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valueflow.cpp
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2508 lines (2262 loc) · 104 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2016 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 "astutils.h"
#include "errorlogger.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenlist.h"
#include <stack>
namespace {
struct ProgramMemory {
std::map<unsigned int, MathLib::bigint> intvalues;
std::map<unsigned int, const Token *> tokvalues;
void setValue(unsigned int varid, const ValueFlow::Value &value) {
if (value.tokvalue) {
intvalues.erase(varid);
tokvalues[varid] = value.tokvalue;
} else {
intvalues[varid] = value.intvalue;
tokvalues.erase(varid);
}
}
bool getIntValue(unsigned int varid, MathLib::bigint* result) const {
const std::map<unsigned int, MathLib::bigint>::const_iterator it = intvalues.find(varid);
if (it != intvalues.end())
*result = it->second;
return (it != intvalues.end());
}
void setIntValue(unsigned int varid, MathLib::bigint value) {
intvalues[varid] = value;
tokvalues.erase(varid);
}
bool hasValue(unsigned int varid) {
return intvalues.find(varid) != intvalues.end() ||
tokvalues.find(varid) != tokvalues.end();
}
void swap(ProgramMemory &pm) {
intvalues.swap(pm.intvalues);
tokvalues.swap(pm.tokvalues);
}
void clear() {
intvalues.clear();
tokvalues.clear();
}
bool empty() const {
return intvalues.empty() && tokvalues.empty();
}
};
}
static void execute(const Token *expr,
ProgramMemory * const programMemory,
MathLib::bigint *result,
bool *error);
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, tokenlist->getSourceFilePath(), 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), ") & %name% [,)]") && Token::Match(tok->linkAt(-2)->previous(), "[,(] ("))
;
else if (Token::Match(tok->tokAt(addressOf?-2:-1), "[(,] &| %name% [,)]"))
;
else
return false;
// reinterpret_cast etc..
if (Token::Match(tok->tokAt(-3), "> ( & %name% ) [,)]") &&
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 (tok && tok->link() && tok->str() == ">")
tok = tok->link()->previous();
if (!Token::Match(tok, "%name% ("))
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, 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 programMemory program memory
*/
static bool conditionIsFalse(const Token *condition, const ProgramMemory &programMemory)
{
if (!condition)
return false;
if (condition->str() == "&&") {
const bool result1 = conditionIsFalse(condition->astOperand1(), programMemory);
const bool result2 = result1 ? true : conditionIsFalse(condition->astOperand2(), programMemory);
return result2;
}
ProgramMemory progmem(programMemory);
MathLib::bigint result = 0;
bool error = false;
execute(condition, &progmem, &result, &error);
return !error && result == 0;
}
/**
* Is condition always true when variable has given value?
* \param condition top ast token in condition
* \param programMemory program memory
*/
static bool conditionIsTrue(const Token *condition, const ProgramMemory &programMemory)
{
if (!condition)
return false;
if (condition->str() == "||") {
const bool result1 = conditionIsTrue(condition->astOperand1(), programMemory);
const bool result2 = result1 ? true : conditionIsTrue(condition->astOperand2(), programMemory);
return result2;
}
ProgramMemory progmem(programMemory);
bool error = false;
MathLib::bigint result = 0;
execute(condition, &progmem, &result, &error);
return !error && result == 1;
}
/**
* Get program memory by looking backwards from given token.
*/
static ProgramMemory getProgramMemory(const Token *tok, unsigned int varid, const ValueFlow::Value &value)
{
ProgramMemory programMemory;
programMemory.setValue(varid, value);
if (value.varId)
programMemory.setIntValue(value.varId, value.varvalue);
const ProgramMemory programMemory1(programMemory);
int indentlevel = 0;
for (const Token *tok2 = tok; tok2; tok2 = tok2->previous()) {
if (Token::Match(tok2, "[;{}] %varid% = %var% ;", varid)) {
const Token *vartok = tok2->tokAt(3);
programMemory.setValue(vartok->varId(), value);
}
if (Token::Match(tok2, "[;{}] %var% =")) {
const Token *vartok = tok2->next();
if (!programMemory.hasValue(vartok->varId())) {
MathLib::bigint result = 0;
bool error = false;
execute(tok2->tokAt(2)->astOperand2(), &programMemory, &result, &error);
if (!error)
programMemory.setIntValue(vartok->varId(), result);
}
}
if (tok2->str() == "{") {
if (indentlevel <= 0)
break;
--indentlevel;
}
if (tok2->str() == "}") {
const Token *cond = tok2->link();
cond = Token::simpleMatch(cond->previous(), ") {") ? cond->linkAt(-1) : nullptr;
if (cond && conditionIsFalse(cond->astOperand2(), programMemory1))
tok2 = cond->previous();
else if (cond && conditionIsTrue(cond->astOperand2(), programMemory1)) {
++indentlevel;
continue;
} else
break;
}
}
return programMemory;
}
/**
* 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 || tok2->str() == ".")
