diff --git a/lld/MachO/Arch/X86_64.cpp b/lld/MachO/Arch/X86_64.cpp
--- a/lld/MachO/Arch/X86_64.cpp
+++ b/lld/MachO/Arch/X86_64.cpp
@@ -31,8 +31,10 @@
 
 uint64_t X86_64::getImplicitAddend(const uint8_t *loc, uint8_t type) const {
   switch (type) {
+  case X86_64_RELOC_BRANCH:
   case X86_64_RELOC_SIGNED:
   case X86_64_RELOC_GOT_LOAD:
+  case X86_64_RELOC_SIGNED_1:
     return read32le(loc);
   default:
     error("TODO: Unhandled relocation type " + std::to_string(type));
@@ -42,10 +44,14 @@
 
 void X86_64::relocateOne(uint8_t *loc, uint8_t type, uint64_t val) const {
   switch (type) {
+  case X86_64_RELOC_BRANCH:
   case X86_64_RELOC_SIGNED:
   case X86_64_RELOC_GOT_LOAD:
     // These types are only used for pc-relative relocations, so offset by 4
     // since the RIP has advanced by 4 at this point.
+  case X86_64_RELOC_SIGNED_1:
+    // This type is only used for pc-relative relocations, so offset by 4 since
+    // the RIP has advanced by 4 at this point.
     write32le(loc, val - 4);
     break;
   default:
diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -103,6 +103,12 @@
   MemoryBufferRef mbref = *buffer;
 
   switch (identify_magic(mbref.getBuffer())) {
+  case file_magic::archive: {
+    std::unique_ptr<object::Archive> file = CHECK(
+        object::Archive::create(mbref), path + ": failed to parse archive");
+    inputFiles.push_back(make<ArchiveFile>(file));
+    break;
+  }
   case file_magic::macho_object:
     inputFiles.push_back(make<ObjFile>(mbref));
     break;
@@ -160,7 +166,7 @@
 
   // Initialize InputSections.
   for (InputFile *file : inputFiles)
-    for (InputSection *sec : file->sections)
+    for (InputSection *sec : file->getInputSections())
       inputSections.push_back(sec);
 
   // Write to an output file.
diff --git a/lld/MachO/InputFiles.h b/lld/MachO/InputFiles.h
--- a/lld/MachO/InputFiles.h
+++ b/lld/MachO/InputFiles.h
@@ -28,15 +28,16 @@
   enum Kind {
     ObjKind,
     DylibKind,
+    ArchiveKind,
   };
 
   virtual ~InputFile() = default;
   Kind kind() const { return fileKind; }
   StringRef getName() const { return mb.getBufferIdentifier(); }
+  virtual std::vector<InputSection *> const getInputSections() = 0;
 
   MemoryBufferRef mb;
   std::vector<Symbol *> symbols;
-  std::vector<InputSection *> sections;
 
 protected:
   InputFile(Kind kind, MemoryBufferRef mb) : mb(mb), fileKind(kind) {}
@@ -55,6 +56,10 @@
 public:
   explicit ObjFile(MemoryBufferRef mb);
   static bool classof(const InputFile *f) { return f->kind() == ObjKind; }
+  std::vector<InputSection *> const getInputSections() { return sections; }
+
+private:
+  std::vector<InputSection *> sections;
 };
 
 // .dylib file
@@ -62,9 +67,26 @@
 public:
   explicit DylibFile(MemoryBufferRef mb);
   static bool classof(const InputFile *f) { return f->kind() == DylibKind; }
+  std::vector<InputSection *> const getInputSections() { return sections; }
 
   StringRef dylibName;
   uint64_t ordinal = 0; // Ordinal numbering starts from 1, so 0 is a sentinel
+
+private:
+  std::vector<InputSection *> sections;
+};
+
+// .a file
+class ArchiveFile : public InputFile {
+public:
+  explicit ArchiveFile(std::unique_ptr<llvm::object::Archive> &file);
+  static bool classof(const InputFile *f) { return f->kind() == ArchiveKind; }
+  std::vector<InputSection *> const getInputSections();
+  InputFile *fetch(const llvm::object::Archive::Symbol &sym);
+
+private:
+  llvm::DenseSet<uint64_t> seen;
+  std::vector<InputFile *> resolvedInputs;
 };
 
 extern std::vector<InputFile *> inputFiles;
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -239,6 +239,40 @@
   }
 }
 
+ArchiveFile::ArchiveFile(std::unique_ptr<llvm::object::Archive> &f)
+    : InputFile(ArchiveKind, f->getMemoryBufferRef()) {
+  for (const object::Archive::Symbol &sym : f->symbols())
+    symtab->addLazy(sym.getName(), this, sym);
+}
+
+std::vector<InputSection *> const ArchiveFile::getInputSections() {
+  std::vector<InputSection *> sections;
+  for (InputFile *input : resolvedInputs) {
+    auto inputSections = input->getInputSections();
+    sections.insert(sections.end(), inputSections.begin(), inputSections.end());
+  }
+  return sections;
+}
+
+InputFile *ArchiveFile::fetch(const object::Archive::Symbol &sym) {
+  object::Archive::Child c =
+      CHECK(sym.getMember(), toString(this) +
+                                 ": could not get the member for symbol " +
+                                 sym.getName());
+
+  if (!seen.insert(c.getChildOffset()).second)
+    return nullptr;
+
+  MemoryBufferRef mb =
+      CHECK(c.getMemoryBufferRef(),
+            toString(this) +
+                ": could not get the buffer for the member defining symbol " +
+                sym.getName());
+  auto file = make<ObjFile>(mb);
+  resolvedInputs.push_back(file);
+  return file;
+}
+
 // Returns "<internal>" or "baz.o".
 std::string lld::toString(const InputFile *file) {
   return file ? std::string(file->getName()) : "<internal>";
diff --git a/lld/MachO/SymbolTable.h b/lld/MachO/SymbolTable.h
--- a/lld/MachO/SymbolTable.h
+++ b/lld/MachO/SymbolTable.h
@@ -28,6 +28,8 @@
   Symbol *addUndefined(StringRef name);
 
