/* * 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 . */ //--------------------------------------------------------------------------- #include "checkother.h" #include "mathlib.h" #include "symboldatabase.h" #include #include // fabs() #include #include // find_if() //--------------------------------------------------------------------------- // Register this check class (by creating a static instance of it) namespace { CheckOther instance; } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkIncrementBoolean() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "%var% ++")) { if (tok->varId()) { const Variable *var = symbolDatabase->getVariableFromVarId(tok->varId()); if (var && var->typeEndToken()->str() == "bool") incrementBooleanError(tok); } } } } void CheckOther::incrementBooleanError(const Token *tok) { reportError( tok, Severity::style, "incrementboolean", "The use of a variable of type bool with the ++ postfix operator is always true and deprecated by the C++ Standard.\n" "The operand of a postfix increment operator may be of type bool but it is deprecated by C++ Standard (Annex D-1) and the operand is always set to true\n" ); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::clarifyCalculation() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->strAt(1) == "?") { // condition const Token *cond = tok; if (cond->isName() || cond->isNumber()) cond = cond->previous(); else if (cond->str() == ")") cond = cond->link()->previous(); else continue; if (cond && cond->str() == "!") cond = cond->previous(); if (!cond) continue; // calculation if (!cond->isArithmeticalOp()) continue; const std::string &op = cond->str(); cond = cond->previous(); // skip previous multiplications.. while (cond && cond->strAt(-1) == "*" && (cond->isName() || cond->isNumber())) cond = cond->tokAt(-2); if (!cond) continue; // first multiplication operand if (cond->str() == ")") { clarifyCalculationError(cond, op); } else if (cond->isName() || cond->isNumber()) { if (Token::Match(cond->previous(),("return|=|+|-|,|(|"+op).c_str())) clarifyCalculationError(cond, op); } } } } void CheckOther::clarifyCalculationError(const Token *tok, const std::string &op) { // suspicious calculation const std::string calc("'a" + op + "b?c:d'"); // recommended calculation #1 const std::string s1("'(a" + op + "b)?c:d'"); // recommended calculation #2 const std::string s2("'a" + op + "(b?c:d)'"); reportError(tok, Severity::style, "clarifyCalculation", "Clarify calculation precedence for " + op + " and ?\n" "Suspicious calculation. Please use parentheses to clarify the code. " "The code " + calc + " should be written as either " + s1 + " or " + s2 + "."); } //--------------------------------------------------------------------------- // Clarify condition '(x = a < 0)' into '((x = a) < 0)' or '(x = (a < 0))' // Clarify condition '(a & b == c)' into '((a & b) == c)' or '(a & (b == c))' //--------------------------------------------------------------------------- void CheckOther::clarifyCondition() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "( %var% [=&|^]")) { for (const Token *tok2 = tok->tokAt(3); tok2; tok2 = tok2->next()) { if (tok2->str() == "(" || tok2->str() == "[") tok2 = tok2->link(); else if (Token::Match(tok2, "<|<=|==|!=|>|>=")) { // This might be a template if (!_tokenizer->code_is_c() && Token::Match(tok2->previous(), "%var% <")) break; clarifyConditionError(tok, tok->strAt(2) == "=", false); break; } else if (!tok2->isName() && !tok2->isNumber() && tok2->str() != ".") break; } } } // using boolean result in bitwise operation ! x [&|^] for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "!|<|<=|==|!=|>|>=")) { const Token *tok2 = tok->next(); // Todo: There are false positives if '(' if encountered. It // is assumed there is something like '(char *)&..' and therefore // it bails out. if (Token::Match(tok2, "(|&")) continue; while (tok2 && (tok2->isName() || tok2->isNumber() || Token::Match(tok2,".|(|["))) { if (Token::Match(tok2, "(|[")) tok2 = tok2->link(); tok2 = tok2->next(); } if (Token::Match(tok2, "[&|^]")) { // don't write false positives when templates are used if (Token::Match(tok, "<|>") && (Token::Match(tok2, "& ,|>") || Token::simpleMatch(tok2->previous(), "const &"))) continue; clarifyConditionError(tok,false,true); } } } } void CheckOther::clarifyConditionError(const Token *tok, bool assign, bool boolop) { std::string errmsg; if (assign) errmsg = "Suspicious condition (assignment+comparison), it can be clarified with parentheses"; else if (boolop) errmsg = "Boolean result is used in bitwise operation. Clarify expression with parentheses\n" "Suspicious expression. Boolean result is used in bitwise operation. The ! operator " "and the comparison operators have higher precedence than bitwise operators. " "It is recommended that the expression is clarified with parentheses."; else errmsg = "Suspicious condition (bitwise operator + comparison), it can be clarified with parentheses\n" "Suspicious condition. Comparison operators have higher precedence than bitwise operators. Please clarify the condition with parentheses."; reportError(tok, Severity::style, "clarifyCondition", errmsg); } //--------------------------------------------------------------------------- // if (bool & bool) -> if (bool && bool) // if (bool | bool) -> if (bool || bool) //--------------------------------------------------------------------------- void CheckOther::checkBitwiseOnBoolean() { if (!_settings->isEnabled("style")) return; // danmar: this is inconclusive because I don't like that there are // warnings for calculations. Example: set_flag(a & b); if (!_settings->inconclusive) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "(|.|return %var% [&|]")) { if (tok->next()->varId()) { const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->next()->varId()); if (var && (var->typeStartToken() == var->typeEndToken()) && var->typeStartToken()->str() == "bool") { bitwiseOnBooleanError(tok->next(), tok->next()->str(), tok->strAt(2) == "&" ? "&&" : "||"); } } } } } void CheckOther::bitwiseOnBooleanError(const Token *tok, const std::string &varname, const std::string &op) { reportInconclusiveError(tok, Severity::style, "bitwiseOnBoolean", "Boolean variable '" + varname + "' is used in bitwise operation. Did you mean " + op + " ?"); } void CheckOther::checkSuspiciousSemicolon() { if (!_settings->inconclusive || !_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Look for "if(); {}", "for(); {}" or "while(); {}" if (Token::Match(tok, "if|for|while (")) { const Token *end = tok->next()->link(); if (!end) continue; // Ensure the semicolon is at the same line number as the if/for/while statement // and the {..} block follows it without an extra empty line. if (Token::simpleMatch(end, ") { ; } {") && end->linenr() == end->tokAt(2)->linenr() && end->linenr()+1 >= end->tokAt(4)->linenr()) { SuspiciousSemicolonError(tok); } } } } void CheckOther::SuspiciousSemicolonError(const Token* tok) { reportInconclusiveError(tok, Severity::warning, "suspiciousSemicolon", "Suspicious use of ; at the end of 'if/for/while' statement."); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::warningOldStylePointerCast() { if (!_settings->isEnabled("style")) { return; } if (!_tokenizer->isCPP()) { return; } for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Old style pointer casting.. if (!Token::Match(tok, "( const| %type% * ) %var%") && !Token::Match(tok, "( const| %type% * ) (| new")) continue; unsigned char addToIndex = 0; if (tok->strAt(1) == "const") addToIndex = 1; if (tok->strAt(4 + addToIndex) == "const") continue; // Is "type" a class? const std::string pattern("class " + tok->strAt(1 + addToIndex)); if (!Token::findmatch(_tokenizer->tokens(), pattern.c_str())) continue; cstyleCastError(tok); } } void CheckOther::cstyleCastError(const Token *tok) { reportError(tok, Severity::style, "cstyleCast", "C-style pointer casting"); } //--------------------------------------------------------------------------- // fflush(stdin) <- fflush only applies to output streams in ANSI C //--------------------------------------------------------------------------- void CheckOther::checkFflushOnInputStream() { const Token *tok = _tokenizer->tokens(); while (tok && ((tok = Token::findsimplematch(tok, "fflush ( stdin )")) != NULL)) { fflushOnInputStreamError(tok, tok->strAt(2)); tok = tok->tokAt(4); } } void CheckOther::fflushOnInputStreamError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "fflushOnInputStream", "fflush() called on input stream \"" + varname + "\" may result in undefined behaviour"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkSizeofForNumericParameter() { // TODO: write sensible error message if char constant is used // see ticket #3179 if (!_settings->experimental) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "sizeof ( %num% )") || Token::Match(tok, "sizeof %num%") ) { sizeofForNumericParameterError(tok); } } } void CheckOther::sizeofForNumericParameterError(const Token *tok) { reportError(tok, Severity::error, "sizeofwithnumericparameter", "Using sizeof with a numeric constant as function " "argument might not be what you intended.\n" "It is unusual to use constant value with sizeof. For example, this code:\n" " int f() {\n" " return sizeof(10);\n" " }\n" " returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 10." ); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkSizeofForArrayParameter() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "sizeof ( %var% )") || Token::Match(tok, "sizeof %var%")) { unsigned short tokIdx = 1; if (tok->strAt(tokIdx) == "(") { ++tokIdx; } if (tok->tokAt(tokIdx)->varId() > 0) { const Variable *var = symbolDatabase->getVariableFromVarId(tok->tokAt(tokIdx)->varId()); if (var) { const Token *declTok = var->nameToken(); if (Token::simpleMatch(declTok->next(), "[")) { declTok = declTok->next()->link(); // multidimensional array while (Token::simpleMatch(declTok->next(), "[")) { declTok = declTok->next()->link(); } if (!(Token::Match(declTok->next(), "= %str%")) && !(Token::simpleMatch(declTok->next(), "= {")) && !(Token::simpleMatch(declTok->next(), ";"))) { if (Token::simpleMatch(declTok->next(), ",")) { declTok = declTok->next(); while (!Token::simpleMatch(declTok, ";")) { if (Token::simpleMatch(declTok, ")")) { sizeofForArrayParameterError(tok); break; } if (Token::Match(declTok, "(|[|{")) { declTok = declTok->link(); } declTok = declTok->next(); } } } if (Token::simpleMatch(declTok->next(), ")")) { sizeofForArrayParameterError(tok); } } } } } } } void CheckOther::sizeofForArrayParameterError(const Token *tok) { reportError(tok, Severity::error, "sizeofwithsilentarraypointer", "Using sizeof for array given as function argument " "returns the size of pointer.\n" "Giving array as function parameter and then using sizeof-operator for the array " "argument. In this case the sizeof-operator returns the size of pointer (in the " "system). It does not return the size of the whole array in bytes as might be " "expected. For example, this code:\n" " int f(char a[100]) {\n" " return sizeof(a);\n" " }\n" " returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 100 (the " "size of the array in bytes)." ); } void CheckOther::checkSizeofForStrncmpSize() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const char pattern1[] = "strncmp ( %any% , %any% , sizeof ( %var% ) )"; const char pattern2[] = "strncmp ( %any% , %any% , sizeof %var% )"; // danmar : this is inconclusive in case the size parameter is // sizeof(char *) by intention. if (!