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valueflow.cpp
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2024 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @brief This is the ValueFlow component in Cppcheck.
*
* Each @sa Token in the token list has a list of values. These are
* the "possible" values for the Token at runtime.
*
* In the --debug and --debug-normal output you can see the ValueFlow data. For example:
*
* int f()
* {
* int x = 10;
* return 4 * x + 2;
* }
*
* The --debug-normal output says:
*
* ##Value flow
* Line 3
* 10 always 10
* Line 4
* 4 always 4
* * always 40
* x always 10
* + always 42
* 2 always 2
*
* All value flow analysis is executed in the ValueFlow::setValues() function. The ValueFlow analysis is executed after
* the tokenizer/ast/symboldatabase/etc.. The ValueFlow analysis is done in a series of valueFlow* function calls, where
* each such function call can only use results from previous function calls. The function calls should be arranged so
* that valueFlow* that do not require previous ValueFlow information should be first.
*
* Type of analysis
* ================
*
* This is "flow sensitive" value flow analysis. We _usually_ track the value for 1 variable at a time.
*
* How are calculations handled
* ============================
*
* Here is an example code:
*
* x = 3 + 4;
*
* The valueFlowNumber set the values for the "3" and "4" tokens by calling setTokenValue().
* The setTokenValue() handle the calculations automatically. When both "3" and "4" have values, the "+" can be
* calculated. setTokenValue() recursively calls itself when parents in calculations can be calculated.
*
* Forward / Reverse flow analysis
* ===============================
*
* In forward value flow analysis we know a value and see what happens when we are stepping the program forward. Like
* normal execution. The valueFlowForward is used in this analysis.
*
* In reverse value flow analysis we know the value of a variable at line X. And try to "execute backwards" to determine
* possible values before line X. The valueFlowReverse is used in this analysis.
*
*
*/
#include "valueflow.h"
#include "analyzer.h"
#include "astutils.h"
#include "calculate.h"
#include "checkuninitvar.h"
#include "config.h"
#include "errorlogger.h"
#include "errortypes.h"
#include "findtoken.h"
#include "forwardanalyzer.h"
#include "infer.h"
#include "library.h"
#include "mathlib.h"
#include "path.h"
#include "platform.h"
#include "programmemory.h"
#include "reverseanalyzer.h"
#include "settings.h"
#include "smallvector.h"
#include "sourcelocation.h"
#include "standards.h"
#include "symboldatabase.h"
#include "timer.h"
#include "token.h"
#include "tokenlist.h"
#include "utils.h"
#include "valueptr.h"
#include "vfvalue.h"
#include "vf_analyzers.h"
#include "vf_common.h"
#include "vf_settokenvalue.h"
#include <algorithm>
#include <array>
#include <cassert>
#include <chrono>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <initializer_list>
#include <iterator>
#include <limits>
#include <map>
#include <memory>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
static void bailoutInternal(const std::string& type,
const TokenList& tokenlist,
ErrorLogger& errorLogger,
const Token* tok,
const std::string& what,
const std::string& file,
int line,
std::string function)
{
if (function.find("operator") != std::string::npos)
function = "(valueFlow)";
ErrorMessage::FileLocation loc(tok, &tokenlist);
