Index: include/llvm/Object/Compressor.h
===================================================================
--- /dev/null
+++ include/llvm/Object/Compressor.h
@@ -0,0 +1,92 @@
+//===-- Compressor.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_OBJECT_COMPRESSOR_H
+#define LLVM_OBJECT_COMPRESSOR_H
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Compression.h"
+#include "llvm/Support/EndianStream.h"
+
+namespace llvm {
+namespace object {
+
+/// Return the gnu style compressed section name.
+StringRef getDebugSectionName(const StringRef Name, bool IsGnuStyle);
+
+/// Returns if the section can be compressed based on its name (must have a
+/// debug name, starts with .*debug.
+bool isCompressable(StringRef Name);
+
+/// Returns if the section is already compressed based on the section contents
+/// Name and Flags.
+bool isCompressed(StringRef Name, StringRef Contents, uint64_t Flags);
+
+template <typename T>
+void produceCompressedZLibHeader(support::endian::Writer &W,
+                                 uint64_t DecompressedSize, unsigned Align);
+
+template <>
+void produceCompressedZLibHeader<object::ELF64LE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align);
+
+template <>
+void produceCompressedZLibHeader<object::ELF64BE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align);
+
+template <>
+void produceCompressedZLibHeader<object::ELF32LE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align);
+
+template <>
+void produceCompressedZLibHeader<object::ELF32BE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align);
+
+/// Compressor helps to handle compression of compressed sections.
+template <typename T> class Compressor {
+public:
+  void writeHeader(support::endian::Writer &W, uint64_t DecompressedSize,
+                   unsigned Alignment, bool IsGnuStyle) {
+    if (IsGnuStyle) {
+      const StringRef Magic = "ZLIB";
+      W.OS << Magic;
+      support::endian::write(W.OS, DecompressedSize, support::big);
+      return;
+    }
+
+    produceCompressedZLibHeader<T>(W, DecompressedSize, Alignment);
+  }
+
+  /// Uncompress section data to raw buffer provided.
+  /// @param W        Destination buffer stream.
+  Error writeCompressedSectionData(support::endian::Writer &W) {
+    SmallVector<char, 128> CompressedBuffer;
+    auto E = zlib::compress(SectionData, CompressedBuffer);
+    W.OS << StringRef(CompressedBuffer.data(), CompressedBuffer.size()).str();
+    return E;
+  }
+
+  explicit Compressor(StringRef Data) : SectionData(Data) {}
+
+private:
+  StringRef SectionData;
+};
+
+} // end namespace object
+} // end namespace llvm
+
+#endif // LLVM_OBJECT_COMPRESSOR_H
Index: lib/Object/CMakeLists.txt
===================================================================
--- lib/Object/CMakeLists.txt
+++ lib/Object/CMakeLists.txt
@@ -21,6 +21,7 @@
   SymbolSize.cpp
   WasmObjectFile.cpp
   WindowsResource.cpp
+  Compressor.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Object
Index: lib/Object/Compressor.cpp
===================================================================
--- /dev/null
+++ lib/Object/Compressor.cpp
@@ -0,0 +1,113 @@
+//===-- Compressor.cpp ----------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/Compressor.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Support/Compression.h"
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/EndianStream.h"
+
+using namespace llvm;
+using namespace llvm::support::endian;
+using namespace object;
+
+namespace llvm {
+namespace object {
+
+StringRef getDebugSectionName(const StringRef Name, bool IsGnuStyle) {
+
+  if (!Name.startswith(".debug") && !Name.startswith(".zdebug"))
+    return "";
+
+  std::string LookupName = Name.substr(Name.startswith(".debug") ? 1 : 2).str();
+  std::string Dot(".");
+
+  static std::map<std::string, std::tuple<std::string, std::string>> NameMap;
+  auto I = NameMap.find(LookupName);
+  if (I == NameMap.end()) {
+    NameMap.insert(std::pair<std::string, std::tuple<std::string, std::string>>(
+        LookupName,
+        std::make_tuple(Dot + LookupName, (Dot + "z") + LookupName)));
+    I = NameMap.find(LookupName);
+  }
+
+  StringRef debugName, zdebugName;
+  std::tie(debugName, zdebugName) = I->second;
+  return IsGnuStyle ? zdebugName : debugName;
+}
+
+bool isCompressable(StringRef Name) {
+  StringRef DotDebugName = getDebugSectionName(Name, false /* IsGnuStyle */);
+  return DotDebugName.startswith(".debug");
+}
+
+bool isCompressed(StringRef Name, StringRef Contents, uint64_t Flags) {
+  if (!Name.startswith(".debug") && !Name.startswith(".zdebug"))
+    return false;
+
+  StringRef magic = Contents.substr(4);
+  return Name.startswith(".zdebug") || (magic == "ZLIB") ||
+         (Flags & ELF::SHF_COMPRESSED);
+}
+
+template <typename T>
+void writeZLibHeaderReserved(support::endian::Writer &W) {}
+
+template <>
+void writeZLibHeaderReserved<ELF::Elf64_Chdr>(support::endian::Writer &W) {
+  W.write(static_cast<ELF::Elf64_Word>(0)); // ch_reserved field.
+}
+
+template <typename T>
+void produceCompressedZLibHeader2(support::endian::Writer &W,
+                                  uint64_t DecompressedSize, unsigned Align) {
+  T Elf_Chr;
+  W.write(static_cast<decltype(Elf_Chr.ch_type)>(ELF::ELFCOMPRESS_ZLIB));
+  writeZLibHeaderReserved<T>(W);
+  W.write(static_cast<decltype(Elf_Chr.ch_size)>(DecompressedSize));
+  W.write(static_cast<decltype(Elf_Chr.ch_addralign)>(Align));
+}
+
+template <typename T>
+void produceCompressedZLibHeader(support::endian::Writer &W,
+                                 uint64_t DecompressedSize, unsigned Align) {}
+
+template <>
+void produceCompressedZLibHeader<object::ELF64LE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align) {
+  produceCompressedZLibHeader2<ELF::Elf64_Chdr>(W, DecompressedSize, Align);
+}
+
+template <>
+void produceCompressedZLibHeader<object::ELF64BE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align) {
+  produceCompressedZLibHeader2<ELF::Elf64_Chdr>(W, DecompressedSize, Align);
+}
+
+template <>
+void produceCompressedZLibHeader<object::ELF32LE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align) {
+  produceCompressedZLibHeader2<ELF::Elf32_Chdr>(W, DecompressedSize, Align);
+}
+
+template <>
+void produceCompressedZLibHeader<object::ELF32BE>(support::endian::Writer &W,
+                                                  uint64_t DecompressedSize,
+                                                  unsigned Align) {
+  produceCompressedZLibHeader2<ELF::Elf32_Chdr>(W, DecompressedSize, Align);
+}
+
+} // end namespace object
+} // end namespace llvm
Index: tools/llvm-objcopy/ObjcopyOpts.td
===================================================================
--- tools/llvm-objcopy/ObjcopyOpts.td
+++ tools/llvm-objcopy/ObjcopyOpts.td
@@ -16,6 +16,11 @@
 defm output_target : Eq<"output-target">,
                      HelpText<"Format of the output file">,
                      Values<"binary">;
+defm compress_debug_sections : Eq<"compress-debug-sections">,
+                     MetaVarName<"[ none | zlib | zlib-gnu (deprecated) ]">,
+                     HelpText<"Enable zlib-gnu or zlib Compression of DWARF debug sections.">;
+def decompress_debug_sections : Flag<["-", "--"], "decompress-debug-sections">,
+                     HelpText<"Decompress DWARF debug sections.">;
 def O : JoinedOrSeparate<["-"], "O">,
         Alias<output_target>;
 defm split_dwo : Eq<"split-dwo">,
Index: tools/llvm-objcopy/Object.h
===================================================================
--- tools/llvm-objcopy/Object.h
+++ tools/llvm-objcopy/Object.h
@@ -14,7 +14,10 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/MC/StringTableBuilder.h"
+#include "llvm/Object/Compressor.h"
+#include "llvm/Object/Decompressor.h"
 #include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Support/FileOutputBuffer.h"
 #include "llvm/Support/JamCRC.h"
@@ -43,6 +46,44 @@
 class Object;
 struct Symbol;
 
