/*
This file is part of cpp-ethereum.
cpp-ethereum 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.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Routines used by both the compiler and the expression compiler.
*/
#include <libsolidity/CompilerUtils.h>
#include <libsolidity/AST.h>
#include <libevmcore/Instruction.h>
#include <libevmcore/Params.h>
#include <libsolidity/ArrayUtils.h>
using namespace std;
namespace dev
{
namespace solidity
{
const unsigned CompilerUtils::dataStartOffset = 4;
const size_t CompilerUtils::freeMemoryPointer = 64;
const unsigned CompilerUtils::identityContractAddress = 4;
void CompilerUtils::initialiseFreeMemoryPointer()
{
m_context << u256(freeMemoryPointer + 32);
storeFreeMemoryPointer();
}
void CompilerUtils::fetchFreeMemoryPointer()
{
m_context << u256(freeMemoryPointer) << eth::Instruction::MLOAD;
}
void CompilerUtils::storeFreeMemoryPointer()
{
m_context << u256(freeMemoryPointer) << eth::Instruction::MSTORE;
}
void CompilerUtils::toSizeAfterFreeMemoryPointer()
{
fetchFreeMemoryPointer();
m_context << eth::Instruction::DUP1 << eth::Instruction::SWAP2 << eth::Instruction::SUB;
m_context << eth::Instruction::SWAP1;
}
unsigned CompilerUtils::loadFromMemory(
unsigned _offset,
Type const& _type,
bool _fromCalldata,
bool _padToWordBoundaries
)
{
solAssert(_type.getCategory() != Type::Category::Array, "Unable to statically load dynamic type.");
m_context << u256(_offset);
return loadFromMemoryHelper(_type, _fromCalldata, _padToWordBoundaries);
}
void CompilerUtils::loadFromMemoryDynamic(
Type const& _type,
bool _fromCalldata,
bool _padToWordBoundaries,
bool _keepUpdatedMemoryOffset
)
{
solAssert(_type.getCategory() != Type::Category::Array, "Arrays not yet implemented.");
if (_keepUpdatedMemoryOffset)
m_context << eth::Instruction::DUP1;
unsigned numBytes = loadFromMemoryHelper(_type, _fromCalldata, _padToWordBoundaries);
if (_keepUpdatedMemoryOffset)
{
// update memory counter
moveToStackTop(_type.getSizeOnStack());
m_context << u256(numBytes) << eth::Instruction::ADD;
}
}
unsigned CompilerUtils::storeInMemory(unsigned _offset, Type const& _type, bool _padToWordBoundaries)
{
solAssert(_type.getCategory() != Type::Category::Array, "Unable to statically store dynamic type.");
unsigned numBytes = prepareMemoryStore(_type, _padToWordBoundaries);
if (numBytes > 0)
m_context << u256(_offset) << eth::Instruction::MSTORE;
return numBytes;
}
void CompilerUtils::storeInMemoryDynamic(Type const& _type, bool _padToWordBoundaries)
{
if (_type.getCategory() == Type::Category::Array)
{
auto const& type = dynamic_cast<ArrayType const&>(_type);
solAssert(type.isByteArray(), "Non byte arrays not yet implemented here.");
if (type.location() == ReferenceType::Location::CallData)
{
// stack: target source_offset source_len
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3 << eth::Instruction::DUP5;
// stack: target source_offset source_len source_len source_offset target
m_context << eth::Instruction::CALLDATACOPY;
m_context << eth::Instruction::DUP3 << eth::Instruction::ADD;
m_context << eth::Instruction::SWAP2 << eth::Instruction::POP << eth::Instruction::POP;
}
else if (type.location() == ReferenceType::Location::Memory)
{
// memcpy using the built-in contract
ArrayUtils(m_context).retrieveLength(type);
if (type.isDynamicallySized())
{
// change pointer to data part
m_context << eth::Instruction::SWAP1 << u256(32) << eth::Instruction::ADD;
m_context << eth::Instruction::SWAP1;
}
// stack: <target> <source> <length>
// stack for call: outsize target size source value contract gas
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP4;
m_context << eth::Instruction::DUP2 << eth::Instruction::DUP5;
m_context << u256(0) << u256(identityContractAddress);
//@TODO do not use ::CALL if less than 32 bytes?
