/*
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 <libsolidity/Compiler.h>
#include <algorithm>
#include <boost/range/adaptor/reversed.hpp>
#include <libevmcore/Instruction.h>
#include <libevmasm/Assembly.h>
#include <libsolidity/AST.h>
#include <libsolidity/ExpressionCompiler.h>
#include <libsolidity/CompilerUtils.h>
using namespace std;
using namespace dev;
using namespace dev::solidity;
/**
* Simple helper class to ensure that the stack height is the same at certain places in the code.
*/
class StackHeightChecker
{
public:
StackHeightChecker(CompilerContext const& _context):
m_context(_context), stackHeight(m_context.getStackHeight()) {}
void check() { solAssert(m_context.getStackHeight() == stackHeight, "I sense a disturbance in the stack."); }
private:
CompilerContext const& m_context;
unsigned stackHeight;
};
void Compiler::compileContract(ContractDefinition const& _contract,
map<ContractDefinition const*, bytes const*> const& _contracts)
{
m_context = CompilerContext(); // clear it just in case
{
CompilerContext::LocationSetter locationSetterRunTime(m_context, _contract);
CompilerUtils(m_context).initialiseFreeMemoryPointer();
initializeContext(_contract, _contracts);
appendFunctionSelector(_contract);
set<Declaration const*> functions = m_context.getFunctionsWithoutCode();
while (!functions.empty())
{
for (Declaration const* function: functions)
{
m_context.setStackOffset(0);
function->accept(*this);
}
functions = m_context.getFunctionsWithoutCode();
}
}
// Swap the runtime context with the creation-time context
swap(m_context, m_runtimeContext);
CompilerContext::LocationSetter locationSetterCreationTime(m_context, _contract);
CompilerUtils(m_context).initialiseFreeMemoryPointer();
initializeContext(_contract, _contracts);
packIntoContractCreator(_contract, m_runtimeContext);
if (m_optimize)
m_context.optimise(m_optimizeRuns);
}
eth::AssemblyItem Compiler::getFunctionEntryLabel(FunctionDefinition const& _function) const
{
return m_runtimeContext.getFunctionEntryLabelIfExists(_function);
}
void Compiler::initializeContext(ContractDefinition const& _contract,
map<ContractDefinition const*, bytes const*> const& _contracts)
{
m_context.setCompiledContracts(_contracts);
m_context.setInheritanceHierarchy(_contract.getLinearizedBaseContracts());
registerStateVariables(_contract);
m_context.resetVisitedNodes(&_contract);
}
void Compiler::packIntoContractCreator(ContractDefinition const& _contract, CompilerContext const& _runtimeContext)
{
// Determine the arguments that are used for the base constructors.
std::vector<ContractDefinition const*> const& bases = _contract.getLinearizedBaseContracts();
for (ContractDefinition const* contract: bases)
{
if (FunctionDefinition const* constructor = contract->getConstructor())
for (auto const& modifier: constructor->getModifiers())
{
auto baseContract = dynamic_cast<ContractDefinition const*>(
&modifier->getName()->getReferencedDeclaration());
if (baseContract)
if (m_baseArguments.count(baseContract->getConstructor()) == 0)
m_baseArguments[baseContract->getConstructor()] = &modifier->getArguments();
}
for (ASTPointer<InheritanceSpecifier> const& base: contract->getBaseContracts())
{
ContractDefinition const* baseContract = dynamic_cast<ContractDefinition const*>(
&base->getName()->getReferencedDeclaration());
solAssert(baseContract, "");
if (m_baseArguments.count(baseContract->getConstructor()) == 0)
m_baseArguments[baseContract->getConstructor()] = &base->getArguments();
}
}
// Initialization of state variables in base-to-derived order.
