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#include "Compiler.h"
#include <boost/dynamic_bitset.hpp>
#include <llvm/IR/IRBuilder.h>
#include <llvm/IR/CFG.h>
#include <libevmface/Instruction.h>
#include "Type.h"
#include "Memory.h"
#include "Ext.h"
#include "GasMeter.h"
namespace evmcc
{
using dev::eth::Instruction;
using namespace dev::eth; // We should move all the JIT code into dev::eth namespace
Compiler::Compiler()
: m_finalBlock(nullptr)
, m_badJumpBlock(nullptr)
{
Type::init(llvm::getGlobalContext());
}
void Compiler::createBasicBlocks(const dev::bytes& bytecode)
{
std::set<ProgramCounter> splitPoints; // Sorted collections of instruction indices where basic blocks start/end
splitPoints.insert(0); // First basic block
std::map<ProgramCounter, ProgramCounter> directJumpTargets;
std::vector<ProgramCounter> indirectJumpTargets;
boost::dynamic_bitset<> validJumpTargets(bytecode.size());
for (auto curr = bytecode.cbegin(); curr != bytecode.cend(); ++curr)
{
using dev::eth::Instruction;
ProgramCounter currentPC = curr - bytecode.cbegin();
validJumpTargets[currentPC] = 1;
auto inst = static_cast<Instruction>(*curr);
switch (inst)
{
case Instruction::PUSH1:
case Instruction::PUSH2:
case Instruction::PUSH3:
case Instruction::PUSH4:
case Instruction::PUSH5:
case Instruction::PUSH6:
case Instruction::PUSH7:
case Instruction::PUSH8:
case Instruction::PUSH9:
case Instruction::PUSH10:
case Instruction::PUSH11:
case Instruction::PUSH12:
case Instruction::PUSH13:
case Instruction::PUSH14:
case Instruction::PUSH15:
case Instruction::PUSH16:
case Instruction::PUSH17:
case Instruction::PUSH18:
case Instruction::PUSH19:
case Instruction::PUSH20:
case Instruction::PUSH21:
case Instruction::PUSH22:
case Instruction::PUSH23:
case Instruction::PUSH24:
case Instruction::PUSH25:
case Instruction::PUSH26:
case Instruction::PUSH27:
case Instruction::PUSH28:
case Instruction::PUSH29:
case Instruction::PUSH30:
case Instruction::PUSH31:
case Instruction::PUSH32:
{
auto numBytes = static_cast<size_t>(inst) - static_cast<size_t>(Instruction::PUSH1) + 1;
auto next = curr + numBytes + 1;
if (next >= bytecode.cend())
break;
auto nextInst = static_cast<Instruction>(*next);
if (nextInst == Instruction::JUMP || nextInst == Instruction::JUMPI)
{
// Compute target PC of the jump.
dev::u256 val = 0;
for (auto iter = curr + 1; iter < next; ++iter)
{
val <<= 8;
val |= *iter;
}
// Create a block for the JUMP target.
ProgramCounter targetPC = val.convert_to<ProgramCounter>();
if (targetPC > bytecode.size())
targetPC = bytecode.size();
splitPoints.insert(targetPC);
ProgramCounter jumpPC = (next - bytecode.cbegin());
directJumpTargets[jumpPC] = targetPC;
}
curr += numBytes;
break;
}
case Instruction::JUMPDEST:
{
// A basic block starts here.
splitPoints.insert(currentPC);
indirectJumpTargets.push_back(currentPC);
break;
}
case Instruction::JUMP:
case Instruction::JUMPI:
case Instruction::RETURN:
case Instruction::STOP:
case Instruction::SUICIDE:
{
// Create a basic block starting at the following instruction.
