New ABI encoder.

author: chriseth <chris@ethereum.org> 2017-08-07 22:43:26 +0800
committer: chriseth <chris@ethereum.org> 2017-08-14 18:44:25 +0800
commit: 42fe8a2cb1530a557365d47878144c05687b859b (patch)
tree: 1de65fdcf1726af091fe661c9a3af3f1841b06ea /libsolidity/codegen/ABIFunctions.cpp
parent: bda410bb071e0d66f393aed3ee9f96d68a8fbb41 (diff)
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1 files changed, 1074 insertions, 0 deletions
diff --git a/libsolidity/codegen/ABIFunctions.cpp b/libsolidity/codegen/ABIFunctions.cpp
new file mode 100644
index 00000000..a2938ed7
--- /dev/null
+++ b/libsolidity/codegen/ABIFunctions.cpp
@@ -0,0 +1,1074 @@
+/*
+	This file is part of solidity.
+
+	solidity 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.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @author Christian <chris@ethereum.org>
+ * @date 2017
+ * Routines that generate JULIA code related to ABI encoding, decoding and type conversions.
+ */
+
+#include <libsolidity/codegen/ABIFunctions.h>
+
+#include <libdevcore/Whiskers.h>
+
+#include <libsolidity/ast/AST.h>
+
+using namespace std;
+using namespace dev;
+using namespace dev::solidity;
+
+ABIFunctions::~ABIFunctions()
+{
+	// This throws an exception and thus might cause immediate termination, but hey,
+	// it's a failed assertion anyway :-)
+	solAssert(m_requestedFunctions.empty(), "Forgot to call ``requestedFunctions()``.");
+}
+
+string ABIFunctions::tupleEncoder(
+	TypePointers const& _givenTypes,
+	TypePointers const& _targetTypes,
+	bool _encodeAsLibraryTypes
+)
+{
+	// stack: <$value0> <$value1> ... <$value(n-1)> <$headStart>
+
+	solAssert(!_givenTypes.empty(), "");
+	size_t const headSize_ = headSize(_targetTypes);
+
+	Whiskers encoder(R"(
+		{
+			let tail := add($headStart, <headSize>)
+			<encodeElements>
+			<deepestStackElement> := tail
+		}
+	)");
+	encoder("headSize", to_string(headSize_));
+	string encodeElements;
+	size_t headPos = 0;
+	size_t stackPos = 0;
+	for (size_t i = 0; i < _givenTypes.size(); ++i)
+	{
+		solAssert(_givenTypes[i], "");
+		solAssert(_targetTypes[i], "");
+		size_t sizeOnStack = _givenTypes[i]->sizeOnStack();
+		string valueNames = "";
+		for (size_t j = 0; j < sizeOnStack; j++)
+			valueNames += "$value" + to_string(stackPos++) + ", ";
+		bool dynamic = _targetTypes[i]->isDynamicallyEncoded();
+		Whiskers elementTempl(
+			dynamic ?
+			string(R"(
+				mstore(add($headStart, <pos>), sub(tail, $headStart))
+				tail := <abiEncode>(<values> tail)
+			)") :
+			string(R"(
+				<abiEncode>(<values> add($headStart, <pos>))
+			)")
+		);
+		elementTempl("values", valueNames);
+		elementTempl("pos", to_string(headPos));
+		elementTempl("abiEncode", abiEncodingFunction(*_givenTypes[i], *_targetTypes[i], _encodeAsLibraryTypes, false));
+		encodeElements += elementTempl.render();
+		headPos += dynamic ? 0x20 : _targetTypes[i]->calldataEncodedSize();
+	}
+	solAssert(headPos == headSize_, "");
+	encoder("encodeElements", encodeElements);
+	encoder("deepestStackElement", stackPos > 0 ? "$value0" : "$headStart");
+
+	return encoder.render();
+}
+
+string ABIFunctions::requestedFunctions()
+{
+	string result;
+	for (auto const& f: m_requestedFunctions)
+		result += f.second;
+	m_requestedFunctions.clear();
+	return result;
+}
+
+string ABIFunctions::cleanupFunction(Type const& _type, bool _revertOnFailure)
+{
+	string functionName = string("cleanup_") + (_revertOnFailure ? "revert_" : "assert_") + _type.identifier();
+	return createFunction(functionName, [&]() {
+		Whiskers templ(R"(
+			function <functionName>(value) -> cleaned {
+				<body>
+			}
+		)");
+		templ("functionName", functionName);
+		switch (_type.category())
+		{
+		case Type::Category::Integer:
+		{
+			IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
+			if (type.numBits() == 256)
+				templ("body", "cleaned := value");
+			else if (type.isSigned())
+				templ("body", "cleaned := signextend(" + to_string(type.numBits() / 8 - 1) + ", value)");
+			else
+				templ("body", "cleaned := and(value, " + toCompactHexWithPrefix((u256(1) << type.numBits()) - 1) + ")");
+			break;
+		}
