420 lines
17 KiB
C++
420 lines
17 KiB
C++
/*
|
|
* Cppcheck - A tool for static C/C++ code analysis
|
|
* Copyright (C) 2007-2013 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>
|
|
|
|
|
|
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)
|
|
{
|
|
// passing variable to subfunction?
|
|
const bool addr = tok && Token::Match(tok->previous(), "&");
|
|
if (!tok || !Token::Match(tok->tokAt(addr?-2:-1), "[(,] &| %var% [,)]"))
|
|
return false;
|
|
|
|
// 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() : NULL;
|
|
if (!Token::Match(tok,"%var% ("))
|
|
return false; // not a function => dont bailout
|
|
|
|
if (!tok->function())
|
|
return true; // unknown function bailout
|
|
|
|
const Variable *arg = tok->function()->getArgumentVar(argnr);
|
|
|
|
return arg && !arg->isConst() && arg->isReference();
|
|
}
|
|
|
|
static const Token * skipValueInConditionalExpression(const Token *tok)
|
|
{
|
|
while (tok && !Token::Match(tok, "%oror%|&&|?|:")) {
|
|
while (Token::Match(tok->astParent(), "%oror%|&&|?") && tok->astParent()->astOperand1() == tok)
|
|
tok = tok->astParent();
|
|
tok = tok->astParent();
|
|
}
|
|
return tok;
|
|
}
|
|
|
|
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 != NULL &&
|
|
parent->astOperand2() == op &&
|
|
parent->astOperand1() != NULL &&
|
|
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 void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
|
|
{
|
|
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
|
|
unsigned int varid;
|
|
MathLib::bigint num;
|
|
const Variable *var;
|
|
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->isGlobal() && !var->isConst()) {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok, "global variable " + var->nameToken()->str());
|
|
continue;
|
|
}
|
|
|
|
// bailout: while-condition, variable is changed in while loop
|
|
for (const Token *tok2 = tok; tok2; tok2 = tok2->previous()) {
|
|
if (tok2->str() == ")")
|
|
tok2 = tok2->link();
|
|
else if (tok2->str() == "(") {
|
|
if (Token::Match(tok2->previous(), "for|while (") && Token::Match(tok2->link(), ") {")) {
|
|
const Token *start = tok2->link()->next();
|
|
const Token *end = start->link();
|
|
if (Token::findmatch(start,"++|--| %varid% ++|--|=",end,varid))
|
|
varid = 0U;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
if (varid == 0U) {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok, "variable " + var->nameToken()->str() + " used in loop ");
|
|
continue;
|
|
}
|
|
|
|
// extra logic for unsigned variables 'i>=1' => possible value can also be 0
|
|
const ValueFlow::Value val(tok, num);
|
|
ValueFlow::Value val2;
|
|
if (num==1U && Token::Match(tok,"<=|>=")) {
|
|
bool isunsigned = var->typeEndToken()->isUnsigned();
|
|
for (const Token* type = var->typeStartToken(); type != var->typeEndToken(); type = type->next())
|
|
isunsigned |= type->isUnsigned();
|
|
if (isunsigned)
|
|
val2 = ValueFlow::Value(tok,0);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
// 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;
|
|
}
|
|
|
|
// assigned by subfunction?
|
|
if (bailoutFunctionPar(tok2)) {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction");
|
|
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;
|
|
}
|
|
|
|
tok2->values.push_back(val);
|
|
if (val2.condition)
|
|
tok2->values.push_back(val2);
|
|
if (var && tok2 == var->nameToken())
|
|
break;
|
|
}
|
|
|
|
// skip sizeof..