if (curr + 1 < bytecode.cend())
{
splitPoints.insert(currentPC + 1);
}
break;
}
default:
break;
}
}
for (auto it = splitPoints.cbegin(); it != splitPoints.cend() && *it < bytecode.size();)
{
auto beginInstIdx = *it;
++it;
auto endInstIdx = it != splitPoints.cend() ? *it : bytecode.size();
basicBlocks.emplace(std::piecewise_construct, std::forward_as_tuple(beginInstIdx), std::forward_as_tuple(beginInstIdx, endInstIdx, m_mainFunc));
}
m_finalBlock = std::make_unique<BasicBlock>("FinalBlock", m_mainFunc);
m_badJumpBlock = std::make_unique<BasicBlock>("BadJumpBlock", m_mainFunc);
m_jumpTableBlock = std::make_unique<BasicBlock>("JumpTableBlock", m_mainFunc);
for (auto it = directJumpTargets.cbegin(); it != directJumpTargets.cend(); ++it)
{
if (it->second >= bytecode.size()) // Jump out of code
{
m_directJumpTargets[it->first] = m_finalBlock.get();
}
else if (!validJumpTargets[it->second]) // Jump into data
{
std::cerr << "Bad JUMP at PC " << it->first
<< ": " << it->second << " is not a valid PC\n";
m_directJumpTargets[it->first] = m_badJumpBlock.get();
}
else
{
m_directJumpTargets[it->first] = &basicBlocks.find(it->second)->second;
}
}
for (auto it = indirectJumpTargets.cbegin(); it != indirectJumpTargets.cend(); ++it)
{
if (*it >= bytecode.size())
m_indirectJumpTargets.push_back(m_finalBlock.get());
else
m_indirectJumpTargets.push_back(&basicBlocks.find(*it)->second);
}
}
std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
{
using namespace llvm;
auto& context = getGlobalContext();
auto module = std::make_unique<Module>("main", context);
IRBuilder<> builder(context);
// Create main function
const auto i32Ty = builder.getInt32Ty();
//Type* retTypeElems[] = {i32Ty, i32Ty};
//auto retType = StructType::create(retTypeElems, "MemRef", true);
m_mainFunc = Function::Create(FunctionType::get(builder.getInt64Ty(), false), Function::ExternalLinkage, "main", module.get());
// Create the basic blocks.
auto entryBlock = llvm::BasicBlock::Create(context, "entry", m_mainFunc);
builder.SetInsertPoint(entryBlock);
createBasicBlocks(bytecode);
// Init runtime structures.
auto memory = Memory(builder, module.get());
auto ext = Ext(builder, module.get());
GasMeter gasMeter(builder, module.get());
// Jump to first instruction
builder.CreateBr(basicBlocks.begin()->second);
for (auto basicBlockPairIt = basicBlocks.begin(); basicBlockPairIt != basicBlocks.end(); ++basicBlockPairIt)
{
auto& basicBlock = basicBlockPairIt->second;
auto& stack = basicBlock.getStack();
builder.SetInsertPoint(basicBlock);
for (auto currentPC = basicBlock.begin(); currentPC != basicBlock.end(); ++currentPC)
{
auto inst = static_cast<Instruction>(bytecode[currentPC]);
gasMeter.check(inst);
switch (inst)
{
case Instruction::ADD:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto result = builder.CreateAdd(lhs, rhs);
stack.push(result);
break;
}
case Instruction::SUB:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto result = builder.CreateSub(lhs, rhs);
stack.push(result);
break;
}
case Instruction::MUL:
{
auto lhs256 = stack.pop();
auto rhs256 = stack.pop();
auto lhs128 = builder.CreateTrunc(lhs256, Type::lowPrecision);
auto rhs128 = builder.CreateTrunc(rhs256, Type::lowPrecision);
auto res128 = builder.CreateMul(lhs128, rhs128);
auto res256 = builder.CreateZExt(res128, Type::i256);
stack.push(res256);
break;
}
case Instruction::DIV:
{
auto lhs256 = stack.pop();
auto rhs256 = stack.pop();
auto lhs128 = builder.CreateTrunc(lhs256, Type::lowPrecision);
auto rhs128 = builder.CreateTrunc(rhs256, Type::lowPrecision);
auto res128 = builder.CreateUDiv(lhs128, rhs128);
