X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FBitcode%2FReader%2FBitcodeReader.cpp;h=4265bf7edf1610afae034e58e1c25ee5b02c1c4f;hp=cafdd12529af171b2c296f20cab0949bf50b4ad1;hb=e39dba9f078041e4bca7e821dfb252c1cc4a3fee;hpb=a20bcb9969aa4f0d989e8f039d6af3a43357d310

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index cafdd12529a..4265bf7edf1 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -25,27 +25,53 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ManagedStatic.h"
+
 using namespace llvm;
-using std::error_code;
 
 enum {
   SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
 };
 
-void BitcodeReader::materializeForwardReferencedFunctions() {
-  while (!BlockAddrFwdRefs.empty()) {
-    Function *F = BlockAddrFwdRefs.begin()->first;
-    F->Materialize();
+std::error_code BitcodeReader::materializeForwardReferencedFunctions() {
+  if (WillMaterializeAllForwardRefs)
+    return std::error_code();
+
+  // Prevent recursion.
+  WillMaterializeAllForwardRefs = true;
+
+  while (!BasicBlockFwdRefQueue.empty()) {
+    Function *F = BasicBlockFwdRefQueue.front();
+    BasicBlockFwdRefQueue.pop_front();
+    assert(F && "Expected valid function");
+    if (!BasicBlockFwdRefs.count(F))
+      // Already materialized.
+      continue;
+
+    // Check for a function that isn't materializable to prevent an infinite
+    // loop.  When parsing a blockaddress stored in a global variable, there
+    // isn't a trivial way to check if a function will have a body without a
+    // linear search through FunctionsWithBodies, so just check it here.
+    if (!F->isMaterializable())
+      return Error(BitcodeError::NeverResolvedFunctionFromBlockAddress);
+
+    // Try to materialize F.
+    if (std::error_code EC = materialize(F))
+      return EC;
   }
+  assert(BasicBlockFwdRefs.empty() && "Function missing from queue");
+
+  // Reset state.
+  WillMaterializeAllForwardRefs = false;
+  return std::error_code();
 }
 
 void BitcodeReader::FreeState() {
-  if (BufferOwned)
-    delete Buffer;
   Buffer = nullptr;
   std::vector<Type*>().swap(TypeList);
   ValueList.clear();
   MDValueList.clear();
+  std::vector<Comdat *>().swap(ComdatList);
 
   std::vector<AttributeSet>().swap(MAttributes);
   std::vector<BasicBlock*>().swap(FunctionBBs);
@@ -53,7 +79,8 @@ void BitcodeReader::FreeState() {
   DeferredFunctionInfo.clear();
   MDKindMap.clear();
 
-  assert(BlockAddrFwdRefs.empty() && "Unresolved blockaddress fwd references");
+  assert(BasicBlockFwdRefs.empty() && "Unresolved blockaddress fwd references");
+  BasicBlockFwdRefQueue.clear();
 }
 
 //===----------------------------------------------------------------------===//
@@ -206,6 +233,22 @@ static SynchronizationScope GetDecodedSynchScope(unsigned Val) {
   }
 }
 
+static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
+  switch (Val) {
+  default: // Map unknown selection kinds to any.
+  case bitc::COMDAT_SELECTION_KIND_ANY:
+    return Comdat::Any;
+  case bitc::COMDAT_SELECTION_KIND_EXACT_MATCH:
+    return Comdat::ExactMatch;
+  case bitc::COMDAT_SELECTION_KIND_LARGEST:
+    return Comdat::Largest;
+  case bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES:
+    return Comdat::NoDuplicates;
+  case bitc::COMDAT_SELECTION_KIND_SAME_SIZE:
+    return Comdat::SameSize;
+  }
+}
+
 static void UpgradeDLLImportExportLinkage(llvm::GlobalValue *GV, unsigned Val) {
   switch (Val) {
   case 5: GV->setDLLStorageClass(GlobalValue::DLLImportStorageClass); break;
@@ -237,7 +280,7 @@ namespace {
 
 
     /// Provide fast operand accessors
-    //DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+    DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
   };
 }
 
@@ -246,6 +289,7 @@ template <>
 struct OperandTraits<ConstantPlaceHolder> :
   public FixedNumOperandTraits<ConstantPlaceHolder, 1> {
 };
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantPlaceHolder, Value)
 }
 
 
@@ -394,43 +438,58 @@ void BitcodeReaderValueList::ResolveConstantForwardRefs() {
   }
 }
 
-void BitcodeReaderMDValueList::AssignValue(Value *V, unsigned Idx) {
+void BitcodeReaderMDValueList::AssignValue(Metadata *MD, unsigned Idx) {
   if (Idx == size()) {
-    push_back(V);
+    push_back(MD);
     return;
   }
 
   if (Idx >= size())
     resize(Idx+1);
 
-  WeakVH &OldV = MDValuePtrs[Idx];
-  if (!OldV) {
-    OldV = V;
+  TrackingMDRef &OldMD = MDValuePtrs[Idx];
+  if (!OldMD) {
+    OldMD.reset(MD);
     return;
   }
 
   // If there was a forward reference to this value, replace it.
-  MDNode *PrevVal = cast<MDNode>(OldV);
-  OldV->replaceAllUsesWith(V);
-  MDNode::deleteTemporary(PrevVal);
-  // Deleting PrevVal sets Idx value in MDValuePtrs to null. Set new
-  // value for Idx.
-  MDValuePtrs[Idx] = V;
+  MDNodeFwdDecl *PrevMD = cast<MDNodeFwdDecl>(OldMD.get());
+  PrevMD->replaceAllUsesWith(MD);
+  MDNode::deleteTemporary(PrevMD);
+  --NumFwdRefs;
 }
 
-Value *BitcodeReaderMDValueList::getValueFwdRef(unsigned Idx) {
+Metadata *BitcodeReaderMDValueList::getValueFwdRef(unsigned Idx) {
   if (Idx >= size())
     resize(Idx + 1);
 
-  if (Value *V = MDValuePtrs[Idx]) {
-    assert(V->getType()->isMetadataTy() && "Type mismatch in value table!");
-    return V;
-  }
+  if (Metadata *MD = MDValuePtrs[Idx])
+    return MD;
 
   // Create and return a placeholder, which will later be RAUW'd.
-  Value *V = MDNode::getTemporary(Context, None);
-  MDValuePtrs[Idx] = V;
-  return V;
+  AnyFwdRefs = true;
+  ++NumFwdRefs;
+  Metadata *MD = MDNode::getTemporary(Context, None);
+  MDValuePtrs[Idx].reset(MD);
+  return MD;
+}
+
+void BitcodeReaderMDValueList::tryToResolveCycles() {
+  if (!AnyFwdRefs)
+    // Nothing to do.
+    return;
+
+  if (NumFwdRefs)
+    // Still forward references... can't resolve cycles.
+    return;
+
+  // Resolve any cycles.
+  for (auto &MD : MDValuePtrs) {
+    assert(!(MD && isa<MDNodeFwdDecl>(MD)) && "Unexpected forward reference");
+    if (auto *G = dyn_cast_or_null<GenericMDNode>(MD))
+      G->resolveCycles();
+  }
 }
 
 Type *BitcodeReader::getTypeByID(unsigned ID) {
@@ -443,7 +502,20 @@ Type *BitcodeReader::getTypeByID(unsigned ID) {
 
   // If we have a forward reference, the only possible case is when it is to a
   // named struct.  Just create a placeholder for now.
-  return TypeList[ID] = StructType::create(Context);
+  return TypeList[ID] = createIdentifiedStructType(Context);
+}
+
+StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context,
+                                                      StringRef Name) {
+  auto *Ret = StructType::create(Context, Name);
+  IdentifiedStructTypes.push_back(Ret);
+  return Ret;
+}
+
+StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context) {
+  auto *Ret = StructType::create(Context);
+  IdentifiedStructTypes.push_back(Ret);
+  return Ret;
 }
 
 
@@ -471,12 +543,12 @@ static void decodeLLVMAttributesForBitcode(AttrBuilder &B,
                 (EncodedAttrs & 0xffff));
 }
 
-error_code BitcodeReader::ParseAttributeBlock() {
+std::error_code BitcodeReader::ParseAttributeBlock() {
   if (Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   if (!MAttributes.empty())
-    return Error(InvalidMultipleBlocks);
+    return Error(BitcodeError::InvalidMultipleBlocks);
 
   SmallVector<uint64_t, 64> Record;
 
@@ -489,9 +561,9 @@ error_code BitcodeReader::ParseAttributeBlock() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -505,7 +577,7 @@ error_code BitcodeReader::ParseAttributeBlock() {
     case bitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...]
       // FIXME: Remove in 4.0.
       if (Record.size() & 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
         AttrBuilder B;
@@ -574,6 +646,8 @@ static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
     return Attribute::NonLazyBind;
   case bitc::ATTR_KIND_NON_NULL:
     return Attribute::NonNull;
+  case bitc::ATTR_KIND_DEREFERENCEABLE:
+    return Attribute::Dereferenceable;
   case bitc::ATTR_KIND_NO_RED_ZONE:
     return Attribute::NoRedZone;
   case bitc::ATTR_KIND_NO_RETURN:
@@ -617,20 +691,20 @@ static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
   }
 }
 
-error_code BitcodeReader::ParseAttrKind(uint64_t Code,
-                                        Attribute::AttrKind *Kind) {
+std::error_code BitcodeReader::ParseAttrKind(uint64_t Code,
+                                             Attribute::AttrKind *Kind) {
   *Kind = GetAttrFromCode(Code);
   if (*Kind == Attribute::None)
-    return Error(InvalidValue);
-  return error_code();
+    return Error(BitcodeError::InvalidValue);
+  return std::error_code();
 }
 
-error_code BitcodeReader::ParseAttributeGroupBlock() {
+std::error_code BitcodeReader::ParseAttributeGroupBlock() {
   if (Stream.EnterSubBlock(bitc::PARAMATTR_GROUP_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   if (!MAttributeGroups.empty())
-    return Error(InvalidMultipleBlocks);
+    return Error(BitcodeError::InvalidMultipleBlocks);
 
   SmallVector<uint64_t, 64> Record;
 
@@ -641,9 +715,9 @@ error_code BitcodeReader::ParseAttributeGroupBlock() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -656,7 +730,7 @@ error_code BitcodeReader::ParseAttributeGroupBlock() {
       break;
     case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       uint64_t GrpID = Record[0];
       uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
@@ -665,18 +739,20 @@ error_code BitcodeReader::ParseAttributeGroupBlock() {
       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
         if (Record[i] == 0) {        // Enum attribute
           Attribute::AttrKind Kind;
-          if (error_code EC = ParseAttrKind(Record[++i], &Kind))
+          if (std::error_code EC = ParseAttrKind(Record[++i], &Kind))
             return EC;
 
           B.addAttribute(Kind);
-        } else if (Record[i] == 1) { // Align attribute
+        } else if (Record[i] == 1) { // Integer attribute
           Attribute::AttrKind Kind;
-          if (error_code EC = ParseAttrKind(Record[++i], &Kind))
+          if (std::error_code EC = ParseAttrKind(Record[++i], &Kind))
             return EC;
           if (Kind == Attribute::Alignment)
             B.addAlignmentAttr(Record[++i]);
-          else
+          else if (Kind == Attribute::StackAlignment)
             B.addStackAlignmentAttr(Record[++i]);
+          else if (Kind == Attribute::Dereferenceable)
+            B.addDereferenceableAttr(Record[++i]);
         } else {                     // String attribute
           assert((Record[i] == 3 || Record[i] == 4) &&
                  "Invalid attribute group entry");
@@ -707,16 +783,16 @@ error_code BitcodeReader::ParseAttributeGroupBlock() {
   }
 }
 
