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 "scope.h"
  19 #include "smatch.h"
  20 #include "smatch_slist.h"
  21 #include "smatch_extra.h"
  22
  23 static int my_id;
  24
  25 static struct smatch_state *unmatched_state(struct sm_state *sm)
  26 {
  27         return alloc_bstate(-1ULL, -1ULL);
  28 }
  29
  30 static void match_assign(struct expression *expr)
  31 {
  32         sval_t sval;
  33
  34         if (expr->type != EXPR_ASSIGNMENT)
  35                 return;
  36
  37         if (expr->op != SPECIAL_AND_ASSIGN)
  38                 return;
  39
  40         if (!get_implied_value(expr->right, &sval))
  41                 return;
  42
  43         set_state_expr(my_id, expr->left, alloc_bstate(0, sval.uvalue));
  44 }
  45
  46 static void return_info_callback(int return_id, char *return_ranges,
  47                                  struct expression *returned_expr,
  48                                  int param,
  49                                  const char *printed_name,
  50                                  struct sm_state *sm)
  51 {
  52         unsigned long long bits_clear;
  53         char buffer[64];
  54         struct smatch_state *estate;
  55         struct bit_info *binfo;
  56         sval_t sval;
  57
  58         estate = get_state(SMATCH_EXTRA, sm->name, sm->sym);
  59         if (estate_get_single_value(estate, &sval))
  60                 return;
  61
  62         binfo = sm->state->data;
  63         bits_clear = binfo->possible;
  64
  65         if (bits_clear == 0)
  66                 return;
  67
  68         sprintf(buffer, "0x%llx", bits_clear);
  69         sql_insert_return_states(return_id, return_ranges, BIT_CLEAR, param, printed_name, buffer);
  70 }
  71
  72 struct smatch_state *merge_bstates_clear(struct smatch_state *one_state,
  73                                          struct smatch_state *two_state)
  74 {
  75         struct bit_info *one, *two;
  76
  77         one = one_state->data;
  78         two = two_state->data;
  79
  80         if (binfo_equiv(one, two))
  81                 return one_state;
  82
  83         return alloc_bstate(0, one->possible | two->possible);
  84 }
  85
  86 void register_param_bits_clear(int id)
  87 {
  88         my_id = id;
  89
  90         set_dynamic_states(my_id);
  91         add_hook(&match_assign, ASSIGNMENT_HOOK);
  92         add_unmatched_state_hook(my_id, &unmatched_state);
  93         add_merge_hook(my_id, &merge_bstates);
  94
  95         add_return_info_callback(my_id, return_info_callback);
  96 }