/*
* 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 "astutils.h"
#include "config.h"
#include "errortypes.h"
#include "infer.h"
#include "library.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "utils.h"
#include "valueflow.h"
#include "valueptr.h"
#include "checkclass.h"
#include <algorithm>
#include <functional>
#include <initializer_list>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <type_traits>
#include <unordered_map>
#include <utility>
const Token* findAstNode(const Token* ast, const std::function<bool(const Token*)>& pred)
{
const Token* result = nullptr;
visitAstNodes(ast, [&](const Token* tok) {
if (pred(tok)) {
result = tok;
return ChildrenToVisit::done;
}
return ChildrenToVisit::op1_and_op2;
});
return result;
}
const Token* findExpression(const nonneg int exprid,
const Token* start,
const Token* end,
const std::function<bool(const Token*)>& pred)
{
if (!precedes(start, end))
return nullptr;
if (exprid == 0)
return nullptr;
for (const Token* tok = start; tok != end; tok = tok->next()) {
if (tok->exprId() != exprid)
continue;
if (pred(tok))
return tok;
}
return nullptr;
}
static int findArgumentPosRecursive(const Token* tok, const Token* tokToFind, bool &found, nonneg int depth=0)
{
++depth;
if (!tok || depth >= 100)
return -1;
if (tok->str() == ",") {
int res = findArgumentPosRecursive(tok->astOperand1(), tokToFind, found, depth);
if (res == -1)
return -1;
if (found)
return res;
int argn = res;
res = findArgumentPosRecursive(tok->astOperand2(), tokToFind, found, depth);
if (res == -1)
return -1;
return argn + res;
} else {
if (tokToFind == tok)
found = true;
return 1;
}
}
static int findArgumentPos(const Token* tok, const Token* tokToFind){
bool found = false;
int argn = findArgumentPosRecursive(tok, tokToFind, found, 0);
if (found)
return argn - 1;
return -1;
}
static int getArgumentPos(const Token* ftok, const Token* tokToFind){
const Token* tok = ftok;
if (Token::Match(tok, "%name% (|{"))
tok = ftok->next();
if (!Token::Match(tok, "(|{|["))
return -1;
const Token* startTok = tok->astOperand2();
if (!startTok && tok->next() != tok->link())
startTok = tok->astOperand1();
return findArgumentPos(startTok, tokToFind);
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static void astFlattenRecursive(T* tok, std::vector<T*>* result, const char* op, nonneg int depth = 0)
{
++depth;
if (!tok || depth >= 100)
return;
if (tok->str() == op) {
astFlattenRecursive(tok->astOperand1(), result, op, depth);
astFlattenRecursive(tok->astOperand2(), result, op, depth);
} else {
result->push_back(tok);
}
}
std::vector<const Token*> astFlatten(const Token* tok, const char* op)
{
std::vector<const Token*> result;
astFlattenRecursive(tok, &result, op);
return result;
}
std::vector<Token*> astFlatten(Token* tok, const char* op)
{
std::vector<Token*> result;
astFlattenRecursive(tok, &result, op);
return result;
}
bool astHasToken(const Token* root, const Token * tok)
{
if (!root)
return false;
while (tok->astParent() && tok != root)
tok = tok->astParent();
return root == tok;
}
bool astHasVar(const Token * tok, nonneg int varid)
{
if (!tok)
return false;
if (tok->varId() == varid)
return true;
return astHasVar(tok->astOperand1(), varid) || astHasVar(tok->astOperand2(), varid);
}
static bool astIsCharWithSign(const Token *tok, ValueType::Sign sign)
{
if (!tok)
return false;
const ValueType *valueType = tok->valueType();
if (!valueType)
return false;
return valueType->type == ValueType::Type::CHAR && valueType->pointer == 0U && valueType->sign == sign;
}
bool astIsSignedChar(const Token *tok)
{
return astIsCharWithSign(tok, ValueType::Sign::SIGNED);
}
bool astIsUnknownSignChar(const Token *tok)
{
return astIsCharWithSign(tok, ValueType::Sign::UNKNOWN_SIGN);
}
bool astIsGenericChar(const Token* tok)
{
return !astIsPointer(tok) && tok && tok->valueType() && (tok->valueType()->type == ValueType::Type::CHAR || tok->valueType()->type == ValueType::Type::WCHAR_T);
}
bool astIsPrimitive(const Token* tok)
{
const ValueType* vt = tok ? tok->valueType() : nullptr;
if (!vt)
return false;
return vt->isPrimitive();
}
bool astIsIntegral(const Token *tok, bool unknown)
{
const ValueType *vt = tok ? tok->valueType() : nullptr;
if (!vt)
return unknown;
return vt->isIntegral() && vt->pointer == 0U;
}
bool astIsUnsigned(const Token* tok)
{
return tok && tok->valueType() && tok->valueType()->sign == ValueType::UNSIGNED;
}
bool astIsFloat(const Token *tok, bool unknown)
{
const ValueType *vt = tok ? tok->valueType() : nullptr;
if (!vt)
return unknown;
return vt->type >= ValueType::Type::FLOAT && vt->pointer == 0U;
}
bool astIsBool(const Token *tok)
{
return tok && (tok->isBoolean() || (tok->valueType() && tok->valueType()->type == ValueType::Type::BOOL && !tok->valueType()->pointer));
}
bool astIsPointer(const Token *tok)
{
return tok && tok->valueType() && tok->valueType()->pointer;
}
bool astIsSmartPointer(const Token* tok)
{
return tok && tok->valueType() && tok->valueType()->smartPointerTypeToken;
}
bool astIsUniqueSmartPointer(const Token* tok)
{
if (!astIsSmartPointer(tok))
return false;
if (!tok->valueType()->smartPointer)
return false;
return tok->valueType()->smartPointer->unique;
}
bool astIsIterator(const Token *tok)
{
return tok && tok->valueType() && tok->valueType()->type == ValueType::Type::ITERATOR;
}
bool astIsContainer(const Token* tok) {
return getLibraryContainer(tok) != nullptr && !astIsIterator(tok);
}
bool astIsContainerView(const Token* tok)
{
const Library::Container* container = getLibraryContainer(tok);
return container && !astIsIterator(tok) && container->view;
}
bool astIsContainerOwned(const Token* tok) {
return astIsContainer(tok) && !astIsContainerView(tok);
}
std::string astCanonicalType(const Token *expr)
{
if (!expr)
return "";
std::pair<const Token*, const Token*> decl = Token::typeDecl(expr);
if (decl.first && decl.second) {
std::string ret;
for (const Token *type = decl.first; Token::Match(type,"%name%|::") && type != decl.second; type = type->next()) {
if (!Token::Match(type, "const|static"))
ret += type->str();
}
return ret;
}
return "";
}
static bool match(const Token *tok, const std::string &rhs)
{
if (tok->str() == rhs)
return true;
if (!tok->varId() && tok->hasKnownIntValue() && MathLib::toString(tok->values().front().intvalue) == rhs)
return true;
return false;
}
const Token * astIsVariableComparison(const Token *tok, const std::string &comp, const std::string &rhs, const Token **vartok)
{
if (!tok)
return nullptr;
const Token *ret = nullptr;
if (tok->isComparisonOp()) {
if (tok->astOperand1() && match(tok->astOperand1(), rhs)) {
// Invert comparator
std::string s = tok->str();
if (s[0] == '>')
s[0] = '<';
else if (s[0] == '<')
s[0] = '>';
if (s == comp) {
ret = tok->astOperand2();
}
} else if (tok->str() == comp && tok->astOperand2() && match(tok->astOperand2(), rhs)) {
ret = tok->astOperand1();
}
} else if (comp == "!=" && rhs == std::string("0")) {
if (tok->str() == "!") {
ret = tok->astOperand1();
// handle (!(x==0)) as (x!=0)
astIsVariableComparison(ret, "==", "0", &ret);
} else
ret = tok;
} else if (comp == "==" && rhs == std::string("0")) {
if (tok->str() == "!") {
ret = tok->astOperand1();
// handle (!(x!=0)) as (x==0)
astIsVariableComparison(ret, "!=", "0", &ret);
}
}
while (ret && ret->str() == ".")
ret = ret->astOperand2();
if (ret && ret->str() == "=" && ret->astOperand1() && ret->astOperand1()->varId())
ret = ret->astOperand1();
else if (ret && ret->varId() == 0U)
ret = nullptr;
if (vartok)
*vartok = ret;
return ret;
}
bool isVariableDecl(const Token* tok)
{
if (!tok)
return false;
const Variable* var = tok->variable();
if (!var)
return false;
if (var->nameToken() == tok)
return true;
if (Token::Match(var->declEndToken(), "; %var%") && var->declEndToken()->next() == tok)
return true;
return false;
}
bool isTemporary(bool cpp, const Token* tok, const Library* library, bool unknown)
{
if (!tok)
return false;
if (Token::simpleMatch(tok, "."))
return (tok->originalName() != "->" && isTemporary(cpp, tok->astOperand1(), library)) ||
isTemporary(cpp, tok->astOperand2(), library);
if (Token::Match(tok, ",|::"))
return isTemporary(cpp, tok->astOperand2(), library);
if (tok->isCast() || (cpp && isCPPCast(tok)))
return isTemporary(cpp, tok->astOperand2(), library);
if (Token::Match(tok, "?|.|[|++|--|%name%|%assign%"))
return false;
if (tok->isUnaryOp("*"))
return false;
if (Token::Match(tok, "&|<<|>>") && isLikelyStream(cpp, tok->astOperand1()))
return false;
if (Token::simpleMatch(tok, "(") && tok->astOperand1() &&
(tok->astOperand2() || Token::simpleMatch(tok->next(), ")"))) {
if (tok->valueType()) {
return tok->valueType()->reference == Reference::None;
}
const Token* ftok = nullptr;
if (Token::simpleMatch(tok->previous(), ">") && tok->previous()->link())
ftok = tok->previous()->link()->previous();
else
ftok = tok->previous();
if (!ftok)
return false;
if (const Function * f = ftok->function()) {
return !Function::returnsReference(f, true);
} else if (ftok->type()) {
return true;
} else if (library) {
std::string returnType = library->returnValueType(ftok);
return !returnType.empty() && returnType.back() != '&';
} else {
return unknown;
}
}
if (tok->isCast())
return false;
// Currying a function is unknown in cppcheck
if (Token::simpleMatch(tok, "(") && Token::simpleMatch(tok->astOperand1(), "("))
return unknown;
if (Token::simpleMatch(tok, "{") && Token::simpleMatch(tok->astParent(), "return") && tok->astOperand1() &&
!tok->astOperand2())
return isTemporary(cpp, tok->astOperand1(), library);
return true;
}
static bool isFunctionCall(const Token* tok)
{
if (Token::Match(tok, "%name% ("))
return true;
if (Token::Match(tok, "%name% <") && Token::simpleMatch(tok->next()->link(), "> ("))
return true;
if (Token::Match(tok, "%name% ::"))
return isFunctionCall(tok->tokAt(2));
return false;
}
static bool hasToken(const Token * startTok, const Token * stopTok, const Token * tok)
{
for (const Token * tok2 = startTok; tok2 != stopTok; tok2 = tok2->next()) {
if (tok2 == tok)
return true;
}
return false;
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static T* previousBeforeAstLeftmostLeafGeneric(T* tok)
{
if (!tok)
return nullptr;
T* leftmostLeaf = tok;
while (leftmostLeaf->astOperand1())
leftmostLeaf = leftmostLeaf->astOperand1();
return leftmostLeaf->previous();
}
const Token* previousBeforeAstLeftmostLeaf(const Token* tok)
{
return previousBeforeAstLeftmostLeafGeneric(tok);
}
Token* previousBeforeAstLeftmostLeaf(Token* tok)
{
return previousBeforeAstLeftmostLeafGeneric(tok);
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static T* nextAfterAstRightmostLeafGeneric(T* tok)
{
const Token * rightmostLeaf = tok;
if (!rightmostLeaf || !rightmostLeaf->astOperand1())
return nullptr;
do {
if (const Token* lam = findLambdaEndToken(rightmostLeaf)) {
rightmostLeaf = lam;
break;
}
if (rightmostLeaf->astOperand2() && precedes(rightmostLeaf, rightmostLeaf->astOperand2()))
rightmostLeaf = rightmostLeaf->astOperand2();
else if (rightmostLeaf->astOperand1() && precedes(rightmostLeaf, rightmostLeaf->astOperand1()))
rightmostLeaf = rightmostLeaf->astOperand1();
else
break;
} while (rightmostLeaf->astOperand1() || rightmostLeaf->astOperand2());
while (Token::Match(rightmostLeaf->next(), "]|)") && !hasToken(rightmostLeaf->next()->link(), rightmostLeaf->next(), tok))
rightmostLeaf = rightmostLeaf->next();
if (Token::Match(rightmostLeaf, "{|(|[") && rightmostLeaf->link())
rightmostLeaf = rightmostLeaf->link();
return rightmostLeaf->next();
}
const Token* nextAfterAstRightmostLeaf(const Token* tok)
{
return nextAfterAstRightmostLeafGeneric(tok);
}
Token* nextAfterAstRightmostLeaf(Token* tok)
{
return nextAfterAstRightmostLeafGeneric(tok);
}
const Token* astParentSkipParens(const Token* tok)
{
return astParentSkipParens(const_cast<Token*>(tok));
}
Token* astParentSkipParens(Token* tok)
{
if (!tok)
return nullptr;
Token * parent = tok->astParent();
if (!Token::simpleMatch(parent, "("))
return parent;
if (parent->link() != nextAfterAstRightmostLeaf(tok))
return parent;
if (Token::Match(parent->previous(), "%name% (") ||
(Token::simpleMatch(parent->previous(), "> (") && parent->previous()->link()))
return parent;
return astParentSkipParens(parent);
}
const Token* getParentMember(const Token * tok)
{
if (!tok)
return tok;
const Token * parent = tok->astParent();
if (!Token::simpleMatch(parent, "."))
return tok;
if (astIsRHS(tok)) {
if (Token::simpleMatch(parent->astOperand1(), "."))
return parent->astOperand1()->astOperand2();
return parent->astOperand1();
}
const Token * gparent = parent->astParent();
if (!Token::simpleMatch(gparent, ".") || gparent->astOperand2() != parent)
return tok;
if (gparent->astOperand1())
return gparent->astOperand1();
return tok;
}
const Token* getParentLifetime(const Token* tok)
{
if (!tok)
return tok;
// Skipping checking for variable if its a pointer-to-member
if (!Token::simpleMatch(tok->previous(), ". *")) {
const Variable* var = tok->variable();
// TODO: Call getLifetimeVariable for deeper analysis
if (!var)
return tok;
if (var->isLocal() || var->isArgument())
return tok;
}
const Token* parent = getParentMember(tok);
if (parent != tok)
return getParentLifetime(parent);
return tok;
}
static std::vector<const Token*> getParentMembers(const Token* tok)
{
if (!tok)
return {};
if (!Token::simpleMatch(tok->astParent(), "."))
