X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FExecutionEngine%2FJIT%2FJITEmitter.cpp;h=2ba1f8695d7c9c195500a1a867edf14bfb189782;hb=7ad7c75048eb32f95eae04847908793e0183802f;hp=2915f4967299d70459eca88f9ff40847527a5a9c;hpb=23e5fcfec4640955fec41dc8348f467adf1a3e56;p=oota-llvm.git

diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
index 2915f496729..2ba1f8695d7 100644
--- a/lib/ExecutionEngine/JIT/JITEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -12,65 +12,71 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "jit"
 #include "JIT.h"
-#include "JITDebugRegisterer.h"
-#include "JITDwarfEmitter.h"
-#include "llvm/ADT/OwningPtr.h"
-#include "llvm/Constants.h"
-#include "llvm/Module.h"
-#include "llvm/DerivedTypes.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/MachineFunction.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/CodeGen/MachineCodeInfo.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Target/TargetJITInfo.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetOptions.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/ValueHandle.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/System/Disassembler.h"
-#include "llvm/System/Memory.h"
 #include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/ValueMap.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");
-static JIT *TheJIT = 0;
 
 
+// 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) {
-      assert(false && "The JIT doesn't know how to handle a"
-             " RAUW on a value it has emitted.");
+      llvm_unreachable("The JIT doesn't know how to handle a"
+                       " RAUW on a value it has emitted.");
     }
   };
 
@@ -82,15 +88,15 @@ namespace {
   class JITResolverState {
   public:
     typedef ValueMap<Function*, void*, NoRAUWValueMapConfig<Function*> >
-      FunctionToStubMapTy;
+      FunctionToLazyStubMapTy;
     typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy;
     typedef ValueMap<Function *, SmallPtrSet<void*, 1>,
                      CallSiteValueMapConfig> FunctionToCallSitesMapTy;
     typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
   private:
-    /// FunctionToStubMap - Keep track of the stub created for a particular
-    /// function so that we can reuse them if necessary.
-    FunctionToStubMapTy FunctionToStubMap;
+    /// 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.
@@ -101,26 +107,32 @@ namespace {
     /// 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() : FunctionToStubMap(this),
-                         FunctionToCallSitesMap(this) {}
+    JITResolverState(JIT *jit) : FunctionToLazyStubMap(this),
+                                 FunctionToCallSitesMap(this) {
+#ifndef NDEBUG
+      TheJIT = jit;
+#endif
+    }
 
-    FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) {
-      assert(locked.holds(TheJIT->lock));
-      return FunctionToStubMap;
+    FunctionToLazyStubMapTy& getFunctionToLazyStubMap() {
+      return FunctionToLazyStubMap;
     }
 
-    GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) {
-      assert(locked.holds(TheJIT->lock));
+    GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap() {
       return GlobalToIndirectSymMap;
     }
 
-    pair<void *, Function *> LookupFunctionFromCallSite(
-        const MutexGuard &locked, void *CallSite) const {
-      assert(locked.holds(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 *> 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() &&
@@ -129,9 +141,7 @@ namespace {
       return *I;
     }
 
-    void AddCallSite(const MutexGuard &locked, void *CallSite, Function *F) {
-      assert(locked.holds(TheJIT->lock));
-
+    void AddCallSite(void *CallSite, Function *F) {
       bool Inserted = CallSiteToFunctionMap.insert(
           std::make_pair(CallSite, F)).second;
       (void)Inserted;
@@ -139,63 +149,18 @@ namespace {
       FunctionToCallSitesMap[F].insert(CallSite);
     }
 
-    // Returns the Function of the stub if a stub was erased, or NULL if there
-    // was no stub.  This function uses the call-site->function map to find a
-    // relevant function, but asserts that only stubs and not other call sites
-    // will be passed in.
-    Function *EraseStub(const MutexGuard &locked, void *Stub) {
-      CallSiteToFunctionMapTy::iterator C2F_I =
-        CallSiteToFunctionMap.find(Stub);
-      if (C2F_I == CallSiteToFunctionMap.end()) {
-        // Not a stub.
-        return NULL;
-      }
-
-      Function *const F = C2F_I->second;
-#ifndef NDEBUG
-      void *RealStub = FunctionToStubMap.lookup(F);
-      assert(RealStub == Stub &&
-             "Call-site that wasn't a stub pass in to EraseStub");
-#endif
-      FunctionToStubMap.erase(F);
-      CallSiteToFunctionMap.erase(C2F_I);
-
-      // Remove the stub from the function->call-sites map, and remove the whole
-      // entry from the map if that was the last call site.
-      FunctionToCallSitesMapTy::iterator F2C_I = FunctionToCallSitesMap.find(F);
-      assert(F2C_I != FunctionToCallSitesMap.end() &&
-             "FunctionToCallSitesMap broken");
-      bool Erased = F2C_I->second.erase(Stub);
-      (void)Erased;
-      assert(Erased && "FunctionToCallSitesMap broken");
-      if (F2C_I->second.empty())
-        FunctionToCallSitesMap.erase(F2C_I);
-
-      return F;
-    }
+    void EraseAllCallSitesForPrelocked(Function *F);
 
-    void EraseAllCallSites(const MutexGuard &locked, Function *F) {
-      assert(locked.holds(TheJIT->lock));
-      EraseAllCallSitesPrelocked(F);
-    }
-    void EraseAllCallSitesPrelocked(Function *F) {
-      FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F);
-      if (F2C == FunctionToCallSitesMap.end())
-        return;
-      for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(),
-             E = F2C->second.end(); I != E; ++I) {
-        bool Erased = CallSiteToFunctionMap.erase(*I);
-        (void)Erased;
-        assert(Erased && "Missing call site->function mapping");
-      }
-      FunctionToCallSitesMap.erase(F2C);
-    }
+    // 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::FunctionToStubMapTy FunctionToStubMapTy;
+    typedef JITResolverState::FunctionToLazyStubMapTy FunctionToLazyStubMapTy;
     typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy;
     typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
 
