Bitcode: Change module reader functions to return an llvm::Expected.

[mehdi_amini]

LGTM. Thanks.

llvm/unittests/Bitcode/BitReaderTest.cpp

61

Any error was just ignored before? What was the behavior on error?

[pcc]

llvm/unittests/Bitcode/BitReaderTest.cpp

61

It looks like we would just fail the assertion in ErrorOr::getStorage().

clang/lib/CodeGen/CGOpenMPRuntime.cpp

void CGOpenMPRuntime::loadOffloadInfoMetadata() {
   if (CGM.getLangOpts().OMPHostIRFile.empty())
     return;
 
   auto Buf = llvm::MemoryBuffer::getFile(CGM.getLangOpts().OMPHostIRFile);
   if (Buf.getError())
     return;
 
   llvm::LLVMContext C;
-  auto ME = llvm::parseBitcodeFile(Buf.get()->getMemBufferRef(), C);
+  auto ME = expectedToErrorOrAndEmitErrors(
+      C, llvm::parseBitcodeFile(Buf.get()->getMemBufferRef(), C));
 
   if (ME.getError())
     return;
 
   llvm::NamedMDNode *MD = ME.get()->getNamedMetadata("omp_offload.info");
   if (!MD)
     return;
 

clang/lib/CodeGen/CodeGenAction.cpp

for (auto &I : CI.getCodeGenOpts().LinkBitcodeFiles) {
       auto BCBuf = CI.getFileManager().getBufferForFile(LinkBCFile);
       if (!BCBuf) {
         CI.getDiagnostics().Report(diag::err_cannot_open_file)
             << LinkBCFile << BCBuf.getError().message();
         LinkModules.clear();
         return nullptr;
       }
 
-      ErrorOr<std::unique_ptr<llvm::Module>> ModuleOrErr =
+      Expected<std::unique_ptr<llvm::Module>> ModuleOrErr =
           getOwningLazyBitcodeModule(std::move(*BCBuf), *VMContext);
-      if (std::error_code EC = ModuleOrErr.getError()) {
-        CI.getDiagnostics().Report(diag::err_cannot_open_file) << LinkBCFile
-                                                               << EC.message();
+      if (!ModuleOrErr) {
+        handleAllErrors(ModuleOrErr.takeError(), [&](ErrorInfoBase &EIB) {
+          CI.getDiagnostics().Report(diag::err_cannot_open_file)
+              << LinkBCFile << EIB.message();
+        });
         LinkModules.clear();
         return nullptr;
       }
       addLinkModule(ModuleOrErr.get().release(), I.first);
     }
 
   CoverageSourceInfo *CoverageInfo = nullptr;
   // Add the preprocessor callback only when the coverage mapping is generated.

llvm/include/llvm/Bitcode/BitcodeReader.h

ErrorOr<T> expectedToErrorOrAndEmitErrors(LLVMContext &Ctx, Expected<T> Val) {
     if (!Val)
       return errorToErrorCodeAndEmitErrors(Ctx, Val.takeError());
     return std::move(*Val);
   }
 
   /// Read the header of the specified bitcode buffer and prepare for lazy
   /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
   /// lazily load metadata as well.
-  ErrorOr<std::unique_ptr<Module>>
+  Expected<std::unique_ptr<Module>>
   getLazyBitcodeModule(MemoryBufferRef Buffer, LLVMContext &Context,
                        bool ShouldLazyLoadMetadata = false);
 
   /// Like getLazyBitcodeModule, except that the module takes ownership of
   /// the memory buffer if successful. If successful, this moves Buffer. On
   /// error, this *does not* move Buffer.
-  ErrorOr<std::unique_ptr<Module>>
+  Expected<std::unique_ptr<Module>>
   getOwningLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
                              LLVMContext &Context,
                              bool ShouldLazyLoadMetadata = false);
 
   /// Read the header of the specified bitcode buffer and extract just the
   /// triple information. If successful, this returns a string. On error, this
   /// returns "".
   Expected<std::string> getBitcodeTargetTriple(MemoryBufferRef Buffer);
 
   /// Return true if \p Buffer contains a bitcode file with ObjC code (category
   /// or class) in it.
   Expected<bool> isBitcodeContainingObjCCategory(MemoryBufferRef Buffer);
 
   /// Read the header of the specified bitcode buffer and extract just the
   /// producer string information. If successful, this returns a string. On
   /// error, this returns "".
   Expected<std::string> getBitcodeProducerString(MemoryBufferRef Buffer);
 
   /// Read the specified bitcode file, returning the module.
-  ErrorOr<std::unique_ptr<Module>> parseBitcodeFile(MemoryBufferRef Buffer,
+  Expected<std::unique_ptr<Module>> parseBitcodeFile(MemoryBufferRef Buffer,
                                                      LLVMContext &Context);
 
