mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
[SMTChecker] Only check for overflow/underflow in the end of the function
This commit is contained in:
parent
2949bd14dd
commit
34470f3549
@ -4,6 +4,7 @@ Language Features:
|
|||||||
|
|
||||||
|
|
||||||
Compiler Features:
|
Compiler Features:
|
||||||
|
* SMTChecker: Do not report underflow/overflow if they always revert. This removes false positives when using ``SafeMath``.
|
||||||
* Static Analyzer: Warn about expressions with custom types when they have no effect.
|
* Static Analyzer: Warn about expressions with custom types when they have no effect.
|
||||||
|
|
||||||
|
|
||||||
|
@ -21,7 +21,6 @@
|
|||||||
#include <libsolidity/formal/VariableUsage.h>
|
#include <libsolidity/formal/VariableUsage.h>
|
||||||
#include <libsolidity/formal/SymbolicTypes.h>
|
#include <libsolidity/formal/SymbolicTypes.h>
|
||||||
|
|
||||||
#include <liblangutil/ErrorReporter.h>
|
|
||||||
#include <libdevcore/StringUtils.h>
|
#include <libdevcore/StringUtils.h>
|
||||||
|
|
||||||
#include <boost/range/adaptor/map.hpp>
|
#include <boost/range/adaptor/map.hpp>
|
||||||
@ -109,6 +108,7 @@ bool SMTChecker::visit(FunctionDefinition const& _function)
|
|||||||
m_expressions.clear();
|
m_expressions.clear();
|
||||||
m_globalContext.clear();
|
m_globalContext.clear();
|
||||||
m_uninterpretedTerms.clear();
|
m_uninterpretedTerms.clear();
|
||||||
|
m_overflowTargets.clear();
|
||||||
resetStateVariables();
|
resetStateVariables();
|
||||||
initializeLocalVariables(_function);
|
initializeLocalVariables(_function);
|
||||||
m_loopExecutionHappened = false;
|
m_loopExecutionHappened = false;
|
||||||
@ -126,7 +126,10 @@ void SMTChecker::endVisit(FunctionDefinition const&)
|
|||||||
// Otherwise we remove any local variables from the context and
|
// Otherwise we remove any local variables from the context and
|
||||||
// keep the state variables.
|
// keep the state variables.
|
||||||
if (isRootFunction())
|
if (isRootFunction())
|
||||||
|
{
|
||||||
|
checkUnderOverflow();
|
||||||
removeLocalVariables();
|
removeLocalVariables();
|
||||||
|
}
|
||||||
m_functionPath.pop_back();
|
m_functionPath.pop_back();
|
||||||
}
|
}
|
||||||
|
|
||||||
@ -316,21 +319,56 @@ void SMTChecker::endVisit(TupleExpression const& _tuple)
|
|||||||
defineExpr(_tuple, expr(*_tuple.components()[0]));
|
defineExpr(_tuple, expr(*_tuple.components()[0]));
|
||||||
}
|
}
|
||||||
|
|
||||||
void SMTChecker::checkUnderOverflow(smt::Expression _value, IntegerType const& _type, SourceLocation const& _location)
|
void SMTChecker::addOverflowTarget(
|
||||||
|
OverflowTarget::Type _type,
|
||||||
|
TypePointer _intType,
|
||||||
|
smt::Expression _value,
|
||||||
|
SourceLocation const& _location
|
||||||
|
)
|
||||||
{
|
{
|
||||||
checkCondition(
|
m_overflowTargets.emplace_back(
|
||||||
_value < minValue(_type),
|
_type,
|
||||||
_location,
|
std::move(_intType),
|
||||||
"Underflow (resulting value less than " + formatNumberReadable(_type.minValue()) + ")",
|
std::move(_value),
|
||||||
"<result>",
|
currentPathConditions(),
|
||||||
&_value
|
_location
|
||||||
);
|
);
|
||||||
|
}
|
||||||
|
|
||||||
|
void SMTChecker::checkUnderOverflow()
|
||||||
|
{
|
||||||
|
for (auto& target: m_overflowTargets)
|
||||||
|
{
|
||||||
|
if (target.type != OverflowTarget::Type::Overflow)
|
||||||
|
checkUnderflow(target);
|
||||||
|
if (target.type != OverflowTarget::Type::Underflow)
|
||||||
|
checkOverflow(target);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
void SMTChecker::checkUnderflow(OverflowTarget& _target)
|
||||||
|
{
|
||||||
|
solAssert(_target.type != OverflowTarget::Type::Overflow, "");
|
||||||
|
auto intType = dynamic_cast<IntegerType const*>(_target.intType.get());
|
||||||
checkCondition(
|
checkCondition(
|
||||||
_value > maxValue(_type),
|
_target.path && _target.value < minValue(*intType),
|
||||||
_location,
|
_target.location,
|
||||||
"Overflow (resulting value larger than " + formatNumberReadable(_type.maxValue()) + ")",
|