|
|
if (tok2->str() == ")" && Token::Match(tok2->link()->previous(), "typeof|sizeof ("))
|
|
tok2 = tok2->link();
|
|
|
|
if (tok2->str() == "}") {
|
|
if (Token::findmatch(tok2->link(), "%varid%", tok2, varid)) {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " stopping on }");
|
|
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::Match(tok2->previous(), "do") ||
|
|
(tok2->str() == ")" && Token::Match(tok2->linkAt(-1)->previous(), "for|while (")))) {
|
|
|
|
const Token *start = tok2;
|
|
const Token *end = start->link();
|
|
if (Token::findmatch(start,"++|--| %varid% ++|--|=",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->isGlobal()) {
|
|
if (!Token::Match(tok2->previous(), ")|else {"))
|
|
break;
|
|
if (Token::Match(tok2->previous(), ") {") &&
|
|
!Token::Match(tok2->linkAt(-1)->previous(), "if|for|while ("))
|
|
break;
|
|
}
|
|
} else if (tok2->str() == "break") {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " stopping on break");
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void valueFlowForLoop(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
|
|
{
|
|
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
|
|
if (!Token::Match(tok, "for ("))
|
|
continue;
|
|
|
|
tok = tok->tokAt(2);
|
|
if (!Token::Match(tok,"%type%| %var% = %num% ;")) { // TODO: don't use %num%
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok, "For loop not handled");
|
|
continue;
|
|
}
|
|
Token * const vartok = tok->tokAt(Token::Match(tok, "%var% =") ? 0 : 1);
|
|
const MathLib::bigint num1 = MathLib::toLongNumber(vartok->strAt(2));
|
|
if (vartok->varId() == 0U)
|
|
continue;
|
|
tok = vartok->tokAt(4);
|
|
const Token *num2tok = 0;
|
|
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) {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok, "For loop not handled");
|
|
continue;
|
|
}
|
|
const MathLib::bigint num2 = MathLib::toLongNumber(num2tok ? num2tok->str() : "0") - ((tok->str()=="<=") ? 0 : 1);
|
|
while (tok && tok->str() != ";")
|
|
tok = tok->next();
|
|
if (!num2tok || !Token::Match(tok, "; %varid% ++ ) {", vartok->varId())) {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok, "For loop not handled");
|
|
continue;
|
|
}
|
|
|
|
Token * const bodyStart = tok->tokAt(4);
|
|
const Token * const bodyEnd = bodyStart->link();
|
|
|
|
// Is variable modified inside for loop
|
|
bool modified = false;
|
|
for (const Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) {
|
|
if (Token::Match(tok2, "%varid% =", vartok->varId())) {
|
|
modified = true;
|
|
break;
|
|
}
|
|
}
|
|
if (modified)
|
|
continue;
|
|
|
|
for (Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) {
|
|
if (tok2->varId() == vartok->varId()) {
|
|
tok2->values.push_back(ValueFlow::Value(num1));
|
|
tok2->values.push_back(ValueFlow::Value(num2));
|
|
}
|
|
|
|
if (tok2->str() == "{") {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok2, "For loop variable " + vartok->str() + " stopping on {");
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void valueFlowSubFunction(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
|
|
{
|
|
std::list<ValueFlow::Value> argvalues;
|
|
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
|
|
if (!Token::Match(tok, "[(,]"))
|
|
continue;
|
|
|
|
// passing value(s) to function
|
|
if (Token::Match(tok, "[(,] %var% [,)]") && !tok->next()->values.empty())
|
|
argvalues = tok->next()->values;
|
|
else if (Token::Match(tok, "[(,] %num% [,)]")) {
|
|
argvalues.clear();
|
|
argvalues.push_back(ValueFlow::Value(MathLib::toLongNumber(tok->next()->str())));
|
|
} else {
|
|
// bool operator => values 1/0 are passed to function..
|
|
const Token *op = tok->next();
|
|
while (op && op->astParent() && !Token::Match(op->astParent(), "[(,]"))
|
|
op = op->astParent();
|
|
if (Token::Match(op, "%comp%|%oror%|&&|!")) {
|
|
argvalues.clear();
|
|
argvalues.push_back(ValueFlow::Value(0));
|
|
argvalues.push_back(ValueFlow::Value(1));
|
|
} else {
|
|
// possible values are unknown..
|
|
continue;
|
|
}
|
|
}
|
|
|
|
const Token * const argumentToken = tok->next();
|
|
|
|
// is this a function call?
|
|
const Token *ftok = tok;
|
|
while (ftok && ftok->str() != "(")
|
|
ftok = ftok->astParent();
|
|
if (!ftok || !ftok->astOperand1() || !ftok->astOperand2() || !ftok->astOperand1()->function())
|
|
continue;
|
|
|
|
// Get argument nr
|
|
unsigned int argnr = 0;
|
|
for (const Token *argtok = ftok->next(); argtok && argtok != argumentToken; argtok = argtok->nextArgument())
|
|
++ argnr;
|
|
|
|
// Get function argument, and check if parameter is passed by value
|
|
const Function * const function = ftok->astOperand1()->function();
|
|
const Variable * const arg = function ? function->getArgumentVar(argnr) : NULL;
|
|
if (!Token::Match(arg ? arg->typeStartToken() : NULL, "const| %type% %var% ,|)"))
|
|
continue;
|
|
|
|
// Function scope..
|
|
const Scope * const functionScope = function ? function->functionScope : NULL;
|
|
if (!functionScope)
|
|
continue;
|
|
|
|
// Set value in function scope..
|
|
const unsigned int varid2 = arg->nameToken()->varId();
|
|
for (const Token *tok2 = functionScope->classStart->next(); tok2 != functionScope->classEnd; tok2 = tok2->next()) {
|
|
if (Token::Match(tok2, "%varid% !!=", varid2)) {
|
|
std::list<ValueFlow::Value> &values = const_cast<Token*>(tok2)->values;
|
|
values.insert(values.begin(), argvalues.begin(), argvalues.end());
|
|
} else if (tok2->str() == "{") {
|
|
if (settings->debugwarnings)
|
|
bailout(tokenlist, errorLogger, tok2, "parameter " + arg->nameToken()->str());
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void ValueFlow::setValues(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
|
|
{
|
|
for (Token *tok = tokenlist->front(); tok; tok = tok->next())
|
|
tok->values.clear();
|
|
|
|
valueFlowForLoop(tokenlist, errorLogger, settings);
|
|
valueFlowBeforeCondition(tokenlist, errorLogger, settings);
|
|
valueFlowSubFunction(tokenlist, errorLogger, settings);
|
|
}
|