   /// Check if the given bitcode buffer contains a summary block.
   Expected<bool> hasGlobalValueSummary(MemoryBufferRef Buffer);
 
   /// Parse the specified bitcode buffer, returning the module summary index.
   Expected<std::unique_ptr<ModuleSummaryIndex>>
   getModuleSummaryIndex(MemoryBufferRef Buffer);
 

llvm/include/llvm/Object/IRObjectFile.h

static void CollectAsmUndefinedRefs(
       function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmUndefinedRefs);
 
   /// \brief Finds and returns bitcode in the given memory buffer (which may
   /// be either a bitcode file or a native object file with embedded bitcode),
   /// or an error code if not found.
   static ErrorOr<MemoryBufferRef>
   findBitcodeInMemBuffer(MemoryBufferRef Object);
 
-  static ErrorOr<std::unique_ptr<IRObjectFile>> create(MemoryBufferRef Object,
+  static Expected<std::unique_ptr<IRObjectFile>> create(MemoryBufferRef Object,
                                                         LLVMContext &Context);
 };
 }
 }
 
 #endif

llvm/include/llvm/Transforms/IPO/FunctionImport.h

public:
   /// The map contains an entry for every module to import from, the key being
   /// the module identifier to pass to the ModuleLoader. The value is the set of
   /// functions to import.
   typedef StringMap<FunctionsToImportTy> ImportMapTy;
 
   /// The set contains an entry for every global value the module exports.
   typedef std::unordered_set<GlobalValue::GUID> ExportSetTy;
 
+  /// A function of this type is used to load modules referenced by the index.
+  typedef std::function<Expected<std::unique_ptr<Module>>(StringRef Identifier)>
+      ModuleLoaderTy;
+
   /// Create a Function Importer.
-  FunctionImporter(
-      const ModuleSummaryIndex &Index,
-      std::function<std::unique_ptr<Module>(StringRef Identifier)> ModuleLoader)
+  FunctionImporter(const ModuleSummaryIndex &Index, ModuleLoaderTy ModuleLoader)
       : Index(Index), ModuleLoader(std::move(ModuleLoader)) {}
 
   /// Import functions in Module \p M based on the supplied import list.
   /// \p ForceImportReferencedDiscardableSymbols will set the ModuleLinker in
   /// a mode where referenced discarable symbols in the source modules will be
   /// imported as well even if they are not present in the ImportList.
   Expected<bool>
   importFunctions(Module &M, const ImportMapTy &ImportList,
                   bool ForceImportReferencedDiscardableSymbols = false);
 
 private:
   /// The summaries index used to trigger importing.
   const ModuleSummaryIndex &Index;
 
   /// Factory function to load a Module for a given identifier
-  std::function<std::unique_ptr<Module>(StringRef Identifier)> ModuleLoader;
+  ModuleLoaderTy ModuleLoader;
 };
 
 /// The function importing pass
 class FunctionImportPass : public PassInfoMixin<FunctionImportPass> {
 public:
   FunctionImportPass(const ModuleSummaryIndex *Index = nullptr)
       : Index(Index) {}
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);

llvm/lib/Bitcode/Reader/BitReader.cpp

return LLVMParseBitcodeInContext(LLVMGetGlobalContext(), MemBuf, OutModule,
                                    OutMessage);
 }
 
 LLVMBool LLVMParseBitcode2(LLVMMemoryBufferRef MemBuf,
                            LLVMModuleRef *OutModule) {
   return LLVMParseBitcodeInContext2(LLVMGetGlobalContext(), MemBuf, OutModule);
 }
 
-static void diagnosticHandler(const DiagnosticInfo &DI, void *C) {
-  auto *Message = reinterpret_cast<std::string *>(C);
-  raw_string_ostream Stream(*Message);
-  DiagnosticPrinterRawOStream DP(Stream);
-  DI.print(DP);
-}
-
 LLVMBool LLVMParseBitcodeInContext(LLVMContextRef ContextRef,
                                    LLVMMemoryBufferRef MemBuf,
                                    LLVMModuleRef *OutModule,
                                    char **OutMessage) {
   MemoryBufferRef Buf = unwrap(MemBuf)->getMemBufferRef();
   LLVMContext &Ctx = *unwrap(ContextRef);
 
