[llvm-objcopy][NFC] refactor error handling. part 2.

Remove usages of special error reporting functions(error(),
reportError()). This patch is extracted from D87987.
Errors are reported as Expected<>/Error returning values.
This part is for COFF subfolder of llvm-objcopy.

Testing: check-all.

Differential Revision: https://reviews.llvm.org/D88213

tools/llvm-objcopy/COFF/COFFObjcopy.cpp

@@ -40,11 +40,12 @@ static uint64_t getNextRVA(const Object &Obj) {
                  Obj.IsPE ? Obj.PeHeader.SectionAlignment : 1);
 }
 
-static std::vector<uint8_t> createGnuDebugLinkSectionContents(StringRef File) {
+static Expected<std::vector<uint8_t>>
+createGnuDebugLinkSectionContents(StringRef File) {
   ErrorOr<std::unique_ptr<MemoryBuffer>> LinkTargetOrErr =
       MemoryBuffer::getFile(File);
   if (!LinkTargetOrErr)
-    error("'" + File + "': " + LinkTargetOrErr.getError().message());
+    return createFileError(File, LinkTargetOrErr.getError());
   auto LinkTarget = std::move(*LinkTargetOrErr);
   uint32_t CRC32 = llvm::crc32(arrayRefFromStringRef(LinkTarget->getBuffer()));
 
@@ -81,12 +82,17 @@ static void addSection(Object &Obj, StringRef Name, ArrayRef<uint8_t> Contents,
   Obj.addSections(Sec);
 }
 
-static void addGnuDebugLink(Object &Obj, StringRef DebugLinkFile) {
-  std::vector<uint8_t> Contents =
+static Error addGnuDebugLink(Object &Obj, StringRef DebugLinkFile) {
+  Expected<std::vector<uint8_t>> Contents =
       createGnuDebugLinkSectionContents(DebugLinkFile);
-  addSection(Obj, ".gnu_debuglink", Contents,
+  if (!Contents)
+    return Contents.takeError();
+
+  addSection(Obj, ".gnu_debuglink", *Contents,
              IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ |
                  IMAGE_SCN_MEM_DISCARDABLE);
+
+  return Error::success();
 }
 
 static void setSectionFlags(Section &Sec, SectionFlag AllFlags) {
@@ -174,8 +180,7 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
       Sym.Name = I->getValue();
   }
 
-  // Actually do removals of symbols.
-  Obj.removeSymbols([&](const Symbol &Sym) {
+  auto ToRemove = [&](const Symbol &Sym) -> Expected<bool> {
     // For StripAll, all relocations have been stripped and we remove all
     // symbols.
     if (Config.StripAll || Config.StripAllGNU)
@@ -184,11 +189,10 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
     if (Config.SymbolsToRemove.matches(Sym.Name)) {
       // Explicitly removing a referenced symbol is an error.
       if (Sym.Referenced)
-        reportError(Config.OutputFilename,
-                    createStringError(llvm::errc::invalid_argument,
-                                      "not stripping symbol '%s' because it is "
-                                      "named in a relocation",
-                                      Sym.Name.str().c_str()));
+        return createStringError(
+            llvm::errc::invalid_argument,
+            "'" + Config.OutputFilename + "': not stripping symbol '" +
+                Sym.Name.str() + "' because it is named in a relocation");
       return true;
     }
 
@@ -213,7 +217,11 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
     }
 
     return false;
-  });
+  };
+
+  // Actually do removals of symbols.
+  if (Error Err = Obj.removeSymbols(ToRemove))
+    return Err;
 
   if (!Config.SetSectionFlags.empty())
     for (Section &Sec : Obj.getMutableSections()) {
@@ -239,7 +247,8 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
   }
 
   if (!Config.AddGnuDebugLink.empty())
-    addGnuDebugLink(Obj, Config.AddGnuDebugLink);
+    if (Error E = addGnuDebugLink(Obj, Config.AddGnuDebugLink))
+      return E;
 
   if (Config.AllowBrokenLinks || !Config.BuildIdLinkDir.empty() ||
       Config.BuildIdLinkInput || Config.BuildIdLinkOutput ||

tools/llvm-objcopy/COFF/Object.cpp

@@ -37,12 +37,23 @@ const Symbol *Object::findSymbol(size_t UniqueId) const {
   return It->second;
 }
 
-void Object::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) {
-  Symbols.erase(
-      std::remove_if(std::begin(Symbols), std::end(Symbols),
-                     [ToRemove](const Symbol &Sym) { return ToRemove(Sym); }),
-      std::end(Symbols));
+Error Object::removeSymbols(
+    function_ref<Expected<bool>(const Symbol &)> ToRemove) {
+  Error Errs = Error::success();
+  Symbols.erase(std::remove_if(std::begin(Symbols), std::end(Symbols),
+                               [ToRemove, &Errs](const Symbol &Sym) {
+                                 Expected<bool> ShouldRemove = ToRemove(Sym);
+                                 if (!ShouldRemove) {
+                                   Errs = joinErrors(std::move(Errs),
+                                                     ShouldRemove.takeError());
+                                   return false;
+                                 }
+                                 return *ShouldRemove;
+                               }),
+                std::end(Symbols));
+
   updateSymbols();
+  return Errs;
 }
 
 Error Object::markSymbols() {

tools/llvm-objcopy/COFF/Object.h

@@ -116,7 +116,7 @@ struct Object {
   const Symbol *findSymbol(size_t UniqueId) const;
 
   void addSymbols(ArrayRef<Symbol> NewSymbols);
-  void removeSymbols(function_ref<bool(const Symbol &)> ToRemove);
+  Error removeSymbols(function_ref<Expected<bool>(const Symbol &)> ToRemove);
 
   // Set the Referenced field on all Symbols, based on relocations in
   // all sections.