/src/solidity/libsolidity/codegen/ABIFunctions.cpp

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/*
  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
/**
 * @author Christian <chris@ethereum.org>
 * @date 2017
 * Routines that generate Yul code related to ABI encoding, decoding and type conversions.
 */

#include <libsolidity/codegen/ABIFunctions.h>

#include <libsolidity/codegen/CompilerUtils.h>
#include <libsolutil/CommonData.h>
#include <libsolutil/Whiskers.h>
#include <libsolutil/StringUtils.h>

#include <boost/algorithm/string/join.hpp>

using namespace solidity;
using namespace solidity::util;
using namespace solidity::frontend;

std::string ABIFunctions::tupleEncoder(
  TypePointers const& _givenTypes,
  TypePointers _targetTypes,
  bool _encodeAsLibraryTypes,
  bool _reversed
)
{
  solAssert(_givenTypes.size() == _targetTypes.size(), "");
  EncodingOptions options;
  options.encodeAsLibraryTypes = _encodeAsLibraryTypes;
  options.encodeFunctionFromStack = true;
  options.padded = true;
  options.dynamicInplace = false;

  for (Type const*& t: _targetTypes)
  {
    solAssert(t, "");
    t = t->fullEncodingType(options.encodeAsLibraryTypes, true, !options.padded);
    solAssert(t, "");
  }

  std::string functionName = std::string("abi_encode_tuple_");
  for (auto const& t: _givenTypes)
    functionName += t->identifier() + "_";
  functionName += "_to_";
  for (auto const& t: _targetTypes)
    functionName += t->identifier() + "_";
  functionName += options.toFunctionNameSuffix();
  if (_reversed)
    functionName += "_reversed";

  return createFunction(functionName, [&]() {
    // Note that the values are in reverse due to the difference in calling semantics.
    Whiskers templ(R"(
      function <functionName>(headStart <valueParams>) -> tail {
        tail := add(headStart, <headSize>)
        <encodeElements>
      }
    )");
    templ("functionName", functionName);
    size_t const headSize_ = headSize(_targetTypes);
    templ("headSize", std::to_string(headSize_));
    std::string encodeElements;
    size_t headPos = 0;
    size_t stackPos = 0;
    for (size_t i = 0; i < _givenTypes.size(); ++i)
    {
      solAssert(_givenTypes[i], "");
      solAssert(_targetTypes[i], "");
      size_t sizeOnStack = _givenTypes[i]->sizeOnStack();
      bool dynamic = _targetTypes[i]->isDynamicallyEncoded();
      Whiskers elementTempl(
        dynamic ?
        std::string(R"(
          mstore(add(headStart, <pos>), sub(tail, headStart))
          tail := <abiEncode>(<values> tail)
        )") :
        std::string(R"(
          <abiEncode>(<values> add(headStart, <pos>))
        )")
      );
      std::string values = suffixedVariableNameList("value", stackPos, stackPos + sizeOnStack);
      elementTempl("values", values.empty() ? "" : values + ", ");
      elementTempl("pos", std::to_string(headPos));
      elementTempl("abiEncode", abiEncodingFunction(*_givenTypes[i], *_targetTypes[i], options));
      encodeElements += elementTempl.render();
      headPos += _targetTypes[i]->calldataHeadSize();
      stackPos += sizeOnStack;
    }
    solAssert(headPos == headSize_, "");
    std::string valueParams =
      _reversed ?
      suffixedVariableNameList("value", stackPos, 0) :
      suffixedVariableNameList("value", 0, stackPos);
    templ("valueParams", valueParams.empty() ? "" : ", " + valueParams);
    templ("encodeElements", encodeElements);

    return templ.render();
  });
}

std::string ABIFunctions::tupleEncoderPacked(
  TypePointers const& _givenTypes,
  TypePointers _targetTypes,
  bool _reversed
)
{
  EncodingOptions options;
  options.encodeAsLibraryTypes = false;
  options.encodeFunctionFromStack = true;
  options.padded = false;
  options.dynamicInplace = true;

  for (Type const*& t: _targetTypes)
  {
    solAssert(t, "");
    t = t->fullEncodingType(options.encodeAsLibraryTypes, true, !options.padded);
    solAssert(t, "");
  }

  std::string functionName = std::string("abi_encode_tuple_packed_");
  for (auto const& t: _givenTypes)
    functionName += t->identifier() + "_";
  functionName += "_to_";
  for (auto const& t: _targetTypes)
    functionName += t->identifier() + "_";
  functionName += options.toFunctionNameSuffix();
  if (_reversed)
    functionName += "_reversed";

  return createFunction(functionName, [&]() {
    // Note that the values are in reverse due to the difference in calling semantics.
    Whiskers templ(R"(
      function <functionName>(pos <valueParams>) -> end {
        <encodeElements>
        end := pos
      }
    )");
    templ("functionName", functionName);
    std::string encodeElements;
    size_t stackPos = 0;
    for (size_t i = 0; i < _givenTypes.size(); ++i)
    {
      solAssert(_givenTypes[i], "");
      solAssert(_targetTypes[i], "");
      size_t sizeOnStack = _givenTypes[i]->sizeOnStack();
      bool dynamic = _targetTypes[i]->isDynamicallyEncoded();
      Whiskers elementTempl(
        dynamic ?
        std::string(R"(
          pos := <abiEncode>(<values> pos)
        )") :
        std::string(R"(
          <abiEncode>(<values> pos)
          pos := add(pos, <calldataEncodedSize>)
        )")
      );
      std::string values = suffixedVariableNameList("value", stackPos, stackPos + sizeOnStack);
      elementTempl("values", values.empty() ? "" : values + ", ");
      if (!dynamic)
        elementTempl("calldataEncodedSize", std::to_string(_targetTypes[i]->calldataEncodedSize(false)));
      elementTempl("abiEncode", abiEncodingFunction(*_givenTypes[i], *_targetTypes[i], options));
      encodeElements += elementTempl.render();
      stackPos += sizeOnStack;
    }
    std::string valueParams =
      _reversed ?
      suffixedVariableNameList("value", stackPos, 0) :
      suffixedVariableNameList("value", 0, stackPos);
    templ("valueParams", valueParams.empty() ? "" : ", " + valueParams);
    templ("encodeElements", encodeElements);

    return templ.render();
  });
}
std::string ABIFunctions::tupleDecoder(TypePointers const& _types, bool _fromMemory)
{
  std::string functionName = std::string("abi_decode_tuple_");
  for (auto const& t: _types)
    functionName += t->identifier();
  if (_fromMemory)
    functionName += "_fromMemory";

  return createFunction(functionName, [&]() {
    TypePointers decodingTypes;
    for (auto const& t: _types)
      decodingTypes.emplace_back(t->decodingType());

