starter for llvm-objcopy
diff --git a/test/tools/llvm-objcopy/basic-copy.test b/test/tools/llvm-objcopy/basic-copy.test
new file mode 100644
index 0000000..47f3f9e
--- /dev/null
+++ b/test/tools/llvm-objcopy/basic-copy.test
@@ -0,0 +1,43 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy %t %t2
+# RUN: llvm-readobj -sections %t2 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         "00000000"
+
+# CHECK:      Name: .text
+# CHECK-NEXT: Type: SHT_PROGBITS
+# CHECK-NEXT: Flags [
+# CHECK-NEXT:   SHF_ALLOC
+# CHECK-NEXT:   SHF_EXECINSTR
+# CHECK-NEXT: ]
+# CHECK-NEXT: Address:
+# CHECK-NEXT: Offset:
+# CHECK-NEXT: Size: 4
+
+# CHECK: Type: SHT_NULL
+
+# CHECK:      Name: .symtab
+# CHECK-NEXT: Type: SHT_SYMTAB
+# CHECK-NEXT: Flags [
+# CHECK-NEXT: ]
+
+# CHECK:      Name: .strtab
+# CHECK-NEXT: Type: SHT_STRTAB
+# CHECK-NEXT: Flags [
+# CHECK-NEXT: ]
+
+# CHECK:      Name: .shstrtab
+# CHECK-NEXT: Type: SHT_STRTAB
+# CHECK-NEXT: Flags [
+# CHECK-NEXT: ]
diff --git a/tools/LLVMBuild.txt b/tools/LLVMBuild.txt
index e3041a6..232eb71 100644
--- a/tools/LLVMBuild.txt
+++ b/tools/LLVMBuild.txt
@@ -39,6 +39,7 @@
  llvm-mcmarkup
  llvm-modextract
  llvm-nm
+ llvm-objcopy
  llvm-objdump
  llvm-pdbdump
  llvm-profdata
diff --git a/tools/llvm-objcopy/CMakeLists.txt b/tools/llvm-objcopy/CMakeLists.txt
new file mode 100644
index 0000000..d4add0e
--- /dev/null
+++ b/tools/llvm-objcopy/CMakeLists.txt
@@ -0,0 +1,10 @@
+set(LLVM_LINK_COMPONENTS
+  Core
+  Object
+  Support
+  )
+
+add_llvm_tool(llvm-objcopy
+  llvm-objcopy.cpp
+  Object.cpp
+  )
diff --git a/tools/llvm-objcopy/LLVMBuild.txt b/tools/llvm-objcopy/LLVMBuild.txt
new file mode 100644
index 0000000..595bf3a
--- /dev/null
+++ b/tools/llvm-objcopy/LLVMBuild.txt
@@ -0,0 +1,22 @@
+
+;===- ./tools/llvm-objcopy/LLVMBuild.txt -----------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+[component_0]
+type = Tool
+name = llvm-objcopy
+parent = Tools
+required_libraries = Object
diff --git a/tools/llvm-objcopy/Object.cpp b/tools/llvm-objcopy/Object.cpp
new file mode 100644
index 0000000..49a32f8
--- /dev/null
+++ b/tools/llvm-objcopy/Object.cpp
@@ -0,0 +1,299 @@
+//===- Object.cpp -----------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Object.h"
+#include "llvm-objcopy.h"
+
+using namespace llvm;
+using namespace object;
+using namespace ELF;
+
+void Segment::writeHeader(FileOutputBuffer &Out) const {
+  uint8_t *Buf = Out.getBufferStart();
+  Buf += sizeof(Elf64_Ehdr) + Index * sizeof(ELF64LE::Phdr);
+  ELF64LE::Phdr &Phdr = *reinterpret_cast<ELF64LE::Phdr *>(Buf);
+  Phdr.p_type = Type;
+  Phdr.p_flags = Flags;
+  Phdr.p_offset = Offset;
+  Phdr.p_vaddr = VAddr;
+  Phdr.p_paddr = VAddr; // TODO: add PAddr to Segment
+  Phdr.p_filesz = FileSize;
+  Phdr.p_memsz = MemSize;
+  Phdr.p_align = Align;
+}
+
+void Segment::finalize() {
+  auto CompOffset = [](const SectionBase *a, const SectionBase *b) -> bool {
+    return a->Offset < b->Offset;
+  };
+  auto MinElem =
+      std::min_element(std::begin(Sections), std::end(Sections), CompOffset);