"Underflow (resulting value less than " + formatNumberReadable(intType->minValue()) + ")",
|
||||||
"<result>",
|
"<result>",
|
||||||
&_value
|
&_target.value
|
||||||
|
);
|
||||||
|
}
|
||||||
|
|
||||||
|
void SMTChecker::checkOverflow(OverflowTarget& _target)
|
||||||
|
{
|
||||||
|
solAssert(_target.type != OverflowTarget::Type::Underflow, "");
|
||||||
|
auto intType = dynamic_cast<IntegerType const*>(_target.intType.get());
|
||||||
|
checkCondition(
|
||||||
|
_target.path && _target.value > maxValue(*intType),
|
||||||
|
_target.location,
|
||||||
|
"Overflow (resulting value larger than " + formatNumberReadable(intType->maxValue()) + ")",
|
||||||
|
"<result>",
|
||||||
|
&_target.value
|
||||||
);
|
);
|
||||||
}
|
}
|
||||||
|
|
||||||
@ -376,8 +414,13 @@ void SMTChecker::endVisit(UnaryOperation const& _op)
|
|||||||
case Token::Sub: // -
|
case Token::Sub: // -
|
||||||
{
|
{
|
||||||
defineExpr(_op, 0 - expr(_op.subExpression()));
|
defineExpr(_op, 0 - expr(_op.subExpression()));
|
||||||
if (auto intType = dynamic_cast<IntegerType const*>(_op.annotation().type.get()))
|
if (dynamic_cast<IntegerType const*>(_op.annotation().type.get()))
|
||||||
checkUnderOverflow(expr(_op), *intType, _op.location());
|
addOverflowTarget(
|
||||||
|
OverflowTarget::Type::All,
|
||||||
|
_op.annotation().type,
|
||||||
|
expr(_op),
|
||||||
|
_op.location()
|
||||||
|
);
|
||||||
break;
|
break;
|
||||||
}
|
}
|
||||||
default:
|
default:
|
||||||
@ -853,9 +896,28 @@ void SMTChecker::arithmeticOperation(BinaryOperation const& _op)
|
|||||||
m_interface->addAssertion(right != 0);
|
m_interface->addAssertion(right != 0);
|
||||||
}
|
}
|
||||||
|
|
||||||
checkUnderOverflow(value, intType, _op.location());
|
addOverflowTarget(
|
||||||
|
OverflowTarget::Type::All,
|
||||||
|
_op.annotation().commonType,
|
||||||
|
value,
|
||||||
|
_op.location()
|
||||||
|
);
|
||||||
|
|
||||||
|
smt::Expression intValueRange = (0 - minValue(intType)) + maxValue(intType) + 1;
|
||||||
|
defineExpr(_op, smt::Expression::ite(
|
||||||
|
value > maxValue(intType) || value < minValue(intType),
|
||||||
|
value % intValueRange,
|
||||||
|
value
|
||||||
|
));
|
||||||
|
if (intType.isSigned())
|
||||||
|
{
|
||||||
|
defineExpr(_op, smt::Expression::ite(
|
||||||
|
expr(_op) > maxValue(intType),
|
||||||
|
expr(_op) - intValueRange,
|
||||||
|
expr(_op)
|
||||||
|
));
|
||||||
|
}
|
||||||
|
|
||||||
defineExpr(_op, value);
|
|
||||||
break;
|
break;
|
||||||
}
|
}
|
||||||
default:
|
default:
|
||||||
@ -944,10 +1006,10 @@ void SMTChecker::assignment(VariableDeclaration const& _variable, Expression con
|
|||||||
void SMTChecker::assignment(VariableDeclaration const& _variable, smt::Expression const& _value, SourceLocation const& _location)
|
void SMTChecker::assignment(VariableDeclaration const& _variable, smt::Expression const& _value, SourceLocation const& _location)
|
||||||
{
|
{
|
||||||
TypePointer type = _variable.type();
|
TypePointer type = _variable.type();
|
||||||
if (auto const* intType = dynamic_cast<IntegerType const*>(type.get()))
|
if (dynamic_cast<IntegerType const*>(type.get()))
|
||||||
checkUnderOverflow(_value, *intType, _location);
|
addOverflowTarget(OverflowTarget::Type::All, type, _value, _location);
|
||||||
else if (dynamic_cast<AddressType const*>(type.get()))
|
else if (dynamic_cast<AddressType const*>(type.get()))
|
||||||
checkUnderOverflow(_value, IntegerType(160), _location);
|
addOverflowTarget(OverflowTarget::Type::All, make_shared<IntegerType>(160), _value, _location);
|
||||||
else if (dynamic_cast<MappingType const*>(type.get()))
|
else if (dynamic_cast<MappingType const*>(type.get()))
|
||||||
arrayAssignment();
|
arrayAssignment();
|
||||||
m_interface->addAssertion(newValue(_variable) == _value);
|
m_interface->addAssertion(newValue(_variable) == _value);
|
||||||
|
@ -137,9 +137,33 @@ private:
|
|||||||
Expression const& _condition,
|
Expression const& _condition,
|
||||||
std::string const& _description
|
std::string const& _description
|
||||||
);
|
);
|
||||||
/// Checks that the value is in the range given by the type.