+		case Type::Category::RationalNumber:
+			templ("body", "cleaned := value");
+			break;
+		case Type::Category::Bool:
+			templ("body", "cleaned := iszero(iszero(value))");
+			break;
+		case Type::Category::FixedPoint:
+			solUnimplemented("Fixed point types not implemented.");
+			break;
+		case Type::Category::Array:
+			solAssert(false, "Array cleanup requested.");
+			break;
+		case Type::Category::Struct:
+			solAssert(false, "Struct cleanup requested.");
+			break;
+		case Type::Category::FixedBytes:
+		{
+			FixedBytesType const& type = dynamic_cast<FixedBytesType const&>(_type);
+			if (type.numBytes() == 32)
+				templ("body", "cleaned := value");
+			else if (type.numBytes() == 0)
+				templ("body", "cleaned := 0");
+			else
+			{
+				size_t numBits = type.numBytes() * 8;
+				u256 mask = ((u256(1) << numBits) - 1) << (256 - numBits);
+				templ("body", "cleaned := and(value, " + toCompactHexWithPrefix(mask) + ")");
+			}
+			break;
+		}
+		case Type::Category::Contract:
+			templ("body", "cleaned := " + cleanupFunction(IntegerType(0, IntegerType::Modifier::Address)) + "(value)");
+			break;
+		case Type::Category::Enum:
+		{
+			size_t members = dynamic_cast<EnumType const&>(_type).numberOfMembers();
+			solAssert(members > 0, "empty enum should have caused a parser error.");
+			Whiskers w("switch lt(value, <members>) case 0 { <failure> } cleaned := value");
+			w("members", to_string(members));
+			if (_revertOnFailure)
+				w("failure", "revert(0, 0)");
+			else
+				w("failure", "invalid()");
+			templ("body", w.render());
+			break;
+		}
+		default:
+			solAssert(false, "Cleanup of type " + _type.identifier() + " requested.");
+		}
+
+		return templ.render();
+	});
+}
+
+string ABIFunctions::conversionFunction(Type const& _from, Type const& _to)
+{
+	string functionName =
+		"convert_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier();
+	return createFunction(functionName, [&]() {
+		Whiskers templ(R"(
+			function <functionName>(value) -> converted {
+				<body>
+			}
+		)");
+		templ("functionName", functionName);
+		string body;
+		auto toCategory = _to.category();
+		auto fromCategory = _from.category();
+		switch (fromCategory)
+		{
+		case Type::Category::Integer:
+		case Type::Category::RationalNumber:
+		case Type::Category::Contract:
+		{
+			if (RationalNumberType const* rational = dynamic_cast<RationalNumberType const*>(&_from))
+				solUnimplementedAssert(!rational->isFractional(), "Not yet implemented - FixedPointType.");
+			if (toCategory == Type::Category::FixedBytes)
+			{
+				solAssert(
+					fromCategory == Type::Category::Integer || fromCategory == Type::Category::RationalNumber,
+					"Invalid conversion to FixedBytesType requested."
+				);
+				FixedBytesType const& toBytesType = dynamic_cast<FixedBytesType const&>(_to);
+				body =
+					Whiskers("converted := <shiftLeft>(<clean>(value))")
+						("shiftLeft", shiftLeftFunction(256 - toBytesType.numBytes() * 8))
+						("clean", cleanupFunction(_from))
+						.render();
+			}
+			else if (toCategory == Type::Category::Enum)
+			{
+				solAssert(_from.mobileType(), "");
+				body =
+					Whiskers("converted := <cleanEnum>(<cleanInt>(value))")
+					("cleanEnum", cleanupFunction(_to, false))
+					// "mobileType()" returns integer type for rational
+					("cleanInt", cleanupFunction(*_from.mobileType()))
+					.render();
+			}
+			else if (toCategory == Type::Category::FixedPoint)
+			{
+				solUnimplemented("Not yet implemented - FixedPointType.");
+			}
+			else
+			{
+				solAssert(
+					toCategory == Type::Category::Integer ||
+					toCategory == Type::Category::Contract,
+				"");
+				IntegerType const addressType(0, IntegerType::Modifier::Address);
+				IntegerType const& to =
+					toCategory == Type::Category::Integer ?
+					dynamic_cast<IntegerType const&>(_to) :
+					addressType;
+
+				// Clean according to the "to" type, except if this is
+				// a widening conversion.
+				IntegerType const* cleanupType = &to;
+				if (fromCategory != Type::Category::RationalNumber)
+				{
+					IntegerType const& from =
+						fromCategory == Type::Category::Integer ?