+struct CopyConfig {
+  StringRef OutputFilename;
+  StringRef InputFilename;
+  StringRef OutputFormat;
+  StringRef InputFormat;
+  StringRef BinaryArch;
+
+  StringRef SplitDWO;
+  StringRef AddGnuDebugLink;
+  std::vector<StringRef> ToRemove;
+  std::vector<StringRef> Keep;
+  std::vector<StringRef> OnlyKeep;
+  std::vector<StringRef> AddSection;
+  std::vector<StringRef> SymbolsToLocalize;
+  std::vector<StringRef> SymbolsToGlobalize;
+  std::vector<StringRef> SymbolsToWeaken;
+  std::vector<StringRef> SymbolsToRemove;
+  std::vector<StringRef> SymbolsToKeep;
+  StringMap<StringRef> SectionsToRename;
+  StringMap<StringRef> SymbolsToRename;
+  bool StripAll = false;
+  bool StripAllGNU = false;
+  bool StripDebug = false;
+  bool StripSections = false;
+  bool StripNonAlloc = false;
+  bool StripDWO = false;
+  bool StripUnneeded = false;
+  bool ExtractDWO = false;
+  bool LocalizeHidden = false;
+  bool Weaken = false;
+  bool DiscardAll = false;
+  bool OnlyKeepDebug = false;
+  bool KeepFileSymbols = false;
+  bool DecompressDebugSections = false;
+
+  DebugCompressionType CompressDebugSections = DebugCompressionType::None;
+};
+
 class SectionTableRef {
   MutableArrayRef<std::unique_ptr<SectionBase>> Sections;
 
