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
@@ -32,6 +32,7 @@
 uint64_t X86_64::getImplicitAddend(const uint8_t *loc, uint8_t type) const {
   switch (type) {
   case X86_64_RELOC_SIGNED:
+  case X86_64_RELOC_GOT_LOAD:
     return read32le(loc);
   default:
     error("TODO: Unhandled relocation type " + std::to_string(type));
@@ -42,8 +43,9 @@
 void X86_64::relocateOne(uint8_t *loc, uint8_t type, uint64_t val) const {
   switch (type) {
   case X86_64_RELOC_SIGNED:
-    // This type is only used for pc-relative relocations, so offset by 4 since
-    // the RIP has advanced by 4 at this point.
+  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.
     write32le(loc, val - 4);
     break;
   default:
diff --git a/lld/MachO/CMakeLists.txt b/lld/MachO/CMakeLists.txt
--- a/lld/MachO/CMakeLists.txt
+++ b/lld/MachO/CMakeLists.txt
@@ -10,6 +10,7 @@
   OutputSegment.cpp
   SymbolTable.cpp
   Symbols.cpp
+  SyntheticSections.cpp
   Target.cpp
   Writer.cpp
 
diff --git a/lld/MachO/Config.h b/lld/MachO/Config.h
--- a/lld/MachO/Config.h
+++ b/lld/MachO/Config.h
@@ -11,6 +11,8 @@
 
 #include "llvm/ADT/StringRef.h"
 
+#include <vector>
+
 namespace lld {
 namespace macho {
 
@@ -19,6 +21,8 @@
 struct Configuration {
   llvm::StringRef outputFile;
   Symbol *entry;
+
+  std::vector<llvm::StringRef> searchPaths;
 };
 
 extern Configuration *config;
diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -68,6 +68,17 @@
   return args;
 }
 
+// This is for -lfoo. We'll look for libfoo.dylib from search paths.
+static Optional<std::string> findDylib(StringRef name) {
+  for (StringRef dir : config->searchPaths) {
+    std::string path = (dir + "/lib" + name + ".dylib").str();
+    if (fs::exists(path))
+      return path;
+  }
+  error("library not found for -l" + name);
+  return None;
+}
+
 static TargetInfo *createTargetInfo(opt::InputArgList &args) {
   StringRef s = args.getLastArgValue(OPT_arch, "x86_64");
   if (s != "x86_64")
@@ -75,6 +86,15 @@
   return createX86_64TargetInfo();
 }
 
+static std::vector<StringRef> getSearchPaths(opt::InputArgList &args) {
+  std::vector<StringRef> ret;
+  if (!args.hasArg(OPT_Z))
+    ret = {"/usr/lib", "/usr/local/lib"};
+  for (StringRef s : args::getStrings(args, OPT_L))
+    ret.push_back(s);
+  return ret;
+}
+
 static void addFile(StringRef path) {
   Optional<MemoryBufferRef> buffer = readFile(path);
   if (!buffer)
@@ -83,7 +103,10 @@
 
   switch (identify_magic(mbref.getBuffer())) {
   case file_magic::macho_object:
-    inputFiles.push_back(make<ObjFile>(mbref));
+    inputFiles.push_back(make<ObjFile>(path, mbref));
+    break;
+  case file_magic::macho_dynamically_linked_shared_lib:
+    inputFiles.push_back(make<DylibFile>(path, mbref));
     break;
   default:
     error(path + ": unhandled file type");
@@ -110,15 +133,21 @@
 
   config->entry = symtab->addUndefined(args.getLastArgValue(OPT_e, "_main"));
   config->outputFile = args.getLastArgValue(OPT_o, "a.out");
+  config->searchPaths = getSearchPaths(args);
 
   getOrCreateOutputSegment("__TEXT", VM_PROT_READ | VM_PROT_EXECUTE);
   getOrCreateOutputSegment("__DATA", VM_PROT_READ | VM_PROT_WRITE);
+  getOrCreateOutputSegment("__DATA_CONST", VM_PROT_READ | VM_PROT_WRITE);
 
   for (opt::Arg *arg : args) {
     switch (arg->getOption().getID()) {
     case OPT_INPUT:
       addFile(arg->getValue());
       break;
+    case OPT_l:
+      if (Optional<std::string> path = findDylib(arg->getValue()))
+        addFile(*path);
+      break;
     }
   }
 
