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Diffstat (limited to 'Compiler.cpp')
| -rw-r--r-- | Compiler.cpp | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/Compiler.cpp b/Compiler.cpp new file mode 100644 index 00000000..319f9b1c --- /dev/null +++ b/Compiler.cpp @@ -0,0 +1,408 @@ +/* + 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. + */ + +#include <boost/assert.hpp> +#include <utility> +#include <libsolidity/AST.h> +#include <libsolidity/Compiler.h> + + +namespace dev { +namespace solidity { + + +void CompilerContext::setLabelPosition(uint32_t _label, uint32_t _position) +{ + BOOST_ASSERT(m_labelPositions.find(_label) == m_labelPositions.end()); + m_labelPositions[_label] = _position; +} + +uint32_t CompilerContext::getLabelPosition(uint32_t _label) const +{ + auto iter = m_labelPositions.find(_label); + BOOST_ASSERT(iter != m_labelPositions.end()); + return iter->second; +} + +void ExpressionCompiler::compile(Expression& _expression) +{ + m_assemblyItems.clear(); + _expression.accept(*this); +} + +bytes ExpressionCompiler::getAssembledBytecode() const +{ + bytes assembled; + assembled.reserve(m_assemblyItems.size()); + + // resolve label references + for (uint32_t pos = 0; pos < m_assemblyItems.size(); ++pos) + { + AssemblyItem const& item = m_assemblyItems[pos]; + if (item.getType() == AssemblyItem::Type::LABEL) + m_context.setLabelPosition(item.getLabel(), pos + 1); + } + + for (AssemblyItem const& item: m_assemblyItems) + { + if (item.getType() == AssemblyItem::Type::LABELREF) + assembled.push_back(m_context.getLabelPosition(item.getLabel())); + else + assembled.push_back(item.getData()); + } + + return assembled; +} + +AssemblyItems ExpressionCompiler::compileExpression(CompilerContext& _context, + Expression& _expression) +{ + ExpressionCompiler compiler(_context); + compiler.compile(_expression); + return compiler.getAssemblyItems(); +} + +void ExpressionCompiler::endVisit(Assignment& _assignment) +{ + Expression& rightHandSide = _assignment.getRightHandSide(); + Token::Value op = _assignment.getAssignmentOperator(); + if (op != Token::ASSIGN) + { + // compound assignment + // @todo retrieve lvalue value + rightHandSide.accept(*this); + Type const& resultType = *_assignment.getType(); + cleanHigherOrderBitsIfNeeded(*rightHandSide.getType(), resultType); + appendOrdinaryBinaryOperatorCode(Token::AssignmentToBinaryOp(op), resultType); + } + else + rightHandSide.accept(*this); + // @todo store value +} + +void ExpressionCompiler::endVisit(UnaryOperation& _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 + switch (_unaryOperation.getOperator()) + { + case Token::NOT: // ! + append(eth::Instruction::NOT); + break; + case Token::BIT_NOT: // ~ + // ~a modeled as "a xor (0 - 1)" for now + append(eth::Instruction::PUSH1); + append(1); + append(eth::Instruction::PUSH1); + append(0); + append(eth::Instruction::SUB); + append(eth::Instruction::XOR); + break; + case Token::DELETE: // delete + // a -> a xor a (= 0). + // @todo this should also be an assignment + // @todo semantics change for complex types + append(eth::Instruction::DUP1); + append(eth::Instruction::XOR); + break; + case Token::INC: // ++ (pre- or postfix) + // @todo this should also be an assignment + if (_unaryOperation.isPrefixOperation()) + { + append(eth::Instruction::PUSH1); + append(1); + append(eth::Instruction::ADD); + } + break; + case Token::DEC: // -- (pre- or postfix) + // @todo this should also be an assignment + if (_unaryOperation.isPrefixOperation()) + { + append(eth::Instruction::PUSH1); + append(1); + append(eth::Instruction::SWAP1); //@todo avoid this + append(eth::Instruction::SUB); + } + break; + case Token::ADD: // + + // unary add, so basically no-op + break; + case Token::SUB: // - + append(eth::Instruction::NEG); + break; + default: + BOOST_ASSERT(false); // invalid operation + } +} + +bool ExpressionCompiler::visit(BinaryOperation& _binaryOperation) +{ + Expression& leftExpression = _binaryOperation.getLeftExpression(); + Expression& rightExpression = _binaryOperation.getRightExpression(); + Type const& resultType = *_binaryOperation.getType(); + Token::Value const op = _binaryOperation.getOperator(); + + if (op == Token::AND || op == Token::OR) + { + // special case: short-circuiting + appendAndOrOperatorCode(_binaryOperation); + } + else if (Token::isCompareOp(op)) + { + leftExpression.accept(*this); + rightExpression.accept(*this); + + // the types to compare have to be the same, but the resulting type is always bool + BOOST_ASSERT(*leftExpression.getType() == *rightExpression.getType()); + appendCompareOperatorCode(op, *leftExpression.getType()); + } + else + { + leftExpression.accept(*this); + cleanHigherOrderBitsIfNeeded(*leftExpression.getType(), resultType); + rightExpression.accept(*this); + cleanHigherOrderBitsIfNeeded(*rightExpression.getType(), resultType); + appendOrdinaryBinaryOperatorCode(op, resultType); + } + + // do not visit the child nodes, we already did that explicitly + return false; +} + +void ExpressionCompiler::endVisit(FunctionCall& _functionCall) +{ + if (_functionCall.isTypeConversion()) + { + //@todo binary representation for all supported types (bool and int) is the same, so no-op + // here for now. + } + else + { + //@todo + } +} + +void ExpressionCompiler::endVisit(MemberAccess& _memberAccess) +{ + +} + +void ExpressionCompiler::endVisit(IndexAccess& _indexAccess) +{ + +} + +void ExpressionCompiler::endVisit(Identifier& _identifier) +{ + +} + +void ExpressionCompiler::endVisit(Literal& _literal) +{ + switch (_literal.getType()->getCategory()) + { + case Type::Category::INTEGER: + case Type::Category::BOOL: + { + bytes value = _literal.getType()->literalToBigEndian(_literal); + BOOST_ASSERT(value.size() <= 32); + BOOST_ASSERT(!value.empty()); + append(static_cast<byte>(eth::Instruction::PUSH1) + static_cast<byte>(value.size() - 1)); + append(value); + break; + } + default: + BOOST_ASSERT(false); // @todo + } +} + +void ExpressionCompiler::cleanHigherOrderBitsIfNeeded(const Type& _typeOnStack, const Type& _targetType) +{ + // If the type of one of the operands is extended, 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) + return; + if (_typeOnStack.getCategory() == Type::Category::INTEGER && + _targetType.getCategory() == Type::Category::INTEGER) + { + //@todo + } + else + { + // If we get here, there is either an implementation missing to clean higher oder bits + // for non-integer types that are explicitly convertible or we got here in error. + BOOST_ASSERT(!_typeOnStack.isExplicitlyConvertibleTo(_targetType)); + BOOST_ASSERT(false); // these types should not be convertible. + } +} + +void ExpressionCompiler::appendAndOrOperatorCode(BinaryOperation& _binaryOperation) +{ + Token::Value const op = _binaryOperation.getOperator(); + BOOST_ASSERT(op == Token::OR || op == Token::AND); + + _binaryOperation.getLeftExpression().accept(*this); + append(eth::Instruction::DUP1); + if (op == Token::AND) + append(eth::Instruction::NOT); + uint32_t endLabel = appendConditionalJump(); + _binaryOperation.getRightExpression().accept(*this); + appendLabel(endLabel); +} + +void ExpressionCompiler::appendCompareOperatorCode(Token::Value _operator, Type const& _type) +{ + if (_operator == Token::EQ || _operator == Token::NE) + { + append(eth::Instruction::EQ); + if (_operator == Token::NE) + append(eth::Instruction::NOT); + } + else + { + IntegerType const* type = dynamic_cast<IntegerType const*>(&_type); + BOOST_ASSERT(type != nullptr); + bool const isSigned = type->isSigned(); + + // note that EVM opcodes compare like "stack[0] < stack[1]", + // but our left value is at stack[1], so everyhing is reversed. + switch (_operator) + { + case Token::GTE: + append(isSigned ? eth::Instruction::SGT : eth::Instruction::GT); + append(eth::Instruction::NOT); + break; + case Token::LTE: + append(isSigned ? eth::Instruction::SLT : eth::Instruction::LT); + append(eth::Instruction::NOT); + break; + case Token::GT: + append(isSigned ? eth::Instruction::SLT : eth::Instruction::LT); + break; + case Token::LT: + append(isSigned ? eth::Instruction::SGT : eth::Instruction::GT); + break; + default: + BOOST_ASSERT(false); + } + } +} + +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_ASSERT(false); // unknown binary operator +} + +void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Type const& _type) +{ + IntegerType const* type = dynamic_cast<IntegerType const*>(&_type); + BOOST_ASSERT(type != nullptr); + bool const isSigned = type->isSigned(); + + switch (_operator) + { + case Token::ADD: + append(eth::Instruction::ADD); + break; + case Token::SUB: + append(eth::Instruction::SWAP1); + append(eth::Instruction::SUB); + break; + case Token::MUL: + append(eth::Instruction::MUL); + break; + case Token::DIV: + append(isSigned ? eth::Instruction::SDIV : eth::Instruction::DIV); + break; + case Token::MOD: + append(isSigned ? eth::Instruction::SMOD : eth::Instruction::MOD); + break; + default: + BOOST_ASSERT(false); + } +} + +void ExpressionCompiler::appendBitOperatorCode(Token::Value _operator) +{ + switch (_operator) + { + case Token::BIT_OR: + append(eth::Instruction::OR); + break; + case Token::BIT_AND: + append(eth::Instruction::AND); + break; + case Token::BIT_XOR: + append(eth::Instruction::XOR); + break; + default: + BOOST_ASSERT(false); + } +} + +void ExpressionCompiler::appendShiftOperatorCode(Token::Value _operator) +{ + switch (_operator) + { + case Token::SHL: + BOOST_ASSERT(false); //@todo + break; + case Token::SAR: + BOOST_ASSERT(false); //@todo + break; + default: + BOOST_ASSERT(false); + } +} + +uint32_t ExpressionCompiler::appendConditionalJump() +{ + uint32_t label = m_context.dispenseNewLabel(); + append(eth::Instruction::PUSH1); + appendLabelref(label); + append(eth::Instruction::JUMPI); + return label; +} + +void ExpressionCompiler::append(bytes const& _data) +{ + m_assemblyItems.reserve(m_assemblyItems.size() + _data.size()); + for (byte b: _data) + append(b); +} + + + +} +} |