/* 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 . */ /** * @author Christian * @date 2015 * Code generation utils that handle arrays. */ #include #include #include #include #include #include #include using namespace std; using namespace dev; using namespace solidity; 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, ""); IntegerType uint256(256); Type const* targetBaseType = _targetType.isByteArray() ? &uint256 : &(*_targetType.baseType()); Type const* sourceBaseType = _sourceType.isByteArray() ? &uint256 : &(*_sourceType.baseType()); // TODO unroll loop for small sizes bool sourceIsStorage = _sourceType.location() == DataLocation::Storage; bool fromCalldata = _sourceType.location() == DataLocation::CallData; bool directCopy = sourceIsStorage && sourceBaseType->isValueType() && *sourceBaseType == *targetBaseType; bool haveByteOffsetSource = !directCopy && sourceIsStorage && sourceBaseType->storageBytes() <= 16; bool haveByteOffsetTarget = !directCopy && targetBaseType->storageBytes() <= 16; unsigned byteOffsetSize = (haveByteOffsetSource ? 1 : 0) + (haveByteOffsetTarget ? 1 : 0); // stack: source_ref [source_length] target_ref // store target_ref for (unsigned i = _sourceType.sizeOnStack(); i > 0; --i) m_context << swapInstruction(i); // stack: target_ref source_ref [source_length] // stack: target_ref source_ref [source_length] // retrieve source length if (_sourceType.location() != DataLocation::CallData || !_sourceType.isDynamicallySized()) retrieveLength(_sourceType); // otherwise, length is already there if (_sourceType.location() == DataLocation::Memory && _sourceType.isDynamicallySized()) { // increment source pointer to point to data m_context << Instruction::SWAP1 << u256(0x20); m_context << Instruction::ADD << Instruction::SWAP1; } // stack: target_ref source_ref source_length m_context << Instruction::DUP3; // stack: target_ref source_ref source_length target_ref retrieveLength(_targetType); // stack: target_ref source_ref source_length target_ref target_length if (_targetType.isDynamicallySized()) // store new target length if (!_targetType.isByteArray()) // Otherwise, length will be stored below. m_context << Instruction::DUP3 << Instruction::DUP3 << Instruction::SSTORE; if (sourceBaseType->category() == Type::Category::Mapping) { solAssert(targetBaseType->category() == Type::Category::Mapping, ""); solAssert(_sourceType.location() == DataLocation::Storage, ""); // nothing to copy m_context << Instruction::POP << Instruction::POP << Instruction::POP << Instruction::POP; return; } // stack: target_ref source_ref source_length target_ref target_length // compute hashes (data positions) m_context << Instruction::SWAP1; if (_targetType.isDynamicallySized()) CompilerUtils(m_context).computeHashStatic(); // stack: target_ref source_ref source_length target_length target_data_pos m_context << Instruction::SWAP1; convertLengthToSize(_targetType); m_context << Instruction::DUP2 << Instruction::ADD; // stack: target_ref source_ref source_length target_data_pos target_data_end m_context << Instruction::SWAP3; // stack: target_ref target_data_end source_length target_data_pos source_ref eth::AssemblyItem copyLoopEndWithoutByteOffset = m_context.newTag(); // special case for short byte arrays: Store them together with their length. if (_targetType.isByteArray()) { // stack: target_ref target_data_end source_length target_data_pos source_ref m_context << Instruction::DUP3 << u256(31) << Instruction::LT; eth::AssemblyItem longByteArray = m_context.appendConditionalJump(); // store the short byte array solAssert(_sourceType.isByteArray(), ""); if (_sourceType.location() == DataLocation::Storage) { // just copy the slot, it contains length and data m_context << Instruction::DUP1 << Instruction::SLOAD; m_context << Instruction::DUP6 << Instruction::SSTORE; } else { m_context << Instruction::DUP1; CompilerUtils(m_context).loadFromMemoryDynamic(*sourceBaseType, fromCalldata, true, false); // stack: target_ref target_data_end source_length target_data_pos source_ref value // clear the lower-order byte - which will hold the length m_context << u256(0xff) << Instruction::NOT << Instruction::AND; // fetch the length and shift it left by one m_context << Instruction::DUP4 << Instruction::DUP1 << Instruction::ADD; // combine value and length and store them m_context << Instruction::OR << Instruction::DUP6 << Instruction::SSTORE; } // end of special case, jump right into cleaning target data area m_context.appendJumpTo(copyLoopEndWithoutByteOffset); m_context << longByteArray; // Store length (2*length+1) m_context << Instruction::DUP3 << Instruction::DUP1 << Instruction::ADD; m_context << u256(1) << Instruction::ADD; m_context << Instruction::DUP6 << Instruction::SSTORE; } // skip copying if source length is zero m_context << Instruction::DUP3 << Instruction::ISZERO; m_context.appendConditionalJumpTo(copyLoopEndWithoutByteOffset); if (_sourceType.location() == DataLocation::Storage && _sourceType.isDynamicallySized()) CompilerUtils(m_context).computeHashStatic(); // stack: target_ref target_data_end source_length target_data_pos source_data_pos m_context << Instruction::SWAP2; convertLengthToSize(_sourceType); m_context << Instruction::DUP3 << Instruction::ADD; // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end if (haveByteOffsetTarget) m_context << u256(0); if (haveByteOffsetSource) m_context << u256(0); // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] eth::AssemblyItem copyLoopStart = m_context.newTag(); m_context << copyLoopStart; // check for loop condition m_context << dupInstruction(3 + byteOffsetSize) << dupInstruction(2 + byteOffsetSize) << Instruction::GT << Instruction::ISZERO; eth::AssemblyItem copyLoopEnd = m_context.appendConditionalJump(); // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] // copy if (sourceBaseType->category() == Type::Category::Array) { solAssert(byteOffsetSize == 0, "Byte offset for array as base type."); auto const& sourceBaseArrayType = dynamic_cast(*sourceBaseType); m_context << Instruction::DUP3; if (sourceBaseArrayType.location() == DataLocation::Memory) m_context << Instruction::MLOAD; m_context << Instruction::DUP3; copyArrayToStorage(dynamic_cast(*targetBaseType), sourceBaseArrayType); m_context << Instruction::POP; } else if (directCopy) { solAssert(byteOffsetSize == 0, "Byte offset for direct copy."); m_context << Instruction::DUP3 << Instruction::SLOAD << Instruction::DUP3 << Instruction::SSTORE; } else { // Note that we have to copy each element on its own in case conversion is involved. // We might copy too much if there is padding at the last element, but this way end // checking is easier. // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] m_context << dupInstruction(3 + byteOffsetSize); if (_sourceType.location() == DataLocation::Storage) { if (haveByteOffsetSource) m_context << Instruction::DUP2; else m_context << u256(0); StorageItem(m_context, *sourceBaseType).retrieveValue(SourceLocation(), true); } else if (sourceBaseType->isValueType()) CompilerUtils(m_context).loadFromMemoryDynamic(*sourceBaseType, fromCalldata, true, false); else solAssert(false, "Copying of type " + _sourceType.toString(false) + " to storage not yet supported."); // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] ... solAssert( 2 + byteOffsetSize + sourceBaseType->sizeOnStack() <= 16, "Stack too deep, try removing local variables." ); // fetch target storage reference m_context << dupInstruction(2 + byteOffsetSize + sourceBaseType->sizeOnStack()); if (haveByteOffsetTarget) m_context << dupInstruction(1 + byteOffsetSize + sourceBaseType->sizeOnStack()); else m_context << u256(0); StorageItem(m_context, *targetBaseType).storeValue(*sourceBaseType, SourceLocation(), true); } // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] // increment source if (haveByteOffsetSource) incrementByteOffset(sourceBaseType->storageBytes(), 1, haveByteOffsetTarget ? 