/* * Cppcheck - A tool for static C/C++ code analysis * Copyright (C) 2007-2013 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 // 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(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "%var% ++")) { if (tok->varId()) { const Variable *var = tok->variable(); if (var && var->typeEndToken()->str() == "bool") incrementBooleanError(tok); } } } } } void CheckOther::incrementBooleanError(const Token *tok) { reportError( tok, Severity::style, "incrementboolean", "Incrementing a variable of type 'bool' with postfix operator++ is deprecated by the C++ Standard. You should assign it the value 'true' instead.\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. You should assign it the value 'true' instead." ); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::clarifyCalculation() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->str() == "?") { // condition const Token *cond = tok->previous(); 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->previous()) { if ((cond->isName() || cond->isNumber()) && cond->previous()->str() == "*") cond = cond->tokAt(-2); else if (cond->str() == ")") cond = cond->link()->previous(); else break; } if (!cond) continue; // first multiplication operand if (cond->str() == ")") { clarifyCalculationError(cond, op); } else if (cond->isName() || cond->isNumber()) { if (Token::Match(cond->previous(),"return|=|+|-|,|(") || cond->strAt(-1) == op) 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; const bool isC = _tokenizer->isC(); const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; 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 (tok2->type() == Token::eComparisonOp) { // This might be a template if (!isC && tok2->link()) 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 (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "%comp%|!")) { if (tok->link()) // don't write false positives when templates are used continue; 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(tok2, "&|* ,|>") || Token::simpleMatch(tok2->previous(), "const &")) continue; // #3609 - CWinTraits::.. if (!isC && Token::Match(tok->previous(), "%var% <")) { const Token *tok3 = tok2; while (Token::Match(tok3, "[&|^] %var%")) tok3 = tok3->tokAt(2); if (Token::Match(tok3, ",|>")) 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); Clarify expression 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); Clarify expression 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); } //--------------------------------------------------------------------------- // Clarify (meaningless) statements like *foo++; with parentheses. //--------------------------------------------------------------------------- void CheckOther::clarifyStatement() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "* %var%")) { const Token *tok2=tok->previous(); while (tok2 && tok2->str() == "*") tok2=tok2->previous(); if (Token::Match(tok2, "[{};]")) { tok = tok->tokAt(2); for (;;) { if (tok->str() == "[") tok = tok->link()->next(); if (Token::Match(tok, ".|:: %var%")) { if (tok->strAt(2) == "(") tok = tok->linkAt(2)->next(); else tok = tok->tokAt(2); } else break; } if (Token::Match(tok, "++|-- [;,]")) clarifyStatementError(tok); } } } } } void CheckOther::clarifyStatementError(const Token *tok) { reportError(tok, Severity::warning, "clarifyStatement", "Ineffective statement similar to '*A++;'. Did you intend to write '(*A)++;'?\n" "A statement like '*A++;' might not do what you intended. Postfix 'operator++' is executed before 'operator*'. " "Thus, the dereference is meaningless. Did you intend to write '(*A)++;'?"); } //--------------------------------------------------------------------------- // 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; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "(|.|return|&&|%oror%|throw|, %var% [&|]")) { const Variable *var = tok->next()->variable(); if (var && var->typeEndToken()->str() == "bool") { bitwiseOnBooleanError(tok->next(), var->name(), tok->strAt(2) == "&" ? "&&" : "||"); tok = tok->tokAt(2); } } else if (Token::Match(tok, "[&|] %var% )|.|return|&&|%oror%|throw|,") && (!tok->previous() || !tok->previous()->isExtendedOp() || tok->strAt(-1) == ")")) { const Variable *var = tok->next()->variable(); if (var && var->typeEndToken()->str() == "bool") { bitwiseOnBooleanError(tok->next(), var->name(), tok->str() == "&" ? "&&" : "||"); tok = tok->tokAt(2); } } } } } void CheckOther::bitwiseOnBooleanError(const Token *tok, const std::string &varname, const std::string &op) { reportError(tok, Severity::style, "bitwiseOnBoolean", "Boolean variable '" + varname + "' is used in bitwise operation. Did you mean '" + op + "'?", true); } void CheckOther::checkSuspiciousSemicolon() { if (!_settings->inconclusive || !_settings->isEnabled("style")) return; const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase(); // Look for "if(); {}", "for(); {}" or "while(); {}" for (std::list::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) { if (i->type == Scope::eIf || i->type == Scope::eElse || i->type == Scope::eElseIf || i->type == Scope::eWhile || i->type == Scope::eFor) { // 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(i->classStart, "{ ; } {") && i->classStart->previous()->linenr() == i->classStart->tokAt(2)->linenr() && i->classStart->linenr()+1 >= i->classStart->tokAt(3)->linenr()) { SuspiciousSemicolonError(i->classStart); } } } } void CheckOther::SuspiciousSemicolonError(const Token* tok) { reportError(tok, Severity::warning, "suspiciousSemicolon", "Suspicious use of ; at the end of 'if/for/while' statement.", true); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::warningOldStylePointerCast() { // Only valid on C++ code if (!_settings->isEnabled("style") || !_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; if (tok->strAt(1) == "const") tok = tok->next(); if (tok->strAt(4) == "const") continue; // Is "type" a class? const std::string pattern("class|struct " + tok->strAt(1)); if (Token::findmatch(_tokenizer->tokens(), pattern.c_str(), tok)) cstyleCastError(tok); } } void CheckOther::cstyleCastError(const Token *tok) { reportError(tok, Severity::style, "cstyleCast", "C-style pointer casting"); } //--------------------------------------------------------------------------- // float* f; double* d = (double*)f; <-- Pointer cast to a type with an incompatible binary data representation //--------------------------------------------------------------------------- static std::string analyzeType(const Token* tok) { if (tok->str() == "double") { if (tok->isLong()) return "long double"; else return "double"; } if (tok->str() == "float") return "float"; if (Token::Match(tok, "int|long|short|char|size_t")) return "integer"; return ""; } void CheckOther::invalidPointerCast() { if (!_settings->isEnabled("style") && !_settings->isEnabled("portability")) return; const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { const Token* toTok = 0; const Token* nextTok = 0; // Find cast if (Token::Match(tok, "( const| %type% const| * )") || Token::Match(tok, "( const| %type% %type% const| * )")) { toTok = tok->next(); nextTok = tok->link()->next(); if (nextTok && nextTok->str() == "(") nextTok = nextTok->next(); } else if (Token::Match(tok, "reinterpret_cast < const| %type% const| * > (") || Token::Match(tok, "reinterpret_cast < const| %type% %type% const| * > (")) { nextTok = tok->tokAt(5); while (nextTok->str() != "(") nextTok = nextTok->next(); nextTok = nextTok->next(); toTok = tok->tokAt(2); } if (toTok && toTok->str() == "const") toTok = toTok->next(); if (!nextTok || !toTok || !toTok->isStandardType()) continue; // Find casted variable const Variable *var = 0; bool allocation = false; bool ref = false; if (Token::Match(nextTok, "new %type%")) allocation = true; else if (Token::Match(nextTok, "%var% !![")) var = nextTok->variable(); else if (Token::Match(nextTok, "& %var%") && !Token::Match(nextTok->tokAt(2), "(|[")) { var = nextTok->next()->variable(); ref = true; } const Token* fromTok = 0; if (allocation) { fromTok = nextTok->next(); } else { if (!var || (!ref && !var->isPointer() && !var->isArray()) || (ref && (var->isPointer() || var->isArray()))) continue; fromTok = var->typeStartToken(); } while (Token::Match(fromTok, "static|const")) fromTok = fromTok->next(); if (!fromTok->isStandardType()) continue; std::string fromType = analyzeType(fromTok); std::string toType = analyzeType(toTok); if (fromType != toType && !fromType.empty() && !toType.empty() && (toType != "integer" || _settings->isEnabled("portability")) && (toTok->str() != "char" || _settings->inconclusive)) invalidPointerCastError(tok, fromType, toType, toTok->str() == "char"); } } } void CheckOther::invalidPointerCastError(const Token* tok, const std::string& from, const std::string& to, bool inconclusive) { if (to == "integer") { // If we cast something to int*, this can be useful to play with its binary data representation if (!inconclusive) reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to integer* is not portable due to different binary data representations on different platforms."); else reportError(tok, Severity::portability, "invalidPointerCast", "Casting from " + from + "* to char* is not portable due to different binary data representations on different platforms.", true); } else reportError(tok, Severity::warning, "invalidPointerCast", "Casting between " + from + "* and " + to + "* which have an incompatible binary data representation."); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkSizeofForNumericParameter() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; 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::warning, "sizeofwithnumericparameter", "Suspicious usage of 'sizeof' with a numeric constant as parameter.\n" "It is unusual to use a constant value with sizeof. For example, 'sizeof(10)'" " returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 10. 'sizeof('A')'" " and 'sizeof(char)' can return different results."); } //--------------------------------------------------------------------------- // This check detects errors on POSIX systems, when a pipe command called // with a wrong dimensioned file descriptor array. The pipe command requires // exactly an integer array of dimension two as parameter. // // References: // - http://linux.die.net/man/2/pipe // - ticket #3521 //--------------------------------------------------------------------------- void CheckOther::checkPipeParameterSize() { if (!_settings->isEnabled("warning") || !_settings->standards.posix) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "pipe ( %var% )") || Token::Match(tok, "pipe2 ( %var% ,")) { const Token * const varTok = tok->tokAt(2); const Variable *var = varTok->variable(); MathLib::bigint dim; if (var && (var->isArray() || var->isPointer()) && ((dim=var->dimension(0U)) < 2)) { const std::string strDim = MathLib::longToString(dim); checkPipeParameterSizeError(varTok,varTok->str(), strDim); } } } } } void CheckOther::checkPipeParameterSizeError(const Token *tok, const std::string &strVarName, const std::string &strDim) { reportError(tok, Severity::error, "wrongPipeParameterSize", "Variable " + strVarName + " must have size 2 when it is used as parameter of pipe() command.\n" "The pipe()/pipe2() system command takes an argument, which is an array of exactly two integers." "\nThe variable " + strVarName + " is an array of size " + strDim + ", which does not match." ); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkSizeofForArrayParameter() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "sizeof ( %var% )") || Token::Match(tok, "sizeof %var% !![")) { const Token* varTok = tok->next(); if (varTok->str() == "(") { varTok = varTok->next(); } if (varTok->varId() > 0) { const Variable *var = varTok->variable(); if (var && var->isArray() && var->isArgument()) { sizeofForArrayParameterError(tok); } } } } } } void CheckOther::sizeofForArrayParameterError(const Token *tok) { reportError(tok, Severity::error, "sizeofwithsilentarraypointer", "Using 'sizeof' on array given as function argument " "returns size of a pointer.\n" "Using 'sizeof' for array given as function argument returns the size of a pointer. " "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::checkSizeofForPointerSize() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { const Token *tokVar; const Token *variable; const Token *variable2 = 0; // Find any function that may use sizeof on a pointer // Once leaving those tests, it is mandatory to have: // - variable matching the used pointer // - tokVar pointing on the argument where sizeof may be used if (Token::Match(tok, "[*;{}] %var% = malloc|alloca (")) { variable = tok->next(); tokVar = tok->tokAt(5); } else if (Token::Match(tok, "[*;{}] %var% = calloc (")) { variable = tok->next(); tokVar = tok->tokAt(5)->nextArgument(); } else if (Token::simpleMatch(tok, "memset (")) { variable = tok->tokAt(2); tokVar = variable->tokAt(2)->nextArgument(); // The following tests can be inconclusive in case the variable in sizeof // is constant string by intention } else if (!