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cppcheck/lib/checkother.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2014 Daniel Marjamäki and Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
#include "checkother.h"
#include "mathlib.h"
#include "symboldatabase.h"
#include <cmath> // fabs()
#include <stack>
#include <algorithm> // find_if()
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckOther instance;
}
static bool astIsFloat(const Token *tok, bool unknown)
{
if (tok->astOperand1() && tok->str() != "?" && astIsFloat(tok->astOperand1(),unknown))
return true;
if (tok->astOperand2() && astIsFloat(tok->astOperand2(), unknown))
return true;
if (tok->isNumber())
return MathLib::isFloat(tok->str());
if (tok->isName()) {
// TODO: check function calls, struct members, arrays, etc also
if (!tok->variable())
return unknown;
return Token::findmatch(tok->variable()->typeStartToken(), "float|double", tok->variable()->typeEndToken()->next(), 0) != nullptr;
}
if (tok->isOp())
return false;
return unknown;
}
static bool isConstExpression(const Token *tok, const std::set<std::string> &constFunctions)
{
if (!tok)
return true;
if (tok->isName() && tok->next()->str() == "(") {
if (!tok->function() && !Token::Match(tok->previous(), ".|::") && constFunctions.find(tok->str()) == constFunctions.end())
return false;
else if (tok->function() && !tok->function()->isConst)
return false;
}
if (tok->type() == Token::eIncDecOp)
return false;
// bailout when we see ({..})
if (tok->str() == "{")
return false;
return isConstExpression(tok->astOperand1(),constFunctions) && isConstExpression(tok->astOperand2(),constFunctions);
}
bool isSameExpression(const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions)
{
if (tok1 == nullptr && tok2 == nullptr)
return true;
if (tok1 == nullptr || tok2 == nullptr)
return false;
if (tok1->str() == "." && tok1->astOperand1() && tok1->astOperand1()->str() == "this")
tok1 = tok1->astOperand2();
if (tok2->str() == "." && tok2->astOperand1() && tok2->astOperand1()->str() == "this")
tok2 = tok2->astOperand2();
if (tok1->str() != tok2->str() || tok1->varId() != tok2->varId())
return false;
if (tok1->str() == "." && tok1->originalName() != tok2->originalName())
return false;
if (tok1->isExpandedMacro() || tok2->isExpandedMacro())
return false;
if (tok1->isName() && tok1->next()->str() == "(") {
if (!tok1->function() && !Token::Match(tok1->previous(), ".|::") && constFunctions.find(tok1->str()) == constFunctions.end() && !tok1->isAttributeConst() && !tok1->isAttributePure())
return false;
else if (tok1->function() && !tok1->function()->isConst && !tok1->function()->isAttributeConst() && !tok1->function()->isAttributePure())
return false;
}
// templates/casts
if ((Token::Match(tok1, "%var% <") && tok1->next()->link()) ||
(Token::Match(tok2, "%var% <") && tok2->next()->link())) {
// non-const template function that is not a dynamic_cast => return false
if (Token::simpleMatch(tok1->next()->link(), "> (") &&
!(tok1->function() && tok1->function()->isConst) &&
tok1->str() != "dynamic_cast")
return false;
// some template/cast stuff.. check that the template arguments are same
const Token *t1 = tok1->next();
const Token *t2 = tok2->next();
const Token *end1 = tok1->next()->link();
const Token *end2 = tok2->next()->link();
while (t1 && t2 && t1 != end1 && t2 != end2) {
if (t1->str() != t2->str())
return false;
t1 = t1->next();
t2 = t2->next();
}
if (t1 != end1 || t2 != end2)
return false;
}
if (tok1->type() == Token::eIncDecOp || tok1->isAssignmentOp())
return false;
if (tok1->str() == "(" && tok1->previous() && !tok1->previous()->isName()) { // cast => assert that the casts are equal
const Token *t1 = tok1->next();
const Token *t2 = tok2->next();
while (t1 && t2 && t1->str() == t2->str() && (t1->isName() || t1->str() == "*")) {
t1 = t1->next();
t2 = t2->next();
}
if (!t1 || !t2 || t1->str() != ")" || t2->str() != ")")
return false;
}
// bailout when we see ({..})
if (tok1->str() == "{")
return false;
bool noncommuative_equals =
isSameExpression(tok1->astOperand1(), tok2->astOperand1(), constFunctions);
noncommuative_equals = noncommuative_equals &&
isSameExpression(tok1->astOperand2(), tok2->astOperand2(), constFunctions);
if (noncommuative_equals)
return true;
bool commutative = tok1->astOperand1() && tok1->astOperand2() && Token::Match(tok1, "%or%|%oror%|+|*|&|&&|^|==|!=");
bool commuative_equals = commutative &&
isSameExpression(tok1->astOperand2(), tok2->astOperand1(), constFunctions);
commuative_equals = commuative_equals &&
isSameExpression(tok1->astOperand1(), tok2->astOperand2(), constFunctions);
return commuative_equals;
}
static bool isOppositeCond(const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions)
{
if (!cond1 || !cond1->isComparisonOp() || !cond2 || !cond2->isComparisonOp())
return false;
const std::string &comp1 = cond1->str();
// condition found .. get comparator
std::string comp2;
if (isSameExpression(cond1->astOperand1(), cond2->astOperand1(), constFunctions) &&
isSameExpression(cond1->astOperand2(), cond2->astOperand2(), constFunctions)) {
comp2 = cond2->str();
} else if (isSameExpression(cond1->astOperand1(), cond2->astOperand2(), constFunctions) &&
isSameExpression(cond1->astOperand2(), cond2->astOperand1(), constFunctions)) {
comp2 = cond2->str();
if (comp2[0] == '>')
comp2[0] = '<';
else if (comp2[0] == '<')
comp2[0] = '>';
}
// is condition opposite?
return ((comp1 == "==" && comp2 == "!=") ||
(comp1 == "!=" && comp2 == "==") ||
(comp1 == "<" && comp2 == ">=") ||
(comp1 == "<" && comp2 == ">") ||
(comp1 == "<=" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<=") ||
(comp1 == ">" && comp2 == "<") ||
(comp1 == ">=" && comp2 == "<"));
}
//----------------------------------------------------------------------------------
// The return value of fgetc(), getc(), ungetc(), getchar() etc. is an integer value.
// If this return value is stored in a character variable and then compared
// to compared to EOF, which is an integer, the comparison maybe be false.
//
// Reference:
// - Ticket #160
// - http://www.cplusplus.com/reference/cstdio/fgetc/
// - http://www.cplusplus.com/reference/cstdio/getc/
// - http://www.cplusplus.com/reference/cstdio/getchar/
// - http://www.cplusplus.com/reference/cstdio/ungetc/ ...
//----------------------------------------------------------------------------------
void CheckOther::checkCastIntToCharAndBack()
{
if (!_settings->isEnabled("warning"))
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];
std::map<unsigned int, std::string> vars;
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
if (Token::Match(tok, "%var% = fclose|fflush|fputc|fputs|fscanf|getchar|getc|fgetc|putchar|putc|puts|scanf|sscanf|ungetc (")) {
const Variable *var = tok->variable();
if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
vars[tok->varId()] = tok->strAt(2);
}
} else if (Token::Match(tok, "EOF %comp% ( %var% = fclose|fflush|fputc|fputs|fscanf|getchar|getc|fgetc|putchar|putc|puts|scanf|sscanf|ungetc (")) {
tok = tok->tokAt(3);
const Variable *var = tok->variable();
if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
checkCastIntToCharAndBackError(tok, tok->strAt(2));
}
} else if (Token::Match(tok, "EOF %comp% ( %var% = std :: cin . get (") || Token::Match(tok, "EOF %comp% ( %var% = cin . get (")) {
tok = tok->tokAt(3);
const Variable *var = tok->variable();
if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
checkCastIntToCharAndBackError(tok, "cin.get");
}
} else if (Token::Match(tok, "%var% = std :: cin . get (") || Token::Match(tok, "%var% = cin . get (")) {
const Variable *var = tok->variable();
if (var && var->typeEndToken()->str() == "char" && !var->typeEndToken()->isSigned()) {
vars[tok->varId()] = "cin.get";
}
}
if (Token::Match(tok, "%var% %comp% EOF")) {
if (vars.find(tok->varId()) != vars.end()) {
checkCastIntToCharAndBackError(tok, vars[tok->varId()]);
}
} else if (Token::Match(tok, "EOF %comp% %var%")) {
tok = tok->tokAt(2);
if (vars.find(tok->varId()) != vars.end()) {
checkCastIntToCharAndBackError(tok, vars[tok->varId()]);
}
}
}
}
}
void CheckOther::checkCastIntToCharAndBackError(const Token *tok, const std::string &strFunctionName)
{
reportError(
tok,
Severity::warning,
"checkCastIntToCharAndBack",
"Storing "+ strFunctionName +"() return value in char variable and then comparing with EOF.\n"
"When saving "+ strFunctionName +"() return value in char variable there is loss of precision. "
" When "+ strFunctionName +"() returns EOF this value is truncated. Comparing the char "
"variable with EOF can have unexpected results. For instance a loop \"while (EOF != (c = "+ strFunctionName +"());\" "
"loops forever on some compilers/platforms and on other compilers/platforms it will stop "
"when the file contains a matching character."