    Whiskers templ(R"(
      function <functionName>(headStart, dataEnd) <arrow> <valueReturnParams> {
        if slt(sub(dataEnd, headStart), <minimumSize>) { <revertString>() }
        <decodeElements>
      }
    )");
    templ("functionName", functionName);
    templ("revertString", revertReasonIfDebugFunction("ABI decoding: tuple data too short"));
    templ("minimumSize", std::to_string(headSize(decodingTypes)));

    std::string decodeElements;
    std::vector<std::string> valueReturnParams;
    size_t headPos = 0;
    size_t stackPos = 0;
    for (size_t i = 0; i < _types.size(); ++i)
    {
      solAssert(_types[i], "");
      solAssert(decodingTypes[i], "");
      size_t sizeOnStack = _types[i]->sizeOnStack();
      solAssert(sizeOnStack == decodingTypes[i]->sizeOnStack(), "");
      solAssert(sizeOnStack > 0, "");
      std::vector<std::string> valueNamesLocal;
      for (size_t j = 0; j < sizeOnStack; j++)
      {
        valueNamesLocal.emplace_back("value" + std::to_string(stackPos));
        valueReturnParams.emplace_back("value" + std::to_string(stackPos));
        stackPos++;
      }
      Whiskers elementTempl(R"(
        {
          <?dynamic>
            let offset := <load>(add(headStart, <pos>))
            if gt(offset, 0xffffffffffffffff) { <revertString>() }
          <!dynamic>
            let offset := <pos>
          </dynamic>
          <values> := <abiDecode>(add(headStart, offset), dataEnd)
        }
      )");
      elementTempl("dynamic", decodingTypes[i]->isDynamicallyEncoded());
      // TODO add test
      elementTempl("revertString", revertReasonIfDebugFunction("ABI decoding: invalid tuple offset"));
      elementTempl("load", _fromMemory ? "mload" : "calldataload");
      elementTempl("values", boost::algorithm::join(valueNamesLocal, ", "));
      elementTempl("pos", std::to_string(headPos));
      elementTempl("abiDecode", abiDecodingFunction(*_types[i], _fromMemory, true));
      decodeElements += elementTempl.render();
      headPos += decodingTypes[i]->calldataHeadSize();
    }
    templ("valueReturnParams", boost::algorithm::join(valueReturnParams, ", "));
    templ("arrow", valueReturnParams.empty() ? "" : "->");
    templ("decodeElements", decodeElements);

    return templ.render();
  });
}

std::string ABIFunctions::EncodingOptions::toFunctionNameSuffix() const
{
  std::string suffix;
  if (!padded)
    suffix += "_nonPadded";
  if (dynamicInplace)
    suffix += "_inplace";
  if (encodeFunctionFromStack)
    suffix += "_fromStack";
  if (encodeAsLibraryTypes)
    suffix += "_library";
  return suffix;
}

std::string ABIFunctions::abiEncodingFunction(
  Type const& _from,
  Type const& _to,
  EncodingOptions const& _options
)
{
  Type const* toInterface = _to.fullEncodingType(_options.encodeAsLibraryTypes, true, false);
  solUnimplementedAssert(toInterface, "Encoding type \"" + _to.toString() + "\" not yet implemented.");
  Type const& to = *toInterface;

  if (_from.category() == Type::Category::StringLiteral)
    return abiEncodingFunctionStringLiteral(_from, to, _options);
  else if (auto toArray = dynamic_cast<ArrayType const*>(&to))
  {
    ArrayType const* fromArray = nullptr;
    switch (_from.category())
    {
      case Type::Category::Array:
        fromArray = dynamic_cast<ArrayType const*>(&_from);
        break;
      case Type::Category::ArraySlice:
        fromArray = &dynamic_cast<ArraySliceType const*>(&_from)->arrayType();
        solAssert(
          fromArray->dataStoredIn(DataLocation::CallData) &&
          fromArray->isDynamicallySized() &&
          !fromArray->baseType()->isDynamicallyEncoded(),
          ""
        );
        break;
      default:
        solAssert(false, "");
        break;
    }

    switch (fromArray->location())
    {
      case DataLocation::CallData:
        if (
          fromArray->isByteArrayOrString() ||
          *fromArray->baseType() == *TypeProvider::uint256() ||
          *fromArray->baseType() == FixedBytesType(32)
        )
          return abiEncodingFunctionCalldataArrayWithoutCleanup(*fromArray, *toArray, _options);
        else
          return abiEncodingFunctionSimpleArray(*fromArray, *toArray, _options);
      case DataLocation::Memory:
        if (fromArray->isByteArrayOrString())
          return abiEncodingFunctionMemoryByteArray(*fromArray, *toArray, _options);
        else
          return abiEncodingFunctionSimpleArray(*fromArray, *toArray, _options);
      case DataLocation::Storage:
        if (fromArray->baseType()->storageBytes() <= 16)
          return abiEncodingFunctionCompactStorageArray(*fromArray, *toArray, _options);
        else
          return abiEncodingFunctionSimpleArray(*fromArray, *toArray, _options);
      default:
        solAssert(false, "");
    }
  }
  else if (auto const* toStruct = dynamic_cast<StructType const*>(&to))
  {
    StructType const* fromStruct = dynamic_cast<StructType const*>(&_from);
    solAssert(fromStruct, "");
    return abiEncodingFunctionStruct(*fromStruct, *toStruct, _options);
  }
  else if (_from.category() == Type::Category::Function)
    return abiEncodingFunctionFunctionType(
      dynamic_cast<FunctionType const&>(_from),
      to,
      _options
    );

  solAssert(_from.sizeOnStack() == 1, "");
  solAssert(to.isValueType(), "");
  solAssert(to.calldataEncodedSize() == 32, "");
  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    to.identifier() +
    _options.toFunctionNameSuffix();
  return createFunction(functionName, [&]() {
    solAssert(!to.isDynamicallyEncoded(), "");

    Whiskers templ(R"(
      function <functionName>(value, pos) {
        mstore(pos, <cleanupConvert>)
      }
    )");
    templ("functionName", functionName);

    if (_from.dataStoredIn(DataLocation::Storage))
    {
      // special case: convert storage reference type to value type - this is only
      // possible for library calls where we just forward the storage reference
      solAssert(_options.encodeAsLibraryTypes, "");
      solAssert(_options.padded && !_options.dynamicInplace, "Non-padded / inplace encoding for library call requested.");
      solAssert(to == *TypeProvider::uint256(), "");
      templ("cleanupConvert", "value");
    }
    else
    {
      std::string cleanupConvert;
      if (_from == to)
        cleanupConvert = m_utils.cleanupFunction(_from) + "(value)";
      else
        cleanupConvert = m_utils.conversionFunction(_from, to) + "(value)";
      if (!_options.padded)
        cleanupConvert = m_utils.leftAlignFunction(to) + "(" + cleanupConvert + ")";
      templ("cleanupConvert", cleanupConvert);
    }
    return templ.render();
  });
}

std::string ABIFunctions::abiEncodeAndReturnUpdatedPosFunction(
  Type const& _givenType,
  Type const& _targetType,
  ABIFunctions::EncodingOptions const& _options
)
{
  std::string functionName =
    "abi_encodeUpdatedPos_" +
    _givenType.identifier() +
    "_to_" +
    _targetType.identifier() +
    _options.toFunctionNameSuffix();
  return createFunction(functionName, [&]() {
    std::string values = suffixedVariableNameList("value", 0, numVariablesForType(_givenType, _options));
    std::string encoder = abiEncodingFunction(_givenType, _targetType, _options);
    Type const* targetEncoding = _targetType.fullEncodingType(_options.encodeAsLibraryTypes, true, false);
    solAssert(targetEncoding, "");
    if (targetEncoding->isDynamicallyEncoded())
      return Whiskers(R"(
        function <functionName>(<values>, pos) -> updatedPos {
          updatedPos := <encode>(<values>, pos)
        }
      )")
      ("functionName", functionName)
      ("encode", encoder)
      ("values", values)
      .render();
    else
    {
      unsigned encodedSize = targetEncoding->calldataEncodedSize(_options.padded);
      solAssert(encodedSize != 0, "Invalid encoded size.");
      return Whiskers(R"(
        function <functionName>(<values>, pos) -> updatedPos {
          <encode>(<values>, pos)
          updatedPos := add(pos, <encodedSize>)
        }
      )")
      ("functionName", functionName)
      ("encode", encoder)
      ("encodedSize", toCompactHexWithPrefix(encodedSize))
      ("values", values)
      .render();
    }
  });
}

std::string ABIFunctions::abiEncodingFunctionCalldataArrayWithoutCleanup(
  Type const& _from,
  Type const& _to,
  EncodingOptions const& _options
)
{
  solAssert(_from.category() == Type::Category::Array, "Unknown dynamic type.");
  solAssert(_to.category() == Type::Category::Array, "Unknown dynamic type.");
  auto const& fromArrayType = dynamic_cast<ArrayType const&>(_from);
  auto const& toArrayType = dynamic_cast<ArrayType const&>(_to);

  solAssert(fromArrayType.location() == DataLocation::CallData, "");
  solAssert(
    fromArrayType.isByteArrayOrString() ||
    *fromArrayType.baseType() == *TypeProvider::uint256() ||
    *fromArrayType.baseType() == FixedBytesType(32),
    ""
  );
  solAssert(fromArrayType.calldataStride() == toArrayType.memoryStride(), "");

  solAssert(
    *fromArrayType.copyForLocation(DataLocation::Memory, true) ==
    *toArrayType.copyForLocation(DataLocation::Memory, true),
    ""
  );

  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();
  return createFunction(functionName, [&]() {
    bool bytesOrString = fromArrayType.isByteArrayOrString();
    bool needsPadding = _options.padded && bytesOrString;
    if (fromArrayType.isDynamicallySized())
    {
      Whiskers templ(R"(
        // <readableTypeNameFrom> -> <readableTypeNameTo>
        function <functionName>(start, length, pos) -> end {
          pos := <storeLength>(pos, length)
          <scaleLengthByStride>
          <copyFun>(start, pos, length)
          end := add(pos, <lengthPadded>)
        }
      )");
      templ("storeLength", arrayStoreLengthForEncodingFunction(toArrayType, _options));
      templ("functionName", functionName);
      if (fromArrayType.isByteArrayOrString() || fromArrayType.calldataStride() == 1)
        templ("scaleLengthByStride", "");
      else
        templ("scaleLengthByStride",
          Whiskers(R"(
            if gt(length, <maxLength>) { <revertString>() }
            length := mul(length, <stride>)
          )")
          ("stride", toCompactHexWithPrefix(fromArrayType.calldataStride()))
          ("maxLength", toCompactHexWithPrefix(u256(-1) / fromArrayType.calldataStride()))
          ("revertString", revertReasonIfDebugFunction("ABI encoding: array data too long"))
          .render()
          // TODO add revert test
        );
      templ("readableTypeNameFrom", _from.toString(true));
      templ("readableTypeNameTo", _to.toString(true));
      templ("copyFun", m_utils.copyToMemoryFunction(true, /*cleanup*/bytesOrString));
      templ("lengthPadded", needsPadding ? m_utils.roundUpFunction() + "(length)" : "length");
      return templ.render();
    }
    else
    {
      solAssert(fromArrayType.calldataStride() == 32, "");
      Whiskers templ(R"(
        // <readableTypeNameFrom> -> <readableTypeNameTo>
        function <functionName>(start, pos) {
          <copyFun>(start, pos, <byteLength>)
        }
      )");
      templ("functionName", functionName);
      templ("readableTypeNameFrom", _from.toString(true));
      templ("readableTypeNameTo", _to.toString(true));
      templ("copyFun", m_utils.copyToMemoryFunction(true, /*cleanup*/bytesOrString));
      templ("byteLength", toCompactHexWithPrefix(fromArrayType.length() * fromArrayType.calldataStride()));
      return templ.render();
    }
  });
}

std::string ABIFunctions::abiEncodingFunctionSimpleArray(
  ArrayType const& _from,
  ArrayType const& _to,
  EncodingOptions const& _options
)
{
  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();

  solAssert(_from.isDynamicallySized() == _to.isDynamicallySized(), "");
  solAssert(_from.length() == _to.length(), "");
  solAssert(!_from.isByteArrayOrString(), "");
  if (_from.dataStoredIn(DataLocation::Storage))
    solAssert(_from.baseType()->storageBytes() > 16, "");

  return createFunction(functionName, [&]() {
    bool dynamic = _to.isDynamicallyEncoded();
    bool dynamicBase = _to.baseType()->isDynamicallyEncoded();
    bool const usesTail = dynamicBase && !_options.dynamicInplace;
    EncodingOptions subOptions(_options);
    subOptions.encodeFunctionFromStack = false;
    subOptions.padded = true;
    std::string elementValues = suffixedVariableNameList("elementValue", 0, numVariablesForType(*_from.baseType(), subOptions));
    Whiskers templ(
      usesTail ?
      R"(
        // <readableTypeNameFrom> -> <readableTypeNameTo>
        function <functionName>(value,<maybeLength> pos) <return> {
          <declareLength>
          pos := <storeLength>(pos, length)
          let headStart := pos
          let tail := add(pos, mul(length, 0x20))
          let baseRef := <dataAreaFun>(value)
          let srcPtr := baseRef
          for { let i := 0 } lt(i, length) { i := add(i, 1) }
          {
            mstore(pos, sub(tail, headStart))
            let <elementValues> := <arrayElementAccess>
            tail := <encodeToMemoryFun>(<elementValues>, tail)
            srcPtr := <nextArrayElement>(srcPtr)
            pos := add(pos, 0x20)
          }
          pos := tail
          <assignEnd>
        }
      )" :
      R"(
        // <readableTypeNameFrom> -> <readableTypeNameTo>
        function <functionName>(value,<maybeLength> pos) <return> {
          <declareLength>
          pos := <storeLength>(pos, length)
          let baseRef := <dataAreaFun>(value)
          let srcPtr := baseRef
          for { let i := 0 } lt(i, length) { i := add(i, 1) }
          {
            let <elementValues> := <arrayElementAccess>
            pos := <encodeToMemoryFun>(<elementValues>, pos)
            srcPtr := <nextArrayElement>(srcPtr)
          }
          <assignEnd>
        }
      )"
    );
    templ("functionName", functionName);
    templ("elementValues", elementValues);
    bool lengthAsArgument = _from.dataStoredIn(DataLocation::CallData) && _from.isDynamicallySized();
    if (lengthAsArgument)
    {
      templ("maybeLength", " length,");
      templ("declareLength", "");
    }
    else
    {
      templ("maybeLength", "");
      templ("declareLength", "let length := " + m_utils.arrayLengthFunction(_from) + "(value)");
    }
    templ("readableTypeNameFrom", _from.toString(true));
    templ("readableTypeNameTo", _to.toString(true));
    templ("return", dynamic ? " -> end " : "");
    templ("assignEnd", dynamic ? "end := pos" : "");
    templ("storeLength", arrayStoreLengthForEncodingFunction(_to, _options));
    templ("dataAreaFun", m_utils.arrayDataAreaFunction(_from));