-error_code BitcodeReader::ParseTypeTable() {
+std::error_code BitcodeReader::ParseTypeTable() {
   if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   return ParseTypeTableBody();
 }
 
-error_code BitcodeReader::ParseTypeTableBody() {
+std::error_code BitcodeReader::ParseTypeTableBody() {
   if (!TypeList.empty())
-    return Error(InvalidMultipleBlocks);
+    return Error(BitcodeError::InvalidMultipleBlocks);
 
   SmallVector<uint64_t, 64> Record;
   unsigned NumRecords = 0;
@@ -730,11 +806,11 @@ error_code BitcodeReader::ParseTypeTableBody() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
       if (NumRecords != TypeList.size())
-        return Error(MalformedBlock);
-      return error_code();
+        return Error(BitcodeError::MalformedBlock);
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -745,12 +821,12 @@ error_code BitcodeReader::ParseTypeTableBody() {
     Type *ResultTy = nullptr;
     switch (Stream.readRecord(Entry.ID, Record)) {
     default:
-      return Error(InvalidValue);
+      return Error(BitcodeError::InvalidValue);
     case bitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
       // TYPE_CODE_NUMENTRY contains a count of the number of types in the
       // type list.  This allows us to reserve space.
       if (Record.size() < 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       TypeList.resize(Record[0]);
       continue;
     case bitc::TYPE_CODE_VOID:      // VOID
@@ -785,20 +861,20 @@ error_code BitcodeReader::ParseTypeTableBody() {
       break;
     case bitc::TYPE_CODE_INTEGER:   // INTEGER: [width]
       if (Record.size() < 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       ResultTy = IntegerType::get(Context, Record[0]);
       break;
     case bitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
                                     //          [pointee type, address space]
       if (Record.size() < 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       unsigned AddressSpace = 0;
       if (Record.size() == 2)
         AddressSpace = Record[1];
       ResultTy = getTypeByID(Record[0]);
       if (!ResultTy)
-        return Error(InvalidType);
+        return Error(BitcodeError::InvalidType);
       ResultTy = PointerType::get(ResultTy, AddressSpace);
       break;
     }
@@ -806,7 +882,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
       // FIXME: attrid is dead, remove it in LLVM 4.0
       // FUNCTION: [vararg, attrid, retty, paramty x N]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SmallVector<Type*, 8> ArgTys;
       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
@@ -817,7 +893,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
 
       ResultTy = getTypeByID(Record[2]);
       if (!ResultTy || ArgTys.size() < Record.size()-3)
-        return Error(InvalidType);
+        return Error(BitcodeError::InvalidType);
 
       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
       break;
@@ -825,7 +901,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
     case bitc::TYPE_CODE_FUNCTION: {
       // FUNCTION: [vararg, retty, paramty x N]
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SmallVector<Type*, 8> ArgTys;
       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
@@ -836,14 +912,14 @@ error_code BitcodeReader::ParseTypeTableBody() {
 
       ResultTy = getTypeByID(Record[1]);
       if (!ResultTy || ArgTys.size() < Record.size()-2)
-        return Error(InvalidType);
+        return Error(BitcodeError::InvalidType);
 
       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
       break;
     }
     case bitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
       if (Record.size() < 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SmallVector<Type*, 8> EltTys;
       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
@@ -852,21 +928,21 @@ error_code BitcodeReader::ParseTypeTableBody() {
           break;
       }
       if (EltTys.size() != Record.size()-1)
-        return Error(InvalidType);
+        return Error(BitcodeError::InvalidType);
       ResultTy = StructType::get(Context, EltTys, Record[0]);
       break;
     }
     case bitc::TYPE_CODE_STRUCT_NAME:   // STRUCT_NAME: [strchr x N]
       if (ConvertToString(Record, 0, TypeName))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       continue;
 
     case bitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
       if (Record.size() < 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       if (NumRecords >= TypeList.size())
-        return Error(InvalidTYPETable);
+        return Error(BitcodeError::InvalidTYPETable);
 
       // Check to see if this was forward referenced, if so fill in the temp.
       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
@@ -874,7 +950,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
         Res->setName(TypeName);
         TypeList[NumRecords] = nullptr;
       } else  // Otherwise, create a new struct.
-        Res = StructType::create(Context, TypeName);
+        Res = createIdentifiedStructType(Context, TypeName);
       TypeName.clear();
 
       SmallVector<Type*, 8> EltTys;
@@ -885,17 +961,17 @@ error_code BitcodeReader::ParseTypeTableBody() {
           break;
       }
       if (EltTys.size() != Record.size()-1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Res->setBody(EltTys, Record[0]);
       ResultTy = Res;
       break;
     }
     case bitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
       if (Record.size() != 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       if (NumRecords >= TypeList.size())
-        return Error(InvalidTYPETable);
+        return Error(BitcodeError::InvalidTYPETable);
 
       // Check to see if this was forward referenced, if so fill in the temp.
       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
@@ -903,40 +979,40 @@ error_code BitcodeReader::ParseTypeTableBody() {
         Res->setName(TypeName);
         TypeList[NumRecords] = nullptr;
       } else  // Otherwise, create a new struct with no body.
-        Res = StructType::create(Context, TypeName);
+        Res = createIdentifiedStructType(Context, TypeName);
       TypeName.clear();
       ResultTy = Res;
       break;
     }
     case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if ((ResultTy = getTypeByID(Record[1])))
         ResultTy = ArrayType::get(ResultTy, Record[0]);
       else
-        return Error(InvalidType);
+        return Error(BitcodeError::InvalidType);
       break;
     case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if ((ResultTy = getTypeByID(Record[1])))
         ResultTy = VectorType::get(ResultTy, Record[0]);
       else
-        return Error(InvalidType);
+        return Error(BitcodeError::InvalidType);
       break;
     }
 
     if (NumRecords >= TypeList.size())
-      return Error(InvalidTYPETable);
+      return Error(BitcodeError::InvalidTYPETable);
     assert(ResultTy && "Didn't read a type?");
     assert(!TypeList[NumRecords] && "Already read type?");
     TypeList[NumRecords++] = ResultTy;
   }
 }
 
-error_code BitcodeReader::ParseValueSymbolTable() {
+std::error_code BitcodeReader::ParseValueSymbolTable() {
   if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   SmallVector<uint64_t, 64> Record;
 
@@ -948,9 +1024,9 @@ error_code BitcodeReader::ParseValueSymbolTable() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -963,10 +1039,10 @@ error_code BitcodeReader::ParseValueSymbolTable() {
       break;
     case bitc::VST_CODE_ENTRY: {  // VST_ENTRY: [valueid, namechar x N]
       if (ConvertToString(Record, 1, ValueName))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       unsigned ValueID = Record[0];
       if (ValueID >= ValueList.size() || !ValueList[ValueID])
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Value *V = ValueList[ValueID];
 
       V->setName(StringRef(ValueName.data(), ValueName.size()));
@@ -975,10 +1051,10 @@ error_code BitcodeReader::ParseValueSymbolTable() {
     }
     case bitc::VST_CODE_BBENTRY: {
       if (ConvertToString(Record, 1, ValueName))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       BasicBlock *BB = getBasicBlock(Record[0]);
       if (!BB)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       BB->setName(StringRef(ValueName.data(), ValueName.size()));
       ValueName.clear();
@@ -988,11 +1064,11 @@ error_code BitcodeReader::ParseValueSymbolTable() {
   }
 }
 
-error_code BitcodeReader::ParseMetadata() {
+std::error_code BitcodeReader::ParseMetadata() {
   unsigned NextMDValueNo = MDValueList.size();
 
   if (Stream.EnterSubBlock(bitc::METADATA_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   SmallVector<uint64_t, 64> Record;
 
@@ -1003,15 +1079,15 @@ error_code BitcodeReader::ParseMetadata() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      MDValueList.tryToResolveCycles();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
     }
 
-    bool IsFunctionLocal = false;
     // Read a record.
     Record.clear();
     unsigned Code = Stream.readRecord(Entry.ID, Record);
@@ -1034,52 +1110,100 @@ error_code BitcodeReader::ParseMetadata() {
       for (unsigned i = 0; i != Size; ++i) {
         MDNode *MD = dyn_cast_or_null<MDNode>(MDValueList.getValueFwdRef(Record[i]));
         if (!MD)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         NMD->addOperand(MD);
       }
       break;
     }
-    case bitc::METADATA_FN_NODE:
-      IsFunctionLocal = true;
-      // fall-through
-    case bitc::METADATA_NODE: {
+    case bitc::METADATA_OLD_FN_NODE: {
+      // This is a LocalAsMetadata record, the only type of function-local
+      // metadata.
       if (Record.size() % 2 == 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
+
+      // If this isn't a LocalAsMetadata record, we're dropping it.  This used
+      // to be legal, but there's no upgrade path.
+      auto dropRecord = [&] {
+        MDValueList.AssignValue(MDNode::get(Context, None), NextMDValueNo++);
+      };
+      if (Record.size() != 2) {
+        dropRecord();
+        break;
+      }
+
+      Type *Ty = getTypeByID(Record[0]);
+      if (Ty->isMetadataTy() || Ty->isVoidTy()) {
+        dropRecord();
+        break;
+      }
+
+      MDValueList.AssignValue(
+          LocalAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
+          NextMDValueNo++);
+      break;
+    }
+    case bitc::METADATA_OLD_NODE: {
+      if (Record.size() % 2 == 1)
+        return Error(BitcodeError::InvalidRecord);
 
       unsigned Size = Record.size();
-      SmallVector<Value*, 8> Elts;
+      SmallVector<Metadata *, 8> Elts;
       for (unsigned i = 0; i != Size; i += 2) {
         Type *Ty = getTypeByID(Record[i]);
         if (!Ty)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         if (Ty->isMetadataTy())
           Elts.push_back(MDValueList.getValueFwdRef(Record[i+1]));
-        else if (!Ty->isVoidTy())
-          Elts.push_back(ValueList.getValueFwdRef(Record[i+1], Ty));
-        else
+        else if (!Ty->isVoidTy()) {
+          auto *MD =
+              ValueAsMetadata::get(ValueList.getValueFwdRef(Record[i + 1], Ty));
+          assert(isa<ConstantAsMetadata>(MD) &&
+                 "Expected non-function-local metadata");
+          Elts.push_back(MD);
+        } else
           Elts.push_back(nullptr);
       }
-      Value *V = MDNode::getWhenValsUnresolved(Context, Elts, IsFunctionLocal);
-      IsFunctionLocal = false;
-      MDValueList.AssignValue(V, NextMDValueNo++);
+      MDValueList.AssignValue(MDNode::get(Context, Elts), NextMDValueNo++);
+      break;
+    }
+    case bitc::METADATA_VALUE: {
+      if (Record.size() != 2)
+        return Error(BitcodeError::InvalidRecord);
+
+      Type *Ty = getTypeByID(Record[0]);
+      if (Ty->isMetadataTy() || Ty->isVoidTy())
+        return Error(BitcodeError::InvalidRecord);
+
+      MDValueList.AssignValue(
+          ValueAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
+          NextMDValueNo++);
+      break;
+    }
+    case bitc::METADATA_NODE: {
+      SmallVector<Metadata *, 8> Elts;
+      Elts.reserve(Record.size());
+      for (unsigned ID : Record)
+        Elts.push_back(ID ? MDValueList.getValueFwdRef(ID - 1) : nullptr);
+      MDValueList.AssignValue(MDNode::get(Context, Elts), NextMDValueNo++);
       break;
     }
     case bitc::METADATA_STRING: {
-      SmallString<8> String(Record.begin(), Record.end());
-      Value *V = MDString::get(Context, String);
-      MDValueList.AssignValue(V, NextMDValueNo++);
+      std::string String(Record.begin(), Record.end());
+      llvm::UpgradeMDStringConstant(String);
+      Metadata *MD = MDString::get(Context, String);
+      MDValueList.AssignValue(MD, NextMDValueNo++);
       break;
     }
     case bitc::METADATA_KIND: {
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       unsigned Kind = Record[0];
       SmallString<8> Name(Record.begin()+1, Record.end());
 
       unsigned NewKind = TheModule->getMDKindID(Name.str());
       if (!MDKindMap.insert(std::make_pair(Kind, NewKind)).second)
-        return Error(ConflictingMETADATA_KINDRecords);
+        return Error(BitcodeError::ConflictingMETADATA_KINDRecords);
       break;
     }
     }
@@ -1099,14 +1223,16 @@ uint64_t BitcodeReader::decodeSignRotatedValue(uint64_t V) {
 
