/*

  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

#include <libevmasm/AssemblyItem.h>

#include <libevmasm/Assembly.h>

#include <libsolutil/CommonData.h>

#include <libsolutil/CommonIO.h>

#include <libsolutil/Numeric.h>

#include <libsolutil/StringUtils.h>

#include <libsolutil/FixedHash.h>

#include <liblangutil/SourceLocation.h>

#include <fstream>

#include <limits>

using namespace std;

using namespace solidity;

using namespace solidity::evmasm;

using namespace solidity::langutil;

static_assert(sizeof(size_t) <= 8, "size_t must be at most 64-bits wide");

namespace

{

string toStringInHex(u256 _value)

{

  std::stringstream hexStr;

  hexStr << std::uppercase << hex << _value;

  return hexStr.str();

}

}

AssemblyItem AssemblyItem::toSubAssemblyTag(size_t _subId) const

{

  assertThrow(data() < (u256(1) << 64), util::Exception, "Tag already has subassembly set.");

  assertThrow(m_type == PushTag || m_type == Tag, util::Exception, "");

  auto tag = static_cast<size_t>(u256(data()) & 0xffffffffffffffffULL);

  AssemblyItem r = *this;

  r.m_type = PushTag;

  r.setPushTagSubIdAndTag(_subId, tag);

  return r;

}

pair<size_t, size_t> AssemblyItem::splitForeignPushTag() const

{

  assertThrow(m_type == PushTag || m_type == Tag, util::Exception, "");

  u256 combined = u256(data());

  size_t subId = static_cast<size_t>((combined >> 64) - 1);

  size_t tag = static_cast<size_t>(combined & 0xffffffffffffffffULL);

  return make_pair(subId, tag);

}

pair<string, string> AssemblyItem::nameAndData() const

{

  switch (type())

  {

  case Operation:

    return {instructionInfo(instruction()).name, m_data != nullptr ? toStringInHex(*m_data) : ""};

  case Push:

    return {"PUSH", toStringInHex(data())};

  case PushTag:

    if (data() == 0)

      return {"PUSH [ErrorTag]", ""};

    else

      return {"PUSH [tag]", util::toString(data())};

  case PushSub:

    return {"PUSH [$]", toString(util::h256(data()))};

  case PushSubSize:

    return {"PUSH #[$]", toString(util::h256(data()))};

  case PushProgramSize:

    return {"PUSHSIZE", ""};

  case PushLibraryAddress:

    return {"PUSHLIB", toString(util::h256(data()))};

  case PushDeployTimeAddress:

    return {"PUSHDEPLOYADDRESS", ""};

  case PushImmutable:

    return {"PUSHIMMUTABLE", toString(util::h256(data()))};

  case AssignImmutable:

    return {"ASSIGNIMMUTABLE", toString(util::h256(data()))};

  case Tag:

    return {"tag", util::toString(data())};

  case PushData:

    return {"PUSH data", toStringInHex(data())};

  case VerbatimBytecode:

    return {"VERBATIM", util::toHex(verbatimData())};

  default:

    assertThrow(false, InvalidOpcode, "");

  }

}

void AssemblyItem::setPushTagSubIdAndTag(size_t _subId, size_t _tag)

{

  assertThrow(m_type == PushTag || m_type == Tag, util::Exception, "");

  u256 data = _tag;

  if (_subId != numeric_limits<size_t>::max())

    data |= (u256(_subId) + 1) << 64;

  setData(data);

}

size_t AssemblyItem::bytesRequired(size_t _addressLength, Precision _precision) const

{

  switch (m_type)

  {

  case Operation:

  case Tag: // 1 byte for the JUMPDEST

    return 1;

  case Push:

    return 1 + max<size_t>(1, numberEncodingSize(data()));

  case PushSubSize:

  case PushProgramSize:

    return 1 + 4;    // worst case: a 16MB program

  case PushTag:

  case PushData:

  case PushSub:

    return 1 + _addressLength;

  case PushLibraryAddress:

  case PushDeployTimeAddress:

    return 1 + 20;

  case PushImmutable:

    return 1 + 32;

  case AssignImmutable:

  {

    unsigned long immutableOccurrences = 0;

    // Skip exact immutables count if no precise count was requested

    if (_precision == Precision::Approximate)

      immutableOccurrences = 1; // Assume one immut. ref.

    else

    {

      solAssert(m_immutableOccurrences, "No immutable references. `bytesRequired()` called before assembly()?");

      immutableOccurrences = m_immutableOccurrences.value();

    }

    if (immutableOccurrences != 0)

      // (DUP DUP PUSH <n> ADD MSTORE)* (PUSH <n> ADD MSTORE)

      return (immutableOccurrences - 1) * (5 + 32) + (3 + 32);

    else

      // POP POP

      return 2;