_settings->inconclusive) { continue; } else if (Token::Match(tok, "memcpy|memcmp|memmove|strncpy|strncmp|strncat (")) { variable = tok->tokAt(2); variable2 = variable->nextArgument(); tokVar = variable2->nextArgument(); } else { continue; } // Ensure the variables are in the symbol database // Also ensure the variables are pointers // Only keep variables which are pointers const Variable *var = variable->variable(); if (!var || !var->isPointer() || var->isArray()) { variable = 0; } if (variable2) { var = variable2->variable(); if (!var || !var->isPointer() || var->isArray()) { variable2 = 0; } } // If there are no pointer variable at this point, there is // no need to continue if (variable == 0 && variable2 == 0) { continue; } // Jump to the next sizeof token in the function and in the parameter // This is to allow generic operations with sizeof for (; tokVar && tokVar->str() != ")" && tokVar->str() != "," && tokVar->str() != "sizeof"; tokVar = tokVar->next()) {} // Now check for the sizeof usage. Once here, everything using sizeof(varid) or sizeof(&varid) // looks suspicious // Do it for first variable if (variable && (Token::Match(tokVar, "sizeof ( &| %varid% )", variable->varId()) || Token::Match(tokVar, "sizeof &| %varid%", variable->varId()))) { sizeofForPointerError(variable, variable->str()); } else if (variable2 && (Token::Match(tokVar, "sizeof ( &| %varid% )", variable2->varId()) || Token::Match(tokVar, "sizeof &| %varid%", variable2->varId()))) { sizeofForPointerError(variable2, variable2->str()); } } } } void CheckOther::sizeofForPointerError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "pointerSize", "Size of pointer '" + varname + "' used instead of size of its data.\n" "Size of pointer '" + varname + "' used instead of size of its data. " "This is likely to lead to a buffer overflow. You probably intend to " "write 'sizeof(*" + varname + ")'.", true); } //--------------------------------------------------------------------------- // Detect redundant assignments: x = 0; x = 4; //--------------------------------------------------------------------------- static bool nonLocal(const Variable* var) { return !var || (!var->isLocal() && !var->isArgument()) || var->isStatic() || var->isReference(); } static void eraseNotLocalArg(std::map& container, const SymbolDatabase* symbolDatabase) { for (std::map::iterator i = container.begin(); i != container.end();) { const Variable* var = symbolDatabase->getVariableFromVarId(i->first); if (!var || nonLocal(var)) { container.erase(i++); if (i == container.end()) break; } else ++i; } } void CheckOther::checkRedundantAssignment() { if (!_settings->isEnabled("performance")) return; const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase(); for (std::list::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { if (!scope->isExecutable()) continue; std::map varAssignments; std::map memAssignments; const Token* writtenArgumentsEnd = 0; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok == writtenArgumentsEnd) writtenArgumentsEnd = 0; if (tok->str() == "{" && tok->strAt(-1) != "{" && tok->strAt(-1) != "=" && tok->strAt(-4) != "case" && tok->strAt(-3) != "default") { // conditional or non-executable inner scope: Skip it and reset status tok = tok->link(); varAssignments.clear(); memAssignments.clear(); } else if (Token::Match(tok, "for|if|while (")) { tok = tok->linkAt(1); } else if (Token::Match(tok, "break|return|continue|throw|goto")) { varAssignments.clear(); memAssignments.clear(); } else if (tok->type() == Token::eVariable) { std::map::iterator it = varAssignments.find(tok->varId()); if (tok->next()->isAssignmentOp() && Token::Match(tok->previous(), "[;{}]")) { // Assignment if (it != varAssignments.end()) { bool error = true; // Ensure that variable is not used on right side for (const Token* tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { if (tok2->str() == ";") break; else if (tok2->varId() == tok->varId()) error = false; else if (Token::Match(tok2, "%var% (") && nonLocal(tok->variable())) { // Called function might use the variable const Function* func = symbolDatabase->findFunction(tok2); const Variable* var = tok->variable(); if (!var || var->isGlobal() || var->isReference() || ((!func || func->nestedIn) && tok2->strAt(-1) != ".")) // Global variable, or member function error = false; } } if (error) { if (scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok)) redundantAssignmentInSwitchError(it->second, tok, tok->str()); else redundantAssignmentError(it->second, tok, tok->str(), nonLocal(it->second->variable())); // Inconclusive for non-local variables } it->second = tok; } if (Token::simpleMatch(tok->tokAt(2), "0 ;")) varAssignments.erase(tok->varId()); else varAssignments[tok->varId()] = tok; memAssignments.erase(tok->varId()); } else if (tok->next()->type() == Token::eIncDecOp || (tok->previous()->type() == Token::eIncDecOp && !Token::Match(tok->next(), ".|[|("))) { // Variable incremented/decremented varAssignments[tok->varId()] = tok; memAssignments.erase(tok->varId()); } else if (!Token::simpleMatch(tok->tokAt(-2), "sizeof (")) { // Other usage of variable if (it != varAssignments.end()) varAssignments.erase(it); if (!writtenArgumentsEnd) // Indicates that we are in the first argument of strcpy/memcpy/... function memAssignments.erase(tok->varId()); } } else if (Token::Match(tok, "%var% (")) { // Function call. Global variables might be used. Reset their status bool memfunc = Token::Match(tok, "memcpy|memmove|memset|strcpy|strncpy|sprintf|snprintf|strcat|strncat|wcscpy|wcsncpy|swprintf|wcscat|wcsncat"); if (memfunc) { const Token* param1 = tok->tokAt(2); writtenArgumentsEnd = param1->next(); if (param1->varId() && param1->strAt(1) == "," && !Token::Match(tok, "strcat|strncat|wcscat|wcsncat")) { std::map::iterator it = memAssignments.find(param1->varId()); if (it == memAssignments.end()) memAssignments[param1->varId()] = tok; else { if (scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok)) redundantCopyInSwitchError(it->second, tok, param1->str()); else redundantCopyError(it->second, tok, param1->str()); } } } else if (scope->type == Scope::eSwitch) { // Avoid false positives if noreturn function is called in switch const Function* func = tok->function(); if (!func || !func->hasBody) { varAssignments.clear(); memAssignments.clear(); continue; } const Token* funcEnd = func->functionScope->classEnd; bool noreturn; if (!_tokenizer->IsScopeNoReturn(funcEnd, &noreturn) && !noreturn) { eraseNotLocalArg(varAssignments, symbolDatabase); eraseNotLocalArg(memAssignments, symbolDatabase); } else { varAssignments.clear(); memAssignments.clear(); } } else { // Noreturn functions outside switch don't cause problems eraseNotLocalArg(varAssignments, symbolDatabase); eraseNotLocalArg(memAssignments, symbolDatabase); } } } } } void CheckOther::redundantCopyError(const Token *tok1, const Token* tok2, const std::string& var) { std::list callstack; callstack.push_back(tok1); callstack.push_back(tok2); reportError(callstack, Severity::performance, "redundantCopy", "Buffer '" + var + "' is being written before its old content has been used."); } void CheckOther::redundantCopyInSwitchError(const Token *tok1, const Token* tok2, const std::string &var) { std::list callstack; callstack.push_back(tok1); callstack.push_back(tok2); reportError(callstack, Severity::warning, "redundantCopyInSwitch", "Buffer '" + var + "' is being written before its old content has been used. 'break;' missing?"); } void CheckOther::redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive) { std::list callstack; callstack.push_back(tok1); callstack.push_back(tok2); if (inconclusive) reportError(callstack, Severity::performance, "redundantAssignment", "Variable '" + var + "' is reassigned a value before the old one has been used if variable is no semaphore variable.\n" "Variable '" + var + "' is reassigned a value before the old one has been used. Make sure that this variable is not used like a semaphore in a threading environment before simplifying this code.", true); else reportError(callstack, Severity::performance, "redundantAssignment", "Variable '" + var + "' is reassigned a value before the old one has been used."); } void CheckOther::redundantAssignmentInSwitchError(const Token *tok1, const Token* tok2, const std::string &var) { std::list callstack; callstack.push_back(tok1); callstack.push_back(tok2); reportError(callstack, Severity::warning, "redundantAssignInSwitch", "Variable '" + var + "' is reassigned a value before the old one has been used. 'break;' missing?"); } //--------------------------------------------------------------------------- // switch (x) // { // case 2: // y = a; // <- this assignment is redundant // case 3: // y = b; // <- case 2 falls through and sets y twice // } //--------------------------------------------------------------------------- static inline bool isFunctionOrBreakPattern(const Token *tok) { if (Token::Match(tok, "%var% (") || Token::Match(tok, "break|continue|return|exit|goto|throw")) return true; return false; } void CheckOther::checkRedundantAssignmentInSwitch() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); // Find the beginning of a switch. E.g.: // switch (var) { ... for (std::list::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) { if (i->type != Scope::eSwitch || !i->classStart) continue; // Check the contents of the switch statement std::map varsWithBitsSet; std::map bitOperations; for (const Token *tok2 = i->classStart->next(); tok2 != i->classEnd; 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) { varsWithBitsSet.erase(tok3->varId()); bitOperations.erase(tok3->varId()); } else if (isFunctionOrBreakPattern(tok3)) { varsWithBitsSet.clear(); bitOperations.clear(); } } tok2 = endOfConditional; } } // 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) { varsWithBitsSet.erase(tok2->varId()); bitOperations.erase(tok2->varId()); } // Bitwise operation. Report an error if it's performed twice before a break. E.g.: // case 3: b |= 1; // <== redundant // case 4: b |= 1; else if (Token::Match(tok2->previous(), ";|{|}|: %var% = %var% %or%|& %num% ;") && tok2->varId() != 0 && tok2->varId() == tok2->tokAt(2)->varId()) { std::string bitOp = tok2->strAt(3) + tok2->strAt(4); std::map::iterator i2 = varsWithBitsSet.find(tok2->varId()); // This variable has not had a bit operation performed on it yet, so just make a note of it if (i2 == varsWithBitsSet.end()) { varsWithBitsSet[tok2->varId()] = tok2; bitOperations[tok2->varId()] = bitOp; } // The same bit operation has been performed on the same variable twice, so report an error else if (bitOperations[tok2->varId()] == bitOp) redundantBitwiseOperationInSwitchError(i2->second, i2->second->str()); // A different bit operation was performed on the variable, so clear it else { varsWithBitsSet.erase(tok2->varId()); bitOperations.erase(tok2->varId()); } } // 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 && tok2->strAt(1) != "|" && tok2->strAt(1) != "&") { varsWithBitsSet.erase(tok2->varId()); bitOperations.erase(tok2->varId()); } // Reset our record of assignments if there is a break or function call. E.g.: // case 3: b = 1; break; if (isFunctionOrBreakPattern(tok2)) { varsWithBitsSet.clear(); bitOperations.clear(); } } } } void CheckOther::redundantBitwiseOperationInSwitchError(const Token *tok, const std::string &varname) { reportError(tok, Severity::warning, "redundantBitwiseOperationInSwitch", "Redundant bitwise operation on '" + varname + "' in 'switch' statement. 'break;' missing?"); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkSwitchCaseFallThrough() { if (!(_settings->isEnabled("style") && _settings->experimental)) return; const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase(); for (std::list::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) { if (i->type != Scope::eSwitch || !i->classStart) // Find the beginning of a switch continue; // 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 = i->classStart; tok2 != i->classEnd; 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::simpleMatch(tok2, "switch (")) { // skip over nested switch, we'll come to that soon tok2 = tok2->next()->link()->next()->link(); } else if (Token::Match(tok2, "break|continue|return|exit|goto|throw")) { 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; } } } } void CheckOther::switchCaseFallThrough(const Token *tok) { reportError(tok, Severity::style, "switchCaseFallThrough", "Switch falls through case without comment. 'break;' missing?"); } //--------------------------------------------------------------------------- // Check for statements like case A||B: in switch() //--------------------------------------------------------------------------- void CheckOther::checkSuspiciousCaseInSwitch() { if (!_settings->inconclusive || !