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valueflow.cpp
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1084 lines (968 loc) · 43.7 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2014 Daniel Marjamäki and Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "valueflow.h"
#include "errorlogger.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenlist.h"
//#include <iostream>
#include <stack>
static void execute(const Token *expr,
std::map<unsigned int, MathLib::bigint> * const programMemory,
MathLib::bigint *result,
bool *error);
//static void printvalues(const Token *tok)
//{
// if (tok->values.empty())
// std::cout << "empty";
// for (std::list<ValueFlow::Value>::const_iterator it = tok->values.begin(); it != tok->values.end(); ++it)
// std::cout << " " << (it->intvalue);
// std::cout << std::endl;
//}
static void bailout(TokenList *tokenlist, ErrorLogger *errorLogger, const Token *tok, const std::string &what)
{
std::list<ErrorLogger::ErrorMessage::FileLocation> callstack;
callstack.push_back(ErrorLogger::ErrorMessage::FileLocation(tok,tokenlist));
ErrorLogger::ErrorMessage errmsg(callstack, Severity::debug, "ValueFlow bailout: " + what, "valueFlowBailout", false);
errorLogger->reportErr(errmsg);
}
static bool bailoutFunctionPar(const Token *tok, const ValueFlow::Value &value, const Settings *settings, bool *inconclusive)
{
if (!tok)
return false;
// address of variable
const bool addressOf = tok && Token::simpleMatch(tok->previous(), "&");
// passing variable to subfunction?
if (Token::Match(tok->tokAt(-2), ") & %var% [,)]") && Token::Match(tok->linkAt(-2)->previous(), "[,(] ("))
;
else if (Token::Match(tok->tokAt(addressOf?-2:-1), "[(,] &| %var% [,)]"))
;
else
return false;
// reinterpret_cast etc..
if (Token::Match(tok->tokAt(-3), "> ( & %var% ) [,)]") &&
tok->linkAt(-3) &&
Token::Match(tok->linkAt(-3)->tokAt(-2), "[,(] %type% <"))
tok = tok->linkAt(-3);
// goto start of function call and get argnr
unsigned int argnr = 0;
while (tok && tok->str() != "(") {
if (tok->str() == ",")
++argnr;
else if (tok->str() == ")")
tok = tok->link();
tok = tok->previous();
}
tok = tok ? tok->previous() : nullptr;
if (!Token::Match(tok,"%var% ("))
return false; // not a function => do not bailout
if (!tok->function()) {
// if value is 0 and the library says 0 is invalid => do not bailout
if (value.intvalue==0 && settings->library.isnullargbad(tok->str(), 1+argnr))
return false;
// addressOf => inconclusive
if (!addressOf) {
*inconclusive = true;
return false;
}
return true;
}
const Variable *arg = tok->function()->getArgumentVar(argnr);
if (addressOf && !(arg && arg->isConst()))
return true;
return arg && !arg->isConst() && arg->isReference();
}
/**
* Is condition always false when variable has given value?
* \param condition top ast token in condition
* \param varid variable id for variable
* \param value value of variable
*/
static bool conditionIsFalse(const Token *condition, unsigned int varid, const ValueFlow::Value &value)
{
if (!condition)
return false;
if (condition->str() == "&&") {
bool result1 = conditionIsFalse(condition->astOperand1(), varid, value);
bool result2 = result1 ? true : conditionIsFalse(condition->astOperand2(), varid, value);
return result2;
}
std::map<unsigned int, MathLib::bigint> programMemory;
programMemory[varid] = value.intvalue;
MathLib::bigint result = 0;
bool error = false;
execute(condition, &programMemory, &result, &error);
return !error && result == 0;
}
/**
* Should value be skipped because it's hidden inside && || or ?: expression.
* Example: ((x!=NULL) && (*x == 123))
* If 'valuetok' points at the x in '(*x == 123)'. Then the '&&' will be returned.
* @param valuetok original variable token
* @return NULL=>don't skip, non-NULL=>The operator token that cause the skip. For instance the '&&'.
