[LTO] Add stats-file option to LTO/Config.h.

This patch adds a StatsFile option to LTO/Config.h and updates both
LLVMGold and llvm-lto2 to set it.

Reviewers: MatzeB, tejohnson, espindola

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D45531

llvm-svn: 330411

1 files changed, 21 insertions, 3 deletions

diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index e4dffbf..186e3d2 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/LTO/LTO.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Bitcode/BitcodeReader.h"
@@ -791,9 +792,26 @@ Error LTO::run(AddStreamFn AddStream, NativeObjectCache Cache) {
   };
   computeDeadSymbols(ThinLTO.CombinedIndex, GUIDPreservedSymbols, isPrevailing);
 
-  if (auto E = runRegularLTO(AddStream))
-    return E;
-  return runThinLTO(AddStream, Cache);
+  // 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();
+  }
+
+  Error Result = runRegularLTO(AddStream);
+  if (!Result)
+    Result = runThinLTO(AddStream, Cache);
+
+  if (StatsFile)
+    PrintStatisticsJSON(StatsFile->os());
+
+  return Result;
 }
 
 Error LTO::runRegularLTO(AddStreamFn AddStream) {