walkero
/
cppcheck
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

ExprEngine: Value truncation

This commit is contained in:
Daniel Marjamäki 2019-09-23 20:27:13 +02:00
parent 1616282f6b
commit c1ff3419a6
3 changed files with 112 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

108
lib/exprengine.cpp
View File

@ -335,6 +335,11 @@ void ExprEngine::BinOpResult::getRange(ExprEngine::BinOpResult::IntOrFloatValue
}
}
std::string ExprEngine::IntegerTruncation::getRange() const
{
return sign + std::to_string(bits) + "(" + inputValue->getRange() + ")";
}
bool ExprEngine::BinOpResult::isIntValueInRange(int value) const
{
IntOrFloatValue minValue, maxValue;
@ -419,31 +424,46 @@ ExprEngine::BinOpResult::IntOrFloatValue ExprEngine::BinOpResult::evaluateOperan
}
// Todo: This is taken from ValueFlow and modified.. we should reuse it
static int getIntBitsFromValueType(const ValueType *vt, const cppcheck::Platform &platform)
{
if (!vt)
return 0;
switch (vt->type) {
case ValueType::Type::BOOL:
return 1;
case ValueType::Type::CHAR:
return platform.char_bit;
case ValueType::Type::SHORT:
return platform.short_bit;
case ValueType::Type::INT:
return platform.int_bit;
case ValueType::Type::LONG:
return platform.long_bit;
case ValueType::Type::LONGLONG:
return platform.long_long_bit;
default:
return 0;
};
}
static ExprEngine::ValuePtr getValueRangeFromValueType(const std::string &name, const ValueType *vt, const cppcheck::Platform &platform)
{
if (!vt || !(vt->isIntegral() || vt->isFloat()) || vt->pointer)
return ExprEngine::ValuePtr();
int bits;
int bits = getIntBitsFromValueType(vt, platform);
if (bits == 1) {
return std::make_shared<ExprEngine::IntRange>(name, 0, 1);
} else if (bits > 1) {
if (vt->sign == ValueType::Sign::UNSIGNED) {
return std::make_shared<ExprEngine::IntRange>(name, 0, ((int128_t)1 << bits) - 1);
} else {
return std::make_shared<ExprEngine::IntRange>(name, -((int128_t)1 << (bits - 1)), ((int128_t)1 << (bits - 1)) - 1);
}
}
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;
case ValueType::Type::FLOAT:
return std::make_shared<ExprEngine::FloatRange>(name, std::numeric_limits<float>::min(), std::numeric_limits<float>::max());
case ValueType::Type::DOUBLE:
@ -453,18 +473,6 @@ static ExprEngine::ValuePtr getValueRangeFromValueType(const std::string &name,
default:
return ExprEngine::ValuePtr();
};
if (bits == 1) {
return std::make_shared<ExprEngine::IntRange>(name, 0, 1);
} else {
if (vt->sign == ValueType::Sign::UNSIGNED) {
return std::make_shared<ExprEngine::IntRange>(name, 0, ((int128_t)1 << bits) - 1);
} else {
return std::make_shared<ExprEngine::IntRange>(name, -((int128_t)1 << (bits - 1)), ((int128_t)1 << (bits - 1)) - 1);
}
}
return ExprEngine::ValuePtr();
}
static void call(const std::vector<ExprEngine::Callback> &callbacks, const Token *tok, ExprEngine::ValuePtr value)
@ -485,6 +493,42 @@ static ExprEngine::ValuePtr executeReturn(const Token *tok, Data &data)
return retval;
}
static ExprEngine::ValuePtr truncateValue(ExprEngine::ValuePtr val, const ValueType *valueType, Data &data)
{
if (valueType->pointer != 0)
return val;
if (!valueType->isIntegral())
return val; // TODO
int bits = getIntBitsFromValueType(valueType, *data.settings);
if (bits == 0)
// TODO
return val;
if (auto range = std::dynamic_pointer_cast<ExprEngine::IntRange>(val)) {
if (range->minValue == range->maxValue) {
int128_t newValue = range->minValue;
newValue = newValue & (((int128_t)1 << bits) - 1);
// TODO: Sign extension
if (newValue == range->minValue)
return val;
return std::make_shared<ExprEngine::IntRange>(ExprEngine::str(newValue), newValue, newValue);
}
if (auto typeRange = getValueRangeFromValueType("", valueType, *data.settings)) {
auto typeIntRange = std::dynamic_pointer_cast<ExprEngine::IntRange>(typeRange);
if (typeIntRange) {
if (range->minValue >= typeIntRange->minValue && range->maxValue <= typeIntRange->maxValue)
return val;
}
}
return std::make_shared<ExprEngine::IntegerTruncation>(data.getNewSymbolName(), val, bits, valueType->sign == ValueType::Sign::SIGNED ? 's' : 'u');
}
// TODO
return val;
}
static ExprEngine::ValuePtr executeAssign(const Token *tok, Data &data)
{
ExprEngine::ValuePtr rhsValue = executeExpression(tok->astOperand2(), data);
@ -503,7 +547,7 @@ static ExprEngine::ValuePtr executeAssign(const Token *tok, Data &data)
const Token *lhsToken = tok->astOperand1();
data.trackAssignment(lhsToken, rhsValue);
if (lhsToken->varId() > 0) {
data.memory[lhsToken->varId()] = rhsValue;
data.memory[lhsToken->varId()] = truncateValue(rhsValue, lhsToken->valueType(), data);
} else if (lhsToken->str() == "[") {
auto arrayValue = data.getArrayValue(lhsToken->astOperand1());
if (arrayValue) {

