/*
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 Yul code related to ABI encoding, decoding and type conversions.
*/
#pragma once
#include <liblangutil/EVMVersion.h>
#include <libsolidity/ast/ASTForward.h>
#include <vector>
#include <functional>
#include <set>
#include <map>
namespace dev {
namespace solidity {
class Type;
class ArrayType;
class StructType;
class FunctionType;
using TypePointer = std::shared_ptr<Type const>;
using TypePointers = std::vector<TypePointer>;
///
/// Class to generate encoding and decoding functions. Also maintains a collection
/// of "functions to be generated" in order to avoid generating the same function
/// multiple times.
///
/// Make sure to include the result of ``requestedFunctions()`` to a block that
/// is visible from the code that was generated here, or use named labels.
class ABIFunctions
{
public:
explicit ABIFunctions(EVMVersion _evmVersion = EVMVersion{}) : m_evmVersion(_evmVersion) {}
/// @returns name of an assembly function to ABI-encode values of @a _givenTypes
/// into memory, converting the types to @a _targetTypes on the fly.
/// Parameters are: <headStart> <value_n> ... <value_1>, i.e.
/// the layout on the stack is <value_1> ... <value_n> <headStart> with
/// the top of the stack on the right.
/// The values represent stack slots. If a type occupies more or less than one
/// stack slot, it takes exactly that number of values.
/// Returns a pointer to the end of the area written in memory.
/// Does not allocate memory (does not change the memory head pointer), but writes
/// to memory starting at $headStart and an unrestricted amount after that.
/// Assigns the end of encoded memory either to $value0 or (if that is not present)
/// to $headStart.
std::string tupleEncoder(
TypePointers const& _givenTypes,
TypePointers const& _targetTypes,
bool _encodeAsLibraryTypes = false
);
/// @returns name of an assembly function to ABI-decode values of @a _types
/// into memory. If @a _fromMemory is true, decodes from memory instead of
/// from calldata.
/// Can allocate memory.
/// Inputs: <source_offset> <source_end> (layout reversed on stack)
/// Outputs: <value0> <value1> ... <valuen>
/// The values represent stack slots. If a type occupies more or less than one
/// stack slot, it takes exactly that number of values.
std::string tupleDecoder(TypePointers const& _types, bool _fromMemory = false);
/// @returns concatenation of all generated functions and a set of the
/// externally used functions.
/// Clears the internal list, i.e. calling it again will result in an
/// empty return value.
std::pair<std::string, std::set<std::string>> requestedFunctions();
private:
/// @returns the name of the cleanup function for the given type and
/// adds its implementation to the requested functions.
/// @param _revertOnFailure if true, causes revert on invalid data,
/// otherwise an assertion failure.
std::string cleanupFunction(Type const& _type, bool _revertOnFailure = false);
/// @returns the name of the function that converts a value of type @a _from
/// to a value of type @a _to. The resulting vale is guaranteed to be in range
/// (i.e. "clean"). Asserts on failure.
std::string conversionFunction(Type const& _from, Type const& _to);
std::string cleanupCombinedExternalFunctionIdFunction();
/// @returns a function that combines the address and selector to a single value
/// for use in the ABI.
std::string combineExternalFunctionIdFunction();
/// @returns a function that splits the address and selector from a single value
/// for use in the ABI.
std::string splitExternalFunctionIdFunction();
/// @returns the name of the ABI encoding function with the given type
/// and queues the generation of the function to the requested functions.
/// @param _fromStack if false, the input value was just loaded from storage
/// or memory and thus might be compacted into a single slot (depending on the type).
std::string abiEncodingFunction(
Type const& _givenType,
Type const& _targetType,
bool _encodeAsLibraryTypes,
bool _fromStack
);
/// Part of @a abiEncodingFunction for array target type and given calldata array.
std::string abiEncodingFunctionCalldataArray(
Type const& _givenType,
Type const& _targetType,
bool _encodeAsLibraryTypes
);
/// Part of @a abiEncodingFunction for array target type and given memory array or
/// a given storage array with one item per slot.
std::string abiEncodingFunctionSimpleArray(
ArrayType const& _givenType,
ArrayType const& _targetType,
bool _encodeAsLibraryTypes
);
std::string abiEncodingFunctionMemoryByteArray(
ArrayType const& _givenType,
ArrayType const& _targetType,
bool _encodeAsLibraryTypes
);
/// Part of @a abiEncodingFunction for array target type and given storage array
/// where multiple items are packed into the same storage slot.
std::string abiEncodingFunctionCompactStorageArray(
ArrayType const& _givenType,
ArrayType const& _targetType,
bool _encodeAsLibraryTypes
);
/// Part of @a abiEncodingFunction for struct types.
std::string abiEncodingFunctionStruct(
StructType const& _givenType,
StructType const& _targetType,
bool _encodeAsLibraryTypes
);
// @returns the name of the ABI encoding function with the given type
// and queues the generation of the function to the requested functions.
// Case for _givenType being a string literal
std::string abiEncodingFunctionStringLiteral(
Type const& _givenType,
Type const& _targetType,
bool _encodeAsLibraryTypes
);
std::string abiEncodingFunctionFunctionType(
FunctionType const& _from,
Type const& _to,
bool _encodeAsLibraryTypes,
bool _fromStack
);
/// @returns the name of the ABI decoding function for the given type
/// and queues the generation of the function to the requested functions.
/// The caller has to ensure that no out of bounds access (at least to the static
/// part) can happen inside this function.
/// @param _fromMemory if decoding from memory instead of from calldata
/// @param _forUseOnStack if the decoded value is stored on stack or in memory.
std::string abiDecodingFunction(
Type const& _Type,
bool _fromMemory,
bool _forUseOnStack
);
/// Part of @a abiDecodingFunction for value types.
std::string abiDecodingFunctionValueType(Type const& _type, bool _fromMemory);
/// Part of @a abiDecodingFunction for "regular" array types.
std::string abiDecodingFunctionArray(ArrayType const& _type, bool _fromMemory);
/// Part of @a abiDecodingFunction for calldata array types.
std::string abiDecodingFunctionCalldataArray(ArrayType const& _type);
/// Part of @a abiDecodingFunction for byte array types.
std::string abiDecodingFunctionByteArray(ArrayType const& _type, bool _fromMemory);
/// Part of @a abiDecodingFunction for struct types.
std::string abiDecodingFunctionStruct(StructType const& _type, bool _fromMemory);
/// Part of @a abiDecodingFunction for array types.
std::string abiDecodingFunctionFunctionType(FunctionType const& _type, bool _fromMemory, bool _forUseOnStack);
/// @returns a function that copies raw bytes of dynamic length from calldata
/// or memory to memory.
/// Pads with zeros and might write more than exactly length.
std::string copyToMemoryFunction(bool _fromCalldata);
std::string shiftLeftFunction(size_t _numBits);
std::string shiftRightFunction(size_t _numBits);
/// @returns the name of a function that rounds its input to the next multiple
/// of 32 or the input if it is a multiple of 32.
std::string roundUpFunction();
std::string arrayLengthFunction(ArrayType const& _type);
/// @returns the name of a function that computes the number of bytes required
/// to store an array in memory given its length (internally encoded, not ABI encoded).
/// The function reverts for too large lengths.
std::string arrayAllocationSizeFunction(ArrayType const& _type);
/// @returns the name of a function that converts a storage slot number
/// or a memory pointer to the slot number / memory pointer for the data position of an array
/// which is stored in that slot / memory area.
std::string arrayDataAreaFunction(ArrayType const& _type);
/// @returns the name of a function that advances an array data pointer to the next element.
/// Only works for memory arrays and storage arrays that store one item per slot.
std::string nextArrayElementFunction(ArrayType const& _type);
/// @returns the name of a function that allocates memory.
/// Modifies the "free memory pointer"
/// Arguments: size
/// Return value: pointer
std::string allocationFunction();
/// Helper function that uses @a _creator to create a function and add it to
/// @a m_requestedFunctions if it has not been created yet and returns @a _name in both
/// cases.
std::string createFunction(std::string const& _name, std::function<std::string()> const& _creator);
/// Helper function that uses @a _creator to create a function and add it to
/// @a m_requestedFunctions if it has not been created yet and returns @a _name in both
/// cases. Also adds it to the list of externally used functions.
std::string createExternallyUsedFunction(std::string const& _name, std::function<std::string()> const& _creator);
/// @returns the size of the static part of the encoding of the given types.
static size_t headSize(TypePointers const& _targetTypes);
/// Map from function name to code for a multi-use function.
std::map<std::string, std::string> m_requestedFunctions;
std::set<std::string> m_externallyUsedFunctions;
EVMVersion m_evmVersion;
};
}
}
