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);
}
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;
}
