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390 lines (356 loc) · 14.2 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2024 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "infer.h"
#include "calculate.h"
#include "errortypes.h"
#include "valueptr.h"
#include <cassert>
#include <algorithm>
#include <functional>
#include <iterator>
#include <unordered_set>
#include <utility>
class Token;
template<class Predicate, class Compare>
static const ValueFlow::Value* getCompareValue(const std::list<ValueFlow::Value>& values, Predicate pred, Compare compare)
{
const ValueFlow::Value* result = nullptr;
for (const ValueFlow::Value& value : values) {
if (!pred(value))
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;
}
namespace {
struct Interval {
std::vector<MathLib::bigint> minvalue, maxvalue;
std::vector<const ValueFlow::Value*> minRef, maxRef;
void setMinValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
{
minvalue = {x};
if (ref)
minRef = {ref};
}
void setMaxValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
{
maxvalue = {x};
if (ref)
maxRef = {ref};
}
bool isLessThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
{
if (!this->maxvalue.empty() && this->maxvalue.front() < x) {
if (ref)
*ref = maxRef;
return true;
}
return false;
}
bool isGreaterThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
{
if (!this->minvalue.empty() && this->minvalue.front() > x) {
if (ref)
*ref = minRef;
return true;
}
return false;
}
bool isScalar() const {
return minvalue.size() == 1 && minvalue == maxvalue;
}
bool empty() const {
return minvalue.empty() && maxvalue.empty();
}
bool isScalarOrEmpty() const {
return empty() || isScalar();
}
MathLib::bigint getScalar() const
{
assert(isScalar());
return minvalue.front();
}
std::vector<const ValueFlow::Value*> getScalarRef() const
{
assert(isScalar());
if (minRef != maxRef)
return merge(minRef, maxRef);
return minRef;
}
static Interval fromInt(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
{
Interval result;
result.setMinValue(x, ref);
result.setMaxValue(x, ref);
return result;
}
template<class Predicate>
static Interval fromValues(const std::list<ValueFlow::Value>& values, Predicate predicate)
{
Interval result;
const ValueFlow::Value* minValue = getCompareValue(values, predicate, std::less<MathLib::bigint>{});
if (minValue) {
if (minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper)
result.setMinValue(minValue->intvalue + 1, minValue);
if (minValue->isPossible() && minValue->bound == ValueFlow::Value::Bound::Lower)
result.setMinValue(minValue->intvalue, minValue);
if (!minValue->isImpossible() && (minValue->bound == ValueFlow::Value::Bound::Point || minValue->isKnown()) &&
std::count_if(values.begin(), values.end(), predicate) == 1)
return Interval::fromInt(minValue->intvalue, minValue);
}
const ValueFlow::Value* maxValue = getCompareValue(values, predicate, std::greater<MathLib::bigint>{});
if (maxValue) {
if (maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower)
result.setMaxValue(maxValue->intvalue - 1, maxValue);
if (maxValue->isPossible() && maxValue->bound == ValueFlow::Value::Bound::Upper)
result.setMaxValue(maxValue->intvalue, maxValue);
assert(!maxValue->isKnown());
}
return result;
}
static Interval fromValues(const std::list<ValueFlow::Value>& values)
{
return Interval::fromValues(values, [](const ValueFlow::Value&) {
return true;
});
}
template<class F>
static std::vector<MathLib::bigint> apply(const std::vector<MathLib::bigint>& x,
const std::vector<MathLib::bigint>& y,
F f)
{
if (x.empty())
return {};
if (y.empty())
return {};
return {f(x.front(), y.front())};
}
static std::vector<const ValueFlow::Value*> merge(std::vector<const ValueFlow::Value*> x,
const std::vector<const ValueFlow::Value*>& y)
{
x.insert(x.end(), y.cbegin(), y.cend());
return x;
}
friend Interval operator-(const Interval& lhs, const Interval& rhs)
{
Interval result;
result.minvalue = Interval::apply(lhs.minvalue, rhs.maxvalue, std::minus<MathLib::bigint>{});
result.maxvalue = Interval::apply(lhs.maxvalue, rhs.minvalue, std::minus<MathLib::bigint>{});
if (!result.minvalue.empty())
result.minRef = merge(lhs.minRef, rhs.maxRef);
if (!result.maxvalue.empty())
result.maxRef = merge(lhs.maxRef, rhs.minRef);
return result;
}
static std::vector<int> equal(const Interval& lhs,
const Interval& rhs,
std::vector<const ValueFlow::Value*>* ref = nullptr)
{
if (!lhs.isScalar())
return {};
if (!rhs.isScalar())
return {};
if (ref)
*ref = merge(lhs.getScalarRef(), rhs.getScalarRef());
return {lhs.minvalue == rhs.minvalue};
}
static std::vector<int> compare(const Interval& lhs,
const Interval& rhs,
std::vector<const ValueFlow::Value*>* ref = nullptr)
{
Interval diff = lhs - rhs;
if (diff.isGreaterThan(0, ref))
return {1};
if (diff.isLessThan(0, ref))
return {-1};
std::vector<int> eq = Interval::equal(lhs, rhs, ref);
if (!eq.empty()) {
if (eq.front() == 0)
return {1, -1};
