solidity/ExpressionCompiler.cpp
2015-03-16 18:07:14 +01:00

1174 lines
44 KiB
C++

/*
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/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Solidity AST to EVM bytecode compiler for expressions.
*/
#include <utility>
#include <numeric>
#include <boost/range/adaptor/reversed.hpp>
#include <libdevcore/Common.h>
#include <libdevcrypto/SHA3.h>
#include <libsolidity/AST.h>
#include <libsolidity/ExpressionCompiler.h>
#include <libsolidity/CompilerContext.h>
#include <libsolidity/CompilerUtils.h>
#include <libsolidity/LValue.h>
using namespace std;
namespace dev
{
namespace solidity
{
void ExpressionCompiler::compile(Expression const& _expression)
{
_expression.accept(*this);
}
void ExpressionCompiler::appendStateVariableInitialization(VariableDeclaration const& _varDecl)
{
if (!_varDecl.getValue())
return;
solAssert(!!_varDecl.getValue()->getType(), "Type information not available.");
CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
_varDecl.getValue()->accept(*this);
appendTypeConversion(*_varDecl.getValue()->getType(), *_varDecl.getType(), true);
StorageItem(m_context, _varDecl).storeValue(*_varDecl.getType(), _varDecl.getLocation(), true);
}
void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)
{
CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
FunctionType accessorType(_varDecl);
unsigned length = 0;
TypePointers const& paramTypes = accessorType.getParameterTypes();
// move arguments to memory
for (TypePointer const& paramType: boost::adaptors::reverse(paramTypes))
length += CompilerUtils(m_context).storeInMemory(length, *paramType, true);
// retrieve the position of the variable
auto const& location = m_context.getStorageLocationOfVariable(_varDecl);
m_context << location.first;
TypePointer returnType = _varDecl.getType();
for (TypePointer const& paramType: paramTypes)
{
// move offset to memory
CompilerUtils(m_context).storeInMemory(length);
unsigned argLen = paramType->getCalldataEncodedSize();
length -= argLen;
m_context << u256(argLen + 32) << u256(length) << eth::Instruction::SHA3;
returnType = dynamic_cast<MappingType const&>(*returnType).getValueType();
}
unsigned retSizeOnStack = 0;
solAssert(accessorType.getReturnParameterTypes().size() >= 1, "");
if (StructType const* structType = dynamic_cast<StructType const*>(returnType.get()))
{
auto const& names = accessorType.getReturnParameterNames();
auto const& types = accessorType.getReturnParameterTypes();
// struct
for (size_t i = 0; i < names.size(); ++i)
{
if (types[i]->getCategory() == Type::Category::Mapping)
continue;
pair<u256, unsigned> const& offsets = structType->getStorageOffsetsOfMember(names[i]);
m_context << eth::Instruction::DUP1 << u256(offsets.first) << eth::Instruction::ADD << u256(offsets.second);
StorageItem(m_context, *types[i]).retrieveValue(SourceLocation(), true);
solAssert(types[i]->getSizeOnStack() == 1, "Returning struct elements with stack size != 1 not yet implemented.");
m_context << eth::Instruction::SWAP1;
retSizeOnStack += types[i]->getSizeOnStack();
}
m_context << eth::Instruction::POP;
}
else
{
// simple value
solAssert(accessorType.getReturnParameterTypes().size() == 1, "");
m_context << u256(location.second);
StorageItem(m_context, *returnType).retrieveValue(SourceLocation(), true);
retSizeOnStack = returnType->getSizeOnStack();
}
solAssert(retSizeOnStack <= 15, "Stack too deep.");
m_context << eth::dupInstruction(retSizeOnStack + 1);
m_context.appendJump(eth::AssemblyItem::JumpType::OutOfFunction);
}
void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type const& _targetType, bool _cleanupNeeded)
{
// For a type extension, we need to remove all higher-order bits that we might have ignored in
// previous operations.
