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invalidTestForOverflow: Refactor; move from checkother to checkcondition

This commit is contained in:
Daniel Marjamäki 2015-11-30 08:51:15 +01:00
parent f6f4f27636
commit fb8cce647c
6 changed files with 89 additions and 88 deletions
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59
lib/checkcondition.cpp
View File

@ -1014,3 +1014,62 @@ void CheckCondition::alwaysTrueFalseError(const Token *tok, bool knownResult)
"knownConditionTrueFalse",
"Condition '" + expr + "' is always " + (knownResult ? "true" : "false"));
}
void CheckCondition::checkInvalidTestForOverflow()
{
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 (!tok->isComparisonOp() || !tok->astOperand1() || !tok->astOperand2())
continue;
const Token *calcToken, *exprToken;
if (tok->str() == "<" && tok->astOperand1()->str() == "+") {
calcToken = tok->astOperand1();
exprToken = tok->astOperand2();
} else if (tok->str() == ">" && tok->astOperand2()->str() == "+") {
calcToken = tok->astOperand2();
exprToken = tok->astOperand1();
} else
continue;
// Only warn for signed integer overflows and pointer overflows.
if (!(calcToken->valueType() && (calcToken->valueType()->pointer || calcToken->valueType()->sign == ValueType::Sign::SIGNED)))
continue;
if (!(exprToken->valueType() && (exprToken->valueType()->pointer || exprToken->valueType()->sign == ValueType::Sign::SIGNED)))
continue;
const Token *termToken;
if (isSameExpression(_tokenizer->isCPP(), exprToken, calcToken->astOperand1(), _settings->library.functionpure))
termToken = calcToken->astOperand2();
else if (isSameExpression(_tokenizer->isCPP(), exprToken, calcToken->astOperand2(), _settings->library.functionpure))
termToken = calcToken->astOperand1();
else
continue;
if (!termToken)
continue;
// Only warn when termToken is always positive
if (termToken->valueType() && termToken->valueType()->sign == ValueType::Sign::UNSIGNED)
invalidTestForOverflow(tok);
else if (termToken->isNumber() && MathLib::isPositive(termToken->str()))
invalidTestForOverflow(tok);
}
}
}
void CheckCondition::invalidTestForOverflow(const Token* tok)
{
std::string errmsg;
errmsg = "Invalid test for overflow '" +
(tok ? tok->expressionString() : std::string("x + u < x")) +
"'. Condition is always false unless there is overflow, and overflow is UB.";
reportError(tok, Severity::warning, "invalidTestForOverflow", errmsg);
}

14
lib/checkcondition.h
View File

@ -50,6 +50,7 @@ public:
checkCondition.clarifyCondition(); // not simplified because ifAssign
checkCondition.oppositeInnerCondition();
checkCondition.checkIncorrectLogicOperator();
checkCondition.checkInvalidTestForOverflow();
}
/** @brief Run checks against the simplified token list */
@ -97,6 +98,9 @@ public:
/** @brief Condition is always true/false */
void alwaysTrueFalse();
/** @brief %Check for invalid test for overflow 'x+100 < x' */
void checkInvalidTestForOverflow();
private:
bool isOverlappingCond(const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions) const;
@ -122,6 +126,8 @@ private:
void alwaysTrueFalseError(const Token *tok, bool knownResult);
void invalidTestForOverflow(const Token* tok);
void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
CheckCondition c(0, settings, errorLogger);
@ -136,6 +142,7 @@ private:
c.moduloAlwaysTrueFalseError(0, "1");
c.clarifyConditionError(0, true, false);
c.alwaysTrueFalseError(0, true);
c.invalidTestForOverflow(0);
}
static std::string myName() {
@ -150,10 +157,11 @@ private:
"- Detect matching 'if' and 'else if' conditions\n"
"- Mismatching bitand (a &= 0xf0; a &= 1; => a = 0)\n"
"- Find dead code which is inaccessible due to the counter-conditions check in nested if statements\n"
"- condition that is always true/false\n"
"- mutual exclusion over || always evaluating to true\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";
"- 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";
}
};
/// @}