+						dynamic_cast<IntegerType const&>(_from) :
+						addressType;
+					if (to.numBits() > from.numBits())
+						cleanupType = &from;
+				}
+				body =
+					Whiskers("converted := <cleanInt>(value)")
+					("cleanInt", cleanupFunction(*cleanupType))
+					.render();
+			}
+			break;
+		}
+		case Type::Category::Bool:
+		{
+			solAssert(_from == _to, "Invalid conversion for bool.");
+			body =
+				Whiskers("converted := <clean>(value)")
+				("clean", cleanupFunction(_from))
+				.render();
+			break;
+		}
+		case Type::Category::FixedPoint:
+			solUnimplemented("Fixed point types not implemented.");
+			break;
+		case Type::Category::Array:
+			solUnimplementedAssert(false, "Array conversion not implemented.");
+			break;
+		case Type::Category::Struct:
+			solUnimplementedAssert(false, "Struct conversion not implemented.");
+			break;
+		case Type::Category::FixedBytes:
+		{
+			FixedBytesType const& from = dynamic_cast<FixedBytesType const&>(_from);
+			if (toCategory == Type::Category::Integer)
+				body =
+					Whiskers("converted := <convert>(<shift>(value))")
+					("shift", shiftRightFunction(256 - from.numBytes() * 8, false))
+					("convert", conversionFunction(IntegerType(from.numBytes() * 8), _to))
+					.render();
+			else
+			{
+				// clear for conversion to longer bytes
+				solAssert(toCategory == Type::Category::FixedBytes, "Invalid type conversion requested.");
+				body =
+					Whiskers("converted := <clean>(value)")
+					("clean", cleanupFunction(from))
+					.render();
+			}
+			break;
+		}
+		case Type::Category::Function:
+		{
+			solAssert(false, "Conversion should not be called for function types.");
+			break;
+		}
+		case Type::Category::Enum:
+		{
+			solAssert(toCategory == Type::Category::Integer || _from == _to, "");
+			EnumType const& enumType = dynamic_cast<decltype(enumType)>(_from);
+			body =
+				Whiskers("converted := <clean>(value)")
+				("clean", cleanupFunction(enumType))
+				.render();
+			break;
+		}
+		case Type::Category::Tuple:
+		{
+			solUnimplementedAssert(false, "Tuple conversion not implemented.");
+			break;
+		}
+		default:
+			solAssert(false, "");
+		}
+
+		solAssert(!body.empty(), "");
+		templ("body", body);
+		return templ.render();
+	});
+}
+
+string ABIFunctions::cleanupCombinedExternalFunctionIdFunction()
+{
+	string functionName = "cleanup_combined_external_function_id";
+	return createFunction(functionName, [&]() {
+		return Whiskers(R"(
+			function <functionName>(addr_and_selector) -> cleaned {
+				cleaned := <clean>(addr_and_selector)
+			}
+		)")
+		("functionName", functionName)
+		("clean", cleanupFunction(FixedBytesType(24)))
+		.render();
+	});
+}
+
+string ABIFunctions::combineExternalFunctionIdFunction()
+{
+	string functionName = "combine_external_function_id";
+	return createFunction(functionName, [&]() {
+		return Whiskers(R"(
+			function <functionName>(addr, selector) -> combined {
+				combined := <shl64>(or(<shl32>(addr), and(selector, 0xffffffff)))
+			}
+		)")
+		("functionName", functionName)
+		("shl32", shiftLeftFunction(32))
+		("shl64", shiftLeftFunction(64))
+		.render();
+	});
+}
+
+string ABIFunctions::abiEncodingFunction(
+	Type const& _from,
+	Type const& _to,
+	bool _encodeAsLibraryTypes,
+	bool _compacted
+)
+{
+	solUnimplementedAssert(
+		_to.mobileType() &&
+		_to.mobileType()->interfaceType(_encodeAsLibraryTypes) &&
+		_to.mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType(),
+		"Encoding type \"" + _to.toString() + "\" not yet implemented."
