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cppcheck/lib/valueflow.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2023 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 valueFlowForward 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 "analyzer.h"
#include "astutils.h"
#include "calculate.h"
#include "checkuninitvar.h"
#include "config.h"
#include "errorlogger.h"
#include "errortypes.h"
#include "findtoken.h"
#include "forwardanalyzer.h"
#include "infer.h"
#include "library.h"
#include "mathlib.h"
#include "path.h"
#include "platform.h"
#include "programmemory.h"
#include "reverseanalyzer.h"
#include "settings.h"
#include "smallvector.h"
#include "sourcelocation.h"
#include "standards.h"
#include "symboldatabase.h"
#include "timer.h"
#include "token.h"
#include "tokenlist.h"
#include "utils.h"
#include "valueptr.h"
#include "vfvalue.h"
#include <algorithm>
#include <array>
#include <cassert>
#include <chrono>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <exception>
#include <functional>
#include <initializer_list>
#include <iterator>
#include <limits>
#include <map>
#include <memory>
#include <set>
#include <sstream> // IWYU pragma: keep
#include <string>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <vector>
static void bailoutInternal(const std::string& type, const TokenList &tokenlist, ErrorLogger *errorLogger, const Token *tok, const std::string &what, const std::string &file, int line, std::string function)
{
if (function.find("operator") != std::string::npos)
function = "(valueFlow)";
std::list<ErrorMessage::FileLocation> callstack(1, ErrorMessage::FileLocation(tok, &tokenlist));
const std::string location = Path::stripDirectoryPart(file) + ":" + std::to_string(line) + ":";
ErrorMessage errmsg(callstack, tokenlist.getSourceFilePath(), Severity::debug,
(file.empty() ? "" : location) + function + " bailout: " + what, type, Certainty::normal);
errorLogger->reportErr(errmsg);
}
#define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __func__)
#define bailout(tokenlist, errorLogger, tok, what) bailout2("valueFlowBailout", tokenlist, errorLogger, tok, what)
#define bailoutIncompleteVar(tokenlist, errorLogger, tok, what) bailoutInternal("valueFlowBailoutIncompleteVar", tokenlist, errorLogger, tok, what, "", 0, __func__)
static std::string debugString(const ValueFlow::Value& v)
{
std::string kind;
switch (v.valueKind) {
case ValueFlow::Value::ValueKind::Impossible:
case ValueFlow::Value::ValueKind::Known:
kind = "always";
break;
case ValueFlow::Value::ValueKind::Inconclusive:
kind = "inconclusive";
break;
case ValueFlow::Value::ValueKind::Possible:
kind = "possible";
break;
}
return kind + " " + v.toString();
}
static void setSourceLocation(ValueFlow::Value& v,
SourceLocation ctx,
const Token* tok,
SourceLocation local = SourceLocation::current())
{
std::string file = ctx.file_name();
if (file.empty())
return;
std::string s = Path::stripDirectoryPart(file) + ":" + std::to_string(ctx.line()) + ": " + ctx.function_name() +
" => " + local.function_name() + ": " + debugString(v);
v.debugPath.emplace_back(tok, std::move(s));
}
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 bool isNonConditionalPossibleIntValue(const ValueFlow::Value& v)
{
if (v.conditional)
return false;
if (v.condition)
return false;
if (!v.isPossible())
return false;
if (!v.isIntValue())
return false;
return true;
}
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 setConditionalValue(ValueFlow::Value& value, const Token* tok, MathLib::bigint i)
{
assert(value.isIntValue());
value.intvalue = i;
value.assumeCondition(tok);
value.setPossible();
}
static void setConditionalValues(const Token* tok,
bool lhs,
MathLib::bigint value,
ValueFlow::Value& true_value,
ValueFlow::Value& false_value)
{
if (Token::Match(tok, "==|!=|>=|<=")) {
setConditionalValue(true_value, tok, value);
const char* greaterThan = ">=";
const char* lessThan = "<=";
if (lhs)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
setConditionalValue(false_value, tok, value - 1);
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
setConditionalValue(false_value, tok, value + 1);
} else {
setConditionalValue(false_value, tok, value);
}
} else {
const char* greaterThan = ">";
const char* lessThan = "<";
if (lhs)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
setConditionalValue(true_value, tok, value + 1);
setConditionalValue(false_value, tok, value);
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
setConditionalValue(true_value, tok, value - 1);
setConditionalValue(false_value, tok, value);
}
}
setValueBound(true_value, tok, lhs);
setValueBound(false_value, tok, !lhs);
}
static bool isSaturated(MathLib::bigint value)
{
return value == std::numeric_limits<MathLib::bigint>::max() || value == std::numeric_limits<MathLib::bigint>::min();
}
static void parseCompareEachInt(
const Token* tok,
const std::function<void(const Token* varTok, ValueFlow::Value true_value, ValueFlow::Value false_value)>& each,
const std::function<std::vector<ValueFlow::Value>(const Token*)>& evaluate)
{
if (!tok->astOperand1() || !tok->astOperand2())
return;
if (tok->isComparisonOp()) {
std::vector<ValueFlow::Value> value1 = evaluate(tok->astOperand1());
std::vector<ValueFlow::Value> value2 = evaluate(tok->astOperand2());
if (!value1.empty() && !value2.empty()) {
if (tok->astOperand1()->hasKnownIntValue())
value2.clear();
if (tok->astOperand2()->hasKnownIntValue())
value1.clear();
}
for (const ValueFlow::Value& v1 : value1) {
ValueFlow::Value true_value = v1;
ValueFlow::Value false_value = v1;
if (isSaturated(v1.intvalue) || astIsFloat(tok->astOperand2(), /*unknown*/ false))
continue;
setConditionalValues(tok, true, v1.intvalue, true_value, false_value);
each(tok->astOperand2(), std::move(true_value), std::move(false_value));
}
for (const ValueFlow::Value& v2 : value2) {
ValueFlow::Value true_value = v2;
ValueFlow::Value false_value = v2;
if (isSaturated(v2.intvalue) || astIsFloat(tok->astOperand1(), /*unknown*/ false))
continue;
setConditionalValues(tok, false, v2.intvalue, true_value, false_value);
each(tok->astOperand1(), std::move(true_value), std::move(false_value));
}
}
}
static void parseCompareEachInt(
const Token* tok,
const std::function<void(const Token* varTok, ValueFlow::Value true_value, ValueFlow::Value false_value)>& each)
{
parseCompareEachInt(tok, each, [](const Token* t) -> std::vector<ValueFlow::Value> {
if (t->hasKnownIntValue())
return {t->values().front()};
std::vector<ValueFlow::Value> result;
std::copy_if(t->values().cbegin(), t->values().cend(), std::back_inserter(result), [&](const ValueFlow::Value& v) {
if (v.path < 1)
return false;
if (!isNonConditionalPossibleIntValue(v))
return false;
return true;
});
return result;
});
}
const Token* ValueFlow::parseCompareInt(const Token* tok,
ValueFlow::Value& true_value,
ValueFlow::Value& false_value,
const std::function<std::vector<MathLib::bigint>(const Token*)>& evaluate)
{
const Token* result = nullptr;
parseCompareEachInt(
tok,
[&](const Token* vartok, ValueFlow::Value true_value2, ValueFlow::Value false_value2) {
if (result)
return;
result = vartok;
true_value = std::move(true_value2);
false_value = std::move(false_value2);
},
[&](const Token* t) -> std::vector<ValueFlow::Value> {
std::vector<ValueFlow::Value> r;
std::vector<MathLib::bigint> v = evaluate(t);
std::transform(v.cbegin(), v.cend(), std::back_inserter(r), [&](MathLib::bigint i) {
return ValueFlow::Value{i};
});
return r;
});
return result;
}
const Token *ValueFlow::parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value)
{
return parseCompareInt(tok, true_value, false_value, [](const Token* t) -> std::vector<MathLib::bigint> {
if (t->hasKnownIntValue())
return {t->values().front().intvalue};
return std::vector<MathLib::bigint>{};
});
}
static bool isEscapeScope(const Token* tok, const Settings* settings, 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 (settings->library.isScopeNoReturn(tok->link(), &unknownFunction))
return unknownFunction.empty() || unknown;
return false;
}
static ValueFlow::Value castValue(ValueFlow::Value value, const ValueType::Sign sign, nonneg int bit)
{
if (value.isFloatValue()) {
value.valueType = ValueFlow::Value::ValueType::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) {
constexpr 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 bool isNumeric(const ValueFlow::Value& value) {
return value.isIntValue() || value.isFloatValue();
}
void ValueFlow::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.tokvalue)
result.tokvalue = value1.tokvalue;
else if (value2.tokvalue)
result.tokvalue = value2.tokvalue;
if (value1.isSymbolicValue()) {
result.valueType = value1.valueType;
result.tokvalue = value1.tokvalue;
}
if (value2.isSymbolicValue()) {
result.valueType = value2.valueType;
result.tokvalue = value2.tokvalue;
}
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 != 0) ? 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, const Settings* settings)
{
// TODO: This might be a generic utility function?
if (!Token::Match(parent, "{|("))
return nullptr;
// Functional cast
if (parent->isBinaryOp() && Token::Match(parent->astOperand1(), "%type% (|{") &&
parent->astOperand1()->tokType() == Token::eType && astIsPrimitive(parent))
return parent->astOperand1();
if (parent->str() != "(")
return nullptr;
if (!parent->astOperand2() && Token::Match(parent, "( %name%|::")) {
const Token* ftok = parent->next();
if (ftok->isStandardType())
return ftok;
if (Token::simpleMatch(ftok, "::"))
ftok = ftok->next();
while (Token::Match(ftok, "%name% ::"))
ftok = ftok->tokAt(2);
if (settings->library.isNotLibraryFunction(ftok))
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;
}
// does the operation cause a loss of information?
static bool isNonInvertibleOperation(const Token* tok)
{
return !Token::Match(tok, "+|-");
}
static bool isComputableValue(const Token* parent, const ValueFlow::Value& value)
{
const bool noninvertible = isNonInvertibleOperation(parent);
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() || !Token::Match(value.tokvalue, "{|%str%")))
return false;
return true;
}
static Library::Container::Yield getContainerYield(Token* tok, const Settings* settings, Token** parent = nullptr)
{
if (Token::Match(tok, ". %name% (") && tok->astParent() == tok->tokAt(2) && tok->astOperand1() &&
tok->astOperand1()->valueType()) {
const Library::Container* c = getLibraryContainer(tok->astOperand1());
if (parent)
*parent = tok->astParent();
return c ? c->getYield(tok->strAt(1)) : Library::Container::Yield::NO_YIELD;
}
if (Token::Match(tok->previous(), "%name% (")) {
if (parent)
*parent = tok;
if (const Library::Function* f = settings->library.getFunction(tok->previous())) {
return f->containerYield;
}
}
return Library::Container::Yield::NO_YIELD;
}
/** Set token value for cast */
static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings);
static bool isCompatibleValueTypes(ValueFlow::Value::ValueType x, ValueFlow::Value::ValueType y)
{
static const std::unordered_map<ValueFlow::Value::ValueType,
std::unordered_set<ValueFlow::Value::ValueType, EnumClassHash>,
EnumClassHash>
compatibleTypes = {
{ValueFlow::Value::ValueType::INT,
{ValueFlow::Value::ValueType::FLOAT,
ValueFlow::Value::ValueType::SYMBOLIC,
ValueFlow::Value::ValueType::TOK}},
{ValueFlow::Value::ValueType::FLOAT, {ValueFlow::Value::ValueType::INT}},
{ValueFlow::Value::ValueType::TOK, {ValueFlow::Value::ValueType::INT}},
{ValueFlow::Value::ValueType::ITERATOR_START, {ValueFlow::Value::ValueType::INT}},
{ValueFlow::Value::ValueType::ITERATOR_END, {ValueFlow::Value::ValueType::INT}},
};
if (x == y)
return true;
auto it = compatibleTypes.find(x);
if (it == compatibleTypes.end())
return false;
return it->second.count(y) > 0;
}
static bool isCompatibleValues(const ValueFlow::Value& value1, const ValueFlow::Value& value2)
{
if (value1.isSymbolicValue() && value2.isSymbolicValue() && value1.tokvalue->exprId() != value2.tokvalue->exprId())
return false;
if (!isCompatibleValueTypes(value1.valueType, value2.valueType))
return false;
if (value1.isKnown() || value2.isKnown())
return true;
if (value1.isImpossible() || value2.isImpossible())
return false;
if (value1.varId == 0 || value2.varId == 0)
return true;
if (value1.varId == value2.varId && value1.varvalue == value2.varvalue && value1.isIntValue() && value2.isIntValue())
return true;
return false;
}
static ValueFlow::Value truncateImplicitConversion(Token* parent, const ValueFlow::Value& value, const Settings* settings)
{
if (!value.isIntValue() && !value.isFloatValue())
return value;
if (!parent)
return value;
if (!parent->isBinaryOp())
return value;
if (!parent->isConstOp())
return value;
if (!astIsIntegral(parent->astOperand1(), false))
return value;
if (!astIsIntegral(parent->astOperand2(), false))
return value;
const ValueType* vt1 = parent->astOperand1()->valueType();
const ValueType* vt2 = parent->astOperand2()->valueType();
// If the sign is the same there is no truncation
if (vt1->sign == vt2->sign)
return value;
const size_t n1 = ValueFlow::getSizeOf(*vt1, settings);
const size_t n2 = ValueFlow::getSizeOf(*vt2, settings);
ValueType::Sign sign = ValueType::Sign::UNSIGNED;
if (n1 < n2)
sign = vt2->sign;
else if (n1 > n2)
sign = vt1->sign;
ValueFlow::Value v = castValue(value, sign, std::max(n1, n2) * 8);
v.wideintvalue = value.intvalue;
return v;
}
/** set ValueFlow value and perform calculations if possible */
static void setTokenValue(Token* tok,
ValueFlow::Value value,
const Settings* settings,
SourceLocation loc = SourceLocation::current())
{
// Skip setting values that are too big since its ambiguous
if (!value.isImpossible() && value.isIntValue() && value.intvalue < 0 && astIsUnsigned(tok) &&
ValueFlow::getSizeOf(*tok->valueType(), settings) >= sizeof(MathLib::bigint))
return;
if (!value.isImpossible() && value.isIntValue())
value = truncateImplicitConversion(tok->astParent(), value, settings);
if (settings->debugnormal)
setSourceLocation(value, loc, tok);
if (!tok->addValue(value))
return;
if (value.path < 0)
return;
Token *parent = tok->astParent();
if (!parent)
return;
if (Token::simpleMatch(parent, ",") && !parent->isInitComma() && astIsRHS(tok)) {
const Token* callParent = findParent(parent, [](const Token* p) {
return !Token::simpleMatch(p, ",");
});
// Ensure that the comma isn't a function call
if (!callParent || (!Token::Match(callParent->previous(), "%name%|> (") && !Token::simpleMatch(callParent, "{") &&
(!Token::Match(callParent, "( %name%") || settings->library.isNotLibraryFunction(callParent->next())) &&
!(callParent->str() == "(" && (Token::simpleMatch(callParent->astOperand1(), "*") || Token::Match(callParent->astOperand1(), "%name%|("))))) {
setTokenValue(parent, std::move(value), settings);
return;
}
}
if (Token::simpleMatch(parent, "=") && astIsRHS(tok)) {
setTokenValue(parent, value, settings);
if (!value.isUninitValue())
return;
}
if (value.isContainerSizeValue() && astIsContainer(tok)) {
// .empty, .size, +"abc", +'a'
if (Token::Match(parent, "+|==|!=") && parent->astOperand1() && parent->astOperand2()) {
for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) {
if (value1.isImpossible())
continue;
for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) {
if (value2.isImpossible())
continue;
if (value1.path != value2.path)
continue;
ValueFlow::Value result;
if (Token::Match(parent, "%comp%"))
result.valueType = ValueFlow::Value::ValueType::INT;
else
result.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
if (value1.isContainerSizeValue() && value2.isContainerSizeValue())
result.intvalue = calculate(parent->str(), value1.intvalue, value2.intvalue);
else if (value1.isContainerSizeValue() && value2.isTokValue() && value2.tokvalue->tokType() == Token::eString)
result.intvalue = calculate(parent->str(), value1.intvalue, MathLib::bigint(Token::getStrLength(value2.tokvalue)));
else if (value2.isContainerSizeValue() && value1.isTokValue() && value1.tokvalue->tokType() == Token::eString)
result.intvalue = calculate(parent->str(), MathLib::bigint(Token::getStrLength(value1.tokvalue)), value2.intvalue);
else
continue;
combineValueProperties(value1, value2, result);
if (Token::simpleMatch(parent, "==") && result.intvalue)
continue;
if (Token::simpleMatch(parent, "!=") && !result.intvalue)
continue;
setTokenValue(parent, std::move(result), settings);
}
}
}
Token* next = nullptr;
const Library::Container::Yield yields = getContainerYield(parent, settings, &next);
if (yields == Library::Container::Yield::SIZE) {
ValueFlow::Value v(value);
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(next, std::move(v), settings);
} else if (yields == Library::Container::Yield::EMPTY) {
ValueFlow::Value v(value);
v.valueType = ValueFlow::Value::ValueType::INT;
v.bound = ValueFlow::Value::Bound::Point;
if (value.isImpossible()) {
if (value.intvalue == 0)
v.setKnown();
else if ((value.bound == ValueFlow::Value::Bound::Upper && value.intvalue > 0) ||
(value.bound == ValueFlow::Value::Bound::Lower && value.intvalue < 0)) {
v.intvalue = 0;
v.setKnown();
} else
v.setPossible();
} else {
v.intvalue = !v.intvalue;
}
setTokenValue(next, std::move(v), settings);
}
return;
}
if (value.isLifetimeValue()) {
if (!ValueFlow::isLifetimeBorrowed(parent, settings))
return;
if (value.lifetimeKind == ValueFlow::Value::LifetimeKind::Iterator && astIsIterator(parent)) {
setTokenValue(parent,std::move(value),settings);
} else if (astIsPointer(tok) && astIsPointer(parent) && !parent->isUnaryOp("*") &&
(parent->isArithmeticalOp() || parent->isCast())) {
setTokenValue(parent,std::move(value),settings);
}
return;
}
if (value.isUninitValue()) {
if (Token::Match(tok, ". %var%"))
setTokenValue(tok->next(), value, settings);
if (parent->isCast()) {
setTokenValue(parent, std::move(value), settings);
return;
}
ValueFlow::Value pvalue = value;
if (!value.subexpressions.empty() && Token::Match(parent, ". %var%")) {
if (contains(value.subexpressions, parent->next()->str()))
pvalue.subexpressions.clear();
else
return;
}
if (parent->isUnaryOp("&")) {
pvalue.indirect++;
setTokenValue(parent, std::move(pvalue), settings);
} else if (Token::Match(parent, ". %var%") && parent->astOperand1() == tok && parent->astOperand2()) {
if (parent->originalName() == "->" && pvalue.indirect > 0)
pvalue.indirect--;
setTokenValue(parent->astOperand2(), std::move(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(), std::move(pvalue), settings);
} else if (parent->isUnaryOp("*") && pvalue.indirect > 0) {
pvalue.indirect--;
setTokenValue(parent, std::move(pvalue), settings);
}
return;
}
// cast..
if (const Token *castType = getCastTypeStartToken(parent, settings)) {
if (contains({ValueFlow::Value::ValueType::INT, ValueFlow::Value::ValueType::SYMBOLIC}, value.valueType) &&
Token::simpleMatch(parent->astOperand1(), "dynamic_cast"))
return;
const ValueType &valueType = ValueType::parseDecl(castType, *settings);
if (value.isImpossible() && value.isIntValue() && value.intvalue < 0 && astIsUnsigned(tok) &&
valueType.sign == ValueType::SIGNED && tok->valueType() &&
ValueFlow::getSizeOf(*tok->valueType(), settings) >= ValueFlow::getSizeOf(valueType, settings))
return;
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.cbegin(), values.cend(), value) != values.cend())
setTokenValue(parent, value, settings);
}
} else if (!value.isImpossible()) {
// is condition only depending on 1 variable?
// cppcheck-suppress[variableScope] #8541
nonneg int varId = 0;
bool ret = false;
visitAstNodes(parent->astOperand1(),
[&](const Token *t) {
if (t->varId()) {
if (varId > 0 || value.varId != 0)
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();
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 = isNonInvertibleOperation(parent);
// 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, "[&*]") && astIsIntegral(parent, true) && value.isKnown() && value.isIntValue() &&
value.intvalue == 0) {
setTokenValue(parent, std::move(value), settings);
return;
}
// known result when a operand is true.
if (Token::simpleMatch(parent, "&&") && value.isKnown() && value.isIntValue() && value.intvalue==0) {
setTokenValue(parent, std::move(value), settings);
return;
}
// known result when a operand is false.
if (Token::simpleMatch(parent, "||") && value.isKnown() && value.isIntValue() && value.intvalue!=0) {
setTokenValue(parent, std::move(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 (!isCompatibleValues(value1, value2))
continue;
ValueFlow::Value result(0);
combineValueProperties(value1, value2, result);
if (astIsFloat(parent, false)) {
if (!result.isIntValue() && !result.isFloatValue())
continue;
result.valueType = ValueFlow::Value::ValueType::FLOAT;
}
const double floatValue1 = value1.isFloatValue() ? value1.floatValue : value1.intvalue;
const double floatValue2 = value2.isFloatValue() ? value2.floatValue : value2.intvalue;
const auto intValue1 = [&]() -> MathLib::bigint {
return value1.isFloatValue() ? static_cast<MathLib::bigint>(value1.floatValue) : value1.intvalue;
};
const auto intValue2 = [&]() -> MathLib::bigint {
return value2.isFloatValue() ? static_cast<MathLib::bigint>(value2.floatValue) : value2.intvalue;
};
if ((value1.isFloatValue() || value2.isFloatValue()) && Token::Match(parent, "&|^|%|<<|>>|==|!=|%or%"))
continue;
if (Token::Match(parent, "==|!=")) {
if ((value1.isIntValue() && value2.isTokValue()) || (value1.isTokValue() && value2.isIntValue())) {
if (parent->str() == "==")
result.intvalue = 0;
else if (parent->str() == "!=")
result.intvalue = 1;
} else if (value1.isIntValue() && value2.isIntValue()) {
bool error = false;
result.intvalue = calculate(parent->str(), intValue1(), intValue2(), &error);
if (error)
continue;
} else if (value1.isTokValue() && value2.isTokValue() &&
(astIsContainer(parent->astOperand1()) || astIsContainer(parent->astOperand2()))) {
const Token* tok1 = value1.tokvalue;
const Token* tok2 = value2.tokvalue;
bool equal = false;
if (Token::Match(tok1, "%str%") && Token::Match(tok2, "%str%")) {
equal = tok1->str() == tok2->str();
} else if (Token::simpleMatch(tok1, "{") && Token::simpleMatch(tok2, "{")) {
std::vector<const Token*> args1 = getArguments(tok1);
std::vector<const Token*> args2 = getArguments(tok2);
if (args1.size() == args2.size()) {
if (!std::all_of(args1.begin(), args1.end(), std::mem_fn(&Token::hasKnownIntValue)))
continue;
if (!std::all_of(args2.begin(), args2.end(), std::mem_fn(&Token::hasKnownIntValue)))
continue;
equal = std::equal(args1.begin(),
args1.end(),
args2.begin(),
[&](const Token* atok, const Token* btok) {
return atok->values().front().intvalue ==
btok->values().front().intvalue;
});
} else {
equal = false;
}
} else {
continue;
}
result.intvalue = parent->str() == "==" ? equal : !equal;
} else {
continue;
}
setTokenValue(parent, result, settings);
} else if (Token::Match(parent, "%op%")) {
if (Token::Match(parent, "%comp%")) {
if (!result.isFloatValue() && !value1.isIntValue() && !value2.isIntValue())
continue;
} else {
if (value1.isTokValue() || value2.isTokValue())
break;
}
bool error = false;
if (result.isFloatValue()) {
result.floatValue = calculate(parent->str(), floatValue1, floatValue2, &error);
} else {
result.intvalue = calculate(parent->str(), intValue1(), intValue2(), &error);
}
if (error)
continue;
// If the bound comes from the second value then invert the bound when subtracting
if (Token::simpleMatch(parent, "-") && value2.bound == result.bound &&
value2.bound != ValueFlow::Value::Bound::Point)
result.invertBound();
setTokenValue(parent, result, settings);
}
}
}
}
// !
else if (parent->str() == "!") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue())
continue;
if (val.isImpossible() && val.intvalue != 0)
continue;
ValueFlow::Value v(val);
if (val.isImpossible())
v.setKnown();
else
v.intvalue = !v.intvalue;
setTokenValue(parent, std::move(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 (tok->valueType() &&
tok->valueType()->sign == ValueType::Sign::UNSIGNED &&
tok->valueType()->pointer == 0) {
if (tok->valueType()->type == ValueType::Type::INT)
bits = settings->platform.int_bit;
else if (tok->valueType()->type == ValueType::Type::LONG)
bits = settings->platform.long_bit;
}
if (bits > 0 && bits < MathLib::bigint_bits)
v.intvalue &= (((MathLib::biguint)1)<<bits) - 1;
setTokenValue(parent, std::move(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()) {
if (v.intvalue == LLONG_MIN)
// Value can't be inverted
continue;
v.intvalue = -v.intvalue;
} else
v.floatValue = -v.floatValue;
v.invertBound();
setTokenValue(parent, std::move(v), settings);
}
}
// increment
else if (parent->str() == "++") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue() && !val.isSymbolicValue())
continue;
ValueFlow::Value v(val);
if (parent == tok->previous()) {
if (v.isIntValue() || v.isSymbolicValue())
v.intvalue = v.intvalue + 1;
else
v.floatValue = v.floatValue + 1.0;
}
setTokenValue(parent, std::move(v), settings);
}
}
// decrement
else if (parent->str() == "--") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue() && !val.isSymbolicValue())
continue;
ValueFlow::Value v(val);
if (parent == tok->previous()) {
if (v.isIntValue() || v.isSymbolicValue())
v.intvalue = v.intvalue - 1;
else
v.floatValue = v.floatValue - 1.0;
}
setTokenValue(parent, std::move(v), settings);
}
}
// C++ init
else if (parent->str() == "{" && Token::simpleMatch(parent->previous(), "= {") && Token::simpleMatch(parent->link(), "} ;")) {
const Token* lhs = parent->previous()->astOperand1();
if (lhs && lhs->valueType()) {
if (lhs->valueType()->isIntegral() || lhs->valueType()->isFloat() || (lhs->valueType()->pointer > 0 && value.isIntValue())) {
setTokenValue(parent, value, settings);
}
}
}
else if (Token::Match(parent, ":: %name%") && parent->astOperand2() == tok) {
setTokenValue(parent, value, settings);
}
// Calling std::size or std::empty on an array
else if (value.isTokValue() && Token::simpleMatch(value.tokvalue, "{") && tok->variable() &&
tok->variable()->isArray() && Token::Match(parent->previous(), "%name% (") && astIsRHS(tok)) {
std::vector<const Token*> args = getArguments(value.tokvalue);
if (const Library::Function* f = settings->library.getFunction(parent->previous())) {
if (f->containerYield == Library::Container::Yield::SIZE) {
ValueFlow::Value v(value);
v.valueType = ValueFlow::Value::ValueType::INT;
v.intvalue = args.size();
setTokenValue(parent, std::move(v), settings);
} else if (f->containerYield == Library::Container::Yield::EMPTY) {
ValueFlow::Value v(value);
v.intvalue = args.empty();
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(parent, std::move(v), settings);
}
}
}
}
static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings)
{
if (valueType.pointer || value.isImpossible())
setTokenValue(parent,value,settings);
else if (valueType.type == ValueType::Type::CHAR)
setTokenValue(parent, castValue(value, valueType.sign, settings->platform.char_bit), settings);
else if (valueType.type == ValueType::Type::SHORT)
setTokenValue(parent, castValue(value, valueType.sign, settings->platform.short_bit), settings);
else if (valueType.type == ValueType::Type::INT)
setTokenValue(parent, castValue(value, valueType.sign, settings->platform.int_bit), settings);
else if (valueType.type == ValueType::Type::LONG)
setTokenValue(parent, castValue(value, valueType.sign, settings->platform.long_bit), settings);
else if (valueType.type == ValueType::Type::LONGLONG)
setTokenValue(parent, castValue(value, valueType.sign, settings->platform.long_long_bit), settings);
else if (valueType.isFloat() && isNumeric(value)) {
ValueFlow::Value floatValue = value;
floatValue.valueType = ValueFlow::Value::ValueType::FLOAT;
if (value.isIntValue())
floatValue.floatValue = value.intvalue;
setTokenValue(parent, std::move(floatValue), settings);
} else if (value.isIntValue()) {
const long long charMax = settings->platform.signedCharMax();
const long long charMin = settings->platform.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);
return ValueFlow::getSizeOf(valueType, settings);
}
size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings *settings)
{
if (vt.pointer)
return settings->platform.sizeof_pointer;
if (vt.type == ValueType::Type::BOOL || vt.type == ValueType::Type::CHAR)
return 1;
if (vt.type == ValueType::Type::SHORT)
return settings->platform.sizeof_short;
if (vt.type == ValueType::Type::WCHAR_T)
return settings->platform.sizeof_wchar_t;
if (vt.type == ValueType::Type::INT)
return settings->platform.sizeof_int;
if (vt.type == ValueType::Type::LONG)
return settings->platform.sizeof_long;
if (vt.type == ValueType::Type::LONGLONG)
return settings->platform.sizeof_long_long;
if (vt.type == ValueType::Type::FLOAT)
return settings->platform.sizeof_float;
if (vt.type == ValueType::Type::DOUBLE)
return settings->platform.sizeof_double;
if (vt.type == ValueType::Type::LONGDOUBLE)
return settings->platform.sizeof_long_double;
return 0;
}
static bool getMinMaxValues(const ValueType* vt, const Platform& platform, MathLib::bigint& minValue, MathLib::bigint& maxValue);
// Handle various constants..
