solidity/libsolidity/codegen/YulUtilFunctions.h
2020-01-07 15:51:50 +01:00

296 lines
12 KiB
C++

/*
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/>.
*/
/**
* Component that can generate various useful Yul functions.
*/
#pragma once
#include <liblangutil/EVMVersion.h>
#include <libsolidity/codegen/MultiUseYulFunctionCollector.h>
#include <memory>
#include <string>
#include <vector>
namespace solidity::frontend
{
class Type;
class ArrayType;
class MappingType;
class IntegerType;
/**
* Component that can generate various useful Yul functions.
*/
class YulUtilFunctions
{
public:
explicit YulUtilFunctions(
langutil::EVMVersion _evmVersion,
std::shared_ptr<MultiUseYulFunctionCollector> _functionCollector
):
m_evmVersion(_evmVersion),
m_functionCollector(std::move(_functionCollector))
{}
/// @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 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);
// @returns the name of a function that has the equivalent logic of an
// `assert` or `require` call.
std::string requireOrAssertFunction(bool _assert, Type const* _messageType = nullptr);
/// @returns the name of a function that takes a (cleaned) value of the given value type and
/// left-aligns it, usually for use in non-padded encoding.
std::string leftAlignFunction(Type const& _type);
std::string shiftLeftFunction(size_t _numBits);
std::string shiftLeftFunctionDynamic();
std::string shiftRightFunction(size_t _numBits);
std::string shiftRightFunctionDynamic();
/// @returns the name of a function which replaces the
/// _numBytes bytes starting at byte position _shiftBytes (counted from the least significant
/// byte) by the _numBytes least significant bytes of `toInsert`.
/// signature: (value, toInsert) -> result
std::string updateByteSliceFunction(size_t _numBytes, size_t _shiftBytes);
/// signature: (value, shiftBytes, toInsert) -> result
std::string updateByteSliceFunctionDynamic(size_t _numBytes);
/// @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.
/// signature: (value) -> result
std::string roundUpFunction();
/// signature: (x, y) -> sum
std::string overflowCheckedIntAddFunction(IntegerType const& _type);
/// signature: (x, y) -> product
std::string overflowCheckedIntMulFunction(IntegerType const& _type);
/// @returns name of function to perform division on integers.
/// Checks for division by zero and the special case of
/// signed division of the smallest number by -1.
std::string overflowCheckedIntDivFunction(IntegerType const& _type);
/// @returns name of function to perform modulo on integers.
/// Reverts for modulo by zero.
std::string checkedIntModFunction(IntegerType const& _type);
/// @returns computes the difference between two values.
/// Assumes the input to be in range for the type.
/// signature: (x, y) -> diff
std::string overflowCheckedIntSubFunction(IntegerType const& _type);
/// @returns the name of a function that fetches the length of the given
/// array
/// signature: (array) -> length
std::string arrayLengthFunction(ArrayType const& _type);
/// @returns the name of a function that resizes a storage array
/// signature: (array, newLen)
std::string resizeDynamicArrayFunction(ArrayType const& _type);
/// @returns the name of a function that reduces the size of a storage array by one element
/// signature: (array)
std::string storageArrayPopFunction(ArrayType const& _type);
/// @returns the name of a function that pushes an element to a storage array
/// signature: (array, value)
std::string storageArrayPushFunction(ArrayType const& _type);
/// @returns the name of a function that pushes the base type's zero element to a storage array and returns storage slot and offset of the added element.
/// signature: (array) -> slot, offset
std::string storageArrayPushZeroFunction(ArrayType const& _type);
/// @returns the name of a function that will clear the storage area given
/// by the start and end (exclusive) parameters (slots).
/// signature: (start, end)
std::string clearStorageRangeFunction(Type const& _type);
/// @returns the name of a function that will clear the given storage array
/// signature: (slot) ->
std::string clearStorageArrayFunction(ArrayType const& _type);
/// Returns the name of a function that will convert a given length to the
/// size in memory (number of storage slots or calldata/memory bytes) it
/// will require.
/// signature: (length) -> size
std::string arrayConvertLengthToSize(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
/// a memory pointer or a calldata pointer to the slot number / memory pointer / calldata pointer
/// for the data position of an array which is stored in that slot / memory area / calldata area.
std::string arrayDataAreaFunction(ArrayType const& _type);
/// @returns the name of a function that returns the slot and offset for the
/// given array and index
/// signature: (array, index) -> slot, offset
std::string storageArrayIndexAccessFunction(ArrayType const& _type);
/// @returns the name of a function that returns the memory address for the
/// given array base ref and index.
/// Causes invalid opcode on out of range access.
/// signature: (baseRef, index) -> address
std::string memoryArrayIndexAccessFunction(ArrayType const& _type);
/// @returns the name of a function that returns the calldata address for the
/// given array base ref and index.