//@todo in production, we should not have to pair c_callNewAccountGas.
m_context << u256(eth::c_callGas + 10 + eth::c_callNewAccountGas) << eth::Instruction::GAS;
m_context << eth::Instruction::SUB << eth::Instruction::CALL;
m_context << eth::Instruction::POP; // ignore return value
m_context << eth::Instruction::SWAP1 << eth::Instruction::POP;
// stack: <target> <length>
if (_padToWordBoundaries && (type.isDynamicallySized() || (type.getLength()) % 32 != 0))
{
// stack: <target> <length>
m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD;
// stack: <length> <target + length>
m_context << eth::Instruction::SWAP1 << u256(31) << eth::Instruction::AND;
// stack: <target + length> <remainder = length % 32>
eth::AssemblyItem skip = m_context.newTag();
if (type.isDynamicallySized())
{
m_context << eth::Instruction::DUP1 << eth::Instruction::ISZERO;
m_context.appendConditionalJumpTo(skip);
}
// round off, load from there.
// stack <target + length> <remainder = length % 32>
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3;
m_context << eth::Instruction::SUB;
// stack: target+length remainder <target + length - remainder>
m_context << eth::Instruction::DUP1 << eth::Instruction::MLOAD;
// Now we AND it with ~(2**(8 * (32 - remainder)) - 1)
m_context << u256(1);
m_context << eth::Instruction::DUP4 << u256(32) << eth::Instruction::SUB;
// stack: ...<v> 1 <32 - remainder>
m_context << u256(0x100) << eth::Instruction::EXP << eth::Instruction::SUB;
m_context << eth::Instruction::NOT << eth::Instruction::AND;
// stack: target+length remainder target+length-remainder <v & ...>
m_context << eth::Instruction::DUP2 << eth::Instruction::MSTORE;
// stack: target+length remainder target+length-remainder
m_context << u256(32) << eth::Instruction::ADD;
// stack: target+length remainder <new_padded_end>
m_context << eth::Instruction::SWAP2 << eth::Instruction::POP;
if (type.isDynamicallySized())
m_context << skip.tag();
// stack <target + "length"> <remainder = length % 32>
m_context << eth::Instruction::POP;
}
else
// stack: <target> <length>
m_context << eth::Instruction::ADD;
}
else
{
solAssert(type.location() == ReferenceType::Location::Storage, "");
m_context << eth::Instruction::POP; // remove offset, arrays always start new slot
m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
// stack here: memory_offset storage_offset length_bytes
// jump to end if length is zero
m_context << eth::Instruction::DUP1 << eth::Instruction::ISZERO;
eth::AssemblyItem loopEnd = m_context.newTag();
m_context.appendConditionalJumpTo(loopEnd);
// compute memory end offset
m_context << eth::Instruction::DUP3 << eth::Instruction::ADD << eth::Instruction::SWAP2;
// actual array data is stored at SHA3(storage_offset)
m_context << eth::Instruction::SWAP1;
CompilerUtils(m_context).computeHashStatic();
m_context << eth::Instruction::SWAP1;
// stack here: memory_end_offset storage_data_offset memory_offset
eth::AssemblyItem loopStart = m_context.newTag();
m_context << loopStart;
// load and store
m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD;
m_context << eth::Instruction::DUP2 << eth::Instruction::MSTORE;
// increment storage_data_offset by 1
m_context << eth::Instruction::SWAP1 << u256(1) << eth::Instruction::ADD;
// increment memory offset by 32
m_context << eth::Instruction::SWAP1 << u256(32) << eth::Instruction::ADD;
// check for loop condition
m_context << eth::Instruction::DUP1 << eth::Instruction::DUP4 << eth::Instruction::GT;
m_context.appendConditionalJumpTo(loopStart);
// stack here: memory_end_offset storage_data_offset memory_offset
if (_padToWordBoundaries)
{
// memory_end_offset - start is the actual length (we want to compute the ceil of).
// memory_offset - start is its next multiple of 32, but it might be off by 32.
