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Diffstat (limited to 'libsolidity/ArrayUtils.cpp')
| -rw-r--r-- | libsolidity/ArrayUtils.cpp | 786 |
1 files changed, 786 insertions, 0 deletions
diff --git a/libsolidity/ArrayUtils.cpp b/libsolidity/ArrayUtils.cpp new file mode 100644 index 00000000..48ee5a05 --- /dev/null +++ b/libsolidity/ArrayUtils.cpp @@ -0,0 +1,786 @@ +/* + 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 +{ + // 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.getBaseType()); + Type const* sourceBaseType = _sourceType.isByteArray() ? &uint256 : &(*_sourceType.getBaseType()); + + // 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->getStorageBytes() <= 16; + bool haveByteOffsetTarget = !directCopy && targetBaseType->getStorageBytes() <= 16; + unsigned byteOffsetSize = (haveByteOffsetSource ? 1 : 0) + (haveByteOffsetTarget ? 1 : 0); + + // stack: source_ref [source_length] target_ref + // store target_ref + for (unsigned i = _sourceType.getSizeOnStack(); i > 0; --i) + m_context << eth::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 << eth::Instruction::SWAP1 << u256(0x20); + m_context << eth::Instruction::ADD << eth::Instruction::SWAP1; + } + + // stack: target_ref source_ref source_length + m_context << eth::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 + m_context << eth::Instruction::DUP3 << eth::Instruction::DUP3 << eth::Instruction::SSTORE; + if (sourceBaseType->getCategory() == Type::Category::Mapping) + { + solAssert(targetBaseType->getCategory() == Type::Category::Mapping, ""); + solAssert(_sourceType.location() == DataLocation::Storage, ""); + // nothing to copy + m_context + << eth::Instruction::POP << eth::Instruction::POP + << eth::Instruction::POP << eth::Instruction::POP; + return; + } + // compute hashes (data positions) + m_context << eth::Instruction::SWAP1; + if (_targetType.isDynamicallySized()) + CompilerUtils(m_context).computeHashStatic(); + // stack: target_ref source_ref source_length target_length target_data_pos + m_context << eth::Instruction::SWAP1; + convertLengthToSize(_targetType); + m_context << eth::Instruction::DUP2 << eth::Instruction::ADD; + // stack: target_ref source_ref source_length target_data_pos target_data_end + m_context << eth::Instruction::SWAP3; + // stack: target_ref target_data_end source_length target_data_pos source_ref + // skip copying if source length is zero + m_context << eth::Instruction::DUP3 << eth::Instruction::ISZERO; + eth::AssemblyItem copyLoopEndWithoutByteOffset = m_context.newTag(); + 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 << eth::Instruction::SWAP2; + convertLengthToSize(_sourceType); + m_context << eth::Instruction::DUP3 << eth::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 + << eth::dupInstruction(3 + byteOffsetSize) << eth::dupInstruction(2 + byteOffsetSize) + << eth::Instruction::GT << eth::Instruction::ISZERO; + eth::AssemblyItem copyLoopEnd = m_context.newTag(); + m_context.appendConditionalJumpTo(copyLoopEnd); + // stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] + // copy + if (sourceBaseType->getCategory() == Type::Category::Array) + { + solAssert(byteOffsetSize == 0, "Byte offset for array as base type."); + auto const& sourceBaseArrayType = dynamic_cast<ArrayType const&>(*sourceBaseType); + m_context << eth::Instruction::DUP3; + if (sourceBaseArrayType.location() == DataLocation::Memory) + m_context << eth::Instruction::MLOAD; + m_context << eth::Instruction::DUP3; + copyArrayToStorage(dynamic_cast<ArrayType const&>(*targetBaseType), sourceBaseArrayType); + m_context << eth::Instruction::POP; + } + else if (directCopy) + { + solAssert(byteOffsetSize == 0, "Byte offset for direct copy."); + m_context + << eth::Instruction::DUP3 << eth::Instruction::SLOAD + << eth::Instruction::DUP3 << eth::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 << eth::dupInstruction(3 + byteOffsetSize); + if (_sourceType.location() == DataLocation::Storage) + { + if (haveByteOffsetSource) + m_context << eth::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] <source_value>... + solAssert( + 2 + byteOffsetSize + sourceBaseType->getSizeOnStack() <= 16, + "Stack too deep, try removing local variables." + ); + // fetch target storage reference + m_context << eth::dupInstruction(2 + byteOffsetSize + sourceBaseType->getSizeOnStack()); + if (haveByteOffsetTarget) + m_context << eth::dupInstruction(1 + byteOffsetSize + sourceBaseType->getSizeOnStack()); + 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->getStorageBytes(), 1, haveByteOffsetTarget ? 