const std::string location = Path::stripDirectoryPart(file) + ":" + std::to_string(line) + ":";
ErrorMessage errmsg({std::move(loc)},
tokenlist.getSourceFilePath(),
Severity::debug,
(file.empty() ? "" : location) + function + " bailout: " + what,
type,
Certainty::normal);
errorLogger.reportErr(errmsg);
}
#define bailout2(type, tokenlist, errorLogger, tok, what) \
bailoutInternal((type), (tokenlist), (errorLogger), (tok), (what), __FILE__, __LINE__, __func__)
#define bailout(tokenlist, errorLogger, tok, what) \
bailout2("valueFlowBailout", (tokenlist), (errorLogger), (tok), (what))
#define bailoutIncompleteVar(tokenlist, errorLogger, tok, what) \
bailoutInternal("valueFlowBailoutIncompleteVar", (tokenlist), (errorLogger), (tok), (what), "", 0, __func__)
static void changeKnownToPossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
for (ValueFlow::Value& v : values) {
if (indirect >= 0 && v.indirect != indirect)
continue;
v.changeKnownToPossible();
}
}
static void removeImpossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
values.remove_if([&](const ValueFlow::Value& v) {
if (indirect >= 0 && v.indirect != indirect)
return false;
return v.isImpossible();
});
}
static void lowerToPossible(std::list<ValueFlow::Value>& values, int indirect = -1)
{
changeKnownToPossible(values, indirect);
removeImpossible(values, indirect);
}
static void changePossibleToKnown(std::list<ValueFlow::Value>& values, int indirect = -1)
{
for (ValueFlow::Value& v : values) {
if (indirect >= 0 && v.indirect != indirect)
continue;
if (!v.isPossible())
continue;
if (v.bound != ValueFlow::Value::Bound::Point)
continue;
v.setKnown();
}
}
static bool isNonConditionalPossibleIntValue(const ValueFlow::Value& v)
{
if (v.conditional)
return false;
if (v.condition)
return false;
if (!v.isPossible())
return false;
if (!v.isIntValue())
return false;
return true;
}
static void setValueUpperBound(ValueFlow::Value& value, bool upper)
{
if (upper)
value.bound = ValueFlow::Value::Bound::Upper;
else
value.bound = ValueFlow::Value::Bound::Lower;
}
static void setValueBound(ValueFlow::Value& value, const Token* tok, bool invert)
{
if (Token::Match(tok, "<|<=")) {
setValueUpperBound(value, !invert);
} else if (Token::Match(tok, ">|>=")) {
setValueUpperBound(value, invert);
}
}
static void setConditionalValue(ValueFlow::Value& value, const Token* tok, MathLib::bigint i)
{
assert(value.isIntValue());
value.intvalue = i;
value.assumeCondition(tok);
value.setPossible();
}
static void setConditionalValues(const Token* tok,
bool lhs,
MathLib::bigint value,
ValueFlow::Value& true_value,
ValueFlow::Value& false_value)
{
if (Token::Match(tok, "==|!=|>=|<=")) {
setConditionalValue(true_value, tok, value);
const char* greaterThan = ">=";
const char* lessThan = "<=";
if (lhs)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
setConditionalValue(false_value, tok, value - 1);
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
setConditionalValue(false_value, tok, value + 1);
} else {
setConditionalValue(false_value, tok, value);
}
} else {
const char* greaterThan = ">";
const char* lessThan = "<";
if (lhs)
std::swap(greaterThan, lessThan);
if (Token::simpleMatch(tok, greaterThan, strlen(greaterThan))) {
setConditionalValue(true_value, tok, value + 1);
setConditionalValue(false_value, tok, value);
} else if (Token::simpleMatch(tok, lessThan, strlen(lessThan))) {
setConditionalValue(true_value, tok, value - 1);
setConditionalValue(false_value, tok, value);
}
}