@@ -190,6 +231,9 @@
 
 template <class ELFT> class ELFWriter : public Writer {
 private:
+  DebugCompressionType CompressDebugSections = DebugCompressionType::None;
+  bool DecompressDebugSections = false;
+
   using Elf_Shdr = typename ELFT::Shdr;
   using Elf_Phdr = typename ELFT::Phdr;
   using Elf_Ehdr = typename ELFT::Ehdr;
@@ -214,8 +258,11 @@
 
   void finalize() override;
   void write() override;
-  ELFWriter(Object &Obj, Buffer &Buf, bool WSH)
-      : Writer(Obj, Buf), WriteSectionHeaders(WSH) {}
+  ELFWriter(Object &Obj, Buffer &Buf, const CopyConfig &Config)
+      : Writer(Obj, Buf), WriteSectionHeaders(!Config.StripSections) {
+    this->CompressDebugSections = Config.CompressDebugSections;
+    this->DecompressDebugSections = Config.DecompressDebugSections;
+  }
 };
 
 class BinaryWriter : public Writer {
@@ -259,6 +306,13 @@
   virtual void removeSymbols(function_ref<bool(const Symbol &)> ToRemove);
   virtual void accept(SectionVisitor &Visitor) const = 0;
   virtual void markSymbols();
+  virtual ArrayRef<uint8_t> *getContents() {
+    assert(false && "Section has no Contents.");
+    return nullptr;
+  }
+  virtual void updateContents(std::unique_ptr<SmallVectorImpl<char>> Contents) {
+    assert(false && "Section has no Contents.");
+  }
 };
 
 class Segment {
@@ -308,6 +362,7 @@
   MAKE_SEC_WRITER_FRIEND
 
   ArrayRef<uint8_t> Contents;
+  std::unique_ptr<SmallVectorImpl<char>> ModifiedContents;
   SectionBase *LinkSection = nullptr;
 
 public:
@@ -317,6 +372,8 @@
   void removeSectionReferences(const SectionBase *Sec) override;
   void initialize(SectionTableRef SecTable) override;
   void finalize() override;
+  ArrayRef<uint8_t> *getContents() override { return &Contents; }
+  void updateContents(std::unique_ptr<SmallVectorImpl<char>> Update) override;
 };
 
 class OwnedDataSection : public SectionBase {
Index: tools/llvm-objcopy/Object.cpp
===================================================================
--- tools/llvm-objcopy/Object.cpp
+++ tools/llvm-objcopy/Object.cpp
@@ -491,6 +491,13 @@
 
 void Section::finalize() { this->Link = LinkSection ? LinkSection->Index : 0; }
 
+void Section::updateContents(std::unique_ptr<SmallVectorImpl<char>> Update) {
+  ModifiedContents = std::move(Update);
+  Size = ModifiedContents->size();
+  const uint8_t *ContentsPtr = (const uint8_t *)ModifiedContents->data();
+  Contents = ArrayRef<uint8_t>(ContentsPtr, Size);
+}
+
 void GnuDebugLinkSection::init(StringRef File, StringRef Data) {
   FileName = sys::path::filename(File);
   // The format for the .gnu_debuglink starts with the file name and is
@@ -1213,6 +1220,51 @@
     reportError(Buf.getName(), errorToErrorCode(std::move(E)));
 }
 
