check_missing_error_code2.c

   1 /*
   2  * Copyright (C) 2022 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 #include "smatch.h"
  20 #include "smatch_extra.h"
  21 #include "smatch_slist.h"
  22
  23 static int my_id;
  24
  25 static struct statement *get_if_statement(struct expression *expr)
  26 {
  27         struct statement *stmt;
  28
  29         stmt = get_parent_stmt(expr);
  30         if (!stmt || stmt->type != STMT_RETURN)
  31                 return NULL;
  32         stmt = stmt_get_parent_stmt(stmt);
  33         if (stmt && stmt->type == STMT_COMPOUND)
  34                 stmt = stmt_get_parent_stmt(stmt);
  35         if (!stmt)
  36                 return NULL;
  37
  38         if (stmt->type != STMT_IF)
  39                 return NULL;
  40
  41         return stmt;
  42 }
  43
  44 static bool condition_matches(struct expression *cond, struct expression *expr)
  45 {
  46         expr = strip_expr(expr);
  47         cond = strip_expr(cond);
  48
  49         while (cond) {
  50                 if (cond->type == EXPR_PREOP &&
  51                     (cond->op == '(' || cond->op == '!')) {
  52                         cond = strip_expr(cond->unop);
  53                         continue;
  54                 }
  55                 if (cond->type == EXPR_COMPARE &&
  56                     (cond->op == SPECIAL_EQUAL || cond->op == SPECIAL_NOTEQUAL) &&
  57                      expr_is_zero(cond->right)) {
  58                         cond = strip_expr(cond->left);
  59                         continue;
  60                 }
  61                 break;
  62         }
  63
  64         if (expr_equiv(cond, expr))
  65                 return true;
  66
  67         return false;
  68 }
  69
  70 static struct expression *get_orig_call(struct expression *expr)
  71 {
  72         struct expression *orig;
  73
  74         orig = get_assigned_expr(expr);
  75         if (!orig || orig->type != EXPR_CALL)
  76                 return NULL;
  77
  78         return orig;
  79 }
  80
  81 static void match_return(struct expression *expr)
  82 {
  83         struct expression *call;
  84         struct statement *stmt;
  85         sval_t sval;
  86         char *name;
  87
  88         if (!expr || expr->type != EXPR_SYMBOL)
  89                 return;
  90
  91         if (get_type(expr) != &int_ctype)
  92                 return;
  93
  94         if (!get_implied_value(expr, &sval) || sval.value != 0)
  95                 return;
  96
  97         stmt = get_if_statement(expr);
  98         if (!stmt)
  99                 return;
 100         if (condition_matches(stmt->if_conditional, expr))
 101                 return;
 102
 103         call = get_orig_call(expr);
 104         if (!call)
 105                 return;
 106
 107         if (call->pos.line >= stmt->pos.line)
 108                 return;
 109
 110         if (call->pos.line + 5 >= expr->pos.line)
 111                 return;
 112
 113         name = expr_to_str(expr);
 114         sm_warning("missing error code? '%s'", name);
 115         free_string(name);
 116 }
 117
 118 void check_missing_error_code2(int id)
 119 {
 120         my_id = id;
 121
 122         add_hook(&match_return, RETURN_HOOK);
 123 }