.h"
  42 #include "calls.h"
  43 #include "emit-rtl.h"
  44 #include "varasm.h"
  45 #include "stmt.h"
  46 #include "expr.h"
  47 #include "target.h"
  48 #include "tree-ssa-alias.h"
  49 #include "internal-fn.h"
  50 #include "is-a.h"
  51 #include "predict.h"
  52 #include "basic-block.h"
  53 #include "fold-const.h"
  54 #include "gimple-expr.h"
  55 #include "gimple.h"
  56 #include "bitmap.h"
  57 #include "rtl-chkp.h"
  58 #include "tree-chkp.h"
  59 #include "hash-map.h"
  60
  61 static hash_map<tree, rtx> *chkp_rtx_bounds_map;
  62
  63 /* Get bounds rtx associated with NODE via
  64    chkp_set_rtl_bounds call.  */
  65 rtx
  66 chkp_get_rtl_bounds (tree node)
  67 {
  68   rtx *slot;
  69
  70   if (!chkp_rtx_bounds_map)
  71     return NULL_RTX;
  72
  73   slot = chkp_rtx_bounds_map->get (node);
  74   return slot ? *slot : NULL_RTX;
  75 }
  76
  77 /* Associate bounds rtx VAL with NODE.  */
  78 void
  79 chkp_set_rtl_bounds (tree node, rtx val)
  80 {
  81   if (!chkp_rtx_bounds_map)
  82     chkp_rtx_bounds_map = new hash_map<tree, rtx>;
  83
  84   chkp_rtx_bounds_map->put (node, val);
  85 }
  86
  87 /* Reset all bounds stored via chkp_set_rtl_bounds.  */
  88 void
  89 chkp_reset_rtl_bounds ()
  90 {
  91   if (!chkp_rtx_bounds_map)
  92     return;
  93
  94   delete chkp_rtx_bounds_map;
  95   chkp_rtx_bounds_map = NULL;
  96 }
  97
  98 /* Split SLOT identifying slot for function value or
  99    argument into two parts SLOT_VAL and SLOT_BND.
 100    First is the slot for regular value and the other one is
 101    for bounds.  */
 102 void
 103 chkp_split_slot (rtx slot, rtx *slot_val, rtx *slot_bnd)
 104 {
 105   int i;
 106   int val_num = 0;
 107   int bnd_num = 0;
 108   rtx *val_tmps;
 109   rtx *bnd_tmps;
 110
 111   *slot_bnd = 0;
 112
 113   if (!slot
 114       || GET_CODE (slot) != PARALLEL)
 115     {
 116       *slot_val = slot;
 117       return;
 118     }
 119
 120   val_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
 121   bnd_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
 122
 123   for (i = 0; i < XVECLEN (slot, 0); i++)
 124     {
 125       rtx elem = XVECEXP (slot, 0, i);
 126       rtx reg = GET_CODE (elem) == EXPR_LIST ? XEXP (elem, 0) : elem;
 127
 128       if (!reg)
 129         continue;
 130
 131       if (POINTER_BOUNDS_MODE_P (GET_MODE (reg)) || CONST_INT_P (reg))
 132         bnd_tmps[bnd_num++] = elem;
 133       else
 134         val_tmps[val_num++] = elem;
 135     }
 136
 137   gcc_assert (val_num);
 138
 139   if (!bnd_num)
 140     {
 141       *slot_val = slot;
 142       return;
 143     }
 144
 145   if ((GET_CODE (val_tmps[0]) == EXPR_LIST) || (val_num > 1))
 146     *slot_val = gen_rtx_PARALLEL (GET_MODE (slot),
 147                                   gen_rtvec_v (val_num, val_tmps));
 148   else
 149     *slot_val = val_tmps[0];
 150
 151   if ((GET_CODE (bnd_tmps[0]) == EXPR_LIST) || (bnd_num > 1))
 152     *slot_bnd = gen_rtx_PARALLEL (VOIDmode,
 153                                   gen_rtvec_v (bnd_num, bnd_tmps));
 154   else
 155     *slot_bnd = bnd_tmps[0];
 156 }
 157
 158 /* Join previously splitted to VAL and BND rtx for function
 159    value or argument and return it.  */
 160 rtx
 161 chkp_join_splitted_slot (rtx val, rtx bnd)
 162 {
 163   rtx res;
 164   int i, n = 0;
 165
 166   if (!bnd)
 167     return val;
 168
 169   if (GET_CODE (val) == PARALLEL)
 170     n += XVECLEN (val, 0);
 171   else
 172     n++;
 173
 174   if (GET_CODE (bnd) == PARALLEL)
 175     n += XVECLEN (bnd, 0);
 176   else
 177     n++;
 178
 179   res = gen_rtx_PARALLEL (GET_MODE (val), rtvec_alloc (n));
 180
 181   n = 0;
 182
 183   if (GET_CODE (val) == PARALLEL)
 184     for (i = 0; i < XVECLEN (val, 0); i++)
 185       XVECEXP (res, 0, n++) = XVECEXP (val, 0, i);
 186   else
 187     XVECEXP (res, 0, n++) = val;
 188
 189   if (GET_CODE (bnd) == PARALLEL)
 190     for (i = 0; i < XVECLEN (bnd, 0); i++)
 191       XVECEXP (res, 0, n++) = XVECEXP (bnd, 0, i);
 192   else
 193     XVECEXP (res, 0, n++) = bnd;
 194
 195   return res;
 196 }
 197
 198 /* If PAR is PARALLEL holding registers then transform
 199    it into PARALLEL holding EXPR_LISTs of those regs
 200    and zero constant (similar to how function value
 201    on multiple registers looks like).  */
 202 void
 203 chkp_put_regs_to_expr_list (rtx par)
 204 {
 205   int n;
 206
 207   if (GET_CODE (par) != PARALLEL
 208       || GET_CODE (XVECEXP (par, 0, 0)) == EXPR_LIST)
 209     return;
 210
 211   for (n = 0; n < XVECLEN (par, 0); n++)
 212     XVECEXP (par, 0, n) = gen_rtx_EXPR_LIST (VOIDmode,
 213                                              XVECEXP (par, 0, n),
 214                                              const0_rtx);
 215 }
 216
 217 /*  Search rtx PAR describing function return value for an
 218     item related to value at offset OFFS and return it.