 /// ResolveGlobalAndAliasInits - Resolve all of the initializers for global
 /// values and aliases that we can.
-error_code BitcodeReader::ResolveGlobalAndAliasInits() {
+std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
   std::vector<std::pair<Function*, unsigned> > FunctionPrefixWorklist;
+  std::vector<std::pair<Function*, unsigned> > FunctionPrologueWorklist;
 
   GlobalInitWorklist.swap(GlobalInits);
   AliasInitWorklist.swap(AliasInits);
   FunctionPrefixWorklist.swap(FunctionPrefixes);
+  FunctionPrologueWorklist.swap(FunctionPrologues);
 
   while (!GlobalInitWorklist.empty()) {
     unsigned ValID = GlobalInitWorklist.back().second;
@@ -1117,7 +1243,7 @@ error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         GlobalInitWorklist.back().first->setInitializer(C);
       else
-        return Error(ExpectedConstant);
+        return Error(BitcodeError::ExpectedConstant);
     }
     GlobalInitWorklist.pop_back();
   }
@@ -1130,7 +1256,7 @@ error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         AliasInitWorklist.back().first->setAliasee(C);
       else
-        return Error(ExpectedConstant);
+        return Error(BitcodeError::ExpectedConstant);
     }
     AliasInitWorklist.pop_back();
   }
@@ -1143,12 +1269,25 @@ error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         FunctionPrefixWorklist.back().first->setPrefixData(C);
       else
-        return Error(ExpectedConstant);
+        return Error(BitcodeError::ExpectedConstant);
     }
     FunctionPrefixWorklist.pop_back();
   }
 
-  return error_code();
+  while (!FunctionPrologueWorklist.empty()) {
+    unsigned ValID = FunctionPrologueWorklist.back().second;
+    if (ValID >= ValueList.size()) {
+      FunctionPrologues.push_back(FunctionPrologueWorklist.back());
+    } else {
+      if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
+        FunctionPrologueWorklist.back().first->setPrologueData(C);
+      else
+        return Error(BitcodeError::ExpectedConstant);
+    }
+    FunctionPrologueWorklist.pop_back();
+  }
+
+  return std::error_code();
 }
 
 static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
@@ -1159,9 +1298,9 @@ static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
   return APInt(TypeBits, Words);
 }
 
-error_code BitcodeReader::ParseConstants() {
+std::error_code BitcodeReader::ParseConstants() {
   if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   SmallVector<uint64_t, 64> Record;
 
@@ -1174,15 +1313,15 @@ error_code BitcodeReader::ParseConstants() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
       if (NextCstNo != ValueList.size())
-        return Error(InvalidConstantReference);
+        return Error(BitcodeError::InvalidConstantReference);
 
       // Once all the constants have been read, go through and resolve forward
       // references.
       ValueList.ResolveConstantForwardRefs();
-      return error_code();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -1199,9 +1338,9 @@ error_code BitcodeReader::ParseConstants() {
       break;
     case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
       if (Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if (Record[0] >= TypeList.size() || !TypeList[Record[0]])
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       CurTy = TypeList[Record[0]];
       continue;  // Skip the ValueList manipulation.
     case bitc::CST_CODE_NULL:      // NULL
@@ -1209,12 +1348,12 @@ error_code BitcodeReader::ParseConstants() {
       break;
     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
       if (!CurTy->isIntegerTy() || Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
       break;
     case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
       if (!CurTy->isIntegerTy() || Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       APInt VInt = ReadWideAPInt(Record,
                                  cast<IntegerType>(CurTy)->getBitWidth());
@@ -1224,7 +1363,7 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
       if (Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if (CurTy->isHalfTy())
         V = ConstantFP::get(Context, APFloat(APFloat::IEEEhalf,
                                              APInt(16, (uint16_t)Record[0])));
@@ -1254,7 +1393,7 @@ error_code BitcodeReader::ParseConstants() {
 
     case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
       if (Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       unsigned Size = Record.size();
       SmallVector<Constant*, 16> Elts;
@@ -1282,7 +1421,7 @@ error_code BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_STRING:    // STRING: [values]
     case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
       if (Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       SmallString<16> Elts(Record.begin(), Record.end());
       V = ConstantDataArray::getString(Context, Elts,
@@ -1291,7 +1430,7 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_DATA: {// DATA: [n x value]
       if (Record.empty())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
       unsigned Size = Record.size();
@@ -1336,14 +1475,14 @@ error_code BitcodeReader::ParseConstants() {
         else
           V = ConstantDataArray::get(Context, Elts);
       } else {
-        return Error(InvalidTypeForValue);
+        return Error(BitcodeError::InvalidTypeForValue);
       }
       break;
     }
 
     case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
       if (Opc < 0) {
         V = UndefValue::get(CurTy);  // Unknown binop.
@@ -1374,14 +1513,14 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       int Opc = GetDecodedCastOpcode(Record[0]);
       if (Opc < 0) {
         V = UndefValue::get(CurTy);  // Unknown cast.
       } else {
         Type *OpTy = getTypeByID(Record[1]);
         if (!OpTy)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
         V = UpgradeBitCastExpr(Opc, Op, CurTy);
         if (!V) V = ConstantExpr::getCast(Opc, Op, CurTy);
@@ -1391,12 +1530,12 @@ error_code BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_CE_INBOUNDS_GEP:
     case bitc::CST_CODE_CE_GEP: {  // CE_GEP:        [n x operands]
       if (Record.size() & 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SmallVector<Constant*, 16> Elts;
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
         Type *ElTy = getTypeByID(Record[i]);
         if (!ElTy)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
       }
       ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
@@ -1407,7 +1546,7 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_SELECT: {  // CE_SELECT: [opval#, opval#, opval#]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       Type *SelectorTy = Type::getInt1Ty(Context);
 
@@ -1426,22 +1565,22 @@ error_code BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_CE_EXTRACTELT
         : { // CE_EXTRACTELT: [opty, opval, opty, opval]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       VectorType *OpTy =
         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
       if (!OpTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = nullptr;
       if (Record.size() == 4) {
         Type *IdxTy = getTypeByID(Record[2]);
         if (!IdxTy)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         Op1 = ValueList.getConstantFwdRef(Record[3], IdxTy);
       } else // TODO: Remove with llvm 4.0
         Op1 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
       if (!Op1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       V = ConstantExpr::getExtractElement(Op0, Op1);
       break;
     }
@@ -1449,7 +1588,7 @@ error_code BitcodeReader::ParseConstants() {
         : { // CE_INSERTELT: [opval, opval, opty, opval]
       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
       if (Record.size() < 3 || !OpTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
                                                   OpTy->getElementType());
@@ -1457,19 +1596,19 @@ error_code BitcodeReader::ParseConstants() {
       if (Record.size() == 4) {
         Type *IdxTy = getTypeByID(Record[2]);
         if (!IdxTy)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         Op2 = ValueList.getConstantFwdRef(Record[3], IdxTy);
       } else // TODO: Remove with llvm 4.0
         Op2 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
       if (!Op2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       V = ConstantExpr::getInsertElement(Op0, Op1, Op2);
       break;
     }
     case bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
       if (Record.size() < 3 || !OpTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
@@ -1483,7 +1622,7 @@ error_code BitcodeReader::ParseConstants() {
       VectorType *OpTy =
         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
       if (Record.size() < 4 || !RTy || !OpTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
@@ -1494,10 +1633,10 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
       if (Record.size() < 4)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *OpTy = getTypeByID(Record[0]);
       if (!OpTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
 
@@ -1511,16 +1650,16 @@ error_code BitcodeReader::ParseConstants() {
     // FIXME: Remove with the 4.0 release.
     case bitc::CST_CODE_INLINEASM_OLD: {
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       std::string AsmStr, ConstrStr;
       bool HasSideEffects = Record[0] & 1;
       bool IsAlignStack = Record[0] >> 1;
       unsigned AsmStrSize = Record[1];
       if (2+AsmStrSize >= Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       unsigned ConstStrSize = Record[2+AsmStrSize];
       if (3+AsmStrSize+ConstStrSize > Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       for (unsigned i = 0; i != AsmStrSize; ++i)
         AsmStr += (char)Record[2+i];
@@ -1535,17 +1674,17 @@ error_code BitcodeReader::ParseConstants() {
     // inteldialect).
     case bitc::CST_CODE_INLINEASM: {
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       std::string AsmStr, ConstrStr;
       bool HasSideEffects = Record[0] & 1;
       bool IsAlignStack = (Record[0] >> 1) & 1;
       unsigned AsmDialect = Record[0] >> 2;
       unsigned AsmStrSize = Record[1];
       if (2+AsmStrSize >= Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       unsigned ConstStrSize = Record[2+AsmStrSize];
       if (3+AsmStrSize+ConstStrSize > Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       for (unsigned i = 0; i != AsmStrSize; ++i)
         AsmStr += (char)Record[2+i];
@@ -1559,35 +1698,46 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_BLOCKADDRESS:{
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *FnTy = getTypeByID(Record[0]);
       if (!FnTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Function *Fn =
         dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
       if (!Fn)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
+
+      // Don't let Fn get dematerialized.
+      BlockAddressesTaken.insert(Fn);
 
       // If the function is already parsed we can insert the block address right
       // away.
+      BasicBlock *BB;
+      unsigned BBID = Record[2];
+      if (!BBID)
+        // Invalid reference to entry block.
+        return Error(BitcodeError::InvalidID);
       if (!Fn->empty()) {
         Function::iterator BBI = Fn->begin(), BBE = Fn->end();
-        for (size_t I = 0, E = Record[2]; I != E; ++I) {
+        for (size_t I = 0, E = BBID; I != E; ++I) {
           if (BBI == BBE)
-            return Error(InvalidID);
+            return Error(BitcodeError::InvalidID);
           ++BBI;
         }
-        V = BlockAddress::get(Fn, BBI);
+        BB = BBI;
       } else {
         // Otherwise insert a placeholder and remember it so it can be inserted
         // when the function is parsed.
-        GlobalVariable *FwdRef = new GlobalVariable(*Fn->getParent(),
-                                                    Type::getInt8Ty(Context),
-                                            false, GlobalValue::InternalLinkage,
-                                                    nullptr, "");
-        BlockAddrFwdRefs[Fn].push_back(std::make_pair(Record[2], FwdRef));
-        V = FwdRef;
+        auto &FwdBBs = BasicBlockFwdRefs[Fn];
+        if (FwdBBs.empty())
+          BasicBlockFwdRefQueue.push_back(Fn);
+        if (FwdBBs.size() < BBID + 1)
+          FwdBBs.resize(BBID + 1);
+        if (!FwdBBs[BBID])
+          FwdBBs[BBID] = BasicBlock::Create(Context);
+        BB = FwdBBs[BBID];
       }
+      V = BlockAddress::get(Fn, BB);
       break;
     }
     }
@@ -1597,22 +1747,21 @@ error_code BitcodeReader::ParseConstants() {
   }
 }
 
