--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/lib/ExecutionEngine/ExecutionEngine.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,1309 @@
+//===-- ExecutionEngine.cpp - Common Implementation shared by EEs ---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the common interface used by the various execution engine
+// subclasses.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ExecutionEngine/JITEventListener.h"
+#include "llvm/ExecutionEngine/ObjectCache.h"
+#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Mangler.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/Object/Archive.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
+#include <cmath>
+#include <cstring>
+#include <mutex>
+using namespace llvm;
+
+#define DEBUG_TYPE "jit"
+
+STATISTIC(NumInitBytes, "Number of bytes of global vars initialized");
+STATISTIC(NumGlobals  , "Number of global vars initialized");
+
+ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
+    std::unique_ptr<Module> M, std::string *ErrorStr,
+    std::shared_ptr<MCJITMemoryManager> MemMgr,
+    std::shared_ptr<LegacyJITSymbolResolver> Resolver,
+    std::unique_ptr<TargetMachine> TM) = nullptr;
+
+ExecutionEngine *(*ExecutionEngine::OrcMCJITReplacementCtor)(
+    std::string *ErrorStr, std::shared_ptr<MCJITMemoryManager> MemMgr,
+    std::shared_ptr<LegacyJITSymbolResolver> Resolver,
+    std::unique_ptr<TargetMachine> TM) = nullptr;
+
+ExecutionEngine *(*ExecutionEngine::InterpCtor)(std::unique_ptr<Module> M,
+                                                std::string *ErrorStr) =nullptr;
+
+void JITEventListener::anchor() {}
+
+void ObjectCache::anchor() {}
+
+void ExecutionEngine::Init(std::unique_ptr<Module> M) {
+  CompilingLazily         = false;
+  GVCompilationDisabled   = false;
+  SymbolSearchingDisabled = false;
+
+  // IR module verification is enabled by default in debug builds, and disabled
+  // by default in release builds.
+#ifndef NDEBUG
+  VerifyModules = true;
+#else
+  VerifyModules = false;
+#endif
+
+  assert(M && "Module is null?");
+  Modules.push_back(std::move(M));
+}
+
+ExecutionEngine::ExecutionEngine(std::unique_ptr<Module> M)
+    : DL(M->getDataLayout()), LazyFunctionCreator(nullptr) {
+  Init(std::move(M));
+}
+
+ExecutionEngine::ExecutionEngine(DataLayout DL, std::unique_ptr<Module> M)
+    : DL(std::move(DL)), LazyFunctionCreator(nullptr) {
+  Init(std::move(M));
+}
+
+ExecutionEngine::~ExecutionEngine() {
+  clearAllGlobalMappings();
+}
+
+namespace {
+/// Helper class which uses a value handler to automatically deletes the
+/// memory block when the GlobalVariable is destroyed.
+class GVMemoryBlock final : public CallbackVH {
+  GVMemoryBlock(const GlobalVariable *GV)
+    : CallbackVH(const_cast<GlobalVariable*>(GV)) {}
+
+public:
+  /// Returns the address the GlobalVariable should be written into.  The
+  /// GVMemoryBlock object prefixes that.
+  static char *Create(const GlobalVariable *GV, const DataLayout& TD) {
+    Type *ElTy = GV->getValueType();
+    size_t GVSize = (size_t)TD.getTypeAllocSize(ElTy);
+    void *RawMemory = ::operator new(
+        alignTo(sizeof(GVMemoryBlock), TD.getPreferredAlignment(GV)) + GVSize);
+    new(RawMemory) GVMemoryBlock(GV);
+    return static_cast<char*>(RawMemory) + sizeof(GVMemoryBlock);
+  }
+
+  void deleted() override {
+    // We allocated with operator new and with some extra memory hanging off the
+    // end, so don't just delete this.  I'm not sure if this is actually
+    // required.
+    this->~GVMemoryBlock();
+    ::operator delete(this);
+  }
+};
+}  // anonymous namespace
+
+char *ExecutionEngine::getMemoryForGV(const GlobalVariable *GV) {
+  return GVMemoryBlock::Create(GV, getDataLayout());
+}
+
+void ExecutionEngine::addObjectFile(std::unique_ptr<object::ObjectFile> O) {
+  llvm_unreachable("ExecutionEngine subclass doesn't implement addObjectFile.");
+}
+
+void
+ExecutionEngine::addObjectFile(object::OwningBinary<object::ObjectFile> O) {
+  llvm_unreachable("ExecutionEngine subclass doesn't implement addObjectFile.");
+}
+
+void ExecutionEngine::addArchive(object::OwningBinary<object::Archive> A) {
+  llvm_unreachable("ExecutionEngine subclass doesn't implement addArchive.");
+}
+
+bool ExecutionEngine::removeModule(Module *M) {
+  for (auto I = Modules.begin(), E = Modules.end(); I != E; ++I) {
+    Module *Found = I->get();
+    if (Found == M) {
+      I->release();
+      Modules.erase(I);
+      clearGlobalMappingsFromModule(M);
+      return true;
+    }
+  }
+  return false;
+}
+
+Function *ExecutionEngine::FindFunctionNamed(StringRef FnName) {
+  for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
+    Function *F = Modules[i]->getFunction(FnName);
+    if (F && !F->isDeclaration())
+      return F;
+  }
+  return nullptr;
+}
+
+GlobalVariable *ExecutionEngine::FindGlobalVariableNamed(StringRef Name, bool AllowInternal) {
+  for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
+    GlobalVariable *GV = Modules[i]->getGlobalVariable(Name,AllowInternal);
+    if (GV && !GV->isDeclaration())
+      return GV;
+  }
+  return nullptr;
+}
+
+uint64_t ExecutionEngineState::RemoveMapping(StringRef Name) {
+  GlobalAddressMapTy::iterator I = GlobalAddressMap.find(Name);
+  uint64_t OldVal;
+
+  // FIXME: This is silly, we shouldn't end up with a mapping -> 0 in the
+  // GlobalAddressMap.
