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Private mem.require function that preallocates memory and counts gas fee

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This commit is contained in:
Paweł Bylica 2014-10-14 15:12:11 +02:00
parent 01ca987093
commit ab556c638a
2 changed files with 48 additions and 2 deletions
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46
evmcc/Memory.cpp
View file

@ -43,6 +43,43 @@ Memory::Memory(llvm::IRBuilder<>& _builder, llvm::Module* _module, GasMeter& _ga
m_loadWord = createFunc(false, Type::i256, _module, _gasMeter);
m_storeWord = createFunc(true, Type::i256, _module, _gasMeter);
m_storeByte = createFunc(true, Type::Byte, _module, _gasMeter);
m_require = createRequireFunc(_module, _gasMeter);
}
llvm::Function* Memory::createRequireFunc(llvm::Module* _module, GasMeter& _gasMeter)
{
auto func = llvm::Function::Create(llvm::FunctionType::get(Type::Void, Type::i256, false), llvm::Function::PrivateLinkage, "mem.require", _module);
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);
// BB "check"
llvm::IRBuilder<> builder(checkBB);
llvm::Value* sizeRequired = func->arg_begin();
sizeRequired->setName("sizeRequired");
auto size = builder.CreateLoad(m_size, "size");
auto resizeNeeded = builder.CreateICmpULE(size, sizeRequired, "resizeNeeded");
builder.CreateCondBr(resizeNeeded, resizeBB, returnBB); // OPT branch weights?
// BB "resize"
builder.SetInsertPoint(resizeBB);
// Check gas first
auto wordsRequired = builder.CreateUDiv(builder.CreateAdd(sizeRequired, Constant::get(31)), Constant::get(32), "wordsRequired");
auto words = builder.CreateUDiv(builder.CreateAdd(size, Constant::get(31)), Constant::get(32), "words");
auto newWords = builder.CreateSub(wordsRequired, words, "addtionalWords");
_gasMeter.checkMemory(newWords, builder);
// Resize
builder.CreateStore(sizeRequired, m_size);
auto newData = builder.CreateCall(m_resize, m_size, "newData");
builder.CreateStore(newData, m_data);
builder.CreateBr(returnBB);
// BB "return"
builder.SetInsertPoint(returnBB);
builder.CreateRetVoid();
return func;
}
llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::Module* _module, GasMeter& _gasMeter)
@ -131,10 +168,15 @@ llvm::Value* Memory::getSize()
return m_builder.CreateLoad(m_size);
}
void Memory::require(llvm::Value* _size)
{
m_builder.CreateCall(m_require, _size);
}
void Memory::registerReturnData(llvm::Value* _index, llvm::Value* _size)
{
auto lastWord = m_builder.CreateAdd(_index, m_builder.CreateSub(_size, Constant::get(32)), "lastWord");
loadWord(lastWord); // Make sure that memory is allocated and count gas
auto sizeRequired = m_builder.CreateAdd(_index, _size, "sizeRequired");
require(sizeRequired); // Make sure that memory is allocated and count gas
m_builder.CreateStore(_index, m_returnDataOffset);
m_builder.CreateStore(_size, m_returnDataSize);

4
evmcc/Memory.h
View file

@ -20,6 +20,8 @@ public:
void storeByte(llvm::Value* _addr, llvm::Value* _byte);
llvm::Value* getSize();
void require(llvm::Value* _size);
void registerReturnData(llvm::Value* _index, llvm::Value* _size);
static dev::bytesConstRef getReturnData();
@ -27,6 +29,7 @@ public:
private:
llvm::Function* createFunc(bool _isStore, llvm::Type* _type, llvm::Module* _module, GasMeter& _gasMeter);
llvm::Function* createRequireFunc(llvm::Module* _module, GasMeter& _gasMeter);
private:
llvm::IRBuilder<>& m_builder;
@ -41,6 +44,7 @@ private:
llvm::Function* m_loadWord;
llvm::Function* m_storeWord;
llvm::Function* m_storeByte;
llvm::Function* m_require;
llvm::Function* m_resize;
llvm::Function* m_memDump;