auto res256 = builder.CreateZExt(res128, Type::i256);
stack.push(res256);
break;
}
case Instruction::SDIV:
{
auto lhs256 = stack.pop();
auto rhs256 = stack.pop();
auto lhs128 = builder.CreateTrunc(lhs256, Type::lowPrecision);
auto rhs128 = builder.CreateTrunc(rhs256, Type::lowPrecision);
auto res128 = builder.CreateSDiv(lhs128, rhs128);
auto res256 = builder.CreateSExt(res128, Type::i256);
stack.push(res256);
break;
}
case Instruction::MOD:
{
auto lhs256 = stack.pop();
auto rhs256 = stack.pop();
auto lhs128 = builder.CreateTrunc(lhs256, Type::lowPrecision);
auto rhs128 = builder.CreateTrunc(rhs256, Type::lowPrecision);
auto res128 = builder.CreateURem(lhs128, rhs128);
auto res256 = builder.CreateZExt(res128, Type::i256);
stack.push(res256);
break;
}
case Instruction::SMOD:
{
auto lhs256 = stack.pop();
auto rhs256 = stack.pop();
auto lhs128 = builder.CreateTrunc(lhs256, Type::lowPrecision);
auto rhs128 = builder.CreateTrunc(rhs256, Type::lowPrecision);
auto res128 = builder.CreateSRem(lhs128, rhs128);
auto res256 = builder.CreateSExt(res128, Type::i256);
stack.push(res256);
break;
}
case Instruction::EXP:
{
auto left = stack.pop();
auto right = stack.pop();
auto ret = ext.exp(left, right);
stack.push(ret);
break;
}
case Instruction::NEG:
{
auto top = stack.pop();
auto zero = ConstantInt::get(Type::i256, 0);
auto res = builder.CreateSub(zero, top);
stack.push(res);
break;
}
case Instruction::LT:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res1 = builder.CreateICmpULT(lhs, rhs);
auto res256 = builder.CreateZExt(res1, Type::i256);
stack.push(res256);
break;
}
case Instruction::GT:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res1 = builder.CreateICmpUGT(lhs, rhs);
auto res256 = builder.CreateZExt(res1, Type::i256);
stack.push(res256);
break;
}
case Instruction::SLT:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res1 = builder.CreateICmpSLT(lhs, rhs);
auto res256 = builder.CreateZExt(res1, Type::i256);
stack.push(res256);
break;
}
case Instruction::SGT:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res1 = builder.CreateICmpSGT(lhs, rhs);
auto res256 = builder.CreateZExt(res1, Type::i256);
stack.push(res256);
break;
}
case Instruction::EQ:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res1 = builder.CreateICmpEQ(lhs, rhs);
auto res256 = builder.CreateZExt(res1, Type::i256);
stack.push(res256);
break;
}
case Instruction::NOT:
{
auto top = stack.pop();
auto zero = ConstantInt::get(Type::i256, 0);
auto iszero = builder.CreateICmpEQ(top, zero, "iszero");
auto result = builder.CreateZExt(iszero, Type::i256);
stack.push(result);
break;
}
case Instruction::AND:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res = builder.CreateAnd(lhs, rhs);
stack.push(res);
break;
}
case Instruction::OR:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res = builder.CreateOr(lhs, rhs);
stack.push(res);
break;
}
case Instruction::XOR:
{
auto lhs = stack.pop();
auto rhs = stack.pop();
auto res = builder.CreateXor(lhs, rhs);
stack.push(res);
break;
}
case Instruction::BYTE:
{
const auto byteNum = stack.pop();
auto value = stack.pop();
/*
if (byteNum < 32) - use select
{
value <<= byteNum*8
value >>= 31*8
push value
}
else push 0
*/
// TODO: Shifting by 0 gives wrong results as of this bug http://llvm.org/bugs/show_bug.cgi?id=16439
auto shbits = builder.CreateShl(byteNum, builder.getIntN(256, 3));
value = builder.CreateShl(value, shbits);
value = builder.CreateLShr(value, builder.getIntN(256, 31 * 8));
auto byteNumValid = builder.CreateICmpULT(byteNum, builder.getIntN(256, 32));
value = builder.CreateSelect(byteNumValid, value, builder.getIntN(256, 0));