static Token * valueFlowSetConstantValue(Token *tok, const Settings *settings, bool cpp)
{
if ((tok->isNumber() && MathLib::isInt(tok->str())) || (tok->tokType() == Token::eChar)) {
try {
MathLib::bigint signedValue = MathLib::toBigNumber(tok->str());
const ValueType* vt = tok->valueType();
if (vt && vt->sign == ValueType::UNSIGNED && signedValue < 0 && ValueFlow::getSizeOf(*vt, settings) < sizeof(MathLib::bigint)) {
MathLib::bigint minValue{}, maxValue{};
if (getMinMaxValues(tok->valueType(), settings->platform, minValue, maxValue))
signedValue += maxValue + 1;
}
ValueFlow::Value value(signedValue);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, std::move(value), settings);
} catch (const std::exception & /*e*/) {
// Bad character literal
}
} else if (tok->isNumber() && MathLib::isFloat(tok->str())) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::FLOAT;
value.floatValue = MathLib::toDoubleNumber(tok->str());
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, std::move(value), settings);
} else if (tok->enumerator() && tok->enumerator()->value_known) {
ValueFlow::Value value(tok->enumerator()->value);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, std::move(value), settings);
} else if (tok->str() == "NULL" || (cpp && tok->str() == "nullptr")) {
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, std::move(value), settings);
} else if (Token::simpleMatch(tok, "sizeof (")) {
if (tok->next()->astOperand2() && !tok->next()->astOperand2()->isLiteral() && tok->next()->astOperand2()->valueType() &&
(tok->next()->astOperand2()->valueType()->pointer == 0 || // <- TODO this is a bailout, abort when there are array->pointer conversions
(tok->next()->astOperand2()->variable() && !tok->next()->astOperand2()->variable()->isArray())) &&
!tok->next()->astOperand2()->valueType()->isEnum()) { // <- TODO this is a bailout, handle enum with non-int types
const size_t sz = ValueFlow::getSizeOf(*tok->next()->astOperand2()->valueType(), settings);
if (sz) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
return tok->linkAt(1);
}
}
const Token *tok2 = tok->tokAt(2);
// skip over tokens to find variable or type
while (tok2 && !tok2->isStandardType() && 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->platform.type != Platform::Type::Unspecified)
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
}
} else if (tok2->enumerator() && tok2->enumerator()->scope) {
long long size = settings->platform.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->platform.type != Platform::Type::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), std::move(value), settings);
} else if (tok2->type() && tok2->type()->isEnumType()) {
long long size = settings->platform.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->platform.type != Platform::Type::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), std::move(value), settings);
} else if (Token::Match(tok, "sizeof ( %var% ) /") && tok->next()->astParent() == tok->tokAt(4) &&
tok->tokAt(4)->astOperand2() && Token::simpleMatch(tok->tokAt(4)->astOperand2()->previous(), "sizeof (")) {
// Get number of elements in array
const Token *sz1 = tok->tokAt(2);
const Token *sz2 = tok->tokAt(4)->astOperand2(); // left parenthesis of sizeof on rhs
const nonneg int varid1 = sz1->varId();
if (varid1 &&
sz1->variable() &&
sz1->variable()->isArray() &&
!sz1->variable()->dimensions().empty() &&
sz1->variable()->dimensionKnown(0) &&
Token::Match(sz2->astOperand2(), "*|[") && Token::Match(sz2->astOperand2()->astOperand1(), "%varid%", varid1)) {
ValueFlow::Value value(sz1->variable()->dimension(0));
if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified)
value.setKnown();
setTokenValue(tok->tokAt(4), std::move(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->platform.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->platform.type != Platform::Type::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), std::move(value), settings);
}
}
} else if (tok2->tokType() == Token::eString) {
const size_t sz = Token::getStrSize(tok2, settings);
if (sz > 0) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(tok->next(), std::move(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->platform.sizeof_wchar_t;
else if ((tok2->isCChar() && !cpp) || (tok2->isCMultiChar()))
sz = settings->platform.sizeof_int;
else
sz = 1;
if (sz > 0) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
}
} else if (!tok2->type()) {
const ValueType& vt = ValueType::parseDecl(tok2, *settings);
size_t sz = ValueFlow::getSizeOf(vt, settings);
const Token* brac = tok2->astParent();
while (Token::simpleMatch(brac, "[")) {
const Token* num = brac->astOperand2();
if (num && ((num->isNumber() && MathLib::isInt(num->str())) || num->tokType() == Token::eChar)) {
try {
const MathLib::biguint dim = MathLib::toBigUNumber(num->str());
sz *= dim;
brac = brac->astParent();
continue;
}
catch (const std::exception& /*e*/) {
// Bad integer literal
}
}
sz = 0;
break;
}
if (sz > 0) {
ValueFlow::Value value(sz);
if (!tok2->isTemplateArg() && settings->platform.type != Platform::Type::Unspecified)
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
}
}
// skip over enum
tok = tok->linkAt(1);
} else if (Token::Match(tok, "%name% [{(] [)}]") && (tok->isStandardType() ||
(tok->variable() && tok->variable()->nameToken() == tok &&
(tok->variable()->isPointer() || (tok->variable()->valueType() && tok->variable()->valueType()->isIntegral()))))) {
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
} else if (Token::simpleMatch(tok, "= { } ;")) {
const Token* lhs = tok->astOperand1();
if (lhs && lhs->valueType() && (lhs->valueType()->isIntegral() || lhs->valueType()->pointer > 0)) {
ValueFlow::Value value(0);
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
}
}
return tok->next();
}
static void valueFlowNumber(TokenList &tokenlist, const Settings* settings)
{
for (Token *tok = tokenlist.front(); tok;) {
tok = valueFlowSetConstantValue(tok, settings, 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, std::move(value), settings);
} 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(), std::move(value), settings);
}
}
}
}
static void valueFlowString(TokenList &tokenlist, const Settings* settings)
{
for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->tokType() == Token::eString) {
ValueFlow::Value strvalue;
strvalue.valueType = ValueFlow::Value::ValueType::TOK;
strvalue.tokvalue = tok;
strvalue.setKnown();
setTokenValue(tok, std::move(strvalue), settings);
}
}
}
static void valueFlowArray(TokenList &tokenlist, const Settings *settings)
{
std::map<nonneg int, const Token *> constantArrays;
for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->varId() > 0) {
// array
const std::map<nonneg int, const Token *>::const_iterator it = constantArrays.find(tok->varId());
if (it != constantArrays.end()) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = it->second;
value.setKnown();
setTokenValue(tok, std::move(value), settings);
}
// const array decl
else if (tok->variable() && tok->variable()->isArray() && tok->variable()->isConst() &&
tok->variable()->nameToken() == tok && Token::Match(tok, "%var% [ %num%| ] = {")) {
Token* rhstok = tok->next()->link()->tokAt(2);
constantArrays[tok->varId()] = rhstok;
tok = rhstok->link();
}
// pointer = array
else if (tok->variable() && tok->variable()->isArray() && Token::simpleMatch(tok->astParent(), "=") &&
astIsRHS(tok) && tok->astParent()->astOperand1() &&
tok->astParent()->astOperand1()->variable() &&
tok->astParent()->astOperand1()->variable()->isPointer()) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = tok;
value.setKnown();
setTokenValue(tok, std::move(value), settings);
}
continue;
}
if (Token::Match(tok, "const %type% %var% [ %num%| ] = {")) {
Token *vartok = tok->tokAt(2);
Token *rhstok = vartok->next()->link()->tokAt(2);
constantArrays[vartok->varId()] = rhstok;
tok = rhstok->link();
continue;
}
if (Token::Match(tok, "const char %var% [ %num%| ] = %str% ;")) {
Token *vartok = tok->tokAt(2);
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, const Settings *settings)
{
for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
const Variable *var = nullptr;
bool known = false;
const std::list<ValueFlow::Value>::const_iterator val =
std::find_if(tok->values().cbegin(), tok->values().cend(), 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, std::move(value), settings);
}
}
}
static void valueFlowArrayElement(TokenList& tokenlist, const Settings* settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
const Token* indexTok = nullptr;
const Token* arrayTok = nullptr;
if (Token::simpleMatch(tok, "[") && tok->isBinaryOp()) {
indexTok = tok->astOperand2();
arrayTok = tok->astOperand1();
} else if (Token::Match(tok->tokAt(-2), ". %name% (") && astIsContainer(tok->tokAt(-2)->astOperand1())) {
arrayTok = tok->tokAt(-2)->astOperand1();
const Library::Container* container = getLibraryContainer(arrayTok);
if (!container || container->stdAssociativeLike)
continue;
const Library::Container::Yield yield = container->getYield(tok->strAt(-1));
if (yield != Library::Container::Yield::AT_INDEX)
continue;
indexTok = tok->astOperand2();
}
if (!indexTok || !arrayTok)
continue;
for (const ValueFlow::Value& arrayValue : arrayTok->values()) {
if (!arrayValue.isTokValue())
continue;
if (arrayValue.isImpossible())
continue;
for (const ValueFlow::Value& indexValue : indexTok->values()) {
if (!indexValue.isIntValue())
continue;
if (indexValue.isImpossible())
continue;
if (!arrayValue.isKnown() && !indexValue.isKnown() && arrayValue.varId != 0 && indexValue.varId != 0 &&
!(arrayValue.varId == indexValue.varId && arrayValue.varvalue == indexValue.varvalue))
continue;
ValueFlow::Value result(0);
result.condition = arrayValue.condition ? arrayValue.condition : indexValue.condition;
result.setInconclusive(arrayValue.isInconclusive() || indexValue.isInconclusive());
result.varId = (arrayValue.varId != 0) ? arrayValue.varId : indexValue.varId;
result.varvalue = (result.varId == arrayValue.varId) ? arrayValue.intvalue : indexValue.intvalue;
if (arrayValue.valueKind == indexValue.valueKind)
result.valueKind = arrayValue.valueKind;
result.errorPath.insert(result.errorPath.end(), arrayValue.errorPath.cbegin(), arrayValue.errorPath.cend());
result.errorPath.insert(result.errorPath.end(), indexValue.errorPath.cbegin(), indexValue.errorPath.cend());
const MathLib::bigint index = indexValue.intvalue;
if (arrayValue.tokvalue->tokType() == Token::eString) {
const std::string s = arrayValue.tokvalue->strValue();
if (index == s.size()) {
result.intvalue = 0;
setTokenValue(tok, result, settings);
} else if (index >= 0 && index < s.size()) {
result.intvalue = s[index];
setTokenValue(tok, result, settings);
}
} else if (Token::simpleMatch(arrayValue.tokvalue, "{")) {
std::vector<const Token*> args = getArguments(arrayValue.tokvalue);
if (index < 0 || index >= args.size())
continue;
const Token* arg = args[index];
if (!arg->hasKnownIntValue())
continue;
const ValueFlow::Value& v = arg->values().front();
result.intvalue = v.intvalue;
result.errorPath.insert(result.errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend());
setTokenValue(tok, result, settings);
}
}
}
}
}
static void valueFlowPointerAlias(TokenList &tokenlist, const Settings* settings)
{
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::ValueType::TOK;
value.tokvalue = tok;
setTokenValue(tok, std::move(value), settings);
}
}
static void valueFlowBitAnd(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;
MathLib::bigint number;
if (MathLib::isInt(tok->astOperand1()->str()))
number = MathLib::toBigNumber(tok->astOperand1()->str());
else if (MathLib::isInt(tok->astOperand2()->str()))
number = MathLib::toBigNumber(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), settings);
setTokenValue(tok, ValueFlow::Value(number), settings);
}
}
}
static void valueFlowSameExpressions(TokenList &tokenlist, const Settings* settings)
{
for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
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(), settings->library, true, true, &val.errorPath)) {
setTokenValue(tok, std::move(val), settings);
}
}
}
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];
const bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
const 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;
const 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->platform.int_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONG)
lhsbits = settings->platform.long_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONGLONG)
lhsbits = settings->platform.long_long_bit;
else
continue;
if (rhsvalue >= lhsbits || rhsvalue >= MathLib::bigint_bits || (1ULL << rhsvalue) <= lhsmax)
continue;
ValueFlow::Value val(0);
val.setKnown();
setTokenValue(tok, std::move(val), settings);
}
}
static std::vector<MathLib::bigint> minUnsignedValue(const Token* tok, int depth = 8)
{
std::vector<MathLib::bigint> result;
if (!tok)
return result;
if (depth < 0)
return result;
if (tok->hasKnownIntValue()) {
result = {tok->values().front().intvalue};
} else if (!Token::Match(tok, "-|%|&|^") && tok->isConstOp() && tok->astOperand1() && tok->astOperand2()) {
std::vector<MathLib::bigint> op1 = minUnsignedValue(tok->astOperand1(), depth - 1);
std::vector<MathLib::bigint> op2 = minUnsignedValue(tok->astOperand2(), depth - 1);
if (!op1.empty() && !op2.empty()) {
result = calculate<std::vector<MathLib::bigint>>(tok->str(), op1.front(), op2.front());
}
}
if (result.empty() && astIsUnsigned(tok))
result = {0};
return result;
}
static bool isConvertedToIntegral(const Token* tok, const Settings* settings)
{
if (!tok)
return false;
std::vector<ValueType> parentTypes = getParentValueTypes(tok, settings);
if (parentTypes.empty())
return false;
const ValueType& vt = parentTypes.front();
return vt.type != ValueType::UNKNOWN_INT && vt.isIntegral();
}
static bool isSameToken(const Token* tok1, const Token* tok2)
{
if (!tok1 || !tok2)
return false;
if (tok1->exprId() != 0 && tok1->exprId() == tok2->exprId())
return true;
if (tok1->hasKnownIntValue() && tok2->hasKnownIntValue())
return tok1->values().front().intvalue == tok2->values().front().intvalue;
return false;
}
static void valueFlowImpossibleValues(TokenList& tokenList, const Settings* settings)
{
for (Token* tok = tokenList.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
if (Token::Match(tok, "true|false"))
continue;
if (astIsBool(tok) || Token::Match(tok, "%comp%")) {
ValueFlow::Value lower{-1};
lower.bound = ValueFlow::Value::Bound::Upper;
lower.setImpossible();
setTokenValue(tok, std::move(lower), settings);
ValueFlow::Value upper{2};
upper.bound = ValueFlow::Value::Bound::Lower;
upper.setImpossible();
setTokenValue(tok, std::move(upper), settings);
} else if (astIsUnsigned(tok) && !astIsPointer(tok)) {
std::vector<MathLib::bigint> minvalue = minUnsignedValue(tok);
if (minvalue.empty())
continue;
ValueFlow::Value value{std::max<MathLib::bigint>(0, minvalue.front()) - 1};
value.bound = ValueFlow::Value::Bound::Upper;
value.setImpossible();
setTokenValue(tok, std::move(value), settings);
}
if (Token::simpleMatch(tok, "?") && Token::Match(tok->astOperand1(), "<|<=|>|>=")) {
const Token* condTok = tok->astOperand1();
const Token* branchesTok = tok->astOperand2();
auto tokens = makeArray(condTok->astOperand1(), condTok->astOperand2());
auto branches = makeArray(branchesTok->astOperand1(), branchesTok->astOperand2());
bool flipped = false;
if (std::equal(tokens.cbegin(), tokens.cend(), branches.crbegin(), &isSameToken))
flipped = true;
else if (!std::equal(tokens.cbegin(), tokens.cend(), branches.cbegin(), &isSameToken))
continue;
const bool isMin = Token::Match(condTok, "<|<=") ^ flipped;
std::vector<ValueFlow::Value> values;
for (const Token* tok2 : tokens) {
if (tok2->hasKnownIntValue()) {
values.emplace_back(tok2->values().front());
} else {
ValueFlow::Value symValue{};
symValue.valueType = ValueFlow::Value::ValueType::SYMBOLIC;
symValue.tokvalue = tok2;
values.push_back(symValue);
std::copy_if(tok2->values().cbegin(),
tok2->values().cend(),
std::back_inserter(values),
[](const ValueFlow::Value& v) {
if (!v.isKnown())
return false;
return v.isSymbolicValue();
});
}
}
for (ValueFlow::Value& value : values) {
value.setImpossible();
if (isMin) {
value.intvalue++;
value.bound = ValueFlow::Value::Bound::Lower;
} else {
value.intvalue--;
value.bound = ValueFlow::Value::Bound::Upper;
}
setTokenValue(tok, std::move(value), settings);
}
} else if (Token::simpleMatch(tok, "%") && tok->astOperand2() && tok->astOperand2()->hasKnownIntValue()) {
ValueFlow::Value value{tok->astOperand2()->values().front()};
value.bound = ValueFlow::Value::Bound::Lower;
value.setImpossible();
setTokenValue(tok, std::move(value), settings);
} else if (Token::Match(tok, "abs|labs|llabs|fabs|fabsf|fabsl (")) {
ValueFlow::Value value{-1};
value.bound = ValueFlow::Value::Bound::Upper;
value.setImpossible();
setTokenValue(tok->next(), std::move(value), settings);
} else if (Token::Match(tok, ". data|c_str (") && astIsContainerOwned(tok->astOperand1())) {
const Library::Container* container = getLibraryContainer(tok->astOperand1());
if (!container)
continue;
if (!container->stdStringLike)
continue;
if (container->view)
continue;
ValueFlow::Value value{0};
value.setImpossible();
setTokenValue(tok->tokAt(2), std::move(value), settings);
} else if (Token::Match(tok, "make_shared|make_unique <") && Token::simpleMatch(tok->linkAt(1), "> (")) {
ValueFlow::Value value{0};
value.setImpossible();
setTokenValue(tok->linkAt(1)->next(), std::move(value), settings);
} else if ((tokenList.isCPP() && Token::simpleMatch(tok, "this")) || tok->isUnaryOp("&")) {
ValueFlow::Value value{0};
value.setImpossible();
setTokenValue(tok, std::move(value), settings);
} else if (tok->isIncompleteVar() && tok->astParent() && tok->astParent()->isUnaryOp("-") &&
isConvertedToIntegral(tok->astParent(), settings)) {
ValueFlow::Value value{0};
value.setImpossible();
setTokenValue(tok, std::move(value), settings);
}
}
}
static void valueFlowEnumValue(SymbolDatabase & symboldatabase, const Settings * settings)
{
for (Scope & scope : symboldatabase.scopeList) {
if (scope.type != Scope::eEnum)
continue;
MathLib::bigint value = 0;
bool prev_enum_is_known = true;
for (Enumerator & enumerator : scope.enumeratorList) {
if (enumerator.start) {
Token* rhs = const_cast<Token*>(enumerator.start->previous()->astOperand2());
ValueFlow::valueFlowConstantFoldAST(rhs, settings);
if (rhs && rhs->hasKnownIntValue()) {
enumerator.value = rhs->values().front().intvalue;
enumerator.value_known = true;
value = enumerator.value + 1;
prev_enum_is_known = true;
} else
prev_enum_is_known = false;
} else if (prev_enum_is_known) {
enumerator.value = value++;
enumerator.value_known = true;
}
}
}
}
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;
const 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;
const std::map<const Variable *, ValueFlow::Value>::const_iterator var = vars.find(tok->variable());
if (var == vars.end())
continue;
setTokenValue(tok, var->second, settings);
}
}
static ValuePtr<Analyzer> makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings);
static ValuePtr<Analyzer> makeReverseAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings);
static Analyzer::Result valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
ValueFlow::Value value,
const TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current())
{
if (settings->debugnormal)
setSourceLocation(value, loc, startToken);
return valueFlowGenericForward(startToken,
endToken,
makeAnalyzer(exprTok, std::move(value), tokenlist, settings),
*settings);
}
static Analyzer::Result valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
const TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current())
{
Analyzer::Result result{};
for (ValueFlow::Value& v : values) {
result.update(valueFlowForward(startToken, endToken, exprTok, std::move(v), tokenlist, settings, loc));
}
return result;
}
template<class ValueOrValues>
static Analyzer::Result valueFlowForward(Token* startToken,
const Token* exprTok,
ValueOrValues v,
TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current())
{
const Token* endToken = nullptr;
const Function* f = Scope::nestedInFunction(startToken->scope());
if (f && f->functionScope)
endToken = f->functionScope->bodyEnd;
return valueFlowForward(startToken, endToken, exprTok, std::move(v), tokenlist, settings, loc);
}
static Analyzer::Result valueFlowForwardRecursive(Token* top,
const Token* exprTok,
std::list<ValueFlow::Value> values,
const TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current())
{
Analyzer::Result result{};
for (ValueFlow::Value& v : values) {
if (settings->debugnormal)
setSourceLocation(v, loc, top);
result.update(
valueFlowGenericForward(top, makeAnalyzer(exprTok, std::move(v), tokenlist, settings), *settings));
}
return result;
}
static void valueFlowReverse(Token* tok,
const Token* const endToken,
const Token* const varToken,
std::list<ValueFlow::Value> values,
const TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current())
{
for (ValueFlow::Value& v : values) {
if (settings->debugnormal)
setSourceLocation(v, loc, tok);
valueFlowGenericReverse(tok, endToken, makeReverseAnalyzer(varToken, std::move(v), tokenlist, settings), *settings);
}
}
// Deprecated
static void valueFlowReverse(const TokenList& tokenlist,
Token* tok,
const Token* const varToken,
ValueFlow::Value val,
const ValueFlow::Value& val2,
ErrorLogger* /*errorLogger*/,
const Settings* settings = nullptr,
SourceLocation loc = SourceLocation::current())
{
std::list<ValueFlow::Value> values = {std::move(val)};
if (val2.varId != 0)
values.push_back(val2);
valueFlowReverse(tok, nullptr, varToken, std::move(values), tokenlist, settings, loc);
}
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->isCast()))
parent = parent->astParent();
const Token* top = tok->astTop();
if (top && Token::Match(top->previous(), "if|while|for ("))
return parent == top || Token::simpleMatch(parent, ";");
return parent && parent->str() != op;
}
static const std::string& invertAssign(const std::string& assign)
{
static std::unordered_map<std::string, std::string> lookup = {{"=", "="},
{"+=", "-="},
{"-=", "+="},
{"*=", "/="},
{"/=", "*="},
{"<<=", ">>="},
{">>=", "<<="},
{"^=", "^="}};
auto it = lookup.find(assign);
if (it == lookup.end()) {
return emptyString;
}
return it->second;
}
static std::string removeAssign(const std::string& assign) {
return std::string{assign.cbegin(), assign.cend() - 1};
}
template<class T, class U>
static T calculateAssign(const std::string& assign, const T& x, const U& y, bool* error = nullptr)
{
if (assign.empty() || assign.back() != '=') {
if (error)
*error = true;
return T{};
}
if (assign == "=")
return y;
return calculate<T, T>(removeAssign(assign), x, y, error);
}
template<class T, class U>
static void assignValueIfMutable(T& x, const U& y)
{
x = y;
}
template<class T, class U>
static void assignValueIfMutable(const T& /*unused*/, const U& /*unused*/)
{}
template<class Value, REQUIRES("Value must ValueFlow::Value", std::is_convertible<Value&, const ValueFlow::Value&> )>
static bool evalAssignment(Value& lhsValue, const std::string& assign, const ValueFlow::Value& rhsValue)
{
bool error = false;
if (lhsValue.isSymbolicValue() && rhsValue.isIntValue()) {
if (assign != "+=" && assign != "-=")
return false;
assignValueIfMutable(lhsValue.intvalue, calculateAssign(assign, lhsValue.intvalue, rhsValue.intvalue, &error));
} else if (lhsValue.isIntValue() && rhsValue.isIntValue()) {
assignValueIfMutable(lhsValue.intvalue, calculateAssign(assign, lhsValue.intvalue, rhsValue.intvalue, &error));
} else if (lhsValue.isFloatValue() && rhsValue.isIntValue()) {
assignValueIfMutable(lhsValue.floatValue,
calculateAssign(assign, lhsValue.floatValue, rhsValue.intvalue, &error));
} else {
return false;
}
return !error;
}
static ValueFlow::Value::MoveKind isMoveOrForward(const Token* tok)
{
if (!tok)
return ValueFlow::Value::MoveKind::NonMovedVariable;
const Token* parent = tok->astParent();
if (!Token::simpleMatch(parent, "("))
return ValueFlow::Value::MoveKind::NonMovedVariable;
const Token* ftok = parent->astOperand1();
if (!ftok)
return ValueFlow::Value::MoveKind::NonMovedVariable;
if (Token::simpleMatch(ftok->astOperand1(), "std :: move"))
return ValueFlow::Value::MoveKind::MovedVariable;
if (Token::simpleMatch(ftok->astOperand1(), "std :: forward"))
return ValueFlow::Value::MoveKind::ForwardedVariable;
// TODO: Check for cast
return ValueFlow::Value::MoveKind::NonMovedVariable;
}
template<class T>
struct SingleRange {
T* x;
T* begin() const {
return x;
}
T* end() const {
return x+1;
}
};
template<class T>
static SingleRange<T> MakeSingleRange(T& x)
{
return {&x};
}
class SelectValueFromVarIdMapRange {
using M = std::unordered_map<nonneg int, ValueFlow::Value>;
struct Iterator {
using iterator_category = std::forward_iterator_tag;
using value_type = const ValueFlow::Value;
using pointer = value_type *;
using reference = value_type &;
using difference_type = std::ptrdiff_t;
explicit Iterator(const M::const_iterator & it)
: mIt(it) {}
reference operator*() const {
return mIt->second;
}
pointer operator->() const {
return &mIt->second;
}
Iterator &operator++() {
// cppcheck-suppress postfixOperator - forward iterator needs to perform post-increment
mIt++;
return *this;
}
friend bool operator==(const Iterator &a, const Iterator &b) {
return a.mIt == b.mIt;
}
friend bool operator!=(const Iterator &a, const Iterator &b) {
return a.mIt != b.mIt;
}
private:
M::const_iterator mIt;
};
public:
explicit SelectValueFromVarIdMapRange(const M *m)
: mMap(m) {}
Iterator begin() const {
return Iterator(mMap->begin());
}
Iterator end() const {
return Iterator(mMap->end());
}
private:
const M *mMap;
};
// Check if its an alias of the variable or is being aliased to this variable
template<typename V>
static bool isAliasOf(const Variable * var, const Token *tok, nonneg int varid, const V& values, bool* inconclusive = nullptr)
{
if (tok->varId() == varid)
return false;
if (tok->varId() == 0)
return false;
if (isAliasOf(tok, varid, inconclusive))
return true;
if (var && !var->isPointer())
return false;
// Search through non value aliases
return std::any_of(values.begin(), values.end(), [&](const ValueFlow::Value& val) {
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;
return astHasVar(val.tokvalue, tok->varId());
});
}
static bool bifurcate(const Token* tok, const std::set<nonneg int>& varids, const Settings* settings, int depth = 20);
static bool bifurcateVariableChanged(const Variable* var,
const std::set<nonneg int>& varids,
const Token* start,
const Token* end,
const Settings* settings,
int depth = 20)
{
bool result = false;
const Token* tok = start;
while ((tok = findVariableChanged(
tok->next(), end, var->isPointer(), var->declarationId(), var->isGlobal(), settings, true))) {
if (Token::Match(tok->astParent(), "%assign%")) {
if (!bifurcate(tok->astParent()->astOperand2(), varids, settings, depth - 1))
return true;
} else {
result = true;
}
}
return result;
}
static bool bifurcate(const Token* tok, const std::set<nonneg int>& varids, const Settings* settings, int depth)
{
if (depth < 0)
return false;
if (!tok)
return true;
if (tok->hasKnownIntValue())
return true;
if (tok->isConstOp())
return bifurcate(tok->astOperand1(), varids, settings, depth) && bifurcate(tok->astOperand2(), varids, settings, depth);
if (tok->varId() != 0) {
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() || !bifurcateVariableChanged(var, varids, start, tok, settings, depth))
return var->isArgument() || bifurcate(start->astOperand2(), varids, settings, depth - 1);
return false;
}
return false;
}
struct ValueFlowAnalyzer : Analyzer {
const TokenList& tokenlist;
const Settings* settings;
ProgramMemoryState pms;
explicit ValueFlowAnalyzer(const TokenList& t, const Settings* s = nullptr) : tokenlist(t), settings(s), pms(settings) {}
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 internalMatch(const Token* /*tok*/) const {
return false;
}
virtual bool isAlias(const Token* tok, bool& inconclusive) const = 0;
using ProgramState = ProgramMemory::Map;
virtual ProgramState getProgramState() const = 0;
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 dependsOnThis() const {
return false;
}
virtual bool isVariable() const {
return false;
}
bool isCPP() const {
return tokenlist.isCPP();
}
const Settings* getSettings() const {
return settings;
}
// Returns Action::Match if its an exact match, return Action::Read if it partially matches the lifetime
Action analyzeLifetime(const Token* tok) const
{
if (!tok)
return Action::None;
if (match(tok))
return Action::Match;
if (Token::simpleMatch(tok, ".") && analyzeLifetime(tok->astOperand1()) != Action::None)
return Action::Read;
if (astIsRHS(tok) && Token::simpleMatch(tok->astParent(), "."))
return analyzeLifetime(tok->astParent());
return Action::None;
}
struct ConditionState {
bool dependent = true;
bool unknown = true;
bool isUnknownDependent() const {
return unknown && dependent;
}
};
std::unordered_map<nonneg int, const Token*> getSymbols(const Token* tok) const
{
std::unordered_map<nonneg int, const Token*> result;
if (!tok)
return result;
for (const ValueFlow::Value& v : tok->values()) {
if (!v.isSymbolicValue())
continue;
if (v.isImpossible())
continue;
if (!v.tokvalue)
continue;
if (v.tokvalue->exprId() == 0)
continue;
if (match(v.tokvalue))
continue;
result[v.tokvalue->exprId()] = v.tokvalue;
}
return result;
}
ConditionState analyzeCondition(const Token* tok, int depth = 20) const
{
ConditionState result;
if (!tok)
return result;
if (depth < 0)
return result;
depth--;
if (analyze(tok, Direction::Forward).isRead()) {
result.dependent = true;
result.unknown = false;
return result;
}
if (tok->hasKnownIntValue() || tok->isLiteral()) {
result.dependent = false;
result.unknown = false;
return result;
}
if (Token::Match(tok, "%cop%")) {
if (isLikelyStream(isCPP(), tok->astOperand1())) {
result.dependent = false;
return result;
}
ConditionState lhs = analyzeCondition(tok->astOperand1(), depth - 1);
if (lhs.isUnknownDependent())
return lhs;
ConditionState rhs = analyzeCondition(tok->astOperand2(), depth - 1);
if (rhs.isUnknownDependent())
return rhs;
if (Token::Match(tok, "%comp%"))
result.dependent = lhs.dependent && rhs.dependent;
else
result.dependent = lhs.dependent || rhs.dependent;
result.unknown = lhs.unknown || rhs.unknown;
return result;
}
if (Token::Match(tok->previous(), "%name% (")) {
std::vector<const Token*> args = getArguments(tok->previous());
if (Token::Match(tok->tokAt(-2), ". %name% (")) {
args.push_back(tok->tokAt(-2)->astOperand1());
}
result.dependent = std::any_of(args.cbegin(), args.cend(), [&](const Token* arg) {
ConditionState cs = analyzeCondition(arg, depth - 1);
return cs.dependent;
});
if (result.dependent) {
// Check if we can evaluate the function
if (!evaluate(Evaluate::Integral, tok).empty())
result.unknown = false;
}
return result;
}
std::unordered_map<nonneg int, const Token*> symbols = getSymbols(tok);
result.dependent = false;
for (auto&& p : symbols) {
const Token* arg = p.second;
ConditionState cs = analyzeCondition(arg, depth - 1);
result.dependent = cs.dependent;
if (result.dependent)
break;
}
if (result.dependent) {
// Check if we can evaluate the token
if (!evaluate(Evaluate::Integral, tok).empty())
result.unknown = false;
}
return result;
}
virtual Action isModified(const Token* tok) const {
const Action read = Action::Read;
const ValueFlow::Value* value = getValue(tok);
if (value) {
// Moving a moved value won't change the moved value
if (value->isMovedValue() && isMoveOrForward(tok) != ValueFlow::Value::MoveKind::NonMovedVariable)
return read;
// Inserting elements to container won't change the lifetime
if (astIsContainer(tok) && value->isLifetimeValue() &&
contains({Library::Container::Action::PUSH,
Library::Container::Action::INSERT,
Library::Container::Action::CHANGE_INTERNAL},
astContainerAction(tok)))
return 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;
// Check if its assigned to the same value
if (value && !value->isImpossible() && Token::simpleMatch(tok->astParent(), "=") && astIsLHS(tok) &&
astIsIntegral(tok->astParent()->astOperand2(), false)) {
std::vector<MathLib::bigint> result = evaluateInt(tok->astParent()->astOperand2());
if (!result.empty() && value->equalTo(result.front()))
return Action::Idempotent;
}
return Action::Invalid;
}
return read;
}
virtual Action isAliasModified(const Token* tok, int indirect = -1) const {
// Lambda function call
if (Token::Match(tok, "%var% ("))
// TODO: Check if modified in the lambda function
return Action::Invalid;
if (indirect == -1) {
indirect = 0;
if (const ValueType* vt = tok->valueType()) {
indirect = vt->pointer;
if (vt->type == ValueType::ITERATOR)
++indirect;
}
}
for (int i = 0; i <= indirect; ++i)
if (isVariableChanged(tok, i, getSettings(), isCPP()))
return Action::Invalid;
return Action::None;
}
virtual Action isThisModified(const Token* tok) const {
if (isThisChanged(tok, 0, getSettings(), isCPP()))
return Action::Invalid;
return Action::None;
}
Action isGlobalModified(const Token* tok) const
{
if (tok->function()) {
if (!tok->function()->isConstexpr() && !isConstFunctionCall(tok, getSettings()->library))
return Action::Invalid;
} else if (getSettings()->library.getFunction(tok)) {
// Assume library function doesn't modify user-global variables
return Action::None;
} else if (Token::simpleMatch(tok->astParent(), ".") && astIsContainer(tok->astParent()->astOperand1())) {
// Assume container member function doesn't modify user-global variables
return Action::None;
} else if (tok->tokType() == Token::eType && astIsPrimitive(tok->next())) {
// Function cast does not modify global variables
return Action::None;
} else if (!tok->isKeyword() && Token::Match(tok, "%name% (")) {
return Action::Invalid;
}
return Action::None;
}
static const std::string& getAssign(const Token* tok, Direction d)
{
if (d == Direction::Forward)
return tok->str();
return invertAssign(tok->str());
}
virtual Action isWritable(const Token* tok, Direction d) const {
const ValueFlow::Value* value = getValue(tok);
if (!value)
return Action::None;
if (!(value->isIntValue() || value->isFloatValue() || value->isSymbolicValue() || value->isLifetimeValue()))
return Action::None;
const Token* parent = tok->astParent();
// Only if its invertible
if (value->isImpossible() && !Token::Match(parent, "+=|-=|*=|++|--"))
return Action::None;
if (value->isLifetimeValue()) {
if (value->lifetimeKind != ValueFlow::Value::LifetimeKind::Iterator)
return Action::None;
if (!Token::Match(parent, "++|--|+="))
return Action::None;
return Action::Read | Action::Write;
}
if (parent && parent->isAssignmentOp() && astIsLHS(tok)) {
const Token* rhs = parent->astOperand2();
std::vector<MathLib::bigint> result = evaluateInt(rhs);
if (!result.empty()) {
ValueFlow::Value rhsValue{result.front()};
Action a;
if (!evalAssignment(*value, getAssign(parent, d), rhsValue))
a = Action::Invalid;
else
a = Action::Write;
if (parent->str() != "=") {
a |= Action::Read | Action::Incremental;
} else {
if (!value->isImpossible() && value->equalValue(rhsValue))
a = Action::Idempotent;
if (tok->exprId() != 0 &&
findAstNode(rhs, [&](const Token* child) {
return tok->exprId() == child->exprId();
}))
a |= Action::Incremental;
}
return a;
}
}
// increment/decrement
if (Token::Match(tok->astParent(), "++|--")) {
return Action::Read | Action::Write | Action::Incremental;
}
return Action::None;
}
virtual void writeValue(ValueFlow::Value* value, const Token* tok, Direction d) const {
if (!value)
return;
if (!tok->astParent())
return;
// Lifetime value doesn't change
if (value->isLifetimeValue())
return;
if (tok->astParent()->isAssignmentOp()) {
const Token* rhs = tok->astParent()->astOperand2();
std::vector<MathLib::bigint> result = evaluateInt(rhs);
assert(!result.empty());
ValueFlow::Value rhsValue{result.front()};
if (evalAssignment(*value, getAssign(tok->astParent(), d), rhsValue)) {
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, std::move(info));
} else {
assert(false && "Writable value cannot be evaluated");
// TODO: Don't set to zero
value->intvalue = 0;
}
} else if (tok->astParent()->tokType() == Token::eIncDecOp) {
bool inc = tok->astParent()->str() == "++";
const std::string opName(inc ? "incremented" : "decremented");
if (d == Direction::Reverse)
inc = !inc;
value->intvalue += (inc ? 1 : -1);
value->errorPath.emplace_back(tok, tok->str() + " is " + opName + "', new value is " + value->infoString());
}
}
virtual bool useSymbolicValues() const {
return true;
}
const Token* findMatch(const Token* tok) const
{
return findAstNode(tok, [&](const Token* child) {
return match(child);
});
}
bool isSameSymbolicValue(const Token* tok, ValueFlow::Value* value = nullptr) const
{
if (!useSymbolicValues())
return false;
if (Token::Match(tok, "%assign%"))
return false;
const ValueFlow::Value* currValue = getValue(tok);
if (!currValue)
return false;
// If the same symbolic value is already there then skip
if (currValue->isSymbolicValue() &&
std::any_of(tok->values().cbegin(), tok->values().cend(), [&](const ValueFlow::Value& v) {
return v.isSymbolicValue() && currValue->equalValue(v);
}))
return false;
const bool isPoint = currValue->bound == ValueFlow::Value::Bound::Point && currValue->isIntValue();
const bool exact = !currValue->isIntValue() || currValue->isImpossible();
for (const ValueFlow::Value& v : tok->values()) {
if (!v.isSymbolicValue())
continue;
if (currValue->equalValue(v))
continue;
const bool toImpossible = v.isImpossible() && currValue->isKnown();
if (!v.isKnown() && !toImpossible)
continue;
if (exact && v.intvalue != 0 && !isPoint)
continue;
std::vector<MathLib::bigint> r;
ValueFlow::Value::Bound bound = currValue->bound;
if (match(v.tokvalue)) {
r = {currValue->intvalue};
} else if (!exact && findMatch(v.tokvalue)) {
r = evaluate(Evaluate::Integral, v.tokvalue, tok);
if (bound == ValueFlow::Value::Bound::Point)
bound = v.bound;
}
if (!r.empty()) {
if (value) {
value->errorPath.insert(value->errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend());
value->intvalue = r.front() + v.intvalue;
if (toImpossible)
value->setImpossible();
value->bound = bound;
}
return true;
}
}
return false;
}
Action analyzeMatch(const Token* tok, Direction d) const {
const Token* parent = tok->astParent();
if (d == Direction::Reverse && isGlobal() && !dependsOnThis() && Token::Match(parent, ". %name% (")) {
Action a = isGlobalModified(parent->next());
if (a != Action::None)
return a;
}
if ((astIsPointer(tok) || astIsSmartPointer(tok)) &&
(Token::Match(parent, "*|[") || (parent && parent->originalName() == "->")) && getIndirect(tok) <= 0)
return Action::Read;
Action w = isWritable(tok, d);
if (w != Action::None)
return w;
// Check for modifications by function calls
return isModified(tok);
}
Action analyzeToken(const Token* ref, const Token* tok, Direction d, bool inconclusiveRef) const {
if (!ref)
return Action::None;
// If its an inconclusiveRef then ref != tok
assert(!inconclusiveRef || ref != tok);
bool inconclusive = false;
if (match(ref)) {
if (inconclusiveRef) {
Action a = isModified(tok);
if (a.isModified() || a.isInconclusive())
return Action::Inconclusive;
} else {
return analyzeMatch(tok, d) | Action::Match;
}
} else if (ref->isUnaryOp("*") && !match(ref->astOperand1())) {
const Token* lifeTok = nullptr;
for (const ValueFlow::Value& v:ref->astOperand1()->values()) {
if (!v.isLocalLifetimeValue())
continue;
if (lifeTok)
return Action::None;
lifeTok = v.tokvalue;
}
if (!lifeTok)
return Action::None;
Action la = analyzeLifetime(lifeTok);
if (la.matches()) {
Action a = Action::Read;
if (isModified(tok).isModified())
a = Action::Invalid;
if (Token::Match(tok->astParent(), "%assign%") && astIsLHS(tok))
a |= Action::Invalid;
if (inconclusiveRef && a.isModified())
return Action::Inconclusive;
return a;
}
if (la.isRead()) {
return isAliasModified(tok);
}
return Action::None;
} else if (isAlias(ref, inconclusive)) {
inconclusive |= inconclusiveRef;
Action a = isAliasModified(tok);
if (inconclusive && a.isModified())
return Action::Inconclusive;
return a;
}
if (isSameSymbolicValue(ref))
return Action::Read | Action::SymbolicMatch;
return Action::None;
}
Action analyze(const Token* tok, Direction d) const override {
if (invalid())
return Action::Invalid;
// Follow references
auto refs = followAllReferences(tok);
const bool inconclusiveRefs = refs.size() != 1;
if (std::none_of(refs.cbegin(), refs.cend(), [&](const ReferenceToken& ref) {
return tok == ref.token;
}))
refs.emplace_back(ReferenceToken{tok, {}});
for (const ReferenceToken& ref:refs) {
Action a = analyzeToken(ref.token, tok, d, inconclusiveRefs && ref.token != tok);
if (internalMatch(ref.token))
a |= Action::Internal;
if (a != Action::None)
return a;
}
if (dependsOnThis() && exprDependsOnThis(tok, !isVariable()))
return isThisModified(tok);
// bailout: global non-const variables
if (isGlobal() && !dependsOnThis() && Token::Match(tok, "%name% (") &&
!Token::simpleMatch(tok->linkAt(1), ") {")) {
return isGlobalModified(tok);
}
return Action::None;
}
template<class F>
std::vector<MathLib::bigint> evaluateInt(const Token* tok, F getProgramMemory) const
{
if (tok->hasKnownIntValue())
return {static_cast<int>(tok->values().front().intvalue)};
std::vector<MathLib::bigint> result;
ProgramMemory pm = getProgramMemory();
if (Token::Match(tok, "&&|%oror%")) {
if (conditionIsTrue(tok, pm, getSettings()))
result.push_back(1);
if (conditionIsFalse(tok, pm, getSettings()))
result.push_back(0);
} else {
MathLib::bigint out = 0;
bool error = false;
execute(tok, pm, &out, &error, getSettings());
if (!error)
result.push_back(out);
}
return result;
}
std::vector<MathLib::bigint> evaluateInt(const Token* tok) const
{
return evaluateInt(tok, [&] {
return ProgramMemory{getProgramState()};
});
}
std::vector<MathLib::bigint> evaluate(Evaluate e, const Token* tok, const Token* ctx = nullptr) const override
{
if (e == Evaluate::Integral) {
return evaluateInt(tok, [&] {
return pms.get(tok, ctx, getProgramState());
});
}
if (e == Evaluate::ContainerEmpty) {
const ValueFlow::Value* value = ValueFlow::findValue(tok->values(), nullptr, [](const ValueFlow::Value& v) {
return v.isKnown() && v.isContainerSizeValue();
});
if (value)
return {value->intvalue == 0};
ProgramMemory pm = pms.get(tok, ctx, getProgramState());
MathLib::bigint out = 0;
if (pm.getContainerEmptyValue(tok->exprId(), out))
return {static_cast<int>(out)};
return {};
}
return {};
}
void assume(const Token* tok, bool state, unsigned int flags) override {
// Update program state
pms.removeModifiedVars(tok);
pms.addState(tok, getProgramState());
pms.assume(tok, state, flags & Assume::ContainerEmpty);
bool isCondBlock = false;
const Token* parent = tok->astParent();
if (parent) {
isCondBlock = Token::Match(parent->previous(), "if|while (");
}
if (isCondBlock) {
const Token* startBlock = parent->link()->next();
if (Token::simpleMatch(startBlock, ";") && Token::simpleMatch(parent->tokAt(-2), "} while ("))
startBlock = parent->linkAt(-2);
const Token* endBlock = startBlock->link();
if (state) {
pms.removeModifiedVars(endBlock);
pms.addState(endBlock->previous(), getProgramState());
} else {
if (Token::simpleMatch(endBlock, "} else {"))
pms.addState(endBlock->linkAt(2)->previous(), getProgramState());
}
}
if (!(flags & Assume::Quiet)) {
if (flags & Assume::ContainerEmpty) {
std::string s = state ? "empty" : "not empty";
addErrorPath(tok, "Assuming container is " + s);
} else {
std::string s = bool_to_string(state);
addErrorPath(tok, "Assuming condition is " + s);
}
}
if (!(flags & Assume::Absolute))
makeConditional();
}
virtual void internalUpdate(Token* /*tok*/, const ValueFlow::Value& /*v*/, Direction /*d*/)
{
assert(false && "Internal update unimplemented.");
}
void update(Token* tok, Action a, Direction d) override {
ValueFlow::Value* value = getValue(tok);
if (!value)
return;
ValueFlow::Value localValue;
if (a.isSymbolicMatch()) {
// Make a copy of the value to modify it
localValue = *value;
value = &localValue;
isSameSymbolicValue(tok, &localValue);
}
if (a.isInternal())
internalUpdate(tok, *value, d);
// Read first when moving forward
if (d == Direction::Forward && a.isRead())
setTokenValue(tok, *value, getSettings());
if (a.isInconclusive())
lowerToInconclusive();
if (a.isWrite() && tok->astParent()) {
writeValue(value, tok, d);
}
// Read last when moving in reverse
if (d == Direction::Reverse && a.isRead())
setTokenValue(tok, *value, getSettings());
}
ValuePtr<Analyzer> reanalyze(Token* /*tok*/, const std::string& /*msg*/) const override {
return {};
}
};
struct SingleValueFlowAnalyzer : ValueFlowAnalyzer {
std::unordered_map<nonneg int, const Variable*> varids;
std::unordered_map<nonneg int, const Variable*> aliases;
ValueFlow::Value value;
SingleValueFlowAnalyzer(ValueFlow::Value v, const TokenList& t, const Settings* s) : ValueFlowAnalyzer(t, s), value(std::move(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;
}
const ValueFlow::Value* getValue(const Token* /*tok*/) const override {
return &value;
}
ValueFlow::Value* getValue(const Token* /*tok*/) override {
return &value;
}
void makeConditional() override {
value.conditional = true;
}
bool useSymbolicValues() const override
{
if (value.isUninitValue())
return false;
if (value.isLifetimeValue())
return false;
return true;
}
void addErrorPath(const Token* tok, const std::string& s) override {
value.errorPath.emplace_back(tok, s);
}
bool isAlias(const Token* tok, bool& inconclusive) 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 const varid = p.first;
const Variable* var = p.second;
if (tok->varId() == varid)
return true;
if (isAliasOf(var, tok, varid, MakeSingleRange(value), &inconclusive))
return true;
}
}
return false;
}
bool isGlobal() const override {
const auto& vars = getVars();
return std::any_of(vars.cbegin(), vars.cend(), [] (const std::pair<nonneg int, const Variable*>& p) {
const Variable* var = p.second;
return !var->isLocal() && !var->isArgument() && !var->isConst();
});
}
bool lowerToPossible() override {
if (value.isImpossible())
return false;
value.changeKnownToPossible();
return true;
}
bool lowerToInconclusive() override {
if (value.isImpossible())
return false;
value.setInconclusive();
return true;
}
bool isConditional() const override {
if (value.conditional)
return true;
if (value.condition)
return !value.isKnown() && !value.isImpossible();
return false;
}
bool stopOnCondition(const Token* condTok) const override
{
if (value.isNonValue())
return false;
if (value.isImpossible())
return false;
if (isConditional() && !value.isKnown() && !value.isImpossible())
return true;
if (value.isSymbolicValue())
return false;
ConditionState cs = analyzeCondition(condTok);
return cs.isUnknownDependent();
}
bool updateScope(const Token* endBlock, bool /*modified*/) const override {
const Scope* scope = endBlock->scope();
if (!scope)
return false;
if (scope->type == Scope::eLambda)
return value.isLifetimeValue();
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().cbegin(), getVars().cend(), std::inserter(varids2, varids2.begin()), SelectMapKeys{});
return bifurcate(condTok, varids2, getSettings());
}
return false;
}
ValuePtr<Analyzer> reanalyze(Token* tok, const std::string& msg) const override {
ValueFlow::Value newValue = value;
newValue.errorPath.emplace_back(tok, msg);
return makeAnalyzer(tok, std::move(newValue), tokenlist, settings);
}
};
struct ExpressionAnalyzer : SingleValueFlowAnalyzer {
const Token* expr;
bool local = true;
bool unknown{};
bool dependOnThis{};
bool uniqueExprId{};
ExpressionAnalyzer(const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s)
: SingleValueFlowAnalyzer(std::move(val), t, s),
expr(e)
{
assert(e && e->exprId() != 0 && "Not a valid expression");
dependOnThis = exprDependsOnThis(expr);
setupExprVarIds(expr);
if (value.isSymbolicValue()) {
dependOnThis |= exprDependsOnThis(value.tokvalue);
setupExprVarIds(value.tokvalue);
}
uniqueExprId =
expr->isUniqueExprId() && (Token::Match(expr, "%cop%") || !isVariableChanged(expr, 0, s, t.isCPP()));
}
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(const Token* start, int depth = 0) {
constexpr int maxDepth = 4;
if (depth > maxDepth)
return;
visitAstNodes(start, [&](const Token* tok) {
const bool top = depth == 0 && tok == start;
const bool ispointer = astIsPointer(tok) || astIsSmartPointer(tok) || astIsIterator(tok);
if (!top || !ispointer || value.indirect != 0) {
for (const ValueFlow::Value& v : tok->values()) {
if (!(v.isLocalLifetimeValue() || (ispointer && v.isSymbolicValue() && v.isKnown())))
continue;
if (!v.tokvalue)
continue;
if (v.tokvalue == tok)
continue;
setupExprVarIds(v.tokvalue, depth + 1);
}
}
if (depth == 0 && tok->isIncompleteVar()) {
// TODO: Treat incomplete var as global, but we need to update
// the alias variables to just expr ids instead of requiring
// 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 skipUniqueExprIds() const {
return true;
}
bool invalid() const override {
if (skipUniqueExprIds() && uniqueExprId)
return true;
return unknown;
}
ProgramState getProgramState() const override {
ProgramState ps;
ps[expr] = value;
return ps;
}
bool match(const Token* tok) const override {
return tok->exprId() == expr->exprId();
}
bool dependsOnThis() const override {
return dependOnThis;
}
bool isGlobal() const override {
return !local;
}
bool isVariable() const override {
return expr->varId() > 0;
}
Action isAliasModified(const Token* tok, int indirect) const override {
if (value.isSymbolicValue() && tok->exprId() == value.tokvalue->exprId())
indirect = 0;
return SingleValueFlowAnalyzer::isAliasModified(tok, indirect);
}
};
struct SameExpressionAnalyzer : ExpressionAnalyzer {
SameExpressionAnalyzer(const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s)
: ExpressionAnalyzer(e, std::move(val), t, s)
{}
bool skipUniqueExprIds() const override {
return false;
}
bool match(const Token* tok) const override
{
return isSameExpression(isCPP(), true, expr, tok, getSettings()->library, true, true);
}
};
struct OppositeExpressionAnalyzer : ExpressionAnalyzer {
bool isNot{};
OppositeExpressionAnalyzer(bool pIsNot, const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s)
: ExpressionAnalyzer(e, std::move(val), t, s), isNot(pIsNot)
{}
bool skipUniqueExprIds() const override {
return false;
}
bool match(const Token* tok) const override {
return isOppositeCond(isNot, isCPP(), expr, tok, getSettings()->library, true, true);
}
};
struct SubExpressionAnalyzer : ExpressionAnalyzer {
using PartialReadContainer = std::vector<std::pair<Token *, ValueFlow::Value>>;
// A shared_ptr is used so partial reads can be captured even after forking
std::shared_ptr<PartialReadContainer> partialReads;
SubExpressionAnalyzer(const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s)
: ExpressionAnalyzer(e, std::move(val), t, s), partialReads(std::make_shared<PartialReadContainer>())
{}
virtual bool submatch(const Token* tok, bool exact = true) const = 0;
bool isAlias(const Token* tok, bool& inconclusive) const override
{
if (tok->exprId() == expr->exprId() && tok->astParent() && submatch(tok->astParent(), false))
return false;
return ExpressionAnalyzer::isAlias(tok, inconclusive);
}
bool match(const Token* tok) const override
{
return tok->astOperand1() && tok->astOperand1()->exprId() == expr->exprId() && submatch(tok);
}
bool internalMatch(const Token* tok) const override
{
return tok->exprId() == expr->exprId() && !(astIsLHS(tok) && submatch(tok->astParent(), false));
}
void internalUpdate(Token* tok, const ValueFlow::Value& v, Direction /*d*/) override
{
partialReads->emplace_back(tok, v);
}
// No reanalysis for subexpression
ValuePtr<Analyzer> reanalyze(Token* /*tok*/, const std::string& /*msg*/) const override {
return {};
}
};
struct MemberExpressionAnalyzer : SubExpressionAnalyzer {
std::string varname;
MemberExpressionAnalyzer(std::string varname, const Token* e, ValueFlow::Value val, const TokenList& t, const Settings* s)
: SubExpressionAnalyzer(e, std::move(val), t, s), varname(std::move(varname))
{}
bool submatch(const Token* tok, bool exact) const override
{
if (!Token::Match(tok, ". %var%"))
return false;
if (!exact)
return true;
return tok->next()->str() == varname;
}
};
enum class LifetimeCapture { Undefined, ByValue, ByReference };
static 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 if (Token::simpleMatch(tok, "=") && astIsPointer(tok->astOperand2()))
result = "pointer";
else
result = "object";
break;
}
return result;
}
std::string ValueFlow::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;
const bool classVar = tokvar ? (!tokvar->isLocal() && !tokvar->isArgument() && !tokvar->isGlobal()) : false;
std::string type = lifetimeType(tok, val);
std::string msg = type;
if (vartok) {
if (!classVar)
errorPath.emplace_back(vartok, "Variable created here.");
const Variable * var = vartok->variable();
if (var) {
std::string submessage;
switch (val->lifetimeKind) {
case ValueFlow::Value::LifetimeKind::SubObject:
case ValueFlow::Value::LifetimeKind::Object:
case ValueFlow::Value::LifetimeKind::Address:
if (type == "pointer")
submessage = " to local variable";
else
submessage = " that points to local variable";
break;
case ValueFlow::Value::LifetimeKind::Lambda:
submessage = " that captures local variable";
break;
case ValueFlow::Value::LifetimeKind::Iterator:
submessage = " to local container";
break;
}
if (classVar)
submessage.replace(submessage.find("local"), 5, "member");
msg += submessage + " '" + var->name() + "'";
}
}
return msg;
}
std::vector<ValueFlow::Value> ValueFlow::getLifetimeObjValues(const Token* tok, bool inconclusive, MathLib::bigint path)
{
std::vector<ValueFlow::Value> result;
auto pred = [&](const ValueFlow::Value& v) {
if (!v.isLocalLifetimeValue() && !(path != 0 && v.isSubFunctionLifetimeValue()))
return false;
if (!inconclusive && v.isInconclusive())
return false;
if (!v.tokvalue)
return false;
if (path >= 0 && v.path != 0 && v.path != path)
return false;
return true;
};
std::copy_if(tok->values().cbegin(), tok->values().cend(), std::back_inserter(result), pred);
return result;
}
static bool hasUniqueOwnership(const Token* tok)
{
if (!tok)
return false;
const Variable* var = tok->variable();
if (var && var->isArray() && !var->isArgument())
return true;
if (astIsPointer(tok))
return false;
if (astIsUniqueSmartPointer(tok))
return true;
if (astIsContainerOwned(tok))
return true;
return false;
}
// Check if dereferencing an object that doesn't have unique ownership
static bool derefShared(const Token* tok)
{
if (!tok)
return false;
if (!tok->isUnaryOp("*") && tok->str() != "[" && tok->str() != ".")
return false;
if (tok->str() == "." && tok->originalName() != "->")
return false;
const Token* ptrTok = tok->astOperand1();
return !hasUniqueOwnership(ptrTok);
}
ValueFlow::Value ValueFlow::getLifetimeObjValue(const Token *tok, bool inconclusive)
{
std::vector<ValueFlow::Value> values = ValueFlow::getLifetimeObjValues(tok, inconclusive);
// There should only be one lifetime
if (values.size() != 1)
return ValueFlow::Value{};
return values.front();
}
template<class Predicate>
static std::vector<ValueFlow::LifetimeToken> getLifetimeTokens(const Token* tok,
bool escape,
ValueFlow::Value::ErrorPath errorPath,
Predicate pred,
int depth = 20)
{
if (!tok)
return std::vector<ValueFlow::LifetimeToken> {};
if (Token::simpleMatch(tok, "..."))
return std::vector<ValueFlow::LifetimeToken>{};
const Variable *var = tok->variable();
if (pred(tok))
return {{tok, std::move(errorPath)}};
if (depth < 0)
return {{tok, std::move(errorPath)}};
if (var && var->declarationId() == tok->varId()) {
if (var->isReference() || var->isRValueReference()) {
const Token * const varDeclEndToken = var->declEndToken();
if (!varDeclEndToken)
return {{tok, true, std::move(errorPath)}};
if (var->isArgument()) {
errorPath.emplace_back(varDeclEndToken, "Passed to reference.");
return {{tok, true, std::move(errorPath)}};
}
if (Token::Match(varDeclEndToken, "=|{")) {
errorPath.emplace_back(varDeclEndToken, "Assigned to reference.");
const Token *vartok = varDeclEndToken->astOperand2();
const bool temporary = isTemporary(true, vartok, nullptr, true);
const bool nonlocal = var->isStatic() || var->isGlobal();
if (vartok == tok || (nonlocal && temporary) ||
(!escape && (var->isConst() || var->isRValueReference()) && temporary))
return {{tok, true, std::move(errorPath)}};
if (vartok)
return getLifetimeTokens(vartok, escape, std::move(errorPath), pred, 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 (astIsContainer(contok))
return getLifetimeTokens(contok, escape, std::move(errorPath), pred, depth - 1);
return std::vector<ValueFlow::LifetimeToken>{};
} else {
return std::vector<ValueFlow::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<ValueFlow::LifetimeToken> result;
std::vector<const Token*> returns = Function::findReturns(f);
for (const Token* returnTok : returns) {
if (returnTok == tok)
continue;
for (ValueFlow::LifetimeToken& lt : getLifetimeTokens(returnTok, escape, errorPath, pred, depth - returns.size())) {
const Token* argvarTok = lt.token;
const Variable* argvar = argvarTok->variable();
if (!argvar)
continue;
const Token* argTok = nullptr;
if (argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) {
const int n = getArgumentPos(argvar, f);
if (n < 0)
return std::vector<ValueFlow::LifetimeToken> {};
std::vector<const Token*> args = getArguments(tok->previous());
// TODO: Track lifetimes of default parameters
if (n >= args.size())
return std::vector<ValueFlow::LifetimeToken> {};
argTok = args[n];
lt.errorPath.emplace_back(returnTok, "Return reference.");
lt.errorPath.emplace_back(tok->previous(), "Called function passing '" + argTok->expressionString() + "'.");
} else if (Token::Match(tok->tokAt(-2), ". %name% (") && !derefShared(tok->tokAt(-2)) &&
exprDependsOnThis(argvarTok)) {
argTok = tok->tokAt(-2)->astOperand1();
lt.errorPath.emplace_back(returnTok, "Return reference that depends on 'this'.");
lt.errorPath.emplace_back(tok->previous(),
"Calling member function on '" + argTok->expressionString() + "'.");
}
if (argTok) {
std::vector<ValueFlow::LifetimeToken> arglts = ValueFlow::LifetimeToken::setInconclusive(
getLifetimeTokens(argTok, escape, std::move(lt.errorPath), pred, depth - returns.size()),
returns.size() > 1);
result.insert(result.end(), arglts.cbegin(), arglts.cend());
}
}
}
return result;
}
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());
const 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 ValueFlow::LifetimeToken::setAddressOf(
getLifetimeTokens(tok->tokAt(-2)->astOperand1(), escape, std::move(errorPath), pred, depth - 1),
false);
}
}
} else if (Token::Match(tok, ".|::|[") || tok->isUnaryOp("*")) {
const Token *vartok = tok;
while (vartok) {
if (vartok->str() == "[" || vartok->originalName() == "->" || vartok->isUnaryOp("*"))
vartok = vartok->astOperand1();
else if (vartok->str() == "." || vartok->str() == "::")
vartok = vartok->astOperand2();
else
break;
}
if (!vartok)
return {{tok, std::move(errorPath)}};
if (derefShared(vartok->astParent())) {
for (const ValueFlow::Value &v : vartok->values()) {
if (!v.isLocalLifetimeValue())
continue;
if (v.tokvalue == tok)
continue;
errorPath.insert(errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend());
return getLifetimeTokens(v.tokvalue, escape, std::move(errorPath), pred, depth - 1);
}
} else {
return ValueFlow::LifetimeToken::setAddressOf(getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1),
!(astIsContainer(vartok) && Token::simpleMatch(vartok->astParent(), "[")));
}
} else if (Token::simpleMatch(tok, "{") && getArgumentStart(tok) &&
!Token::simpleMatch(getArgumentStart(tok), ",") && getArgumentStart(tok)->valueType()) {
const Token* vartok = getArgumentStart(tok);
auto vts = getParentValueTypes(tok);
auto it = std::find_if(vts.cbegin(), vts.cend(), [&](const ValueType& vt) {
return vt.isTypeEqual(vartok->valueType());
});
if (it != vts.end())
return getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1);
}
return {{tok, std::move(errorPath)}};
}
std::vector<ValueFlow::LifetimeToken> ValueFlow::getLifetimeTokens(const Token* tok, bool escape, ValueFlow::Value::ErrorPath errorPath)
{
return getLifetimeTokens(tok, escape, std::move(errorPath), [](const Token*) {
return false;
});
}
bool ValueFlow::hasLifetimeToken(const Token* tok, const Token* lifetime)
{
bool result = false;
getLifetimeTokens(tok, false, ValueFlow::Value::ErrorPath{}, [&](const Token* tok2) {
result = tok2->exprId() == lifetime->exprId();
return result;
});
return result;
}
static const Token* getLifetimeToken(const Token* tok, ValueFlow::Value::ErrorPath& errorPath, bool* addressOf = nullptr)
{
std::vector<ValueFlow::LifetimeToken> lts = ValueFlow::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.cbegin(), lts.front().errorPath.cend());
return lts.front().token;
}
const Variable* ValueFlow::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* ValueFlow::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* vtParent)
{
if (vtParent->container)
return !vtParent->container->view;
return vtParent->type == ValueType::CONTAINER;
}
static bool isLifetimeOwned(const ValueType *vt, const ValueType *vtParent)
{
if (!vtParent)
return false;
if (isLifetimeOwned(vtParent))
return true;
if (!vt)
return false;
// If converted from iterator to pointer then the iterator is most likely a pointer
if (vtParent->pointer == 1 && vt->pointer == 0 && vt->type == ValueType::ITERATOR)
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 (isLifetimeOwned(vtParent))
return true;
}
}
return false;
}
static bool isLifetimeBorrowed(const ValueType *vt, const ValueType *vtParent)
{
if (!vtParent)
return false;
if (!vt)
return false;
if (vt->pointer > 0 && vt->pointer == vtParent->pointer)
return true;
if (vtParent->container && vtParent->container->view)
return true;
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;
}
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);
}
static bool isDifferentType(const Token* src, const Token* dst)
{
const Type* t = Token::typeOf(src);
const Type* parentT = Token::typeOf(dst);
if (t && parentT) {
if (t->classDef && parentT->classDef && t->classDef != parentT->classDef)
return true;
} else {
std::pair<const Token*, const Token*> decl = Token::typeDecl(src);
std::pair<const Token*, const Token*> parentdecl = Token::typeDecl(dst);
if (isNotEqual(decl, parentdecl))
return true;
if (isNotEqual(decl, dst->valueType()))
return true;
if (isNotEqual(parentdecl, src->valueType()))
return true;
}
return false;
}
bool ValueFlow::isLifetimeBorrowed(const Token *tok, const Settings *settings)
{
if (!tok)
return true;
if (tok->str() == ",")
return true;
if (!tok->astParent())
return true;
const Token* parent = nullptr;
const ValueType* vt = tok->valueType();
std::vector<ValueType> vtParents = getParentValueTypes(tok, settings, &parent);
for (const ValueType& vtParent : vtParents) {
if (isLifetimeBorrowed(vt, &vtParent))
return true;
if (isLifetimeOwned(vt, &vtParent))
return false;
}
if (parent) {
if (isDifferentType(tok, parent))
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 bool isRangeForScope(const Scope* scope)
{
if (!scope)
return false;
if (scope->type != Scope::eFor)
return false;
if (!scope->bodyStart)
return false;
if (!Token::simpleMatch(scope->bodyStart->previous(), ") {"))
return false;
return Token::simpleMatch(scope->bodyStart->linkAt(-1)->astOperand2(), ":");
}
static const Token* getEndOfVarScope(const Variable* var)
{
if (!var)
return nullptr;
const Scope* innerScope = var->scope();
const Scope* outerScope = innerScope;
if (var->typeStartToken() && var->typeStartToken()->scope())
outerScope = var->typeStartToken()->scope();
if (!innerScope && outerScope)
innerScope = outerScope;
if (!innerScope || !outerScope)
return nullptr;
if (!innerScope->isExecutable())
return nullptr;
// If the variable is defined in a for/while initializer then we want to
// pick one token after the end so forward analysis can analyze the exit
// conditions
if (innerScope != outerScope && outerScope->isExecutable() && innerScope->isLoopScope() &&
!isRangeForScope(innerScope))
return innerScope->bodyEnd->next();
return innerScope->bodyEnd;
}
const Token* ValueFlow::getEndOfExprScope(const Token* tok, const Scope* defaultScope, bool smallest)
{
const Token* end = nullptr;
bool local = false;
visitAstNodes(tok, [&](const Token* child) {
if (const Variable* var = child->variable()) {
local |= var->isLocal();
if (var->isLocal() || var->isArgument()) {
const Token* varEnd = getEndOfVarScope(var);
if (!end || (smallest ? precedes(varEnd, end) : succeeds(varEnd, end)))
end = varEnd;
const Token* top = var->nameToken()->astTop();
if (top && Token::simpleMatch(top->tokAt(-1), "if (")) { // variable declared in if (...)
const Token* elseTok = top->link()->linkAt(1);
if (Token::simpleMatch(elseTok, "} else {") && tok->scope()->isNestedIn(elseTok->tokAt(2)->scope()))
end = tok->scope()->bodyEnd;
}
}
}
return ChildrenToVisit::op1_and_op2;
});
if (!end && defaultScope)
end = defaultScope->bodyEnd;
if (!end) {
const Scope* scope = tok->scope();
if (scope)
end = scope->bodyEnd;
// If there is no local variables then pick the function scope
if (!local) {
while (scope && scope->isLocal())
scope = scope->nestedIn;
if (scope && scope->isExecutable())
end = scope->bodyEnd;
}
}
return end;
}
static void valueFlowForwardLifetime(Token * tok, TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
// Forward lifetimes to constructed variable
if (Token::Match(tok->previous(), "%var% {|(") && isVariableDecl(tok->previous())) {
std::list<ValueFlow::Value> values = tok->values();
values.remove_if(&isNotLifetimeValue);
valueFlowForward(nextAfterAstRightmostLeaf(tok), ValueFlow::getEndOfExprScope(tok), tok->previous(), values, tokenlist, settings);
return;
}
Token *parent = tok->astParent();
while (parent && 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 (!ValueFlow::isLifetimeBorrowed(parent->astOperand2(), settings))
return;
const Token* expr = getLHSVariableToken(parent);
if (!expr)
return;
if (expr->exprId() == 0)
return;
const Token* endOfVarScope = ValueFlow::getEndOfExprScope(expr);
// Only forward lifetime values
std::list<ValueFlow::Value> values = parent->astOperand2()->values();
values.remove_if(&isNotLifetimeValue);
// Dont forward lifetimes that overlap
values.remove_if([&](const ValueFlow::Value& value) {
return findAstNode(value.tokvalue, [&](const Token* child) {
return child->exprId() == expr->exprId();
});
});
// Skip RHS
Token* nextExpression = nextAfterAstRightmostLeaf(parent);
if (expr->exprId() > 0) {
valueFlowForward(nextExpression, endOfVarScope->next(), expr, values, tokenlist, settings);
for (ValueFlow::Value& val : values) {
if (val.lifetimeKind == ValueFlow::Value::LifetimeKind::Address)
val.lifetimeKind = ValueFlow::Value::LifetimeKind::SubObject;
}
// TODO: handle `[`
if (Token::simpleMatch(parent->astOperand1(), ".")) {
const Token* parentLifetime =
getParentLifetime(tokenlist.isCPP(), parent->astOperand1()->astOperand2(), &settings->library);
if (parentLifetime && parentLifetime->exprId() > 0) {
valueFlowForward(nextExpression, endOfVarScope, parentLifetime, values, tokenlist, 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() && tok->variable()->scope()) {
const Variable *var = tok->variable();
const Token *endOfVarScope = var->scope()->bodyEnd;
std::list<ValueFlow::Value> values = tok->values();
Token *nextExpression = nextAfterAstRightmostLeaf(parent);
// Only forward lifetime values
values.remove_if(&isNotLifetimeValue);
valueFlowForward(nextExpression, endOfVarScope, tok, values, tokenlist, settings);
// Cast
} else if (parent->isCast()) {
std::list<ValueFlow::Value> values = tok->values();
// Only forward lifetime values
values.remove_if(&isNotLifetimeValue);
for (ValueFlow::Value& value:values)
setTokenValue(parent, std::move(value), settings);
valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings);
}
}
struct LifetimeStore {
const Token* argtok{};
std::string message;
ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object;
ErrorPath errorPath;
bool inconclusive{};
bool forward = true;
struct Context {
Token* tok{};
TokenList* tokenlist{};
ErrorLogger* errorLogger{};
const Settings* settings{};
};
LifetimeStore() = default;
LifetimeStore(const Token* argtok,
std::string message,
ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object,
bool inconclusive = false)
: argtok(argtok),
message(std::move(message)),
type(type),
inconclusive(inconclusive)
{}
template<class F>
static void forEach(const std::vector<const Token*>& argtoks,
const std::string& message,
ValueFlow::Value::LifetimeKind type,
F f) {
std::map<const Token*, Context> forwardToks;
for (const Token* arg : argtoks) {
LifetimeStore ls{arg, message, type};
Context c{};
ls.mContext = &c;
ls.forward = false;
f(ls);
if (c.tok)
forwardToks[c.tok] = c;
}
for (const auto& p : forwardToks) {
const Context& c = p.second;
valueFlowForwardLifetime(c.tok, *c.tokenlist, c.errorLogger, c.settings);
}
}
static LifetimeStore fromFunctionArg(const Function * f, const Token *tok, const Variable *var, const TokenList &tokenlist, const Settings* settings, ErrorLogger *errorLogger) {
if (!var)
return LifetimeStore{};
if (!var->isArgument())
return LifetimeStore{};
const int n = getArgumentPos(var, f);
if (n < 0)
return LifetimeStore{};
std::vector<const Token *> args = getArguments(tok);
if (n >= args.size()) {
if (settings->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->expressionString() + "'.", ValueFlow::Value::LifetimeKind::Object};
}
template<class Predicate>
bool byRef(Token* tok,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings,
Predicate pred,
SourceLocation loc = SourceLocation::current()) const
{
if (!argtok)
return false;
bool update = false;
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(argtok)) {
if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive)
continue;
ErrorPath er = errorPath;
er.insert(er.end(), lt.errorPath.cbegin(), lt.errorPath.cend());
if (!lt.token)
return false;
if (!pred(lt.token))
return false;
er.emplace_back(argtok, message);
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::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().cbegin(), tok->values().cend(), value) != tok->values().cend())
return false;
if (settings->debugnormal)
setSourceLocation(value, loc, tok);
setTokenValue(tok, std::move(value), settings);
update = true;
}
if (update && forward)
forwardLifetime(tok, tokenlist, errorLogger, settings);
return update;
}
bool byRef(Token* tok,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings,
SourceLocation loc = SourceLocation::current()) const
{
return byRef(
tok,
tokenlist,
errorLogger,
settings,
[](const Token*) {
return true;
},
loc);
}
template<class Predicate>
bool byVal(Token* tok,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings,
Predicate pred,
SourceLocation loc = SourceLocation::current()) const
{
if (!argtok)
return false;
bool update = false;
if (argtok->values().empty()) {
ErrorPath er;
er.emplace_back(argtok, message);
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(argtok)) {
if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive)
continue;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.tokvalue = lt.token;
value.capturetok = argtok;
value.errorPath = er;
value.lifetimeKind = type;
value.setInconclusive(inconclusive || lt.inconclusive);
const Variable* var = lt.token->variable();
if (var && var->isArgument()) {
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Argument;
} else {
continue;
}
// Don't add the value a second time
if (std::find(tok->values().cbegin(), tok->values().cend(), value) != tok->values().cend())
continue;
if (settings->debugnormal)
setSourceLocation(value, loc, tok);
setTokenValue(tok, std::move(value), settings);
update = true;
}
}
for (const ValueFlow::Value &v : argtok->values()) {
if (!v.isLifetimeValue())
continue;
const Token *tok3 = v.tokvalue;
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(tok3)) {
if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive)
continue;
ErrorPath er = v.errorPath;
er.insert(er.end(), lt.errorPath.cbegin(), lt.errorPath.cend());
if (!lt.token)
return false;
if (!pred(lt.token))
return false;
er.emplace_back(argtok, message);
er.insert(er.end(), errorPath.cbegin(), errorPath.cend());
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.lifetimeScope = v.lifetimeScope;
value.path = v.path;
value.tokvalue = lt.token;
value.capturetok = argtok;
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().cbegin(), tok->values().cend(), value) != tok->values().cend())
continue;
if (settings->debugnormal)
setSourceLocation(value, loc, tok);
setTokenValue(tok, std::move(value), settings);
update = true;
}
}
if (update && forward)
forwardLifetime(tok, tokenlist, errorLogger, settings);
return update;
}
bool byVal(Token* tok,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings,
SourceLocation loc = SourceLocation::current()) const
{
return byVal(
tok,
tokenlist,
errorLogger,
settings,
[](const Token*) {
return true;
},
loc);
}
template<class Predicate>
bool byDerefCopy(Token* tok,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings,
Predicate pred,
SourceLocation loc = SourceLocation::current()) const
{
bool update = false;
if (!settings->certainty.isEnabled(Certainty::inconclusive) && inconclusive)
return update;
if (!argtok)
return update;
if (!tok)
return update;
for (const ValueFlow::Value &v : argtok->values()) {
if (!v.isLifetimeValue())
continue;
const Token *tok2 = v.tokvalue;
ErrorPath er = v.errorPath;
const Variable *var = ValueFlow::getLifetimeVariable(tok2, er);
// TODO: the inserted data is never used
er.insert(er.end(), errorPath.cbegin(), errorPath.cend());
if (!var)
continue;
const Token * const varDeclEndToken = var->declEndToken();
for (const Token *tok3 = tok; tok3 && tok3 != varDeclEndToken; tok3 = tok3->previous()) {
if (tok3->varId() == var->declarationId()) {
update |= LifetimeStore{tok3, message, type, inconclusive}
.byVal(tok, tokenlist, errorLogger, settings, pred, loc);
break;
}
}
}
return update;
}
bool byDerefCopy(Token* tok,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings,
SourceLocation loc = SourceLocation::current()) const
{
return byDerefCopy(
tok,
tokenlist,
errorLogger,
settings,
[](const Token*) {
return true;
},
loc);
}
private:
Context* mContext{};
void forwardLifetime(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings) const {
if (mContext) {
mContext->tok = tok;
mContext->tokenlist = &tokenlist;
mContext->errorLogger = errorLogger;
mContext->settings = settings;
}
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
};
static bool hasBorrowingVariables(const std::list<Variable>& vars, const std::vector<const Token*>& args, int depth = 10)
{
if (depth < 0)
return true;
return std::any_of(vars.cbegin(), vars.cend(), [&](const Variable& var) {
if (const ValueType* vt = var.valueType()) {
if (vt->pointer > 0 &&
std::none_of(args.begin(), args.end(), [vt](const Token* arg) {
return arg->valueType() && arg->valueType()->type == vt->type;
}))
return false;
if (vt->pointer > 0)
return true;
if (vt->reference != Reference::None)
return true;
if (vt->isPrimitive())
return false;
if (vt->isEnum())
return false;
// TODO: Check container inner type
if (vt->type == ValueType::CONTAINER && vt->container)
return vt->container->view;
if (vt->typeScope)
return hasBorrowingVariables(vt->typeScope->varlist, args, depth - 1);
}
return true;
});
}
static void valueFlowLifetimeUserConstructor(Token* tok,
const Function* constructor,
const std::string& name,
const std::vector<const Token*>& args,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings)
{
if (!constructor)
return;
std::unordered_map<const Token*, const Variable*> argToParam;
for (std::size_t i = 0; i < args.size(); i++)
argToParam[args[i]] = constructor->getArgumentVar(i);
if (const Token* initList = constructor->constructorMemberInitialization()) {
std::unordered_map<const Variable*, LifetimeCapture> paramCapture;
for (const Token* tok2 : astFlatten(initList->astOperand2(), ",")) {
if (!Token::simpleMatch(tok2, "("))
continue;
if (!tok2->astOperand1())
continue;
if (!tok2->astOperand2())
continue;
const Variable* var = tok2->astOperand1()->variable();
const Token* expr = tok2->astOperand2();
if (!var)
continue;
if (!ValueFlow::isLifetimeBorrowed(expr, settings))
continue;
const Variable* argvar = ValueFlow::getLifetimeVariable(expr);
if (var->isReference() || var->isRValueReference()) {
if (argvar && argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) {
paramCapture[argvar] = LifetimeCapture::ByReference;
}
} else {
bool found = false;
for (const ValueFlow::Value& v : expr->values()) {
if (!v.isLifetimeValue())
continue;
if (v.path > 0)
continue;
if (!v.tokvalue)
continue;
const Variable* lifeVar = v.tokvalue->variable();
if (!lifeVar)
continue;
LifetimeCapture c = LifetimeCapture::Undefined;
if (!v.isArgumentLifetimeValue() && (lifeVar->isReference() || lifeVar->isRValueReference()))
c = LifetimeCapture::ByReference;
else if (v.isArgumentLifetimeValue())
c = LifetimeCapture::ByValue;
if (c != LifetimeCapture::Undefined) {
paramCapture[lifeVar] = c;
found = true;
}
}
if (!found && argvar && argvar->isArgument())
paramCapture[argvar] = LifetimeCapture::ByValue;
}
}
// TODO: Use SubExpressionAnalyzer for members
LifetimeStore::forEach(args,
"Passed to constructor of '" + name + "'.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
const Variable* paramVar = argToParam.at(ls.argtok);
if (paramCapture.count(paramVar) == 0)
return;
const LifetimeCapture c = paramCapture.at(paramVar);
if (c == LifetimeCapture::ByReference)
ls.byRef(tok, tokenlist, errorLogger, settings);
else
ls.byVal(tok, tokenlist, errorLogger, settings);
});
} else if (hasBorrowingVariables(constructor->nestedIn->varlist, args)) {
LifetimeStore::forEach(args,
"Passed to constructor of '" + name + "'.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](LifetimeStore& ls) {
ls.inconclusive = true;
const Variable* var = argToParam.at(ls.argtok);
if (var && !var->isConst() && var->isReference())
ls.byRef(tok, tokenlist, errorLogger, settings);
else
ls.byVal(tok, tokenlist, errorLogger, settings);
});
}
}
static void valueFlowLifetimeFunction(Token *tok, TokenList &tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
if (!Token::Match(tok, "%name% ("))
return;
Token* memtok = nullptr;
if (Token::Match(tok->astParent(), ". %name% (") && astIsRHS(tok))
memtok = tok->astParent()->astOperand1();
const 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];
bool forward = false;
for (ValueFlow::Value val : argTok->values()) {
if (!val.isLifetimeValue())
continue;
val.errorPath.emplace_back(argTok, "Passed to '" + tok->str() + "'.");
setTokenValue(tok->next(), std::move(val), settings);
forward = true;
}
// Check if lifetime is available to avoid adding the lifetime twice
if (forward) {
valueFlowForwardLifetime(tok, 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|bind")) {
for (const Token *argtok : getArguments(tok)) {
LifetimeStore{argtok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}.byVal(
tok->next(), tokenlist, errorLogger, settings);
}
} else if (memtok && Token::Match(tok->astParent(), ". push_back|push_front|insert|push|assign") &&
astIsContainer(memtok)) {
std::vector<const Token *> args = getArguments(tok);
const 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 '" + memtok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}
.byDerefCopy(memtok, tokenlist, errorLogger, settings);
} else if (!args.empty() && ValueFlow::isLifetimeBorrowed(args.back(), settings)) {
LifetimeStore{
args.back(), "Added to container '" + memtok->str() + "'.", ValueFlow::Value::LifetimeKind::Object}
.byVal(memtok, tokenlist, errorLogger, settings);
}
} else if (tok->function()) {
const Function *f = tok->function();
if (f->isConstructor()) {
valueFlowLifetimeUserConstructor(tok->next(), f, tok->str(), getArguments(tok), tokenlist, errorLogger, settings);
return;
}
if (Function::returnsReference(f))
return;
std::vector<const Token*> returns = Function::findReturns(f);
const bool inconclusive = returns.size() > 1;
bool update = false;
for (const Token* returnTok : returns) {
if (returnTok == tok)
continue;
const Variable *returnVar = ValueFlow::getLifetimeVariable(returnTok);
if (returnVar && returnVar->isArgument() && (returnVar->isConst() || !isVariableChanged(returnVar, settings, tokenlist.isCPP()))) {
LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, returnVar, tokenlist, settings, errorLogger);
ls.inconclusive = inconclusive;
ls.forward = false;
update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings);
}
for (const ValueFlow::Value &v : returnTok->values()) {
if (!v.isLifetimeValue())
continue;
if (!v.tokvalue)
continue;
if (memtok &&
(contains({ValueFlow::Value::LifetimeScope::ThisPointer, ValueFlow::Value::LifetimeScope::ThisValue},
v.lifetimeScope) ||
exprDependsOnThis(v.tokvalue))) {
LifetimeStore ls = LifetimeStore{memtok,
"Passed to member function '" + tok->expressionString() + "'.",
ValueFlow::Value::LifetimeKind::Object};
ls.inconclusive = inconclusive;
ls.forward = false;
ls.errorPath = v.errorPath;
ls.errorPath.emplace_front(returnTok, "Return " + lifetimeType(returnTok, &v) + ".");
int thisIndirect = v.lifetimeScope == ValueFlow::Value::LifetimeScope::ThisValue ? 0 : 1;
if (derefShared(memtok->astParent()))
thisIndirect--;
if (thisIndirect == -1)
update |= ls.byDerefCopy(tok->next(), tokenlist, errorLogger, settings);
else if (thisIndirect == 0)
update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings);
else if (thisIndirect == 1)
update |= ls.byRef(tok->next(), tokenlist, errorLogger, settings);
continue;
}
const Variable *var = v.tokvalue->variable();
LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, var, tokenlist, settings, errorLogger);
if (!ls.argtok)
continue;
ls.forward = false;
ls.inconclusive = inconclusive;
ls.errorPath = v.errorPath;
ls.errorPath.emplace_front(returnTok, "Return " + lifetimeType(returnTok, &v) + ".");
if (!v.isArgumentLifetimeValue() && (var->isReference() || var->isRValueReference())) {
update |= ls.byRef(tok->next(), tokenlist, errorLogger, settings);
} else if (v.isArgumentLifetimeValue()) {
update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings);
}
}
}
if (update)
valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings);
} else if (tok->valueType()) {
// TODO: Propagate lifetimes with library functions
if (settings->library.getFunction(tok->previous()))
return;
// Assume constructing the valueType
valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings);
valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings);
} else {
const std::string& retVal = settings->library.returnValue(tok);
if (startsWith(retVal, "arg")) {
std::size_t iArg{};
try {
iArg = strToInt<std::size_t>(retVal.substr(3));
} catch (...) {
return;
}
std::vector<const Token*> args = getArguments(tok);
if (iArg > 0 && iArg <= args.size()) {
const Token* varTok = args[iArg - 1];
if (varTok->variable() && varTok->variable()->isLocal())
LifetimeStore{ varTok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Address }.byRef(
tok->next(), tokenlist, errorLogger, settings);
}
}
}
}
static bool isScope(const Token* tok)
{
if (!tok)
return false;
if (!Token::simpleMatch(tok, "{"))
return false;
const Scope* scope = tok->scope();
if (!scope)
return false;
if (!scope->bodyStart)
return false;
return scope->bodyStart == tok;
}
static const Function* findConstructor(const Scope* scope, const Token* tok, const std::vector<const Token*>& args)
{
if (!tok)
return nullptr;
const Function* f = tok->function();
if (!f && tok->astOperand1())
f = tok->astOperand1()->function();
// Search for a constructor
if (!f || !f->isConstructor()) {
f = nullptr;
std::vector<const Function*> candidates;
for (const Function& function : scope->functionList) {
if (function.minArgCount() > args.size())
continue;
if (!function.isConstructor())
continue;
candidates.push_back(&function);
}
// TODO: Narrow the candidates
if (candidates.size() == 1)
f = candidates.front();
}
if (!f)
return nullptr;
return f;
}
static void valueFlowLifetimeClassConstructor(Token* tok,
const Type* t,
TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings)
{
if (!Token::Match(tok, "(|{"))
return;
if (isScope(tok))
return;
if (!t) {
if (tok->valueType() && tok->valueType()->type != ValueType::RECORD)
return;
if (tok->str() != "{" && !Token::Match(tok->previous(), "%var% (") && !isVariableDecl(tok->previous()))
return;
// If the type is unknown then assume it captures by value in the
// constructor, but make each lifetime inconclusive
std::vector<const Token*> args = getArguments(tok);
LifetimeStore::forEach(args,
"Passed to initializer list.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](LifetimeStore& ls) {
ls.inconclusive = true;
ls.byVal(tok, tokenlist, errorLogger, settings);
});
return;
}
const Scope* scope = t->classScope;
if (!scope)
return;
// Aggregate constructor
if (t->derivedFrom.empty() && (t->isClassType() || t->isStructType())) {
std::vector<const Token*> args = getArguments(tok);
if (scope->numConstructors == 0) {
auto it = scope->varlist.cbegin();
LifetimeStore::forEach(
args,
"Passed to constructor of '" + t->name() + "'.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
// Skip static variable
it = std::find_if(it, scope->varlist.cend(), [](const Variable& var) {
return !var.isStatic();
});
if (it == scope->varlist.cend())
return;
const Variable& var = *it;
if (var.isReference() || var.isRValueReference()) {
ls.byRef(tok, tokenlist, errorLogger, settings);
} else if (ValueFlow::isLifetimeBorrowed(ls.argtok, settings)) {
ls.byVal(tok, tokenlist, errorLogger, settings);
}
it++;
});
} else {
const Function* constructor = findConstructor(scope, tok, args);
valueFlowLifetimeUserConstructor(tok, constructor, t->name(), args, tokenlist, errorLogger, settings);
}
}
}
static void valueFlowLifetimeConstructor(Token* tok, TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings)
{
if (!Token::Match(tok, "(|{"))
return;
if (isScope(tok))
return;
std::vector<ValueType> vts;
if (tok->valueType()) {
vts = {*tok->valueType()};
} else if (Token::Match(tok->previous(), "%var% {|(") && isVariableDecl(tok->previous()) &&
tok->previous()->valueType()) {
vts = {*tok->previous()->valueType()};
} else if (Token::simpleMatch(tok, "{") && !Token::Match(tok->previous(), "%name%")) {
vts = getParentValueTypes(tok, settings);
}
for (const ValueType& vt : vts) {
if (vt.pointer > 0) {
std::vector<const Token*> args = getArguments(tok);
LifetimeStore::forEach(args,
"Passed to initializer list.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
ls.byVal(tok, tokenlist, errorLogger, settings);
});
} else if (vt.container && vt.type == ValueType::CONTAINER) {
std::vector<const Token*> args = getArguments(tok);
if (args.size() == 1 && vt.container->view && astIsContainerOwned(args.front())) {
LifetimeStore{args.front(), "Passed to container view.", ValueFlow::Value::LifetimeKind::SubObject}
.byRef(tok, tokenlist, errorLogger, settings);
} else if (args.size() == 2 && astIsIterator(args[0]) && astIsIterator(args[1])) {
LifetimeStore::forEach(
args,
"Passed to initializer list.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
ls.byDerefCopy(tok, tokenlist, errorLogger, settings);
});
} else if (vt.container->hasInitializerListConstructor) {
LifetimeStore::forEach(args,
"Passed to initializer list.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
ls.byVal(tok, tokenlist, errorLogger, settings);
});
}
} else {
const Type* t = nullptr;
if (vt.typeScope && vt.typeScope->definedType)
t = vt.typeScope->definedType;
else
t = Token::typeOf(tok->previous());
valueFlowLifetimeClassConstructor(tok, t, tokenlist, errorLogger, settings);
}
}
}
struct Lambda {
explicit Lambda(const Token* tok)
{
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;
}
for (const Token* c:getCaptures()) {
if (Token::Match(c, "this !!.")) {
explicitCaptures[c->variable()] = std::make_pair(c, LifetimeCapture::ByReference);
} else if (Token::simpleMatch(c, "* this")) {
explicitCaptures[c->next()->variable()] = std::make_pair(c->next(), LifetimeCapture::ByValue);
} else if (c->variable()) {
explicitCaptures[c->variable()] = std::make_pair(c, LifetimeCapture::ByValue);
} else if (c->isUnaryOp("&") && Token::Match(c->astOperand1(), "%var%")) {
explicitCaptures[c->astOperand1()->variable()] =
std::make_pair(c->astOperand1(), LifetimeCapture::ByReference);
} else {
const std::string& s = c->expressionString();
if (s == "=")
implicitCapture = LifetimeCapture::ByValue;
else if (s == "&")
implicitCapture = LifetimeCapture::ByReference;
}
}
}
const Token* capture{};
const Token* arguments{};
const Token* returnTok{};
const Token* bodyTok{};
std::unordered_map<const Variable*, std::pair<const Token*, LifetimeCapture>> explicitCaptures;
LifetimeCapture implicitCapture = LifetimeCapture::Undefined;
std::vector<const Token*> getCaptures() const {
return getArguments(capture);
}
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 bool isConvertedToView(const Token* tok, const Settings* settings)
{
std::vector<ValueType> vtParents = getParentValueTypes(tok, settings);
return std::any_of(vtParents.cbegin(), vtParents.cend(), [&](const ValueType& vt) {
if (!vt.container)
return false;
return vt.container->view;
});
}
static bool isContainerOfPointers(const Token* tok, const Settings* settings)
{
if (!tok)
{
return true;
}
ValueType vt = ValueType::parseDecl(tok, *settings);
return vt.pointer > 0;
}
static void valueFlowLifetime(TokenList &tokenlist, 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);
// Lambdas
if (lam.isLambda()) {
const Scope * bodyScope = lam.bodyTok->scope();
std::set<const Scope *> scopes;
// Avoid capturing a variable twice
std::set<nonneg int> varids;
bool capturedThis = false;
auto isImplicitCapturingVariable = [&](const Token *varTok) {
const Variable *var = varTok->variable();
if (!var)
return false;
if (varids.count(var->declarationId()) > 0)
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);
varids.insert(var->declarationId());
return true;
};
bool update = false;
auto captureVariable = [&](const Token* tok2, LifetimeCapture c, const std::function<bool(const Token*)> &pred) {
if (varids.count(tok->varId()) > 0)
return;
if (c == LifetimeCapture::ByReference) {
LifetimeStore ls{
tok2, "Lambda captures variable by reference here.", ValueFlow::Value::LifetimeKind::Lambda};
ls.forward = false;
update |= ls.byRef(tok, tokenlist, errorLogger, settings, pred);
} else if (c == LifetimeCapture::ByValue) {
LifetimeStore ls{
tok2, "Lambda captures variable by value here.", ValueFlow::Value::LifetimeKind::Lambda};
ls.forward = false;
update |= ls.byVal(tok, tokenlist, errorLogger, settings, pred);
pred(tok2);
}
};
auto captureThisVariable = [&](const Token* tok2, LifetimeCapture c) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
if (c == LifetimeCapture::ByReference)
value.lifetimeScope = ValueFlow::Value::LifetimeScope::ThisPointer;
else if (c == LifetimeCapture::ByValue)
value.lifetimeScope = ValueFlow::Value::LifetimeScope::ThisValue;
value.tokvalue = tok2;
value.errorPath.emplace_back(tok2, "Lambda captures the 'this' variable here.");
value.lifetimeKind = ValueFlow::Value::LifetimeKind::Lambda;
capturedThis = true;
// Don't add the value a second time
if (std::find(tok->values().cbegin(), tok->values().cend(), value) != tok->values().cend())
return;
setTokenValue(tok, std::move(value), settings);
update |= true;
};
// Handle explicit capture
for (const auto& p:lam.explicitCaptures) {
const Variable* var = p.first;
const Token* tok2 = p.second.first;
const LifetimeCapture c = p.second.second;
if (Token::Match(tok2, "this !!.")) {
captureThisVariable(tok2, c);
} else if (var) {
captureVariable(tok2, c, [](const Token*) {
return true;
});
varids.insert(var->declarationId());
}
}
auto isImplicitCapturingThis = [&](const Token* tok2) {
if (capturedThis)
return false;
if (Token::simpleMatch(tok2, "this"))
return true;
if (tok2->variable()) {
if (Token::simpleMatch(tok2->previous(), "."))
