/*
This file is part of solidity.
solidity 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.
solidity 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 solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2016
* Code-generating part of inline assembly.
*/
#include <libsolidity/inlineasm/AsmCodeGen.h>
#include <memory>
#include <functional>
#include <libdevcore/CommonIO.h>
#include <libevmasm/Assembly.h>
#include <libevmasm/SourceLocation.h>
#include <libevmasm/Instruction.h>
#include <libsolidity/inlineasm/AsmParser.h>
#include <libsolidity/inlineasm/AsmData.h>
using namespace std;
using namespace dev;
using namespace dev::solidity;
using namespace dev::solidity::assembly;
struct GeneratorState
{
GeneratorState(ErrorList& _errors, eth::Assembly& _assembly):
errors(_errors), assembly(_assembly) {}
void addError(Error::Type _type, std::string const& _description, SourceLocation const& _location = SourceLocation())
{
auto err = make_shared<Error>(_type);
if (!_location.isEmpty())
*err << errinfo_sourceLocation(_location);
*err << errinfo_comment(_description);
errors.push_back(err);
}
int const* findVariable(string const& _variableName) const
{
auto localVariable = find_if(
variables.rbegin(),
variables.rend(),
[&](pair<string, int> const& _var) { return _var.first == _variableName; }
);
return localVariable != variables.rend() ? &localVariable->second : nullptr;
}
eth::AssemblyItem const* findLabel(string const& _labelName) const
{
auto label = find_if(
labels.begin(),
labels.end(),
[&](pair<string, eth::AssemblyItem> const& _label) { return _label.first == _labelName; }
);
return label != labels.end() ? &label->second : nullptr;
}
map<string, eth::AssemblyItem> labels;
vector<pair<string, int>> variables; ///< name plus stack height
ErrorList& errors;
eth::Assembly& assembly;
};
/**
* Scans the inline assembly data for labels, creates tags in the assembly and searches for
* duplicate labels.
*/
class LabelOrganizer: public boost::static_visitor<>
{
public:
LabelOrganizer(GeneratorState& _state): m_state(_state)
{
// Make the Solidity ErrorTag available to inline assembly
m_state.labels.insert(make_pair("invalidJumpLabel", m_state.assembly.errorTag()));
}
template <class T>
void operator()(T const& /*_item*/) { }
void operator()(Label const& _item)
{
if (m_state.labels.count(_item.name))
//@TODO secondary location
m_state.addError(
Error::Type::DeclarationError,
"Label " + _item.name + " declared twice.",
_item.location
);
m_state.labels.insert(make_pair(_item.name, m_state.assembly.newTag()));
}
void operator()(assembly::Block const& _block)
{
std::for_each(_block.statements.begin(), _block.statements.end(), boost::apply_visitor(*this));
}
private:
GeneratorState& m_state;
};
class CodeTransform: public boost::static_visitor<>
{
public:
/// Create the code transformer which appends assembly to _state.assembly when called
/// with parsed assembly data.
/// @param _identifierAccess used to resolve identifiers external to the inline assembly
explicit CodeTransform(
GeneratorState& _state,
assembly::CodeGenerator::IdentifierAccess const& _identifierAccess = assembly::CodeGenerator::IdentifierAccess()
):
m_state(_state)
{
if (_identifierAccess)
m_identifierAccess = _identifierAccess;
else
m_identifierAccess = [](assembly::Identifier const&, eth::Assembly&, CodeGenerator::IdentifierContext) { return false; };
}
void operator()(assembly::Instruction const& _instruction)
{
m_state.assembly.setSourceLocation(_instruction.location);
m_state.assembly.append(_instruction.instruction);
}
void operator()(assembly::Literal const& _literal)
{
m_state.assembly.setSourceLocation(_literal.location);
if (_literal.isNumber)
m_state.assembly.append(u256(_literal.value));
else if (_literal.value.size() > 32)
{
m_state.addError(
Error::Type::TypeError,
"String literal too long (" + boost::lexical_cast<string>(_literal.value.size()) + " > 32)"
);
m_state.assembly.append(u256(0));
}
else
m_state.assembly.append(_literal.value);
}
void operator()(assembly::Identifier const& _identifier)
{
m_state.assembly.setSourceLocation(_identifier.location);
// First search local variables, then labels, then externals.