+  if (I == GlobalAddressMap.end())
+    OldVal = 0;
+  else {
+    GlobalAddressReverseMap.erase(I->second);
+    OldVal = I->second;
+    GlobalAddressMap.erase(I);
+  }
+
+  return OldVal;
+}
+
+std::string ExecutionEngine::getMangledName(const GlobalValue *GV) {
+  assert(GV->hasName() && "Global must have name.");
+
+  std::lock_guard<sys::Mutex> locked(lock);
+  SmallString<128> FullName;
+
+  const DataLayout &DL =
+    GV->getParent()->getDataLayout().isDefault()
+      ? getDataLayout()
+      : GV->getParent()->getDataLayout();
+
+  Mangler::getNameWithPrefix(FullName, GV->getName(), DL);
+  return std::string(FullName.str());
+}
+
+void ExecutionEngine::addGlobalMapping(const GlobalValue *GV, void *Addr) {
+  std::lock_guard<sys::Mutex> locked(lock);
+  addGlobalMapping(getMangledName(GV), (uint64_t) Addr);
+}
+
+void ExecutionEngine::addGlobalMapping(StringRef Name, uint64_t Addr) {
+  std::lock_guard<sys::Mutex> locked(lock);
+
+  assert(!Name.empty() && "Empty GlobalMapping symbol name!");
+
+  LLVM_DEBUG(dbgs() << "JIT: Map \'" << Name << "\' to [" << Addr << "]\n";);
+  uint64_t &CurVal = EEState.getGlobalAddressMap()[Name];
+  assert((!CurVal || !Addr) && "GlobalMapping already established!");
+  CurVal = Addr;
+
+  // If we are using the reverse mapping, add it too.
+  if (!EEState.getGlobalAddressReverseMap().empty()) {
+    std::string &V = EEState.getGlobalAddressReverseMap()[CurVal];
+    assert((!V.empty() || !Name.empty()) &&
+           "GlobalMapping already established!");
+    V = std::string(Name);
+  }
+}
+
+void ExecutionEngine::clearAllGlobalMappings() {
+  std::lock_guard<sys::Mutex> locked(lock);
+
+  EEState.getGlobalAddressMap().clear();
+  EEState.getGlobalAddressReverseMap().clear();
+}
+
+void ExecutionEngine::clearGlobalMappingsFromModule(Module *M) {
+  std::lock_guard<sys::Mutex> locked(lock);
+
+  for (GlobalObject &GO : M->global_objects())
+    EEState.RemoveMapping(getMangledName(&GO));
+}
+
+uint64_t ExecutionEngine::updateGlobalMapping(const GlobalValue *GV,
+                                              void *Addr) {
+  std::lock_guard<sys::Mutex> locked(lock);
+  return updateGlobalMapping(getMangledName(GV), (uint64_t) Addr);
+}
+
+uint64_t ExecutionEngine::updateGlobalMapping(StringRef Name, uint64_t Addr) {
+  std::lock_guard<sys::Mutex> locked(lock);
+
+  ExecutionEngineState::GlobalAddressMapTy &Map =
+    EEState.getGlobalAddressMap();
+
+  // Deleting from the mapping?
+  if (!Addr)
+    return EEState.RemoveMapping(Name);
+
+  uint64_t &CurVal = Map[Name];
+  uint64_t OldVal = CurVal;
+
+  if (CurVal && !EEState.getGlobalAddressReverseMap().empty())
+    EEState.getGlobalAddressReverseMap().erase(CurVal);
+  CurVal = Addr;
+
+  // If we are using the reverse mapping, add it too.
+  if (!EEState.getGlobalAddressReverseMap().empty()) {
+    std::string &V = EEState.getGlobalAddressReverseMap()[CurVal];
+    assert((!V.empty() || !Name.empty()) &&
+           "GlobalMapping already established!");
+    V = std::string(Name);
+  }
+  return OldVal;
+}
+
+uint64_t ExecutionEngine::getAddressToGlobalIfAvailable(StringRef S) {
+  std::lock_guard<sys::Mutex> locked(lock);
+  uint64_t Address = 0;
+  ExecutionEngineState::GlobalAddressMapTy::iterator I =
+    EEState.getGlobalAddressMap().find(S);
+  if (I != EEState.getGlobalAddressMap().end())
+    Address = I->second;
+  return Address;
+}
+
+
+void *ExecutionEngine::getPointerToGlobalIfAvailable(StringRef S) {
+  std::lock_guard<sys::Mutex> locked(lock);
+  if (void* Address = (void *) getAddressToGlobalIfAvailable(S))
+    return Address;
+  return nullptr;
+}
+
+void *ExecutionEngine::getPointerToGlobalIfAvailable(const GlobalValue *GV) {
+  std::lock_guard<sys::Mutex> locked(lock);
+  return getPointerToGlobalIfAvailable(getMangledName(GV));
+}
+
+const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
+  std::lock_guard<sys::Mutex> locked(lock);
+
+  // If we haven't computed the reverse mapping yet, do so first.
+  if (EEState.getGlobalAddressReverseMap().empty()) {
+    for (ExecutionEngineState::GlobalAddressMapTy::iterator
+           I = EEState.getGlobalAddressMap().begin(),
+           E = EEState.getGlobalAddressMap().end(); I != E; ++I) {
+      StringRef Name = I->first();
+      uint64_t Addr = I->second;
+      EEState.getGlobalAddressReverseMap().insert(
+          std::make_pair(Addr, std::string(Name)));
+    }
+  }
+
+  std::map<uint64_t, std::string>::iterator I =
+    EEState.getGlobalAddressReverseMap().find((uint64_t) Addr);
+
+  if (I != EEState.getGlobalAddressReverseMap().end()) {
+    StringRef Name = I->second;
+    for (unsigned i = 0, e = Modules.size(); i != e; ++i)
+      if (GlobalValue *GV = Modules[i]->getNamedValue(Name))
+        return GV;
+  }
+  return nullptr;
+}
+
+namespace {
+class ArgvArray {
+  std::unique_ptr<char[]> Array;
+  std::vector<std::unique_ptr<char[]>> Values;
+public:
+  /// Turn a vector of strings into a nice argv style array of pointers to null
+  /// terminated strings.
+  void *reset(LLVMContext &C, ExecutionEngine *EE,
+              const std::vector<std::string> &InputArgv);
+};
+}  // anonymous namespace
+void *ArgvArray::reset(LLVMContext &C, ExecutionEngine *EE,
+                       const std::vector<std::string> &InputArgv) {
+  Values.clear();  // Free the old contents.
