/*

  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 <c@ethdev.com>

 * @date 2014

 * Solidity AST to EVM bytecode compiler for expressions.

 */

#include <libsolidity/codegen/ExpressionCompiler.h>

#include <libsolidity/codegen/ReturnInfo.h>

#include <libsolidity/codegen/CompilerContext.h>

#include <libsolidity/codegen/CompilerUtils.h>

#include <libsolidity/codegen/LValue.h>

#include <libsolidity/ast/AST.h>

#include <libsolidity/ast/ASTUtils.h>

#include <libsolidity/ast/TypeProvider.h>

#include <libevmasm/GasMeter.h>

#include <libsolutil/Common.h>

#include <libsolutil/FunctionSelector.h>

#include <libsolutil/Keccak256.h>

#include <libsolutil/Whiskers.h>

#include <libsolutil/StackTooDeepString.h>

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

#include <numeric>

#include <utility>

using namespace std;

using namespace solidity;

using namespace solidity::evmasm;

using namespace solidity::frontend;

using namespace solidity::langutil;

using namespace solidity::util;

namespace

{

Type const* closestType(Type const* _type, Type const* _targetType, bool _isShiftOp)

{

  if (_isShiftOp)

    return _type->mobileType();

  else if (auto const* tupleType = dynamic_cast<TupleType const*>(_type))

  {

    solAssert(_targetType, "");

    TypePointers const& targetComponents = dynamic_cast<TupleType const&>(*_targetType).components();

    solAssert(tupleType->components().size() == targetComponents.size(), "");

    TypePointers tempComponents(targetComponents.size());

    for (size_t i = 0; i < targetComponents.size(); ++i)

    {

      if (tupleType->components()[i] && targetComponents[i])

      {

        tempComponents[i] = closestType(tupleType->components()[i], targetComponents[i], _isShiftOp);

        solAssert(tempComponents[i], "");

      }

    }

    return TypeProvider::tuple(move(tempComponents));

  }

  else

    return _targetType->dataStoredIn(DataLocation::Storage) ? _type->mobileType() : _targetType;

}

}

void ExpressionCompiler::compile(Expression const& _expression)

{

  _expression.accept(*this);

}

void ExpressionCompiler::appendStateVariableInitialization(VariableDeclaration const& _varDecl)

{

  if (!_varDecl.value())

    return;

  Type const* type = _varDecl.value()->annotation().type;

  solAssert(!!type, "Type information not available.");

  CompilerContext::LocationSetter locationSetter(m_context, _varDecl);

  _varDecl.value()->accept(*this);

  if (_varDecl.annotation().type->dataStoredIn(DataLocation::Storage))

  {

    // reference type, only convert value to mobile type and do final conversion in storeValue.

    auto mt = type->mobileType();

    solAssert(mt, "");

    utils().convertType(*type, *mt);

    type = mt;

  }

  else

  {

    utils().convertType(*type, *_varDecl.annotation().type);

    type = _varDecl.annotation().type;

  }

  if (_varDecl.immutable())

    ImmutableItem(m_context, _varDecl).storeValue(*type, _varDecl.location(), true);

  else

    StorageItem(m_context, _varDecl).storeValue(*type, _varDecl.location(), true);

}

void ExpressionCompiler::appendConstStateVariableAccessor(VariableDeclaration const& _varDecl)

{

  solAssert(_varDecl.isConstant(), "");

  acceptAndConvert(*_varDecl.value(), *_varDecl.annotation().type);

  // append return

  m_context << dupInstruction(_varDecl.annotation().type->sizeOnStack() + 1);

  m_context.appendJump(evmasm::AssemblyItem::JumpType::OutOfFunction);

}

void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)

{

  solAssert(!_varDecl.isConstant(), "");

  CompilerContext::LocationSetter locationSetter(m_context, _varDecl);

  FunctionType accessorType(_varDecl);

  TypePointers paramTypes = accessorType.parameterTypes();

  if (_varDecl.immutable())

    solAssert(paramTypes.empty(), "");

  m_context.adjustStackOffset(static_cast<int>(1 + CompilerUtils::sizeOnStack(paramTypes)));

  if (!_varDecl.immutable())

  {

    // retrieve the position of the variable

    auto const& location = m_context.storageLocationOfVariable(_varDecl);

    m_context << location.first << u256(location.second);

