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Generate gas checking function

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This commit is contained in:
Paweł Bylica 2014-10-09 15:44:41 +02:00
parent 97644d660a
commit 04cf0cfcea
4 changed files with 17 additions and 4 deletions
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16
evmcc/GasMeter.cpp
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@ -57,15 +57,23 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, llvm::Module* _module):
m_gas = new llvm::GlobalVariable(*_module, Type::i256, false, llvm::GlobalVariable::PrivateLinkage, llvm::UndefValue::get(Type::i256), "gas"); m_gas = new llvm::GlobalVariable(*_module, Type::i256, false, llvm::GlobalVariable::PrivateLinkage, llvm::UndefValue::get(Type::i256), "gas");
m_gas->setUnnamedAddr(true); // Address is not important m_gas->setUnnamedAddr(true); // Address is not important
//llvm::Function::Create() auto pt = m_builder.GetInsertPoint();
auto bb = m_builder.GetInsertBlock();
m_gasCheckFunc = llvm::Function::Create(llvm::FunctionType::get(Type::Void, Type::i256, false), llvm::Function::PrivateLinkage, "gas.check", _module);
auto gasCheckBB = llvm::BasicBlock::Create(_builder.getContext(), {}, m_gasCheckFunc);
m_builder.SetInsertPoint(gasCheckBB);
llvm::Value* cost = m_gasCheckFunc->arg_begin();
llvm::Value* gas = m_builder.CreateLoad(m_gas);
gas = m_builder.CreateSub(gas, cost);
m_builder.CreateStore(gas, m_gas);
m_builder.CreateRetVoid();
m_builder.SetInsertPoint(bb, pt);
} }
void GasMeter::check(Instruction _inst) void GasMeter::check(Instruction _inst)
{ {
auto stepCost = getStepCost(_inst); auto stepCost = getStepCost(_inst);
auto before = m_builder.CreateLoad(m_gas, "gas.before"); m_builder.CreateCall(m_gasCheckFunc, m_builder.getIntN(256, stepCost));
auto after = m_builder.CreateSub(before, m_builder.getIntN(256, stepCost));
m_builder.CreateStore(after, m_gas);
} }
} }

1
evmcc/GasMeter.h
View file

@ -21,6 +21,7 @@ public:
private: private:
llvm::IRBuilder<>& m_builder; llvm::IRBuilder<>& m_builder;
llvm::GlobalVariable* m_gas; llvm::GlobalVariable* m_gas;
llvm::Function* m_gasCheckFunc;
}; };
} }

2
evmcc/Type.cpp
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@ -8,11 +8,13 @@ namespace evmcc
llvm::Type* Type::i256; llvm::Type* Type::i256;
llvm::Type* Type::lowPrecision; llvm::Type* Type::lowPrecision;
llvm::Type* Type::Void;
void Type::init(llvm::LLVMContext& _context) void Type::init(llvm::LLVMContext& _context)
{ {
i256 = llvm::Type::getIntNTy(_context, 256); i256 = llvm::Type::getIntNTy(_context, 256);
lowPrecision = llvm::Type::getInt64Ty(_context); lowPrecision = llvm::Type::getInt64Ty(_context);
Void = llvm::Type::getVoidTy(_context);
} }
} }

2
evmcc/Type.h
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@ -14,6 +14,8 @@ struct Type
/// @TODO: Use 64-bit for now. In 128-bit compiler-rt library functions are required /// @TODO: Use 64-bit for now. In 128-bit compiler-rt library functions are required
static llvm::Type* lowPrecision; static llvm::Type* lowPrecision;
static llvm::Type* Void;
static void init(llvm::LLVMContext& _context); static void init(llvm::LLVMContext& _context);
}; };