+  Values.reserve(InputArgv.size());
+  unsigned PtrSize = EE->getDataLayout().getPointerSize();
+  Array = std::make_unique<char[]>((InputArgv.size()+1)*PtrSize);
+
+  LLVM_DEBUG(dbgs() << "JIT: ARGV = " << (void *)Array.get() << "\n");
+  Type *SBytePtr = Type::getInt8PtrTy(C);
+
+  for (unsigned i = 0; i != InputArgv.size(); ++i) {
+    unsigned Size = InputArgv[i].size()+1;
+    auto Dest = std::make_unique<char[]>(Size);
+    LLVM_DEBUG(dbgs() << "JIT: ARGV[" << i << "] = " << (void *)Dest.get()
+                      << "\n");
+
+    std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest.get());
+    Dest[Size-1] = 0;
+
+    // Endian safe: Array[i] = (PointerTy)Dest;
+    EE->StoreValueToMemory(PTOGV(Dest.get()),
+                           (GenericValue*)(&Array[i*PtrSize]), SBytePtr);
+    Values.push_back(std::move(Dest));
+  }
+
+  // Null terminate it
+  EE->StoreValueToMemory(PTOGV(nullptr),
+                         (GenericValue*)(&Array[InputArgv.size()*PtrSize]),
+                         SBytePtr);
+  return Array.get();
+}
+
+void ExecutionEngine::runStaticConstructorsDestructors(Module &module,
+                                                       bool isDtors) {
+  StringRef Name(isDtors ? "llvm.global_dtors" : "llvm.global_ctors");
+  GlobalVariable *GV = module.getNamedGlobal(Name);
+
+  // If this global has internal linkage, or if it has a use, then it must be
+  // an old-style (llvmgcc3) static ctor with __main linked in and in use.  If
+  // this is the case, don't execute any of the global ctors, __main will do
+  // it.
+  if (!GV || GV->isDeclaration() || GV->hasLocalLinkage()) return;
+
+  // Should be an array of '{ i32, void ()* }' structs.  The first value is
+  // the init priority, which we ignore.
+  ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
+  if (!InitList)
+    return;
+  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+    ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i));
+    if (!CS) continue;
+
+    Constant *FP = CS->getOperand(1);
+    if (FP->isNullValue())
+      continue;  // Found a sentinal value, ignore.
+
+    // Strip off constant expression casts.
+    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
+      if (CE->isCast())
+        FP = CE->getOperand(0);
+
+    // Execute the ctor/dtor function!
+    if (Function *F = dyn_cast<Function>(FP))
+      runFunction(F, None);
+
+    // FIXME: It is marginally lame that we just do nothing here if we see an
+    // entry we don't recognize. It might not be unreasonable for the verifier
+    // to not even allow this and just assert here.
+  }
+}
+
+void ExecutionEngine::runStaticConstructorsDestructors(bool isDtors) {
+  // Execute global ctors/dtors for each module in the program.
+  for (std::unique_ptr<Module> &M : Modules)
+    runStaticConstructorsDestructors(*M, isDtors);
+}
+
+#ifndef NDEBUG
+/// isTargetNullPtr - Return whether the target pointer stored at Loc is null.
+static bool isTargetNullPtr(ExecutionEngine *EE, void *Loc) {
+  unsigned PtrSize = EE->getDataLayout().getPointerSize();
+  for (unsigned i = 0; i < PtrSize; ++i)
+    if (*(i + (uint8_t*)Loc))
+      return false;
+  return true;
+}
+#endif
+
+int ExecutionEngine::runFunctionAsMain(Function *Fn,
+                                       const std::vector<std::string> &argv,
+                                       const char * const * envp) {
+  std::vector<GenericValue> GVArgs;
+  GenericValue GVArgc;
+  GVArgc.IntVal = APInt(32, argv.size());
+
+  // Check main() type
+  unsigned NumArgs = Fn->getFunctionType()->getNumParams();
+  FunctionType *FTy = Fn->getFunctionType();
+  Type* PPInt8Ty = Type::getInt8PtrTy(Fn->getContext())->getPointerTo();
+
+  // Check the argument types.
+  if (NumArgs > 3)
+    report_fatal_error("Invalid number of arguments of main() supplied");
+  if (NumArgs >= 3 && FTy->getParamType(2) != PPInt8Ty)
+    report_fatal_error("Invalid type for third argument of main() supplied");
+  if (NumArgs >= 2 && FTy->getParamType(1) != PPInt8Ty)
+    report_fatal_error("Invalid type for second argument of main() supplied");
+  if (NumArgs >= 1 && !FTy->getParamType(0)->isIntegerTy(32))
+    report_fatal_error("Invalid type for first argument of main() supplied");
+  if (!FTy->getReturnType()->isIntegerTy() &&
+      !FTy->getReturnType()->isVoidTy())
+    report_fatal_error("Invalid return type of main() supplied");
+
+  ArgvArray CArgv;
+  ArgvArray CEnv;
+  if (NumArgs) {
+    GVArgs.push_back(GVArgc); // Arg #0 = argc.
+    if (NumArgs > 1) {
+      // Arg #1 = argv.
+      GVArgs.push_back(PTOGV(CArgv.reset(Fn->getContext(), this, argv)));
+      assert(!isTargetNullPtr(this, GVTOP(GVArgs[1])) &&
+             "argv[0] was null after CreateArgv");
+      if (NumArgs > 2) {
+        std::vector<std::string> EnvVars;
+        for (unsigned i = 0; envp[i]; ++i)
+          EnvVars.emplace_back(envp[i]);
+        // Arg #2 = envp.
+        GVArgs.push_back(PTOGV(CEnv.reset(Fn->getContext(), this, EnvVars)));
+      }
+    }
+  }
+
+  return runFunction(Fn, GVArgs).IntVal.getZExtValue();
+}
+
+EngineBuilder::EngineBuilder() : EngineBuilder(nullptr) {}
+
+EngineBuilder::EngineBuilder(std::unique_ptr<Module> M)
+    : M(std::move(M)), WhichEngine(EngineKind::Either), ErrorStr(nullptr),
+      OptLevel(CodeGenOpt::Default), MemMgr(nullptr), Resolver(nullptr),
+      UseOrcMCJITReplacement(false) {
+// IR module verification is enabled by default in debug builds, and disabled
+// by default in release builds.
+#ifndef NDEBUG
+  VerifyModules = true;
+#else
+  VerifyModules = false;
+#endif
+}
+
+EngineBuilder::~EngineBuilder() = default;
+
+EngineBuilder &EngineBuilder::setMCJITMemoryManager(
+                                   std::unique_ptr<RTDyldMemoryManager> mcjmm) {
+  auto SharedMM = std::shared_ptr<RTDyldMemoryManager>(std::move(mcjmm));
+  MemMgr = SharedMM;
+  Resolver = SharedMM;
+  return *this;
+}
+
+EngineBuilder&
+EngineBuilder::setMemoryManager(std::unique_ptr<MCJITMemoryManager> MM) {
+  MemMgr = std::shared_ptr<MCJITMemoryManager>(std::move(MM));
+  return *this;
+}
+
+EngineBuilder &
+EngineBuilder::setSymbolResolver(std::unique_ptr<LegacyJITSymbolResolver> SR) {
+  Resolver = std::shared_ptr<LegacyJITSymbolResolver>(std::move(SR));
+  return *this;
+}
+
+ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
+  std::unique_ptr<TargetMachine> TheTM(TM); // Take ownership.