  }

  Type const* returnType = _varDecl.annotation().type;

  for (size_t i = 0; i < paramTypes.size(); ++i)

  {

    if (auto mappingType = dynamic_cast<MappingType const*>(returnType))

    {

      solAssert(CompilerUtils::freeMemoryPointer >= 0x40, "");

      // pop offset

      m_context << Instruction::POP;

      if (paramTypes[i]->isDynamicallySized())

      {

        solAssert(

          dynamic_cast<ArrayType const&>(*paramTypes[i]).isByteArrayOrString(),

          "Expected string or byte array for mapping key type"

        );

        // stack: <keys..> <slot position>

        // copy key[i] to top.

        utils().copyToStackTop(static_cast<unsigned>(paramTypes.size() - i + 1), 1);

        m_context.appendInlineAssembly(R"({

          let key_len := mload(key_ptr)

          // Temp. use the memory after the array data for the slot

          // position

          let post_data_ptr := add(key_ptr, add(key_len, 0x20))

          let orig_data := mload(post_data_ptr)

          mstore(post_data_ptr, slot_pos)

          let hash := keccak256(add(key_ptr, 0x20), add(key_len, 0x20))

          mstore(post_data_ptr, orig_data)

          slot_pos := hash

        })", {"slot_pos", "key_ptr"});

        m_context << Instruction::POP;

      }

      else

      {

        solAssert(paramTypes[i]->isValueType(), "Expected value type for mapping key");

        // move storage offset to memory.

        utils().storeInMemory(32);

        // move key to memory.

        utils().copyToStackTop(static_cast<unsigned>(paramTypes.size() - i), 1);

        utils().storeInMemory(0);

        m_context << u256(64) << u256(0);

        m_context << Instruction::KECCAK256;

      }

      // push offset

      m_context << u256(0);

      returnType = mappingType->valueType();

    }

    else if (auto arrayType = dynamic_cast<ArrayType const*>(returnType))

    {

      // pop offset

      m_context << Instruction::POP;

      utils().copyToStackTop(static_cast<unsigned>(paramTypes.size() - i + 1), 1);

      ArrayUtils(m_context).retrieveLength(*arrayType, 1);

      // Stack: ref [length] index length

      // check out-of-bounds access

      m_context << Instruction::DUP2 << Instruction::LT;

      auto tag = m_context.appendConditionalJump();

      m_context << u256(0) << Instruction::DUP1 << Instruction::REVERT;

      m_context << tag;

      ArrayUtils(m_context).accessIndex(*arrayType, false);

      returnType = arrayType->baseType();

    }

    else

      solAssert(false, "Index access is allowed only for \"mapping\" and \"array\" types.");

  }

  // remove index arguments.

  if (paramTypes.size() == 1)

    m_context << Instruction::SWAP2 << Instruction::POP << Instruction::SWAP1;

  else if (paramTypes.size() >= 2)

  {

    m_context << swapInstruction(static_cast<unsigned>(paramTypes.size()));

    m_context << Instruction::POP;

    m_context << swapInstruction(static_cast<unsigned>(paramTypes.size()));

    utils().popStackSlots(paramTypes.size() - 1);

  }

  unsigned retSizeOnStack = 0;

  auto returnTypes = accessorType.returnParameterTypes();

  solAssert(returnTypes.size() >= 1, "");

  if (StructType const* structType = dynamic_cast<StructType const*>(returnType))

  {

    solAssert(!_varDecl.immutable(), "");

    // remove offset

    m_context << Instruction::POP;

    auto const& names = accessorType.returnParameterNames();

    // struct

    for (size_t i = 0; i < names.size(); ++i)

    {

      if (returnTypes[i]->category() == Type::Category::Mapping)

        continue;

      if (auto arrayType = dynamic_cast<ArrayType const*>(returnTypes[i]))

        if (!arrayType->isByteArrayOrString())

          continue;

      pair<u256, unsigned> const& offsets = structType->storageOffsetsOfMember(names[i]);

      m_context << Instruction::DUP1 << u256(offsets.first) << Instruction::ADD << u256(offsets.second);

      Type const* memberType = structType->memberType(names[i]);

      StorageItem(m_context, *memberType).retrieveValue(SourceLocation(), true);

      utils().convertType(*memberType, *returnTypes[i]);

      utils().moveToStackTop(returnTypes[i]->sizeOnStack());

      retSizeOnStack += returnTypes[i]->sizeOnStack();