_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (std::list::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) { if (i->type != Scope::eSwitch) continue; for (const Token* tok = i->classStart->next(); tok != i->classEnd; tok = tok->next()) { if (tok->str() == "case") { const Token* end = 0; for (const Token* tok2 = tok->next(); tok2; tok2 = tok2->next()) { if (tok2->str() == ":") { end = tok2; break; } if (Token::Match(tok2, "[?;}{]")) { break; } } if (end) { const Token* finding = Token::findmatch(tok->next(), "&&|%oror%", end); if (finding) suspiciousCaseInSwitchError(tok, finding->str()); } } } } } void CheckOther::suspiciousCaseInSwitchError(const Token* tok, const std::string& operatorString) { reportError(tok, Severity::warning, "suspiciousCase", "Found suspicious case label in switch(). Operator '" + operatorString + "' probably doesn't work as intended.\n" "Using an operator like '" + operatorString + "' in a case label is suspicious. Did you intend to use a bitwise operator, multiple case labels or if/else instead?", true); } //--------------------------------------------------------------------------- // if (x == 1) // x == 0; // <- suspicious equality comparison. //--------------------------------------------------------------------------- void CheckOther::checkSuspiciousEqualityComparison() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "for (")) { const Token* const openParen = tok->next(); const Token* const closeParen = tok->linkAt(1); // Search for any suspicious equality comparison in the initialization // or increment-decrement parts of the for() loop. // For example: // for (i == 2; i < 10; i++) // or // for (i = 0; i < 10; i == a) const Token* tok2 = Token::findmatch(openParen, "[;(] %var% == %any% [;)]", closeParen); if (tok2 && (tok2 == openParen || tok2->tokAt(4) == closeParen)) { suspiciousEqualityComparisonError(tok2->tokAt(2)); } // Equality comparisons with 0 are simplified to negation. For instance, // (x == 0) is simplified to (!x), so also check for suspicious negation // in the initialization or increment-decrement parts of the for() loop. // For example: // for (!i; i < 10; i++) const Token* tok3 = Token::findmatch(openParen, "[;(] ! %var% [;)]", closeParen); if (tok3 && (tok3 == openParen || tok3->tokAt(3) == closeParen)) { suspiciousEqualityComparisonError(tok3->tokAt(2)); } // Skip over for() loop conditions because "for (;running==1;)" // is a bit strange, but not necessarily incorrect. tok = closeParen; } if (Token::Match(tok, "[;{}] *| %var% == %any% ;")) { // Exclude compound statements surrounded by parentheses, such as // printf("%i\n", ({x==0;})); // because they may appear as an expression in GNU C/C++. // See http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html const Token* afterStatement = tok->strAt(1) == "*" ? tok->tokAt(6) : tok->tokAt(5); if (!Token::simpleMatch(afterStatement, "} )")) suspiciousEqualityComparisonError(tok->next()); } } } void CheckOther::suspiciousEqualityComparisonError(const Token* tok) { reportError(tok, Severity::warning, "suspiciousEqualityComparison", "Found suspicious equality comparison. Did you intend to assign a value instead?", true); } //--------------------------------------------------------------------------- // int x = 1; // x = x; // <- redundant assignment to self // // int y = y; // <- redundant initialization to self //--------------------------------------------------------------------------- static bool isTypeWithoutSideEffects(const Tokenizer *tokenizer, const Variable* var) { return ((var && (!var->isClass() || var->isPointer() || Token::simpleMatch(var->typeStartToken(), "std ::"))) || !tokenizer->isCPP()); } static inline const Token *findSelfAssignPattern(const Token *start) { return Token::findmatch(start, "%var% = %var% ;|=|)"); } void CheckOther::checkSelfAssignment() { if (!_settings->isEnabled("style")) return; const Token *tok = findSelfAssignPattern(_tokenizer->tokens()); while (tok) { if (Token::Match(tok->previous(), "[;{}.]") && tok->varId() && tok->varId() == tok->tokAt(2)->varId() && isTypeWithoutSideEffects(_tokenizer, tok->variable())) { 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 = findSelfAssignPattern(tok->next()); } } 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 //--------------------------------------------------------------------------- static inline const Token *findAssertPattern(const Token *start) { return Token::findmatch(start, "assert ( %any%"); } void CheckOther::checkAssignmentInAssert() { if (!_settings->isEnabled("style")) return; const Token *tok = findAssertPattern(_tokenizer->tokens()); const Token *endTok = tok ? tok->next()->link() : NULL; while (tok && endTok) { for (tok = tok->tokAt(2); tok != endTok; tok = tok->next()) { if (tok->isName() && (tok->next()->isAssignmentOp() || tok->next()->type() == Token::eIncDecOp)) assignmentInAssertError(tok, tok->str()); else if (Token::Match(tok, "--|++ %var%")) assignmentInAssertError(tok, tok->strAt(1)); } tok = findAssertPattern(endTok->next()); 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 executed. 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. //--------------------------------------------------------------------------- enum Position { First, Second, NA }; enum Relation { Equal, NotEqual, Less, LessEqual, More, MoreEqual }; struct Condition { Position position; const char *opTokStr; }; static std::string invertOperatorForOperandSwap(std::string s) { for (std::string::size_type i = 0; i < s.length(); i++) { if (s[i] == '>') s[i] = '<'; else if (s[i] == '<') s[i] = '>'; } return s; } static bool analyzeLogicOperatorCondition(const Condition& c1, const Condition& c2, bool inv1, bool inv2, bool varFirst1, bool varFirst2, const std::string& firstConstant, const std::string& secondConstant, const Token* op1Tok, const Token* op3Tok, Relation relation) { if (!(c1.position == NA || (c1.position == First && varFirst1) || (c1.position == Second && !varFirst1))) return false; if (!(c2.position == NA || (c2.position == First && varFirst2) || (c2.position == Second && !varFirst2))) return false; if (!Token::Match(op1Tok, inv1?invertOperatorForOperandSwap(c1.opTokStr).c_str():c1.opTokStr)) return false; if (!Token::Match(op3Tok, inv2?invertOperatorForOperandSwap(c2.opTokStr).c_str():c2.opTokStr)) return false; return (relation == Equal && MathLib::isEqual(firstConstant, secondConstant)) || (relation == NotEqual && MathLib::isNotEqual(firstConstant, secondConstant)) || (relation == Less && MathLib::isLess(firstConstant, secondConstant)) || (relation == LessEqual && MathLib::isLessEqual(firstConstant, secondConstant)) || (relation == More && MathLib::isGreater(firstConstant, secondConstant)) || (relation == MoreEqual && MathLib::isGreaterEqual(firstConstant, secondConstant)); } void CheckOther::checkIncorrectLogicOperator() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t ii = 0; ii < functions; ++ii) { const Scope * scope = symbolDatabase->functionScopes[ii]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { // Find a pair of comparison expressions with or without parentheses // with a shared variable and constants and with a logical operator between them. // e.g. if (x != 3 || x != 4) const Token *term1Tok = NULL, *term2Tok = NULL; const Token *op1Tok = NULL, *op2Tok = NULL, *op3Tok = NULL, *nextTok = NULL; if (Token::Match(tok, "( %any% %comp% %any% ) &&|%oror%")) { term1Tok = tok->next(); op1Tok = tok->tokAt(2); op2Tok = tok->tokAt(5); } else if (Token::Match(tok, "%any% %comp% %any% &&|%oror%")) { term1Tok = tok; op1Tok = tok->next(); op2Tok = tok->tokAt(3); } if (op2Tok) { if (Token::Match(op2Tok->next(), "( %any% %comp% %any% ) %any%")) { term2Tok = op2Tok->tokAt(2); op3Tok = op2Tok->tokAt(3); nextTok = op2Tok->tokAt(6); } else if (Token::Match(op2Tok->next(), "%any% %comp% %any% %any%")) { term2Tok = op2Tok->next(); op3Tok = op2Tok->tokAt(2); nextTok = op2Tok->tokAt(4); } } if (nextTok) { // Find the common variable and the two different-valued constants std::string firstConstant, secondConstant; bool varFirst1, varFirst2; unsigned int varId; const Token *var1Tok = NULL, *var2Tok = NULL; if (Token::Match(term1Tok, "%var% %any% %num%")) { var1Tok = term1Tok; varId = var1Tok->varId(); if (!varId) { continue; } varFirst1 = true; firstConstant = term1Tok->strAt(2); } else if (Token::Match(term1Tok, "%num% %any% %var%")) { var1Tok = term1Tok->tokAt(2); varId = var1Tok->varId(); if (!varId) { continue; } varFirst1 = false; firstConstant = term1Tok->str(); } else { continue; } if (Token::Match(term2Tok, "%var% %any% %num%")) { var2Tok = term2Tok; varFirst2 = true; secondConstant = term2Tok->strAt(2); } else if (Token::Match(term2Tok, "%num% %any% %var%")) { var2Tok = term2Tok->tokAt(2); varFirst2 = false; secondConstant = term2Tok->str(); } else { continue; } if (varId != var2Tok->varId() || firstConstant.empty() || secondConstant.empty()) { continue; } enum LogicError { AlwaysFalse, AlwaysTrue, FirstTrue, FirstFalse, SecondTrue, SecondFalse }; static const struct LinkedConditions { const char *before; Condition c1; const char *op2TokStr; Condition c2; const char *after; Relation relation; LogicError error; } conditions[] = { { "!!&&", { NA, "!=" }, "%oror%", { NA, "!=" }, "!!&&", NotEqual, AlwaysTrue }, // (x != 1) || (x != 3) <- always true { 0, { NA, "==" }, "&&", { NA, "==" }, 0, NotEqual, AlwaysFalse }, // (x == 1) && (x == 3) <- always false { "!!&&", { First, ">" }, "%oror%", { First, "<" }, "!!&&", Less, AlwaysTrue }, // (x > 3) || (x < 10) <- always true { "!!&&", { First, ">=" }, "%oror%", { First, "<|<=" }, "!!&&", LessEqual, AlwaysTrue }, // (x >= 3) || (x < 10) <- always true { "!!&&", { First, ">" }, "%oror%", { First, "<=" }, "!!&&", LessEqual, AlwaysTrue }, // (x > 3) || (x <= 10) <- always true { 0, { First, "<" }, "&&", { First, ">" }, 0, LessEqual, AlwaysFalse }, // (x < 1) && (x > 3) <- always false { 0, { First, "<=" }, "&&", { First, ">|>=" }, 0, Less, AlwaysFalse }, // (x <= 1) && (x > 3) <- always false { 0, { First, "<" }, "&&", { First, ">=" }, 0, Less, AlwaysFalse }, // (x < 1) && (x >= 3) <- always false { 0, { First, ">" }, "&&", { NA, "==" }, 0, MoreEqual, AlwaysFalse }, // (x > 5) && (x == 1) <- always false { 0, { First, "<" }, "&&", { NA, "==" }, 0, LessEqual, AlwaysFalse }, // (x < 1) && (x == 3) <- always false { 0, { First, ">=" }, "&&", { NA, "==" }, 0, More, AlwaysFalse }, // (x >= 5) && (x == 1) <- always false { 0, { First, "<=" }, "&&", { NA, "==" }, 0, Less, AlwaysFalse }, // (x <= 1) && (x == 3) <- always false { "!!&&", { NA, "==" }, "%oror%", { First, ">" }, "!!&&", More, SecondTrue }, // (x == 4) || (x > 3) <- second expression always true { "!!&&", { NA, "==" }, "%oror%", { First, "<" }, "!!&&", Less, SecondTrue }, // (x == 4) || (x < 5) <- second expression always true { "!!&&", { NA, "==" }, "%oror%", { First, ">=" }, "!!&&", MoreEqual, SecondTrue }, // (x == 4) || (x >= 3) <- second expression always true { "!!&&", { NA, "==" }, "%oror%", { First, "<=" }, "!!&&", LessEqual, SecondTrue }, // (x == 4) || (x <= 5) <- second expression always true { "!!&&", { First, ">" }, "%oror%", { NA, "!=" }, "!!&&", MoreEqual, SecondTrue }, // (x > 5) || (x != 1) <- second expression always true { "!!&&", { First, "<" }, "%oror%", { NA, "!=" }, "!!&&", LessEqual, SecondTrue }, // (x < 1) || (x != 3) <- second expression always true { "!!&&", { First, ">=" }, "%oror%", { NA, "!=" }, "!!&&", More, SecondTrue }, // (x >= 5) || (x != 1) <- second expression always true { "!!&&", { First, "<=" }, "%oror%", { NA, "!=" }, "!!&&", Less, SecondTrue }, // (x <= 1) || (x != 3) <- second expression always true { 0, { First, ">" }, "&&", { NA, "!=" }, 0, MoreEqual, SecondTrue }, // (x > 5) && (x != 1) <- second expression always true { 0, { First, "<" }, "&&", { NA, "!=" }, 0, LessEqual, SecondTrue }, // (x < 1) && (x != 3) <- second expression always true { 0, { First, ">=" }, "&&", { NA, "!=" }, 0, More, SecondTrue }, // (x >= 5) && (x != 1) <- second expression always true { 0, { First, "<=" }, "&&", { NA, "!=" }, 0, Less, SecondTrue }, // (x <= 1) && (x != 3) <- second expression always true { "!!&&", { First, ">|>=" }, "%oror%", { First, ">|>=" }, "!!&&", LessEqual, SecondTrue }, // (x > 4) || (x > 5) <- second expression always true { "!!&&", { First, "<|<=" }, "%oror%", { First, "<|<=" }, "!!&&", MoreEqual, SecondTrue }, // (x < 5) || (x < 4) <- second expression always true { 0, { First, ">|>=" }, "&&", { First, ">|>=" }, 0, MoreEqual, SecondTrue }, // (x > 4) && (x > 5) <- second expression always true { 0, { First, "<|<=" }, "&&", { First, "<|<=" }, 0, MoreEqual, SecondTrue }, // (x < 5) && (x < 4) <- second expression always true { 0, { NA, "==" }, "&&", { NA, "!=" }, 0, NotEqual, SecondTrue }, // (x == 3) && (x != 4) <- second expression always true { "!!&&", { NA, "==" }, "%oror%", { NA, "!=" }, "!!&&", NotEqual, SecondTrue }, // (x == 3) || (x != 4) <- second expression always true { 0, { NA, "!=" }, "&&", { NA, "==" }, 0, Equal, AlwaysFalse }, // (x != 3) && (x == 3) <- expression always false { "!!&&", { NA, "!=" }, "%oror%", { NA, "==" }, "!!