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1746 lines (1509 loc) · 69.6 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2026 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 "astutils.h"
#include "errortypes.h"
#include "fwdanalysis.h"
#include "library.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include "utils.h"
#include "valueflow.h"
#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <list>
#include <set>
#include <utility>
#include <vector>
//---------------------------------------------------------------------------
static const CWE CWE563(563U); // Assignment to Variable without Use ('Unused Variable')
static const CWE CWE665(665U); // Improper Initialization
/** Is scope a raii class scope */
static bool isRaiiClassScope(const Scope *classScope)
{
return classScope && classScope->getDestructor() != nullptr;
}
/** Is ValueType a raii class? */
static bool isRaiiClass(const ValueType *valueType, bool cpp, bool defaultReturn = true)
{
if (!cpp)
return false;
if (!valueType)
return defaultReturn;
if ((valueType->smartPointerType && isRaiiClassScope(valueType->smartPointerType->classScope)) || (!valueType->smartPointerType && valueType->type == ValueType::Type::SMART_POINTER))
return true;
switch (valueType->type) {
case ValueType::Type::UNKNOWN_TYPE:
case ValueType::Type::NONSTD:
return defaultReturn;
case ValueType::Type::RECORD:
if (isRaiiClassScope(valueType->typeScope))
return true;
return defaultReturn;
case ValueType::Type::POD:
case ValueType::Type::SMART_POINTER:
case ValueType::Type::CONTAINER:
case ValueType::Type::ITERATOR:
case ValueType::Type::VOID:
case ValueType::Type::BOOL:
case ValueType::Type::CHAR:
case ValueType::Type::SHORT:
case ValueType::Type::WCHAR_T:
case ValueType::Type::INT:
case ValueType::Type::LONG:
case ValueType::Type::LONGLONG:
case ValueType::Type::UNKNOWN_INT:
case ValueType::Type::FLOAT:
case ValueType::Type::DOUBLE:
case ValueType::Type::LONGDOUBLE:
return false;
}
return defaultReturn;
}
/**
* @brief This class is used create a list of variables within a function.
*/
class Variables {
public:
enum VariableType : std::uint8_t { standard, array, pointer, reference, pointerArray, referenceArray, pointerPointer, none };
/** Store information about variable usage */
class VariableUsage {
public:
explicit VariableUsage(const Variable *var = nullptr,
VariableType type = standard,
bool read = false,
bool write = false,
bool modified = false,
bool allocateMemory = false) :
_var(var),
_lastAccess(var ? var->nameToken() : nullptr),
mType(type),
_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 && !_write);
}
std::set<nonneg int> _aliases;
std::set<const Scope*> _assignments;
const Variable* _var;
const Token* _lastAccess;
VariableType mType;
bool _read;
bool _write;
bool _modified; // read/modify/write
bool _allocateMemory;
};
void clear() {
mVarUsage.clear();
}
void clearConst() {
std::set<int> keys;
for (const std::pair<const nonneg int, Variables::VariableUsage>& var : mVarUsage) {
if (var.second._var && var.second._var->isConst())
keys.emplace(var.first);
}
for (const int key : keys)
mVarUsage.erase(key);
}
const std::map<nonneg int, VariableUsage> &varUsage() const {
return mVarUsage;
}
void addVar(const Variable *var, VariableType type, bool write_);
void allocateMemory(nonneg int varid, const Token* tok);
void read(nonneg int varid, const Token* tok);
void readAliases(nonneg int varid, const Token* tok);
void readAll(nonneg int varid, const Token* tok);
void write(nonneg int varid, const Token* tok);
void writeAliases(nonneg int varid, const Token* tok);
void writeAll(nonneg int varid, const Token* tok);
void use(nonneg int varid, const Token* tok);
void modified(nonneg int varid, const Token* tok);
VariableUsage *find(nonneg int varid);
void alias(nonneg int varid1, nonneg int varid2, bool replace);
void erase(nonneg int varid) {
mVarUsage.erase(varid);
}
void eraseAliases(nonneg int varid);
void eraseAll(nonneg int varid);
void clearAliases(nonneg int varid);
private:
std::map<nonneg int, VariableUsage> mVarUsage;
};
/**
* 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(nonneg int varid1, nonneg int varid2, bool replace)
