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/*
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 <libdevcore/Common.h>
#include <libsolidity/ASTVisitor.h>
namespace dev {
namespace eth
{
class AssemblyItem; // forward
}
namespace solidity {
class CompilerContext; // forward
class Type; // forward
class IntegerType; // forward
/**
* Compiler for expressions, i.e. converts an AST tree whose root is an Expression into a stream
* of EVM instructions. It needs a compiler context that is the same for the whole compilation
* unit.
*/
class ExpressionCompiler: private ASTVisitor
{
public:
/// Compile the given @a _expression into the @a _context.
static void compileExpression(CompilerContext& _context, Expression& _expression);
/// Appends code to remove dirty higher order bits in case of an implicit promotion to a wider type.
static void appendTypeConversion(CompilerContext& _context, Type const& _typeOnStack, Type const& _targetType);
private:
ExpressionCompiler(CompilerContext& _compilerContext): m_context(_compilerContext) {}
virtual bool visit(Assignment& _assignment) override;
virtual void endVisit(UnaryOperation& _unaryOperation) override;
virtual bool visit(BinaryOperation& _binaryOperation) override;
virtual bool visit(FunctionCall& _functionCall) override;
virtual void endVisit(MemberAccess& _memberAccess) override;
virtual void endVisit(IndexAccess& _indexAccess) override;
virtual void endVisit(Identifier& _identifier) override;
virtual void endVisit(Literal& _literal) override;
///@{
///@name Append code for various operator types
void appendAndOrOperatorCode(BinaryOperation& _binaryOperation);
void appendCompareOperatorCode(Token::Value _operator, Type const& _type);
void appendOrdinaryBinaryOperatorCode(Token::Value _operator, Type const& _type);
void appendArithmeticOperatorCode(Token::Value _operator, Type const& _type);
void appendBitOperatorCode(Token::Value _operator);
void appendShiftOperatorCode(Token::Value _operator);
/// @}
/// Appends an implicit or explicit type conversion. For now this comprises only erasing
/// higher-order bits (@see appendHighBitCleanup) when widening integer types.
/// If @a _cleanupNeeded, high order bits cleanup is also done if no type conversion would be
/// necessary.
void appendTypeConversion(Type const& _typeOnStack, Type const& _targetType, bool _cleanupNeeded = false);
//// Appends code that cleans higher-order bits for integer types.
void appendHighBitsCleanup(IntegerType const& _typeOnStack);
/// Copies the value of the current lvalue to the top of the stack.
void retrieveLValueValue(Expression const& _expression);
/// Stores the value on top of the stack in the current lvalue. Removes it from the stack if
/// @a _move is true.
void storeInLValue(Expression const& _expression, bool _move = false);
/**
* Location of an lvalue, either in code (for a function) on the stack, in the storage or memory.
*/
struct LValueLocation
{
enum LocationType { INVALID, CODE, STACK, MEMORY, STORAGE };
LValueLocation() { reset(); }
LValueLocation(LocationType _type, u256 const& _location): locationType(_type), location(_location) {}
void reset() { locationType = INVALID; location = 0; }
bool isValid() const { return locationType != INVALID; }
bool isInCode() const { return locationType == CODE; }
bool isInOnStack() const { return locationType == STACK; }
bool isInMemory() const { return locationType == MEMORY; }
bool isInStorage() const { return locationType == STORAGE; }
LocationType locationType;
/// Depending on the type, this is the id of a tag (code), the base offset of a stack
/// variable (@see CompilerContext::getBaseStackOffsetOfVariable) or the offset in
/// storage or memory.
u256 location;
};
LValueLocation m_currentLValue;
CompilerContext& m_context;
};
}
}
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