/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2010 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 "tokenize.h" #include "executionpath.h" #include #include #include #include #include #include #include #include // fabs() //--------------------------------------------------------------------------- // Register this check class (by creating a static instance of it) namespace { CheckOther instance; } //--------------------------------------------------------------------------- void CheckOther::warningOldStylePointerCast() { if (!_settings->_checkCodingStyle) 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; int addToIndex = 0; if (tok->tokAt(1)->str() == "const") addToIndex = 1; if (tok->tokAt(4 + addToIndex)->str() == "const") continue; // Is "type" a class? const std::string pattern("class " + tok->tokAt(1 + addToIndex)->str()); if (!Token::findmatch(_tokenizer->tokens(), pattern.c_str())) continue; cstyleCastError(tok); } } //--------------------------------------------------------------------------- // Redundant code.. //--------------------------------------------------------------------------- void CheckOther::warningRedundantCode() { if (!_settings->_checkCodingStyle) return; // if (p) delete p for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (! Token::simpleMatch(tok, "if (")) continue; const Token *tok2 = tok->tokAt(2); /* * Possible if-constructions: * * if (var) * if (this->var) * if (Foo::var) * **/ std::string varname = concatNames(&tok2); if (!Token::Match(tok2, "%var% ) {")) continue; tok2 = tok2->tokAt(3); /* * Possible constructions: * * - delete %var% * - delete [] %var% * - free ( %var ) * - kfree ( %var% ) * * Where %var% may be: * - just variable name (var) * - class member (this->var) * - static member (Class::var) * **/ bool funcHasBracket = false; if (Token::Match(tok2, "free|kfree (")) { tok2 = tok2->tokAt(2); funcHasBracket = true; } else if (tok2->str() == "delete") { tok2 = tok2->next(); if (Token::simpleMatch(tok2, "[ ]")) { tok2 = tok2->tokAt(2); } } std::string varname2 = concatNames(&tok2); if (Token::Match(tok2, "%var%") && varname == varname2) tok2 = tok2->next(); else continue; if (funcHasBracket) { if (tok2->str() != ")") { continue; } else { tok2 = tok2->next(); } } /* * Possible constructions: * * - if (%var%) { delete %var%; } * - if (%var%) { delete %var%; %var% = 0; } * **/ if (Token::Match(tok2, "; } !!else")) { redundantIfDelete0Error(tok); } else if (Token::Match(tok2, "; %var%")) { tok2 = tok2->next(); std::string varname3 = concatNames(&tok2); if (Token::Match(tok2, "%var% = 0 ; } !!else") && varname2 == varname3) { redundantIfDelete0Error(tok); } } } // Redundant condition // if (haystack.find(needle) != haystack.end()) // haystack.remove(needle); redundantCondition2(); } //--------------------------------------------------------------------------- void CheckOther::redundantCondition2() { const char pattern[] = "if ( %var% . find ( %any% ) != %var% . end ( ) ) " "{|{|" " %var% . remove ( %any% ) ; " "}|}|"; const Token *tok = Token::findmatch(_tokenizer->tokens(), pattern); while (tok) { bool b(tok->tokAt(15)->str() == "{"); // Get tokens for the fields %var% and %any% const Token *var1 = tok->tokAt(2); const Token *any1 = tok->tokAt(6); const Token *var2 = tok->tokAt(9); const Token *var3 = tok->tokAt(b ? 16 : 15); const Token *any2 = tok->tokAt(b ? 20 : 19); // Check if all the "%var%" fields are the same and if all the "%any%" are the same.. if (var1->str() == var2->str() && var2->str() == var3->str() && any1->str() == any2->str()) { redundantIfRemoveError(tok); } tok = Token::findmatch(tok->next(), pattern); } } //--------------------------------------------------------------------------- // "if (strlen(s))" can be rewritten as "if (*s != '\0')" //--------------------------------------------------------------------------- void CheckOther::checkEmptyStringTest() { if (!_settings->_checkCodingStyle) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Non-empty string tests if (Token::Match(tok, "if ( strlen ( %any% ) )")) { emptyStringTestError(tok, tok->strAt(4), false); } else if (Token::Match(tok, "strlen ( %any% ) !=|> 0")) { emptyStringTestError(tok, tok->strAt(2), false); } else if (Token::Match(tok, "0 < strlen ( %any% )")) { emptyStringTestError(tok, tok->strAt(4), false); } // Empty string tests else if (Token::Match(tok, "! strlen ( %any% )")) { emptyStringTestError(tok, tok->strAt(3), true); } else if (Token::Match(tok, "strlen ( %any% ) == 0")) { emptyStringTestError(tok, tok->strAt(2), true); } } } //--------------------------------------------------------------------------- // 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 ((tok->str() != "strtol") && (tok->str() != "strtoul")) continue; // Locate the third parameter of the function call.. int parlevel = 0; int param = 1; for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == "(") ++parlevel; else if (tok2->str() == ")") --parlevel; else if (parlevel == 1 && tok2->str() == ",") { ++param; if (param == 3) { if (Token::Match(tok2, ", %num% )")) { int 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 && tok2->str() != ",") tok2 = tok2->next(); // is any source buffer overlapping the target buffer? int parlevel = 0; while ((tok2 = tok2->next()) != NULL) { if (tok2->str() == "(") ++parlevel; else if (tok2->str() == ")") { --parlevel; if (parlevel < 0) break; } else if (parlevel == 0 && Token::Match(tok2, ", %varid% [,)]", varid)) { sprintfOverlappingDataError(tok2->next(), tok2->next()->str()); break; } } } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Check for unsigned divisions //--------------------------------------------------------------------------- void CheckOther::checkUnsignedDivision() { if (!_settings->inconclusive || !_settings->_checkCodingStyle) 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->tokAt(1)->isUnsigned()) varsign[tok->tokAt(2)->varId()] = 'u'; else varsign[tok->tokAt(2)->varId()] = 's'; } else if (!Token::Match(tok, "[).]") && Token::Match(tok->next(), "%var% / %var%") && tok->tokAt(1)->varId() != 0 && tok->tokAt(3)->varId() != 0) { char sign1 = varsign[tok->tokAt(1)->varId()]; char sign2 = varsign[tok->tokAt(3)->varId()]; if (sign1 && sign2 && sign1 != sign2) { // One of the operands are signed, the other is unsigned.. udivWarning(tok->next()); } } else if (!Token::Match(tok, "[).]") && Token::Match(tok->next(), "%var% / %num%")) { if (tok->strAt(3)[0] == '-' && ErrorLogger::udivError()) { char sign1 = varsign[tok->tokAt(1)->varId()]; if (sign1 == 'u') { udivError(tok->next()); } } } else if (Token::Match(tok, "[([=*/+-,] %num% / %var%")) { if (tok->strAt(1)[0] == '-' && ErrorLogger::udivError()) { char sign2 = varsign[tok->tokAt(3)->varId()]; if (sign2 == 'u') { udivError(tok->next()); } } } } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Unreachable code below a 'return' //--------------------------------------------------------------------------- void CheckOther::unreachableCode() { if (!_settings->_checkCodingStyle) return; const Token *tok = _tokenizer->tokens(); while ((tok = Token::findmatch(tok, "[;{}] return")) != NULL) { // Goto the 'return' token tok = tok->next(); // Locate the end of the 'return' statement while (tok && tok->str() != ";") tok = tok->next(); while (tok && tok->next() && tok->next()->str() == ";") tok = tok->next(); if (!tok) break; // If there is a statement below the return it is unreachable /* original: if (!Token::Match(tok, "; case|default|}|#") && !Token::Match(tok, "; %var% :") && !Token::simpleMatch(tok, "; break")) */ if (Token::simpleMatch(tok, "; break")) { unreachableCodeError(tok->next()); } } } void CheckOther::unreachableCodeError(const Token *tok) { reportError(tok, Severity::style, "unreachableCode", "Unreachable code below a 'return'"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Usage of function variables //--------------------------------------------------------------------------- static bool isOp(const Token *tok) { return bool(tok && (tok->str() == "&&" || tok->str() == "||" || tok->str() == "==" || tok->str() == "!