-  LLVMContext::DiagnosticHandlerTy OldDiagnosticHandler =
-      Ctx.getDiagnosticHandler();
-  void *OldDiagnosticContext = Ctx.getDiagnosticContext();
+  Expected<std::unique_ptr<Module>> ModuleOrErr = parseBitcodeFile(Buf, Ctx);
+  if (Error Err = ModuleOrErr.takeError()) {
     std::string Message;
-  Ctx.setDiagnosticHandler(diagnosticHandler, &Message, true);
-
-  ErrorOr<std::unique_ptr<Module>> ModuleOrErr = parseBitcodeFile(Buf, Ctx);
-
-  Ctx.setDiagnosticHandler(OldDiagnosticHandler, OldDiagnosticContext, true);
-
-  if (ModuleOrErr.getError()) {
+    handleAllErrors(std::move(Err), [&](ErrorInfoBase &EIB) {
+      Message = EIB.message();
+    });
     if (OutMessage)
       *OutMessage = strdup(Message.c_str());
     *OutModule = wrap((Module *)nullptr);
     return 1;
   }
 
   *OutModule = wrap(ModuleOrErr.get().release());
   return 0;
 }
 
 LLVMBool LLVMParseBitcodeInContext2(LLVMContextRef ContextRef,
                                     LLVMMemoryBufferRef MemBuf,
                                     LLVMModuleRef *OutModule) {
   MemoryBufferRef Buf = unwrap(MemBuf)->getMemBufferRef();
   LLVMContext &Ctx = *unwrap(ContextRef);
 
-  ErrorOr<std::unique_ptr<Module>> ModuleOrErr = parseBitcodeFile(Buf, Ctx);
+  ErrorOr<std::unique_ptr<Module>> ModuleOrErr =
+      expectedToErrorOrAndEmitErrors(Ctx, parseBitcodeFile(Buf, Ctx));
   if (ModuleOrErr.getError()) {
     *OutModule = wrap((Module *)nullptr);
     return 1;
   }
 
   *OutModule = wrap(ModuleOrErr.get().release());
   return 0;
 }
 
 /* Reads a module from the specified path, returning via the OutModule parameter
    a module provider which performs lazy deserialization. Returns 0 on success.
    Optionally returns a human-readable error message via OutMessage. */
 LLVMBool LLVMGetBitcodeModuleInContext(LLVMContextRef ContextRef,
                                        LLVMMemoryBufferRef MemBuf,
                                        LLVMModuleRef *OutM, char **OutMessage) {
   LLVMContext &Ctx = *unwrap(ContextRef);
-  LLVMContext::DiagnosticHandlerTy OldDiagnosticHandler =
-      Ctx.getDiagnosticHandler();
-  void *OldDiagnosticContext = Ctx.getDiagnosticContext();
-
-  std::string Message;
-  Ctx.setDiagnosticHandler(diagnosticHandler, &Message, true);
   std::unique_ptr<MemoryBuffer> Owner(unwrap(MemBuf));
-
-  ErrorOr<std::unique_ptr<Module>> ModuleOrErr =
+  Expected<std::unique_ptr<Module>> ModuleOrErr =
       getOwningLazyBitcodeModule(std::move(Owner), Ctx);
   Owner.release();
-  Ctx.setDiagnosticHandler(OldDiagnosticHandler, OldDiagnosticContext, true);
 
-  if (ModuleOrErr.getError()) {
-    *OutM = wrap((Module *)nullptr);
+  if (Error Err = ModuleOrErr.takeError()) {
+    std::string Message;
+    handleAllErrors(std::move(Err), [&](ErrorInfoBase &EIB) {
+      Message = EIB.message();
+    });
     if (OutMessage)
       *OutMessage = strdup(Message.c_str());
+    *OutM = wrap((Module *)nullptr);
     return 1;
   }
 
   *OutM = wrap(ModuleOrErr.get().release());
 
   return 0;
 }
 
 LLVMBool LLVMGetBitcodeModuleInContext2(LLVMContextRef ContextRef,
                                         LLVMMemoryBufferRef MemBuf,
                                         LLVMModuleRef *OutM) {
   LLVMContext &Ctx = *unwrap(ContextRef);
   std::unique_ptr<MemoryBuffer> Owner(unwrap(MemBuf));
 
-  ErrorOr<std::unique_ptr<Module>> ModuleOrErr =
-      getOwningLazyBitcodeModule(std::move(Owner), Ctx);
+  ErrorOr<std::unique_ptr<Module>> ModuleOrErr = expectedToErrorOrAndEmitErrors(
+      Ctx, getOwningLazyBitcodeModule(std::move(Owner), Ctx));
   Owner.release();
 
   if (ModuleOrErr.getError()) {
     *OutM = wrap((Module *)nullptr);
     return 1;
   }
 
   *OutM = wrap(ModuleOrErr.get().release());

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

 /// \brief Get a lazy one-at-time loading module from bitcode.
 ///
 /// This isn't always used in a lazy context.  In particular, it's also used by
 /// \a parseBitcodeFile().  If this is truly lazy, then we need to eagerly pull
 /// in forward-referenced functions from block address references.
 ///
 /// \param[in] MaterializeAll Set to \c true if we should materialize
 /// everything.
-static ErrorOr<std::unique_ptr<Module>>
+static Expected<std::unique_ptr<Module>>
 getLazyBitcodeModuleImpl(MemoryBufferRef Buffer, LLVMContext &Context,
                          bool MaterializeAll,
                          bool ShouldLazyLoadMetadata = false) {
   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
   if (!StreamOrErr)
-    return errorToErrorCodeAndEmitErrors(Context, StreamOrErr.takeError());
+    return StreamOrErr.takeError();
 