* */
static const Token * skipValueInConditionalExpression(const Token * const valuetok)
{
// Walk up the ast
const Token *prev = valuetok;
for (const Token *tok = valuetok->astParent(); tok; tok = tok->astParent()) {
const bool prevIsLhs = (prev == tok->astOperand1());
prev = tok;
if (prevIsLhs || !Token::Match(tok, "%oror%|&&|?|:"))
continue;
// Is variable protected in LHS..
std::stack<const Token *> tokens;
tokens.push(tok->astOperand1());
while (!tokens.empty()) {
const Token * const tok2 = tokens.top();
tokens.pop();
if (!tok2)
continue;
if (tok2 != valuetok && tok2->str() == valuetok->str())
return tok;
tokens.push(tok2->astOperand2());
tokens.push(tok2->astOperand1());
}
}
return nullptr;
}
static bool bailoutSelfAssignment(const Token * const tok)
{
const Token *parent = tok;
while (parent) {
const Token *op = parent;
parent = parent->astParent();
// Assignment where lhs variable exists in rhs => return true
if (parent != nullptr &&
parent->astOperand2() == op &&
parent->astOperand1() != nullptr &&
parent->str() == "=") {
for (const Token *lhs = parent->astOperand1(); lhs; lhs = lhs->astOperand1()) {
if (lhs->varId() == tok->varId())
return true;
if (lhs->astOperand2() && lhs->astOperand2()->varId() == tok->varId())
return true;
}
}
}
return false;
}
static bool isVariableChanged(const Token *start, const Token *end, const unsigned int varid)
{
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() == varid) {
if (Token::Match(tok, "%var% ="))
return true;
const Token *parent = tok->astParent();
while (parent && parent->str() == ".")
parent = parent->astParent();
if (parent && parent->type() == Token::eIncDecOp)
return true;
}
}
return false;
}
/** set ValueFlow value and perform calculations if possible */
static void setTokenValue(Token* tok, const ValueFlow::Value &value)
{
// if value already exists, don't add it again
std::list<ValueFlow::Value>::iterator it;
for (it = tok->values.begin(); it != tok->values.end(); ++it) {
if (it->intvalue == value.intvalue) {
if (it->inconclusive && !value.inconclusive) {
*it = value;
break;
}
return;
}
}
if (it == tok->values.end()) {
tok->values.push_back(value);
it = tok->values.end();
--it;
}
Token *parent = const_cast<Token*>(tok->astParent());
// Cast..
if (parent && parent->str() == "(" && tok == parent->link()->next()) {
setTokenValue(parent,value);
}
// Calculations..
else if (parent && parent->isArithmeticalOp() && parent->astOperand1() && parent->astOperand2()) {
std::list<ValueFlow::Value>::const_iterator value1, value2;
for (value1 = parent->astOperand1()->values.begin(); value1 != parent->astOperand1()->values.end(); ++value1) {
for (value2 = parent->astOperand2()->values.begin(); value2 != parent->astOperand2()->values.end(); ++value2) {
if (value1->varId == 0U || value2->varId == 0U ||
(value1->varId == value2->varId && value1->varvalue == value2->varvalue)) {
ValueFlow::Value result(0);
result.condition = value1->condition ? value1->condition : value2->condition;
result.inconclusive = value1->inconclusive | value2->inconclusive;
result.varId = (value1->varId != 0U) ? value1->varId : value2->varId;
result.varvalue = (result.varId == value1->varId) ? value1->intvalue : value2->intvalue;
switch (parent->str()[0]) {
case '+':
result.intvalue = value1->intvalue + value2->intvalue;
setTokenValue(parent, result);
break;
case '-':
result.intvalue = value1->intvalue - value2->intvalue;
setTokenValue(parent, result);
break;
case '*':
result.intvalue = value1->intvalue * value2->intvalue;
setTokenValue(parent, result);
break;
case '/':
if (value2->intvalue == 0)
break;
result.intvalue = value1->intvalue / value2->intvalue;
setTokenValue(parent, result);
break;
case '%':
if (value2->intvalue == 0)
break;
result.intvalue = value1->intvalue % value2->intvalue;
setTokenValue(parent, result);
break;
}
}
}
}
}
}
static void valueFlowNumber(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->isNumber() && MathLib::isInt(tok->str()))
setTokenValue(tok, ValueFlow::Value(MathLib::toLongNumber(tok->str())));
}
}
static void valueFlowBitAnd(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->str() != "&")
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
MathLib::bigint number;
if (MathLib::isInt(tok->astOperand1()->str()))
number = MathLib::toLongNumber(tok->astOperand1()->str());
else if (MathLib::isInt(tok->astOperand2()->str()))
number = MathLib::toLongNumber(tok->astOperand2()->str());