return false;
const Variable* var = tok2->variable();
if (var->isLocal())
return false;
if (var->isArgument())
return false;
return exprDependsOnThis(tok2);
}
if (Token::simpleMatch(tok2, "("))
return exprDependsOnThis(tok2);
return false;
};
for (const Token * tok2 = lam.bodyTok; tok2 != lam.bodyTok->link(); tok2 = tok2->next()) {
if (isImplicitCapturingThis(tok2)) {
captureThisVariable(tok2, LifetimeCapture::ByReference);
} else if (tok2->variable()) {
captureVariable(tok2, lam.implicitCapture, isImplicitCapturingVariable);
}
}
if (update)
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
// address of
else if (tok->isUnaryOp("&")) {
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(tok->astOperand1())) {
if (!settings->certainty.isEnabled(Certainty::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, std::move(value), settings);
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
// Converting to container view
else if (astIsContainerOwned(tok) && isConvertedToView(tok, settings)) {
LifetimeStore ls =
LifetimeStore{tok, "Converted to container view", ValueFlow::Value::LifetimeKind::SubObject};
ls.byRef(tok, tokenlist, errorLogger, settings);
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
// container lifetimes
else if (astIsContainer(tok)) {
Token * parent = astParentSkipParens(tok);
if (!parent)
continue;
if (!Token::Match(parent, ". %name% (") && !Token::Match(parent->previous(), "%name% ("))
continue;
// Skip if its a free function that doesnt yield an iterator to the container
if (Token::Match(parent->previous(), "%name% (") &&
!contains({Library::Container::Yield::START_ITERATOR, Library::Container::Yield::END_ITERATOR},
astFunctionYield(parent->previous(), settings)))
continue;
ValueFlow::Value master;
master.valueType = ValueFlow::Value::ValueType::LIFETIME;
master.lifetimeScope = ValueFlow::Value::LifetimeScope::Local;
if (astIsIterator(parent->tokAt(2))) {
master.errorPath.emplace_back(parent->tokAt(2), "Iterator to container is created here.");
master.lifetimeKind = ValueFlow::Value::LifetimeKind::Iterator;
} else if (astIsIterator(parent) && Token::Match(parent->previous(), "%name% (") &&
contains({Library::Container::Yield::START_ITERATOR, Library::Container::Yield::END_ITERATOR},
astFunctionYield(parent->previous(), settings))) {
master.errorPath.emplace_back(parent, "Iterator to container is created here.");
master.lifetimeKind = ValueFlow::Value::LifetimeKind::Iterator;
} else if ((astIsPointer(parent->tokAt(2)) &&
!isContainerOfPointers(tok->valueType()->containerTypeToken, settings)) ||
Token::Match(parent->next(), "data|c_str")) {
master.errorPath.emplace_back(parent->tokAt(2), "Pointer to container is created here.");
master.lifetimeKind = ValueFlow::Value::LifetimeKind::Object;
} else {
continue;
}
std::vector<const Token*> toks;
if (tok->isUnaryOp("*") || parent->originalName() == "->") {
for (const ValueFlow::Value& v : tok->values()) {
if (!v.isLocalLifetimeValue())
continue;
if (v.lifetimeKind != ValueFlow::Value::LifetimeKind::Address)
continue;
if (!v.tokvalue)
continue;
toks.push_back(v.tokvalue);
}
} else if (astIsContainerView(tok)) {
for (const ValueFlow::Value& v : tok->values()) {
if (!v.isLocalLifetimeValue())
continue;
if (!v.tokvalue)
continue;
if (!astIsContainerOwned(v.tokvalue))
continue;
toks.push_back(v.tokvalue);
}
} else {
toks = {tok};
}
for (const Token* tok2 : toks) {
for (const ReferenceToken& rt : followAllReferences(tok2, false)) {
ValueFlow::Value value = master;
value.tokvalue = rt.token;
value.errorPath.insert(value.errorPath.begin(), rt.errors.cbegin(), rt.errors.cend());
if (Token::simpleMatch(parent, "("))
setTokenValue(parent, value, settings);
else
setTokenValue(parent->tokAt(2), value, settings);
if (!rt.token->variable()) {
LifetimeStore ls = LifetimeStore{
rt.token, master.errorPath.back().second, ValueFlow::Value::LifetimeKind::Object};
ls.byRef(parent->tokAt(2), tokenlist, errorLogger, settings);
}
}
}
valueFlowForwardLifetime(parent->tokAt(2), tokenlist, errorLogger, settings);
}
// Check constructors
else if (Token::Match(tok, "=|return|%name%|{|,|> {") && !isScope(tok->next())) {
valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings);
}
// Check function calls
else if (Token::Match(tok, "%name% (") && !Token::simpleMatch(tok->next()->link(), ") {")) {
valueFlowLifetimeFunction(tok, tokenlist, errorLogger, settings);
}
// Unique pointer lifetimes
else if (astIsUniqueSmartPointer(tok) && astIsLHS(tok) && Token::simpleMatch(tok->astParent(), ". get ( )")) {
Token* ptok = tok->astParent()->tokAt(2);
ErrorPath errorPath = {{ptok, "Raw pointer to smart pointer created here."}};
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local;
value.lifetimeKind = ValueFlow::Value::LifetimeKind::SubObject;
value.tokvalue = tok;
value.errorPath = errorPath;
setTokenValue(ptok, std::move(value), settings);
valueFlowForwardLifetime(ptok, tokenlist, errorLogger, settings);
}
// Check variables
else if (tok->variable()) {
ErrorPath errorPath;
const Variable * var = ValueFlow::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, std::move(value), settings);
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
// Forward any lifetimes
else if (std::any_of(tok->values().cbegin(), tok->values().cend(), 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 <")) {
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().empty();
}
static Token* findOpenParentesisOfMove(Token* moveVarTok)
{
Token* tok = moveVarTok;
while (tok && tok->str() != "(")
tok = tok->previous();
return tok;
}
static Token* findEndOfFunctionCallForParameter(Token* parameterToken)
{
if (!parameterToken)
return nullptr;
Token* parent = parameterToken->astParent();
while (parent && !parent->isOp() && !Token::Match(parent, "[({]"))
parent = parent->astParent();
if (!parent)
return nullptr;
return nextAfterAstRightmostLeaf(parent);
}
static void valueFlowAfterMove(TokenList& tokenlist, const SymbolDatabase& symboldatabase, 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().empty()) {
varTok = tok;
const Variable *var = tok->variable();
if (!var || (!var->isLocal() && !var->isArgument()))
continue;
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();
setTokenValue(tok, value, settings);
if (var->scope()) {
const Token* const endOfVarScope = var->scope()->bodyEnd;
valueFlowForward(tok->next(), endOfVarScope, tok, std::move(value), tokenlist, settings);
}
continue;
}
ValueFlow::Value::MoveKind moveKind;
if (!isStdMoveOrStdForwarded(tok, &moveKind, &varTok))
continue;
const nonneg 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 Token* const endOfVarScope = ValueFlow::getEndOfExprScope(varTok);
Token* openParentesisOfMove = findOpenParentesisOfMove(varTok);
Token* endOfFunctionCall = findEndOfFunctionCallForParameter(openParentesisOfMove);
if (endOfFunctionCall) {
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();
valueFlowForward(endOfFunctionCall, endOfVarScope, varTok, std::move(value), tokenlist, settings);
}
}
}
}
static const Token* findIncompleteVar(const Token* start, const Token* end)
{
for (const Token* tok = start; tok != end; tok = tok->next()) {
if (tok->isIncompleteVar())
return tok;
}
return nullptr;
}
static ValueFlow::Value makeConditionValue(long long val,
const Token* condTok,
bool assume,
bool impossible = false,
const Settings* settings = nullptr,
SourceLocation loc = SourceLocation::current())
{
ValueFlow::Value v(val);
v.setKnown();
if (impossible) {
v.intvalue = !v.intvalue;
v.setImpossible();
}
v.condition = condTok;
if (assume)
v.errorPath.emplace_back(condTok, "Assuming condition '" + condTok->expressionString() + "' is true");
else
v.errorPath.emplace_back(condTok, "Assuming condition '" + condTok->expressionString() + "' is false");
if (settings && settings->debugnormal)
setSourceLocation(v, loc, condTok);
return v;
}
static std::vector<const Token*> getConditions(const Token* tok, const char* op)
{
std::vector<const Token*> conds = {tok};
if (tok->str() == op) {
std::vector<const Token*> args = astFlatten(tok, op);
std::copy_if(args.cbegin(), args.cend(), std::back_inserter(conds), [&](const Token* tok2) {
if (tok2->exprId() == 0)
return false;
if (tok2->hasKnownIntValue())
return false;
if (Token::Match(tok2, "%var%|.") && !astIsBool(tok2))
return false;
return true;
});
}
return conds;
}
static bool isBreakOrContinueScope(const Token* endToken)
{
if (!Token::simpleMatch(endToken, "}"))
return false;
return Token::Match(endToken->tokAt(-2), "break|continue ;");
}
static const Scope* getLoopScope(const Token* tok)
{
if (!tok)
return nullptr;
const Scope* scope = tok->scope();
while (scope && scope->type != Scope::eWhile && scope->type != Scope::eFor && scope->type != Scope::eDo)
scope = scope->nestedIn;
return scope;
}
//
static void valueFlowConditionExpressions(const TokenList &tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger *errorLogger, const Settings &settings)
{
for (const Scope * scope : symboldatabase.functionScopes) {
if (const Token* incompleteTok = findIncompleteVar(scope->bodyStart, scope->bodyEnd)) {
if (settings.debugwarnings)
bailoutIncompleteVar(tokenlist, errorLogger, incompleteTok, "Skipping function due to incomplete variable " + incompleteTok->str());
break;
}
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::simpleMatch(tok, "if ("))
continue;
Token* parenTok = tok->next();
if (!Token::simpleMatch(parenTok->link(), ") {"))
continue;
Token * blockTok = parenTok->link()->tokAt(1);
const Token* condTok = parenTok->astOperand2();
if (condTok->exprId() == 0)
continue;
if (condTok->hasKnownIntValue())
continue;
if (!isConstExpression(condTok, settings.library, tokenlist.isCPP()))
continue;
const bool is1 = (condTok->isComparisonOp() || condTok->tokType() == Token::eLogicalOp || astIsBool(condTok));
Token* startTok = blockTok;
// Inner condition
{
for (const Token* condTok2 : getConditions(condTok, "&&")) {
if (is1) {
const bool isBool = astIsBool(condTok2) || Token::Match(condTok2, "%comp%|%oror%|&&");
SameExpressionAnalyzer a1(condTok2, makeConditionValue(1, condTok2, /*assume*/ true, !isBool), tokenlist, &settings); // don't set '1' for non-boolean expressions
valueFlowGenericForward(startTok, startTok->link(), a1, settings);
}
OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(0, condTok2, true), tokenlist, &settings);
valueFlowGenericForward(startTok, startTok->link(), a2, settings);
}
}
std::vector<const Token*> conds = getConditions(condTok, "||");
// Check else block
if (Token::simpleMatch(startTok->link(), "} else {")) {
startTok = startTok->link()->tokAt(2);
for (const Token* condTok2:conds) {
SameExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist, &settings);
valueFlowGenericForward(startTok, startTok->link(), a1, settings);
if (is1) {
OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist, &settings);
valueFlowGenericForward(startTok, startTok->link(), a2, settings);
}
}
}
// Check if the block terminates early
if (isEscapeScope(blockTok, &settings)) {
const Scope* scope2 = scope;
// If escaping a loop then only use the loop scope
if (isBreakOrContinueScope(blockTok->link())) {
scope2 = getLoopScope(blockTok->link());
if (!scope2)
continue;
}
for (const Token* condTok2:conds) {
SameExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist, &settings);
valueFlowGenericForward(startTok->link()->next(), scope2->bodyEnd, a1, settings);
if (is1) {
OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist, &settings);
valueFlowGenericForward(startTok->link()->next(), scope2->bodyEnd, a2, settings);
}
}
}
}
}
}
static bool isTruncated(const ValueType* src, const ValueType* dst, const Settings* settings)
{
if (src->pointer > 0 || dst->pointer > 0)
return src->pointer != dst->pointer;
if (src->smartPointer && dst->smartPointer)
return false;
if ((src->isIntegral() && dst->isIntegral()) || (src->isFloat() && dst->isFloat())) {
const size_t srcSize = ValueFlow::getSizeOf(*src, settings);
const size_t dstSize = ValueFlow::getSizeOf(*dst, settings);
if (srcSize > dstSize)
return true;
if (srcSize == dstSize && src->sign != dst->sign)
return true;
} else if (src->type == dst->type) {
if (src->type == ValueType::Type::RECORD)
return src->typeScope != dst->typeScope;
} else {
return true;
}
return false;
}
static void setSymbolic(ValueFlow::Value& value, const Token* tok)
{
assert(tok && tok->exprId() > 0 && "Missing expr id for symbolic value");
value.valueType = ValueFlow::Value::ValueType::SYMBOLIC;
value.tokvalue = tok;
}
static ValueFlow::Value makeSymbolic(const Token* tok, MathLib::bigint delta = 0)
{
ValueFlow::Value value;
value.setKnown();
setSymbolic(value, tok);
value.intvalue = delta;
return value;
}
static std::set<nonneg int> getVarIds(const Token* tok)
{
std::set<nonneg int> result;
visitAstNodes(tok, [&](const Token* child) {
if (child->varId() > 0)
result.insert(child->varId());
return ChildrenToVisit::op1_and_op2;
});
return result;
}
static void valueFlowSymbolic(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings)
{
for (const Scope* scope : symboldatabase.functionScopes) {
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::simpleMatch(tok, "="))
continue;
if (tok->astParent())
continue;
if (!tok->astOperand1())
continue;
if (!tok->astOperand2())
continue;
if (tok->astOperand1()->hasKnownIntValue())
continue;
if (tok->astOperand2()->hasKnownIntValue())
continue;
if (tok->astOperand1()->exprId() == 0)
continue;
if (tok->astOperand2()->exprId() == 0)
continue;
if (!isConstExpression(tok->astOperand2(), settings->library, tokenlist.isCPP()))
continue;
if (tok->astOperand1()->valueType() && tok->astOperand2()->valueType()) {
if (isTruncated(
tok->astOperand2()->valueType(), tok->astOperand1()->valueType(), settings))
continue;
} else if (isDifferentType(tok->astOperand2(), tok->astOperand1())) {
continue;
}
const std::set<nonneg int> rhsVarIds = getVarIds(tok->astOperand2());
const std::vector<const Variable*> vars = getLHSVariables(tok);
if (std::any_of(vars.cbegin(), vars.cend(), [&](const Variable* var) {
if (rhsVarIds.count(var->declarationId()) > 0)
return true;
if (var->isLocal())
return var->isStatic();
return !var->isArgument();
}))
continue;
if (findAstNode(tok, [](const Token* child) {
return child->isIncompleteVar();
}))
continue;
Token* start = nextAfterAstRightmostLeaf(tok);
const Token* end = ValueFlow::getEndOfExprScope(tok->astOperand1(), scope);
ValueFlow::Value rhs = makeSymbolic(tok->astOperand2());
rhs.errorPath.emplace_back(tok,
tok->astOperand1()->expressionString() + " is assigned '" +
tok->astOperand2()->expressionString() + "' here.");
valueFlowForward(start, end, tok->astOperand1(), rhs, tokenlist, settings);
ValueFlow::Value lhs = makeSymbolic(tok->astOperand1());
lhs.errorPath.emplace_back(tok,
tok->astOperand1()->expressionString() + " is assigned '" +
tok->astOperand2()->expressionString() + "' here.");
valueFlowForward(start, end, tok->astOperand2(), lhs, tokenlist, settings);
}
}
}
static const Token* isStrlenOf(const Token* tok, const Token* expr, int depth = 10)
{
if (depth < 0)
return nullptr;
if (!tok)
return nullptr;
if (!expr)
return nullptr;
if (expr->exprId() == 0)
return nullptr;
if (Token::simpleMatch(tok->previous(), "strlen (")) {
if (tok->astOperand2()->exprId() == expr->exprId())
return tok;
} else {
for (const ValueFlow::Value& v : tok->values()) {
if (!v.isSymbolicValue())
continue;
if (!v.isKnown())
continue;
if (v.intvalue != 0)
continue;
if (const Token* next = isStrlenOf(v.tokvalue, expr, depth - 1))
return next;
}
}
return nullptr;
}
static ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, MathLib::bigint val);
static void valueFlowSymbolicOperators(const SymbolDatabase& symboldatabase, const Settings* settings)
{
for (const Scope* scope : symboldatabase.functionScopes) {
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
if (Token::Match(tok, "abs|labs|llabs|fabs|fabsf|fabsl (")) {
const Token* arg = tok->next()->astOperand2();
if (!arg)
continue;
if (arg->exprId() == 0)
continue;
ValueFlow::Value c = inferCondition(">=", arg, 0);
if (!c.isKnown())
continue;
ValueFlow::Value v = makeSymbolic(arg);
v.errorPath = c.errorPath;
v.errorPath.emplace_back(tok, "Passed to " + tok->str());
if (c.intvalue == 0)
v.setImpossible();
else
v.setKnown();
setTokenValue(tok->next(), std::move(v), settings);
} else if (Token::Match(tok, "*|/|<<|>>|^|+|-|%or%")) {
if (!tok->astOperand1())
continue;
if (!tok->astOperand2())
continue;
if (!astIsIntegral(tok->astOperand1(), false) && !astIsIntegral(tok->astOperand2(), false))
continue;
const ValueFlow::Value* constant = nullptr;
const Token* vartok = nullptr;
if (tok->astOperand1()->hasKnownIntValue()) {
constant = &tok->astOperand1()->values().front();
vartok = tok->astOperand2();
}
if (tok->astOperand2()->hasKnownIntValue()) {
constant = &tok->astOperand2()->values().front();
vartok = tok->astOperand1();
}
if (!constant)
continue;
if (!vartok)
continue;
if (vartok->exprId() == 0)
continue;
if (Token::Match(tok, "<<|>>|/") && !astIsLHS(vartok))
continue;
if (Token::Match(tok, "<<|>>|^|+|-|%or%") && constant->intvalue != 0)
continue;
if (Token::Match(tok, "*|/") && constant->intvalue != 1)
continue;
std::vector<ValueFlow::Value> values = {makeSymbolic(vartok)};
std::unordered_set<nonneg int> ids = {vartok->exprId()};
std::copy_if(vartok->values().cbegin(),
vartok->values().cend(),
std::back_inserter(values),
[&](const ValueFlow::Value& v) {
if (!v.isSymbolicValue())
return false;
if (!v.tokvalue)
return false;
return ids.insert(v.tokvalue->exprId()).second;
});
for (ValueFlow::Value& v : values)
setTokenValue(tok, std::move(v), settings);
} else if (Token::simpleMatch(tok, "[")) {
const Token* arrayTok = tok->astOperand1();
const Token* indexTok = tok->astOperand2();
if (!arrayTok)
continue;
if (!indexTok)
continue;
for (const ValueFlow::Value& value : indexTok->values()) {
if (!value.isSymbolicValue())
continue;
if (value.intvalue != 0)
continue;
const Token* strlenTok = isStrlenOf(value.tokvalue, arrayTok);
if (!strlenTok)
continue;
ValueFlow::Value v = value;
v.bound = ValueFlow::Value::Bound::Point;
v.valueType = ValueFlow::Value::ValueType::INT;
v.errorPath.emplace_back(strlenTok, "Return index of first '\\0' character in string");
setTokenValue(tok, std::move(v), settings);
}
}
}
}
}
struct SymbolicInferModel : InferModel {
const Token* expr;
explicit SymbolicInferModel(const Token* tok) : expr(tok) {
assert(expr->exprId() != 0);
}
bool match(const ValueFlow::Value& value) const override
{
return value.isSymbolicValue() && value.tokvalue && value.tokvalue->exprId() == expr->exprId();
}
ValueFlow::Value yield(MathLib::bigint value) const override
{
ValueFlow::Value result(value);
result.valueType = ValueFlow::Value::ValueType::SYMBOLIC;
result.tokvalue = expr;
result.setKnown();
return result;
}
};
static void valueFlowSymbolicInfer(const SymbolDatabase& symboldatabase, const Settings* settings)
{
for (const Scope* scope : symboldatabase.functionScopes) {
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "-|%comp%"))
continue;
if (tok->hasKnownIntValue())
continue;
if (!tok->astOperand1())
continue;
if (!tok->astOperand2())
continue;
if (tok->astOperand1()->exprId() == 0)
continue;
if (tok->astOperand2()->exprId() == 0)
continue;
if (tok->astOperand1()->hasKnownIntValue())
continue;
if (tok->astOperand2()->hasKnownIntValue())
continue;
if (astIsFloat(tok->astOperand1(), false))
continue;
if (astIsFloat(tok->astOperand2(), false))
continue;
SymbolicInferModel leftModel{tok->astOperand1()};
std::vector<ValueFlow::Value> values = infer(leftModel, tok->str(), 0, tok->astOperand2()->values());
if (values.empty()) {
SymbolicInferModel rightModel{tok->astOperand2()};
values = infer(rightModel, tok->str(), tok->astOperand1()->values(), 0);
}
for (ValueFlow::Value& value : values) {
setTokenValue(tok, std::move(value), settings);
}
}
}
}
template<class ContainerOfValue>
static void valueFlowForwardConst(Token* start,
const Token* end,
const Variable* var,
const ContainerOfValue& values,
const Settings* const settings,
int /*unused*/ = 0)
{
if (!precedes(start, end))
throw InternalError(var->nameToken(), "valueFlowForwardConst: start token does not precede the end token.");
for (Token* tok = start; tok != end; tok = tok->next()) {
if (tok->varId() == var->declarationId()) {
for (const ValueFlow::Value& value : values)
setTokenValue(tok, value, settings);
} else {
[&] {
// Follow references
auto refs = followAllReferences(tok);
auto it = std::find_if(refs.cbegin(), refs.cend(), [&](const ReferenceToken& ref) {
return ref.token->varId() == var->declarationId();
});
if (it != refs.end()) {
for (ValueFlow::Value value : values) {
if (refs.size() > 1)
value.setInconclusive();
value.errorPath.insert(value.errorPath.end(), it->errors.cbegin(), it->errors.cend());
setTokenValue(tok, std::move(value), settings);
}
return;
}
// Follow symbolic values
for (const ValueFlow::Value& v : tok->values()) {
if (!v.isSymbolicValue())
continue;
if (!v.tokvalue)
continue;
if (v.tokvalue->varId() != var->declarationId())
continue;
for (ValueFlow::Value value : values) {
if (!v.isKnown() && value.isImpossible())
continue;
if (v.intvalue != 0) {
if (!value.isIntValue())
continue;
value.intvalue += v.intvalue;
}
if (!value.isImpossible())
value.valueKind = v.valueKind;
value.bound = v.bound;
value.errorPath.insert(value.errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend());
setTokenValue(tok, std::move(value), settings);
}
}
}();
}
}
}
static void valueFlowForwardConst(Token* start,
const Token* end,
const Variable* var,
const std::initializer_list<ValueFlow::Value>& values,
const Settings* const settings)
{
valueFlowForwardConst(start, end, var, values, settings, 0);
}
static ValueFlow::Value::Bound findVarBound(const Variable* var,
const Token* start,
const Token* end,
const Settings* settings)
{
ValueFlow::Value::Bound result = ValueFlow::Value::Bound::Point;
const Token* next = start;
while ((next = findExpressionChangedSkipDeadCode(
var->nameToken(), next->next(), end, settings, true, &evaluateKnownValues))) {
ValueFlow::Value::Bound b = ValueFlow::Value::Bound::Point;
if (next->varId() != var->declarationId())
return ValueFlow::Value::Bound::Point;
if (Token::simpleMatch(next->astParent(), "++"))
b = ValueFlow::Value::Bound::Lower;
else if (Token::simpleMatch(next->astParent(), "--"))
b = ValueFlow::Value::Bound::Upper;
else
return ValueFlow::Value::Bound::Point;
if (result == ValueFlow::Value::Bound::Point)
result = b;
else if (result != b)
return ValueFlow::Value::Bound::Point;
}
return result;
}
static bool isInitialVarAssign(const Token* tok)
{
if (!tok)
return false;
if (!tok->variable())
return false;
if (tok->variable()->nameToken() == tok)
return true;
const Token* prev = tok->tokAt(2);
if (!Token::Match(prev, "%var% ; %var%"))
return false;
return tok->varId() == prev->varId() && tok->variable()->nameToken() == prev;
}
static void valueFlowForwardAssign(Token* const tok,
const Token* expr,
std::vector<const Variable*> vars,
std::list<ValueFlow::Value> values,
const bool init,
TokenList& tokenlist,
ErrorLogger* const errorLogger,
const Settings* const settings)
{
if (Token::simpleMatch(tok->astParent(), "return"))
return;
const Token* endOfVarScope = ValueFlow::getEndOfExprScope(expr);
if (std::any_of(values.cbegin(), values.cend(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) {
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
values.remove_if(std::mem_fn(&ValueFlow::Value::isLifetimeValue));
}
if (std::all_of(
vars.cbegin(), vars.cend(), [&](const Variable* var) {
return !var->isPointer() && !var->isSmartPointer();
}))
values.remove_if(std::mem_fn(&ValueFlow::Value::isTokValue));
if (tok->astParent()) {
for (ValueFlow::Value& value : values) {
std::string valueKind;
if (value.valueKind == ValueFlow::Value::ValueKind::Impossible) {
if (value.bound == ValueFlow::Value::Bound::Point)
valueKind = "never ";
else if (value.bound == ValueFlow::Value::Bound::Lower)
valueKind = "less than ";
else if (value.bound == ValueFlow::Value::Bound::Upper)
valueKind = "greater than ";
}
std::string info = "Assignment '" + tok->astParent()->expressionString() + "', assigned value is " + valueKind + value.infoString();
value.errorPath.emplace_back(tok, std::move(info));
}
}
if (tokenlist.isCPP() && vars.size() == 1 && Token::Match(vars.front()->typeStartToken(), "bool|_Bool")) {
for (ValueFlow::Value& value : values) {
if (value.isImpossible())
continue;
if (value.isIntValue())
value.intvalue = (value.intvalue != 0);
if (value.isTokValue())
value.intvalue = (value.tokvalue != nullptr);
}
}
// Static variable initialisation?
if (vars.size() == 1 && vars.front()->isStatic() && init)
lowerToPossible(values);
// is volatile
if (std::any_of(vars.cbegin(), vars.cend(), [&](const Variable* var) {
return var->isVolatile();
}))
lowerToPossible(values);
// Skip RHS
Token* nextExpression = tok->astParent() ? nextAfterAstRightmostLeaf(tok->astParent()) : tok->next();
if (!nextExpression)
return;
for (ValueFlow::Value& value : values) {
if (value.isSymbolicValue())
continue;
if (value.isTokValue())
continue;
value.tokvalue = tok;
}
// Const variable
if (expr->variable() && expr->variable()->isConst() && !expr->variable()->isReference()) {
auto it = std::remove_if(values.begin(), values.end(), [](const ValueFlow::Value& value) {
if (!value.isKnown())
return false;
if (value.isIntValue())
return true;
if (value.isFloatValue())
return true;
if (value.isContainerSizeValue())
return true;
if (value.isIteratorValue())
return true;
return false;
});
std::list<ValueFlow::Value> constValues;
constValues.splice(constValues.end(), values, it, values.end());
valueFlowForwardConst(nextExpression, endOfVarScope, expr->variable(), constValues, settings);
}
if (isInitialVarAssign(expr)) {
// Check if variable is only incremented or decremented
ValueFlow::Value::Bound b = findVarBound(expr->variable(), nextExpression, endOfVarScope, settings);
if (b != ValueFlow::Value::Bound::Point) {
auto knownValueIt = std::find_if(values.begin(), values.end(), [](const ValueFlow::Value& value) {
if (!value.isKnown())
return false;
return value.isIntValue();
});
if (knownValueIt != values.end()) {
ValueFlow::Value value = *knownValueIt;
value.bound = b;
value.invertRange();
value.setImpossible();
valueFlowForwardConst(nextExpression, endOfVarScope, expr->variable(), {value}, settings);
}
}
}
valueFlowForward(nextExpression, endOfVarScope, expr, values, tokenlist, settings);
}
static void valueFlowForwardAssign(Token* const tok,
const Variable* const var,
const std::list<ValueFlow::Value>& values,
const bool /*unused*/,
const bool init,
TokenList& tokenlist,
ErrorLogger* const errorLogger,
const Settings* const settings)
{
valueFlowForwardAssign(tok, var->nameToken(), {var}, values, init, tokenlist, errorLogger, settings);
}
static std::list<ValueFlow::Value> truncateValues(std::list<ValueFlow::Value> values,
const ValueType* dst,
const ValueType* src,
const Settings* settings)
{
if (!dst || !dst->isIntegral())
return values;
const size_t sz = ValueFlow::getSizeOf(*dst, settings);
if (src) {
const size_t osz = ValueFlow::getSizeOf(*src, settings);
if (osz >= sz && dst->sign == ValueType::Sign::SIGNED && src->sign == ValueType::Sign::UNSIGNED) {
values.remove_if([&](const ValueFlow::Value& value) {
if (!value.isIntValue())
return false;
if (!value.isImpossible())
return false;
if (value.bound != ValueFlow::Value::Bound::Upper)
return false;
if (osz == sz && value.intvalue < 0)
return true;
if (osz > sz)
return true;
return false;
});
}
}
for (ValueFlow::Value &value : values) {
// Don't truncate impossible values since those can be outside of the valid range
if (value.isImpossible())
continue;
if (value.isFloatValue()) {
value.intvalue = value.floatValue;
value.valueType = ValueFlow::Value::ValueType::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 (dst->sign == ValueType::Sign::SIGNED && (value.intvalue & signBit))
value.intvalue |= ~unsignedMaxValue;
}
}
return values;
}
static bool isVariableInit(const Token *tok)
{
return (tok->str() == "(" || tok->str() == "{") &&
(tok->isBinaryOp() || (tok->astOperand1() && tok->link() == tok->next())) &&
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(), ",");
}
// Return true if two associative containers intersect
template<class C1, class C2>
static bool intersects(const C1& c1, const C2& c2)
{
if (c1.size() > c2.size())
return intersects(c2, c1);
// NOLINTNEXTLINE(readability-use-anyofallof) - TODO: fix if possible / also Cppcheck false negative
for (auto&& x : c1) {
if (c2.find(x) != c2.end())
return true;
}
return false;
}
static void valueFlowAfterAssign(TokenList &tokenlist,
const SymbolDatabase& symboldatabase,
ErrorLogger *errorLogger,
const Settings *settings,
const std::set<const Scope*>& skippedFunctions)
{
for (const Scope * scope : symboldatabase.functionScopes) {
if (skippedFunctions.count(scope))
continue;
std::unordered_map<nonneg int, std::unordered_set<nonneg int>> backAssigns;
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
// Assignment
bool isInit = false;
if (tok->str() != "=" && !(isInit = isVariableInit(tok)))
continue;
if (tok->astParent() && !((tok->astParent()->str() == ";" && astIsLHS(tok)) || tok->astParent()->str() == "*"))
continue;
// Lhs should be a variable
if (!tok->astOperand1() || !tok->astOperand1()->exprId())
continue;
std::vector<const Variable*> vars = getLHSVariables(tok);
// Rhs values..
