cppcheck/lib/checkuninitvar.cpp at master · napcode/cppcheck · GitHub

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* Cppcheck - A tool for static C/C++ code analysis

* 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 "checknullpointer.h" // CheckNullPointer::isPointerDeref

#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 <tinyxml2.h>

#include <cassert>

#include <cstddef>

#include <list>

#include <map>

#include <stack>

#include <utility>

//---------------------------------------------------------------------------

// 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;

}

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)

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()) {

Alloc alloc = ARRAY;

const std::map<int, VariableValue> variableValue;

bool init = false;

for (const Token *parent = var.nameToken(); parent; parent = parent->astParent()) {

if (parent->str() == "=") {

init = true;

break;

}

if (!init)

checkScopeForVariable(tok, var, nullptr, nullptr, &alloc, emptyString, variableValue);

continue;

}

if (stdtype || var.isPointer()) {

Alloc alloc = NO_ALLOC;

const std::map<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% = %name% (", arg.declarationId()) &&

mSettings->library.returnuninitdata.count(tok->strAt(3)) == 1U) {

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<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();

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<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<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<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 (tok->hasKnownIntValue()) {

if (tok->values().front().intvalue)

*alwaysTrue = true;

else

*alwaysFalse = true;

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<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<int, VariableValue> variableValue)

{

const bool suppressErrors(possibleInit && *possibleInit); // Assume that this is a variable delaratkon, 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 or try..

if (tok->str() == "{" && Token::Match(tok->previous(), ",|;|{|}|try")) {

if (checkScopeForVariable(tok->next(), var, possibleInit, noreturn, alloc, membervar, variableValue))

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;

// 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

int condVarId = 0;

VariableValue condVarValue(0);

const Token *condVarTok = nullptr;

if (alwaysFalse)

;

else if (Token::simpleMatch(tok, "if (") &&

astIsVariableComparison(tok->next()->astOperand2(), "!=", "0", &condVarTok)) {

const std::map<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) {

const std::map<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, 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, "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<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, variableValue);

std::map<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;

}

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 (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?

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,"","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% ;|%cop%") && tok->strAt(2) == membervar)

uninitStructMemberError(tok, tok->str() + "." + membervar);

}

// Use variable

else if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc))

uninitvarError(tok, tok->str(), *alloc);

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 (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->astOperand1();

if (rhs && Token::Match(rhs->previous(), "%name% (") &&

mSettings->library.returnuninitdata.count(rhs->previous()->str()) > 0U) {

*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 {

if (tok->strAt(1) == "=")

checkRhs(tok, var, *alloc, number_of_if, emptyString);

// assume that variable is assigned

return true;

}

return false;

}

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 (isVariableUsage(tok, var.isPointer(), alloc)) {

if (suppressErrors)

continue;

uninitvarError(tok, tok->str(), alloc);

}

return true;

}

if (Token::Match(tok, "sizeof|decltype|offsetof ("))

tok = tok->next()->link();

if ((!isuninit || !membervar.empty()) && tok->str() == "&&")

suppressErrors = true;

}

return false;

}

bool CheckUninitVar::checkLoopBody(const Token *tok, const Variable& var, const Alloc alloc, const std::string &membervar, const bool suppressErrors)

{

const Token *usetok = nullptr;

assert(tok->str() == "{");

for (const Token * const end = tok->link(); tok != end; tok = tok->next()) {

if (Token::Match(tok, "sizeof|typeof (")) {

tok = tok->next()->link();

continue;

}

if (Token::Match(tok, "asm ( %str% ) ;"))

return true;

if (tok->varId() != var.declarationId())

continue;

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)

return true;

}

if (isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))

usetok = tok;

else if (Token::Match(tok->previous(), "[(,] %name% [,)]"))

return true;

} else {

if (isVariableUsage(tok, var.isPointer(), alloc))

usetok = tok;

else if (tok->strAt(1) == "=") {

// Is var used in rhs?