|
|
||||||
void checkUnderOverflow(smt::Expression _value, IntegerType const& _Type, langutil::SourceLocation const& _location);
|
|
||||||
|
|
||||||
|
struct OverflowTarget
|
||||||
|
{
|
||||||
|
enum class Type { Underflow, Overflow, All } type;
|
||||||
|
TypePointer intType;
|
||||||
|
smt::Expression value;
|
||||||
|
smt::Expression path;
|
||||||
|
langutil::SourceLocation const& location;
|
||||||
|
|
||||||
|
OverflowTarget(Type _type, TypePointer _intType, smt::Expression _value, smt::Expression _path, langutil::SourceLocation const& _location):
|
||||||
|
type(_type),
|
||||||
|
intType(_intType),
|
||||||
|
value(_value),
|
||||||
|
path(_path),
|
||||||
|
location(_location)
|
||||||
|
{
|
||||||
|
solAssert(dynamic_cast<IntegerType const*>(intType.get()), "");
|
||||||
|
}
|
||||||
|
};
|
||||||
|
|
||||||
|
/// Checks that the value is in the range given by the type.
|
||||||
|
void checkUnderflow(OverflowTarget& _target);
|
||||||
|
void checkOverflow(OverflowTarget& _target);
|
||||||
|
/// Calls the functions above for all elements in m_overflowTargets accordingly.
|
||||||
|
void checkUnderOverflow();
|
||||||
|
/// Adds an overflow target for lazy check at the end of the function.
|
||||||
|
void addOverflowTarget(OverflowTarget::Type _type, TypePointer _intType, smt::Expression _value, langutil::SourceLocation const& _location);
|
||||||
|
|
||||||
std::pair<smt::CheckResult, std::vector<std::string>>
|
std::pair<smt::CheckResult, std::vector<std::string>>
|
||||||
checkSatisfiableAndGenerateModel(std::vector<smt::Expression> const& _expressionsToEvaluate);
|
checkSatisfiableAndGenerateModel(std::vector<smt::Expression> const& _expressionsToEvaluate);
|
||||||
@ -244,6 +268,8 @@ private:
|
|||||||
bool isRootFunction();
|
bool isRootFunction();
|
||||||
/// Returns true if _funDef was already visited.
|
/// Returns true if _funDef was already visited.
|
||||||
bool visitedFunction(FunctionDefinition const* _funDef);
|
bool visitedFunction(FunctionDefinition const* _funDef);
|
||||||
|
|
||||||
|
std::vector<OverflowTarget> m_overflowTargets;
|
||||||
};
|
};
|
||||||
|
|
||||||
}
|
}
|
||||||
|
@ -12,6 +12,5 @@ contract C
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (150-155): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (146-155): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (179-193): Assertion violation happens here
|
// Warning: (179-193): Assertion violation happens here
|
||||||
|
// Warning: (150-155): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -14,6 +14,5 @@ contract C
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (150-155): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (146-155): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (269-282): Assertion violation happens here
|
// Warning: (269-282): Assertion violation happens here
|
||||||
|
// Warning: (150-155): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -12,6 +12,9 @@ contract C
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (176-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (172-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (189-203): Assertion violation happens here
|
// Warning: (189-203): Assertion violation happens here
|
||||||
|
// Warning: (176-181): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (176-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
// Warning: (172-181): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (172-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
// Warning: (126-129): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -13,6 +13,9 @@ contract C
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (176-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (172-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
|
||||||
// Warning: (244-257): Assertion violation happens here
|
// Warning: (244-257): Assertion violation happens here
|
||||||
|
// Warning: (176-181): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (176-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
// Warning: (172-181): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (172-181): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
// Warning: (126-129): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -8,3 +8,5 @@ contract C {
|
|||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (136-150): Assertion violation happens here
|
// Warning: (136-150): Assertion violation happens here
|
||||||
|
// Warning: (115-120): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (115-120): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -10,3 +10,5 @@ contract C {
|
|||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (167-181): Assertion violation happens here
|
// Warning: (167-181): Assertion violation happens here
|
||||||
|
// Warning: (142-147): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (142-147): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -11,3 +11,5 @@ contract C {
|
|||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (213-226): Assertion violation happens here
|
// Warning: (213-226): Assertion violation happens here
|
||||||
|
// Warning: (142-147): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (142-147): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -11,3 +11,5 @@ contract C {
|
|||||||
}
|
}
|
||||||
// ----
|
// ----
|
||||||
// Warning: (138-144): For loop condition is always true.