&&", Equal, AlwaysTrue }, // (x != 3) || (x == 3) <- expression always true }; for (unsigned int i = 0; i < (sizeof(conditions) / sizeof(conditions[0])); i++) { if (!Token::Match(op2Tok, conditions[i].op2TokStr)) continue; if (conditions[i].before != 0 && !Token::Match(tok->previous(), conditions[i].before)) continue; if (conditions[i].after != 0 && !Token::Match(nextTok, conditions[i].after)) continue; if (tok->previous()->isArithmeticalOp() || nextTok->isArithmeticalOp()) continue; std::string cond1str = var1Tok->str() + " " + (varFirst1?op1Tok->str():invertOperatorForOperandSwap(op1Tok->str())) + " " + firstConstant; std::string cond2str = var2Tok->str() + " " + (varFirst2?op3Tok->str():invertOperatorForOperandSwap(op3Tok->str())) + " " + secondConstant; // cond1 op cond2 bool error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, false, varFirst1, varFirst2, firstConstant, secondConstant, op1Tok, op3Tok, conditions[i].relation); // inv(cond1) op cond2 // invert first condition if (!error && conditions[i].c1.position != NA) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, false, !varFirst1, varFirst2, firstConstant, secondConstant, op1Tok, op3Tok, conditions[i].relation); // cond1 op inv(cond2) // invert second condition if (!error && conditions[i].c2.position != NA) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, true, varFirst1, !varFirst2, firstConstant, secondConstant, op1Tok, op3Tok, conditions[i].relation); // inv(cond1) op inv(cond2) // invert both conditions if (!error && conditions[i].c1.position != NA && conditions[i].c2.position != NA) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, true, !varFirst1, !varFirst2, firstConstant, secondConstant, op1Tok, op3Tok, conditions[i].relation); if (!error) std::swap(cond1str, cond2str); // cond2 op cond1 // swap conditions if (!error) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, false, varFirst2, varFirst1, secondConstant, firstConstant, op3Tok, op1Tok, conditions[i].relation); // cond2 op inv(cond1) // swap conditions; invert first condition if (!error && conditions[i].c1.position != NA) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, false, !varFirst2, varFirst1, secondConstant, firstConstant, op3Tok, op1Tok, conditions[i].relation); // inv(cond2) op cond1 // swap conditions; invert second condition if (!error && conditions[i].c2.position != NA) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, false, true, varFirst2, !varFirst1, secondConstant, firstConstant, op3Tok, op1Tok, conditions[i].relation); // inv(cond2) op inv(cond1) // swap conditions; invert both conditions if (!error && conditions[i].c1.position != NA && conditions[i].c2.position != NA) error = analyzeLogicOperatorCondition(conditions[i].c1, conditions[i].c2, true, true, !varFirst2, !varFirst1, secondConstant, firstConstant, op3Tok, op1Tok, conditions[i].relation); if (error) { if (conditions[i].error == AlwaysFalse || conditions[i].error == AlwaysTrue) { const std::string text = cond1str + " " + op2Tok->str() + " " + cond2str; incorrectLogicOperatorError(term1Tok, text, conditions[i].error == AlwaysTrue); } else { const std::string text = "If " + cond1str + ", the comparison " + cond2str + " is always " + ((conditions[i].error == SecondTrue || conditions[i].error == AlwaysTrue) ? "true" : "false") + "."; redundantConditionError(term1Tok, text); } break; } } } } } } void CheckOther::incorrectLogicOperatorError(const Token *tok, const std::string &condition, bool always) { if (always) reportError(tok, Severity::warning, "incorrectLogicOperator", "Logical disjunction always evaluates to true: " + condition + ".\n" "Logical disjunction always evaluates to true: " + condition + ". " "Are these conditions necessary? Did you intend to use && instead? Are the numbers correct? Are you comparing the correct variables?"); else reportError(tok, Severity::warning, "incorrectLogicOperator", "Logical conjunction always evaluates to false: " + condition + ".\n" "Logical conjunction always evaluates to false: " + condition + ". " "Are these conditions necessary? Did you intend to use || instead? Are the numbers correct? Are you comparing the correct variables?"); } void CheckOther::redundantConditionError(const Token *tok, const std::string &text) { reportError(tok, Severity::style, "redundantCondition", "Redundant condition: " + text); } //--------------------------------------------------------------------------- // 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|strtoll|strtoull|wcstol|wcstoul|wcstoll|wcstoull (")) continue; const std::string& funcname = tok->str(); tok = tok->tokAt(2); // Locate the third parameter of the function call.. for (int i = 0; i < 2 && tok; i++) tok = tok->nextArgument(); if (Token::Match(tok, "%num% )")) { const MathLib::bigint radix = MathLib::toLongNumber(tok->str()); if (!(radix == 0 || (radix >= 2 && radix <= 36))) { dangerousUsageStrtolError(tok, funcname); } } else 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|swprintf ( %var% ,")) varid = tok->tokAt(2)->varId(); else if (Token::Match(tok, "sprintf|snprintf|swprintf ( %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" || tok->str() == "swprintf") { // Jump over second parameter for snprintf and swprintf tok2 = tok2->nextArgument(); if (!tok2) continue; } // is any source buffer overlapping the target buffer? do { if (Token::Match(tok2, "%varid% [,)]", varid)) { sprintfOverlappingDataError(tok2, tok2->str()); break; } } while (NULL != (tok2 = tok2->nextArgument())); } } void CheckOther::dangerousUsageStrtolError(const Token *tok, const std::string& funcname) { reportError(tok, Severity::error, "dangerousUsageStrtol", "Invalid radix in call to " + funcname + "(). It must be 0 or 2-36."); } void CheckOther::sprintfOverlappingDataError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "sprintfOverlappingData", "Undefined behavior: Variable '" + varname + "' is used as parameter and destination in s[n]printf().\n" "The variable '" + varname + "' is used both as a parameter and as 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.\""); } //--------------------------------------------------------------------------- // if (!x==3) <- Probably meant to be "x!=3" //--------------------------------------------------------------------------- static bool isBool(const Variable* var) { return(var && var->typeEndToken()->str() == "bool"); } static bool isNonBoolStdType(const Variable* var) { return(var && var->typeEndToken()->isStandardType() && var->typeEndToken()->str() != "bool"); } void CheckOther::checkComparisonOfBoolWithInt() { if (!_settings->isEnabled("style")) return; const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->next() && tok->next()->type() == Token::eComparisonOp && (!tok->previous() || !tok->previous()->isArithmeticalOp()) && (!tok->tokAt(3) || !tok->tokAt(3)->isArithmeticalOp())) { const Token* const right = tok->tokAt(2); if ((tok->varId() && right->isNumber()) || (tok->isNumber() && right->varId())) { // Comparing variable with number const Token* varTok = tok; const Token* numTok = right; if (tok->isNumber() && right->varId()) // num with var std::swap(varTok, numTok); if (isBool(varTok->variable()) && // 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(), tok->strAt(1) == "==" || tok->strAt(1) == "!="); } } else if (tok->isBoolean() && right->varId()) { // Comparing boolean constant with variable if (isNonBoolStdType(right->variable())) { // Variable has to be of non-boolean standard type comparisonOfBoolWithIntError(right, tok->str(), false); } else if (tok->strAt(1) != "==" && tok->strAt(1) != "!=") { comparisonOfBoolWithInvalidComparator(right, tok->str()); } } else if (tok->varId() && right->isBoolean()) { // Comparing variable with boolean constant if (isNonBoolStdType(tok->variable())) { // Variable has to be of non-boolean standard type comparisonOfBoolWithIntError(tok, right->str(), false); } else if (tok->strAt(1) != "==" && tok->strAt(1) != "!=") { comparisonOfBoolWithInvalidComparator(right, tok->str()); } } else if (tok->isNumber() && right->isBoolean()) { // number constant with boolean constant comparisonOfBoolWithIntError(tok, right->str(), false); } else if (tok->isBoolean() && right->isNumber()) { // number constant with boolean constant comparisonOfBoolWithIntError(tok, tok->str(), false); } else if (tok->varId() && right->varId()) { // Comparing two variables, one of them boolean, one of them integer const Variable* var1 = right->variable(); const Variable* var2 = tok->variable(); if (isBool(var1) && isNonBoolStdType(var2)) // Comparing boolean with non-bool standard type comparisonOfBoolWithIntError(tok, var1->name(), false); else if (isNonBoolStdType(var1) && isBool(var2)) // Comparing non-bool standard type with boolean comparisonOfBoolWithIntError(tok, var2->name(), false); } } } } } void CheckOther::comparisonOfBoolWithIntError(const Token *tok, const std::string &expression, bool n0o1) { if (n0o1) reportError(tok, Severity::warning, "comparisonOfBoolWithInt", "Comparison of a boolean with an integer that is neither 1 nor 0.\n" "The expression '" + expression + "' is of type 'bool' " "and it is compared against an integer value that is " "neither 1 nor 0."); else reportError(tok, Severity::warning, "comparisonOfBoolWithInt", "Comparison of a boolean with an integer.\n" "The expression '" + expression + "' is of type 'bool' " "and it is compared against an integer value."); } void CheckOther::comparisonOfBoolWithInvalidComparator(const Token *tok, const std::string &expression) { reportError(tok, Severity::warning, "comparisonOfBoolWithInvalidComparator", "Comparison of a boolean value using relational operator (<, >, <= or >=).\n" "The result of the expression '" + expression + "' is of type 'bool'. " "Comparing 'bool' value using relational (<, >, <= or >=)" " operator could cause unexpected results."); } //--------------------------------------------------------------------------- // Find consecutive return, break, continue, goto or throw statements. e.g.: // break; break; // Detect dead code, that follows such a statement. e.g.: // return(0); foo(); //--------------------------------------------------------------------------- void CheckOther::checkUnreachableCode() { if (!_settings->isEnabled("style")) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { const Token* secondBreak = 0; const Token* labelName = 0; if (tok->str() == "(") tok = tok->link(); else if (Token::Match(tok, "break|continue ;")) secondBreak = tok->tokAt(2); else if (Token::Match(tok, "[;{}:] return|throw")) { tok = tok->next(); // tok should point to return or throw for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) if (tok2->str() == ";") { secondBreak = tok2->next(); break; } } else if (Token::Match(tok, "goto %any% ;")) { secondBreak = tok->tokAt(3); labelName = tok->next(); } // Statements follow directly, no line between them. (#3383) // TODO: Try to find a better way to avoid false positives due to preprocessor configurations. bool inconclusive = secondBreak && (secondBreak->linenr()-1 > secondBreak->previous()->linenr()); if (secondBreak && (_settings->inconclusive || !inconclusive)) { if (Token::Match(secondBreak, "continue|goto|throw") || (secondBreak->str() == "return" && (tok->str() == "return" || secondBreak->strAt(1) == ";"))) { // return with value after statements like throw can be necessary to make a function compile duplicateBreakError(secondBreak, inconclusive); tok = Token::findmatch(secondBreak, "[}:]"); } else if (secondBreak->str() == "break") { // break inside switch as second break statement should not issue a warning if (tok->str() == "break") // If the previous was a break, too: Issue warning duplicateBreakError(secondBreak, inconclusive); else { if (tok->scope()->type != Scope::eSwitch) // Check, if the enclosing scope is a switch duplicateBreakError(secondBreak, inconclusive); } tok = Token::findmatch(secondBreak, "[}:]"); } else if (!Token::Match(secondBreak, "return|}|case|default") && secondBreak->strAt(1) != ":") { // TODO: No bailout for unconditional scopes // If the goto label is followed by a loop construct in which the label is defined it's quite likely // that the goto jump was intended to skip some code on the first loop iteration. bool labelInFollowingLoop = false; if (labelName && Token::Match(secondBreak, "while|do|for")) { const Token *scope = Token::findsimplematch(secondBreak, "{"); if (scope) { for (const Token *tokIter = scope; tokIter != scope->link() && tokIter; tokIter = tokIter->next()) { if (Token::Match(tokIter, "[;{}] %any% :") && labelName->str() == tokIter->strAt(1)) { labelInFollowingLoop = true; break; } } } } if (!labelInFollowingLoop) unreachableCodeError(secondBreak, inconclusive); tok = Token::findmatch(secondBreak, "[}:]"); } else tok = secondBreak; if (!tok) break; } } } void CheckOther::duplicateBreakError(const Token *tok, bool inconclusive) { reportError(tok, Severity::style, "duplicateBreak", "Consecutive return, break, continue, goto or throw statements are unnecessary.