void CheckLeakAutoVar::checkScope(const Token * const startToken,
VarInfo *varInfo,
std::set<unsigned int> notzero)
{
std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo->alloctype;
std::map<unsigned int, std::string> &possibleUsage = varInfo->possibleUsage;
const std::set<unsigned int> conditionalAlloc(varInfo->conditionalAlloc);
// Parse all tokens
const Token * const endToken = startToken->link();
for (const Token *tok = startToken; tok && tok != endToken; tok = tok->next()) {
if (!tok->scope()->isExecutable()) {
tok = tok->scope()->classEnd;
if (!tok) // Ticket #6666 (crash upon invalid code)
break;
}
// Deallocation and then dereferencing pointer..
if (tok->varId() > 0) {
const std::map<unsigned int, VarInfo::AllocInfo>::const_iterator var = alloctype.find(tok->varId());
if (var != alloctype.end()) {
if (var->second.status == VarInfo::DEALLOC && tok->strAt(-1) != "&" && (!Token::Match(tok, "%name% =") || tok->strAt(-1) == "*")) {
deallocUseError(tok, tok->str());
} else if (Token::simpleMatch(tok->tokAt(-2), "= &")) {
varInfo->erase(tok->varId());
} else if (tok->strAt(-1) == "=") {
varInfo->erase(tok->varId());
}
} else if (Token::Match(tok->previous(), "& %name% = %var% ;")) {
varInfo->referenced.insert(tok->tokAt(2)->varId());
}
}
if (tok->str() == "(" && tok->previous()->isName()) {
VarInfo::AllocInfo allocation(0, VarInfo::NOALLOC);
functionCall(tok->previous(), varInfo, allocation);
tok = tok->link();
continue;
}
// look for end of statement
if (!Token::Match(tok, "[;{}]") || Token::Match(tok->next(), "[;{}]"))
continue;
tok = tok->next();
if (!tok || tok == endToken)
break;
// parse statement, skip to last member
while (Token::Match(tok, "%name% ::|. %name% !!("))
tok = tok->tokAt(2);
// assignment..
if (Token::Match(tok, "%var% =")) {
// taking address of another variable..
if (Token::Match(tok->next(), "= %var% [+;]")) {
if (tok->tokAt(2)->varId() != tok->varId()) {
// If variable points at allocated memory => error
leakIfAllocated(tok, *varInfo);
// no multivariable checking currently => bail out for rhs variables
for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
break;
}
if (tok2->varId()) {
varInfo->erase(tok2->varId());
}
}
}
}
// is variable used in rhs?
bool used_in_rhs = false;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
break;
}
if (tok->varId() == tok2->varId()) {
used_in_rhs = true;
break;
}
}
// TODO: Better checking how the pointer is used in rhs?
if (used_in_rhs)
continue;
// Variable has already been allocated => error
if (conditionalAlloc.find(tok->varId()) == conditionalAlloc.end())
leakIfAllocated(tok, *varInfo);
varInfo->erase(tok->varId());
// not a local variable nor argument?
const Variable *var = tok->variable();
if (var && !var->isArgument() && (!var->isLocal() || var->isStatic()))
continue;
// Don't check reference variables
if (var && var->isReference())
continue;
// non-pod variable
if (_tokenizer->isCPP()) {
if (!var)
continue;
// Possibly automatically deallocated memory
if (!var->typeStartToken()->isStandardType() && Token::Match(tok, "%var% = new"))
continue;
}
// allocation?
if (tok->next()->astOperand2() && Token::Match(tok->next()->astOperand2()->previous(), "%type% (")) {
int i = _settings->library.alloc(tok->next()->astOperand2()->previous());
if (i > 0) {
alloctype[tok->varId()].type = i;
alloctype[tok->varId()].status = VarInfo::ALLOC;
}
} else if (_tokenizer->isCPP() && tok->strAt(2) == "new") {
alloctype[tok->varId()].type = -1;
alloctype[tok->varId()].status = VarInfo::ALLOC;
}
// Assigning non-zero value variable. It might be used to
// track the execution for a later if condition.
