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1729 lines (1533 loc) · 70.5 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2022 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
#include "checkuninitvar.h"
#include "astutils.h"
#include "errorlogger.h"
#include "library.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include "valueflow.h"
#include "checknullpointer.h" // CheckNullPointer::isPointerDeref
#include <algorithm>
#include <cassert>
#include <functional>
#include <initializer_list>
#include <list>
#include <map>
#include <unordered_set>
#include <utility>
#include <vector>
namespace tinyxml2 {
class XMLElement;
}
//---------------------------------------------------------------------------
// CWE ids used:
static const struct CWE CWE_USE_OF_UNINITIALIZED_VARIABLE(457U);
// Register this check class (by creating a static instance of it)
namespace {
CheckUninitVar instance;
}
//---------------------------------------------------------------------------
// get ast parent, skip possible address-of and casts
static const Token *getAstParentSkipPossibleCastAndAddressOf(const Token *vartok, bool *unknown)
{
if (unknown)
*unknown = false;
if (!vartok)
return nullptr;
const Token *parent = vartok->astParent();
while (Token::Match(parent, ".|::"))
parent = parent->astParent();
if (!parent)
return nullptr;
if (parent->isUnaryOp("&"))
parent = parent->astParent();
else if (parent->str() == "&" && vartok == parent->astOperand2() && Token::Match(parent->astOperand1()->previous(), "( %type% )")) {
parent = parent->astParent();
if (unknown)
*unknown = true;
}
while (parent && parent->isCast())
parent = parent->astParent();
return parent;
}
bool CheckUninitVar::diag(const Token* tok)
{
if (!tok)
return true;
while (Token::Match(tok->astParent(), "*|&|."))
tok = tok->astParent();
return !mUninitDiags.insert(tok).second;
}
void CheckUninitVar::check()
{
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
std::set<std::string> arrayTypeDefs;
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "%name% [") && tok->variable() && Token::Match(tok->variable()->typeStartToken(), "%type% %var% ;"))
arrayTypeDefs.insert(tok->variable()->typeStartToken()->str());
}
// check every executable scope
for (const Scope &scope : symbolDatabase->scopeList) {
if (scope.isExecutable()) {
checkScope(&scope, arrayTypeDefs);
}
}
}
void CheckUninitVar::checkScope(const Scope* scope, const std::set<std::string> &arrayTypeDefs)
{
for (const Variable &var : scope->varlist) {
if ((mTokenizer->isCPP() && var.type() && !var.isPointer() && var.type()->needInitialization != Type::NeedInitialization::True) ||
var.isStatic() || var.isExtern() || var.isReference())
continue;
// don't warn for try/catch exception variable
if (var.isThrow())
continue;
if (Token::Match(var.nameToken()->next(), "[({:]"))
continue;
if (Token::Match(var.nameToken(), "%name% =")) { // Variable is initialized, but Rhs might be not
checkRhs(var.nameToken(), var, NO_ALLOC, 0U, emptyString);
continue;
}
if (Token::Match(var.nameToken(), "%name% ) (") && Token::simpleMatch(var.nameToken()->linkAt(2), ") =")) { // Function pointer is initialized, but Rhs might be not
checkRhs(var.nameToken()->linkAt(2)->next(), var, NO_ALLOC, 0U, emptyString);
continue;
}
if (var.isArray() || var.isPointerToArray()) {
const Token *tok = var.nameToken()->next();
if (var.isPointerToArray())
tok = tok->next();
while (Token::simpleMatch(tok->link(), "] ["))
tok = tok->link()->next();
if (Token::Match(tok->link(), "] =|{"))
continue;
}
bool stdtype = mTokenizer->isC() && arrayTypeDefs.find(var.typeStartToken()->str()) == arrayTypeDefs.end();
const Token* tok = var.typeStartToken();
for (; tok != var.nameToken() && tok->str() != "<"; tok = tok->next()) {
if (tok->isStandardType() || tok->isEnumType())
stdtype = true;
}
if (var.isArray() && !stdtype) { // std::array
if (!(var.isStlType() && Token::simpleMatch(var.typeStartToken(), "std :: array") && var.valueType() &&
