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Add mini-interpreter to check representation.

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chriseth
2019-05-28 11:35:07 +02:00
parent 1c16124a09
commit cee1340113
3 changed files with 72 additions and 14 deletions
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libyul/optimiser/ConstantOptimiser.cpp
+58
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@@ -35,6 +35,63 @@ using namespace yul;
using Representation = ConstantOptimiser::Representation;
namespace
{
struct MiniEVMInterpreter: boost::static_visitor<u256>
{
explicit MiniEVMInterpreter(EVMDialect const& _dialect): m_dialect(_dialect) {}
u256 eval(Expression const& _expr)
{
return boost::apply_visitor(*this, _expr);
}
u256 eval(dev::eth::Instruction _instr, vector<Expression> const& _arguments)
{
vector<u256> args;
for (auto const& arg: _arguments)
args.emplace_back(eval(arg));
switch (_instr)
{
case eth::Instruction::ADD:
return args.at(0) + args.at(1);
case eth::Instruction::SUB:
return args.at(0) - args.at(1);
case eth::Instruction::MUL:
return args.at(0) * args.at(1);
case eth::Instruction::EXP:
return exp256(args.at(0), args.at(1));
case eth::Instruction::SHL:
return args.at(0) > 255 ? 0 : (args.at(1) << unsigned(args.at(0)));
case eth::Instruction::NOT:
return ~args.at(0);
default:
yulAssert(false, "Invalid operation generated in constant optimizer.");
}
return 0;
}
u256 operator()(FunctionalInstruction const& _instr)
{
return eval(_instr.instruction, _instr.arguments);
}
u256 operator()(FunctionCall const& _funCall)
{
BuiltinFunctionForEVM const* fun = m_dialect.builtin(_funCall.functionName.name);
yulAssert(fun, "Expected builtin function.");
yulAssert(fun->instruction, "Expected EVM instruction.");
return eval(*fun->instruction, _funCall.arguments);
}
u256 operator()(Literal const& _literal)
{
return valueOfLiteral(_literal);
}
u256 operator()(Identifier const&) { yulAssert(false, ""); }
EVMDialect const& m_dialect;
};
}
void ConstantOptimiser::visit(Expression& _e)
{
if (_e.type() == typeid(Literal))
@@ -118,6 +175,7 @@ Representation const& RepresentationFinder::findRepresentation(dev::u256 const&
m_maxSteps--;
routine = min(move(routine), move(newRoutine));
}
yulAssert(MiniEVMInterpreter{m_dialect}.eval(*routine.expression) == _value, "Invalid expression generated.");
return m_cache[_value] = move(routine);
}