[PATCH] D45531: [GoldPlugin] Add support for -save-stats=obj.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: MatzeB, tejohnson, espindola.
Herald added a subscriber: mehdi_amini.

This patch adds a -save-stats=obj plugin option, that writes
the collected stats to a output_name.stats file. The corresponding
Clang option is implemented in Clang's driver, so there is nothing we
can re-use unfortunately.

I am not sure what the best option is here. I basically want to get an
option to dump the stats collected during LTO to a file, so they are
included when collecting stats from the test-suite compiled with LTO.
This will also require a change to the test-suite to add this option to
the LDFLAGS.

This is a very naive approach, please let me know if you think there is
a better way to collect the stats for LTO.


https://reviews.llvm.org/D45531

Files:
  tools/gold/gold-plugin.cpp


Index: tools/gold/gold-plugin.cpp
===================================================================
--- tools/gold/gold-plugin.cpp
+++ tools/gold/gold-plugin.cpp
@@ -199,6 +199,7 @@
   static bool new_pass_manager = false;
   // Debug new pass manager
   static bool debug_pass_manager = false;
+  static bool save_stats_obj = false;
 
   static void process_plugin_option(const char *opt_)
   {
@@ -262,6 +263,8 @@
       new_pass_manager = true;
     } else if (opt == "debug-pass-manager") {
       debug_pass_manager = true;
+    } else if (opt == "-save-stats=obj") {
+      save_stats_obj = true;
     } else {
       // Save this option to pass to the code generator.
       // ParseCommandLineOptions() expects argv[0] to be program name. Lazily
@@ -1030,6 +1033,9 @@
   if (unsigned NumOpts = options::extra.size())
     cl::ParseCommandLineOptions(NumOpts, &options::extra[0]);
 
+  if (options::save_stats_obj)
+    llvm::EnableStatistics(false);
+
   std::vector<std::pair<SmallString<128>, bool>> Files = runLTO();
 
   if (options::TheOutputType == options::OT_DISABLE ||
@@ -1051,6 +1057,14 @@
       set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK)
     message(LDPL_FATAL, "Unable to set the extra library path.");
 
+  if (options::save_stats_obj) {
+    std::error_code EC;
+    raw_fd_ostream OS(output_name+".stats", EC, sys::fs::OpenFlags::F_None);
+    if (EC)
+      message(LDPL_FATAL, "Failed to write the stats file.");
+    else
+      llvm::PrintStatisticsJSON(OS);
+  }
   return LDPS_OK;
 }
 


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