diff --git a/include/llvm/Bitcode/ReaderWriter.h b/include/llvm/Bitcode/ReaderWriter.h
index 9a30fb4fdca..48bdabc8839 100644
--- a/include/llvm/Bitcode/ReaderWriter.h
+++ b/include/llvm/Bitcode/ReaderWriter.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_BITCODE_READERWRITER_H
 #define LLVM_BITCODE_READERWRITER_H
 
+#include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include <memory>
@@ -30,24 +31,28 @@ namespace llvm {
   /// Read the header of the specified bitcode buffer and prepare for lazy
   /// deserialization of function bodies.  If successful, this moves Buffer. On
   /// error, this *does not* move Buffer.
-  ErrorOr<Module *> getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
-                                         LLVMContext &Context);
+  ErrorOr<Module *>
+  getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
+                       LLVMContext &Context,
+                       DiagnosticHandlerFunction DiagnosticHandler = nullptr);
 
   /// Read the header of the specified stream and prepare for lazy
   /// deserialization and streaming of function bodies.
-  ErrorOr<std::unique_ptr<Module>>
-  getStreamedBitcodeModule(StringRef Name, DataStreamer *Streamer,
-                           LLVMContext &Context);
+  ErrorOr<std::unique_ptr<Module>> getStreamedBitcodeModule(
+      StringRef Name, DataStreamer *Streamer, LLVMContext &Context,
+      DiagnosticHandlerFunction DiagnosticHandler = nullptr);
 
   /// Read the header of the specified bitcode buffer and extract just the
   /// triple information. If successful, this returns a string. On error, this
   /// returns "".
-  std::string getBitcodeTargetTriple(MemoryBufferRef Buffer,
-                                     LLVMContext &Context);
+  std::string
+  getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
+                         DiagnosticHandlerFunction DiagnosticHandler = nullptr);
 
   /// Read the specified bitcode file, returning the module.
-  ErrorOr<Module *> parseBitcodeFile(MemoryBufferRef Buffer,
-                                     LLVMContext &Context);
+  ErrorOr<Module *>
+  parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
+                   DiagnosticHandlerFunction DiagnosticHandler = nullptr);
 
   /// WriteBitcodeToFile - Write the specified module to the specified
   /// raw output stream.  For streams where it matters, the given stream
@@ -138,32 +143,26 @@ namespace llvm {
   }
 
   const std::error_category &BitcodeErrorCategory();
-  enum class BitcodeError {
-    ConflictingMETADATA_KINDRecords,
-    CouldNotFindFunctionInStream,
-    ExpectedConstant,
-    InsufficientFunctionProtos,
-    InvalidBitcodeSignature,
-    InvalidBitcodeWrapperHeader,
-    InvalidConstantReference,
-    InvalidID, // A read identifier is not found in the table it should be in.
-    InvalidInstructionWithNoBB,
-    InvalidRecord, // A read record doesn't have the expected size or structure
-    InvalidTypeForValue, // Type read OK, but is invalid for its use
-    InvalidTYPETable,
-    InvalidType,    // We were unable to read a type
-    MalformedBlock, // We are unable to advance in the stream.
-    MalformedGlobalInitializerSet,
-    InvalidMultipleBlocks, // We found multiple blocks of a kind that should
-                           // have only one
-    NeverResolvedValueFoundInFunction,
-    NeverResolvedFunctionFromBlockAddress,
-    InvalidValue // Invalid version, inst number, attr number, etc
-  };
+  enum class BitcodeError { InvalidBitcodeSignature, CorruptedBitcode };
   inline std::error_code make_error_code(BitcodeError E) {
     return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
   }
 
+  class BitcodeDiagnosticInfo : public DiagnosticInfo {
+    const Twine &Msg;
+    std::error_code EC;
+
+  public:
+    BitcodeDiagnosticInfo(std::error_code EC, DiagnosticSeverity Severity,
+                          const Twine &Msg);
+    void print(DiagnosticPrinter &DP) const override;
+    std::error_code getError() const { return EC; };
+
+    static bool classof(const DiagnosticInfo *DI) {
+      return DI->getKind() == DK_Bitcode;
+    }
+  };
+
 } // End llvm namespace
 
 namespace std {
diff --git a/include/llvm/IR/DiagnosticInfo.h b/include/llvm/IR/DiagnosticInfo.h
index b592f890b22..c6a8854e077 100644
--- a/include/llvm/IR/DiagnosticInfo.h
+++ b/include/llvm/IR/DiagnosticInfo.h
@@ -45,6 +45,7 @@ enum DiagnosticSeverity {
 /// \brief Defines the different supported kind of a diagnostic.
 /// This enum should be extended with a new ID for each added concrete subclass.
 enum DiagnosticKind {
+  DK_Bitcode,
   DK_InlineAsm,
   DK_StackSize,
   DK_Linker,
@@ -97,6 +98,8 @@ public:
   virtual void print(DiagnosticPrinter &DP) const = 0;
 };
 
+typedef std::function<void(const DiagnosticInfo &)> DiagnosticHandlerFunction;
+
 /// Diagnostic information for inline asm reporting.
 /// This is basically a message and an optional location.
 class DiagnosticInfoInlineAsm : public DiagnosticInfo {
diff --git a/include/llvm/Linker/Linker.h b/include/llvm/Linker/Linker.h
index 1de4488b33b..9c3ecea590b 100644
--- a/include/llvm/Linker/Linker.h
+++ b/include/llvm/Linker/Linker.h
@@ -13,11 +13,9 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
-
-#include <functional>
+#include "llvm/IR/DiagnosticInfo.h"
 
 namespace llvm {
-class DiagnosticInfo;
 class Module;
 class StructType;
 class Type;
@@ -28,8 +26,6 @@ class Type;
 /// something with it after the linking.
 class Linker {
 public:
-  typedef std::function<void(const DiagnosticInfo &)> DiagnosticHandlerFunction;
-
   struct StructTypeKeyInfo {
     struct KeyTy {
       ArrayRef<Type *> ETypes;
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index c28a1333632..75d311c0386 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -15,6 +15,7 @@
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/LLVMContext.h"
@@ -33,6 +34,61 @@ enum {
   SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
 };
 
+BitcodeDiagnosticInfo::BitcodeDiagnosticInfo(std::error_code EC,
+                                             DiagnosticSeverity Severity,
+                                             const Twine &Msg)
+    : DiagnosticInfo(DK_Bitcode, Severity), Msg(Msg), EC(EC) {}
+
+void BitcodeDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
+
+static std::error_code Error(DiagnosticHandlerFunction DiagnosticHandler,
+                             std::error_code EC, const Twine &Message) {
+  BitcodeDiagnosticInfo DI(EC, DS_Error, Message);
+  DiagnosticHandler(DI);
+  return EC;
+}
+
+static std::error_code Error(DiagnosticHandlerFunction DiagnosticHandler,
+                             std::error_code EC) {
+  return Error(DiagnosticHandler, EC, EC.message());
+}
+
+std::error_code BitcodeReader::Error(BitcodeError E, const Twine &Message) {
+  return ::Error(DiagnosticHandler, make_error_code(E), Message);
+}
+
+std::error_code BitcodeReader::Error(const Twine &Message) {
+  return ::Error(DiagnosticHandler,
+                 make_error_code(BitcodeError::CorruptedBitcode), Message);
+}
+
+std::error_code BitcodeReader::Error(BitcodeError E) {
+  return ::Error(DiagnosticHandler, make_error_code(E));
+}
+
+static DiagnosticHandlerFunction getDiagHandler(DiagnosticHandlerFunction F,
+                                                LLVMContext &C) {
+  if (F)
+    return F;
+  return [&C](const DiagnosticInfo &DI) { C.diagnose(DI); };
+}
+
+BitcodeReader::BitcodeReader(MemoryBuffer *buffer, LLVMContext &C,
+                             DiagnosticHandlerFunction DiagnosticHandler)
+    : Context(C), DiagnosticHandler(getDiagHandler(DiagnosticHandler, C)),
+      TheModule(nullptr), Buffer(buffer), LazyStreamer(nullptr),
+      NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
+      MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
+      WillMaterializeAllForwardRefs(false) {}
+
+BitcodeReader::BitcodeReader(DataStreamer *streamer, LLVMContext &C,
+                             DiagnosticHandlerFunction DiagnosticHandler)
+    : Context(C), DiagnosticHandler(getDiagHandler(DiagnosticHandler, C)),
+      TheModule(nullptr), Buffer(nullptr), LazyStreamer(streamer),
+      NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
+      MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
+      WillMaterializeAllForwardRefs(false) {}
+
 std::error_code BitcodeReader::materializeForwardReferencedFunctions() {
   if (WillMaterializeAllForwardRefs)
     return std::error_code();
@@ -53,7 +109,7 @@ std::error_code BitcodeReader::materializeForwardReferencedFunctions() {
     // 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);
+      return Error("Never resolved function from blockaddress");
 
