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cppcheck/lib/valueflow.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2020 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/>.
*/
/**
* @brief This is the ValueFlow component in Cppcheck.
*
* Each @sa Token in the token list has a list of values. These are
* the "possible" values for the Token at runtime.
*
* In the --debug and --debug-normal output you can see the ValueFlow data. For example:
*
* int f()
* {
* int x = 10;
* return 4 * x + 2;
* }
*
* The --debug-normal output says:
*
* ##Value flow
* Line 3
* 10 always 10
* Line 4
* 4 always 4
* * always 40
* x always 10
* + always 42
* 2 always 2
*
* All value flow analysis is executed in the ValueFlow::setValues() function. The ValueFlow analysis is executed after
* the tokenizer/ast/symboldatabase/etc.. The ValueFlow analysis is done in a series of valueFlow* function calls, where
* each such function call can only use results from previous function calls. The function calls should be arranged so
* that valueFlow* that do not require previous ValueFlow information should be first.
*
* Type of analysis
* ================
*
* This is "flow sensitive" value flow analysis. We _usually_ track the value for 1 variable at a time.
*
* How are calculations handled
* ============================
*
* Here is an example code:
*
* x = 3 + 4;
*
* The valueFlowNumber set the values for the "3" and "4" tokens by calling setTokenValue().
* The setTokenValue() handle the calculations automatically. When both "3" and "4" have values, the "+" can be
* calculated. setTokenValue() recursively calls itself when parents in calculations can be calculated.
*
* Forward / Reverse flow analysis
* ===============================
*
* In forward value flow analysis we know a value and see what happens when we are stepping the program forward. Like
* normal execution. The valueFlowForwardVariable is used in this analysis.
*
* In reverse value flow analysis we know the value of a variable at line X. And try to "execute backwards" to determine
* possible values before line X. The valueFlowReverse is used in this analysis.
*
*
*/
#include "valueflow.h"
#include "astutils.h"
#include "errorlogger.h"
#include "forwardanalyzer.h"
#include "library.h"
#include "mathlib.h"
#include "path.h"
#include "platform.h"
#include "programmemory.h"
#include "settings.h"
#include "standards.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenlist.h"
#include "utils.h"
#include "valueptr.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstring>
#include <functional>
#include <iterator>
#include <limits>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <vector>
static void bailoutInternal(TokenList *tokenlist, ErrorLogger *errorLogger, const Token *tok, const std::string &what, const std::string &file, int line, const std::string &function)
{
std::list<ErrorMessage::FileLocation> callstack(1, ErrorMessage::FileLocation(tok, tokenlist));
ErrorMessage errmsg(callstack, tokenlist->getSourceFilePath(), Severity::debug,
Path::stripDirectoryPart(file) + ":" + MathLib::toString(line) + ":" + function + " bailout: " + what, "valueFlowBailout", false);
errorLogger->reportErr(errmsg);
}
#if (defined __cplusplus) && __cplusplus >= 201103L
#define bailout(tokenlist, errorLogger, tok, what) bailoutInternal(tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __func__)
#elif (defined __GNUC__) || (defined __clang__) || (defined _MSC_VER)
#define bailout(tokenlist, errorLogger, tok, what) bailoutInternal(tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __FUNCTION__)
#else
#define bailout(tokenlist, errorLogger, tok, what) bailoutInternal(tokenlist, errorLogger, tok, what, __FILE__, __LINE__, "(valueFlow)")
#endif
static void changeKnownToPossible(std::list<ValueFlow::Value> &values, int indirect=-1)
{
for (ValueFlow::Value& v: values) {
if (indirect >= 0 && v.indirect != indirect)
continue;
v.changeKnownToPossible();
}
}
static void removeImpossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
values.remove_if([&](const ValueFlow::Value& v) {
if (indirect >= 0 && v.indirect != indirect)
return false;
return v.isImpossible();
});
}
static void lowerToPossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
changeKnownToPossible(values, indirect);
removeImpossible(values, indirect);
}
static void changePossibleToKnown(std::list<ValueFlow::Value>& values, int indirect = -1)
{
for (ValueFlow::Value& v : values) {
if (indirect >= 0 && v.indirect != indirect)
continue;
if (!v.isPossible())
continue;
if (v.bound != ValueFlow::Value::Bound::Point)
continue;
v.setKnown();
}
}
static void setValueUpperBound(ValueFlow::Value& value, bool upper)
{
if (upper)
value.bound = ValueFlow::Value::Bound::Upper;
else
value.bound = ValueFlow::Value::Bound::Lower;
}
static void setValueBound(ValueFlow::Value& value, const Token* tok, bool invert)
{
if (Token::Match(tok, "<|<=")) {
setValueUpperBound(value, !invert);
} else if (Token::Match(tok, ">|>=")) {
setValueUpperBound(value, invert);
}
}
static void setConditionalValues(const Token *tok,
bool invert,
MathLib::bigint value,
ValueFlow::Value &true_value,
ValueFlow::Value &false_value)
{
if (Token::Match(tok, "==|!=|>=|<=")) {
true_value = ValueFlow::Value{tok, value};
const char* greaterThan = ">=";
const char* lessThan = "<=";
if (invert)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
false_value = ValueFlow::Value{tok, value - 1};
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
false_value = ValueFlow::Value{tok, value + 1};
} else {
false_value = ValueFlow::Value{tok, value};
}
} else {
const char* greaterThan = ">";
const char* lessThan = "<";
if (invert)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
true_value = ValueFlow::Value{tok, value + 1};
false_value = ValueFlow::Value{tok, value};
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
true_value = ValueFlow::Value{tok, value - 1};
false_value = ValueFlow::Value{tok, value};
}
}
setValueBound(true_value, tok, invert);
setValueBound(false_value, tok, !invert);
}
static bool isSaturated(MathLib::bigint value)
{
return value == std::numeric_limits<MathLib::bigint>::max() || value == std::numeric_limits<MathLib::bigint>::min();
}
const Token *parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value)
{
if (!tok->astOperand1() || !tok->astOperand2())
return nullptr;
if (tok->isComparisonOp()) {
if (tok->astOperand1()->hasKnownIntValue()) {
MathLib::bigint value = tok->astOperand1()->values().front().intvalue;
if (isSaturated(value))
return nullptr;
setConditionalValues(tok, true, value, true_value, false_value);
return tok->astOperand2();
} else if (tok->astOperand2()->hasKnownIntValue()) {
MathLib::bigint value = tok->astOperand2()->values().front().intvalue;
if (isSaturated(value))
return nullptr;
setConditionalValues(tok, false, value, true_value, false_value);
return tok->astOperand1();
}
}
return nullptr;
}
/**
* 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;
if (tok->hasKnownIntValue())
return tok;
// Is variable protected in LHS..
bool bailout = false;
visitAstNodes(tok->astOperand1(), [&](const Token *tok2) {
if (tok2->str() == ".")
return ChildrenToVisit::none;
// A variable is seen..
if (tok2 != valuetok && tok2->variable() &&
(tok2->varId() == valuetok->varId() || (!tok2->variable()->isArgument() && !tok2->hasKnownIntValue()))) {
// TODO: limit this bailout
bailout = true;
return ChildrenToVisit::done;
}
return ChildrenToVisit::op1_and_op2;
});
if (bailout)
return tok;
}
return nullptr;
}
static bool isEscapeScope(const Token* tok, TokenList * tokenlist, bool unknown = false)
{
if (!Token::simpleMatch(tok, "{"))
return false;
// TODO this search for termTok in all subscopes. It should check the end of the scope.
const Token * termTok = Token::findmatch(tok, "return|continue|break|throw|goto", tok->link());
if (termTok && termTok->scope() == tok->scope())
return true;
std::string unknownFunction;
if (tokenlist && tokenlist->getSettings()->library.isScopeNoReturn(tok->link(), &unknownFunction))
return unknownFunction.empty() || unknown;
return false;
}
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 ValueFlow::Value castValue(ValueFlow::Value value, const ValueType::Sign sign, nonneg int bit)
{
if (value.isFloatValue()) {
value.valueType = ValueFlow::Value::INT;
if (value.floatValue >= std::numeric_limits<int>::min() && value.floatValue <= std::numeric_limits<int>::max()) {
value.intvalue = value.floatValue;
} else { // don't perform UB
value.intvalue = 0;
}
}
if (bit < MathLib::bigint_bits) {
const MathLib::biguint one = 1;
value.intvalue &= (one << bit) - 1;
if (sign == ValueType::Sign::SIGNED && value.intvalue & (one << (bit - 1))) {
value.intvalue |= ~((one << bit) - 1ULL);
}
}
return value;
}
static void combineValueProperties(const ValueFlow::Value &value1, const ValueFlow::Value &value2, ValueFlow::Value *result)
{
if (value1.isKnown() && value2.isKnown())
result->setKnown();
else if (value1.isImpossible() || value2.isImpossible())
result->setImpossible();
else if (value1.isInconclusive() || value2.isInconclusive())
result->setInconclusive();
else
result->setPossible();
if (value1.isIteratorValue())
result->valueType = value1.valueType;
if (value2.isIteratorValue())
result->valueType = value2.valueType;
result->condition = value1.condition ? value1.condition : value2.condition;
result->varId = (value1.varId != 0U) ? value1.varId : value2.varId;
result->varvalue = (result->varId == value1.varId) ? value1.varvalue : value2.varvalue;
result->errorPath = (value1.errorPath.empty() ? value2 : value1).errorPath;
result->safe = value1.safe || value2.safe;
if (value1.bound == ValueFlow::Value::Bound::Point || value2.bound == ValueFlow::Value::Bound::Point) {
if (value1.bound == ValueFlow::Value::Bound::Upper || value2.bound == ValueFlow::Value::Bound::Upper)
result->bound = ValueFlow::Value::Bound::Upper;
if (value1.bound == ValueFlow::Value::Bound::Lower || value2.bound == ValueFlow::Value::Bound::Lower)
result->bound = ValueFlow::Value::Bound::Lower;
}
if (value1.path != value2.path)
result->path = -1;
else
result->path = value1.path;
}
static const Token *getCastTypeStartToken(const Token *parent)
{
// TODO: This might be a generic utility function?
if (!parent || parent->str() != "(")
return nullptr;
if (!parent->astOperand2() && Token::Match(parent,"( %name%"))
return parent->next();
if (parent->astOperand2() && Token::Match(parent->astOperand1(), "const_cast|dynamic_cast|reinterpret_cast|static_cast <"))
return parent->astOperand1()->tokAt(2);
return nullptr;
}
static bool isComputableValue(const Token* parent, const ValueFlow::Value& value)
{
const bool noninvertible = parent->isComparisonOp() || Token::Match(parent, "%|/|&|%or%");
if (noninvertible && value.isImpossible())
return false;
if (!value.isIntValue() && !value.isFloatValue() && !value.isTokValue() && !value.isIteratorValue())
return false;
if (value.isIteratorValue() && !Token::Match(parent, "+|-"))
return false;
if (value.isTokValue() && (!parent->isComparisonOp() || value.tokvalue->tokType() != Token::eString))
return false;
return true;
}
/** Set token value for cast */
static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings);
/** set ValueFlow value and perform calculations if possible */
static void setTokenValue(Token* tok, const ValueFlow::Value &value, const Settings *settings)
{
if (!tok->addValue(value))
return;
if (value.path < 0)
return;
Token *parent = tok->astParent();
if (!parent)
return;
if (value.isContainerSizeValue()) {
// .empty, .size, +"abc", +'a'
if (parent->str() == "+") {
for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) {
for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) {
if (value1.path != value2.path)
continue;
ValueFlow::Value result;
result.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
if (value1.isContainerSizeValue() && value2.isContainerSizeValue())
result.intvalue = value1.intvalue + value2.intvalue;
else if (value1.isContainerSizeValue() && value2.isTokValue() && value2.tokvalue->tokType() == Token::eString)
result.intvalue = value1.intvalue + Token::getStrLength(value2.tokvalue);
else if (value2.isContainerSizeValue() && value1.isTokValue() && value1.tokvalue->tokType() == Token::eString)
result.intvalue = Token::getStrLength(value1.tokvalue) + value2.intvalue;
else
continue;
combineValueProperties(value1, value2, &result);
setTokenValue(parent, result, settings);
}
}
}
else if (Token::Match(parent, ". %name% (") && parent->astParent() == parent->tokAt(2) && parent->astOperand1() && parent->astOperand1()->valueType()) {
const Library::Container *c = parent->astOperand1()->valueType()->container;
const Library::Container::Yield yields = c ? c->getYield(parent->strAt(1)) : Library::Container::Yield::NO_YIELD;
if (yields == Library::Container::Yield::SIZE) {
ValueFlow::Value v(value);
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(parent->astParent(), v, settings);
} else if (yields == Library::Container::Yield::EMPTY) {
ValueFlow::Value v(value);
v.intvalue = !v.intvalue;
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(parent->astParent(), v, settings);
}
}
return;
}
if (value.isLifetimeValue()) {
if (!isLifetimeBorrowed(parent, settings))
return;
if (value.lifetimeKind == ValueFlow::Value::LifetimeKind::Iterator && astIsIterator(parent)) {
setTokenValue(parent,value,settings);
} else if (astIsPointer(tok) && astIsPointer(parent) &&
(parent->isArithmeticalOp() || Token::Match(parent, "( %type%"))) {
setTokenValue(parent,value,settings);
}
return;
}
if (value.isUninitValue()) {
ValueFlow::Value pvalue = value;
if (parent->isUnaryOp("&")) {
pvalue.indirect++;
setTokenValue(parent, pvalue, settings);
} else if (Token::Match(parent, ". %var%") && parent->astOperand1() == tok) {
if (parent->originalName() == "->" && pvalue.indirect > 0)
pvalue.indirect--;
setTokenValue(parent->astOperand2(), pvalue, settings);
} else if (Token::Match(parent->astParent(), ". %var%") && parent->astParent()->astOperand1() == parent) {
if (parent->astParent()->originalName() == "->" && pvalue.indirect > 0)
pvalue.indirect--;
setTokenValue(parent->astParent()->astOperand2(), pvalue, settings);
} else if (parent->isUnaryOp("*") && pvalue.indirect > 0) {
pvalue.indirect--;
setTokenValue(parent, pvalue, settings);
}
return;
}
// cast..
if (const Token *castType = getCastTypeStartToken(parent)) {
if (astIsPointer(tok) && value.valueType == ValueFlow::Value::INT &&
Token::simpleMatch(parent->astOperand1(), "dynamic_cast"))
return;
const ValueType &valueType = ValueType::parseDecl(castType, settings);
setTokenValueCast(parent, valueType, value, settings);
}
else if (parent->str() == ":") {
setTokenValue(parent,value,settings);
}
else if (parent->str() == "?" && tok->str() == ":" && tok == parent->astOperand2() && parent->astOperand1()) {
// is condition always true/false?
if (parent->astOperand1()->hasKnownValue()) {
const ValueFlow::Value &condvalue = parent->astOperand1()->values().front();
const bool cond(condvalue.isTokValue() || (condvalue.isIntValue() && condvalue.intvalue != 0));
if (cond && !tok->astOperand1()) { // true condition, no second operator
setTokenValue(parent, condvalue, settings);
} else {
const Token *op = cond ? tok->astOperand1() : tok->astOperand2();
if (!op) // #7769 segmentation fault at setTokenValue()
return;
const std::list<ValueFlow::Value> &values = op->values();
if (std::find(values.begin(), values.end(), value) != values.end())
setTokenValue(parent, value, settings);
}
} else {
// is condition only depending on 1 variable?
int varId = 0;
bool ret = false;
visitAstNodes(parent->astOperand1(),
[&](const Token *t) {
if (t->varId()) {
if (varId > 0 || value.varId != 0U)
ret = true;
varId = t->varId();
} else if (t->str() == "(" && Token::Match(t->previous(), "%name%"))
ret = true; // function call
return ret ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2;
});
if (ret)
return;
ValueFlow::Value v(value);
v.conditional = true;
v.changeKnownToPossible();
if (varId)
v.varId = varId;
setTokenValue(parent, v, settings);
}
}
else if (parent->str() == "?" && value.isIntValue() && tok == parent->astOperand1() && value.isKnown() &&
parent->astOperand2() && parent->astOperand2()->astOperand1() && parent->astOperand2()->astOperand2()) {
const std::list<ValueFlow::Value> &values = (value.intvalue == 0
? parent->astOperand2()->astOperand2()->values()
: parent->astOperand2()->astOperand1()->values());
for (const ValueFlow::Value &v : values)
setTokenValue(parent, v, settings);
}
// Calculations..
else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp) || (parent->tokType() == Token::eLogicalOp)) &&
parent->astOperand1() &&
parent->astOperand2()) {
const bool noninvertible = parent->isComparisonOp() || Token::Match(parent, "%|/|&|%or%");
// Skip operators with impossible values that are not invertible
if (noninvertible && value.isImpossible())
return;
// known result when a operand is 0.
if (Token::Match(parent, "[&*]") && value.isKnown() && value.isIntValue() && value.intvalue==0) {
setTokenValue(parent, value, settings);
return;
}
// known result when a operand is true.
if (Token::simpleMatch(parent, "&&") && value.isKnown() && value.isIntValue() && value.intvalue==0) {
setTokenValue(parent, value, settings);
return;
}
// known result when a operand is false.
if (Token::simpleMatch(parent, "||") && value.isKnown() && value.isIntValue() && value.intvalue!=0) {
setTokenValue(parent, value, settings);
return;
}
for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) {
if (!isComputableValue(parent, value1))
continue;
for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) {
if (value1.path != value2.path)
continue;
if (!isComputableValue(parent, value2))
continue;
if (value1.isIteratorValue() && value2.isIteratorValue())
continue;
if (value1.isKnown() || value2.isKnown() || value1.varId == 0U || value2.varId == 0U ||
(value1.varId == value2.varId && value1.varvalue == value2.varvalue && value1.isIntValue() &&
value2.isIntValue())) {
ValueFlow::Value result(0);
combineValueProperties(value1, value2, &result);
const float floatValue1 = value1.isIntValue() ? value1.intvalue : value1.floatValue;
const float floatValue2 = value2.isIntValue() ? value2.intvalue : value2.floatValue;
switch (parent->str()[0]) {
case '+':
if (value1.isTokValue() || value2.isTokValue())
break;
if (value1.isFloatValue() || value2.isFloatValue()) {
result.valueType = ValueFlow::Value::FLOAT;
result.floatValue = floatValue1 + floatValue2;
} else {
result.intvalue = value1.intvalue + value2.intvalue;
}
setTokenValue(parent, result, settings);
break;
case '-':
if (value1.isTokValue() || value2.isTokValue())
break;
if (value1.isFloatValue() || value2.isFloatValue()) {
result.valueType = ValueFlow::Value::FLOAT;
result.floatValue = floatValue1 - floatValue2;
} else {
result.intvalue = value1.intvalue - value2.intvalue;
}
// If the bound comes from the second value then invert the bound
if (value2.bound == result.bound && value2.bound != ValueFlow::Value::Bound::Point)
result.invertBound();
setTokenValue(parent, result, settings);
break;
case '*':
if (value1.isTokValue() || value2.isTokValue())
break;
if (value1.isFloatValue() || value2.isFloatValue()) {
result.valueType = ValueFlow::Value::FLOAT;
result.floatValue = floatValue1 * floatValue2;
} else {
result.intvalue = value1.intvalue * value2.intvalue;
}
setTokenValue(parent, result, settings);
break;
case '/':
if (value1.isTokValue() || value2.isTokValue() || value2.intvalue == 0)
break;
if (value1.isFloatValue() || value2.isFloatValue()) {
result.valueType = ValueFlow::Value::FLOAT;
result.floatValue = floatValue1 / floatValue2;
} else {
result.intvalue = value1.intvalue / value2.intvalue;
}
setTokenValue(parent, result, settings);
break;
case '%':
if (!value1.isIntValue() || !value2.isIntValue())
break;
if (value2.intvalue == 0)
break;
result.intvalue = value1.intvalue % value2.intvalue;
setTokenValue(parent, result, settings);
break;
case '=':
if (parent->str() == "==") {
if ((value1.isIntValue() && value2.isTokValue()) ||
(value1.isTokValue() && value2.isIntValue())) {
result.intvalue = 0;
setTokenValue(parent, result, settings);
} else if (value1.isIntValue() && value2.isIntValue()) {
result.intvalue = value1.intvalue == value2.intvalue;
setTokenValue(parent, result, settings);
}
}
break;
case '!':
if (parent->str() == "!=") {
if ((value1.isIntValue() && value2.isTokValue()) ||
(value1.isTokValue() && value2.isIntValue())) {
result.intvalue = 1;
setTokenValue(parent, result, settings);
} else if (value1.isIntValue() && value2.isIntValue()) {
result.intvalue = value1.intvalue != value2.intvalue;
setTokenValue(parent, result, settings);
}
}
break;
case '>': {
const bool f = value1.isFloatValue() || value2.isFloatValue();
if (!f && !value1.isIntValue() && !value2.isIntValue())
break;
if (parent->str() == ">")
result.intvalue = f ? (floatValue1 > floatValue2) : (value1.intvalue > value2.intvalue);
else if (parent->str() == ">=")
result.intvalue = f ? (floatValue1 >= floatValue2) : (value1.intvalue >= value2.intvalue);
else if (!f && parent->str() == ">>" && value1.intvalue >= 0 && value2.intvalue >= 0 && value2.intvalue < MathLib::bigint_bits)
result.intvalue = value1.intvalue >> value2.intvalue;
else
break;
setTokenValue(parent, result, settings);
break;
}
case '<': {
const bool f = value1.isFloatValue() || value2.isFloatValue();
if (!f && !value1.isIntValue() && !value2.isIntValue())
break;
if (parent->str() == "<")
result.intvalue = f ? (floatValue1 < floatValue2) : (value1.intvalue < value2.intvalue);
else if (parent->str() == "<=")
result.intvalue = f ? (floatValue1 <= floatValue2) : (value1.intvalue <= value2.intvalue);
else if (!f && parent->str() == "<<" && value1.intvalue >= 0 && value2.intvalue >= 0 && value2.intvalue < MathLib::bigint_bits)
result.intvalue = value1.intvalue << value2.intvalue;
else
break;
setTokenValue(parent, result, settings);
break;
}
case '&':
if (!value1.isIntValue() || !value2.isIntValue())
break;
if (parent->str() == "&")
result.intvalue = value1.intvalue & value2.intvalue;
else
result.intvalue = value1.intvalue && value2.intvalue;
setTokenValue(parent, result, settings);
break;
case '|':
if (!value1.isIntValue() || !value2.isIntValue())
break;
if (parent->str() == "|")
result.intvalue = value1.intvalue | value2.intvalue;
else
result.intvalue = value1.intvalue || value2.intvalue;
setTokenValue(parent, result, settings);
break;
case '^':
if (!value1.isIntValue() || !value2.isIntValue())
break;
result.intvalue = value1.intvalue ^ value2.intvalue;
setTokenValue(parent, result, settings);
break;
default:
// unhandled operator, do nothing
break;
}
}
}
}
}
// !