stack.push(value);
break;
}
case Instruction::SHA3:
{
auto inOff = stack.pop();
auto inSize = stack.pop();
auto hash = ext.sha3(inOff, inSize);
stack.push(hash);
}
case Instruction::POP:
{
stack.pop();
break;
}
case Instruction::PUSH1:
case Instruction::PUSH2:
case Instruction::PUSH3:
case Instruction::PUSH4:
case Instruction::PUSH5:
case Instruction::PUSH6:
case Instruction::PUSH7:
case Instruction::PUSH8:
case Instruction::PUSH9:
case Instruction::PUSH10:
case Instruction::PUSH11:
case Instruction::PUSH12:
case Instruction::PUSH13:
case Instruction::PUSH14:
case Instruction::PUSH15:
case Instruction::PUSH16:
case Instruction::PUSH17:
case Instruction::PUSH18:
case Instruction::PUSH19:
case Instruction::PUSH20:
case Instruction::PUSH21:
case Instruction::PUSH22:
case Instruction::PUSH23:
case Instruction::PUSH24:
case Instruction::PUSH25:
case Instruction::PUSH26:
case Instruction::PUSH27:
case Instruction::PUSH28:
case Instruction::PUSH29:
case Instruction::PUSH30:
case Instruction::PUSH31:
case Instruction::PUSH32:
{
auto numBytes = static_cast<size_t>(inst)-static_cast<size_t>(Instruction::PUSH1) + 1;
auto value = llvm::APInt(256, 0);
for (decltype(numBytes) i = 0; i < numBytes; ++i) // TODO: Use pc as iterator
{
++currentPC;
value <<= 8;
value |= bytecode[currentPC];
}
auto c = builder.getInt(value);
stack.push(c);
break;
}
case Instruction::DUP1:
case Instruction::DUP2:
case Instruction::DUP3:
case Instruction::DUP4:
case Instruction::DUP5:
case Instruction::DUP6:
case Instruction::DUP7:
case Instruction::DUP8:
case Instruction::DUP9:
case Instruction::DUP10:
case Instruction::DUP11:
case Instruction::DUP12:
case Instruction::DUP13:
case Instruction::DUP14:
case Instruction::DUP15:
case Instruction::DUP16:
{
auto index = static_cast<size_t>(inst)-static_cast<size_t>(Instruction::DUP1);
stack.dup(index);
break;
}
case Instruction::SWAP1:
case Instruction::SWAP2:
case Instruction::SWAP3:
case Instruction::SWAP4:
case Instruction::SWAP5:
case Instruction::SWAP6:
case Instruction::SWAP7:
case Instruction::SWAP8:
case Instruction::SWAP9:
case Instruction::SWAP10:
case Instruction::SWAP11:
case Instruction::SWAP12:
case Instruction::SWAP13:
case Instruction::SWAP14:
case Instruction::SWAP15:
case Instruction::SWAP16:
{
auto index = static_cast<size_t>(inst)-static_cast<size_t>(Instruction::SWAP1) + 1;
stack.swap(index);
break;
}
case Instruction::MLOAD:
{
auto addr = stack.pop();
auto word = memory.loadWord(addr);
stack.push(word);
break;
}
case Instruction::MSTORE:
{
auto addr = stack.pop();
auto word = stack.pop();
memory.storeWord(addr, word);
break;
}
case Instruction::MSTORE8:
{
auto addr = stack.pop();
auto word = stack.pop();
memory.storeByte(addr, word);
break;
}
case Instruction::MSIZE:
{
auto word = memory.getSize();
stack.push(word);
break;
}
case Instruction::SLOAD:
{
auto index = stack.pop();
auto value = ext.store(index);
stack.push(value);
break;
}
case Instruction::SSTORE:
{
auto index = stack.pop();
auto value = stack.pop();
ext.setStore(index, value);
break;
}
case Instruction::JUMP:
case Instruction::JUMPI:
{
// Generate direct jump iff:
// 1. this is not the first instruction in the block
// 2. m_directJumpTargets[currentPC] is defined (meaning that the previous instruction is a PUSH)
// Otherwise generate a indirect jump (a switch).
if (currentPC != basicBlock.begin())
{
auto pairIter = m_directJumpTargets.find(currentPC);
if (pairIter != m_directJumpTargets.end())
{
auto targetBlock = pairIter->second;
// The target address is computed at compile time,
// just pop it without looking...
