Update LLVM for 3.5 rebase (r209712).

Change-Id: I149556c940fb7dc92d075273c87ff584f400941f

42 files changed, 1687 insertions, 912 deletions

diff --git a/lib/IR/Android.mk b/lib/IR/Android.mk
index 071bb04..dd95703 100644
--- a/lib/IR/Android.mk
+++ b/lib/IR/Android.mk
@@ -30,6 +30,7 @@ vmcore_SRC_FILES := \
   LeakDetector.cpp \
   LegacyPassManager.cpp \
   Mangler.cpp \
+  MDBuilder.cpp \
   Metadata.cpp \
   Module.cpp \
   Pass.cpp \
diff --git a/lib/IR/AsmWriter.cpp b/lib/IR/AsmWriter.cpp
index d4670e4..0fef0d0 100644
--- a/lib/IR/AsmWriter.cpp
+++ b/lib/IR/AsmWriter.cpp
@@ -51,19 +51,19 @@ AssemblyAnnotationWriter::~AssemblyAnnotationWriter() {}
 
 static const Module *getModuleFromVal(const Value *V) {
   if (const Argument *MA = dyn_cast<Argument>(V))
-    return MA->getParent() ? MA->getParent()->getParent() : 0;
+    return MA->getParent() ? MA->getParent()->getParent() : nullptr;
 
   if (const BasicBlock *BB = dyn_cast<BasicBlock>(V))
-    return BB->getParent() ? BB->getParent()->getParent() : 0;
+    return BB->getParent() ? BB->getParent()->getParent() : nullptr;
 
   if (const Instruction *I = dyn_cast<Instruction>(V)) {
-    const Function *M = I->getParent() ? I->getParent()->getParent() : 0;
-    return M ? M->getParent() : 0;
+    const Function *M = I->getParent() ? I->getParent()->getParent() : nullptr;
+    return M ? M->getParent() : nullptr;
   }
 
   if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
     return GV->getParent();
-  return 0;
+  return nullptr;
 }
 
 static void PrintCallingConv(unsigned cc, raw_ostream &Out) {
@@ -78,7 +78,6 @@ static void PrintCallingConv(unsigned cc, raw_ostream &Out) {
   case CallingConv::X86_StdCall:   Out << "x86_stdcallcc"; break;
   case CallingConv::X86_FastCall:  Out << "x86_fastcallcc"; break;
   case CallingConv::X86_ThisCall:  Out << "x86_thiscallcc"; break;
-  case CallingConv::X86_CDeclMethod:Out << "x86_cdeclmethodcc"; break;
   case CallingConv::Intel_OCL_BI:  Out << "intel_ocl_bicc"; break;
   case CallingConv::ARM_APCS:      Out << "arm_apcscc"; break;
   case CallingConv::ARM_AAPCS:     Out << "arm_aapcscc"; break;
@@ -421,10 +420,10 @@ static SlotTracker *createSlotTracker(const Value *V) {
     if (!MD->isFunctionLocal())
       return new SlotTracker(MD->getFunction());
 
-    return new SlotTracker((Function *)0);
+    return new SlotTracker((Function *)nullptr);
   }
 
-  return 0;
+  return nullptr;
 }
 
 #if 0
@@ -436,21 +435,21 @@ static SlotTracker *createSlotTracker(const Value *V) {
 // Module level constructor. Causes the contents of the Module (sans functions)
 // to be added to the slot table.
 SlotTracker::SlotTracker(const Module *M)
-  : TheModule(M), TheFunction(0), FunctionProcessed(false),
+  : TheModule(M), TheFunction(nullptr), FunctionProcessed(false),
     mNext(0), fNext(0),  mdnNext(0), asNext(0) {
 }
 
 // Function level constructor. Causes the contents of the Module and the one
 // function provided to be added to the slot table.
 SlotTracker::SlotTracker(const Function *F)
-  : TheModule(F ? F->getParent() : 0), TheFunction(F), FunctionProcessed(false),
-    mNext(0), fNext(0), mdnNext(0), asNext(0) {
+  : TheModule(F ? F->getParent() : nullptr), TheFunction(F),
+    FunctionProcessed(false), mNext(0), fNext(0), mdnNext(0), asNext(0) {
 }
 
 inline void SlotTracker::initialize() {
   if (TheModule) {
     processModule();
-    TheModule = 0; ///< Prevent re-processing next time we're called.
+    TheModule = nullptr; ///< Prevent re-processing next time we're called.
   }
 
   if (TheFunction && !FunctionProcessed)
@@ -560,7 +559,7 @@ void SlotTracker::processFunction() {
 void SlotTracker::purgeFunction() {
   ST_DEBUG("begin purgeFunction!\n");
   fMap.clear(); // Simply discard the function level map
-  TheFunction = 0;
+  TheFunction = nullptr;
   FunctionProcessed = false;
   ST_DEBUG("end purgeFunction!\n");
 }
@@ -1048,7 +1047,7 @@ static void WriteMDNodeBodyInternal(raw_ostream &Out, const MDNode *Node,
   Out << "!{";
   for (unsigned mi = 0, me = Node->getNumOperands(); mi != me; ++mi) {
     const Value *V = Node->getOperand(mi);
-    if (V == 0)
+    if (!V)
       Out << "null";
     else {
       TypePrinter->print(V->getType(), Out);
@@ -1126,12 +1125,6 @@ static void WriteAsOperandInternal(raw_ostream &Out, const Value *V,
     return;
   }
 
-  if (V->getValueID() == Value::PseudoSourceValueVal ||
-      V->getValueID() == Value::FixedStackPseudoSourceValueVal) {
-    V->print(Out);
-    return;
-  }
-
   char Prefix = '%';
   int Slot;
   // If we have a SlotTracker, use it.
@@ -1160,7 +1153,7 @@ static void WriteAsOperandInternal(raw_ostream &Out, const Value *V,
       Slot = Machine->getLocalSlot(V);
     }
     delete Machine;
-    Machine = 0;
+    Machine = nullptr;
   } else {
     Slot = -1;
   }
@@ -1194,7 +1187,7 @@ AssemblyWriter::AssemblyWriter(formatted_raw_ostream &o, const Module *M,
 AssemblyWriter::~AssemblyWriter() { }
 
 void AssemblyWriter::writeOperand(const Value *Operand, bool PrintType) {
-  if (Operand == 0) {
+  if (!Operand) {
     Out << "<null operand!>";
     return;
   }
@@ -1259,7 +1252,7 @@ void AssemblyWriter::writeAtomicCmpXchg(AtomicOrdering SuccessOrdering,
 
 void AssemblyWriter::writeParamOperand(const Value *Operand,
                                        AttributeSet Attrs, unsigned Idx) {
-  if (Operand == 0) {
+  if (!Operand) {
     Out << "<null operand!>";
     return;
   }
@@ -1500,10 +1493,16 @@ void AssemblyWriter::printAlias(const GlobalAlias *GA) {
 
   PrintLinkage(GA->getLinkage(), Out);
 
+  PointerType *Ty = GA->getType();
   const Constant *Aliasee = GA->getAliasee();
+  if (!Aliasee || Ty != Aliasee->getType()) {
+    if (unsigned AddressSpace = Ty->getAddressSpace())
+      Out << "addrspace(" << AddressSpace << ") ";
+    TypePrinter.print(Ty->getElementType(), Out);
+    Out << ", ";
+  }
 
-  if (Aliasee == 0) {
-    TypePrinter.print(GA->getType(), Out);
+  if (!Aliasee) {
     Out << " <<NULL ALIASEE>>";
   } else {
     writeOperand(Aliasee, !isa<ConstantExpr>(Aliasee));
@@ -1707,7 +1706,7 @@ void AssemblyWriter::printBasicBlock(const BasicBlock *BB) {
       Out << "<badref>";
   }
 
-  if (BB->getParent() == 0) {
+  if (!BB->getParent()) {
     Out.PadToColumn(50);
     Out << "; Error: Block without parent!";
   } else if (BB != &BB->getParent()->getEntryBlock()) {  // Not the entry block?
@@ -1774,8 +1773,12 @@ void AssemblyWriter::printInstruction(const Instruction &I) {
       Out << '%' << SlotNum << " = ";
   }
 
-  if (isa<CallInst>(I) && cast<CallInst>(I).isTailCall())
-    Out << "tail ";
+  if (const CallInst *CI = dyn_cast<CallInst>(&I)) {
+    if (CI->isMustTailCall())
+      Out << "musttail ";
+    else if (CI->isTailCall())
+      Out << "tail ";
+  }
 
   // Print out the opcode...
   Out << I.getOpcodeName();
@@ -1804,7 +1807,7 @@ void AssemblyWriter::printInstruction(const Instruction &I) {
     writeAtomicRMWOperation(Out, RMWI->getOperation());
 
   // Print out the type of the operands...
-  const Value *Operand = I.getNumOperands() ? I.getOperand(0) : 0;
+  const Value *Operand = I.getNumOperands() ? I.getOperand(0) : nullptr;
 
   // Special case conditional branches to swizzle the condition out to the front
   if (isa<BranchInst>(I) && cast<BranchInst>(I).isConditional()) {
@@ -2147,15 +2150,15 @@ void Module::print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW) const {
   W.printModule(this);
 }
 
-void NamedMDNode::print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW) const {
+void NamedMDNode::print(raw_ostream &ROS) const {
   SlotTracker SlotTable(getParent());
   formatted_raw_ostream OS(ROS);
-  AssemblyWriter W(OS, SlotTable, getParent(), AAW);
+  AssemblyWriter W(OS, SlotTable, getParent(), nullptr);
   W.printNamedMDNode(this);
 }
 
 void Type::print(raw_ostream &OS) const {
-  if (this == 0) {
+  if (!this) {
     OS << "<null Type>";
     return;
   }
@@ -2170,24 +2173,24 @@ void Type::print(raw_ostream &OS) const {
     }
 }
 
-void Value::print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW) const {
-  if (this == 0) {
+void Value::print(raw_ostream &ROS) const {
+  if (!this) {
     ROS << "printing a <null> value\n";
     return;
   }
   formatted_raw_ostream OS(ROS);
   if (const Instruction *I = dyn_cast<Instruction>(this)) {
-    const Function *F = I->getParent() ? I->getParent()->getParent() : 0;
+    const Function *F = I->getParent() ? I->getParent()->getParent() : nullptr;
     SlotTracker SlotTable(F);
-    AssemblyWriter W(OS, SlotTable, getModuleFromVal(I), AAW);
+    AssemblyWriter W(OS, SlotTable, getModuleFromVal(I), nullptr);
     W.printInstruction(*I);
   } else if (const BasicBlock *BB = dyn_cast<BasicBlock>(this)) {
     SlotTracker SlotTable(BB->getParent());
-    AssemblyWriter W(OS, SlotTable, getModuleFromVal(BB), AAW);
+    AssemblyWriter W(OS, SlotTable, getModuleFromVal(BB), nullptr);
     W.printBasicBlock(BB);
   } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(this)) {
     SlotTracker SlotTable(GV->getParent());
-    AssemblyWriter W(OS, SlotTable, GV->getParent(), AAW);
+    AssemblyWriter W(OS, SlotTable, GV->getParent(), nullptr);
     if (const GlobalVariable *V = dyn_cast<GlobalVariable>(GV))
       W.printGlobal(V);
     else if (const Function *F = dyn_cast<Function>(GV))
@@ -2197,20 +2200,18 @@ void Value::print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW) const {
   } else if (const MDNode *N = dyn_cast<MDNode>(this)) {
     const Function *F = N->getFunction();
     SlotTracker SlotTable(F);
-    AssemblyWriter W(OS, SlotTable, F ? F->getParent() : 0, AAW);
+    AssemblyWriter W(OS, SlotTable, F ? F->getParent() : nullptr, nullptr);
     W.printMDNodeBody(N);
   } else if (const Constant *C = dyn_cast<Constant>(this)) {
     TypePrinting TypePrinter;
     TypePrinter.print(C->getType(), OS);
     OS << ' ';
-    WriteConstantInternal(OS, C, TypePrinter, 0, 0);
+    WriteConstantInternal(OS, C, TypePrinter, nullptr, nullptr);
   } else if (isa<InlineAsm>(this) || isa<MDString>(this) ||
              isa<Argument>(this)) {
     this->printAsOperand(OS);
   } else {
-    // Otherwise we don't know what it is. Call the virtual function to
-    // allow a subclass to print itself.
-    printCustom(OS);
+    llvm_unreachable("Unknown value to print out!");
   }
 }
 
@@ -2220,7 +2221,7 @@ void Value::printAsOperand(raw_ostream &O, bool PrintType, const Module *M) cons
   if (!PrintType &&
       ((!isa<Constant>(this) && !isa<MDNode>(this)) ||
        hasName() || isa<GlobalValue>(this))) {
-    WriteAsOperandInternal(O, this, 0, 0, M);
+    WriteAsOperandInternal(O, this, nullptr, nullptr, M);
     return;
   }
 
@@ -2235,12 +2236,7 @@ void Value::printAsOperand(raw_ostream &O, bool PrintType, const Module *M) cons
     O << ' ';
   }
 
-  WriteAsOperandInternal(O, this, &TypePrinter, 0, M);
-}
-
-// Value::printCustom - subclasses should override this to implement printing.
-void Value::printCustom(raw_ostream &OS) const {
-  llvm_unreachable("Unknown value to print out!");
+  WriteAsOperandInternal(O, this, &TypePrinter, nullptr, M);
 }
 
 // Value::dump - allow easy printing of Values from the debugger.
@@ -2250,7 +2246,7 @@ void Value::dump() const { print(dbgs()); dbgs() << '\n'; }
 void Type::dump() const { print(dbgs()); }
 
 // Module::dump() - Allow printing of Modules from the debugger.
-void Module::dump() const { print(dbgs(), 0); }
+void Module::dump() const { print(dbgs(), nullptr); }
 
 // NamedMDNode::dump() - Allow printing of NamedMDNodes from the debugger.
-void NamedMDNode::dump() const { print(dbgs(), 0); }
+void NamedMDNode::dump() const { print(dbgs()); }
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index 9d9d948..a9074bb 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -16,6 +16,7 @@
 #include "llvm/IR/Attributes.h"
 #include "AttributeImpl.h"
 #include "LLVMContextImpl.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/Atomic.h"
@@ -192,6 +193,8 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
     return "noinline";
   if (hasAttribute(Attribute::NonLazyBind))
     return "nonlazybind";
+  if (hasAttribute(Attribute::NonNull))
+    return "nonnull";
   if (hasAttribute(Attribute::NoRedZone))
     return "noredzone";
   if (hasAttribute(Attribute::NoReturn))
@@ -391,6 +394,7 @@ uint64_t AttributeImpl::getAttrMask(Attribute::AttrKind Val) {
   case Attribute::Builtin:         return 1ULL << 41;
   case Attribute::OptimizeNone:    return 1ULL << 42;
   case Attribute::InAlloca:        return 1ULL << 43;
+  case Attribute::NonNull:         return 1ULL << 44;
   }
   llvm_unreachable("Unsupported attribute type");
 }
@@ -402,7 +406,7 @@ uint64_t AttributeImpl::getAttrMask(Attribute::AttrKind Val) {
 AttributeSetNode *AttributeSetNode::get(LLVMContext &C,
                                         ArrayRef<Attribute> Attrs) {
   if (Attrs.empty())
-    return 0;
+    return nullptr;
 
   // Otherwise, build a key to look up the existing attributes.
   LLVMContextImpl *pImpl = C.pImpl;
@@ -595,7 +599,8 @@ AttributeSet AttributeSet::get(LLVMContext &C,
   return getImpl(C, Attrs);
 }
 
-AttributeSet AttributeSet::get(LLVMContext &C, unsigned Index, AttrBuilder &B) {
+AttributeSet AttributeSet::get(LLVMContext &C, unsigned Index,
+                               const AttrBuilder &B) {
   if (!B.hasAttributes())
     return AttributeSet();
 
@@ -617,9 +622,9 @@ AttributeSet AttributeSet::get(LLVMContext &C, unsigned Index, AttrBuilder &B) {
   }
 
   // Add target-dependent (string) attributes.
-  for (AttrBuilder::td_iterator I = B.td_begin(), E = B.td_end();
-       I != E; ++I)
-    Attrs.push_back(std::make_pair(Index, Attribute::get(C, I->first,I->second)));
+  for (const AttrBuilder::td_type &TDA : B.td_attrs())
+    Attrs.push_back(
+        std::make_pair(Index, Attribute::get(C, TDA.first, TDA.second)));
 
   return get(C, Attrs);
 }
@@ -836,7 +841,7 @@ bool AttributeSet::hasAttributes(unsigned Index) const {
 /// \brief Return true if the specified attribute is set for at least one
 /// parameter or for the return value.
 bool AttributeSet::hasAttrSomewhere(Attribute::AttrKind Attr) const {
-  if (pImpl == 0) return false;
+  if (!pImpl) return false;
 
   for (unsigned I = 0, E = pImpl->getNumAttributes(); I != E; ++I)
     for (AttributeSetImpl::iterator II = pImpl->begin(I),
@@ -877,14 +882,14 @@ std::string AttributeSet::getAsString(unsigned Index,
 
 /// \brief The attributes for the specified index are returned.
 AttributeSetNode *AttributeSet::getAttributes(unsigned Index) const {
-  if (!pImpl) return 0;
+  if (!pImpl) return nullptr;
 
   // Loop through to find the attribute node we want.
   for (unsigned I = 0, E = pImpl->getNumAttributes(); I != E; ++I)
     if (pImpl->getSlotIndex(I) == Index)
       return pImpl->getSlotNode(I);
 
-  return 0;
+  return nullptr;
 }
 
 AttributeSet::iterator AttributeSet::begin(unsigned Slot) const {
@@ -1175,6 +1180,7 @@ AttributeSet AttributeFuncs::typeIncompatible(Type *Ty, uint64_t Index) {
       .addAttribute(Attribute::Nest)
       .addAttribute(Attribute::NoAlias)
       .addAttribute(Attribute::NoCapture)
+      .addAttribute(Attribute::NonNull)
       .addAttribute(Attribute::ReadNone)
       .addAttribute(Attribute::ReadOnly)
       .addAttribute(Attribute::StructRet)
diff --git a/lib/IR/AutoUpgrade.cpp b/lib/IR/AutoUpgrade.cpp
index b7429b3..e255113 100644
--- a/lib/IR/AutoUpgrade.cpp
+++ b/lib/IR/AutoUpgrade.cpp
@@ -115,7 +115,7 @@ static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
         Name == "x86.avx.movnt.ps.256" ||
         Name == "x86.sse42.crc32.64.8" ||
         (Name.startswith("x86.xop.vpcom") && F->arg_size() == 2)) {
-      NewFn = 0;
+      NewFn = nullptr;
       return true;
     }
     // SSE4.1 ptest functions may have an old signature.
@@ -158,7 +158,7 @@ static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
 }
 
 bool llvm::UpgradeIntrinsicFunction(Function *F, Function *&NewFn) {
-  NewFn = 0;
+  NewFn = nullptr;
   bool Upgraded = UpgradeIntrinsicFunction1(F, NewFn);
 
   // Upgrade intrinsic attributes.  This does not change the function.
@@ -170,7 +170,62 @@ bool llvm::UpgradeIntrinsicFunction(Function *F, Function *&NewFn) {
   return Upgraded;
 }
 
+static bool UpgradeGlobalStructors(GlobalVariable *GV) {
+  ArrayType *ATy = dyn_cast<ArrayType>(GV->getType()->getElementType());
+  StructType *OldTy =
+      ATy ? dyn_cast<StructType>(ATy->getElementType()) : nullptr;
+
+  // Only upgrade an array of a two field struct with the appropriate field
+  // types.
+  if (!OldTy || OldTy->getNumElements() != 2)
+    return false;
+
+  // Get the upgraded 3 element type.
+  PointerType *VoidPtrTy = Type::getInt8Ty(GV->getContext())->getPointerTo();
+  Type *Tys[3] = {
+    OldTy->getElementType(0),
+    OldTy->getElementType(1),
+    VoidPtrTy
+  };
+  StructType *NewTy =
+      StructType::get(GV->getContext(), Tys, /*isPacked=*/false);
+
+  // Build new constants with a null third field filled in.
+  Constant *OldInitC = GV->getInitializer();
+  ConstantArray *OldInit = dyn_cast<ConstantArray>(OldInitC);
+  if (!OldInit && !isa<ConstantAggregateZero>(OldInitC))
+    return false;
+  std::vector<Constant *> Initializers;
+  if (OldInit) {
+    for (Use &U : OldInit->operands()) {
+      ConstantStruct *Init = cast<ConstantStruct>(&U);
+      Constant *NewInit =
+        ConstantStruct::get(NewTy, Init->getOperand(0), Init->getOperand(1),
+                            Constant::getNullValue(VoidPtrTy), nullptr);
+      Initializers.push_back(NewInit);
+    }
+  }
+  assert(Initializers.size() == ATy->getNumElements());
+
+  // Replace the old GV with a new one.
+  ATy = ArrayType::get(NewTy, Initializers.size());
+  Constant *NewInit = ConstantArray::get(ATy, Initializers);
+  GlobalVariable *NewGV = new GlobalVariable(
+      *GV->getParent(), ATy, GV->isConstant(), GV->getLinkage(), NewInit, "",
+      GV, GV->getThreadLocalMode(), GV->getType()->getAddressSpace(),
+      GV->isExternallyInitialized());
+  NewGV->copyAttributesFrom(GV);
+  NewGV->takeName(GV);
+  assert(GV->use_empty() && "program cannot use initializer list");
+  GV->eraseFromParent();
+  return true;
+}
+
 bool llvm::UpgradeGlobalVariable(GlobalVariable *GV) {
+  if (GV->getName() == "llvm.global_ctors" ||
+      GV->getName() == "llvm.global_dtors")
+    return UpgradeGlobalStructors(GV);
+
   // Nothing to do yet.
   return false;
 }
@@ -453,9 +508,9 @@ void llvm::UpgradeInstWithTBAATag(Instruction *I) {
 Instruction *llvm::UpgradeBitCastInst(unsigned Opc, Value *V, Type *DestTy,
                                       Instruction *&Temp) {
   if (Opc != Instruction::BitCast)
-    return 0;
+    return nullptr;
 
-  Temp = 0;
+  Temp = nullptr;
   Type *SrcTy = V->getType();
   if (SrcTy->isPtrOrPtrVectorTy() && DestTy->isPtrOrPtrVectorTy() &&
       SrcTy->getPointerAddressSpace() != DestTy->getPointerAddressSpace()) {
@@ -469,12 +524,12 @@ Instruction *llvm::UpgradeBitCastInst(unsigned Opc, Value *V, Type *DestTy,
     return CastInst::Create(Instruction::IntToPtr, Temp, DestTy);
   }
 
-  return 0;
+  return nullptr;
 }
 
 Value *llvm::UpgradeBitCastExpr(unsigned Opc, Constant *C, Type *DestTy) {
   if (Opc != Instruction::BitCast)
-    return 0;
+    return nullptr;
 
   Type *SrcTy = C->getType();
   if (SrcTy->isPtrOrPtrVectorTy() && DestTy->isPtrOrPtrVectorTy() &&
@@ -489,7 +544,7 @@ Value *llvm::UpgradeBitCastExpr(unsigned Opc, Constant *C, Type *DestTy) {
                                      DestTy);
   }
 
-  return 0;
+  return nullptr;
 }
 
 /// Check the debug info version number, if it is out-dated, drop the debug
diff --git a/lib/IR/BasicBlock.cpp b/lib/IR/BasicBlock.cpp
index 3079f0a..ba07433 100644
--- a/lib/IR/BasicBlock.cpp
+++ b/lib/IR/BasicBlock.cpp
@@ -27,7 +27,7 @@ using namespace llvm;
 ValueSymbolTable *BasicBlock::getValueSymbolTable() {
   if (Function *F = getParent())
     return &F->getValueSymbolTable();
-  return 0;
+  return nullptr;
 }
 
 const DataLayout *BasicBlock::getDataLayout() const {
@@ -45,7 +45,7 @@ template class llvm::SymbolTableListTraits<Instruction, BasicBlock>;
 
 BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent,
                        BasicBlock *InsertBefore)
-  : Value(Type::getLabelTy(C), Value::BasicBlockVal), Parent(0) {
+  : Value(Type::getLabelTy(C), Value::BasicBlockVal), Parent(nullptr) {
 
   // Make sure that we get added to a function
   LeakDetector::addGarbageObject(this);
@@ -81,7 +81,7 @@ BasicBlock::~BasicBlock() {
     }
   }
 
-  assert(getParent() == 0 && "BasicBlock still linked into the program!");
+  assert(getParent() == nullptr && "BasicBlock still linked into the program!");
   dropAllReferences();
   InstList.clear();
 }
@@ -122,12 +122,12 @@ void BasicBlock::moveAfter(BasicBlock *MovePos) {
 
 
 TerminatorInst *BasicBlock::getTerminator() {
-  if (InstList.empty()) return 0;
+  if (InstList.empty()) return nullptr;
   return dyn_cast<TerminatorInst>(&InstList.back());
 }
 
 const TerminatorInst *BasicBlock::getTerminator() const {
-  if (InstList.empty()) return 0;
+  if (InstList.empty()) return nullptr;
   return dyn_cast<TerminatorInst>(&InstList.back());
 }
 
@@ -186,10 +186,10 @@ void BasicBlock::dropAllReferences() {
 /// return the block, otherwise return a null pointer.
 BasicBlock *BasicBlock::getSinglePredecessor() {
   pred_iterator PI = pred_begin(this), E = pred_end(this);
-  if (PI == E) return 0;         // No preds.
+  if (PI == E) return nullptr;         // No preds.
   BasicBlock *ThePred = *PI;
   ++PI;
-  return (PI == E) ? ThePred : 0 /*multiple preds*/;
+  return (PI == E) ? ThePred : nullptr /*multiple preds*/;
 }
 
 /// getUniquePredecessor - If this basic block has a unique predecessor block,
@@ -199,12 +199,12 @@ BasicBlock *BasicBlock::getSinglePredecessor() {
 /// a switch statement with multiple cases having the same destination).
 BasicBlock *BasicBlock::getUniquePredecessor() {
   pred_iterator PI = pred_begin(this), E = pred_end(this);
-  if (PI == E) return 0; // No preds.
+  if (PI == E) return nullptr; // No preds.
   BasicBlock *PredBB = *PI;
   ++PI;
   for (;PI != E; ++PI) {
     if (*PI != PredBB)
-      return 0;
+      return nullptr;
     // The same predecessor appears multiple times in the predecessor list.
     // This is OK.
   }
@@ -277,7 +277,7 @@ void BasicBlock::removePredecessor(BasicBlock *Pred,
       PN->removeIncomingValue(Pred, false);
       // If all incoming values to the Phi are the same, we can replace the Phi
       // with that value.
-      Value* PNV = 0;
+      Value* PNV = nullptr;
       if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue()))
         if (PNV != PN) {
           PN->replaceAllUsesWith(PNV);
diff --git a/lib/IR/CMakeLists.txt b/lib/IR/CMakeLists.txt
index 09117aa..b027ae5 100644
--- a/lib/IR/CMakeLists.txt
+++ b/lib/IR/CMakeLists.txt
@@ -7,12 +7,12 @@ add_llvm_library(LLVMCore
   ConstantRange.cpp
   Constants.cpp
   Core.cpp
-  DiagnosticInfo.cpp
-  DiagnosticPrinter.cpp
   DIBuilder.cpp
   DataLayout.cpp
   DebugInfo.cpp
   DebugLoc.cpp
+  DiagnosticInfo.cpp
+  DiagnosticPrinter.cpp
   Dominators.cpp
   Function.cpp
   GCOV.cpp
@@ -28,6 +28,7 @@ add_llvm_library(LLVMCore
   LLVMContextImpl.cpp
   LeakDetector.cpp
   LegacyPassManager.cpp
+  MDBuilder.cpp
   Mangler.cpp
   Metadata.cpp
   Module.cpp
diff --git a/lib/IR/ConstantFold.cpp b/lib/IR/ConstantFold.cpp
index 612aba0..706e66f 100644
--- a/lib/IR/ConstantFold.cpp
+++ b/lib/IR/ConstantFold.cpp
@@ -51,7 +51,7 @@ static Constant *BitCastConstantVector(Constant *CV, VectorType *DstTy) {
   // Analysis/ConstantFolding.cpp
   unsigned NumElts = DstTy->getNumElements();
   if (NumElts != CV->getType()->getVectorNumElements())
-    return 0;
+    return nullptr;
   
   Type *DstEltTy = DstTy->getElementType();
 
@@ -94,7 +94,7 @@ foldConstantCastPair(
 
   // Let CastInst::isEliminableCastPair do the heavy lifting.
   return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
-                                        0, FakeIntPtrTy, 0);
+                                        nullptr, FakeIntPtrTy, nullptr);
 }
 
 static Constant *FoldBitCast(Constant *V, Type *DestTy) {
@@ -139,7 +139,7 @@ static Constant *FoldBitCast(Constant *V, Type *DestTy) {
     if (VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
       assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
              "Not cast between same sized vectors!");
-      SrcTy = NULL;
+      SrcTy = nullptr;
       // First, check for null.  Undef is already handled.
       if (isa<ConstantAggregateZero>(V))
         return Constant::getNullValue(DestTy);
@@ -173,7 +173,7 @@ static Constant *FoldBitCast(Constant *V, Type *DestTy) {
                                      CI->getValue()));
 
     // Otherwise, can't fold this (vector?)
-    return 0;
+    return nullptr;
   }
 
   // Handle ConstantFP input: FP -> Integral.
@@ -181,7 +181,7 @@ static Constant *FoldBitCast(Constant *V, Type *DestTy) {
     return ConstantInt::get(FP->getContext(),
                             FP->getValueAPF().bitcastToAPInt());
 
-  return 0;
+  return nullptr;
 }
 
 
@@ -216,14 +216,14 @@ static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
   // In the input is a constant expr, we might be able to recursively simplify.
   // If not, we definitely can't do anything.
   ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
-  if (CE == 0) return 0;
-  
+  if (!CE) return nullptr;
+
   switch (CE->getOpcode()) {
-  default: return 0;
+  default: return nullptr;
   case Instruction::Or: {
     Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
-    if (RHS == 0)
-      return 0;
+    if (!RHS)
+      return nullptr;
     
     // X | -1 -> -1.
     if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS))
@@ -231,32 +231,32 @@ static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
         return RHSC;
     
     Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
-    if (LHS == 0)
-      return 0;
+    if (!LHS)
+      return nullptr;
     return ConstantExpr::getOr(LHS, RHS);
   }
   case Instruction::And: {
     Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
-    if (RHS == 0)
-      return 0;
+    if (!RHS)
+      return nullptr;
     
     // X & 0 -> 0.
     if (RHS->isNullValue())
       return RHS;
     
     Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
-    if (LHS == 0)
-      return 0;
+    if (!LHS)
+      return nullptr;
     return ConstantExpr::getAnd(LHS, RHS);
   }
   case Instruction::LShr: {
     ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
-    if (Amt == 0)
-      return 0;
+    if (!Amt)
+      return nullptr;
     unsigned ShAmt = Amt->getZExtValue();
     // Cannot analyze non-byte shifts.
     if ((ShAmt & 7) != 0)
-      return 0;
+      return nullptr;
     ShAmt >>= 3;
     
     // If the extract is known to be all zeros, return zero.
@@ -268,17 +268,17 @@ static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
       return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
     
     // TODO: Handle the 'partially zero' case.
-    return 0;
+    return nullptr;
   }
     
   case Instruction::Shl: {
     ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
-    if (Amt == 0)
-      return 0;
+    if (!Amt)
+      return nullptr;
     unsigned ShAmt = Amt->getZExtValue();
     // Cannot analyze non-byte shifts.
     if ((ShAmt & 7) != 0)
-      return 0;
+      return nullptr;
     ShAmt >>= 3;
     
     // If the extract is known to be all zeros, return zero.
@@ -290,7 +290,7 @@ static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
       return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
     
     // TODO: Handle the 'partially zero' case.
-    return 0;
+    return nullptr;
   }
       
   case Instruction::ZExt: {
@@ -324,7 +324,7 @@ static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
     }
     
