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323 lines
13 KiB
323 lines
13 KiB
/*
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This file is part of cpp-ethereum.
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cpp-ethereum is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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cpp-ethereum is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @author Christian <c@ethdev.com>
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* @date 2015
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* Code generation utils that handle arrays.
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*/
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#include <libsolidity/ArrayUtils.h>
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#include <libevmcore/Instruction.h>
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#include <libsolidity/CompilerContext.h>
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#include <libsolidity/CompilerUtils.h>
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#include <libsolidity/Types.h>
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#include <libsolidity/Utils.h>
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#include <libsolidity/LValue.h>
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using namespace std;
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using namespace dev;
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using namespace solidity;
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void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const
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{
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// stack layout: [source_ref] target_ref (top)
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// need to leave target_ref on the stack at the end
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solAssert(_targetType.getLocation() == ArrayType::Location::Storage, "");
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IntegerType uint256(256);
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Type const* targetBaseType = _targetType.isByteArray() ? &uint256 : &(*_targetType.getBaseType());
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Type const* sourceBaseType = _sourceType.isByteArray() ? &uint256 : &(*_sourceType.getBaseType());
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switch (_sourceType.getLocation())
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{
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case ArrayType::Location::CallData:
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{
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solAssert(_targetType.isByteArray(), "Non byte arrays not yet implemented here.");
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solAssert(_sourceType.isByteArray(), "Non byte arrays not yet implemented here.");
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// This also assumes that after "length" we only have zeros, i.e. it cannot be used to
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// slice a byte array from calldata.
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// stack: source_offset source_len target_ref
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// fetch old length and convert to words
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m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
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convertLengthToSize(_targetType);
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// stack here: source_offset source_len target_ref target_length_words
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// actual array data is stored at SHA3(storage_offset)
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m_context << eth::Instruction::DUP2;
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CompilerUtils(m_context).computeHashStatic();
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// compute target_data_end
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m_context << eth::Instruction::DUP1 << eth::Instruction::SWAP2 << eth::Instruction::ADD
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<< eth::Instruction::SWAP1;
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// stack here: source_offset source_len target_ref target_data_end target_data_ref
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// store length (in bytes)
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m_context << eth::Instruction::DUP4 << eth::Instruction::DUP1 << eth::Instruction::DUP5
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<< eth::Instruction::SSTORE;
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// jump to end if length is zero
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m_context << eth::Instruction::ISZERO;
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eth::AssemblyItem copyLoopEnd = m_context.newTag();
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m_context.appendConditionalJumpTo(copyLoopEnd);
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// add length to source offset
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m_context << eth::Instruction::DUP5 << eth::Instruction::DUP5 << eth::Instruction::ADD;
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// stack now: source_offset source_len target_ref target_data_end target_data_ref source_end
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// store start offset
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m_context << eth::Instruction::DUP6;
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// stack now: source_offset source_len target_ref target_data_end target_data_ref source_end calldata_offset
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eth::AssemblyItem copyLoopStart = m_context.newTag();
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m_context << copyLoopStart
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// copy from calldata and store
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<< eth::Instruction::DUP1 << eth::Instruction::CALLDATALOAD
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<< eth::Instruction::DUP4 << eth::Instruction::SSTORE
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// increment target_data_ref by 1
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<< eth::Instruction::SWAP2 << u256(1) << eth::Instruction::ADD
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// increment calldata_offset by 32
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<< eth::Instruction::SWAP2 << u256(32) << eth::Instruction::ADD
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// check for loop condition
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<< eth::Instruction::DUP1 << eth::Instruction::DUP3 << eth::Instruction::GT;
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m_context.appendConditionalJumpTo(copyLoopStart);
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m_context << eth::Instruction::POP << eth::Instruction::POP;
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m_context << copyLoopEnd;
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// now clear leftover bytes of the old value
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// stack now: source_offset source_len target_ref target_data_end target_data_ref
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clearStorageLoop(IntegerType(256));
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// stack now: source_offset source_len target_ref target_data_end
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m_context << eth::Instruction::POP << eth::Instruction::SWAP2
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<< eth::Instruction::POP << eth::Instruction::POP;
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break;
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}
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case ArrayType::Location::Storage:
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{
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// this copies source to target and also clears target if it was larger
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solAssert(sourceBaseType->getStorageSize() == targetBaseType->getStorageSize(),
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"Copying with different storage sizes not yet implemented.");
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// stack: source_ref target_ref
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// store target_ref
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m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2;
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// stack: target_ref source_ref target_ref
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// fetch lengthes
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retrieveLength(_targetType);
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m_context << eth::Instruction::SWAP2;
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// stack: target_ref target_len target_ref source_ref
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retrieveLength(_sourceType);
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// stack: target_ref target_len target_ref source_ref source_len
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if (_targetType.isDynamicallySized())
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// store new target length
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m_context << eth::Instruction::DUP1 << eth::Instruction::DUP4 << eth::Instruction::SSTORE;
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// compute hashes (data positions)
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m_context << eth::Instruction::SWAP2;
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if (_targetType.isDynamicallySized())
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CompilerUtils(m_context).computeHashStatic();
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m_context << eth::Instruction::SWAP1;
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if (_sourceType.isDynamicallySized())
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CompilerUtils(m_context).computeHashStatic();
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// stack: target_ref target_len source_len target_data_pos source_data_pos
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m_context << eth::Instruction::DUP4;
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convertLengthToSize(_sourceType);
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m_context << eth::Instruction::DUP4;
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convertLengthToSize(_sourceType);
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// stack: target_ref target_len source_len target_data_pos source_data_pos target_size source_size
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// @todo we might be able to go without a third counter
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m_context << u256(0);
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// stack: target_ref target_len source_len target_data_pos source_data_pos target_size source_size counter
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eth::AssemblyItem copyLoopStart = m_context.newTag();
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m_context << copyLoopStart;
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// check for loop condition
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m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3
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<< eth::Instruction::GT << eth::Instruction::ISZERO;
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eth::AssemblyItem copyLoopEnd = m_context.newTag();
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m_context.appendConditionalJumpTo(copyLoopEnd);
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// copy
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m_context << eth::Instruction::DUP4 << eth::Instruction::DUP2 << eth::Instruction::ADD;
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StorageItem(m_context, *sourceBaseType).retrieveValue(SourceLocation(), true);
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m_context << eth::dupInstruction(5 + sourceBaseType->getSizeOnStack())
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<< eth::dupInstruction(2 + sourceBaseType->getSizeOnStack()) << eth::Instruction::ADD;
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StorageItem(m_context, *targetBaseType).storeValue(*sourceBaseType, SourceLocation(), true);
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// increment
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m_context << targetBaseType->getStorageSize() << eth::Instruction::ADD;
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m_context.appendJumpTo(copyLoopStart);
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m_context << copyLoopEnd;
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// zero-out leftovers in target
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// stack: target_ref target_len source_len target_data_pos source_data_pos target_size source_size counter
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// add counter to target_data_pos
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m_context << eth::Instruction::DUP5 << eth::Instruction::ADD
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<< eth::Instruction::SWAP5 << eth::Instruction::POP;
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// stack: target_ref target_len target_data_pos_updated target_data_pos source_data_pos target_size source_size
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// add size to target_data_pos to get target_data_end
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m_context << eth::Instruction::POP << eth::Instruction::DUP3 << eth::Instruction::ADD
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<< eth::Instruction::SWAP4
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<< eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP;
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// stack: target_ref target_data_end target_data_pos_updated
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clearStorageLoop(*targetBaseType);
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m_context << eth::Instruction::POP;
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break;
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}
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default:
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solAssert(false, "Given byte array location not implemented.");
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}
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}
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void ArrayUtils::clearArray(ArrayType const& _type) const
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{
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solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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if (_type.isDynamicallySized())
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clearDynamicArray(_type);
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else if (_type.getLength() == 0)
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m_context << eth::Instruction::POP;
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else if (_type.getLength() < 5) // unroll loop for small arrays @todo choose a good value
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{
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solAssert(!_type.isByteArray(), "");
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for (unsigned i = 1; i < _type.getLength(); ++i)
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{
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StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), false);
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m_context << u256(_type.getBaseType()->getStorageSize()) << eth::Instruction::ADD;
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}
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StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), true);
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}
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else
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{
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solAssert(!_type.isByteArray(), "");
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m_context
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<< eth::Instruction::DUP1 << u256(_type.getLength())
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<< u256(_type.getBaseType()->getStorageSize())
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<< eth::Instruction::MUL << eth::Instruction::ADD << eth::Instruction::SWAP1;
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clearStorageLoop(*_type.getBaseType());
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m_context << eth::Instruction::POP;
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}
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}
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void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
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{
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solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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solAssert(_type.isDynamicallySized(), "");
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// fetch length
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m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
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// set length to zero