+
+  // Make sure we can resolve symbols in the program as well. The zero arg
+  // to the function tells DynamicLibrary to load the program, not a library.
+  if (sys::DynamicLibrary::LoadLibraryPermanently(nullptr, ErrorStr))
+    return nullptr;
+
+  // If the user specified a memory manager but didn't specify which engine to
+  // create, we assume they only want the JIT, and we fail if they only want
+  // the interpreter.
+  if (MemMgr) {
+    if (WhichEngine & EngineKind::JIT)
+      WhichEngine = EngineKind::JIT;
+    else {
+      if (ErrorStr)
+        *ErrorStr = "Cannot create an interpreter with a memory manager.";
+      return nullptr;
+    }
+  }
+
+  // Unless the interpreter was explicitly selected or the JIT is not linked,
+  // try making a JIT.
+  if ((WhichEngine & EngineKind::JIT) && TheTM) {
+    if (!TM->getTarget().hasJIT()) {
+      errs() << "WARNING: This target JIT is not designed for the host"
+             << " you are running.  If bad things happen, please choose"
+             << " a different -march switch.\n";
+    }
+
+    ExecutionEngine *EE = nullptr;
+    if (ExecutionEngine::OrcMCJITReplacementCtor && UseOrcMCJITReplacement) {
+      EE = ExecutionEngine::OrcMCJITReplacementCtor(ErrorStr, std::move(MemMgr),
+                                                    std::move(Resolver),
+                                                    std::move(TheTM));
+      EE->addModule(std::move(M));
+    } else if (ExecutionEngine::MCJITCtor)
+      EE = ExecutionEngine::MCJITCtor(std::move(M), ErrorStr, std::move(MemMgr),
+                                      std::move(Resolver), std::move(TheTM));
+
+    if (EE) {
+      EE->setVerifyModules(VerifyModules);
+      return EE;
+    }
+  }
+
+  // If we can't make a JIT and we didn't request one specifically, try making
+  // an interpreter instead.
+  if (WhichEngine & EngineKind::Interpreter) {
+    if (ExecutionEngine::InterpCtor)
+      return ExecutionEngine::InterpCtor(std::move(M), ErrorStr);
+    if (ErrorStr)
+      *ErrorStr = "Interpreter has not been linked in.";
+    return nullptr;
+  }
+
+  if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::MCJITCtor) {
+    if (ErrorStr)
+      *ErrorStr = "JIT has not been linked in.";
+  }
+
+  return nullptr;
+}
+
+void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
+  if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
+    return getPointerToFunction(F);
+
+  std::lock_guard<sys::Mutex> locked(lock);
+  if (void* P = getPointerToGlobalIfAvailable(GV))
+    return P;
+
+  // Global variable might have been added since interpreter started.
+  if (GlobalVariable *GVar =
+          const_cast<GlobalVariable *>(dyn_cast<GlobalVariable>(GV)))
+    EmitGlobalVariable(GVar);
+  else
+    llvm_unreachable("Global hasn't had an address allocated yet!");
+
+  return getPointerToGlobalIfAvailable(GV);
+}
+
+/// Converts a Constant* into a GenericValue, including handling of
+/// ConstantExpr values.
+GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
+  // If its undefined, return the garbage.
+  if (isa<UndefValue>(C)) {
+    GenericValue Result;
+    switch (C->getType()->getTypeID()) {
+    default:
+      break;
+    case Type::IntegerTyID:
+    case Type::X86_FP80TyID:
+    case Type::FP128TyID:
+    case Type::PPC_FP128TyID:
+      // Although the value is undefined, we still have to construct an APInt
+      // with the correct bit width.
+      Result.IntVal = APInt(C->getType()->getPrimitiveSizeInBits(), 0);
+      break;
+    case Type::StructTyID: {
+      // if the whole struct is 'undef' just reserve memory for the value.
+      if(StructType *STy = dyn_cast<StructType>(C->getType())) {
+        unsigned int elemNum = STy->getNumElements();
+        Result.AggregateVal.resize(elemNum);
+        for (unsigned int i = 0; i < elemNum; ++i) {
+          Type *ElemTy = STy->getElementType(i);
+          if (ElemTy->isIntegerTy())
+            Result.AggregateVal[i].IntVal =
+              APInt(ElemTy->getPrimitiveSizeInBits(), 0);
+          else if (ElemTy->isAggregateType()) {
+              const Constant *ElemUndef = UndefValue::get(ElemTy);
+              Result.AggregateVal[i] = getConstantValue(ElemUndef);
+            }
+          }
+        }
+      }
+      break;
+    case Type::VectorTyID:
+      // if the whole vector is 'undef' just reserve memory for the value.
+      auto* VTy = cast<VectorType>(C->getType());
+      Type *ElemTy = VTy->getElementType();
+      unsigned int elemNum = VTy->getNumElements();
+      Result.AggregateVal.resize(elemNum);
+      if (ElemTy->isIntegerTy())
+        for (unsigned int i = 0; i < elemNum; ++i)
+          Result.AggregateVal[i].IntVal =
+            APInt(ElemTy->getPrimitiveSizeInBits(), 0);
+      break;
+    }
+    return Result;
+  }
+
+  // Otherwise, if the value is a ConstantExpr...
