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Count gas for additional memory

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[#79942174]
This commit is contained in:
Paweł Bylica 2014-10-13 10:57:12 +02:00
parent d6e6a5f558
commit 5470faf9ec
5 changed files with 31 additions and 10 deletions
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4
evmcc/Compiler.cpp
View file

@ -196,9 +196,9 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
createBasicBlocks(bytecode);
// Init runtime structures.
auto memory = Memory(builder, module.get());
auto ext = Ext(builder, module.get());
GasMeter gasMeter(builder, module.get());
Memory memory(builder, module.get(), gasMeter);
Ext ext(builder, module.get());
// Jump to first instruction
builder.CreateBr(basicBlocks.begin()->second);

7
evmcc/GasMeter.cpp
View file

@ -114,4 +114,11 @@ void GasMeter::check(Instruction _inst)
}
}
void GasMeter::checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder)
{
// Memory uses other builder, but that can be changes later
auto cost = _builder.CreateMul(_additionalMemoryInWords, _builder.getIntN(256, static_cast<uint64_t>(c_memoryGas)), "memcost");
_builder.CreateCall(m_gasCheckFunc, cost);
}
}

3
evmcc/GasMeter.h
View file

@ -18,6 +18,9 @@ public:
void check(dev::eth::Instruction _inst);
/// Generate code that checks the cost of additional memory used by program
void checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder);
private:
/// Cumulative gas cost of a block of instructions
/// @TODO Handle overflow

22
evmcc/Memory.cpp
View file

@ -13,6 +13,7 @@
#include "Type.h"
#include "Runtime.h"
#include "GasMeter.h"
#ifdef _MSC_VER
#define EXPORT __declspec(dllexport)
@ -23,8 +24,8 @@
namespace evmcc
{
Memory::Memory(llvm::IRBuilder<>& _builder, llvm::Module* _module)
: m_builder(_builder)
Memory::Memory(llvm::IRBuilder<>& _builder, llvm::Module* _module, GasMeter& _gasMeter):
m_builder(_builder)
{
auto voidTy = m_builder.getVoidTy();
auto i64Ty = m_builder.getInt64Ty();
@ -51,12 +52,12 @@ Memory::Memory(llvm::IRBuilder<>& _builder, llvm::Module* _module)
m_size->setUnnamedAddr(true); // Address is not important
m_resize = llvm::Function::Create(llvm::FunctionType::get(Type::BytePtr, Type::WordPtr, false), llvm::Function::ExternalLinkage, "mem_resize", _module);
m_loadWord = createFunc(false, Type::i256, _module);
m_storeWord = createFunc(true, Type::i256, _module);
m_storeByte = createFunc(true, Type::Byte, _module);
m_loadWord = createFunc(false, Type::i256, _module, _gasMeter);
m_storeWord = createFunc(true, Type::i256, _module, _gasMeter);
m_storeByte = createFunc(true, Type::Byte, _module, _gasMeter);
}
llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::Module* _module)
llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::Module* _module, GasMeter& _gasMeter)
{
auto isWord = _valueType == Type::i256;
@ -69,6 +70,7 @@ llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::
auto resizeBB = llvm::BasicBlock::Create(func->getContext(), "resize", func);
auto accessBB = llvm::BasicBlock::Create(func->getContext(), "access", func);
// BB "check"
llvm::IRBuilder<> builder(checkBB);
llvm::Value* index = func->arg_begin();
index->setName("index");
@ -78,12 +80,20 @@ llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::
auto resizeNeeded = builder.CreateICmpULE(size, sizeRequired, "resizeNeeded");
builder.CreateCondBr(resizeNeeded, resizeBB, accessBB); // OPT branch weights?
// BB "resize"
builder.SetInsertPoint(resizeBB);
// Check gas first
auto wordsRequired = builder.CreateUDiv(builder.CreateAdd(sizeRequired, builder.getIntN(256, 31)), builder.getIntN(256, 32), "wordsRequired");
auto words = builder.CreateUDiv(builder.CreateAdd(size, builder.getIntN(256, 31)), builder.getIntN(256, 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(accessBB);
// BB "access"
builder.SetInsertPoint(accessBB);
auto data = builder.CreateLoad(m_data, "data");
auto ptr = builder.CreateGEP(data, index, "ptr");

5
evmcc/Memory.h
View file

@ -6,11 +6,12 @@
namespace evmcc
{
class GasMeter;
class Memory
{
public:
Memory(llvm::IRBuilder<>& _builder, llvm::Module* _module);
Memory(llvm::IRBuilder<>& _builder, llvm::Module* _module, GasMeter& _gasMeter);
Memory(const Memory&) = delete;
void operator=(Memory) = delete;
@ -22,7 +23,7 @@ public:
void dump(uint64_t _begin, uint64_t _end = 0);
private:
llvm::Function* createFunc(bool _isStore, llvm::Type* _type, llvm::Module* _module);
llvm::Function* createFunc(bool _isStore, llvm::Type* _type, llvm::Module* _module, GasMeter& _gasMeter);
private:
llvm::IRBuilder<>& m_builder;