@@ -205,36 +170,37 @@ namespace {
 
     JITResolverState state;
 
-    /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
-    /// external functions.
+    /// 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;
 
-    static JITResolver *TheJITResolver;
-  public:
-    explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
-      TheJIT = &jit;
+    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);
-      assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
-      TheJITResolver = this;
-    }
-    
-    ~JITResolver() {
-      TheJITResolver = 0;
     }
 
-    /// getFunctionStubIfAvailable - This returns a pointer to a function stub
-    /// if it has already been created.
-    void *getFunctionStubIfAvailable(Function *F);
+    ~JITResolver();
 
-    /// getFunctionStub - This returns a pointer to a function stub, creating
-    /// one on demand as needed.  If empty is true, create a function stub
-    /// pointing at address 0, to be filled in later.
-    void *getFunctionStub(Function *F);
+    /// 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.
@@ -244,21 +210,6 @@ namespace {
     /// specified GV address.
     void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
 
-    /// AddCallbackAtLocation - If the target is capable of rewriting an
-    /// instruction without the use of a stub, record the location of the use so
-    /// we know which function is being used at the location.
-    void *AddCallbackAtLocation(Function *F, void *Location) {
-      MutexGuard locked(TheJIT->lock);
-      /// Get the target-specific JIT resolver function.
-      state.AddCallSite(locked, Location, F);
-      return (void*)(intptr_t)LazyResolverFn;
-    }
-    
-    void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
-                           SmallVectorImpl<void*> &Ptrs);
-    
-    GlobalValue *invalidateStub(void *Stub);
-
     /// 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.
@@ -269,53 +220,315 @@ namespace {
     /// been compiled, this function compiles it first.
     static void *JITCompilerFn(void *Stub);
   };
-}
 
-JITResolver *JITResolver::TheJITResolver = 0;
+  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->EraseAllCallSitesPrelocked(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);
 }
 
-/// getFunctionStubIfAvailable - This returns a pointer to a function stub
+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::getFunctionStubIfAvailable(Function *F) {
+void *JITResolver::getLazyFunctionStubIfAvailable(Function *F) {
   MutexGuard locked(TheJIT->lock);
 
   // If we already have a stub for this function, recycle it.
-  return state.getFunctionToStubMap(locked).lookup(F);
+  return state.getFunctionToLazyStubMap().lookup(F);
 }
 
 /// getFunctionStub - This returns a pointer to a function stub, creating
 /// one on demand as needed.
-void *JITResolver::getFunctionStub(Function *F) {
+void *JITResolver::getLazyFunctionStub(Function *F) {
   MutexGuard locked(TheJIT->lock);
 
-  // If we already have a stub for this function, recycle it.
-  void *&Stub = state.getFunctionToStubMap(locked)[F];
+  // 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 unless we are JIT'ing non-lazily, in which
-  // case we must resolve the symbol now.
-  void *Actual = TheJIT->isLazyCompilationDisabled()
-    ? (void *)0 : (void *)(intptr_t)LazyResolverFn;
-  
+  // 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 (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
+  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 dlsym
-    // stubs are enabled, not being able to resolve the address is not
-    // meaningful.
-    if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
+    // 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,
-                                               *TheJIT->getCodeEmitter());
+  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
@@ -324,19 +537,25 @@ void *JITResolver::getFunctionStub(Function *F) {
     TheJIT->updateGlobalMapping(F, Stub);
   }
 
-  DEBUG(errs() << "JIT: Stub emitted at [" << Stub << "] for function '"
+  DEBUG(dbgs() << "JIT: Lazy stub emitted at [" << Stub << "] for function '"
         << F->getName() << "'\n");
 
-  // Finally, keep track of the stub-to-Function mapping so that the
-  // JITCompilerFn knows which function to compile!
-  state.AddCallSite(locked, Stub, F);
-
-  // 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.
-  if (!Actual && TheJIT->isLazyCompilationDisabled())
-    if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
-      TheJIT->addPendingFunction(F);
+  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;
 }
@@ -347,14 +566,14 @@ 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(locked)[GV];
+  void *&IndirectSym = state.getGlobalToIndirectSymMap()[GV];
   if (IndirectSym) return IndirectSym;
 
   // Otherwise, codegen a new indirect symbol.
   IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
-                                                     *TheJIT->getCodeEmitter());
+                                                                JE);
 
-  DEBUG(errs() << "JIT: Indirect symbol emitted at [" << IndirectSym 
+  DEBUG(dbgs() << "JIT: Indirect symbol emitted at [" << IndirectSym
         << "] for GV '" << GV->getName() << "'\n");
 
   return IndirectSym;
@@ -367,10 +586,12 @@ void *JITResolver::getExternalFunctionStub(void *FnAddr) {
   void *&Stub = ExternalFnToStubMap[FnAddr];
   if (Stub) return Stub;
 
-  Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
-                                               *TheJIT->getCodeEmitter());
+  TargetJITInfo::StubLayout SL = TheJIT->getJITInfo().getStubLayout();
+  JE.startGVStub(nullptr, SL.Size, SL.Alignment);
+  Stub = TheJIT->getJITInfo().emitFunctionStub(nullptr, FnAddr, JE);
+  JE.finishGVStub();
 
-  DEBUG(errs() << "JIT: Stub emitted at [" << Stub
+  DEBUG(dbgs() << "JIT: Stub emitted at [" << Stub
                << "] for external function at '" << FnAddr << "'\n");
   return Stub;
 }
@@ -380,111 +601,59 @@ unsigned JITResolver::getGOTIndexForAddr(void* addr) {
   if (!idx) {
     idx = ++nextGOTIndex;
     revGOTMap[addr] = idx;
-    DEBUG(errs() << "JIT: Adding GOT entry " << idx << " for addr ["
+    DEBUG(dbgs() << "JIT: Adding GOT entry " << idx << " for addr ["
                  << addr << "]\n");
   }
   return idx;
 }
 