     // TODO: Handle the 'partially zero' case.
-    return 0;
+    return nullptr;
   }
   }
 }
@@ -376,7 +376,7 @@ static Constant *getFoldedSizeOf(Type *Ty, Type *DestTy,
   // If there's no interesting folding happening, bail so that we don't create
   // a constant that looks like it needs folding but really doesn't.
   if (!Folded)
-    return 0;
+    return nullptr;
 
   // Base case: Get a regular sizeof expression.
   Constant *C = ConstantExpr::getSizeOf(Ty);
@@ -442,7 +442,7 @@ static Constant *getFoldedAlignOf(Type *Ty, Type *DestTy,
   // If there's no interesting folding happening, bail so that we don't create
   // a constant that looks like it needs folding but really doesn't.
   if (!Folded)
-    return 0;
+    return nullptr;
 
   // Base case: Get a regular alignof expression.
   Constant *C = ConstantExpr::getAlignOf(Ty);
@@ -473,7 +473,7 @@ static Constant *getFoldedOffsetOf(Type *Ty, Constant *FieldNo,
       unsigned NumElems = STy->getNumElements();
       // An empty struct has no members.
       if (NumElems == 0)
-        return 0;
+        return nullptr;
       // Check for a struct with all members having the same size.
       Constant *MemberSize =
         getFoldedSizeOf(STy->getElementType(0), DestTy, true);
@@ -497,7 +497,7 @@ static Constant *getFoldedOffsetOf(Type *Ty, Constant *FieldNo,
   // If there's no interesting folding happening, bail so that we don't create
   // a constant that looks like it needs folding but really doesn't.
   if (!Folded)
-    return 0;
+    return nullptr;
 
   // Base case: Get a regular offsetof expression.
   Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
@@ -582,7 +582,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
                   APFloat::rmNearestTiesToEven, &ignored);
       return ConstantFP::get(V->getContext(), Val);
     }
-    return 0; // Can't fold.
+    return nullptr; // Can't fold.
   case Instruction::FPToUI: 
   case Instruction::FPToSI:
     if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
@@ -595,11 +595,11 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
       APInt Val(DestBitWidth, x);
       return ConstantInt::get(FPC->getContext(), Val);
     }
-    return 0; // Can't fold.
+    return nullptr; // Can't fold.
   case Instruction::IntToPtr:   //always treated as unsigned
     if (V->isNullValue())       // Is it an integral null value?
       return ConstantPointerNull::get(cast<PointerType>(DestTy));
-    return 0;                   // Other pointer types cannot be casted
+    return nullptr;                   // Other pointer types cannot be casted
   case Instruction::PtrToInt:   // always treated as unsigned
     // Is it a null pointer value?
     if (V->isNullValue())
@@ -643,7 +643,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
         }
       }
     // Other pointer types cannot be casted
-    return 0;
+    return nullptr;
   case Instruction::UIToFP:
   case Instruction::SIToFP:
     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
@@ -655,21 +655,21 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
                                  APFloat::rmNearestTiesToEven);
       return ConstantFP::get(V->getContext(), apf);
     }
-    return 0;
+    return nullptr;
   case Instruction::ZExt:
     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       return ConstantInt::get(V->getContext(),
                               CI->getValue().zext(BitWidth));
     }
-    return 0;
+    return nullptr;
   case Instruction::SExt:
     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       return ConstantInt::get(V->getContext(),
                               CI->getValue().sext(BitWidth));
     }
-    return 0;
+    return nullptr;
   case Instruction::Trunc: {
     uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
@@ -685,12 +685,12 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
       if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
         return Res;
       
-    return 0;
+    return nullptr;
   }
   case Instruction::BitCast:
     return FoldBitCast(V, DestTy);
   case Instruction::AddrSpaceCast:
-    return 0;
+    return nullptr;
   }
 }
 
@@ -746,7 +746,7 @@ Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
         return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
   }
 
-  return 0;
+  return nullptr;
 }
 
 Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
@@ -766,14 +766,14 @@ Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
       return UndefValue::get(Val->getType()->getVectorElementType());
     return Val->getAggregateElement(Index);
   }
-  return 0;
+  return nullptr;
 }
 
 Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
                                                      Constant *Elt,
                                                      Constant *Idx) {
   ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
-  if (!CIdx) return 0;
+  if (!CIdx) return nullptr;
   const APInt &IdxVal = CIdx->getValue();
   
   SmallVector<Constant*, 16> Result;
@@ -803,7 +803,7 @@ Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
     return UndefValue::get(VectorType::get(EltTy, MaskNumElts));
 
   // Don't break the bitcode reader hack.
-  if (isa<ConstantExpr>(Mask)) return 0;
+  if (isa<ConstantExpr>(Mask)) return nullptr;
   
   unsigned SrcNumElts = V1->getType()->getVectorNumElements();
 
@@ -842,7 +842,7 @@ Constant *llvm::ConstantFoldExtractValueInstruction(Constant *Agg,
   if (Constant *C = Agg->getAggregateElement(Idxs[0]))
     return ConstantFoldExtractValueInstruction(C, Idxs.slice(1));
 
-  return 0;
+  return nullptr;
 }
 
 Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
@@ -863,8 +863,8 @@ Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
   SmallVector<Constant*, 32> Result;
   for (unsigned i = 0; i != NumElts; ++i) {
     Constant *C = Agg->getAggregateElement(i);
-    if (C == 0) return 0;
-    
+    if (!C) return nullptr;
+
     if (Idxs[0] == i)
       C = ConstantFoldInsertValueInstruction(C, Val, Idxs.slice(1));
     
@@ -1209,7 +1209,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
   }
 
   // We don't know how to fold this.
-  return 0;
+  return nullptr;
 }
 
 /// isZeroSizedType - This type is zero sized if its an array or structure of
@@ -1289,7 +1289,7 @@ static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2) {
   if (!isa<ConstantExpr>(V1)) {
     if (!isa<ConstantExpr>(V2)) {
       // We distilled thisUse the standard constant folder for a few cases
-      ConstantInt *R = 0;
+      ConstantInt *R = nullptr;
       R = dyn_cast<ConstantInt>(
                       ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, V1, V2));
       if (R && !R->isZero()) 
@@ -1355,7 +1355,7 @@ static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
         !isa<BlockAddress>(V2)) {
       // We distilled this down to a simple case, use the standard constant
       // folder.
-      ConstantInt *R = 0;
+      ConstantInt *R = nullptr;
       ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
       R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
       if (R && !R->isZero()) 
@@ -1885,7 +1885,7 @@ Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
       return ConstantExpr::getICmp(pred, C2, C1);
     }
   }
-  return 0;
+  return nullptr;
 }
 
 /// isInBoundsIndices - Test whether the given sequence of *normalized* indices
@@ -1951,7 +1951,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
   if (isa<UndefValue>(C)) {
     PointerType *Ptr = cast<PointerType>(C->getType());
     Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
-    assert(Ty != 0 && "Invalid indices for GEP!");
+    assert(Ty && "Invalid indices for GEP!");
     return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
   }
 
@@ -1965,7 +1965,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
     if (isNull) {
       PointerType *Ptr = cast<PointerType>(C->getType());
       Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
-      assert(Ty != 0 && "Invalid indices for GEP!");
+      assert(Ty && "Invalid indices for GEP!");
       return ConstantPointerNull::get(PointerType::get(Ty,
                                                        Ptr->getAddressSpace()));
     }
@@ -1977,7 +1977,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
     // getelementptr instructions into a single instruction.
     //
     if (CE->getOpcode() == Instruction::GetElementPtr) {
-      Type *LastTy = 0;
+      Type *LastTy = nullptr;
       for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
            I != E; ++I)
         LastTy = *I;
@@ -2072,7 +2072,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
   bool Unknown = false;
   SmallVector<Constant *, 8> NewIdxs;
   Type *Ty = C->getType();
-  Type *Prev = 0;
+  Type *Prev = nullptr;
   for (unsigned i = 0, e = Idxs.size(); i != e;
        Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
     if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
@@ -2130,7 +2130,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
       isa<GlobalVariable>(C) && isInBoundsIndices(Idxs))
     return ConstantExpr::getInBoundsGetElementPtr(C, Idxs);
 
-  return 0;
+  return nullptr;
 }
 
 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
diff --git a/lib/IR/Constants.cpp b/lib/IR/Constants.cpp
index 2a3a5fd..bb8d60b 100644
--- a/lib/IR/Constants.cpp
+++ b/lib/IR/Constants.cpp
@@ -182,13 +182,13 @@ Constant *Constant::getAllOnesValue(Type *Ty) {
 /// 'this' is a constant expr.
 Constant *Constant::getAggregateElement(unsigned Elt) const {
   if (const ConstantStruct *CS = dyn_cast<ConstantStruct>(this))
-    return Elt < CS->getNumOperands() ? CS->getOperand(Elt) : 0;
+    return Elt < CS->getNumOperands() ? CS->getOperand(Elt) : nullptr;
 
   if (const ConstantArray *CA = dyn_cast<ConstantArray>(this))
-    return Elt < CA->getNumOperands() ? CA->getOperand(Elt) : 0;
+    return Elt < CA->getNumOperands() ? CA->getOperand(Elt) : nullptr;
 
   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
-    return Elt < CV->getNumOperands() ? CV->getOperand(Elt) : 0;
+    return Elt < CV->getNumOperands() ? CV->getOperand(Elt) : nullptr;
 
   if (const ConstantAggregateZero *CAZ =dyn_cast<ConstantAggregateZero>(this))
     return CAZ->getElementValue(Elt);
@@ -197,15 +197,16 @@ Constant *Constant::getAggregateElement(unsigned Elt) const {
     return UV->getElementValue(Elt);
 
   if (const ConstantDataSequential *CDS =dyn_cast<ConstantDataSequential>(this))
-    return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt) : 0;
-  return 0;
+    return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt)
+                                       : nullptr;
+  return nullptr;
 }
 
 Constant *Constant::getAggregateElement(Constant *Elt) const {
   assert(isa<IntegerType>(Elt->getType()) && "Index must be an integer");
   if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt))
     return getAggregateElement(CI->getZExtValue());
-  return 0;
+  return nullptr;
 }
 
 
@@ -309,7 +310,7 @@ bool Constant::isThreadDependent() const {
 bool Constant::isConstantUsed() const {
   for (const User *U : users()) {
     const Constant *UC = dyn_cast<Constant>(U);
-    if (UC == 0 || isa<GlobalValue>(UC))
+    if (!UC || isa<GlobalValue>(UC))
       return true;
 
     if (UC->isConstantUsed())
@@ -397,7 +398,7 @@ void Constant::removeDeadConstantUsers() const {
   Value::const_user_iterator LastNonDeadUser = E;
   while (I != E) {
     const Constant *User = dyn_cast<Constant>(*I);
-    if (User == 0) {
+    if (!User) {
       LastNonDeadUser = I;
       ++I;
       continue;
@@ -431,7 +432,7 @@ void Constant::removeDeadConstantUsers() const {
 void ConstantInt::anchor() { }
 
 ConstantInt::ConstantInt(IntegerType *Ty, const APInt& V)
-  : Constant(Ty, ConstantIntVal, 0, 0), Val(V) {
+  : Constant(Ty, ConstantIntVal, nullptr, 0), Val(V) {
   assert(V.getBitWidth() == Ty->getBitWidth() && "Invalid constant for type");
 }
 
@@ -644,7 +645,7 @@ Constant *ConstantFP::getInfinity(Type *Ty, bool Negative) {
 }
 
 ConstantFP::ConstantFP(Type *Ty, const APFloat& V)
-  : Constant(Ty, ConstantFPVal, 0, 0), Val(V) {
+  : Constant(Ty, ConstantFPVal, nullptr, 0), Val(V) {
   assert(&V.getSemantics() == TypeToFloatSemantics(Ty) &&
          "FP type Mismatch");
 }
@@ -1235,7 +1236,7 @@ ConstantAggregateZero *ConstantAggregateZero::get(Type *Ty) {
          "Cannot create an aggregate zero of non-aggregate type!");
   
   ConstantAggregateZero *&Entry = Ty->getContext().pImpl->CAZConstants[Ty];
-  if (Entry == 0)
+  if (!Entry)
     Entry = new ConstantAggregateZero(Ty);
 
   return Entry;
@@ -1283,7 +1284,7 @@ Constant *Constant::getSplatValue() const {
     return CV->getSplatValue();
   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
     return CV->getSplatValue();
-  return 0;
+  return nullptr;
 }
 
 /// getSplatValue - If this is a splat constant, where all of the
@@ -1294,7 +1295,7 @@ Constant *ConstantVector::getSplatValue() const {
   // Then make sure all remaining elements point to the same value.
   for (unsigned I = 1, E = getNumOperands(); I < E; ++I)
     if (getOperand(I) != Elt)
-      return 0;
+      return nullptr;
   return Elt;
 }
 
@@ -1315,7 +1316,7 @@ const APInt &Constant::getUniqueInteger() const {
 
 ConstantPointerNull *ConstantPointerNull::get(PointerType *Ty) {
   ConstantPointerNull *&Entry = Ty->getContext().pImpl->CPNConstants[Ty];
-  if (Entry == 0)
+  if (!Entry)
     Entry = new ConstantPointerNull(Ty);
 
   return Entry;
@@ -1335,7 +1336,7 @@ void ConstantPointerNull::destroyConstant() {
 
 UndefValue *UndefValue::get(Type *Ty) {
   UndefValue *&Entry = Ty->getContext().pImpl->UVConstants[Ty];
-  if (Entry == 0)
+  if (!Entry)
     Entry = new UndefValue(Ty);
 
   return Entry;
@@ -1353,14 +1354,14 @@ void UndefValue::destroyConstant() {
 //
 
 BlockAddress *BlockAddress::get(BasicBlock *BB) {
-  assert(BB->getParent() != 0 && "Block must have a parent");
+  assert(BB->getParent() && "Block must have a parent");
   return get(BB->getParent(), BB);
 }
 
 BlockAddress *BlockAddress::get(Function *F, BasicBlock *BB) {
   BlockAddress *&BA =
     F->getContext().pImpl->BlockAddresses[std::make_pair(F, BB)];
-  if (BA == 0)
+  if (!BA)
     BA = new BlockAddress(F, BB);
 
   assert(BA->getFunction() == F && "Basic block moved between functions");
@@ -1377,10 +1378,10 @@ BlockAddress::BlockAddress(Function *F, BasicBlock *BB)
 
 BlockAddress *BlockAddress::lookup(const BasicBlock *BB) {
   if (!BB->hasAddressTaken())
-    return 0;
+    return nullptr;
 
   const Function *F = BB->getParent();
-  assert(F != 0 && "Block must have a parent");
+  assert(F && "Block must have a parent");
   BlockAddress *BA =
       F->getContext().pImpl->BlockAddresses.lookup(std::make_pair(F, BB));
   assert(BA && "Refcount and block address map disagree!");
@@ -1411,7 +1412,7 @@ void BlockAddress::replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
   // and return early.
   BlockAddress *&NewBA =
     getContext().pImpl->BlockAddresses[std::make_pair(NewF, NewBB)];
-  if (NewBA == 0) {
+  if (!NewBA) {
     getBasicBlock()->AdjustBlockAddressRefCount(-1);
 
     // Remove the old entry, this can't cause the map to rehash (just a
@@ -1792,7 +1793,7 @@ Constant *ConstantExpr::getAlignOf(Type* Ty) {
   // Note that a non-inbounds gep is used, as null isn't within any object.
   Type *AligningTy = 
     StructType::get(Type::getInt1Ty(Ty->getContext()), Ty, NULL);
-  Constant *NullPtr = Constant::getNullValue(AligningTy->getPointerTo());
+  Constant *NullPtr = Constant::getNullValue(AligningTy->getPointerTo(0));
   Constant *Zero = ConstantInt::get(Type::getInt64Ty(Ty->getContext()), 0);
   Constant *One = ConstantInt::get(Type::getInt32Ty(Ty->getContext()), 1);
   Constant *Indices[2] = { Zero, One };
@@ -1936,8 +1937,8 @@ ConstantExpr::getFCmp(unsigned short pred, Constant *LHS, Constant *RHS) {
 Constant *ConstantExpr::getExtractElement(Constant *Val, Constant *Idx) {
   assert(Val->getType()->isVectorTy() &&
          "Tried to create extractelement operation on non-vector type!");
-  assert(Idx->getType()->isIntegerTy(32) &&
-         "Extractelement index must be i32 type!");
+  assert(Idx->getType()->isIntegerTy() &&
+         "Extractelement index must be an integer type!");
 
   if (Constant *FC = ConstantFoldExtractElementInstruction(Val, Idx))
     return FC;          // Fold a few common cases.
@@ -1957,7 +1958,7 @@ Constant *ConstantExpr::getInsertElement(Constant *Val, Constant *Elt,
          "Tried to create insertelement operation on non-vector type!");
   assert(Elt->getType() == Val->getType()->getVectorElementType() &&
          "Insertelement types must match!");
-  assert(Idx->getType()->isIntegerTy(32) &&
+  assert(Idx->getType()->isIntegerTy() &&
          "Insertelement index must be i32 type!");
 
   if (Constant *FC = ConstantFoldInsertElementInstruction(Val, Elt, Idx))
@@ -2145,7 +2146,7 @@ Constant *ConstantExpr::getBinOpIdentity(unsigned Opcode, Type *Ty) {
   switch (Opcode) {
   default:
     // Doesn't have an identity.
-    return 0;
+    return nullptr;
 
   case Instruction::Add:
   case Instruction::Or:
@@ -2168,7 +2169,7 @@ Constant *ConstantExpr::getBinOpAbsorber(unsigned Opcode, Type *Ty) {
   switch (Opcode) {
   default:
     // Doesn't have an absorber.
-    return 0;
+    return nullptr;
 
   case Instruction::Or:
     return Constant::getAllOnesValue(Ty);
@@ -2285,7 +2286,7 @@ Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
   // of i8, or a 1-element array of i32.  They'll both end up in the same
   /// StringMap bucket, linked up by their Next pointers.  Walk the list.
   ConstantDataSequential **Entry = &Slot.getValue();
-  for (ConstantDataSequential *Node = *Entry; Node != 0;
+  for (ConstantDataSequential *Node = *Entry; Node;
        Entry = &Node->Next, Node = *Entry)
     if (Node->getType() == Ty)
       return Node;
@@ -2312,7 +2313,7 @@ void ConstantDataSequential::destroyConstant() {
   ConstantDataSequential **Entry = &Slot->getValue();
 
   // Remove the entry from the hash table.
-  if ((*Entry)->Next == 0) {
+  if (!(*Entry)->Next) {
     // If there is only one value in the bucket (common case) it must be this
     // entry, and removing the entry should remove the bucket completely.
     assert((*Entry) == this && "Hash mismatch in ConstantDataSequential");
@@ -2333,7 +2334,7 @@ void ConstantDataSequential::destroyConstant() {
 
   // If we were part of a list, make sure that we don't delete the list that is
   // still owned by the uniquing map.
-  Next = 0;
+  Next = nullptr;
 
   // Finally, actually delete it.
   destroyConstantImpl();
@@ -2561,7 +2562,7 @@ Constant *ConstantDataVector::getSplatValue() const {
   unsigned EltSize = getElementByteSize();
   for (unsigned i = 1, e = getNumElements(); i != e; ++i)
     if (memcmp(Base, Base+i*EltSize, EltSize))
-      return 0;
+      return nullptr;
 
   // If they're all the same, return the 0th one as a representative.
   return getElementAsConstant(0);
@@ -2609,7 +2610,7 @@ void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
     AllSame &= Val == ToC;
   }
 
-  Constant *Replacement = 0;
+  Constant *Replacement = nullptr;
   if (AllSame && ToC->isNullValue()) {
     Replacement = ConstantAggregateZero::get(getType());
   } else if (AllSame && isa<UndefValue>(ToC)) {
@@ -2695,7 +2696,7 @@ void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
 
   LLVMContextImpl *pImpl = getContext().pImpl;
 
-  Constant *Replacement = 0;
+  Constant *Replacement = nullptr;
   if (isAllZeros) {
     Replacement = ConstantAggregateZero::get(getType());
   } else if (isAllUndef) {
diff --git a/lib/IR/ConstantsContext.h b/lib/IR/ConstantsContext.h
index 59b9d4d..f06509f 100644
--- a/lib/IR/ConstantsContext.h
+++ b/lib/IR/ConstantsContext.h
@@ -24,6 +24,9 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include <map>
+#include <tuple>
+
+#define DEBUG_TYPE "ir"
 
 namespace llvm {
 template<class ValType>
@@ -584,7 +587,7 @@ public:
   /// necessary.
   ConstantClass *getOrCreate(TypeClass *Ty, ValRefType V) {
     MapKey Lookup(Ty, V);
-    ConstantClass* Result = 0;
+    ConstantClass* Result = nullptr;
     
     typename MapTy::iterator I = Map.find(Lookup);
     // Is it in the map?  
@@ -720,7 +723,7 @@ public:
   /// necessary.
   ConstantClass *getOrCreate(TypeClass *Ty, Operands V) {
     LookupKey Lookup(Ty, V);
-    ConstantClass* Result = 0;
+    ConstantClass* Result = nullptr;
 
     typename MapTy::iterator I = Map.find_as(Lookup);
     // Is it in the map?
diff --git a/lib/IR/Core.cpp b/lib/IR/Core.cpp
index f52f466..27ce503 100644
--- a/lib/IR/Core.cpp
+++ b/lib/IR/Core.cpp
@@ -17,6 +17,8 @@
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalVariable.h"
@@ -28,6 +30,7 @@
 #include "llvm/PassManager.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Threading.h"
@@ -39,6 +42,8 @@
 
 using namespace llvm;
 
+#define DEBUG_TYPE "ir"
+
 void llvm::initializeCore(PassRegistry &Registry) {
   initializeDominatorTreeWrapperPassPass(Registry);
   initializePrintModulePassWrapperPass(Registry);
@@ -76,6 +81,21 @@ LLVMContextRef LLVMGetGlobalContext() {
   return wrap(&getGlobalContext());
 }
 
+void LLVMContextSetDiagnosticHandler(LLVMContextRef C,
+                                     LLVMDiagnosticHandler Handler,
+                                     void *DiagnosticContext) {
+  unwrap(C)->setDiagnosticHandler(
+      LLVM_EXTENSION reinterpret_cast<LLVMContext::DiagnosticHandlerTy>(Handler),
+      DiagnosticContext);
+}
+
+void LLVMContextSetYieldCallback(LLVMContextRef C, LLVMYieldCallback Callback,
+                                 void *OpaqueHandle) {
+  auto YieldCallback =
+    LLVM_EXTENSION reinterpret_cast<LLVMContext::YieldCallbackTy>(Callback);
+  unwrap(C)->setYieldCallback(YieldCallback, OpaqueHandle);
+}
+
 void LLVMContextDispose(LLVMContextRef C) {
   delete unwrap(C);
 }
@@ -89,6 +109,40 @@ unsigned LLVMGetMDKindID(const char* Name, unsigned SLen) {
   return LLVMGetMDKindIDInContext(LLVMGetGlobalContext(), Name, SLen);
 }
 
+char *LLVMGetDiagInfoDescription(LLVMDiagnosticInfoRef DI) {
+  std::string MsgStorage;
+  raw_string_ostream Stream(MsgStorage);
+  DiagnosticPrinterRawOStream DP(Stream);
+
+  unwrap(DI)->print(DP);
+  Stream.flush();
+
+  return LLVMCreateMessage(MsgStorage.c_str());
+}
+
+LLVMDiagnosticSeverity LLVMGetDiagInfoSeverity(LLVMDiagnosticInfoRef DI){
+    LLVMDiagnosticSeverity severity;
+
+    switch(unwrap(DI)->getSeverity()) {
+    default:
+      severity = LLVMDSError;
+      break;
+    case DS_Warning:
+      severity = LLVMDSWarning;
+      break;
+    case DS_Remark:
+      severity = LLVMDSRemark;
+      break;
+    case DS_Note:
+      severity = LLVMDSNote;
+      break;
+    }
+
+    return severity;
+}
+
+
+
 
 /*===-- Operations on modules ---------------------------------------------===*/
 
@@ -136,7 +190,7 @@ LLVMBool LLVMPrintModuleToFile(LLVMModuleRef M, const char *Filename,
     return true;
   }
 
-  unwrap(M)->print(dest, NULL);
+  unwrap(M)->print(dest, nullptr);
 
   if (!error.empty()) {
     *ErrorMessage = strdup(error.c_str());
@@ -150,7 +204,7 @@ char *LLVMPrintModuleToString(LLVMModuleRef M) {
   std::string buf;
   raw_string_ostream os(buf);
 
-  unwrap(M)->print(os, NULL);
+  unwrap(M)->print(os, nullptr);
   os.flush();
 
   return strdup(buf.c_str());
@@ -374,7 +428,7 @@ const char *LLVMGetStructName(LLVMTypeRef Ty)
 {
   StructType *Type = unwrap<StructType>(Ty);
   if (!Type->hasName())
-    return 0;
+    return nullptr;
   return Type->getName().data();
 }
 
@@ -496,7 +550,8 @@ LLVMValueRef LLVMGetMetadata(LLVMValueRef Inst, unsigned KindID) {
 }
 
 void LLVMSetMetadata(LLVMValueRef Inst, unsigned KindID, LLVMValueRef MD) {
-  unwrap<Instruction>(Inst)->setMetadata(KindID, MD? unwrap<MDNode>(MD) : NULL);
+  unwrap<Instruction>(Inst)->setMetadata(KindID,
+                                         MD ? unwrap<MDNode>(MD) : nullptr);
 }
 
 /*--.. Conversion functions ................................................--*/
@@ -513,7 +568,7 @@ LLVMUseRef LLVMGetFirstUse(LLVMValueRef Val) {
   Value *V = unwrap(Val);
   Value::use_iterator I = V->use_begin();
   if (I == V->use_end())
-    return 0;
+    return nullptr;
   return wrap(&*I);
 }
 
@@ -521,7 +576,7 @@ LLVMUseRef LLVMGetNextUse(LLVMUseRef U) {
   Use *Next = unwrap(U)->getNext();
   if (Next)
     return wrap(Next);
-  return 0;
+  return nullptr;
 }
 
 LLVMValueRef LLVMGetUser(LLVMUseRef U) {
@@ -611,7 +666,7 @@ const char *LLVMGetMDString(LLVMValueRef V, unsigned* Len) {
     return S->getString().data();
   }
   *Len = 0;
-  return 0;
+  return nullptr;
 }
 
 unsigned LLVMGetMDNodeNumOperands(LLVMValueRef V)
@@ -650,7 +705,7 @@ void LLVMAddNamedMetadataOperand(LLVMModuleRef M, const char* name,
   NamedMDNode *N = unwrap(M)->getOrInsertNamedMetadata(name);
   if (!N)
     return;
-  MDNode *Op = Val ? unwrap<MDNode>(Val) : NULL;
+  MDNode *Op = Val ? unwrap<MDNode>(Val) : nullptr;
   if (Op)
     N->addOperand(Op);
 }
@@ -1235,7 +1290,7 @@ const char *LLVMGetSection(LLVMValueRef Global) {
 }
 
 void LLVMSetSection(LLVMValueRef Global, const char *Section) {
-  unwrap<GlobalValue>(Global)->setSection(Section);
+  unwrap<GlobalObject>(Global)->setSection(Section);
 }
 
 LLVMVisibility LLVMGetVisibility(LLVMValueRef Global) {
@@ -1285,7 +1340,7 @@ unsigned LLVMGetAlignment(LLVMValueRef V) {
 
 void LLVMSetAlignment(LLVMValueRef V, unsigned Bytes) {
   Value *P = unwrap<Value>(V);
-  if (GlobalValue *GV = dyn_cast<GlobalValue>(P))
+  if (GlobalObject *GV = dyn_cast<GlobalObject>(P))
     GV->setAlignment(Bytes);
   else if (AllocaInst *AI = dyn_cast<AllocaInst>(P))
     AI->setAlignment(Bytes);
@@ -1302,15 +1357,16 @@ void LLVMSetAlignment(LLVMValueRef V, unsigned Bytes) {
 
 LLVMValueRef LLVMAddGlobal(LLVMModuleRef M, LLVMTypeRef Ty, const char *Name) {
   return wrap(new GlobalVariable(*unwrap(M), unwrap(Ty), false,
-                                 GlobalValue::ExternalLinkage, 0, Name));
+                                 GlobalValue::ExternalLinkage, nullptr, Name));
 }
 
 LLVMValueRef LLVMAddGlobalInAddressSpace(LLVMModuleRef M, LLVMTypeRef Ty,
                                          const char *Name,
                                          unsigned AddressSpace) {
   return wrap(new GlobalVariable(*unwrap(M), unwrap(Ty), false,
-                                 GlobalValue::ExternalLinkage, 0, Name, 0,
-                                 GlobalVariable::NotThreadLocal, AddressSpace));
+                                 GlobalValue::ExternalLinkage, nullptr, Name,
+                                 nullptr, GlobalVariable::NotThreadLocal,
+                                 AddressSpace));
 }
 
 LLVMValueRef LLVMGetNamedGlobal(LLVMModuleRef M, const char *Name) {
@@ -1321,7 +1377,7 @@ LLVMValueRef LLVMGetFirstGlobal(LLVMModuleRef M) {
   Module *Mod = unwrap(M);
   Module::global_iterator I = Mod->global_begin();
   if (I == Mod->global_end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1329,7 +1385,7 @@ LLVMValueRef LLVMGetLastGlobal(LLVMModuleRef M) {
   Module *Mod = unwrap(M);
   Module::global_iterator I = Mod->global_end();
   if (I == Mod->global_begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1337,7 +1393,7 @@ LLVMValueRef LLVMGetNextGlobal(LLVMValueRef GlobalVar) {
   GlobalVariable *GV = unwrap<GlobalVariable>(GlobalVar);
   Module::global_iterator I = GV;
   if (++I == GV->getParent()->global_end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1345,7 +1401,7 @@ LLVMValueRef LLVMGetPreviousGlobal(LLVMValueRef GlobalVar) {
   GlobalVariable *GV = unwrap<GlobalVariable>(GlobalVar);
   Module::global_iterator I = GV;
   if (I == GV->getParent()->global_begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1356,7 +1412,7 @@ void LLVMDeleteGlobal(LLVMValueRef GlobalVar) {
 LLVMValueRef LLVMGetInitializer(LLVMValueRef GlobalVar) {
   GlobalVariable* GV = unwrap<GlobalVariable>(GlobalVar);
   if ( !GV->hasInitializer() )
-    return 0;
+    return nullptr;
   return wrap(GV->getInitializer());
 }
 
@@ -1432,8 +1488,10 @@ void LLVMSetExternallyInitialized(LLVMValueRef GlobalVar, LLVMBool IsExtInit) {
 
 LLVMValueRef LLVMAddAlias(LLVMModuleRef M, LLVMTypeRef Ty, LLVMValueRef Aliasee,
                           const char *Name) {
-  return wrap(new GlobalAlias(unwrap(Ty), GlobalValue::ExternalLinkage, Name,
-                              unwrap<Constant>(Aliasee), unwrap (M)));
+  auto *PTy = cast<PointerType>(unwrap(Ty));
+  return wrap(GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
+                                  GlobalValue::ExternalLinkage, Name,
+                                  unwrap<GlobalObject>(Aliasee), unwrap(M)));
 }
 
