bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions, bool isStrict)
{
if (!cond1 || !cond2)
return false;
//handle if(NULL == pstReply) { if(pstReply){ a=3;}}
if (Token::Match(cond1, "== 0|nullptr") && !Token::Match(cond2, "==|!="))
{
return isSameExpression(cpp, cond1->astOperand1(), cond2, constFunctions);
}
if (Token::Match(cond1->tokAt(-1), "0|nullptr ==") && !Token::Match(cond2, "==|!="))
{
return isSameExpression(cpp, cond1->astOperand2(), cond2, constFunctions);
}
if (cond1->str() == "!") {
if (cond2->str() == "!=") {
if (cond2->astOperand1() && cond2->astOperand1()->str() == "0")
return isSameExpression(cpp, cond1->astOperand1(), cond2->astOperand2(), constFunctions);
if (cond2->astOperand2() && cond2->astOperand2()->str() == "0")
return isSameExpression(cpp, cond1->astOperand1(), cond2->astOperand1(), constFunctions);
}
return isSameExpression(cpp, cond1->astOperand1(), cond2, constFunctions);
}
if (cond2->str() == "!")
return isOppositeCond(isNot, cpp, cond2, cond1, constFunctions);
if (!cond1->isComparisonOp() || !cond2->isComparisonOp())
return false;
const std::string &comp1 = cond1->str();
// condition found .. get comparator
std::string comp2;
if (isSameExpression(cpp, cond1->astOperand1(), cond2->astOperand1(), constFunctions) &&
isSameExpression(cpp, cond1->astOperand2(), cond2->astOperand2(), constFunctions)) {
comp2 = cond2->str();
}
else if (isSameExpression(cpp, cond1->astOperand1(), cond2->astOperand2(), constFunctions) &&
isSameExpression(cpp, 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 == "<") ||
(!isNot && ((comp1 == "<" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<"))) ||
(!isStrict && ((comp1 == "<=" && comp2 == ">=") || (comp1 == ">=" && comp2 == "<="))));
}
bool isOppositeExpression(bool cpp, const Token * const tok1, const Token * const tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors)
{
if (!tok1 || !tok2)
return false;
if (isOppositeCond(true, cpp, tok1, tok2, library, pure, followVar, errors))
return true;
if (tok1->isUnaryOp("-"))
return isSameExpression(cpp, true, tok1->astOperand1(), tok2, library, pure, followVar, errors);
if (tok2->isUnaryOp("-"))
return isSameExpression(cpp, true, tok2->astOperand1(), tok1, library, pure, followVar, errors);
return false;
}
bool CheckCondition::isOppositeCond(bool isNot, const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions) const
{
if (!cond1 || !cond2)
return false;
if (cond1->str() == "!") {
if (cond2->str() == "!=") {
if (cond2->astOperand1()->str() == "0")
return isSameExpression(_tokenizer, cond1->astOperand1(), cond2->astOperand2(), constFunctions);
if (cond2->astOperand2()->str() == "0")
return isSameExpression(_tokenizer, cond1->astOperand1(), cond2->astOperand1(), constFunctions);
}
return isSameExpression(_tokenizer, cond1->astOperand1(), cond2, constFunctions);
}
if (cond2->str() == "!")
