1083 lines
39 KiB
C++
1083 lines
39 KiB
C++
/*
|
|
* Cppcheck - A tool for static C/C++ code analysis
|
|
* Copyright (C) 2007-2012 Daniel Marjamäki and 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 "checkunusedvar.h"
|
|
#include "symboldatabase.h"
|
|
|
|
//---------------------------------------------------------------------------
|
|
|
|
// Register this check class (by creating a static instance of it)
|
|
namespace {
|
|
CheckUnusedVar instance;
|
|
}
|
|
|
|
/**
|
|
* @brief This class is used create a list of variables within a function.
|
|
*/
|
|
class Variables {
|
|
public:
|
|
enum VariableType { standard, array, pointer, reference, pointerArray, referenceArray, pointerPointer, none };
|
|
|
|
/** Store information about variable usage */
|
|
class VariableUsage {
|
|
public:
|
|
VariableUsage(const Token *name = 0,
|
|
VariableType type = standard,
|
|
const Scope *scope = NULL,
|
|
bool read = false,
|
|
bool write = false,
|
|
bool modified = false,
|
|
bool allocateMemory = false) :
|
|
_name(name),
|
|
_type(type),
|
|
_scope(scope),
|
|
_read(read),
|
|
_write(write),
|
|
_modified(modified),
|
|
_allocateMemory(allocateMemory) {
|
|
}
|
|
|
|
/** variable is used.. set both read+write */
|
|
void use() {
|
|
_read = true;
|
|
_write = true;
|
|
}
|
|
|
|
/** is variable unused? */
|
|
bool unused() const {
|
|
return (_read == false && _write == false);
|
|
}
|
|
|
|
const Token *_name;
|
|
VariableType _type;
|
|
const Scope *_scope;
|
|
bool _read;
|
|
bool _write;
|
|
bool _modified; // read/modify/write
|
|
bool _allocateMemory;
|
|
std::set<unsigned int> _aliases;
|
|
std::set<const Scope*> _assignments;
|
|
};
|
|
|
|
typedef std::map<unsigned int, VariableUsage> VariableMap;
|
|
|
|
void clear() {
|
|
_varUsage.clear();
|
|
}
|
|
const VariableMap &varUsage() const {
|
|
return _varUsage;
|
|
}
|
|
void addVar(const Token *name, VariableType type, const Scope *scope, bool write_);
|
|
void allocateMemory(unsigned int varid);
|
|
void read(unsigned int varid);
|
|
void readAliases(unsigned int varid);
|
|
void readAll(unsigned int varid);
|
|
void write(unsigned int varid);
|
|
void writeAliases(unsigned int varid);
|
|
void writeAll(unsigned int varid);
|
|
void use(unsigned int varid);
|
|
void modified(unsigned int varid);
|
|
VariableUsage *find(unsigned int varid);
|
|
void alias(unsigned int varid1, unsigned int varid2, bool replace);
|
|
void erase(unsigned int varid) {
|
|
_varUsage.erase(varid);
|
|
}
|
|
void eraseAliases(unsigned int varid);
|
|
void eraseAll(unsigned int varid);
|
|
void clearAliases(unsigned int varid);
|
|
|
|
private:
|
|
VariableMap _varUsage;
|
|
};
|
|
|
|
|
|
/**
|
|
* Alias the 2 given variables. Either replace the existing aliases if
|
|
* they exist or merge them. You would replace an existing alias when this
|
|
* assignment is in the same scope as the previous assignment. You might
|
|
* merge the aliases when this assignment is in a different scope from the
|
|
* previous assignment depending on the relationship of the 2 scopes.
