Rebased PNaCl localmods in LLVM to 223109

tools/pnacl-llc/pnacl-llc.cpp

+//===-- pnacl-llc.cpp - PNaCl-specific llc: pexe ---> nexe  ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// pnacl-llc: the core of the PNaCl translator, compiling a pexe into a nexe.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Triple.h"
+#include "llvm/Analysis/NaCl.h"
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/CodeGen/CommandFlags.h"
+#include "llvm/CodeGen/LinkAllCodegenComponents.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/IRReader/IRReader.h"
+#include "llvm/MC/SubtargetFeature.h"
+#include "llvm/Pass.h"
+#include "llvm/PassManager.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DataStream.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/StreamingMemoryObject.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/Transforms/NaCl.h"
+
+#include "ThreadedFunctionQueue.h"
+#include "ThreadedStreamingCache.h"
+
+#include <pthread.h>
+#include <memory>
+
+using namespace llvm;
+
+// NOTE: When PNACL_BROWSER_TRANSLATOR is defined it means pnacl-llc is built
+// as a sandboxed translator (from pnacl-llc.pexe to pnacl-llc.nexe). In this
+// mode it uses SRPC operations instead of direct OS intefaces.
+#if defined(PNACL_BROWSER_TRANSLATOR)
+int srpc_main(int argc, char **argv);
+int getObjectFileFD(unsigned index);
+DataStreamer *getNaClBitcodeStreamer();
+
+fatal_error_handler_t getSRPCErrorHandler();
+#endif
+
+cl::opt<NaClFileFormat>
+InputFileFormat(
+    "bitcode-format",
+    cl::desc("Define format of input file:"),
+    cl::values(
+        clEnumValN(LLVMFormat, "llvm", "LLVM file (default)"),
+        clEnumValN(PNaClFormat, "pnacl", "PNaCl bitcode file"),
+        clEnumValEnd),
+#if defined(PNACL_BROWSER_TRANSLATOR)
+    cl::init(PNaClFormat)
+#else
+    cl::init(LLVMFormat)
+#endif
+                );
+
+// General options for llc.  Other pass-specific options are specified
+// within the corresponding llc passes, and target-specific options
+// and back-end code generation options are specified with the target machine.
+//
+static cl::opt<std::string>
+InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
+
+static cl::opt<std::string>
+OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
+
+// Using bitcode streaming allows compilation of one function at a time. This
+// allows earlier functions to be compiled before later functions are read from
+// the bitcode but of course means no whole-module optimizations. This means
+// that Module passes that run should only touch globals/function declarations
+// and not function bodies, otherwise the streaming and non-streaming code
+// pathes wouldn't emit the same code for each function. For now, streaming is
+// only supported for files and stdin.
+static cl::opt<bool>
+LazyBitcode("streaming-bitcode",
+  cl::desc("Use lazy bitcode streaming for file inputs"),
+  cl::init(false));
+
+static cl::opt<bool>
+PNaClABIVerify("pnaclabi-verify",
+  cl::desc("Verify PNaCl bitcode ABI before translating"),
+  cl::init(false));
+static cl::opt<bool>
+PNaClABIVerifyFatalErrors("pnaclabi-verify-fatal-errors",
+  cl::desc("PNaCl ABI verification errors are fatal"),
+  cl::init(false));
+
+
+static cl::opt<bool>
+NoIntegratedAssembler("no-integrated-as", cl::Hidden,
+                      cl::desc("Disable integrated assembler"));
+
+// Determine optimization level.
+static cl::opt<char>
+OptLevel("O",
+         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
+                  "(default = '-O2')"),
+         cl::Prefix,
+         cl::ZeroOrMore,
+         cl::init(' '));
+
+static cl::opt<std::string>
+UserDefinedTriple("mtriple", cl::desc("Set target triple"));
+
+static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
+                              cl::desc("Do not verify input module"));
+
+static cl::opt<bool>
+    DisableSimplifyLibCalls("disable-simplify-libcalls",
+                            cl::desc("Disable simplify-libcalls"));
+
+static cl::opt<unsigned>
+SplitModuleCount("split-module",
+                 cl::desc("Split PNaCl module"), cl::init(1U));
+
+enum SplitModuleSchedulerKind {
+  SplitModuleDynamic,
+  SplitModuleStatic
+};
+
+static cl::opt<SplitModuleSchedulerKind>
+SplitModuleSched(
+    "split-module-sched",
+    cl::desc("Choose thread scheduler for split module compilation."),
+    cl::values(
+        clEnumValN(SplitModuleDynamic, "dynamic",
+                   "Dynamic thread scheduling (default)"),
+        clEnumValN(SplitModuleStatic, "static",
+                   "Static thread scheduling"),
+        clEnumValEnd),
+    cl::init(SplitModuleDynamic));
+
+/// Compile the module provided to pnacl-llc. The file name for reading the
+/// module and other options are taken from globals populated by command-line
+/// option parsing.