return isOppositeCond(isNot, cond2, cond1, constFunctions);
if (!cond1->isComparisonOp() || !cond2->isComparisonOp())
return false;
const std::string &comp1 = cond1->str();
// condition found .. get comparator
std::string comp2;
if (isSameExpression(_tokenizer, cond1->astOperand1(), cond2->astOperand1(), constFunctions) &&
isSameExpression(_tokenizer, cond1->astOperand2(), cond2->astOperand2(), constFunctions)) {
comp2 = cond2->str();
} else if (isSameExpression(_tokenizer, cond1->astOperand1(), cond2->astOperand2(), constFunctions) &&
isSameExpression(_tokenizer, 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 == "<") ||
(!isNot && ((comp1 == "<" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<"))));
}
void CheckCondition::checkIncorrectLogicOperator()
{
const bool printStyle = _settings->isEnabled("style");
const bool printWarning = _settings->isEnabled("warning");
if (!printWarning && !printStyle)
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%|&&") || !tok->astOperand1() || !tok->astOperand2())
continue;
// Opposite comparisons around || or && => always true or always false
if ((tok->astOperand1()->isName() || tok->astOperand2()->isName()) &&
isOppositeCond(true, tok->astOperand1(), tok->astOperand2(), _settings->library.functionpure)) {
const bool alwaysTrue(tok->str() == "||");
incorrectLogicOperatorError(tok, tok->expressionString(), alwaysTrue);
continue;
}
// 'A && (!A || B)' is equivalent with 'A || B'
if (printStyle && (tok->str() == "||") && tok->astOperand1() && tok->astOperand2() && tok->astOperand2()->str() == "&&") {
const Token* tok2 = tok->astOperand2()->astOperand1();
if (isOppositeCond(true, tok->astOperand1(), tok2, _settings->library.functionpure)) {
redundantConditionError(tok, tok2->expressionString() + ". 'A && (!A || B)' is equivalent to 'A || B'");
continue;
}
}
// 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();
// Parse LHS
bool not1;
std::string op1, value1;
const Token *expr1;
if (!parseComparison(comp1, ¬1, &op1, &value1, &expr1))
continue;
// Parse RHS
bool not2;
std::string op2, value2;
const Token *expr2;
if (!parseComparison(comp2, ¬2, &op2, &value2, &expr2))
continue;
if (isSameExpression(_tokenizer, comp1, comp2, _settings->library.functionpure))
continue; // same expressions => only report that there are same expressions
if (!isSameExpression(_tokenizer, 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;
const double d1 = (isfloat) ? MathLib::toDoubleNumber(value1) : 0;
const double d2 = (isfloat) ? MathLib::toDoubleNumber(value2) : 0;
const MathLib::bigint i1 = (isfloat) ? 0 : MathLib::toLongNumber(value1);
const MathLib::bigint i2 = (isfloat) ? 0 : MathLib::toLongNumber(value2);
const bool useUnsignedInt = (std::numeric_limits<MathLib::bigint>::max()==i1)||(std::numeric_limits<MathLib::bigint>::max()==i2);
const MathLib::biguint u1 = (useUnsignedInt) ? MathLib::toLongNumber(value1) : 0;
const MathLib::biguint u2 = (useUnsignedInt) ? MathLib::toLongNumber(value2) : 0;
// 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 testvalue = getvalue<double>(test, d1, d2);
result1 = checkFloatRelation(op1, testvalue, d1);
result2 = checkFloatRelation(op2, testvalue, d2);
} else if (useUnsignedInt) {
const MathLib::biguint testvalue = getvalue<MathLib::biguint>(test, u1, u2);
result1 = checkIntRelation(op1, testvalue, u1);
result2 = checkIntRelation(op2, testvalue, u2);
} else {
const MathLib::bigint testvalue = getvalue<MathLib::bigint>(test, i1, i2);
result1 = checkIntRelation(op1, testvalue, i1);
result2 = checkIntRelation(op2, testvalue, i2);
}
if (not1)
result1 = !result1;
if (not2)
result2 = !result2;
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 = conditionString(not1, expr1, op1, value1);
const std::string cond2str = conditionString(not2, expr2, op2, value2);
if (printWarning && (alwaysTrue || alwaysFalse)) {
const std::string text = cond1str + " " + tok->str() + " " + cond2str;
incorrectLogicOperatorError(tok, text, alwaysTrue);
} else if (printStyle && secondTrue) {
const std::string text = "If " + cond1str + ", the comparison " + cond2str +
" is always " + (secondTrue ? "true" : "false") + ".";
redundantConditionError(tok, text);
} else if (printStyle && 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 CheckCondition::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->linkAt(1); cond != scope->classDef; cond = cond->previous()) {
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 |= Token::Match(cond->astParent(), "%cop%|(");
}
}
// 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, "%name% ++|--|="))
break;
if (Token::Match(tok, "%name% [")) {
const Token *tok2 = tok->linkAt(1);
while (Token::simpleMatch(tok2, "] ["))
tok2 = tok2->linkAt(1);
if (Token::simpleMatch(tok2, "] ="))
