Index: llvm/test/tools/llvm-objcopy/ELF/only-keep-debug.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-objcopy/ELF/only-keep-debug.test
@@ -0,0 +1,50 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-objcopy --only-keep-debug %t %t.dbg
+# RUN: llvm-readobj --sections %t.dbg | FileCheck %s
+# RUN: llvm-readobj --sections %t.dbg | FileCheck --check-prefix=NOTE %s
+# RUN: llvm-readobj --sections %t.dbg | FileCheck --check-prefix=DEBUG %s
+
+!ELF
+FileHeader:
+  Class:     ELFCLASS64
+  Data:      ELFDATA2LSB
+  Type:      ET_REL
+  Machine:   EM_X86_64
+Sections:
+  - Name:    .text
+    Type:    SHT_PROGBITS
+    Flags:   [ SHF_ALLOC, SHF_EXECINSTR ]
+    Content: "c3c3c3c3"
+  - Name:    .note
+    Type:    SHT_NOTE
+    Flags:   [ SHF_ALLOC ]
+    Content: 040000001000000003000000474E55004FCB712AA6387724A9F465A32CD8C14B
+  - Name:    .debug
+    Type:    SHT_PROGBITS
+    Content: "031F"
+
+## Checks that alloc segment is marked no bits.
+## It has no contents but size should stay the same.
+# CHECK:       Index: 1
+# CHECK-NEXT:  Name: .text
+# CHECK-NEXT:  Type: SHT_NOBITS
+# CHECK-NEXT:  Flags [ (0x6)
+# CHECK-NEXT:   SHF_ALLOC (0x2)
+# CHECK-NEXT:   SHF_EXECINSTR (0x4)
+# CHECK-NEXT:  ]
+# CHECK-NEXT:  Address:
+# CHECK-NEXT:  Offset:
+# CHECK-NEXT:  Size: 64
+
+## SHT_NOTE does not change.
+# NOTE:        Index: 2
+# NOTE-NEXT:   Name: .note
+# NOTE-NEXT:   Type: SHT_NOTE
+# NOTE-NEXT:   Flags [ (0x2)
+# NOTE-NEXT:    SHF_ALLOC (0x2)
+
+## .debug sections should never change.
+# DEBUG:       Index: 3
+# DEBUG-NEXT:  Name: .debug
+# DEBUG-NEXT:  Type: SHT_PROGBITS
+# DEBUG-NEXT:  Flags [ (0x0)
Index: llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
===================================================================
--- llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -579,7 +579,23 @@
           return &Obj.addSection<DecompressedSection>(*CS);
         });
 
-  return Obj.removeSections(Config.AllowBrokenLinks, RemovePred);
+  if (Error E = Obj.removeSections(Config.AllowBrokenLinks, RemovePred))
+    return E;
+
+  if (Config.OnlyKeepDebug) {
+    for (auto &Sec : Obj.sections()) {
+      if (Sec.Flags & (SHF_ALLOC | SHF_GROUP) && Sec.Type != SHT_NOTE) {
+        if (Sec.Type == SHT_SYMTAB) {
+          Sec.Flags &= ~SHF_ALLOC;
+          continue;
+        }
+        Sec.Type = SHT_NOBITS;
+        Sec.clearSectionContents();
+      }
+    }
+  }
+
+  return Error::success();
 }
 
 // This function handles the high level operations of GNU objcopy including
Index: llvm/tools/llvm-objcopy/ELF/Object.h
===================================================================
--- llvm/tools/llvm-objcopy/ELF/Object.h
+++ llvm/tools/llvm-objcopy/ELF/Object.h
@@ -417,6 +417,7 @@
   virtual void markSymbols();
   virtual void
   replaceSectionReferences(const DenseMap<SectionBase *, SectionBase *> &);
+  virtual void clearSectionContents();
 };
 
 class Segment {
@@ -479,6 +480,7 @@
       function_ref<bool(const SectionBase *)> ToRemove) override;
   void initialize(SectionTableRef SecTable) override;
   void finalize() override;
+  void clearSectionContents() override;
 };
 
 class OwnedDataSection : public SectionBase {
@@ -507,6 +509,7 @@
   void appendHexData(StringRef HexData);
   void accept(SectionVisitor &Sec) const override;
   void accept(MutableSectionVisitor &Visitor) override;
+  void clearSectionContents() override;
 };
 
 class CompressedSection : public SectionBase {
Index: llvm/tools/llvm-objcopy/ELF/Object.cpp
===================================================================
--- llvm/tools/llvm-objcopy/ELF/Object.cpp
+++ llvm/tools/llvm-objcopy/ELF/Object.cpp
@@ -81,6 +81,10 @@
   Shdr.sh_entsize = Sec.EntrySize;
 }
 
+void SectionBase::clearSectionContents() {
+  assert(0 && "Cannot clear this sections contents");
+}
+
 template <class ELFT> void ELFSectionSizer<ELFT>::visit(Section &Sec) {}
 
 template <class ELFT>
@@ -468,6 +472,10 @@
   Size = Data.size();
 }
 
+void OwnedDataSection::clearSectionContents() {
+  Data.clear();
+}
+
 void BinarySectionWriter::visit(const CompressedSection &Sec) {
   error("cannot write compressed section '" + Sec.Name + "' ");
 }
@@ -997,6 +1005,10 @@
 
 void Section::finalize() { this->Link = LinkSection ? LinkSection->Index : 0; }
 
+void Section::clearSectionContents() {
+  this->Contents = ArrayRef<uint8_t>();
+}
+
 void GnuDebugLinkSection::init(StringRef File) {
   FileName = sys::path::filename(File);
   // The format for the .gnu_debuglink starts with the file name and is