/*
This file is part of cpp-ethereum.
cpp-ethereum 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.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2015
* Code generation utils that handle arrays.
*/
#include <libsolidity/ArrayUtils.h>
#include <libevmcore/Instruction.h>
#include <libsolidity/CompilerContext.h>
#include <libsolidity/CompilerUtils.h>
#include <libsolidity/Types.h>
#include <libsolidity/Utils.h>
#include <libsolidity/LValue.h>
using namespace std;
using namespace dev;
using namespace solidity;
void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const
{
// stack layout: [source_ref] target_ref (top)
// need to leave target_ref on the stack at the end
solAssert(_targetType.getLocation() == ArrayType::Location::Storage, "");
solAssert(_targetType.isByteArray(), "Non byte arrays not yet implemented here.");
solAssert(_sourceType.isByteArray(), "Non byte arrays not yet implemented here.");
switch (_sourceType.getLocation())
{
case ArrayType::Location::CallData:
{
// This also assumes that after "length" we only have zeros, i.e. it cannot be used to
// slice a byte array from calldata.
// stack: source_offset source_len target_ref
// fetch old length and convert to words
m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
convertLengthToSize(_targetType);
// stack here: source_offset source_len target_ref target_length_words
// actual array data is stored at SHA3(storage_offset)
m_context << eth::Instruction::DUP2;
CompilerUtils(m_context).computeHashStatic();
// compute target_data_end
m_context << eth::Instruction::DUP1 << eth::Instruction::SWAP2 << eth::Instruction::ADD
<< eth::Instruction::SWAP1;
// stack here: source_offset source_len target_ref target_data_end target_data_ref
// store length (in bytes)
m_context << eth::Instruction::DUP4 << eth::Instruction::DUP1 << eth::Instruction::DUP5
<< eth::Instruction::SSTORE;
// jump to end if length is zero
m_context << eth::Instruction::ISZERO;
eth::AssemblyItem copyLoopEnd = m_context.newTag();
m_context.appendConditionalJumpTo(copyLoopEnd);
// store start offset
m_context << eth::Instruction::DUP5;
// stack now: source_offset source_len target_ref target_data_end target_data_ref calldata_offset
eth::AssemblyItem copyLoopStart = m_context.newTag();
m_context << copyLoopStart
// copy from calldata and store
<< eth::Instruction::DUP1 << eth::Instruction::CALLDATALOAD
<< eth::Instruction::DUP3 << eth::Instruction::SSTORE
// increment target_data_ref by 1
<< eth::Instruction::SWAP1 << u256(1) << eth::Instruction::ADD
// increment calldata_offset by 32
<< eth::Instruction::SWAP1 << u256(32) << eth::Instruction::ADD
// check for loop condition
<< eth::Instruction::DUP1 << eth::Instruction::DUP6 << eth::Instruction::GT;
m_context.appendConditionalJumpTo(copyLoopStart);
m_context << eth::Instruction::POP;
m_context << copyLoopEnd;
// now clear leftover bytes of the old value
// stack now: source_offset source_len target_ref target_data_end target_data_ref
clearStorageLoop(IntegerType(256));
// stack now: source_offset source_len target_ref target_data_end
m_context << eth::Instruction::POP << eth::Instruction::SWAP2
<< eth::Instruction::POP << eth::Instruction::POP;
break;
}
case ArrayType::Location::Storage:
{
// this copies source to target and also clears target if it was larger
// stack: source_ref target_ref
// store target_ref
m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2;
// fetch lengthes
m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD << eth::Instruction::SWAP2
<< eth::Instruction::DUP1 << eth::Instruction::SLOAD;
// stack: target_ref target_len_bytes target_ref source_ref source_len_bytes
// store new target length
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP4 << eth::Instruction::SSTORE;
// compute hashes (data positions)
m_context << eth::Instruction::SWAP2;
CompilerUtils(m_context).computeHashStatic();
m_context << eth::Instruction::SWAP1;
CompilerUtils(m_context).computeHashStatic();
// stack: target_ref target_len_bytes source_len_bytes target_data_pos source_data_pos
// convert lengthes from bytes to storage slots
m_context << u256(31) << u256(32) << eth::Instruction::DUP1 << eth::Instruction::DUP3
<< eth::Instruction::DUP8 << eth::Instruction::ADD << eth::Instruction::DIV
<< eth::Instruction::SWAP2
<< eth::Instruction::DUP6 << eth::Instruction::ADD << eth::Instruction::DIV;
// stack: target_ref target_len_bytes source_len_bytes target_data_pos source_data_pos target_len source_len
// @todo we might be able to go without a third counter
m_context << u256(0);
// stack: target_ref target_len_bytes source_len_bytes target_data_pos source_data_pos target_len source_len counter
eth::AssemblyItem copyLoopStart = m_context.newTag();
m_context << copyLoopStart;
// check for loop condition
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3
<< eth::Instruction::GT << eth::Instruction::ISZERO;
eth::AssemblyItem copyLoopEnd = m_context.newTag();
m_context.appendConditionalJumpTo(copyLoopEnd);
// copy
m_context << eth::Instruction::DUP4 << eth::Instruction::DUP2 << eth::Instruction::ADD
<< eth::Instruction::SLOAD
<< eth::Instruction::DUP6 << eth::Instruction::DUP3 << eth::Instruction::ADD