+static int compileModule(StringRef ProgramName);
+
+#if !defined(PNACL_BROWSER_TRANSLATOR)
+// GetFileNameRoot - Helper function to get the basename of a filename.
+static std::string
+GetFileNameRoot(StringRef InputFilename) {
+  std::string IFN = InputFilename;
+  std::string outputFilename;
+  int Len = IFN.length();
+  if ((Len > 2) &&
+      IFN[Len-3] == '.' &&
+      ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
+       (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
+    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
+  } else {
+    outputFilename = IFN;
+  }
+  return outputFilename;
+}
+
+static tool_output_file *GetOutputStream(const char *TargetName,
+                                         Triple::OSType OS,
+                                         std::string Filename) {
+  // If we don't yet have an output filename, make one.
+  if (Filename.empty()) {
+    if (InputFilename == "-")
+      Filename = "-";
+    else {
+      Filename = GetFileNameRoot(InputFilename);
+
+      switch (FileType) {
+      case TargetMachine::CGFT_AssemblyFile:
+        if (TargetName[0] == 'c') {
+          if (TargetName[1] == 0)
+            Filename += ".cbe.c";
+          else if (TargetName[1] == 'p' && TargetName[2] == 'p')
+            Filename += ".cpp";
+          else
+            Filename += ".s";
+        } else
+          Filename += ".s";
+        break;
+      case TargetMachine::CGFT_ObjectFile:
+        if (OS == Triple::Win32)
+          Filename += ".obj";
+        else
+          Filename += ".o";
+        break;
+      case TargetMachine::CGFT_Null:
+        Filename += ".null";
+        break;
+      }
+    }
+  }
+
+  // Decide if we need "binary" output.
+  bool Binary = false;
+  switch (FileType) {
+  case TargetMachine::CGFT_AssemblyFile:
+    break;
+  case TargetMachine::CGFT_ObjectFile:
+  case TargetMachine::CGFT_Null:
+    Binary = true;
+    break;
+  }
+
+  // Open the file.
+  std::error_code EC;
+  sys::fs::OpenFlags OpenFlags = sys::fs::F_None;
+  if (!Binary)
+    OpenFlags |= sys::fs::F_Text;
+  tool_output_file *FDOut = new tool_output_file(Filename, EC, OpenFlags);
+  if (EC) {
+    errs() << EC.message() << '\n';
+    delete FDOut;
+    return nullptr;
+  }
+
+  return FDOut;
+}
+#endif // !defined(PNACL_BROWSER_TRANSLATOR)
+
+// main - Entry point for the llc compiler.
+//
+int llc_main(int argc, char **argv) {
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(argc, argv);
+
+  // Enable debug stream buffering.
+  EnableDebugBuffering = true;
+
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+
+#if defined(PNACL_BROWSER_TRANSLATOR)
+  install_fatal_error_handler(getSRPCErrorHandler(), nullptr);
+#endif
+
+  // Initialize targets first, so that --version shows registered targets.
+  InitializeAllTargets();
+  InitializeAllTargetMCs();
+  InitializeAllAsmPrinters();
+#if !defined(PNACL_BROWSER_TRANSLATOR)
+  // Prune asm parsing from sandboxed translator.
+  // Do not prune "AsmPrinters" because that includes
+  // the direct object emission.
+  InitializeAllAsmParsers();
+#endif
+
+  // Initialize codegen and IR passes used by pnacl-llc so that the -print-after,
+  // -print-before, and -stop-after options work.
