solidity/test/libsolidity/GasMeter.cpp
2020-01-07 15:51:50 +01:00

361 lines
11 KiB
C++

/*
This file is part of solidity.
solidity 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.
solidity 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 solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2015
* Unit tests for the gas estimator.
*/
#include <test/libsolidity/SolidityExecutionFramework.h>
#include <libevmasm/GasMeter.h>
#include <libevmasm/KnownState.h>
#include <libevmasm/PathGasMeter.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/interface/GasEstimator.h>
#include <liblangutil/SourceReferenceFormatter.h>
using namespace std;
using namespace solidity::langutil;
using namespace solidity::evmasm;
using namespace solidity::frontend;
using namespace solidity::frontend::test;
namespace solidity::frontend::test
{
class GasMeterTestFramework: public SolidityExecutionFramework
{
public:
void compile(string const& _sourceCode)
{
m_compiler.reset();
m_compiler.setSources({{"", "pragma solidity >=0.0;\n" + _sourceCode}});
m_compiler.setOptimiserSettings(solidity::test::Options::get().optimize);
m_compiler.setEVMVersion(m_evmVersion);
BOOST_REQUIRE_MESSAGE(m_compiler.compile(), "Compiling contract failed");
AssemblyItems const* items = m_compiler.runtimeAssemblyItems(m_compiler.lastContractName());
ASTNode const& sourceUnit = m_compiler.ast("");
BOOST_REQUIRE(items != nullptr);
m_gasCosts = GasEstimator::breakToStatementLevel(
GasEstimator(solidity::test::Options::get().evmVersion()).structuralEstimation(*items, vector<ASTNode const*>({&sourceUnit})),
{&sourceUnit}
);
}
void testCreationTimeGas(string const& _sourceCode, u256 const& _tolerance = u256(0))
{
compileAndRun(_sourceCode);
auto state = make_shared<KnownState>();
PathGasMeter meter(*m_compiler.assemblyItems(m_compiler.lastContractName()), solidity::test::Options::get().evmVersion());
GasMeter::GasConsumption gas = meter.estimateMax(0, state);
u256 bytecodeSize(m_compiler.runtimeObject(m_compiler.lastContractName()).bytecode.size());
// costs for deployment
gas += bytecodeSize * GasCosts::createDataGas;
// costs for transaction
gas += gasForTransaction(m_compiler.object(m_compiler.lastContractName()).bytecode, true);
// Skip the tests when we force ABIEncoderV2.
// TODO: We should enable this again once the yul optimizer is activated.
if (!solidity::test::Options::get().useABIEncoderV2)
{
BOOST_REQUIRE(!gas.isInfinite);
BOOST_CHECK_LE(m_gasUsed, gas.value);
BOOST_CHECK_LE(gas.value - _tolerance, m_gasUsed);
}
}
/// Compares the gas computed by PathGasMeter for the given signature (but unknown arguments)
/// against the actual gas usage computed by the VM on the given set of argument variants.
void testRunTimeGas(string const& _sig, vector<bytes> _argumentVariants, u256 const& _tolerance = u256(0))
{
u256 gasUsed = 0;
GasMeter::GasConsumption gas;
util::FixedHash<4> hash(util::keccak256(_sig));
for (bytes const& arguments: _argumentVariants)
{
sendMessage(hash.asBytes() + arguments, false, 0);
BOOST_CHECK(m_transactionSuccessful);
gasUsed = max(gasUsed, m_gasUsed);
gas = max(gas, gasForTransaction(hash.asBytes() + arguments, false));
}
gas += GasEstimator(solidity::test::Options::get().evmVersion()).functionalEstimation(
*m_compiler.runtimeAssemblyItems(m_compiler.lastContractName()),
_sig
);
// Skip the tests when we force ABIEncoderV2.
// TODO: We should enable this again once the yul optimizer is activated.
if (!solidity::test::Options::get().useABIEncoderV2)
{
BOOST_REQUIRE(!gas.isInfinite);
BOOST_CHECK_LE(m_gasUsed, gas.value);
BOOST_CHECK_LE(gas.value - _tolerance, m_gasUsed);
}
}
static GasMeter::GasConsumption gasForTransaction(bytes const& _data, bool _isCreation)
{
auto evmVersion = solidity::test::Options::get().evmVersion();
GasMeter::GasConsumption gas = _isCreation ? GasCosts::txCreateGas : GasCosts::txGas;
for (auto i: _data)
gas += i != 0 ? GasCosts::txDataNonZeroGas(evmVersion) : GasCosts::txDataZeroGas;
return gas;
}
protected:
map<ASTNode const*, evmasm::GasMeter::GasConsumption> m_gasCosts;
};
BOOST_FIXTURE_TEST_SUITE(GasMeterTests, GasMeterTestFramework)
BOOST_AUTO_TEST_CASE(non_overlapping_filtered_costs)
{
char const* sourceCode = R"(
contract test {
bytes x;
function f(uint a) public returns (uint b) {
for (; a < 200; ++a) {
x.push(0x09);
b = a * a;
}
return f(a - 1);
}
}
)";
compile(sourceCode);
for (auto first = m_gasCosts.cbegin(); first != m_gasCosts.cend(); ++first)
{
auto second = first;
for (++second; second != m_gasCosts.cend(); ++second)
if (first->first->location().intersects(second->first->location()))
{
BOOST_CHECK_MESSAGE(false, "Source locations should not overlap!");
langutil::SourceReferenceFormatter formatter(cout);
formatter.printSourceLocation(&first->first->location());
formatter.printSourceLocation(&second->first->location());
}
}
}
BOOST_AUTO_TEST_CASE(simple_contract)
{
// Tests a simple "deploy contract" code without constructor. The actual contract is not relevant.