   BitcodeReader *R = new BitcodeReader(std::move(*StreamOrErr), Context);
 
   std::unique_ptr<Module> M =
       llvm::make_unique<Module>(Buffer.getBufferIdentifier(), Context);
   M->setMaterializer(R);
 
   // Delay parsing Metadata if ShouldLazyLoadMetadata is true.
   if (Error Err = R->parseBitcodeInto(M.get(), ShouldLazyLoadMetadata))
-    return errorToErrorCodeAndEmitErrors(Context, std::move(Err));
+    return std::move(Err);
 
   if (MaterializeAll) {
     // Read in the entire module, and destroy the BitcodeReader.
     if (Error Err = M->materializeAll())
-      return errorToErrorCodeAndEmitErrors(Context, std::move(Err));
+      return std::move(Err);
   } else {
     // Resolve forward references from blockaddresses.
     if (Error Err = R->materializeForwardReferencedFunctions())
-      return errorToErrorCodeAndEmitErrors(Context, std::move(Err));
+      return std::move(Err);
   }
   return std::move(M);
 }
 
-ErrorOr<std::unique_ptr<Module>>
+Expected<std::unique_ptr<Module>>
 llvm::getLazyBitcodeModule(MemoryBufferRef Buffer,
                            LLVMContext &Context, bool ShouldLazyLoadMetadata) {
   return getLazyBitcodeModuleImpl(Buffer, Context, false,
                                   ShouldLazyLoadMetadata);
 }
 
-ErrorOr<std::unique_ptr<Module>>
+Expected<std::unique_ptr<Module>>
 llvm::getOwningLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
                                  LLVMContext &Context,
                                  bool ShouldLazyLoadMetadata) {
   auto MOrErr = getLazyBitcodeModule(*Buffer, Context, ShouldLazyLoadMetadata);
   if (MOrErr)
     (*MOrErr)->setOwnedMemoryBuffer(std::move(Buffer));
   return MOrErr;
 }
 
-ErrorOr<std::unique_ptr<Module>> llvm::parseBitcodeFile(MemoryBufferRef Buffer,
+Expected<std::unique_ptr<Module>> llvm::parseBitcodeFile(MemoryBufferRef Buffer,
                                                          LLVMContext &Context) {
   return getLazyBitcodeModuleImpl(Buffer, Context, true);
   // TODO: Restore the use-lists to the in-memory state when the bitcode was
   // written.  We must defer until the Module has been fully materialized.
 }
 
 Expected<std::string> llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer) {
   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
   if (!StreamOrErr)

llvm/lib/CodeGen/ParallelCG.cpp

SplitModule(
             BCOSs[ThreadCount]->flush();
           }
 
           llvm::raw_pwrite_stream *ThreadOS = OSs[ThreadCount++];
           // Enqueue the task
           CodegenThreadPool.async(
               [TMFactory, FileType, ThreadOS](const SmallString<0> &BC) {
                 LLVMContext Ctx;
-                ErrorOr<std::unique_ptr<Module>> MOrErr = parseBitcodeFile(
+                Expected<std::unique_ptr<Module>> MOrErr = parseBitcodeFile(
                     MemoryBufferRef(StringRef(BC.data(), BC.size()),
                                     "<split-module>"),
                     Ctx);
                 if (!MOrErr)
                   report_fatal_error("Failed to read bitcode");
                 std::unique_ptr<Module> MPartInCtx = std::move(MOrErr.get());
 
                 codegen(MPartInCtx.get(), *ThreadOS, TMFactory, FileType);

llvm/lib/IRReader/IRReader.cpp

 static const char *const TimeIRParsingGroupName = "LLVM IR Parsing";
 static const char *const TimeIRParsingName = "Parse IR";
 
 static std::unique_ptr<Module>
 getLazyIRModule(std::unique_ptr<MemoryBuffer> Buffer, SMDiagnostic &Err,
                 LLVMContext &Context, bool ShouldLazyLoadMetadata) {
   if (isBitcode((const unsigned char *)Buffer->getBufferStart(),
                 (const unsigned char *)Buffer->getBufferEnd())) {
-    ErrorOr<std::unique_ptr<Module>> ModuleOrErr = getOwningLazyBitcodeModule(
+    Expected<std::unique_ptr<Module>> ModuleOrErr = getOwningLazyBitcodeModule(
         std::move(Buffer), Context, ShouldLazyLoadMetadata);
-    if (std::error_code EC = ModuleOrErr.getError()) {
+    if (Error E = ModuleOrErr.takeError()) {
+      handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
         Err = SMDiagnostic(Buffer->getBufferIdentifier(), SourceMgr::DK_Error,
-                         EC.message());
+                           EIB.message());
+      });
       return nullptr;
     }
     return std::move(ModuleOrErr.get());
   }
 
