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Memory.cpp
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#include "Memory.h"
#include "preprocessor/llvm_includes_start.h"
#include <llvm/IR/IntrinsicInst.h>
#include "preprocessor/llvm_includes_end.h"
#include "Type.h"
#include "Runtime.h"
#include "GasMeter.h"
#include "Endianness.h"
#include "RuntimeManager.h"
namespace dev
{
namespace eth
{
namespace jit
{
Memory::Memory(RuntimeManager& _runtimeManager, GasMeter& _gasMeter):
RuntimeHelper(_runtimeManager), // TODO: RuntimeHelper not needed
m_memory{getBuilder(), _runtimeManager.getMem()},
m_gasMeter(_gasMeter)
{}
llvm::Function* Memory::getRequireFunc()
{
auto& func = m_require;
if (!func)
{
llvm::Type* argTypes[] = {Array::getType()->getPointerTo(), Type::Word, Type::Word, Type::BytePtr, Type::GasPtr};
func = llvm::Function::Create(llvm::FunctionType::get(Type::Void, argTypes, false), llvm::Function::PrivateLinkage, "mem.require", getModule());
func->setDoesNotThrow();
auto mem = &func->getArgumentList().front();
mem->setName("mem");
auto blkOffset = mem->getNextNode();
blkOffset->setName("blkOffset");
auto blkSize = blkOffset->getNextNode();
blkSize->setName("blkSize");
auto jmpBuf = blkSize->getNextNode();
jmpBuf->setName("jmpBuf");
auto gas = jmpBuf->getNextNode();
gas->setName("gas");
auto preBB = llvm::BasicBlock::Create(func->getContext(), "Pre", func);
auto checkBB = llvm::BasicBlock::Create(func->getContext(), "Check", func);
auto resizeBB = llvm::BasicBlock::Create(func->getContext(), "Resize", func);
auto returnBB = llvm::BasicBlock::Create(func->getContext(), "Return", func);
InsertPointGuard guard(m_builder); // Restores insert point at function exit
// BB "Pre": Ignore checks with size 0
m_builder.SetInsertPoint(preBB);
m_builder.CreateCondBr(m_builder.CreateICmpNE(blkSize, Constant::get(0)), checkBB, returnBB, Type::expectTrue);
// BB "Check"
m_builder.SetInsertPoint(checkBB);
static const auto c_inputMax = uint64_t(1) << 33; // max value of blkSize and blkOffset that will not result in integer overflow in calculations below
auto blkOffsetOk = m_builder.CreateICmpULE(blkOffset, Constant::get(c_inputMax), "blkOffsetOk");
auto blkO = m_builder.CreateSelect(blkOffsetOk, m_builder.CreateTrunc(blkOffset, Type::Size), m_builder.getInt64(c_inputMax), "bklO");
auto blkSizeOk = m_builder.CreateICmpULE(blkSize, Constant::get(c_inputMax), "blkSizeOk");
auto blkS = m_builder.CreateSelect(blkSizeOk, m_builder.CreateTrunc(blkSize, Type::Size), m_builder.getInt64(c_inputMax), "bklS");
auto sizeReq0 = m_builder.CreateNUWAdd(blkO, blkS, "sizeReq0");
auto sizeReq = m_builder.CreateAnd(m_builder.CreateNUWAdd(sizeReq0, m_builder.getInt64(31)), uint64_t(-1) << 5, "sizeReq"); // s' = ((s0 + 31) / 32) * 32
auto sizeCur = m_memory.size(mem);
auto sizeOk = m_builder.CreateICmpULE(sizeReq, sizeCur, "sizeOk");
m_builder.CreateCondBr(sizeOk, returnBB, resizeBB, Type::expectTrue);
// BB "Resize"
m_builder.SetInsertPoint(resizeBB);
// Check gas first
auto w1 = m_builder.CreateLShr(sizeReq, 5);
auto w1s = m_builder.CreateNUWMul(w1, w1);