-void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
-                                    SmallVectorImpl<void*> &Ptrs) {
-  MutexGuard locked(TheJIT->lock);
-  
-  const FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
-  GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
-  
-  for (FunctionToStubMapTy::const_iterator i = FM.begin(), e = FM.end();
-       i != e; ++i){
-    Function *F = i->first;
-    if (F->isDeclaration() && F->hasExternalLinkage()) {
-      GVs.push_back(i->first);
-      Ptrs.push_back(i->second);
-    }
-  }
-  for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
-       i != e; ++i) {
-    GVs.push_back(i->first);
-    Ptrs.push_back(i->second);
-  }
-}
-
-GlobalValue *JITResolver::invalidateStub(void *Stub) {
-  MutexGuard locked(TheJIT->lock);
-
-  GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
-
-  // Look up the cheap way first, to see if it's a function stub we are
-  // invalidating.  If so, remove it from both the forward and reverse maps.
-  if (Function *F = state.EraseStub(locked, Stub)) {
-    return F;
-  }
-
-  // Otherwise, it might be an indirect symbol stub.  Find it and remove it.
-  for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
-       i != e; ++i) {
-    if (i->second != Stub)
-      continue;
-    GlobalValue *GV = i->first;
-    GM.erase(i);
-    return GV;
-  }
-  
-  // Lastly, check to see if it's in the ExternalFnToStubMap.
-  for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
-       e = ExternalFnToStubMap.end(); i != e; ++i) {
-    if (i->second != Stub)
-      continue;
-    ExternalFnToStubMap.erase(i);
-    break;
-  }
-  
-  return 0;
-}
-
 /// 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 = *TheJITResolver;
-  
-  Function* F = 0;
-  void* ActualPtr = 0;
+  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(TheJIT->lock);
+    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.
-    pair<void*, Function*> I =
-      JR.state.LookupFunctionFromCallSite(locked, Stub);
+    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 = TheJIT->getPointerToGlobalIfAvailable(F);
-  
+  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 (TheJIT->isLazyCompilationDisabled()) {
-      llvm_report_error("LLVM JIT requested to do lazy compilation of function '"
+    if (!JR->TheJIT->isCompilingLazily()) {
+      report_fatal_error("LLVM JIT requested to do lazy compilation of"
+                         " function '"
                         + F->getName() + "' when lazy compiles are disabled!");
     }
-  
-    DEBUG(errs() << "JIT: Lazily resolving function '" << F->getName()
+
+    DEBUG(dbgs() << "JIT: Lazily resolving function '" << F->getName()
           << "' In stub ptr = " << Stub << " actual ptr = "
           << ActualPtr << "\n");
+    (void)ActualPtr;
 
-    Result = TheJIT->getPointerToFunction(F);
+    Result = JR->TheJIT->getPointerToFunction(F);
   }
 
   // Reacquire the lock to update the GOT map.
-  MutexGuard locked(TheJIT->lock);
+  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
@@ -499,8 +668,8 @@ void *JITResolver::JITCompilerFn(void *Stub) {
   // 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];
+  if(JR->revGOTMap.find(Stub) != JR->revGOTMap.end())
+    JR->revGOTMap[Result] = JR->revGOTMap[Stub];
 