@@ -127,6 +156,8 @@
     return false;
   }
 
+  createSyntheticSections();
+
   // Initialize InputSections.
   for (InputFile *file : inputFiles)
     for (InputSection *sec : file->sections)
@@ -136,6 +167,7 @@
   for (InputSection *isec : inputSections) {
     OutputSegment *os =
         getOrCreateOutputSegment(isec->segname, VM_PROT_READ | VM_PROT_WRITE);
+    isec->parent = os;
     os->sections[isec->name].push_back(isec);
   }
 
diff --git a/lld/MachO/InputFiles.h b/lld/MachO/InputFiles.h
--- a/lld/MachO/InputFiles.h
+++ b/lld/MachO/InputFiles.h
@@ -27,20 +27,21 @@
 public:
   enum Kind {
     ObjKind,
+    DylibKind,
   };
 
   virtual ~InputFile() = default;
-
   Kind kind() const { return fileKind; }
   StringRef getName() const { return mb.getBufferIdentifier(); }
 
+  StringRef path;
   MemoryBufferRef mb;
   std::vector<Symbol *> symbols;
   std::vector<InputSection *> sections;
-  StringRef dylibName;
 
 protected:
-  InputFile(Kind kind, MemoryBufferRef mb) : mb(mb), fileKind(kind) {}
+  InputFile(Kind kind, StringRef path, MemoryBufferRef mb)
+      : path(path), mb(mb), fileKind(kind) {}
 
   std::vector<InputSection *> parseSections(ArrayRef<llvm::MachO::section_64>);
 
@@ -54,10 +55,20 @@
 // .o file
 class ObjFile : public InputFile {
 public:
-  explicit ObjFile(MemoryBufferRef mb);
+  explicit ObjFile(StringRef path, MemoryBufferRef mb);
   static bool classof(const InputFile *f) { return f->kind() == ObjKind; }
 };
 
+// .dylib file
+class DylibFile : public InputFile {
+public:
+  explicit DylibFile(StringRef path, MemoryBufferRef mb);
+  static bool classof(const InputFile *f) { return f->kind() == DylibKind; }
+
+  StringRef dylibName;
+  uint64_t ordinal = 0; // Ordinal numbering starts from 1, so 0 is a sentinel
+};
+
 extern std::vector<InputFile *> inputFiles;
 
 llvm::Optional<MemoryBufferRef> readFile(StringRef path);
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -74,7 +74,15 @@
   std::unique_ptr<MemoryBuffer> &mb = *mbOrErr;
   MemoryBufferRef mbref = mb->getMemBufferRef();
   make<std::unique_ptr<MemoryBuffer>>(std::move(mb)); // take mb ownership
-  return mbref;
+
+  // If this is a regular non-fat file, return it.
+  const char *buf = mbref.getBufferStart();
+  auto *hdr = reinterpret_cast<const MachO::fat_header *>(buf);
+  if (read32be(&hdr->magic) != MachO::FAT_MAGIC)
+    return mbref;
+
+  error("TODO: Add support for universal binaries");
+  return None;
 }
 
 static const load_command *findCommand(const mach_header_64 *hdr,
@@ -143,7 +151,8 @@
   }
 }
 
-ObjFile::ObjFile(MemoryBufferRef mb) : InputFile(ObjKind, mb) {
+ObjFile::ObjFile(StringRef path, MemoryBufferRef mb)
+    : InputFile(ObjKind, path, mb) {
   auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
   auto *hdr = reinterpret_cast<const mach_header_64 *>(mb.getBufferStart());
   ArrayRef<section_64> objSections;
@@ -168,7 +177,7 @@
 
       // Undefined symbol
       if (!sym.n_sect) {
-        error("TODO: Support undefined symbols");
+        symbols.push_back(symtab->addUndefined(name));
         continue;
       }
 