);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
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()) {
// ? operator where lhs is arithmetical expression
if (tok->str() != "?" || !tok->astOperand1() || !tok->astOperand1()->isArithmeticalOp() || !tok->astOperand1()->isCalculation())
continue;
// Is code clarified by parentheses already?
const Token *tok2 = tok->astOperand1();
for (; tok2; tok2 = tok2->next()) {
if (tok2->str() == "(")
tok2 = tok2->link();
else if (tok2->str() == ")" || tok2->str() == "?")
break;
}
if (tok2 && tok2->str() == "?")
clarifyCalculationError(tok, tok->astOperand1()->str());
}
}
}
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<WS_CHILD|WS_VISIBLE>::..
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("warning"))
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 && tok != scope->classEnd; tok = tok->next()) {
if (Token::Match(tok, "* %var%") && tok->astOperand1()) {
const Token *tok2=tok->previous();
while (tok2 && tok2->str() == "*")
tok2 = tok2->previous();
if (Token::Match(tok2, "[{};]")) {
tok2 = tok->astOperand1();
if (Token::Match(tok2, "++|-- [;,]"))
clarifyStatementError(tok2);
}
}
}
}
}
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)++;'?");
}
void CheckOther::checkSuspiciousSemicolon()
{
if (!_settings->inconclusive || !_settings->isEnabled("warning"))
return;
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
// Look for "if(); {}", "for(); {}" or "while(); {}"
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type == Scope::eIf || i->type == Scope::eElse || 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->classDef);
}
}
}
}
void CheckOther::SuspiciousSemicolonError(const Token* tok)
{
reportError(tok, Severity::warning, "suspiciousSemicolon",
"Suspicious use of ; at the end of '" + (tok ? tok->str() : std::string()) + "' statement.", true);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::warningOldStylePointerCast()
{
// Only valid on C++ code
if (!_settings->isEnabled("style") || !_tokenizer->isCPP())
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::size_t i = 0; i < symbolDatabase->functionScopes.size(); ++i) {
const Scope * scope = symbolDatabase->functionScopes[i];
const Token* tok;
if (scope->function && scope->function->isConstructor())
tok = scope->classDef;
else
tok = scope->classStart;
for (; tok && tok != scope->classEnd; tok = tok->next()) {
// Old style pointer casting..
if (!Token::Match(tok, "( const| %type% * ) (| %var%|%num%|%bool%|%char%|%str%"))
continue;
if (tok->strAt(1) == "const")
tok = tok->next();
if (tok->strAt(4) == "0") // Casting nullpointers is safe
continue;
// Is "type" a class?
if (_tokenizer->getSymbolDatabase()->isClassOrStruct(tok->strAt(1)))
cstyleCastError(tok);
}
}
}
void CheckOther::cstyleCastError(const Token *tok)
{
reportError(tok, Severity::style, "cstyleCast",
"C-style pointer casting\n"
"C-style pointer casting detected. C++ offers four different kinds of casts as replacements: "
"static_cast, const_cast, dynamic_cast and reinterpret_cast. A C-style cast could evaluate to "
"any of those automatically, thus it is considered safer if the programmer explicitly states "
"which kind of cast is expected. See also: https://www.securecoding.cert.org/confluence/display/cplusplus/EXP05-CPP.+Do+not+use+C-style+casts.");
}
//---------------------------------------------------------------------------
// 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("warning") && !_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 = nullptr;
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.");
}
//---------------------------------------------------------------------------
// 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->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->isArgument() && ((dim=var->dimension(0U)) < 2)) {
const std::string strDim = MathLib::toString(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", "Buffer '" + strVarName + "' must have size of 2 integers if used as parameter of pipe().\n"
"The pipe()/pipe2() system command takes an argument, which is an array of exactly two integers.\n"
"The variable '" + strVarName + "' is an array of size " + strDim + ", which does not match.");
}
//---------------------------------------------------------------------------
// 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<unsigned int, const Token*>& container, const SymbolDatabase* symbolDatabase)
{
for (std::map<unsigned int, const Token*>::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;
}
}
static void eraseMemberAssignments(const unsigned int varId, std::map<unsigned int, std::set<unsigned int> > &membervars, std::map<unsigned int, const Token*> &varAssignments)
{
const std::map<unsigned int, std::set<unsigned int> >::const_iterator it = membervars.find(varId);
if (it != membervars.end()) {
const std::set<unsigned int> v = it->second;
for (std::set<unsigned int>::const_iterator vit = v.begin(); vit != v.end(); ++vit) {
varAssignments.erase(*vit);
if (*vit != varId)
eraseMemberAssignments(*vit, membervars, varAssignments);
}
}
}
void CheckOther::checkRedundantAssignment()
{
const bool performance = _settings->isEnabled("performance");
const bool warning = _settings->isEnabled("warning");
if (!warning && !performance)
return;
const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (!scope->isExecutable())
continue;
std::map<unsigned int, const Token*> varAssignments;
std::map<unsigned int, const Token*> memAssignments;
std::map<unsigned int, std::set<unsigned int> > membervars;
std::set<unsigned int> initialized;
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 && !Token::Match(tok,"%var% (")) {
// Set initialization flag
if (!Token::Match(tok, "%var% ["))
initialized.insert(tok->varId());
else {
const Token *tok2 = tok->next();
while (tok2 && tok2->str() == "[")
tok2 = tok2->link()->next();
if (tok2 && tok2->str() != ";")
initialized.insert(tok->varId());
}
const Token *startToken = tok;
while (Token::Match(startToken, "%var%|::|.")) {
startToken = startToken->previous();
if (Token::Match(startToken, "%var% . %var%"))
membervars[startToken->varId()].insert(startToken->tokAt(2)->varId());
}
std::map<unsigned int, const Token*>::iterator it = varAssignments.find(tok->varId());
if (tok->next()->isAssignmentOp() && Token::Match(startToken, "[;{}]")) { // 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* const func = tok2->function();
const Variable* const 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) && warning)
redundantAssignmentInSwitchError(it->second, tok, tok->str());
else if (performance) {
const bool nonlocal = nonLocal(it->second->variable());
if (_settings->inconclusive || !nonlocal) // see #5089 - report inconclusive only when requested
redundantAssignmentError(it->second, tok, tok->str(), nonlocal); // Inconclusive for non-local variables
}
}
it->second = tok;
}
if (!Token::simpleMatch(tok->tokAt(2), "0 ;") || (tok->variable() && tok->variable()->nameToken() != tok->tokAt(-2)))
varAssignments[tok->varId()] = tok;
memAssignments.erase(tok->varId());
eraseMemberAssignments(tok->varId(), membervars, varAssignments);
} else if (tok->next()->type() == Token::eIncDecOp || (tok->previous()->type() == Token::eIncDecOp && tok->strAt(1) == ";")) { // Variable incremented/decremented; Prefix-Increment is only suspicious, if its return value is unused
varAssignments[tok->varId()] = tok;
memAssignments.erase(tok->varId());
eraseMemberAssignments(tok->varId(), membervars, varAssignments);
} 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
const bool memfunc = Token::Match(tok, "memcpy|memmove|memset|strcpy|strncpy|sprintf|snprintf|strcat|strncat|wcscpy|wcsncpy|swprintf|wcscat|wcsncat");
if (tok->varId()) // operator() or function pointer
varAssignments.erase(tok->varId());
if (memfunc && tok->strAt(-1) != "(" && tok->strAt(-1) != "=") {
const Token* param1 = tok->tokAt(2);
writtenArgumentsEnd = param1->next();
if (param1->varId() && param1->strAt(1) == "," && !Token::Match(tok, "strcat|strncat|wcscat|wcsncat")) {
if (tok->str() == "memset" && initialized.find(param1->varId()) == initialized.end() && param1->variable() && param1->variable()->isLocal() && param1->variable()->isArray())
initialized.insert(param1->varId());
else if (memAssignments.find(param1->varId()) == memAssignments.end())
memAssignments[param1->varId()] = tok;
else {
const std::map<unsigned int, const Token*>::iterator it = memAssignments.find(param1->varId());
if (warning && scope->type == Scope::eSwitch && Token::findmatch(it->second, "default|case", tok))
redundantCopyInSwitchError(it->second, tok, param1->str());
else if (performance)
redundantCopyError(it->second, tok, param1->str());
}
}
} else if (scope->type == Scope::eSwitch) { // Avoid false positives if noreturn function is called in switch
const Function* const 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<const Token*> 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<const Token*> 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<const Token*> 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<const Token*> 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("warning"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
// Find the beginning of a switch. E.g.:
// switch (var) { ...
for (std::list<Scope>::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<unsigned int, const Token*> varsWithBitsSet;
std::map<unsigned int, std::string> 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<unsigned int, const Token*>::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<Scope>::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<std::pair<Token *, bool> > ifnest;
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();
ifnest.push(std::make_pair(tok2->link(), false));
justbreak = false;
} else if (Token::simpleMatch(tok2, "while (")) {
tok2 = tok2->next()->link()->next();
if (tok2->link()) // skip over "do { } while ( ) ;" case
tok2 = tok2->link();
justbreak = false;
} else if (Token::simpleMatch(tok2, "do {")) {
tok2 = tok2->next()->link();
justbreak = false;
} else if (Token::simpleMatch(tok2, "for (")) {
tok2 = tok2->next()->link()->next()->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")) {
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() == "}") {
if (!ifnest.empty() && tok2 == ifnest.top().first) {
if (tok2->next()->str() == "else") {
tok2 = tok2->tokAt(2);
ifnest.pop();
ifnest.push(std::make_pair(tok2->link(), justbreak));
justbreak = false;
} else {
justbreak &= ifnest.top().second;
ifnest.pop();
}
}
} 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("warning"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::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* finding = nullptr;
for (const Token* tok2 = tok->next(); tok2; tok2 = tok2->next()) {
if (tok2->str() == ":")
break;
if (Token::Match(tok2, "[;}{]"))
break;
if (tok2->str() == "?")
finding = nullptr;
if (Token::Match(tok2, "&&|%oror%"))
finding = tok2;
}
if (finding)
suspiciousCaseInSwitchError(finding, 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("warning") || !_settings->inconclusive)
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)
if (Token::Match(openParen->next(), "%var% =="))
suspiciousEqualityComparisonError(openParen->tokAt(2));
if (Token::Match(closeParen->tokAt(-2), "== %any%"))
suspiciousEqualityComparisonError(closeParen->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++)
if (Token::Match(openParen->next(), "! %var%"))
suspiciousEqualityComparisonError(openParen->next());
if (Token::Match(closeParen->tokAt(-2), "! %var%"))
suspiciousEqualityComparisonError(closeParen->tokAt(-2));
// Skip over for() loop conditions because "for (;running==1;)"
// is a bit strange, but not necessarily incorrect.
tok = closeParen;
} else 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);
}
//---------------------------------------------------------------------------
// 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.
//---------------------------------------------------------------------------
static std::string invertOperatorForOperandSwap(std::string s)
{
if (s[0] == '<')
s[0] = '>';
else if (s[0] == '>')
s[0] = '<';
return s;
}
static bool checkIntRelation(const std::string &op, const MathLib::bigint value1, const MathLib::bigint value2)
{
return (op == "==" && value1 == value2) ||
(op == "!=" && value1 != value2) ||
(op == ">" && value1 > value2) ||
(op == ">=" && value1 >= value2) ||
(op == "<" && value1 < value2) ||
(op == "<=" && value1 <= value2);
}
static bool checkFloatRelation(const std::string &op, const double value1, const double value2)
{
return (op == ">" && value1 > value2) ||
(op == ">=" && value1 >= value2) ||
(op == "<" && value1 < value2) ||
(op == "<=" && value1 <= value2);
}
template<class T> static T getvalue(const int test, const T value1, const T value2)
{
// test:
// 1 => return value that is less than both value1 and value2
// 2 => return value1
// 3 => return value that is between value1 and value2
// 4 => return value2
// 5 => return value that is larger than both value1 and value2
switch (test) {
case 1: {
T ret = std::min(value1, value2);
if ((ret - (T)1) < ret)
return ret - (T)1;
else if ((ret / (T)2) < ret)
return ret / (T)2;
else if ((ret * (T)2) < ret)
return ret * (T)2;
return ret;
}
case 2:
return value1;
case 3:
return (value1 + value2) / (T)2;
case 4:
return value2;
case 5: {
T ret = std::max(value1, value2);
if ((ret + (T)1) > ret)
return ret + (T)1;
else if ((ret / (T)2) > ret)
return ret / (T)2;
else if ((ret * (T)2) > ret)
return ret * (T)2;
return ret;
}
};
return 0;
}
void CheckOther::checkIncorrectLogicOperator()
{
bool style = _settings->isEnabled("style");
bool warning = _settings->isEnabled("warning");
if (!style && !warning)
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()) {
if (Token::Match(tok, "&&|%oror%")) {
// Comparison #1 (LHS)
const Token *comp1 = tok->astOperand1();
if (comp1 && comp1->str() == tok->str())
comp1 = comp1->astOperand2();
// Comparison #2 (RHS)
const Token *comp2 = tok->astOperand2();
if (!comp1 || !comp1->isComparisonOp() || !comp1->astOperand1() || !comp1->astOperand2())
continue;
if (!comp2 || !comp2->isComparisonOp() || !comp2->astOperand1() || !comp2->astOperand2())
continue;
std::string op1, value1;
const Token *expr1;
if (comp1->astOperand1()->isLiteral()) {
op1 = invertOperatorForOperandSwap(comp1->str());
value1 = comp1->astOperand1()->str();
expr1 = comp1->astOperand2();
} else if (comp1->astOperand2()->isLiteral()) {
op1 = comp1->str();
value1 = comp1->astOperand2()->str();
expr1 = comp1->astOperand1();
} else {
continue;
}
std::string op2, value2;
const Token *expr2;
if (comp2->astOperand1()->isLiteral()) {
op2 = invertOperatorForOperandSwap(comp2->str());
value2 = comp2->astOperand1()->str();
expr2 = comp2->astOperand2();
} else if (comp2->astOperand2()->isLiteral()) {
op2 = comp2->str();
value2 = comp2->astOperand2()->str();
expr2 = comp2->astOperand1();
} else {
continue;
}
// Only float and int values are currently handled
if (!MathLib::isInt(value1) && !MathLib::isFloat(value1))
continue;
if (!MathLib::isInt(value2) && !MathLib::isFloat(value2))
continue;
if (isSameExpression(comp1, comp2, _settings->library.functionpure))
continue; // same expressions => only report that there are same expressions
if (!isSameExpression(expr1, expr2, _settings->library.functionpure))
continue;
const bool isfloat = astIsFloat(expr1,true) || MathLib::isFloat(value1) || astIsFloat(expr2,true) || MathLib::isFloat(value2);
// don't check floating point equality comparisons. that is bad
// and deserves different warnings.
if (isfloat && (op1=="==" || op1=="!=" || op2=="==" || op2=="!="))
continue;
// evaluate if expression is always true/false
bool alwaysTrue = true, alwaysFalse = true;
bool firstTrue = true, secondTrue = true;
for (int test = 1; test <= 5; ++test) {
// test:
// 1 => testvalue is less than both value1 and value2
// 2 => testvalue is value1
// 3 => testvalue is between value1 and value2
// 4 => testvalue value2
// 5 => testvalue is larger than both value1 and value2
bool result1, result2;
if (isfloat) {
const double d1 = MathLib::toDoubleNumber(value1);
const double d2 = MathLib::toDoubleNumber(value2);
const double testvalue = getvalue<double>(test, d1, d2);
result1 = checkFloatRelation(op1, testvalue, d1);
result2 = checkFloatRelation(op2, testvalue, d2);
} else {
const MathLib::bigint i1 = MathLib::toLongNumber(value1);
const MathLib::bigint i2 = MathLib::toLongNumber(value2);
const MathLib::bigint testvalue = getvalue<MathLib::bigint>(test, i1, i2);
result1 = checkIntRelation(op1, testvalue, i1);
result2 = checkIntRelation(op2, testvalue, i2);
}
if (tok->str() == "&&") {
alwaysTrue &= (result1 && result2);
alwaysFalse &= !(result1 && result2);
} else {
alwaysTrue &= (result1 || result2);
alwaysFalse &= !(result1 || result2);
}
firstTrue &= !(!result1 && result2);
secondTrue &= !(result1 && !result2);
}
const std::string cond1str = (expr1->isName() ? expr1->str() : "EXPR") + " " + op1 + " " + value1;
const std::string cond2str = (expr2->isName() ? expr2->str() : "EXPR") + " " + op2 + " " + value2;
if (warning && (alwaysTrue || alwaysFalse)) {
const std::string text = cond1str + " " + tok->str() + " " + cond2str;
incorrectLogicOperatorError(tok, text, alwaysTrue);
} else if (style && secondTrue) {
const std::string text = "If " + cond1str + ", the comparison " + cond2str +
" is always " + (secondTrue ? "true" : "false") + ".";
redundantConditionError(tok, text);
} else if (style && firstTrue) {
//const std::string text = "The comparison " + cond1str + " is always " +
// (firstTrue ? "true" : "false") + " when " +
// cond2str + ".";
const std::string text = "If " + cond2str + ", the comparison " + cond1str +
" is always " + (firstTrue ? "true" : "false") + ".";
redundantConditionError(tok, text);
}
}
}
}
}
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()
{
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% ( !!)"))
continue;
const std::string& functionName = tok->str();
int argnr = 1;
const Token *argtok = tok->tokAt(2);
while (argtok && argtok->str() != ")") {
if (Token::Match(argtok,"%num% [,)]")) {
if (MathLib::isInt(argtok->str()) &&
!_settings->library.isargvalid(functionName, argnr, MathLib::toLongNumber(argtok->str())))
invalidFunctionArgError(argtok,functionName,argnr,_settings->library.validarg(functionName,argnr));
} else {
const Token *top = argtok;
while (top->astParent() && top->astParent()->str() != "," && top->astParent() != tok->next())
top = top->astParent();
if (top->isComparisonOp() || Token::Match(top, "%oror%|&&")) {
if (_settings->library.isboolargbad(functionName, argnr))
invalidFunctionArgBoolError(top, functionName, argnr);
// Are the values 0 and 1 valid?
else if (!_settings->library.isargvalid(functionName, argnr, 0))
invalidFunctionArgError(top, functionName, argnr, _settings->library.validarg(functionName,argnr));
else if (!_settings->library.isargvalid(functionName, argnr, 1))
invalidFunctionArgError(top, functionName, argnr, _settings->library.validarg(functionName,argnr));
}
}
argnr++;
argtok = argtok->nextArgument();
}
}
}
// 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 next argument
const Token *tok2 = tok->tokAt(2)->nextArgument();
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 (nullptr != (tok2 = tok2->nextArgument()));
}
}
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.\"");
}
void CheckOther::invalidFunctionArgError(const Token *tok, const std::string &functionName, int argnr, const std::string &validstr)
{
std::ostringstream errmsg;
errmsg << "Invalid " << functionName << "() argument nr " << argnr;
if (!tok)
;
else if (tok->isNumber())
errmsg << ". The value is " << tok->str() << " but the valid values are '" << validstr << "'.";
else if (tok->isComparisonOp())
errmsg << ". The value is 0 or 1 (comparison result) but the valid values are '" << validstr << "'.";
reportError(tok, Severity::error, "invalidFunctionArg", errmsg.str());
}
void CheckOther::invalidFunctionArgBoolError(const Token *tok, const std::string &functionName, int argnr)
{
std::ostringstream errmsg;
errmsg << "Invalid " << functionName << "() argument nr " << argnr << ". A non-boolean value is required.";
reportError(tok, Severity::error, "invalidFunctionArgBool", errmsg.str());
}
//---------------------------------------------------------------------------
// 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->link() && Token::Match(tok, "(|[|<"))
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() == "(")
tok2 = tok2->link();
if (tok2->str() == ";") {
secondBreak = tok2->next();
break;
}
}
} else if (Token::Match(tok, "goto %any% ;")) {
secondBreak = tok->tokAt(3);
labelName = tok->next();
} else if (Token::Match(tok, "%var% (") && _settings->library.isnoreturn(tok->str()) && tok->strAt(-1) != ".") {
if ((!tok->function() || (tok->function()->token != tok && tok->function()->tokenDef != tok)) && tok->linkAt(1)->strAt(1) != "{")
secondBreak = tok->linkAt(1)->tokAt(2);
}
// 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;
tok = tok->previous(); // Will be advanced again by for loop
}
}
}
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)
{
return (var && !var->typeStartToken()->isUnsigned() && Token::Match(var->typeEndToken(), "int|char|short|long") && !var->isPointer() && !var->isArray());
}
void CheckOther::checkUnsignedDivision()
{
bool warning = _settings->isEnabled("warning");
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 && warning && !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("warning"))
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 + " The second and third arguments might be inverted."
" The function memset ( void * ptr, int value, size_t num ) sets the"
" first num bytes of the block of memory pointed by ptr to the specified value.");
reportError(tok, Severity::warning, "memsetZeroBytes", summary + "\n" + verbose);
}
void CheckOther::checkMemsetInvalid2ndParam()
{
const bool portability = _settings->isEnabled("portability");
const bool warning = _settings->isEnabled("warning");
if (!warning && !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->next(); tok && (tok != scope->classEnd); tok = tok->next()) {
if (Token::simpleMatch(tok, "memset (")) {
const Token* firstParamTok = tok->tokAt(2);
if (!firstParamTok)
continue;
const Token* secondParamTok = firstParamTok->nextArgument();
if (!secondParamTok)
continue;
// Second parameter is zero literal, i.e. 0.0f
if (Token::Match(secondParamTok, "%num% ,") && MathLib::isNullValue(secondParamTok->str()))
continue;
const Token *top = secondParamTok;
while (top->astParent() && top->astParent()->str() != ",")
top = top->astParent();
// Check if second parameter is a float variable or a float literal != 0.0f
if (portability && astIsFloat(top,false)) {
memsetFloatError(secondParamTok, top->expressionString());
} else if (warning && secondParamTok->isNumber()) { // Check if the second parameter is a literal and is out of range
const long long int value = MathLib::toLongNumber(secondParamTok->str());
if (value < -128 || value > 255)
memsetValueOutOfRangeError(secondParamTok, secondParamTok->str());
}
}
}
}
}
void CheckOther::memsetFloatError(const Token *tok, const std::string &var_value)
{
const std::string message("The 2nd memset() argument '" + var_value +
"' is a float, its representation is implementation defined.");
const std::string verbose(message + " memset() is used to set each byte of a block of memory to a specific value and"
" the actual representation of a floating-point value is implementation defined.");
reportError(tok, Severity::portability, "memsetFloat", message + "\n" + verbose);
}
void CheckOther::memsetValueOutOfRangeError(const Token *tok, const std::string &value)
{
const std::string message("The 2nd memset() argument '" + value + "' doesn't fit into an 'unsigned char'.");
const std::string verbose(message + " The 2nd parameter is passed as an 'int', but the function fills the block of memory using the 'unsigned char' conversion of this value.");
reportError(tok, Severity::warning, "memsetValueOutOfRange", message + "\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;
if (var->isConst())
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->declarationId())) {
tok = tok->tokAt(3);
if (!tok->isNumber() && tok->type() != Token::eString && tok->type() != Token::eChar && !tok->isBoolean())
continue;
}
bool reduce = true;
bool used = false; // Don't warn about unused variables
for (; tok != var->scope()->classEnd; tok = tok->next()) {
if (tok->str() == "{" && tok->scope() != tok->previous()->scope()) {
if (used) {
bool used2 = false;
if (!checkInnerScope(tok, var, used2) || used2) {
reduce = false;
break;
}
} else if (!checkInnerScope(tok, var, used)) {
reduce = false;
break;
}
tok = tok->link();
// parse else if blocks..
} else if (Token::simpleMatch(tok, "else { if (") && Token::simpleMatch(tok->linkAt(3), ") {")) {
const Token *endif = tok->linkAt(3)->linkAt(1);
bool elseif = false;
if (Token::simpleMatch(endif, "} }"))
elseif = true;
else if (Token::simpleMatch(endif, "} else {") && Token::simpleMatch(endif->linkAt(2),"} }"))
elseif = true;
if (elseif && Token::findmatch(tok->next(), "%varid%", tok->linkAt(1), var->declarationId()))
reduce = false;
} else if (tok->varId() == var->declarationId() || tok->str() == "goto") {
reduce = false;
break;
}
}
if (reduce && used)
variableScopeError(var->nameToken(), var->name());
}
}
bool CheckOther::checkInnerScope(const Token *tok, const Variable* var, bool& used)
{
const Scope* scope = tok->next()->scope();
bool loopVariable = scope->type == Scope::eFor || scope->type == Scope::eWhile || scope->type == Scope::eDo;
bool noContinue = true;
const Token* forHeadEnd = 0;
const Token* end = tok->link();
if (scope->type == Scope::eUnconditional && (tok->strAt(-1) == ")" || tok->previous()->isName())) // Might be an unknown macro like BOOST_FOREACH
loopVariable = true;
if (scope->type == Scope::eDo) {
end = end->linkAt(2);
} else if (loopVariable && tok->strAt(-1) == ")") {
tok = tok->linkAt(-1); // Jump to opening ( of for/while statement
} else if (scope->type == Scope::eSwitch) {
for (std::list<Scope*>::const_iterator i = scope->nestedList.begin(); i != scope->nestedList.end(); ++i) {
if (used) {
bool used2 = false;
if (!checkInnerScope((*i)->classStart, var, used2) || used2) {
return false;
}
} else if (!checkInnerScope((*i)->classStart, var, used)) {
return false;
}
}
}
bool bFirstAssignment=false;
for (; tok != end; tok = tok->next()) {
if (tok->str() == "goto")
return false;
if (tok->str() == "continue")
noContinue = false;
if (Token::simpleMatch(tok, "for ("))
forHeadEnd = tok->linkAt(1);
if (tok == forHeadEnd)
forHeadEnd = 0;
if (loopVariable && noContinue && tok->scope() == scope && !forHeadEnd && scope->type != Scope::eSwitch && Token::Match(tok, "%varid% =", var->declarationId())) { // Assigned in outer scope.
loopVariable = false;
unsigned int indent = 0;
for (const Token* tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) { // Ensure that variable isn't used on right side of =, too
if (tok2->str() == "(")
indent++;
else if (tok2->str() == ")") {
if (indent == 0)
break;
indent--;
} else if (tok2->str() == ";")
break;
else if (tok2->varId() == var->declarationId()) {
loopVariable = true;
break;
}
}
}
if (loopVariable && Token::Match(tok, "%varid% !!=", var->declarationId())) // Variable used in loop
return false;
if (Token::Match(tok, "& %varid%", var->declarationId())) // Taking address of variable
return false;
if (Token::Match(tok, "%varid% = %any%", var->declarationId()))
bFirstAssignment = true;
if (!bFirstAssignment && Token::Match(tok, "* %varid%", var->declarationId())) // dereferencing means access to previous content
return false;
if (Token::Match(tok, "= %varid%", var->declarationId()) && (var->isArray() || var->isPointer())) // Create a copy of array/pointer. Bailout, because the memory it points to might be necessary in outer scope
return false;
if (tok->varId() == var->declarationId()) {
used = true;
if (scope->type == Scope::eSwitch && scope == tok->scope())
return false; // Used in outer switch scope - unsafe or impossible to reduce scope
}
}
return true;
}
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.");
}
void CheckOther::checkCommaSeparatedReturn()
{
// This is experimental for now. See #5076
if (!_settings->experimental)
return;
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->str() == "return") {
while (tok && tok->str() != ";") {
if (Token::Match(tok, "[([{<]") && tok->link())
tok = tok->link();
if (!tok->isExpandedMacro() && tok->str() == "," && tok->linenr() != tok->next()->linenr())
commaSeparatedReturnError(tok);
tok = tok->next();
}
// bailout: missing semicolon (invalid code / bad tokenizer)
if (!tok)
break;
}
}
}
void CheckOther::commaSeparatedReturnError(const Token *tok)
{
reportError(tok,
Severity::style,
"commaSeparatedReturn",
"Comma is used in return statement. The comma can easily be misread as a ';'.\n"
"Comma is used in return statement. When comma is used in a return statement it can "
"easily be misread as a semicolon. For example in the code below the value "
"of 'b' is returned if the condition is true, but it is easy to think that 'a+1' is "
"returned:\n"
" if (x)\n"
" return a + 1,\n"
" b++;\n"
"However it can be useful to use comma in macros. Cppcheck does not warn when such a "
"macro is then used in a return statement, it is less likely such code is misunderstood.");
}
//---------------------------------------------------------------------------
// 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()) { // 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());
}
static bool astIsSignedChar(const Token *tok)
{
if (!tok)
return false;
if (tok->str() == "*" && tok->astOperand1() && !tok->astOperand2()) {
const Variable *var = tok->astOperand1()->variable();
if (!var || !var->isPointer())
return false;
const Token *type = var->typeStartToken();
while (type && type->str() == "const")
type = type->next();
return (type && type->str() == "char" && !type->isUnsigned());
}
return isSignedChar(tok->variable());
}
void CheckOther::checkCharVariable()
{
if (!_settings->isEnabled("warning"))
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% [") && astIsSignedChar(tok->next()->astOperand2())) {
const Variable* arrayvar = tok->variable();
const MathLib::bigint arraysize = (arrayvar && arrayvar->isArray()) ? arrayvar->dimension(0U) : 0;
if (arraysize > 0x80)
charArrayIndexError(tok);
}
else if (Token::Match(tok, "[&|^]")) {
const Token *tok2;
if (tok->astOperand1() && astIsSignedChar(tok->astOperand1()))
tok2 = tok->astOperand2();
else if (tok->astOperand2() && astIsSignedChar(tok->astOperand2()))
tok2 = tok->astOperand1();
else
continue;
// Don't care about address-of operator
if (!tok->astOperand2())
continue;
// it's ok with a bitwise and where the other operand is 0xff or less..
if (tok->str() == "&" && tok2 && tok2->isNumber() && MathLib::isGreater("0x100", tok2->str()))
continue;
// is the result stored in a short|int|long?
if (tok->astParent() && tok->astParent()->str() == "=") {
const Token *eq = tok->astParent();
const Token *lhs = eq->astOperand1();
if (lhs && lhs->str() == "*" && !lhs->astOperand2())
lhs = lhs->astOperand1();
while (lhs && lhs->str() == ".")
lhs = lhs->astOperand2();
if (!lhs || !lhs->isName())
continue;
const Variable *var = lhs->variable();
if (var && Token::Match(var->typeStartToken(), "short|int|long"))
charBitOpError(tok); // 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("warning"))
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();
// C++11 struct/array/etc initialization in initializer list
else if (Token::Match(tok->previous(), "%var% {") && !Token::findsimplematch(tok,";",tok->link()))
tok = tok->link();
// C++11 vector initialization / return { .. }
else if (Token::Match(tok,"> %var% {") || Token::Match(tok, "[;{}] return {"))
tok = tok->linkAt(2);
// C++11 initialize set in initalizer list : [,:] std::set<int>{1} [{,]
else if (Token::simpleMatch(tok,"> {") && tok->link())
tok = tok->next()->link();
else if (Token::Match(tok, "[;{}] %str%|%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;
// no warning if this is the last statement in a ({})
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
if (tok2->str() == "(")
tok2 = tok2->link();
else if (Token::Match(tok2, "[;{}]")) {
bailout = Token::simpleMatch(tok2, "; } )");
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()
{
//_tokenizer->tokens()->printAst(true);
//_tokenizer->tokens()->printOut();
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() == "+") {
if (tok->astOperand1() && (tok->astOperand1()->type() == Token::eString)) { // string literal...