_settings->inconclusive) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, pattern1) || Token::Match(tok, pattern2)) { unsigned short tokIdx = 7; if (tok->strAt(tokIdx) == "(") ++tokIdx; const Token *tokVar = tok->tokAt(tokIdx); if (tokVar->varId() > 0) { const Variable *var = symbolDatabase->getVariableFromVarId(tokVar->varId()); if (var && var->nameToken()->strAt(-1) == "*") { sizeofForStrncmpError(tokVar); } } } } } void CheckOther::sizeofForStrncmpError(const Token *tok) { reportInconclusiveError(tok, Severity::warning, "strncmpLen", "Passing sizeof(pointer) as the last argument to strncmp.\n" "Passing a pointer to sizeof returns the size of the pointer, not " "the number of characters pointed to by that pointer. This " "means that only 4 or 8 (on 64-bit systems) characters are " "compared, which is probably not what was expected."); } //--------------------------------------------------------------------------- // switch (x) // { // case 2: // y = a; // <- this assignment is redundant // case 3: // y = b; // <- case 2 falls through and sets y twice // } //--------------------------------------------------------------------------- void CheckOther::checkRedundantAssignmentInSwitch() { const char switchPattern[] = "switch ( %any% ) { case"; const char breakPattern[] = "break|continue|return|exit|goto|throw"; const char functionPattern[] = "%var% ("; // Find the beginning of a switch. E.g.: // switch (var) { ... const Token *tok = Token::findmatch(_tokenizer->tokens(), switchPattern); while (tok) { // Check the contents of the switch statement std::map varsAssigned; std::map stringsCopied; int indentLevel = 0; for (const Token *tok2 = tok->tokAt(5); tok2; tok2 = tok2->next()) { if (tok2->str() == "{") { // Inside a conditional or loop. Don't mark variable accesses as being redundant. E.g.: // case 3: b = 1; // case 4: if (a) { b = 2; } // Doesn't make the b=1 redundant because it's conditional if (Token::Match(tok2->previous(), ")|else {") && tok2->link()) { const Token* endOfConditional = tok2->link(); for (const Token* tok3 = tok2; tok3 != endOfConditional; tok3 = tok3->next()) { if (tok3->varId() != 0) { varsAssigned.erase(tok3->varId()); stringsCopied.erase(tok3->varId()); } else if (Token::Match(tok3, functionPattern) || Token::Match(tok3, breakPattern)) { varsAssigned.clear(); if (tok3->str() != "strcpy" && tok3->str() != "strncpy") stringsCopied.clear(); } } tok2 = endOfConditional; } else ++ indentLevel; } else if (tok2->str() == "}") { -- indentLevel; // End of the switch block if (indentLevel < 0) break; } // Variable assignment. Report an error if it's assigned to twice before a break. E.g.: // case 3: b = 1; // <== redundant // case 4: b = 2; if (Token::Match(tok2->previous(), ";|{|}|: %var% = %any% ;") && tok2->varId() != 0) { std::map::iterator i = varsAssigned.find(tok2->varId()); if (i == varsAssigned.end()) varsAssigned[tok2->varId()] = tok2; else redundantAssignmentInSwitchError(i->second, i->second->str()); stringsCopied.erase(tok2->varId()); } // String copy. Report an error if it's copied to twice before a break. E.g.: // case 3: strcpy(str, "a"); // <== redundant // case 4: strcpy(str, "b"); else if (Token::Match(tok2->previous(), ";|{|}|: strcpy|strncpy ( %var% ,") && tok2->tokAt(2)->varId() != 0) { std::map::iterator i = stringsCopied.find(tok2->tokAt(2)->varId()); if (i == stringsCopied.end()) stringsCopied[tok2->tokAt(2)->varId()] = tok2->tokAt(2); else redundantStrcpyInSwitchError(i->second, i->second->str()); } // Not a simple assignment so there may be good reason if this variable is assigned to twice. E.g.: // case 3: b = 1; // case 4: b++; else if (tok2->varId() != 0) varsAssigned.erase(tok2->varId()); // Reset our record of assignments if there is a break or function call. E.g.: // case 3: b = 1; break; if (Token::Match(tok2, functionPattern) || Token::Match(tok2, breakPattern)) { varsAssigned.clear(); if (tok2->str() != "strcpy" && tok2->str() != "strncpy") stringsCopied.clear(); } } tok = Token::findmatch(tok->next(), switchPattern); } } void CheckOther::redundantAssignmentInSwitchError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "redundantAssignInSwitch", "Redundant assignment of \"" + varname + "\" in switch"); } void CheckOther::redundantStrcpyInSwitchError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "redundantStrcpyInSwitch", "Switch case fall-through. Redundant strcpy of \"" + varname + "\".\n" "Switch case fall-through. Redundant strcpy of \"" + varname + "\". The string is overwritten in a later case block."); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkSwitchCaseFallThrough() { if (!(_settings->isEnabled("style") && _settings->experimental)) return; const char switchPattern[] = "switch ("; const char breakPattern[] = "break|continue|return|exit|goto|throw"; // Find the beginning of a switch. E.g.: // switch (var) { ... const Token *tok = Token::findmatch(_tokenizer->tokens(), switchPattern); while (tok) { // Check the contents of the switch statement std::stack > ifnest; std::stack loopnest; std::stack scopenest; bool justbreak = true; bool firstcase = true; for (const Token *tok2 = tok->next()->link()->tokAt(2); tok2; tok2 = tok2->next()) { if (Token::simpleMatch(tok2, "if (")) { tok2 = tok2->next()->link()->next(); if (tok2->link() == NULL) { std::ostringstream errmsg; errmsg << "unmatched if in switch: " << tok2->linenr(); reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str()); break; } ifnest.push(std::make_pair(tok2->link(), false)); justbreak = false; } else if (Token::simpleMatch(tok2, "while (")) { tok2 = tok2->next()->link()->next(); // skip over "do { } while ( ) ;" case if (tok2->str() == "{") { if (tok2->link() == NULL) { std::ostringstream errmsg; errmsg << "unmatched while in switch: " << tok2->linenr(); reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str()); break; } loopnest.push(tok2->link()); } justbreak = false; } else if (Token::simpleMatch(tok2, "do {")) { tok2 = tok2->next(); if (tok2->link() == NULL) { std::ostringstream errmsg; errmsg << "unmatched do in switch: " << tok2->linenr(); reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str()); break; } loopnest.push(tok2->link()); justbreak = false; } else if (Token::simpleMatch(tok2, "for (")) { tok2 = tok2->next()->link()->next(); if (tok2->link() == NULL) { std::ostringstream errmsg; errmsg << "unmatched for in switch: " << tok2->linenr(); reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str()); break; } loopnest.push(tok2->link()); justbreak = false; } else if (Token::Match(tok2, switchPattern)) { // skip over nested switch, we'll come to that soon tok2 = tok2->next()->link()->next()->link(); } else if (Token::Match(tok2, breakPattern)) { if (loopnest.empty()) { justbreak = true; } tok2 = Token::findsimplematch(tok2, ";"); } else if (Token::Match(tok2, "case|default")) { if (!justbreak && !firstcase) { switchCaseFallThrough(tok2); } tok2 = Token::findsimplematch(tok2, ":"); justbreak = true; firstcase = false; } else if (tok2->str() == "{") { scopenest.push(tok2->link()); } else if (tok2->str() == "}") { if (!ifnest.empty() && tok2 == ifnest.top().first) { if (tok2->next()->str() == "else") { tok2 = tok2->tokAt(2); ifnest.pop(); if (tok2->link() == NULL) { std::ostringstream errmsg; errmsg << "unmatched if in switch: " << tok2->linenr(); reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str()); break; } ifnest.push(std::make_pair(tok2->link(), justbreak)); justbreak = false; } else { justbreak &= ifnest.top().second; ifnest.pop(); } } else if (!loopnest.empty() && tok2 == loopnest.top()) { loopnest.pop(); } else if (!scopenest.empty() && tok2 == scopenest.top()) { scopenest.pop(); } else { if (!ifnest.empty() || !loopnest.empty() || !scopenest.empty()) { std::ostringstream errmsg; errmsg << "unexpected end of switch: "; errmsg << "ifnest=" << ifnest.size(); if (!ifnest.empty()) errmsg << "," << ifnest.top().first->linenr(); errmsg << ", loopnest=" << loopnest.size(); if (!loopnest.empty()) errmsg << "," << loopnest.top()->linenr(); errmsg << ", scopenest=" << scopenest.size(); if (!scopenest.empty()) errmsg << "," << scopenest.top()->linenr(); reportError(_tokenizer->tokens(), Severity::debug, "debug", errmsg.str()); } // end of switch block break; } } else if (tok2->str() != ";") { justbreak = false; } } tok = Token::findmatch(tok->next(), switchPattern); } } void CheckOther::switchCaseFallThrough(const Token *tok) { reportError(tok, Severity::style, "switchCaseFallThrough", "Switch falls through case without comment"); } //--------------------------------------------------------------------------- // std::cout << std::cout; //--------------------------------------------------------------------------- void CheckOther::checkCoutCerrMisusage() { bool firstCout = false; unsigned int roundbraces = 0; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->str() == "(") ++roundbraces; else if (tok->str() == ")") { if (!roundbraces) break; --roundbraces; } if (roundbraces) continue; if (Token::Match(tok, "std :: cout|cerr")) { if (firstCout && tok->strAt(-1) == "<<" && tok->strAt(3) != ".") { coutCerrMisusageError(tok, tok->strAt(2)); firstCout = false; } else if (tok->strAt(3) == "<<") firstCout = true; } else if (firstCout && tok->str() == ";") firstCout = false; } } void CheckOther::coutCerrMisusageError(const Token* tok, const std::string& streamName) { reportError(tok, Severity::error, "coutCerrMisusage", "Invalid usage of output stream: '<< std::" + streamName + "'."); } //--------------------------------------------------------------------------- // int x = 1; // x = x; // <- redundant assignment to self // // int y = y; // <- redundant initialization to self //--------------------------------------------------------------------------- void CheckOther::checkSelfAssignment() { if (!_settings->isEnabled("style")) return; // POD variables.. std::set pod; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->isStandardType() && Token::Match(tok->tokAt(2), "[,);]") && tok->next()->varId()) pod.insert(tok->next()->varId()); } const char selfAssignmentPattern[] = "%var% = %var% ;|=|)"; const Token *tok = Token::findmatch(_tokenizer->tokens(), selfAssignmentPattern); while (tok) { if (Token::Match(tok->previous(), "[;{}]") && tok->varId() && tok->varId() == tok->tokAt(2)->varId() && pod.find(tok->varId()) != pod.end()) { bool err = true; // no false positive for 'x = x ? x : 1;' // it is simplified to 'if (x) { x=x; } else { x=1; }'. The simplification // always write all tokens on 1 line (even if the statement is several lines), so // check if the linenr is the same for all the tokens. if (Token::Match(tok->tokAt(-2), ") { %var% = %var% ; } else { %varid% =", tok->varId())) { // Find the 'if' token const Token *tokif = tok->linkAt(-2)->previous(); // find the '}' that terminates the 'else'-block const Token *else_end = tok->linkAt(6); if (tokif && else_end && tokif->linenr() == else_end->linenr()) err = false; } if (err) selfAssignmentError(tok, tok->str()); } tok = Token::findmatch(tok->next(), selfAssignmentPattern); } } void CheckOther::selfAssignmentError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "selfAssignment", "Redundant assignment of \"" + varname + "\" to itself"); } //--------------------------------------------------------------------------- // int a = 1; // assert(a = 2); // <- assert should not have a side-effect //--------------------------------------------------------------------------- void CheckOther::checkAssignmentInAssert() { if (!