|
// Warning: (138-144): For loop condition is always true.
|
||||||
|
// Warning: (161-166): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (161-166): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
@ -16,3 +16,5 @@ contract C {
|
|||||||
// ----
|
// ----
|
||||||
// Warning: (115-121): Unused local variable.
|
// Warning: (115-121): Unused local variable.
|
||||||
// Warning: (356-370): Assertion violation happens here
|
// Warning: (356-370): Assertion violation happens here
|
||||||
|
// Warning: (285-290): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (285-290): Overflow (resulting value larger than 2**256 - 1) happens here
|
||||||
|
17
test/libsolidity/smtCheckerTests/overflow/overflow_mul.sol
Normal file
17
test/libsolidity/smtCheckerTests/overflow/overflow_mul.sol
Normal file
@ -0,0 +1,17 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function f(uint8 x) public pure returns (uint8) {
|
||||||
|
x = 100;
|
||||||
|
uint8 y = x * 3;
|
||||||
|
assert(y == 44);
|
||||||
|
x = 128;
|
||||||
|
y = x * 4;
|
||||||
|
assert(y == 0);
|
||||||
|
return y;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (120-125): Overflow (resulting value larger than 255) happens here
|
||||||
|
// Warning: (163-168): Overflow (resulting value larger than 255) happens here
|
@ -0,0 +1,16 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function f(int8 x) public pure returns (int8) {
|
||||||
|
x = 100;
|
||||||
|
int8 y = x * 2;
|
||||||
|
assert(y == -56);
|
||||||
|
y = x * 100;
|
||||||
|
assert(y == 16);
|
||||||
|
return y;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (117-122): Overflow (resulting value larger than 127) happens here
|
||||||
|
// Warning: (150-157): Overflow (resulting value larger than 127) happens here
|
18
test/libsolidity/smtCheckerTests/overflow/overflow_sum.sol
Normal file
18
test/libsolidity/smtCheckerTests/overflow/overflow_sum.sol
Normal file
@ -0,0 +1,18 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function f(uint8 x) public pure returns (uint8) {
|
||||||
|
uint8 y = x + 255;
|
||||||
|
require(y >= x);
|
||||||
|
x = 255;
|
||||||
|
y = x + 1;
|
||||||
|
assert(y == 0);
|
||||||
|
y = x + 255;
|
||||||
|
assert(y == 254);
|
||||||
|
return y;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (154-159): Overflow (resulting value larger than 255) happens here
|
||||||
|
// Warning: (185-192): Overflow (resulting value larger than 255) happens here
|
@ -0,0 +1,19 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function f(int8 x) public pure returns (int8) {
|
||||||
|
x = 127;
|
||||||
|
int8 y = x + 1;
|
||||||
|
assert(y == -128);
|
||||||
|
y = x + 127;
|
||||||
|
assert(y == -2);
|
||||||
|
x = -127;
|
||||||
|
y = x + -127;
|
||||||
|
assert(y == 2);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (117-122): Overflow (resulting value larger than 127) happens here
|
||||||
|
// Warning: (151-158): Overflow (resulting value larger than 127) happens here
|
||||||
|
// Warning: (197-205): Underflow (resulting value less than -128) happens here
|
9
test/libsolidity/smtCheckerTests/overflow/safe_add_1.sol
Normal file
9
test/libsolidity/smtCheckerTests/overflow/safe_add_1.sol
Normal file
@ -0,0 +1,9 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function add(uint x, uint y) public pure returns (uint) {
|
||||||
|
require(x + y >= x);
|
||||||
|
return x + y;
|
||||||
|
}
|
||||||
|
}
|
10
test/libsolidity/smtCheckerTests/overflow/safe_add_2.sol
Normal file
10
test/libsolidity/smtCheckerTests/overflow/safe_add_2.sol
Normal file
@ -0,0 +1,10 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function add(uint x, uint y) public pure returns (uint) {
|
||||||
|
uint z = x + y;
|
||||||
|
require(z >= x);
|
||||||
|
return z;
|