+  Offset = (**MinElem).Offset;
+  FileSize = 0;
+  for (auto Section : Sections)
+    if (Section->Type != SHT_NOBITS)
+      FileSize += Section->Size;
+}
+
+void SectionBase::finalizeSize() { }
+
+void SectionBase::writeHeader(FileOutputBuffer &Out) const {
+  uint8_t *Buf = Out.getBufferStart();
+  Buf += HeaderOffset;
+  ELF64LE::Shdr &Shdr = *reinterpret_cast<ELF64LE::Shdr *>(Buf);
+  Shdr.sh_name = NameIndex;
+  Shdr.sh_type = Type;
+  Shdr.sh_flags = Flags;
+  Shdr.sh_addr = Addr;
+  Shdr.sh_offset = Offset;
+  Shdr.sh_size = Size;
+  Shdr.sh_link = Link;
+  Shdr.sh_info = Info;
+  Shdr.sh_addralign = Align;
+  Shdr.sh_entsize = EntrySize;
+}
+
+void Section::initlize(
+  const llvm::object::ELFFile<llvm::object::ELF64LE> &ElfFile,
+  const llvm::object::ELF64LE::Shdr &Shdr) {
+  Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
+}
+
+void Section::finalize() {}
+
+void Section::writeSection(FileOutputBuffer &Out) const {
+  uint8_t *Buf = Out.getBufferStart() + Offset;
+  std::copy(std::begin(Data), std::end(Data), Buf);
+}
+
+void StringTableSection::addString(StringRef Name) { Strings[Name] = 0; }
+void StringTableSection::removeString(StringRef Name) { Strings.erase(Name); }
+Elf64_Word StringTableSection::findIndex(StringRef Name) const {
+  auto Iter = Strings.find(Name);
+  if(Iter == std::end(Strings))
+    error("Invalid string search: " + Name);
+  return Iter->second;
+}
+// This function has some warts to it. There's a raw while loop and a
+// reinterpret_cast.
+void StringTableSection::initlize(
+  const llvm::object::ELFFile<llvm::object::ELF64LE> & ElfFile,
+  const llvm::object::ELF64LE::Shdr &Shdr) {
+  ArrayRef<uint8_t> Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
+  auto Iter = std::begin(Data);
+  auto End = std::end(Data);
+  while (Iter < End) {
+    auto End = std::find(Iter, Data.end(), '\0');
+    addString(StringRef(reinterpret_cast<const char *>(&*Iter), End - Iter));
+    ++End;
+    Iter = End;
+  }
+}
+void StringTableSection::finalizeSize() {
+  Size = 0;
+  for (auto &Name : Strings) {
+    Name.second = Size;
+    // We need to add one on for the null character
+    Size += Name.first.size() + 1;
+  }
+}
+
+// Nothing needs to be done since finalizeSize was already called
+void StringTableSection::finalize() {}
+
+void StringTableSection::writeSection(FileOutputBuffer &Out) const {
+  uint8_t *Buf = Out.getBufferStart() + Offset;
+  for (const auto &Name : Strings) {
+    Buf = std::copy(std::begin(Name.first), std::end(Name.first), Buf);
+    // We need to set the null character and then increment the buffer past it
+    *Buf = 0;
+    Buf++;
+  }
+}
+
+std::unique_ptr<SectionBase> Object::constructSection(Elf64_Word Type) {
+  if (Type == SHT_STRTAB)
+    return make_unique<StringTableSection>();
+  return make_unique<Section>();
+}
+
+void Object::readProgramHeaders(const ELFFile<ELF64LE> &ElfFile) {
+  uint32_t Index = 0;
+  for (const auto &Phdr : unwrapOrError(ElfFile.program_headers())) {
+    Segment Seg;