   return parseAssembly(Buffer->getMemBufferRef(), Err, Context);
 }
 

 }
 
 std::unique_ptr<Module> llvm::parseIR(MemoryBufferRef Buffer, SMDiagnostic &Err,
                                       LLVMContext &Context) {
   NamedRegionTimer T(TimeIRParsingName, TimeIRParsingGroupName,
                      TimePassesIsEnabled);
   if (isBitcode((const unsigned char *)Buffer.getBufferStart(),
                 (const unsigned char *)Buffer.getBufferEnd())) {
-    ErrorOr<std::unique_ptr<Module>> ModuleOrErr =
+    Expected<std::unique_ptr<Module>> ModuleOrErr =
         parseBitcodeFile(Buffer, Context);
-    if (std::error_code EC = ModuleOrErr.getError()) {
+    if (Error E = ModuleOrErr.takeError()) {
+      handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
         Err = SMDiagnostic(Buffer.getBufferIdentifier(), SourceMgr::DK_Error,
-                         EC.message());
+                           EIB.message());
+      });
       return nullptr;
     }
     return std::move(ModuleOrErr.get());
   }
 
   return parseAssembly(Buffer, Err, Context);
 }
 

llvm/lib/LTO/LTO.cpp

#endif
   Key = toHex(Hasher.result());
 }
 
 // Simple helper to load a module from bitcode
 std::unique_ptr<Module>
 llvm::loadModuleFromBuffer(const MemoryBufferRef &Buffer, LLVMContext &Context,
                            bool Lazy) {
   SMDiagnostic Err;
-  ErrorOr<std::unique_ptr<Module>> ModuleOrErr(nullptr);
-  if (Lazy) {
-    ModuleOrErr = getLazyBitcodeModule(Buffer, Context,
-                                       /* ShouldLazyLoadMetadata */ Lazy);
-  } else {
-    ModuleOrErr = parseBitcodeFile(Buffer, Context);
-  }
-  if (std::error_code EC = ModuleOrErr.getError()) {
-    Err = SMDiagnostic(Buffer.getBufferIdentifier(), SourceMgr::DK_Error,
-                       EC.message());
+  Expected<std::unique_ptr<Module>> ModuleOrErr =
+      Lazy ? getLazyBitcodeModule(Buffer, Context,
+                                  /* ShouldLazyLoadMetadata */ true)
+           : parseBitcodeFile(Buffer, Context);
+  if (!ModuleOrErr) {
+    handleAllErrors(ModuleOrErr.takeError(), [&](ErrorInfoBase &EIB) {
+      SMDiagnostic Err = SMDiagnostic(Buffer.getBufferIdentifier(),
+                                      SourceMgr::DK_Error, EIB.message());
       Err.print("ThinLTO", errs());
+    });
     report_fatal_error("Can't load module, abort.");
   }
   return std::move(ModuleOrErr.get());
 }
 
 static void thinLTOResolveWeakForLinkerGUID(
     GlobalValueSummaryList &GVSummaryList, GlobalValue::GUID GUID,
     DenseSet<GlobalValueSummary *> &GlobalInvolvedWithAlias,
void llvm::thinLTOInternalizeAndPromoteInIndex(
     ModuleSummaryIndex &Index,
     function_ref<bool(StringRef, GlobalValue::GUID)> isExported) {
   for (auto &I : Index)
     thinLTOInternalizeAndPromoteGUID(I.second, I.first, isExported);
 }
 
 Expected<std::unique_ptr<InputFile>> InputFile::create(MemoryBufferRef Object) {
   std::unique_ptr<InputFile> File(new InputFile);
-  std::string Msg;
-  auto DiagHandler = [](const DiagnosticInfo &DI, void *MsgP) {
-    auto *Msg = reinterpret_cast<std::string *>(MsgP);
-    raw_string_ostream OS(*Msg);
-    DiagnosticPrinterRawOStream DP(OS);
-    DI.print(DP);
-  };
-  File->Ctx.setDiagnosticHandler(DiagHandler, static_cast<void *>(&Msg));
 
-  ErrorOr<std::unique_ptr<object::IRObjectFile>> IRObj =
+  Expected<std::unique_ptr<object::IRObjectFile>> IRObj =
       IRObjectFile::create(Object, File->Ctx);
-  if (!Msg.empty())
-    return make_error<StringError>(Msg, inconvertibleErrorCode());
   if (!IRObj)
-    return errorCodeToError(IRObj.getError());
+    return IRObj.takeError();
   File->Obj = std::move(*IRObj);
 