@@ -198,6 +207,34 @@
   }
 }
 
+DylibFile::DylibFile(StringRef path, MemoryBufferRef mb)
+    : InputFile(DylibKind, path, mb) {
+  auto *buf = (const uint8_t *)mb.getBufferStart();
+  auto *hdr = (const mach_header_64 *)mb.getBufferStart();
+
+  if (const load_command *cmd = findCommand(hdr, LC_ID_DYLIB)) {
+    auto *c = (const dylib_command *)cmd;
+    dylibName = (const char *)cmd + read32le(&c->dylib.name);
+  } else {
+    error("dylib " + path + " missing LC_ID_DYLIB load command");
+    return;
+  }
+
+  if (const load_command *cmd = findCommand(hdr, LC_SYMTAB)) {
+    auto *c = (const symtab_command *)cmd;
+    const char *strtab = (const char *)buf + c->stroff;
+    ArrayRef<const nlist_64> nList((const nlist_64 *)(buf + c->symoff),
+                                   c->nsyms);
+
+    symbols.reserve(c->nsyms);
+
+    for (const nlist_64 &sym : nList) {
+      StringRef name = strtab + sym.n_strx;
+      symbols.push_back(symtab->addDylib(name, this));
+    }
+  }
+}
+
 // Returns "<internal>" or "baz.o".
 std::string lld::toString(const InputFile *file) {
   return file ? std::string(file->getName()) : "<internal>";
diff --git a/lld/MachO/InputSection.h b/lld/MachO/InputSection.h
--- a/lld/MachO/InputSection.h
+++ b/lld/MachO/InputSection.h
@@ -19,6 +19,7 @@
 
 class InputFile;
 class InputSection;
+class OutputSegment;
 class Symbol;
 
 struct Reloc {
@@ -30,9 +31,12 @@
 
 class InputSection {
 public:
-  void writeTo(uint8_t *buf);
+  virtual ~InputSection() = default;
+  virtual void writeTo(uint8_t *buf);
+  virtual size_t getSize() const { return data.size(); }
 
   InputFile *file = nullptr;
+  OutputSegment *parent = nullptr;
   StringRef name;
   StringRef segname;
 
diff --git a/lld/MachO/InputSection.cpp b/lld/MachO/InputSection.cpp
--- a/lld/MachO/InputSection.cpp
+++ b/lld/MachO/InputSection.cpp
@@ -8,6 +8,7 @@
 
 #include "InputSection.h"
 #include "Symbols.h"
+#include "SyntheticSections.h"
 #include "Target.h"
 #include "lld/Common/Memory.h"
 #include "llvm/Support/Endian.h"
@@ -24,9 +25,13 @@
 
   for (Reloc &r : relocs) {
     uint64_t va = 0;
-    if (auto *s = r.target.dyn_cast<Symbol *>())
-      va = s->getVA();
-    else if (auto *isec = r.target.dyn_cast<InputSection *>())
+    if (auto *s = r.target.dyn_cast<Symbol *>()) {
+      if (auto *dylibSymbol = dyn_cast<DylibSymbol>(s)) {
+        va = in.got->addr - ImageBase + dylibSymbol->gotIndex * WordSize;
+      } else {
+        va = s->getVA();
+      }
+    } else if (auto *isec = r.target.dyn_cast<InputSection *>())
       va = isec->addr;
     else
       llvm_unreachable("Unknown relocation target");
diff --git a/lld/MachO/Options.td b/lld/MachO/Options.td
--- a/lld/MachO/Options.td
+++ b/lld/MachO/Options.td
@@ -1,10 +1,19 @@
 include "llvm/Option/OptParser.td"
 
+def L: JoinedOrSeparate<["-"], "L">, MetaVarName<"<dir>">,
+  HelpText<"Add directory to library search path">;
+
+def Z: Flag<["-"], "Z">,
+  HelpText<"Do not add standard directories to library search path">;
+
 def arch: Separate<["-"], "arch">, MetaVarName<"<arch-name>">,
   HelpText<"Architecture to link">;
 
 def e: Separate<["-"], "e">, HelpText<"Name of entry point symbol">;
 
+def l: Joined<["-"], "l">, MetaVarName<"<libname>">,
+  HelpText<"Base name of library searched for in -L directories">;
+
 def o: Separate<["-"], "o">, MetaVarName<"<path>">,
   HelpText<"Path to file to write output">;
 
diff --git a/lld/MachO/OutputSegment.h b/lld/MachO/OutputSegment.h
--- a/lld/MachO/OutputSegment.h
+++ b/lld/MachO/OutputSegment.h
@@ -19,8 +19,13 @@
 
 class OutputSegment {
 public:
+  InputSection *firstSection() const { return sections.front().second.at(0); }
+
+  InputSection *lastSection() const { return sections.back().second.back(); }
+
   StringRef name;
   uint32_t perms;
+  uint8_t index;
   llvm::MapVector<StringRef, std::vector<InputSection *>> sections;
 };
 
diff --git a/lld/MachO/SymbolTable.h b/lld/MachO/SymbolTable.h
--- a/lld/MachO/SymbolTable.h
+++ b/lld/MachO/SymbolTable.h
@@ -16,9 +16,9 @@
 namespace lld {
 namespace macho {
 
