solidity/libsolidity/codegen/YulUtilFunctions.cpp

802 lines
23 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.
*/
#include <libsolidity/codegen/YulUtilFunctions.h>
#include <libsolidity/codegen/MultiUseYulFunctionCollector.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/codegen/CompilerUtils.h>
#include <libdevcore/Whiskers.h>
#include <boost/algorithm/string/join.hpp>
#include <boost/range/adaptor/reversed.hpp>
using namespace std;
using namespace dev;
using namespace dev::solidity;
string YulUtilFunctions::combineExternalFunctionIdFunction()
{
string functionName = "combine_external_function_id";
return m_functionCollector->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 YulUtilFunctions::splitExternalFunctionIdFunction()
{
string functionName = "split_external_function_id";
return m_functionCollector->createFunction(functionName, [&]() {
return Whiskers(R"(
function <functionName>(combined) -> addr, selector {
combined := <shr64>(combined)
selector := and(combined, 0xffffffff)
addr := <shr32>(combined)
}
)")
("functionName", functionName)
("shr32", shiftRightFunction(32))
("shr64", shiftRightFunction(64))
.render();
});
}
string YulUtilFunctions::copyToMemoryFunction(bool _fromCalldata)
{
string functionName = "copy_" + string(_fromCalldata ? "calldata" : "memory") + "_to_memory";
return m_functionCollector->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)))
}
if gt(i, length)
{
// clear end
mstore(add(dst, length), 0)
}
}
)")
("functionName", functionName)
.render();
}
});
}
string YulUtilFunctions::leftAlignFunction(Type const& _type)
{
string functionName = string("leftAlign_") + _type.identifier();
return m_functionCollector->createFunction(functionName, [&]() {
Whiskers templ(R"(
function <functionName>(value) -> aligned {
<body>
}
)");
templ("functionName", functionName);
switch (_type.category())
{
case Type::Category::Address:
templ("body", "aligned := " + leftAlignFunction(IntegerType(160)) + "(value)");
break;
case Type::Category::Integer:
{
IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
if (type.numBits() == 256)
templ("body", "aligned := value");
else
templ("body", "aligned := " + shiftLeftFunction(256 - type.numBits()) + "(value)");
break;
}
case Type::Category::RationalNumber:
solAssert(false, "Left align requested for rational number.");
break;
case Type::Category::Bool:
templ("body", "aligned := " + leftAlignFunction(IntegerType(8)) + "(value)");
break;
case Type::Category::FixedPoint:
solUnimplemented("Fixed point types not implemented.");
break;
case Type::Category::Array:
case Type::Category::Struct:
solAssert(false, "Left align requested for non-value type.");
break;
case Type::Category::FixedBytes:
templ("body", "aligned := value");
break;
case Type::Category::Contract:
templ("body", "aligned := " + leftAlignFunction(*TypeProvider::address()) + "(value)");
break;
case Type::Category::Enum:
{
unsigned storageBytes = dynamic_cast<EnumType const&>(_type).storageBytes();
templ("body", "aligned := " + leftAlignFunction(IntegerType(8 * storageBytes)) + "(value)");
break;
}
case Type::Category::InaccessibleDynamic:
solAssert(false, "Left align requested for inaccessible dynamic type.");
break;
default:
solAssert(false, "Left align of type " + _type.identifier() + " requested.");
}
return templ.render();
});
}
string YulUtilFunctions::shiftLeftFunction(size_t _numBits)
{
solAssert(_numBits < 256, "");
string functionName = "shift_left_" + to_string(_numBits);
if (m_evmVersion.hasBitwiseShifting())
{
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue := shl(<numBits>, value)
}
)")
("functionName", functionName)
("numBits", to_string(_numBits))
.render();
});
}
else
{
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue := mul(value, <multiplier>)
}
)")
("functionName", functionName)
("multiplier", toCompactHexWithPrefix(u256(1) << _numBits))
.render();
});
}
}
string YulUtilFunctions::shiftRightFunction(size_t _numBits)
{
solAssert(_numBits < 256, "");
// Note that if this is extended with signed shifts,
// the opcodes SAR and SDIV behave differently with regards to rounding!