    }

    // remove slot

    m_context << Instruction::POP;

  }

  else

  {

    // simple value or array

    solAssert(returnTypes.size() == 1, "");

    if (_varDecl.immutable())

      ImmutableItem(m_context, _varDecl).retrieveValue(SourceLocation());

    else

      StorageItem(m_context, *returnType).retrieveValue(SourceLocation(), true);

    utils().convertType(*returnType, *returnTypes.front());

    retSizeOnStack = returnTypes.front()->sizeOnStack();

  }

  solAssert(retSizeOnStack == utils().sizeOnStack(returnTypes), "");

  if (retSizeOnStack > 15)

    BOOST_THROW_EXCEPTION(

      StackTooDeepError() <<

      errinfo_sourceLocation(_varDecl.location()) <<

      util::errinfo_comment(util::stackTooDeepString)

    );

  m_context << dupInstruction(retSizeOnStack + 1);

  m_context.appendJump(evmasm::AssemblyItem::JumpType::OutOfFunction);

}

bool ExpressionCompiler::visit(Conditional const& _condition)

{

  CompilerContext::LocationSetter locationSetter(m_context, _condition);

  _condition.condition().accept(*this);

  evmasm::AssemblyItem trueTag = m_context.appendConditionalJump();

  acceptAndConvert(_condition.falseExpression(), *_condition.annotation().type);

  evmasm::AssemblyItem endTag = m_context.appendJumpToNew();

  m_context << trueTag;

  int offset = static_cast<int>(_condition.annotation().type->sizeOnStack());

  m_context.adjustStackOffset(-offset);

  acceptAndConvert(_condition.trueExpression(), *_condition.annotation().type);

  m_context << endTag;

  return false;

}

bool ExpressionCompiler::visit(Assignment const& _assignment)

{

  CompilerContext::LocationSetter locationSetter(m_context, _assignment);

  Token op = _assignment.assignmentOperator();

  Token binOp = op == Token::Assign ? op : TokenTraits::AssignmentToBinaryOp(op);

  Type const& leftType = *_assignment.leftHandSide().annotation().type;

  if (leftType.category() == Type::Category::Tuple)

  {

    solAssert(*_assignment.annotation().type == TupleType(), "");

    solAssert(op == Token::Assign, "");

  }

  else

    solAssert(*_assignment.annotation().type == leftType, "");

  bool cleanupNeeded = false;

  if (op != Token::Assign)

    cleanupNeeded = cleanupNeededForOp(leftType.category(), binOp, m_context.arithmetic());

  _assignment.rightHandSide().accept(*this);

  // Perform some conversion already. This will convert storage types to memory and literals

  // to their actual type, but will not convert e.g. memory to storage.

  Type const* rightIntermediateType = closestType(

    _assignment.rightHandSide().annotation().type,

    _assignment.leftHandSide().annotation().type,

    op != Token::Assign && TokenTraits::isShiftOp(binOp)

  );

  solAssert(rightIntermediateType, "");

  utils().convertType(*_assignment.rightHandSide().annotation().type, *rightIntermediateType, cleanupNeeded);

  _assignment.leftHandSide().accept(*this);

  solAssert(!!m_currentLValue, "LValue not retrieved.");

  if (op == Token::Assign)

    m_currentLValue->storeValue(*rightIntermediateType, _assignment.location());

  else  // compound assignment

  {

    solAssert(binOp != Token::Exp, "Compound exp is not possible.");

    solAssert(leftType.isValueType(), "Compound operators only available for value types.");

    unsigned lvalueSize = m_currentLValue->sizeOnStack();

    unsigned itemSize = _assignment.annotation().type->sizeOnStack();

    if (lvalueSize > 0)

    {

      utils().copyToStackTop(lvalueSize + itemSize, itemSize);

      utils().copyToStackTop(itemSize + lvalueSize, lvalueSize);

      // value lvalue_ref value lvalue_ref

    }

    m_currentLValue->retrieveValue(_assignment.location(), true);

    utils().convertType(leftType, leftType, cleanupNeeded);

    if (TokenTraits::isShiftOp(binOp))

      appendShiftOperatorCode(binOp, leftType, *rightIntermediateType);

    else

    {

      solAssert(leftType == *rightIntermediateType, "");

      appendOrdinaryBinaryOperatorCode(binOp, leftType);