-class InputFile;
-class InputSection;
 class ArchiveFile;
+class DylibFile;
+class InputSection;
 class Symbol;
 
 class SymbolTable {
@@ -27,6 +27,8 @@
 
   Symbol *addUndefined(StringRef name);
 
+  Symbol *addDylib(StringRef name, DylibFile *file);
+
   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
@@ -59,4 +59,14 @@
   return s;
 }
 
+Symbol *SymbolTable::addDylib(StringRef name, DylibFile *file) {
+  Symbol *s;
+  bool wasInserted;
+  std::tie(s, wasInserted) = insert(name);
+
+  if (wasInserted)
+    replaceSymbol<DylibSymbol>(s, file, name);
+  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
@@ -18,7 +18,7 @@
 namespace macho {
 
 class InputSection;
-class InputFile;
+class DylibFile;
 class ArchiveFile;
 
 struct StringRefZ {
@@ -34,6 +34,7 @@
   enum Kind {
     DefinedKind,
     UndefinedKind,
+    DylibKind,
   };
 
   Kind kind() const { return static_cast<Kind>(symbolKind); }
@@ -42,11 +43,8 @@
 
   uint64_t getVA() const;
 
-  InputFile *file;
-
 protected:
-  Symbol(Kind k, InputFile *file, StringRefZ name)
-      : file(file), symbolKind(k), name(name) {}
+  Symbol(Kind k, StringRefZ name) : symbolKind(k), name(name) {}
 
   Kind symbolKind;
   StringRefZ name;
@@ -55,7 +53,7 @@
 class Defined : public Symbol {
 public:
   Defined(StringRefZ name, InputSection *isec, uint32_t value)
-      : Symbol(DefinedKind, nullptr, name), isec(isec), value(value) {}
+      : Symbol(DefinedKind, name), isec(isec), value(value) {}
 
   InputSection *isec;
   uint32_t value;
@@ -65,11 +63,22 @@
 
 class Undefined : public Symbol {
 public:
-  Undefined(StringRefZ name) : Symbol(UndefinedKind, nullptr, name) {}
+  Undefined(StringRefZ name) : Symbol(UndefinedKind, name) {}
 
   static bool classof(const Symbol *s) { return s->kind() == UndefinedKind; }
 };
 
+class DylibSymbol : public Symbol {
+public:
+  DylibSymbol(DylibFile *file, StringRefZ name)
+      : Symbol(DylibKind, name), file(file) {}
+
+  static bool classof(const Symbol *s) { return s->kind() == DylibKind; }
+
+  DylibFile *file;
+  uint64_t gotIndex = UINT64_MAX;
+};
+
 inline uint64_t Symbol::getVA() const {
   if (auto *d = dyn_cast<Defined>(this))
     return d->isec->addr + d->value - ImageBase;
@@ -79,6 +88,7 @@
 union SymbolUnion {
   alignas(Defined) char a[sizeof(Defined)];
   alignas(Undefined) char b[sizeof(Undefined)];
+  alignas(DylibSymbol) char c[sizeof(DylibSymbol)];
 };
 