if (Token::Match(tok->tokAt(2), "%num% ;") && MathLib::toLongNumber(tok->strAt(2)) != 0)
notzero.insert(tok->varId());
else if (Token::Match(tok->tokAt(2), "- %type% ;") && tok->tokAt(3)->isUpperCaseName())
notzero.insert(tok->varId());
else
notzero.erase(tok->varId());
}
// if/else
else if (Token::simpleMatch(tok, "if (")) {
// Parse function calls inside the condition
for (const Token *innerTok = tok->tokAt(2); innerTok; innerTok = innerTok->next()) {
if (innerTok->str() == ")")
break;
if (innerTok->str() == "(" && innerTok->previous()->isName()) {
VarInfo::AllocInfo allocation(_settings->library.dealloc(tok), VarInfo::DEALLOC);
if (allocation.type == 0)
allocation.status = VarInfo::NOALLOC;
functionCall(innerTok->previous(), varInfo, allocation);
innerTok = innerTok->link();
}
}
const Token *tok2 = tok->linkAt(1);
if (Token::simpleMatch(tok2, ") {")) {
VarInfo varInfo1(*varInfo); // VarInfo for if code
VarInfo varInfo2(*varInfo); // VarInfo for else code
// Recursively scan variable comparisons in condition
std::stack<const Token *> tokens;
tokens.push(tok->next()->astOperand2());
while (!tokens.empty()) {
const Token *tok3 = tokens.top();
tokens.pop();
if (!tok3)
continue;
if (tok3->str() == "&&") {
tokens.push(tok3->astOperand1());
tokens.push(tok3->astOperand2());
continue;
}
if (tok3->str() == "(" && Token::Match(tok3->astOperand1(), "UNLIKELY|LIKELY")) {
tokens.push(tok3->astOperand2());
continue;
}
const Token *vartok = nullptr;
if (astIsVariableComparison(tok3, "!=", "0", &vartok)) {
varInfo2.erase(vartok->varId());
if (notzero.find(vartok->varId()) != notzero.end())
varInfo2.clear();
} else if (astIsVariableComparison(tok3, "==", "0", &vartok)) {
varInfo1.erase(vartok->varId());
} else if (astIsVariableComparison(tok3, "<", "0", &vartok)) {
varInfo1.erase(vartok->varId());
} else if (astIsVariableComparison(tok3, ">", "0", &vartok)) {
varInfo2.erase(vartok->varId());
} else if (astIsVariableComparison(tok3, "==", "-1", &vartok)) {
varInfo1.erase(vartok->varId());
}
}
checkScope(tok2->next(), &varInfo1, notzero);
tok2 = tok2->linkAt(1);
if (Token::simpleMatch(tok2, "} else {")) {
checkScope(tok2->tokAt(2), &varInfo2, notzero);
tok = tok2->linkAt(2)->previous();
} else {
tok = tok2->previous();
}
VarInfo old;
old.swap(*varInfo);
// Conditional allocation in varInfo1
std::map<unsigned int, VarInfo::AllocInfo>::const_iterator it;
for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
if (varInfo2.alloctype.find(it->first) == varInfo2.alloctype.end() &&
old.alloctype.find(it->first) == old.alloctype.end()) {
varInfo->conditionalAlloc.insert(it->first);
}
}
// Conditional allocation in varInfo2
for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
if (varInfo1.alloctype.find(it->first) == varInfo1.alloctype.end() &&
old.alloctype.find(it->first) == old.alloctype.end()) {
varInfo->conditionalAlloc.insert(it->first);
}
}
// Conditional allocation/deallocation
for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
if (it->second.status == VarInfo::DEALLOC && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
varInfo->conditionalAlloc.erase(it->first);
varInfo2.erase(it->first);
}
}
for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
if (it->second.status == VarInfo::DEALLOC && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
varInfo->conditionalAlloc.erase(it->first);
