Temporarily Revert "Nuke the old JIT." as it's not quite ready to

be deleted. This will be reapplied as soon as possible and before
the 3.6 branch date at any rate.

Approved by Jim Grosbach, Lang Hames, Rafael Espindola.

This reverts commits r215111, 215115, 215116, 215117, 215136.

llvm-svn: 215154

17 files changed, 2295 insertions, 12 deletions

diff --git a/llvm/lib/ExecutionEngine/CMakeLists.txt b/llvm/lib/ExecutionEngine/CMakeLists.txt
index 208495c8847..3102c7bd582 100644
--- a/llvm/lib/ExecutionEngine/CMakeLists.txt
+++ b/llvm/lib/ExecutionEngine/CMakeLists.txt
@@ -8,6 +8,7 @@ add_llvm_library(LLVMExecutionEngine
   )
 
 add_subdirectory(Interpreter)
+add_subdirectory(JIT)
 add_subdirectory(MCJIT)
 add_subdirectory(RuntimeDyld)
 
diff --git a/llvm/lib/ExecutionEngine/ExecutionEngine.cpp b/llvm/lib/ExecutionEngine/ExecutionEngine.cpp
index 01b9bcc8905..063f3fb05c2 100644
--- a/llvm/lib/ExecutionEngine/ExecutionEngine.cpp
+++ b/llvm/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -48,6 +48,12 @@ void ObjectCache::anchor() {}
 void ObjectBuffer::anchor() {}
 void ObjectBufferStream::anchor() {}
 
+ExecutionEngine *(*ExecutionEngine::JITCtor)(
+  Module *M,
+  std::string *ErrorStr,
+  JITMemoryManager *JMM,
+  bool GVsWithCode,
+  TargetMachine *TM) = nullptr;
 ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
   Module *M,
   std::string *ErrorStr,
@@ -411,8 +417,10 @@ void EngineBuilder::InitEngine() {
   MCJMM = nullptr;
   JMM = nullptr;
   Options = TargetOptions();
+  AllocateGVsWithCode = false;
   RelocModel = Reloc::Default;
   CMModel = CodeModel::JITDefault;
+  UseMCJIT = false;
 
 // IR module verification is enabled by default in debug builds, and disabled
 // by default in release builds.
@@ -445,6 +453,14 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
       return nullptr;
     }
   }
+  
+  if (MCJMM && ! UseMCJIT) {
+    if (ErrorStr)
+      *ErrorStr =
+        "Cannot create a legacy JIT with a runtime dyld memory "
+        "manager.";
+    return nullptr;
+  }
 
   // Unless the interpreter was explicitly selected or the JIT is not linked,
   // try making a JIT.
@@ -457,9 +473,12 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
     }
 
     ExecutionEngine *EE = nullptr;
-    if (ExecutionEngine::MCJITCtor)
+    if (UseMCJIT && ExecutionEngine::MCJITCtor)
       EE = ExecutionEngine::MCJITCtor(M, ErrorStr, MCJMM ? MCJMM : JMM,
                                       TheTM.release());
+    else if (ExecutionEngine::JITCtor)
+      EE = ExecutionEngine::JITCtor(M, ErrorStr, JMM,
+                                    AllocateGVsWithCode, TheTM.release());
 
     if (EE) {
       EE->setVerifyModules(VerifyModules);
@@ -477,7 +496,8 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
     return nullptr;
   }
 
-  if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::MCJITCtor) {
+  if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::JITCtor &&
+      !ExecutionEngine::MCJITCtor) {
     if (ErrorStr)
       *ErrorStr = "JIT has not been linked in.";
   }
@@ -823,6 +843,9 @@ GenericValue ExecutionEngine::getConstantValue(const Constant *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 if (const BlockAddress *BA = dyn_cast<BlockAddress>(C))
+      Result = PTOGV(getPointerToBasicBlock(const_cast<BasicBlock*>(
+                                                        BA->getBasicBlock())));
     else
       llvm_unreachable("Unknown constant pointer type!");
     break;
diff --git a/llvm/lib/ExecutionEngine/ExecutionEngineBindings.cpp b/llvm/lib/ExecutionEngine/ExecutionEngineBindings.cpp
index fa2f23809a8..6ff1e7ac063 100644
--- a/llvm/lib/ExecutionEngine/ExecutionEngineBindings.cpp
+++ b/llvm/lib/ExecutionEngine/ExecutionEngineBindings.cpp
@@ -192,6 +192,7 @@ LLVMBool LLVMCreateMCJITCompilerForModule(
   EngineBuilder builder(unwrap(M));
   builder.setEngineKind(EngineKind::JIT)
          .setErrorStr(&Error)
+         .setUseMCJIT(true)
          .setOptLevel((CodeGenOpt::Level)options.OptLevel)
          .setCodeModel(unwrap(options.CodeModel))
          .setTargetOptions(targetOptions);
@@ -274,6 +275,7 @@ LLVMGenericValueRef LLVMRunFunction(LLVMExecutionEngineRef EE, LLVMValueRef F,
 }
 
 void LLVMFreeMachineCodeForFunction(LLVMExecutionEngineRef EE, LLVMValueRef F) {
+  unwrap(EE)->freeMachineCodeForFunction(unwrap<Function>(F));
 }
 
 void LLVMAddModule(LLVMExecutionEngineRef EE, LLVMModuleRef M){
@@ -312,7 +314,7 @@ LLVMBool LLVMFindFunction(LLVMExecutionEngineRef EE, const char *Name,
 
 void *LLVMRecompileAndRelinkFunction(LLVMExecutionEngineRef EE,
                                      LLVMValueRef Fn) {
-  return nullptr;
+  return unwrap(EE)->recompileAndRelinkFunction(unwrap<Function>(Fn));
 }
 
 LLVMTargetDataRef LLVMGetExecutionEngineTargetData(LLVMExecutionEngineRef EE) {
diff --git a/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h b/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h
index ed6f8f44629..2145cde05fb 100644
--- a/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h
+++ b/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h
@@ -121,6 +121,17 @@ public:
     return nullptr;
   }
 
+  /// recompileAndRelinkFunction - For the interpreter, functions are always
+  /// up-to-date.
+  ///
+  void *recompileAndRelinkFunction(Function *F) override {
+    return getPointerToFunction(F);
+  }
+
+  /// freeMachineCodeForFunction - The interpreter does not generate any code.
+  ///
+  void freeMachineCodeForFunction(Function *F) override { }
+
   // Methods used to execute code:
   // Place a call on the stack
   void callFunction(Function *F, const std::vector<GenericValue> &ArgVals);
@@ -202,6 +213,7 @@ private:  // Helper functions
   void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
 
   void *getPointerToFunction(Function *F) override { return (void*)F; }
+  void *getPointerToBasicBlock(BasicBlock *BB) override { return (void*)BB; }
 
