smatch_param_bits_clear.c

   1 /*
   2  * Copyright (C) 2021 Oracle
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 #include "smatch.h"
  19 #include "smatch_slist.h"
  20 #include "smatch_extra.h"
  21
  22 static int my_id;
  23
  24 static struct smatch_state *unmatched_state(struct sm_state *sm)
  25 {
  26         return alloc_bstate(-1ULL, -1ULL);
  27 }
  28
  29 static void match_assign(struct expression *expr)
  30 {
  31         sval_t sval;
  32
  33         if (expr->type != EXPR_ASSIGNMENT)
  34                 return;
  35
  36         if (expr->op != SPECIAL_AND_ASSIGN)
  37                 return;
  38
  39         if (!get_implied_value(expr->right, &sval))
  40                 return;
  41
  42         set_state_expr(my_id, expr->left, alloc_bstate(0, sval.uvalue));
  43 }
  44
  45 static void return_info_callback(int return_id, char *return_ranges,
  46                                  struct expression *returned_expr,
  47                                  int param,
  48                                  const char *printed_name,
  49                                  struct sm_state *sm)
  50 {
  51         unsigned long long bits_clear;
  52         char buffer[64];
  53         struct smatch_state *estate;
  54         struct bit_info *binfo;
  55         sval_t sval;
  56
  57         estate = get_state(SMATCH_EXTRA, sm->name, sm->sym);
  58         if (estate_get_single_value(estate, &sval))
  59                 return;
  60
  61         binfo = sm->state->data;
  62         bits_clear = binfo->possible;
  63
  64         if (bits_clear == 0)
  65                 return;
  66
  67         sprintf(buffer, "0x%llx", bits_clear);
  68         sql_insert_return_states(return_id, return_ranges, BIT_CLEAR, param, printed_name, buffer);
  69 }
  70
  71 struct smatch_state *merge_bstates_clear(struct smatch_state *one_state,
  72                                          struct smatch_state *two_state)
  73 {
  74         struct bit_info *one, *two;
  75
  76         one = one_state->data;
  77         two = two_state->data;
  78
  79         if (binfo_equiv(one, two))
  80                 return one_state;
  81
  82         return alloc_bstate(0, one->possible | two->possible);
  83 }
  84
  85 void register_param_bits_clear(int id)
  86 {
  87         my_id = id;
  88
  89         set_dynamic_states(my_id);
  90         add_hook(&match_assign, ASSIGNMENT_HOOK);
  91         add_unmatched_state_hook(my_id, &unmatched_state);
  92         add_merge_hook(my_id, &merge_bstates);
  93
  94         add_return_info_callback(my_id, return_info_callback);
  95 }