     // Try to materialize F.
     if (std::error_code EC = materialize(F))
@@ -560,10 +616,10 @@ static void decodeLLVMAttributesForBitcode(AttrBuilder &B,
 
 std::error_code BitcodeReader::ParseAttributeBlock() {
   if (Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   if (!MAttributes.empty())
-    return Error(BitcodeError::InvalidMultipleBlocks);
+    return Error("Invalid multiple blocks");
 
   SmallVector<uint64_t, 64> Record;
 
@@ -576,7 +632,7 @@ std::error_code BitcodeReader::ParseAttributeBlock() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
     case BitstreamEntry::Record:
@@ -592,7 +648,7 @@ std::error_code BitcodeReader::ParseAttributeBlock() {
     case bitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...]
       // FIXME: Remove in 4.0.
       if (Record.size() & 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
         AttrBuilder B;
@@ -710,16 +766,17 @@ std::error_code BitcodeReader::ParseAttrKind(uint64_t Code,
                                              Attribute::AttrKind *Kind) {
   *Kind = GetAttrFromCode(Code);
   if (*Kind == Attribute::None)
-    return Error(BitcodeError::InvalidValue);
+    return Error(BitcodeError::CorruptedBitcode,
+                 "Unknown attribute kind (" + Twine(Code) + ")");
   return std::error_code();
 }
 
 std::error_code BitcodeReader::ParseAttributeGroupBlock() {
   if (Stream.EnterSubBlock(bitc::PARAMATTR_GROUP_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   if (!MAttributeGroups.empty())
-    return Error(BitcodeError::InvalidMultipleBlocks);
+    return Error("Invalid multiple blocks");
 
   SmallVector<uint64_t, 64> Record;
 
@@ -730,7 +787,7 @@ std::error_code BitcodeReader::ParseAttributeGroupBlock() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
     case BitstreamEntry::Record:
@@ -745,7 +802,7 @@ std::error_code BitcodeReader::ParseAttributeGroupBlock() {
       break;
     case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       uint64_t GrpID = Record[0];
       uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
@@ -800,14 +857,14 @@ std::error_code BitcodeReader::ParseAttributeGroupBlock() {
 
 std::error_code BitcodeReader::ParseTypeTable() {
   if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   return ParseTypeTableBody();
 }
 
 std::error_code BitcodeReader::ParseTypeTableBody() {
   if (!TypeList.empty())
-    return Error(BitcodeError::InvalidMultipleBlocks);
+    return Error("Invalid multiple blocks");
 
   SmallVector<uint64_t, 64> Record;
   unsigned NumRecords = 0;
@@ -821,10 +878,10 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       if (NumRecords != TypeList.size())
-        return Error(BitcodeError::MalformedBlock);
+        return Error("Malformed block");
       return std::error_code();
     case BitstreamEntry::Record:
       // The interesting case.
@@ -836,12 +893,12 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
     Type *ResultTy = nullptr;
     switch (Stream.readRecord(Entry.ID, Record)) {
     default:
-      return Error(BitcodeError::InvalidValue);
+      return Error("Invalid value");
     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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       TypeList.resize(Record[0]);
       continue;
     case bitc::TYPE_CODE_VOID:      // VOID
@@ -876,20 +933,20 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
       break;
     case bitc::TYPE_CODE_INTEGER:   // INTEGER: [width]
       if (Record.size() < 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned AddressSpace = 0;
       if (Record.size() == 2)
         AddressSpace = Record[1];
       ResultTy = getTypeByID(Record[0]);
       if (!ResultTy)
-        return Error(BitcodeError::InvalidType);
+        return Error("Invalid type");
       ResultTy = PointerType::get(ResultTy, AddressSpace);
       break;
     }
@@ -897,7 +954,7 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SmallVector<Type*, 8> ArgTys;
       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
@@ -908,7 +965,7 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
 
       ResultTy = getTypeByID(Record[2]);
       if (!ResultTy || ArgTys.size() < Record.size()-3)
-        return Error(BitcodeError::InvalidType);
+        return Error("Invalid type");
 
       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
       break;
@@ -916,7 +973,7 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
     case bitc::TYPE_CODE_FUNCTION: {
       // FUNCTION: [vararg, retty, paramty x N]
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SmallVector<Type*, 8> ArgTys;
       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
@@ -927,14 +984,14 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
 
       ResultTy = getTypeByID(Record[1]);
       if (!ResultTy || ArgTys.size() < Record.size()-2)
-        return Error(BitcodeError::InvalidType);
+        return Error("Invalid type");
 
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SmallVector<Type*, 8> EltTys;
       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
@@ -943,21 +1000,21 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
           break;
       }
       if (EltTys.size() != Record.size()-1)
-        return Error(BitcodeError::InvalidType);
+        return Error("Invalid type");
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       continue;
 
     case bitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
       if (Record.size() < 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       if (NumRecords >= TypeList.size())
-        return Error(BitcodeError::InvalidTYPETable);
+        return Error("Invalid TYPE table");
 
       // Check to see if this was forward referenced, if so fill in the temp.
       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
@@ -976,17 +1033,17 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
           break;
       }
       if (EltTys.size() != Record.size()-1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Res->setBody(EltTys, Record[0]);
       ResultTy = Res;
       break;
     }
     case bitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
       if (Record.size() != 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       if (NumRecords >= TypeList.size())
-        return Error(BitcodeError::InvalidTYPETable);
+        return Error("Invalid TYPE table");
 
       // Check to see if this was forward referenced, if so fill in the temp.
       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
@@ -1001,24 +1058,24 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
     }
     case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if ((ResultTy = getTypeByID(Record[1])))
         ResultTy = ArrayType::get(ResultTy, Record[0]);
       else
-        return Error(BitcodeError::InvalidType);
+        return Error("Invalid type");
       break;
     case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if ((ResultTy = getTypeByID(Record[1])))
         ResultTy = VectorType::get(ResultTy, Record[0]);
       else
-        return Error(BitcodeError::InvalidType);
+        return Error("Invalid type");
       break;
     }
 
     if (NumRecords >= TypeList.size())
-      return Error(BitcodeError::InvalidTYPETable);
+      return Error("Invalid TYPE table");
     assert(ResultTy && "Didn't read a type?");
     assert(!TypeList[NumRecords] && "Already read type?");
     TypeList[NumRecords++] = ResultTy;
@@ -1027,7 +1084,7 @@ std::error_code BitcodeReader::ParseTypeTableBody() {
 
 std::error_code BitcodeReader::ParseValueSymbolTable() {
   if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
 
@@ -1039,7 +1096,7 @@ std::error_code BitcodeReader::ParseValueSymbolTable() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
     case BitstreamEntry::Record:
@@ -1054,10 +1111,10 @@ std::error_code BitcodeReader::ParseValueSymbolTable() {
       break;
     case bitc::VST_CODE_ENTRY: {  // VST_ENTRY: [valueid, namechar x N]
       if (ConvertToString(Record, 1, ValueName))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned ValueID = Record[0];
       if (ValueID >= ValueList.size() || !ValueList[ValueID])
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Value *V = ValueList[ValueID];
 
       V->setName(StringRef(ValueName.data(), ValueName.size()));
@@ -1066,10 +1123,10 @@ std::error_code BitcodeReader::ParseValueSymbolTable() {
     }
     case bitc::VST_CODE_BBENTRY: {
       if (ConvertToString(Record, 1, ValueName))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       BasicBlock *BB = getBasicBlock(Record[0]);
       if (!BB)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       BB->setName(StringRef(ValueName.data(), ValueName.size()));
       ValueName.clear();
@@ -1083,7 +1140,7 @@ std::error_code BitcodeReader::ParseMetadata() {
   unsigned NextMDValueNo = MDValueList.size();
 
   if (Stream.EnterSubBlock(bitc::METADATA_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
 
