Index: test/ThinLTO/X86/funcimport.ll
===================================================================
--- test/ThinLTO/X86/funcimport.ll
+++ test/ThinLTO/X86/funcimport.ll
@@ -3,6 +3,9 @@
 ; RUN: opt -module-summary %p/Inputs/funcimport.ll -o %t2.bc
 ; RUN: llvm-lto -thinlto-action=thinlink -o %t3.bc %t.bc %t2.bc
 
+; RUN: llvm-lto -thinlto-index-stats %t3.bc | FileCheck %s -check-prefix=STATS
+; STATS: Index {{.*}} contains 24 nodes (13 functions, 3 alias, 8 globals) and 19 edges (8 refs and 11 calls)
+
 ; Ensure statics are promoted/renamed correctly from this file (all but
 ; constant variable need promotion).
 ; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=EXPORTSTATIC
Index: tools/llvm-lto/llvm-lto.cpp
===================================================================
--- tools/llvm-lto/llvm-lto.cpp
+++ tools/llvm-lto/llvm-lto.cpp
@@ -42,6 +42,11 @@
                            "(default = '-O2')"),
              cl::Prefix, cl::ZeroOrMore, cl::init('2'));
 
+static cl::opt<bool>
+    IndexStats("thinlto-index-stats",
+               cl::desc("Print statistic for the index in every input files"),
+               cl::init(false));
+
 static cl::opt<bool> DisableVerify(
     "disable-verify", cl::init(false),
     cl::desc("Do not run the verifier during the optimization pipeline"));
@@ -725,6 +730,38 @@
     return 0;
   }
 
+  if (IndexStats) {
+    for (auto &Filename : InputFilenames) {
+      CurrentActivity = "loading file '" + Filename + "'";
+      ErrorOr<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
+          llvm::getModuleSummaryIndexForFile(Filename, diagnosticHandler);
+      error(IndexOrErr, "error " + CurrentActivity);
+      std::unique_ptr<ModuleSummaryIndex> Index = std::move(IndexOrErr.get());
+      CurrentActivity = "";
+      // Skip files without a module summary.
+      if (!Index)
+        report_fatal_error(Filename + " does not contain an index");
+
+      unsigned Calls = 0, Refs = 0, Functions = 0, Alias = 0, Globals = 0;
+      for (auto &Summaries : *Index) {
+        for (auto &Summary : Summaries.second) {
+          Refs += Summary->refs().size();
+          if (auto *FuncSummary = dyn_cast<FunctionSummary>(Summary.get())) {
+            Functions++;
+            Calls += FuncSummary->calls().size();
+          } else if (isa<AliasSummary>(Summary.get()))
+            Alias++;
+          else
+            Globals++;
+        }
+      }
+      outs() << "Index " << Filename << " contains "
+      << (Alias + Globals + Functions) << " nodes (" << Functions << " functions, " << Alias << " alias, " << Globals << " globals) and "  << (Calls + Refs)
+      << " edges (" << Refs << " refs and " << Calls << " calls)\n";
+    }
+    return 0;
+  }
+
   if (CheckHasObjC) {
     for (auto &Filename : InputFilenames) {
       ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =