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