5 : 4); else { m_context << swapInstruction(2 + byteOffsetSize); if (sourceIsStorage) m_context << sourceBaseType->storageSize(); else if (_sourceType.location() == DataLocation::Memory) m_context << sourceBaseType->memoryHeadSize(); else m_context << sourceBaseType->calldataEncodedSize(true); m_context << Instruction::ADD << swapInstruction(2 + byteOffsetSize); } // increment target if (haveByteOffsetTarget) incrementByteOffset(targetBaseType->storageBytes(), byteOffsetSize, byteOffsetSize + 2); else m_context << swapInstruction(1 + byteOffsetSize) << targetBaseType->storageSize() << Instruction::ADD << swapInstruction(1 + byteOffsetSize); m_context.appendJumpTo(copyLoopStart); m_context << copyLoopEnd; if (haveByteOffsetTarget) { // clear elements that might be left over in the current slot in target // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end target_byte_offset [source_byte_offset] m_context << dupInstruction(byteOffsetSize) << Instruction::ISZERO; eth::AssemblyItem copyCleanupLoopEnd = m_context.appendConditionalJump(); m_context << dupInstruction(2 + byteOffsetSize) << dupInstruction(1 + byteOffsetSize); StorageItem(m_context, *targetBaseType).setToZero(SourceLocation(), true); incrementByteOffset(targetBaseType->storageBytes(), byteOffsetSize, byteOffsetSize + 2); m_context.appendJumpTo(copyLoopEnd); m_context << copyCleanupLoopEnd; m_context << Instruction::POP; // might pop the source, but then target is popped next } if (haveByteOffsetSource) m_context << Instruction::POP; m_context << copyLoopEndWithoutByteOffset; // zero-out leftovers in target // stack: target_ref target_data_end source_data_pos target_data_pos_updated source_data_end m_context << Instruction::POP << Instruction::SWAP1 << Instruction::POP; // stack: target_ref target_data_end target_data_pos_updated clearStorageLoop(*targetBaseType); m_context << Instruction::POP; } void ArrayUtils::copyArrayToMemory(ArrayType const& _sourceType, bool _padToWordBoundaries) const { solAssert( !_sourceType.baseType()->isDynamicallySized(), "Nested dynamic arrays not implemented here." ); CompilerUtils utils(m_context); unsigned baseSize = 1; if (!_sourceType.isByteArray()) // We always pad the elements, regardless of _padToWordBoundaries. baseSize = _sourceType.baseType()->calldataEncodedSize(); if (_sourceType.location() == DataLocation::CallData) { if (!_sourceType.isDynamicallySized()) m_context << _sourceType.length(); if (baseSize > 1) m_context << u256(baseSize) << Instruction::MUL; // stack: target source_offset source_len m_context << Instruction::DUP1 << Instruction::DUP3 << Instruction::DUP5; // stack: target source_offset source_len source_len source_offset target m_context << Instruction::CALLDATACOPY; m_context << Instruction::DUP3 << Instruction::ADD; m_context << Instruction::SWAP2 << Instruction::POP << Instruction::POP; } else if (_sourceType.location() == DataLocation::Memory) { retrieveLength(_sourceType); // stack: target source length if (!_sourceType.baseType()->isValueType()) { // copy using a loop m_context << u256(0) << Instruction::SWAP3; // stack: counter source length target auto repeat = m_context.newTag(); m_context << repeat; m_context << Instruction::DUP2 << Instruction::DUP5; m_context << Instruction::LT << Instruction::ISZERO; auto loopEnd = m_context.appendConditionalJump(); m_context << Instruction::DUP3 << Instruction::DUP5; accessIndex(_sourceType, false); MemoryItem(m_context, *_sourceType.baseType(), true).retrieveValue(SourceLocation(), true); if (auto baseArray = dynamic_cast(_sourceType.baseType().get())) copyArrayToMemory(*baseArray, _padToWordBoundaries); else utils.storeInMemoryDynamic(*_sourceType.baseType()); m_context << Instruction::SWAP3 << u256(1) << Instruction::ADD; m_context << Instruction::SWAP3; m_context.appendJumpTo(repeat); m_context << loopEnd; m_context << Instruction::SWAP3; utils.popStackSlots(3); // stack: updated_target_pos return; } // memcpy using the built-in contract if (_sourceType.isDynamicallySized()) { // change pointer to data part m_context << Instruction::SWAP1 << u256(32) << Instruction::ADD; m_context << Instruction::SWAP1; } // convert length to size if (baseSize > 1) m_context << u256(baseSize) << Instruction::MUL; // stack: //@TODO do not use ::CALL if less than 32 bytes? m_context << Instruction::DUP1 << Instruction::DUP4 << Instruction::DUP4; utils.memoryCopy(); m_context << Instruction::SWAP1 << Instruction::POP; // stack: bool paddingNeeded = false; if (_sourceType.isDynamicallySized()) paddingNeeded = _padToWordBoundaries && ((baseSize % 32) != 0); else paddingNeeded = _padToWordBoundaries && (((_sourceType.length() * baseSize) % 32) != 0); if (paddingNeeded) { // stack: m_context << Instruction::SWAP1 << Instruction::DUP2 << Instruction::ADD; // stack: m_context << Instruction::SWAP1 << u256(31) << Instruction::AND; // stack: eth::AssemblyItem skip = m_context.newTag(); if (_sourceType.isDynamicallySized()) { m_context << Instruction::DUP1 << Instruction::ISZERO; m_context.appendConditionalJumpTo(skip); } // round off, load from there. // stack m_context << Instruction::DUP1 << Instruction::DUP3; m_context << Instruction::SUB; // stack: target+size remainder m_context << Instruction::DUP1 << Instruction::MLOAD; // Now we AND it with ~(2**(8 * (32 - remainder)) - 1) m_context << u256(1); m_context << Instruction::DUP4 << u256(32) << Instruction::SUB; // stack: ... 