_settings->isEnabled("style")) return; const char assertPattern[] = "assert ( %any%"; const Token *tok = Token::findmatch(_tokenizer->tokens(), assertPattern); const Token *endTok = tok ? tok->next()->link() : NULL; while (tok && endTok) { const Token* varTok = Token::findmatch(tok->tokAt(2), "%var% --|++|+=|-=|*=|/=|&=|^=|=", endTok); if (varTok) { assignmentInAssertError(tok, varTok->str()); } else if (NULL != (varTok = Token::findmatch(tok->tokAt(2), "--|++ %var%", endTok))) { assignmentInAssertError(tok, varTok->strAt(1)); } tok = Token::findmatch(endTok->next(), assertPattern); endTok = tok ? tok->next()->link() : NULL; } } void CheckOther::assignmentInAssertError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "assignmentInAssert", "Assert statement modifies '" + varname + "'.\n" "Variable '" + varname + "' is modified insert assert statement. " "Assert statements are removed from release builds so the code inside " "assert statement is not run. If the code is needed also in release " "builds this is a bug."); } //--------------------------------------------------------------------------- // if ((x != 1) || (x != 3)) // expression always true // if ((x == 1) && (x == 3)) // expression always false // if ((x < 1) && (x > 3)) // expression always false // if ((x > 3) || (x < 10)) // expression always true // if ((x > 5) && (x != 1)) // second comparison always true // // Check for suspect logic for an expression consisting of 2 comparison // expressions with a shared variable and constants and a logical operator // between them. // // Suggest a different logical operator when the logical operator between // the comparisons is probably wrong. // // Inform that second comparison is always true when first comparison is true. //--------------------------------------------------------------------------- void CheckOther::checkIncorrectLogicOperator() { if (!_settings->isEnabled("style")) return; const char conditionPattern[] = "if|while ("; const Token *tok = Token::findmatch(_tokenizer->tokens(), conditionPattern); const Token *endTok = tok ? tok->next()->link() : NULL; while (tok && endTok) { // Find a pair of comparison expressions with or without parenthesis // with a shared variable and constants and with a logical operator between them. // e.g. if (x != 3 || x != 4) const Token *logicTok = NULL, *term1Tok = NULL, *term2Tok = NULL; const Token *op1Tok = NULL, *op2Tok = NULL, *op3Tok = NULL, *nextTok = NULL; if (NULL != (logicTok = Token::findmatch(tok, "( %any% !=|==|<|>|>=|<= %any% ) &&|%oror% ( %any% !=|==|<|>|>=|<= %any% ) %any%", endTok))) { term1Tok = logicTok->next(); term2Tok = logicTok->tokAt(7); op1Tok = logicTok->tokAt(2); op2Tok = logicTok->tokAt(5); op3Tok = logicTok->tokAt(8); nextTok = logicTok->tokAt(11); } else if (NULL != (logicTok = Token::findmatch(tok, "%any% !=|==|<|>|>=|<= %any% &&|%oror% %any% !=|==|<|>|>=|<= %any% %any%", endTok))) { term1Tok = logicTok; term2Tok = logicTok->tokAt(4); op1Tok = logicTok->next(); op2Tok = logicTok->tokAt(3); op3Tok = logicTok->tokAt(5); nextTok = logicTok->tokAt(7); } if (logicTok) { // Find the common variable and the two different-valued constants unsigned int variableTested = 0; std::string firstConstant, secondConstant; bool varFirst1, varFirst2; unsigned int varId; const Token *varTok = NULL; if (Token::Match(term1Tok, "%var% %any% %num%")) { varTok = term1Tok; varId = varTok->varId(); if (!varId) { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } varFirst1 = true; firstConstant = term1Tok->strAt(2); } else if (Token::Match(term1Tok, "%num% %any% %var%")) { varTok = term1Tok->tokAt(2); varId = varTok->varId(); if (!varId) { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } varFirst1 = false; firstConstant = term1Tok->str(); } else { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } if (Token::Match(term2Tok, "%var% %any% %num%")) { const unsigned int varId2 = term2Tok->varId(); if (!varId2 || varId != varId2) { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } varFirst2 = true; secondConstant = term2Tok->strAt(2); variableTested = varId; } else if (Token::Match(term2Tok, "%num% %any% %var%")) { const unsigned int varId2 = term1Tok->tokAt(2)->varId(); if (!varId2 || varId != varId2) { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } varFirst2 = false; secondConstant = term2Tok->str(); variableTested = varId; } else { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } if (variableTested == 0 || firstConstant.empty() || secondConstant.empty()) { tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; continue; } enum Position { First, Second, NA }; enum Relation { Equal, NotEqual, Less, LessEqual, More, MoreEqual }; enum LogicError { Exclusion, AlwaysTrue, AlwaysFalse, AlwaysFalseOr }; static const struct Condition { const char *before; Position position1; const char *op1TokStr; const char *op2TokStr; Position position2; const char *op3TokStr; const char *after; Relation relation; LogicError error; } conditions[] = { { "!!&&", NA, "!=", "||", NA, "!=", "!!&&", NotEqual, Exclusion }, // (x != 1) || (x != 3) <- always true { "(", NA, "==", "&&", NA, "==", ")", NotEqual, AlwaysFalseOr }, // (x == 1) && (x == 3) <- always false { "(", First, "<", "&&", First, ">", ")", LessEqual, AlwaysFalseOr }, // (x < 1) && (x > 3) <- always false { "(", First, ">", "&&", First, "<", ")", MoreEqual, AlwaysFalseOr }, // (x > 3) && (x < 1) <- always false { "(", Second, ">", "&&", First, ">", ")", LessEqual, AlwaysFalseOr }, // (1 > x) && (x > 3) <- always false { "(", First, ">", "&&", Second, ">", ")", MoreEqual, AlwaysFalseOr }, // (x > 3) && (1 > x) <- always false { "(", First, "<", "&&", Second, "<", ")", LessEqual, AlwaysFalseOr }, // (x < 1) && (3 < x) <- always false { "(", Second, "<", "&&", First, "<", ")", MoreEqual, AlwaysFalseOr }, // (3 < x) && (x < 1) <- always false { "(", Second, ">", "&&", Second, "<", ")", LessEqual, AlwaysFalseOr }, // (1 > x) && (3 < x) <- always false { "(", Second, "<", "&&", Second, ">", ")", MoreEqual, AlwaysFalseOr }, // (3 < x) && (1 > x) <- always false { "(", First , ">|>=", "||", First, "<|<=", ")", Less, Exclusion }, // (x > 3) || (x < 10) <- always true { "(", First , "<|<=", "||", First, ">|>=", ")", More, Exclusion }, // (x < 10) || (x > 3) <- always true { "(", Second, "<|<=", "||", First, "<|<=", ")", Less, Exclusion }, // (3 < x) || (x < 10) <- always true { "(", First, "<|<=", "||", Second, "<|<=", ")", More, Exclusion }, // (x < 10) || (3 < x) <- always true { "(", First, ">|>=", "||", Second, ">|>=", ")", Less, Exclusion }, // (x > 3) || (10 > x) <- always true { "(", Second, ">|>=", "||", First, ">|>=", ")", More, Exclusion }, // (10 > x) || (x > 3) <- always true { "(", Second, "<|<=", "||", Second, ">|<=", ")", Less, Exclusion }, // (3 < x) || (10 > x) <- always true { "(", Second, ">|>=", "||", Second, "<|<=", ")", More, Exclusion }, // (10 > x) || (3 < x) <- always true { "(", First, ">", "&&", NA, "!=", ")", More, AlwaysTrue }, // (x > 5) && (x != 1) <- second expression always true { "(", Second, "<", "&&", NA, "!=", ")", More, AlwaysTrue }, // (5 < x) && (x != 1) <- second expression always true { "(", First, ">", "&&", NA, "==", ")", More, AlwaysFalse }, // (x > 5) && (x == 1) <- second expression always false { "(", Second, "<", "&&", NA, "==", ")", More, AlwaysFalse }, // (5 < x) && (x == 1) <- second expression always false }; for (unsigned int i = 0; i < (sizeof(conditions) / sizeof(conditions[0])); i++) { if (!((conditions[i].position1 == NA) || (((conditions[i].position1 == First) && varFirst1) || ((conditions[i].position1 == Second) && !varFirst1)))) continue; if (!((conditions[i].position2 == NA) || (((conditions[i].position2 == First) && varFirst2) || ((conditions[i].position2 == Second) && !varFirst2)))) continue; if (!Token::Match(op1Tok, conditions[i].op1TokStr)) continue; if (!Token::Match(op2Tok, conditions[i].op2TokStr)) continue; if (!Token::Match(op3Tok, conditions[i].op3TokStr)) continue; if (!Token::Match(logicTok->previous(), conditions[i].before)) continue; if (!Token::Match(nextTok, conditions[i].after)) continue; if ((conditions[i].relation == Equal && MathLib::isEqual(firstConstant, secondConstant)) || (conditions[i].relation == NotEqual && MathLib::isNotEqual(firstConstant, secondConstant)) || (conditions[i].relation == Less && MathLib::isLess(firstConstant, secondConstant)) || (conditions[i].relation == LessEqual && MathLib::isLessEqual(firstConstant, secondConstant)) || (conditions[i].relation == More && MathLib::isGreater(firstConstant, secondConstant)) || (conditions[i].relation == MoreEqual && MathLib::isGreaterEqual(firstConstant, secondConstant))) { if (conditions[i].error == Exclusion || conditions[i].error == AlwaysFalseOr) incorrectLogicOperatorError(term1Tok, conditions[i].error == Exclusion); else { std::string text("When " + varTok->str() + " is greater than " + firstConstant + ", the comparison " + varTok->str() + " " + conditions[i].op3TokStr + " " + secondConstant + " is always " + (conditions[i].error == AlwaysTrue ? "true." : "false.")); secondAlwaysTrueFalseWhenFirstTrueError(term1Tok, text); } } } } tok = Token::findmatch(endTok->next(), conditionPattern); endTok = tok ? tok->next()->link() : NULL; } } void CheckOther::incorrectLogicOperatorError(const Token *tok, bool always) { if (always) reportError(tok, Severity::warning, "incorrectLogicOperator", "Mutual exclusion over || always evaluates to true. Did you intend to use && instead?"); else reportError(tok, Severity::warning, "incorrectLogicOperator", "Expression always evaluates to false. Did you intend to use || instead?"); } void CheckOther::secondAlwaysTrueFalseWhenFirstTrueError(const Token *tok, const std::string &truefalse) { reportError(tok, Severity::style, "secondAlwaysTrueFalseWhenFirstTrue", truefalse); } //--------------------------------------------------------------------------- // try {} catch (std::exception err) {} <- Should be "std::exception& err" //--------------------------------------------------------------------------- void CheckOther::checkCatchExceptionByValue() { if (!_settings->isEnabled("style")) return; const char catchPattern[] = "} catch ("; const Token *tok = Token::findmatch(_tokenizer->tokens(), catchPattern); const Token *endTok = tok ? tok->linkAt(2) : NULL; while (tok && endTok) { // Find a pass-by-value declaration in the catch(), excluding basic types // e.g. catch (std::exception err) const Token *tokType = Token::findmatch(tok, "%type% %var% )", endTok); if (tokType && !tokType->isStandardType()) { catchExceptionByValueError(tokType); } tok = Token::findmatch(endTok->next(), catchPattern); endTok = tok ? tok->linkAt(2) : NULL; } } void CheckOther::catchExceptionByValueError(const Token *tok) { reportError(tok, Severity::style, "catchExceptionByValue", "Exception should be caught by reference.