||||||
|
}
|
||||||
|
}
|
10
test/libsolidity/smtCheckerTests/overflow/safe_div_1.sol
Normal file
10
test/libsolidity/smtCheckerTests/overflow/safe_div_1.sol
Normal file
@ -0,0 +1,10 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function div(uint256 a, uint256 b) internal pure returns (uint256) {
|
||||||
|
require(b > 0);
|
||||||
|
uint256 c = a / b;
|
||||||
|
return c;
|
||||||
|
}
|
||||||
|
}
|
13
test/libsolidity/smtCheckerTests/overflow/safe_mul_1.sol
Normal file
13
test/libsolidity/smtCheckerTests/overflow/safe_mul_1.sol
Normal file
@ -0,0 +1,13 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
|
||||||
|
uint256 c;
|
||||||
|
if (a != 0) {
|
||||||
|
c = a * b;
|
||||||
|
require(c / a == b);
|
||||||
|
}
|
||||||
|
return c;
|
||||||
|
}
|
||||||
|
}
|
15
test/libsolidity/smtCheckerTests/overflow/safe_mul_2.sol
Normal file
15
test/libsolidity/smtCheckerTests/overflow/safe_mul_2.sol
Normal file
@ -0,0 +1,15 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
|
||||||
|
if (a == 0) {
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
uint256 c = a * b;
|
||||||
|
require(c / a == b);
|
||||||
|
return c;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (180-185): Division by zero happens here
|
10
test/libsolidity/smtCheckerTests/overflow/safe_sub_1.sol
Normal file
10
test/libsolidity/smtCheckerTests/overflow/safe_sub_1.sol
Normal file
@ -0,0 +1,10 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
|
||||||
|
require(b <= a);
|
||||||
|
uint256 c = a - b;
|
||||||
|
return c;
|
||||||
|
}
|
||||||
|
}
|
16
test/libsolidity/smtCheckerTests/overflow/underflow_sub.sol
Normal file
16
test/libsolidity/smtCheckerTests/overflow/underflow_sub.sol
Normal file
@ -0,0 +1,16 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function f(uint8 x) public pure returns (uint) {
|
||||||
|
x = 0;
|
||||||
|
uint8 y = x - 1;
|
||||||
|
assert(y == 255);
|
||||||
|
y = x - 255;
|
||||||
|
assert(y == 1);
|
||||||
|
return y;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (117-122): Underflow (resulting value less than 0) happens here
|
||||||
|
// Warning: (150-157): Underflow (resulting value less than 0) happens here
|
@ -0,0 +1,21 @@
|
|||||||
|
pragma experimental SMTChecker;
|
||||||
|
|
||||||
|
contract C
|
||||||
|
{
|
||||||
|
function f(int8 x) public pure returns (int8) {
|
||||||
|
x = -2;
|
||||||
|
int8 y = x - 127;
|
||||||
|
assert(y == 127);
|
||||||
|
x = -128;
|
||||||
|
y = x - 127;
|
||||||
|
assert(y == 1);
|
||||||
|
x = 127;
|
||||||
|
y = x - (-127);
|
||||||
|
assert(y == -2);
|
||||||
|
return y;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// ----
|
||||||
|
// Warning: (116-123): Underflow (resulting value less than -128) happens here
|
||||||
|
// Warning: (163-170): Underflow (resulting value less than -128) happens here
|
||||||
|
// Warning: (207-217): Overflow (resulting value larger than 127) happens here
|
@ -20,6 +20,6 @@ contract C
|
|||||||
// Warning: (165-204): Assertion violation happens here
|
// Warning: (165-204): Assertion violation happens here
|
||||||
// Warning: (208-240): Assertion violation happens here
|
// Warning: (208-240): Assertion violation happens here
|
||||||
// Warning: (244-275): Assertion violation happens here
|
// Warning: (244-275): Assertion violation happens here
|
||||||
// Warning: (311-316): Overflow (resulting value larger than 2**256 - 1) happens here
|
// Warning: (304-332): Assertion violation happens here
|
||||||
// Warning: (336-352): Assertion violation happens here
|
// Warning: (336-352): Assertion violation happens here
|
||||||
// Warning: (356-379): Assertion violation happens here
|
// Warning: (356-379): Assertion violation happens here
|
||||||
|
Loading…
Reference in New Issue
Block a user