auto c1 = m_builder.CreateAdd(m_builder.CreateNUWMul(w1, m_builder.getInt64(3)), m_builder.CreateLShr(w1s, 9));
auto w0 = m_builder.CreateLShr(sizeCur, 5);
auto w0s = m_builder.CreateNUWMul(w0, w0);
auto c0 = m_builder.CreateAdd(m_builder.CreateNUWMul(w0, m_builder.getInt64(3)), m_builder.CreateLShr(w0s, 9));
auto cc = m_builder.CreateNUWSub(c1, c0);
auto costOk = m_builder.CreateAnd(blkOffsetOk, blkSizeOk, "costOk");
auto c = m_builder.CreateSelect(costOk, cc, m_builder.getInt64(std::numeric_limits<int64_t>::max()), "c");
m_gasMeter.count(c, jmpBuf, gas);
// Resize
m_memory.extend(mem, sizeReq);
m_builder.CreateBr(returnBB);
// BB "Return"
m_builder.SetInsertPoint(returnBB);
m_builder.CreateRetVoid();
}
return func;
}
llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType)
{
auto isWord = _valueType == Type::Word;
llvm::Type* storeArgs[] = {Array::getType()->getPointerTo(), Type::Word, _valueType};
llvm::Type* loadArgs[] = {Array::getType()->getPointerTo(), Type::Word};
auto name = _isStore ? isWord ? "mstore" : "mstore8" : "mload";
auto funcType = _isStore ? llvm::FunctionType::get(Type::Void, storeArgs, false) : llvm::FunctionType::get(Type::Word, loadArgs, false);
auto func = llvm::Function::Create(funcType, llvm::Function::PrivateLinkage, name, getModule());
InsertPointGuard guard(m_builder); // Restores insert point at function exit
m_builder.SetInsertPoint(llvm::BasicBlock::Create(func->getContext(), {}, func));
auto mem = &func->getArgumentList().front();
mem->setName("mem");
auto index = mem->getNextNode();
index->setName("index");
if (_isStore)
{
auto valueArg = index->getNextNode();
valueArg->setName("value");
auto value = isWord ? Endianness::toBE(m_builder, valueArg) : valueArg;
auto memPtr = m_memory.getPtr(mem, m_builder.CreateTrunc(index, Type::Size));
auto valuePtr = m_builder.CreateBitCast(memPtr, _valueType->getPointerTo(), "valuePtr");
m_builder.CreateStore(value, valuePtr);
m_builder.CreateRetVoid();
}
else
{
auto memPtr = m_memory.getPtr(mem, m_builder.CreateTrunc(index, Type::Size));
llvm::Value* ret = m_builder.CreateLoad(memPtr);
ret = Endianness::toNative(m_builder, ret);
m_builder.CreateRet(ret);
}
return func;
}
llvm::Function* Memory::getLoadWordFunc()
{
auto& func = m_loadWord;
if (!func)
func = createFunc(false, Type::Word);
return func;
}
llvm::Function* Memory::getStoreWordFunc()
{
auto& func = m_storeWord;
if (!func)
func = createFunc(true, Type::Word);
return func;
}
llvm::Function* Memory::getStoreByteFunc()
{
auto& func = m_storeByte;
if (!func)
func = createFunc(true, Type::Byte);
return func;
}
llvm::Value* Memory::loadWord(llvm::Value* _addr)
{
require(_addr, Constant::get(Type::Word->getPrimitiveSizeInBits() / 8));
return createCall(getLoadWordFunc(), {getRuntimeManager().getMem(), _addr});
}
void Memory::storeWord(llvm::Value* _addr, llvm::Value* _word)
{
require(_addr, Constant::get(Type::Word->getPrimitiveSizeInBits() / 8));
createCall(getStoreWordFunc(), {getRuntimeManager().getMem(), _addr, _word});
}
void Memory::storeByte(llvm::Value* _addr, llvm::Value* _word)
