Initial skeleton of Subzero.

src/llvm2ice.cpp

+//===- subzero/src/llvm2ice.cpp - Driver for testing ----------------------===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a driver that uses LLVM capabilities to parse a
+// bitcode file and build the LLVM IR, and then convert the LLVM basic
+// blocks, instructions, and operands into their Subzero equivalents.
+//
+//===----------------------------------------------------------------------===//
+
+#include "IceCfg.h"
+#include "IceCfgNode.h"
+#include "IceDefs.h"
+#include "IceInst.h"
+#include "IceOperand.h"
+#include "IceTypes.h"
+
+#include "llvm/IR/Constant.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IRReader/IRReader.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_os_ostream.h"
+#include "llvm/Support/SourceMgr.h"
+
+#include <fstream>
+#include <iostream>
+
+using namespace llvm;
+
+// Debugging helper
+template <typename T> static std::string LLVMObjectAsString(const T *O) {
+  std::string Dump;
+  raw_string_ostream Stream(Dump);
+  O->print(Stream);
+  return Stream.str();
+}
+
+// Converter from LLVM to ICE. The entry point is the convertFunction method.
+//
+// Note: this currently assumes that the given IR was verified to be valid PNaCl
+// bitcode:
+// https://developers.google.com/native-client/dev/reference/pnacl-bitcode-abi
+// If not, all kinds of assertions may fire.
+//
+class LLVM2ICEConverter {
+public:
+  LLVM2ICEConverter() : Cfg(NULL), CurrentNode(NULL) {}
+
+  IceCfg *convertFunction(const Function *F) {
+    VarMap.clear();
+    NodeMap.clear();
+    Cfg = new IceCfg;
+    Cfg->setName(F->getName());
+    Cfg->setReturnType(convertType(F->getReturnType()));
+    Cfg->setInternal(F->hasInternalLinkage());
+
+    // The initial definition/use of each arg is the entry node.
+    CurrentNode = mapBasicBlockToNode(&F->getEntryBlock());
+    for (Function::const_arg_iterator ArgI = F->arg_begin(),
+                                      ArgE = F->arg_end();
+         ArgI != ArgE; ++ArgI) {
+      Cfg->addArg(mapValueToIceVar(ArgI));
+    }
+
+    // Make an initial pass through the block list just to resolve the
+    // blocks in the original linearized order.  Otherwise the ICE
+    // linearized order will be affected by branch targets in
+    // terminator instructions.
+    for (Function::const_iterator BBI = F->begin(), BBE = F->end(); BBI != BBE;
+         ++BBI) {
+      mapBasicBlockToNode(BBI);
+    }
+    for (Function::const_iterator BBI = F->begin(), BBE = F->end(); BBI != BBE;
+         ++BBI) {
+      CurrentNode = mapBasicBlockToNode(BBI);
+      convertBasicBlock(BBI);
+    }
+    Cfg->setEntryNode(mapBasicBlockToNode(&F->getEntryBlock()));
+    Cfg->registerEdges();
+
+    return Cfg;
+  }
+
+private:
+  // LLVM values (instructions, etc.) are mapped directly to ICE variables.
+  // mapValueToIceVar has a version that forces an ICE type on the variable,
+  // and a version that just uses convertType on V.
+  IceVariable *mapValueToIceVar(const Value *V, IceType IceTy) {
+    if (IceTy == IceType_void)
+      return NULL;
+    if (VarMap.find(V) == VarMap.end()) {
+      assert(CurrentNode);
+      VarMap[V] = Cfg->makeVariable(IceTy, CurrentNode, V->getName());
+    }
+    return VarMap[V];
+  }
+
+  IceVariable *mapValueToIceVar(const Value *V) {
+    return mapValueToIceVar(V, convertType(V->getType()));
+  }
+
+  IceCfgNode *mapBasicBlockToNode(const BasicBlock *BB) {
+    if (NodeMap.find(BB) == NodeMap.end()) {
+      NodeMap[BB] = Cfg->makeNode(BB->getName());
+    }
+    return NodeMap[BB];
+  }
+
+  IceType convertIntegerType(const IntegerType *IntTy) {
+    switch (IntTy->getBitWidth()) {
+    case 1:
+      return IceType_i1;
+    case 8:
+      return IceType_i8;
+    case 16:
+      return IceType_i16;
+    case 32:
+      return IceType_i32;
+    case 64:
+      return IceType_i64;
+    default:
+      report_fatal_error(std::string("Invalid PNaCl int type: ") +
+                         LLVMObjectAsString(IntTy));
+      return IceType_void;
+    }
+  }
+
+  IceType convertType(const Type *Ty) {
+    switch (Ty->getTypeID()) {
+    case Type::VoidTyID:
+      return IceType_void;
+    case Type::IntegerTyID:
+      return convertIntegerType(cast<IntegerType>(Ty));
+    case Type::FloatTyID:
+      return IceType_f32;
+    case Type::DoubleTyID:
+      return IceType_f64;
+    case Type::PointerTyID: {
+      const PointerType *PTy = cast<PointerType>(Ty);
+      return convertType(PTy->getElementType());
+    }
+    case Type::FunctionTyID:
+      return IceType_i32;
+    default:
+      report_fatal_error(std::string("Invalid PNaCl type: ") +
+                         LLVMObjectAsString(Ty));
+    }
+
+    llvm_unreachable("convertType");
+    return IceType_void;
+  }
+
+  // Given a LLVM instruction and an operand number, produce the IceOperand this
+  // refers to. If there's no such operand, return NULL.
