/*

  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/>.

*/

// SPDX-License-Identifier: GPL-3.0

/**

 * Assembly interface that ignores everything. Can be used as a backend for a compilation dry-run.

 */

#include <libyul/backends/evm/NoOutputAssembly.h>

#include <libyul/AST.h>

#include <libyul/Exceptions.h>

#include <libevmasm/Instruction.h>

#include <range/v3/view/enumerate.hpp>

#include <range/v3/view/iota.hpp>

using namespace solidity;

using namespace solidity::yul;

using namespace solidity::util;

using namespace solidity::langutil;

namespace

{

void modifyBuiltinToNoOutput(BuiltinFunctionForEVM& _builtin)

{

  _builtin.generateCode = [_builtin](FunctionCall const& _call, AbstractAssembly& _assembly, BuiltinContext&)

  {

    for (size_t i: ranges::views::iota(0u, _call.arguments.size()))

      if (!_builtin.literalArgument(i))

        _assembly.appendInstruction(evmasm::Instruction::POP);

    for (size_t i = 0; i < _builtin.numReturns; i++)

      _assembly.appendConstant(u256(0));

  };

}

}

void NoOutputAssembly::appendInstruction(evmasm::Instruction _instr)

{

  m_stackHeight += instructionInfo(_instr, m_evmVersion).ret - instructionInfo(_instr, m_evmVersion).args;

}

void NoOutputAssembly::appendConstant(u256 const&)

{

  appendInstruction(evmasm::pushInstruction(1));

}

void NoOutputAssembly::appendLabel(LabelID)

{

  appendInstruction(evmasm::Instruction::JUMPDEST);

}

void NoOutputAssembly::appendLabelReference(LabelID)

{

  appendInstruction(evmasm::pushInstruction(1));

}

NoOutputAssembly::LabelID NoOutputAssembly::newLabelId()

{

  return 1;

}

AbstractAssembly::LabelID NoOutputAssembly::namedLabel(std::string const&, size_t, size_t, std::optional<size_t>)

{

  return 1;

}

void NoOutputAssembly::appendLinkerSymbol(std::string const&)

{

  yulAssert(false, "Linker symbols not yet implemented.");

}

void NoOutputAssembly::appendVerbatim(bytes, size_t _arguments, size_t _returnVariables)

{

  m_stackHeight += static_cast<int>(_returnVariables) - static_cast<int>(_arguments);

}

void NoOutputAssembly::appendJump(int _stackDiffAfter, JumpType)

{

  appendInstruction(evmasm::Instruction::JUMP);

  m_stackHeight += _stackDiffAfter;

}

void NoOutputAssembly::appendJumpTo(LabelID _labelId, int _stackDiffAfter, JumpType _jumpType)

{

  appendLabelReference(_labelId);

  appendJump(_stackDiffAfter, _jumpType);

}

void NoOutputAssembly::appendJumpToIf(LabelID _labelId, JumpType)

{

  appendLabelReference(_labelId);

  appendInstruction(evmasm::Instruction::JUMPI);

}

void NoOutputAssembly::appendAssemblySize()

{

  appendInstruction(evmasm::Instruction::PUSH1);

}

void NoOutputAssembly::appendDupN(size_t)

{

  m_stackHeight++;

}

std::pair<std::shared_ptr<AbstractAssembly>, AbstractAssembly::SubID> NoOutputAssembly::createSubAssembly(bool, std::string)

{

  yulAssert(false, "Sub assemblies not implemented.");

  return {};

}

AbstractAssembly::FunctionID NoOutputAssembly::registerFunction(uint8_t _args, uint8_t _rets, bool)

{

  yulAssert(m_context.numFunctions <= std::numeric_limits<AbstractAssembly::FunctionID>::max());

  AbstractAssembly::FunctionID id = static_cast<AbstractAssembly::FunctionID>(m_context.numFunctions++);

  m_context.functionSignatures[id] = {_args, _rets};

  return id;

}

void NoOutputAssembly::beginFunction(FunctionID _functionID)

{

  yulAssert(m_currentFunctionID == 0, "Attempted to begin a function before ending the last one.");

  yulAssert(m_context.functionSignatures.count(_functionID) == 1, "Filling unregistered function.");

  yulAssert(m_stackHeight == 0, "Non-empty stack on beginFunction call.");

  m_currentFunctionID = _functionID;