    }

    if (lvalueSize > 0)

    {

      if (itemSize + lvalueSize > 16)

        BOOST_THROW_EXCEPTION(

          StackTooDeepError() <<

          errinfo_sourceLocation(_assignment.location()) <<

          util::errinfo_comment(util::stackTooDeepString)

        );

      // value [lvalue_ref] updated_value

      for (unsigned i = 0; i < itemSize; ++i)

        m_context << swapInstruction(itemSize + lvalueSize) << Instruction::POP;

    }

    m_currentLValue->storeValue(*_assignment.annotation().type, _assignment.location());

  }

  m_currentLValue.reset();

  return false;

}

bool ExpressionCompiler::visit(TupleExpression const& _tuple)

{

  if (_tuple.isInlineArray())

  {

    ArrayType const& arrayType = dynamic_cast<ArrayType const&>(*_tuple.annotation().type);

    solAssert(!arrayType.isDynamicallySized(), "Cannot create dynamically sized inline array.");

    utils().allocateMemory(max(u256(32u), arrayType.memoryDataSize()));

    m_context << Instruction::DUP1;

    for (auto const& component: _tuple.components())

    {

      acceptAndConvert(*component, *arrayType.baseType(), true);

      utils().storeInMemoryDynamic(*arrayType.baseType(), true);

    }

    m_context << Instruction::POP;

  }

  else

  {

    vector<unique_ptr<LValue>> lvalues;

    for (auto const& component: _tuple.components())

      if (component)

      {

        component->accept(*this);

        if (_tuple.annotation().willBeWrittenTo)

        {

          solAssert(!!m_currentLValue, "");

          lvalues.push_back(move(m_currentLValue));

        }

      }

      else if (_tuple.annotation().willBeWrittenTo)

        lvalues.push_back(unique_ptr<LValue>());

    if (_tuple.annotation().willBeWrittenTo)

    {

      if (_tuple.components().size() == 1)

        m_currentLValue = move(lvalues[0]);

      else

        m_currentLValue = make_unique<TupleObject>(m_context, move(lvalues));

    }

  }

  return false;

}

bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)

{

  CompilerContext::LocationSetter locationSetter(m_context, _unaryOperation);

  Type const& type = *_unaryOperation.annotation().type;

  if (type.category() == Type::Category::RationalNumber)

  {

    m_context << type.literalValue(nullptr);

    return false;

  }

  _unaryOperation.subExpression().accept(*this);

  switch (_unaryOperation.getOperator())

  {

  case Token::Not: // !

    m_context << Instruction::ISZERO;

    break;

  case Token::BitNot: // ~

    m_context << Instruction::NOT;

    break;

  case Token::Delete: // delete

    solAssert(!!m_currentLValue, "LValue not retrieved.");

    m_currentLValue->setToZero(_unaryOperation.location());

    m_currentLValue.reset();

    break;

  case Token::Inc: // ++ (pre- or postfix)

  case Token::Dec: // -- (pre- or postfix)

    solAssert(!!m_currentLValue, "LValue not retrieved.");

    solUnimplementedAssert(

      type.category() != Type::Category::FixedPoint,

      "Not yet implemented - FixedPointType."

    );

    m_currentLValue->retrieveValue(_unaryOperation.location());

    if (!_unaryOperation.isPrefixOperation())

    {

      // store value for later

      solUnimplementedAssert(type.sizeOnStack() == 1, "Stack size != 1 not implemented.");

      m_context << Instruction::DUP1;

      if (m_currentLValue->sizeOnStack() > 0)

        for (unsigned i = 1 + m_currentLValue->sizeOnStack(); i > 0; --i)

          m_context << swapInstruction(i);

    }

    if (_unaryOperation.getOperator() == Token::Inc)

    {

      if (m_context.arithmetic() == Arithmetic::Checked)

        m_context.callYulFunction(m_context.utilFunctions().incrementCheckedFunction(type), 1, 1);

      else

      {

        m_context << u256(1);

        m_context << Instruction::ADD;

      }

    }

    else

    {

      if (m_context.arithmetic() == Arithmetic::Checked)

        m_context.callYulFunction(m_context.utilFunctions().decrementCheckedFunction(type), 1, 1);

      else

      {

        m_context << u256(1);

        m_context << Instruction::SWAP1 << Instruction::SUB;

