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cppcheck/lib/valueflow.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2022 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 "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 "standards.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenlist.h"
#include "utils.h"
#include "valueptr.h"
#include <algorithm>
#include <array>
#include <cassert>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <exception>
#include <functional>
#include <initializer_list>
#include <iosfwd>
#include <iterator>
#include <limits>
#include <map>
#include <memory>
#include <set>
#include <stack>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <vector>
static void bailoutInternal(const std::string& type, 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));
ErrorMessage errmsg(callstack, tokenlist->getSourceFilePath(), Severity::debug,
Path::stripDirectoryPart(file) + ":" + MathLib::toString(line) + ":" + function + " bailout: " + what, type, Certainty::normal);
errorLogger->reportErr(errmsg);
}
#if (defined __cplusplus) && __cplusplus >= 201103L
#define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __func__)
#elif (defined __GNUC__) || (defined __clang__) || (defined _MSC_VER)
#define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, __FUNCTION__)
#else
#define bailout2(type, tokenlist, errorLogger, tok, what) bailoutInternal(type, tokenlist, errorLogger, tok, what, __FILE__, __LINE__, "(valueFlow)")
#endif
#define bailout(tokenlist, errorLogger, tok, what) bailout2("valueFlowBailout", tokenlist, errorLogger, tok, what)
#define bailoutIncompleteVar(tokenlist, errorLogger, tok, what) bailout2("valueFlowBailoutIncompleteVar", tokenlist, errorLogger, tok, what)
static void changeKnownToPossible(std::list<ValueFlow::Value> &values, int indirect=-1)
{
for (ValueFlow::Value& v: values) {
if (indirect >= 0 && v.indirect != indirect)
continue;
v.changeKnownToPossible();
}
}
static void removeImpossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
values.remove_if([&](const ValueFlow::Value& v) {
if (indirect >= 0 && v.indirect != indirect)
return false;
return v.isImpossible();
});
}
static void lowerToPossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
changeKnownToPossible(values, indirect);
removeImpossible(values, indirect);
}
static void changePossibleToKnown(std::list<ValueFlow::Value>& values, int indirect = -1)
{
for (ValueFlow::Value& v : values) {
if (indirect >= 0 && v.indirect != indirect)
continue;
if (!v.isPossible())
continue;
if (v.bound != ValueFlow::Value::Bound::Point)
continue;
v.setKnown();
}
}
static void setValueUpperBound(ValueFlow::Value& value, bool upper)
{
if (upper)
value.bound = ValueFlow::Value::Bound::Upper;
else
value.bound = ValueFlow::Value::Bound::Lower;
}
static void setValueBound(ValueFlow::Value& value, const Token* tok, bool invert)
{
if (Token::Match(tok, "<|<=")) {
setValueUpperBound(value, !invert);
} else if (Token::Match(tok, ">|>=")) {
setValueUpperBound(value, invert);
}
}
static void setConditionalValues(const Token* tok,
bool lhs,
MathLib::bigint value,
ValueFlow::Value& true_value,
ValueFlow::Value& false_value)
{
if (Token::Match(tok, "==|!=|>=|<=")) {
true_value = ValueFlow::Value{tok, value};
const char* greaterThan = ">=";
const char* lessThan = "<=";
if (lhs)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
false_value = ValueFlow::Value{tok, value - 1};
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
false_value = ValueFlow::Value{tok, value + 1};
} else {
false_value = ValueFlow::Value{tok, value};
}
} else {
const char* greaterThan = ">";
const char* lessThan = "<";
if (lhs)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
true_value = ValueFlow::Value{tok, value + 1};
false_value = ValueFlow::Value{tok, value};
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
true_value = ValueFlow::Value{tok, value - 1};
false_value = ValueFlow::Value{tok, value};
}
}
setValueBound(true_value, tok, 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();
}
const Token *parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value, const std::function<std::vector<MathLib::bigint>(const Token*)>& evaluate)
{
if (!tok->astOperand1() || !tok->astOperand2())
return nullptr;
if (tok->isComparisonOp()) {
std::vector<MathLib::bigint> value1 = evaluate(tok->astOperand1());
std::vector<MathLib::bigint> value2 = evaluate(tok->astOperand2());
if (!value1.empty() && !value2.empty()) {
if (tok->astOperand1()->hasKnownIntValue())
value2.clear();
if (tok->astOperand2()->hasKnownIntValue())
value1.clear();
}
if (!value1.empty()) {
if (isSaturated(value1.front()))
return nullptr;
setConditionalValues(tok, true, value1.front(), true_value, false_value);
return tok->astOperand2();
} else if (!value2.empty()) {
if (isSaturated(value2.front()))
return nullptr;
setConditionalValues(tok, false, value2.front(), true_value, false_value);
return tok->astOperand1();
}
}
return nullptr;
}
const Token *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, TokenList * tokenlist, bool unknown = false)
{
if (!Token::simpleMatch(tok, "{"))
return false;
// TODO this search for termTok in all subscopes. It should check the end of the scope.
const Token * termTok = Token::findmatch(tok, "return|continue|break|throw|goto", tok->link());
if (termTok && termTok->scope() == tok->scope())
return true;
std::string unknownFunction;
if (tokenlist && tokenlist->getSettings()->library.isScopeNoReturn(tok->link(), &unknownFunction))
return unknownFunction.empty() || unknown;
return false;
}
static 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) {
const MathLib::biguint one = 1;
value.intvalue &= (one << bit) - 1;
if (sign == ValueType::Sign::SIGNED && value.intvalue & (one << (bit - 1))) {
value.intvalue |= ~((one << bit) - 1ULL);
}
}
return value;
}
static bool isNumeric(const ValueFlow::Value& value) {
return value.isIntValue() || value.isFloatValue();
}
static void combineValueProperties(const ValueFlow::Value &value1, const ValueFlow::Value &value2, ValueFlow::Value *result)
{
if (value1.isKnown() && value2.isKnown())
result->setKnown();
else if (value1.isImpossible() || value2.isImpossible())
result->setImpossible();
else if (value1.isInconclusive() || value2.isInconclusive())
result->setInconclusive();
else
result->setPossible();
if (value1.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)
{
// 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%"))
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 tok->isComparisonOp() || Token::Match(tok, "%|/|&|%or%|<<|>>");
}
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() || value.tokvalue->tokType() != Token::eString))
return false;
return true;
}
/** Set token value for cast */
static void setTokenValueCast(Token *parent, const ValueType &valueType, const ValueFlow::Value &value, const Settings *settings);
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;
size_t n1 = ValueFlow::getSizeOf(*vt1, settings);
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)
{
// 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 (!tok->addValue(value))
return;
if (value.path < 0)
return;
Token *parent = tok->astParent();
if (!parent)
return;
if (Token::simpleMatch(parent, "=") && astIsRHS(tok) && !value.isLifetimeValue()) {
setTokenValue(parent, value, settings);
return;
}
if (value.isContainerSizeValue()) {
// .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, result, settings);
}
}
}
else if (Token::Match(parent, ". %name% (") && parent->astParent() == parent->tokAt(2) &&
parent->astOperand1() && parent->astOperand1()->valueType()) {
const Library::Container* c = getLibraryContainer(parent->astOperand1());
const Library::Container::Yield yields = c ? c->getYield(parent->strAt(1)) : Library::Container::Yield::NO_YIELD;
if (yields == Library::Container::Yield::SIZE) {
ValueFlow::Value v(value);
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(parent->astParent(), v, settings);
} else if (yields == Library::Container::Yield::EMPTY) {
ValueFlow::Value v(value);
v.intvalue = !v.intvalue;
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(parent->astParent(), v, settings);
}
} else if (Token::Match(parent->previous(), "%name% (")) {
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;
setTokenValue(parent, v, settings);
} else if (f->containerYield == Library::Container::Yield::EMPTY) {
ValueFlow::Value v(value);
v.intvalue = !v.intvalue;
v.valueType = ValueFlow::Value::ValueType::INT;
setTokenValue(parent, v, settings);
}
}
}
return;
}
if (value.isLifetimeValue()) {
if (!isLifetimeBorrowed(parent, settings))
return;
if (value.lifetimeKind == ValueFlow::Value::LifetimeKind::Iterator && astIsIterator(parent)) {
setTokenValue(parent,value,settings);
} else if (astIsPointer(tok) && astIsPointer(parent) && !parent->isUnaryOp("*") &&
(parent->isArithmeticalOp() || parent->isCast())) {
setTokenValue(parent,value,settings);
}
return;
}
if (value.isUninitValue()) {
if (Token::Match(tok, ". %var%"))
setTokenValue(tok->next(), value, settings);
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, pvalue, settings);
} else if (Token::Match(parent, ". %var%") && parent->astOperand1() == tok) {
if (parent->originalName() == "->" && pvalue.indirect > 0)
pvalue.indirect--;
setTokenValue(parent->astOperand2(), pvalue, settings);
} else if (Token::Match(parent->astParent(), ". %var%") && parent->astParent()->astOperand1() == parent) {
if (parent->astParent()->originalName() == "->" && pvalue.indirect > 0)
pvalue.indirect--;
setTokenValue(parent->astParent()->astOperand2(), pvalue, settings);
} else if (parent->isUnaryOp("*") && pvalue.indirect > 0) {
pvalue.indirect--;
setTokenValue(parent, pvalue, settings);
}
return;
}
// cast..
if (const Token *castType = getCastTypeStartToken(parent)) {
if (((tok->valueType() == nullptr && value.isImpossible()) || astIsPointer(tok)) &&
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.begin(), values.end(), value) != values.end())
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, "[&*]") && value.isKnown() && value.isIntValue() && value.intvalue==0) {
setTokenValue(parent, value, settings);
return;
}
// known result when a operand is true.
if (Token::simpleMatch(parent, "&&") && value.isKnown() && value.isIntValue() && value.intvalue==0) {
setTokenValue(parent, value, settings);
return;
}
// known result when a operand is false.
if (Token::simpleMatch(parent, "||") && value.isKnown() && value.isIntValue() && value.intvalue!=0) {
setTokenValue(parent, value, settings);
return;
}
for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) {
if (!isComputableValue(parent, value1))
continue;
for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) {
if (value1.path != value2.path)
continue;
if (!isComputableValue(parent, value2))
continue;
if (value1.isIteratorValue() && value2.isIteratorValue())
continue;
if (!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 MathLib::bigint intValue1 =
value1.isFloatValue() ? static_cast<MathLib::bigint>(value1.floatValue) : value1.intvalue;
const MathLib::bigint intValue2 =
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 {
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);
v.intvalue = !v.intvalue;
setTokenValue(parent, v, settings);
}
}
// ~
else if (parent->str() == "~") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue())
continue;
ValueFlow::Value v(val);
v.intvalue = ~v.intvalue;
int bits = 0;
if (settings &&
tok->valueType() &&
tok->valueType()->sign == ValueType::Sign::UNSIGNED &&
tok->valueType()->pointer == 0) {
if (tok->valueType()->type == ValueType::Type::INT)
bits = settings->int_bit;
else if (tok->valueType()->type == ValueType::Type::LONG)
bits = settings->long_bit;
}
if (bits > 0 && bits < MathLib::bigint_bits)
v.intvalue &= (((MathLib::biguint)1)<<bits) - 1;
setTokenValue(parent, v, settings);
}
}
// unary minus
else if (parent->isUnaryOp("-")) {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue())
continue;
ValueFlow::Value v(val);
if (v.isIntValue()) {
if (v.intvalue == LLONG_MIN)
// Value can't be inverted
continue;
v.intvalue = -v.intvalue;
} else
v.floatValue = -v.floatValue;
v.invertBound();
setTokenValue(parent, v, settings);
}
}
// increment
else if (parent->str() == "++") {
for (const ValueFlow::Value &val : tok->values()) {
if (!val.isIntValue() && !val.isFloatValue() && !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, 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, v, settings);
}
}
// Array element
else if (parent->str() == "[" && parent->isBinaryOp()) {
for (const ValueFlow::Value &value1 : parent->astOperand1()->values()) {
if (!value1.isTokValue())
continue;
for (const ValueFlow::Value &value2 : parent->astOperand2()->values()) {
if (!value2.isIntValue())
continue;
if (value1.varId == 0 || value2.varId == 0 ||
(value1.varId == value2.varId && value1.varvalue == value2.varvalue)) {
ValueFlow::Value result(0);
result.condition = value1.condition ? value1.condition : value2.condition;
result.setInconclusive(value1.isInconclusive() | value2.isInconclusive());
result.varId = (value1.varId != 0) ? value1.varId : value2.varId;
result.varvalue = (result.varId == value1.varId) ? value1.intvalue : value2.intvalue;
if (value1.valueKind == value2.valueKind)
result.valueKind = value1.valueKind;
if (value1.tokvalue->tokType() == Token::eString) {
const std::string s = value1.tokvalue->strValue();
const MathLib::bigint index = value2.intvalue;
if (index == s.size()) {
result.intvalue = 0;
setTokenValue(parent, result, settings);
} else if (index >= 0 && index < s.size()) {
result.intvalue = s[index];
setTokenValue(parent, result, settings);
}
} else if (value1.tokvalue->str() == "{") {
MathLib::bigint index = value2.intvalue;
const Token *element = value1.tokvalue->next();
while (index > 0 && element->str() != "}") {
if (element->str() == ",")
--index;
if (Token::Match(element, "[{}()[]]"))
break;
element = element->next();
}
if (Token::Match(element, "%num% [,}]")) {
result.intvalue = MathLib::toLongNumber(element->str());
setTokenValue(parent, result, settings);
}
}
}
}
}
}
else if (Token::Match(parent, ":: %name%") && parent->astOperand2() == tok) {
setTokenValue(parent, value, settings);
}
// 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, 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, 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->char_bit), settings);
else if (valueType.type == ValueType::Type::SHORT)
setTokenValue(parent, castValue(value, valueType.sign, settings->short_bit), settings);
else if (valueType.type == ValueType::Type::INT)
setTokenValue(parent, castValue(value, valueType.sign, settings->int_bit), settings);
else if (valueType.type == ValueType::Type::LONG)
setTokenValue(parent, castValue(value, valueType.sign, settings->long_bit), settings);
else if (valueType.type == ValueType::Type::LONGLONG)
setTokenValue(parent, castValue(value, valueType.sign, settings->long_long_bit), settings);
else if (valueType.isFloat() && isNumeric(value)) {
ValueFlow::Value floatValue = value;
floatValue.valueType = ValueFlow::Value::ValueType::FLOAT;
if (value.isIntValue())
floatValue.floatValue = value.intvalue;
setTokenValue(parent, floatValue, settings);
} else if (value.isIntValue()) {
const long long charMax = settings->signedCharMax();
const long long charMin = settings->signedCharMin();
if (charMin <= value.intvalue && value.intvalue <= charMax) {
// unknown type, but value is small so there should be no truncation etc
setTokenValue(parent,value,settings);
}
}
}
static nonneg int getSizeOfType(const Token *typeTok, const Settings *settings)
{
const ValueType &valueType = ValueType::parseDecl(typeTok, settings);
if (valueType.pointer > 0)
return settings->sizeof_pointer;
if (valueType.type == ValueType::Type::BOOL || valueType.type == ValueType::Type::CHAR)
return 1;
if (valueType.type == ValueType::Type::SHORT)
return settings->sizeof_short;
if (valueType.type == ValueType::Type::INT)
return settings->sizeof_int;
if (valueType.type == ValueType::Type::LONG)
return settings->sizeof_long;
if (valueType.type == ValueType::Type::LONGLONG)
return settings->sizeof_long_long;
if (valueType.type == ValueType::Type::WCHAR_T)
return settings->sizeof_wchar_t;
return 0;
}
size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings *settings)
{
if (vt.pointer)
return settings->sizeof_pointer;
if (vt.type == ValueType::Type::CHAR)
return 1;
if (vt.type == ValueType::Type::SHORT)
return settings->sizeof_short;
if (vt.type == ValueType::Type::WCHAR_T)
return settings->sizeof_wchar_t;
if (vt.type == ValueType::Type::INT)
return settings->sizeof_int;
if (vt.type == ValueType::Type::LONG)
return settings->sizeof_long;
if (vt.type == ValueType::Type::LONGLONG)
return settings->sizeof_long_long;
if (vt.type == ValueType::Type::FLOAT)
return settings->sizeof_float;
if (vt.type == ValueType::Type::DOUBLE)
return settings->sizeof_double;
if (vt.type == ValueType::Type::LONGDOUBLE)
return settings->sizeof_long_double;
return 0;
}
// Handle various constants..