\n" "The exception is caught as a value. It could be caught " "as a (const) reference which is usually recommended in C++."); } //--------------------------------------------------------------------------- // strtol(str, 0, radix) <- radix must be 0 or 2-36 //--------------------------------------------------------------------------- void CheckOther::invalidFunctionUsage() { // strtol and strtoul.. for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (!Token::Match(tok, "strtol|strtoul (")) continue; // Locate the third parameter of the function call.. unsigned int param = 1; for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { if (tok2->str() == "(") tok2 = tok2->link(); else if (tok2->str() == ")") break; else if (tok2->str() == ",") { ++param; if (param == 3) { if (Token::Match(tok2, ", %num% )")) { const MathLib::bigint radix = MathLib::toLongNumber(tok2->next()->str()); if (!(radix == 0 || (radix >= 2 && radix <= 36))) { dangerousUsageStrtolError(tok2); } } break; } } } } // sprintf|snprintf overlapping data for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Get variable id of target buffer.. unsigned int varid = 0; if (Token::Match(tok, "sprintf|snprintf ( %var% ,")) varid = tok->tokAt(2)->varId(); else if (Token::Match(tok, "sprintf|snprintf ( %var% . %var% ,")) varid = tok->tokAt(4)->varId(); if (varid == 0) continue; // goto "," const Token *tok2 = tok->tokAt(3); while (tok2->str() != ",") tok2 = tok2->next(); tok2 = tok2->next(); // Jump behind "," if (tok->str() == "snprintf") { // Jump over second parameter for snprintf tok2 = tok2->nextArgument(); if (!tok2) continue; } // is any source buffer overlapping the target buffer? do { if (Token::Match(tok2, "%varid% [,)]", varid)) { sprintfOverlappingDataError(tok2->next(), tok2->next()->str()); break; } } while (NULL != (tok2 = tok2->nextArgument())); } } void CheckOther::dangerousUsageStrtolError(const Token *tok) { reportError(tok, Severity::error, "dangerousUsageStrtol", "Invalid radix in call to strtol or strtoul. Must be 0 or 2-36"); } void CheckOther::sprintfOverlappingDataError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "sprintfOverlappingData", "Undefined behavior: variable is used as parameter and destination in s[n]printf().\n" "The variable '" + varname + "' is used both as a parameter and as a destination in " "s[n]printf(). The origin and destination buffers overlap. Quote from glibc (C-library) " "documentation (http://www.gnu.org/software/libc/manual/html_mono/libc.html#Formatted-Output-Functions): " "'If copying takes place between objects that overlap as a result of a call " "to sprintf() or snprintf(), the results are undefined.'"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::invalidScanf() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { const Token *formatToken = 0; if (Token::Match(tok, "scanf|vscanf ( %str% ,")) formatToken = tok->tokAt(2); else if (Token::Match(tok, "fscanf|vfscanf (")) { const Token* nextArg = tok->tokAt(2)->nextArgument(); if (nextArg && Token::Match(nextArg, "%str%")) formatToken = nextArg; else continue; } else continue; bool format = false; // scan the string backwards, so we dont need to keep states const std::string &formatstr(formatToken->str()); for (unsigned int i = 1; i < formatstr.length(); i++) { if (formatstr[i] == '%') format = !format; else if (!format) continue; else if (std::isdigit(formatstr[i])) { format = false; } else if (std::isalpha(formatstr[i])) { invalidScanfError(tok); format = false; } } } } void CheckOther::invalidScanfError(const Token *tok) { reportError(tok, Severity::warning, "invalidscanf", "scanf without field width limits can crash with huge input data\n" "scanf without field width limits can crash with huge input data. To fix this error " "message add a field width specifier:\n" " %s => %20s\n" " %i => %3i\n" "\n" "Sample program that can crash:\n" "\n" "#include \n" "int main()\n" "{\n" " int a;\n" " scanf(\"%i\", &a);\n" " return 0;\n" "}\n" "\n" "To make it crash:\n" "perl -e 'print \"5\"x2100000' | ./a.out"); } //--------------------------------------------------------------------------- // printf("%u", "xyz"); // Wrong argument type. TODO. // printf("%u%s", 1); // Too few arguments // printf("", 1); // Too much arguments //--------------------------------------------------------------------------- void CheckOther::checkWrongPrintfScanfArguments() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (!tok->isName()) continue; const Token* argListTok = 0; // Points to first va_list argument std::string formatString; if (Token::Match(tok, "printf|scanf ( %str%")) { formatString = tok->strAt(2); if (tok->strAt(3) == ",") { argListTok = tok->tokAt(4); } else if (tok->strAt(3) == ")") { argListTok = 0; } else { continue; } } else if (Token::Match(tok, "sprintf|fprintf|sscanf|fscanf ( %any%")) { const Token* formatStringTok = tok->tokAt(2)->nextArgument(); // Find second parameter (format string) if (Token::Match(formatStringTok, "%str% ,")) { argListTok = formatStringTok->nextArgument(); // Find third parameter (first argument of va_args) formatString = formatStringTok->str(); } else if (Token::Match(formatStringTok, "%str% )")) { argListTok = 0; // Find third parameter (first argument of va_args) formatString = formatStringTok->str(); } else { continue; } } else if (Token::Match(tok, "snprintf|fnprintf ( %any%")) { const Token* formatStringTok = tok->tokAt(2); for (int i = 0; i < 2 && formatStringTok; i++) { formatStringTok = formatStringTok->nextArgument(); // Find third parameter (format string) } if (Token::Match(formatStringTok, "%str% ,")) { argListTok = formatStringTok->nextArgument(); // Find fourth parameter (first argument of va_args) formatString = formatStringTok->str(); } if (Token::Match(formatStringTok, "%str% )")) { argListTok = 0; // Find fourth parameter (first argument of va_args) formatString = formatStringTok->str(); } else { continue; } } else { continue; } // Count format string parameters.. unsigned int numFormat = 0; bool percent = false; for (std::string::iterator i = formatString.begin(); i != formatString.end(); ++i) { if (*i == '%') { percent = !percent; } else if (percent && *i == '[') { while (i != formatString.end()) { if (*i == ']') { numFormat++; percent = false; break; } ++i; } if (i == formatString.end()) break; } else if (percent) { while (!std::isalpha(*i) && i != formatString.end()) { if (*i == '*') numFormat++; ++i; } if (i == formatString.end()) break; if (*i != 'm') // %m is a non-standard extension that requires no parameter numFormat++; percent = false; } } // Count printf/scanf parameters.. unsigned int numFunction = 0; while (argListTok) { // TODO: Perform type checks numFunction++; argListTok = argListTok->nextArgument(); // Find next argument } // Mismatching number of parameters => warning if (numFormat != numFunction) wrongPrintfScanfArgumentsError(tok, tok->str(), numFormat, numFunction); } } void CheckOther::wrongPrintfScanfArgumentsError(const Token* tok, const std::string &functionName, unsigned int numFormat, unsigned int numFunction) { std::ostringstream errmsg; errmsg << functionName << " format string has " << numFormat << " parameters but " << (numFormat > numFunction ? "only " : "") << numFunction << " are given"; reportError(tok, numFormat > numFunction ? Severity::error : Severity::warning, "wrongPrintfScanfArgs", errmsg.str()); } //--------------------------------------------------------------------------- // if (!x==3) <- Probably meant to be "x!=3" //--------------------------------------------------------------------------- void CheckOther::checkComparisonOfBoolWithInt() { if (!_settings->isEnabled("style")) return; std::map boolvars; // Contains all declarated standard type variables and indicates whether its a bool or not. for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "[{};(,] %type% %var% [;=,)]") && tok->next()->isStandardType()) { // Declaration of standard type variable boolvars[tok->tokAt(2)->varId()] = (tok->strAt(1) == "bool"); } else if (Token::Match(tok, "%var% >|>=|==|!=|<=|< %num%")) { // Comparing variable with number const Token *varTok = tok; const Token *numTok = tok->tokAt(2); std::map::const_iterator iVar = boolvars.find(varTok->varId()); if (iVar != boolvars.end() && iVar->second && // Variable has to be a boolean ((tok->strAt(1) != "==" && tok->strAt(1) != "!=") || (MathLib::toLongNumber(numTok->str()) != 0 && MathLib::toLongNumber(numTok->str()) != 1))) { // == 0 and != 0 are allowed, for C also == 1 and != 1 comparisonOfBoolWithIntError(varTok, numTok->str()); } } else if (Token::Match(tok, "%num% >|>=|==|!=|<=|< %var%")) { // Comparing number with variable const Token *varTok = tok->tokAt(2); const Token *numTok = tok; std::map::const_iterator iVar = boolvars.find(varTok->varId()); if (iVar != boolvars.end() && iVar->second && // Variable has to be a boolean ((tok->strAt(1) != "==" && tok->strAt(1) != "!=") || (MathLib::toLongNumber(numTok->str()) != 0 && MathLib::toLongNumber(numTok->str()) != 1))) { // == 0 and != 0 are allowed, for C also == 1 and != 1 comparisonOfBoolWithIntError(varTok, numTok->str()); } } else if (Token::Match(tok, "true|false >|>=|==|!=|<=|< %var%")) { // Comparing boolean constant with variable const Token *varTok = tok->tokAt(2); const Token *constTok = tok; std::map::const_iterator iVar = boolvars.find(varTok->varId()); if (iVar != boolvars.end() && !iVar->second) { // Variable has to be of non-boolean standard type comparisonOfBoolWithIntError(varTok, constTok->str()); } } else if (Token::Match(tok, "%var% >|>=|==|!=|<=|< true|false")) { // Comparing variable with boolean constant const Token *varTok = tok; const Token *constTok = tok->tokAt(2); std::map::const_iterator iVar = boolvars.find(varTok->varId()); if (iVar != boolvars.end() && !iVar->second) { // Variable has to be of non-boolean standard type comparisonOfBoolWithIntError(varTok, constTok->str()); } } else if (Token::Match(tok, "%var% >|>=|==|!=|<=|< %var%")) { // Comparing two variables, one of them boolean, one of them integer const Token *var1Tok = tok->tokAt(2); const Token *var2Tok = tok; std::map::const_iterator iVar1 = boolvars.find(var1Tok->varId()); std::map::const_iterator iVar2 = boolvars.find(var2Tok->varId()); if (iVar1 != boolvars.end() && iVar2 != boolvars.end()) { if (iVar1->second && !iVar2->second) // Comparing boolean with non-bool standard type comparisonOfBoolWithIntError(var2Tok, var1Tok->str()); else if (!iVar1->second && iVar2->second) // Comparing non-bool standard type with boolean comparisonOfBoolWithIntError(var2Tok, var2Tok->str()); } } else if (Token::Match(tok, "( ! %var% ==|!= %num% )")) { const Token *numTok = tok->tokAt(4); if (numTok && numTok->str() != "0" && numTok->str() != "1") { comparisonOfBoolWithIntError(numTok, "!"