   void initializeExecutionEngine() { }
   void initializeExternalFunctions();
diff --git a/llvm/lib/ExecutionEngine/JIT/CMakeLists.txt b/llvm/lib/ExecutionEngine/JIT/CMakeLists.txt
new file mode 100644
index 00000000000..e16baede50f
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JIT/CMakeLists.txt
@@ -0,0 +1,8 @@
+# TODO: Support other architectures. See Makefile.
+add_definitions(-DENABLE_X86_JIT)
+
+add_llvm_library(LLVMJIT
+  JIT.cpp
+  JITEmitter.cpp
+  JITMemoryManager.cpp
+  )
diff --git a/llvm/lib/ExecutionEngine/JIT/JIT.cpp b/llvm/lib/ExecutionEngine/JIT/JIT.cpp
new file mode 100644
index 00000000000..ab0c1a680bd
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JIT/JIT.cpp
@@ -0,0 +1,696 @@
+//===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This tool implements a just-in-time compiler for LLVM, allowing direct
+// execution of LLVM bitcode in an efficient manner.
+//
+//===----------------------------------------------------------------------===//
+
+#include "JIT.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/CodeGen/JITCodeEmitter.h"
+#include "llvm/CodeGen/MachineCodeInfo.h"
+#include "llvm/Config/config.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ExecutionEngine/JITEventListener.h"
+#include "llvm/ExecutionEngine/JITMemoryManager.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MutexGuard.h"
+#include "llvm/Target/TargetJITInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+
+using namespace llvm;
+
+#ifdef __APPLE__
+// Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
+// of atexit). It passes the address of linker generated symbol __dso_handle
+// to the function.
+// This configuration change happened at version 5330.
+# include <AvailabilityMacros.h>
+# if defined(MAC_OS_X_VERSION_10_4) && \
+     ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
+      (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
+       __APPLE_CC__ >= 5330))
+#  ifndef HAVE___DSO_HANDLE
+#   define HAVE___DSO_HANDLE 1
+#  endif
+# endif
+#endif
+
+#if HAVE___DSO_HANDLE
+extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
+#endif
+
+namespace {
+
+static struct RegisterJIT {
+  RegisterJIT() { JIT::Register(); }
+} JITRegistrator;
+
+}
+
+extern "C" void LLVMLinkInJIT() {
+}
+
+/// createJIT - This is the factory method for creating a JIT for the current
+/// machine, it does not fall back to the interpreter.  This takes ownership
+/// of the module.
+ExecutionEngine *JIT::createJIT(Module *M,
+                                std::string *ErrorStr,
+                                JITMemoryManager *JMM,
+                                bool GVsWithCode,
+                                TargetMachine *TM) {
+  // Try to register the program as a source of symbols to resolve against.
+  //
+  // FIXME: Don't do this here.
+  sys::DynamicLibrary::LoadLibraryPermanently(nullptr, nullptr);
+
+  // If the target supports JIT code generation, create the JIT.
+  if (TargetJITInfo *TJ = TM->getSubtargetImpl()->getJITInfo()) {
+    return new JIT(M, *TM, *TJ, JMM, GVsWithCode);
+  } else {
+    if (ErrorStr)
+      *ErrorStr = "target does not support JIT code generation";
+    return nullptr;
+  }
+}
+
+namespace {
+/// This class supports the global getPointerToNamedFunction(), which allows
+/// bugpoint or gdb users to search for a function by name without any context.
+class JitPool {
+  SmallPtrSet<JIT*, 1> JITs;  // Optimize for process containing just 1 JIT.
+  mutable sys::Mutex Lock;
+public:
+  void Add(JIT *jit) {
+    MutexGuard guard(Lock);
+    JITs.insert(jit);
+  }
+  void Remove(JIT *jit) {
+    MutexGuard guard(Lock);
+    JITs.erase(jit);
+  }
+  void *getPointerToNamedFunction(const char *Name) const {
+    MutexGuard guard(Lock);
+    assert(JITs.size() != 0 && "No Jit registered");
+    //search function in every instance of JIT
+    for (SmallPtrSet<JIT*, 1>::const_iterator Jit = JITs.begin(),
+           end = JITs.end();
+         Jit != end; ++Jit) {
+      if (Function *F = (*Jit)->FindFunctionNamed(Name))
+        return (*Jit)->getPointerToFunction(F);
+    }
+    // The function is not available : fallback on the first created (will
+    // search in symbol of the current program/library)
+    return (*JITs.begin())->getPointerToNamedFunction(Name);
+  }
+};
+ManagedStatic<JitPool> AllJits;
+}
+extern "C" {
+  // getPointerToNamedFunction - This function is used as a global wrapper to
+  // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
+  // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
+  // need to resolve function(s) that are being mis-codegenerated, so we need to
+  // resolve their addresses at runtime, and this is the way to do it.
+  void *getPointerToNamedFunction(const char *Name) {
+    return AllJits->getPointerToNamedFunction(Name);
+  }
+}
+
+JIT::JIT(Module *M, TargetMachine &tm, TargetJITInfo &tji,
+         JITMemoryManager *jmm, bool GVsWithCode)
+  : ExecutionEngine(M), TM(tm), TJI(tji),
+    JMM(jmm ? jmm : JITMemoryManager::CreateDefaultMemManager()),
+    AllocateGVsWithCode(GVsWithCode), isAlreadyCodeGenerating(false) {
+  setDataLayout(TM.getSubtargetImpl()->getDataLayout());
+
+  jitstate = new JITState(M);
+
+  // Initialize JCE
+  JCE = createEmitter(*this, JMM, TM);
+
+  // Register in global list of all JITs.
+  AllJits->Add(this);
+
+  // Add target data
+  MutexGuard locked(lock);
+  FunctionPassManager &PM = jitstate->getPM();
+  M->setDataLayout(TM.getSubtargetImpl()->getDataLayout());
+  PM.add(new DataLayoutPass(M));
+
+  // Turn the machine code intermediate representation into bytes in memory that
+  // may be executed.
+  if (TM.addPassesToEmitMachineCode(PM, *JCE, !getVerifyModules())) {
+    report_fatal_error("Target does not support machine code emission!");
+  }
+
+  // Initialize passes.
+  PM.doInitialization();
+}
+
+JIT::~JIT() {
+  // Cleanup.
+  AllJits->Remove(this);
+  delete jitstate;
+  delete JCE;
+  // JMM is a ownership of JCE, so we no need delete JMM here.
+  delete &TM;
+}
+
+/// addModule - Add a new Module to the JIT.  If we previously removed the last
+/// Module, we need re-initialize jitstate with a valid Module.
+void JIT::addModule(Module *M) {
+  MutexGuard locked(lock);
+
+  if (Modules.empty()) {
+    assert(!jitstate && "jitstate should be NULL if Modules vector is empty!");
+
+    jitstate = new JITState(M);
+
+    FunctionPassManager &PM = jitstate->getPM();
+    M->setDataLayout(TM.getSubtargetImpl()->getDataLayout());
+    PM.add(new DataLayoutPass(M));
+
+    // Turn the machine code intermediate representation into bytes in memory
+    // that may be executed.
+    if (TM.addPassesToEmitMachineCode(PM, *JCE, !getVerifyModules())) {
+      report_fatal_error("Target does not support machine code emission!");
+    }
+
+    // Initialize passes.
+    PM.doInitialization();
+  }
+
+  ExecutionEngine::addModule(M);
+}
+
+/// removeModule - If we are removing the last Module, invalidate the jitstate
+/// since the PassManager it contains references a released Module.
+bool JIT::removeModule(Module *M) {
+  bool result = ExecutionEngine::removeModule(M);
+
+  MutexGuard locked(lock);
+
+  if (jitstate && jitstate->getModule() == M) {
+    delete jitstate;
+    jitstate = nullptr;
+  }
+
+  if (!jitstate && !Modules.empty()) {
+    jitstate = new JITState(Modules[0]);
+
+    FunctionPassManager &PM = jitstate->getPM();
+    M->setDataLayout(TM.getSubtargetImpl()->getDataLayout());
+    PM.add(new DataLayoutPass(M));
+
+    // Turn the machine code intermediate representation into bytes in memory
+    // that may be executed.
+    if (TM.addPassesToEmitMachineCode(PM, *JCE, !getVerifyModules())) {
+      report_fatal_error("Target does not support machine code emission!");
+    }
+
+    // Initialize passes.
+    PM.doInitialization();
+  }
+  return result;
+}
+
+/// run - Start execution with the specified function and arguments.
+///
+GenericValue JIT::runFunction(Function *F,
+                              const std::vector<GenericValue> &ArgValues) {
+  assert(F && "Function *F was null at entry to run()");
+
+  void *FPtr = getPointerToFunction(F);
+  assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
+  FunctionType *FTy = F->getFunctionType();
+  Type *RetTy = FTy->getReturnType();
+
+  assert((FTy->getNumParams() == ArgValues.size() ||
+          (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
+         "Wrong number of arguments passed into function!");
+  assert(FTy->getNumParams() == ArgValues.size() &&
+         "This doesn't support passing arguments through varargs (yet)!");
+
+  // Handle some common cases first.  These cases correspond to common `main'
+  // prototypes.
+  if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
+    switch (ArgValues.size()) {
+    case 3:
+      if (FTy->getParamType(0)->isIntegerTy(32) &&
+          FTy->getParamType(1)->isPointerTy() &&
+          FTy->getParamType(2)->isPointerTy()) {
+        int (*PF)(int, char **, const char **) =
+          (int(*)(int, char **, const char **))(intptr_t)FPtr;
+
+        // Call the function.
+        GenericValue rv;
+        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
+                                 (char **)GVTOP(ArgValues[1]),
+                                 (const char **)GVTOP(ArgValues[2])));
+        return rv;
+      }
+      break;
+    case 2:
+      if (FTy->getParamType(0)->isIntegerTy(32) &&
+          FTy->getParamType(1)->isPointerTy()) {
+        int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
+
+        // Call the function.
+        GenericValue rv;
+        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
+                                 (char **)GVTOP(ArgValues[1])));
+        return rv;
+      }
+      break;
+    case 1:
+      if (FTy->getParamType(0)->isIntegerTy(32)) {
+        GenericValue rv;
+        int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
+        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
+        return rv;
+      }
+      if (FTy->getParamType(0)->isPointerTy()) {
+        GenericValue rv;
+        int (*PF)(char *) = (int(*)(char *))(intptr_t)FPtr;
+        rv.IntVal = APInt(32, PF((char*)GVTOP(ArgValues[0])));
+        return rv;
+      }
+      break;
+    }
+  }
+
+  // Handle cases where no arguments are passed first.
+  if (ArgValues.empty()) {
+    GenericValue rv;
+    switch (RetTy->getTypeID()) {
+    default: llvm_unreachable("Unknown return type for function call!");
+    case Type::IntegerTyID: {
+      unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
+      if (BitWidth == 1)
+        rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 8)
+        rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 16)
+        rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 32)
+        rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 64)
+        rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
+      else
+        llvm_unreachable("Integer types > 64 bits not supported");
+      return rv;
+    }
+    case Type::VoidTyID:
+      rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
+      return rv;
+    case Type::FloatTyID:
+      rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
+      return rv;
+    case Type::DoubleTyID:
+      rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
+      return rv;
+    case Type::X86_FP80TyID:
+    case Type::FP128TyID:
+    case Type::PPC_FP128TyID:
+      llvm_unreachable("long double not supported yet");
+    case Type::PointerTyID:
+      return PTOGV(((void*(*)())(intptr_t)FPtr)());
+    }
+  }
+
+  // Okay, this is not one of our quick and easy cases.  Because we don't have a
+  // full FFI, we have to codegen a nullary stub function that just calls the
+  // function we are interested in, passing in constants for all of the
+  // arguments.  Make this function and return.
+
+  // First, create the function.
+  FunctionType *STy=FunctionType::get(RetTy, false);
+  Function *Stub = Function::Create(STy, Function::InternalLinkage, "",
+                                    F->getParent());
+
+  // Insert a basic block.
+  BasicBlock *StubBB = BasicBlock::Create(F->getContext(), "", Stub);
+
+  // Convert all of the GenericValue arguments over to constants.  Note that we
+  // currently don't support varargs.
+  SmallVector<Value*, 8> Args;
+  for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
+    Constant *C = nullptr;
+    Type *ArgTy = FTy->getParamType(i);
+    const GenericValue &AV = ArgValues[i];
+    switch (ArgTy->getTypeID()) {
+    default: llvm_unreachable("Unknown argument type for function call!");
+    case Type::IntegerTyID:
+        C = ConstantInt::get(F->getContext(), AV.IntVal);
+        break;
+    case Type::FloatTyID:
+        C = ConstantFP::get(F->getContext(), APFloat(AV.FloatVal));
+        break;
+    case Type::DoubleTyID:
+        C = ConstantFP::get(F->getContext(), APFloat(AV.DoubleVal));
+        break;
+    case Type::PPC_FP128TyID:
+    case Type::X86_FP80TyID:
+    case Type::FP128TyID:
+        C = ConstantFP::get(F->getContext(), APFloat(ArgTy->getFltSemantics(),
+                                                     AV.IntVal));
+        break;
+    case Type::PointerTyID:
+      void *ArgPtr = GVTOP(AV);
+      if (sizeof(void*) == 4)
+        C = ConstantInt::get(Type::getInt32Ty(F->getContext()),
+                             (int)(intptr_t)ArgPtr);
+      else
+        C = ConstantInt::get(Type::getInt64Ty(F->getContext()),
+                             (intptr_t)ArgPtr);
+      // Cast the integer to pointer
+      C = ConstantExpr::getIntToPtr(C, ArgTy);
+      break;
+    }
+    Args.push_back(C);
+  }
+
+  CallInst *TheCall = CallInst::Create(F, Args, "", StubBB);
+  TheCall->setCallingConv(F->getCallingConv());
+  TheCall->setTailCall();
+  if (!TheCall->getType()->isVoidTy())
+    // Return result of the call.
+    ReturnInst::Create(F->getContext(), TheCall, StubBB);
+  else
+    ReturnInst::Create(F->getContext(), StubBB);           // Just return void.
+
+  // Finally, call our nullary stub function.
+  GenericValue Result = runFunction(Stub, std::vector<GenericValue>());
+  // Erase it, since no other function can have a reference to it.
+  Stub->eraseFromParent();
+  // And return the result.
+  return Result;
+}
+
+void JIT::RegisterJITEventListener(JITEventListener *L) {
+  if (!L)
+    return;
+  MutexGuard locked(lock);
+  EventListeners.push_back(L);
+}
+void JIT::UnregisterJITEventListener(JITEventListener *L) {
+  if (!L)
+    return;
+  MutexGuard locked(lock);
+  std::vector<JITEventListener*>::reverse_iterator I=
+      std::find(EventListeners.rbegin(), EventListeners.rend(), L);
+  if (I != EventListeners.rend()) {
+    std::swap(*I, EventListeners.back());
+    EventListeners.pop_back();
+  }
+}
+void JIT::NotifyFunctionEmitted(
+    const Function &F,
+    void *Code, size_t Size,
+    const JITEvent_EmittedFunctionDetails &Details) {
+  MutexGuard locked(lock);
+  for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
+    EventListeners[I]->NotifyFunctionEmitted(F, Code, Size, Details);
+  }
+}
+
+void JIT::NotifyFreeingMachineCode(void *OldPtr) {
+  MutexGuard locked(lock);
+  for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
+    EventListeners[I]->NotifyFreeingMachineCode(OldPtr);
+  }
+}
+
+/// runJITOnFunction - Run the FunctionPassManager full of
+/// just-in-time compilation passes on F, hopefully filling in
+/// GlobalAddress[F] with the address of F's machine code.
+///
+void JIT::runJITOnFunction(Function *F, MachineCodeInfo *MCI) {
+  MutexGuard locked(lock);
+
+  class MCIListener : public JITEventListener {
+    MachineCodeInfo *const MCI;
+   public:
+    MCIListener(MachineCodeInfo *mci) : MCI(mci) {}
+    void NotifyFunctionEmitted(const Function &, void *Code, size_t Size,
+                               const EmittedFunctionDetails &) override {
+      MCI->setAddress(Code);
+      MCI->setSize(Size);
+    }
+  };
+  MCIListener MCIL(MCI);
+  if (MCI)
+    RegisterJITEventListener(&MCIL);
+
+  runJITOnFunctionUnlocked(F);
+
+  if (MCI)
+    UnregisterJITEventListener(&MCIL);
+}
+
+void JIT::runJITOnFunctionUnlocked(Function *F) {
+  assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
+
+  jitTheFunctionUnlocked(F);
+
+  // If the function referred to another function that had not yet been
+  // read from bitcode, and we are jitting non-lazily, emit it now.
+  while (!jitstate->getPendingFunctions().empty()) {
+    Function *PF = jitstate->getPendingFunctions().back();
+    jitstate->getPendingFunctions().pop_back();
+
+    assert(!PF->hasAvailableExternallyLinkage() &&
+           "Externally-defined function should not be in pending list.");
+
+    jitTheFunctionUnlocked(PF);
+
+    // Now that the function has been jitted, ask the JITEmitter to rewrite
+    // the stub with real address of the function.
+    updateFunctionStubUnlocked(PF);
+  }
+}
+
+void JIT::jitTheFunctionUnlocked(Function *F) {
+  isAlreadyCodeGenerating = true;
+  jitstate->getPM().run(*F);
+  isAlreadyCodeGenerating = false;
+
+  // clear basic block addresses after this function is done
+  getBasicBlockAddressMap().clear();
+}
+
+/// getPointerToFunction - This method is used to get the address of the
+/// specified function, compiling it if necessary.
+///
+void *JIT::getPointerToFunction(Function *F) {
+
+  if (void *Addr = getPointerToGlobalIfAvailable(F))
+    return Addr;   // Check if function already code gen'd
+
+  MutexGuard locked(lock);
+
+  // Now that this thread owns the lock, make sure we read in the function if it
+  // exists in this Module.
+  std::string ErrorMsg;
+  if (F->Materialize(&ErrorMsg)) {
+    report_fatal_error("Error reading function '" + F->getName()+
+                      "' from bitcode file: " + ErrorMsg);
+  }
+
+  // ... and check if another thread has already code gen'd the function.
+  if (void *Addr = getPointerToGlobalIfAvailable(F))
+    return Addr;
+
+  if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
+    bool AbortOnFailure = !F->hasExternalWeakLinkage();
+    void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
+    addGlobalMapping(F, Addr);
+    return Addr;
+  }
+
+  runJITOnFunctionUnlocked(F);
+
+  void *Addr = getPointerToGlobalIfAvailable(F);
+  assert(Addr && "Code generation didn't add function to GlobalAddress table!");
+  return Addr;
+}
+
+void JIT::addPointerToBasicBlock(const BasicBlock *BB, void *Addr) {
+  MutexGuard locked(lock);
+
+  BasicBlockAddressMapTy::iterator I =
+    getBasicBlockAddressMap().find(BB);
+  if (I == getBasicBlockAddressMap().end()) {
+    getBasicBlockAddressMap()[BB] = Addr;
+  } else {
+    // ignore repeats: some BBs can be split into few MBBs?
+  }
+}
+
+void JIT::clearPointerToBasicBlock(const BasicBlock *BB) {
+  MutexGuard locked(lock);
+  getBasicBlockAddressMap().erase(BB);
+}
+
+void *JIT::getPointerToBasicBlock(BasicBlock *BB) {
+  // make sure it's function is compiled by JIT
+  (void)getPointerToFunction(BB->getParent());
+
+  // resolve basic block address
+  MutexGuard locked(lock);
+
+  BasicBlockAddressMapTy::iterator I =
+    getBasicBlockAddressMap().find(BB);
+  if (I != getBasicBlockAddressMap().end()) {
+    return I->second;
+  } else {
+    llvm_unreachable("JIT does not have BB address for address-of-label, was"
+                     " it eliminated by optimizer?");
+  }
+}
+
+void *JIT::getPointerToNamedFunction(const std::string &Name,
+                                     bool AbortOnFailure){
+  if (!isSymbolSearchingDisabled()) {
+    void *ptr = JMM->getPointerToNamedFunction(Name, false);
+    if (ptr)
+      return ptr;
+  }
+
+  /// If a LazyFunctionCreator is installed, use it to get/create the function.
+  if (LazyFunctionCreator)
+    if (void *RP = LazyFunctionCreator(Name))
+      return RP;
+
+  if (AbortOnFailure) {
+    report_fatal_error("Program used external function '"+Name+