static Token * valueFlowSetConstantValue(Token *tok, const Settings *settings, bool cpp)
{
if ((tok->isNumber() && MathLib::isInt(tok->str())) || (tok->tokType() == Token::eChar)) {
try {
ValueFlow::Value value(MathLib::toLongNumber(tok->str()));
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, 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, value, settings);
} else if (tok->enumerator() && tok->enumerator()->value_known) {
ValueFlow::Value value(tok->enumerator()->value);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, settings);
} else if (tok->str() == "NULL" || (cpp && tok->str() == "nullptr")) {
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, settings);
} else if (Token::simpleMatch(tok, "sizeof (")) {
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()->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(), value, settings);
return tok->linkAt(1);
}
}
const Token *tok2 = tok->tokAt(2);
// skip over tokens to find variable or type
while (Token::Match(tok2, "%name% ::|.|[")) {
if (tok2->next()->str() == "[")
tok2 = tok2->linkAt(1)->next();
else
tok2 = tok2->tokAt(2);
}
if (Token::simpleMatch(tok, "sizeof ( *")) {
const ValueType *vt = tok->tokAt(2)->valueType();
const size_t sz = vt ? ValueFlow::getSizeOf(*vt, settings) : 0;
if (sz > 0) {
ValueFlow::Value value(sz);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok->next(), value, settings);
}
} else if (tok2->enumerator() && tok2->enumerator()->scope) {
long long size = settings->sizeof_int;
const Token * type = tok2->enumerator()->scope->enumType;
if (type) {
size = getSizeOfType(type, settings);
if (size == 0)
tok->linkAt(1);
}
ValueFlow::Value value(size);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), value, settings);
} else if (tok2->type() && tok2->type()->isEnumType()) {
long long size = settings->sizeof_int;
if (tok2->type()->classScope) {
const Token * type = tok2->type()->classScope->enumType;
if (type) {
size = getSizeOfType(type, settings);
}
}
ValueFlow::Value value(size);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), value, settings);
} else if (Token::Match(tok, "sizeof ( %var% ) / sizeof (") && tok->next()->astParent() == tok->tokAt(4)) {
// Get number of elements in array
const Token *sz1 = tok->tokAt(2);
const Token *sz2 = tok->tokAt(7);
const nonneg int varid1 = sz1->varId();
if (varid1 &&
sz1->variable() &&
sz1->variable()->isArray() &&
!sz1->variable()->dimensions().empty() &&
sz1->variable()->dimensionKnown(0) &&
(Token::Match(sz2, "* %varid% )", varid1) || Token::Match(sz2, "%varid% [ 0 ] )", varid1))) {
ValueFlow::Value value(sz1->variable()->dimension(0));
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok->tokAt(4), value, settings);
}
} else if (Token::Match(tok2, "%var% )")) {
const Variable *var = tok2->variable();
// only look for single token types (no pointers or references yet)
if (var && var->typeStartToken() == var->typeEndToken()) {
// find the size of the type
size_t size = 0;
if (var->isEnumType()) {
size = settings->sizeof_int;
if (var->type()->classScope && var->type()->classScope->enumType)
size = getSizeOfType(var->type()->classScope->enumType, settings);
} else if (var->valueType()) {
size = ValueFlow::getSizeOf(*var->valueType(), settings);
} else if (!var->type()) {
size = getSizeOfType(var->typeStartToken(), settings);
}
// find the number of elements
size_t count = 1;
for (size_t i = 0; i < var->dimensions().size(); ++i) {
if (var->dimensionKnown(i))
count *= var->dimension(i);
else
count = 0;
}
if (size && count > 0) {
ValueFlow::Value value(count * size);
if (settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok, value, settings);
setTokenValue(tok->next(), value, settings);
}
}
} else if (tok2->tokType() == Token::eString) {
size_t sz = Token::getStrSize(tok2, settings);
if (sz > 0) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(const_cast<Token *>(tok->next()), value, settings);
}
} else if (tok2->tokType() == Token::eChar) {
nonneg int sz = 0;
if (cpp && settings->standards.cpp >= Standards::CPP20 && tok2->isUtf8())
sz = 1;
else if (tok2->isUtf16())
sz = 2;
else if (tok2->isUtf32())
sz = 4;
else if (tok2->isLong())
sz = settings->sizeof_wchar_t;
else if ((tok2->isCChar() && !cpp) || (tok2->isCMultiChar()))
sz = settings->sizeof_int;
else
sz = 1;
if (sz > 0) {
ValueFlow::Value value(sz);
value.setKnown();
setTokenValue(tok->next(), value, settings);
}
} else if (!tok2->type()) {
const ValueType &vt = ValueType::parseDecl(tok2,settings);
const size_t sz = ValueFlow::getSizeOf(vt, settings);
if (sz > 0) {
ValueFlow::Value value(sz);
if (!tok2->isTemplateArg() && settings->platformType != cppcheck::Platform::Unspecified)
value.setKnown();
setTokenValue(tok->next(), value, settings);
}
}
// skip over enum
tok = tok->linkAt(1);
}
return tok->next();
}
static void valueFlowNumber(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok;) {
tok = valueFlowSetConstantValue(tok, tokenlist->getSettings(), tokenlist->isCPP());
}
if (tokenlist->isCPP()) {
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->isName() && !tok->varId() && Token::Match(tok, "false|true")) {
ValueFlow::Value value(tok->str() == "true");
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, value, tokenlist->getSettings());
} else if (Token::Match(tok, "[(,] NULL [,)]")) {
// NULL function parameters are not simplified in the
// normal tokenlist
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok->next(), value, tokenlist->getSettings());
}
}
}
}
static void valueFlowString(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->tokType() == Token::eString) {
ValueFlow::Value strvalue;
strvalue.valueType = ValueFlow::Value::ValueType::TOK;
strvalue.tokvalue = tok;
strvalue.setKnown();
setTokenValue(tok, strvalue, tokenlist->getSettings());
}
}
}
static void valueFlowArray(TokenList *tokenlist)
{
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, value, tokenlist->getSettings());
}
// const array decl
else if (tok->variable() && tok->variable()->isArray() && tok->variable()->isConst() &&
tok->variable()->nameToken() == tok && Token::Match(tok, "%var% [ %num%| ] = {")) {
const 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, value, tokenlist->getSettings());
}
continue;
}
if (Token::Match(tok, "const %type% %var% [ %num%| ] = {")) {
const Token *vartok = tok->tokAt(2);
const Token *rhstok = vartok->next()->link()->tokAt(2);
constantArrays[vartok->varId()] = rhstok;
tok = rhstok->link();
continue;
}
else if (Token::Match(tok, "const char %var% [ %num%| ] = %str% ;")) {
const Token *vartok = tok->tokAt(2);
const Token *strtok = vartok->next()->link()->tokAt(2);
constantArrays[vartok->varId()] = strtok;
tok = strtok->next();
continue;
}
}
}
static bool isNonZero(const Token *tok)
{
return tok && (!tok->hasKnownIntValue() || tok->values().front().intvalue != 0);
}
static const Token *getOtherOperand(const Token *tok)
{
if (!tok)
return nullptr;
if (!tok->astParent())
return nullptr;
if (tok->astParent()->astOperand1() != tok)
return tok->astParent()->astOperand1();
if (tok->astParent()->astOperand2() != tok)
return tok->astParent()->astOperand2();
return nullptr;
}
static void valueFlowArrayBool(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
const Variable *var = nullptr;
bool known = false;
std::list<ValueFlow::Value>::const_iterator val =
std::find_if(tok->values().begin(), tok->values().end(), std::mem_fn(&ValueFlow::Value::isTokValue));
if (val == tok->values().end()) {
var = tok->variable();
known = true;
} else {
var = val->tokvalue->variable();
known = val->isKnown();
}
if (!var)
continue;
if (!var->isArray() || var->isArgument() || var->isStlType())
continue;
if (isNonZero(getOtherOperand(tok)) && Token::Match(tok->astParent(), "%comp%"))
continue;
// TODO: Check for function argument
if ((astIsBool(tok->astParent()) && !Token::Match(tok->astParent(), "(|%name%")) ||
(tok->astParent() && Token::Match(tok->astParent()->previous(), "if|while|for ("))) {
ValueFlow::Value value{1};
if (known)
value.setKnown();
setTokenValue(tok, value, tokenlist->getSettings());
}
}
}
static void valueFlowPointerAlias(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
// not address of
if (!tok->isUnaryOp("&"))
continue;
// parent should be a '='
if (!Token::simpleMatch(tok->astParent(), "="))
continue;
// child should be some buffer or variable
const Token *vartok = tok->astOperand1();
while (vartok) {
if (vartok->str() == "[")
vartok = vartok->astOperand1();
else if (vartok->str() == "." || vartok->str() == "::")
vartok = vartok->astOperand2();
else
break;
}
if (!(vartok && vartok->variable() && !vartok->variable()->isPointer()))
continue;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = tok;
setTokenValue(tok, value, tokenlist->getSettings());
}
}
static void valueFlowBitAnd(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->str() != "&")
continue;
if (tok->hasKnownValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
MathLib::bigint number;
if (MathLib::isInt(tok->astOperand1()->str()))
number = MathLib::toLongNumber(tok->astOperand1()->str());
else if (MathLib::isInt(tok->astOperand2()->str()))
number = MathLib::toLongNumber(tok->astOperand2()->str());
else
continue;
int bit = 0;
while (bit <= (MathLib::bigint_bits - 2) && ((((MathLib::bigint)1) << bit) < number))
++bit;
if ((((MathLib::bigint)1) << bit) == number) {
setTokenValue(tok, ValueFlow::Value(0), tokenlist->getSettings());
setTokenValue(tok, ValueFlow::Value(number), tokenlist->getSettings());
}
}
}
static void valueFlowSameExpressions(TokenList *tokenlist)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->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(), tokenlist->getSettings()->library, true, true, &val.errorPath)) {
setTokenValue(tok, val, tokenlist->getSettings());
}
}
}
static bool getExpressionRange(const Token *expr, MathLib::bigint *minvalue, MathLib::bigint *maxvalue)
{
if (expr->hasKnownIntValue()) {
if (minvalue)
*minvalue = expr->values().front().intvalue;
if (maxvalue)
*maxvalue = expr->values().front().intvalue;
return true;
}
if (expr->str() == "&" && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint vals[4];
bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
bool rhsHasKnownRange = getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]);
if (!lhsHasKnownRange && !rhsHasKnownRange)
return false;
if (!lhsHasKnownRange || !rhsHasKnownRange) {
if (minvalue)
*minvalue = lhsHasKnownRange ? vals[0] : vals[2];
if (maxvalue)
*maxvalue = lhsHasKnownRange ? vals[1] : vals[3];
} else {
if (minvalue)
*minvalue = vals[0] & vals[2];
if (maxvalue)
*maxvalue = vals[1] & vals[3];
}
return true;
}
if (expr->str() == "%" && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint vals[4];
if (!getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]))
return false;
if (vals[2] <= 0)
return false;
bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
if (lhsHasKnownRange && vals[0] < 0)
return false;
// If lhs has unknown value, it must be unsigned
if (!lhsHasKnownRange && (!expr->astOperand1()->valueType() || expr->astOperand1()->valueType()->sign != ValueType::Sign::UNSIGNED))
return false;
if (minvalue)
*minvalue = 0;
if (maxvalue)
*maxvalue = vals[3] - 1;
return true;
}
return false;
}
static void valueFlowRightShift(TokenList *tokenList, const Settings* settings)
{
for (Token *tok = tokenList->front(); tok; tok = tok->next()) {
if (tok->str() != ">>")
continue;
if (tok->hasKnownValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
if (!tok->astOperand2()->hasKnownValue())
continue;
const MathLib::bigint rhsvalue = tok->astOperand2()->values().front().intvalue;
if (rhsvalue < 0)
continue;
if (!tok->astOperand1()->valueType() || !tok->astOperand1()->valueType()->isIntegral())
continue;
if (!tok->astOperand2()->valueType() || !tok->astOperand2()->valueType()->isIntegral())
continue;
MathLib::bigint lhsmax=0;
if (!getExpressionRange(tok->astOperand1(), nullptr, &lhsmax))
continue;
if (lhsmax < 0)
continue;
int lhsbits;
if ((tok->astOperand1()->valueType()->type == ValueType::Type::CHAR) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::SHORT) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::WCHAR_T) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::BOOL) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::INT))
lhsbits = settings->int_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONG)
lhsbits = settings->long_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONGLONG)
lhsbits = settings->long_long_bit;
else
continue;
if (rhsvalue >= lhsbits || rhsvalue >= MathLib::bigint_bits || (1ULL << rhsvalue) <= lhsmax)
continue;
ValueFlow::Value val(0);
val.setKnown();
setTokenValue(tok, val, tokenList->getSettings());
}
}
static 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 void valueFlowImpossibleValues(TokenList* tokenList, const Settings* settings)
{
for (Token* tok = tokenList->front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
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, value, settings);
}
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, 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(), 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), 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(), value, settings);
} else if (tokenList->isCPP() && Token::simpleMatch(tok, "this")) {
ValueFlow::Value value{0};
value.setImpossible();
setTokenValue(tok, 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 = 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;
std::map<const Variable*, ValueFlow::Value>::const_iterator var = vars.find(tok->variable());
if (var == vars.end())
continue;
setTokenValue(tok, var->second, settings);
}
}
static void valueFlowGlobalStaticVar(TokenList *tokenList, const Settings *settings)
{
// Get variable values...
std::map<const Variable *, ValueFlow::Value> vars;
for (const Token *tok = tokenList->front(); tok; tok = tok->next()) {
if (!tok->variable())
continue;
// Initialization...
if (tok == tok->variable()->nameToken() &&
tok->variable()->isStatic() &&
!tok->variable()->isConst() &&
tok->valueType() &&
tok->valueType()->isIntegral() &&
tok->valueType()->pointer == 0 &&
tok->valueType()->constness == 0 &&
Token::Match(tok, "%name% =") &&
tok->next()->astOperand2() &&
tok->next()->astOperand2()->hasKnownIntValue()) {
vars[tok->variable()] = tok->next()->astOperand2()->values().front();
} else {
// If variable is written anywhere in TU then remove it from vars
if (!tok->astParent())
continue;
if (Token::Match(tok->astParent(), "++|--|&") && !tok->astParent()->astOperand2())
vars.erase(tok->variable());
else if (tok->astParent()->isAssignmentOp()) {
if (tok == tok->astParent()->astOperand1())
vars.erase(tok->variable());
else if (tokenList->isCPP() && Token::Match(tok->astParent()->tokAt(-2), "& %name% ="))
vars.erase(tok->variable());
} else if (isLikelyStreamRead(tokenList->isCPP(), tok->astParent())) {
vars.erase(tok->variable());
} else if (Token::Match(tok->astParent(), "[(,]"))
vars.erase(tok->variable());
}
}
// Set values..
for (Token *tok = tokenList->front(); tok; tok = tok->next()) {
if (!tok->variable())
continue;
std::map<const Variable *, ValueFlow::Value>::const_iterator var = vars.find(tok->variable());
if (var == vars.end())
continue;
setTokenValue(tok, var->second, settings);
}
}
static Analyzer::Result valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
TokenList* const tokenlist,
const Settings* settings);
static void valueFlowReverse(TokenList* tokenlist,
Token* tok,
const Token* const varToken,
ValueFlow::Value val,
ValueFlow::Value val2,
ErrorLogger* errorLogger,
const Settings* settings);
static bool isConditionKnown(const Token* tok, bool then)
{
const char* op = "||";
if (then)
op = "&&";
const Token* parent = tok->astParent();
while (parent && (parent->str() == op || parent->str() == "!"))