+  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
+    Constant *Op0 = CE->getOperand(0);
+    switch (CE->getOpcode()) {
+    case Instruction::GetElementPtr: {
+      // Compute the index
+      GenericValue Result = getConstantValue(Op0);
+      APInt Offset(DL.getPointerSizeInBits(), 0);
+      cast<GEPOperator>(CE)->accumulateConstantOffset(DL, Offset);
+
+      char* tmp = (char*) Result.PointerVal;
+      Result = PTOGV(tmp + Offset.getSExtValue());
+      return Result;
+    }
+    case Instruction::Trunc: {
+      GenericValue GV = getConstantValue(Op0);
+      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
+      GV.IntVal = GV.IntVal.trunc(BitWidth);
+      return GV;
+    }
+    case Instruction::ZExt: {
+      GenericValue GV = getConstantValue(Op0);
+      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
+      GV.IntVal = GV.IntVal.zext(BitWidth);
+      return GV;
+    }
+    case Instruction::SExt: {
+      GenericValue GV = getConstantValue(Op0);
+      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
+      GV.IntVal = GV.IntVal.sext(BitWidth);
+      return GV;
+    }
+    case Instruction::FPTrunc: {
+      // FIXME long double
+      GenericValue GV = getConstantValue(Op0);
+      GV.FloatVal = float(GV.DoubleVal);
+      return GV;
+    }
+    case Instruction::FPExt:{
+      // FIXME long double
+      GenericValue GV = getConstantValue(Op0);
+      GV.DoubleVal = double(GV.FloatVal);
+      return GV;
+    }
+    case Instruction::UIToFP: {
+      GenericValue GV = getConstantValue(Op0);
+      if (CE->getType()->isFloatTy())
+        GV.FloatVal = float(GV.IntVal.roundToDouble());
+      else if (CE->getType()->isDoubleTy())
+        GV.DoubleVal = GV.IntVal.roundToDouble();
+      else if (CE->getType()->isX86_FP80Ty()) {
+        APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended());
+        (void)apf.convertFromAPInt(GV.IntVal,
+                                   false,
+                                   APFloat::rmNearestTiesToEven);
+        GV.IntVal = apf.bitcastToAPInt();
+      }
+      return GV;
+    }
+    case Instruction::SIToFP: {
+      GenericValue GV = getConstantValue(Op0);
+      if (CE->getType()->isFloatTy())
+        GV.FloatVal = float(GV.IntVal.signedRoundToDouble());
+      else if (CE->getType()->isDoubleTy())
+        GV.DoubleVal = GV.IntVal.signedRoundToDouble();
+      else if (CE->getType()->isX86_FP80Ty()) {
+        APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended());
+        (void)apf.convertFromAPInt(GV.IntVal,
+                                   true,
+                                   APFloat::rmNearestTiesToEven);
+        GV.IntVal = apf.bitcastToAPInt();
+      }
+      return GV;
+    }
+    case Instruction::FPToUI: // double->APInt conversion handles sign
+    case Instruction::FPToSI: {
+      GenericValue GV = getConstantValue(Op0);
+      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
+      if (Op0->getType()->isFloatTy())
+        GV.IntVal = APIntOps::RoundFloatToAPInt(GV.FloatVal, BitWidth);
+      else if (Op0->getType()->isDoubleTy())
+        GV.IntVal = APIntOps::RoundDoubleToAPInt(GV.DoubleVal, BitWidth);
+      else if (Op0->getType()->isX86_FP80Ty()) {
+        APFloat apf = APFloat(APFloat::x87DoubleExtended(), GV.IntVal);
+        uint64_t v;
+        bool ignored;
+        (void)apf.convertToInteger(makeMutableArrayRef(v), BitWidth,
+                                   CE->getOpcode()==Instruction::FPToSI,
+                                   APFloat::rmTowardZero, &ignored);
+        GV.IntVal = v; // endian?
+      }
+      return GV;
+    }
+    case Instruction::PtrToInt: {
+      GenericValue GV = getConstantValue(Op0);
+      uint32_t PtrWidth = DL.getTypeSizeInBits(Op0->getType());
+      assert(PtrWidth <= 64 && "Bad pointer width");
+      GV.IntVal = APInt(PtrWidth, uintptr_t(GV.PointerVal));
+      uint32_t IntWidth = DL.getTypeSizeInBits(CE->getType());
+      GV.IntVal = GV.IntVal.zextOrTrunc(IntWidth);
+      return GV;
+    }
+    case Instruction::IntToPtr: {
+      GenericValue GV = getConstantValue(Op0);
+      uint32_t PtrWidth = DL.getTypeSizeInBits(CE->getType());
+      GV.IntVal = GV.IntVal.zextOrTrunc(PtrWidth);
+      assert(GV.IntVal.getBitWidth() <= 64 && "Bad pointer width");
+      GV.PointerVal = PointerTy(uintptr_t(GV.IntVal.getZExtValue()));
+      return GV;
+    }
+    case Instruction::BitCast: {
+      GenericValue GV = getConstantValue(Op0);
+      Type* DestTy = CE->getType();
+      switch (Op0->getType()->getTypeID()) {
+        default: llvm_unreachable("Invalid bitcast operand");
+        case Type::IntegerTyID:
+          assert(DestTy->isFloatingPointTy() && "invalid bitcast");
+          if (DestTy->isFloatTy())
+            GV.FloatVal = GV.IntVal.bitsToFloat();
+          else if (DestTy->isDoubleTy())
+            GV.DoubleVal = GV.IntVal.bitsToDouble();
+          break;
+        case Type::FloatTyID:
+          assert(DestTy->isIntegerTy(32) && "Invalid bitcast");
+          GV.IntVal = APInt::floatToBits(GV.FloatVal);
+          break;
+        case Type::DoubleTyID:
+          assert(DestTy->isIntegerTy(64) && "Invalid bitcast");
+          GV.IntVal = APInt::doubleToBits(GV.DoubleVal);
+          break;
+        case Type::PointerTyID:
+          assert(DestTy->isPointerTy() && "Invalid bitcast");
+          break; // getConstantValue(Op0)  above already converted it
+      }
+      return GV;
+    }
+    case Instruction::Add:
+    case Instruction::FAdd:
+    case Instruction::Sub:
+    case Instruction::FSub:
+    case Instruction::Mul:
+    case Instruction::FMul:
+    case Instruction::UDiv:
+    case Instruction::SDiv:
+    case Instruction::URem:
+    case Instruction::SRem:
+    case Instruction::And:
+    case Instruction::Or:
+    case Instruction::Xor: {
+      GenericValue LHS = getConstantValue(Op0);
+      GenericValue RHS = getConstantValue(CE->getOperand(1));
+      GenericValue GV;
+      switch (CE->getOperand(0)->getType()->getTypeID()) {
+      default: llvm_unreachable("Bad add type!");
+      case Type::IntegerTyID:
+        switch (CE->getOpcode()) {
+          default: llvm_unreachable("Invalid integer opcode");
+          case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
+          case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
+          case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
+          case Instruction::UDiv:GV.IntVal = LHS.IntVal.udiv(RHS.IntVal); break;
+          case Instruction::SDiv:GV.IntVal = LHS.IntVal.sdiv(RHS.IntVal); break;