continue;
// A variable is seen..
if (tok2 != valuetok && tok2->variable() && (tok2->varId() == valuetok->varId() || !tok2->variable()->isArgument())) {
// TODO: limit this bailout
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;
}
/** Add token value. Return true if value is added. */
static bool addValue(Token *tok, const ValueFlow::Value &value)
{
if (value.isKnown()) {
// Clear all other values since value is known
tok->values.clear();
}
// Don't handle more than 10 values for performance reasons
// TODO: add setting?
if (tok->values.size() >= 10U)
return false;
// 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) {
// different intvalue => continue
if (it->intvalue != value.intvalue)
continue;
// different tokvalue => continue
if ((it->tokvalue == nullptr) != (value.tokvalue == nullptr))
continue;
if ((value.tokvalue != nullptr) && (it->tokvalue != value.tokvalue) && (it->tokvalue->str() != value.tokvalue->str()))
continue;
// same value, but old value is inconclusive so replace it
if (it->inconclusive && !value.inconclusive) {
*it = value;
if (it->varId == 0)
it->varId = tok->varId();
break;
}
// Same value already exists, don't add new value
return false;
}
// Add value
if (it == tok->values.end()) {
ValueFlow::Value v(value);
if (v.varId == 0)
v.varId = tok->varId();
tok->values.push_back(v);
}
return true;
}
/** set ValueFlow value and perform calculations if possible */
static void setTokenValue(Token* tok, const ValueFlow::Value &value)
{
if (!addValue(tok,value))
return;
Token *parent = const_cast<Token*>(tok->astParent());
if (!parent)
return;
// Cast..
if (parent->str() == "(" && tok == parent->link()->next()) {
setTokenValue(parent,value);
}
else if (parent->str() == ":") {
setTokenValue(parent,value);
}
else if (parent->str() == "?" && tok->str() == ":" && tok == parent->astOperand2() && parent->astOperand1()) {
// is condition always true/false?
if (parent->astOperand1()->values.size() == 1U && parent->astOperand1()->values.front().isKnown()) {
const ValueFlow::Value &condvalue = parent->astOperand1()->values.front();
const bool cond(condvalue.tokvalue || condvalue.intvalue != 0);
if (cond && !tok->astOperand1()) { // true condition, no second operator
setTokenValue(parent, condvalue);
} else {
const Token *op = cond ? tok->astOperand1() : tok->astOperand2();
const std::list<ValueFlow::Value> &values = op->values;
if (std::find(values.begin(), values.end(), value) != values.end())
setTokenValue(parent, value);
}
} else {
// is condition only depending on 1 variable?
std::stack<const Token*> tokens;
tokens.push(parent->astOperand1());
unsigned int varId = 0;
while (!tokens.empty()) {
const Token *t = tokens.top();
tokens.pop();
if (!t)
continue;
tokens.push(t->astOperand1());
tokens.push(t->astOperand2());
if (t->varId()) {
if (varId > 0 || value.varId != 0U)
return;
varId = t->varId();
} else if (t->str() == "(" && Token::Match(t->previous(), "%name%"))
return; // function call
}
ValueFlow::Value v(value);
v.conditional = true;
v.changeKnownToPossible();
if (varId)
v.varId = varId;
setTokenValue(parent, v);
}
}
// Calculations..
else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp)) &&
parent->astOperand1() &&
parent->astOperand2()) {
const bool known = ((parent->astOperand1()->values.size() == 1U &&
parent->astOperand1()->values.front().isKnown()) ||
(parent->astOperand2()->values.size() == 1U &&
parent->astOperand2()->values.front().isKnown()));
// known result when a operand is 0.
