236 lines
8.9 KiB
236 lines
8.9 KiB
/*
|
|
This file is part of cpp-ethereum.
|
|
|
|
cpp-ethereum 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.
|
|
|
|
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
/**
|
|
* @file ExpressionClasses.cpp
|
|
* @author Christian <c@ethdev.com>
|
|
* @date 2015
|
|
* Container for equivalence classes of expressions for use in common subexpression elimination.
|
|
*/
|
|
|
|
#include <libevmcore/ExpressionClasses.h>
|
|
#include <utility>
|
|
#include <tuple>
|
|
#include <functional>
|
|
#include <boost/range/adaptor/reversed.hpp>
|
|
#include <libevmcore/Assembly.h>
|
|
#include <libevmcore/CommonSubexpressionEliminator.h>
|
|
|
|
using namespace std;
|
|
using namespace dev;
|
|
using namespace dev::eth;
|
|
|
|
|
|
bool ExpressionClasses::Expression::operator<(const ExpressionClasses::Expression& _other) const
|
|
{
|
|
auto type = item->type();
|
|
auto otherType = _other.item->type();
|
|
return std::tie(type, item->data(), arguments) <
|
|
std::tie(otherType, _other.item->data(), _other.arguments);
|
|
}
|
|
|
|
ExpressionClasses::Id ExpressionClasses::find(AssemblyItem const& _item, Ids const& _arguments)
|
|
{
|
|
Expression exp;
|
|
exp.item = &_item;
|
|
exp.arguments = _arguments;
|
|
|
|
if (SemanticInformation::isCommutativeOperation(_item))
|
|
sort(exp.arguments.begin(), exp.arguments.end());
|
|
|
|
//@todo store all class members (not only the representatives) in an efficient data structure to search here
|
|
for (Expression const& e: m_representatives)
|
|
if (!(e < exp || exp < e))
|
|
return e.id;
|
|
|
|
if (SemanticInformation::isDupInstruction(_item))
|
|
{
|
|
// Special item that refers to values pre-existing on the stack
|
|
m_spareAssemblyItem.push_back(make_shared<AssemblyItem>(_item));
|
|
exp.item = m_spareAssemblyItem.back().get();
|
|
}
|
|
|
|
ExpressionClasses::Id id = tryToSimplify(exp);
|
|
if (id < m_representatives.size())
|
|
return id;
|
|
|
|
exp.id = m_representatives.size();
|
|
m_representatives.push_back(exp);
|
|
return exp.id;
|
|
}
|
|
|
|
ExpressionClasses::Id ExpressionClasses::tryToSimplify(Expression const& _expr, bool _secondRun)
|
|
{
|
|
if (_expr.item->type() != Operation)
|
|
return -1;
|
|
|
|
// @todo:
|
|
// ISZERO ISZERO
|
|
// associative operations (as done in Assembly.cpp)
|
|
// 2 * x == x + x
|
|
|
|
Id arg1;
|
|
Id arg2;
|
|
Id arg3;
|
|
u256 data1;
|
|
u256 data2;
|
|
u256 data3;
|
|
switch (_expr.arguments.size())
|
|
{
|
|
default:
|
|
arg3 = _expr.arguments.at(2);
|
|
data3 = representative(arg3).item->data();
|
|
case 2:
|
|
arg2 = _expr.arguments.at(1);
|
|
data2 = representative(arg2).item->data();
|
|
case 1:
|
|
arg1 = _expr.arguments.at(0);
|
|
data1 = representative(arg1).item->data();
|
|
case 0:
|
|
break;
|
|
}
|
|
|
|
/**
|
|
* Simplification rule. If _strict is false, Push or a constant matches any constant,
|
|
* otherwise Push matches "0" and a constant matches itself.
|
|
* "UndefinedItem" matches any expression, but all of them must be equal inside one rule.