 /*--.. Operations on functions .............................................--*/
@@ -1452,7 +1510,7 @@ LLVMValueRef LLVMGetFirstFunction(LLVMModuleRef M) {
   Module *Mod = unwrap(M);
   Module::iterator I = Mod->begin();
   if (I == Mod->end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1460,7 +1518,7 @@ LLVMValueRef LLVMGetLastFunction(LLVMModuleRef M) {
   Module *Mod = unwrap(M);
   Module::iterator I = Mod->end();
   if (I == Mod->begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1468,7 +1526,7 @@ LLVMValueRef LLVMGetNextFunction(LLVMValueRef Fn) {
   Function *Func = unwrap<Function>(Fn);
   Module::iterator I = Func;
   if (++I == Func->getParent()->end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1476,7 +1534,7 @@ LLVMValueRef LLVMGetPreviousFunction(LLVMValueRef Fn) {
   Function *Func = unwrap<Function>(Fn);
   Module::iterator I = Func;
   if (I == Func->getParent()->begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1501,7 +1559,7 @@ void LLVMSetFunctionCallConv(LLVMValueRef Fn, unsigned CC) {
 
 const char *LLVMGetGC(LLVMValueRef Fn) {
   Function *F = unwrap<Function>(Fn);
-  return F->hasGC()? F->getGC() : 0;
+  return F->hasGC()? F->getGC() : nullptr;
 }
 
 void LLVMSetGC(LLVMValueRef Fn, const char *GC) {
@@ -1582,7 +1640,7 @@ LLVMValueRef LLVMGetFirstParam(LLVMValueRef Fn) {
   Function *Func = unwrap<Function>(Fn);
   Function::arg_iterator I = Func->arg_begin();
   if (I == Func->arg_end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1590,7 +1648,7 @@ LLVMValueRef LLVMGetLastParam(LLVMValueRef Fn) {
   Function *Func = unwrap<Function>(Fn);
   Function::arg_iterator I = Func->arg_end();
   if (I == Func->arg_begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1598,7 +1656,7 @@ LLVMValueRef LLVMGetNextParam(LLVMValueRef Arg) {
   Argument *A = unwrap<Argument>(Arg);
   Function::arg_iterator I = A;
   if (++I == A->getParent()->arg_end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1606,7 +1664,7 @@ LLVMValueRef LLVMGetPreviousParam(LLVMValueRef Arg) {
   Argument *A = unwrap<Argument>(Arg);
   Function::arg_iterator I = A;
   if (I == A->getParent()->arg_begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1676,7 +1734,7 @@ LLVMBasicBlockRef LLVMGetFirstBasicBlock(LLVMValueRef Fn) {
   Function *Func = unwrap<Function>(Fn);
   Function::iterator I = Func->begin();
   if (I == Func->end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1684,7 +1742,7 @@ LLVMBasicBlockRef LLVMGetLastBasicBlock(LLVMValueRef Fn) {
   Function *Func = unwrap<Function>(Fn);
   Function::iterator I = Func->end();
   if (I == Func->begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1692,7 +1750,7 @@ LLVMBasicBlockRef LLVMGetNextBasicBlock(LLVMBasicBlockRef BB) {
   BasicBlock *Block = unwrap(BB);
   Function::iterator I = Block;
   if (++I == Block->getParent()->end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1700,7 +1758,7 @@ LLVMBasicBlockRef LLVMGetPreviousBasicBlock(LLVMBasicBlockRef BB) {
   BasicBlock *Block = unwrap(BB);
   Function::iterator I = Block;
   if (I == Block->getParent()->begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1752,7 +1810,7 @@ LLVMValueRef LLVMGetFirstInstruction(LLVMBasicBlockRef BB) {
   BasicBlock *Block = unwrap(BB);
   BasicBlock::iterator I = Block->begin();
   if (I == Block->end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1760,7 +1818,7 @@ LLVMValueRef LLVMGetLastInstruction(LLVMBasicBlockRef BB) {
   BasicBlock *Block = unwrap(BB);
   BasicBlock::iterator I = Block->end();
   if (I == Block->begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1768,7 +1826,7 @@ LLVMValueRef LLVMGetNextInstruction(LLVMValueRef Inst) {
   Instruction *Instr = unwrap<Instruction>(Inst);
   BasicBlock::iterator I = Instr;
   if (++I == Instr->getParent()->end())
-    return 0;
+    return nullptr;
   return wrap(I);
 }
 
@@ -1776,7 +1834,7 @@ LLVMValueRef LLVMGetPreviousInstruction(LLVMValueRef Inst) {
   Instruction *Instr = unwrap<Instruction>(Inst);
   BasicBlock::iterator I = Instr;
   if (I == Instr->getParent()->begin())
-    return 0;
+    return nullptr;
   return wrap(--I);
 }
 
@@ -1939,7 +1997,7 @@ void LLVMDisposeBuilder(LLVMBuilderRef Builder) {
 /*--.. Metadata builders ...................................................--*/
 
 void LLVMSetCurrentDebugLocation(LLVMBuilderRef Builder, LLVMValueRef L) {
-  MDNode *Loc = L ? unwrap<MDNode>(L) : NULL;
+  MDNode *Loc = L ? unwrap<MDNode>(L) : nullptr;
   unwrap(Builder)->SetCurrentDebugLocation(DebugLoc::getFromDILocation(Loc));
 }
 
@@ -2195,7 +2253,7 @@ LLVMValueRef LLVMBuildMalloc(LLVMBuilderRef B, LLVMTypeRef Ty,
   AllocSize = ConstantExpr::getTruncOrBitCast(AllocSize, ITy);
   Instruction* Malloc = CallInst::CreateMalloc(unwrap(B)->GetInsertBlock(),
                                                ITy, unwrap(Ty), AllocSize,
-                                               0, 0, "");
+                                               nullptr, nullptr, "");
   return wrap(unwrap(B)->Insert(Malloc, Twine(Name)));
 }
 
@@ -2206,13 +2264,13 @@ LLVMValueRef LLVMBuildArrayMalloc(LLVMBuilderRef B, LLVMTypeRef Ty,
   AllocSize = ConstantExpr::getTruncOrBitCast(AllocSize, ITy);
   Instruction* Malloc = CallInst::CreateMalloc(unwrap(B)->GetInsertBlock(),
                                                ITy, unwrap(Ty), AllocSize,
-                                               unwrap(Val), 0, "");
+                                               unwrap(Val), nullptr, "");
   return wrap(unwrap(B)->Insert(Malloc, Twine(Name)));
 }
 
 LLVMValueRef LLVMBuildAlloca(LLVMBuilderRef B, LLVMTypeRef Ty,
                              const char *Name) {
-  return wrap(unwrap(B)->CreateAlloca(unwrap(Ty), 0, Name));
+  return wrap(unwrap(B)->CreateAlloca(unwrap(Ty), nullptr, Name));
 }
 
 LLVMValueRef LLVMBuildArrayAlloca(LLVMBuilderRef B, LLVMTypeRef Ty,
diff --git a/lib/IR/DIBuilder.cpp b/lib/IR/DIBuilder.cpp
index 1ea381a..92edacc 100644
--- a/lib/IR/DIBuilder.cpp
+++ b/lib/IR/DIBuilder.cpp
@@ -30,8 +30,9 @@ static Constant *GetTagConstant(LLVMContext &VMContext, unsigned Tag) {
 }
 
 DIBuilder::DIBuilder(Module &m)
-    : M(m), VMContext(M.getContext()), TempEnumTypes(0), TempRetainTypes(0),
-      TempSubprograms(0), TempGVs(0), DeclareFn(0), ValueFn(0) {}
+    : M(m), VMContext(M.getContext()), TempEnumTypes(nullptr),
+      TempRetainTypes(nullptr), TempSubprograms(nullptr), TempGVs(nullptr),
+      DeclareFn(nullptr), ValueFn(nullptr) {}
 
 /// finalize - Construct any deferred debug info descriptors.
 void DIBuilder::finalize() {
@@ -80,7 +81,7 @@ void DIBuilder::finalize() {
 /// N.
 static MDNode *getNonCompileUnitScope(MDNode *N) {
   if (DIDescriptor(N).isCompileUnit())
-    return NULL;
+    return nullptr;
   return N;
 }
 
@@ -103,7 +104,7 @@ DICompileUnit DIBuilder::createCompileUnit(unsigned Lang, StringRef Filename,
                                            StringRef SplitName,
                                            DebugEmissionKind Kind) {
 
-  assert(((Lang <= dwarf::DW_LANG_Python && Lang >= dwarf::DW_LANG_C89) ||
+  assert(((Lang <= dwarf::DW_LANG_OCaml && Lang >= dwarf::DW_LANG_C89) ||
           (Lang <= dwarf::DW_LANG_hi_user && Lang >= dwarf::DW_LANG_lo_user)) &&
          "Invalid Language tag");
   assert(!Filename.empty() &&
@@ -146,13 +147,13 @@ DICompileUnit DIBuilder::createCompileUnit(unsigned Lang, StringRef Filename,
 }
 
 static DIImportedEntity
-createImportedModule(LLVMContext &C, DIScope Context, DIDescriptor NS,
-                     unsigned Line, StringRef Name,
-                     SmallVectorImpl<TrackingVH<MDNode> > &AllImportedModules) {
+createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope Context,
+                     Value *NS, unsigned Line, StringRef Name,
+                     SmallVectorImpl<TrackingVH<MDNode>> &AllImportedModules) {
   const MDNode *R;
   if (Name.empty()) {
     Value *Elts[] = {
-      GetTagConstant(C, dwarf::DW_TAG_imported_module),
+      GetTagConstant(C, Tag),
       Context,
       NS,
       ConstantInt::get(Type::getInt32Ty(C), Line),
@@ -160,7 +161,7 @@ createImportedModule(LLVMContext &C, DIScope Context, DIDescriptor NS,
     R = MDNode::get(C, Elts);
   } else {
     Value *Elts[] = {
-      GetTagConstant(C, dwarf::DW_TAG_imported_module),
+      GetTagConstant(C, Tag),
       Context,
       NS,
       ConstantInt::get(Type::getInt32Ty(C), Line),
@@ -175,33 +176,32 @@ createImportedModule(LLVMContext &C, DIScope Context, DIDescriptor NS,
 }
 
 DIImportedEntity DIBuilder::createImportedModule(DIScope Context,
-                                                 DINameSpace NS, unsigned Line,
-                                                 StringRef Name) {
-  return ::createImportedModule(VMContext, Context, NS, Line, Name,
-                                AllImportedModules);
+                                                 DINameSpace NS,
+                                                 unsigned Line) {
+  return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
+                                Context, NS, Line, StringRef(), AllImportedModules);
 }
 
 DIImportedEntity DIBuilder::createImportedModule(DIScope Context,
                                                  DIImportedEntity NS,
-                                                 unsigned Line,
-                                                 StringRef Name) {
-  return ::createImportedModule(VMContext, Context, NS, Line, Name,
-                                AllImportedModules);
+                                                 unsigned Line) {
+  return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
+                                Context, NS, Line, StringRef(), AllImportedModules);
 }
 
 DIImportedEntity DIBuilder::createImportedDeclaration(DIScope Context,
                                                       DIScope Decl,
-                                                      unsigned Line) {
-  Value *Elts[] = {
-    GetTagConstant(VMContext, dwarf::DW_TAG_imported_declaration),
-    Context,
-    Decl.getRef(),
-    ConstantInt::get(Type::getInt32Ty(VMContext), Line),
-  };
-  DIImportedEntity M(MDNode::get(VMContext, Elts));
-  assert(M.Verify() && "Imported module should be valid");
-  AllImportedModules.push_back(TrackingVH<MDNode>(M));
-  return M;
+                                                      unsigned Line, StringRef Name) {
+  return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_declaration,
+                                Context, Decl.getRef(), Line, Name,
+                                AllImportedModules);
+}
+
+DIImportedEntity DIBuilder::createImportedDeclaration(DIScope Context,
+                                                      DIImportedEntity Imp,
+                                                      unsigned Line, StringRef Name) {
+  return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_declaration,
+                                Context, Imp, Line, Name, AllImportedModules);
 }
 
 /// createFile - Create a file descriptor to hold debugging information
@@ -232,8 +232,8 @@ DIBasicType DIBuilder::createUnspecifiedType(StringRef Name) {
   // size, alignment, offset and flags are always empty here.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_unspecified_type),
-    NULL, // Filename
-    NULL, // Unused
+    nullptr, // Filename
+    nullptr, // Unused
     MDString::get(VMContext, Name),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
@@ -260,8 +260,8 @@ DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
   // offset and flags are always empty here.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_base_type),
-    NULL, // File/directory name
-    NULL, // Unused
+    nullptr, // File/directory name
+    nullptr, // Unused
     MDString::get(VMContext, Name),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), SizeInBits),
@@ -279,8 +279,8 @@ DIDerivedType DIBuilder::createQualifiedType(unsigned Tag, DIType FromTy) {
   // Qualified types are encoded in DIDerivedType format.
   Value *Elts[] = {
     GetTagConstant(VMContext, Tag),
-    NULL, // Filename
-    NULL, // Unused
+    nullptr, // Filename
+    nullptr, // Unused
     MDString::get(VMContext, StringRef()), // Empty name.
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
@@ -299,8 +299,8 @@ DIBuilder::createPointerType(DIType PointeeTy, uint64_t SizeInBits,
   // Pointer types are encoded in DIDerivedType format.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_pointer_type),
-    NULL, // Filename
-    NULL, // Unused
+    nullptr, // Filename
+    nullptr, // Unused
     MDString::get(VMContext, Name),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), SizeInBits),
@@ -317,9 +317,9 @@ DIDerivedType DIBuilder::createMemberPointerType(DIType PointeeTy,
   // Pointer types are encoded in DIDerivedType format.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_ptr_to_member_type),
-    NULL, // Filename
-    NULL, // Unused
-    NULL,
+    nullptr, // Filename
+    nullptr, // Unused
+    nullptr,
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Align
@@ -338,9 +338,9 @@ DIDerivedType DIBuilder::createReferenceType(unsigned Tag, DIType RTy) {
   // References are encoded in DIDerivedType format.
   Value *Elts[] = {
     GetTagConstant(VMContext, Tag),
-    NULL, // Filename
-    NULL, // TheCU,
-    NULL, // Name
+    nullptr, // Filename
+    nullptr, // TheCU,
+    nullptr, // Name
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Align
@@ -355,7 +355,6 @@ DIDerivedType DIBuilder::createReferenceType(unsigned Tag, DIType RTy) {
 DIDerivedType DIBuilder::createTypedef(DIType Ty, StringRef Name, DIFile File,
                                        unsigned LineNo, DIDescriptor Context) {
   // typedefs are encoded in DIDerivedType format.
-  assert(Ty.isType() && "Invalid typedef type!");
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_typedef),
     File.getFileNode(),
@@ -378,9 +377,9 @@ DIDerivedType DIBuilder::createFriend(DIType Ty, DIType FriendTy) {
   assert(FriendTy.isType() && "Invalid friend type!");
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_friend),
-    NULL,
+    nullptr,
     Ty.getRef(),
-    NULL, // Name
+    nullptr, // Name
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Align
@@ -400,9 +399,9 @@ DIDerivedType DIBuilder::createInheritance(DIType Ty, DIType BaseTy,
   // TAG_inheritance is encoded in DIDerivedType format.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_inheritance),
-    NULL,
+    nullptr,
     Ty.getRef(),
-    NULL, // Name
+    nullptr, // Name
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Align
@@ -631,7 +630,8 @@ DICompositeType DIBuilder::createClassType(DIDescriptor Context, StringRef Name,
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
     VTableHolder.getRef(),
     TemplateParams,
-    UniqueIdentifier.empty() ? NULL : MDString::get(VMContext, UniqueIdentifier)
+    UniqueIdentifier.empty() ? nullptr
+                             : MDString::get(VMContext, UniqueIdentifier)
   };
   DICompositeType R(MDNode::get(VMContext, Elts));
   assert(R.isCompositeType() &&
@@ -667,8 +667,9 @@ DICompositeType DIBuilder::createStructType(DIDescriptor Context,
     Elements,
     ConstantInt::get(Type::getInt32Ty(VMContext), RunTimeLang),
     VTableHolder.getRef(),
-    NULL,
-    UniqueIdentifier.empty() ? NULL : MDString::get(VMContext, UniqueIdentifier)
+    nullptr,
+    UniqueIdentifier.empty() ? nullptr
+                             : MDString::get(VMContext, UniqueIdentifier)
   };
   DICompositeType R(MDNode::get(VMContext, Elts));
   assert(R.isCompositeType() &&
@@ -697,12 +698,13 @@ DICompositeType DIBuilder::createUnionType(DIDescriptor Scope, StringRef Name,
     ConstantInt::get(Type::getInt64Ty(VMContext), AlignInBits),
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Offset
     ConstantInt::get(Type::getInt32Ty(VMContext), Flags),
-    NULL,
+    nullptr,
     Elements,
     ConstantInt::get(Type::getInt32Ty(VMContext), RunTimeLang),
-    NULL,
-    NULL,
-    UniqueIdentifier.empty() ? NULL : MDString::get(VMContext, UniqueIdentifier)
+    nullptr,
+    nullptr,
+    UniqueIdentifier.empty() ? nullptr
+                             : MDString::get(VMContext, UniqueIdentifier)
   };
   DICompositeType R(MDNode::get(VMContext, Elts));
   if (!UniqueIdentifier.empty())
@@ -718,19 +720,19 @@ DICompositeType DIBuilder::createSubroutineType(DIFile File,
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_subroutine_type),
     Constant::getNullValue(Type::getInt32Ty(VMContext)),
-    NULL,
+    nullptr,
     MDString::get(VMContext, ""),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Align
     ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Offset
     ConstantInt::get(Type::getInt32Ty(VMContext), Flags), // Flags
-    NULL,
+    nullptr,
     ParameterTypes,
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
-    NULL,
-    NULL,
-    NULL  // Type Identifer
+    nullptr,
+    nullptr,
+    nullptr  // Type Identifer
   };
   return DICompositeType(MDNode::get(VMContext, Elts));
 }
@@ -755,9 +757,10 @@ DICompositeType DIBuilder::createEnumerationType(
     UnderlyingType.getRef(),
     Elements,
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
-    NULL,
-    NULL,
-    UniqueIdentifier.empty() ? NULL : MDString::get(VMContext, UniqueIdentifier)
+    nullptr,
+    nullptr,
+    UniqueIdentifier.empty() ? nullptr
+                             : MDString::get(VMContext, UniqueIdentifier)
   };
   DICompositeType CTy(MDNode::get(VMContext, Elts));
   AllEnumTypes.push_back(CTy);
@@ -772,8 +775,8 @@ DICompositeType DIBuilder::createArrayType(uint64_t Size, uint64_t AlignInBits,
   // TAG_array_type is encoded in DICompositeType format.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_array_type),
-    NULL, // Filename/Directory,
-    NULL, // Unused
+    nullptr, // Filename/Directory,
+    nullptr, // Unused
     MDString::get(VMContext, ""),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), Size),
@@ -783,9 +786,9 @@ DICompositeType DIBuilder::createArrayType(uint64_t Size, uint64_t AlignInBits,
     Ty.getRef(),
     Subscripts,
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
-    NULL,
-    NULL,
-    NULL  // Type Identifer
+    nullptr,
+    nullptr,
+    nullptr  // Type Identifer
   };
   return DICompositeType(MDNode::get(VMContext, Elts));
 }
@@ -796,8 +799,8 @@ DICompositeType DIBuilder::createVectorType(uint64_t Size, uint64_t AlignInBits,
   // A vector is an array type with the FlagVector flag applied.
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_array_type),
-    NULL, // Filename/Directory,
-    NULL, // Unused
+    nullptr, // Filename/Directory,
+    nullptr, // Unused
     MDString::get(VMContext, ""),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
     ConstantInt::get(Type::getInt64Ty(VMContext), Size),
@@ -807,9 +810,9 @@ DICompositeType DIBuilder::createVectorType(uint64_t Size, uint64_t AlignInBits,
     Ty.getRef(),
     Subscripts,
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
-    NULL,
-    NULL,
-    NULL  // Type Identifer
+    nullptr,
+    nullptr,
+    nullptr  // Type Identifer
   };
   return DICompositeType(MDNode::get(VMContext, Elts));
 }
@@ -890,12 +893,47 @@ DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIDescriptor Scope,
     ConstantInt::get(Type::getInt64Ty(VMContext), AlignInBits),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Offset
     ConstantInt::get(Type::getInt32Ty(VMContext), DIDescriptor::FlagFwdDecl),
-    NULL,
+    nullptr,
+    DIArray(),
+    ConstantInt::get(Type::getInt32Ty(VMContext), RuntimeLang),
+    nullptr,
+    nullptr, //TemplateParams
+    UniqueIdentifier.empty() ? nullptr
+                             : MDString::get(VMContext, UniqueIdentifier)
+  };
+  MDNode *Node = MDNode::get(VMContext, Elts);
+  DICompositeType RetTy(Node);
+  assert(RetTy.isCompositeType() &&
+         "createForwardDecl result should be a DIType");
+  if (!UniqueIdentifier.empty())
+    retainType(RetTy);
+  return RetTy;
+}
+
+/// createForwardDecl - Create a temporary forward-declared type that
+/// can be RAUW'd if the full type is seen.
+DICompositeType DIBuilder::createReplaceableForwardDecl(
+    unsigned Tag, StringRef Name, DIDescriptor Scope, DIFile F, unsigned Line,
+    unsigned RuntimeLang, uint64_t SizeInBits, uint64_t AlignInBits,
+    StringRef UniqueIdentifier) {
+  // Create a temporary MDNode.
+  Value *Elts[] = {
+    GetTagConstant(VMContext, Tag),
+    F.getFileNode(),
+    DIScope(getNonCompileUnitScope(Scope)).getRef(),
+    MDString::get(VMContext, Name),
+    ConstantInt::get(Type::getInt32Ty(VMContext), Line),
+    ConstantInt::get(Type::getInt64Ty(VMContext), SizeInBits),
+    ConstantInt::get(Type::getInt64Ty(VMContext), AlignInBits),
+    ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Offset
+    ConstantInt::get(Type::getInt32Ty(VMContext), DIDescriptor::FlagFwdDecl),
+    nullptr,
     DIArray(),
     ConstantInt::get(Type::getInt32Ty(VMContext), RuntimeLang),
-    NULL,
-    NULL, //TemplateParams
-    UniqueIdentifier.empty() ? NULL : MDString::get(VMContext, UniqueIdentifier)
+    nullptr,
+    nullptr, //TemplateParams
+    UniqueIdentifier.empty() ? nullptr
+                             : MDString::get(VMContext, UniqueIdentifier)
   };
   MDNode *Node = MDNode::getTemporary(VMContext, Elts);
   DICompositeType RetTy(Node);
@@ -932,7 +970,7 @@ DIGlobalVariable DIBuilder::createGlobalVariable(StringRef Name,
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_variable),
     Constant::getNullValue(Type::getInt32Ty(VMContext)),
-    NULL, // TheCU,
+    nullptr, // TheCU,
     MDString::get(VMContext, Name),
     MDString::get(VMContext, Name),
     MDString::get(VMContext, LinkageName),
@@ -1087,7 +1125,7 @@ DISubprogram DIBuilder::createFunction(DIDescriptor Context, StringRef Name,
     ConstantInt::get(Type::getInt1Ty(VMContext), isDefinition),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
     ConstantInt::get(Type::getInt32Ty(VMContext), 0),
-    NULL,
+    nullptr,
     ConstantInt::get(Type::getInt32Ty(VMContext), Flags),
     ConstantInt::get(Type::getInt1Ty(VMContext), isOptimized),
     Fn,
@@ -1121,7 +1159,6 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context, StringRef Name,
   assert(getNonCompileUnitScope(Context) &&
          "Methods should have both a Context and a context that isn't "
          "the compile unit.");
-  Value *TElts[] = { GetTagConstant(VMContext, DW_TAG_base_type) };
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_subprogram),
     F.getFileNode(),
@@ -1141,7 +1178,7 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context, StringRef Name,
     Fn,
     TParam,
     Constant::getNullValue(Type::getInt32Ty(VMContext)),
-    MDNode::getTemporary(VMContext, TElts),
+    nullptr,
     // FIXME: Do we want to use different scope/lines?
     ConstantInt::get(Type::getInt32Ty(VMContext), LineNo)
   };
@@ -1189,6 +1226,13 @@ DILexicalBlockFile DIBuilder::createLexicalBlockFile(DIDescriptor Scope,
 DILexicalBlock DIBuilder::createLexicalBlock(DIDescriptor Scope, DIFile File,
                                              unsigned Line, unsigned Col,
                                              unsigned Discriminator) {
+  // FIXME: This isn't thread safe nor the right way to defeat MDNode uniquing.
+  // I believe the right way is to have a self-referential element in the node.
+  // Also: why do we bother with line/column - they're not used and the
+  // documentation (SourceLevelDebugging.rst) claims the line/col are necessary
+  // for uniquing, yet then we have this other solution (because line/col were
+  // inadequate) anyway. Remove all 3 and replace them with a self-reference.
+
   // Defeat MDNode uniquing for lexical blocks by using unique id.
   static unsigned int unique_id = 0;
   Value *Elts[] = {
diff --git a/lib/IR/DataLayout.cpp b/lib/IR/DataLayout.cpp
index 6c18387..dea05fb 100644
--- a/lib/IR/DataLayout.cpp
+++ b/lib/IR/DataLayout.cpp
@@ -178,7 +178,7 @@ static const LayoutAlignElem DefaultAlignments[] = {
 void DataLayout::reset(StringRef Desc) {
   clear();
 
-  LayoutMap = 0;
+  LayoutMap = nullptr;
   LittleEndian = false;
   StackNaturalAlign = 0;
   ManglingMode = MM_None;
@@ -344,7 +344,7 @@ void DataLayout::parseSpecifier(StringRef Desc) {
   }
 }
 
-DataLayout::DataLayout(const Module *M) : LayoutMap(0) {
+DataLayout::DataLayout(const Module *M) : LayoutMap(nullptr) {
   const DataLayout *Other = M->getDataLayout();
   if (Other)
     *this = *Other;
@@ -357,7 +357,7 @@ bool DataLayout::operator==(const DataLayout &Other) const {
              StackNaturalAlign == Other.StackNaturalAlign &&
              ManglingMode == Other.ManglingMode &&
              LegalIntWidths == Other.LegalIntWidths &&
-             Alignments == Other.Alignments && Pointers == Pointers;
+             Alignments == Other.Alignments && Pointers == Other.Pointers;
   assert(Ret == (getStringRepresentation() == Other.getStringRepresentation()));
   return Ret;
 }
@@ -488,7 +488,7 @@ void DataLayout::clear() {
   Alignments.clear();
   Pointers.clear();
   delete static_cast<StructLayoutMap *>(LayoutMap);
-  LayoutMap = 0;
+  LayoutMap = nullptr;
 }
 
 DataLayout::~DataLayout() {
@@ -687,7 +687,7 @@ unsigned DataLayout::getABITypeAlignment(Type *Ty) const {
 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
 /// an integer type of the specified bitwidth.
 unsigned DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
-  return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, 0);
+  return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, nullptr);
 }
 
 unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
@@ -708,7 +708,7 @@ IntegerType *DataLayout::getIntPtrType(LLVMContext &C,
 Type *DataLayout::getIntPtrType(Type *Ty) const {
   assert(Ty->isPtrOrPtrVectorTy() &&
          "Expected a pointer or pointer vector type.");
-  unsigned NumBits = getTypeSizeInBits(Ty->getScalarType());
+  unsigned NumBits = getPointerTypeSizeInBits(Ty);
   IntegerType *IntTy = IntegerType::get(Ty->getContext(), NumBits);
   if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
     return VectorType::get(IntTy, VecTy->getNumElements());
@@ -719,7 +719,7 @@ Type *DataLayout::getSmallestLegalIntType(LLVMContext &C, unsigned Width) const
   for (unsigned LegalIntWidth : LegalIntWidths)
     if (Width <= LegalIntWidth)
       return Type::getIntNTy(C, LegalIntWidth);
-  return 0;
+  return nullptr;
 }
 
 unsigned DataLayout::getLargestLegalIntTypeSize() const {
diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index c9d68af..db9e56d 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -53,8 +53,8 @@ bool DIDescriptor::Verify() const {
 }
 
 static Value *getField(const MDNode *DbgNode, unsigned Elt) {
-  if (DbgNode == 0 || Elt >= DbgNode->getNumOperands())
-    return 0;
+  if (!DbgNode || Elt >= DbgNode->getNumOperands())
+    return nullptr;
   return DbgNode->getOperand(Elt);
 }
 
@@ -73,7 +73,7 @@ StringRef DIDescriptor::getStringField(unsigned Elt) const {
 }
 
 uint64_t DIDescriptor::getUInt64Field(unsigned Elt) const {
-  if (DbgNode == 0)
+  if (!DbgNode)
     return 0;
 
   if (Elt < DbgNode->getNumOperands())
@@ -85,7 +85,7 @@ uint64_t DIDescriptor::getUInt64Field(unsigned Elt) const {
 }
 
 int64_t DIDescriptor::getInt64Field(unsigned Elt) const {
-  if (DbgNode == 0)
+  if (!DbgNode)
     return 0;
 
   if (Elt < DbgNode->getNumOperands())
@@ -102,34 +102,34 @@ DIDescriptor DIDescriptor::getDescriptorField(unsigned Elt) const {
 }
 
 GlobalVariable *DIDescriptor::getGlobalVariableField(unsigned Elt) const {
-  if (DbgNode == 0)
-    return 0;
+  if (!DbgNode)
+    return nullptr;
 
   if (Elt < DbgNode->getNumOperands())
     return dyn_cast_or_null<GlobalVariable>(DbgNode->getOperand(Elt));
-  return 0;
+  return nullptr;
 }
 
 Constant *DIDescriptor::getConstantField(unsigned Elt) const {
-  if (DbgNode == 0)
-    return 0;
+  if (!DbgNode)
+    return nullptr;
 
   if (Elt < DbgNode->getNumOperands())
     return dyn_cast_or_null<Constant>(DbgNode->getOperand(Elt));
-  return 0;
+  return nullptr;
 }
 
 Function *DIDescriptor::getFunctionField(unsigned Elt) const {
-  if (DbgNode == 0)
-    return 0;
+  if (!DbgNode)
+    return nullptr;
 
   if (Elt < DbgNode->getNumOperands())
     return dyn_cast_or_null<Function>(DbgNode->getOperand(Elt));
-  return 0;
+  return nullptr;
 }
 
 void DIDescriptor::replaceFunctionField(unsigned Elt, Function *F) {
-  if (DbgNode == 0)
+  if (!DbgNode)
     return;
 
   if (Elt < DbgNode->getNumOperands()) {
@@ -335,7 +335,7 @@ unsigned DIArray::getNumElements() const {
 
 /// replaceAllUsesWith - Replace all uses of the MDNode used by this
 /// type with the one in the passed descriptor.
-void DIType::replaceAllUsesWith(DIDescriptor &D) {
+void DIType::replaceAllUsesWith(LLVMContext &VMContext, DIDescriptor D) {
 
   assert(DbgNode && "Trying to replace an unverified type!");
 
@@ -344,13 +344,19 @@ void DIType::replaceAllUsesWith(DIDescriptor &D) {
   // which, due to uniquing, has merged with the source. We shield clients from
   // this detail by allowing a value to be replaced with replaceAllUsesWith()
   // itself.
-  if (DbgNode != D) {
-    MDNode *Node = const_cast<MDNode *>(DbgNode);
-    const MDNode *DN = D;
-    const Value *V = cast_or_null<Value>(DN);
-    Node->replaceAllUsesWith(const_cast<Value *>(V));
-    MDNode::deleteTemporary(Node);
+  const MDNode *DN = D;
+  if (DbgNode == DN) {
+    SmallVector<Value*, 10> Ops(DbgNode->getNumOperands());
+    for (size_t i = 0; i != Ops.size(); ++i)
+      Ops[i] = DbgNode->getOperand(i);
+    DN = MDNode::get(VMContext, Ops);
   }
+
+  MDNode *Node = const_cast<MDNode *>(DbgNode);
+  const Value *V = cast_or_null<Value>(DN);
+  Node->replaceAllUsesWith(const_cast<Value *>(V));
+  MDNode::deleteTemporary(Node);
+  DbgNode = D;
 }
 
