/*
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 compiler.
*/
#include <algorithm>
#include <libevmcore/Instruction.h>
#include <libevmcore/Assembly.h>
#include <libsolidity/AST.h>
#include <libsolidity/Compiler.h>
#include <libsolidity/ExpressionCompiler.h>
using namespace std;
namespace dev {
namespace solidity {
void Compiler::compileContract(ContractDefinition& _contract, vector<MagicVariableDeclaration const*> const& _magicGlobals)
{
m_context = CompilerContext(); // clear it just in case
for (MagicVariableDeclaration const* variable: _magicGlobals)
m_context.addMagicGlobal(*variable);
for (ASTPointer<FunctionDefinition> const& function: _contract.getDefinedFunctions())
if (function->getName() != _contract.getName()) // don't add the constructor here
m_context.addFunction(*function);
registerStateVariables(_contract);
appendFunctionSelector(_contract);
for (ASTPointer<FunctionDefinition> const& function: _contract.getDefinedFunctions())
if (function->getName() != _contract.getName()) // don't add the constructor here
function->accept(*this);
packIntoContractCreator(_contract);
}
void Compiler::packIntoContractCreator(ContractDefinition const& _contract)
{
CompilerContext runtimeContext;
swap(m_context, runtimeContext);
registerStateVariables(_contract);
FunctionDefinition* constructor = nullptr;
for (ASTPointer<FunctionDefinition> const& function: _contract.getDefinedFunctions())
if (function->getName() == _contract.getName())
{
constructor = function.get();
break;
}
if (constructor)
{
eth::AssemblyItem returnTag = m_context.pushNewTag();
m_context.addFunction(*constructor); // note that it cannot be called due to syntactic reasons
//@todo copy constructor arguments from calldata to memory prior to this
//@todo calling other functions inside the constructor should either trigger a parse error
//or we should copy them here (register them above and call "accept") - detecting which
// functions are referenced / called needs to be done in a recursive way.
appendCalldataUnpacker(*constructor, true);
m_context.appendJumpTo(m_context.getFunctionEntryLabel(*constructor));
constructor->accept(*this);
m_context << returnTag;
}
eth::AssemblyItem sub = m_context.addSubroutine(runtimeContext.getAssembly());
// stack contains sub size
m_context << eth::Instruction::DUP1 << sub << u256(0) << eth::Instruction::CODECOPY;
m_context << u256(0) << eth::Instruction::RETURN;
}
void Compiler::appendFunctionSelector(ContractDefinition const& _contract)
{
vector<FunctionDefinition const*> interfaceFunctions = _contract.getInterfaceFunctions();
vector<eth::AssemblyItem> callDataUnpackerEntryPoints;
if (interfaceFunctions.size() > 255)
BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("More than 255 public functions for contract."));
// retrieve the first byte of the call data, which determines the called function
// @todo This code had a jump table in a previous version which was more efficient but also
// error prone (due to the optimizer and variable length tag addresses)
m_context << u256(1) << u256(0) // some constants
<< eth::dupInstruction(1) << eth::Instruction::CALLDATALOAD
<< eth::dupInstruction(2) << eth::Instruction::BYTE
<< eth::dupInstruction(2);
// stack here: 1 0 <funid> 0, stack top will be counted up until it matches funid
for (unsigned funid = 0; funid < interfaceFunctions.size(); ++funid)
{
callDataUnpackerEntryPoints.push_back(m_context.newTag());
m_context << eth::dupInstruction(2) << eth::dupInstruction(2) << eth::Instruction::EQ;
m_context.appendConditionalJumpTo(callDataUnpackerEntryPoints.back());
m_context << eth::dupInstruction(4) << eth::Instruction::ADD;
//@todo avoid the last ADD (or remove it in the optimizer)
}
m_context << eth::Instruction::STOP; // function not found
for (unsigned funid = 0; funid < interfaceFunctions.size(); ++funid)
{
FunctionDefinition const& function = *interfaceFunctions[funid];
m_context << callDataUnpackerEntryPoints[funid];
eth::AssemblyItem returnTag = m_context.pushNewTag();
appendCalldataUnpacker(function);
m_context.appendJumpTo(m_context.getFunctionEntryLabel(function));
m_context << returnTag;
appendReturnValuePacker(function);
}
}
unsigned Compiler::appendCalldataUnpacker(FunctionDefinition const& _function, bool _fromMemory)
{
// We do not check the calldata size, everything is zero-padded.