=" || tok->str() == "<" || tok->str() == "<=" || tok->str() == ">" || tok->str() == ">=" || tok->str() == "<<" || Token::Match(tok, "[+-*/%&!~|^,[])?:]"))); } class VariableScope { public: /** Store information about variable usage in this scope */ class VariableUsage { public: VariableUsage(const Token *name = 0, const Token *type = 0, bool read = false, bool write = false, bool modified = false, bool aliased = false) : _name(name), _type(type), _read(read), _write(write), _modified(modified), _aliased(aliased) { } /** variable is used.. set both read+write */ void use() { _read = true; _write = true; } /** is variable unused? */ bool unused() const { return (_read == false && _write == false); } const Token *_name; const Token *_type; bool _read; bool _write; bool _modified; // read/modify/write bool _aliased; // pointer or reference }; typedef std::map VariableMap; private: VariableMap _varUsage; std::vector _varScope; VariableScope *_varScopeBack; public: VariableScope(VariableScope *back = 0) : _varScopeBack(back) { } ~VariableScope() { for (unsigned int i = 0; i < _varScope.size(); i++) delete _varScope[i]; } VariableScope *addScope() { _varScope.push_back(new VariableScope(this)); return _varScope.back(); } VariableScope *lastScope() { return _varScopeBack; } void clear() { _varUsage.clear(); } void addVar(const Token *name, const Token *type, bool write_ = false, bool aliased = false) { _varUsage.insert(std::make_pair(name->str(), VariableUsage(name, type, false, write_, false, aliased))); } const VariableMap &varUsage() const { return _varUsage; } void read(const Token *tok); void write(const Token *tok); void use(const Token *tok); void modified(const Token *tok); void checkUsage(CheckOther * check); }; void VariableScope::read(const Token *tok) { VariableScope * scope = this; while (scope) { VariableMap::iterator i = scope->_varUsage.find(tok->str()); if (i != scope->varUsage().end()) { i->second._read = true; return; } scope = scope->lastScope(); } } void VariableScope::write(const Token *tok) { VariableScope * scope = this; while (scope) { VariableMap::iterator i = scope->_varUsage.find(tok->str()); if (i != scope->varUsage().end()) { i->second._write = true; return; } scope = scope->lastScope(); } } void VariableScope::use(const Token *tok) { VariableScope * scope = this; while (scope) { VariableMap::iterator i = scope->_varUsage.find(tok->str()); if (i != scope->varUsage().end()) { i->second.use(); return; } scope = scope->lastScope(); } } void VariableScope::modified(const Token *tok) { VariableScope * scope = this; while (scope) { VariableMap::iterator i = scope->_varUsage.find(tok->str()); if (i != scope->varUsage().end()) { i->second._modified = true; return; } scope = scope->lastScope(); } } void VariableScope::checkUsage(CheckOther *checkOther) { VariableMap::const_iterator it; for (it = _varUsage.begin(); it != _varUsage.end(); ++it) { const std::string &varname = it->first; const VariableUsage &usage = it->second; if (usage.unused() && !usage._modified) checkOther->unusedVariableError(usage._name, varname); else if (usage._modified & !usage._write) checkOther->unassignedVariableError(usage._name, varname); else if (!usage._read && !usage._modified && !usage._aliased) checkOther->unreadVariableError(usage._name, varname); else if (!usage._write) checkOther->unassignedVariableError(usage._name, varname); } for (unsigned int i = 0 ; i < _varScope.size(); i++) _varScope[i]->checkUsage(checkOther); } void CheckOther::functionVariableUsage() { if (!_settings->_checkCodingStyle) return; // Parse all executing scopes.. for (const Token *token = Token::findmatch(_tokenizer->tokens(), ") const| {"); token;) { // goto "{" while (token->str() != "{") token = token->next(); // First token for the current scope.. const Token * const tok1 = token; // Find next scope that will be checked next time.. token = Token::findmatch(token->link(), ") const| {"); // Varname, usage {read, write, modified, ...} // there can be multiple variables with the same name but in different scopes VariableScope rootScope; VariableScope * varScope = &rootScope; unsigned int indentlevel = 1; for (const Token *tok = tok1; tok; tok = tok->next()) { if (tok->str() == "{" && tok != tok1) { ++indentlevel; varScope = varScope->addScope(); } else if (tok->str() == "}") { --indentlevel; if (indentlevel == 0) break; varScope = varScope->lastScope(); } else if (Token::Match(tok, "struct|union|class {") || Token::Match(tok, "struct|union|class %type% {")) { while (tok->str() != "{") tok = tok->next(); tok = tok->link(); if (! tok) break; } if (Token::Match(tok, "[;{}] asm ( ) ;")) { varScope->clear(); break; } // standard type declaration: int i; if (Token::Match(tok, "[;{}] %type% %var% ;|=") && tok->next()->isStandardType()) { varScope->addVar(tok->tokAt(2), tok->next(), tok->tokAt(3)->str() == "="); tok = tok->tokAt(2); } // standard type declaration and initialization using constructor: int i(0); else if (Token::Match(tok, "[;{}] %type% %var% ( %any% ) ;") && tok->next()->isStandardType()) { varScope->addVar(tok->tokAt(2), tok->next(), true); // check if a local variable is used to initialize this variable if (tok->tokAt(4)->varId() > 0) varScope->read(tok->tokAt(4)); tok = tok->tokAt(5); } // standard type decelaration of array of with optional initialization: int i[10]; int j[2] = { 0, 1 }; else if (Token::Match(tok, "[;{}] %type% %var% [ %num% ] ;|=") && tok->next()->isStandardType()) { varScope->addVar(tok->tokAt(2), tok->next(), tok->tokAt(6)->str() == "=", false); tok = tok->tokAt(5); } // pointer or reference declaration with optional initialization: int * i; int * j = 0; else if (Token::Match(tok, "[;{}] %type% *|& %var% ;|=")) { if (tok->next()->str() != "return") { varScope->addVar(tok->tokAt(3), tok->next(), tok->tokAt(4)->str() == "=", true); tok = tok->tokAt(3); } } // const pointer or reference declaration with optional initialization: const int * i; const int * j = 0; else if (Token::Match(tok, "[;{}] const %type% *|& %var% ;|=")) { varScope->addVar(tok->tokAt(4), tok->tokAt(2), tok->tokAt(5)->str() == "=", true); tok = tok->tokAt(4); } // pointer or reference of struct or union declaration with optional initialization: struct s * i; struct s * j = 0; else if (Token::Match(tok, "[;{}] struct|union %type% *|& %var% ;|=")) { varScope->addVar(tok->tokAt(4), tok->tokAt(2), tok->tokAt(5)->str() == "=", true); tok = tok->tokAt(4); } // const pointer or reference of struct or union declaration with optional initialization: const struct s * i; const struct s * j = 0; else if (Token::Match(tok, "[;{}] const struct|union %type% *|& %var% ;|=")) { varScope->addVar(tok->tokAt(5), tok->tokAt(3), tok->tokAt(6)->str() == "=", true); tok = tok->tokAt(5); } else if (Token::Match(tok, "[;{}] %type% &|* %var% ( %any% ) ;") && (tok->next()->isStandardType() || tok->next()->str() == "void")) { varScope->addVar(tok->tokAt(3), tok->next(), true, true); // check if a local variable is used to initialize this variable if (tok->tokAt(5)->varId() > 0) { if (tok->tokAt(2)->str() == "&") varScope->read(tok->tokAt(5)); else varScope->use(tok->tokAt(5)); } tok = tok->tokAt(6); } else if (Token::Match(tok, "[;{}] %type% *|& %var% [ %num% ] ;|=") && (tok->next()->isStandardType() || tok->next()->str() == "void")) { varScope->addVar(tok->tokAt(3), tok->next(), tok->tokAt(7)->str() == "=", true); tok = tok->tokAt(6); } else if (Token::Match(tok, "[;{}] const %type% *|& %var% [ %num% ] ;|=") && (tok->tokAt(2)->isStandardType() || tok->tokAt(2)->str() == "void")) { varScope->addVar(tok->tokAt(4), tok->next(), tok->tokAt(8)->str() == "=", true); tok = tok->tokAt(7); } else if (Token::Match(tok, "delete|return %var%")) varScope->read(tok->next()); else if (Token::Match(tok, "%var% =")) varScope->write(tok); else if (Token::Match(tok, "%var% [") && Token::Match(tok->next()->link(), "] =")) varScope->write(tok); else if (Token::Match(tok, "else %var% =")) varScope->write(tok->next()); else if (Token::Match(tok, ">>|& %var%")) varScope->use(tok->next()); // use = read + write else if (Token::Match(tok, "[(,] %var% [,)]")) varScope->use(tok->next()); // use = read + write else if (Token::Match(tok, " %var% .")) varScope->use(tok); // use = read + write else if ((Token::Match(tok, "[(=&!]") || isOp(tok)) && (Token::Match(tok->next(), "%var%") && !Token::Match(tok->next(), "true|false"))) varScope->read(tok->next()); else if (Token::Match(tok, "-=|+=|*=|/=|&=|^= %var%") || Token::Match(tok, "|= %var%")) varScope->modified(tok->next()); else if (Token::Match(tok, "%var%") && (tok->next()->str() == ")" || isOp(tok->next()))) varScope->read(tok); else if (Token::Match(tok, "; %var% ;")) varScope->read(tok->next()); else if (Token::Match(tok, "++|-- %var%")) varScope->modified(tok->next()); else if (Token::Match(tok, "%var% ++|--")) varScope->modified(tok); } // Check usage of all variables in the current scope.. rootScope.checkUsage(this); } } void CheckOther::unusedVariableError(const Token *tok, const std::string &varname) { reportError(tok, Severity::style, "unusedVariable", "Unused variable: " + varname); } void CheckOther::unreadVariableError(const Token *tok, const std::string &varname) { reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is assigned a value that is never used"); } void CheckOther::unassignedVariableError(const Token *tok, const std::string &varname) { reportError(tok, Severity::style, "unassignedVariable", "Variable '" + varname + "' is not assigned a value"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Check scope of variables.. //--------------------------------------------------------------------------- void CheckOther::checkVariableScope() { if (!_settings->_checkCodingStyle) return; // Walk through all tokens.. bool func = false; int indentlevel = 0; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Skip class and struct declarations.. if ((tok->str() == "class") || (tok->str() == "struct")) { 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() == "}") { --indentlevel; if (indentlevel == 0) func = false; } if (indentlevel == 0 && Token::simpleMatch(tok, ") {")) { func = true; } if (indentlevel > 0 && func && 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 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() == "{") { ++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; } if (Token::simpleMatch(tok, "do {")) 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); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Check for constant function parameters //--------------------------------------------------------------------------- void CheckOther::checkConstantFunctionParameter() { if (!_settings->_checkCodingStyle) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::Match(tok, "[,(] const std :: %type% %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. const std::string pattern(std::string("class|struct ") + tok->strAt(2)); if (Token::findmatch(_tokenizer->tokens(), pattern.c_str())) { passedByValueError(tok, tok->strAt(3)); } } } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Check that all struct members are used //--------------------------------------------------------------------------- void CheckOther::checkStructMemberUsage() { if (!_settings->_checkCodingStyle) return; std::string structname; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->fileIndex() != 0) continue; if (Token::Match(tok, "struct|union %type% {")) { structname.clear(); if (Token::simpleMatch(tok->previous(), "extern")) continue; if ((!tok->previous() || Token::simpleMatch(tok->previous(), ";")) && Token::Match(tok->tokAt(2)->link(), ("} ; " + tok->strAt(1) + " %var% ;").c_str())) continue; structname = tok->strAt(1); // Bail out if struct/union contain any functions for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { if (tok2->str() == "(") { structname = ""; break; } if (tok2->str() == "}") break; } // Bail out if some data is casted to struct.. const std::string s("( struct| " + tok->next()->str() + " * ) & %var% ["); if (Token::findmatch(tok, s.c_str())) structname = ""; // Try to prevent false positives when struct members are not used directly. if (Token::findmatch(tok, (structname + " *").c_str())) structname = ""; else if (Token::findmatch(tok, (structname + " %type% *").c_str())) structname = ""; } if (tok->str() == "}") structname = ""; if (!structname.empty() && Token::Match(tok, "[{;]")) { // Declaring struct variable.. std::string varname; if (Token::Match(tok->next(), "%type% %var% [;[]")) varname = tok->strAt(2); else if (Token::Match(tok->next(), "%type% %type% %var% [;[]")) varname = tok->strAt(3); else if (Token::Match(tok->next(), "%type% * %var% [;[]")) varname = tok->strAt(3); else if (Token::Match(tok->next(), "%type% %type% * %var% [;[]")) varname = tok->strAt(4); else continue; // Check if the struct variable is anywhere in the file const std::string usagePattern(". " + varname); bool used = false; for (const Token *tok2 = _tokenizer->tokens(); tok2; tok2 = tok2->next()) { if (Token::simpleMatch(tok2, usagePattern.c_str())) { used = true; break; } } if (! used) { unusedStructMemberError(tok->next(), structname, varname); } } } } //--------------------------------------------------------------------------- // Check usage of char variables.. //--------------------------------------------------------------------------- void CheckOther::checkCharVariable() { if (!_settings->_checkCodingStyle) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Declaring the variable.. if (Token::Match(tok, "[{};(,] char %var% [;=,)]")) { // Check for unsigned char if (tok->tokAt(1)->isUnsigned()) continue; // Set tok to point to the variable name tok = tok->tokAt(2); if (tok->str() == "char") tok = tok->next(); // Check usage of char variable.. int indentlevel = 0; for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == "{") ++indentlevel; else if (tok2->str() == "}") { --indentlevel; if (indentlevel <= 0) break; } else if (tok2->str() == "return") continue; std::string temp = "%var% [ " + tok->str() + " ]"; if ((tok2->str() != ".") && Token::Match(tok2->next(), temp.c_str())) { 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 (std::string(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? if (!Token::findmatch(_tokenizer->tokens(), "short|int|long %varid%", tok2->next()->varId())) continue; // This is an error.. charBitOpError(tok2); break; } } } } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // Incomplete statement.. //--------------------------------------------------------------------------- void CheckOther::checkIncompleteStatement() { if (!