   return Result;
 }
@@ -508,318 +677,81 @@ void *JITResolver::JITCompilerFn(void *Stub) {
 //===----------------------------------------------------------------------===//
 // JITEmitter code.
 //
-namespace {
-  /// 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;
-
-    /// DE - The dwarf emitter for the jit.
-    OwningPtr<JITDwarfEmitter> DE;
-
-    /// DR - The debug registerer for the jit.
-    OwningPtr<JITDebugRegisterer> DR;
-
-    /// LabelLocations - This vector is a mapping from Label ID's to their 
-    /// address.
-    std::vector<uintptr_t> LabelLocations;
-
-    /// MMI - Machine module info for exception informations
-    MachineModuleInfo* MMI;
-
-    // GVSet - a set to keep track of which globals have been seen
-    SmallPtrSet<const GlobalVariable*, 8> GVSet;
-
-    // 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;
-      void *ExceptionTable;
-      EmittedCode() : FunctionBody(0), ExceptionTable(0) {}
-    };
-    DenseMap<const Function *, EmittedCode> EmittedFunctions;
-
-    // CurFnStubUses - For a given Function, a vector of stubs that it
-    // references.  This facilitates the JIT detecting that a stub is no
-    // longer used, so that it may be deallocated.
-    DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
-    
-    // StubFnRefs - For a given pointer to a stub, a set of Functions which
-    // reference the stub.  When the count of a stub's references drops to zero,
-    // the stub is unused.
-    DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
-    
-    // ExtFnStubs - A map of external function names to stubs which have entries
-    // in the JITResolver's ExternalFnToStubMap.
-    StringMap<void *> ExtFnStubs;
-
-    DebugLocTuple PrevDLT;
-
-  public:
-    JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM)
-        : SizeEstimate(0), Resolver(jit), MMI(0), CurFn(0) {
-      MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
-      if (jit.getJITInfo().needsGOT()) {
-        MemMgr->AllocateGOT();
-        DEBUG(errs() << "JIT is managing a GOT\n");
-      }
-
-      if (DwarfExceptionHandling || JITEmitDebugInfo) {
-        DE.reset(new JITDwarfEmitter(jit));
-      }
-      if (JITEmitDebugInfo) {
-        DR.reset(new JITDebugRegisterer(TM));
-      }
-    }
-    ~JITEmitter() { 
-      delete MemMgr;
-    }
-
-    /// classof - Methods for support type inquiry through isa, cast, and
-    /// dyn_cast:
-    ///
-    static inline bool classof(const JITEmitter*) { return true; }
-    static inline bool classof(const MachineCodeEmitter*) { return true; }
-    
-    JITResolver &getJITResolver() { return Resolver; }
-
-    virtual void startFunction(MachineFunction &F);
-    virtual bool finishFunction(MachineFunction &F);
-    
-    void emitConstantPool(MachineConstantPool *MCP);
-    void initJumpTableInfo(MachineJumpTableInfo *MJTI);
-    void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
-    
-    virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
-                                   unsigned Alignment = 1);
-    virtual void startGVStub(const GlobalValue* GV, void *Buffer,
-                             unsigned StubSize);
-    virtual void* finishGVStub(const GlobalValue *GV);
-
-    /// allocateSpace - Reserves space in the current block if any, or
-    /// allocate a new one of the given size.
-    virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
-
-    /// 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.
-    virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment);
-
-    virtual void addRelocation(const MachineRelocation &MR) {
-      Relocations.push_back(MR);
-    }
-    
-    virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
-      if (MBBLocations.size() <= (unsigned)MBB->getNumber())
-        MBBLocations.resize((MBB->getNumber()+1)*2);
-      MBBLocations[MBB->getNumber()] = getCurrentPCValue();
-      DEBUG(errs() << "JIT: Emitting BB" << MBB->getNumber() << " at ["
-                   << (void*) getCurrentPCValue() << "]\n");
-    }
-
-    virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
-    virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
-
-    virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
-      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);
-
-    /// AddStubToCurrentFunction - Mark the current function being JIT'd as
-    /// using the stub at the specified address. Allows
-    /// deallocateMemForFunction to also remove stubs no longer referenced.
-    void AddStubToCurrentFunction(void *Stub);
-    
-    /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
-    /// MachineRelocations that reference external functions by name.
-    const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
-    
-    virtual void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn);
-
-    virtual void emitLabel(uint64_t LabelID) {
-      if (LabelLocations.size() <= LabelID)
-        LabelLocations.resize((LabelID+1)*2);
-      LabelLocations[LabelID] = getCurrentPCValue();
-    }
-
-    virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
-      assert(LabelLocations.size() > (unsigned)LabelID && 
-             LabelLocations[LabelID] && "Label not emitted!");
-      return LabelLocations[LabelID];
-    }
- 
-    virtual void setModuleInfo(MachineModuleInfo* Info) {
-      MMI = Info;
-      if (DE.get()) DE->setModuleInfo(Info);
-    }
-
-    void setMemoryExecutable() {
-      MemMgr->setMemoryExecutable();
-    }
-    
-    JITMemoryManager *getMemMgr() const { return MemMgr; }
-
-  private:
-    void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
-    void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
-                                    bool NoNeedStub);
-    unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
-    unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
-    unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
-    unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
-  };
+static GlobalObject *getSimpleAliasee(Constant *C) {
+  C = C->stripPointerCasts();
+  return dyn_cast<GlobalObject>(C);
 }
 
 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
-                                     bool DoesntNeedStub) {
+                                     bool MayNeedFarStub) {
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
     return TheJIT->getOrEmitGlobalVariable(GV);
 
-  if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
-    return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
+  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 *ResultPtr;
-  if (!DoesntNeedStub) {
-    // Return the function stub if it's already created.
-    ResultPtr = Resolver.getFunctionStubIfAvailable(F);
-    if (ResultPtr)
-      AddStubToCurrentFunction(ResultPtr);
-  } else {
-    ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
+
+  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 (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.  In dlsym mode, 
-  // external functions are forced through a stub, regardless of reloc type.
-  if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
-      DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
-    return TheJIT->getPointerToFunction(F);
-
-  // Okay, the function has not been compiled yet, if the target callback
-  // mechanism is capable of rewriting the instruction directly, prefer to do
-  // that instead of emitting a stub.  This uses the lazy resolver, so is not
-  // legal if lazy compilation is disabled.
-  if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
-    return Resolver.AddCallbackAtLocation(F, Reference);
-
-  // Otherwise, we have to emit a stub.
-  void *StubAddr = Resolver.getFunctionStub(F);
-
-  // Add the stub to the current function's list of referenced stubs, so we can
-  // deallocate them if the current function is ever freed.  It's possible to
-  // return null from getFunctionStub in the case of a weak extern that fails
-  // to resolve.
-  if (StubAddr)
-    AddStubToCurrentFunction(StubAddr);
 
-  return StubAddr;
+  // 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,
-                                            bool NoNeedStub) {
+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, true);
+  void *GVAddress = getPointerToGlobal(V, Reference, false);
   void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
-  
-  // Add the stub to the current function's list of referenced stubs, so we can
-  // deallocate them if the current function is ever freed.
-  AddStubToCurrentFunction(StubAddr);
-  
   return StubAddr;
 }
 
-void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
-  assert(CurFn && "Stub added to current function, but current function is 0!");
-
-  SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
-  StubsUsed.push_back(StubAddr);
+void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
+  if (DL.isUnknown()) return;
+  if (!BeforePrintingInsn) return;
 
-  SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
-  FnRefs.insert(CurFn);
-}
+  const LLVMContext &Context = EmissionDetails.MF->getFunction()->getContext();
 
-void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
-  if (!DL.isUnknown()) {
-    DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL);
-
-    if (BeforePrintingInsn) {
-      if (CurDLT.Scope != 0 && PrevDLT != CurDLT) {
-        JITEvent_EmittedFunctionDetails::LineStart NextLine;
-        NextLine.Address = getCurrentPCValue();
-        NextLine.Loc = DL;
-        EmissionDetails.LineStarts.push_back(NextLine);
-      }
-  
-      PrevDLT = CurDLT;
-    }
+  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 TargetData *TD) {
+                                           const DataLayout *TD) {
   const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
   if (Constants.empty()) return 0;
 