+	);
+	TypePointer toInterface = _to.mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType();
+	Type const& to = *toInterface;
+
+	if (_from.category() == Type::Category::StringLiteral)
+		return abiEncodingFunctionStringLiteral(_from, to, _encodeAsLibraryTypes);
+	else if (auto toArray = dynamic_cast<ArrayType const*>(&to))
+	{
+		solAssert(_from.category() == Type::Category::Array, "");
+		solAssert(to.dataStoredIn(DataLocation::Memory), "");
+		ArrayType const& fromArray = dynamic_cast<ArrayType const&>(_from);
+		if (fromArray.location() == DataLocation::CallData)
+			return abiEncodingFunctionCalldataArray(fromArray, *toArray, _encodeAsLibraryTypes);
+		else if (!fromArray.isByteArray() && (
+				fromArray.location() == DataLocation::Memory ||
+				fromArray.baseType()->storageBytes() > 16
+		))
+			return abiEncodingFunctionSimpleArray(fromArray, *toArray, _encodeAsLibraryTypes);
+		else if (fromArray.location() == DataLocation::Memory)
+			return abiEncodingFunctionMemoryByteArray(fromArray, *toArray, _encodeAsLibraryTypes);
+		else if (fromArray.location() == DataLocation::Storage)
+			return abiEncodingFunctionCompactStorageArray(fromArray, *toArray, _encodeAsLibraryTypes);
+		else
+			solAssert(false, "");
+	}
+	else if (dynamic_cast<StructType const*>(&to))
+	{
+		solUnimplementedAssert(false, "Structs not yet implemented.");
+	}
+	else if (_from.category() == Type::Category::Function)
+		return abiEncodingFunctionFunctionType(
+			dynamic_cast<FunctionType const&>(_from),
+			to,
+			_encodeAsLibraryTypes,
+			_compacted
+		);
+
+	solAssert(_from.sizeOnStack() == 1, "");
+	solAssert(to.isValueType(), "");
+	solAssert(to.calldataEncodedSize() == 32, "");
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		to.identifier() +
+		(_encodeAsLibraryTypes ? "_library" : "");
+	return createFunction(functionName, [&]() {
+		solAssert(!to.isDynamicallyEncoded(), "");
+
+		Whiskers templ(R"(
+			function <functionName>(value, pos) {
+				mstore(pos, <cleanupConvert>)
+			}
+		)");
+		templ("functionName", functionName);
+
+		if (_from.dataStoredIn(DataLocation::Storage) && to.isValueType())
+		{
+			// special case: convert storage reference type to value type - this is only
+			// possible for library calls where we just forward the storage reference
+			solAssert(_encodeAsLibraryTypes, "");
+			solAssert(to == IntegerType(256), "");
+			templ("cleanupConvert", "value");
+		}
+		else
+		{
+			if (_from == to)
+				templ("cleanupConvert", cleanupFunction(_from) + "(value)");
+			else
+				templ("cleanupConvert", conversionFunction(_from, to) + "(value)");
+		}
+		return templ.render();
+	});
+}
+
+string ABIFunctions::abiEncodingFunctionCalldataArray(
+	Type const& _from,
+	Type const& _to,
+	bool _encodeAsLibraryTypes
+)
+{
+	solAssert(_to.isDynamicallySized(), "");
+	solAssert(_from.category() == Type::Category::Array, "Unknown dynamic type.");
+	solAssert(_to.category() == Type::Category::Array, "Unknown dynamic type.");
+	auto const& fromArrayType = dynamic_cast<ArrayType const&>(_from);
+	auto const& toArrayType = dynamic_cast<ArrayType const&>(_to);
+
+	solAssert(fromArrayType.location() == DataLocation::CallData, "");
+
+	solAssert(
+		*fromArrayType.copyForLocation(DataLocation::Memory, true) ==
+		*toArrayType.copyForLocation(DataLocation::Memory, true),
+		""
+	);
+
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier() +
+		(_encodeAsLibraryTypes ? "_library" : "");
+	return createFunction(functionName, [&]() {
+		solUnimplementedAssert(fromArrayType.isByteArray(), "");
+		// TODO if this is not a byte array, we might just copy byte-by-byte anyway,
+		// because the encoding is position-independent, but we have to check that.
+		Whiskers templ(R"(
+			function <functionName>(start, length, pos) -> end {
+				<storeLength> // might update pos
+				<copyFun>(start, pos, length)
+				end := add(pos, <roundUpFun>(length))
+			}
+		)");
+		templ("storeLength", _to.isDynamicallySized() ? "mstore(pos, length) pos := add(pos, 0x20)" : "");
+		templ("functionName", functionName);
+		templ("copyFun", copyToMemoryFunction(true));
+		templ("roundUpFun", roundUpFunction());
+		return templ.render();
+	});
+}
+
+string ABIFunctions::abiEncodingFunctionSimpleArray(
+	ArrayType const& _from,
+	ArrayType const& _to,
+	bool _encodeAsLibraryTypes
+)
+{
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier() +
+		(_encodeAsLibraryTypes ? "_library" : "");
+
+	solAssert(_from.isDynamicallySized() == _to.isDynamicallySized(), "");
+	solAssert(_from.length() == _to.length(), "");
+	solAssert(_from.dataStoredIn(DataLocation::Memory) || _from.dataStoredIn(DataLocation::Storage), "");
+	solAssert(!_from.isByteArray(), "");
+	solAssert(_from.dataStoredIn(DataLocation::Memory) || _from.baseType()->storageBytes() > 16, "");
+
+	return createFunction(functionName, [&]() {
+		bool dynamic = _to.isDynamicallyEncoded();
+		bool dynamicBase = _to.baseType()->isDynamicallyEncoded();
+		bool inMemory = _from.dataStoredIn(DataLocation::Memory);
+		Whiskers templ(
+			dynamicBase ?