stack.pop();
if (inst == Instruction::JUMP)
{
builder.CreateBr(targetBlock->llvm());
}
else // JUMPI
{
auto top = stack.pop();
auto zero = ConstantInt::get(Type::i256, 0);
auto cond = builder.CreateICmpNE(top, zero, "nonzero");
// Assume the basic blocks are properly ordered:
auto nextBBIter = basicBlockPairIt;
++nextBBIter;
assert (nextBBIter != basicBlocks.end());
auto& followBlock = nextBBIter->second;
builder.CreateCondBr(cond, targetBlock->llvm(), followBlock.llvm());
}
break;
}
}
if (inst == Instruction::JUMPI)
{
std::cerr << "Indirect JUMPI is not supported yet (at PC "
<< currentPC << ")\n";
std::exit(1);
}
builder.CreateBr(m_jumpTableBlock->llvm());
/*
// Generate switch for indirect jump.
auto dest = stack.pop();
auto switchInstr = builder.CreateSwitch(dest, m_badJumpBlock->llvm(),
m_indirectJumpTargets.size());
for (auto it = m_indirectJumpTargets.cbegin(); it != m_indirectJumpTargets.cend(); ++it)
{
auto& bb = *it;
auto dest = ConstantInt::get(Type::i256, bb->begin());
switchInstr->addCase(dest, bb->llvm());
}
*/
break;
}
case Instruction::JUMPDEST:
{
// Extra asserts just in case.
assert(currentPC == basicBlock.begin());
break;
}
case Instruction::PC:
{
auto value = builder.getIntN(256, currentPC);
stack.push(value);
break;
}
case Instruction::ADDRESS:
{
auto value = ext.address();
stack.push(value);
break;
}
case Instruction::BALANCE:
{
auto address = stack.pop();
auto value = ext.balance(address);
stack.push(value);
break;
}
case Instruction::CALLER:
{
auto value = ext.caller();
stack.push(value);
break;
}
case Instruction::ORIGIN:
{
auto value = ext.origin();
stack.push(value);
break;
}
case Instruction::CALLVALUE:
{
auto value = ext.callvalue();
stack.push(value);
break;
}
case Instruction::CALLDATASIZE:
{
auto value = ext.calldatasize();
stack.push(value);
break;
}
case Instruction::CALLDATALOAD:
{
auto index = stack.pop();
auto value = ext.calldataload(index);
stack.push(value);
break;
}
case Instruction::GASPRICE:
{
auto value = ext.gasprice();
stack.push(value);
break;
}
case Instruction::CODESIZE:
{
auto value = builder.getIntN(256, bytecode.size());
stack.push(value);
break;
}
case Instruction::PREVHASH:
{
auto value = ext.prevhash();
stack.push(value);
break;
}
case Instruction::COINBASE:
{
auto value = ext.coinbase();
stack.push(value);
break;
}
case Instruction::TIMESTAMP:
{
auto value = ext.timestamp();
stack.push(value);
break;
}
case Instruction::NUMBER:
{
auto value = ext.number();
stack.push(value);
break;
}
case Instruction::DIFFICULTY:
{
auto value = ext.difficulty();
stack.push(value);
break;
}
case Instruction::GASLIMIT:
{
auto value = ext.gaslimit();
stack.push(value);
break;
}
case Instruction::CREATE:
{
auto endowment = stack.pop();
auto initOff = stack.pop();
auto initSize = stack.pop();
auto address = ext.create(endowment, initOff, initSize);
stack.push(address);
break;
}
case Instruction::CALL:
{
auto gas = stack.pop();
auto receiveAddress = stack.pop();
auto value = stack.pop();
auto inOff = stack.pop();
auto inSize = stack.pop();
auto outOff = stack.pop();
auto outSize = stack.pop();
auto ret = ext.call(gas, receiveAddress, value, inOff, inSize, outOff, outSize);
stack.push(ret);
break;
}
case Instruction::RETURN:
{
auto index = stack.pop();
auto size = stack.pop();
auto ret = builder.CreateTrunc(index, builder.getInt64Ty());
ret = builder.CreateShl(ret, 32);
size = builder.CreateTrunc(size, i32Ty);
size = builder.CreateZExt(size, builder.getInt64Ty());
ret = builder.CreateOr(ret, size);
builder.CreateRet(ret);
break;
}
case Instruction::SUICIDE:
{
auto address = stack.pop();
ext.suicide(address);
// Fall through
}
case Instruction::STOP:
{
builder.CreateRet(builder.getInt64(0));
break;
}
}
}
if (!builder.GetInsertBlock()->getTerminator()) // If block not terminated
{
if (basicBlock.end() == bytecode.size())
{
// Branch from the last regular block to the final block.
