Index: ELF/Config.h
===================================================================
--- ELF/Config.h
+++ ELF/Config.h
@@ -41,6 +41,7 @@
   std::string RPath;
   std::vector<llvm::StringRef> SearchPaths;
   bool AllowMultipleDefinition;
+  bool AsNeeded = false;
   bool DiscardAll;
   bool DiscardLocals;
   bool DiscardNone;
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -94,9 +94,12 @@
     }
     Files.push_back(make_unique<ArchiveFile>(MBRef));
     return;
-  case file_magic::elf_shared_object:
-    Files.push_back(createELFFile<SharedFile>(MBRef));
+  case file_magic::elf_shared_object: {
+    std::unique_ptr<ELFFileBase> File = createELFFile<SharedFile>(MBRef);
+    cast<SharedFileBase>(File.get())->AsNeeded = Config->AsNeeded;
+    Files.push_back(std::move(File));
     return;
+  }
   default:
     Files.push_back(createELFFile<ObjectFile>(MBRef));
   }
@@ -181,6 +184,12 @@
     case OPT_script:
       addFile(Arg->getValue());
       break;
+    case OPT_as_needed:
+      Config->AsNeeded = true;
+      break;
+    case OPT_no_as_needed:
+      Config->AsNeeded = false;
+      break;
     case OPT_Bstatic:
       Config->Static = true;
       break;
Index: ELF/InputFiles.h
===================================================================
--- ELF/InputFiles.h
+++ ELF/InputFiles.h
@@ -146,7 +146,7 @@
     uint32_t FirstNonLocal = this->Symtab->sh_info;
     if (SymbolIndex < FirstNonLocal)
       return nullptr;
-    return SymbolBodies[SymbolIndex - FirstNonLocal]->repl();
+    return SymbolBodies[SymbolIndex - FirstNonLocal];
   }
 
   Elf_Sym_Range getLocalSymbols();
@@ -198,6 +198,11 @@
   StringRef getSoName() const { return SoName; }
   virtual void parseSoName() = 0;
   virtual void parse() = 0;
+
+  // Used for --as-needed
+  bool AsNeeded = false;
+  bool IsUsed = false;
+  bool isNeeded() const { return !AsNeeded || IsUsed; }
 };
 
 template <class ELFT>
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -329,7 +329,7 @@
     error(NameOrErr.getError());
     StringRef Name = *NameOrErr;
 
-    SymbolBodies.emplace_back(Name, Sym);
+    SymbolBodies.emplace_back(this, Name, Sym);
   }
 }
 
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -46,7 +46,7 @@
         continue;
       SymVA = getLocalSymVA(Sym, File);
     } else {
-      SymbolBody &Body = *File.getSymbolBody(SymIndex);
+      SymbolBody &Body = *File.getSymbolBody(SymIndex)->repl();
       SymVA = getSymVA<ELFT>(Body);
       if (Target->relocNeedsPlt(Type, Body)) {
         SymVA = Out<ELFT>::Plt->getEntryAddr(Body);
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -155,12 +155,15 @@
 
 void LinkerScript::readAsNeeded() {
   expect("(");
+  bool Orig = Config->AsNeeded;
+  Config->AsNeeded = true;
   for (;;) {
     StringRef Tok = next();
     if (Tok == ")")
-      return;
+      break;
     addFile(Tok);
   }
+  Config->AsNeeded = Orig;
 }
 
 void LinkerScript::readEntry() {
Index: ELF/Options.td
===================================================================
--- ELF/Options.td
+++ ELF/Options.td
@@ -14,6 +14,8 @@
 
 def allow_shlib_undefined : Flag<["--", "-"], "allow-shlib-undefined">;
 
+def as_needed : Flag<["--"], "as-needed">;
+
 def disable_new_dtags : Flag<["--"], "disable-new-dtags">,
   HelpText<"Disable new dynamic tags">;
 
@@ -52,6 +54,8 @@
 
 def no_allow_shlib_undefined : Flag<["--"], "no-allow-shlib-undefined">;
 
+def no_as_needed : Flag<["--"], "no-as-needed">;
+
 def no_whole_archive : Flag<["--"], "no-whole-archive">,
   HelpText<"Restores the default behavior of loading archive members">;
 
@@ -111,14 +115,12 @@
 
 // Options listed below are silently ignored now.
 def O3 : Flag<["-"], "O3">;
-def as_needed : Flag<["--"], "as-needed">;
 def build_id : Flag<["--"], "build-id">;
 def eh_frame_hdr : Flag<["--"], "eh-frame-hdr">;
 def end_group : Flag<["--"], "end-group">;
 def gc_sections : Flag<["--"], "gc-sections">;
 def hash_style : Joined<["--"], "hash-style=">;
 def no_add_needed : Flag<["--"], "no-add-needed">;
-def no_as_needed : Flag<["--"], "no-as-needed">;
 def no_fatal_warnings : Flag<["--"], "no-fatal-warnings">;
 def start_group : Flag<["--"], "start-group">;
 def strip_all : Flag<["--"], "strip-all">;
Index: ELF/OutputSections.cpp
===================================================================
--- ELF/OutputSections.cpp
+++ ELF/OutputSections.cpp
@@ -116,8 +116,10 @@
     OutputSection<ELFT> *OutSec = C.getOutputSection();
     uint32_t SymIndex = RI.getSymbol(IsMips64EL);
     const ObjectFile<ELFT> &File = *C.getFile();
-    const SymbolBody *Body = File.getSymbolBody(SymIndex);
+    SymbolBody *Body = File.getSymbolBody(SymIndex);
     const ELFFile<ELFT> &Obj = File.getObj();
+    if (Body)
+      Body = Body->repl();
 
     uint32_t Type = RI.getType(IsMips64EL);
 