@@ -1094,7 +1151,7 @@ std::error_code BitcodeReader::ParseMetadata() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       MDValueList.tryToResolveCycles();
       return std::error_code();
@@ -1126,7 +1183,7 @@ std::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(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         NMD->addOperand(MD);
       }
       break;
@@ -1136,7 +1193,7 @@ std::error_code BitcodeReader::ParseMetadata() {
       // This is a LocalAsMetadata record, the only type of function-local
       // metadata.
       if (Record.size() % 2 == 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       // If this isn't a LocalAsMetadata record, we're dropping it.  This used
       // to be legal, but there's no upgrade path.
@@ -1162,14 +1219,14 @@ std::error_code BitcodeReader::ParseMetadata() {
     case bitc::METADATA_OLD_NODE: {
       // FIXME: Remove in 4.0.
       if (Record.size() % 2 == 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       unsigned Size = Record.size();
       SmallVector<Metadata *, 8> Elts;
       for (unsigned i = 0; i != Size; i += 2) {
         Type *Ty = getTypeByID(Record[i]);
         if (!Ty)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         if (Ty->isMetadataTy())
           Elts.push_back(MDValueList.getValueFwdRef(Record[i+1]));
         else if (!Ty->isVoidTy()) {
@@ -1186,11 +1243,11 @@ std::error_code BitcodeReader::ParseMetadata() {
     }
     case bitc::METADATA_VALUE: {
       if (Record.size() != 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       Type *Ty = getTypeByID(Record[0]);
       if (Ty->isMetadataTy() || Ty->isVoidTy())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       MDValueList.AssignValue(
           ValueAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
@@ -1219,14 +1276,14 @@ std::error_code BitcodeReader::ParseMetadata() {
     }
     case bitc::METADATA_KIND: {
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       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(BitcodeError::ConflictingMETADATA_KINDRecords);
+        return Error("Conflicting METADATA_KIND records");
       break;
     }
     }
@@ -1266,7 +1323,7 @@ std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         GlobalInitWorklist.back().first->setInitializer(C);
       else
-        return Error(BitcodeError::ExpectedConstant);
+        return Error("Expected a constant");
     }
     GlobalInitWorklist.pop_back();
   }
@@ -1279,7 +1336,7 @@ std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         AliasInitWorklist.back().first->setAliasee(C);
       else
-        return Error(BitcodeError::ExpectedConstant);
+        return Error("Expected a constant");
     }
     AliasInitWorklist.pop_back();
   }
@@ -1292,7 +1349,7 @@ std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         FunctionPrefixWorklist.back().first->setPrefixData(C);
       else
-        return Error(BitcodeError::ExpectedConstant);
+        return Error("Expected a constant");
     }
     FunctionPrefixWorklist.pop_back();
   }
@@ -1305,7 +1362,7 @@ std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         FunctionPrologueWorklist.back().first->setPrologueData(C);
       else
-        return Error(BitcodeError::ExpectedConstant);
+        return Error("Expected a constant");
     }
     FunctionPrologueWorklist.pop_back();
   }
@@ -1323,7 +1380,7 @@ static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
 
 std::error_code BitcodeReader::ParseConstants() {
   if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
 
@@ -1336,10 +1393,10 @@ std::error_code BitcodeReader::ParseConstants() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       if (NextCstNo != ValueList.size())
-        return Error(BitcodeError::InvalidConstantReference);
+        return Error("Invalid ronstant reference");
 
       // Once all the constants have been read, go through and resolve forward
       // references.
@@ -1361,9 +1418,9 @@ std::error_code BitcodeReader::ParseConstants() {
       break;
     case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
       if (Record.empty())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if (Record[0] >= TypeList.size() || !TypeList[Record[0]])
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       CurTy = TypeList[Record[0]];
       continue;  // Skip the ValueList manipulation.
     case bitc::CST_CODE_NULL:      // NULL
@@ -1371,12 +1428,12 @@ std::error_code BitcodeReader::ParseConstants() {
       break;
     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
       if (!CurTy->isIntegerTy() || Record.empty())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       APInt VInt = ReadWideAPInt(Record,
                                  cast<IntegerType>(CurTy)->getBitWidth());
@@ -1386,7 +1443,7 @@ std::error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
       if (Record.empty())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if (CurTy->isHalfTy())
         V = ConstantFP::get(Context, APFloat(APFloat::IEEEhalf,
                                              APInt(16, (uint16_t)Record[0])));
@@ -1416,7 +1473,7 @@ std::error_code BitcodeReader::ParseConstants() {
 
     case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
       if (Record.empty())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       unsigned Size = Record.size();
       SmallVector<Constant*, 16> Elts;
@@ -1444,7 +1501,7 @@ std::error_code BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_STRING:    // STRING: [values]
     case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
       if (Record.empty())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       SmallString<16> Elts(Record.begin(), Record.end());
       V = ConstantDataArray::getString(Context, Elts,
@@ -1453,7 +1510,7 @@ std::error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_DATA: {// DATA: [n x value]
       if (Record.empty())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
       unsigned Size = Record.size();
@@ -1498,14 +1555,14 @@ std::error_code BitcodeReader::ParseConstants() {
         else
           V = ConstantDataArray::get(Context, Elts);
       } else {
-        return Error(BitcodeError::InvalidTypeForValue);
+        return Error("Invalid type for value");
       }
       break;
     }
 
     case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
       if (Opc < 0) {
         V = UndefValue::get(CurTy);  // Unknown binop.
@@ -1536,14 +1593,14 @@ std::error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       int Opc = GetDecodedCastOpcode(Record[0]);
       if (Opc < 0) {
         V = UndefValue::get(CurTy);  // Unknown cast.
       } else {
         Type *OpTy = getTypeByID(Record[1]);
         if (!OpTy)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
         V = UpgradeBitCastExpr(Opc, Op, CurTy);
         if (!V) V = ConstantExpr::getCast(Opc, Op, CurTy);
@@ -1553,12 +1610,12 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SmallVector<Constant*, 16> Elts;
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
         Type *ElTy = getTypeByID(Record[i]);
         if (!ElTy)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
       }
       ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
@@ -1569,7 +1626,7 @@ std::error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_SELECT: {  // CE_SELECT: [opval#, opval#, opval#]
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       Type *SelectorTy = Type::getInt1Ty(Context);
 
@@ -1588,22 +1645,22 @@ std::error_code BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_CE_EXTRACTELT
         : { // CE_EXTRACTELT: [opty, opval, opty, opval]
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       VectorType *OpTy =
         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
       if (!OpTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = nullptr;
       if (Record.size() == 4) {
         Type *IdxTy = getTypeByID(Record[2]);
         if (!IdxTy)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       V = ConstantExpr::getExtractElement(Op0, Op1);
       break;
     }
@@ -1611,7 +1668,7 @@ std::error_code BitcodeReader::ParseConstants() {
         : { // CE_INSERTELT: [opval, opval, opty, opval]
       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
       if (Record.size() < 3 || !OpTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
                                                   OpTy->getElementType());
@@ -1619,19 +1676,19 @@ std::error_code BitcodeReader::ParseConstants() {
       if (Record.size() == 4) {
         Type *IdxTy = getTypeByID(Record[2]);
         if (!IdxTy)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
@@ -1645,7 +1702,7 @@ std::error_code BitcodeReader::ParseConstants() {
       VectorType *OpTy =
         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
       if (Record.size() < 4 || !RTy || !OpTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
@@ -1656,10 +1713,10 @@ std::error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
       if (Record.size() < 4)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *OpTy = getTypeByID(Record[0]);
       if (!OpTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
 
@@ -1673,16 +1730,16 @@ std::error_code BitcodeReader::ParseConstants() {
     // FIXME: Remove with the 4.0 release.
     case bitc::CST_CODE_INLINEASM_OLD: {
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned ConstStrSize = Record[2+AsmStrSize];
       if (3+AsmStrSize+ConstStrSize > Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       for (unsigned i = 0; i != AsmStrSize; ++i)
         AsmStr += (char)Record[2+i];
@@ -1697,17 +1754,17 @@ std::error_code BitcodeReader::ParseConstants() {
     // inteldialect).
     case bitc::CST_CODE_INLINEASM: {
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned ConstStrSize = Record[2+AsmStrSize];
       if (3+AsmStrSize+ConstStrSize > Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       for (unsigned i = 0; i != AsmStrSize; ++i)
         AsmStr += (char)Record[2+i];
@@ -1721,14 +1778,14 @@ std::error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_BLOCKADDRESS:{
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *FnTy = getTypeByID(Record[0]);
       if (!FnTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Function *Fn =
         dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
       if (!Fn)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       // Don't let Fn get dematerialized.
       BlockAddressesTaken.insert(Fn);
@@ -1739,12 +1796,12 @@ std::error_code BitcodeReader::ParseConstants() {
       unsigned BBID = Record[2];
       if (!BBID)
         // Invalid reference to entry block.
-        return Error(BitcodeError::InvalidID);
+        return Error("Invalid ID");
       if (!Fn->empty()) {
         Function::iterator BBI = Fn->begin(), BBE = Fn->end();
         for (size_t I = 0, E = BBID; I != E; ++I) {
           if (BBI == BBE)
-            return Error(BitcodeError::InvalidID);
+            return Error("Invalid ID");
           ++BBI;
         }
         BB = BBI;
@@ -1772,7 +1829,7 @@ std::error_code BitcodeReader::ParseConstants() {
 
 std::error_code BitcodeReader::ParseUseLists() {
   if (Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   // Read all the records.
   SmallVector<uint64_t, 64> Record;
@@ -1782,7 +1839,7 @@ std::error_code BitcodeReader::ParseUseLists() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
     case BitstreamEntry::Record:
@@ -1803,7 +1860,7 @@ std::error_code BitcodeReader::ParseUseLists() {
       unsigned RecordLength = Record.size();
       if (RecordLength < 3)
         // Records should have at least an ID and two indexes.
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned ID = Record.back();
       Record.pop_back();
 