setValueBound(true_value, tok, lhs);
setValueBound(false_value, tok, !lhs);
}
static bool isSaturated(MathLib::bigint value)
{
return value == std::numeric_limits<MathLib::bigint>::max() || value == std::numeric_limits<MathLib::bigint>::min();
}
static void parseCompareEachInt(
const Token* tok,
const std::function<void(const Token* varTok, ValueFlow::Value true_value, ValueFlow::Value false_value)>& each,
const std::function<std::vector<ValueFlow::Value>(const Token*)>& evaluate)
{
if (!tok->astOperand1() || !tok->astOperand2())
return;
if (tok->isComparisonOp()) {
std::vector<ValueFlow::Value> value1 = evaluate(tok->astOperand1());
std::vector<ValueFlow::Value> value2 = evaluate(tok->astOperand2());
if (!value1.empty() && !value2.empty()) {
if (tok->astOperand1()->hasKnownIntValue())
value2.clear();
if (tok->astOperand2()->hasKnownIntValue())
value1.clear();
}
for (const ValueFlow::Value& v1 : value1) {
if (isSaturated(v1.intvalue) || astIsFloat(tok->astOperand2(), /*unknown*/ false))
continue;
ValueFlow::Value true_value = v1;
ValueFlow::Value false_value = v1;
setConditionalValues(tok, true, v1.intvalue, true_value, false_value);
each(tok->astOperand2(), std::move(true_value), std::move(false_value));
}
for (const ValueFlow::Value& v2 : value2) {
if (isSaturated(v2.intvalue) || astIsFloat(tok->astOperand1(), /*unknown*/ false))
continue;
ValueFlow::Value true_value = v2;
ValueFlow::Value false_value = v2;
setConditionalValues(tok, false, v2.intvalue, true_value, false_value);
each(tok->astOperand1(), std::move(true_value), std::move(false_value));
}
}
}
static void parseCompareEachInt(
const Token* tok,
const std::function<void(const Token* varTok, ValueFlow::Value true_value, ValueFlow::Value false_value)>& each)
{
parseCompareEachInt(tok, each, [](const Token* t) -> std::vector<ValueFlow::Value> {
if (t->hasKnownIntValue())
return {t->values().front()};
std::vector<ValueFlow::Value> result;
std::copy_if(t->values().cbegin(), t->values().cend(), std::back_inserter(result), [&](const ValueFlow::Value& v) {
if (v.path < 1)
return false;
if (!isNonConditionalPossibleIntValue(v))
return false;
return true;
});
return result;
});
}
const Token* ValueFlow::parseCompareInt(const Token* tok,
ValueFlow::Value& true_value,
ValueFlow::Value& false_value,
const std::function<std::vector<MathLib::bigint>(const Token*)>& evaluate)
{
const Token* result = nullptr;
parseCompareEachInt(
tok,
[&](const Token* vartok, ValueFlow::Value true_value2, ValueFlow::Value false_value2) {
if (result)
return;
result = vartok;
true_value = std::move(true_value2);
false_value = std::move(false_value2);
},
[&](const Token* t) -> std::vector<ValueFlow::Value> {
std::vector<ValueFlow::Value> r;
std::vector<MathLib::bigint> v = evaluate(t);
std::transform(v.cbegin(), v.cend(), std::back_inserter(r), [&](MathLib::bigint i) {
return ValueFlow::Value{i};
});
return r;
});
return result;
}
const Token *ValueFlow::parseCompareInt(const Token *tok, ValueFlow::Value &true_value, ValueFlow::Value &false_value)
{
return parseCompareInt(tok, true_value, false_value, [](const Token* t) -> std::vector<MathLib::bigint> {
if (t->hasKnownIntValue())
return {t->values().front().intvalue};
return std::vector<MathLib::bigint>{};
});
}
static bool isEscapeScope(const Token* tok, const Settings& settings, bool unknown = false)
{
if (!Token::simpleMatch(tok, "{"))
return false;
// TODO this search for termTok in all subscopes. It should check the end of the scope.