\n" "Consecutive return, break, continue, goto or throw statements are unnecessary. " "The second statement can never be executed, and so should be removed.", inconclusive); } void CheckOther::unreachableCodeError(const Token *tok, bool inconclusive) { reportError(tok, Severity::style, "unreachableCode", "Statements following return, break, continue, goto or throw will never be executed.", inconclusive); } //--------------------------------------------------------------------------- // Check for unsigned divisions //--------------------------------------------------------------------------- bool CheckOther::isUnsigned(const Variable* var) const { return(var && var->typeStartToken()->isUnsigned() && !var->isPointer() && !var->isArray() && _tokenizer->sizeOfType(var->typeStartToken()) >= _settings->sizeof_int); } bool CheckOther::isSigned(const Variable* var) const { return(var && !var->typeStartToken()->isUnsigned() && Token::Match(var->typeEndToken(), "int|char|short|long") && !var->isPointer() && !var->isArray()); } void CheckOther::checkUnsignedDivision() { bool style = _settings->isEnabled("style"); const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; const Token* ifTok = 0; // Check for "ivar / uvar" and "uvar / ivar" for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "[).]")) // Don't check members or casted variables continue; if (Token::Match(tok->next(), "%var% / %num%")) { if (tok->strAt(3)[0] == '-' && isUnsigned(tok->next()->variable())) { udivError(tok->next(), false); } } else if (Token::Match(tok->next(), "%num% / %var%")) { if (tok->strAt(1)[0] == '-' && isUnsigned(tok->tokAt(3)->variable())) { udivError(tok->next(), false); } } else if (Token::Match(tok->next(), "%var% / %var%") && _settings->inconclusive && style && !ifTok) { const Variable* var1 = tok->next()->variable(); const Variable* var2 = tok->tokAt(3)->variable(); if ((isUnsigned(var1) && isSigned(var2)) || (isUnsigned(var2) && isSigned(var1))) { udivError(tok->next(), true); } } else if (!ifTok && Token::simpleMatch(tok, "if (")) ifTok = tok->next()->link()->next()->link(); else if (ifTok == tok) ifTok = 0; } } } void CheckOther::udivError(const Token *tok, bool inconclusive) { if (inconclusive) reportError(tok, Severity::warning, "udivError", "Division with signed and unsigned operators. The result might be wrong.", true); else 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() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; 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(); for (unsigned int i = 1; i < symbolDatabase->getVariableListSize(); i++) { const Variable* var = symbolDatabase->getVariableFromVarId(i); if (!var || !var->isLocal() || (!var->isPointer() && !var->typeStartToken()->isStandardType() && !var->typeStartToken()->next()->isStandardType())) continue; bool forHead = false; // Don't check variables declared in header of a for loop for (const Token* tok = var->typeStartToken(); tok; tok = tok->previous()) { if (tok->str() == "(") { forHead = true; break; } else if (tok->str() == "{" || tok->str() == ";" || tok->str() == "}") break; } if (forHead) continue; const Token* tok = var->nameToken()->next(); if (Token::Match(tok, "; %varid% = %any% ;", var->varId())) { tok = tok->tokAt(3); if (!tok->isNumber() && tok->type() != Token::eString && tok->type() != Token::eChar && !tok->isBoolean()) continue; } else if ((tok->str() == "=" || tok->str() == "(") && ((!tok->next()->isNumber() && tok->next()->type() != Token::eString && tok->next()->type() != Token::eChar && !tok->next()->isBoolean()) || tok->strAt(2) != ";")) continue; lookupVar(tok, var); } } void CheckOther::lookupVar(const Token *tok, const Variable* var) { // 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 -> reducible bool used2 = false; // used in more sub-scopes -> not reducible 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, "%varid%", tok->link(), var->varId())) { 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::Match(tok, "& %varid%", var->varId())) { return; } else if (tok->varId() == var->varId()) { if (indentlevel == 0) return; if (tok->strAt(-1) == "=" && (var->isArray() || var->isPointer())) // Create a copy of array/pointer. Bailout, because the memory it points to might be necessary in outer scope return; used1 = true; if (for_or_while && tok->strAt(1) != "=") 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 (tok->strAt(1) == "(" && 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(var->nameToken(), var->name()); } 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: Be careful " "when fixing this message, 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") || _tokenizer->isC()) return; const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase(); for (unsigned int i = 1; i < symbolDatabase->getVariableListSize(); i++) { const Variable* var = symbolDatabase->getVariableFromVarId(i); if (!var || !var->isArgument() || !var->isClass() || !var->isConst() || var->isPointer() || var->isArray() || var->isReference()) continue; const Token* const tok = var->typeStartToken(); // 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, "std :: string|wstring")) { passedByValueError(tok, var->name()); } else if (Token::Match(tok, "std :: %type% <") && !Token::simpleMatch(tok->linkAt(3), "> ::")) { passedByValueError(tok, var->name()); } else if (var->type() || symbolDatabase->isClassOrStruct(tok->str())) { // Check if type is a struct or class. passedByValueError(tok, var->name()); } } } 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 by value. It could be passed " "as a (const) reference which is usually faster and recommended in C++."); } //--------------------------------------------------------------------------- // Check usage of char variables.. //--------------------------------------------------------------------------- static bool isChar(const Variable* var) { return(var && !var->isPointer() && !var->isArray() && var->typeStartToken()->str() == "char"); } static bool isSignedChar(const Variable* var) { return(isChar(var) && !var->typeStartToken()->isUnsigned()); } void CheckOther::checkCharVariable() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { if ((tok->str() != ".") && Token::Match(tok->next(), "%var% [ %var% ]")) { const Variable* arrayvar = tok->next()->variable(); const Variable* indexvar = tok->tokAt(3)->variable(); const MathLib::bigint arraysize = (arrayvar && arrayvar->isArray()) ? arrayvar->dimension(0U) : 0; if (isSignedChar(indexvar) && arraysize > 0x80) charArrayIndexError(tok->next()); } else if (Token::Match(tok, "[;{}] %var% = %any% [&^|] %any% ;")) { // is a char variable used in the calculation? if (!isSignedChar(tok->tokAt(3)->variable()) && !isSignedChar(tok->tokAt(5)->variable())) continue; // it's ok with a bitwise and where the other operand is 0xff or less.. if (tok->strAt(4) == "&") { if (tok->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok->strAt(3))) continue; if (tok->tokAt(5)->isNumber() && MathLib::isGreater("0x100", tok->strAt(5))) continue; } // is the result stored in a short|int|long? const Variable *var = tok->next()->variable(); if (var && Token::Match(var->typeStartToken(), "short|int|long") && !var->isPointer() && !var->isArray()) charBitOpError(tok->tokAt(4)); // This is an error.. } else if (Token::Match(tok, "[;{}] %var% = %any% [&^|] ( * %var% ) ;")) { const Variable* var = tok->tokAt(7)->variable(); if (!var || !var->isPointer() || var->typeStartToken()->str() != "char" || var->typeStartToken()->isUnsigned()) continue; // it's ok with a bitwise and where the other operand is 0xff or less.. if (tok->strAt(4) == "&" && tok->tokAt(3)->isNumber() && MathLib::isGreater("0x100", tok->strAt(3))) continue; // is the result stored in a short|int|long? var = tok->next()->variable(); if (var && Token::Match(var->typeStartToken(), "short|int|long") && !var->isPointer() && !var->isArray()) charBitOpError(tok->tokAt(4)); // This is an error.. } } } } void CheckOther::charArrayIndexError(const Token *tok) { reportError(tok, Severity::warning, "charArrayIndex", "Signed 'char' type used as array index.\n" "Signed 'char' type used as array index. If the value " "can be greater than 127 there will be a buffer underflow " "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() { const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "[=(] %str% + %any%")) { // char constant.. if (tok->tokAt(3)->type() == Token::eChar) strPlusCharError(tok->next()); // char variable.. if (isChar(tok->tokAt(3)->variable())) strPlusCharError(tok->next()); } } } } void CheckOther::strPlusCharError(const Token *tok) { reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic. A value of type 'char' is added to a string literal."); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- 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() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->varId()) continue; if (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 interval [-1,+1], but not beyond else if (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 (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 (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 (Token::Match(tok, "fmod ( %any%")) { const Token* nextArg = tok->tokAt(2)->nextArgument(); if (nextArg && nextArg->isNumber() && MathLib::isNullValue(nextArg->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->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 values " + 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->strAt(2)); } } } void CheckOther::cctypefunctionCallError(const Token *tok, const std::string &functionName, const std::string &value) { reportError(tok, Severity::error, "wrongcctypecall", "Passing value " + value + " to " + functionName + "() causes undefined behavior which may lead to a crash."); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkMisusedScopedObject() { // Skip this check for .c files if (_tokenizer->isC()) { return; } const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "[;{}] %var% (") && Token::simpleMatch(tok->linkAt(2), ") ;") && symbolDatabase->isClassOrStruct(tok->next()->str()) && !tok->next()->function()) { 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 is destroyed immediately."); } //------------------------------------------------------------------------------- // Comparing functions which are returning value of type bool //------------------------------------------------------------------------------- void CheckOther::checkComparisonOfFuncReturningBool() { if (!_settings->isEnabled("style")) return; if (!_tokenizer->isCPP()) return; const SymbolDatabase * const symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->type() != Token::eComparisonOp || tok->str() == "==" || tok->str() == "!=") continue; const Token *first_token; bool first_token_func_of_type_bool = false; if (Token::simpleMatch(tok->previous(), ")")) { first_token = tok->previous()->link()->previous(); } else { first_token = tok->previous(); } if (Token::Match(first_token, "%var% (") && !Token::Match(first_token->previous(), "::|.")) { const Function* func = first_token->function(); if (func && func->tokenDef && func->tokenDef->strAt(-1) == "bool") { first_token_func_of_type_bool = true; } } Token *second_token = tok->next(); bool second_token_func_of_type_bool = false; while (second_token->str()=="!") { second_token = second_token->next(); } if (Token::Match(second_token, "%var% (") && !Token::Match(second_token->previous(), "::|.")) { const Function* func = second_token->function(); if (func && func->tokenDef && func->tokenDef->strAt(-1) == "bool") { second_token_func_of_type_bool = true; } } if ((first_token_func_of_type_bool == true) && (second_token_func_of_type_bool == true)) { comparisonOfTwoFuncsReturningBoolError(first_token->next(), first_token->str(), second_token->str()); } else if (first_token_func_of_type_bool == true) { comparisonOfFuncReturningBoolError(first_token->next(), first_token->str()); } else if (second_token_func_of_type_bool == true) { comparisonOfFuncReturningBoolError(second_token->previous(), second_token->str()); } } } } void CheckOther::comparisonOfFuncReturningBoolError(const Token *tok, const std::string &expression) { reportError(tok, Severity::style, "comparisonOfFuncReturningBoolError", "Comparison of a function returning boolean value using relational (<, >, <= or >=) operator.\n" "The return type of function '" + expression + "' is 'bool' " "and result is of type 'bool'. Comparing 'bool' value using relational (<, >, <= or >=)" " operator could cause unexpected results."); } void CheckOther::comparisonOfTwoFuncsReturningBoolError(const Token *tok, const std::string &expression1, const std::string &expression2) { reportError(tok, Severity::style, "comparisonOfTwoFuncsReturningBoolError", "Comparison of two functions returning boolean value using relational (<, >, <= or >=) operator.\n" "The return type of function '" + expression1 + "' and function '" + expression2 + "' is 'bool' " "and result is of type 'bool'. Comparing 'bool' value using relational (<, >, <= or >=)" " operator could cause unexpected results."); } //------------------------------------------------------------------------------- // Comparison of bool with bool //------------------------------------------------------------------------------- void CheckOther::checkComparisonOfBoolWithBool() { // FIXME: This checking is "experimental" because of the false positives // when self checking lib/tokenize.cpp (#2617) if (!