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