1 <32 - remainder> m_context << u256(0x100) << Instruction::EXP << Instruction::SUB; m_context << Instruction::NOT << Instruction::AND; // stack: target+size remainder target+size-remainder m_context << Instruction::DUP2 << Instruction::MSTORE; // stack: target+size remainder target+size-remainder m_context << u256(32) << Instruction::ADD; // stack: target+size remainder m_context << Instruction::SWAP2 << Instruction::POP; if (_sourceType.isDynamicallySized()) m_context << skip.tag(); // stack m_context << Instruction::POP; } else // stack: m_context << Instruction::ADD; } else { solAssert(_sourceType.location() == DataLocation::Storage, ""); unsigned storageBytes = _sourceType.baseType()->storageBytes(); u256 storageSize = _sourceType.baseType()->storageSize(); solAssert(storageSize > 1 || (storageSize == 1 && storageBytes > 0), ""); retrieveLength(_sourceType); // stack here: memory_offset storage_offset length // jump to end if length is zero m_context << Instruction::DUP1 << Instruction::ISZERO; eth::AssemblyItem loopEnd = m_context.appendConditionalJump(); // Special case for tightly-stored byte arrays if (_sourceType.isByteArray()) { // stack here: memory_offset storage_offset length m_context << Instruction::DUP1 << u256(31) << Instruction::LT; eth::AssemblyItem longByteArray = m_context.appendConditionalJump(); // store the short byte array (discard lower-order byte) m_context << u256(0x100) << Instruction::DUP1; m_context << Instruction::DUP4 << Instruction::SLOAD; m_context << Instruction::DIV << Instruction::MUL; m_context << Instruction::DUP4 << Instruction::MSTORE; // stack here: memory_offset storage_offset length // add 32 or length to memory offset m_context << Instruction::SWAP2; if (_padToWordBoundaries) m_context << u256(32); else m_context << Instruction::DUP3; m_context << Instruction::ADD; m_context << Instruction::SWAP2; m_context.appendJumpTo(loopEnd); m_context << longByteArray; } // compute memory end offset if (baseSize > 1) // convert length to memory size m_context << u256(baseSize) << Instruction::MUL; m_context << Instruction::DUP3 << Instruction::ADD << Instruction::SWAP2; if (_sourceType.isDynamicallySized()) { // actual array data is stored at SHA3(storage_offset) m_context << Instruction::SWAP1; utils.computeHashStatic(); m_context << Instruction::SWAP1; } // stack here: memory_end_offset storage_data_offset memory_offset bool haveByteOffset = !_sourceType.isByteArray() && storageBytes <= 16; if (haveByteOffset) m_context << u256(0) << Instruction::SWAP1; // stack here: memory_end_offset storage_data_offset [storage_byte_offset] memory_offset eth::AssemblyItem loopStart = m_context.newTag(); m_context << loopStart; // load and store if (_sourceType.isByteArray()) { // Packed both in storage and memory. m_context << Instruction::DUP2 << Instruction::SLOAD; m_context << Instruction::DUP2 << Instruction::MSTORE; // increment storage_data_offset by 1 m_context << Instruction::SWAP1 << u256(1) << Instruction::ADD; // increment memory offset by 32 m_context << Instruction::SWAP1 << u256(32) << Instruction::ADD; } else { // stack here: memory_end_offset storage_data_offset [storage_byte_offset] memory_offset if (haveByteOffset) m_context << Instruction::DUP3 << Instruction::DUP3; else m_context << Instruction::DUP2 << u256(0); StorageItem(m_context, *_sourceType.baseType()).retrieveValue(SourceLocation(), true); if (auto baseArray = dynamic_cast(_sourceType.baseType().get())) copyArrayToMemory(*baseArray, _padToWordBoundaries); else utils.storeInMemoryDynamic(*_sourceType.baseType()); // increment storage_data_offset and byte offset if (haveByteOffset) incrementByteOffset(storageBytes, 2, 3); else { m_context << Instruction::SWAP1; m_context << storageSize << Instruction::ADD; m_context << Instruction::SWAP1; } } // check for loop condition m_context << Instruction::DUP1 << dupInstruction(haveByteOffset ? 