+                      "' which could not be resolved!");
+  }
+  return nullptr;
+}
+
+
+/// getOrEmitGlobalVariable - Return the address of the specified global
+/// variable, possibly emitting it to memory if needed.  This is used by the
+/// Emitter.
+void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
+  MutexGuard locked(lock);
+
+  void *Ptr = getPointerToGlobalIfAvailable(GV);
+  if (Ptr) return Ptr;
+
+  // If the global is external, just remember the address.
+  if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) {
+#if HAVE___DSO_HANDLE
+    if (GV->getName() == "__dso_handle")
+      return (void*)&__dso_handle;
+#endif
+    Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName());
+    if (!Ptr) {
+      report_fatal_error("Could not resolve external global address: "
+                        +GV->getName());
+    }
+    addGlobalMapping(GV, Ptr);
+  } else {
+    // If the global hasn't been emitted to memory yet, allocate space and
+    // emit it into memory.
+    Ptr = getMemoryForGV(GV);
+    addGlobalMapping(GV, Ptr);
+    EmitGlobalVariable(GV);  // Initialize the variable.
+  }
+  return Ptr;
+}
+
+/// recompileAndRelinkFunction - This method is used to force a function
+/// which has already been compiled, to be compiled again, possibly
+/// after it has been modified. Then the entry to the old copy is overwritten
+/// with a branch to the new copy. If there was no old copy, this acts
+/// just like JIT::getPointerToFunction().
+///
+void *JIT::recompileAndRelinkFunction(Function *F) {
+  void *OldAddr = getPointerToGlobalIfAvailable(F);
+
+  // If it's not already compiled there is no reason to patch it up.
+  if (!OldAddr) return getPointerToFunction(F);
+
+  // Delete the old function mapping.
+  addGlobalMapping(F, nullptr);
+
+  // Recodegen the function
+  runJITOnFunction(F);
+
+  // Update state, forward the old function to the new function.
+  void *Addr = getPointerToGlobalIfAvailable(F);
+  assert(Addr && "Code generation didn't add function to GlobalAddress table!");
+  TJI.replaceMachineCodeForFunction(OldAddr, Addr);
+  return Addr;
+}
+
+/// getMemoryForGV - This method abstracts memory allocation of global
+/// variable so that the JIT can allocate thread local variables depending
+/// on the target.
+///
+char* JIT::getMemoryForGV(const GlobalVariable* GV) {
+  char *Ptr;
+
+  // GlobalVariable's which are not "constant" will cause trouble in a server
+  // situation. It's returned in the same block of memory as code which may
+  // not be writable.
+  if (isGVCompilationDisabled() && !GV->isConstant()) {
+    report_fatal_error("Compilation of non-internal GlobalValue is disabled!");
+  }
+
+  // Some applications require globals and code to live together, so they may
+  // be allocated into the same buffer, but in general globals are allocated
+  // through the memory manager which puts them near the code but not in the
+  // same buffer.
+  Type *GlobalType = GV->getType()->getElementType();
+  size_t S = getDataLayout()->getTypeAllocSize(GlobalType);
+  size_t A = getDataLayout()->getPreferredAlignment(GV);
+  if (GV->isThreadLocal()) {
+    MutexGuard locked(lock);
+    Ptr = TJI.allocateThreadLocalMemory(S);
+  } else if (TJI.allocateSeparateGVMemory()) {
+    if (A <= 8) {
+      Ptr = (char*)malloc(S);
+    } else {
+      // Allocate S+A bytes of memory, then use an aligned pointer within that
+      // space.
+      Ptr = (char*)malloc(S+A);
+      unsigned MisAligned = ((intptr_t)Ptr & (A-1));
+      Ptr = Ptr + (MisAligned ? (A-MisAligned) : 0);
+    }
+  } else if (AllocateGVsWithCode) {
+    Ptr = (char*)JCE->allocateSpace(S, A);
+  } else {
+    Ptr = (char*)JCE->allocateGlobal(S, A);
+  }
+  return Ptr;
+}
+
+void JIT::addPendingFunction(Function *F) {
+  MutexGuard locked(lock);
+  jitstate->getPendingFunctions().push_back(F);
+}
+
+
+JITEventListener::~JITEventListener() {}
diff --git a/llvm/lib/ExecutionEngine/JIT/JIT.h b/llvm/lib/ExecutionEngine/JIT/JIT.h
new file mode 100644
index 00000000000..a742a61de7f
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JIT/JIT.h
@@ -0,0 +1,214 @@
+//===-- JIT.h - Class definition for the JIT --------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the top-level JIT data structure.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef JIT_H
+#define JIT_H
+
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/PassManager.h"
+
+namespace llvm {
+
+class Function;
+struct JITEvent_EmittedFunctionDetails;
+class MachineCodeEmitter;
+class MachineCodeInfo;
+class TargetJITInfo;
+class TargetMachine;
+
+class JITState {
+private:
+  FunctionPassManager PM;  // Passes to compile a function
+  Module *M;               // Module used to create the PM
+
+  /// PendingFunctions - Functions which have not been code generated yet, but
+  /// were called from a function being code generated.
+  std::vector<AssertingVH<Function> > PendingFunctions;
+
+public:
+  explicit JITState(Module *M) : PM(M), M(M) {}
+
+  FunctionPassManager &getPM() {
+    return PM;
+  }
+
+  Module *getModule() const { return M; }
+  std::vector<AssertingVH<Function> > &getPendingFunctions() {
+    return PendingFunctions;
+  }
+};
+
+
+class JIT : public ExecutionEngine {
+  /// types
+  typedef ValueMap<const BasicBlock *, void *>
+      BasicBlockAddressMapTy;
+  /// data
+  TargetMachine &TM;       // The current target we are compiling to
+  TargetJITInfo &TJI;      // The JITInfo for the target we are compiling to
+  JITCodeEmitter *JCE;     // JCE object
+  JITMemoryManager *JMM;
+  std::vector<JITEventListener*> EventListeners;
+
+  /// AllocateGVsWithCode - Some applications require that global variables and
+  /// code be allocated into the same region of memory, in which case this flag
+  /// should be set to true.  Doing so breaks freeMachineCodeForFunction.
+  bool AllocateGVsWithCode;
+
+  /// True while the JIT is generating code.  Used to assert against recursive
+  /// entry.
+  bool isAlreadyCodeGenerating;
+
+  JITState *jitstate;
+
+  /// BasicBlockAddressMap - A mapping between LLVM basic blocks and their
+  /// actualized version, only filled for basic blocks that have their address
+  /// taken.
+  BasicBlockAddressMapTy BasicBlockAddressMap;
+
+
+  JIT(Module *M, TargetMachine &tm, TargetJITInfo &tji,
+      JITMemoryManager *JMM, bool AllocateGVsWithCode);
+public:
+  ~JIT();
+
+  static void Register() {
+    JITCtor = createJIT;
+  }
+
+  /// getJITInfo - Return the target JIT information structure.
+  ///
+  TargetJITInfo &getJITInfo() const { return TJI; }
+
+  void addModule(Module *M) override;
+
+  /// removeModule - Remove a Module from the list of modules.  Returns true if
+  /// M is found.
+  bool removeModule(Module *M) override;
+
+  /// runFunction - Start execution with the specified function and arguments.
+  ///
+  GenericValue runFunction(Function *F,
+                           const std::vector<GenericValue> &ArgValues) override;
+
+  /// getPointerToNamedFunction - This method returns the address of the
+  /// specified function by using the MemoryManager. As such it is only
+  /// useful for resolving library symbols, not code generated symbols.
+  ///
+  /// If AbortOnFailure is false and no function with the given name is
+  /// found, this function silently returns a null pointer. Otherwise,
+  /// it prints a message to stderr and aborts.
+  ///
+  void *getPointerToNamedFunction(const std::string &Name,
+                                  bool AbortOnFailure = true) override;
+
+  // CompilationCallback - Invoked the first time that a call site is found,
+  // which causes lazy compilation of the target function.
+  //
+  static void CompilationCallback();
+
+  /// getPointerToFunction - This returns the address of the specified function,
+  /// compiling it if necessary.
+  ///
+  void *getPointerToFunction(Function *F) override;
+
+  /// addPointerToBasicBlock - Adds address of the specific basic block.
+  void addPointerToBasicBlock(const BasicBlock *BB, void *Addr);
+
+  /// clearPointerToBasicBlock - Removes address of specific basic block.
+  void clearPointerToBasicBlock(const BasicBlock *BB);
+
+  /// getPointerToBasicBlock - This returns the address of the specified basic
+  /// block, assuming function is compiled.
+  void *getPointerToBasicBlock(BasicBlock *BB) override;
+
+  /// getOrEmitGlobalVariable - Return the address of the specified global
+  /// variable, possibly emitting it to memory if needed.  This is used by the
+  /// Emitter.
+  void *getOrEmitGlobalVariable(const GlobalVariable *GV) override;
+
+  /// getPointerToFunctionOrStub - If the specified function has been
+  /// code-gen'd, return a pointer to the function.  If not, compile it, or use
+  /// a stub to implement lazy compilation if available.
+  ///
+  void *getPointerToFunctionOrStub(Function *F) override;
+
+  /// recompileAndRelinkFunction - This method is used to force a function
+  /// which has already been compiled, to be compiled again, possibly
+  /// after it has been modified. Then the entry to the old copy is overwritten
+  /// with a branch to the new copy. If there was no old copy, this acts
+  /// just like JIT::getPointerToFunction().
+  ///
+  void *recompileAndRelinkFunction(Function *F) override;
+
+  /// freeMachineCodeForFunction - deallocate memory used to code-generate this
+  /// Function.
+  ///
+  void freeMachineCodeForFunction(Function *F) override;
+
+  /// addPendingFunction - while jitting non-lazily, a called but non-codegen'd
+  /// function was encountered.  Add it to a pending list to be processed after
+  /// the current function.
+  ///
+  void addPendingFunction(Function *F);
+
+  /// getCodeEmitter - Return the code emitter this JIT is emitting into.
+  ///
+  JITCodeEmitter *getCodeEmitter() const { return JCE; }
+
+  static ExecutionEngine *createJIT(Module *M,
+                                    std::string *ErrorStr,
+                                    JITMemoryManager *JMM,
+                                    bool GVsWithCode,
+                                    TargetMachine *TM);
+
+  // Run the JIT on F and return information about the generated code
+  void runJITOnFunction(Function *F, MachineCodeInfo *MCI = nullptr) override;
+
+  void RegisterJITEventListener(JITEventListener *L) override;
+  void UnregisterJITEventListener(JITEventListener *L) override;
+
+  TargetMachine *getTargetMachine() override { return &TM; }
+
+  /// These functions correspond to the methods on JITEventListener.  They
+  /// iterate over the registered listeners and call the corresponding method on
+  /// each.
+  void NotifyFunctionEmitted(
+      const Function &F, void *Code, size_t Size,
+      const JITEvent_EmittedFunctionDetails &Details);
+  void NotifyFreeingMachineCode(void *OldPtr);
+
+  BasicBlockAddressMapTy &
+  getBasicBlockAddressMap() {
+    return BasicBlockAddressMap;
+  }
+
+
+private:
+  static JITCodeEmitter *createEmitter(JIT &J, JITMemoryManager *JMM,
+                                       TargetMachine &tm);
+  void runJITOnFunctionUnlocked(Function *F);
+  void updateFunctionStubUnlocked(Function *F);
+  void jitTheFunctionUnlocked(Function *F);
+
+protected:
+
+  /// getMemoryforGV - Allocate memory for a global variable.
+  char* getMemoryForGV(const GlobalVariable* GV) override;
+
+};
+
+} // End llvm namespace
+
+#endif
diff --git a/llvm/lib/ExecutionEngine/JIT/JITEmitter.cpp b/llvm/lib/ExecutionEngine/JIT/JITEmitter.cpp
new file mode 100644
index 00000000000..2ba1f8695d7
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -0,0 +1,1249 @@
+//===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a MachineCodeEmitter object that is used by the JIT to
+// write machine code to memory and remember where relocatable values are.
+//
+//===----------------------------------------------------------------------===//
+
+#include "JIT.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/JITCodeEmitter.h"
+#include "llvm/CodeGen/MachineCodeInfo.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRelocation.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ExecutionEngine/JITEventListener.h"
+#include "llvm/ExecutionEngine/JITMemoryManager.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/IR/ValueMap.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Memory.h"
+#include "llvm/Support/MutexGuard.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetJITInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include <algorithm>
+#ifndef NDEBUG
+#include <iomanip>
+#endif
+using namespace llvm;
+
+#define DEBUG_TYPE "jit"
+
+STATISTIC(NumBytes, "Number of bytes of machine code compiled");
+STATISTIC(NumRelos, "Number of relocations applied");
+STATISTIC(NumRetries, "Number of retries with more memory");
+
+
+// A declaration may stop being a declaration once it's fully read from bitcode.
+// This function returns true if F is fully read and is still a declaration.
+static bool isNonGhostDeclaration(const Function *F) {
+  return F->isDeclaration() && !F->isMaterializable();
+}
+
+//===----------------------------------------------------------------------===//
+// JIT lazy compilation code.
+//
+namespace {
+  class JITEmitter;
+  class JITResolverState;
+
+  template<typename ValueTy>
+  struct NoRAUWValueMapConfig : public ValueMapConfig<ValueTy> {
+    typedef JITResolverState *ExtraData;
+    static void onRAUW(JITResolverState *, Value *Old, Value *New) {
+      llvm_unreachable("The JIT doesn't know how to handle a"
+                       " RAUW on a value it has emitted.");
+    }
+  };
+
+  struct CallSiteValueMapConfig : public NoRAUWValueMapConfig<Function*> {
+    typedef JITResolverState *ExtraData;
+    static void onDelete(JITResolverState *JRS, Function *F);
+  };
+
+  class JITResolverState {
+  public:
+    typedef ValueMap<Function*, void*, NoRAUWValueMapConfig<Function*> >
+      FunctionToLazyStubMapTy;
+    typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy;
+    typedef ValueMap<Function *, SmallPtrSet<void*, 1>,
+                     CallSiteValueMapConfig> FunctionToCallSitesMapTy;
+    typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
+  private:
+    /// FunctionToLazyStubMap - Keep track of the lazy stub created for a
+    /// particular function so that we can reuse them if necessary.
+    FunctionToLazyStubMapTy FunctionToLazyStubMap;
+
+    /// CallSiteToFunctionMap - Keep track of the function that each lazy call
+    /// site corresponds to, and vice versa.
+    CallSiteToFunctionMapTy CallSiteToFunctionMap;
+    FunctionToCallSitesMapTy FunctionToCallSitesMap;
+
+    /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
+    /// particular GlobalVariable so that we can reuse them if necessary.
+    GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
+
+#ifndef NDEBUG
+    /// Instance of the JIT this ResolverState serves.
+    JIT *TheJIT;
+#endif
+
+  public:
+    JITResolverState(JIT *jit) : FunctionToLazyStubMap(this),
+                                 FunctionToCallSitesMap(this) {
+#ifndef NDEBUG
+      TheJIT = jit;
+#endif
+    }
+
+    FunctionToLazyStubMapTy& getFunctionToLazyStubMap() {
+      return FunctionToLazyStubMap;
+    }
+
+    GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap() {
+      return GlobalToIndirectSymMap;
+    }
+
+    std::pair<void *, Function *> LookupFunctionFromCallSite(
+        void *CallSite) const {
+      // The address given to us for the stub may not be exactly right, it
+      // might be a little bit after the stub.  As such, use upper_bound to
+      // find it.
+      CallSiteToFunctionMapTy::const_iterator I =
+        CallSiteToFunctionMap.upper_bound(CallSite);
+      assert(I != CallSiteToFunctionMap.begin() &&
+             "This is not a known call site!");
+      --I;
+      return *I;
+    }
+
+    void AddCallSite(void *CallSite, Function *F) {
+      bool Inserted = CallSiteToFunctionMap.insert(
+          std::make_pair(CallSite, F)).second;
+      (void)Inserted;
+      assert(Inserted && "Pair was already in CallSiteToFunctionMap");
+      FunctionToCallSitesMap[F].insert(CallSite);
+    }
+
+    void EraseAllCallSitesForPrelocked(Function *F);
+
+    // Erases _all_ call sites regardless of their function.  This is used to
+    // unregister the stub addresses from the StubToResolverMap in
+    // ~JITResolver().
+    void EraseAllCallSitesPrelocked();
+  };
+
+  /// JITResolver - Keep track of, and resolve, call sites for functions that
+  /// have not yet been compiled.
+  class JITResolver {
+    typedef JITResolverState::FunctionToLazyStubMapTy FunctionToLazyStubMapTy;
+    typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy;
+    typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
+
+    /// LazyResolverFn - The target lazy resolver function that we actually
+    /// rewrite instructions to use.
+    TargetJITInfo::LazyResolverFn LazyResolverFn;
+
+    JITResolverState state;
+
+    /// ExternalFnToStubMap - This is the equivalent of FunctionToLazyStubMap
+    /// for external functions.  TODO: Of course, external functions don't need
+    /// a lazy stub.  It's actually here to make it more likely that far calls
+    /// succeed, but no single stub can guarantee that.  I'll remove this in a
+    /// subsequent checkin when I actually fix far calls.
+    std::map<void*, void*> ExternalFnToStubMap;
+
+    /// revGOTMap - map addresses to indexes in the GOT
+    std::map<void*, unsigned> revGOTMap;
+    unsigned nextGOTIndex;
+
+    JITEmitter &JE;
+
+    /// Instance of JIT corresponding to this Resolver.
+    JIT *TheJIT;
+
+  public:
+    explicit JITResolver(JIT &jit, JITEmitter &je)
+      : state(&jit), nextGOTIndex(0), JE(je), TheJIT(&jit) {
+      LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
+    }
+
+    ~JITResolver();
+
+    /// getLazyFunctionStubIfAvailable - This returns a pointer to a function's
+    /// lazy-compilation stub if it has already been created.
+    void *getLazyFunctionStubIfAvailable(Function *F);
+
+    /// getLazyFunctionStub - This returns a pointer to a function's
+    /// lazy-compilation stub, creating one on demand as needed.
+    void *getLazyFunctionStub(Function *F);
+
+    /// getExternalFunctionStub - Return a stub for the function at the
+    /// specified address, created lazily on demand.
+    void *getExternalFunctionStub(void *FnAddr);
+
+    /// getGlobalValueIndirectSym - Return an indirect symbol containing the
+    /// specified GV address.
+    void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
+
+    /// getGOTIndexForAddress - Return a new or existing index in the GOT for
+    /// an address.  This function only manages slots, it does not manage the
+    /// contents of the slots or the memory associated with the GOT.
+    unsigned getGOTIndexForAddr(void *addr);
+
+    /// JITCompilerFn - This function is called to resolve a stub to a compiled
+    /// address.  If the LLVM Function corresponding to the stub has not yet
+    /// been compiled, this function compiles it first.
+    static void *JITCompilerFn(void *Stub);
+  };
+
+  class StubToResolverMapTy {
+    /// Map a stub address to a specific instance of a JITResolver so that
+    /// lazily-compiled functions can find the right resolver to use.
+    ///
+    /// Guarded by Lock.
+    std::map<void*, JITResolver*> Map;
+
+    /// Guards Map from concurrent accesses.
+    mutable sys::Mutex Lock;
+
+  public:
+    /// Registers a Stub to be resolved by Resolver.
+    void RegisterStubResolver(void *Stub, JITResolver *Resolver) {
+      MutexGuard guard(Lock);
+      Map.insert(std::make_pair(Stub, Resolver));
+    }
+    /// Unregisters the Stub when it's invalidated.
+    void UnregisterStubResolver(void *Stub) {
+      MutexGuard guard(Lock);
+      Map.erase(Stub);
+    }
+    /// Returns the JITResolver instance that owns the Stub.
+    JITResolver *getResolverFromStub(void *Stub) const {
+      MutexGuard guard(Lock);