|
|
*/
|
|
struct Rule
|
|
{
|
|
Rule(AssemblyItems const& _pattern, bool _strict, function<AssemblyItem()> const& _action):
|
|
pattern(_pattern),
|
|
assemblyItemAction(_action),
|
|
strict(_strict)
|
|
{}
|
|
Rule(AssemblyItems const& _pattern, function<AssemblyItem()> _action):
|
|
Rule(_pattern, false, _action)
|
|
{}
|
|
Rule(AssemblyItems const& _pattern, bool _strict, function<Id()> const& _action):
|
|
pattern(_pattern),
|
|
idAction(_action),
|
|
strict(_strict)
|
|
{}
|
|
Rule(AssemblyItems const& _pattern, function<Id()> _action):
|
|
Rule(_pattern, false, _action)
|
|
{}
|
|
bool matches(ExpressionClasses const& _classes, Expression const& _expr) const
|
|
{
|
|
if (!_expr.item->match(pattern.front()))
|
|
return false;
|
|
assertThrow(_expr.arguments.size() == pattern.size() - 1, OptimizerException, "");
|
|
Id argRequiredToBeEqual(-1);
|
|
for (size_t i = 1; i < pattern.size(); ++i)
|
|
{
|
|
Id arg = _expr.arguments[i - 1];
|
|
if (pattern[i].type() == UndefinedItem)
|
|
{
|
|
if (argRequiredToBeEqual == Id(-1))
|
|
argRequiredToBeEqual = arg;
|
|
else if (argRequiredToBeEqual != arg)
|
|
return false;
|
|
}
|
|
else
|
|
{
|
|
AssemblyItem const& argItem = *_classes.representative(arg).item;
|
|
if (strict && argItem != pattern[i])
|
|
return false;
|
|
else if (!strict && !argItem.match(pattern[i]))
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
AssemblyItems pattern;
|
|
function<AssemblyItem()> assemblyItemAction;
|
|
function<Id()> idAction;
|
|
bool strict;
|
|
};
|
|
|
|
vector<Rule> c_singleLevel{
|
|
// arithmetics on constants involving only stack variables
|
|
{{Instruction::ADD, Push, Push}, [&]{ return data1 + data2; }},
|
|
{{Instruction::MUL, Push, Push}, [&]{ return data1 * data2; }},
|
|
{{Instruction::SUB, Push, Push}, [&]{ return data1 - data2; }},
|
|
{{Instruction::DIV, Push, Push}, [&]{ return data2 == 0 ? 0 : data1 / data2; }},
|
|
{{Instruction::SDIV, Push, Push}, [&]{ return data2 == 0 ? 0 : s2u(u2s(data1) / u2s(data2)); }},
|
|
{{Instruction::MOD, Push, Push}, [&]{ return data2 == 0 ? 0 : data1 % data2; }},
|
|
{{Instruction::SMOD, Push, Push}, [&]{ return data2 == 0 ? 0 : s2u(u2s(data1) % u2s(data2)); }},
|
|
{{Instruction::EXP, Push, Push}, [&]{ return u256(boost::multiprecision::powm(bigint(data1), bigint(data2), bigint(1) << 256)); }},
|
|
{{Instruction::NOT, Push}, [&]{ return ~data1; }},
|
|
{{Instruction::LT, Push, Push}, [&]() -> u256 { return data1 < data2 ? 1 : 0; }},
|
|
{{Instruction::GT, Push, Push}, [&]() -> u256 { return data1 > data2 ? 1 : 0; }},
|
|
{{Instruction::SLT, Push, Push}, [&]() -> u256 { return u2s(data1) < u2s( data2) ? 1 : 0; }},
|
|
{{Instruction::SGT, Push, Push}, [&]() -> u256 { return u2s(data1) > u2s( data2) ? 1 : 0; }},
|
|
{{Instruction::EQ, Push, Push}, [&]() -> u256 { return data1 == data2 ? 1 : 0; }},
|
|
{{Instruction::ISZERO, Push}, [&]() -> u256 { return data1 == 0 ? 1 : 0; }},
|
|
{{Instruction::AND, Push, Push}, [&]{ return data1 & data2; }},
|
|
{{Instruction::OR, Push, Push}, [&]{ return data1 | data2; }},