// @todo: store in the AST whether the operand might have "dirty" higher order bits
if (_typeOnStack == _targetType && !_cleanupNeeded)
return;
Type::Category stackTypeCategory = _typeOnStack.getCategory();
Type::Category targetTypeCategory = _targetType.getCategory();
switch (stackTypeCategory)
{
case Type::Category::FixedBytes:
{
FixedBytesType const& typeOnStack = dynamic_cast<FixedBytesType const&>(_typeOnStack);
if (targetTypeCategory == Type::Category::Integer)
{
// conversion from bytes to integer. no need to clean the high bit
// only to shift right because of opposite alignment
IntegerType const& targetIntegerType = dynamic_cast<IntegerType const&>(_targetType);
m_context << (u256(1) << (256 - typeOnStack.getNumBytes() * 8)) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
if (targetIntegerType.getNumBits() < typeOnStack.getNumBytes() * 8)
appendTypeConversion(IntegerType(typeOnStack.getNumBytes() * 8), _targetType, _cleanupNeeded);
}
else
{
// clear lower-order bytes for conversion to shorter bytes - we always clean
solAssert(targetTypeCategory == Type::Category::FixedBytes, "Invalid type conversion requested.");
FixedBytesType const& targetType = dynamic_cast<FixedBytesType const&>(_targetType);
if (targetType.getNumBytes() < typeOnStack.getNumBytes())
{
if (targetType.getNumBytes() == 0)
m_context << eth::Instruction::DUP1 << eth::Instruction::XOR;
else
m_context << (u256(1) << (256 - targetType.getNumBytes() * 8))
<< eth::Instruction::DUP1 << eth::Instruction::SWAP2
<< eth::Instruction::DIV << eth::Instruction::MUL;
}
}
}
break;
case Type::Category::Enum:
solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Enum, "");
break;
case Type::Category::Integer:
case Type::Category::Contract:
case Type::Category::IntegerConstant:
if (targetTypeCategory == Type::Category::FixedBytes)
{
solAssert(stackTypeCategory == Type::Category::Integer || stackTypeCategory == Type::Category::IntegerConstant,
"Invalid conversion to FixedBytesType requested.");
// conversion from bytes to string. no need to clean the high bit
// only to shift left because of opposite alignment
FixedBytesType const& targetBytesType = dynamic_cast<FixedBytesType const&>(_targetType);
if (auto typeOnStack = dynamic_cast<IntegerType const*>(&_typeOnStack))
if (targetBytesType.getNumBytes() * 8 > typeOnStack->getNumBits())
appendHighBitsCleanup(*typeOnStack);
m_context << (u256(1) << (256 - targetBytesType.getNumBytes() * 8)) << eth::Instruction::MUL;
}
else if (targetTypeCategory == Type::Category::Enum)
// just clean
appendTypeConversion(_typeOnStack, *_typeOnStack.getRealType(), true);
else
{
solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Contract, "");
IntegerType addressType(0, IntegerType::Modifier::Address);
IntegerType const& targetType = targetTypeCategory == Type::Category::Integer
? dynamic_cast<IntegerType const&>(_targetType) : addressType;
if (stackTypeCategory == Type::Category::IntegerConstant)
{
IntegerConstantType const& constType = dynamic_cast<IntegerConstantType const&>(_typeOnStack);
// We know that the stack is clean, we only have to clean for a narrowing conversion
// where cleanup is forced.
if (targetType.getNumBits() < constType.getIntegerType()->getNumBits() && _cleanupNeeded)
appendHighBitsCleanup(targetType);
}
else
{
IntegerType const& typeOnStack = stackTypeCategory == Type::Category::Integer
? dynamic_cast<IntegerType const&>(_typeOnStack) : addressType;
// Widening: clean up according to source type width
// Non-widening and force: clean up according to target type bits
if (targetType.getNumBits() > typeOnStack.getNumBits())
appendHighBitsCleanup(typeOnStack);
else if (_cleanupNeeded)
appendHighBitsCleanup(targetType);
}
}
break;
default:
// All other types should not be convertible to non-equal types.
solAssert(_typeOnStack == _targetType, "Invalid type conversion requested.");
break;
}
}
bool ExpressionCompiler::visit(Assignment const& _assignment)
{
CompilerContext::LocationSetter locationSetter(m_context, _assignment);
_assignment.getRightHandSide().accept(*this);
if (_assignment.getType()->isValueType())
appendTypeConversion(*_assignment.getRightHandSide().getType(), *_assignment.getType());
_assignment.getLeftHandSide().accept(*this);
solAssert(!!m_currentLValue, "LValue not retrieved.");
Token::Value op = _assignment.getAssignmentOperator();
if (op != Token::Assign) // compound assignment
{
solAssert(_assignment.getType()->isValueType(), "Compound operators not implemented for non-value types.");
unsigned lvalueSize = m_currentLValue->sizeOnStack();
unsigned itemSize = _assignment.getType()->getSizeOnStack();
if (lvalueSize > 0)
{
CompilerUtils(m_context).copyToStackTop(lvalueSize + itemSize, itemSize);
CompilerUtils(m_context).copyToStackTop(itemSize + lvalueSize, lvalueSize);
// value lvalue_ref value lvalue_ref
}
m_currentLValue->retrieveValue(_assignment.getLocation(), true);
appendOrdinaryBinaryOperatorCode(Token::AssignmentToBinaryOp(op), *_assignment.getType());
if (lvalueSize > 0)
{
solAssert(itemSize + lvalueSize <= 16, "Stack too deep.");
// value [lvalue_ref] updated_value
for (unsigned i = 0; i < itemSize; ++i)
m_context << eth::swapInstruction(itemSize + lvalueSize) << eth::Instruction::POP;
}
}
m_currentLValue->storeValue(*_assignment.getRightHandSide().getType(), _assignment.getLocation());
m_currentLValue.reset();
return false;
}
bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
{
CompilerContext::LocationSetter locationSetter(m_context, _unaryOperation);
//@todo type checking and creating code for an operator should be in the same place:
// the operator should know how to convert itself and to which types it applies, so
// put this code together with "Type::acceptsBinary/UnaryOperator" into a class that
// represents the operator
if (_unaryOperation.getType()->getCategory() == Type::Category::IntegerConstant)
{
m_context << _unaryOperation.getType()->literalValue(nullptr);
return false;
}
_unaryOperation.getSubExpression().accept(*this);
switch (_unaryOperation.getOperator())
{
case Token::Not: // !