for (ContractDefinition const* contract: boost::adaptors::reverse(bases))
initializeStateVariables(*contract);
if (FunctionDefinition const* constructor = _contract.getConstructor())
appendConstructor(*constructor);
else if (auto c = m_context.getNextConstructor(_contract))
appendBaseConstructor(*c);
eth::AssemblyItem runtimeSub = m_context.addSubroutine(_runtimeContext.getAssembly());
solAssert(runtimeSub.data() < numeric_limits<size_t>::max(), "");
m_runtimeSub = size_t(runtimeSub.data());
// stack contains sub size
m_context << eth::Instruction::DUP1 << runtimeSub << u256(0) << eth::Instruction::CODECOPY;
m_context << u256(0) << eth::Instruction::RETURN;
// note that we have to include the functions again because of absolute jump labels
set<Declaration const*> functions = m_context.getFunctionsWithoutCode();
while (!functions.empty())
{
for (Declaration const* function: functions)
function->accept(*this);
functions = m_context.getFunctionsWithoutCode();
}
}
void Compiler::appendBaseConstructor(FunctionDefinition const& _constructor)
{
CompilerContext::LocationSetter locationSetter(m_context, _constructor);
FunctionType constructorType(_constructor);
if (!constructorType.getParameterTypes().empty())
{
solAssert(m_baseArguments.count(&_constructor), "");
std::vector<ASTPointer<Expression>> const* arguments = m_baseArguments[&_constructor];
solAssert(arguments, "");
for (unsigned i = 0; i < arguments->size(); ++i)
compileExpression(*(arguments->at(i)), constructorType.getParameterTypes()[i]);
}
_constructor.accept(*this);
}
void Compiler::appendConstructor(FunctionDefinition const& _constructor)
{
CompilerContext::LocationSetter locationSetter(m_context, _constructor);
// copy constructor arguments from code to memory and then to stack, they are supplied after the actual program
if (!_constructor.getParameters().empty())
{
unsigned argumentSize = 0;
for (ASTPointer<VariableDeclaration> const& var: _constructor.getParameters())
if (var->getType()->isDynamicallySized())
{
argumentSize = 0;
break;
}
else
argumentSize += var->getType()->getCalldataEncodedSize();
CompilerUtils(m_context).fetchFreeMemoryPointer();
if (argumentSize == 0)
{
// argument size is dynamic, use CODESIZE to determine it
m_context.appendProgramSize(); // program itself
// CODESIZE is program plus manually added arguments
m_context << eth::Instruction::CODESIZE << eth::Instruction::SUB;
}
else
m_context << u256(argumentSize);
// stack: <memptr> <argument size>
m_context << eth::Instruction::DUP1;
m_context.appendProgramSize();
m_context << eth::Instruction::DUP4 << eth::Instruction::CODECOPY;
m_context << eth::Instruction::ADD;
CompilerUtils(m_context).storeFreeMemoryPointer();
appendCalldataUnpacker(
FunctionType(_constructor).getParameterTypes(),
true,
CompilerUtils::freeMemoryPointer + 0x20
);
}
_constructor.accept(*this);
}
void Compiler::appendFunctionSelector(ContractDefinition const& _contract)
{
map<FixedHash<4>, FunctionTypePointer> interfaceFunctions = _contract.getInterfaceFunctions();
map<FixedHash<4>, const eth::AssemblyItem> callDataUnpackerEntryPoints;
FunctionDefinition const* fallback = _contract.getFallbackFunction();
eth::AssemblyItem notFound = m_context.newTag();
// shortcut messages without data if we have many functions in order to be able to receive
// ether with constant gas