@@ -1840,7 +1897,7 @@ std::error_code BitcodeReader::ParseUseLists() {
 std::error_code BitcodeReader::RememberAndSkipFunctionBody() {
   // Get the function we are talking about.
   if (FunctionsWithBodies.empty())
-    return Error(BitcodeError::InsufficientFunctionProtos);
+    return Error("Insufficient function protos");
 
   Function *Fn = FunctionsWithBodies.back();
   FunctionsWithBodies.pop_back();
@@ -1851,7 +1908,7 @@ std::error_code BitcodeReader::RememberAndSkipFunctionBody() {
 
   // Skip over the function block for now.
   if (Stream.SkipBlock())
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
   return std::error_code();
 }
 
@@ -1859,7 +1916,7 @@ std::error_code BitcodeReader::GlobalCleanup() {
   // Patch the initializers for globals and aliases up.
   ResolveGlobalAndAliasInits();
   if (!GlobalInits.empty() || !AliasInits.empty())
-    return Error(BitcodeError::MalformedGlobalInitializerSet);
+    return Error("Malformed global initializer set");
 
   // Look for intrinsic functions which need to be upgraded at some point
   for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
@@ -1888,7 +1945,7 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
   if (Resume)
     Stream.JumpToBit(NextUnreadBit);
   else if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
   std::vector<std::string> SectionTable;
@@ -1900,7 +1957,7 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return GlobalCleanup();
 
@@ -1908,11 +1965,11 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
       switch (Entry.ID) {
       default:  // Skip unknown content.
         if (Stream.SkipBlock())
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         break;
       case bitc::BLOCKINFO_BLOCK_ID:
         if (Stream.ReadBlockInfoBlock())
-          return Error(BitcodeError::MalformedBlock);
+          return Error("Malformed block");
         break;
       case bitc::PARAMATTR_BLOCK_ID:
         if (std::error_code EC = ParseAttributeBlock())
@@ -1982,12 +2039,12 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       // Only version #0 and #1 are supported so far.
       unsigned module_version = Record[0];
       switch (module_version) {
         default:
-          return Error(BitcodeError::InvalidValue);
+          return Error("Invalid value");
         case 0:
           UseRelativeIDs = false;
           break;
@@ -2000,21 +2057,21 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       TheModule->setTargetTriple(S);
       break;
     }
     case bitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       TheModule->setDataLayout(S);
       break;
     }
     case bitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       TheModule->setModuleInlineAsm(S);
       break;
     }
@@ -2022,27 +2079,27 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
       // FIXME: Remove in 4.0.
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       // Ignore value.
       break;
     }
     case bitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SectionTable.push_back(S);
       break;
     }
     case bitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       GCTable.push_back(S);
       break;
     }
     case bitc::MODULE_CODE_COMDAT: { // COMDAT: [selection_kind, name]
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
       unsigned ComdatNameSize = Record[1];
       std::string ComdatName;
@@ -2059,12 +2116,12 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
     //             unnamed_addr, dllstorageclass]
     case bitc::MODULE_CODE_GLOBALVAR: {
       if (Record.size() < 6)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if (!Ty->isPointerTy())
-        return Error(BitcodeError::InvalidTypeForValue);
+        return Error("Invalid type for value");
       unsigned AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
       Ty = cast<PointerType>(Ty)->getElementType();
 
@@ -2074,7 +2131,7 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
       std::string Section;
       if (Record[5]) {
         if (Record[5]-1 >= SectionTable.size())
-          return Error(BitcodeError::InvalidID);
+          return Error("Invalid ID");
         Section = SectionTable[Record[5]-1];
       }
       GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
@@ -2127,16 +2184,16 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
     //             prologuedata, dllstorageclass, comdat, prefixdata]
     case bitc::MODULE_CODE_FUNCTION: {
       if (Record.size() < 8)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if (!Ty->isPointerTy())
-        return Error(BitcodeError::InvalidTypeForValue);
+        return Error("Invalid type for value");
       FunctionType *FTy =
         dyn_cast<FunctionType>(cast<PointerType>(Ty)->getElementType());
       if (!FTy)
-        return Error(BitcodeError::InvalidTypeForValue);
+        return Error("Invalid type for value");
 
       Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
                                         "", TheModule);
@@ -2149,7 +2206,7 @@ std::error_code BitcodeReader::ParseModule(bool Resume) {
       Func->setAlignment((1 << Record[5]) >> 1);
       if (Record[6]) {
         if (Record[6]-1 >= SectionTable.size())
-          return Error(BitcodeError::InvalidID);
+          return Error("Invalid ID");
         Func->setSection(SectionTable[Record[6]-1]);
       }
       // Local linkage must have default visibility.
@@ -2158,7 +2215,7 @@ std::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(BitcodeError::InvalidID);
+          return Error("Invalid ID");
         Func->setGC(GCTable[Record[8]-1].c_str());
       }
       bool UnnamedAddr = false;
@@ -2198,13 +2255,13 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       auto *PTy = dyn_cast<PointerType>(Ty);
       if (!PTy)
-        return Error(BitcodeError::InvalidTypeForValue);
+        return Error("Invalid type for value");
 
       auto *NewGA =
           GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
@@ -2230,7 +2287,7 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       ValueList.shrinkTo(Record[0]);
       break;
     }
@@ -2251,7 +2308,7 @@ std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
       Stream.Read(4) != 0xC ||
       Stream.Read(4) != 0xE ||
       Stream.Read(4) != 0xD)
-    return Error(BitcodeError::InvalidBitcodeSignature);
+    return Error("Invalid bitcode signature");
 
   // We expect a number of well-defined blocks, though we don't necessarily
   // need to understand them all.
@@ -2264,7 +2321,7 @@ std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
 
@@ -2272,12 +2329,12 @@ std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
       switch (Entry.ID) {
       case bitc::BLOCKINFO_BLOCK_ID:
         if (Stream.ReadBlockInfoBlock())
-          return Error(BitcodeError::MalformedBlock);
+          return Error("Malformed block");
         break;
       case bitc::MODULE_BLOCK_ID:
         // Reject multiple MODULE_BLOCK's in a single bitstream.
         if (TheModule)
-          return Error(BitcodeError::InvalidMultipleBlocks);
+          return Error("Invalid multiple blocks");
         TheModule = M;
         if (std::error_code EC = ParseModule(false))
           return EC;
@@ -2286,7 +2343,7 @@ std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
         break;
       default:
         if (Stream.SkipBlock())
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         break;
       }
       continue;
@@ -2301,14 +2358,14 @@ std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
           Stream.AtEndOfStream())
         return std::error_code();
 
-      return Error(BitcodeError::InvalidRecord);
+      return Error("Invalid record");
     }
   }
 }
 
 ErrorOr<std::string> BitcodeReader::parseModuleTriple() {
   if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
 
@@ -2320,7 +2377,7 @@ ErrorOr<std::string> BitcodeReader::parseModuleTriple() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return Triple;
     case BitstreamEntry::Record:
@@ -2334,7 +2391,7 @@ ErrorOr<std::string> BitcodeReader::parseModuleTriple() {
     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
       std::string S;
       if (ConvertToString(Record, 0, S))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Triple = S;
       break;
     }
@@ -2355,7 +2412,7 @@ ErrorOr<std::string> BitcodeReader::parseTriple() {
       Stream.Read(4) != 0xC ||
       Stream.Read(4) != 0xE ||
       Stream.Read(4) != 0xD)
-    return Error(BitcodeError::InvalidBitcodeSignature);
+    return Error("Invalid bitcode signature");
 
   // We expect a number of well-defined blocks, though we don't necessarily
   // need to understand them all.
@@ -2364,7 +2421,7 @@ ErrorOr<std::string> BitcodeReader::parseTriple() {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
 
