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