varInfo1.erase(it->first);
}
}
alloctype.insert(varInfo1.alloctype.begin(), varInfo1.alloctype.end());
alloctype.insert(varInfo2.alloctype.begin(), varInfo2.alloctype.end());
possibleUsage.insert(varInfo1.possibleUsage.begin(), varInfo1.possibleUsage.end());
possibleUsage.insert(varInfo2.possibleUsage.begin(), varInfo2.possibleUsage.end());
}
}
// unknown control.. (TODO: handle loops)
else if ((Token::Match(tok, "%type% (") && Token::simpleMatch(tok->linkAt(1), ") {")) || Token::simpleMatch(tok, "do {")) {
varInfo->clear();
break;
}
// return
else if (tok->str() == "return") {
ret(tok, *varInfo);
varInfo->clear();
}
// throw
else if (_tokenizer->isCPP() && tok->str() == "throw") {
bool tryFound = false;
const Scope* scope = tok->scope();
while (scope && scope->isExecutable()) {
if (scope->type == Scope::eTry)
tryFound = true;
scope = scope->nestedIn;
}
// If the execution leaves the function then treat it as return
if (!tryFound)
ret(tok, *varInfo);
varInfo->clear();
}
// Function call..
else if (Token::Match(tok, "%type% (")) {
VarInfo::AllocInfo allocation(_settings->library.dealloc(tok), VarInfo::DEALLOC);
if (allocation.type == 0)
allocation.status = VarInfo::NOALLOC;
functionCall(tok, varInfo, allocation);
tok = tok->next()->link();
// Handle scopes that might be noreturn
if (allocation.status == VarInfo::NOALLOC && Token::simpleMatch(tok, ") ; }")) {
const std::string &functionName(tok->link()->previous()->str());
bool unknown = false;
if (_tokenizer->IsScopeNoReturn(tok->tokAt(2), &unknown)) {
if (!unknown)
varInfo->clear();
else if (_settings->library.leakignore.find(functionName) == _settings->library.leakignore.end() &&
_settings->library.use.find(functionName) == _settings->library.use.end())
varInfo->possibleUsageAll(functionName);
}
}
continue;
}
// delete
else if (_tokenizer->isCPP() && tok->str() == "delete") {
if (tok->strAt(1) == "[")
tok = tok->tokAt(3);
else
tok = tok->next();
while (Token::Match(tok, "%name% ::|."))
tok = tok->tokAt(2);
if (tok->varId() && tok->strAt(1) != "[") {
VarInfo::AllocInfo allocation(-1, VarInfo::DEALLOC);
changeAllocStatus(varInfo, allocation, tok, tok);
}
}
// goto => weird execution path
else if (tok->str() == "goto") {
varInfo->clear();
}
// continue/break
else if (Token::Match(tok, "continue|break ;")) {
varInfo->clear();
}
}
}
bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var, bool * const possibleInit, bool * const noreturn, Alloc* const alloc, const std::string &membervar)
{
const bool suppressErrors(possibleInit && *possibleInit);
const bool printDebug = _settings->debugwarnings;
if (possibleInit)
*possibleInit = false;
unsigned int number_of_if = 0;
if (var.declarationId() == 0U)
return true;
// variable values
std::map<unsigned int, VariableValue> variableValue;
for (; tok; tok = tok->next()) {
// End of scope..
if (tok->str() == "}") {
if (number_of_if && possibleInit)
*possibleInit = true;
// might be a noreturn function..
if (_tokenizer->IsScopeNoReturn(tok)) {
if (noreturn)
*noreturn = true;
return false;
}
break;
}
// Unconditional inner scope or try..
if (tok->str() == "{" && Token::Match(tok->previous(), ";|{|}|try")) {
if (checkScopeForVariable(tok->next(), var, possibleInit, noreturn, alloc, membervar))
return true;
tok = tok->link();
continue;
}
// assignment with nonzero constant..