if (tok->astOperand2() && (tok->astOperand2()->type() == Token::eChar || isChar(tok->astOperand2()->variable()))) // added to char variable or char constant
strPlusCharError(tok);
}
}
}
}
}
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, "div|ldiv|lldiv|imaxdiv ( %num% , %num% )") &&
MathLib::isInt(tok->strAt(4)) &&
MathLib::toLongNumber(tok->strAt(4)) == 0L) {
if (tok->str() == "div") {
if (tok->strAt(-1) == ".")
continue;
if (tok->variable() || tok->function())
continue;
}
zerodivError(tok,false);
} else if (Token::Match(tok, "[/%]") && tok->astOperand2()) {
// Value flow..
const ValueFlow::Value *value = tok->astOperand2()->getValue(0LL);
if (value) {
if (!_settings->inconclusive && value->inconclusive)
continue;
if (value->condition == nullptr)
zerodivError(tok, value->inconclusive);
else if (_settings->isEnabled("warning"))
zerodivcondError(value->condition,tok,value->inconclusive);
}
}
}
}
void CheckOther::zerodivError(const Token *tok, bool inconclusive)
{
reportError(tok, Severity::error, "zerodiv", "Division by zero.", inconclusive);
}
void CheckOther::zerodivcondError(const Token *tokcond, const Token *tokdiv, bool inconclusive)
{
std::list<const Token *> callstack;
while (Token::Match(tokcond, "(|%oror%|&&"))
tokcond = tokcond->next();
if (tokcond && tokdiv) {
callstack.push_back(tokcond);
callstack.push_back(tokdiv);
}
std::string condition;
if (!tokcond) {
// getErrorMessages
} else if (Token::Match(tokcond, "%num% <|<=")) {
condition = tokcond->strAt(2) + ((tokcond->strAt(1) == "<") ? ">" : ">=") + tokcond->str();
} else if (tokcond->isComparisonOp()) {
condition = tokcond->expressionString();
} else {
if (tokcond->str() == "!")
condition = tokcond->next()->str() + "==0";
else
condition = tokcond->str() + "!=0";
}
const std::string linenr(MathLib::toString(tokdiv ? tokdiv->linenr() : 0));
reportError(callstack, Severity::warning, "zerodivcond", "Either the condition '"+condition+"' is useless or there is division by zero at line " + linenr + ".", inconclusive);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
/** @brief Check for NaN (not-a-number) in an arithmetic expression
* @note e.g. double d = 1.0 / 0.0 + 100.0;
*/
void CheckOther::checkNanInArithmeticExpression()
{
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "inf.0 +|-") ||
Token::Match(tok, "+|- inf.0") ||
Token::Match(tok, "+|- %num% / 0.0")) {
nanInArithmeticExpressionError(tok);
}
}
}
void CheckOther::nanInArithmeticExpressionError(const Token *tok)
{
reportError(tok, Severity::style, "nanInArithmeticExpression",
"Using NaN/Inf in a computation.\n"
"Using NaN/Inf in a computation. "
"Although nothing bad really happens, it is suspicious.");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
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 (tok->strAt(-1) != "."
&& Token::Match(tok, "log|logf|logl|log10|log10f|log10l ( %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|acosl|acosf|asin|asinf|asinl ( %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|atan2f|atan2l ( %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|fmodf|fmodl ( %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|powf|powl ( %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::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::Match(tok->linkAt(2), ") ; !!}")
&& symbolDatabase->isClassOrStruct(tok->next()->str())
&& (!tok->next()->function() || // is not a function on this scope
(tok->next()->function() && tok->next()->function()->isConstructor()))) { // or is function in this scope and it's a ctor
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.");
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
void CheckOther::checkIncorrectStringCompare()
{
if (!_settings->isEnabled("warning"))
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::simpleMatch(tok, ". substr (") && Token::Match(tok->tokAt(3)->nextArgument(), "%num% )")) {
MathLib::bigint clen = MathLib::toLongNumber(tok->linkAt(2)->strAt(-1));
const Token* begin = tok->previous();
for (;;) { // Find start of statement
while (begin->link() && Token::Match(begin, "]|)|>"))
begin = begin->link()->previous();
if (Token::Match(begin->previous(), ".|::"))
begin = begin->tokAt(-2);
else
break;
}
begin = begin->previous();
const Token* end = tok->linkAt(2)->next();
if (Token::Match(begin->previous(), "%str% ==|!=") && begin->strAt(-2) != "+") {
std::size_t slen = Token::getStrLength(begin->previous());
if (clen != (int)slen) {
incorrectStringCompareError(tok->next(), "substr", begin->strAt(-1));
}
} else if (Token::Match(end, "==|!= %str% !!+")) {
std::size_t slen = Token::getStrLength(end->next());
if (clen != (int)slen) {
incorrectStringCompareError(tok->next(), "substr", end->strAt(1));
}
}
} 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 code in if and else branches
// if (a) { b = true; } else { b = true; }
//-----------------------------------------------------------------------------
void CheckOther::checkDuplicateBranch()
{
// This is inconclusive since in practice most warnings are noise:
// * There can be unfixed low-priority todos. The code is fine as it
// is but it could be possible to enhance it. Writing a warning
// here is noise since the code is fine (see cppcheck, abiword, ..)
// * There can be overspecified code so some conditions can't be true
// and their conditional code is a duplicate of the condition that
// is always true just in case it would be false. See for instance
// abiword.
if (!_settings->isEnabled("style") || !_settings->inconclusive)
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (scope->type != Scope::eIf)
continue;
// check all the code in the function for if (..) else
if (Token::simpleMatch(scope->classEnd, "} else {")) {
// Make sure there are no macros (different macros might be expanded
// to the same code)
bool macro = false;
for (const Token *tok = scope->classStart; tok != scope->classEnd->linkAt(2); tok = tok->next()) {
if (tok->isExpandedMacro()) {
macro = true;
break;
}
}
if (macro)
continue;
// 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<const Token *> 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.", true);
}
//-----------------------------------------------------------------------------
// Check for a free() of an invalid address
// char* p = malloc(100);
// free(p + 10);
//-----------------------------------------------------------------------------
void CheckOther::checkInvalidFree()
{
std::map<unsigned int, bool> 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 varIndex = tok->strAt(1) == "(" ? 2 :
tok->strAt(3) == "(" ? 4 : 1;
const unsigned int var1 = tok->tokAt(varIndex)->varId();
const unsigned int var2 = tok->tokAt(varIndex + 2)->varId();
const std::map<unsigned int, bool>::iterator alloc1 = allocatedVariables.find(var1);
const std::map<unsigned int, bool>::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->next(), "%var%", tok->linkAt(1));
while (tok2 != nullptr) {
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<unsigned int> freedVariables;
std::set<unsigned int> 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% )")) {
const unsigned int varId = tok->tokAt(2)->varId();
if (varId) {
if (Token::Match(tok, "free|g_free")) {
if (freedVariables.find(varId) != freedVariables.end())
doubleFreeError(tok, tok->strAt(2));
else
freedVariables.insert(varId);
} else if (tok->str() == "closedir") {
if (closeDirVariables.find(varId) != closeDirVariables.end())
doubleCloseDirError(tok, tok->strAt(2));
else
closeDirVariables.insert(varId);
}
}
}
// 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% ;")) {
const int varIndex = (tok->strAt(1) == "[") ? 3 : 1;
const unsigned int varId = tok->tokAt(varIndex)->varId();
if (varId) {
if (freedVariables.find(varId) != freedVariables.end())
doubleFreeError(tok, tok->strAt(varIndex));
else
freedVariables.insert(varId);
}
}
// 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()->previous() &&
tok->link()->linkAt(-1) &&
Token::Match(tok->link()->linkAt(-1)->previous(), "while|for") &&
Token::findmatch(tok->link()->linkAt(-1), "break|continue ;", tok) != nullptr) {
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()) {
const unsigned int varId = tok2->varId();
if (varId) {
freedVariables.erase(varId);
closeDirVariables.erase(varId);
}
}
}
}
// If a pointer is assigned a new value, remove it from the set of previously freed variables
else if (Token::Match(tok, "%var% =")) {
const unsigned int varId = tok->varId();
if (varId) {
freedVariables.erase(varId);
closeDirVariables.erase(varId);
}
}
// 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 {
bool notconst(const Function* func)
{
return !func->isConst;
}
void getConstFunctions(const SymbolDatabase *symbolDatabase, std::list<const Function*> &constFunctions)
{
std::list<Scope>::const_iterator scope;
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
std::list<Function>::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<std::string, std::list<const Function*> > 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 Function*>::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);
}
}
}
}
}
//---------------------------------------------------------------------------
// 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)
//---------------------------------------------------------------------------
static bool isWithoutSideEffects(const Tokenizer *tokenizer, const Token* tok)
{
if (!tokenizer->isCPP())
return true;
while (tok && tok->astOperand2() && tok->astOperand2()->str() != "(")
tok = tok->astOperand2();
if (tok->varId()) {
const Variable* var = tok->variable();
return var && (!var->isClass() || var->isPointer() || var->isStlType());
}
return true;
}
void CheckOther::checkDuplicateExpression()
{
if (!_settings->isEnabled("style"))
return;
// Parse all executing scopes..