return {tok};
const Token* parent = tok;
while (Token::simpleMatch(parent->astParent(), "."))
parent = parent->astParent();
std::vector<const Token*> result;
for (const Token* tok2 : astFlatten(parent, ".")) {
if (Token::simpleMatch(tok2, "(") && Token::simpleMatch(tok2->astOperand1(), ".")) {
std::vector<const Token*> sub = getParentMembers(tok2->astOperand1());
result.insert(result.end(), sub.begin(), sub.end());
}
result.push_back(tok2);
}
return result;
}
const Token* getParentLifetime(bool cpp, const Token* tok, const Library* library)
{
std::vector<const Token*> members = getParentMembers(tok);
if (members.size() < 2)
return tok;
// Find the first local variable or temporary
auto it = std::find_if(members.rbegin(), members.rend(), [&](const Token* tok2) {
const Variable* var = tok2->variable();
if (var) {
return var->isLocal() || var->isArgument();
} else {
return isTemporary(cpp, tok2, library);
}
});
if (it == members.rend())
return tok;
// If any of the submembers are borrowed types then stop
if (std::any_of(it.base() - 1, members.end() - 1, [&](const Token* tok2) {
if (astIsPointer(tok2) || astIsContainerView(tok2) || astIsIterator(tok2))
return true;
if (!astIsUniqueSmartPointer(tok2)) {
if (astIsSmartPointer(tok2))
return true;
const Token* dotTok = tok2->next();
if (!Token::simpleMatch(dotTok, ".")) {
const Token* endTok = nextAfterAstRightmostLeaf(tok2);
if (!endTok)
dotTok = tok2->next();
else if (Token::simpleMatch(endTok, "."))
dotTok = endTok;
else if (Token::simpleMatch(endTok->next(), "."))
dotTok = endTok->next();
}
// If we are dereferencing the member variable then treat it as borrowed
if (Token::simpleMatch(dotTok, ".") && dotTok->originalName() == "->")
return true;
}
const Variable* var = tok2->variable();
return var && var->isReference();
}))
return nullptr;
return *it;
}
bool astIsLHS(const Token* tok)
{
if (!tok)
return false;
const Token* parent = tok->astParent();
if (!parent)
return false;
if (!parent->astOperand1())
return false;
if (!parent->astOperand2())
return false;
return parent->astOperand1() == tok;
}
bool astIsRHS(const Token* tok)
{
if (!tok)
return false;
const Token* parent = tok->astParent();
if (!parent)
return false;
if (!parent->astOperand1())
return false;
if (!parent->astOperand2())
return false;
return parent->astOperand2() == tok;
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static T* getCondTokImpl(T* tok)
{
if (!tok)
return nullptr;
if (Token::simpleMatch(tok, "("))
return getCondTok(tok->previous());
if (Token::simpleMatch(tok, "for") && Token::simpleMatch(tok->next()->astOperand2(), ";") &&
tok->next()->astOperand2()->astOperand2())
return tok->next()->astOperand2()->astOperand2()->astOperand1();
if (Token::simpleMatch(tok->next()->astOperand2(), ";"))
return tok->next()->astOperand2()->astOperand1();
return tok->next()->astOperand2();
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static T* getCondTokFromEndImpl(T* endBlock)
{
if (!Token::simpleMatch(endBlock, "}"))
return nullptr;
T* startBlock = endBlock->link();
if (!Token::simpleMatch(startBlock, "{"))
return nullptr;
if (Token::simpleMatch(startBlock->previous(), ")")) {
return getCondTok(startBlock->previous()->link());
} else if (Token::simpleMatch(startBlock->tokAt(-2), "} else {")) {
return getCondTokFromEnd(startBlock->tokAt(-2));
}
return nullptr;
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static T* getInitTokImpl(T* tok)
{
if (!tok)
return nullptr;
if (Token::Match(tok, "%name% ("))
return getInitTokImpl(tok->next());
if (tok->str() != "(")
return nullptr;
if (!Token::simpleMatch(tok->astOperand2(), ";"))
return nullptr;
if (Token::simpleMatch(tok->astOperand2()->astOperand1(), ";"))
return nullptr;
return tok->astOperand2()->astOperand1();
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
static T* getStepTokImpl(T* tok)
{
if (!tok)
return nullptr;
if (Token::Match(tok, "%name% ("))
return getStepTokImpl(tok->next());
if (tok->str() != "(")
return nullptr;
if (!Token::simpleMatch(tok->astOperand2(), ";"))
return nullptr;
if (!Token::simpleMatch(tok->astOperand2()->astOperand2(), ";"))
return nullptr;
return tok->astOperand2()->astOperand2()->astOperand2();
}
Token* getCondTok(Token* tok)
{
return getCondTokImpl(tok);
}
const Token* getCondTok(const Token* tok)
{
return getCondTokImpl(tok);
}
Token* getCondTokFromEnd(Token* endBlock)
{
return getCondTokFromEndImpl(endBlock);
}
const Token* getCondTokFromEnd(const Token* endBlock)
{
return getCondTokFromEndImpl(endBlock);
}
Token* getInitTok(Token* tok) {
return getInitTokImpl(tok);
}
const Token* getInitTok(const Token* tok) {
return getInitTokImpl(tok);
}
Token* getStepTok(Token* tok) {
return getStepTokImpl(tok);
}
const Token* getStepTok(const Token* tok) {
return getStepTokImpl(tok);
}
const Token *findNextTokenFromBreak(const Token *breakToken)
{
const Scope *scope = breakToken->scope();
while (scope) {
if (scope->isLoopScope() || scope->type == Scope::ScopeType::eSwitch) {
if (scope->type == Scope::ScopeType::eDo && Token::simpleMatch(scope->bodyEnd, "} while ("))
return scope->bodyEnd->linkAt(2)->next();
return scope->bodyEnd;
}
scope = scope->nestedIn;
}
return nullptr;
}
bool extractForLoopValues(const Token *forToken,
nonneg int * const varid,
bool * const knownInitValue,
MathLib::bigint * const initValue,
bool * const partialCond,
MathLib::bigint * const stepValue,
MathLib::bigint * const lastValue)
{
if (!Token::simpleMatch(forToken, "for (") || !Token::simpleMatch(forToken->next()->astOperand2(), ";"))
return false;
const Token *initExpr = forToken->next()->astOperand2()->astOperand1();
const Token *condExpr = forToken->next()->astOperand2()->astOperand2()->astOperand1();
const Token *incExpr = forToken->next()->astOperand2()->astOperand2()->astOperand2();
if (!initExpr || !initExpr->isBinaryOp() || initExpr->str() != "=" || !Token::Match(initExpr->astOperand1(), "%var%"))
return false;
std::vector<MathLib::bigint> minInitValue = getMinValue(makeIntegralInferModel(), initExpr->astOperand2()->values());
*varid = initExpr->astOperand1()->varId();
*knownInitValue = initExpr->astOperand2()->hasKnownIntValue();
*initValue = minInitValue.empty() ? 0 : minInitValue.front();
*partialCond = Token::Match(condExpr, "%oror%|&&");
visitAstNodes(condExpr, [varid, &condExpr](const Token *tok) {
if (Token::Match(tok, "%oror%|&&"))
return ChildrenToVisit::op1_and_op2;
if (Token::Match(tok, "<|<=") && tok->isBinaryOp() && tok->astOperand1()->varId() == *varid && tok->astOperand2()->hasKnownIntValue()) {
if (Token::Match(condExpr, "%oror%|&&") || tok->astOperand2()->getKnownIntValue() < condExpr->astOperand2()->getKnownIntValue())
condExpr = tok;
}
return ChildrenToVisit::none;
});
if (!Token::Match(condExpr, "<|<=") || !condExpr->isBinaryOp() || condExpr->astOperand1()->varId() != *varid || !condExpr->astOperand2()->hasKnownIntValue())
return false;
if (!incExpr || !incExpr->isUnaryOp("++") || incExpr->astOperand1()->varId() != *varid)
return false;
*stepValue = 1;
if (condExpr->str() == "<")
*lastValue = condExpr->astOperand2()->getKnownIntValue() - 1;
else
*lastValue = condExpr->astOperand2()->getKnownIntValue();
return true;
}
static const Token * getVariableInitExpression(const Variable * var)
{
if (!var)
return nullptr;
const Token *varDeclEndToken = var->declEndToken();
if (!varDeclEndToken)
return nullptr;
if (Token::Match(varDeclEndToken, "; %varid% =", var->declarationId()))
return varDeclEndToken->tokAt(2)->astOperand2();
return varDeclEndToken->astOperand2();
}
static bool isInLoopCondition(const Token * tok)
{
return Token::Match(tok->astTop()->previous(), "for|while (");
}
/// If tok2 comes after tok1
bool precedes(const Token * tok1, const Token * tok2)
{
if (tok1 == tok2)
return false;
if (!tok1)
return false;
if (!tok2)
return true;
return tok1->index() < tok2->index();
}
/// If tok1 comes after tok2
bool succeeds(const Token* tok1, const Token* tok2)
{
if (tok1 == tok2)
return false;
if (!tok1)
return false;
if (!tok2)
return true;
return tok1->index() > tok2->index();
}
bool isAliasOf(const Token *tok, nonneg int varid, bool* inconclusive)
{
if (tok->varId() == varid)
return false;
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isLocalLifetimeValue())
continue;
if (val.tokvalue->varId() == varid) {
if (val.isInconclusive()) {
if (inconclusive)
*inconclusive = true;
else
continue;
}
return true;
}
}
return false;
}
static bool isAliased(const Token *startTok, const Token *endTok, nonneg int varid)
{
if (!precedes(startTok, endTok))
return false;
for (const Token *tok = startTok; tok != endTok; tok = tok->next()) {
if (Token::Match(tok, "= & %varid% ;", varid))
return true;
if (isAliasOf(tok, varid))
return true;
}
return false;
}
bool isAliased(const Variable *var)
{
if (!var)
return false;
if (!var->scope())
return false;
const Token *start = var->declEndToken();
if (!start)
return false;
return isAliased(start, var->scope()->bodyEnd, var->declarationId());
}
bool exprDependsOnThis(const Token* expr, bool onVar, nonneg int depth)
{
if (!expr)
return false;
if (expr->str() == "this")
return true;
if (depth >= 1000)
// Abort recursion to avoid stack overflow
return true;
++depth;
// calling nonstatic method?
if (Token::Match(expr->previous(), "!!:: %name% (") && expr->function() && expr->function()->nestedIn &&
expr->function()->nestedIn->isClassOrStruct()) {
// is it a method of this?
const Scope* fScope = expr->scope();
while (!fScope->functionOf && fScope->nestedIn)
fScope = fScope->nestedIn;
const Scope* classScope = fScope->functionOf;
if (classScope && classScope->function)
classScope = classScope->function->token->scope();
if (classScope && classScope->isClassOrStruct())
return contains(classScope->findAssociatedScopes(), expr->function()->nestedIn);
return false;
} else if (onVar && Token::Match(expr, "%var%") && expr->variable()) {
const Variable* var = expr->variable();
return (var->isPrivate() || var->isPublic() || var->isProtected());
}
if (Token::simpleMatch(expr, "."))
return exprDependsOnThis(expr->astOperand1(), onVar, depth);
return exprDependsOnThis(expr->astOperand1(), onVar, depth) || exprDependsOnThis(expr->astOperand2(), onVar, depth);
}
static bool hasUnknownVars(const Token* startTok)
{
bool result = false;
visitAstNodes(startTok, [&](const Token* tok) {
if (tok->varId() > 0 && !tok->variable()) {
result = true;
return ChildrenToVisit::done;
}
return ChildrenToVisit::op1_and_op2;
});
return result;
}
static bool isStructuredBindingVariable(const Variable* var)
{
if (!var)
return false;
const Token* tok = var->nameToken();
while (Token::Match(tok->astParent(), "[|,"))
tok = tok->astParent();
return Token::simpleMatch(tok, "[");
}
/// This takes a token that refers to a variable and it will return the token
/// to the expression that the variable is assigned to. If its not valid to
/// make such substitution then it will return the original token.
