diff --git a/lib/Frontend/Backend.cpp b/lib/Frontend/Backend.cpp
new file mode 100644
index 0000000..f5291a9
--- /dev/null
+++ b/lib/Frontend/Backend.cpp
@@ -0,0 +1,433 @@
+//===--- Backend.cpp - Interface to LLVM backend technologies -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/ASTConsumers.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclGroup.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Basic/TargetOptions.h"
+#include "clang/CodeGen/CodeGenOptions.h"
+#include "clang/CodeGen/ModuleBuilder.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Assembly/PrintModulePass.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/CodeGen/RegAllocRegistry.h"
+#include "llvm/CodeGen/SchedulerRegistry.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/StandardPasses.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Target/SubtargetFeature.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Target/TargetRegistry.h"
+using namespace clang;
+using namespace llvm;
+
+namespace {
+  class BackendConsumer : public ASTConsumer {
+    Diagnostic &Diags;
+    BackendAction Action;
+    const CodeGenOptions &CodeGenOpts;
+    const LangOptions &LangOpts;
+    const TargetOptions &TargetOpts;
+    llvm::raw_ostream *AsmOutStream;
+    llvm::formatted_raw_ostream FormattedOutStream;
+    ASTContext *Context;
+
+    Timer LLVMIRGeneration;
+    Timer CodeGenerationTime;
+
+    llvm::OwningPtr<CodeGenerator> Gen;
+
+    llvm::Module *TheModule;
+    llvm::TargetData *TheTargetData;
+
+    mutable FunctionPassManager *CodeGenPasses;
+    mutable PassManager *PerModulePasses;
+    mutable FunctionPassManager *PerFunctionPasses;
+
+    FunctionPassManager *getCodeGenPasses() const;
+    PassManager *getPerModulePasses() const;
+    FunctionPassManager *getPerFunctionPasses() const;
+
+    void CreatePasses();
+
+    /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
+    ///
+    /// \return True on success.
+    bool AddEmitPasses();
+
+    void EmitAssembly();
+
+  public:
+    BackendConsumer(BackendAction action, Diagnostic &_Diags,
+                    const LangOptions &langopts, const CodeGenOptions &compopts,
+                    const TargetOptions &targetopts, bool TimePasses,
+                    const std::string &infile, llvm::raw_ostream *OS,
+                    LLVMContext& C) :
+      Diags(_Diags),
+      Action(action),
+      CodeGenOpts(compopts),
+      LangOpts(langopts),
+      TargetOpts(targetopts),
+      AsmOutStream(OS),
+      LLVMIRGeneration("LLVM IR Generation Time"),
+      CodeGenerationTime("Code Generation Time"),
+      Gen(CreateLLVMCodeGen(Diags, infile, compopts, C)),
+      TheModule(0), TheTargetData(0),
+      CodeGenPasses(0), PerModulePasses(0), PerFunctionPasses(0) {
+
+      if (AsmOutStream)
+        FormattedOutStream.setStream(*AsmOutStream,
+                                     formatted_raw_ostream::PRESERVE_STREAM);
+
+      llvm::TimePassesIsEnabled = TimePasses;
+    }
+
+    ~BackendConsumer() {
+      delete TheTargetData;
+      delete TheModule;
+      delete CodeGenPasses;
+      delete PerModulePasses;
+      delete PerFunctionPasses;
+    }
+
+    virtual void Initialize(ASTContext &Ctx) {
+      Context = &Ctx;
+
+      if (llvm::TimePassesIsEnabled)
+        LLVMIRGeneration.startTimer();
+
+      Gen->Initialize(Ctx);
+
+      TheModule = Gen->GetModule();
+      TheTargetData = new llvm::TargetData(Ctx.Target.getTargetDescription());
+
+      if (llvm::TimePassesIsEnabled)
+        LLVMIRGeneration.stopTimer();
+    }
+
+    virtual void HandleTopLevelDecl(DeclGroupRef D) {
+      PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
+                                     Context->getSourceManager(),
+                                     "LLVM IR generation of declaration");
+
+      if (llvm::TimePassesIsEnabled)
+        LLVMIRGeneration.startTimer();
+
+      Gen->HandleTopLevelDecl(D);
+
+      if (llvm::TimePassesIsEnabled)
+        LLVMIRGeneration.stopTimer();
+    }
+
+    virtual void HandleTranslationUnit(ASTContext &C) {
+      {
+        PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
+        if (llvm::TimePassesIsEnabled)
+          LLVMIRGeneration.startTimer();
+
+        Gen->HandleTranslationUnit(C);
+
+        if (llvm::TimePassesIsEnabled)
+          LLVMIRGeneration.stopTimer();
+      }
+
+      // EmitAssembly times and registers crash info itself.