-error_code BitcodeReader::ParseUseLists() {
+std::error_code BitcodeReader::ParseUseLists() {
   if (Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
-    return Error(InvalidRecord);
-
-  SmallVector<uint64_t, 64> Record;
+    return Error(BitcodeError::InvalidRecord);
 
   // Read all the records.
+  SmallVector<uint64_t, 64> Record;
   while (1) {
     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
 
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -1620,14 +1769,42 @@ error_code BitcodeReader::ParseUseLists() {
 
     // Read a use list record.
     Record.clear();
+    bool IsBB = false;
     switch (Stream.readRecord(Entry.ID, Record)) {
     default:  // Default behavior: unknown type.
       break;
-    case bitc::USELIST_CODE_ENTRY: { // USELIST_CODE_ENTRY: TBD.
+    case bitc::USELIST_CODE_BB:
+      IsBB = true;
+      // fallthrough
+    case bitc::USELIST_CODE_DEFAULT: {
       unsigned RecordLength = Record.size();
-      if (RecordLength < 1)
-        return Error(InvalidRecord);
-      UseListRecords.push_back(Record);
+      if (RecordLength < 3)
+        // Records should have at least an ID and two indexes.
+        return Error(BitcodeError::InvalidRecord);
+      unsigned ID = Record.back();
+      Record.pop_back();
+
+      Value *V;
+      if (IsBB) {
+        assert(ID < FunctionBBs.size() && "Basic block not found");
+        V = FunctionBBs[ID];
+      } else
+        V = ValueList[ID];
+      unsigned NumUses = 0;
+      SmallDenseMap<const Use *, unsigned, 16> Order;
+      for (const Use &U : V->uses()) {
+        if (++NumUses > Record.size())
+          break;
+        Order[&U] = Record[NumUses - 1];
+      }
+      if (Order.size() != Record.size() || NumUses > Record.size())
+        // Mismatches can happen if the functions are being materialized lazily
+        // (out-of-order), or a value has been upgraded.
+        break;
+
+      V->sortUseList([&](const Use &L, const Use &R) {
+        return Order.lookup(&L) < Order.lookup(&R);
+      });
       break;
     }
     }
@@ -1637,10 +1814,10 @@ error_code BitcodeReader::ParseUseLists() {
 /// RememberAndSkipFunctionBody - When we see the block for a function body,
 /// remember where it is and then skip it.  This lets us lazily deserialize the
 /// functions.
-error_code BitcodeReader::RememberAndSkipFunctionBody() {
+std::error_code BitcodeReader::RememberAndSkipFunctionBody() {
   // Get the function we are talking about.
   if (FunctionsWithBodies.empty())
-    return Error(InsufficientFunctionProtos);
+    return Error(BitcodeError::InsufficientFunctionProtos);
 
   Function *Fn = FunctionsWithBodies.back();
   FunctionsWithBodies.pop_back();
@@ -1651,15 +1828,15 @@ error_code BitcodeReader::RememberAndSkipFunctionBody() {
 
   // Skip over the function block for now.
   if (Stream.SkipBlock())
-    return Error(InvalidRecord);
-  return error_code();
+    return Error(BitcodeError::InvalidRecord);
+  return std::error_code();
 }
 
-error_code BitcodeReader::GlobalCleanup() {
+std::error_code BitcodeReader::GlobalCleanup() {
   // Patch the initializers for globals and aliases up.
   ResolveGlobalAndAliasInits();
   if (!GlobalInits.empty() || !AliasInits.empty())
-    return Error(MalformedGlobalInitializerSet);
+    return Error(BitcodeError::MalformedGlobalInitializerSet);
 
   // Look for intrinsic functions which need to be upgraded at some point
   for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
@@ -1681,14 +1858,14 @@ error_code BitcodeReader::GlobalCleanup() {
   // want lazy deserialization.
   std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);
   std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
-  return error_code();
+  return std::error_code();
 }
 
-error_code BitcodeReader::ParseModule(bool Resume) {
+std::error_code BitcodeReader::ParseModule(bool Resume) {
   if (Resume)
     Stream.JumpToBit(NextUnreadBit);
   else if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   SmallVector<uint64_t, 64> Record;
   std::vector<std::string> SectionTable;
@@ -1700,7 +1877,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
       return GlobalCleanup();
 
@@ -1708,37 +1885,37 @@ error_code BitcodeReader::ParseModule(bool Resume) {
       switch (Entry.ID) {
       default:  // Skip unknown content.
         if (Stream.SkipBlock())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         break;
       case bitc::BLOCKINFO_BLOCK_ID:
         if (Stream.ReadBlockInfoBlock())
-          return Error(MalformedBlock);
+          return Error(BitcodeError::MalformedBlock);
         break;
       case bitc::PARAMATTR_BLOCK_ID:
-        if (error_code EC = ParseAttributeBlock())
+        if (std::error_code EC = ParseAttributeBlock())
           return EC;
         break;
       case bitc::PARAMATTR_GROUP_BLOCK_ID:
-        if (error_code EC = ParseAttributeGroupBlock())
+        if (std::error_code EC = ParseAttributeGroupBlock())
           return EC;
         break;
       case bitc::TYPE_BLOCK_ID_NEW:
-        if (error_code EC = ParseTypeTable())
+        if (std::error_code EC = ParseTypeTable())
           return EC;
         break;
       case bitc::VALUE_SYMTAB_BLOCK_ID:
-        if (error_code EC = ParseValueSymbolTable())
+        if (std::error_code EC = ParseValueSymbolTable())
           return EC;
         SeenValueSymbolTable = true;
         break;
       case bitc::CONSTANTS_BLOCK_ID:
-        if (error_code EC = ParseConstants())
+        if (std::error_code EC = ParseConstants())
           return EC;
-        if (error_code EC = ResolveGlobalAndAliasInits())
+        if (std::error_code EC = ResolveGlobalAndAliasInits())
           return EC;
         break;
       case bitc::METADATA_BLOCK_ID:
-        if (error_code EC = ParseMetadata())
+        if (std::error_code EC = ParseMetadata())
           return EC;
         break;
       case bitc::FUNCTION_BLOCK_ID:
@@ -1746,12 +1923,12 @@ error_code BitcodeReader::ParseModule(bool Resume) {
         // FunctionsWithBodies list.
         if (!SeenFirstFunctionBody) {
           std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
-          if (error_code EC = GlobalCleanup())
+          if (std::error_code EC = GlobalCleanup())
             return EC;
           SeenFirstFunctionBody = true;
         }
 
-        if (error_code EC = RememberAndSkipFunctionBody())
+        if (std::error_code EC = RememberAndSkipFunctionBody())
           return EC;
         // For streaming bitcode, suspend parsing when we reach the function
         // bodies. Subsequent materialization calls will resume it when
@@ -1761,11 +1938,11 @@ error_code BitcodeReader::ParseModule(bool Resume) {
         // just finish the parse now.
         if (LazyStreamer && SeenValueSymbolTable) {
           NextUnreadBit = Stream.GetCurrentBitNo();
-          return error_code();
+          return std::error_code();
         }
         break;
       case bitc::USELIST_BLOCK_ID:
-        if (error_code EC = ParseUseLists())
+        if (std::error_code EC = ParseUseLists())
           return EC;
         break;
       }
@@ -1782,12 +1959,12 @@ error_code BitcodeReader::ParseModule(bool Resume) {
     default: break;  // Default behavior, ignore unknown content.
     case bitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
       if (Record.size() < 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       // Only version #0 and #1 are supported so far.
       unsigned module_version = Record[0];
       switch (module_version) {
         default:
-          return Error(InvalidValue);
+          return Error(BitcodeError::InvalidValue);
         case 0:
           UseRelativeIDs = false;
           break;
@@ -1800,21 +1977,21 @@ error_code BitcodeReader::ParseModule(bool Resume) {
     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       TheModule->setTargetTriple(S);
       break;
     }
     case bitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       TheModule->setDataLayout(S);
       break;
     }
     case bitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       TheModule->setModuleInlineAsm(S);
       break;
     }
@@ -1822,35 +1999,49 @@ error_code BitcodeReader::ParseModule(bool Resume) {
       // FIXME: Remove in 4.0.
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       // Ignore value.
       break;
     }
     case bitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SectionTable.push_back(S);
       break;
     }
     case bitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       GCTable.push_back(S);
       break;
     }
+    case bitc::MODULE_CODE_COMDAT: { // COMDAT: [selection_kind, name]
+      if (Record.size() < 2)
+        return Error(BitcodeError::InvalidRecord);
+      Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
+      unsigned ComdatNameSize = Record[1];
+      std::string ComdatName;
+      ComdatName.reserve(ComdatNameSize);
+      for (unsigned i = 0; i != ComdatNameSize; ++i)
+        ComdatName += (char)Record[2 + i];
+      Comdat *C = TheModule->getOrInsertComdat(ComdatName);
+      C->setSelectionKind(SK);
+      ComdatList.push_back(C);
+      break;
+    }
     // GLOBALVAR: [pointer type, isconst, initid,
     //             linkage, alignment, section, visibility, threadlocal,
     //             unnamed_addr, dllstorageclass]
     case bitc::MODULE_CODE_GLOBALVAR: {
       if (Record.size() < 6)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if (!Ty->isPointerTy())
-        return Error(InvalidTypeForValue);
+        return Error(BitcodeError::InvalidTypeForValue);
       unsigned AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
       Ty = cast<PointerType>(Ty)->getElementType();
 
@@ -1860,7 +2051,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
       std::string Section;
       if (Record[5]) {
         if (Record[5]-1 >= SectionTable.size())
-          return Error(InvalidID);
+          return Error(BitcodeError::InvalidID);
         Section = SectionTable[Record[5]-1];
       }
       GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
@@ -1900,23 +2091,29 @@ error_code BitcodeReader::ParseModule(bool Resume) {
       // Remember which value to use for the global initializer.
       if (unsigned InitID = Record[2])
         GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
+
+      if (Record.size() > 11)
+        if (unsigned ComdatID = Record[11]) {
+          assert(ComdatID <= ComdatList.size());
+          NewGV->setComdat(ComdatList[ComdatID - 1]);
+        }
       break;
     }
     // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
     //             alignment, section, visibility, gc, unnamed_addr,
-    //             dllstorageclass]
+    //             prologuedata, dllstorageclass, comdat, prefixdata]
     case bitc::MODULE_CODE_FUNCTION: {
       if (Record.size() < 8)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if (!Ty->isPointerTy())
-        return Error(InvalidTypeForValue);
+        return Error(BitcodeError::InvalidTypeForValue);
       FunctionType *FTy =
         dyn_cast<FunctionType>(cast<PointerType>(Ty)->getElementType());
       if (!FTy)
-        return Error(InvalidTypeForValue);
+        return Error(BitcodeError::InvalidTypeForValue);
 
       Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
                                         "", TheModule);
@@ -1929,7 +2126,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
       Func->setAlignment((1 << Record[5]) >> 1);
       if (Record[6]) {
         if (Record[6]-1 >= SectionTable.size())
-          return Error(InvalidID);
+          return Error(BitcodeError::InvalidID);
         Func->setSection(SectionTable[Record[6]-1]);
       }
       // Local linkage must have default visibility.
@@ -1938,7 +2135,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
         Func->setVisibility(GetDecodedVisibility(Record[7]));
       if (Record.size() > 8 && Record[8]) {
         if (Record[8]-1 > GCTable.size())
-          return Error(InvalidID);
+          return Error(BitcodeError::InvalidID);
         Func->setGC(GCTable[Record[8]-1].c_str());
       }
       bool UnnamedAddr = false;
@@ -1946,20 +2143,31 @@ error_code BitcodeReader::ParseModule(bool Resume) {
         UnnamedAddr = Record[9];
       Func->setUnnamedAddr(UnnamedAddr);
       if (Record.size() > 10 && Record[10] != 0)
-        FunctionPrefixes.push_back(std::make_pair(Func, Record[10]-1));
+        FunctionPrologues.push_back(std::make_pair(Func, Record[10]-1));
 
       if (Record.size() > 11)
         Func->setDLLStorageClass(GetDecodedDLLStorageClass(Record[11]));
       else
         UpgradeDLLImportExportLinkage(Func, Record[3]);
 