+  PassRegistry *Registry = PassRegistry::getPassRegistry();
+  initializeCore(*Registry);
+  initializeCodeGen(*Registry);
+  initializeLoopStrengthReducePass(*Registry);
+  initializeLowerIntrinsicsPass(*Registry);
+  initializeUnreachableBlockElimPass(*Registry);
+
+  // Register the target printer for --version.
+  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
+
+  // Enable the PNaCl ABI verifier by default in sandboxed mode.
+#if defined(PNACL_BROWSER_TRANSLATOR)
+  PNaClABIVerify = true;
+  PNaClABIVerifyFatalErrors = true;
+#endif
+
+  cl::ParseCommandLineOptions(argc, argv, "pnacl-llc\n");
+
+#if defined(PNACL_BROWSER_TRANSLATOR)
+  // If the user explicitly requests LLVM format in sandboxed mode
+  // (where the default is PNaCl format), they probably want debug
+  // metadata enabled.
+  if (InputFileFormat == LLVMFormat) {
+    PNaClABIAllowDebugMetadata = true;
+  }
+#endif
+
+  if (SplitModuleCount > 1)
+    LLVMStartMultithreaded();
+
+  return compileModule(argv[0]);
+}
+
+static void CheckABIVerifyErrors(PNaClABIErrorReporter &Reporter,
+                                 const Twine &Name) {
+  if (PNaClABIVerify && Reporter.getErrorCount() > 0) {
+    std::string errors;
+    raw_string_ostream os(errors);
+    os << (PNaClABIVerifyFatalErrors ? "ERROR: " : "WARNING: ");
+    os << Name << " is not valid PNaCl bitcode:\n";
+    Reporter.printErrors(os);
+    if (PNaClABIVerifyFatalErrors) {
+      report_fatal_error(os.str());
+    }
+    errs() << os.str();
+  }
+  Reporter.reset();
+}
+
+static Module* getModule(StringRef ProgramName, LLVMContext &Context,
+                         StreamingMemoryObject *StreamingObject) {
+  std::unique_ptr<Module> M;
+  SMDiagnostic Err;
+  std::string VerboseBuffer;
+  raw_string_ostream VerboseStrm(VerboseBuffer);
+  if (LazyBitcode) {
+    std::string StrError;
+    switch (InputFileFormat) {
+    case PNaClFormat:
+      M.reset(getNaClStreamedBitcodeModule(
+          InputFilename,
+          new ThreadedStreamingCache(StreamingObject), Context, &VerboseStrm,
+          &StrError));
+      break;
+    case LLVMFormat:
+      M.reset(getStreamedBitcodeModule(
+          InputFilename,
+          new ThreadedStreamingCache(StreamingObject), Context, &StrError));
+      break;
+    case AutodetectFileFormat:
+      report_fatal_error("Command can't autodetect file format!");
+    }
+    if (!StrError.empty())
+      Err = SMDiagnostic(InputFilename, SourceMgr::DK_Error, StrError);
+  } else {
+#if defined(PNACL_BROWSER_TRANSLATOR)
+    llvm_unreachable("native client SRPC only supports streaming");
+#else
+    // Parses binary bitcode as well as textual assembly
+    // (so pulls in more code into pnacl-llc).
+    M = NaClParseIRFile(InputFilename, InputFileFormat, Err, &VerboseStrm,
+                        Context);
+#endif
+  }
+  if (!M) {
+#if defined(PNACL_BROWSER_TRANSLATOR)
+    report_fatal_error(VerboseStrm.str() + Err.getMessage());
+#else
+    // Err.print is prettier, so use it for the non-sandboxed translator.
+    Err.print(ProgramName.data(), errs());
+    errs() << VerboseStrm.str();
+    return nullptr;
+#endif
+  }
+  return M.release();
+}
+
+static cl::opt<bool>
+ExternalizeAll("externalize",
+               cl::desc("Externalize all symbols"),
+               cl::init(false));
+
+static int runCompilePasses(Module *mod,
+                            unsigned ModuleIndex,
+                            ThreadedFunctionQueue *FuncQueue,
+                            const Triple &TheTriple,
+                            TargetMachine &Target,
+                            StringRef ProgramName,
+                            formatted_raw_ostream &FOS){
+  PNaClABIErrorReporter ABIErrorReporter;
+
+  if (SplitModuleCount > 1 || ExternalizeAll) {
+    // Add function and global names, and give them external linkage.
