[llvm-nm] Fix how inlined dylibs are reported from tbd files (#134498)

An Inlined library is a dylib that is reexported from an umbrella or
top-level library. When this is encoded in tbd files, ensure we are
reading the symbol table from the inlined library when
`--add-inlinedinfo` is used as opposed to the top-level lib.

resolves: rdar://147767733

Author: cyndyishida

llvm/include/llvm/Object/TapiUniversal.h

@@ -110,9 +110,11 @@ class TapiUniversal : public Binary {
   static bool classof(const Binary *v) { return v->isTapiUniversal(); }
 
 private:
+  /// Attributes of a library that is inlined into a single TBD file.
   struct Library {
-    StringRef InstallName;
-    MachO::Architecture Arch;
+    const StringRef InstallName;
+    const MachO::Architecture Arch;
+    const std::optional<size_t> DocumentIdx;
   };
 
   std::unique_ptr<MachO::InterfaceFile> ParsedFile;

llvm/lib/Object/TapiUniversal.cpp

@@ -29,25 +29,34 @@ TapiUniversal::TapiUniversal(MemoryBufferRef Source, Error &Err)
   }
   ParsedFile = std::move(Result.get());
 
-  auto FlattenObjectInfo = [this](const auto &File) {
+  auto FlattenObjectInfo = [this](const auto &File,
+                                  std::optional<size_t> DocIdx = std::nullopt) {
     StringRef Name = File->getInstallName();
     for (const Architecture Arch : File->getArchitectures())
-      Libraries.emplace_back(Library({Name, Arch}));
+      Libraries.emplace_back(Library({Name, Arch, DocIdx}));
   };
-
   FlattenObjectInfo(ParsedFile);
   // Get inlined documents from tapi file.
+  size_t DocIdx = 0;
   for (const std::shared_ptr<InterfaceFile> &File : ParsedFile->documents())
-    FlattenObjectInfo(File);
+    FlattenObjectInfo(File, DocIdx++);
 }
 
 TapiUniversal::~TapiUniversal() = default;
 
 Expected<std::unique_ptr<TapiFile>>
 TapiUniversal::ObjectForArch::getAsObjectFile() const {
-  return std::make_unique<TapiFile>(Parent->getMemoryBufferRef(),
-                                    *Parent->ParsedFile,
-                                    Parent->Libraries[Index].Arch);
+  const auto &InlinedDocuments = Parent->ParsedFile->documents();
+  const Library &CurrLib = Parent->Libraries[Index];
+  assert(
+      (isTopLevelLib() || (CurrLib.DocumentIdx.has_value() &&
+                           (InlinedDocuments.size() > *CurrLib.DocumentIdx))) &&
+      "Index into documents exceeds the container for them");
+  InterfaceFile *IF = isTopLevelLib()
+                          ? Parent->ParsedFile.get()
+                          : InlinedDocuments[*CurrLib.DocumentIdx].get();
+  return std::make_unique<TapiFile>(Parent->getMemoryBufferRef(), *IF,
+                                    CurrLib.Arch);
 }
 
 Expected<std::unique_ptr<TapiUniversal>>

llvm/test/tools/llvm-nm/tapi-files.test

@@ -45,14 +45,8 @@ V3-NEXT: 0000000000000000 S _OBJC_METACLASS_$_NSString
 V3-NEXT: 0000000000000000 S _sym1
 V3-NEXT: 0000000000000000 S _sym2
 V3: /usr/lib/liba.dylib (for architecture x86_64):
-V3-NEXT: 0000000000000000 S _OBJC_CLASS_$_NSBlockPredicate
-V3-NEXT: 0000000000000000 S _OBJC_CLASS_$_NSString
-V3-NEXT: 0000000000000000 S _OBJC_EHTYPE_$_NSString
-V3-NEXT: 0000000000000000 S _OBJC_IVAR_$_NSBlockPredicate._block
-V3-NEXT: 0000000000000000 S _OBJC_METACLASS_$_NSBlockPredicate
-V3-NEXT: 0000000000000000 S _OBJC_METACLASS_$_NSString
-V3-NEXT: 0000000000000000 S _sym1
-V3-NEXT: 0000000000000000 S _sym2
+V3-NEXT: 0000000000000000 S _sym10
+V3-NEXT: 0000000000000000 S _sym11
 
 V4: /u/l/libFoo.dylib (for architecture i386):
 V4-NEXT: 00000000 S _sym1