/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2011 Daniel Marjamäki and Cppcheck team. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ //--------------------------------------------------------------------------- // Check for assignment / condition mismatches //--------------------------------------------------------------------------- #include "checkassignif.h" #include "symboldatabase.h" //--------------------------------------------------------------------------- // Register this check class (by creating a static instance of it) namespace { CheckAssignIf instance; } void CheckAssignIf::assignIf() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->str() != "=") continue; if (Token::Match(tok->tokAt(-2), "[;{}] %var% = %var% [&|] %num% ;")) { const unsigned int varid(tok->previous()->varId()); if (varid == 0) continue; const char bitop(tok->strAt(2).at(0)); const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(3)); if (num < 0) continue; for (const Token *tok2 = tok->tokAt(4); tok2; tok2 = tok2->next()) { if (tok2->str() == "(" || tok2->str() == "}" || tok2->str() == "=") break; if (Token::Match(tok2,"if ( %varid% %any% %num% &&|%oror%|)", varid)) { const std::string op(tok2->strAt(3)); const MathLib::bigint num2 = MathLib::toLongNumber(tok2->strAt(4)); if (op == "==" && (num & num2) != ((bitop=='&') ? num2 : num)) assignIfError(tok2, false); else if (op == "!=" && (num & num2) != ((bitop=='&') ? num2 : num)) assignIfError(tok2, true); break; } } } } } void CheckAssignIf::assignIfError(const Token *tok, bool result) { reportError(tok, Severity::style, "assignIfError", "Mismatching assignment and comparison, comparison is always " + std::string(result ? "true" : "false")); } void CheckAssignIf::comparison() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->str() != "&") continue; if (Token::Match(tok, "& %num% )| ==|!= %num% &&|%oror%|)")) { const MathLib::bigint num1 = MathLib::toLongNumber(tok->strAt(1)); if (num1 < 0) continue; const Token *compareToken = tok->tokAt(2); if (compareToken->str() == ")") { if (!Token::Match(compareToken->link()->previous(), "(|%oror%|&&")) continue; compareToken = compareToken->next(); } const MathLib::bigint num2 = MathLib::toLongNumber(compareToken->strAt(1)); if (num2 < 0) continue; if ((num1 & num2) != num2) { const std::string op(compareToken->str()); comparisonError(tok, num1, op, num2, op=="==" ? false : true); } } } } void CheckAssignIf::comparisonError(const Token *tok, MathLib::bigint value1, const std::string &op, MathLib::bigint value2, bool result) { std::ostringstream expression; expression << std::hex << "(X & 0x" << value1 << ") " << op << " 0x" << value2; const std::string errmsg("Expression '" + expression.str() + "' is always " + (result?"true":"false") + "\n" "The expression '" + expression.str() + "' is always " + (result?"true":"false") + ". Check carefully constants and operators used, these errors might be hard to " "spot sometimes. In case of complex expression it might help to split it to " "separate expressions."); reportError(tok, Severity::style, "comparisonError", errmsg); } void CheckAssignIf::multiCondition() { if (!_settings->isEnabled("style")) return; const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase(); for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) { if (i->type == Scope::eIf && Token::Match(i->classDef, "if ( %var% & %num% ) {")) { const Token* const tok = i->classDef; const unsigned int varid(tok->tokAt(2)->varId()); if (varid == 0) continue; const MathLib::bigint num1 = MathLib::toLongNumber(tok->strAt(4)); if (num1 < 0) continue; const Token *tok2 = tok->linkAt(6); while (Token::simpleMatch(tok2, "} else { if (")) { // Goto '(' const Token * const opar = tok2->tokAt(4); // tok2: skip if-block tok2 = opar->link(); if (Token::simpleMatch(tok2, ") {")) tok2 = tok2->next()->link(); // check condition.. if (Token::Match(opar, "( %varid% ==|& %num% &&|%oror%|)", varid)) { const MathLib::bigint num2 = MathLib::toLongNumber(opar->strAt(3)); if (num2 < 0) continue; if ((num1 & num2) == num2) { multiConditionError(opar, tok->linenr()); } } } } } } void CheckAssignIf::multiConditionError(const Token *tok, unsigned int line1) { std::ostringstream errmsg; errmsg << "'else if' condition matches previous condition at line " << line1; reportError(tok, Severity::style, "multiCondition", errmsg.str()); }