403 lines
14 KiB
C++
403 lines
14 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2021 Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "infer.h"
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#include "calculate.h"
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#include "errortypes.h"
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#include "valueptr.h"
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#include <cassert>
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#include <algorithm>
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#include <functional>
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#include <iterator>
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#include <unordered_set>
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#include <utility>
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class Token;
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template<class Predicate, class Compare>
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static const ValueFlow::Value* getCompareValue(const std::list<ValueFlow::Value>& values, Predicate pred, Compare compare)
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{
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const ValueFlow::Value* result = nullptr;
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for (const ValueFlow::Value& value : values) {
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if (!pred(value))
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continue;
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if (result)
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result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) {
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return compare(x.intvalue, y.intvalue);
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});
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else
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result = &value;
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}
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return result;
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}
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struct Interval {
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std::vector<MathLib::bigint> minvalue = {};
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std::vector<MathLib::bigint> maxvalue = {};
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std::vector<const ValueFlow::Value*> minRef = {};
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std::vector<const ValueFlow::Value*> maxRef = {};
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std::string str() const
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{
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std::string result = "[";
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if (minvalue.size() == 1)
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result += std::to_string(minvalue.front());
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else
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result += "*";
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result += ",";
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if (maxvalue.size() == 1)
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result += std::to_string(maxvalue.front());
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else
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result += "*";
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result += "]";
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return result;
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}
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void setMinValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
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{
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minvalue = {x};
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if (ref)
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minRef = {ref};
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}
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void setMaxValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
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{
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maxvalue = {x};
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if (ref)
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maxRef = {ref};
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}
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bool isLessThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
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{
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if (!this->maxvalue.empty() && this->maxvalue.front() < x) {
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if (ref)
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*ref = maxRef;
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return true;
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}
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return false;
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}
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bool isGreaterThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
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{
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if (!this->minvalue.empty() && this->minvalue.front() > x) {
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if (ref)
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*ref = minRef;
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return true;
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}
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return false;
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}
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bool isScalar() const {
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return minvalue.size() == 1 && minvalue == maxvalue;
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}
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bool empty() const {
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return minvalue.empty() && maxvalue.empty();
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}
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bool isScalarOrEmpty() const {
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return empty() || isScalar();
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}
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MathLib::bigint getScalar() const
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{
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assert(isScalar());
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return minvalue.front();
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}
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std::vector<const ValueFlow::Value*> getScalarRef() const
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{
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assert(isScalar());
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if (minRef != maxRef)
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return merge(minRef, maxRef);
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return minRef;
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}
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static Interval fromInt(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
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{
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Interval result;
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result.setMinValue(x, ref);
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result.setMaxValue(x, ref);
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return result;
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}
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template<class Predicate>
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static Interval fromValues(const std::list<ValueFlow::Value>& values, Predicate predicate)
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{
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Interval result;
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const ValueFlow::Value* minValue = getCompareValue(values, predicate, std::less<MathLib::bigint>{});
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if (minValue) {
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if (minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper)
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result.setMinValue(minValue->intvalue + 1, minValue);
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if (minValue->isPossible() && minValue->bound == ValueFlow::Value::Bound::Lower)
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result.setMinValue(minValue->intvalue, minValue);
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if (minValue->isKnown())
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return Interval::fromInt(minValue->intvalue, minValue);
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}
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const ValueFlow::Value* maxValue = getCompareValue(values, predicate, std::greater<MathLib::bigint>{});