static const Token * followVariableExpression(const Token * tok, bool cpp, const Token * end = nullptr)
{
if (!tok)
return tok;
// Skip following variables that is across multiple files
if (end && end->fileIndex() != tok->fileIndex())
return tok;
// Skip array access
if (Token::Match(tok, "%var% ["))
return tok;
// Skip pointer indirection
if (tok->astParent() && tok->isUnaryOp("*"))
return tok;
// Skip following variables if it is used in an assignment
if (Token::Match(tok->next(), "%assign%"))
return tok;
const Variable * var = tok->variable();
const Token * varTok = getVariableInitExpression(var);
if (!varTok)
return tok;
if (hasUnknownVars(varTok))
return tok;
if (var->isVolatile())
return tok;
if (!var->isLocal() && !var->isConst())
return tok;
if (var->isStatic() && !var->isConst())
return tok;
if (var->isArgument())
return tok;
if (isStructuredBindingVariable(var))
return tok;
// assigning a floating point value to an integer does not preserve the value
if (var->valueType() && var->valueType()->isIntegral() && varTok->valueType() && varTok->valueType()->isFloat())
return tok;
const Token * lastTok = precedes(tok, end) ? end : tok;
// If this is in a loop then check if variables are modified in the entire scope
const Token * endToken = (isInLoopCondition(tok) || isInLoopCondition(varTok) || var->scope() != tok->scope()) ? var->scope()->bodyEnd : lastTok;
if (!var->isConst() && (!precedes(varTok, endToken) || isVariableChanged(varTok, endToken, tok->varId(), false, nullptr, cpp)))
return tok;
if (precedes(varTok, endToken) && isAliased(varTok, endToken, tok->varId()))
return tok;
const Token* startToken = nextAfterAstRightmostLeaf(varTok);
if (!startToken)
startToken = varTok;
if (varTok->exprId() == 0) {
if (!varTok->isLiteral())
return tok;
} else if (!precedes(startToken, endToken)) {
return tok;
} else if (isExpressionChanged(varTok, startToken, endToken, nullptr, cpp)) {
return tok;
}
return varTok;
}
static void followVariableExpressionError(const Token *tok1, const Token *tok2, ErrorPath* errors)
{
if (!errors)
return;
if (!tok1)
return;
if (!tok2)
return;
ErrorPathItem item = std::make_pair(tok2, "'" + tok1->str() + "' is assigned value '" + tok2->expressionString() + "' here.");
if (std::find(errors->begin(), errors->end(), item) != errors->end())
return;
errors->push_back(item);
}
std::vector<ReferenceToken> followAllReferences(const Token* tok,
bool temporary,
bool inconclusive,
ErrorPath errors,
int depth)
{
struct ReferenceTokenLess {
bool operator()(const ReferenceToken& x, const ReferenceToken& y) const {
return x.token < y.token;
}
};
if (!tok)
return std::vector<ReferenceToken> {};
if (depth < 0)
return {{tok, std::move(errors)}};
const Variable *var = tok->variable();
if (var && var->declarationId() == tok->varId()) {
if (var->nameToken() == tok || isStructuredBindingVariable(var)) {
return {{tok, std::move(errors)}};
} else if (var->isReference() || var->isRValueReference()) {
if (!var->declEndToken())
return {{tok, std::move(errors)}};
if (var->isArgument()) {
errors.emplace_back(var->declEndToken(), "Passed to reference.");
return {{tok, std::move(errors)}};
} else if (Token::simpleMatch(var->declEndToken(), "=")) {
if (astHasToken(var->declEndToken(), tok))
return std::vector<ReferenceToken>{};
errors.emplace_back(var->declEndToken(), "Assigned to reference.");
const Token *vartok = var->declEndToken()->astOperand2();
if (vartok == tok || (!temporary && isTemporary(true, vartok, nullptr, true) &&
(var->isConst() || var->isRValueReference())))
return {{tok, std::move(errors)}};
if (vartok)
return followAllReferences(vartok, temporary, inconclusive, std::move(errors), depth - 1);
} else {
return {{tok, std::move(errors)}};
}
}
} else if (Token::simpleMatch(tok, "?") && Token::simpleMatch(tok->astOperand2(), ":")) {
std::set<ReferenceToken, ReferenceTokenLess> result;
const Token* tok2 = tok->astOperand2();
std::vector<ReferenceToken> refs;
refs = followAllReferences(tok2->astOperand1(), temporary, inconclusive, errors, depth - 1);
result.insert(refs.begin(), refs.end());
refs = followAllReferences(tok2->astOperand2(), temporary, inconclusive, errors, depth - 1);
result.insert(refs.begin(), refs.end());
if (!inconclusive && result.size() != 1)
return {{tok, std::move(errors)}};
if (!result.empty())
return std::vector<ReferenceToken>(result.begin(), result.end());
} else if (Token::Match(tok->previous(), "%name% (")) {
const Function *f = tok->previous()->function();
if (f) {
if (!Function::returnsReference(f))
return {{tok, std::move(errors)}};
std::set<ReferenceToken, ReferenceTokenLess> result;
std::vector<const Token*> returns = Function::findReturns(f);
for (const Token* returnTok : returns) {
if (returnTok == tok)
continue;
for (const ReferenceToken& rt :
followAllReferences(returnTok, temporary, inconclusive, errors, depth - returns.size())) {
const Variable* argvar = rt.token->variable();
if (!argvar)
return {{tok, std::move(errors)}};
if (argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) {
int n = getArgumentPos(argvar, f);
if (n < 0)
return {{tok, std::move(errors)}};
std::vector<const Token*> args = getArguments(tok->previous());
if (n >= args.size())
return {{tok, std::move(errors)}};
const Token* argTok = args[n];
ErrorPath er = errors;
er.emplace_back(returnTok, "Return reference.");
er.emplace_back(tok->previous(), "Called function passing '" + argTok->expressionString() + "'.");
std::vector<ReferenceToken> refs =
followAllReferences(argTok, temporary, inconclusive, std::move(er), depth - returns.size());
result.insert(refs.begin(), refs.end());
if (!inconclusive && result.size() > 1)
return {{tok, std::move(errors)}};
}
}
}
if (!result.empty())
return std::vector<ReferenceToken>(result.begin(), result.end());
}
}
return {{tok, std::move(errors)}};
}
const Token* followReferences(const Token* tok, ErrorPath* errors)
{
if (!tok)
return nullptr;
std::vector<ReferenceToken> refs = followAllReferences(tok, true, false);
if (refs.size() == 1) {
if (errors)
*errors = refs.front().errors;
return refs.front().token;
}
return nullptr;
}
static bool isSameLifetime(const Token * const tok1, const Token * const tok2)
{
ValueFlow::Value v1 = getLifetimeObjValue(tok1);
ValueFlow::Value v2 = getLifetimeObjValue(tok2);
if (!v1.isLifetimeValue() || !v2.isLifetimeValue())
return false;
return v1.tokvalue == v2.tokvalue;
}
static bool compareKnownValue(const Token * const tok1, const Token * const tok2, std::function<bool(const ValueFlow::Value&, const ValueFlow::Value&, bool)> compare)
{
static const auto isKnownFn = std::mem_fn(&ValueFlow::Value::isKnown);
const auto v1 = std::find_if(tok1->values().begin(), tok1->values().end(), isKnownFn);
if (v1 == tok1->values().end()) {
return false;
}
if (v1->isNonValue() || v1->isContainerSizeValue() || v1->isSymbolicValue())
return false;
const auto v2 = std::find_if(tok2->values().begin(), tok2->values().end(), isKnownFn);
if (v2 == tok2->values().end()) {
return false;
}
if (v1->valueType != v2->valueType) {
return false;
}
const bool sameLifetime = isSameLifetime(tok1, tok2);
return compare(*v1, *v2, sameLifetime);
}
bool isEqualKnownValue(const Token * const tok1, const Token * const tok2)
{
return compareKnownValue(tok1, tok2, [&](const ValueFlow::Value& v1, const ValueFlow::Value& v2, bool sameLifetime) {
bool r = v1.equalValue(v2);
if (v1.isIteratorValue()) {
r &= sameLifetime;
}
return r;
});
}
static inline bool isDifferentKnownValues(const Token * const tok1, const Token * const tok2)
{
return compareKnownValue(tok1, tok2, [&](const ValueFlow::Value& v1, const ValueFlow::Value& v2, bool sameLifetime) {
bool r = v1.equalValue(v2);
if (v1.isIteratorValue()) {
r &= sameLifetime;
}
return !r;
});
}
static inline bool isSameConstantValue(bool macro, const Token * const tok1, const Token * const tok2)
{
if (tok1 == nullptr || tok2 == nullptr)
return false;
if (!tok1->isNumber() || !tok2->isNumber())
return false;
if (macro && (tok1->isExpandedMacro() || tok2->isExpandedMacro() || tok1->isTemplateArg() || tok2->isTemplateArg()))
return false;
const ValueType * v1 = tok1->valueType();
const ValueType * v2 = tok2->valueType();
if (!v1 || !v2 || v1->sign != v2->sign || v1->type != v2->type || v1->pointer != v2->pointer)
return false;
return isEqualKnownValue(tok1, tok2);
}
static bool isForLoopCondition(const Token * const tok)
{
if (!tok)
return false;
const Token *const parent = tok->astParent();
return Token::simpleMatch(parent, ";") && parent->astOperand1() == tok &&
Token::simpleMatch(parent->astParent(), ";") &&
Token::simpleMatch(parent->astParent()->astParent(), "(") &&
parent->astParent()->astParent()->astOperand1()->str() == "for";
}
static bool isZeroConstant(const Token *tok)
{
while (tok && tok->isCast())
tok = tok->astOperand2() ? tok->astOperand2() : tok->astOperand1();
return Token::simpleMatch(tok, "0") && !tok->isExpandedMacro();
}
/**
* Is token used a boolean (cast to a bool, or used as a condition somewhere)
* @param tok the token to check
* @param checkingParent true if we are checking a parent. This is used to know
* what we are checking. For instance in `if (i == 2)`, isUsedAsBool("==") is
* true whereas isUsedAsBool("i") is false, but it might call
* isUsedAsBool_internal("==") which must not return true
*/
static bool isUsedAsBool_internal(const Token * const tok, bool checkingParent)
{
if (!tok)
return false;
const Token::Type type = tok->tokType();
if (type == Token::eBitOp || type == Token::eIncDecOp || (type == Token::eArithmeticalOp && !tok->isUnaryOp("*")))
// those operators don't return a bool
return false;
if (type == Token::eComparisonOp) {
if (!checkingParent)
// this operator returns a bool
return true;
if (Token::Match(tok, "==|!="))
return isZeroConstant(tok->astOperand1()) || isZeroConstant(tok->astOperand2());
return false;
}
if (type == Token::eLogicalOp)
return true;
if (astIsBool(tok))
return true;
const Token * const parent = tok->astParent();
if (!parent)
return false;
if (parent->str() == "(" && parent->astOperand2() == tok) {
if (Token::Match(parent->astOperand1(), "if|while"))
return true;
if (!parent->isCast()) { // casts are handled via the recursive call, as astIsBool will be true
// is it a call to a function ?
int argnr;
const Token *const func = getTokenArgumentFunction(tok, argnr);
if (!func || !func->function())
return false;
const Variable *var = func->function()->getArgumentVar(argnr);
return var && (var->getTypeName() == "bool");
}
} else if (isForLoopCondition(tok))
return true;
else if (Token::simpleMatch(parent, "?") && astIsLHS(tok))
return true;
return isUsedAsBool_internal(parent, true);
}
bool isUsedAsBool(const Token * const tok)
{
return isUsedAsBool_internal(tok, false);
}
static bool astIsBoolLike(const Token* tok)
{
return astIsBool(tok) || isUsedAsBool(tok);
}
bool isSameExpression(bool cpp, bool macro, const Token *tok1, const Token *tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors)
{
if (tok1 == nullptr && tok2 == nullptr)
return true;
if (tok1 == nullptr || tok2 == nullptr)
return false;
if (cpp) {
if (tok1->str() == "." && tok1->astOperand1() && tok1->astOperand1()->str() == "this")
tok1 = tok1->astOperand2();
if (tok2->str() == "." && tok2->astOperand1() && tok2->astOperand1()->str() == "this")
tok2 = tok2->astOperand2();
}
// Skip double not
if (Token::simpleMatch(tok1, "!") && Token::simpleMatch(tok1->astOperand1(), "!") && !Token::simpleMatch(tok1->astParent(), "=")) {
return isSameExpression(cpp, macro, tok1->astOperand1()->astOperand1(), tok2, library, pure, followVar, errors);
}
if (Token::simpleMatch(tok2, "!") && Token::simpleMatch(tok2->astOperand1(), "!") && !Token::simpleMatch(tok2->astParent(), "=")) {
return isSameExpression(cpp, macro, tok1, tok2->astOperand1()->astOperand1(), library, pure, followVar, errors);
}
const bool tok_str_eq = tok1->str() == tok2->str();
if (!tok_str_eq && isDifferentKnownValues(tok1, tok2))
return false;
if (isSameConstantValue(macro, tok1, tok2))
return true;
// Follow variable
if (followVar && !tok_str_eq && (Token::Match(tok1, "%var%") || Token::Match(tok2, "%var%"))) {
const Token * varTok1 = followVariableExpression(tok1, cpp, tok2);
if ((varTok1->str() == tok2->str()) || isSameConstantValue(macro, varTok1, tok2)) {
followVariableExpressionError(tok1, varTok1, errors);
return isSameExpression(cpp, macro, varTok1, tok2, library, true, followVar, errors);
}
const Token * varTok2 = followVariableExpression(tok2, cpp, tok1);
if ((tok1->str() == varTok2->str()) || isSameConstantValue(macro, tok1, varTok2)) {
followVariableExpressionError(tok2, varTok2, errors);
return isSameExpression(cpp, macro, tok1, varTok2, library, true, followVar, errors);
}
if ((varTok1->str() == varTok2->str()) || isSameConstantValue(macro, varTok1, varTok2)) {
followVariableExpressionError(tok1, varTok1, errors);
followVariableExpressionError(tok2, varTok2, errors);
return isSameExpression(cpp, macro, varTok1, varTok2, library, true, followVar, errors);
}
}
// Follow references
if (!tok_str_eq) {
const Token* refTok1 = followReferences(tok1, errors);
const Token* refTok2 = followReferences(tok2, errors);
if (refTok1 != tok1 || refTok2 != tok2)
return isSameExpression(cpp, macro, refTok1, refTok2, library, pure, followVar, errors);
}
if (tok1->varId() != tok2->varId() || !tok_str_eq || tok1->originalName() != tok2->originalName()) {
if ((Token::Match(tok1,"<|>") && Token::Match(tok2,"<|>")) ||
(Token::Match(tok1,"<=|>=") && Token::Match(tok2,"<=|>="))) {
return isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand2(), library, pure, followVar, errors) &&
isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand1(), library, pure, followVar, errors);
}
const Token* condTok = nullptr;
const Token* exprTok = nullptr;
if (Token::Match(tok1, "==|!=")) {
condTok = tok1;
exprTok = tok2;
} else if (Token::Match(tok2, "==|!=")) {
condTok = tok2;
exprTok = tok1;
}
if (condTok && condTok->astOperand1() && condTok->astOperand2() && !Token::Match(exprTok, "%comp%")) {
const Token* varTok1 = nullptr;
const Token* varTok2 = exprTok;
const ValueFlow::Value* value = nullptr;
if (condTok->astOperand1()->hasKnownIntValue()) {
value = &condTok->astOperand1()->values().front();
varTok1 = condTok->astOperand2();
} else if (condTok->astOperand2()->hasKnownIntValue()) {
value = &condTok->astOperand2()->values().front();
varTok1 = condTok->astOperand1();
}
if (Token::simpleMatch(exprTok, "!"))