string functionName = "shift_right_" + to_string(_numBits) + "_unsigned";
if (m_evmVersion.hasBitwiseShifting())
{
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue := shr(<numBits>, value)
}
)")
("functionName", functionName)
("numBits", to_string(_numBits))
.render();
});
}
else
{
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue := div(value, <multiplier>)
}
)")
("functionName", functionName)
("multiplier", toCompactHexWithPrefix(u256(1) << _numBits))
.render();
});
}
}
string YulUtilFunctions::roundUpFunction()
{
string functionName = "round_up_to_mul_of_32";
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> result {
result := and(add(value, 31), not(31))
}
)")
("functionName", functionName)
.render();
});
}
string YulUtilFunctions::overflowCheckedUIntAddFunction(size_t _bits)
{
solAssert(0 < _bits && _bits <= 256 && _bits % 8 == 0, "");
string functionName = "checked_add_uint_" + to_string(_bits);
return m_functionCollector->createFunction(functionName, [&]() {
if (_bits < 256)
return
Whiskers(R"(
function <functionName>(x, y) -> sum {
let mask := <mask>
sum := add(and(x, mask), and(y, mask))
if and(sum, not(mask)) { revert(0, 0) }
}
)")
("functionName", functionName)
("mask", toCompactHexWithPrefix((u256(1) << _bits) - 1))
.render();
else
return
Whiskers(R"(
function <functionName>(x, y) -> sum {
sum := add(x, y)
if lt(sum, x) { revert(0, 0) }
}
)")
("functionName", functionName)
.render();
});
}
string YulUtilFunctions::arrayLengthFunction(ArrayType const& _type)
{
string functionName = "array_length_" + _type.identifier();
return m_functionCollector->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 YulUtilFunctions::arrayAllocationSizeFunction(ArrayType const& _type)
{
solAssert(_type.dataStoredIn(DataLocation::Memory), "");
string functionName = "array_allocation_size_" + _type.identifier();
return m_functionCollector->createFunction(functionName, [&]() {
Whiskers w(R"(
function <functionName>(length) -> size {
// Make sure we can allocate memory without overflow
if gt(length, 0xffffffffffffffff) { revert(0, 0) }
size := <allocationSize>
<addLengthSlot>
}
)");
w("functionName", functionName);
if (_type.isByteArray())
// Round up
w("allocationSize", "and(add(length, 0x1f), not(0x1f))");
else
w("allocationSize", "mul(length, 0x20)");
if (_type.isDynamicallySized())
w("addLengthSlot", "size := add(size, 0x20)");
else
w("addLengthSlot", "");
return w.render();
});
}
string YulUtilFunctions::arrayDataAreaFunction(ArrayType const& _type)
{
string functionName = "array_dataslot_" + _type.identifier();
return m_functionCollector->createFunction(functionName, [&]() {
switch (_type.location())
{
case 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();
case 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();
}
case DataLocation::CallData:
{
// Calldata arrays are stored as offset of the data area and length
// on the stack, so the offset already points to the data area.
// This might change, if calldata arrays are stored in a single
// stack slot at some point.
Whiskers w(R"(
function <functionName>(slot) -> dataSlot {
dataSlot := slot
}
)");
w("functionName", functionName);
return w.render();
}
default:
solAssert(false, "");
}
});
}
string YulUtilFunctions::nextArrayElementFunction(ArrayType const& _type)
{
solAssert(!_type.isByteArray(), "");
if (_type.dataStoredIn(DataLocation::Storage))
solAssert(_type.baseType()->storageBytes() > 16, "");
string functionName = "array_nextElement_" + _type.identifier();
return m_functionCollector->createFunction(functionName, [&]() {
switch (_type.location())
{
case DataLocation::Memory:
return Whiskers(R"(
function <functionName>(memPtr) -> nextPtr {
nextPtr := add(memPtr, 0x20)
}
)")
("functionName", functionName)
.render();
case DataLocation::Storage:
return Whiskers(R"(
function <functionName>(slot) -> nextSlot {
nextSlot := add(slot, 1)
}
)")
("functionName", functionName)
.render();
case DataLocation::CallData:
return Whiskers(R"(
function <functionName>(calldataPtr) -> nextPtr {
nextPtr := add(calldataPtr, <stride>)
}
)")
("stride", toCompactHexWithPrefix(_type.baseType()->isDynamicallyEncoded() ? 32 : _type.baseType()->calldataEncodedSize()))
("functionName", functionName)
.render();
default:
solAssert(false, "");
}
});
}
string YulUtilFunctions::allocationFunction()
{
string functionName = "allocateMemory";
return m_functionCollector->createFunction(functionName, [&]() {
return Whiskers(R"(
function <functionName>(size) -> memPtr {
memPtr := mload(<freeMemoryPointer>)
let newFreePtr := add(memPtr, size)
// protect against overflow
if or(gt(newFreePtr, 0xffffffffffffffff), lt(newFreePtr, memPtr)) { revert(0, 0) }
mstore(<freeMemoryPointer>, newFreePtr)
}
)")
("freeMemoryPointer", to_string(CompilerUtils::freeMemoryPointer))
("functionName", functionName)
.render();
});
}