      }

    }

    // Stack for prefix: [ref...] (*ref)+-1

    // Stack for postfix: *ref [ref...] (*ref)+-1

    for (unsigned i = m_currentLValue->sizeOnStack(); i > 0; --i)

      m_context << swapInstruction(i);

    m_currentLValue->storeValue(

      *_unaryOperation.annotation().type, _unaryOperation.location(),

      !_unaryOperation.isPrefixOperation());

    m_currentLValue.reset();

    break;

  case Token::Add: // +

    // unary add, so basically no-op

    break;

  case Token::Sub: // -

    solUnimplementedAssert(

      type.category() != Type::Category::FixedPoint,

      "Not yet implemented - FixedPointType."

    );

    if (m_context.arithmetic() == Arithmetic::Checked)

      m_context.callYulFunction(m_context.utilFunctions().negateNumberCheckedFunction(type), 1, 1);

    else

      m_context << u256(0) << Instruction::SUB;

    break;

  default:

    solAssert(false, "Invalid unary operator: " + string(TokenTraits::toString(_unaryOperation.getOperator())));

  }

  return false;

}

bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)

{

  CompilerContext::LocationSetter locationSetter(m_context, _binaryOperation);

  Expression const& leftExpression = _binaryOperation.leftExpression();

  Expression const& rightExpression = _binaryOperation.rightExpression();

  solAssert(!!_binaryOperation.annotation().commonType, "");

  Type const* commonType = _binaryOperation.annotation().commonType;

  Token const c_op = _binaryOperation.getOperator();

  if (c_op == Token::And || c_op == Token::Or) // special case: short-circuiting

    appendAndOrOperatorCode(_binaryOperation);

  else if (commonType->category() == Type::Category::RationalNumber)

    m_context << commonType->literalValue(nullptr);

  else

  {

    bool cleanupNeeded = cleanupNeededForOp(commonType->category(), c_op, m_context.arithmetic());

    Type const* leftTargetType = commonType;

    Type const* rightTargetType =

      TokenTraits::isShiftOp(c_op) || c_op == Token::Exp ?

      rightExpression.annotation().type->mobileType() :

      commonType;

    solAssert(rightTargetType, "");

    // for commutative operators, push the literal as late as possible to allow improved optimization

    auto isLiteral = [](Expression const& _e)

    {

      return dynamic_cast<Literal const*>(&_e) || _e.annotation().type->category() == Type::Category::RationalNumber;

    };

    bool swap = m_optimiseOrderLiterals && TokenTraits::isCommutativeOp(c_op) && isLiteral(rightExpression) && !isLiteral(leftExpression);

    if (swap)

    {

      acceptAndConvert(leftExpression, *leftTargetType, cleanupNeeded);

      acceptAndConvert(rightExpression, *rightTargetType, cleanupNeeded);

    }

    else

    {

      acceptAndConvert(rightExpression, *rightTargetType, cleanupNeeded);

      acceptAndConvert(leftExpression, *leftTargetType, cleanupNeeded);

    }

    if (TokenTraits::isShiftOp(c_op))

      // shift only cares about the signedness of both sides

      appendShiftOperatorCode(c_op, *leftTargetType, *rightTargetType);

    else if (c_op == Token::Exp)

      appendExpOperatorCode(*leftTargetType, *rightTargetType);

    else if (TokenTraits::isCompareOp(c_op))

      appendCompareOperatorCode(c_op, *commonType);

    else

      appendOrdinaryBinaryOperatorCode(c_op, *commonType);

  }

  // do not visit the child nodes, we already did that explicitly

  return false;

}

bool ExpressionCompiler::visit(FunctionCall const& _functionCall)

{

  auto functionCallKind = *_functionCall.annotation().kind;

  CompilerContext::LocationSetter locationSetter(m_context, _functionCall);

  if (functionCallKind == FunctionCallKind::TypeConversion)

  {

    solAssert(_functionCall.arguments().size() == 1, "");

    solAssert(_functionCall.names().empty(), "");

    auto const& expression = *_functionCall.arguments().front();

    auto const& targetType = *_functionCall.annotation().type;

    if (auto const* typeType = dynamic_cast<TypeType const*>(expression.annotation().type))

      if (auto const* addressType = dynamic_cast<AddressType const*>(&targetType))