|
|
*/
|
|
void Variables::alias(unsigned int varid1, unsigned int varid2, bool replace)
|
|
{
|
|
VariableUsage *var1 = find(varid1);
|
|
VariableUsage *var2 = find(varid2);
|
|
|
|
// alias to self
|
|
if (varid1 == varid2) {
|
|
if (var1)
|
|
var1->use();
|
|
return;
|
|
}
|
|
|
|
if (replace) {
|
|
// remove var1 from all aliases
|
|
for (std::set<unsigned int>::iterator i = var1->_aliases.begin(); i != var1->_aliases.end(); ++i) {
|
|
VariableUsage *temp = find(*i);
|
|
|
|
if (temp)
|
|
temp->_aliases.erase(var1->_name->varId());
|
|
}
|
|
|
|
// remove all aliases from var1
|
|
var1->_aliases.clear();
|
|
}
|
|
|
|
// var1 gets all var2s aliases
|
|
for (std::set<unsigned int>::iterator i = var2->_aliases.begin(); i != var2->_aliases.end(); ++i) {
|
|
if (*i != varid1)
|
|
var1->_aliases.insert(*i);
|
|
}
|
|
|
|
// var2 is an alias of var1
|
|
var2->_aliases.insert(varid1);
|
|
var1->_aliases.insert(varid2);
|
|
|
|
if (var2->_type == Variables::pointer)
|
|
var2->_read = true;
|
|
}
|
|
|
|
void Variables::clearAliases(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
// remove usage from all aliases
|
|
std::set<unsigned int>::iterator i;
|
|
|
|
for (i = usage->_aliases.begin(); i != usage->_aliases.end(); ++i) {
|
|
VariableUsage *temp = find(*i);
|
|
|
|
if (temp)
|
|
temp->_aliases.erase(usage->_name->varId());
|
|
}
|
|
|
|
// remove all aliases from usage
|
|
usage->_aliases.clear();
|
|
}
|
|
}
|
|
|
|
void Variables::eraseAliases(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases)
|
|
erase(*aliases);
|
|
}
|
|
}
|
|
|
|
void Variables::eraseAll(unsigned int varid)
|
|
{
|
|
eraseAliases(varid);
|
|
erase(varid);
|
|
}
|
|
|
|
void Variables::addVar(const Token *name,
|
|
VariableType type,
|
|
const Scope *scope,
|
|
bool write_)
|
|
{
|
|
if (name->varId() > 0)
|
|
_varUsage.insert(std::make_pair(name->varId(), VariableUsage(name, type, scope, false, write_, false)));
|
|
}
|
|
|
|
void Variables::allocateMemory(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage)
|
|
usage->_allocateMemory = true;
|
|
}
|
|
|
|
void Variables::read(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage)
|
|
usage->_read = true;
|
|
}
|
|
|
|
void Variables::readAliases(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
|
|
VariableUsage *aliased = find(*aliases);
|
|
|
|
if (aliased)
|
|
aliased->_read = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Variables::readAll(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
usage->_read = true;
|
|
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
|
|
VariableUsage *aliased = find(*aliases);
|
|
|
|
if (aliased)
|
|
aliased->_read = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Variables::write(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage)
|
|
usage->_write = true;
|
|
}
|
|
|
|
void Variables::writeAliases(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
|
|
VariableUsage *aliased = find(*aliases);
|
|
|
|
if (aliased)
|
|
aliased->_write = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Variables::writeAll(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
usage->_write = true;
|
|
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
|
|
VariableUsage *aliased = find(*aliases);
|
|
|
|
if (aliased)
|
|
aliased->_write = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Variables::use(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
usage->use();
|
|
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
|
|
VariableUsage *aliased = find(*aliases);
|
|
|
|
if (aliased)
|
|
aliased->use();
|
|
}
|
|
}
|
|
}
|
|
|
|
void Variables::modified(unsigned int varid)
|
|
{
|
|
VariableUsage *usage = find(varid);
|
|
|
|
if (usage) {
|
|
usage->_modified = true;
|
|
|
|
std::set<unsigned int>::iterator aliases;
|
|
|
|
for (aliases = usage->_aliases.begin(); aliases != usage->_aliases.end(); ++aliases) {
|
|
VariableUsage *aliased = find(*aliases);
|
|
|
|
if (aliased)
|
|
aliased->_modified = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
Variables::VariableUsage *Variables::find(unsigned int varid)
|
|
{
|
|
if (varid) {
|
|
VariableMap::iterator i = _varUsage.find(varid);
|
|
if (i != _varUsage.end())
|
|
return &i->second;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static const Token* doAssignment(Variables &variables, const Token *tok, bool dereference, const Scope *scope)
|
|
{
|
|
// a = a + b;
|
|
if (Token::Match(tok, "%var% = %var% !!;") && tok->varId() == tok->tokAt(2)->varId()) {
|
|
return tok->tokAt(2);
|
|
}
|
|
|
|
const Token* const tokOld = tok;
|
|
|
|
// check for aliased variable
|
|
const unsigned int varid1 = tok->varId();
|
|
Variables::VariableUsage *var1 = variables.find(varid1);
|
|
|
|
if (var1) {
|
|
// jump behind '='
|
|
tok = tok->next();
|
|
while (tok->str() != "=")
|
|
tok = tok->next();
|
|
tok = tok->next();
|
|
|
|
if (Token::Match(tok, "&| %var%") ||
|
|
Token::Match(tok, "( const| struct|union| %type% *| ) &| %var%") ||
|
|
Token::Match(tok, "( const| struct|union| %type% *| ) ( &| %var%") ||
|
|
Token::Match(tok->next(), "< const| struct|union| %type% *| > ( &| %var%")) {
|
|
bool addressOf = false;
|
|
|
|
if (Token::Match(tok, "%var% ."))