unsigned dataOffset = 1;
eth::Instruction load = _fromMemory ? eth::Instruction::MLOAD : eth::Instruction::CALLDATALOAD;
//@todo this can be done more efficiently, saving some CALLDATALOAD calls
for (ASTPointer<VariableDeclaration> const& var: _function.getParameters())
{
unsigned const numBytes = var->getType()->getCalldataEncodedSize();
if (numBytes == 0)
BOOST_THROW_EXCEPTION(CompilerError()
<< errinfo_sourceLocation(var->getLocation())
<< errinfo_comment("Type " + var->getType()->toString() + " not yet supported."));
if (numBytes == 32)
m_context << u256(dataOffset) << load;
else
m_context << (u256(1) << ((32 - numBytes) * 8)) << u256(dataOffset)
<< load << eth::Instruction::DIV;
dataOffset += numBytes;
}
return dataOffset;
}
void Compiler::appendReturnValuePacker(FunctionDefinition const& _function)
{
//@todo this can be also done more efficiently
unsigned dataOffset = 0;
vector<ASTPointer<VariableDeclaration>> const& parameters = _function.getReturnParameters();
for (unsigned i = 0; i < parameters.size(); ++i)
{
Type const& paramType = *parameters[i]->getType();
unsigned numBytes = paramType.getCalldataEncodedSize();
if (numBytes == 0)
BOOST_THROW_EXCEPTION(CompilerError()
<< errinfo_sourceLocation(parameters[i]->getLocation())
<< errinfo_comment("Type " + paramType.toString() + " not yet supported."));
m_context << eth::dupInstruction(parameters.size() - i);
if (numBytes != 32)
m_context << (u256(1) << ((32 - numBytes) * 8)) << eth::Instruction::MUL;
m_context << u256(dataOffset) << eth::Instruction::MSTORE;
dataOffset += numBytes;
}
// note that the stack is not cleaned up here
m_context << u256(dataOffset) << u256(0) << eth::Instruction::RETURN;
}
void Compiler::registerStateVariables(ContractDefinition const& _contract)
{
//@todo sort them?
for (ASTPointer<VariableDeclaration> const& variable: _contract.getStateVariables())
m_context.addStateVariable(*variable);
}
bool Compiler::visit(FunctionDefinition& _function)
{
//@todo to simplify this, the calling convention could by changed such that
// caller puts: [retarg0] ... [retargm] [return address] [arg0] ... [argn]
// although note that this reduces the size of the visible stack
m_context.startNewFunction();
m_returnTag = m_context.newTag();
m_breakTags.clear();
m_continueTags.clear();
m_context << m_context.getFunctionEntryLabel(_function);
// stack upon entry: [return address] [arg0] [arg1] ... [argn]
// reserve additional slots: [retarg0] ... [retargm] [localvar0] ... [localvarp]
unsigned const numArguments = _function.getParameters().size();
unsigned const numReturnValues = _function.getReturnParameters().size();
unsigned const numLocalVariables = _function.getLocalVariables().size();
for (ASTPointer<VariableDeclaration> const& variable: _function.getParameters() + _function.getReturnParameters())
m_context.addVariable(*variable);
for (VariableDeclaration const* localVariable: _function.getLocalVariables())
m_context.addVariable(*localVariable);
m_context.initializeLocalVariables(numReturnValues + numLocalVariables);
_function.getBody().accept(*this);
m_context << m_returnTag;
// Now we need to re-shuffle the stack. For this we keep a record of the stack layout
// that shows the target positions of the elements, where "-1" denotes that this element needs
// to be removed from the stack.
