Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -832,6 +832,20 @@
       }
       error(Twine("cannot find linker script ") + Arg->getValue());
       break;
+    // Handle a rarely-used, --just-symbols option.
+    //
+    // This option allows you to link your output against other existing
+    // program, so that if you load both the other program and your
+    // output to memory, your output can refer other program's symbols.
+    //
+    // What we are doing here is to read defined symbols from given ELF
+    // files and add them as absolute symbols.
+    case OPT_just_symbols: {
+      Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue());
+      if (Buffer.hasValue())
+        Files.push_back(createJustSymbolsFile(*Buffer));
+      break;
+    }
     case OPT_as_needed:
       Config->AsNeeded = true;
       break;
Index: ELF/InputFiles.h
===================================================================
--- ELF/InputFiles.h
+++ ELF/InputFiles.h
@@ -68,6 +68,7 @@
     ArchiveKind,
     BitcodeKind,
     BinaryKind,
+    JustSymbolsKind,
   };
 
   Kind kind() const { return FileKind; }
@@ -123,7 +124,7 @@
   ELFFileBase(Kind K, MemoryBufferRef M);
   static bool classof(const InputFile *F) {
     Kind K = F->kind();
-    return K == ObjKind || K == SharedKind;
+    return K == ObjKind || K == SharedKind || K == JustSymbolsKind;
   }
 
   llvm::object::ELFFile<ELFT> getObj() const {
@@ -328,9 +329,20 @@
   template <class ELFT> void parse();
 };
 
+template <class ELFT> class JustSymbolsFile : public ELFFileBase<ELFT> {
+public:
+  explicit JustSymbolsFile(MemoryBufferRef M)
+      : ELFFileBase<ELFT>(InputFile::JustSymbolsKind, M) {}
+  static bool classof(const InputFile *F) {
+    return F->kind() == InputFile::JustSymbolsKind;
+  }
+  void parse();
+};
+
 InputFile *createObjectFile(MemoryBufferRef MB, StringRef ArchiveName = "",
                             uint64_t OffsetInArchive = 0);
 InputFile *createSharedFile(MemoryBufferRef MB, StringRef DefaultSoName);
+InputFile *createJustSymbolsFile(MemoryBufferRef MB);
 
 extern std::vector<BinaryFile *> BinaryFiles;
 extern std::vector<BitcodeFile *> BitcodeFiles;
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -1007,6 +1007,38 @@
                            Data.size(), 0, STB_GLOBAL, nullptr, nullptr);
 }
 
+template <class ELFT> void JustSymbolsFile<ELFT>::parse() {
+  typedef typename ELFT::Shdr Elf_Shdr;
+  typedef typename ELFT::Sym Elf_Sym;
+  typedef typename ELFT::SymRange Elf_Sym_Range;
+
+  StringRef ObjName = this->getName();
+  ELFFile<ELFT> Obj = this->getObj();
+
+  if (Obj.getHeader()->e_type != ET_EXEC)
+    error(toString(this) + ": --just-symbols only accepts ET_EXEC files");
+
+  ArrayRef<Elf_Shdr> Sections = CHECK(Obj.sections(), ObjName);
+
+  for (const Elf_Shdr &Sec : Sections) {
+    if (Sec.sh_type != SHT_SYMTAB)
+      continue;
+
+    Elf_Sym_Range Syms = CHECK(Obj.symbols(&Sec), ObjName);
+    uint32_t FirstNonLocal = Sec.sh_info;
+    StringRef StringTable =
+        CHECK(Obj.getStringTableForSymtab(Sec, Sections), ObjName);
+
+    for (const Elf_Sym &Sym : Syms.slice(FirstNonLocal))
+      if (Sym.st_shndx != SHN_UNDEF) {
+        StringRef SymName = CHECK(Sym.getName(StringTable), ObjName);
+        Symtab->addRegular<ELFT>(SymName, Sym.st_other, Sym.getType(),
+                                 Sym.st_value, Sym.st_size, Sym.getBinding(),
+                                 nullptr, nullptr);
+      }
+  }
+}
+
 static bool isBitcode(MemoryBufferRef MB) {
   using namespace sys::fs;
   return identify_magic(MB.getBuffer()) == file_magic::bitcode;
@@ -1046,6 +1078,21 @@
   }
 }
 