+    Seg.Type = Phdr.p_type;
+    Seg.Flags = Phdr.p_flags;
+    Seg.Offset = Phdr.p_offset;
+    Seg.VAddr = Phdr.p_vaddr;
+    Seg.FileSize = Phdr.p_filesz;
+    Seg.MemSize = Phdr.p_memsz;
+    Seg.Align = Phdr.p_align;
+    Seg.Index = Index;
+    Index++;
+    Segments.push_back(Seg);
+  }
+}
+
+void Object::readSectionHeaders(const ELFFile<ELF64LE> &ElfFile) {
+  Elf64_Word Index = 0;
+  for (const auto &Shdr : unwrapOrError(ElfFile.sections())) {
+    SecPtr Section = constructSection(Shdr.sh_type);
+    Section->Name = unwrapOrError(ElfFile.getSectionName(&Shdr));
+    Section->Type = Shdr.sh_type;
+    Section->Flags = Shdr.sh_flags;
+    Section->Addr = Shdr.sh_addr;
+    Section->Offset = Shdr.sh_offset;
+    Section->Size = Shdr.sh_size;
+    Section->Link = Shdr.sh_link;
+    Section->Info = Shdr.sh_info;
+    Section->Align = Shdr.sh_addralign;
+    Section->EntrySize = Shdr.sh_entsize;
+    Section->Index = Index;
+    Index++;
+    Section->initlize(ElfFile, Shdr);
+    for (auto &Phdr : Segments) {
+      if (Phdr.Offset < Section->Offset &&
+          Phdr.Offset + Phdr.FileSize > Section->Offset) {
+        Phdr.addSection(&*Section);
+        break;
+      }
+    }
+    Sections.push_back(std::move(Section));
+  }
+}
+
+size_t Object::totalSize() const {
+  // We already have the section header offset so we can calculate the total
+  // size by just adding up the size of each section header;
+  return SHOffset + Sections.size() * sizeof(ELF64LE::Shdr);
+}
+
+Object::Object(const ELFObjectFile<ELF64LE> &Obj) {
+  const auto &ElfFile = *Obj.getELFFile();
+  const auto &Ehdr = *ElfFile.getHeader();
+
+  std::copy(Ehdr.e_ident, Ehdr.e_ident + 16, Ident);
+  Type = Ehdr.e_type;
+  Machine = Ehdr.e_machine;
+  Version = Ehdr.e_version;
+  Entry = Ehdr.e_entry;
+  Flags = Ehdr.e_flags;
+
+  readProgramHeaders(ElfFile);
+  readSectionHeaders(ElfFile);
+
+  // If there is a .shstrtab section we have read it in by now. Now we want to
+  // set the appropriete pointer.
+  // TODO: make this using dyn_cast
+  if (Ehdr.e_shstrndx != SHN_UNDEF)
+    SectionNames = (StringTableSection *)&*Sections[Ehdr.e_shstrndx];
+  else
+    SectionNames = nullptr;
+}
+
+void Object::finalize() {
+  // Put allocated sections first in address order.
+  // Maintain ordering of previous non-allocated sections.
+  auto CompareSections = [](const SecPtr &a, const SecPtr &b) {
+    if (a->Flags & SHF_ALLOC) {
+      if (b->Flags & SHF_ALLOC)
+        return a->Addr < b->Addr;
+      return true;
+    }
+    return a->Index < b->Index;
+  };
+  std::sort(std::begin(Sections), std::end(Sections), CompareSections);
+
+  // Ungracefully handle an annoying optimization.
+  for (const auto &Section : Sections) {
+    // Sometimes a bit of string compression occurs on section names that reuse
+    // part of a larger section name for a smaller section name. For instance
+    // ".got.plt" can be used for the name index of ".got.plt" and ".plt".
+    // The quickest fix for this is to add all the names before finalization.