@@ -279,6 +281,8 @@
     NumEntries += 2;
 
   for (const std::unique_ptr<SharedFile<ELFT>> &F : SymTab.getSharedFiles()) {
+    if (!F->isNeeded())
+      continue;
     Out<ELFT>::DynStrTab->add(F->getSoName());
     ++NumEntries;
   }
@@ -356,7 +360,8 @@
   WriteArray(DT_FINI_ARRAY, DT_FINI_ARRAYSZ, FiniArraySec);
 
   for (const std::unique_ptr<SharedFile<ELFT>> &F : SymTab.getSharedFiles())
-    WriteVal(DT_NEEDED, Out<ELFT>::DynStrTab->getFileOff(F->getSoName()));
+    if (F->isNeeded())
+      WriteVal(DT_NEEDED, Out<ELFT>::DynStrTab->getFileOff(F->getSoName()));
 
   if (InitSym)
     WritePtr(DT_INIT, getSymVA<ELFT>(*InitSym));
Index: ELF/Symbols.h
===================================================================
--- ELF/Symbols.h
+++ ELF/Symbols.h
@@ -24,6 +24,7 @@
 class SymbolBody;
 template <class ELFT> class ObjectFile;
 template <class ELFT> class OutputSection;
+template <class ELFT> class SharedFile;
 
 // Initializes global objects defined in this file.
 // Called at the beginning of main().
@@ -263,8 +264,10 @@
     return S->kind() == Base::SharedKind;
   }
 
-  SharedSymbol(StringRef Name, const Elf_Sym &Sym)
-      : Defined<ELFT>(Base::SharedKind, Name, Sym) {}
+  SharedSymbol(SharedFile<ELFT> *F, StringRef Name, const Elf_Sym &Sym)
+      : Defined<ELFT>(Base::SharedKind, Name, Sym), File(F) {}
+
+  SharedFile<ELFT> *File;
 };
 
 // This class represents a symbol defined in an archive file. It is
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -174,6 +174,14 @@
     uint32_t SymIndex = RI.getSymbol(IsMips64EL);
     SymbolBody *Body = File.getSymbolBody(SymIndex);
     uint32_t Type = RI.getType(IsMips64EL);
+
+    // Set "used" bit for --as-needed.
+    if (Body && Body->isUndefined() && !Body->isWeak())
+      if (auto *S = dyn_cast<SharedSymbol<ELFT>>(Body->repl()))
+        S->File->IsUsed = true;
+
+    if (Body)
+      Body = Body->repl();
     if (Body) {
       if (Target->relocNeedsPlt(Type, *Body)) {
         if (Body->isInPlt())
@@ -186,12 +194,13 @@
         Out<ELFT>::Got->addEntry(Body);
       }
     }
-    if (canBePreempted(Body)) {
+
+    bool CBP = canBePreempted(Body);
+    if (!CBP && (!Config->Shared || Target->isRelRelative(Type)))
+      continue;
+    if (CBP)
       Body->setUsedInDynamicReloc();
-      Out<ELFT>::RelaDyn->addReloc({C, RI});
-    } else if (Config->Shared && !Target->isRelRelative(Type)) {
-      Out<ELFT>::RelaDyn->addReloc({C, RI});
-    }
+    Out<ELFT>::RelaDyn->addReloc({C, RI});
   }
 }
 
Index: test/elf2/Inputs/shared2.s
===================================================================
--- /dev/null
+++ test/elf2/Inputs/shared2.s
@@ -0,0 +1,6 @@
+.global bar2
+.type bar2, @function
+bar2:
+
+.global zed2
+zed2:
Index: test/elf2/as-needed.s
===================================================================
--- /dev/null
+++ test/elf2/as-needed.s
@@ -0,0 +1,34 @@
+// REQUIRES: x86
+// RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %s -o %t.o
+// RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %p/Inputs/shared.s -o %t2.o
+// RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %p/Inputs/shared2.s -o %t3.o
+// RUN: ld.lld2 -shared %t2.o -soname shared1 -o %t2.so
+// RUN: ld.lld2 -shared %t3.o -soname shared2 -o %t3.so
+
+// RUN: ld.lld2 %t.o %t2.so %t3.so -o %t2
+// RUN: llvm-readobj -dynamic-table %t2 | FileCheck %s
+
+// RUN: ld.lld2 --as-needed %t.o %t2.so %t3.so -o %t2
+// RUN: llvm-readobj -dynamic-table %t2 | FileCheck -check-prefix=CHECK2 %s
+
+// RUN: ld.lld2 --as-needed %t.o %t2.so --no-as-needed %t3.so -o %t2
+// RUN: llvm-readobj -dynamic-table %t2 | FileCheck %s
+
+// RUN: echo "GROUP(" %t2.so %t3.so ")" > %t.script
+// RUN: ld.lld2 %t.o %t.script -o %t2
+// RUN: llvm-readobj -dynamic-table %t2 | FileCheck %s
+
+// RUN: echo "GROUP(AS_NEEDED(" %t2.so %t3.so "))" > %t.script
+// RUN: ld.lld2 %t.o %t.script -o %t2
+// RUN: llvm-readobj -dynamic-table %t2 | FileCheck -check-prefix=CHECK2 %s
+
+// CHECK: NEEDED SharedLibrary (shared1)
+// CHECK: NEEDED SharedLibrary (shared2)
+
+// CHECK2:     NEEDED SharedLibrary (shared1)
+// CHECK2-NOT: NEEDED SharedLibrary (shared2)
+
+.global _start
+_start:
+.long bar
+.long zed