[llvm-objcopy][NFC] refactor error handling. part 3.

Remove usages of special error reporting functions(error(),
reportError()). Errors are reported as Expected<>/Error returning
values. This part is for ELF subfolder of llvm-objcopy.

Testing: check-all.

Differential Revision: https://reviews.llvm.org/D87987

Author: avl-llvm

llvm/tools/llvm-objcopy/COFF/COFFObjcopy.cpp

@@ -12,7 +12,6 @@
 #include "Object.h"
 #include "Reader.h"
 #include "Writer.h"
-#include "llvm-objcopy.h"
 
 #include "llvm/Object/Binary.h"
 #include "llvm/Object/COFF.h"

llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp

@@ -10,7 +10,6 @@
 #include "Buffer.h"
 #include "CopyConfig.h"
 #include "Object.h"
-#include "llvm-objcopy.h"
 #include "llvm/ADT/BitmaskEnum.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/Optional.h"
@@ -266,19 +265,23 @@ static Error linkToBuildIdDir(const CopyConfig &Config, StringRef ToLink,
 
 static Error splitDWOToFile(const CopyConfig &Config, const Reader &Reader,
                             StringRef File, ElfType OutputElfType) {
-  auto DWOFile = Reader.create(false);
+  Expected<std::unique_ptr<Object>> DWOFile = Reader.create(false);
+  if (!DWOFile)
+    return DWOFile.takeError();
+
   auto OnlyKeepDWOPred = [&DWOFile](const SectionBase &Sec) {
-    return onlyKeepDWOPred(*DWOFile, Sec);
+    return onlyKeepDWOPred(**DWOFile, Sec);
   };
-  if (Error E = DWOFile->removeSections(Config.AllowBrokenLinks,
-                                        OnlyKeepDWOPred))
+  if (Error E =
+          (*DWOFile)->removeSections(Config.AllowBrokenLinks, OnlyKeepDWOPred))
     return E;
   if (Config.OutputArch) {
-    DWOFile->Machine = Config.OutputArch.getValue().EMachine;
-    DWOFile->OSABI = Config.OutputArch.getValue().OSABI;
+    (*DWOFile)->Machine = Config.OutputArch.getValue().EMachine;
+    (*DWOFile)->OSABI = Config.OutputArch.getValue().OSABI;
   }
   FileBuffer FB(File);
-  auto Writer = createWriter(Config, *DWOFile, FB, OutputElfType);
+  std::unique_ptr<Writer> Writer =
+      createWriter(Config, **DWOFile, FB, OutputElfType);
   if (Error E = Writer->finalize())
     return E;
   return Writer->write();
@@ -313,12 +316,12 @@ static bool isCompressable(const SectionBase &Sec) {
          StringRef(Sec.Name).startswith(".debug");
 }
 
-static void replaceDebugSections(
+static Error replaceDebugSections(
     Object &Obj, SectionPred &RemovePred,
     function_ref<bool(const SectionBase &)> shouldReplace,
-    function_ref<SectionBase *(const SectionBase *)> addSection) {
+    function_ref<Expected<SectionBase *>(const SectionBase *)> addSection) {
   // Build a list of the debug sections we are going to replace.
-  // We can't call `addSection` while iterating over sections,
+  // We can't call `AddSection` while iterating over sections,
   // because it would mutate the sections array.
   SmallVector<SectionBase *, 13> ToReplace;
   for (auto &Sec : Obj.sections())
@@ -327,8 +330,13 @@ static void replaceDebugSections(
 
   // Build a mapping from original section to a new one.
   DenseMap<SectionBase *, SectionBase *> FromTo;
-  for (SectionBase *S : ToReplace)
-    FromTo[S] = addSection(S);
+  for (SectionBase *S : ToReplace) {
+    Expected<SectionBase *> NewSection = addSection(S);
+    if (!NewSection)
+      return NewSection.takeError();
+
+    FromTo[S] = *NewSection;
+  }
 
   // Now we want to update the target sections of relocation
   // sections. Also we will update the relocations themselves
@@ -339,6 +347,8 @@ static void replaceDebugSections(
   RemovePred = [shouldReplace, RemovePred](const SectionBase &Sec) {
     return shouldReplace(Sec) || RemovePred(Sec);
   };
+
+  return Error::success();
 }
 
 static bool isUnneededSymbol(const Symbol &Sym) {
@@ -577,20 +587,28 @@ static Error replaceAndRemoveSections(const CopyConfig &Config, Object &Obj) {
     };
   }
 