    templ("encodeToMemoryFun", abiEncodeAndReturnUpdatedPosFunction(*_from.baseType(), *_to.baseType(), subOptions));
    switch (_from.location())
    {
      case DataLocation::Memory:
        templ("arrayElementAccess", "mload(srcPtr)");
        break;
      case DataLocation::Storage:
        if (_from.baseType()->isValueType())
          templ("arrayElementAccess", m_utils.readFromStorage(*_from.baseType(), 0, false, VariableDeclaration::Location::Unspecified) + "(srcPtr)");
        else
          templ("arrayElementAccess", "srcPtr");
        break;
      case DataLocation::CallData:
        templ("arrayElementAccess", calldataAccessFunction(*_from.baseType()) + "(baseRef, srcPtr)");
        break;
      default:
        solAssert(false, "");
    }
    templ("nextArrayElement", m_utils.nextArrayElementFunction(_from));
    return templ.render();
  });
}

std::string ABIFunctions::abiEncodingFunctionMemoryByteArray(
  ArrayType const& _from,
  ArrayType const& _to,
  EncodingOptions const& _options
)
{
  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();

  solAssert(_from.isDynamicallySized() == _to.isDynamicallySized(), "");
  solAssert(_from.length() == _to.length(), "");
  solAssert(_from.dataStoredIn(DataLocation::Memory), "");
  solAssert(_from.isByteArrayOrString(), "");

  return createFunction(functionName, [&]() {
    solAssert(_to.isByteArrayOrString(), "");
    Whiskers templ(R"(
      function <functionName>(value, pos) -> end {
        let length := <lengthFun>(value)
        pos := <storeLength>(pos, length)
        <copyFun>(add(value, 0x20), pos, length)
        end := add(pos, <lengthPadded>)
      }
    )");
    templ("functionName", functionName);
    templ("lengthFun", m_utils.arrayLengthFunction(_from));
    templ("storeLength", arrayStoreLengthForEncodingFunction(_to, _options));
    templ("copyFun", m_utils.copyToMemoryFunction(false, /*cleanup*/true));
    templ("lengthPadded", _options.padded ? m_utils.roundUpFunction() + "(length)" : "length");
    return templ.render();
  });
}

std::string ABIFunctions::abiEncodingFunctionCompactStorageArray(
  ArrayType const& _from,
  ArrayType const& _to,
  EncodingOptions const& _options
)
{
  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();

  solAssert(_from.isDynamicallySized() == _to.isDynamicallySized(), "");
  solAssert(_from.length() == _to.length(), "");
  solAssert(_from.dataStoredIn(DataLocation::Storage), "");

  return createFunction(functionName, [&]() {
    if (_from.isByteArrayOrString())
    {
      solAssert(_to.isByteArrayOrString(), "");
      Whiskers templ(R"(
        // <readableTypeNameFrom> -> <readableTypeNameTo>
        function <functionName>(value, pos) -> ret {
          let slotValue := sload(value)
          let length := <byteArrayLengthFunction>(slotValue)
          pos := <storeLength>(pos, length)
          switch and(slotValue, 1)
          case 0 {
            // short byte array
            mstore(pos, and(slotValue, not(0xff)))
            ret := add(pos, mul(<lengthPaddedShort>, iszero(iszero(length))))
          }
          case 1 {
            // long byte array
            let dataPos := <arrayDataSlot>(value)
            let i := 0
            for { } lt(i, length) { i := add(i, 0x20) } {
              mstore(add(pos, i), sload(dataPos))
              dataPos := add(dataPos, 1)
            }
            ret := add(pos, <lengthPaddedLong>)
          }
        }
      )");
      templ("functionName", functionName);
      templ("readableTypeNameFrom", _from.toString(true));
      templ("readableTypeNameTo", _to.toString(true));
      templ("byteArrayLengthFunction", m_utils.extractByteArrayLengthFunction());
      templ("storeLength", arrayStoreLengthForEncodingFunction(_to, _options));
      templ("lengthPaddedShort", _options.padded ? "0x20" : "length");
      templ("lengthPaddedLong", _options.padded ? "i" : "length");
      templ("arrayDataSlot", m_utils.arrayDataAreaFunction(_from));
      return templ.render();
    }
    else
    {
      // Multiple items per slot
      solAssert(_from.baseType()->storageBytes() <= 16, "");
      solAssert(!_from.baseType()->isDynamicallyEncoded(), "");
      solAssert(!_to.baseType()->isDynamicallyEncoded(), "");
      solAssert(_from.baseType()->isValueType(), "");
      bool dynamic = _to.isDynamicallyEncoded();
      size_t storageBytes = _from.baseType()->storageBytes();
      size_t itemsPerSlot = 32 / storageBytes;
      solAssert(itemsPerSlot > 0, "");
      // The number of elements we need to handle manually after the loop.
      size_t spill = static_cast<size_t>(_from.length() % itemsPerSlot);
      Whiskers templ(
        R"(
          // <readableTypeNameFrom> -> <readableTypeNameTo>
          function <functionName>(value, pos) <return> {
            let length := <lengthFun>(value)
            pos := <storeLength>(pos, length)
            let originalPos := pos
            let srcPtr := <dataArea>(value)
            let itemCounter := 0
            if <useLoop> {
              // Run the loop over all full slots
              for { } lt(add(itemCounter, sub(<itemsPerSlot>, 1)), length)
                    { itemCounter := add(itemCounter, <itemsPerSlot>) }
              {
                let data := sload(srcPtr)
                <#items>
                  <encodeToMemoryFun>(<extractFromSlot>(data), pos)
                  pos := add(pos, <stride>)
                </items>
                srcPtr := add(srcPtr, 1)
              }
            }
            // Handle the last (not necessarily full) slot specially
            if <useSpill> {
              let data := sload(srcPtr)
              <#items>
                if <inRange> {
                  <encodeToMemoryFun>(<extractFromSlot>(data), pos)
                  pos := add(pos, <stride>)
                  itemCounter := add(itemCounter, 1)
                }
              </items>
            }
            <assignEnd>
          }
        )"
      );
      templ("functionName", functionName);
      templ("readableTypeNameFrom", _from.toString(true));
      templ("readableTypeNameTo", _to.toString(true));
      templ("return", dynamic ? " -> end " : "");
      templ("assignEnd", dynamic ? "end := pos" : "");
      templ("lengthFun", m_utils.arrayLengthFunction(_from));
      templ("storeLength", arrayStoreLengthForEncodingFunction(_to, _options));
      templ("dataArea", m_utils.arrayDataAreaFunction(_from));
      // We skip the loop for arrays that fit a single slot.
      if (_from.isDynamicallySized() || _from.length() >= itemsPerSlot)
        templ("useLoop", "1");
      else
        templ("useLoop", "0");
      if (_from.isDynamicallySized() || spill != 0)
        templ("useSpill", "1");
      else
        templ("useSpill", "0");
      templ("itemsPerSlot", std::to_string(itemsPerSlot));
      templ("stride", toCompactHexWithPrefix(_to.calldataStride()));