_settings->experimental) return; if (!_settings->isEnabled("style")) return; if (!_tokenizer->isCPP()) return; const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->type() != Token::eComparisonOp || tok->str() == "==" || tok->str() == "!=") continue; bool first_token_bool = false; bool second_token_bool = false; const Token *first_token = tok->previous(); if (first_token->varId()) { if (isBool(first_token->variable())) { first_token_bool = true; } } const Token *second_token = tok->next(); if (second_token->varId()) { if (isBool(second_token->variable())) { second_token_bool = true; } } if ((first_token_bool == true) && (second_token_bool == true)) { comparisonOfBoolWithBoolError(first_token->next(), first_token->str()); } } } } void CheckOther::comparisonOfBoolWithBoolError(const Token *tok, const std::string &expression) { reportError(tok, Severity::style, "comparisonOfBoolWithBoolError", "Comparison of a variable having boolean value using relational (<, >, <= or >=) operator.\n" "The variable '" + expression + "' is of type 'bool' " "and comparing 'bool' value using relational (<, >, <= or >=)" " operator could cause unexpected results."); } //--------------------------------------------------------------------------- //--------------------------------------------------------------------------- void CheckOther::checkIncorrectStringCompare() { if (!_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { // skip "assert(str && ..)" and "assert(.. && str)" if (Token::Match(tok, "%var% (") && (Token::Match(tok->tokAt(2), "%str% &&") || Token::Match(tok->next()->link()->tokAt(-2), "&& %str% )")) && (tok->str().find("assert")+6U==tok->str().size() || tok->str().find("ASSERT")+6U==tok->str().size())) tok = tok->next()->link(); if (Token::Match(tok, ". substr ( %any% , %num% ) ==|!= %str%")) { MathLib::bigint clen = MathLib::toLongNumber(tok->strAt(5)); std::size_t slen = Token::getStrLength(tok->tokAt(8)); if (clen != (int)slen) { incorrectStringCompareError(tok->next(), "substr", tok->strAt(8)); } } else if (Token::Match(tok, "%str% ==|!= %var% . substr ( %any% , %num% )")) { MathLib::bigint clen = MathLib::toLongNumber(tok->strAt(8)); std::size_t slen = Token::getStrLength(tok); if (clen != (int)slen) { incorrectStringCompareError(tok->next(), "substr", tok->str()); } } else if (Token::Match(tok, "&&|%oror%|( %str% &&|%oror%|)") && !Token::Match(tok, "( %str% )")) { incorrectStringBooleanError(tok->next(), tok->strAt(1)); } else if (Token::Match(tok, "if|while ( %str% )")) { incorrectStringBooleanError(tok->tokAt(2), tok->strAt(2)); } } } } void CheckOther::incorrectStringCompareError(const Token *tok, const std::string& func, const std::string &string) { reportError(tok, Severity::warning, "incorrectStringCompare", "String literal " + string + " doesn't match length argument for " + func + "()."); } void CheckOther::incorrectStringBooleanError(const Token *tok, const std::string& string) { reportError(tok, Severity::warning, "incorrectStringBooleanError", "Conversion of string literal " + string + " to bool always evaluates to true."); } //----------------------------------------------------------------------------- // check for duplicate expressions in if statements // if (a) { } else if (a) { } //----------------------------------------------------------------------------- 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 (tok->type() == Token::eIncDecOp) 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(); for (std::list::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { const Token* const tok = scope->classDef; // only check if statements if (scope->type != Scope::eIf || !tok) continue; std::map expressionMap; // get the expression from the token stream std::string expression = tok->tokAt(2)->stringifyList(tok->next()->link()); // save the expression and its location expressionMap.insert(std::make_pair(expression, tok)); // find the next else if (...) statement const Token *tok1 = scope->classEnd; // check all the else if (...) statements while ((Token::simpleMatch(tok1, "} else if (") && Token::simpleMatch(tok1->linkAt(3), ") {")) || (Token::simpleMatch(tok1, "} else { if (") && Token::simpleMatch(tok1->linkAt(4), ") {"))) { int conditionIndex=(tok1->strAt(3)=="(") ? 3 : 4; // get the expression from the token stream expression = tok1->tokAt(conditionIndex+1)->stringifyList(tok1->linkAt(conditionIndex)); // 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(conditionIndex+1), tok1->linkAt(conditionIndex)->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(conditionIndex)->next()->link(); } } } 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", "Duplicate conditions in 'if' and related 'else if'.\n" "Duplicate conditions in 'if' and related 'else if'. This 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; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); std::list::const_iterator scope; for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { if (scope->type != Scope::eIf && scope->type != Scope::eElseIf) continue; // check all the code in the function for if (..) else if (Token::simpleMatch(scope->classEnd, "} else {")) { // save if branch code std::string branch1 = scope->classStart->next()->stringifyList(scope->classEnd); // save else branch code std::string branch2 = scope->classEnd->tokAt(3)->stringifyList(scope->classEnd->linkAt(2)); // check for duplicates if (branch1 == branch2) duplicateBranchError(scope->classDef, scope->classEnd->next()); } } } void CheckOther::duplicateBranchError(const Token *tok1, const Token *tok2) { std::list toks; toks.push_back(tok2); toks.push_back(tok1); reportError(toks, Severity::style, "duplicateBranch", "Found duplicate branches for 'if' and 'else'.\n" "Finding the same code in an 'if' and related '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."); } //----------------------------------------------------------------------------- // Check for a free() of an invalid address // char* p = malloc(100); // free(p + 10); //----------------------------------------------------------------------------- void CheckOther::checkInvalidFree() { std::map allocatedVariables; for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Keep track of which variables were assigned addresses to newly-allocated memory if (Token::Match(tok, "%var% = malloc|g_malloc|new")) { allocatedVariables.insert(std::make_pair(tok->varId(), false)); } // If a previously-allocated pointer is incremented or decremented, any subsequent // free involving pointer arithmetic may or may not be invalid, so we should only // report an inconclusive result. else if (Token::Match(tok, "%var% = %var% +|-") && tok->varId() == tok->tokAt(2)->varId() && allocatedVariables.find(tok->varId()) != allocatedVariables.end()) { if (_settings->inconclusive) allocatedVariables[tok->varId()] = true; else allocatedVariables.erase(tok->varId()); } // If a previously-allocated pointer is assigned a completely new value, // we can't know if any subsequent free() on that pointer is valid or not. else if (Token::Match(tok, "%var% = ")) { allocatedVariables.erase(tok->varId()); } // If a variable that was previously assigned a newly-allocated memory location is // added or subtracted from when used to free the memory, report an error. else if (Token::Match(tok, "free|g_free|delete ( %any% +|- %any%") || Token::Match(tok, "delete [ ] ( %any% +|- %any%") || Token::Match(tok, "delete %any% +|- %any%")) { const int varIdx = tok->strAt(1) == "(" ? 2 : tok->strAt(3) == "(" ? 4 : 1; const unsigned int var1 = tok->tokAt(varIdx)->varId(); const unsigned int var2 = tok->tokAt(varIdx + 2)->varId(); const std::map::iterator alloc1 = allocatedVariables.find(var1); const std::map::iterator alloc2 = allocatedVariables.find(var2); if (alloc1 != allocatedVariables.end()) { invalidFreeError(tok, alloc1->second); } else if (alloc2 != allocatedVariables.end()) { invalidFreeError(tok, alloc2->second); } } // If the previously-allocated variable is passed in to another function // as a parameter, it might be modified, so we shouldn't report an error // if it is later used to free memory else if (Token::Match(tok, "%var% (")) { const Token* tok2 = Token::findmatch(tok->tokAt(1), "%var%", tok->linkAt(1)); while (tok2 != NULL) { allocatedVariables.erase(tok2->varId()); tok2 = Token::findmatch(tok2->next(), "%var%", tok->linkAt(1)); } } } } void CheckOther::invalidFreeError(const Token *tok, bool inconclusive) { reportError(tok, Severity::error, "invalidFree", "Invalid memory address freed.", inconclusive); } //----------------------------------------------------------------------------- // Check for double free // free(p); free(p); //----------------------------------------------------------------------------- void CheckOther::checkDoubleFree() { std::set freedVariables; std::set closeDirVariables; for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) { // Keep track of any variables passed to "free()", "g_free()" or "closedir()", // and report an error if the same variable is passed twice. if (Token::Match(tok, "free|g_free|closedir ( %var% )")) { unsigned int var = tok->tokAt(2)->varId(); if (var) { if (Token::Match(tok, "free|g_free")) { if (freedVariables.find(var) != freedVariables.end()) doubleFreeError(tok, tok->strAt(2)); else freedVariables.insert(var); } else if (tok->str() == "closedir") { if (closeDirVariables.find(var) != closeDirVariables.end()) doubleCloseDirError(tok, tok->strAt(2)); else closeDirVariables.insert(var); } } } // Keep track of any variables operated on by "delete" or "delete[]" // and report an error if the same variable is delete'd twice. else if (Token::Match(tok, "delete %var% ;") || Token::Match(tok, "delete [ ] %var% ;")) { int varIdx = (tok->strAt(1) == "[") ? 3 : 1; unsigned int var = tok->tokAt(varIdx)->varId(); if (var) { if (freedVariables.find(var) != freedVariables.end()) doubleFreeError(tok, tok->strAt(varIdx)); else freedVariables.insert(var); } } // If this scope doesn't return, clear the set of previously freed variables else if (tok->str() == "}" && _tokenizer->IsScopeNoReturn(tok)) { freedVariables.clear(); closeDirVariables.clear(); } // If this scope is a "for" or "while" loop that contains "break" or "continue", // give up on trying to figure out the flow of execution and just clear the set // of previously freed variables. // TODO: There are false negatives. This bailout is only needed when the // loop will exit without free()'ing the memory on the last iteration. else if (tok->str() == "}" && tok->link() && tok->link()->tokAt(-1) && tok->link()->linkAt(-1) && Token::Match(tok->link()->linkAt(-1)->previous(), "while|for") && Token::findmatch(tok->link()->linkAt(-1), "break|continue ;", tok) != NULL) { freedVariables.clear(); closeDirVariables.clear(); } // If a variable is passed to a function, remove it from the set of previously freed variables else if (Token::Match(tok, "%var% (") && !Token::Match(tok, "printf|sprintf|snprintf|fprintf|wprintf|swprintf|fwprintf")) { // If this is a new function definition, clear all variables if (Token::simpleMatch(tok->next()->link(), ") {")) { freedVariables.clear(); closeDirVariables.clear(); } // If it is a function call, then clear those variables in its argument list else if (Token::simpleMatch(tok->next()->link(), ") ;")) { for (const Token* tok2 = tok->tokAt(2); tok2 != tok->linkAt(1); tok2 = tok2->next()) { if (Token::Match(tok2, "%var%")) { unsigned int var = tok2->varId(); if (var) { freedVariables.erase(var); closeDirVariables.erase(var); } } } } } // If a pointer is assigned a new value, remove it from the set of previously freed variables else if (Token::Match(tok, "%var% =")) { unsigned int var = tok->varId(); if (var) { freedVariables.erase(var); closeDirVariables.erase(var); } } // Any control statements in-between delete, free() or closedir() statements // makes it unclear whether any subsequent statements would be redundant. if (Token::Match(tok, "if|else|for|while|break|continue|goto|return|throw|switch")) { freedVariables.clear(); closeDirVariables.clear(); } } } void CheckOther::doubleFreeError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "doubleFree", "Memory pointed to by '" + varname +"' is freed twice."); } void CheckOther::doubleCloseDirError(const Token *tok, const std::string &varname) { reportError(tok, Severity::error, "doubleCloseDir", "Directory handle '" + varname +"' closed twice."); } namespace { struct ExpressionTokens { const Token *start; const Token *end; int count; bool inconclusiveFunction; ExpressionTokens(const Token *s, const Token *e): start(s), end(e), count(1), inconclusiveFunction(false) {} }; struct FuncFilter { FuncFilter(const Scope *scope, const Token *tok): _scope(scope), _tok(tok) {} bool operator()(const Function* func) const { 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->nestedIn && matchingFunc) || (!