break;
}
if (Token::Match(tok->previous(), "++|--|& %name%"))
break;
if (tok->variable() &&
Token::Match(tok, "%name% . %name% (") &&
!tok->variable()->isConst()) {
const Function* function = tok->tokAt(2)->function();
if (!function || !function->isConst())
break;
}
if (Token::Match(tok->previous(), "[(,] %name% [,)]")) {
// 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(false, cond1, cond2, _settings->library.functionpure))
oppositeInnerConditionError(scope->classDef, cond2);
}
}
void CheckCondition::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()) {
// Opposite comparisons
if (Token::Match(tok, "%oror%|&&") &&
tok->astOperand1() &&
tok->astOperand2() &&
(tok->astOperand1()->isName() || tok->astOperand2()->isName()) &&
isOppositeCond(tok->astOperand1(), tok->astOperand2(), _settings->library.functionpure)) {
const bool alwaysTrue(tok->str() == "||");
incorrectLogicOperatorError(tok, tok->expressionString(), alwaysTrue);
}
else 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);
}
}
}
}
}
bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const Library& library, bool pure, bool followVar, ErrorPath* errors)
{
if (!cond1 || !cond2)
return false;
if (cond1->str() == "!") {
if (cond2->str() == "!=") {
if (cond2->astOperand1() && cond2->astOperand1()->str() == "0")
return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), library, pure, followVar, errors);
if (cond2->astOperand2() && cond2->astOperand2()->str() == "0")
return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors);
}
return isSameExpression(cpp, true, cond1->astOperand1(), cond2, library, pure, followVar, errors);
}
if (cond2->str() == "!")
return isOppositeCond(isNot, cpp, cond2, cond1, library, pure, followVar, errors);
if (!isNot) {
if (cond1->str() == "==" && cond2->str() == "==") {
if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors))
return isDifferentKnownValues(cond1->astOperand2(), cond2->astOperand2());
if (isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), library, pure, followVar, errors))
return isDifferentKnownValues(cond1->astOperand1(), cond2->astOperand1());
}
// TODO: Handle reverse conditions
if (Library::isContainerYield(cond1, Library::Container::EMPTY, "empty") &&
Library::isContainerYield(cond2->astOperand1(), Library::Container::SIZE, "size") &&
cond1->astOperand1()->astOperand1()->varId() == cond2->astOperand1()->astOperand1()->astOperand1()->varId()) {
return !isZeroBoundCond(cond2);
}
if (Library::isContainerYield(cond2, Library::Container::EMPTY, "empty") &&
Library::isContainerYield(cond1->astOperand1(), Library::Container::SIZE, "size") &&
cond2->astOperand1()->astOperand1()->varId() == cond1->astOperand1()->astOperand1()->astOperand1()->varId()) {
return !isZeroBoundCond(cond1);
}
}
if (!cond1->isComparisonOp() || !cond2->isComparisonOp())
return false;
const std::string &comp1 = cond1->str();
// condition found .. get comparator
std::string comp2;
if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors) &&
isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), library, pure, followVar, errors)) {
comp2 = cond2->str();
} else if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), library, pure, followVar, errors) &&
isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand1(), library, pure, followVar, errors)) {
comp2 = cond2->str();
if (comp2[0] == '>')
comp2[0] = '<';
else if (comp2[0] == '<')
comp2[0] = '>';
}
if (!isNot && comp2.empty()) {
const Token *expr1 = nullptr, *value1 = nullptr, *expr2 = nullptr, *value2 = nullptr;
std::string op1 = cond1->str(), op2 = cond2->str();
if (cond1->astOperand2()->hasKnownIntValue()) {
expr1 = cond1->astOperand1();
value1 = cond1->astOperand2();
} else if (cond1->astOperand1()->hasKnownIntValue()) {
expr1 = cond1->astOperand2();
value1 = cond1->astOperand1();
if (op1[0] == '>')
op1[0] = '<';
else if (op1[0] == '<')
op1[0] = '>';
}
if (cond2->astOperand2()->hasKnownIntValue()) {
expr2 = cond2->astOperand1();
value2 = cond2->astOperand2();
} else if (cond2->astOperand1()->hasKnownIntValue()) {
expr2 = cond2->astOperand2();
value2 = cond2->astOperand1();
if (op2[0] == '>')
op2[0] = '<';
else if (op2[0] == '<')
op2[0] = '>';
}
if (!expr1 || !value1 || !expr2 || !value2) {
return false;
}
if (!isSameExpression(cpp, true, expr1, expr2, library, pure, followVar, errors))
return false;
const ValueFlow::Value &rhsValue1 = value1->values().front();
const ValueFlow::Value &rhsValue2 = value2->values().front();
if (op1 == "<" || op1 == "<=")
return (op2 == "==" || op2 == ">" || op2 == ">=") && (rhsValue1.intvalue < rhsValue2.intvalue);
else if (op1 == ">=" || op1 == ">")
return (op2 == "==" || op2 == "<" || op2 == "<=") && (rhsValue1.intvalue > rhsValue2.intvalue);
return false;
}
// is condition opposite?
