Method copyArrayToStorage

libsolidity/codegen/ArrayUtils.cpp:44–108

using namespace solidity::langutil;

void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const
{
	// this copies source to target and also clears target if it was larger
	// need to leave "target_ref target_byte_off" on the stack at the end

	// stack layout: source_ref [source length] target_ref (top)
	solAssert(_targetType.location() == DataLocation::Storage, "");

	// TODO unroll loop for small sizes

	bool fromCalldata = _sourceType.location() == DataLocation::CallData;
	bool haveSourceLengthOnStack = fromCalldata && _sourceType.isDynamicallySized();

	for (unsigned i = _sourceType.sizeOnStack(); i > 0; --i)
		m_context << swapInstruction(i);
	// stack: target_ref source_ref [source_length]

	if (_sourceType.baseType()->category() == Type::Category::Array)
	{
		// TODO: This limitation can now be removed since we use Yul utility functions that handle nested arrays correctly.
		// The old inline assembly implementation couldn't handle nested calldata dynamic arrays, but the Yul functions
		// support them through recursive calls. We keep this check temporarily for backward compatibility.
		auto const& sourceBaseArrayType = dynamic_cast<ArrayType const&>(*_sourceType.baseType());
		solUnimplementedAssert(
			!fromCalldata ||
			!_sourceType.isDynamicallyEncoded() ||
			!sourceBaseArrayType.isDynamicallySized(),
			"Copying nested calldata dynamic arrays to storage is not implemented in the old code generator."
		);
	}
	else
	{
		// TODO: This limitation can now be removed since we use Yul utility functions that handle non-value types correctly.
		// The old inline assembly implementation couldn't handle copying arrays of non-value types from memory or calldata to storage,
		// but the Yul functions support them. We keep this check temporarily for backward compatibility.
		bool fromMemoryOrCalldata = _sourceType.location() == DataLocation::Memory || _sourceType.location() == DataLocation::CallData;
		solUnimplementedAssert(
			_sourceType.baseType()->isValueType() || !fromMemoryOrCalldata,
			"Copying of type " + _sourceType.toString(false) + " to storage is not supported in legacy (only supported by the IR pipeline). " +
			"Hint: try compiling with `--via-ir` (CLI) or the equivalent `viaIR: true` (Standard JSON)."
		);
	}

	if (haveSourceLengthOnStack)
	{
		// stack: target_ref source_ref source_length
		m_context << Instruction::SWAP1;
		// stack: target_ref source_length source_ref
		m_context << Instruction::DUP3;
		// stack: target_ref source_length source_ref target_ref
	}
	else
	{
		// stack: target_ref source_ref
		m_context << Instruction::DUP2;
		// stack: target_ref source_ref target_ref
	}