_scope && matchingFunc); } const Scope *_scope; const Token *_tok; }; bool inconclusiveFunctionCall(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) continue; if (prev->str() == ">") { // ignore template functions like boo() return true; } if (prev->isName()) { const Variable *v = 0; if (Token::Match(prev->tokAt(-2), "%var% .")) { const Token *scope = prev->tokAt(-2); v = scope->variable(); } // hard coded list of safe, no-side-effect functions if (v == 0 && Token::Match(prev, "strcmp|strncmp|strlen|wcscmp|wcsncmp|wcslen|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; } class Expressions { public: Expressions(const std::list &constFunctions) : _start(0), _lastTokens(0), _constFunctions(constFunctions) { } void endExpr(const Token *end) { const std::string &e = _expression.str(); if (!e.empty()) { std::map::iterator it = _expressions.find(e); bool lastInconclusive = _lastTokens && _lastTokens->inconclusiveFunction; if (it == _expressions.end()) { ExpressionTokens exprTokens(_start, end); exprTokens.inconclusiveFunction = lastInconclusive || inconclusiveFunctionCall( _constFunctions, exprTokens); _expressions.insert(std::make_pair(e, exprTokens)); _lastTokens = &_expressions.find(e)->second; } else { ExpressionTokens &expr = it->second; expr.count += 1; expr.inconclusiveFunction = expr.inconclusiveFunction || lastInconclusive; _lastTokens = &expr; } } _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; ExpressionTokens *_lastTokens; const std::list &_constFunctions; }; 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) { functionsByName[func->tokenDef->str()].push_back(&*func); } 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(constFunctions); 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(); for (; it != expressions.getMap().end(); ++it) { // check expression.. bool valid = true; unsigned int parentheses = 0; // () unsigned int brackets = 0; // [] // taking address? if (Token::Match(it->second.end->previous(), "%op% &")) { continue; } for (const Token *tok = it->second.start; tok && tok != it->second.end; tok = tok->next()) { if (tok->str() == "(") { ++parentheses; } else if (tok->str() == ")") { if (parentheses == 0) { valid = false; break; } --parentheses; } else if (tok->str() == "[") { ++brackets; } else if (tok->str() == "]") { if (brackets == 0) { valid = false; break; } --brackets; } else if (tok->type() == Token::eIncDecOp) { valid = false; break; } } if (!valid || parentheses!=0 || brackets!=0) continue; const ExpressionTokens &expr = it->second; if (expr.count > 1 && !expr.inconclusiveFunction) { duplicateExpressionError(expr.start, expr.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% %comp%|- %var% )|&&|%oror%|;|,") && tok->strAt(1) == tok->strAt(3)) { // float == float and float != float are valid NaN checks // float - float is a valid Inf check if (Token::Match(tok->tokAt(2), "==|!=|-") && tok->next()->varId()) { const Variable *var = tok->next()->variable(); if (var && var->typeStartToken() == var->typeEndToken()) { if (Token::Match(var->typeStartToken(), "float|double")) continue; } } // If either variable token is an expanded macro then // don't write the warning if (tok->next()->isExpandedMacro() || tok->tokAt(3)->isExpandedMacro()) continue; duplicateExpressionError(tok->next(), tok->tokAt(3), tok->strAt(2)); } else if (Token::Match(tok, ",|=|return|(|&&|%oror% %var% . %var% %comp%|- %var% . %var% )|&&|%oror%|;|,") && tok->strAt(1) == tok->strAt(5) && tok->strAt(3) == tok->strAt(7)) { // If either variable token is an expanded macro then // don't write the warning if (tok->next()->isExpandedMacro() || tok->tokAt(6)->isExpandedMacro()) continue; 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")) return; const Token *tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp|wcsncmp ( %str% , %str% ")) != NULL) { const std::string &str1 = tok->strAt(2); const std::string &str2 = tok->strAt(4); alwaysTrueFalseStringCompareError(tok, str1, str2); tok = tok->tokAt(5); } tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, "QString :: compare ( %str% , %str% )")) != NULL) { const std::string &str1 = tok->strAt(4); const std::string &str2 = tok->strAt(6); alwaysTrueFalseStringCompareError(tok, str1, str2); tok = tok->tokAt(7); } tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp|wcsncmp ( %var% , %var% ")) != NULL) { const std::string &str1 = tok->strAt(2); const std::string &str2 = tok->strAt(4); if (str1 == str2) alwaysTrueStringVariableCompareError(tok, str1, str2); tok = tok->tokAt(5); } tok = _tokenizer->tokens(); while (tok && (tok = Token::findmatch(tok, "!!+ %str% ==|!= %str% !!+")) != NULL) { const std::string &str1 = tok->strAt(1); const std::string &str2 = tok->strAt(3); alwaysTrueFalseStringCompareError(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) + ".."); reportError(tok, Severity::warning, "staticStringCompare", "Unnecessary comparison of static strings.\n" "The compared strings, '" + string1 + "' and '" + string2 + "', are always " + (str1==str2?"identical":"unequal") + ". " "Therefore the comparison is unnecessary and looks suspicious."); } 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::checkSuspiciousStringCompare() { if (!_settings->isEnabled("style")) return; const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (tok->next()->type() != Token::eComparisonOp) continue; const Token* varTok = tok; const Token* litTok = tok->tokAt(2); if (varTok->strAt(-1) == "+" || litTok->strAt(1) == "+") continue; if ((varTok->type() == Token::eString || varTok->type() == Token::eVariable) && (litTok->type() == Token::eString || litTok->type() == Token::eVariable) && litTok->type() != varTok->type()) { if (varTok->type() == Token::eString) std::swap(varTok, litTok); const Variable *var = varTok->variable(); if (var) { if (_tokenizer->isC() || (var->isPointer() && varTok->strAt(-1) != "*" && !Token::Match(varTok->next(), "[.([]"))) suspiciousStringCompareError(tok, var->name()); } } } } } void CheckOther::suspiciousStringCompareError(const Token* tok, const std::string& var) { reportError(tok, Severity::warning, "literalWithCharPtrCompare", "String literal compared with variable '" + var + "'. Did you intend to use strcmp() instead?"); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::checkModuloAlwaysTrueFalse() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if ((Token::Match(tok, "% %num% %comp% %num%")) && (!tok->tokAt(4) || !tok->tokAt(4)->isArithmeticalOp())) { if (MathLib::isLessEqual(tok->strAt(1), tok->strAt(3))) moduloAlwaysTrueFalseError(tok, tok->strAt(1)); } } } } void CheckOther::moduloAlwaysTrueFalseError(const Token* tok, const std::string& maxVal) { reportError(tok, Severity::warning, "moduloAlwaysTrueFalse", "Comparison of modulo result is predetermined, because it is always less than " + maxVal + "."); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- 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' on '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 (")) { const Token* const end = tok->linkAt(1); for (const Token *tok2 = tok->tokAt(2); tok2 != end; tok2 = tok2->next()) { if (tok2->isOp() && (!tok2->isExpandedMacro() || _settings->inconclusive) && !Token::Match(tok2, ">|<|&") && (Token::Match(tok2->previous(), "%var%") || tok2->str() != "*")) { if (!(Token::Match(tok2->previous(), "%type%") || Token::Match(tok2->next(), "%type%"))) { sizeofCalculationError(tok2, tok2->isExpandedMacro()); break; } } else if (tok2->type() == Token::eIncDecOp) sizeofCalculationError(tok2, tok2->isExpandedMacro()); } } } } void CheckOther::sizeofCalculationError(const Token *tok, bool inconclusive) { reportError(tok, Severity::warning, "sizeofCalculation", "Found calculation inside sizeof().", inconclusive); } //----------------------------------------------------------------------------- // Check for code like: // seteuid(geteuid()) or setuid(getuid()), which first gets and then sets the // (effective) user id to itself. Very often this indicates a copy and paste // error. //----------------------------------------------------------------------------- void CheckOther::redundantGetAndSetUserId() { if (_settings->isEnabled("warning") && _settings->standards.posix) { for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "setuid ( getuid ( ) )") || Token::simpleMatch(tok, "seteuid ( geteuid ( ) )") || Token::simpleMatch(tok, "setgid ( getgid ( ) )") || Token::simpleMatch(tok, "setegid ( getegid ( ) )")) { redundantGetAndSetUserIdError(tok); } } } } void CheckOther::redundantGetAndSetUserIdError(const Token *tok) { reportError(tok, Severity::warning, "redundantGetAndSetUserId", "Redundant get and set of user id.\n" "Redundant statement without any effect. First the user id is retrieved" "by get(e)uid() and then set with set(e)uid().", false); } //----------------------------------------------------------------------------- // Check for code like sizeof()*sizeof() or sizeof(ptr)/value //----------------------------------------------------------------------------- void CheckOther::suspiciousSizeofCalculation() { if (!_settings->isEnabled("style") || !_settings->inconclusive) return; for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) { if (Token::simpleMatch(tok, "sizeof (")) { const Token* const end = tok->linkAt(1); const Variable* var = end->previous()->variable(); if (end->strAt(-1) == "*" || (var && var->isPointer() && !var->isArray())) { if (end->strAt(1) == "/") divideSizeofError(tok); } else if (Token::simpleMatch(end, ") * sizeof")) multiplySizeofError(tok); } } } void CheckOther::multiplySizeofError(const Token *tok) { reportError(tok, Severity::warning, "multiplySizeof", "Multiplying sizeof() with sizeof() indicates a logic error.", true); } void CheckOther::divideSizeofError(const Token *tok) { reportError(tok, Severity::warning, "divideSizeof", "Division of result of sizeof() on pointer type.\n" "Division of result of sizeof() on pointer type. sizeof() returns the size of the pointer, " "not the size of the memory area it points to.", true); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::checkAssignBoolToPointer() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "!!* %var% = %bool% ;")) { const Variable *var1(tok->next()->variable()); // Is variable a pointer? if (var1 && var1->isPointer()) assignBoolToPointerError(tok->next()); } } } } void CheckOther::assignBoolToPointerError(const Token *tok) { reportError(tok, Severity::error, "assignBoolToPointer", "Boolean value assigned to pointer."); } //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- void CheckOther::checkComparisonOfBoolExpressionWithInt() { if (!_settings->isEnabled("style")) return; const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { // Skip template parameters if (tok->str() == "<" && tok->link()) { tok = tok->link(); continue; } const Token* numTok = 0; const Token* opTok = 0; char op = 0; if (Token::Match(tok, "&&|%oror% %any% ) %comp% %any%")) { numTok = tok->tokAt(4); opTok = tok->tokAt(3); if (Token::Match(opTok, "<|>")) op = opTok->str()[0]; } else if (Token::Match(tok, "%any% %comp% ( %any% &&|%oror%")) { numTok = tok; opTok = tok->next(); if (Token::Match(opTok, "<|>")) op = opTok->str()[0]=='>'?'<':'>'; } else if (Token::Match(tok, "! %var% %comp% %any%")) { numTok = tok->tokAt(3); opTok = tok->tokAt(2); if (Token::Match(opTok, "<|>")) op = opTok->str()[0]; } else if (Token::Match(tok, "%any% %comp% ! %var%")) { numTok = tok; opTok = tok->next(); if (Token::Match(opTok, "<|>")) op = opTok->str()[0]=='>'?'<':'>'; } if (numTok && opTok) { if (numTok->isNumber()) { if (((numTok->str() != "0" && numTok->str() != "1") || !Token::Match(opTok, "!=|==")) && !((op == '<' && numTok->str() == "1") || (op == '>' && numTok->str() == "0"))) comparisonOfBoolExpressionWithIntError(tok, true); } else if (isNonBoolStdType(numTok->variable())) comparisonOfBoolExpressionWithIntError(tok, false); } } } } void CheckOther::comparisonOfBoolExpressionWithIntError(const Token *tok, bool n0o1) { if (n0o1) reportError(tok, Severity::warning, "compareBoolExpressionWithInt", "Comparison of a boolean expression with an integer other than 0 or 1."); else reportError(tok, Severity::warning, "compareBoolExpressionWithInt", "Comparison of a boolean expression with an integer."); } //--------------------------------------------------------------------------- // Check testing sign of unsigned variables and pointers. //--------------------------------------------------------------------------- void CheckOther::checkSignOfUnsignedVariable() { if (!_settings->isEnabled("style")) return; const bool inconclusive = _tokenizer->codeWithTemplates(); if (inconclusive && !