|
|
variables.use(tok->varId()); // use = read + write
|
|
|
|
// check for C style cast
|
|
if (tok->str() == "(") {
|
|
tok = tok->next();
|
|
if (tok->str() == "const")
|
|
tok = tok->next();
|
|
|
|
if (Token::Match(tok, "struct|union"))
|
|
tok = tok->next();
|
|
|
|
tok = tok->next();
|
|
if (tok->str() == "*")
|
|
tok = tok->next();
|
|
|
|
tok = tok->next();
|
|
if (tok->str() == "&") {
|
|
addressOf = true;
|
|
tok = tok->next();
|
|
} else if (tok->str() == "(") {
|
|
tok = tok->next();
|
|
if (tok->str() == "&") {
|
|
addressOf = true;
|
|
tok = tok->next();
|
|
}
|
|
}
|
|
}
|
|
|
|
// check for C++ style cast
|
|
else if (tok->str().find("cast") != std::string::npos &&
|
|
tok->strAt(1) == "<") {
|
|
tok = tok->tokAt(2);
|
|
if (tok->str() == "const")
|
|
tok = tok->next();
|
|
|
|
if (Token::Match(tok, "struct|union"))
|
|
tok = tok->next();
|
|
|
|
tok = tok->next();
|
|
if (tok->str() == "*")
|
|
tok = tok->next();
|
|
|
|
tok = tok->tokAt(2);
|
|
if (tok->str() == "&") {
|
|
addressOf = true;
|
|
tok = tok->next();
|
|
}
|
|
}
|
|
|
|
// no cast, no ?
|
|
else if (!Token::Match(tok, "%var% ?")) {
|
|
if (tok->str() == "&") {
|
|
addressOf = true;
|
|
tok = tok->next();
|
|
} else if (tok->str() == "new")
|
|
return tokOld;
|
|
}
|
|
|
|
// check if variable is local
|
|
unsigned int varid2 = tok->varId();
|
|
Variables::VariableUsage* var2 = variables.find(varid2);
|
|
|
|
if (var2) { // local variable (alias or read it)
|
|
if (var1->_type == Variables::pointer) {
|
|
if (dereference)
|
|
variables.read(varid2);
|
|
else {
|
|
if (addressOf ||
|
|
var2->_type == Variables::array ||
|
|
var2->_type == Variables::pointer) {
|
|
bool replace = true;
|
|
|
|
// check if variable declared in same scope
|
|
if (scope == var1->_scope)
|
|
replace = true;
|
|
|
|
// not in same scope as declaration
|
|
else {
|
|
// no other assignment in this scope
|
|
if (var1->_assignments.find(scope) == var1->_assignments.end()) {
|
|
// nothing to replace
|
|
if (var1->_assignments.empty())
|
|
replace = false;
|
|
|
|
// this variable has previous assignments
|
|
else {
|
|
/**
|
|
* @todo determine if existing aliases should be replaced or merged
|
|
*/
|
|
|
|
replace = false;
|
|
}
|
|
}
|
|
|
|
// assignment in this scope
|
|
else {
|
|
// replace when only one other assignment, merge them otherwise
|
|
replace = (var1->_assignments.size() == 1);
|
|
}
|
|
}
|
|
|
|
variables.alias(varid1, varid2, replace);
|
|
} else if (tok->strAt(1) == "?") {
|
|
if (var2->_type == Variables::reference)
|
|
variables.readAliases(varid2);
|
|
else
|
|
variables.read(varid2);
|
|
}
|
|
}
|
|
} else if (var1->_type == Variables::reference) {
|
|
variables.alias(varid1, varid2, true);
|
|
} else {
|
|
if (var2->_type == Variables::pointer && tok->strAt(1) == "[")
|
|
variables.readAliases(varid2);
|
|
|
|
variables.read(varid2);
|
|
}
|
|
} else { // not a local variable (or an unsupported local variable)
|
|
if (var1->_type == Variables::pointer && !dereference) {
|
|
// check if variable declaration is in this scope
|
|
if (var1->_scope == scope)
|
|
variables.clearAliases(varid1);
|
|
else {
|
|
// no other assignment in this scope
|
|
if (var1->_assignments.find(scope) == var1->_assignments.end()) {
|
|
/**
|
|
* @todo determine if existing aliases should be discarded
|
|
*/
|
|
}
|
|
|
|
// this assignment replaces the last assignment in this scope
|
|
else {
|
|
// aliased variables in a larger scope are not supported
|
|
// remove all aliases
|
|
variables.clearAliases(varid1);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
} else
|
|
tok = tokOld;
|
|
|
|
var1->_assignments.insert(scope);
|
|
}
|
|
|
|
// check for alias to struct member
|
|
// char c[10]; a.b = c;
|
|
else if (Token::Match(tok->tokAt(-2), "%var% .")) {
|
|
if (Token::Match(tok->tokAt(2), "%var%")) {
|
|
unsigned int varid2 = tok->tokAt(2)->varId();
|
|