5 : 4); + else + { + m_context << eth::swapInstruction(2 + byteOffsetSize); + if (sourceIsStorage) + m_context << sourceBaseType->getStorageSize(); + else if (_sourceType.location() == DataLocation::Memory) + m_context << sourceBaseType->memoryHeadSize(); + else + m_context << sourceBaseType->getCalldataEncodedSize(true); + m_context + << eth::Instruction::ADD + << eth::swapInstruction(2 + byteOffsetSize); + } + // increment target + if (haveByteOffsetTarget) + incrementByteOffset(targetBaseType->getStorageBytes(), byteOffsetSize, byteOffsetSize + 2); + else + m_context + << eth::swapInstruction(1 + byteOffsetSize) + << targetBaseType->getStorageSize() + << eth::Instruction::ADD + << eth::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 << eth::dupInstruction(byteOffsetSize) << eth::Instruction::ISZERO; + eth::AssemblyItem copyCleanupLoopEnd = m_context.appendConditionalJump(); + m_context << eth::dupInstruction(2 + byteOffsetSize) << eth::dupInstruction(1 + byteOffsetSize); + StorageItem(m_context, *targetBaseType).setToZero(SourceLocation(), true); + incrementByteOffset(targetBaseType->getStorageBytes(), byteOffsetSize, byteOffsetSize + 2); + m_context.appendJumpTo(copyLoopEnd); + + m_context << copyCleanupLoopEnd; + m_context << eth::Instruction::POP; // might pop the source, but then target is popped next + } + if (haveByteOffsetSource) + m_context << eth::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 << eth::Instruction::POP << eth::Instruction::SWAP1 << eth::Instruction::POP; + // stack: target_ref target_data_end target_data_pos_updated + clearStorageLoop(*targetBaseType); + m_context << eth::Instruction::POP; +} + +void ArrayUtils::copyArrayToMemory(const ArrayType& _sourceType, bool _padToWordBoundaries) const +{ + solAssert( + _sourceType.getBaseType()->getCalldataEncodedSize() > 0, + "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.getBaseType()->getCalldataEncodedSize(); + + if (_sourceType.location() == DataLocation::CallData) + { + if (!_sourceType.isDynamicallySized()) + m_context << _sourceType.getLength(); + if (baseSize > 1) + m_context << u256(baseSize) << eth::Instruction::MUL; + // stack: target source_offset source_len + m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3 << eth::Instruction::DUP5; + // stack: target source_offset source_len source_len source_offset target + m_context << eth::Instruction::CALLDATACOPY; + m_context << eth::Instruction::DUP3 << eth::Instruction::ADD; + m_context << eth::Instruction::SWAP2 << eth::Instruction::POP << eth::Instruction::POP; + } + else if (_sourceType.location() == DataLocation::Memory) + { + retrieveLength(_sourceType); + // stack: target source length + if (!_sourceType.getBaseType()->isValueType()) + { + // copy using a loop + m_context << u256(0) << eth::Instruction::SWAP3; + // stack: counter source length target + auto repeat = m_context.newTag(); + m_context << repeat; + m_context << eth::Instruction::DUP2 << eth::Instruction::DUP5; + m_context << eth::Instruction::LT << eth::Instruction::ISZERO; + auto loopEnd = m_context.appendConditionalJump(); + m_context << eth::Instruction::DUP3 << eth::Instruction::DUP5; + accessIndex(_sourceType, false); + MemoryItem(m_context, *_sourceType.getBaseType(), true).retrieveValue(SourceLocation(), true); + if (auto baseArray = dynamic_cast<ArrayType const*>(_sourceType.getBaseType().get())) + copyArrayToMemory(*baseArray, _padToWordBoundaries); + else + utils.storeInMemoryDynamic(*_sourceType.getBaseType()); + m_context << eth::Instruction::SWAP3 << u256(1) << eth::Instruction::ADD; + m_context << eth::Instruction::SWAP3; + m_context.appendJumpTo(repeat); + m_context << loopEnd; + m_context << eth::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 << eth::Instruction::SWAP1 << u256(32) << eth::Instruction::ADD; + m_context << eth::Instruction::SWAP1; + } + // convert length to size + if (baseSize > 1) + m_context << u256(baseSize) << eth::Instruction::MUL; + // stack: <target> <source> <size> + //@TODO do not use ::CALL if less than 32 bytes? + m_context << eth::Instruction::DUP1 << eth::Instruction::DUP4 << eth::Instruction::DUP4; + utils.memoryCopy(); + + m_context << eth::Instruction::SWAP1 << eth::Instruction::POP; + // stack: <target> <size> + + bool paddingNeeded = false; + if (_sourceType.isDynamicallySized()) + paddingNeeded = _padToWordBoundaries && ((baseSize % 32) != 0); + else + paddingNeeded = _padToWordBoundaries && (((_sourceType.getLength() * baseSize) % 32) != 0); + if (paddingNeeded) + { + // stack: <target> <size> + m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD; + // stack: <length> <target + size> + m_context << eth::Instruction::SWAP1 << u256(31) << eth::Instruction::AND; + // stack: <target + size> <remainder = size % 32> + eth::AssemblyItem skip = m_context.newTag(); + if (_sourceType.isDynamicallySized()) + { + m_context << eth::Instruction::DUP1 << eth::Instruction::ISZERO; + m_context.appendConditionalJumpTo(skip); + } + // round off, load from there. + // stack <target + size> <remainder = size % 32> + m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3; + m_context << eth::Instruction::SUB; + // stack: target+size remainder <target + size - remainder> + m_context << eth::Instruction::DUP1 << eth::Instruction::MLOAD; + // Now we AND it with ~(2**(8 * (32 - remainder)) - 1) + m_context << u256(1); + m_context << eth::Instruction::DUP4 << u256(32) << eth::Instruction::SUB; + // stack: ...<v> 1 <32 - remainder> + m_context << u256(0x100) << eth::Instruction::EXP << eth::Instruction::SUB; + m_context << eth::Instruction::NOT << eth::Instruction::AND; + // stack: target+size remainder target+size-remainder <v & ...> + m_context << eth::Instruction::DUP2 << eth::Instruction::MSTORE; + // stack: target+size remainder target+size-remainder + m_context << u256(32) << eth::Instruction::ADD; + // stack: target+size remainder <new_padded_end> + m_context << eth::Instruction::SWAP2 << eth::Instruction::POP; + + if (_sourceType.isDynamicallySized()) + m_context << skip.tag(); + // stack <target + "size"> <remainder = size % 32> + m_context << eth::Instruction::POP; + } + else + // stack: <target> <size> + m_context << eth::Instruction::ADD; + } + else + { + solAssert(_sourceType.location() == DataLocation::Storage, ""); + unsigned storageBytes = _sourceType.getBaseType()->getStorageBytes(); + u256 storageSize = _sourceType.getBaseType()->getStorageSize(); + 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 << eth::Instruction::DUP1 << eth::Instruction::ISZERO; + eth::AssemblyItem loopEnd = m_context.newTag(); + m_context.appendConditionalJumpTo(loopEnd); + // compute memory end offset + if (baseSize > 1) + // convert length to memory size + m_context << u256(baseSize) << eth::Instruction::MUL; + m_context << eth::Instruction::DUP3 << eth::Instruction::ADD << eth::Instruction::SWAP2; + if (_sourceType.isDynamicallySized()) + { + // actual array data is stored at SHA3(storage_offset) + m_context << eth::Instruction::SWAP1; + utils.computeHashStatic(); + m_context << eth::Instruction::SWAP1; + } + + // stack here: memory_end_offset storage_data_offset memory_offset + bool haveByteOffset = !