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 
alloc_my_state(struct expression * expr)28 static struct smatch_state *alloc_my_state(struct expression *expr)
29 {
30 	struct smatch_state *state;
31 	char *name;
32 
33 	expr = strip_expr(expr);
34 	name = expr_to_str(expr);
35 	if (!name)
36 		return NULL;
37 
38 	state = __alloc_smatch_state(0);
39 	state->name = alloc_sname(name);
40 	free_string(name);
41 	state->data = expr;
42 	return state;
43 }
44 
defined_inside_macro(struct position macro_pos,struct expression * expr)45 static int defined_inside_macro(struct position macro_pos, struct expression *expr)
46 {
47 	char *name;
48 	struct symbol *sym;
49 	int ret = 0;
50 
51 	name = expr_to_var_sym(expr, &sym);
52 	if (!name || !sym)
53 		goto free;
54 	if (!sym->scope || !sym->scope->token)
55 		goto free;
56 	if (positions_eq(macro_pos, sym->scope->token->pos))
57 		ret = 1;
58 free:
59 	free_string(name);
60 	return ret;
61 }
62 
affected_inside_macro_before(struct expression * expr)63 static int affected_inside_macro_before(struct expression *expr)
64 {
65 	struct sm_state *sm;
66 	struct sm_state *tmp;
67 	struct expression *old_mod;
68 
69 	sm = get_sm_state_expr(my_id, expr);
70 	if (!sm)
71 		return 0;
72 
73 	FOR_EACH_PTR(sm->possible, tmp) {
74 		old_mod = tmp->state->data;
75 		if (!old_mod)
76 			continue;
77 		if (positions_eq(old_mod->pos, expr->pos))
78 			return 1;
79 	} END_FOR_EACH_PTR(tmp);
80 	return 0;
81 }
82 
is_ignored_macro(const char * macro)83 static int is_ignored_macro(const char *macro)
84 {
85 	char *tmp;
86 
87 	FOR_EACH_PTR(ignored_macros, tmp) {
88 		if (!strcmp(tmp, macro))
89 			return 1;
90 	} END_FOR_EACH_PTR(tmp);
91 	return 0;
92 }
93 
match_unop(struct expression * raw_expr)94 static void match_unop(struct expression *raw_expr)
95 {
96 	struct expression *expr;
97 	char *macro, *name;
98 
99 	if (raw_expr->op != SPECIAL_INCREMENT && raw_expr->op != SPECIAL_DECREMENT)
100 		return;
101 
102 	macro = get_macro_name(raw_expr->pos);
103 	if (!macro)
104 		return;
105 
106 	expr = strip_expr(raw_expr->unop);
107 
108 	if (defined_inside_macro(expr->pos, expr))
109 		return;
110 
111 	if (is_ignored_macro(macro))
112 		return;
113 
114 	if (!affected_inside_macro_before(expr)) {
115 		set_state_expr(my_id, expr, alloc_my_state(expr));
116 		old_pos = expr->pos;
117 		return;
118 	}
119 
120 	if (!positions_eq(old_pos, expr->pos))
121 		return;
122 
123 	name = expr_to_str(raw_expr);
124 	sm_warning("side effect in macro '%s' doing '%s'",
125 		macro, name);
126 	free_string(name);
127 }
128 
match_stmt(struct statement * stmt)129 static void match_stmt(struct statement *stmt)
130 {
131 	if (!positions_eq(old_pos, stmt->pos))
132 		old_pos.line = 0;
133 }
134 
register_ignored_macros(void)135 static void register_ignored_macros(void)
136 {
137 	struct token *token;
138 	char *macro;
139 	char name[256];
140 
141 	snprintf(name, 256, "%s.ignore_side_effects", option_project_str);
142 
143 	token = get_tokens_file(name);
144 	if (!token)
145 		return;
146 	if (token_type(token) != TOKEN_STREAMBEGIN)
147 		return;
148 	token = token->next;
149 	while (token_type(token) != TOKEN_STREAMEND) {
150 		if (token_type(token) != TOKEN_IDENT)
151 			return;
152 		macro = alloc_string(show_ident(token->ident));
153 		add_ptr_list(&ignored_macros, macro);
154 		token = token->next;
155 	}
156 	clear_token_alloc();
157 }
158 
check_macro_side_effects(int id)159 void check_macro_side_effects(int id)
160 {
161 	my_id = id;
162 
163 	if (!option_spammy)
164 		return;
165 
166 	set_dynamic_states(my_id);
167 	add_hook(&match_unop, OP_HOOK);
168 	add_hook(&match_stmt, STMT_HOOK);
169 	register_ignored_macros();
170 }
171