static bool astHasAutoResult(const Token *tok)
{
if (tok->astOperand1() && !astHasAutoResult(tok->astOperand1()))
return false;
if (tok->astOperand2() && !astHasAutoResult(tok->astOperand2()))
return false;
if (tok->isOp())
return true;
if (tok->isLiteral())
return true;
if (tok->isName()) {
// TODO: check function calls, struct members, arrays, etc also
if (!tok->variable())
return false;
if (tok->variable()->isStlType() && !Token::Match(tok->astParent(), "<<|>>"))
return true;
if (tok->variable()->isClass() || tok->variable()->isPointer() || tok->variable()->isReference()) // TODO: Properly handle pointers/references to classes in symbol database
return false;
return true;
}
return false;
}
static bool astHasAutoResult(const Token *tok)
{
if (tok->astOperand1() && !astHasAutoResult(tok->astOperand1()))
return false;
if (tok->astOperand2() && !astHasAutoResult(tok->astOperand2()))
return false;
if (tok->isOp()) {
if ((tok->str() == "<<" || tok->str() == ">>") && tok->astOperand1()) {
const Token* tok2 = tok->astOperand1();
while (tok2 && tok2->str() == "*" && !tok2->astOperand2())
tok2 = tok2->astOperand1();
return tok2 && tok2->variable() && !tok2->variable()->isClass() && !tok2->variable()->isStlType(); // Class or unknown type on LHS: Assume it is a stream
}
return true;
}
if (tok->isLiteral())
return true;
if (tok->isName()) {
// TODO: check function calls, struct members, arrays, etc also
if (!tok->variable())
return false;
if (tok->variable()->isStlType())
return true;
if (tok->variable()->isClass() || tok->variable()->isPointer() || tok->variable()->isReference()) // TODO: Properly handle pointers/references to classes in symbol database
return false;
return true;
}
return false;
}
void CheckAutoVariables::returnReference()
{
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];
if (!scope->function)
continue;
const Token *tok = scope->function->tokenDef;
// have we reached a function that returns a reference?
if (tok->previous() && tok->previous()->str() == "&") {
for (const Token *tok2 = scope->classStart->next(); tok2 && tok2 != scope->classEnd; tok2 = tok2->next()) {
if (tok2->str() != "return")
continue;
// return..
if (Token::Match(tok2, "return %var% ;")) {
// is the returned variable a local variable?
if (isAutoVar(tok2->next())) {
const Variable *var1 = tok2->next()->variable();
// If reference variable is used, check what it references
if (Token::Match(var1->nameToken(), "%var% [=(]")) {
const Token *tok3 = var1->nameToken()->tokAt(2);
if (!Token::Match(tok3, "%var% [);.]"))
continue;
// Only report error if variable that is referenced is
// a auto variable
if (!isAutoVar(tok3))
continue;
}
// report error..
errorReturnReference(tok2);
}
}
// return reference to temporary..
else if (Token::Match(tok2, "return %var% (") &&
Token::simpleMatch(tok2->linkAt(2), ") ;")) {
if (returnTemporary(tok2->next())) {
// report error..
errorReturnTempReference(tok2);
}
}
// Return reference to a literal or the result of a calculation
else if (tok2->astOperand1() && (tok2->astOperand1()->isCalculation() || tok2->next()->isLiteral()) && astHasAutoResult(tok2->astOperand1())) {
errorReturnTempReference(tok2);
}
}
}
}
}