else
continue;
int bit = 0;
while (bit <= 60 && ((1LL<<bit) < number))
++bit;
if ((1LL<<bit) == number) {
setTokenValue(tok, ValueFlow::Value(0));
setTokenValue(tok, ValueFlow::Value(number));
}
}
}
static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
unsigned int varid=0;
MathLib::bigint num=0;
const Variable *var=0;
if (tok->isComparisonOp() && tok->astOperand1() && tok->astOperand2()) {
if (tok->astOperand1()->isName() && tok->astOperand2()->isNumber()) {
varid = tok->astOperand1()->varId();
var = tok->astOperand1()->variable();
num = MathLib::toLongNumber(tok->astOperand2()->str());
} else if (tok->astOperand1()->isNumber() && tok->astOperand2()->isName()) {
varid = tok->astOperand2()->varId();
var = tok->astOperand2()->variable();
num = MathLib::toLongNumber(tok->astOperand1()->str());
} else {
continue;
}
} else if (Token::Match(tok->previous(), "if|while ( %var% %oror%|&&|)") ||
Token::Match(tok, "%oror%|&& %var% %oror%|&&|)")) {
varid = tok->next()->varId();
var = tok->next()->variable();
num = 0;
} else if (tok->str() == "!" && tok->astOperand1() && tok->astOperand1()->isName()) {
varid = tok->astOperand1()->varId();
var = tok->astOperand1()->variable();
num = 0;
} else {
continue;
}
if (varid == 0U || !var)
continue;
// bailout: global non-const variables
if (!(var->isLocal() || var->isArgument()) && !var->isConst()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "global variable " + var->nameToken()->str());
continue;
}
// bailout: for/while-condition, variable is changed in while loop
for (const Token *tok2 = tok; tok2; tok2 = tok2->astParent()) {
if (tok2->astParent() || tok2->str() != "(" || !Token::simpleMatch(tok2->link(), ") {"))
continue;
if (Token::Match(tok2->previous(), "for|while (")) {
const Token * const start = tok2->link()->next();
const Token * const end = start->link();
if (isVariableChanged(start,end,varid)) {
varid = 0U;
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->nameToken()->str() + " used in loop");
}
}
// if,macro => bailout
else if (Token::simpleMatch(tok2->previous(), "if (") && tok2->previous()->isExpandedMacro()) {
varid = 0U;
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->nameToken()->str() + ", condition is defined in macro");
}
}
if (varid == 0U)
continue;
// extra logic for unsigned variables 'i>=1' => possible value can also be 0
ValueFlow::Value val(tok, num);
val.varId = varid;
ValueFlow::Value val2;
if (num==1U && Token::Match(tok,"<=|>=")) {
bool isunsigned = false;
for (const Token* type = var->typeStartToken(); type && type->varId() == 0U; type = type->next())
isunsigned |= type->isUnsigned();
if (isunsigned) {
val2 = ValueFlow::Value(tok,0);
val2.varId = varid;
}
}
if (Token::Match(tok,"<|>")) {
if (num!=0)
continue;
bool isunsigned = false;
for (const Token* type = var->typeStartToken(); type && type->varId() == 0U; type = type->next())
isunsigned |= type->isUnsigned();
if (!isunsigned)
continue;
}
for (Token *tok2 = tok->previous(); ; tok2 = tok2->previous()) {
if (!tok2) {
if (settings->debugwarnings) {
std::list<ErrorLogger::ErrorMessage::FileLocation> callstack;
callstack.push_back(ErrorLogger::ErrorMessage::FileLocation(tok,tokenlist));
ErrorLogger::ErrorMessage errmsg(callstack, Severity::debug, "iterated too far", "debugValueFlowBeforeCondition", false);
errorLogger->reportErr(errmsg);
}
break;
}
if (tok2->varId() == varid) {
// bailout: assignment
if (Token::Match(tok2->previous(), "!!* %var% =")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str());
break;
}
// increment/decrement
if (Token::Match(tok2->previous(), "[;{}] %var% ++|-- ;"))
val.intvalue += (tok2->strAt(1)=="++") ? -1 : 1;
else if (Token::Match(tok2->tokAt(-2), "[;{}] ++|-- %var% ;"))
val.intvalue += (tok2->strAt(-1)=="++") ? -1 : 1;
else if (Token::Match(tok2->previous(), "++|-- %var%") || Token::Match(tok2, "%var% ++|--")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "increment/decrement of " + tok2->str());
break;
}
// bailout: variable is used in rhs in assignment to itself
if (bailoutSelfAssignment(tok2)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + tok2->str() + " is used in rhs in assignment to itself");
break;
}
if (Token::Match(tok2->previous(), "sizeof|.")) {
const Token *prev = tok2->previous();
while (Token::Match(prev,"%var%|.") && prev->str() != "sizeof")
prev = prev->previous();
if (prev && prev->str() == "sizeof")
continue;
}
// assigned by subfunction?
