Index: llvm/trunk/test/tools/gold/X86/Inputs/cache.ll
===================================================================
--- llvm/trunk/test/tools/gold/X86/Inputs/cache.ll
+++ llvm/trunk/test/tools/gold/X86/Inputs/cache.ll
@@ -0,0 +1,9 @@
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @main() {
+entry:
+  call void (...) @globalfunc()
+  ret i32 0
+}
+
+declare void @globalfunc(...)
Index: llvm/trunk/test/tools/gold/X86/cache.ll
===================================================================
--- llvm/trunk/test/tools/gold/X86/cache.ll
+++ llvm/trunk/test/tools/gold/X86/cache.ll
@@ -0,0 +1,18 @@
+; RUN: opt -module-summary %s -o %t.o
+; RUN: opt -module-summary %p/Inputs/cache.ll -o %t2.o
+
+; Verify that enabling caching is working
+; RUN: rm -Rf %t.cache && mkdir %t.cache
+; RUN: %gold -m elf_x86_64 -plugin %llvmshlibdir/LLVMgold.so \
+; RUN:     --plugin-opt=thinlto \
+; RUN:     --plugin-opt=cache-dir=%t.cache \
+; RUN:     -o %t3.o %t2.o %t.o
+
+; RUN: ls %t.cache | count 2
+
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @globalfunc() #0 {
+entry:
+  ret void
+}
Index: llvm/trunk/tools/gold/gold-plugin.cpp
===================================================================
--- llvm/trunk/tools/gold/gold-plugin.cpp
+++ llvm/trunk/tools/gold/gold-plugin.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/LTO/Caching.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ManagedStatic.h"
@@ -161,6 +162,8 @@
   // corresponding bitcode file, will use a path formed by replacing the
   // bitcode file's path prefix matching oldprefix with newprefix.
   static std::string thinlto_prefix_replace;
+  // Optional path to a directory for caching ThinLTO objects.
+  static std::string cache_dir;
   // Additional options to pass into the code generator.
   // Note: This array will contain all plugin options which are not claimed
   // as plugin exclusive to pass to the code generator.
@@ -199,6 +202,8 @@
       thinlto_prefix_replace = opt.substr(strlen("thinlto-prefix-replace="));
       if (thinlto_prefix_replace.find(";") == std::string::npos)
         message(LDPL_FATAL, "thinlto-prefix-replace expects 'old;new' format");
+    } else if (opt.startswith("cache-dir=")) {
+      cache_dir = opt.substr(strlen("cache-dir="));
     } else if (opt.size() == 2 && opt[0] == 'O') {
       if (opt[1] < '0' || opt[1] > '3')
         message(LDPL_FATAL, "Optimization level must be between 0 and 3");
@@ -792,12 +797,19 @@
   std::vector<uintptr_t> IsTemporary(MaxTasks);
   std::vector<SmallString<128>> Filenames(MaxTasks);
 
-  auto AddOutput = [&](size_t Task) {
+  auto AddOutput =
+      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectOutput> {
     auto &OutputName = Filenames[Task];
     getOutputFileName(Filename, /*TempOutFile=*/!SaveTemps, OutputName,
                       MaxTasks > 1 ? Task : -1);
     IsTemporary[Task] = !SaveTemps;
-    return llvm::make_unique<LTOOutput>(OutputName);
+    if (options::cache_dir.empty())
+      return llvm::make_unique<LTOOutput>(OutputName);
+
+    return llvm::make_unique<CacheObjectOutput>(
+        options::cache_dir, [OutputName](std::unique_ptr<MemoryBuffer> Buffer) {
+          *LTOOutput(OutputName).getStream() << Buffer->getBuffer();
+        });
   };
 
   check(Lto->run(AddOutput));