      {

        auto const* contractType = dynamic_cast<ContractType const*>(typeType->actualType());

        solAssert(

          contractType &&

          contractType->contractDefinition().isLibrary() &&

          addressType->stateMutability() == StateMutability::NonPayable,

          ""

        );

        m_context.appendLibraryAddress(contractType->contractDefinition().fullyQualifiedName());

        return false;

      }

    acceptAndConvert(expression, targetType);

    return false;

  }

  FunctionTypePointer functionType;

  if (functionCallKind == FunctionCallKind::StructConstructorCall)

  {

    auto const& type = dynamic_cast<TypeType const&>(*_functionCall.expression().annotation().type);

    auto const& structType = dynamic_cast<StructType const&>(*type.actualType());

    functionType = structType.constructorType();

  }

  else

    functionType = dynamic_cast<FunctionType const*>(_functionCall.expression().annotation().type);

  TypePointers parameterTypes = functionType->parameterTypes();

  vector<ASTPointer<Expression const>> const& arguments = _functionCall.sortedArguments();

  if (functionCallKind == FunctionCallKind::StructConstructorCall)

  {

    TypeType const& type = dynamic_cast<TypeType const&>(*_functionCall.expression().annotation().type);

    auto const& structType = dynamic_cast<StructType const&>(*type.actualType());

    utils().allocateMemory(max(u256(32u), structType.memoryDataSize()));

    m_context << Instruction::DUP1;

    for (unsigned i = 0; i < arguments.size(); ++i)

    {

      acceptAndConvert(*arguments[i], *functionType->parameterTypes()[i]);

      utils().storeInMemoryDynamic(*functionType->parameterTypes()[i]);

    }

    m_context << Instruction::POP;

  }

  else

  {

    FunctionType const& function = *functionType;

    if (function.bound())

      solAssert(

        function.kind() == FunctionType::Kind::DelegateCall ||

        function.kind() == FunctionType::Kind::Internal ||

        function.kind() == FunctionType::Kind::ArrayPush ||

        function.kind() == FunctionType::Kind::ArrayPop,

      "");

    switch (function.kind())

    {

    case FunctionType::Kind::Declaration:

      solAssert(false, "Attempted to generate code for calling a function definition.");

      break;

    case FunctionType::Kind::Internal:

    {

      // Calling convention: Caller pushes return address and arguments

      // Callee removes them and pushes return values

      evmasm::AssemblyItem returnLabel = m_context.pushNewTag();

      for (unsigned i = 0; i < arguments.size(); ++i)

        acceptAndConvert(*arguments[i], *function.parameterTypes()[i]);

      {

        bool shortcutTaken = false;

        if (auto identifier = dynamic_cast<Identifier const*>(&_functionCall.expression()))

        {

          solAssert(!function.bound(), "");

          if (auto functionDef = dynamic_cast<FunctionDefinition const*>(identifier->annotation().referencedDeclaration))

          {

            // Do not directly visit the identifier, because this way, we can avoid

            // the runtime entry label to be created at the creation time context.

            CompilerContext::LocationSetter locationSetter2(m_context, *identifier);

            solAssert(*identifier->annotation().requiredLookup == VirtualLookup::Virtual, "");

            utils().pushCombinedFunctionEntryLabel(

              functionDef->resolveVirtual(m_context.mostDerivedContract()),

              false

            );

            shortcutTaken = true;

          }

        }

        if (!shortcutTaken)

          _functionCall.expression().accept(*this);

      }

      unsigned parameterSize = CompilerUtils::sizeOnStack(function.parameterTypes());

      if (function.bound())

      {

        // stack: arg2, ..., argn, label, arg1

        unsigned depth = parameterSize + 1;

        utils().moveIntoStack(depth, function.selfType()->sizeOnStack());

        parameterSize += function.selfType()->sizeOnStack();

      }

      if (m_context.runtimeContext())

        // We have a runtime context, so we need the creation part.

        utils().rightShiftNumberOnStack(32);

      else

        // Extract the runtime part.

        m_context << ((u256(1) << 32) - 1) << Instruction::AND;

      m_context.appendJump(evmasm::AssemblyItem::JumpType::IntoFunction);

      m_context << returnLabel;

      unsigned returnParametersSize = CompilerUtils::sizeOnStack(function.returnParameterTypes());