_sourceType.isByteArray() && storageBytes <= 16; + if (haveByteOffset) + m_context << u256(0) << eth::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 << eth::Instruction::DUP2 << eth::Instruction::SLOAD; + m_context << eth::Instruction::DUP2 << eth::Instruction::MSTORE; + // increment storage_data_offset by 1 + m_context << eth::Instruction::SWAP1 << u256(1) << eth::Instruction::ADD; + // increment memory offset by 32 + m_context << eth::Instruction::SWAP1 << u256(32) << eth::Instruction::ADD; + } + else + { + // stack here: memory_end_offset storage_data_offset [storage_byte_offset] memory_offset + if (haveByteOffset) + m_context << eth::Instruction::DUP3 << eth::Instruction::DUP3; + else + m_context << eth::Instruction::DUP2 << u256(0); + StorageItem(m_context, *_sourceType.getBaseType()).retrieveValue(SourceLocation(), true); + if (auto baseArray = dynamic_cast<ArrayType const*>(_sourceType.getBaseType().get())) + copyArrayToMemory(*baseArray, _padToWordBoundaries); + else + utils.storeInMemoryDynamic(*_sourceType.getBaseType()); + // increment storage_data_offset and byte offset + if (haveByteOffset) + incrementByteOffset(storageBytes, 2, 3); + else + { + m_context << eth::Instruction::SWAP1; + m_context << storageSize << eth::Instruction::ADD; + m_context << eth::Instruction::SWAP1; + } + } + // check for loop condition + m_context << eth::Instruction::DUP1 << eth::dupInstruction(haveByteOffset ? 5 : 4); + m_context << eth::Instruction::GT; + m_context.appendConditionalJumpTo(loopStart); + // stack here: memory_end_offset storage_data_offset [storage_byte_offset] memory_offset + if (haveByteOffset) + m_context << eth::Instruction::SWAP1 << eth::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 << eth::Instruction::DUP3 << eth::Instruction::SWAP1 << eth::Instruction::SUB; + m_context << u256(31) << eth::Instruction::AND; + m_context << eth::Instruction::DUP3 << eth::Instruction::ADD; + m_context << eth::Instruction::SWAP2; + } + m_context << loopEnd << eth::Instruction::POP << eth::Instruction::POP; + } +} + +void ArrayUtils::clearArray(ArrayType const& _type) const +{ + unsigned stackHeightStart = m_context.getStackHeight(); + solAssert(_type.location() == DataLocation::Storage, ""); + if (_type.getBaseType()->getStorageBytes() < 32) + { + solAssert(_type.getBaseType()->isValueType(), "Invalid storage size for non-value type."); + solAssert(_type.getBaseType()->getStorageSize() <= 1, "Invalid storage size for type."); + } + if (_type.getBaseType()->isValueType()) + solAssert(_type.getBaseType()->getStorageSize() <= 1, "Invalid size for value type."); + + m_context << eth::Instruction::POP; // remove byte offset + if (_type.isDynamicallySized()) + clearDynamicArray(_type); + else if (_type.getLength() == 0 || _type.getBaseType()->getCategory() == Type::Category::Mapping) + m_context << eth::Instruction::POP; + else if (_type.getBaseType()->isValueType() && _type.getStorageSize() <= 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.getStorageSize(); ++i) + m_context + << u256(0) << eth::Instruction::DUP2 << eth::Instruction::SSTORE + << u256(1) << eth::Instruction::ADD; + m_context << u256(0) << eth::Instruction::SWAP1 << eth::Instruction::SSTORE; + } + else if (!_type.getBaseType()->isValueType() && _type.getLength() <= 4) + { + // unroll loop for small arrays @todo choose a good value + solAssert(_type.getBaseType()->getStorageBytes() >= 32, "Invalid storage size."); + for (unsigned i = 1; i < _type.getLength(); ++i) + { + m_context << u256(0); + StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), false); + m_context + << eth::Instruction::POP + << u256(_type.getBaseType()->getStorageSize()) << eth::Instruction::ADD; + } + m_context << u256(0); + StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), true); + } + else + { + m_context << eth::Instruction::DUP1 << _type.getLength(); + convertLengthToSize(_type); + m_context << eth::Instruction::ADD << eth::Instruction::SWAP1; + if (_type.getBaseType()->getStorageBytes() < 32) + clearStorageLoop(IntegerType(256)); + else + clearStorageLoop(*_type.getBaseType()); + m_context << eth::Instruction::POP; + } + solAssert(m_context.getStackHeight() == stackHeightStart - 2, ""); +} + +void ArrayUtils::clearDynamicArray(ArrayType