cppcheck/lib/checkcondition.h

186 lines
7.4 KiB
C++

/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2016 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/>.
*/
//---------------------------------------------------------------------------
#ifndef checkconditionH
#define checkconditionH
//---------------------------------------------------------------------------
#include "check.h"
#include "config.h"
#include "mathlib.h"
#include <string>
class ErrorLogger;
class Settings;
class Token;
class Tokenizer;
/// @addtogroup Checks
/// @{
/**
* @brief Check for condition mismatches
*/
class CPPCHECKLIB CheckCondition : public Check {
public:
/** This constructor is used when registering the CheckAssignIf */
CheckCondition() : Check(myName()) {
}
/** This constructor is used when running checks. */
CheckCondition(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
: Check(myName(), tokenizer, settings, errorLogger) {
}
void runChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) {
CheckCondition checkCondition(tokenizer, settings, errorLogger);
checkCondition.multiCondition();
checkCondition.clarifyCondition(); // not simplified because ifAssign
checkCondition.multiCondition2();
checkCondition.checkIncorrectLogicOperator();
checkCondition.checkInvalidTestForOverflow();
checkCondition.alwaysTrueFalse();
}
/** @brief Run checks against the simplified token list */
void runSimplifiedChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) {
CheckCondition checkCondition(tokenizer, settings, errorLogger);
checkCondition.assignIf();
checkCondition.checkBadBitmaskCheck();
checkCondition.comparison();
checkCondition.checkModuloAlwaysTrueFalse();
}
/** mismatching assignment / comparison */
void assignIf();
/** parse scopes recursively */
bool assignIfParseScope(const Token * const assignTok,
const Token * const startTok,
const unsigned int varid,
const bool islocal,
const char bitop,
const MathLib::bigint num);
/** check bitmask using | instead of & */
void checkBadBitmaskCheck();
/** mismatching lhs and rhs in comparison */
void comparison();
/** match 'if' and 'else if' conditions */
void multiCondition();
/**
* multiconditions #2
* - Opposite inner conditions => always false
* - (TODO) Same/Overlapping inner condition => always true
* - same condition after early exit => always false
**/
void multiCondition2();
/** @brief %Check for testing for mutual exclusion over ||*/
void checkIncorrectLogicOperator();
/** @brief %Check for suspicious usage of modulo (e.g. "if(var % 4 == 4)") */
void checkModuloAlwaysTrueFalse();
/** @brief Suspicious condition (assignment+comparison) */
void clarifyCondition();
/** @brief Condition is always true/false */
void alwaysTrueFalse();
/** @brief %Check for invalid test for overflow 'x+100 < x' */
void checkInvalidTestForOverflow();
private:
bool isAliased(const std::set<unsigned int> &vars) const;
bool isOverlappingCond(const Token * const cond1, const Token * const cond2, bool pure) const;
void assignIfError(const Token *tok1, const Token *tok2, const std::string &condition, bool result);
void mismatchingBitAndError(const Token *tok1, const MathLib::bigint num1, const Token *tok2, const MathLib::bigint num2);
void badBitmaskCheckError(const Token *tok);
void comparisonError(const Token *tok,
const std::string &bitop,
MathLib::bigint value1,
const std::string &op,
MathLib::bigint value2,
bool result);
void multiConditionError(const Token *tok, unsigned int line1);
void oppositeInnerConditionError(const Token *tok1, const Token* tok2);
void sameConditionAfterEarlyExitError(const Token *cond1, const Token *cond2);
void incorrectLogicOperatorError(const Token *tok, const std::string &condition, bool always, bool inconclusive);
void redundantConditionError(const Token *tok, const std::string &text, bool inconclusive);
void moduloAlwaysTrueFalseError(const Token* tok, const std::string& maxVal);
void clarifyConditionError(const Token *tok, bool assign, bool boolop);
void alwaysTrueFalseError(const Token *tok, bool knownResult);
void invalidTestForOverflow(const Token* tok, bool result);
void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
CheckCondition c(nullptr, settings, errorLogger);
c.assignIfError(nullptr, nullptr, emptyString, false);
c.badBitmaskCheckError(nullptr);
c.comparisonError(nullptr, "&", 6, "==", 1, false);
c.multiConditionError(nullptr,1);
c.mismatchingBitAndError(nullptr, 0xf0, nullptr, 1);
c.oppositeInnerConditionError(nullptr, nullptr);
c.sameConditionAfterEarlyExitError(nullptr, nullptr);
c.incorrectLogicOperatorError(nullptr, "foo > 3 && foo < 4", true, false);
c.redundantConditionError(nullptr, "If x > 11 the condition x > 10 is always true.", false);
c.moduloAlwaysTrueFalseError(nullptr, "1");
c.clarifyConditionError(nullptr, true, false);
c.alwaysTrueFalseError(nullptr, true);
c.invalidTestForOverflow(nullptr, false);
}
static std::string myName() {
return "Condition";
}
std::string classInfo() const {
return "Match conditions with assignments and other conditions:\n"
"- Mismatching assignment and comparison => comparison is always true/false\n"
"- Mismatching lhs and rhs in comparison => comparison is always true/false\n"
"- Detect usage of | where & should be used\n"
"- Detect matching 'if' and 'else if' conditions\n"
"- Mismatching bitand (a &= 0xf0; a &= 1; => a = 0)\n"
"- Opposite inner condition is always false\n"
"- Same condition after early exit is always false\n"
"- Condition that is always true/false\n"
"- Mutual exclusion over || always evaluating to true\n"
"- Comparisons of modulo results that are always true/false.\n"
"- Known variable values => condition is always true/false\n"
"- Invalid test for overflow (for example 'ptr+u < ptr'). Condition is always false unless there is overflow, and overflow is UB.\n";
}
};
/// @}
//---------------------------------------------------------------------------
#endif // checkconditionH