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