+    // This relies on LLVM's consistent auto-generation of names, we could
+    // maybe do our own in case something changes there.
+    for (Module::iterator I = mod->begin(), E = mod->end(); I != E; ++I) {
+      if (!I->hasName())
+        I->setName("Function");
+      if (I->hasInternalLinkage())
+        I->setLinkage(GlobalValue::ExternalLinkage);
+    }
+    for (Module::global_iterator GI = mod->global_begin(),
+         GE = mod->global_end();
+         GI != GE; ++GI) {
+      if (!GI->hasName())
+        GI->setName("Global");
+      if (GI->hasInternalLinkage())
+        GI->setLinkage(GlobalValue::ExternalLinkage);
+    }
+    if (ModuleIndex > 0) {
+      // Remove the initializers for all global variables, turning them into
+      // declarations.
+      for (Module::global_iterator GI = mod->global_begin(),
+          GE = mod->global_end();
+          GI != GE; ++GI) {
+        assert(GI->hasInitializer() && "Global variable missing initializer");
+        Constant *Init = GI->getInitializer();
+        GI->setInitializer(nullptr);
+        if (Init->getNumUses() == 0)
+          Init->destroyConstant();
+      }
+    }
+  }
+
+  // Make all non-weak symbols hidden for better code. We cannot do
+  // this for weak symbols. The linker complains when some weak
+  // symbols are not resolved.
+  for (Module::iterator I = mod->begin(), E = mod->end(); I != E; ++I) {
+    if (!I->isWeakForLinker() && !I->hasLocalLinkage())
+      I->setVisibility(GlobalValue::HiddenVisibility);
+  }
+  for (Module::global_iterator GI = mod->global_begin(),
+           GE = mod->global_end();
+       GI != GE; ++GI) {
+    if (!GI->isWeakForLinker() && !GI->hasLocalLinkage())
+      GI->setVisibility(GlobalValue::HiddenVisibility);
+  }
+
+  // Build up all of the passes that we want to do to the module.
+  std::unique_ptr<PassManagerBase> PM;
+  if (LazyBitcode)
+    PM.reset(new FunctionPassManager(mod));
+  else
+    PM.reset(new PassManager());
+
+  // Add the target data from the target machine, if it exists, or the module.
+  if (const DataLayout *DL = Target.getSubtargetImpl()->getDataLayout())
+    mod->setDataLayout(DL);
+  PM->add(new DataLayoutPass());
+
+  // For conformance with llc, we let the user disable LLVM IR verification with
+  // -disable-verify. Unlike llc, when LLVM IR verification is enabled we only
+  // run it once, before PNaCl ABI verification.
+  if (!NoVerify)
+    PM->add(createVerifierPass());
+
+  // Add the ABI verifier pass before the analysis and code emission passes.
+  if (PNaClABIVerify)
+    PM->add(createPNaClABIVerifyFunctionsPass(&ABIErrorReporter));
+
+  // Add the intrinsic resolution pass. It assumes ABI-conformant code.
+  PM->add(createResolvePNaClIntrinsicsPass());
+
+  // Add an appropriate TargetLibraryInfo pass for the module's triple.
+  TargetLibraryInfo *TLI = new TargetLibraryInfo(TheTriple);
+  if (DisableSimplifyLibCalls)
+    TLI->disableAllFunctions();
+  PM->add(TLI);
+
+  // Allow subsequent passes and the backend to better optimize instructions
+  // that were simplified for PNaCl's ABI. This pass uses the TargetLibraryInfo
+  // above.
+  PM->add(createBackendCanonicalizePass());
+
+  // Add internal analysis passes from the target machine.
+  Target.addAnalysisPasses(*PM);
+
+  // Ask the target to add backend passes as necessary. We explicitly ask it
+  // not to add the verifier pass because we added it earlier.