_settings->_checkCodingStyle) return; int parlevel = 0; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->str() == "(") ++parlevel; else if (tok->str() == ")") --parlevel; if (parlevel != 0) continue; if (Token::simpleMatch(tok, "= {")) { /* We are in an assignment, so it's not a statement. * Skip until ";" */ while (tok->str() != ";") { int level = 0; do { if (tok->str() == "(" || tok->str() == "{") ++level; else if (tok->str() == ")" || tok->str() == "}") --level; tok = tok->next(); if (tok == NULL) return; } while (level > 0); } continue; } if (Token::Match(tok, "[;{}] %str%") && !Token::Match(tok->tokAt(2), "[,}]")) { constStatementError(tok->next(), "string"); } if (Token::Match(tok, "[;{}] %num%") && !Token::Match(tok->tokAt(2), "[,}]")) { constStatementError(tok->next(), "numeric"); } } } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- // str plus char //--------------------------------------------------------------------------- void CheckOther::strPlusChar() { 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] == '\'') strPlusChar(tok->next()); // char variable.. unsigned int varid = tok->tokAt(3)->varId(); if (varid > 0 && varid < 10000 && charVars[varid]) strPlusChar(tok->next()); } } } void CheckOther::nullPointerAfterLoop() { // Locate insufficient null-pointer handling after loop for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (! Token::Match(tok, "while ( %var% )")) continue; const unsigned int varid(tok->tokAt(2)->varId()); if (varid == 0) continue; const std::string varname(tok->strAt(2)); // Locate the end of the while loop.. const Token *tok2 = tok->tokAt(4); if (tok2->str() == "{") tok2 = tok2->link(); else { while (tok2 && tok2->str() != ";") tok2 = tok2->next(); } // Goto next token if (tok2) tok2 = tok2->next(); // Check if the variable is dereferenced.. while (tok2) { if (tok2->str() == "{" || tok2->str() == "}" || tok2->str() == "break") break; if (tok2->varId() == varid) { if (tok2->next()->str() == "." || Token::Match(tok2->next(), "= %varid% .", varid)) { // Is this variable a pointer? const Token *tok3 = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid); if (!tok3) break; if (!tok3->previous() || Token::Match(tok3->previous(), "[({};]") || tok3->previous()->isName()) { nullPointerError(tok2, varname); } } break; } tok2 = tok2->next(); } } } void CheckOther::nullPointerLinkedList() { // looping through items in a linked list in a inner loop.. for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next()) { // search for a "for" token.. if (!Token::simpleMatch(tok1, "for (")) continue; if (!Token::simpleMatch(tok1->next()->link(), ") {")) continue; // is there any dereferencing occuring in the for statement.. unsigned int parlevel2 = 1; for (const Token *tok2 = tok1->tokAt(2); tok2; tok2 = tok2->next()) { // Parantheses.. if (tok2->str() == "(") ++parlevel2; else if (tok2->str() == ")") { if (parlevel2 <= 1) break; --parlevel2; } // Dereferencing a variable inside the "for" parantheses.. else if (Token::Match(tok2, "%var% . %var%")) { const unsigned int varid(tok2->varId()); if (varid == 0) continue; if (Token::Match(tok2->tokAt(-2), "%varid% ?", varid)) continue; const std::string varname(tok2->str()); // Check usage of dereferenced variable in the loop.. unsigned int indentlevel3 = 0; for (const Token *tok3 = tok1->next()->link(); tok3; tok3 = tok3->next()) { if (tok3->str() == "{") ++indentlevel3; else if (tok3->str() == "}") { if (indentlevel3 <= 1) break; --indentlevel3; } else if (Token::Match(tok3, "while ( %varid% &&|)", varid)) { // Make sure there is a "break" to prevent segmentation faults.. unsigned int indentlevel4 = indentlevel3; for (const Token *tok4 = tok3->next()->link(); tok4; tok4 = tok4->next()) { if (tok4->str() == "{") ++indentlevel4; else if (tok4->str() == "}") { if (indentlevel4 <= 1) { // Is this variable a pointer? const Token *tempTok = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid); if (tempTok) nullPointerError(tok1, varname, tok3->linenr()); break; } --indentlevel4; } else if (tok4->str() == "break") break; } } } } } } } void CheckOther::nullPointerStructByDeRefAndChec() { // Dereferencing a struct pointer and then checking if it's NULL.. for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next()) { if (Token::Match(tok1, "[{};] %var% = %var% . %var%")) { if (std::string(tok1->strAt(1)) == tok1->strAt(3)) continue; tok1 = tok1->tokAt(3); const unsigned int varid1(tok1->varId()); if (varid1 == 0) continue; const std::string varname(tok1->str()); // Checking if the struct pointer is non-null before the assignment.. { const Token *tok2 = _tokenizer->tokens(); while (tok2) { if (tok2 == tok1) break; if (Token::Match(tok2, "if|while ( !| %varid% )", varid1)) break; tok2 = tok2->next(); } if (tok2 != tok1) continue; } unsigned int indentlevel2 = 0; for (const Token *tok2 = tok1->tokAt(3); tok2; tok2 = tok2->next()) { if (tok2->str() == "{") ++indentlevel2; else if (tok2->str() == "}") { if (indentlevel2 == 0) break; --indentlevel2; } // goto destination.. else if (tok2->isName() && Token::simpleMatch(tok2->next(), ":")) break; // Reassignment of the struct else if (tok2->varId() == varid1) { if (tok2->next()->str() == "=") break; if (Token::Match(tok2->tokAt(-2), "[,(] &")) break; } // Loop.. /** @todo don't bail out if the variable is not used in the loop */ else if (tok2->str() == "do") break; // return at base level => stop checking else if (indentlevel2 == 0 && tok2->str() == "return") break; else if (Token::Match(tok2, "if ( !| %varid% )", varid1)) { // Is this variable a pointer? const Token *tempTok = Token::findmatch(_tokenizer->tokens(), "%type% * %varid% [;)=]", varid1); if (tempTok) nullPointerError(tok1, varname, tok2->linenr()); break; } } } } } void CheckOther::nullPointerByDeRefAndChec() { // Dereferencing a pointer and then checking if it's NULL.. for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (tok->str() == "if" && Token::Match(tok->previous(), "; if ( ! %var% )")) { const unsigned int varid(tok->tokAt(3)->varId()); if (varid == 0) continue; const std::string varname(tok->strAt(3)); const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid%", varid); if (!Token::Match(decltok->tokAt(-3), "[;,(] %var% *")) continue; for (const Token *tok1 = tok->previous(); tok1 && tok1 != decltok; tok1 = tok1->previous()) { if (tok1->varId() == varid) { if (Token::Match(tok1->tokAt(-2), "[=;{}] *")) { nullPointerError(tok1, varname); break; } else if (tok1->previous() && tok1->previous()->str() == "&") { break; } else if (tok1->next() && tok1->next()->str() == "=") { break; } } else if (tok1->str() == "{" || tok1->str() == "}") break; // goto destination.. else if (tok1->isName() && Token::simpleMatch(tok1->next(), ":")) break; } } } } void CheckOther::nullPointer() { nullPointerAfterLoop(); nullPointerLinkedList(); nullPointerStructByDeRefAndChec(); nullPointerByDeRefAndChec(); } /** * \brief parse a function call and extract information about variable usage * \param tok first token * \param var variables that the function read / write. * \param value 0 => invalid with null pointers as parameter. * 1-.. => invalid with uninitialized data. */ static void parseFunctionCall(const Token &tok, std::list &var, unsigned char value) { // standard functions that dereference first parameter.. // both uninitialized data and null pointers are invalid. static std::set functionNames1; if (functionNames1.empty()) { functionNames1.insert("memchr"); functionNames1.insert("memcmp"); functionNames1.insert("strcat"); functionNames1.insert("strncat"); functionNames1.insert("strchr"); functionNames1.insert("strrchr"); functionNames1.insert("strcmp"); functionNames1.insert("strncmp"); functionNames1.insert("strdup"); functionNames1.insert("strndup"); functionNames1.insert("strlen"); functionNames1.insert("strstr"); } // standard functions that dereference second parameter.. // both uninitialized data and null pointers are invalid. static std::set functionNames2; if (functionNames2.empty()) { functionNames2.insert("memcmp"); functionNames2.insert("memcpy"); functionNames2.insert("memmove"); functionNames2.insert("strcat"); functionNames2.insert("strncat"); functionNames2.insert("strcmp"); functionNames2.insert("strncmp"); functionNames2.insert("strcpy"); functionNames2.insert("strncpy"); functionNames2.insert("strstr"); } // 1st parameter.. if (Token::Match(&tok, "%var% ( %var% ,|)") && tok.tokAt(2)->varId() > 0) { if (functionNames1.find(tok.str()) != functionNames1.end()) var.push_back(tok.tokAt(2)); else if (value == 0 && Token::Match(&tok, "memchr|memcmp|memcpy|memmove|memset|strcpy|printf|sprintf|snprintf")) var.push_back(tok.tokAt(2)); else if (Token::simpleMatch(&tok, "fflush")) var.push_back(tok.tokAt(2)); } // 2nd parameter.. if (Token::Match(&tok, "%var% ( %any% , %var% ,|)") && tok.tokAt(4)->varId() > 0) { if (functionNames2.find(tok.str()) != functionNames2.end()) var.push_back(tok.tokAt(4)); } } /// @addtogroup Checks /// @{ /** * @brief %Check for null pointer usage (using ExecutionPath) */ class CheckNullpointer : public ExecutionPath { public: /** Startup constructor */ CheckNullpointer(Check *c) : ExecutionPath(c, 0), null(false) { } private: /** Create checking of specific variable: */ CheckNullpointer(Check *c, const unsigned int id, const std::string &name) : ExecutionPath(c, id), varname(name), null(false) { } /** Copy this check */ ExecutionPath *copy() { return new CheckNullpointer(*this); } /** no implementation => compiler error if used by accident */ void operator=(const CheckNullpointer &); /** variable name for this check (empty => dummy check) */ const std::string varname; /** is this variable null? */ bool null; /** variable is set to null */ static void setnull(std::list &checks, const unsigned int varid) { std::list::iterator it; for (it = checks.begin(); it != checks.end(); ++it) { CheckNullpointer *c = dynamic_cast(*it); if (c && c->varId == varid) c->null = true; } } /** * Dereferencing variable. Check if it is safe (if the variable is null there's an error) * @param checks Checks * @param tok token where dereferencing happens */ static void dereference(std::list &checks, const Token *tok) { const unsigned int varid(tok->varId()); std::list::iterator it; for (it = checks.begin(); it != checks.end(); ++it) { CheckNullpointer *c = dynamic_cast(*it); if (c && c->varId == varid && c->null) { CheckOther *checkOther = dynamic_cast(c->owner); if (checkOther) { checkOther->nullPointerError(tok, c->varname); return; } } } } /** parse tokens */ const Token *parse(const Token &tok, std::list &checks) const { if (Token::Match(tok.previous(), "[;{}] const| %type% * %var% ;")) { const Token * vartok = tok.tokAt(2); if (tok.str() == "const") vartok = vartok->next(); if (vartok->varId() != 0) checks.push_back(new CheckNullpointer(owner, vartok->varId(), vartok->str())); return vartok->next(); } // Template pointer variable.. if (Token::Match(tok.previous(), "[;{}] %type% ::|<")) { const Token * vartok = &tok; while (Token::Match(vartok, "%type% ::")) vartok = vartok->tokAt(2); if (Token::Match(vartok, "%type% < %type%")) { vartok = vartok->tokAt(3); while (vartok && (vartok->str() == "*" || vartok->isName())) vartok = vartok->next(); if (Token::Match(vartok, "> * %var% ;|=")) { vartok = vartok->tokAt(2); checks.push_back(new CheckNullpointer(owner, vartok->varId(), vartok->str())); if (Token::simpleMatch(vartok->next(), "= 0 ;")) setnull(checks, vartok->varId()); return vartok->next(); } } } if (Token::Match(&tok, "%var% (")) { if (tok.str() == "sizeof") return tok.next()->link(); // parse usage.. std::list var; parseFunctionCall(tok, var, 0); for (std::list::const_iterator it = var.begin(); it != var.end(); ++it) dereference(checks, *it); } if (tok.varId() != 0) { if (Token::Match(tok.previous(), "[;{}=] %var% = 0 ;")) setnull(checks, tok.varId()); else if (Token::Match(tok.tokAt(-2), "[;{}=+-/(,] * %var%")) dereference(checks, &tok); else if (Token::Match(tok.tokAt(-2), "return * %var%")) dereference(checks, &tok); else if (!Token::simpleMatch(tok.tokAt(-2), "& (") && Token::Match(tok.next(), ". %var%")) dereference(checks, &tok); else if (Token::Match(tok.previous(), "[;{}=+-/(,] %var% [ %any% ]")) dereference(checks, &tok); else if (Token::Match(tok.previous(), "return %var% [ %any% ]")) dereference(checks, &tok); else if (Token::Match(&tok, "%var% (")) dereference(checks, &tok); else bailOutVar(checks, tok.varId()); } if (Token::simpleMatch(&tok, "* 0")) { if (Token::Match(tok.previous(), "[;{}=+-/(,]") || Token::Match(tok.previous(), "return|<<")) { CheckOther *checkOther = dynamic_cast(owner); if (checkOther) { checkOther->nullPointerError(&tok); } } } return &tok; } /** parse condition. @sa ExecutionPath::parseCondition */ bool parseCondition(const Token &tok, std::list &checks) { if (Token::Match(&tok, "!| %var% (")) { std::list var; parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 0); for (std::list::const_iterator it = var.begin(); it != var.end(); ++it) dereference(checks, *it); } return ExecutionPath::parseCondition(tok, checks); } }; /** * @brief %Check that uninitialized variables aren't used (using ExecutionPath) * */ class CheckUninitVar : public ExecutionPath { public: /** Startup constructor */ CheckUninitVar(Check *c) : ExecutionPath(c, 0), pointer(false), array(false), alloc(false), strncpy_(false) { } private: /** Create a copy of this check */ ExecutionPath *copy() { return new CheckUninitVar(*this); } /** no implementation => compiler error if used */ void operator=(const CheckUninitVar &); /** internal constructor for creating extra checks */ CheckUninitVar(Check *c, unsigned int v, const std::string &name, bool p, bool a) : ExecutionPath(c, v), varname(name), pointer(p), array(a), alloc(false), strncpy_(false) { } /** variable name for this check */ const std::string varname; /** is this variable a pointer? */ const bool pointer; /** is this variable an array? */ const bool array; /** is this variable allocated? */ bool alloc; /** is this variable initialized with strncpy (not always zero-terminated) */ bool strncpy_; /** allocating pointer. For example : p = malloc(10); */ static void alloc_pointer(std::list &checks, unsigned int varid) { std::list::const_iterator it; for (it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid) c->alloc = true; } } /** Initializing a pointer value. For example: *p = 0; */ static void init_pointer(std::list &checks, const Token *tok) { const unsigned int varid(tok->varId()); if (!varid) return; std::list::iterator it = checks.begin(); while (it != checks.end()) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid) { if (c->alloc || c->array) { delete c; checks.erase(it++); continue; } else { use_pointer(checks, tok); } } ++it; } } /** Deallocate a pointer. For example: free(p); */ static void dealloc_pointer(std::list &checks, const Token *tok) { const unsigned int varid(tok->varId()); if (!varid) return; std::list::const_iterator it; for (it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid) { if (c->pointer && !c->alloc) { CheckOther *checkOther = dynamic_cast(c->owner); if (checkOther) { checkOther->uninitvarError(tok, c->varname); break; } } c->alloc = false; } } } /** * Pointer assignment: p = x; * if p is a pointer and x is an array/pointer then bail out * \param checks all available checks * \param tok1 the "p" token * \param tok2 the "x" token */ static void pointer_assignment(std::list &checks, const Token *tok1, const Token *tok2) { const unsigned int varid1(tok1->varId()); if (varid1 == 0) return; const unsigned int varid2(tok2->varId()); if (varid2 == 0) return; std::list::const_iterator it; // bail out if first variable is a pointer for (it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid1 && c->pointer) { bailOutVar(checks, varid1); break; } } // bail out if second variable is a array/pointer for (it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid2 && (c->pointer || c->array)) { bailOutVar(checks, varid2); break; } } } /** Initialize an array with strncpy. */ static void init_strncpy(std::list &checks, const Token *tok) { const unsigned int