if (Token::Match(parent, "[&*]") && value.isKnown() && value.tokvalue==nullptr && value.intvalue==0) {
setTokenValue(parent, value);
return;
}
std::list<ValueFlow::Value>::const_iterator value1, value2;
for (value1 = parent->astOperand1()->values.begin(); value1 != parent->astOperand1()->values.end(); ++value1) {
if (value1->tokvalue && (!parent->isComparisonOp() || value1->tokvalue->tokType() != Token::eString))
continue;
for (value2 = parent->astOperand2()->values.begin(); value2 != parent->astOperand2()->values.end(); ++value2) {
if (value2->tokvalue && (!parent->isComparisonOp() || value2->tokvalue->tokType() != Token::eString || value1->tokvalue))
continue;
if (known || value1->varId == 0U || value2->varId == 0U ||
(value1->varId == value2->varId && value1->varvalue == value2->varvalue && !value1->tokvalue && !value2->tokvalue)) {
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;
if (value1->valueKind == value2->valueKind)
result.valueKind = value1->valueKind;
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;
case '=':
if (parent->str() == "==") {
if (value1->tokvalue || value2->tokvalue)
result.intvalue = 0;
else
result.intvalue = value1->intvalue == value2->intvalue;
setTokenValue(parent, result);
}
break;
case '!':
if (parent->str() == "!=") {
if (value1->tokvalue || value2->tokvalue)
result.intvalue = 1;
else
result.intvalue = value1->intvalue != value2->intvalue;
setTokenValue(parent, result);
}
break;
case '>':
if (value1->tokvalue || value2->tokvalue)
break;
if (parent->str() == ">")
result.intvalue = value1->intvalue > value2->intvalue;
else if (parent->str() == ">=")
result.intvalue = value1->intvalue >= value2->intvalue;
else
break;
setTokenValue(parent, result);
break;
case '<':
if (value1->tokvalue || value2->tokvalue)
break;
if (parent->str() == "<")
result.intvalue = value1->intvalue < value2->intvalue;
else if (parent->str() == "<=")
result.intvalue = value1->intvalue <= value2->intvalue;
else
break;
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 '^':
result.intvalue = value1->intvalue ^ value2->intvalue;
setTokenValue(parent, result);
break;
default:
// unhandled operator, do nothing
break;
}
}
}
}
}
// !
else if (parent->str() == "!") {
std::list<ValueFlow::Value>::const_iterator it;
for (it = tok->values.begin(); it != tok->values.end(); ++it) {
if (it->tokvalue)
continue;
ValueFlow::Value v(*it);
v.intvalue = !v.intvalue;
setTokenValue(parent, v);
}
}
// unary minus
else if (parent->str() == "-" && !parent->astOperand2()) {
std::list<ValueFlow::Value>::const_iterator it;
for (it = tok->values.begin(); it != tok->values.end(); ++it) {
if (it->tokvalue)
continue;
ValueFlow::Value v(*it);
v.intvalue = -v.intvalue;
setTokenValue(parent, v);
}
}
// Array element
else if (parent->str() == "[" && parent->astOperand1() && parent->astOperand2()) {
std::list<ValueFlow::Value>::const_iterator value1, value2;
for (value1 = parent->astOperand1()->values.begin(); value1 != parent->astOperand1()->values.end(); ++value1) {
if (!value1->tokvalue)
continue;
for (value2 = parent->astOperand2()->values.begin(); value2 != parent->astOperand2()->values.end(); ++value2) {
if (value2->tokvalue)
continue;
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;
if (value1->valueKind == value2->valueKind)
result.valueKind = value1->valueKind;
if (value1->tokvalue->tokType() == Token::eString) {
const std::string s = value1->tokvalue->strValue();
const MathLib::bigint index = value2->intvalue;
if (index == s.size()) {
result.intvalue = 0;
setTokenValue(parent, result);
} else if (index >= 0 && index < s.size()) {
result.intvalue = s[index];
setTokenValue(parent, result);
}
} else if (value1->tokvalue->str() == "{") {
MathLib::bigint index = value2->intvalue;
const Token *element = value1->tokvalue->next();
while (index > 0 && element->str() != "}") {
if (element->str() == ",")
--index;
if (Token::Match(element, "[{}()[]]"))
break;
element = element->next();
}
if (Token::Match(element, "%num% [,}]")) {
result.intvalue = MathLib::toLongNumber(element->str());
setTokenValue(parent, result);
}
}
}
}
}
}
}
// Handle various constants..