else if (parent->str() == "!") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue())
continue;
ValueFlow::Value v(val);
v.intvalue = !v.intvalue;
setTokenValue(parent, v, settings);
}
}
// ~
else if (parent->str() == "~") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue())
continue;
ValueFlow::Value v(val);
v.intvalue = ~v.intvalue;
int bits = 0;
if (settings &&
tok->valueType() &&
tok->valueType()->sign == ValueType::Sign::UNSIGNED &&
tok->valueType()->pointer == 0) {
if (tok->valueType()->type == ValueType::Type::INT)
bits = settings->int_bit;
else if (tok->valueType()->type == ValueType::Type::LONG)
bits = settings->long_bit;
}
if (bits > 0 && bits < MathLib::bigint_bits)
v.intvalue &= (((MathLib::biguint)1)<<bits) - 1;
setTokenValue(parent, v, settings);
}
}
// unary minus
else if (parent->isUnaryOp("-")) {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue())
continue;
ValueFlow::Value v(val);
if (v.isIntValue())
v.intvalue = -v.intvalue;
else
v.floatValue = -v.floatValue;
v.invertBound();
setTokenValue(parent, v, settings);
}
}
// increment
else if (parent->str() == "++") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue())
continue;
ValueFlow::Value v(val);
if (parent == tok->previous()) {
if (v.isIntValue())
v.intvalue = v.intvalue + 1;
else
v.floatValue = v.floatValue + 1.0;
}
setTokenValue(parent, v, settings);
}
}
// decrement
else if (parent->str() == "--") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue())
continue;
ValueFlow::Value v(val);
if (parent == tok->previous()) {
if (v.isIntValue())
v.intvalue = v.intvalue - 1;
else
v.floatValue = v.floatValue - 1.0;
}
setTokenValue(parent, v, settings);
}
}
// Array element
else if (parent->str() == "[" && parent->isBinaryOp()) {
for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) {
if (!value1.isTokValue())
continue;
for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) {
if (!value2.isIntValue())
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.setInconclusive(value1.isInconclusive() | value2.isInconclusive());
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, settings);
} else if (index >= 0 && index < s.size()) {
result.intvalue = s[index];
setTokenValue(parent, result, settings);
}
} 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, settings);
}
}
}
}
}
}
else if (Token::Match(parent, ":: %name%") && parent->astOperand2() == tok) {
setTokenValue(parent, value, settings);
}
}
static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings)
{
if (valueType.pointer)
setTokenValue(parent,value,settings);
else if (valueType.type == ValueType::Type::CHAR)
setTokenValue(parent, castValue(value, valueType.sign, settings->char_bit), settings);
else if (valueType.type == ValueType::Type::SHORT)
setTokenValue(parent, castValue(value, valueType.sign, settings->short_bit), settings);
else if (valueType.type == ValueType::Type::INT)
setTokenValue(parent, castValue(value, valueType.sign, settings->int_bit), settings);
else if (valueType.type == ValueType::Type::LONG)
setTokenValue(parent, castValue(value, valueType.sign, settings->long_bit), settings);
else if (valueType.type == ValueType::Type::LONGLONG)
setTokenValue(parent, castValue(value, valueType.sign, settings->long_long_bit), settings);
else if (value.isIntValue()) {
const long long charMax = settings->signedCharMax();
const long long charMin = settings->signedCharMin();
if (charMin <= value.intvalue && value.intvalue <= charMax) {
// unknown type, but value is small so there should be no truncation etc
setTokenValue(parent,value,settings);
}
}
}
static nonneg int getSizeOfType(const Token *typeTok, const Settings *settings)
{
const ValueType &valueType = ValueType::parseDecl(typeTok, settings);
if (valueType.pointer > 0)
return settings->sizeof_pointer;
if (valueType.type == ValueType::Type::BOOL || valueType.type == ValueType::Type::CHAR)
return 1;
if (valueType.type == ValueType::Type::SHORT)
return settings->sizeof_short;
if (valueType.type == ValueType::Type::INT)
return settings->sizeof_int;
if (valueType.type == ValueType::Type::LONG)
return settings->sizeof_long;
if (valueType.type == ValueType::Type::LONGLONG)
return settings->sizeof_long_long;
if (valueType.type == ValueType::Type::WCHAR_T)
return settings->sizeof_wchar_t;
return 0;
}
size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings *settings)
{
if (vt.pointer)
return settings->sizeof_pointer;
if (vt.type == ValueType::Type::CHAR)
return 1;
if (vt.type == ValueType::Type::SHORT)
return settings->sizeof_short;
if (vt.type == ValueType::Type::WCHAR_T)
return settings->sizeof_wchar_t;
if (vt.type == ValueType::Type::INT)
return settings->sizeof_int;
if (vt.type == ValueType::Type::LONG)
return settings->sizeof_long;
if (vt.type == ValueType::Type::LONGLONG)
return settings->sizeof_long_long;
if (vt.type == ValueType::Type::FLOAT)
return settings->sizeof_float;
if (vt.type == ValueType::Type::DOUBLE)
return settings->sizeof_double;
return 0;
}
// Handle various constants..
static Token * valueFlowSetConstantValue(Token *tok, const Settings *settings, bool cpp)
{
if ((tok->isNumber() && MathLib::isInt(tok->str())) || (tok->tokType() == Token::eChar)) {
ValueFlow::Value value(MathLib::toLongNumber(tok->str()));
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, settings);
} else if (tok->isNumber() && MathLib::isFloat(tok->str())) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::FLOAT;
value.floatValue = MathLib::toDoubleNumber(tok->str());
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, settings);
} else if (tok->enumerator() && tok->enumerator()->value_known) {
ValueFlow::Value value(tok->enumerator()->value);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, settings);
} else if (tok->str() == "NULL" || (cpp && tok->str() == "nullptr")) {
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, settings);
} else if (Token::simpleMatch(tok, "sizeof (")) {
const Token *tok2 = tok->tokAt(2);
// skip over tokens to find variable or type
while (Token::Match(tok2, "%name% ::|.|[")) {
if (tok2->next()->str() == "[")
tok2 = tok2->linkAt(1)->next();
else
tok2 = tok2->tokAt(2);
}
if (Token::simpleMatch(tok, "sizeof ( *")) {
const ValueType *vt = tok->tokAt(2)->valueType();
const size_t sz = vt ? ValueFlow::getSizeOf(*vt, settings) : 0;
if (sz > 0) {
ValueFlow::Value value(sz);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok->next(), value, settings);
}
} else if (tok2->enumerator() && tok2->enumerator()->scope) {
long long size = settings->sizeof_int;
const Token * type = tok2->enumerator()->scope->enumType;
if (type) {
size = getSizeOfType(type, settings);
if (size == 0)
tok->linkAt(1);
}
ValueFlow::Value value(size);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), value, settings);
} else if (tok2->type() && tok2->type()->isEnumType()) {
long long size = settings->sizeof_int;
if (tok2->type()->classScope) {
const Token * type = tok2->type()->classScope->enumType;
if (type) {
size = getSizeOfType(type, settings);
}
}
ValueFlow::Value value(size);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), value, settings);
} else if (Token::Match(tok, "sizeof ( %var% ) / sizeof (") && tok->next()->astParent() == tok->tokAt(4)) {
// Get number of elements in array
const Token *sz1 = tok->tokAt(2);
const Token *sz2 = tok->tokAt(7);
const int varid1 = sz1->varId();
if (varid1 &&
sz1->variable() &&
sz1->variable()->isArray() &&
!sz1->variable()->dimensions().empty() &&
sz1->variable()->dimensionKnown(0) &&
(Token::Match(sz2, "* %varid% )", varid1) || Token::Match(sz2, "%varid% [ 0 ] )", varid1))) {
ValueFlow::Value value(sz1->variable()->dimension(0));
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok->tokAt(4), value, settings);
}
} else if (Token::Match(tok2, "%var% )")) {
const Variable *var = tok2->variable();
// only look for single token types (no pointers or references yet)
if (var && var->typeStartToken() == var->typeEndToken()) {
// find the size of the type
size_t size = 0;
if (var->isEnumType()) {
size = settings->sizeof_int;
if (var->type()->classScope && var->type()->classScope->enumType)
size = getSizeOfType(var->type()->classScope->enumType, settings);
} else if (var->valueType()) {
size = ValueFlow::getSizeOf(*var->valueType(), settings);
} else if (!var->type()) {
size = getSizeOfType(var->typeStartToken(), settings);
}
// find the number of elements
size_t count = 1;
for (size_t i = 0; i < var->dimensions().size(); ++i) {
if (var->dimensionKnown(i))
count *= var->dimension(i);
else
count = 0;
}
if (size && count > 0) {
ValueFlow::Value value(count * size);
if (settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), value, settings);
}
}
} else if (tok2->tokType() == Token::eString) {
size_t sz = Token::getStrSize(tok2, settings);
if (sz > 0) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(const_cast<Token *>(tok->next()), value, settings);
}
} else if (tok2->tokType() == Token::eChar) {
nonneg int sz = 0;
if (cpp && settings->standards.cpp >= Standards::CPP20 && tok2->isUtf8())
sz = 1;
else if (tok2->isUtf16())
sz = 2;
else if (tok2->isUtf32())
sz = 4;
else if (tok2->isLong())
sz = settings->sizeof_wchar_t;
else if ((tok2->isCChar() && !cpp) || (tok2->isCMultiChar()))
sz = settings->sizeof_int;
else
sz = 1;
if (sz > 0) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(tok->next(), value, settings);
}
} else if (!tok2->type()) {
const ValueType &vt = ValueType::parseDecl(tok2,settings);
const size_t sz = ValueFlow::getSizeOf(vt, settings);
if (sz > 0) {
ValueFlow::Value value(sz);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok->next(), value, settings);
}
}
// 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(), tokenlist->isCPP());
}
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");
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, tokenlist->getSettings());
} else if (Token::Match(tok, "[(,] NULL [,)]")) {
// NULL function parameters are not simplified in the
// normal tokenlist
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok->next(), value, tokenlist->getSettings());
}
}
}
}
static void valueFlowString(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->tokType() == Token::eString) {
ValueFlow::Value strvalue;
strvalue.valueType = ValueFlow::Value::TOK;
strvalue.tokvalue = tok;
strvalue.setKnown();
setTokenValue(tok, strvalue, tokenlist->getSettings());
}
}
}
static void valueFlowArray(TokenList *tokenlist)
{
std::map<int, const Token *> constantArrays;
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->varId() > 0U) {
// array
const std::map<int, const Token *>::const_iterator it = constantArrays.find(tok->varId());
if (it != constantArrays.end()) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::TOK;
value.tokvalue = it->second;
value.setKnown();
setTokenValue(tok, value, tokenlist->getSettings());
}
// 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.valueType = ValueFlow::Value::TOK;
value.tokvalue = tok;
value.setKnown();
setTokenValue(tok, value, tokenlist->getSettings());
}
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 bool isNonZero(const Token *tok)
{
return tok && (!tok->hasKnownIntValue() || tok->values().front().intvalue != 0);
}
static const Token *getOtherOperand(const Token *tok)
{
if (!tok)
return nullptr;
if (!tok->astParent())
return nullptr;
if (tok->astParent()->astOperand1() != tok)
return tok->astParent()->astOperand1();
if (tok->astParent()->astOperand2() != tok)
return tok->astParent()->astOperand2();
return nullptr;
}
static void valueFlowArrayBool(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
const Variable *var = nullptr;
bool known = false;
std::list<ValueFlow::Value>::const_iterator val =
std::find_if(tok->values().begin(), tok->values().end(), std::mem_fn(&ValueFlow::Value::isTokValue));
if (val == tok->values().end()) {
var = tok->variable();
known = true;
} else {
var = val->tokvalue->variable();
known = val->isKnown();
}
if (!var)
continue;
if (!var->isArray() || var->isArgument() || var->isStlType())
continue;
if (isNonZero(getOtherOperand(tok)) && Token::Match(tok->astParent(), "%comp%"))
continue;
// TODO: Check for function argument
if ((astIsBool(tok->astParent()) && !Token::Match(tok->astParent(), "(|%name%")) ||
(tok->astParent() && Token::Match(tok->astParent()->previous(), "if|while|for ("))) {
ValueFlow::Value value{1};
if (known)
value.setKnown();
setTokenValue(tok, value, tokenlist->getSettings());
}
}
}
static void valueFlowPointerAlias(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
// not address of
if (!tok->isUnaryOp("&"))
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.valueType = ValueFlow::Value::TOK;
value.tokvalue = tok;
setTokenValue(tok, value, tokenlist->getSettings());
}
}
static void valueFlowPointerAliasDeref(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->isUnaryOp("*"))
continue;
if (!astIsPointer(tok->astOperand1()))
continue;
const Token* lifeTok = nullptr;
ErrorPath errorPath;
for (const ValueFlow::Value& v:tok->astOperand1()->values()) {
if (!v.isLocalLifetimeValue())
continue;
lifeTok = v.tokvalue;
errorPath = v.errorPath;
}
if (!lifeTok)
continue;
if (lifeTok->varId() == 0)
continue;
const Variable * var = lifeTok->variable();
if (!var)
continue;
if (!var->isConst() && isVariableChanged(lifeTok->next(), tok, lifeTok->varId(), !var->isLocal(), tokenlist->getSettings(), tokenlist->isCPP()))
continue;
for (const ValueFlow::Value& v:lifeTok->values()) {
// TODO: Move container size values to generic forward
// Forward uninit values since not all values can be forwarded directly
if (!(v.isContainerSizeValue() || v.isUninitValue()))
continue;
ValueFlow::Value value = v;
value.errorPath.insert(value.errorPath.begin(), errorPath.begin(), errorPath.end());
setTokenValue(tok, value, tokenlist->getSettings());
}
}
}
static void valueFlowBitAnd(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->str() != "&")
continue;
if (tok->hasKnownValue())
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 <= (MathLib::bigint_bits - 2) && ((((MathLib::bigint)1) << bit) < number))
++bit;
if ((((MathLib::bigint)1) << bit) == number) {
setTokenValue(tok, ValueFlow::Value(0), tokenlist->getSettings());
setTokenValue(tok, ValueFlow::Value(number), tokenlist->getSettings());
}
}
}
static void valueFlowSameExpressions(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->hasKnownValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
if (tok->astOperand1()->isLiteral() || tok->astOperand2()->isLiteral())
continue;
if (!astIsIntegral(tok->astOperand1(), false) && !astIsIntegral(tok->astOperand2(), false))
continue;
ValueFlow::Value val;
if (Token::Match(tok, "==|>=|<=|/")) {
val = ValueFlow::Value(1);
val.setKnown();
}
if (Token::Match(tok, "!=|>|<|%|-")) {
val = ValueFlow::Value(0);
val.setKnown();
}
if (!val.isKnown())
continue;
if (isSameExpression(tokenlist->isCPP(), false, tok->astOperand1(), tok->astOperand2(), tokenlist->getSettings()->library, true, true, &val.errorPath)) {
setTokenValue(tok, val, tokenlist->getSettings());
}
}
}
static void valueFlowTerminatingCondition(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
const bool cpp = symboldatabase->isCPP();
typedef std::pair<const Token*, const Scope*> Condition;
for (const Scope * scope : symboldatabase->functionScopes) {
bool skipFunction = false;
std::vector<Condition> conds;
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (tok->isIncompleteVar()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "Skipping function due to incomplete variable " + tok->str());
skipFunction = true;
break;
}
if (!Token::simpleMatch(tok, "if ("))
continue;
// Skip known values
if (tok->next()->hasKnownValue())
continue;
const Token * condTok = tok->next();
if (!Token::simpleMatch(condTok->link(), ") {"))
continue;
const Token * blockTok = condTok->link()->tokAt(1);
// Check if the block terminates early
if (!isEscapeScope(blockTok, tokenlist))
continue;
// Check if any variables are modified in scope
bool bail = false;
for (const Token * tok2=condTok->next(); tok2 != condTok->link(); tok2 = tok2->next()) {
const Variable * var = tok2->variable();
if (!var)
continue;
if (!var->scope())
continue;
const Token * endToken = var->scope()->bodyEnd;
if (!var->isLocal() && !var->isConst() && !var->isArgument()) {
bail = true;
break;
}
if (var->isStatic() && !var->isConst()) {
bail = true;
break;
}
if (!var->isConst() && var->declEndToken() && isVariableChanged(var->declEndToken()->next(), endToken, tok2->varId(), false, settings, cpp)) {
bail = true;
break;
}
}
if (bail)
continue;
// TODO: Handle multiple conditions
if (Token::Match(condTok->astOperand2(), "%oror%|%or%|&|&&"))
continue;
const Scope * condScope = nullptr;
for (const Scope * parent = condTok->scope(); parent; parent = parent->nestedIn) {
if (parent->type == Scope::eIf ||
parent->type == Scope::eWhile ||
parent->type == Scope::eSwitch) {
condScope = parent;
break;
}
}
conds.emplace_back(condTok->astOperand2(), condScope);
}
if (skipFunction)
break;
for (Condition cond:conds) {
if (!cond.first)
continue;
Token *const startToken = cond.first->findExpressionStartEndTokens().second->next();
for (Token* tok = startToken; tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "%comp%"))
continue;
// Skip known values
if (tok->hasKnownValue())
continue;
if (cond.second) {
bool bail = true;
for (const Scope * parent = tok->scope()->nestedIn; parent; parent = parent->nestedIn) {
if (parent == cond.second) {
bail = false;
break;
}
}
if (bail)
continue;
}
ErrorPath errorPath;
if (isOppositeCond(true, cpp, tok, cond.first, settings->library, true, true, &errorPath)) {
ValueFlow::Value val(1);
val.setKnown();
val.condition = cond.first;
val.errorPath = errorPath;
val.errorPath.emplace_back(cond.first, "Assuming condition '" + cond.first->expressionString() + "' is false");
setTokenValue(tok, val, tokenlist->getSettings());
} else if (isSameExpression(cpp, true, tok, cond.first, settings->library, true, true, &errorPath)) {
ValueFlow::Value val(0);
val.setKnown();
val.condition = cond.first;
val.errorPath = errorPath;
val.errorPath.emplace_back(cond.first, "Assuming condition '" + cond.first->expressionString() + "' is false");
setTokenValue(tok, val, tokenlist->getSettings());
}
}
}
}
}
static bool getExpressionRange(const Token *expr, MathLib::bigint *minvalue, MathLib::bigint *maxvalue)
{
if (expr->hasKnownIntValue()) {
if (minvalue)
*minvalue = expr->values().front().intvalue;
if (maxvalue)
*maxvalue = expr->values().front().intvalue;
return true;
}
if (expr->str() == "&" && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint vals[4];
bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
bool rhsHasKnownRange = getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]);
if (!lhsHasKnownRange && !rhsHasKnownRange)
return false;
if (!lhsHasKnownRange || !rhsHasKnownRange) {
if (minvalue)
*minvalue = lhsHasKnownRange ? vals[0] : vals[2];
if (maxvalue)
*maxvalue = lhsHasKnownRange ? vals[1] : vals[3];
} else {
if (minvalue)
*minvalue = vals[0] & vals[2];
if (maxvalue)
*maxvalue = vals[1] & vals[3];
}
return true;
}
if (expr->str() == "%" && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint vals[4];
if (!getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]))
return false;
if (vals[2] <= 0)
return false;
bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
if (lhsHasKnownRange && vals[0] < 0)
return false;
// If lhs has unknown value, it must be unsigned
if (!lhsHasKnownRange && (!expr->astOperand1()->valueType() || expr->astOperand1()->valueType()->sign != ValueType::Sign::UNSIGNED))
return false;
if (minvalue)
*minvalue = 0;
if (maxvalue)
*maxvalue = vals[3] - 1;
return true;
}
return false;
}
static void valueFlowRightShift(TokenList *tokenList, const Settings* settings)
{
for (Token *tok = tokenList->front(); tok; tok = tok->next()) {
if (tok->str() != ">>")
continue;
if (tok->hasKnownValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
if (!tok->astOperand2()->hasKnownValue())
continue;
const MathLib::bigint rhsvalue = tok->astOperand2()->values().front().intvalue;
if (rhsvalue < 0)
continue;
if (!tok->astOperand1()->valueType() || !tok->astOperand1()->valueType()->isIntegral())
continue;
if (!tok->astOperand2()->valueType() || !tok->astOperand2()->valueType()->isIntegral())
continue;
MathLib::bigint lhsmax=0;
if (!getExpressionRange(tok->astOperand1(), nullptr, &lhsmax))
continue;
if (lhsmax < 0)
continue;
int lhsbits;
if ((tok->astOperand1()->valueType()->type == ValueType::Type::CHAR) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::SHORT) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::WCHAR_T) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::BOOL) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::INT))
lhsbits = settings->int_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONG)
lhsbits = settings->long_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONGLONG)
lhsbits = settings->long_long_bit;
else
continue;
if (rhsvalue >= lhsbits || rhsvalue >= MathLib::bigint_bits || (1ULL << rhsvalue) <= lhsmax)
continue;
ValueFlow::Value val(0);
val.setKnown();
setTokenValue(tok, val, tokenList->getSettings());
}
}
static void valueFlowOppositeCondition(SymbolDatabase *symboldatabase, const Settings *settings)
{
for (const Scope &scope : symboldatabase->scopeList) {
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;
Token *ifOpenBraceTok = tok2->tokAt(4);
Token *cond2 = ifOpenBraceTok->astOperand2();
if (!cond2 || !cond2->isComparisonOp())
continue;
if (isOppositeCond(true, cpp, cond1, cond2, settings->library, true, true)) {
ValueFlow::Value value(1);
value.setKnown();
setTokenValue(cond2, value, settings);
}
tok2 = ifOpenBraceTok->link();
}
}
}
static void valueFlowGlobalConstVar(TokenList* tokenList, const Settings *settings)
{
// Get variable values...
std::map<const Variable*, ValueFlow::Value> vars;
for (const Token* tok = tokenList->front(); tok; tok = tok->next()) {
if (!tok->variable())
continue;
// Initialization...
if (tok == tok->variable()->nameToken() &&
!tok->variable()->isVolatile() &&
!tok->variable()->isArgument() &&
tok->variable()->isConst() &&
tok->valueType() &&
tok->valueType()->isIntegral() &&
tok->valueType()->pointer == 0 &&
tok->valueType()->constness == 1 &&
Token::Match(tok, "%name% =") &&
tok->next()->astOperand2() &&
tok->next()->astOperand2()->hasKnownIntValue()) {
vars[tok->variable()] = tok->next()->astOperand2()->values().front();
}
}
// Set values..
for (Token* tok = tokenList->front(); tok; tok = tok->next()) {
if (!tok->variable())
continue;
std::map<const Variable*, ValueFlow::Value>::const_iterator var = vars.find(tok->variable());
if (var == vars.end())
continue;
setTokenValue(tok, var->second, settings);
}
}
static void valueFlowGlobalStaticVar(TokenList *tokenList, const Settings *settings)
{
// Get variable values...
std::map<const Variable *, ValueFlow::Value> vars;
for (const Token *tok = tokenList->front(); tok; tok = tok->next()) {
if (!tok->variable())
continue;
// Initialization...
if (tok == tok->variable()->nameToken() &&
tok->variable()->isStatic() &&
!tok->variable()->isConst() &&
tok->valueType() &&
tok->valueType()->isIntegral() &&
tok->valueType()->pointer == 0 &&
tok->valueType()->constness == 0 &&
Token::Match(tok, "%name% =") &&
tok->next()->astOperand2() &&
tok->next()->astOperand2()->hasKnownIntValue()) {
vars[tok->variable()] = tok->next()->astOperand2()->values().front();
} else {
// If variable is written anywhere in TU then remove it from vars
if (!tok->astParent())
continue;
if (Token::Match(tok->astParent(), "++|--|&") && !tok->astParent()->astOperand2())
vars.erase(tok->variable());
else if (tok->astParent()->isAssignmentOp()) {
if (tok == tok->astParent()->astOperand1())
vars.erase(tok->variable());
else if (tokenList->isCPP() && Token::Match(tok->astParent()->tokAt(-2), "& %name% ="))
vars.erase(tok->variable());
} else if (isLikelyStreamRead(tokenList->isCPP(), tok->astParent())) {
vars.erase(tok->variable());
} else if (Token::Match(tok->astParent(), "[(,]"))
vars.erase(tok->variable());
}
}
// Set values..
for (Token *tok = tokenList->front(); tok; tok = tok->next()) {
if (!tok->variable())
continue;
std::map<const Variable *, ValueFlow::Value>::const_iterator var = vars.find(tok->variable());
if (var == vars.end())
continue;
setTokenValue(tok, var->second, settings);
}
}
static void valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
std::list<ValueFlow::Value> values,
TokenList* const tokenlist,
const Settings* const settings);
// Old deprecated version
static void valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
const bool constValue,
const bool subFunction,
TokenList* const tokenlist,
ErrorLogger* const errorLogger,
const Settings* settings);
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 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 || tok2->scope()->type == Scope::ScopeType::eLambda))) {
break;
}
if (tok2->varId() == varid) {
if (tok2->hasKnownValue())
break;
// bailout: assignment
if (Token::Match(tok2->previous(), "!!* %name% =")) {
Token* assignTok = const_cast<Token*>(tok2->next()->astOperand2());
if (!assignTok->hasKnownValue()) {
setTokenValue(assignTok, val, settings);
const std::string info = "Assignment from '" + assignTok->expressionString() + "'";
val.errorPath.emplace_back(assignTok, info);
std::list<ValueFlow::Value> values = {val};
if (val2.condition) {
val2.errorPath.emplace_back(assignTok, info);
setTokenValue(assignTok, val2, settings);
values.push_back(val2);
}
const Token* startForwardToken = nextAfterAstRightmostLeaf(tok2->next());
const Token* endForwardToken = tok->scope() ? tok->scope()->bodyEnd : tok;
valueFlowForward(const_cast<Token*>(startForwardToken),
endForwardToken,
assignTok,
values,
false,
false,
tokenlist,
errorLogger,
settings);
// Only reverse analysis supported with variables
if (assignTok->varId() > 0)
valueFlowReverse(tokenlist, tok2->previous(), assignTok, val, val2, errorLogger, settings);
}
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str());
break;
}
// increment/decrement
int inc = 0;
if (Token::Match(tok2->previous(), "[;{}] %name% ++|-- ;"))
inc = (tok2->strAt(1)=="++") ? -1 : 1;
else if (Token::Match(tok2->tokAt(-2), "[;{}] ++|-- %name% ;"))
inc = (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;
}
if (inc != 0) {
val.intvalue += inc;
const std::string info(tok2->str() + " is " + std::string(inc==1 ? "decremented" : "incremented") + ", before this " + (inc==1?"decrement":"increment") + " the value is " + val.infoString());
val.errorPath.emplace_back(tok2, info);
}
// compound assignment
if (Token::Match(tok2->previous(), "[;{}] %var% %assign%") && tok2->next()->str() != "=") {
const Token * const assignToken = tok2->next();
const Token * const rhsToken = assignToken->astOperand2();
if (!rhsToken || !rhsToken->hasKnownIntValue()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "compound assignment, rhs value is not known");
break;
}
const MathLib::bigint rhsValue = rhsToken->values().front().intvalue;
if (assignToken->str() == "+=")
val.intvalue -= rhsValue;
else if (assignToken->str() == "-=")
val.intvalue += rhsValue;
else if (assignToken->str() == "*=" && rhsValue != 0)
val.intvalue /= rhsValue;
else {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "compound assignment " + tok2->str());
break;
}
const std::string info("Compound assignment '" + assignToken->str() + "', before assignment value is " + val.infoString());
val.errorPath.emplace_back(tok2, info);
}
// 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 (isVariableChangedByFunctionCall(tok2, std::max(val.indirect, val2.indirect), settings, &inconclusive)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction");
break;
}
// Impossible values can't be inconclusive
if (val.isImpossible() || val2.isImpossible())
break;
val.setInconclusive(inconclusive);
val2.setInconclusive(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;
}
// do-while condition, break in the loop body
{
const Token *parent = tok2->astParent();
while (parent && !Token::simpleMatch(parent->previous(), "while ("))
parent = parent->astParent();
if (parent && Token::simpleMatch(parent->tokAt(-2), "} while (") && Token::simpleMatch(parent->linkAt(-2)->previous(), "do {")) {
bool breakBailout = false;
for (const Token *iftok = parent->linkAt(-2); iftok != parent; iftok = iftok->next()) {
if (!Token::simpleMatch(iftok, "if ("))
continue;
if (!Token::simpleMatch(iftok->linkAt(1), ") { break"))
continue;
ProgramMemory programMemory;
programMemory.setIntValue(varid, num);
if (conditionIsTrue(iftok->next()->astOperand2(), programMemory)) {
breakBailout = true;
break;
}
}
if (breakBailout) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok2,
"no simplification of " + tok2->str() + " in do-while condition since there is a break in the loop body");
break;
}
}
}
setTokenValue(tok2, val, settings);
if (val2.condition)
setTokenValue(tok2,val2, settings);
if (tok2 == var->nameToken())
break;
}
// skip sizeof etc..