@@ -828,222 +760,21 @@ static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
     MachineConstantPoolEntry CPE = Constants[i];
     unsigned AlignMask = CPE.getAlignment() - 1;
     Size = (Size + AlignMask) & ~AlignMask;
-    const Type *Ty = CPE.getType();
+    Type *Ty = CPE.getType();
     Size += TD->getTypeAllocSize(Ty);
   }
   return Size;
 }
 
-static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
-  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
-  if (JT.empty()) return 0;
-  
-  unsigned NumEntries = 0;
-  for (unsigned i = 0, e = JT.size(); i != e; ++i)
-    NumEntries += JT[i].MBBs.size();
-
-  unsigned EntrySize = MJTI->getEntrySize();
-
-  return NumEntries * EntrySize;
-}
-
-static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
-  if (Alignment == 0) Alignment = 1;
-  // Since we do not know where the buffer will be allocated, be pessimistic. 
-  return Size + Alignment;
-}
-
-/// addSizeOfGlobal - add the size of the global (plus any alignment padding)
-/// into the running total Size.
-
-unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
-  const Type *ElTy = GV->getType()->getElementType();
-  size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy);
-  size_t GVAlign = 
-      (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
-  DEBUG(errs() << "JIT: Adding in size " << GVSize << " alignment " << GVAlign);
-  DEBUG(GV->dump());
-  // Assume code section ends with worst possible alignment, so first
-  // variable needs maximal padding.
-  if (Size==0)
-    Size = 1;
-  Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
-  Size += GVSize;
-  return Size;
-}
-
-/// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
-/// but are referenced from the constant; put them in GVSet and add their
-/// size into the running total Size.
-
-unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C, 
-                                              unsigned Size) {
-  // If its undefined, return the garbage.
-  if (isa<UndefValue>(C))
-    return Size;
-
-  // If the value is a ConstantExpr
-  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
-    Constant *Op0 = CE->getOperand(0);
-    switch (CE->getOpcode()) {
-    case Instruction::GetElementPtr:
-    case Instruction::Trunc:
-    case Instruction::ZExt:
-    case Instruction::SExt:
-    case Instruction::FPTrunc:
-    case Instruction::FPExt:
-    case Instruction::UIToFP:
-    case Instruction::SIToFP:
-    case Instruction::FPToUI:
-    case Instruction::FPToSI:
-    case Instruction::PtrToInt:
-    case Instruction::IntToPtr:
-    case Instruction::BitCast: {
-      Size = addSizeOfGlobalsInConstantVal(Op0, Size);
-      break;
-    }
-    case Instruction::Add:
-    case Instruction::FAdd:
-    case Instruction::Sub:
-    case Instruction::FSub:
-    case Instruction::Mul:
-    case Instruction::FMul:
-    case Instruction::UDiv:
-    case Instruction::SDiv:
-    case Instruction::URem:
-    case Instruction::SRem:
-    case Instruction::And:
-    case Instruction::Or:
-    case Instruction::Xor: {
-      Size = addSizeOfGlobalsInConstantVal(Op0, Size);
-      Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
-      break;
-    }
-    default: {
-       std::string msg;
-       raw_string_ostream Msg(msg);
-       Msg << "ConstantExpr not handled: " << *CE;
-       llvm_report_error(Msg.str());
-    }
-    }
-  }
-
-  if (C->getType()->getTypeID() == Type::PointerTyID)
-    if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
-      if (GVSet.insert(GV))
-        Size = addSizeOfGlobal(GV, Size);
-
-  return Size;
-}
-
-/// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
-/// but are referenced from the given initializer.
-
-unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init, 
-                                              unsigned Size) {
-  if (!isa<UndefValue>(Init) &&
-      !isa<ConstantVector>(Init) &&
-      !isa<ConstantAggregateZero>(Init) &&
-      !isa<ConstantArray>(Init) &&
-      !isa<ConstantStruct>(Init) &&
-      Init->getType()->isFirstClassType())
-    Size = addSizeOfGlobalsInConstantVal(Init, Size);
-  return Size;
-}
-
-/// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
-/// globals; then walk the initializers of those globals looking for more.
-/// If their size has not been considered yet, add it into the running total
-/// Size.
-
-unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
-  unsigned Size = 0;
-  GVSet.clear();
-
-  for (MachineFunction::iterator MBB = MF.begin(), E = MF.end(); 
-       MBB != E; ++MBB) {
-    for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
-         I != E; ++I) {
-      const TargetInstrDesc &Desc = I->getDesc();
-      const MachineInstr &MI = *I;
-      unsigned NumOps = Desc.getNumOperands();
-      for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
-        const MachineOperand &MO = MI.getOperand(CurOp);
-        if (MO.isGlobal()) {
-          GlobalValue* V = MO.getGlobal();
-          const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
-          if (!GV)
-            continue;
-          // If seen in previous function, it will have an entry here.
-          if (TheJIT->getPointerToGlobalIfAvailable(GV))
-            continue;
-          // If seen earlier in this function, it will have an entry here.
-          // FIXME: it should be possible to combine these tables, by
-          // assuming the addresses of the new globals in this module
-          // start at 0 (or something) and adjusting them after codegen
-          // complete.  Another possibility is to grab a marker bit in GV.
-          if (GVSet.insert(GV))
-            // A variable as yet unseen.  Add in its size.
-            Size = addSizeOfGlobal(GV, Size);
-        }
-      }
-    }
-  }
-  DEBUG(errs() << "JIT: About to look through initializers\n");
-  // Look for more globals that are referenced only from initializers.
-  // GVSet.end is computed each time because the set can grow as we go.
-  for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin(); 
-       I != GVSet.end(); I++) {
-    const GlobalVariable* GV = *I;
-    if (GV->hasInitializer())
-      Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
-  }
-
-  return Size;
-}
-
 void JITEmitter::startFunction(MachineFunction &F) {
-  DEBUG(errs() << "JIT: Starting CodeGen of Function "
-        << F.getFunction()->getName() << "\n");
+  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 (MemMgr->NeedsExactSize()) {
-    DEBUG(errs() << "JIT: ExactSize\n");
-    const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
-    MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
-    MachineConstantPool *MCP = F.getConstantPool();
-    
-    // Ensure the constant pool/jump table info is at least 4-byte aligned.
-    ActualSize = RoundUpToAlign(ActualSize, 16);
-    
-    // Add the alignment of the constant pool
-    ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment());
-
-    // Add the constant pool size
-    ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
-
-    // Add the aligment of the jump table info
-    ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
-
-    // Add the jump table size
-    ActualSize += GetJumpTableSizeInBytes(MJTI);
-    
-    // Add the alignment for the function
-    ActualSize = RoundUpToAlign(ActualSize,
-                                std::max(F.getFunction()->getAlignment(), 8U));
-
-    // Add the function size
-    ActualSize += TII->GetFunctionSizeInBytes(F);
-
-    DEBUG(errs() << "JIT: ActualSize before globals " << ActualSize << "\n");
-    // Add the size of the globals that will be allocated after this function.
-    // These are all the ones referenced from this function that were not
-    // previously allocated.
-    ActualSize += GetSizeOfGlobalsInBytes(F);
-    DEBUG(errs() << "JIT: ActualSize after globals " << ActualSize << "\n");
-  } else if (SizeEstimate > 0) {
+
+  if (SizeEstimate > 0) {
     // SizeEstimate will be non-zero on reallocation attempts.
     ActualSize = SizeEstimate;
   }
@@ -1057,11 +788,13 @@ void JITEmitter::startFunction(MachineFunction &F) {
   emitAlignment(16);
 
