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Merge pull request #9121 from ethereum/solYulIndexAccess

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[SolYul] Index access to fixed bytes and byte arrays.
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chriseth 2020-06-09 11:18:35 +02:00 committed by GitHub
commit 1319396bfb
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2 changed files with 38 additions and 2 deletions
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20
libsolidity/codegen/ir/IRGeneratorForStatements.cpp
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@ -1730,7 +1730,7 @@ void IRGeneratorForStatements::endVisit(IndexAccess const& _indexAccess)
setLValue(_indexAccess, IRLValue{ setLValue(_indexAccess, IRLValue{
*arrayType.baseType(), *arrayType.baseType(),
IRLValue::Memory{memAddress} IRLValue::Memory{memAddress, arrayType.isByteArray()}
}); });
break; break;
} }
@ -1763,7 +1763,23 @@ void IRGeneratorForStatements::endVisit(IndexAccess const& _indexAccess)
} }
} }
else if (baseType.category() == Type::Category::FixedBytes) else if (baseType.category() == Type::Category::FixedBytes)
solUnimplementedAssert(false, ""); {
auto const& fixedBytesType = dynamic_cast<FixedBytesType const&>(baseType);
solAssert(_indexAccess.indexExpression(), "Index expression expected.");
IRVariable index{m_context.newYulVariable(), *TypeProvider::uint256()};
define(index, *_indexAccess.indexExpression());
m_code << Whiskers(R"(
if iszero(lt(<index>, <length>)) { invalid() }
let <result> := <shl248>(byte(<index>, <array>))
)")
("index", index.name())
("length", to_string(fixedBytesType.numBytes()))
("array", IRVariable(_indexAccess.baseExpression()).name())
("shl248", m_utils.shiftLeftFunction(256 - 8))
("result", IRVariable(_indexAccess).name())
.render();
}
else if (baseType.category() == Type::Category::TypeType) else if (baseType.category() == Type::Category::TypeType)
{ {
solAssert(baseType.sizeOnStack() == 0, ""); solAssert(baseType.sizeOnStack() == 0, "");

20
test/libsolidity/semanticTests/array/index_access.sol Normal file
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@ -0,0 +1,20 @@
contract C {
function to_little_endian_64(uint64 value) public pure returns (bytes memory ret) {
ret = new bytes(8);
bytes8 bytesValue = bytes8(value);
// Byteswapping during copying to bytes.
ret[0] = bytesValue[7];
ret[1] = bytesValue[6];
ret[2] = bytesValue[5];
ret[3] = bytesValue[4];
ret[4] = bytesValue[3];
ret[5] = bytesValue[2];
ret[6] = bytesValue[1];
ret[7] = bytesValue[0];
}
}
// ====
// compileViaYul: also
// ----
// to_little_endian_64(uint64): 0 -> 0x20, 8, 0x00
// to_little_endian_64(uint64): 0x0102030405060708 -> 0x20, 8, 0x0807060504030201000000000000000000000000000000000000000000000000