+      // The address given to us for the stub may not be exactly right, it might
+      // be a little bit after the stub.  As such, use upper_bound to find it.
+      // This is the same trick as in LookupFunctionFromCallSite from
+      // JITResolverState.
+      std::map<void*, JITResolver*>::const_iterator I = Map.upper_bound(Stub);
+      assert(I != Map.begin() && "This is not a known stub!");
+      --I;
+      return I->second;
+    }
+    /// True if any stubs refer to the given resolver. Only used in an assert().
+    /// O(N)
+    bool ResolverHasStubs(JITResolver* Resolver) const {
+      MutexGuard guard(Lock);
+      for (std::map<void*, JITResolver*>::const_iterator I = Map.begin(),
+             E = Map.end(); I != E; ++I) {
+        if (I->second == Resolver)
+          return true;
+      }
+      return false;
+    }
+  };
+  /// This needs to be static so that a lazy call stub can access it with no
+  /// context except the address of the stub.
+  ManagedStatic<StubToResolverMapTy> StubToResolverMap;
+
+  /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
+  /// used to output functions to memory for execution.
+  class JITEmitter : public JITCodeEmitter {
+    JITMemoryManager *MemMgr;
+
+    // When outputting a function stub in the context of some other function, we
+    // save BufferBegin/BufferEnd/CurBufferPtr here.
+    uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
+
+    // When reattempting to JIT a function after running out of space, we store
+    // the estimated size of the function we're trying to JIT here, so we can
+    // ask the memory manager for at least this much space.  When we
+    // successfully emit the function, we reset this back to zero.
+    uintptr_t SizeEstimate;
+
+    /// Relocations - These are the relocations that the function needs, as
+    /// emitted.
+    std::vector<MachineRelocation> Relocations;
+
+    /// MBBLocations - This vector is a mapping from MBB ID's to their address.
+    /// It is filled in by the StartMachineBasicBlock callback and queried by
+    /// the getMachineBasicBlockAddress callback.
+    std::vector<uintptr_t> MBBLocations;
+
+    /// ConstantPool - The constant pool for the current function.
+    ///
+    MachineConstantPool *ConstantPool;
+
+    /// ConstantPoolBase - A pointer to the first entry in the constant pool.
+    ///
+    void *ConstantPoolBase;
+
+    /// ConstPoolAddresses - Addresses of individual constant pool entries.
+    ///
+    SmallVector<uintptr_t, 8> ConstPoolAddresses;
+
+    /// JumpTable - The jump tables for the current function.
+    ///
+    MachineJumpTableInfo *JumpTable;
+
+    /// JumpTableBase - A pointer to the first entry in the jump table.
+    ///
+    void *JumpTableBase;
+
+    /// Resolver - This contains info about the currently resolved functions.
+    JITResolver Resolver;
+
+    /// LabelLocations - This vector is a mapping from Label ID's to their
+    /// address.
+    DenseMap<MCSymbol*, uintptr_t> LabelLocations;
+
+    /// MMI - Machine module info for exception informations
+    MachineModuleInfo* MMI;
+
+    // CurFn - The llvm function being emitted.  Only valid during
+    // finishFunction().
+    const Function *CurFn;
+
+    /// Information about emitted code, which is passed to the
+    /// JITEventListeners.  This is reset in startFunction and used in
+    /// finishFunction.
+    JITEvent_EmittedFunctionDetails EmissionDetails;
+
+    struct EmittedCode {
+      void *FunctionBody;  // Beginning of the function's allocation.
+      void *Code;  // The address the function's code actually starts at.
+      void *ExceptionTable;
+      EmittedCode() : FunctionBody(nullptr), Code(nullptr),
+                      ExceptionTable(nullptr) {}
+    };
+    struct EmittedFunctionConfig : public ValueMapConfig<const Function*> {
+      typedef JITEmitter *ExtraData;
+      static void onDelete(JITEmitter *, const Function*);
+      static void onRAUW(JITEmitter *, const Function*, const Function*);
+    };
+    ValueMap<const Function *, EmittedCode,
+             EmittedFunctionConfig> EmittedFunctions;
+
+    DebugLoc PrevDL;
+
+    /// Instance of the JIT
+    JIT *TheJIT;
+
+  public:
+    JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM)
+      : SizeEstimate(0), Resolver(jit, *this), MMI(nullptr), CurFn(nullptr),
+        EmittedFunctions(this), TheJIT(&jit) {
+      MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
+      if (jit.getJITInfo().needsGOT()) {
+        MemMgr->AllocateGOT();
+        DEBUG(dbgs() << "JIT is managing a GOT\n");
+      }
+
+    }
+    ~JITEmitter() {
+      delete MemMgr;
+    }
+
+    JITResolver &getJITResolver() { return Resolver; }
+
+    void startFunction(MachineFunction &F) override;
+    bool finishFunction(MachineFunction &F) override;
+
+    void emitConstantPool(MachineConstantPool *MCP);
+    void initJumpTableInfo(MachineJumpTableInfo *MJTI);
+    void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
+
+    void startGVStub(const GlobalValue* GV,
+                     unsigned StubSize, unsigned Alignment = 1);
+    void startGVStub(void *Buffer, unsigned StubSize);
+    void finishGVStub();
+    void *allocIndirectGV(const GlobalValue *GV, const uint8_t *Buffer,
+                          size_t Size, unsigned Alignment) override;
+
+    /// allocateSpace - Reserves space in the current block if any, or
+    /// allocate a new one of the given size.
+    void *allocateSpace(uintptr_t Size, unsigned Alignment) override;
+
+    /// allocateGlobal - Allocate memory for a global.  Unlike allocateSpace,
+    /// this method does not allocate memory in the current output buffer,
+    /// because a global may live longer than the current function.
+    void *allocateGlobal(uintptr_t Size, unsigned Alignment) override;
+
+    void addRelocation(const MachineRelocation &MR) override {
+      Relocations.push_back(MR);
+    }
+
+    void StartMachineBasicBlock(MachineBasicBlock *MBB) override {
+      if (MBBLocations.size() <= (unsigned)MBB->getNumber())
+        MBBLocations.resize((MBB->getNumber()+1)*2);
+      MBBLocations[MBB->getNumber()] = getCurrentPCValue();
+      if (MBB->hasAddressTaken())
+        TheJIT->addPointerToBasicBlock(MBB->getBasicBlock(),
+                                       (void*)getCurrentPCValue());
+      DEBUG(dbgs() << "JIT: Emitting BB" << MBB->getNumber() << " at ["
+                   << (void*) getCurrentPCValue() << "]\n");
+    }
+
+    uintptr_t getConstantPoolEntryAddress(unsigned Entry) const override;
+    uintptr_t getJumpTableEntryAddress(unsigned Entry) const override;
+
+    uintptr_t
+    getMachineBasicBlockAddress(MachineBasicBlock *MBB) const override {
+      assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
+             MBBLocations[MBB->getNumber()] && "MBB not emitted!");
+      return MBBLocations[MBB->getNumber()];
+    }
+
+    /// retryWithMoreMemory - Log a retry and deallocate all memory for the
+    /// given function.  Increase the minimum allocation size so that we get
+    /// more memory next time.
+    void retryWithMoreMemory(MachineFunction &F);
+
+    /// deallocateMemForFunction - Deallocate all memory for the specified
+    /// function body.
+    void deallocateMemForFunction(const Function *F);
+
+    void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) override;
+
+    void emitLabel(MCSymbol *Label) override {
+      LabelLocations[Label] = getCurrentPCValue();
+    }
+
+    DenseMap<MCSymbol*, uintptr_t> *getLabelLocations() override {
+      return &LabelLocations;
+    }
+
+    uintptr_t getLabelAddress(MCSymbol *Label) const override {
+      assert(LabelLocations.count(Label) && "Label not emitted!");
+      return LabelLocations.find(Label)->second;
+    }
+
+    void setModuleInfo(MachineModuleInfo* Info) override {
+      MMI = Info;
+    }
+
+  private:
+    void *getPointerToGlobal(GlobalValue *GV, void *Reference,
+                             bool MayNeedFarStub);
+    void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference);
+  };
+}
+
+void CallSiteValueMapConfig::onDelete(JITResolverState *JRS, Function *F) {
+  JRS->EraseAllCallSitesForPrelocked(F);
+}
+
+void JITResolverState::EraseAllCallSitesForPrelocked(Function *F) {
+  FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F);
+  if (F2C == FunctionToCallSitesMap.end())
+    return;
+  StubToResolverMapTy &S2RMap = *StubToResolverMap;
+  for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(),
+         E = F2C->second.end(); I != E; ++I) {
+    S2RMap.UnregisterStubResolver(*I);
+    bool Erased = CallSiteToFunctionMap.erase(*I);
+    (void)Erased;
+    assert(Erased && "Missing call site->function mapping");
+  }
+  FunctionToCallSitesMap.erase(F2C);
+}
+
+void JITResolverState::EraseAllCallSitesPrelocked() {
+  StubToResolverMapTy &S2RMap = *StubToResolverMap;
+  for (CallSiteToFunctionMapTy::const_iterator
+         I = CallSiteToFunctionMap.begin(),
+         E = CallSiteToFunctionMap.end(); I != E; ++I) {
+    S2RMap.UnregisterStubResolver(I->first);
+  }
+  CallSiteToFunctionMap.clear();
+  FunctionToCallSitesMap.clear();
+}
+
+JITResolver::~JITResolver() {
+  // No need to lock because we're in the destructor, and state isn't shared.
+  state.EraseAllCallSitesPrelocked();
+  assert(!StubToResolverMap->ResolverHasStubs(this) &&
+         "Resolver destroyed with stubs still alive.");
+}
+
+/// getLazyFunctionStubIfAvailable - This returns a pointer to a function stub
+/// if it has already been created.
+void *JITResolver::getLazyFunctionStubIfAvailable(Function *F) {
+  MutexGuard locked(TheJIT->lock);
+
+  // If we already have a stub for this function, recycle it.
+  return state.getFunctionToLazyStubMap().lookup(F);
+}
+
+/// getFunctionStub - This returns a pointer to a function stub, creating
+/// one on demand as needed.
+void *JITResolver::getLazyFunctionStub(Function *F) {
+  MutexGuard locked(TheJIT->lock);
+
+  // If we already have a lazy stub for this function, recycle it.
+  void *&Stub = state.getFunctionToLazyStubMap()[F];
+  if (Stub) return Stub;
+
+  // Call the lazy resolver function if we are JIT'ing lazily.  Otherwise we
+  // must resolve the symbol now.
+  void *Actual = TheJIT->isCompilingLazily()
+    ? (void *)(intptr_t)LazyResolverFn : (void *)nullptr;
+
+  // If this is an external declaration, attempt to resolve the address now
+  // to place in the stub.
+  if (isNonGhostDeclaration(F) || F->hasAvailableExternallyLinkage()) {
+    Actual = TheJIT->getPointerToFunction(F);
+
+    // If we resolved the symbol to a null address (eg. a weak external)
+    // don't emit a stub. Return a null pointer to the application.
+    if (!Actual) return nullptr;
+  }
+
+  TargetJITInfo::StubLayout SL = TheJIT->getJITInfo().getStubLayout();
+  JE.startGVStub(F, SL.Size, SL.Alignment);
+  // Codegen a new stub, calling the lazy resolver or the actual address of the
+  // external function, if it was resolved.
+  Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual, JE);
+  JE.finishGVStub();
+
+  if (Actual != (void*)(intptr_t)LazyResolverFn) {
+    // If we are getting the stub for an external function, we really want the
+    // address of the stub in the GlobalAddressMap for the JIT, not the address
+    // of the external function.
+    TheJIT->updateGlobalMapping(F, Stub);
+  }
+
+  DEBUG(dbgs() << "JIT: Lazy stub emitted at [" << Stub << "] for function '"
+        << F->getName() << "'\n");
+
+  if (TheJIT->isCompilingLazily()) {
+    // Register this JITResolver as the one corresponding to this call site so
+    // JITCompilerFn will be able to find it.
+    StubToResolverMap->RegisterStubResolver(Stub, this);
+
+    // Finally, keep track of the stub-to-Function mapping so that the
+    // JITCompilerFn knows which function to compile!
+    state.AddCallSite(Stub, F);
+  } else if (!Actual) {
+    // If we are JIT'ing non-lazily but need to call a function that does not
+    // exist yet, add it to the JIT's work list so that we can fill in the
+    // stub address later.
+    assert(!isNonGhostDeclaration(F) && !F->hasAvailableExternallyLinkage() &&
+           "'Actual' should have been set above.");
+    TheJIT->addPendingFunction(F);
+  }
+
+  return Stub;
+}
+
+/// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
+/// GV address.
+void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
+  MutexGuard locked(TheJIT->lock);
+
+  // If we already have a stub for this global variable, recycle it.
+  void *&IndirectSym = state.getGlobalToIndirectSymMap()[GV];
+  if (IndirectSym) return IndirectSym;
+
+  // Otherwise, codegen a new indirect symbol.
+  IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
+                                                                JE);
+
+  DEBUG(dbgs() << "JIT: Indirect symbol emitted at [" << IndirectSym
+        << "] for GV '" << GV->getName() << "'\n");
+
+  return IndirectSym;
+}
+
+/// getExternalFunctionStub - Return a stub for the function at the
+/// specified address, created lazily on demand.
+void *JITResolver::getExternalFunctionStub(void *FnAddr) {
+  // If we already have a stub for this function, recycle it.
+  void *&Stub = ExternalFnToStubMap[FnAddr];
+  if (Stub) return Stub;
+
+  TargetJITInfo::StubLayout SL = TheJIT->getJITInfo().getStubLayout();
+  JE.startGVStub(nullptr, SL.Size, SL.Alignment);
+  Stub = TheJIT->getJITInfo().emitFunctionStub(nullptr, FnAddr, JE);
+  JE.finishGVStub();
+
+  DEBUG(dbgs() << "JIT: Stub emitted at [" << Stub
+               << "] for external function at '" << FnAddr << "'\n");
+  return Stub;
+}
+
+unsigned JITResolver::getGOTIndexForAddr(void* addr) {
+  unsigned idx = revGOTMap[addr];
+  if (!idx) {
+    idx = ++nextGOTIndex;
+    revGOTMap[addr] = idx;
+    DEBUG(dbgs() << "JIT: Adding GOT entry " << idx << " for addr ["
+                 << addr << "]\n");
+  }
+  return idx;
+}
+
+/// JITCompilerFn - This function is called when a lazy compilation stub has
+/// been entered.  It looks up which function this stub corresponds to, compiles
+/// it if necessary, then returns the resultant function pointer.
+void *JITResolver::JITCompilerFn(void *Stub) {
+  JITResolver *JR = StubToResolverMap->getResolverFromStub(Stub);
+  assert(JR && "Unable to find the corresponding JITResolver to the call site");
+
+  Function* F = nullptr;
+  void* ActualPtr = nullptr;
+
+  {
+    // Only lock for getting the Function. The call getPointerToFunction made
+    // in this function might trigger function materializing, which requires
+    // JIT lock to be unlocked.
+    MutexGuard locked(JR->TheJIT->lock);
+
+    // The address given to us for the stub may not be exactly right, it might
+    // be a little bit after the stub.  As such, use upper_bound to find it.
+    std::pair<void*, Function*> I =
+      JR->state.LookupFunctionFromCallSite(Stub);
+    F = I.second;
+    ActualPtr = I.first;
+  }
+
+  // If we have already code generated the function, just return the address.
+  void *Result = JR->TheJIT->getPointerToGlobalIfAvailable(F);
+
+  if (!Result) {
+    // Otherwise we don't have it, do lazy compilation now.
+
+    // If lazy compilation is disabled, emit a useful error message and abort.
+    if (!JR->TheJIT->isCompilingLazily()) {
+      report_fatal_error("LLVM JIT requested to do lazy compilation of"
+                         " function '"
+                        + F->getName() + "' when lazy compiles are disabled!");
+    }
+
+    DEBUG(dbgs() << "JIT: Lazily resolving function '" << F->getName()
+          << "' In stub ptr = " << Stub << " actual ptr = "
+          << ActualPtr << "\n");
+    (void)ActualPtr;
+
+    Result = JR->TheJIT->getPointerToFunction(F);
+  }
+
+  // Reacquire the lock to update the GOT map.
+  MutexGuard locked(JR->TheJIT->lock);
+
+  // We might like to remove the call site from the CallSiteToFunction map, but
+  // we can't do that! Multiple threads could be stuck, waiting to acquire the
+  // lock above. As soon as the 1st function finishes compiling the function,
+  // the next one will be released, and needs to be able to find the function it
+  // needs to call.
+
+  // FIXME: We could rewrite all references to this stub if we knew them.
+
+  // What we will do is set the compiled function address to map to the
+  // same GOT entry as the stub so that later clients may update the GOT
+  // if they see it still using the stub address.
+  // Note: this is done so the Resolver doesn't have to manage GOT memory
+  // Do this without allocating map space if the target isn't using a GOT
+  if(JR->revGOTMap.find(Stub) != JR->revGOTMap.end())
+    JR->revGOTMap[Result] = JR->revGOTMap[Stub];
+
+  return Result;
+}
+
+//===----------------------------------------------------------------------===//
+// JITEmitter code.
+//
+
+static GlobalObject *getSimpleAliasee(Constant *C) {
+  C = C->stripPointerCasts();
+  return dyn_cast<GlobalObject>(C);
+}
+
+void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
+                                     bool MayNeedFarStub) {
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
+    return TheJIT->getOrEmitGlobalVariable(GV);
+
+  if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
+    // We can only handle simple cases.
+    if (GlobalValue *GV = getSimpleAliasee(GA->getAliasee()))
+      return TheJIT->getPointerToGlobal(GV);
+    return nullptr;
+  }
+
+  // If we have already compiled the function, return a pointer to its body.
+  Function *F = cast<Function>(V);
+
+  void *FnStub = Resolver.getLazyFunctionStubIfAvailable(F);
+  if (FnStub) {
+    // Return the function stub if it's already created.  We do this first so
+    // that we're returning the same address for the function as any previous
+    // call.  TODO: Yes, this is wrong. The lazy stub isn't guaranteed to be
+    // close enough to call.
+    return FnStub;
+  }
+
+  // If we know the target can handle arbitrary-distance calls, try to
+  // return a direct pointer.
+  if (!MayNeedFarStub) {
+    // If we have code, go ahead and return that.
+    void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
+    if (ResultPtr) return ResultPtr;
+
+    // If this is an external function pointer, we can force the JIT to
+    // 'compile' it, which really just adds it to the map.
+    if (isNonGhostDeclaration(F) || F->hasAvailableExternallyLinkage())
+      return TheJIT->getPointerToFunction(F);
+  }
+
+  // Otherwise, we may need a to emit a stub, and, conservatively, we always do
+  // so.  Note that it's possible to return null from getLazyFunctionStub in the
+  // case of a weak extern that fails to resolve.
+  return Resolver.getLazyFunctionStub(F);
+}
+
+void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference) {
+  // Make sure GV is emitted first, and create a stub containing the fully
+  // resolved address.
+  void *GVAddress = getPointerToGlobal(V, Reference, false);
+  void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
+  return StubAddr;
+}
+
+void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
+  if (DL.isUnknown()) return;
+  if (!BeforePrintingInsn) return;
+
+  const LLVMContext &Context = EmissionDetails.MF->getFunction()->getContext();
+
+  if (DL.getScope(Context) != nullptr && PrevDL != DL) {
+    JITEvent_EmittedFunctionDetails::LineStart NextLine;
+    NextLine.Address = getCurrentPCValue();
+    NextLine.Loc = DL;
+    EmissionDetails.LineStarts.push_back(NextLine);
+  }
+
+  PrevDL = DL;
+}
+
+static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
+                                           const DataLayout *TD) {
+  const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
+  if (Constants.empty()) return 0;
+
+  unsigned Size = 0;
+  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
+    MachineConstantPoolEntry CPE = Constants[i];
+    unsigned AlignMask = CPE.getAlignment() - 1;
+    Size = (Size + AlignMask) & ~AlignMask;
+    Type *Ty = CPE.getType();
