11506 smatch resync
1 /* 2 * Copyright (C) 2014 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 20 static int my_id; 21 22 static void match_binop(struct expression *expr) 23 { 24 struct symbol *type; 25 sval_t bits; 26 27 if (expr->op != SPECIAL_RIGHTSHIFT) 28 return; 29 30 if (!get_implied_value(expr->right, &bits)) 31 return; 32 33 type = get_type(expr->left); 34 if (!type) 35 return; 36 if (type_bits(type) == -1 || type_bits(type) > bits.value) 37 return; 38 if (is_ignored_expr(my_id, expr)) 39 return; 40 sm_warning("right shifting more than type allows %d vs %lld", type_bits(type), bits.value); 41 } 42 43 static void match_binop2(struct expression *expr) 44 { 45 struct expression *left; 46 struct expression *tmp; 47 sval_t mask, shift; 48 49 if (expr->op != SPECIAL_RIGHTSHIFT) 50 return; 51 52 left = strip_expr(expr->left); 53 tmp = get_assigned_expr(left); 54 if (tmp) 55 left = tmp; 56 if (left->type != EXPR_BINOP || left->op != '&') 57 return; 58 59 if (!get_implied_value(expr->right, &shift)) 60 return; 61 if (!get_implied_value(left->right, &mask)) 62 return; 63 64 if (mask.uvalue >> shift.uvalue) 65 return; 66 67 sm_warning("mask and shift to zero"); 68 } 69 70 static void match_assign(struct expression *expr) 71 { 72 struct symbol *type; 73 sval_t bits; 74 75 if (expr->op != SPECIAL_SHR_ASSIGN) 76 return; 77 78 if (!get_implied_value(expr->right, &bits)) 79 return; 80 type = get_type(expr->left); 81 if (!type) 82 return; 83 if (type_bits(type) > bits.value) 84 return; 85 sm_warning("right shift assign to zero"); 86 } 87 88 void check_shift_to_zero(int id) 89 { 90 my_id = id; 91 92 add_hook(&match_binop, BINOP_HOOK); 93 add_hook(&match_binop2, BINOP_HOOK); 94 95 add_hook(&match_assign, ASSIGNMENT_HOOK); 96 97 } --- EOF ---