if (tok2->str() == ")" && Token::Match(tok2->link()->previous(), "sizeof|typeof|typeid ("))
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* condTok = getCondTokFromEnd(tok2);
// Evaluate condition of for and while loops first
if (condTok && condTok->astTop() && Token::Match(condTok->astTop()->previous(), "for|while (")) {
const Token* startTok = nullptr;
const Token* endTok = nullptr;
std::tie(startTok, endTok) = condTok->findExpressionStartEndTokens();
if (!isVariableChanged(startTok, endTok, varid, false, settings, true)) {
std::list<ValueFlow::Value> values = {val};
if (val2.condition) {
values.push_back(val2);
}
const Token *expr = Token::findmatch(tok2, "%varid%", varid);
valueFlowForward(const_cast<Token*>(startTok),
endTok,
expr,
values,
false,
false,
tokenlist,
errorLogger,
settings);
}
}
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();
if (Token::simpleMatch(tok2->previous(), ") {") && Token::Match(tok2->previous()->link()->previous(), "for|while ("))
tok2 = tok2->previous()->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,var->isGlobal(),settings, tokenlist->isCPP())) {
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;
}
}
if (Token::Match(tok2, "%name% (") && !Token::simpleMatch(tok2->linkAt(1), ") {")) {
// bailout: global non-const variables
if (!(var->isLocal() || var->isArgument()) && !var->isConst()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "global variable " + var->name());
return;
}
}
}
}
static bool isConditionKnown(const Token* tok, bool then)
{
const char* op = "||";
if (then)
op = "&&";
const Token* parent = tok->astParent();
while (parent && (parent->str() == op || parent->str() == "!"))
parent = parent->astParent();
return (parent && parent->str() == "(");
}
static void valueFlowBeforeCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope * scope : symboldatabase->functionScopes) {
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
MathLib::bigint num = 0;
const Token *vartok = nullptr;
if (tok->isComparisonOp() && tok->astOperand1() && tok->astOperand2()) {
if (tok->astOperand1()->isName() && tok->astOperand2()->hasKnownIntValue()) {
vartok = tok->astOperand1();
num = tok->astOperand2()->values().front().intvalue;
} else if (tok->astOperand1()->hasKnownIntValue() && tok->astOperand2()->isName()) {
vartok = tok->astOperand2();
num = tok->astOperand1()->values().front().intvalue;
} 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 (Token::Match(tok, "[!?]") && Token::Match(tok->astOperand1(), "%name%")) {
vartok = tok->astOperand1();
num = 0;
} else {
continue;
}
int varid = vartok->varId();
const Variable * const var = vartok->variable();
if (varid == 0U || !var)
continue;
if (tok->str() == "?" && tok->isExpandedMacro()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->name() + ", condition is defined in macro");
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;
// Variable changed in 3rd for-expression
if (Token::simpleMatch(tok2->previous(), "for (")) {
if (tok2->astOperand2() && tok2->astOperand2()->astOperand2() && isVariableChanged(tok2->astOperand2()->astOperand2(), tok2->link(), varid, var->isGlobal(), settings, tokenlist->isCPP())) {
varid = 0U;
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->name() + " used in loop");
}
}
// Variable changed in loop code
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,var->isGlobal(),settings, tokenlist->isCPP())) {
varid = 0U;
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->name() + " 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->name() + ", condition is defined in macro");
}
}
if (varid == 0U)
continue;
// extra logic for unsigned variables 'i>=1' => possible value can also be 0
if (Token::Match(tok, "<|>")) {
if (num != 0)
continue;
if (var->valueType() && var->valueType()->sign != ValueType::Sign::UNSIGNED)
continue;
}
ValueFlow::Value val(tok, num);
val.varId = varid;
ValueFlow::Value val2;
if (num==1U && Token::Match(tok,"<=|>=")) {
if (var->isUnsigned()) {
val2 = ValueFlow::Value(tok,0);
val2.varId = varid;
}
}
Token* startTok = tok->astParent() ? tok->astParent() : tok->previous();
valueFlowReverse(tokenlist, startTok, vartok, val, val2, errorLogger, settings);
}
}
}
static void valueFlowAST(Token *tok, nonneg int varid, const ValueFlow::Value &value, const Settings *settings)
{
if (!tok)
return;
if (tok->varId() == varid)
setTokenValue(tok, value, settings);
valueFlowAST(tok->astOperand1(), varid, value, settings);
if (tok->str() == "&&" && tok->astOperand1() && tok->astOperand1()->getValue(0)) {
ProgramMemory pm;
pm.setValue(varid,value);
if (conditionIsFalse(tok->astOperand1(), pm))
return;
} else if (tok->str() == "||" && tok->astOperand1()) {
const std::list<ValueFlow::Value> &values = tok->astOperand1()->values();
const bool nonzero = std::any_of(values.cbegin(), values.cend(),
[=](const ValueFlow::Value &v) {
return v.intvalue != 0;
});
if (!nonzero)
return;
ProgramMemory pm;
pm.setValue(varid,value);
if (conditionIsTrue(tok->astOperand1(), pm))
return;
}
valueFlowAST(tok->astOperand2(), varid, value, settings);
}
static bool evalAssignment(ValueFlow::Value &lhsValue, const std::string &assign, const ValueFlow::Value &rhsValue)
{
if (lhsValue.isIntValue()) {
if (assign == "=")
lhsValue.intvalue = rhsValue.intvalue;
else if (assign == "+=")
lhsValue.intvalue += rhsValue.intvalue;
else if (assign == "-=")
lhsValue.intvalue -= rhsValue.intvalue;
else if (assign == "*=")
lhsValue.intvalue *= rhsValue.intvalue;
else if (assign == "/=") {
if (rhsValue.intvalue == 0)
return false;
lhsValue.intvalue /= rhsValue.intvalue;
} else if (assign == "%=") {
if (rhsValue.intvalue == 0)
return false;
lhsValue.intvalue %= rhsValue.intvalue;
} else if (assign == "&=")
lhsValue.intvalue &= rhsValue.intvalue;
else if (assign == "|=")
lhsValue.intvalue |= rhsValue.intvalue;
else if (assign == "^=")
lhsValue.intvalue ^= rhsValue.intvalue;
else if (assign == "<<=") {
if (rhsValue.intvalue < 0)
return false;
lhsValue.intvalue <<= rhsValue.intvalue;
} else if (assign == ">>=") {
if (rhsValue.intvalue < 0)
return false;
lhsValue.intvalue >>= rhsValue.intvalue;
} else
return false;
} else if (lhsValue.isFloatValue()) {
if (assign == "=")
lhsValue.intvalue = rhsValue.intvalue;
else if (assign == "+=")
lhsValue.floatValue += rhsValue.intvalue;
else if (assign == "-=")
lhsValue.floatValue -= rhsValue.intvalue;
else if (assign == "*=")
lhsValue.floatValue *= rhsValue.intvalue;
else if (assign == "/=")
lhsValue.floatValue /= rhsValue.intvalue;
else
return false;
} else {
return false;
}
return true;
}
// Check if its an alias of the variable or is being aliased to this variable
static bool isAliasOf(const Variable* var, const Token* tok, nonneg int varid, const ValueFlow::Value& val)
{
if (tok->varId() == varid)
return false;
if (tok->varId() == 0)
return false;
if (isAliasOf(tok, varid))
return true;
if (var && !var->isPointer())
return false;
// Search through non value aliases
if (!val.isNonValue())
return false;
if (val.isInconclusive())
return false;
if (val.isLifetimeValue() && !val.isLocalLifetimeValue())
return false;
if (val.isLifetimeValue() && val.lifetimeKind != ValueFlow::Value::LifetimeKind::Address)
return false;
if (!Token::Match(val.tokvalue, ".|&|*|%var%"))
return false;
if (astHasVar(val.tokvalue, tok->varId()))
return true;
return false;
}
// Check if its an alias of the variable or is being aliased to this variable
static bool isAliasOf(const Variable * var, const Token *tok, nonneg int varid, const std::list<ValueFlow::Value>& values)
{
if (tok->varId() == varid)
return false;
if (tok->varId() == 0)
return false;
if (isAliasOf(tok, varid))
return true;
if (var && !var->isPointer())
return false;
// Search through non value aliases
for (const ValueFlow::Value &val : values) {
if (!val.isNonValue())
continue;
if (val.isInconclusive())
continue;
if (val.isLifetimeValue() && !val.isLocalLifetimeValue())
continue;
if (val.isLifetimeValue() && val.lifetimeKind != ValueFlow::Value::LifetimeKind::Address)
continue;
if (!Token::Match(val.tokvalue, ".|&|*|%var%"))
continue;
if (astHasVar(val.tokvalue, tok->varId()))
return true;
}
return false;
}
static const ValueFlow::Value* getKnownValue(const Token* tok, ValueFlow::Value::ValueType type)
{
if (!tok)
return nullptr;
auto it = std::find_if(tok->values().begin(), tok->values().end(), [&](const ValueFlow::Value& v) {
return v.isKnown() && v.valueType == type;
});
if (it != tok->values().end())
return &*it;
return nullptr;
}
static bool bifurcate(const Token* tok, const std::set<nonneg int>& varids, const Settings* settings, int depth = 20)
{
if (depth < 0)
return false;
if (!tok)
return true;
if (tok->hasKnownIntValue())
return true;
if (Token::Match(tok, "%cop%"))
return bifurcate(tok->astOperand1(), varids, settings, depth) && bifurcate(tok->astOperand2(), varids, settings, depth);
if (Token::Match(tok, "%var%")) {
if (varids.count(tok->varId()) > 0)
return true;
const Variable* var = tok->variable();
if (!var)
return false;
const Token* start = var->declEndToken();
if (!start)
return false;
if (start->strAt(-1) == ")" || start->strAt(-1) == "}")
return false;
if (Token::Match(start, "; %varid% =", var->declarationId()))
start = start->tokAt(2);
if (var->isConst() ||
!isVariableChanged(start->next(), tok, var->declarationId(), var->isGlobal(), settings, true))
return var->isArgument() || bifurcate(start->astOperand2(), varids, settings, depth - 1);
return false;
}
return false;
}
struct SelectMapKeys {
template<class Pair>
typename Pair::first_type operator()(const Pair& p) const {
return p.first;
}
};
struct SelectMapValues {
template<class Pair>
typename Pair::second_type operator()(const Pair& p) const {
return p.second;
}
};
struct ValueFlowForwardAnalyzer : ForwardAnalyzer {
const TokenList* tokenlist;
ProgramMemoryState pms;
ValueFlowForwardAnalyzer()
: tokenlist(nullptr), pms()
{}
ValueFlowForwardAnalyzer(const TokenList* t)
: tokenlist(t), pms()
{}
virtual const ValueFlow::Value* getValue(const Token* tok) const = 0;
virtual ValueFlow::Value* getValue(const Token* tok) = 0;
virtual void makeConditional() = 0;
virtual void addErrorPath(const Token* tok, const std::string& s) = 0;
virtual bool match(const Token* tok) const = 0;
virtual bool isAlias(const Token* tok) const = 0;
using ProgramState = std::unordered_map<nonneg int, ValueFlow::Value>;
virtual ProgramState getProgramState() const = 0;
virtual const ValueType* getValueType(const Token*) const {
return nullptr;
}
virtual int getIndirect(const Token* tok) const {
const ValueFlow::Value* value = getValue(tok);
if (value)
return value->indirect;
return 0;
}
virtual bool isGlobal() const {
return false;
}
virtual bool invalid() const {
return false;
}
bool isCPP() const {
return tokenlist->isCPP();
}
const Settings* getSettings() const {
return tokenlist->getSettings();
}
virtual Action isModified(const Token* tok) const {
Action read = Action::Read;
bool inconclusive = false;
if (isVariableChangedByFunctionCall(tok, getIndirect(tok), getSettings(), &inconclusive))
return read | Action::Invalid;
if (inconclusive)
return read | Action::Inconclusive;
if (isVariableChanged(tok, getIndirect(tok), getSettings(), isCPP())) {
if (Token::Match(tok->astParent(), "*|[|.|++|--"))
return read | Action::Invalid;
return Action::Invalid;
}
return read;
}
virtual Action isAliasModified(const Token* tok) const {
int indirect = 0;
int baseIndirect = 0;
const ValueType* vt = getValueType(tok);
if (vt)
baseIndirect = vt->pointer;
if (tok->valueType())
indirect = std::max<int>(0, tok->valueType()->pointer - baseIndirect);
if (isVariableChanged(tok, indirect, getSettings(), isCPP()))
return Action::Invalid;
return Action::None;
}
virtual Action isWritable(const Token* tok) const {
const ValueFlow::Value* value = getValue(tok);
if (!value)
return Action::None;
if (!(value->isIntValue() || value->isFloatValue()))
return Action::None;
const Token* parent = tok->astParent();
if (parent && parent->isAssignmentOp() && astIsLHS(tok) &&
parent->astOperand2()->hasKnownValue()) {
const Token* rhs = parent->astOperand2();
const ValueFlow::Value* rhsValue = getKnownValue(rhs, ValueFlow::Value::ValueType::INT);
Action a;
if (!rhsValue)
a = Action::Invalid;
else
a = Action::Write;
if (parent->str() != "=")
a |= Action::Read;
return a;
}
// increment/decrement
if (Token::Match(tok->previous(), "++|-- %name%") || Token::Match(tok, "%name% ++|--")) {
return Action::Read | Action::Write;
}
return Action::None;
}
virtual void writeValue(ValueFlow::Value* value, const Token* tok) const {
if (!value)
return;
if (!tok->astParent())
return;
if (tok->astParent()->isAssignmentOp()) {
// TODO: Check result
if (evalAssignment(*value,
tok->astParent()->str(),
*getKnownValue(tok->astParent()->astOperand2(), ValueFlow::Value::ValueType::INT))) {
const std::string info("Compound assignment '" + tok->astParent()->str() + "', assigned value is " +
value->infoString());
if (tok->astParent()->str() == "=")
value->errorPath.clear();
value->errorPath.emplace_back(tok, info);
} else {
// TODO: Don't set to zero
value->intvalue = 0;
}
} else if (tok->astParent()->tokType() == Token::eIncDecOp) {
const bool inc = tok->astParent()->str() == "++";
value->intvalue += (inc ? 1 : -1);
const std::string info(tok->str() + " is " + std::string(inc ? "incremented" : "decremented") +
"', new value is " + value->infoString());
value->errorPath.emplace_back(tok, info);
}
}
virtual Action analyze(const Token* tok) const OVERRIDE {
if (invalid())
return Action::Invalid;
if (match(tok)) {
const Token* parent = tok->astParent();
if (astIsPointer(tok) && (Token::Match(parent, "*|[") || (parent && parent->originalName() == "->")) && getIndirect(tok) <= 0)
return Action::Read;
// Action read = Action::Read;
Action w = isWritable(tok);
if (w != Action::None)
return w;
// Check for modifications by function calls
return isModified(tok);
} else if (tok->isUnaryOp("*")) {
const Token* lifeTok = nullptr;
for (const ValueFlow::Value& v:tok->astOperand1()->values()) {
if (!v.isLocalLifetimeValue())
continue;
if (lifeTok)
return Action::None;
lifeTok = v.tokvalue;
}
if (lifeTok && match(lifeTok)) {
Action a = Action::Read;
if (isModified(tok).isModified())
a = Action::Invalid;
if (Token::Match(tok->astParent(), "%assign%") && astIsLHS(tok))
a |= Action::Read;
return a;
}
return Action::None;
} else if (isAlias(tok)) {
return isAliasModified(tok);
} else if (Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->linkAt(1), ") {")) {
// bailout: global non-const variables
if (isGlobal()) {
return Action::Invalid;
}
}
return Action::None;
}
virtual std::vector<int> evaluate(const Token* tok) const OVERRIDE {
if (tok->hasKnownIntValue())
return {static_cast<int>(tok->values().front().intvalue)};
std::vector<int> result;
ProgramMemory pm = pms.get(tok, getProgramState());
if (conditionIsTrue(tok, pm))
result.push_back(1);
if (conditionIsFalse(tok, pm))
result.push_back(0);
return result;
}
virtual void assume(const Token* tok, bool state, const Token* at) OVERRIDE {
// Update program state
pms.removeModifiedVars(tok);
pms.addState(tok, getProgramState());
pms.assume(tok, state);
const bool isAssert = Token::Match(at, "assert|ASSERT");
if (!isAssert && !Token::simpleMatch(at, "}")) {
std::string s = state ? "true" : "false";
addErrorPath(tok, "Assuming condition is " + s);
}
if (!isAssert)
makeConditional();
}
virtual void update(Token* tok, Action a) OVERRIDE {
ValueFlow::Value* value = getValue(tok);
if (!value)
return;
if (a.isRead())
setTokenValue(tok, *value, getSettings());
if (a.isInconclusive())
lowerToInconclusive();
if (a.isWrite() && tok->astParent()) {
writeValue(value, tok);
}
}
};
struct SingleValueFlowForwardAnalyzer : ValueFlowForwardAnalyzer {
std::unordered_map<nonneg int, const Variable*> varids;
std::unordered_map<nonneg int, const Variable*> aliases;
ValueFlow::Value value;
SingleValueFlowForwardAnalyzer()
: ValueFlowForwardAnalyzer()
{}
SingleValueFlowForwardAnalyzer(const ValueFlow::Value& v, const TokenList* t)
: ValueFlowForwardAnalyzer(t), value(v)
{}
const std::unordered_map<nonneg int, const Variable*>& getVars() const {
return varids;
}
const std::unordered_map<nonneg int, const Variable*>& getAliasedVars() const {
return aliases;
}
virtual const ValueFlow::Value* getValue(const Token*) const OVERRIDE {
return &value;
}
virtual ValueFlow::Value* getValue(const Token*) OVERRIDE {
return &value;
}
virtual void makeConditional() OVERRIDE {
value.conditional = true;
}
virtual void addErrorPath(const Token* tok, const std::string& s) OVERRIDE {
value.errorPath.emplace_back(tok, s);
}
virtual bool isAlias(const Token* tok) const OVERRIDE {
if (value.isLifetimeValue())
return false;
for (const auto& m: {
std::ref(getVars()), std::ref(getAliasedVars())
}) {
for (const auto& p:m.get()) {
nonneg int varid = p.first;
const Variable* var = p.second;
if (tok->varId() == varid)
return true;
if (isAliasOf(var, tok, varid, value))
return true;
}
}
return false;
}
virtual bool isGlobal() const OVERRIDE {
for (const auto&p:getVars()) {
const Variable* var = p.second;
if (!var->isLocal() && !var->isArgument() && !var->isConst())
return true;
}
return false;
}
virtual bool lowerToPossible() OVERRIDE {
if (value.isImpossible())
return false;
value.changeKnownToPossible();
return true;
}
virtual bool lowerToInconclusive() OVERRIDE {
if (value.isImpossible())
return false;
value.setInconclusive();
return true;
}
virtual bool isConditional() const OVERRIDE {
if (value.conditional)
return true;
if (value.condition)
return !value.isImpossible();
return false;
}
virtual bool updateScope(const Token* endBlock, bool) const OVERRIDE {
const Scope* scope = endBlock->scope();
if (!scope)
return false;
if (scope->type == Scope::eLambda) {
return value.isLifetimeValue();
} else if (scope->type == Scope::eIf || scope->type == Scope::eElse || scope->type == Scope::eWhile ||
scope->type == Scope::eFor) {
if (value.isKnown() || value.isImpossible())
return true;
if (value.isLifetimeValue())
return true;
if (isConditional())
return false;
const Token* condTok = getCondTokFromEnd(endBlock);
std::set<nonneg int> varids2;
std::transform(getVars().begin(), getVars().end(), std::inserter(varids2, varids2.begin()), SelectMapKeys{});
return bifurcate(condTok, varids2, getSettings());
}
return false;
}
};
struct VariableForwardAnalyzer : SingleValueFlowForwardAnalyzer {
const Variable* var;
VariableForwardAnalyzer()
: SingleValueFlowForwardAnalyzer(), var(nullptr)
{}
VariableForwardAnalyzer(const Variable* v, const ValueFlow::Value& val, std::vector<const Variable*> paliases, const TokenList* t)
: SingleValueFlowForwardAnalyzer(val, t), var(v) {
varids[var->declarationId()] = var;
for (const Variable* av:paliases) {
if (!av)
continue;
aliases[av->declarationId()] = av;
}
}
virtual const ValueType* getValueType(const Token*) const OVERRIDE {
return var->valueType();
}
virtual bool match(const Token* tok) const OVERRIDE {
return tok->varId() == var->declarationId();
}
virtual ProgramState getProgramState() const OVERRIDE {
ProgramState ps;
ps[var->declarationId()] = value;
return ps;
}
};
static std::vector<const Variable*> getAliasesFromValues(std::list<ValueFlow::Value> values, bool address=false)
{
std::vector<const Variable*> aliases;
for (const ValueFlow::Value& v : values) {
if (!v.tokvalue)
continue;
const Token* lifeTok = nullptr;
for (const ValueFlow::Value& lv:v.tokvalue->values()) {
if (!lv.isLocalLifetimeValue())
continue;
if (address && lv.lifetimeKind != ValueFlow::Value::LifetimeKind::Address)
continue;
if (lifeTok) {
lifeTok = nullptr;
break;
}
lifeTok = lv.tokvalue;
}
if (lifeTok && lifeTok->variable()) {
aliases.push_back(lifeTok->variable());
}
}
return aliases;
}
static void valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
std::list<ValueFlow::Value> values,
std::vector<const Variable*> aliases,
TokenList* const tokenlist,
const Settings* const settings)
{
for (ValueFlow::Value& v : values) {
VariableForwardAnalyzer a(var, v, aliases, tokenlist);
valueFlowGenericForward(startToken, endToken, a, settings);
}
}
static void valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
std::list<ValueFlow::Value> values,
TokenList* const tokenlist,
const Settings* const settings)
{
valueFlowForwardVariable(startToken, endToken, var, std::move(values), getAliasesFromValues(values), tokenlist, settings);
}
// Old deprecated version
static bool valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
const nonneg int,
std::list<ValueFlow::Value> values,
const bool,
const bool,
TokenList* const tokenlist,
ErrorLogger* const,
const Settings* const settings)
{
valueFlowForwardVariable(startToken, endToken, var, std::move(values), tokenlist, settings);
return true;
}
struct ExpressionForwardAnalyzer : SingleValueFlowForwardAnalyzer {
const Token* expr;
bool local;
bool unknown;
ExpressionForwardAnalyzer()
: SingleValueFlowForwardAnalyzer(), expr(nullptr), local(true), unknown(false)
{}
ExpressionForwardAnalyzer(const Token* e, const ValueFlow::Value& val, const TokenList* t)
: SingleValueFlowForwardAnalyzer(val, t), expr(e), local(true), unknown(false) {
setupExprVarIds();
}
virtual const ValueType* getValueType(const Token*) const OVERRIDE {
return expr->valueType();
}
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();
}
void setupExprVarIds() {
visitAstNodes(expr,
[&](const Token *tok) {
if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".") {
// unknown variable
unknown = true;
return ChildrenToVisit::none;
}
if (tok->varId() > 0) {
varids[tok->varId()] = tok->variable();
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(), isCPP()))
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;
});
}
virtual bool invalid() const OVERRIDE {
return unknown;
}
virtual std::vector<int> evaluate(const Token* tok) const OVERRIDE {
if (tok->hasKnownIntValue())
return {static_cast<int>(tok->values().front().intvalue)};
return std::vector<int> {};
}
virtual bool match(const Token* tok) const OVERRIDE {
return isSameExpression(isCPP(), true, expr, tok, getSettings()->library, true, true);
}
virtual ProgramState getProgramState() const OVERRIDE {
return ProgramState{};
}
virtual bool isGlobal() const OVERRIDE {
return !local;
}
};
static void valueFlowForwardExpression(Token* startToken,
const Token* endToken,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
const TokenList* const tokenlist,
const Settings* settings)
{
for (const ValueFlow::Value& v : values) {
ExpressionForwardAnalyzer a(exprTok, v, tokenlist);
valueFlowGenericForward(startToken, endToken, a, settings);
}
}
static const Token* parseBinaryIntOp(const Token* expr, MathLib::bigint& known)
{
if (!expr)
return nullptr;
if (!expr->astOperand1() || !expr->astOperand2())
return nullptr;
const Token* knownTok = nullptr;
const Token* varTok = nullptr;
if (expr->astOperand1()->hasKnownIntValue() && !expr->astOperand2()->hasKnownIntValue()) {
varTok = expr->astOperand2();
knownTok = expr->astOperand1();
} else if (expr->astOperand2()->hasKnownIntValue() && !expr->astOperand1()->hasKnownIntValue()) {
varTok = expr->astOperand1();
knownTok = expr->astOperand2();
}
if (knownTok)
known = knownTok->values().front().intvalue;
return varTok;
}
template <class F>
void transformIntValues(std::list<ValueFlow::Value>& values, F f)
{
std::transform(values.begin(), values.end(), values.begin(), [&](ValueFlow::Value x) {
if (x.isIntValue() || x.isIteratorValue())
x.intvalue = f(x.intvalue);
return x;
});
}
static const Token* solveExprValues(const Token* expr, std::list<ValueFlow::Value>& values)
{
MathLib::bigint intval;
const Token* binaryTok = parseBinaryIntOp(expr, intval);
if (binaryTok && expr->str().size() == 1) {
switch (expr->str()[0]) {
case '+': {
transformIntValues(values, [&](MathLib::bigint x) {
return x - intval;
});
return solveExprValues(binaryTok, values);