   emitConstantPool(F.getConstantPool());
-  initJumpTableInfo(F.getJumpTableInfo());
+  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();
 
@@ -1078,7 +811,8 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
     return true;
   }
 
-  emitJumpTableInfo(F.getJumpTableInfo());
+  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.
@@ -1095,39 +829,30 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
     // Resolve the relocations to concrete pointers.
     for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
       MachineRelocation &MR = Relocations[i];
-      void *ResultPtr = 0;
+      void *ResultPtr = nullptr;
       if (!MR.letTargetResolve()) {
         if (MR.isExternalSymbol()) {
           ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
                                                         false);
-          DEBUG(errs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
-                       << ResultPtr << "]\n"); 
+          DEBUG(dbgs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
+                       << ResultPtr << "]\n");
 
           // If the target REALLY wants a stub for this function, emit it now.
-          if (!MR.doesntNeedStub()) {
-            if (!TheJIT->areDlsymStubsEnabled()) {
-              ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
-            } else {
-              void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
-              if (!Stub) {
-                Stub = Resolver.getExternalFunctionStub((void *)&Stub);
-                AddStubToCurrentFunction(Stub);
-              }
-              ResultPtr = Stub;
-            }
+          if (MR.mayNeedFarStub()) {
+            ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
           }
         } else if (MR.isGlobalValue()) {
           ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
                                          BufferBegin+MR.getMachineCodeOffset(),
-                                         MR.doesntNeedStub());
+                                         MR.mayNeedFarStub());
         } else if (MR.isIndirectSymbol()) {
-          ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
-                                          BufferBegin+MR.getMachineCodeOffset(),
-                                          MR.doesntNeedStub());
+          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());
+          ResultPtr =
+            (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
         } else {
           assert(MR.isJumpTableIndex());
           ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
@@ -1142,7 +867,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
         unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
         MR.setGOTIndex(idx);
         if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
-          DEBUG(errs() << "JIT: GOT was out of date for " << ResultPtr
+          DEBUG(dbgs() << "JIT: GOT was out of date for " << ResultPtr
                        << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
                        << "\n");
           ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
@@ -1150,7 +875,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
       }
     }
 
-    CurFn = 0;
+    CurFn = nullptr;
     TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
                                   Relocations.size(), MemMgr->getGOTBase());
   }
@@ -1159,7 +884,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
   if (MemMgr->isManagingGOT()) {
     unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
     if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
-      DEBUG(errs() << "JIT: GOT was out of date for " << (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;
@@ -1179,7 +904,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
     SizeEstimate = 0;
   }
 
-  BufferBegin = CurBufferPtr = 0;
+  BufferBegin = CurBufferPtr = nullptr;
   NumBytes += FnEnd-FnStart;
 
   // Invalidate the icache if necessary.
@@ -1188,8 +913,11 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
   TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
                                 EmissionDetails);
 
-  DEBUG(errs() << "JIT: Finished CodeGen of [" << (void*)FnStart
-        << "] Function: " << F.getFunction()->getName()
+  // 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");
 
@@ -1199,154 +927,67 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
   // Mark code region readable and executable if it's not so already.
   MemMgr->setMemoryExecutable();
 