+			R"(
+				function <functionName>(value, pos) <return> {
+					let length := <lengthFun>(value)
+					<storeLength> // might update pos
+					let headStart := pos
+					let tail := add(pos, mul(length, 0x20))
+					let srcPtr := <dataAreaFun>(value)
+					for { let i := 0 } lt(i, length) { i := add(i, 1) }
+					{
+						mstore(pos, sub(tail, headStart))
+						tail := <encodeToMemoryFun>(<arrayElementAccess>(srcPtr), tail)
+						srcPtr := <nextArrayElement>(srcPtr)
+						pos := add(pos, <elementEncodedSize>)
+					}
+					pos := tail
+					<assignEnd>
+				}
+			)" :
+			R"(
+				function <functionName>(value, pos) <return> {
+					let length := <lengthFun>(value)
+					<storeLength> // might update pos
+					let srcPtr := <dataAreaFun>(value)
+					for { let i := 0 } lt(i, length) { i := add(i, 1) }
+					{
+						<encodeToMemoryFun>(<arrayElementAccess>(srcPtr), pos)
+						srcPtr := <nextArrayElement>(srcPtr)
+						pos := add(pos, <elementEncodedSize>)
+					}
+					<assignEnd>
+				}
+			)"
+		);
+		templ("functionName", functionName);
+		templ("return", dynamic ? " -> end " : "");
+		templ("assignEnd", dynamic ? "end := pos" : "");
+		templ("lengthFun", arrayLengthFunction(_from));
+		if (_to.isDynamicallySized())
+			templ("storeLength", "mstore(pos, length) pos := add(pos, 0x20)");
+		else
+			templ("storeLength", "");
+		templ("dataAreaFun", arrayDataAreaFunction(_from));
+		templ("elementEncodedSize", toCompactHexWithPrefix(_to.baseType()->calldataEncodedSize()));
+		templ("encodeToMemoryFun", abiEncodingFunction(
+			*_from.baseType(),
+			*_to.baseType(),
+			_encodeAsLibraryTypes,
+			true
+		));
+		templ("arrayElementAccess", inMemory ? "mload" : "sload");
+		templ("nextArrayElement", nextArrayElementFunction(_from));
+		return templ.render();
+	});
+}
+
+string ABIFunctions::abiEncodingFunctionMemoryByteArray(
+	ArrayType const& _from,
+	ArrayType const& _to,
+	bool _encodeAsLibraryTypes
+)
+{
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier() +
+		(_encodeAsLibraryTypes ? "_library" : "");
+
+	solAssert(_from.isDynamicallySized() == _to.isDynamicallySized(), "");
+	solAssert(_from.length() == _to.length(), "");
+	solAssert(_from.dataStoredIn(DataLocation::Memory), "");
+	solAssert(_from.isByteArray(), "");
+
+	return createFunction(functionName, [&]() {
+		solAssert(_to.isByteArray(), "");
+		Whiskers templ(R"(
+			function <functionName>(value, pos) -> end {
+				let length := <lengthFun>(value)
+				mstore(pos, length)
+				<copyFun>(add(value, 0x20), add(pos, 0x20), length)
+				end := add(add(pos, 0x20), <roundUpFun>(length))
+			}
+		)");
+		templ("functionName", functionName);
+		templ("lengthFun", arrayLengthFunction(_from));
+		templ("copyFun", copyToMemoryFunction(false));
+		templ("roundUpFun", roundUpFunction());
+		return templ.render();
+	});
+}
+
+string ABIFunctions::abiEncodingFunctionCompactStorageArray(
+	ArrayType const& _from,
+	ArrayType const& _to,
+	bool _encodeAsLibraryTypes
+)
+{
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier() +
+		(_encodeAsLibraryTypes ? "_library" : "");
+
+	solAssert(_from.isDynamicallySized() == _to.isDynamicallySized(), "");
+	solAssert(_from.length() == _to.length(), "");
+	solAssert(_from.dataStoredIn(DataLocation::Storage), "");
+
+	return createFunction(functionName, [&]() {
+		if (_from.isByteArray())
+		{
+			solAssert(_to.isByteArray(), "");
+			Whiskers templ(R"(
+				function <functionName>(value, pos) -> ret {
+					let slotValue := sload(value)
+					switch and(slotValue, 1)
+					case 0 {
+						// short byte array
+						let length := and(div(slotValue, 2), 0x7f)
+						mstore(pos, length)
+						mstore(add(pos, 0x20), and(slotValue, not(0xff)))
+						ret := add(pos, 0x40)
+					}
+					case 1 {
+						// long byte array
+						let length := div(slotValue, 2)
+						mstore(pos, length)
+						pos := add(pos, 0x20)
+						let dataPos := <arrayDataSlot>(value)
+						let i := 0
+						for { } lt(i, length) { i := add(i, 0x20) } {
+							mstore(add(pos, i), sload(dataPos))
+							dataPos := add(dataPos, 1)
+						}
+						ret := add(pos, i)
+					}
+				}
+			)");
+			templ("functionName", functionName);
+			templ("arrayDataSlot", arrayDataAreaFunction(_from));
+			return templ.render();
+		}
+		else
+		{
+			// Multiple items per slot
+			solAssert(_from.baseType()->storageBytes() <= 16, "");
+			solAssert(!_from.baseType()->isDynamicallyEncoded(), "");
+			solAssert(_from.baseType()->isValueType(), "");
+			bool dynamic = _to.isDynamicallyEncoded();
+			size_t storageBytes = _from.baseType()->storageBytes();
+			size_t itemsPerSlot = 32 / storageBytes;
+			// This always writes full slot contents to memory, which might be
+			// more than desired, i.e. it writes beyond the end of memory.
