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 "machmode.h"
  29 #include "tm.h"
  30 #include "hard-reg-set.h"
  31 #include "input.h"
  32 #include "function.h"
  33 #include "rtl.h"
  34 #include "flags.h"
  35 #include "statistics.h"
  36 #include "double-int.h"
  37 #include "real.h"
  38 #include "fixed-value.h"
  39 #include "alias.h"
  40 #include "wide-int.h"
  41 #include "inchash.h"
  42 #include "tree.h"
  43 #include "insn-config.h"
  44 #include "expmed.h"
  45 #include "dojump.h"
  46 #include "explow.h"
  47 #include "calls.h"
  48 #include "emit-rtl.h"
  49 #include "varasm.h"
  50 #include "stmt.h"
  51 #include "expr.h"
  52 #include "target.h"
  53 #include "tree-ssa-alias.h"
  54 #include "internal-fn.h"
  55 #include "is-a.h"
  56 #include "predict.h"
  57 #include "basic-block.h"
  58 #include "fold-const.h"
  59 #include "gimple-expr.h"
  60 #include "gimple.h"
  61 #include "bitmap.h"
  62 #include "rtl-chkp.h"
  63 #include "tree-chkp.h"
  64 #include "hash-map.h"
  65
  66 static hash_map<tree, rtx> *chkp_rtx_bounds_map;
  67
  68 /* Get bounds rtx associated with NODE via
  69    chkp_set_rtl_bounds call.  */
  70 rtx
  71 chkp_get_rtl_bounds (tree node)
  72 {
  73   rtx *slot;
  74
  75   if (!chkp_rtx_bounds_map)
  76     return NULL_RTX;
  77
  78   slot = chkp_rtx_bounds_map->get (node);
  79   return slot ? *slot : NULL_RTX;
  80 }
  81
  82 /* Associate bounds rtx VAL with NODE.  */
  83 void
  84 chkp_set_rtl_bounds (tree node, rtx val)
  85 {
  86   if (!chkp_rtx_bounds_map)
  87     chkp_rtx_bounds_map = new hash_map<tree, rtx>;
  88
  89   chkp_rtx_bounds_map->put (node, val);
  90 }
  91
  92 /* Reset all bounds stored via chkp_set_rtl_bounds.  */
  93 void
  94 chkp_reset_rtl_bounds ()
  95 {
  96   if (!chkp_rtx_bounds_map)
  97     return;
  98
  99   delete chkp_rtx_bounds_map;
 100   chkp_rtx_bounds_map = NULL;
 101 }
 102
 103 /* Split SLOT identifying slot for function value or
 104    argument into two parts SLOT_VAL and SLOT_BND.
 105    First is the slot for regular value and the other one is
 106    for bounds.  */
 107 void
 108 chkp_split_slot (rtx slot, rtx *slot_val, rtx *slot_bnd)
 109 {
 110   int i;
 111   int val_num = 0;
 112   int bnd_num = 0;
 113   rtx *val_tmps;
 114   rtx *bnd_tmps;
 115
 116   *slot_bnd = 0;
 117
 118   if (!slot
 119       || GET_CODE (slot) != PARALLEL)
 120     {
 121       *slot_val = slot;
 122       return;
 123     }
 124
 125   val_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
 126   bnd_tmps = XALLOCAVEC (rtx, XVECLEN (slot, 0));
 127
 128   for (i = 0; i < XVECLEN (slot, 0); i++)
 129     {
 130       rtx elem = XVECEXP (slot, 0, i);
 131       rtx reg = GET_CODE (elem) == EXPR_LIST ? XEXP (elem, 0) : elem;
 132
 133       if (!reg)
 134         continue;
 135
 136       if (POINTER_BOUNDS_MODE_P (GET_MODE (reg)) || CONST_INT_P (reg))
 137         bnd_tmps[bnd_num++] = elem;
 138       else
 139         val_tmps[val_num++] = elem;
 140     }
 141
 142   gcc_assert (val_num);
 143
 144   if (!bnd_num)
 145     {
 146       *slot_val = slot;
 147       return;
 148     }
 149
 150   if ((GET_CODE (val_tmps[0]) == EXPR_LIST) || (val_num > 1))
 151     *slot_val = gen_rtx_PARALLEL (GET_MODE (slot),
 152                                   gen_rtvec_v (val_num, val_tmps));
 153   else
 154     *slot_val = val_tmps[0];
 155
 156   if ((GET_CODE (bnd_tmps[0]) == EXPR_LIST) || (bnd_num > 1))
 157     *slot_bnd = gen_rtx_PARALLEL (VOIDmode,
 158                                   gen_rtvec_v (bnd_num, bnd_tmps));
 159   else
 160     *slot_bnd = bnd_tmps[0];
 161 }
 162
 163 /* Join previously splitted to VAL and BND rtx for function
 164    value or argument and return it.  */
 165 rtx
 166 chkp_join_splitted_slot (rtx val, rtx bnd)
 167 {
 168   rtx res;
 169   int i, n = 0;
 170
 171   if (!bnd)
 172     return val;
 173
 174   if (GET_CODE (val) == PARALLEL)
 175     n += XVECLEN (val, 0);
 176   else
 177     n++;
 178
 179   if (GET_CODE (bnd) == PARALLEL)
 180     n += XVECLEN (bnd, 0);
 181   else
 182     n++;
 183
 184   res = gen_rtx_PARALLEL (GET_MODE (val), rtvec_alloc (n));
 185
 186   n = 0;
 187
 188   if (GET_CODE (val) == PARALLEL)
 189     for (i = 0; i < XVECLEN (val, 0); i++)
 190       XVECEXP (res, 0, n++) = XVECEXP (val, 0, i);
 191   else
 192     XVECEXP (res, 0, n++) = val;
 193
 194   if (GET_CODE (bnd) == PARALLEL)
 195     for (i = 0; i < XVECLEN (bnd, 0); i++)
 196       XVECEXP (res, 0, n++) = XVECEXP (bnd, 0, i);
 197   else
 198     XVECEXP (res, 0, n++) = bnd;
 199
 200   return res;
 201 }
 202
 203 /* If PAR is PARALLEL holding registers then transform
 204    it into PARALLEL holding EXPR_LISTs of those regs
 205    and zero constant (similar to how function value
 206    on multiple registers looks like).  */
 207 void
 208 chkp_put_regs_to_expr_list (rtx par)
 209 {
 210   int n;
 211
 212   if (GET_CODE (par) != PARALLEL
 213       || GET_CODE (XVECEXP (par, 0, 0)) == EXPR_LIST)
 214     return;
 215
 216   for (n = 0; n < XVECLEN (par, 0); n++)
 217     XVECEXP (par, 0, n) = gen_rtx_EXPR_LIST (VOIDmode,
 218                                              XVECEXP (par, 0, n),
 219                                              const0_rtx);
 220 }
 221
 222 /*  Search rtx PAR describing function return value for an
 223     item related to value at offset OFFS and return it.
 224     Return NULL if item was not found.  */
 225 rtx
 226 chkp_get_value_with_offs (rtx par, rtx offs)
 227 {
 228   int n;
 229
 230   gcc_assert (GET_CODE (par) == PARALLEL);
 231
 232   for (n = 0; n < XVECLEN (par, 0); n++)
 233     {
 234       rtx par_offs = XEXP (XVECEXP (par, 0, n), 1);
 235       if (INTVAL (offs) == INTVAL (par_offs))
 236         return XEXP (XVECEXP (par, 0, n), 0);
 237     }
 238
 239   return NULL;
 240 }
 241
 242 /* Emit instructions to store BOUNDS for pointer VALUE
 243    stored in MEM.
 244    Function is used by expand to pass bounds for args
 245    passed on stack.  */
 246 void
 247 chkp_emit_bounds_store (rtx bounds, rtx value, rtx mem)
 248 {
 249   gcc_assert (MEM_P (mem));
 250
 251   if (REG_P (bounds) || CONST_INT_P (bounds))
 252     {
 253       rtx ptr;
 254
 255       if (REG_P (value))
 256         ptr = value;
 257       else
 258         {
 259           rtx slot = adjust_address (value, Pmode, 0);
 260           ptr = gen_reg_rtx (Pmode);
 261           emit_move_insn (ptr, slot);
 262         }
 263
 264       if (CONST_INT_P (bounds))
 265         bounds = targetm.calls.load_bounds_for_arg (value, ptr, bounds);
 266
 267       targetm.calls.store_bounds_for_arg (ptr, mem,
 268                                           bounds, NULL);
 269     }
 270   else
 271     {
 272       int i;
 273
 274       gcc_assert (GET_CODE (bounds) == PARALLEL);
 275       gcc_assert (GET_CODE (value) == PARALLEL || MEM_P (value) || REG_P (value));
 276
 277       for (i = 0; i < XVECLEN (bounds, 0); i++)
 278         {
 279           rtx reg = XEXP (XVECEXP (bounds, 0, i), 0);
 280           rtx offs = XEXP (XVECEXP (bounds, 0, i), 1);
 281           rtx slot = adjust_address (mem, Pmode, INTVAL (offs));
 282           rtx ptr;
 283
 284           if (GET_CODE (value) == PARALLEL)
 285             ptr = chkp_get_value_with_offs (value, offs);
 286           else if (MEM_P (value))
 287             {
 288               rtx tmp = adjust_address (value, Pmode, INTVAL (offs));
 289               ptr = gen_reg_rtx (Pmode);
 290               emit_move_insn (ptr, tmp);
 291             }
 292           else
 293             ptr = gen_rtx_SUBREG (Pmode, value, INTVAL (offs));
 294
 295           targetm.calls.store_bounds_for_arg (ptr, slot, reg, NULL);
 296         }
 297     }
 298 }
 299
 300 /* Emit code to copy bounds for structure VALUE of type TYPE
 301    copied to SLOT.  */
 302 void
 303 chkp_copy_bounds_for_stack_parm (rtx slot, rtx value, tree type)
 304 {
 305   bitmap have_bound;
 306   bitmap_iterator bi;
 307   unsigned i;
 308   rtx tmp = NULL, bnd;
 309
 310   gcc_assert (TYPE_SIZE (type));
 311   gcc_assert (MEM_P (value));
 312   gcc_assert (MEM_P (slot));
 313   gcc_assert (RECORD_OR_UNION_TYPE_P (type));
 314
 315   bitmap_obstack_initialize (NULL);
 316   have_bound = BITMAP_ALLOC (NULL);
 317   chkp_find_bound_slots (type, have_bound);
 318
 319   EXECUTE_IF_SET_IN_BITMAP (have_bound, 0, i, bi)
 320     {
 321       rtx ptr = adjust_address (value, Pmode, i * POINTER_SIZE / 8);
 322       rtx to = adjust_address (slot, Pmode, i * POINTER_SIZE / 8);
 323
 324       if (!tmp)
 325         tmp = gen_reg_rtx (Pmode);
 326
 327       emit_move_insn (tmp, ptr);
 328       bnd = targetm.calls.load_bounds_for_arg (ptr, tmp, NULL);
 329       targetm.calls.store_bounds_for_arg (tmp, to, bnd, NULL);
 330     }
 331
 332   BITMAP_FREE (have_bound);
 333   bitmap_obstack_release (NULL);
 334 }