Variables::VariableUsage *var2 = variables.find(varid2);
|
|
|
|
// struct member aliased to local variable
|
|
if (var2 && (var2->_type == Variables::array ||
|
|
var2->_type == Variables::pointer)) {
|
|
// erase aliased variable and all variables that alias it
|
|
// to prevent false positives
|
|
variables.eraseAll(varid2);
|
|
}
|
|
}
|
|
}
|
|
|
|
return tok;
|
|
}
|
|
|
|
static bool isRecordTypeWithoutSideEffects(const Variable& var)
|
|
{
|
|
// a type that has no side effects (no constructors and no members with constructors)
|
|
/** @todo false negative: check base class for side effects */
|
|
/** @todo false negative: check constructors for side effects */
|
|
if (var.type() && var.type()->numConstructors == 0 &&
|
|
(var.type()->varlist.empty() || var.type()->needInitialization == Scope::True) &&
|
|
var.type()->derivedFrom.empty())
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static bool isPartOfClassStructUnion(const Token* tok)
|
|
{
|
|
for (; tok; tok = tok->previous()) {
|
|
if (tok->str() == "}" || tok->str() == ")")
|
|
tok = tok->link();
|
|
else if (tok->str() == "(")
|
|
return(false);
|
|
else if (tok->str() == "{") {
|
|
return(tok->strAt(-1) == "struct" || tok->strAt(-2) == "struct" || tok->strAt(-1) == "class" || tok->strAt(-2) == "class" || tok->strAt(-1) == "union" || tok->strAt(-2) == "union");
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Skip [ .. ]
|
|
static const Token * skipBrackets(const Token *tok)
|
|
{
|
|
while (tok && tok->str() == "[")
|
|
tok = tok->link()->next();
|
|
return tok;
|
|
}
|
|
|
|
|
|
// Skip [ .. ] . x
|
|
static const Token * skipBracketsAndMembers(const Token *tok)
|
|
{
|
|
while (tok) {
|
|
if (tok->str() == "[")
|
|
tok = tok->link()->next();
|
|
else if (Token::Match(tok, ". %var%"))
|
|
tok = tok->tokAt(2);
|
|
else
|
|
break;
|
|
}
|
|
return tok;
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Usage of function variables
|
|
//---------------------------------------------------------------------------
|
|
void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const scope, Variables& variables)
|
|
{
|
|
// Find declarations if the scope is executable..
|
|
if (scope->type != Scope::eClass && scope->type != Scope::eUnion && scope->type != Scope::eStruct) {
|
|
// Find declarations
|
|
for (std::list<Variable>::const_iterator i = scope->varlist.begin(); i != scope->varlist.end(); ++i) {
|
|
if (i->isThrow())
|
|
continue;
|
|
Variables::VariableType type = Variables::none;
|
|
if (i->isArray() && (i->nameToken()->previous()->str() == "*" || i->nameToken()->strAt(-2) == "*"))
|
|
type = Variables::pointerArray;
|
|
else if (i->isArray() && i->nameToken()->previous()->str() == "&")
|
|
type = Variables::referenceArray;
|
|
else if (i->isArray())
|
|
type = Variables::array;
|
|
else if (i->isReference())
|
|
type = Variables::reference;
|
|
else if (i->nameToken()->previous()->str() == "*" && i->nameToken()->strAt(-2) == "*")
|
|
type = Variables::pointerPointer;
|
|
else if (i->isPointer())
|
|
type = Variables::pointer;
|
|
else if (i->typeEndToken()->isStandardType() || isRecordTypeWithoutSideEffects(*i) || Token::simpleMatch(i->nameToken()->tokAt(-3), "std :: string"))
|
|
type = Variables::standard;
|
|
if (type == Variables::none || isPartOfClassStructUnion(i->typeStartToken()))
|
|
continue;
|
|
const Token* defValTok = i->nameToken()->next();
|
|
for (; defValTok; defValTok = defValTok->next()) {
|
|
if (defValTok->str() == "[")
|
|
defValTok = defValTok->link();
|
|
else if (defValTok->str() == "(" || defValTok->str() == "=") {
|
|
variables.addVar(i->nameToken(), type, scope, true);
|
|
break;
|
|
} else if (defValTok->str() == ";" || defValTok->str() == "," || defValTok->str() == ")") {
|
|
variables.addVar(i->nameToken(), type, scope, i->isStatic());
|
|
break;
|
|
}
|
|
}
|
|
if (i->isArray() && i->isClass()) // Array of class/struct members. Initialized by ctor.