+          case Instruction::URem:GV.IntVal = LHS.IntVal.urem(RHS.IntVal); break;
+          case Instruction::SRem:GV.IntVal = LHS.IntVal.srem(RHS.IntVal); break;
+          case Instruction::And: GV.IntVal = LHS.IntVal & RHS.IntVal; break;
+          case Instruction::Or:  GV.IntVal = LHS.IntVal | RHS.IntVal; break;
+          case Instruction::Xor: GV.IntVal = LHS.IntVal ^ RHS.IntVal; break;
+        }
+        break;
+      case Type::FloatTyID:
+        switch (CE->getOpcode()) {
+          default: llvm_unreachable("Invalid float opcode");
+          case Instruction::FAdd:
+            GV.FloatVal = LHS.FloatVal + RHS.FloatVal; break;
+          case Instruction::FSub:
+            GV.FloatVal = LHS.FloatVal - RHS.FloatVal; break;
+          case Instruction::FMul:
+            GV.FloatVal = LHS.FloatVal * RHS.FloatVal; break;
+          case Instruction::FDiv:
+            GV.FloatVal = LHS.FloatVal / RHS.FloatVal; break;
+          case Instruction::FRem:
+            GV.FloatVal = std::fmod(LHS.FloatVal,RHS.FloatVal); break;
+        }
+        break;
+      case Type::DoubleTyID:
+        switch (CE->getOpcode()) {
+          default: llvm_unreachable("Invalid double opcode");
+          case Instruction::FAdd:
+            GV.DoubleVal = LHS.DoubleVal + RHS.DoubleVal; break;
+          case Instruction::FSub:
+            GV.DoubleVal = LHS.DoubleVal - RHS.DoubleVal; break;
+          case Instruction::FMul:
+            GV.DoubleVal = LHS.DoubleVal * RHS.DoubleVal; break;
+          case Instruction::FDiv:
+            GV.DoubleVal = LHS.DoubleVal / RHS.DoubleVal; break;
+          case Instruction::FRem:
+            GV.DoubleVal = std::fmod(LHS.DoubleVal,RHS.DoubleVal); break;
+        }
+        break;
+      case Type::X86_FP80TyID:
+      case Type::PPC_FP128TyID:
+      case Type::FP128TyID: {
+        const fltSemantics &Sem = CE->getOperand(0)->getType()->getFltSemantics();
+        APFloat apfLHS = APFloat(Sem, LHS.IntVal);
+        switch (CE->getOpcode()) {
+          default: llvm_unreachable("Invalid long double opcode");
+          case Instruction::FAdd:
+            apfLHS.add(APFloat(Sem, RHS.IntVal), APFloat::rmNearestTiesToEven);
+            GV.IntVal = apfLHS.bitcastToAPInt();
+            break;
+          case Instruction::FSub:
+            apfLHS.subtract(APFloat(Sem, RHS.IntVal),
+                            APFloat::rmNearestTiesToEven);
+            GV.IntVal = apfLHS.bitcastToAPInt();
+            break;
+          case Instruction::FMul:
+            apfLHS.multiply(APFloat(Sem, RHS.IntVal),
+                            APFloat::rmNearestTiesToEven);
+            GV.IntVal = apfLHS.bitcastToAPInt();
+            break;
+          case Instruction::FDiv:
+            apfLHS.divide(APFloat(Sem, RHS.IntVal),
+                          APFloat::rmNearestTiesToEven);
+            GV.IntVal = apfLHS.bitcastToAPInt();
+            break;
+          case Instruction::FRem:
+            apfLHS.mod(APFloat(Sem, RHS.IntVal));
+            GV.IntVal = apfLHS.bitcastToAPInt();
+            break;
+          }
+        }
+        break;
+      }
+      return GV;
+    }
+    default:
+      break;
+    }
+
+    SmallString<256> Msg;
+    raw_svector_ostream OS(Msg);
+    OS << "ConstantExpr not handled: " << *CE;
+    report_fatal_error(OS.str());
+  }
+
+  // Otherwise, we have a simple constant.
+  GenericValue Result;
+  switch (C->getType()->getTypeID()) {
+  case Type::FloatTyID:
+    Result.FloatVal = cast<ConstantFP>(C)->getValueAPF().convertToFloat();
+    break;
+  case Type::DoubleTyID:
+    Result.DoubleVal = cast<ConstantFP>(C)->getValueAPF().convertToDouble();
+    break;
+  case Type::X86_FP80TyID:
+  case Type::FP128TyID:
+  case Type::PPC_FP128TyID:
+    Result.IntVal = cast <ConstantFP>(C)->getValueAPF().bitcastToAPInt();
+    break;
+  case Type::IntegerTyID:
+    Result.IntVal = cast<ConstantInt>(C)->getValue();
+    break;
+  case Type::PointerTyID:
+    while (auto *A = dyn_cast<GlobalAlias>(C)) {
+      C = A->getAliasee();
+    }
+    if (isa<ConstantPointerNull>(C))
+      Result.PointerVal = nullptr;
+    else if (const Function *F = dyn_cast<Function>(C))
+      Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
+    else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
+      Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
+    else
+      llvm_unreachable("Unknown constant pointer type!");
+    break;
+  case Type::VectorTyID: {
+    unsigned elemNum;
+    Type* ElemTy;
+    const ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(C);
+    const ConstantVector *CV = dyn_cast<ConstantVector>(C);
+    const ConstantAggregateZero *CAZ = dyn_cast<ConstantAggregateZero>(C);
+
+    if (CDV) {
+        elemNum = CDV->getNumElements();
+        ElemTy = CDV->getElementType();
+    } else if (CV || CAZ) {
+        auto* VTy = cast<VectorType>(C->getType());
+        elemNum = VTy->getNumElements();
+        ElemTy = VTy->getElementType();
+    } else {
+        llvm_unreachable("Unknown constant vector type!");
+    }
+
+    Result.AggregateVal.resize(elemNum);
+    // Check if vector holds floats.
+    if(ElemTy->isFloatTy()) {
+      if (CAZ) {
+        GenericValue floatZero;
+        floatZero.FloatVal = 0.f;
+        std::fill(Result.AggregateVal.begin(), Result.AggregateVal.end(),
+                  floatZero);
+        break;
+      }
+      if(CV) {
+        for (unsigned i = 0; i < elemNum; ++i)
+          if (!isa<UndefValue>(CV->getOperand(i)))
+            Result.AggregateVal[i].FloatVal = cast<ConstantFP>(
+              CV->getOperand(i))->getValueAPF().convertToFloat();
+        break;
+      }
+      if(CDV)
+        for (unsigned i = 0; i < elemNum; ++i)
+          Result.AggregateVal[i].FloatVal = CDV->getElementAsFloat(i);
+
+      break;
+    }
+    // Check if vector holds doubles.
+    if (ElemTy->isDoubleTy()) {
+      if (CAZ) {
+        GenericValue doubleZero;
+        doubleZero.DoubleVal = 0.0;
+        std::fill(Result.AggregateVal.begin(), Result.AggregateVal.end(),
+                  doubleZero);
+        break;
+      }
+      if(CV) {
+        for (unsigned i = 0; i < elemNum; ++i)
+          if (!isa<UndefValue>(CV->getOperand(i)))
+            Result.AggregateVal[i].DoubleVal = cast<ConstantFP>(
+              CV->getOperand(i))->getValueAPF().convertToDouble();
+        break;
+      }
+      if(CDV)
+        for (unsigned i = 0; i < elemNum; ++i)
+          Result.AggregateVal[i].DoubleVal = CDV->getElementAsDouble(i);
+
+      break;
+    }
+    // Check if vector holds integers.
