[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, 15 insertions, 0 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.h b/llvm/tools/llvm-objdump/llvm-objdump.h
index ffc1361..fd75f55 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.h
+++ b/llvm/tools/llvm-objdump/llvm-objdump.h
@@ -18,6 +18,7 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/FormattedStream.h"
+#include <memory>
 
 namespace llvm {
 class StringRef;
@@ -30,6 +31,12 @@ class Arg;
 namespace object {
 class RelocationRef;
 struct VersionEntry;
+
+class COFFObjectFile;
+class ELFObjectFileBase;
+class MachOObjectFile;
+class WasmObjectFile;
+class XCOFFObjectFile;
 } // namespace object
 
 namespace objdump {
@@ -71,10 +78,12 @@ class Dumper {
 
 public:
   Dumper(const object::ObjectFile &O) : O(O) {}
+  virtual ~Dumper() {}
 
   void reportUniqueWarning(Error Err);
   void reportUniqueWarning(const Twine &Msg);
 
+  virtual void printPrivateHeaders(bool MachOOnlyFirst);
   void printSymbolTable(StringRef ArchiveName,
                         StringRef ArchitectureName = StringRef(),
                         bool DumpDynamic = false);
@@ -85,6 +94,12 @@ public:
   void printRelocations();
 };
 
+std::unique_ptr<Dumper> createCOFFDumper(const object::COFFObjectFile &Obj);
+std::unique_ptr<Dumper> createELFDumper(const object::ELFObjectFileBase &Obj);
+std::unique_ptr<Dumper> createMachODumper(const object::MachOObjectFile &Obj);
+std::unique_ptr<Dumper> createWasmDumper(const object::WasmObjectFile &Obj);
+std::unique_ptr<Dumper> createXCOFFDumper(const object::XCOFFObjectFile &Obj);
+
 // Various helper functions.
 
 /// Creates a SectionFilter with a standard predicate that conditionally skips