+			Whiskers templ(
+				R"(
+					function <functionName>(value, pos) <return> {
+						let length := <lengthFun>(value)
+						<storeLength> // might update pos
+						let originalPos := pos
+						let srcPtr := <dataArea>(value)
+						for { let i := 0 } lt(i, length) { i := add(i, <itemsPerSlot>) }
+						{
+							let data := sload(srcPtr)
+							<#items>
+								<encodeToMemoryFun>(<shiftRightFun>(data), pos)
+								pos := add(pos, <elementEncodedSize>)
+							</items>
+							srcPtr := add(srcPtr, 1)
+						}
+						pos := add(originalPos, mul(length, <elementEncodedSize>))
+						<assignEnd>
+					}
+				)"
+			);
+			templ("functionName", functionName);
+			templ("return", dynamic ? " -> end " : "");
+			templ("assignEnd", dynamic ? "end := pos" : "");
+			templ("lengthFun", arrayLengthFunction(_from));
+			if (_to.isDynamicallySized())
+				templ("storeLength", "mstore(pos, length) pos := add(pos, 0x20)");
+			else
+				templ("storeLength", "");
+			templ("dataArea", arrayDataAreaFunction(_from));
+			templ("itemsPerSlot", to_string(itemsPerSlot));
+			string elementEncodedSize = toCompactHexWithPrefix(_to.baseType()->calldataEncodedSize());
+			templ("elementEncodedSize", elementEncodedSize);
+			string encodeToMemoryFun = abiEncodingFunction(
+				*_from.baseType(),
+				*_to.baseType(),
+				_encodeAsLibraryTypes,
+				true
+			);
+			templ("encodeToMemoryFun", encodeToMemoryFun);
+			std::vector<std::map<std::string, std::string>> items(itemsPerSlot);
+			for (size_t i = 0; i < itemsPerSlot; ++i)
+				items[i]["shiftRightFun"] = shiftRightFunction(i * storageBytes * 8, false);
+			templ("items", items);
+			return templ.render();
+		}
+	});
+}
+
+string ABIFunctions::abiEncodingFunctionStringLiteral(
+	Type const& _from,
+	Type const& _to,
+	bool _encodeAsLibraryTypes
+)
+{
+	solAssert(_from.category() == Type::Category::StringLiteral, "");
+
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier() +
+		(_encodeAsLibraryTypes ? "_library" : "");
+	return createFunction(functionName, [&]() {
+		auto const& strType = dynamic_cast<StringLiteralType const&>(_from);
+		string const& value = strType.value();
+		solAssert(_from.sizeOnStack() == 0, "");
+
+		if (_to.isDynamicallySized())
+		{
+			Whiskers templ(R"(
+				function <functionName>(pos) -> end {
+					mstore(pos, <length>)
+					<#word>
+						mstore(add(pos, <offset>), <wordValue>)
+					</word>
+					end := add(pos, <overallSize>)
+				}
+			)");
+			templ("functionName", functionName);
+
+			// TODO this can make use of CODECOPY for large strings once we have that in JULIA
+			size_t words = (value.size() + 31) / 32;
+			templ("overallSize", to_string(32 + words * 32));
+			templ("length", to_string(value.size()));
+			vector<map<string, string>> wordParams(words);
+			for (size_t i = 0; i < words; ++i)
+			{
+				wordParams[i]["offset"] = to_string(32 + i * 32);
+				wordParams[i]["wordValue"] = "0x" + h256(value.substr(32 * i, 32), h256::AlignLeft).hex();
+			}
+			templ("word", wordParams);
+			return templ.render();
+		}
+		else
+		{
+			solAssert(_to.category() == Type::Category::FixedBytes, "");
+			solAssert(value.size() <= 32, "");
+			Whiskers templ(R"(
+				function <functionName>(pos) {
+					mstore(pos, <wordValue>)
+				}
+			)");
+			templ("functionName", functionName);
+			templ("wordValue", "0x" + h256(value, h256::AlignLeft).hex());
+			return templ.render();
+		}
+	});
+}
+
+string ABIFunctions::abiEncodingFunctionFunctionType(
+	FunctionType const& _from,
+	Type const& _to,
+	bool _encodeAsLibraryTypes,
+	bool _compacted
+)
+{
+	solAssert(_from.kind() == FunctionType::Kind::External, "");
+	solAssert(_from == _to, "");
+
+	string functionName =
+		"abi_encode_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier() +