5 : 4); m_context << Instruction::GT; m_context.appendConditionalJumpTo(loopStart); // stack here: memory_end_offset storage_data_offset [storage_byte_offset] memory_offset if (haveByteOffset) m_context << Instruction::SWAP1 << Instruction::POP; if (_padToWordBoundaries && baseSize % 32 != 0) { // memory_end_offset - start is the actual length (we want to compute the ceil of). // memory_offset - start is its next multiple of 32, but it might be off by 32. // so we compute: memory_end_offset += (memory_offset - memory_end_offest) & 31 m_context << Instruction::DUP3 << Instruction::SWAP1 << Instruction::SUB; m_context << u256(31) << Instruction::AND; m_context << Instruction::DUP3 << Instruction::ADD; m_context << Instruction::SWAP2; } m_context << loopEnd << Instruction::POP << Instruction::POP; } } void ArrayUtils::clearArray(ArrayType const& _type) const { unsigned stackHeightStart = m_context.stackHeight(); solAssert(_type.location() == DataLocation::Storage, ""); if (_type.baseType()->storageBytes() < 32) { solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type."); solAssert(_type.baseType()->storageSize() <= 1, "Invalid storage size for type."); } if (_type.baseType()->isValueType()) solAssert(_type.baseType()->storageSize() <= 1, "Invalid size for value type."); m_context << Instruction::POP; // remove byte offset if (_type.isDynamicallySized()) clearDynamicArray(_type); else if (_type.length() == 0 || _type.baseType()->category() == Type::Category::Mapping) m_context << Instruction::POP; else if (_type.baseType()->isValueType() && _type.storageSize() <= 5) { // unroll loop for small arrays @todo choose a good value // Note that we loop over storage slots here, not elements. for (unsigned i = 1; i < _type.storageSize(); ++i) m_context << u256(0) << Instruction::DUP2 << Instruction::SSTORE << u256(1) << Instruction::ADD; m_context << u256(0) << Instruction::SWAP1 << Instruction::SSTORE; } else if (!_type.baseType()->isValueType() && _type.length() <= 4) { // unroll loop for small arrays @todo choose a good value solAssert(_type.baseType()->storageBytes() >= 32, "Invalid storage size."); for (unsigned i = 1; i < _type.length(); ++i) { m_context << u256(0); StorageItem(m_context, *_type.baseType()).setToZero(SourceLocation(), false); m_context << Instruction::POP << u256(_type.baseType()->storageSize()) << Instruction::ADD; } m_context << u256(0); StorageItem(m_context, *_type.baseType()).setToZero(SourceLocation(), true); } else { m_context << Instruction::DUP1 << _type.length(); convertLengthToSize(_type); m_context << Instruction::ADD << Instruction::SWAP1; if (_type.baseType()->storageBytes() < 32) clearStorageLoop(IntegerType(256)); else clearStorageLoop(*_type.baseType()); m_context << Instruction::POP; } solAssert(m_context.stackHeight() == stackHeightStart - 2, ""); } void ArrayUtils::clearDynamicArray(ArrayType const& _type) const { solAssert(_type.location() == DataLocation::Storage, ""); solAssert(_type.isDynamicallySized(), ""); // fetch length retrieveLength(_type); // set length to zero m_context << u256(0) << Instruction::DUP3 << Instruction::SSTORE; // Special case: short byte arrays are stored togeher with their length eth::AssemblyItem endTag = m_context.newTag(); if (_type.isByteArray()) { // stack: ref old_length m_context << Instruction::DUP1 << u256(31) << Instruction::LT; eth::AssemblyItem longByteArray = m_context.appendConditionalJump(); m_context << Instruction::POP; m_context.appendJumpTo(endTag); m_context.adjustStackOffset(1); // needed because of jump m_context << longByteArray; } // stack: ref old_length convertLengthToSize(_type); // compute data positions m_context << Instruction::SWAP1; CompilerUtils(m_context).computeHashStatic(); // stack: len data_pos m_context << Instruction::SWAP1 << Instruction::DUP2 << Instruction::ADD << Instruction::SWAP1; // stack: data_pos_end data_pos if (_type.isByteArray() || _type.baseType()->storageBytes() < 32) clearStorageLoop(IntegerType(256)); else clearStorageLoop(*_type.baseType()); // cleanup m_context << endTag; m_context << Instruction::POP; } void ArrayUtils::resizeDynamicArray(ArrayType const& _type) const { solAssert(_type.location() == DataLocation::Storage, ""); solAssert(_type.isDynamicallySized(), ""); if (!