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minor tweak of comment

This commit is contained in:
Daniel Marjamäki 2015-12-14 20:03:40 +01:00
parent 2532f94bef
commit b1d1869f22
5 changed files with 232 additions and 1 deletions
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2
addons/cppcheckdata.py
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@ -352,7 +352,7 @@ class ValueFlow:
# http://cppcheck.sourceforge.net/devinfo/doxyoutput/classValueFlow_1_1Value.html
class Value:
# #integer value
## integer value
intvalue = None
## token value
tokvalue = None

45
lib/astutils.cpp
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@ -239,6 +239,51 @@ bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token
(comp1 == ">" && comp2 == "<"))));
}
bool isIncorrectCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions)
{
if (!cond1 || !cond2)
return false;
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 isIncorrectCond(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 incorrect?
return ((comp1 == "<" && comp2 == "==") ||
(comp1 == ">" && comp2 == "==") ||
(comp1 == "==" && comp2 == "<") ||
(comp1 == "==" && comp2 == ">"));
}
bool isConstExpression(const Token *tok, const std::set<std::string> &constFunctions)
{
if (!tok)

1
lib/astutils.h
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@ -59,6 +59,7 @@ bool isSameExpression(bool cpp, const Token *tok1, const Token *tok2, const std:
* @param constFunctions constFunctions
*/
bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions);
bool isIncorrectCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions);
bool isConstExpression(const Token *tok, const std::set<std::string> &constFunctions);

182
lib/checkcondition.cpp
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@ -641,6 +641,187 @@ static std::string conditionString(bool not1, const Token *expr1, const std::str
(expr1->isName() ? expr1->str() : std::string("EXPR"));
}
void CheckCondition::checkIncorrectCondition()
{
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()) &&
isIncorrectCond(true, _tokenizer->isCPP(), tok->astOperand1(), tok->astOperand2(), _settings->library.functionpure)) {
const bool alwaysTrue(tok->str() == "||");
incorrectConditionError(tok, tok->expressionString(), alwaysTrue);
continue;
}
// 'A && (!A || B)' is equivalent with 'A && B'
// 'A || (!A && B)' is equivalent with 'A || B'
if (printStyle &&
((tok->str() == "||" && tok->astOperand2()->str() == "&&") ||
(tok->str() == "&&" && tok->astOperand2()->str() == "||"))) {
const Token* tok2 = tok->astOperand2()->astOperand1();
if (isIncorrectCond(true, _tokenizer->isCPP(), tok->astOperand1(), tok2, _settings->library.functionpure)) {
std::string expr1(tok->astOperand1()->expressionString());
std::string expr2(tok->astOperand2()->astOperand1()->expressionString());
std::string expr3(tok->astOperand2()->astOperand2()->expressionString());
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;
redundantConditionError(tok, tok2->expressionString() + ". '" + cond1 + "' is equivalent to '" + cond2 + "'");
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, &not1, &op1, &value1, &expr1))
continue;
// Parse RHS
bool not2;
std::string op2, value2;
const Token *expr2;
if (!parseComparison(comp2, &not2, &op2, &value2, &expr2))
continue;
if (isSameExpression(_tokenizer->isCPP(), comp1, comp2, _settings->library.functionpure))
continue; // same expressions => only report that there are same expressions
if (!isSameExpression(_tokenizer->isCPP(), expr1, expr2, _settings->library.functionpure)) {
if ((tok->astOperand1()->isConstOp() && tok->astOperand2()->isConstOp()) &&
isIncorrectCond(true, _tokenizer->isCPP(), tok->astOperand1(), tok->astOperand2(), _settings->library.functionpure)) {
const bool alwaysTrue(tok->str() == "||");
incorrectConditionError(tok, tok->expressionString(), alwaysTrue);
}
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;
incorrectConditionError(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::incorrectConditionError(const Token *tok, const std::string &condition, bool always)
{
if (always)
reportError(tok, Severity::warning, "IncorrectCondition",
"Condition always evaluates to true: " + condition + ".\n"
"Condition 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, "IncorrectCondition",
"Condition always evaluates to false: " + condition + ".\n"
"Condition 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 CheckCondition::checkIncorrectLogicOperator()
{
const bool printStyle = _settings->isEnabled("style");
@ -813,6 +994,7 @@ void CheckCondition::incorrectLogicOperatorError(const Token *tok, const std::st
"Are these conditions necessary? Did you intend to use || instead? Are the numbers correct? Are you comparing the correct variables?");
}
void CheckCondition::redundantConditionError(const Token *tok, const std::string &text)
{
reportError(tok, Severity::style, "redundantCondition", "Redundant condition: " + text);

3
lib/checkcondition.h
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@ -50,6 +50,7 @@ public:
checkCondition.clarifyCondition(); // not simplified because ifAssign
checkCondition.oppositeInnerCondition();
checkCondition.checkIncorrectLogicOperator();
checkCondition.checkIncorrectCondition();
checkCondition.checkInvalidTestForOverflow();
}
@ -88,6 +89,7 @@ public:
/** @brief %Check for testing for mutual exclusion over ||*/
void checkIncorrectLogicOperator();
void checkIncorrectCondition();
/** @brief %Check for suspicious usage of modulo (e.g. "if(var % 4 == 4)") */
void checkModuloAlwaysTrueFalse();
@ -118,6 +120,7 @@ private:
void oppositeInnerConditionError(const Token *tok1, const Token* tok2);
void incorrectLogicOperatorError(const Token *tok, const std::string &condition, bool always);
void incorrectConditionError(const Token *tok, const std::string &condition, bool always);
void redundantConditionError(const Token *tok, const std::string &text);
void moduloAlwaysTrueFalseError(const Token* tok, const std::string& maxVal);