+      EmitAssembly();
+
+      // Force a flush here in case we never get released.
+      if (AsmOutStream)
+        FormattedOutStream.flush();
+    }
+
+    virtual void HandleTagDeclDefinition(TagDecl *D) {
+      PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
+                                     Context->getSourceManager(),
+                                     "LLVM IR generation of declaration");
+      Gen->HandleTagDeclDefinition(D);
+    }
+
+    virtual void CompleteTentativeDefinition(VarDecl *D) {
+      Gen->CompleteTentativeDefinition(D);
+    }
+  };
+}
+
+FunctionPassManager *BackendConsumer::getCodeGenPasses() const {
+  if (!CodeGenPasses) {
+    CodeGenPasses = new FunctionPassManager(TheModule);
+    CodeGenPasses->add(new TargetData(*TheTargetData));
+  }
+
+  return CodeGenPasses;
+}
+
+PassManager *BackendConsumer::getPerModulePasses() const {
+  if (!PerModulePasses) {
+    PerModulePasses = new PassManager();
+    PerModulePasses->add(new TargetData(*TheTargetData));
+  }
+
+  return PerModulePasses;
+}
+
+FunctionPassManager *BackendConsumer::getPerFunctionPasses() const {
+  if (!PerFunctionPasses) {
+    PerFunctionPasses = new FunctionPassManager(TheModule);
+    PerFunctionPasses->add(new TargetData(*TheTargetData));
+  }
+
+  return PerFunctionPasses;
+}
+
+bool BackendConsumer::AddEmitPasses() {
+  if (Action == Backend_EmitNothing)
+    return true;
+
+  if (Action == Backend_EmitBC) {
+    getPerModulePasses()->add(createBitcodeWriterPass(FormattedOutStream));
+  } else if (Action == Backend_EmitLL) {
+    getPerModulePasses()->add(createPrintModulePass(&FormattedOutStream));
+  } else {
+    bool Fast = CodeGenOpts.OptimizationLevel == 0;
+
+    // Create the TargetMachine for generating code.
+    std::string Error;
+    std::string Triple = TheModule->getTargetTriple();
+    const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
+    if (!TheTarget) {
+      Diags.Report(diag::err_fe_unable_to_create_target) << Error;
+      return false;
+    }
+
+    // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
+    // being gross, this is also totally broken if we ever care about
+    // concurrency.
+    llvm::NoFramePointerElim = CodeGenOpts.DisableFPElim;
+    if (CodeGenOpts.FloatABI == "soft")
+      llvm::FloatABIType = llvm::FloatABI::Soft;
+    else if (CodeGenOpts.FloatABI == "hard")
+      llvm::FloatABIType = llvm::FloatABI::Hard;
+    else {
+      assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
+      llvm::FloatABIType = llvm::FloatABI::Default;
+    }
+    NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
+    llvm::UseSoftFloat = CodeGenOpts.SoftFloat;
+    UnwindTablesMandatory = CodeGenOpts.UnwindTables;
+
+    TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
+
+    // FIXME: Parse this earlier.
