llvm-readobj: implement MachODumper::printNeededLibraries

[chilledheart]

Most code of MachODumper::printNeededLibraries keeps the same with ELFDumper::printNeededLibraries.

[chilledheart]

Ping?

[kledzik]

tools/llvm-readobj/MachODumper.cpp

605

LC_ID_DYLIB is not a "needed library". It is the DT_SONAME of the dylib.

617

Why sort? The order is important in mach-o. The symbol table entries for undefined symbols contain a one byte "ordinal" which is the index into this ordered list.

[chilledheart]

remove std::stable_sort and LC_ID_DYLIB items

[chilledheart]

apply some minor improvements

I saw the LC_ID_DYLIB items in the output of otool -L command, so I thought
they were needed to be printed (double-checked with cctool source code, version 862).
I have removed this, anyway.

The file mach-o/loader.h states that struct fvmlib is obsoleted,
so there is no need to add the support for LC_IDFVMLIB and LC_LOADFVMLIB.

[chilledheart]

Ping?

tools/llvm-readobj/MachODumper.cpp

617

removed

tools/llvm-readobj/MachODumper.cpp

public:
 
   void printFileHeaders() override;
   void printSections() override;
   void printRelocations() override;
   void printSymbols() override;
   void printDynamicSymbols() override;
   void printUnwindInfo() override;
 
+  void printNeededLibraries() override;
+
 private:
   template<class MachHeader>
   void printFileHeaders(const MachHeader &Header);
 
   void printSymbol(const SymbolRef &Symbol);
 
   void printRelocation(const RelocationRef &Reloc);
 
void MachODumper::printSymbol(const SymbolRef &Symbol) {
   W.printFlags("Flags", static_cast<uint16_t>(MOSymbol.Flags & ~0xF),
                makeArrayRef(MachOSymbolFlags));
   W.printHex("Value", MOSymbol.Value);
 }
 
 void MachODumper::printUnwindInfo() {
   W.startLine() << "UnwindInfo not implemented.\n";
 }
+
+void MachODumper::printNeededLibraries() {
+  ListScope D(W, "NeededLibraries");
+
+  typedef std::vector<StringRef> LibsTy;
+  LibsTy Libs;
+
+  uint32_t NumOfCommands =
+      Obj->is64Bit() ? Obj->getHeader64().ncmds : Obj->getHeader().ncmds;
+  MachOObjectFile::LoadCommandInfo Command = Obj->getFirstLoadCommandInfo();
+  MachO::dylib_command DylibCommand;
+  uint32_t LoadCommandType;
+  for (uint32_t i = 0; i != NumOfCommands;
+       ++i, Command = Obj->getNextLoadCommandInfo(Command), LoadCommandType = Command.C.cmd) {
+    if (LoadCommandType == MachO::LC_LOAD_DYLIB ||
+        LoadCommandType == MachO::LC_LOAD_WEAK_DYLIB ||
+        LoadCommandType == MachO::LC_REEXPORT_DYLIB ||
+        LoadCommandType == MachO::LC_LOAD_UPWARD_DYLIB ||
+        LoadCommandType == MachO::LC_LAZY_LOAD_DYLIB) {
+      DylibCommand = Obj->getDylibIDLoadCommand(Command);
+      Libs.push_back(Command.Ptr + DylibCommand.dylib.name);
+    }
+    if (i == NumOfCommands -1)
+      break;
+  }
+
+  for (LibsTy::const_iterator I = Libs.begin(), E = Libs.end(); I != E; ++I) {
+    outs() << "  " << *I << "\n";
+  }
+}