|
|
{{Instruction::XOR, Push, Push}, [&]{ return data1 ^ data2; }},
|
|
{{Instruction::BYTE, Push, Push}, [&]{ return data1 >= 32 ? 0 : (data2 >> unsigned(8 * (31 - data1))) & 0xff; }},
|
|
{{Instruction::ADDMOD, Push, Push, Push}, [&]{ return data3 == 0 ? 0 : u256((bigint(data1) + bigint(data2)) % data3); }},
|
|
{{Instruction::MULMOD, Push, Push, Push}, [&]{ return data3 == 0 ? 0 : u256((bigint(data1) * bigint(data2)) % data3); }},
|
|
{{Instruction::MULMOD, Push, Push, Push}, [&]{ return data1 * data2; }},
|
|
{{Instruction::SIGNEXTEND, Push, Push}, [&]{
|
|
if (data1 >= 31)
|
|
return data2;
|
|
unsigned testBit = unsigned(data1) * 8 + 7;
|
|
u256 mask = (u256(1) << testBit) - 1;
|
|
return u256(boost::multiprecision::bit_test(data2, testBit) ? data2 | ~mask : data2 & mask);
|
|
}},
|
|
{{Instruction::ADD, UndefinedItem, u256(0)}, true, [&]{ return arg1; }},
|
|
{{Instruction::MUL, UndefinedItem, u256(1)}, true, [&]{ return arg1; }},
|
|
{{Instruction::OR, UndefinedItem, u256(0)}, true, [&]{ return arg1; }},
|
|
{{Instruction::XOR, UndefinedItem, u256(0)}, true, [&]{ return arg1; }},
|
|
{{Instruction::AND, UndefinedItem, ~u256(0)}, true, [&]{ return arg1; }},
|
|
{{Instruction::MUL, UndefinedItem, u256(0)}, true, [&]{ return u256(0); }},
|
|
{{Instruction::DIV, UndefinedItem, u256(0)}, true, [&]{ return u256(0); }},
|
|
{{Instruction::MOD, UndefinedItem, u256(0)}, true, [&]{ return u256(0); }},
|
|
{{Instruction::MOD, u256(0), UndefinedItem}, true, [&]{ return u256(0); }},
|
|
{{Instruction::AND, UndefinedItem, u256(0)}, true, [&]{ return u256(0); }},
|
|
{{Instruction::OR, UndefinedItem, ~u256(0)}, true, [&]{ return ~u256(0); }},
|
|
{{Instruction::AND, UndefinedItem, UndefinedItem}, true, [&]{ return arg1; }},
|
|
{{Instruction::OR, UndefinedItem, UndefinedItem}, true, [&]{ return arg1; }},
|
|
{{Instruction::SUB, UndefinedItem, UndefinedItem}, true, [&]{ return u256(0); }},
|
|
{{Instruction::EQ, UndefinedItem, UndefinedItem}, true, [&]{ return u256(1); }},
|
|
{{Instruction::LT, UndefinedItem, UndefinedItem}, true, [&]{ return u256(0); }},
|
|
{{Instruction::SLT, UndefinedItem, UndefinedItem}, true, [&]{ return u256(0); }},
|
|
{{Instruction::GT, UndefinedItem, UndefinedItem}, true, [&]{ return u256(0); }},
|
|
{{Instruction::SGT, UndefinedItem, UndefinedItem}, true, [&]{ return u256(0); }},
|
|
{{Instruction::MOD, UndefinedItem, UndefinedItem}, true, [&]{ return u256(0); }},
|
|
};
|
|
|
|
for (auto const& rule: c_singleLevel)
|
|
if (rule.matches(*this, _expr))
|
|
{
|
|
if (rule.idAction)
|
|
return rule.idAction();
|
|
else
|
|
{
|
|
m_spareAssemblyItem.push_back(make_shared<AssemblyItem>(rule.assemblyItemAction()));
|
|
return find(*m_spareAssemblyItem.back());
|
|
}
|
|
}
|
|
|
|
if (!_secondRun && _expr.arguments.size() == 2 && SemanticInformation::isCommutativeOperation(*_expr.item))
|
|
{
|
|
Expression expr = _expr;
|
|
swap(expr.arguments[0], expr.arguments[1]);
|
|
return tryToSimplify(expr, true);
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|