+template <typename T>
+std::unique_ptr<SmallVectorImpl<char>> decompress(StringRef &Name,
+                                                  StringRef Contents) {
+
+  auto ModifiedContents = make_unique<SmallVector<char, 128>>();
+
+  bool Is64Bit = T::Is64Bits;
+  bool IsLittle = (T::TargetEndianness == endianness::little);
+  auto D = object::Decompressor::create(Name, Contents, IsLittle, Is64Bit);
+  if (!D)
+    consumeError(D.takeError());
+
+  auto E = D->resizeAndDecompress(*ModifiedContents.get());
+  consumeError(std::move(E));
+
+  if (const bool IsGnuStyle = Name.startswith(".zdebug"))
+    Name = object::getDebugSectionName(Name, !IsGnuStyle);
+
+  return std::move(ModifiedContents);
+}
+
+template <typename T>
+std::unique_ptr<SmallVectorImpl<char>>
+compress(StringRef &Name, StringRef Contents, uint64_t Align, bool IsGnuStyle) {
+
+  auto ModifiedContents = make_unique<SmallVector<char, 128>>();
+
+  object::endianness E = T::TargetEndianness;
+  raw_svector_ostream OS(*ModifiedContents.get());
+  support::endian::Writer W(OS, E);
+
+  auto C = object::Compressor<T>(Contents);
+  C.writeHeader(W, Contents.size(), Align, IsGnuStyle);
+  auto Error = C.writeCompressedSectionData(W);
+  consumeError(std::move(Error));
+
+  if (ModifiedContents->size() < Contents.size()) {
+    if (IsGnuStyle)
+      Name = object::getDebugSectionName(Name, IsGnuStyle);
+    return std::move(ModifiedContents);
+  }
+
+  return nullptr;
+}
+
 template <class ELFT> void ELFWriter<ELFT>::finalize() {
   // It could happen that SectionNames has been removed and yet the user wants
   // a section header table output. We need to throw an error if a user tries
@@ -1256,10 +1308,37 @@
     }
   }
 
+  bool doDecompress = DecompressDebugSections;
+  bool IsGnuStyle = (CompressDebugSections == DebugCompressionType::GNU);
+  bool doCompress = (CompressDebugSections != DebugCompressionType::None) &&
+                    !DecompressDebugSections;
+
   // Make sure we add the names of all the sections. Importantly this must be
   // done after we decide to add or remove SectionIndexes.
   if (Obj.SectionNames != nullptr)
-    for (const auto &Section : Obj.sections()) {
+    for (auto &Section : Obj.sections()) {
+
+      bool isCompressable = object::isCompressable(Section.Name);
+      if (isCompressable && (doCompress || doDecompress)) {
+        StringRef Contents((const char *)Section.getContents()->data(),
+                           Section.getContents()->size());
+
+        bool isCompressed =
+            object::isCompressed(Section.Name, Contents, Section.Flags);
+        if (doDecompress && isCompressed) {
+          auto ModifiedContents = decompress<ELFT>(Section.Name, Contents);
+          Section.updateContents(std::move(ModifiedContents));
+        } else if (doCompress && !isCompressed) {
+          auto ModifiedContents =
+              compress<ELFT>(Section.Name, Contents, Section.Align, IsGnuStyle);
+          if (ModifiedContents != nullptr) {
+            Section.updateContents(std::move(ModifiedContents));
+            if (!IsGnuStyle)
+              Section.Flags |= ELF::SHF_COMPRESSED;
+          }
+        }
+      }
+
       Obj.SectionNames->addString(Section.Name);
     }
 
Index: tools/llvm-objcopy/llvm-objcopy.cpp
===================================================================
--- tools/llvm-objcopy/llvm-objcopy.cpp
+++ tools/llvm-objcopy/llvm-objcopy.cpp
@@ -115,41 +115,6 @@
   StripOptTable() : OptTable(StripInfoTable, true) {}
 };
 