if (interfaceFunctions.size() > 5 || fallback)
{
m_context << eth::Instruction::CALLDATASIZE << eth::Instruction::ISZERO;
m_context.appendConditionalJumpTo(notFound);
}
// retrieve the function signature hash from the calldata
if (!interfaceFunctions.empty())
CompilerUtils(m_context).loadFromMemory(0, IntegerType(CompilerUtils::dataStartOffset * 8), true);
// stack now is: 1 0 <funhash>
for (auto const& it: interfaceFunctions)
{
callDataUnpackerEntryPoints.insert(std::make_pair(it.first, m_context.newTag()));
m_context << eth::dupInstruction(1) << u256(FixedHash<4>::Arith(it.first)) << eth::Instruction::EQ;
m_context.appendConditionalJumpTo(callDataUnpackerEntryPoints.at(it.first));
}
m_context.appendJumpTo(notFound);
m_context << notFound;
if (fallback)
{
eth::AssemblyItem returnTag = m_context.pushNewTag();
fallback->accept(*this);
m_context << returnTag;
appendReturnValuePacker(FunctionType(*fallback).getReturnParameterTypes());
}
else
m_context << eth::Instruction::STOP; // function not found
for (auto const& it: interfaceFunctions)
{
FunctionTypePointer const& functionType = it.second;
solAssert(functionType->hasDeclaration(), "");
CompilerContext::LocationSetter locationSetter(m_context, functionType->getDeclaration());
m_context << callDataUnpackerEntryPoints.at(it.first);
eth::AssemblyItem returnTag = m_context.pushNewTag();
appendCalldataUnpacker(functionType->getParameterTypes());
m_context.appendJumpTo(m_context.getFunctionEntryLabel(functionType->getDeclaration()));
m_context << returnTag;
appendReturnValuePacker(functionType->getReturnParameterTypes());
}
}
void Compiler::appendCalldataUnpacker(
TypePointers const& _typeParameters,
bool _fromMemory,
u256 _startOffset
)
{
// We do not check the calldata size, everything is zero-paddedd
//@todo this does not yet support nested dynamic arrays
if (_startOffset == u256(-1))
_startOffset = u256(CompilerUtils::dataStartOffset);
m_context << _startOffset;
for (TypePointer const& type: _typeParameters)
{
// stack: v1 v2 ... v(k-1) mem_offset
switch (type->getCategory())
{
case Type::Category::Array:
{
auto const& arrayType = dynamic_cast<ArrayType const&>(*type);
solAssert(arrayType.location() != DataLocation::Storage, "");
solAssert(!arrayType.getBaseType()->isDynamicallySized(), "Nested arrays not yet implemented.");
if (_fromMemory)
{
solAssert(
arrayType.getBaseType()->isValueType(),
"Nested memory arrays not yet implemented here."
);
// @todo If base type is an array or struct, it is still calldata-style encoded, so
// we would have to convert it like below.
solAssert(arrayType.location() == DataLocation::Memory, "");
// compute data pointer
m_context << eth::Instruction::DUP1 << eth::Instruction::MLOAD;
//@todo once we support nested arrays, this offset needs to be dynamic.
m_context << _startOffset << eth::Instruction::ADD;
m_context << eth::Instruction::SWAP1 << u256(0x20) << eth::Instruction::ADD;
}
else
{
// first load from calldata and potentially convert to memory if arrayType is memory
TypePointer calldataType = arrayType.copyForLocation(DataLocation::CallData, false);
if (calldataType->isDynamicallySized())
{
// put on stack: data_pointer length
CompilerUtils(m_context).loadFromMemoryDynamic(IntegerType(256), !_fromMemory);
// stack: data_offset next_pointer
//@todo once we support nested arrays, this offset needs to be dynamic.