static Token * valueFlowSetConstantValue(const Token *tok, const Settings *settings)
{
if ((tok->isNumber() && MathLib::isInt(tok->str())) || (tok->tokType() == Token::eChar)) {
ValueFlow::Value value(MathLib::toLongNumber(tok->str()));
value.setKnown();
setTokenValue(const_cast<Token *>(tok), value);
} else if (tok->enumerator() && tok->enumerator()->value_known) {
ValueFlow::Value value(tok->enumerator()->value);
value.setKnown();
setTokenValue(const_cast<Token *>(tok), value);
} else if (Token::simpleMatch(tok, "sizeof (") && tok->tokAt(2)) {
const Token *tok2 = tok->tokAt(2);
if (tok2->enumerator() && tok2->enumerator()->scope) {
long long size = settings->sizeof_int;
const Token * type = tok2->enumerator()->scope->enumType;
if (type) {
size = type->str() == "char" ? 1 :
type->str() == "short" ? settings->sizeof_short :
type->str() == "int" ? settings->sizeof_int :
(type->str() == "long" && type->isLong()) ? settings->sizeof_long_long :
type->str() == "long" ? settings->sizeof_long : 0;
}
ValueFlow::Value value(size);
value.setKnown();
setTokenValue(const_cast<Token *>(tok), value);
setTokenValue(const_cast<Token *>(tok->next()), value);
} else if (tok2->type() && tok2->type()->isEnumType()) {
long long size = settings->sizeof_int;
const Token * type = tok2->type()->classScope->enumType;
if (type) {
size = type->str() == "char" ? 1 :
type->str() == "short" ? settings->sizeof_short :
type->str() == "int" ? settings->sizeof_int :
(type->str() == "long" && type->isLong()) ? settings->sizeof_long_long :
type->str() == "long" ? settings->sizeof_long : 0;
}
ValueFlow::Value value(size);
value.setKnown();
setTokenValue(const_cast<Token *>(tok), value);
setTokenValue(const_cast<Token *>(tok->next()), value);
}
// skip over enum
tok = tok->linkAt(1);
}
return tok->next();
}
static void valueFlowNumber(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok;) {
tok = valueFlowSetConstantValue(tok, tokenlist->getSettings());
}
if (tokenlist->isCPP()) {
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->isName() && !tok->varId() && Token::Match(tok, "false|true")) {
ValueFlow::Value value(tok->str() == "true");
value.setKnown();
setTokenValue(tok, value);
} else if (Token::Match(tok, "[(,] NULL [,)]")) {
// NULL function parameters are not simplified in the
// normal tokenlist
ValueFlow::Value value(0);
value.setKnown();
setTokenValue(tok->next(), value);
}
}
}
}
static void valueFlowString(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->tokType() == Token::eString) {
ValueFlow::Value strvalue;
strvalue.tokvalue = tok;
strvalue.setKnown();
setTokenValue(tok, strvalue);
}
}
}
static void valueFlowArray(TokenList *tokenlist)
{
std::map<unsigned int, const Token *> constantArrays;
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->varId() > 0U) {
const std::map<unsigned int, const Token *>::const_iterator it = constantArrays.find(tok->varId());
if (it != constantArrays.end()) {
ValueFlow::Value value;
value.tokvalue = it->second;
value.setKnown();
setTokenValue(tok, value);
}
// pointer = array
else if (tok->variable() &&
tok->variable()->isArray() &&
Token::simpleMatch(tok->astParent(), "=") &&
tok == tok->astParent()->astOperand2() &&
tok->astParent()->astOperand1() &&
tok->astParent()->astOperand1()->variable() &&
tok->astParent()->astOperand1()->variable()->isPointer()) {
ValueFlow::Value value;
value.tokvalue = tok;
value.setKnown();
setTokenValue(tok, value);
}
continue;
}
if (Token::Match(tok, "const %type% %var% [ %num%| ] = {")) {
const Token *vartok = tok->tokAt(2);
const Token *rhstok = vartok->next()->link()->tokAt(2);
constantArrays[vartok->varId()] = rhstok;
tok = rhstok->link();
continue;
}
else if (Token::Match(tok, "const char %var% [ %num%| ] = %str% ;")) {
const Token *vartok = tok->tokAt(2);
const Token *strtok = vartok->next()->link()->tokAt(2);
constantArrays[vartok->varId()] = strtok;
tok = strtok->next();
continue;
}
}
}
static void valueFlowPointerAlias(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
// not address of
if (tok->str() != "&" || tok->astOperand2())
continue;
// parent should be a '='
if (!Token::simpleMatch(tok->astParent(), "="))
continue;
// child should be some buffer or variable
const Token *vartok = tok->astOperand1();
while (vartok) {
if (vartok->str() == "[")
vartok = vartok->astOperand1();
else if (vartok->str() == "." || vartok->str() == "::")
vartok = vartok->astOperand2();
else
break;
}
if (!(vartok && vartok->variable() && !vartok->variable()->isPointer()))