 /// replaceAllUsesWith - Replace all uses of the MDNode used by this
@@ -358,19 +364,12 @@ void DIType::replaceAllUsesWith(DIDescriptor &D) {
 void DIType::replaceAllUsesWith(MDNode *D) {
 
   assert(DbgNode && "Trying to replace an unverified type!");
-
-  // Since we use a TrackingVH for the node, its easy for clients to manufacture
-  // legitimate situations where they want to replaceAllUsesWith() on something
-  // which, due to uniquing, has merged with the source. We shield clients from
-  // this detail by allowing a value to be replaced with replaceAllUsesWith()
-  // itself.
-  if (DbgNode != D) {
-    MDNode *Node = const_cast<MDNode *>(DbgNode);
-    const MDNode *DN = D;
-    const Value *V = cast_or_null<Value>(DN);
-    Node->replaceAllUsesWith(const_cast<Value *>(V));
-    MDNode::deleteTemporary(Node);
-  }
+  assert(DbgNode != D && "This replacement should always happen");
+  MDNode *Node = const_cast<MDNode *>(DbgNode);
+  const MDNode *DN = D;
+  const Value *V = cast_or_null<Value>(DN);
+  Node->replaceAllUsesWith(const_cast<Value *>(V));
+  MDNode::deleteTemporary(Node);
 }
 
 /// Verify - Verify that a compile unit is well formed.
@@ -759,7 +758,7 @@ DIScopeRef DIScope::getContext() const {
     return DIScopeRef(DINameSpace(DbgNode).getContext());
 
   assert((isFile() || isCompileUnit()) && "Unhandled type of scope.");
-  return DIScopeRef(NULL);
+  return DIScopeRef(nullptr);
 }
 
 // If the scope node has a name, return that, else return an empty string.
diff --git a/lib/IR/DebugLoc.cpp b/lib/IR/DebugLoc.cpp
index 1a2521e..43360d3 100644
--- a/lib/IR/DebugLoc.cpp
+++ b/lib/IR/DebugLoc.cpp
@@ -18,7 +18,7 @@ using namespace llvm;
 //===----------------------------------------------------------------------===//
 
 MDNode *DebugLoc::getScope(const LLVMContext &Ctx) const {
-  if (ScopeIdx == 0) return 0;
+  if (ScopeIdx == 0) return nullptr;
   
   if (ScopeIdx > 0) {
     // Positive ScopeIdx is an index into ScopeRecords, which has no inlined-at
@@ -37,7 +37,7 @@ MDNode *DebugLoc::getScope(const LLVMContext &Ctx) const {
 MDNode *DebugLoc::getInlinedAt(const LLVMContext &Ctx) const {
   // Positive ScopeIdx is an index into ScopeRecords, which has no inlined-at
   // position specified.  Zero is invalid.
-  if (ScopeIdx >= 0) return 0;
+  if (ScopeIdx >= 0) return nullptr;
   
   // Otherwise, the index is in the ScopeInlinedAtRecords array.
   assert(unsigned(-ScopeIdx) <= Ctx.pImpl->ScopeInlinedAtRecords.size() &&
@@ -49,7 +49,7 @@ MDNode *DebugLoc::getInlinedAt(const LLVMContext &Ctx) const {
 void DebugLoc::getScopeAndInlinedAt(MDNode *&Scope, MDNode *&IA,
                                     const LLVMContext &Ctx) const {
   if (ScopeIdx == 0) {
-    Scope = IA = 0;
+    Scope = IA = nullptr;
     return;
   }
   
@@ -59,7 +59,7 @@ void DebugLoc::getScopeAndInlinedAt(MDNode *&Scope, MDNode *&IA,
     assert(unsigned(ScopeIdx) <= Ctx.pImpl->ScopeRecords.size() &&
            "Invalid ScopeIdx!");
     Scope = Ctx.pImpl->ScopeRecords[ScopeIdx-1].get();
-    IA = 0;
+    IA = nullptr;
     return;
   }
   
@@ -96,8 +96,8 @@ DebugLoc DebugLoc::get(unsigned Line, unsigned Col,
   DebugLoc Result;
   
   // If no scope is available, this is an unknown location.
-  if (Scope == 0) return Result;
-  
+  if (!Scope) return Result;
+
   // Saturate line and col to "unknown".
   if (Col > 255) Col = 0;
   if (Line >= (1 << 24)) Line = 0;
@@ -106,7 +106,7 @@ DebugLoc DebugLoc::get(unsigned Line, unsigned Col,
   LLVMContext &Ctx = Scope->getContext();
   
   // If there is no inlined-at location, use the ScopeRecords array.
-  if (InlinedAt == 0)
+  if (!InlinedAt)
     Result.ScopeIdx = Ctx.pImpl->getOrAddScopeRecordIdxEntry(Scope, 0);
   else
     Result.ScopeIdx = Ctx.pImpl->getOrAddScopeInlinedAtIdxEntry(Scope,
@@ -118,7 +118,7 @@ DebugLoc DebugLoc::get(unsigned Line, unsigned Col,
 /// getAsMDNode - This method converts the compressed DebugLoc node into a
 /// DILocation-compatible MDNode.
 MDNode *DebugLoc::getAsMDNode(const LLVMContext &Ctx) const {
-  if (isUnknown()) return 0;
+  if (isUnknown()) return nullptr;
   
   MDNode *Scope, *IA;
   getScopeAndInlinedAt(Scope, IA, Ctx);
@@ -137,7 +137,7 @@ MDNode *DebugLoc::getAsMDNode(const LLVMContext &Ctx) const {
 DebugLoc DebugLoc::getFromDILocation(MDNode *N) {
   DILocation Loc(N);
   MDNode *Scope = Loc.getScope();
-  if (Scope == 0) return DebugLoc();
+  if (!Scope) return DebugLoc();
   return get(Loc.getLineNumber(), Loc.getColumnNumber(), Scope,
              Loc.getOrigLocation());
 }
@@ -146,8 +146,9 @@ DebugLoc DebugLoc::getFromDILocation(MDNode *N) {
 DebugLoc DebugLoc::getFromDILexicalBlock(MDNode *N) {
   DILexicalBlock LexBlock(N);
   MDNode *Scope = LexBlock.getContext();
-  if (Scope == 0) return DebugLoc();
-  return get(LexBlock.getLineNumber(), LexBlock.getColumnNumber(), Scope, NULL);
+  if (!Scope) return DebugLoc();
+  return get(LexBlock.getLineNumber(), LexBlock.getColumnNumber(), Scope,
+             nullptr);
 }
 
 void DebugLoc::dump(const LLVMContext &Ctx) const {
@@ -166,6 +167,28 @@ void DebugLoc::dump(const LLVMContext &Ctx) const {
 #endif
 }
 
+void DebugLoc::print(const LLVMContext &Ctx, raw_ostream &OS) const {
+  if (!isUnknown()) {
+    // Print source line info.
+    DIScope Scope(getScope(Ctx));
+    assert((!Scope || Scope.isScope()) &&
+           "Scope of a DebugLoc should be null or a DIScope.");
+    if (Scope)
+      OS << Scope.getFilename();
+    else
+      OS << "<unknown>";
+    OS << ':' << getLine();
+    if (getCol() != 0)
+      OS << ':' << getCol();
+    DebugLoc InlinedAtDL = DebugLoc::getFromDILocation(getInlinedAt(Ctx));
+    if (!InlinedAtDL.isUnknown()) {
+      OS << " @[ ";
+      InlinedAtDL.print(Ctx, OS);
+      OS << " ]";
+    }
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // DenseMap specialization
 //===----------------------------------------------------------------------===//
@@ -234,7 +257,7 @@ void DebugRecVH::deleted() {
   // If this is a non-canonical reference, just drop the value to null, we know
   // it doesn't have a map entry.
   if (Idx == 0) {
-    setValPtr(0);
+    setValPtr(nullptr);
     return;
   }
     
@@ -245,7 +268,7 @@ void DebugRecVH::deleted() {
     assert(Ctx->ScopeRecordIdx[Cur] == Idx && "Mapping out of date!");
     Ctx->ScopeRecordIdx.erase(Cur);
     // Reset this VH to null and we're done.
-    setValPtr(0);
+    setValPtr(nullptr);
     Idx = 0;
     return;
   }
@@ -259,7 +282,7 @@ void DebugRecVH::deleted() {
   
   MDNode *OldScope = Entry.first.get();
   MDNode *OldInlinedAt = Entry.second.get();
-  assert(OldScope != 0 && OldInlinedAt != 0 &&
+  assert(OldScope && OldInlinedAt &&
          "Entry should be non-canonical if either val dropped to null");
 
   // Otherwise, we do have an entry in it, nuke it and we're done.
@@ -269,7 +292,7 @@ void DebugRecVH::deleted() {
   
   // Reset this VH to null.  Drop both 'Idx' values to null to indicate that
   // we're in non-canonical form now.
-  setValPtr(0);
+  setValPtr(nullptr);
   Entry.first.Idx = Entry.second.Idx = 0;
 }
 
@@ -277,8 +300,8 @@ void DebugRecVH::allUsesReplacedWith(Value *NewVa) {
   // If being replaced with a non-mdnode value (e.g. undef) handle this as if
   // the mdnode got deleted.
   MDNode *NewVal = dyn_cast<MDNode>(NewVa);
-  if (NewVal == 0) return deleted();
-  
+  if (!NewVal) return deleted();
+
   // If this is a non-canonical reference, just change it, we know it already
   // doesn't have a map entry.
   if (Idx == 0) {
@@ -313,7 +336,7 @@ void DebugRecVH::allUsesReplacedWith(Value *NewVa) {
   
   MDNode *OldScope = Entry.first.get();
   MDNode *OldInlinedAt = Entry.second.get();
-  assert(OldScope != 0 && OldInlinedAt != 0 &&
+  assert(OldScope && OldInlinedAt &&
          "Entry should be non-canonical if either val dropped to null");
   
   // Otherwise, we do have an entry in it, nuke it and we're done.
diff --git a/lib/IR/DiagnosticInfo.cpp b/lib/IR/DiagnosticInfo.cpp
index d59d4cf..6eeb162 100644
--- a/lib/IR/DiagnosticInfo.cpp
+++ b/lib/IR/DiagnosticInfo.cpp
@@ -12,18 +12,80 @@
 // Diagnostics reporting is still done as part of the LLVMContext.
 //===----------------------------------------------------------------------===//
 
+#include "LLVMContextImpl.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
 #include "llvm/Support/Atomic.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Regex.h"
 #include <string>
 
 using namespace llvm;
 
+namespace {
+
+/// \brief Regular expression corresponding to the value given in one of the
+/// -pass-remarks* command line flags. Passes whose name matches this regexp
+/// will emit a diagnostic when calling the associated diagnostic function
+/// (emitOptimizationRemark, emitOptimizationRemarkMissed or
+/// emitOptimizationRemarkAnalysis).
+struct PassRemarksOpt {
+  std::shared_ptr<Regex> Pattern;
+
+  void operator=(const std::string &Val) {
+    // Create a regexp object to match pass names for emitOptimizationRemark.
+    if (!Val.empty()) {
+      Pattern = std::make_shared<Regex>(Val);
+      std::string RegexError;
+      if (!Pattern->isValid(RegexError))
+        report_fatal_error("Invalid regular expression '" + Val +
+                               "' in -pass-remarks: " + RegexError,
+                           false);
+    }
+  };
+};
+
+static PassRemarksOpt PassRemarksOptLoc;
+static PassRemarksOpt PassRemarksMissedOptLoc;
+static PassRemarksOpt PassRemarksAnalysisOptLoc;
+
+// -pass-remarks
+//    Command line flag to enable emitOptimizationRemark()
+static cl::opt<PassRemarksOpt, true, cl::parser<std::string>>
+PassRemarks("pass-remarks", cl::value_desc("pattern"),
+            cl::desc("Enable optimization remarks from passes whose name match "
+                     "the given regular expression"),
+            cl::Hidden, cl::location(PassRemarksOptLoc), cl::ValueRequired,
+            cl::ZeroOrMore);
+
+// -pass-remarks-missed
+//    Command line flag to enable emitOptimizationRemarkMissed()
+static cl::opt<PassRemarksOpt, true, cl::parser<std::string>> PassRemarksMissed(
+    "pass-remarks-missed", cl::value_desc("pattern"),
+    cl::desc("Enable missed optimization remarks from passes whose name match "
+             "the given regular expression"),
+    cl::Hidden, cl::location(PassRemarksMissedOptLoc), cl::ValueRequired,
+    cl::ZeroOrMore);
+
+// -pass-remarks-analysis
+//    Command line flag to enable emitOptimizationRemarkAnalysis()
+static cl::opt<PassRemarksOpt, true, cl::parser<std::string>>
+PassRemarksAnalysis(
+    "pass-remarks-analysis", cl::value_desc("pattern"),
+    cl::desc(
+        "Enable optimization analysis remarks from passes whose name match "
+        "the given regular expression"),
+    cl::Hidden, cl::location(PassRemarksAnalysisOptLoc), cl::ValueRequired,
+    cl::ZeroOrMore);
+}
+
 int llvm::getNextAvailablePluginDiagnosticKind() {
   static sys::cas_flag PluginKindID = DK_FirstPluginKind;
   return (int)sys::AtomicIncrement(&PluginKindID);
@@ -64,3 +126,66 @@ void DiagnosticInfoSampleProfile::print(DiagnosticPrinter &DP) const {
     DP << getFileName() << ": ";
   DP << getMsg();
 }
+
+bool DiagnosticInfoOptimizationRemarkBase::isLocationAvailable() const {
+  return getFunction().getParent()->getNamedMetadata("llvm.dbg.cu") != nullptr;
+}
+
+void DiagnosticInfoOptimizationRemarkBase::getLocation(StringRef *Filename,
+                                                       unsigned *Line,
+                                                       unsigned *Column) const {
+  DILocation DIL(getDebugLoc().getAsMDNode(getFunction().getContext()));
+  *Filename = DIL.getFilename();
+  *Line = DIL.getLineNumber();
+  *Column = DIL.getColumnNumber();
+}
+
+const std::string DiagnosticInfoOptimizationRemarkBase::getLocationStr() const {
+  StringRef Filename("<unknown>");
+  unsigned Line = 0;
+  unsigned Column = 0;
+  if (isLocationAvailable())
+    getLocation(&Filename, &Line, &Column);
+  return Twine(Filename + ":" + Twine(Line) + ":" + Twine(Column)).str();
+}
+
+void DiagnosticInfoOptimizationRemarkBase::print(DiagnosticPrinter &DP) const {
+  DP << getLocationStr() << ": " << getMsg();
+}
+
+bool DiagnosticInfoOptimizationRemark::isEnabled() const {
+  return PassRemarksOptLoc.Pattern &&
+         PassRemarksOptLoc.Pattern->match(getPassName());
+}
+
+bool DiagnosticInfoOptimizationRemarkMissed::isEnabled() const {
+  return PassRemarksMissedOptLoc.Pattern &&
+         PassRemarksMissedOptLoc.Pattern->match(getPassName());
+}
+
+bool DiagnosticInfoOptimizationRemarkAnalysis::isEnabled() const {
+  return PassRemarksAnalysisOptLoc.Pattern &&
+         PassRemarksAnalysisOptLoc.Pattern->match(getPassName());
+}
+
+void llvm::emitOptimizationRemark(LLVMContext &Ctx, const char *PassName,
+                                  const Function &Fn, const DebugLoc &DLoc,
+                                  const Twine &Msg) {
+  Ctx.diagnose(DiagnosticInfoOptimizationRemark(PassName, Fn, DLoc, Msg));
+}
+
+void llvm::emitOptimizationRemarkMissed(LLVMContext &Ctx, const char *PassName,
+                                        const Function &Fn,
+                                        const DebugLoc &DLoc,
+                                        const Twine &Msg) {
+  Ctx.diagnose(DiagnosticInfoOptimizationRemarkMissed(PassName, Fn, DLoc, Msg));
+}
+
+void llvm::emitOptimizationRemarkAnalysis(LLVMContext &Ctx,
+                                          const char *PassName,
+                                          const Function &Fn,
+                                          const DebugLoc &DLoc,
+                                          const Twine &Msg) {
+  Ctx.diagnose(
+      DiagnosticInfoOptimizationRemarkAnalysis(PassName, Fn, DLoc, Msg));
+}
diff --git a/lib/IR/Function.cpp b/lib/IR/Function.cpp
index c2ea0e1..fe32c46 100644
--- a/lib/IR/Function.cpp
+++ b/lib/IR/Function.cpp
@@ -44,7 +44,7 @@ void Argument::anchor() { }
 
 Argument::Argument(Type *Ty, const Twine &Name, Function *Par)
   : Value(Ty, Value::ArgumentVal) {
-  Parent = 0;
+  Parent = nullptr;
 
   // Make sure that we get added to a function
   LeakDetector::addGarbageObject(this);
@@ -76,6 +76,14 @@ unsigned Argument::getArgNo() const {
   return ArgIdx;
 }
 
+/// hasNonNullAttr - Return true if this argument has the nonnull attribute on
+/// it in its containing function.
+bool Argument::hasNonNullAttr() const {
+  if (!getType()->isPointerTy()) return false;
+  return getParent()->getAttributes().
+    hasAttribute(getArgNo()+1, Attribute::NonNull);
+}
+
 /// hasByValAttr - Return true if this argument has the byval attribute on it
 /// in its containing function.
 bool Argument::hasByValAttr() const {
@@ -209,8 +217,8 @@ void Function::eraseFromParent() {
 
 Function::Function(FunctionType *Ty, LinkageTypes Linkage,
                    const Twine &name, Module *ParentModule)
-  : GlobalValue(PointerType::getUnqual(Ty),
-                Value::FunctionVal, 0, 0, Linkage, name) {
+  : GlobalObject(PointerType::getUnqual(Ty),
+                Value::FunctionVal, nullptr, 0, Linkage, name) {
   assert(FunctionType::isValidReturnType(getReturnType()) &&
          "invalid return type");
   SymTab = new ValueSymbolTable();
@@ -293,7 +301,7 @@ void Function::dropAllReferences() {
     BasicBlocks.begin()->eraseFromParent();
 
   // Prefix data is stored in a side table.
-  setPrefixData(0);
+  setPrefixData(nullptr);
 }
 
 void Function::addAttribute(unsigned i, Attribute::AttrKind attr) {
@@ -348,10 +356,10 @@ void Function::clearGC() {
     GCNames->erase(this);
     if (GCNames->empty()) {
       delete GCNames;
-      GCNames = 0;
+      GCNames = nullptr;
       if (GCNamePool->empty()) {
         delete GCNamePool;
-        GCNamePool = 0;
+        GCNamePool = nullptr;
       }
     }
   }
@@ -361,7 +369,7 @@ void Function::clearGC() {
 /// create a Function) from the Function Src to this one.
 void Function::copyAttributesFrom(const GlobalValue *Src) {
   assert(isa<Function>(Src) && "Expected a Function!");
-  GlobalValue::copyAttributesFrom(Src);
+  GlobalObject::copyAttributesFrom(Src);
   const Function *SrcF = cast<Function>(Src);
   setCallingConv(SrcF->getCallingConv());
   setAttributes(SrcF->getAttributes());
@@ -372,7 +380,7 @@ void Function::copyAttributesFrom(const GlobalValue *Src) {
   if (SrcF->hasPrefixData())
     setPrefixData(SrcF->getPrefixData());
   else
-    setPrefixData(0);
+    setPrefixData(nullptr);
 }
 
 /// getIntrinsicID - This method returns the ID number of the specified
diff --git a/lib/IR/GCOV.cpp b/lib/IR/GCOV.cpp
index f69bdc4..f2099d6 100644
--- a/lib/IR/GCOV.cpp
+++ b/lib/IR/GCOV.cpp
@@ -26,11 +26,6 @@ using namespace llvm;
 //===----------------------------------------------------------------------===//
 // GCOVFile implementation.
 
-/// ~GCOVFile - Delete GCOVFile and its content.
-GCOVFile::~GCOVFile() {
-  DeleteContainerPointers(Functions);
-}
-
 /// readGCNO - Read GCNO buffer.
 bool GCOVFile::readGCNO(GCOVBuffer &Buffer) {
   if (!Buffer.readGCNOFormat()) return false;
@@ -39,10 +34,10 @@ bool GCOVFile::readGCNO(GCOVBuffer &Buffer) {
   if (!Buffer.readInt(Checksum)) return false;
   while (true) {
     if (!Buffer.readFunctionTag()) break;
-    GCOVFunction *GFun = new GCOVFunction(*this);
+    auto GFun = make_unique<GCOVFunction>(*this);
     if (!GFun->readGCNO(Buffer, Version))
       return false;
-    Functions.push_back(GFun);
+    Functions.push_back(std::move(GFun));
   }
 
   GCNOInitialized = true;
@@ -97,17 +92,15 @@ bool GCOVFile::readGCDA(GCOVBuffer &Buffer) {
 
 /// dump - Dump GCOVFile content to dbgs() for debugging purposes.
 void GCOVFile::dump() const {
-  for (SmallVectorImpl<GCOVFunction *>::const_iterator I = Functions.begin(),
-         E = Functions.end(); I != E; ++I)
-    (*I)->dump();
+  for (const auto &FPtr : Functions)
+    FPtr->dump();
 }
 
 /// collectLineCounts - Collect line counts. This must be used after
 /// reading .gcno and .gcda files.
 void GCOVFile::collectLineCounts(FileInfo &FI) {
-  for (SmallVectorImpl<GCOVFunction *>::iterator I = Functions.begin(),
-         E = Functions.end(); I != E; ++I)
-    (*I)->collectLineCounts(FI);
+  for (const auto &FPtr : Functions)
+    FPtr->collectLineCounts(FI);
   FI.setRunCount(RunCount);
   FI.setProgramCount(ProgramCount);
 }
@@ -115,12 +108,6 @@ void GCOVFile::collectLineCounts(FileInfo &FI) {
 //===----------------------------------------------------------------------===//
 // GCOVFunction implementation.
 
-/// ~GCOVFunction - Delete GCOVFunction and its content.
-GCOVFunction::~GCOVFunction() {
-  DeleteContainerPointers(Blocks);
-  DeleteContainerPointers(Edges);
-}
-
 /// readGCNO - Read a function from the GCNO buffer. Return false if an error
 /// occurs.
 bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
@@ -150,7 +137,7 @@ bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
   if (!Buff.readInt(BlockCount)) return false;
   for (uint32_t i = 0, e = BlockCount; i != e; ++i) {
     if (!Buff.readInt(Dummy)) return false; // Block flags;
-    Blocks.push_back(new GCOVBlock(*this, i));
+    Blocks.push_back(make_unique<GCOVBlock>(*this, i));
   }
 
   // read edges.
@@ -168,8 +155,8 @@ bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
     for (uint32_t i = 0, e = EdgeCount; i != e; ++i) {
       uint32_t Dst;
       if (!Buff.readInt(Dst)) return false;
-      GCOVEdge *Edge = new GCOVEdge(Blocks[BlockNo], Blocks[Dst]);
-      Edges.push_back(Edge);
+      Edges.push_back(make_unique<GCOVEdge>(*Blocks[BlockNo], *Blocks[Dst]));
+      GCOVEdge *Edge = Edges.back().get();
       Blocks[BlockNo]->addDstEdge(Edge);
       Blocks[Dst]->addSrcEdge(Edge);
       if (!Buff.readInt(Dummy)) return false; // Edge flag
@@ -179,34 +166,46 @@ bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
   // read line table.
   while (Buff.readLineTag()) {
     uint32_t LineTableLength;
+    // Read the length of this line table.
     if (!Buff.readInt(LineTableLength)) return false;
     uint32_t EndPos = Buff.getCursor() + LineTableLength*4;
     uint32_t BlockNo;
+    // Read the block number this table is associated with.
     if (!Buff.readInt(BlockNo)) return false;
     if (BlockNo >= BlockCount) {
       errs() << "Unexpected block number: " << BlockNo << " (in " << Name
              << ").\n";
       return false;
     }
-    GCOVBlock *Block = Blocks[BlockNo];
-    if (!Buff.readInt(Dummy)) return false; // flag
-    while (Buff.getCursor() != (EndPos - 4)) {
+    GCOVBlock &Block = *Blocks[BlockNo];
+    // Read the word that pads the beginning of the line table. This may be a
+    // flag of some sort, but seems to always be zero.
+    if (!Buff.readInt(Dummy)) return false;
+
+    // Line information starts here and continues up until the last word.
+    if (Buff.getCursor() != (EndPos - sizeof(uint32_t))) {
       StringRef F;
+      // Read the source file name.
       if (!Buff.readString(F)) return false;
       if (Filename != F) {
         errs() << "Multiple sources for a single basic block: " << Filename
                << " != " << F << " (in " << Name << ").\n";
         return false;
       }
-      if (Buff.getCursor() == (EndPos - 4)) break;
-      while (true) {
+      // Read lines up to, but not including, the null terminator.
+      while (Buff.getCursor() < (EndPos - 2 * sizeof(uint32_t))) {
         uint32_t Line;
         if (!Buff.readInt(Line)) return false;
-        if (!Line) break;
-        Block->addLine(Line);
+        // Line 0 means this instruction was injected by the compiler. Skip it.
+        if (!Line) continue;
+        Block.addLine(Line);
       }
+      // Read the null terminator.
+      if (!Buff.readInt(Dummy)) return false;
     }
-    if (!Buff.readInt(Dummy)) return false; // flag
+    // The last word is either a flag or padding, it isn't clear which. Skip
+    // over it.
+    if (!Buff.readInt(Dummy)) return false;
   }
   return true;
 }
@@ -300,9 +299,8 @@ uint64_t GCOVFunction::getExitCount() const {
 /// dump - Dump GCOVFunction content to dbgs() for debugging purposes.
 void GCOVFunction::dump() const {
   dbgs() <<  "===== " << Name << " @ " << Filename << ":" << LineNumber << "\n";
-  for (SmallVectorImpl<GCOVBlock *>::const_iterator I = Blocks.begin(),
-         E = Blocks.end(); I != E; ++I)
-    (*I)->dump();
+  for (const auto &Block : Blocks)
+    Block->dump();
 }
 
 /// collectLineCounts - Collect line counts. This must be used after
@@ -313,9 +311,8 @@ void GCOVFunction::collectLineCounts(FileInfo &FI) {
   if (LineNumber == 0)
     return;
 
-  for (SmallVectorImpl<GCOVBlock *>::iterator I = Blocks.begin(),
-         E = Blocks.end(); I != E; ++I)
-    (*I)->collectLineCounts(FI);
+  for (const auto &Block : Blocks)
+    Block->collectLineCounts(FI);
   FI.addFunctionLine(Filename, LineNumber, this);
 }
 
@@ -335,8 +332,8 @@ void GCOVBlock::addCount(size_t DstEdgeNo, uint64_t N) {
   assert(DstEdgeNo < DstEdges.size()); // up to caller to ensure EdgeNo is valid
   DstEdges[DstEdgeNo]->Count = N;
   Counter += N;
-  if (!DstEdges[DstEdgeNo]->Dst->getNumDstEdges())
-    DstEdges[DstEdgeNo]->Dst->Counter += N;
+  if (!DstEdges[DstEdgeNo]->Dst.getNumDstEdges())
+    DstEdges[DstEdgeNo]->Dst.Counter += N;
 }
 
 /// sortDstEdges - Sort destination edges by block number, nop if already
@@ -363,7 +360,7 @@ void GCOVBlock::dump() const {
     dbgs() << "\tSource Edges : ";
     for (EdgeIterator I = SrcEdges.begin(), E = SrcEdges.end(); I != E; ++I) {
       const GCOVEdge *Edge = *I;
-      dbgs() << Edge->Src->Number << " (" << Edge->Count << "), ";
+      dbgs() << Edge->Src.Number << " (" << Edge->Count << "), ";
     }
     dbgs() << "\n";
   }
@@ -371,7 +368,7 @@ void GCOVBlock::dump() const {
     dbgs() << "\tDestination Edges : ";
     for (EdgeIterator I = DstEdges.begin(), E = DstEdges.end(); I != E; ++I) {
       const GCOVEdge *Edge = *I;
-      dbgs() << Edge->Dst->Number << " (" << Edge->Count << "), ";
+      dbgs() << Edge->Dst.Number << " (" << Edge->Count << "), ";
     }
     dbgs() << "\n";
   }
@@ -435,11 +432,35 @@ static raw_ostream &operator<<(raw_ostream &OS, const formatBranchInfo &FBI) {
   return OS;
 }
 
+namespace {
+class LineConsumer {
+  std::unique_ptr<MemoryBuffer> Buffer;
+  StringRef Remaining;
+public:
+  LineConsumer(StringRef Filename) {
+    if (error_code EC = MemoryBuffer::getFileOrSTDIN(Filename, Buffer)) {
+      errs() << Filename << ": " << EC.message() << "\n";
+      Remaining = "";
+    } else
+      Remaining = Buffer->getBuffer();
+  }
+  bool empty() { return Remaining.empty(); }
+  void printNext(raw_ostream &OS, uint32_t LineNum) {
+    StringRef Line;
+    if (empty())
+      Line = "/*EOF*/";
+    else
+      std::tie(Line, Remaining) = Remaining.split("\n");
+    OS << format("%5u:", LineNum) << Line << "\n";
+  }
+};
+}
+
 /// Convert a path to a gcov filename. If PreservePaths is true, this
 /// translates "/" to "#", ".." to "^", and drops ".", to match gcov.
 static std::string mangleCoveragePath(StringRef Filename, bool PreservePaths) {
   if (!PreservePaths)
-    return (sys::path::filename(Filename) + ".gcov").str();
+    return sys::path::filename(Filename).str();
 
   // This behaviour is defined by gcov in terms of text replacements, so it's
   // not likely to do anything useful on filesystems with different textual
@@ -467,28 +488,52 @@ static std::string mangleCoveragePath(StringRef Filename, bool PreservePaths) {
 
   if (S < I)
     Result.append(S, I);
-  Result.append(".gcov");
   return Result.str();
 }
 
+std::string FileInfo::getCoveragePath(StringRef Filename,
+                                      StringRef MainFilename) {
+  if (Options.NoOutput)
+    // This is probably a bug in gcov, but when -n is specified, paths aren't
+    // mangled at all, and the -l and -p options are ignored. Here, we do the
+    // same.
+    return Filename;
+
+  std::string CoveragePath;
+  if (Options.LongFileNames && !Filename.equals(MainFilename))
+    CoveragePath =
+        mangleCoveragePath(MainFilename, Options.PreservePaths) + "##";
+  CoveragePath +=
+      mangleCoveragePath(Filename, Options.PreservePaths) + ".gcov";
+  return CoveragePath;
+}
+
+std::unique_ptr<raw_ostream>
+FileInfo::openCoveragePath(StringRef CoveragePath) {
+  if (Options.NoOutput)
+    return llvm::make_unique<raw_null_ostream>();
+
+  std::string ErrorInfo;
+  auto OS = llvm::make_unique<raw_fd_ostream>(CoveragePath.str().c_str(),
+                                              ErrorInfo, sys::fs::F_Text);
+  if (!ErrorInfo.empty()) {
+    errs() << ErrorInfo << "\n";
+    return llvm::make_unique<raw_null_ostream>();
+  }
+  return std::move(OS);
+}
+
 /// print -  Print source files with collected line count information.
-void FileInfo::print(StringRef GCNOFile, StringRef GCDAFile) {
+void FileInfo::print(StringRef MainFilename, StringRef GCNOFile,
+                     StringRef GCDAFile) {
   for (StringMap<LineData>::const_iterator I = LineInfo.begin(),
          E = LineInfo.end(); I != E; ++I) {
     StringRef Filename = I->first();
-    std::unique_ptr<MemoryBuffer> Buff;
-    if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
-      errs() << Filename << ": " << ec.message() << "\n";
-      return;
-    }
-    StringRef AllLines = Buff->getBuffer();
+    auto AllLines = LineConsumer(Filename);
 
-    std::string CoveragePath = mangleCoveragePath(Filename,
-                                                  Options.PreservePaths);
-    std::string ErrorInfo;
-    raw_fd_ostream OS(CoveragePath.c_str(), ErrorInfo, sys::fs::F_Text);
-    if (!ErrorInfo.empty())
-      errs() << ErrorInfo << "\n";
+    std::string CoveragePath = getCoveragePath(Filename, MainFilename);
+    std::unique_ptr<raw_ostream> S = openCoveragePath(CoveragePath);
+    raw_ostream &OS = *S;
 