+  if (Target.addPassesToEmitFile(*PM, FOS, FileType,
+                                 /* DisableVerify */ true)) {
+    errs() << ProgramName
+    << ": target does not support generation of this file type!\n";
+    return 1;
+  }
+
+  if (LazyBitcode) {
+    auto FPM = static_cast<FunctionPassManager *>(PM.get());
+    FPM->doInitialization();
+    unsigned FuncIndex = 0;
+    switch (SplitModuleSched) {
+    case SplitModuleStatic:
+      for (Module::iterator I = mod->begin(), E = mod->end(); I != E; ++I) {
+        if (FuncQueue->GrabFunctionStatic(FuncIndex, ModuleIndex)) {
+          FPM->run(*I);
+          CheckABIVerifyErrors(ABIErrorReporter, "Function " + I->getName());
+          I->Dematerialize();
+        }
+        ++FuncIndex;
+      }
+      break;
+    case SplitModuleDynamic:
+      unsigned ChunkSize = 0;
+      unsigned NumFunctions = FuncQueue->Size();
+      Module::iterator I = mod->begin();
+      while (FuncIndex < NumFunctions) {
+        ChunkSize = FuncQueue->RecommendedChunkSize();
+        unsigned NextIndex;
+        bool grabbed = FuncQueue->GrabFunctionDynamic(FuncIndex, ChunkSize,
+                                                      NextIndex);
+        if (grabbed) {
+          while (FuncIndex < NextIndex) {
+            if (!I->isMaterializable() && I->isDeclaration()) {
+              ++I;
+              continue;
+            }
+            FPM->run(*I);
+            CheckABIVerifyErrors(ABIErrorReporter, "Function " + I->getName());
+            I->Dematerialize();
+            ++FuncIndex;
+            ++I;
+          }
+        } else {
+          while (FuncIndex < NextIndex) {
+            if (!I->isMaterializable() && I->isDeclaration()) {
+              ++I;
+              continue;
+            }
+            ++FuncIndex;
+            ++I;
+          }
+        }
+      }
+      break;
+    }
+    FPM->doFinalization();
+  } else
+    static_cast<PassManager *>(PM.get())->run(*mod);
+
+  return 0;
+}
+
+static int compileSplitModule(const TargetOptions &Options,
+                              const Triple &TheTriple,
+                              const Target *TheTarget,
+                              const std::string &FeaturesStr,
+                              CodeGenOpt::Level OLvl,
+                              const StringRef &ProgramName,
+                              Module *GlobalModule,
+                              StreamingMemoryObject *StreamingObject,
+                              unsigned ModuleIndex,
+                              ThreadedFunctionQueue *FuncQueue) {
+  std::auto_ptr<TargetMachine>
+    target(TheTarget->createTargetMachine(TheTriple.getTriple(),
+                                          MCPU, FeaturesStr, Options,
+                                          RelocModel, CMModel, OLvl));
+  assert(target.get() && "Could not allocate target machine!");
+  TargetMachine &Target = *target.get();
+  // Override default to generate verbose assembly.
+  Target.setAsmVerbosityDefault(true);
+  if (RelaxAll.getNumOccurrences() > 0 &&
+      FileType != TargetMachine::CGFT_ObjectFile)
+    errs() << ProgramName
+             << ": warning: ignoring -mc-relax-all because filetype != obj";
+  // The OwningPtrs are only used if we are not the primary module.
+  std::unique_ptr<LLVMContext> C;
+  std::unique_ptr<Module> M;
+  Module *mod(nullptr);
+
+  if (ModuleIndex == 0) {
+    mod = GlobalModule;
+  } else {
+    C.reset(new LLVMContext());
+    mod = getModule(ProgramName, *C, StreamingObject);
+    if (!mod)
+      return 1;
+    M.reset(mod);
+
+    // Add declarations for external functions required by PNaCl. The
+    // ResolvePNaClIntrinsics function pass running during streaming
+    // depends on these declarations being in the module.
+    std::unique_ptr<ModulePass> AddPNaClExternalDeclsPass(
+        createAddPNaClExternalDeclsPass());
+    AddPNaClExternalDeclsPass->runOnModule(*M);
+    AddPNaClExternalDeclsPass.reset();
+  }
+
+  mod->setTargetTriple(Triple::normalize(UserDefinedTriple));
+
+  {
+#if !defined(PNACL_BROWSER_TRANSLATOR)
+      // Figure out where we are going to send the output.