@@ -2374,7 +2431,7 @@ ErrorOr<std::string> BitcodeReader::parseTriple() {
 
       // Ignore other sub-blocks.
       if (Stream.SkipBlock())
-        return Error(BitcodeError::MalformedBlock);
+        return Error("Malformed block");
       continue;
 
     case BitstreamEntry::Record:
@@ -2387,7 +2444,7 @@ ErrorOr<std::string> BitcodeReader::parseTriple() {
 /// ParseMetadataAttachment - Parse metadata attachments.
 std::error_code BitcodeReader::ParseMetadataAttachment() {
   if (Stream.EnterSubBlock(bitc::METADATA_ATTACHMENT_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
   while (1) {
@@ -2396,7 +2453,7 @@ std::error_code BitcodeReader::ParseMetadataAttachment() {
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       return std::error_code();
     case BitstreamEntry::Record:
@@ -2412,14 +2469,14 @@ std::error_code BitcodeReader::ParseMetadataAttachment() {
     case bitc::METADATA_ATTACHMENT: {
       unsigned RecordLength = Record.size();
       if (Record.empty() || (RecordLength - 1) % 2 == 1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       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(BitcodeError::InvalidID);
+          return Error("Invalid ID");
         Metadata *Node = MDValueList.getValueFwdRef(Record[i + 1]);
         if (isa<LocalAsMetadata>(Node))
           // Drop the attachment.  This used to be legal, but there's no
@@ -2438,7 +2495,7 @@ std::error_code BitcodeReader::ParseMetadataAttachment() {
 /// ParseFunctionBody - Lazily parse the specified function body block.
 std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
   if (Stream.EnterSubBlock(bitc::FUNCTION_BLOCK_ID))
-    return Error(BitcodeError::InvalidRecord);
+    return Error("Invalid record");
 
   InstructionList.clear();
   unsigned ModuleValueListSize = ValueList.size();
@@ -2469,7 +2526,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
     switch (Entry.Kind) {
     case BitstreamEntry::Error:
-      return Error(BitcodeError::MalformedBlock);
+      return Error("Malformed block");
     case BitstreamEntry::EndBlock:
       goto OutOfRecordLoop;
 
@@ -2477,7 +2534,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       switch (Entry.ID) {
       default:  // Skip unknown content.
         if (Stream.SkipBlock())
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         break;
       case bitc::CONSTANTS_BLOCK_ID:
         if (std::error_code EC = ParseConstants())
@@ -2514,10 +2571,10 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
     switch (BitCode) {
     default: // Default behavior: reject
-      return Error(BitcodeError::InvalidValue);
+      return Error("Invalid value");
     case bitc::FUNC_CODE_DECLAREBLOCKS: {   // DECLAREBLOCKS: [nblocks]
       if (Record.size() < 1 || Record[0] == 0)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       // Create all the basic blocks for the function.
       FunctionBBs.resize(Record[0]);
 
@@ -2530,7 +2587,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
         auto &BBRefs = BBFRI->second;
         // Check for invalid basic block references.
         if (BBRefs.size() > FunctionBBs.size())
-          return Error(BitcodeError::InvalidID);
+          return Error("Invalid ID");
         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;
@@ -2556,7 +2613,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       I = getLastInstruction();
 
       if (!I)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I->setDebugLoc(LastLoc);
       I = nullptr;
       continue;
@@ -2564,7 +2621,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
     case bitc::FUNC_CODE_DEBUG_LOC: {      // DEBUG_LOC: [line, col, scope, ia]
       I = getLastInstruction();
       if (!I || Record.size() < 4)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       unsigned Line = Record[0], Col = Record[1];
       unsigned ScopeID = Record[2], IAID = Record[3];
@@ -2584,11 +2641,11 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       int Opc = GetDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
       if (Opc == -1)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
       InstructionList.push_back(I);
       if (OpNum < Record.size()) {
@@ -2630,12 +2687,12 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
           OpNum+2 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       Type *ResTy = getTypeByID(Record[OpNum]);
       int Opc = GetDecodedCastOpcode(Record[OpNum+1]);
       if (Opc == -1 || !ResTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Instruction *Temp = nullptr;
       if ((I = UpgradeBitCastInst(Opc, Op, ResTy, Temp))) {
         if (Temp) {
@@ -2653,13 +2710,13 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 0;
       Value *BasePtr;
       if (getValueTypePair(Record, OpNum, NextValueNo, BasePtr))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       SmallVector<Value*, 16> GEPIdx;
       while (OpNum != Record.size()) {
         Value *Op;
         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         GEPIdx.push_back(Op);
       }
 
@@ -2675,14 +2732,14 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 0;
       Value *Agg;
       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       SmallVector<unsigned, 4> EXTRACTVALIdx;
       for (unsigned RecSize = Record.size();
            OpNum != RecSize; ++OpNum) {
         uint64_t Index = Record[OpNum];
         if ((unsigned)Index != Index)
-          return Error(BitcodeError::InvalidValue);
+          return Error("Invalid value");
         EXTRACTVALIdx.push_back((unsigned)Index);
       }
 
@@ -2696,17 +2753,17 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 0;
       Value *Agg;
       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Value *Val;
       if (getValueTypePair(Record, OpNum, NextValueNo, Val))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       SmallVector<unsigned, 4> INSERTVALIdx;
       for (unsigned RecSize = Record.size();
            OpNum != RecSize; ++OpNum) {
         uint64_t Index = Record[OpNum];
         if ((unsigned)Index != Index)
-          return Error(BitcodeError::InvalidValue);
+          return Error("Invalid value");
         INSERTVALIdx.push_back((unsigned)Index);
       }
 
@@ -2723,7 +2780,7 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       I = SelectInst::Create(Cond, TrueVal, FalseVal);
       InstructionList.push_back(I);
@@ -2738,18 +2795,18 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       // 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(BitcodeError::InvalidTypeForValue);
+          return Error("Invalid type for value");
       } else {
         // expect i1
         if (Cond->getType() != Type::getInt1Ty(Context))
-          return Error(BitcodeError::InvalidTypeForValue);
+          return Error("Invalid type for value");
       }
 
       I = SelectInst::Create(Cond, TrueVal, FalseVal);
@@ -2762,7 +2819,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Vec, *Idx;
       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
           getValueTypePair(Record, OpNum, NextValueNo, Idx))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I = ExtractElementInst::Create(Vec, Idx);
       InstructionList.push_back(I);
       break;
@@ -2775,7 +2832,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                    cast<VectorType>(Vec->getType())->getElementType(), Elt) ||
           getValueTypePair(Record, OpNum, NextValueNo, Idx))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I = InsertElementInst::Create(Vec, Elt, Idx);
       InstructionList.push_back(I);
       break;
@@ -2786,10 +2843,10 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I = new ShuffleVectorInst(Vec1, Vec2, Mask);
       InstructionList.push_back(I);
       break;
@@ -2807,7 +2864,7 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       if (LHS->getType()->isFPOrFPVectorTy())
         I = new FCmpInst((FCmpInst::Predicate)Record[OpNum], LHS, RHS);
@@ -2829,9 +2886,9 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
         unsigned OpNum = 0;
         Value *Op = nullptr;
         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         if (OpNum != Record.size())
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
 
         I = ReturnInst::Create(Context, Op);
         InstructionList.push_back(I);
@@ -2839,10 +2896,10 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       BasicBlock *TrueDest = getBasicBlock(Record[0]);
       if (!TrueDest)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       if (Record.size() == 1) {
         I = BranchInst::Create(TrueDest);
@@ -2853,7 +2910,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
         Value *Cond = getValue(Record, 2, NextValueNo,
                                Type::getInt1Ty(Context));
         if (!FalseDest || !Cond)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         I = BranchInst::Create(TrueDest, FalseDest, Cond);
         InstructionList.push_back(I);
       }
@@ -2873,7 +2930,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
         Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
         BasicBlock *Default = getBasicBlock(Record[3]);
         if (!OpTy || !Cond || !Default)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
 
         unsigned NumCases = Record[4];
 
@@ -2925,12 +2982,12 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       // Old SwitchInst format without case ranges.
 