     OS << "        -:    0:Source:" << Filename << "\n";
     OS << "        -:    0:Graph:" << GCNOFile << "\n";
@@ -498,7 +543,8 @@ void FileInfo::print(StringRef GCNOFile, StringRef GCDAFile) {
 
     const LineData &Line = I->second;
     GCOVCoverage FileCoverage(Filename);
-    for (uint32_t LineIndex = 0; !AllLines.empty(); ++LineIndex) {
+    for (uint32_t LineIndex = 0;
+         LineIndex < Line.LastLine || !AllLines.empty(); ++LineIndex) {
       if (Options.BranchInfo) {
         FunctionLines::const_iterator FuncsIt = Line.Functions.find(LineIndex);
         if (FuncsIt != Line.Functions.end())
@@ -509,9 +555,7 @@ void FileInfo::print(StringRef GCNOFile, StringRef GCDAFile) {
       if (BlocksIt == Line.Blocks.end()) {
         // No basic blocks are on this line. Not an executable line of code.
         OS << "        -:";
-        std::pair<StringRef, StringRef> P = AllLines.split('\n');
-        OS << format("%5u:", LineIndex+1) << P.first << "\n";
-        AllLines = P.second;
+        AllLines.printNext(OS, LineIndex + 1);
       } else {
         const BlockVector &Blocks = BlocksIt->second;
 
@@ -573,9 +617,7 @@ void FileInfo::print(StringRef GCNOFile, StringRef GCDAFile) {
         }
         ++FileCoverage.LogicalLines;
 
-        std::pair<StringRef, StringRef> P = AllLines.split('\n');
-        OS << format("%5u:", LineIndex+1) << P.first << "\n";
-        AllLines = P.second;
+        AllLines.printNext(OS, LineIndex + 1);
 
         uint32_t BlockNo = 0;
         uint32_t EdgeNo = 0;
@@ -605,10 +647,11 @@ void FileInfo::print(StringRef GCNOFile, StringRef GCDAFile) {
   if (Options.FuncCoverage)
     printFuncCoverage();
   printFileCoverage();
+  return;
 }
 
 /// printFunctionSummary - Print function and block summary.
-void FileInfo::printFunctionSummary(raw_fd_ostream &OS,
+void FileInfo::printFunctionSummary(raw_ostream &OS,
                                     const FunctionVector &Funcs) const {
   for (FunctionVector::const_iterator I = Funcs.begin(), E = Funcs.end();
          I != E; ++I) {
@@ -617,8 +660,8 @@ void FileInfo::printFunctionSummary(raw_fd_ostream &OS,
     uint32_t BlocksExec = 0;
     for (GCOVFunction::BlockIterator I = Func->block_begin(),
            E = Func->block_end(); I != E; ++I) {
-      const GCOVBlock *Block = *I;
-      if (Block->getNumDstEdges() && Block->getCount())
+      const GCOVBlock &Block = **I;
+      if (Block.getNumDstEdges() && Block.getCount())
           ++BlocksExec;
     }
 
@@ -630,7 +673,7 @@ void FileInfo::printFunctionSummary(raw_fd_ostream &OS,
 }
 
 /// printBlockInfo - Output counts for each block.
-void FileInfo::printBlockInfo(raw_fd_ostream &OS, const GCOVBlock &Block,
+void FileInfo::printBlockInfo(raw_ostream &OS, const GCOVBlock &Block,
                               uint32_t LineIndex, uint32_t &BlockNo) const {
   if (Block.getCount() == 0)
     OS << "    $$$$$:";
@@ -640,7 +683,7 @@ void FileInfo::printBlockInfo(raw_fd_ostream &OS, const GCOVBlock &Block,
 }
 
 /// printBranchInfo - Print conditional branch probabilities.
-void FileInfo::printBranchInfo(raw_fd_ostream &OS, const GCOVBlock &Block,
+void FileInfo::printBranchInfo(raw_ostream &OS, const GCOVBlock &Block,
                                GCOVCoverage &Coverage, uint32_t &EdgeNo) {
   SmallVector<uint64_t, 16> BranchCounts;
   uint64_t TotalCounts = 0;
@@ -670,7 +713,7 @@ void FileInfo::printBranchInfo(raw_fd_ostream &OS, const GCOVBlock &Block,
 }
 
 /// printUncondBranchInfo - Print unconditional branch probabilities.
-void FileInfo::printUncondBranchInfo(raw_fd_ostream &OS, uint32_t &EdgeNo,
+void FileInfo::printUncondBranchInfo(raw_ostream &OS, uint32_t &EdgeNo,
                                      uint64_t Count) const {
   OS << format("unconditional %2u ", EdgeNo++)
      << formatBranchInfo(Options, Count, Count) << "\n";
@@ -716,6 +759,8 @@ void FileInfo::printFileCoverage() const {
     const GCOVCoverage &Coverage = I->second;
     outs() << "File '" << Coverage.Name << "'\n";
     printCoverage(Coverage);
-    outs() << Coverage.Name << ":creating '" << Filename << "'\n\n";
+    if (!Options.NoOutput)
+      outs() << Coverage.Name << ":creating '" << Filename << "'\n";
+    outs() << "\n";
   }
 }
diff --git a/lib/IR/Globals.cpp b/lib/IR/Globals.cpp
index f338dd7..c905cfe 100644
--- a/lib/IR/Globals.cpp
+++ b/lib/IR/Globals.cpp
@@ -53,23 +53,41 @@ void GlobalValue::destroyConstant() {
 /// copyAttributesFrom - copy all additional attributes (those not needed to
 /// create a GlobalValue) from the GlobalValue Src to this one.
 void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
-  setAlignment(Src->getAlignment());
-  setSection(Src->getSection());
   setVisibility(Src->getVisibility());
   setUnnamedAddr(Src->hasUnnamedAddr());
   setDLLStorageClass(Src->getDLLStorageClass());
 }
 
-void GlobalValue::setAlignment(unsigned Align) {
-  assert((!isa<GlobalAlias>(this) || !Align) &&
-         "GlobalAlias should not have an alignment!");
+unsigned GlobalValue::getAlignment() const {
+  if (auto *GA = dyn_cast<GlobalAlias>(this))
+    return GA->getAliasee()->getAlignment();
+
+  return cast<GlobalObject>(this)->getAlignment();
+}
+
+void GlobalObject::setAlignment(unsigned Align) {
   assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
   assert(Align <= MaximumAlignment &&
          "Alignment is greater than MaximumAlignment!");
-  Alignment = Log2_32(Align) + 1;
+  setGlobalValueSubClassData(Log2_32(Align) + 1);
   assert(getAlignment() == Align && "Alignment representation error!");
 }
 
+void GlobalObject::copyAttributesFrom(const GlobalValue *Src) {
+  const auto *GV = cast<GlobalObject>(Src);
+  GlobalValue::copyAttributesFrom(GV);
+  setAlignment(GV->getAlignment());
+  setSection(GV->getSection());
+}
+
+const std::string &GlobalValue::getSection() const {
+  if (auto *GA = dyn_cast<GlobalAlias>(this))
+    return GA->getAliasee()->getSection();
+  return cast<GlobalObject>(this)->getSection();
+}
+
+void GlobalObject::setSection(StringRef S) { Section = S; }
+
 bool GlobalValue::isDeclaration() const {
   // Globals are definitions if they have an initializer.
   if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
@@ -83,22 +101,20 @@ bool GlobalValue::isDeclaration() const {
   assert(isa<GlobalAlias>(this));
   return false;
 }
-  
+
 //===----------------------------------------------------------------------===//
 // GlobalVariable Implementation
 //===----------------------------------------------------------------------===//
 
 GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
-                               Constant *InitVal,
-                               const Twine &Name, ThreadLocalMode TLMode,
-                               unsigned AddressSpace,
+                               Constant *InitVal, const Twine &Name,
+                               ThreadLocalMode TLMode, unsigned AddressSpace,
                                bool isExternallyInitialized)
-  : GlobalValue(PointerType::get(Ty, AddressSpace),
-                Value::GlobalVariableVal,
-                OperandTraits<GlobalVariable>::op_begin(this),
-                InitVal != 0, Link, Name),
-    isConstantGlobal(constant), threadLocalMode(TLMode),
-    isExternallyInitializedConstant(isExternallyInitialized) {
+    : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
+                   OperandTraits<GlobalVariable>::op_begin(this),
+                   InitVal != nullptr, Link, Name),
+      isConstantGlobal(constant), threadLocalMode(TLMode),
+      isExternallyInitializedConstant(isExternallyInitialized) {
   if (InitVal) {
     assert(InitVal->getType() == Ty &&
            "Initializer should be the same type as the GlobalVariable!");
@@ -110,24 +126,22 @@ GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
 
 GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
                                LinkageTypes Link, Constant *InitVal,
-                               const Twine &Name,
-                               GlobalVariable *Before, ThreadLocalMode TLMode,
-                               unsigned AddressSpace,
+                               const Twine &Name, GlobalVariable *Before,
+                               ThreadLocalMode TLMode, unsigned AddressSpace,
                                bool isExternallyInitialized)
-  : GlobalValue(PointerType::get(Ty, AddressSpace),
-                Value::GlobalVariableVal,
-                OperandTraits<GlobalVariable>::op_begin(this),
-                InitVal != 0, Link, Name),
-    isConstantGlobal(constant), threadLocalMode(TLMode),
-    isExternallyInitializedConstant(isExternallyInitialized) {
+    : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
+                   OperandTraits<GlobalVariable>::op_begin(this),
+                   InitVal != nullptr, Link, Name),
+      isConstantGlobal(constant), threadLocalMode(TLMode),
+      isExternallyInitializedConstant(isExternallyInitialized) {
   if (InitVal) {
     assert(InitVal->getType() == Ty &&
            "Initializer should be the same type as the GlobalVariable!");
     Op<0>() = InitVal;
   }
-  
+
   LeakDetector::addGarbageObject(this);
-  
+
   if (Before)
     Before->getParent()->getGlobalList().insert(Before, this);
   else
@@ -171,9 +185,9 @@ void GlobalVariable::replaceUsesOfWithOnConstant(Value *From, Value *To,
 }
 
 void GlobalVariable::setInitializer(Constant *InitVal) {
-  if (InitVal == 0) {
+  if (!InitVal) {
     if (hasInitializer()) {
-      Op<0>().set(0);
+      Op<0>().set(nullptr);
       NumOperands = 0;
     }
   } else {
@@ -189,7 +203,7 @@ void GlobalVariable::setInitializer(Constant *InitVal) {
 /// create a GlobalVariable) from the GlobalVariable Src to this one.
 void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
   assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!");
-  GlobalValue::copyAttributesFrom(Src);
+  GlobalObject::copyAttributesFrom(Src);
   const GlobalVariable *SrcVar = cast<GlobalVariable>(Src);
   setThreadLocalMode(SrcVar->getThreadLocalMode());
 }
@@ -199,20 +213,47 @@ void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
 // GlobalAlias Implementation
 //===----------------------------------------------------------------------===//
 
-GlobalAlias::GlobalAlias(Type *Ty, LinkageTypes Link,
-                         const Twine &Name, Constant* aliasee,
+GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
+                         const Twine &Name, GlobalObject *Aliasee,
                          Module *ParentModule)
-  : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) {
+    : GlobalValue(PointerType::get(Ty, AddressSpace), Value::GlobalAliasVal,
+                  &Op<0>(), 1, Link, Name) {
   LeakDetector::addGarbageObject(this);
-
-  if (aliasee)
-    assert(aliasee->getType() == Ty && "Alias and aliasee types should match!");
-  Op<0>() = aliasee;
+  Op<0>() = Aliasee;
 
   if (ParentModule)
     ParentModule->getAliasList().push_back(this);
 }
 
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+                                 LinkageTypes Link, const Twine &Name,
+                                 GlobalObject *Aliasee, Module *ParentModule) {
+  return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule);
+}
+
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+                                 LinkageTypes Linkage, const Twine &Name,
+                                 Module *Parent) {
+  return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent);
+}
+
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+                                 LinkageTypes Linkage, const Twine &Name,
+                                 GlobalObject *Aliasee) {
+  return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent());
+}
+
+GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name,
+                                 GlobalObject *Aliasee) {
+  PointerType *PTy = Aliasee->getType();
+  return create(PTy->getElementType(), PTy->getAddressSpace(), Link, Name,
+                Aliasee);
+}
+
+GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalObject *Aliasee) {
+  return create(Aliasee->getLinkage(), Name, Aliasee);
+}
+
 void GlobalAlias::setParent(Module *parent) {
   if (getParent())
     LeakDetector::addGarbageObject(this);
@@ -229,42 +270,4 @@ void GlobalAlias::eraseFromParent() {
   getParent()->getAliasList().erase(this);
 }
 
-void GlobalAlias::setAliasee(Constant *Aliasee) {
-  assert((!Aliasee || Aliasee->getType() == getType()) &&
-         "Alias and aliasee types should match!");
-  
-  setOperand(0, Aliasee);
-}
-
-static GlobalValue *getAliaseeGV(GlobalAlias *GA) {
-  Constant *C = GA->getAliasee();
-  assert(C && "Must alias something");
-
-  if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
-    return GV;
-
-  ConstantExpr *CE = cast<ConstantExpr>(C);
-  assert((CE->getOpcode() == Instruction::BitCast ||
-          CE->getOpcode() == Instruction::AddrSpaceCast ||
-          CE->getOpcode() == Instruction::GetElementPtr) &&
-         "Unsupported aliasee");
-
-  return cast<GlobalValue>(CE->getOperand(0));
-}
-
-GlobalValue *GlobalAlias::getAliasedGlobal() {
-  SmallPtrSet<GlobalValue*, 3> Visited;
-
-  GlobalAlias *GA = this;
-
-  for (;;) {
-    GlobalValue *GV = getAliaseeGV(GA);
-    if (!Visited.insert(GV))
-      return 0;
-
-    // Iterate over aliasing chain.
-    GA = dyn_cast<GlobalAlias>(GV);
-    if (!GA)
-      return GV;
-  }
-}
+void GlobalAlias::setAliasee(GlobalObject *Aliasee) { setOperand(0, Aliasee); }
diff --git a/lib/IR/IRPrintingPasses.cpp b/lib/IR/IRPrintingPasses.cpp
index 099c27c..c8a1747 100644
--- a/lib/IR/IRPrintingPasses.cpp
+++ b/lib/IR/IRPrintingPasses.cpp
@@ -94,7 +94,7 @@ public:
     return false;
   }
 
-  void getAnalysisUsage(AnalysisUsage &AU) const override{
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesAll();
   }
 };
diff --git a/lib/IR/InlineAsm.cpp b/lib/IR/InlineAsm.cpp
index 62d191d..a3e1da3b1 100644
--- a/lib/IR/InlineAsm.cpp
+++ b/lib/IR/InlineAsm.cpp
@@ -274,7 +274,7 @@ bool InlineAsm::Verify(FunctionType *Ty, StringRef ConstStr) {
     break;
   default:
     StructType *STy = dyn_cast<StructType>(Ty->getReturnType());
-    if (STy == 0 || STy->getNumElements() != NumOutputs)
+    if (!STy || STy->getNumElements() != NumOutputs)
       return false;
     break;
   }      
diff --git a/lib/IR/Instruction.cpp b/lib/IR/Instruction.cpp
index d31a92e..28cc4cb 100644
--- a/lib/IR/Instruction.cpp
+++ b/lib/IR/Instruction.cpp
@@ -23,7 +23,7 @@ using namespace llvm;
 
 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
                          Instruction *InsertBefore)
-  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
+  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(nullptr) {
   // Make sure that we get added to a basicblock
   LeakDetector::addGarbageObject(this);
 
@@ -41,7 +41,7 @@ const DataLayout *Instruction::getDataLayout() const {
 
 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
                          BasicBlock *InsertAtEnd)
-  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
+  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(nullptr) {
   // Make sure that we get added to a basicblock
   LeakDetector::addGarbageObject(this);
 
@@ -53,7 +53,7 @@ Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
 
 // Out of line virtual method, so the vtable, etc has a home.
 Instruction::~Instruction() {
-  assert(Parent == 0 && "Instruction still linked in the program!");
+  assert(!Parent && "Instruction still linked in the program!");
   if (hasMetadataHashEntry())
     clearMetadataHashEntries();
 }
@@ -262,6 +262,58 @@ const char *Instruction::getOpcodeName(unsigned OpCode) {
   }
 }
 
+/// Return true if both instructions have the same special state
+/// This must be kept in sync with lib/Transforms/IPO/MergeFunctions.cpp.
+static bool haveSameSpecialState(const Instruction *I1, const Instruction *I2,
+                                 bool IgnoreAlignment = false) {
+  assert(I1->getOpcode() == I2->getOpcode() &&
+         "Can not compare special state of different instructions");
+
+  if (const LoadInst *LI = dyn_cast<LoadInst>(I1))
+    return LI->isVolatile() == cast<LoadInst>(I2)->isVolatile() &&
+           (LI->getAlignment() == cast<LoadInst>(I2)->getAlignment() ||
+            IgnoreAlignment) &&
+           LI->getOrdering() == cast<LoadInst>(I2)->getOrdering() &&
+           LI->getSynchScope() == cast<LoadInst>(I2)->getSynchScope();
+  if (const StoreInst *SI = dyn_cast<StoreInst>(I1))
+    return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() &&
+           (SI->getAlignment() == cast<StoreInst>(I2)->getAlignment() ||
+            IgnoreAlignment) &&
+           SI->getOrdering() == cast<StoreInst>(I2)->getOrdering() &&
+           SI->getSynchScope() == cast<StoreInst>(I2)->getSynchScope();
+  if (const CmpInst *CI = dyn_cast<CmpInst>(I1))
+    return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate();
+  if (const CallInst *CI = dyn_cast<CallInst>(I1))
+    return CI->isTailCall() == cast<CallInst>(I2)->isTailCall() &&
+           CI->getCallingConv() == cast<CallInst>(I2)->getCallingConv() &&
+           CI->getAttributes() == cast<CallInst>(I2)->getAttributes();
+  if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1))
+    return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() &&
+           CI->getAttributes() ==
+             cast<InvokeInst>(I2)->getAttributes();
+  if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1))
+    return IVI->getIndices() == cast<InsertValueInst>(I2)->getIndices();
+  if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1))
+    return EVI->getIndices() == cast<ExtractValueInst>(I2)->getIndices();
+  if (const FenceInst *FI = dyn_cast<FenceInst>(I1))
+    return FI->getOrdering() == cast<FenceInst>(I2)->getOrdering() &&
+           FI->getSynchScope() == cast<FenceInst>(I2)->getSynchScope();
+  if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I1))
+    return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I2)->isVolatile() &&
+           CXI->getSuccessOrdering() ==
+               cast<AtomicCmpXchgInst>(I2)->getSuccessOrdering() &&
+           CXI->getFailureOrdering() ==
+               cast<AtomicCmpXchgInst>(I2)->getFailureOrdering() &&
+           CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I2)->getSynchScope();
+  if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I1))
+    return RMWI->getOperation() == cast<AtomicRMWInst>(I2)->getOperation() &&
+           RMWI->isVolatile() == cast<AtomicRMWInst>(I2)->isVolatile() &&
+           RMWI->getOrdering() == cast<AtomicRMWInst>(I2)->getOrdering() &&
+           RMWI->getSynchScope() == cast<AtomicRMWInst>(I2)->getSynchScope();
+
+  return true;
+}
+
 /// isIdenticalTo - Return true if the specified instruction is exactly
 /// identical to the current one.  This means that all operands match and any
 /// extra information (e.g. load is volatile) agree.
@@ -284,51 +336,13 @@ bool Instruction::isIdenticalToWhenDefined(const Instruction *I) const {
   if (!std::equal(op_begin(), op_end(), I->op_begin()))
     return false;
 
-  // Check special state that is a part of some instructions.
-  if (const LoadInst *LI = dyn_cast<LoadInst>(this))
-    return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
-           LI->getAlignment() == cast<LoadInst>(I)->getAlignment() &&
-           LI->getOrdering() == cast<LoadInst>(I)->getOrdering() &&
-           LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope();
-  if (const StoreInst *SI = dyn_cast<StoreInst>(this))
-    return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
-           SI->getAlignment() == cast<StoreInst>(I)->getAlignment() &&
-           SI->getOrdering() == cast<StoreInst>(I)->getOrdering() &&
-           SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope();
-  if (const CmpInst *CI = dyn_cast<CmpInst>(this))
-    return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
-  if (const CallInst *CI = dyn_cast<CallInst>(this))
-    return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
-           CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
-           CI->getAttributes() == cast<CallInst>(I)->getAttributes();
-  if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
-    return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
-           CI->getAttributes() == cast<InvokeInst>(I)->getAttributes();
-  if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this))
-    return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices();
-  if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this))
-    return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices();
-  if (const FenceInst *FI = dyn_cast<FenceInst>(this))
-    return FI->getOrdering() == cast<FenceInst>(FI)->getOrdering() &&
-           FI->getSynchScope() == cast<FenceInst>(FI)->getSynchScope();
-  if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(this))
-    return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I)->isVolatile() &&
-           CXI->getSuccessOrdering() ==
-               cast<AtomicCmpXchgInst>(I)->getSuccessOrdering() &&
-           CXI->getFailureOrdering() ==
-               cast<AtomicCmpXchgInst>(I)->getFailureOrdering() &&
-           CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I)->getSynchScope();
-  if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(this))
-    return RMWI->getOperation() == cast<AtomicRMWInst>(I)->getOperation() &&
-           RMWI->isVolatile() == cast<AtomicRMWInst>(I)->isVolatile() &&
-           RMWI->getOrdering() == cast<AtomicRMWInst>(I)->getOrdering() &&
-           RMWI->getSynchScope() == cast<AtomicRMWInst>(I)->getSynchScope();
   if (const PHINode *thisPHI = dyn_cast<PHINode>(this)) {
     const PHINode *otherPHI = cast<PHINode>(I);
     return std::equal(thisPHI->block_begin(), thisPHI->block_end(),
                       otherPHI->block_begin());
   }
-  return true;
+
+  return haveSameSpecialState(this, I);
 }
 
 // isSameOperationAs
@@ -355,50 +369,7 @@ bool Instruction::isSameOperationAs(const Instruction *I,
         getOperand(i)->getType() != I->getOperand(i)->getType())
       return false;
 
-  // Check special state that is a part of some instructions.
-  if (const LoadInst *LI = dyn_cast<LoadInst>(this))
-    return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
-           (LI->getAlignment() == cast<LoadInst>(I)->getAlignment() ||
-            IgnoreAlignment) &&
-           LI->getOrdering() == cast<LoadInst>(I)->getOrdering() &&
-           LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope();
-  if (const StoreInst *SI = dyn_cast<StoreInst>(this))
-    return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
-           (SI->getAlignment() == cast<StoreInst>(I)->getAlignment() ||
-            IgnoreAlignment) &&
-           SI->getOrdering() == cast<StoreInst>(I)->getOrdering() &&
-           SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope();
-  if (const CmpInst *CI = dyn_cast<CmpInst>(this))
-    return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
-  if (const CallInst *CI = dyn_cast<CallInst>(this))
-    return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
-           CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
-           CI->getAttributes() == cast<CallInst>(I)->getAttributes();
-  if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
-    return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
-           CI->getAttributes() ==
-             cast<InvokeInst>(I)->getAttributes();
-  if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this))
-    return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices();
-  if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this))
-    return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices();
-  if (const FenceInst *FI = dyn_cast<FenceInst>(this))
-    return FI->getOrdering() == cast<FenceInst>(I)->getOrdering() &&
-           FI->getSynchScope() == cast<FenceInst>(I)->getSynchScope();
-  if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(this))
-    return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I)->isVolatile() &&
-           CXI->getSuccessOrdering() ==
-               cast<AtomicCmpXchgInst>(I)->getSuccessOrdering() &&
-           CXI->getFailureOrdering() ==
-               cast<AtomicCmpXchgInst>(I)->getFailureOrdering() &&
-           CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I)->getSynchScope();
-  if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(this))
-    return RMWI->getOperation() == cast<AtomicRMWInst>(I)->getOperation() &&
-           RMWI->isVolatile() == cast<AtomicRMWInst>(I)->isVolatile() &&
-           RMWI->getOrdering() == cast<AtomicRMWInst>(I)->getOrdering() &&
-           RMWI->getSynchScope() == cast<AtomicRMWInst>(I)->getSynchScope();
-
-  return true;
+  return haveSameSpecialState(this, I, IgnoreAlignment);
 }
 
 /// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the
@@ -410,7 +381,7 @@ bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
     // instructions, just check to see whether the parent of the use matches up.
     const Instruction *I = cast<Instruction>(U.getUser());
     const PHINode *PN = dyn_cast<PHINode>(I);
-    if (PN == 0) {
+    if (!PN) {
       if (I->getParent() != BB)
         return true;
       continue;
diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 3aa8413..13c51b8 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -68,7 +68,7 @@ const char *SelectInst::areInvalidOperands(Value *Op0, Value *Op1, Value *Op2) {
     if (VT->getElementType() != Type::getInt1Ty(Op0->getContext()))
       return "vector select condition element type must be i1";
     VectorType *ET = dyn_cast<VectorType>(Op1->getType());
-    if (ET == 0)
+    if (!ET)
       return "selected values for vector select must be vectors";
     if (ET->getNumElements() != VT->getNumElements())
       return "vector select requires selected vectors to have "
@@ -76,7 +76,7 @@ const char *SelectInst::areInvalidOperands(Value *Op0, Value *Op1, Value *Op2) {
   } else if (Op0->getType() != Type::getInt1Ty(Op0->getContext())) {
     return "select condition must be i1 or <n x i1>";
   }
-  return 0;
+  return nullptr;
 }
 
 
@@ -123,7 +123,7 @@ Value *PHINode::removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty) {
   std::copy(block_begin() + Idx + 1, block_end(), block_begin() + Idx);
 
   // Nuke the last value.
-  Op<-1>().set(0);
+  Op<-1>().set(nullptr);
   --NumOperands;
 
   // If the PHI node is dead, because it has zero entries, nuke it now.
@@ -164,7 +164,7 @@ Value *PHINode::hasConstantValue() const {
   for (unsigned i = 1, e = getNumIncomingValues(); i != e; ++i)
     if (getIncomingValue(i) != ConstantValue && getIncomingValue(i) != this) {
       if (ConstantValue != this)
-        return 0; // Incoming values not all the same.
+        return nullptr; // Incoming values not all the same.
        // The case where the first value is this PHI.
       ConstantValue = getIncomingValue(i);
     }
@@ -180,14 +180,14 @@ Value *PHINode::hasConstantValue() const {
 LandingPadInst::LandingPadInst(Type *RetTy, Value *PersonalityFn,
                                unsigned NumReservedValues, const Twine &NameStr,
                                Instruction *InsertBefore)
-  : Instruction(RetTy, Instruction::LandingPad, 0, 0, InsertBefore) {
+  : Instruction(RetTy, Instruction::LandingPad, nullptr, 0, InsertBefore) {
   init(PersonalityFn, 1 + NumReservedValues, NameStr);
 }
 
 LandingPadInst::LandingPadInst(Type *RetTy, Value *PersonalityFn,
                                unsigned NumReservedValues, const Twine &NameStr,
                                BasicBlock *InsertAtEnd)
-  : Instruction(RetTy, Instruction::LandingPad, 0, 0, InsertAtEnd) {
+  : Instruction(RetTy, Instruction::LandingPad, nullptr, 0, InsertAtEnd) {
   init(PersonalityFn, 1 + NumReservedValues, NameStr);
 }
 
@@ -324,7 +324,7 @@ CallInst::CallInst(const CallInst &CI)
                 OperandTraits<CallInst>::op_end(this) - CI.getNumOperands(),
                 CI.getNumOperands()) {
   setAttributes(CI.getAttributes());
-  setTailCall(CI.isTailCall());
+  setTailCallKind(CI.getTailCallKind());
   setCallingConv(CI.getCallingConv());
     
   std::copy(CI.op_begin(), CI.op_end(), op_begin());
@@ -420,8 +420,8 @@ static Instruction *createMalloc(Instruction *InsertBefore,
     // prototype malloc as "void *malloc(size_t)"
     MallocFunc = M->getOrInsertFunction("malloc", BPTy, IntPtrTy, NULL);
   PointerType *AllocPtrType = PointerType::getUnqual(AllocTy);
-  CallInst *MCall = NULL;
-  Instruction *Result = NULL;
+  CallInst *MCall = nullptr;
+  Instruction *Result = nullptr;
   if (InsertBefore) {
     MCall = CallInst::Create(MallocFunc, AllocSize, "malloccall", InsertBefore);
     Result = MCall;
@@ -458,7 +458,7 @@ Instruction *CallInst::CreateMalloc(Instruction *InsertBefore,
                                     Value *AllocSize, Value *ArraySize,
                                     Function * MallocF,
                                     const Twine &Name) {
-  return createMalloc(InsertBefore, NULL, IntPtrTy, AllocTy, AllocSize,
+  return createMalloc(InsertBefore, nullptr, IntPtrTy, AllocTy, AllocSize,
                       ArraySize, MallocF, Name);
 }
 
@@ -474,7 +474,7 @@ Instruction *CallInst::CreateMalloc(BasicBlock *InsertAtEnd,
                                     Type *IntPtrTy, Type *AllocTy,
                                     Value *AllocSize, Value *ArraySize, 
                                     Function *MallocF, const Twine &Name) {
-  return createMalloc(NULL, InsertAtEnd, IntPtrTy, AllocTy, AllocSize,
+  return createMalloc(nullptr, InsertAtEnd, IntPtrTy, AllocTy, AllocSize,
                       ArraySize, MallocF, Name);
 }
 
@@ -492,7 +492,7 @@ static Instruction* createFree(Value* Source, Instruction *InsertBefore,
   Type *IntPtrTy = Type::getInt8PtrTy(M->getContext());
   // prototype free as "void free(void*)"
   Value *FreeFunc = M->getOrInsertFunction("free", VoidTy, IntPtrTy, NULL);
-  CallInst* Result = NULL;
+  CallInst* Result = nullptr;
   Value *PtrCast = Source;
   if (InsertBefore) {
     if (Source->getType() != IntPtrTy)
@@ -512,14 +512,14 @@ static Instruction* createFree(Value* Source, Instruction *InsertBefore,
 
 /// CreateFree - Generate the IR for a call to the builtin free function.
 Instruction * CallInst::CreateFree(Value* Source, Instruction *InsertBefore) {
-  return createFree(Source, InsertBefore, NULL);
+  return createFree(Source, InsertBefore, nullptr);
 }
 
 /// CreateFree - Generate the IR for a call to the builtin free function.
 /// Note: This function does not add the call to the basic block, that is the
 /// responsibility of the caller.
 Instruction* CallInst::CreateFree(Value* Source, BasicBlock *InsertAtEnd) {
-  Instruction* FreeCall = createFree(Source, NULL, InsertAtEnd);
+  Instruction* FreeCall = createFree(Source, nullptr, InsertAtEnd);
   assert(FreeCall && "CreateFree did not create a CallInst");
   return FreeCall;
 }
@@ -699,11 +699,11 @@ BasicBlock *ResumeInst::getSuccessorV(unsigned idx) const {
 UnreachableInst::UnreachableInst(LLVMContext &Context, 
                                  Instruction *InsertBefore)
   : TerminatorInst(Type::getVoidTy(Context), Instruction::Unreachable,
-                   0, 0, InsertBefore) {
+                   nullptr, 0, InsertBefore) {
 }
 UnreachableInst::UnreachableInst(LLVMContext &Context, BasicBlock *InsertAtEnd)
   : TerminatorInst(Type::getVoidTy(Context), Instruction::Unreachable,
-                   0, 0, InsertAtEnd) {
+                   nullptr, 0, InsertAtEnd) {
 }
 
 unsigned UnreachableInst::getNumSuccessorsV() const {
@@ -732,7 +732,7 @@ BranchInst::BranchInst(BasicBlock *IfTrue, Instruction *InsertBefore)
   : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                    OperandTraits<BranchInst>::op_end(this) - 1,
                    1, InsertBefore) {
-  assert(IfTrue != 0 && "Branch destination may not be null!");
+  assert(IfTrue && "Branch destination may not be null!");
   Op<-1>() = IfTrue;
 }
 BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *IfFalse, Value *Cond,
@@ -752,7 +752,7 @@ BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *InsertAtEnd)
   : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                    OperandTraits<BranchInst>::op_end(this) - 1,
                    1, InsertAtEnd) {
-  assert(IfTrue != 0 && "Branch destination may not be null!");
+  assert(IfTrue && "Branch destination may not be null!");
   Op<-1>() = IfTrue;
 }
 