-  DEBUG(
-    if (sys::hasDisassembler()) {
-      errs() << "JIT: Disassembled code:\n";
-      errs() << sys::disassembleBuffer(FnStart, FnEnd-FnStart,
-                                       (uintptr_t)FnStart);
-    } else {
-      errs() << "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)
-          errs() << "JIT: " << (long)(q - FnStart) << ": ";
-        bool Done = false;
-        for (int j = 3; j >= 0; --j) {
-          if (q + j >= FnEnd)
-            Done = true;
-          else
-            errs() << (unsigned short)q[j];
+  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';
         }
-        if (Done)
-          break;
-        errs() << ' ';
-        if (i == 3)
-          errs() << '\n';
-      }
-      errs()<< '\n';
-    }
-        );
-
-  if (DwarfExceptionHandling || JITEmitDebugInfo) {
-    uintptr_t ActualSize = 0;
-    SavedBufferBegin = BufferBegin;
-    SavedBufferEnd = BufferEnd;
-    SavedCurBufferPtr = CurBufferPtr;
-
-    if (MemMgr->NeedsExactSize()) {
-      ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
-    }
-
-    BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
-                                                             ActualSize);
-    BufferEnd = BufferBegin+ActualSize;
-    EmittedFunctions[F.getFunction()].ExceptionTable = BufferBegin;
-    uint8_t *EhStart;
-    uint8_t *FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd,
-                                                EhStart);
-    MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
-                              FrameRegister);
-    uint8_t *EhEnd = CurBufferPtr;
-    BufferBegin = SavedBufferBegin;
-    BufferEnd = SavedBufferEnd;
-    CurBufferPtr = SavedCurBufferPtr;
-
-    if (DwarfExceptionHandling) {
-      TheJIT->RegisterTable(FrameRegister);
-    }
-
-    if (JITEmitDebugInfo) {
-      DebugInfo I;
-      I.FnStart = FnStart;
-      I.FnEnd = FnEnd;
-      I.EhStart = EhStart;
-      I.EhEnd = EhEnd;
-      DR->RegisterFunction(F.getFunction(), I);
-    }
-  }
+        dbgs()<< '\n';
+    });
 
   if (MMI)
     MMI->EndFunction();
- 
+
   return false;
 }
 
 void JITEmitter::retryWithMoreMemory(MachineFunction &F) {
-  DEBUG(errs() << "JIT: Ran out of space for native code.  Reattempting.\n");
+  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) {
-  DenseMap<const Function *, EmittedCode>::iterator Emitted =
-    EmittedFunctions.find(F);
+  ValueMap<const Function *, EmittedCode, EmittedFunctionConfig>::iterator
+    Emitted = EmittedFunctions.find(F);
   if (Emitted != EmittedFunctions.end()) {
     MemMgr->deallocateFunctionBody(Emitted->second.FunctionBody);
-    MemMgr->deallocateExceptionTable(Emitted->second.ExceptionTable);
-    EmittedFunctions.erase(Emitted);
-  }
-
-  // TODO: Do we need to unregister exception handling information from libgcc
-  // here?
+    TheJIT->NotifyFreeingMachineCode(Emitted->second.Code);
 
-  if (JITEmitDebugInfo) {
-    DR->UnregisterFunction(F);
-  }
-
-  // If the function did not reference any stubs, return.
-  if (CurFnStubUses.find(F) == CurFnStubUses.end())
-    return;
-  
-  // For each referenced stub, erase the reference to this function, and then
-  // erase the list of referenced stubs.
-  SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
-  for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
-    void *Stub = StubList[i];
-    
-    // If we already invalidated this stub for this function, continue.
-    if (StubFnRefs.count(Stub) == 0)
-      continue;
-      
-    SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
-    FnRefs.erase(F);
-    
-    // If this function was the last reference to the stub, invalidate the stub
-    // in the JITResolver.  Were there a memory manager deallocateStub routine,
-    // we could call that at this point too.
-    if (FnRefs.empty()) {
-      DEBUG(errs() << "\nJIT: Invalidated Stub at [" << Stub << "]\n");
-      StubFnRefs.erase(Stub);
-
-      // Invalidate the stub.  If it is a GV stub, update the JIT's global
-      // mapping for that GV to zero, otherwise, search the string map of
-      // external function names to stubs and remove the entry for this stub.
-      GlobalValue *GV = Resolver.invalidateStub(Stub);
-      if (GV) {
-        TheJIT->updateGlobalMapping(GV, 0);
-      } else {
-        for (StringMapIterator<void*> i = ExtFnStubs.begin(),
-             e = ExtFnStubs.end(); i != e; ++i) {
-          if (i->second == Stub) {
-            ExtFnStubs.erase(i);
-            break;
-          }
-        }
-      }
-    }
+    EmittedFunctions.erase(Emitted);
   }
-  CurFnStubUses.erase(F);
 }
 
 
-void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
+void *JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
   if (BufferBegin)
     return JITCodeEmitter::allocateSpace(Size, Alignment);
 
@@ -1358,7 +999,7 @@ void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
   return CurBufferPtr;
 }
 
-void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
+void *JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
   // Delegate this call through the memory manager.
   return MemMgr->allocateGlobal(Size, Alignment);
 }
@@ -1370,14 +1011,14 @@ void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
   const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
   if (Constants.empty()) return;
 
-  unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
+  unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getDataLayout());
   unsigned Align = MCP->getConstantPoolAlignment();
   ConstantPoolBase = allocateSpace(Size, Align);
   ConstantPool = MCP;
 
-  if (ConstantPoolBase == 0) return;  // Buffer overflow.
+  if (!ConstantPoolBase) return;  // Buffer overflow.
 
-  DEBUG(errs() << "JIT: Emitted constant pool at [" << ConstantPoolBase
+  DEBUG(dbgs() << "JIT: Emitted constant pool at [" << ConstantPoolBase
                << "] (size: " << Size << ", alignment: " << Align << ")\n");
 
   // Initialize the memory for all of the constant pool entries.
@@ -1391,36 +1032,39 @@ void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
     ConstPoolAddresses.push_back(CAddr);
     if (CPE.isMachineConstantPoolEntry()) {
       // FIXME: add support to lower machine constant pool values into bytes!
-      llvm_report_error("Initialize memory with machine specific constant pool"
+      report_fatal_error("Initialize memory with machine specific constant pool"
                         "entry has not been implemented!");
     }
     TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
-    DEBUG(errs() << "JIT:   CP" << i << " at [0x";
-          errs().write_hex(CAddr) << "]\n");
+    DEBUG(dbgs() << "JIT:   CP" << i << " at [0x";
+          dbgs().write_hex(CAddr) << "]\n");
 