      // callee adds return parameters, but removes arguments and return label

      m_context.adjustStackOffset(static_cast<int>(returnParametersSize - parameterSize) - 1);

      break;

    }

    case FunctionType::Kind::BareCall:

    case FunctionType::Kind::BareDelegateCall:

    case FunctionType::Kind::BareStaticCall:

      solAssert(!_functionCall.annotation().tryCall, "");

      [[fallthrough]];

    case FunctionType::Kind::External:

    case FunctionType::Kind::DelegateCall:

      _functionCall.expression().accept(*this);

      appendExternalFunctionCall(function, arguments, _functionCall.annotation().tryCall);

      break;

    case FunctionType::Kind::BareCallCode:

      solAssert(false, "Callcode has been removed.");

    case FunctionType::Kind::Creation:

    {

      _functionCall.expression().accept(*this);

      // Stack: [salt], [value]

      solAssert(!function.gasSet(), "Gas limit set for contract creation.");

      solAssert(function.returnParameterTypes().size() == 1, "");

      TypePointers argumentTypes;

      for (auto const& arg: arguments)

      {

        arg->accept(*this);

        argumentTypes.push_back(arg->annotation().type);

      }

      ContractDefinition const* contract =

        &dynamic_cast<ContractType const&>(*function.returnParameterTypes().front()).contractDefinition();

      utils().fetchFreeMemoryPointer();

      utils().copyContractCodeToMemory(*contract, true);

      utils().abiEncode(argumentTypes, function.parameterTypes());

      // now on stack: [salt], [value], memory_end_ptr

      // need: [salt], size, offset, value

      if (function.saltSet())

      {

        m_context << dupInstruction(2 + (function.valueSet() ? 1 : 0));

        m_context << Instruction::SWAP1;

      }

      // now: [salt], [value], [salt], memory_end_ptr

      utils().toSizeAfterFreeMemoryPointer();

      // now: [salt], [value], [salt], size, offset

      if (function.valueSet())

        m_context << dupInstruction(3 + (function.saltSet() ? 1 : 0));

      else

        m_context << u256(0);

      // now: [salt], [value], [salt], size, offset, value

      if (function.saltSet())

        m_context << Instruction::CREATE2;

      else

        m_context << Instruction::CREATE;

      // now: [salt], [value], address

      if (function.valueSet())

        m_context << swapInstruction(1) << Instruction::POP;

      if (function.saltSet())

        m_context << swapInstruction(1) << Instruction::POP;

      // Check if zero (reverted)

      m_context << Instruction::DUP1 << Instruction::ISZERO;

      if (_functionCall.annotation().tryCall)

      {

        // If this is a try call, return "<address> 1" in the success case and

        // "0" in the error case.

        AssemblyItem errorCase = m_context.appendConditionalJump();

        m_context << u256(1);

        m_context << errorCase;

      }

      else

        m_context.appendConditionalRevert(true);

      break;

    }

    case FunctionType::Kind::SetGas:

    {

      // stack layout: contract_address function_id [gas] [value]

      _functionCall.expression().accept(*this);

      acceptAndConvert(*arguments.front(), *TypeProvider::uint256(), true);

      // Note that function is not the original function, but the ".gas" function.

      // Its values of gasSet and valueSet is equal to the original function's though.

      unsigned stackDepth = (function.gasSet() ? 1u : 0u) + (function.valueSet() ? 1u : 0u);

      if (stackDepth > 0)

        m_context << swapInstruction(stackDepth);

      if (function.gasSet())

        m_context << Instruction::POP;

      break;

    }

    case FunctionType::Kind::SetValue:

      // stack layout: contract_address function_id [gas] [value]

      _functionCall.expression().accept(*this);

      // Note that function is not the original function, but the ".value" function.

      // Its values of gasSet and valueSet is equal to the original function's though.

      if (function.valueSet())

        m_context << Instruction::POP;

      arguments.front()->accept(*this);

      break;

    case FunctionType::Kind::Send:

    case FunctionType::Kind::Transfer:

    {

      _functionCall.expression().accept(*this);

      // Provide the gas stipend manually at first because we may send zero ether.

