[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, 10 insertions, 3 deletions

diff --git a/llvm/tools/llvm-objdump/COFFDump.cpp b/llvm/tools/llvm-objdump/COFFDump.cpp
index b1beedc..e1b3847 100644
--- a/llvm/tools/llvm-objdump/COFFDump.cpp
+++ b/llvm/tools/llvm-objdump/COFFDump.cpp
@@ -37,13 +37,15 @@ template <typename T> struct EnumEntry {
   StringRef Name;
 };
 
-class COFFDumper {
+class COFFDumper : public Dumper {
 public:
-  explicit COFFDumper(const llvm::object::COFFObjectFile &Obj) : Obj(Obj) {
+  explicit COFFDumper(const llvm::object::COFFObjectFile &O)
+      : Dumper(O), Obj(O) {
     Is64 = !Obj.getPE32Header();
   }
 
   template <class PEHeader> void printPEHeader(const PEHeader &Hdr) const;
+  void printPrivateHeaders(bool MachOOnlyFirst) override;
 
 private:
   template <typename T> FormattedNumber formatAddr(T V) const {
@@ -59,6 +61,11 @@ private:
 };
 } // namespace
 
+std::unique_ptr<Dumper>
+objdump::createCOFFDumper(const object::COFFObjectFile &Obj) {
+  return std::make_unique<COFFDumper>(Obj);
+}
+
 constexpr EnumEntry<uint16_t> PEHeaderMagic[] = {
     {uint16_t(COFF::PE32Header::PE32), "PE32"},
     {uint16_t(COFF::PE32Header::PE32_PLUS), "PE32+"},
@@ -764,7 +771,7 @@ void objdump::printCOFFUnwindInfo(const COFFObjectFile *Obj) {
   }
 }
 
-void objdump::printCOFFFileHeader(const COFFObjectFile &Obj) {
+void COFFDumper::printPrivateHeaders(bool MachOOnlyFirst) {
   COFFDumper CD(Obj);
   const uint16_t Cha = Obj.getCharacteristics();
   outs() << "Characteristics 0x" << Twine::utohexstr(Cha) << '\n';