bool inconclusive = false;
if (bailoutFunctionPar(tok2,val2.condition ? val2 : val, settings, &inconclusive)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction");
break;
}
val.inconclusive |= inconclusive;
val2.inconclusive |= inconclusive;
// skip if variable is conditionally used in ?: expression
if (const Token *parent = skipValueInConditionalExpression(tok2)) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok2,
"no simplification of " + tok2->str() + " within " + (Token::Match(parent,"[?:]") ? "?:" : parent->str()) + " expression");
continue;
}
setTokenValue(tok2, val);
if (val2.condition)
setTokenValue(tok2,val2);
if (var && tok2 == var->nameToken())
break;
}
// skip sizeof..
if (tok2->str() == ")" && Token::Match(tok2->link()->previous(), "typeof|sizeof ("))
tok2 = tok2->link();
// goto label
if (Token::Match(tok2, "[;{}] %var% :")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2->next(), "variable " + var->nameToken()->str() + " stopping on goto label");
break;
}
if (tok2->str() == "}") {
if (Token::findmatch(tok2->link(), "%varid%", tok2, varid)) {
if (settings->debugwarnings) {
std::string errmsg = "variable ";
if (var)
errmsg += var->nameToken()->str() + " ";
errmsg += "stopping on }";
bailout(tokenlist, errorLogger, tok2, errmsg);
}
break;
} else {
tok2 = tok2->link();
}
} else if (tok2->str() == "{") {
// if variable is assigned in loop don't look before the loop
if (tok2->previous() &&
(Token::simpleMatch(tok2->previous(), "do") ||
(tok2->strAt(-1) == ")" && Token::Match(tok2->linkAt(-1)->previous(), "for|while (")))) {
const Token *start = tok2;
const Token *end = start->link();
if (isVariableChanged(start,end,varid)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " is assigned in loop. so valueflow analysis bailout when start of loop is reached.");
break;
}
}
// Global variable : stop when leaving the function scope
if (!var->isLocal()) {
if (!Token::Match(tok2->previous(), ")|else|do {"))
break;
if (Token::simpleMatch(tok2->previous(), ") {") &&
!Token::Match(tok2->linkAt(-1)->previous(), "if|for|while ("))
break;
}
} else if (tok2->str() == ";") {
const Token *parent = tok2->previous();
while (parent && !Token::Match(parent, "return|break|continue|goto"))
parent = parent->astParent();
// reaching a break/continue/return
if (parent) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " stopping on " + parent->str());
break;
}
}
}
}
}
static void valueFlowAfterAssign(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
// Assignment
if ((tok->str() != "=") || (tok->astParent()))
continue;
// Lhs should be a variable
if (!tok->astOperand1() || !tok->astOperand1()->isName())
continue;
const unsigned int varid = tok->astOperand1()->varId();
if (varid == 0U)
continue;
const Variable *var = tok->astOperand1()->variable();
if (!var || !var->isLocal())
continue;
const Token * endToken = 0;
for (const Token *tok2 = var->typeStartToken(); tok2; tok2 = tok2->previous()) {
if (tok2->str() == "{") {
endToken = tok2->link();
break;
}
}
// Rhs values..
if (!tok->astOperand2() || tok->astOperand2()->values.empty())
continue;
std::list<ValueFlow::Value> values = tok->astOperand2()->values;
const bool constValue = tok->astOperand2()->isNumber();
int indentlevel = 0;
unsigned int number_of_if = 0;
int varusagelevel = -1;
bool returnStatement = false; // current statement is a return, stop analysis at the ";"
for (Token *tok2 = tok; tok2 && tok2 != endToken; tok2 = tok2->next()) {
if (indentlevel >= 0 && tok2->str() == "{")
++indentlevel;
else if (indentlevel >= 0 && tok2->str() == "}")
--indentlevel;
if (Token::Match(tok2, "sizeof|typeof|typeid ("))
tok2 = tok2->linkAt(1);
// conditional block of code that assigns variable..