 template <typename T, typename... ArgT>
diff --git a/lld/MachO/SyntheticSections.h b/lld/MachO/SyntheticSections.h
new file mode 100644
--- /dev/null
+++ b/lld/MachO/SyntheticSections.h
@@ -0,0 +1,48 @@
+//===- SyntheticSections.h -------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_MACHO_SYNTHETIC_SECTIONS_H
+#define LLD_MACHO_SYNTHETIC_SECTIONS_H
+
+#include "InputSection.h"
+#include "Target.h"
+#include "llvm/ADT/SetVector.h"
+
+namespace lld {
+namespace macho {
+
+class DylibSymbol;
+
+class GotSection : public InputSection {
+public:
+  GotSection();
+
+  void addEntry(DylibSymbol &sym);
+  const llvm::SetVector<const DylibSymbol *>& getEntries() const {
+    return entries;
+  }
+
+  size_t getSize() const override { return entries.size() * WordSize; }
+
+  void writeTo(uint8_t *buf) override {
+    // Nothing to write, GOT starts as all zeroes
+  }
+private:
+  llvm::SetVector<const DylibSymbol *> entries;
+};
+
+struct InStruct {
+  GotSection *got;
+};
+
+extern InStruct in;
+
+} // namespace macho
+} // namespace lld
+
+#endif
diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
new file mode 100644
--- /dev/null
+++ b/lld/MachO/SyntheticSections.cpp
@@ -0,0 +1,36 @@
+//===- SyntheticSections.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "SyntheticSections.h"
+#include "Symbols.h"
+
+using namespace llvm::MachO;
+
+namespace lld {
+namespace macho {
+
+GotSection::GotSection() {
+  segname = "__DATA_CONST";
+  name = "__got";
+  align = 8;
+  flags = S_NON_LAZY_SYMBOL_POINTERS;
+
+  // TODO: section_64::reserved1 should be an index into the indirect symbol
+  // table, which we do not currently emit
+}
+
+void GotSection::addEntry(DylibSymbol &sym) {
+  if (entries.insert(&sym)) {
+    sym.gotIndex = entries.size() - 1;
+  }
+}
+
+InStruct in;
+
+} // namespace macho
+} // namespace lld
diff --git a/lld/MachO/Target.h b/lld/MachO/Target.h
--- a/lld/MachO/Target.h
+++ b/lld/MachO/Target.h
@@ -15,6 +15,7 @@
 namespace macho {
 
 enum {
+  WordSize = 8,
   PageSize = 4096,
   ImageBase = 4096,
   MaxAlignmentPowerOf2 = 32,
diff --git a/lld/MachO/Writer.h b/lld/MachO/Writer.h
--- a/lld/MachO/Writer.h
+++ b/lld/MachO/Writer.h
@@ -14,6 +14,8 @@
 
 void writeResult();
 
+void createSyntheticSections();
+
 } // namespace macho
 } // namespace lld
 
diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -13,11 +13,13 @@
 #include "OutputSegment.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
+#include "SyntheticSections.h"
 #include "Target.h"
 
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Memory.h"
 #include "llvm/BinaryFormat/MachO.h"
+#include "llvm/Support/EndianStream.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/MathExtras.h"
 
@@ -44,8 +46,11 @@
   Writer() : buffer(errorHandler().outputBuffer) {}
 
   void createLoadCommands();
+  void scanRelocations();
   void assignAddresses();
 
+  void createDyldInfoContents();
+
   void openFile();
   void writeHeader();
   void writeSections();
@@ -83,8 +88,9 @@
     c->cmd = LC_SEGMENT_64;
     c->cmdsize = getSize();
     strcpy(c->segname, "__LINKEDIT");
+    c->vmaddr = addr;
     c->fileoff = fileOff;
-    c->filesize = contents.size();
+    c->filesize = c->vmsize = contents.size();
     c->maxprot = VM_PROT_READ | VM_PROT_WRITE;
     c->initprot = VM_PROT_READ;
   }
@@ -92,6 +98,7 @@
   uint64_t getOffset() const { return fileOff + contents.size(); }
 
   uint64_t fileOff = 0;
+  uint64_t addr = 0;
   SmallVector<char, 128> contents;
 };
 
@@ -103,10 +110,14 @@
     auto *c = reinterpret_cast<dyld_info_command *>(buf);
     c->cmd = LC_DYLD_INFO_ONLY;
     c->cmdsize = getSize();
+    c->bind_off = bindOff;
+    c->bind_size = bindSize;
     c->export_off = exportOff;
     c->export_size = exportSize;
   }
 
+  uint64_t bindOff = 0;
+  uint64_t bindSize = 0;
   uint64_t exportOff = 0;
   uint64_t exportSize = 0;
 };
@@ -139,16 +150,14 @@
     c->cmdsize = getSize();
     memcpy(c->segname, name.data(), name.size());
 