+    SectionNames->addString(Section->Name);
+  }
+
+  // The size of each section must be finalized before offsets and indexs can
+  // be decided.
+  for (auto &Section : Sections)
+    Section->finalizeSize();
+
+  // Decide file offsets and indexs
+  size_t PhdrSize = Segments.size() * sizeof(ELF64LE::Phdr);
+  // After the header and the program headers we can put section data.
+  Elf64_Off Offset = sizeof(ELF64LE::Ehdr) + PhdrSize;
+  Elf64_Word Index = 0;
+  for (auto &Section : Sections) {
+    Section->Offset = Offset;
+    Section->Index = Index;
+    if (Section->Type != SHT_NOBITS)
+      Offset += Section->Size;
+    Index++;
+  }
+
+  // 'offset' should now be just after all the section data so we should set the
+  // section header table offset to be exactly here
+  SHOffset = Offset;
+
+  // If there is a SectionNames finalize it first so that we can assign name
+  // indexes.
+  if(SectionNames) SectionNames->finalize();
+
+  // Finally now that all offsets and indexes have been set we can finalize any
+  // reamining issues.
+  for (auto &Section : Sections) {
+    Section->HeaderOffset = Offset;
+    Offset += sizeof(ELF64LE::Shdr);
+    if(SectionNames)
+      Section->NameIndex = SectionNames->findIndex(Section->Name);
+    Section->finalize();
+  }
+}
+
+void Object::writeHeader(FileOutputBuffer &Out) const {
+  uint8_t *Buf = Out.getBufferStart();
+  ELF64LE::Ehdr &Ehdr = *reinterpret_cast<ELF64LE::Ehdr *>(Buf);
+
+  std::copy(Ident, Ident + 16, Ehdr.e_ident);
+  Ehdr.e_type = Type;
+  Ehdr.e_machine = Machine;
+  Ehdr.e_version = Version;
+  Ehdr.e_entry = Entry;
+  Ehdr.e_phoff = sizeof(ELF64LE::Ehdr);
+  Ehdr.e_shoff = SHOffset;
+  Ehdr.e_flags = Flags;
+  Ehdr.e_ehsize = sizeof(ELF64LE::Ehdr);
+  Ehdr.e_phentsize = sizeof(ELF64LE::Phdr);
+  Ehdr.e_phnum = Segments.size();
+  Ehdr.e_shentsize = sizeof(ELF64LE::Shdr);
+  Ehdr.e_shnum = Sections.size();
+  Ehdr.e_shstrndx = SectionNames->Index;
+}
+
+void Object::writeProgramHeaders(FileOutputBuffer &Out) const {
+  for (auto &Phdr : Segments)
+    Phdr.writeHeader(Out);
+}
+
+void Object::writeSectionHeaders(FileOutputBuffer &Out) const {
+  for (auto &Section : Sections)
+    Section->writeHeader(Out);
+}
+
+void Object::writeSectionData(FileOutputBuffer &Out) const {
+  for (auto &Section : Sections)
+    Section->writeSection(Out);
+}
+
+void Object::write(FileOutputBuffer &Out) {
+  writeHeader(Out);
+  writeProgramHeaders(Out);
+  writeSectionData(Out);
+  writeSectionHeaders(Out);
+}
diff --git a/tools/llvm-objcopy/Object.h b/tools/llvm-objcopy/Object.h
new file mode 100644
index 0000000..53224df
--- /dev/null
+++ b/tools/llvm-objcopy/Object.h
@@ -0,0 +1,129 @@
+//===- Object.h -------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_OBJCOPY_OBJECT_H
+#define LLVM_OBJCOPY_OBJECT_H
+
+#include "llvm/Object/Binary.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/ELF.h"
+#include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/TargetSelect.h"
+
+class StringTableSection;
+
+class SectionBase {
+public:
+  llvm::StringRef Name;
+  llvm::ELF::Elf64_Word NameIndex;
+  llvm::ELF::Elf64_Word Type;
+  llvm::ELF::Elf64_Xword Flags;
+  llvm::ELF::Elf64_Xword Size;
+  llvm::ELF::Elf64_Xword Link;
+  llvm::ELF::Elf64_Addr Addr;
+  llvm::ELF::Elf64_Off Offset;
+  llvm::ELF::Elf64_Off Info;
+  llvm::ELF::Elf64_Xword Align;
+  llvm::ELF::Elf64_Word EntrySize;