m_context << eth::Instruction::SWAP1 << _startOffset << eth::Instruction::ADD;
// stack: next_pointer data_pointer
// retrieve length
CompilerUtils(m_context).loadFromMemoryDynamic(IntegerType(256), !_fromMemory, true);
// stack: next_pointer length data_pointer
m_context << eth::Instruction::SWAP2;
}
else
{
// leave the pointer on the stack
m_context << eth::Instruction::DUP1;
m_context << u256(calldataType->getCalldataEncodedSize()) << eth::Instruction::ADD;
}
if (arrayType.location() == DataLocation::Memory)
{
// stack: calldata_ref [length] next_calldata
// copy to memory
// move calldata type up again
CompilerUtils(m_context).moveIntoStack(calldataType->getSizeOnStack());
CompilerUtils(m_context).convertType(*calldataType, arrayType);
// fetch next pointer again
CompilerUtils(m_context).moveToStackTop(arrayType.getSizeOnStack());
}
}
break;
}
default:
solAssert(!type->isDynamicallySized(), "Unknown dynamically sized type: " + type->toString());
CompilerUtils(m_context).loadFromMemoryDynamic(*type, !_fromMemory, true);
}
}
m_context << eth::Instruction::POP;
}
void Compiler::appendReturnValuePacker(TypePointers const& _typeParameters)
{
CompilerUtils utils(m_context);
if (_typeParameters.empty())
m_context << eth::Instruction::STOP;
else
{
utils.fetchFreeMemoryPointer();
//@todo optimization: if we return a single memory array, there should be enough space before
// its data to add the needed parts and we avoid a memory copy.
utils.encodeToMemory(_typeParameters, _typeParameters);
utils.toSizeAfterFreeMemoryPointer();
m_context << eth::Instruction::RETURN;
}
}
void Compiler::registerStateVariables(ContractDefinition const& _contract)
{
for (auto const& var: ContractType(_contract).getStateVariables())
m_context.addStateVariable(*get<0>(var), get<1>(var), get<2>(var));
}
void Compiler::initializeStateVariables(ContractDefinition const& _contract)
{
for (ASTPointer<VariableDeclaration> const& variable: _contract.getStateVariables())
if (variable->getValue() && !variable->isConstant())
ExpressionCompiler(m_context, m_optimize).appendStateVariableInitialization(*variable);
}
bool Compiler::visit(VariableDeclaration const& _variableDeclaration)
{
solAssert(_variableDeclaration.isStateVariable(), "Compiler visit to non-state variable declaration.");
CompilerContext::LocationSetter locationSetter(m_context, _variableDeclaration);
m_context.startFunction(_variableDeclaration);
m_breakTags.clear();
m_continueTags.clear();
ExpressionCompiler(m_context, m_optimize).appendStateVariableAccessor(_variableDeclaration);
return false;
}
bool Compiler::visit(FunctionDefinition const& _function)
{
CompilerContext::LocationSetter locationSetter(m_context, _function);
m_context.startFunction(_function);
// stack upon entry: [return address] [arg0] [arg1] ... [argn]
// reserve additional slots: [retarg0] ... [retargm] [localvar0] ... [localvarp]
unsigned parametersSize = CompilerUtils::getSizeOnStack(_function.getParameters());
if (!_function.isConstructor())
// adding 1 for return address.
m_context.adjustStackOffset(parametersSize + 1);
for (ASTPointer<VariableDeclaration const> const& variable: _function.getParameters())
{
m_context.addVariable(*variable, parametersSize);
parametersSize -= variable->getType()->getSizeOnStack();
}
for (ASTPointer<VariableDeclaration const> const& variable: _function.getReturnParameters())
appendStackVariableInitialisation(*variable);
for (VariableDeclaration const* localVariable: _function.getLocalVariables())
appendStackVariableInitialisation(*localVariable);
if (_function.isConstructor())
if (auto c = m_context.getNextConstructor(dynamic_cast<ContractDefinition const&>(*_function.getScope())))
appendBaseConstructor(*c);
m_returnTag = m_context.newTag();
m_breakTags.clear();
m_continueTags.clear();
m_stackCleanupForReturn = 0;
m_currentFunction = &_function;
m_modifierDepth = 0;
appendModifierOrFunctionCode();
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.