+    std::string N(OutputFilename);
+    raw_string_ostream OutFileName(N);
+    if (ModuleIndex > 0)
+      OutFileName << ".module" << ModuleIndex;
+    std::unique_ptr<tool_output_file> Out
+        (GetOutputStream(TheTarget->getName(), TheTriple.getOS(),
+                         OutFileName.str()));
+    if (!Out) return 1;
+    formatted_raw_ostream FOS(Out->os());
+#else
+    raw_fd_ostream ROS(getObjectFileFD(ModuleIndex), /* ShouldClose */ true);
+    ROS.SetBufferSize(1 << 20);
+    formatted_raw_ostream FOS(ROS);
+#endif
+    int ret = runCompilePasses(mod, ModuleIndex, FuncQueue,
+                               TheTriple, Target, ProgramName,
+                               FOS);
+    if (ret)
+      return ret;
+#if defined(PNACL_BROWSER_TRANSLATOR)
+    FOS.flush();
+    ROS.flush();
+#else
+    // Declare success.
+    Out->keep();
+#endif // PNACL_BROWSER_TRANSLATOR
+  }
+  return 0;
+}
+
+struct ThreadData {
+  const TargetOptions *Options;
+  const Triple *TheTriple;
+  const Target *TheTarget;
+  std::string FeaturesStr;
+  CodeGenOpt::Level OLvl;
+  std::string ProgramName;
+  Module *GlobalModule;
+  StreamingMemoryObject *StreamingObject;
+  unsigned ModuleIndex;
+  ThreadedFunctionQueue *FuncQueue;
+};
+
+
+static void *runCompileThread(void *arg) {
+  struct ThreadData *Data = static_cast<ThreadData *>(arg);
+  int ret = compileSplitModule(*Data->Options,
+                               *Data->TheTriple,
+                               Data->TheTarget,
+                               Data->FeaturesStr,
+                               Data->OLvl,
+                               Data->ProgramName,
+                               Data->GlobalModule,
+                               Data->StreamingObject,
+                               Data->ModuleIndex,
+                               Data->FuncQueue);
+  return reinterpret_cast<void *>(static_cast<intptr_t>(ret));
+}
+
+static int compileModule(StringRef ProgramName) {
+  // Use a new context instead of the global context for the main module. It must
+  // outlive the module object, declared below. We do this because
+  // lib/CodeGen/PseudoSourceValue.cpp gets a type from the global context and
+  // races with any other use of the context. Rather than doing an invasive
+  // plumbing change to fix it, we work around it by using a new context here
+  // and leaving PseudoSourceValue as the only user of the global context.
+  std::unique_ptr<LLVMContext> MainContext(new LLVMContext());
+  std::unique_ptr<Module> mod;
+  Triple TheTriple;
+  PNaClABIErrorReporter ABIErrorReporter;
+  std::unique_ptr<StreamingMemoryObject> StreamingObject;
+
+  if (!MainContext) return 1;
+
+#if defined(PNACL_BROWSER_TRANSLATOR)
+  StreamingObject.reset(
+      new StreamingMemoryObjectImpl(getNaClBitcodeStreamer()));
+#else
+  if (LazyBitcode) {
+    std::string StrError;
+    DataStreamer* FileStreamer(getDataFileStreamer(InputFilename, &StrError));
+    if (!StrError.empty()) {
+      SMDiagnostic Err(InputFilename, SourceMgr::DK_Error, StrError);
+      Err.print(ProgramName.data(), errs());
+    }
+    if (!FileStreamer)
+      return 1;
+    StreamingObject.reset(new StreamingMemoryObjectImpl(FileStreamer));
+  }
+#endif
+  mod.reset(getModule(ProgramName, *MainContext.get(), StreamingObject.get()));
+
+  if (!mod) return 1;
+
+  if (PNaClABIVerify) {
+    // Verify the module (but not the functions yet)
+    std::unique_ptr<ModulePass> VerifyPass(
+        createPNaClABIVerifyModulePass(&ABIErrorReporter, LazyBitcode));
+    VerifyPass->runOnModule(*mod);
+    CheckABIVerifyErrors(ABIErrorReporter, "Module");
+    VerifyPass.reset();
+  }
+
+  // Add declarations for external functions required by PNaCl. The
+  // ResolvePNaClIntrinsics function pass running during streaming
+  // depends on these declarations being in the module.
