[llvm] [llvm-objcopy] MachO: Fix section finding policy for object files (PR #127604)

[Alexander Shaposhnikov via llvm-commits]

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@@ -360,6 +360,12 @@ static Error addSection(const NewSectionInfo &NewSection, Object &Obj) {
 static Expected<Section &> findSection(StringRef SecName, Object &O) {
   StringRef SegName;
   std::tie(SegName, SecName) = SecName.split(",");
+  if (O.Header.FileType == MachO::HeaderFileType::MH_OBJECT) {
+    for (const auto& LC : O.LoadCommands)
+      for (const auto& Sec : LC.Sections)
+        if (Sec->Segname == SegName && Sec->Sectname == SecName)
+          return *Sec;
+  }
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alexander-shaposhnikov wrote:

1/ should not fall back on the old code path, let's return an error if the section has not been found.
2/ would be good to add comments for the reader why we have 2 cases here (mh_object vs the rest)

https://github.com/llvm/llvm-project/pull/127604