-  File->Ctx.setDiagnosticHandler(nullptr, nullptr);
-
   for (const auto &C : File->Obj->getModule().getComdatSymbolTable()) {
     auto P =
         File->ComdatMap.insert(std::make_pair(&C.second, File->Comdats.size()));
     assert(P.second);
     (void)P;
     File->Comdats.push_back(C.first());
   }
 

 // Add a regular LTO object to the link.
 Error LTO::addRegularLTO(std::unique_ptr<InputFile> Input,
                          ArrayRef<SymbolResolution> Res) {
   if (!RegularLTO.CombinedModule) {
     RegularLTO.CombinedModule =
         llvm::make_unique<Module>("ld-temp.o", RegularLTO.Ctx);
     RegularLTO.Mover = llvm::make_unique<IRMover>(*RegularLTO.CombinedModule);
   }
-  ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
+  Expected<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
       IRObjectFile::create(Input->Obj->getMemoryBufferRef(), RegularLTO.Ctx);
   if (!ObjOrErr)
-    return errorCodeToError(ObjOrErr.getError());
+    return ObjOrErr.takeError();
   std::unique_ptr<object::IRObjectFile> Obj = std::move(*ObjOrErr);
 
   Module &M = Obj->getModule();
   if (Error Err = M.materializeMetadata())
     return Err;
   UpgradeDebugInfo(M);
 
   SmallPtrSet<GlobalValue *, 8> Used;
Error runThinLTOBackendThread(
       MemoryBufferRef MBRef, ModuleSummaryIndex &CombinedIndex,
       const FunctionImporter::ImportMapTy &ImportList,
       const FunctionImporter::ExportSetTy &ExportList,
       const std::map<GlobalValue::GUID, GlobalValue::LinkageTypes> &ResolvedODR,
       const GVSummaryMapTy &DefinedGlobals,
       MapVector<StringRef, MemoryBufferRef> &ModuleMap) {
     auto RunThinBackend = [&](AddStreamFn AddStream) {
       LTOLLVMContext BackendContext(Conf);
-      ErrorOr<std::unique_ptr<Module>> MOrErr =
+      Expected<std::unique_ptr<Module>> MOrErr =
           parseBitcodeFile(MBRef, BackendContext);
-      assert(MOrErr && "Unable to load module in thread?");
+      if (!MOrErr)
+        return MOrErr.takeError();
 
       return thinBackend(Conf, Task, AddStream, **MOrErr, CombinedIndex,
                          ImportList, DefinedGlobals, ModuleMap);
     };
 
     auto ModuleID = MBRef.getBufferIdentifier();
 
     if (!Cache || !CombinedIndex.modulePaths().count(ModuleID) ||

llvm/lib/LTO/LTOBackend.cpp

SplitModule(
         SmallString<0> BC;
         raw_svector_ostream BCOS(BC);
         WriteBitcodeToFile(MPart.get(), BCOS);
 
         // Enqueue the task
         CodegenThreadPool.async(
             [&](const SmallString<0> &BC, unsigned ThreadId) {
               LTOLLVMContext Ctx(C);
-              ErrorOr<std::unique_ptr<Module>> MOrErr = parseBitcodeFile(
+              Expected<std::unique_ptr<Module>> MOrErr = parseBitcodeFile(
                   MemoryBufferRef(StringRef(BC.data(), BC.size()), "ld-temp.o"),
                   Ctx);
               if (!MOrErr)
                 report_fatal_error("Failed to read bitcode");
               std::unique_ptr<Module> MPartInCtx = std::move(MOrErr.get());
 
               std::unique_ptr<TargetMachine> TM =
                   createTargetMachine(C, MPartInCtx->getTargetTriple(), T);
Error lto::thinBackend(Config &Conf, unsigned Task, AddStreamFn AddStream,
 
   if (Conf.PostInternalizeModuleHook &&
       !Conf.PostInternalizeModuleHook(Task, Mod))
     return Error::success();
 
   auto ModuleLoader = [&](StringRef Identifier) {
     assert(Mod.getContext().isODRUniquingDebugTypes() &&
            "ODR Type uniquing should be enabled on the context");
-    return std::move(getLazyBitcodeModule(ModuleMap[Identifier],
-                                          Mod.getContext(),
-                                          /*ShouldLazyLoadMetadata=*/true)
-                         .get());
+    return getLazyBitcodeModule(ModuleMap[Identifier], Mod.getContext(),
+                                /*ShouldLazyLoadMetadata=*/true);
   };
 
