Index: ELF/Driver.h
===================================================================
--- ELF/Driver.h
+++ ELF/Driver.h
@@ -20,9 +20,13 @@
 
 extern class LinkerDriver *Driver;
 
-// Entry point of the ELF linker.
+// An entry point of the ELF linker. It is not guranteed that the
+// function will return.
 void link(ArrayRef<const char *> Args);
 
+// The other entry point of the ELF linker which is guaranteed to return.
+bool main(llvm::ArrayRef<const char *> Args, raw_ostream &Diag);
+
 class LinkerDriver {
 public:
   void main(ArrayRef<const char *> Args);
Index: ELF/DriverUtils.cpp
===================================================================
--- ELF/DriverUtils.cpp
+++ ELF/DriverUtils.cpp
@@ -16,10 +16,19 @@
 #include "Driver.h"
 #include "Error.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Config/config.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/Program.h"
 #include "llvm/Support/StringSaver.h"
+#include "llvm/Support/raw_ostream.h"
+
+#ifdef HAVE_UNISTD_H
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#endif
 
 using namespace llvm;
 
@@ -118,3 +127,100 @@
     sys::path::append(Path, Dir, File);
   return Path.str();
 }
+
+#ifdef LLVM_ON_UNIX
+
+// This is a wrapper for link(). Unlike link(), this function always returns.
+bool elf2::main(ArrayRef<const char *> Args, raw_ostream &Diag) {
+  // Create a communication channel between this process and a child.
+  int Fd[2];
+  pipe(Fd);
+
+  // Start a subprocess.
+  pid_t P;
+  if ((P = fork()) == -1)
+    error("fork failed.");
+
+  if (P == 0) {
+    // We are in the child. Plumb stdout and stderr to the pipe.
+    close(Fd[0]);
+    close(0);
+    dup2(Fd[1], 1);
+    dup2(Fd[1], 2);
+    link(Args);
+    exit(0);
+  }
+
+  // We are in the parent. Read from the pipe until EOF.
+  close(Fd[1]);
+  char Buf[4096];
+  for (;;) {
+    size_t N = read(Fd[0], Buf, sizeof(Buf));
+    if (N == size_t(-1)) {
+      if (errno == EAGAIN)
+        continue;
+      error("read failed.");
+    }
+    if (N == 0)
+      break;
+    Diag << StringRef(Buf, N);
+  }
+
+  // Return true if the child exited normally.
+  for (;;) {
+    int Status;
+    if (waitpid(P, &Status, 0) == -1)
+      error("waitpid failed.");
+    if (WIFEXITED(Status))
+      return !WEXITSTATUS(Status);
+  }
+}
+
+#else
+
+// Windows version of main(). Because fork is not available on Windows,
+// we start a new process.
+bool elf2::main(ArrayRef<const char *> Args, raw_ostream &Diag) {
+  if (Args.size() < 2) {
+    link(Args);
+    exit(0);
+  }
+
+  // "-lld-no-exec" is the marker that we are in a subprocess.
+  if (Args[1] == StringRef("-lld-no-exec")) {
+    std::vector<const char *> Argv(Args.begin(), Args.end());
+    Argv.erase(Argv.begin() + 1);
+    link(Argv);
+    exit(0);
+  }
+
+  // We want to build arguments such that lld -flavor gnu Args[1]...
+  // First, look for lld.exe from the current executable directory or
+  // from %PATH%.
+  SmallString<128> Dir = sys::fs::getMainExecutable(nullptr, nullptr);
+  sys::path::remove_filename(Dir);
+  ErrorOr<std::string> Exe = sys::findProgramByName("lld.exe", {Dir});
+  if (!Exe) {
+    Exe = sys::findProgramByName("lld.exe");
+    if (!Exe)
+      error("lld is not found");
+  }
+
+  // Add other parameters.
+  std::vector<const char *> Argv;
+  Argv.push_back(Exe->data());
+  Argv.push_back("-flavor");
+  Argv.push_back("gnu");
+  Argv.push_back("-lld-no-exec");
+  Argv.insert(Argv.end(), Args.begin() + 1, Args.end());
+  Argv.push_back(nullptr);
+
+  // Start a subprocess and return its result.
+  std::string ErrMsg;
+  int Status = sys::ExecuteAndWait(Argv[0], Argv.data(), nullptr, nullptr, 0, 0,
+                                   &ErrMsg);
+  Diag << ErrMsg;
+  return !Status;
+}
+
+#endif
Index: include/lld/Driver/Driver.h
===================================================================
--- include/lld/Driver/Driver.h
+++ include/lld/Driver/Driver.h
@@ -125,7 +125,12 @@
 }
 
 namespace elf2 {
+// An entry point for the internal use. It is not guaranteed to return.
 void link(llvm::ArrayRef<const char *> args);
+
+// If you want to call LLD ELF's main from your program, use this function.
+// It is guaranteed to return. Returns true on success.
+bool main(llvm::ArrayRef<const char *> args, raw_ostream &diag = llvm::errs());
 }
 
 /// Driver for lld unit tests