/// signature: (baseRef, index) -> address
std::string calldataArrayIndexAccessFunction(ArrayType const& _type);
/// @returns the name of a function that advances an array data pointer to the next element.
/// Only works for memory arrays, calldata arrays and storage arrays that every item occupies one or multiple full slots.
std::string nextArrayElementFunction(ArrayType const& _type);
/// @returns the name of a function that performs index access for mappings.
/// @param _mappingType the type of the mapping
/// @param _keyType the type of the value provided
std::string mappingIndexAccessFunction(MappingType const& _mappingType, Type const& _keyType);
/// @returns a function that reads a value type from storage.
/// Performs bit mask/sign extend cleanup and appropriate left / right shift, but not validation.
/// @param _splitFunctionTypes if false, returns the address and function signature in a
/// single variable.
std::string readFromStorage(Type const& _type, size_t _offset, bool _splitFunctionTypes);
std::string readFromStorageDynamic(Type const& _type, bool _splitFunctionTypes);
/// @returns a function that reads a value type from memory.
/// signature: (addr) -> value
std::string readFromMemory(Type const& _type);
/// @returns a function that reads a value type from calldata.
/// Reverts on invalid input.
/// signature: (addr) -> value
std::string readFromCalldata(Type const& _type);
/// @returns a function that extracts a value type from storage slot that has been
/// retrieved already.
/// Performs bit mask/sign extend cleanup and appropriate left / right shift, but not validation.
/// @param _splitFunctionTypes if false, returns the address and function signature in a
/// single variable.
std::string extractFromStorageValue(Type const& _type, size_t _offset, bool _splitFunctionTypes);
std::string extractFromStorageValueDynamic(Type const& _type, bool _splitFunctionTypes);
/// Returns the name of a function will write the given value to
/// the specified slot and offset. If offset is not given, it is expected as
/// runtime parameter.
/// signature: (slot, [offset,] value)
std::string updateStorageValueFunction(Type const& _type, std::optional<unsigned> const& _offset = std::optional<unsigned>());
/// Returns the name of a function that will write the given value to
/// the specified address.
/// Performs a cleanup before writing for value types.
/// signature: (memPtr, value) ->
std::string writeToMemoryFunction(Type const& _type);
/// Performs cleanup after reading from a potentially compressed storage slot.
/// The function does not perform any validation, it just masks or sign-extends
/// higher order bytes or left-aligns (in case of bytesNN).
/// The storage cleanup expects the value to be right-aligned with potentially
/// dirty higher order bytes.
/// @param _splitFunctionTypes if false, returns the address and function signature in a
/// single variable.
std::string cleanupFromStorageFunction(Type const& _type, bool _splitFunctionTypes);
/// @returns the name of a function that prepares a value of the given type
/// for being stored in storage. This usually includes cleanup and right-alignment
/// to fit the number of bytes in storage.
/// The resulting value might still have dirty higher order bits.
std::string prepareStoreFunction(Type const& _type);
/// @returns the name of a function that allocates memory.
/// Modifies the "free memory pointer"
/// Arguments: size
/// Return value: pointer
std::string allocationFunction();
/// @returns the name of a function that allocates a memory array.
/// For dynamic arrays it adds space for length and stores it.
/// signature: (length) -> memPtr
std::string allocateMemoryArrayFunction(ArrayType const& _type);
/// @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.
///
/// This is used for data being encoded or general type conversions in the code.
std::string conversionFunction(Type const& _from, Type const& _to);
/// @returns the name of the cleanup function for the given type and
/// adds its implementation to the requested functions.
/// The cleanup function defers to the validator function with "assert"
/// if there is no reasonable way to clean a value.
std::string cleanupFunction(Type const& _type);
/// @returns the name of the validator 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.
///
/// This is used for data decoded from external sources.
std::string validatorFunction(Type const& _type, bool _revertOnFailure = false);
std::string packedHashFunction(std::vector<Type const*> const& _givenTypes, std::vector<Type const*> const& _targetTypes);
/// @returns the name of a function that reverts and uses returndata (if available)
/// as reason string.
std::string forwardingRevertFunction();
std::string incrementCheckedFunction(Type const& _type);
std::string decrementCheckedFunction(Type const& _type);
std::string negateNumberCheckedFunction(Type const& _type);
/// @returns the name of a function that returns the zero value for the
/// provided type
std::string zeroValueFunction(Type const& _type);
/// @returns the name of a function that will set the given storage item to
/// zero
/// signature: (slot, offset) ->
std::string storageSetToZeroFunction(Type const& _type);
private:
/// Special case of conversionFunction - handles everything that does not
/// use exactly one variable to hold the value.
std::string conversionFunctionSpecial(Type const& _from, Type const& _to);
std::string readFromMemoryOrCalldata(Type const& _type, bool _fromCalldata);
langutil::EVMVersion m_evmVersion;
std::shared_ptr<MultiUseYulFunctionCollector> m_functionCollector;
};
}