varTok2 = exprTok->astOperand1();
bool compare = false;
if (value) {
if (value->intvalue == 0 && Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "==")) {
compare = true;
} else if (value->intvalue == 0 && !Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "!=")) {
compare = true;
} else if (value->intvalue != 0 && Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "!=")) {
compare = true;
} else if (value->intvalue != 0 && !Token::simpleMatch(exprTok, "!") && Token::simpleMatch(condTok, "==")) {
compare = true;
}
}
if (compare && astIsBoolLike(varTok1) && astIsBoolLike(varTok2))
return isSameExpression(cpp, macro, varTok1, varTok2, library, pure, followVar, errors);
}
return false;
}
auto flagsDiffer = [](const Token* tok1, const Token* tok2, bool macro) {
if (macro && (tok1->isExpandedMacro() || tok2->isExpandedMacro() || tok1->isTemplateArg() || tok2->isTemplateArg()))
return true;
if (tok1->isComplex() != tok2->isComplex())
return true;
if (tok1->isLong() != tok2->isLong())
return true;
if (tok1->isUnsigned() != tok2->isUnsigned())
return true;
if (tok1->isSigned() != tok2->isSigned())
return true;
return false;
};
if (flagsDiffer(tok1, tok2, macro))
return false;
if (pure && tok1->isName() && tok1->next()->str() == "(" && tok1->str() != "sizeof" && !(tok1->variable() && tok1 == tok1->variable()->nameToken())) {
if (!tok1->function()) {
if (Token::simpleMatch(tok1->previous(), ".")) {
const Token *lhs = tok1->previous();
while (Token::Match(lhs, "(|.|["))
lhs = lhs->astOperand1();
if (!lhs)
return false;
const bool lhsIsConst = (lhs->variable() && lhs->variable()->isConst()) ||
(lhs->valueType() && lhs->valueType()->constness > 0) ||
(Token::Match(lhs, "%var% . %name% (") && library.isFunctionConst(lhs->tokAt(2)));
if (!lhsIsConst)
return false;
} else {
const Token * ftok = tok1;
if (Token::simpleMatch(tok1->previous(), "::"))
ftok = tok1->previous();
if (!library.isFunctionConst(ftok) && !ftok->isAttributeConst() && !ftok->isAttributePure())
return false;
}
} else {
if (tok1->function() && !tok1->function()->isConst() && !tok1->function()->isAttributeConst() && !tok1->function()->isAttributePure())
return false;
}
}
// templates/casts
if ((Token::Match(tok1, "%name% <") && tok1->next()->link()) ||
(Token::Match(tok2, "%name% <") && tok2->next()->link())) {
// non-const template function that is not a dynamic_cast => return false
if (pure && Token::simpleMatch(tok1->next()->link(), "> (") &&
!(tok1->function() && tok1->function()->isConst()) &&
tok1->str() != "dynamic_cast")
return false;
// some template/cast stuff.. check that the template arguments are same
const Token *t1 = tok1->next();
const Token *t2 = tok2->next();
const Token *end1 = t1->link();
const Token *end2 = t2->link();
while (t1 && t2 && t1 != end1 && t2 != end2) {
if (t1->str() != t2->str() || flagsDiffer(t1, t2, macro))
return false;
t1 = t1->next();
t2 = t2->next();
}
if (t1 != end1 || t2 != end2)
return false;
}
if (tok1->tokType() == Token::eIncDecOp || tok1->isAssignmentOp())
return false;
// bailout when we see ({..})
if (tok1->str() == "{")
return false;
// cast => assert that the casts are equal
if (tok1->str() == "(" && tok1->previous() &&
!tok1->previous()->isName() &&
!(tok1->previous()->str() == ">" && tok1->previous()->link())) {
const Token *t1 = tok1->next();
const Token *t2 = tok2->next();
while (t1 && t2 &&
t1->str() == t2->str() &&
!flagsDiffer(t1, t2, macro) &&
(t1->isName() || t1->str() == "*")) {
t1 = t1->next();
t2 = t2->next();
}
if (!t1 || !t2 || t1->str() != ")" || t2->str() != ")")
return false;
}
bool noncommutativeEquals =
isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand1(), library, pure, followVar, errors);
noncommutativeEquals = noncommutativeEquals &&
isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand2(), library, pure, followVar, errors);
if (noncommutativeEquals)
return true;
// in c++, a+b might be different to b+a, depending on the type of a and b
if (cpp && tok1->str() == "+" && tok1->isBinaryOp()) {
const ValueType* vt1 = tok1->astOperand1()->valueType();
const ValueType* vt2 = tok1->astOperand2()->valueType();
if (!(vt1 && (vt1->type >= ValueType::VOID || vt1->pointer) && vt2 && (vt2->type >= ValueType::VOID || vt2->pointer)))
return false;
}
const bool commutative = tok1->isBinaryOp() && Token::Match(tok1, "%or%|%oror%|+|*|&|&&|^|==|!=");
bool commutativeEquals = commutative &&
isSameExpression(cpp, macro, tok1->astOperand2(), tok2->astOperand1(), library, pure, followVar, errors);
commutativeEquals = commutativeEquals &&
isSameExpression(cpp, macro, tok1->astOperand1(), tok2->astOperand2(), library, pure, followVar, errors);
return commutativeEquals;
}
static bool isZeroBoundCond(const Token * const cond)
{
if (cond == nullptr)
return false;
// Assume unsigned
// TODO: Handle reverse conditions
const bool isZero = cond->astOperand2()->getValue(0);
if (cond->str() == "==" || cond->str() == ">=")
return isZero;
if (cond->str() == "<=")
return true;
if (cond->str() == "<")
return !isZero;
if (cond->str() == ">")
return false;
return false;
}
bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const Library& library, bool pure, bool followVar, ErrorPath* errors)
{
if (!cond1 || !cond2)
return false;
if (!isNot && cond1->str() == "&&" && cond2->str() == "&&") {
for (const Token* tok1: {
cond1->astOperand1(), cond1->astOperand2()
}) {
for (const Token* tok2: {
cond2->astOperand1(), cond2->astOperand2()
}) {
if (isSameExpression(cpp, true, tok1, tok2, library, pure, followVar, errors)) {
if (isOppositeCond(isNot, cpp, tok1->astSibling(), tok2->astSibling(), library, pure, followVar, errors))
return true;
}
}
}
}
if (cond1->str() == "!") {
if (cond2->str() == "!=") {
if (cond2->astOperand1() && cond2->astOperand1()->str() == "0")
return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), library, pure, followVar, errors);
if (cond2->astOperand2() && cond2->astOperand2()->str() == "0")
return isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors);
}
if (!isUsedAsBool(cond2))
return false;
return isSameExpression(cpp, true, cond1->astOperand1(), cond2, library, pure, followVar, errors);
}
if (cond2->str() == "!")
return isOppositeCond(isNot, cpp, cond2, cond1, library, pure, followVar, errors);
if (!isNot) {
if (cond1->str() == "==" && cond2->str() == "==") {
if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors))
return isDifferentKnownValues(cond1->astOperand2(), cond2->astOperand2());
if (isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), library, pure, followVar, errors))
return isDifferentKnownValues(cond1->astOperand1(), cond2->astOperand1());
}
// TODO: Handle reverse conditions
if (Library::isContainerYield(cond1, Library::Container::Yield::EMPTY, "empty") &&
Library::isContainerYield(cond2->astOperand1(), Library::Container::Yield::SIZE, "size") &&
isSameExpression(cpp,
true,
cond1->astOperand1()->astOperand1(),
cond2->astOperand1()->astOperand1()->astOperand1(),
library,
pure,
followVar,
errors)) {
return !isZeroBoundCond(cond2);
}
if (Library::isContainerYield(cond2, Library::Container::Yield::EMPTY, "empty") &&
Library::isContainerYield(cond1->astOperand1(), Library::Container::Yield::SIZE, "size") &&
isSameExpression(cpp,
true,
cond2->astOperand1()->astOperand1(),
cond1->astOperand1()->astOperand1()->astOperand1(),
library,
pure,
followVar,
errors)) {
return !isZeroBoundCond(cond1);
}
}
if (!cond1->isComparisonOp() || !cond2->isComparisonOp())
return false;
const std::string &comp1 = cond1->str();
// condition found .. get comparator
std::string comp2;
if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand1(), library, pure, followVar, errors) &&
isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand2(), library, pure, followVar, errors)) {
comp2 = cond2->str();
} else if (isSameExpression(cpp, true, cond1->astOperand1(), cond2->astOperand2(), library, pure, followVar, errors) &&
isSameExpression(cpp, true, cond1->astOperand2(), cond2->astOperand1(), library, pure, followVar, errors)) {
comp2 = cond2->str();
if (comp2[0] == '>')
comp2[0] = '<';
else if (comp2[0] == '<')
comp2[0] = '>';
}
if (!isNot && comp2.empty()) {
const Token *expr1 = nullptr, *value1 = nullptr, *expr2 = nullptr, *value2 = nullptr;
std::string op1 = cond1->str(), op2 = cond2->str();
if (cond1->astOperand2()->hasKnownIntValue()) {
expr1 = cond1->astOperand1();
value1 = cond1->astOperand2();
} else if (cond1->astOperand1()->hasKnownIntValue()) {
expr1 = cond1->astOperand2();
value1 = cond1->astOperand1();
if (op1[0] == '>')
op1[0] = '<';
else if (op1[0] == '<')
op1[0] = '>';
}
if (cond2->astOperand2()->hasKnownIntValue()) {
expr2 = cond2->astOperand1();
value2 = cond2->astOperand2();
} else if (cond2->astOperand1()->hasKnownIntValue()) {
expr2 = cond2->astOperand2();
value2 = cond2->astOperand1();
if (op2[0] == '>')
op2[0] = '<';
else if (op2[0] == '<')
op2[0] = '>';
}
if (!expr1 || !value1 || !expr2 || !value2) {
return false;
}
if (!isSameExpression(cpp, true, expr1, expr2, library, pure, followVar, errors))
return false;
const ValueFlow::Value &rhsValue1 = value1->values().front();
const ValueFlow::Value &rhsValue2 = value2->values().front();
if (op1 == "<" || op1 == "<=")
return (op2 == "==" || op2 == ">" || op2 == ">=") && (rhsValue1.intvalue < rhsValue2.intvalue);
else if (op1 == ">=" || op1 == ">")
return (op2 == "==" || op2 == "<" || op2 == "<=") && (rhsValue1.intvalue > rhsValue2.intvalue);
return false;
}
// is condition opposite?
return ((comp1 == "==" && comp2 == "!=") ||
(comp1 == "!=" && comp2 == "==") ||
(comp1 == "<" && comp2 == ">=") ||
(comp1 == "<=" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<=") ||
(comp1 == ">=" && comp2 == "<") ||
(!isNot && ((comp1 == "<" && comp2 == ">") ||
(comp1 == ">" && comp2 == "<") ||
(comp1 == "==" && (comp2 == "!=" || comp2 == ">" || comp2 == "<")) ||
((comp1 == "!=" || comp1 == ">" || comp1 == "<") && comp2 == "==")
)));
}
bool isOppositeExpression(bool cpp, const Token * const tok1, const Token * const tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors)
{
if (!tok1 || !tok2)
return false;
if (isOppositeCond(true, cpp, tok1, tok2, library, pure, followVar, errors))
return true;
if (tok1->isUnaryOp("-") && !(tok2->astParent() && tok2->astParent()->tokType() == Token::eBitOp))
return isSameExpression(cpp, true, tok1->astOperand1(), tok2, library, pure, followVar, errors);
if (tok2->isUnaryOp("-") && !(tok2->astParent() && tok2->astParent()->tokType() == Token::eBitOp))
return isSameExpression(cpp, true, tok2->astOperand1(), tok1, library, pure, followVar, errors);
return false;
}
static bool functionModifiesArguments(const Function* f)
{
return std::any_of(f->argumentList.begin(), f->argumentList.end(), [](const Variable& var) {
if (var.isReference() || var.isPointer())
return !var.isConst();
return true;
});
}
bool isConstFunctionCall(const Token* ftok, const Library& library)
{
if (!Token::Match(ftok, "%name% ("))
return false;
if (const Function* f = ftok->function()) {
if (f->isAttributePure() || f->isAttributeConst())
return true;
// Any modified arguments
if (functionModifiesArguments(f))
return false;
if (Function::returnsVoid(f))
return false;
// Member function call
if (Token::simpleMatch(ftok->previous(), ".")) {
if (f->isConst())
return true;
// Check for const overloaded function that just return the const version
if (!Function::returnsConst(f)) {
std::vector<const Function*> fs = f->getOverloadedFunctions();
if (std::any_of(fs.begin(), fs.end(), [&](const Function* g) {
if (f == g)
return false;
if (f->argumentList.size() != g->argumentList.size())
return false;
if (functionModifiesArguments(g))
return false;
if (g->isConst() && Function::returnsConst(g))
return true;
return false;
}))
return true;
}
return false;
} else if (f->argumentList.empty()) {
return f->isConstexpr();
}
} else if (const Library::Function* lf = library.getFunction(ftok)) {
if (lf->ispure)
return true;
for (auto&& p : lf->argumentChecks) {
const Library::ArgumentChecks& ac = p.second;
if (ac.direction != Library::ArgumentChecks::Direction::DIR_IN)
return false;
}
if (Token::simpleMatch(ftok->previous(), ".")) {
if (!lf->isconst)
return false;
} else if (lf->argumentChecks.empty()) {
return false;
}
} else if (Token::Match(ftok->previous(), ". %name% (") && ftok->previous()->originalName() != "->" &&
astIsSmartPointer(ftok->previous()->astOperand1())) {
return Token::Match(ftok, "get|get_deleter ( )");
} else if (Token::Match(ftok->previous(), ". %name% (") && astIsContainer(ftok->previous()->astOperand1())) {
const Library::Container* container = ftok->previous()->astOperand1()->valueType()->container;
if (!container)
return false;
if (container->getYield(ftok->str()) != Library::Container::Yield::NO_YIELD)
return true;
if (container->getAction(ftok->str()) == Library::Container::Action::FIND)
return true;
return false;
} else {
bool memberFunction = Token::Match(ftok->previous(), ". %name% (");
bool constMember = !memberFunction;
if (Token::Match(ftok->tokAt(-2), "%var% . %name% (")) {
const Variable* var = ftok->tokAt(-2)->variable();
if (var)
constMember = var->isConst();
}
// TODO: Only check const on lvalues
std::vector<const Token*> args = getArguments(ftok);
if (memberFunction && args.empty())
return false;
return constMember && std::all_of(args.begin(), args.end(), [](const Token* tok) {
const Variable* var = tok->variable();
if (var)
return var->isConst();
return false;
});
}
return true;
}
bool isConstExpression(const Token *tok, const Library& library, bool pure, bool cpp)
{
if (!tok)
return true;
if (tok->variable() && tok->variable()->isVolatile())
return false;
if (tok->isName() && tok->next()->str() == "(") {
if (!isConstFunctionCall(tok, library))
return false;
}
if (tok->tokType() == Token::eIncDecOp)
return false;
if (tok->isAssignmentOp())
return false;
if (isLikelyStreamRead(cpp, tok))
return false;
// bailout when we see ({..})
if (tok->str() == "{")
return false;
return isConstExpression(tok->astOperand1(), library, pure, cpp) && isConstExpression(tok->astOperand2(), library, pure, cpp);
}
bool isWithoutSideEffects(bool cpp, const Token* tok, bool checkArrayAccess, bool checkReference)
{
if (!cpp)
return true;
while (tok && tok->astOperand2() && tok->astOperand2()->str() != "(")
tok = tok->astOperand2();
if (tok && tok->varId()) {
const Variable* var = tok->variable();
return var && ((!var->isClass() && (checkReference || !var->isReference())) || var->isPointer() || (checkArrayAccess ? var->isStlType() && !var->isStlType(CheckClass::stl_containers_not_const) : var->isStlType()));