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m_context << u256(0) << eth::Instruction::DUP3 << eth::Instruction::SSTORE;
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// stack: ref old_length
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convertLengthToSize(_type);
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// compute data positions
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m_context << eth::Instruction::SWAP1;
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CompilerUtils(m_context).computeHashStatic();
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// stack: len data_pos (len is in slots for byte array and in items for other arrays)
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m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD
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<< eth::Instruction::SWAP1;
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// stack: data_pos_end data_pos
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if (_type.isByteArray())
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clearStorageLoop(IntegerType(256));
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else
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clearStorageLoop(*_type.getBaseType());
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// cleanup
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m_context << eth::Instruction::POP;
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}
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void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const
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{
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solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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solAssert(_type.isDynamicallySized(), "");
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eth::AssemblyItem resizeEnd = m_context.newTag();
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// stack: ref new_length
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// fetch old length
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m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD;
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// stack: ref new_length old_length
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// store new length
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m_context << eth::Instruction::DUP2 << eth::Instruction::DUP4 << eth::Instruction::SSTORE;
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// skip if size is not reduced
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m_context << eth::Instruction::DUP2 << eth::Instruction::DUP2
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<< eth::Instruction::ISZERO << eth::Instruction::GT;
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m_context.appendConditionalJumpTo(resizeEnd);
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// size reduced, clear the end of the array
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// stack: ref new_length old_length
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convertLengthToSize(_type);
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m_context << eth::Instruction::DUP2;
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convertLengthToSize(_type);
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// stack: ref new_length old_size new_size
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// compute data positions
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m_context << eth::Instruction::DUP4;
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CompilerUtils(m_context).computeHashStatic();
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// stack: ref new_length old_size new_size data_pos
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m_context << eth::Instruction::SWAP2 << eth::Instruction::DUP3 << eth::Instruction::ADD;
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// stack: ref new_length data_pos new_size delete_end
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m_context << eth::Instruction::SWAP2 << eth::Instruction::ADD;
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// stack: ref new_length delete_end delete_start
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if (_type.isByteArray())
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clearStorageLoop(IntegerType(256));
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else
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clearStorageLoop(*_type.getBaseType());
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m_context << resizeEnd;
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// cleanup
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m_context << eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP;
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}
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void ArrayUtils::clearStorageLoop(Type const& _type) const
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{
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// stack: end_pos pos
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eth::AssemblyItem loopStart = m_context.newTag();
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m_context << loopStart;
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// check for loop condition
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m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3
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<< eth::Instruction::GT << eth::Instruction::ISZERO;
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eth::AssemblyItem zeroLoopEnd = m_context.newTag();
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m_context.appendConditionalJumpTo(zeroLoopEnd);
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// delete
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StorageItem(m_context, _type).setToZero(SourceLocation(), false);
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// increment
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m_context << u256(1) << eth::Instruction::ADD;
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m_context.appendJumpTo(loopStart);
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// cleanup
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m_context << zeroLoopEnd;
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m_context << eth::Instruction::POP;
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}
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void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType) const
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{
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if (_arrayType.isByteArray())
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m_context << u256(31) << eth::Instruction::ADD
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<< u256(32) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
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else if (_arrayType.getBaseType()->getStorageSize() > 1)
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m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL;
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}
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void ArrayUtils::retrieveLength(ArrayType const& _arrayType) const
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{
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if (!_arrayType.isDynamicallySized())
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m_context << _arrayType.getLength();
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else
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{
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m_context << eth::Instruction::DUP1;
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switch (_arrayType.getLocation())
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{
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case ArrayType::Location::CallData:
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// length is stored on the stack
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break;
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case ArrayType::Location::Memory:
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m_context << eth::Instruction::MLOAD;
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break;
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case ArrayType::Location::Storage:
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m_context << eth::Instruction::SLOAD;
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break;
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}
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}
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}
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