-    const Type *Ty = CPE.Val.ConstVal->getType();
-    Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty);
+    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();
+  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->getAlignment());
+  JumpTableBase = allocateSpace(NumEntries * EntrySize,
+                             MJTI->getEntryAlignment(*TheJIT->getDataLayout()));
 }
 
 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
@@ -1428,10 +1072,36 @@ void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
     return;
 
   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
-  if (JT.empty() || JumpTableBase == 0) return;
-  
-  if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
-    assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
+  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;
@@ -1443,52 +1113,51 @@ void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
       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);
       }
     }
-  } else {
-    assert(MJTI->getEntrySize() == 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_GPRel64BlockAddress:
+    llvm_unreachable(
+           "JT Info emission not implemented for GPRel64BlockAddress yet.");
   }
 }
 
-void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
-                             unsigned Alignment) {
+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(const GlobalValue* GV, void *Buffer,
-                             unsigned StubSize) {
+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(const GlobalValue* GV) {
+void JITEmitter::finishGVStub() {
+  assert(CurBufferPtr != BufferEnd && "Stub overflowed allocated space.");
   NumBytes += getCurrentPCOffset();
-  std::swap(SavedBufferBegin, BufferBegin);
+  BufferBegin = SavedBufferBegin;
   BufferEnd = SavedBufferEnd;
   CurBufferPtr = SavedCurBufferPtr;
-  return SavedBufferBegin;
+}
+
+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
@@ -1507,18 +1176,29 @@ uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
 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;
-  unsigned EntrySize = JumpTable->getEntrySize();
-  
   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
 //===----------------------------------------------------------------------===//
@@ -1528,19 +1208,6 @@ JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM,
   return new JITEmitter(jit, JMM, tm);
 }
 
-// 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.
-extern "C" {
-  void *getPointerToNamedFunction(const char *Name) {
-    if (Function *F = TheJIT->FindFunctionNamed(Name))
-      return TheJIT->getPointerToFunction(F);
-    return TheJIT->getPointerToNamedFunction(Name);
-  }
-}
-
 // 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.
@@ -1549,123 +1216,34 @@ 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.
-  assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
-  JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
-  return JE->getJITResolver().getFunctionStub(F);
+  JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
+  return JE->getJITResolver().getLazyFunctionStub(F);
 }
 
-void JIT::updateFunctionStub(Function *F) {
+void JIT::updateFunctionStubUnlocked(Function *F) {
   // Get the empty stub we generated earlier.
-  assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
-  JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
-  void *Stub = JE->getJITResolver().getFunctionStub(F);
+  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.
-  void *Addr = getPointerToGlobalIfAvailable(F);
-  getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
-}
-
-/// updateDlsymStubTable - Emit the data necessary to relocate the stubs
-/// that were emitted during code generation.
-///
-void JIT::updateDlsymStubTable() {
-  assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
-  JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
-  
-  SmallVector<GlobalValue*, 8> GVs;
-  SmallVector<void*, 8> Ptrs;
-  const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
-
-  JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
-
-  unsigned nStubs = GVs.size() + ExtFns.size();
-  
-  // If there are no relocatable stubs, return.
-  if (nStubs == 0)
-    return;
-
-  // If there are no new relocatable stubs, return.
-  void *CurTable = JE->getMemMgr()->getDlsymTable();
-  if (CurTable && (*(unsigned *)CurTable == nStubs))
-    return;
-  
-  // Calculate the size of the stub info
-  unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
-  
-  SmallVector<unsigned, 8> Offsets;
-  for (unsigned i = 0; i != GVs.size(); ++i) {
-    Offsets.push_back(offset);
-    offset += GVs[i]->getName().size() + 1;
-  }
-  for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 
-       i != e; ++i) {
-    Offsets.push_back(offset);
-    offset += strlen(i->first()) + 1;
-  }
-  
-  // Allocate space for the new "stub", which contains the dlsym table.
-  JE->startGVStub(0, offset, 4);
-  
-  // Emit the number of records
-  JE->emitInt32(nStubs);
-  
-  // Emit the string offsets
-  for (unsigned i = 0; i != nStubs; ++i)
-    JE->emitInt32(Offsets[i]);
-  
-  // Emit the pointers.  Verify that they are at least 2-byte aligned, and set
-  // the low bit to 0 == GV, 1 == Function, so that the client code doing the
-  // relocation can write the relocated pointer at the appropriate place in
-  // the stub.
-  for (unsigned i = 0; i != GVs.size(); ++i) {
-    intptr_t Ptr = (intptr_t)Ptrs[i];
-    assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
-    
-    if (isa<Function>(GVs[i]))
-      Ptr |= (intptr_t)1;
-           
-    if (sizeof(Ptr) == 8)
-      JE->emitInt64(Ptr);
-    else
-      JE->emitInt32(Ptr);
-  }
-  for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 
-       i != e; ++i) {
-    intptr_t Ptr = (intptr_t)i->second | 1;
-
-    if (sizeof(Ptr) == 8)
-      JE->emitInt64(Ptr);
-    else
-      JE->emitInt32(Ptr);
-  }
-  
-  // Emit the strings.
-  for (unsigned i = 0; i != GVs.size(); ++i)
-    JE->emitString(GVs[i]->getName());
-  for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 
-       i != e; ++i)
-    JE->emitString(i->first());
-  
-  // Tell the JIT memory manager where it is.  The JIT Memory Manager will
-  // deallocate space for the old one, if one existed.
-  JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
+  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.
-  void *OldPtr = updateGlobalMapping(F, 0);
-
-  if (OldPtr)
-    TheJIT->NotifyFreeingMachineCode(*F, OldPtr);
+  updateGlobalMapping(F, nullptr);
 
   // Free the actual memory for the function body and related stuff.
-  assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
-  cast<JITEmitter>(JCE)->deallocateMemForFunction(F);
+  static_cast<JITEmitter*>(JCE)->deallocateMemForFunction(F);
 }