+InputFile *elf::createJustSymbolsFile(MemoryBufferRef MB) {
+  switch (getELFKind(MB)) {
+  case ELF32LEKind:
+    return make<JustSymbolsFile<ELF32LE>>(MB);
+  case ELF32BEKind:
+    return make<JustSymbolsFile<ELF32BE>>(MB);
+  case ELF64LEKind:
+    return make<JustSymbolsFile<ELF64LE>>(MB);
+  case ELF64BEKind:
+    return make<JustSymbolsFile<ELF64BE>>(MB);
+  default:
+    llvm_unreachable("getELFKind");
+  }
+}
+
 MemoryBufferRef LazyObjFile::getBuffer() {
   if (Seen)
     return MemoryBufferRef();
@@ -1153,3 +1200,8 @@
 template void BinaryFile::parse<ELF32BE>();
 template void BinaryFile::parse<ELF64LE>();
 template void BinaryFile::parse<ELF64BE>();
+
+template class elf::JustSymbolsFile<ELF32LE>;
+template class elf::JustSymbolsFile<ELF32BE>;
+template class elf::JustSymbolsFile<ELF64LE>;
+template class elf::JustSymbolsFile<ELF64BE>;
Index: ELF/Options.td
===================================================================
--- ELF/Options.td
+++ ELF/Options.td
@@ -153,6 +153,8 @@
 defm init: Eq<"init">, HelpText<"Specify an initializer function">,
   MetaVarName<"<symbol>">;
 
+defm just_symbols: Eq<"just-symbols">, HelpText<"Just link symbols">;
+
 defm library: Eq<"library">, HelpText<"Root name of library to use">,
   MetaVarName<"<libName>">;
 
Index: ELF/SymbolTable.cpp
===================================================================
--- ELF/SymbolTable.cpp
+++ ELF/SymbolTable.cpp
@@ -74,6 +74,12 @@
     return;
   }
 
+  // --just-symbols file
+  if (auto *F = dyn_cast<JustSymbolsFile<ELFT>>(File)) {
+    F->parse();
+    return;
+  }
+
   // .a file
   if (auto *F = dyn_cast<ArchiveFile>(File)) {
     F->parse<ELFT>();
Index: test/ELF/Inputs/just-symbols.s
===================================================================
--- /dev/null
+++ test/ELF/Inputs/just-symbols.s
@@ -0,0 +1,9 @@
+.globl foo, bar
+foo:
+  ret
+
+.section .data
+.type bar, @object
+.size bar, 40
+bar:
+  .zero 40
Index: test/ELF/just-symbols.s
===================================================================
--- /dev/null
+++ test/ELF/just-symbols.s
@@ -0,0 +1,23 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %S/Inputs/just-symbols.s -o %t1
+# RUN: ld.lld %t1 -o %t1.exe -Ttext=0x10000 -Tdata=0x11000
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t2
+# RUN: ld.lld %t2 -just-symbols=%t1.exe -o %t2.exe
+# RUN: llvm-readelf -symbols %t2.exe | FileCheck %s
+#
+# RUN: ld.lld -just-symbols=%t1.exe -o %t3.exe
+# RUN: llvm-readelf -symbols %t3.exe | FileCheck %s
+
+# CHECK: 0000000000011000    40 OBJECT  GLOBAL DEFAULT  ABS bar
+# CHECK: 0000000000010000     0 NOTYPE  GLOBAL DEFAULT  ABS foo
+
+# RUN: not ld.lld -just-symbols=%t1 2>&1 | FileCheck %s --check-prefix CHECK-REL
+# CHECK-REL: error: {{.*}}: --just-symbols only accepts ET_EXEC files
+
+.globl _start
+_start:
+  call foo
+  call bar
+  ret