+    if (ElemTy->isIntegerTy()) {
+      if (CAZ) {
+        GenericValue intZero;
+        intZero.IntVal = APInt(ElemTy->getScalarSizeInBits(), 0ull);
+        std::fill(Result.AggregateVal.begin(), Result.AggregateVal.end(),
+                  intZero);
+        break;
+      }
+      if(CV) {
+        for (unsigned i = 0; i < elemNum; ++i)
+          if (!isa<UndefValue>(CV->getOperand(i)))
+            Result.AggregateVal[i].IntVal = cast<ConstantInt>(
+                                            CV->getOperand(i))->getValue();
+          else {
+            Result.AggregateVal[i].IntVal =
+              APInt(CV->getOperand(i)->getType()->getPrimitiveSizeInBits(), 0);
+          }
+        break;
+      }
+      if(CDV)
+        for (unsigned i = 0; i < elemNum; ++i)
+          Result.AggregateVal[i].IntVal = APInt(
+            CDV->getElementType()->getPrimitiveSizeInBits(),
+            CDV->getElementAsInteger(i));
+
+      break;
+    }
+    llvm_unreachable("Unknown constant pointer type!");
+  }
+  break;
+
+  default:
+    SmallString<256> Msg;
+    raw_svector_ostream OS(Msg);
+    OS << "ERROR: Constant unimplemented for type: " << *C->getType();
+    report_fatal_error(OS.str());
+  }
+
+  return Result;
+}
+
+void ExecutionEngine::StoreValueToMemory(const GenericValue &Val,
+                                         GenericValue *Ptr, Type *Ty) {
+  const unsigned StoreBytes = getDataLayout().getTypeStoreSize(Ty);
+
+  switch (Ty->getTypeID()) {
+  default:
+    dbgs() << "Cannot store value of type " << *Ty << "!\n";
+    break;
+  case Type::IntegerTyID:
+    StoreIntToMemory(Val.IntVal, (uint8_t*)Ptr, StoreBytes);
+    break;
+  case Type::FloatTyID:
+    *((float*)Ptr) = Val.FloatVal;
+    break;
+  case Type::DoubleTyID:
+    *((double*)Ptr) = Val.DoubleVal;
+    break;
+  case Type::X86_FP80TyID:
+    memcpy(Ptr, Val.IntVal.getRawData(), 10);
+    break;
+  case Type::PointerTyID:
+    // Ensure 64 bit target pointers are fully initialized on 32 bit hosts.
+    if (StoreBytes != sizeof(PointerTy))
+      memset(&(Ptr->PointerVal), 0, StoreBytes);
+
+    *((PointerTy*)Ptr) = Val.PointerVal;
+    break;
+  case Type::VectorTyID:
+    for (unsigned i = 0; i < Val.AggregateVal.size(); ++i) {
+      if (cast<VectorType>(Ty)->getElementType()->isDoubleTy())
+        *(((double*)Ptr)+i) = Val.AggregateVal[i].DoubleVal;
+      if (cast<VectorType>(Ty)->getElementType()->isFloatTy())
+        *(((float*)Ptr)+i) = Val.AggregateVal[i].FloatVal;
+      if (cast<VectorType>(Ty)->getElementType()->isIntegerTy()) {
+        unsigned numOfBytes =(Val.AggregateVal[i].IntVal.getBitWidth()+7)/8;
+        StoreIntToMemory(Val.AggregateVal[i].IntVal,
+          (uint8_t*)Ptr + numOfBytes*i, numOfBytes);
+      }
+    }
+    break;
+  }
+
+  if (sys::IsLittleEndianHost != getDataLayout().isLittleEndian())
+    // Host and target are different endian - reverse the stored bytes.
+    std::reverse((uint8_t*)Ptr, StoreBytes + (uint8_t*)Ptr);
+}
+
+/// FIXME: document
+///
+void ExecutionEngine::LoadValueFromMemory(GenericValue &Result,
+                                          GenericValue *Ptr,
+                                          Type *Ty) {
+  const unsigned LoadBytes = getDataLayout().getTypeStoreSize(Ty);
+
+  switch (Ty->getTypeID()) {
+  case Type::IntegerTyID:
+    // An APInt with all words initially zero.
+    Result.IntVal = APInt(cast<IntegerType>(Ty)->getBitWidth(), 0);
+    LoadIntFromMemory(Result.IntVal, (uint8_t*)Ptr, LoadBytes);
+    break;
+  case Type::FloatTyID:
+    Result.FloatVal = *((float*)Ptr);
+    break;
+  case Type::DoubleTyID:
+    Result.DoubleVal = *((double*)Ptr);
+    break;
+  case Type::PointerTyID:
+    Result.PointerVal = *((PointerTy*)Ptr);
+    break;
+  case Type::X86_FP80TyID: {
+    // This is endian dependent, but it will only work on x86 anyway.
+    // FIXME: Will not trap if loading a signaling NaN.
+    uint64_t y[2];
+    memcpy(y, Ptr, 10);
+    Result.IntVal = APInt(80, y);
+    break;
+  }
+  case Type::VectorTyID: {
+    auto *VT = cast<VectorType>(Ty);
+    Type *ElemT = VT->getElementType();
+    const unsigned numElems = VT->getNumElements();
+    if (ElemT->isFloatTy()) {
+      Result.AggregateVal.resize(numElems);
+      for (unsigned i = 0; i < numElems; ++i)
+        Result.AggregateVal[i].FloatVal = *((float*)Ptr+i);
+    }
+    if (ElemT->isDoubleTy()) {
+      Result.AggregateVal.resize(numElems);
+      for (unsigned i = 0; i < numElems; ++i)
+        Result.AggregateVal[i].DoubleVal = *((double*)Ptr+i);
+    }
+    if (ElemT->isIntegerTy()) {
+      GenericValue intZero;
+      const unsigned elemBitWidth = cast<IntegerType>(ElemT)->getBitWidth();
+      intZero.IntVal = APInt(elemBitWidth, 0);
+      Result.AggregateVal.resize(numElems, intZero);
+      for (unsigned i = 0; i < numElems; ++i)
+        LoadIntFromMemory(Result.AggregateVal[i].IntVal,
+          (uint8_t*)Ptr+((elemBitWidth+7)/8)*i, (elemBitWidth+7)/8);
+    }
+  break;
+  }
+  default:
+    SmallString<256> Msg;
+    raw_svector_ostream OS(Msg);
+    OS << "Cannot load value of type " << *Ty << "!";
+    report_fatal_error(OS.str());
+  }
+}
+
+void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
+  LLVM_DEBUG(dbgs() << "JIT: Initializing " << Addr << " ");
+  LLVM_DEBUG(Init->dump());
+  if (isa<UndefValue>(Init))
+    return;
+
+  if (const ConstantVector *CP = dyn_cast<ConstantVector>(Init)) {
+    unsigned ElementSize =
+        getDataLayout().getTypeAllocSize(CP->getType()->getElementType());
+    for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
+      InitializeMemory(CP->getOperand(i), (char*)Addr+i*ElementSize);
+    return;
+  }
+
+  if (isa<ConstantAggregateZero>(Init)) {
+    memset(Addr, 0, (size_t)getDataLayout().getTypeAllocSize(Init->getType()));
+    return;
+  }
+
+  if (const ConstantArray *CPA = dyn_cast<ConstantArray>(Init)) {
+    unsigned ElementSize =
+        getDataLayout().getTypeAllocSize(CPA->getType()->getElementType());
+    for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
+      InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
+    return;
+  }
+
+  if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(Init)) {
+    const StructLayout *SL =
+        getDataLayout().getStructLayout(cast<StructType>(CPS->getType()));
+    for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
+      InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->getElementOffset(i));
+    return;
+  }
+
+  if (const ConstantDataSequential *CDS =
+               dyn_cast<ConstantDataSequential>(Init)) {
+    // CDS is already laid out in host memory order.