parent = parent->astParent();
return Token::Match(parent, "(|;");
}
static const std::string& invertAssign(const std::string& assign)
{
static std::unordered_map<std::string, std::string> lookup = {{"=", "="},
{"+=", "-="},
{"-=", "+="},
{"*=", "/="},
{"/=", "*="},
{"<<=", ">>="},
{">>=", "<<="},
{"^=", "^="}};
static std::string empty;
auto it = lookup.find(assign);
if (it == lookup.end())
return empty;
else
return it->second;
}
static std::string removeAssign(const std::string& assign) {
return std::string{assign.begin(), assign.end() - 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&, const U&)
{}
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;
}
template<class T>
struct SingleRange {
T* x;
T* begin() const {
return x;
}
T* end() const {
return x+1;
}
};
template<class T>
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 &;
explicit Iterator(const M::const_iterator &it)
: mIt(it) {}
reference operator*() const {
return mIt->second;
}
pointer operator->() {
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
for (const ValueFlow::Value &val : values) {
if (!val.isNonValue())
continue;
if (val.isInconclusive())
continue;
if (val.isLifetimeValue() && !val.isLocalLifetimeValue())
continue;
if (val.isLifetimeValue() && val.lifetimeKind != ValueFlow::Value::LifetimeKind::Address)
continue;
if (!Token::Match(val.tokvalue, ".|&|*|%var%"))
continue;
if (astHasVar(val.tokvalue, tok->varId()))
return true;
}
return false;
}
static 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 (Token::Match(tok, "%cop%"))
return bifurcate(tok->astOperand1(), varids, settings, depth) && bifurcate(tok->astOperand2(), varids, settings, depth);
if (Token::Match(tok, "%var%")) {
if (varids.count(tok->varId()) > 0)
return true;
const Variable* var = tok->variable();
if (!var)
return false;
const Token* start = var->declEndToken();
if (!start)
return false;
if (start->strAt(-1) == ")" || start->strAt(-1) == "}")
return false;
if (Token::Match(start, "; %varid% =", var->declarationId()))
start = start->tokAt(2);
if (var->isConst() || !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;
ProgramMemoryState pms;
ValueFlowAnalyzer() : tokenlist(nullptr), pms(nullptr) {}
explicit ValueFlowAnalyzer(const TokenList* t) : tokenlist(t), pms(tokenlist->getSettings()) {}
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*) 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;
}
virtual bool invalid() const {
return false;
}
bool isCPP() const {
return tokenlist->isCPP();
}
const Settings* getSettings() const {
return tokenlist->getSettings();
}
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;
} else if (tok->hasKnownIntValue() || tok->isLiteral()) {
result.dependent = false;
result.unknown = false;
return result;
} else 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;
} else 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.begin(), args.end(), [&](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;
} else {
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 {
Action read = Action::Read;
bool inconclusive = false;
if (isVariableChangedByFunctionCall(tok, getIndirect(tok), getSettings(), &inconclusive))
return read | Action::Invalid;
if (inconclusive)
return read | Action::Inconclusive;
if (isVariableChanged(tok, getIndirect(tok), getSettings(), isCPP())) {
if (Token::Match(tok->astParent(), "*|[|.|++|--"))
return read | Action::Invalid;
const ValueFlow::Value* value = getValue(tok);
// 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 = evaluate(Evaluate::Integral, tok->astParent()->astOperand2());
if (!result.empty() && value->equalTo(result.front()))
return Action::Idempotent;
}
return Action::Invalid;
}
return read;
}
virtual Action isAliasModified(const Token* tok) const {
// Lambda function call
if (Token::Match(tok, "%var% ("))
// TODO: Check if modified in the lambda function
return Action::Invalid;
int indirect = 0;
if (tok->valueType())
indirect = tok->valueType()->pointer;
if (isVariableChanged(tok, indirect, 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;
// Function cast does not modify global variables
} else if (tok->tokType() == Token::eType && astIsPrimitive(tok->next())) {
return Action::None;
} else if (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();
else
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) &&
parent->astOperand2()->hasKnownValue()) {
const Token* rhs = parent->astOperand2();
const ValueFlow::Value* rhsValue = rhs->getKnownValue(ValueFlow::Value::ValueType::INT);
Action a;
if (!rhsValue || !evalAssignment(*value, getAssign(parent, d), *rhsValue))
a = Action::Invalid;
else
a = Action::Write;
if (parent->str() != "=") {
a |= Action::Read;
} else {
if (rhsValue && !value->isImpossible() && value->equalValue(*rhsValue))
a = Action::Idempotent;
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 ValueFlow::Value* rhsValue =
tok->astParent()->astOperand2()->getKnownValue(ValueFlow::Value::ValueType::INT);
assert(rhsValue);
if (evalAssignment(*value, getAssign(tok->astParent(), d), *rhsValue)) {
const std::string info("Compound assignment '" + tok->astParent()->str() + "', assigned value is " +
value->infoString());
if (tok->astParent()->str() == "=")
value->errorPath.clear();
value->errorPath.emplace_back(tok, info);
} else {
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() == "++";
std::string opName(inc ? "incremented" : "decremented");
if (d == Direction::Reverse)
inc = !inc;
value->intvalue += (inc ? 1 : -1);
const std::string info(tok->str() + " is " + opName + "', new value is " + value->infoString());
value->errorPath.emplace_back(tok, info);
}
}
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().begin(), tok->values().end(), [&](const ValueFlow::Value& v) {
return v.isSymbolicValue() && currValue->equalValue(v);
}))
return false;
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)
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.begin(), v.errorPath.end());
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("*")) {
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 && match(lifeTok)) {
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;
}
return Action::None;
} else if (isAlias(ref, inconclusive)) {
inconclusive |= inconclusiveRef;
Action a = isAliasModified(tok);
if (inconclusive && a.isModified())
return Action::Inconclusive;
else
return a;
} else if (isSameSymbolicValue(ref)) {
return Action::Read | Action::SymbolicMatch;
}
return Action::None;
}
virtual Action analyze(const Token* tok, Direction d) const override {
if (invalid())
return Action::Invalid;
// Follow references
std::vector<ReferenceToken> refs = followAllReferences(tok);
const bool inconclusiveRefs = refs.size() != 1;
if (std::none_of(refs.begin(), refs.end(), [&](const ReferenceToken& ref) {
return tok == ref.token;
}))
refs.push_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;
}
virtual std::vector<MathLib::bigint> evaluate(Evaluate e, const Token* tok, const Token* ctx = nullptr) const override
{
if (e == Evaluate::Integral) {
if (tok->hasKnownIntValue())
return {static_cast<int>(tok->values().front().intvalue)};
std::vector<MathLib::bigint> result;
ProgramMemory pm = pms.get(tok, ctx, getProgramState());
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;
} else 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 {};
} else {
return {};
}
}
virtual 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();
pms.removeModifiedVars(endBlock);
if (state)
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 = state ? "true" : "false";
addErrorPath(tok, "Assuming condition is " + s);
}
}
if (!(flags & Assume::Absolute))
makeConditional();
}
virtual void internalUpdate(Token*, const ValueFlow::Value&, Direction)
{
assert(false && "Internal update unimplemented.");
}
virtual 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());
}
virtual ValuePtr<Analyzer> reanalyze(Token*, const std::string&) const override {
return {};
}
};
ValuePtr<Analyzer> makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList* tokenlist);
struct SingleValueFlowAnalyzer : ValueFlowAnalyzer {
std::unordered_map<nonneg int, const Variable*> varids;
std::unordered_map<nonneg int, const Variable*> aliases;
ValueFlow::Value value;
SingleValueFlowAnalyzer() : ValueFlowAnalyzer() {}
SingleValueFlowAnalyzer(const ValueFlow::Value& v, const TokenList* t) : ValueFlowAnalyzer(t), value(v) {}
const std::unordered_map<nonneg int, const Variable*>& getVars() const {
return varids;
}
const std::unordered_map<nonneg int, const Variable*>& getAliasedVars() const {
return aliases;
}
virtual const ValueFlow::Value* getValue(const Token*) const override {
return &value;
}
virtual ValueFlow::Value* getValue(const Token*) override {
return &value;
}
virtual void makeConditional() override {
value.conditional = true;
}
virtual bool useSymbolicValues() const override
{
if (value.isUninitValue())
return false;
if (value.isLifetimeValue())
return false;
return true;
}
virtual void addErrorPath(const Token* tok, const std::string& s) override {
value.errorPath.emplace_back(tok, s);
}
virtual 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 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;
}
virtual bool isGlobal() const override {
for (const auto&p:getVars()) {
const Variable* var = p.second;
if (!var->isLocal() && !var->isArgument() && !var->isConst())
return true;
}
return false;
}
virtual bool lowerToPossible() override {
if (value.isImpossible())
return false;
value.changeKnownToPossible();
return true;
}
virtual bool lowerToInconclusive() override {
if (value.isImpossible())
return false;
value.setInconclusive();
return true;
}
virtual bool isConditional() const override {
if (value.conditional)
return true;
if (value.condition)
return !value.isKnown() && !value.isImpossible();
return false;
}
virtual 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();
}
virtual bool updateScope(const Token* endBlock, bool) const override {
const Scope* scope = endBlock->scope();
if (!scope)
return false;
if (scope->type == Scope::eLambda) {
return value.isLifetimeValue();
} else if (scope->type == Scope::eIf || scope->type == Scope::eElse || scope->type == Scope::eWhile ||
scope->type == Scope::eFor) {
if (value.isKnown() || value.isImpossible())
return true;
if (value.isLifetimeValue())
return true;
if (isConditional())
return false;
const Token* condTok = getCondTokFromEnd(endBlock);
std::set<nonneg int> varids2;
std::transform(getVars().begin(), getVars().end(), std::inserter(varids2, varids2.begin()), SelectMapKeys{});
return bifurcate(condTok, varids2, getSettings());
}
return false;
}
virtual ValuePtr<Analyzer> reanalyze(Token* tok, const std::string& msg) const override {
ValueFlow::Value newValue = value;
newValue.errorPath.emplace_back(tok, msg);
return makeAnalyzer(tok, newValue, tokenlist);
}
};
struct ExpressionAnalyzer : SingleValueFlowAnalyzer {
const Token* expr;
bool local;
bool unknown;
bool dependOnThis;
ExpressionAnalyzer() : SingleValueFlowAnalyzer(), expr(nullptr), local(true), unknown(false), dependOnThis(false) {}
ExpressionAnalyzer(const Token* e, const ValueFlow::Value& val, const TokenList* t)
: SingleValueFlowAnalyzer(val, t), expr(e), local(true), unknown(false), dependOnThis(false) {
assert(e && e->exprId() != 0 && "Not a valid expression");
dependOnThis = exprDependsOnThis(expr);
setupExprVarIds(expr);
if (val.isSymbolicValue())
setupExprVarIds(val.tokvalue);
}
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) {
const 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->varId() == 0 && !tok->function() && tok->isName() && tok->previous()->str() != ".") {
// unknown variable
unknown = true;
return ChildrenToVisit::none;
}
if (tok->varId() > 0) {
varids[tok->varId()] = tok->variable();
if (!Token::simpleMatch(tok->previous(), ".")) {
const Variable* var = tok->variable();
if (var && var->isReference() && var->isLocal() && Token::Match(var->nameToken(), "%var% [=(]") &&
!isGlobalData(var->nameToken()->next()->astOperand2(), isCPP()))
return ChildrenToVisit::none;
const bool deref = tok->astParent() &&
(tok->astParent()->isUnaryOp("*") ||
(tok->astParent()->str() == "[" && tok == tok->astParent()->astOperand1()));
local &= !nonLocal(tok->variable(), deref);
}
}
return ChildrenToVisit::op1_and_op2;
});
}
virtual bool invalid() const override {
return unknown;
}
virtual ProgramState getProgramState() const override {
ProgramState ps;
ps[expr] = value;
return ps;
}
virtual bool match(const Token* tok) const override {
return tok->exprId() == expr->exprId();
}
virtual bool dependsOnThis() const override {
return dependOnThis;
}
virtual bool isGlobal() const override {
return !local;
}
virtual bool isVariable() const override {
return expr->varId() > 0;
}
};
struct OppositeExpressionAnalyzer : ExpressionAnalyzer {
bool isNot;
OppositeExpressionAnalyzer() : ExpressionAnalyzer(), isNot(false) {}
OppositeExpressionAnalyzer(bool pIsNot, const Token* e, const ValueFlow::Value& val, const TokenList* t)
: ExpressionAnalyzer(e, val, t), isNot(pIsNot)
{}
virtual 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() : ExpressionAnalyzer(), partialReads(nullptr) {}
SubExpressionAnalyzer(const Token* e, const ValueFlow::Value& val, const TokenList* t)
: ExpressionAnalyzer(e, val, t), partialReads(std::make_shared<PartialReadContainer>())
{}
virtual bool submatch(const Token* tok, bool exact = true) const = 0;
virtual 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);
}
virtual bool match(const Token* tok) const override
{
return tok->astOperand1() && tok->astOperand1()->exprId() == expr->exprId() && submatch(tok);
}
virtual bool internalMatch(const Token* tok) const override
{
return tok->exprId() == expr->exprId() && !(astIsLHS(tok) && submatch(tok->astParent(), false));
}
virtual void internalUpdate(Token* tok, const ValueFlow::Value& v, Direction) override
{
partialReads->push_back(std::make_pair(tok, v));
}
// No reanalysis for subexression
virtual ValuePtr<Analyzer> reanalyze(Token*, const std::string&) const override {
return {};
}
};
struct MemberExpressionAnalyzer : SubExpressionAnalyzer {
std::string varname;
MemberExpressionAnalyzer() : SubExpressionAnalyzer(), varname() {}
MemberExpressionAnalyzer(std::string varname, const Token* e, const ValueFlow::Value& val, const TokenList* t)
: SubExpressionAnalyzer(e, val, t), varname(std::move(varname))
{}
virtual 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;
}
};
static Analyzer::Result valueFlowForwardExpression(Token* startToken,
const Token* endToken,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
const TokenList* const tokenlist,
const Settings* settings)
{
Analyzer::Result result{};
for (const ValueFlow::Value& v : values) {
ExpressionAnalyzer a(exprTok, v, tokenlist);
result.update(valueFlowGenericForward(startToken, endToken, a, settings));
}
return result;
}
static const Token* parseBinaryIntOp(const Token* expr, MathLib::bigint& known)
{
if (!expr)
return nullptr;
if (!expr->astOperand1() || !expr->astOperand2())
return nullptr;
if (expr->astOperand1()->exprId() == 0 && !expr->astOperand1()->hasKnownIntValue())
return nullptr;
if (expr->astOperand2()->exprId() == 0 && !expr->astOperand2()->hasKnownIntValue())
return nullptr;
const Token* knownTok = nullptr;
const Token* varTok = nullptr;
if (expr->astOperand1()->hasKnownIntValue() && !expr->astOperand2()->hasKnownIntValue()) {
varTok = expr->astOperand2();
knownTok = expr->astOperand1();
} else if (expr->astOperand2()->hasKnownIntValue() && !expr->astOperand1()->hasKnownIntValue()) {
varTok = expr->astOperand1();
knownTok = expr->astOperand2();
}
if (knownTok)
known = knownTok->values().front().intvalue;
return varTok;
}
static const Token* solveExprValue(const Token* expr, 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, intval);
bool rhs = astIsRHS(binaryTok);
// If its on the rhs, then -1 multipllication is needed, which is not possible with simple delta analysis used currentl 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 solveExprValue(binaryTok, value);
}
case '-': {
if (rhs)
value.intvalue = intval - value.intvalue;
else
value.intvalue += intval;
return solveExprValue(binaryTok, value);
}
case '*': {
if (intval == 0)
break;
value.intvalue /= intval;
return solveExprValue(binaryTok, value);
}
case '^': {
value.intvalue ^= intval;
return solveExprValue(binaryTok, value);
}
}
}
return expr;
}
ValuePtr<Analyzer> makeAnalyzer(const Token* exprTok, ValueFlow::Value value, const TokenList* tokenlist)
{
const Token* expr = solveExprValue(exprTok, value);
return ExpressionAnalyzer(expr, value, tokenlist);
}
static Analyzer::Result valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
TokenList* const tokenlist,
const Settings* settings)
{
Analyzer::Result result{};
for (const ValueFlow::Value& v : values) {
result.update(valueFlowGenericForward(startToken, endToken, makeAnalyzer(exprTok, v, tokenlist), settings));
}
return result;
}
static Analyzer::Result valueFlowForward(Token* top,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* const tokenlist,
const Settings* settings)
{
Analyzer::Result result{};
for (const ValueFlow::Value& v : values) {
result.update(valueFlowGenericForward(top, makeAnalyzer(exprTok, v, tokenlist), settings));
}
return result;
}
static void valueFlowReverse(Token* tok,
const Token* const endToken,
const Token* const varToken,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings)
{
for (const ValueFlow::Value& v : values) {
ExpressionAnalyzer a(varToken, v, tokenlist);
valueFlowGenericReverse(tok, endToken, a, settings);
}
}
static void valueFlowReverse(TokenList* tokenlist,
Token* tok,
const Token* const varToken,
ValueFlow::Value val,
ValueFlow::Value val2,
ErrorLogger* /*errorLogger*/,
const Settings* settings)
{
std::list<ValueFlow::Value> values = {val};
if (val2.varId != 0)
values.push_back(val2);
valueFlowReverse(tok, nullptr, varToken, values, tokenlist, settings);
}
std::string lifetimeType(const Token *tok, const ValueFlow::Value *val)
{
std::string result;
if (!val)
return "object";
switch (val->lifetimeKind) {
case ValueFlow::Value::LifetimeKind::Lambda:
result = "lambda";
break;
case ValueFlow::Value::LifetimeKind::Iterator:
result = "iterator";
break;
case ValueFlow::Value::LifetimeKind::Object:
case ValueFlow::Value::LifetimeKind::SubObject:
case ValueFlow::Value::LifetimeKind::Address:
if (astIsPointer(tok))
result = "pointer";
else
result = "object";
break;
}
return result;
}
std::string lifetimeMessage(const Token *tok, const ValueFlow::Value *val, ErrorPath &errorPath)
{
const Token *tokvalue = val ? val->tokvalue : nullptr;
const Variable *tokvar = tokvalue ? tokvalue->variable() : nullptr;
const Token *vartok = tokvar ? tokvar->nameToken() : nullptr;
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();
std::string submessage;
if (var) {
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> 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().begin(), tok->values().end(), std::back_inserter(result), pred);
return result;
}
ValueFlow::Value getLifetimeObjValue(const Token *tok, bool inconclusive)
{
std::vector<ValueFlow::Value> values = 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<LifetimeToken> getLifetimeTokens(const Token* tok,
bool escape,
ValueFlow::Value::ErrorPath errorPath,
Predicate pred,
int depth = 20)
{
if (!tok)
return std::vector<LifetimeToken> {};
if (Token::simpleMatch(tok, "..."))