+tok->strAt(2)); } } else if (Token::Match(tok, "( %num% ==|!= ! %var% )")) { const Token *numTok = tok->next(); if (numTok && numTok->str() != "0" && numTok->str() != "1") { comparisonOfBoolWithIntError(numTok, "!"+tok->strAt(4)); } } } } void CheckOther::comparisonOfBoolWithIntError(const Token *tok, const std::string &expression) { reportError(tok, Severity::warning, "comparisonOfBoolWithInt", "Comparison of a boolean with integer that is neither 1 nor 0\n" "The expression \"" + expression + "\" is of type 'bool' " "and it is compared against a integer value that is " "neither 1 nor 0."); } //--------------------------------------------------------------------------- // switch (x) // { // case 2: // y = a; // break; // break; // <- Redundant break // case 3: // y = b; // } //--------------------------------------------------------------------------- void CheckOther::checkDuplicateBreak() { if (!_settings->isEnabled("style")) return; const char breakPattern[] = "break|continue ; break|continue ;"; // Find consecutive break or continue statements. e.g.: // break; break; const Token *tok = Token::findmatch(_tokenizer->tokens(), breakPattern); while (tok) { duplicateBreakError(tok); tok = Token::findmatch(tok->next(), breakPattern); } } void CheckOther::duplicateBreakError(const Token *tok) { reportError(tok, Severity::style, "duplicateBreak", "Consecutive break or continue statements are unnecessary\n" "The second of the two statements can never be executed, and so should be removed\n"); } //--------------------------------------------------------------------------- // Check for unsigned divisions //--------------------------------------------------------------------------- void CheckOther::checkUnsignedDivision() { if (!_settings->isEnabled("style")) return; // Check for "ivar / uvar" and "uvar / ivar" std::map varsign; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "[{};(,] %type% %var% [;=,)]")) { if (tok->next()->isUnsigned()) varsign[tok->tokAt(2)->varId()] = 'u'; else varsign[tok->tokAt(2)->varId()] = 's'; } else if (!Token::Match(tok, "[).]") && Token::Match(tok->next(), "%var% / %num%")) { if (tok->strAt(3)[0] == '-') { char sign1 = varsign[tok->next()->varId()]; if (sign1 == 'u') { udivError(tok->next()); } } } else if (Token::Match(tok, "(|[|=|%op% %num% / %var%")) { if (tok->strAt(1)[0] == '-') { char sign2 = varsign[tok->tokAt(3)->varId()]; if (sign2 == 'u') { udivError(tok->next()); } } } } } void CheckOther::udivError(const Token *tok) { reportError(tok, Severity::error, "udivError", "Unsigned division. The result will be wrong."); } //--------------------------------------------------------------------------- // memset(p, y, 0 /* bytes to fill */) <- 2nd and 3rd arguments inverted //--------------------------------------------------------------------------- void CheckOther::checkMemsetZeroBytes() { for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "memset (")) { const Token* lastParamTok = tok->next()->link()->previous(); if (lastParamTok->str() == "0") memsetZeroBytesError(tok, tok->strAt(2)); } } } void CheckOther::memsetZeroBytesError(const Token *tok, const std::string &varname) { const std::string summary("memset() called to fill 0 bytes of \'" + varname + "\'"); const std::string verbose(summary + ". Second and third arguments might be inverted."); reportError(tok, Severity::warning, "memsetZeroBytes", summary + "\n" + verbose); } //--------------------------------------------------------------------------- // Check scope of variables.. //--------------------------------------------------------------------------- void CheckOther::checkVariableScope() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { // only check functions if (scope->type != Scope::eFunction) continue; // Walk through all tokens.. unsigned int indentlevel = 0; for (const Token *tok = scope->classStart; tok; tok = tok->next()) { // Skip function local class and struct declarations.. if ((tok->str() == "class") || (tok->str() == "struct") || (tok->str() == "union")) { for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) { if (tok2->str() == "{") { tok = tok2->link(); break; } if (Token::Match(tok2, "[,);]")) { break; } } if (! tok) break; } else if (tok->str() == "{") { ++indentlevel; } else if (tok->str() == "}") { if (!indentlevel) break; --indentlevel; } if (indentlevel > 0 && Token::Match(tok, "[{};]")) { // First token of statement.. const Token *tok1 = tok->next(); if (! tok1) continue; if ((tok1->str() == "return") || (tok1->str() == "throw") || (tok1->str() == "delete") || (tok1->str() == "goto") || (tok1->str() == "else")) continue; // Variable declaration? if (Token::Match(tok1, "%type% %var% ; %var% = %num% ;")) { // Tokenizer modify "int i = 0;" to "int i; i = 0;", // so to handle this situation we just skip // initialization (see ticket #272). const unsigned int firstVarId = tok1->next()->varId(); const unsigned int secondVarId = tok1->tokAt(3)->varId(); if (firstVarId > 0 && firstVarId == secondVarId) { lookupVar(tok1->tokAt(6), tok1->strAt(1)); } } else if (tok1->isStandardType() && Token::Match(tok1, "%type% %var% [;=]")) { lookupVar(tok1, tok1->strAt(1)); } } } } } void CheckOther::lookupVar(const Token *tok1, const std::string &varname) { const Token *tok = tok1; // Skip the variable declaration.. while (tok && tok->str() != ";") tok = tok->next(); // Check if the variable is used in this indentlevel.. bool used1 = false; // used in one sub-scope -> reducable bool used2 = false; // used in more sub-scopes -> not reducable unsigned int indentlevel = 0; int parlevel = 0; bool for_or_while = false; // is sub-scope a "for/while/etc". anything that is not "if" while (tok) { if (tok->str() == "{") { if (tok->strAt(-1) == "=") { if (Token::findmatch(tok, varname.c_str(), tok->link())) { return; } tok = tok->link(); } else ++indentlevel; } else if (tok->str() == "}") { if (indentlevel == 0) break; --indentlevel; if (indentlevel == 0) { if (for_or_while && used2) return; used2 |= used1; used1 = false; } } else if (tok->str() == "(") { ++parlevel; } else if (tok->str() == ")") { --parlevel; } // Bail out if references are used else if (Token::simpleMatch(tok, (std::string("& ") + varname).c_str())) { return; } else if (tok->str() == varname) { if (indentlevel == 0) return; used1 = true; if (for_or_while && !Token::simpleMatch(tok->next(), "=")) used2 = true; if (used1 && used2) return; } else if (indentlevel == 0) { // %unknown% ( %any% ) { // If %unknown% is anything except if, we assume // that it is a for or while loop or a macro hiding either one if (Token::simpleMatch(tok->next(), "(") && Token::simpleMatch(tok->next()->link(), ") {")) { if (tok->str() != "if") for_or_while = true; } else if (Token::simpleMatch(tok, "do {")) for_or_while = true; // possible unexpanded macro hiding for/while.. else if (tok->str() != "else" && Token::Match(tok->previous(), "[;{}] %type% {")) { for_or_while = true; } if (parlevel == 0 && (tok->str() == ";")) for_or_while = false; } tok = tok->next(); } // Warning if this variable: // * not used in this indentlevel // * used in lower indentlevel if (used1 || used2) variableScopeError(tok1, varname); } void CheckOther::variableScopeError(const Token *tok, const std::string &varname) { reportError(tok, Severity::style, "variableScope", "The scope of the variable '" + varname + "' can be reduced\n" "The scope of the variable '" + varname + "' can be reduced. Warning: It can be unsafe " "to fix this message. Be careful. Especially when there are inner loops. Here is an " "example where cppcheck will write that the scope for 'i' can be reduced:\n" "void f(int x)\n" "{\n" " int i = 0;\n" " if (x) {\n" " // it's safe to move 'int i = 0' here\n" " for (int n = 0; n < 10; ++n) {\n" " // it is possible but not safe to move 'int i = 0' here\n" " do_something(&i);\n" " }\n" " }\n" "}\n" "When you see this message it is always safe to reduce the variable scope 1 level."); } //--------------------------------------------------------------------------- // Check for constant function parameters //--------------------------------------------------------------------------- void CheckOther::checkConstantFunctionParameter() { if (!_settings->isEnabled("performance")) return; const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase(); for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // TODO: False negatives. This pattern only checks for string. // Investigate if there are other classes in the std // namespace and add them to the pattern. There are // streams for example (however it seems strange with // const stream parameter). if (Token::Match(tok, "[,(] const std :: string %var% [,)]")) { passedByValueError(tok, tok->strAt(5)); } else if (Token::Match(tok, "[,(] const std :: %type% < %type% > %var% [,)]")) { passedByValueError(tok, tok->strAt(8)); } else if (Token::Match(tok, "[,(] const std :: %type% < std :: %type% > %var% [,)]")) { passedByValueError(tok, tok->strAt(10)); } else if (Token::Match(tok, "[,(] const std :: %type% < std :: %type% , std :: %type% > %var% [,)]")) { passedByValueError(tok, tok->strAt(14)); } else if (Token::Match(tok, "[,(] const std :: %type% < %type% , std :: %type% > %var% [,)]")) { passedByValueError(tok, tok->strAt(12)); } else if (Token::Match(tok, "[,(] const std :: %type% < std :: %type% , %type% > %var% [,)]")) { passedByValueError(tok, tok->strAt(12)); } else if (Token::Match(tok, "[,(] const std :: %type% < %type% , %type% > %var% [,)]")) { passedByValueError(tok, tok->strAt(10)); } else if (Token::Match(tok, "[,(] const %type% %var% [,)]")) { // Check if type is a struct or class. if (symbolDatabase->isClassOrStruct(tok->strAt(2))) { passedByValueError(tok, tok->strAt(3)); } } } } void CheckOther::passedByValueError(const Token *tok, const std::string &parname) { reportError(tok, Severity::performance, "passedByValue", "Function parameter '" + parname + "' should be passed by reference.\n" "Parameter '" + parname + "' is passed as a value. It could be passed " "as a (const) reference which is usually faster and recommended in C++."); } //--------------------------------------------------------------------------- // Check usage of char variables.. //--------------------------------------------------------------------------- void CheckOther::checkCharVariable() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Declaring the variable.. if (Token::Match(tok, "[{};(,] const| char *| const| %var% [;=,)]") || Token::Match(tok, "[{};(,] const| char %var% [")) { // goto 'char' token tok = tok->next(); if (tok->str() == "const") tok = tok->next(); // Check for unsigned char if (tok->isUnsigned()) continue; // Set tok to point to the variable name tok = tok->next(); const bool isPointer(tok->str() == "*" || tok->strAt(1) == "["); if (tok->str() == "*") tok = tok->next(); if (tok->str() == "const") tok = tok->next(); const unsigned int varid = tok->varId(); if (!varid) continue; // Check usage of char variable.. unsigned int indentlevel = 0; for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == "{") ++indentlevel; else if (tok2->str() == "}") { if (!indentlevel) break; --indentlevel; } if (!isPointer) { if ((tok2->str() != ".") && Token::Match(tok2->next(), "%var% [ %varid% ]", varid)) { charArrayIndexError(tok2->next()); break; } } if (Token::Match(tok2, "[;{}] %var% = %any% [&|] %any% ;")) { // is the char variable used in the calculation? if (tok2->tokAt(3)->varId() != tok->varId() && tok2->tokAt(5)->varId() != tok->varId()) continue; // it's ok with a bitwise and where the other operand is 0xff or less.. if (tok2->strAt(4) == "&") { if (tok2->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok2->strAt(3))) continue; if (tok2->tokAt(5)->isNumber() && MathLib::isGreater("0x100", tok2->strAt(5))) continue; } // is the result stored in a short|int|long? const Variable *var = symbolDatabase->getVariableFromVarId(tok2->next()->varId()); if (!