m_context << eth::Instruction::ISZERO;
break;
case Token::BitNot: // ~
m_context << eth::Instruction::NOT;
break;
case Token::After: // after
m_context << eth::Instruction::TIMESTAMP << eth::Instruction::ADD;
break;
case Token::Delete: // delete
solAssert(!!m_currentLValue, "LValue not retrieved.");
m_currentLValue->setToZero(_unaryOperation.getLocation());
m_currentLValue.reset();
break;
case Token::Inc: // ++ (pre- or postfix)
case Token::Dec: // -- (pre- or postfix)
solAssert(!!m_currentLValue, "LValue not retrieved.");
m_currentLValue->retrieveValue(_unaryOperation.getLocation());
if (!_unaryOperation.isPrefixOperation())
{
// store value for later
solAssert(_unaryOperation.getType()->getSizeOnStack() == 1, "Stack size != 1 not implemented.");
m_context << eth::Instruction::DUP1;
if (m_currentLValue->sizeOnStack() > 0)
for (unsigned i = 1 + m_currentLValue->sizeOnStack(); i > 0; --i)
m_context << eth::swapInstruction(i);
}
m_context << u256(1);
if (_unaryOperation.getOperator() == Token::Inc)
m_context << eth::Instruction::ADD;
else
m_context << eth::Instruction::SWAP1 << eth::Instruction::SUB;
// Stack for prefix: [ref...] (*ref)+-1
// Stack for postfix: *ref [ref...] (*ref)+-1
for (unsigned i = m_currentLValue->sizeOnStack(); i > 0; --i)
m_context << eth::swapInstruction(i);
m_currentLValue->storeValue(
*_unaryOperation.getType(), _unaryOperation.getLocation(),
!_unaryOperation.isPrefixOperation());
m_currentLValue.reset();
break;
case Token::Add: // +
// unary add, so basically no-op
break;
case Token::Sub: // -
m_context << u256(0) << eth::Instruction::SUB;
break;
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid unary operator: " +
string(Token::toString(_unaryOperation.getOperator()))));
}
return false;
}
bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
{
CompilerContext::LocationSetter locationSetter(m_context, _binaryOperation);
Expression const& leftExpression = _binaryOperation.getLeftExpression();
Expression const& rightExpression = _binaryOperation.getRightExpression();
Type const& commonType = _binaryOperation.getCommonType();
Token::Value const c_op = _binaryOperation.getOperator();
if (c_op == Token::And || c_op == Token::Or) // special case: short-circuiting
appendAndOrOperatorCode(_binaryOperation);
else if (commonType.getCategory() == Type::Category::IntegerConstant)
m_context << commonType.literalValue(nullptr);
else
{
bool cleanupNeeded = commonType.getCategory() == Type::Category::Integer &&
(Token::isCompareOp(c_op) || c_op == Token::Div || c_op == Token::Mod);
// for commutative operators, push the literal as late as possible to allow improved optimization
auto isLiteral = [](Expression const& _e)
{
return dynamic_cast<Literal const*>(&_e) || _e.getType()->getCategory() == Type::Category::IntegerConstant;
};
bool swap = m_optimize && Token::isCommutativeOp(c_op) && isLiteral(rightExpression) && !isLiteral(leftExpression);
if (swap)
{
leftExpression.accept(*this);
appendTypeConversion(*leftExpression.getType(), commonType, cleanupNeeded);
rightExpression.accept(*this);
appendTypeConversion(*rightExpression.getType(), commonType, cleanupNeeded);
}
else
{
rightExpression.accept(*this);
appendTypeConversion(*rightExpression.getType(), commonType, cleanupNeeded);
leftExpression.accept(*this);
appendTypeConversion(*leftExpression.getType(), commonType, cleanupNeeded);
}
if (Token::isCompareOp(c_op))
appendCompareOperatorCode(c_op, commonType);
else
appendOrdinaryBinaryOperatorCode(c_op, commonType);
}
// do not visit the child nodes, we already did that explicitly
return false;
}
bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
{
CompilerContext::LocationSetter locationSetter(m_context, _functionCall);
using Location = FunctionType::Location;
if (_functionCall.isTypeConversion())
{
//@todo struct construction
solAssert(_functionCall.getArguments().size() == 1, "");
solAssert(_functionCall.getNames().empty(), "");
Expression const& firstArgument = *_functionCall.getArguments().front();
firstArgument.accept(*this);
appendTypeConversion(*firstArgument.getType(), *_functionCall.getType());
}
else
{
FunctionType const& function = dynamic_cast<FunctionType const&>(*_functionCall.getExpression().getType());
TypePointers const& parameterTypes = function.getParameterTypes();
vector<ASTPointer<Expression const>> const& callArguments = _functionCall.getArguments();
vector<ASTPointer<ASTString>> const& callArgumentNames = _functionCall.getNames();
if (!function.takesArbitraryParameters())
solAssert(callArguments.size() == parameterTypes.size(), "");
vector<ASTPointer<Expression const>> arguments;
if (callArgumentNames.empty())
// normal arguments
arguments = callArguments;
else
// named arguments
for (auto const& parameterName: function.getParameterNames())
{
bool found = false;
for (size_t j = 0; j < callArgumentNames.size() && !found; j++)
if ((found = (parameterName == *callArgumentNames[j])))
// we found the actual parameter position
arguments.push_back(callArguments[j]);
solAssert(found, "");
}
switch (function.getLocation())
{
case Location::Internal:
{
// Calling convention: Caller pushes return address and arguments
// Callee removes them and pushes return values
eth::AssemblyItem returnLabel = m_context.pushNewTag();
for (unsigned i = 0; i < arguments.size(); ++i)
{
arguments[i]->accept(*this);
appendTypeConversion(*arguments[i]->getType(), *function.getParameterTypes()[i]);
}
_functionCall.getExpression().accept(*this);
m_context.appendJump(eth::AssemblyItem::JumpType::IntoFunction);
m_context << returnLabel;
unsigned returnParametersSize = CompilerUtils::getSizeOnStack(function.getReturnParameterTypes());
// callee adds return parameters, but removes arguments and return label
m_context.adjustStackOffset(returnParametersSize - CompilerUtils::getSizeOnStack(function.getParameterTypes()) - 1);
// @todo for now, the return value of a function is its first return value, so remove
// all others
for (unsigned i = 1; i < function.getReturnParameterTypes().size(); ++i)
CompilerUtils(m_context).popStackElement(*function.getReturnParameterTypes()[i]);
break;
}
case Location::External:
case Location::Bare:
_functionCall.getExpression().accept(*this);
appendExternalFunctionCall(function, arguments, function.getLocation() == Location::Bare);
break;
case Location::Creation:
{
_functionCall.getExpression().accept(*this);
solAssert(!function.gasSet(), "Gas limit set for contract creation.");
solAssert(function.getReturnParameterTypes().size() == 1, "");
ContractDefinition const& contract = dynamic_cast<ContractType const&>(
*function.getReturnParameterTypes().front()).getContractDefinition();
// copy the contract's code into memory
bytes const& bytecode = m_context.getCompiledContract(contract);
m_context << u256(bytecode.size());
//@todo could be done by actually appending the Assembly, but then we probably need to compile
// multiple times. Will revisit once external fuctions are inlined.