return std::vector<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()) {
if (!var->declEndToken())
return {{tok, true, std::move(errorPath)}};
if (var->isArgument()) {
errorPath.emplace_back(var->declEndToken(), "Passed to reference.");
return {{tok, true, std::move(errorPath)}};
} else if (Token::simpleMatch(var->declEndToken(), "=")) {
errorPath.emplace_back(var->declEndToken(), "Assigned to reference.");
const Token *vartok = var->declEndToken()->astOperand2();
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);
else
return std::vector<LifetimeToken>{};
} else {
return std::vector<LifetimeToken> {};
}
}
} else if (Token::Match(tok->previous(), "%name% (")) {
const Function *f = tok->previous()->function();
if (f) {
if (!Function::returnsReference(f))
return {{tok, std::move(errorPath)}};
std::vector<LifetimeToken> result;
std::vector<const Token*> returns = Function::findReturns(f);
for (const Token* returnTok : returns) {
if (returnTok == tok)
continue;
for (LifetimeToken& lt : getLifetimeTokens(returnTok, escape, errorPath, pred, depth - returns.size())) {
const Token* argvarTok = lt.token;
const Variable* argvar = argvarTok->variable();
if (!argvar)
continue;
if (argvar->isArgument() && (argvar->isReference() || argvar->isRValueReference())) {
int n = getArgumentPos(argvar, f);
if (n < 0)
return std::vector<LifetimeToken> {};
std::vector<const Token*> args = getArguments(tok->previous());
// TODO: Track lifetimes of default parameters
if (n >= args.size())
return std::vector<LifetimeToken> {};
const Token* argTok = args[n];
lt.errorPath.emplace_back(returnTok, "Return reference.");
lt.errorPath.emplace_back(tok->previous(), "Called function passing '" + argTok->expressionString() + "'.");
std::vector<LifetimeToken> arglts = LifetimeToken::setInconclusive(
getLifetimeTokens(argTok, escape, std::move(lt.errorPath), pred, depth - returns.size()),
returns.size() > 1);
result.insert(result.end(), arglts.begin(), arglts.end());
}
}
}
return result;
} else if (Token::Match(tok->tokAt(-2), ". %name% (") && tok->tokAt(-2)->originalName() != "->" && astIsContainer(tok->tokAt(-2)->astOperand1())) {
const Library::Container* library = getLibraryContainer(tok->tokAt(-2)->astOperand1());
Library::Container::Yield y = library->getYield(tok->previous()->str());
if (y == Library::Container::Yield::AT_INDEX || y == Library::Container::Yield::ITEM) {
errorPath.emplace_back(tok->previous(), "Accessing container.");
return LifetimeToken::setAddressOf(
getLifetimeTokens(tok->tokAt(-2)->astOperand1(), escape, std::move(errorPath), pred, depth - 1),
false);
}
}
} else if (Token::Match(tok, ".|::|[") || tok->isUnaryOp("*")) {
const Token *vartok = tok;
if (tok->isUnaryOp("*"))
vartok = tok->astOperand1();
while (vartok) {
if (vartok->str() == "[" || vartok->originalName() == "->")
vartok = vartok->astOperand1();
else if (vartok->str() == "." || vartok->str() == "::")
vartok = vartok->astOperand2();
else
break;
}
if (!vartok)
return {{tok, std::move(errorPath)}};
const Variable *tokvar = vartok->variable();
const bool isContainer = astIsContainer(vartok) && !astIsPointer(vartok);
if (!astIsUniqueSmartPointer(vartok) && !isContainer && !(tokvar && tokvar->isArray() && !tokvar->isArgument()) &&
(Token::Match(vartok->astParent(), "[|*") || vartok->astParent()->originalName() == "->")) {
for (const ValueFlow::Value &v : vartok->values()) {
if (!v.isLocalLifetimeValue())
continue;
if (v.tokvalue == tok)
continue;
errorPath.insert(errorPath.end(), v.errorPath.begin(), v.errorPath.end());
return getLifetimeTokens(v.tokvalue, escape, std::move(errorPath), pred, depth - 1);
}
} else {
return LifetimeToken::setAddressOf(getLifetimeTokens(vartok, escape, std::move(errorPath), pred, depth - 1),
!(astIsContainer(vartok) && Token::simpleMatch(vartok->astParent(), "[")));
}
}
return {{tok, std::move(errorPath)}};
}
std::vector<LifetimeToken> getLifetimeTokens(const Token* tok, bool escape, ValueFlow::Value::ErrorPath errorPath)
{
return getLifetimeTokens(tok, escape, std::move(errorPath), [](const Token*) {
return false;
});
}
bool 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<LifetimeToken> lts = getLifetimeTokens(tok);
if (lts.size() != 1)
return nullptr;
if (lts.front().inconclusive)
return nullptr;
if (addressOf)
*addressOf = lts.front().addressOf;
errorPath.insert(errorPath.end(), lts.front().errorPath.begin(), lts.front().errorPath.end());
return lts.front().token;
}
const Variable* getLifetimeVariable(const Token* tok, ValueFlow::Value::ErrorPath& errorPath, bool* addressOf)
{
const Token* tok2 = getLifetimeToken(tok, errorPath, addressOf);
if (tok2 && tok2->variable())
return tok2->variable();
return nullptr;
}
const Variable* getLifetimeVariable(const Token* tok)
{
ValueFlow::Value::ErrorPath errorPath;
return getLifetimeVariable(tok, errorPath, nullptr);
}
static bool isNotLifetimeValue(const ValueFlow::Value& val)
{
return !val.isLifetimeValue();
}
static bool isLifetimeOwned(const ValueType* 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 (!vt) {
if (isLifetimeOwned(vtParent))
return true;
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;
if (vtParent->pointer == vt->pointer && vtParent->type == vt->type && vtParent->isIntegral())
// sign conversion
return true;
}
return false;
}
static const Token* skipCVRefs(const Token* tok, const Token* endTok)
{
while (tok != endTok && Token::Match(tok, "const|volatile|auto|&|&&"))
tok = tok->next();
return tok;
}
static bool isNotEqual(std::pair<const Token*, const Token*> x, std::pair<const Token*, const Token*> y)
{
const Token* start1 = x.first;
const Token* start2 = y.first;
if (start1 == nullptr || start2 == nullptr)
return false;
while (start1 != x.second && start2 != y.second) {
const Token* tok1 = skipCVRefs(start1, x.second);
if (tok1 != start1) {
start1 = tok1;
continue;
}
const Token* tok2 = skipCVRefs(start2, y.second);
if (tok2 != start2) {
start2 = tok2;
continue;
}
if (start1->str() != start2->str())
return true;
start1 = start1->next();
start2 = start2->next();
}
start1 = skipCVRefs(start1, x.second);
start2 = skipCVRefs(start2, y.second);
return !(start1 == x.second && start2 == y.second);
}
static bool isNotEqual(std::pair<const Token*, const Token*> x, const std::string& y)
{
TokenList tokenList(nullptr);
std::istringstream istr(y);
tokenList.createTokens(istr);
return isNotEqual(x, std::make_pair(tokenList.front(), tokenList.back()));
}
static bool isNotEqual(std::pair<const Token*, const Token*> x, const ValueType* y)
{
if (y == nullptr)
return false;
if (y->originalTypeName.empty())
return false;
return isNotEqual(x, y->originalTypeName);
}
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;
}
static std::vector<ValueType> getParentValueTypes(const Token* tok, const Settings* settings = nullptr)
{
if (!tok)
return {};
if (!tok->astParent())
return {};
if (Token::Match(tok->astParent(), "(|{|,")) {
int argn = -1;
const Token* ftok = getTokenArgumentFunction(tok, argn);
if (ftok && ftok->function()) {
std::vector<ValueType> result;
std::vector<const Variable*> argsVars = getArgumentVars(ftok, argn);
for (const Variable* var : getArgumentVars(ftok, argn)) {
if (!var)
continue;
if (!var->valueType())
continue;
result.push_back(*var->valueType());
}
return result;
}
}
if (settings && Token::Match(tok->astParent()->tokAt(-2), ". push_back|push_front|insert|push (") &&
astIsContainer(tok->astParent()->tokAt(-2)->astOperand1())) {
const Token* contTok = tok->astParent()->tokAt(-2)->astOperand1();
const ValueType* vtCont = contTok->valueType();
if (!vtCont->containerTypeToken)
return {};
ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings);
return {std::move(vtParent)};
}
if (tok->astParent()->valueType())
return {*tok->astParent()->valueType()};
return {};
}
bool isLifetimeBorrowed(const Token *tok, const Settings *settings)
{
if (!tok)
return true;
if (tok->str() == ",")
return true;
if (!tok->astParent())
return true;
if (!Token::Match(tok->astParent()->previous(), "%name% (") && !Token::simpleMatch(tok->astParent(), ",")) {
if (!Token::simpleMatch(tok, "{")) {
const ValueType *vt = tok->valueType();
const ValueType *vtParent = tok->astParent()->valueType();
if (isLifetimeBorrowed(vt, vtParent))
return true;
if (isLifetimeOwned(vt, vtParent))
return false;
}
if (Token::Match(tok->astParent(), "return|(|{|%assign%")) {
if (isDifferentType(tok, tok->astParent()))
return false;
}
} else if (Token::Match(tok->astParent()->tokAt(-3), "%var% . push_back|push_front|insert|push (") &&
astIsContainer(tok->astParent()->tokAt(-3))) {
const ValueType *vt = tok->valueType();
const ValueType *vtCont = tok->astParent()->tokAt(-3)->valueType();
if (!vtCont->containerTypeToken)
return true;
ValueType vtParent = ValueType::parseDecl(vtCont->containerTypeToken, settings);
if (isLifetimeBorrowed(vt, &vtParent))
return true;
if (isLifetimeOwned(vt, &vtParent))
return false;
}
return true;
}
static void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings);
static void valueFlowLifetimeConstructor(Token *tok,
TokenList *tokenlist,
ErrorLogger *errorLogger,
const Settings *settings);
static 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->isLocal())
return innerScope->bodyEnd->next();
return innerScope->bodyEnd;
}
const Token* 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;
}
}
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% {")) {
std::list<ValueFlow::Value> values = tok->values();
values.remove_if(&isNotLifetimeValue);
valueFlowForward(nextAfterAstRightmostLeaf(tok), 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 (!isLifetimeBorrowed(parent->astOperand2(), settings))
return;
const Token* expr = getLHSVariableToken(parent);
const Token* endOfVarScope = getEndOfExprScope(expr);
// Only forward lifetime values
std::list<ValueFlow::Value> values = parent->astOperand2()->values();
values.remove_if(&isNotLifetimeValue);
// Skip RHS
const Token *nextExpression = nextAfterAstRightmostLeaf(parent);
if (expr->exprId() > 0) {
valueFlowForwardExpression(const_cast<Token*>(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(const_cast<Token*>(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()) {
const Variable *var = tok->variable();
const Token *endOfVarScope = var->scope()->bodyEnd;
std::list<ValueFlow::Value> values = tok->values();
const Token *nextExpression = nextAfterAstRightmostLeaf(parent);
// Only forward lifetime values
values.remove_if(&isNotLifetimeValue);
valueFlowForward(const_cast<Token*>(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 (const ValueFlow::Value& value:values)
setTokenValue(parent, value, tokenlist->getSettings());
valueFlowForwardLifetime(parent, tokenlist, errorLogger, settings);
}
}
struct LifetimeStore {
const Token *argtok;
std::string message;
ValueFlow::Value::LifetimeKind type;
ErrorPath errorPath;
bool inconclusive;
bool forward;
struct Context {
Token* tok;
TokenList* tokenlist;
ErrorLogger* errorLogger;
const Settings* settings;
};
LifetimeStore()
: argtok(nullptr), message(), type(), errorPath(), inconclusive(false), forward(true), mContext(nullptr)
{}
LifetimeStore(const Token* argtok,
const std::string& message,
ValueFlow::Value::LifetimeKind type = ValueFlow::Value::LifetimeKind::Object,
bool inconclusive = false)
: argtok(argtok),
message(message),
type(type),
errorPath(),
inconclusive(inconclusive),
forward(true),
mContext(nullptr)
{}
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, Token *tok, const Variable *var, TokenList *tokenlist, ErrorLogger *errorLogger) {
if (!var)
return LifetimeStore{};
if (!var->isArgument())
return LifetimeStore{};
int n = getArgumentPos(var, f);
if (n < 0)
return LifetimeStore{};
std::vector<const Token *> args = getArguments(tok);
if (n >= args.size()) {
if (tokenlist->getSettings()->debugwarnings)
bailout(tokenlist,
errorLogger,
tok,
"Argument mismatch: Function '" + tok->str() + "' returning lifetime from argument index " +
std::to_string(n) + " but only " + std::to_string(args.size()) +
" arguments are available.");
return LifetimeStore{};
}
const Token *argtok2 = args[n];
return LifetimeStore{argtok2, "Passed to '" + tok->expressionString() + "'.", ValueFlow::Value::LifetimeKind::Object};
}
template<class Predicate>
bool byRef(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings, Predicate pred) const {
if (!argtok)
return false;
bool update = false;
for (const LifetimeToken& lt : getLifetimeTokens(argtok)) {
if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive)
continue;
ErrorPath er = errorPath;
er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end());
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().begin(), tok->values().end(), value) != tok->values().end())
return false;
setTokenValue(tok, value, tokenlist->getSettings());
update = true;
}
if (update && forward)
forwardLifetime(tok, tokenlist, errorLogger, settings);
return update;
}
bool byRef(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings) const {
return byRef(tok, tokenlist, errorLogger, settings, [](const Token*) {
return true;
});
}
template<class Predicate>
bool byVal(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings, Predicate pred) const {
if (!argtok)
return false;
bool update = false;
if (argtok->values().empty()) {
ErrorPath er;
er.emplace_back(argtok, message);
for (const LifetimeToken& lt : 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.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().begin(), tok->values().end(), value) != tok->values().end())
continue;
;
setTokenValue(tok, value, tokenlist->getSettings());
update = true;
}
}
for (const ValueFlow::Value &v : argtok->values()) {
if (!v.isLifetimeValue())
continue;
const Token *tok3 = v.tokvalue;
for (const LifetimeToken& lt : getLifetimeTokens(tok3)) {
if (!settings->certainty.isEnabled(Certainty::inconclusive) && lt.inconclusive)
continue;
ErrorPath er = v.errorPath;
er.insert(er.end(), lt.errorPath.begin(), lt.errorPath.end());
if (!lt.token)
return false;
if (!pred(lt.token))
return false;
er.emplace_back(argtok, message);
er.insert(er.end(), errorPath.begin(), errorPath.end());
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.lifetimeScope = v.lifetimeScope;
value.path = v.path;
value.tokvalue = lt.token;
value.errorPath = std::move(er);
value.lifetimeKind = type;
value.setInconclusive(lt.inconclusive || v.isInconclusive() || inconclusive);
// Don't add the value a second time
if (std::find(tok->values().begin(), tok->values().end(), value) != tok->values().end())
continue;
setTokenValue(tok, value, tokenlist->getSettings());
update = true;
}
}
if (update && forward)
forwardLifetime(tok, tokenlist, errorLogger, settings);
return update;
}
bool byVal(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings) const {
return byVal(tok, tokenlist, errorLogger, settings, [](const Token*) {
return true;
});
}
template<class Predicate>
void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings, Predicate pred) const {
if (!settings->certainty.isEnabled(Certainty::inconclusive) && inconclusive)
return;
if (!argtok)
return;
for (const ValueFlow::Value &v : argtok->values()) {
if (!v.isLifetimeValue())
continue;
const Token *tok2 = v.tokvalue;
ErrorPath er = v.errorPath;
const Variable *var = getLifetimeVariable(tok2, er);
er.insert(er.end(), errorPath.begin(), errorPath.end());
if (!var)
continue;
for (const Token *tok3 = tok; tok3 && tok3 != var->declEndToken(); tok3 = tok3->previous()) {
if (tok3->varId() == var->declarationId()) {
LifetimeStore{tok3, message, type, inconclusive}.byVal(tok, tokenlist, errorLogger, settings, pred);
break;
}
}
}
}
void byDerefCopy(Token *tok, TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings) const {
byDerefCopy(tok, tokenlist, errorLogger, settings, [](const Token *) {
return true;
});
}
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 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();
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(), 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);
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() && 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 (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 = getLifetimeVariable(returnTok);
if (returnVar && returnVar->isArgument() && (returnVar->isConst() || !isVariableChanged(returnVar, settings, tokenlist->isCPP()))) {
LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, returnVar, tokenlist, 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) + ".");
if (v.lifetimeScope == ValueFlow::Value::LifetimeScope::ThisValue)
update |= ls.byVal(tok->next(), tokenlist, errorLogger, settings);
else
update |= ls.byRef(tok->next(), tokenlist, errorLogger, settings);
continue;
}
const Variable *var = v.tokvalue->variable();
LifetimeStore ls = LifetimeStore::fromFunctionArg(f, tok, var, tokenlist, 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, tokenlist, errorLogger, settings);
valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings);
}
}
static void valueFlowLifetimeConstructor(Token* tok,
const Type* t,
TokenList* tokenlist,
ErrorLogger* errorLogger,
const Settings* settings)
{
if (!Token::Match(tok, "(|{"))
return;
if (!t) {
if (tok->valueType() && tok->valueType()->type != ValueType::RECORD)
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;
// Only support aggregate constructors for now
if (scope->numConstructors == 0 && t->derivedFrom.empty() && (t->isClassType() || t->isStructType())) {
std::vector<const Token*> args = getArguments(tok);
auto it = scope->varlist.begin();
LifetimeStore::forEach(args,
"Passed to constructor of '" + t->name() + "'.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
if (it == scope->varlist.end())
return;
const Variable& var = *it;
if (var.isReference() || var.isRValueReference()) {
ls.byRef(tok, tokenlist, errorLogger, settings);
} else {
ls.byVal(tok, tokenlist, errorLogger, settings);
}
it++;
});
}
}
static bool hasInitList(const Token* tok)
{
if (astIsPointer(tok))
return true;
if (astIsContainer(tok)) {
const Library::Container * library = getLibraryContainer(tok);
if (!library)
return false;
return library->hasInitializerListConstructor;
}
return false;
}
static void valueFlowLifetimeConstructor(Token* tok, TokenList* tokenlist, ErrorLogger* errorLogger, const Settings* settings)
{
if (!Token::Match(tok, "(|{"))
return;
Token* parent = tok->astParent();
while (Token::simpleMatch(parent, ","))
parent = parent->astParent();
if (Token::Match(tok, "{|(") && astIsContainerView(tok) && !tok->function()) {
std::vector<const Token*> args = getArguments(tok);
if (args.size() == 1 && astIsContainerOwned(args.front())) {
LifetimeStore{args.front(), "Passed to container view.", ValueFlow::Value::LifetimeKind::SubObject}.byRef(
tok, tokenlist, errorLogger, settings);
}
} else if (Token::simpleMatch(parent, "{") && hasInitList(parent->astParent())) {
valueFlowLifetimeConstructor(tok, Token::typeOf(parent->previous()), tokenlist, errorLogger, settings);
} else if (Token::simpleMatch(tok, "{") && hasInitList(parent)) {
std::vector<const Token *> args = getArguments(tok);
// Assume range constructor if passed a pair of iterators
if (astIsContainer(parent) && args.size() == 2 && astIsIterator(args[0]) && astIsIterator(args[1])) {
LifetimeStore::forEach(
args, "Passed to initializer list.", ValueFlow::Value::LifetimeKind::SubObject, [&](const LifetimeStore& ls) {
ls.byDerefCopy(tok, tokenlist, errorLogger, settings);
});
} else {
LifetimeStore::forEach(args,
"Passed to initializer list.",
ValueFlow::Value::LifetimeKind::SubObject,
[&](const LifetimeStore& ls) {
ls.byVal(tok, tokenlist, errorLogger, settings);
});
}
} else {
valueFlowLifetimeConstructor(tok, Token::typeOf(tok->previous()), tokenlist, errorLogger, settings);
}
}
struct Lambda {
enum class Capture {
Undefined,
ByValue,
ByReference
};
explicit Lambda(const Token * tok)
: capture(nullptr), arguments(nullptr), returnTok(nullptr), bodyTok(nullptr), explicitCaptures(), implicitCapture(Capture::Undefined) {
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, Capture::ByReference);
} else if (Token::simpleMatch(c, "* this")) {
explicitCaptures[c->next()->variable()] = std::make_pair(c->next(), Capture::ByValue);
} else if (c->variable()) {
explicitCaptures[c->variable()] = std::make_pair(c, Capture::ByValue);
} else if (c->isUnaryOp("&") && Token::Match(c->astOperand1(), "%var%")) {
explicitCaptures[c->astOperand1()->variable()] = std::make_pair(c->astOperand1(), Capture::ByReference);
} else {
const std::string& s = c->expressionString();
if (s == "=")
implicitCapture = Capture::ByValue;
else if (s == "&")
implicitCapture = Capture::ByReference;
}
}
}
const Token * capture;
const Token * arguments;
const Token * returnTok;
const Token * bodyTok;
std::unordered_map<const Variable*, std::pair<const Token*, Capture>> explicitCaptures;
Capture implicitCapture;
std::vector<const Token*> getCaptures() {
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.begin(), vtParents.end(), [&](const ValueType& vt) {
if (!vt.container)
return false;
return vt.container->view;
});
}
static void valueFlowLifetime(TokenList *tokenlist, SymbolDatabase*, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->scope())
continue;
if (tok->scope()->type == Scope::eGlobal)
continue;
Lambda lam(tok);
// Lamdas
if (lam.isLambda()) {
const Scope * bodyScope = lam.bodyTok->scope();
std::set<const Scope *> scopes;
// 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;
// cppcheck-suppress varid0
auto captureVariable = [&](const Token* tok2, Lambda::Capture c, std::function<bool(const Token*)> pred) {
if (varids.count(tok->varId()) > 0)
return;
ErrorPath errorPath;
if (c == Lambda::Capture::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 == Lambda::Capture::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, Lambda::Capture c) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
if (c == Lambda::Capture::ByReference)
value.lifetimeScope = ValueFlow::Value::LifetimeScope::ThisPointer;
else if (c == Lambda::Capture::ByValue)
value.lifetimeScope = ValueFlow::Value::LifetimeScope::ThisValue;
value.tokvalue = tok2;
value.errorPath.push_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().begin(), tok->values().end(), value) != tok->values().end())
return;
setTokenValue(tok, value, tokenlist->getSettings());
update |= true;
};
// Handle explicit capture
for (const auto& p:lam.explicitCaptures) {
const Variable* var = p.first;
const Token* tok2 = p.second.first;
Lambda::Capture 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;
} else 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);
} else 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, Lambda::Capture::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 LifetimeToken& lt : 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, value, tokenlist->getSettings());
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 (!Token::Match(parent, ". %name% ("))
continue;
bool isContainerOfPointers = true;
const Token* containerTypeToken = tok->valueType()->containerTypeToken;
if (containerTypeToken) {
ValueType vt = ValueType::parseDecl(containerTypeToken, settings);
isContainerOfPointers = vt.pointer > 0;
}
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 ((astIsPointer(parent->tokAt(2)) && !isContainerOfPointers) ||
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.isLifetimeValue())
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.begin(), rt.errors.end());
setTokenValue(parent->tokAt(2), value, tokenlist->getSettings());
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|%type%|%var% {")) {
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, value, tokenlist->getSettings());
valueFlowForwardLifetime(ptok, tokenlist, errorLogger, settings);
}
// Check variables
else if (tok->variable()) {
ErrorPath errorPath;
const Variable * var = getLifetimeVariable(tok, errorPath);
if (!var)
continue;
if (var->nameToken() == tok)
continue;
if (var->isArray() && !var->isStlType() && !var->isArgument() && isDecayedPointer(tok)) {
errorPath.emplace_back(tok, "Array decayed to pointer here.");
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::LIFETIME;
value.lifetimeScope = ValueFlow::Value::LifetimeScope::Local;
value.tokvalue = var->nameToken();
value.errorPath = errorPath;
setTokenValue(tok, value, tokenlist->getSettings());
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
// Forward any lifetimes
else if (std::any_of(tok->values().begin(), tok->values().end(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) {
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
}
}
}
static bool isStdMoveOrStdForwarded(Token * tok, ValueFlow::Value::MoveKind * moveKind, Token ** varTok = nullptr)
{
if (tok->str() != "std")
return false;
ValueFlow::Value::MoveKind kind = ValueFlow::Value::MoveKind::NonMovedVariable;
Token * variableToken = nullptr;
if (Token::Match(tok, "std :: move ( %var% )")) {
variableToken = tok->tokAt(4);
kind = ValueFlow::Value::MoveKind::MovedVariable;
} else if (Token::simpleMatch(tok, "std :: forward <")) {
const Token * const leftAngle = tok->tokAt(3);
Token * rightAngle = leftAngle->link();
if (Token::Match(rightAngle, "> ( %var% )")) {
variableToken = rightAngle->tokAt(2);
kind = ValueFlow::Value::MoveKind::ForwardedVariable;
}
}
if (!variableToken)
return false;
if (variableToken->strAt(2) == ".") // Only partially moved
return false;
if (variableToken->valueType() && variableToken->valueType()->type >= ValueType::Type::VOID)
return false;
if (moveKind != nullptr)
*moveKind = kind;
if (varTok != nullptr)
*varTok = variableToken;
return true;
}
static bool isOpenParenthesisMemberFunctionCallOfVarId(const Token * openParenthesisToken, nonneg int varId)
{
const Token * varTok = openParenthesisToken->tokAt(-3);
return Token::Match(varTok, "%varid% . %name% (", varId) &&
varTok->next()->originalName() == emptyString;
}
static const Token * findOpenParentesisOfMove(const Token * moveVarTok)
{
const Token * tok = moveVarTok;
while (tok && tok->str() != "(")
tok = tok->previous();
return tok;
}
static const Token * findEndOfFunctionCallForParameter(const Token * parameterToken)
{
if (!parameterToken)
return nullptr;
const Token * parent = parameterToken->astParent();
while (parent && !parent->isOp() && parent->str() != "(")
parent = parent->astParent();
if (!parent)
return nullptr;
return nextAfterAstRightmostLeaf(parent);
}
static void valueFlowAfterMove(TokenList* tokenlist, SymbolDatabase* symboldatabase, const Settings* settings)
{
if (!tokenlist->isCPP() || settings->standards.cpp < Standards::CPP11)
return;
for (const Scope * scope : symboldatabase->functionScopes) {
if (!scope)
continue;
const Token * start = scope->bodyStart;
if (scope->function) {
const Token * memberInitializationTok = scope->function->constructorMemberInitialization();
if (memberInitializationTok)
start = memberInitializationTok;
}
for (Token* tok = const_cast<Token*>(start); tok != scope->bodyEnd; tok = tok->next()) {
Token * varTok;
if (Token::Match(tok, "%var% . reset|clear (") && tok->next()->originalName() == emptyString) {
varTok = tok;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::MOVED;
value.moveKind = ValueFlow::Value::MoveKind::NonMovedVariable;
value.errorPath.emplace_back(tok, "Calling " + tok->next()->expressionString() + " makes " + tok->str() + " 'non-moved'");
value.setKnown();
std::list<ValueFlow::Value> values;
values.push_back(value);
const Variable *var = varTok->variable();
if (!var || (!var->isLocal() && !var->isArgument()))
continue;
const Token * const endOfVarScope = var->scope()->bodyEnd;
setTokenValue(varTok, value, settings);
valueFlowForward(varTok->next(), endOfVarScope, varTok, values, 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 Variable *var = varTok->variable();
if (!var)
continue;
const Token * const endOfVarScope = var->scope()->bodyEnd;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::MOVED;
value.moveKind = moveKind;
if (moveKind == ValueFlow::Value::MoveKind::MovedVariable)
value.errorPath.emplace_back(tok, "Calling std::move(" + varTok->str() + ")");
else // if (moveKind == ValueFlow::Value::ForwardedVariable)
value.errorPath.emplace_back(tok, "Calling std::forward(" + varTok->str() + ")");
value.setKnown();
std::list<ValueFlow::Value> values;
values.push_back(value);
const Token * openParentesisOfMove = findOpenParentesisOfMove(varTok);
const Token * endOfFunctionCall = findEndOfFunctionCallForParameter(openParentesisOfMove);
if (endOfFunctionCall)
valueFlowForward(
const_cast<Token*>(endOfFunctionCall), endOfVarScope, varTok, values, 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)
{
ValueFlow::Value v(val);
v.setKnown();
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");
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.begin(), args.end(), 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 void valueFlowConditionExpressions(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope * scope : symboldatabase->functionScopes) {
if (const Token* incompleteTok = findIncompleteVar(scope->bodyStart, scope->bodyEnd)) {
if (incompleteTok->isIncompleteVar()) {
if (settings->debugwarnings)
bailoutIncompleteVar(tokenlist, errorLogger, incompleteTok, "Skipping function due to incomplete variable " + incompleteTok->str());
break;
}
}
for (const Token* tok = 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, true, 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) {
ExpressionAnalyzer a1(condTok2, makeConditionValue(1, condTok2, true), tokenlist);
valueFlowGenericForward(startTok, startTok->link(), a1, settings);
}
OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(0, condTok2, true), tokenlist);
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) {
ExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist);
valueFlowGenericForward(startTok, startTok->link(), a1, settings);
if (is1) {
OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist);
valueFlowGenericForward(startTok, startTok->link(), a2, settings);
}
}
}
// Check if the block terminates early
if (isEscapeScope(blockTok, tokenlist)) {
for (const Token* condTok2:conds) {
ExpressionAnalyzer a1(condTok2, makeConditionValue(0, condTok2, false), tokenlist);
valueFlowGenericForward(startTok->link()->next(), scope->bodyEnd, a1, settings);
if (is1) {
OppositeExpressionAnalyzer a2(true, condTok2, makeConditionValue(1, condTok2, false), tokenlist);
valueFlowGenericForward(startTok->link()->next(), scope->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())) {
size_t srcSize = ValueFlow::getSizeOf(*src, settings);
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(TokenList* tokenlist, SymbolDatabase* symboldatabase)
{
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(), tokenlist->getSettings()->library, true, tokenlist->isCPP()))
continue;
if (tok->astOperand1()->valueType() && tok->astOperand2()->valueType()) {
if (isTruncated(
tok->astOperand2()->valueType(), tok->astOperand1()->valueType(), tokenlist->getSettings()))
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.begin(), vars.end(), [&](const Variable* var) {
if (rhsVarIds.count(var->declarationId()) > 0)
return true;
if (var->isLocal())
return var->isStatic();
return !var->isArgument();
}))
continue;
Token* start = nextAfterAstRightmostLeaf(tok);
const Token* end = scope->bodyEnd;
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, tokenlist->getSettings());
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, tokenlist->getSettings());
}
}
}
static void valueFlowSymbolicIdentity(TokenList* tokenlist)
{
for (Token* tok = tokenlist->front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
if (!Token::Match(tok, "*|/|<<|>>|^|+|-|%or%"))
continue;
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().begin(), vartok->values().end(), 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 (const ValueFlow::Value& v : values)
setTokenValue(tok, v, tokenlist->getSettings());
}
}
static void valueFlowSymbolicAbs(TokenList* tokenlist, SymbolDatabase* symboldatabase)
{
for (const Scope* scope : symboldatabase->functionScopes) {
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "abs|labs|llabs|fabs|fabsf|fabsl ("))
continue;
if (tok->hasKnownIntValue())
continue;
const Token* arg = tok->next()->astOperand2();
if (!arg)
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(), v, tokenlist->getSettings());
}
}
}
struct SymbolicInferModel : InferModel {
const Token* expr;
explicit SymbolicInferModel(const Token* tok) : expr(tok) {
assert(expr->exprId() != 0);
}
virtual bool match(const ValueFlow::Value& value) const override
{
return value.isSymbolicValue() && value.tokvalue && value.tokvalue->exprId() == expr->exprId();
}
virtual 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(TokenList* tokenlist, SymbolDatabase* symboldatabase)
{
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 (const ValueFlow::Value& value : values) {
setTokenValue(tok, value, tokenlist->getSettings());
}
}
}
}
static void valueFlowForwardConst(Token* start,
const Token* end,
const Variable* var,
const std::list<ValueFlow::Value>& values,
const Settings* const settings)
{
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
std::vector<ReferenceToken> refs = followAllReferences(tok);
ValueFlow::Value::ValueKind refKind =
refs.size() == 1 ? ValueFlow::Value::ValueKind::Known : ValueFlow::Value::ValueKind::Inconclusive;
for (const ReferenceToken& ref : refs) {
if (ref.token->varId() == var->declarationId()) {
for (ValueFlow::Value value : values) {
value.valueKind = refKind;
value.errorPath.insert(value.errorPath.end(), ref.errors.begin(), ref.errors.end());
setTokenValue(tok, value, settings);
}
return;
}
}
// Follow symbolic vaues
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.intvalue != 0) {
if (!value.isIntValue())
continue;
value.intvalue += v.intvalue;
}
value.valueKind = v.valueKind;
value.bound = v.bound;
value.errorPath.insert(value.errorPath.end(), v.errorPath.begin(), v.errorPath.end());
setTokenValue(tok, value, settings);
}
}
}();
}
}
}
static void valueFlowForwardAssign(Token* const tok,
const Token* expr,
std::vector<const Variable*> vars,
std::list<ValueFlow::Value> values,
const bool init,
TokenList* const tokenlist,
ErrorLogger* const errorLogger,
const Settings* const settings)
{
if (Token::simpleMatch(tok->astParent(), "return"))
return;
const Token* endOfVarScope = getEndOfExprScope(expr);
if (std::any_of(values.begin(), values.end(), std::mem_fn(&ValueFlow::Value::isLifetimeValue))) {
valueFlowForwardLifetime(tok, tokenlist, errorLogger, settings);
values.remove_if(std::mem_fn(&ValueFlow::Value::isLifetimeValue));
}
if (std::all_of(
vars.begin(), vars.end(), [&](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 ";
}
const std::string info = "Assignment '" + tok->astParent()->expressionString() + "', assigned value is " + valueKind + value.infoString();
value.errorPath.emplace_back(tok, 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.begin(), vars.end(), [&](const Variable* var) {
return var->isVolatile();
}))
lowerToPossible(values);
// Skip RHS
const Token * nextExpression = tok->astParent() ? nextAfterAstRightmostLeaf(tok->astParent()) : tok->next();
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(const_cast<Token*>(nextExpression), endOfVarScope, expr->variable(), constValues, settings);
}
valueFlowForward(const_cast<Token*>(nextExpression), endOfVarScope, expr, values, tokenlist, settings);
}
static void valueFlowForwardAssign(Token* const tok,
const Variable* const var,
const std::list<ValueFlow::Value>& values,
const bool,
const bool init,
TokenList* const 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()->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);
for (auto&& x : c1) {
if (c2.find(x) != c2.end())
return true;
}
return false;
}
static void valueFlowAfterAssign(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope * scope : symboldatabase->functionScopes) {
std::unordered_map<nonneg int, std::unordered_set<nonneg int>> backAssigns;
std::set<nonneg int> aliased;
for (Token* tok = const_cast<Token*>(scope->bodyStart); tok != scope->bodyEnd; tok = tok->next()) {
// Alias
if (tok->isUnaryOp("&")) {
aliased.insert(tok->astOperand1()->exprId());
continue;
}
// Assignment
if ((tok->str() != "=" && !isVariableInit(tok)) || (tok->astParent()))
continue;
// Lhs should be a variable
if (!tok->astOperand1() || !tok->astOperand1()->exprId())
continue;
const nonneg int exprid = tok->astOperand1()->exprId();
if (aliased.find(exprid) != aliased.end())
continue;
std::vector<const Variable*> vars = getLHSVariables(tok);
// Rhs values..
if (!tok->astOperand2() || tok->astOperand2()->values().empty())
continue;
std::list<ValueFlow::Value> values = truncateValues(
tok->astOperand2()->values(), tok->astOperand1()->valueType(), tok->astOperand2()->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;
});
// 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();
valueFlowForwardAssign(
tok->astOperand2(), 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,
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]);
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);
}
static ValueFlow::Value asImpossible(ValueFlow::Value v)
{
v.invertRange();
v.setImpossible();
return v;
}
static void insertImpossible(std::list<ValueFlow::Value>& values, const std::list<ValueFlow::Value>& input)
{
std::transform(input.begin(), input.end(), std::back_inserter(values), &asImpossible);
}
static void insertNegateKnown(std::list<ValueFlow::Value>& values, const std::list<ValueFlow::Value>& input)
{
for (ValueFlow::Value value:input) {
if (!value.isIntValue() && !value.isContainerSizeValue())
continue;
value.intvalue = !value.intvalue;
value.setKnown();
values.push_back(value);
}
}
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;
Condition() : vartok(nullptr), true_values(), false_values(), inverted(false), impossible(true) {}
};
virtual Analyzer::Result forward(Token* start,
const Token* stop,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const = 0;
virtual Analyzer::Result forward(Token* top,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const = 0;
virtual void reverse(Token* start,
const Token* endToken,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const = 0;
virtual std::vector<Condition> parse(const Token* tok, const Settings* settings) const = 0;
void traverseCondition(TokenList* tokenlist,
SymbolDatabase* symboldatabase,
const std::function<void(const Condition& cond, Token* tok, const Scope* scope)>& f) const
{
for (const Scope *scope : symboldatabase->functionScopes) {
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, tokenlist->getSettings())) {
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, tokenlist->getSettings()->library, true, tokenlist->isCPP()))
continue;
f(cond, tok, scope);
}
}
}
}
void beforeCondition(TokenList* tokenlist,
SymbolDatabase* symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings) const {
traverseCondition(tokenlist, symboldatabase, [&](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;
const 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.begin(), cond.false_values.end());
// 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() &&
isExpressionChanged(
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 (isExpressionChanged(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);
});
}
void afterCondition(TokenList* tokenlist,
SymbolDatabase* symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings) const {
traverseCondition(tokenlist, symboldatabase, [&](const Condition& cond, Token* tok, const Scope* scope) {
const Token* top = tok->astTop();
std::list<ValueFlow::Value> thenValues;
std::list<ValueFlow::Value> elseValues;
if (!Token::Match(tok, "!=|=|(|.") && tok != cond.vartok) {
thenValues.insert(thenValues.end(), cond.true_values.begin(), cond.true_values.end());
if (cond.impossible && isConditionKnown(tok, false))
insertImpossible(elseValues, cond.false_values);
}
if (!Token::Match(tok, "==|!")) {
elseValues.insert(elseValues.end(), cond.false_values.begin(), cond.false_values.end());
if (cond.impossible && isConditionKnown(tok, true)) {
insertImpossible(thenValues, cond.true_values);
if (tok == cond.vartok && astIsBool(tok))
insertNegateKnown(thenValues, cond.true_values);
}
}
if (cond.inverted)
std::swap(thenValues, elseValues);
if (Token::Match(tok->astParent(), "%oror%|&&")) {
Token* parent = tok->astParent();
if (astIsRHS(tok) && astIsLHS(parent) && parent->astParent() &&
parent->str() == parent->astParent()->str())
parent = parent->astParent();
else if (!astIsLHS(tok)) {
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());
}
const std::string& op(parent->str());
std::list<ValueFlow::Value> values;
if (op == "&&")
values = thenValues;
else if (op == "||")
values = elseValues;
if (Token::Match(tok, "==|!=") || (tok == cond.vartok && astIsBool(tok)))
changePossibleToKnown(values);
if (astIsFloat(cond.vartok, false) ||
(!cond.vartok->valueType() &&
std::all_of(values.begin(), values.end(), [](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)
return;
}
}
}
{
const Token* tok2 = tok;
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;
}
}
// if astParent is "!" we need to invert codeblock
{
const Token* tok2 = tok;
while (tok2 && tok2->astParent() && tok2->astParent()->str() != "?") {
const Token* parent = tok2->astParent();
while (parent && parent->str() == "&&")
parent = parent->astParent();
if (parent && (parent->str() == "!" || Token::simpleMatch(parent, "== false")))
std::swap(thenValues, elseValues);
tok2 = parent;
}
}
Token* condTop = tok;
while (Token::Match(condTop->astParent(), "%oror%|&&|!"))