var.valueType()->containerTypeToken && var.valueType()->containerTypeToken->isStandardType()))
continue;
}
while (tok && tok->str() != ";")
tok = tok->next();
if (!tok)
continue;
if (tok->astParent() && Token::simpleMatch(tok->astParent()->previous(), "for (") &&
checkLoopBody(tok->astParent()->link()->next(), var, var.isArray() ? ARRAY : NO_ALLOC, emptyString, true))
continue;
if (var.isArray()) {
bool init = false;
for (const Token *parent = var.nameToken(); parent; parent = parent->astParent()) {
if (parent->str() == "=") {
init = true;
break;
}
}
if (!init) {
Alloc alloc = ARRAY;
const std::map<nonneg int, VariableValue> variableValue;
checkScopeForVariable(tok, var, nullptr, nullptr, &alloc, emptyString, variableValue);
}
continue;
}
if (stdtype || var.isPointer()) {
Alloc alloc = NO_ALLOC;
const std::map<nonneg int, VariableValue> variableValue;
checkScopeForVariable(tok, var, nullptr, nullptr, &alloc, emptyString, variableValue);
}
if (var.type())
checkStruct(tok, var);
}
if (scope->function) {
for (const Variable &arg : scope->function->argumentList) {
if (arg.declarationId() && Token::Match(arg.typeStartToken(), "%type% * %name% [,)]")) {
// Treat the pointer as initialized until it is assigned by malloc
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "[;{}] %varid% =", arg.declarationId()))
continue;
const Token *allocFuncCallToken = findAllocFuncCallToken(tok->tokAt(2)->astOperand2(), mSettings->library);
if (!allocFuncCallToken)
continue;
const Library::AllocFunc *allocFunc = mSettings->library.getAllocFuncInfo(allocFuncCallToken);
if (!allocFunc || allocFunc->initData)
continue;
if (arg.typeStartToken()->strAt(-1) == "struct" || (arg.type() && arg.type()->isStructType()))
checkStruct(tok, arg);
else if (arg.typeStartToken()->isStandardType() || arg.typeStartToken()->isEnumType()) {
Alloc alloc = NO_ALLOC;
const std::map<nonneg int, VariableValue> variableValue;
checkScopeForVariable(tok->next(), arg, nullptr, nullptr, &alloc, emptyString, variableValue);
}
}
}
}
}
}
void CheckUninitVar::checkStruct(const Token *tok, const Variable &structvar)
{
const Token *typeToken = structvar.typeStartToken();
while (Token::Match(typeToken, "%name% ::"))
typeToken = typeToken->tokAt(2);
const SymbolDatabase * symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope2 : symbolDatabase->classAndStructScopes) {
if (scope2->className == typeToken->str() && scope2->numConstructors == 0U) {
for (const Variable &var : scope2->varlist) {
if (var.isStatic() || var.hasDefault() || var.isArray() ||
(!mTokenizer->isC() && var.isClass() && (!var.type() || var.type()->needInitialization != Type::NeedInitialization::True)))
continue;
// is the variable declared in a inner union?
bool innerunion = false;
for (const Scope *innerScope : scope2->nestedList) {
if (innerScope->type == Scope::eUnion) {
if (var.typeStartToken()->linenr() >= innerScope->bodyStart->linenr() &&
var.typeStartToken()->linenr() <= innerScope->bodyEnd->linenr()) {
innerunion = true;
break;
}
}
}
if (!innerunion) {
Alloc alloc = NO_ALLOC;
const Token *tok2 = tok;
if (tok->str() == "}")
tok2 = tok2->next();
const std::map<nonneg int, VariableValue> variableValue;
checkScopeForVariable(tok2, structvar, nullptr, nullptr, &alloc, var.name(), variableValue);
}
}
}
}
}
static VariableValue operator!(VariableValue v)
{
v.notEqual = !v.notEqual;
return v;
}
static bool operator==(const VariableValue & v, MathLib::bigint i)
{
return v.notEqual ? (i != v.value) : (i == v.value);
}
static bool operator!=(const VariableValue & v, MathLib::bigint i)
{
return v.notEqual ? (i == v.value) : (i != v.value);
}
static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<nonneg int, VariableValue> &variableValue, bool *alwaysTrue, bool *alwaysFalse)
{
if (!tok)
return;
if (tok->hasKnownIntValue()) {
if (tok->getKnownIntValue() == 0)
*alwaysFalse = true;
else
*alwaysTrue = true;
return;
}
if (tok->isName() || tok->str() == ".") {
while (tok && tok->str() == ".")
