/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2019 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 .
*/
//---------------------------------------------------------------------------
#include "astutils.h"
#include "library.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "valueflow.h"
#include
#include
#include
void visitAstNodes(const Token *ast, std::function visitor)
{
std::stack tokens;
tokens.push(ast);
while (!tokens.empty()) {
const Token *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());
}
}
static void astFlattenRecursive(const Token *tok, std::vector *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 astFlatten(const Token* tok, const char* op)
{
std::vector result;
astFlattenRecursive(tok, &result, op);
return result;
}
bool astHasToken(const Token* root, const Token * tok)
{
if (!root)
return false;
if (root == tok)
return true;
return astHasToken(root->astOperand1(), tok) || astHasToken(root->astOperand2(), 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 astIsIntegral(const Token *tok, bool unknown)
{
const ValueType *vt = tok ? tok->valueType() : nullptr;
if (!vt)
return unknown;
return vt->isIntegral() && vt->pointer == 0U;
}
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 && tok->valueType()->type != ValueType::Type::ITERATOR;
}
std::string astCanonicalType(const Token *expr)
{
if (!expr)
return "";
if (expr->variable()) {
const Variable *var = expr->variable();
std::string ret;
for (const Token *type = var->typeStartToken(); Token::Match(type,"%name%|::") && type != var->nameToken(); type = type->next()) {
if (!Token::Match(type, "const|static"))
ret += type->str();
}
return ret;
}
// TODO: handle expressions
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")) {
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)
{
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::Match(tok->previous(), ">|%name% (")) {
const Token* ftok = nullptr;
if (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 (library) {
std::string returnType = library->returnValueType(ftok);
return !returnType.empty() && returnType.back() != '&';
} else {
return false;
}
}
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;
}
const Token * nextAfterAstRightmostLeaf(const Token * tok)
{
const Token * rightmostLeaf = tok;
if (!rightmostLeaf || !rightmostLeaf->astOperand1())
return nullptr;
do {
if (rightmostLeaf->astOperand2())
rightmostLeaf = rightmostLeaf->astOperand2();
else
rightmostLeaf = rightmostLeaf->astOperand1();
} while (rightmostLeaf->astOperand1());
while (Token::Match(rightmostLeaf->next(), "]|)") && !hasToken(rightmostLeaf->next()->link(), rightmostLeaf->next(), tok))
rightmostLeaf = rightmostLeaf->next();
if (rightmostLeaf->str() == "{" && rightmostLeaf->link())
rightmostLeaf = rightmostLeaf->link();
return rightmostLeaf->next();
}
const Token* astParentSkipParens(const Token* tok)
{
return astParentSkipParens(const_cast(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;
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 (tok == parent->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;
}
static const Token * getVariableInitExpression(const Variable * var)
{
if (!var || !var->declEndToken())
return nullptr;
if (Token::Match(var->declEndToken(), "; %varid% =", var->declarationId()))
return var->declEndToken()->tokAt(2)->astOperand2();
return var->declEndToken()->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 false;
return tok1->index() < tok2->index();
}
bool isAliasOf(const Token *tok, nonneg int varid)
{
if (tok->varId() == varid)
return false;
if (tok->varId() == 0)
return false;
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isLocalLifetimeValue())
continue;
if (val.isInconclusive())
continue;
if (val.tokvalue->varId() == varid)
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, nonneg int depth)
{
if (!expr)
return false;
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 *nestedIn = expr->scope()->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 (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(), depth);
return exprDependsOnThis(expr->astOperand1(), depth) || exprDependsOnThis(expr->astOperand2(), depth);
}
/// 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;
// Bailout. If variable value depends on value of "this".