return ((comp1 == "==" && comp2 == "!=") ||
(comp1 == "!=" && comp2 == "==") ||
(comp1 == "<" && comp2 == ">=") ||
(comp1 == "<=" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<=") ||
(comp1 == ">=" && comp2 == "<") ||
(!isNot && ((comp1 == "<" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<") ||
(comp1 == "==" && (comp2 == "!=" || comp2 == ">" || comp2 == "<")) ||
((comp1 == "!=" || comp1 == ">" || comp1 == "<") && comp2 == "==")
)));
}
void CheckCondition::checkIncorrectLogicOperator()
{
const bool printStyle = _settings->isEnabled(Settings::STYLE);
const bool printWarning = _settings->isEnabled(Settings::WARNING);
if (!printWarning && !printStyle)
return;
const bool printInconclusive = _settings->inconclusive;
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%|&&") || !tok->astOperand1() || !tok->astOperand2())
continue;
// Opposite comparisons around || or && => always true or always false
if ((tok->astOperand1()->isName() || tok->astOperand2()->isName()) &&
isOppositeCond(true, _tokenizer->isCPP(), tok->astOperand1(), tok->astOperand2(), _settings->library, true)) {
const bool alwaysTrue(tok->str() == "||");
incorrectLogicOperatorError(tok, tok->expressionString(), alwaysTrue, false);
continue;
}
// 'A && (!A || B)' is equivalent to 'A && B'
// 'A || (!A && B)' is equivalent to 'A || B'
if (printStyle &&
((tok->str() == "||" && tok->astOperand2()->str() == "&&") ||
(tok->str() == "&&" && tok->astOperand2()->str() == "||"))) {
const Token* tok2 = tok->astOperand2()->astOperand1();
if (isOppositeCond(true, _tokenizer->isCPP(), tok->astOperand1(), tok2, _settings->library, true)) {
std::string expr1(tok->astOperand1()->expressionString());
std::string expr2(tok->astOperand2()->astOperand1()->expressionString());
std::string expr3(tok->astOperand2()->astOperand2()->expressionString());
// make copy for later because the original string might get overwritten
const std::string expr1VerboseMsg = expr1;
const std::string expr2VerboseMsg = expr2;
const std::string expr3VerboseMsg = expr3;
if (expr1.length() + expr2.length() + expr3.length() > 50U) {
if (expr1[0] == '!' && expr2[0] != '!') {
expr1 = "!A";
expr2 = "A";
} else {
expr1 = "A";
expr2 = "!A";
}
expr3 = "B";
}
const std::string cond1 = expr1 + " " + tok->str() + " (" + expr2 + " " + tok->astOperand2()->str() + " " + expr3 + ")";
const std::string cond2 = expr1 + " " + tok->str() + " " + expr3;
const std::string cond1VerboseMsg = expr1VerboseMsg + " " + tok->str() + " " + expr2VerboseMsg + " " + tok->astOperand2()->str() + " " + expr3VerboseMsg;
const std::string cond2VerboseMsg = expr1VerboseMsg + " " + tok->str() + " " + expr3VerboseMsg;
// for the --verbose message, transform the actual condition and print it
const std::string msg = tok2->expressionString() + ". '" + cond1 + "' is equivalent to '" + cond2 + "'\n"
"The condition '" + cond1VerboseMsg + "' is equivalent to '" + cond2VerboseMsg + "'.";
redundantConditionError(tok, msg, false);
continue;
}
}
// 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();
bool inconclusive = false;
// Parse LHS
bool not1;
std::string op1, value1;
const Token *expr1;
if (!parseComparison(comp1, ¬1, &op1, &value1, &expr1, &inconclusive))
continue;
// Parse RHS
bool not2;
std::string op2, value2;
const Token *expr2;
if (!parseComparison(comp2, ¬2, &op2, &value2, &expr2, &inconclusive))
continue;
if (inconclusive && !printInconclusive)
continue;
if (isSameExpression(_tokenizer->isCPP(), true, comp1, comp2, _settings->library, true))
continue; // same expressions => only report that there are same expressions