varid(tok->varId()); if (!varid) return; std::list::const_iterator it; for (it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid) { c->strncpy_ = true; } } } /** * use - called from the use* functions below. * @param checks all available checks * @param tok variable token * @param mode specific behaviour * @return if error is found, true is returned */ static bool use(std::list &checks, const Token *tok, const int mode) { const unsigned int varid(tok->varId()); if (varid == 0) return false; std::list::const_iterator it; for (it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varId == varid) { // mode 0 : the variable is used "directly" // example: .. = var; // it is ok to read the address of an uninitialized array. // it is ok to read the address of an allocated pointer if (mode == 0 && (c->array || (c->pointer && c->alloc))) continue; // mode 2 : bad usage of pointer. if it's not a pointer then the usage is ok. // example: ptr->foo(); if (mode == 2 && !c->pointer) continue; // mode 3 : using dead pointer is invalid. if (mode == 3 && (!c->pointer || c->alloc)) continue; // mode 4 : reading uninitialized array or pointer is invalid. if (mode == 4 && (!c->array && !c->pointer)) continue; CheckOther *checkOther = dynamic_cast(c->owner); if (checkOther) { if (c->strncpy_) checkOther->uninitstringError(tok, c->varname); else if (c->pointer && c->alloc) checkOther->uninitdataError(tok, c->varname); else checkOther->uninitvarError(tok, c->varname); return true; } } } // No error found return false; } /** * Reading variable. Use this function in situations when it is * invalid to read the data of the variable but not the address. * @param checks all available checks * @param tok variable token * @return if error is found, true is returned */ static bool use(std::list &checks, const Token *tok) { return use(checks, tok, 0); } /** * Reading array elements. If the variable is not an array then the usage is ok. * @param checks all available checks * @param tok variable token */ static void use_array(std::list &checks, const Token *tok) { use(checks, tok, 1); } /** * Bad pointer usage. If the variable is not a pointer then the usage is ok. * @param checks all available checks * @param tok variable token */ static bool use_pointer(std::list &checks, const Token *tok) { return use(checks, tok, 2); } /** * Using variable.. if it's a dead pointer the usage is invalid. * @param checks all available checks * @param tok variable token */ static bool use_dead_pointer(std::list &checks, const Token *tok) { return use(checks, tok, 3); } /** * Using variable.. reading from uninitialized array or pointer data is invalid. * Example: = x[0]; * @param checks all available checks * @param tok variable token */ static bool use_array_or_pointer_data(std::list &checks, const Token *tok) { return use(checks, tok, 4); } /** declaring a variable */ void declare(std::list &checks, const Token *vartok, const Token &tok, const bool p, const bool a) const { if (vartok->varId() == 0) return; bool isenum = false; if (!tok.isStandardType()) { const std::string pattern("enum " + tok.str()); for (const Token *tok2 = tok.previous(); tok2; tok2 = tok2->previous()) { if (tok2->str() != "{") continue; if (Token::simpleMatch(tok2->tokAt(-2), pattern.c_str())) { isenum = true; break; } } } // Suppress warnings if variable in inner scope has same name as variable in outer scope if (!tok.isStandardType() && !isenum) { std::set dup; for (std::list::const_iterator it = checks.begin(); it != checks.end(); ++it) { CheckUninitVar *c = dynamic_cast(*it); if (c && c->varname == vartok->str() && c->varId != vartok->varId()) dup.insert(c->varId); } if (!dup.empty()) { for (std::set::const_iterator it = dup.begin(); it != dup.end(); ++it) bailOutVar(checks, *it); return; } } if (a || p || tok.isStandardType() || isenum) checks.push_back(new CheckUninitVar(owner, vartok->varId(), vartok->str(), p, a)); } /** parse tokens. @sa ExecutionPath::parse */ const Token *parse(const Token &tok, std::list &checks) const { // Variable declaration.. if (tok.isName() && tok.str() != "return") { if (Token::Match(&tok, "enum %type% {")) return tok.tokAt(2)->link(); if (Token::Match(tok.previous(), "[;{}] %type% *| %var% ;")) { const Token * vartok = tok.next(); const bool p(vartok->str() == "*"); if (p) vartok = vartok->next(); declare(checks, vartok, tok, p, false); return vartok; } // Variable declaration for array.. if (Token::Match(tok.previous(), "[;{}] %type% %var% [ %num% ] ;")) { const Token * vartok = tok.next(); declare(checks, vartok, tok, false, true); return vartok->next()->link(); } // Template pointer variable.. if (Token::Match(tok.previous(), "[;{}] %type% ::|<")) { const Token * vartok = &tok; while (Token::Match(vartok, "%type% ::")) vartok = vartok->tokAt(2); if (Token::Match(vartok, "%type% < %type%")) { vartok = vartok->tokAt(3); while (vartok && (vartok->str() == "*" || vartok->isName())) vartok = vartok->next(); if (Token::Match(vartok, "> * %var% ;")) { declare(checks, vartok->tokAt(2), tok, true, false); return vartok->tokAt(2); } } } } if (tok.varId()) { // Used.. if (Token::Match(tok.previous(), "[[(,+-*/] %var% []),+-*/]")) { use(checks, &tok); return &tok; } if (Token::Match(tok.previous(), "++|--") || Token::Match(tok.next(), "++|--")) { use(checks, &tok); return &tok; } if (Token::Match(tok.previous(), "[;{}] %var% =|[")) { // check variable usages in rhs/index for (const Token *tok2 = tok.tokAt(2); tok2; tok2 = tok2->next()) { if (Token::Match(tok2, ";|)|=")) break; if (Token::Match(tok2, "%var% (")) break; if (tok2->varId() && !Token::Match(tok2->previous(), "&|::") && !Token::simpleMatch(tok2->next(), "=")) { bool foundError; if (tok2->next()->str() == "[") foundError = use_array_or_pointer_data(checks, tok2); else foundError = use(checks, tok2); // prevent duplicate error messages if (foundError) { bailOutVar(checks, tok2->varId()); } } } // pointer aliasing? if (Token::Match(tok.tokAt(2), "%var% ;")) { pointer_assignment(checks, &tok, tok.tokAt(2)); } } if (Token::simpleMatch(tok.next(), "(")) { use_pointer(checks, &tok); } if (Token::Match(tok.tokAt(-2), "[;{}] *")) { if (Token::simpleMatch(tok.next(), "=")) init_pointer(checks, &tok); else use_pointer(checks, &tok); return &tok; } // += etc if (Token::Match(tok.previous(), "[;{}]") || Token::Match(tok.tokAt(-2), "[;{}] *")) { // goto the equal.. const Token *eq = tok.next(); if (eq && eq->str() == "[" && eq->link() && eq->link()->next()) eq = eq->link()->next(); // is it X= if (Token::Match(eq, "+=|-=|*=|/=|&=|^=") || eq->str() == "|=") { if (tok.previous()->str() == "*") use_pointer(checks, &tok); else if (tok.next()->str() == "[") use_array(checks, &tok); else use(checks, &tok); } } if (Token::Match(tok.next(), "= malloc|kmalloc") || Token::simpleMatch(tok.next(), "= new char [")) { alloc_pointer(checks, tok.varId()); if (tok.tokAt(3)->str() == "(") return tok.tokAt(3)->link(); } else if (Token::simpleMatch(tok.previous(), ">>") || Token::simpleMatch(tok.next(), "=")) { ExecutionPath::bailOutVar(checks, tok.varId()); return &tok; } if (Token::simpleMatch(tok.next(), "[")) { const Token *tok2 = tok.next()->link(); if (Token::simpleMatch(tok2 ? tok2->next() : 0, "=")) { ExecutionPath::bailOutVar(checks, tok.varId()); return &tok; } } if (Token::simpleMatch(tok.previous(), "delete") || Token::simpleMatch(tok.tokAt(-3), "delete [ ]")) { dealloc_pointer(checks, &tok); return &tok; } } if (Token::Match(&tok, "%var% (") && uvarFunctions.find(tok.str()) == uvarFunctions.end()) { if (Token::simpleMatch(&tok, "sizeof (")) return tok.next()->link(); // deallocate pointer if (Token::Match(&tok, "free|kfree|fclose ( %var% )")) { dealloc_pointer(checks, tok.tokAt(2)); return tok.tokAt(3); } // parse usage.. { std::list var; parseFunctionCall(tok, var, 