// so we compute: memory_end_offset += (memory_offset - memory_end_offest) & 31
m_context << eth::Instruction::DUP3 << eth::Instruction::SWAP1 << eth::Instruction::SUB;
m_context << u256(31) << eth::Instruction::AND;
m_context << eth::Instruction::DUP3 << eth::Instruction::ADD;
m_context << eth::Instruction::SWAP2;
}
m_context << loopEnd << eth::Instruction::POP << eth::Instruction::POP;
}
}
else
{
unsigned numBytes = prepareMemoryStore(_type, _padToWordBoundaries);
if (numBytes > 0)
{
solAssert(_type.getSizeOnStack() == 1, "Memory store of types with stack size != 1 not implemented.");
m_context << eth::Instruction::DUP2 << eth::Instruction::MSTORE;
m_context << u256(numBytes) << eth::Instruction::ADD;
}
}
}
void CompilerUtils::encodeToMemory(
TypePointers const& _givenTypes,
TypePointers const& _targetTypes,
bool _padToWordBoundaries,
bool _copyDynamicDataInPlace
)
{
// stack: <v1> <v2> ... <vn> <mem>
TypePointers targetTypes = _targetTypes.empty() ? _givenTypes : _targetTypes;
solAssert(targetTypes.size() == _givenTypes.size(), "");
for (TypePointer& t: targetTypes)
t = t->mobileType()->externalType();
// Stack during operation:
// <v1> <v2> ... <vn> <mem_start> <dyn_head_1> ... <dyn_head_r> <end_of_mem>
// The values dyn_head_i are added during the first loop and they point to the head part
// of the ith dynamic parameter, which is filled once the dynamic parts are processed.
// store memory start pointer
m_context << eth::Instruction::DUP1;
unsigned argSize = CompilerUtils::getSizeOnStack(_givenTypes);
unsigned stackPos = 0; // advances through the argument values
unsigned dynPointers = 0; // number of dynamic head pointers on the stack
for (size_t i = 0; i < _givenTypes.size(); ++i)
{
TypePointer targetType = targetTypes[i];
solAssert(!!targetType, "Externalable type expected.");
if (targetType->isDynamicallySized() && !_copyDynamicDataInPlace)
{
// leave end_of_mem as dyn head pointer
m_context << eth::Instruction::DUP1 << u256(32) << eth::Instruction::ADD;
dynPointers++;
}
else
{
copyToStackTop(argSize - stackPos + dynPointers + 2, _givenTypes[i]->getSizeOnStack());
solAssert(!!targetType, "Externalable type expected.");
TypePointer type = targetType;
if (_givenTypes[i]->isInStorage())
type = _givenTypes[i]; // delay conversion
else
convertType(*_givenTypes[i], *targetType, true);
storeInMemoryDynamic(*type, _padToWordBoundaries);
}
stackPos += _givenTypes[i]->getSizeOnStack();
}
// now copy the dynamic part
// Stack: <v1> <v2> ... <vn> <mem_start> <dyn_head_1> ... <dyn_head_r> <end_of_mem>
stackPos = 0;
unsigned thisDynPointer = 0;
for (size_t i = 0; i < _givenTypes.size(); ++i)
{
TypePointer targetType = targetTypes[i];
solAssert(!!targetType, "Externalable type expected.");
if (targetType->isDynamicallySized() && !_copyDynamicDataInPlace)
{
solAssert(_givenTypes[i]->getCategory() == Type::Category::Array, "Unknown dynamic type.");
auto const& arrayType = dynamic_cast<ArrayType const&>(*_givenTypes[i]);
// copy tail pointer (=mem_end - mem_start) to memory
m_context << eth::dupInstruction(2 + dynPointers) << eth::Instruction::DUP2;
m_context << eth::Instruction::SUB;
m_context << eth::dupInstruction(2 + dynPointers - thisDynPointer);
m_context << eth::Instruction::MSTORE;
// now copy the array
copyToStackTop(argSize - stackPos + dynPointers + 2, arrayType.getSizeOnStack());
// stack: ... <end_of_mem> <value...>
// copy length to memory
m_context << eth::dupInstruction(1 + arrayType.getSizeOnStack());
if (arrayType.location() == ReferenceType::Location::CallData)
m_context << eth::Instruction::DUP2; // length is on stack
else if (arrayType.location() == ReferenceType::Location::Storage)
m_context << eth::Instruction::DUP3 << eth::Instruction::SLOAD;
else
{
solAssert(arrayType.location() == ReferenceType::Location::Memory, "");
m_context << eth::Instruction::DUP2 << eth::Instruction::MLOAD;
}
// stack: ... <end_of_mem> <value...> <end_of_mem'> <length>
storeInMemoryDynamic(IntegerType(256), true);
// stack: ... <end_of_mem> <value...> <end_of_mem''>
// copy the new memory pointer
m_context << eth::swapInstruction(arrayType.getSizeOnStack() + 1) << eth::Instruction::POP;
// stack: ... <end_of_mem''> <value...>
// copy data part
storeInMemoryDynamic(arrayType, true);
// stack: ... <end_of_mem'''>
thisDynPointer++;
}
stackPos += _givenTypes[i]->getSizeOnStack();
}
// remove unneeded stack elements (and retain memory pointer)
m_context << eth::swapInstruction(argSize + dynPointers + 1);
popStackSlots(argSize + dynPointers + 1);
}
void CompilerUtils::convertType(Type const& _typeOnStack, Type const& _targetType, bool _cleanupNeeded)
{
// For a type extension, we need to remove all higher-order bits that we might have ignored in
// previous operations.