const Token* termTok = Token::findmatch(tok, "return|continue|break|throw|goto", tok->link());
if (termTok && termTok->scope() == tok->scope())
return true;
std::string unknownFunction;
if (settings.library.isScopeNoReturn(tok->link(), &unknownFunction))
return unknownFunction.empty() || unknown;
return false;
}
void ValueFlow::combineValueProperties(const ValueFlow::Value &value1, const ValueFlow::Value &value2, ValueFlow::Value &result)
{
if (value1.isKnown() && value2.isKnown())
result.setKnown();
else if (value1.isImpossible() || value2.isImpossible())
result.setImpossible();
else if (value1.isInconclusive() || value2.isInconclusive())
result.setInconclusive();
else
result.setPossible();
if (value1.tokvalue)
result.tokvalue = value1.tokvalue;
else if (value2.tokvalue)
result.tokvalue = value2.tokvalue;
if (value1.isSymbolicValue()) {
result.valueType = value1.valueType;
result.tokvalue = value1.tokvalue;
}
if (value2.isSymbolicValue()) {
result.valueType = value2.valueType;
result.tokvalue = value2.tokvalue;
}
if (value1.isIteratorValue())
result.valueType = value1.valueType;
if (value2.isIteratorValue())
result.valueType = value2.valueType;
result.condition = value1.condition ? value1.condition : value2.condition;
result.varId = (value1.varId != 0) ? value1.varId : value2.varId;
result.varvalue = (result.varId == value1.varId) ? value1.varvalue : value2.varvalue;
result.errorPath = (value1.errorPath.empty() ? value2 : value1).errorPath;
result.safe = value1.safe || value2.safe;
if (value1.bound == ValueFlow::Value::Bound::Point || value2.bound == ValueFlow::Value::Bound::Point) {
if (value1.bound == ValueFlow::Value::Bound::Upper || value2.bound == ValueFlow::Value::Bound::Upper)
result.bound = ValueFlow::Value::Bound::Upper;
if (value1.bound == ValueFlow::Value::Bound::Lower || value2.bound == ValueFlow::Value::Bound::Lower)
result.bound = ValueFlow::Value::Bound::Lower;
}
if (value1.path != value2.path)
result.path = -1;
else
result.path = value1.path;
}
template<class F>
static size_t accumulateStructMembers(const Scope* scope, F f)
{
size_t total = 0;
std::set<const Scope*> anonScopes;
for (const Variable& var : scope->varlist) {
if (var.isStatic())
continue;
if (const ValueType* vt = var.valueType()) {
if (vt->type == ValueType::Type::RECORD && vt->typeScope == scope)
return 0;
const MathLib::bigint dim = std::accumulate(var.dimensions().cbegin(), var.dimensions().cend(), 1LL, [](MathLib::bigint i1, const Dimension& dim) {
return i1 * dim.num;
});
if (var.nameToken()->scope() != scope && var.nameToken()->scope()->definedType) { // anonymous union
const auto ret = anonScopes.insert(var.nameToken()->scope());
if (ret.second)
total = f(total, *vt, dim);
}
else
total = f(total, *vt, dim);
}
if (total == 0)
return 0;
}
return total;
}
static size_t bitCeil(size_t x)
{
if (x <= 1)
return 1;
--x;
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
x |= x >> 32;
return x + 1;
}
static size_t getAlignOf(const ValueType& vt, const Settings& settings, int maxRecursion = 0)
{
if (maxRecursion == settings.vfOptions.maxAlignOfRecursion) {
// TODO: add bailout message
return 0;
}
if (vt.pointer || vt.reference != Reference::None || vt.isPrimitive()) {
auto align = ValueFlow::getSizeOf(vt, settings);
return align == 0 ? 0 : bitCeil(align);
}
if (vt.type == ValueType::Type::RECORD && vt.typeScope) {
auto accHelper = [&](size_t max, const ValueType& vt2, size_t /*dim*/) {
size_t a = getAlignOf(vt2, settings, ++maxRecursion);
return std::max(max, a);
};
size_t total = 0;
if (const Type* dt = vt.typeScope->definedType) {
total = std::accumulate(dt->derivedFrom.begin(), dt->derivedFrom.end(), total, [&](size_t v, const Type::BaseInfo& bi) {
if (bi.type && bi.type->classScope)
v += accumulateStructMembers(bi.type->classScope, accHelper);