@@ -852,7 +852,7 @@ AllocaInst::AllocaInst(Type *Ty, Value *ArraySize,
 AllocaInst::AllocaInst(Type *Ty, const Twine &Name,
                        Instruction *InsertBefore)
   : UnaryInstruction(PointerType::getUnqual(Ty), Alloca,
-                     getAISize(Ty->getContext(), 0), InsertBefore) {
+                     getAISize(Ty->getContext(), nullptr), InsertBefore) {
   setAlignment(0);
   assert(!Ty->isVoidTy() && "Cannot allocate void!");
   setName(Name);
@@ -861,7 +861,7 @@ AllocaInst::AllocaInst(Type *Ty, const Twine &Name,
 AllocaInst::AllocaInst(Type *Ty, const Twine &Name,
                        BasicBlock *InsertAtEnd)
   : UnaryInstruction(PointerType::getUnqual(Ty), Alloca,
-                     getAISize(Ty->getContext(), 0), InsertAtEnd) {
+                     getAISize(Ty->getContext(), nullptr), InsertAtEnd) {
   setAlignment(0);
   assert(!Ty->isVoidTy() && "Cannot allocate void!");
   setName(Name);
@@ -1323,7 +1323,7 @@ AtomicRMWInst::AtomicRMWInst(BinOp Operation, Value *Ptr, Value *Val,
 FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering, 
                      SynchronizationScope SynchScope,
                      Instruction *InsertBefore)
-  : Instruction(Type::getVoidTy(C), Fence, 0, 0, InsertBefore) {
+  : Instruction(Type::getVoidTy(C), Fence, nullptr, 0, InsertBefore) {
   setOrdering(Ordering);
   setSynchScope(SynchScope);
 }
@@ -1331,7 +1331,7 @@ FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering,
 FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering, 
                      SynchronizationScope SynchScope,
                      BasicBlock *InsertAtEnd)
-  : Instruction(Type::getVoidTy(C), Fence, 0, 0, InsertAtEnd) {
+  : Instruction(Type::getVoidTy(C), Fence, nullptr, 0, InsertAtEnd) {
   setOrdering(Ordering);
   setSynchScope(SynchScope);
 }
@@ -1369,7 +1369,7 @@ GetElementPtrInst::GetElementPtrInst(const GetElementPtrInst &GEPI)
 template <typename IndexTy>
 static Type *getIndexedTypeInternal(Type *Ptr, ArrayRef<IndexTy> IdxList) {
   PointerType *PTy = dyn_cast<PointerType>(Ptr->getScalarType());
-  if (!PTy) return 0;   // Type isn't a pointer type!
+  if (!PTy) return nullptr;   // Type isn't a pointer type!
   Type *Agg = PTy->getElementType();
 
   // Handle the special case of the empty set index set, which is always valid.
@@ -1379,17 +1379,17 @@ static Type *getIndexedTypeInternal(Type *Ptr, ArrayRef<IndexTy> IdxList) {
   // If there is at least one index, the top level type must be sized, otherwise
   // it cannot be 'stepped over'.
   if (!Agg->isSized())
-    return 0;
+    return nullptr;
 
   unsigned CurIdx = 1;
   for (; CurIdx != IdxList.size(); ++CurIdx) {
     CompositeType *CT = dyn_cast<CompositeType>(Agg);
-    if (!CT || CT->isPointerTy()) return 0;
+    if (!CT || CT->isPointerTy()) return nullptr;
     IndexTy Index = IdxList[CurIdx];
-    if (!CT->indexValid(Index)) return 0;
+    if (!CT->indexValid(Index)) return nullptr;
     Agg = CT->getTypeAtIndex(Index);
   }
-  return CurIdx == IdxList.size() ? Agg : 0;
+  return CurIdx == IdxList.size() ? Agg : nullptr;
 }
 
 Type *GetElementPtrInst::getIndexedType(Type *Ptr, ArrayRef<Value *> IdxList) {
@@ -1479,7 +1479,7 @@ ExtractElementInst::ExtractElementInst(Value *Val, Value *Index,
 
 
 bool ExtractElementInst::isValidOperands(const Value *Val, const Value *Index) {
-  if (!Val->getType()->isVectorTy() || !Index->getType()->isIntegerTy(32))
+  if (!Val->getType()->isVectorTy() || !Index->getType()->isIntegerTy())
     return false;
   return true;
 }
@@ -1526,7 +1526,7 @@ bool InsertElementInst::isValidOperands(const Value *Vec, const Value *Elt,
   if (Elt->getType() != cast<VectorType>(Vec->getType())->getElementType())
     return false;// Second operand of insertelement must be vector element type.
     
-  if (!Index->getType()->isIntegerTy(32))
+  if (!Index->getType()->isIntegerTy())
     return false;  // Third operand of insertelement must be i32.
   return true;
 }
@@ -1579,7 +1579,7 @@ bool ShuffleVectorInst::isValidOperands(const Value *V1, const Value *V2,
   
   // Mask must be vector of i32.
   VectorType *MaskTy = dyn_cast<VectorType>(Mask->getType());
-  if (MaskTy == 0 || !MaskTy->getElementType()->isIntegerTy(32))
+  if (!MaskTy || !MaskTy->getElementType()->isIntegerTy(32))
     return false;
 
   // Check to see if Mask is valid.
@@ -1721,13 +1721,13 @@ Type *ExtractValueInst::getIndexedType(Type *Agg,
     // as easy to check those manually as well.
     if (ArrayType *AT = dyn_cast<ArrayType>(Agg)) {
       if (Index >= AT->getNumElements())
-        return 0;
+        return nullptr;
     } else if (StructType *ST = dyn_cast<StructType>(Agg)) {
       if (Index >= ST->getNumElements())
-        return 0;
+        return nullptr;
     } else {
       // Not a valid type to index into.
-      return 0;
+      return nullptr;
     }
 
     Agg = cast<CompositeType>(Agg)->getTypeAtIndex(Index);
@@ -2130,7 +2130,7 @@ bool CastInst::isNoopCast(const DataLayout *DL) const {
     return isNoopCast(Type::getInt64Ty(getContext()));
   }
 
-  Type *PtrOpTy = 0;
+  Type *PtrOpTy = nullptr;
   if (getOpcode() == Instruction::PtrToInt)
     PtrOpTy = getOperand(0)->getType();
   else if (getOpcode() == Instruction::IntToPtr)
@@ -3361,7 +3361,7 @@ void SwitchInst::init(Value *Value, BasicBlock *Default, unsigned NumReserved) {
 SwitchInst::SwitchInst(Value *Value, BasicBlock *Default, unsigned NumCases,
                        Instruction *InsertBefore)
   : TerminatorInst(Type::getVoidTy(Value->getContext()), Instruction::Switch,
-                   0, 0, InsertBefore) {
+                   nullptr, 0, InsertBefore) {
   init(Value, Default, 2+NumCases*2);
 }
 
@@ -3372,12 +3372,12 @@ SwitchInst::SwitchInst(Value *Value, BasicBlock *Default, unsigned NumCases,
 SwitchInst::SwitchInst(Value *Value, BasicBlock *Default, unsigned NumCases,
                        BasicBlock *InsertAtEnd)
   : TerminatorInst(Type::getVoidTy(Value->getContext()), Instruction::Switch,
-                   0, 0, InsertAtEnd) {
+                   nullptr, 0, InsertAtEnd) {
   init(Value, Default, 2+NumCases*2);
 }
 
 SwitchInst::SwitchInst(const SwitchInst &SI)
-  : TerminatorInst(SI.getType(), Instruction::Switch, 0, 0) {
+  : TerminatorInst(SI.getType(), Instruction::Switch, nullptr, 0) {
   init(SI.getCondition(), SI.getDefaultDest(), SI.getNumOperands());
   NumOperands = SI.getNumOperands();
   Use *OL = OperandList, *InOL = SI.OperandList;
@@ -3425,8 +3425,8 @@ void SwitchInst::removeCase(CaseIt i) {
   }
 
   // Nuke the last value.
-  OL[NumOps-2].set(0);
-  OL[NumOps-2+1].set(0);
+  OL[NumOps-2].set(nullptr);
+  OL[NumOps-2+1].set(nullptr);
   NumOperands = NumOps-2;
 }
 
@@ -3492,14 +3492,14 @@ void IndirectBrInst::growOperands() {
 IndirectBrInst::IndirectBrInst(Value *Address, unsigned NumCases,
                                Instruction *InsertBefore)
 : TerminatorInst(Type::getVoidTy(Address->getContext()),Instruction::IndirectBr,
-                 0, 0, InsertBefore) {
+                 nullptr, 0, InsertBefore) {
   init(Address, NumCases);
 }
 
 IndirectBrInst::IndirectBrInst(Value *Address, unsigned NumCases,
                                BasicBlock *InsertAtEnd)
 : TerminatorInst(Type::getVoidTy(Address->getContext()),Instruction::IndirectBr,
-                 0, 0, InsertAtEnd) {
+                 nullptr, 0, InsertAtEnd) {
   init(Address, NumCases);
 }
 
@@ -3541,7 +3541,7 @@ void IndirectBrInst::removeDestination(unsigned idx) {
   OL[idx+1] = OL[NumOps-1];
   
   // Nuke the last value.
-  OL[NumOps-1].set(0);
+  OL[NumOps-1].set(nullptr);
   NumOperands = NumOps-1;
 }
 
@@ -3587,9 +3587,10 @@ InsertValueInst *InsertValueInst::clone_impl() const {
 }
 
 AllocaInst *AllocaInst::clone_impl() const {
-  return new AllocaInst(getAllocatedType(),
-                        (Value*)getOperand(0),
-                        getAlignment());
+  AllocaInst *Result = new AllocaInst(getAllocatedType(),
+                                      (Value *)getOperand(0), getAlignment());
+  Result->setUsedWithInAlloca(isUsedWithInAlloca());
+  return Result;
 }
 
 LoadInst *LoadInst::clone_impl() const {
diff --git a/lib/IR/IntrinsicInst.cpp b/lib/IR/IntrinsicInst.cpp
index 554f2be..5725284 100644
--- a/lib/IR/IntrinsicInst.cpp
+++ b/lib/IR/IntrinsicInst.cpp
@@ -35,7 +35,7 @@ static Value *CastOperand(Value *C) {
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
     if (CE->isCast())
       return CE->getOperand(0);
-  return NULL;
+  return nullptr;
 }
 
 Value *DbgInfoIntrinsic::StripCast(Value *C) {
@@ -57,7 +57,7 @@ Value *DbgDeclareInst::getAddress() const {
   if (MDNode* MD = cast_or_null<MDNode>(getArgOperand(0)))
     return MD->getOperand(0);
   else
-    return NULL;
+    return nullptr;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/IR/LLVMContext.cpp b/lib/IR/LLVMContext.cpp
index 1bfc515..de825f0 100644
--- a/lib/IR/LLVMContext.cpp
+++ b/lib/IR/LLVMContext.cpp
@@ -15,6 +15,7 @@
 #include "llvm/IR/LLVMContext.h"
 #include "LLVMContextImpl.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugLoc.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/Instruction.h"
@@ -114,6 +115,17 @@ void *LLVMContext::getDiagnosticContext() const {
   return pImpl->DiagnosticContext;
 }
 
+void LLVMContext::setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle)
+{
+  pImpl->YieldCallback = Callback;
+  pImpl->YieldOpaqueHandle = OpaqueHandle;
+}
+
+void LLVMContext::yield() {
+  if (pImpl->YieldCallback)
+    pImpl->YieldCallback(this, pImpl->YieldOpaqueHandle);
+}
+
 void LLVMContext::emitError(const Twine &ErrorStr) {
   diagnose(DiagnosticInfoInlineAsm(ErrorStr));
 }
@@ -125,10 +137,32 @@ void LLVMContext::emitError(const Instruction *I, const Twine &ErrorStr) {
 
 void LLVMContext::diagnose(const DiagnosticInfo &DI) {
   // If there is a report handler, use it.
-  if (pImpl->DiagnosticHandler != 0) {
+  if (pImpl->DiagnosticHandler) {
     pImpl->DiagnosticHandler(DI, pImpl->DiagnosticContext);
     return;
   }
+
+  // Optimization remarks are selective. They need to check whether the regexp
+  // pattern, passed via one of the -pass-remarks* flags, matches the name of
+  // the pass that is emitting the diagnostic. If there is no match, ignore the
+  // diagnostic and return.
+  switch (DI.getKind()) {
+  case llvm::DK_OptimizationRemark:
+    if (!cast<DiagnosticInfoOptimizationRemark>(DI).isEnabled())
+      return;
+    break;
+  case llvm::DK_OptimizationRemarkMissed:
+    if (!cast<DiagnosticInfoOptimizationRemarkMissed>(DI).isEnabled())
+      return;
+    break;
+  case llvm::DK_OptimizationRemarkAnalysis:
+    if (!cast<DiagnosticInfoOptimizationRemarkAnalysis>(DI).isEnabled())
+      return;
+    break;
+  default:
+    break;
+  }
+
   // Otherwise, print the message with a prefix based on the severity.
   std::string MsgStorage;
   raw_string_ostream Stream(MsgStorage);
diff --git a/lib/IR/LLVMContextImpl.cpp b/lib/IR/LLVMContextImpl.cpp
index ebff9d3..4c2791f 100644
--- a/lib/IR/LLVMContextImpl.cpp
+++ b/lib/IR/LLVMContextImpl.cpp
@@ -14,12 +14,13 @@
 #include "LLVMContextImpl.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/Attributes.h"
+#include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Module.h"
 #include <algorithm>
 using namespace llvm;
 
 LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
-  : TheTrueVal(0), TheFalseVal(0),
+  : TheTrueVal(nullptr), TheFalseVal(nullptr),
     VoidTy(C, Type::VoidTyID),
     LabelTy(C, Type::LabelTyID),
     HalfTy(C, Type::HalfTyID),
@@ -35,10 +36,12 @@ LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
     Int16Ty(C, 16),
     Int32Ty(C, 32),
     Int64Ty(C, 64) {
-  InlineAsmDiagHandler = 0;
-  InlineAsmDiagContext = 0;
-  DiagnosticHandler = 0;
-  DiagnosticContext = 0;
+  InlineAsmDiagHandler = nullptr;
+  InlineAsmDiagContext = nullptr;
+  DiagnosticHandler = nullptr;
+  DiagnosticContext = nullptr;
+  YieldCallback = nullptr;
+  YieldOpaqueHandle = nullptr;
   NamedStructTypesUniqueID = 0;
 }
 
@@ -46,8 +49,7 @@ namespace {
 struct DropReferences {
   // Takes the value_type of a ConstantUniqueMap's internal map, whose 'second'
   // is a Constant*.
-  template<typename PairT>
-  void operator()(const PairT &P) {
+  template <typename PairT> void operator()(const PairT &P) {
     P.second->dropAllReferences();
   }
 };
@@ -64,12 +66,11 @@ struct DropFirst {
 }
 
 LLVMContextImpl::~LLVMContextImpl() {
-  // NOTE: We need to delete the contents of OwnedModules, but we have to
-  // duplicate it into a temporary vector, because the destructor of Module
-  // will try to remove itself from OwnedModules set.  This would cause
-  // iterator invalidation if we iterated on the set directly.
-  std::vector<Module*> Modules(OwnedModules.begin(), OwnedModules.end());
-  DeleteContainerPointers(Modules);
+  // NOTE: We need to delete the contents of OwnedModules, but Module's dtor
+  // will call LLVMContextImpl::removeModule, thus invalidating iterators into
+  // the container. Avoid iterators during this operation:
+  while (!OwnedModules.empty())
+    delete *OwnedModules.begin();
   
   // Free the constants.  This is important to do here to ensure that they are
   // freed before the LeakDetector is torn down.
diff --git a/lib/IR/LLVMContextImpl.h b/lib/IR/LLVMContextImpl.h
index dc77d29..808c239 100644
--- a/lib/IR/LLVMContextImpl.h
+++ b/lib/IR/LLVMContextImpl.h
@@ -37,6 +37,9 @@ namespace llvm {
 
 class ConstantInt;
 class ConstantFP;
+class DiagnosticInfoOptimizationRemark;
+class DiagnosticInfoOptimizationRemarkMissed;
+class DiagnosticInfoOptimizationRemarkAnalysis;
 class LLVMContext;
 class Type;
 class Value;
@@ -56,8 +59,8 @@ struct DenseMapAPIntKeyInfo {
       return hash_combine(Key.type, Key.val);
     }
   };
-  static inline KeyTy getEmptyKey() { return KeyTy(APInt(1,0), 0); }
-  static inline KeyTy getTombstoneKey() { return KeyTy(APInt(1,1), 0); }
+  static inline KeyTy getEmptyKey() { return KeyTy(APInt(1,0), nullptr); }
+  static inline KeyTy getTombstoneKey() { return KeyTy(APInt(1,1), nullptr); }
   static unsigned getHashValue(const KeyTy &Key) {
     return static_cast<unsigned>(hash_value(Key));
   }
@@ -242,6 +245,9 @@ public:
   LLVMContext::DiagnosticHandlerTy DiagnosticHandler;
   void *DiagnosticContext;
 
+  LLVMContext::YieldCallbackTy YieldCallback;
+  void *YieldOpaqueHandle;
+
   typedef DenseMap<DenseMapAPIntKeyInfo::KeyTy, ConstantInt *,
                    DenseMapAPIntKeyInfo> IntMapTy;
   IntMapTy IntConstants;
diff --git a/lib/IR/LeaksContext.h b/lib/IR/LeaksContext.h
index 5038dc9..52ac170 100644
--- a/lib/IR/LeaksContext.h
+++ b/lib/IR/LeaksContext.h
@@ -12,8 +12,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_IR_LEAKSCONTEXT_H
+#define LLVM_IR_LEAKSCONTEXT_H
+
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/IR/Value.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
 
@@ -30,10 +34,10 @@ struct PrinterTrait<Value> {
 template <typename T>
 struct LeakDetectorImpl {
   explicit LeakDetectorImpl(const char* const name = "") : 
-    Cache(0), Name(name) { }
+    Cache(nullptr), Name(name) { }
 
   void clear() {
-    Cache = 0;
+    Cache = nullptr;
     Ts.clear();
   }
     
@@ -57,15 +61,15 @@ struct LeakDetectorImpl {
 
   void removeGarbage(const T* o) {
     if (o == Cache)
-      Cache = 0; // Cache hit
+      Cache = nullptr; // Cache hit
     else
       Ts.erase(o);
   }
 
   bool hasGarbage(const std::string& Message) {
-    addGarbage(0); // Flush the Cache
+    addGarbage(nullptr); // Flush the Cache
 
-    assert(Cache == 0 && "No value should be cached anymore!");
+    assert(!Cache && "No value should be cached anymore!");
 
     if (!Ts.empty()) {
       errs() << "Leaked " << Name << " objects found: " << Message << ":\n";
@@ -90,3 +94,5 @@ private:
 };
 
 }
+
+#endif // LLVM_IR_LEAKSCONTEXT_H
diff --git a/lib/IR/LegacyPassManager.cpp b/lib/IR/LegacyPassManager.cpp
index 7c5cc68..d3f3482 100644
--- a/lib/IR/LegacyPassManager.cpp
+++ b/lib/IR/LegacyPassManager.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/LegacyPassManagers.h"
@@ -22,6 +23,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Mutex.h"
+#include "llvm/Support/TimeValue.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
@@ -118,7 +120,7 @@ bool PMDataManager::isPassDebuggingExecutionsOrMore() const {
 
 
 void PassManagerPrettyStackEntry::print(raw_ostream &OS) const {
-  if (V == 0 && M == 0)
+  if (!V && !M)
     OS << "Releasing pass '";
   else
     OS << "Running pass '";
@@ -129,7 +131,7 @@ void PassManagerPrettyStackEntry::print(raw_ostream &OS) const {
     OS << " on module '" << M->getModuleIdentifier() << "'.\n";
     return;
   }
-  if (V == 0) {
+  if (!V) {
     OS << '\n';
     return;
   }
@@ -484,11 +486,11 @@ public:
   /// getPassTimer - Return the timer for the specified pass if it exists.
   Timer *getPassTimer(Pass *P) {
     if (P->getAsPMDataManager())
-      return 0;
+      return nullptr;
 
     sys::SmartScopedLock<true> Lock(*TimingInfoMutex);
     Timer *&T = TimingData[P];
-    if (T == 0)
+    if (!T)
       T = new Timer(P->getPassName(), TG);
     return T;
   }
@@ -579,7 +581,7 @@ void PMTopLevelManager::collectLastUses(SmallVectorImpl<Pass *> &LastUses,
 }
 
 AnalysisUsage *PMTopLevelManager::findAnalysisUsage(Pass *P) {
-  AnalysisUsage *AnUsage = NULL;
+  AnalysisUsage *AnUsage = nullptr;
   DenseMap<Pass *, AnalysisUsage *>::iterator DMI = AnUsageMap.find(P);
   if (DMI != AnUsageMap.end())
     AnUsage = DMI->second;
@@ -626,7 +628,7 @@ void PMTopLevelManager::schedulePass(Pass *P) {
       if (!AnalysisPass) {
         const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(*I);
 
-        if (PI == NULL) {
+        if (!PI) {
           // Pass P is not in the global PassRegistry
           dbgs() << "Pass '"  << P->getPassName() << "' is not initialized." << "\n";
           dbgs() << "Verify if there is a pass dependency cycle." << "\n";
@@ -733,7 +735,7 @@ Pass *PMTopLevelManager::findAnalysisPass(AnalysisID AID) {
     }
   }
 
-  return 0;
+  return nullptr;
 }
 
 // Print passes managed by this top level manager.
@@ -830,7 +832,7 @@ void PMDataManager::recordAvailableAnalysis(Pass *P) {
   // This pass is the current implementation of all of the interfaces it
   // implements as well.
   const PassInfo *PInf = PassRegistry::getPassRegistry()->getPassInfo(PI);
-  if (PInf == 0) return;
+  if (!PInf) return;
   const std::vector<const PassInfo*> &II = PInf->getInterfacesImplemented();
   for (unsigned i = 0, e = II.size(); i != e; ++i)
     AvailableAnalysis[II[i]->getTypeInfo()] = P;
@@ -847,7 +849,7 @@ bool PMDataManager::preserveHigherLevelAnalysis(Pass *P) {
   for (SmallVectorImpl<Pass *>::iterator I = HigherLevelAnalysis.begin(),
          E = HigherLevelAnalysis.end(); I  != E; ++I) {
     Pass *P1 = *I;
-    if (P1->getAsImmutablePass() == 0 &&
+    if (P1->getAsImmutablePass() == nullptr &&
         std::find(PreservedSet.begin(), PreservedSet.end(),
                   P1->getPassID()) ==
            PreservedSet.end())
@@ -887,7 +889,7 @@ void PMDataManager::removeNotPreservedAnalysis(Pass *P) {
   for (DenseMap<AnalysisID, Pass*>::iterator I = AvailableAnalysis.begin(),
          E = AvailableAnalysis.end(); I != E; ) {
     DenseMap<AnalysisID, Pass*>::iterator Info = I++;
-    if (Info->second->getAsImmutablePass() == 0 &&
+    if (Info->second->getAsImmutablePass() == nullptr &&
         std::find(PreservedSet.begin(), PreservedSet.end(), Info->first) ==
         PreservedSet.end()) {
       // Remove this analysis
@@ -911,7 +913,7 @@ void PMDataManager::removeNotPreservedAnalysis(Pass *P) {
            I = InheritedAnalysis[Index]->begin(),
            E = InheritedAnalysis[Index]->end(); I != E; ) {
       DenseMap<AnalysisID, Pass *>::iterator Info = I++;
-      if (Info->second->getAsImmutablePass() == 0 &&
+      if (Info->second->getAsImmutablePass() == nullptr &&
           std::find(PreservedSet.begin(), PreservedSet.end(), Info->first) ==
              PreservedSet.end()) {
         // Remove this analysis
@@ -1028,7 +1030,7 @@ void PMDataManager::add(Pass *P, bool ProcessAnalysis) {
   // Set P as P's last user until someone starts using P.
   // However, if P is a Pass Manager then it does not need
   // to record its last user.
-  if (P->getAsPMDataManager() == 0)
+  if (!P->getAsPMDataManager())
     LastUses.push_back(P);
   TPM->setLastUser(LastUses, P);
 
@@ -1095,7 +1097,7 @@ void PMDataManager::initializeAnalysisImpl(Pass *P) {
          I = AnUsage->getRequiredSet().begin(),
          E = AnUsage->getRequiredSet().end(); I != E; ++I) {
     Pass *Impl = findAnalysisPass(*I, true);
-    if (Impl == 0)
+    if (!Impl)
       // This may be analysis pass that is initialized on the fly.
       // If that is not the case then it will raise an assert when it is used.
       continue;
@@ -1119,7 +1121,7 @@ Pass *PMDataManager::findAnalysisPass(AnalysisID AID, bool SearchParent) {
   if (SearchParent)
     return TPM->findAnalysisPass(AID);
 
-  return NULL;
+  return nullptr;
 }
 
 // Print list of passes that are last used by P.
@@ -1158,7 +1160,8 @@ void PMDataManager::dumpPassInfo(Pass *P, enum PassDebuggingString S1,
                                  StringRef Msg) {
   if (PassDebugging < Executions)
     return;
-  dbgs() << (void*)this << std::string(getDepth()*2+1, ' ');
+  dbgs() << "[" << sys::TimeValue::now().str() << "] " << (void *)this
+         << std::string(getDepth() * 2 + 1, ' ');
   switch (S1) {
   case EXECUTION_MSG:
     dbgs() << "Executing Pass '" << P->getPassName();
@@ -1487,8 +1490,10 @@ bool FunctionPassManagerImpl::run(Function &F) {
   TimingInfo::createTheTimeInfo();
 
   initializeAllAnalysisInfo();
-  for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index)
+  for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
     Changed |= getContainedManager(Index)->runOnFunction(F);
+    F.getContext().yield();
+  }
 
   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index)
     getContainedManager(Index)->cleanup();
@@ -1657,6 +1662,8 @@ void MPPassManager::addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass) {
   assert((P->getPotentialPassManagerType() <
           RequiredPass->getPotentialPassManagerType()) &&
          "Unable to handle Pass that requires lower level Analysis pass");
+  if (!RequiredPass)
+    return;
 
   FunctionPassManagerImpl *FPP = OnTheFlyManagers[P];
   if (!FPP) {
@@ -1666,14 +1673,24 @@ void MPPassManager::addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass) {
 
     OnTheFlyManagers[P] = FPP;
   }
-  FPP->add(RequiredPass);
+  const PassInfo * RequiredPassPI =
+    PassRegistry::getPassRegistry()->getPassInfo(RequiredPass->getPassID());
 
-  // Register P as the last user of RequiredPass.
-  if (RequiredPass) {
-    SmallVector<Pass *, 1> LU;
-    LU.push_back(RequiredPass);
-    FPP->setLastUser(LU,  P);
+  Pass *FoundPass = nullptr;
+  if (RequiredPassPI && RequiredPassPI->isAnalysis()) {
+    FoundPass =
+      ((PMTopLevelManager*)FPP)->findAnalysisPass(RequiredPass->getPassID());
   }
+  if (!FoundPass) {
+    FoundPass = RequiredPass;
+    // This should be guaranteed to add RequiredPass to the passmanager given
+    // that we checked for an avaiable analysis above.
+    FPP->add(RequiredPass);
+  }
+  // Register P as the last user of FoundPass or RequiredPass.
+  SmallVector<Pass *, 1> LU;
+  LU.push_back(FoundPass);
+  FPP->setLastUser(LU,  P);
 }
 
 /// Return function pass corresponding to PassInfo PI, that is
@@ -1709,8 +1726,10 @@ bool PassManagerImpl::run(Module &M) {
   }
 
   initializeAllAnalysisInfo();
-  for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index)
+  for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
     Changed |= getContainedManager(Index)->runOnModule(M);
+    M.getContext().yield();
+  }
 
   for (SmallVectorImpl<ImmutablePass *>::const_iterator I = IPV.begin(),
        E = IPV.end(); I != E; ++I) {
@@ -1773,7 +1792,7 @@ void TimingInfo::createTheTimeInfo() {
 Timer *llvm::getPassTimer(Pass *P) {
   if (TheTimeInfo)
     return TheTimeInfo->getPassTimer(P);
-  return 0;
+  return nullptr;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/IR/MDBuilder.cpp b/lib/IR/MDBuilder.cpp
new file mode 100644
index 0000000..65cdf38
--- /dev/null
+++ b/lib/IR/MDBuilder.cpp
@@ -0,0 +1,139 @@
+//===---- llvm/MDBuilder.cpp - Builder for LLVM metadata ------------------===//
+//
+//                     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 MDBuilder class, which is used as a convenient way to
+// create LLVM metadata with a consistent and simplified interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Metadata.h"
+using namespace llvm;
+
+MDString *MDBuilder::createString(StringRef Str) {
+  return MDString::get(Context, Str);
+}
+
+MDNode *MDBuilder::createFPMath(float Accuracy) {
+  if (Accuracy == 0.0)
+    return nullptr;
+  assert(Accuracy > 0.0 && "Invalid fpmath accuracy!");
+  Value *Op = ConstantFP::get(Type::getFloatTy(Context), Accuracy);
+  return MDNode::get(Context, Op);
+}
+
+MDNode *MDBuilder::createBranchWeights(uint32_t TrueWeight,
+                                       uint32_t FalseWeight) {
+  uint32_t Weights[] = {TrueWeight, FalseWeight};
+  return createBranchWeights(Weights);
+}
+
+MDNode *MDBuilder::createBranchWeights(ArrayRef<uint32_t> Weights) {
+  assert(Weights.size() >= 2 && "Need at least two branch weights!");
+
+  SmallVector<Value *, 4> Vals(Weights.size() + 1);
+  Vals[0] = createString("branch_weights");
+
+  Type *Int32Ty = Type::getInt32Ty(Context);
+  for (unsigned i = 0, e = Weights.size(); i != e; ++i)
+    Vals[i + 1] = ConstantInt::get(Int32Ty, Weights[i]);
+
+  return MDNode::get(Context, Vals);
+}
+
+MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
+  assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
+  // If the range is everything then it is useless.
+  if (Hi == Lo)
+    return nullptr;
+
+  // Return the range [Lo, Hi).
+  Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
+  Value *Range[2] = {ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi)};
+  return MDNode::get(Context, Range);
+}
+
+MDNode *MDBuilder::createAnonymousTBAARoot() {
+  // To ensure uniqueness the root node is self-referential.
+  MDNode *Dummy = MDNode::getTemporary(Context, ArrayRef<Value *>());
+  MDNode *Root = MDNode::get(Context, Dummy);
+  // At this point we have
+  //   !0 = metadata !{}            <- dummy
+  //   !1 = metadata !{metadata !0} <- root
+  // Replace the dummy operand with the root node itself and delete the dummy.
+  Root->replaceOperandWith(0, Root);
+  MDNode::deleteTemporary(Dummy);
+  // We now have
+  //   !1 = metadata !{metadata !1} <- self-referential root
+  return Root;
+}
+
+MDNode *MDBuilder::createTBAARoot(StringRef Name) {
+  return MDNode::get(Context, createString(Name));
+}
+
+/// \brief Return metadata for a non-root TBAA node with the given name,
+/// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
+MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
+                                  bool isConstant) {
+  if (isConstant) {
+    Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
+    Value *Ops[3] = {createString(Name), Parent, Flags};
+    return MDNode::get(Context, Ops);
+  } else {
+    Value *Ops[2] = {createString(Name), Parent};
+    return MDNode::get(Context, Ops);
+  }
+}
+
+/// \brief Return metadata for a tbaa.struct node with the given
+/// struct field descriptions.
+MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
+  SmallVector<Value *, 4> Vals(Fields.size() * 3);
+  Type *Int64 = Type::getInt64Ty(Context);
+  for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
+    Vals[i * 3 + 0] = ConstantInt::get(Int64, Fields[i].Offset);
+    Vals[i * 3 + 1] = ConstantInt::get(Int64, Fields[i].Size);
+    Vals[i * 3 + 2] = Fields[i].TBAA;
+  }
+  return MDNode::get(Context, Vals);
+}
+
+/// \brief Return metadata for a TBAA struct node in the type DAG
+/// with the given name, a list of pairs (offset, field type in the type DAG).
+MDNode *MDBuilder::createTBAAStructTypeNode(
+    StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
+  SmallVector<Value *, 4> Ops(Fields.size() * 2 + 1);
+  Type *Int64 = Type::getInt64Ty(Context);
+  Ops[0] = createString(Name);
+  for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
+    Ops[i * 2 + 1] = Fields[i].first;
+    Ops[i * 2 + 2] = ConstantInt::get(Int64, Fields[i].second);
+  }
+  return MDNode::get(Context, Ops);
+}
+
+/// \brief Return metadata for a TBAA scalar type node with the
+/// given name, an offset and a parent in the TBAA type DAG.
+MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
+                                            uint64_t Offset) {
+  ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
+  Value *Ops[3] = {createString(Name), Parent, Off};
+  return MDNode::get(Context, Ops);
+}
+
+/// \brief Return metadata for a TBAA tag node with the given
+/// base type, access type and offset relative to the base type.
+MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
+                                           uint64_t Offset) {
+  Type *Int64 = Type::getInt64Ty(Context);
+  Value *Ops[3] = {BaseType, AccessType, ConstantInt::get(Int64, Offset)};
+  return MDNode::get(Context, Ops);
+}
diff --git a/lib/IR/Mangler.cpp b/lib/IR/Mangler.cpp
index d82388f..27d973b 100644
--- a/lib/IR/Mangler.cpp
+++ b/lib/IR/Mangler.cpp
@@ -108,7 +108,7 @@ void Mangler::getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV,
   }
 
   bool UseAt = false;
-  const Function *MSFunc = NULL;
+  const Function *MSFunc = nullptr;
   CallingConv::ID CC;
   if (DL->hasMicrosoftFastStdCallMangling()) {
     if ((MSFunc = dyn_cast<Function>(GV))) {
diff --git a/lib/IR/Metadata.cpp b/lib/IR/Metadata.cpp
index ba39334..4d932d0 100644
--- a/lib/IR/Metadata.cpp
+++ b/lib/IR/Metadata.cpp
@@ -87,7 +87,7 @@ public:
 MDNodeOperand::~MDNodeOperand() {}
 
 void MDNodeOperand::deleted() {
-  getParent()->replaceOperand(this, 0);
+  getParent()->replaceOperand(this, nullptr);
 }
 
 void MDNodeOperand::allUsesReplacedWith(Value *NV) {
@@ -148,10 +148,10 @@ MDNode::~MDNode() {
 }
 
 static const Function *getFunctionForValue(Value *V) {
-  if (!V) return NULL;
+  if (!V) return nullptr;
   if (Instruction *I = dyn_cast<Instruction>(V)) {
     BasicBlock *BB = I->getParent();
-    return BB ? BB->getParent() : 0;
+    return BB ? BB->getParent() : nullptr;
   }
   if (Argument *A = dyn_cast<Argument>(V))
     return A->getParent();
@@ -159,15 +159,15 @@ static const Function *getFunctionForValue(Value *V) {
     return BB->getParent();
   if (MDNode *MD = dyn_cast<MDNode>(V))
     return MD->getFunction();
-  return NULL;
+  return nullptr;
 }
 
