Reland "[LLVM][llvm-objcopy] Added basic plumbing to get things started"

As discussed on llvm-dev I've implemented the first basic steps towards
llvm-objcopy/llvm-objtool (name pending).

This change adds the ability to copy (without modification) 64-bit
little endian ELF executables that have SHT_PROGBITS, SHT_NOBITS,
SHT_NULL and SHT_STRTAB sections.

Patch by Jake Ehrlich

Differential Revision: https://reviews.llvm.org/D33964

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309643 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 32 insertions, 0 deletions

diff --git a/tools/llvm-objcopy/llvm-objcopy.h b/tools/llvm-objcopy/llvm-objcopy.h
new file mode 100644
index 00000000000..de7bf367ac8
--- /dev/null
+++ b/tools/llvm-objcopy/llvm-objcopy.h
@@ -0,0 +1,32 @@
+//===- llvm-objcopy.h -------------------------------------------*- C++ -*-===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_OBJCOPY_H
+#define LLVM_OBJCOPY_H
+
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+
+LLVM_ATTRIBUTE_NORETURN extern void error(Twine Message);
+
+// This is taken from llvm-readobj.
+// [see here](llvm/tools/llvm-readobj/llvm-readobj.h:38)
+template <class T> T unwrapOrError(Expected<T> EO) {
+  if (EO)
+    return *EO;
+  std::string Buf;
+  raw_string_ostream OS(Buf);
+  logAllUnhandledErrors(EO.takeError(), OS, "");
+  OS.flush();
+  error(Buf);
+}
+}
+
+#endif