   FunctionImporter Importer(CombinedIndex, ModuleLoader);
   if (Error Err = Importer.importFunctions(Mod, ImportList).takeError())
     return Err;
 
   if (Conf.PostImportModuleHook && !Conf.PostImportModuleHook(Task, Mod))
     return Error::success();
 
   if (!opt(Conf, TM.get(), Task, Mod, /*IsThinLto=*/true))
     return Error::success();
 
   codegen(Conf, TM.get(), AddStream, Task, Mod);
   return Error::success();
 }

llvm/lib/LTO/LTOModule.cpp

ErrorOr<MemoryBufferRef> MBOrErr =
       IRObjectFile::findBitcodeInMemBuffer(Buffer);
   if (std::error_code EC = MBOrErr.getError()) {
     Context.emitError(EC.message());
     return EC;
   }
 
   if (!ShouldBeLazy) {
     // Parse the full file.
-    ErrorOr<std::unique_ptr<Module>> M = parseBitcodeFile(*MBOrErr, Context);
-    if (std::error_code EC = M.getError())
-      return EC;
-    return std::move(*M);
+    return expectedToErrorOrAndEmitErrors(Context,
+                                          parseBitcodeFile(*MBOrErr, Context));
   }
 
   // Parse lazily.
-  ErrorOr<std::unique_ptr<Module>> M =
-      getLazyBitcodeModule(*MBOrErr, Context, true /*ShouldLazyLoadMetadata*/);
-  if (std::error_code EC = M.getError())
-    return EC;
-  return std::move(*M);
+  return expectedToErrorOrAndEmitErrors(
+      Context,
+      getLazyBitcodeModule(*MBOrErr, Context, true /*ShouldLazyLoadMetadata*/));
 }
 
 ErrorOr<std::unique_ptr<LTOModule>>
 LTOModule::makeLTOModule(MemoryBufferRef Buffer, const TargetOptions &options,
                          LLVMContext &Context, bool ShouldBeLazy) {
   ErrorOr<std::unique_ptr<Module>> MOrErr =
       parseBitcodeFileImpl(Buffer, Context, ShouldBeLazy);
   if (std::error_code EC = MOrErr.getError())

llvm/lib/Object/IRObjectFile.cpp

if (!ObjFile)
       return errorToErrorCode(ObjFile.takeError());
     return findBitcodeInObject(*ObjFile->get());
   }
   default:
     return object_error::invalid_file_type;
   }
 }
 
-ErrorOr<std::unique_ptr<IRObjectFile>>
+Expected<std::unique_ptr<IRObjectFile>>
 llvm::object::IRObjectFile::create(MemoryBufferRef Object,
                                    LLVMContext &Context) {
   ErrorOr<MemoryBufferRef> BCOrErr = findBitcodeInMemBuffer(Object);
   if (!BCOrErr)
-    return BCOrErr.getError();
+    return errorCodeToError(BCOrErr.getError());
 
-  ErrorOr<std::unique_ptr<Module>> MOrErr =
+  Expected<std::unique_ptr<Module>> MOrErr =
       getLazyBitcodeModule(*BCOrErr, Context,
                            /*ShouldLazyLoadMetadata*/ true);
-  if (std::error_code EC = MOrErr.getError())
-    return EC;
+  if (!MOrErr)
+    return MOrErr.takeError();
 
   std::unique_ptr<Module> &M = MOrErr.get();
   return llvm::make_unique<IRObjectFile>(BCOrErr.get(), std::move(M));
 }

llvm/lib/Object/SymbolicFile.cpp

Expected<std::unique_ptr<SymbolicFile>> SymbolicFile::createSymbolicFile(
     MemoryBufferRef Object, sys::fs::file_magic Type, LLVMContext *Context) {
   StringRef Data = Object.getBuffer();
   if (Type == sys::fs::file_magic::unknown)
     Type = sys::fs::identify_magic(Data);
 
   switch (Type) {
   case sys::fs::file_magic::bitcode:
     if (Context)
-      return errorOrToExpected(IRObjectFile::create(Object, *Context));
+      return IRObjectFile::create(Object, *Context);
     LLVM_FALLTHROUGH;
   case sys::fs::file_magic::unknown:
   case sys::fs::file_magic::archive:
   case sys::fs::file_magic::macho_universal_binary:
   case sys::fs::file_magic::windows_resource:
     return errorCodeToError(object_error::invalid_file_type);
   case sys::fs::file_magic::elf:
   case sys::fs::file_magic::elf_executable:
case sys::fs::file_magic::coff_object: {
     if (!Obj || !Context)
       return std::move(Obj);
 
     ErrorOr<MemoryBufferRef> BCData =
         IRObjectFile::findBitcodeInObject(*Obj->get());
     if (!BCData)
       return std::move(Obj);
 