{
VariableUsage *var1 = find(varid1);
VariableUsage *var2 = find(varid2);
if (!var1 || !var2)
return;
// alias to self
if (varid1 == varid2) {
var1->use();
return;
}
if (replace) {
// remove var1 from all aliases
for (auto i = var1->_aliases.cbegin(); i != var1->_aliases.cend(); ++i) {
VariableUsage *temp = find(*i);
if (temp)
temp->_aliases.erase(var1->_var->declarationId());
}
// remove all aliases from var1
var1->_aliases.clear();
}
// var1 gets all var2s aliases
for (auto i = var2->_aliases.cbegin(); i != var2->_aliases.cend(); ++i) {
if (*i != varid1)
var1->_aliases.insert(*i);
}
// var2 is an alias of var1
var2->_aliases.insert(varid1);
var1->_aliases.insert(varid2);
if (var2->mType == Variables::pointer) {
var2->_read = true;
}
}
void Variables::clearAliases(nonneg int varid)
{
VariableUsage *usage = find(varid);
if (usage) {
// remove usage from all aliases
for (auto i = usage->_aliases.cbegin(); i != usage->_aliases.cend(); ++i) {
VariableUsage *temp = find(*i);
if (temp)
temp->_aliases.erase(usage->_var->declarationId());
}
// remove all aliases from usage
usage->_aliases.clear();
}
}
void Variables::eraseAliases(nonneg int varid)
{
VariableUsage *usage = find(varid);
if (usage) {
for (auto aliases = usage->_aliases.cbegin(); aliases != usage->_aliases.cend(); ++aliases)
erase(*aliases);
}
}
void Variables::eraseAll(nonneg int varid)
{
eraseAliases(varid);
erase(varid);
}
void Variables::addVar(const Variable *var,
VariableType type,
bool write_)
{
if (var->declarationId() > 0) {
mVarUsage.emplace(var->declarationId(), VariableUsage(var, type, false, write_, false));
}
}
void Variables::allocateMemory(nonneg int varid, const Token* tok)
{
VariableUsage *usage = find(varid);
if (usage) {
usage->_allocateMemory = true;
usage->_lastAccess = tok;
}
}
void Variables::read(nonneg int varid, const Token* tok)
{
VariableUsage *usage = find(varid);
if (usage) {
usage->_read = true;
if (tok)
usage->_lastAccess = tok;
}
}
void Variables::readAliases(nonneg int varid, const Token* tok)
{
const VariableUsage *usage = find(varid);
if (usage) {
for (nonneg int const aliases : usage->_aliases) {
VariableUsage *aliased = find(aliases);
if (aliased) {
aliased->_read = true;
aliased->_lastAccess = tok;
}
}
}
}
void Variables::readAll(nonneg int varid, const Token* tok)
{
read(varid, tok);
readAliases(varid, tok);
}
void Variables::write(nonneg int varid, const Token* tok)
{
VariableUsage *usage = find(varid);
if (usage) {
usage->_write = true;
if (!usage->_var->isStatic() && !Token::simpleMatch(tok->next(), "= 0 ;"))
usage->_read = false;
usage->_lastAccess = tok;
}
}
void Variables::writeAliases(nonneg int varid, const Token* tok)
{
VariableUsage *usage = find(varid);
if (usage) {
for (auto aliases = usage->_aliases.cbegin(); aliases != usage->_aliases.cend(); ++aliases) {
VariableUsage *aliased = find(*aliases);
if (aliased) {
aliased->_write = true;
aliased->_lastAccess = tok;
}
}
}
}
void Variables::writeAll(nonneg int varid, const Token* tok)
{
write(varid, tok);
writeAliases(varid, tok);
}
void Variables::use(nonneg int varid, const Token* tok)
{
VariableUsage *usage = find(varid);
if (usage) {
usage->use();
usage->_lastAccess = tok;
for (auto aliases = usage->_aliases.cbegin(); aliases != usage->_aliases.cend(); ++aliases) {
VariableUsage *aliased = find(*aliases);
if (aliased) {
aliased->use();
aliased->_lastAccess = tok;
}
}
}
}
void Variables::modified(nonneg int varid, const Token* tok)
{
VariableUsage *usage = find(varid);
if (usage) {
if (!usage->_var->isStatic())
usage->_read = false;
usage->_modified = true;
usage->_lastAccess = tok;
for (auto aliases = usage->_aliases.cbegin(); aliases != usage->_aliases.cend(); ++aliases) {
VariableUsage *aliased = find(*aliases);
if (aliased) {
aliased->_modified = true;
aliased->_lastAccess = tok;
}
}
}
}
Variables::VariableUsage *Variables::find(nonneg int varid)
{
if (varid) {
const auto i = mVarUsage.find(varid);
if (i != mVarUsage.end())
return &i->second;
}
return nullptr;
}
static const Token* doAssignment(Variables &variables, const Token *tok, bool dereference, const Scope *scope)
