check_passes_sizeof.c

   1 /*
   2  * Copyright (C) 2012 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_extra.h"
  20 #include "smatch_slist.h"
  21
  22 #define NOBUF -2
  23
  24 static int my_id;
  25
  26 static struct expression *get_returned_expr(struct expression *expr)
  27 {
  28         struct statement *stmt;
  29
  30         stmt = last_ptr_list((struct ptr_list *)big_statement_stack);
  31         if (!stmt || stmt->type != STMT_EXPRESSION)
  32                 return NULL;
  33         if (stmt->expression->type != EXPR_ASSIGNMENT)
  34                 return NULL;
  35         if (stmt->expression->right != expr)
  36                 return NULL;
  37         return stmt->expression->left;
  38 }
  39
  40 static struct expression *remove_dereference(struct expression *expr)
  41 {
  42         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
  43                 return expr;
  44         expr = expr->unop;
  45         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
  46                 return expr;
  47         return expr->unop;
  48 }
  49
  50 static int get_buf_number(struct expression *call, struct expression *size_arg)
  51 {
  52         struct expression *arg;
  53         int idx = -1;
  54
  55         size_arg = strip_expr(size_arg->cast_expression);
  56         size_arg = remove_dereference(size_arg);
  57
  58         arg = get_returned_expr(call);
  59         if (arg && expr_equiv(arg, size_arg))
  60                 return idx;
  61
  62         FOR_EACH_PTR(call->args, arg) {
  63                 idx++;
  64                 if (expr_equiv(arg, size_arg))
  65                         return idx;
  66         } END_FOR_EACH_PTR(arg);
  67
  68         return NOBUF;
  69 }
  70
  71 static void match_call(struct expression *call)
  72 {
  73         struct expression *arg;
  74         char *name;
  75         int buf_nr;
  76         int i = -1;
  77
  78         if (call->fn->type != EXPR_SYMBOL)
  79                 return;
  80
  81         name = expr_to_var(call->fn);
  82         FOR_EACH_PTR(call->args, arg) {
  83                 i++;
  84                 if (arg->type != EXPR_SIZEOF)
  85                         continue;
  86                 buf_nr = get_buf_number(call, arg);
  87                 if (buf_nr == NOBUF)
  88                         sm_msg("info: sizeof_param '%s' %d", name, i);
  89                 else
  90                         sm_msg("info: sizeof_param '%s' %d %d", name, i, buf_nr);
  91         } END_FOR_EACH_PTR(arg);
  92         free_string(name);
  93 }
  94
  95 void check_passes_sizeof(int id)
  96 {
  97         if (!option_info)
  98                 return;
  99
 100         my_id = id;
 101         add_hook(&match_call, FUNCTION_CALL_HOOK);
 102 }