+    if (CodeGenOpts.RelocationModel == "static") {
+      TargetMachine::setRelocationModel(llvm::Reloc::Static);
+    } else if (CodeGenOpts.RelocationModel == "pic") {
+      TargetMachine::setRelocationModel(llvm::Reloc::PIC_);
+    } else {
+      assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
+             "Invalid PIC model!");
+      TargetMachine::setRelocationModel(llvm::Reloc::DynamicNoPIC);
+    }
+    // FIXME: Parse this earlier.
+    if (CodeGenOpts.CodeModel == "small") {
+      TargetMachine::setCodeModel(llvm::CodeModel::Small);
+    } else if (CodeGenOpts.CodeModel == "kernel") {
+      TargetMachine::setCodeModel(llvm::CodeModel::Kernel);
+    } else if (CodeGenOpts.CodeModel == "medium") {
+      TargetMachine::setCodeModel(llvm::CodeModel::Medium);
+    } else if (CodeGenOpts.CodeModel == "large") {
+      TargetMachine::setCodeModel(llvm::CodeModel::Large);
+    } else {
+      assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
+      TargetMachine::setCodeModel(llvm::CodeModel::Default);
+    }
+
+    std::vector<const char *> BackendArgs;
+    BackendArgs.push_back("clang"); // Fake program name.
+    if (!CodeGenOpts.DebugPass.empty()) {
+      BackendArgs.push_back("-debug-pass");
+      BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
+    }
+    if (!CodeGenOpts.LimitFloatPrecision.empty()) {
+      BackendArgs.push_back("-limit-float-precision");
+      BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
+    }
+    if (llvm::TimePassesIsEnabled)
+      BackendArgs.push_back("-time-passes");
+    BackendArgs.push_back(0);
+    llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
+                                      (char**) &BackendArgs[0]);
+
+    std::string FeaturesStr;
+    if (TargetOpts.CPU.size() || TargetOpts.Features.size()) {
+      SubtargetFeatures Features;
+      Features.setCPU(TargetOpts.CPU);
+      for (std::vector<std::string>::const_iterator
+             it = TargetOpts.Features.begin(),
+             ie = TargetOpts.Features.end(); it != ie; ++it)
+        Features.AddFeature(*it);
+      FeaturesStr = Features.getString();
+    }
+    TargetMachine *TM = TheTarget->createTargetMachine(Triple, FeaturesStr);
+
+    // Set register scheduler & allocation policy.
+    RegisterScheduler::setDefault(createDefaultScheduler);
+    RegisterRegAlloc::setDefault(Fast ? createLocalRegisterAllocator :
+                                 createLinearScanRegisterAllocator);
+
+    // From llvm-gcc:
+    // If there are passes we have to run on the entire module, we do codegen
+    // as a separate "pass" after that happens.
+    // FIXME: This is disabled right now until bugs can be worked out.  Reenable
+    // this for fast -O0 compiles!
+    FunctionPassManager *PM = getCodeGenPasses();
+    CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
+
+    switch (CodeGenOpts.OptimizationLevel) {
+    default: break;
+    case 0: OptLevel = CodeGenOpt::None; break;
+    case 3: OptLevel = CodeGenOpt::Aggressive; break;
+    }
+
+    // Normal mode, emit a .s or .o file by running the code generator. Note,
+    // this also adds codegenerator level optimization passes.
+    TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
+    if (Action == Backend_EmitObj)
+      CGFT = TargetMachine::CGFT_ObjectFile;
+    if (TM->addPassesToEmitFile(*PM, FormattedOutStream, CGFT, OptLevel)) {
+      Diags.Report(diag::err_fe_unable_to_interface_with_target);
+      return false;
+    }
+  }
+
+  return true;
+}
+
+void BackendConsumer::CreatePasses() {
+  unsigned OptLevel = CodeGenOpts.OptimizationLevel;
+  CodeGenOptions::InliningMethod Inlining = CodeGenOpts.Inlining;
+
+  // Handle disabling of LLVM optimization, where we want to preserve the
+  // internal module before any optimization.