Token* rhs = tok->astOperand2();
if (!rhs && isInit)
rhs = tok;
if (!rhs || rhs->values().empty())
continue;
std::list<ValueFlow::Value> values = truncateValues(
rhs->values(), tok->astOperand1()->valueType(), rhs->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() && !value.isSymbolicValue())
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::ValueType::CONTAINER_SIZE;
});
// Remove symbolic values that are the same as the LHS
values.remove_if([&](const ValueFlow::Value& value) {
if (value.isSymbolicValue() && value.tokvalue)
return value.tokvalue->exprId() == tok->astOperand1()->exprId();
return false;
});
// Find references to LHS in RHS
auto isIncremental = [&](const Token* tok2) -> bool {
return findAstNode(tok2,
[&](const Token* child) {
return child->exprId() == tok->astOperand1()->exprId();
});
};
// Check symbolic values as well
const bool incremental = isIncremental(tok->astOperand2()) ||
std::any_of(values.cbegin(), values.cend(), [&](const ValueFlow::Value& value) {
if (!value.isSymbolicValue())
return false;
return isIncremental(value.tokvalue);
});
// Remove values from the same assignment if it is incremental
if (incremental) {
values.remove_if([&](const ValueFlow::Value& value) {
if (value.tokvalue)
return value.tokvalue == tok->astOperand2();
return false;
});
}
// If assignment copy by value, remove Uninit values..
if ((tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->pointer == 0) ||
(tok->astOperand1()->variable() && tok->astOperand1()->variable()->isReference() && tok->astOperand1()->variable()->nameToken() == tok->astOperand1()))
values.remove_if([&](const ValueFlow::Value& value) {
return value.isUninitValue();
});
if (values.empty())
continue;
const bool init = vars.size() == 1 && (vars.front()->nameToken() == tok->astOperand1() || tok->isSplittedVarDeclEq());
valueFlowForwardAssign(
rhs, tok->astOperand1(), vars, values, init, tokenlist, errorLogger, settings);
// Back propagate symbolic values
if (tok->astOperand1()->exprId() > 0) {
Token* start = nextAfterAstRightmostLeaf(tok);
const Token* end = scope->bodyEnd;
// Collect symbolic ids
std::unordered_set<nonneg int> ids;
for (const ValueFlow::Value& value : values) {
if (!value.isSymbolicValue())
continue;
if (!value.tokvalue)
continue;
if (value.tokvalue->exprId() == 0)
continue;
ids.insert(value.tokvalue->exprId());
}
for (ValueFlow::Value value : values) {
if (!value.isSymbolicValue())
continue;
const Token* expr = value.tokvalue;
value.intvalue = -value.intvalue;
value.tokvalue = tok->astOperand1();
// Skip if it intersects with an already assigned symbol
auto& s = backAssigns[value.tokvalue->exprId()];
if (intersects(s, ids))
continue;
s.insert(expr->exprId());
value.errorPath.emplace_back(tok,
tok->astOperand1()->expressionString() + " is assigned '" +
tok->astOperand2()->expressionString() + "' here.");
valueFlowForward(start, end, expr, value, tokenlist, settings);
}
}
}
}
}
static std::vector<const Variable*> getVariables(const Token* tok)
{
std::vector<const Variable*> result;
visitAstNodes(tok, [&](const Token* child) {
if (child->variable())
result.push_back(child->variable());
return ChildrenToVisit::op1_and_op2;
});
return result;
}
static void valueFlowAfterSwap(TokenList& tokenlist,
const 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()) {
if (!Token::simpleMatch(tok, "swap ("))
continue;
if (!Token::simpleMatch(tok->next()->astOperand2(), ","))
continue;
std::vector<Token*> args = astFlatten(tok->next()->astOperand2(), ",");
if (args.size() != 2)
continue;
if (args[0]->exprId() == 0)
continue;
if (args[1]->exprId() == 0)
continue;
for (int i = 0; i < 2; i++) {
std::vector<const Variable*> vars = getVariables(args[0]);
const std::list<ValueFlow::Value>& values = args[0]->values();
valueFlowForwardAssign(args[0], args[1], vars, values, false, tokenlist, errorLogger, settings);
std::swap(args[0], args[1]);
}
}
}
}
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);
}
ValueFlow::Value ValueFlow::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.cbegin(), input.cend(), std::back_inserter(values), &ValueFlow::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(std::move(value));
}
}
struct ConditionHandler {
struct Condition {
const Token* vartok{};
std::list<ValueFlow::Value> true_values;
std::list<ValueFlow::Value> false_values;
bool inverted = false;
// Whether to insert impossible values for the condition or only use possible values
bool impossible = true;
bool isBool() const {
return astIsBool(vartok);
}
static MathLib::bigint findPath(const std::list<ValueFlow::Value>& values)
{
auto it = std::find_if(values.cbegin(), values.cend(), [](const ValueFlow::Value& v) {
return v.path > 0;
});
if (it == values.end())
return 0;
assert(std::all_of(it, values.end(), [&](const ValueFlow::Value& v) {
return v.path == 0 || v.path == it->path;
}));
return it->path;
}
MathLib::bigint getPath() const
{
assert(std::abs(findPath(true_values) - findPath(false_values)) == 0);
return findPath(true_values) | findPath(false_values);
}
Token* getContextAndValues(Token* condTok,
std::list<ValueFlow::Value>& thenValues,
std::list<ValueFlow::Value>& elseValues,
bool known = false) const
{
const MathLib::bigint path = getPath();
const bool allowKnown = path == 0;
const bool allowImpossible = impossible && allowKnown;
bool inverted2 = inverted;
Token* ctx = skipNotAndCasts(condTok, &inverted2);
bool then = !inverted || !inverted2;
if (!Token::Match(condTok, "!=|=|(|.") && condTok != vartok) {
thenValues.insert(thenValues.end(), true_values.cbegin(), true_values.cend());
if (allowImpossible && (known || isConditionKnown(ctx, !then)))
insertImpossible(elseValues, false_values);
}
if (!Token::Match(condTok, "==|!")) {
elseValues.insert(elseValues.end(), false_values.cbegin(), false_values.cend());
if (allowImpossible && (known || isConditionKnown(ctx, then))) {
insertImpossible(thenValues, true_values);
if (isBool())
insertNegateKnown(thenValues, true_values);
}
}
if (inverted2)
std::swap(thenValues, elseValues);
return ctx;
}
};
virtual std::vector<Condition> parse(const Token* tok, const Settings* settings) const = 0;
virtual Analyzer::Result forward(Token* start,
const Token* stop,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current()) const
{
return valueFlowForward(start->next(), stop, exprTok, values, tokenlist, settings, loc);
}
virtual Analyzer::Result forward(Token* top,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current()) const
{
return valueFlowForwardRecursive(top, exprTok, values, tokenlist, settings, loc);
}
virtual void reverse(Token* start,
const Token* endToken,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList& tokenlist,
const Settings* settings,
SourceLocation loc = SourceLocation::current()) const
{
return valueFlowReverse(start, endToken, exprTok, values, tokenlist, settings, loc);
}
void traverseCondition(const TokenList& tokenlist,
const SymbolDatabase& symboldatabase,
const Settings* settings,
const std::set<const Scope*>& skippedFunctions,
const std::function<void(const Condition& cond, Token* tok, const Scope* scope)>& f) const
{
for (const Scope *scope : symboldatabase.functionScopes) {
if (skippedFunctions.count(scope))
continue;
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, ":|;|,"))
continue;
const Token* top = tok->astTop();
if (!top)
continue;
if (!Token::Match(top->previous(), "if|while|for (") && !Token::Match(tok->astParent(), "&&|%oror%|?|!"))
continue;
for (const Condition& cond : parse(tok, settings)) {
if (!cond.vartok)
continue;
if (cond.vartok->exprId() == 0)
continue;
if (cond.vartok->hasKnownIntValue())
continue;
if (cond.true_values.empty() || cond.false_values.empty())
continue;
if (!isConstExpression(cond.vartok, settings->library, tokenlist.isCPP()))
continue;
f(cond, tok, scope);
}
}
}
}
void beforeCondition(TokenList& tokenlist,
const SymbolDatabase& symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings,
const std::set<const Scope*>& skippedFunctions) const {
traverseCondition(tokenlist, symboldatabase, settings, skippedFunctions, [&](const Condition& cond, Token* tok, const Scope*) {
if (cond.vartok->exprId() == 0)
return;
// If condition is known then don't propagate value
if (tok->hasKnownIntValue())
return;
Token* top = tok->astTop();
if (Token::Match(top, "%assign%"))
return;
if (Token::Match(cond.vartok->astParent(), "%assign%|++|--"))
return;
if (Token::simpleMatch(tok->astParent(), "?") && tok->astParent()->isExpandedMacro()) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok,
"variable '" + cond.vartok->expressionString() + "', condition is defined in macro");
return;
}
// if,macro => bailout
if (Token::simpleMatch(top->previous(), "if (") && top->previous()->isExpandedMacro()) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok,
"variable '" + cond.vartok->expressionString() + "', condition is defined in macro");
return;
}
std::list<ValueFlow::Value> values = cond.true_values;
if (cond.true_values != cond.false_values)
values.insert(values.end(), cond.false_values.cbegin(), cond.false_values.cend());
// extra logic for unsigned variables 'i>=1' => possible value can also be 0
if (Token::Match(tok, "<|>")) {
values.remove_if([](const ValueFlow::Value& v) {
if (v.isIntValue())
return v.intvalue != 0;
return false;
});
if (cond.vartok->valueType() && cond.vartok->valueType()->sign != ValueType::Sign::UNSIGNED)
return;
}
if (values.empty())
return;
// bailout: for/while-condition, variable is changed in while loop
if (Token::Match(top->previous(), "for|while (") && Token::simpleMatch(top->link(), ") {")) {
// Variable changed in 3rd for-expression
if (Token::simpleMatch(top->previous(), "for (")) {
if (top->astOperand2() && top->astOperand2()->astOperand2() &&
findExpressionChanged(
cond.vartok, top->astOperand2()->astOperand2(), top->link(), settings, tokenlist.isCPP())) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok,
"variable '" + cond.vartok->expressionString() + "' used in loop");
return;
}
}
// Variable changed in loop code
const Token* const start = top;
const Token* const block = top->link()->next();
const Token* const end = block->link();
if (findExpressionChanged(cond.vartok, start, end, settings, tokenlist.isCPP())) {
// If its reassigned in loop then analyze from the end
if (!Token::Match(tok, "%assign%|++|--") &&
findExpression(cond.vartok->exprId(), start, end, [&](const Token* tok2) {
return Token::Match(tok2->astParent(), "%assign%") && astIsLHS(tok2);
})) {
// Start at the end of the loop body
Token* bodyTok = top->link()->next();
reverse(bodyTok->link(), bodyTok, cond.vartok, values, tokenlist, settings);
}
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
tok,
"variable '" + cond.vartok->expressionString() + "' used in loop");
return;
}
}
Token* startTok = nullptr;
if (astIsRHS(tok))
startTok = tok->astParent();
else if (astIsLHS(tok))
startTok = previousBeforeAstLeftmostLeaf(tok->astParent());
if (!startTok)
startTok = tok->previous();
reverse(startTok, nullptr, cond.vartok, values, tokenlist, settings);
});
}
static Token* skipNotAndCasts(Token* tok, bool* inverted = nullptr)
{
for (; tok->astParent(); tok = tok->astParent()) {
if (Token::simpleMatch(tok->astParent(), "!")) {
if (inverted)
*inverted ^= true;
continue;
}
if (Token::Match(tok->astParent(), "==|!=")) {
const Token* sibling = tok->astSibling();
if (sibling->hasKnownIntValue() && (astIsBool(tok) || astIsBool(sibling))) {
const bool value = sibling->values().front().intvalue;
if (inverted)
*inverted ^= value == Token::simpleMatch(tok->astParent(), "!=");
continue;
}
}
if (tok->astParent()->isCast() && astIsBool(tok->astParent()))
continue;
return tok;
}
return tok;
}
static void fillFromPath(ProgramMemory& pm, const Token* top, MathLib::bigint path)
{
if (path < 1)
return;
visitAstNodes(top, [&](const Token* tok) {
const ValueFlow::Value* v = ValueFlow::findValue(tok->values(), nullptr, [&](const ValueFlow::Value& v) {
return v.path == path && isNonConditionalPossibleIntValue(v);
});
if (v == nullptr)
return ChildrenToVisit::op1_and_op2;
pm.setValue(tok, *v);
return ChildrenToVisit::op1_and_op2;
});
}
void afterCondition(TokenList& tokenlist,
const SymbolDatabase& symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings,
const std::set<const Scope*>& skippedFunctions) const {
traverseCondition(tokenlist, symboldatabase, settings, skippedFunctions, [&](const Condition& cond, Token* condTok, const Scope* scope) {
Token* top = condTok->astTop();
const MathLib::bigint path = cond.getPath();
const bool allowKnown = path == 0;
std::list<ValueFlow::Value> thenValues;
std::list<ValueFlow::Value> elseValues;
Token* ctx = cond.getContextAndValues(condTok, thenValues, elseValues);
if (Token::Match(ctx->astParent(), "%oror%|&&")) {
Token* parent = ctx->astParent();
if (astIsRHS(ctx) && astIsLHS(parent) && parent->astParent() &&
parent->str() == parent->astParent()->str())
parent = parent->astParent();
else if (!astIsLHS(ctx)) {
parent = nullptr;
}
if (parent) {
std::vector<Token*> nextExprs = {parent->astOperand2()};
if (astIsLHS(parent) && parent->astParent() && parent->astParent()->str() == parent->str()) {
nextExprs.push_back(parent->astParent()->astOperand2());
}
std::list<ValueFlow::Value> andValues;
std::list<ValueFlow::Value> orValues;
cond.getContextAndValues(condTok, andValues, orValues, true);
const std::string& op(parent->str());
std::list<ValueFlow::Value> values;
if (op == "&&")
values = andValues;
else if (op == "||")
values = orValues;
if (allowKnown && (Token::Match(condTok, "==|!=") || cond.isBool()))
changePossibleToKnown(values);
if (astIsFloat(cond.vartok, false) ||
(!cond.vartok->valueType() &&
std::all_of(values.cbegin(), values.cend(), [](const ValueFlow::Value& v) {
return v.isIntValue() || v.isFloatValue();
})))
values.remove_if([&](const ValueFlow::Value& v) {
return v.isImpossible();
});
for (Token* start:nextExprs) {
Analyzer::Result r = forward(start, cond.vartok, values, tokenlist, settings);
if (r.terminate != Analyzer::Terminate::None || r.action.isModified())
return;
}
}
}
{
const Token* tok2 = condTok;
std::string op;
bool mixedOperators = false;
while (tok2->astParent()) {
const Token* parent = tok2->astParent();
if (Token::Match(parent, "%oror%|&&")) {
if (op.empty()) {
op = parent->str();
} else if (op != parent->str()) {
mixedOperators = true;
break;
}
}
if (parent->str() == "!") {
op = (op == "&&" ? "||" : "&&");
}
tok2 = parent;
}
if (mixedOperators) {
return;
}
}
if (!top)
return;
if (top->previous()->isExpandedMacro()) {
for (std::list<ValueFlow::Value>* values : {&thenValues, &elseValues}) {
for (ValueFlow::Value& v : *values)
v.macro = true;
}
}
Token* condTop = ctx->astParent();
{
bool inverted2 = false;
while (Token::Match(condTop, "%oror%|&&")) {
Token* parent = skipNotAndCasts(condTop, &inverted2)->astParent();
if (!parent)
break;
condTop = parent;
}
if (inverted2)
std::swap(thenValues, elseValues);
}
if (!condTop)
return;
if (Token::simpleMatch(condTop, "?")) {
Token* colon = condTop->astOperand2();
forward(colon->astOperand1(), cond.vartok, thenValues, tokenlist, settings);
forward(colon->astOperand2(), cond.vartok, elseValues, tokenlist, settings);
// TODO: Handle after condition
return;
}
if (condTop != top && condTop->str() != ";")
return;
if (!Token::Match(top->previous(), "if|while|for ("))
return;
if (top->previous()->str() == "for") {
if (!Token::Match(condTok, "%comp%"))
return;
if (!Token::simpleMatch(condTok->astParent(), ";"))
return;
const Token* stepTok = getStepTok(top);
if (cond.vartok->varId() == 0)
return;
if (!cond.vartok->variable())
return;
if (!Token::Match(stepTok, "++|--"))
return;
std::set<ValueFlow::Value::Bound> bounds;
for (const ValueFlow::Value& v : thenValues) {
if (v.bound != ValueFlow::Value::Bound::Point && v.isImpossible())
continue;
bounds.insert(v.bound);
}
if (Token::simpleMatch(stepTok, "++") && bounds.count(ValueFlow::Value::Bound::Lower) > 0)
return;
if (Token::simpleMatch(stepTok, "--") && bounds.count(ValueFlow::Value::Bound::Upper) > 0)
return;
const Token* childTok = condTok->astOperand1();
if (!childTok)
childTok = condTok->astOperand2();
if (!childTok)
return;
if (childTok->varId() != cond.vartok->varId())
return;
const Token* startBlock = top->link()->next();
if (isVariableChanged(startBlock,
startBlock->link(),
cond.vartok->varId(),
cond.vartok->variable()->isGlobal(),
settings,
tokenlist.isCPP()))
return;
// Check if condition in for loop is always false
const Token* initTok = getInitTok(top);
ProgramMemory pm;
fillFromPath(pm, initTok, path);
fillFromPath(pm, condTok, path);
execute(initTok, pm, nullptr, nullptr);
MathLib::bigint result = 1;
execute(condTok, pm, &result, nullptr);
if (result == 0)
return;
// Remove condition since for condition is not redundant
for (std::list<ValueFlow::Value>* values : {&thenValues, &elseValues}) {
for (ValueFlow::Value& v : *values) {
v.condition = nullptr;
v.conditional = true;
}
}
}
bool deadBranch[] = {false, false};
// start token of conditional code
Token* startTokens[] = {nullptr, nullptr};
// 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;
int bailBlock = -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);
if (allowKnown)
valueFlowSetConditionToKnown(condTok, values, i == 0);
Analyzer::Result r = forward(startTokens[i], startTokens[i]->link(), cond.vartok, values, tokenlist, settings);
deadBranch[i] = r.terminate == Analyzer::Terminate::Escape;
if (r.action.isModified() && !deadBranch[i])
changeBlock = i;
if (r.terminate != Analyzer::Terminate::None && r.terminate != Analyzer::Terminate::Escape &&
r.terminate != Analyzer::Terminate::Modified)
bailBlock = i;
changeKnownToPossible(values);
}
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");
return;
}
if (bailBlock >= 0) {
if (settings->debugwarnings)
bailout(tokenlist,
errorLogger,
startTokens[bailBlock]->link(),
"valueFlowAfterCondition: bailing in conditional block");
return;
}
// After conditional code..
if (Token::simpleMatch(top->link(), ") {")) {
Token* after = top->link()->linkAt(1);
bool dead_if = deadBranch[0];
bool dead_else = deadBranch[1];
const Token* unknownFunction = nullptr;
if (condTok->astParent() && Token::Match(top->previous(), "while|for ("))
dead_if = !isBreakScope(after);
else if (!dead_if)
dead_if = isReturnScope(after, &settings->library, &unknownFunction);
if (!dead_if && unknownFunction) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope");
return;
}
if (Token::simpleMatch(after, "} else {")) {
after = after->linkAt(2);
unknownFunction = nullptr;
if (!dead_else)
dead_else = isReturnScope(after, &settings->library, &unknownFunction);
if (!dead_else && unknownFunction) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, unknownFunction, "possible noreturn scope");
return;
}
}
if (dead_if && dead_else)
return;
std::list<ValueFlow::Value> values;
if (dead_if) {
values = elseValues;
} else if (dead_else) {
values = thenValues;
} else {
std::copy_if(thenValues.cbegin(),
thenValues.cend(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isPossible));
std::copy_if(elseValues.cbegin(),
elseValues.cend(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isPossible));
}
if (values.empty())
return;
if (dead_if || dead_else) {
const Token* parent = condTok->astParent();
// Skip the not operator
while (Token::simpleMatch(parent, "!"))
parent = parent->astParent();
bool possible = false;
if (Token::Match(parent, "&&|%oror%")) {
const std::string& op(parent->str());
while (parent && parent->str() == op)
parent = parent->astParent();
if (Token::simpleMatch(parent, "!") || Token::simpleMatch(parent, "== false"))
possible = op == "||";
else
possible = op == "&&";
}
if (possible) {
values.remove_if(std::mem_fn(&ValueFlow::Value::isImpossible));
changeKnownToPossible(values);
} else if (allowKnown) {
valueFlowSetConditionToKnown(condTok, values, true);
valueFlowSetConditionToKnown(condTok, values, false);
}
}
if (values.empty())
return;
const bool isKnown = std::any_of(values.cbegin(), values.cend(), [&](const ValueFlow::Value& v) {
return v.isKnown() || v.isImpossible();
});
if (isKnown && isBreakOrContinueScope(after)) {
const Scope* loopScope = getLoopScope(cond.vartok);
if (loopScope) {
Analyzer::Result r = forward(after, loopScope->bodyEnd, cond.vartok, values, tokenlist, settings);
if (r.terminate != Analyzer::Terminate::None)
return;
if (r.action.isModified())
return;
Token* start = const_cast<Token*>(loopScope->bodyEnd);
if (Token::simpleMatch(start, "} while (")) {
start = start->tokAt(2);
forward(start, start->link(), cond.vartok, values, tokenlist, settings);
start = start->link();
}
values.remove_if(std::mem_fn(&ValueFlow::Value::isImpossible));
changeKnownToPossible(values);
}
}
forward(after, ValueFlow::getEndOfExprScope(cond.vartok, scope), cond.vartok, values, tokenlist, settings);
}
});
}
virtual ~ConditionHandler() = default;
ConditionHandler(const ConditionHandler&) = default;
protected:
ConditionHandler() = default;
};
static void valueFlowCondition(const ValuePtr<ConditionHandler>& handler,
TokenList& tokenlist,
SymbolDatabase& symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings,
const std::set<const Scope*>& skippedFunctions)
{
handler->beforeCondition(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions);
handler->afterCondition(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions);
}
struct SimpleConditionHandler : ConditionHandler {
std::vector<Condition> parse(const Token* tok, const Settings* /*settings*/) const override {
std::vector<Condition> conds;
parseCompareEachInt(tok, [&](const Token* vartok, ValueFlow::Value true_value, ValueFlow::Value false_value) {
if (vartok->hasKnownIntValue())
return;
if (vartok->str() == "=" && vartok->astOperand1() && vartok->astOperand2())
vartok = vartok->astOperand1();
Condition cond;
cond.true_values.push_back(std::move(true_value));
cond.false_values.push_back(std::move(false_value));
cond.vartok = vartok;
conds.push_back(std::move(cond));
});
if (!conds.empty())
return conds;
const Token* vartok = nullptr;
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 {};
Condition cond;
cond.true_values.emplace_back(tok, 0LL);
cond.false_values.emplace_back(tok, 0LL);
cond.vartok = vartok;
return {std::move(cond)};
}
};
struct IntegralInferModel : InferModel {
bool match(const ValueFlow::Value& value) const override {
return value.isIntValue();
}
ValueFlow::Value yield(MathLib::bigint value) const override
{
ValueFlow::Value result(value);
result.valueType = ValueFlow::Value::ValueType::INT;
result.setKnown();
return result;
}
};
ValuePtr<InferModel> ValueFlow::makeIntegralInferModel() {
return IntegralInferModel{};
}
static ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, MathLib::bigint val)
{
if (!varTok)
return ValueFlow::Value{};
if (varTok->hasKnownIntValue())
return ValueFlow::Value{};
std::vector<ValueFlow::Value> r = infer(IntegralInferModel{}, op, varTok->values(), val);
if (r.size() == 1 && r.front().isKnown())
return r.front();
return ValueFlow::Value{};
}
struct IteratorInferModel : InferModel {
virtual ValueFlow::Value::ValueType getType() const = 0;
bool match(const ValueFlow::Value& value) const override {
return value.valueType == getType();
}
ValueFlow::Value yield(MathLib::bigint value) const override
{
ValueFlow::Value result(value);
result.valueType = getType();
result.setKnown();
return result;
}
};
struct EndIteratorInferModel : IteratorInferModel {
ValueFlow::Value::ValueType getType() const override {
return ValueFlow::Value::ValueType::ITERATOR_END;
}
};
struct StartIteratorInferModel : IteratorInferModel {
ValueFlow::Value::ValueType getType() const override {
return ValueFlow::Value::ValueType::ITERATOR_END;
}
};
static bool isIntegralOnlyOperator(const Token* tok) {
return Token::Match(tok, "%|<<|>>|&|^|~|%or%");
}
static bool isIntegralOrPointer(const Token* tok)
{
if (!tok)
return false;
if (astIsIntegral(tok, false))
return true;
if (astIsPointer(tok))
return true;
if (Token::Match(tok, "NULL|nullptr"))
return true;
if (tok->valueType())
return false;
// These operators only work on integers
if (isIntegralOnlyOperator(tok))
return true;
if (isIntegralOnlyOperator(tok->astParent()))
return true;
if (Token::Match(tok, "+|-|*|/") && tok->isBinaryOp())
return isIntegralOrPointer(tok->astOperand1()) && isIntegralOrPointer(tok->astOperand2());
return false;
}
static void valueFlowInferCondition(TokenList& tokenlist,
const Settings* settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (!tok->astParent())
continue;
if (tok->hasKnownIntValue())
continue;
if (Token::Match(tok, "%comp%|-") && tok->astOperand1() && tok->astOperand2()) {
if (astIsIterator(tok->astOperand1()) || astIsIterator(tok->astOperand2())) {
static const std::array<ValuePtr<InferModel>, 2> iteratorModels = {EndIteratorInferModel{},
StartIteratorInferModel{}};
for (const ValuePtr<InferModel>& model : iteratorModels) {
std::vector<ValueFlow::Value> result =
infer(model, tok->str(), tok->astOperand1()->values(), tok->astOperand2()->values());
for (ValueFlow::Value value : result) {
value.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(tok, std::move(value), settings);
}
}
} else if (isIntegralOrPointer(tok->astOperand1()) && isIntegralOrPointer(tok->astOperand2())) {
std::vector<ValueFlow::Value> result =
infer(IntegralInferModel{}, tok->str(), tok->astOperand1()->values(), tok->astOperand2()->values());
for (ValueFlow::Value& value : result) {
setTokenValue(tok, std::move(value), settings);
}
}
} else if (Token::Match(tok->astParent(), "?|&&|!|%oror%") ||
Token::Match(tok->astParent()->previous(), "if|while (") ||
(astIsPointer(tok) && isUsedAsBool(tok, settings))) {
std::vector<ValueFlow::Value> result = infer(IntegralInferModel{}, "!=", tok->values(), 0);
if (result.size() != 1)
continue;
ValueFlow::Value value = result.front();
setTokenValue(tok, std::move(value), settings);
}
}
}
struct SymbolicConditionHandler : SimpleConditionHandler {
static bool isNegatedBool(const Token* tok)
{
if (!Token::simpleMatch(tok, "!"))
return false;
return (astIsBool(tok->astOperand1()));
}
static const Token* skipNot(const Token* tok)
{
if (!Token::simpleMatch(tok, "!"))
return tok;
return tok->astOperand1();
}
std::vector<Condition> parse(const Token* tok, const Settings* settings) const override
{
if (!Token::Match(tok, "%comp%"))
return {};
if (tok->hasKnownIntValue())
return {};
if (!tok->astOperand1() || tok->astOperand1()->hasKnownIntValue() || tok->astOperand1()->isLiteral())
return {};
if (!tok->astOperand2() || tok->astOperand2()->hasKnownIntValue() || tok->astOperand2()->isLiteral())
return {};
if (!isConstExpression(tok, settings->library, true))
return {};
std::vector<Condition> result;
auto addCond = [&](const Token* lhsTok, const Token* rhsTok, bool inverted) {
for (int i = 0; i < 2; i++) {
const bool lhs = i == 0;
const Token* vartok = lhs ? lhsTok : rhsTok;
const Token* valuetok = lhs ? rhsTok : lhsTok;
if (valuetok->exprId() == 0)
continue;
if (valuetok->hasKnownSymbolicValue(vartok))
continue;
if (vartok->hasKnownSymbolicValue(valuetok))
continue;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
setConditionalValues(tok, !lhs, 0, true_value, false_value);
setSymbolic(true_value, valuetok);
setSymbolic(false_value, valuetok);
Condition cond;
cond.true_values = {std::move(true_value)};
cond.false_values = {std::move(false_value)};
cond.vartok = vartok;
cond.inverted = inverted;
result.push_back(std::move(cond));
}
};
addCond(tok->astOperand1(), tok->astOperand2(), false);
if (Token::Match(tok, "==|!=") && (isNegatedBool(tok->astOperand1()) || isNegatedBool(tok->astOperand2()))) {
const Token* lhsTok = skipNot(tok->astOperand1());
const Token* rhsTok = skipNot(tok->astOperand2());
addCond(lhsTok, rhsTok, !(isNegatedBool(tok->astOperand1()) && isNegatedBool(tok->astOperand2())));
}
return result;
}
};
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);
}
if (memory1)
memory1->swap(startMemory);
if (!error) {
if (memory2)
memory2->swap(endMemory);
if (memoryAfter)
memoryAfter->swap(programMemory);
}
return true;
}
static void valueFlowForLoopSimplify(Token* const bodyStart,
const Token* expr,
bool globalvar,
const MathLib::bigint value,
const TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings* settings)
{
// TODO: Refactor this to use arbitrary expressions
assert(expr->varId() > 0);
const Token * const bodyEnd = bodyStart->link();
// Is variable modified inside for loop
if (isVariableChanged(bodyStart, bodyEnd, expr->varId(), globalvar, settings, tokenlist.isCPP()))
return;
for (Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) {
if (tok2->varId() == expr->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, std::move(value1), settings);
}
if (Token::Match(tok2, "%oror%|&&")) {
const ProgramMemory programMemory(getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings));
if ((tok2->str() == "&&" && !conditionIsTrue(tok2->astOperand1(), programMemory)) ||
(tok2->str() == "||" && !conditionIsFalse(tok2->astOperand1(), programMemory))) {
// Skip second expression..
