Index: ELF/Config.h
===================================================================
--- ELF/Config.h
+++ ELF/Config.h
@@ -83,6 +83,7 @@
   llvm::StringRef LtoNewPmPasses;
   llvm::StringRef OutputFile;
   llvm::StringRef SoName;
+  llvm::StringRef Startup;
   llvm::StringRef Sysroot;
   std::string RPath;
   std::vector<VersionDefinition> VersionDefinitions;
Index: ELF/Driver.h
===================================================================
--- ELF/Driver.h
+++ ELF/Driver.h
@@ -37,6 +37,7 @@
   void readConfigs(llvm::opt::InputArgList &Args);
   void createFiles(llvm::opt::InputArgList &Args);
   void inferMachineType();
+  void reorderFiles();
   template <class ELFT> void link(llvm::opt::InputArgList &Args);
 
   // True if we are in --whole-archive and --no-whole-archive.
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -691,6 +691,24 @@
   error("target emulation unknown: -m or at least one .o file required");
 }
 
+// This is for linker script STARTUP command. If STARTUP(foo.o) is
+// specified, LLD reorders input files so that foo.o becomes the first
+// object file to be linked, assuming that the file's .text section
+// will become the executable's entry address.
+void LinkerDriver::reorderFiles() {
+  if (Config->Startup.empty())
+    return;
+  for (auto I = Files.begin(), E = Files.end(); I != E; ++I) {
+    InputFile *F = *I;
+    if (F->getName() != Config->Startup)
+      continue;
+    Files.erase(I);
+    Files.insert(Files.begin(), F);
+    return;
+  }
+  warn(Config->Startup + ": STARTUP file not found");
+}
+
 // Parses -image-base option.
 static uint64_t getImageBase(opt::InputArgList &Args) {
   // Use default if no -image-base option is given.
@@ -743,6 +761,9 @@
   if (!isPowerOf2_64(Config->MaxPageSize))
     error("max-page-size: value isn't a power of 2");
 
+  // Process linker script STARTUP command.
+  reorderFiles();
+
   // Add all files to the symbol table. After this, the symbol table
   // contains all known names except a few linker-synthesized symbols.
   for (InputFile *F : Files)
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -973,6 +973,7 @@
   void readPhdrs();
   void readSearchDir();
   void readSections();
+  void readStartup();
   void readVersion();
   void readVersionScriptCommand();
 
@@ -1069,6 +1070,8 @@
       readSearchDir();
     } else if (Tok == "SECTIONS") {
       readSections();
+    } else if (Tok == "STARTUP") {
+      readStartup();
     } else if (Tok == "VERSION") {
       readVersion();
     } else if (SymbolAssignment *Cmd = readProvideOrAssignment(Tok)) {
@@ -1243,6 +1246,8 @@
   }
 }
 
+void ScriptParser::readStartup() { Config->Startup = readParenLiteral(); }
+
 static int precedence(StringRef Op) {
   return StringSwitch<int>(Op)
       .Cases("*", "/", 5)
Index: test/ELF/linkerscript/startup.s
===================================================================
--- /dev/null
+++ test/ELF/linkerscript/startup.s
@@ -0,0 +1,29 @@
+# REQUIRES: x86
+
+# RUN: mkdir -p %t.dir
+# RUN: cd %t.dir
+
+# RUN: echo ".quad 0xAAAAAAAAAAAAAAAA" > %t1.s
+# RUN: echo ".quad 0xFFFFFFFFFFFFFFFF" > %t2.s
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %t1.s -o foo.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %t2.s -o bar.o
+
+# RUN: echo "STARTUP(foo.o)" > script
+# RUN: ld.lld -o exe -script=script foo.o bar.o
+# RUN: llvm-objdump -s exe | FileCheck -check-prefix=FOO %s
+
+# FOO: Contents of section .text:
+# FOO: 201000 aaaaaaaa aaaaaaaa ffffffff ffffffff
+
+# RUN: echo "STARTUP(bar.o)" > script
+# RUN: ld.lld -o exe -script=script foo.o bar.o
+# RUN: llvm-objdump -s exe | FileCheck -check-prefix=BAR %s
+
+# BAR: Contents of section .text:
+# BAR: 201000 ffffffff ffffffff aaaaaaaa aaaaaaaa
+
+# RUN: echo "STARTUP(nosuchfile)" > script
+# RUN: ld.lld -o exe -script=script foo.o bar.o 2>&1 \
+# RUN:   | FileCheck -check-prefix=WARN %s
+
+# WARN: nosuchfile: STARTUP file not found