if (Token::Match(tok->previous(), "[;{}] %var% = - %name% ;"))
variableValue[tok->varId()] = !VariableValue(0);
// Inner scope..
else if (Token::simpleMatch(tok, "if (")) {
bool alwaysTrue = false;
bool alwaysFalse = false;
conditionAlwaysTrueOrFalse(tok->next()->astOperand2(), variableValue, &alwaysTrue, &alwaysFalse);
// initialization / usage in condition..
if (!alwaysTrue && checkIfForWhileHead(tok->next(), var, suppressErrors, bool(number_of_if == 0), *alloc, membervar))
return true;
// checking if a not-zero variable is zero => bail out
unsigned int condVarId = 0;
VariableValue condVarValue(0);
const Token *condVarTok = nullptr;
if (alwaysFalse)
;
else if (Token::simpleMatch(tok, "if (") &&
astIsVariableComparison(tok->next()->astOperand2(), "!=", "0", &condVarTok)) {
std::map<unsigned int,VariableValue>::const_iterator it = variableValue.find(condVarTok->varId());
if (it != variableValue.end() && it->second != 0)
return true; // this scope is not fully analysed => return true
else {
condVarId = condVarTok->varId();
condVarValue = !VariableValue(0);
}
} else if (Token::simpleMatch(tok, "if (") && Token::Match(tok->next()->astOperand2(), "==|!=")) {
const Token *condition = tok->next()->astOperand2();
const Token *lhs = condition->astOperand1();
const Token *rhs = condition->astOperand2();
const Token *vartok = rhs && rhs->isNumber() ? lhs : rhs;
const Token *numtok = rhs && rhs->isNumber() ? rhs : lhs;
while (Token::simpleMatch(vartok, "."))
vartok = vartok->astOperand2();
if (vartok && vartok->varId() && numtok) {
std::map<unsigned int,VariableValue>::const_iterator it = variableValue.find(vartok->varId());
if (it != variableValue.end() && it->second != MathLib::toLongNumber(numtok->str()))
return true; // this scope is not fully analysed => return true
else {
condVarId = vartok->varId();
condVarValue = VariableValue(MathLib::toLongNumber(numtok->str()));
if (condition->str() == "!=")
condVarValue = !condVarValue;
}
}
}
// goto the {
tok = tok->next()->link()->next();
if (!tok)
break;
if (tok->str() == "{") {
bool possibleInitIf((!alwaysTrue && number_of_if > 0) || suppressErrors);
bool noreturnIf = false;
const bool initif = !alwaysFalse && checkScopeForVariable(tok->next(), var, &possibleInitIf, &noreturnIf, alloc, membervar);
// bail out for such code:
// if (a) x=0; // conditional initialization
// if (b) return; // cppcheck doesn't know if b can be false when a is false.
// x++; // it's possible x is always initialized
if (!alwaysTrue && noreturnIf && number_of_if > 0) {
if (printDebug) {
std::string condition;
for (const Token *tok2 = tok->linkAt(-1); tok2 != tok; tok2 = tok2->next()) {
condition += tok2->str();
if (tok2->isName() && tok2->next()->isName())
condition += ' ';
}
reportError(tok, Severity::debug, "debug", "bailout uninitialized variable checking for '" + var.name() + "'. can't determine if this condition can be false when previous condition is false: " + condition);
}
return true;
}
if (alwaysTrue && (initif || noreturnIf))
return true;
std::map<unsigned int, VariableValue> varValueIf;
if (!alwaysFalse && !initif && !noreturnIf) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}.] %name% = - %name% ;"))
varValueIf[tok2->next()->varId()] = !VariableValue(0);
else if (Token::Match(tok2, "[;{}.] %name% = %num% ;"))
varValueIf[tok2->next()->varId()] = VariableValue(MathLib::toLongNumber(tok2->strAt(3)));
}
}
if (initif && condVarId > 0U)
variableValue[condVarId] = !condVarValue;
// goto the }
tok = tok->link();
if (!Token::simpleMatch(tok, "} else {")) {
if (initif || possibleInitIf) {
++number_of_if;
if (number_of_if >= 2)
return true;
}
} else {
// goto the {
tok = tok->tokAt(2);
bool possibleInitElse((!alwaysFalse && number_of_if > 0) || suppressErrors);
bool noreturnElse = false;
const bool initelse = !alwaysTrue && checkScopeForVariable(tok->next(), var, &possibleInitElse, &noreturnElse, alloc, membervar);