 219     Return NULL if item was not found.  */
 220 rtx
 221 chkp_get_value_with_offs (rtx par, rtx offs)
 222 {
 223   int n;
 224
 225   gcc_assert (GET_CODE (par) == PARALLEL);
 226
 227   for (n = 0; n < XVECLEN (par, 0); n++)
 228     {
 229       rtx par_offs = XEXP (XVECEXP (par, 0, n), 1);
 230       if (INTVAL (offs) == INTVAL (par_offs))
 231         return XEXP (XVECEXP (par, 0, n), 0);
 232     }
 233
 234   return NULL;
 235 }
 236
 237 /* Emit instructions to store BOUNDS for pointer VALUE
 238    stored in MEM.
 239    Function is used by expand to pass bounds for args
 240    passed on stack.  */
 241 void
 242 chkp_emit_bounds_store (rtx bounds, rtx value, rtx mem)
 243 {
 244   gcc_assert (MEM_P (mem));
 245
 246   if (REG_P (bounds) || CONST_INT_P (bounds))
 247     {
 248       rtx ptr;
 249
 250       if (REG_P (value))
 251         ptr = value;
 252       else
 253         {
 254           rtx slot = adjust_address (value, Pmode, 0);
 255           ptr = gen_reg_rtx (Pmode);
 256           emit_move_insn (ptr, slot);
 257         }
 258
 259       if (CONST_INT_P (bounds))
 260         bounds = targetm.calls.load_bounds_for_arg (value, ptr, bounds);
 261
 262       targetm.calls.store_bounds_for_arg (ptr, mem,
 263                                           bounds, NULL);
 264     }
 265   else
 266     {
 267       int i;
 268
 269       gcc_assert (GET_CODE (bounds) == PARALLEL);
 270       gcc_assert (GET_CODE (value) == PARALLEL || MEM_P (value) || REG_P (value));
 271
 272       for (i = 0; i < XVECLEN (bounds, 0); i++)
 273         {
 274           rtx reg = XEXP (XVECEXP (bounds, 0, i), 0);
 275           rtx offs = XEXP (XVECEXP (bounds, 0, i), 1);
 276           rtx slot = adjust_address (mem, Pmode, INTVAL (offs));
 277           rtx ptr;
 278
 279           if (GET_CODE (value) == PARALLEL)
 280             ptr = chkp_get_value_with_offs (value, offs);
 281           else if (MEM_P (value))
 282             {
 283               rtx tmp = adjust_address (value, Pmode, INTVAL (offs));
 284               ptr = gen_reg_rtx (Pmode);
 285               emit_move_insn (ptr, tmp);
 286             }
 287           else
 288             ptr = gen_rtx_SUBREG (Pmode, value, INTVAL (offs));
 289
 290           targetm.calls.store_bounds_for_arg (ptr, slot, reg, NULL);
 291         }
 292     }
 293 }
 294
 295 /* Emit code to copy bounds for structure VALUE of type TYPE
 296    copied to SLOT.  */
 297 void
 298 chkp_copy_bounds_for_stack_parm (rtx slot, rtx value, tree type)
 299 {
 300   bitmap have_bound;
 301   bitmap_iterator bi;
 302   unsigned i;
 303   rtx tmp = NULL, bnd;
 304
 305   gcc_assert (TYPE_SIZE (type));
 306   gcc_assert (MEM_P (value));
 307   gcc_assert (MEM_P (slot));
 308   gcc_assert (RECORD_OR_UNION_TYPE_P (type));
 309
 310   bitmap_obstack_initialize (NULL);
 311   have_bound = BITMAP_ALLOC (NULL);
 312   chkp_find_bound_slots (type, have_bound);
 313
 314   EXECUTE_IF_SET_IN_BITMAP (have_bound, 0, i, bi)
 315     {
 316       rtx ptr = adjust_address (value, Pmode, i * POINTER_SIZE / 8);
 317       rtx to = adjust_address (slot, Pmode, i * POINTER_SIZE / 8);
 318
 319       if (!tmp)
 320         tmp = gen_reg_rtx (Pmode);
 321
 322       emit_move_insn (tmp, ptr);
 323       bnd = targetm.calls.load_bounds_for_arg (ptr, tmp, NULL);
 324       targetm.calls.store_bounds_for_arg (tmp, to, bnd, NULL);
 325     }
 326
 327   BITMAP_FREE (have_bound);
 328   bitmap_obstack_release (NULL);
 329 }