tok = tok->astOperand2();
const std::map<nonneg int, VariableValue>::const_iterator it = variableValue.find(tok ? tok->varId() : ~0U);
if (it != variableValue.end()) {
*alwaysTrue = (it->second != 0LL);
*alwaysFalse = (it->second == 0LL);
}
}
else if (tok->isComparisonOp()) {
if (variableValue.empty()) {
return;
}
const Token *vartok, *numtok;
if (tok->astOperand2() && tok->astOperand2()->isNumber()) {
vartok = tok->astOperand1();
numtok = tok->astOperand2();
} else if (tok->astOperand1() && tok->astOperand1()->isNumber()) {
vartok = tok->astOperand2();
numtok = tok->astOperand1();
} else {
return;
}
while (vartok && vartok->str() == ".")
vartok = vartok->astOperand2();
const std::map<nonneg int, VariableValue>::const_iterator it = variableValue.find(vartok ? vartok->varId() : ~0U);
if (it == variableValue.end())
return;
if (tok->str() == "==")
*alwaysTrue = (it->second == MathLib::toLongNumber(numtok->str()));
else if (tok->str() == "!=")
*alwaysTrue = (it->second != MathLib::toLongNumber(numtok->str()));
else
return;
*alwaysFalse = !(*alwaysTrue);
}
else if (tok->str() == "!") {
bool t=false,f=false;
conditionAlwaysTrueOrFalse(tok->astOperand1(), variableValue, &t, &f);
if (t || f) {
*alwaysTrue = !t;
*alwaysFalse = !f;
}
}
else if (tok->str() == "||") {
bool t1=false, f1=false;
conditionAlwaysTrueOrFalse(tok->astOperand1(), variableValue, &t1, &f1);
bool t2=false, f2=false;
if (!t1)
conditionAlwaysTrueOrFalse(tok->astOperand2(), variableValue, &t2, &f2);
*alwaysTrue = (t1 || t2);
*alwaysFalse = (f1 && f2);
}
else if (tok->str() == "&&") {
bool t1=false, f1=false;
conditionAlwaysTrueOrFalse(tok->astOperand1(), variableValue, &t1, &f1);
bool t2=false, f2=false;
if (!f1)
conditionAlwaysTrueOrFalse(tok->astOperand2(), variableValue, &t2, &f2);
*alwaysTrue = (t1 && t2);
*alwaysFalse = (f1 || f2);
}
}
static bool isVariableUsed(const Token *tok, const Variable& var)
{
if (!tok)
return false;
if (tok->str() == "&" && !tok->astOperand2())
return false;
if (tok->isConstOp())
return isVariableUsed(tok->astOperand1(),var) || isVariableUsed(tok->astOperand2(),var);
if (tok->varId() != var.declarationId())
return false;
if (!var.isArray())
return true;
const Token *parent = tok->astParent();
while (Token::Match(parent, "[?:]"))
parent = parent->astParent();
// no dereference, then array is not "used"
if (!Token::Match(parent, "*|["))
return false;
const Token *parent2 = parent->astParent();
// TODO: handle function calls. There is a TODO assertion in TestUninitVar::uninitvar_arrays
return !parent2 || parent2->isConstOp() || (parent2->str() == "=" && parent2->astOperand2() == parent);
}
bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var, bool * const possibleInit, bool * const noreturn, Alloc* const alloc, const std::string &membervar, std::map<nonneg int, VariableValue> variableValue)
{
const bool suppressErrors(possibleInit && *possibleInit); // Assume that this is a variable declaration, rather than a fundef
const bool printDebug = mSettings->debugwarnings;
if (possibleInit)
*possibleInit = false;
int number_of_if = 0;
if (var.declarationId() == 0U)
return true;
for (; tok; tok = tok->next()) {
// End of scope..