(var && Token::Match(var->typeEndToken(), "short|int|long"))) continue; // This is an error.. charBitOpError(tok2); break; } if (isPointer && Token::Match(tok2, "[;{}] %var% = %any% [&|] ( * %varid% ) ;", tok->varId())) { // it's ok with a bitwise and where the other operand is 0xff or less.. if (tok2->strAt(4) == "&" && tok2->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok2->strAt(3))) continue; // is the result stored in a short|int|long? const Variable *var = symbolDatabase->getVariableFromVarId(tok2->next()->varId()); if (!(var && Token::Match(var->typeEndToken(), "short|int|long"))) continue; // This is an error.. charBitOpError(tok2); break; } } } } } void CheckOther::charArrayIndexError(const Token *tok) { reportError(tok, Severity::warning, "charArrayIndex", "Using char type as array index\n" "Using signed char type as array index. If the value " "can be greater than 127 there will be a buffer overflow " "(because of sign extension)."); } void CheckOther::charBitOpError(const Token *tok) { reportError(tok, Severity::warning, "charBitOp", "When using char variables in bit operations, sign extension can generate unexpected results.\n" "When using char variables in bit operations, sign extension can generate unexpected results. For example:\n" " char c = 0x80;\n" " int i = 0 | c;\n" " if (i & 0x8000)\n" " printf(\"not expected\");\n" "The 'not expected' will be printed on the screen."); } //--------------------------------------------------------------------------- // Incomplete statement.. //--------------------------------------------------------------------------- void CheckOther::checkIncompleteStatement() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->str() == "(") { tok = tok->link(); if (Token::simpleMatch(tok, ") {") && Token::simpleMatch(tok->next()->link(), "} ;")) tok = tok->next()->link(); } else if (Token::simpleMatch(tok, "= {")) tok = tok->next()->link(); else if (tok->str() == "{" && Token::Match(tok->tokAt(-2), "%type% %var%")) tok = tok->link(); else if (Token::Match(tok, "[;{}] %str%") || Token::Match(tok, "[;{}] %num%")) { // No warning if numeric constant is followed by a "." or "," if (Token::Match(tok->next(), "%num% [,.]")) continue; // bailout if there is a "? :" in this statement bool bailout = false; for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { if (tok2->str() == "?") bailout = true; else if (tok2->str() == ";") break; } if (bailout) continue; constStatementError(tok->next(), tok->next()->isNumber() ? "numeric" : "string"); } } } void CheckOther::constStatementError(const Token *tok, const std::string &type) { reportError(tok, Severity::warning, "constStatement", "Redundant code: Found a statement that begins with " + type + " constant"); } //--------------------------------------------------------------------------- // str plus char //--------------------------------------------------------------------------- void CheckOther::strPlusChar() { // Don't use this check for Java and C# programs.. if (_tokenizer->isJavaOrCSharp()) { return; } bool charVars[10000] = {0}; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Declaring char variable.. if (Token::Match(tok, "char|int|short %var% [;=]")) { unsigned int varid = tok->next()->varId(); if (varid > 0 && varid < 10000) charVars[varid] = true; } // else if (Token::Match(tok, "[=(] %str% + %any%")) { // char constant.. const std::string s = tok->strAt(3); if (s[0] == '\'') strPlusCharError(tok->next()); // char variable.. unsigned int varid = tok->tokAt(3)->varId(); if (varid > 0 && varid < 10000 && charVars[varid]) strPlusCharError(tok->next()); } } } void CheckOther::strPlusCharError(const Token *tok) { reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkZeroDivision() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "[/%] %num%") && MathLib::isInt(tok->next()->str()) && MathLib::toLongNumber(tok->next()->str()) == 0L) { zerodivError(tok); } else if (Token::Match(tok, "div|ldiv|lldiv|imaxdiv ( %num% , %num% )") && MathLib::isInt(tok->strAt(4)) && MathLib::toLongNumber(tok->strAt(4)) == 0L) { zerodivError(tok); } } } void CheckOther::zerodivError(const Token *tok) { reportError(tok, Severity::error, "zerodiv", "Division by zero"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkMathFunctions() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->varId() == 0 && Token::Match(tok, "log|log10 ( %num% )")) { bool isNegative = MathLib::isNegative(tok->strAt(2)); bool isInt = MathLib::isInt(tok->strAt(2)); bool isFloat = MathLib::isFloat(tok->strAt(2)); if (isNegative && isInt && MathLib::toLongNumber(tok->strAt(2)) <= 0) { mathfunctionCallError(tok); // case log(-2) } else if (isNegative && isFloat && MathLib::toDoubleNumber(tok->strAt(2)) <= 0.) { mathfunctionCallError(tok); // case log(-2.0) } else if (!isNegative && isFloat && MathLib::toDoubleNumber(tok->strAt(2)) <= 0.) { mathfunctionCallError(tok); // case log(0.0) } else if (!isNegative && isInt && MathLib::toLongNumber(tok->strAt(2)) <= 0) { mathfunctionCallError(tok); // case log(0) } } // acos( x ), asin( x ) where x is defined for intervall [-1,+1], but not beyound else if (tok->varId() == 0 && Token::Match(tok, "acos|asin ( %num% )") && std::fabs(MathLib::toDoubleNumber(tok->strAt(2))) > 1.0) { mathfunctionCallError(tok); } // sqrt( x ): if x is negative the result is undefined else if (tok->varId() == 0 && Token::Match(tok, "sqrt|sqrtf|sqrtl ( %num% )") && MathLib::isNegative(tok->strAt(2))) { mathfunctionCallError(tok); } // atan2 ( x , y): x and y can not be zero, because this is mathematically not defined else if (tok->varId() == 0 && Token::Match(tok, "atan2 ( %num% , %num% )") && MathLib::isNullValue(tok->strAt(2)) && MathLib::isNullValue(tok->strAt(4))) { mathfunctionCallError(tok, 2); } // fmod ( x , y) If y is zero, then either a range error will occur or the function will return zero (implementation-defined). else if (tok->varId() == 0 && Token::Match(tok, "fmod ( %num% , %num% )") && MathLib::isNullValue(tok->strAt(4))) { mathfunctionCallError(tok, 2); } // pow ( x , y) If x is zero, and y is negative --> division by zero else if (tok->varId() == 0 && Token::Match(tok, "pow ( %num% , %num% )") && MathLib::isNullValue(tok->strAt(2)) && MathLib::isNegative(tok->strAt(4))) { mathfunctionCallError(tok, 2); } } } void CheckOther::mathfunctionCallError(const Token *tok, const unsigned int numParam) { if (tok) { if (numParam == 1) reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->strAt(2) + " to " + tok->str() + "() leads to undefined result"); else if (numParam == 2) reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->strAt(2) + " and " + tok->strAt(4) + " to " + tok->str() + "() leads to undefined result"); } else reportError(tok, Severity::error, "wrongmathcall", "Passing value " " to " "() leads to undefined result"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkCCTypeFunctions() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->varId() == 0 && Token::Match(tok, "isalnum|isalpha|iscntrl|isdigit|isgraph|islower|isprint|ispunct|isspace|isupper|isxdigit ( %num% )") && MathLib::isNegative(tok->strAt(2))) { cctypefunctionCallError(tok, tok->str(), tok->tokAt(2)->str()); } } } void CheckOther::cctypefunctionCallError(const Token *tok, const std::string &functionName, const std::string &value) { reportError(tok, Severity::error, "wrongcctypecall", "Passing value " + value + " to " + functionName + "() cause undefined behavior, which may lead to a crash"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- /** Is there a function with given name? */ static bool isFunction(const std::string &name, const Token *startToken) { const std::string pattern1(name + " ("); for (const Token *tok = startToken; tok; tok = tok->next()) { // skip executable scopes etc if (tok->str() == "(") { tok = tok->link(); if (Token::simpleMatch(tok, ") {")) tok = tok->next()->link(); else if (Token::simpleMatch(tok, ") const {")) tok = tok->linkAt(2); } // function declaration/implementation found if ((tok->str() == "*" || (tok->isName() && tok->str().find(":") ==std::string::npos)) && Token::simpleMatch(tok->next(), pattern1.c_str())) return true; } return false; } void CheckOther::checkMisusedScopedObject() { // Skip this check for .c files if (_tokenizer->code_is_c()) { return; } const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { // only check functions if (scope->type != Scope::eFunction) continue; unsigned int depth = 0; for (const Token *tok = scope->classStart; tok; tok = tok->next()) { if (tok->str() == "{") { ++depth; } else if (tok->str() == "}") { if (depth <= 1) break; --depth; } if (Token::Match(tok, "[;{}] %var% (") && Token::simpleMatch(tok->linkAt(2), ") ;") && symbolDatabase->isClassOrStruct(tok->next()->str()) && !isFunction(tok->next()->str(), _tokenizer->tokens())) { tok = tok->next(); misusedScopeObjectError(tok, tok->str()); tok = tok->next(); } } } } void CheckOther::misusedScopeObjectError(const Token *tok, const std::string& varname) { reportError(tok, Severity::error, "unusedScopedObject", "instance of \"" + varname + "\" object destroyed immediately"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkIncorrectStringCompare() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, ". substr ( %any% , %num% ) ==|!= %str%")) { std::size_t clen = MathLib::toLongNumber(tok->strAt(5)); std::size_t slen = Token::getStrLength(tok->tokAt(8)); if (clen != slen) { incorrectStringCompareError(tok->next(), "substr", tok->strAt(8), tok->strAt(5)); } } if (Token::Match(tok, "%str% ==|!