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Fix 11557: FP derefInvalidIteratorRedundantCheck in and/or condition #4892

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Merged
firewave merged 5 commits into from
Mar 16, 2023
Merged

Fix 11557: FP derefInvalidIteratorRedundantCheck in and/or condition #4892

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065412f
Add impossible values in condition processing
pfultz2 Mar 13, 2023
ca8e12d
Fix FP
pfultz2 Mar 13, 2023
ee1c975
Add test
pfultz2 Mar 13, 2023
8e10308
Format
pfultz2 Mar 13, 2023
74eff8d
Simplify boolean expression
pfultz2 Mar 16, 2023
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63 changes: 40 additions & 23 deletions lib/valueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5970,6 +5970,39 @@ struct ConditionHandler {
return findPath(true_values) | findPath(false_values);
}

Token* getContextAndValues(Token* condTok,
std::list<ValueFlow::Value>& thenValues,
std::list<ValueFlow::Value>& elseValues,
bool known = false) const
{
const MathLib::bigint path = getPath();
const bool allowKnown = path == 0;
const bool allowImpossible = impossible && allowKnown;

bool inverted2 = inverted;
Token* ctx = skipNotAndCasts(condTok, &inverted2);
bool then = !inverted || !inverted2;

if (!Token::Match(condTok, "!=|=|(|.") && condTok != vartok) {
thenValues.insert(thenValues.end(), true_values.cbegin(), true_values.cend());
if (allowImpossible && (known || isConditionKnown(ctx, !then)))
insertImpossible(elseValues, false_values);
}
if (!Token::Match(condTok, "==|!")) {
elseValues.insert(elseValues.end(), false_values.cbegin(), false_values.cend());
if (allowImpossible && (known || isConditionKnown(ctx, then))) {
insertImpossible(thenValues, true_values);
if (isBool())
insertNegateKnown(thenValues, true_values);
}
}

if (inverted2)
std::swap(thenValues, elseValues);

return ctx;
}

Condition() : vartok(nullptr), true_values(), false_values(), inverted(false), impossible(true) {}
};

Expand Down Expand Up @@ -6198,31 +6231,11 @@ struct ConditionHandler {

const MathLib::bigint path = cond.getPath();
const bool allowKnown = path == 0;
const bool allowImpossible = cond.impossible && allowKnown;

std::list<ValueFlow::Value> thenValues;
std::list<ValueFlow::Value> elseValues;

bool inverted = cond.inverted;
Token* ctx = skipNotAndCasts(condTok, &inverted);
bool then = cond.inverted ? !inverted : true;

if (!Token::Match(condTok, "!=|=|(|.") && condTok != cond.vartok) {
thenValues.insert(thenValues.end(), cond.true_values.cbegin(), cond.true_values.cend());
if (allowImpossible && isConditionKnown(ctx, !then))
insertImpossible(elseValues, cond.false_values);
}
if (!Token::Match(condTok, "==|!")) {
elseValues.insert(elseValues.end(), cond.false_values.cbegin(), cond.false_values.cend());
if (allowImpossible && isConditionKnown(ctx, then)) {
insertImpossible(thenValues, cond.true_values);
if (cond.isBool())
insertNegateKnown(thenValues, cond.true_values);
}
}

if (inverted)
std::swap(thenValues, elseValues);
Token* ctx = cond.getContextAndValues(condTok, thenValues, elseValues);

if (Token::Match(ctx->astParent(), "%oror%|&&")) {
Token* parent = ctx->astParent();
Expand All @@ -6237,12 +6250,16 @@ struct ConditionHandler {
if (astIsLHS(parent) && parent->astParent() && parent->astParent()->str() == parent->str()) {
nextExprs.push_back(parent->astParent()->astOperand2());
}
std::list<ValueFlow::Value> andValues;
std::list<ValueFlow::Value> orValues;
cond.getContextAndValues(condTok, andValues, orValues, true);

const std::string& op(parent->str());
std::list<ValueFlow::Value> values;
if (op == "&&")
values = thenValues;
values = andValues;
else if (op == "||")
values = elseValues;
values = orValues;
if (allowKnown && (Token::Match(condTok, "==|!=") || cond.isBool()))
changePossibleToKnown(values);
if (astIsFloat(cond.vartok, false) ||
Expand Down
10 changes: 10 additions & 0 deletions test/teststl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4740,6 +4740,16 @@ class TestStl : public TestFixture {
" return debug_valueflow(it)->second;\n"
"}\n");
ASSERT_EQUALS("", errout.str());

// #11557
check("bool f(const std::vector<int*>& v, std::vector<int*>::iterator it, bool b) {\n"
" if (it == v.end())\n"
" return false;\n"
" if (b && ((it + 1) == v.end() || (*(it + 1)) != nullptr))\n"
" return false;\n"
" return true;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}

void dereferenceInvalidIterator2() {
Expand Down