|
|
variables.write(i->varId());
|
|
if (i->isArray() && Token::Match(i->nameToken(), "%var% [ %var% ]")) // Array index variable read.
|
|
variables.read(i->nameToken()->tokAt(2)->varId());
|
|
|
|
if (defValTok && defValTok->str() == "=") {
|
|
if (defValTok->next() && defValTok->next()->str() == "{") {
|
|
for (const Token* tok = defValTok; tok && tok != defValTok->linkAt(1); tok = tok->next())
|
|
if (Token::Match(tok, "%var%")) // Variables used to initialize the array read.
|
|
variables.read(tok->varId());
|
|
} else
|
|
doAssignment(variables, i->nameToken(), false, scope);
|
|
} else if (Token::Match(defValTok, "( %var% )")) // Variables used to initialize the variable read.
|
|
variables.readAll(defValTok->next()->varId()); // ReadAll?
|
|
}
|
|
}
|
|
|
|
// Check variable usage
|
|
for (const Token *tok = scope->classDef->next(); tok && tok != scope->classEnd; tok = tok->next()) {
|
|
if (tok->str() == "for") {
|
|
for (std::list<Scope*>::const_iterator i = scope->nestedList.begin(); i != scope->nestedList.end(); ++i) {
|
|
if ((*i)->classDef == tok) { // Find associated scope
|
|
checkFunctionVariableUsage_iterateScopes(*i, variables); // Scan child scope
|
|
tok = (*i)->classStart->link();
|
|
break;
|
|
}
|
|
}
|
|
if (!tok)
|
|
break;
|
|
}
|
|
if (tok->str() == "{") {
|
|
for (std::list<Scope*>::const_iterator i = scope->nestedList.begin(); i != scope->nestedList.end(); ++i) {
|
|
if ((*i)->classStart == tok) { // Find associated scope
|
|
checkFunctionVariableUsage_iterateScopes(*i, variables); // Scan child scope
|
|
tok = tok->link();
|
|
break;
|
|
}
|
|
}
|
|
if (!tok)
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok, "asm ( %str% )")) {
|
|
variables.clear();
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok, "%type% const| *|&| const| *| const| %var% [;=[(]")) { // Declaration: Skip
|
|
// Before a declaration there should be ;{}
|
|
const Token *prev = tok;
|
|
while (prev && prev->isName() && prev->str() != "return" && prev->str() != "throw")
|
|
prev = prev->previous();
|
|
if (Token::Match(prev, "[;{}]")) {
|
|
|
|
tok = tok->next();
|
|
while (Token::Match(tok, "const|*|&"))
|
|
tok = tok->next();
|
|
tok = Token::findmatch(tok, "[;=[(]");
|
|
if (tok && Token::Match(tok, "( %var% )")) // Simple initialization through copy ctor
|
|
tok = tok->next();
|
|
else if (tok && Token::Match(tok, "= %var% ;")) // Simple initialization
|
|
tok = tok->next();
|
|
if (!tok)
|
|
break;
|
|
}
|
|
}
|
|
// Freeing memory (not considered "using" the pointer if it was also allocated in this function)
|
|
if (Token::Match(tok, "free|g_free|kfree|vfree ( %var% )") ||
|
|
Token::Match(tok, "delete %var% ;") ||
|
|
Token::Match(tok, "delete [ ] %var% ;")) {
|
|
unsigned int varid = 0;
|
|
if (tok->str() != "delete") {
|
|
varid = tok->tokAt(2)->varId();
|
|
tok = tok->tokAt(3);
|
|
} else if (tok->strAt(1) == "[") {
|
|
varid = tok->tokAt(3)->varId();
|
|
tok = tok->tokAt(3);
|
|
} else {
|
|
varid = tok->next()->varId();
|
|
tok = tok->next();
|
|
}
|
|
|
|