{
// a = a + b;
if (Token::Match(tok, "%var% = %var% !!;")) {
const Token* rhsVarTok = tok->tokAt(2);
if (tok->varId() == rhsVarTok->varId()) {
return rhsVarTok;
}
}
if (Token::Match(tok, "%var% %assign%") && tok->strAt(1) != "=")
return tok->next();
const Token* const tokOld = tok;
// check for aliased variable
const nonneg int varid1 = tok->varId();
Variables::VariableUsage *var1 = variables.find(varid1);
if (var1) {
if (var1->mType == Variables::pointerArray)
variables.use(varid1, tok);
// jump behind '='
tok = tok->next();
while (!tok->isAssignmentOp()) {
if (tok->varId())
variables.read(tok->varId(), tok);
tok = tok->next();
}
tok = tok->next();
if (Token::Match(tok, "( const| struct|union| %type% * ) ( ("))
tok = tok->link()->next();
if (Token::Match(tok, "( [(<] const| struct|union| %type% *| [>)]"))
tok = tok->next();
if (Token::Match(tok, "(| &| %name%") ||
(Token::Match(tok->next(), "< const| struct|union| %type% *| > ( &| %name%"))) {
bool addressOf = false;
if (Token::Match(tok, "%var% ."))
variables.use(tok->varId(), tok); // 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();
while ((tok->isName() && tok->varId() == 0) || (tok->str() == "*") || (tok->str() == ")"))
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();
}
} else if (Token::Match(tok, "%cop% %var%")) {
variables.read(tok->next()->varId(), tok);
}
}
// 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)
return tokOld;
if (tok->str() == "*")
tok = tok->next();
tok = tok->tokAt(2);
if (!tok)
return tokOld;
if (tok->str() == "&") {
addressOf = true;
tok = tok->next();
}
}
// no cast, no ?
else if (!Token::Match(tok, "%name% ?")) {
if (tok->str() == "&") {
addressOf = true;
tok = tok->next();
} else if (tok->str() == "new")
return tokOld;
}
// check if variable is local
const nonneg int varid2 = tok->varId();
const Variables::VariableUsage* var2 = variables.find(varid2);
if (var2) { // local variable (alias or read it)
if (var1->mType == Variables::pointer || var1->mType == Variables::pointerArray) {
if (dereference)
variables.read(varid2, tok);
else {
if (addressOf ||
var2->mType == Variables::array ||
var2->mType == Variables::pointer) {
bool replace = true;
// pointerArray => don't replace
if (var1->mType == Variables::pointerArray)
replace = false;
// check if variable declared in same scope
else if (scope == var1->_var->scope())
replace = true;
// not in same scope as declaration
else {
// no other assignment in this scope
if (var1->_assignments.find(scope) == var1->_assignments.end() ||
scope->type == ScopeType::eSwitch) {
// nothing to replace
// cppcheck-suppress duplicateBranch - remove when TODO below is address
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->mType == Variables::reference)
variables.readAliases(varid2, tok);
else
variables.read(varid2, tok);
} else {
variables.readAll(varid2, tok);
}
}
} else if (var1->mType == Variables::reference || var1->mType == Variables::referenceArray) {
variables.alias(varid1, varid2, true);
} else if (var1->mType == Variables::standard && addressOf) {
variables.alias(varid1, varid2, true);
} else {
if (var2->mType == Variables::pointer || var2->mType == Variables::pointerArray) {
variables.alias(varid1, varid2, true);
variables.readAliases(varid2, tok);
}
variables.read(varid2, tok);
}
} else { // not a local variable (or an unsupported local variable)
if (var1->mType == Variables::pointer && !dereference) {
// check if variable declaration is in this scope
if (var1->_var->scope() == scope) {
// If variable is used in RHS then "use" variable
for (const Token *rhs = tok; rhs && rhs->str() != ";"; rhs = rhs->next()) {
if (rhs->varId() == varid1) {
variables.use(varid1, tok);
break;
}
}
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), "%name% .")) {
const Token *rhsVarTok = tok->tokAt(2);
if (rhsVarTok && rhsVarTok->varId()) {
const nonneg int varid2 = rhsVarTok->varId();
const Variables::VariableUsage *var2 = variables.find(varid2);
// struct member aliased to local variable
if (var2 && (var2->mType == Variables::array ||
var2->mType == Variables::pointer)) {
// erase aliased variable and all variables that alias it