-struct CopyConfig {
-  StringRef OutputFilename;
-  StringRef InputFilename;
-  StringRef OutputFormat;
-  StringRef InputFormat;
-  StringRef BinaryArch;
-
-  StringRef SplitDWO;
-  StringRef AddGnuDebugLink;
-  std::vector<StringRef> ToRemove;
-  std::vector<StringRef> Keep;
-  std::vector<StringRef> OnlyKeep;
-  std::vector<StringRef> AddSection;
-  std::vector<StringRef> SymbolsToLocalize;
-  std::vector<StringRef> SymbolsToGlobalize;
-  std::vector<StringRef> SymbolsToWeaken;
-  std::vector<StringRef> SymbolsToRemove;
-  std::vector<StringRef> SymbolsToKeep;
-  StringMap<StringRef> SectionsToRename;
-  StringMap<StringRef> SymbolsToRename;
-  bool StripAll = false;
-  bool StripAllGNU = false;
-  bool StripDebug = false;
-  bool StripSections = false;
-  bool StripNonAlloc = false;
-  bool StripDWO = false;
-  bool StripUnneeded = false;
-  bool ExtractDWO = false;
-  bool LocalizeHidden = false;
-  bool Weaken = false;
-  bool DiscardAll = false;
-  bool OnlyKeepDebug = false;
-  bool KeepFileSymbols = false;
-};
-
 using SectionPred = std::function<bool(const SectionBase &Sec)>;
 
 } // namespace
@@ -211,17 +176,13 @@
   // Depending on the initial ELFT and OutputFormat we need a different Writer.
   switch (OutputElfType) {
   case ELFT_ELF32LE:
-    return llvm::make_unique<ELFWriter<ELF32LE>>(Obj, Buf,
-                                                 !Config.StripSections);
+    return llvm::make_unique<ELFWriter<ELF32LE>>(Obj, Buf, Config);
   case ELFT_ELF64LE:
-    return llvm::make_unique<ELFWriter<ELF64LE>>(Obj, Buf,
-                                                 !Config.StripSections);
+    return llvm::make_unique<ELFWriter<ELF64LE>>(Obj, Buf, Config);
   case ELFT_ELF32BE:
-    return llvm::make_unique<ELFWriter<ELF32BE>>(Obj, Buf,
-                                                 !Config.StripSections);
+    return llvm::make_unique<ELFWriter<ELF32BE>>(Obj, Buf, Config);
   case ELFT_ELF64BE:
-    return llvm::make_unique<ELFWriter<ELF64BE>>(Obj, Buf,
-                                                 !Config.StripSections);
+    return llvm::make_unique<ELFWriter<ELF64BE>>(Obj, Buf, Config);
   }
   llvm_unreachable("Invalid output format");
 }
@@ -587,6 +548,13 @@
   Config.OutputFormat = InputArgs.getLastArgValue(OBJCOPY_output_target);
   Config.BinaryArch = InputArgs.getLastArgValue(OBJCOPY_binary_architecture);
 
+  Config.CompressDebugSections =
+      StringSwitch<DebugCompressionType>(
+          InputArgs.getLastArgValue(OBJCOPY_compress_debug_sections))
+          .Case("zlib-gnu", DebugCompressionType::GNU)
+          .Case("zlib", DebugCompressionType::Z)
+          .Default(DebugCompressionType::None);
+
   Config.SplitDWO = InputArgs.getLastArgValue(OBJCOPY_split_dwo);
   Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);
 
@@ -627,6 +595,7 @@
   Config.DiscardAll = InputArgs.hasArg(OBJCOPY_discard_all);
   Config.OnlyKeepDebug = InputArgs.hasArg(OBJCOPY_only_keep_debug);
   Config.KeepFileSymbols = InputArgs.hasArg(OBJCOPY_keep_file_symbols);
+  Config.DecompressDebugSections = InputArgs.hasArg(OBJCOPY_decompress_debug_sections);
   for (auto Arg : InputArgs.filtered(OBJCOPY_localize_symbol))
     Config.SymbolsToLocalize.push_back(Arg->getValue());
   for (auto Arg : InputArgs.filtered(OBJCOPY_globalize_symbol))
@@ -638,6 +607,12 @@
   for (auto Arg : InputArgs.filtered(OBJCOPY_keep_symbol))
     Config.SymbolsToKeep.push_back(Arg->getValue());
 
+  if (Config.DecompressDebugSections &&
+      Config.CompressDebugSections != DebugCompressionType::None) {
+    error("Can not specify --compress-debug-sections as well as "
+          "--decompress-debug-sections at the same time.");
+  }
+
   return Config;
 }