}
case '*': {
if (intval == 0)
break;
transformIntValues(values, [&](MathLib::bigint x) {
return x / intval;
});
return solveExprValues(binaryTok, values);
}
case '^': {
transformIntValues(values, [&](MathLib::bigint x) {
return x ^ intval;
});
return solveExprValues(binaryTok, values);
}
}
}
return expr;
}
static void valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
TokenList* const tokenlist,
const Settings* settings)
{
const Token* expr = solveExprValues(exprTok, values);
if (expr->variable()) {
valueFlowForwardVariable(startToken,
endToken,
expr->variable(),
values,
tokenlist,
settings);
} else {
valueFlowForwardExpression(startToken, endToken, expr, values, tokenlist, settings);
}
}
// Old deprecated version
static void valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
const bool,
const bool,
TokenList* const tokenlist,
ErrorLogger* const,
const Settings* settings)
{
valueFlowForward(startToken, endToken, exprTok, std::move(values), tokenlist, settings);
}
static int getArgumentPos(const Variable *var, const Function *f)
{
auto arg_it = std::find_if(f->argumentList.begin(), f->argumentList.end(), [&](const Variable &v) {
return v.nameToken() == var->nameToken();
});
if (arg_it == f->argumentList.end())
return -1;
return std::distance(f->argumentList.begin(), arg_it);
}
std::string lifetimeType(const Token *tok, const ValueFlow::Value *val)
{
std::string result;
if (!val)
return "object";
switch (val->lifetimeKind) {
case ValueFlow::Value::LifetimeKind::Lambda:
result = "lambda";
break;
case ValueFlow::Value::LifetimeKind::Iterator:
result = "iterator";
break;
case ValueFlow::Value::LifetimeKind::Object:
case ValueFlow::Value::LifetimeKind::SubObject:
case ValueFlow::Value::LifetimeKind::Address:
if (astIsPointer(tok))
result = "pointer";
else
result = "object";
break;
}
return result;
}
std::string lifetimeMessage(const Token *tok, const ValueFlow::Value *val, ErrorPath &errorPath)
{
const Token *tokvalue = val ? val->tokvalue : nullptr;
const Variable *tokvar = tokvalue ? tokvalue->variable() : nullptr;
const Token *vartok = tokvar ? tokvar->nameToken() : nullptr;
std::string type = lifetimeType(tok, val);
std::string msg = type;
if (vartok) {
errorPath.emplace_back(vartok, "Variable created here.");
const Variable * var = vartok->variable();
if (var) {
switch (val->lifetimeKind) {
case ValueFlow::Value::LifetimeKind::SubObject:
case ValueFlow::Value::LifetimeKind::Object:
case ValueFlow::Value::LifetimeKind::Address:
if (type == "pointer")
msg += " to local variable";
else
msg += " that points to local variable";
break;
case ValueFlow::Value::LifetimeKind::Lambda:
msg += " that captures local variable";
break;
case ValueFlow::Value::LifetimeKind::Iterator:
msg += " to local container";
break;
}
msg += " '" + var->name() + "'";
}
}
return msg;
}
ValueFlow::Value getLifetimeObjValue(const Token *tok, bool inconclusive)
{
ValueFlow::Value result;
auto pred = [&](const ValueFlow::Value &v) {
if (!v.isLocalLifetimeValue())
return false;
if (!inconclusive && v.isInconclusive())
return false;
if (!v.tokvalue->variable())
return false;
return true;
};
auto it = std::find_if(tok->values().begin(), tok->values().end(), pred);
if (it == tok->values().end())
return result;
result = *it;
// There should only be one lifetime
if (std::find_if(std::next(it), tok->values().end(), pred) != tok->values().end())
return ValueFlow::Value{};
return result;
}
std::vector<LifetimeToken> getLifetimeTokens(const Token* tok, ValueFlow::Value::ErrorPath errorPath, int depth)
{
if (!tok)
return std::vector<LifetimeToken> {};
const Variable *var = tok->variable();
if (depth < 0)
return {{tok, std::move(errorPath)}};
if (var && var->declarationId() == tok->varId()) {
if (var->isReference() || var->isRValueReference()) {
if (!var->declEndToken())
return {{tok, true, std::move(errorPath)}};
if (var->isArgument()) {
errorPath.emplace_back(var->declEndToken(), "Passed to reference.");
return {{tok, true, std::move(errorPath)}};
} else if (Token::simpleMatch(var->declEndToken(), "=")) {
errorPath.emplace_back(var->declEndToken(), "Assigned to reference.");
const Token *vartok = var->declEndToken()->astOperand2();
if (vartok == tok || (var->isConst() && isTemporary(true, vartok, nullptr, true)))
return {{tok, true, std::move(errorPath)}};
if (vartok)
return getLifetimeTokens(vartok, std::move(errorPath), depth - 1);
} else if (Token::simpleMatch(var->nameToken()->astParent(), ":") &&
var->nameToken()->astParent()->astParent() &&
Token::simpleMatch(var->nameToken()->astParent()->astParent()->previous(), "for (")) {
errorPath.emplace_back(var->nameToken(), "Assigned to reference.");
const Token* vartok = var->nameToken();
if (vartok == tok)
return {{tok, true, std::move(errorPath)}};
const Token* contok = var->nameToken()->astParent()->astOperand2();
if (contok)
return getLifetimeTokens(contok, std::move(errorPath), depth - 1);
} else {
return std::vector<LifetimeToken> {};
}
}
} else if (Token::Match(tok->previous(), "%name% (")) {
const Function *f = tok->previous()->function();
if (f) {
if (!Function::returnsReference(f))
return {{tok, std::move(errorPath)}};
std::vector<LifetimeToken> result;
std::vector<const Token*> returns = Function::findReturns(f);
for (const Token* returnTok : returns) {
if (returnTok == tok)
continue;
for (LifetimeToken& lt : getLifetimeTokens(returnTok, std::move(errorPath), depth - 1)) {
const Token* argvarTok = lt.token;
const Variable* argvar = argvarTok->variable();
if (!argvar)
continue;
if (argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) {
int n = getArgumentPos(argvar, f);
if (n < 0)
return std::vector<LifetimeToken> {};
std::vector<const Token*> args = getArguments(tok->previous());
// TODO: Track lifetimes of default parameters
if (n >= args.size())
return std::vector<LifetimeToken> {};
const Token* argTok = args[n];
lt.errorPath.emplace_back(returnTok, "Return reference.");
lt.errorPath.emplace_back(tok->previous(), "Called function passing '" + argTok->str() + "'.");
std::vector<LifetimeToken> arglts = LifetimeToken::setInconclusive(
getLifetimeTokens(argTok, std::move(lt.errorPath), depth - 1), returns.size() > 1);
result.insert(result.end(), arglts.begin(), arglts.end());
}
}
}
return result;
} else if (Token::Match(tok->tokAt(-2), ". %name% (") && tok->tokAt(-2)->originalName() != "->" && astIsContainer(tok->tokAt(-2)->astOperand1())) {
const Library::Container* library = getLibraryContainer(tok->tokAt(-2)->astOperand1());
Library::Container::Yield y = library->getYield(tok->previous()->str());
if (y == Library::Container::Yield::AT_INDEX || y == Library::Container::Yield::ITEM) {
errorPath.emplace_back(tok->previous(), "Accessing container.");
return LifetimeToken::setAddressOf(
getLifetimeTokens(tok->tokAt(-2)->astOperand1(), std::move(errorPath), depth - 1), false);
}
}
} else if (Token::Match(tok, ".|::|[")) {
const Token *vartok = tok;
while (vartok) {
if (vartok->str() == "[" || vartok->originalName() == "->")
vartok = vartok->astOperand1();
else if (vartok->str() == "." || vartok->str() == "::")
vartok = vartok->astOperand2();
else
break;
}
if (!vartok)
return {{tok, std::move(errorPath)}};
const Variable *tokvar = vartok->variable();
if (!astIsContainer(vartok) && !(tokvar && tokvar->isArray() && !tokvar->isArgument()) &&
(Token::Match(vartok->astParent(), "[|*") || vartok->astParent()->originalName() == "->")) {
for (const ValueFlow::Value &v : vartok->values()) {
if (!v.isLocalLifetimeValue())
continue;
errorPath.insert(errorPath.end(), v.errorPath.begin(), v.errorPath.end());
return getLifetimeTokens(v.tokvalue, std::move(errorPath));
}
} else {
return LifetimeToken::setAddressOf(getLifetimeTokens(vartok, std::move(errorPath)),
!(astIsContainer(vartok) && Token::simpleMatch(vartok->astParent(), "[")));
}
}
return {{tok, std::move(errorPath)}};
}
static const Token* getLifetimeToken(const Token* tok, ValueFlow::Value::ErrorPath& errorPath, bool* addressOf = nullptr)
{
std::vector<LifetimeToken> lts = getLifetimeTokens(tok);
if (lts.size() != 1)
return nullptr;
if (lts.front().inconclusive)
return nullptr;
if (addressOf)
*addressOf = lts.front().addressOf;
errorPath.insert(errorPath.end(), lts.front().errorPath.begin(), lts.front().errorPath.end());
return lts.front().token;
}
const Variable* getLifetimeVariable(const Token* tok, ValueFlow::Value::ErrorPath& errorPath, bool* addressOf)
{
const Token* tok2 = getLifetimeToken(tok, errorPath, addressOf);
if (tok2 && tok2->variable())
return tok2->variable();
return nullptr;
}
const Variable* getLifetimeVariable(const Token* tok)
{
ValueFlow::Value::ErrorPath errorPath;
return getLifetimeVariable(tok, errorPath, nullptr);
}
static bool isNotLifetimeValue(const ValueFlow::Value& val)
{
return !val.isLifetimeValue();
}
static bool isLifetimeOwned(const ValueType *vt, const ValueType *vtParent)
{
if (!vtParent)
return false;
if (!vt) {
if (vtParent->type == ValueType::CONTAINER)
return true;
return false;
}
if (vt->type != ValueType::UNKNOWN_TYPE && vtParent->type != ValueType::UNKNOWN_TYPE) {
if (vt->pointer != vtParent->pointer)
return true;
if (vt->type != vtParent->type) {
if (vtParent->type == ValueType::RECORD)
return true;
if (vtParent->type == ValueType::CONTAINER)
return true;
}
}
return false;
}
static bool isLifetimeBorrowed(const ValueType *vt, const ValueType *vtParent)
{
if (!vtParent)
return false;
if (!vt)
return false;
if (vt->type != ValueType::UNKNOWN_TYPE && vtParent->type != ValueType::UNKNOWN_TYPE && vtParent->container == vt->container) {
if (vtParent->pointer > vt->pointer)
return true;
if (vtParent->pointer < vt->pointer && vtParent->isIntegral())
return true;
if (vtParent->str() == vt->str())
return true;
if (vtParent->pointer == vt->pointer && vtParent->type == vt->type && vtParent->isIntegral())
// sign conversion
return true;
}
return false;
}
static const Token* skipCVRefs(const Token* tok, const Token* endTok)
{
while (tok != endTok && Token::Match(tok, "const|volatile|auto|&|&&"))
tok = tok->next();
return tok;
}
static bool isNotEqual(std::pair<const Token*, const Token*> x, std::pair<const Token*, const Token*> y)
{
const Token* start1 = x.first;
const Token* start2 = y.first;
if (start1 == nullptr || start2 == nullptr)
return false;
while (start1 != x.second && start2 != y.second) {
const Token* tok1 = skipCVRefs(start1, x.second);
if (tok1 != start1) {
start1 = tok1;
continue;
}
const Token* tok2 = skipCVRefs(start2, y.second);
if (tok2 != start2) {
start2 = tok2;
continue;
}
if (start1->str() != start2->str())
return true;
start1 = start1->next();
start2 = start2->next();
}
start1 = skipCVRefs(start1, x.second);
start2 = skipCVRefs(start2, y.second);
return !(start1 == x.second && start2 == y.second);
}
static bool isNotEqual(std::pair<const Token*, const Token*> x, const std::string& y)
{
TokenList tokenList(nullptr);
std::istringstream istr(y);
tokenList.createTokens(istr);
return isNotEqual(x, std::make_pair(tokenList.front(), tokenList.back()));
}
static bool isNotEqual(std::pair<const Token*, const Token*> x, const ValueType* y)
{
if (y == nullptr)
return false;
if (y->originalTypeName.empty())
return false;
return isNotEqual(x, y->originalTypeName);
}
bool isLifetimeBorrowed(const Token *tok, const Settings *settings)
{
if (!tok)
return true;
if (tok->str() == ",")
return true;
if (!tok->astParent())
return true;
if (!Token::Match(tok->astParent()->previous(), "%name% (") && !Token::simpleMatch(tok->astParent(), ",")) {
if (!Token::simpleMatch(tok, "{")) {
const ValueType *vt = tok->valueType();
const ValueType *vtParent = tok->astParent()->valueType();
if (isLifetimeBorrowed(vt, vtParent))
return true;
if (isLifetimeOwned(vt, vtParent))
return false;
}
if (Token::Match(tok->astParent(), "return|(|{|%assign%")) {
const Type *t = Token::typeOf(tok);
const Type *parentT = Token::typeOf(tok->astParent());
if (t && parentT) {
if (t->classDef && parentT->classDef && t->classDef != parentT->classDef)
return false;
} else {
std::pair<const Token*, const Token*> decl = Token::typeDecl(tok);
std::pair<const Token*, const Token*> parentdecl = Token::typeDecl(tok->astParent());
if (isNotEqual(decl, parentdecl))
return false;
if (isNotEqual(decl, tok->astParent()->valueType()))
return false;
if (isNotEqual(parentdecl, tok->valueType()))
return false;
}
}
} else if (Token::Match(tok->astParent()->tokAt(-3), "%var% . push_back|push_front|insert|push (") &&
astIsContainer(tok->astParent()->tokAt(-3))) {
const ValueType *vt = tok->valueType();
const ValueType *vtCont = tok->astParent()->tokAt(-3)->valueType();
if (!vtCont->containerTypeToken)
return true;
ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings);
if (isLifetimeBorrowed(vt, &vtParent))
return true;
if (isLifetimeOwned(vt, &vtParent))
return false;
}
return true;
}
static void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings);
static void valueFlowLifetimeConstructor(Token *tok,
TokenList *tokenlist,
ErrorLogger *errorLogger,
const Settings *settings);
static void valueFlowForwardLifetime(Token * tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
Token *parent = tok->astParent();
while (parent && (parent->isArithmeticalOp() || parent->str() == ","))
parent = parent->astParent();
if (!parent)
return;
// Assignment
if (parent->str() == "=" && (!parent->astParent() || Token::simpleMatch(parent->astParent(), ";"))) {
// Rhs values..
if (!parent->astOperand2() || parent->astOperand2()->values().empty())
return;
if (!isLifetimeBorrowed(parent->astOperand2(), settings))
return;
std::vector<const Variable*> vars = getLHSVariables(parent);
const Token* endOfVarScope = nullptr;
for (const Variable* var : vars) {
if (var && var->isLocal())
endOfVarScope = var->typeStartToken()->scope()->bodyEnd;
else if (!endOfVarScope)
endOfVarScope = tok->scope()->bodyEnd;
}
// Only forward lifetime values
std::list<ValueFlow::Value> values = parent->astOperand2()->values();
values.remove_if(&isNotLifetimeValue);
// Skip RHS
const Token *nextExpression = nextAfterAstRightmostLeaf(parent);
if (Token::Match(parent->astOperand1(), ".|[|(")) {
valueFlowForwardExpression(
const_cast<Token*>(nextExpression), endOfVarScope, parent->astOperand1(), values, tokenlist, settings);
for (ValueFlow::Value& val : values) {
if (val.lifetimeKind == ValueFlow::Value::LifetimeKind::Address)
val.lifetimeKind = ValueFlow::Value::LifetimeKind::SubObject;
}
}
for (const Variable* var : vars) {
valueFlowForwardVariable(const_cast<Token*>(nextExpression),
endOfVarScope,
var,
var->declarationId(),
values,
false,
false,
tokenlist,
errorLogger,
settings);
if (tok->astTop() && Token::simpleMatch(tok->astTop()->previous(), "for (") &&
Token::simpleMatch(tok->astTop()->link(), ") {")) {
Token* start = tok->astTop()->link()->next();
valueFlowForwardVariable(
start, start->link(), var, var->declarationId(), values, false, false, tokenlist, errorLogger, settings);
}
}
// Constructor
} else if (Token::simpleMatch(parent, "{") && !isScopeBracket(parent)) {
valueFlowLifetimeConstructor(parent, tokenlist, errorLogger, settings);
valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings);
// Function call
} else if (Token::Match(parent->previous(), "%name% (")) {
valueFlowLifetimeFunction(parent->previous(), tokenlist, errorLogger, settings);
valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings);
// Variable
} else if (tok->variable()) {
const Variable *var = tok->variable();
const Token *endOfVarScope = var->scope()->bodyEnd;
std::list<ValueFlow::Value> values = tok->values();
const Token *nextExpression = nextAfterAstRightmostLeaf(parent);
// Only forward lifetime values
values.remove_if(&isNotLifetimeValue);
valueFlowForwardVariable(const_cast<Token*>(nextExpression),
endOfVarScope,
var,
var->declarationId(),
values,
false,
false,
tokenlist,
errorLogger,
settings);
}
}
struct LifetimeStore {
const Token *argtok;
std::string message;
ValueFlow::Value::LifetimeKind type;
ErrorPath errorPath;
bool inconclusive;
LifetimeStore()
: argtok(nullptr), message(), type(), errorPath(), inconclusive(false)
{}
LifetimeStore(const Token *argtok,
const std::string &message,
ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object,
bool inconclusive = false)
: argtok(argtok), message(message), type(type), errorPath(), inconclusive(inconclusive)
{}
static LifetimeStore fromFunctionArg(const Function * f, Token *tok, const Variable *var, TokenList *tokenlist, ErrorLogger *errorLogger) {
if (!var)
return LifetimeStore{};
if (!var->isArgument())
return LifetimeStore{};
int n = getArgumentPos(var, f);
if (n < 0)
return LifetimeStore{};
std::vector<const Token *> args = getArguments(tok);
if (n >= args.size()) {
if (tokenlist->getSettings()->debugwarnings)
bailout(tokenlist,
errorLogger,
tok,
"Argument mismatch: Function '" + tok->str() + "' returning lifetime from argument index " +
std::to_string(n) + " but only " + std::to_string(args.size()) +
" arguments are available.");
return LifetimeStore{};
}
const Token *argtok2 = args[n];
return LifetimeStore{argtok2, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Object};
}
template <class Predicate>
void byRef(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const {
if (!settings->inconclusive && inconclusive)
return;
if (!argtok)
return;
for (const LifetimeToken& lt : getLifetimeTokens(argtok)) {
if (!settings->inconclusive && lt.inconclusive)
continue;
ErrorPath er = errorPath;
er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end());
if (!lt.token)
return;
if (!pred(lt.token))
return;
er.emplace_back(argtok, message);
ValueFlow::Value value;
value.valueType = ValueFlow::Value::LIFETIME;
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local;
value.tokvalue = lt.token;
value.errorPath = std::move(er);
value.lifetimeKind = type;
value.setInconclusive(lt.inconclusive || inconclusive);
// Don't add the value a second time
if (std::find(tok->values().begin(), tok->values().end(), value) != tok->values().end())
return;
setTokenValue(tok, value, tokenlist->getSettings());
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
void byRef(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const {
byRef(tok, tokenlist, errorLogger, settings, [](const Token *) {
return true;
});
}
template <class Predicate>
void byVal(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const {
if (!settings->inconclusive && inconclusive)
return;
if (!argtok)
return;
if (argtok->values().empty()) {
ErrorPath er;
er.emplace_back(argtok, message);
const Variable *var = getLifetimeVariable(argtok, er);
if (var && var->isArgument()) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::LIFETIME;
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Argument;
value.tokvalue = var->nameToken();
value.errorPath = er;
value.lifetimeKind = type;
value.setInconclusive(inconclusive);
// Don't add the value a second time
if (std::find(tok->values().begin(), tok->values().end(), value) != tok->values().end())
return;
setTokenValue(tok, value, tokenlist->getSettings());
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
for (const ValueFlow::Value &v : argtok->values()) {
if (!v.isLifetimeValue())
continue;
const Token *tok3 = v.tokvalue;
for (const LifetimeToken& lt : getLifetimeTokens(tok3)) {
if (!settings->inconclusive && lt.inconclusive)
continue;
ErrorPath er = v.errorPath;
er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end());
if (!lt.token)
return;
if (!pred(lt.token))
return;
er.emplace_back(argtok, message);
er.insert(er.end(), errorPath.begin(), errorPath.end());
ValueFlow::Value value;
value.valueType = ValueFlow::Value::LIFETIME;
value.lifetimeScope = v.lifetimeScope;
value.tokvalue = lt.token;
value.errorPath = std::move(er);
value.lifetimeKind = type;
value.setInconclusive(lt.inconclusive || v.isInconclusive() || inconclusive);
// Don't add the value a second time
if (std::find(tok->values().begin(), tok->values().end(), value) != tok->values().end())
continue;
setTokenValue(tok, value, tokenlist->getSettings());
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
}
void byVal(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const {
byVal(tok, tokenlist, errorLogger, settings, [](const Token *) {
return true;
});
}
template <class Predicate>
void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const {
if (!settings->inconclusive && inconclusive)
return;
if (!argtok)
return;
for (const ValueFlow::Value &v : argtok->values()) {
if (!v.isLifetimeValue())
continue;
const Token *tok2 = v.tokvalue;
ErrorPath er = v.errorPath;
const Variable *var = getLifetimeVariable(tok2, er);
er.insert(er.end(), errorPath.begin(), errorPath.end());
if (!var)
continue;
for (const Token *tok3 = tok; tok3 && tok3 != var->declEndToken(); tok3 = tok3->previous()) {
if (tok3->varId() == var->declarationId()) {
LifetimeStore{tok3, message, type, inconclusive} .byVal(tok, tokenlist, errorLogger, settings, pred);
break;
}
}
}
}
void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const {
byDerefCopy(tok, tokenlist, errorLogger, settings, [](const Token *) {
return true;
});
}
};
static void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
if (!Token::Match(tok, "%name% ("))
return;
int returnContainer = settings->library.returnValueContainer(tok);
if (returnContainer >= 0) {
std::vector<const Token *> args = getArguments(tok);
for (int argnr = 1; argnr <= args.size(); ++argnr) {
const Library::ArgumentChecks::IteratorInfo *i = settings->library.getArgIteratorInfo(tok, argnr);
if (!i)
continue;
if (i->container != returnContainer)
continue;
const Token * const argTok = args[argnr - 1];
// Check if lifetime is available to avoid adding the lifetime twice
ValueFlow::Value val = getLifetimeObjValue(argTok);
if (val.tokvalue) {
LifetimeStore{argTok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Iterator} .byVal(
tok->next(), tokenlist, errorLogger, settings);
break;
}
}
} else if (Token::Match(tok->tokAt(-2), "std :: ref|cref|tie|front_inserter|back_inserter")) {
for (const Token *argtok : getArguments(tok)) {
LifetimeStore{argtok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Object} .byRef(
tok->next(), tokenlist, errorLogger, settings);
}
} else if (Token::Match(tok->tokAt(-2), "std :: make_tuple|tuple_cat|make_pair|make_reverse_iterator|next|prev|move")) {
for (const Token *argtok : getArguments(tok)) {
LifetimeStore{argtok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Object} .byVal(
tok->next(), tokenlist, errorLogger, settings);
}
} else if (Token::Match(tok->tokAt(-2), "%var% . push_back|push_front|insert|push|assign") &&
astIsContainer(tok->tokAt(-2))) {
Token *vartok = tok->tokAt(-2);
std::vector<const Token *> args = getArguments(tok);
std::size_t n = args.size();
if (n > 1 && Token::typeStr(args[n - 2]) == Token::typeStr(args[n - 1]) &&
(((astIsIterator(args[n - 2]) && astIsIterator(args[n - 1])) ||
(astIsPointer(args[n - 2]) && astIsPointer(args[n - 1]))))) {
LifetimeStore{args.back(), "Added to container '" + vartok->str() + "'.", ValueFlow::Value::LifetimeKind::Object} .byDerefCopy(
vartok, tokenlist, errorLogger, settings);
} else if (!args.empty() && isLifetimeBorrowed(args.back(), settings)) {
LifetimeStore{args.back(), "Added to container '" + vartok->str() + "'.", ValueFlow::Value::LifetimeKind::Object} .byVal(
vartok, tokenlist, errorLogger, settings);
}
} else if (tok->function()) {
const Function *f = tok->function();
if (Function::returnsReference(f))
return;
std::vector<const Token*> returns = Function::findReturns(f);
const bool inconclusive = returns.size() > 1;
for (const Token* returnTok : returns) {
if (returnTok == tok)
continue;
const Variable *returnVar = returnTok->variable();
if (returnVar && returnVar->isArgument() && (returnVar->isConst() || !isVariableChanged(returnVar, settings, tokenlist->isCPP()))) {
LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, returnVar, tokenlist, errorLogger);
ls.inconclusive = inconclusive;
ls.byVal(tok->next(), tokenlist, errorLogger, settings);
}
for (const ValueFlow::Value &v : returnTok->values()) {
if (!v.isLifetimeValue())
continue;
if (!v.tokvalue)
continue;
const Variable *var = v.tokvalue->variable();
LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, var, tokenlist, errorLogger);
if (!ls.argtok)
continue;
ls.inconclusive = inconclusive;
ls.errorPath = v.errorPath;
ls.errorPath.emplace_front(returnTok, "Return " + lifetimeType(returnTok, &v) + ".");
if (var->isReference() || var->isRValueReference()) {
ls.byRef(tok->next(), tokenlist, errorLogger, settings);
} else if (v.isArgumentLifetimeValue()) {
ls.byVal(tok->next(), tokenlist, errorLogger, settings);
}
}
}
}
}
static void valueFlowLifetimeConstructor(Token* tok,
const Type* t,
TokenList* tokenlist,
ErrorLogger* errorLogger,
const Settings* settings)
{
if (!t)
return;
if (!Token::Match(tok, "(|{"))
return;
const Scope* scope = t->classScope;
if (!scope)
return;
// Only support aggregate constructors for now
if (scope->numConstructors == 0 && t->derivedFrom.empty() && (t->isClassType() || t->isStructType())) {
std::vector<const Token*> args = getArguments(tok);
std::size_t i = 0;
for (const Variable& var : scope->varlist) {
if (i >= args.size())
break;
const Token* argtok = args[i];
LifetimeStore ls{
argtok, "Passed to constructor of '" + t->name() + "'.", ValueFlow::Value::LifetimeKind::Object};
if (var.isReference() || var.isRValueReference()) {
ls.byRef(tok, tokenlist, errorLogger, settings);
} else {
ls.byVal(tok, tokenlist, errorLogger, settings);
}
i++;
}
}
}
static bool hasInitList(const Token* tok)
{
if (astIsPointer(tok))
return true;
if (astIsContainer(tok)) {
const Library::Container * library = getLibraryContainer(tok);
if (!library)
return false;
return library->hasInitializerListConstructor;
}
return false;
}
static void valueFlowLifetimeConstructor(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings)
{
if (!Token::Match(tok, "(|{"))
return;
Token* parent = tok->astParent();
while (Token::simpleMatch(parent, ","))
parent = parent->astParent();
if (Token::simpleMatch(parent, "{") && hasInitList(parent->astParent())) {
valueFlowLifetimeConstructor(tok, Token::typeOf(parent->previous()), tokenlist, errorLogger, settings);
} else if (Token::simpleMatch(tok, "{") && hasInitList(parent)) {
std::vector<const Token *> args = getArguments(tok);
// Assume range constructor if passed a pair of iterators
if (astIsContainer(parent) && args.size() == 2 && astIsIterator(args[0]) && astIsIterator(args[1])) {
for (const Token *argtok : args) {
LifetimeStore ls{argtok, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::Object};
ls.byDerefCopy(tok, tokenlist, errorLogger, settings);
}
} else {
for (const Token *argtok : args) {
LifetimeStore ls{argtok, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::Object};
ls.byVal(tok, tokenlist, errorLogger, settings);
}
}
} else if (const Type* t = Token::typeOf(tok->previous())) {
valueFlowLifetimeConstructor(tok, t, tokenlist, errorLogger, settings);
}
}
struct Lambda {
explicit Lambda(const Token * tok)
: capture(nullptr), arguments(nullptr), returnTok(nullptr), bodyTok(nullptr) {
if (!Token::simpleMatch(tok, "[") || !tok->link())
return;
capture = tok;
if (Token::simpleMatch(capture->link(), "] (")) {
arguments = capture->link()->next();
}
const Token * afterArguments = arguments ? arguments->link()->next() : capture->link()->next();
if (afterArguments && afterArguments->originalName() == "->") {
returnTok = afterArguments->next();
bodyTok = Token::findsimplematch(returnTok, "{");
} else if (Token::simpleMatch(afterArguments, "{")) {
bodyTok = afterArguments;
}
}
const Token * capture;
const Token * arguments;
const Token * returnTok;
const Token * bodyTok;
bool isLambda() const {
return capture && bodyTok;
}
};
static bool isDecayedPointer(const Token *tok)
{
if (!tok)
return false;
if (!tok->astParent())
return false;
if (astIsPointer(tok->astParent()) && !Token::simpleMatch(tok->astParent(), "return"))
return true;
if (tok->astParent()->isConstOp())
return true;
if (!Token::simpleMatch(tok->astParent(), "return"))
return false;
return astIsPointer(tok->astParent());
}
static void valueFlowLifetime(TokenList *tokenlist, SymbolDatabase*, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->scope())
continue;
if (tok->scope()->type == Scope::eGlobal)
continue;
Lambda lam(tok);
// Lamdas
if (lam.isLambda()) {
const Scope * bodyScope = lam.bodyTok->scope();
std::set<const Scope *> scopes;
auto isCapturingVariable = [&](const Token *varTok) {
const Variable *var = varTok->variable();
if (!var)
return false;
if (!var->isLocal() && !var->isArgument())
return false;
const Scope *scope = var->scope();
if (!scope)
return false;
if (scopes.count(scope) > 0)
return false;
if (scope->isNestedIn(bodyScope))
return false;
scopes.insert(scope);
return true;
};
// TODO: Handle explicit capture
bool captureByRef = Token::Match(lam.capture, "[ & ]");
bool captureByValue = Token::Match(lam.capture, "[ = ]");
for (const Token * tok2 = lam.bodyTok; tok2 != lam.bodyTok->link(); tok2 = tok2->next()) {
ErrorPath errorPath;
if (captureByRef) {
LifetimeStore{tok2, "Lambda captures variable by reference here.", ValueFlow::Value::LifetimeKind::Lambda} .byRef(
tok, tokenlist, errorLogger, settings, isCapturingVariable);
} else if (captureByValue) {
LifetimeStore{tok2, "Lambda captures variable by value here.", ValueFlow::Value::LifetimeKind::Lambda} .byVal(
tok, tokenlist, errorLogger, settings, isCapturingVariable);
}
}
}
// address of
else if (tok->isUnaryOp("&")) {
for (const LifetimeToken& lt : getLifetimeTokens(tok->astOperand1())) {
if (!settings->inconclusive && lt.inconclusive)
continue;
ErrorPath errorPath = lt.errorPath;
errorPath.emplace_back(tok, "Address of variable taken here.");
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local;
value.tokvalue = lt.token;
value.errorPath = std::move(errorPath);
if (lt.addressOf || astIsPointer(lt.token) || !Token::Match(lt.token->astParent(), ".|["))
value.lifetimeKind = ValueFlow::Value::LifetimeKind::Address;
value.setInconclusive(lt.inconclusive);
setTokenValue(tok, value, tokenlist->getSettings());
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
// container lifetimes
else if (astIsContainer(tok)) {
Token * parent = astParentSkipParens(tok);
if (!Token::Match(parent, ". %name% ("))
continue;
bool isContainerOfPointers = true;
const Token* containerTypeToken = tok->valueType()->containerTypeToken;
if (containerTypeToken) {
ValueType vt = ValueType::parseDecl(containerTypeToken, settings);
isContainerOfPointers = vt.pointer > 0;
}
LifetimeStore ls;
if (astIsIterator(parent->tokAt(2)))
ls = LifetimeStore{tok, "Iterator to container is created here.", ValueFlow::Value::LifetimeKind::Iterator};
else if ((astIsPointer(parent->tokAt(2)) && !isContainerOfPointers) || Token::Match(parent->next(), "data|c_str"))
ls = LifetimeStore{tok, "Pointer to container is created here.", ValueFlow::Value::LifetimeKind::Object};
else
continue;
// Dereferencing
if (tok->isUnaryOp("*") || parent->originalName() == "->")
ls.byDerefCopy(parent->tokAt(2), tokenlist, errorLogger, settings);
else
ls.byRef(parent->tokAt(2), tokenlist, errorLogger, settings);
}
// Check constructors
else if (Token::Match(tok, "=|return|%type%|%var% {")) {
valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings);
}
// Check function calls
else if (Token::Match(tok, "%name% (")) {
valueFlowLifetimeFunction(tok, tokenlist, errorLogger, settings);
}
// Check variables
else if (tok->variable()) {
ErrorPath errorPath;
const Variable * var = getLifetimeVariable(tok, errorPath);
if (!var)
continue;
if (var->nameToken() == tok)
continue;
if (var->isArray() && !var->isStlType() && !var->isArgument() && isDecayedPointer(tok)) {
errorPath.emplace_back(tok, "Array decayed to pointer here.");
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local;
value.tokvalue = var->nameToken();
value.errorPath = errorPath;
setTokenValue(tok, value, tokenlist->getSettings());
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
// Forward any lifetimes
else if (std::any_of(tok->values().begin(), tok->values().end(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) {
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
}
static bool isStdMoveOrStdForwarded(Token * tok, ValueFlow::Value::MoveKind * moveKind, Token ** varTok = nullptr)
{
if (tok->str() != "std")
return false;
ValueFlow::Value::MoveKind kind = ValueFlow::Value::MoveKind::NonMovedVariable;
Token * variableToken = nullptr;
if (Token::Match(tok, "std :: move ( %var% )")) {
variableToken = tok->tokAt(4);
kind = ValueFlow::Value::MoveKind::MovedVariable;
} else if (Token::simpleMatch(tok, "std :: forward <")) {
const Token * const leftAngle = tok->tokAt(3);
Token * rightAngle = leftAngle->link();
if (Token::Match(rightAngle, "> ( %var% )")) {
variableToken = rightAngle->tokAt(2);
kind = ValueFlow::Value::MoveKind::ForwardedVariable;
}
}
if (!variableToken)
return false;
if (variableToken->strAt(2) == ".") // Only partially moved
return false;
if (variableToken->valueType() && variableToken->valueType()->type >= ValueType::Type::VOID)
return false;
if (moveKind != nullptr)
*moveKind = kind;
if (varTok != nullptr)
*varTok = variableToken;
return true;
}
static bool isOpenParenthesisMemberFunctionCallOfVarId(const Token * openParenthesisToken, nonneg int varId)
{
const Token * varTok = openParenthesisToken->tokAt(-3);
return Token::Match(varTok, "%varid% . %name% (", varId) &&
varTok->next()->originalName() == emptyString;
}
static const Token * findOpenParentesisOfMove(const Token * moveVarTok)
{
const Token * tok = moveVarTok;
while (tok && tok->str() != "(")
tok = tok->previous();
return tok;
}
static const Token * findEndOfFunctionCallForParameter(const Token * parameterToken)
{
if (!parameterToken)
return nullptr;
const Token * parent = parameterToken->astParent();
while (parent && !parent->isOp() && parent->str() != "(")
parent = parent->astParent();
if (!parent)
return nullptr;
return nextAfterAstRightmostLeaf(parent);
}
static void valueFlowAfterMove(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
if (!tokenlist->isCPP() || settings->standards.cpp < Standards::CPP11)
return;
for (const Scope * scope : symboldatabase->functionScopes) {
if (!scope)
continue;
const Token * start = scope->bodyStart;
if (scope->function) {
const Token * memberInitializationTok = scope->function->constructorMemberInitialization();
if (memberInitializationTok)
start = memberInitializationTok;
}
for (Token* tok = const_cast<Token*>(start); tok != scope->bodyEnd; tok = tok->next()) {
Token * varTok;
if (Token::Match(tok, "%var% . reset|clear (") && tok->next()->originalName() == emptyString) {
varTok = tok;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::MOVED;
value.moveKind = ValueFlow::Value::MoveKind::NonMovedVariable;
value.errorPath.emplace_back(tok, "Calling " + tok->next()->expressionString() + " makes " + tok->str() + " 'non-moved'");
value.setKnown();
std::list<ValueFlow::Value> values;
values.push_back(value);
const Variable *var = varTok->variable();
if (!var || (!var->isLocal() && !var->isArgument()))
continue;
const int varId = varTok->varId();
const Token * const endOfVarScope = var->scope()->bodyEnd;
setTokenValue(varTok, value, settings);
valueFlowForwardVariable(
varTok->next(), endOfVarScope, var, varId, values, false, false, tokenlist, errorLogger, settings);
continue;
}
ValueFlow::Value::MoveKind moveKind;
if (!isStdMoveOrStdForwarded(tok, &moveKind, &varTok))
continue;
const int varId = varTok->varId();
// x is not MOVED after assignment if code is: x = ... std::move(x) .. ;
const Token *parent = tok->astParent();
while (parent && parent->str() != "=" && parent->str() != "return" &&
!(parent->str() == "(" && isOpenParenthesisMemberFunctionCallOfVarId(parent, varId)))
parent = parent->astParent();
if (parent &&
(parent->str() == "return" || // MOVED in return statement
parent->str() == "(")) // MOVED in self assignment, isOpenParenthesisMemberFunctionCallOfVarId == true
continue;
if (parent && parent->astOperand1() && parent->astOperand1()->varId() == varId)
continue;
const Variable *var = varTok->variable();
if (!var)
continue;
const Token * const endOfVarScope = var->scope()->bodyEnd;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::MOVED;
value.moveKind = moveKind;
if (moveKind == ValueFlow::Value::MoveKind::MovedVariable)
value.errorPath.emplace_back(tok, "Calling std::move(" + varTok->str() + ")");
else // if (moveKind == ValueFlow::Value::ForwardedVariable)
value.errorPath.emplace_back(tok, "Calling std::forward(" + varTok->str() + ")");
value.setKnown();
std::list<ValueFlow::Value> values;
values.push_back(value);
const Token * openParentesisOfMove = findOpenParentesisOfMove(varTok);
const Token * endOfFunctionCall = findEndOfFunctionCallForParameter(openParentesisOfMove);
if (endOfFunctionCall)
valueFlowForwardVariable(const_cast<Token*>(endOfFunctionCall),
endOfVarScope,
var,
varId,
values,
false,
false,
tokenlist,
errorLogger,
settings);
}
}
}
static void valueFlowForwardAssign(Token * const tok,
const Variable * const var,
std::list<ValueFlow::Value> values,
const bool constValue,
const bool init,
TokenList * const tokenlist,
ErrorLogger * const errorLogger,
const Settings * const settings)
{
const Token * endOfVarScope = nullptr;
if (var->isLocal())
endOfVarScope = var->scope()->bodyEnd;
if (!endOfVarScope)
endOfVarScope = tok->scope()->bodyEnd;
if (std::any_of(values.begin(), values.end(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) {
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
values.remove_if(std::mem_fn(&ValueFlow::Value::isLifetimeValue));
}
if (!var->isPointer() && !var->isSmartPointer())
values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue));
if (tok->astParent()) {
for (std::list<ValueFlow::Value>::iterator it = values.begin(); it != values.end(); ++it) {
const std::string info = "Assignment '" + tok->astParent()->expressionString() + "', assigned value is " + it->infoString();
it->errorPath.emplace_back(tok, info);
}
}
if (tokenlist->isCPP() && Token::Match(var->typeStartToken(), "bool|_Bool")) {
std::list<ValueFlow::Value>::iterator it;
for (it = values.begin(); it != values.end(); ++it) {
if (it->isIntValue())
it->intvalue = (it->intvalue != 0);
if (it->isTokValue())
it ->intvalue = (it->tokvalue != nullptr);
}
}
// Static variable initialisation?
if (var->isStatic() && init)
lowerToPossible(values);
// Skip RHS
const Token * nextExpression = tok->astParent() ? nextAfterAstRightmostLeaf(tok->astParent()) : tok->next();
if (std::any_of(values.begin(), values.end(), std::mem_fn(&ValueFlow::Value::isTokValue))) {
std::list<ValueFlow::Value> tokvalues;
std::copy_if(values.begin(),
values.end(),
std::back_inserter(tokvalues),
std::mem_fn(&ValueFlow::Value::isTokValue));
valueFlowForwardVariable(const_cast<Token*>(nextExpression),
endOfVarScope,
var,
var->declarationId(),
tokvalues,
constValue,
false,
tokenlist,
errorLogger,
settings);
values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue));
}
for (ValueFlow::Value& value:values)
value.tokvalue = tok;
valueFlowForwardVariable(const_cast<Token*>(nextExpression),
endOfVarScope,
var,
var->declarationId(),
values,
constValue,
false,
tokenlist,
errorLogger,
settings);
}
static std::list<ValueFlow::Value> truncateValues(std::list<ValueFlow::Value> values, const ValueType *valueType, const Settings *settings)
{
if (!valueType || !valueType->isIntegral())
return values;
const size_t sz = ValueFlow::getSizeOf(*valueType, settings);
for (ValueFlow::Value &value : values) {
if (value.isFloatValue()) {
value.intvalue = value.floatValue;
value.valueType = ValueFlow::Value::INT;
}
if (value.isIntValue() && sz > 0 && sz < 8) {
const MathLib::biguint unsignedMaxValue = (1ULL << (sz * 8)) - 1ULL;
const MathLib::biguint signBit = 1ULL << (sz * 8 - 1);
value.intvalue &= unsignedMaxValue;
if (valueType->sign == ValueType::Sign::SIGNED && (value.intvalue & signBit))
value.intvalue |= ~unsignedMaxValue;
}
}
return values;
}
static bool isLiteralNumber(const Token *tok, bool cpp)
{
return tok->isNumber() || tok->isEnumerator() || tok->str() == "NULL" || (cpp && Token::Match(tok, "false|true|nullptr"));
}
static bool isVariableInit(const Token *tok)
{
return tok->str() == "(" &&
tok->isBinaryOp() &&
tok->astOperand1()->variable() &&
tok->astOperand1()->variable()->nameToken() == tok->astOperand1() &&
tok->astOperand1()->variable()->valueType() &&
tok->astOperand1()->variable()->valueType()->type >= ValueType::Type::VOID &&
!Token::simpleMatch(tok->astOperand2(), ",");
}
static void valueFlowAfterAssign(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope * scope : symboldatabase->functionScopes) {
std::set<int> aliased;
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
// Alias
if (tok->isUnaryOp("&")) {
aliased.insert(tok->astOperand1()->varId());
continue;
}
// Assignment
if ((tok->str() != "=" && !isVariableInit(tok)) || (tok->astParent()))
continue;
// Lhs should be a variable
if (!tok->astOperand1() || !tok->astOperand1()->varId())
continue;
const int varid = tok->astOperand1()->varId();
if (aliased.find(varid) != aliased.end())
continue;
const Variable *var = tok->astOperand1()->variable();
if (!var || (!var->isLocal() && !var->isGlobal() && !var->isArgument()))
continue;
// Rhs values..
if (!tok->astOperand2() || tok->astOperand2()->values().empty())
continue;
std::list<ValueFlow::Value> values = truncateValues(tok->astOperand2()->values(), tok->astOperand1()->valueType(), settings);
// Remove known values
std::set<ValueFlow::Value::ValueType> types;
if (tok->astOperand1()->hasKnownValue()) {
for (const ValueFlow::Value& value:tok->astOperand1()->values()) {
if (value.isKnown())
types.insert(value.valueType);
}
}
values.remove_if([&](const ValueFlow::Value& value) {
return types.count(value.valueType) > 0;
});
// Remove container size if its not a container
if (!astIsContainer(tok->astOperand2()))
values.remove_if([&](const ValueFlow::Value& value) {
return value.valueType == ValueFlow::Value::CONTAINER_SIZE;
});
if (values.empty())
continue;
const bool constValue = isLiteralNumber(tok->astOperand2(), tokenlist->isCPP());
const bool init = var->nameToken() == tok->astOperand1();
valueFlowForwardAssign(tok->astOperand2(), var, values, constValue, init, tokenlist, errorLogger, settings);
}
}
}
static void valueFlowSetConditionToKnown(const Token* tok, std::list<ValueFlow::Value>& values, bool then)
{
if (values.empty())
return;
if (then && !Token::Match(tok, "==|!|("))
return;
if (!then && !Token::Match(tok, "!=|%var%|("))
return;
if (isConditionKnown(tok, then))
changePossibleToKnown(values);
}
static bool isBreakScope(const Token* const endToken)
{
if (!Token::simpleMatch(endToken, "}"))
return false;
if (!Token::simpleMatch(endToken->link(), "{"))
return false;
return Token::findmatch(endToken->link(), "break|goto", endToken);
}
static ValueFlow::Value asImpossible(ValueFlow::Value v)
{
v.invertRange();
v.setImpossible();
return v;
}
static void insertImpossible(std::list<ValueFlow::Value>& values, const std::list<ValueFlow::Value>& input)
{
std::transform(input.begin(), input.end(), std::back_inserter(values), &asImpossible);
}
static void insertNegateKnown(std::list<ValueFlow::Value>& values, const std::list<ValueFlow::Value>& input)
{
for (ValueFlow::Value value:input) {
if (!value.isIntValue() && !value.isContainerSizeValue())
continue;
value.intvalue = !value.intvalue;
value.setKnown();
values.push_back(value);
}
}
static std::vector<const Variable*> getExprVariables(const Token* expr,
const TokenList* tokenlist,
const SymbolDatabase* symboldatabase,
const Settings* settings)
{
std::vector<const Variable*> result;
FwdAnalysis fwdAnalysis(tokenlist->isCPP(), settings->library);
std::set<int> varids = fwdAnalysis.getExprVarIds(expr);
std::transform(varids.begin(), varids.end(), std::back_inserter(result), [&](int id) {
return symboldatabase->getVariableFromVarId(id);
});
return result;
}
struct ValueFlowConditionHandler {
struct Condition {
const Token *vartok;
std::list<ValueFlow::Value> true_values;
std::list<ValueFlow::Value> false_values;
bool inverted = false;
Condition() : vartok(nullptr), true_values(), false_values(), inverted(false) {}
};
std::function<bool(Token* start, const Token* stop, const Token* exprTok, const std::list<ValueFlow::Value>& values, bool constValue)>
forward;
std::function<Condition(Token *tok)> parse;
void afterCondition(TokenList *tokenlist,
SymbolDatabase *symboldatabase,
ErrorLogger *errorLogger,
const Settings *settings) const {
for (const Scope *scope : symboldatabase->functionScopes) {
std::set<unsigned> aliased;
for (Token *tok = const_cast<Token *>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "if|while|for ("))
continue;
if (Token::Match(tok, "= & %var% ;"))
aliased.insert(tok->tokAt(2)->varId());
const Token* top = tok->astTop();
if (!top)
continue;
if (!Token::Match(top->previous(), "if|while|for (") && !Token::Match(tok->astParent(), "&&|%oror%"))
continue;
Condition cond = parse(tok);
if (!cond.vartok)
continue;
if (cond.vartok->variable() && cond.vartok->variable()->isVolatile())
continue;
if (cond.true_values.empty() || cond.false_values.empty())
continue;
if (exprDependsOnThis(cond.vartok))
continue;
std::vector<const Variable*> vars = getExprVariables(cond.vartok, tokenlist, symboldatabase, settings);
if (std::any_of(vars.begin(), vars.end(), [](const Variable* var) {
return !var;
}))
continue;
if (!vars.empty() && (vars.front()))
if (std::any_of(vars.begin(), vars.end(), [&](const Variable* var) {
return var && aliased.find(var->declarationId()) != aliased.end();
})) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
cond.vartok,
"variable is aliased so we just skip all valueflow after condition");
continue;
}
std::list<ValueFlow::Value> thenValues;
std::list<ValueFlow::Value> elseValues;
if (!Token::Match(tok, "!=|=|(|.") && tok != cond.vartok) {
thenValues.insert(thenValues.end(), cond.true_values.begin(), cond.true_values.end());
if (isConditionKnown(tok, false))
insertImpossible(elseValues, cond.false_values);
}
if (!Token::Match(tok, "==|!")) {
elseValues.insert(elseValues.end(), cond.false_values.begin(), cond.false_values.end());
if (isConditionKnown(tok, true)) {
insertImpossible(thenValues, cond.true_values);
if (Token::Match(tok, "(|.|%var%") && astIsBool(tok))
insertNegateKnown(thenValues, cond.true_values);
}
}
if (cond.inverted)
std::swap(thenValues, elseValues);
if (Token::Match(tok->astParent(), "%oror%|&&")) {
Token *parent = tok->astParent();
if (astIsRHS(tok) && parent->astParent() && parent->str() == parent->astParent()->str())
parent = parent->astParent();
else if (!astIsLHS(tok)) {
parent = nullptr;
}
if (parent) {
const std::string &op(parent->str());
std::list<ValueFlow::Value> values;
if (op == "&&")
values = thenValues;
else if (op == "||")
values = elseValues;
if (Token::Match(tok, "==|!="))
changePossibleToKnown(values);
if (!values.empty()) {
bool assign = false;
visitAstNodes(parent->astOperand2(), [&](Token* tok2) {
if (tok2 == tok)
return ChildrenToVisit::done;
if (isSameExpression(tokenlist->isCPP(), false, cond.vartok, tok2, settings->library, true, false))
setTokenValue(tok2, values.front(), settings);
else if (Token::Match(tok2, "++|--|=") && isSameExpression(tokenlist->isCPP(),
false,
cond.vartok,
tok2->astOperand1(),
settings->library,
true,
false)) {
assign = true;
return ChildrenToVisit::done;
}
return ChildrenToVisit::op1_and_op2;
});
if (assign)
break;
}
}
}
if (top && Token::Match(top->previous(), "if|while (") && !top->previous()->isExpandedMacro()) {
// does condition reassign variable?