-    return errorOrToExpected(IRObjectFile::create(
-                                 MemoryBufferRef(BCData->getBuffer(),
-                                 Object.getBufferIdentifier()), *Context));
+    return IRObjectFile::create(
+        MemoryBufferRef(BCData->getBuffer(), Object.getBufferIdentifier()),
+        *Context);
   }
   }
   llvm_unreachable("Unexpected Binary File Type");
 }

llvm/lib/Transforms/IPO/FunctionImport.cpp

Expected<bool> FunctionImporter::importFunctions(
   std::set<StringRef> ModuleNameOrderedList;
   for (auto &FunctionsToImportPerModule : ImportList) {
     ModuleNameOrderedList.insert(FunctionsToImportPerModule.first());
   }
   for (auto &Name : ModuleNameOrderedList) {
     // Get the module for the import
     const auto &FunctionsToImportPerModule = ImportList.find(Name);
     assert(FunctionsToImportPerModule != ImportList.end());
-    std::unique_ptr<Module> SrcModule = ModuleLoader(Name);
+    Expected<std::unique_ptr<Module>> SrcModuleOrErr = ModuleLoader(Name);
+    if (!SrcModuleOrErr)
+      return SrcModuleOrErr.takeError();
+    std::unique_ptr<Module> SrcModule = std::move(*SrcModuleOrErr);
     assert(&DestModule.getContext() == &SrcModule->getContext() &&
            "Context mismatch");
 
     // If modules were created with lazy metadata loading, materialize it
     // now, before linking it (otherwise this will be a noop).
     if (Error Err = SrcModule->materializeMetadata())
       return std::move(Err);
     UpgradeDebugInfo(*SrcModule);

llvm/tools/llvm-dis/llvm-dis.cpp

if (DI.getSeverity() == DS_Error)
     exit(1);
 }
 
 static ExitOnError ExitOnErr;
 
 static std::unique_ptr<Module> openInputFile(LLVMContext &Context) {
   std::unique_ptr<MemoryBuffer> MB =
       ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
-  std::unique_ptr<Module> M = ExitOnErr(errorOrToExpected(
-      getOwningLazyBitcodeModule(std::move(MB), Context,
-                                 /*ShouldLazyLoadMetadata=*/true)));
+  std::unique_ptr<Module> M =
+      ExitOnErr(getOwningLazyBitcodeModule(std::move(MB), Context,
+                                           /*ShouldLazyLoadMetadata=*/true));
   if (MaterializeMetadata)
     ExitOnErr(M->materializeMetadata());
   else
     ExitOnErr(M->materializeAll());
   return M;
 }
 
 int main(int argc, char **argv) {

llvm/tools/verify-uselistorder/verify-uselistorder.cpp

ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOr =
       MemoryBuffer::getFile(Filename);
   if (!BufferOr) {
     errs() << "verify-uselistorder: error: " << BufferOr.getError().message()
            << "\n";
     return nullptr;
   }
 
   MemoryBuffer *Buffer = BufferOr.get().get();
-  ErrorOr<std::unique_ptr<Module>> ModuleOr =
+  Expected<std::unique_ptr<Module>> ModuleOr =
       parseBitcodeFile(Buffer->getMemBufferRef(), Context);
   if (!ModuleOr) {
-    errs() << "verify-uselistorder: error: " << ModuleOr.getError().message()
-           << "\n";
+    logAllUnhandledErrors(ModuleOr.takeError(), errs(),
+                          "verify-uselistorder: error: ");
     return nullptr;
   }
   return std::move(ModuleOr.get());
 }
 
 std::unique_ptr<Module> TempFile::readAssembly(LLVMContext &Context) const {
   DEBUG(dbgs() << " - read assembly\n");
   SMDiagnostic Err;

llvm/unittests/Bitcode/BitReaderTest.cpp

static void writeModuleToBuffer(std::unique_ptr<Module> Mod,
   raw_svector_ostream OS(Buffer);
   WriteBitcodeToFile(Mod.get(), OS);
 }
 
 static std::unique_ptr<Module> getLazyModuleFromAssembly(LLVMContext &Context,
                                                          SmallString<1024> &Mem,
                                                          const char *Assembly) {
   writeModuleToBuffer(parseAssembly(Context, Assembly), Mem);
-  ErrorOr<std::unique_ptr<Module>> ModuleOrErr =
+  Expected<std::unique_ptr<Module>> ModuleOrErr =
       getLazyBitcodeModule(MemoryBufferRef(Mem.str(), "test"), Context);
+  if (!ModuleOrErr)
+    report_fatal_error("Could not parse bitcode module");
   return std::move(ModuleOrErr.get());
 }
 
 // Tests that lazy evaluation can parse functions out of order.
 TEST(BitReaderTest, MaterializeFunctionsOutOfOrder) {
   SmallString<1024> Mem;
   LLVMContext Context;
   std::unique_ptr<Module> M = getLazyModuleFromAssembly(