// to prevent false positives
variables.eraseAll(varid2);
}
}
}
// Possible pointer alias
else if (Token::Match(tok, "%name% = %name% ;")) {
const nonneg int varid2 = tok->tokAt(2)->varId();
const Variables::VariableUsage *var2 = variables.find(varid2);
if (var2 && (var2->mType == Variables::array ||
var2->mType == Variables::pointer)) {
variables.use(varid2,tok);
}
}
return tok;
}
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;
}
static bool isVarDecl(const Token *tok)
{
return tok && tok->variable() && tok->variable()->nameToken() == tok;
}
// 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, ". %name%"))
tok = tok->tokAt(2);
else
break;
}
return tok;
}
static void useFunctionArgs(const Token *tok, Variables& variables)
{
// TODO: Match function args to see if they are const or not. Assume that const data is not written.
if (!tok)
return;
if (tok->str() == ",") {
useFunctionArgs(tok->astOperand1(), variables);
useFunctionArgs(tok->astOperand2(), variables);
} else if (Token::Match(tok, "[+:]") && (!tok->valueType() || tok->valueType()->pointer)) {
useFunctionArgs(tok->astOperand1(), variables);
useFunctionArgs(tok->astOperand2(), variables);
} else if (tok->variable() && tok->variable()->isArray()) {
variables.use(tok->varId(), tok);
}
}
//---------------------------------------------------------------------------
// Usage of function variables
//---------------------------------------------------------------------------
void CheckUnusedVarImpl::checkFunctionVariableUsage_iterateScopes(const Scope* const scope, Variables& variables) const
{
// Find declarations if the scope is executable..
if (scope->isExecutable()) {
// Find declarations
for (auto i = scope->varlist.cbegin(); i != scope->varlist.cend(); ++i) {
if (i->isThrow() || i->isExtern())
continue;
Variables::VariableType type = Variables::none;
if (i->isArray() && (i->nameToken()->strAt(-1) == "*" || i->nameToken()->strAt(-2) == "*"))
type = Variables::pointerArray;
else if (i->isArray() && i->nameToken()->strAt(-1) == "&")
type = Variables::referenceArray;
else if (i->isArray())
type = Variables::array;
else if (i->isReference() && !(i->valueType() && i->valueType()->type == ValueType::UNKNOWN_TYPE && Token::simpleMatch(i->typeStartToken(), "auto")))
type = Variables::reference;
else if (i->nameToken()->strAt(-1) == "*" && i->nameToken()->strAt(-2) == "*")
type = Variables::pointerPointer;
else if (i->isPointerToArray())
type = Variables::pointerPointer;
else if (i->isPointer())
type = Variables::pointer;
else if (mTokenizer->isC() ||
i->typeEndToken()->isStandardType() ||
i->isStlType() ||
mTokenizer->getSymbolDatabase()->isRecordTypeWithoutSideEffects(i->type()) ||
mSettings.library.detectContainer(i->typeStartToken()) ||
mSettings.library.getTypeCheck("unusedvar", i->typeStartToken()->str()) == Library::TypeCheck::check)
type = Variables::standard;
if (type == Variables::none || isPartOfClassStructUnion(i->typeStartToken()))
continue;
const Token* defValTok = i->nameToken()->next();
if (Token::Match(i->nameToken()->previous(), "& %var% )"))
defValTok = defValTok->next();
while (defValTok && defValTok->str() == "[")
defValTok = defValTok->link()->next();
if (Token::simpleMatch(defValTok, ") ("))
defValTok = defValTok->linkAt(1)->next();
for (; defValTok; defValTok = defValTok->next()) {
if (defValTok->str() == "[")
defValTok = defValTok->link();
else if (defValTok->str() == "(" || defValTok->str() == "{" || defValTok->str() == "=" || defValTok->str() == ":") {
variables.addVar(&*i, type, true);
break;
} else if (defValTok->str() == ";" || defValTok->str() == "," || defValTok->str() == ")") {
variables.addVar(&*i, type, i->isStatic() && i->scope()->type != ScopeType::eFunction);
break;
}
}
if (i->isArray() && i->isClass() && // Array of class/struct members. Initialized by ctor except for std::array
!(i->isStlType() && i->valueType() && i->valueType()->containerTypeToken && i->valueType()->containerTypeToken->isStandardType()))
variables.write(i->declarationId(), i->nameToken());
if (i->isArray() && Token::Match(i->nameToken(), "%name% [ %var% ]")) // Array index variable read.
