Index: lld/trunk/ELF/Config.h
===================================================================
--- lld/trunk/ELF/Config.h
+++ lld/trunk/ELF/Config.h
@@ -96,6 +96,7 @@
   llvm::StringRef Sysroot;
   llvm::StringRef ThinLTOCacheDir;
   llvm::StringRef ThinLTOIndexOnlyArg;
+  std::pair<llvm::StringRef, llvm::StringRef> ThinLTOObjectSuffixReplace;
   std::pair<llvm::StringRef, llvm::StringRef> ThinLTOPrefixReplace;
   std::string Rpath;
   std::vector<VersionDefinition> VersionDefinitions;
Index: lld/trunk/ELF/Driver.cpp
===================================================================
--- lld/trunk/ELF/Driver.cpp
+++ lld/trunk/ELF/Driver.cpp
@@ -813,6 +813,14 @@
       if (Config->ThinLTOPrefixReplace.second.empty())
         error("thinlto-prefix-replace expects 'old;new' format, but got " +
               S.substr(23));
+    } else if (S.startswith("thinlto-object-suffix-replace=")) {
+      std::tie(Config->ThinLTOObjectSuffixReplace.first,
+               Config->ThinLTOObjectSuffixReplace.second) =
+          S.substr(30).split(';');
+      if (Config->ThinLTOObjectSuffixReplace.second.empty())
+        error(
+            "thinlto-object-suffix-replace expects 'old;new' format, but got " +
+            S.substr(30));
     } else if (!S.startswith("/") && !S.startswith("-fresolution=") &&
                !S.startswith("-pass-through=") && !S.startswith("thinlto")) {
       parseClangOption(S, Arg->getSpelling());
Index: lld/trunk/ELF/InputFiles.h
===================================================================
--- lld/trunk/ELF/InputFiles.h
+++ lld/trunk/ELF/InputFiles.h
@@ -355,6 +355,20 @@
   return identify_magic(MB.getBuffer()) == llvm::file_magic::bitcode;
 }
 
+inline std::string updateSuffixInPath(llvm::StringRef Path) {
+  if (Path.endswith(Config->ThinLTOObjectSuffixReplace.first)) {
+    size_t pos = Path.rfind(Config->ThinLTOObjectSuffixReplace.first);
+    std::string SuffixedPath =
+        (Path.str().substr(0, pos) +
+         Config->ThinLTOObjectSuffixReplace.second.str());
+    return SuffixedPath;
+  } else {
+    error("cannot find suffix " +
+          Config->ThinLTOObjectSuffixReplace.first.str());
+    return "";
+  }
+}
+
 extern std::vector<BinaryFile *> BinaryFiles;
 extern std::vector<BitcodeFile *> BitcodeFiles;
 extern std::vector<LazyObjFile *> LazyObjFiles;
Index: lld/trunk/ELF/InputFiles.cpp
===================================================================
--- lld/trunk/ELF/InputFiles.cpp
+++ lld/trunk/ELF/InputFiles.cpp
@@ -1032,9 +1032,13 @@
   // this causes a collision which result in only one of the objects being
   // taken into consideration at LTO time (which very likely causes undefined
   // symbols later in the link stage).
+  std::string Path = MB.getBufferIdentifier().str();
+  if (Config->ThinLTOIndexOnly)
+    Path = updateSuffixInPath(MB.getBufferIdentifier());
+
   MemoryBufferRef MBRef(
       MB.getBuffer(),
-      Saver.save(ArchiveName + MB.getBufferIdentifier() +
+      Saver.save(ArchiveName + Path +
                  (ArchiveName.empty() ? "" : utostr(OffsetInArchive))));
   Obj = CHECK(lto::InputFile::create(MBRef), this);
 
Index: lld/trunk/ELF/LTO.cpp
===================================================================
--- lld/trunk/ELF/LTO.cpp
+++ lld/trunk/ELF/LTO.cpp
@@ -266,7 +266,8 @@
       if (F->AddedToLink || !isBitcode(F->MB))
         continue;
 
-      std::string Path = getThinLTOOutputFile(F->getName());
+      std::string Path = updateSuffixInPath(getThinLTOOutputFile(F->getName()));
+
       std::unique_ptr<raw_fd_ostream> OS = openFile(Path + ".thinlto.bc");
       if (!OS)
         continue;
Index: lld/trunk/test/ELF/lto/thinlto-object-suffix-replace.ll
===================================================================
--- lld/trunk/test/ELF/lto/thinlto-object-suffix-replace.ll
+++ lld/trunk/test/ELF/lto/thinlto-object-suffix-replace.ll
@@ -0,0 +1,51 @@
+; REQUIRES: x86
+
+; Test to make sure the thinlto-object-suffix-replace option is handled
+; correctly.
+
+; Generate bitcode file with summary, as well as a minimized bitcode without
+; the debug metadata for the thin link.
+; RUN: opt -thinlto-bc %s -thin-link-bitcode-file=%t1.thinlink.bc -o %t1.o
+
+; First perform the thin link on the normal bitcode file, and save the
+; resulting index.
+; RUN: ld.lld -m elf_x86_64 --plugin-opt=thinlto-index-only -shared %t1.o -o %t3
+; RUN: cp %t1.o.thinlto.bc %t1.o.thinlto.bc.orig
+
+; Next perform the thin link on the minimized bitcode file, and compare dump
+; of the resulting index to the above dump to ensure they are identical.
+; RUN: rm -f %t1.o.thinlto.bc
+; Make sure it isn't inadvertently using the regular bitcode file.
+; RUN: rm -f %t1.o
+; RUN: ld.lld -m elf_x86_64 --plugin-opt=thinlto-index-only \
+; RUN: --plugin-opt=thinlto-object-suffix-replace=".thinlink.bc;.o" \
+; RUN: -shared %t1.thinlink.bc -o %t3
+; RUN: diff %t1.o.thinlto.bc.orig %t1.o.thinlto.bc
+
+; Ensure lld generates error if object suffix replace option does not have 'old;new' format
+; RUN: rm -f %t1.o.thinlto.bc
+; RUN: not ld.lld -m elf_x86_64 --plugin-opt=thinlto-index-only \
+; RUN: --plugin-opt=thinlto-object-suffix-replace="abc:def" -shared %t1.thinlink.bc \
+; RUN: -o %t3 2>&1 | FileCheck %s --check-prefix=ERR1
+; ERR1: thinlto-object-suffix-replace expects 'old;new' format, but got abc:def
+
+; Ensure lld generates error if old suffix doesn't exist in file name
+; RUN: rm -f %t1.o
+; RUN: not ld.lld -m elf_x86_64 --plugin-opt=thinlto-index-only \
+; RUN: --plugin-opt=thinlto-object-suffix-replace=".abc;.o" -shared %t1.thinlink.bc \
+; RUN: -o %t3 2>&1 | FileCheck %s --check-prefix=ERR2
+; ERR2: cannot find suffix .abc
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @f() {
+entry:
+  ret void
+}
+
+!llvm.dbg.cu = !{}
+
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!llvm.module.flags = !{!1}