if (exprDependsOnThis(varTok))
return tok;
// Skip array access
if (Token::simpleMatch(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;
// Start at beginning of initialization
const Token * startToken = varTok;
while (Token::Match(startToken, "%op%|.|(|{") && startToken->astOperand1())
startToken = startToken->astOperand1();
// Skip if the variable its referring to is modified
for (const Token * tok2 = startToken; tok2 != endToken; tok2 = tok2->next()) {
if (Token::simpleMatch(tok2, ";"))
break;
if (tok2->astParent() && tok2->isUnaryOp("*"))
return tok;
if (tok2->tokType() == Token::eIncDecOp ||
tok2->isAssignmentOp() ||
Token::Match(tok2, "%name% .|[|++|--|%assign%")) {
return tok;
}
if (const Variable * var2 = tok2->variable()) {
if (!var2->scope())
return tok;
const Token * endToken2 = var2->scope() != tok->scope() ? var2->scope()->bodyEnd : endToken;
if (!var2->isLocal() && !var2->isConst() && !var2->isArgument())
return tok;
if (var2->isStatic() && !var2->isConst())
return tok;
if (!var2->isConst() && (!precedes(tok2, endToken2) || isVariableChanged(tok2, endToken2, tok2->varId(), false, nullptr, cpp)))
return tok;
if (precedes(tok2, endToken2) && isAliased(tok2, endToken2, tok2->varId()))
return tok;
// Recognized as a variable but the declaration is unknown
} else if (tok2->varId() > 0) {
return tok;
} else if (tok2->tokType() == Token::eName && !Token::Match(tok2, "sizeof|decltype|typeof") && !tok2->function()) {
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);
}
static void findTokenValue(const Token* const tok, std::function pred, std::function f)
{
auto x = std::find_if(tok->values().begin(), tok->values().end(), pred);
if (x != tok->values().end())
f(*x);
}
bool isEqualKnownValue(const Token * const tok1, const Token * const tok2)
{
bool result = false;
findTokenValue(tok1, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v1) {
findTokenValue(tok2, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v2) {
result = v1.equalValue(v2);
});
});
return result;
}
bool isDifferentKnownValues(const Token * const tok1, const Token * const tok2)
{
bool result = false;
findTokenValue(tok1, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v1) {
findTokenValue(tok2, std::mem_fn(&ValueFlow::Value::isKnown), [&](const ValueFlow::Value& v2) {
result = !v1.equalValue(v2);
});
});
return result;
}
static 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);
}
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);
}
if (tok1->str() != tok2->str() && isDifferentKnownValues(tok1, tok2))
return false;
if (isSameConstantValue(macro, tok1, tok2))
return true;
// Follow variable
if (followVar && tok1->str() != tok2->str() && (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);
}
}
if (tok1->varId() != tok2->varId() || tok1->str() != tok2->str() || 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);
}
return false;
}
if (macro && (tok1->isExpandedMacro() || tok2->isExpandedMacro() || tok1->isTemplateArg() || tok2->isTemplateArg()))
return false;
if (tok1->isComplex() != tok2->isComplex())
return false;
if (tok1->isLong() != tok2->isLong())
return false;
if (tok1->isUnsigned() != tok2->isUnsigned())
return false;
if (tok1->isSigned() != tok2->isSigned())
return false;
if (pure && tok1->isName() && tok1->next()->str() == "(" && tok1->str() != "sizeof") {
if (!tok1->function()) {
if (Token::simpleMatch(tok1->previous(), ".")) {
const Token *lhs = tok1->previous();
while (Token::Match(lhs, "(|.|["))
lhs = lhs->astOperand1();
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())
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() &&
t1->isLong() == t2->isLong() &&
t1->isUnsigned() == t2->isUnsigned() &&
t1->isSigned() == t2->isSigned() &&
(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 (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);
}
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") &&
cond1->astOperand1()->astOperand1()->varId() == cond2->astOperand1()->astOperand1()->astOperand1()->varId()) {
return !isZeroBoundCond(cond2);
}
if (Library::isContainerYield(cond2, Library::Container::Yield::EMPTY, "empty") &&
Library::isContainerYield(cond1->astOperand1(), Library::Container::Yield::SIZE, "size") &&
cond2->astOperand1()->astOperand1()->varId() == cond1->astOperand1()->astOperand1()->astOperand1()->varId()) {
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("-"))
return isSameExpression(cpp, true, tok1->astOperand1(), tok2, library, pure, followVar, errors);
if (tok2->isUnaryOp("-"))
return isSameExpression(cpp, true, tok2->astOperand1(), tok1, library, pure, followVar, errors);
return false;
}
bool isConstExpression(const Token *tok, const Library& library, bool pure, bool cpp)
{
if (!tok)
return true;
if (tok->isName() && tok->next()->str() == "(") {
if (!tok->function() && !Token::Match(tok->previous(), ".|::") && !library.isFunctionConst(tok->str(), pure))
return false;
else if (tok->function() && !tok->function()->isConst())
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)
{
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() || var->isPointer() || 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.tokenDef);
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* setOfVars[] = {&scope->varlist, fun ? &fun->argumentList : nullptr};