condTop = condTop->astParent();
if (Token::simpleMatch(condTop->astParent(), "?")) {
Token* colon = condTop->astParent()->astOperand2();
forward(colon->astOperand1(), cond.vartok, thenValues, tokenlist, settings);
forward(colon->astOperand2(), cond.vartok, elseValues, tokenlist, settings);
// TODO: Handle after condition
return;
}
if (!Token::Match(top->previous(), "if|while|for ("))
return;
if (top->previous()->str() == "for") {
if (!Token::Match(tok, "%comp%"))
return;
if (!Token::simpleMatch(tok->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 = tok->astOperand1();
if (!childTok)
childTok = tok->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;
execute(initTok, &pm, nullptr, nullptr);
MathLib::bigint result = 1;
execute(tok, &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);
valueFlowSetConditionToKnown(tok, 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;
} else 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 (tok->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.begin(),
thenValues.end(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isPossible));
std::copy_if(elseValues.begin(),
elseValues.end(),
std::back_inserter(values),
std::mem_fn(&ValueFlow::Value::isPossible));
}
if (values.empty())
return;
if (dead_if || dead_else) {
const Token* parent = tok->astParent();
// Skip the not operator
while (Token::simpleMatch(parent, "!"))
parent = parent->astParent();
bool possible = false;
if (Token::Match(parent, "&&|%oror%")) {
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 {
valueFlowSetConditionToKnown(tok, values, true);
valueFlowSetConditionToKnown(tok, values, false);
}
}
if (values.empty())
return;
forward(after, getEndOfExprScope(cond.vartok, scope), cond.vartok, values, tokenlist, settings);
}
});
}
virtual ~ConditionHandler() {}
};
static void valueFlowCondition(const ValuePtr<ConditionHandler>& handler,
TokenList* tokenlist,
SymbolDatabase* symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings)
{
handler->beforeCondition(tokenlist, symboldatabase, errorLogger, settings);
handler->afterCondition(tokenlist, symboldatabase, errorLogger, settings);
}
struct SimpleConditionHandler : ConditionHandler {
virtual Analyzer::Result forward(Token* start,
const Token* stop,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const override {
return valueFlowForward(start->next(), stop, exprTok, values, tokenlist, settings);
}
virtual Analyzer::Result forward(Token* top,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const override {
return valueFlowForward(top, exprTok, values, tokenlist, settings);
}
virtual void reverse(Token* start,
const Token* endToken,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const override {
return valueFlowReverse(start, endToken, exprTok, values, tokenlist, settings);
}
virtual std::vector<Condition> parse(const Token* tok, const Settings*) const override {
Condition cond;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
const Token *vartok = parseCompareInt(tok, true_value, false_value);
if (vartok) {
if (vartok->hasKnownIntValue())
return {};
if (vartok->str() == "=" && vartok->astOperand1() && vartok->astOperand2())
vartok = vartok->astOperand1();
cond.true_values.push_back(true_value);
cond.false_values.push_back(false_value);
cond.vartok = vartok;
return {cond};
}
if (tok->str() == "!") {
vartok = tok->astOperand1();
} else if (tok->astParent() && (Token::Match(tok->astParent(), "%oror%|&&|?") ||
Token::Match(tok->astParent()->previous(), "if|while ("))) {
if (Token::simpleMatch(tok, "="))
vartok = tok->astOperand1();
else if (!Token::Match(tok, "%comp%|%assign%"))
vartok = tok;
}
if (!vartok)
return {};
cond.true_values.emplace_back(tok, 0LL);
cond.false_values.emplace_back(tok, 0LL);
cond.vartok = vartok;
return {cond};
}
};
struct IntegralInferModel : InferModel {
virtual bool match(const ValueFlow::Value& value) const override {
return value.isIntValue();
}
virtual ValueFlow::Value yield(MathLib::bigint value) const override
{
ValueFlow::Value result(value);
result.valueType = ValueFlow::Value::ValueType::INT;
result.setKnown();
return result;
}
};
ValuePtr<InferModel> makeIntegralInferModel() {
return IntegralInferModel{};
}
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{};
}
ValueFlow::Value inferCondition(std::string op, MathLib::bigint val, const Token* varTok)
{
if (!varTok)
return ValueFlow::Value{};
if (varTok->hasKnownIntValue())
return ValueFlow::Value{};
std::vector<ValueFlow::Value> r = infer(IntegralInferModel{}, op, val, varTok->values());
if (r.size() == 1 && r.front().isKnown())
return r.front();
return ValueFlow::Value{};
}
struct IteratorInferModel : InferModel {
virtual ValueFlow::Value::ValueType getType() const = 0;
virtual bool match(const ValueFlow::Value& value) const override {
return value.valueType == getType();
}
virtual ValueFlow::Value yield(MathLib::bigint value) const override
{
ValueFlow::Value result(value);
result.valueType = getType();
result.setKnown();
return result;
}
};
struct EndIteratorInferModel : IteratorInferModel {
virtual ValueFlow::Value::ValueType getType() const override {
return ValueFlow::Value::ValueType::ITERATOR_END;
}
};
struct StartIteratorInferModel : IteratorInferModel {
virtual ValueFlow::Value::ValueType getType() const override {
return ValueFlow::Value::ValueType::ITERATOR_END;
}
};
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 (tok->variable() && (Token::Match(tok->astParent(), "?|&&|!|%oror%") ||
Token::Match(tok->astParent()->previous(), "if|while ("))) {
std::vector<ValueFlow::Value> result = infer(IntegralInferModel{}, "!=", tok->values(), 0);
if (result.size() != 1)
continue;
ValueFlow::Value value = result.front();
value.intvalue = 1;
value.bound = ValueFlow::Value::Bound::Point;
setTokenValue(tok, value, settings);
} else 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, value, settings);
}
}
} else {
std::vector<ValueFlow::Value> result =
infer(IntegralInferModel{}, tok->str(), tok->astOperand1()->values(), tok->astOperand2()->values());
for (const ValueFlow::Value& value : result) {
setTokenValue(tok, value, settings);
}
}
}
}
}
struct SymbolicConditionHandler : SimpleConditionHandler {
virtual std::vector<Condition> parse(const Token* tok, const 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 {};
std::vector<Condition> result;
for (int i = 0; i < 2; i++) {
const bool lhs = i == 0;
const Token* vartok = lhs ? tok->astOperand1() : tok->astOperand2();
const Token* valuetok = lhs ? tok->astOperand2() : tok->astOperand1();
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 = {true_value};
cond.false_values = {false_value};
cond.vartok = vartok;
result.push_back(cond);
}
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,
TokenList* tokenlist,
ErrorLogger* errorLogger,
const Settings* settings)
{
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, 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..
const Token *parent = tok2;
while (parent && parent->str() == tok2->str())
parent = parent->astParent();
// Jump to end of condition
if (parent && parent->str() == "(") {
tok2 = parent->link();
// cast
if (Token::simpleMatch(tok2, ") ("))
tok2 = tok2->linkAt(1);
}
}
}
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;
else if (Token::simpleMatch(tok2, ") {") && 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 (Token::simpleMatch(tok2, ") {")) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "For loop skipping {} code");
tok2 = tok2->linkAt(1);
if (Token::simpleMatch(tok2, "} else {"))
tok2 = tok2->linkAt(2);
}
}
}
static void valueFlowForLoopSimplifyAfter(Token* fortok,
nonneg int varid,
const MathLib::bigint num,
TokenList* tokenlist,
const Settings* settings)
{
const Token *vartok = nullptr;
for (const Token *tok = fortok; tok; tok = tok->next()) {
if (tok->varId() == varid) {
vartok = tok;
break;
}
}
if (!vartok || !vartok->variable())
return;
const Variable *var = vartok->variable();
const Token *endToken = nullptr;
if (var->isLocal())
endToken = var->scope()->bodyEnd;
else
endToken = fortok->scope()->bodyEnd;
Token* blockTok = fortok->linkAt(1)->linkAt(1);
std::list<ValueFlow::Value> values;
values.emplace_back(num);
values.back().errorPath.emplace_back(fortok,"After for loop, " + var->name() + " has value " + values.back().infoString());
if (blockTok != endToken) {
valueFlowForward(blockTok->next(), endToken, vartok, values, tokenlist, settings);
}
}
static void valueFlowForLoop(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope &scope : symboldatabase->scopeList) {
if (scope.type != Scope::eFor)
continue;
Token* tok = const_cast<Token*>(scope.classDef);
Token* const bodyStart = const_cast<Token*>(scope.bodyStart);
if (!Token::simpleMatch(tok->next()->astOperand2(), ";") ||
!Token::simpleMatch(tok->next()->astOperand2()->astOperand2(), ";"))
continue;
nonneg int varid;
bool knownInitValue, partialCond;
MathLib::bigint initValue, stepValue, lastValue;
if (extractForLoopValues(tok, &varid, &knownInitValue, &initValue, &partialCond, &stepValue, &lastValue)) {
const bool executeBody = !knownInitValue || initValue <= lastValue;
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(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(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)) {
ProgramMemory::Map::const_iterator it;
for (it = mem1.begin(); it != mem1.end(); ++it) {
if (!it->second.isIntValue())
continue;
valueFlowForLoopSimplify(
bodyStart, it->first.tok, false, it->second.intvalue, tokenlist, errorLogger, settings);
}
for (it = mem2.begin(); it != mem2.end(); ++it) {
if (!it->second.isIntValue())
continue;
valueFlowForLoopSimplify(
bodyStart, it->first.tok, false, it->second.intvalue, tokenlist, errorLogger, settings);
}
for (it = memAfter.begin(); it != memAfter.end(); ++it) {
if (!it->second.isIntValue())
continue;
valueFlowForLoopSimplifyAfter(
tok, it->first.getExpressionId(), it->second.intvalue, tokenlist, settings);
}
}
}
}
}
struct MultiValueFlowAnalyzer : ValueFlowAnalyzer {
std::unordered_map<nonneg int, ValueFlow::Value> values;
std::unordered_map<nonneg int, const Variable*> vars;
SymbolDatabase* symboldatabase;
MultiValueFlowAnalyzer() : ValueFlowAnalyzer(), values(), vars(), symboldatabase(nullptr) {}
MultiValueFlowAnalyzer(const std::unordered_map<const Variable*, ValueFlow::Value>& args, const TokenList* t, SymbolDatabase* s)
: ValueFlowAnalyzer(t), values(), vars(), symboldatabase(s) {
for (const auto& p:args) {
values[p.first->declarationId()] = p.second;
vars[p.first->declarationId()] = p.first;
}
}
virtual const std::unordered_map<nonneg int, const Variable*>& getVars() const {
return vars;
}
virtual const ValueFlow::Value* getValue(const Token* tok) const override {
if (tok->varId() == 0)
return nullptr;
auto it = values.find(tok->varId());
if (it == values.end())
return nullptr;
return &it->second;
}
virtual ValueFlow::Value* getValue(const Token* tok) override {
if (tok->varId() == 0)
return nullptr;
auto it = values.find(tok->varId());
if (it == values.end())
return nullptr;
return &it->second;
}
virtual void makeConditional() override {
for (auto&& p:values) {
p.second.conditional = true;
}
}
virtual void addErrorPath(const Token* tok, const std::string& s) override {
for (auto&& p:values) {
p.second.errorPath.emplace_back(tok, "Assuming condition is " + s);
}
}
virtual bool isAlias(const Token* tok, bool& inconclusive) const override {
const auto range = SelectValueFromVarIdMapRange(&values);
for (const auto& p:getVars()) {
nonneg int varid = p.first;
const Variable* var = p.second;
if (tok->varId() == varid)
return true;
if (isAliasOf(var, tok, varid, range, &inconclusive))
return true;
}
return false;
}
virtual bool isGlobal() const override {
return false;
}
virtual bool lowerToPossible() override {
for (auto&& p:values) {
if (p.second.isImpossible())
return false;
p.second.changeKnownToPossible();
}
return true;
}
virtual bool lowerToInconclusive() override {
for (auto&& p:values) {
if (p.second.isImpossible())
return false;
p.second.setInconclusive();
}
return true;
}
virtual bool isConditional() const override {
for (auto&& p:values) {
if (p.second.conditional)
return true;
if (p.second.condition)
return !p.second.isImpossible();
}
return false;
}
virtual bool stopOnCondition(const Token*) const override {
return isConditional();
}
virtual bool updateScope(const Token* endBlock, bool) const override {
const Scope* scope = endBlock->scope();
if (!scope)
return false;
if (scope->type == Scope::eLambda) {
for (const auto& p:values) {
if (!p.second.isLifetimeValue())
return false;
}
return true;
} else if (scope->type == Scope::eIf || scope->type == Scope::eElse || scope->type == Scope::eWhile ||
scope->type == Scope::eFor) {
auto pred = [](const ValueFlow::Value& value) {
if (value.isKnown())
return true;
if (value.isImpossible())
return true;
if (value.isLifetimeValue())
return true;
return false;
};
if (std::all_of(values.begin(), values.end(), std::bind(pred, std::bind(SelectMapValues{}, std::placeholders::_1))))
return true;
if (isConditional())
return false;
const Token* condTok = getCondTokFromEnd(endBlock);
std::set<nonneg int> varids;
std::transform(getVars().begin(), getVars().end(), std::inserter(varids, varids.begin()), SelectMapKeys{});
return bifurcate(condTok, varids, getSettings());
}
return false;
}
virtual bool match(const Token* tok) const override {
return values.count(tok->varId()) > 0;
}
virtual ProgramState getProgramState() const override {
ProgramState ps;
for (const auto& p : values) {
const Variable* var = vars.at(p.first);
if (!var)
continue;
ps[var->nameToken()] = p.second;
}
return ps;
}
virtual void forkScope(const Token* endBlock) override {
ProgramMemory pm{getProgramState()};
const Scope* scope = endBlock->scope();
const Token* condTok = getCondTokFromEnd(endBlock);
if (scope && condTok)
programMemoryParseCondition(pm, condTok, nullptr, getSettings(), scope->type != Scope::eElse);
if (condTok && Token::simpleMatch(condTok->astParent(), ";")) {
ProgramMemory endMemory;
if (valueFlowForLoop2(condTok->astTop()->previous(), nullptr, &endMemory, nullptr))
pm.replace(endMemory);
}
// ProgramMemory pm = pms.get(endBlock->link()->next(), getProgramState());
for (const auto& p : pm) {
nonneg int varid = p.first.getExpressionId();
if (symboldatabase && !symboldatabase->isVarId(varid))
continue;
ValueFlow::Value value = p.second;
if (vars.count(varid) != 0)
continue;
if (value.isImpossible())
continue;
value.setPossible();
values[varid] = value;
if (symboldatabase)
vars[varid] = symboldatabase->getVariableFromVarId(varid);
}
}
};
template<class Key, class F>
bool productParams(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();
}
for (const auto& p:vars) {
if (args.size() > 256)
return false;
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.second.path == 0)
continue;
if (q.second.path != value.path)
return;
}
}
arg[p.first] = value;
new_args.push_back(arg);
}
std::copy(new_args.begin(), new_args.end(), std::back_inserter(args));
});
}
for (const auto& arg:args) {
if (arg.empty())
continue;
bool skip = false;
// Make sure all arguments are the same path
MathLib::bigint path = arg.begin()->second.path;
for (const auto& p:arg) {
if (p.second.path != path) {
skip = true;
break;
}
}
if (skip)
continue;
f(arg);
}
return true;
}
static void valueFlowInjectParameter(TokenList* tokenlist,
SymbolDatabase* symboldatabase,
ErrorLogger* errorLogger,
const Settings* settings,
const Scope* functionScope,
const std::unordered_map<const Variable*, std::list<ValueFlow::Value>>& vars)
{
bool r = productParams(vars, [&](const std::unordered_map<const Variable*, ValueFlow::Value>& arg) {
MultiValueFlowAnalyzer a(arg, tokenlist, symboldatabase);
valueFlowGenericForward(const_cast<Token*>(functionScope->bodyStart), functionScope->bodyEnd, a, settings);
});
if (!r) {
std::string fname = "<unknown>";
Function* f = functionScope->function;
if (f)
fname = f->name();
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, functionScope->bodyStart, "Too many argument passed to " + fname);
}
}
static void valueFlowInjectParameter(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(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope &scope : symboldatabase->scopeList) {
if (scope.type != Scope::ScopeType::eSwitch)
continue;
if (!Token::Match(scope.classDef, "switch ( %var% ) {"))
continue;
const Token *vartok = scope.classDef->tokAt(2);
const Variable *var = vartok->variable();
if (!var)
continue;
// bailout: global non-const variables
if (!(var->isLocal() || var->isArgument()) && !var->isConst()) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, vartok, "switch variable " + var->name() + " is global");
continue;
}
for (Token *tok = scope.bodyStart->next(); tok != scope.bodyEnd; tok = tok->next()) {
if (tok->str() == "{") {
tok = tok->link();
continue;
}
if (Token::Match(tok, "case %num% :")) {
std::list<ValueFlow::Value> values;
values.emplace_back(MathLib::toLongNumber(tok->next()->str()));
values.back().condition = tok;
const std::string info("case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here.");
values.back().errorPath.emplace_back(tok, info);
bool known = false;
if ((Token::simpleMatch(tok->previous(), "{") || Token::simpleMatch(tok->tokAt(-2), "break ;")) && !Token::Match(tok->tokAt(3), ";| case"))
known = true;
while (Token::Match(tok->tokAt(3), ";| case %num% :")) {
known = false;
tok = tok->tokAt(3);
if (!tok->isName())
tok = tok->next();
values.emplace_back(MathLib::toLongNumber(tok->next()->str()));
values.back().condition = tok;
const std::string info2("case " + tok->next()->str() + ": " + vartok->str() + " is " + tok->next()->str() + " here.");
values.back().errorPath.emplace_back(tok, info2);
}
for (std::list<ValueFlow::Value>::const_iterator val = values.begin(); val != values.end(); ++val) {
valueFlowReverse(tokenlist,
const_cast<Token*>(scope.classDef),
vartok,
*val,
ValueFlow::Value(),
errorLogger,
settings);
}
if (vartok->variable()->scope()) {
if (known)
values.back().setKnown();
// FIXME We must check if there is a return. See #9276
/*
valueFlowForwardVariable(tok->tokAt(3),
vartok->variable()->scope()->bodyEnd,
vartok->variable(),
vartok->varId(),
values,
values.back().isKnown(),
false,
tokenlist,
errorLogger,
settings);
*/
}
}
}
}
}
static 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;
TokenList tokenList(settings);
{
const std::string code = "return " + returnValue + ";";
std::istringstream istr(code);
if (!tokenList.createTokens(istr))
return;
}
// combine operators, set links, etc..