if (tok != top->astOperand2() && Token::Match(top->astOperand2(), "%oror%|&&") &&
isVariablesChanged(top, top->link(), 0, vars, settings, tokenlist->isCPP())) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "assignment in condition");
continue;
}
// start token of conditional code
Token* startTokens[] = {nullptr, nullptr};
// if astParent is "!" we need to invert codeblock
{
const Token *tok2 = tok;
while (tok2->astParent()) {
const Token *parent = tok2->astParent();
while (parent && parent->str() == "&&")
parent = parent->astParent();
if (parent && (parent->str() == "!" || Token::simpleMatch(parent, "== false"))) {
std::swap(thenValues, elseValues);
}
tok2 = parent;
}
}
// determine startToken(s)
if (Token::simpleMatch(top->link(), ") {"))
startTokens[0] = top->link()->next();
if (Token::simpleMatch(top->link()->linkAt(1), "} else {"))
startTokens[1] = top->link()->linkAt(1)->tokAt(2);
int changeBlock = -1;
for (int i = 0; i < 2; i++) {
const Token *const startToken = startTokens[i];
if (!startToken)
continue;
std::list<ValueFlow::Value>& values = (i == 0 ? thenValues : elseValues);
valueFlowSetConditionToKnown(tok, values, i == 0);
// TODO: The endToken should not be startTokens[i]->link() in the valueFlowForwardVariable call
if (forward(startTokens[i], startTokens[i]->link(), cond.vartok, values, true))
changeBlock = i;
changeKnownToPossible(values);
}
// TODO: Values changed in noreturn blocks should not bail
if (changeBlock >= 0 && !Token::simpleMatch(top->previous(), "while (")) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
startTokens[changeBlock]->link(),
"valueFlowAfterCondition: " + cond.vartok->expressionString() +
" is changed in conditional block");
continue;
}
// After conditional code..
if (Token::simpleMatch(top->link(), ") {")) {
Token *after = top->link()->linkAt(1);
const Token* unknownFunction = nullptr;
bool dead_if = isReturnScope(after, &settings->library, &unknownFunction) ||
(tok->astParent() && Token::simpleMatch(tok->astParent()->previous(), "while (") &&
!isBreakScope(after));
bool dead_else = false;
if (!dead_if && unknownFunction) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope");
continue;
}
if (Token::simpleMatch(after, "} else {")) {
after = after->linkAt(2);
unknownFunction = nullptr;
dead_else = isReturnScope(after, &settings->library, &unknownFunction);
if (!dead_else && unknownFunction) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope");
continue;
}
}
if (dead_if && dead_else)
continue;
std::list<ValueFlow::Value> values;
if (dead_if) {
values = elseValues;
} else if (dead_else) {
values = thenValues;
} else {
std::copy_if(thenValues.begin(),
thenValues.end(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isPossible));
std::copy_if(elseValues.begin(),
elseValues.end(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isPossible));
}
if (!values.empty()) {
if ((dead_if || dead_else) && !Token::Match(tok->astParent(), "&&|&")) {
valueFlowSetConditionToKnown(tok, values, true);
valueFlowSetConditionToKnown(tok, values, false);
}
// TODO: constValue could be true if there are no assignments in the conditional blocks and
// perhaps if there are no && and no || in the condition
bool constValue = false;
forward(after, scope->bodyEnd, cond.vartok, values, constValue);
}
}
}
}
}
}
};
static void valueFlowAfterCondition(TokenList *tokenlist,
SymbolDatabase *symboldatabase,
ErrorLogger *errorLogger,
const Settings *settings)
{
ValueFlowConditionHandler handler;
handler.forward = [&](Token* start,
const Token* stop,
const Token* vartok,
const std::list<ValueFlow::Value>& values,
bool) {
valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings);
std::vector<const Variable*> vars = getExprVariables(vartok, tokenlist, symboldatabase, settings);
return isVariablesChanged(start, stop, 0, vars, settings, tokenlist->isCPP());
};
handler.parse = [&](const Token *tok) {
ValueFlowConditionHandler::Condition cond;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
const Token *vartok = parseCompareInt(tok, true_value, false_value);
if (vartok) {
if (vartok->str() == "=" && vartok->astOperand1() && vartok->astOperand2())
vartok = vartok->astOperand1();
cond.true_values.push_back(true_value);
cond.false_values.push_back(false_value);
cond.vartok = vartok;
return cond;
}
if (tok->str() == "!") {
vartok = tok->astOperand1();
} else if (tok->astParent() && (Token::Match(tok->astParent(), "%oror%|&&") ||
Token::Match(tok->astParent()->previous(), "if|while ("))) {
if (Token::simpleMatch(tok, "="))
vartok = tok->astOperand1();
else if (!Token::Match(tok, "%comp%|%assign%"))
vartok = tok;
}
if (!vartok)
return cond;
cond.true_values.emplace_back(tok, 0LL);
cond.false_values.emplace_back(tok, 0LL);
cond.vartok = vartok;
return cond;
};
handler.afterCondition(tokenlist, symboldatabase, errorLogger, settings);
}
static bool isInBounds(const ValueFlow::Value& value, MathLib::bigint x)
{
if (value.intvalue == x)
return true;
if (value.bound == ValueFlow::Value::Bound::Lower && value.intvalue > x)
return false;
if (value.bound == ValueFlow::Value::Bound::Upper && value.intvalue < x)
return false;
// Checking for equality is not necessary since we already know the value is not equal
if (value.bound == ValueFlow::Value::Bound::Point)
return false;
return true;
}
static const ValueFlow::Value* getCompareIntValue(const std::list<ValueFlow::Value>& values, std::function<bool(MathLib::bigint, MathLib::bigint)> compare)
{
const ValueFlow::Value* result = nullptr;
for (const ValueFlow::Value& value : values) {
if (!value.isIntValue())
continue;
if (result)
result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) {
return compare(x.intvalue, y.intvalue);
});
else
result = &value;
}
return result;
}
static const ValueFlow::Value* proveLessThan(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
{
const ValueFlow::Value* result = nullptr;
const ValueFlow::Value* maxValue = getCompareIntValue(values, std::greater<MathLib::bigint> {});
if (maxValue && maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower) {
if (maxValue->intvalue <= x)
result = maxValue;
}
return result;
}
static const ValueFlow::Value* proveGreaterThan(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
{
const ValueFlow::Value* result = nullptr;
const ValueFlow::Value* minValue = getCompareIntValue(values, std::less<MathLib::bigint> {});
if (minValue && minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper) {
if (minValue->intvalue >= x)
result = minValue;
}
return result;
}
static const ValueFlow::Value* proveNotEqual(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
{
const ValueFlow::Value* result = nullptr;
for (const ValueFlow::Value& value : values) {
if (value.valueType != ValueFlow::Value::INT)
continue;
if (result && !isInBounds(value, result->intvalue))
continue;
if (value.isImpossible()) {
if (value.intvalue == x)
return &value;
if (!isInBounds(value, x))
continue;
result = &value;
} else {
if (value.intvalue == x)
return nullptr;
if (!isInBounds(value, x))
continue;
result = nullptr;
}
}
return result;
}
static void valueFlowInferCondition(TokenList* tokenlist,
const Settings* settings)
{
for (Token* tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->astParent())
continue;
if (tok->hasKnownValue())
continue;
if (tok->variable() && (Token::Match(tok->astParent(), "?|&&|!|%oror%") ||
Token::Match(tok->astParent()->previous(), "if|while ("))) {
const ValueFlow::Value* result = proveNotEqual(tok->values(), 0);
if (!result)
continue;
ValueFlow::Value value = *result;
value.intvalue = 1;
value.bound = ValueFlow::Value::Bound::Point;
value.setKnown();
setTokenValue(tok, value, settings);
} else if (tok->isComparisonOp()) {
MathLib::bigint val = 0;
const Token* varTok = nullptr;
std::string op = tok->str();
if (tok->astOperand1()->hasKnownIntValue()) {
val = tok->astOperand1()->values().front().intvalue;
varTok = tok->astOperand2();
// Flip the operator
if (op == ">")
op = "<";
else if (op == "<")
op = ">";
else if (op == ">=")
op = "<=";
else if (op == "<=")
op = ">=";
} else if (tok->astOperand2()->hasKnownIntValue()) {
val = tok->astOperand2()->values().front().intvalue;
varTok = tok->astOperand1();
}
if (!varTok)
continue;
if (varTok->hasKnownIntValue())
continue;
if (varTok->values().empty())
continue;
const ValueFlow::Value* result = nullptr;
bool known = false;
if (op == "==" || op == "!=") {
result = proveNotEqual(varTok->values(), val);
known = op == "!=";
} else if (op == "<" || op == ">=") {
result = proveLessThan(varTok->values(), val);
known = op == "<";
if (!result && !isSaturated(val)) {
result = proveGreaterThan(varTok->values(), val - 1);
known = op == ">=";
}
} else if (op == ">" || op == "<=") {
result = proveGreaterThan(varTok->values(), val);
known = op == ">";
if (!result && !isSaturated(val)) {
result = proveLessThan(varTok->values(), val + 1);
known = op == "<=";
}
}
if (!result)
continue;
ValueFlow::Value value = *result;
value.intvalue = known;
value.bound = ValueFlow::Value::Bound::Point;
value.setKnown();
setTokenValue(tok, value, settings);
}
}
}
static bool valueFlowForLoop2(const Token *tok,
ProgramMemory *memory1,
ProgramMemory *memory2,
ProgramMemory *memoryAfter)
{
// for ( firstExpression ; secondExpression ; thirdExpression )
const Token *firstExpression = tok->next()->astOperand2()->astOperand1();
const Token *secondExpression = tok->next()->astOperand2()->astOperand2()->astOperand1();
const Token *thirdExpression = tok->next()->astOperand2()->astOperand2()->astOperand2();
ProgramMemory programMemory;
MathLib::bigint result(0);
bool error = false;
execute(firstExpression, &programMemory, &result, &error);
if (error)
return false;
execute(secondExpression, &programMemory, &result, &error);
if (result == 0) // 2nd expression is false => no looping
return false;
if (error) {
// If a variable is reassigned in second expression, return false
bool reassign = false;
visitAstNodes(secondExpression,
[&](const Token *t) {
if (t->str() == "=" && t->astOperand1() && programMemory.hasValue(t->astOperand1()->varId()))
// TODO: investigate what variable is assigned.
reassign = true;
return reassign ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2;
});
if (reassign)
return false;
}
ProgramMemory startMemory(programMemory);
ProgramMemory endMemory;
int maxcount = 10000;
while (result != 0 && !error && --maxcount > 0) {
endMemory = programMemory;
execute(thirdExpression, &programMemory, &result, &error);
if (!error)
execute(secondExpression, &programMemory, &result, &error);
}
memory1->swap(startMemory);
if (!error) {
memory2->swap(endMemory);
memoryAfter->swap(programMemory);
}
return true;
}
static void valueFlowForLoopSimplify(Token * const bodyStart, const nonneg int varid, bool globalvar, 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, globalvar, settings, tokenlist->isCPP()))
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->str() == "?") {
if (parent->astOperand2() != p)
parent = nullptr;
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, settings);
}
if (Token::Match(tok2, "%oror%|&&")) {
const ProgramMemory programMemory(getProgramMemory(tok2->astTop(), varid, ValueFlow::Value(value)));
if ((tok2->str() == "&&" && !conditionIsTrue(tok2->astOperand1(), programMemory)) ||
(tok2->str() == "||" && !conditionIsFalse(tok2->astOperand1(), programMemory))) {
// Skip second expression..
const Token *parent = tok2;
while (parent && parent->str() == tok2->str())
parent = parent->astParent();
// Jump to end of condition
if (parent && parent->str() == "(") {
tok2 = parent->link();
// cast
if (Token::simpleMatch(tok2, ") ("))
tok2 = tok2->linkAt(1);
}
}
}
if ((tok2->str() == "&&" && conditionIsFalse(tok2->astOperand1(), getProgramMemory(tok2->astTop(), varid, ValueFlow::Value(value)))) ||
(tok2->str() == "||" && conditionIsTrue(tok2->astOperand1(), getProgramMemory(tok2->astTop(), varid, ValueFlow::Value(value)))))
break;
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);
}
}
else if (Token::simpleMatch(tok2, ") {")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop skipping {} code");
tok2 = tok2->linkAt(1);
if (Token::simpleMatch(tok2, "} else {"))
tok2 = tok2->linkAt(2);
}
}
}
static void valueFlowForLoopSimplifyAfter(Token *fortok, nonneg int varid, const MathLib::bigint num, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
const Token *vartok = nullptr;
for (const Token *tok = fortok; tok; tok = tok->next()) {
if (tok->varId() == varid) {
vartok = tok;
break;
}
}
if (!vartok || !vartok->variable())
return;
const Variable *var = vartok->variable();
const Token *endToken = nullptr;
if (var->isLocal())
endToken = var->scope()->bodyEnd;
else
endToken = fortok->scope()->bodyEnd;
Token* blockTok = fortok->linkAt(1)->linkAt(1);
std::list<ValueFlow::Value> values;
values.emplace_back(num);
values.back().errorPath.emplace_back(fortok,"After for loop, " + var->name() + " has value " + values.back().infoString());
if (blockTok != endToken) {
valueFlowForwardVariable(
blockTok->next(), endToken, var, varid, values, false, false, tokenlist, errorLogger, settings);
}
}
static void valueFlowForLoop(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope &scope : symboldatabase->scopeList) {
if (scope.type != Scope::eFor)
continue;
Token* tok = const_cast<Token*>(scope.classDef);
Token* const bodyStart = const_cast<Token*>(scope.bodyStart);
if (!Token::simpleMatch(tok->next()->astOperand2(), ";") ||
!Token::simpleMatch(tok->next()->astOperand2()->astOperand2(), ";"))
continue;
nonneg int varid;
bool knownInitValue, partialCond;
MathLib::bigint initValue, stepValue, lastValue;
if (extractForLoopValues(tok, &varid, &knownInitValue, &initValue, &partialCond, &stepValue, &lastValue)) {
const bool executeBody = !knownInitValue || initValue <= lastValue;
if (executeBody) {
valueFlowForLoopSimplify(bodyStart, varid, false, initValue, tokenlist, errorLogger, settings);
if (stepValue == 1)
valueFlowForLoopSimplify(bodyStart, varid, false, lastValue, tokenlist, errorLogger, settings);
}
const MathLib::bigint afterValue = executeBody ? lastValue + stepValue : initValue;
valueFlowForLoopSimplifyAfter(tok, varid, afterValue, tokenlist, errorLogger, settings);
} else {
ProgramMemory mem1, mem2, memAfter;
if (valueFlowForLoop2(tok, &mem1, &mem2, &memAfter)) {
ProgramMemory::Map::const_iterator it;
for (it = mem1.values.begin(); it != mem1.values.end(); ++it) {
if (!it->second.isIntValue())
continue;
valueFlowForLoopSimplify(bodyStart, it->first, false, it->second.intvalue, tokenlist, errorLogger, settings);
}
for (it = mem2.values.begin(); it != mem2.values.end(); ++it) {
if (!it->second.isIntValue())
continue;
valueFlowForLoopSimplify(bodyStart, it->first, false, it->second.intvalue, tokenlist, errorLogger, settings);
}
for (it = memAfter.values.begin(); it != memAfter.values.end(); ++it) {
if (!it->second.isIntValue())
continue;
valueFlowForLoopSimplifyAfter(tok, it->first, it->second.intvalue, tokenlist, errorLogger, settings);
}
}
}
}
}
struct MultiValueFlowForwardAnalyzer : ValueFlowForwardAnalyzer {
std::unordered_map<nonneg int, ValueFlow::Value> values;
std::unordered_map<nonneg int, const Variable*> vars;
MultiValueFlowForwardAnalyzer()
: ValueFlowForwardAnalyzer(), values(), vars()
{}
MultiValueFlowForwardAnalyzer(const std::unordered_map<const Variable*, ValueFlow::Value>& args, const TokenList* t)
: ValueFlowForwardAnalyzer(t), values(), vars() {
for (const auto& p:args) {
values[p.first->declarationId()] = p.second;
vars[p.first->declarationId()] = p.first;
}
}
virtual const std::unordered_map<nonneg int, const Variable*>& getVars() const {
return vars;
}
virtual const ValueFlow::Value* getValue(const Token* tok) const OVERRIDE {
if (tok->varId() == 0)
return nullptr;
auto it = values.find(tok->varId());
if (it == values.end())
return nullptr;
return &it->second;
}
virtual ValueFlow::Value* getValue(const Token* tok) OVERRIDE {
if (tok->varId() == 0)
return nullptr;
auto it = values.find(tok->varId());
if (it == values.end())
return nullptr;
return &it->second;
}
virtual void makeConditional() OVERRIDE {
for (auto&& p:values) {
p.second.conditional = true;
}
}
virtual void addErrorPath(const Token* tok, const std::string& s) OVERRIDE {
for (auto&& p:values) {
p.second.errorPath.emplace_back(tok, "Assuming condition is " + s);
}
}
virtual bool isAlias(const Token* tok) const OVERRIDE {
std::list<ValueFlow::Value> vals;
std::transform(values.begin(), values.end(), std::back_inserter(vals), SelectMapValues{});
for (const auto& p:getVars()) {
nonneg int varid = p.first;
const Variable* var = p.second;
if (tok->varId() == varid)
return true;
if (isAliasOf(var, tok, varid, vals))
return true;
}
return false;
}
virtual bool isGlobal() const OVERRIDE {
return false;
}
virtual bool lowerToPossible() OVERRIDE {
for (auto&& p:values) {
if (p.second.isImpossible())
return false;
p.second.changeKnownToPossible();
}
return true;
}
virtual bool lowerToInconclusive() OVERRIDE {
for (auto&& p:values) {
if (p.second.isImpossible())
return false;
p.second.setInconclusive();
}
return true;
}
virtual bool isConditional() const OVERRIDE {
for (auto&& p:values) {
if (p.second.conditional)
return true;
if (p.second.condition)
return !p.second.isImpossible();
}
return false;
}
virtual bool updateScope(const Token* endBlock, bool) const OVERRIDE {
const Scope* scope = endBlock->scope();
if (!scope)
return false;
if (scope->type == Scope::eLambda) {
for (const auto& p:values) {
if (!p.second.isLifetimeValue())
return false;
}
return true;
} else if (scope->type == Scope::eIf || scope->type == Scope::eElse || scope->type == Scope::eWhile ||
scope->type == Scope::eFor) {
auto pred = [](const ValueFlow::Value& value) {
if (value.isKnown())
return true;
if (value.isImpossible())
return true;
if (value.isLifetimeValue())
return true;
return false;
};
if (std::all_of(values.begin(), values.end(), std::bind(pred, std::bind(SelectMapValues{}, std::placeholders::_1))))
return true;
if (isConditional())
return false;
const Token* condTok = getCondTokFromEnd(endBlock);
std::set<nonneg int> varids;
std::transform(getVars().begin(), getVars().end(), std::inserter(varids, varids.begin()), SelectMapKeys{});
return bifurcate(condTok, varids, getSettings());
}
return false;
}
virtual bool match(const Token* tok) const OVERRIDE {
return values.count(tok->varId()) > 0;
}
virtual ProgramState getProgramState() const OVERRIDE {
ProgramState ps;
for (const auto& p:values)
ps[p.first] = p.second;
return ps;
}
};
static void valueFlowInjectParameter(TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings, const Scope* functionScope, const std::unordered_map<const Variable*, std::list<ValueFlow::Value>>& vars)
{
using Args = std::vector<std::unordered_map<const Variable*, ValueFlow::Value>>;
Args args(1);
// Compute cartesian product of all arguments
for (const auto& p:vars) {
if (p.second.empty())
continue;
args.back()[p.first] = p.second.front();
}
for (const auto& p:vars) {
if (args.size() > 256) {
std::string fname = "<unknown>";
Function* f = functionScope->function;
if (f)
fname = f->name();
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, functionScope->bodyStart, "Too many argument passed to " + fname);
break;
}
std::for_each(std::next(p.second.begin()), p.second.end(), [&](const ValueFlow::Value& value) {
Args new_args;
for (auto arg:args) {
if (value.path != 0) {
for (const auto& q:arg) {
if (q.second.path == 0)
continue;
if (q.second.path != value.path)
return;
}
}
arg[p.first] = value;
new_args.push_back(arg);
}
std::copy(new_args.begin(), new_args.end(), std::back_inserter(args));
});
}
for (const auto& arg:args) {
if (arg.empty())
continue;
bool skip = false;
// Make sure all arguments are the same path
MathLib::bigint path = arg.begin()->second.path;
for (const auto& p:arg) {
if (p.second.path != path) {
skip = true;
break;
}
}
if (skip)
continue;
MultiValueFlowForwardAnalyzer a(arg, tokenlist);
valueFlowGenericForward(const_cast<Token*>(functionScope->bodyStart), functionScope->bodyEnd, a, settings);
}
}
static void valueFlowInjectParameter(TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings, const Variable* arg, const Scope* functionScope, const std::list<ValueFlow::Value>& argvalues)
{
// Is argument passed by value or const reference, and is it a known non-class type?
if (arg->isReference() && !arg->isConst() && !arg->isClass())
return;
// Set value in function scope..
const int varid2 = arg->declarationId();
if (!varid2)
return;
valueFlowForwardVariable(const_cast<Token*>(functionScope->bodyStart->next()),
functionScope->bodyEnd,
arg,
varid2,
argvalues,
false,
true,
tokenlist,
errorLogger,
settings);
}
static void valueFlowSwitchVariable(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope &scope : symboldatabase->scopeList) {
if (scope.type != Scope::ScopeType::eSwitch)
continue;
if (!Token::Match(scope.classDef, "switch ( %var% ) {"))
continue;
const Token *vartok = scope.classDef->tokAt(2);
const Variable *var = vartok->variable();
if (!var)
continue;
// bailout: global non-const variables
if (!(var->isLocal() || var->isArgument()) && !var->isConst()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, vartok, "switch variable " + var->name() + " is global");
continue;
}
for (Token *tok = scope.bodyStart->next(); tok != scope.bodyEnd; tok = tok->next()) {
if (tok->str() == "{") {
tok = tok->link();
continue;
}
if (Token::Match(tok, "case %num% :")) {
std::list<ValueFlow::Value> values;
values.emplace_back(MathLib::toLongNumber(tok->next()->str()));
values.back().condition = tok;
const std::string info("case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here.");
values.back().errorPath.emplace_back(tok, info);
bool known = false;
if ((Token::simpleMatch(tok->previous(), "{") || Token::simpleMatch(tok->tokAt(-2), "break ;")) && !Token::Match(tok->tokAt(3), ";| case"))
known = true;
while (Token::Match(tok->tokAt(3), ";| case %num% :")) {
known = false;
tok = tok->tokAt(3);
if (!tok->isName())
tok = tok->next();
values.emplace_back(MathLib::toLongNumber(tok->next()->str()));
values.back().condition = tok;
const std::string info2("case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here.");
values.back().errorPath.emplace_back(tok, info2);
}
for (std::list<ValueFlow::Value>::const_iterator val = values.begin(); val != values.end(); ++val) {
valueFlowReverse(tokenlist,
const_cast<Token*>(scope.classDef),
vartok,
*val,
ValueFlow::Value(),
errorLogger,
settings);
}
if (vartok->variable()->scope()) {
if (known)
values.back().setKnown();
// FIXME We must check if there is a return. See #9276
/*
valueFlowForwardVariable(tok->tokAt(3),
vartok->variable()->scope()->bodyEnd,
vartok->variable(),
vartok->varId(),
values,
values.back().isKnown(),
false,
tokenlist,
errorLogger,
settings);
*/
}
}
}
}
}
static void setTokenValues(Token *tok, const std::list<ValueFlow::Value> &values, const Settings *settings)
{
for (const ValueFlow::Value &value : values) {
if (value.isIntValue())
setTokenValue(tok, value, settings);
}
}
static bool evaluate(const Token *expr, const std::vector<std::list<ValueFlow::Value>> &values, std::list<ValueFlow::Value> *result)
{
if (!expr)
return false;
// strlen(arg)..