+    Size += TD->getTypeAllocSize(Ty);
+  }
+  return Size;
+}
+
+void JITEmitter::startFunction(MachineFunction &F) {
+  DEBUG(dbgs() << "JIT: Starting CodeGen of Function "
+        << F.getName() << "\n");
+
+  uintptr_t ActualSize = 0;
+  // Set the memory writable, if it's not already
+  MemMgr->setMemoryWritable();
+
+  if (SizeEstimate > 0) {
+    // SizeEstimate will be non-zero on reallocation attempts.
+    ActualSize = SizeEstimate;
+  }
+
+  BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
+                                                         ActualSize);
+  BufferEnd = BufferBegin+ActualSize;
+  EmittedFunctions[F.getFunction()].FunctionBody = BufferBegin;
+
+  // Ensure the constant pool/jump table info is at least 4-byte aligned.
+  emitAlignment(16);
+
+  emitConstantPool(F.getConstantPool());
+  if (MachineJumpTableInfo *MJTI = F.getJumpTableInfo())
+    initJumpTableInfo(MJTI);
+
+  // About to start emitting the machine code for the function.
+  emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
+  TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
+  EmittedFunctions[F.getFunction()].Code = CurBufferPtr;
+
+  MBBLocations.clear();
+
+  EmissionDetails.MF = &F;
+  EmissionDetails.LineStarts.clear();
+}
+
+bool JITEmitter::finishFunction(MachineFunction &F) {
+  if (CurBufferPtr == BufferEnd) {
+    // We must call endFunctionBody before retrying, because
+    // deallocateMemForFunction requires it.
+    MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
+    retryWithMoreMemory(F);
+    return true;
+  }
+
+  if (MachineJumpTableInfo *MJTI = F.getJumpTableInfo())
+    emitJumpTableInfo(MJTI);
+
+  // FnStart is the start of the text, not the start of the constant pool and
+  // other per-function data.
+  uint8_t *FnStart =
+    (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
+
+  // FnEnd is the end of the function's machine code.
+  uint8_t *FnEnd = CurBufferPtr;
+
+  if (!Relocations.empty()) {
+    CurFn = F.getFunction();
+    NumRelos += Relocations.size();
+
+    // Resolve the relocations to concrete pointers.
+    for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
+      MachineRelocation &MR = Relocations[i];
+      void *ResultPtr = nullptr;
+      if (!MR.letTargetResolve()) {
+        if (MR.isExternalSymbol()) {
+          ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
+                                                        false);
+          DEBUG(dbgs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
+                       << ResultPtr << "]\n");
+
+          // If the target REALLY wants a stub for this function, emit it now.
+          if (MR.mayNeedFarStub()) {
+            ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
+          }
+        } else if (MR.isGlobalValue()) {
+          ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
+                                         BufferBegin+MR.getMachineCodeOffset(),
+                                         MR.mayNeedFarStub());
+        } else if (MR.isIndirectSymbol()) {
+          ResultPtr = getPointerToGVIndirectSym(
+              MR.getGlobalValue(), BufferBegin+MR.getMachineCodeOffset());
+        } else if (MR.isBasicBlock()) {
+          ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
+        } else if (MR.isConstantPoolIndex()) {
+          ResultPtr =
+            (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
+        } else {
+          assert(MR.isJumpTableIndex());
+          ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
+        }
+
+        MR.setResultPointer(ResultPtr);
+      }
+
+      // if we are managing the GOT and the relocation wants an index,
+      // give it one
+      if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
+        unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
+        MR.setGOTIndex(idx);
+        if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
+          DEBUG(dbgs() << "JIT: GOT was out of date for " << ResultPtr
+                       << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
+                       << "\n");
+          ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
+        }
+      }
+    }
+
+    CurFn = nullptr;
+    TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
+                                  Relocations.size(), MemMgr->getGOTBase());
+  }
+
+  // Update the GOT entry for F to point to the new code.
+  if (MemMgr->isManagingGOT()) {
+    unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
+    if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
+      DEBUG(dbgs() << "JIT: GOT was out of date for " << (void*)BufferBegin
+                   << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
+                   << "\n");
+      ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
+    }
+  }
+
+  // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
+  // global variables that were referenced in the relocations.
+  MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
+
+  if (CurBufferPtr == BufferEnd) {
+    retryWithMoreMemory(F);
+    return true;
+  } else {
+    // Now that we've succeeded in emitting the function, reset the
+    // SizeEstimate back down to zero.
+    SizeEstimate = 0;
+  }
+
+  BufferBegin = CurBufferPtr = nullptr;
+  NumBytes += FnEnd-FnStart;
+
+  // Invalidate the icache if necessary.
+  sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
+
+  TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
+                                EmissionDetails);
+
+  // Reset the previous debug location.
+  PrevDL = DebugLoc();
+
+  DEBUG(dbgs() << "JIT: Finished CodeGen of [" << (void*)FnStart
+        << "] Function: " << F.getName()
+        << ": " << (FnEnd-FnStart) << " bytes of text, "
+        << Relocations.size() << " relocations\n");
+
+  Relocations.clear();
+  ConstPoolAddresses.clear();
+
+  // Mark code region readable and executable if it's not so already.
+  MemMgr->setMemoryExecutable();
+
+  DEBUG({
+        dbgs() << "JIT: Binary code:\n";
+        uint8_t* q = FnStart;
+        for (int i = 0; q < FnEnd; q += 4, ++i) {
+          if (i == 4)
+            i = 0;
+          if (i == 0)
+            dbgs() << "JIT: " << (long)(q - FnStart) << ": ";
+          bool Done = false;
+          for (int j = 3; j >= 0; --j) {
+            if (q + j >= FnEnd)
+              Done = true;
+            else
+              dbgs() << (unsigned short)q[j];
+          }
+          if (Done)
+            break;
+          dbgs() << ' ';
+          if (i == 3)
+            dbgs() << '\n';
+        }
+        dbgs()<< '\n';
+    });
+
+  if (MMI)
+    MMI->EndFunction();
+
+  return false;
+}
+
+void JITEmitter::retryWithMoreMemory(MachineFunction &F) {
+  DEBUG(dbgs() << "JIT: Ran out of space for native code.  Reattempting.\n");
+  Relocations.clear();  // Clear the old relocations or we'll reapply them.
+  ConstPoolAddresses.clear();
+  ++NumRetries;
+  deallocateMemForFunction(F.getFunction());
+  // Try again with at least twice as much free space.
+  SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin));
+
+  for (MachineFunction::iterator MBB = F.begin(), E = F.end(); MBB != E; ++MBB){
+    if (MBB->hasAddressTaken())
+      TheJIT->clearPointerToBasicBlock(MBB->getBasicBlock());
+  }
+}
+
+/// deallocateMemForFunction - Deallocate all memory for the specified
+/// function body.  Also drop any references the function has to stubs.
+/// May be called while the Function is being destroyed inside ~Value().
+void JITEmitter::deallocateMemForFunction(const Function *F) {
+  ValueMap<const Function *, EmittedCode, EmittedFunctionConfig>::iterator
+    Emitted = EmittedFunctions.find(F);
+  if (Emitted != EmittedFunctions.end()) {
+    MemMgr->deallocateFunctionBody(Emitted->second.FunctionBody);
+    TheJIT->NotifyFreeingMachineCode(Emitted->second.Code);
+
+    EmittedFunctions.erase(Emitted);
+  }
+}
+
+
+void *JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
+  if (BufferBegin)
+    return JITCodeEmitter::allocateSpace(Size, Alignment);
+
+  // create a new memory block if there is no active one.
+  // care must be taken so that BufferBegin is invalidated when a
+  // block is trimmed
+  BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
+  BufferEnd = BufferBegin+Size;
+  return CurBufferPtr;
+}
+
+void *JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
+  // Delegate this call through the memory manager.
+  return MemMgr->allocateGlobal(Size, Alignment);
+}
+
+void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
+  if (TheJIT->getJITInfo().hasCustomConstantPool())
+    return;
+
+  const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
+  if (Constants.empty()) return;
+
+  unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getDataLayout());
+  unsigned Align = MCP->getConstantPoolAlignment();
+  ConstantPoolBase = allocateSpace(Size, Align);
+  ConstantPool = MCP;
+
+  if (!ConstantPoolBase) return;  // Buffer overflow.
+
+  DEBUG(dbgs() << "JIT: Emitted constant pool at [" << ConstantPoolBase
+               << "] (size: " << Size << ", alignment: " << Align << ")\n");
+
+  // Initialize the memory for all of the constant pool entries.
+  unsigned Offset = 0;
+  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
+    MachineConstantPoolEntry CPE = Constants[i];
+    unsigned AlignMask = CPE.getAlignment() - 1;
+    Offset = (Offset + AlignMask) & ~AlignMask;
+
+    uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
+    ConstPoolAddresses.push_back(CAddr);
+    if (CPE.isMachineConstantPoolEntry()) {
+      // FIXME: add support to lower machine constant pool values into bytes!
+      report_fatal_error("Initialize memory with machine specific constant pool"
+                        "entry has not been implemented!");
+    }
+    TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
+    DEBUG(dbgs() << "JIT:   CP" << i << " at [0x";
+          dbgs().write_hex(CAddr) << "]\n");
+
+    Type *Ty = CPE.Val.ConstVal->getType();
+    Offset += TheJIT->getDataLayout()->getTypeAllocSize(Ty);
+  }
+}
+
+void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
+  if (TheJIT->getJITInfo().hasCustomJumpTables())
+    return;
+  if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline)
+    return;
+
+  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+  if (JT.empty()) return;
+
+  unsigned NumEntries = 0;
+  for (unsigned i = 0, e = JT.size(); i != e; ++i)
+    NumEntries += JT[i].MBBs.size();
+
+  unsigned EntrySize = MJTI->getEntrySize(*TheJIT->getDataLayout());
+
+  // Just allocate space for all the jump tables now.  We will fix up the actual
+  // MBB entries in the tables after we emit the code for each block, since then
+  // we will know the final locations of the MBBs in memory.
+  JumpTable = MJTI;
+  JumpTableBase = allocateSpace(NumEntries * EntrySize,
+                             MJTI->getEntryAlignment(*TheJIT->getDataLayout()));
+}
+
+void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
+  if (TheJIT->getJITInfo().hasCustomJumpTables())
+    return;
+
+  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+  if (JT.empty() || !JumpTableBase) return;
+
+
+  switch (MJTI->getEntryKind()) {
+  case MachineJumpTableInfo::EK_Inline:
+    return;
+  case MachineJumpTableInfo::EK_BlockAddress: {
+    // EK_BlockAddress - Each entry is a plain address of block, e.g.:
+    //     .word LBB123
+    assert(MJTI->getEntrySize(*TheJIT->getDataLayout()) == sizeof(void*) &&
+           "Cross JIT'ing?");
+
+    // For each jump table, map each target in the jump table to the address of
+    // an emitted MachineBasicBlock.
+    intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
+
+    for (unsigned i = 0, e = JT.size(); i != e; ++i) {
+      const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
+      // Store the address of the basic block for this jump table slot in the
+      // memory we allocated for the jump table in 'initJumpTableInfo'
+      for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
+        *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
+    }
+    break;
+  }
+
+  case MachineJumpTableInfo::EK_Custom32:
+  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
+  case MachineJumpTableInfo::EK_LabelDifference32: {
+    assert(MJTI->getEntrySize(*TheJIT->getDataLayout()) == 4&&"Cross JIT'ing?");
+    // For each jump table, place the offset from the beginning of the table
+    // to the target address.
+    int *SlotPtr = (int*)JumpTableBase;
+
+    for (unsigned i = 0, e = JT.size(); i != e; ++i) {
+      const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
+      // Store the offset of the basic block for this jump table slot in the
+      // memory we allocated for the jump table in 'initJumpTableInfo'
+      uintptr_t Base = (uintptr_t)SlotPtr;
+      for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
+        uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
+        /// FIXME: USe EntryKind instead of magic "getPICJumpTableEntry" hook.
+        *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
+      }
+    }
+    break;
+  }
+  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
+    llvm_unreachable(
+           "JT Info emission not implemented for GPRel64BlockAddress yet.");
+  }
+}
+
+void JITEmitter::startGVStub(const GlobalValue* GV,
+                             unsigned StubSize, unsigned Alignment) {
+  SavedBufferBegin = BufferBegin;
+  SavedBufferEnd = BufferEnd;
+  SavedCurBufferPtr = CurBufferPtr;
+
+  BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
+  BufferEnd = BufferBegin+StubSize+1;
+}
+
+void JITEmitter::startGVStub(void *Buffer, unsigned StubSize) {
+  SavedBufferBegin = BufferBegin;
+  SavedBufferEnd = BufferEnd;
+  SavedCurBufferPtr = CurBufferPtr;
+
+  BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
+  BufferEnd = BufferBegin+StubSize+1;
+}
+
+void JITEmitter::finishGVStub() {
+  assert(CurBufferPtr != BufferEnd && "Stub overflowed allocated space.");
+  NumBytes += getCurrentPCOffset();
+  BufferBegin = SavedBufferBegin;
+  BufferEnd = SavedBufferEnd;
+  CurBufferPtr = SavedCurBufferPtr;
+}
+
+void *JITEmitter::allocIndirectGV(const GlobalValue *GV,
+                                  const uint8_t *Buffer, size_t Size,
+                                  unsigned Alignment) {
+  uint8_t *IndGV = MemMgr->allocateStub(GV, Size, Alignment);
+  memcpy(IndGV, Buffer, Size);
+  return IndGV;
+}
+
+// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
+// in the constant pool that was last emitted with the 'emitConstantPool'
+// method.
+//
+uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
+  assert(ConstantNum < ConstantPool->getConstants().size() &&
+         "Invalid ConstantPoolIndex!");
+  return ConstPoolAddresses[ConstantNum];
+}
+
+// getJumpTableEntryAddress - Return the address of the JumpTable with index
+// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
+//
+uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
+  const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
+  assert(Index < JT.size() && "Invalid jump table index!");
+
+  unsigned EntrySize = JumpTable->getEntrySize(*TheJIT->getDataLayout());
+
+  unsigned Offset = 0;
+  for (unsigned i = 0; i < Index; ++i)
+    Offset += JT[i].MBBs.size();
+
+   Offset *= EntrySize;
+
+  return (uintptr_t)((char *)JumpTableBase + Offset);
+}
+
+void JITEmitter::EmittedFunctionConfig::onDelete(
+  JITEmitter *Emitter, const Function *F) {
+  Emitter->deallocateMemForFunction(F);
+}
+void JITEmitter::EmittedFunctionConfig::onRAUW(
+  JITEmitter *, const Function*, const Function*) {
+  llvm_unreachable("The JIT doesn't know how to handle a"
+                   " RAUW on a value it has emitted.");
+}
+
+
+//===----------------------------------------------------------------------===//
+//  Public interface to this file
+//===----------------------------------------------------------------------===//
+
+JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM,
+                                   TargetMachine &tm) {
+  return new JITEmitter(jit, JMM, tm);
+}
+
+// getPointerToFunctionOrStub - If the specified function has been
+// code-gen'd, return a pointer to the function.  If not, compile it, or use
+// a stub to implement lazy compilation if available.
+//
+void *JIT::getPointerToFunctionOrStub(Function *F) {
+  // If we have already code generated the function, just return the address.
+  if (void *Addr = getPointerToGlobalIfAvailable(F))
+    return Addr;
+
+  // Get a stub if the target supports it.
+  JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
+  return JE->getJITResolver().getLazyFunctionStub(F);
+}
+
+void JIT::updateFunctionStubUnlocked(Function *F) {
+  // Get the empty stub we generated earlier.
+  JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
+  void *Stub = JE->getJITResolver().getLazyFunctionStub(F);
+  void *Addr = getPointerToGlobalIfAvailable(F);
+  assert(Addr != Stub && "Function must have non-stub address to be updated.");
+
+  // Tell the target jit info to rewrite the stub at the specified address,
+  // rather than creating a new one.
+  TargetJITInfo::StubLayout layout = getJITInfo().getStubLayout();
+  JE->startGVStub(Stub, layout.Size);
+  getJITInfo().emitFunctionStub(F, Addr, *getCodeEmitter());
+  JE->finishGVStub();
+}
+
+/// freeMachineCodeForFunction - release machine code memory for given Function.
+///
+void JIT::freeMachineCodeForFunction(Function *F) {
+  // Delete translation for this from the ExecutionEngine, so it will get
+  // retranslated next time it is used.
+  updateGlobalMapping(F, nullptr);
+
+  // Free the actual memory for the function body and related stuff.
+  static_cast<JITEmitter*>(JCE)->deallocateMemForFunction(F);
+}
diff --git a/llvm/lib/ExecutionEngine/MCJIT/JITMemoryManager.cpp b/llvm/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
index 584b93f8150..584b93f8150 100644
--- a/llvm/lib/ExecutionEngine/MCJIT/JITMemoryManager.cpp
+++ b/llvm/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
diff --git a/llvm/lib/ExecutionEngine/JIT/LLVMBuild.txt b/llvm/lib/ExecutionEngine/JIT/LLVMBuild.txt
new file mode 100644
index 00000000000..dd22f1b464a
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JIT/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/ExecutionEngine/JIT/LLVMBuild.txt ------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = JIT
+parent = ExecutionEngine
+required_libraries = CodeGen Core ExecutionEngine Support
diff --git a/llvm/lib/ExecutionEngine/JIT/Makefile b/llvm/lib/ExecutionEngine/JIT/Makefile
new file mode 100644
index 00000000000..aafa3d9d420
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JIT/Makefile
@@ -0,0 +1,38 @@
+##===- lib/ExecutionEngine/JIT/Makefile --------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../..
+LIBRARYNAME = LLVMJIT
+
+# Get the $(ARCH) setting
+include $(LEVEL)/Makefile.config
+
+# Enable the X86 JIT if compiling on X86
+ifeq ($(ARCH), x86)
+  ENABLE_X86_JIT = 1
+endif
+
+# This flag can also be used on the command line to force inclusion
+# of the X86 JIT on non-X86 hosts
+ifdef ENABLE_X86_JIT
+  CPPFLAGS += -DENABLE_X86_JIT
+endif
+
+# Enable the Sparc JIT if compiling on Sparc
+ifeq ($(ARCH), Sparc)
+  ENABLE_SPARC_JIT = 1
+endif
+
+# This flag can also be used on the command line to force inclusion
+# of the Sparc JIT on non-Sparc hosts
+ifdef ENABLE_SPARC_JIT
+  CPPFLAGS += -DENABLE_SPARC_JIT
+endif
+
+include $(LEVEL)/Makefile.common
diff --git a/llvm/lib/ExecutionEngine/LLVMBuild.txt b/llvm/lib/ExecutionEngine/LLVMBuild.txt
index ecae078ec7d..6dc75af2ec9 100644
--- a/llvm/lib/ExecutionEngine/LLVMBuild.txt
+++ b/llvm/lib/ExecutionEngine/LLVMBuild.txt
@@ -16,7 +16,7 @@
 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = Interpreter MCJIT RuntimeDyld IntelJITEvents OProfileJIT
+subdirectories = Interpreter JIT MCJIT RuntimeDyld IntelJITEvents OProfileJIT
 
