[ThinLTO] Always create linked objects file for --thinlto-index-only=

Summary:
ThinLTO indexing may decide to skip all objects. If we don't write something to
the list build system may consider this as failure or linker can reuse a file
from the previews build.

Reviewers: pcc, tejohnson

Subscribers: mehdi_amini, inglorion, eraman, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D43415

llvm-svn: 325819

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/tools/llvm-lto2/llvm-lto2.cpp b/llvm/tools/llvm-lto2/llvm-lto2.cpp
index 2ba7bd55747..0baa34eb513 100644
--- a/llvm/tools/llvm-lto2/llvm-lto2.cpp
+++ b/llvm/tools/llvm-lto2/llvm-lto2.cpp
@@ -243,7 +243,11 @@ static int run(int argc, char **argv) {
 
   ThinBackend Backend;
   if (ThinLTODistributedIndexes)
-    Backend = createWriteIndexesThinBackend("", "", true, "", {});
+    Backend = createWriteIndexesThinBackend(/* OldPrefix */ "",
+                                            /* NewPrefix */ "",
+                                            /* ShouldEmitImportsFiles */ true,
+                                            /* LinkedObjectsFile */ nullptr,
+                                            /* OnWrite */ {});
   else
     Backend = createInProcessThinBackend(Threads);
   LTO Lto(std::move(Conf), std::move(Backend));