+  if (CodeGenOpts.DisableLLVMOpts) {
+    OptLevel = 0;
+    Inlining = CodeGenOpts.NoInlining;
+  }
+
+  // In -O0 if checking is disabled, we don't even have per-function passes.
+  if (CodeGenOpts.VerifyModule)
+    getPerFunctionPasses()->add(createVerifierPass());
+
+  // Assume that standard function passes aren't run for -O0.
+  if (OptLevel > 0)
+    llvm::createStandardFunctionPasses(getPerFunctionPasses(), OptLevel);
+
+  llvm::Pass *InliningPass = 0;
+  switch (Inlining) {
+  case CodeGenOptions::NoInlining: break;
+  case CodeGenOptions::NormalInlining: {
+    // Set the inline threshold following llvm-gcc.
+    //
+    // FIXME: Derive these constants in a principled fashion.
+    unsigned Threshold = 225;
+    if (CodeGenOpts.OptimizeSize)
+      Threshold = 75;
+    else if (OptLevel > 2)
+      Threshold = 275;
+    InliningPass = createFunctionInliningPass(Threshold);
+    break;
+  }
+  case CodeGenOptions::OnlyAlwaysInlining:
+    InliningPass = createAlwaysInlinerPass();         // Respect always_inline
+    break;
+  }
+
+  // For now we always create per module passes.
+  PassManager *PM = getPerModulePasses();
+  llvm::createStandardModulePasses(PM, OptLevel, CodeGenOpts.OptimizeSize,
+                                   CodeGenOpts.UnitAtATime,
+                                   CodeGenOpts.UnrollLoops,
+                                   /*SimplifyLibCalls=*/!LangOpts.NoBuiltin,
+                                   /*HaveExceptions=*/true,
+                                   InliningPass);
+}
+
+/// EmitAssembly - Handle interaction with LLVM backend to generate
+/// actual machine code.
+void BackendConsumer::EmitAssembly() {
+  // Silently ignore if we weren't initialized for some reason.
+  if (!TheModule || !TheTargetData)
+    return;
+
+  TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
+
+  // Make sure IR generation is happy with the module. This is
+  // released by the module provider.
+  Module *M = Gen->ReleaseModule();
+  if (!M) {
+    // The module has been released by IR gen on failures, do not
+    // double free.
+    TheModule = 0;
+    return;
+  }
+
+  assert(TheModule == M && "Unexpected module change during IR generation");
+
+  CreatePasses();
+  if (!AddEmitPasses())
+    return;
+
+  // Run passes. For now we do all passes at once, but eventually we
+  // would like to have the option of streaming code generation.
+
+  if (PerFunctionPasses) {
+    PrettyStackTraceString CrashInfo("Per-function optimization");
+
+    PerFunctionPasses->doInitialization();
+    for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
+      if (!I->isDeclaration())
+        PerFunctionPasses->run(*I);
+    PerFunctionPasses->doFinalization();
+  }
+
+  if (PerModulePasses) {
+    PrettyStackTraceString CrashInfo("Per-module optimization passes");
+    PerModulePasses->run(*M);
+  }
+
+  if (CodeGenPasses) {
+    PrettyStackTraceString CrashInfo("Code generation");
+    CodeGenPasses->doInitialization();
+    for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
+      if (!I->isDeclaration())
+        CodeGenPasses->run(*I);
+    CodeGenPasses->doFinalization();
+  }
+}
+
+ASTConsumer *clang::CreateBackendConsumer(BackendAction Action,
+                                          Diagnostic &Diags,
+                                          const LangOptions &LangOpts,
+                                          const CodeGenOptions &CodeGenOpts,
+                                          const TargetOptions &TargetOpts,
+                                          bool TimePasses,
+                                          const std::string& InFile,
+                                          llvm::raw_ostream* OS,
+                                          LLVMContext& C) {
+  return new BackendConsumer(Action, Diags, LangOpts, CodeGenOpts,
+                             TargetOpts, TimePasses, InFile, OS, C);
+}