Variables::VariableUsage *var = variables.find(varid);
|
|
if (var && !var->_allocateMemory) {
|
|
variables.readAll(varid);
|
|
}
|
|
}
|
|
|
|
else if (Token::Match(tok, "return|throw")) {
|
|
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
|
|
if (tok2->varId())
|
|
variables.readAll(tok2->varId());
|
|
else if (tok2->str() == ";")
|
|
break;
|
|
}
|
|
}
|
|
|
|
// assignment
|
|
else if (!Token::Match(tok->tokAt(-2), "[;{}.] %var% (") &&
|
|
(Token::Match(tok, "*| (| ++|--| %var% ++|--| )| =") ||
|
|
Token::Match(tok, "*| ( const| %type% *| ) %var% ="))) {
|
|
bool dereference = false;
|
|
bool pre = false;
|
|
bool post = false;
|
|
|
|
if (tok->str() == "*") {
|
|
dereference = true;
|
|
tok = tok->next();
|
|
}
|
|
|
|
if (Token::Match(tok, "( const| %type% *| ) %var% ="))
|
|
tok = tok->link()->next();
|
|
|
|
else if (tok->str() == "(")
|
|
tok = tok->next();
|
|
|
|
if (Token::Match(tok, "++|--")) {
|
|
pre = true;
|
|
tok = tok->next();
|
|
}
|
|
|
|
if (Token::Match(tok->next(), "++|--"))
|
|
post = true;
|
|
|
|
const unsigned int varid1 = tok->varId();
|
|
const Token *start = tok;
|
|
|
|
tok = doAssignment(variables, tok, dereference, scope);
|
|
|
|
if (pre || post)
|
|
variables.use(varid1);
|
|
|
|
if (dereference) {
|
|
Variables::VariableUsage *var = variables.find(varid1);
|
|
if (var && var->_type == Variables::array)
|
|
variables.write(varid1);
|
|
variables.writeAliases(varid1);
|
|
variables.read(varid1);
|
|
} else {
|
|
Variables::VariableUsage *var = variables.find(varid1);
|
|
if (var && var->_type == Variables::reference) {
|
|
variables.writeAliases(varid1);
|
|
variables.read(varid1);
|
|
}
|
|
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
|
|
else if (var && var->_type == Variables::pointer &&
|
|
Token::Match(start, "%var% = new|malloc|calloc|kmalloc|kzalloc|kcalloc|strdup|strndup|vmalloc|g_new0|g_try_new|g_new|g_malloc|g_malloc0|g_try_malloc|g_try_malloc0|g_strdup|g_strndup|g_strdup_printf")) {
|
|
bool allocate = true;
|
|
|
|
if (start->strAt(2) == "new") {
|
|
const Token *type = start->tokAt(3);
|
|
|
|
// skip nothrow
|
|
if (Token::simpleMatch(type, "( nothrow )") ||
|
|
Token::simpleMatch(type, "( std :: nothrow )"))
|
|
type = type->link()->next();
|
|
|
|
// is it a user defined type?
|
|
if (!type->isStandardType()) {
|
|
const Variable* variable = _tokenizer->getSymbolDatabase()->getVariableFromVarId(start->varId());
|
|
if (!variable || !isRecordTypeWithoutSideEffects(*variable))
|
|
allocate = false;
|
|
}
|
|
}
|
|
|
|
if (allocate)
|
|
variables.allocateMemory(varid1);
|
|
else
|
|
variables.write(varid1);
|
|
} else if (varid1 && Token::Match(tok, "%varid% .", varid1)) {
|
|
variables.use(varid1);
|
|
} else {
|
|
variables.write(varid1);
|
|
}
|
|
|
|
Variables::VariableUsage *var2 = variables.find(tok->varId());
|
|
if (var2) {
|
|
if (var2->_type == Variables::reference) {
|
|
variables.writeAliases(tok->varId());
|
|
variables.read(tok->varId());
|
|
} else if (tok->varId() != varid1 && Token::Match(tok, "%var% ."))