if (tok->str() == "}") {
if (number_of_if && possibleInit)
*possibleInit = true;
// might be a noreturn function..
if (mTokenizer->isScopeNoReturn(tok)) {
if (noreturn)
*noreturn = true;
return false;
}
break;
}
// Unconditional inner scope, try, lambda, init list
if (tok->str() == "{" && Token::Match(tok->previous(), ",|;|{|}|]|try")) {
bool possibleInitInner = false;
if (checkScopeForVariable(tok->next(), var, &possibleInitInner, noreturn, alloc, membervar, variableValue))
return true;
tok = tok->link();
if (possibleInitInner) {
number_of_if = 1;
if (possibleInit)
*possibleInit = true;
}
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;
// Is variable assigned in condition?
if (!membervar.empty()) {
for (const Token *cond = tok->linkAt(1); cond != tok; cond = cond->previous()) {
if (cond->varId() == var.declarationId() && isMemberVariableAssignment(cond, membervar))
return true;
}
}
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
nonneg int condVarId = 0;
VariableValue condVarValue(0);
const Token *condVarTok = nullptr;
if (alwaysFalse)
;
else if (astIsVariableComparison(tok->next()->astOperand2(), "!=", "0", &condVarTok)) {
const std::map<nonneg int,VariableValue>::const_iterator it = variableValue.find(condVarTok->varId());
if (it != variableValue.cend() && it->second != 0)
return true; // this scope is not fully analysed => return true
else {
condVarId = condVarTok->varId();
condVarValue = !VariableValue(0);
}
} else 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 = (lhs && lhs->hasKnownIntValue()) ? rhs : lhs;
const Token *numtok = (lhs == vartok) ? rhs : lhs;
while (Token::simpleMatch(vartok, "."))
vartok = vartok->astOperand2();
if (vartok && vartok->varId() && numtok && numtok->hasKnownIntValue()) {
const std::map<nonneg int,VariableValue>::const_iterator it = variableValue.find(vartok->varId());
if (it != variableValue.cend() && it->second != numtok->getKnownIntValue())
return true; // this scope is not fully analysed => return true
condVarId = vartok->varId();
condVarValue = VariableValue(numtok->getKnownIntValue());
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, variableValue);
// 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, "bailoutUninitVar", "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<nonneg 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 > 0)
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, variableValue);
std::map<nonneg 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 > 0 && !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.cbegin(), varValueIf.cend());
if (!initelse && !noreturnElse)
variableValue.insert(varValueElse.cbegin(), varValueElse.cend());
}
}
}
// = { .. }
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;
}
const Token *errorToken = nullptr;
visitAstNodes(tok->next(),
[&](const Token *child) {
if (child->isUnaryOp("&"))
return ChildrenToVisit::none;
if (child->str() == "," || child->str() == "{" || child->isConstOp())
return ChildrenToVisit::op1_and_op2;
if (child->str() == "." && Token::Match(child->astOperand1(), "%varid%", var.declarationId()) && child->astOperand2() && child->astOperand2()->str() == membervar) {
errorToken = child;
return ChildrenToVisit::done;
}
return ChildrenToVisit::none;
});
if (errorToken) {
uninitStructMemberError(errorToken->astOperand2(), errorToken->astOperand1()->str() + "." + membervar);
return true;
}
// Skip block
tok = end;
continue;
}
// skip sizeof / offsetof
if (isSizeOfEtc(tok))
tok = tok->linkAt(1);
// 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?
if (forwhile && checkIfForWhileHead(tok->next(), var, tok->str() == "for", false, *alloc, membervar))
return true;
// goto the {
const Token *tok2 = forwhile ? tok->next()->link()->next() : tok->next();
if (tok2 && tok2->str() == "{") {
const 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,emptyString,"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 (!suppressErrors && Token::Match(tok, "%name% . %name%") && tok->strAt(2) == membervar && Token::Match(tok->next()->astParent(), "%cop%|return|throw|?"))
uninitStructMemberError(tok, tok->str() + "." + membervar);
else if (mTokenizer->isCPP() && !suppressErrors && Token::Match(tok, "%name%") && Token::Match(tok->astParent(), "return|throw|?"))
