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Fix 10843: FP: danglingTemporaryLifetime (#3908) 

* Fix 10843: FP: danglingTemporaryLifetime

* Format
This commit is contained in:
Paul Fultz II 2022-03-16 11:11:49 -05:00 committed by GitHub
parent fb1170b10b
commit 40ff9edad6
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2 changed files with 102 additions and 85 deletions
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160
lib/valueflow.cpp
View File

@ -3268,9 +3268,6 @@ static bool isLifetimeBorrowed(const ValueType *vt, const ValueType *vtParent)
return true;
if (vtParent->str() == vt->str())
return true;
if (vtParent->pointer == vt->pointer && vtParent->type == vt->type && vtParent->isIntegral())
// sign conversion
return true;
}
return false;
@ -3345,42 +3342,6 @@ static bool isDifferentType(const Token* src, const Token* dst)
return false;
}
static std::vector<ValueType> getParentValueTypes(const Token* tok, const Settings* settings = nullptr)
{
if (!tok)
return {};
if (!tok->astParent())
return {};
if (Token::Match(tok->astParent(), "(|{|,")) {
int argn = -1;
const Token* ftok = getTokenArgumentFunction(tok, argn);
if (ftok && ftok->function()) {
std::vector<ValueType> result;
std::vector<const Variable*> argsVars = getArgumentVars(ftok, argn);
for (const Variable* var : getArgumentVars(ftok, argn)) {
if (!var)
continue;
if (!var->valueType())
continue;
result.push_back(*var->valueType());
}
return result;
}
}
if (settings && Token::Match(tok->astParent()->tokAt(-2), ". push_back|push_front|insert|push (") &&
astIsContainer(tok->astParent()->tokAt(-2)->astOperand1())) {
const Token* contTok = tok->astParent()->tokAt(-2)->astOperand1();
const ValueType* vtCont = contTok->valueType();
if (!vtCont->containerTypeToken)
return {};
ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings);
return {std::move(vtParent)};
}
if (tok->astParent()->valueType())
return {*tok->astParent()->valueType()};
return {};
}
static bool isInConstructorList(const Token* tok)
{
if (!tok)
@ -3400,6 +3361,58 @@ static bool isInConstructorList(const Token* tok)
return Token::simpleMatch(parent, ":") && !Token::simpleMatch(parent->astParent(), "?");
}
static std::vector<ValueType> getParentValueTypes(const Token* tok,
const Settings* settings = nullptr,
const Token** parent = nullptr)
{
if (!tok)
return {};
if (!tok->astParent())
return {};
if (isInConstructorList(tok)) {
if (parent)
*parent = tok->astParent()->astOperand1();
if (tok->astParent()->astOperand1()->valueType())
return {*tok->astParent()->astOperand1()->valueType()};
return {};
} else if (Token::Match(tok->astParent(), "(|{|,")) {
int argn = -1;
const Token* ftok = getTokenArgumentFunction(tok, argn);
if (ftok && ftok->function()) {
std::vector<ValueType> result;
std::vector<const Variable*> argsVars = getArgumentVars(ftok, argn);
const Token* nameTok = nullptr;
for (const Variable* var : getArgumentVars(ftok, argn)) {
if (!var)
continue;
if (!var->valueType())
continue;
nameTok = var->nameToken();
result.push_back(*var->valueType());
}
if (result.size() == 1 && nameTok && parent) {
*parent = nameTok;
}
return result;
}
}
if (settings && Token::Match(tok->astParent()->tokAt(-2), ". push_back|push_front|insert|push (") &&
astIsContainer(tok->astParent()->tokAt(-2)->astOperand1())) {
const Token* contTok = tok->astParent()->tokAt(-2)->astOperand1();
const ValueType* vtCont = contTok->valueType();
if (!vtCont->containerTypeToken)
return {};
ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings);
return {std::move(vtParent)};
}
if (Token::Match(tok->astParent(), "return|(|{|%assign%") && parent) {
*parent = tok->astParent();
}
if (tok->astParent()->valueType())
return {*tok->astParent()->valueType()};
return {};
}