|
|
variables.read(tok->varId());
|
|
else if (tok->varId() != varid1 &&
|
|
var2->_type == Variables::standard &&
|
|
tok->strAt(-1) != "&")
|
|
variables.use(tok->varId());
|
|
}
|
|
}
|
|
|
|
const Token * const equal = skipBracketsAndMembers(tok->next());
|
|
|
|
// checked for chained assignments
|
|
if (tok != start && equal && equal->str() == "=") {
|
|
Variables::VariableUsage *var = variables.find(tok->varId());
|
|
|
|
if (var && var->_type != Variables::reference)
|
|
var->_read = true;
|
|
|
|
tok = tok->previous();
|
|
}
|
|
}
|
|
|
|
// assignment
|
|
else if (Token::Match(tok, "%var% [") && Token::simpleMatch(skipBracketsAndMembers(tok->next()), "=")) {
|
|
unsigned int varid = tok->varId();
|
|
const Variables::VariableUsage *var = variables.find(varid);
|
|
|
|
if (var) {
|
|
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
|
|
if (var->_type == Variables::pointer &&
|
|
Token::Match(skipBrackets(tok->next()), "= new|malloc|calloc|kmalloc|kzalloc|kcalloc|strdup|strndup|vmalloc|g_new0|g_try_new|g_new|g_malloc|g_malloc0|g_try_malloc|g_try_malloc0|g_strdup|g_strndup|g_strdup_printf")) {
|
|
variables.allocateMemory(varid);
|
|
} else if (var->_type == Variables::pointer || var->_type == Variables::reference) {
|
|
variables.read(varid);
|
|
variables.writeAliases(varid);
|
|
} else
|
|
variables.writeAll(varid);
|
|
}
|
|
}
|
|
|
|
else if (Token::Match(tok, "& %var%")) {
|
|
if (tok->previous()->isName() || tok->previous()->isNumber()) { // bitop
|
|
variables.read(tok->next()->varId());
|
|
} else // addressof
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
} else if (Token::Match(tok, ">> %var%"))
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
else if (Token::Match(tok, "%var% >>|&") && Token::Match(tok->previous(), "[{};:]"))
|
|
variables.read(tok->varId());
|
|
|
|
// function parameter
|
|
else if (Token::Match(tok, "[(,] %var% ["))
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
else if (Token::Match(tok, "[(,] %var% [,)]") && tok->previous()->str() != "*") {
|
|
variables.use(tok->next()->varId()); // use = read + write
|
|
} else if (Token::Match(tok, "[(,] (") &&
|
|
Token::Match(tok->next()->link(), ") %var% [,)]"))
|
|
variables.use(tok->next()->link()->next()->varId()); // use = read + write
|
|
|
|
// function
|
|
else if (Token::Match(tok, "%var% (")) {
|
|
variables.read(tok->varId());
|
|
if (Token::Match(tok->tokAt(2), "%var% ="))
|
|
variables.read(tok->tokAt(2)->varId());
|
|
}
|
|
|
|
else if (Token::Match(tok, "[{,] %var% [,}]"))
|
|
variables.read(tok->next()->varId());
|
|
|
|
else if (Token::Match(tok, "%var% ."))
|
|
variables.use(tok->varId()); // use = read + write
|
|
|
|
else if (tok->isExtendedOp() &&
|
|
Token::Match(tok->next(), "%var%") && !Token::Match(tok->next(), "true|false|new") && tok->strAt(2) != "=")
|
|
variables.readAll(tok->next()->varId());
|
|
|
|
else if (Token::Match(tok, "%var%") && (tok->next()->str() == ")" || tok->next()->isExtendedOp()))
|
|
variables.readAll(tok->varId());
|
|
|
|
else if (Token::Match(tok, "%var% ;") && Token::Match(tok->previous(), "[;{}:]"))
|
|
variables.readAll(tok->varId());
|
|
|
|
else if (Token::Match(tok, "++|-- %var%")) {
|
|
if (!Token::Match(tok->previous(), "[;{}:]"))
|
|
variables.use(tok->next()->varId());
|
|
else
|
|
variables.modified(tok->next()->varId());
|
|
}
|
|
|
|
else if (Token::Match(tok, "%var% ++|--")) {
|
|
if (!Token::Match(tok->previous(), "[;{}:]"))
|
|
variables.use(tok->varId());
|
|
else
|
|
variables.modified(tok->varId());
|
|
}
|
|
|
|
else if (tok->isAssignmentOp()) {
|
|
for (const Token *tok2 = tok->next(); tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
|
|
if (tok2->varId()) {
|
|
variables.read(tok2->varId());
|
|
if (tok2->next()->isAssignmentOp())
|
|
variables.write(tok2->varId());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUnusedVar::checkFunctionVariableUsage()
|
|
{
|
|
if (!_settings->isEnabled("style"))
|
|
return;
|
|
|
|
// Parse all executing scopes..
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
|
|
// only check functions
|
|
if (scope->type != Scope::eFunction)
|
|
continue;
|
|
|
|
// varId, usage {read, write, modified}
|
|
Variables variables;
|
|
|
|
checkFunctionVariableUsage_iterateScopes(&*scope, variables);
|
|
|
|
|
|
// Check usage of all variables in the current scope..