       if (Record.size() < 3 || (Record.size() & 1) == 0)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *OpTy = getTypeByID(Record[0]);
       Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
       BasicBlock *Default = getBasicBlock(Record[2]);
       if (!OpTy || !Cond || !Default)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned NumCases = (Record.size()-3)/2;
       SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
       InstructionList.push_back(SI);
@@ -2940,7 +2997,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
         BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
         if (!CaseVal || !DestBB) {
           delete SI;
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         }
         SI->addCase(CaseVal, DestBB);
       }
@@ -2949,11 +3006,11 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_INDIRECTBR: { // INDIRECTBR: [opty, op0, op1, ...]
       if (Record.size() < 2)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *OpTy = getTypeByID(Record[0]);
       Value *Address = getValue(Record, 1, NextValueNo, OpTy);
       if (!OpTy || !Address)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       unsigned NumDests = Record.size()-2;
       IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
       InstructionList.push_back(IBI);
@@ -2962,7 +3019,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           IBI->addDestination(DestBB);
         } else {
           delete IBI;
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         }
       }
       I = IBI;
@@ -2972,7 +3029,7 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       AttributeSet PAL = getAttributes(Record[0]);
       unsigned CCInfo = Record[1];
       BasicBlock *NormalBB = getBasicBlock(Record[2]);
@@ -2981,7 +3038,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 4;
       Value *Callee;
       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
       FunctionType *FTy = !CalleeTy ? nullptr :
@@ -2990,25 +3047,25 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       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(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
       }
 
       if (!FTy->isVarArg()) {
         if (Record.size() != OpNum)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
       } else {
         // Read type/value pairs for varargs params.
         while (OpNum != Record.size()) {
           Value *Op;
           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-            return Error(BitcodeError::InvalidRecord);
+            return Error("Invalid record");
           Ops.push_back(Op);
         }
       }
@@ -3024,7 +3081,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned Idx = 0;
       Value *Val = nullptr;
       if (getValueTypePair(Record, Idx, NextValueNo, Val))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I = ResumeInst::Create(Val);
       InstructionList.push_back(I);
       break;
@@ -3035,10 +3092,10 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       PHINode *PN = PHINode::Create(Ty, (Record.size()-1)/2);
       InstructionList.push_back(PN);
@@ -3054,7 +3111,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           V = getValue(Record, 1+i, NextValueNo, Ty);
         BasicBlock *BB = getBasicBlock(Record[2+i]);
         if (!V || !BB)
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         PN->addIncoming(V, BB);
       }
       I = PN;
@@ -3065,13 +3122,13 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       // LANDINGPAD: [ty, val, val, num, (id0,val0 ...)?]
       unsigned Idx = 0;
       if (Record.size() < 4)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *Ty = getTypeByID(Record[Idx++]);
       if (!Ty)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Value *PersFn = nullptr;
       if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       bool IsCleanup = !!Record[Idx++];
       unsigned NumClauses = Record[Idx++];
@@ -3084,7 +3141,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
         if (getValueTypePair(Record, Idx, NextValueNo, Val)) {
           delete LP;
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
         }
 
         assert((CT != LandingPadInst::Catch ||
@@ -3103,7 +3160,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
     case bitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
       if (Record.size() != 4)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       PointerType *Ty =
         dyn_cast_or_null<PointerType>(getTypeByID(Record[0]));
       Type *OpTy = getTypeByID(Record[1]);
@@ -3112,7 +3169,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       bool InAlloca = AlignRecord & (1 << 5);
       unsigned Align = AlignRecord & ((1 << 5) - 1);
       if (!Ty || !Size)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       AllocaInst *AI = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
       AI->setUsedWithInAlloca(InAlloca);
       I = AI;
@@ -3124,7 +3181,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
           OpNum+2 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1);
       InstructionList.push_back(I);
@@ -3136,14 +3193,14 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
           OpNum+4 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
       if (Ordering == NotAtomic || Ordering == Release ||
           Ordering == AcquireRelease)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       if (Ordering != NotAtomic && Record[OpNum] == 0)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
 
       I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1,
@@ -3158,7 +3215,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
           OpNum+2 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1);
       InstructionList.push_back(I);
@@ -3172,15 +3229,15 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
           OpNum+4 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
       if (Ordering == NotAtomic || Ordering == Acquire ||
           Ordering == AcquireRelease)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
       if (Ordering != NotAtomic && Record[OpNum] == 0)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1,
                         Ordering, SynchScope);
@@ -3198,10 +3255,10 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), New) ||
           (Record.size() < OpNum + 3 || Record.size() > OpNum + 5))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       AtomicOrdering SuccessOrdering = GetDecodedOrdering(Record[OpNum+1]);
       if (SuccessOrdering == NotAtomic || SuccessOrdering == Unordered)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+2]);
 
       AtomicOrdering FailureOrdering;
@@ -3236,14 +3293,14 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           popValue(Record, OpNum, NextValueNo,
                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
           OpNum+4 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       AtomicRMWInst::BinOp Operation = GetDecodedRMWOperation(Record[OpNum]);
       if (Operation < AtomicRMWInst::FIRST_BINOP ||
           Operation > AtomicRMWInst::LAST_BINOP)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
       if (Ordering == NotAtomic || Ordering == Unordered)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
       I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SynchScope);
       cast<AtomicRMWInst>(I)->setVolatile(Record[OpNum+1]);
@@ -3252,11 +3309,11 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
       if (2 != Record.size())
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       AtomicOrdering Ordering = GetDecodedOrdering(Record[0]);
       if (Ordering == NotAtomic || Ordering == Unordered ||
           Ordering == Monotonic)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[1]);
       I = new FenceInst(Context, Ordering, SynchScope);
       InstructionList.push_back(I);
@@ -3265,7 +3322,7 @@ std::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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       AttributeSet PAL = getAttributes(Record[0]);
       unsigned CCInfo = Record[1];
@@ -3273,13 +3330,13 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
       unsigned OpNum = 2;
       Value *Callee;
       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       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(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
 
       SmallVector<Value*, 16> Args;
       // Read the fixed params.
@@ -3290,18 +3347,18 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
           Args.push_back(getValue(Record, OpNum, NextValueNo,
                                   FTy->getParamType(i)));
         if (!Args.back())
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
       }
 
       // Read type/value pairs for varargs params.
       if (!FTy->isVarArg()) {
         if (OpNum != Record.size())
-          return Error(BitcodeError::InvalidRecord);
+          return Error("Invalid record");
       } else {
         while (OpNum != Record.size()) {
           Value *Op;
           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
-            return Error(BitcodeError::InvalidRecord);
+            return Error("Invalid record");
           Args.push_back(Op);
         }
       }
@@ -3321,12 +3378,12 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_VAARG: { // VAARG: [valistty, valist, instty]
       if (Record.size() < 3)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       Type *OpTy = getTypeByID(Record[0]);
       Value *Op = getValue(Record, 1, NextValueNo, OpTy);
       Type *ResTy = getTypeByID(Record[2]);
       if (!OpTy || !Op || !ResTy)
-        return Error(BitcodeError::InvalidRecord);
+        return Error("Invalid record");
       I = new VAArgInst(Op, ResTy);
       InstructionList.push_back(I);
       break;
@@ -3337,7 +3394,7 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
     // this file.
     if (!CurBB) {
       delete I;
-      return Error(BitcodeError::InvalidInstructionWithNoBB);
+      return Error("Invalid instruction with no BB");
     }
     CurBB->getInstList().push_back(I);
 
@@ -3364,7 +3421,7 @@ OutOfRecordLoop:
           delete A;
         }
       }
-      return Error(BitcodeError::NeverResolvedValueFoundInFunction);
+      return Error("Never resolved value found in function");
     }
   }
 
@@ -3384,7 +3441,7 @@ std::error_code BitcodeReader::FindFunctionInStream(
     DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator) {
   while (DeferredFunctionInfoIterator->second == 0) {
     if (Stream.AtEndOfStream())
-      return Error(BitcodeError::CouldNotFindFunctionInStream);
+      return Error("Could not find function in stream");
     // ParseModule will parse the next body in the stream and set its
     // position in the DeferredFunctionInfo map.
     if (std::error_code EC = ParseModule(true))
@@ -3486,7 +3543,7 @@ std::error_code BitcodeReader::MaterializeModule(Module *M) {
   // Check that all block address forward references got resolved (as we
   // promised above).
   if (!BasicBlockFwdRefs.empty())
-    return Error(BitcodeError::NeverResolvedFunctionFromBlockAddress);
+    return Error("Never resolved function from blockaddress");
 
   // 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
@@ -3529,13 +3586,13 @@ std::error_code BitcodeReader::InitStreamFromBuffer() {
   const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
 
   if (Buffer->getBufferSize() & 3)
-    return Error(BitcodeError::InvalidBitcodeSignature);
+    return Error("Invalid bitcode signature");
 
   // 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(BitcodeError::InvalidBitcodeWrapperHeader);
+      return Error("Invalid bitcode wrapper header");
 