}
return true;
}
bool isUniqueExpression(const Token* tok)
{
if (!tok)
return true;
if (tok->function()) {
const Function * fun = tok->function();
const Scope * scope = fun->nestedIn;
if (!scope)
return true;
const std::string returnType = fun->retType ? fun->retType->name() : fun->retDef->stringifyList(fun->tokenDef);
for (const Function& f:scope->functionList) {
if (f.type != Function::eFunction)
continue;
const std::string freturnType = f.retType ? f.retType->name() : f.retDef->stringifyList(f.returnDefEnd());
if (f.argumentList.size() == fun->argumentList.size() &&
returnType == freturnType &&
f.name() != fun->name()) {
return false;
}
}
} else if (tok->variable()) {
const Variable * var = tok->variable();
const Scope * scope = var->scope();
if (!scope)
return true;
const Type * varType = var->type();
// Iterate over the variables in scope and the parameters of the function if possible
const Function * fun = scope->function;
const std::list<Variable>* setOfVars[] = {&scope->varlist, fun ? &fun->argumentList : nullptr};
for (const std::list<Variable>* vars:setOfVars) {
if (!vars)
continue;
bool other = std::any_of(vars->cbegin(), vars->cend(), [=](const Variable &v) {
if (varType)
return v.type() && v.type()->name() == varType->name() && v.name() != var->name();
return v.isFloatingType() == var->isFloatingType() &&
v.isEnumType() == var->isEnumType() &&
v.isClass() == var->isClass() &&
v.isArray() == var->isArray() &&
v.isPointer() == var->isPointer() &&
v.name() != var->name();
});
if (other)
return false;
}
} else if (!isUniqueExpression(tok->astOperand1())) {
return false;
}
return isUniqueExpression(tok->astOperand2());
}
static bool isEscaped(const Token* tok, bool functionsScope, const Library* library)
{
if (library && library->isnoreturn(tok))
return true;
if (functionsScope)
return Token::simpleMatch(tok, "throw");
else
return Token::Match(tok, "return|throw");
}
static bool isEscapedOrJump(const Token* tok, bool functionsScope, const Library* library)
{
if (library && library->isnoreturn(tok))
return true;
if (functionsScope)
return Token::simpleMatch(tok, "throw");
else
return Token::Match(tok, "return|goto|throw|continue|break");
}
bool isEscapeFunction(const Token* ftok, const Library* library)
{
if (!Token::Match(ftok, "%name% ("))
return false;
const Function* function = ftok->function();
if (function) {
if (function->isEscapeFunction())
return true;
if (function->isAttributeNoreturn())
return true;
} else if (library) {
if (library->isnoreturn(ftok))
return true;
}
return false;
}
static bool hasNoreturnFunction(const Token* tok, const Library* library, const Token** unknownFunc)
{
if (!tok)
return false;
const Token* ftok = tok->str() == "(" ? tok->previous() : nullptr;
while (Token::simpleMatch(ftok, "("))
ftok = ftok->astOperand1();
if (ftok) {
const Function * function = ftok->function();
if (function) {
if (function->isEscapeFunction())
return true;
if (function->isAttributeNoreturn())
return true;
} else if (library && library->isnoreturn(ftok)) {
return true;
} else if (Token::Match(ftok, "exit|abort")) {
return true;
}
if (unknownFunc && !function && library && library->functions.count(library->getFunctionName(ftok)) == 0)
*unknownFunc = ftok;
return false;
} else if (tok->isConstOp()) {
return hasNoreturnFunction(tok->astOperand1(), library, unknownFunc) || hasNoreturnFunction(tok->astOperand2(), library, unknownFunc);
}
return false;
}
bool isReturnScope(const Token* const endToken, const Library* library, const Token** unknownFunc, bool functionScope)
{
if (!endToken || endToken->str() != "}")
return false;
const Token *prev = endToken->previous();
while (prev && Token::simpleMatch(prev->previous(), "; ;"))
prev = prev->previous();
if (prev && Token::simpleMatch(prev->previous(), "} ;"))
prev = prev->previous();
if (Token::simpleMatch(prev, "}")) {
if (Token::simpleMatch(prev->link()->tokAt(-2), "} else {"))
return isReturnScope(prev, library, unknownFunc, functionScope) &&
isReturnScope(prev->link()->tokAt(-2), library, unknownFunc, functionScope);
// TODO: Check all cases
if (!functionScope && Token::simpleMatch(prev->link()->previous(), ") {") &&
Token::simpleMatch(prev->link()->linkAt(-1)->previous(), "switch (") &&
!Token::findsimplematch(prev->link(), "break", prev)) {
return isReturnScope(prev, library, unknownFunc, functionScope);
}
if (isEscaped(prev->link()->astTop(), functionScope, library))
return true;
if (Token::Match(prev->link()->previous(), "[;{}] {"))
return isReturnScope(prev, library, unknownFunc, functionScope);
} else if (Token::simpleMatch(prev, ";")) {
if (prev->tokAt(-2) && hasNoreturnFunction(prev->tokAt(-2)->astTop(), library, unknownFunc))
return true;
// Unknown symbol
if (Token::Match(prev->tokAt(-2), ";|}|{ %name% ;") && prev->previous()->isIncompleteVar()) {
if (unknownFunc)
*unknownFunc = prev->previous();
return false;
}
if (Token::simpleMatch(prev->previous(), ") ;") && prev->previous()->link() &&
isEscaped(prev->previous()->link()->astTop(), functionScope, library))
return true;
if (isEscaped(prev->previous()->astTop(), functionScope, library))
return true;
// return/goto statement
prev = prev->previous();
while (prev && !Token::Match(prev, ";|{|}") && !isEscapedOrJump(prev, functionScope, library))
prev = prev->previous();
return prev && prev->isName();
}
return false;
}
bool isWithinScope(const Token* tok, const Variable* var, Scope::ScopeType type)
{
if (!tok || !var)
return false;
const Scope* scope = tok->scope();
while (scope && scope != var->scope()) {
if (scope->type == type)
return true;
scope = scope->nestedIn;
}
return false;
}
bool isVariableChangedByFunctionCall(const Token *tok, int indirect, nonneg int varid, const Settings *settings, bool *inconclusive)
{
if (!tok)
return false;
if (tok->varId() == varid)
return isVariableChangedByFunctionCall(tok, indirect, settings, inconclusive);
return isVariableChangedByFunctionCall(tok->astOperand1(), indirect, varid, settings, inconclusive) ||
isVariableChangedByFunctionCall(tok->astOperand2(), indirect, varid, settings, inconclusive);
}
bool isScopeBracket(const Token* tok)
{
if (!Token::Match(tok, "{|}"))
return false;
if (!tok->scope())
return false;
if (tok->str() == "{")
return tok->scope()->bodyStart == tok;
if (tok->str() == "}")
return tok->scope()->bodyEnd == tok;
return false;
}
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
T* getTokenArgumentFunctionImpl(T* tok, int& argn)
{
argn = -1;
{
T* parent = tok->astParent();
if (parent && parent->isUnaryOp("&"))
parent = parent->astParent();
while (parent && parent->isCast())
parent = parent->astParent();
if (Token::Match(parent, "[+-]") && parent->valueType() && parent->valueType()->pointer)
parent = parent->astParent();
// passing variable to subfunction?
if (Token::Match(parent, "[(,{]"))
;
else if (Token::simpleMatch(parent, ":")) {
while (Token::Match(parent, "[?:]"))
parent = parent->astParent();
while (Token::simpleMatch(parent, ","))
parent = parent->astParent();
if (!parent || parent->str() != "(")
return nullptr;
} else
return nullptr;
}
T* argtok = tok;
while (argtok && argtok->astParent() && (!Token::Match(argtok->astParent(), ",|(|{") || argtok->astParent()->isCast())) {
argtok = argtok->astParent();
}
if (!argtok)
return nullptr;
if (Token::simpleMatch(argtok, ","))
argtok = argtok->astOperand1();
if (Token::simpleMatch(argtok, "(") && argtok->astOperand2())
argtok = argtok->astOperand2();
tok = argtok;
while (Token::Match(tok->astParent(), ",|(|{")) {
tok = tok->astParent();
if (Token::Match(tok, "(|{"))
break;
}
argn = getArgumentPos(tok, argtok);
if (argn == -1)
return nullptr;
if (!Token::Match(tok, "{|("))
return nullptr;
if (tok->astOperand2())
tok = tok->astOperand1();
while (tok && (tok->isUnaryOp("*") || tok->str() == "["))
tok = tok->astOperand1();
while (Token::simpleMatch(tok, "."))
tok = tok->astOperand2();
while (Token::simpleMatch(tok, "::")) {
// If there is only a op1 and not op2, then this is a global scope
if (!tok->astOperand2() && tok->astOperand1()) {
tok = tok->astOperand1();
break;
}
tok = tok->astOperand2();
if (Token::simpleMatch(tok, "<") && tok->link())
tok = tok->astOperand1();
}
if (tok && tok->link() && tok->str() == ">")
tok = tok->link()->previous();
if (!Token::Match(tok, "%name%|(|{"))
return nullptr;
return tok;
}
const Token* getTokenArgumentFunction(const Token* tok, int& argn) {
return getTokenArgumentFunctionImpl(tok, argn);
}
Token* getTokenArgumentFunction(Token* tok, int& argn) {
return getTokenArgumentFunctionImpl(tok, argn);
}
std::vector<const Variable*> getArgumentVars(const Token* tok, int argnr)
{
std::vector<const Variable*> result;
if (!tok)
return result;
if (tok->function()) {
const Variable* argvar = tok->function()->getArgumentVar(argnr);
if (argvar)
return {argvar};
else
return result;
}
if (Token::Match(tok->previous(), "%type% (|{") || Token::simpleMatch(tok, "{") || tok->variable()) {
const bool constructor = Token::simpleMatch(tok, "{") || (tok->variable() && tok->variable()->nameToken() == tok);
const Type* type = Token::typeOf(tok);
if (!type)
return result;
const Scope* typeScope = type->classScope;
if (!typeScope)
return result;
// Aggregate constructor
if (Token::simpleMatch(tok, "{") && typeScope->numConstructors == 0 && argnr < typeScope->varlist.size()) {
auto it = std::next(typeScope->varlist.begin(), argnr);
return {&*it};
}
const int argCount = numberOfArguments(tok);
for (const Function &function : typeScope->functionList) {
if (function.argCount() < argCount)
continue;
if (constructor && !function.isConstructor())
continue;
if (!constructor && !Token::simpleMatch(function.token, "operator()"))
continue;
const Variable* argvar = function.getArgumentVar(argnr);
if (argvar)
result.push_back(argvar);
}
}
return result;
}
static bool isCPPCastKeyword(const Token* tok)
{
if (!tok)
return false;
return endsWith(tok->str(), "_cast");
}
static bool isTrivialConstructor(const Token* tok)
{
const Token* typeTok = nullptr;
const Type* t = Token::typeOf(tok, &typeTok);
if (t)
return false;
if (typeTok->valueType() && typeTok->valueType()->isPrimitive())
return true;
return false;
}
static bool isArray(const Token* tok)
{
if (!tok)
return false;
if (tok->variable())
return tok->variable()->isArray();
if (Token::simpleMatch(tok, "."))
return isArray(tok->astOperand2());
return false;
}
bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Settings *settings, bool *inconclusive)
{
if (!tok)
return false;
if (Token::simpleMatch(tok, ","))
return false;
const Token * const tok1 = tok;
// address of variable
if (tok->astParent() && tok->astParent()->isUnaryOp("&"))
indirect++;
int argnr;
tok = getTokenArgumentFunction(tok, argnr);
if (!tok)
return false; // not a function => variable not changed
if (Token::simpleMatch(tok, "{") && isTrivialConstructor(tok))
return false;
if (tok->isKeyword() && !isCPPCastKeyword(tok) && tok->str().compare(0,8,"operator") != 0)
return false;
// A functional cast won't modify the variable
if (Token::Match(tok, "%type% (|{") && tok->tokType() == Token::eType && astIsPrimitive(tok->next()))
return false;
const Token * parenTok = tok->next();
if (Token::simpleMatch(parenTok, "<") && parenTok->link())
parenTok = parenTok->link()->next();
const bool possiblyPassedByReference = (parenTok->next() == tok1 || Token::Match(tok1->previous(), ", %name% [,)}]"));
if (!tok->function() && !tok->variable() && Token::Match(tok, "%name%")) {
if (settings) {
const bool requireInit = settings->library.isuninitargbad(tok, 1 + argnr);
const bool requireNonNull = settings->library.isnullargbad(tok, 1 + argnr);
// Check if direction (in, out, inout) is specified in the library configuration and use that
const Library::ArgumentChecks::Direction argDirection = settings->library.getArgDirection(tok, 1 + argnr);
if (argDirection == Library::ArgumentChecks::Direction::DIR_IN)
return false;
else if (argDirection == Library::ArgumentChecks::Direction::DIR_OUT ||
argDirection == Library::ArgumentChecks::Direction::DIR_INOUT) {
if (indirect == 0 && isArray(tok1))
return true;
// Assume that if the variable must be initialized then the indirection is 1
if (indirect > 0 && requireInit && requireNonNull)
return true;
}
// if the library says 0 is invalid
// => it is assumed that parameter is an in parameter (TODO: this is a bad heuristic)
if (indirect == 0 && requireNonNull)
return false;
}
// possible pass-by-reference => inconclusive
if (possiblyPassedByReference) {
if (inconclusive != nullptr)
*inconclusive = true;
return false;
}
// Safe guess: Assume that parameter is changed by function call
return true;
}
std::vector<const Variable*> args = getArgumentVars(tok, argnr);
bool conclusive = false;
for (const Variable *arg:args) {
if (!arg)
continue;
conclusive = true;
if (indirect > 0) {
if (!arg->isConst() && arg->isPointer())
return true;
// If const is applied to the pointer, then the value can still be modified
if (Token::simpleMatch(arg->typeEndToken(), "* const"))
return true;
if (!arg->isPointer())
return true;
}
if (!arg->isConst() && arg->isReference())
return true;
}
if (!conclusive && inconclusive) {
*inconclusive = true;
}
return false;
}
bool isVariableChanged(const Token *tok, int indirect, const Settings *settings, bool cpp, int depth)
{
if (!tok)
return false;
if (indirect == 0 && isConstVarExpression(tok))
return false;
const Token *tok2 = tok;
int derefs = 0;
while (Token::simpleMatch(tok2->astParent(), "*") ||
(Token::simpleMatch(tok2->astParent(), ".") && !Token::simpleMatch(tok2->astParent()->astParent(), "(")) ||
(tok2->astParent() && tok2->astParent()->isUnaryOp("&") && !tok2->astParent()->astOperand2() && Token::simpleMatch(tok2->astParent()->astParent(), ".") && tok2->astParent()->astParent()->originalName()=="->") ||
(Token::simpleMatch(tok2->astParent(), "[") && tok2 == tok2->astParent()->astOperand1())) {
if (tok2->astParent() && (tok2->astParent()->isUnaryOp("*") || (astIsLHS(tok2) && tok2->astParent()->originalName() == "->")))
derefs++;
if (derefs > indirect)
break;
if ((tok2->astParent() && tok2->astParent()->isUnaryOp("&") && Token::simpleMatch(tok2->astParent()->astParent(), ".") && tok2->astParent()->astParent()->originalName()=="->"))
tok2 = tok2->astParent();
tok2 = tok2->astParent();
}
while (Token::simpleMatch(tok2->astParent(), "?") || (Token::simpleMatch(tok2->astParent(), ":") && Token::simpleMatch(tok2->astParent()->astParent(), "?")))