const& _type) const +{ + solAssert(_type.location() == DataLocation::Storage, ""); + solAssert(_type.isDynamicallySized(), ""); + + unsigned stackHeightStart = m_context.getStackHeight(); + // 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 + m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD + << eth::Instruction::SWAP1; + // stack: data_pos_end data_pos + if (_type.isByteArray() || _type.getBaseType()->getStorageBytes() < 32) + clearStorageLoop(IntegerType(256)); + else + clearStorageLoop(*_type.getBaseType()); + // cleanup + m_context << eth::Instruction::POP; + solAssert(m_context.getStackHeight() == stackHeightStart - 1, ""); +} + +void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const +{ + solAssert(_type.location() == DataLocation::Storage, ""); + solAssert(_type.isDynamicallySized(), ""); + if (!_type.isByteArray() && _type.getBaseType()->getStorageBytes() < 32) + solAssert(_type.getBaseType()->isValueType(), "Invalid storage size for non-value type."); + + unsigned stackHeightStart = m_context.getStackHeight(); + 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() || _type.getBaseType()->getStorageBytes() < 32) + clearStorageLoop(IntegerType(256)); + else + clearStorageLoop(*_type.getBaseType()); + + m_context << resizeEnd; + // cleanup + m_context << eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP; + solAssert(m_context.getStackHeight() == stackHeightStart - 2, ""); +} + +void ArrayUtils::clearStorageLoop(Type const& _type) const +{ + unsigned stackHeightStart = m_context.getStackHeight(); + if (_type.getCategory() == Type::Category::Mapping) + { + m_context << eth::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 << eth::Instruction::SWAP2 << eth::Instruction::SWAP1; + + // stack: <return tag> end_pos pos + eth::AssemblyItem loopStart = m_context.appendJumpToNew(); + 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 + m_context << u256(0); + StorageItem(m_context, _type).setToZero(SourceLocation(), false); + m_context << eth::Instruction::POP; + // increment + m_context << u256(1) << eth::Instruction::ADD; + m_context.appendJumpTo(loopStart); + // cleanup + m_context << zeroLoopEnd; + m_context << eth::Instruction::POP << eth::Instruction::SWAP1; + // "return" + m_context << eth::Instruction::JUMP; + + m_context << returnTag; + solAssert(m_context.getStackHeight() == stackHeightStart - 1, ""); +} + +void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType, bool _pad) const +{ + if (_arrayType.location() == DataLocation::Storage) + { + if (_arrayType.getBaseType()->getStorageSize() <= 1) + { + unsigned baseBytes = _arrayType.getBaseType()->getStorageBytes(); + if (baseBytes == 0) + m_context << eth::Instruction::POP << u256(1); + else if (baseBytes <= 16) + { + unsigned itemsPerSlot = 32 / baseBytes; + m_context + << u256(itemsPerSlot - 1) << eth::Instruction::ADD + << u256(itemsPerSlot) << eth::Instruction::SWAP1 << eth::Instruction::DIV; + } + } + else + m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL; + } + else + { + if (!_arrayType.isByteArray()) + { + if (_arrayType.location() == DataLocation::Memory) + m_context << _arrayType.getBaseType()->memoryHeadSize(); + else + m_context << _arrayType.getBaseType()->getCalldataEncodedSize(); + m_context << eth::Instruction::MUL; + } + else if (_pad) + m_context << u256(31) << eth::Instruction::ADD + << u256(32) << eth::Instruction::DUP1 + << eth::Instruction::SWAP2 << eth::Instruction::DIV << eth::Instruction::MUL; + } +} + +void ArrayUtils::retrieveLength(ArrayType const& _arrayType) const +{ + if (!_arrayType.isDynamicallySized()) + m_context << _arrayType.getLength(); + else + { + m_context << eth::Instruction::DUP1; + switch (_arrayType.location()) + { + case DataLocation::CallData: + // length is stored on the stack + break; + case DataLocation::Memory: + m_context << eth::Instruction::MLOAD; + break; + case DataLocation::Storage: + m_context << eth::Instruction::SLOAD; + break; + } + } +} + +void ArrayUtils::accessIndex(ArrayType const& _arrayType, bool _doBoundsCheck) const +{ + DataLocation location = _arrayType.location(); + eth::Instruction load = + location == DataLocation::Storage ? eth::Instruction::SLOAD : + location == DataLocation::Memory ? eth::Instruction::MLOAD : + eth::Instruction::CALLDATALOAD; + + if (_doBoundsCheck) + { + // retrieve length + if (!