+		(_compacted ? "_compacted" : "") +
+		(_encodeAsLibraryTypes ? "_library" : "");
+
+	if (_compacted)
+	{
+		return createFunction(functionName, [&]() {
+			return Whiskers(R"(
+				function <functionName>(addr_and_function_id, pos) {
+					mstore(pos, <cleanExtFun>(addr_and_function_id))
+				}
+			)")
+			("functionName", functionName)
+			("cleanExtFun", cleanupCombinedExternalFunctionIdFunction())
+			.render();
+		});
+	}
+	else
+	{
+		return createFunction(functionName, [&]() {
+			return Whiskers(R"(
+				function <functionName>(addr, function_id, pos) {
+					mstore(pos, <combineExtFun>(addr, function_id))
+				}
+			)")
+			("functionName", functionName)
+			("combineExtFun", combineExternalFunctionIdFunction())
+			.render();
+		});
+	}
+}
+
+string ABIFunctions::copyToMemoryFunction(bool _fromCalldata)
+{
+	string functionName = "copy_" + string(_fromCalldata ? "calldata" : "memory") + "_to_memory";
+	return createFunction(functionName, [&]() {
+		if (_fromCalldata)
+		{
+			return Whiskers(R"(
+				function <functionName>(src, dst, length) {
+					calldatacopy(dst, src, length)
+					// clear end
+					mstore(add(dst, length), 0)
+				}
+			)")
+			("functionName", functionName)
+			.render();
+		}
+		else
+		{
+			return Whiskers(R"(
+				function <functionName>(src, dst, length) {
+					let i := 0
+					for { } lt(i, length) { i := add(i, 32) }
+					{
+						mstore(add(dst, i), mload(add(src, i)))
+					}
+					switch eq(i, length)
+					case 0 {
+						// clear end
+						mstore(add(dst, length), 0)
+					}
+				}
+			)")
+			("functionName", functionName)
+			.render();
+		}
+	});
+}
+
+string ABIFunctions::shiftLeftFunction(size_t _numBits)
+{
+	string functionName = "shift_left_" + to_string(_numBits);
+	return createFunction(functionName, [&]() {
+		solAssert(_numBits < 256, "");
+		return
+			Whiskers(R"(function <functionName>(value) -> newValue {
+				newValue := mul(value, <multiplier>)
+			})")
+			("functionName", functionName)
+			("multiplier", toCompactHexWithPrefix(u256(1) << _numBits))
+			.render();
+	});
+}
+
+string ABIFunctions::shiftRightFunction(size_t _numBits, bool _signed)
+{
+	string functionName = "shift_right_" + to_string(_numBits) + (_signed ? "_signed" : "_unsigned");
+	return createFunction(functionName, [&]() {
+		solAssert(_numBits < 256, "");
+		return
+			Whiskers(R"(function <functionName>(value) -> newValue {
+				newValue := <div>(value, <multiplier>)
+			})")
+			("functionName", functionName)
+			("div", _signed ? "sdiv" : "div")
+			("multiplier", toCompactHexWithPrefix(u256(1) << _numBits))
+			.render();
+	});
+}
+
+string ABIFunctions::roundUpFunction()
+{
+	string functionName = "round_up_to_mul_of_32";
+	return createFunction(functionName, [&]() {
+		return
+			Whiskers(R"(function <functionName>(value) -> result {
+				result := and(add(value, 31), not(31))
+			})")
+			("functionName", functionName)
+			.render();
+	});
+}
+
+string ABIFunctions::arrayLengthFunction(ArrayType const& _type)
+{
+	string functionName = "array_length_" + _type.identifier();
+	return createFunction(functionName, [&]() {
+		Whiskers w(R"(
+			function <functionName>(value) -> length {
+				<body>
+			}
+		)");
+		w("functionName", functionName);
+		string body;
+		if (!_type.isDynamicallySized())
+			body = "length := " + toCompactHexWithPrefix(_type.length());
+		else
+		{
+			switch (_type.location())
+			{
+			case DataLocation::CallData:
+				solAssert(false, "called regular array length function on calldata array");
+				break;
+			case DataLocation::Memory:
+				body = "length := mload(value)";
+				break;
+			case DataLocation::Storage:
+				if (_type.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.
