2 files changed, 41 insertions, 13 deletions

diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 1accbf40b96..ab5b78071c6 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -885,16 +885,10 @@ Error LTO::run(AddStreamFn AddStream, NativeObjectCache Cache) {
                                   isPrevailing, Conf.OptLevel > 0);
 
   // Setup output file to emit statistics.
-  std::unique_ptr<ToolOutputFile> StatsFile = nullptr;
-  if (!Conf.StatsFile.empty()) {
-    EnableStatistics(false);
-    std::error_code EC;
-    StatsFile =
-        llvm::make_unique<ToolOutputFile>(Conf.StatsFile, EC, sys::fs::F_None);
-    if (EC)
-      return errorCodeToError(EC);
-    StatsFile->keep();
-  }
+  auto StatsFileOrErr = setupStatsFile(Conf.StatsFile);
+  if (!StatsFileOrErr)
+    return StatsFileOrErr.takeError();
+  std::unique_ptr<ToolOutputFile> StatsFile = std::move(StatsFileOrErr.get());
 
   // Finalize linking of regular LTO modules containing summaries now that
   // we have computed liveness information.
@@ -1343,3 +1337,20 @@ lto::setupOptimizationRemarks(LLVMContext &Context,
   DiagnosticFile->keep();
   return std::move(DiagnosticFile);
 }
+
+Expected<std::unique_ptr<ToolOutputFile>>
+lto::setupStatsFile(StringRef StatsFilename) {
+  // Setup output file to emit statistics.
+  if (StatsFilename.empty())
+    return nullptr;
+
+  llvm::EnableStatistics(false);
+  std::error_code EC;
+  auto StatsFile =
+      llvm::make_unique<ToolOutputFile>(StatsFilename, EC, sys::fs::F_None);
+  if (EC)
+    return errorCodeToError(EC);
+
+  StatsFile->keep();
+  return std::move(StatsFile);
+}
diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp
index f02907f7a86..79d41ee8966 100644
--- a/llvm/lib/LTO/LTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -95,6 +95,11 @@ cl::opt<bool> LTOPassRemarksWithHotness(
     "lto-pass-remarks-with-hotness",
     cl::desc("With PGO, include profile count in optimization remarks"),
     cl::Hidden);
+
+cl::opt<std::string> LTOStatsFile(
+    "lto-stats-file",
+    cl::desc("Save statistics to the specified file"),
+    cl::Hidden);
 }
 
 LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
@@ -518,6 +523,14 @@ bool LTOCodeGenerator::optimize(bool DisableVerify, bool DisableInline,
   }
   DiagnosticOutputFile = std::move(*DiagFileOrErr);
 
+  // Setup output file to emit statistics.
+  auto StatsFileOrErr = lto::setupStatsFile(LTOStatsFile);
+  if (!StatsFileOrErr) {
+    errs() << "Error: " << toString(StatsFileOrErr.takeError()) << "\n";
+    report_fatal_error("Can't get an output file for the statistics");
+  }
+  StatsFile = std::move(StatsFileOrErr.get());
+
   // We always run the verifier once on the merged module, the `DisableVerify`
   // parameter only applies to subsequent verify.
   verifyMergedModuleOnce();
@@ -584,9 +597,13 @@ bool LTOCodeGenerator::compileOptimized(ArrayRef<raw_pwrite_stream *> Out) {
                               [&]() { return createTargetMachine(); }, FileType,
                               ShouldRestoreGlobalsLinkage);
 
-  // If statistics were requested, print them out after codegen.
-  if (llvm::AreStatisticsEnabled())
-    llvm::PrintStatistics();
+  // If statistics were requested, save them to the specified file or
+  // print them out after codegen.
+  if (StatsFile)
+    PrintStatisticsJSON(StatsFile->os());
+  else if (AreStatisticsEnabled())
+    PrintStatistics();
+
   reportAndResetTimings();
 
   finishOptimizationRemarks();