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);
}
}
}
const Token* vartok = expr;
const Token* rml = nextAfterAstRightmostLeaf(vartok);
if (rml)
vartok = rml->str() == "]" ? rml : rml->previous();
if (vartok->str() == "]" && vartok->link()->previous())
vartok = vartok->link()->previous();
if ((tok2->str() == "&&" &&
conditionIsFalse(tok2->astOperand1(),
getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings))) ||
(tok2->str() == "||" &&
conditionIsTrue(tok2->astOperand1(),
getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings))))
break;
if (Token::simpleMatch(tok2, ") {")) {
if (vartok->varId() && Token::findmatch(tok2->link(), "%varid%", tok2, vartok->varId())) {
if (Token::findmatch(tok2, "continue|break|return", tok2->linkAt(1), vartok->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), vartok->varId())) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop variable bailout on conditional continue|break|return");
break;
}
tok2 = tok2->linkAt(2);
}
}
else {
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, const TokenList& tokenlist, 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);
if (blockTok != endToken) {
ValueFlow::Value v{num};
v.errorPath.emplace_back(fortok,"After for loop, " + var->name() + " has value " + v.infoString());
valueFlowForward(blockTok->next(), endToken, vartok, v, tokenlist, settings);
}
}
static void valueFlowForLoop(TokenList &tokenlist, const 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;
const Token* vartok = Token::findmatch(tok, "%varid%", bodyStart, varid);
if (executeBody && vartok) {
std::list<ValueFlow::Value> initValues;
initValues.emplace_back(initValue, ValueFlow::Value::Bound::Lower);
initValues.push_back(ValueFlow::asImpossible(initValues.back()));
Analyzer::Result result = valueFlowForward(bodyStart, bodyStart->link(), vartok, initValues, tokenlist, settings);
if (!result.action.isModified()) {
std::list<ValueFlow::Value> lastValues;
lastValues.emplace_back(lastValue, ValueFlow::Value::Bound::Upper);
lastValues.back().conditional = true;
lastValues.push_back(ValueFlow::asImpossible(lastValues.back()));
if (stepValue != 1)
lastValues.pop_front();
valueFlowForward(bodyStart, bodyStart->link(), vartok, lastValues, tokenlist, settings);
}
}
const MathLib::bigint afterValue = executeBody ? lastValue + stepValue : initValue;
valueFlowForLoopSimplifyAfter(tok, varid, afterValue, tokenlist, settings);
} else {
ProgramMemory mem1, mem2, memAfter;
if (valueFlowForLoop2(tok, &mem1, &mem2, &memAfter)) {
for (const auto& p : mem1) {
if (!p.second.isIntValue())
continue;
if (p.second.isImpossible())
continue;
if (p.first.tok->varId() == 0)
continue;
valueFlowForLoopSimplify(bodyStart, p.first.tok, false, p.second.intvalue, tokenlist, errorLogger, settings);
}
for (const auto& p : mem2) {
if (!p.second.isIntValue())
continue;
if (p.second.isImpossible())
continue;
if (p.first.tok->varId() == 0)
continue;
valueFlowForLoopSimplify(bodyStart, p.first.tok, false, p.second.intvalue, tokenlist, errorLogger, settings);
}
for (const auto& p : memAfter) {
if (!p.second.isIntValue())
continue;
if (p.second.isImpossible())
continue;
if (p.first.tok->varId() == 0)
continue;
valueFlowForLoopSimplifyAfter(tok, p.first.getExpressionId(), p.second.intvalue, tokenlist, settings);
}
}
}
}
}
struct MultiValueFlowAnalyzer : ValueFlowAnalyzer {
std::unordered_map<nonneg int, ValueFlow::Value> values;
std::unordered_map<nonneg int, const Variable*> vars;
MultiValueFlowAnalyzer(const std::unordered_map<const Variable*, ValueFlow::Value>& args, const TokenList& t, const Settings* set)
: ValueFlowAnalyzer(t, set) {
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;
}
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;
}
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;
}
void makeConditional() override {
for (auto&& p:values) {
p.second.conditional = true;
}
}
void addErrorPath(const Token* tok, const std::string& s) override {
for (auto&& p:values) {
p.second.errorPath.emplace_back(tok, s);
}
}
bool isAlias(const Token* tok, bool& inconclusive) const override {
const auto range = SelectValueFromVarIdMapRange(&values);
for (const auto& p:getVars()) {
nonneg int const varid = p.first;
const Variable* var = p.second;
if (tok->varId() == varid)
return true;
if (isAliasOf(var, tok, varid, range, &inconclusive))
return true;
}
return false;
}
bool lowerToPossible() override {
for (auto&& p:values) {
if (p.second.isImpossible())
return false;
p.second.changeKnownToPossible();
}
return true;
}
bool lowerToInconclusive() override {
for (auto&& p:values) {
if (p.second.isImpossible())
return false;
p.second.setInconclusive();
}
return true;
}
bool isConditional() const override {
for (auto&& p:values) {
if (p.second.conditional)
return true;
if (p.second.condition)
return !p.second.isImpossible();
}
return false;
}
bool stopOnCondition(const Token* /*condTok*/) const override {
// TODO fix false negatives
return true; // isConditional();
}
bool updateScope(const Token* endBlock, bool /*modified*/) const override {
const Scope* scope = endBlock->scope();
if (!scope)
return false;
if (scope->type == Scope::eLambda) {
return std::all_of(values.cbegin(), values.cend(), [](const std::pair<nonneg int, ValueFlow::Value>& p) {
return p.second.isLifetimeValue();
});
}
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.cbegin(), values.cend(), 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().cbegin(), getVars().cend(), std::inserter(varids, varids.begin()), SelectMapKeys{});
return bifurcate(condTok, varids, getSettings());
}
return false;
}
bool match(const Token* tok) const override {
return values.count(tok->varId()) > 0;
}
ProgramState getProgramState() const override {
ProgramState ps;
for (const auto& p : values) {
const Variable* var = vars.at(p.first);
if (!var)
continue;
ps[var->nameToken()] = p.second;
}
return ps;
}
};
template<class Key, class F>
static bool productParams(const Settings* settings, const std::unordered_map<Key, std::list<ValueFlow::Value>>& vars, F f)
{
using Args = std::vector<std::unordered_map<Key, 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();
}
bool bail = false;
int max = 8;
if (settings)
max = settings->performanceValueFlowMaxSubFunctionArgs;
for (const auto& p:vars) {
if (args.size() > max) {
bail = true;
break;
}
if (p.second.empty())
continue;
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.first == p.first)
continue;
if (q.second.path == 0)
continue;
if (q.second.path != value.path)
return;
}
}
arg[p.first] = value;
new_args.push_back(std::move(arg));
}
std::copy(new_args.cbegin(), new_args.cend(), std::back_inserter(args));
});
}
if (args.size() > max) {
bail = true;
args.resize(max);
}
for (const auto& arg:args) {
if (arg.empty())
continue;
// Make sure all arguments are the same path
const MathLib::bigint path = arg.cbegin()->second.path;
if (std::any_of(arg.cbegin(), arg.cend(), [&](const std::pair<Key, ValueFlow::Value>& p) {
return p.second.path != path;
}))
continue;
f(arg);
}
return !bail;
}
static void valueFlowInjectParameter(TokenList& tokenlist,
ErrorLogger* errorLogger,
const Settings& settings,
const Scope* functionScope,
const std::unordered_map<const Variable*, std::list<ValueFlow::Value>>& vars)
{
const bool r = productParams(&settings, vars, [&](const std::unordered_map<const Variable*, ValueFlow::Value>& arg) {
MultiValueFlowAnalyzer a(arg, tokenlist, &settings);
valueFlowGenericForward(const_cast<Token*>(functionScope->bodyStart), functionScope->bodyEnd, a, settings);
});
if (!r) {
std::string fname = "<unknown>";
if (const Function* f = functionScope->function)
fname = f->name();
if (settings.debugwarnings)
bailout(tokenlist, errorLogger, functionScope->bodyStart, "Too many argument passed to " + fname);
}
}
static void valueFlowInjectParameter(const TokenList& tokenlist,
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 nonneg int varid2 = arg->declarationId();
if (!varid2)
return;
valueFlowForward(const_cast<Token*>(functionScope->bodyStart->next()),
functionScope->bodyEnd,
arg->nameToken(),
argvalues,
tokenlist,
settings);
}
static void valueFlowSwitchVariable(const TokenList &tokenlist, const 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 (const 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::toBigNumber(tok->next()->str()));
values.back().condition = tok;
values.back().errorPath.emplace_back(tok, "case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here.");
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::toBigNumber(tok->next()->str()));
values.back().condition = tok;
values.back().errorPath.emplace_back(tok, "case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here.");
}
for (std::list<ValueFlow::Value>::const_iterator val = values.cbegin(); val != values.cend(); ++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 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::unordered_map<nonneg int, std::list<ValueFlow::Value>> argValues;
int argn = 1;
for (const Token *argtok : getArguments(tok->previous())) {
argValues[argn] = getFunctionArgumentValues(argtok);
argn++;
}
if (returnValue.find("arg") != std::string::npos && argValues.empty())
return;
productParams(settings, argValues, [&](const std::unordered_map<nonneg int, ValueFlow::Value>& arg) {
ValueFlow::Value value = evaluateLibraryFunction(arg, returnValue, settings);
if (value.isUninitValue())
return;
ValueFlow::Value::ValueKind kind = ValueFlow::Value::ValueKind::Known;
for (auto&& p : arg) {
if (p.second.isPossible())
kind = p.second.valueKind;
if (p.second.isInconclusive()) {
kind = p.second.valueKind;
break;
}
}
if (value.isImpossible() && kind != ValueFlow::Value::ValueKind::Known)
return;
if (!value.isImpossible())
value.valueKind = kind;
setTokenValue(tok, std::move(value), settings);
});
}
template<class Iterator>
struct IteratorRange
{
Iterator mBegin;
Iterator mEnd;
Iterator begin() const {
return mBegin;
}
Iterator end() const {
return mEnd;
}
};
template<class Iterator>
static IteratorRange<Iterator> MakeIteratorRange(Iterator start, Iterator last)
{
return {start, last};
}
static void valueFlowSubFunction(TokenList& tokenlist, SymbolDatabase& symboldatabase, ErrorLogger* errorLogger, const Settings& settings)
{
int id = 0;
for (const Scope* scope : MakeIteratorRange(symboldatabase.functionScopes.crbegin(), symboldatabase.functionScopes.crend())) {
const Function* function = scope->function;
if (!function)
continue;
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (tok->isKeyword() || !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));
// Remove non-local lifetimes
argvalues.remove_if([](const ValueFlow::Value& v) {
if (v.isLifetimeValue())
return !v.isLocalLifetimeValue() && !v.isSubFunctionLifetimeValue();
return false;
});
// Remove uninit values if argument is passed by value
if (argtok->variable() && !argtok->variable()->isPointer() && argvalues.size() == 1 && argvalues.front().isUninitValue()) {
if (CheckUninitVar::isVariableUsage(argtok, settings.library, false, CheckUninitVar::Alloc::NO_ALLOC, 0))
continue;
}
if (argvalues.empty())
continue;
// Error path..
for (ValueFlow::Value &v : argvalues) {
const std::string nr = std::to_string(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 % 256;
// 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(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, 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(std::move(v));
}
if (!argvalues.empty())
valueFlowInjectParameter(tokenlist, settings, var, scope, argvalues);
}
}
}
}
static const ValueFlow::Value* getKnownValueFromToken(const Token* tok)
{
if (!tok)
return nullptr;
auto it = std::find_if(tok->values().begin(), tok->values().end(), [&](const ValueFlow::Value& v) {
return (v.isIntValue() || v.isContainerSizeValue() || v.isFloatValue()) && v.isKnown();
});
if (it == tok->values().end())
return nullptr;
return std::addressof(*it);
}
static const ValueFlow::Value* getKnownValueFromTokens(const std::vector<const Token*>& toks)
{
if (toks.empty())
return nullptr;
const ValueFlow::Value* result = getKnownValueFromToken(toks.front());
if (!result)
return nullptr;
if (!std::all_of(std::next(toks.begin()), toks.end(), [&](const Token* tok) {
return std::any_of(tok->values().begin(), tok->values().end(), [&](const ValueFlow::Value& v) {
return v.equalValue(*result) && v.valueKind == result->valueKind;
});
}))
return nullptr;
return result;
}
static void setFunctionReturnValue(const Function* f, Token* tok, ValueFlow::Value v, const Settings* settings)
{
if (f->hasVirtualSpecifier()) {
if (v.isImpossible())
return;
v.setPossible();
} else if (!v.isImpossible()) {
v.setKnown();
}
v.errorPath.emplace_back(tok, "Calling function '" + f->name() + "' returns " + v.toString());
setTokenValue(tok, std::move(v), settings);
}
static void valueFlowFunctionReturn(TokenList &tokenlist, ErrorLogger *errorLogger, const Settings* settings)
{
for (Token *tok = tokenlist.back(); tok; tok = tok->previous()) {
if (tok->str() != "(" || !tok->astOperand1())
continue;
const Function* function = nullptr;
if (Token::Match(tok->previous(), "%name% ("))
function = tok->previous()->function();
else
function = tok->astOperand1()->function();
if (!function)
continue;
// TODO: Check if member variable is a pointer or reference
if (function->isImplicitlyVirtual() && !function->hasFinalSpecifier())
continue;
if (tok->hasKnownValue())
continue;
std::vector<const Token*> returns = Function::findReturns(function);
if (returns.empty())
continue;
if (const ValueFlow::Value* v = getKnownValueFromTokens(returns)) {
setFunctionReturnValue(function, tok, *v, settings);
continue;
}
// Arguments..
std::vector<const Token*> arguments = getArguments(tok);
ProgramMemory programMemory;
for (std::size_t i = 0; i < arguments.size(); ++i) {
const Variable * const arg = function->getArgumentVar(i);
if (!arg) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "function return; unhandled argument type");
programMemory.clear();
break;
}
const ValueFlow::Value* v = getKnownValueFromToken(arguments[i]);
if (!v)
continue;
programMemory.setValue(arg->nameToken(), *v);
}
if (programMemory.empty() && !arguments.empty())
continue;
std::vector<ValueFlow::Value> values = execute(function->functionScope, programMemory, settings);
for (const ValueFlow::Value& v : values) {
if (v.isUninitValue())
continue;
setFunctionReturnValue(function, tok, v, settings);
}
}
}
static bool needsInitialization(const Variable* var, bool cpp)
{
if (!var)
return false;
if (var->hasDefault())
return false;
if (var->isPointer())
return true;
if (var->type() && var->type()->isUnionType())
return false;
if (!cpp)
return true;
if (var->type() && var->type()->needInitialization == Type::NeedInitialization::True)
return true;
if (var->valueType()) {
if (var->valueType()->isPrimitive())
return true;
if (var->valueType()->type == ValueType::Type::POD)
return true;
if (var->valueType()->type == ValueType::Type::ITERATOR)
return true;
}
return false;
}
static void addToErrorPath(ValueFlow::Value& value, const ValueFlow::Value& from)
{
std::unordered_set<const Token*> locations;
std::transform(value.errorPath.cbegin(),
value.errorPath.cend(),
std::inserter(locations, locations.begin()),
[](const ErrorPathItem& e) {
return e.first;
});
if (from.condition && !value.condition)
value.condition = from.condition;
std::copy_if(from.errorPath.cbegin(),
from.errorPath.cend(),
std::back_inserter(value.errorPath),
[&](const ErrorPathItem& e) {
return locations.insert(e.first).second;
});
}
static std::vector<Token*> findAllUsages(const Variable* var,
Token* start, // cppcheck-suppress constParameterPointer // FP
const Library* library)
{
// std::vector<Token*> result;
const Scope* scope = var->scope();
if (!scope)
return {};
return findTokensSkipDeadCode(library, start, scope->bodyEnd, [&](const Token* tok) {
return tok->varId() == var->declarationId();
});
}
static Token* findStartToken(const Variable* var, Token* start, const Library* library)
{
std::vector<Token*> uses = findAllUsages(var, start, library);
if (uses.empty())
return start;
Token* first = uses.front();
if (Token::findmatch(start, "goto|asm|setjmp|longjmp", first))
return start;
if (first != var->nameToken()) {
// if this is lhs in assignment then set first to the first token in LHS expression
Token* temp = first;
while (Token::Match(temp->astParent(), "[&*(]") && precedes(temp->astParent(), temp))
temp = temp->astParent();
if (Token::simpleMatch(temp->astParent(), "=") && precedes(temp, temp->astParent()))
first = temp;
}
// If there is only one usage
if (uses.size() == 1)
return first->previous();
const Scope* scope = first->scope();
// If first usage is in variable scope
if (scope == var->scope()) {
bool isLoopExpression = false;
for (const Token* parent = first; parent; parent = parent->astParent()) {
if (Token::simpleMatch(parent->astParent(), ";") &&
Token::simpleMatch(parent->astParent()->astParent(), ";") &&
Token::simpleMatch(parent->astParent()->astParent()->astParent(), "(") &&
Token::simpleMatch(parent->astParent()->astParent()->astParent()->astOperand1(), "for (") &&
parent == parent->astParent()->astParent()->astParent()->astOperand2()->astOperand2()->astOperand2()) {
isLoopExpression = true;
}
}
return isLoopExpression ? start : first->previous();
}
// If all uses are in the same scope
if (std::all_of(uses.begin() + 1, uses.end(), [&](const Token* tok) {
return tok->scope() == scope;
}))
return first->previous();
// Compute the outer scope
while (scope && scope->nestedIn != var->scope())
scope = scope->nestedIn;
if (!scope)
return start;
Token* tok = const_cast<Token*>(scope->bodyStart);
if (!tok)
return start;
if (Token::simpleMatch(tok->tokAt(-2), "} else {"))
tok = tok->linkAt(-2);
if (Token::simpleMatch(tok->previous(), ") {"))
return tok->linkAt(-1)->previous();
return tok;
}
static void valueFlowUninit(TokenList& tokenlist, const Settings* settings)
{
for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
if (!tok->scope()->isExecutable())
continue;
if (!Token::Match(tok, "%var% ;|["))
continue;
const Variable* var = tok->variable();
if (!var)
continue;
if (var->nameToken() != tok || var->isInit())
continue;
if (!needsInitialization(var, tokenlist.isCPP()))
continue;
if (!var->isLocal() || var->isStatic() || var->isExtern() || var->isReference() || var->isThrow())
continue;
ValueFlow::Value uninitValue;
uninitValue.setKnown();
uninitValue.valueType = ValueFlow::Value::ValueType::UNINIT;
uninitValue.tokvalue = tok;
if (var->isArray())
uninitValue.indirect = var->dimensions().size();
bool partial = false;
Token* start = findStartToken(var, tok->next(), &settings->library);
std::map<Token*, ValueFlow::Value> partialReads;
if (const Scope* scope = var->typeScope()) {
if (Token::findsimplematch(scope->bodyStart, "union", scope->bodyEnd))
continue;
for (const Variable& memVar : scope->varlist) {
if (!memVar.isPublic())
continue;
// Skip array since we can't track partial initialization from nested subexpressions
if (memVar.isArray())
continue;
if (!needsInitialization(&memVar, tokenlist.isCPP())) {
partial = true;
continue;
}
MemberExpressionAnalyzer analyzer(memVar.nameToken()->str(), tok, uninitValue, tokenlist, settings);
valueFlowGenericForward(start, tok->scope()->bodyEnd, analyzer, *settings);
for (auto&& p : *analyzer.partialReads) {
Token* tok2 = p.first;
const ValueFlow::Value& v = p.second;
// Try to insert into map
auto pp = partialReads.insert(std::make_pair(tok2, v));
ValueFlow::Value& v2 = pp.first->second;
const bool inserted = pp.second;
// Merge the two values if it is already in map
if (!inserted) {
if (v.valueType != v2.valueType)
continue;
addToErrorPath(v2, v);
}
v2.subexpressions.push_back(memVar.nameToken()->str());
}
}
}
for (auto&& p : partialReads) {
Token* tok2 = p.first;
ValueFlow::Value& v = p.second;
setTokenValue(tok2, std::move(v), settings);
}
if (partial)
continue;
valueFlowForward(start, tok->scope()->bodyEnd, var->nameToken(), uninitValue, tokenlist, settings);
}
}
static bool isContainerSizeChanged(const Token* expr,
const Token* start,
const Token* end,
int indirect,
const Settings* settings = nullptr,
int depth = 20);
static bool isContainerSizeChangedByFunction(const Token* tok,
int indirect,
const Settings* settings = nullptr,
int depth = 20)
{
if (!tok->valueType())
return false;
if (!astIsContainer(tok))
return false;
// If we are accessing an element then we are not changing the container size
if (Token::Match(tok, "%name% . %name% (")) {
const Library::Container::Yield yield = getLibraryContainer(tok)->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 && !fun->isImplicitlyVirtual()) {
const Variable *arg = fun->getArgumentVar(narg);
if (arg) {
const bool isPointer = addressOf || indirect > 0;
if (!arg->isReference() && !isPointer)
return false;
if (!isPointer && 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->nameToken(),
scope->bodyStart,
scope->bodyEnd,
addressOf ? indirect + 1 : indirect,
settings,
depth - 1);
}
// Don't know => Safe guess
return true;
}
}
bool inconclusive = false;
const bool isChanged = isVariableChangedByFunctionCall(tok, indirect, settings, &inconclusive);
return (isChanged || inconclusive);
}
struct ContainerExpressionAnalyzer : ExpressionAnalyzer {
ContainerExpressionAnalyzer(const Token* expr, ValueFlow::Value val, const TokenList& t, const Settings* s)
: ExpressionAnalyzer(expr, std::move(val), t, s)
{}
bool match(const Token* tok) const override {
return tok->exprId() == expr->exprId() || (astIsIterator(tok) && isAliasOf(tok, expr->exprId()));
}
Action isWritable(const Token* tok, Direction /*d*/) const override
{
if (astIsIterator(tok))
return Action::None;
if (!getValue(tok))
return Action::None;
if (!tok->valueType())
return Action::None;
if (!astIsContainer(tok))
return Action::None;
const Token* parent = tok->astParent();
const Library::Container* container = getLibraryContainer(tok);
if (container->stdStringLike && Token::simpleMatch(parent, "+=") && astIsLHS(tok) && parent->astOperand2()) {
const Token* rhs = parent->astOperand2();
if (rhs->tokType() == Token::eString)
return Action::Read | Action::Write | Action::Incremental;
const Library::Container* rhsContainer = getLibraryContainer(rhs);
if (rhsContainer && rhsContainer->stdStringLike) {
if (std::any_of(rhs->values().cbegin(), rhs->values().cend(), [&](const ValueFlow::Value &rhsval) {
return rhsval.isKnown() && rhsval.isContainerSizeValue();
}))
return Action::Read | Action::Write | Action::Incremental;
}
} else if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (")) {
const Library::Container::Action action = container->getAction(tok->astParent()->strAt(1));
if (action == Library::Container::Action::PUSH || action == Library::Container::Action::POP) {
std::vector<const Token*> args = getArguments(tok->tokAt(3));
if (args.size() < 2)
return Action::Read | Action::Write | Action::Incremental;
}
}
return Action::None;
}
void writeValue(ValueFlow::Value* val, const Token* tok, Direction d) const override {
if (!val)
return;
if (!tok->astParent())
return;
if (!tok->valueType())
return;
if (!astIsContainer(tok))
return;
const Token* parent = tok->astParent();
const Library::Container* container = getLibraryContainer(tok);
int n = 0;
if (container->stdStringLike && Token::simpleMatch(parent, "+=") && parent->astOperand2()) {
const Token* rhs = parent->astOperand2();
const Library::Container* rhsContainer = getLibraryContainer(rhs);
if (rhs->tokType() == Token::eString)
n = Token::getStrLength(rhs);
else if (rhsContainer && rhsContainer->stdStringLike) {
auto it = std::find_if(rhs->values().begin(), rhs->values().end(), [&](const ValueFlow::Value& rhsval) {
return rhsval.isKnown() && rhsval.isContainerSizeValue();
});
if (it != rhs->values().end())
n = it->intvalue;
}
} else if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (")) {
const Library::Container::Action action = container->getAction(tok->astParent()->strAt(1));
if (action == Library::Container::Action::PUSH)
n = 1;
if (action == Library::Container::Action::POP)
n = -1;
}
if (d == Direction::Reverse)
val->intvalue -= n;
else
val->intvalue += n;
}
int getIndirect(const Token* tok) const override
{
if (tok->valueType()) {
return tok->valueType()->pointer;
}
return ValueFlowAnalyzer::getIndirect(tok);
}
Action isModified(const Token* tok) const override {
Action read = Action::Read;
// An iterator won't 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 (astIsContainer(tok) && ValueFlow::isContainerSizeChanged(tok, getIndirect(tok), getSettings()))
return read | Action::Invalid;
return read;
}
};
static const Token* parseBinaryIntOp(const Token* expr,
const std::function<std::vector<MathLib::bigint>(const Token*)>& eval,
MathLib::bigint& known)
{
if (!expr)
return nullptr;
if (!expr->astOperand1() || !expr->astOperand2())
return nullptr;
if (expr->astOperand1()->exprId() == 0 && expr->astOperand2()->exprId() == 0)
return nullptr;
std::vector<MathLib::bigint> x1 = eval(expr->astOperand1());
std::vector<MathLib::bigint> x2 = eval(expr->astOperand2());
if (expr->astOperand1()->exprId() == 0 && x1.empty())
return nullptr;
if (expr->astOperand2()->exprId() == 0 && x2.empty())
return nullptr;
const Token* varTok = nullptr;
if (!x1.empty() && x2.empty()) {
varTok = expr->astOperand2();
known = x1.front();
} else if (x1.empty() && !x2.empty()) {
varTok = expr->astOperand1();
known = x2.front();
}
return varTok;
}
const Token* ValueFlow::solveExprValue(const Token* expr,
const std::function<std::vector<MathLib::bigint>(const Token*)>& eval,
ValueFlow::Value& value)
{
if (!value.isIntValue() && !value.isIteratorValue() && !value.isSymbolicValue())
return expr;
if (value.isSymbolicValue() && !Token::Match(expr, "+|-"))
return expr;
MathLib::bigint intval;
const Token* binaryTok = parseBinaryIntOp(expr, eval, intval);
const bool rhs = astIsRHS(binaryTok);
// If its on the rhs, then -1 multiplication is needed, which is not possible with simple delta analysis used currently for symbolic values
if (value.isSymbolicValue() && rhs && Token::simpleMatch(expr, "-"))
return expr;
if (binaryTok && expr->str().size() == 1) {
switch (expr->str()[0]) {
case '+': {
value.intvalue -= intval;
return ValueFlow::solveExprValue(binaryTok, eval, value);
}
case '-': {
if (rhs)
value.intvalue = intval - value.intvalue;
else
value.intvalue += intval;
return ValueFlow::solveExprValue(binaryTok, eval, value);
}
case '*': {
if (intval == 0)
break;
value.intvalue /= intval;
return ValueFlow::solveExprValue(binaryTok, eval, value);
}
case '^': {
value.intvalue ^= intval;
return ValueFlow::solveExprValue(binaryTok, eval, value);
}
}
}
return expr;
}
static const Token* solveExprValue(const Token* expr, ValueFlow::Value& value)
{
return ValueFlow::solveExprValue(
expr,
[](const Token* tok) -> std::vector<MathLib::bigint> {
if (tok->hasKnownIntValue())
return {tok->values().front().intvalue};
return {};
},
value);
}
static ValuePtr<Analyzer> makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings)
{
if (value.isContainerSizeValue())
return ContainerExpressionAnalyzer(exprTok, std::move(value), tokenlist, settings);
const Token* expr = solveExprValue(exprTok, value);
return ExpressionAnalyzer(expr, std::move(value), tokenlist, settings);
}
static ValuePtr<Analyzer> makeReverseAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList& tokenlist, const Settings* settings)
{
if (value.isContainerSizeValue())
return ContainerExpressionAnalyzer(exprTok, std::move(value), tokenlist, settings);
return ExpressionAnalyzer(exprTok, std::move(value), tokenlist, settings);
}
bool ValueFlow::isContainerSizeChanged(const Token* tok, int indirect, const Settings* settings, int depth)
{
if (!tok)
return false;
if (!tok->valueType() || !tok->valueType()->container)
return true;
if (astIsLHS(tok) && Token::Match(tok->astParent(), "%assign%|<<"))
return true;
const Library::Container* container = tok->valueType()->container;
if (astIsLHS(tok) && Token::simpleMatch(tok->astParent(), "["))
return container->stdAssociativeLike;
const Library::Container::Action action = astContainerAction(tok);
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:
return true;
case Library::Container::Action::NO_ACTION:
// Is this an unknown member function call?
