mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
Shortening of dynamic arrays.
This commit is contained in:
Christian
@@ -164,134 +164,6 @@ void CompilerUtils::computeHashStatic(Type const& _type, bool _padToWordBoundari
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m_context << u256(length) << u256(0) << eth::Instruction::SHA3;
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}
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void CompilerUtils::copyByteArrayToStorage(
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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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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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switch (_sourceType.getLocation())
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{
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case ArrayType::Location::CallData:
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{
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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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m_context << u256(31) << eth::Instruction::ADD
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<< u256(32) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
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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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// store start offset
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m_context << eth::Instruction::DUP5;
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// stack now: source_offset source_len target_ref target_data_end target_data_ref 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::DUP3 << eth::Instruction::SSTORE
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// increment target_data_ref by 1
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<< eth::Instruction::SWAP1 << u256(1) << eth::Instruction::ADD
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// increment calldata_offset by 32
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<< eth::Instruction::SWAP1 << u256(32) << eth::Instruction::ADD
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// check for loop condition
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<< eth::Instruction::DUP1 << eth::Instruction::DUP6 << eth::Instruction::GT;
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m_context.appendConditionalJumpTo(copyLoopStart);
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m_context << 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();
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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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// 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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// fetch lengthes
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m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD << eth::Instruction::SWAP2
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<< eth::Instruction::DUP1 << eth::Instruction::SLOAD;
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// stack: target_ref target_len_bytes target_ref source_ref source_len_bytes
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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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CompilerUtils(m_context).computeHashStatic();
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m_context << eth::Instruction::SWAP1;
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CompilerUtils(m_context).computeHashStatic();
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// stack: target_ref target_len_bytes source_len_bytes target_data_pos source_data_pos
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// convert lengthes from bytes to storage slots
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m_context << u256(31) << u256(32) << eth::Instruction::DUP1 << eth::Instruction::DUP3
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<< eth::Instruction::DUP8 << eth::Instruction::ADD << eth::Instruction::DIV
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<< eth::Instruction::SWAP2
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<< eth::Instruction::DUP6 << eth::Instruction::ADD << eth::Instruction::DIV;
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// stack: target_ref target_len_bytes source_len_bytes target_data_pos source_data_pos target_len source_len
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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_bytes source_len_bytes target_data_pos source_data_pos target_len source_len 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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<< eth::Instruction::SLOAD
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<< eth::Instruction::DUP6 << eth::Instruction::DUP3 << eth::Instruction::ADD
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<< eth::Instruction::SSTORE;
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// increment
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m_context << u256(1) << 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_bytes source_len_bytes target_data_pos source_data_pos target_len source_len 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_bytes target_data_pos_updated target_data_pos source_data_pos target_len source_len
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// add length 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();
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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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unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries)
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{
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unsigned _encodedSize = _type.getCalldataEncodedSize();
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@@ -316,28 +188,6 @@ unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCallda
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return numBytes;
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}
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void CompilerUtils::clearByteArray(ArrayType const& _type) const
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{
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solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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solAssert(_type.isByteArray(), "Non byte arrays not yet implemented here.");
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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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// convert length from bytes to storage slots
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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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// 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
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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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clearStorageLoop();
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// cleanup
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m_context << eth::Instruction::POP;
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}
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unsigned CompilerUtils::prepareMemoryStore(Type const& _type, bool _padToWordBoundaries) const
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{
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@@ -356,25 +206,5 @@ unsigned CompilerUtils::prepareMemoryStore(Type const& _type, bool _padToWordBou
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return numBytes;
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}
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void CompilerUtils::clearStorageLoop() 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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// zero out
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m_context << u256(0) << eth::Instruction::DUP2 << eth::Instruction::SSTORE;
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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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}
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}
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