_type.isByteArray() && _type.baseType()->storageBytes() < 32) solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type."); unsigned stackHeightStart = m_context.stackHeight(); eth::AssemblyItem resizeEnd = m_context.newTag(); // stack: ref new_length // fetch old length retrieveLength(_type, 1); // stack: ref new_length old_length solAssert(m_context.stackHeight() - stackHeightStart == 3 - 2, "2"); // Special case for short byte arrays, they are stored together with their length if (_type.isByteArray()) { eth::AssemblyItem regularPath = m_context.newTag(); // We start by a large case-distinction about the old and new length of the byte array. m_context << Instruction::DUP3 << Instruction::SLOAD; // stack: ref new_length current_length ref_value solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3"); m_context << Instruction::DUP2 << u256(31) << Instruction::LT; eth::AssemblyItem currentIsLong = m_context.appendConditionalJump(); m_context << Instruction::DUP3 << u256(31) << Instruction::LT; eth::AssemblyItem newIsLong = m_context.appendConditionalJump(); // Here: short -> short // Compute 1 << (256 - 8 * new_size) eth::AssemblyItem shortToShort = m_context.newTag(); m_context << shortToShort; m_context << Instruction::DUP3 << u256(8) << Instruction::MUL; m_context << u256(0x100) << Instruction::SUB; m_context << u256(2) << Instruction::EXP; // Divide and multiply by that value, clearing bits. m_context << Instruction::DUP1 << Instruction::SWAP2; m_context << Instruction::DIV << Instruction::MUL; // Insert 2*length. m_context << Instruction::DUP3 << Instruction::DUP1 << Instruction::ADD; m_context << Instruction::OR; // Store. m_context << Instruction::DUP4 << Instruction::SSTORE; solAssert(m_context.stackHeight() - stackHeightStart == 3 - 2, "3"); m_context.appendJumpTo(resizeEnd); m_context.adjustStackOffset(1); // we have to do that because of the jumps // Here: short -> long m_context << newIsLong; // stack: ref new_length current_length ref_value solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3"); // Zero out lower-order byte. m_context << u256(0xff) << Instruction::NOT << Instruction::AND; // Store at data location. m_context << Instruction::DUP4; CompilerUtils(m_context).computeHashStatic(); m_context << Instruction::SSTORE; // stack: ref new_length current_length // Store new length: Compule 2*length + 1 and store it. m_context << Instruction::DUP2 << Instruction::DUP1 << Instruction::ADD; m_context << u256(1) << Instruction::ADD; // stack: ref new_length current_length 2*new_length+1 m_context << Instruction::DUP4 << Instruction::SSTORE; solAssert(m_context.stackHeight() - stackHeightStart == 3 - 2, "3"); m_context.appendJumpTo(resizeEnd); m_context.adjustStackOffset(1); // we have to do that because of the jumps m_context << currentIsLong; m_context << Instruction::DUP3 << u256(31) << Instruction::LT; m_context.appendConditionalJumpTo(regularPath); // Here: long -> short // Read the first word of the data and store it on the stack. Clear the data location and // then jump to the short -> short case. // stack: ref new_length current_length ref_value solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3"); m_context << Instruction::POP << Instruction::DUP3; CompilerUtils(m_context).computeHashStatic(); m_context << Instruction::DUP1 << Instruction::SLOAD << Instruction::SWAP1; // stack: ref new_length current_length first_word data_location m_context << Instruction::DUP3; convertLengthToSize(_type); m_context << Instruction::DUP2 << Instruction::ADD << Instruction::SWAP1; // stack: ref new_length current_length first_word data_location_end data_location clearStorageLoop(IntegerType(256)); m_context << Instruction::POP; // stack: ref new_length current_length first_word solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3"); m_context.appendJumpTo(shortToShort); m_context << regularPath; // stack: ref new_length current_length ref_value m_context << Instruction::POP; } // Change of length for a regular array (i.e. length at