if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (")) {
const Library::Container::Yield yield = astContainerYield(tok);
return yield == Library::Container::Yield::NO_YIELD;
}
break;
case Library::Container::Action::FIND:
case Library::Container::Action::FIND_CONST:
case Library::Container::Action::CHANGE_CONTENT:
case Library::Container::Action::CHANGE_INTERNAL:
break;
}
return isContainerSizeChangedByFunction(tok, indirect, settings, depth);
}
static bool isContainerSizeChanged(const Token* expr,
const Token* start,
const Token* end,
int indirect,
const Settings* settings,
int depth)
{
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->exprId() != expr->exprId() && !isAliasOf(tok, expr))
continue;
if (ValueFlow::isContainerSizeChanged(tok, indirect, settings, 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 (!astIsSmartPointer(tok))
continue;
if (tok->variable() && Token::Match(tok, "%var% (|{|;")) {
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();
const 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% ;")) {
ValueFlow::Value v(0);
v.setKnown();
valueFlowForwardAssign(tok, var, {std::move(v)}, false, true, tokenlist, errorLogger, settings);
}
}
} else if (astIsLHS(tok) && Token::Match(tok->astParent(), ". %name% (") &&
tok->astParent()->originalName() != "->") {
std::vector<const Variable*> vars = getVariables(tok);
Token* ftok = tok->astParent()->tokAt(2);
if (Token::simpleMatch(tok->astParent(), ". reset (")) {
if (Token::simpleMatch(ftok, "( )")) {
ValueFlow::Value v(0);
v.setKnown();
valueFlowForwardAssign(ftok, tok, vars, {std::move(v)}, false, tokenlist, errorLogger, settings);
} else {
tok->removeValues(std::mem_fn(&ValueFlow::Value::isIntValue));
Token* inTok = ftok->astOperand2();
if (!inTok)
continue;
const std::list<ValueFlow::Value>& values = inTok->values();
valueFlowForwardAssign(inTok, tok, vars, values, false, tokenlist, errorLogger, settings);
}
} else if (Token::simpleMatch(tok->astParent(), ". release ( )")) {
const Token* parent = ftok->astParent();
bool hasParentReset = false;
while (parent) {
if (Token::Match(parent->tokAt(-2), ". release|reset (") &&
parent->tokAt(-2)->astOperand1()->exprId() == tok->exprId()) {
hasParentReset = true;
break;
}
parent = parent->astParent();
}
if (hasParentReset)
continue;
ValueFlow::Value v(0);
v.setKnown();
valueFlowForwardAssign(ftok, tok, vars, {std::move(v)}, false, tokenlist, errorLogger, settings);
} else if (Token::simpleMatch(tok->astParent(), ". get ( )")) {
ValueFlow::Value v = makeSymbolic(tok);
setTokenValue(tok->astParent()->tokAt(2), std::move(v), settings);
}
} else if (Token::Match(tok->previous(), "%name%|> (|{") && astIsSmartPointer(tok) &&
astIsSmartPointer(tok->astOperand1())) {
std::vector<const Token*> args = getArguments(tok);
if (args.empty())
continue;
for (const ValueFlow::Value& v : args.front()->values())
setTokenValue(tok, v, settings);
}
}
}
static Library::Container::Yield findIteratorYield(Token* tok, const Token** ftok, const Settings *settings)
{
auto yield = astContainerYield(tok, ftok);
if (*ftok)
return yield;
if (!tok->astParent())
return yield;
//begin/end free functions
return astFunctionYield(tok->astParent()->previous(), settings, ftok);
}
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;
Token* ftok = nullptr;
const Library::Container::Yield yield = findIteratorYield(tok, const_cast<const Token**>(&ftok), settings);
if (ftok) {
ValueFlow::Value v(0);
v.setKnown();
if (yield == Library::Container::Yield::START_ITERATOR) {
v.valueType = ValueFlow::Value::ValueType::ITERATOR_START;
setTokenValue(ftok->next(), std::move(v), settings);
} else if (yield == Library::Container::Yield::END_ITERATOR) {
v.valueType = ValueFlow::Value::ValueType::ITERATOR_END;
setTokenValue(ftok->next(), std::move(v), settings);
}
}
}
}
static std::list<ValueFlow::Value> getIteratorValues(std::list<ValueFlow::Value> values, const ValueFlow::Value::ValueKind* kind = nullptr)
{
values.remove_if([&](const ValueFlow::Value& v) {
if (kind && v.valueKind != *kind)
return true;
return !v.isIteratorValue();
});
return values;
}
struct IteratorConditionHandler : SimpleConditionHandler {
std::vector<Condition> parse(const Token* tok, const Settings* /*settings*/) const override {
Condition cond;
if (Token::Match(tok, "==|!=")) {
if (!tok->astOperand1() || !tok->astOperand2())
return {};
constexpr 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(), &kind);
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 {std::move(cond)};
}
};
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.condition)
return true;
if (v.bound != ValueFlow::Value::Bound::Point)
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, std::move(v), settings);
}
}
}
static std::vector<ValueFlow::Value> getContainerValues(const Token* tok)
{
std::vector<ValueFlow::Value> values;
if (tok) {
std::copy_if(tok->values().cbegin(),
tok->values().cend(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isContainerSizeValue));
}
return values;
}
static ValueFlow::Value makeContainerSizeValue(std::size_t s, bool known = true)
{
ValueFlow::Value value(s);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
if (known)
value.setKnown();
return value;
}
static std::vector<ValueFlow::Value> makeContainerSizeValue(const Token* tok, bool known = true)
{
if (tok->hasKnownIntValue())
return {makeContainerSizeValue(tok->values().front().intvalue, known)};
return {};
}
static std::vector<ValueFlow::Value> getContainerSizeFromConstructorArgs(const std::vector<const Token*>& args,
const Library::Container* container,
bool known)
{
if (astIsIntegral(args[0], false)) { // { count, i } or { count }
if (args.size() == 1 || (args.size() > 1 && !astIsIntegral(args[1], false)))
return {makeContainerSizeValue(args[0], known)};
} else if (astIsContainer(args[0]) && args.size() == 1) { // copy constructor
return getContainerValues(args[0]);
} else if (isIteratorPair(args)) {
std::vector<ValueFlow::Value> result = getContainerValues(args[0]);
if (!result.empty())
return result;
// (ptr, ptr + size)
if (astIsPointer(args[0]) && args[0]->exprId() != 0) {
// (ptr, ptr) is empty
// TODO: Use lifetime values to check if it points to the same address
if (args[0]->exprId() == args[1]->exprId())
return {makeContainerSizeValue(std::size_t{0}, known)};
// TODO: Insert iterator positions for pointers
if (Token::simpleMatch(args[1], "+")) {
nonneg int const eid = args[0]->exprId();
const Token* vartok = args[1]->astOperand1();
const Token* sizetok = args[1]->astOperand2();
if (sizetok->exprId() == eid)
std::swap(vartok, sizetok);
if (vartok->exprId() == eid && sizetok->hasKnownIntValue())
return {makeContainerSizeValue(sizetok, known)};
}
}
} else if (container->stdStringLike) {
if (astIsPointer(args[0])) {
// TODO: Try to read size of string literal { "abc" }
if (args.size() == 2 && astIsIntegral(args[1], false)) // { char*, count }
return {makeContainerSizeValue(args[1], known)};
} else if (astIsContainer(args[0])) {
if (args.size() == 1) // copy constructor { str }
return getContainerValues(args[0]);
if (args.size() == 3) // { str, pos, count }
return {makeContainerSizeValue(args[2], known)};
// TODO: { str, pos }, { ..., alloc }
}
}
return {};
}
static bool valueFlowIsSameContainerType(const ValueType& contType, const Token* tok, const Settings* settings)
{
if (!tok || !tok->valueType() || !tok->valueType()->containerTypeToken)
return true;
const ValueType tokType = ValueType::parseDecl(tok->valueType()->containerTypeToken, *settings);
return contType.isTypeEqual(&tokType) || tokType.type == ValueType::Type::UNKNOWN_TYPE;
}
static std::vector<ValueFlow::Value> getInitListSize(const Token* tok,
const ValueType* valueType,
const Settings* settings,
bool known = true)
{
std::vector<const Token*> args = getArguments(tok);
if (args.empty())
return {makeContainerSizeValue(std::size_t{0}, known)};
bool initList = true;
// Try to disambiguate init list from constructor
if (args.size() < 4) {
initList = !isIteratorPair(args) && !(args.size() < 3 && astIsIntegral(args[0], false));
const Token* containerTypeToken = valueType->containerTypeToken;
if (valueType->container->stdStringLike) {
initList = astIsGenericChar(args[0]) && !astIsPointer(args[0]);
} else if (containerTypeToken && settings) {
ValueType vt = ValueType::parseDecl(containerTypeToken, *settings);
if (vt.pointer > 0 && astIsPointer(args[0]))
initList = true;
else if (vt.type == ValueType::ITERATOR && astIsIterator(args[0]))
initList = true;
else if (vt.isIntegral() && astIsIntegral(args[0], false))
initList = true;
else if (args.size() == 1 && valueFlowIsSameContainerType(vt, tok->astOperand2(), settings))
initList = false; // copy ctor
}
}
if (!initList)
return getContainerSizeFromConstructorArgs(args, valueType->container, known);
return {makeContainerSizeValue(args.size(), known)};
}
static std::vector<ValueFlow::Value> getContainerSizeFromConstructor(const Token* tok,
const ValueType* valueType,
const Settings* settings,
bool known = true)
{
std::vector<const Token*> args = getArguments(tok);
if (args.empty())
return {makeContainerSizeValue(std::size_t{0}, known)};
// Init list in constructor
if (args.size() == 1 && Token::simpleMatch(args[0], "{"))
return getInitListSize(args[0], valueType, settings, known);
return getContainerSizeFromConstructorArgs(args, valueType->container, known);
}
static void valueFlowContainerSetTokValue(TokenList& tokenlist, const Settings* settings, const Token* tok, Token* initList)
{
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = initList;
if (astIsContainerString(tok) && Token::simpleMatch(initList, "{") && Token::Match(initList->astOperand2(), "%str%")) {
value.tokvalue = initList->astOperand2();
}
value.setKnown();
Token* start = initList->link() ? initList->link() : initList->next();
if (tok->variable() && tok->variable()->isConst()) {
valueFlowForwardConst(start, tok->variable()->scope()->bodyEnd, tok->variable(), {value}, settings);
} else {
valueFlowForward(start, tok, value, tokenlist, settings);
}
}
static const Scope* getFunctionScope(const Scope* scope) {
while (scope && scope->type != Scope::ScopeType::eFunction)
scope = scope->nestedIn;
return scope;
}
static MathLib::bigint valueFlowGetStrLength(const Token* tok)
{
if (tok->tokType() == Token::eString)
return Token::getStrLength(tok);
if (astIsGenericChar(tok) || tok->tokType() == Token::eChar)
return 1;
if (const ValueFlow::Value* v = tok->getKnownValue(ValueFlow::Value::ValueType::CONTAINER_SIZE))
return v->intvalue;
if (const ValueFlow::Value* v = tok->getKnownValue(ValueFlow::Value::ValueType::TOK)) {
if (v->tokvalue != tok)
return valueFlowGetStrLength(v->tokvalue);
}
return 0;
}
static void valueFlowContainerSize(TokenList& tokenlist,
const SymbolDatabase& symboldatabase,
ErrorLogger* /*errorLogger*/,
const Settings* settings,
const std::set<const Scope*>& skippedFunctions)
{
// declaration
for (const Variable *var : symboldatabase.variableList()) {
if (!var)
continue;
if (!var->scope() || !var->scope()->bodyEnd || !var->scope()->bodyStart)
continue;
if (!var->valueType() || !var->valueType()->container)
continue;
if (!astIsContainer(var->nameToken()))
continue;
if (skippedFunctions.count(getFunctionScope(var->scope())))
continue;
bool known = true;
int size = 0;
const bool nonLocal = !var->isLocal() || var->isPointer() || var->isReference() || var->isStatic();
bool constSize = var->isConst() && !nonLocal;
bool staticSize = false;
if (var->valueType()->container->size_templateArgNo >= 0) {
staticSize = true;
constSize = true;
size = -1;
if (var->dimensions().size() == 1) {
const Dimension& dim = var->dimensions().front();
if (dim.known) {
size = dim.num;
} else if (dim.tok && dim.tok->hasKnownIntValue()) {
size = dim.tok->values().front().intvalue;
}
}
if (size < 0)
continue;
}
if (!staticSize && nonLocal)
continue;
Token* nameToken = const_cast<Token*>(var->nameToken());
if (nameToken->hasKnownValue(ValueFlow::Value::ValueType::CONTAINER_SIZE))
continue;
if (!staticSize) {
if (!Token::Match(nameToken, "%name% ;") &&
!(Token::Match(nameToken, "%name% {") && Token::simpleMatch(nameToken->next()->link(), "} ;")) &&
!Token::Match(nameToken, "%name% ("))
continue;
}
if (nameToken->astTop() && Token::Match(nameToken->astTop()->previous(), "for|while"))
known = !isVariableChanged(var, settings, true);
std::vector<ValueFlow::Value> values{ValueFlow::Value{size}};
values.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
if (known)
values.back().setKnown();
if (!staticSize) {
if (Token::simpleMatch(nameToken->next(), "{")) {
Token* initList = nameToken->next();
valueFlowContainerSetTokValue(tokenlist, settings, nameToken, initList);
values = getInitListSize(initList, var->valueType(), settings, known);
} else if (Token::simpleMatch(nameToken->next(), "(")) {
const Token* constructorArgs = nameToken->next();
values = getContainerSizeFromConstructor(constructorArgs, var->valueType(), settings, known);
}
}
if (constSize) {
valueFlowForwardConst(nameToken->next(), var->scope()->bodyEnd, var, values, settings);
continue;
}
for (const ValueFlow::Value& value : values) {
valueFlowForward(nameToken->next(), var->nameToken(), value, tokenlist, settings);
}
}
// after assignment
for (const Scope *functionScope : symboldatabase.functionScopes) {
for (Token* tok = const_cast<Token*>(functionScope->bodyStart); tok != functionScope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "%name%|;|{|} %var% = %str% ;")) {
Token* containerTok = tok->next();
if (containerTok->exprId() == 0)
continue;
if (containerTok->valueType() && containerTok->valueType()->container &&
containerTok->valueType()->container->stdStringLike) {
valueFlowContainerSetTokValue(tokenlist, settings, containerTok, containerTok->tokAt(2));
ValueFlow::Value value(Token::getStrLength(containerTok->tokAt(2)));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowForward(containerTok->next(), containerTok, value, tokenlist, settings);
}
} else if (Token::Match(tok->previous(), ">|return (|{") && astIsContainer(tok) && getLibraryContainer(tok)->size_templateArgNo < 0) {
std::vector<ValueFlow::Value> values;
if (Token::simpleMatch(tok, "{")) {
values = getInitListSize(tok, tok->valueType(), settings, true);
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = tok;
value.setKnown();
values.push_back(value);
} else if (Token::simpleMatch(tok, "(")) {
const Token* constructorArgs = tok;
values = getContainerSizeFromConstructor(constructorArgs, tok->valueType(), settings, true);
}
for (const ValueFlow::Value& value : values)
setTokenValue(tok, value, settings);
} else if (Token::Match(tok, "%name%|;|{|}|> %var% = {") && Token::simpleMatch(tok->linkAt(3), "} ;")) {
Token* containerTok = tok->next();
if (containerTok->exprId() == 0)
continue;
if (astIsContainer(containerTok) && containerTok->valueType()->container->size_templateArgNo < 0) {
std::vector<ValueFlow::Value> values =
getInitListSize(tok->tokAt(3), containerTok->valueType(), settings);
valueFlowContainerSetTokValue(tokenlist, settings, containerTok, tok->tokAt(3));
for (const ValueFlow::Value& value : values)
valueFlowForward(containerTok->next(), containerTok, value, tokenlist, settings);
}
} else if (Token::Match(tok, ". %name% (") && tok->astOperand1() && tok->astOperand1()->valueType() &&
tok->astOperand1()->valueType()->container) {
const Token* containerTok = tok->astOperand1();
if (containerTok->exprId() == 0)
continue;
const Library::Container::Action action = containerTok->valueType()->container->getAction(tok->strAt(1));
if (action == Library::Container::Action::CLEAR) {
ValueFlow::Value value(0);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowForward(tok->next(), containerTok, value, tokenlist, settings);
} else if (action == Library::Container::Action::RESIZE && tok->tokAt(2)->astOperand2() &&
tok->tokAt(2)->astOperand2()->hasKnownIntValue()) {
ValueFlow::Value value(tok->tokAt(2)->astOperand2()->values().front());
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowForward(tok->linkAt(2), containerTok, value, tokenlist, settings);
} else if (action == Library::Container::Action::PUSH && !isIteratorPair(getArguments(tok->tokAt(2)))) {
ValueFlow::Value value(0);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setImpossible();
valueFlowForward(tok->linkAt(2), containerTok, value, tokenlist, settings);
}
} else if (Token::simpleMatch(tok, "+=") && astIsContainer(tok->astOperand1())) {
const Token* containerTok = tok->astOperand1();
const Token* valueTok = tok->astOperand2();
MathLib::bigint size = valueFlowGetStrLength(valueTok);
if (size == 0)
continue;
ValueFlow::Value value(size - 1);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.bound = ValueFlow::Value::Bound::Upper;
value.setImpossible();
Token* next = nextAfterAstRightmostLeaf(tok);
if (!next)
next = tok->next();
valueFlowForward(next, containerTok, value, tokenlist, settings);
}
}
}
}
struct ContainerConditionHandler : ConditionHandler {
std::vector<Condition> parse(const Token* tok, const Settings* settings) const override
{
std::vector<Condition> conds;
parseCompareEachInt(tok, [&](const Token* vartok, ValueFlow::Value true_value, ValueFlow::Value false_value) {
vartok = settings->library.getContainerFromYield(vartok, Library::Container::Yield::SIZE);
if (!vartok)
return;
true_value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
false_value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
Condition cond;
cond.true_values.push_back(std::move(true_value));
cond.false_values.push_back(std::move(false_value));
cond.vartok = vartok;
conds.push_back(std::move(cond));
});
if (!conds.empty())
return conds;
const Token* vartok = nullptr;
// Empty check
if (tok->str() == "(") {
vartok = settings->library.getContainerFromYield(tok, Library::Container::Yield::EMPTY);
// TODO: Handle .size()
if (!vartok)
return {};
const Token *parent = tok->astParent();
while (parent) {
if (Token::Match(parent, "%comp%"))
return {};
parent = parent->astParent();
}
ValueFlow::Value value(tok, 0LL);
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
Condition cond;
cond.true_values.emplace_back(value);
cond.false_values.emplace_back(std::move(value));
cond.vartok = vartok;
cond.inverted = true;
return {std::move(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 {};
if (!astIsContainer(vartok))
return {};
ValueFlow::Value value(tok, Token::getStrLength(strtok));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
Condition cond;
cond.false_values.emplace_back(value);
cond.true_values.emplace_back(std::move(value));
cond.vartok = vartok;
cond.impossible = false;
return {std::move(cond)};
}
return {};
}
};
static void valueFlowDynamicBufferSize(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, const Settings* settings)
{
auto getBufferSizeFromAllocFunc = [&](const Token* funcTok) -> MathLib::bigint {
MathLib::bigint sizeValue = -1;
const Library::AllocFunc* allocFunc = settings->library.getAllocFuncInfo(funcTok);
if (!allocFunc)
allocFunc = settings->library.getReallocFuncInfo(funcTok);
if (!allocFunc || allocFunc->bufferSize == Library::AllocFunc::BufferSize::none)
return sizeValue;
const std::vector<const Token*> args = getArguments(funcTok);
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;
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;
}
return sizeValue;
};
auto getBufferSizeFromNew = [&](const Token* newTok) -> MathLib::bigint {
MathLib::bigint sizeValue = -1, numElem = -1;
if (newTok && newTok->astOperand1()) { // number of elements
const Token* bracTok = nullptr, *typeTok = nullptr;
if (newTok->astOperand1()->str() == "[")
bracTok = newTok->astOperand1();
else if (Token::Match(newTok->astOperand1(), "(|{")) {
if (newTok->astOperand1()->astOperand1() && newTok->astOperand1()->astOperand1()->str() == "[")
bracTok = newTok->astOperand1()->astOperand1();
else
typeTok = newTok->astOperand1()->astOperand1();
}
else
typeTok = newTok->astOperand1();
if (bracTok && bracTok->astOperand2() && bracTok->astOperand2()->hasKnownIntValue())
numElem = bracTok->astOperand2()->getKnownIntValue();
else if (Token::Match(typeTok, "%type%"))
numElem = 1;
}
if (numElem >= 0 && newTok->astParent() && newTok->astParent()->isAssignmentOp()) { // size of the allocated type
const Token* typeTok = newTok->astParent()->astOperand1(); // TODO: implement fallback for e.g. "auto p = new Type;"
if (!typeTok || !typeTok->varId())
typeTok = newTok->astParent()->previous(); // hack for "int** z = ..."
if (typeTok && typeTok->valueType()) {
const MathLib::bigint typeSize = typeTok->valueType()->typeSize(settings->platform, typeTok->valueType()->pointer > 1);
if (typeSize >= 0)
sizeValue = numElem * typeSize;
}
}
return sizeValue;
};
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;
const bool isNew = symboldatabase.isCPP() && rhs->str() == "new";
if (!isNew && !Token::Match(rhs->previous(), "%name% ("))
continue;
const MathLib::bigint sizeValue = isNew ? getBufferSizeFromNew(rhs) : getBufferSizeFromAllocFunc(rhs->previous());
if (sizeValue < 0)
continue;
ValueFlow::Value value(sizeValue);
value.errorPath.emplace_back(tok->tokAt(2), "Assign " + tok->strAt(1) + ", buffer with size " + std::to_string(sizeValue));
value.valueType = ValueFlow::Value::ValueType::BUFFER_SIZE;
value.setKnown();
valueFlowForward(const_cast<Token*>(rhs), functionScope->bodyEnd, tok->next(), std::move(value), tokenlist, settings);
}
}
}
static bool getMinMaxValues(const ValueType *vt, const 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->platform, minvalue, maxvalue);
}
static void valueFlowSafeFunctions(TokenList& tokenlist, const SymbolDatabase& symboldatabase, 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->platform.type != Platform::Type::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)
valueFlowForward(const_cast<Token*>(functionScope->bodyStart), arg.nameToken(), value, tokenlist, settings);
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->platform, 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 : -1E25;
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 : 1E25;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue));
argValues.back().safe = true;
valueFlowForward(const_cast<Token*>(functionScope->bodyStart->next()),
functionScope->bodyEnd,
arg.nameToken(),
argValues,
tokenlist,
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 " + std::to_string(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 " + std::to_string(high));
argValues.back().safe = safeHigh;
}
if (!argValues.empty())
valueFlowForward(const_cast<Token*>(functionScope->bodyStart->next()),
functionScope->bodyEnd,
arg.nameToken(),
argValues,
tokenlist,
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(tok, ValueFlow::Value(value), settings);
}
}
}
static void valueFlowDebug(TokenList& tokenlist, ErrorLogger* errorLogger, const Settings* settings)
{
if (!settings->debugnormal && !settings->debugwarnings)
return;
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->getTokenDebug() != TokenDebug::ValueFlow)
continue;
if (tok->astParent() && tok->astParent()->getTokenDebug() == TokenDebug::ValueFlow)
continue;
for (const ValueFlow::Value& v : tok->values()) {
std::string msg = "The value is " + debugString(v);
ErrorPath errorPath = v.errorPath;
errorPath.insert(errorPath.end(), v.debugPath.cbegin(), v.debugPath.cend());
errorPath.emplace_back(tok, "");
errorLogger->reportErr({errorPath, &tokenlist, Severity::debug, "valueFlow", msg, CWE{0}, Certainty::normal});
}
}
}
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;
}
struct ValueFlowState {
explicit ValueFlowState(TokenList& tokenlist,
SymbolDatabase& symboldatabase,
ErrorLogger* errorLogger = nullptr,
const Settings* settings = nullptr)
: tokenlist(tokenlist), symboldatabase(symboldatabase), errorLogger(errorLogger), settings(settings)
{}
TokenList& tokenlist;
SymbolDatabase& symboldatabase;
ErrorLogger* errorLogger = nullptr;
const Settings* settings = nullptr;
std::set<const Scope*> skippedFunctions;
};
struct ValueFlowPass {
ValueFlowPass() = default;
ValueFlowPass(const ValueFlowPass&) = default;
// Name of pass
virtual const char* name() const = 0;
// Run the pass
virtual void run(const ValueFlowState& state) const = 0;
// Returns true if pass needs C++
virtual bool cpp() const = 0;
virtual ~ValueFlowPass() noexcept = default;
};
struct ValueFlowPassRunner {
using Clock = std::chrono::steady_clock;
using TimePoint = std::chrono::time_point<Clock>;
explicit ValueFlowPassRunner(ValueFlowState state, TimerResultsIntf* timerResults = nullptr)
: state(std::move(state)), stop(TimePoint::max()), timerResults(timerResults)
{
setSkippedFunctions();
setStopTime();
}
bool run_once(std::initializer_list<ValuePtr<ValueFlowPass>> passes) const
{
return std::any_of(passes.begin(), passes.end(), [&](const ValuePtr<ValueFlowPass>& pass) {
return run(pass);
});
}
bool run(std::initializer_list<ValuePtr<ValueFlowPass>> passes) const
{
std::size_t values = 0;
std::size_t n = state.settings->valueFlowMaxIterations;
while (n > 0 && values != getTotalValues()) {
values = getTotalValues();
if (std::any_of(passes.begin(), passes.end(), [&](const ValuePtr<ValueFlowPass>& pass) {
return run(pass);
}))
return true;
--n;
}
if (state.settings->debugwarnings) {
if (n == 0 && values != getTotalValues()) {
ErrorMessage::FileLocation loc;
loc.setfile(state.tokenlist.getFiles()[0]);
ErrorMessage errmsg({std::move(loc)},
emptyString,
Severity::debug,
"ValueFlow maximum iterations exceeded",
"valueFlowMaxIterations",
Certainty::normal);
state.errorLogger->reportErr(errmsg);
}
}
return false;
}
bool run(const ValuePtr<ValueFlowPass>& pass) const
{
auto start = Clock::now();
if (start > stop)
return true;
if (!state.tokenlist.isCPP() && pass->cpp())
return false;
if (timerResults) {
Timer t(pass->name(), state.settings->showtime, timerResults);
pass->run(state);
} else {
pass->run(state);
}
return false;
}
std::size_t getTotalValues() const
{
std::size_t n = 1;
for (Token* tok = state.tokenlist.front(); tok; tok = tok->next())
n += tok->values().size();
return n;
}
void setSkippedFunctions()
{
if (state.settings->performanceValueFlowMaxIfCount > 0) {
for (const Scope* functionScope : state.symboldatabase.functionScopes) {
int countIfScopes = 0;
std::vector<const Scope*> scopes{functionScope};
while (!scopes.empty()) {
const Scope* s = scopes.back();
scopes.pop_back();
for (const Scope* s2 : s->nestedList) {
scopes.emplace_back(s2);
if (s2->type == Scope::ScopeType::eIf)
++countIfScopes;
}
}
if (countIfScopes > state.settings->performanceValueFlowMaxIfCount) {
state.skippedFunctions.emplace(functionScope);
if (state.settings->severity.isEnabled(Severity::information)) {
const std::string& functionName = functionScope->className;
const std::list<ErrorMessage::FileLocation> callstack(
1,
ErrorMessage::FileLocation(functionScope->bodyStart, &state.tokenlist));
const ErrorMessage errmsg(callstack,
state.tokenlist.getSourceFilePath(),
Severity::information,
"Limiting ValueFlow analysis in function '" + functionName + "' since it is too complex. "
"Please specify --check-level=exhaustive to perform full analysis.",
"checkLevelNormal",
Certainty::normal);
state.errorLogger->reportErr(errmsg);
}
}
}
}
}
void setStopTime()
{
if (state.settings->performanceValueFlowMaxTime >= 0)
stop = Clock::now() + std::chrono::seconds{state.settings->performanceValueFlowMaxTime};
}
ValueFlowState state;
TimePoint stop;
TimerResultsIntf* timerResults;
};
template<class F>
struct ValueFlowPassAdaptor : ValueFlowPass {
const char* mName = nullptr;
bool mCPP = false;
F mRun;
ValueFlowPassAdaptor(const char* pname, bool pcpp, F prun) : ValueFlowPass(), mName(pname), mCPP(pcpp), mRun(prun) {}
const char* name() const override {
return mName;
}
void run(const ValueFlowState& state) const override
{
mRun(state.tokenlist, state.symboldatabase, state.errorLogger, state.settings, state.skippedFunctions);
}
bool cpp() const override {
return mCPP;
}
};
template<class F>
static ValueFlowPassAdaptor<F> makeValueFlowPassAdaptor(const char* name, bool cpp, F run)
{
return {name, cpp, run};
}
#define VALUEFLOW_ADAPTOR(cpp, ...) \
makeValueFlowPassAdaptor(#__VA_ARGS__, \
cpp, \
[](TokenList& tokenlist, \
SymbolDatabase& symboldatabase, \
ErrorLogger* errorLogger, \
const Settings* settings, \
const std::set<const Scope*>& skippedFunctions) { \
(void)tokenlist; \
(void)symboldatabase; \
(void)errorLogger; \
(void)settings; \
(void)skippedFunctions; \
__VA_ARGS__; \
})
#define VFA(...) VALUEFLOW_ADAPTOR(false, __VA_ARGS__)
#define VFA_CPP(...) VALUEFLOW_ADAPTOR(true, __VA_ARGS__)
void ValueFlow::setValues(TokenList& tokenlist,
SymbolDatabase& symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings,
TimerResultsIntf* timerResults)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next())
tok->clearValueFlow();
// commas in init..
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->str() != "{" || !tok->astOperand1())
continue;
for (Token* tok2 = tok->next(); tok2 != tok->link(); tok2 = tok2->next()) {
if (tok2->link() && Token::Match(tok2, "[{[(<]"))
tok2 = tok2->link();
else if (tok2->str() == ",")
tok2->isInitComma(true);
}
}
ValueFlowPassRunner runner{ValueFlowState{tokenlist, symboldatabase, errorLogger, settings}, timerResults};
runner.run_once({
VFA(valueFlowEnumValue(symboldatabase, settings)),
VFA(valueFlowNumber(tokenlist, settings)),
VFA(valueFlowString(tokenlist, settings)),
VFA(valueFlowArray(tokenlist, settings)),
VFA(valueFlowUnknownFunctionReturn(tokenlist, settings)),
VFA(valueFlowGlobalConstVar(tokenlist, settings)),
VFA(valueFlowEnumValue(symboldatabase, settings)),
VFA(valueFlowGlobalStaticVar(tokenlist, settings)),
VFA(valueFlowPointerAlias(tokenlist, settings)),
VFA(valueFlowLifetime(tokenlist, errorLogger, settings)),
VFA(valueFlowSymbolic(tokenlist, symboldatabase, settings)),
VFA(valueFlowBitAnd(tokenlist, settings)),
VFA(valueFlowSameExpressions(tokenlist, settings)),
VFA(valueFlowConditionExpressions(tokenlist, symboldatabase, errorLogger, *settings)),
});
runner.run({
VFA(valueFlowImpossibleValues(tokenlist, settings)),
VFA(valueFlowSymbolicOperators(symboldatabase, settings)),
VFA(valueFlowCondition(SymbolicConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)),
VFA(valueFlowSymbolicInfer(symboldatabase, settings)),
VFA(valueFlowArrayBool(tokenlist, settings)),
VFA(valueFlowArrayElement(tokenlist, settings)),
VFA(valueFlowRightShift(tokenlist, settings)),
VFA(valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)),
VFA_CPP(valueFlowAfterSwap(tokenlist, symboldatabase, errorLogger, settings)),
VFA(valueFlowCondition(SimpleConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)),
VFA(valueFlowInferCondition(tokenlist, settings)),
VFA(valueFlowSwitchVariable(tokenlist, symboldatabase, errorLogger, settings)),
VFA(valueFlowForLoop(tokenlist, symboldatabase, errorLogger, settings)),
VFA(valueFlowSubFunction(tokenlist, symboldatabase, errorLogger, *settings)),
VFA(valueFlowFunctionReturn(tokenlist, errorLogger, settings)),
VFA(valueFlowLifetime(tokenlist, errorLogger, settings)),
VFA(valueFlowFunctionDefaultParameter(tokenlist, symboldatabase, settings)),
VFA(valueFlowUninit(tokenlist, settings)),
VFA_CPP(valueFlowAfterMove(tokenlist, symboldatabase, settings)),
VFA_CPP(valueFlowSmartPointer(tokenlist, errorLogger, settings)),
VFA_CPP(valueFlowIterators(tokenlist, settings)),
VFA_CPP(
valueFlowCondition(IteratorConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)),
VFA_CPP(valueFlowIteratorInfer(tokenlist, settings)),
VFA_CPP(valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)),
VFA_CPP(
valueFlowCondition(ContainerConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings, skippedFunctions)),
VFA(valueFlowSafeFunctions(tokenlist, symboldatabase, settings)),
});
runner.run_once({
VFA(valueFlowDynamicBufferSize(tokenlist, symboldatabase, settings)),
VFA(valueFlowDebug(tokenlist, 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";
}
const ValueFlow::Value* ValueFlow::findValue(const std::list<ValueFlow::Value>& values,
const Settings* settings,
const std::function<bool(const ValueFlow::Value&)> &pred)
{
const ValueFlow::Value* ret = nullptr;
for (const ValueFlow::Value& v : values) {
if (pred(v)) {
if (!ret || ret->isInconclusive() || (ret->condition && !v.isInconclusive()))
ret = &v;
if (!ret->isInconclusive() && !ret->condition)
break;
}
}
if (settings && ret) {
if (ret->isInconclusive() && !settings->certainty.isEnabled(Certainty::inconclusive))
return nullptr;
if (ret->condition && !settings->severity.isEnabled(Severity::warning))
return nullptr;
}
return ret;
}
// TODO: returns a single value at most - no need for std::vector
static std::vector<ValueFlow::Value> isOutOfBoundsImpl(const ValueFlow::Value& size,
const Token* indexTok,
bool condition)
{
if (!indexTok)
return {};
const ValueFlow::Value* indexValue = indexTok->getMaxValue(condition, size.path);
if (!indexValue)
return {};
if (indexValue->intvalue >= size.intvalue)
return {*indexValue};
if (!condition)
return {};
// TODO: Use a better way to decide if the variable in unconstrained
if (!indexTok->variable() || !indexTok->variable()->isArgument())
return {};
if (std::any_of(indexTok->values().cbegin(), indexTok->values().cend(), [&](const ValueFlow::Value& v) {
return v.isSymbolicValue() && v.isPossible() && v.bound == ValueFlow::Value::Bound::Upper;
}))
return {};
if (indexValue->bound != ValueFlow::Value::Bound::Lower)
return {};
if (size.bound == ValueFlow::Value::Bound::Lower)
return {};
// Checking for underflow doesn't mean it could be out of bounds
if (indexValue->intvalue == 0)
return {};
ValueFlow::Value value = inferCondition(">=", indexTok, indexValue->intvalue);
if (!value.isKnown())
return {};
if (value.intvalue == 0)
return {};
value.intvalue = size.intvalue;
value.bound = ValueFlow::Value::Bound::Lower;
return {std::move(value)};
}
// TODO: return single value at most - no need for std::vector
std::vector<ValueFlow::Value> ValueFlow::isOutOfBounds(const Value& size, const Token* indexTok, bool possible)
{
ValueFlow::Value inBoundsValue = inferCondition("<", indexTok, size.intvalue);
if (inBoundsValue.isKnown() && inBoundsValue.intvalue != 0)
return {};
std::vector<ValueFlow::Value> result = isOutOfBoundsImpl(size, indexTok, false);
if (!result.empty())
return result;
if (!possible)
return result;
return isOutOfBoundsImpl(size, indexTok, true);
}
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