+					body = R"(
+						length := sload(value)
+						let mask := sub(mul(0x100, iszero(and(length, 1))), 1)
+						length := div(and(length, mask), 2)
+					)";
+				}
+				else
+					body = "length := sload(value)";
+				break;
+			}
+		}
+		solAssert(!body.empty(), "");
+		w("body", body);
+		return w.render();
+	});
+}
+
+string ABIFunctions::arrayDataAreaFunction(ArrayType const& _type)
+{
+	string functionName = "array_dataslot_" + _type.identifier();
+	return createFunction(functionName, [&]() {
+		if (_type.dataStoredIn(DataLocation::Memory))
+		{
+			if (_type.isDynamicallySized())
+				return Whiskers(R"(
+					function <functionName>(memPtr) -> dataPtr {
+						dataPtr := add(memPtr, 0x20)
+					}
+				)")
+				("functionName", functionName)
+				.render();
+			else
+				return Whiskers(R"(
+					function <functionName>(memPtr) -> dataPtr {
+						dataPtr := memPtr
+					}
+				)")
+				("functionName", functionName)
+				.render();
+		}
+		else if (_type.dataStoredIn(DataLocation::Storage))
+		{
+			if (_type.isDynamicallySized())
+			{
+				Whiskers w(R"(
+					function <functionName>(slot) -> dataSlot {
+						mstore(0, slot)
+						dataSlot := keccak256(0, 0x20)
+					}
+				)");
+				w("functionName", functionName);
+				return w.render();
+			}
+			else
+			{
+				Whiskers w(R"(
+					function <functionName>(slot) -> dataSlot {
+						dataSlot := slot
+					}
+				)");
+				w("functionName", functionName);
+				return w.render();
+			}
+		}
+		else
+		{
+			// Not used for calldata
+			solAssert(false, "");
+		}
+	});
+}
+
+string ABIFunctions::nextArrayElementFunction(ArrayType const& _type)
+{
+	solAssert(!_type.isByteArray(), "");
+	solAssert(
+		_type.location() == DataLocation::Memory ||
+		_type.location() == DataLocation::Storage,
+		""
+	);
+	solAssert(
+		_type.location() == DataLocation::Memory ||
+		_type.baseType()->storageBytes() > 16,
+		""
+	);
+	string functionName = "array_nextElement_" + _type.identifier();
+	return createFunction(functionName, [&]() {
+		if (_type.location() == DataLocation::Memory)
+			return Whiskers(R"(
+				function <functionName>(memPtr) -> nextPtr {
+					nextPtr := add(memPtr, 0x20)
+				}
+			)")
+			("functionName", functionName)
+			.render();
+		else if (_type.location() == DataLocation::Storage)
+			return Whiskers(R"(
+				function <functionName>(slot) -> nextSlot {
+					nextSlot := add(slot, 1)
+				}
+			)")
+			("functionName", functionName)
+			.render();
+		else
+			solAssert(false, "");
+	});
+}
+
+string ABIFunctions::createFunction(string const& _name, function<string ()> const& _creator)
+{
+	if (!m_requestedFunctions.count(_name))
+	{
+		auto fun = _creator();
+		solAssert(!fun.empty(), "");
+		m_requestedFunctions[_name] = fun;
+	}
+	return _name;
+}
+
+size_t ABIFunctions::headSize(TypePointers const& _targetTypes)
+{
+	size_t headSize = 0;
+	for (auto const& t: _targetTypes)
+	{
+		if (t->isDynamicallyEncoded())
+			headSize += 0x20;
+		else
+		{
+			solAssert(t->calldataEncodedSize() > 0, "");
+			headSize += t->calldataEncodedSize();
+		}
+	}
+
+	return headSize;
+}
author	chriseth <chris@ethereum.org>	2017-08-07 22:43:26 +0800
committer	chriseth <chris@ethereum.org>	2017-08-14 18:44:25 +0800
commit	42fe8a2cb1530a557365d47878144c05687b859b (patch)
tree	1de65fdcf1726af091fe661c9a3af3f1841b06ea /libsolidity/codegen/ABIFunctions.cpp
parent	bda410bb071e0d66f393aed3ee9f96d68a8fbb41 (diff)
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