// @todo: store in the AST whether the operand might have "dirty" higher order bits
if (_typeOnStack == _targetType && !_cleanupNeeded)
return;
Type::Category stackTypeCategory = _typeOnStack.getCategory();
Type::Category targetTypeCategory = _targetType.getCategory();
switch (stackTypeCategory)
{
case Type::Category::FixedBytes:
{
FixedBytesType const& typeOnStack = dynamic_cast<FixedBytesType const&>(_typeOnStack);
if (targetTypeCategory == Type::Category::Integer)
{
// conversion from bytes to integer. no need to clean the high bit
// only to shift right because of opposite alignment
IntegerType const& targetIntegerType = dynamic_cast<IntegerType const&>(_targetType);
m_context << (u256(1) << (256 - typeOnStack.getNumBytes() * 8)) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
if (targetIntegerType.getNumBits() < typeOnStack.getNumBytes() * 8)
convertType(IntegerType(typeOnStack.getNumBytes() * 8), _targetType, _cleanupNeeded);
}
else
{
// clear lower-order bytes for conversion to shorter bytes - we always clean
solAssert(targetTypeCategory == Type::Category::FixedBytes, "Invalid type conversion requested.");
FixedBytesType const& targetType = dynamic_cast<FixedBytesType const&>(_targetType);
if (targetType.getNumBytes() < typeOnStack.getNumBytes())
{
if (targetType.getNumBytes() == 0)
m_context << eth::Instruction::DUP1 << eth::Instruction::XOR;
else
{
m_context << (u256(1) << (256 - targetType.getNumBytes() * 8));
m_context << eth::Instruction::DUP1 << eth::Instruction::SWAP2;
m_context << eth::Instruction::DIV << eth::Instruction::MUL;
}
}
}
}
break;
case Type::Category::Enum:
solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Enum, "");
break;
case Type::Category::Integer:
case Type::Category::Contract:
case Type::Category::IntegerConstant:
if (targetTypeCategory == Type::Category::FixedBytes)
{
solAssert(stackTypeCategory == Type::Category::Integer || stackTypeCategory == Type::Category::IntegerConstant,
"Invalid conversion to FixedBytesType requested.");
// conversion from bytes to string. no need to clean the high bit
// only to shift left because of opposite alignment
FixedBytesType const& targetBytesType = dynamic_cast<FixedBytesType const&>(_targetType);
if (auto typeOnStack = dynamic_cast<IntegerType const*>(&_typeOnStack))
if (targetBytesType.getNumBytes() * 8 > typeOnStack->getNumBits())
cleanHigherOrderBits(*typeOnStack);
m_context << (u256(1) << (256 - targetBytesType.getNumBytes() * 8)) << eth::Instruction::MUL;
}
else if (targetTypeCategory == Type::Category::Enum)
// just clean
convertType(_typeOnStack, *_typeOnStack.mobileType(), true);
else
{
solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Contract, "");
IntegerType addressType(0, IntegerType::Modifier::Address);
IntegerType const& targetType = targetTypeCategory == Type::Category::Integer
? dynamic_cast<IntegerType const&>(_targetType) : addressType;
if (stackTypeCategory == Type::Category::IntegerConstant)
{
IntegerConstantType const& constType = dynamic_cast<IntegerConstantType const&>(_typeOnStack);
// We know that the stack is clean, we only have to clean for a narrowing conversion
// where cleanup is forced.