return v;
});
}
return total + accumulateStructMembers(vt.typeScope, accHelper);
}
if (vt.type == ValueType::Type::CONTAINER)
return settings.platform.sizeof_pointer; // Just guess
return 0;
}
size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings &settings, int maxRecursion)
{
if (maxRecursion == settings.vfOptions.maxSizeOfRecursion) {
// TODO: add bailout message
return 0;
}
if (vt.pointer || vt.reference != Reference::None)
return settings.platform.sizeof_pointer;
if (vt.type == ValueType::Type::BOOL || vt.type == ValueType::Type::CHAR)
return 1;
if (vt.type == ValueType::Type::SHORT)
return settings.platform.sizeof_short;
if (vt.type == ValueType::Type::WCHAR_T)
return settings.platform.sizeof_wchar_t;
if (vt.type == ValueType::Type::INT)
return settings.platform.sizeof_int;
if (vt.type == ValueType::Type::LONG)
return settings.platform.sizeof_long;
if (vt.type == ValueType::Type::LONGLONG)
return settings.platform.sizeof_long_long;
if (vt.type == ValueType::Type::FLOAT)
return settings.platform.sizeof_float;
if (vt.type == ValueType::Type::DOUBLE)
return settings.platform.sizeof_double;
if (vt.type == ValueType::Type::LONGDOUBLE)
return settings.platform.sizeof_long_double;
if (vt.type == ValueType::Type::CONTAINER)
return 3 * settings.platform.sizeof_pointer; // Just guess
if (vt.type == ValueType::Type::RECORD && vt.typeScope) {
auto accHelper = [&](size_t total, const ValueType& vt2, size_t dim) -> size_t {
size_t n = ValueFlow::getSizeOf(vt2, settings, ++maxRecursion);
size_t a = getAlignOf(vt2, settings);
if (n == 0 || a == 0)
return 0;
n *= dim;
size_t padding = (a - (total % a)) % a;
return vt.typeScope->type == Scope::eUnion ? std::max(total, n) : total + padding + n;
};
size_t total = accumulateStructMembers(vt.typeScope, accHelper);
if (const Type* dt = vt.typeScope->definedType) {
total = std::accumulate(dt->derivedFrom.begin(), dt->derivedFrom.end(), total, [&](size_t v, const Type::BaseInfo& bi) {
if (bi.type && bi.type->classScope)
v += accumulateStructMembers(bi.type->classScope, accHelper);
return v;
});
}
if (total == 0)
return 0;
size_t align = getAlignOf(vt, settings);
if (align == 0)
return 0;
total += (align - (total % align)) % align;
return total;
}
return 0;
}
static void valueFlowNumber(TokenList &tokenlist, const Settings& settings)
{
for (Token *tok = tokenlist.front(); tok;) {
tok = ValueFlow::valueFlowSetConstantValue(tok, settings);
}
if (tokenlist.isCPP() || settings.standards.c >= Standards::C23) {
for (Token *tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->isName() && !tok->varId() && Token::Match(tok, "false|true")) {
ValueFlow::Value value(tok->str() == "true");
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok, std::move(value), settings);
} else if (Token::Match(tok, "[(,] NULL [,)]")) {
// NULL function parameters are not simplified in the
// normal tokenlist
ValueFlow::Value value(0);
if (!tok->isTemplateArg())
value.setKnown();
setTokenValue(tok->next(), std::move(value), settings);
}
}
}
}
static void valueFlowString(TokenList& tokenlist, const Settings& settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->tokType() == Token::eString) {
ValueFlow::Value strvalue;
strvalue.valueType = ValueFlow::Value::ValueType::TOK;
strvalue.tokvalue = tok;
strvalue.setKnown();
setTokenValue(tok, std::move(strvalue), settings);
}
}
}
static void valueFlowArray(TokenList& tokenlist, const Settings& settings)
{
std::map<nonneg int, const Token*> constantArrays;
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->varId() > 0) {
// array
const auto it = utils::as_const(constantArrays).find(tok->varId());
if (it != constantArrays.end()) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = it->second;
value.setKnown();
setTokenValue(tok, std::move(value), settings);