}

void NoOutputAssembly::endFunction()

{

  yulAssert(m_currentFunctionID != 0, "End function without begin function.");

  auto const [_, rets] = m_context.functionSignatures.at(m_currentFunctionID);

  yulAssert(m_stackHeight == rets, "Stack height mismatch at function end.");

  m_currentFunctionID = 0;

}

void NoOutputAssembly::appendFunctionCall(FunctionID _functionID)

{

  auto [args, rets] = m_context.functionSignatures.at(_functionID);

  m_stackHeight += static_cast<int>(rets) - static_cast<int>(args);

  solAssert(m_stackHeight >= 0);

}

void NoOutputAssembly::appendFunctionReturn()

{

  yulAssert(m_currentFunctionID != 0, "End function without begin function.");

  auto const [_, rets] = m_context.functionSignatures.at(m_currentFunctionID);

  yulAssert(m_stackHeight == rets, "Stack height mismatch at function end.");

}

void NoOutputAssembly::appendDataOffset(std::vector<AbstractAssembly::SubID> const&)

{

  appendInstruction(evmasm::Instruction::PUSH1);

}

void NoOutputAssembly::appendDataSize(std::vector<AbstractAssembly::SubID> const&)

{

  appendInstruction(evmasm::Instruction::PUSH1);

}

AbstractAssembly::SubID NoOutputAssembly::appendData(bytes const&)

{

  return {1};

}

void NoOutputAssembly::appendImmutable(std::string const&)

{

  yulAssert(false, "loadimmutable not implemented.");

}

void NoOutputAssembly::appendImmutableAssignment(std::string const&)

{

  yulAssert(false, "setimmutable not implemented.");

}

void NoOutputAssembly::appendAuxDataLoadN(uint16_t)

{

  yulAssert(false, "auxdataloadn not implemented.");

}

void NoOutputAssembly::appendEOFCreate(ContainerID)

{

  yulAssert(false, "eofcreate not implemented.");

}

void NoOutputAssembly::appendReturnContract(ContainerID)

{

  yulAssert(false, "returncontract not implemented.");

}

NoOutputEVMDialect::NoOutputEVMDialect(EVMDialect const& _copyFrom):

  EVMDialect(_copyFrom.evmVersion(), _copyFrom.eofVersion(), _copyFrom.providesObjectAccess())

{

  // save the modified functions here - note that this only has to be done once because we modify all of

  // them in one go, later reference pointers to this static vector

  static std::vector<BuiltinFunctionForEVM> noOutputBuiltins = defineNoOutputBuiltins();

  yulAssert(m_functions.size() == noOutputBuiltins.size(), "Function count mismatch.");

  for (auto const& [index, builtinFunction]: m_functions | ranges::views::enumerate)

  {

    if (builtinFunction)

      m_functions[index] = &noOutputBuiltins[index];

    else

      m_functions[index] = nullptr;

  }

}

BuiltinFunctionForEVM const& NoOutputEVMDialect::builtin(BuiltinHandle const& _handle) const

{

  if (isVerbatimHandle(_handle))

    // for verbatims the modification is performed lazily as they are stored in a lookup table fashion

    if (

      auto& builtin = m_verbatimFunctions[_handle.id];

      !builtin

    )

    {

      builtin = std::make_unique<BuiltinFunctionForEVM>(createVerbatimFunctionFromHandle(_handle));

      modifyBuiltinToNoOutput(*builtin);

    }

  return EVMDialect::builtin(_handle);

}

std::vector<BuiltinFunctionForEVM> NoOutputEVMDialect::defineNoOutputBuiltins()

{

  std::vector<BuiltinFunctionForEVM> modifiedBuiltins;

  modifiedBuiltins.reserve(allBuiltins().functions().size());

  for (auto const& [_, builtin]: allBuiltins().functions())

  {

    auto noOutputFunction = builtin;

    modifyBuiltinToNoOutput(noOutputFunction);

    modifiedBuiltins.push_back(std::move(noOutputFunction));

  }

  return modifiedBuiltins;

}