m_context.appendData(bytecode);
//@todo copy to memory position 0, shift as soon as we use memory
m_context << u256(0) << eth::Instruction::CODECOPY;
m_context << u256(bytecode.size());
appendArgumentsCopyToMemory(arguments, function.getParameterTypes());
// size, offset, endowment
m_context << u256(0);
if (function.valueSet())
m_context << eth::dupInstruction(3);
else
m_context << u256(0);
m_context << eth::Instruction::CREATE;
if (function.valueSet())
m_context << eth::swapInstruction(1) << eth::Instruction::POP;
break;
}
case Location::SetGas:
{
// stack layout: contract_address function_id [gas] [value]
_functionCall.getExpression().accept(*this);
arguments.front()->accept(*this);
appendTypeConversion(*arguments.front()->getType(), IntegerType(256), true);
// Note that function is not the original function, but the ".gas" function.
// Its values of gasSet and valueSet is equal to the original function's though.
unsigned stackDepth = (function.gasSet() ? 1 : 0) + (function.valueSet() ? 1 : 0);
if (stackDepth > 0)
m_context << eth::swapInstruction(stackDepth);
if (function.gasSet())
m_context << eth::Instruction::POP;
break;
}
case Location::SetValue:
// stack layout: contract_address function_id [gas] [value]
_functionCall.getExpression().accept(*this);
// Note that function is not the original function, but the ".value" function.
// Its values of gasSet and valueSet is equal to the original function's though.
if (function.valueSet())
m_context << eth::Instruction::POP;
arguments.front()->accept(*this);
break;
case Location::Send:
_functionCall.getExpression().accept(*this);
m_context << u256(0); // 0 gas, we do not want to execute code
arguments.front()->accept(*this);
appendTypeConversion(*arguments.front()->getType(),
*function.getParameterTypes().front(), true);
appendExternalFunctionCall(FunctionType(TypePointers{}, TypePointers{},
Location::External, false, true, true), {}, true);
break;
case Location::Suicide:
arguments.front()->accept(*this);
appendTypeConversion(*arguments.front()->getType(), *function.getParameterTypes().front(), true);
m_context << eth::Instruction::SUICIDE;
break;
case Location::SHA3:
{
m_context << u256(0);
appendArgumentsCopyToMemory(arguments, TypePointers(), function.padArguments());
m_context << u256(0) << eth::Instruction::SHA3;
break;
}
case Location::Log0:
case Location::Log1:
case Location::Log2:
case Location::Log3:
case Location::Log4:
{
unsigned logNumber = int(function.getLocation()) - int(Location::Log0);
for (unsigned arg = logNumber; arg > 0; --arg)
{
arguments[arg]->accept(*this);
appendTypeConversion(*arguments[arg]->getType(), *function.getParameterTypes()[arg], true);
}
m_context << u256(0);
appendExpressionCopyToMemory(*function.getParameterTypes().front(), *arguments.front());
m_context << u256(0) << eth::logInstruction(logNumber);
break;
}
case Location::Event:
{
_functionCall.getExpression().accept(*this);
auto const& event = dynamic_cast<EventDefinition const&>(function.getDeclaration());
unsigned numIndexed = 0;
// All indexed arguments go to the stack
for (unsigned arg = arguments.size(); arg > 0; --arg)
if (event.getParameters()[arg - 1]->isIndexed())
{
++numIndexed;
arguments[arg - 1]->accept(*this);
appendTypeConversion(*arguments[arg - 1]->getType(),
*function.getParameterTypes()[arg - 1], true);
}
m_context << u256(h256::Arith(dev::sha3(function.getCanonicalSignature(event.getName()))));
++numIndexed;
solAssert(numIndexed <= 4, "Too many indexed arguments.");
// Copy all non-indexed arguments to memory (data)
m_context << u256(0);
for (unsigned arg = 0; arg < arguments.size(); ++arg)
if (!event.getParameters()[arg]->isIndexed())
appendExpressionCopyToMemory(*function.getParameterTypes()[arg], *arguments[arg]);
m_context << u256(0) << eth::logInstruction(numIndexed);
break;
}
case Location::BlockHash:
{
arguments[0]->accept(*this);
appendTypeConversion(*arguments[0]->getType(), *function.getParameterTypes()[0], true);
m_context << eth::Instruction::BLOCKHASH;
break;
}
case Location::ECRecover:
case Location::SHA256:
case Location::RIPEMD160:
{
_functionCall.getExpression().accept(*this);
static const map<Location, u256> contractAddresses{{Location::ECRecover, 1},
{Location::SHA256, 2},
{Location::RIPEMD160, 3}};
m_context << contractAddresses.find(function.getLocation())->second;
for (unsigned i = function.getSizeOnStack(); i > 0; --i)
m_context << eth::swapInstruction(i);
appendExternalFunctionCall(function, arguments, true);
break;
}
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid function type."));
}
}
return false;
}
bool ExpressionCompiler::visit(NewExpression const&)
{
// code is created for the function call (CREATION) only
return false;
}
void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
{
CompilerContext::LocationSetter locationSetter(m_context, _memberAccess);
ASTString const& member = _memberAccess.getMemberName();
switch (_memberAccess.getExpression().getType()->getCategory())
{