 [component_0]
 type = Library
diff --git a/llvm/lib/ExecutionEngine/MCJIT/CMakeLists.txt b/llvm/lib/ExecutionEngine/MCJIT/CMakeLists.txt
index 0f42c31060b..088635a0e99 100644
--- a/llvm/lib/ExecutionEngine/MCJIT/CMakeLists.txt
+++ b/llvm/lib/ExecutionEngine/MCJIT/CMakeLists.txt
@@ -1,5 +1,4 @@
 add_llvm_library(LLVMMCJIT
-  JITMemoryManager.cpp
   MCJIT.cpp
   SectionMemoryManager.cpp
   )
diff --git a/llvm/lib/ExecutionEngine/MCJIT/MCJIT.cpp b/llvm/lib/ExecutionEngine/MCJIT/MCJIT.cpp
index 5f1fac7eff1..53630d5a5e8 100644
--- a/llvm/lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ b/llvm/lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -247,6 +247,10 @@ void MCJIT::finalizeModule(Module *M) {
   finalizeLoadedModules();
 }
 
+void *MCJIT::getPointerToBasicBlock(BasicBlock *BB) {
+  report_fatal_error("not yet implemented");
+}
+
 uint64_t MCJIT::getExistingSymbolAddress(const std::string &Name) {
   Mangler Mang(TM->getSubtargetImpl()->getDataLayout());
   SmallString<128> FullName;
@@ -368,6 +372,14 @@ void *MCJIT::getPointerToFunction(Function *F) {
   return (void*)Dyld.getSymbolLoadAddress(Name);
 }
 