+      if (Record.size() > 12)
+        if (unsigned ComdatID = Record[12]) {
+          assert(ComdatID <= ComdatList.size());
+          Func->setComdat(ComdatList[ComdatID - 1]);
+        }
+
+      if (Record.size() > 13 && Record[13] != 0)
+        FunctionPrefixes.push_back(std::make_pair(Func, Record[13]-1));
+
       ValueList.push_back(Func);
 
       // If this is a function with a body, remember the prototype we are
       // creating now, so that we can match up the body with them later.
       if (!isProto) {
+        Func->setIsMaterializable(true);
         FunctionsWithBodies.push_back(Func);
-        if (LazyStreamer) DeferredFunctionInfo[Func] = 0;
+        if (LazyStreamer)
+          DeferredFunctionInfo[Func] = 0;
       }
       break;
     }
@@ -1967,13 +2175,13 @@ error_code BitcodeReader::ParseModule(bool Resume) {
     // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass]
     case bitc::MODULE_CODE_ALIAS: {
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       auto *PTy = dyn_cast<PointerType>(Ty);
       if (!PTy)
-        return Error(InvalidTypeForValue);
+        return Error(BitcodeError::InvalidTypeForValue);
 
       auto *NewGA =
           GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
@@ -1988,9 +2196,9 @@ error_code BitcodeReader::ParseModule(bool Resume) {
       else
         UpgradeDLLImportExportLinkage(NewGA, Record[2]);
       if (Record.size() > 5)
-	NewGA->setThreadLocalMode(GetDecodedThreadLocalMode(Record[5]));
+        NewGA->setThreadLocalMode(GetDecodedThreadLocalMode(Record[5]));
       if (Record.size() > 6)
-	NewGA->setUnnamedAddr(Record[6]);
+        NewGA->setUnnamedAddr(Record[6]);
       ValueList.push_back(NewGA);
       AliasInits.push_back(std::make_pair(NewGA, Record[1]));
       break;
@@ -1999,7 +2207,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
     case bitc::MODULE_CODE_PURGEVALS:
       // Trim down the value list to the specified size.
       if (Record.size() < 1 || Record[0] > ValueList.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       ValueList.shrinkTo(Record[0]);
       break;
     }
@@ -2007,10 +2215,10 @@ error_code BitcodeReader::ParseModule(bool Resume) {
   }
 }
 
-error_code BitcodeReader::ParseBitcodeInto(Module *M) {
+std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
   TheModule = nullptr;
 
-  if (error_code EC = InitStream())
+  if (std::error_code EC = InitStream())
     return EC;
 
   // Sniff for the signature.
@@ -2020,42 +2228,42 @@ error_code BitcodeReader::ParseBitcodeInto(Module *M) {
       Stream.Read(4) != 0xC ||
       Stream.Read(4) != 0xE ||
       Stream.Read(4) != 0xD)
-    return Error(InvalidBitcodeSignature);
+    return Error(BitcodeError::InvalidBitcodeSignature);
 
   // We expect a number of well-defined blocks, though we don't necessarily
   // need to understand them all.
   while (1) {
     if (Stream.AtEndOfStream())
-      return error_code();
+      return std::error_code();
 
     BitstreamEntry Entry =
       Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
 
     case BitstreamEntry::SubBlock:
       switch (Entry.ID) {
       case bitc::BLOCKINFO_BLOCK_ID:
         if (Stream.ReadBlockInfoBlock())
-          return Error(MalformedBlock);
+          return Error(BitcodeError::MalformedBlock);
         break;
       case bitc::MODULE_BLOCK_ID:
         // Reject multiple MODULE_BLOCK's in a single bitstream.
         if (TheModule)
-          return Error(InvalidMultipleBlocks);
+          return Error(BitcodeError::InvalidMultipleBlocks);
         TheModule = M;
-        if (error_code EC = ParseModule(false))
+        if (std::error_code EC = ParseModule(false))
           return EC;
         if (LazyStreamer)
-          return error_code();
+          return std::error_code();
         break;
       default:
         if (Stream.SkipBlock())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         break;
       }
       continue;
@@ -2068,19 +2276,20 @@ error_code BitcodeReader::ParseBitcodeInto(Module *M) {
       if (Stream.getAbbrevIDWidth() == 2 && Entry.ID == 2 &&
           Stream.Read(6) == 2 && Stream.Read(24) == 0xa0a0a &&
           Stream.AtEndOfStream())
-        return error_code();
+        return std::error_code();
 
-      return Error(InvalidRecord);
+      return Error(BitcodeError::InvalidRecord);
     }
   }
 }
 
-error_code BitcodeReader::ParseModuleTriple(std::string &Triple) {
+ErrorOr<std::string> BitcodeReader::parseModuleTriple() {
   if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   SmallVector<uint64_t, 64> Record;
 
+  std::string Triple;
   // Read all the records for this module.
   while (1) {
     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
@@ -2088,9 +2297,9 @@ error_code BitcodeReader::ParseModuleTriple(std::string &Triple) {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return Triple;
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -2102,17 +2311,18 @@ error_code BitcodeReader::ParseModuleTriple(std::string &Triple) {
     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Triple = S;
       break;
     }
     }
     Record.clear();
   }
+  llvm_unreachable("Exit infinite loop");
 }
 
-error_code BitcodeReader::ParseTriple(std::string &Triple) {
-  if (error_code EC = InitStream())
+ErrorOr<std::string> BitcodeReader::parseTriple() {
+  if (std::error_code EC = InitStream())
     return EC;
 
   // Sniff for the signature.
@@ -2122,7 +2332,7 @@ error_code BitcodeReader::ParseTriple(std::string &Triple) {
       Stream.Read(4) != 0xC ||
       Stream.Read(4) != 0xE ||
       Stream.Read(4) != 0xD)
-    return Error(InvalidBitcodeSignature);
+    return Error(BitcodeError::InvalidBitcodeSignature);
 
   // We expect a number of well-defined blocks, though we don't necessarily
   // need to understand them all.
@@ -2131,17 +2341,17 @@ error_code BitcodeReader::ParseTriple(std::string &Triple) {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
 
     case BitstreamEntry::SubBlock:
       if (Entry.ID == bitc::MODULE_BLOCK_ID)
-        return ParseModuleTriple(Triple);
+        return parseModuleTriple();
 
       // Ignore other sub-blocks.
       if (Stream.SkipBlock())
-        return Error(MalformedBlock);
+        return Error(BitcodeError::MalformedBlock);
       continue;
 
     case BitstreamEntry::Record:
@@ -2152,9 +2362,9 @@ error_code BitcodeReader::ParseTriple(std::string &Triple) {
 }
 
 /// ParseMetadataAttachment - Parse metadata attachments.
-error_code BitcodeReader::ParseMetadataAttachment() {
+std::error_code BitcodeReader::ParseMetadataAttachment() {
   if (Stream.EnterSubBlock(bitc::METADATA_ATTACHMENT_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   SmallVector<uint64_t, 64> Record;
   while (1) {
@@ -2163,9 +2373,9 @@ error_code BitcodeReader::ParseMetadataAttachment() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
-      return error_code();
+      return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
       break;
@@ -2179,15 +2389,19 @@ error_code BitcodeReader::ParseMetadataAttachment() {
     case bitc::METADATA_ATTACHMENT: {
       unsigned RecordLength = Record.size();
       if (Record.empty() || (RecordLength - 1) % 2 == 1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Instruction *Inst = InstructionList[Record[0]];
       for (unsigned i = 1; i != RecordLength; i = i+2) {
         unsigned Kind = Record[i];
         DenseMap<unsigned, unsigned>::iterator I =
           MDKindMap.find(Kind);
         if (I == MDKindMap.end())
-          return Error(InvalidID);
-        Value *Node = MDValueList.getValueFwdRef(Record[i+1]);
+          return Error(BitcodeError::InvalidID);
+        Metadata *Node = MDValueList.getValueFwdRef(Record[i + 1]);
+        if (isa<LocalAsMetadata>(Node))
+          // Drop the attachment.  This used to be legal, but there's no
+          // upgrade path.
+          break;
         Inst->setMetadata(I->second, cast<MDNode>(Node));
         if (I->second == LLVMContext::MD_tbaa)
           InstsWithTBAATag.push_back(Inst);
@@ -2199,9 +2413,9 @@ error_code BitcodeReader::ParseMetadataAttachment() {
 }
 
 /// ParseFunctionBody - Lazily parse the specified function body block.
-error_code BitcodeReader::ParseFunctionBody(Function *F) {
+std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
   if (Stream.EnterSubBlock(bitc::FUNCTION_BLOCK_ID))
-    return Error(InvalidRecord);
+    return Error(BitcodeError::InvalidRecord);
 
   InstructionList.clear();
   unsigned ModuleValueListSize = ValueList.size();
@@ -2224,7 +2438,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(MalformedBlock);
+      return Error(BitcodeError::MalformedBlock);
     case BitstreamEntry::EndBlock:
       goto OutOfRecordLoop;
 
@@ -2232,23 +2446,27 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       switch (Entry.ID) {
       default:  // Skip unknown content.
         if (Stream.SkipBlock())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         break;
       case bitc::CONSTANTS_BLOCK_ID:
-        if (error_code EC = ParseConstants())
+        if (std::error_code EC = ParseConstants())
           return EC;
         NextValueNo = ValueList.size();
         break;
       case bitc::VALUE_SYMTAB_BLOCK_ID:
-        if (error_code EC = ParseValueSymbolTable())
+        if (std::error_code EC = ParseValueSymbolTable())
           return EC;
         break;
       case bitc::METADATA_ATTACHMENT_ID:
-        if (error_code EC = ParseMetadataAttachment())
+        if (std::error_code EC = ParseMetadataAttachment())
           return EC;
         break;
       case bitc::METADATA_BLOCK_ID:
-        if (error_code EC = ParseMetadata())
+        if (std::error_code EC = ParseMetadata())
+          return EC;
+        break;
+      case bitc::USELIST_BLOCK_ID:
+        if (std::error_code EC = ParseUseLists())
           return EC;
         break;
       }
@@ -2265,16 +2483,41 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
     switch (BitCode) {
     default: // Default behavior: reject
-      return Error(InvalidValue);
-    case bitc::FUNC_CODE_DECLAREBLOCKS:     // DECLAREBLOCKS: [nblocks]
+      return Error(BitcodeError::InvalidValue);
+    case bitc::FUNC_CODE_DECLAREBLOCKS: {   // DECLAREBLOCKS: [nblocks]
       if (Record.size() < 1 || Record[0] == 0)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       // Create all the basic blocks for the function.
       FunctionBBs.resize(Record[0]);
-      for (unsigned i = 0, e = FunctionBBs.size(); i != e; ++i)
-        FunctionBBs[i] = BasicBlock::Create(Context, "", F);
+
+      // See if anything took the address of blocks in this function.
+      auto BBFRI = BasicBlockFwdRefs.find(F);
+      if (BBFRI == BasicBlockFwdRefs.end()) {
+        for (unsigned i = 0, e = FunctionBBs.size(); i != e; ++i)
+          FunctionBBs[i] = BasicBlock::Create(Context, "", F);
+      } else {
+        auto &BBRefs = BBFRI->second;
+        // Check for invalid basic block references.
+        if (BBRefs.size() > FunctionBBs.size())
+          return Error(BitcodeError::InvalidID);
+        assert(!BBRefs.empty() && "Unexpected empty array");
+        assert(!BBRefs.front() && "Invalid reference to entry block");
+        for (unsigned I = 0, E = FunctionBBs.size(), RE = BBRefs.size(); I != E;
+             ++I)
+          if (I < RE && BBRefs[I]) {
+            BBRefs[I]->insertInto(F);
+            FunctionBBs[I] = BBRefs[I];
+          } else {
+            FunctionBBs[I] = BasicBlock::Create(Context, "", F);
+          }
+
+        // Erase from the table.
+        BasicBlockFwdRefs.erase(BBFRI);
+      }
+
       CurBB = FunctionBBs[0];
       continue;
+    }
 