_settings->inconclusive) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; // check all the code in the function for (const Token *tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "%var% <|<= 0") && tok->varId() && !Token::Match(tok->previous(), "++|--|)|+|-|*|/|~|<<|>>") && !Token::Match(tok->tokAt(3), "+|-")) { const Variable *var = tok->variable(); if (var && var->typeEndToken()->isUnsigned()) unsignedLessThanZeroError(tok, var->name(), inconclusive); else if (var && var->isPointer() && tok->strAt(-1) != "*") pointerLessThanZeroError(tok, inconclusive); } else if (Token::Match(tok, "0 >|>= %var%") && tok->tokAt(2)->varId() && !Token::Match(tok->tokAt(3), "+|-|*|/") && !Token::Match(tok->previous(), "+|-|<<|>>|~")) { const Variable *var = tok->tokAt(2)->variable(); if (var && var->typeEndToken()->isUnsigned()) unsignedLessThanZeroError(tok, var->name(), inconclusive); else if (var && var->isPointer() && !Token::Match(tok->tokAt(3), "[.[]")) pointerLessThanZeroError(tok, inconclusive); } else if (Token::Match(tok, "0 <= %var%") && tok->tokAt(2)->varId() && !Token::Match(tok->tokAt(3), "+|-|*|/") && !Token::Match(tok->previous(), "+|-|<<|>>|~")) { const Variable *var = tok->tokAt(2)->variable(); if (var && var->typeEndToken()->isUnsigned()) unsignedPositiveError(tok, var->name(), inconclusive); else if (var && var->isPointer() && !Token::Match(tok->tokAt(3), "[.[]")) pointerPositiveError(tok, inconclusive); } else if (Token::Match(tok, "%var% >= 0") && tok->varId() && !Token::Match(tok->previous(), "++|--|)|+|-|*|/|~|<<|>>") && !Token::Match(tok->tokAt(3), "+|-")) { const Variable *var = tok->variable(); if (var && var->typeEndToken()->isUnsigned()) unsignedPositiveError(tok, var->name(), inconclusive); else if (var && var->isPointer() && tok->strAt(-1) != "*") pointerPositiveError(tok, inconclusive); } } } } void CheckOther::unsignedLessThanZeroError(const Token *tok, const std::string &varname, bool inconclusive) { if (inconclusive) { reportError(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.", true); } else { reportError(tok, Severity::style, "unsignedLessThanZero", "Checking if unsigned variable '" + varname + "' is less than zero.\n" "The unsigned variable '" + varname + "' will never be negative so it " "is either pointless or an error to check if it is."); } } void CheckOther::pointerLessThanZeroError(const Token *tok, bool inconclusive) { reportError(tok, Severity::style, "pointerLessThanZero", "A pointer can not be negative so it is either pointless or an error to check if it is.", inconclusive); } void CheckOther::unsignedPositiveError(const Token *tok, const std::string &varname, bool inconclusive) { if (inconclusive) { reportError(tok, Severity::style, "unsignedPositive", "Unsigned variable '" + varname + "' can't be negative so it is unnecessary to test it.\n" "The unsigned variable '" + varname + "' can't be negative so it is unnecessary to test it. " "It's not known if the used constant is a " "template parameter or not and therefore this message might be a false warning", true); } else { reportError(tok, Severity::style, "unsignedPositive", "Unsigned variable '" + varname + "' can't be negative so it is unnecessary to test it."); } } void CheckOther::pointerPositiveError(const Token *tok, bool inconclusive) { reportError(tok, Severity::style, "pointerPositive", "A pointer can not be negative so it is either pointless or an error to check if it is not.", inconclusive); } /* This check rule works for checking the "const A a = getA()" usage when getA() returns "const A &" or "A &". In most scenarios, "const A & a = getA()" will be more efficient. */ void CheckOther::checkRedundantCopy() { if (!_settings->isEnabled("performance") || _tokenizer->isC()) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (const Token *tok = _tokenizer->tokens(); tok; tok=tok->next()) { const char *expect_end_token; if (Token::Match(tok, "const %type% %var% =")) { //match "const A a =" usage expect_end_token = ";"; } else if (Token::Match(tok, "const %type% %var% (")) { //match "const A a (" usage expect_end_token = ")"; } else { continue; } if (tok->strAt(1) == tok->strAt(4)) //avoid "const A a = A();" continue; if (!symbolDatabase->isClassOrStruct(tok->next()->str())) //avoid when %type% is standard type continue; const Token *var_tok = tok->tokAt(2); tok = tok->tokAt(4); while (tok &&Token::Match(tok,"%var% .")) tok = tok->tokAt(2); if (!Token::Match(tok, "%var% (")) break; const Token *match_end = (tok->next()->link()!=NULL)?tok->next()->link()->next():NULL; if (match_end==NULL || !Token::Match(match_end,expect_end_token)) //avoid usage like "const A a = getA()+3" break; const Function* func = tok->function(); if (func && func->tokenDef->previous() && func->tokenDef->previous()->str() == "&") { redundantCopyError(var_tok,var_tok->str()); } } } void CheckOther::redundantCopyError(const Token *tok,const std::string& varname) { reportError(tok, Severity::performance,"redundantCopyLocalConst", "Use const reference for '" + varname + "' to avoid unnecessary data copying.\n" "The const variable '"+varname+"' is assigned a copy of the data. You can avoid " "the unnecessary data copying by converting '" + varname + "' to const reference."); } //--------------------------------------------------------------------------- // Checking for shift by negative values //--------------------------------------------------------------------------- void CheckOther::checkNegativeBitwiseShift() { const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if ((Token::Match(tok,"%var% >>|<< %num%") || Token::Match(tok,"%num% >>|<< %num%")) && !Token::Match(tok->previous(),">>|<<")) { if (tok->isName()) { const Variable *var = tok->variable(); if (var && var->typeStartToken()->isStandardType() && (tok->strAt(2))[0] == '-') negativeBitwiseShiftError(tok); } else { if ((tok->strAt(2))[0] == '-') negativeBitwiseShiftError(tok); } } } } } void CheckOther::negativeBitwiseShiftError(const Token *tok) { reportError(tok, Severity::error, "shiftNegative", "Shifting by a negative value."); } //--------------------------------------------------------------------------- // Check for incompletely filled buffers. //--------------------------------------------------------------------------- void CheckOther::checkIncompleteArrayFill() { if (!_settings->inconclusive || !_settings->isEnabled("style")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) { if (Token::Match(tok, "memset|memcpy|memmove ( %var% ,") && Token::Match(tok->linkAt(1)->tokAt(-2), ", %num% )")) { const Variable *var = tok->tokAt(2)->variable(); if (!var || !var->isArray() || var->dimensions().empty() || !var->dimension(0)) continue; if (MathLib::toLongNumber(tok->linkAt(1)->strAt(-1)) == var->dimension(0)) { unsigned int size = _tokenizer->sizeOfType(var->typeStartToken()); if ((size != 1 && size != 100 && size != 0) || var->typeEndToken()->str() == "*") incompleteArrayFillError(tok, var->name(), tok->str(), false); else if (var->typeStartToken()->str() == "bool" && _settings->isEnabled("portability")) // sizeof(bool) is not 1 on all platforms incompleteArrayFillError(tok, var->name(), tok->str(), true); } } } } } void CheckOther::incompleteArrayFillError(const Token* tok, const std::string& buffer, const std::string& function, bool boolean) { if (boolean) reportError(tok, Severity::portability, "incompleteArrayFill", "Array '" + buffer + "' might be filled incompletely. Did you forget to multiply the size given to '" + function + "()' with 'sizeof(*" + buffer + ")'?\n" "The array '" + buffer + "' is filled incompletely. The function '" + function + "()' needs the size given in bytes, but the type 'bool' is larger than 1 on some platforms. Did you forget to multiply the size with 'sizeof(*" + buffer + ")'?", true); else reportError(tok, Severity::warning, "incompleteArrayFill", "Array '" + buffer + "' is filled incompletely. Did you forget to multiply the size given to '" + function + "()' with 'sizeof(*" + buffer + ")'?\n" "The array '" + buffer + "' is filled incompletely. The function '" + function + "()' needs the size given in bytes, but an element of the given array is larger than one byte. Did you forget to multiply the size with 'sizeof(*" + buffer + ")'?", true); } void CheckOther::oppositeInnerCondition() { // FIXME: This check is experimental because of #4170 and #4186. Fix those tickets and remove the "experimental". if (!_settings->isEnabled("style") || !_settings->inconclusive || !_settings->experimental) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); for (std::list::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) { const Token* const toke = scope->classDef; if (scope->type == Scope::eIf && toke) { const Token *op1Tok, *op2Tok; op1Tok = scope->classDef->tokAt(2); op2Tok = scope->classDef->tokAt(4); if (scope->classDef->strAt(6) == "{") { const char *oppositeCondition = NULL; if (scope->classDef->strAt(3) == "==") oppositeCondition = "if ( %any% !=|<|>|<=|>= %any% )"; else if (scope->classDef->strAt(3) == "!=") oppositeCondition = "if ( %any% ==|>=|<= %any% )"; else if (scope->classDef->strAt(3) == "<") oppositeCondition = "if ( %any% >|>=|== %any% )"; else if (scope->classDef->strAt(3) == "<=") oppositeCondition = "if ( %any% > %any% )"; else if (scope->classDef->strAt(3) == ">") oppositeCondition = "if ( %any% <|<=|== %any% )"; else if (scope->classDef->strAt(3) == ">=") oppositeCondition = "if ( %any% < %any% )"; if (oppositeCondition) { int flag = 0; for (const Token* tok = scope->classStart; tok != scope->classEnd && flag == 0; tok = tok->next()) { if ((tok->str() == op1Tok->str() || tok->str() == op2Tok->str()) && tok->strAt(1) == "=") break; else if (Token::Match(tok, "%any% ( %any% )")) { if ((tok->strAt(2) == op1Tok->str() || tok->strAt(2) == op2Tok->str())) break; } else if (Token::Match(tok, "%any% ( %any% , %any%")) { for (const Token* tok2 = tok->next(); tok2 != tok->linkAt(1); tok2 = tok2->next()) { if (tok2->str() == op1Tok->str()) { flag = 1; break; } } } else if (Token::Match(tok, oppositeCondition)) { if ((tok->strAt(2) == op1Tok->str() && tok->strAt(4) == op2Tok->str()) || (tok->strAt(2) == op2Tok->str() && tok->strAt(4) == op1Tok->str())) oppositeInnerConditionError(toke); } } } } } } } void CheckOther::oppositeInnerConditionError(const Token *tok) { reportError(tok, Severity::warning, "oppositeInnerCondition", "Opposite conditions in nested 'if' blocks lead to a dead code block.", true); } void CheckOther::checkVarFuncNullUB() { if (!_settings->isEnabled("portability")) return; const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase(); const std::size_t functions = symbolDatabase->functionScopes.size(); for (std::size_t i = 0; i < functions; ++i) { const Scope * scope = symbolDatabase->functionScopes[i]; for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) { // Is NULL passed to a function? if (Token::Match(tok,"[(,] NULL [,)]")) { // Locate function name in this function call. const Token *ftok = tok; std::size_t argnr = 1; while (ftok && ftok->str() != "(") { if (ftok->str() == ")") ftok = ftok->link(); else if (ftok->str() == ",") ++argnr; ftok = ftok->previous(); } ftok = ftok ? ftok->previous() : NULL; if (ftok && ftok->isName()) { // If this is a variadic function then report error const Function *f = ftok->function(); if (f && f->argCount() <= argnr) { const Token *tok2 = f->argDef; tok2 = tok2 ? tok2->link() : NULL; // goto ')' if (Token::simpleMatch(tok2->tokAt(-3), ". . .")) varFuncNullUBError(tok); } } } } } } void CheckOther::varFuncNullUBError(const Token *tok) { reportError(tok, Severity::portability, "varFuncNullUB", "Passing NULL after the last typed argument to a variadic function leads to undefined behaviour.\n" "Passing NULL after the last typed argument to a variadic function leads to undefined behaviour.\n" "The C99 standard, in section 7.15.1.1, states that if the type used by va_arg() is not compatible with the type of the actual next argument (as promoted according to the default argument promotions), the behavior is undefined.\n" "The value of the NULL macro is an implementation-defined null pointer constant (7.17), which can be any integer constant expression with the value 0, or such an expression casted to (void*) (6.3.2.3). This includes values like 0, 0L, or even 0LL.\n" "In practice on common architectures, this will cause real crashes if sizeof(int) != sizeof(void*), and NULL is defined to 0 or any other null pointer constant that promotes to int.\n" "To reproduce you might be able to use this little code example on 64bit platforms. If the output includes \"ERROR\", the sentinel had only 4 out of 8 bytes initialized to zero and was not detected as the final argument to stop argument processing via va_arg(). Changing the 0 to (void*)0 or 0L will make the \"ERROR\" output go away.\n" "#include \n" "#include \n" "\n" "void f(char *s, ...) {\n" " va_list ap;\n" " va_start(ap,s);\n" " for (;;) {\n" " char *p = va_arg(ap,char*);\n" " printf(\"%018p, %s\n\", p, (long)p & 255 ? p : \"\");\n" " if(!p) break;\n" " }\n" " va_end(ap);\n" "}\n" "\n" "void g() {\n" " char *s2 = \"x\";\n" " char *s3 = \"ERROR\";\n" "\n" " // changing 0 to 0L for the 7th argument (which is intended to act as sentinel) makes the error go away on x86_64\n" " f(\"first\", s2, s2, s2, s2, s2, 0, s3, (char*)0);\n" "}\n" "\n" "void h() {\n" " int i;\n" " volatile unsigned char a[1000];\n" " for (i = 0; i