| 165 | //--------------------------------------------------------------------------- |
| 166 | |
| 167 | void CheckTypeImpl::checkIntegerOverflow() |
| 168 | { |
| 169 | // unknown sizeof(int) => can't run this checker |
| 170 | if (mSettings.platform.type == Platform::Type::Unspecified || mSettings.platform.int_bit >= MathLib::bigint_bits) |
| 171 | return; |
| 172 | |
| 173 | logChecker("CheckType::checkIntegerOverflow"); // platform |
| 174 | |
| 175 | for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) { |
| 176 | if (!tok->isArithmeticalOp()) |
| 177 | continue; |
| 178 | |
| 179 | // is result signed integer? |
| 180 | const ValueType *vt = tok->valueType(); |
| 181 | if (!vt || !vt->isIntegral() || vt->sign != ValueType::Sign::SIGNED) |
| 182 | continue; |
| 183 | |
| 184 | unsigned int bits; |
| 185 | if (vt->type == ValueType::Type::INT) |
| 186 | bits = mSettings.platform.int_bit; |
| 187 | else if (vt->type == ValueType::Type::LONG) |
| 188 | bits = mSettings.platform.long_bit; |
| 189 | else if (vt->type == ValueType::Type::LONGLONG) |
| 190 | bits = mSettings.platform.long_long_bit; |
| 191 | else |
| 192 | continue; |
| 193 | |
| 194 | if (bits >= MathLib::bigint_bits) |
| 195 | continue; |
| 196 | |
| 197 | // max value according to platform settings. |
| 198 | const MathLib::bigint maxvalue = (static_cast<MathLib::biguint>(1) << (bits - 1)) - 1; |
| 199 | |
| 200 | // is there a overflow result value |
| 201 | bool isOverflow = true; |
| 202 | const ValueFlow::Value *value = tok->getValueGE(maxvalue + 1, mSettings); |
| 203 | if (!value) { |
| 204 | value = tok->getValueLE(-maxvalue - 2, mSettings); |
| 205 | isOverflow = false; |
| 206 | } |
| 207 | if (!value || !mSettings.isEnabled(value,false)) |
| 208 | continue; |
| 209 | |
| 210 | // For left shift, it's common practice to shift into the sign bit |
| 211 | if (tok->str() == "<<" && value->intvalue > 0 && value->intvalue < (static_cast<MathLib::biguint>(1) << bits)) |
| 212 | continue; |
| 213 | |
| 214 | integerOverflowError(tok, *value, isOverflow); |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | static std::string getMessageId(const ValueFlow::Value &value, const char id[]) |
| 219 | { |
no test coverage detected