check_macro_side_effects.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 "scope.h"
  19 #include "smatch.h"
  20 #include "smatch_slist.h"
  21 #include "smatch_expression_stacks.h"
  22
  23 static int my_id;
  24
  25 static struct string_list *ignored_macros;
  26 static struct position old_pos;
  27
  28 static struct smatch_state *alloc_my_state(struct expression *expr)
  29 {
  30         struct smatch_state *state;
  31         char *name;
  32
  33         state = __alloc_smatch_state(0);
  34         expr = strip_expr(expr);
  35         name = expr_to_str(expr);
  36         state->name = alloc_sname(name);
  37         free_string(name);
  38         state->data = expr;
  39         return state;
  40 }
  41
  42 static int defined_inside_macro(struct position macro_pos, struct expression *expr)
  43 {
  44         char *name;
  45         struct symbol *sym;
  46         int ret = 0;
  47
  48         name = expr_to_var_sym(expr, &sym);
  49         if (!name || !sym)
  50                 goto free;
  51         if (!sym->scope || !sym->scope->token)
  52                 goto free;
  53         if (positions_eq(macro_pos, sym->scope->token->pos))
  54                 ret = 1;
  55 free:
  56         free_string(name);
  57         return ret;
  58 }
  59
  60 static int affected_inside_macro_before(struct expression *expr)
  61 {
  62         struct sm_state *sm;
  63         struct sm_state *tmp;
  64         struct expression *old_mod;
  65
  66         sm = get_sm_state_expr(my_id, expr);
  67         if (!sm)
  68                 return 0;
  69
  70         FOR_EACH_PTR(sm->possible, tmp) {
  71                 old_mod = tmp->state->data;
  72                 if (!old_mod)
  73                         continue;
  74                 if (positions_eq(old_mod->pos, expr->pos))
  75                         return 1;
  76         } END_FOR_EACH_PTR(tmp);
  77         return 0;
  78 }
  79
  80 static int is_ignored_macro(const char *macro)
  81 {
  82         char *tmp;
  83
  84         FOR_EACH_PTR(ignored_macros, tmp) {
  85                 if (!strcmp(tmp, macro))
  86                         return 1;
  87         } END_FOR_EACH_PTR(tmp);
  88         return 0;
  89 }
  90
  91 static void match_unop(struct expression *raw_expr)
  92 {
  93         struct expression *expr;
  94         char *macro, *name;
  95
  96         if (raw_expr->op != SPECIAL_INCREMENT && raw_expr->op != SPECIAL_DECREMENT)
  97                 return;
  98
  99         macro = get_macro_name(raw_expr->pos);
 100         if (!macro)
 101                 return;
 102
 103         expr = strip_expr(raw_expr->unop);
 104
 105         if (defined_inside_macro(expr->pos, expr))
 106                 return;
 107
 108         if (is_ignored_macro(macro))
 109                 return;
 110
 111         if (!affected_inside_macro_before(expr)) {
 112                 set_state_expr(my_id, expr, alloc_my_state(expr));
 113                 old_pos = expr->pos;
 114                 return;
 115         }
 116
 117         if (!positions_eq(old_pos, expr->pos))
 118                 return;
 119
 120         name = expr_to_str(raw_expr);
 121         sm_msg("warn: side effect in macro '%s' doing '%s'",
 122                 macro, name);
 123         free_string(name);
 124 }
 125
 126 static void match_stmt(struct statement *stmt)
 127 {
 128         if (!positions_eq(old_pos, stmt->pos))
 129                 old_pos.line = 0;
 130 }
 131
 132 static void register_ignored_macros(void)
 133 {
 134         struct token *token;
 135         char *macro;
 136         char name[256];
 137
 138         snprintf(name, 256, "%s.ignore_side_effects", option_project_str);
 139
 140         token = get_tokens_file(name);
 141         if (!token)
 142                 return;
 143         if (token_type(token) != TOKEN_STREAMBEGIN)
 144                 return;
 145         token = token->next;
 146         while (token_type(token) != TOKEN_STREAMEND) {
 147                 if (token_type(token) != TOKEN_IDENT)
 148                         return;
 149                 macro = alloc_string(show_ident(token->ident));
 150                 add_ptr_list(&ignored_macros, macro);
 151                 token = token->next;
 152         }
 153         clear_token_alloc();
 154 }
 155
 156 void check_macro_side_effects(int id)
 157 {
 158         my_id = id;
 159
 160         if (!option_spammy)
 161                 return;
 162
 163         add_hook(&match_unop, OP_HOOK);
 164         add_hook(&match_stmt, STMT_HOOK);
 165         register_ignored_macros();
 166 }