variables.read(i->nameToken()->tokAt(2)->varId(), i->nameToken());
if (defValTok && defValTok->next()) {
// simple assignment "var = 123"
if (defValTok->str() == "=" && defValTok->strAt(1) != "{") {
doAssignment(variables, i->nameToken(), false, scope);
} else {
// could be "var = {...}" OR "var{...}" (since C++11)
const Token* tokBraceStart = nullptr;
if (Token::simpleMatch(defValTok, "= {")) {
// "var = {...}"
tokBraceStart = defValTok->next();
} else if (defValTok->str() == "{") {
// "var{...}"
tokBraceStart = defValTok;
}
if (tokBraceStart) {
for (const Token* tok = tokBraceStart->next(); tok && tok != tokBraceStart->link(); tok = tok->next()) {
if (tok->varId()) {
// Variables used to initialize the array read.
variables.read(tok->varId(), i->nameToken());
}
}
}
}
}
}
}
// Check variable usage
const Token *tok;
if (scope->type == ScopeType::eFunction)
tok = scope->bodyStart->next();
else
tok = scope->classDef->next();
for (; tok && tok != scope->bodyEnd; tok = tok->next()) {
if (tok->str() == "{" && tok != scope->bodyStart && !tok->previous()->varId()) {
if (std::any_of(scope->nestedList.cbegin(), scope->nestedList.cend(), [&](const Scope* s) {
return s->bodyStart == tok;
})) {
checkFunctionVariableUsage_iterateScopes(tok->scope(), variables); // Scan child scope
tok = tok->link();
}
if (!tok)
break;
}
if (Token::Match(tok, "asm ( %str% )")) {
variables.clear();
break;
}
// templates
if (tok->isName() && endsWith(tok->str(), '>')) {
// TODO: This is a quick fix to handle when constants are used
// as template parameters.
variables.clearConst();
}
else if (Token::Match(tok->previous(), "[;{}]")) {
for (const Token* tok2 = tok->next(); tok2; tok2 = tok2->next()) {
if (tok2->varId()) {
// Is this a variable declaration?
const Variable *var = tok2->variable();
if (!var || var->nameToken() != tok2)
continue;
// Mark template parameters used in declaration as use..
if (tok2->strAt(-1) == ">") {
for (const Token *tok3 = tok; tok3 != tok2; tok3 = tok3->next()) {
if (tok3->varId())
variables.use(tok3->varId(), tok3);
}
}
// Skip variable declaration..
