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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2021 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 "library.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "valueflow.h"
#include <algorithm>
#include <deque>
#include <functional>
#include <iterator>
#include <list>
#include <set>
#include <stack>
#include <utility>
template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
void visitAstNodesGeneric(T *ast, std::function<ChildrenToVisit(T *)> visitor)
{
std::stack<T *> tokens;
tokens.push(ast);
while (!tokens.empty()) {
T *tok = tokens.top();
tokens.pop();
if (!tok)
continue;
ChildrenToVisit c = visitor(tok);
if (c == ChildrenToVisit::done)
break;
if (c == ChildrenToVisit::op1 || c == ChildrenToVisit::op1_and_op2)
tokens.push(tok->astOperand1());
if (c == ChildrenToVisit::op2 || c == ChildrenToVisit::op1_and_op2)
tokens.push(tok->astOperand2());
}
}
void visitAstNodes(const Token *ast, std::function<ChildrenToVisit(const Token *)> visitor)
{
visitAstNodesGeneric(ast, std::move(visitor));
}
void visitAstNodes(Token *ast, std::function<ChildrenToVisit(Token *)> visitor)
{
visitAstNodesGeneric(ast, std::move(visitor));
}
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 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 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 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;
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;
}
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;
}
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);
}
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;
*varid = initExpr->astOperand1()->varId();
*knownInitValue = initExpr->astOperand2()->hasKnownIntValue();
*initValue = (*knownInitValue) ? initExpr->astOperand2()->getKnownIntValue() : 0;
*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)
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* nestedIn = fScope->functionOf;
if (nestedIn && nestedIn->function)
nestedIn = nestedIn->function->token->scope();
while (nestedIn && nestedIn != expr->function()->nestedIn) {
nestedIn = nestedIn->nestedIn;
}
return nestedIn == expr->function()->nestedIn;
} 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;
}
/// 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;
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) {
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;
});
}
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 bool isSameConstantValue(bool macro, const Token * const tok1, const Token * const tok2)