[objdump] Add --private-headers, -p.

This currently prints the ELF program headers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171649 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index 24dc9c9..9958dad 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -28,6 +28,7 @@
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/COFF.h"
+#include "llvm/Object/ELF.h"
 #include "llvm/Object/MachO.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Casting.h"
@@ -112,6 +113,14 @@
 UnwindInfoShort("u", cl::desc("Alias for --unwind-info"),
                 cl::aliasopt(UnwindInfo));
 
+static cl::opt<bool>
+PrivateHeaders("private-headers",
+               cl::desc("Display format specific file headers"));
+
+static cl::alias
+PrivateHeadersShort("p", cl::desc("Alias for --private-headers"),
+                    cl::aliasopt(PrivateHeaders));
+
 static StringRef ToolName;
 
 bool llvm::error(error_code ec) {
@@ -627,6 +636,8 @@
     PrintSymbolTable(o);
   if (UnwindInfo)
     PrintUnwindInfo(o);
+  if (PrivateHeaders && o->isELF())
+    printELFFileHeader(o);
 }
 
 /// @brief Dump each object file in \a a;
@@ -706,7 +717,8 @@
       && !SectionHeaders
       && !SectionContents
       && !SymbolTable
-      && !UnwindInfo) {
+      && !UnwindInfo
+      && !PrivateHeaders) {
     cl::PrintHelpMessage();
     return 2;
   }