case Type::Category::Contract:
{
bool alsoSearchInteger = false;
ContractType const& type = dynamic_cast<ContractType const&>(*_memberAccess.getExpression().getType());
if (type.isSuper())
m_context << m_context.getSuperFunctionEntryLabel(member, type.getContractDefinition()).pushTag();
else
{
// ordinary contract type
u256 identifier = type.getFunctionIdentifier(member);
if (identifier != Invalid256)
{
appendTypeConversion(type, IntegerType(0, IntegerType::Modifier::Address), true);
m_context << identifier;
}
else
// not found in contract, search in members inherited from address
alsoSearchInteger = true;
}
if (!alsoSearchInteger)
break;
}
case Type::Category::Integer:
if (member == "balance")
{
appendTypeConversion(*_memberAccess.getExpression().getType(),
IntegerType(0, IntegerType::Modifier::Address), true);
m_context << eth::Instruction::BALANCE;
}
else if (member == "send" || member.substr(0, min<size_t>(member.size(), 4)) == "call")
appendTypeConversion(*_memberAccess.getExpression().getType(),
IntegerType(0, IntegerType::Modifier::Address), true);
else
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid member access to integer."));
break;
case Type::Category::Function:
solAssert(!!_memberAccess.getExpression().getType()->getMemberType(member),
"Invalid member access to function.");
break;
case Type::Category::Magic:
// we can ignore the kind of magic and only look at the name of the member
if (member == "coinbase")
m_context << eth::Instruction::COINBASE;
else if (member == "timestamp")
m_context << eth::Instruction::TIMESTAMP;
else if (member == "difficulty")
m_context << eth::Instruction::DIFFICULTY;
else if (member == "number")
m_context << eth::Instruction::NUMBER;
else if (member == "gaslimit")
m_context << eth::Instruction::GASLIMIT;
else if (member == "sender")
m_context << eth::Instruction::CALLER;
else if (member == "value")
m_context << eth::Instruction::CALLVALUE;
else if (member == "origin")
m_context << eth::Instruction::ORIGIN;
else if (member == "gas")
m_context << eth::Instruction::GAS;
else if (member == "gasprice")
m_context << eth::Instruction::GASPRICE;
else if (member == "data")
m_context << u256(0) << eth::Instruction::CALLDATASIZE;
else if (member == "sig")
m_context << u256(0) << eth::Instruction::CALLDATALOAD
<< (u256(0xffffffff) << (256 - 32)) << eth::Instruction::AND;
else
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown magic member."));
break;
case Type::Category::Struct:
{
StructType const& type = dynamic_cast<StructType const&>(*_memberAccess.getExpression().getType());
m_context << eth::Instruction::POP; // structs always align to new slot
pair<u256, unsigned> const& offsets = type.getStorageOffsetsOfMember(member);
m_context << offsets.first << eth::Instruction::ADD << u256(offsets.second);
setLValueToStorageItem(_memberAccess);
break;
}
case Type::Category::Enum:
{
EnumType const& type = dynamic_cast<EnumType const&>(*_memberAccess.getExpression().getType());
m_context << type.getMemberValue(_memberAccess.getMemberName());
break;
}
case Type::Category::TypeType:
{
TypeType const& type = dynamic_cast<TypeType const&>(*_memberAccess.getExpression().getType());
if (!type.getMembers().getMemberType(member))
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid member access to " + type.toString()));
if (auto contractType = dynamic_cast<ContractType const*>(type.getActualType().get()))
{
ContractDefinition const& contract = contractType->getContractDefinition();
for (ASTPointer<FunctionDefinition> const& function: contract.getDefinedFunctions())
if (function->getName() == member)
{
m_context << m_context.getFunctionEntryLabel(*function).pushTag();
return;
}
solAssert(false, "Function not found in member access.");
}
else if (auto enumType = dynamic_cast<EnumType const*>(type.getActualType().get()))
m_context << enumType->getMemberValue(_memberAccess.getMemberName());
break;
}
case Type::Category::Array:
{
solAssert(member == "length", "Illegal array member.");
auto const& type = dynamic_cast<ArrayType const&>(*_memberAccess.getExpression().getType());
if (!type.isDynamicallySized())
{
CompilerUtils(m_context).popStackElement(type);
m_context << type.getLength();
}
else
switch (type.getLocation())
{
case ArrayType::Location::CallData:
m_context << eth::Instruction::SWAP1 << eth::Instruction::POP;
break;
case ArrayType::Location::Storage:
setLValue<StorageArrayLength>(_memberAccess, type);
break;
default:
solAssert(false, "Unsupported array location.");
break;
}
break;
}
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Member access to unknown type."));
}
}
bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
{
CompilerContext::LocationSetter locationSetter(m_context, _indexAccess);
_indexAccess.getBaseExpression().accept(*this);
Type const& baseType = *_indexAccess.getBaseExpression().getType();
if (baseType.getCategory() == Type::Category::Mapping)
{
// storage byte offset is ignored for mappings, it should be zero.