      // Will be zeroed if we send more than zero ether.

      m_context << u256(evmasm::GasCosts::callStipend);

      acceptAndConvert(*arguments.front(), *function.parameterTypes().front(), true);

      // gas <- gas * !value

      m_context << Instruction::SWAP1 << Instruction::DUP2;

      m_context << Instruction::ISZERO << Instruction::MUL << Instruction::SWAP1;

      FunctionType::Options callOptions;

      callOptions.valueSet = true;

      callOptions.gasSet = true;

      appendExternalFunctionCall(

        FunctionType(

          TypePointers{},

          TypePointers{},

          strings(),

          strings(),

          FunctionType::Kind::BareCall,

          StateMutability::NonPayable,

          nullptr,

          callOptions

        ),

        {},

        false

      );

      if (function.kind() == FunctionType::Kind::Transfer)

      {

        // Check if zero (out of stack or not enough balance).

        m_context << Instruction::ISZERO;

        // Revert message bubbles up.

        m_context.appendConditionalRevert(true);

      }

      break;

    }

    case FunctionType::Kind::Selfdestruct:

      acceptAndConvert(*arguments.front(), *function.parameterTypes().front(), true);

      m_context << Instruction::SELFDESTRUCT;

      break;

    case FunctionType::Kind::Revert:

    {

      if (arguments.empty())

        m_context.appendRevert();

      else

      {

        // function-sel(Error(string)) + encoding

        solAssert(arguments.size() == 1, "");

        solAssert(function.parameterTypes().size() == 1, "");

        if (m_context.revertStrings() == RevertStrings::Strip)

        {

          if (!*arguments.front()->annotation().isPure)

          {

            arguments.front()->accept(*this);

            utils().popStackElement(*arguments.front()->annotation().type);

          }

          m_context.appendRevert();

        }

        else

        {

          arguments.front()->accept(*this);

          utils().revertWithStringData(*arguments.front()->annotation().type);

        }

      }

      break;

    }

    case FunctionType::Kind::KECCAK256:

    {

      solAssert(arguments.size() == 1, "");

      solAssert(!function.padArguments(), "");

      Type const* argType = arguments.front()->annotation().type;

      solAssert(argType, "");

      arguments.front()->accept(*this);

      if (auto const* stringLiteral = dynamic_cast<StringLiteralType const*>(argType))

        // Optimization: Compute keccak256 on string literals at compile-time.

        m_context << u256(keccak256(stringLiteral->value()));

      else if (*argType == *TypeProvider::bytesMemory() || *argType == *TypeProvider::stringMemory())

      {

        // Optimization: If type is bytes or string, then do not encode,

        // but directly compute keccak256 on memory.

        ArrayUtils(m_context).retrieveLength(*TypeProvider::bytesMemory());

        m_context << Instruction::SWAP1 << u256(0x20) << Instruction::ADD;

        m_context << Instruction::KECCAK256;

      }

      else

      {

        utils().fetchFreeMemoryPointer();

        utils().packedEncode({argType}, TypePointers());

        utils().toSizeAfterFreeMemoryPointer();

        m_context << Instruction::KECCAK256;

      }

      break;

    }

    case FunctionType::Kind::Event:

    {

      _functionCall.expression().accept(*this);

      auto const& event = dynamic_cast<EventDefinition const&>(function.declaration());

      unsigned numIndexed = 0;

      TypePointers paramTypes = function.parameterTypes();

      // All indexed arguments go to the stack

      for (size_t arg = arguments.size(); arg > 0; --arg)

        if (event.parameters()[arg - 1]->isIndexed())

        {

          ++numIndexed;

          arguments[arg - 1]->accept(*this);

          if (auto const& referenceType = dynamic_cast<ReferenceType const*>(paramTypes[arg - 1]))

          {

            utils().fetchFreeMemoryPointer();

            utils().packedEncode(

              {arguments[arg - 1]->annotation().type},

              {referenceType}

            );

            utils().toSizeAfterFreeMemoryPointer();

            m_context << Instruction::KECCAK256;

          }

          else

          {

            solAssert(paramTypes[arg - 1]->isValueType(), "");

            if (auto functionType =  dynamic_cast<FunctionType const*>(paramTypes[arg - 1]))

            {

              auto argumentType =

                dynamic_cast<FunctionType const*>(arguments[arg-1]->annotation().type);

              solAssert(

                argumentType &&

                functionType->kind() == FunctionType::Kind::External &&

                argumentType->kind() == FunctionType::Kind::External &&

                !argumentType->bound(),

                ""

              );

              utils().combineExternalFunctionType(true);