bool isLifetimeBorrowed(const Token *tok, const Settings *settings)
{
if (!tok)
@ -3408,42 +3421,21 @@ bool isLifetimeBorrowed(const Token *tok, const Settings *settings)
return true;
if (!tok->astParent())
return true;
if (isInConstructorList(tok)) {
const Token* parent = tok->astParent()->astOperand1();
const Token* parent = nullptr;
const ValueType* vt = tok->valueType();
const ValueType* vtParent = parent->valueType();
if (isLifetimeBorrowed(vt, vtParent))
return true;
if (isLifetimeOwned(vt, vtParent))
return false;
if (isDifferentType(tok, parent))
return false;
} else if (!Token::Match(tok->astParent()->previous(), "%name% (") && !Token::simpleMatch(tok->astParent(), ",")) {
if (!Token::simpleMatch(tok, "{")) {
const ValueType *vt = tok->valueType();
const ValueType *vtParent = tok->astParent()->valueType();
if (isLifetimeBorrowed(vt, vtParent))
return true;
if (isLifetimeOwned(vt, vtParent))
return false;
}
if (Token::Match(tok->astParent(), "return|(|{|%assign%")) {
if (isDifferentType(tok, tok->astParent()))
return false;
}
} else if (Token::Match(tok->astParent()->tokAt(-3), "%var% . push_back|push_front|insert|push (") &&
astIsContainer(tok->astParent()->tokAt(-3))) {
const ValueType *vt = tok->valueType();
const ValueType *vtCont = tok->astParent()->tokAt(-3)->valueType();
if (!vtCont->containerTypeToken)
return true;
ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings);
std::vector<ValueType> vtParents = getParentValueTypes(tok, settings, &parent);
if (vt) {
for (const ValueType& vtParent : vtParents) {
if (isLifetimeBorrowed(vt, &vtParent))
return true;
if (isLifetimeOwned(vt, &vtParent))
return false;
}
}
if (parent) {
if (isDifferentType(tok, parent))
return false;
}
return true;
}
@ -4063,15 +4055,13 @@ static void valueFlowLifetimeConstructor(Token* tok,
const Token* expr = tok2->astOperand2();
if (!var)
continue;
if (!isLifetimeBorrowed(expr, settings))
continue;
const Variable* argvar = getLifetimeVariable(expr);
if (!argvar)
argvar = expr->variable();
if (argvar && argvar->isArgument()) {
paramCapture[argvar] =
argvar->isReference() ? LifetimeCapture::ByReference : LifetimeCapture::ByValue;
} else if (!var->isReference()) {
if (var->isReference() || var->isRValueReference()) {
if (argvar && argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) {
paramCapture[argvar] = LifetimeCapture::ByReference;
}
} else {
bool found = false;
for (const ValueFlow::Value& v : expr->values()) {
if (!v.isLifetimeValue())
continue;
@ -4082,13 +4072,19 @@ static void valueFlowLifetimeConstructor(Token* tok,
const Variable* lifeVar = v.tokvalue->variable();
if (!lifeVar)
continue;
if (!lifeVar->isArgument())
continue;
if (!lifeVar->isReference())
continue;
paramCapture[lifeVar] = LifetimeCapture::ByReference;
LifetimeCapture c = LifetimeCapture::Undefined;
if (!v.isArgumentLifetimeValue() && (lifeVar->isReference() || lifeVar->isRValueReference()))
c = LifetimeCapture::ByReference;
else if (v.isArgumentLifetimeValue())
c = LifetimeCapture::ByValue;
if (c != LifetimeCapture::Undefined) {
paramCapture[lifeVar] = c;
found = true;
}
}
if (!found && argvar && argvar->isArgument())
paramCapture[argvar] = LifetimeCapture::ByValue;
}
}
// TODO: Use SubExpressionAnalyzer for members
LifetimeStore::forEach(args,

21
test/testautovariables.cpp
View File

@ -3197,6 +3197,27 @@ private:
" return A{0};\n"
"}\n");
TODO_ASSERT_EQUALS("error", "", errout.str());
check("struct A {\n"
" int n;\n"
" A(const int &x) : n(x) {}\n"
"};\n"
"A f() {\n"
" A m(4);\n"
" return m;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("struct B {};\n"
"struct A {\n"
" B n;\n"
" A(const B &x) : n(x) {}\n"
"};\n"
"A f() {\n"
" A m(B{});\n"
" return m;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}
void danglingLifetimeAggegrateConstructor() {