   StreamFile.reset(new BitstreamReader(BufPtr, BufEnd));
   Stream.init(&*StreamFile);
@@ -3553,10 +3610,10 @@ std::error_code BitcodeReader::InitLazyStream() {
 
   unsigned char buf[16];
   if (Bytes.readBytes(buf, 16, 0) != 16)
-    return Error(BitcodeError::InvalidBitcodeSignature);
+    return Error("Invalid bitcode signature");
 
   if (!isBitcode(buf, buf + 16))
-    return Error(BitcodeError::InvalidBitcodeSignature);
+    return Error("Invalid bitcode signature");
 
   if (isBitcodeWrapper(buf, buf + 4)) {
     const unsigned char *bitcodeStart = buf;
@@ -3576,44 +3633,10 @@ class BitcodeErrorCategoryType : public std::error_category {
   std::string message(int IE) const override {
     BitcodeError E = static_cast<BitcodeError>(IE);
     switch (E) {
-    case BitcodeError::ConflictingMETADATA_KINDRecords:
-      return "Conflicting METADATA_KIND records";
-    case BitcodeError::CouldNotFindFunctionInStream:
-      return "Could not find function in stream";
-    case BitcodeError::ExpectedConstant:
-      return "Expected a constant";
-    case BitcodeError::InsufficientFunctionProtos:
-      return "Insufficient function protos";
     case BitcodeError::InvalidBitcodeSignature:
       return "Invalid bitcode signature";
-    case BitcodeError::InvalidBitcodeWrapperHeader:
-      return "Invalid bitcode wrapper header";
-    case BitcodeError::InvalidConstantReference:
-      return "Invalid ronstant reference";
-    case BitcodeError::InvalidID:
-      return "Invalid ID";
-    case BitcodeError::InvalidInstructionWithNoBB:
-      return "Invalid instruction with no BB";
-    case BitcodeError::InvalidRecord:
-      return "Invalid record";
-    case BitcodeError::InvalidTypeForValue:
-      return "Invalid type for value";
-    case BitcodeError::InvalidTYPETable:
-      return "Invalid TYPE table";
-    case BitcodeError::InvalidType:
-      return "Invalid type";
-    case BitcodeError::MalformedBlock:
-      return "Malformed block";
-    case BitcodeError::MalformedGlobalInitializerSet:
-      return "Malformed global initializer set";
-    case BitcodeError::InvalidMultipleBlocks:
-      return "Invalid multiple blocks";
-    case BitcodeError::NeverResolvedValueFoundInFunction:
-      return "Never resolved value found in function";
-    case BitcodeError::NeverResolvedFunctionFromBlockAddress:
-      return "Never resolved function from blockaddress";
-    case BitcodeError::InvalidValue:
-      return "Invalid value";
+    case BitcodeError::CorruptedBitcode:
+      return "Corrupted bitcode";
     }
     llvm_unreachable("Unknown error type!");
   }
@@ -3640,9 +3663,11 @@ const std::error_category &llvm::BitcodeErrorCategory() {
 /// materialize everything -- in particular, if this isn't truly lazy.
 static ErrorOr<Module *>
 getLazyBitcodeModuleImpl(std::unique_ptr<MemoryBuffer> &&Buffer,
-                         LLVMContext &Context, bool WillMaterializeAll) {
+                         LLVMContext &Context, bool WillMaterializeAll,
+                         DiagnosticHandlerFunction DiagnosticHandler) {
   Module *M = new Module(Buffer->getBufferIdentifier(), Context);
-  BitcodeReader *R = new BitcodeReader(Buffer.get(), Context);
+  BitcodeReader *R =
+      new BitcodeReader(Buffer.get(), Context, DiagnosticHandler);
   M->setMaterializer(R);
 
   auto cleanupOnError = [&](std::error_code EC) {
@@ -3665,26 +3690,30 @@ getLazyBitcodeModuleImpl(std::unique_ptr<MemoryBuffer> &&Buffer,
 
 ErrorOr<Module *>
 llvm::getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
-                           LLVMContext &Context) {
-  return getLazyBitcodeModuleImpl(std::move(Buffer), Context, false);
+                           LLVMContext &Context,
+                           DiagnosticHandlerFunction DiagnosticHandler) {
+  return getLazyBitcodeModuleImpl(std::move(Buffer), Context, false,
+                                  DiagnosticHandler);
 }
 
 ErrorOr<std::unique_ptr<Module>>
 llvm::getStreamedBitcodeModule(StringRef Name, DataStreamer *Streamer,
-                               LLVMContext &Context) {
+                               LLVMContext &Context,
+                               DiagnosticHandlerFunction DiagnosticHandler) {
   std::unique_ptr<Module> M = make_unique<Module>(Name, Context);
-  BitcodeReader *R = new BitcodeReader(Streamer, Context);
+  BitcodeReader *R = new BitcodeReader(Streamer, Context, DiagnosticHandler);
   M->setMaterializer(R);
   if (std::error_code EC = R->ParseBitcodeInto(M.get()))
     return EC;
   return std::move(M);
 }
 
-ErrorOr<Module *> llvm::parseBitcodeFile(MemoryBufferRef Buffer,
-                                         LLVMContext &Context) {
+ErrorOr<Module *>
+llvm::parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
+                       DiagnosticHandlerFunction DiagnosticHandler) {
   std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
-  ErrorOr<Module *> ModuleOrErr =
-      getLazyBitcodeModuleImpl(std::move(Buf), Context, true);
+  ErrorOr<Module *> ModuleOrErr = getLazyBitcodeModuleImpl(
+      std::move(Buf), Context, true, DiagnosticHandler);
   if (!ModuleOrErr)
     return ModuleOrErr;
   Module *M = ModuleOrErr.get();
@@ -3700,10 +3729,12 @@ ErrorOr<Module *> llvm::parseBitcodeFile(MemoryBufferRef Buffer,
   return M;
 }
 
-std::string llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer,
-                                         LLVMContext &Context) {
+std::string
+llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
+                             DiagnosticHandlerFunction DiagnosticHandler) {
   std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
-  auto R = llvm::make_unique<BitcodeReader>(Buf.release(), Context);
+  auto R = llvm::make_unique<BitcodeReader>(Buf.release(), Context,
+                                            DiagnosticHandler);
   ErrorOr<std::string> Triple = R->parseTriple();
   if (Triple.getError())
     return "";
diff --git a/lib/Bitcode/Reader/BitcodeReader.h b/lib/Bitcode/Reader/BitcodeReader.h
index 639ddb90350..7f7eb70bce9 100644
--- a/lib/Bitcode/Reader/BitcodeReader.h
+++ b/lib/Bitcode/Reader/BitcodeReader.h
@@ -132,6 +132,7 @@ public:
 
 class BitcodeReader : public GVMaterializer {
   LLVMContext &Context;
+  DiagnosticHandlerFunction DiagnosticHandler;
   Module *TheModule;
   std::unique_ptr<MemoryBuffer> Buffer;
   std::unique_ptr<BitstreamReader> StreamFile;
@@ -210,18 +211,14 @@ class BitcodeReader : public GVMaterializer {
   SmallPtrSet<const Function *, 4> BlockAddressesTaken;
 
 public:
-  std::error_code Error(BitcodeError E) { return make_error_code(E); }
+  std::error_code Error(BitcodeError E, const Twine &Message);
+  std::error_code Error(BitcodeError E);
+  std::error_code Error(const Twine &Message);
 
-  explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
-      : Context(C), TheModule(nullptr), Buffer(buffer), LazyStreamer(nullptr),
-        NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
-        MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
-        WillMaterializeAllForwardRefs(false) {}
-  explicit BitcodeReader(DataStreamer *streamer, LLVMContext &C)
-      : Context(C), TheModule(nullptr), Buffer(nullptr), LazyStreamer(streamer),
-        NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
-        MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
-        WillMaterializeAllForwardRefs(false) {}
+  explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C,
+                         DiagnosticHandlerFunction DiagnosticHandler);
+  explicit BitcodeReader(DataStreamer *streamer, LLVMContext &C,
+                         DiagnosticHandlerFunction DiagnosticHandler);
   ~BitcodeReader() { FreeState(); }
 
   std::error_code materializeForwardReferencedFunctions();
diff --git a/lib/LTO/LTOModule.cpp b/lib/LTO/LTOModule.cpp
index 8817c35d9d4..8b4a2f4d9ba 100644
--- a/lib/LTO/LTOModule.cpp
+++ b/lib/LTO/LTOModule.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Bitcode/ReaderWriter.h"
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
@@ -146,23 +147,42 @@ LTOModule *LTOModule::createInContext(const void *mem, size_t length,
   return makeLTOModule(Buffer, options, errMsg, Context);
 }
 