}
// const array decl
else if (tok->variable() && tok->variable()->isArray() && tok->variable()->isConst() &&
tok->variable()->nameToken() == tok && Token::Match(tok, "%var% [ %num%| ] = {")) {
Token* rhstok = tok->linkAt(1)->tokAt(2);
constantArrays[tok->varId()] = rhstok;
tok = rhstok->link();
}
// pointer = array
else if (tok->variable() && tok->variable()->isArray() && Token::simpleMatch(tok->astParent(), "=") &&
astIsRHS(tok) && tok->astParent()->astOperand1() && tok->astParent()->astOperand1()->variable() &&
tok->astParent()->astOperand1()->variable()->isPointer()) {
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = tok;
value.setKnown();
setTokenValue(tok, std::move(value), settings);
}
continue;
}
if (Token::Match(tok, "const %type% %var% [ %num%| ] = {")) {
Token* vartok = tok->tokAt(2);
Token* rhstok = vartok->linkAt(1)->tokAt(2);
constantArrays[vartok->varId()] = rhstok;
tok = rhstok->link();
continue;
}
if (Token::Match(tok, "const char %var% [ %num%| ] = %str% ;")) {
Token* vartok = tok->tokAt(2);
Token* strtok = vartok->linkAt(1)->tokAt(2);
constantArrays[vartok->varId()] = strtok;
tok = strtok->next();
continue;
}
}
}
static bool isNonZero(const Token* tok)
{
return tok && (!tok->hasKnownIntValue() || tok->values().front().intvalue != 0);
}
static const Token* getOtherOperand(const Token* tok)
{
if (!tok)
return nullptr;
if (!tok->astParent())
return nullptr;
if (tok->astParent()->astOperand1() != tok)
return tok->astParent()->astOperand1();
if (tok->astParent()->astOperand2() != tok)
return tok->astParent()->astOperand2();
return nullptr;
}
static void valueFlowArrayBool(TokenList& tokenlist, const Settings& settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
const Variable* var = nullptr;
bool known = false;
const auto val =
std::find_if(tok->values().cbegin(), tok->values().cend(), std::mem_fn(&ValueFlow::Value::isTokValue));
if (val == tok->values().end()) {
var = tok->variable();
known = true;
} else {
var = val->tokvalue->variable();
known = val->isKnown();
}
if (!var)
continue;
if (!var->isArray() || var->isArgument() || var->isStlType())
continue;
if (isNonZero(getOtherOperand(tok)) && Token::Match(tok->astParent(), "%comp%"))
continue;
// TODO: Check for function argument
if ((astIsBool(tok->astParent()) && !Token::Match(tok->astParent(), "(|%name%")) ||
(tok->astParent() && Token::Match(tok->astParent()->previous(), "if|while|for ("))) {
ValueFlow::Value value{1};
if (known)
value.setKnown();
setTokenValue(tok, std::move(value), settings);
}
}
}
static void valueFlowArrayElement(TokenList& tokenlist, const Settings& settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
const Token* indexTok = nullptr;
const Token* arrayTok = nullptr;
if (Token::simpleMatch(tok, "[") && tok->isBinaryOp()) {
indexTok = tok->astOperand2();
arrayTok = tok->astOperand1();
} else if (Token::Match(tok->tokAt(-2), ". %name% (") && astIsContainer(tok->tokAt(-2)->astOperand1())) {
arrayTok = tok->tokAt(-2)->astOperand1();
const Library::Container* container = getLibraryContainer(arrayTok);
if (!container || container->stdAssociativeLike)
continue;
const Library::Container::Yield yield = container->getYield(tok->strAt(-1));
if (yield != Library::Container::Yield::AT_INDEX)
continue;
indexTok = tok->astOperand2();
}
if (!indexTok || !arrayTok)
continue;
for (const ValueFlow::Value& arrayValue : arrayTok->values()) {
if (!arrayValue.isTokValue())
continue;
if (arrayValue.isImpossible())
continue;
for (const ValueFlow::Value& indexValue : indexTok->values()) {
if (!indexValue.isIntValue())
continue;
if (indexValue.isImpossible())
continue;
if (!arrayValue.isKnown() && !indexValue.isKnown() && arrayValue.varId != 0 && indexValue.varId != 0 &&