uninitStructMemberError(tok, tok->str() + "." + membervar);
}
// Use variable
else if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc))
uninitvarError(tok, tok->str(), *alloc);
return true;
}
else if (isSizeOfEtc(tok))
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 (noreturn == nullptr);
}
// variable is seen..
if (tok->varId() == var.declarationId()) {
// calling function that returns uninit data through pointer..
if (var.isPointer() && Token::simpleMatch(tok->next(), "=")) {
const Token *rhs = tok->next()->astOperand2();
while (rhs && rhs->isCast())
rhs = rhs->astOperand2() ? rhs->astOperand2() : rhs->astOperand1();
if (rhs && Token::Match(rhs->previous(), "%name% (")) {
const Library::AllocFunc *allocFunc = mSettings->library.getAllocFuncInfo(rhs->astOperand1());
if (allocFunc && !allocFunc->initData) {
*alloc = NO_CTOR_CALL;
continue;
}
}
}
if (mTokenizer->isCPP() && var.isPointer() && (var.typeStartToken()->isStandardType() || var.typeStartToken()->isEnumType() || (var.type() && var.type()->needInitialization == Type::NeedInitialization::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% [") && Token::simpleMatch(tok->linkAt(4), "] ("))
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);
return true;
}
if (Token::Match(tok->previous(), "[(,] %name% [,)]"))
return true;
if (Token::Match(tok->previous(), "= %var% . %var% ;") && membervar == tok->strAt(2))
return true;
} else {
// Use variable
if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc)) {
uninitvarError(tok, tok->str(), *alloc);
return true;
}
else {
const Token *parent = tok;
while (parent->astParent() && ((astIsLHS(parent) && parent->astParent()->str() == "[") || parent->astParent()->isUnaryOp("*"))) {
parent = parent->astParent();
if (parent->str() == "[") {
if (const Token *errorToken = checkExpr(parent->astOperand2(), var, *alloc, number_of_if==0)) {
if (!suppressErrors)
uninitvarError(errorToken, errorToken->expressionString(), *alloc);
return true;
}
}
}
if (Token::simpleMatch(parent->astParent(), "=") && astIsLHS(parent)) {
const Token *eq = parent->astParent();
if (const Token *errorToken = checkExpr(eq->astOperand2(), var, *alloc, number_of_if==0)) {
if (!suppressErrors)
uninitvarError(errorToken, errorToken->expressionString(), *alloc);
return true;
}
}
// assume that variable is assigned
return true;
}
}
}
}
return false;
}
const Token *CheckUninitVar::checkExpr(const Token *tok, const Variable& var, const Alloc alloc, bool known, bool *bailout)
{
if (!tok)
return nullptr;
if (isSizeOfEtc(tok->previous()))
return nullptr;
if (tok->astOperand1()) {
bool bailout1 = false;
const Token *errorToken = checkExpr(tok->astOperand1(), var, alloc, known, &bailout1);
if (bailout && bailout1)
*bailout = true;
if (errorToken)
return errorToken;
if ((bailout1 || !known) && Token::Match(tok, "%oror%|&&|?"))