std::map<unsigned int, VariableValue> varValueElse;
if (!alwaysTrue && !initelse && !noreturnElse) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}.] %var% = - %name% ;"))
varValueElse[tok2->next()->varId()] = !VariableValue(0);
else if (Token::Match(tok2, "[;{}.] %var% = %num% ;"))
varValueElse[tok2->next()->varId()] = VariableValue(MathLib::toLongNumber(tok2->strAt(3)));
}
}
if (initelse && condVarId > 0U && !noreturnIf && !noreturnElse)
variableValue[condVarId] = condVarValue;
// goto the }
tok = tok->link();
if ((alwaysFalse || initif || noreturnIf) &&
(alwaysTrue || initelse || noreturnElse))
return true;
if (initif || initelse || possibleInitElse)
++number_of_if;
if (!initif && !noreturnIf)
variableValue.insert(varValueIf.begin(), varValueIf.end());
if (!initelse && !noreturnElse)
variableValue.insert(varValueElse.begin(), varValueElse.end());
}
}
}
// = { .. }
else if (Token::simpleMatch(tok, "= {")) {
// end token
const Token *end = tok->next()->link();
// If address of variable is taken in the block then bail out
if (var.isPointer() || var.isArray()) {
if (Token::findmatch(tok->tokAt(2), "%varid%", end, var.declarationId()))
return true;
} else if (Token::findmatch(tok->tokAt(2), "& %varid%", end, var.declarationId())) {
return true;
}
// Skip block
tok = end;
continue;
}
// skip sizeof / offsetof
if (Token::Match(tok, "sizeof|typeof|offsetof|decltype ("))
tok = tok->next()->link();
// for/while..
else if (Token::Match(tok, "for|while (") || Token::simpleMatch(tok, "do {")) {
const bool forwhile = Token::Match(tok, "for|while (");
// is variable initialized in for-head (don't report errors yet)?
if (forwhile && checkIfForWhileHead(tok->next(), var, true, false, *alloc, membervar))
return true;
// goto the {
const Token *tok2 = forwhile ? tok->next()->link()->next() : tok->next();
if (tok2 && tok2->str() == "{") {
bool init = checkLoopBody(tok2, var, *alloc, membervar, (number_of_if > 0) || suppressErrors);
// variable is initialized in the loop..
if (init)
return true;
// is variable used in for-head?
bool initcond = false;
if (!suppressErrors) {
const Token *startCond = forwhile ? tok->next() : tok->next()->link()->tokAt(2);
initcond = checkIfForWhileHead(startCond, var, false, bool(number_of_if == 0), *alloc, membervar);
}
// goto "}"
tok = tok2->link();
// do-while => goto ")"
if (!forwhile) {
// Assert that the tokens are '} while ('
if (!Token::simpleMatch(tok, "} while (")) {
if (printDebug)
reportError(tok,Severity::debug,"","assertion failed '} while ('");
break;
}
// Goto ')'
tok = tok->linkAt(2);
if (!tok)
// bailout : invalid code / bad tokenizer
break;
if (initcond)
// variable is initialized in while-condition
return true;
}
}
}
// Unknown or unhandled inner scope
else if (Token::simpleMatch(tok, ") {") || (Token::Match(tok, "%name% {") && tok->str() != "try")) {
if (tok->str() == "struct" || tok->str() == "union") {
tok = tok->linkAt(1);
continue;
}
return true;
}
// bailout if there is ({
if (Token::simpleMatch(tok, "( {")) {
return true;
}
// bailout if there is assembler code or setjmp
if (Token::Match(tok, "asm|setjmp (")) {
return true;
}
// bailout if there is a goto label
if (Token::Match(tok, "[;{}] %name% :")) {
return true;
}
if (tok->str() == "?") {
if (!tok->astOperand2())
return true;
const bool used1 = isVariableUsed(tok->astOperand2()->astOperand1(), var);
const bool used0 = isVariableUsed(tok->astOperand2()->astOperand2(), var);
const bool err = (number_of_if == 0) ? (used1 || used0) : (used1 && used0);
if (err)
uninitvarError(tok, var.nameToken()->str(), *alloc);
// Todo: skip expression if there is no error
return true;
}
if (Token::Match(tok, "return|break|continue|throw|goto")) {
if (noreturn)
*noreturn = true;
tok = tok->next();
while (tok && tok->str() != ";") {
// variable is seen..