-    InputSection *firstSec = seg->sections.front().second[0];
-    InputSection *lastSec = seg->sections.back().second.back();
-
     // dyld3's MachOLoaded::getSlide() assumes that the __TEXT segment starts
     // from the beginning of the file (i.e. the header).
     // TODO: replace this logic by creating a synthetic __TEXT,__mach_header
     // section instead.
-    c->fileoff = name == "__TEXT" ? 0 : firstSec->addr - ImageBase;
+    c->fileoff = name == "__TEXT" ? 0 : seg->firstSection()->addr - ImageBase;
     c->vmaddr = c->fileoff + ImageBase;
-    c->vmsize = c->filesize = lastSec->addr + lastSec->data.size() - c->vmaddr;
+    c->vmsize = c->filesize =
+        seg->lastSection()->addr + seg->lastSection()->getSize() - c->vmaddr;
     c->maxprot = VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
     c->initprot = seg->perms;
     c->nsects = seg->sections.size();
@@ -171,7 +180,7 @@
         maxAlign = std::max(maxAlign, section->align);
       sectHdr->align = Log2_32(maxAlign);
       sectHdr->flags = sections[0]->flags;
-      sectHdr->size = sections.back()->addr + sections.back()->data.size() -
+      sectHdr->size = sections.back()->addr + sections.back()->getSize() -
                       sections[0]->addr;
     }
   }
@@ -265,13 +274,33 @@
   loadCommands.push_back(make<LCLoadDylinker>());
   loadCommands.push_back(make<LCDysymtab>());
   loadCommands.push_back(make<LCMain>());
-  // TODO: dyld requires libSystem to be loaded. libSystem is a universal
-  // binary and we don't have support for that yet, so mock it out here.
-  loadCommands.push_back(make<LCLoadDylib>("/usr/lib/libSystem.B.dylib"));
 
-  for (OutputSegment *seg : outputSegments)
-    if (!seg->sections.empty())
+  uint8_t segIndex = 2; // LCPagezero and LCLinkEdit are segment load commands
+  for (OutputSegment *seg : outputSegments) {
+    if (!seg->sections.empty()) {
       loadCommands.push_back(make<LCSegment>(seg->name, seg));
+      seg->index = segIndex++;
+    }
+  }
+
+  uint64_t dylibOrdinal = 1;
+  for (InputFile *file : inputFiles) {
+    if (auto dylibFile = dyn_cast<DylibFile>(file)) {
+      loadCommands.push_back(make<LCLoadDylib>(dylibFile->dylibName));
+      dylibFile->ordinal = dylibOrdinal++;
+    }
+  }
+}
+
+void Writer::scanRelocations() {
+  for (auto &sect : inputSections) {
+    for (Reloc &r : sect->relocs) {
+      if (auto *s = r.target.dyn_cast<Symbol *>()) {
+        if (auto dylibSymbol = dyn_cast<DylibSymbol>(s))
+          in.got->addEntry(*dylibSymbol);
+      }
+    }
+  }
 }
 
 void Writer::assignAddresses() {
@@ -291,14 +320,52 @@
       for (InputSection *isec : sections) {
         addr = alignTo(addr, isec->align);
         isec->addr = addr;
-        addr += isec->data.size();
+        addr += isec->getSize();
       }
     }
   }
 
+  addr = alignTo(addr, PageSize);
+  linkEditSeg->addr = addr;
   linkEditSeg->fileOff = addr - ImageBase;
 }
 
+// LC_DYLD_INFO_ONLY contains symbol import/export information. Imported
+// symbols are described by a sequence of bind opcodes, which allow for a
+// compact encoding. Exported symbols are described using a trie.
+void Writer::createDyldInfoContents() {
+  uint64_t sectionStart = linkEditSeg->getOffset();
+  raw_svector_ostream os{linkEditSeg->contents};
+
+  // Emit bind opcodes, which tell dyld which dylib symbols to load.
+
+  // Tell dyld to write to the section containing the GOT.
+  os << (char)(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB | in.got->parent->index);
+  encodeULEB128(in.got->addr - in.got->parent->firstSection()->addr, os);
+  for (const DylibSymbol *sym : in.got->getEntries()) {
+    // TODO: Implement compact encoding -- we only need to encode the
+    // differences between consecutive symbol entries.
+    if (sym->file->ordinal <= BIND_IMMEDIATE_MASK) {
+      os << (char)(BIND_OPCODE_SET_DYLIB_ORDINAL_IMM | sym->file->ordinal);
+    } else {
+      error("TODO: Support larger dylib symbol ordinals");
+      continue;
+    }
+    os << (char)BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM;
+    os << sym->getName() << '\0';
+    os << (char)(BIND_OPCODE_SET_TYPE_IMM | BIND_TYPE_POINTER);
+    os << (char)BIND_OPCODE_DO_BIND;
+  }
+
+  // TODO: emit bind opcodes for lazy symbols.
+  os << (char)BIND_OPCODE_DONE;
+
+  dyldInfoSeg->bindOff = sectionStart;
+  dyldInfoSeg->bindSize = linkEditSeg->getOffset() - sectionStart;
+
+  // TODO: Implement symbol export trie.
+}
+
 void Writer::openFile() {
   Expected<std::unique_ptr<FileOutputBuffer>> bufferOrErr =
       FileOutputBuffer::create(config->outputFile, fileSize,
@@ -342,7 +409,11 @@
 