+void *MCJIT::recompileAndRelinkFunction(Function *F) {
+  report_fatal_error("not yet implemented");
+}
+
+void MCJIT::freeMachineCodeForFunction(Function *F) {
+  report_fatal_error("not yet implemented");
+}
+
 void MCJIT::runStaticConstructorsDestructorsInModulePtrSet(
     bool isDtors, ModulePtrSet::iterator I, ModulePtrSet::iterator E) {
   for (; I != E; ++I) {
@@ -537,7 +549,8 @@ void MCJIT::UnregisterJITEventListener(JITEventListener *L) {
   if (!L)
     return;
   MutexGuard locked(lock);
-  auto I = std::find(EventListeners.rbegin(), EventListeners.rend(), L);
+  SmallVector<JITEventListener*, 2>::reverse_iterator I=
+      std::find(EventListeners.rbegin(), EventListeners.rend(), L);
   if (I != EventListeners.rend()) {
     std::swap(*I, EventListeners.back());
     EventListeners.pop_back();
@@ -553,8 +566,7 @@ void MCJIT::NotifyObjectEmitted(const ObjectImage& Obj) {
 void MCJIT::NotifyFreeingObject(const ObjectImage& Obj) {
   MutexGuard locked(lock);
   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
-    JITEventListener *L = EventListeners[I];
-    L->NotifyFreeingObject(Obj);
+    EventListeners[I]->NotifyFreeingObject(Obj);
   }
 }
 