      EncodingOptions subOptions(_options);
      subOptions.encodeFunctionFromStack = false;
      subOptions.padded = true;
      std::string encodeToMemoryFun = abiEncodingFunction(
        *_from.baseType(),
        *_to.baseType(),
        subOptions
      );
      templ("encodeToMemoryFun", encodeToMemoryFun);
      std::vector<std::map<std::string, std::string>> items(itemsPerSlot);
      for (size_t i = 0; i < itemsPerSlot; ++i)
      {
        if (_from.isDynamicallySized())
          items[i]["inRange"] = "lt(itemCounter, length)";
        else if (i < spill)
          items[i]["inRange"] = "1";
        else
          items[i]["inRange"] = "0";
        items[i]["extractFromSlot"] = m_utils.extractFromStorageValue(*_from.baseType(), i * storageBytes);
      }
      templ("items", items);
      return templ.render();
    }
  });
}

std::string ABIFunctions::abiEncodingFunctionStruct(
  StructType const& _from,
  StructType const& _to,
  EncodingOptions const& _options
)
{
  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();

  solAssert(&_from.structDefinition() == &_to.structDefinition(), "");

  return createFunction(functionName, [&]() {
    bool dynamic = _to.isDynamicallyEncoded();
    Whiskers templ(R"(
      // <readableTypeNameFrom> -> <readableTypeNameTo>
      function <functionName>(value, pos) <return> {
        let tail := add(pos, <headSize>)
        <init>
        <#members>
        {
          // <memberName>
          <preprocess>
          let <memberValues> := <retrieveValue>
          <encode>
        }
        </members>
        <assignEnd>
      }
    )");
    templ("functionName", functionName);
    templ("readableTypeNameFrom", _from.toString(true));
    templ("readableTypeNameTo", _to.toString(true));
    templ("return", dynamic ? " -> end " : "");
    if (dynamic && _options.dynamicInplace)
      templ("assignEnd", "end := pos");
    else if (dynamic && !_options.dynamicInplace)
      templ("assignEnd", "end := tail");
    else
      templ("assignEnd", "");
    // to avoid multiple loads from the same slot for subsequent members
    templ("init", _from.dataStoredIn(DataLocation::Storage) ? "let slotValue := 0" : "");
    u256 previousSlotOffset(-1);
    u256 encodingOffset = 0;
    std::vector<std::map<std::string, std::string>> members;
    for (auto const& member: _to.members(nullptr))
    {
      solAssert(member.type, "");
      solAssert(!member.type->containsNestedMapping(), "");
      Type const* memberTypeTo = member.type->fullEncodingType(_options.encodeAsLibraryTypes, true, false);
      solUnimplementedAssert(memberTypeTo, "Encoding type \"" + member.type->toString() + "\" not yet implemented.");
      auto memberTypeFrom = _from.memberType(member.name);
      solAssert(memberTypeFrom, "");
      bool dynamicMember = memberTypeTo->isDynamicallyEncoded();
      if (dynamicMember)
        solAssert(dynamic, "");

      members.emplace_back();
      members.back()["preprocess"] = "";

      switch (_from.location())
      {
        case DataLocation::Storage:
        {
          solAssert(memberTypeFrom->isValueType() == memberTypeTo->isValueType(), "");
          u256 storageSlotOffset;
          size_t intraSlotOffset;
          std::tie(storageSlotOffset, intraSlotOffset) = _from.storageOffsetsOfMember(member.name);
          if (memberTypeFrom->isValueType())
          {
            if (storageSlotOffset != previousSlotOffset)
            {
              members.back()["preprocess"] = "slotValue := sload(add(value, " + toCompactHexWithPrefix(storageSlotOffset) + "))";
              previousSlotOffset = storageSlotOffset;
            }
            members.back()["retrieveValue"] = m_utils.extractFromStorageValue(*memberTypeFrom, intraSlotOffset) + "(slotValue)";
          }
          else
          {
            solAssert(memberTypeFrom->dataStoredIn(DataLocation::Storage), "");
            solAssert(intraSlotOffset == 0, "");
            members.back()["retrieveValue"] = "add(value, " + toCompactHexWithPrefix(storageSlotOffset) + ")";
          }
          break;
        }
        case DataLocation::Memory:
        {
          std::string sourceOffset = toCompactHexWithPrefix(_from.memoryOffsetOfMember(member.name));
          members.back()["retrieveValue"] = "mload(add(value, " + sourceOffset + "))";
          break;
        }
        case DataLocation::CallData:
        {
          std::string sourceOffset = toCompactHexWithPrefix(_from.calldataOffsetOfMember(member.name));
          members.back()["retrieveValue"] = calldataAccessFunction(*memberTypeFrom) + "(value, add(value, " + sourceOffset + "))";
          break;
        }
        default:
          solAssert(false, "");
      }

      EncodingOptions subOptions(_options);
      subOptions.encodeFunctionFromStack = false;
      // Like with arrays, struct members are always padded.
      subOptions.padded = true;

      std::string memberValues = suffixedVariableNameList("memberValue", 0, numVariablesForType(*memberTypeFrom, subOptions));
      members.back()["memberValues"] = memberValues;

      std::string encode;
      if (_options.dynamicInplace)
        encode = Whiskers{"pos := <encode>(<memberValues>, pos)"}
          ("encode", abiEncodeAndReturnUpdatedPosFunction(*memberTypeFrom, *memberTypeTo, subOptions))
          ("memberValues", memberValues)
          .render();
      else
      {
        Whiskers encodeTempl(
          dynamicMember ?
          std::string(R"(
            mstore(add(pos, <encodingOffset>), sub(tail, pos))
            tail := <abiEncode>(<memberValues>, tail)
          )") :
          "<abiEncode>(<memberValues>, add(pos, <encodingOffset>))"
        );
        encodeTempl("memberValues", memberValues);
        encodeTempl("encodingOffset", toCompactHexWithPrefix(encodingOffset));
        encodingOffset += memberTypeTo->calldataHeadSize();
        encodeTempl("abiEncode", abiEncodingFunction(*memberTypeFrom, *memberTypeTo, subOptions));
        encode = encodeTempl.render();
      }
      members.back()["encode"] = encode;

      members.back()["memberName"] = member.name;
    }
    templ("members", members);
    if (_options.dynamicInplace)
      solAssert(encodingOffset == 0, "In-place encoding should enforce zero head size.");
    templ("headSize", toCompactHexWithPrefix(encodingOffset));
    return templ.render();
  });
}

std::string ABIFunctions::abiEncodingFunctionStringLiteral(
  Type const& _from,
  Type const& _to,
  EncodingOptions const& _options
)
{
  solAssert(_from.category() == Type::Category::StringLiteral, "");