!(arrayValue.varId == indexValue.varId && arrayValue.varvalue == indexValue.varvalue))
continue;
ValueFlow::Value result(0);
result.condition = arrayValue.condition ? arrayValue.condition : indexValue.condition;
result.setInconclusive(arrayValue.isInconclusive() || indexValue.isInconclusive());
result.varId = (arrayValue.varId != 0) ? arrayValue.varId : indexValue.varId;
result.varvalue = (result.varId == arrayValue.varId) ? arrayValue.intvalue : indexValue.intvalue;
if (arrayValue.valueKind == indexValue.valueKind)
result.valueKind = arrayValue.valueKind;
result.errorPath.insert(result.errorPath.end(),
arrayValue.errorPath.cbegin(),
arrayValue.errorPath.cend());
result.errorPath.insert(result.errorPath.end(),
indexValue.errorPath.cbegin(),
indexValue.errorPath.cend());
const MathLib::bigint index = indexValue.intvalue;
if (arrayValue.tokvalue->tokType() == Token::eString) {
const std::string s = arrayValue.tokvalue->strValue();
if (index == s.size()) {
result.intvalue = 0;
setTokenValue(tok, std::move(result), settings);
} else if (index >= 0 && index < s.size()) {
result.intvalue = s[static_cast<std::size_t>(index)];
setTokenValue(tok, std::move(result), settings);
}
} else if (Token::simpleMatch(arrayValue.tokvalue, "{")) {
std::vector<const Token*> args = getArguments(arrayValue.tokvalue);
if (index < 0 || index >= args.size())
continue;
const Token* arg = args[static_cast<std::size_t>(index)];
if (!arg->hasKnownIntValue())
continue;
const ValueFlow::Value& v = arg->values().front();
result.intvalue = v.intvalue;
result.errorPath.insert(result.errorPath.end(), v.errorPath.cbegin(), v.errorPath.cend());
setTokenValue(tok, std::move(result), settings);
}
}
}
}
}
static void valueFlowPointerAlias(TokenList& tokenlist, const Settings& settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
// not address of
if (!tok->isUnaryOp("&"))
continue;
// parent should be a '='
if (!Token::simpleMatch(tok->astParent(), "="))
continue;
// child should be some buffer or variable
const Token* vartok = tok->astOperand1();
while (vartok) {
if (vartok->str() == "[")
vartok = vartok->astOperand1();
else if (vartok->str() == "." || vartok->str() == "::")
vartok = vartok->astOperand2();
else
break;
}
if (!(vartok && vartok->variable() && !vartok->variable()->isPointer()))
continue;
ValueFlow::Value value;
value.valueType = ValueFlow::Value::ValueType::TOK;
value.tokvalue = tok;
setTokenValue(tok, std::move(value), settings);
}
}
static void valueFlowBitAnd(TokenList& tokenlist, const Settings& settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->str() != "&")
continue;
if (tok->hasKnownValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
MathLib::bigint number;
if (MathLib::isInt(tok->astOperand1()->str()))
number = MathLib::toBigNumber(tok->astOperand1());
else if (MathLib::isInt(tok->astOperand2()->str()))
number = MathLib::toBigNumber(tok->astOperand2());
else
continue;
int bit = 0;
while (bit <= (MathLib::bigint_bits - 2) && ((((MathLib::bigint)1) << bit) < number))
++bit;
if ((((MathLib::bigint)1) << bit) == number) {
setTokenValue(tok, ValueFlow::Value(0), settings);
setTokenValue(tok, ValueFlow::Value(number), settings);
}
}
}
static void valueFlowSameExpressions(TokenList& tokenlist, const Settings& settings)
{
for (Token* tok = tokenlist.front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
if (tok->astOperand1()->isLiteral() || tok->astOperand2()->isLiteral())
continue;
if (!astIsIntegral(tok->astOperand1(), false) && !astIsIntegral(tok->astOperand2(), false))
continue;
long long val;
if (Token::Match(tok, "==|>=|<=|/")) {
val = 1;
}
else if (Token::Match(tok, "!=|>|<|%|-")) {
val = 0;
}
else
continue;
ValueFlow::Value value(val);
value.setKnown();
if (isSameExpression(false, tok->astOperand1(), tok->astOperand2(), settings, true, true, &value.errorPath)) {