|
|
for (Variables::VariableMap::const_iterator it = variables.varUsage().begin(); it != variables.varUsage().end(); ++it) {
|
|
const Variables::VariableUsage &usage = it->second;
|
|
const std::string &varname = usage._name->str();
|
|
|
|
// variable has been marked as unused so ignore it
|
|
if (usage._name->isUnused())
|
|
continue;
|
|
|
|
// skip things that are only partially implemented to prevent false positives
|
|
if (usage._type == Variables::pointerPointer ||
|
|
usage._type == Variables::pointerArray ||
|
|
usage._type == Variables::referenceArray)
|
|
continue;
|
|
|
|
// variable has had memory allocated for it, but hasn't done
|
|
// anything with that memory other than, perhaps, freeing it
|
|
if (usage.unused() && !usage._modified && usage._allocateMemory)
|
|
allocatedButUnusedVariableError(usage._name, varname);
|
|
|
|
// variable has not been written, read, or modified
|
|
else if (usage.unused() && !usage._modified)
|
|
unusedVariableError(usage._name, varname);
|
|
|
|
// variable has not been written but has been modified
|
|
else if (usage._modified && !usage._write && !usage._allocateMemory)
|
|
unassignedVariableError(usage._name, varname);
|
|
|
|
// variable has been written but not read
|
|
else if (!usage._read && !usage._modified)
|
|
unreadVariableError(usage._name, varname);
|
|
|
|
// variable has been read but not written
|
|
else if (!usage._write && !usage._allocateMemory)
|
|
unassignedVariableError(usage._name, varname);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUnusedVar::unusedVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unusedVariable", "Unused variable: " + varname);
|
|
}
|
|
|
|
void CheckUnusedVar::allocatedButUnusedVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unusedAllocatedMemory", "Variable '" + varname + "' is allocated memory that is never used");
|
|
}
|
|
|
|
void CheckUnusedVar::unreadVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is assigned a value that is never used");
|
|
}
|
|
|
|
void CheckUnusedVar::unassignedVariableError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unassignedVariable", "Variable '" + varname + "' is not assigned a value");
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check that all struct members are used
|
|
//---------------------------------------------------------------------------
|
|
void CheckUnusedVar::checkStructMemberUsage()
|
|
{
|
|
if (!_settings->isEnabled("style"))
|
|
return;
|
|
|
|
std::string structname;
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (tok->fileIndex() != 0)
|
|
continue;
|
|
|
|
if (Token::Match(tok, "struct|union %type% {")) {
|
|
structname.clear();
|
|
if (tok->strAt(-1) == "extern")
|
|
continue;
|
|
if ((!tok->previous() || tok->previous()->str() == ";") && Token::Match(tok->linkAt(2), ("} ; " + tok->strAt(1) + " %var% ;").c_str()))
|
|
continue;
|
|
|
|
structname = tok->strAt(1);
|
|
|
|
// Bail out if struct/union contain any functions
|
|
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "(") {
|
|
structname.clear();
|
|
break;
|
|
}
|
|
|
|
if (tok2->str() == "}")
|
|
break;
|
|
}
|
|
|
|
// bail out if struct is inherited
|
|
if (!structname.empty() && Token::findmatch(tok, (",|private|protected|public " + structname).c_str()))
|
|
structname.clear();
|
|
|
|
// Bail out if some data is casted to struct..
|
|
const std::string s("( struct| " + tok->next()->str() + " * ) & %var% [");
|
|
if (Token::findmatch(tok, s.c_str()))
|
|
structname.clear();
|
|
|
|
// Try to prevent false positives when struct members are not used directly.
|
|
if (Token::findmatch(tok, (structname + " *").c_str()))
|
|
structname.clear();
|
|
else if (Token::findmatch(tok, (structname + " %type% *").c_str()))
|
|
structname = "";
|
|
}
|
|
|
|
if (tok->str() == "}")
|
|
structname.clear();
|
|
|
|
if (!structname.empty() && Token::Match(tok, "[{;]")) {
|
|
// Declaring struct variable..
|
|
std::string varname;
|
|
|
|
// declaring a POD variable?
|
|
if (!tok->next()->isStandardType())
|
|
continue;
|
|
|
|
if (Token::Match(tok->next(), "%type% %var% [;[]"))
|
|
varname = tok->strAt(2);
|
|
else if (Token::Match(tok->next(), "%type% %type% %var% [;[]"))
|
|
varname = tok->strAt(3);
|
|
else if (Token::Match(tok->next(), "%type% * %var% [;[]"))
|
|
varname = tok->strAt(3);
|
|
else if (Token::Match(tok->next(), "%type% %type% * %var% [;[]"))
|
|
varname = tok->strAt(4);
|
|
else
|
|
continue;
|
|
|
|
// Check if the struct variable is used anywhere in the file
|
|
const std::string usagePattern(". " + varname);
|
|
bool used = false;
|
|
for (const Token *tok2 = _tokenizer->tokens(); tok2; tok2 = tok2->next()) {
|
|
if (Token::simpleMatch(tok2, usagePattern.c_str())) {
|
|
used = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (! used) {
|
|
unusedStructMemberError(tok->next(), structname, varname);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckUnusedVar::unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::style, "unusedStructMember", "struct or union member '" + structname + "::" + varname + "' is never used");
|
|
}
|