tok2 = tok2->astParent();
if (Token::Match(tok2->astParent(), "++|--"))
return true;
if (tok2->astParent() && tok2->astParent()->isAssignmentOp()) {
if (tok2 == tok2->astParent()->astOperand1())
return true;
// Check if assigning to a non-const lvalue
const Variable * var = getLHSVariable(tok2->astParent());
if (var && var->isReference() && !var->isConst() && var->nameToken() && var->nameToken()->next() == tok2->astParent()) {
if (!var->isLocal() || isVariableChanged(var, settings, cpp, depth - 1))
return true;
}
}
if (cpp && Token::Match(tok2->astParent(), ">>|&") && astIsRHS(tok2) && isLikelyStreamRead(cpp, tok2->astParent()))
return true;
if (isLikelyStream(cpp, tok2))
return true;
// Member function call
if (tok->variable() && Token::Match(tok2->astParent(), ". %name%") && isFunctionCall(tok2->astParent()->next()) && tok2->astParent()->astOperand1() == tok2) {
const Variable * var = tok->variable();
// Member function cannot change what `this` points to
if (indirect == 0 && astIsPointer(tok))
return false;
bool isConst = var && var->isConst();
if (!isConst) {
const ValueType * valueType = var->valueType();
isConst = (valueType && valueType->pointer == 1 && valueType->constness == 1);
}
if (isConst)
return false;
const Token *ftok = tok->tokAt(2);
if (settings)
return !settings->library.isFunctionConst(ftok);
const Function * fun = ftok->function();
if (!fun)
return true;
return !fun->isConst();
}
const Token *ftok = tok2;
while (ftok && (!Token::Match(ftok, "[({]") || ftok->isCast()))
ftok = ftok->astParent();
if (ftok && Token::Match(ftok->link(), ")|} !!{")) {
const Token * ptok = tok2;
while (Token::Match(ptok->astParent(), ".|::|["))
ptok = ptok->astParent();
bool inconclusive = false;
bool isChanged = isVariableChangedByFunctionCall(ptok, indirect, settings, &inconclusive);
isChanged |= inconclusive;
if (isChanged)
return true;
}
const Token *parent = tok2->astParent();
while (Token::Match(parent, ".|::"))
parent = parent->astParent();
if (parent && parent->tokType() == Token::eIncDecOp)
return true;
// structured binding, nonconst reference variable in lhs
if (Token::Match(tok2->astParent(), ":|=") && tok2 == tok2->astParent()->astOperand2() && Token::simpleMatch(tok2->astParent()->previous(), "]")) {
const Token *typeStart = tok2->astParent()->previous()->link()->previous();
if (Token::simpleMatch(typeStart, "&"))
typeStart = typeStart->previous();
if (typeStart && Token::Match(typeStart->previous(), "[;{}(] auto &| [")) {
for (const Token *vartok = typeStart->tokAt(2); vartok != tok2; vartok = vartok->next()) {
if (vartok->varId()) {
const Variable* refvar = vartok->variable();
if (!refvar || (!refvar->isConst() && refvar->isReference()))
return true;
}
}
}
}
if (Token::simpleMatch(tok2->astParent(), ":") && tok2->astParent()->astParent() && Token::simpleMatch(tok2->astParent()->astParent()->previous(), "for (")) {
// TODO: Check if container is empty or not
if (astIsLHS(tok2))
return true;
const Token * varTok = tok2->astParent()->previous();
if (!varTok)
return false;
const Variable * loopVar = varTok->variable();
if (!loopVar)
return false;
if (!loopVar->isConst() && loopVar->isReference() && isVariableChanged(loopVar, settings, cpp, depth - 1))
return true;
return false;
}
if (indirect > 0) {
// check for `*(ptr + 1) = new_value` case
parent = tok2->astParent();
while (parent && parent->isArithmeticalOp() && parent->isBinaryOp()) {
parent = parent->astParent();
}
if (Token::simpleMatch(parent, "*")) {
if (parent->astParent() && parent->astParent()->isAssignmentOp() &&
(parent->astParent()->astOperand1() == parent)) {
return true;
}
}
}
return false;
}
bool isVariableChanged(const Token *start, const Token *end, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
return findVariableChanged(start, end, 0, exprid, globalvar, settings, cpp, depth) != nullptr;
}
bool isVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
return findVariableChanged(start, end, indirect, exprid, globalvar, settings, cpp, depth) != nullptr;
}
const Token* findExpression(const Token* start, const nonneg int exprid)
{
Function * f = Scope::nestedInFunction(start->scope());
if (!f)
return nullptr;
const Scope* scope = f->functionScope;
if (!scope)
return nullptr;
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (tok->exprId() != exprid)
continue;
return tok;
}
return nullptr;
}
// Thread-unsafe memoization
template<class F, class R=decltype(std::declval<F>()())>
static std::function<R()> memoize(F f)
{
bool init = false;
R result{};
return [=]() mutable -> R {
if (init)
return result;
result = f();
init = true;
return result;
};
}
template<class F,
REQUIRES("F must be a function that returns a Token class",
std::is_convertible<decltype(std::declval<F>()()), const Token*> )>
static bool isExpressionChangedAt(const F& getExprTok,
const Token* tok,
int indirect,
const nonneg int exprid,
bool globalvar,
const Settings* settings,
bool cpp,
int depth)
{
if (depth < 0)
return true;
if (tok->exprId() != exprid) {
if (globalvar && Token::Match(tok, "%name% ("))
// TODO: Is global variable really changed by function call?
return true;
const bool pointer = astIsPointer(tok);
bool aliased = false;
// If we can't find the expression then assume it is an alias
if (!getExprTok())
aliased = true;
if (!aliased) {
aliased = findAstNode(getExprTok(), [&](const Token* childTok) {
for (const ValueFlow::Value& val : tok->values()) {
if (val.isImpossible())
continue;
if (val.isLocalLifetimeValue() || (pointer && val.isSymbolicValue() && val.intvalue == 0)) {
if (findAstNode(val.tokvalue,
[&](const Token* aliasTok) {
return aliasTok->exprId() == childTok->exprId();
}))
return true;
}
}
return false;
});
}
if (!aliased)
return false;
if (isVariableChanged(tok, 1, settings, cpp, depth))
return true;
// TODO: Try to traverse the lambda function
if (Token::Match(tok, "%var% ("))
return true;
return false;
}
return (isVariableChanged(tok, indirect, settings, cpp, depth));
}
bool isExpressionChangedAt(const Token* expr,
const Token* tok,
int indirect,
bool globalvar,
const Settings* settings,
bool cpp,
int depth)
{
return isExpressionChangedAt([&] {
return expr;
}, tok, indirect, expr->exprId(), globalvar, settings, cpp, depth);
}
Token* findVariableChanged(Token *start, const Token *end, int indirect, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
if (!precedes(start, end))
return nullptr;
if (depth < 0)
return start;
auto getExprTok = memoize([&] {
return findExpression(start, exprid);
});
for (Token *tok = start; tok != end; tok = tok->next()) {
if (isExpressionChangedAt(getExprTok, tok, indirect, exprid, globalvar, settings, cpp, depth))
return tok;
}
return nullptr;
}
const Token* findVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
return findVariableChanged(const_cast<Token*>(start), end, indirect, exprid, globalvar, settings, cpp, depth);
}
bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp, int depth)
{
if (!var)
return false;
if (!var->scope())
return false;
const Token * start = var->declEndToken();
if (!start)
return false;
if (Token::Match(start, "; %varid% =", var->declarationId()))
start = start->tokAt(2);
return isExpressionChanged(var->nameToken(), start->next(), var->scope()->bodyEnd, settings, cpp, depth);
}
bool isVariablesChanged(const Token* start,
const Token* end,
int indirect,
std::vector<const Variable*> vars,
const Settings* settings,
bool cpp)
{
std::set<int> varids;
std::transform(vars.begin(), vars.end(), std::inserter(varids, varids.begin()), [](const Variable* var) {
return var->declarationId();
});
const bool globalvar = std::any_of(vars.begin(), vars.end(), [](const Variable* var) {
return var->isGlobal();
});
for (const Token* tok = start; tok != end; tok = tok->next()) {
if (tok->varId() == 0 || varids.count(tok->varId()) == 0) {
if (globalvar && Token::Match(tok, "%name% ("))
// TODO: Is global variable really changed by function call?
return true;
continue;
}
if (isVariableChanged(tok, indirect, settings, cpp))
return true;
}
return false;
}
bool isThisChanged(const Token* tok, int indirect, const Settings* settings, bool cpp)
{
if ((Token::Match(tok->previous(), "%name% (") && !Token::simpleMatch(tok->astOperand1(), ".")) ||
Token::Match(tok->tokAt(-3), "this . %name% (")) {
if (tok->previous()->function()) {
return (!tok->previous()->function()->isConst());
} else if (!tok->previous()->isKeyword()) {
return true;
}
}
if (isVariableChanged(tok, indirect, settings, cpp))
return true;
return false;
}
bool isThisChanged(const Token* start, const Token* end, int indirect, const Settings* settings, bool cpp)
{
if (!precedes(start, end))
return false;
for (const Token* tok = start; tok != end; tok = tok->next()) {
if (!exprDependsOnThis(tok))
continue;
if (isThisChanged(tok, indirect, settings, cpp))
return true;
}
return false;
}
bool isExpressionChanged(const Token* expr, const Token* start, const Token* end, const Settings* settings, bool cpp, int depth)
{
if (depth < 0)
return true;
if (!precedes(start, end))
return false;
const Token* result = findAstNode(expr, [&](const Token* tok) {
if (exprDependsOnThis(tok) && isThisChanged(start, end, false, settings, cpp)) {
return true;
}
bool global = false;
if (tok->variable()) {
if (tok->variable()->isConst())
return false;
global = !tok->variable()->isLocal() && !tok->variable()->isArgument();
}
if (tok->exprId() > 0) {
for (const Token* tok2 = start; tok2 != end; tok2 = tok2->next()) {
if (isExpressionChangedAt(
tok, tok2, tok->valueType() ? tok->valueType()->pointer : 0, global, settings, cpp, depth))
return true;
}
}
return false;
});
return result;
}
int numberOfArguments(const Token *start)
{
int arguments=0;
const Token* const openBracket = start->next();
if (openBracket && openBracket->str()=="(" && openBracket->next() && openBracket->next()->str()!=")") {
const Token* argument=openBracket->next();
while (argument) {
++arguments;
argument = argument->nextArgument();
}
}
return arguments;
}
std::vector<const Token *> getArguments(const Token *ftok)
{
const Token* tok = ftok;
if (Token::Match(tok, "%name% (|{"))
tok = ftok->next();
if (!Token::Match(tok, "(|{|["))
return std::vector<const Token *> {};
const Token *startTok = tok->astOperand2();
if (!startTok && tok->next() != tok->link())
startTok = tok->astOperand1();
return astFlatten(startTok, ",");
}
int getArgumentPos(const Variable* var, const Function* f)
{
auto arg_it = std::find_if(f->argumentList.begin(), f->argumentList.end(), [&](const Variable& v) {
return v.nameToken() == var->nameToken();
});
if (arg_it == f->argumentList.end())
return -1;
return std::distance(f->argumentList.begin(), arg_it);
}
bool isIteratorPair(std::vector<const Token*> args)
{
return args.size() == 2 &&
((astIsIterator(args[0]) && astIsIterator(args[1])) || (astIsPointer(args[0]) && astIsPointer(args[1])));
}
const Token *findLambdaStartToken(const Token *last)
{
if (!last || last->str() != "}")
return nullptr;
const Token* tok = last->link();
if (Token::simpleMatch(tok->astParent(), "("))
tok = tok->astParent();
if (Token::simpleMatch(tok->astParent(), "["))
return tok->astParent();
return nullptr;
}
template<class T>
T* findLambdaEndTokenGeneric(T* first)
{
if (!first || first->str() != "[")
return nullptr;
if (!Token::Match(first->link(), "] (|{"))
return nullptr;
if (first->astOperand1() != first->link()->next())
return nullptr;
const Token * tok = first;
if (tok->astOperand1() && tok->astOperand1()->str() == "(")
tok = tok->astOperand1();
if (tok->astOperand1() && tok->astOperand1()->str() == "{")
return tok->astOperand1()->link();
return nullptr;
}
const Token* findLambdaEndToken(const Token* first)
{
return findLambdaEndTokenGeneric(first);
}
Token* findLambdaEndToken(Token* first)
{
return findLambdaEndTokenGeneric(first);
}
bool isLikelyStream(bool cpp, const Token *stream)
{
if (!cpp)
return false;
if (!stream)
return false;
if (!Token::Match(stream->astParent(), "&|<<|>>") || !stream->astParent()->isBinaryOp())
return false;
if (stream->astParent()->astOperand1() != stream)
return false;
return !astIsIntegral(stream, false);
}
bool isLikelyStreamRead(bool cpp, const Token *op)
{
if (!cpp)
return false;
if (!Token::Match(op, "&|>>") || !op->isBinaryOp())
return false;
if (!Token::Match(op->astOperand2(), "%name%|.|*|[") && op->str() != op->astOperand2()->str())
return false;
const Token *parent = op;
while (parent->astParent() && parent->astParent()->str() == op->str())
parent = parent->astParent();
if (parent->astParent() && !Token::Match(parent->astParent(), "%oror%|&&|(|,|.|!|;"))
return false;
if (op->str() == "&" && parent->astParent())
return false;
if (!parent->astOperand1() || !parent->astOperand2())
return false;
return (!parent->astOperand1()->valueType() || !parent->astOperand1()->valueType()->isIntegral());
}
bool isCPPCast(const Token* tok)
{
return tok && Token::simpleMatch(tok->previous(), "> (") && tok->astOperand2() && tok->astOperand1() && isCPPCastKeyword(tok->astOperand1());
}
bool isConstVarExpression(const Token *tok, const char* skipMatch)
{
if (!tok)