1); for (std::list::const_iterator it = var.begin(); it != var.end(); ++it) use_array(checks, *it); } // strncpy doesn't 0-terminate first parameter if (Token::Match(&tok, "strncpy ( %var% ,")) { init_strncpy(checks, tok.tokAt(2)); return tok.next()->link(); } if (Token::Match(&tok, "asm ( )")) { ExecutionPath::bailOut(checks); return &tok; } // is the variable passed as a parameter to some function? unsigned int parlevel = 0; std::set bailouts; for (const Token *tok2 = tok.next(); tok2; tok2 = tok2->next()) { if (tok2->str() == "(") ++parlevel; else if (tok2->str() == ")") { if (parlevel <= 1) break; --parlevel; } else if (Token::simpleMatch(tok2, "sizeof (")) { tok2 = tok2->next()->link(); if (!tok2) break; } else if (tok2->varId()) { if (Token::Match(tok2->tokAt(-2), "[(,] *") || Token::Match(tok2->next(), ". %var%")) use_dead_pointer(checks, tok2); // it is possible that the variable is initialized here bailouts.insert(tok2->varId()); } } for (std::set::const_iterator it = bailouts.begin(); it != bailouts.end(); ++it) ExecutionPath::bailOutVar(checks, *it); } // function call via function pointer if (Token::Match(&tok, "( * %var% ) (")) { // is the variable passed as a parameter to some function? unsigned int parlevel = 0; for (const Token *tok2 = tok.link()->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == "(") ++parlevel; else if (tok2->str() == ")") { if (parlevel <= 1) break; --parlevel; } else if (tok2->varId()) { // it is possible that the variable is initialized here ExecutionPath::bailOutVar(checks, tok2->varId()); } } } if (tok.str() == "return") { // Todo: if (!array && .. if (Token::Match(tok.next(), "%var% ;")) { use(checks, tok.next()); } } if (tok.varId()) { if (Token::simpleMatch(tok.previous(), "=")) { if (Token::Match(tok.tokAt(-3), "& %var% =")) { bailOutVar(checks, tok.varId()); return &tok; } if (!Token::Match(tok.tokAt(-3), ". %var% =")) { if (!Token::Match(tok.tokAt(-3), "[;{}] %var% =")) { use(checks, &tok); return &tok; } const unsigned int varid2 = tok.tokAt(-2)->varId(); if (varid2) { /* const Token *tok2 = Token::findmatch(owner->_tokenizer->tokens(), "%varid%", varid2); if (tok2 && !Token::simpleMatch(tok2->previous(), "*")) */ { use(checks, &tok); return &tok; } } } } if (Token::simpleMatch(tok.next(), ".")) { const Token *tok2 = tok.next(); while (Token::Match(tok2, ". %var%")) tok2 = tok2->tokAt(2); if (tok2 && tok2->str() != "=") use_pointer(checks, &tok); else bailOutVar(checks, tok.varId()); return &tok; } if (Token::simpleMatch(tok.next(), "[")) { ExecutionPath::bailOutVar(checks, tok.varId()); return &tok; } if (Token::Match(tok.tokAt(-2), "[,(=] *")) { use_pointer(checks, &tok); return &tok; } if (Token::simpleMatch(tok.previous(), "&")) { ExecutionPath::bailOutVar(checks, tok.varId()); } } // Parse "for" if (Token::Match(&tok, "[;{}] for (")) { // initialized variables std::set varid1; varid1.insert(0); // Parse token const Token *tok2; // parse setup for (tok2 = tok.tokAt(3); tok2; tok2 = tok2->next()) { if (tok2->str() == ";") break; if (tok2->varId()) varid1.insert(tok2->varId()); } // parse condition if (Token::Match(tok2, "; %var% <|<=|>=|> %num% ;")) { // If the variable hasn't been initialized then call "use" if (varid1.find(tok2->next()->varId()) == varid1.end()) use(checks, tok2->next()); } // goto stepcode tok2 = tok2->next(); while (tok2 && tok2->str() != ";") tok2 = tok2->next(); // parse the stepcode if (Token::Match(tok2, "; ++|-- %var% ) {") || Token::Match(tok2, "; %var% ++|-- ) {")) { // get id of variable.. unsigned int varid = tok2->next()->varId(); if (!varid) varid = tok2->tokAt(2)->varId(); // Check that the variable hasn't been initialized and // that it isn't initialized in the body.. if (varid1.find(varid) == varid1.end()) { unsigned int indentlevel = 0; for (const Token *tok3 = tok2->tokAt(5); tok3; tok3 = tok3->next()) { if (tok3->str() == "{") ++indentlevel; else if (tok3->str() == "}") { if (indentlevel == 0) break; --indentlevel; } if (tok3->varId() == varid) { varid = 0; // variable is used.. maybe it's initialized. clear the variable id. break; } } // If the variable isn't initialized in the body call "use" if (varid != 0) { // goto variable tok2 = tok2->next(); if (!tok2->varId()) tok2 = tok2->next(); // call "use" use(checks, tok2); } } } } return &tok; } bool parseCondition(const Token &tok, std::list &checks) { if (tok.varId() && Token::Match(&tok, "%var% <|<=|==|!=|)|[")) use(checks, &tok); else if (Token::Match(&tok, "!| %var% (")) { std::list var; parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 1); for (std::list::const_iterator it = var.begin(); it != var.end(); ++it) use_array(checks, *it); } else if (Token::Match(&tok, "! %var% )")) { use(checks, &tok); return false; } return ExecutionPath::parseCondition(tok, checks); } public: /** Functions that don't handle uninitialized variables well */ static std::set uvarFunctions; static void analyseFunctions(const Token * const tokens, std::set &func, bool showAll) { for (const Token *tok = tokens; tok; tok = tok->next()) { if (tok->str() == "{") { tok = tok->link(); continue; } if (tok->str() != "::" && Token::Match(tok->next(), "%var% ( %type%")) { if (!Token::simpleMatch(tok->tokAt(2)->link(), ") {")) continue; const Token *tok2 = tok->tokAt(3); while (tok2 && tok2->str() != ")") { if (tok2->str() == ",") tok2 = tok2->next(); if (Token::Match(tok2, "%type% %var% ,|)") && tok2->isStandardType()) { tok2 = tok2->tokAt(2); continue; } if (tok2->isStandardType() && Token::Match(tok2, "%type% & %var% ,|)")) { const unsigned int varid(tok2->tokAt(2)->varId()); // flags for read/write bool r = false, w = false; // check how the variable is used in the function unsigned int indentlevel = 0; for (const Token *tok3 = tok2; tok3; tok3 = tok3->next()) { if (tok3->str() == "{") ++indentlevel; else if (tok3->str() == "}") { if (indentlevel <= 1) break; --indentlevel; } else if (indentlevel == 0 && tok3->str() == ";") break; else if (indentlevel >= 1 && tok3->varId() == varid) { if (Token::Match(tok3->previous(), "++|--") || Token::Match(tok3->next(), "++|--")) { r = true; } // --all else if (showAll) { if (!Token::simpleMatch(tok3->next(), "=")) r = true; else { w = true; break; } } else { w = true; break; } } } if (!r || w) break; tok2 = tok2->tokAt(3); continue; } if (Token::Match(tok2, "const %type% &|*| const| %var% ,|)") && tok2->next()->isStandardType()) { tok2 = tok2->tokAt(3); while (tok2->isName()) tok2 = tok2->next(); continue; } break; } // found simple function.. if (tok2->link() == tok->tokAt(2)) func.insert(tok->next()->str()); } } } }; /** Functions that don't handle uninitialized variables well */ std::set CheckUninitVar::uvarFunctions; /// @} void CheckOther::analyseFunctions(const Token * const tokens, std::set &func, bool showAll) { CheckUninitVar::analyseFunctions(tokens, func, showAll); } void CheckOther::executionPaths() { // Check for null pointer errors.. { CheckNullpointer c(this); checkExecutionPaths(_tokenizer->tokens(), &c); } // check if variable is accessed uninitialized.. { // no writing if multiple threads are used (TODO: thread safe analysis?) if (_settings->_jobs == 1) CheckUninitVar::analyseFunctions(_tokenizer->tokens(), CheckUninitVar::uvarFunctions, _settings->inconclusive); CheckUninitVar c(this); checkExecutionPaths(_tokenizer->tokens(), &c); } } 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->tokAt(4)->str()) && MathLib::toLongNumber(tok->tokAt(4)->str()) == 0L) { zerodivError(tok); } } } void CheckOther::checkMathFunctions() { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { // case log(-2) if (Token::Match(tok, "log|log10 ( %num% )") && MathLib::isNegative(tok->tokAt(2)->str()) && MathLib::isInt(tok->tokAt(2)->str()) && MathLib::toLongNumber(tok->tokAt(2)->str()) <= 