     case bitc::FUNC_CODE_DEBUG_LOC_AGAIN:  // DEBUG_LOC_AGAIN
       // This record indicates that the last instruction is at the same
@@ -2289,7 +2532,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         I = &FunctionBBs[CurBBNo-1]->back();
 
       if (!I)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I->setDebugLoc(LastLoc);
       I = nullptr;
       continue;
@@ -2302,7 +2545,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
                !FunctionBBs[CurBBNo-1]->empty())
         I = &FunctionBBs[CurBBNo-1]->back();
       if (!I || Record.size() < 4)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       unsigned Line = Record[0], Col = Record[1];
       unsigned ScopeID = Record[2], IAID = Record[3];
@@ -2322,11 +2565,11 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
           OpNum+1 > Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       int Opc = GetDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
       if (Opc == -1)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
       InstructionList.push_back(I);
       if (OpNum < Record.size()) {
@@ -2368,12 +2611,12 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
           OpNum+2 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       Type *ResTy = getTypeByID(Record[OpNum]);
       int Opc = GetDecodedCastOpcode(Record[OpNum+1]);
       if (Opc == -1 || !ResTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Instruction *Temp = nullptr;
       if ((I = UpgradeBitCastInst(Opc, Op, ResTy, Temp))) {
         if (Temp) {
@@ -2391,13 +2634,13 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 0;
       Value *BasePtr;
       if (getValueTypePair(Record, OpNum, NextValueNo, BasePtr))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       SmallVector<Value*, 16> GEPIdx;
       while (OpNum != Record.size()) {
         Value *Op;
         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         GEPIdx.push_back(Op);
       }
 
@@ -2413,14 +2656,14 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 0;
       Value *Agg;
       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       SmallVector<unsigned, 4> EXTRACTVALIdx;
       for (unsigned RecSize = Record.size();
            OpNum != RecSize; ++OpNum) {
         uint64_t Index = Record[OpNum];
         if ((unsigned)Index != Index)
-          return Error(InvalidValue);
+          return Error(BitcodeError::InvalidValue);
         EXTRACTVALIdx.push_back((unsigned)Index);
       }
 
@@ -2434,17 +2677,17 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 0;
       Value *Agg;
       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Value *Val;
       if (getValueTypePair(Record, OpNum, NextValueNo, Val))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       SmallVector<unsigned, 4> INSERTVALIdx;
       for (unsigned RecSize = Record.size();
            OpNum != RecSize; ++OpNum) {
         uint64_t Index = Record[OpNum];
         if ((unsigned)Index != Index)
-          return Error(InvalidValue);
+          return Error(BitcodeError::InvalidValue);
         INSERTVALIdx.push_back((unsigned)Index);
       }
 
@@ -2461,7 +2704,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
           popValue(Record, OpNum, NextValueNo, Type::getInt1Ty(Context), Cond))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       I = SelectInst::Create(Cond, TrueVal, FalseVal);
       InstructionList.push_back(I);
@@ -2476,18 +2719,18 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
           getValueTypePair(Record, OpNum, NextValueNo, Cond))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       // select condition can be either i1 or [N x i1]
       if (VectorType* vector_type =
           dyn_cast<VectorType>(Cond->getType())) {
         // expect <n x i1>
         if (vector_type->getElementType() != Type::getInt1Ty(Context))
-          return Error(InvalidTypeForValue);
+          return Error(BitcodeError::InvalidTypeForValue);
       } else {
         // expect i1
         if (Cond->getType() != Type::getInt1Ty(Context))
-          return Error(InvalidTypeForValue);
+          return Error(BitcodeError::InvalidTypeForValue);
       }
 
       I = SelectInst::Create(Cond, TrueVal, FalseVal);
@@ -2500,7 +2743,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Vec, *Idx;
       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
           getValueTypePair(Record, OpNum, NextValueNo, Idx))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I = ExtractElementInst::Create(Vec, Idx);
       InstructionList.push_back(I);
       break;
@@ -2513,7 +2756,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                    cast<VectorType>(Vec->getType())->getElementType(), Elt) ||
           getValueTypePair(Record, OpNum, NextValueNo, Idx))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I = InsertElementInst::Create(Vec, Elt, Idx);
       InstructionList.push_back(I);
       break;
@@ -2524,10 +2767,10 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Vec1, *Vec2, *Mask;
       if (getValueTypePair(Record, OpNum, NextValueNo, Vec1) ||
           popValue(Record, OpNum, NextValueNo, Vec1->getType(), Vec2))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I = new ShuffleVectorInst(Vec1, Vec2, Mask);
       InstructionList.push_back(I);
       break;
@@ -2545,7 +2788,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
           OpNum+1 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       if (LHS->getType()->isFPOrFPVectorTy())
         I = new FCmpInst((FCmpInst::Predicate)Record[OpNum], LHS, RHS);
@@ -2567,9 +2810,9 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         unsigned OpNum = 0;
         Value *Op = nullptr;
         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         if (OpNum != Record.size())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
 
         I = ReturnInst::Create(Context, Op);
         InstructionList.push_back(I);
@@ -2577,10 +2820,10 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       }
     case bitc::FUNC_CODE_INST_BR: { // BR: [bb#, bb#, opval] or [bb#]
       if (Record.size() != 1 && Record.size() != 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       BasicBlock *TrueDest = getBasicBlock(Record[0]);
       if (!TrueDest)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       if (Record.size() == 1) {
         I = BranchInst::Create(TrueDest);
@@ -2591,7 +2834,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         Value *Cond = getValue(Record, 2, NextValueNo,
                                Type::getInt1Ty(Context));
         if (!FalseDest || !Cond)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         I = BranchInst::Create(TrueDest, FalseDest, Cond);
         InstructionList.push_back(I);
       }
@@ -2611,7 +2854,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
         BasicBlock *Default = getBasicBlock(Record[3]);
         if (!OpTy || !Cond || !Default)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
 
         unsigned NumCases = Record[4];
 
@@ -2663,12 +2906,12 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       // Old SwitchInst format without case ranges.
 
       if (Record.size() < 3 || (Record.size() & 1) == 0)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *OpTy = getTypeByID(Record[0]);
       Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
       BasicBlock *Default = getBasicBlock(Record[2]);
       if (!OpTy || !Cond || !Default)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       unsigned NumCases = (Record.size()-3)/2;
       SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
       InstructionList.push_back(SI);
@@ -2678,7 +2921,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
         if (!CaseVal || !DestBB) {
           delete SI;
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         }
         SI->addCase(CaseVal, DestBB);
       }
@@ -2687,11 +2930,11 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_INDIRECTBR: { // INDIRECTBR: [opty, op0, op1, ...]
       if (Record.size() < 2)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *OpTy = getTypeByID(Record[0]);
       Value *Address = getValue(Record, 1, NextValueNo, OpTy);
       if (!OpTy || !Address)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       unsigned NumDests = Record.size()-2;
       IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
       InstructionList.push_back(IBI);
@@ -2700,7 +2943,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           IBI->addDestination(DestBB);
         } else {
           delete IBI;
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         }
       }
       I = IBI;
@@ -2710,7 +2953,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     case bitc::FUNC_CODE_INST_INVOKE: {
       // INVOKE: [attrs, cc, normBB, unwindBB, fnty, op0,op1,op2, ...]
       if (Record.size() < 4)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       AttributeSet PAL = getAttributes(Record[0]);
       unsigned CCInfo = Record[1];
       BasicBlock *NormalBB = getBasicBlock(Record[2]);
@@ -2719,7 +2962,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 4;
       Value *Callee;
       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
       FunctionType *FTy = !CalleeTy ? nullptr :
@@ -2728,25 +2971,25 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       // Check that the right number of fixed parameters are here.
       if (!FTy || !NormalBB || !UnwindBB ||
           Record.size() < OpNum+FTy->getNumParams())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       SmallVector<Value*, 16> Ops;
       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
         Ops.push_back(getValue(Record, OpNum, NextValueNo,
                                FTy->getParamType(i)));
         if (!Ops.back())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
       }
 
       if (!FTy->isVarArg()) {
         if (Record.size() != OpNum)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
       } else {
         // Read type/value pairs for varargs params.
         while (OpNum != Record.size()) {
           Value *Op;
           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-            return Error(InvalidRecord);
+            return Error(BitcodeError::InvalidRecord);
           Ops.push_back(Op);
         }
       }
@@ -2762,7 +3005,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned Idx = 0;
       Value *Val = nullptr;
       if (getValueTypePair(Record, Idx, NextValueNo, Val))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I = ResumeInst::Create(Val);
       InstructionList.push_back(I);
       break;
@@ -2773,10 +3016,10 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       break;
     case bitc::FUNC_CODE_INST_PHI: { // PHI: [ty, val0,bb0, ...]
       if (Record.size() < 1 || ((Record.size()-1)&1))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       PHINode *PN = PHINode::Create(Ty, (Record.size()-1)/2);
       InstructionList.push_back(PN);
@@ -2792,7 +3035,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           V = getValue(Record, 1+i, NextValueNo, Ty);
         BasicBlock *BB = getBasicBlock(Record[2+i]);
         if (!V || !BB)
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         PN->addIncoming(V, BB);
       }
       I = PN;
@@ -2803,13 +3046,13 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       // LANDINGPAD: [ty, val, val, num, (id0,val0 ...)?]
       unsigned Idx = 0;
       if (Record.size() < 4)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *Ty = getTypeByID(Record[Idx++]);
       if (!Ty)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Value *PersFn = nullptr;
       if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       bool IsCleanup = !!Record[Idx++];
       unsigned NumClauses = Record[Idx++];
@@ -2822,7 +3065,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
         if (getValueTypePair(Record, Idx, NextValueNo, Val)) {
           delete LP;
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
         }
 
         assert((CT != LandingPadInst::Catch ||
@@ -2841,15 +3084,19 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
     case bitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
       if (Record.size() != 4)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       PointerType *Ty =
         dyn_cast_or_null<PointerType>(getTypeByID(Record[0]));
       Type *OpTy = getTypeByID(Record[1]);
       Value *Size = getFnValueByID(Record[2], OpTy);
-      unsigned Align = Record[3];
+      unsigned AlignRecord = Record[3];
+      bool InAlloca = AlignRecord & (1 << 5);
+      unsigned Align = AlignRecord & ((1 << 5) - 1);
       if (!Ty || !Size)
-        return Error(InvalidRecord);
-      I = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
+        return Error(BitcodeError::InvalidRecord);
+      AllocaInst *AI = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
+      AI->setUsedWithInAlloca(InAlloca);
+      I = AI;
       InstructionList.push_back(I);
       break;
     }
@@ -2858,7 +3105,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
           OpNum+2 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1);
       InstructionList.push_back(I);
@@ -2870,15 +3117,14 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
           OpNum+4 != Record.size())
-        return Error(InvalidRecord);
-
+        return Error(BitcodeError::InvalidRecord);
 