 void Writer::run() {
   createLoadCommands();
+  scanRelocations();
   assignAddresses();
+
+  // Fill __LINKEDIT contents
+  createDyldInfoContents();
   fileSize = linkEditSeg->fileOff + linkEditSeg->contents.size();
 
   openFile();
@@ -357,3 +428,8 @@
 }
 
 void macho::writeResult() { Writer().run(); }
+
+void macho::createSyntheticSections() {
+  in.got = make<GotSection>();
+  inputSections.push_back(in.got);
+}
diff --git a/lld/test/MachO/Inputs/goodbye-dylib.yaml b/lld/test/MachO/Inputs/goodbye-dylib.yaml
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/goodbye-dylib.yaml
@@ -0,0 +1,175 @@
+## This yaml file was originally generated from linking the following source
+## input with ld64:
+##
+## .section __TEXT,__cstring
+## .globl _goodbye_world
+##
+## _goodbye_world:
+## .asciz "Goodbye world!\n"
+##
+## When lld can produce dylibs, we will use that instead for our test setup.
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000006
+  ncmds:           11
+  sizeofcmds:      624
+  flags:           0x00100085
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         232
+    segname:         __TEXT
+    vmaddr:          0
+    vmsize:          4096
+    fileoff:         0
+    filesize:        4096
+    maxprot:         5
+    initprot:        5
+    nsects:          2
+    flags:           0
+    Sections:
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+        segname:         __TEXT
+        addr:            0x0000000000000FF0
+        size:            0
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+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+        content:         ''
+      - sectname:        __cstring
+        segname:         __TEXT
+        addr:            0x0000000000000FF0
+        size:            16
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+        align:           0
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+    cmdsize:         64
+    dylib:
+      name:            24
+      timestamp:       1
+      current_version: 0
+      compatibility_version: 0
+    PayloadString:   '@executable_path/libgoodbye.dylib'
+    ZeroPadBytes:    7
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+    cmdsize:         16
+    dataoff:         4120
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+  - cmd:             LC_DATA_IN_CODE
+    cmdsize:         16
+    dataoff:         4128
+    datasize:        0
+LinkEditData:
+  ExportTrie:
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+    - _goodbye_world
+    - ''
+    - ''
+    - ''
+    - ''
+    - ''
+    - ''
+    - ''
+...
diff --git a/lld/test/MachO/Inputs/hello-dylib.yaml b/lld/test/MachO/Inputs/hello-dylib.yaml
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/hello-dylib.yaml
@@ -0,0 +1,169 @@
+## This yaml file was originally generated from linking the following source
+## input with ld64:
+##
+## .section __TEXT,__cstring
+## .globl _hello_world
+##
+## _hello_world:
+## .asciz "Hello world!\n"
+##
+## When lld can produce dylibs, we will use that instead for our test setup.
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000006
+  ncmds:           11
+  sizeofcmds:      616
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+    cmdsize:         56
+    dylib:
+      name:            24
+      timestamp:       1
+      current_version: 0
+      compatibility_version: 0
+    PayloadString:   '@executable_path/libhello.dylib'
+    ZeroPadBytes:    1
+  - cmd:             LC_DYLD_INFO_ONLY
+    cmdsize:         48
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+    rebase_size:     0
+    bind_off:        0
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+    export_size:     24
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+    sdk:             659200
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+        version:         34734080
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+    cmdsize:         16
+    version:         0
+  - cmd:             LC_FUNCTION_STARTS
+    cmdsize:         16
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+    datasize:        8
+  - cmd:             LC_DATA_IN_CODE