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if (maxValue) {
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if (maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower)
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result.setMaxValue(maxValue->intvalue - 1, maxValue);
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if (maxValue->isPossible() && maxValue->bound == ValueFlow::Value::Bound::Upper)
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result.setMaxValue(maxValue->intvalue, maxValue);
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assert(!maxValue->isKnown());
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}
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return result;
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}
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static Interval fromValues(const std::list<ValueFlow::Value>& values)
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{
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return Interval::fromValues(values, [](const ValueFlow::Value&) {
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return true;
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});
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}
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template<class F>
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static std::vector<MathLib::bigint> apply(const std::vector<MathLib::bigint>& x,
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const std::vector<MathLib::bigint>& y,
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F f)
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{
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if (x.empty())
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return {};
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if (y.empty())
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return {};
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return {f(x.front(), y.front())};
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}
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static std::vector<const ValueFlow::Value*> merge(std::vector<const ValueFlow::Value*> x,
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const std::vector<const ValueFlow::Value*>& y)
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{
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x.insert(x.end(), y.begin(), y.end());
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return x;
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}
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friend Interval operator-(const Interval& lhs, const Interval& rhs)
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{
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Interval result;
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result.minvalue = Interval::apply(lhs.minvalue, rhs.maxvalue, std::minus<MathLib::bigint>{});
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result.maxvalue = Interval::apply(lhs.maxvalue, rhs.minvalue, std::minus<MathLib::bigint>{});
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if (!result.minvalue.empty())
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result.minRef = merge(lhs.minRef, rhs.maxRef);
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if (!result.maxvalue.empty())
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result.maxRef = merge(lhs.maxRef, rhs.minRef);
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return result;
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}
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static std::vector<int> equal(const Interval& lhs,
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const Interval& rhs,
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std::vector<const ValueFlow::Value*>* ref = nullptr)
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{
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if (!lhs.isScalar())
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return {};
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if (!rhs.isScalar())
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return {};
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if (ref)
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*ref = merge(lhs.getScalarRef(), rhs.getScalarRef());
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return {lhs.minvalue == rhs.minvalue};
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}
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static std::vector<int> compare(const Interval& lhs,
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const Interval& rhs,
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std::vector<const ValueFlow::Value*>* ref = nullptr)
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{
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Interval diff = lhs - rhs;
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if (diff.isGreaterThan(0, ref))
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return {1};
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if (diff.isLessThan(0, ref))
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return {-1};
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std::vector<int> eq = Interval::equal(lhs, rhs, ref);
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if (!eq.empty()) {
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if (eq.front() == 0)
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return {1, -1};
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else
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return {0};
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}
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if (diff.isGreaterThan(-1, ref))
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return {0, 1};
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if (diff.isLessThan(1, ref))
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return {0, -1};
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return {};
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}
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static std::vector<bool> compare(const std::string& op,
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const Interval& lhs,
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const Interval& rhs,
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std::vector<const ValueFlow::Value*>* ref = nullptr)
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{
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std::vector<int> r = compare(lhs, rhs, ref);
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if (r.empty())
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return {};
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bool b = calculate(op, r.front(), 0);
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if (std::all_of(r.begin() + 1, r.end(), [&](int i) {
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return b == calculate(op, i, 0);
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}))
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return {b};
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return {};
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}
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};
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std::string toString(const Interval& i) {
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return i.str();
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}
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static void addToErrorPath(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
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{
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std::unordered_set<const Token*> locations;
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for (const ValueFlow::Value* ref : refs) {
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if (ref->condition && !value.condition)
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value.condition = ref->condition;
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std::copy_if(ref->errorPath.begin(),
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ref->errorPath.end(),
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std::back_inserter(value.errorPath),
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[&](const ErrorPathItem& e) {
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return locations.insert(e.first).second;
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});
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}
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}
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static void setValueKind(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
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{
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bool isPossible = false;
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bool isInconclusive = false;
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for (const ValueFlow::Value* ref : refs) {
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if (ref->isPossible())
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isPossible = true;
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if (ref->isInconclusive())