_arrayType.isDynamicallySized()) + m_context << _arrayType.getLength(); + else if (location == DataLocation::CallData) + // length is stored on the stack + m_context << eth::Instruction::SWAP1; + else + m_context << eth::Instruction::DUP2 << load; + // stack: <base_ref> <index> <length> + // check out-of-bounds access + m_context << eth::Instruction::DUP2 << eth::Instruction::LT << eth::Instruction::ISZERO; + // out-of-bounds access throws exception + m_context.appendConditionalJumpTo(m_context.errorTag()); + } + else if (location == DataLocation::CallData && _arrayType.isDynamicallySized()) + // remove length if present + m_context << eth::Instruction::SWAP1 << eth::Instruction::POP; + + // stack: <base_ref> <index> + m_context << eth::Instruction::SWAP1; + if (_arrayType.isDynamicallySized()) + { + if (location == DataLocation::Storage) + CompilerUtils(m_context).computeHashStatic(); + else if (location == DataLocation::Memory) + m_context << u256(32) << eth::Instruction::ADD; + } + // stack: <index> <data_ref> + switch (location) + { + case DataLocation::CallData: + case DataLocation::Memory: + if (!_arrayType.isByteArray()) + { + m_context << eth::Instruction::SWAP1; + if (location == DataLocation::CallData) + m_context << _arrayType.getBaseType()->getCalldataEncodedSize(); + else + m_context << u256(_arrayType.memoryHeadSize()); + m_context << eth::Instruction::MUL; + } + m_context << eth::Instruction::ADD; + break; + case DataLocation::Storage: + m_context << eth::Instruction::SWAP1; + if (_arrayType.getBaseType()->getStorageBytes() <= 16) + { + // stack: <data_ref> <index> + // goal: + // <ref> <byte_number> = <base_ref + index / itemsPerSlot> <(index % itemsPerSlot) * byteSize> + unsigned byteSize = _arrayType.getBaseType()->getStorageBytes(); + solAssert(byteSize != 0, ""); + unsigned itemsPerSlot = 32 / byteSize; + m_context << u256(itemsPerSlot) << eth::Instruction::SWAP2; + // stack: itemsPerSlot index data_ref + m_context + << eth::Instruction::DUP3 << eth::Instruction::DUP3 + << eth::Instruction::DIV << eth::Instruction::ADD + // stack: itemsPerSlot index (data_ref + index / itemsPerSlot) + << eth::Instruction::SWAP2 << eth::Instruction::SWAP1 + << eth::Instruction::MOD; + if (byteSize != 1) + m_context << u256(byteSize) << eth::Instruction::MUL; + } + else + { + if (_arrayType.getBaseType()->getStorageSize() != 1) + m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL; + m_context << eth::Instruction::ADD << u256(0); + } + break; + } +} + +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 << eth::swapInstruction(_byteOffsetPosition - 1); + m_context << u256(_byteSize) << eth::Instruction::ADD; + if (_byteOffsetPosition > 1) + m_context << eth::swapInstruction(_byteOffsetPosition - 1); + // compute, X := (byteOffset + byteSize - 1) / 32, should be 1 iff byteOffset + bytesize > 32 + m_context + << u256(32) << eth::dupInstruction(1 + _byteOffsetPosition) << u256(_byteSize - 1) + << eth::Instruction::ADD << eth::Instruction::DIV; + // increment storage offset if X == 1 (just add X to it) + // stack: X + m_context + << eth::swapInstruction(_storageOffsetPosition) << eth::dupInstruction(_storageOffsetPosition + 1) + << eth::Instruction::ADD << eth::swapInstruction(_storageOffsetPosition); + // stack: X + // set source_byte_offset to zero if X == 1 (using source_byte_offset *= 1 - X) + m_context << u256(1) << eth::Instruction::SUB; + // stack: 1 - X + if (_byteOffsetPosition == 1) + m_context << eth::Instruction::MUL; + else + m_context + << eth::dupInstruction(_byteOffsetPosition + 1) << eth::Instruction::MUL + << eth::swapInstruction(_byteOffsetPosition) << eth::Instruction::POP; +} |