return {0};
}
if (diff.isGreaterThan(-1, ref))
return {0, 1};
if (diff.isLessThan(1, ref))
return {0, -1};
return {};
}
static std::vector<bool> compare(const std::string& op,
const Interval& lhs,
const Interval& rhs,
std::vector<const ValueFlow::Value*>* ref = nullptr)
{
std::vector<int> r = compare(lhs, rhs, ref);
if (r.empty())
return {};
bool b = calculate(op, r.front(), 0);
if (std::all_of(r.cbegin() + 1, r.cend(), [&](int i) {
return b == calculate(op, i, 0);
}))
return {b};
return {};
}
};
}
static void addToErrorPath(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
{
std::unordered_set<const Token*> locations;
for (const ValueFlow::Value* ref : refs) {
if (ref->condition && !value.condition)
value.condition = ref->condition;
std::copy_if(ref->errorPath.cbegin(),
ref->errorPath.cend(),
std::back_inserter(value.errorPath),
[&](const ErrorPathItem& e) {
return locations.insert(e.first).second;
});
std::copy_if(ref->debugPath.cbegin(),
ref->debugPath.cend(),
std::back_inserter(value.debugPath),
[&](const ErrorPathItem& e) {
return locations.insert(e.first).second;
});
}
}
static void setValueKind(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
{
bool isPossible = false;
bool isInconclusive = false;
for (const ValueFlow::Value* ref : refs) {
if (ref->isPossible())
isPossible = true;
if (ref->isInconclusive())
isInconclusive = true;
}
if (isInconclusive)
value.setInconclusive();
else if (isPossible)
value.setPossible();
else
value.setKnown();
}
static bool inferNotEqual(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
{
return std::any_of(values.cbegin(), values.cend(), [&](const ValueFlow::Value& value) {
return value.isImpossible() && value.intvalue == x;
});
}
std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
const std::string& op,
std::list<ValueFlow::Value> lhsValues,
std::list<ValueFlow::Value> rhsValues)
{
std::vector<ValueFlow::Value> result;
auto notMatch = [&](const ValueFlow::Value& value) {
return !model->match(value);
};
lhsValues.remove_if(notMatch);
if (lhsValues.empty())
return result;
rhsValues.remove_if(notMatch);
if (rhsValues.empty())
return result;
Interval lhs = Interval::fromValues(lhsValues);
Interval rhs = Interval::fromValues(rhsValues);
if (op == "-") {
Interval diff = lhs - rhs;
if (diff.isScalar()) {
std::vector<const ValueFlow::Value*> refs = diff.getScalarRef();
ValueFlow::Value value(diff.getScalar());
addToErrorPath(value, refs);
setValueKind(value, refs);
result.push_back(std::move(value));
} else {
if (!diff.minvalue.empty()) {
ValueFlow::Value value(diff.minvalue.front() - 1);
value.setImpossible();
value.bound = ValueFlow::Value::Bound::Upper;
addToErrorPath(value, diff.minRef);
result.push_back(std::move(value));
}
if (!diff.maxvalue.empty()) {
ValueFlow::Value value(diff.maxvalue.front() + 1);
value.setImpossible();
value.bound = ValueFlow::Value::Bound::Lower;
addToErrorPath(value, diff.maxRef);
result.push_back(std::move(value));
}
}
} else if ((op == "!=" || op == "==") && lhs.isScalarOrEmpty() && rhs.isScalarOrEmpty()) {
if (lhs.isScalar() && rhs.isScalar()) {
std::vector<const ValueFlow::Value*> refs = Interval::merge(lhs.getScalarRef(), rhs.getScalarRef());
ValueFlow::Value value(calculate(op, lhs.getScalar(), rhs.getScalar()));
addToErrorPath(value, refs);
setValueKind(value, refs);
result.push_back(std::move(value));
} else {
std::vector<const ValueFlow::Value*> refs;
if (lhs.isScalar() && inferNotEqual(rhsValues, lhs.getScalar()))
refs = lhs.getScalarRef();
else if (rhs.isScalar() && inferNotEqual(lhsValues, rhs.getScalar()))
refs = rhs.getScalarRef();
if (!refs.empty()) {
ValueFlow::Value value(op == "!=");
addToErrorPath(value, refs);
setValueKind(value, refs);
result.push_back(std::move(value));
}
}
} else {
std::vector<const ValueFlow::Value*> refs;
std::vector<bool> r = Interval::compare(op, lhs, rhs, &refs);
if (!r.empty()) {
ValueFlow::Value value(r.front());
addToErrorPath(value, refs);
setValueKind(value, refs);
result.push_back(std::move(value));
}
}
return result;
}
std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
const std::string& op,
MathLib::bigint lhs,
std::list<ValueFlow::Value> rhsValues)
{
return infer(model, op, {model->yield(lhs)}, std::move(rhsValues));
}
std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
const std::string& op,
std::list<ValueFlow::Value> lhsValues,
MathLib::bigint rhs)
{
return infer(model, op, std::move(lhsValues), {model->yield(rhs)});
}
std::vector<MathLib::bigint> getMinValue(const ValuePtr<InferModel>& model, const std::list<ValueFlow::Value>& values)
{
return Interval::fromValues(values, [&](const ValueFlow::Value& v) {
return model->match(v);
}).minvalue;
}
std::vector<MathLib::bigint> getMaxValue(const ValuePtr<InferModel>& model, const std::list<ValueFlow::Value>& values)
{
return Interval::fromValues(values, [&](const ValueFlow::Value& v) {
return model->match(v);
}).maxvalue;
}