Fixed #7184 (Invalid test for overflow 'p + x < p')
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e9b84a4f06
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26a07265a8
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@ -2455,3 +2455,59 @@ void CheckOther::unusedLabelError(const Token* tok)
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reportError(tok, Severity::style, "unusedLabel",
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reportError(tok, Severity::style, "unusedLabel",
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"Label '" + (tok?tok->str():emptyString) + "' is not used.");
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"Label '" + (tok?tok->str():emptyString) + "' is not used.");
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}
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}
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void CheckOther::checkInvalidTestForOverflow()
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{
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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const std::size_t functions = symbolDatabase->functionScopes.size();
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for (std::size_t i = 0; i < functions; ++i) {
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const Scope * scope = symbolDatabase->functionScopes[i];
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for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
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if (!tok->isComparisonOp() || !tok->astOperand1() || !tok->astOperand2())
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continue;
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const Token *calcToken, *exprToken;
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if (Token::Match(tok, "<|<=") && tok->astOperand1()->str() == "+") {
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calcToken = tok->astOperand1();
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exprToken = tok->astOperand2();
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} else if (Token::Match(tok, ">|>=") && tok->astOperand2()->str() == "+") {
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calcToken = tok->astOperand2();
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exprToken = tok->astOperand1();
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} else
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continue;
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// Only warn for signed integer overflows and pointer overflows.
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if (!(calcToken->valueType() && (calcToken->valueType()->pointer || calcToken->valueType()->sign == ValueType::Sign::SIGNED)))
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continue;
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if (!(exprToken->valueType() && (exprToken->valueType()->pointer || exprToken->valueType()->sign == ValueType::Sign::SIGNED)))
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continue;
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const Token *termToken;
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if (isSameExpression(_tokenizer->isCPP(), exprToken, calcToken->astOperand1(), _settings->library.functionpure))
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termToken = calcToken->astOperand2();
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else if (isSameExpression(_tokenizer->isCPP(), exprToken, calcToken->astOperand2(), _settings->library.functionpure))
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termToken = calcToken->astOperand1();
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else
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continue;
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if (!termToken)
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continue;
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// Only warn when termToken is always positive
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if (termToken->valueType() && termToken->valueType()->sign == ValueType::Sign::UNSIGNED)
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invalidTestForOverflow(tok);
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else if (termToken->isNumber() && MathLib::isPositive(termToken->str()))
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invalidTestForOverflow(tok);
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}
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}
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}
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void CheckOther::invalidTestForOverflow(const Token* tok)
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{
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std::string errmsg;
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errmsg = "Invalid test for overflow '" +
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(tok ? tok->expressionString() : std::string("x + u < x")) +
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"'. Condition is always false unless there is overflow, and overflow is UB.";
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reportError(tok, Severity::warning, "invalidTestForOverflow", errmsg);
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}
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@ -70,6 +70,7 @@ public:
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checkOther.checkZeroDivision();
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checkOther.checkZeroDivision();
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checkOther.checkInterlockedDecrement();
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checkOther.checkInterlockedDecrement();
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checkOther.checkUnusedLabel();
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checkOther.checkUnusedLabel();
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checkOther.checkInvalidTestForOverflow();
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}
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}
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/** @brief Run checks against the simplified token list */
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/** @brief Run checks against the simplified token list */
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@ -203,6 +204,9 @@ public:
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/** @brief %Check for unused labels */
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/** @brief %Check for unused labels */
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void checkUnusedLabel();
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void checkUnusedLabel();
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/** @brief %Check for invalid test for overflow 'x+100 < x' */
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void checkInvalidTestForOverflow();
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private:
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private:
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// Error messages..
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// Error messages..
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void checkComparisonFunctionIsAlwaysTrueOrFalseError(const Token* tok, const std::string &strFunctionName, const std::string &varName, const bool result);
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void checkComparisonFunctionIsAlwaysTrueOrFalseError(const Token* tok, const std::string &strFunctionName, const std::string &varName, const bool result);
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@ -251,6 +255,7 @@ private:
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void redundantPointerOpError(const Token* tok, const std::string& varname, bool inconclusive);
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void redundantPointerOpError(const Token* tok, const std::string& varname, bool inconclusive);
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void raceAfterInterlockedDecrementError(const Token* tok);
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void raceAfterInterlockedDecrementError(const Token* tok);
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void unusedLabelError(const Token* tok);
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void unusedLabelError(const Token* tok);
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void invalidTestForOverflow(const Token* tok);
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void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
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void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
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CheckOther c(0, settings, errorLogger);
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CheckOther c(0, settings, errorLogger);
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@ -305,6 +310,7 @@ private:
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c.commaSeparatedReturnError(0);
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c.commaSeparatedReturnError(0);
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c.redundantPointerOpError(0, "varname", false);
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c.redundantPointerOpError(0, "varname", false);
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c.unusedLabelError(0);
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c.unusedLabelError(0);
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c.invalidTestForOverflow(0);
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}
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}
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static std::string myName() {
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static std::string myName() {
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@ -327,6 +333,7 @@ private:
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// warning
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// warning
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"- either division by zero or useless condition\n"
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"- either division by zero or useless condition\n"
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"- memset() with a value out of range as the 2nd parameter\n"
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"- memset() with a value out of range as the 2nd parameter\n"
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"- invalid test for overflow\n"
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// performance
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// performance
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"- redundant data copying for const variable\n"
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"- redundant data copying for const variable\n"
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@ -157,6 +157,8 @@ private:
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TEST_CASE(raceAfterInterlockedDecrement);
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TEST_CASE(raceAfterInterlockedDecrement);
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TEST_CASE(testUnusedLabel);
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TEST_CASE(testUnusedLabel);
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TEST_CASE(checkInvalidTestForOverflow);
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}
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}
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void check(const char code[], const char *filename = nullptr, bool experimental = false, bool inconclusive = true, bool runSimpleChecks=true, Settings* settings = 0) {
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void check(const char code[], const char *filename = nullptr, bool experimental = false, bool inconclusive = true, bool runSimpleChecks=true, Settings* settings = 0) {
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@ -6017,6 +6019,23 @@ private:
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"}");
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"}");
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ASSERT_EQUALS("", errout.str());
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ASSERT_EQUALS("", errout.str());
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}
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}
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void checkInvalidTestForOverflow() {
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check("void f(char *p, unsigned int x) {\n"
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" assert((p + x) < p);\n"
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"}");
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ASSERT_EQUALS("[test.cpp:2]: (warning) Invalid test for overflow '(p+x)<p'. Condition is always false unless there is overflow, and overflow is UB.\n", errout.str());
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check("void f(signed int x) {\n"
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" assert(x + 100 < x);\n"
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"}");
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ASSERT_EQUALS("[test.cpp:2]: (warning) Invalid test for overflow 'x+100<x'. Condition is always false unless there is overflow, and overflow is UB.\n", errout.str());
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check("void f(signed int x) {\n" // unsigned overflow => dont warn
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" assert(x + 100U < x);\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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}
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};
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};
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REGISTER_TEST(TestOther)
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REGISTER_TEST(TestOther)
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