if (targetType.getNumBits() < constType.getIntegerType()->getNumBits() && _cleanupNeeded)
cleanHigherOrderBits(targetType);
}
else
{
IntegerType const& typeOnStack = stackTypeCategory == Type::Category::Integer
? dynamic_cast<IntegerType const&>(_typeOnStack) : addressType;
// Widening: clean up according to source type width
// Non-widening and force: clean up according to target type bits
if (targetType.getNumBits() > typeOnStack.getNumBits())
cleanHigherOrderBits(typeOnStack);
else if (_cleanupNeeded)
cleanHigherOrderBits(targetType);
}
}
break;
case Type::Category::Array:
{
solAssert(targetTypeCategory == stackTypeCategory, "");
ArrayType const& typeOnStack = dynamic_cast<ArrayType const&>(_typeOnStack);
ArrayType const& targetType = dynamic_cast<ArrayType const&>(_targetType);
switch (targetType.location())
{
case ReferenceType::Location::Storage:
// Other cases are done explicitly in LValue::storeValue, and only possible by assignment.
solAssert(
targetType.isPointer() &&
typeOnStack.location() == ReferenceType::Location::Storage,
"Invalid conversion to storage type."
);
break;
case ReferenceType::Location::Memory:
{
// Copy the array to a free position in memory, unless it is already in memory.
if (typeOnStack.location() != ReferenceType::Location::Memory)
{
// stack: <source ref> (variably sized)
unsigned stackSize = typeOnStack.getSizeOnStack();
fetchFreeMemoryPointer();
moveIntoStack(stackSize);
// stack: <mem start> <source ref> (variably sized)
if (targetType.isDynamicallySized())
{
bool fromStorage = (typeOnStack.location() == ReferenceType::Location::Storage);
// store length
if (fromStorage)
{
stackSize--;
// remove storage offset, as requested by ArrayUtils::retrieveLength
m_context << eth::Instruction::POP;
}
ArrayUtils(m_context).retrieveLength(typeOnStack);
// Stack: <mem start> <source ref> <length>
m_context << eth::dupInstruction(2 + stackSize) << eth::Instruction::MSTORE;
m_context << eth::dupInstruction(1 + stackSize) << u256(0x20);
m_context << eth::Instruction::ADD;
moveIntoStack(stackSize);
if (fromStorage)
{
m_context << u256(0);
stackSize++;
}
}
else
{
m_context << eth::dupInstruction(1 + stackSize);
moveIntoStack(stackSize);
}
// Stack: <mem start> <mem data start> <value>
// Store data part.
storeInMemoryDynamic(typeOnStack);
// Stack <mem start> <mem end>
storeFreeMemoryPointer();
}
else if (typeOnStack.location() == ReferenceType::Location::CallData)
{
// Stack: <offset> <length>
//@todo
solAssert(false, "Not yet implemented.");
}
// nothing to do for memory to memory
break;
}
default:
solAssert(false, "Invalid type conversion requested.");
}
break;
}
case Type::Category::Struct:
{
//@todo we can probably use some of the code for arrays here.
solAssert(targetTypeCategory == stackTypeCategory, "");
auto& targetType = dynamic_cast<StructType const&>(_targetType);
auto& stackType = dynamic_cast<StructType const&>(_typeOnStack);
solAssert(
targetType.location() == ReferenceType::Location::Storage &&
stackType.location() == ReferenceType::Location::Storage,
"Non-storage structs not yet implemented."
);
solAssert(
targetType.isPointer(),
"Type conversion to non-pointer struct requested."
);
break;
}
default:
// All other types should not be convertible to non-equal types.
solAssert(_typeOnStack == _targetType, "Invalid type conversion requested.");
break;
}
}
void CompilerUtils::moveToStackVariable(VariableDeclaration const& _variable)
{
unsigned const stackPosition = m_context.baseToCurrentStackOffset(m_context.getBaseStackOffsetOfVariable(_variable));
unsigned const size = _variable.getType()->getSizeOnStack();
solAssert(stackPosition >= size, "Variable size and position mismatch.");
// move variable starting from its top end in the stack
if (stackPosition - size + 1 > 16)
BOOST_THROW_EXCEPTION(
CompilerError() <<
errinfo_sourceLocation(_variable.getLocation()) <<
errinfo_comment("Stack too deep, try removing local variables.")