-  if (Config.CompressionType != DebugCompressionType::None)
-    replaceDebugSections(Obj, RemovePred, isCompressable,
-                         [&Config, &Obj](const SectionBase *S) {
-                           return &Obj.addSection<CompressedSection>(
-                                *S, Config.CompressionType);
-                         });
-  else if (Config.DecompressDebugSections)
-    replaceDebugSections(
-        Obj, RemovePred,
-        [](const SectionBase &S) { return isa<CompressedSection>(&S); },
-        [&Obj](const SectionBase *S) {
-          auto CS = cast<CompressedSection>(S);
-          return &Obj.addSection<DecompressedSection>(*CS);
-        });
+  if (Config.CompressionType != DebugCompressionType::None) {
+    if (Error Err = replaceDebugSections(
+            Obj, RemovePred, isCompressable,
+            [&Config, &Obj](const SectionBase *S) -> Expected<SectionBase *> {
+              Expected<CompressedSection> NewSection =
+                  CompressedSection::create(*S, Config.CompressionType);
+              if (!NewSection)
+                return NewSection.takeError();
+
+              return &Obj.addSection<CompressedSection>(std::move(*NewSection));
+            }))
+      return Err;
+  } else if (Config.DecompressDebugSections) {
+    if (Error Err = replaceDebugSections(
+            Obj, RemovePred,
+            [](const SectionBase &S) { return isa<CompressedSection>(&S); },
+            [&Obj](const SectionBase *S) {
+              const CompressedSection *CS = cast<CompressedSection>(S);
+              return &Obj.addSection<DecompressedSection>(*CS);
+            }))
+      return Err;
+  }
 
   return Obj.removeSections(Config.AllowBrokenLinks, RemovePred);
 }
@@ -740,9 +758,9 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj,
 
   // If the symbol table was previously removed, we need to create a new one
   // before adding new symbols.
-  if (!Obj.SymbolTable && !Config.ELF->SymbolsToAdd.empty()) {
-    Obj.addNewSymbolTable();
-  }
+  if (!Obj.SymbolTable && !Config.ELF->SymbolsToAdd.empty())
+    if (Error E = Obj.addNewSymbolTable())
+      return E;
 
   for (const NewSymbolInfo &SI : Config.ELF->SymbolsToAdd) {
     SectionBase *Sec = Obj.findSection(SI.SectionName);
@@ -769,34 +787,42 @@ static Error writeOutput(const CopyConfig &Config, Object &Obj, Buffer &Out,
 Error executeObjcopyOnIHex(const CopyConfig &Config, MemoryBuffer &In,
                            Buffer &Out) {
   IHexReader Reader(&In);
-  std::unique_ptr<Object> Obj = Reader.create(true);
+  Expected<std::unique_ptr<Object>> Obj = Reader.create(true);
+  if (!Obj)
+    return Obj.takeError();
+
   const ElfType OutputElfType =
     getOutputElfType(Config.OutputArch.getValueOr(MachineInfo()));
-  if (Error E = handleArgs(Config, *Obj, Reader, OutputElfType))
+  if (Error E = handleArgs(Config, **Obj, Reader, OutputElfType))
     return E;
-  return writeOutput(Config, *Obj, Out, OutputElfType);
+  return writeOutput(Config, **Obj, Out, OutputElfType);
 }
 
 Error executeObjcopyOnRawBinary(const CopyConfig &Config, MemoryBuffer &In,
                                 Buffer &Out) {
   uint8_t NewSymbolVisibility =
       Config.ELF->NewSymbolVisibility.getValueOr((uint8_t)ELF::STV_DEFAULT);
   BinaryReader Reader(&In, NewSymbolVisibility);
-  std::unique_ptr<Object> Obj = Reader.create(true);
+  Expected<std::unique_ptr<Object>> Obj = Reader.create(true);
+  if (!Obj)
+    return Obj.takeError();
 
   // Prefer OutputArch (-O<format>) if set, otherwise fallback to BinaryArch
   // (-B<arch>).
   const ElfType OutputElfType =
       getOutputElfType(Config.OutputArch.getValueOr(MachineInfo()));
-  if (Error E = handleArgs(Config, *Obj, Reader, OutputElfType))
+  if (Error E = handleArgs(Config, **Obj, Reader, OutputElfType))
     return E;
-  return writeOutput(Config, *Obj, Out, OutputElfType);
+  return writeOutput(Config, **Obj, Out, OutputElfType);
 }
 
 Error executeObjcopyOnBinary(const CopyConfig &Config,
                              object::ELFObjectFileBase &In, Buffer &Out) {
   ELFReader Reader(&In, Config.ExtractPartition);
-  std::unique_ptr<Object> Obj = Reader.create(!Config.SymbolsToAdd.empty());
+  Expected<std::unique_ptr<Object>> Obj =
+      Reader.create(!Config.SymbolsToAdd.empty());
+  if (!Obj)
+    return Obj.takeError();
   // Prefer OutputArch (-O<format>) if set, otherwise infer it from the input.
   const ElfType OutputElfType =
       Config.OutputArch ? getOutputElfType(Config.OutputArch.getValue())
@@ -822,10 +848,10 @@ Error executeObjcopyOnBinary(const CopyConfig &Config,
                              Config.BuildIdLinkInput.getValue(), BuildIdBytes))
       return E;
 
-  if (Error E = handleArgs(Config, *Obj, Reader, OutputElfType))
+  if (Error E = handleArgs(Config, **Obj, Reader, OutputElfType))
     return createFileError(Config.InputFilename, std::move(E));
 
-  if (Error E = writeOutput(Config, *Obj, Out, OutputElfType))
+  if (Error E = writeOutput(Config, **Obj, Out, OutputElfType))
     return createFileError(Config.InputFilename, std::move(E));
   if (!Config.BuildIdLinkDir.empty() && Config.BuildIdLinkOutput)
     if (Error E =