+    StringRef Data = CDS->getRawDataValues();
+    memcpy(Addr, Data.data(), Data.size());
+    return;
+  }
+
+  if (Init->getType()->isFirstClassType()) {
+    GenericValue Val = getConstantValue(Init);
+    StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
+    return;
+  }
+
+  LLVM_DEBUG(dbgs() << "Bad Type: " << *Init->getType() << "\n");
+  llvm_unreachable("Unknown constant type to initialize memory with!");
+}
+
+/// EmitGlobals - Emit all of the global variables to memory, storing their
+/// addresses into GlobalAddress.  This must make sure to copy the contents of
+/// their initializers into the memory.
+void ExecutionEngine::emitGlobals() {
+  // Loop over all of the global variables in the program, allocating the memory
+  // to hold them.  If there is more than one module, do a prepass over globals
+  // to figure out how the different modules should link together.
+  std::map<std::pair<std::string, Type*>,
+           const GlobalValue*> LinkedGlobalsMap;
+
+  if (Modules.size() != 1) {
+    for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
+      Module &M = *Modules[m];
+      for (const auto &GV : M.globals()) {
+        if (GV.hasLocalLinkage() || GV.isDeclaration() ||
+            GV.hasAppendingLinkage() || !GV.hasName())
+          continue;// Ignore external globals and globals with internal linkage.
+
+        const GlobalValue *&GVEntry = LinkedGlobalsMap[std::make_pair(
+            std::string(GV.getName()), GV.getType())];
+
+        // If this is the first time we've seen this global, it is the canonical
+        // version.
+        if (!GVEntry) {
+          GVEntry = &GV;
+          continue;
+        }
+
+        // If the existing global is strong, never replace it.
+        if (GVEntry->hasExternalLinkage())
+          continue;
+
+        // Otherwise, we know it's linkonce/weak, replace it if this is a strong
+        // symbol.  FIXME is this right for common?
+        if (GV.hasExternalLinkage() || GVEntry->hasExternalWeakLinkage())
+          GVEntry = &GV;
+      }
+    }
+  }
+
+  std::vector<const GlobalValue*> NonCanonicalGlobals;
+  for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
+    Module &M = *Modules[m];
+    for (const auto &GV : M.globals()) {
+      // In the multi-module case, see what this global maps to.
+      if (!LinkedGlobalsMap.empty()) {
+        if (const GlobalValue *GVEntry = LinkedGlobalsMap[std::make_pair(
+                std::string(GV.getName()), GV.getType())]) {
+          // If something else is the canonical global, ignore this one.
+          if (GVEntry != &GV) {
+            NonCanonicalGlobals.push_back(&GV);
+            continue;
+          }
+        }
+      }
+
+      if (!GV.isDeclaration()) {
+        addGlobalMapping(&GV, getMemoryForGV(&GV));
+      } else {
+        // External variable reference. Try to use the dynamic loader to
+        // get a pointer to it.
+        if (void *SymAddr = sys::DynamicLibrary::SearchForAddressOfSymbol(
+                std::string(GV.getName())))
+          addGlobalMapping(&GV, SymAddr);
+        else {
+          report_fatal_error("Could not resolve external global address: "
+                            +GV.getName());
+        }
+      }
+    }
+
+    // If there are multiple modules, map the non-canonical globals to their
+    // canonical location.
+    if (!NonCanonicalGlobals.empty()) {
+      for (unsigned i = 0, e = NonCanonicalGlobals.size(); i != e; ++i) {
+        const GlobalValue *GV = NonCanonicalGlobals[i];
+        const GlobalValue *CGV = LinkedGlobalsMap[std::make_pair(
+            std::string(GV->getName()), GV->getType())];
+        void *Ptr = getPointerToGlobalIfAvailable(CGV);
+        assert(Ptr && "Canonical global wasn't codegen'd!");
+        addGlobalMapping(GV, Ptr);
+      }
+    }
+
+    // Now that all of the globals are set up in memory, loop through them all
+    // and initialize their contents.
+    for (const auto &GV : M.globals()) {
+      if (!GV.isDeclaration()) {
+        if (!LinkedGlobalsMap.empty()) {
+          if (const GlobalValue *GVEntry = LinkedGlobalsMap[std::make_pair(
+                  std::string(GV.getName()), GV.getType())])
+            if (GVEntry != &GV)  // Not the canonical variable.
+              continue;
+        }
+        EmitGlobalVariable(&GV);
+      }
+    }
+  }
+}
+
+// EmitGlobalVariable - This method emits the specified global variable to the
+// address specified in GlobalAddresses, or allocates new memory if it's not
+// already in the map.
+void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
+  void *GA = getPointerToGlobalIfAvailable(GV);
+
+  if (!GA) {
+    // If it's not already specified, allocate memory for the global.
+    GA = getMemoryForGV(GV);
+
+    // If we failed to allocate memory for this global, return.
+    if (!GA) return;
+
+    addGlobalMapping(GV, GA);
+  }
+
+  // Don't initialize if it's thread local, let the client do it.
+  if (!GV->isThreadLocal())
+    InitializeMemory(GV->getInitializer(), GA);
+
+  Type *ElTy = GV->getValueType();
+  size_t GVSize = (size_t)getDataLayout().getTypeAllocSize(ElTy);
+  NumInitBytes += (unsigned)GVSize;
+  ++NumGlobals;
+}