Index: lld/trunk/ELF/Config.h
===================================================================
--- lld/trunk/ELF/Config.h
+++ lld/trunk/ELF/Config.h
@@ -69,6 +69,7 @@
   bool NoinhibitExec;
   bool PrintGcSections;
   bool Relocatable;
+  bool SaveTemps;
   bool Shared;
   bool Static = false;
   bool StripAll;
Index: lld/trunk/ELF/Driver.cpp
===================================================================
--- lld/trunk/ELF/Driver.cpp
+++ lld/trunk/ELF/Driver.cpp
@@ -239,6 +239,7 @@
   Config->NoinhibitExec = Args.hasArg(OPT_noinhibit_exec);
   Config->PrintGcSections = Args.hasArg(OPT_print_gc_sections);
   Config->Relocatable = Args.hasArg(OPT_relocatable);
+  Config->SaveTemps = Args.hasArg(OPT_save_temps);
   Config->Shared = Args.hasArg(OPT_shared);
   Config->StripAll = Args.hasArg(OPT_strip_all);
   Config->Verbose = Args.hasArg(OPT_verbose);
Index: lld/trunk/ELF/Options.td
===================================================================
--- lld/trunk/ELF/Options.td
+++ lld/trunk/ELF/Options.td
@@ -182,3 +182,6 @@
 
 // Aliases for ignored options
 def alias_version_script_version_script : Joined<["--"], "version-script=">, Alias<version_script>;
+
+// Debugging options
+def save_temps : Flag<["-"], "save-temps">;
Index: lld/trunk/ELF/SymbolTable.cpp
===================================================================
--- lld/trunk/ELF/SymbolTable.cpp
+++ lld/trunk/ELF/SymbolTable.cpp
@@ -147,6 +147,13 @@
   Mover.move(std::move(M), Keep, [](GlobalValue &, IRMover::ValueAdder) {});
 }
 
+static void saveBCFile(std::string Path, Module &M) {
+  std::error_code EC;
+  raw_fd_ostream OS(Path, EC, sys::fs::OpenFlags::F_None);
+  check(EC);
+  WriteBitcodeToFile(&M, OS, /* ShouldPreserveUseListOrder */ true);
+}
+
 // Merge all the bitcode files we have seen, codegen the result and return
 // the resulting ObjectFile.
 template <class ELFT>
@@ -156,6 +163,8 @@
   IRMover Mover(Combined);
   for (const std::unique_ptr<BitcodeFile> &F : BitcodeFiles)
     addBitcodeFile(Mover, *F, Context);
+  if (Config->SaveTemps)
+    saveBCFile(Config->OutputFile.str() + ".lto.bc", Combined);
   std::unique_ptr<InputFile> F = codegen(Combined);
   ObjectFiles.emplace_back(cast<ObjectFile<ELFT>>(F.release()));
   return &*ObjectFiles.back();
Index: lld/trunk/test/ELF/lto/Inputs/save-temps.ll
===================================================================
--- lld/trunk/test/ELF/lto/Inputs/save-temps.ll
+++ lld/trunk/test/ELF/lto/Inputs/save-temps.ll
@@ -0,0 +1,6 @@
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @bar() {
+  ret void
+}
Index: lld/trunk/test/ELF/lto/save-temps.ll
===================================================================
--- lld/trunk/test/ELF/lto/save-temps.ll
+++ lld/trunk/test/ELF/lto/save-temps.ll
@@ -0,0 +1,17 @@
+; REQUIRES: x86
+; RUN: rm -f %t.so %t.so.lto.bc
+; RUN: llvm-as %s -o %t.o
+; RUN: llvm-as %p/Inputs/save-temps.ll -o %t2.o
+; RUN: ld.lld -shared -m elf_x86_64 %t.o %t2.o -o %t.so -save-temps
+; RUN: llvm-nm %t.so | FileCheck %s
+; RUN: llvm-nm %t.so.lto.bc | FileCheck %s
+
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @foo() {
+  ret void
+}
+
+; CHECK-DAG: T bar
+; CHECK-DAG: T foo