if (tok->varId() == var.declarationId()) {
if (!membervar.empty()) {
if (Token::Match(tok, "%name% . %name% ;|%cop%") && tok->strAt(2) == membervar)
uninitStructMemberError(tok, tok->str() + "." + membervar);
else
return true;
}
// Use variable
else if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc))
uninitvarError(tok, tok->str(), *alloc);
else
// assume that variable is assigned
return true;
}
else if (Token::Match(tok, "sizeof|typeof|offsetof|decltype ("))
tok = tok->linkAt(1);
else if (tok->str() == "?") {
if (!tok->astOperand2())
return true;
const bool used1 = isVariableUsed(tok->astOperand2()->astOperand1(), var);
const bool used0 = isVariableUsed(tok->astOperand2()->astOperand2(), var);
const bool err = (number_of_if == 0) ? (used1 || used0) : (used1 && used0);
if (err)
uninitvarError(tok, var.nameToken()->str(), *alloc);
return true;
}
tok = tok->next();
}
return bool(noreturn==nullptr);
}
// variable is seen..
if (tok->varId() == var.declarationId()) {
// calling function that returns uninit data through pointer..
if (var.isPointer() &&
Token::Match(tok->next(), "= %name% (") &&
Token::simpleMatch(tok->linkAt(3), ") ;") &&
_settings->library.returnuninitdata.count(tok->strAt(2)) > 0U) {
*alloc = NO_CTOR_CALL;
continue;
}
if (var.isPointer() && (var.typeStartToken()->isStandardType() || var.typeStartToken()->isEnumType() || (var.type() && var.type()->needInitialization == Type::True)) && Token::simpleMatch(tok->next(), "= new")) {
*alloc = CTOR_CALL;
// type has constructor(s)
if (var.typeScope() && var.typeScope()->numConstructors > 0)
return true;
// standard or enum type: check if new initializes the allocated memory
if (var.typeStartToken()->isStandardType() || var.typeStartToken()->isEnumType()) {
// scalar new with initialization
if (Token::Match(tok->next(), "= new %type% ("))
return true;
// array new
if (Token::Match(tok->next(), "= new %type% [")) {
const Token* tokClosingBracket=tok->linkAt(4);
// array new with initialization
if (tokClosingBracket && Token::simpleMatch(tokClosingBracket->next(), "( )"))
return true;
}
}
continue;
}
if (!membervar.empty()) {
if (isMemberVariableAssignment(tok, membervar)) {
checkRhs(tok, var, *alloc, number_of_if, membervar);
return true;
}
if (isMemberVariableUsage(tok, var.isPointer(), *alloc, membervar))
uninitStructMemberError(tok, tok->str() + "." + membervar);
else if (Token::Match(tok->previous(), "[(,] %name% [,)]"))
return true;
} else {
// Use variable
if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc))
uninitvarError(tok, tok->str(), *alloc);
else {
if (tok->strAt(1) == "=")
checkRhs(tok, var, *alloc, number_of_if, "");
// assume that variable is assigned
return true;
}
}
}
}
return false;
}