+  IceOperand *convertOperand(const Instruction *Inst, unsigned OpNum) {
+    if (OpNum >= Inst->getNumOperands()) {
+      return NULL;
+    }
+    const Value *Op = Inst->getOperand(OpNum);
+    return convertValue(Op);
+  }
+
+  IceOperand *convertValue(const Value *Op) {
+    if (const Constant *Const = dyn_cast<Constant>(Op)) {
+      if (const GlobalValue *GV = dyn_cast<GlobalValue>(Const)) {
+        return Cfg->getConstantSym(convertType(GV->getType()), GV, 0,
+                                   GV->getName());
+      } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(Const)) {
+        return Cfg->getConstantInt(convertIntegerType(CI->getType()),
+                                   CI->getZExtValue());
+      } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(Const)) {
+        IceType Type = convertType(CFP->getType());
+        if (Type == IceType_f32)
+          return Cfg->getConstantFloat(CFP->getValueAPF().convertToFloat());
+        else if (Type == IceType_f64)
+          return Cfg->getConstantDouble(CFP->getValueAPF().convertToDouble());
+        assert(0 && "Unexpected floating point type");
+        return NULL;
+      } else {
+        assert(0 && "Unhandled constant type");
+        return NULL;
+      }
+    } else {
+      return mapValueToIceVar(Op);
+    }
+  }
+
+  // Note: this currently assumes a 1x1 mapping between LLVM IR and Ice
+  // instructions.
+  IceInst *convertInstruction(const Instruction *Inst) {
+    switch (Inst->getOpcode()) {
+    case Instruction::PHI:
+      return convertPHINodeInstruction(cast<PHINode>(Inst));
+    case Instruction::Br:
+      return convertBrInstruction(cast<BranchInst>(Inst));
+    case Instruction::Ret:
+      return convertRetInstruction(cast<ReturnInst>(Inst));
+    case Instruction::IntToPtr:
+      return convertIntToPtrInstruction(cast<IntToPtrInst>(Inst));
+    case Instruction::PtrToInt:
+      return convertPtrToIntInstruction(cast<PtrToIntInst>(Inst));
+    case Instruction::ICmp:
+      return convertICmpInstruction(cast<ICmpInst>(Inst));
+    case Instruction::FCmp:
+      return convertFCmpInstruction(cast<FCmpInst>(Inst));
+    case Instruction::Select:
+      return convertSelectInstruction(cast<SelectInst>(Inst));
+    case Instruction::Switch:
+      return convertSwitchInstruction(cast<SwitchInst>(Inst));
+    case Instruction::Load:
+      return convertLoadInstruction(cast<LoadInst>(Inst));
+    case Instruction::Store:
+      return convertStoreInstruction(cast<StoreInst>(Inst));
+    case Instruction::ZExt:
+      return convertCastInstruction(cast<ZExtInst>(Inst), IceInstCast::Zext);
+    case Instruction::SExt:
+      return convertCastInstruction(cast<SExtInst>(Inst), IceInstCast::Sext);
+    case Instruction::Trunc:
+      return convertCastInstruction(cast<TruncInst>(Inst), IceInstCast::Trunc);
+    case Instruction::FPTrunc:
+      return convertCastInstruction(cast<FPTruncInst>(Inst),
+                                    IceInstCast::Fptrunc);
+    case Instruction::FPExt:
+      return convertCastInstruction(cast<FPExtInst>(Inst), IceInstCast::Fpext);
+    case Instruction::FPToSI:
+      return convertCastInstruction(cast<FPToSIInst>(Inst),
+                                    IceInstCast::Fptosi);
+    case Instruction::FPToUI:
+      return convertCastInstruction(cast<FPToUIInst>(Inst),
+                                    IceInstCast::Fptoui);
+    case Instruction::SIToFP:
+      return convertCastInstruction(cast<SIToFPInst>(Inst),
+                                    IceInstCast::Sitofp);
+    case Instruction::UIToFP:
+      return convertCastInstruction(cast<UIToFPInst>(Inst),
+                                    IceInstCast::Uitofp);
+    case Instruction::Add:
+      return convertArithInstruction(Inst, IceInstArithmetic::Add);
+    case Instruction::Sub:
+      return convertArithInstruction(Inst, IceInstArithmetic::Sub);
+    case Instruction::Mul:
+      return convertArithInstruction(Inst, IceInstArithmetic::Mul);
+    case Instruction::UDiv:
+      return convertArithInstruction(Inst, IceInstArithmetic::Udiv);
+    case Instruction::SDiv:
+      return convertArithInstruction(Inst, IceInstArithmetic::Sdiv);
+    case Instruction::URem:
+      return convertArithInstruction(Inst, IceInstArithmetic::Urem);
+    case Instruction::SRem:
+      return convertArithInstruction(Inst, IceInstArithmetic::Srem);
+    case Instruction::Shl:
+      return convertArithInstruction(Inst, IceInstArithmetic::Shl);
+    case Instruction::LShr:
+      return convertArithInstruction(Inst, IceInstArithmetic::Lshr);
+    case Instruction::AShr:
+      return convertArithInstruction(Inst, IceInstArithmetic::Ashr);
+    case Instruction::FAdd:
+      return convertArithInstruction(Inst, IceInstArithmetic::Fadd);
+    case Instruction::FSub:
+      return convertArithInstruction(Inst, IceInstArithmetic::Fsub);
+    case Instruction::FMul:
+      return convertArithInstruction(Inst, IceInstArithmetic::Fmul);
+    case Instruction::FDiv:
+      return convertArithInstruction(Inst, IceInstArithmetic::Fdiv);
+    case Instruction::FRem:
+      return convertArithInstruction(Inst, IceInstArithmetic::Frem);
+    case Instruction::And:
+      return convertArithInstruction(Inst, IceInstArithmetic::And);
+    case Instruction::Or:
+      return convertArithInstruction(Inst, IceInstArithmetic::Or);
+    case Instruction::Xor:
+      return convertArithInstruction(Inst, IceInstArithmetic::Xor);
+    case Instruction::Call:
+      return convertCallInstruction(cast<CallInst>(Inst));
+    case Instruction::Alloca:
+      return convertAllocaInstruction(cast<AllocaInst>(Inst));
+    default:
+      report_fatal_error(std::string("Invalid PNaCl instruction: ") +
+                         LLVMObjectAsString(Inst));
+    }
+
+    llvm_unreachable("convertInstruction");
+    return NULL;
+  }
+
+  IceInst *convertLoadInstruction(const LoadInst *Inst) {
+    IceOperand *Src = convertOperand(Inst, 0);
+    IceVariable *Dest = mapValueToIceVar(Inst);
+    return IceInstLoad::create(Cfg, Dest, Src);
+  }
+
+  IceInst *convertStoreInstruction(const StoreInst *Inst) {
+    IceOperand *Addr = convertOperand(Inst, 1);
+    IceOperand *Val = convertOperand(Inst, 0);
+    return IceInstStore::create(Cfg, Val, Addr);
+  }
+
+  IceInst *convertArithInstruction(const Instruction *Inst,
+                                   IceInstArithmetic::OpKind Opcode) {
+    const BinaryOperator *BinOp = cast<BinaryOperator>(Inst);
+    IceOperand *Src0 = convertOperand(Inst, 0);
+    IceOperand *Src1 = convertOperand(Inst, 1);
+    IceVariable *Dest = mapValueToIceVar(BinOp);
+    return IceInstArithmetic::create(Cfg, Opcode, Dest, Src0, Src1);
+  }
+
+  IceInst *convertPHINodeInstruction(const PHINode *Inst) {
+    unsigned NumValues = Inst->getNumIncomingValues();
+    IceInstPhi *IcePhi =
+        IceInstPhi::create(Cfg, NumValues, mapValueToIceVar(Inst));
+    for (unsigned N = 0, E = NumValues; N != E; ++N) {
+      IcePhi->addArgument(convertOperand(Inst, N),
+                          mapBasicBlockToNode(Inst->getIncomingBlock(N)));
+    }
+    return IcePhi;
+  }
+
+  IceInst *convertBrInstruction(const BranchInst *Inst) {
+    if (Inst->isConditional()) {
+      IceOperand *Src = convertOperand(Inst, 0);
+      BasicBlock *BBThen = Inst->getSuccessor(0);
+      BasicBlock *BBElse = Inst->getSuccessor(1);
+      IceCfgNode *NodeThen = mapBasicBlockToNode(BBThen);
+      IceCfgNode *NodeElse = mapBasicBlockToNode(BBElse);
+      return IceInstBr::create(Cfg, Src, NodeThen, NodeElse);
+    } else {
+      BasicBlock *BBSucc = Inst->getSuccessor(0);
+      return IceInstBr::create(Cfg, mapBasicBlockToNode(BBSucc));
+    }
+  }
+
+  IceInst *convertIntToPtrInstruction(const IntToPtrInst *Inst) {
+    IceOperand *Src = convertOperand(Inst, 0);
+    IceVariable *Dest = mapValueToIceVar(Inst, IceType_i32);
+    return IceInstAssign::create(Cfg, Dest, Src);
+  }
+
+  IceInst *convertPtrToIntInstruction(const PtrToIntInst *Inst) {
+    IceOperand *Src = convertOperand(Inst, 0);
+    IceVariable *Dest = mapValueToIceVar(Inst);
+    return IceInstAssign::create(Cfg, Dest, Src);
+  }
+
+  IceInst *convertRetInstruction(const ReturnInst *Inst) {
+    IceOperand *RetOperand = convertOperand(Inst, 0);
+    if (RetOperand) {
+      return IceInstRet::create(Cfg, RetOperand);
+    } else {
+      return IceInstRet::create(Cfg);
+    }
+  }
+
+  IceInst *convertCastInstruction(const Instruction *Inst,
+                                  IceInstCast::OpKind CastKind) {
+    IceOperand *Src = convertOperand(Inst, 0);
+    IceVariable *Dest = mapValueToIceVar(Inst);
+    return IceInstCast::create(Cfg, CastKind, Dest, Src);
+  }
+
+  IceInst *convertICmpInstruction(const ICmpInst *Inst) {
+    IceOperand *Src0 = convertOperand(Inst, 0);
+    IceOperand *Src1 = convertOperand(Inst, 1);
+    IceVariable *Dest = mapValueToIceVar(Inst);
+
+    IceInstIcmp::ICond Cond;
+    switch (Inst->getPredicate()) {
+    default:
+      llvm_unreachable("ICmpInst predicate");
+    case CmpInst::ICMP_EQ:
+      Cond = IceInstIcmp::Eq;
+      break;
+    case CmpInst::ICMP_NE:
+      Cond = IceInstIcmp::Ne;
+      break;
+    case CmpInst::ICMP_UGT:
+      Cond = IceInstIcmp::Ugt;
+      break;
+    case CmpInst::ICMP_UGE:
+      Cond = IceInstIcmp::Uge;
+      break;
+    case CmpInst::ICMP_ULT:
+      Cond = IceInstIcmp::Ult;
+      break;
+    case CmpInst::ICMP_ULE:
+      Cond = IceInstIcmp::Ule;
+      break;
+    case CmpInst::ICMP_SGT:
+      Cond = IceInstIcmp::Sgt;
+      break;
+    case CmpInst::ICMP_SGE:
+      Cond = IceInstIcmp::Sge;
+      break;
+    case CmpInst::ICMP_SLT:
+      Cond = IceInstIcmp::Slt;
+      break;
+    case CmpInst::ICMP_SLE:
+      Cond = IceInstIcmp::Sle;
+      break;
+    }
+
+    return IceInstIcmp::create(Cfg, Cond, Dest, Src0, Src1);
+  }
+
+  IceInst *convertFCmpInstruction(const FCmpInst *Inst) {
+    IceOperand *Src0 = convertOperand(Inst, 0);
+    IceOperand *Src1 = convertOperand(Inst, 1);
+    IceVariable *Dest = mapValueToIceVar(Inst);
+
+    IceInstFcmp::FCond Cond;
+    switch (Inst->getPredicate()) {
+
+    default:
+      llvm_unreachable("FCmpInst predicate");
+
+    case CmpInst::FCMP_FALSE:
+      Cond = IceInstFcmp::False;
+      break;
+    case CmpInst::FCMP_OEQ:
+      Cond = IceInstFcmp::Oeq;
+      break;
+    case CmpInst::FCMP_OGT:
+      Cond = IceInstFcmp::Ogt;
+      break;
+    case CmpInst::FCMP_OGE:
+      Cond = IceInstFcmp::Oge;
+      break;
+    case CmpInst::FCMP_OLT:
+      Cond = IceInstFcmp::Olt;
+      break;
+    case CmpInst::FCMP_OLE:
+      Cond = IceInstFcmp::Ole;
+      break;
+    case CmpInst::FCMP_ONE:
+      Cond = IceInstFcmp::One;
+      break;
+    case CmpInst::FCMP_ORD:
+      Cond = IceInstFcmp::Ord;
+      break;
+    case CmpInst::FCMP_UEQ:
+      Cond = IceInstFcmp::Ueq;
+      break;
+    case CmpInst::FCMP_UGT:
+      Cond = IceInstFcmp::Ugt;
+      break;
+    case CmpInst::FCMP_UGE:
+      Cond = IceInstFcmp::Uge;
+      break;
+    case CmpInst::FCMP_ULT:
+      Cond = IceInstFcmp::Ult;
+      break;
+    case CmpInst::FCMP_ULE:
+      Cond = IceInstFcmp::Ule;
+      break;
+    case CmpInst::FCMP_UNE:
+      Cond = IceInstFcmp::Une;
+      break;
+    case CmpInst::FCMP_UNO:
+      Cond = IceInstFcmp::Uno;
+      break;
+    case CmpInst::FCMP_TRUE:
+      Cond = IceInstFcmp::True;
+      break;
+    }
+
+    return IceInstFcmp::create(Cfg, Cond, Dest, Src0, Src1);
+  }
+
+  IceInst *convertSelectInstruction(const SelectInst *Inst) {
+    IceVariable *Dest = mapValueToIceVar(Inst);
+    IceOperand *Cond = convertValue(Inst->getCondition());
+    IceOperand *Source1 = convertValue(Inst->getTrueValue());
+    IceOperand *Source2 = convertValue(Inst->getFalseValue());
+    return IceInstSelect::create(Cfg, Dest, Cond, Source1, Source2);
+  }
+
+  IceInst *convertSwitchInstruction(const SwitchInst *Inst) {
+    IceOperand *Source = convertValue(Inst->getCondition());
+    IceCfgNode *LabelDefault = mapBasicBlockToNode(Inst->getDefaultDest());
+    unsigned NumCases = Inst->getNumCases();
+    IceInstSwitch *Switch =
+        IceInstSwitch::create(Cfg, NumCases, Source, LabelDefault);
+    unsigned CurrentCase = 0;
+    for (SwitchInst::ConstCaseIt I = Inst->case_begin(), E = Inst->case_end();
+         I != E; ++I, ++CurrentCase) {
+      uint64_t CaseValue = I.getCaseValue()->getZExtValue();
+      IceCfgNode *CaseSuccessor = mapBasicBlockToNode(I.getCaseSuccessor());
+      Switch->addBranch(CurrentCase, CaseValue, CaseSuccessor);
+    }
+    return Switch;
+  }
+
+  IceInst *convertCallInstruction(const CallInst *Inst) {
+    IceVariable *Dest = mapValueToIceVar(Inst);
+    IceOperand *CallTarget = convertValue(Inst->getCalledValue());
+    unsigned NumArgs = Inst->getNumArgOperands();
+    IceInstCall *NewInst =
+        IceInstCall::create(Cfg, NumArgs, Dest, CallTarget, Inst->isTailCall());
+    for (unsigned i = 0; i < NumArgs; ++i) {
+      NewInst->addArg(convertOperand(Inst, i));
+    }
+    return NewInst;
+  }
+
+  IceInst *convertAllocaInstruction(const AllocaInst *Inst) {
+    // PNaCl bitcode only contains allocas of byte-granular objects.
+    IceOperand *ByteCount = convertValue(Inst->getArraySize());
+    uint32_t Align = Inst->getAlignment();
+    IceVariable *Dest = mapValueToIceVar(Inst, IceType_i32);
+
+    return IceInstAlloca::create(Cfg, ByteCount, Align, Dest);
+  }
+
+  IceCfgNode *convertBasicBlock(const BasicBlock *BB) {
+    IceCfgNode *Node = mapBasicBlockToNode(BB);
+    for (BasicBlock::const_iterator II = BB->begin(), II_e = BB->end();
+         II != II_e; ++II) {
+      IceInst *Inst = convertInstruction(II);
+      Node->appendInst(Inst);
+    }
+    return Node;
+  }
+
+private:
+  // Data
+  IceCfg *Cfg;
+  IceCfgNode *CurrentNode;
+  std::map<const Value *, IceVariable *> VarMap;
+  std::map<const BasicBlock *, IceCfgNode *> NodeMap;
+};
+
+static cl::list<IceVerbose> VerboseList(
+    "verbose", cl::CommaSeparated,
+    cl::desc("Verbose options (can be comma-separated):"),
+    cl::values(
+        clEnumValN(IceV_Instructions, "inst", "Print basic instructions"),
+        clEnumValN(IceV_Deleted, "del", "Include deleted instructions"),
+        clEnumValN(IceV_InstNumbers, "instnum", "Print instruction numbers"),
+        clEnumValN(IceV_Preds, "pred", "Show predecessors"),
+        clEnumValN(IceV_Succs, "succ", "Show successors"),
+        clEnumValN(IceV_Liveness, "live", "Liveness information"),
+        clEnumValN(IceV_RegManager, "rmgr", "Register manager status"),
+        clEnumValN(IceV_RegOrigins, "orig", "Physical register origins"),
+        clEnumValN(IceV_LinearScan, "regalloc", "Linear scan details"),
+        clEnumValN(IceV_Frame, "frame", "Stack frame layout details"),
+        clEnumValN(IceV_Timing, "time", "Pass timing details"),
+        clEnumValN(IceV_All, "all", "Use all verbose options"),
+        clEnumValN(IceV_None, "none", "No verbosity"), clEnumValEnd));
+static cl::opt<std::string> IRFilename(cl::Positional, cl::desc("<IR file>"),
+                                       cl::Required);
+static cl::opt<std::string> OutputFilename("o",
+                                           cl::desc("Override output filename"),
+                                           cl::init("-"),
+                                           cl::value_desc("filename"));
+static cl::opt<std::string>
+TestPrefix("prefix", cl::desc("Prepend a prefix to symbol names for testing"),
+           cl::init(""), cl::value_desc("prefix"));
+static cl::opt<bool>
+DisableInternal("external",
+                cl::desc("Disable 'internal' linkage type for testing"));
+static cl::opt<bool>
+DisableTranslation("notranslate", cl::desc("Disable Subzero translation"));
+
+static cl::opt<bool> SubzeroTimingEnabled(
+    "timing", cl::desc("Enable breakdown timing of Subzero translation"));
+
+int main(int argc, char **argv) {
+  cl::ParseCommandLineOptions(argc, argv);
+
+  // Parse the input LLVM IR file into a module.
+  SMDiagnostic Err;
+  Module *Mod;
+
+  {
+    IceTimer T;
+    Mod = ParseIRFile(IRFilename, Err, getGlobalContext());
+
+    if (SubzeroTimingEnabled) {
+      std::cerr << "[Subzero timing] IR Parsing: " << T.getElapsedSec()
+                << " sec\n";
+    }
+  }
+
+  if (!Mod) {
+    Err.print(argv[0], errs());
+    return 1;
+  }
+
+  IceVerboseMask VerboseMask = IceV_None;
+  for (unsigned i = 0; i != VerboseList.size(); ++i)
+    VerboseMask |= VerboseList[i];
+
+  std::ofstream Ofs;
+  if (OutputFilename != "-") {
+    Ofs.open(OutputFilename.c_str(), std::ofstream::out);
+  }
+  raw_os_ostream *Os =
+      new raw_os_ostream(OutputFilename == "-" ? std::cout : Ofs);
+  Os->SetUnbuffered();
+
+  for (Module::const_iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
+    if (I->empty())
+      continue;
+    LLVM2ICEConverter FunctionConverter;
+
+    IceTimer TConvert;
+    IceCfg *Cfg = FunctionConverter.convertFunction(I);
+    if (DisableInternal)
+      Cfg->setInternal(false);
+
+    if (SubzeroTimingEnabled) {
+      std::cerr << "[Subzero timing] Convert function " << Cfg->getName()
+                << ": " << TConvert.getElapsedSec() << " sec\n";
+    }
+
+    Cfg->setTestPrefix(TestPrefix);
+    Cfg->Str.Stream = Os;
+    Cfg->Str.setVerbose(VerboseMask);
+    if (DisableTranslation) {
+      Cfg->dump();
+    }
+  }
+
+  return 0;
+}