  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();
  return createFunction(functionName, [&]() {
    auto const& strType = dynamic_cast<StringLiteralType const&>(_from);
    std::string const& value = strType.value();
    solAssert(_from.sizeOnStack() == 0, "");

    if (_to.isDynamicallySized())
    {
      solAssert(_to.category() == Type::Category::Array, "");
      Whiskers templ(R"(
        function <functionName>(pos) -> end {
          pos := <storeLength>(pos, <length>)
          <storeLiteralInMemory>(pos)
          end := add(pos, <overallSize>)
        }
      )");
      templ("functionName", functionName);

      // TODO this can make use of CODECOPY for large strings once we have that in Yul
      templ("length", std::to_string(value.size()));
      templ("storeLength", arrayStoreLengthForEncodingFunction(dynamic_cast<ArrayType const&>(_to), _options));
      if (_options.padded)
        templ("overallSize", std::to_string(((value.size() + 31) / 32) * 32));
      else
        templ("overallSize", std::to_string(value.size()));
      templ("storeLiteralInMemory", m_utils.storeLiteralInMemoryFunction(value));
      return templ.render();
    }
    else
    {
      solAssert(_to.category() == Type::Category::FixedBytes, "");
      solAssert(value.size() <= 32, "");
      Whiskers templ(R"(
        function <functionName>(pos) {
          mstore(pos, <wordValue>)
        }
      )");
      templ("functionName", functionName);
      templ("wordValue", formatAsStringOrNumber(value));
      return templ.render();
    }
  });
}

std::string ABIFunctions::abiEncodingFunctionFunctionType(
  FunctionType const& _from,
  Type const& _to,
  EncodingOptions const& _options
)
{
  solAssert(
    _from.kind() == FunctionType::Kind::External &&
    _from.isImplicitlyConvertibleTo(_to) &&
    _from.sizeOnStack() == _to.sizeOnStack(),
    "Invalid function type conversion requested"
  );

  std::string functionName =
    "abi_encode_" +
    _from.identifier() +
    "_to_" +
    _to.identifier() +
    _options.toFunctionNameSuffix();

  if (_options.encodeFunctionFromStack)
    return createFunction(functionName, [&]() {
      return Whiskers(R"(
        function <functionName>(addr, function_id, pos) {
          addr, function_id := <convert>(addr, function_id)
          mstore(pos, <combineExtFun>(addr, function_id))
        }
      )")
      ("functionName", functionName)
      ("combineExtFun", m_utils.combineExternalFunctionIdFunction())
      ("convert", m_utils.conversionFunction(_from, _to))
      .render();
    });
  else
    return createFunction(functionName, [&]() {
      return Whiskers(R"(
        function <functionName>(addr_and_function_id, pos) {
          mstore(pos, <cleanExtFun>(addr_and_function_id))
        }
      )")
      ("functionName", functionName)
      ("cleanExtFun", m_utils.cleanupFunction(_to))
      .render();
    });
}

std::string ABIFunctions::abiDecodingFunction(Type const& _type, bool _fromMemory, bool _forUseOnStack)
{
  // The decoding function has to perform bounds checks unless it decodes a value type.
  // Conversely, bounds checks have to be performed before the decoding function
  // of a value type is called.

  Type const* decodingType = _type.decodingType();
  solAssert(decodingType, "");

  if (auto arrayType = dynamic_cast<ArrayType const*>(decodingType))
  {
    if (arrayType->dataStoredIn(DataLocation::CallData))
    {
      solAssert(!_fromMemory, "");
      return abiDecodingFunctionCalldataArray(*arrayType);
    }
    else
      return abiDecodingFunctionArray(*arrayType, _fromMemory);
  }
  else if (auto const* structType = dynamic_cast<StructType const*>(decodingType))
  {
    if (structType->dataStoredIn(DataLocation::CallData))
    {
      solAssert(!_fromMemory, "");
      return abiDecodingFunctionCalldataStruct(*structType);
    }
    else
      return abiDecodingFunctionStruct(*structType, _fromMemory);
  }
  else if (auto const* functionType = dynamic_cast<FunctionType const*>(decodingType))
    return abiDecodingFunctionFunctionType(*functionType, _fromMemory, _forUseOnStack);
  else
    return abiDecodingFunctionValueType(_type, _fromMemory);
}

std::string ABIFunctions::abiDecodingFunctionValueType(Type const& _type, bool _fromMemory)
{
  Type const* decodingType = _type.decodingType();
  solAssert(decodingType, "");
  solAssert(decodingType->sizeOnStack() == 1, "");
  solAssert(decodingType->isValueType(), "");
  solAssert(!decodingType->isDynamicallyEncoded(), "");
  solAssert(decodingType->calldataEncodedSize() == 32, "");

  std::string functionName =
    "abi_decode_" +
    _type.identifier() +
    (_fromMemory ? "_fromMemory" : "");
  return createFunction(functionName, [&]() {
    Whiskers templ(R"(
      function <functionName>(offset, end) -> value {
        value := <load>(offset)
        <validator>(value)
      }
    )");
    templ("functionName", functionName);
    templ("load", _fromMemory ? "mload" : "calldataload");
    // Validation should use the type and not decodingType, because e.g.
    // the decoding type of an enum is a plain int.
    templ("validator", m_utils.validatorFunction(_type, true));
    return templ.render();
  });

}

std::string ABIFunctions::abiDecodingFunctionArray(ArrayType const& _type, bool _fromMemory)
{
  solAssert(_type.dataStoredIn(DataLocation::Memory), "");

  std::string functionName =
    "abi_decode_" +
    _type.identifier() +
    (_fromMemory ? "_fromMemory" : "");

  return createFunction(functionName, [&]() {
    std::string load = _fromMemory ? "mload" : "calldataload";
    Whiskers templ(
      R"(
        // <readableTypeName>
        function <functionName>(offset, end) -> array {
          if iszero(slt(add(offset, 0x1f), end)) { <revertString>() }
          let length := <retrieveLength>
          array := <abiDecodeAvailableLen>(<offset>, length, end)
        }
      )"
    );
    // TODO add test
    templ("revertString", revertReasonIfDebugFunction("ABI decoding: invalid calldata array offset"));
    templ("functionName", functionName);
    templ("readableTypeName", _type.toString(true));
    templ("retrieveLength", _type.isDynamicallySized() ? (load + "(offset)") : toCompactHexWithPrefix(_type.length()));
    templ("offset", _type.isDynamicallySized() ? "add(offset, 0x20)" : "offset");
    templ("abiDecodeAvailableLen", abiDecodingFunctionArrayAvailableLength(_type, _fromMemory));
    return templ.render();
  });
}

std::string ABIFunctions::abiDecodingFunctionArrayAvailableLength(ArrayType const& _type, bool _fromMemory)
{
  solAssert(_type.dataStoredIn(DataLocation::Memory), "");
  if (_type.isByteArrayOrString())
    return abiDecodingFunctionByteArrayAvailableLength(_type, _fromMemory);
  solAssert(_type.calldataStride() > 0, "");

  std::string functionName =
    "abi_decode_available_length_" +
    _type.identifier() +
    (_fromMemory ? "_fromMemory" : "");