   Symbol *addDylib(StringRef name, DylibFile *file);
+  Symbol *addLazy(StringRef name, ArchiveFile *file,
+                  const llvm::object::Archive::Symbol sym);
 
   ArrayRef<Symbol *> getSymbols() const { return symVector; }
   Symbol *find(StringRef name);
diff --git a/lld/MachO/SymbolTable.cpp b/lld/MachO/SymbolTable.cpp
--- a/lld/MachO/SymbolTable.cpp
+++ b/lld/MachO/SymbolTable.cpp
@@ -69,4 +69,17 @@
   return s;
 }
 
+Symbol *SymbolTable::addLazy(StringRef name, ArchiveFile *file,
+                             const llvm::object::Archive::Symbol sym) {
+  Symbol *s;
+  bool wasInserted;
+  std::tie(s, wasInserted) = insert(name);
+
+  if (wasInserted)
+    replaceSymbol<LazySymbol>(s, file, sym);
+  else if (isa<Undefined>(s))
+    file->fetch(sym);
+  return s;
+}
+
 SymbolTable *macho::symtab;
diff --git a/lld/MachO/Symbols.h b/lld/MachO/Symbols.h
--- a/lld/MachO/Symbols.h
+++ b/lld/MachO/Symbols.h
@@ -35,6 +35,7 @@
     DefinedKind,
     UndefinedKind,
     DylibKind,
+    LazyKind,
   };
 
   Kind kind() const { return static_cast<Kind>(symbolKind); }
@@ -79,6 +80,20 @@
   uint32_t gotIndex = UINT32_MAX;
 };
 
+class LazySymbol : public Symbol {
+public:
+  LazySymbol(InputFile *file, const llvm::object::Archive::Symbol sym)
+      : Symbol(LazyKind, sym.getName()), file(file), sym(sym) {}
+
+  static bool classof(const Symbol *s) { return s->kind() == LazyKind; }
+
+  InputFile *fetch();
+
+private:
+  InputFile *file;
+  const llvm::object::Archive::Symbol sym;
+};
+
 inline uint64_t Symbol::getVA() const {
   if (auto *d = dyn_cast<Defined>(this))
     return d->isec->getVA() + d->value - ImageBase;
@@ -89,6 +104,7 @@
   alignas(Defined) char a[sizeof(Defined)];
   alignas(Undefined) char b[sizeof(Undefined)];
   alignas(DylibSymbol) char c[sizeof(DylibSymbol)];
+  alignas(LazySymbol) char d[sizeof(LazySymbol)];
 };
 
 template <typename T, typename... ArgT>
diff --git a/lld/MachO/Symbols.cpp b/lld/MachO/Symbols.cpp
--- a/lld/MachO/Symbols.cpp
+++ b/lld/MachO/Symbols.cpp
@@ -15,6 +15,8 @@
 using namespace lld;
 using namespace lld::macho;
 
+InputFile *LazySymbol::fetch() { return cast<ArchiveFile>(file)->fetch(sym); }
+
 // Returns a symbol for an error message.
 std::string lld::toString(const Symbol &sym) {
   if (Optional<std::string> s = demangleItanium(sym.getName()))
diff --git a/lld/test/MachO/Inputs/archive.s b/lld/test/MachO/Inputs/archive.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/archive.s
@@ -0,0 +1,6 @@
+.global _main
+_main:
+  callq _boo
+  callq _bar
+  mov $0, %rax
+  ret
diff --git a/lld/test/MachO/Inputs/archive2.s b/lld/test/MachO/Inputs/archive2.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/archive2.s
@@ -0,0 +1,4 @@
+.global _boo
+_boo:
+  mov $2, %rax
+  ret
diff --git a/lld/test/MachO/Inputs/archive3.s b/lld/test/MachO/Inputs/archive3.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/archive3.s
@@ -0,0 +1,4 @@
+.global _bar
+_bar:
+  mov $3, %rax
+  ret
diff --git a/lld/test/MachO/Inputs/archive4.s b/lld/test/MachO/Inputs/archive4.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/archive4.s
@@ -0,0 +1,4 @@
+.global _lonely
+_alone:
+  mov $5, %rax
+  ret
diff --git a/lld/test/MachO/archive.s b/lld/test/MachO/archive.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/archive.s
@@ -0,0 +1,16 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %S/Inputs/archive.s -o %t.main
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %S/Inputs/archive2.s -o %t2
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %S/Inputs/archive3.s -o %t3
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %S/Inputs/archive4.s -o %t4
+
+# RUN: rm -f %t.a
+# RUN: llvm-ar rcs %t.a %t2 %t3 %t4
+
+# RUN: lld -flavor darwinnew %t.main %t.a -o %t.out
+# RUN: llvm-nm %t.out | FileCheck %s
+
+# CHECK:      T _bar
+# CHECK-NEXT: T _boo
+# CHECK-NEXT: T _main