if (expr->str() == "(" && Token::Match(expr->previous(), "strlen ( %name% )")) {
const Token *arg = expr->next();
if (arg->str().compare(0,3,"arg") != 0 || arg->str().size() != 4)
return false;
const char n = arg->str()[3];
if (n < '1' || n - '1' >= values.size())
return false;
for (const ValueFlow::Value &argvalue : values[n - '1']) {
if (argvalue.isTokValue() && argvalue.tokvalue->tokType() == Token::eString) {
ValueFlow::Value res(argvalue); // copy all "inconclusive", "condition", etc attributes
// set return value..
res.valueType = ValueFlow::Value::INT;
res.tokvalue = nullptr;
res.intvalue = Token::getStrLength(argvalue.tokvalue);
result->emplace_back(std::move(res));
}
}
return !result->empty();
}
// unary operands
if (expr->astOperand1() && !expr->astOperand2()) {
std::list<ValueFlow::Value> opvalues;
if (!evaluate(expr->astOperand1(), values, &opvalues))
return false;
if (expr->str() == "+") {
result->swap(opvalues);
return true;
}
if (expr->str() == "-") {
for (ValueFlow::Value v: opvalues) {
if (v.isIntValue()) {
v.intvalue = -v.intvalue;
result->emplace_back(std::move(v));
}
}
return true;
}
return false;
}
// binary/ternary operands
if (expr->astOperand1() && expr->astOperand2()) {
std::list<ValueFlow::Value> lhsValues, rhsValues;
if (!evaluate(expr->astOperand1(), values, &lhsValues))
return false;
if (expr->str() != "?" && !evaluate(expr->astOperand2(), values, &rhsValues))
return false;
for (const ValueFlow::Value &val1 : lhsValues) {
if (!val1.isIntValue())
continue;
if (expr->str() == "?") {
rhsValues.clear();
const Token *expr2 = val1.intvalue ? expr->astOperand2()->astOperand1() : expr->astOperand2()->astOperand2();
if (!evaluate(expr2, values, &rhsValues))
continue;
result->insert(result->end(), rhsValues.begin(), rhsValues.end());
continue;
}
for (const ValueFlow::Value &val2 : rhsValues) {
if (!val2.isIntValue())
continue;
if (val1.varId != 0 && val2.varId != 0) {
if (val1.varId != val2.varId || val1.varvalue != val2.varvalue)
continue;
}
if (expr->str() == "+")
result->emplace_back(ValueFlow::Value(val1.intvalue + val2.intvalue));
else if (expr->str() == "-")
result->emplace_back(ValueFlow::Value(val1.intvalue - val2.intvalue));
else if (expr->str() == "*")
result->emplace_back(ValueFlow::Value(val1.intvalue * val2.intvalue));
else if (expr->str() == "/" && val2.intvalue != 0)
result->emplace_back(ValueFlow::Value(val1.intvalue / val2.intvalue));
else if (expr->str() == "%" && val2.intvalue != 0)
result->emplace_back(ValueFlow::Value(val1.intvalue % val2.intvalue));
else if (expr->str() == "&")
result->emplace_back(ValueFlow::Value(val1.intvalue & val2.intvalue));
else if (expr->str() == "|")
result->emplace_back(ValueFlow::Value(val1.intvalue | val2.intvalue));
else if (expr->str() == "^")
result->emplace_back(ValueFlow::Value(val1.intvalue ^ val2.intvalue));
else if (expr->str() == "==")
result->emplace_back(ValueFlow::Value(val1.intvalue == val2.intvalue));
else if (expr->str() == "!=")
result->emplace_back(ValueFlow::Value(val1.intvalue != val2.intvalue));
else if (expr->str() == "<")
result->emplace_back(ValueFlow::Value(val1.intvalue < val2.intvalue));
else if (expr->str() == ">")
result->emplace_back(ValueFlow::Value(val1.intvalue > val2.intvalue));
else if (expr->str() == ">=")
result->emplace_back(ValueFlow::Value(val1.intvalue >= val2.intvalue));
else if (expr->str() == "<=")
result->emplace_back(ValueFlow::Value(val1.intvalue <= val2.intvalue));
else if (expr->str() == "&&")
result->emplace_back(ValueFlow::Value(val1.intvalue && val2.intvalue));
else if (expr->str() == "||")
result->emplace_back(ValueFlow::Value(val1.intvalue || val2.intvalue));
else if (expr->str() == "<<")
result->emplace_back(ValueFlow::Value(val1.intvalue << val2.intvalue));
else if (expr->str() == ">>")
result->emplace_back(ValueFlow::Value(val1.intvalue >> val2.intvalue));
else
return false;
combineValueProperties(val1, val2, &result->back());
}
}
return !result->empty();
}
if (expr->str().compare(0,3,"arg")==0) {
*result = values[expr->str()[3] - '1'];
return true;
}
if (expr->isNumber()) {
result->emplace_back(ValueFlow::Value(MathLib::toLongNumber(expr->str())));
result->back().setKnown();
return true;
} else if (expr->tokType() == Token::eChar) {
result->emplace_back(ValueFlow::Value(MathLib::toLongNumber(expr->str())));
result->back().setKnown();
return true;
}
return false;
}
static std::list<ValueFlow::Value> getFunctionArgumentValues(const Token *argtok)
{
std::list<ValueFlow::Value> argvalues(argtok->values());
removeImpossible(argvalues);
if (argvalues.empty() && Token::Match(argtok, "%comp%|%oror%|&&|!")) {
argvalues.emplace_back(0);
argvalues.emplace_back(1);
}
return argvalues;
}
static void valueFlowLibraryFunction(Token *tok, const std::string &returnValue, const Settings *settings)
{
std::vector<std::list<ValueFlow::Value>> argValues;
for (const Token *argtok : getArguments(tok->previous())) {
argValues.emplace_back(getFunctionArgumentValues(argtok));
if (argValues.back().empty())
return;
}
if (returnValue.find("arg") != std::string::npos && argValues.empty())
return;
TokenList tokenList(settings);
{
const std::string code = "return " + returnValue + ";";
std::istringstream istr(code);
if (!tokenList.createTokens(istr))
return;
}
// combine operators, set links, etc..
std::stack<Token *> lpar;
for (Token *tok2 = tokenList.front(); tok2; tok2 = tok2->next()) {
if (Token::Match(tok2, "[!<>=] =")) {
tok2->str(tok2->str() + "=");
tok2->deleteNext();
} else if (tok2->str() == "(")
lpar.push(tok2);
else if (tok2->str() == ")") {
if (lpar.empty())
return;
Token::createMutualLinks(lpar.top(), tok2);
lpar.pop();
}
}
if (!lpar.empty())
return;
// Evaluate expression
tokenList.createAst();
std::list<ValueFlow::Value> results;
if (evaluate(tokenList.front()->astOperand1(), argValues, &results))
setTokenValues(tok, results, settings);
}
static void valueFlowSubFunction(TokenList* tokenlist, SymbolDatabase* symboldatabase, ErrorLogger* errorLogger, const Settings* settings)
{
for (const Scope* scope : symboldatabase->functionScopes) {
const Function* function = scope->function;
if (!function)
continue;
int id = 0;
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "%name% ("))
continue;
const Function * const calledFunction = tok->function();
if (!calledFunction) {
// library function?
const std::string& returnValue(settings->library.returnValue(tok));
if (!returnValue.empty())
valueFlowLibraryFunction(tok->next(), returnValue, settings);
continue;
}
const Scope * const calledFunctionScope = calledFunction->functionScope;
if (!calledFunctionScope)
continue;
id++;
std::unordered_map<const Variable*, std::list<ValueFlow::Value>> argvars;
// TODO: Rewrite this. It does not work well to inject 1 argument at a time.
const std::vector<const Token *> &callArguments = getArguments(tok);
for (int argnr = 0U; argnr < callArguments.size(); ++argnr) {
const Token *argtok = callArguments[argnr];
// Get function argument
const Variable * const argvar = calledFunction->getArgumentVar(argnr);
if (!argvar)
break;
// passing value(s) to function
std::list<ValueFlow::Value> argvalues(getFunctionArgumentValues(argtok));
// Don't forward container sizes for now since programmemory can't evaluate conditions
argvalues.remove_if(std::mem_fn(&ValueFlow::Value::isContainerSizeValue));
if (argvalues.empty())
continue;
// Error path..
for (ValueFlow::Value &v : argvalues) {
const std::string nr = MathLib::toString(argnr + 1) + getOrdinalText(argnr + 1);
v.errorPath.emplace_back(argtok,
"Calling function '" +
calledFunction->name() +
"', " +
nr +
" argument '" +
argtok->expressionString() +
"' value is " +
v.infoString());
v.path = 256 * v.path + id;
// Change scope of lifetime values
if (v.isLifetimeValue())
v.lifetimeScope = ValueFlow::Value::LifetimeScope::SubFunction;
}
// passed values are not "known"..
lowerToPossible(argvalues);
argvars[argvar] = argvalues;
}
valueFlowInjectParameter(tokenlist, errorLogger, settings, calledFunctionScope, argvars);
}
}
}
static void valueFlowFunctionDefaultParameter(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
if (!tokenlist->isCPP())
return;
for (const Scope* scope : symboldatabase->functionScopes) {
const Function* function = scope->function;
if (!function)
continue;
for (std::size_t arg = function->minArgCount(); arg < function->argCount(); arg++) {
const Variable* var = function->getArgumentVar(arg);
if (var && var->hasDefault() && Token::Match(var->nameToken(), "%var% = %num%|%str% [,)]")) {
const std::list<ValueFlow::Value> &values = var->nameToken()->tokAt(2)->values();
std::list<ValueFlow::Value> argvalues;
for (const ValueFlow::Value &value : values) {
ValueFlow::Value v(value);
v.defaultArg = true;
v.changeKnownToPossible();
if (v.isPossible())
argvalues.push_back(v);
}
if (!argvalues.empty())
valueFlowInjectParameter(tokenlist, errorLogger, settings, var, scope, argvalues);
}
}
}
}
static bool isKnown(const Token * tok)
{
return tok && tok->hasKnownIntValue();
}
static void valueFlowFunctionReturn(TokenList *tokenlist, ErrorLogger *errorLogger)
{
for (Token *tok = tokenlist->back(); tok; tok = tok->previous()) {
if (tok->str() != "(" || !tok->astOperand1() || !tok->astOperand1()->function())
continue;
if (tok->hasKnownValue())
continue;
// Arguments..
std::vector<MathLib::bigint> parvalues;
if (tok->astOperand2()) {
const Token *partok = tok->astOperand2();
while (partok && partok->str() == "," && isKnown(partok->astOperand2()))
partok = partok->astOperand1();
if (!isKnown(partok))
continue;
parvalues.push_back(partok->values().front().intvalue);
partok = partok->astParent();
while (partok && partok->str() == ",") {
parvalues.push_back(partok->astOperand2()->values().front().intvalue);
partok = partok->astParent();
}
if (partok != tok)
continue;
}
// Get scope and args of function
const Function * const function = tok->astOperand1()->function();
const Scope * const functionScope = function->functionScope;
if (!functionScope || !Token::simpleMatch(functionScope->bodyStart, "{ return")) {
if (functionScope && tokenlist->getSettings()->debugwarnings && Token::findsimplematch(functionScope->bodyStart, "return", functionScope->bodyEnd))
bailout(tokenlist, errorLogger, tok, "function return; nontrivial function body");
continue;
}
ProgramMemory programMemory;
for (std::size_t i = 0; i < parvalues.size(); ++i) {
const Variable * const arg = function->getArgumentVar(i);
if (!arg || !Token::Match(arg->typeStartToken(), "%type% %name% ,|)")) {
if (tokenlist->getSettings()->debugwarnings)
bailout(tokenlist, errorLogger, tok, "function return; unhandled argument type");
programMemory.clear();
break;
}
programMemory.setIntValue(arg->declarationId(), parvalues[i]);
}
if (programMemory.empty() && !parvalues.empty())
continue;
// Determine return value of subfunction..
MathLib::bigint result = 0;
bool error = false;
execute(functionScope->bodyStart->next()->astOperand1(),
&programMemory,
&result,
&error);
if (!error) {
ValueFlow::Value v(result);
if (function->hasVirtualSpecifier())
v.setPossible();
else
v.setKnown();
setTokenValue(tok, v, tokenlist->getSettings());
}
}
}
static void valueFlowUninit(TokenList *tokenlist, SymbolDatabase * /*symbolDatabase*/, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!Token::Match(tok,"[;{}] %type%"))
continue;
if (!tok->scope()->isExecutable())
continue;
const Token *vardecl = tok->next();
bool stdtype = false;
bool pointer = false;
while (Token::Match(vardecl, "%name%|::|*") && vardecl->varId() == 0) {
stdtype |= vardecl->isStandardType();
pointer |= vardecl->str() == "*";
vardecl = vardecl->next();
}
// if (!stdtype && !pointer)
// continue;
if (!Token::Match(vardecl, "%var% ;"))
continue;
if (Token::Match(vardecl, "%varid% ; %varid% =", vardecl->varId()))
continue;
const Variable *var = vardecl->variable();
if (!var || var->nameToken() != vardecl)
continue;
if ((!var->isPointer() && var->type() && var->type()->needInitialization != Type::NeedInitialization::True) ||
!var->isLocal() || var->isStatic() || var->isExtern() || var->isReference() || var->isThrow())
continue;
if (!var->type() && !stdtype && !pointer)
continue;
ValueFlow::Value uninitValue;
uninitValue.setKnown();
uninitValue.valueType = ValueFlow::Value::UNINIT;
uninitValue.tokvalue = vardecl;
std::list<ValueFlow::Value> values;
values.push_back(uninitValue);
const bool constValue = true;
const bool subFunction = false;
valueFlowForwardVariable(vardecl->next(),
vardecl->scope()->bodyEnd,
var,
vardecl->varId(),
values,
constValue,
subFunction,
tokenlist,
errorLogger,
settings);
}
}
static bool hasContainerSizeGuard(const Token *tok, nonneg int containerId)
{
for (; tok && tok->astParent(); tok = tok->astParent()) {
const Token *parent = tok->astParent();
if (tok != parent->astOperand2())
continue;
if (!Token::Match(parent, "%oror%|&&|?"))
continue;
// is container found in lhs?
bool found = false;
visitAstNodes(parent->astOperand1(),
[&](const Token *t) {
if (t->varId() == containerId)
found = true;
return found ? ChildrenToVisit::done : ChildrenToVisit::op1_and_op2;
});
if (found)
return true;
}
return false;
}
static bool isContainerSize(const Token* tok)
{
if (!Token::Match(tok, "%var% . %name% ("))
return false;
if (!astIsContainer(tok))
return false;
if (tok->valueType()->container && tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::SIZE)
return true;
if (Token::Match(tok->tokAt(2), "size|length ( )"))
return true;
return false;
}
static bool isContainerEmpty(const Token* tok)
{
if (!Token::Match(tok, "%var% . %name% ("))
return false;
if (!astIsContainer(tok))
return false;
if (tok->valueType()->container && tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::EMPTY)
return true;
if (Token::simpleMatch(tok->tokAt(2), "empty ( )"))
return true;
return false;
}
static bool isContainerSizeChanged(const Token *tok, int depth=20);
static bool isContainerSizeChanged(nonneg int varId, const Token *start, const Token *end, int depth = 20);
static bool isContainerSizeChangedByFunction(const Token *tok, int depth = 20)
{
if (!tok->valueType() || !tok->valueType()->container)
return false;
// If we are accessing an element then we are not changing the container size
if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Yield yield = tok->valueType()->container->getYield(tok->strAt(2));
if (yield != Library::Container::Yield::NO_YIELD)
return false;
}
if (Token::simpleMatch(tok->astParent(), "["))
return false;
// address of variable
const bool addressOf = tok->valueType()->pointer || (tok->astParent() && tok->astParent()->isUnaryOp("&"));
int narg;
const Token * ftok = getTokenArgumentFunction(tok, narg);
if (!ftok)
return false; // not a function => variable not changed
const Function * fun = ftok->function();
if (fun) {
const Variable *arg = fun->getArgumentVar(narg);
if (arg) {
if (!arg->isReference() && !addressOf)
return false;
if (!addressOf && arg->isConst())
return false;
if (arg->valueType() && arg->valueType()->constness == 1)
return false;
const Scope * scope = fun->functionScope;
if (scope) {
// Argument not used
if (!arg->nameToken())
return false;
if (depth > 0)
return isContainerSizeChanged(arg->declarationId(), scope->bodyStart, scope->bodyEnd, depth - 1);
}
// Don't know => Safe guess
return true;
}
}
bool inconclusive = false;
const bool isChanged = isVariableChangedByFunctionCall(tok, 0, nullptr, &inconclusive);
return (isChanged || inconclusive);
}
static void valueFlowContainerReverse(Token *tok, nonneg int containerId, const ValueFlow::Value &value, const Settings *settings)
{
while (nullptr != (tok = tok->previous())) {
if (Token::Match(tok, "[{}]"))
break;
if (Token::Match(tok, "return|break|continue"))
break;
if (tok->varId() != containerId)
continue;
if (Token::Match(tok, "%name% ="))
break;
if (isContainerSizeChangedByFunction(tok))
break;
if (!tok->valueType() || !tok->valueType()->container)
break;
if (Token::Match(tok, "%name% . %name% (") && tok->valueType()->container->getAction(tok->strAt(2)) != Library::Container::Action::NO_ACTION)
break;
if (!hasContainerSizeGuard(tok, containerId))
setTokenValue(tok, value, settings);
}
}
struct ContainerVariableForwardAnalyzer : VariableForwardAnalyzer {
ContainerVariableForwardAnalyzer()
: VariableForwardAnalyzer()
{}
ContainerVariableForwardAnalyzer(const Variable* v, const ValueFlow::Value& val, std::vector<const Variable*> paliases, const TokenList* t)
: VariableForwardAnalyzer(v, val, std::move(paliases), t) {}
virtual bool match(const Token* tok) const OVERRIDE {
return tok->varId() == var->declarationId() || (astIsIterator(tok) && isAliasOf(tok, var->declarationId()));
}
virtual Action isWritable(const Token* tok) const OVERRIDE {
if (astIsIterator(tok))
return Action::None;
const ValueFlow::Value* value = getValue(tok);
if (!value)
return Action::None;
if (!tok->valueType() || !tok->valueType()->container)
return Action::None;
const Token* parent = tok->astParent();
if (tok->valueType()->container->stdStringLike && Token::simpleMatch(parent, "+=") && astIsLHS(tok) && parent->astOperand2()) {
const Token* rhs = parent->astOperand2();
if (rhs->tokType() == Token::eString)
return Action::Read | Action::Write;
if (rhs->valueType() && rhs->valueType()->container && rhs->valueType()->container->stdStringLike) {
if (std::any_of(rhs->values().begin(), rhs->values().end(), [&](const ValueFlow::Value &rhsval) {
return rhsval.isKnown() && rhsval.isContainerSizeValue();
}))
return Action::Read | Action::Write;
}
} else if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2));
if (action == Library::Container::Action::PUSH || action == Library::Container::Action::POP)
return Action::Read | Action::Write;
}
return Action::None;
}
virtual void writeValue(ValueFlow::Value* value, const Token* tok) const OVERRIDE {
if (!value)
return;
if (!tok->astParent())
return;
const Token* parent = tok->astParent();
if (!tok->valueType() || !tok->valueType()->container)
return;
if (tok->valueType()->container->stdStringLike && Token::simpleMatch(parent, "+=") && parent->astOperand2()) {
const Token* rhs = parent->astOperand2();
if (rhs->tokType() == Token::eString)
value->intvalue += Token::getStrLength(rhs);
else if (rhs->valueType() && rhs->valueType()->container && rhs->valueType()->container->stdStringLike) {
for (const ValueFlow::Value &rhsval : rhs->values()) {
if (rhsval.isKnown() && rhsval.isContainerSizeValue()) {
value->intvalue += rhsval.intvalue;
}
}
}
} else if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2));
if (action == Library::Container::Action::PUSH)
value->intvalue++;
if (action == Library::Container::Action::POP)
value->intvalue--;
}
}
virtual Action isModified(const Token* tok) const OVERRIDE {
Action read = Action::Read;
// An iterator wont change the container size
if (astIsIterator(tok))
return read;
if (Token::Match(tok->astParent(), "%assign%") && astIsLHS(tok))
return Action::Invalid;
if (isLikelyStreamRead(isCPP(), tok->astParent()))
return Action::Invalid;
if (isContainerSizeChanged(tok))
return Action::Invalid;
return read;
}
};
static void valueFlowContainerForward(Token *tok, const Token* endToken, const Variable* var, ValueFlow::Value value, TokenList *tokenlist)
{
ContainerVariableForwardAnalyzer a(var, value, getAliasesFromValues({value}), tokenlist);
valueFlowGenericForward(tok, endToken, a, tokenlist->getSettings());
}
static void valueFlowContainerForward(Token *tok, const Variable* var, ValueFlow::Value value, TokenList *tokenlist)
{
const Token * endOfVarScope = nullptr;
if (var->isLocal() || var->isArgument())
endOfVarScope = var->scope()->bodyEnd;
if (!endOfVarScope)
endOfVarScope = tok->scope()->bodyEnd;
valueFlowContainerForward(tok, endOfVarScope, var, std::move(value), tokenlist);
}
static bool isContainerSizeChanged(const Token *tok, int depth)
{
if (!tok)
return false;
if (!tok->valueType() || !tok->valueType()->container)
return true;
if (Token::Match(tok, "%name% %assign%|<<"))
return true;
if (Token::Match(tok, "%var% [") && tok->valueType()->container->stdAssociativeLike)
return true;
if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2));
Library::Container::Yield yield = tok->valueType()->container->getYield(tok->strAt(2));
switch (action) {
case Library::Container::Action::RESIZE:
case Library::Container::Action::CLEAR:
case Library::Container::Action::PUSH:
case Library::Container::Action::POP:
case Library::Container::Action::CHANGE:
case Library::Container::Action::INSERT:
case Library::Container::Action::ERASE:
case Library::Container::Action::CHANGE_INTERNAL:
return true;
case Library::Container::Action::NO_ACTION: // might be unknown action
return yield == Library::Container::Yield::NO_YIELD;
case Library::Container::Action::FIND:
case Library::Container::Action::CHANGE_CONTENT:
break;
}
}
if (isContainerSizeChangedByFunction(tok, depth))
return true;
return false;
}
static bool isContainerSizeChanged(nonneg int varId, const Token *start, const Token *end, int depth)
{
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() != varId)
continue;
if (isContainerSizeChanged(tok, depth))
return true;
}
return false;
}
static void valueFlowSmartPointer(TokenList *tokenlist, ErrorLogger * errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->scope())
continue;
if (!tok->scope()->isExecutable())
continue;
if (!tok->variable())
continue;
const Variable * var = tok->variable();
if (!var->isSmartPointer())
continue;
if (var->nameToken() == tok) {
if (Token::Match(tok, "%var% (|{") && tok->next()->astOperand2() && tok->next()->astOperand2()->str() != ",") {
Token * inTok = tok->next()->astOperand2();
std::list<ValueFlow::Value> values = inTok->values();
const bool constValue = inTok->isNumber();
valueFlowForwardAssign(inTok, var, values, constValue, true, tokenlist, errorLogger, settings);
} else if (Token::Match(tok, "%var% ;")) {
std::list<ValueFlow::Value> values;
ValueFlow::Value v(0);
v.setKnown();
values.push_back(v);
valueFlowForwardAssign(tok, var, values, false, true, tokenlist, errorLogger, settings);
}
} else if (Token::Match(tok, "%var% . reset (") && tok->next()->originalName() != "->") {
if (Token::simpleMatch(tok->tokAt(3), "( )")) {
std::list<ValueFlow::Value> values;
ValueFlow::Value v(0);
v.setKnown();
values.push_back(v);
valueFlowForwardAssign(tok->tokAt(4), var, values, false, false, tokenlist, errorLogger, settings);
} else {
tok->removeValues(std::mem_fn(&ValueFlow::Value::isIntValue));
Token * inTok = tok->tokAt(3)->astOperand2();
if (!inTok)
continue;
std::list<ValueFlow::Value> values = inTok->values();
const bool constValue = inTok->isNumber();
valueFlowForwardAssign(inTok, var, values, constValue, false, tokenlist, errorLogger, settings);
}
} else if (Token::Match(tok, "%var% . release ( )") && tok->next()->originalName() != "->") {
std::list<ValueFlow::Value> values;
ValueFlow::Value v(0);
v.setKnown();
values.push_back(v);
valueFlowForwardAssign(tok->tokAt(4), var, values, false, false, tokenlist, errorLogger, settings);
}
}
}
static void valueFlowIterators(TokenList *tokenlist, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->scope())
