[llvm-readelf] Make llvm-readelf more compatible with GNU readelf.

Summary:
This change adds a bunch of options that GNU readelf supports. There is one breaking change when invoked as `llvm-readobj`, and three breaking changes when invoked as `llvm-readelf`:
 - Add --all (implies --file-header, --program-headers, etc.)
 - [Breaking] -a is --all instead of --arm-attributes
 - Add --file-header as an alias for --file-headers
 - Replace --sections with --sections-headers, keeping --sections as an alias for it
 - Add --relocs as an alias for --relocations
 - Add --dynamic as an alias for --dynamic-table
 - Add --segments as an alias for --program-headers
 - Add --section-groups as an alias for --elf-section-groups
 - Add --dyn-syms as an alias for --dyn-symbols
 - Add --syms as an alias for --symbols
 - Add --histogram as an alias for --elf-hash-histogram
 - [Breaking] When invoked as `llvm-readelf`, -s is --symbols instead of --sections
 - [Breaking] When invoked as `llvm-readelf`, -t is no longer an alias for --symbols

Reviewers: MaskRay, phosek, mcgrathr, jhenderson

Reviewed By: MaskRay, jhenderson

Subscribers: sbc100, aheejin, edd, jhenderson, silvas, echristo, compnerd, kristina, javed.absar, kristof.beyls, llvm-commits, Bigcheese

Differential Revision: https://reviews.llvm.org/D54124

llvm-svn: 346685
diff --git a/llvm/tools/llvm-readobj/MachODumper.cpp b/llvm/tools/llvm-readobj/MachODumper.cpp
index 69ef155..35e4cfc 100644
--- a/llvm/tools/llvm-readobj/MachODumper.cpp
+++ b/llvm/tools/llvm-readobj/MachODumper.cpp
@@ -32,7 +32,7 @@
       : ObjDumper(Writer), Obj(Obj) {}
 
   void printFileHeaders() override;
-  void printSections() override;
+  void printSectionHeaders() override;
   void printRelocations() override;
   void printSymbols() override;
   void printDynamicSymbols() override;
@@ -59,7 +59,7 @@
 
   void printRelocation(const MachOObjectFile *Obj, const RelocationRef &Reloc);
 
-  void printSections(const MachOObjectFile *Obj);
+  void printSectionHeaders(const MachOObjectFile *Obj);
 
   const MachOObjectFile *Obj;
 };
@@ -428,11 +428,9 @@
   W.printFlags("Flags", Header.flags, makeArrayRef(MachOHeaderFlags));
 }
 
-void MachODumper::printSections() {
-  return printSections(Obj);
-}
+void MachODumper::printSectionHeaders() { return printSectionHeaders(Obj); }
 
-void MachODumper::printSections(const MachOObjectFile *Obj) {
+void MachODumper::printSectionHeaders(const MachOObjectFile *Obj) {
   ListScope Group(W, "Sections");
 
   int SectionIndex = -1;