= %var% . substr ( %any% , %num% )")) { std::size_t clen = MathLib::toLongNumber(tok->strAt(8)); std::size_t slen = Token::getStrLength(tok); if (clen != slen) { incorrectStringCompareError(tok->next(), "substr", tok->str(), tok->strAt(8)); } } if (Token::Match(tok, "&&|%oror% %str% &&|%oror%|)")) { // assert(condition && "debug message") would be considered a fp. if (tok->str() == "&&" && tok->strAt(2) == ")" && tok->linkAt(2)->previous()->str() == "assert") continue; incorrectStringBooleanError(tok->next(), tok->strAt(1)); } if (Token::Match(tok, "if|while|assert ( %str% &&|%oror%|)")) { // assert("debug message" && condition) would be considered a fp. if (tok->strAt(3) == "&&" && tok->str() == "assert") continue; incorrectStringBooleanError(tok->tokAt(2), tok->strAt(2)); } } } void CheckOther::incorrectStringCompareError(const Token *tok, const std::string& func, const std::string &string, const std::string &len) { reportError(tok, Severity::warning, "incorrectStringCompare", "String literal " + string + " doesn't match length argument for " + func + "(" + len + ")."); } void CheckOther::incorrectStringBooleanError(const Token *tok, const std::string& string) { reportError(tok, Severity::warning, "incorrectStringBooleanError", "A boolean comparison with the string literal " + string + " is always true."); } //----------------------------------------------------------------------------- // check for duplicate expressions in if statements // if (a) { } else if (a) { } //----------------------------------------------------------------------------- static const std::string stringifyTokens(const Token *start, const Token *end) { const Token *tok = start; std::string stringified; if (tok->isUnsigned()) stringified.append("unsigned "); else if (tok->isSigned()) stringified.append("signed "); if (tok->isLong()) stringified.append("long "); stringified.append(tok->str()); while (tok && tok->next() && tok != end) { if (tok->isUnsigned()) stringified.append("unsigned "); else if (tok->isSigned()) stringified.append("signed "); if (tok->isLong()) stringified.append("long "); tok = tok->next(); stringified.append(" "); stringified.append(tok->str()); } return stringified; } static bool expressionHasSideEffects(const Token *first, const Token *last) { for (const Token *tok = first; tok != last->next(); tok = tok->next()) { // check for assignment if (tok->isAssignmentOp()) return true; // check for inc/dec else if (Token::Match(tok, "++|--")) return true; // check for function call else if (Token::Match(tok, "%var% (") && !(Token::Match(tok, "c_str|string") || tok->isStandardType())) return true; } return false; } void CheckOther::checkDuplicateIf() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { // only check functions if (scope->type != Scope::eFunction) continue; // check all the code in the function for if (...) and else if (...) statements for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next()) { if (Token::simpleMatch(tok, "if (") && tok->strAt(-1) != "else" && Token::simpleMatch(tok->next()->link(), ") {")) { std::map expressionMap; // get the expression from the token stream std::string expression = stringifyTokens(tok->tokAt(2), tok->next()->link()->previous()); // save the expression and its location expressionMap.insert(std::make_pair(expression, tok)); // find the next else if (...) statement const Token *tok1 = tok->next()->link()->next()->link(); // check all the else if (...) statements while (Token::simpleMatch(tok1, "} else if (") && Token::simpleMatch(tok1->linkAt(3), ") {")) { // get the expression from the token stream expression = stringifyTokens(tok1->tokAt(4), tok1->linkAt(3)->previous()); // try to look up the expression to check for duplicates std::map::iterator it = expressionMap.find(expression); // found a duplicate if (it != expressionMap.end()) { // check for expressions that have side effects and ignore them if (!expressionHasSideEffects(tok1->tokAt(4), tok1->linkAt(3)->previous())) duplicateIfError(it->second, tok1->next()); } // not a duplicate expression so save it and its location else expressionMap.insert(std::make_pair(expression, tok1->next())); // find the next else if (...) statement tok1 = tok1->linkAt(3)->next()->link(); } tok = tok->next()->link()->next(); } } } } void CheckOther::duplicateIfError(const Token *tok1, const Token *tok2) { std::list toks; toks.push_back(tok2); toks.push_back(tok1); reportError(toks, Severity::style, "duplicateIf", "Found duplicate if expressions.\n" "Finding the same expression more than once is suspicious and might indicate " "a cut and paste or logic error. Please examine this code carefully to determine " "if it is correct."); } //----------------------------------------------------------------------------- // check for duplicate code in if and else branches // if (a) { b = true; } else { b = true; } //----------------------------------------------------------------------------- void CheckOther::checkDuplicateBranch() { if (!_settings->isEnabled("style")) return; if (!_settings->inconclusive) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { // only check functions if (scope->type != Scope::eFunction) continue; // check all the code in the function for if (..) else for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next()) { if (Token::simpleMatch(tok, "if (") && tok->strAt(-1) != "else" && Token::simpleMatch(tok->next()->link(), ") {") && Token::simpleMatch(tok->next()->link()->next()->link(), "} else {")) { // save if branch code std::string branch1 = stringifyTokens(tok->next()->link()->tokAt(2), tok->next()->link()->next()->link()->previous()); // find else branch const Token *tok1 = tok->next()->link()->next()->link(); // save else branch code std::string branch2 = stringifyTokens(tok1->tokAt(3), tok1->linkAt(2)->previous()); // check for duplicates if (branch1 == branch2) duplicateBranchError(tok, tok1->tokAt(2)); tok = tok->next()->link()->next(); } } } } void CheckOther::duplicateBranchError(const Token *tok1, const Token *tok2) { std::list toks; toks.push_back(tok2); toks.push_back(tok1); reportInconclusiveError(toks, Severity::style, "duplicateBranch", "Found duplicate branches for if and else.\n" "Finding the same code for an if branch and an else branch is suspicious and " "might indicate a cut and paste or logic error. Please examine this code " "carefully to determine if it is correct."); } namespace { struct ExpressionTokens { const Token *start; const Token *end; int count; ExpressionTokens(const Token *s, const Token *e): start(s), end(e), count(1) {} }; class Expressions { public: Expressions(): _start(0) {} void endExpr(const Token *end) { const std::string &e = _expression.str(); if (!e.empty()) { std::map::iterator it = _expressions.find(e); if (it == _expressions.end()) _expressions.insert(std::make_pair(e, ExpressionTokens(_start, end))); else it->second.count += 1; } _expression.str(""); _start = 0; } void append(const Token *tok) { if (!_start) _start = tok; _expression << tok->str(); } std::map &getMap() { return _expressions; } private: std::map _expressions; std::ostringstream _expression; const Token *_start; }; struct FuncFilter { FuncFilter(const Scope *scope, const Token *tok): _scope(scope), _tok(tok) {} bool operator()(const Function &func) { // todo: function args, etc?? bool matchingFunc = func.type == Function::eFunction && _tok->str() == func.token->str(); // either a class function, or a global function with the same name return (_scope && _scope == func.functionScope && matchingFunc) || (!_scope && matchingFunc); } const Scope *_scope; const Token *_tok; }; bool inconclusiveFunctionCall(const SymbolDatabase *symbolDatabase, const std::list &constFunctions, const ExpressionTokens &tokens) { const Token *start = tokens.start; const Token *end = tokens.end; // look for function calls between start and end... for (const Token *tok = start; tok && tok != end; tok = tok->next()) { if (tok != start && tok->str() == "(") { // go back to find the function call. const Token *prev = tok->previous(); if (prev->str() == ">") { // ignore template functions like boo() return true; } if (prev && prev->isName()) { const Variable *v = 0; if (Token::Match(prev->tokAt(-2), "%var% .")) { const Token *scope = prev->tokAt(-2); v = symbolDatabase->getVariableFromVarId(scope->varId()); } // hard coded list of safe, no-side-effect functions if (v == 0 && Token::Match(prev, "strcmp|strncmp|strlen|memcmp|strcasecmp|strncasecmp")) return false; std::list::const_iterator it = std::find_if(constFunctions.begin(), constFunctions.end(), FuncFilter(v ? v->type(): 0, prev)); if (it == constFunctions.end()) return true; } } } return false; } bool notconst(const Function &func) { return !func.isConst; } void getConstFunctions(const SymbolDatabase *symbolDatabase, std::list &constFunctions) { std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { std::list::const_iterator func; // only add const functions that do not have a non-const overloaded version // since it is pretty much impossible to tell which is being called. typedef std::map > StringFunctionMap; StringFunctionMap functionsByName; for (func = scope->functionList.begin(); func != scope->functionList.end(); ++func) { StringFunctionMap::iterator it = functionsByName.find(func->token->str()); Scope *currScope = const_cast(&*scope); if (it == functionsByName.end()) { std::list tmp; tmp.push_back(*func); tmp.back().functionScope = currScope; functionsByName[func->token->str()] = tmp; } else { it->second.push_back(*func); it->second.back().functionScope = currScope; } } for (StringFunctionMap::iterator it = functionsByName.begin(); it != functionsByName.end(); ++it) { std::list::const_iterator nc = std::find_if(it->second.begin(), it->second.end(), notconst); if (nc == it->second.end()) { // ok to add all of them constFunctions.splice(constFunctions.end(), it->second); } } } } } void CheckOther::checkExpressionRange(const std::list &constFunctions, const Token *start, const Token *end, const std::string &toCheck) { if (!start || !end) return; Expressions expressions; std::string opName; int level = 0; for (const Token *tok = start->next(); tok && tok != end; tok = tok->next()) { if (tok->str() == ")") level--; else if (tok->str() == "(") level++; if (level == 0 && Token::Match(tok, toCheck.c_str())) { opName = tok->str(); expressions.endExpr(tok); } else { expressions.append(tok); } } expressions.endExpr(end); std::map::const_iterator it = expressions.getMap().begin(); const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (; it != expressions.getMap().end(); ++it) { if (it->second.count > 1 && (it->first.find("(") == std::string::npos || !inconclusiveFunctionCall(symbolDatabase, constFunctions, it->second))) { duplicateExpressionError(it->second.start, it->second.start, opName); } } } void CheckOther::complexDuplicateExpressionCheck(const std::list &constFunctions, const Token *classStart, const std::string &toCheck, const std::string &alt) { std::string statementStart(",|=|return"); if (!alt.empty()) statementStart += "|" + alt; std::string statementEnd(";|,"); if (!alt.empty()) statementEnd += "|" + alt; for (const Token *tok = classStart; tok && tok != classStart->link(); tok = tok->next()) { if (!Token::Match(tok, toCheck.c_str())) continue; // look backward for the start of the statement const Token *start = 0; int level = 0; for (const Token *tok1 = tok->previous(); tok1 && tok1 != classStart; tok1 = tok1->previous()) { if (tok1->str() == ")") level++; else if (tok1->str() == "(") level--; if (level < 0 || (level == 0 && Token::Match(tok1, statementStart.c_str()))) { start = tok1; break; } } const Token *end = 0; level = 0; // look for the end of the statement for (const Token *tok1 = tok->next(); tok1 && tok1 != classStart->link(); tok1 = tok1->next()) { if (tok1->str() == ")") level--; else if (tok1->str() == "(") level++; if (level < 0 || (level == 0 && Token::Match(tok1, statementEnd.c_str()))) { end = tok1; break; } } checkExpressionRange(constFunctions, start, end, toCheck); } } //--------------------------------------------------------------------------- // check for the same expression on both sides of an operator // (x == x), (x && x), (x || x) // (x.y == x.y), (x.y && x.y), (x.y || x.y) //--------------------------------------------------------------------------- void CheckOther::checkDuplicateExpression() { if (!