m_context << eth::Instruction::POP;
// stack: storage_base_ref
Type const& keyType = *dynamic_cast<MappingType const&>(baseType).getKeyType();
m_context << u256(0); // memory position
solAssert(_indexAccess.getIndexExpression(), "Index expression expected.");
appendExpressionCopyToMemory(keyType, *_indexAccess.getIndexExpression());
m_context << eth::Instruction::SWAP1;
appendTypeMoveToMemory(IntegerType(256));
m_context << u256(0) << eth::Instruction::SHA3;
m_context << u256(0);
setLValueToStorageItem( _indexAccess);
}
else if (baseType.getCategory() == Type::Category::Array)
{
// stack layout: <base_ref> [storage_byte_offset] [<length>] <index>
ArrayType const& arrayType = dynamic_cast<ArrayType const&>(baseType);
solAssert(_indexAccess.getIndexExpression(), "Index expression expected.");
ArrayType::Location location = arrayType.getLocation();
eth::Instruction load =
location == ArrayType::Location::Storage ? eth::Instruction::SLOAD :
location == ArrayType::Location::Memory ? eth::Instruction::MLOAD :
eth::Instruction::CALLDATALOAD;
_indexAccess.getIndexExpression()->accept(*this);
// retrieve length
if (!arrayType.isDynamicallySized())
m_context << arrayType.getLength();
else if (location == ArrayType::Location::CallData)
// length is stored on the stack
m_context << eth::Instruction::SWAP1;
else if (location == ArrayType::Location::Storage)
m_context << eth::Instruction::DUP3 << load;
else
m_context << eth::Instruction::DUP2 << load;
// stack: <base_ref> [storage_byte_offset] <index> <length>
// check out-of-bounds access
m_context << eth::Instruction::DUP2 << eth::Instruction::LT;
eth::AssemblyItem legalAccess = m_context.appendConditionalJump();
// out-of-bounds access throws exception (just STOP for now)
m_context << eth::Instruction::STOP;
m_context << legalAccess;
// stack: <base_ref> [storage_byte_offset] <index>
if (arrayType.isByteArray())
// byte array is packed differently, especially in storage
switch (location)
{
case ArrayType::Location::Storage:
// byte array index storage lvalue on stack (goal):
// <ref> <byte_number> = <base_ref + index / 32> <index % 32>
m_context << u256(32) << eth::Instruction::SWAP3;
CompilerUtils(m_context).computeHashStatic();
// stack: 32 storage_byte_offset index data_ref
m_context
<< eth::Instruction::DUP4 << eth::Instruction::DUP3
<< eth::Instruction::DIV << eth::Instruction::ADD
// stack: 32 storage_byte_offset index (data_ref + index / 32)
<< eth::Instruction::SWAP3 << eth::Instruction::SWAP2
<< eth::Instruction::POP << eth::Instruction::MOD;
setLValue<StorageByteArrayElement>(_indexAccess);
break;
case ArrayType::Location::CallData:
// no lvalue, just retrieve the value
m_context
<< eth::Instruction::ADD << eth::Instruction::CALLDATALOAD
<< ((u256(0xff) << (256 - 8))) << eth::Instruction::AND;
break;
case ArrayType::Location::Memory:
solAssert(false, "Memory lvalues not yet implemented.");
}
else
{
// stack: <base_ref> [storage_byte_offset] <index>
if (location == ArrayType::Location::Storage)
//@todo use byte offset, remove it for now
m_context << eth::Instruction::SWAP1 << eth::Instruction::POP;
u256 elementSize =
location == ArrayType::Location::Storage ?