<< eth::Instruction::SSTORE;
// increment
m_context << u256(1) << eth::Instruction::ADD;
m_context.appendJumpTo(copyLoopStart);
m_context << copyLoopEnd;
// zero-out leftovers in target
// stack: target_ref target_len_bytes source_len_bytes target_data_pos source_data_pos target_len source_len counter
// add counter to target_data_pos
m_context << eth::Instruction::DUP5 << eth::Instruction::ADD
<< eth::Instruction::SWAP5 << eth::Instruction::POP;
// stack: target_ref target_len_bytes target_data_pos_updated target_data_pos source_data_pos target_len source_len
// add length to target_data_pos to get target_data_end
m_context << eth::Instruction::POP << eth::Instruction::DUP3 << eth::Instruction::ADD
<< eth::Instruction::SWAP4
<< eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP;
// stack: target_ref target_data_end target_data_pos_updated
clearStorageLoop(IntegerType(256));
m_context << eth::Instruction::POP;
break;
}
default:
solAssert(false, "Given byte array location not implemented.");
}
}
void ArrayUtils::clearArray(ArrayType const& _type) const
{
solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
if (_type.isDynamicallySized())
clearDynamicArray(_type);
else if (_type.getLength() == 0)
m_context << eth::Instruction::POP;
else if (_type.getLength() < 5) // unroll loop for small arrays @todo choose a good value
{
for (unsigned i = 1; i < _type.getLength(); ++i)
{
StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), false);
m_context << u256(_type.getBaseType()->getStorageSize()) << eth::Instruction::ADD;
}
StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), true);
}
else
{
m_context
<< eth::Instruction::DUP1 << u256(_type.getLength())
<< u256(_type.getBaseType()->getStorageSize())
<< eth::Instruction::MUL << eth::Instruction::ADD << eth::Instruction::SWAP1;
clearStorageLoop(*_type.getBaseType());
m_context << eth::Instruction::POP;
}
}
void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
{
solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
solAssert(_type.isDynamicallySized(), "");
// fetch length
m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
// set length to zero
m_context << u256(0) << eth::Instruction::DUP3 << eth::Instruction::SSTORE;
// stack: ref old_length
convertLengthToSize(_type);
// compute data positions
m_context << eth::Instruction::SWAP1;
CompilerUtils(m_context).computeHashStatic();
// stack: len data_pos (len is in slots for byte array and in items for other arrays)
m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD
<< eth::Instruction::SWAP1;
// stack: data_pos_end data_pos
if (_type.isByteArray())
clearStorageLoop(IntegerType(256));
else
clearStorageLoop(*_type.getBaseType());
// cleanup
m_context << eth::Instruction::POP;
}
void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const
{
solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
solAssert(_type.isDynamicallySized(), "");
eth::AssemblyItem resizeEnd = m_context.newTag();
// stack: ref new_length
// fetch old length
m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD;
// stack: ref new_length old_length
// store new length
m_context << eth::Instruction::DUP2 << eth::Instruction::DUP4 << eth::Instruction::SSTORE;
// skip if size is not reduced
m_context << eth::Instruction::DUP2 << eth::Instruction::DUP2
<< eth::Instruction::ISZERO << eth::Instruction::GT;
m_context.appendConditionalJumpTo(resizeEnd);
// size reduced, clear the end of the array
// stack: ref new_length old_length
convertLengthToSize(_type);
m_context << eth::Instruction::DUP2;
convertLengthToSize(_type);
// stack: ref new_length old_size new_size
// compute data positions
m_context << eth::Instruction::DUP4;
CompilerUtils(m_context).computeHashStatic();
// stack: ref new_length old_size new_size data_pos
m_context << eth::Instruction::SWAP2 << eth::Instruction::DUP3 << eth::Instruction::ADD;
// stack: ref new_length data_pos new_size delete_end
m_context << eth::Instruction::SWAP2 << eth::Instruction::ADD;
// stack: ref new_length delete_end delete_start
if (_type.isByteArray())
clearStorageLoop(IntegerType(256));
else
clearStorageLoop(*_type.getBaseType());
m_context << resizeEnd;
// cleanup
m_context << eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP;
}
void ArrayUtils::clearStorageLoop(Type const& _type) const
{
// stack: end_pos pos
eth::AssemblyItem loopStart = m_context.newTag();
m_context << loopStart;
// check for loop condition
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3
<< eth::Instruction::GT << eth::Instruction::ISZERO;
eth::AssemblyItem zeroLoopEnd = m_context.newTag();
m_context.appendConditionalJumpTo(zeroLoopEnd);
// delete
StorageItem(m_context, _type).setToZero(SourceLocation(), false);
// increment
m_context << u256(1) << eth::Instruction::ADD;
m_context.appendJumpTo(loopStart);
// cleanup
m_context << zeroLoopEnd;
m_context << eth::Instruction::POP;
}
void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType) const
{
if (_arrayType.isByteArray())
m_context << u256(31) << eth::Instruction::ADD
<< u256(32) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
else if (_arrayType.getBaseType()->getStorageSize() > 1)
m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL;
}