       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
       if (Ordering == NotAtomic || Ordering == Release ||
           Ordering == AcquireRelease)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       if (Ordering != NotAtomic && Record[OpNum] == 0)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
 
       I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1,
@@ -2893,7 +3139,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
           OpNum+2 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1);
       InstructionList.push_back(I);
@@ -2907,15 +3153,15 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
           OpNum+4 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
       if (Ordering == NotAtomic || Ordering == Acquire ||
           Ordering == AcquireRelease)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
       if (Ordering != NotAtomic && Record[OpNum] == 0)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1,
                         Ordering, SynchScope);
@@ -2924,7 +3170,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_CMPXCHG: {
       // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, synchscope,
-      //          failureordering]
+      //          failureordering?, isweak?]
       unsigned OpNum = 0;
       Value *Ptr, *Cmp, *New;
       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
@@ -2932,11 +3178,11 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
                     cast<PointerType>(Ptr->getType())->getElementType(), Cmp) ||
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), New) ||
-          (OpNum + 3 != Record.size() && OpNum + 4 != Record.size()))
-        return Error(InvalidRecord);
+          (Record.size() < OpNum + 3 || Record.size() > OpNum + 5))
+        return Error(BitcodeError::InvalidRecord);
       AtomicOrdering SuccessOrdering = GetDecodedOrdering(Record[OpNum+1]);
       if (SuccessOrdering == NotAtomic || SuccessOrdering == Unordered)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+2]);
 
       AtomicOrdering FailureOrdering;
@@ -2949,6 +3195,17 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       I = new AtomicCmpXchgInst(Ptr, Cmp, New, SuccessOrdering, FailureOrdering,
                                 SynchScope);
       cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
+
+      if (Record.size() < 8) {
+        // Before weak cmpxchgs existed, the instruction simply returned the
+        // value loaded from memory, so bitcode files from that era will be
+        // expecting the first component of a modern cmpxchg.
+        CurBB->getInstList().push_back(I);
+        I = ExtractValueInst::Create(I, 0);
+      } else {
+        cast<AtomicCmpXchgInst>(I)->setWeak(Record[OpNum+4]);
+      }
+
       InstructionList.push_back(I);
       break;
     }
@@ -2960,14 +3217,14 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
           OpNum+4 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       AtomicRMWInst::BinOp Operation = GetDecodedRMWOperation(Record[OpNum]);
       if (Operation < AtomicRMWInst::FIRST_BINOP ||
           Operation > AtomicRMWInst::LAST_BINOP)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
       if (Ordering == NotAtomic || Ordering == Unordered)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
       I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SynchScope);
       cast<AtomicRMWInst>(I)->setVolatile(Record[OpNum+1]);
@@ -2976,11 +3233,11 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
       if (2 != Record.size())
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       AtomicOrdering Ordering = GetDecodedOrdering(Record[0]);
       if (Ordering == NotAtomic || Ordering == Unordered ||
           Ordering == Monotonic)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[1]);
       I = new FenceInst(Context, Ordering, SynchScope);
       InstructionList.push_back(I);
@@ -2989,7 +3246,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     case bitc::FUNC_CODE_INST_CALL: {
       // CALL: [paramattrs, cc, fnty, fnid, arg0, arg1...]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       AttributeSet PAL = getAttributes(Record[0]);
       unsigned CCInfo = Record[1];
@@ -2997,13 +3254,13 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 2;
       Value *Callee;
       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
       FunctionType *FTy = nullptr;
       if (OpTy) FTy = dyn_cast<FunctionType>(OpTy->getElementType());
       if (!FTy || Record.size() < FTy->getNumParams()+OpNum)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
 
       SmallVector<Value*, 16> Args;
       // Read the fixed params.
@@ -3014,18 +3271,18 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
           Args.push_back(getValue(Record, OpNum, NextValueNo,
                                   FTy->getParamType(i)));
         if (!Args.back())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
       }
 
       // Read type/value pairs for varargs params.
       if (!FTy->isVarArg()) {
         if (OpNum != Record.size())
-          return Error(InvalidRecord);
+          return Error(BitcodeError::InvalidRecord);
       } else {
         while (OpNum != Record.size()) {
           Value *Op;
           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-            return Error(InvalidRecord);
+            return Error(BitcodeError::InvalidRecord);
           Args.push_back(Op);
         }
       }
@@ -3045,12 +3302,12 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_VAARG: { // VAARG: [valistty, valist, instty]
       if (Record.size() < 3)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       Type *OpTy = getTypeByID(Record[0]);
       Value *Op = getValue(Record, 1, NextValueNo, OpTy);
       Type *ResTy = getTypeByID(Record[2]);
       if (!OpTy || !Op || !ResTy)
-        return Error(InvalidRecord);
+        return Error(BitcodeError::InvalidRecord);
       I = new VAArgInst(Op, ResTy);
       InstructionList.push_back(I);
       break;
@@ -3061,7 +3318,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     // this file.
     if (!CurBB) {
       delete I;
-      return Error(InvalidInstructionWithNoBB);
+      return Error(BitcodeError::InvalidInstructionWithNoBB);
     }
     CurBB->getInstList().push_back(I);
 
@@ -3088,85 +3345,61 @@ OutOfRecordLoop:
           delete A;
         }
       }
-      return Error(NeverResolvedValueFoundInFunction);
+      return Error(BitcodeError::NeverResolvedValueFoundInFunction);
     }
   }
 
   // FIXME: Check for unresolved forward-declared metadata references
   // and clean up leaks.
 
-  // See if anything took the address of blocks in this function.  If so,
-  // resolve them now.
-  DenseMap<Function*, std::vector<BlockAddrRefTy> >::iterator BAFRI =
-    BlockAddrFwdRefs.find(F);
-  if (BAFRI != BlockAddrFwdRefs.end()) {
-    std::vector<BlockAddrRefTy> &RefList = BAFRI->second;
-    for (unsigned i = 0, e = RefList.size(); i != e; ++i) {
-      unsigned BlockIdx = RefList[i].first;
-      if (BlockIdx >= FunctionBBs.size())
-        return Error(InvalidID);
-
-      GlobalVariable *FwdRef = RefList[i].second;
-      FwdRef->replaceAllUsesWith(BlockAddress::get(F, FunctionBBs[BlockIdx]));
-      FwdRef->eraseFromParent();
-    }
-
-    BlockAddrFwdRefs.erase(BAFRI);
-  }
-
   // Trim the value list down to the size it was before we parsed this function.
   ValueList.shrinkTo(ModuleValueListSize);
   MDValueList.shrinkTo(ModuleMDValueListSize);
   std::vector<BasicBlock*>().swap(FunctionBBs);
-  return error_code();
+  return std::error_code();
 }
 
 /// Find the function body in the bitcode stream
-error_code BitcodeReader::FindFunctionInStream(Function *F,
-       DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator) {
+std::error_code BitcodeReader::FindFunctionInStream(
+    Function *F,
+    DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator) {
   while (DeferredFunctionInfoIterator->second == 0) {
     if (Stream.AtEndOfStream())
-      return Error(CouldNotFindFunctionInStream);
+      return Error(BitcodeError::CouldNotFindFunctionInStream);
     // ParseModule will parse the next body in the stream and set its
     // position in the DeferredFunctionInfo map.
-    if (error_code EC = ParseModule(true))
+    if (std::error_code EC = ParseModule(true))
       return EC;
   }
-  return error_code();
+  return std::error_code();
 }
 
 //===----------------------------------------------------------------------===//
 // GVMaterializer implementation
 //===----------------------------------------------------------------------===//
 
+void BitcodeReader::releaseBuffer() { Buffer.release(); }
 
-bool BitcodeReader::isMaterializable(const GlobalValue *GV) const {
-  if (const Function *F = dyn_cast<Function>(GV)) {
-    return F->isDeclaration() &&
-      DeferredFunctionInfo.count(const_cast<Function*>(F));
-  }
-  return false;
-}
-
-error_code BitcodeReader::Materialize(GlobalValue *GV) {
+std::error_code BitcodeReader::materialize(GlobalValue *GV) {
   Function *F = dyn_cast<Function>(GV);
   // If it's not a function or is already material, ignore the request.
   if (!F || !F->isMaterializable())
-    return error_code();
+    return std::error_code();
 
   DenseMap<Function*, uint64_t>::iterator DFII = DeferredFunctionInfo.find(F);
   assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
   // If its position is recorded as 0, its body is somewhere in the stream
   // but we haven't seen it yet.
   if (DFII->second == 0 && LazyStreamer)
-    if (error_code EC = FindFunctionInStream(F, DFII))
+    if (std::error_code EC = FindFunctionInStream(F, DFII))
       return EC;
 
   // Move the bit stream to the saved position of the deferred function body.
   Stream.JumpToBit(DFII->second);
 
-  if (error_code EC = ParseFunctionBody(F))
+  if (std::error_code EC = ParseFunctionBody(F))
     return EC;
+  F->setIsMaterializable(false);
 
   // Upgrade any old intrinsic calls in the function.
   for (UpgradedIntrinsicMap::iterator I = UpgradedIntrinsics.begin(),
@@ -3180,13 +3413,21 @@ error_code BitcodeReader::Materialize(GlobalValue *GV) {
     }
   }
 
-  return error_code();
+  // Bring in any functions that this function forward-referenced via
+  // blockaddresses.
+  return materializeForwardReferencedFunctions();
 }
 
 bool BitcodeReader::isDematerializable(const GlobalValue *GV) const {
   const Function *F = dyn_cast<Function>(GV);
   if (!F || F->isDeclaration())
     return false;
+
+  // Dematerializing F would leave dangling references that wouldn't be
+  // reconnected on re-materialization.
+  if (BlockAddressesTaken.count(F))
+    return false;
+
   return DeferredFunctionInfo.count(const_cast<Function*>(F));
 }
 
@@ -3199,21 +3440,23 @@ void BitcodeReader::Dematerialize(GlobalValue *GV) {
   assert(DeferredFunctionInfo.count(F) && "No info to read function later?");
 
   // Just forget the function body, we can remat it later.
-  F->deleteBody();
+  F->dropAllReferences();
+  F->setIsMaterializable(true);
 }
 
-
-error_code BitcodeReader::MaterializeModule(Module *M) {
+std::error_code BitcodeReader::MaterializeModule(Module *M) {
   assert(M == TheModule &&
          "Can only Materialize the Module this BitcodeReader is attached to.");
+
+  // Promise to materialize all forward references.
+  WillMaterializeAllForwardRefs = true;
+
   // Iterate over the module, deserializing any functions that are still on
   // disk.
   for (Module::iterator F = TheModule->begin(), E = TheModule->end();
        F != E; ++F) {
-    if (F->isMaterializable()) {
-      if (error_code EC = Materialize(F))
-        return EC;
-    }
+    if (std::error_code EC = materialize(F))
+      return EC;
   }
   // At this point, if there are any function bodies, the current bit is
   // pointing to the END_BLOCK record after them. Now make sure the rest
@@ -3221,6 +3464,11 @@ error_code BitcodeReader::MaterializeModule(Module *M) {
   if (NextUnreadBit)
     ParseModule(true);
 
+  // Check that all block address forward references got resolved (as we
+  // promised above).
+  if (!BasicBlockFwdRefs.empty())
+    return Error(BitcodeError::NeverResolvedFunctionFromBlockAddress);
+
   // Upgrade any intrinsic calls that slipped through (should not happen!) and
   // delete the old functions to clean up. We can't do this unless the entire
   // module is materialized because there could always be another function body
@@ -3244,51 +3492,51 @@ error_code BitcodeReader::MaterializeModule(Module *M) {
     UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
 
   UpgradeDebugInfo(*M);
-  return error_code();
+  return std::error_code();
+}
+
+std::vector<StructType *> BitcodeReader::getIdentifiedStructTypes() const {
+  return IdentifiedStructTypes;
 }
 