bool rhs = false;

std::stack<const Token *> tokens;

tokens.push(tok->next()->astOperand2());

while (!tokens.empty()) {

const Token *t = tokens.top();

tokens.pop();

if (!t)

continue;

if (t->varId() == var.declarationId()) {

// var is used in rhs

rhs = true;

break;

}

if (Token::simpleMatch(t->previous(),"sizeof ("))

continue;

tokens.push(t->astOperand1());

tokens.push(t->astOperand2());

}

if (!rhs)

return true;

} else {

return true;

}

if (!suppressErrors && usetok) {

if (membervar.empty())

uninitvarError(usetok, usetok->str(), alloc);

else

uninitStructMemberError(usetok, usetok->str() + "." + membervar);

return true;

}

return false;

}

void CheckUninitVar::checkRhs(const Token *tok, const Variable &var, Alloc alloc, nonneg int number_of_if, const std::string &membervar)

{

bool rhs = false;

int indent = 0;

while (nullptr != (tok = tok->next())) {

if (tok->str() == "=")

rhs = true;

else if (rhs && tok->varId() == var.declarationId()) {

if (membervar.empty() && isVariableUsage(tok, var.isPointer(), alloc))

uninitvarError(tok, tok->str(), alloc);

else if (!membervar.empty() && isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))

uninitStructMemberError(tok, tok->str() + "." + membervar);

else if (Token::Match(tok, "%var% ="))

break;

} else if (tok->str() == ";" || (indent==0 && tok->str() == ","))

break;

else if (tok->str() == "(")

++indent;

else if (tok->str() == ")") {

if (indent == 0)

break;

--indent;

} else if (tok->str() == "?" && tok->astOperand2()) {

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);

break;

} else if (Token::simpleMatch(tok, "sizeof ("))

tok = tok->next()->link();

}

bool CheckUninitVar::isVariableUsage(const Token *vartok, bool pointer, Alloc alloc, int indirect) const

{

if (!pointer && Token::Match(vartok, "%name% ("))

return false;

if (alloc == NO_ALLOC && (Token::Match(vartok->previous(), "return|delete %var% !!=") || (vartok->strAt(-1) == "]" && vartok->linkAt(-1)->strAt(-1) == "delete")))

return true;

// Passing variable to typeof/__alignof__

if (Token::Match(vartok->tokAt(-3), "typeof|__alignof__ ( * %name%"))

return false;

// Accessing Rvalue member using "." or "->"

if (Token::Match(vartok->previous(), "!!& %var% .")) {

// Is struct member passed to function?

if (!pointer)

return false;

if (alloc != CTOR_CALL && Token::Match(vartok, "%name% . %name% ("))

return true;

bool assignment = false;

const Token* parent = vartok->astParent();

while (parent) {

if (parent->str() == "=") {

assignment = true;

break;

}

if (alloc != NO_ALLOC && parent->str() == "(") {

if (!mSettings->library.isFunctionConst(parent->strAt(-1), true)) {

assignment = true;

break;

}

parent = parent->astParent();

}

if (!assignment)

return true;

}

// Passing variable to function..

{

bool unknown = false;

const Token *possibleParent = getAstParentSkipPossibleCastAndAddressOf(vartok, &unknown);

if (possibleParent && possibleParent->isUnaryOp("*")) {

while (possibleParent && possibleParent->isUnaryOp("*"))

possibleParent = getAstParentSkipPossibleCastAndAddressOf(possibleParent, &unknown);

if (possibleParent && Token::Match(possibleParent->previous(), "decltype|sizeof ("))

return false;

if (possibleParent && isLikelyStreamRead(mTokenizer->isCPP(), possibleParent))

return false;

}

if (Token::Match(possibleParent, "[(,]")) {

if (unknown)

return false; // TODO: output some info message?

const int use = isFunctionParUsage(vartok, pointer, alloc, indirect);

if (use >= 0)

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cppcheck/lib/checkuninitvar.cpp at master · napcode/cppcheck · GitHub

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