else if (Token::Match(tok2, "%var% (") && Token::simpleMatch(tok2->linkAt(1), ") {")) {
// Should scope be skipped because variable value is checked?
bool skip = false;
for (std::list<ValueFlow::Value>::iterator it = values.begin(); it != values.end(); ++it) {
if (conditionIsFalse(tok2->next()->astOperand2(), varid, *it)) {
skip = true;
break;
}
}
if (skip) {
// goto '{'
tok2 = tok2->linkAt(1)->next();
// goto '}'
tok2 = tok2->link();
continue;
}
Token * const start = tok2->linkAt(1)->next();
Token * const end = start->link();
bool varusage = (indentlevel >= 0 && constValue && number_of_if == 0U) ?
isVariableChanged(start,end,varid) :
(nullptr != Token::findmatch(start, "%varid%", end, varid));
if (varusage) {
varusagelevel = indentlevel;
// TODO: don't check noreturn scopes
if (number_of_if > 0U || Token::findmatch(tok2, "%varid%", start, varid)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " is assigned in conditional code");
break;
}
if (var->isStatic()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " bailout when conditional code that contains var is seen");
break;
}
// Remove conditional values
std::list<ValueFlow::Value>::iterator it;
for (it = values.begin(); it != values.end();) {
if (it->condition || it->conditional)
values.erase(it++);
else
++it;
}
}
// noreturn scopes..
if ((number_of_if > 0 || Token::findmatch(tok2, "%varid%", start, varid)) &&
(Token::findmatch(start, "return|continue|break", end) ||
(Token::simpleMatch(end,"} else {") && Token::findmatch(end, "return|continue|break", end->linkAt(2))))) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + ". noreturn conditional scope.");
break;
}
if (isVariableChanged(start, end, varid)) {
if (number_of_if == 0 &&
Token::simpleMatch(tok2, "if (") &&
!(Token::simpleMatch(end, "} else {") &&
(Token::findmatch(end, "%varid%", end->linkAt(2), varid) ||
Token::findmatch(end, "return|continue|break", end->linkAt(2))))) {
++number_of_if;
tok2 = end;
} else {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " is assigned in conditional code");
break;
}
}
}
else if (tok2->str() == "}" && indentlevel == varusagelevel) {
++number_of_if;
// Set "conditional" flag for all values
std::list<ValueFlow::Value>::iterator it;
for (it = values.begin(); it != values.end(); ++it)
it->conditional = true;
if (Token::simpleMatch(tok2,"} else {"))
tok2 = tok2->linkAt(2);
}
else if (indentlevel <= 0 && Token::Match(tok2, "break|continue|goto")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + ". noreturn conditional scope.");
break;
}
else if (indentlevel <= 0 && tok2->str() == "return")
returnStatement = true;
else if (returnStatement && tok2->str() == ";")
break;
if (tok2->varId() == varid) {
// bailout: assignment
if (Token::Match(tok2->previous(), "!!* %var% %op%") && tok2->next()->isAssignmentOp()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str());
break;
}
// bailout increment/decrement for now..
if (Token::Match(tok2->previous(), "++|-- %var%") || Token::Match(tok2, "%var% ++|--")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "increment/decrement of " + tok2->str());
break;
}
// bailout: possible assignment using >>
if (Token::Match(tok2->previous(), ">> %var% >>|;")) {
const Token *parent = tok2->previous();
while (Token::simpleMatch(parent,">>"))
parent = parent->astParent();
if (!parent) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "Possible assignment of " + tok2->str() + " using >>");
break;
}
}
// skip if variable is conditionally used in ?: expression
if (const Token *parent = skipValueInConditionalExpression(tok2)) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok2,
"no simplification of " + tok2->str() + " within " + (Token::Match(parent,"[?:]") ? "?:" : parent->str()) + " expression");
continue;
}
{
std::list<ValueFlow::Value>::const_iterator it;
for (it = values.begin(); it != values.end(); ++it)
setTokenValue(tok2, *it);
}
// assigned by subfunction?