location, data at sha3(location)). // stack: ref new_length old_length // store new length m_context << Instruction::DUP2; if (_type.isByteArray()) // For a "long" byte array, store length as 2*length+1 m_context << Instruction::DUP1 << Instruction::ADD << u256(1) << Instruction::ADD; m_context<< Instruction::DUP4 << Instruction::SSTORE; // skip if size is not reduced m_context << Instruction::DUP2 << Instruction::DUP2 << Instruction::ISZERO << Instruction::GT; m_context.appendConditionalJumpTo(resizeEnd); // size reduced, clear the end of the array // stack: ref new_length old_length convertLengthToSize(_type); m_context << Instruction::DUP2; convertLengthToSize(_type); // stack: ref new_length old_size new_size // compute data positions m_context << Instruction::DUP4; CompilerUtils(m_context).computeHashStatic(); // stack: ref new_length old_size new_size data_pos m_context << Instruction::SWAP2 << Instruction::DUP3 << Instruction::ADD; // stack: ref new_length data_pos new_size delete_end m_context << Instruction::SWAP2 << Instruction::ADD; // stack: ref new_length delete_end delete_start if (_type.isByteArray() || _type.baseType()->storageBytes() < 32) clearStorageLoop(IntegerType(256)); else clearStorageLoop(*_type.baseType()); m_context << resizeEnd; // cleanup m_context << Instruction::POP << Instruction::POP << Instruction::POP; solAssert(m_context.stackHeight() == stackHeightStart - 2, ""); } void ArrayUtils::clearStorageLoop(Type const& _type) const { unsigned stackHeightStart = m_context.stackHeight(); if (_type.category() == Type::Category::Mapping) { m_context << Instruction::POP; return; } // stack: end_pos pos // jump to and return from the loop to allow for duplicate code removal eth::AssemblyItem returnTag = m_context.pushNewTag(); m_context << Instruction::SWAP2 << Instruction::SWAP1; // stack: end_pos pos eth::AssemblyItem loopStart = m_context.appendJumpToNew(); m_context << loopStart; // check for loop condition m_context << Instruction::DUP1 << Instruction::DUP3 << Instruction::GT << Instruction::ISZERO; eth::AssemblyItem zeroLoopEnd = m_context.newTag(); m_context.appendConditionalJumpTo(zeroLoopEnd); // delete m_context << u256(0); StorageItem(m_context, _type).setToZero(SourceLocation(), false); m_context << Instruction::POP; // increment m_context << _type.storageSize() << Instruction::ADD; m_context.appendJumpTo(loopStart); // cleanup m_context << zeroLoopEnd; m_context << Instruction::POP << Instruction::SWAP1; // "return" m_context << Instruction::JUMP; m_context << returnTag; solAssert(m_context.stackHeight() == stackHeightStart - 1, ""); } void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType, bool _pad) const { if (_arrayType.location() == DataLocation::Storage) { if (_arrayType.baseType()->storageSize() <= 1) { unsigned baseBytes = _arrayType.baseType()->storageBytes(); if (baseBytes == 0) m_context << Instruction::POP << u256(1); else if (baseBytes <= 16) { unsigned itemsPerSlot = 32 / baseBytes; m_context << u256(itemsPerSlot - 1) << Instruction::ADD << u256(itemsPerSlot) << Instruction::SWAP1 << Instruction::DIV; } } else m_context << _arrayType.baseType()->storageSize() << Instruction::MUL; } else { if (!_arrayType.isByteArray()) { if (_arrayType.location() == DataLocation::Memory) m_context << _arrayType.baseType()->memoryHeadSize(); else m_context << _arrayType.baseType()->calldataEncodedSize(); m_context << Instruction::MUL; } else if (_pad) m_context << u256(31) << Instruction::ADD << u256(32) << Instruction::DUP1 << Instruction::SWAP2 << Instruction::DIV << Instruction::MUL; } } void ArrayUtils::retrieveLength(ArrayType const& _arrayType, unsigned _stackDepth) const { if (!