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
std::list<const Function*> constFunctions;
getConstFunctions(symbolDatabase, constFunctions);
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
// only check functions
if (scope->type != Scope::eFunction)
continue;
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
if (tok->isOp() && tok->astOperand1() && !Token::Match(tok, "+|*|<<|>>")) {
if (Token::Match(tok, "==|!=|-") && astIsFloat(tok->astOperand1(), true))
continue;
if (isSameExpression(tok->astOperand1(), tok->astOperand2(), _settings->library.functionpure)) {
if (isWithoutSideEffects(_tokenizer, tok->astOperand1())) {
const bool assignment = tok->str() == "=";
if (assignment)
selfAssignmentError(tok, tok->astOperand1()->expressionString());
else
duplicateExpressionError(tok, tok, tok->str());
}
} else if (!Token::Match(tok, "[-/%]")) { // These operators are not associative
if (tok->astOperand2() && tok->str() == tok->astOperand1()->str() && isSameExpression(tok->astOperand2(), tok->astOperand1()->astOperand2(), _settings->library.functionpure) && isWithoutSideEffects(_tokenizer, tok->astOperand2()))
duplicateExpressionError(tok->astOperand2(), tok->astOperand2(), tok->str());
else if (tok->astOperand2()) {
const Token *ast1 = tok->astOperand1();
while (ast1 && tok->str() == ast1->str()) {
if (isSameExpression(ast1->astOperand1(), tok->astOperand2(), _settings->library.functionpure) && isWithoutSideEffects(_tokenizer, ast1->astOperand1()))
// TODO: warn if variables are unchanged. See #5683
// Probably the message should be changed to 'duplicate expressions X in condition or something like that'.
;//duplicateExpressionError(ast1->astOperand1(), tok->astOperand2(), tok->str());
else if (isSameExpression(ast1->astOperand2(), tok->astOperand2(), _settings->library.functionpure) && isWithoutSideEffects(_tokenizer, ast1->astOperand2()))
duplicateExpressionError(ast1->astOperand2(), tok->astOperand2(), tok->str());
if (!isConstExpression(ast1->astOperand2(), _settings->library.functionpure))
break;
ast1 = ast1->astOperand1();
}
}
}
}
}
}
}
void CheckOther::duplicateExpressionError(const Token *tok1, const Token *tok2, const std::string &op)
{
std::list<const Token *> 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.");
}
void CheckOther::selfAssignmentError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"selfAssignment", "Redundant assignment of '" + varname + "' to itself.");
}
//---------------------------------------------------------------------------
// Check for string comparison involving two static strings.
// if(strcmp("00FF00","00FF00")==0) // <- statement is always true
//---------------------------------------------------------------------------
void CheckOther::checkAlwaysTrueOrFalseStringCompare()
{
if (!_settings->isEnabled("warning"))
return;
for (const Token* tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "strncmp|strcmp|stricmp|strcmpi|strcasecmp|wcscmp|wcsncmp (")) {
if (Token::Match(tok->tokAt(2), "%str% , %str%")) {
const std::string &str1 = tok->strAt(2);
const std::string &str2 = tok->strAt(4);
alwaysTrueFalseStringCompareError(tok, str1, str2);
tok = tok->tokAt(5);
} else if (Token::Match(tok->tokAt(2), "%var% , %var%")) {
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);
} else if (Token::Match(tok->tokAt(2), "%var% . c_str ( ) , %var% . c_str ( )")) {
const std::string &str1 = tok->strAt(2);
const std::string &str2 = tok->strAt(8);
if (str1 == str2)
alwaysTrueStringVariableCompareError(tok, str1, str2);
tok = tok->tokAt(13);
}
} else if (Token::Match(tok, "QString :: compare ( %str% , %str% )")) {
const std::string &str1 = tok->strAt(4);
const std::string &str2 = tok->strAt(6);
alwaysTrueFalseStringCompareError(tok, str1, str2);
tok = tok->tokAt(7);
} else if (Token::Match(tok, "!!+ %str% ==|!= %str% !!+")) {
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("warning"))
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->type() != Token::eComparisonOp)
continue;
const Token* varTok = tok->astOperand1();
const Token* litTok = tok->astOperand2();
if (!varTok || !litTok) // <- failed to create AST for comparison
continue;
if (varTok->type() == Token::eString || varTok->type() == Token::eNumber)
std::swap(varTok, litTok);
else if (litTok->type() != Token::eString && litTok->type() != Token::eNumber)
continue;
// Pointer addition?
if (varTok->str() == "+" && _tokenizer->isC()) {
const Token *tokens[2] = { varTok->astOperand1(), varTok->astOperand2() };
for (int nr = 0; nr < 2; nr++) {
const Token *t = tokens[nr];
while (t && t->str() == ".")
t = t->astOperand2();
if (t && t->variable() && t->variable()->isPointer())
varTok = t;
}
}
if (varTok->str() == "*") {
if (!_tokenizer->isC() || varTok->astOperand2() != nullptr || litTok->type() != Token::eString)
continue;
varTok = varTok->astOperand1();
}
while (varTok && varTok->str() == ".")
varTok = varTok->astOperand2();
if (!varTok || !varTok->isName())
continue;
const Variable *var = varTok->variable();
while (Token::Match(varTok->astParent(), "[.*]"))
varTok = varTok->astParent();
const std::string varname = varTok->expressionString();
if (litTok->type() == Token::eString) {
if (_tokenizer->isC() || (var && var->isPointer()))
suspiciousStringCompareError(tok, varname);
} else if (litTok->originalName() == "'\\0'" && var && var->isPointer()) {
suspiciousStringCompareError_char(tok, varname);
}
}
}
}
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::suspiciousStringCompareError_char(const Token* tok, const std::string& var)
{
reportError(tok, Severity::warning, "charLiteralWithCharPtrCompare",
"Char literal compared with pointer '" + var + "'. Did you intend to dereference it?");
}
//-----------------------------------------------------------------------------
// Check is a comparison of two variables leads to condition, which is
// always true or false.
// For instance: int a = 1; if(isless(a,a)){...}
// In this case isless(a,a) evaluates always to false.