+    cmdsize:         16
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+        Flags:           0x0000000000000000
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+        ImportName:      ''
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+    - ' '
+    - _hello_world
+    - ''
+...
diff --git a/lld/test/MachO/Inputs/no-id-dylib.yaml b/lld/test/MachO/Inputs/no-id-dylib.yaml
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/Inputs/no-id-dylib.yaml
@@ -0,0 +1,160 @@
+## This yaml file was originally generated from linking the following source
+## input with ld64:
+##
+## .section __TEXT,__cstring
+## .globl _hello_world
+##
+## _hello_world:
+## .asciz "Hello world!\n"
+##
+## Then we deleted the LC_ID_DYLIB command from the YAML file.
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000006
+  ncmds:           10
+  sizeofcmds:      616
+  flags:           0x00100085
+  reserved:        0x00000000
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+        reserved3:       0x00000000
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+        segname:         __TEXT
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+    fileoff:         4096
+    filesize:        64
+    maxprot:         1
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+    flags:           0
+  - cmd:             LC_DYLD_INFO_ONLY
+    cmdsize:         48
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+    rebase_size:     0
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+    export_size:     24
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+    cmdsize:         16
+    dataoff:         4128
+    datasize:        0
+LinkEditData:
+  ExportTrie:
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+  StringTable:
+    - ' '
+    - _hello_world
+    - ''
+...
diff --git a/lld/test/MachO/dylink.s b/lld/test/MachO/dylink.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/dylink.s
@@ -0,0 +1,41 @@
+# REQUIRES: x86
+# RUN: mkdir -p %t
+# RUN: yaml2obj %p/Inputs/hello-dylib.yaml -o %t/libhello.dylib
+# RUN: yaml2obj %p/Inputs/goodbye-dylib.yaml -o %t/libgoodbye.dylib
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/dylink.o
+# RUN: lld -flavor darwinnew -o %t/dylink -Z -L%t -lhello -lgoodbye %t/dylink.o
+# RUN: (obj2yaml %t/dylink; llvm-objdump -d %t/dylink) | FileCheck %s
+
+# CHECK:      sectname: __got
+# CHECK-NEXT: segname: __DATA_CONST
+# CHECK-NEXT: addr: 0x[[#%X, GOT:]]
+# CHECK:      Opcode: BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM
+# CHECK-NEXT: Imm: 0
+# CHECK-NEXT: Symbol: _goodbye_world
+# CHECK:      Opcode: BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM
+# CHECK-NEXT: Imm: 0
+# CHECK-NEXT: Symbol: _hello_world
+
+# CHECK: movq [[#%u,HELLO_OFF:]](%rip), %rsi
+# CHECK-NEXT: [[#%x, GOT - HELLO_OFF + 8]]:
+
+# CHECK: movq [[#%u,GOODBYE_OFF:]](%rip), %rsi
+# CHECK-NEXT: [[#%x, GOT - GOODBYE_OFF]]:
+
+.section __TEXT,__text
+.globl _main
+
+_main:
+  movl $0x2000004, %eax # write() syscall
+  mov $1, %rdi # stdout
+  movq _hello_world@GOTPCREL(%rip), %rsi
+  mov $13, %rdx # length of str
+  syscall
+
+  movl $0x2000004, %eax # write() syscall
+  mov $1, %rdi # stdout
+  movq _goodbye_world@GOTPCREL(%rip), %rsi
+  mov $15, %rdx # length of str
+  syscall
+  mov $0, %rax
+  ret
diff --git a/lld/test/MachO/missing-dylib.s b/lld/test/MachO/missing-dylib.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/missing-dylib.s
@@ -0,0 +1,5 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
+# RUN: not lld -flavor darwinnew -Z -o %t -lmissing %t.o 2>&1 | FileCheck %s
+
+# CHECK: library not found for -lmissing
diff --git a/lld/test/MachO/no-id-dylink.s b/lld/test/MachO/no-id-dylink.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/no-id-dylink.s
@@ -0,0 +1,13 @@
+# REQUIRES: x86
+# RUN: mkdir -p %t
+# RUN: yaml2obj %p/Inputs/no-id-dylib.yaml -o %t/libnoid.dylib
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/no-id-dylink.o
+# RUN: not lld -flavor darwinnew -o %t/no-id-dylink -Z -L%t -lnoid %t/no-id-dylink.o 2>&1 | FileCheck %s
+# CHECK: dylib {{.*}}libnoid.dylib missing LC_ID_DYLIB load command
+
+.text
+.globl _main
+
+_main:
+  mov $0, %rax
+  ret