 #ifndef NDEBUG
 static const Function *assertLocalFunction(const MDNode *N) {
-  if (!N->isFunctionLocal()) return 0;
+  if (!N->isFunctionLocal()) return nullptr;
 
   // FIXME: This does not handle cyclic function local metadata.
-  const Function *F = 0, *NewF = 0;
+  const Function *F = nullptr, *NewF = nullptr;
   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
     if (Value *V = N->getOperand(i)) {
       if (MDNode *MD = dyn_cast<MDNode>(V))
@@ -175,10 +175,11 @@ static const Function *assertLocalFunction(const MDNode *N) {
       else
         NewF = getFunctionForValue(V);
     }
-    if (F == 0)
+    if (!F)
       F = NewF;
-    else 
-      assert((NewF == 0 || F == NewF) &&"inconsistent function-local metadata");
+    else
+      assert((NewF == nullptr || F == NewF) &&
+             "inconsistent function-local metadata");
   }
   return F;
 }
@@ -192,11 +193,11 @@ const Function *MDNode::getFunction() const {
 #ifndef NDEBUG
   return assertLocalFunction(this);
 #else
-  if (!isFunctionLocal()) return NULL;
+  if (!isFunctionLocal()) return nullptr;
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
     if (const Function *F = getFunctionForValue(getOperand(i)))
       return F;
-  return NULL;
+  return nullptr;
 #endif
 }
 
@@ -335,14 +336,14 @@ void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
   // Likewise if the MDNode is function-local but for a different function.
   if (To && isFunctionLocalValue(To)) {
     if (!isFunctionLocal())
-      To = 0;
+      To = nullptr;
     else {
       const Function *F = getFunction();
       const Function *FV = getFunctionForValue(To);
       // Metadata can be function-local without having an associated function.
       // So only consider functions to have changed if non-null.
       if (F && FV && F != FV)
-        To = 0;
+        To = nullptr;
     }
   }
   
@@ -366,7 +367,7 @@ void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
   // anymore.  This commonly occurs during destruction, and uniquing these
   // brings little reuse.  Also, this means we don't need to include
   // isFunctionLocal bits in FoldingSetNodeIDs for MDNodes.
-  if (To == 0) {
+  if (!To) {
     setIsNotUniqued();
     return;
   }
@@ -407,7 +408,7 @@ void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
 
 MDNode *MDNode::getMostGenericFPMath(MDNode *A, MDNode *B) {
   if (!A || !B)
-    return NULL;
+    return nullptr;
 
   APFloat AVal = cast<ConstantFP>(A->getOperand(0))->getValueAPF();
   APFloat BVal = cast<ConstantFP>(B->getOperand(0))->getValueAPF();
@@ -457,7 +458,7 @@ MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
   // the ones that overlap.
 
   if (!A || !B)
-    return NULL;
+    return nullptr;
 
   if (A == B)
     return A;
@@ -512,7 +513,7 @@ MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
     ConstantRange Range(cast<ConstantInt>(EndPoints[0])->getValue(),
                         cast<ConstantInt>(EndPoints[1])->getValue());
     if (Range.isFullSet())
-      return NULL;
+      return nullptr;
   }
 
   return MDNode::get(A->getContext(), EndPoints);
@@ -527,7 +528,7 @@ static SmallVector<TrackingVH<MDNode>, 4> &getNMDOps(void *Operands) {
 }
 
 NamedMDNode::NamedMDNode(const Twine &N)
-  : Name(N.str()), Parent(0),
+  : Name(N.str()), Parent(nullptr),
     Operands(new SmallVector<TrackingVH<MDNode>, 4>()) {
 }
 
@@ -575,7 +576,7 @@ StringRef NamedMDNode::getName() const {
 //
 
 void Instruction::setMetadata(StringRef Kind, MDNode *Node) {
-  if (Node == 0 && !hasMetadata()) return;
+  if (!Node && !hasMetadata()) return;
   setMetadata(getContext().getMDKindID(Kind), Node);
 }
 
@@ -631,7 +632,7 @@ void Instruction::dropUnknownMetadata(ArrayRef<unsigned> KnownIDs) {
 /// node.  This updates/replaces metadata if already present, or removes it if
 /// Node is null.
 void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
-  if (Node == 0 && !hasMetadata()) return;
+  if (!Node && !hasMetadata()) return;
 
   // Handle 'dbg' as a special case since it is not stored in the hash table.
   if (KindID == LLVMContext::MD_dbg) {
@@ -691,7 +692,7 @@ MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
   if (KindID == LLVMContext::MD_dbg)
     return DbgLoc.getAsMDNode(getContext());
   
-  if (!hasMetadataHashEntry()) return 0;
+  if (!hasMetadataHashEntry()) return nullptr;
   
   LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
   assert(!Info.empty() && "bit out of sync with hash table");
@@ -699,7 +700,7 @@ MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
   for (const auto &I : Info)
     if (I.first == KindID)
       return I.second;
-  return 0;
+  return nullptr;
 }
 
 void Instruction::getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,
diff --git a/lib/IR/Module.cpp b/lib/IR/Module.cpp
index 1accd47..5dbed69 100644
--- a/lib/IR/Module.cpp
+++ b/lib/IR/Module.cpp
@@ -23,6 +23,7 @@
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/LeakDetector.h"
+#include "llvm/Support/Dwarf.h"
 #include <algorithm>
 #include <cstdarg>
 #include <cstdlib>
@@ -95,7 +96,7 @@ Constant *Module::getOrInsertFunction(StringRef Name,
                                       AttributeSet AttributeList) {
   // See if we have a definition for the specified function already.
   GlobalValue *F = getNamedValue(Name);
-  if (F == 0) {
+  if (!F) {
     // Nope, add it
     Function *New = Function::Create(Ty, GlobalVariable::ExternalLinkage, Name);
     if (!New->isIntrinsic())       // Intrinsics get attrs set on construction
@@ -183,7 +184,7 @@ GlobalVariable *Module::getGlobalVariable(StringRef Name, bool AllowLocal) {
       dyn_cast_or_null<GlobalVariable>(getNamedValue(Name)))
     if (AllowLocal || !Result->hasLocalLinkage())
       return Result;
-  return 0;
+  return nullptr;
 }
 
 /// getOrInsertGlobal - Look up the specified global in the module symbol table.
@@ -195,11 +196,11 @@ GlobalVariable *Module::getGlobalVariable(StringRef Name, bool AllowLocal) {
 Constant *Module::getOrInsertGlobal(StringRef Name, Type *Ty) {
   // See if we have a definition for the specified global already.
   GlobalVariable *GV = dyn_cast_or_null<GlobalVariable>(getNamedValue(Name));
-  if (GV == 0) {
+  if (!GV) {
     // Nope, add it
     GlobalVariable *New =
       new GlobalVariable(*this, Ty, false, GlobalVariable::ExternalLinkage,
-                         0, Name);
+                         nullptr, Name);
      return New;                    // Return the new declaration.
   }
 
@@ -284,7 +285,7 @@ Value *Module::getModuleFlag(StringRef Key) const {
     if (Key == MFE.Key->getString())
       return MFE.Val;
   }
-  return 0;
+  return nullptr;
 }
 
 /// getModuleFlagsMetadata - Returns the NamedMDNode in the module that
@@ -350,7 +351,7 @@ void Module::setDataLayout(const DataLayout *Other) {
 
 const DataLayout *Module::getDataLayout() const {
   if (DataLayoutStr.empty())
-    return 0;
+    return nullptr;
   return &DL;
 }
 
@@ -429,3 +430,10 @@ void Module::dropAllReferences() {
   for(Module::alias_iterator I = alias_begin(), E = alias_end(); I != E; ++I)
     I->dropAllReferences();
 }
+
+unsigned Module::getDwarfVersion() const {
+  Value *Val = getModuleFlag("Dwarf Version");
+  if (!Val)
+    return dwarf::DWARF_VERSION;
+  return cast<ConstantInt>(Val)->getZExtValue();
+}
diff --git a/lib/IR/Pass.cpp b/lib/IR/Pass.cpp
index e16c5b7..bb55d2a 100644
--- a/lib/IR/Pass.cpp
+++ b/lib/IR/Pass.cpp
@@ -22,6 +22,8 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+#define DEBUG_TYPE "ir"
+
 //===----------------------------------------------------------------------===//
 // Pass Implementation
 //
@@ -44,7 +46,7 @@ PassManagerType ModulePass::getPotentialPassManagerType() const {
 }
 
 bool Pass::mustPreserveAnalysisID(char &AID) const {
-  return Resolver->getAnalysisIfAvailable(&AID, true) != 0;
+  return Resolver->getAnalysisIfAvailable(&AID, true) != nullptr;
 }
 
 // dumpPassStructure - Implement the -debug-pass=Structure option
@@ -90,11 +92,11 @@ void *Pass::getAdjustedAnalysisPointer(AnalysisID AID) {
 }
 
 ImmutablePass *Pass::getAsImmutablePass() {
-  return 0;
+  return nullptr;
 }
 
 PMDataManager *Pass::getAsPMDataManager() {
-  return 0;
+  return nullptr;
 }
 
 void Pass::setResolver(AnalysisResolver *AR) {
@@ -112,7 +114,7 @@ void Pass::print(raw_ostream &O,const Module*) const {
 
 // dump - call print(cerr);
 void Pass::dump() const {
-  print(dbgs(), 0);
+  print(dbgs(), nullptr);
 }
 
 //===----------------------------------------------------------------------===//
@@ -193,7 +195,7 @@ const PassInfo *Pass::lookupPassInfo(StringRef Arg) {
 Pass *Pass::createPass(AnalysisID ID) {
   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(ID);
   if (!PI)
-    return NULL;
+    return nullptr;
   return PI->createPass();
 }
 
diff --git a/lib/IR/PassManager.cpp b/lib/IR/PassManager.cpp
index ea15455..0defb6a 100644
--- a/lib/IR/PassManager.cpp
+++ b/lib/IR/PassManager.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -32,6 +33,8 @@ PreservedAnalyses ModulePassManager::run(Module *M, ModuleAnalysisManager *AM) {
     if (AM)
       AM->invalidate(M, PassPA);
     PA.intersect(std::move(PassPA));
+
+    M->getContext().yield();
   }
 
   if (DebugPM)
@@ -59,7 +62,7 @@ ModuleAnalysisManager::ResultConceptT *
 ModuleAnalysisManager::getCachedResultImpl(void *PassID, Module *M) const {
   ModuleAnalysisResultMapT::const_iterator RI =
       ModuleAnalysisResults.find(PassID);
-  return RI == ModuleAnalysisResults.end() ? 0 : &*RI->second;
+  return RI == ModuleAnalysisResults.end() ? nullptr : &*RI->second;
 }
 
 void ModuleAnalysisManager::invalidateImpl(void *PassID, Module *M) {
@@ -92,6 +95,8 @@ PreservedAnalyses FunctionPassManager::run(Function *F,
     if (AM)
       AM->invalidate(F, PassPA);
     PA.intersect(std::move(PassPA));
+
+    F->getContext().yield();
   }
 
   if (DebugPM)
@@ -135,7 +140,7 @@ FunctionAnalysisManager::ResultConceptT *
 FunctionAnalysisManager::getCachedResultImpl(void *PassID, Function *F) const {
   FunctionAnalysisResultMapT::const_iterator RI =
       FunctionAnalysisResults.find(std::make_pair(PassID, F));
-  return RI == FunctionAnalysisResults.end() ? 0 : &*RI->second->second;
+  return RI == FunctionAnalysisResults.end() ? nullptr : &*RI->second->second;
 }
 
 void FunctionAnalysisManager::invalidateImpl(void *PassID, Function *F) {
@@ -165,6 +170,8 @@ void FunctionAnalysisManager::invalidateImpl(Function *F,
   while (!InvalidatedPassIDs.empty())
     FunctionAnalysisResults.erase(
         std::make_pair(InvalidatedPassIDs.pop_back_val(), F));
+  if (ResultsList.empty())
+    FunctionAnalysisResultLists.erase(F);
 }
 
 char FunctionAnalysisManagerModuleProxy::PassID;
diff --git a/lib/IR/PassRegistry.cpp b/lib/IR/PassRegistry.cpp
index 74dc0f1..6a5bee2 100644
--- a/lib/IR/PassRegistry.cpp
+++ b/lib/IR/PassRegistry.cpp
@@ -57,7 +57,7 @@ struct PassRegistryImpl {
   };
   DenseMap<const PassInfo*, AnalysisGroupInfo> AnalysisGroupInfoMap;
   
-  std::vector<const PassInfo*> ToFree;
+  std::vector<std::unique_ptr<const PassInfo>> ToFree;
   std::vector<PassRegistrationListener*> Listeners;
 };
 } // end anonymous namespace
@@ -75,20 +75,15 @@ void *PassRegistry::getImpl() const {
 PassRegistry::~PassRegistry() {
   sys::SmartScopedWriter<true> Guard(*Lock);
   PassRegistryImpl *Impl = static_cast<PassRegistryImpl*>(pImpl);
-  
-  for (std::vector<const PassInfo*>::iterator I = Impl->ToFree.begin(),
-       E = Impl->ToFree.end(); I != E; ++I)
-    delete *I;
-  
   delete Impl;
-  pImpl = 0;
+  pImpl = nullptr;
 }
 
 const PassInfo *PassRegistry::getPassInfo(const void *TI) const {
   sys::SmartScopedReader<true> Guard(*Lock);
   PassRegistryImpl *Impl = static_cast<PassRegistryImpl*>(getImpl());
   PassRegistryImpl::MapType::const_iterator I = Impl->PassInfoMap.find(TI);
-  return I != Impl->PassInfoMap.end() ? I->second : 0;
+  return I != Impl->PassInfoMap.end() ? I->second : nullptr;
 }
 
 const PassInfo *PassRegistry::getPassInfo(StringRef Arg) const {
@@ -96,7 +91,7 @@ const PassInfo *PassRegistry::getPassInfo(StringRef Arg) const {
   PassRegistryImpl *Impl = static_cast<PassRegistryImpl*>(getImpl());
   PassRegistryImpl::StringMapType::const_iterator
     I = Impl->PassInfoStringMap.find(Arg);
-  return I != Impl->PassInfoStringMap.end() ? I->second : 0;
+  return I != Impl->PassInfoStringMap.end() ? I->second : nullptr;
 }
 
 //===----------------------------------------------------------------------===//
@@ -117,7 +112,7 @@ void PassRegistry::registerPass(const PassInfo &PI, bool ShouldFree) {
        I = Impl->Listeners.begin(), E = Impl->Listeners.end(); I != E; ++I)
     (*I)->passRegistered(&PI);
   
-  if (ShouldFree) Impl->ToFree.push_back(&PI);
+  if (ShouldFree) Impl->ToFree.push_back(std::unique_ptr<const PassInfo>(&PI));
 }
 
 void PassRegistry::unregisterPass(const PassInfo &PI) {
@@ -148,7 +143,7 @@ void PassRegistry::registerAnalysisGroup(const void *InterfaceID,
                                          bool isDefault,
                                          bool ShouldFree) {
   PassInfo *InterfaceInfo =  const_cast<PassInfo*>(getPassInfo(InterfaceID));
-  if (InterfaceInfo == 0) {
+  if (!InterfaceInfo) {
     // First reference to Interface, register it now.
     registerPass(Registeree);
     InterfaceInfo = &Registeree;
@@ -174,7 +169,7 @@ void PassRegistry::registerAnalysisGroup(const void *InterfaceID,
            "Cannot add a pass to the same analysis group more than once!");
     AGI.Implementations.insert(ImplementationInfo);
     if (isDefault) {
-      assert(InterfaceInfo->getNormalCtor() == 0 &&
+      assert(InterfaceInfo->getNormalCtor() == nullptr &&
              "Default implementation for analysis group already specified!");
       assert(ImplementationInfo->getNormalCtor() &&
            "Cannot specify pass as default if it does not have a default ctor");
@@ -185,7 +180,8 @@ void PassRegistry::registerAnalysisGroup(const void *InterfaceID,
   }
   
   PassRegistryImpl *Impl = static_cast<PassRegistryImpl*>(getImpl());
-  if (ShouldFree) Impl->ToFree.push_back(&Registeree);
+  if (ShouldFree)
+    Impl->ToFree.push_back(std::unique_ptr<const PassInfo>(&Registeree));
 }
 
 void PassRegistry::addRegistrationListener(PassRegistrationListener *L) {
diff --git a/lib/IR/SymbolTableListTraitsImpl.h b/lib/IR/SymbolTableListTraitsImpl.h
index 5a383ee..8302597 100644
--- a/lib/IR/SymbolTableListTraitsImpl.h
+++ b/lib/IR/SymbolTableListTraitsImpl.h
@@ -65,7 +65,7 @@ void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 template<typename ValueSubClass, typename ItemParentClass>
 void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 ::addNodeToList(ValueSubClass *V) {
-  assert(V->getParent() == 0 && "Value already in a container!!");
+  assert(!V->getParent() && "Value already in a container!!");
   ItemParentClass *Owner = getListOwner();
   V->setParent(Owner);
   if (V->hasName())
@@ -76,7 +76,7 @@ void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 template<typename ValueSubClass, typename ItemParentClass>
 void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 ::removeNodeFromList(ValueSubClass *V) {
-  V->setParent(0);
+  V->setParent(nullptr);
   if (V->hasName())
     if (ValueSymbolTable *ST = TraitsClass::getSymTab(getListOwner()))
       ST->removeValueName(V->getValueName());
diff --git a/lib/IR/Type.cpp b/lib/IR/Type.cpp
index b02509f..1efde47 100644
--- a/lib/IR/Type.cpp
+++ b/lib/IR/Type.cpp
@@ -36,7 +36,7 @@ Type *Type::getPrimitiveType(LLVMContext &C, TypeID IDNumber) {
   case MetadataTyID  : return getMetadataTy(C);
   case X86_MMXTyID   : return getX86_MMXTy(C);
   default:
-    return 0;
+    return nullptr;
   }
 }
 
@@ -312,8 +312,8 @@ IntegerType *IntegerType::get(LLVMContext &C, unsigned NumBits) {
   }
   
   IntegerType *&Entry = C.pImpl->IntegerTypes[NumBits];
-  
-  if (Entry == 0)
+
+  if (!Entry)
     Entry = new (C.pImpl->TypeAllocator) IntegerType(C, NumBits);
   
   return Entry;
@@ -448,7 +448,7 @@ void StructType::setName(StringRef Name) {
     if (SymbolTableEntry) {
       // Delete the old string data.
       ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
-      SymbolTableEntry = 0;
+      SymbolTableEntry = nullptr;
     }
     return;
   }
@@ -497,7 +497,7 @@ StructType *StructType::get(LLVMContext &Context, bool isPacked) {
 }
 
 StructType *StructType::get(Type *type, ...) {
-  assert(type != 0 && "Cannot create a struct type with no elements with this");
+  assert(type && "Cannot create a struct type with no elements with this");
   LLVMContext &Ctx = type->getContext();
   va_list ap;
   SmallVector<llvm::Type*, 8> StructFields;
@@ -538,7 +538,7 @@ StructType *StructType::create(ArrayRef<Type*> Elements) {
 }
 
 StructType *StructType::create(StringRef Name, Type *type, ...) {
-  assert(type != 0 && "Cannot create a struct type with no elements with this");
+  assert(type && "Cannot create a struct type with no elements with this");
   LLVMContext &Ctx = type->getContext();
   va_list ap;
   SmallVector<llvm::Type*, 8> StructFields;
@@ -576,13 +576,13 @@ bool StructType::isSized(SmallPtrSet<const Type*, 4> *Visited) const {
 
 StringRef StructType::getName() const {
   assert(!isLiteral() && "Literal structs never have names");
-  if (SymbolTableEntry == 0) return StringRef();
-  
+  if (!SymbolTableEntry) return StringRef();
+
   return ((StringMapEntry<StructType*> *)SymbolTableEntry)->getKey();
 }
 
 void StructType::setBody(Type *type, ...) {
-  assert(type != 0 && "Cannot create a struct type with no elements with this");
+  assert(type && "Cannot create a struct type with no elements with this");
   va_list ap;
   SmallVector<llvm::Type*, 8> StructFields;
   va_start(ap, type);
@@ -680,8 +680,8 @@ ArrayType *ArrayType::get(Type *elementType, uint64_t NumElements) {
   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
   ArrayType *&Entry = 
     pImpl->ArrayTypes[std::make_pair(ElementType, NumElements)];
-  
-  if (Entry == 0)
+
+  if (!Entry)
     Entry = new (pImpl->TypeAllocator) ArrayType(ElementType, NumElements);
   return Entry;
 }
@@ -709,8 +709,8 @@ VectorType *VectorType::get(Type *elementType, unsigned NumElements) {
   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
   VectorType *&Entry = ElementType->getContext().pImpl
     ->VectorTypes[std::make_pair(ElementType, NumElements)];
-  
-  if (Entry == 0)
+
+  if (!Entry)
     Entry = new (pImpl->TypeAllocator) VectorType(ElementType, NumElements);
   return Entry;
 }
@@ -734,7 +734,7 @@ PointerType *PointerType::get(Type *EltTy, unsigned AddressSpace) {
   PointerType *&Entry = AddressSpace == 0 ? CImpl->PointerTypes[EltTy]
      : CImpl->ASPointerTypes[std::make_pair(EltTy, AddressSpace)];
 
-  if (Entry == 0)
+  if (!Entry)
     Entry = new (CImpl->TypeAllocator) PointerType(EltTy, AddressSpace);
   return Entry;
 }
diff --git a/lib/IR/Use.cpp b/lib/IR/Use.cpp
index 60a0c56..047861c 100644
--- a/lib/IR/Use.cpp
+++ b/lib/IR/Use.cpp
@@ -27,14 +27,14 @@ void Use::swap(Use &RHS) {
     Val = RHS.Val;
     Val->addUse(*this);
   } else {
-    Val = 0;
+    Val = nullptr;
   }
 
   if (OldVal) {
     RHS.Val = OldVal;
     RHS.Val->addUse(RHS);
   } else {
-    RHS.Val = 0;
+    RHS.Val = nullptr;
   }
 }
 
@@ -49,7 +49,7 @@ unsigned Use::getOperandNo() const {
   return this - getUser()->op_begin();
 }
 
-// Sets up the waymarking algoritm's tags for a series of Uses. See the
+// Sets up the waymarking algorithm's tags for a series of Uses. See the
 // algorithm details here:
 //
 //   http://www.llvm.org/docs/ProgrammersManual.html#UserLayout
diff --git a/lib/IR/Value.cpp b/lib/IR/Value.cpp
index 97a562e..d734e4e 100644
--- a/lib/IR/Value.cpp
+++ b/lib/IR/Value.cpp
@@ -44,7 +44,7 @@ static inline Type *checkType(Type *Ty) {
 Value::Value(Type *ty, unsigned scid)
   : SubclassID(scid), HasValueHandle(0),
     SubclassOptionalData(0), SubclassData(0), VTy((Type*)checkType(ty)),
-    UseList(0), Name(0) {
+    UseList(nullptr), Name(nullptr) {
   // FIXME: Why isn't this in the subclass gunk??
   // Note, we cannot call isa<CallInst> before the CallInst has been
   // constructed.
@@ -141,7 +141,7 @@ unsigned Value::getNumUses() const {
 }
 
 static bool getSymTab(Value *V, ValueSymbolTable *&ST) {
-  ST = 0;
+  ST = nullptr;
   if (Instruction *I = dyn_cast<Instruction>(V)) {
     if (BasicBlock *P = I->getParent())
       if (Function *PP = P->getParent())
@@ -203,7 +203,7 @@ void Value::setName(const Twine &NewName) {
     if (NameRef.empty()) {
       // Free the name for this value.
       Name->Destroy();
-      Name = 0;
+      Name = nullptr;
       return;
     }
 
@@ -225,7 +225,7 @@ void Value::setName(const Twine &NewName) {
     // Remove old name.
     ST->removeValueName(Name);
     Name->Destroy();
-    Name = 0;
+    Name = nullptr;
 
     if (NameRef.empty())
       return;
@@ -241,7 +241,7 @@ void Value::setName(const Twine &NewName) {
 void Value::takeName(Value *V) {
   assert(SubclassID != MDStringVal && "Cannot take the name of an MDString!");
 
-  ValueSymbolTable *ST = 0;
+  ValueSymbolTable *ST = nullptr;
   // If this value has a name, drop it.
   if (hasName()) {
     // Get the symtab this is in.
@@ -256,7 +256,7 @@ void Value::takeName(Value *V) {
     if (ST)
       ST->removeValueName(Name);
     Name->Destroy();
-    Name = 0;
+    Name = nullptr;
   }
 
   // Now we know that this has no name.
@@ -283,7 +283,7 @@ void Value::takeName(Value *V) {
   if (ST == VST) {
     // Take the name!
     Name = V->Name;
-    V->Name = 0;
+    V->Name = nullptr;
     Name->setValue(this);
     return;
   }
@@ -294,17 +294,73 @@ void Value::takeName(Value *V) {
   if (VST)
     VST->removeValueName(V->Name);
   Name = V->Name;
-  V->Name = 0;
+  V->Name = nullptr;
   Name->setValue(this);
 
   if (ST)
     ST->reinsertValue(this);
 }
 
+static GlobalObject &findReplacementForAliasUse(Value &C) {
+  if (auto *GO = dyn_cast<GlobalObject>(&C))
+    return *GO;
+  if (auto *GA = dyn_cast<GlobalAlias>(&C))
+    return *GA->getAliasee();
+  auto *CE = cast<ConstantExpr>(&C);
+  assert(CE->getOpcode() == Instruction::BitCast ||
+         CE->getOpcode() == Instruction::GetElementPtr ||
+         CE->getOpcode() == Instruction::AddrSpaceCast);
+  if (CE->getOpcode() == Instruction::GetElementPtr)
+    assert(cast<GEPOperator>(CE)->hasAllZeroIndices());
+  return findReplacementForAliasUse(*CE->getOperand(0));
+}
+
+static void replaceAliasUseWith(Use &U, Value *New) {
+  GlobalObject &Replacement = findReplacementForAliasUse(*New);
+  assert(&cast<GlobalObject>(*U) != &Replacement &&
+         "replaceAliasUseWith cannot form an alias cycle");
+  U.set(&Replacement);
+}
+
+#ifndef NDEBUG
+static bool contains(SmallPtrSet<ConstantExpr *, 4> &Cache, ConstantExpr *Expr,
+                     Constant *C) {
+  if (!Cache.insert(Expr))
+    return false;
+
+  for (auto &O : Expr->operands()) {
+    if (O == C)
+      return true;
+    auto *CE = dyn_cast<ConstantExpr>(O);
+    if (!CE)
+      continue;
+    if (contains(Cache, CE, C))
+      return true;
+  }
+  return false;
+}
+
+static bool contains(Value *Expr, Value *V) {
+  if (Expr == V)
+    return true;
+
+  auto *C = dyn_cast<Constant>(V);
+  if (!C)
+    return false;
+
+  auto *CE = dyn_cast<ConstantExpr>(Expr);
+  if (!CE)
+    return false;
+
+  SmallPtrSet<ConstantExpr *, 4> Cache;
+  return contains(Cache, CE, C);
+}
+#endif
 
 void Value::replaceAllUsesWith(Value *New) {
   assert(New && "Value::replaceAllUsesWith(<null>) is invalid!");
-  assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!");
+  assert(!contains(New, this) &&
+         "this->replaceAllUsesWith(expr(this)) is NOT valid!");
   assert(New->getType() == getType() &&
          "replaceAllUses of value with new value of different type!");
 
@@ -316,7 +372,11 @@ void Value::replaceAllUsesWith(Value *New) {
     Use &U = *UseList;
     // Must handle Constants specially, we cannot call replaceUsesOfWith on a
     // constant because they are uniqued.
-    if (Constant *C = dyn_cast<Constant>(U.getUser())) {
+    if (auto *C = dyn_cast<Constant>(U.getUser())) {
+      if (isa<GlobalAlias>(C)) {
+        replaceAliasUseWith(U, New);
+        continue;
+      }
       if (!isa<GlobalValue>(C)) {
         C->replaceUsesOfWithOnConstant(this, New, &U);
         continue;
@@ -557,7 +617,7 @@ void ValueHandleBase::AddToUseList() {
     // If this value already has a ValueHandle, then it must be in the
     // ValueHandles map already.
     ValueHandleBase *&Entry = pImpl->ValueHandles[VP.getPointer()];
-    assert(Entry != 0 && "Value doesn't have any handles?");
+    assert(Entry && "Value doesn't have any handles?");
     AddToExistingUseList(&Entry);
     return;
   }
@@ -571,7 +631,7 @@ void ValueHandleBase::AddToUseList() {
   const void *OldBucketPtr = Handles.getPointerIntoBucketsArray();
 