bool inconclusive = false;
if (bailoutFunctionPar(tok2, ValueFlow::Value(), settings, &inconclusive)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction");
break;
}
if (inconclusive) {
std::list<ValueFlow::Value>::iterator it;
for (it = values.begin(); it != values.end(); ++it)
it->inconclusive = true;
}
}
}
}
}
static void execute(const Token *expr,
std::map<unsigned int, MathLib::bigint> * const programMemory,
MathLib::bigint *result,
bool *error)
{
if (!expr)
*error = true;
else if (expr->isNumber())
*result = MathLib::toLongNumber(expr->str());
else if (expr->varId() > 0) {
const std::map<unsigned int, MathLib::bigint>::const_iterator var = programMemory->find(expr->varId());
if (var == programMemory->end())
*error = true;
else
*result = var->second;
}
else if (expr->isComparisonOp()) {
MathLib::bigint result1(0), result2(0);
execute(expr->astOperand1(), programMemory, &result1, error);
execute(expr->astOperand2(), programMemory, &result2, error);
if (expr->str() == "<")
*result = result1 < result2;
else if (expr->str() == "<=")
*result = result1 <= result2;
else if (expr->str() == ">")
*result = result1 > result2;
else if (expr->str() == ">=")
*result = result1 >= result2;
else if (expr->str() == "==")
*result = result1 == result2;
else if (expr->str() == "!=")
*result = result1 != result2;
}
else if (expr->str() == "=") {
execute(expr->astOperand2(), programMemory, result, error);
if (!*error && expr->astOperand1() && expr->astOperand1()->varId())
(*programMemory)[expr->astOperand1()->varId()] = *result;
else
*error = true;
}
else if (expr->str() == "++" || expr->str() == "--") {
if (!expr->astOperand1() || expr->astOperand1()->varId() == 0U)
*error = true;
else {
std::map<unsigned int, MathLib::bigint>::iterator var = programMemory->find(expr->astOperand1()->varId());
if (var == programMemory->end())
*error = true;
else {
if (var->second == 0 &&
expr->str() == "--" &&
expr->astOperand1()->variable() &&
expr->astOperand1()->variable()->typeStartToken()->isUnsigned())
*error = true; // overflow
*result = var->second + (expr->str() == "++" ? 1 : -1);
var->second = *result;
}
}
}
else if (expr->isArithmeticalOp() && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint result1(0), result2(0);
execute(expr->astOperand1(), programMemory, &result1, error);
execute(expr->astOperand2(), programMemory, &result2, error);
if (expr->str() == "+")
*result = result1 + result2;
else if (expr->str() == "-")
*result = result1 - result2;
else if (expr->str() == "*")
*result = result1 * result2;
else if (result2 == 0)
*error = true;
else if (expr->str() == "/")
*result = result1 / result2;
else if (expr->str() == "%")
*result = result1 % result2;
}
else if (expr->str() == "&&") {
bool error1 = false;
execute(expr->astOperand1(), programMemory, result, &error1);
if (!error1 && *result == 0)
*result = 0;
else {
bool error2 = false;
execute(expr->astOperand2(), programMemory, result, &error2);
if (error1 && error2)
*error = true;
if (error2)
*result = 1;
else
*result = !!*result;
}
}
else if (expr->str() == "||") {
execute(expr->astOperand1(), programMemory, result, error);
if (*result == 0 && *error == false)
execute(expr->astOperand2(), programMemory, result, error);
}
else
*error = true;
}
static bool valueFlowForLoop1(const Token *tok, unsigned int * const varid, MathLib::bigint * const num1, MathLib::bigint * const num2)
{
tok = tok->tokAt(2);
if (!Token::Match(tok,"%type%| %var% ="))
return false;
const Token * const vartok = tok->tokAt(Token::Match(tok, "%var% =") ? 0 : 1);
if (vartok->varId() == 0U)
return false;
*varid = vartok->varId();
const Token * const num1tok = Token::Match(vartok->tokAt(2), "%num% ;") ? vartok->tokAt(2) : nullptr;
if (num1tok)
*num1 = MathLib::toLongNumber(num1tok->str());
tok = vartok->tokAt(2);
while (Token::Match(tok, "%var%|%num%|%or%|+|-|*|/|&|[|]|("))
tok = (tok->str() == "(") ? tok->link()->next() : tok->next();
if (!tok || tok->str() != ";")
return false;
tok = tok->next();
const Token *num2tok = nullptr;
if (Token::Match(tok, "%varid% <|<=|!=", vartok->varId())) {
tok = tok->next();
num2tok = tok->astOperand2();