_settings->isEnabled("style")) return; // Parse all executing scopes.. const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; std::list constFunctions; getConstFunctions(symbolDatabase, constFunctions); for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { // only check functions if (scope->type != Scope::eFunction) continue; complexDuplicateExpressionCheck(constFunctions, scope->classStart, "%or%", ""); complexDuplicateExpressionCheck(constFunctions, scope->classStart, "%oror%", ""); complexDuplicateExpressionCheck(constFunctions, scope->classStart, "&", "%oror%|%or%"); complexDuplicateExpressionCheck(constFunctions, scope->classStart, "&&", "%oror%|%or%"); for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next()) { if (Token::Match(tok, ",|=|return|(|&&|%oror% %var% ==|!=|<=|>=|<|>|- %var% )|&&|%oror%|;|,") && tok->strAt(1) == tok->strAt(3)) { // float == float and float != float are valid NaN checks if (Token::Match(tok->tokAt(2), "==|!=") && tok->next()->varId()) { const Variable * var = symbolDatabase->getVariableFromVarId(tok->next()->varId()); if (var && var->typeStartToken() == var->typeEndToken()) { if (Token::Match(var->typeStartToken(), "float|double")) continue; } } duplicateExpressionError(tok->next(), tok->tokAt(3), tok->strAt(2)); } else if (Token::Match(tok, ",|=|return|(|&&|%oror% %var% . %var% ==|!=|<=|>=|<|>|- %var% . %var% )|&&|%oror%|;|,") && tok->strAt(1) == tok->strAt(5) && tok->strAt(3) == tok->strAt(7)) { duplicateExpressionError(tok->next(), tok->tokAt(6), tok->strAt(4)); } } } } void CheckOther::duplicateExpressionError(const Token *tok1, const Token *tok2, const std::string &op) { std::list toks; toks.push_back(tok2); toks.push_back(tok1); reportError(toks, Severity::style, "duplicateExpression", "Same expression on both sides of \'" + op + "\'.\n" "Finding the same expression on both sides of an operator is suspicious and might " "indicate a cut and paste or logic error. Please examine this code carefully to " "determine if it is correct."); } //--------------------------------------------------------------------------- // Check for string comparison involving two static strings. // if(strcmp("00FF00","00FF00")==0) // <- statement is always true //--------------------------------------------------------------------------- void CheckOther::checkAlwaysTrueOrFalseStringCompare() { if (!_settings->isEnabled("style") && !_settings->isEnabled("performance")) return; const char pattern1[] = "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp ( %str% , %str% "; const char pattern2[] = "QString :: compare ( %str% , %str% )"; const char pattern3[] = "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp ( %var% , %var% "; const Token *tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, pattern1)) != NULL) { alwaysTrueFalseStringCompareError(tok, tok->strAt(2), tok->strAt(4)); tok = tok->tokAt(5); } tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, pattern2)) != NULL) { alwaysTrueFalseStringCompareError(tok, tok->strAt(4), tok->strAt(6)); tok = tok->tokAt(7); } tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, pattern3)) != NULL) { const Token *var1 = tok->tokAt(2); const Token *var2 = tok->tokAt(4); const std::string &str1 = var1->str(); const std::string &str2 = var2->str(); if (str1 == str2) alwaysTrueStringVariableCompareError(tok, str1, str2); tok = tok->tokAt(5); } } void CheckOther::alwaysTrueFalseStringCompareError(const Token *tok, const std::string& str1, const std::string& str2) { const std::size_t stringLen = 10; const std::string string1 = (str1.size() < stringLen) ? str1 : (str1.substr(0, stringLen-2) + ".."); const std::string string2 = (str2.size() < stringLen) ? str2 : (str2.substr(0, stringLen-2) + ".."); if (str1 == str2) { reportError(tok, Severity::warning, "staticStringCompare", "Comparison of always identical static strings.\n" "The compared strings, '" + string1 + "' and '" + string2 + "', are always identical. " "If the purpose is to compare these two strings, the comparison is unnecessary. " "If the strings are supposed to be different, then there is a bug somewhere."); } else if (_settings->isEnabled("performance")) { reportError(tok, Severity::performance, "staticStringCompare", "Unnecessary comparison of static strings.\n" "The compared strings, '" + string1 + "' and '" + string2 + "', are static and always different. " "If the purpose is to compare these two strings, the comparison is unnecessary."); } } void CheckOther::alwaysTrueStringVariableCompareError(const Token *tok, const std::string& str1, const std::string& str2) { reportError(tok, Severity::warning, "stringCompare", "Comparison of identical string variables.\n" "The compared strings, '" + str1 + "' and '" + str2 + "', are identical. " "This could be a logic bug."); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::sizeofsizeof() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "sizeof (| sizeof")) { sizeofsizeofError(tok); tok = tok->next(); } } } void CheckOther::sizeofsizeofError(const Token *tok) { reportError(tok, Severity::warning, "sizeofsizeof", "Calling sizeof for 'sizeof'.\n" "Calling sizeof for 'sizeof looks like a suspicious code and " "most likely there should be just one 'sizeof'. The current " "code is equivalent to 'sizeof(size_t)'"); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::sizeofCalculation() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "sizeof (")) { unsigned int parlevel = 0; for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { if (tok2->str() == "(") ++parlevel; else if (tok2->str() == ")") { if (parlevel <= 1) break; --parlevel; } else if (Token::Match(tok2, "+|/")) { sizeofCalculationError(tok2); break; } } } } } void CheckOther::sizeofCalculationError(const Token *tok) { reportError(tok, Severity::warning, "sizeofCalculation", "Found calculation inside sizeof()"); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::checkAssignBoolToPointer() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "[;{}] %var% = %bool% ;")) { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const Variable *var1(symbolDatabase->getVariableFromVarId(tok->next()->varId())); // Is variable a pointer? if (var1 && var1->nameToken()->strAt(-1) == "*") assignBoolToPointerError(tok->next()); } } } void CheckOther::assignBoolToPointerError(const Token *tok) { reportError(tok, Severity::error, "assignBoolToPointer", "Assigning bool value to pointer (converting bool value to address)"); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::checkComparisonOfBoolExpressionWithInt() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "&&|%oror% %any% ) ==|!=|>|< %num%")) { const std::string& op = tok->strAt(3); const std::string& num = tok->strAt(4); if ((op == "<" || num != "0") && (op == ">" || num != "1")) { comparisonOfBoolExpressionWithIntError(tok->next()); } } else if (Token::Match(tok, "%num% ==|!=|>|< ( %any% &&|%oror%")) { const std::string& op = tok->strAt(1); const std::string& num = tok->str(); if ((op == ">" || num != "0") && (op == "<" || num != "1")) { comparisonOfBoolExpressionWithIntError(tok->next()); } } } } void CheckOther::comparisonOfBoolExpressionWithIntError(const Token *tok) { reportError(tok, Severity::warning, "compareBoolExpressionWithInt", "Comparison of a boolean expression with an integer other than 0 or 1."); } //--------------------------------------------------------------------------- // Check testing sign of unsigned variables. //--------------------------------------------------------------------------- void CheckOther::checkSignOfUnsignedVariable() { if (!_settings->isEnabled("style")) return; const bool inconclusive = _tokenizer->codeWithTemplates(); if (inconclusive && !_settings->inconclusive) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { // only check functions if (scope->type != Scope::eFunction) continue; // check all the code in the function for (const Token *tok = scope->classStart; tok && tok != scope->classStart->link(); tok = tok->next()) { if (Token::Match(tok, ";|(|&&|%oror% %var% <|<= 0 ;|)|&&|%oror%") && tok->next()->varId()) { const Variable * var = symbolDatabase->getVariableFromVarId(tok->next()->varId()); if (var && var->typeEndToken()->isUnsigned()) unsignedLessThanZeroError(tok->next(), tok->next()->str(), inconclusive); } else if (Token::Match(tok, ";|(|&&|%oror% 0 > %var% ;|)|&&|%oror%") && tok->tokAt(3)->varId()) { const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId()); if (var && var->typeEndToken()->isUnsigned()) unsignedLessThanZeroError(tok->tokAt(3), tok->strAt(3), inconclusive); } else if (Token::Match(tok, ";|(|&&|%oror% 0 <= %var% ;|)|&&|%oror%") && tok->tokAt(3)->varId()) { const Variable * var = symbolDatabase->getVariableFromVarId(tok->tokAt(3)->varId()); if (var && var->typeEndToken()->isUnsigned()) unsignedPositiveError(tok->tokAt(3), tok->strAt(3), inconclusive); } else if (Token::Match(tok, ";|(|&&|%oror% %var% >= 0 ;|)|&&|%oror%") && tok->next()->varId()) { const Variable * var = symbolDatabase->getVariableFromVarId(tok->next()->varId()); if (var && var->typeEndToken()->isUnsigned()) unsignedPositiveError(tok->next(), tok->next()->str(), inconclusive); } } } } void CheckOther::unsignedLessThanZeroError(const Token *tok, const std::string &varname, bool inconclusive) { if (inconclusive) { reportInconclusiveError(tok, Severity::style, "unsignedLessThanZero", "Checking if unsigned variable '" + varname + "' is less than zero. This might be a false warning.\n" "Checking if unsigned variable '" + varname + "' is less than zero. An unsigned " "variable will never be negative so it is either pointless or an error to check if it is. " "It's not known if the used constant is a template parameter or not and therefore " "this message might be a false warning"); } else { reportError(tok, Severity::style, "unsignedLessThanZero", "Checking if unsigned variable '" + varname + "' is less than zero.\n" "An unsigned variable will never be negative so it is either pointless or " "an error to check if it is."); } } void CheckOther::unsignedPositiveError(const Token *tok, const std::string &varname, bool inconclusive) { if (inconclusive) { reportInconclusiveError(tok, Severity::style, "unsignedPositive", "Checking if unsigned variable '" + varname + "' is positive is always true. This might be a false warning.\n" "Checking if unsigned variable '" + varname + "' is positive is always true. " "An unsigned variable will always be positive so it is either pointless or " "an error to check if it is. It's not known if the used constant is a " "template parameter or not and therefore this message might be a false warning"); } else { reportError(tok, Severity::style, "unsignedPositive", "Checking if unsigned variable '" + varname + "' is positive is always true.\n" "An unsigned variable will always be positive so it is either pointless or " "an error to check if it is."); } }