std::stack<Token *> lpar;
for (Token *tok2 = tokenList.front(); tok2; tok2 = tok2->next()) {
if (Token::Match(tok2, "[!<>=] =")) {
tok2->str(tok2->str() + "=");
tok2->deleteNext();
} else if (tok2->str() == "(")
lpar.push(tok2);
else if (tok2->str() == ")") {
if (lpar.empty())
return;
Token::createMutualLinks(lpar.top(), tok2);
lpar.pop();
}
}
if (!lpar.empty())
return;
// set varids
std::unordered_map<nonneg int, const Token*> lookupVarId;
for (Token* tok2 = tokenList.front(); tok2; tok2 = tok2->next()) {
if (tok2->str().compare(0, 3, "arg") != 0)
continue;
nonneg int id = std::atoi(tok2->str().c_str() + 3);
tok2->varId(id);
lookupVarId[id] = tok2;
}
// Evaluate expression
tokenList.createAst();
Token* expr = tokenList.front()->astOperand1();
ValueFlow::valueFlowConstantFoldAST(expr, settings);
productParams(argValues, [&](const std::unordered_map<nonneg int, ValueFlow::Value>& arg) {
ProgramMemory pm{};
for (const auto& p : arg) {
const Token* varTok = lookupVarId[p.first];
pm.setValue(varTok, p.second);
}
MathLib::bigint result = 0;
bool error = false;
execute(expr, &pm, &result, &error);
if (error)
return;
ValueFlow::Value value(result);
value.setKnown();
for (auto&& p : arg) {
if (p.second.isPossible())
value.setPossible();
if (p.second.isInconclusive()) {
value.setInconclusive();
break;
}
}
setTokenValue(tok, value, settings);
});
}
template<class Iterator>
struct IteratorRange
{
Iterator mBegin;
Iterator mEnd;
Iterator begin() const {
return mBegin;
}
Iterator end() const {
return mEnd;
}
};
template<class Iterator>
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.rbegin(), symboldatabase->functionScopes.rend())) {
const Function* function = scope->function;
if (!function)
continue;
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "%name% ("))
continue;
const Function * const calledFunction = tok->function();
if (!calledFunction) {
// library function?
const std::string& returnValue(settings->library.returnValue(tok));
if (!returnValue.empty())
valueFlowLibraryFunction(tok->next(), returnValue, settings);
continue;
}
const Scope * const calledFunctionScope = calledFunction->functionScope;
if (!calledFunctionScope)
continue;
id++;
std::unordered_map<const Variable*, std::list<ValueFlow::Value>> argvars;
// TODO: Rewrite this. It does not work well to inject 1 argument at a time.
const std::vector<const Token *> &callArguments = getArguments(tok);
for (int argnr = 0U; argnr < callArguments.size(); ++argnr) {
const Token *argtok = callArguments[argnr];
// Get function argument
const Variable * const argvar = calledFunction->getArgumentVar(argnr);
if (!argvar)
break;
// passing value(s) to function
std::list<ValueFlow::Value> argvalues(getFunctionArgumentValues(argtok));
// 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(tokenlist->isCPP(), 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 = MathLib::toString(argnr + 1) + getOrdinalText(argnr + 1);
v.errorPath.emplace_back(argtok,
"Calling function '" +
calledFunction->name() +
"', " +
nr +
" argument '" +
argtok->expressionString() +
"' value is " +
v.infoString());
v.path = 256 * v.path + id % 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, symboldatabase, errorLogger, settings, calledFunctionScope, argvars);
}
}
}
static void valueFlowFunctionDefaultParameter(TokenList* tokenlist, 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(v);
}
if (!argvalues.empty())
valueFlowInjectParameter(tokenlist, settings, var, scope, argvalues);
}
}
}
}
static bool isKnown(const Token * tok)
{
return tok && tok->hasKnownIntValue();
}
static void valueFlowFunctionReturn(TokenList *tokenlist, ErrorLogger *errorLogger)
{
for (Token *tok = tokenlist->back(); tok; tok = tok->previous()) {
if (tok->str() != "(" || !tok->astOperand1() || !tok->astOperand1()->function())
continue;
if (tok->hasKnownValue())
continue;
// Arguments..
std::vector<MathLib::bigint> parvalues;
if (tok->astOperand2()) {
const Token *partok = tok->astOperand2();
while (partok && partok->str() == "," && isKnown(partok->astOperand2()))
partok = partok->astOperand1();
if (!isKnown(partok))
continue;
parvalues.push_back(partok->values().front().intvalue);
partok = partok->astParent();
while (partok && partok->str() == ",") {
parvalues.push_back(partok->astOperand2()->values().front().intvalue);
partok = partok->astParent();
}
if (partok != tok)
continue;
}
// Get scope and args of function
const Function * const function = tok->astOperand1()->function();
const Scope * const functionScope = function->functionScope;
if (!functionScope || !Token::simpleMatch(functionScope->bodyStart, "{ return")) {
if (functionScope && tokenlist->getSettings()->debugwarnings && Token::findsimplematch(functionScope->bodyStart, "return", functionScope->bodyEnd))
bailout(tokenlist, errorLogger, tok, "function return; nontrivial function body");
continue;
}
ProgramMemory programMemory;
for (std::size_t i = 0; i < parvalues.size(); ++i) {
const Variable * const arg = function->getArgumentVar(i);
if (!arg || !Token::Match(arg->typeStartToken(), "%type% %name% ,|)")) {
if (tokenlist->getSettings()->debugwarnings)
bailout(tokenlist, errorLogger, tok, "function return; unhandled argument type");
programMemory.clear();
break;
}
programMemory.setIntValue(arg->nameToken(), parvalues[i]);
}
if (programMemory.empty() && !parvalues.empty())
continue;
// Determine return value of subfunction..
MathLib::bigint result = 0;
bool error = false;
execute(functionScope->bodyStart->next()->astOperand1(),
&programMemory,
&result,
&error);
if (!error) {
ValueFlow::Value v(result);
if (function->hasVirtualSpecifier())
v.setPossible();
else
v.setKnown();
setTokenValue(tok, v, tokenlist->getSettings());
}
}
}
static bool needsInitialization(const Variable* var, bool cpp)
{
if (!var)
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() && var->valueType()->isPrimitive())
return true;
return false;
}
static void addToErrorPath(ValueFlow::Value& value, const ValueFlow::Value& from)
{
std::unordered_set<const Token*> locations;
std::transform(value.errorPath.begin(),
value.errorPath.end(),
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.begin(),
from.errorPath.end(),
std::back_inserter(value.errorPath),
[&](const ErrorPathItem& e) {
return locations.insert(e.first).second;
});
}
static void valueFlowUninit(TokenList* tokenlist, SymbolDatabase* /*symbolDatabase*/, const Settings* settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!Token::Match(tok,"[;{}] %type%"))
continue;
if (!tok->scope()->isExecutable())
continue;
const Token *vardecl = tok->next();
bool stdtype = false;
bool pointer = false;
while (Token::Match(vardecl, "%name%|::|*") && vardecl->varId() == 0) {
stdtype |= vardecl->isStandardType();
pointer |= vardecl->str() == "*";
vardecl = vardecl->next();
}
// if (!stdtype && !pointer)
// continue;
if (!Token::Match(vardecl, "%var% ;"))
continue;
const Variable *var = vardecl->variable();
if (!needsInitialization(var, tokenlist->isCPP()))
continue;
if (var->nameToken() != vardecl || var->isInit())
continue;
if (!var->isLocal() || var->isStatic() || var->isExtern() || var->isReference() || var->isThrow())
continue;
if (!var->type() && !stdtype && !pointer)
continue;
ValueFlow::Value uninitValue;
uninitValue.setKnown();
uninitValue.valueType = ValueFlow::Value::ValueType::UNINIT;
uninitValue.tokvalue = vardecl;
bool partial = false;
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(), vardecl, uninitValue, tokenlist);
valueFlowGenericForward(vardecl->next(), vardecl->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;
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;
const ValueFlow::Value& v = p.second;
setTokenValue(tok2, v, settings);
}
if (partial)
continue;
valueFlowForward(vardecl->next(), vardecl->scope()->bodyEnd, var->nameToken(), {uninitValue}, tokenlist, settings);
}
}
static bool isContainerSizeChanged(nonneg int varId,
const Token* start,
const Token* end,
const Settings* settings = nullptr,
int depth = 20);
static bool isContainerSizeChangedByFunction(const Token* tok, 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% (")) {
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->hasVirtualSpecifier()) {
const Variable *arg = fun->getArgumentVar(narg);
if (arg) {
if (!arg->isReference() && !addressOf)
return false;
if (!addressOf && arg->isConst())
return false;
if (arg->valueType() && arg->valueType()->constness == 1)
return false;
const Scope * scope = fun->functionScope;
if (scope) {
// Argument not used
if (!arg->nameToken())
return false;
if (depth > 0)
return isContainerSizeChanged(
arg->declarationId(), scope->bodyStart, scope->bodyEnd, settings, depth - 1);
}
// Don't know => Safe guess
return true;
}
}
bool inconclusive = false;
const bool isChanged = isVariableChangedByFunctionCall(tok, 0, settings, &inconclusive);
return (isChanged || inconclusive);
}
struct ContainerExpressionAnalyzer : ExpressionAnalyzer {
ContainerExpressionAnalyzer() : ExpressionAnalyzer() {}
ContainerExpressionAnalyzer(const Token* expr, const ValueFlow::Value& val, const TokenList* t)
: ExpressionAnalyzer(expr, val, t)
{}
virtual bool match(const Token* tok) const override {
return tok->exprId() == expr->exprId() || (astIsIterator(tok) && isAliasOf(tok, expr->exprId()));
}
virtual Action isWritable(const Token* tok, Direction d) const override {
if (astIsIterator(tok))
return Action::None;
if (d == Direction::Reverse)
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().begin(), rhs->values().end(), [&](const ValueFlow::Value &rhsval) {
return rhsval.isKnown() && rhsval.isContainerSizeValue();
}))
return Action::Read | Action::Write | Action::Incremental;
}
} else if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Action action = container->getAction(tok->strAt(2));
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;
}
virtual void writeValue(ValueFlow::Value* val, const Token* tok, Direction d) const override {
if (d == Direction::Reverse)
return;
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);
if (container->stdStringLike && Token::simpleMatch(parent, "+=") && parent->astOperand2()) {
const Token* rhs = parent->astOperand2();
const Library::Container* rhsContainer = getLibraryContainer(rhs);
if (rhs->tokType() == Token::eString)
val->intvalue += Token::getStrLength(rhs);
else if (rhsContainer && rhsContainer->stdStringLike) {
for (const ValueFlow::Value &rhsval : rhs->values()) {
if (rhsval.isKnown() && rhsval.isContainerSizeValue()) {
val->intvalue += rhsval.intvalue;
}
}
}
} else if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Action action = container->getAction(tok->strAt(2));
if (action == Library::Container::Action::PUSH)
val->intvalue++;
if (action == Library::Container::Action::POP)
val->intvalue--;
}
}
virtual 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) && isContainerSizeChanged(tok, getSettings()))
return Action::Invalid;
return read;
}
};
static Analyzer::Result valueFlowContainerForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
const ValueFlow::Value& value,
TokenList* tokenlist)
{
ContainerExpressionAnalyzer a(exprTok, value, tokenlist);
return valueFlowGenericForward(startToken, endToken, a, tokenlist->getSettings());
}
static Analyzer::Result valueFlowContainerForwardRecursive(Token* top,
const Token* exprTok,
const ValueFlow::Value& value,
TokenList* tokenlist)
{
ContainerExpressionAnalyzer a(exprTok, value, tokenlist);
return valueFlowGenericForward(top, a, tokenlist->getSettings());
}
static Analyzer::Result valueFlowContainerForward(Token* startToken,
const Token* exprTok,
const ValueFlow::Value& value,
TokenList* tokenlist)
{
const Token* endToken = nullptr;
const Function* f = Scope::nestedInFunction(startToken->scope());
if (f && f->functionScope)
endToken = f->functionScope->bodyEnd;
return valueFlowContainerForward(startToken, endToken, exprTok, value, tokenlist);
}
static void valueFlowContainerReverse(Token* tok,
const Token* const endToken,
const Token* const varToken,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings)
{
for (const ValueFlow::Value& value : values) {
ContainerExpressionAnalyzer a(varToken, value, tokenlist);
valueFlowGenericReverse(tok, endToken, a, settings);
}
}
bool isContainerSizeChanged(const Token* tok, const Settings* settings, int depth)
{
if (!tok)
return false;
if (!tok->valueType() || !tok->valueType()->container)
return true;
if (Token::Match(tok, "%name% %assign%|<<"))
return true;
if (Token::Match(tok, "%var% [") && tok->valueType()->container->stdAssociativeLike)
return true;
if (Token::Match(tok, "%name% . %name% (")) {
Library::Container::Action action = tok->valueType()->container->getAction(tok->strAt(2));
Library::Container::Yield yield = tok->valueType()->container->getYield(tok->strAt(2));
switch (action) {
case Library::Container::Action::RESIZE:
case Library::Container::Action::CLEAR:
case Library::Container::Action::PUSH:
case Library::Container::Action::POP:
case Library::Container::Action::CHANGE:
case Library::Container::Action::INSERT:
case Library::Container::Action::ERASE:
return true;
case Library::Container::Action::NO_ACTION: // might be unknown action
return yield == Library::Container::Yield::NO_YIELD;
case Library::Container::Action::FIND:
case Library::Container::Action::CHANGE_CONTENT:
case Library::Container::Action::CHANGE_INTERNAL:
break;
}
}
if (isContainerSizeChangedByFunction(tok, settings, depth))
return true;
return false;
}
static bool isContainerSizeChanged(nonneg int varId,
const Token* start,
const Token* end,
const Settings* settings,
int depth)
{
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() != varId)
continue;
if (isContainerSizeChanged(tok, 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();
std::list<ValueFlow::Value> values = inTok->values();
const bool constValue = inTok->isNumber();
valueFlowForwardAssign(inTok, var, values, constValue, true, tokenlist, errorLogger, settings);
} else if (Token::Match(tok, "%var% ;")) {
std::list<ValueFlow::Value> values;
ValueFlow::Value v(0);
v.setKnown();
values.push_back(v);
valueFlowForwardAssign(tok, var, values, false, true, tokenlist, errorLogger, settings);
}
}
} else if (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, "( )")) {
std::list<ValueFlow::Value> values;
ValueFlow::Value v(0);
v.setKnown();
values.push_back(v);
valueFlowForwardAssign(ftok, tok, vars, values, false, tokenlist, errorLogger, settings);
} else {
tok->removeValues(std::mem_fn(&ValueFlow::Value::isIntValue));
Token* inTok = ftok->astOperand2();
if (!inTok)
continue;
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;
std::list<ValueFlow::Value> values;
ValueFlow::Value v(0);
v.setKnown();
values.push_back(v);
valueFlowForwardAssign(ftok, tok, vars, values, false, tokenlist, errorLogger, settings);
} else if (Token::simpleMatch(tok->astParent(), ". get ( )")) {
ValueFlow::Value v = makeSymbolic(tok);
setTokenValue(tok->astParent()->tokAt(2), 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 void valueFlowIterators(TokenList *tokenlist, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
if (!tok->scope())
continue;
if (!tok->scope()->isExecutable())
continue;
if (!astIsContainer(tok))
continue;
if (Token::Match(tok->astParent(), ". %name% (")) {
Library::Container::Yield yield = getLibraryContainer(tok)->getYield(tok->astParent()->strAt(1));
ValueFlow::Value v(0);
v.setKnown();
if (yield == Library::Container::Yield::START_ITERATOR) {
v.valueType = ValueFlow::Value::ValueType::ITERATOR_START;
setTokenValue(tok->astParent()->tokAt(2), v, settings);
} else if (yield == Library::Container::Yield::END_ITERATOR) {
v.valueType = ValueFlow::Value::ValueType::ITERATOR_END;
setTokenValue(tok->astParent()->tokAt(2), 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 {
virtual std::vector<Condition> parse(const Token* tok, const Settings*) const override {
Condition cond;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
if (Token::Match(tok, "==|!=")) {
if (!tok->astOperand1() || !tok->astOperand2())
return {};
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 {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, v, settings);
}
}
}
static std::vector<ValueFlow::Value> getContainerValues(const Token* tok)
{
std::vector<ValueFlow::Value> values;
if (tok) {
std::copy_if(tok->values().begin(),
tok->values().end(),
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> getInitListSize(const Token* tok,
const Library::Container* container,
bool known = true)
{
std::vector<const Token*> args = getArguments(tok);
if (!args.empty() && container->stdStringLike) {
if (astIsGenericChar(args[0])) // init list of chars
return { makeContainerSizeValue(args.size(), known) };
if (astIsIntegral(args[0], false)) { // { count, 'c' }
if (args.size() > 1)
return {makeContainerSizeValue(args[0], known)};
} else 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 {};
} else if ((args.size() == 1 && astIsContainer(args[0]) && args[0]->valueType()->container == container) ||
isIteratorPair(args)) {
return getContainerValues(args[0]);
}
return {makeContainerSizeValue(args.size(), known)};
}
static void valueFlowContainerSize(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger * /*errorLogger*/, const Settings *settings)
{
std::map<int, std::size_t> static_sizes;
// declaration
for (const Variable *var : symboldatabase->variableList()) {
bool known = true;
if (!var || !var->isLocal() || var->isPointer() || var->isReference() || var->isStatic())
continue;
if (!var->valueType() || !var->valueType()->container)
continue;
if (!astIsContainer(var->nameToken()))
continue;
if (var->nameToken()->hasKnownValue(ValueFlow::Value::ValueType::CONTAINER_SIZE))
continue;
if (!Token::Match(var->nameToken(), "%name% ;") &&
!(Token::Match(var->nameToken(), "%name% {") && Token::simpleMatch(var->nameToken()->next()->link(), "} ;")))
continue;
if (var->nameToken()->astTop() && Token::Match(var->nameToken()->astTop()->previous(), "for|while"))
known = !isVariableChanged(var, settings, true);
if (var->valueType()->container->size_templateArgNo >= 0) {