//
// Reference:
// - http://www.cplusplus.com/reference/cmath/
//-----------------------------------------------------------------------------
void CheckOther::checkComparisonFunctionIsAlwaysTrueOrFalse()
{
if (!_settings->isEnabled("warning"))
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->isName() && Token::Match(tok, "isgreater|isless|islessgreater|isgreaterequal|islessequal ( %var% , %var% )")) {
const unsigned int varidLeft = tok->tokAt(2)->varId();// get the left varid
const unsigned int varidRight = tok->tokAt(4)->varId();// get the right varid
// compare varids: if they are not zero but equal
// --> the comparison function is calles with the same variables
if (varidLeft != 0 && varidLeft == varidRight) {
const std::string& functionName = tok->str(); // store function name
const std::string& varNameLeft = tok->strAt(2); // get the left variable name
if (functionName == "isgreater" || functionName == "isless" || functionName == "islessgreater") {
// e.g.: isgreater(x,x) --> (x)>(x) --> false
checkComparisonFunctionIsAlwaysTrueOrFalseError(tok,functionName,varNameLeft,false);
} else { // functionName == "isgreaterequal" || functionName == "islessequal"
// e.g.: isgreaterequal(x,x) --> (x)>=(x) --> true
checkComparisonFunctionIsAlwaysTrueOrFalseError(tok,functionName,varNameLeft,true);
}
}
}
}
}
}
void CheckOther::checkComparisonFunctionIsAlwaysTrueOrFalseError(const Token* tok, const std::string &functionName, const std::string &varName, const bool result)
{
const std::string strResult = result ? "true" : "false";
reportError(tok, Severity::warning, "comparisonFunctionIsAlwaysTrueOrFalse",
"Comparison of two identical variables with "+functionName+"("+varName+","+varName+") evaluates always to "+strResult+".\n"
"The function "+functionName+" is designed to compare two variables. Calling this function with one variable ("+varName+") "
"for both parameters leads to a statement which is always "+strResult+".");
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
void CheckOther::checkModuloAlwaysTrueFalse()
{
if (!_settings->isEnabled("warning"))
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->isComparisonOp())
continue;
const Token *num,*modulo;
if (Token::simpleMatch(tok->astOperand1(), "%") && Token::Match(tok->astOperand2(), "%num%")) {
modulo = tok->astOperand1();
num = tok->astOperand2();
} else if (Token::Match(tok->astOperand1(), "%num%") && Token::simpleMatch(tok->astOperand2(), "%")) {
num = tok->astOperand1();
modulo = tok->astOperand2();
} else {
continue;
}
if (Token::Match(modulo->astOperand2(), "%num%") &&
MathLib::isLessEqual(modulo->astOperand2()->str(),num->str()))
moduloAlwaysTrueFalseError(tok, modulo->astOperand2()->str());
}
}
}
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 + ".");
}
//-----------------------------------------------------------------------------
// 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 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->tokAt(3), "+|-")) {
// TODO: handle a[10].b , a::b , (unsigned int)x , etc
const Token *prev = tok->previous();
while (prev && (prev->isName() || prev->str() == "."))
prev = prev->previous();
if (!Token::Match(prev, "(|&&|%oror%"))
continue;
const Variable *var = tok->variable();
if (var && var->typeEndToken()->isUnsigned())
unsignedLessThanZeroError(tok, var->name(), inconclusive);
else if (var && (var->isPointer() || var->isArray()))
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);
}
/* check if a constructor in given class scope takes a reference */
static bool constructorTakesReference(const Scope * const classScope)
{
for (std::list<Function>::const_iterator func = classScope->functionList.begin(); func != classScope->functionList.end(); ++func) {
if (func->isConstructor()) {
const Function &constructor = *func;
for (std::size_t argnr = 0U; argnr < constructor.argCount(); argnr++) {
const Variable * const argVar = constructor.getArgumentVar(argnr);
if (argVar && argVar->isReference()) {
return true;
}
}
}
}
return false;
}
/*
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 (std::size_t i = 0; i < symbolDatabase->getVariableListSize(); i++) {
const Variable* var = symbolDatabase->getVariableFromVarId(i);
if (!var || var->isReference() || !var->isConst() || var->isPointer() || (!var->type() && !var->isStlType())) // bailout if var is of standard type, if it is a pointer or non-const
continue;
const Token* startTok = var->nameToken();
if (startTok->strAt(1) == "=") // %type% %var% = ... ;
;
else if (startTok->strAt(1) == "(" && var->isClass() && var->typeScope()) {
// Object is instantiated. Warn if constructor takes arguments by value.
if (constructorTakesReference(var->typeScope()))
continue;
} else
continue;
const Token* tok = startTok->next()->astOperand2();
if (!tok)
continue;
if (!Token::Match(tok->previous(), "%var% ("))
continue;
if (!Token::Match(tok->link(), ") )| ;")) // bailout for usage like "const A a = getA()+3"
continue;
const Function* func = tok->previous()->function();
if (func && func->tokenDef->strAt(-1) == "&") {
redundantCopyError(startTok, startTok->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.",
true); // since #5618 that check became inconlusive
}
//---------------------------------------------------------------------------
// 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 (tok->str() != "<<" && tok->str() != ">>")
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
// don't warn if lhs is a class. this is an overloaded operator then
if (_tokenizer->isCPP()) {
const Token *rhs = tok->astOperand1();
while (Token::Match(rhs, "::|."))
rhs = rhs->astOperand2();
if (!rhs)
continue;
if (!rhs->isNumber() && !rhs->variable())
continue;
if (rhs->variable() &&
(!rhs->variable()->typeStartToken() || !rhs->variable()->typeStartToken()->isStandardType()))
continue;
}
// Get negative rhs value. preferably a value which doesn't have 'condition'.
const ValueFlow::Value *value = tok->astOperand2()->getValueLE(-1LL, _settings);
if (value)
negativeBitwiseShiftError(tok);
}
}
}
void CheckOther::negativeBitwiseShiftError(const Token *tok)
{
reportError(tok, Severity::error, "shiftNegative", "Shifting by a negative value is undefined behaviour");
}
//---------------------------------------------------------------------------
// Check for incompletely filled buffers.
//---------------------------------------------------------------------------
void CheckOther::checkIncompleteArrayFill()
{
bool warning = _settings->isEnabled("warning");
bool portability = _settings->isEnabled("portability");
if (!_settings->inconclusive || (!portability && !warning))
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->isPointer()) {
if (warning)
incompleteArrayFillError(tok, var->name(), tok->str(), false);
} else if (var->typeStartToken()->str() == "bool" && 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()
{
if (!_settings->isEnabled("warning"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (scope->type != Scope::eIf)
continue;
if (!Token::simpleMatch(scope->classDef->linkAt(1), ") {"))
continue;
bool nonlocal = false; // nonlocal variable used in condition
std::set<unsigned int> vars; // variables used in condition
for (const Token *cond = scope->classDef; cond != scope->classDef->linkAt(1); cond = cond->next()) {
if (cond->varId()) {
vars.insert(cond->varId());
const Variable *var = cond->variable();
nonlocal |= (var && (!var->isLocal() || var->isStatic()) && !var->isArgument());
// TODO: if var is pointer check what it points at
nonlocal |= (var && (var->isPointer() || var->isReference()));
} else if (cond->isName()) {
// varid is 0. this is possibly a nonlocal variable..
nonlocal |= (cond->astParent() && cond->astParent()->isConstOp());
}
}
// parse until inner condition is reached..
const Token *ifToken = nullptr;
for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
if (Token::simpleMatch(tok, "if (")) {
ifToken = tok;
break;
}
if (Token::Match(tok,"%type% (") && nonlocal) // function call -> bailout if there are nonlocal variables
break;
else if ((tok->varId() && vars.find(tok->varId()) != vars.end()) ||
(!tok->varId() && nonlocal)) {
if (Token::Match(tok, "%var% ++|--|="))
break;
if (Token::Match(tok,"%var% [")) {
const Token *tok2 = tok->linkAt(1);
while (Token::simpleMatch(tok2, "] ["))
tok2 = tok2->linkAt(1);
if (Token::simpleMatch(tok2, "] ="))
break;
}
if (Token::Match(tok->previous(), "++|--|& %var%"))
break;
if (Token::Match(tok->previous(), "[(,] %var% [,)]")) {
// is variable unchanged? default is false..
bool unchanged = false;
// locate start parentheses in function call..
unsigned int argumentNumber = 0;
const Token *start = tok->previous();
while (start && start->str() == ",") {
start = start->astParent();
++argumentNumber;
}
start = start ? start->previous() : nullptr;
if (start && start->function()) {
const Variable *arg = start->function()->getArgumentVar(argumentNumber);
if (arg && !arg->isPointer() && !arg->isReference())
unchanged = true;
}
if (!unchanged)
break;
}
}
}
if (!ifToken)
continue;
// Condition..
const Token *cond1 = scope->classDef->next()->astOperand2();
const Token *cond2 = ifToken->next()->astOperand2();
if (isOppositeCond(cond1, cond2, _settings->library.functionpure))
oppositeInnerConditionError(scope->classDef, cond2);
}
}
void CheckOther::oppositeInnerConditionError(const Token *tok1, const Token* tok2)
{
std::list<const Token*> callstack;
callstack.push_back(tok1);
callstack.push_back(tok2);
reportError(callstack, Severity::warning, "oppositeInnerCondition", "Opposite conditions in nested 'if' blocks lead to a dead code block.");
}
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() : nullptr;
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() : nullptr; // 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 <stdarg.h>\n"
"#include <stdio.h>\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<sizeof(a); i++)\n"
" a[i] = -1;\n"
"}\n"
"\n"
"int main() {\n"
" h();\n"
" g();\n"
" return 0;\n"
"}");
}
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