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Clarify signConversion warning message

This commit is contained in:
Daniel Marjamäki 2019-08-05 12:41:08 +02:00
parent 1718963d9f
commit 20278d9c92
3 changed files with 19 additions and 8 deletions
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21
lib/checktype.cpp
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@ -70,7 +70,7 @@ void CheckType::checkTooBigBitwiseShift()
// get number of bits of lhs // get number of bits of lhs
const ValueType * const lhstype = tok->astOperand1()->valueType(); const ValueType * const lhstype = tok->astOperand1()->valueType();
if (!lhstype || !lhstype->isIntegral() || lhstype->pointer >= 1U) if (!lhstype || !lhstype->isIntegral() || lhstype->pointer >= 1)
continue; continue;
// C11 Standard, section 6.5.7 Bitwise shift operators, states: // C11 Standard, section 6.5.7 Bitwise shift operators, states:
// The integer promotions are performed on each of the operands. // The integer promotions are performed on each of the operands.
@ -237,15 +237,16 @@ void CheckType::checkSignConversion()
tokens.pop(); tokens.pop();
if (!tok1) if (!tok1)
continue; continue;
if (!tok1->getValueLE(-1,mSettings)) const ValueFlow::Value *negativeValue = tok1->getValueLE(-1,mSettings);
if (!negativeValue)
continue; continue;
if (tok1->valueType() && tok1->valueType()->sign != ValueType::Sign::UNSIGNED) if (tok1->valueType() && tok1->valueType()->sign != ValueType::Sign::UNSIGNED)
signConversionError(tok1, tok1->isNumber()); signConversionError(tok1, negativeValue, tok1->isNumber());
} }
} }
} }
void CheckType::signConversionError(const Token *tok, const bool constvalue) void CheckType::signConversionError(const Token *tok, const ValueFlow::Value *negativeValue, const bool constvalue)
{ {
const std::string expr(tok ? tok->expressionString() : "var"); const std::string expr(tok ? tok->expressionString() : "var");
@ -257,7 +258,17 @@ void CheckType::signConversionError(const Token *tok, const bool constvalue)
else else
msg << "Expression '" << expr << "' can have a negative value. That is converted to an unsigned value and used in an unsigned calculation."; msg << "Expression '" << expr << "' can have a negative value. That is converted to an unsigned value and used in an unsigned calculation.";
reportError(tok, Severity::warning, "signConversion", msg.str(), CWE195, false); if (!negativeValue)
reportError(tok, Severity::warning, "signConversion", msg.str(), CWE195, false);
else {
const ErrorPath &errorPath = getErrorPath(tok,negativeValue,"Negative value is converted to an unsigned value");
reportError(errorPath,
Severity::warning,
Check::getMessageId(*negativeValue, "signConversion").c_str(),
msg.str(),
CWE195,
negativeValue->isInconclusive());
}
} }

4
lib/checktype.h
View File

@ -81,7 +81,7 @@ private:
void tooBigBitwiseShiftError(const Token *tok, int lhsbits, const ValueFlow::Value &rhsbits); void tooBigBitwiseShiftError(const Token *tok, int lhsbits, const ValueFlow::Value &rhsbits);
void tooBigSignedBitwiseShiftError(const Token *tok, int lhsbits, const ValueFlow::Value &rhsbits); void tooBigSignedBitwiseShiftError(const Token *tok, int lhsbits, const ValueFlow::Value &rhsbits);
void integerOverflowError(const Token *tok, const ValueFlow::Value &value); void integerOverflowError(const Token *tok, const ValueFlow::Value &value);
void signConversionError(const Token *tok, const bool constvalue); void signConversionError(const Token *tok, const ValueFlow::Value *negativeValue, const bool constvalue);
void longCastAssignError(const Token *tok); void longCastAssignError(const Token *tok);
void longCastReturnError(const Token *tok); void longCastReturnError(const Token *tok);
void floatToIntegerOverflowError(const Token *tok, const ValueFlow::Value &value); void floatToIntegerOverflowError(const Token *tok, const ValueFlow::Value &value);
@ -91,7 +91,7 @@ private:
c.tooBigBitwiseShiftError(nullptr, 32, ValueFlow::Value(64)); c.tooBigBitwiseShiftError(nullptr, 32, ValueFlow::Value(64));
c.tooBigSignedBitwiseShiftError(nullptr, 31, ValueFlow::Value(31)); c.tooBigSignedBitwiseShiftError(nullptr, 31, ValueFlow::Value(31));
c.integerOverflowError(nullptr, ValueFlow::Value(1LL<<32)); c.integerOverflowError(nullptr, ValueFlow::Value(1LL<<32));
c.signConversionError(nullptr, false); c.signConversionError(nullptr, nullptr, false);
c.longCastAssignError(nullptr); c.longCastAssignError(nullptr);
c.longCastReturnError(nullptr); c.longCastReturnError(nullptr);
ValueFlow::Value f; ValueFlow::Value f;

2
test/testtype.cpp
View File

@ -194,7 +194,7 @@ private:
" if (x==0) {}\n" " if (x==0) {}\n"
" return (x-1)*sizeof(int);\n" " return (x-1)*sizeof(int);\n"
"}\n"); "}\n");
ASSERT_EQUALS("[test.cpp:3]: (warning) Expression 'x-1' can have a negative value. That is converted to an unsigned value and used in an unsigned calculation.\n", errout.str()); ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (warning) Expression 'x-1' can have a negative value. That is converted to an unsigned value and used in an unsigned calculation.\n", errout.str());
check("unsigned int f1(signed int x, unsigned int y) {" // x is signed check("unsigned int f1(signed int x, unsigned int y) {" // x is signed
" return x * y;\n" " return x * y;\n"