arrayType.getBaseType()->getStorageSize() :
arrayType.getBaseType()->getCalldataEncodedSize();
solAssert(elementSize != 0, "Invalid element size.");
if (elementSize > 1)
m_context << elementSize << eth::Instruction::MUL;
if (arrayType.isDynamicallySized())
{
if (location == ArrayType::Location::Storage)
{
m_context << eth::Instruction::SWAP1;
CompilerUtils(m_context).computeHashStatic();
}
else if (location == ArrayType::Location::Memory)
m_context << u256(32) << eth::Instruction::ADD;
}
m_context << eth::Instruction::ADD;
switch (location)
{
case ArrayType::Location::CallData:
if (arrayType.getBaseType()->isValueType())
CompilerUtils(m_context).loadFromMemoryDynamic(*arrayType.getBaseType(), true, true, false);
break;
case ArrayType::Location::Storage:
m_context << u256(0); // @todo
setLValueToStorageItem(_indexAccess);
break;
case ArrayType::Location::Memory:
solAssert(false, "Memory lvalues not yet implemented.");
}
}
}
else
solAssert(false, "Index access only allowed for mappings or arrays.");
return false;
}
void ExpressionCompiler::endVisit(Identifier const& _identifier)
{
CompilerContext::LocationSetter locationSetter(m_context, _identifier);
Declaration const* declaration = _identifier.getReferencedDeclaration();
if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
{
switch (magicVar->getType()->getCategory())
{
case Type::Category::Contract:
// "this" or "super"
if (!dynamic_cast<ContractType const&>(*magicVar->getType()).isSuper())
m_context << eth::Instruction::ADDRESS;
break;
case Type::Category::Integer:
// "now"
m_context << eth::Instruction::TIMESTAMP;
break;
default:
break;
}
}
else if (FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(declaration))
m_context << m_context.getVirtualFunctionEntryLabel(*functionDef).pushTag();
else if (auto variable = dynamic_cast<VariableDeclaration const*>(declaration))
{
if (!variable->isConstant())
setLValueFromDeclaration(*declaration, _identifier);
else
variable->getValue()->accept(*this);
}
else if (dynamic_cast<ContractDefinition const*>(declaration))
{
// no-op
}
else if (dynamic_cast<EventDefinition const*>(declaration))
{
// no-op
}
else if (dynamic_cast<EnumDefinition const*>(declaration))
{
// no-op
}
else
{
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Identifier type not expected in expression context."));
}
}
void ExpressionCompiler::endVisit(Literal const& _literal)
{
CompilerContext::LocationSetter locationSetter(m_context, _literal);
switch (_literal.getType()->getCategory())
{
case Type::Category::IntegerConstant:
case Type::Category::Bool:
case Type::Category::FixedBytes:
m_context << _literal.getType()->literalValue(&_literal);
break;
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Only integer, boolean and string literals implemented for now."));
}
}
void ExpressionCompiler::appendAndOrOperatorCode(BinaryOperation const& _binaryOperation)
{
Token::Value const c_op = _binaryOperation.getOperator();
solAssert(c_op == Token::Or || c_op == Token::And, "");
_binaryOperation.getLeftExpression().accept(*this);
m_context << eth::Instruction::DUP1;
if (c_op == Token::And)
m_context << eth::Instruction::ISZERO;
eth::AssemblyItem endLabel = m_context.appendConditionalJump();
m_context << eth::Instruction::POP;
_binaryOperation.getRightExpression().accept(*this);
m_context << endLabel;
}
void ExpressionCompiler::appendCompareOperatorCode(Token::Value _operator, Type const& _type)
{
if (_operator == Token::Equal || _operator == Token::NotEqual)
{
m_context << eth::Instruction::EQ;
if (_operator == Token::NotEqual)
m_context << eth::Instruction::ISZERO;
}
else
{
IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
bool const c_isSigned = type.isSigned();
switch (_operator)
{
case Token::GreaterThanOrEqual:
m_context << (c_isSigned ? eth::Instruction::SLT : eth::Instruction::LT)
<< eth::Instruction::ISZERO;
break;
case Token::LessThanOrEqual:
m_context << (c_isSigned ? eth::Instruction::SGT : eth::Instruction::GT)
<< eth::Instruction::ISZERO;
break;
case Token::GreaterThan:
m_context << (c_isSigned ? eth::Instruction::SGT : eth::Instruction::GT);
break;
case Token::LessThan:
m_context << (c_isSigned ? eth::Instruction::SLT : eth::Instruction::LT);
break;
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown comparison operator."));
}
}
}
void ExpressionCompiler::appendOrdinaryBinaryOperatorCode(Token::Value _operator, Type const& _type)
{
if (Token::isArithmeticOp(_operator))
appendArithmeticOperatorCode(_operator, _type);
else if (Token::isBitOp(_operator))
appendBitOperatorCode(_operator);
else if (Token::isShiftOp(_operator))
appendShiftOperatorCode(_operator);
else
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown binary operator."));
}
void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Type const& _type)
{
IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
bool const c_isSigned = type.isSigned();
switch (_operator)
{
case Token::Add:
m_context << eth::Instruction::ADD;
break;
case Token::Sub:
m_context << eth::Instruction::SUB;
break;
case Token::Mul:
m_context << eth::Instruction::MUL;
break;
case Token::Div:
m_context << (c_isSigned ? eth::Instruction::SDIV : eth::Instruction::DIV);
break;
case Token::Mod:
m_context << (c_isSigned ? eth::Instruction::SMOD : eth::Instruction::MOD);
break;
case Token::Exp:
m_context << eth::Instruction::EXP;
break;
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown arithmetic operator."));
}
}
void ExpressionCompiler::appendBitOperatorCode(Token::Value _operator)
{
switch (_operator)
{
case Token::BitOr:
m_context << eth::Instruction::OR;
break;
case Token::BitAnd:
m_context << eth::Instruction::AND;
break;
case Token::BitXor:
m_context << eth::Instruction::XOR;
break;
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown bit operator."));
}
}
void ExpressionCompiler::appendShiftOperatorCode(Token::Value _operator)
{
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Shift operators not yet implemented."));
switch (_operator)
{
case Token::SHL:
break;
case Token::SAR:
break;
default:
BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown shift operator."));
}
}
void ExpressionCompiler::appendHighBitsCleanup(IntegerType const& _typeOnStack)
{
if (_typeOnStack.getNumBits() == 256)
return;
else if (_typeOnStack.isSigned())
m_context << u256(_typeOnStack.getNumBits() / 8 - 1) << eth::Instruction::SIGNEXTEND;
else
m_context << ((u256(1) << _typeOnStack.getNumBits()) - 1) << eth::Instruction::AND;
}
void ExpressionCompiler::appendExternalFunctionCall(FunctionType const& _functionType,
vector<ASTPointer<Expression const>> const& _arguments,
bool bare)
{
solAssert(_functionType.takesArbitraryParameters() ||
_arguments.size() == _functionType.getParameterTypes().size(), "");
// Assumed stack content here:
// <stack top>
// value [if _functionType.valueSet()]
// gas [if _functionType.gasSet()]
// function identifier [unless bare]
// contract address
unsigned gasValueSize = (_functionType.gasSet() ? 1 : 0) + (_functionType.valueSet() ? 1 : 0);
unsigned contractStackPos = m_context.currentToBaseStackOffset(1 + gasValueSize + (bare ? 0 : 1));
unsigned gasStackPos = m_context.currentToBaseStackOffset(gasValueSize);
unsigned valueStackPos = m_context.currentToBaseStackOffset(1);
//@todo only return the first return value for now
Type const* firstType = _functionType.getReturnParameterTypes().empty() ? nullptr :
_functionType.getReturnParameterTypes().front().get();
unsigned retSize = firstType ? firstType->getCalldataEncodedSize() : 0;
m_context << u256(retSize) << u256(0);
if (bare)
m_context << u256(0);
else
{
// copy function identifier
m_context << eth::dupInstruction(gasValueSize + 3);
CompilerUtils(m_context).storeInMemory(0, IntegerType(CompilerUtils::dataStartOffset * 8));
m_context << u256(CompilerUtils::dataStartOffset);
}
// For bare call, activate "4 byte pad exception": If the first argument has exactly 4 bytes,
// do not pad it to 32 bytes.
appendArgumentsCopyToMemory(_arguments, _functionType.getParameterTypes(),
_functionType.padArguments(), bare);
// CALL arguments: outSize, outOff, inSize, (already present up to here)
// inOff, value, addr, gas (stack top)
m_context << u256(0);
if (_functionType.valueSet())
m_context << eth::dupInstruction(m_context.baseToCurrentStackOffset(valueStackPos));
else
m_context << u256(0);
m_context << eth::dupInstruction(m_context.baseToCurrentStackOffset(contractStackPos));
if (_functionType.gasSet())
m_context << eth::dupInstruction(m_context.baseToCurrentStackOffset(gasStackPos));
else
// send all gas except the amount needed to execute "SUB" and "CALL"
// @todo this retains too much gas for now, needs to be fine-tuned.
m_context << u256(50 + (_functionType.valueSet() ? 9000 : 0)) << eth::Instruction::GAS << eth::Instruction::SUB;
m_context << eth::Instruction::CALL;
auto tag = m_context.appendConditionalJump();
m_context << eth::Instruction::STOP << tag; // STOP if CALL leaves 0.
if (_functionType.valueSet())
m_context << eth::Instruction::POP;
if (_functionType.gasSet())
m_context << eth::Instruction::POP;
if (!bare)
m_context << eth::Instruction::POP;
m_context << eth::Instruction::POP; // pop contract address
if (firstType)
CompilerUtils(m_context).loadFromMemory(0, *firstType, false, true);
}
void ExpressionCompiler::appendArgumentsCopyToMemory(
vector<ASTPointer<Expression const>> const& _arguments,
TypePointers const& _types,
bool _padToWordBoundaries,
bool _padExceptionIfFourBytes
)
{
solAssert(_types.empty() || _types.size() == _arguments.size(), "");
for (size_t i = 0; i < _arguments.size(); ++i)
{
_arguments[i]->accept(*this);
TypePointer const& expectedType = _types.empty() ? _arguments[i]->getType()->getRealType() : _types[i];
appendTypeConversion(*_arguments[i]->getType(), *expectedType, true);
bool pad = _padToWordBoundaries;
// Do not pad if the first argument has exactly four bytes
if (i == 0 && pad && _padExceptionIfFourBytes && expectedType->getCalldataEncodedSize(false) == 4)
pad = false;
appendTypeMoveToMemory(*expectedType, pad);
}
}
void ExpressionCompiler::appendTypeMoveToMemory(Type const& _type, bool _padToWordBoundaries)
{
CompilerUtils(m_context).storeInMemoryDynamic(_type, _padToWordBoundaries);
}
void ExpressionCompiler::appendExpressionCopyToMemory(Type const& _expectedType, Expression const& _expression)
{
_expression.accept(*this);
appendTypeConversion(*_expression.getType(), _expectedType, true);
appendTypeMoveToMemory(_expectedType);
}
void ExpressionCompiler::setLValueFromDeclaration(Declaration const& _declaration, Expression const& _expression)
{
if (m_context.isLocalVariable(&_declaration))
setLValue<StackVariable>(_expression, _declaration);
else if (m_context.isStateVariable(&_declaration))
setLValue<StorageItem>(_expression, _declaration);
else
BOOST_THROW_EXCEPTION(InternalCompilerError()
<< errinfo_sourceLocation(_expression.getLocation())
<< errinfo_comment("Identifier type not supported or identifier not found."));
}
void ExpressionCompiler::setLValueToStorageItem(Expression const& _expression)
{
setLValue<StorageItem>(_expression, *_expression.getType());
}
}
}