{
require(_addr, Constant::get(Type::Byte->getPrimitiveSizeInBits() / 8));
auto byte = m_builder.CreateTrunc(_word, Type::Byte, "byte");
createCall(getStoreByteFunc(), {getRuntimeManager().getMem(), _addr, byte});
}
llvm::Value* Memory::getData()
{
auto memPtr = m_builder.CreateBitCast(getRuntimeManager().getMem(), Type::BytePtr->getPointerTo());
auto data = m_builder.CreateLoad(memPtr, "data");
assert(data->getType() == Type::BytePtr);
return data;
}
llvm::Value* Memory::getSize()
{
return m_builder.CreateZExt(m_memory.size(), Type::Word, "msize"); // TODO: Allow placing i64 on stack
}
llvm::Value* Memory::getBytePtr(llvm::Value* _index)
{
auto idx = m_builder.CreateTrunc(_index, Type::Size, "idx"); // Never allow memory index be a type bigger than i64
return m_builder.CreateGEP(getData(), idx, "ptr");
}
void Memory::require(llvm::Value* _offset, llvm::Value* _size)
{
if (auto constant = llvm::dyn_cast<llvm::ConstantInt>(_size))
{
if (!constant->getValue())
return;
}
createCall(getRequireFunc(), {getRuntimeManager().getMem(), _offset, _size, getRuntimeManager().getJmpBuf(), getRuntimeManager().getGasPtr()});
}
void Memory::copyBytes(llvm::Value* _srcPtr, llvm::Value* _srcSize, llvm::Value* _srcIdx,
llvm::Value* _destMemIdx, llvm::Value* _reqBytes)
{
require(_destMemIdx, _reqBytes);
// Additional copy cost
// TODO: This round ups to 32 happens in many places
auto reqBytes = m_builder.CreateTrunc(_reqBytes, Type::Gas);
auto copyWords = m_builder.CreateUDiv(m_builder.CreateNUWAdd(reqBytes, m_builder.getInt64(31)), m_builder.getInt64(32));
m_gasMeter.countCopy(copyWords);
// Algorithm:
// isOutsideData = idx256 >= size256
// idx64 = trunc idx256
// size64 = trunc size256
// dataLeftSize = size64 - idx64 // safe if not isOutsideData
// reqBytes64 = trunc _reqBytes // require() handles large values
// bytesToCopy0 = select(reqBytes64 > dataLeftSize, dataSizeLeft, reqBytes64) // min
// bytesToCopy = select(isOutsideData, 0, bytesToCopy0)
auto isOutsideData = m_builder.CreateICmpUGE(_srcIdx, _srcSize);
auto idx64 = m_builder.CreateTrunc(_srcIdx, Type::Size);
auto size64 = m_builder.CreateTrunc(_srcSize, Type::Size);
auto dataLeftSize = m_builder.CreateNUWSub(size64, idx64);
auto outOfBound = m_builder.CreateICmpUGT(reqBytes, dataLeftSize);
auto bytesToCopyInner = m_builder.CreateSelect(outOfBound, dataLeftSize, reqBytes);
auto bytesToCopy = m_builder.CreateSelect(isOutsideData, m_builder.getInt64(0), bytesToCopyInner, "bytesToCopy");
auto bytesToZero = m_builder.CreateNUWSub(reqBytes, bytesToCopy, "bytesToZero");
auto src = m_builder.CreateGEP(_srcPtr, idx64, "src");
auto dstIdx = m_builder.CreateTrunc(_destMemIdx, Type::Size, "dstIdx"); // Never allow memory index be a type bigger than i64
auto padIdx = m_builder.CreateNUWAdd(dstIdx, bytesToCopy, "padIdx");
auto dst = m_memory.getPtr(getRuntimeManager().getMem(), dstIdx);
auto pad = m_memory.getPtr(getRuntimeManager().getMem(), padIdx);
m_builder.CreateMemCpy(dst, src, bytesToCopy, 0);
m_builder.CreateMemSet(pad, m_builder.getInt8(0), bytesToZero, 0);
}
}
}
}