+  llvm::ELF::Elf64_Half Index;
+  llvm::ELF::Elf64_Off HeaderOffset;
+
+  virtual ~SectionBase() {}
+  // TODO: make initlize be based on file and section header
+  virtual void initlize(
+    const llvm::object::ELFFile<llvm::object::ELF64LE> &elfFile,
+    const llvm::object::ELF64LE::Shdr &) = 0;
+  virtual void finalize() = 0;
+  virtual void finalizeSize();
+  // TODO: make this not crappy
+  void writeHeader(llvm::FileOutputBuffer &) const;
+  virtual void writeSection(llvm::FileOutputBuffer &) const = 0;
+};
+
+class Segment {
+private:
+  std::vector<const SectionBase *> Sections;
+
+public:
+  llvm::ELF::Elf64_Word Type;
+  llvm::ELF::Elf64_Off Offset;
+  llvm::ELF::Elf64_Addr VAddr;
+  llvm::ELF::Elf64_Xword FileSize;
+  llvm::ELF::Elf64_Xword MemSize;
+  llvm::ELF::Elf64_Word Flags;
+  llvm::ELF::Elf64_Xword Align;
+  uint32_t Index;
+
+  void addSection(const SectionBase* sec) { Sections.push_back(sec); }
+  void writeHeader(llvm::FileOutputBuffer &) const;
+  void finalize();
+};
+
+class Section : public SectionBase {
+private:
+  llvm::ArrayRef<uint8_t> Data;
+
+public:
+  virtual void initlize(
+    const llvm::object::ELFFile<llvm::object::ELF64LE> &,
+    const llvm::object::ELF64LE::Shdr &) override;
+  void finalize() override;
+  void writeSection(llvm::FileOutputBuffer &) const override;
+};
+
+class StringTableSection : public SectionBase {
+private:
+  std::map<llvm::StringRef, uint32_t> Strings;
+
+public:
+  void addString(llvm::StringRef);
+  void removeString(llvm::StringRef);
+  llvm::ELF::Elf64_Word findIndex(llvm::StringRef) const;
+  virtual void initlize(
+    const llvm::object::ELFFile<llvm::object::ELF64LE> &,
+    const llvm::object::ELF64LE::Shdr &) override;
+  void finalizeSize() override;
+  void finalize() override;
+  void writeSection(llvm::FileOutputBuffer &) const override;
+};
+
+class Object {
+private:
+  typedef std::unique_ptr<SectionBase> SecPtr;
+
+  StringTableSection *SectionNames;
+  std::vector<SecPtr> Sections;
+  llvm::SmallVector<Segment, 11> Segments;
+
+  SecPtr constructSection(llvm::ELF::Elf64_Word);
+  void readProgramHeaders(const llvm::object::ELFFile<llvm::object::ELF64LE> &);
+  void readSectionHeaders(const llvm::object::ELFFile<llvm::object::ELF64LE> &);
+  void writeHeader(llvm::FileOutputBuffer &) const;
+  void writeProgramHeaders(llvm::FileOutputBuffer &) const;
+  void writeSectionData(llvm::FileOutputBuffer &) const;
+  void writeSectionHeaders(llvm::FileOutputBuffer &) const;
+
+public:
+
+  uint8_t Ident[16];
+  llvm::ELF::Elf64_Half Type;
+  llvm::ELF::Elf64_Half Machine;
+  llvm::ELF::Elf64_Word Version;
+  llvm::ELF::Elf64_Addr Entry;
+  llvm::ELF::Elf64_Off SHOffset;
+  llvm::ELF::Elf64_Word Flags;
+
+  Object(const llvm::object::ELFObjectFile<llvm::object::ELF64LE>&);
+  size_t totalSize() const;
+  void finalize();
+  void write(llvm::FileOutputBuffer &);
+};
+
+#endif
diff --git a/tools/llvm-objcopy/llvm-objcopy.cpp b/tools/llvm-objcopy/llvm-objcopy.cpp
new file mode 100644
index 0000000..004312d
--- /dev/null
+++ b/tools/llvm-objcopy/llvm-objcopy.cpp
@@ -0,0 +1,113 @@
+//===- llvm-objcopy.cpp -----------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+#include "Object.h"
+#include "llvm-objcopy.h"
+
+#include <memory>
+#include <string>
+#include <system_error>
+
+using namespace llvm;
+using namespace object;
+using namespace ELF;
+
+// The name this program was invoked as.