continue;
ValueFlow::Value value;
value.tokvalue = tok;
setTokenValue(tok, value);
}
}
static void valueFlowBitAnd(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->str() != "&")
continue;
if (tok->values.size() == 1U && tok->values.front().isKnown())
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 valueFlowOppositeCondition(SymbolDatabase *symboldatabase, const Settings *settings)
{
for (std::list<Scope>::iterator scope = symboldatabase->scopeList.begin(); scope != symboldatabase->scopeList.end(); ++scope) {
if (scope->type != Scope::eIf)
continue;
Token *tok = const_cast<Token *>(scope->classDef);
if (!Token::simpleMatch(tok, "if ("))
continue;
const Token *cond1 = tok->next()->astOperand2();
if (!cond1 || !cond1->isComparisonOp())
continue;
const bool cpp = symboldatabase->isCPP();
Token *tok2 = tok->linkAt(1);
while (Token::simpleMatch(tok2, ") {")) {
tok2 = tok2->linkAt(1);
if (!Token::simpleMatch(tok2, "} else { if ("))
break;
const Token *cond2 = tok2->tokAt(4)->astOperand2();
if (!cond2 || !cond2->isComparisonOp())
continue;
if (isOppositeCond(true, cpp, cond1, cond2, settings->library.functionpure)) {
ValueFlow::Value value(1);
value.setKnown();
setTokenValue(const_cast<Token*>(cond2), value);
}
tok2 = tok2->linkAt(4);
}
}
}
static void valueFlowReverse(TokenList *tokenlist,
Token *tok,
const Token * const varToken,
ValueFlow::Value val,
ValueFlow::Value val2,
ErrorLogger *errorLogger,
const Settings *settings)
{
const MathLib::bigint num = val.intvalue;
const Variable * const var = varToken->variable();
if (!var)
return;
const unsigned int varid = varToken->varId();
const Token * const startToken = var->nameToken();
for (Token *tok2 = tok->previous(); ; tok2 = tok2->previous()) {
if (!tok2 ||
tok2 == startToken ||
(tok2->str() == "{" && tok2->scope()->type == Scope::ScopeType::eFunction)) {
break;
}
if (tok2->varId() == varid) {
// bailout: assignment
if (Token::Match(tok2->previous(), "!!* %name% =")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str());
break;
}
// increment/decrement
if (Token::Match(tok2->previous(), "[;{}] %name% ++|-- ;"))
val.intvalue += (tok2->strAt(1)=="++") ? -1 : 1;
else if (Token::Match(tok2->tokAt(-2), "[;{}] ++|-- %name% ;"))
val.intvalue += (tok2->strAt(-1)=="++") ? -1 : 1;
else if (Token::Match(tok2->previous(), "++|-- %name%") || Token::Match(tok2, "%name% ++|--")) {
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,"%name%|.") && 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 (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, "[;{}] %name% :")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2->next(), "variable " + var->name() + " stopping on goto label");
break;
}
if (tok2->str() == "}") {
const Token *vartok = Token::findmatch(tok2->link(), "%varid%", tok2, varid);
while (Token::Match(vartok, "%name% = %num% ;") && !vartok->tokAt(2)->getValue(num))
vartok = Token::findmatch(vartok->next(), "%varid%", tok2, varid);
if (vartok) {
if (settings->debugwarnings) {
std::string errmsg = "variable ";
errmsg += var->name() + " ";
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->name() + " 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 ((tok2->previous()->str() == ")") &&
!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->name() + " stopping on " + parent->str());
break;
}
}
}
}
static void valueFlowBeforeCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
const std::size_t functions = symboldatabase->functionScopes.size();
for (std::size_t i = 0; i < functions; ++i) {
const Scope * scope = symboldatabase->functionScopes[i];
for (Token* tok = const_cast<Token*>(scope->classStart); tok != scope->classEnd; tok = tok->next()) {
MathLib::bigint num = 0;
const Token *vartok = nullptr;
if (tok->isComparisonOp() && tok->astOperand1() && tok->astOperand2()) {
if (tok->astOperand1()->isName() && tok->astOperand2()->isNumber()) {
vartok = tok->astOperand1();
num = MathLib::toLongNumber(tok->astOperand2()->str());
} else if (tok->astOperand1()->isNumber() && tok->astOperand2()->isName()) {
vartok = tok->astOperand2();
num = MathLib::toLongNumber(tok->astOperand1()->str());
} else {
continue;
}
} else if (Token::Match(tok->previous(), "if|while ( %name% %oror%|&&|)") ||
Token::Match(tok, "%oror%|&& %name% %oror%|&&|)")) {
vartok = tok->next();
num = 0;
} else if (tok->str() == "!" && tok->astOperand1() && tok->astOperand1()->isName()) {
vartok = tok->astOperand1();
num = 0;
} else {
continue;
}
unsigned int varid = vartok->varId();