unsigned const c_argumentsSize = CompilerUtils::getSizeOnStack(_function.getParameters());
unsigned const c_returnValuesSize = CompilerUtils::getSizeOnStack(_function.getReturnParameters());
unsigned const c_localVariablesSize = CompilerUtils::getSizeOnStack(_function.getLocalVariables());
vector<int> stackLayout;
stackLayout.push_back(c_returnValuesSize); // target of return address
stackLayout += vector<int>(c_argumentsSize, -1); // discard all arguments
for (unsigned i = 0; i < c_returnValuesSize; ++i)
stackLayout.push_back(i);
stackLayout += vector<int>(c_localVariablesSize, -1);
solAssert(stackLayout.size() <= 17, "Stack too deep, try removing local variables.");
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
for (ASTPointer<VariableDeclaration const> const& variable: _function.getParameters() + _function.getReturnParameters())
m_context.removeVariable(*variable);
for (VariableDeclaration const* localVariable: _function.getLocalVariables())
m_context.removeVariable(*localVariable);
m_context.adjustStackOffset(-(int)c_returnValuesSize);
if (!_function.isConstructor())
m_context.appendJump(eth::AssemblyItem::JumpType::OutOfFunction);
return false;
}
bool Compiler::visit(IfStatement const& _ifStatement)
{
StackHeightChecker checker(m_context);
CompilerContext::LocationSetter locationSetter(m_context, _ifStatement);
compileExpression(_ifStatement.getCondition());
m_context << eth::Instruction::ISZERO;
eth::AssemblyItem falseTag = m_context.appendConditionalJump();
eth::AssemblyItem endTag = falseTag;
_ifStatement.getTrueStatement().accept(*this);
if (_ifStatement.getFalseStatement())
{
endTag = m_context.appendJumpToNew();
m_context << falseTag;
_ifStatement.getFalseStatement()->accept(*this);
}
m_context << endTag;
checker.check();
return false;
}
bool Compiler::visit(WhileStatement const& _whileStatement)
{
StackHeightChecker checker(m_context);
CompilerContext::LocationSetter locationSetter(m_context, _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;
compileExpression(_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();
checker.check();
return false;
}
bool Compiler::visit(ForStatement const& _forStatement)
{
StackHeightChecker checker(m_context);
CompilerContext::LocationSetter locationSetter(m_context, _forStatement);
eth::AssemblyItem loopStart = m_context.newTag();
eth::AssemblyItem loopEnd = m_context.newTag();
eth::AssemblyItem loopNext = m_context.newTag();
m_continueTags.push_back(loopNext);
m_breakTags.push_back(loopEnd);
if (_forStatement.getInitializationExpression())
_forStatement.getInitializationExpression()->accept(*this);
m_context << loopStart;
// if there is no terminating condition in for, default is to always be true
if (_forStatement.getCondition())
{
compileExpression(*_forStatement.getCondition());
m_context << eth::Instruction::ISZERO;
m_context.appendConditionalJumpTo(loopEnd);
}
_forStatement.getBody().accept(*this);
m_context << loopNext;
// for's loop expression if existing
if (_forStatement.getLoopExpression())
_forStatement.getLoopExpression()->accept(*this);
m_context.appendJumpTo(loopStart);
m_context << loopEnd;
m_continueTags.pop_back();
m_breakTags.pop_back();
checker.check();
return false;
}
bool Compiler::visit(Continue const& _continueStatement)
{
CompilerContext::LocationSetter locationSetter(m_context, _continueStatement);
if (!m_continueTags.empty())
m_context.appendJumpTo(m_continueTags.back());
return false;
}
bool Compiler::visit(Break const& _breakStatement)
{
CompilerContext::LocationSetter locationSetter(m_context, _breakStatement);
if (!m_breakTags.empty())
m_context.appendJumpTo(m_breakTags.back());
return false;
}
bool Compiler::visit(Return const& _return)
{
CompilerContext::LocationSetter locationSetter(m_context, _return);
//@todo modifications are needed to make this work with functions returning multiple values