32
lib/exprengine.h
View File

@ -52,7 +52,18 @@ namespace ExprEngine {
std::string str(int128_t);
// TODO we need to handle floats, containers, pointers, aliases and structs and stuff
enum class ValueType { UninitValue, IntRange, FloatRange, PointerValue, ArrayValue, StringLiteralValue, StructValue, AddressOfValue, BinOpResult };
enum class ValueType {
UninitValue,
IntRange,
FloatRange,
PointerValue,
ArrayValue,
StringLiteralValue,
StructValue,
AddressOfValue,
BinOpResult,
IntegerTruncation
};
class Value;
typedef std::shared_ptr<Value> ValuePtr;
@ -274,6 +285,25 @@ namespace ExprEngine {
std::set<ValuePtr> mLeafs;
};
class IntegerTruncation : public Value {
public:
IntegerTruncation(const std::string &name, ValuePtr inputValue, int bits, char sign)
: Value(name)
, inputValue(inputValue)
, bits(bits)
, sign(sign) {
}
ValueType type() const override {
return ValueType::IntegerTruncation;
}
std::string getRange() const override;
ExprEngine::ValuePtr inputValue;
int bits;
char sign;
};
typedef std::function<void(const Token *, const ExprEngine::Value &)> Callback;
/** Execute all functions */

5
test/testexprengine.cpp
View File

@ -42,6 +42,7 @@ private:
TEST_CASE(expr4);
TEST_CASE(expr5);
TEST_CASE(exprAssign1);
TEST_CASE(exprAssign2); // Truncation
TEST_CASE(floatValue1);
TEST_CASE(floatValue2);
@ -131,6 +132,10 @@ private:
ASSERT_EQUALS("1:256", getRange("void f(unsigned char a) { a += 1; }", "a+=1"));
}
void exprAssign2() {
ASSERT_EQUALS("2", getRange("void f(unsigned char x) { x = 258; int a = x }", "a=x"));
}
void floatValue1() {
ASSERT_EQUALS(std::to_string(std::numeric_limits<float>::min()) + ":" + std::to_string(std::numeric_limits<float>::max()), getRange("float f; void func() { f=f; }", "f=f"));
}