if (num2tok && num2tok->str() == "(" && !num2tok->astOperand2())
num2tok = num2tok->astOperand1();
if (!Token::Match(num2tok, "%num%"))
num2tok = 0;
}
if (!num2tok)
return false;
*num2 = MathLib::toLongNumber(num2tok->str()) - ((tok->str()=="<=") ? 0 : 1);
if (!num1tok)
*num1 = *num2;
while (tok && tok->str() != ";")
tok = tok->next();
if (!Token::Match(tok, "; %varid% ++ ) {", vartok->varId()))
return false;
return true;
}
static bool valueFlowForLoop2(const Token *tok,
std::map<unsigned int, MathLib::bigint> *memory1,
std::map<unsigned int, MathLib::bigint> *memory2)
{
const Token *firstExpression = tok->next()->astOperand2()->astOperand1();
const Token *secondExpression = tok->next()->astOperand2()->astOperand2()->astOperand1();
const Token *thirdExpression = tok->next()->astOperand2()->astOperand2()->astOperand2();
std::map<unsigned int, MathLib::bigint> programMemory;
MathLib::bigint result(0);
bool error = false;
execute(firstExpression, &programMemory, &result, &error);
if (error)
return false;
execute(secondExpression, &programMemory, &result, &error);
std::map<unsigned int, MathLib::bigint> startMemory(programMemory);
std::map<unsigned int, MathLib::bigint> endMemory;
unsigned int maxcount = 10000;
while (result != 0 && !error && --maxcount) {
endMemory = programMemory;
execute(thirdExpression, &programMemory, &result, &error);
if (!error)
execute(secondExpression, &programMemory, &result, &error);
}
memory1->swap(startMemory);
if (!error)
memory2->swap(endMemory);
return true;
}
static void valueFlowForLoopSimplify(Token * const bodyStart, const unsigned int varid, const MathLib::bigint value, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
const Token * const bodyEnd = bodyStart->link();
// Is variable modified inside for loop
if (isVariableChanged(bodyStart, bodyEnd, varid))
return;
for (Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) {
if (tok2->varId() == varid) {
const Token * parent = tok2->astParent();
while (parent) {
const Token * const p = parent;
parent = parent->astParent();
if (parent && parent->str() == ":")
break;
if (parent && parent->str() == "?") {
if (parent->astOperand2() != p)
parent = NULL;
break;
}
}
if (parent) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop variable " + tok2->str() + " stopping on ?");
continue;
}
ValueFlow::Value value1(value);
value1.varId = tok2->varId();
setTokenValue(tok2, value1);
}
else if (Token::simpleMatch(tok2, ") {") && Token::findmatch(tok2->link(), "%varid%", tok2, varid)) {
if (Token::findmatch(tok2, "continue|break|return", tok2->linkAt(1), varid)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop variable bailout on conditional continue|break|return");
break;
}
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop variable skipping conditional scope");
tok2 = tok2->next()->link();
if (Token::simpleMatch(tok2, "} else {")) {
if (Token::findmatch(tok2, "continue|break|return", tok2->linkAt(2), varid)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop variable bailout on conditional continue|break|return");
break;
}
tok2 = tok2->linkAt(2);
}
}
}
}
static void valueFlowForLoop(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!Token::simpleMatch(tok, "for (") ||
!Token::simpleMatch(tok->next()->astOperand2(), ";") ||
!Token::simpleMatch(tok->next()->astOperand2()->astOperand2(), ";"))
continue;
Token * const bodyStart = tok->linkAt(1)->next();
unsigned int varid(0);
MathLib::bigint num1(0), num2(0);
if (valueFlowForLoop1(tok, &varid, &num1, &num2)) {
valueFlowForLoopSimplify(bodyStart, varid, num1, tokenlist, errorLogger, settings);
valueFlowForLoopSimplify(bodyStart, varid, num2, tokenlist, errorLogger, settings);
} else {
std::map<unsigned int, MathLib::bigint> mem1, mem2;
if (valueFlowForLoop2(tok, &mem1, &mem2)) {
std::map<unsigned int, MathLib::bigint>::const_iterator it;
for (it = mem1.begin(); it != mem1.end(); ++it)
valueFlowForLoopSimplify(bodyStart, it->first, it->second, tokenlist, errorLogger, settings);
for (it = mem2.begin(); it != mem2.end(); ++it)
valueFlowForLoopSimplify(bodyStart, it->first, it->second, tokenlist, errorLogger, settings);
}