  return createFunction(functionName, [&]() {
    Whiskers templ(R"(
      // <readableTypeName>
      function <functionName>(offset, length, end) -> array {
        array := <allocate>(<allocationSize>(length))
        let dst := array
        <?dynamic>
          mstore(array, length)
          dst := add(array, 0x20)
        </dynamic>
        let srcEnd := add(offset, mul(length, <stride>))
        if gt(srcEnd, end) {
          <revertInvalidStride>()
        }
        for { let src := offset } lt(src, srcEnd) { src := add(src, <stride>) }
        {
          <?dynamicBase>
            let innerOffset := <load>(src)
            if gt(innerOffset, 0xffffffffffffffff) { <revertStringOffset>() }
            let elementPos := add(offset, innerOffset)
          <!dynamicBase>
            let elementPos := src
          </dynamicBase>
          mstore(dst, <decodingFun>(elementPos, end))
          dst := add(dst, 0x20)
        }
      }
    )");
    templ("functionName", functionName);
    templ("readableTypeName", _type.toString(true));
    templ("allocate", m_utils.allocationFunction());
    templ("allocationSize", m_utils.arrayAllocationSizeFunction(_type));
    templ("stride", toCompactHexWithPrefix(_type.calldataStride()));
    templ("dynamic", _type.isDynamicallySized());
    templ("load", _fromMemory ? "mload" : "calldataload");
    templ("dynamicBase", _type.baseType()->isDynamicallyEncoded());
    templ(
      "revertInvalidStride",
      revertReasonIfDebugFunction("ABI decoding: invalid calldata array stride")
    );
    templ("revertStringOffset", revertReasonIfDebugFunction("ABI decoding: invalid calldata array offset"));
    templ("decodingFun", abiDecodingFunction(*_type.baseType(), _fromMemory, false));
    return templ.render();
  });
}

std::string ABIFunctions::abiDecodingFunctionCalldataArray(ArrayType const& _type)
{
  solAssert(_type.dataStoredIn(DataLocation::CallData), "");
  if (!_type.isDynamicallySized())
    solAssert(_type.length() < u256("0xffffffffffffffff"), "");
  solAssert(_type.calldataStride() > 0, "");
  solAssert(_type.calldataStride() < u256("0xffffffffffffffff"), "");

  std::string functionName =
    "abi_decode_" +
    _type.identifier();
  return createFunction(functionName, [&]() {
    Whiskers w;
    if (_type.isDynamicallySized())
    {
      w = Whiskers(R"(
        // <readableTypeName>
        function <functionName>(offset, end) -> arrayPos, length {
          if iszero(slt(add(offset, 0x1f), end)) { <revertStringOffset>() }
          length := calldataload(offset)
          if gt(length, 0xffffffffffffffff) { <revertStringLength>() }
          arrayPos := add(offset, 0x20)
          if gt(add(arrayPos, mul(length, <stride>)), end) { <revertStringPos>() }
        }
      )");
      w("revertStringOffset", revertReasonIfDebugFunction("ABI decoding: invalid calldata array offset"));
      w("revertStringLength", revertReasonIfDebugFunction("ABI decoding: invalid calldata array length"));
    }
    else
    {
      w = Whiskers(R"(
        // <readableTypeName>
        function <functionName>(offset, end) -> arrayPos {
          arrayPos := offset
          if gt(add(arrayPos, mul(<length>, <stride>)), end) { <revertStringPos>() }
        }
      )");
      w("length", toCompactHexWithPrefix(_type.length()));
    }
    w("revertStringPos", revertReasonIfDebugFunction("ABI decoding: invalid calldata array stride"));
    w("functionName", functionName);
    w("readableTypeName", _type.toString(true));
    w("stride", toCompactHexWithPrefix(_type.calldataStride()));

    // TODO add test
    return w.render();
  });
}

std::string ABIFunctions::abiDecodingFunctionByteArrayAvailableLength(ArrayType const& _type, bool _fromMemory)
{
  solAssert(_type.dataStoredIn(DataLocation::Memory), "");
  solAssert(_type.isByteArrayOrString(), "");

  std::string functionName =
    "abi_decode_available_length_" +
    _type.identifier() +
    (_fromMemory ? "_fromMemory" : "");

  return createFunction(functionName, [&]() {
    Whiskers templ(R"(
      function <functionName>(src, length, end) -> array {
        array := <allocate>(<allocationSize>(length))
        mstore(array, length)
        let dst := add(array, 0x20)
        if gt(add(src, length), end) { <revertStringLength>() }
        <copyToMemFun>(src, dst, length)
      }
    )");
    templ("revertStringLength", revertReasonIfDebugFunction("ABI decoding: invalid byte array length"));
    templ("functionName", functionName);
    templ("allocate", m_utils.allocationFunction());
    templ("allocationSize", m_utils.arrayAllocationSizeFunction(_type));
    templ("copyToMemFun", m_utils.copyToMemoryFunction(!_fromMemory, /*cleanup*/true));
    return templ.render();
  });
}

std::string ABIFunctions::abiDecodingFunctionCalldataStruct(StructType const& _type)
{
  solAssert(_type.dataStoredIn(DataLocation::CallData), "");
  std::string functionName =
    "abi_decode_" +
    _type.identifier();

  return createFunction(functionName, [&]() {
    Whiskers w{R"(
        // <readableTypeName>
        function <functionName>(offset, end) -> value {
          if slt(sub(end, offset), <minimumSize>) { <revertString>() }
          value := offset
        }
    )"};
    // TODO add test
    w("revertString", revertReasonIfDebugFunction("ABI decoding: struct calldata too short"));
    w("functionName", functionName);
    w("readableTypeName", _type.toString(true));
    w("minimumSize", std::to_string(_type.isDynamicallyEncoded() ? _type.calldataEncodedTailSize() : _type.calldataEncodedSize(true)));
    return w.render();
  });
}

std::string ABIFunctions::abiDecodingFunctionStruct(StructType const& _type, bool _fromMemory)
{
  solAssert(!_type.dataStoredIn(DataLocation::CallData), "");
  std::string functionName =
    "abi_decode_" +
    _type.identifier() +
    (_fromMemory ? "_fromMemory" : "");