for (const std::list* 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)
{
if (functionsScope)
return Token::simpleMatch(tok, "throw");
else
return Token::Match(tok, "return|throw");
}
static bool isEscapedOrJump(const Token* tok, bool functionsScope)
{
if (functionsScope)
return Token::simpleMatch(tok, "throw");
else
return Token::Match(tok, "return|goto|throw|continue|break");
}
bool isReturnScope(const Token * const endToken, const Library * library, 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, functionScope) && isReturnScope(prev->link()->tokAt(-2), library, functionScope);
if (Token::simpleMatch(prev->link()->previous(), ") {") &&
Token::simpleMatch(prev->link()->linkAt(-1)->previous(), "switch (") &&
!Token::findsimplematch(prev->link(), "break", prev)) {
return true;
}
if (isEscaped(prev->link()->astTop(), functionScope))
return true;
if (Token::Match(prev->link()->previous(), "[;{}] {"))
return isReturnScope(prev, library, functionScope);
} else if (Token::simpleMatch(prev, ";")) {
if (Token::simpleMatch(prev->previous(), ") ;") && Token::Match(prev->linkAt(-1)->tokAt(-2), "[;{}] %name% (")) {
const Token * ftok = prev->linkAt(-1)->previous();
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;
}
if (Token::simpleMatch(prev->previous(), ") ;") && prev->previous()->link() &&
isEscaped(prev->previous()->link()->astTop(), functionScope))
return true;
if (isEscaped(prev->previous()->astTop(), functionScope))
return true;
// return/goto statement
prev = prev->previous();
while (prev && !Token::Match(prev, ";|{|}") && !isEscapedOrJump(prev, functionScope))
prev = prev->previous();
return prev && prev->isName();
}
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;
}
const Token * getTokenArgumentFunction(const Token * tok, int& argn)
{
argn = -1;
{
const Token *parent = tok->astParent();
if (parent && parent->isUnaryOp("&"))
parent = parent->astParent();
while (parent && parent->isCast())
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;
}
// goto start of function call and get argn
argn = 0;
while (tok && !Token::simpleMatch(tok, ";") && !isScopeBracket(tok)) {
if (tok->str() == ",")
++argn;
else if (Token::Match(tok, ")|}"))
tok = tok->link();
else if (Token::Match(tok->previous(), "%name% (|{"))
break;
else if (Token::Match(tok->previous(), "> (|{") && tok->previous()->link())
break;
tok = tok->previous();
}
if (!Token::Match(tok, "{|("))
return nullptr;
tok = tok->previous();
if (tok && tok->link() && tok->str() == ">")
tok = tok->link()->previous();
if (!Token::Match(tok, "%name% [({<]"))
return nullptr;
return tok;
}
bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Settings *settings, bool *inconclusive)
{
if (!tok)
return false;
const Token * const tok1 = tok;
// address of variable
const bool addressOf = tok->astParent() && tok->astParent()->isUnaryOp("&");
int argnr;
tok = getTokenArgumentFunction(tok, argnr);
if (!tok)
return false; // not a function => variable not changed
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% [,)}]"));
// Constructor call
if (tok->variable() && tok->variable()->nameToken() == tok) {
// Find constructor..
const int argCount = numberOfArguments(tok);
const Scope *typeScope = tok->variable()->typeScope();
if (typeScope) {
for (const Function &function : typeScope->functionList) {
if (!function.isConstructor() || function.argCount() < argCount)
continue;
const Variable *arg = function.getArgumentVar(argnr);
if (arg && arg->isReference() && !arg->isConst())
return true;
}
return false;
}
if (inconclusive)
*inconclusive = true;
return false;
}
if (!tok->function()) {
// Check if direction (in, out, inout) is specified in the library configuration and use that
if (!addressOf && settings) {
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) {
// With out or inout the direction of the content is specified, not a pointer itself, so ignore pointers for now
const ValueType * const valueType = tok1->valueType();
if (valueType && valueType->pointer == indirect) {
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 (!addressOf && settings && settings->library.isnullargbad(tok, 1+argnr))
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;
}
const Variable *arg = tok->function()->getArgumentVar(argnr);
if (addressOf || (indirect > 0 && arg && arg->isPointer())) {
if (!(arg && arg->isConst()))
return true;
// If const is applied to the pointer, then the value can still be modified
if (arg && Token::simpleMatch(arg->typeEndToken(), "* const"))
return true;
}
return arg && !arg->isConst() && arg->isReference();
}
bool isVariableChanged(const Token *tok, int indirect, const Settings *settings, bool cpp, int depth)
{
if (!tok)
return false;
const Token *tok2 = tok;
while (Token::simpleMatch(tok2->astParent(), "*") || (Token::simpleMatch(tok2->astParent(), ".") && !Token::simpleMatch(tok2->astParent()->astParent(), "(")) ||
(Token::simpleMatch(tok2->astParent(), "[") && tok2 == tok2->astParent()->astOperand1()))
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 (isLikelyStreamRead(cpp, tok->previous()))
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();
bool isConst = var && var->isConst();
if (!isConst && var) {
const ValueType * valueType = var->valueType();
