check_assigned_expr.c

   1 /*
   2  * Copyright (C) 2009 Dan Carpenter.
   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 /*
  19  * This is not a check.  It just saves an struct expression pointer
  20  * whenever something is assigned.  This can be used later on by other scripts.
  21  */
  22
  23 #include "smatch.h"
  24 #include "smatch_slist.h"
  25 #include "smatch_extra.h"
  26
  27 int check_assigned_expr_id;
  28 static int my_id;
  29 static int link_id;
  30
  31 static void undef(struct sm_state *sm, struct expression *mod_expr)
  32 {
  33         set_state(my_id, sm->name, sm->sym, &undefined);
  34 }
  35
  36 struct expression *get_assigned_expr(struct expression *expr)
  37 {
  38         struct smatch_state *state;
  39
  40         state = get_state_expr(my_id, expr);
  41         if (!state)
  42                 return NULL;
  43         return (struct expression *)state->data;
  44 }
  45
  46 struct expression *get_assigned_expr_name_sym(const char *name, struct symbol *sym)
  47 {
  48         struct smatch_state *state;
  49
  50         state = get_state(my_id, name, sym);
  51         if (!state)
  52                 return NULL;
  53         return (struct expression *)state->data;
  54 }
  55
  56 static struct smatch_state *alloc_my_state(struct expression *expr)
  57 {
  58         struct smatch_state *state;
  59         char *name;
  60
  61         state = __alloc_smatch_state(0);
  62         expr = strip_expr(expr);
  63         name = expr_to_str(expr);
  64         state->name = alloc_sname(name);
  65         free_string(name);
  66         state->data = expr;
  67         return state;
  68 }
  69
  70 static void match_assignment(struct expression *expr)
  71 {
  72         struct symbol *left_sym, *right_sym;
  73         char *left_name = NULL;
  74         char *right_name = NULL;
  75
  76         if (expr->op != '=')
  77                 return;
  78         if (is_fake_call(expr->right) || __in_fake_assign)
  79                 return;
  80
  81         left_name = expr_to_var_sym(expr->left, &left_sym);
  82         if (!left_name || !left_sym)
  83                 goto free;
  84         set_state(my_id, left_name, left_sym, alloc_my_state(expr->right));
  85
  86         right_name = expr_to_var_sym(expr->right, &right_sym);
  87         if (!right_name || !right_sym)
  88                 goto free;
  89
  90         store_link(link_id, right_name, right_sym, left_name, left_sym);
  91
  92 free:
  93         free_string(left_name);
  94         free_string(right_name);
  95 }
  96
  97 void check_assigned_expr(int id)
  98 {
  99         my_id = check_assigned_expr_id = id;
 100         add_hook(&match_assignment, ASSIGNMENT_HOOK_AFTER);
 101         add_modification_hook(my_id, &undef);
 102 }
 103
 104 void check_assigned_expr_links(int id)
 105 {
 106         link_id = id;
 107         set_up_link_functions(my_id, link_id);
 108 }
 109