return false;
if (tok->str() == "?" && tok->astOperand2() && tok->astOperand2()->str() == ":") // ternary operator
return isConstVarExpression(tok->astOperand2()->astOperand1()) && isConstVarExpression(tok->astOperand2()->astOperand2()); // left and right of ":"
if (skipMatch && Token::Match(tok, skipMatch))
return false;
if (Token::simpleMatch(tok->previous(), "sizeof ("))
return true;
if (Token::Match(tok->previous(), "%name% (")) {
if (Token::simpleMatch(tok->astOperand1(), ".") && !isConstVarExpression(tok->astOperand1(), skipMatch))
return false;
std::vector<const Token *> args = getArguments(tok);
return std::all_of(args.begin(), args.end(), [&](const Token* t) {
return isConstVarExpression(t, skipMatch);
});
}
if (isCPPCast(tok)) {
return isConstVarExpression(tok->astOperand2(), skipMatch);
}
if (Token::Match(tok, "( %type%"))
return isConstVarExpression(tok->astOperand1(), skipMatch);
if (tok->str() == "::" && tok->hasKnownValue())
return isConstVarExpression(tok->astOperand2(), skipMatch);
if (Token::Match(tok, "%cop%|[|.")) {
if (tok->astOperand1() && !isConstVarExpression(tok->astOperand1(), skipMatch))
return false;
if (tok->astOperand2() && !isConstVarExpression(tok->astOperand2(), skipMatch))
return false;
return true;
}
if (Token::Match(tok, "%bool%|%num%|%str%|%char%|nullptr|NULL"))
return true;
if (tok->isEnumerator())
return true;
if (tok->variable())
return tok->variable()->isConst() && tok->variable()->nameToken() && tok->variable()->nameToken()->hasKnownValue();
return false;
}
static void getLHSVariablesRecursive(std::vector<const Variable*>& vars, const Token* tok)
{
if (!tok)
return;
if (vars.empty() && Token::Match(tok, "*|&|&&|[")) {
getLHSVariablesRecursive(vars, tok->astOperand1());
if (!vars.empty() || Token::simpleMatch(tok, "["))
return;
getLHSVariablesRecursive(vars, tok->astOperand2());
} else if (Token::Match(tok->previous(), "this . %var%")) {
getLHSVariablesRecursive(vars, tok->next());
} else if (Token::simpleMatch(tok, ".")) {
getLHSVariablesRecursive(vars, tok->astOperand1());
getLHSVariablesRecursive(vars, tok->astOperand2());
} else if (Token::simpleMatch(tok, "::")) {
getLHSVariablesRecursive(vars, tok->astOperand2());
} else if (tok->variable()) {
vars.push_back(tok->variable());
}
}
std::vector<const Variable*> getLHSVariables(const Token* tok)
{
std::vector<const Variable*> result;
if (!Token::Match(tok, "%assign%|(|{"))
return result;
if (!tok->astOperand1())
return result;
if (tok->astOperand1()->varId() > 0 && tok->astOperand1()->variable())
return {tok->astOperand1()->variable()};
getLHSVariablesRecursive(result, tok->astOperand1());
return result;
}
static const Token* getLHSVariableRecursive(const Token* tok)
{
if (!tok)
return nullptr;
if (Token::Match(tok, "*|&|&&|[")) {
const Token* vartok = getLHSVariableRecursive(tok->astOperand1());
if ((vartok && vartok->variable()) || Token::simpleMatch(tok, "["))
return vartok;
return getLHSVariableRecursive(tok->astOperand2());
}
if (Token::Match(tok->previous(), "this . %var%"))
return tok->next();
return tok;
}
const Variable *getLHSVariable(const Token *tok)
{
if (!Token::Match(tok, "%assign%"))
return nullptr;
if (!tok->astOperand1())
return nullptr;
if (tok->astOperand1()->varId() > 0 && tok->astOperand1()->variable())
return tok->astOperand1()->variable();
const Token* vartok = getLHSVariableRecursive(tok->astOperand1());
if (!vartok)
return nullptr;
return vartok->variable();
}
const Token* getLHSVariableToken(const Token* tok)
{
if (!Token::Match(tok, "%assign%"))
return nullptr;
if (!tok->astOperand1())
return nullptr;
if (tok->astOperand1()->varId() > 0)
return tok->astOperand1();
const Token* vartok = getLHSVariableRecursive(tok->astOperand1());
if (vartok && vartok->variable() && vartok->variable()->nameToken() == vartok)
return vartok;
return tok->astOperand1();
}
const Token* findAllocFuncCallToken(const Token *expr, const Library &library)
{
if (!expr)
return nullptr;
if (Token::Match(expr, "[+-]")) {
const Token *tok1 = findAllocFuncCallToken(expr->astOperand1(), library);
return tok1 ? tok1 : findAllocFuncCallToken(expr->astOperand2(), library);
}
if (expr->isCast())
return findAllocFuncCallToken(expr->astOperand2() ? expr->astOperand2() : expr->astOperand1(), library);
if (Token::Match(expr->previous(), "%name% (") && library.getAllocFuncInfo(expr->astOperand1()))
return expr->astOperand1();
return (Token::simpleMatch(expr, "new") && expr->astOperand1()) ? expr : nullptr;
}
static bool nonLocal(const Variable* var, bool deref)
{
return !var || (!var->isLocal() && !var->isArgument()) || (deref && var->isArgument() && var->isPointer()) || var->isStatic() || var->isReference() || var->isExtern();
}
static bool hasGccCompoundStatement(const Token *tok)
{
if (!tok)
return false;
if (tok->str() == "{" && Token::simpleMatch(tok->previous(), "( {"))
return true;
return hasGccCompoundStatement(tok->astOperand1()) || hasGccCompoundStatement(tok->astOperand2());
}
static bool hasFunctionCall(const Token *tok)
{
if (!tok)
return false;
if (Token::Match(tok, "%name% ("))
// todo, const/pure function?
return true;
return hasFunctionCall(tok->astOperand1()) || hasFunctionCall(tok->astOperand2());
}
static bool isUnchanged(const Token *startToken, const Token *endToken, const std::set<nonneg int> &exprVarIds, bool local)
{
for (const Token *tok = startToken; tok != endToken; tok = tok->next()) {
if (!local && Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {"))
// TODO: this is a quick bailout
return false;
if (tok->varId() == 0 || exprVarIds.find(tok->varId()) == exprVarIds.end())
continue;
const Token *parent = tok;
while (parent->astParent() && !parent->astParent()->isAssignmentOp() && parent->astParent()->tokType() != Token::Type::eIncDecOp) {
if (parent->str() == "," || parent->isUnaryOp("&"))
// TODO: This is a quick bailout
return false;
parent = parent->astParent();
}
if (parent->astParent()) {
if (parent->astParent()->tokType() == Token::Type::eIncDecOp)
return false;
else if (parent->astParent()->isAssignmentOp() && parent == parent->astParent()->astOperand1())
return false;
}
}
return true;
}
bool isNullOperand(const Token *expr)
{
if (!expr)
return false;
if (Token::Match(expr, "static_cast|const_cast|dynamic_cast|reinterpret_cast <"))
expr = expr->astParent();
else if (!expr->isCast())
return Token::Match(expr, "NULL|nullptr");
if (expr->valueType() && expr->valueType()->pointer == 0)
return false;
const Token *castOp = expr->astOperand2() ? expr->astOperand2() : expr->astOperand1();
return Token::Match(castOp, "NULL|nullptr") || (MathLib::isInt(castOp->str()) && MathLib::isNullValue(castOp->str()));
}
bool isGlobalData(const Token *expr, bool cpp)
{
// function call that returns reference => assume global data
if (expr && expr->str() == "(" && expr->valueType() && expr->valueType()->reference != Reference::None) {
if (expr->isBinaryOp())
return true;
if (expr->astOperand1() && precedes(expr->astOperand1(), expr))
return true;
}
bool globalData = false;
bool var = false;
visitAstNodes(expr,
[expr, cpp, &globalData, &var](const Token *tok) {
if (tok->varId())
var = true;
if (tok->varId() && !tok->variable()) {
// Bailout, this is probably global
globalData = true;
return ChildrenToVisit::none;
}
if (tok->originalName() == "->") {
// TODO check if pointer points at local data
globalData = true;
return ChildrenToVisit::none;
} else if (Token::Match(tok, "[*[]") && tok->astOperand1() && tok->astOperand1()->variable()) {
// TODO check if pointer points at local data
const Variable *lhsvar = tok->astOperand1()->variable();
const ValueType *lhstype = tok->astOperand1()->valueType();
if (lhsvar->isPointer()) {
globalData = true;
return ChildrenToVisit::none;
} else if (lhsvar->isArgument() && lhsvar->isArray()) {
globalData = true;
return ChildrenToVisit::none;
} else if (lhsvar->isArgument() && (!lhstype || (lhstype->type <= ValueType::Type::VOID && !lhstype->container))) {
globalData = true;
return ChildrenToVisit::none;
}
}
if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".") {
globalData = true;
return ChildrenToVisit::none;
}
if (tok->variable()) {
// TODO : Check references
if (tok->variable()->isReference() && tok != tok->variable()->nameToken()) {
globalData = true;
return ChildrenToVisit::none;
}
if (tok->variable()->isExtern()) {
globalData = true;
return ChildrenToVisit::none;
}
if (tok->previous()->str() != "." && !tok->variable()->isLocal() && !tok->variable()->isArgument()) {
globalData = true;
return ChildrenToVisit::none;
}
if (tok->variable()->isArgument() && tok->variable()->isPointer() && tok != expr) {
globalData = true;
return ChildrenToVisit::none;
}
if (tok->variable()->isPointerArray()) {
globalData = true;
return ChildrenToVisit::none;
}
}
// Unknown argument type => it might be some reference type..
if (cpp && tok->str() == "." && tok->astOperand1() && tok->astOperand1()->variable() && !tok->astOperand1()->valueType()) {
globalData = true;
return ChildrenToVisit::none;
}
if (Token::Match(tok, ".|["))
return ChildrenToVisit::op1;
return ChildrenToVisit::op1_and_op2;
});
return globalData || !var;
}
struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set<nonneg int> &exprVarIds, bool local, bool inInnerClass, int depth)
{
// Parse the given tokens
if (++depth > 1000)
return Result(Result::Type::BAILOUT);
for (const Token* tok = startToken; precedes(tok, endToken); tok = tok->next()) {
if (Token::simpleMatch(tok, "try {")) {
// TODO: handle try
return Result(Result::Type::BAILOUT);
}
if (Token::simpleMatch(tok, "break ;")) {
return Result(Result::Type::BREAK, tok);
}
if (Token::simpleMatch(tok, "goto"))
return Result(Result::Type::BAILOUT);
if (!inInnerClass && tok->str() == "{" && tok->scope()->isClassOrStruct()) {
// skip returns from local class definition
FwdAnalysis::Result result = checkRecursive(expr, tok, tok->link(), exprVarIds, local, true, depth);
if (result.type != Result::Type::NONE)
return result;
tok=tok->link();
}
if (tok->str() == "continue")
// TODO
return Result(Result::Type::BAILOUT);
if (const Token *lambdaEndToken = findLambdaEndToken(tok)) {
tok = lambdaEndToken;
const Result lambdaResult = checkRecursive(expr, lambdaEndToken->link()->next(), lambdaEndToken, exprVarIds, local, inInnerClass, depth);
if (lambdaResult.type == Result::Type::READ || lambdaResult.type == Result::Type::BAILOUT)
return lambdaResult;
}
if (Token::Match(tok, "return|throw")) {
// TODO: Handle these better
// Is expr variable used in expression?
const Token* opTok = tok->astOperand1();
if (!opTok)
opTok = tok->next();
std::pair<const Token*, const Token*> startEndTokens = opTok->findExpressionStartEndTokens();
FwdAnalysis::Result result =
checkRecursive(expr, startEndTokens.first, startEndTokens.second->next(), exprVarIds, local, true, depth);
if (result.type != Result::Type::NONE)
return result;
// #9167: if the return is inside an inner class, it does not tell us anything
if (!inInnerClass) {
if (!local && mWhat == What::Reassign)
return Result(Result::Type::BAILOUT);
return Result(Result::Type::RETURN);
}
}
if (tok->str() == "}") {
// Known value => possible value
if (tok->scope() == expr->scope())
mValueFlowKnown = false;
if (tok->scope()->isLoopScope()) {
// check condition
const Token *conditionStart = nullptr;
const Token *conditionEnd = nullptr;
if (Token::simpleMatch(tok->link()->previous(), ") {")) {
conditionEnd = tok->link()->previous();
conditionStart = conditionEnd->link();
} else if (Token::simpleMatch(tok->link()->previous(), "do {") && Token::simpleMatch(tok, "} while (")) {
conditionStart = tok->tokAt(2);
conditionEnd = conditionStart->link();
}
if (conditionStart && conditionEnd) {
bool used = false;
for (const Token *condTok = conditionStart; condTok != conditionEnd; condTok = condTok->next()) {
if (exprVarIds.find(condTok->varId()) != exprVarIds.end()) {
used = true;
break;
}
}
if (used)
return Result(Result::Type::BAILOUT);
}
// check loop body again..
const struct FwdAnalysis::Result &result = checkRecursive(expr, tok->link(), tok, exprVarIds, local, inInnerClass, depth);
if (result.type == Result::Type::BAILOUT || result.type == Result::Type::READ)
return result;
}
}
if (Token::simpleMatch(tok, "else {"))
tok = tok->linkAt(1);
if (Token::simpleMatch(tok, "asm ("))
return Result(Result::Type::BAILOUT);
if (mWhat == What::ValueFlow && (Token::Match(tok, "while|for (") || Token::simpleMatch(tok, "do {"))) {
const Token *bodyStart = nullptr;
const Token *conditionStart = nullptr;
if (Token::simpleMatch(tok, "do {")) {
bodyStart = tok->next();
if (Token::simpleMatch(bodyStart->link(), "} while ("))
conditionStart = bodyStart->link()->tokAt(2);
} else {
conditionStart = tok->next();
if (Token::simpleMatch(conditionStart->link(), ") {"))
bodyStart = conditionStart->link()->next();
}
if (!bodyStart || !conditionStart)
return Result(Result::Type::BAILOUT);
// Is expr changed in condition?
if (!isUnchanged(conditionStart, conditionStart->link(), exprVarIds, local))
return Result(Result::Type::BAILOUT);
// Is expr changed in loop body?