_arrayType.isDynamicallySized()) m_context << _arrayType.length(); else { m_context << dupInstruction(1 + _stackDepth); switch (_arrayType.location()) { case DataLocation::CallData: // length is stored on the stack break; case DataLocation::Memory: m_context << Instruction::MLOAD; break; case DataLocation::Storage: m_context << Instruction::SLOAD; if (_arrayType.isByteArray()) { // Retrieve length both for in-place strings and off-place strings: // Computes (x & (0x100 * (ISZERO (x & 1)) - 1)) / 2 // i.e. for short strings (x & 1 == 0) it does (x & 0xff) / 2 and for long strings it // computes (x & (-1)) / 2, which is equivalent to just x / 2. m_context << u256(1) << Instruction::DUP2 << u256(1) << Instruction::AND; m_context << Instruction::ISZERO << u256(0x100) << Instruction::MUL; m_context << Instruction::SUB << Instruction::AND; m_context << u256(2) << Instruction::SWAP1 << Instruction::DIV; } break; } } } void ArrayUtils::accessIndex(ArrayType const& _arrayType, bool _doBoundsCheck) const { /// Stack: reference [length] index DataLocation location = _arrayType.location(); if (_doBoundsCheck) { // retrieve length ArrayUtils::retrieveLength(_arrayType, 1); // Stack: ref [length] index length // check out-of-bounds access m_context << Instruction::DUP2 << Instruction::LT << Instruction::ISZERO; // out-of-bounds access throws exception m_context.appendConditionalJumpTo(m_context.errorTag()); } if (location == DataLocation::CallData && _arrayType.isDynamicallySized()) // remove length if present m_context << Instruction::SWAP1 << Instruction::POP; // stack: m_context << Instruction::SWAP1; // stack: switch (location) { case DataLocation::Memory: if (_arrayType.isDynamicallySized()) m_context << u256(32) << Instruction::ADD; // fall-through case DataLocation::CallData: if (!_arrayType.isByteArray()) { m_context << Instruction::SWAP1; if (location == DataLocation::CallData) m_context << _arrayType.baseType()->calldataEncodedSize(); else m_context << u256(_arrayType.memoryHeadSize()); m_context << Instruction::MUL; } m_context << Instruction::ADD; break; case DataLocation::Storage: { eth::AssemblyItem endTag = m_context.newTag(); if (_arrayType.isByteArray()) { // Special case of short byte arrays. m_context << Instruction::SWAP1; m_context << Instruction::DUP2 << Instruction::SLOAD; m_context << u256(1) << Instruction::AND << Instruction::ISZERO; // No action needed for short byte arrays. m_context.appendConditionalJumpTo(endTag); m_context << Instruction::SWAP1; } if (_arrayType.isDynamicallySized()) CompilerUtils(m_context).computeHashStatic(); m_context << Instruction::SWAP1; if (_arrayType.baseType()->storageBytes() <= 16) { // stack: // goal: // = <(index % itemsPerSlot) * byteSize> unsigned byteSize = _arrayType.baseType()->storageBytes(); solAssert(byteSize != 0, ""); unsigned itemsPerSlot = 32 / byteSize; m_context << u256(itemsPerSlot) << Instruction::SWAP2; // stack: itemsPerSlot index data_ref m_context << Instruction::DUP3 << Instruction::DUP3 << Instruction::DIV << Instruction::ADD // stack: itemsPerSlot index (data_ref + index / itemsPerSlot) << Instruction::SWAP2 << Instruction::SWAP1 << Instruction::MOD; if (byteSize != 1) m_context << u256(byteSize) << Instruction::MUL; } else { if (_arrayType.baseType()->storageSize() != 1) m_context << _arrayType.baseType()->storageSize() << Instruction::MUL; m_context << Instruction::ADD << u256(0); } m_context << endTag; break; } default: solAssert(false, ""); } } void ArrayUtils::incrementByteOffset(unsigned _byteSize, unsigned _byteOffsetPosition, unsigned _storageOffsetPosition) const { solAssert(_byteSize < 32, ""); solAssert(_byteSize != 0, ""); // We do the following, but avoiding jumps: // byteOffset += byteSize // if (byteOffset + byteSize > 32) // { // storageOffset++; // byteOffset = 0; // } if (_byteOffsetPosition > 1) m_context << swapInstruction(_byteOffsetPosition - 1); m_context << u256(_byteSize) << Instruction::ADD; if (_byteOffsetPosition > 1) m_context << swapInstruction(_byteOffsetPosition - 1); // compute, X := (byteOffset + byteSize - 1) / 32, should be 1 iff byteOffset + bytesize > 32 m_context << u256(32) << dupInstruction(1 + _byteOffsetPosition) << u256(_byteSize - 1) << Instruction::ADD << Instruction::DIV; // increment storage offset if X == 1 (just add X to it) // stack: X m_context << swapInstruction(_storageOffsetPosition) << dupInstruction(_storageOffsetPosition + 1) << Instruction::ADD << swapInstruction(_storageOffsetPosition); // stack: X // set source_byte_offset to zero if X == 1 (using source_byte_offset *= 1 - X) m_context << u256(1) << Instruction::SUB; // stack: 1 - X if (_byteOffsetPosition == 1) m_context << Instruction::MUL; else m_context << dupInstruction(_byteOffsetPosition + 1) << Instruction::MUL << swapInstruction(_byteOffsetPosition) << Instruction::POP; }