59
lib/checkother.cpp
View File

@ -2455,62 +2455,3 @@ void CheckOther::unusedLabelError(const Token* tok)
reportError(tok, Severity::style, "unusedLabel",
"Label '" + (tok?tok->str():emptyString) + "' is not used.");
}
void CheckOther::checkInvalidTestForOverflow()
{
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 (!tok->isComparisonOp() || !tok->astOperand1() || !tok->astOperand2())
continue;
const Token *calcToken, *exprToken;
if (Token::Match(tok, "<|<=") && tok->astOperand1()->str() == "+") {
calcToken = tok->astOperand1();
exprToken = tok->astOperand2();
} else if (Token::Match(tok, ">|>=") && tok->astOperand2()->str() == "+") {
calcToken = tok->astOperand2();
exprToken = tok->astOperand1();
} else
continue;
// Only warn for signed integer overflows and pointer overflows.
if (!(calcToken->valueType() && (calcToken->valueType()->pointer || calcToken->valueType()->sign == ValueType::Sign::SIGNED)))
continue;
if (!(exprToken->valueType() && (exprToken->valueType()->pointer || exprToken->valueType()->sign == ValueType::Sign::SIGNED)))
continue;
const Token *termToken;
if (isSameExpression(_tokenizer->isCPP(), exprToken, calcToken->astOperand1(), _settings->library.functionpure))
termToken = calcToken->astOperand2();
else if (isSameExpression(_tokenizer->isCPP(), exprToken, calcToken->astOperand2(), _settings->library.functionpure))
termToken = calcToken->astOperand1();
else
continue;
if (!termToken)
continue;
// Only warn when termToken is always positive
if (termToken->valueType() && termToken->valueType()->sign == ValueType::Sign::UNSIGNED)
invalidTestForOverflow(tok);
else if (termToken->isNumber() && MathLib::isPositive(termToken->str()))
invalidTestForOverflow(tok);
}
}
}
void CheckOther::invalidTestForOverflow(const Token* tok)
{
std::string errmsg;
errmsg = "Invalid test for overflow '" +
(tok ? tok->expressionString() : std::string("x + u < x")) +
"'. Condition is always false unless there is overflow, and overflow is UB.";
reportError(tok, Severity::warning, "invalidTestForOverflow", errmsg);
}

7
lib/checkother.h
View File

@ -70,7 +70,6 @@ public:
checkOther.checkZeroDivision();
checkOther.checkInterlockedDecrement();
checkOther.checkUnusedLabel();
checkOther.checkInvalidTestForOverflow();
}
/** @brief Run checks against the simplified token list */
@ -204,9 +203,6 @@ public:
/** @brief %Check for unused labels */
void checkUnusedLabel();
/** @brief %Check for invalid test for overflow 'x+100 < x' */
void checkInvalidTestForOverflow();
private:
// Error messages..
void checkComparisonFunctionIsAlwaysTrueOrFalseError(const Token* tok, const std::string &strFunctionName, const std::string &varName, const bool result);
@ -255,7 +251,6 @@ private:
void redundantPointerOpError(const Token* tok, const std::string& varname, bool inconclusive);
void raceAfterInterlockedDecrementError(const Token* tok);
void unusedLabelError(const Token* tok);
void invalidTestForOverflow(const Token* tok);
void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
CheckOther c(0, settings, errorLogger);
@ -310,7 +305,6 @@ private:
c.commaSeparatedReturnError(0);
c.redundantPointerOpError(0, "varname", false);
c.unusedLabelError(0);
c.invalidTestForOverflow(0);
}
static std::string myName() {
@ -333,7 +327,6 @@ private:
// warning
"- either division by zero or useless condition\n"
"- memset() with a value out of range as the 2nd parameter\n"
"- invalid test for overflow\n"
// performance
"- redundant data copying for const variable\n"

19
test/testcondition.cpp
View File

@ -79,6 +79,8 @@ private:
TEST_CASE(clarifyCondition6); // #3818
TEST_CASE(alwaysTrue);
TEST_CASE(checkInvalidTestForOverflow);
}
void check(const char code[], const char* filename = "test.cpp") {
@ -1604,6 +1606,23 @@ private:
"}");
ASSERT_EQUALS("", errout.str());
}
void checkInvalidTestForOverflow() {
check("void f(char *p, unsigned int x) {\n"
" assert((p + x) < p);\n"
"}");
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());
check("void f(signed int x) {\n"
" assert(x + 100 < x);\n"
"}");
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());
check("void f(signed int x) {\n" // unsigned overflow => dont warn
" assert(x + 100U < x);\n"
"}");
ASSERT_EQUALS("", errout.str());
}
};
REGISTER_TEST(TestCondition)

19
test/testother.cpp
View File

@ -157,8 +157,6 @@ private:
TEST_CASE(raceAfterInterlockedDecrement);
TEST_CASE(testUnusedLabel);
TEST_CASE(checkInvalidTestForOverflow);
}
void check(const char code[], const char *filename = nullptr, bool experimental = false, bool inconclusive = true, bool runSimpleChecks=true, Settings* settings = 0) {
@ -6019,23 +6017,6 @@ private:
"}");
ASSERT_EQUALS("", errout.str());
}
void checkInvalidTestForOverflow() {
check("void f(char *p, unsigned int x) {\n"
" assert((p + x) < p);\n"
"}");
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());
check("void f(signed int x) {\n"
" assert(x + 100 < x);\n"
"}");
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());
check("void f(signed int x) {\n" // unsigned overflow => dont warn
" assert(x + 100U < x);\n"
"}");
ASSERT_EQUALS("", errout.str());
}
};
REGISTER_TEST(TestOther)