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isInconclusive = true;
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}
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if (isInconclusive)
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value.setInconclusive();
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else if (isPossible)
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value.setPossible();
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else
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value.setKnown();
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}
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static bool inferNotEqual(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
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{
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return std::any_of(values.begin(), values.end(), [&](const ValueFlow::Value& value) {
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return value.isImpossible() && value.intvalue == x;
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});
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}
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std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
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const std::string& op,
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std::list<ValueFlow::Value> lhsValues,
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std::list<ValueFlow::Value> rhsValues)
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{
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std::vector<ValueFlow::Value> result;
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auto notMatch = [&](const ValueFlow::Value& value) {
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return !model->match(value);
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};
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lhsValues.remove_if(notMatch);
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rhsValues.remove_if(notMatch);
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if (lhsValues.empty() || rhsValues.empty())
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return result;
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Interval lhs = Interval::fromValues(lhsValues);
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Interval rhs = Interval::fromValues(rhsValues);
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if (op == "-") {
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Interval diff = lhs - rhs;
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if (diff.isScalar()) {
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std::vector<const ValueFlow::Value*> refs = diff.getScalarRef();
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ValueFlow::Value value(diff.getScalar());
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addToErrorPath(value, refs);
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setValueKind(value, refs);
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result.push_back(value);
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} else {
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if (!diff.minvalue.empty()) {
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ValueFlow::Value value(diff.minvalue.front() - 1);
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value.setImpossible();
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value.bound = ValueFlow::Value::Bound::Upper;
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addToErrorPath(value, diff.minRef);
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result.push_back(value);
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}
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if (!diff.maxvalue.empty()) {
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ValueFlow::Value value(diff.maxvalue.front() + 1);
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value.setImpossible();
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value.bound = ValueFlow::Value::Bound::Lower;
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addToErrorPath(value, diff.maxRef);
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result.push_back(value);
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}
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}
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} else if ((op == "!=" || op == "==") && lhs.isScalarOrEmpty() && rhs.isScalarOrEmpty()) {
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if (lhs.isScalar() && rhs.isScalar()) {
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std::vector<const ValueFlow::Value*> refs = Interval::merge(lhs.getScalarRef(), rhs.getScalarRef());
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ValueFlow::Value value(calculate(op, lhs.getScalar(), rhs.getScalar()));
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addToErrorPath(value, refs);
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setValueKind(value, refs);
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result.push_back(value);
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} else {
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std::vector<const ValueFlow::Value*> refs;
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if (lhs.isScalar() && inferNotEqual(rhsValues, lhs.getScalar()))
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refs = lhs.getScalarRef();
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else if (rhs.isScalar() && inferNotEqual(lhsValues, rhs.getScalar()))
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refs = rhs.getScalarRef();
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if (!refs.empty()) {
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ValueFlow::Value value(op == "!=");
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addToErrorPath(value, refs);
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setValueKind(value, refs);
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result.push_back(value);
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}
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}
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} else {
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std::vector<const ValueFlow::Value*> refs;
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std::vector<bool> r = Interval::compare(op, lhs, rhs, &refs);
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if (!r.empty()) {
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ValueFlow::Value value(r.front());
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addToErrorPath(value, refs);
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setValueKind(value, refs);
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result.push_back(value);
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}
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}
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return result;
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}
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std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
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const std::string& op,
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MathLib::bigint lhs,
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std::list<ValueFlow::Value> rhsValues)
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{
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return infer(model, op, {model->yield(lhs)}, std::move(rhsValues));
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}
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std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
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const std::string& op,
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std::list<ValueFlow::Value> lhsValues,
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MathLib::bigint rhs)
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{
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return infer(model, op, std::move(lhsValues), {model->yield(rhs)});
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}
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std::vector<MathLib::bigint> getMinValue(const ValuePtr<InferModel>& model, const std::list<ValueFlow::Value>& values)
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{
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return Interval::fromValues(values, [&](const ValueFlow::Value& v) {
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return model->match(v);
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}).minvalue;
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}
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std::vector<MathLib::bigint> getMaxValue(const ValuePtr<InferModel>& model, const std::list<ValueFlow::Value>& values)
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{
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return Interval::fromValues(values, [&](const ValueFlow::Value& v) {
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return model->match(v);
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}).maxvalue;
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}
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