);
for (unsigned i = 0; i < size; ++i)
m_context << eth::swapInstruction(stackPosition - size + 1) << eth::Instruction::POP;
}
void CompilerUtils::copyToStackTop(unsigned _stackDepth, unsigned _itemSize)
{
solAssert(_stackDepth <= 16, "Stack too deep, try removing local variables.");
for (unsigned i = 0; i < _itemSize; ++i)
m_context << eth::dupInstruction(_stackDepth);
}
void CompilerUtils::moveToStackTop(unsigned _stackDepth)
{
solAssert(_stackDepth <= 15, "Stack too deep, try removing local variables.");
for (unsigned i = 0; i < _stackDepth; ++i)
m_context << eth::swapInstruction(1 + i);
}
void CompilerUtils::moveIntoStack(unsigned _stackDepth)
{
solAssert(_stackDepth <= 16, "Stack too deep, try removing local variables.");
for (unsigned i = _stackDepth; i > 0; --i)
m_context << eth::swapInstruction(i);
}
void CompilerUtils::popStackElement(Type const& _type)
{
popStackSlots(_type.getSizeOnStack());
}
void CompilerUtils::popStackSlots(size_t _amount)
{
for (size_t i = 0; i < _amount; ++i)
m_context << eth::Instruction::POP;
}
unsigned CompilerUtils::getSizeOnStack(vector<shared_ptr<Type const>> const& _variableTypes)
{
unsigned size = 0;
for (shared_ptr<Type const> const& type: _variableTypes)
size += type->getSizeOnStack();
return size;
}
void CompilerUtils::computeHashStatic(Type const& _type, bool _padToWordBoundaries)
{
unsigned length = storeInMemory(0, _type, _padToWordBoundaries);
solAssert(length <= CompilerUtils::freeMemoryPointer, "");
m_context << u256(length) << u256(0) << eth::Instruction::SHA3;
}
unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries)
{
unsigned numBytes = _type.getCalldataEncodedSize(_padToWordBoundaries);
bool leftAligned = _type.getCategory() == Type::Category::FixedBytes;
if (numBytes == 0)
m_context << eth::Instruction::POP << u256(0);
else
{
solAssert(numBytes <= 32, "Static memory load of more than 32 bytes requested.");
m_context << (_fromCalldata ? eth::Instruction::CALLDATALOAD : eth::Instruction::MLOAD);
if (numBytes != 32)
{
// add leading or trailing zeros by dividing/multiplying depending on alignment
u256 shiftFactor = u256(1) << ((32 - numBytes) * 8);
m_context << shiftFactor << eth::Instruction::SWAP1 << eth::Instruction::DIV;
if (leftAligned)
m_context << shiftFactor << eth::Instruction::MUL;
}
}
return numBytes;
}
void CompilerUtils::cleanHigherOrderBits(IntegerType const& _typeOnStack)
{
if (_typeOnStack.getNumBits() == 256)
return;
else if (_typeOnStack.isSigned())
m_context << u256(_typeOnStack.getNumBits() / 8 - 1) << eth::Instruction::SIGNEXTEND;
else
m_context << ((u256(1) << _typeOnStack.getNumBits()) - 1) << eth::Instruction::AND;
}
unsigned CompilerUtils::prepareMemoryStore(Type const& _type, bool _padToWordBoundaries) const
{
unsigned numBytes = _type.getCalldataEncodedSize(_padToWordBoundaries);
bool leftAligned = _type.getCategory() == Type::Category::FixedBytes;
if (numBytes == 0)
m_context << eth::Instruction::POP;
else
{
solAssert(numBytes <= 32, "Memory store of more than 32 bytes requested.");
if (numBytes != 32 && !leftAligned && !_padToWordBoundaries)
// shift the value accordingly before storing
m_context << (u256(1) << ((32 - numBytes) * 8)) << eth::Instruction::MUL;
}
return numBytes;
}
}
}