+static StringRef ToolName;
+
+namespace llvm {
+
+LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
+  errs() << ToolName << ": " << Message << ".\n";
+  errs().flush();
+  exit(1);
+}
+
+LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code EC) {
+  assert(EC);
+  errs() << ToolName << ": '" << File << "': " << EC.message() << ".\n";
+  exit(1);
+}
+
+LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, llvm::Error E) {
+  assert(E);
+  std::string Buf;
+  raw_string_ostream OS(Buf);
+  logAllUnhandledErrors(std::move(E), OS, "");
+  OS.flush();
+  errs() << ToolName << ": '" << File << "': " << Buf;
+  exit(1);
+}
+
+}
+
+cl::opt<std::string> InputFilename(cl::Positional, cl::desc("<input>"));
+cl::opt<std::string> OutputFilename(cl::Positional, cl::desc("<output>"),
+                                    cl::init("-"));
+
+void CopyBinary(const ELFObjectFile<ELF64LE> &ObjFile) {
+  std::unique_ptr<FileOutputBuffer> Buffer;
+  Object Obj{ObjFile};
+  Obj.finalize();
+
+  ErrorOr<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
+      FileOutputBuffer::create(OutputFilename, Obj.totalSize(),
+                               FileOutputBuffer::F_executable);
+  if (auto EC = BufferOrErr.getError())
+    error("failed to open " + OutputFilename);
+  else
+    Buffer = std::move(*BufferOrErr);
+
+  std::error_code EC;
+  std::unique_ptr<tool_output_file> Out =
+      make_unique<tool_output_file>(OutputFilename.data(), EC, sys::fs::F_None);
+  if (EC)
+    report_fatal_error(EC.message());
+  // now if the program fails for any reason the output file will be deleted
+
+  Obj.write(*Buffer);
+  if (auto EC = Buffer->commit())
+    reportError(OutputFilename, EC);
+  Out->keep();
+}
+
+int main(int argc, char **argv) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
+  PrettyStackTraceProgram X(argc, argv);
+  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+
+  cl::ParseCommandLineOptions(argc, argv, "llvm objcopy utility\n");
+
+  ToolName = argv[0];
+
+  if (InputFilename.empty()) {
+    cl::PrintHelpMessage();
+    return 2;
+  }
+
+  Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(InputFilename);
+  if (!BinaryOrErr)
+    reportError(InputFilename, BinaryOrErr.takeError());
+
+  Binary &Binary = *BinaryOrErr.get().getBinary();
+
+  if (ELFObjectFile<ELF64LE> *o = dyn_cast<ELFObjectFile<ELF64LE>>(&Binary)) {
+    CopyBinary(*o);
+  } else
+    reportError(InputFilename, object_error::invalid_file_type);
+
+  return 0;
+}
diff --git a/tools/llvm-objcopy/llvm-objcopy.h b/tools/llvm-objcopy/llvm-objcopy.h
new file mode 100644
index 0000000..299f99c
--- /dev/null
+++ b/tools/llvm-objcopy/llvm-objcopy.h
@@ -0,0 +1,31 @@
+//===- llvm-objcopy.h -------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// 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
+
+namespace llvm {
+
+extern LLVM_ATTRIBUTE_NORETURN 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