-error_code BitcodeReader::InitStream() {
+std::error_code BitcodeReader::InitStream() {
   if (LazyStreamer)
     return InitLazyStream();
   return InitStreamFromBuffer();
 }
 
-error_code BitcodeReader::InitStreamFromBuffer() {
+std::error_code BitcodeReader::InitStreamFromBuffer() {
   const unsigned char *BufPtr = (const unsigned char*)Buffer->getBufferStart();
   const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
 
-  if (Buffer->getBufferSize() & 3) {
-    if (!isRawBitcode(BufPtr, BufEnd) && !isBitcodeWrapper(BufPtr, BufEnd))
-      return Error(InvalidBitcodeSignature);
-    else
-      return Error(BitcodeStreamInvalidSize);
-  }
+  if (Buffer->getBufferSize() & 3)
+    return Error(BitcodeError::InvalidBitcodeSignature);
 
   // If we have a wrapper header, parse it and ignore the non-bc file contents.
   // The magic number is 0x0B17C0DE stored in little endian.
   if (isBitcodeWrapper(BufPtr, BufEnd))
     if (SkipBitcodeWrapperHeader(BufPtr, BufEnd, true))
-      return Error(InvalidBitcodeWrapperHeader);
+      return Error(BitcodeError::InvalidBitcodeWrapperHeader);
 
   StreamFile.reset(new BitstreamReader(BufPtr, BufEnd));
-  Stream.init(*StreamFile);
+  Stream.init(&*StreamFile);
 
-  return error_code();
+  return std::error_code();
 }
 
-error_code BitcodeReader::InitLazyStream() {
+std::error_code BitcodeReader::InitLazyStream() {
   // Check and strip off the bitcode wrapper; BitstreamReader expects never to
   // see it.
   StreamingMemoryObject *Bytes = new StreamingMemoryObject(LazyStreamer);
   StreamFile.reset(new BitstreamReader(Bytes));
-  Stream.init(*StreamFile);
+  Stream.init(&*StreamFile);
 
   unsigned char buf[16];
-  if (Bytes->readBytes(0, 16, buf) == -1)
-    return Error(BitcodeStreamInvalidSize);
+  if (Bytes->readBytes(buf, 16, 0) != 16)
+    return Error(BitcodeError::InvalidBitcodeSignature);
 
   if (!isBitcode(buf, buf + 16))
-    return Error(InvalidBitcodeSignature);
+    return Error(BitcodeError::InvalidBitcodeSignature);
 
   if (isBitcodeWrapper(buf, buf + 4)) {
     const unsigned char *bitcodeStart = buf;
@@ -3297,7 +3545,7 @@ error_code BitcodeReader::InitLazyStream() {
     Bytes->dropLeadingBytes(bitcodeStart - buf);
     Bytes->setKnownObjectSize(bitcodeEnd - bitcodeStart);
   }
-  return error_code();
+  return std::error_code();
 }
 
 namespace {
@@ -3306,45 +3554,45 @@ class BitcodeErrorCategoryType : public std::error_category {
     return "llvm.bitcode";
   }
   std::string message(int IE) const override {
-    BitcodeReader::ErrorType E = static_cast<BitcodeReader::ErrorType>(IE);
+    BitcodeError E = static_cast<BitcodeError>(IE);
     switch (E) {
-    case BitcodeReader::BitcodeStreamInvalidSize:
-      return "Bitcode stream length should be >= 16 bytes and a multiple of 4";
-    case BitcodeReader::ConflictingMETADATA_KINDRecords:
+    case BitcodeError::ConflictingMETADATA_KINDRecords:
       return "Conflicting METADATA_KIND records";
-    case BitcodeReader::CouldNotFindFunctionInStream:
+    case BitcodeError::CouldNotFindFunctionInStream:
       return "Could not find function in stream";
-    case BitcodeReader::ExpectedConstant:
+    case BitcodeError::ExpectedConstant:
       return "Expected a constant";
-    case BitcodeReader::InsufficientFunctionProtos:
+    case BitcodeError::InsufficientFunctionProtos:
       return "Insufficient function protos";
-    case BitcodeReader::InvalidBitcodeSignature:
+    case BitcodeError::InvalidBitcodeSignature:
       return "Invalid bitcode signature";
-    case BitcodeReader::InvalidBitcodeWrapperHeader:
+    case BitcodeError::InvalidBitcodeWrapperHeader:
       return "Invalid bitcode wrapper header";
-    case BitcodeReader::InvalidConstantReference:
+    case BitcodeError::InvalidConstantReference:
       return "Invalid ronstant reference";
-    case BitcodeReader::InvalidID:
+    case BitcodeError::InvalidID:
       return "Invalid ID";
-    case BitcodeReader::InvalidInstructionWithNoBB:
+    case BitcodeError::InvalidInstructionWithNoBB:
       return "Invalid instruction with no BB";
-    case BitcodeReader::InvalidRecord:
+    case BitcodeError::InvalidRecord:
       return "Invalid record";
-    case BitcodeReader::InvalidTypeForValue:
+    case BitcodeError::InvalidTypeForValue:
       return "Invalid type for value";
-    case BitcodeReader::InvalidTYPETable:
+    case BitcodeError::InvalidTYPETable:
       return "Invalid TYPE table";
-    case BitcodeReader::InvalidType:
+    case BitcodeError::InvalidType:
       return "Invalid type";
-    case BitcodeReader::MalformedBlock:
+    case BitcodeError::MalformedBlock:
       return "Malformed block";
-    case BitcodeReader::MalformedGlobalInitializerSet:
+    case BitcodeError::MalformedGlobalInitializerSet:
       return "Malformed global initializer set";
-    case BitcodeReader::InvalidMultipleBlocks:
+    case BitcodeError::InvalidMultipleBlocks:
       return "Invalid multiple blocks";
-    case BitcodeReader::NeverResolvedValueFoundInFunction:
+    case BitcodeError::NeverResolvedValueFoundInFunction:
       return "Never resolved value found in function";
-    case BitcodeReader::InvalidValue:
+    case BitcodeError::NeverResolvedFunctionFromBlockAddress:
+      return "Never resolved function from blockaddress";
+    case BitcodeError::InvalidValue:
       return "Invalid value";
     }
     llvm_unreachable("Unknown error type!");
@@ -3352,34 +3600,54 @@ class BitcodeErrorCategoryType : public std::error_category {
 };
 }
 
-const std::error_category &BitcodeReader::BitcodeErrorCategory() {
-  static BitcodeErrorCategoryType O;
-  return O;
+static ManagedStatic<BitcodeErrorCategoryType> ErrorCategory;
+
+const std::error_category &llvm::BitcodeErrorCategory() {
+  return *ErrorCategory;
 }
 
 //===----------------------------------------------------------------------===//
 // External interface
 //===----------------------------------------------------------------------===//
 
-/// getLazyBitcodeModule - lazy function-at-a-time loading from a file.
+/// \brief Get a lazy one-at-time loading module from bitcode.
 ///
-ErrorOr<Module *> llvm::getLazyBitcodeModule(MemoryBuffer *Buffer,
-                                             LLVMContext &Context) {
+/// This isn't always used in a lazy context.  In particular, it's also used by
+/// \a parseBitcodeFile().  If this is truly lazy, then we need to eagerly pull
+/// in forward-referenced functions from block address references.
+///
+/// \param[in] WillMaterializeAll Set to \c true if the caller promises to
+/// materialize everything -- in particular, if this isn't truly lazy.
+static ErrorOr<Module *>
+getLazyBitcodeModuleImpl(std::unique_ptr<MemoryBuffer> &&Buffer,
+                         LLVMContext &Context, bool WillMaterializeAll) {
   Module *M = new Module(Buffer->getBufferIdentifier(), Context);
-  BitcodeReader *R = new BitcodeReader(Buffer, Context);
+  BitcodeReader *R = new BitcodeReader(Buffer.get(), Context);
   M->setMaterializer(R);
-  if (error_code EC = R->ParseBitcodeInto(M)) {
+
+  auto cleanupOnError = [&](std::error_code EC) {
+    R->releaseBuffer(); // Never take ownership on error.
     delete M;  // Also deletes R.
     return EC;
-  }
-  // Have the BitcodeReader dtor delete 'Buffer'.
-  R->setBufferOwned(true);
+  };
 
-  R->materializeForwardReferencedFunctions();
+  if (std::error_code EC = R->ParseBitcodeInto(M))
+    return cleanupOnError(EC);
 
+  if (!WillMaterializeAll)
+    // Resolve forward references from blockaddresses.
+    if (std::error_code EC = R->materializeForwardReferencedFunctions())
+      return cleanupOnError(EC);
+
+  Buffer.release(); // The BitcodeReader owns it now.
   return M;
 }
 
+ErrorOr<Module *>
+llvm::getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
+                           LLVMContext &Context) {
+  return getLazyBitcodeModuleImpl(std::move(Buffer), Context, false);
+}
 
 Module *llvm::getStreamedBitcodeModule(const std::string &name,
                                        DataStreamer *streamer,
@@ -3388,29 +3656,25 @@ Module *llvm::getStreamedBitcodeModule(const std::string &name,
   Module *M = new Module(name, Context);
   BitcodeReader *R = new BitcodeReader(streamer, Context);
   M->setMaterializer(R);
-  if (error_code EC = R->ParseBitcodeInto(M)) {
+  if (std::error_code EC = R->ParseBitcodeInto(M)) {
     if (ErrMsg)
       *ErrMsg = EC.message();
     delete M;  // Also deletes R.
     return nullptr;
   }
-  R->setBufferOwned(false); // no buffer to delete
   return M;
 }
 
-ErrorOr<Module *> llvm::parseBitcodeFile(MemoryBuffer *Buffer,
+ErrorOr<Module *> llvm::parseBitcodeFile(MemoryBufferRef Buffer,
                                          LLVMContext &Context) {
-  ErrorOr<Module *> ModuleOrErr = getLazyBitcodeModule(Buffer, Context);
+  std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
+  ErrorOr<Module *> ModuleOrErr =
+      getLazyBitcodeModuleImpl(std::move(Buf), Context, true);
   if (!ModuleOrErr)
     return ModuleOrErr;
   Module *M = ModuleOrErr.get();
-
-  // Don't let the BitcodeReader dtor delete 'Buffer', regardless of whether
-  // there was an error.
-  static_cast<BitcodeReader*>(M->getMaterializer())->setBufferOwned(false);
-
   // Read in the entire module, and destroy the BitcodeReader.
-  if (error_code EC = M->materializeAllPermanently()) {
+  if (std::error_code EC = M->materializeAllPermanently()) {
     delete M;
     return EC;
   }
@@ -3421,18 +3685,12 @@ ErrorOr<Module *> llvm::parseBitcodeFile(MemoryBuffer *Buffer,
   return M;
 }
 
-std::string llvm::getBitcodeTargetTriple(MemoryBuffer *Buffer,
-                                         LLVMContext& Context,
-                                         std::string *ErrMsg) {
-  BitcodeReader *R = new BitcodeReader(Buffer, Context);
-  // Don't let the BitcodeReader dtor delete 'Buffer'.
-  R->setBufferOwned(false);
-
-  std::string Triple("");
-  if (error_code EC = R->ParseTriple(Triple))
-    if (ErrMsg)
-      *ErrMsg = EC.message();
-
-  delete R;
-  return Triple;
+std::string llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer,
+                                         LLVMContext &Context) {
+  std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
+  auto R = llvm::make_unique<BitcodeReader>(Buf.release(), Context);
+  ErrorOr<std::string> Triple = R->parseTriple();
+  if (Triple.getError())
+    return "";
+  return Triple.get();
 }