continue;
if (!tok->scope()->isExecutable())
continue;
if (!astIsContainer(tok))
continue;
if (Token::Match(tok->astParent(), ". %name% (")) {
Library::Container::Yield yield = tok->valueType()->container->getYield(tok->astParent()->strAt(1));
ValueFlow::Value v(0);
v.setKnown();
if (yield == Library::Container::Yield::START_ITERATOR) {
v.valueType = ValueFlow::Value::ITERATOR_START;
setTokenValue(tok->astParent()->tokAt(2), v, settings);
} else if (yield == Library::Container::Yield::END_ITERATOR) {
v.valueType = ValueFlow::Value::ITERATOR_END;
setTokenValue(tok->astParent()->tokAt(2), v, settings);
}
}
}
}
static std::list<ValueFlow::Value> getIteratorValues(std::list<ValueFlow::Value> values, ValueFlow::Value::ValueKind* kind = nullptr)
{
values.remove_if([&](const ValueFlow::Value& v) {
if (kind && v.valueKind != *kind)
return true;
return !v.isIteratorValue();
});
return values;
}
static void valueFlowIteratorAfterCondition(TokenList *tokenlist,
SymbolDatabase *symboldatabase,
ErrorLogger *errorLogger,
const Settings *settings)
{
ValueFlowConditionHandler handler;
handler.forward = [&](Token* start,
const Token* stop,
const Token* vartok,
const std::list<ValueFlow::Value>& values,
bool) {
valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings);
std::vector<const Variable*> vars = getExprVariables(vartok, tokenlist, symboldatabase, settings);
return isVariablesChanged(start, stop, 0, vars, settings, tokenlist->isCPP());
};
handler.parse = [&](const Token *tok) {
ValueFlowConditionHandler::Condition cond;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
if (Token::Match(tok, "==|!=")) {
if (!tok->astOperand1() || !tok->astOperand2())
return cond;
ValueFlow::Value::ValueKind kind = ValueFlow::Value::ValueKind::Known;
std::list<ValueFlow::Value> values = getIteratorValues(tok->astOperand1()->values(), &kind);
if (!values.empty()) {
cond.vartok = tok->astOperand2();
} else {
values = getIteratorValues(tok->astOperand2()->values());
if (!values.empty())
cond.vartok = tok->astOperand1();
}
for (ValueFlow::Value& v:values) {
v.setPossible();
v.assumeCondition(tok);
}
cond.true_values = values;
cond.false_values = values;
}
return cond;
};
handler.afterCondition(tokenlist, symboldatabase, errorLogger, settings);
}
static void valueFlowIteratorInfer(TokenList *tokenlist, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->scope())
continue;
if (!tok->scope()->isExecutable())
continue;
std::list<ValueFlow::Value> values = getIteratorValues(tok->values());
values.remove_if([&](const ValueFlow::Value& v) {
if (!v.isImpossible())
return true;
if (v.isIteratorEndValue() && v.intvalue <= 0)
return true;
if (v.isIteratorStartValue() && v.intvalue >= 0)
return true;
return false;
});
for (ValueFlow::Value& v:values) {
v.setPossible();
if (v.isIteratorStartValue())
v.intvalue++;
if (v.isIteratorEndValue())
v.intvalue--;
setTokenValue(tok, v, settings);
}
}
}
static void valueFlowContainerSize(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger * /*errorLogger*/, const Settings *settings)
{
// declaration
for (const Variable *var : symboldatabase->variableList()) {
if (!var || !var->isLocal() || var->isPointer() || var->isReference() || var->isStatic())
continue;
if (!var->valueType() || !var->valueType()->container)
continue;
if (!Token::Match(var->nameToken(), "%name% ;"))
continue;
if (!astIsContainer(var->nameToken()))
continue;
if (var->nameToken()->hasKnownValue())
continue;
ValueFlow::Value value(0);
if (var->valueType()->container->size_templateArgNo >= 0) {
if (var->dimensions().size() == 1 && var->dimensions().front().known)
value.intvalue = var->dimensions().front().num;
else
continue;
}
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowContainerForward(var->nameToken()->next(), var, value, tokenlist);
}
// after assignment
for (const Scope *functionScope : symboldatabase->functionScopes) {
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "%name%|;|{|} %var% = %str% ;")) {
const Token *containerTok = tok->next();
if (containerTok && containerTok->valueType() && containerTok->valueType()->container && containerTok->valueType()->container->stdStringLike) {
ValueFlow::Value value(Token::getStrLength(containerTok->tokAt(2)));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowContainerForward(containerTok->next(), containerTok->variable(), value, tokenlist);
}
} else if (Token::Match(tok, "%var% . %name% (") && tok->valueType() && tok->valueType()->container) {
Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2));
if (action == Library::Container::Action::CLEAR) {
ValueFlow::Value value(0);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowContainerForward(tok->next(), tok->variable(), value, tokenlist);
} else if (action == Library::Container::Action::RESIZE && tok->tokAt(4)->hasKnownIntValue()) {
ValueFlow::Value value(tok->tokAt(4)->values().front());
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowContainerForward(tok->next(), tok->variable(), value, tokenlist);
}
}
}
}
// conditional conditionSize
for (const Scope &scope : symboldatabase->scopeList) {
if (scope.type != Scope::ScopeType::eIf) // TODO: while
continue;
for (const Token *tok = scope.classDef; tok && tok->str() != "{"; tok = tok->next()) {
if (!tok->isName() || !tok->valueType() || tok->valueType()->type != ValueType::CONTAINER || !tok->valueType()->container)
continue;
const Token *conditionToken;
MathLib::bigint intval;
if (Token::Match(tok, "%name% . %name% (")) {
if (tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::SIZE) {
const Token *parent = tok->tokAt(3)->astParent();
if (!parent || !parent->isComparisonOp() || !parent->astOperand2())
continue;
if (parent->astOperand1()->hasKnownIntValue())
intval = parent->astOperand1()->values().front().intvalue;
else if (parent->astOperand2()->hasKnownIntValue())
intval = parent->astOperand2()->values().front().intvalue;
else
continue;
conditionToken = parent;
} else if (tok->valueType()->container->getYield(tok->strAt(2)) == Library::Container::Yield::EMPTY) {
conditionToken = tok->tokAt(3);
intval = 0;
} else {
continue;
}
} else if (tok->valueType()->container->stdStringLike && Token::Match(tok, "%name% ==|!= %str%") && tok->next()->astOperand2() == tok->tokAt(2)) {
intval = Token::getStrLength(tok->tokAt(2));
conditionToken = tok->next();
} else {
continue;
}
ValueFlow::Value value(conditionToken, intval);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
// possible value before condition
valueFlowContainerReverse(const_cast<Token *>(scope.classDef), tok->varId(), value, settings);
}
}
}
static void valueFlowContainerAfterCondition(TokenList *tokenlist,
SymbolDatabase *symboldatabase,
ErrorLogger *errorLogger,
const Settings *settings)
{
ValueFlowConditionHandler handler;
handler.forward =
[&](Token* start, const Token* stop, const Token* vartok, const std::list<ValueFlow::Value>& values, bool) {
// TODO: Forward multiple values
if (values.empty())
return false;
const Variable* var = vartok->variable();
if (!var)
return false;
valueFlowContainerForward(start->next(), stop, var, values.front(), tokenlist);
return isContainerSizeChanged(var->declarationId(), start, stop);
};
handler.parse = [&](const Token *tok) {
ValueFlowConditionHandler::Condition cond;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
const Token *vartok = parseCompareInt(tok, true_value, false_value);
if (vartok) {
vartok = vartok->tokAt(-3);
if (!isContainerSize(vartok))
return cond;
true_value.valueType = ValueFlow::Value::CONTAINER_SIZE;
false_value.valueType = ValueFlow::Value::CONTAINER_SIZE;
cond.true_values.push_back(true_value);
cond.false_values.push_back(false_value);
cond.vartok = vartok;
return cond;
}
// Empty check
if (tok->str() == "(") {
vartok = tok->tokAt(-3);
// TODO: Handle .size()
if (!isContainerEmpty(vartok))
return cond;
const Token *parent = tok->astParent();
while (parent) {
if (Token::Match(parent, "%comp%"))
return cond;
parent = parent->astParent();
}
ValueFlow::Value value(tok, 0LL);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
cond.true_values.emplace_back(value);
cond.false_values.emplace_back(std::move(value));
cond.vartok = vartok;
cond.inverted = true;
return cond;
}
// String compare
if (Token::Match(tok, "==|!=")) {
const Token *strtok = nullptr;
if (Token::Match(tok->astOperand1(), "%str%")) {
strtok = tok->astOperand1();
vartok = tok->astOperand2();
} else if (Token::Match(tok->astOperand2(), "%str%")) {
strtok = tok->astOperand2();
vartok = tok->astOperand1();
}
if (!strtok)
return cond;
if (!astIsContainer(vartok))
return cond;
ValueFlow::Value value(tok, Token::getStrLength(strtok));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
cond.false_values.emplace_back(value);
cond.true_values.emplace_back(std::move(value));
cond.vartok = vartok;
return cond;
}
return cond;
};
handler.afterCondition(tokenlist, symboldatabase, errorLogger, settings);
}
static void valueFlowFwdAnalysis(const TokenList *tokenlist, const Settings *settings)
{
for (const Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (Token::simpleMatch(tok, "for ("))
tok = tok->linkAt(1);
if (tok->str() != "=" || !tok->astOperand1() || !tok->astOperand2())
continue;
// Skip variables
if (tok->astOperand1()->variable())
continue;
if (!tok->scope()->isExecutable())
continue;
if (!tok->astOperand2()->hasKnownIntValue())
continue;
ValueFlow::Value v(tok->astOperand2()->values().front());
v.errorPath.emplace_back(tok, tok->astOperand1()->expressionString() + " is assigned value " + MathLib::toString(v.intvalue));
const Token *startToken = tok->findExpressionStartEndTokens().second->next();
const Scope *functionScope = tok->scope();
while (functionScope->nestedIn && functionScope->nestedIn->isExecutable())
functionScope = functionScope->nestedIn;
const Token *endToken = functionScope->bodyEnd;
valueFlowForwardExpression(const_cast<Token*>(startToken), endToken, tok->astOperand1(), {v}, tokenlist, settings);
}
}
static void valueFlowDynamicBufferSize(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope *functionScope : symboldatabase->functionScopes) {
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "[;{}] %var% ="))
continue;
if (!tok->next()->variable())
continue;
const Token *rhs = tok->tokAt(2)->astOperand2();
while (rhs && rhs->isCast())
rhs = rhs->astOperand2() ? rhs->astOperand2() : rhs->astOperand1();
if (!rhs)
continue;
if (!Token::Match(rhs->previous(), "%name% ("))
continue;
const Library::AllocFunc *allocFunc = settings->library.getAllocFuncInfo(rhs->previous());
if (!allocFunc)
allocFunc = settings->library.getReallocFuncInfo(rhs->previous());
if (!allocFunc || allocFunc->bufferSize == Library::AllocFunc::BufferSize::none)
continue;
const std::vector<const Token *> args = getArguments(rhs->previous());
const Token * const arg1 = (args.size() >= allocFunc->bufferSizeArg1) ? args[allocFunc->bufferSizeArg1 - 1] : nullptr;
const Token * const arg2 = (args.size() >= allocFunc->bufferSizeArg2) ? args[allocFunc->bufferSizeArg2 - 1] : nullptr;
MathLib::bigint sizeValue = -1;
switch (allocFunc->bufferSize) {
case Library::AllocFunc::BufferSize::none:
break;
case Library::AllocFunc::BufferSize::malloc:
if (arg1 && arg1->hasKnownIntValue())
sizeValue = arg1->getKnownIntValue();
break;
case Library::AllocFunc::BufferSize::calloc:
if (arg1 && arg2 && arg1->hasKnownIntValue() && arg2->hasKnownIntValue())
sizeValue = arg1->getKnownIntValue() * arg2->getKnownIntValue();
break;
case Library::AllocFunc::BufferSize::strdup:
if (arg1 && arg1->hasKnownValue()) {
const ValueFlow::Value &value = arg1->values().back();
if (value.isTokValue() && value.tokvalue->tokType() == Token::eString)
sizeValue = Token::getStrLength(value.tokvalue) + 1; // Add one for the null terminator
}
break;
}
if (sizeValue < 0)
continue;
ValueFlow::Value value(sizeValue);
value.errorPath.emplace_back(tok->tokAt(2), "Assign " + tok->strAt(1) + ", buffer with size " + MathLib::toString(sizeValue));
value.valueType = ValueFlow::Value::ValueType::BUFFER_SIZE;
value.setKnown();
const std::list<ValueFlow::Value> values{value};
valueFlowForwardVariable(const_cast<Token*>(rhs),
functionScope->bodyEnd,
tok->next()->variable(),
tok->next()->varId(),
values,
true,
false,
tokenlist,
errorLogger,
settings);
}
}
}
static bool getMinMaxValues(const ValueType *vt, const cppcheck::Platform &platform, MathLib::bigint *minValue, MathLib::bigint *maxValue)
{
if (!vt || !vt->isIntegral() || vt->pointer)
return false;
int bits;
switch (vt->type) {
case ValueType::Type::BOOL:
bits = 1;
break;
case ValueType::Type::CHAR:
bits = platform.char_bit;
break;
case ValueType::Type::SHORT:
bits = platform.short_bit;
break;
case ValueType::Type::INT:
bits = platform.int_bit;
break;
case ValueType::Type::LONG:
bits = platform.long_bit;
break;
case ValueType::Type::LONGLONG:
bits = platform.long_long_bit;
break;
default:
return false;
}
if (bits == 1) {
*minValue = 0;
*maxValue = 1;
} else if (bits < 62) {
if (vt->sign == ValueType::Sign::UNSIGNED) {
*minValue = 0;
*maxValue = (1LL << bits) - 1;
} else {
*minValue = -(1LL << (bits - 1));
*maxValue = (1LL << (bits - 1)) - 1;
}
} else if (bits == 64) {
if (vt->sign == ValueType::Sign::UNSIGNED) {
*minValue = 0;
*maxValue = LLONG_MAX; // todo max unsigned value
} else {
*minValue = LLONG_MIN;
*maxValue = LLONG_MAX;
}
} else {
return false;
}
return true;
}
static bool getMinMaxValues(const std::string &typestr, const Settings *settings, MathLib::bigint *minvalue, MathLib::bigint *maxvalue)
{
TokenList typeTokens(settings);
std::istringstream istr(typestr+";");
if (!typeTokens.createTokens(istr))
return false;
typeTokens.simplifyPlatformTypes();
typeTokens.simplifyStdType();
const ValueType &vt = ValueType::parseDecl(typeTokens.front(), settings);
return getMinMaxValues(&vt, *settings, minvalue, maxvalue);
}
static void valueFlowSafeFunctions(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope *functionScope : symboldatabase->functionScopes) {
if (!functionScope->bodyStart)
continue;
const Function *function = functionScope->function;
if (!function)
continue;
const bool safe = function->isSafe(settings);
const bool all = safe && settings->platformType != cppcheck::Platform::PlatformType::Unspecified;
for (const Variable &arg : function->argumentList) {
if (!arg.nameToken() || !arg.valueType())
continue;
if (arg.valueType()->type == ValueType::Type::CONTAINER) {
if (!safe)
continue;
std::list<ValueFlow::Value> argValues;
argValues.emplace_back(0);
argValues.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Assuming " + arg.name() + " is empty");
argValues.back().safe = true;
argValues.emplace_back(1000000);
argValues.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Assuming " + arg.name() + " size is 1000000");
argValues.back().safe = true;
for (const ValueFlow::Value &value : argValues)
valueFlowContainerForward(const_cast<Token*>(functionScope->bodyStart), &arg, value, tokenlist);
continue;
}
MathLib::bigint low, high;
bool isLow = arg.nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::LOW, &low);
bool isHigh = arg.nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::HIGH, &high);
if (!isLow && !isHigh && !all)
continue;
const bool safeLow = !isLow;
const bool safeHigh = !isHigh;
if ((!isLow || !isHigh) && all) {
MathLib::bigint minValue, maxValue;
if (getMinMaxValues(arg.valueType(), *settings, &minValue, &maxValue)) {
if (!isLow)
low = minValue;
if (!isHigh)
high = maxValue;
isLow = isHigh = true;
} else if (arg.valueType()->type == ValueType::Type::FLOAT || arg.valueType()->type == ValueType::Type::DOUBLE || arg.valueType()->type == ValueType::Type::LONGDOUBLE) {
std::list<ValueFlow::Value> argValues;
argValues.emplace_back(0);
argValues.back().valueType = ValueFlow::Value::ValueType::FLOAT;
argValues.back().floatValue = isLow ? low : -1E25f;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue));
argValues.back().safe = true;
argValues.emplace_back(0);
argValues.back().valueType = ValueFlow::Value::ValueType::FLOAT;
argValues.back().floatValue = isHigh ? high : 1E25f;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue));
argValues.back().safe = true;
valueFlowForwardVariable(const_cast<Token*>(functionScope->bodyStart->next()),
functionScope->bodyEnd,
&arg,
arg.declarationId(),
argValues,
false,
false,
tokenlist,
errorLogger,
settings);
continue;
}
}
std::list<ValueFlow::Value> argValues;
if (isLow) {
argValues.emplace_back(low);
argValues.back().errorPath.emplace_back(arg.nameToken(), std::string(safeLow ? "Safe checks: " : "") + "Assuming argument has value " + MathLib::toString(low));
argValues.back().safe = safeLow;
}
if (isHigh) {
argValues.emplace_back(high);
argValues.back().errorPath.emplace_back(arg.nameToken(), std::string(safeHigh ? "Safe checks: " : "") + "Assuming argument has value " + MathLib::toString(high));
argValues.back().safe = safeHigh;
}
if (!argValues.empty())
valueFlowForwardVariable(const_cast<Token*>(functionScope->bodyStart->next()),
functionScope->bodyEnd,
&arg,
arg.declarationId(),
argValues,
false,
false,
tokenlist,
errorLogger,
settings);
}
}
}
static void valueFlowUnknownFunctionReturn(TokenList *tokenlist, const Settings *settings)
{
if (settings->checkUnknownFunctionReturn.empty())
return;
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->astParent() || tok->str() != "(" || !tok->previous()->isName())
continue;
if (settings->checkUnknownFunctionReturn.find(tok->previous()->str()) == settings->checkUnknownFunctionReturn.end())
continue;
std::vector<MathLib::bigint> unknownValues = settings->library.unknownReturnValues(tok->astOperand1());
if (unknownValues.empty())
continue;
// Get min/max values for return type
const std::string &typestr = settings->library.returnValueType(tok->previous());
MathLib::bigint minvalue, maxvalue;
if (!getMinMaxValues(typestr, settings, &minvalue, &maxvalue))
continue;
for (MathLib::bigint value : unknownValues) {
if (value < minvalue)
value = minvalue;
else if (value > maxvalue)
value = maxvalue;
setTokenValue(const_cast<Token *>(tok), ValueFlow::Value(value), settings);
}
}
}
ValueFlow::Value::Value(const Token* c, long long val)
: valueType(INT),
bound(Bound::Point),
intvalue(val),
tokvalue(nullptr),
floatValue(0.0),
moveKind(MoveKind::NonMovedVariable),
varvalue(val),
condition(c),
varId(0U),
safe(false),
conditional(false),
defaultArg(false),
indirect(0),
path(0),
lifetimeKind(LifetimeKind::Object),
lifetimeScope(LifetimeScope::Local),
valueKind(ValueKind::Possible)
{
errorPath.emplace_back(c, "Assuming that condition '" + c->expressionString() + "' is not redundant");
}
void ValueFlow::Value::assumeCondition(const Token* tok)
{
condition = tok;
errorPath.emplace_back(tok, "Assuming that condition '" + tok->expressionString() + "' is not redundant");
}
std::string ValueFlow::Value::infoString() const
{
switch (valueType) {
case INT:
return MathLib::toString(intvalue);
case TOK:
return tokvalue->str();
case FLOAT:
return MathLib::toString(floatValue);
case MOVED:
return "<Moved>";
case UNINIT:
return "<Uninit>";
case BUFFER_SIZE:
case CONTAINER_SIZE:
return "size=" + MathLib::toString(intvalue);
case ITERATOR_START:
return "start=" + MathLib::toString(intvalue);
case ITERATOR_END:
return "end=" + MathLib::toString(intvalue);
case LIFETIME:
return "lifetime=" + tokvalue->str();
}
throw InternalError(nullptr, "Invalid ValueFlow Value type");
}
const char* ValueFlow::Value::toString(MoveKind moveKind)
{
switch (moveKind) {
case MoveKind::NonMovedVariable:
return "NonMovedVariable";
case MoveKind::MovedVariable:
return "MovedVariable";
case MoveKind::ForwardedVariable:
return "ForwardedVariable";
}
return "";
}
const ValueFlow::Value *ValueFlow::valueFlowConstantFoldAST(Token *expr, const Settings *settings)
{
if (expr && expr->values().empty()) {
valueFlowConstantFoldAST(expr->astOperand1(), settings);
valueFlowConstantFoldAST(expr->astOperand2(), settings);
valueFlowSetConstantValue(expr, settings, true /* TODO: this is a guess */);
}
return expr && expr->hasKnownValue() ? &expr->values().front() : nullptr;
}
static std::size_t getTotalValues(TokenList *tokenlist)
{
std::size_t n = 1;
for (Token *tok = tokenlist->front(); tok; tok = tok->next())
n += tok->values().size();
return n;
}
void ValueFlow::setValues(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next())
tok->clearValueFlow();
valueFlowNumber(tokenlist);
valueFlowString(tokenlist);
valueFlowArray(tokenlist);
valueFlowUnknownFunctionReturn(tokenlist, settings);
valueFlowGlobalConstVar(tokenlist, settings);
valueFlowGlobalStaticVar(tokenlist, settings);
valueFlowPointerAlias(tokenlist);
valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings);
valueFlowFunctionReturn(tokenlist, errorLogger);
valueFlowBitAnd(tokenlist);
valueFlowSameExpressions(tokenlist);
valueFlowFwdAnalysis(tokenlist, settings);
std::size_t values = 0;
std::size_t n = 4;
while (n > 0 && values < getTotalValues(tokenlist)) {
values = getTotalValues(tokenlist);
valueFlowPointerAliasDeref(tokenlist);
valueFlowArrayBool(tokenlist);
valueFlowRightShift(tokenlist, settings);
valueFlowOppositeCondition(symboldatabase, settings);
valueFlowTerminatingCondition(tokenlist, symboldatabase, errorLogger, settings);
valueFlowBeforeCondition(tokenlist, symboldatabase, errorLogger, settings);
valueFlowAfterMove(tokenlist, symboldatabase, errorLogger, settings);
valueFlowAfterCondition(tokenlist, symboldatabase, errorLogger, settings);
valueFlowInferCondition(tokenlist, settings);
valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, settings);
valueFlowSwitchVariable(tokenlist, symboldatabase, errorLogger, settings);
valueFlowForLoop(tokenlist, symboldatabase, errorLogger, settings);
valueFlowSubFunction(tokenlist, symboldatabase, errorLogger, settings);
valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings);
valueFlowFunctionDefaultParameter(tokenlist, symboldatabase, errorLogger, settings);
valueFlowUninit(tokenlist, symboldatabase, errorLogger, settings);
if (tokenlist->isCPP()) {
valueFlowSmartPointer(tokenlist, errorLogger, settings);
valueFlowIterators(tokenlist, settings);
valueFlowIteratorAfterCondition(tokenlist, symboldatabase, errorLogger, settings);
valueFlowIteratorInfer(tokenlist, settings);
valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings);
valueFlowContainerAfterCondition(tokenlist, symboldatabase, errorLogger, settings);
}
valueFlowSafeFunctions(tokenlist, symboldatabase, errorLogger, settings);
n--;
}
valueFlowDynamicBufferSize(tokenlist, symboldatabase, errorLogger, settings);
}
std::string ValueFlow::eitherTheConditionIsRedundant(const Token *condition)
{
if (!condition)
return "Either the condition is redundant";
if (condition->str() == "case") {
std::string expr;
for (const Token *tok = condition; tok && tok->str() != ":"; tok = tok->next()) {
expr += tok->str();
if (Token::Match(tok, "%name%|%num% %name%|%num%"))
expr += ' ';
}
return "Either the switch case '" + expr + "' is redundant";
}
return "Either the condition '" + condition->expressionString() + "' is redundant";
}
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