  return createFunction(functionName, [&]() {
    Whiskers templ(R"(
      // <readableTypeName>
      function <functionName>(headStart, end) -> value {
        if slt(sub(end, headStart), <minimumSize>) { <revertString>() }
        value := <allocate>(<memorySize>)
        <#members>
        {
          // <memberName>
          <decode>
        }
        </members>
      }
    )");
    // TODO add test
    templ("revertString", revertReasonIfDebugFunction("ABI decoding: struct data too short"));
    templ("functionName", functionName);
    templ("readableTypeName", _type.toString(true));
    templ("allocate", m_utils.allocationFunction());
    solAssert(_type.memoryDataSize() < u256("0xffffffffffffffff"), "");
    templ("memorySize", toCompactHexWithPrefix(_type.memoryDataSize()));
    size_t headPos = 0;
    std::vector<std::map<std::string, std::string>> members;
    for (auto const& member: _type.members(nullptr))
    {
      solAssert(member.type, "");
      solAssert(!member.type->containsNestedMapping(), "");
      auto decodingType = member.type->decodingType();
      solAssert(decodingType, "");
      Whiskers memberTempl(R"(
        <?dynamic>
          let offset := <load>(add(headStart, <pos>))
          if gt(offset, 0xffffffffffffffff) { <revertString>() }
        <!dynamic>
          let offset := <pos>
        </dynamic>
        mstore(add(value, <memoryOffset>), <abiDecode>(add(headStart, offset), end))
      )");
      memberTempl("dynamic", decodingType->isDynamicallyEncoded());
      // TODO add test
      memberTempl("revertString", revertReasonIfDebugFunction("ABI decoding: invalid struct offset"));
      memberTempl("load", _fromMemory ? "mload" : "calldataload");
      memberTempl("pos", std::to_string(headPos));
      memberTempl("memoryOffset", toCompactHexWithPrefix(_type.memoryOffsetOfMember(member.name)));
      memberTempl("abiDecode", abiDecodingFunction(*member.type, _fromMemory, false));

      members.emplace_back();
      members.back()["decode"] = memberTempl.render();
      members.back()["memberName"] = member.name;
      headPos += decodingType->calldataHeadSize();
    }
    templ("members", members);
    templ("minimumSize", toCompactHexWithPrefix(headPos));
    return templ.render();
  });
}

std::string ABIFunctions::abiDecodingFunctionFunctionType(FunctionType const& _type, bool _fromMemory, bool _forUseOnStack)
{
  solAssert(_type.kind() == FunctionType::Kind::External, "");

  std::string functionName =
    "abi_decode_" +
    _type.identifier() +
    (_fromMemory ? "_fromMemory" : "") +
    (_forUseOnStack ? "_onStack" : "");

  return createFunction(functionName, [&]() {
    if (_forUseOnStack)
    {
      return Whiskers(R"(
        function <functionName>(offset, end) -> addr, function_selector {
          addr, function_selector := <splitExtFun>(<decodeFun>(offset, end))
        }
      )")
      ("functionName", functionName)
      ("decodeFun", abiDecodingFunctionFunctionType(_type, _fromMemory, false))
      ("splitExtFun", m_utils.splitExternalFunctionIdFunction())
      .render();
    }
    else
    {
      return Whiskers(R"(
        function <functionName>(offset, end) -> fun {
          fun := <load>(offset)
          <validateExtFun>(fun)
        }
      )")
      ("functionName", functionName)
      ("load", _fromMemory ? "mload" : "calldataload")
      ("validateExtFun", m_utils.validatorFunction(_type, true))
      .render();
    }
  });
}

std::string ABIFunctions::calldataAccessFunction(Type const& _type)
{
  solAssert(_type.isValueType() || _type.dataStoredIn(DataLocation::CallData), "");
  std::string functionName = "calldata_access_" + _type.identifier();
  return createFunction(functionName, [&]() {
    if (_type.isDynamicallyEncoded())
    {
      unsigned int tailSize = _type.calldataEncodedTailSize();
      solAssert(tailSize > 1, "");
      Whiskers w(R"(
        function <functionName>(base_ref, ptr) -> <return> {
          let rel_offset_of_tail := calldataload(ptr)
          if iszero(slt(rel_offset_of_tail, sub(sub(calldatasize(), base_ref), sub(<neededLength>, 1)))) { <revertStringOffset>() }
          value := add(rel_offset_of_tail, base_ref)
          <handleLength>
        }
      )");
      if (_type.isDynamicallySized())
      {
        auto const* arrayType = dynamic_cast<ArrayType const*>(&_type);
        solAssert(!!arrayType, "");
        w("handleLength", Whiskers(R"(
          length := calldataload(value)
          value := add(value, 0x20)
          if gt(length, 0xffffffffffffffff) { <revertStringLength>() }
          if sgt(value, sub(calldatasize(), mul(length, <calldataStride>))) { <revertStringStride>() }
        )")
        ("calldataStride", toCompactHexWithPrefix(arrayType->calldataStride()))
        // TODO add test
        ("revertStringLength", revertReasonIfDebugFunction("Invalid calldata access length"))
        // TODO add test
        ("revertStringStride", revertReasonIfDebugFunction("Invalid calldata access stride"))
        .render());
        w("return", "value, length");
      }
      else
      {
        w("handleLength", "");
        w("return", "value");
      }
      w("neededLength", toCompactHexWithPrefix(tailSize));
      w("functionName", functionName);
      w("revertStringOffset", revertReasonIfDebugFunction("Invalid calldata access offset"));
      return w.render();
    }
    else if (_type.isValueType())
    {
      std::string decodingFunction;
      if (auto const* functionType = dynamic_cast<FunctionType const*>(&_type))
        decodingFunction = abiDecodingFunctionFunctionType(*functionType, false, false);
      else
        decodingFunction = abiDecodingFunctionValueType(_type, false);
      // Note that the second argument to the decoding function should be discarded after inlining.
      return Whiskers(R"(
        function <functionName>(baseRef, ptr) -> value {
          value := <decodingFunction>(ptr, add(ptr, 32))
        }
      )")
      ("functionName", functionName)
      ("decodingFunction", decodingFunction)
      .render();
    }
    else
    {
      solAssert(
        _type.category() == Type::Category::Array ||
        _type.category() == Type::Category::Struct,
        ""
      );
      return Whiskers(R"(
        function <functionName>(baseRef, ptr) -> value {
          value := ptr
        }
      )")
      ("functionName", functionName)
      .render();
    }
  });
}

std::string ABIFunctions::arrayStoreLengthForEncodingFunction(ArrayType const& _type, EncodingOptions const& _options)
{
  std::string functionName = "array_storeLengthForEncoding_" + _type.identifier() + _options.toFunctionNameSuffix();
  return createFunction(functionName, [&]() {
    if (_type.isDynamicallySized() && !_options.dynamicInplace)
      return Whiskers(R"(
        function <functionName>(pos, length) -> updated_pos {
          mstore(pos, length)
          updated_pos := add(pos, 0x20)
        }
      )")
      ("functionName", functionName)
      .render();
    else
      return Whiskers(R"(
        function <functionName>(pos, length) -> updated_pos {
          updated_pos := pos
        }
      )")
      ("functionName", functionName)
      .render();
  });
}

std::string ABIFunctions::createFunction(std::string const& _name, std::function<std::string ()> const& _creator)
{
  return m_functionCollector.createFunction(_name, _creator);
}

size_t ABIFunctions::headSize(TypePointers const& _targetTypes)
{
  size_t headSize = 0;
  for (auto const& t: _targetTypes)
    headSize += t->calldataHeadSize();

  return headSize;
}

size_t ABIFunctions::numVariablesForType(Type const& _type, EncodingOptions const& _options)
{
  if (_type.category() == Type::Category::Function && !_options.encodeFunctionFromStack)
    return 1;
  else
    return _type.sizeOnStack();
}

std::string ABIFunctions::revertReasonIfDebugFunction(std::string const& _message)
{
  return m_utils.revertReasonIfDebugFunction(_message);
}

Coverage Report

Created: 2025-09-08 08:10