// Note that the fact that the return arguments are of increasing index is vital for this
// algorithm to work.
vector<int> stackLayout;
stackLayout.push_back(numReturnValues); // target of return address
stackLayout += vector<int>(numArguments, -1); // discard all arguments
for (unsigned i = 0; i < numReturnValues; ++i)
stackLayout.push_back(i);
stackLayout += vector<int>(numLocalVariables, -1);
while (stackLayout.back() != int(stackLayout.size() - 1))
if (stackLayout.back() < 0)
{
m_context << eth::Instruction::POP;
stackLayout.pop_back();
}
else
{
m_context << eth::swapInstruction(stackLayout.size() - stackLayout.back() - 1);
swap(stackLayout[stackLayout.back()], stackLayout.back());
}
//@todo assert that everything is in place now
m_context << eth::Instruction::JUMP;
return false;
}
bool Compiler::visit(IfStatement& _ifStatement)
{
ExpressionCompiler::compileExpression(m_context, _ifStatement.getCondition());
eth::AssemblyItem trueTag = m_context.appendConditionalJump();
if (_ifStatement.getFalseStatement())
_ifStatement.getFalseStatement()->accept(*this);
eth::AssemblyItem endTag = m_context.appendJumpToNew();
m_context << trueTag;
_ifStatement.getTrueStatement().accept(*this);
m_context << endTag;
return false;
}
bool Compiler::visit(WhileStatement& _whileStatement)
{
eth::AssemblyItem loopStart = m_context.newTag();
eth::AssemblyItem loopEnd = m_context.newTag();
m_continueTags.push_back(loopStart);
m_breakTags.push_back(loopEnd);
m_context << loopStart;
ExpressionCompiler::compileExpression(m_context, _whileStatement.getCondition());
m_context << eth::Instruction::ISZERO;
m_context.appendConditionalJumpTo(loopEnd);
_whileStatement.getBody().accept(*this);
m_context.appendJumpTo(loopStart);
m_context << loopEnd;
m_continueTags.pop_back();
m_breakTags.pop_back();
return false;
}
bool Compiler::visit(Continue&)
{
if (!m_continueTags.empty())
m_context.appendJumpTo(m_continueTags.back());
return false;
}
bool Compiler::visit(Break&)
{
if (!m_breakTags.empty())
m_context.appendJumpTo(m_breakTags.back());
return false;
}
bool Compiler::visit(Return& _return)
{
//@todo modifications are needed to make this work with functions returning multiple values
if (Expression* expression = _return.getExpression())
{
ExpressionCompiler::compileExpression(m_context, *expression);
VariableDeclaration const& firstVariable = *_return.getFunctionReturnParameters().getParameters().front();
ExpressionCompiler::appendTypeConversion(m_context, *expression->getType(), *firstVariable.getType());
unsigned stackPosition = m_context.baseToCurrentStackOffset(m_context.getBaseStackOffsetOfVariable(firstVariable));
m_context << eth::swapInstruction(stackPosition) << eth::Instruction::POP;
}
m_context.appendJumpTo(m_returnTag);
return false;
}
bool Compiler::visit(VariableDefinition& _variableDefinition)
{
if (Expression* expression = _variableDefinition.getExpression())
{
ExpressionCompiler::compileExpression(m_context, *expression);
ExpressionCompiler::appendTypeConversion(m_context,
*expression->getType(),
*_variableDefinition.getDeclaration().getType());
unsigned baseStackOffset = m_context.getBaseStackOffsetOfVariable(_variableDefinition.getDeclaration());
unsigned stackPosition = m_context.baseToCurrentStackOffset(baseStackOffset);
m_context << eth::swapInstruction(stackPosition) << eth::Instruction::POP;
}
return false;
}
bool Compiler::visit(ExpressionStatement& _expressionStatement)
{
Expression& expression = _expressionStatement.getExpression();
ExpressionCompiler::compileExpression(m_context, expression);
Type::Category category = expression.getType()->getCategory();
for (unsigned i = 0; i < expression.getType()->getSizeOnStack(); ++i)
m_context << eth::Instruction::POP;
return false;
}
}
}