   ValueHandleBase *&Entry = Handles[VP.getPointer()];
-  assert(Entry == 0 && "Value really did already have handles?");
+  assert(!Entry && "Value really did already have handles?");
   AddToExistingUseList(&Entry);
   VP.getPointer()->HasValueHandle = true;
 
@@ -652,7 +712,7 @@ void ValueHandleBase::ValueIsDeleted(Value *V) {
       break;
     case Weak:
       // Weak just goes to null, which will unlink it from the list.
-      Entry->operator=(0);
+      Entry->operator=(nullptr);
       break;
     case Callback:
       // Forward to the subclass's implementation.
diff --git a/lib/IR/ValueSymbolTable.cpp b/lib/IR/ValueSymbolTable.cpp
index fffacb3..e9e979a 100644
--- a/lib/IR/ValueSymbolTable.cpp
+++ b/lib/IR/ValueSymbolTable.cpp
@@ -11,7 +11,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "valuesymtab"
 #include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/IR/GlobalValue.h"
@@ -20,6 +19,8 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+#define DEBUG_TYPE "valuesymtab"
+
 // Class destructor
 ValueSymbolTable::~ValueSymbolTable() {
 #ifndef NDEBUG   // Only do this in -g mode...
@@ -56,7 +57,7 @@ void ValueSymbolTable::reinsertValue(Value* V) {
 
     // Try insert the vmap entry with this suffix.
     ValueName &NewName = vmap.GetOrCreateValue(UniqueName);
-    if (NewName.getValue() == 0) {
+    if (!NewName.getValue()) {
       // Newly inserted name.  Success!
       NewName.setValue(V);
       V->Name = &NewName;
@@ -78,7 +79,7 @@ void ValueSymbolTable::removeValueName(ValueName *V) {
 ValueName *ValueSymbolTable::createValueName(StringRef Name, Value *V) {
   // In the common case, the name is not already in the symbol table.
   ValueName &Entry = vmap.GetOrCreateValue(Name);
-  if (Entry.getValue() == 0) {
+  if (!Entry.getValue()) {
     Entry.setValue(V);
     //DEBUG(dbgs() << " Inserted value: " << Entry.getKeyData() << ": "
     //           << *V << "\n");
@@ -95,7 +96,7 @@ ValueName *ValueSymbolTable::createValueName(StringRef Name, Value *V) {
     
     // Try insert the vmap entry with this suffix.
     ValueName &NewName = vmap.GetOrCreateValue(UniqueName);
-    if (NewName.getValue() == 0) {
+    if (!NewName.getValue()) {
       // Newly inserted name.  Success!
       NewName.setValue(V);
      //DEBUG(dbgs() << " Inserted value: " << UniqueName << ": " << *V << "\n");
diff --git a/lib/IR/Verifier.cpp b/lib/IR/Verifier.cpp
index 089ad1c..bcc38c1 100644
--- a/lib/IR/Verifier.cpp
+++ b/lib/IR/Verifier.cpp
@@ -61,6 +61,7 @@
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/InstIterator.h"
 #include "llvm/IR/InstVisitor.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/LLVMContext.h"
@@ -76,15 +77,71 @@
 #include <cstdarg>
 using namespace llvm;
 
-static cl::opt<bool> DisableDebugInfoVerifier("disable-debug-info-verifier",
-                                              cl::init(true));
+static cl::opt<bool> VerifyDebugInfo("verify-debug-info", cl::init(false));
 
 namespace {
-class Verifier : public InstVisitor<Verifier> {
-  friend class InstVisitor<Verifier>;
-
+struct VerifierSupport {
   raw_ostream &OS;
   const Module *M;
+
+  /// \brief Track the brokenness of the module while recursively visiting.
+  bool Broken;
+
+  explicit VerifierSupport(raw_ostream &OS)
+      : OS(OS), M(nullptr), Broken(false) {}
+
+  void WriteValue(const Value *V) {
+    if (!V)
+      return;
+    if (isa<Instruction>(V)) {
+      OS << *V << '\n';
+    } else {
+      V->printAsOperand(OS, true, M);
+      OS << '\n';
+    }
+  }
+
+  void WriteType(Type *T) {
+    if (!T)
+      return;
+    OS << ' ' << *T;
+  }
+
+  // CheckFailed - A check failed, so print out the condition and the message
+  // that failed.  This provides a nice place to put a breakpoint if you want
+  // to see why something is not correct.
+  void CheckFailed(const Twine &Message, const Value *V1 = nullptr,
+                   const Value *V2 = nullptr, const Value *V3 = nullptr,
+                   const Value *V4 = nullptr) {
+    OS << Message.str() << "\n";
+    WriteValue(V1);
+    WriteValue(V2);
+    WriteValue(V3);
+    WriteValue(V4);
+    Broken = true;
+  }
+
+  void CheckFailed(const Twine &Message, const Value *V1, Type *T2,
+                   const Value *V3 = nullptr) {
+    OS << Message.str() << "\n";
+    WriteValue(V1);
+    WriteType(T2);
+    WriteValue(V3);
+    Broken = true;
+  }
+
+  void CheckFailed(const Twine &Message, Type *T1, Type *T2 = nullptr,
+                   Type *T3 = nullptr) {
+    OS << Message.str() << "\n";
+    WriteType(T1);
+    WriteType(T2);
+    WriteType(T3);
+    Broken = true;
+  }
+};
+class Verifier : public InstVisitor<Verifier>, VerifierSupport {
+  friend class InstVisitor<Verifier>;
+
   LLVMContext *Context;
   const DataLayout *DL;
   DominatorTree DT;
@@ -104,15 +161,10 @@ class Verifier : public InstVisitor<Verifier> {
   /// personality function.
   const Value *PersonalityFn;
 
-  /// \brief Finder keeps track of all debug info MDNodes in a Module.
-  DebugInfoFinder Finder;
-
-  /// \brief Track the brokenness of the module while recursively visiting.
-  bool Broken;
-
 public:
   explicit Verifier(raw_ostream &OS = dbgs())
-      : OS(OS), M(0), Context(0), DL(0), PersonalityFn(0), Broken(false) {}
+      : VerifierSupport(OS), Context(nullptr), DL(nullptr),
+        PersonalityFn(nullptr) {}
 
   bool verify(const Function &F) {
     M = F.getParent();
@@ -142,16 +194,11 @@ public:
     // FIXME: It's really gross that we have to cast away constness here.
     DT.recalculate(const_cast<Function &>(F));
 
-    Finder.reset();
     Broken = false;
     // FIXME: We strip const here because the inst visitor strips const.
     visit(const_cast<Function &>(F));
     InstsInThisBlock.clear();
-    PersonalityFn = 0;
-
-    if (!DisableDebugInfoVerifier)
-      // Verify Debug Info.
-      verifyDebugInfo();
+    PersonalityFn = nullptr;
 
     return !Broken;
   }
@@ -159,7 +206,6 @@ public:
   bool verify(const Module &M) {
     this->M = &M;
     Context = &M.getContext();
-    Finder.reset();
     Broken = false;
 
     // Scan through, checking all of the external function's linkage now...
@@ -187,13 +233,6 @@ public:
     visitModuleFlags(M);
     visitModuleIdents(M);
 
-    if (!DisableDebugInfoVerifier) {
-      Finder.reset();
-      Finder.processModule(M);
-      // Verify Debug Info.
-      verifyDebugInfo();
-    }
-
     return !Broken;
   }
 
@@ -262,6 +301,7 @@ private:
   void visitLandingPadInst(LandingPadInst &LPI);
 
   void VerifyCallSite(CallSite CS);
+  void verifyMustTailCall(CallInst &CI);
   bool PerformTypeCheck(Intrinsic::ID ID, Function *F, Type *Ty, int VT,
                         unsigned ArgNo, std::string &Suffix);
   bool VerifyIntrinsicType(Type *Ty, ArrayRef<Intrinsic::IITDescriptor> &Infos,
@@ -278,56 +318,21 @@ private:
 
   void VerifyBitcastType(const Value *V, Type *DestTy, Type *SrcTy);
   void VerifyConstantExprBitcastType(const ConstantExpr *CE);
+};
+class DebugInfoVerifier : public VerifierSupport {
+public:
+  explicit DebugInfoVerifier(raw_ostream &OS = dbgs()) : VerifierSupport(OS) {}
 
-  void verifyDebugInfo();
-
-  void WriteValue(const Value *V) {
-    if (!V)
-      return;
-    if (isa<Instruction>(V)) {
-      OS << *V << '\n';
-    } else {
-      V->printAsOperand(OS, true, M);
-      OS << '\n';
-    }
-  }
-
-  void WriteType(Type *T) {
-    if (!T)
-      return;
-    OS << ' ' << *T;
-  }
-
-  // CheckFailed - A check failed, so print out the condition and the message
-  // that failed.  This provides a nice place to put a breakpoint if you want
-  // to see why something is not correct.
-  void CheckFailed(const Twine &Message, const Value *V1 = 0,
-                   const Value *V2 = 0, const Value *V3 = 0,
-                   const Value *V4 = 0) {
-    OS << Message.str() << "\n";
-    WriteValue(V1);
-    WriteValue(V2);
-    WriteValue(V3);
-    WriteValue(V4);
-    Broken = true;
-  }
-
-  void CheckFailed(const Twine &Message, const Value *V1, Type *T2,
-                   const Value *V3 = 0) {
-    OS << Message.str() << "\n";
-    WriteValue(V1);
-    WriteType(T2);
-    WriteValue(V3);
-    Broken = true;
+  bool verify(const Module &M) {
+    this->M = &M;
+    verifyDebugInfo();
+    return !Broken;
   }
 
-  void CheckFailed(const Twine &Message, Type *T1, Type *T2 = 0, Type *T3 = 0) {
-    OS << Message.str() << "\n";
-    WriteType(T1);
-    WriteType(T2);
-    WriteType(T3);
-    Broken = true;
-  }
+private:
+  void verifyDebugInfo();
+  void processInstructions(DebugInfoFinder &Finder);
+  void processCallInst(DebugInfoFinder &Finder, const CallInst &CI);
 };
 } // End anonymous namespace
 
@@ -345,18 +350,14 @@ private:
 
 void Verifier::visit(Instruction &I) {
   for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
-    Assert1(I.getOperand(i) != 0, "Operand is null", &I);
+    Assert1(I.getOperand(i) != nullptr, "Operand is null", &I);
   InstVisitor<Verifier>::visit(I);
 }
 
 
 void Verifier::visitGlobalValue(const GlobalValue &GV) {
-  Assert1(!GV.isDeclaration() ||
-          GV.isMaterializable() ||
-          GV.hasExternalLinkage() ||
-          GV.hasExternalWeakLinkage() ||
-          (isa<GlobalAlias>(GV) &&
-           (GV.hasLocalLinkage() || GV.hasWeakLinkage())),
+  Assert1(!GV.isDeclaration() || GV.isMaterializable() ||
+              GV.hasExternalLinkage() || GV.hasExternalWeakLinkage(),
           "Global is external, but doesn't have external or weak linkage!",
           &GV);
 
@@ -395,14 +396,22 @@ void Verifier::visitGlobalVariable(const GlobalVariable &GV) {
             "invalid linkage for intrinsic global variable", &GV);
     // Don't worry about emitting an error for it not being an array,
     // visitGlobalValue will complain on appending non-array.
-    if (ArrayType *ATy = dyn_cast<ArrayType>(GV.getType())) {
+    if (ArrayType *ATy = dyn_cast<ArrayType>(GV.getType()->getElementType())) {
       StructType *STy = dyn_cast<StructType>(ATy->getElementType());
       PointerType *FuncPtrTy =
           FunctionType::get(Type::getVoidTy(*Context), false)->getPointerTo();
-      Assert1(STy && STy->getNumElements() == 2 &&
+      // FIXME: Reject the 2-field form in LLVM 4.0.
+      Assert1(STy && (STy->getNumElements() == 2 ||
+                      STy->getNumElements() == 3) &&
               STy->getTypeAtIndex(0u)->isIntegerTy(32) &&
               STy->getTypeAtIndex(1) == FuncPtrTy,
               "wrong type for intrinsic global variable", &GV);
+      if (STy->getNumElements() == 3) {
+        Type *ETy = STy->getTypeAtIndex(2);
+        Assert1(ETy->isPointerTy() &&
+                    cast<PointerType>(ETy)->getElementType()->isIntegerTy(8),
+                "wrong type for intrinsic global variable", &GV);
+      }
     }
   }
 
@@ -472,11 +481,7 @@ void Verifier::visitGlobalAlias(const GlobalAlias &GA) {
           "Alias should have external or external weak linkage!", &GA);
   Assert1(GA.getAliasee(),
           "Aliasee cannot be NULL!", &GA);
-  Assert1(GA.getType() == GA.getAliasee()->getType(),
-          "Alias and aliasee types should match!", &GA);
   Assert1(!GA.hasUnnamedAddr(), "Alias cannot have unnamed_addr!", &GA);
-  Assert1(!GA.hasSection(), "Alias cannot have a section!", &GA);
-  Assert1(!GA.getAlignment(), "Alias connot have an alignment", &GA);
 
   const Constant *Aliasee = GA.getAliasee();
   const GlobalValue *GV = dyn_cast<GlobalValue>(Aliasee);
@@ -492,14 +497,7 @@ void Verifier::visitGlobalAlias(const GlobalAlias &GA) {
                 "addrspacecast of GlobalValue",
             &GA);
 
-    if (CE->getOpcode() == Instruction::BitCast) {
-      unsigned SrcAS = GV->getType()->getPointerAddressSpace();
-      unsigned DstAS = CE->getType()->getPointerAddressSpace();
-
-      Assert1(SrcAS == DstAS,
-              "Alias bitcasts cannot be between different address spaces",
-              &GA);
-    }
+    VerifyConstantExprBitcastType(CE);
   }
   Assert1(!GV->isDeclaration(), "Alias must point to a definition", &GA);
   if (const GlobalAlias *GAAliasee = dyn_cast<GlobalAlias>(GV)) {
@@ -507,10 +505,6 @@ void Verifier::visitGlobalAlias(const GlobalAlias &GA) {
             &GA);
   }
 
-  const GlobalValue *AG = GA.getAliasedGlobal();
-  Assert1(AG, "Aliasing chain should end with function or global variable",
-          &GA);
-
   visitGlobalValue(GA);
 }
 
@@ -522,7 +516,7 @@ void Verifier::visitNamedMDNode(const NamedMDNode &NMD) {
 
     Assert1(!MD->isFunctionLocal(),
             "Named metadata operand cannot be function local!", MD);
-    visitMDNode(*MD, 0);
+    visitMDNode(*MD, nullptr);
   }
 }
 
@@ -548,7 +542,7 @@ void Verifier::visitMDNode(MDNode &MD, Function *F) {
 
     // If this was an instruction, bb, or argument, verify that it is in the
     // function that we expect.
-    Function *ActualF = 0;
+    Function *ActualF = nullptr;
     if (Instruction *I = dyn_cast<Instruction>(Op))
       ActualF = I->getParent()->getParent();
     else if (BasicBlock *BB = dyn_cast<BasicBlock>(Op))
@@ -821,6 +815,7 @@ void Verifier::VerifyFunctionAttrs(FunctionType *FT, AttributeSet Attrs,
 
   bool SawNest = false;
   bool SawReturned = false;
+  bool SawSRet = false;
 
   for (unsigned i = 0, e = Attrs.getNumSlots(); i != e; ++i) {
     unsigned Idx = Attrs.getSlotIndex(i);
@@ -851,8 +846,12 @@ void Verifier::VerifyFunctionAttrs(FunctionType *FT, AttributeSet Attrs,
       SawReturned = true;
     }
 
-    if (Attrs.hasAttribute(Idx, Attribute::StructRet))
-      Assert1(Idx == 1, "Attribute sret is not on first parameter!", V);
+    if (Attrs.hasAttribute(Idx, Attribute::StructRet)) {
+      Assert1(!SawSRet, "Cannot have multiple 'sret' parameters!", V);
+      Assert1(Idx == 1 || Idx == 2,
+              "Attribute 'sret' is not on first or second parameter!", V);
+      SawSRet = true;
+    }
 
     if (Attrs.hasAttribute(Idx, Attribute::InAlloca)) {
       Assert1(Idx == FT->getNumParams(),
@@ -1489,6 +1488,16 @@ void Verifier::VerifyCallSite(CallSite CS) {
   // Verify call attributes.
   VerifyFunctionAttrs(FTy, Attrs, I);
 
+  // Conservatively check the inalloca argument.
+  // We have a bug if we can find that there is an underlying alloca without
+  // inalloca.
+  if (CS.hasInAllocaArgument()) {
+    Value *InAllocaArg = CS.getArgument(FTy->getNumParams() - 1);
+    if (auto AI = dyn_cast<AllocaInst>(InAllocaArg->stripInBoundsOffsets()))
+      Assert2(AI->isUsedWithInAlloca(),
+              "inalloca argument for call has mismatched alloca", AI, I);
+  }
+
   if (FTy->isVarArg()) {
     // FIXME? is 'nest' even legal here?
     bool SawNest = false;
@@ -1530,7 +1539,7 @@ void Verifier::VerifyCallSite(CallSite CS) {
   }
 
   // Verify that there's no metadata unless it's a direct call to an intrinsic.
-  if (CS.getCalledFunction() == 0 ||
+  if (CS.getCalledFunction() == nullptr ||
       !CS.getCalledFunction()->getName().startswith("llvm.")) {
     for (FunctionType::param_iterator PI = FTy->param_begin(),
            PE = FTy->param_end(); PI != PE; ++PI)
@@ -1541,9 +1550,102 @@ void Verifier::VerifyCallSite(CallSite CS) {
   visitInstruction(*I);
 }
 
+/// Two types are "congruent" if they are identical, or if they are both pointer
+/// types with different pointee types and the same address space.
+static bool isTypeCongruent(Type *L, Type *R) {
+  if (L == R)
+    return true;
+  PointerType *PL = dyn_cast<PointerType>(L);
+  PointerType *PR = dyn_cast<PointerType>(R);
+  if (!PL || !PR)
+    return false;
+  return PL->getAddressSpace() == PR->getAddressSpace();
+}
+
+static AttrBuilder getParameterABIAttributes(int I, AttributeSet Attrs) {
+  static const Attribute::AttrKind ABIAttrs[] = {
+      Attribute::StructRet, Attribute::ByVal, Attribute::InAlloca,
+      Attribute::InReg, Attribute::Returned};
+  AttrBuilder Copy;
+  for (auto AK : ABIAttrs) {
+    if (Attrs.hasAttribute(I + 1, AK))
+      Copy.addAttribute(AK);
+  }
+  if (Attrs.hasAttribute(I + 1, Attribute::Alignment))
+    Copy.addAlignmentAttr(Attrs.getParamAlignment(I + 1));
+  return Copy;
+}
+
+void Verifier::verifyMustTailCall(CallInst &CI) {
+  Assert1(!CI.isInlineAsm(), "cannot use musttail call with inline asm", &CI);
+
+  // - The caller and callee prototypes must match.  Pointer types of
+  //   parameters or return types may differ in pointee type, but not
+  //   address space.
+  Function *F = CI.getParent()->getParent();
+  auto GetFnTy = [](Value *V) {
+    return cast<FunctionType>(
+        cast<PointerType>(V->getType())->getElementType());
+  };
+  FunctionType *CallerTy = GetFnTy(F);
+  FunctionType *CalleeTy = GetFnTy(CI.getCalledValue());
+  Assert1(CallerTy->getNumParams() == CalleeTy->getNumParams(),
+          "cannot guarantee tail call due to mismatched parameter counts", &CI);
+  Assert1(CallerTy->isVarArg() == CalleeTy->isVarArg(),
+          "cannot guarantee tail call due to mismatched varargs", &CI);
+  Assert1(isTypeCongruent(CallerTy->getReturnType(), CalleeTy->getReturnType()),
+          "cannot guarantee tail call due to mismatched return types", &CI);
+  for (int I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
+    Assert1(
+        isTypeCongruent(CallerTy->getParamType(I), CalleeTy->getParamType(I)),
+        "cannot guarantee tail call due to mismatched parameter types", &CI);
+  }
+
+  // - The calling conventions of the caller and callee must match.
+  Assert1(F->getCallingConv() == CI.getCallingConv(),
+          "cannot guarantee tail call due to mismatched calling conv", &CI);
+
+  // - All ABI-impacting function attributes, such as sret, byval, inreg,
+  //   returned, and inalloca, must match.
+  AttributeSet CallerAttrs = F->getAttributes();
+  AttributeSet CalleeAttrs = CI.getAttributes();
+  for (int I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
+    AttrBuilder CallerABIAttrs = getParameterABIAttributes(I, CallerAttrs);
+    AttrBuilder CalleeABIAttrs = getParameterABIAttributes(I, CalleeAttrs);
+    Assert2(CallerABIAttrs == CalleeABIAttrs,
+            "cannot guarantee tail call due to mismatched ABI impacting "
+            "function attributes", &CI, CI.getOperand(I));
+  }
+
+  // - The call must immediately precede a :ref:`ret <i_ret>` instruction,
+  //   or a pointer bitcast followed by a ret instruction.
+  // - The ret instruction must return the (possibly bitcasted) value
+  //   produced by the call or void.
+  Value *RetVal = &CI;
+  Instruction *Next = CI.getNextNode();
+
+  // Handle the optional bitcast.
+  if (BitCastInst *BI = dyn_cast_or_null<BitCastInst>(Next)) {
+    Assert1(BI->getOperand(0) == RetVal,
+            "bitcast following musttail call must use the call", BI);
+    RetVal = BI;
+    Next = BI->getNextNode();
+  }
+
+  // Check the return.
+  ReturnInst *Ret = dyn_cast_or_null<ReturnInst>(Next);
+  Assert1(Ret, "musttail call must be precede a ret with an optional bitcast",
+          &CI);
+  Assert1(!Ret->getReturnValue() || Ret->getReturnValue() == RetVal,
+          "musttail call result must be returned", Ret);
+}
+
 void Verifier::visitCallInst(CallInst &CI) {
   VerifyCallSite(&CI);
 
+  if (CI.isMustTailCall())
+    verifyMustTailCall(CI);
+
   if (Function *F = CI.getCalledFunction())
     if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID())
       visitIntrinsicFunctionCall(ID, CI);
@@ -1731,11 +1833,11 @@ void Verifier::visitLoadInst(LoadInst &LI) {
             "Atomic load must specify explicit alignment", &LI);
     if (!ElTy->isPointerTy()) {
       Assert2(ElTy->isIntegerTy(),
-              "atomic store operand must have integer type!",
+              "atomic load operand must have integer type!",
               &LI, ElTy);
       unsigned Size = ElTy->getPrimitiveSizeInBits();
       Assert2(Size >= 8 && !(Size & (Size - 1)),
-              "atomic store operand must be power-of-two byte-sized integer",
+              "atomic load operand must be power-of-two byte-sized integer",
               &LI, ElTy);
     }
   } else {
@@ -2020,8 +2122,8 @@ void Verifier::visitInstruction(Instruction &I) {
   // instruction, it is an error!
   for (Use &U : I.uses()) {
     if (Instruction *Used = dyn_cast<Instruction>(U.getUser()))
-      Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
-              " embedded in a basic block!", &I, Used);
+      Assert2(Used->getParent() != nullptr, "Instruction referencing"
+              " instruction not embedded in a basic block!", &I, Used);
     else {
       CheckFailed("Use of instruction is not an instruction!", U);
       return;
@@ -2029,7 +2131,7 @@ void Verifier::visitInstruction(Instruction &I) {
   }
 
   for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
-    Assert1(I.getOperand(i) != 0, "Instruction has null operand!", &I);
+    Assert1(I.getOperand(i) != nullptr, "Instruction has null operand!", &I);
 
     // Check to make sure that only first-class-values are operands to
     // instructions.
@@ -2103,11 +2205,6 @@ void Verifier::visitInstruction(Instruction &I) {
   MDNode *MD = I.getMetadata(LLVMContext::MD_range);
   Assert1(!MD || isa<LoadInst>(I), "Ranges are only for loads!", &I);
 
-  if (!DisableDebugInfoVerifier) {
-    MD = I.getMetadata(LLVMContext::MD_dbg);
-    Finder.processLocation(*M, DILocation(MD));
-  }
-
   InstsInThisBlock.insert(&I);
 }
 
@@ -2137,18 +2234,18 @@ bool Verifier::VerifyIntrinsicType(Type *Ty,
   case IITDescriptor::Integer: return !Ty->isIntegerTy(D.Integer_Width);
   case IITDescriptor::Vector: {
     VectorType *VT = dyn_cast<VectorType>(Ty);
-    return VT == 0 || VT->getNumElements() != D.Vector_Width ||
+    return !VT || VT->getNumElements() != D.Vector_Width ||
            VerifyIntrinsicType(VT->getElementType(), Infos, ArgTys);
   }
   case IITDescriptor::Pointer: {
     PointerType *PT = dyn_cast<PointerType>(Ty);
-    return PT == 0 || PT->getAddressSpace() != D.Pointer_AddressSpace ||
+    return !PT || PT->getAddressSpace() != D.Pointer_AddressSpace ||
            VerifyIntrinsicType(PT->getElementType(), Infos, ArgTys);
   }
 
   case IITDescriptor::Struct: {
     StructType *ST = dyn_cast<StructType>(Ty);
-    if (ST == 0 || ST->getNumElements() != D.Struct_NumElements)
+    if (!ST || ST->getNumElements() != D.Struct_NumElements)
       return true;
 
     for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
@@ -2307,17 +2404,7 @@ void Verifier::visitIntrinsicFunctionCall(Intrinsic::ID ID, CallInst &CI) {
     MDNode *MD = cast<MDNode>(CI.getArgOperand(0));
     Assert1(MD->getNumOperands() == 1,
                 "invalid llvm.dbg.declare intrinsic call 2", &CI);
-    if (!DisableDebugInfoVerifier)
-      Finder.processDeclare(*M, cast<DbgDeclareInst>(&CI));
   } break;
-  case Intrinsic::dbg_value: { //llvm.dbg.value
-    if (!DisableDebugInfoVerifier) {
-      Assert1(CI.getArgOperand(0) && isa<MDNode>(CI.getArgOperand(0)),
-              "invalid llvm.dbg.value intrinsic call 1", &CI);
-      Finder.processValue(*M, cast<DbgValueInst>(&CI));
-    }
-    break;
-  }
   case Intrinsic::memcpy:
   case Intrinsic::memmove:
   case Intrinsic::memset:
@@ -2379,25 +2466,58 @@ void Verifier::visitIntrinsicFunctionCall(Intrinsic::ID ID, CallInst &CI) {
   }
 }
 
-void Verifier::verifyDebugInfo() {
+void DebugInfoVerifier::verifyDebugInfo() {
+  if (!VerifyDebugInfo)
+    return;
+
+  DebugInfoFinder Finder;
+  Finder.processModule(*M);
+  processInstructions(Finder);
+
   // Verify Debug Info.
-  if (!DisableDebugInfoVerifier) {
-    for (DICompileUnit CU : Finder.compile_units()) {
-      Assert1(CU.Verify(), "DICompileUnit does not Verify!", CU);
-    }
-    for (DISubprogram S : Finder.subprograms()) {
-      Assert1(S.Verify(), "DISubprogram does not Verify!", S);
-    }
-    for (DIGlobalVariable GV : Finder.global_variables()) {
-      Assert1(GV.Verify(), "DIGlobalVariable does not Verify!", GV);
-    }
-    for (DIType T : Finder.types()) {
-      Assert1(T.Verify(), "DIType does not Verify!", T);
-    }
-    for (DIScope S : Finder.scopes()) {
-      Assert1(S.Verify(), "DIScope does not Verify!", S);
-    }
+  //
+  // NOTE:  The loud braces are necessary for MSVC compatibility.
+  for (DICompileUnit CU : Finder.compile_units()) {
+    Assert1(CU.Verify(), "DICompileUnit does not Verify!", CU);
   }
+  for (DISubprogram S : Finder.subprograms()) {
+    Assert1(S.Verify(), "DISubprogram does not Verify!", S);
+  }
+  for (DIGlobalVariable GV : Finder.global_variables()) {
+    Assert1(GV.Verify(), "DIGlobalVariable does not Verify!", GV);
+  }
+  for (DIType T : Finder.types()) {
+    Assert1(T.Verify(), "DIType does not Verify!", T);
+  }
+  for (DIScope S : Finder.scopes()) {
+    Assert1(S.Verify(), "DIScope does not Verify!", S);
+  }
+}
+
+void DebugInfoVerifier::processInstructions(DebugInfoFinder &Finder) {
+  for (const Function &F : *M)
+    for (auto I = inst_begin(&F), E = inst_end(&F); I != E; ++I) {
+      if (MDNode *MD = I->getMetadata(LLVMContext::MD_dbg))
+        Finder.processLocation(*M, DILocation(MD));
+      if (const CallInst *CI = dyn_cast<CallInst>(&*I))
+        processCallInst(Finder, *CI);
+    }
+}
+
+void DebugInfoVerifier::processCallInst(DebugInfoFinder &Finder,
+                                        const CallInst &CI) {
+  if (Function *F = CI.getCalledFunction())
+    if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID())
+      switch (ID) {
+      case Intrinsic::dbg_declare:
+        Finder.processDeclare(*M, cast<DbgDeclareInst>(&CI));
+        break;
+      case Intrinsic::dbg_value:
+        Finder.processValue(*M, cast<DbgValueInst>(&CI));
+        break;
+      default:
+        break;
+      }
 }
 
 //===----------------------------------------------------------------------===//
@@ -2427,7 +2547,8 @@ bool llvm::verifyModule(const Module &M, raw_ostream *OS) {
 
   // Note that this function's return value is inverted from what you would
   // expect of a function called "verify".
-  return !V.verify(M) || Broken;
+  DebugInfoVerifier DIV(OS ? *OS : NullStr);
+  return !V.verify(M) || !DIV.verify(M) || Broken;
 }
 
 namespace {
@@ -2463,15 +2584,48 @@ struct VerifierLegacyPass : public FunctionPass {
     AU.setPreservesAll();
   }
 };
+struct DebugInfoVerifierLegacyPass : public ModulePass {
+  static char ID;
+
+  DebugInfoVerifier V;
+  bool FatalErrors;
+
+  DebugInfoVerifierLegacyPass() : ModulePass(ID), FatalErrors(true) {
+    initializeDebugInfoVerifierLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+  explicit DebugInfoVerifierLegacyPass(bool FatalErrors)
+      : ModulePass(ID), V(dbgs()), FatalErrors(FatalErrors) {
+    initializeDebugInfoVerifierLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnModule(Module &M) override {
+    if (!V.verify(M) && FatalErrors)
+      report_fatal_error("Broken debug info found, compilation aborted!");
+
+    return false;
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesAll();
+  }
+};
 }
 
 char VerifierLegacyPass::ID = 0;
 INITIALIZE_PASS(VerifierLegacyPass, "verify", "Module Verifier", false, false)
 
+char DebugInfoVerifierLegacyPass::ID = 0;
+INITIALIZE_PASS(DebugInfoVerifierLegacyPass, "verify-di", "Debug Info Verifier",
+                false, false)
+
 FunctionPass *llvm::createVerifierPass(bool FatalErrors) {
   return new VerifierLegacyPass(FatalErrors);
 }
 
+ModulePass *llvm::createDebugInfoVerifierPass(bool FatalErrors) {
+  return new DebugInfoVerifierLegacyPass(FatalErrors);
+}
+
 PreservedAnalyses VerifierPass::run(Module *M) {
   if (verifyModule(*M, &dbgs()) && FatalErrors)
     report_fatal_error("Broken module found, compilation aborted!");
diff --git a/lib/IR/module.modulemap b/lib/IR/module.modulemap
new file mode 100644
index 0000000..9698e91
--- /dev/null
+++ b/lib/IR/module.modulemap
@@ -0,0 +1 @@
+module IR { requires cplusplus umbrella "." module * { export * } }