-static ErrorOr<Module *> parseBitcodeFileImpl(MemoryBufferRef Buffer,
-                                              LLVMContext &Context,
-                                              bool ShouldBeLazy) {
+static Module *parseBitcodeFileImpl(MemoryBufferRef Buffer,
+                                    LLVMContext &Context, bool ShouldBeLazy,
+                                    std::string &ErrMsg) {
+
   // Find the buffer.
   ErrorOr<MemoryBufferRef> MBOrErr =
       IRObjectFile::findBitcodeInMemBuffer(Buffer);
-  if (std::error_code EC = MBOrErr.getError())
-    return EC;
+  if (std::error_code EC = MBOrErr.getError()) {
+    ErrMsg = EC.message();
+    return nullptr;
+  }
 
-  if (!ShouldBeLazy)
+  std::function<void(const DiagnosticInfo &)> DiagnosticHandler =
+      [&ErrMsg](const DiagnosticInfo &DI) {
+        raw_string_ostream Stream(ErrMsg);
+        DiagnosticPrinterRawOStream DP(Stream);
+        DI.print(DP);
+      };
+
+  if (!ShouldBeLazy) {
     // Parse the full file.
-    return parseBitcodeFile(*MBOrErr, Context);
+    ErrorOr<Module *> M =
+        parseBitcodeFile(*MBOrErr, Context, DiagnosticHandler);
+    if (!M)
+      return nullptr;
+    return *M;
+  }
 
   // Parse lazily.
   std::unique_ptr<MemoryBuffer> LightweightBuf =
       MemoryBuffer::getMemBuffer(*MBOrErr, false);
-  return getLazyBitcodeModule(std::move(LightweightBuf), Context);
+  ErrorOr<Module *> M = getLazyBitcodeModule(std::move(LightweightBuf), Context,
+                                             DiagnosticHandler);
+  if (!M)
+    return nullptr;
+  return *M;
 }
 
 LTOModule *LTOModule::makeLTOModule(MemoryBufferRef Buffer,
@@ -176,13 +196,11 @@ LTOModule *LTOModule::makeLTOModule(MemoryBufferRef Buffer,
 
   // If we own a context, we know this is being used only for symbol
   // extraction, not linking.  Be lazy in that case.
-  ErrorOr<Module *> MOrErr = parseBitcodeFileImpl(
-      Buffer, *Context, /* ShouldBeLazy */ static_cast<bool>(OwnedContext));
-  if (std::error_code EC = MOrErr.getError()) {
-    errMsg = EC.message();
+  std::unique_ptr<Module> M(parseBitcodeFileImpl(
+      Buffer, *Context,
+      /* ShouldBeLazy */ static_cast<bool>(OwnedContext), errMsg));
+  if (!M)
     return nullptr;
-  }
-  std::unique_ptr<Module> M(MOrErr.get());
 
   std::string TripleStr = M->getTargetTriple();
   if (TripleStr.empty())
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 7a8025f897e..767d465d1be 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -420,11 +420,11 @@ class ModuleLinker {
   /// Functions that have replaced other functions.
   SmallPtrSet<const Function *, 16> OverridingFunctions;
 
-  Linker::DiagnosticHandlerFunction DiagnosticHandler;
+  DiagnosticHandlerFunction DiagnosticHandler;
 
 public:
   ModuleLinker(Module *dstM, Linker::IdentifiedStructTypeSet &Set, Module *srcM,
-               Linker::DiagnosticHandlerFunction DiagnosticHandler)
+               DiagnosticHandlerFunction DiagnosticHandler)
       : DstM(dstM), SrcM(srcM), TypeMap(Set),
         ValMaterializer(TypeMap, DstM, LazilyLinkGlobalValues),
         DiagnosticHandler(DiagnosticHandler) {}
diff --git a/test/Bitcode/invalid.ll b/test/Bitcode/invalid.ll
index 1d4a82bf2b6..8b532d8dadf 100644
--- a/test/Bitcode/invalid.ll
+++ b/test/Bitcode/invalid.ll
@@ -1,6 +1,6 @@
 ; RUN:  not llvm-dis < %s.bc 2>&1 | FileCheck %s
 
-; CHECK: llvm-dis{{(\.EXE|\.exe)?}}: Invalid value
+; CHECK: llvm-dis{{(\.EXE|\.exe)?}}: Unknown attribute kind (48)
 
 ; invalid.ll.bc has an invalid attribute number.
 ; The test checks that LLVM reports the error and doesn't access freed memory
diff --git a/test/LTO/invalid.ll b/test/LTO/invalid.ll
index 39b928587db..868155dfb13 100644
--- a/test/LTO/invalid.ll
+++ b/test/LTO/invalid.ll
@@ -1,4 +1,4 @@
 ; RUN: not llvm-lto %S/../Bitcode/invalid.ll.bc 2>&1 | FileCheck %s
 
 
-; CHECK: llvm-lto{{.*}}: error loading file '{{.*}}/../Bitcode/invalid.ll.bc': Invalid value
+; CHECK: llvm-lto{{.*}}: error loading file '{{.*}}/../Bitcode/invalid.ll.bc': Unknown attribute kind (48)
diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index 6b5864457a4..1ba08cc53dc 100644
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -19,6 +19,8 @@
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/CommandFlags.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
@@ -269,6 +271,23 @@ static bool shouldSkip(uint32_t Symflags) {
   return false;
 }
 
+static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
+  assert(DI.getSeverity() == DS_Error && "Only expecting errors");
+  const auto &BDI = cast<BitcodeDiagnosticInfo>(DI);
+  std::error_code EC = BDI.getError();
+  if (EC == BitcodeError::InvalidBitcodeSignature)
+    return;
+
+  std::string ErrStorage;
+  {
+    raw_string_ostream OS(ErrStorage);
+    DiagnosticPrinterRawOStream DP(OS);
+    DI.print(DP);
+  }
+  message(LDPL_FATAL, "LLVM gold plugin has failed to create LTO module: %s",
+          ErrStorage.c_str());
+}
+
 /// Called by gold to see whether this file is one that our plugin can handle.
 /// We'll try to open it and register all the symbols with add_symbol if
 /// possible.
@@ -302,11 +321,11 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
     BufferRef = Buffer->getMemBufferRef();
   }
 
+  Context.setDiagnosticHandler(diagnosticHandler);
   ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
       object::IRObjectFile::create(BufferRef, Context);
   std::error_code EC = ObjOrErr.getError();
-  if (EC == BitcodeError::InvalidBitcodeSignature ||
-      EC == object::object_error::invalid_file_type ||
+  if (EC == object::object_error::invalid_file_type ||
       EC == object::object_error::bitcode_section_not_found)
     return LDPS_OK;
 
diff --git a/tools/llvm-dis/llvm-dis.cpp b/tools/llvm-dis/llvm-dis.cpp
index 072f6369e12..1349ecc85a4 100644
--- a/tools/llvm-dis/llvm-dis.cpp
+++ b/tools/llvm-dis/llvm-dis.cpp
@@ -20,6 +20,8 @@
 #include "llvm/Bitcode/ReaderWriter.h"
 #include "llvm/IR/AssemblyAnnotationWriter.h"
 #include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Type.h"
@@ -112,6 +114,17 @@ public:
 
 } // end anon namespace
 
+static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
+  assert(DI.getSeverity() == DS_Error && "Only expecting errors");
+
+  raw_ostream &OS = errs();
+  OS << (char *)Context << ": ";
+  DiagnosticPrinterRawOStream DP(OS);
+  DI.print(DP);
+  OS << '\n';
+  exit(1);
+}
+
 int main(int argc, char **argv) {
   // Print a stack trace if we signal out.
   sys::PrintStackTraceOnErrorSignal();
@@ -120,6 +133,7 @@ int main(int argc, char **argv) {
   LLVMContext &Context = getGlobalContext();
   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 
+  Context.setDiagnosticHandler(diagnosticHandler, argv[0]);
 
   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
 
@@ -136,25 +150,8 @@ int main(int argc, char **argv) {
       DisplayFilename = InputFilename;
     ErrorOr<std::unique_ptr<Module>> MOrErr =
         getStreamedBitcodeModule(DisplayFilename, Streamer, Context);
-    if (std::error_code EC = MOrErr.getError())
-      ErrorMessage = EC.message();
-    else
-      M = std::move(*MOrErr);
-    if(M.get()) {
-      if (std::error_code EC = M->materializeAllPermanently()) {
-        ErrorMessage = EC.message();
-        M.reset();
-      }
-    }
-  }
-
-  if (!M.get()) {
-    errs() << argv[0] << ": ";
-    if (ErrorMessage.size())
-      errs() << ErrorMessage << "\n";
-    else
-      errs() << "bitcode didn't read correctly.\n";
-    return 1;
+    M = std::move(*MOrErr);
+    M->materializeAllPermanently();
   }
 
   // Just use stdout.  We won't actually print anything on it.