builder.CreateBr(m_finalBlock->llvm());
}
else
{
// Branch to the next block.
auto iterCopy = basicBlockPairIt;
++iterCopy;
auto& next = iterCopy->second;
builder.CreateBr(next);
}
}
}
// Code for special blocks:
// TODO: move to separate function.
// Note: Right now the codegen for special blocks depends only on createBasicBlock(),
// not on the codegen for 'regular' blocks. But it has to be done before linkBasicBlocks().
builder.SetInsertPoint(m_finalBlock->llvm());
builder.CreateRet(builder.getInt64(0));
// TODO: throw an exception or something
builder.SetInsertPoint(m_badJumpBlock->llvm());
builder.CreateRet(builder.getInt64(0));
builder.SetInsertPoint(m_jumpTableBlock->llvm());
if (m_indirectJumpTargets.size() > 0)
{
auto& stack = m_jumpTableBlock->getStack();
auto dest = stack.pop();
auto switchInstr = builder.CreateSwitch(dest, m_badJumpBlock->llvm(),
m_indirectJumpTargets.size());
for (auto it = m_indirectJumpTargets.cbegin(); it != m_indirectJumpTargets.cend(); ++it)
{
auto& bb = *it;
auto dest = ConstantInt::get(Type::i256, bb->begin());
switchInstr->addCase(dest, bb->llvm());
}
}
else
{
builder.CreateRet(builder.getInt64(0));
}
linkBasicBlocks();
return module;
}
void Compiler::linkBasicBlocks()
{
/// Helper function that finds basic block given LLVM basic block pointer
auto findBasicBlock = [this](llvm::BasicBlock* _llbb) -> BasicBlock&
{
// TODO: Fix for finding jumpTableBlock
if (_llbb == this->m_jumpTableBlock->llvm())
return *this->m_jumpTableBlock;
// Name is used to get basic block index (index of first instruction)
// TODO: If basicBlocs are still a map - multikey map can be used
auto&& idxStr = _llbb->getName().substr(sizeof(BasicBlock::NamePrefix) - 2);
auto idx = std::stoul(idxStr);
return basicBlocks.find(idx)->second;
};
auto completePhiNodes = [findBasicBlock](llvm::BasicBlock* _llbb) -> void
{
size_t valueIdx = 0;
auto firstNonPhi = _llbb->getFirstNonPHI();
for (auto instIt = _llbb->begin(); &*instIt != firstNonPhi; ++instIt, ++valueIdx)
{
auto phi = llvm::cast<llvm::PHINode>(instIt);
for (auto predIt = llvm::pred_begin(_llbb); predIt != llvm::pred_end(_llbb); ++predIt)
{
auto& predBB = findBasicBlock(*predIt);
// assert(valueIdx < predBB.getStack().size()); // TODO: Report error
phi->addIncoming(predBB.getStack().get(valueIdx), predBB);
}
}
};
// Link basic blocks
for (auto&& p : basicBlocks)
{
BasicBlock& bb = p.second;
completePhiNodes(bb.llvm());
}
completePhiNodes(m_jumpTableBlock->llvm());
/*
llvm::BasicBlock* llvmBB = bb.llvm();
size_t valueIdx = 0;
auto firstNonPhi = llvmBB->getFirstNonPHI();
for (auto instIt = llvmBB->begin(); &*instIt != firstNonPhi; ++instIt, ++valueIdx)
{
auto phi = llvm::cast<llvm::PHINode>(instIt);
for (auto predIt = llvm::pred_begin(llvmBB); predIt != llvm::pred_end(llvmBB); ++predIt)
{
auto& predBB = findBasicBlock(*predIt);
assert(valueIdx < predBB.getStack().size()); // TODO: Report error
phi->addIncoming(predBB.getStack().get(valueIdx), predBB);
}
}
*/
}
}