if (!isUnchanged(bodyStart, bodyStart->link(), exprVarIds, local))
return Result(Result::Type::BAILOUT);
}
if (mWhat == What::ValueFlow && Token::simpleMatch(tok, "if (") && Token::simpleMatch(tok->linkAt(1), ") {")) {
const Token *bodyStart = tok->linkAt(1)->next();
const Token *conditionStart = tok->next();
const Token *condTok = conditionStart->astOperand2();
if (condTok->hasKnownIntValue()) {
bool cond = condTok->values().front().intvalue;
if (cond) {
FwdAnalysis::Result result = checkRecursive(expr, bodyStart, bodyStart->link(), exprVarIds, local, true, depth);
if (result.type != Result::Type::NONE)
return result;
} else if (Token::simpleMatch(bodyStart->link(), "} else {")) {
bodyStart = bodyStart->link()->tokAt(2);
FwdAnalysis::Result result = checkRecursive(expr, bodyStart, bodyStart->link(), exprVarIds, local, true, depth);
if (result.type != Result::Type::NONE)
return result;
}
}
tok = bodyStart->link();
if (isReturnScope(tok, &mLibrary))
return Result(Result::Type::BAILOUT);
if (Token::simpleMatch(tok, "} else {"))
tok = tok->linkAt(2);
if (!tok)
return Result(Result::Type::BAILOUT);
// Is expr changed in condition?
if (!isUnchanged(conditionStart, conditionStart->link(), exprVarIds, local))
return Result(Result::Type::BAILOUT);
// Is expr changed in condition body?
if (!isUnchanged(bodyStart, bodyStart->link(), exprVarIds, local))
return Result(Result::Type::BAILOUT);
}
if (!local && Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) {
// TODO: this is a quick bailout
return Result(Result::Type::BAILOUT);
}
if (mWhat == What::Reassign &&
Token::simpleMatch(tok, ";") &&
Token::simpleMatch(tok->astParent(), ";") &&
Token::simpleMatch(tok->astParent()->astParent(), "(") &&
Token::simpleMatch(tok->astParent()->astParent()->previous(), "for (") &&
!isUnchanged(tok, tok->astParent()->astParent()->link(), exprVarIds, local))
// TODO: This is a quick bailout to avoid FP #9420, there are false negatives (TODO_ASSERT_EQUALS)
return Result(Result::Type::BAILOUT);
if (expr->isName() && Token::Match(tok, "%name% (") && tok->str().find("<") != std::string::npos && tok->str().find(expr->str()) != std::string::npos)
return Result(Result::Type::BAILOUT);
if (exprVarIds.find(tok->varId()) != exprVarIds.end()) {
const Token *parent = tok;
bool other = false;
bool same = tok->astParent() && isSameExpression(mCpp, false, expr, tok, mLibrary, true, false, nullptr);
while (!same && Token::Match(parent->astParent(), "*|.|::|[|(|%cop%")) {
parent = parent->astParent();
if (parent->str() == "(" && !parent->isCast())
break;
if (isSameExpression(mCpp, false, expr, parent, mLibrary, true, false, nullptr)) {
same = true;
if (mWhat == What::ValueFlow) {
KnownAndToken v;
v.known = mValueFlowKnown;
v.token = parent;
mValueFlow.push_back(v);
}
}
if (Token::Match(parent, ". %var%") && parent->next()->varId() && exprVarIds.find(parent->next()->varId()) == exprVarIds.end() &&
isSameExpression(mCpp, false, expr->astOperand1(), parent->astOperand1(), mLibrary, true, false, nullptr)) {
other = true;
break;
}
}
if (mWhat != What::ValueFlow && same && Token::simpleMatch(parent->astParent(), "[") && parent == parent->astParent()->astOperand2()) {
return Result(Result::Type::READ);
}
if (other)
continue;
if (Token::simpleMatch(parent->astParent(), "=") && parent == parent->astParent()->astOperand1()) {
if (!local && hasFunctionCall(parent->astParent()->astOperand2())) {
// TODO: this is a quick bailout
return Result(Result::Type::BAILOUT);
}
if (hasOperand(parent->astParent()->astOperand2(), expr)) {
if (mWhat == What::Reassign)
return Result(Result::Type::READ);
continue;
}
const auto startEnd = parent->astParent()->astOperand2()->findExpressionStartEndTokens();
for (const Token* tok2 = startEnd.first; tok2 != startEnd.second; tok2 = tok2->next()) {
if (tok2->tokType() == Token::eLambda)
return Result(Result::Type::BAILOUT);
// TODO: analyze usage in lambda
}
// ({ .. })
if (hasGccCompoundStatement(parent->astParent()->astOperand2()))
return Result(Result::Type::BAILOUT);
const bool reassign = isSameExpression(mCpp, false, expr, parent, mLibrary, false, false, nullptr);
if (reassign)
return Result(Result::Type::WRITE, parent->astParent());
return Result(Result::Type::READ);
} else if (mWhat == What::Reassign && parent->valueType() && parent->valueType()->pointer && Token::Match(parent->astParent(), "%assign%") && parent == parent->astParent()->astOperand1()) {
return Result(Result::Type::READ);
} else if (Token::Match(parent->astParent(), "%assign%") && !parent->astParent()->astParent() && parent == parent->astParent()->astOperand1()) {
if (mWhat == What::Reassign)
return Result(Result::Type::BAILOUT, parent->astParent());
if (mWhat == What::UnusedValue && (!parent->valueType() || parent->valueType()->reference != Reference::None))
return Result(Result::Type::BAILOUT, parent->astParent());
continue;
} else if (mWhat == What::UnusedValue && parent->isUnaryOp("&") && Token::Match(parent->astParent(), "[,(]")) {
// Pass variable to function the writes it
const Token *ftok = parent->astParent();
while (Token::simpleMatch(ftok, ","))
ftok = ftok->astParent();
if (ftok && Token::Match(ftok->previous(), "%name% (")) {
const std::vector<const Token *> args = getArguments(ftok);
int argnr = 0;
while (argnr < args.size() && args[argnr] != parent)
argnr++;
if (argnr < args.size()) {
const Library::Function* functionInfo = mLibrary.getFunction(ftok->astOperand1());
if (functionInfo) {
const auto it = functionInfo->argumentChecks.find(argnr + 1);
if (it != functionInfo->argumentChecks.end() && it->second.direction == Library::ArgumentChecks::Direction::DIR_OUT)
continue;
}
}
}
return Result(Result::Type::BAILOUT, parent->astParent());
} else {
// TODO: this is a quick bailout
return Result(Result::Type::BAILOUT, parent->astParent());
}
}
if (Token::Match(tok, ")|do {")) {
if (tok->str() == ")" && Token::simpleMatch(tok->link()->previous(), "switch ("))
// TODO: parse switch
return Result(Result::Type::BAILOUT);
const Result &result1 = checkRecursive(expr, tok->tokAt(2), tok->linkAt(1), exprVarIds, local, inInnerClass, depth);
if (result1.type == Result::Type::READ || result1.type == Result::Type::BAILOUT)
return result1;
if (mWhat == What::ValueFlow && result1.type == Result::Type::WRITE)
mValueFlowKnown = false;
if (mWhat == What::Reassign && result1.type == Result::Type::BREAK) {
const Token *scopeEndToken = findNextTokenFromBreak(result1.token);
if (scopeEndToken) {
const Result &result2 = checkRecursive(expr, scopeEndToken->next(), endToken, exprVarIds, local, inInnerClass, depth);
if (result2.type == Result::Type::BAILOUT)
return result2;
}
}
if (Token::simpleMatch(tok->linkAt(1), "} else {")) {
const Token *elseStart = tok->linkAt(1)->tokAt(2);
const Result &result2 = checkRecursive(expr, elseStart, elseStart->link(), exprVarIds, local, inInnerClass, depth);
if (mWhat == What::ValueFlow && result2.type == Result::Type::WRITE)
mValueFlowKnown = false;
if (result2.type == Result::Type::READ || result2.type == Result::Type::BAILOUT)
return result2;
if (result1.type == Result::Type::WRITE && result2.type == Result::Type::WRITE)
return result1;
tok = elseStart->link();
} else {
tok = tok->linkAt(1);
}
}
}
return Result(Result::Type::NONE);
}
static bool hasVolatileCastOrVar(const Token *expr)
{
bool ret = false;
visitAstNodes(expr,
[&ret](const Token *tok) {
if (Token::simpleMatch(tok, "( volatile"))
ret = true;
else if (tok->variable() && tok->variable()->isVolatile())
ret = true;
return ret ? ChildrenToVisit::none : ChildrenToVisit::op1_and_op2;
});
return ret;
}
bool FwdAnalysis::isGlobalData(const Token *expr) const
{
return ::isGlobalData(expr, mCpp);
}
std::set<nonneg int> FwdAnalysis::getExprVarIds(const Token* expr, bool* localOut, bool* unknownVarIdOut) const
{
// all variable ids in expr.
std::set<nonneg int> exprVarIds;
bool local = true;
bool unknownVarId = false;
visitAstNodes(expr,
[&](const Token *tok) {
if (tok->str() == "[" && mWhat == What::UnusedValue)
return ChildrenToVisit::op1;
if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".") {
// unknown variable
unknownVarId = true;
return ChildrenToVisit::none;
}
if (tok->varId() > 0) {
exprVarIds.insert(tok->varId());
if (!Token::simpleMatch(tok->previous(), ".")) {
const Variable *var = tok->variable();
if (var && var->isReference() && var->isLocal() && Token::Match(var->nameToken(), "%var% [=(]") && !isGlobalData(var->nameToken()->next()->astOperand2()))
return ChildrenToVisit::none;
const bool deref = tok->astParent() && (tok->astParent()->isUnaryOp("*") || (tok->astParent()->str() == "[" && tok == tok->astParent()->astOperand1()));
local &= !nonLocal(tok->variable(), deref);
}
}
return ChildrenToVisit::op1_and_op2;
});
if (localOut)
*localOut = local;
if (unknownVarIdOut)
*unknownVarIdOut = unknownVarId;
return exprVarIds;
}
FwdAnalysis::Result FwdAnalysis::check(const Token* expr, const Token* startToken, const Token* endToken)
{
// all variable ids in expr.
bool local = true;
bool unknownVarId = false;
std::set<nonneg int> exprVarIds = getExprVarIds(expr, &local, &unknownVarId);
if (unknownVarId)
return Result(FwdAnalysis::Result::Type::BAILOUT);
if (mWhat == What::Reassign && isGlobalData(expr))
local = false;
// In unused values checking we do not want to check assignments to
// global data.
if (mWhat == What::UnusedValue && isGlobalData(expr))
return Result(FwdAnalysis::Result::Type::BAILOUT);
Result result = checkRecursive(expr, startToken, endToken, exprVarIds, local, false);
// Break => continue checking in outer scope
while (mWhat!=What::ValueFlow && result.type == FwdAnalysis::Result::Type::BREAK) {
const Token *scopeEndToken = findNextTokenFromBreak(result.token);
if (!scopeEndToken)
break;
result = checkRecursive(expr, scopeEndToken->next(), endToken, exprVarIds, local, false);
}
return result;
}
bool FwdAnalysis::hasOperand(const Token *tok, const Token *lhs) const
{
if (!tok)
return false;
if (isSameExpression(mCpp, false, tok, lhs, mLibrary, false, false, nullptr))
return true;
return hasOperand(tok->astOperand1(), lhs) || hasOperand(tok->astOperand2(), lhs);
}
const Token *FwdAnalysis::reassign(const Token *expr, const Token *startToken, const Token *endToken)
{
if (hasVolatileCastOrVar(expr))
return nullptr;
mWhat = What::Reassign;
Result result = check(expr, startToken, endToken);
return result.type == FwdAnalysis::Result::Type::WRITE ? result.token : nullptr;
}
bool FwdAnalysis::unusedValue(const Token *expr, const Token *startToken, const Token *endToken)
{
if (isEscapedAlias(expr))
return false;
if (hasVolatileCastOrVar(expr))
return false;
mWhat = What::UnusedValue;
Result result = check(expr, startToken, endToken);
return (result.type == FwdAnalysis::Result::Type::NONE || result.type == FwdAnalysis::Result::Type::RETURN) && !possiblyAliased(expr, startToken);
}
bool FwdAnalysis::possiblyAliased(const Token *expr, const Token *startToken) const
{
if (expr->isUnaryOp("*"))
return true;
const bool macro = false;
const bool pure = false;
const bool followVar = false;
for (const Token *tok = startToken; tok; tok = tok->previous()) {
if (tok->str() == "{" && tok->scope()->type == Scope::eFunction && !(tok->astParent() && tok->astParent()->str() == ","))
break;
if (Token::Match(tok, "%name% (") && !Token::Match(tok, "if|while|for")) {
// Is argument passed by reference?
const std::vector<const Token*> args = getArguments(tok);
for (int argnr = 0; argnr < args.size(); ++argnr) {
if (!Token::Match(args[argnr], "%name%|.|::"))
continue;
if (tok->function() && tok->function()->getArgumentVar(argnr) && !tok->function()->getArgumentVar(argnr)->isReference() && !tok->function()->isConst())
continue;
for (const Token *subexpr = expr; subexpr; subexpr = subexpr->astOperand1()) {
if (isSameExpression(mCpp, macro, subexpr, args[argnr], mLibrary, pure, followVar)) {
const Scope* scope = expr->scope(); // if there is no other variable, assume no aliasing
if (scope->varlist.size() > 1)
return true;
}
}
}
continue;
}
const Token *addrOf = nullptr;
if (Token::Match(tok, "& %name% ="))
addrOf = tok->tokAt(2)->astOperand2();
else if (tok->isUnaryOp("&"))
addrOf = tok->astOperand1();
else if (Token::simpleMatch(tok, "std :: ref ("))
addrOf = tok->tokAt(3)->astOperand2();
else
continue;
for (const Token *subexpr = expr; subexpr; subexpr = subexpr->astOperand1()) {
if (isSameExpression(mCpp, macro, subexpr, addrOf, mLibrary, pure, followVar))
return true;
}
}
return false;
}
bool FwdAnalysis::isEscapedAlias(const Token* expr)
{
for (const Token *subexpr = expr; subexpr; subexpr = subexpr->astOperand1()) {
for (const ValueFlow::Value &val : subexpr->values()) {
if (!val.isLocalLifetimeValue())
continue;
const Variable* var = val.tokvalue->variable();
if (!var)
continue;
if (!var->isLocal())
return true;
if (var->isArgument())
return true;
}
}
return false;
}
bool isSizeOfEtc(const Token *tok)
{
return Token::Match(tok, "sizeof|typeof|offsetof|decltype|__typeof__ (");
}