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
21static int my_id;
22
23static void match_shift_mask(struct expression *expr)
24{
25	struct expression *right, *shifter;
26	struct range_list *rl;
27	char *str;
28
29	expr = strip_expr(expr);
30	if (expr->type != EXPR_BINOP || expr->op != '&')
31		return;
32
33	if (get_type(expr->left) != &ullong_ctype)
34		return;
35
36	if (type_bits(get_type(expr->right)) == 64)
37		return;
38
39	right = strip_expr(expr->right);
40	if (right->type != EXPR_BINOP || right->op != SPECIAL_LEFTSHIFT)
41		return;
42
43	shifter = strip_expr(right->right);
44	get_real_absolute_rl(shifter, &rl);
45	if (rl_max(rl).uvalue < 32)
46		return;
47
48	str = expr_to_str(expr->right);
49	sm_warning("should '%s' be a 64 bit type?", str);
50	free_string(str);
51}
52
53static void match_shift_assignment(struct expression *expr)
54{
55	struct symbol *left_type, *right_type;
56	struct expression *right;
57	sval_t sval;
58	sval_t bits, shifter;
59	char *name;
60
61	right = strip_expr(expr->right);
62	if (right->type != EXPR_BINOP || right->op != SPECIAL_LEFTSHIFT)
63		return;
64
65	left_type = get_type(expr->left);
66	if (left_type != &llong_ctype && left_type != &ullong_ctype)
67		return;
68
69	right_type = get_type(expr->right);
70
71	if (type_bits(right_type) == 64)
72		return;
73
74	if (get_value(right, &sval))
75		return;
76
77	get_absolute_max(right->left, &bits);
78	get_absolute_max(right->right, &shifter);
79
80	bits = sval_cast(&ullong_ctype, bits);
81	if (sval_cmp_val(shifter, 32) < 0) {
82		sval = sval_binop(bits, SPECIAL_LEFTSHIFT, shifter);
83		if (sval_cmp_val(sval, UINT_MAX) < 0)
84			return;
85	}
86
87	name = expr_to_str_sym(right, NULL);
88	sm_warning("should '%s' be a 64 bit type?", name);
89	free_string(name);
90}
91
92void check_64bit_shift(int id)
93{
94	my_id = id;
95
96	add_hook(&match_shift_assignment, ASSIGNMENT_HOOK);
97	add_hook(&match_shift_mask, BINOP_HOOK);
98}
99