setTokenValue(tok, std::move(value), settings);
}
}
}
static bool getExpressionRange(const Token* expr, MathLib::bigint* minvalue, MathLib::bigint* maxvalue)
{
if (expr->hasKnownIntValue()) {
if (minvalue)
*minvalue = expr->values().front().intvalue;
if (maxvalue)
*maxvalue = expr->values().front().intvalue;
return true;
}
if (expr->str() == "&" && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint vals[4];
const bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
const bool rhsHasKnownRange = getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]);
if (!lhsHasKnownRange && !rhsHasKnownRange)
return false;
if (!lhsHasKnownRange || !rhsHasKnownRange) {
if (minvalue)
*minvalue = lhsHasKnownRange ? vals[0] : vals[2];
if (maxvalue)
*maxvalue = lhsHasKnownRange ? vals[1] : vals[3];
} else {
if (minvalue)
*minvalue = vals[0] & vals[2];
if (maxvalue)
*maxvalue = vals[1] & vals[3];
}
return true;
}
if (expr->str() == "%" && expr->astOperand1() && expr->astOperand2()) {
MathLib::bigint vals[4];
if (!getExpressionRange(expr->astOperand2(), &vals[2], &vals[3]))
return false;
if (vals[2] <= 0)
return false;
const bool lhsHasKnownRange = getExpressionRange(expr->astOperand1(), &vals[0], &vals[1]);
if (lhsHasKnownRange && vals[0] < 0)
return false;
// If lhs has unknown value, it must be unsigned
if (!lhsHasKnownRange &&
(!expr->astOperand1()->valueType() || expr->astOperand1()->valueType()->sign != ValueType::Sign::UNSIGNED))
return false;
if (minvalue)
*minvalue = 0;
if (maxvalue)
*maxvalue = vals[3] - 1;
return true;
}
return false;
}
static void valueFlowRightShift(TokenList& tokenList, const Settings& settings)
{
for (Token* tok = tokenList.front(); tok; tok = tok->next()) {
if (tok->str() != ">>")
continue;
if (tok->hasKnownValue())
continue;
if (!tok->astOperand1() || !tok->astOperand2())
continue;
if (!tok->astOperand2()->hasKnownValue())
continue;
const MathLib::bigint rhsvalue = tok->astOperand2()->values().front().intvalue;
if (rhsvalue < 0)
continue;
if (!tok->astOperand1()->valueType() || !tok->astOperand1()->valueType()->isIntegral())
continue;
if (!tok->astOperand2()->valueType() || !tok->astOperand2()->valueType()->isIntegral())
continue;
MathLib::bigint lhsmax = 0;
if (!getExpressionRange(tok->astOperand1(), nullptr, &lhsmax))
continue;
if (lhsmax < 0)
continue;
int lhsbits;
if ((tok->astOperand1()->valueType()->type == ValueType::Type::CHAR) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::SHORT) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::WCHAR_T) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::BOOL) ||
(tok->astOperand1()->valueType()->type == ValueType::Type::INT))
lhsbits = settings.platform.int_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONG)
lhsbits = settings.platform.long_bit;
else if (tok->astOperand1()->valueType()->type == ValueType::Type::LONGLONG)
lhsbits = settings.platform.long_long_bit;
else
continue;
if (rhsvalue >= lhsbits || rhsvalue >= MathLib::bigint_bits || (1ULL << rhsvalue) <= lhsmax)
continue;
ValueFlow::Value val(0);
val.setKnown();
setTokenValue(tok, std::move(val), settings);
}
}
static std::vector<MathLib::bigint> minUnsignedValue(const Token* tok, int depth = 8)
{
std::vector<MathLib::bigint> result;
if (!tok)
return result;
if (depth < 0)
return result;
if (tok->hasKnownIntValue()) {
result = {tok->values().front().intvalue};
} else if (!Token::Match(tok, "-|%|&|^") && tok->isConstOp() && tok->astOperand1() && tok->astOperand2()) {
std::vector<MathLib::bigint> op1 = minUnsignedValue(tok->astOperand1(), depth - 1);
if (!op1.empty()) {
std::vector<MathLib::bigint> op2 = minUnsignedValue(tok->astOperand2(), depth - 1);
if (!op2.empty()) {
result = calculate<std::vector<MathLib::bigint>>(tok->str(), op1.front(), op2.front());
}
}