tok = tok2->next();
if (Token::Match(tok, "( %name% )")) // Simple initialization through copy ctor
tok = tok->next();
else if (Token::Match(tok, "= %var% ;")) { // Simple initialization
tok = tok->next();
if (!var->isReference())
variables.read(tok->varId(), tok);
} else if (tok->str() == "[" && Token::simpleMatch(skipBrackets(tok),"= {")) {
const Token * const rhs1 = skipBrackets(tok)->next();
for (const Token *rhs = rhs1->link(); rhs != rhs1; rhs = rhs->previous()) {
if (rhs->varId())
variables.readAll(rhs->varId(), rhs);
}
} else if (var->typeEndToken()->str() == ">") // Be careful with types like std::vector
tok = tok->previous();
break;
}
if (Token::Match(tok2, "[;({=]"))
break;
}
}
// Freeing memory (not considered "using" the pointer if it was also allocated in this function)
if ((Token::Match(tok, "%name% ( %var% )") && mSettings.library.getDeallocFuncInfo(tok)) ||
(tok->isCpp() && (Token::Match(tok, "delete %var% ;") || Token::Match(tok, "delete [ ] %var% ;")))) {
nonneg int varid = 0;
if (tok->str() != "delete") {
const Token *varTok = tok->tokAt(2);
varid = varTok->varId();
tok = varTok->next();
} else if (tok->strAt(1) == "[") {
const Token *varTok = tok->tokAt(3);
varid = varTok->varId();
tok = varTok;
} else {
varid = tok->next()->varId();
tok = tok->next();
}
const Variables::VariableUsage *const var = variables.find(varid);
if (var) {
if (!var->_aliases.empty())
variables.use(varid, tok);
else if (!var->_allocateMemory)
variables.readAll(varid, tok);
}
}
else if (Token::Match(tok, "return|throw")) {
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
if (tok2->varId())
variables.readAll(tok2->varId(), tok);
else if (tok2->str() == ";")
break;
}
}
// assignment
else if (Token::Match(tok, "*| ++|--| %name% ++|--| %assign%") ||
Token::Match(tok, "*| ( const| %type% *| ) %name% %assign%")) {
bool dereference = false;
bool pre = false;
bool post = false;
if (tok->str() == "*") {
dereference = true;
tok = tok->next();
}
if (Token::Match(tok, "( const| %type% *| ) %name% %assign%"))
tok = tok->link()->next();
else if (tok->str() == "(")
tok = tok->next();
if (tok->tokType() == Token::eIncDecOp) {
pre = true;
tok = tok->next();
}
if (tok->next()->tokType() == Token::eIncDecOp)
post = true;
const nonneg int varid1 = tok->varId();
const Token * const start = tok;
// assignment in while head..
bool inwhile = false;
{
const Token *parent = tok->astParent();
while (parent) {
if (Token::simpleMatch(parent->previous(), "while (")) {
inwhile = true;
break;
}
parent = parent->astParent();
}
}
tok = doAssignment(variables, tok, dereference, scope);
if (tok && tok->isAssignmentOp() && tok->str() != "=") {
variables.use(varid1, tok);
if (Token::Match(tok, "%assign% %name%")) {
tok = tok->next();
variables.read(tok->varId(), tok);
}
}
if (pre || post)
variables.use(varid1, tok);
if (dereference) {
const Variables::VariableUsage *const var = variables.find(varid1);
if (var && var->mType == Variables::array)
variables.write(varid1, tok);
variables.writeAliases(varid1, tok);
variables.read(varid1, tok);
} else {
const Variables::VariableUsage *const var = variables.find(varid1);
if (var && (inwhile || start->strAt(-1) == ",")) {
variables.use(varid1, tok);
} else if (var && var->mType == Variables::reference) {
variables.writeAliases(varid1, tok);
variables.read(varid1, tok);
}
// Consider allocating memory separately because allocating/freeing alone does not constitute using the variable
else if (var && var->mType == Variables::pointer &&
Token::Match(start, "%name% =") &&
findAllocFuncCallToken(start->next()->astOperand2(), mSettings.library)) {
const Token *allocFuncCallToken = findAllocFuncCallToken(start->next()->astOperand2(), mSettings.library);
const Library::AllocFunc *allocFunc = mSettings.library.getAllocFuncInfo(allocFuncCallToken);
bool allocateMemory = !allocFunc || Library::ismemory(allocFunc->groupId);
if (allocFuncCallToken->str() == "new") {
const Token *type = allocFuncCallToken->next();
// skip nothrow
if (type->isCpp() && (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 = start->variable();
if (!variable || !mTokenizer->getSymbolDatabase()->isRecordTypeWithoutSideEffects(variable->type()))
allocateMemory = false;
}
}
if (allocateMemory)
variables.allocateMemory(varid1, tok);
else
variables.write(varid1, tok);
} else if (varid1 && Token::Match(tok, "%varid% .", varid1)) {
variables.read(varid1, tok);
variables.write(varid1, start);
} else {
variables.write(varid1, tok);
}
}
const Variables::VariableUsage * const var2 = variables.find(tok->varId());
if (var2) {
if (var2->mType == Variables::reference) {
variables.writeAliases(tok->varId(), tok);
variables.read(tok->varId(), tok);