if (var->dimensions().size() == 1 && var->dimensions().front().known)
static_sizes[var->declarationId()] = var->dimensions().front().num;
continue;
}
std::vector<ValueFlow::Value> values{ValueFlow::Value{0}};
values.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
if (known)
values.back().setKnown();
if (Token::simpleMatch(var->nameToken()->next(), "{")) {
const Token* initList = var->nameToken()->next();
values = getInitListSize(initList, var->valueType()->container, known);
}
for (const ValueFlow::Value& value : values)
valueFlowContainerForward(var->nameToken()->next(), var->nameToken(), value, tokenlist);
}
// after assignment
for (const Scope *functionScope : symboldatabase->functionScopes) {
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
if (static_sizes.count(tok->varId()) > 0) {
ValueFlow::Value value(static_sizes.at(tok->varId()));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
setTokenValue(const_cast<Token*>(tok), value, settings);
} else if (Token::Match(tok, "%name%|;|{|} %var% = %str% ;")) {
const Token *containerTok = tok->next();
if (containerTok->exprId() == 0)
continue;
if (containerTok->valueType() && containerTok->valueType()->container && containerTok->valueType()->container->stdStringLike) {
ValueFlow::Value value(Token::getStrLength(containerTok->tokAt(2)));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
value.setKnown();
valueFlowContainerForward(containerTok->next(), containerTok, value, tokenlist);
}
} else if (Token::Match(tok, "%name%|;|{|}|> %var% = {") && Token::simpleMatch(tok->linkAt(3), "} ;")) {
const 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()->container);
for (const ValueFlow::Value& value : values)
valueFlowContainerForward(containerTok->next(), containerTok, value, tokenlist);
}
} 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;
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();
valueFlowContainerForward(tok->next(), containerTok, value, tokenlist);
} 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();
valueFlowContainerForward(tok->next(), containerTok, value, tokenlist);
}
}
}
}
}
struct ContainerConditionHandler : ConditionHandler {
virtual Analyzer::Result forward(Token* start,
const Token* stop,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings*) const override {
Analyzer::Result result{};
for (const ValueFlow::Value& value : values)
result.update(valueFlowContainerForward(start->next(), stop, exprTok, value, tokenlist));
return result;
}
virtual Analyzer::Result forward(Token* top,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings*) const override {
Analyzer::Result result{};
for (const ValueFlow::Value& value : values)
result.update(valueFlowContainerForwardRecursive(top, exprTok, value, tokenlist));
return result;
}
virtual void reverse(Token* start,
const Token* endTok,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
TokenList* tokenlist,
const Settings* settings) const override {
return valueFlowContainerReverse(start, endTok, exprTok, values, tokenlist, settings);
}
virtual std::vector<Condition> parse(const Token* tok, const Settings* settings) const override
{
Condition cond;
ValueFlow::Value true_value;
ValueFlow::Value false_value;
const Token *vartok = parseCompareInt(tok, true_value, false_value);
if (vartok) {
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;
cond.true_values.push_back(true_value);
cond.false_values.push_back(false_value);
cond.vartok = vartok;
return {cond};
}
// Empty check
if (tok->str() == "(") {
vartok = 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;
cond.true_values.emplace_back(value);
cond.false_values.emplace_back(std::move(value));
cond.vartok = vartok;
cond.inverted = true;
return {cond};
}
// String compare
if (Token::Match(tok, "==|!=")) {
const Token *strtok = nullptr;
if (Token::Match(tok->astOperand1(), "%str%")) {
strtok = tok->astOperand1();
vartok = tok->astOperand2();
} else if (Token::Match(tok->astOperand2(), "%str%")) {
strtok = tok->astOperand2();
vartok = tok->astOperand1();
}
if (!strtok)
return {};
if (!astIsContainer(vartok))
return {};
ValueFlow::Value value(tok, Token::getStrLength(strtok));
value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
cond.false_values.emplace_back(value);
cond.true_values.emplace_back(std::move(value));
cond.vartok = vartok;
cond.impossible = false;
return {cond};
}
return {};
}
};
static void valueFlowDynamicBufferSize(TokenList* tokenlist, SymbolDatabase* symboldatabase, const Settings* settings)
{
for (const Scope *functionScope : symboldatabase->functionScopes) {
for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "[;{}] %var% ="))
continue;
if (!tok->next()->variable())
continue;
const Token *rhs = tok->tokAt(2)->astOperand2();
while (rhs && rhs->isCast())
rhs = rhs->astOperand2() ? rhs->astOperand2() : rhs->astOperand1();
if (!rhs)
continue;
if (!Token::Match(rhs->previous(), "%name% ("))
continue;
const Library::AllocFunc *allocFunc = settings->library.getAllocFuncInfo(rhs->previous());
if (!allocFunc)
allocFunc = settings->library.getReallocFuncInfo(rhs->previous());
if (!allocFunc || allocFunc->bufferSize == Library::AllocFunc::BufferSize::none)
continue;
const std::vector<const Token *> args = getArguments(rhs->previous());
const Token * const arg1 = (args.size() >= allocFunc->bufferSizeArg1) ? args[allocFunc->bufferSizeArg1 - 1] : nullptr;
const Token * const arg2 = (args.size() >= allocFunc->bufferSizeArg2) ? args[allocFunc->bufferSizeArg2 - 1] : nullptr;
MathLib::bigint sizeValue = -1;
switch (allocFunc->bufferSize) {
case Library::AllocFunc::BufferSize::none:
break;
case Library::AllocFunc::BufferSize::malloc:
if (arg1 && arg1->hasKnownIntValue())
sizeValue = arg1->getKnownIntValue();
break;
case Library::AllocFunc::BufferSize::calloc:
if (arg1 && arg2 && arg1->hasKnownIntValue() && arg2->hasKnownIntValue())
sizeValue = arg1->getKnownIntValue() * arg2->getKnownIntValue();
break;
case Library::AllocFunc::BufferSize::strdup:
if (arg1 && arg1->hasKnownValue()) {
const ValueFlow::Value &value = arg1->values().back();
if (value.isTokValue() && value.tokvalue->tokType() == Token::eString)
sizeValue = Token::getStrLength(value.tokvalue) + 1; // Add one for the null terminator
}
break;
}
if (sizeValue < 0)
continue;
ValueFlow::Value value(sizeValue);
value.errorPath.emplace_back(tok->tokAt(2), "Assign " + tok->strAt(1) + ", buffer with size " + MathLib::toString(sizeValue));
value.valueType = ValueFlow::Value::ValueType::BUFFER_SIZE;
value.setKnown();
const std::list<ValueFlow::Value> values{value};
valueFlowForward(const_cast<Token*>(rhs), functionScope->bodyEnd, tok->next(), values, tokenlist, settings);
}
}
}
static bool getMinMaxValues(const ValueType *vt, const cppcheck::Platform &platform, MathLib::bigint *minValue, MathLib::bigint *maxValue)
{
if (!vt || !vt->isIntegral() || vt->pointer)
return false;
int bits;
switch (vt->type) {
case ValueType::Type::BOOL:
bits = 1;
break;
case ValueType::Type::CHAR:
bits = platform.char_bit;
break;
case ValueType::Type::SHORT:
bits = platform.short_bit;
break;
case ValueType::Type::INT:
bits = platform.int_bit;
break;
case ValueType::Type::LONG:
bits = platform.long_bit;
break;
case ValueType::Type::LONGLONG:
bits = platform.long_long_bit;
break;
default:
return false;
}
if (bits == 1) {
*minValue = 0;
*maxValue = 1;
} else if (bits < 62) {
if (vt->sign == ValueType::Sign::UNSIGNED) {
*minValue = 0;
*maxValue = (1LL << bits) - 1;
} else {
*minValue = -(1LL << (bits - 1));
*maxValue = (1LL << (bits - 1)) - 1;
}
} else if (bits == 64) {
if (vt->sign == ValueType::Sign::UNSIGNED) {
*minValue = 0;
*maxValue = LLONG_MAX; // todo max unsigned value
} else {
*minValue = LLONG_MIN;
*maxValue = LLONG_MAX;
}
} else {
return false;
}
return true;
}
static bool getMinMaxValues(const std::string &typestr, const Settings *settings, MathLib::bigint *minvalue, MathLib::bigint *maxvalue)
{
TokenList typeTokens(settings);
std::istringstream istr(typestr+";");
if (!typeTokens.createTokens(istr))
return false;
typeTokens.simplifyPlatformTypes();
typeTokens.simplifyStdType();
const ValueType &vt = ValueType::parseDecl(typeTokens.front(), settings);
return getMinMaxValues(&vt, *settings, minvalue, maxvalue);
}
static void valueFlowSafeFunctions(TokenList* tokenlist, SymbolDatabase* symboldatabase, const Settings* settings)
{
for (const Scope *functionScope : symboldatabase->functionScopes) {
if (!functionScope->bodyStart)
continue;
const Function *function = functionScope->function;
if (!function)
continue;
const bool safe = function->isSafe(settings);
const bool all = safe && settings->platformType != cppcheck::Platform::PlatformType::Unspecified;
for (const Variable &arg : function->argumentList) {
if (!arg.nameToken() || !arg.valueType())
continue;
if (arg.valueType()->type == ValueType::Type::CONTAINER) {
if (!safe)
continue;
std::list<ValueFlow::Value> argValues;
argValues.emplace_back(0);
argValues.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Assuming " + arg.name() + " is empty");
argValues.back().safe = true;
argValues.emplace_back(1000000);
argValues.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Assuming " + arg.name() + " size is 1000000");
argValues.back().safe = true;
for (const ValueFlow::Value &value : argValues)
valueFlowContainerForward(
const_cast<Token*>(functionScope->bodyStart), arg.nameToken(), value, tokenlist);
continue;
}
MathLib::bigint low, high;
bool isLow = arg.nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::LOW, &low);
bool isHigh = arg.nameToken()->getCppcheckAttribute(TokenImpl::CppcheckAttributes::Type::HIGH, &high);
if (!isLow && !isHigh && !all)
continue;
const bool safeLow = !isLow;
const bool safeHigh = !isHigh;
if ((!isLow || !isHigh) && all) {
MathLib::bigint minValue, maxValue;
if (getMinMaxValues(arg.valueType(), *settings, &minValue, &maxValue)) {
if (!isLow)
low = minValue;
if (!isHigh)
high = maxValue;
isLow = isHigh = true;
} else if (arg.valueType()->type == ValueType::Type::FLOAT || arg.valueType()->type == ValueType::Type::DOUBLE || arg.valueType()->type == ValueType::Type::LONGDOUBLE) {
std::list<ValueFlow::Value> argValues;
argValues.emplace_back(0);
argValues.back().valueType = ValueFlow::Value::ValueType::FLOAT;
argValues.back().floatValue = isLow ? low : -1E25f;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue));
argValues.back().safe = true;
argValues.emplace_back(0);
argValues.back().valueType = ValueFlow::Value::ValueType::FLOAT;
argValues.back().floatValue = isHigh ? high : 1E25f;
argValues.back().errorPath.emplace_back(arg.nameToken(), "Safe checks: Assuming argument has value " + MathLib::toString(argValues.back().floatValue));
argValues.back().safe = true;
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 " + MathLib::toString(low));
argValues.back().safe = safeLow;
}
if (isHigh) {
argValues.emplace_back(high);
argValues.back().errorPath.emplace_back(arg.nameToken(), std::string(safeHigh ? "Safe checks: " : "") + "Assuming argument has value " + MathLib::toString(high));
argValues.back().safe = safeHigh;
}
if (!argValues.empty())
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(const_cast<Token *>(tok), ValueFlow::Value(value), settings);
}
}
}
ValueFlow::Value::Value(const Token* c, long long val, Bound b)
: valueType(ValueType::INT),
bound(b),
intvalue(val),
tokvalue(nullptr),
floatValue(0.0),
moveKind(MoveKind::NonMovedVariable),
varvalue(val),
condition(c),
varId(0),
safe(false),
conditional(false),
macro(false),
defaultArg(false),
indirect(0),
path(0),
wideintvalue(0),
subexpressions(),
lifetimeKind(LifetimeKind::Object),
lifetimeScope(LifetimeScope::Local),
valueKind(ValueKind::Possible)
{
errorPath.emplace_back(c, "Assuming that condition '" + c->expressionString() + "' is not redundant");
}
void ValueFlow::Value::assumeCondition(const Token* tok)
{
condition = tok;
errorPath.emplace_back(tok, "Assuming that condition '" + tok->expressionString() + "' is not redundant");
}
std::string ValueFlow::Value::infoString() const
{
switch (valueType) {
case ValueType::INT:
return MathLib::toString(intvalue);
case ValueType::TOK:
return tokvalue->str();
case ValueType::FLOAT:
return MathLib::toString(floatValue);
case ValueType::MOVED:
return "<Moved>";
case ValueType::UNINIT:
return "<Uninit>";
case ValueType::BUFFER_SIZE:
case ValueType::CONTAINER_SIZE:
return "size=" + MathLib::toString(intvalue);
case ValueType::ITERATOR_START:
return "start=" + MathLib::toString(intvalue);
case ValueType::ITERATOR_END:
return "end=" + MathLib::toString(intvalue);
case ValueType::LIFETIME:
return "lifetime=" + tokvalue->str();
case ValueType::SYMBOLIC:
std::string result = "symbolic=" + tokvalue->expressionString();
if (intvalue > 0)
result += "+" + MathLib::toString(intvalue);
else if (intvalue < 0)
result += "-" + MathLib::toString(-intvalue);
return result;
}
throw InternalError(nullptr, "Invalid ValueFlow Value type");
}
const char* ValueFlow::Value::toString(MoveKind moveKind)
{
switch (moveKind) {
case MoveKind::NonMovedVariable:
return "NonMovedVariable";
case MoveKind::MovedVariable:
return "MovedVariable";
case MoveKind::ForwardedVariable:
return "ForwardedVariable";
}
return "";
}
const char* ValueFlow::Value::toString(LifetimeKind lifetimeKind)
{
switch (lifetimeKind) {
case LifetimeKind::Object:
return "Object";
case LifetimeKind::SubObject:
return "SubObject";
case LifetimeKind::Lambda:
return "Lambda";
case LifetimeKind::Iterator:
return "Iterator";
case LifetimeKind::Address:
return "Address";
}
return "";
}
bool ValueFlow::Value::sameToken(const Token* tok1, const Token* tok2)
{
if (tok1 == tok2)
return true;
if (!tok1)
return false;
if (tok1->exprId() == 0 || tok2->exprId() == 0)
return false;
return tok1->exprId() == tok2->exprId();
}
const char* ValueFlow::Value::toString(LifetimeScope lifetimeScope)
{
switch (lifetimeScope) {
case ValueFlow::Value::LifetimeScope::Local:
return "Local";
case ValueFlow::Value::LifetimeScope::Argument:
return "Argument";
case ValueFlow::Value::LifetimeScope::SubFunction:
return "SubFunction";
}
return "";
}
const char* ValueFlow::Value::toString(Bound bound)
{
switch (bound) {
case ValueFlow::Value::Bound::Point:
return "Point";
case ValueFlow::Value::Bound::Upper:
return "Upper";
case ValueFlow::Value::Bound::Lower:
return "Lower";
}
return "";
}
const ValueFlow::Value *ValueFlow::valueFlowConstantFoldAST(Token *expr, const Settings *settings)
{
if (expr && expr->values().empty()) {
valueFlowConstantFoldAST(expr->astOperand1(), settings);
valueFlowConstantFoldAST(expr->astOperand2(), settings);
valueFlowSetConstantValue(expr, settings, true /* TODO: this is a guess */);
}
return expr && expr->hasKnownValue() ? &expr->values().front() : nullptr;
}
static std::size_t getTotalValues(TokenList *tokenlist)
{
std::size_t n = 1;
for (Token *tok = tokenlist->front(); tok; tok = tok->next())
n += tok->values().size();
return n;
}
void ValueFlow::setValues(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next())
tok->clearValueFlow();
valueFlowEnumValue(symboldatabase, settings);
valueFlowNumber(tokenlist);
valueFlowString(tokenlist);
valueFlowArray(tokenlist);
valueFlowUnknownFunctionReturn(tokenlist, settings);
valueFlowGlobalConstVar(tokenlist, settings);
valueFlowEnumValue(symboldatabase, settings);
valueFlowNumber(tokenlist);
valueFlowGlobalStaticVar(tokenlist, settings);
valueFlowPointerAlias(tokenlist);
valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings);
valueFlowSymbolic(tokenlist, symboldatabase);
valueFlowBitAnd(tokenlist);
valueFlowSameExpressions(tokenlist);
valueFlowConditionExpressions(tokenlist, symboldatabase, errorLogger, settings);
std::size_t values = 0;
std::size_t n = 4;
while (n > 0 && values < getTotalValues(tokenlist)) {
values = getTotalValues(tokenlist);
valueFlowImpossibleValues(tokenlist, settings);
valueFlowSymbolicIdentity(tokenlist);
valueFlowSymbolicAbs(tokenlist, symboldatabase);
valueFlowCondition(SymbolicConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings);
valueFlowSymbolicInfer(tokenlist, symboldatabase);
valueFlowArrayBool(tokenlist);
valueFlowRightShift(tokenlist, settings);
valueFlowAfterAssign(tokenlist, symboldatabase, errorLogger, settings);
valueFlowAfterSwap(tokenlist, symboldatabase, errorLogger, settings);
valueFlowCondition(SimpleConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings);
valueFlowInferCondition(tokenlist, settings);
valueFlowSwitchVariable(tokenlist, symboldatabase, errorLogger, settings);
valueFlowForLoop(tokenlist, symboldatabase, errorLogger, settings);
valueFlowSubFunction(tokenlist, symboldatabase, errorLogger, settings);
valueFlowFunctionReturn(tokenlist, errorLogger);
valueFlowLifetime(tokenlist, symboldatabase, errorLogger, settings);
valueFlowFunctionDefaultParameter(tokenlist, symboldatabase, settings);
valueFlowUninit(tokenlist, symboldatabase, settings);
if (tokenlist->isCPP()) {
valueFlowAfterMove(tokenlist, symboldatabase, settings);
valueFlowSmartPointer(tokenlist, errorLogger, settings);
valueFlowIterators(tokenlist, settings);
valueFlowCondition(IteratorConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings);
valueFlowIteratorInfer(tokenlist, settings);
valueFlowContainerSize(tokenlist, symboldatabase, errorLogger, settings);
valueFlowCondition(ContainerConditionHandler{}, tokenlist, symboldatabase, errorLogger, settings);
}
valueFlowSafeFunctions(tokenlist, symboldatabase, settings);
n--;
}
valueFlowDynamicBufferSize(tokenlist, symboldatabase, settings);
}
ValueFlow::Value ValueFlow::Value::unknown()
{
Value v;
v.valueType = Value::ValueType::UNINIT;
return v;
}
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,
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;
}
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().begin(), indexTok->values().end(), [&](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 {};
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 {value};
}
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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