+  std::unique_ptr<ModulePass> AddPNaClExternalDeclsPass(
+      createAddPNaClExternalDeclsPass());
+  AddPNaClExternalDeclsPass->runOnModule(*mod);
+  AddPNaClExternalDeclsPass.reset();
+
+  if (UserDefinedTriple.empty()) {
+    report_fatal_error("-mtriple must be set to a target triple for pnacl-llc");
+  } else {
+    mod->setTargetTriple(Triple::normalize(UserDefinedTriple));
+    TheTriple = Triple(mod->getTargetTriple());
+  }
+
+  // Get the target specific parser.
+  std::string Error;
+  const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
+                                                         Error);
+  if (!TheTarget) {
+    errs() << ProgramName << ": " << Error;
+    return 1;
+  }
+
+  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
+  Options.DisableIntegratedAS = NoIntegratedAssembler;
+
+  if (GenerateSoftFloatCalls)
+    FloatABIForCalls = FloatABI::Soft;
+
+  // Package up features to be passed to target/subtarget
+  std::string FeaturesStr;
+  if (MAttrs.size()) {
+    SubtargetFeatures Features;
+    for (unsigned i = 0; i != MAttrs.size(); ++i)
+      Features.AddFeature(MAttrs[i]);
+    FeaturesStr = Features.getString();
+  }
+
+  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
+  switch (OptLevel) {
+  default:
+    errs() << ProgramName << ": invalid optimization level.\n";
+    return 1;
+  case ' ': break;
+  case '0': OLvl = CodeGenOpt::None; break;
+  case '1': OLvl = CodeGenOpt::Less; break;
+  case '2': OLvl = CodeGenOpt::Default; break;
+  case '3': OLvl = CodeGenOpt::Aggressive; break;
+  }
+
+  SmallVector<pthread_t, 4> Pthreads(SplitModuleCount);
+  SmallVector<ThreadData, 4> ThreadDatas(SplitModuleCount);
+  ThreadedFunctionQueue FuncQueue(mod.get(), SplitModuleCount);
+
+  if (SplitModuleCount == 1) {
+    // No need for dynamic scheduling with one thread.
+    SplitModuleSched = SplitModuleStatic;
+    return compileSplitModule(Options, TheTriple, TheTarget, FeaturesStr,
+                              OLvl, ProgramName, mod.get(), nullptr, 0,
+                              &FuncQueue);
+  }
+
+  for(unsigned ModuleIndex = 0; ModuleIndex < SplitModuleCount; ++ModuleIndex) {
+    ThreadDatas[ModuleIndex].Options = &Options;
+    ThreadDatas[ModuleIndex].TheTriple = &TheTriple;
+    ThreadDatas[ModuleIndex].TheTarget = TheTarget;
+    ThreadDatas[ModuleIndex].FeaturesStr = FeaturesStr;
+    ThreadDatas[ModuleIndex].OLvl = OLvl;
+    ThreadDatas[ModuleIndex].ProgramName = ProgramName.str();
+    ThreadDatas[ModuleIndex].GlobalModule = mod.get();
+    ThreadDatas[ModuleIndex].StreamingObject = StreamingObject.get();
+    ThreadDatas[ModuleIndex].ModuleIndex = ModuleIndex;
+    ThreadDatas[ModuleIndex].FuncQueue = &FuncQueue;
+    if (pthread_create(&Pthreads[ModuleIndex], nullptr, runCompileThread,
+                        &ThreadDatas[ModuleIndex])) {
+      report_fatal_error("Failed to create thread");
+    }
+  }
+  for(unsigned ModuleIndex = 0; ModuleIndex < SplitModuleCount; ++ModuleIndex) {
+    void *retval;
+    if (pthread_join(Pthreads[ModuleIndex], &retval))
+      report_fatal_error("Failed to join thread");
+    intptr_t ret = reinterpret_cast<intptr_t>(retval);
+    if (ret != 0)
+      report_fatal_error("Thread returned nonzero");
+  }
+  return 0;
+}
+
+int main(int argc, char **argv) {
+#if defined(PNACL_BROWSER_TRANSLATOR)
+  return srpc_main(argc, argv);
+#else
+  return llc_main(argc, argv);
+#endif // PNACL_BROWSER_TRANSLATOR
+}