isConst = (valueType && valueType->pointer == 1 && valueType->constness == 1);
}
const Token *ftok = tok->tokAt(2);
const Function * fun = ftok->function();
if (!isConst && (!fun || !fun->isConst()))
return true;
else
return false;
}
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;
if (Token::simpleMatch(tok2->astParent(), ":") && tok2->astParent()->astParent() && Token::simpleMatch(tok2->astParent()->astParent()->previous(), "for (")) {
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;
}
return false;
}
bool isVariableChanged(const Token *start, const Token *end, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
return findVariableChanged(start, end, 0, varid, globalvar, settings, cpp, depth) != nullptr;
}
Token* findVariableChanged(Token *start, const Token *end, int indirect, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
if (!precedes(start, end))
return nullptr;
if (depth < 0)
return start;
for (Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() != varid) {
if (globalvar && Token::Match(tok, "%name% ("))
// TODO: Is global variable really changed by function call?
return tok;
continue;
}
if (isVariableChanged(tok, indirect, settings, cpp, depth))
return tok;
}
return nullptr;
}
const Token* findVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
return findVariableChanged(const_cast(start), end, indirect, varid, 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 isVariableChanged(start->next(), var->scope()->bodyEnd, var->declarationId(), var->isGlobal(), settings, cpp, depth);
}
bool isVariablesChanged(const Token* start,
const Token* end,
int indirect,
std::vector vars,
const Settings* settings,
bool cpp)
{
std::set 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;
}
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 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 *startTok = tok->astOperand2();
if (!startTok && tok->next() != tok->link())
startTok = tok->astOperand1();
return astFlatten(startTok, ",");
}
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;
}
const Token *findLambdaEndToken(const Token *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;
}
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() && tok->astOperand1()->str().find("_cast") != std::string::npos;
}
bool isConstVarExpression(const Token *tok, const char* skipMatch)
{
if (!tok)
return false;
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 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 const Variable *getLHSVariableRecursive(const Token *tok)
{
if (!tok)
return nullptr;
if (Token::Match(tok, "*|&|&&|[")) {
const Variable *var = getLHSVariableRecursive(tok->astOperand1());
if (var || Token::simpleMatch(tok, "["))
return var;
return getLHSVariableRecursive(tok->astOperand2());
}
if (Token::Match(tok->previous(), "this . %var%"))
return tok->next()->variable();
return tok->variable();
}
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();
return getLHSVariableRecursive(tok->astOperand1());
}
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 &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()));
}
struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set &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 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;
Scope::ScopeType scopeType = tok->scope()->type;
if (scopeType == Scope::eWhile || scopeType == Scope::eFor || scopeType == Scope::eDo) {
// 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 && 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()) {
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;
}
// ({ .. })
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());
continue;
} 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 (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);
}
bool FwdAnalysis::isGlobalData(const Token *expr) const
{
bool globalData = false;
visitAstNodes(expr,
[&](const Token *tok) {
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 (mCpp && 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;
}
std::set FwdAnalysis::getExprVarIds(const Token* expr, bool* localOut, bool* unknownVarIdOut) const
{
// all variable ids in expr.
std::set exprVarIds;
bool local = true;
bool unknownVarId = false;
visitAstNodes(expr,
[&](const Token *tok) {
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 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 Scope *s = result.token->scope();
while (s->type == Scope::eIf)
s = s->nestedIn;
if (s->type != Scope::eSwitch && s->type != Scope::eWhile && s->type != Scope::eFor)
break;
result = checkRecursive(expr, s->bodyEnd->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)
{
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;
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);
}
std::vector FwdAnalysis::valueFlow(const Token *expr, const Token *startToken, const Token *endToken)
{
mWhat = What::ValueFlow;
mValueFlowKnown = true;
check(expr, startToken, endToken);
return mValueFlow;
}
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)
break;
if (Token::Match(tok, "%name% (") && !Token::Match(tok, "if|while|for")) {
// Is argument passed by reference?
const std::vector 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))
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;
}