  }

  case VerbatimBytecode:

    return std::get<2>(*m_verbatimBytecode).size();

  default:

    break;

  }

  assertThrow(false, InvalidOpcode, "");

}

size_t AssemblyItem::arguments() const

{

  if (type() == Operation)

    return static_cast<size_t>(instructionInfo(instruction()).args);

  else if (type() == VerbatimBytecode)

    return get<0>(*m_verbatimBytecode);

  else if (type() == AssignImmutable)

    return 2;

  else

    return 0;

}

size_t AssemblyItem::returnValues() const

{

  switch (m_type)

  {

  case Operation:

    return static_cast<size_t>(instructionInfo(instruction()).ret);

  case Push:

  case PushTag:

  case PushData:

  case PushSub:

  case PushSubSize:

  case PushProgramSize:

  case PushLibraryAddress:

  case PushImmutable:

  case PushDeployTimeAddress:

    return 1;

  case Tag:

    return 0;

  case VerbatimBytecode:

    return get<1>(*m_verbatimBytecode);

  default:

    break;

  }

  return 0;

}

bool AssemblyItem::canBeFunctional() const

{

  if (m_jumpType != JumpType::Ordinary)

    return false;

  switch (m_type)

  {

  case Operation:

    return !isDupInstruction(instruction()) && !isSwapInstruction(instruction());

  case Push:

  case PushTag:

  case PushData:

  case PushSub:

  case PushSubSize:

  case PushProgramSize:

  case PushLibraryAddress:

  case PushDeployTimeAddress:

  case PushImmutable:

    return true;

  case Tag:

    return false;

  default:

    break;

  }

  return false;

}

string AssemblyItem::getJumpTypeAsString() const

{

  switch (m_jumpType)

  {

  case JumpType::IntoFunction:

    return "[in]";

  case JumpType::OutOfFunction:

    return "[out]";

  case JumpType::Ordinary:

  default:

    return "";

  }

}

string AssemblyItem::toAssemblyText(Assembly const& _assembly) const

{

  string text;

  switch (type())

  {

  case Operation:

  {

    assertThrow(isValidInstruction(instruction()), AssemblyException, "Invalid instruction.");

    text = util::toLower(instructionInfo(instruction()).name);

    break;

  }

  case Push:

    text = toHex(toCompactBigEndian(data(), 1), util::HexPrefix::Add);

    break;

  case PushTag:

  {

    size_t sub{0};

    size_t tag{0};

    tie(sub, tag) = splitForeignPushTag();

    if (sub == numeric_limits<size_t>::max())

      text = string("tag_") + to_string(tag);

    else

      text = string("tag_") + to_string(sub) + "_" + to_string(tag);

    break;

  }

  case Tag:

    assertThrow(data() < 0x10000, AssemblyException, "Declaration of sub-assembly tag.");

    text = string("tag_") + to_string(static_cast<size_t>(data())) + ":";

    break;

  case PushData:

    text = string("data_") + toHex(data());

    break;

  case PushSub:

  case PushSubSize:

  {

    vector<string> subPathComponents;

    for (size_t subPathComponentId: _assembly.decodeSubPath(static_cast<size_t>(data())))

      subPathComponents.emplace_back("sub_" + to_string(subPathComponentId));

    text =

      (type() == PushSub ? "dataOffset"s : "dataSize"s) +

      "(" +

      solidity::util::joinHumanReadable(subPathComponents, ".") +

      ")";

    break;

  }

  case PushProgramSize:

    text = string("bytecodeSize");

    break;

  case PushLibraryAddress:

    text = string("linkerSymbol(\"") + toHex(data()) + string("\")");

    break;

  case PushDeployTimeAddress:

    text = string("deployTimeAddress()");

    break;

  case PushImmutable:

    text = string("immutable(\"") + "0x" + util::toHex(toCompactBigEndian(data(), 1)) + "\")";

    break;

  case AssignImmutable:

    text = string("assignImmutable(\"") + "0x" + util::toHex(toCompactBigEndian(data(), 1)) + "\")";

    break;

  case UndefinedItem:

    assertThrow(false, AssemblyException, "Invalid assembly item.");

    break;

  case VerbatimBytecode:

    text = string("verbatimbytecode_") + util::toHex(get<2>(*m_verbatimBytecode));

    break;

  default:

    assertThrow(false, InvalidOpcode, "");

  }

  if (m_jumpType == JumpType::IntoFunction || m_jumpType == JumpType::OutOfFunction)

  {

    text += "\t//";

    if (m_jumpType == JumpType::IntoFunction)

      text += " in";

    else

      text += " out";

  }

  return text;

}

ostream& solidity::evmasm::operator<<(ostream& _out, AssemblyItem const& _item)

{

  switch (_item.type())

  {

  case Operation:

    _out << " " << instructionInfo(_item.instruction()).name;

    if (_item.instruction() == Instruction::JUMP || _item.instruction() == Instruction::JUMPI)

      _out << "\t" << _item.getJumpTypeAsString();

    break;

  case Push:

    _out << " PUSH " << hex << _item.data() << dec;

    break;

  case PushTag:

  {

    size_t subId = _item.splitForeignPushTag().first;

    if (subId == numeric_limits<size_t>::max())

      _out << " PushTag " << _item.splitForeignPushTag().second;

    else

      _out << " PushTag " << subId << ":" << _item.splitForeignPushTag().second;

    break;

  }

  case Tag:

    _out << " Tag " << _item.data();

    break;

  case PushData:

    _out << " PushData " << hex << static_cast<unsigned>(_item.data()) << dec;

    break;

  case PushSub:

    _out << " PushSub " << hex << static_cast<size_t>(_item.data()) << dec;

    break;

  case PushSubSize:

    _out << " PushSubSize " << hex << static_cast<size_t>(_item.data()) << dec;

    break;

  case PushProgramSize:

    _out << " PushProgramSize";

    break;

  case PushLibraryAddress:

  {

    string hash(util::h256((_item.data())).hex());

    _out << " PushLibraryAddress " << hash.substr(0, 8) + "..." + hash.substr(hash.length() - 8);

    break;

  }

  case PushDeployTimeAddress:

    _out << " PushDeployTimeAddress";

    break;

  case PushImmutable:

    _out << " PushImmutable";

    break;

  case AssignImmutable:

    _out << " AssignImmutable";

    break;

  case VerbatimBytecode:

    _out << " Verbatim " << util::toHex(_item.verbatimData());

    break;

  case UndefinedItem:

    _out << " ???";

    break;

  default:

    assertThrow(false, InvalidOpcode, "");

  }

  return _out;

}

size_t AssemblyItem::opcodeCount() const noexcept

{

  switch (m_type)

  {

    case AssemblyItemType::AssignImmutable:

      // Append empty items if this AssignImmutable was referenced more than once.

      // For n immutable occurrences the first (n - 1) occurrences will

      // generate 5 opcodes and the last will generate 3 opcodes,

      // because it is reusing the 2 top-most elements on the stack.

      solAssert(m_immutableOccurrences, "");

      if (m_immutableOccurrences.value() != 0)

        return (*m_immutableOccurrences - 1) * 5 + 3;

      else

        return 2; // two POP's

    default:

      return 1;

  }

}

std::string AssemblyItem::computeSourceMapping(

  AssemblyItems const& _items,

  map<string, unsigned> const& _sourceIndicesMap

)

{

  string ret;

  int prevStart = -1;

  int prevLength = -1;

  int prevSourceIndex = -1;

  int prevModifierDepth = -1;

  char prevJump = 0;

  for (auto const& item: _items)

  {

    if (!ret.empty())

      ret += ";";

    SourceLocation const& location = item.location();

    int length = location.start != -1 && location.end != -1 ? location.end - location.start : -1;

    int sourceIndex =

      (location.sourceName && _sourceIndicesMap.count(*location.sourceName)) ?

      static_cast<int>(_sourceIndicesMap.at(*location.sourceName)) :

      -1;

    char jump = '-';

    if (item.getJumpType() == evmasm::AssemblyItem::JumpType::IntoFunction)

      jump = 'i';

    else if (item.getJumpType() == evmasm::AssemblyItem::JumpType::OutOfFunction)

      jump = 'o';

    int modifierDepth = static_cast<int>(item.m_modifierDepth);

    unsigned components = 5;

    if (modifierDepth == prevModifierDepth)

    {

      components--;

      if (jump == prevJump)

      {

        components--;

        if (sourceIndex == prevSourceIndex)

        {

          components--;

          if (length == prevLength)

          {

            components--;

            if (location.start == prevStart)

              components--;

          }

        }

      }

    }

    if (components-- > 0)

    {

      if (location.start != prevStart)

        ret += to_string(location.start);

      if (components-- > 0)

      {

        ret += ':';

        if (length != prevLength)

          ret += to_string(length);

        if (components-- > 0)

        {

          ret += ':';

          if (sourceIndex != prevSourceIndex)

            ret += to_string(sourceIndex);

          if (components-- > 0)

          {

            ret += ':';

            if (jump != prevJump)

              ret += jump;

            if (components-- > 0)

            {

              ret += ':';

              if (modifierDepth != prevModifierDepth)

                ret += to_string(modifierDepth);

            }

          }

        }

      }

    }

    if (item.opcodeCount() > 1)

      ret += string(item.opcodeCount() - 1, ';');

    prevStart = location.start;

    prevLength = length;

    prevSourceIndex = sourceIndex;

    prevJump = jump;

    prevModifierDepth = modifierDepth;

  }

  return ret;

}