char const* sourceCode = R"(
contract test {
bytes32 public shaValue;
function f(uint a) public {
shaValue = keccak256(abi.encodePacked(a));
}
}
)";
testCreationTimeGas(sourceCode);
}
BOOST_AUTO_TEST_CASE(store_keccak256)
{
char const* sourceCode = R"(
contract test {
bytes32 public shaValue;
constructor() public {
shaValue = keccak256(abi.encodePacked(this));
}
}
)";
testCreationTimeGas(sourceCode);
}
BOOST_AUTO_TEST_CASE(updating_store)
{
char const* sourceCode = R"(
contract test {
uint data;
uint data2;
constructor() public {
data = 1;
data = 2;
data2 = 0;
}
}
)";
testCreationTimeGas(sourceCode, m_evmVersion < langutil::EVMVersion::constantinople() ? u256(0) : u256(9600));
}
BOOST_AUTO_TEST_CASE(branches)
{
char const* sourceCode = R"(
contract test {
uint data;
uint data2;
function f(uint x) public {
if (x > 7)
data2 = 1;
else
data = 1;
}
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("f(uint256)", vector<bytes>{encodeArgs(2), encodeArgs(8)});
}
BOOST_AUTO_TEST_CASE(function_calls)
{
char const* sourceCode = R"(
contract test {
uint data;
uint data2;
function f(uint x) public {
if (x > 7)
data2 = g(x**8) + 1;
else
data = 1;
}
function g(uint x) internal returns (uint) {
return data2;
}
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("f(uint256)", vector<bytes>{encodeArgs(2), encodeArgs(8)});
}
BOOST_AUTO_TEST_CASE(multiple_external_functions)
{
char const* sourceCode = R"(
contract test {
uint data;
uint data2;
function f(uint x) public {
if (x > 7)
data2 = g(x**8) + 1;
else
data = 1;
}
function g(uint x) public returns (uint) {
return data2;
}
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("f(uint256)", vector<bytes>{encodeArgs(2), encodeArgs(8)});
testRunTimeGas("g(uint256)", vector<bytes>{encodeArgs(2)});
}
BOOST_AUTO_TEST_CASE(exponent_size)
{
char const* sourceCode = R"(
contract A {
function g(uint x) public returns (uint) {
return x ** 0x100;
}
function h(uint x) public returns (uint) {
return x ** 0x10000;
}
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("g(uint256)", vector<bytes>{encodeArgs(2)});
testRunTimeGas("h(uint256)", vector<bytes>{encodeArgs(2)});
}
BOOST_AUTO_TEST_CASE(balance_gas)
{
char const* sourceCode = R"(
contract A {
function lookup_balance(address a) public returns (uint) {
return a.balance;
}
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("lookup_balance(address)", vector<bytes>{encodeArgs(2), encodeArgs(100)});
}
BOOST_AUTO_TEST_CASE(extcodesize_gas)
{
char const* sourceCode = R"(
contract A {
function f() public returns (uint _s) {
assembly {
_s := extcodesize(0x30)
}
}
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("f()", vector<bytes>{encodeArgs()});
}
BOOST_AUTO_TEST_CASE(regular_functions_exclude_fallback)
{
// A bug in the estimator caused the costs for a specific function
// to always include the costs for the fallback.
char const* sourceCode = R"(
contract A {
uint public x;
fallback() external { x = 2; }
}
)";
testCreationTimeGas(sourceCode);
testRunTimeGas("x()", vector<bytes>{encodeArgs()});
}
BOOST_AUTO_TEST_CASE(complex_control_flow)
{
// This crashed the gas estimator previously (or took a very long time).
// Now we do not follow branches if they start out with lower gas costs than the ones
// we previously considered. This of course reduces accuracy.
char const* sourceCode = R"(
contract log {
function ln(int128 x) public pure returns (int128 result) {
int128 t = x / 256;
int128 y = 5545177;
x = t;
t = x * 16; if (t <= 1000000) { x = t; y = y - 2772588; }
t = x * 4; if (t <= 1000000) { x = t; y = y - 1386294; }
t = x * 2; if (t <= 1000000) { x = t; y = y - 693147; }
t = x + x / 2; if (t <= 1000000) { x = t; y = y - 405465; }
t = x + x / 4; if (t <= 1000000) { x = t; y = y - 223144; }
t = x + x / 8; if (t <= 1000000) { x = t; y = y - 117783; }
t = x + x / 16; if (t <= 1000000) { x = t; y = y - 60624; }
t = x + x / 32; if (t <= 1000000) { x = t; y = y - 30771; }
t = x + x / 64; if (t <= 1000000) { x = t; y = y - 15504; }
t = x + x / 128; if (t <= 1000000) { x = t; y = y - 7782; }
t = x + x / 256; if (t <= 1000000) { x = t; y = y - 3898; }
t = x + x / 512; if (t <= 1000000) { x = t; y = y - 1951; }
t = x + x / 1024; if (t <= 1000000) { x = t; y = y - 976; }
t = x + x / 2048; if (t <= 1000000) { x = t; y = y - 488; }
t = x + x / 4096; if (t <= 1000000) { x = t; y = y - 244; }
t = x + x / 8192; if (t <= 1000000) { x = t; y = y - 122; }
t = x + x / 16384; if (t <= 1000000) { x = t; y = y - 61; }
t = x + x / 32768; if (t <= 1000000) { x = t; y = y - 31; }
t = x + x / 65536; if (t <= 1000000) { y = y - 15; }
return y;
}
}
)";
testCreationTimeGas(sourceCode);
// max gas is used for small x
testRunTimeGas("ln(int128)", vector<bytes>{encodeArgs(0), encodeArgs(10), encodeArgs(105), encodeArgs(30000)});
}
BOOST_AUTO_TEST_SUITE_END()
}