string YulUtilFunctions::conversionFunction(Type const& _from, Type const& _to)
{
string functionName =
"convert_" +
_from.identifier() +
"_to_" +
_to.identifier();
return m_functionCollector->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::Address:
body =
Whiskers("converted := <convert>(value)")
("convert", conversionFunction(IntegerType(160), _to))
.render();
break;
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))
// "mobileType()" returns integer type for rational
("cleanInt", cleanupFunction(*_from.mobileType()))
.render();
}
else if (toCategory == Type::Category::FixedPoint)
solUnimplemented("Not yet implemented - FixedPointType.");
else if (toCategory == Type::Category::Address)
body =
Whiskers("converted := <convert>(value)")
("convert", conversionFunction(_from, IntegerType(160)))
.render();
else
{
solAssert(
toCategory == Type::Category::Integer ||
toCategory == Type::Category::Contract,
"");
IntegerType const addressType(160);
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))
("convert", conversionFunction(IntegerType(from.numBytes() * 8), _to))
.render();
else if (toCategory == Type::Category::Address)
body =
Whiskers("converted := <convert>(value)")
("convert", conversionFunction(_from, IntegerType(160)))
.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(), _from.canonicalName() + " to " + _to.canonicalName());
templ("body", body);
return templ.render();
});
}
string YulUtilFunctions::cleanupFunction(Type const& _type)
{
string functionName = string("cleanup_") + _type.identifier();
return m_functionCollector->createFunction(functionName, [&]() {
Whiskers templ(R"(
function <functionName>(value) -> cleaned {
<body>
}
)");
templ("functionName", functionName);
switch (_type.category())
{
case Type::Category::Address:
templ("body", "cleaned := " + cleanupFunction(IntegerType(160)) + "(value)");
break;
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::Function:
solAssert(dynamic_cast<FunctionType const&>(_type).kind() == FunctionType::Kind::External, "");
templ("body", "cleaned := " + cleanupFunction(FixedBytesType(24)) + "(value)");
break;
case Type::Category::Array:
case Type::Category::Struct:
case Type::Category::Mapping:
solAssert(_type.dataStoredIn(DataLocation::Storage), "Cleanup requested for non-storage reference type.");
templ("body", "cleaned := value");
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)
// This is disallowed in the type system.
solAssert(false, "");
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:
{
AddressType addressType(dynamic_cast<ContractType const&>(_type).isPayable() ?
StateMutability::Payable :
StateMutability::NonPayable
);
templ("body", "cleaned := " + cleanupFunction(addressType) + "(value)");
break;
}
case Type::Category::Enum:
{
// Out of range enums cannot be truncated unambigiously and therefore it should be an error.
templ("body", "cleaned := value " + validatorFunction(_type) + "(value)");
break;
}
case Type::Category::InaccessibleDynamic:
templ("body", "cleaned := 0");
break;
default:
solAssert(false, "Cleanup of type " + _type.identifier() + " requested.");
}
return templ.render();
});
}
string YulUtilFunctions::validatorFunction(Type const& _type, bool _revertOnFailure)
{
string functionName = string("validator_") + (_revertOnFailure ? "revert_" : "assert_") + _type.identifier();
return m_functionCollector->createFunction(functionName, [&]() {
Whiskers templ(R"(
function <functionName>(value) {
if iszero(<condition>) { <failure> }
}
)");
templ("functionName", functionName);
if (_revertOnFailure)
templ("failure", "revert(0, 0)");
else
templ("failure", "invalid()");
switch (_type.category())
{
case Type::Category::Address:
case Type::Category::Integer:
case Type::Category::RationalNumber:
case Type::Category::Bool:
case Type::Category::FixedPoint:
case Type::Category::Function:
case Type::Category::Array:
case Type::Category::Struct:
case Type::Category::Mapping:
case Type::Category::FixedBytes:
case Type::Category::Contract:
{
templ("condition", "eq(value, " + cleanupFunction(_type) + "(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.");
templ("condition", "lt(value, " + to_string(members) + ")");
break;
}
case Type::Category::InaccessibleDynamic:
templ("condition", "1");
break;
default:
solAssert(false, "Validation of type " + _type.identifier() + " requested.");
}
return templ.render();
});
}
string YulUtilFunctions::suffixedVariableNameList(string const& _baseName, size_t _startSuffix, size_t _endSuffix)
{
string result;
if (_startSuffix < _endSuffix)
{
result = _baseName + to_string(_startSuffix++);
while (_startSuffix < _endSuffix)
result += ", " + _baseName + to_string(_startSuffix++);
}
else if (_endSuffix < _startSuffix)
{
result = _baseName + to_string(_endSuffix++);
while (_endSuffix < _startSuffix)
result = _baseName + to_string(_endSuffix++) + ", " + result;
}
return result;
}