[llvm-objdump] Create ObjectFile specific dumpers

We pay the one-off boilerplate overhead to create `*Dumper` classes that derive
from objdump::Dumper a la llvm-readobj. This has two primary advantages.

First, a lot object file format specific code can be moved from
llvm-objdump.cpp to *Dump.cpp files. Refactor `printPrivateHeaders` as
an example.

Second, with the introduction of ELFDumper<ELFT>, we can simplify
a few dispatch functions in ELFDump.cpp.

In addition, the ObjectFile specific dumpers contains a ObjectFile specific
reference so that we can remove a lot of `cast<*ObjectFile>(Obj)`.

Reviewed By: mtrofin

Differential Revision: https://reviews.llvm.org/D155045

1 files changed, 22 insertions, 2 deletions

diff --git a/llvm/tools/llvm-objdump/MachODump.cpp b/llvm/tools/llvm-objdump/MachODump.cpp
index 0e10403..11fb1cb 100644
--- a/llvm/tools/llvm-objdump/MachODump.cpp
+++ b/llvm/tools/llvm-objdump/MachODump.cpp
@@ -191,8 +191,21 @@ struct SymbolSorter {
     return AAddr < BAddr;
   }
 };
+
+class MachODumper : public Dumper {
+  const object::MachOObjectFile &Obj;
+
+public:
+  MachODumper(const object::MachOObjectFile &O) : Dumper(O), Obj(O) {}
+  void printPrivateHeaders(bool OnlyFirst) override;
+};
 } // namespace
 
+std::unique_ptr<Dumper>
+objdump::createMachODumper(const object::MachOObjectFile &Obj) {
+  return std::make_unique<MachODumper>(Obj);
+}
+
 // Types for the storted data in code table that is built before disassembly
 // and the predicate function to sort them.
 typedef std::pair<uint64_t, DiceRef> DiceTableEntry;
@@ -2142,7 +2155,8 @@ static void printObjcMetaData(MachOObjectFile *O, bool verbose);
 static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
                          StringRef ArchiveMemberName = StringRef(),
                          StringRef ArchitectureName = StringRef()) {
-  Dumper D(*MachOOF);
+  std::unique_ptr<Dumper> D = createMachODumper(*MachOOF);
+
   // If we are doing some processing here on the Mach-O file print the header
   // info.  And don't print it otherwise like in the case of printing the
   // UniversalHeaders or ArchiveHeaders.
@@ -2228,7 +2242,7 @@ static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
   if (DylibId)
     PrintDylibs(MachOOF, true);
   if (SymbolTable)
-    D.printSymbolTable(ArchiveName, ArchitectureName);
+    D->printSymbolTable(ArchiveName, ArchitectureName);
   if (UnwindInfo)
     printMachOUnwindInfo(MachOOF);
   if (PrivateHeaders) {
@@ -10540,6 +10554,12 @@ void objdump::printMachOFileHeader(const object::ObjectFile *Obj) {
   PrintMachHeader(file, Verbose);
 }
 
+void MachODumper::printPrivateHeaders(bool OnlyFirst) {
+  printMachOFileHeader(&Obj);
+  if (!OnlyFirst)
+    printMachOLoadCommands(&Obj);
+}
+
 void objdump::printMachOLoadCommands(const object::ObjectFile *Obj) {
   const MachOObjectFile *file = cast<const MachOObjectFile>(Obj);
   uint32_t filetype = 0;