Implements low-level object file format specific output for COFF and
ELF with support for:

- File headers
- Section headers + data
- Relocations
- Symbols
- Unwind data (only COFF/Win64)

The output format follows a few rules:
- Values are almost always output one per line (as elf-dump/coff-dump already do). - Many values are translated to something readable (like enum names), with the raw value in parentheses.
- Hex numbers are output in uppercase, prefixed with "0x".
- Flags are sorted alphabetically.
- Lists and groups are always delimited.

Example output:
---------- snip ----------
Sections [
  Section {
    Index: 1
    Name: .text (5)
    Type: SHT_PROGBITS (0x1)
    Flags [ (0x6)
      SHF_ALLOC (0x2)
      SHF_EXECINSTR (0x4)
    ]
    Address: 0x0
    Offset: 0x40
    Size: 33
    Link: 0
    Info: 0
    AddressAlignment: 16
    EntrySize: 0
    Relocations [
      0x6 R_386_32 .rodata.str1.1 0x0
      0xB R_386_PC32 puts 0x0
      0x12 R_386_32 .rodata.str1.1 0x0
      0x17 R_386_PC32 puts 0x0
    ]
    SectionData (
      0000: 83EC04C7 04240000 0000E8FC FFFFFFC7  |.....$..........|
      0010: 04240600 0000E8FC FFFFFF31 C083C404  |.$.........1....|
      0020: C3                                   |.|
    )
  }
]
---------- snip ----------

Relocations and symbols can be output standalone or together with the section header as displayed in the example.
This feature set supports all tests in test/MC/COFF and test/MC/ELF (and I suspect all additional tests using elf-dump), making elf-dump and coff-dump deprecated.

Patch by Nico Rieck!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178679 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-readobj/Error.h b/tools/llvm-readobj/Error.h
new file mode 100644
index 0000000..cf68da8
--- /dev/null
+++ b/tools/llvm-readobj/Error.h
@@ -0,0 +1,48 @@
+//===- Error.h - system_error extensions for llvm-readobj -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This declares a new error_category for the llvm-readobj tool.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_READOBJ_ERROR_H
+#define LLVM_READOBJ_ERROR_H
+
+#include "llvm/Support/system_error.h"
+
+namespace llvm {
+
+const error_category &readobj_category();
+
+struct readobj_error {
+  enum _ {
+    success = 0,
+    file_not_found,
+    unsupported_file_format,
+    unrecognized_file_format,
+    unsupported_obj_file_format,
+    unknown_symbol
+  };
+  _ v_;
+
+  readobj_error(_ v) : v_(v) {}
+  explicit readobj_error(int v) : v_(_(v)) {}
+  operator int() const {return v_;}
+};
+
+inline error_code make_error_code(readobj_error e) {
+  return error_code(static_cast<int>(e), readobj_category());
+}
+
+template <> struct is_error_code_enum<readobj_error> : true_type { };
+template <> struct is_error_code_enum<readobj_error::_> : true_type { };
+
+} // namespace llvm
+
+#endif