0) { mathfunctionCallError(tok); } // case log(-2.0) else if (Token::Match(tok, "log|log10 ( %num% )") && MathLib::isNegative(tok->tokAt(2)->str()) && MathLib::isFloat(tok->tokAt(2)->str()) && MathLib::toDoubleNumber(tok->tokAt(2)->str()) <= 0.) { mathfunctionCallError(tok); } // case log(0.0) else if (Token::Match(tok, "log|log10 ( %num% )") && !MathLib::isNegative(tok->tokAt(2)->str()) && MathLib::isFloat(tok->tokAt(2)->str()) && MathLib::toDoubleNumber(tok->tokAt(2)->str()) <= 0.) { mathfunctionCallError(tok); } // case log(0) else if (Token::Match(tok, "log|log10 ( %num% )") && !MathLib::isNegative(tok->tokAt(2)->str()) && MathLib::isInt(tok->tokAt(2)->str()) && MathLib::toLongNumber(tok->tokAt(2)->str()) <= 0) { mathfunctionCallError(tok); } // acos( x ), asin( x ) where x is defined for intervall [-1,+1], but not beyound else if (Token::Match(tok, "acos|asin ( %num% )") && std::fabs(MathLib::toDoubleNumber(tok->tokAt(2)->str())) > 1.0) { mathfunctionCallError(tok); } // sqrt( x ): if x is negative the result is undefined else if (Token::Match(tok, "sqrt ( %num% )") && MathLib::isNegative(tok->tokAt(2)->str())) { mathfunctionCallError(tok); } // atan2 ( x , y): x and y can not be zero, because this is mathematically not defined else if (Token::Match(tok, "atan2 ( %num% , %num% )") && MathLib::isNullValue(tok->tokAt(2)->str()) && MathLib::isNullValue(tok->tokAt(4)->str())) { 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 (Token::Match(tok, "fmod ( %num% , %num% )") && MathLib::isNullValue(tok->tokAt(4)->str())) { mathfunctionCallError(tok, 2); } // pow ( x , y) If x is zero, and y is negative --> division by zero else if (Token::Match(tok, "pow ( %num% , %num% )") && MathLib::isNullValue(tok->tokAt(2)->str()) && MathLib::isNegative(tok->tokAt(4)->str())) { mathfunctionCallError(tok, 2); } } } void CheckOther::postIncrement() { if (!_settings->_checkCodingStyle || !_settings->inconclusive) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "for (")) { const Token *tok2 = tok->next()->link(); if (tok2) tok2 = tok2->tokAt(-3); if (Token::Match(tok2, "; %var% ++|-- )")) { if (tok2->next()->varId() == 0) continue; // Take a look at the variable declaration const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid%", tok2->tokAt(1)->varId()); const std::string classDef = std::string("class ") + std::string(decltok->previous()->strAt(0)); // Is the variable an iterator? if (decltok && Token::Match(decltok->previous(), "iterator|const_iterator")) postIncrementError(tok2, tok2->strAt(1), (std::string("++") == tok2->strAt(2))); // Is the variable a class? else if (Token::findmatch(_tokenizer->tokens(), classDef.c_str())) postIncrementError(tok2, tok2->strAt(1), (std::string("++") == tok2->strAt(2))); } } } } void CheckOther::cstyleCastError(const Token *tok) { reportError(tok, Severity::style, "cstyleCast", "C-style pointer casting"); } void CheckOther::redundantIfDelete0Error(const Token *tok) { reportError(tok, Severity::style, "redundantIfDelete0", "Redundant condition. It is safe to deallocate a NULL pointer"); } void CheckOther::redundantIfRemoveError(const Token *tok) { reportError(tok, Severity::style, "redundantIfRemove", "Redundant condition. The remove function in the STL will not do anything if element doesn't exist"); } 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 behaviour: " + varname + " is used wrong in call to sprintf or snprintf. Quote: If copying takes place between objects that overlap as a result of a call to sprintf() or snprintf(), the results are undefined."); } void CheckOther::udivError(const Token *tok) { reportError(tok, Severity::error, "udivError", "Unsigned division. The result will be wrong."); } void CheckOther::udivWarning(const Token *tok) { reportError(tok, Severity::possibleStyle, "udivWarning", "Division with signed and unsigned operators"); } void CheckOther::unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname) { reportError(tok, Severity::style, "unusedStructMember", "struct or union member '" + structname + "::" + varname + "' is never used"); } void CheckOther::passedByValueError(const Token *tok, const std::string &parname) { reportError(tok, Severity::style, "passedByValue", "Function parameter '" + parname + "' is passed by value. It could be passed by reference instead."); } void CheckOther::constStatementError(const Token *tok, const std::string &type) { reportError(tok, Severity::style, "constStatement", "Redundant code: Found a statement that begins with " + type + " constant"); } void CheckOther::charArrayIndexError(const Token *tok) { reportError(tok, Severity::style, "charArrayIndex", "Warning - using char variable as array index"); } void CheckOther::charBitOpError(const Token *tok) { reportError(tok, Severity::style, "charBitOp", "Warning - using char variable in bit operation"); } void CheckOther::variableScopeError(const Token *tok, const std::string &varname) { reportError(tok, Severity::style, "variableScope", "The scope of the variable " + varname + " can be reduced"); } void CheckOther::conditionAlwaysTrueFalse(const Token *tok, const std::string &truefalse) { reportError(tok, Severity::style, "conditionAlwaysTrueFalse", "Condition is always " + truefalse); } void CheckOther::strPlusChar(const Token *tok) { reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic"); } void CheckOther::nullPointerError(const Token *tok) { reportError(tok, Severity::error, "nullPointer", "Null pointer dereference"); } void CheckOther::nullPointerError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname); } void CheckOther::nullPointerError(const Token *tok, const std::string &varname, const int line) { reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname + " - otherwise it is redundant to check if " + varname + " is null at line " + MathLib::toString(line)); } void CheckOther::uninitstringError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "uninitstring", "Dangerous usage of '" + varname + "' (strncpy doesn't always 0-terminate it)"); } void CheckOther::uninitdataError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "uninitdata", "Data is allocated but not initialized: " + varname); } void CheckOther::uninitvarError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "uninitvar", "Uninitialized variable: " + varname); } void CheckOther::zerodivError(const Token *tok) { reportError(tok, Severity::error, "zerodiv", "Division by zero"); } void CheckOther::mathfunctionCallError(const Token *tok, const unsigned int numParam) { if (tok) { if (numParam == 1) reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->tokAt(2)->str() + " to " + tok->str() + "() leads to undefined result"); else if (numParam == 2) reportError(tok, Severity::error, "wrongmathcall", "Passing value " + tok->tokAt(2)->str() + " and " + tok->tokAt(4)->str() + " to " + tok->str() + "() leads to undefined result"); } else reportError(tok, Severity::error, "wrongmathcall", "Passing value " " to " "() leads to undefined result"); } void CheckOther::postIncrementError(const Token *tok, const std::string &var_name, const bool isIncrement) { std::string type = (isIncrement ? "Incrementing" : "Decrementing"); reportError(tok, Severity::possibleStyle, "postIncrementDecrement", ("Pre-" + type + " variable '" + var_name + "' is preferred to Post-" + type)); } void CheckOther::emptyStringTestError(const Token *tok, const std::string &var_name, const bool isTestForEmpty) { if (isTestForEmpty) { reportError(tok, Severity::possibleStyle, "emptyStringTest", "Empty string test can be simplified to \"*" + var_name + " == '\\0'\""); } else { reportError(tok, Severity::possibleStyle, "emptyStringTest", "Non-empty string test can be simplified to \"*" + var_name + " != '\\0'\""); } }