diff --git a/llvm/lib/ExecutionEngine/MCJIT/MCJIT.h b/llvm/lib/ExecutionEngine/MCJIT/MCJIT.h
index 247de7c90b8..83e3321db92 100644
--- a/llvm/lib/ExecutionEngine/MCJIT/MCJIT.h
+++ b/llvm/lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -211,7 +211,7 @@ class MCJIT : public ExecutionEngine {
   MCContext *Ctx;
   LinkingMemoryManager MemMgr;
   RuntimeDyld Dyld;
-  std::vector<JITEventListener*> EventListeners;
+  SmallVector<JITEventListener*, 2> EventListeners;
 
   OwningModuleContainer OwnedModules;
 
@@ -275,8 +275,14 @@ public:
   /// \param isDtors - Run the destructors instead of constructors.
   void runStaticConstructorsDestructors(bool isDtors) override;
 
+  void *getPointerToBasicBlock(BasicBlock *BB) override;
+
   void *getPointerToFunction(Function *F) override;
 
+  void *recompileAndRelinkFunction(Function *F) override;
+
+  void freeMachineCodeForFunction(Function *F) override;
+
   GenericValue runFunction(Function *F,
                            const std::vector<GenericValue> &ArgValues) override;
 
diff --git a/llvm/lib/ExecutionEngine/Makefile b/llvm/lib/ExecutionEngine/Makefile
index cf714324e3b..c26e0ada5bc 100644
--- a/llvm/lib/ExecutionEngine/Makefile
+++ b/llvm/lib/ExecutionEngine/Makefile
@@ -11,7 +11,7 @@ LIBRARYNAME = LLVMExecutionEngine
 
 include $(LEVEL)/Makefile.config
 
-PARALLEL_DIRS = Interpreter MCJIT RuntimeDyld
+PARALLEL_DIRS = Interpreter JIT MCJIT RuntimeDyld
 
 ifeq ($(USE_INTEL_JITEVENTS), 1)
 PARALLEL_DIRS += IntelJITEvents
diff --git a/llvm/lib/ExecutionEngine/TargetSelect.cpp b/llvm/lib/ExecutionEngine/TargetSelect.cpp
index e6679cfb7f7..b10d51f6486 100644
--- a/llvm/lib/ExecutionEngine/TargetSelect.cpp
+++ b/llvm/lib/ExecutionEngine/TargetSelect.cpp
@@ -30,7 +30,7 @@ TargetMachine *EngineBuilder::selectTarget() {
 
   // MCJIT can generate code for remote targets, but the old JIT and Interpreter
   // must use the host architecture.
-  if (WhichEngine != EngineKind::Interpreter && M)
+  if (UseMCJIT && WhichEngine != EngineKind::Interpreter && M)
     TT.setTriple(M->getTargetTriple());
 
   return selectTarget(TT, MArch, MCPU, MAttrs);
@@ -89,7 +89,8 @@ TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
   }
 
   // FIXME: non-iOS ARM FastISel is broken with MCJIT.
-  if (TheTriple.getArch() == Triple::arm &&
+  if (UseMCJIT &&
+      TheTriple.getArch() == Triple::arm &&
       !TheTriple.isiOS() &&
       OptLevel == CodeGenOpt::None) {
     OptLevel = CodeGenOpt::Less;