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InsertPointGuard helper class for IRBuilder

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This commit is contained in:
Paweł Bylica 2014-10-14 16:11:39 +02:00
parent 82cba7a346
commit 9d9e1600a3
4 changed files with 46 additions and 27 deletions
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8
evmcc/GasMeter.cpp
View file

@ -8,6 +8,7 @@
#include <libevm/FeeStructure.h>
#include "Type.h"
#include "Utils.h"
namespace evmcc
{
@ -81,17 +82,14 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, llvm::Module* _module):
m_gas = new llvm::GlobalVariable(*_module, Type::i256, false, llvm::GlobalVariable::ExternalLinkage, nullptr, "gas");
m_gas->setUnnamedAddr(true); // Address is not important
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);
InsertPointGuard guard(m_builder);
m_builder.SetInsertPoint(llvm::BasicBlock::Create(_builder.getContext(), {}, m_gasCheckFunc));
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::count(Instruction _inst)

37
evmcc/Memory.cpp
View file

@ -54,30 +54,32 @@ llvm::Function* Memory::createRequireFunc(llvm::Module* _module, GasMeter& _gasM
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 "check"
llvm::IRBuilder<> builder(checkBB);
m_builder.SetInsertPoint(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?
auto size = m_builder.CreateLoad(m_size, "size");
auto resizeNeeded = m_builder.CreateICmpULE(size, sizeRequired, "resizeNeeded");
m_builder.CreateCondBr(resizeNeeded, resizeBB, returnBB); // OPT branch weights?
// BB "resize"
builder.SetInsertPoint(resizeBB);
m_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);
auto wordsRequired = m_builder.CreateUDiv(m_builder.CreateAdd(sizeRequired, Constant::get(31)), Constant::get(32), "wordsRequired");
auto words = m_builder.CreateUDiv(m_builder.CreateAdd(size, Constant::get(31)), Constant::get(32), "words");
auto newWords = m_builder.CreateSub(wordsRequired, words, "addtionalWords");
_gasMeter.checkMemory(newWords, m_builder);
// Resize
builder.CreateStore(sizeRequired, m_size);
auto newData = builder.CreateCall(m_resize, m_size, "newData");
builder.CreateStore(newData, m_data);
builder.CreateBr(returnBB);
m_builder.CreateStore(sizeRequired, m_size);
auto newData = m_builder.CreateCall(m_resize, m_size, "newData");
m_builder.CreateStore(newData, m_data);
m_builder.CreateBr(returnBB);
// BB "return"
builder.SetInsertPoint(returnBB);
builder.CreateRetVoid();
m_builder.SetInsertPoint(returnBB);
m_builder.CreateRetVoid();
return func;
}
@ -90,8 +92,7 @@ llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::
auto funcType = _isStore ? llvm::FunctionType::get(Type::Void, storeArgs, false) : llvm::FunctionType::get(Type::i256, Type::i256, false);
auto func = llvm::Function::Create(funcType, llvm::Function::PrivateLinkage, name, _module);
auto origBB = m_builder.GetInsertBlock();
auto origPt = m_builder.GetInsertPoint();
InsertPointGuard guard(m_builder); // Restores insert point at function exit
m_builder.SetInsertPoint(llvm::BasicBlock::Create(func->getContext(), {}, func));
llvm::Value* index = func->arg_begin();
@ -116,8 +117,6 @@ llvm::Function* Memory::createFunc(bool _isStore, llvm::Type* _valueType, llvm::
m_builder.CreateRet(ret);
}
m_builder.SetInsertPoint(origBB, origPt);
return func;
}

4
evmcc/Memory.h
View file

@ -45,11 +45,11 @@ private:
llvm::GlobalVariable* m_returnDataOffset;
llvm::GlobalVariable* m_returnDataSize;
llvm::Function* m_resize;
llvm::Function* m_require;
llvm::Function* m_loadWord;
llvm::Function* m_storeWord;
llvm::Function* m_storeByte;
llvm::Function* m_require;
llvm::Function* m_resize;
llvm::Function* m_memDump;
};

24
evmcc/Utils.h
View file

@ -1,7 +1,7 @@
#pragma once
#include <cstdint>
#include <llvm/IR/IRBuilder.h>
#include <libdevcore/Common.h>
@ -22,4 +22,26 @@ static_assert(sizeof(i256) == 32, "Wrong i265 size");
dev::u256 llvm2eth(i256);
i256 eth2llvm(dev::u256);
struct InsertPointGuard
{
InsertPointGuard(llvm::IRBuilder<>& _builder) :
m_builder(_builder),
m_insertBB(m_builder.GetInsertBlock()),
m_insertPt(m_builder.GetInsertPoint())
{}
~InsertPointGuard()
{
m_builder.SetInsertPoint(m_insertBB, m_insertPt);
}
private:
llvm::IRBuilder<>& m_builder;
llvm::BasicBlock* m_insertBB;
llvm::BasicBlock::iterator m_insertPt;
InsertPointGuard(const InsertPointGuard&) = delete;
void operator=(InsertPointGuard) = delete;
};
}