return nullptr;
}
if (tok->astOperand2())
return checkExpr(tok->astOperand2(), var, alloc, known, bailout);
if (tok->varId() == var.declarationId()) {
const Token *errorToken = isVariableUsage(tok, var.isPointer(), alloc);
if (errorToken)
return errorToken;
else if (bailout)
*bailout = true;
}
return nullptr;
}
bool CheckUninitVar::checkIfForWhileHead(const Token *startparentheses, const Variable& var, bool suppressErrors, bool isuninit, Alloc alloc, const std::string &membervar)
{
const Token * const endpar = startparentheses->link();
if (Token::Match(startparentheses, "( ! %name% %oror%") && startparentheses->tokAt(2)->getValue(0))
suppressErrors = true;
for (const Token *tok = startparentheses->next(); tok && tok != endpar; tok = tok->next()) {
if (tok->varId() == var.declarationId()) {
if (Token::Match(tok, "%name% . %name%")) {
if (membervar.empty())
return true;
if (tok->strAt(2) == membervar) {
if (isMemberVariableAssignment(tok, membervar))
return true;
if (!suppressErrors && isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
uninitStructMemberError(tok, tok->str() + "." + membervar);
}
continue;
}
if (const Token *errorToken = isVariableUsage(tok, var.isPointer(), alloc)) {
if (suppressErrors)
continue;
uninitvarError(errorToken, errorToken->expressionString(), alloc);
}
return true;
}
// skip sizeof / offsetof
if (isSizeOfEtc(tok))
tok = tok->linkAt(1);
if ((!isuninit || !membervar.empty()) && tok->str() == "&&")
suppressErrors = true;
}
return false;
}
/** recursively check loop, return error token */
const Token* CheckUninitVar::checkLoopBodyRecursive(const Token *start, const Variable& var, const Alloc alloc, const std::string &membervar, bool &bailout) const
{
assert(start->str() == "{");
const Token *errorToken = nullptr;
const Token *const end = start->link();
for (const Token *tok = start->next(); tok != end; tok = tok->next()) {
// skip sizeof / offsetof
if (isSizeOfEtc(tok)) {
tok = tok->linkAt(1);
continue;
}
if (Token::Match(tok, "asm ( %str% ) ;")) {
bailout = true;
return nullptr;
}
// for loop; skip third expression until loop body has been analyzed..
if (tok->str() == ";" && Token::simpleMatch(tok->astParent(), ";") && Token::simpleMatch(tok->astParent()->astParent(), "(")) {
const Token *top = tok->astParent()->astParent();
if (!Token::simpleMatch(top->previous(), "for (") || !Token::simpleMatch(top->link(), ") {"))
continue;
const Token *bodyStart = top->link()->next();
const Token *errorToken1 = checkLoopBodyRecursive(bodyStart, var, alloc, membervar, bailout);
if (!errorToken)
errorToken = errorToken1;
if (bailout)
return nullptr;
}
// for loop; skip loop body if there is third expression
if (Token::simpleMatch(tok, ") {") &&
Token::simpleMatch(tok->link()->previous(), "for (") &&
Token::simpleMatch(tok->link()->astOperand2(), ";") &&
Token::simpleMatch(tok->link()->astOperand2()->astOperand2(), ";")) {
tok = tok->linkAt(1);
}
if (tok->str() == "{") {
// switch => bailout
if (tok->scope() && tok->scope()->type == Scope::ScopeType::eSwitch) {
bailout = true;
return nullptr;
}
const Token *errorToken1 = checkLoopBodyRecursive(tok, var, alloc, membervar, bailout);
tok = tok->link();
if (Token::simpleMatch(tok, "} else {")) {
const Token *elseBody = tok->tokAt(2);
const Token *errorToken2 = checkLoopBodyRecursive(elseBody, var, alloc, membervar, bailout);
tok = elseBody->link();
if (errorToken1 && errorToken2)
return errorToken1;
if (errorToken2)
errorToken = errorToken2;
}
if (bailout)
return nullptr;
if (!errorToken)
errorToken = errorToken1;
}
if (tok->varId() != var.declarationId())
continue;
bool conditionalUsage = false;
for (const Token* parent = tok; parent; parent = parent->astParent()) {
if (Token::Match(parent->astParent(), "%oror%|&&|?") && astIsRHS(parent)) {
conditionalUsage = true;
break;
}
}
if (!membervar.empty()) {
if (isMemberVariableAssignment(tok, membervar)) {
bool assign = true;
bool rhs = false;
// Used for tracking if an ")" is inner or outer
const Token *rpar = nullptr;
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
if (tok2->str() == "=")
rhs = true;
// Look at inner expressions but not outer expressions
if (!rpar && tok2->str() == "(")
rpar = tok2->link();
else if (tok2->str() == ")") {
// No rpar => this is an outer right parenthesis
if (!rpar)
break;
if (rpar == tok2)
rpar = nullptr;
}
if (tok2->str() == ";" || (!rpar && tok2->str() == ","))
break;
if (rhs && tok2->varId() == var.declarationId() && isMemberVariableUsage(tok2, var.isPointer(), alloc, membervar)) {
assign = false;
break;
}
}
if (assign) {
bailout = true;