if (!isSameExpression(_tokenizer->isCPP(), true, expr1, expr2, _settings->library, true))
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;
const double d1 = (isfloat) ? MathLib::toDoubleNumber(value1) : 0;
const double d2 = (isfloat) ? MathLib::toDoubleNumber(value2) : 0;
const MathLib::bigint i1 = (isfloat) ? 0 : MathLib::toLongNumber(value1);
const MathLib::bigint i2 = (isfloat) ? 0 : MathLib::toLongNumber(value2);
const bool useUnsignedInt = (std::numeric_limits<MathLib::bigint>::max()==i1)||(std::numeric_limits<MathLib::bigint>::max()==i2);
const MathLib::biguint u1 = (useUnsignedInt) ? MathLib::toLongNumber(value1) : 0;
const MathLib::biguint u2 = (useUnsignedInt) ? MathLib::toLongNumber(value2) : 0;
// 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 testvalue = getvalue<double>(test, d1, d2);
result1 = checkFloatRelation(op1, testvalue, d1);
result2 = checkFloatRelation(op2, testvalue, d2);
} else if (useUnsignedInt) {
const MathLib::biguint testvalue = getvalue<MathLib::biguint>(test, u1, u2);
result1 = checkIntRelation(op1, testvalue, u1);
result2 = checkIntRelation(op2, testvalue, u2);
} else {
const MathLib::bigint testvalue = getvalue<MathLib::bigint>(test, i1, i2);
result1 = checkIntRelation(op1, testvalue, i1);
result2 = checkIntRelation(op2, testvalue, i2);
}
if (not1)
result1 = !result1;
if (not2)
result2 = !result2;
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 = conditionString(not1, expr1, op1, value1);
const std::string cond2str = conditionString(not2, expr2, op2, value2);
if (printWarning && (alwaysTrue || alwaysFalse)) {
const std::string text = cond1str + " " + tok->str() + " " + cond2str;
incorrectLogicOperatorError(tok, text, alwaysTrue, inconclusive);
} else if (printStyle && secondTrue) {
const std::string text = "If '" + cond1str + "', the comparison '" + cond2str +
"' is always " + (secondTrue ? "true" : "false") + ".";
redundantConditionError(tok, text, inconclusive);
} else if (printStyle && 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, inconclusive);
}
}
}
}
void CheckCondition::oppositeInnerCondition()
{
if (!_settings->isEnabled(Settings::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->linkAt(1); cond != scope->classDef; cond = cond->previous()) {
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 (!nonlocal && cond->isName()) {
// varid is 0. this is possibly a nonlocal variable..
nonlocal = Token::Match(cond->astParent(), "%cop%|(");
}
}
// 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;
// bailout if loop is seen.
// TODO: handle loops.
if (Token::Match(tok, "for|while|do"))
break;
if ((tok->varId() && vars.find(tok->varId()) != vars.end()) ||
(!tok->varId() && nonlocal)) {
if (Token::Match(tok, "%name% %assign%|++|--"))
break;
if (Token::Match(tok, "%name% [")) {
const Token *tok2 = tok->linkAt(1);
while (Token::simpleMatch(tok2, "] ["))
tok2 = tok2->linkAt(1);
if (Token::Match(tok2, "] %assign%|++|--"))
break;
}
if (Token::Match(tok->previous(), "++|--|& %name%"))
break;
if (tok->variable() &&
!tok->variable()->isConst() &&
Token::Match(tok, "%name% . %name% (")) {
const Function* function = tok->tokAt(2)->function();
if (!function || !function->isConst())
break;
}
if (Token::Match(tok->previous(), "[(,] %name% [,)]") && isParameterChanged(tok))
break;
}
}
if (!ifToken)
continue;
// Condition..
const Token *cond1 = scope->classDef->next()->astOperand2();
const Token *cond2 = ifToken->next()->astOperand2();
if (isOppositeCond(false, _tokenizer->isCPP(), cond1, cond2, _settings->library, true))
oppositeInnerConditionError(scope->classDef, cond2);
}
}