if (int const* stackHeight = m_state.findVariable(_identifier.name))
{
int heightDiff = m_state.assembly.deposit() - *stackHeight;
if (heightDiff <= 0 || heightDiff > 16)
{
m_state.addError(
Error::Type::TypeError,
"Variable inaccessible, too deep inside stack (" + boost::lexical_cast<string>(heightDiff) + ")",
_identifier.location
);
m_state.assembly.append(u256(0));
}
else
m_state.assembly.append(solidity::dupInstruction(heightDiff));
return;
}
else if (eth::AssemblyItem const* label = m_state.findLabel(_identifier.name))
m_state.assembly.append(label->pushTag());
else if (!m_identifierAccess(_identifier, m_state.assembly, CodeGenerator::IdentifierContext::RValue))
{
m_state.addError(
Error::Type::DeclarationError,
"Identifier not found or not unique",
_identifier.location
);
m_state.assembly.append(u256(0));
}
}
void operator()(FunctionalInstruction const& _instr)
{
for (auto it = _instr.arguments.rbegin(); it != _instr.arguments.rend(); ++it)
{
int height = m_state.assembly.deposit();
boost::apply_visitor(*this, *it);
expectDeposit(1, height, locationOf(*it));
}
(*this)(_instr.instruction);
}
void operator()(Label const& _label)
{
m_state.assembly.setSourceLocation(_label.location);
m_state.assembly.append(m_state.labels.at(_label.name));
}
void operator()(assembly::Assignment const& _assignment)
{
m_state.assembly.setSourceLocation(_assignment.location);
generateAssignment(_assignment.variableName, _assignment.location);
}
void operator()(FunctionalAssignment const& _assignment)
{
int height = m_state.assembly.deposit();
boost::apply_visitor(*this, *_assignment.value);
expectDeposit(1, height, locationOf(*_assignment.value));
m_state.assembly.setSourceLocation(_assignment.location);
generateAssignment(_assignment.variableName, _assignment.location);
}
void operator()(assembly::VariableDeclaration const& _varDecl)
{
int height = m_state.assembly.deposit();
boost::apply_visitor(*this, *_varDecl.value);
expectDeposit(1, height, locationOf(*_varDecl.value));
m_state.variables.push_back(make_pair(_varDecl.name, height));
}
void operator()(assembly::Block const& _block)
{
size_t numVariables = m_state.variables.size();
int deposit = m_state.assembly.deposit();
std::for_each(_block.statements.begin(), _block.statements.end(), boost::apply_visitor(*this));
// pop variables
while (m_state.variables.size() > numVariables)
{
m_state.assembly.append(solidity::Instruction::POP);
m_state.variables.pop_back();
}
m_state.assembly.setSourceLocation(_block.location);
deposit = m_state.assembly.deposit() - deposit;
// issue warnings for stack height discrepancies
if (deposit < 0)
{
m_state.addError(
Error::Type::Warning,
"Inline assembly block is not balanced. It takes " + toString(-deposit) + " item(s) from the stack.",
_block.location
);
}
else if (deposit > 0)
{
m_state.addError(
Error::Type::Warning,
"Inline assembly block is not balanced. It leaves " + toString(deposit) + " item(s) on the stack.",
_block.location
);
}
}
private:
void generateAssignment(assembly::Identifier const& _variableName, SourceLocation const& _location)
{
if (int const* stackHeight = m_state.findVariable(_variableName.name))
{
int heightDiff = m_state.assembly.deposit() - *stackHeight - 1;
if (heightDiff <= 0 || heightDiff > 16)
m_state.addError(
Error::Type::TypeError,
"Variable inaccessible, too deep inside stack (" + boost::lexical_cast<string>(heightDiff) + ")",
_location
);
else
m_state.assembly.append(solidity::swapInstruction(heightDiff));
m_state.assembly.append(solidity::Instruction::POP);
return;
}
else if (!m_identifierAccess(_variableName, m_state.assembly, CodeGenerator::IdentifierContext::LValue))
m_state.addError(
Error::Type::DeclarationError,
"Identifier \"" + string(_variableName.name) + "\" not found, not unique or not lvalue."
);
}
void expectDeposit(int _deposit, int _oldHeight, SourceLocation const& _location)
{
if (m_state.assembly.deposit() != _oldHeight + 1)
m_state.addError(Error::Type::TypeError,
"Expected instruction(s) to deposit " +
boost::lexical_cast<string>(_deposit) +
" item(s) to the stack, but did deposit " +
boost::lexical_cast<string>(m_state.assembly.deposit() - _oldHeight) +
" item(s).",
_location
);
}
GeneratorState& m_state;
assembly::CodeGenerator::IdentifierAccess m_identifierAccess;
};
bool assembly::CodeGenerator::typeCheck(assembly::CodeGenerator::IdentifierAccess const& _identifierAccess)
{
size_t initialErrorLen = m_errors.size();
eth::Assembly assembly;
GeneratorState state(m_errors, assembly);
(LabelOrganizer(state))(m_parsedData);
(CodeTransform(state, _identifierAccess))(m_parsedData);
return m_errors.size() == initialErrorLen;
}
eth::Assembly assembly::CodeGenerator::assemble(assembly::CodeGenerator::IdentifierAccess const& _identifierAccess)
{
eth::Assembly assembly;
GeneratorState state(m_errors, assembly);
(LabelOrganizer(state))(m_parsedData);
(CodeTransform(state, _identifierAccess))(m_parsedData);
return assembly;
}
void assembly::CodeGenerator::assemble(eth::Assembly& _assembly, assembly::CodeGenerator::IdentifierAccess const& _identifierAccess)
{
GeneratorState state(m_errors, _assembly);
(LabelOrganizer(state))(m_parsedData);
(CodeTransform(state, _identifierAccess))(m_parsedData);
}