if (Expression const* expression = _return.getExpression())
{
solAssert(_return.getFunctionReturnParameters(), "Invalid return parameters pointer.");
VariableDeclaration const& firstVariable = *_return.getFunctionReturnParameters()->getParameters().front();
compileExpression(*expression, firstVariable.getType());
CompilerUtils(m_context).moveToStackVariable(firstVariable);
}
for (unsigned i = 0; i < m_stackCleanupForReturn; ++i)
m_context << eth::Instruction::POP;
m_context.appendJumpTo(m_returnTag);
m_context.adjustStackOffset(m_stackCleanupForReturn);
return false;
}
bool Compiler::visit(VariableDeclarationStatement const& _variableDeclarationStatement)
{
StackHeightChecker checker(m_context);
CompilerContext::LocationSetter locationSetter(m_context, _variableDeclarationStatement);
if (Expression const* expression = _variableDeclarationStatement.getExpression())
{
compileExpression(*expression, _variableDeclarationStatement.getDeclaration().getType());
CompilerUtils(m_context).moveToStackVariable(_variableDeclarationStatement.getDeclaration());
}
checker.check();
return false;
}
bool Compiler::visit(ExpressionStatement const& _expressionStatement)
{
StackHeightChecker checker(m_context);
CompilerContext::LocationSetter locationSetter(m_context, _expressionStatement);
Expression const& expression = _expressionStatement.getExpression();
compileExpression(expression);
CompilerUtils(m_context).popStackElement(*expression.getType());
checker.check();
return false;
}
bool Compiler::visit(PlaceholderStatement const& _placeholderStatement)
{
StackHeightChecker checker(m_context);
CompilerContext::LocationSetter locationSetter(m_context, _placeholderStatement);
++m_modifierDepth;
appendModifierOrFunctionCode();
--m_modifierDepth;
checker.check();
return true;
}
void Compiler::appendModifierOrFunctionCode()
{
solAssert(m_currentFunction, "");
if (m_modifierDepth >= m_currentFunction->getModifiers().size())
m_currentFunction->getBody().accept(*this);
else
{
ASTPointer<ModifierInvocation> const& modifierInvocation = m_currentFunction->getModifiers()[m_modifierDepth];
// constructor call should be excluded
if (dynamic_cast<ContractDefinition const*>(&modifierInvocation->getName()->getReferencedDeclaration()))
{
++m_modifierDepth;
appendModifierOrFunctionCode();
--m_modifierDepth;
return;
}
ModifierDefinition const& modifier = m_context.getFunctionModifier(modifierInvocation->getName()->getName());
CompilerContext::LocationSetter locationSetter(m_context, modifier);
solAssert(modifier.getParameters().size() == modifierInvocation->getArguments().size(), "");
for (unsigned i = 0; i < modifier.getParameters().size(); ++i)
{
m_context.addVariable(*modifier.getParameters()[i]);
compileExpression(*modifierInvocation->getArguments()[i],
modifier.getParameters()[i]->getType());
}
for (VariableDeclaration const* localVariable: modifier.getLocalVariables())
appendStackVariableInitialisation(*localVariable);
unsigned const c_stackSurplus = CompilerUtils::getSizeOnStack(modifier.getParameters()) +
CompilerUtils::getSizeOnStack(modifier.getLocalVariables());
m_stackCleanupForReturn += c_stackSurplus;
modifier.getBody().accept(*this);
for (unsigned i = 0; i < c_stackSurplus; ++i)
m_context << eth::Instruction::POP;
m_stackCleanupForReturn -= c_stackSurplus;
}
}
void Compiler::appendStackVariableInitialisation(VariableDeclaration const& _variable)
{
CompilerContext::LocationSetter location(m_context, _variable);
m_context.addVariable(_variable);
CompilerUtils(m_context).pushZeroValue(*_variable.getType());
}
void Compiler::compileExpression(Expression const& _expression, TypePointer const& _targetType)
{
ExpressionCompiler expressionCompiler(m_context, m_optimize);
expressionCompiler.compile(_expression);
if (_targetType)
CompilerUtils(m_context).convertType(*_expression.getType(), *_targetType);
}
