Basic: Add -fine-grained-timers flag

By default, -stats-output-dir does not collect per-request timers and
counters, because of overhead.

Author: slavapestov

include/swift/Basic/Statistic.h

@@ -167,6 +167,10 @@ class UnifiedStatsReporter {
   std::unique_ptr<StatsProfilers> EventProfilers;
   std::unique_ptr<StatsProfilers> EntityProfilers;
 
+  /// Whether fine-grained timers are enabled. In practice, this means request
+  /// evaluator requests. This will have a runtime performance impact.
+  bool FineGrainedTimers;
+
   /// Whether we are currently flushing statistics and should not therefore
   /// record any additional stats until we've finished.
   bool IsFlushingTracesAndProfiles;
@@ -179,6 +183,7 @@ class UnifiedStatsReporter {
                        StringRef Directory,
                        SourceManager *SM,
                        clang::SourceManager *CSM,
+                       bool FineGrainedTimers,
                        bool TraceEvents,
                        bool ProfileEvents,
                        bool ProfileEntities);
@@ -190,13 +195,16 @@ class UnifiedStatsReporter {
                        StringRef OutputType,
                        StringRef OptType,
                        StringRef Directory,
-                       SourceManager *SM=nullptr,
-                       clang::SourceManager *CSM=nullptr,
-                       bool TraceEvents=false,
-                       bool ProfileEvents=false,
-                       bool ProfileEntities=false);
+                       SourceManager *SM,
+                       clang::SourceManager *CSM,
+                       bool FineGrainedTimers,
+                       bool TraceEvents,
+                       bool ProfileEvents,
+                       bool ProfileEntities);
   ~UnifiedStatsReporter();
 
+  bool fineGrainedTimers() const { return FineGrainedTimers; }
+
   AlwaysOnDriverCounters &getDriverCounters();
   AlwaysOnFrontendCounters &getFrontendCounters();
   void flushTracesAndProfiles();

include/swift/Frontend/FrontendOptions.h

@@ -228,6 +228,10 @@ class FrontendOptions {
   /// The path to which we should output statistics files.
   std::string StatsOutputDir;
 
+  /// Whether to enable timers tracking individual requests. This adds some
+  /// runtime overhead.
+  bool FineGrainedTimers = false;
+
   /// Trace changes to stats to files in StatsOutputDir.
   bool TraceStats = false;
 

include/swift/Option/Options.td

@@ -361,6 +361,9 @@ def driver_time_compilation : Flag<["-"], "driver-time-compilation">,
 def stats_output_dir: Separate<["-"], "stats-output-dir">,
   Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
   HelpText<"Directory to write unified compilation-statistics files to">;
+def fine_grained_timers: Flag<["-"], "fine-grained-timers">,
+  Flags<[FrontendOption, HelpHidden]>,
+  HelpText<"Enable per-request timers">;
 def trace_stats_events: Flag<["-"], "trace-stats-events">,
   Flags<[FrontendOption, HelpHidden]>,
   HelpText<"Trace changes to stats in -stats-output-dir">;

lib/AST/ASTContext.cpp

@@ -928,12 +928,16 @@ swift::detail::ImportPathBuilder_getIdentifierImpl(ASTContext &ctx,
 
 /// Set a new stats reporter.
 void ASTContext::setStatsReporter(UnifiedStatsReporter *stats) {
-  if (stats) {
-    stats->getFrontendCounters().NumASTBytesAllocated =
-        getAllocator().getBytesAllocated();
-  }
-  evaluator.setStatsReporter(stats);
+  if (!stats)
+    return;
+
   Stats = stats;
+
+  stats->getFrontendCounters().NumASTBytesAllocated =
+      getAllocator().getBytesAllocated();
+
+  if (stats->fineGrainedTimers())
+    evaluator.setStatsReporter(stats);
 }
 
 /// getIdentifier - Return the uniqued and AST-Context-owned version of the

lib/Basic/Statistic.cpp

@@ -319,6 +319,7 @@ UnifiedStatsReporter::UnifiedStatsReporter(StringRef ProgramName,
                                            StringRef Directory,
                                            SourceManager *SM,
                                            clang::SourceManager *CSM,
+                                           bool FineGrainedTimers,
                                            bool TraceEvents,
                                            bool ProfileEvents,
                                            bool ProfileEntities)
@@ -329,7 +330,7 @@ UnifiedStatsReporter::UnifiedStatsReporter(StringRef ProgramName,
                                  OutputType,
                                  OptType),
                          Directory,
-                         SM, CSM,
+                         SM, CSM, FineGrainedTimers,
                          TraceEvents, ProfileEvents, ProfileEntities)
 {
 }
@@ -339,6 +340,7 @@ UnifiedStatsReporter::UnifiedStatsReporter(StringRef ProgramName,
                                            StringRef Directory,
                                            SourceManager *SM,
                                            clang::SourceManager *CSM,
+                                           bool FineGrainedTimers,
                                            bool TraceEvents,
                                            bool ProfileEvents,
                                            bool ProfileEntities)
@@ -355,7 +357,8 @@ UnifiedStatsReporter::UnifiedStatsReporter(StringRef ProgramName,
     SourceMgr(SM),
     ClangSourceMgr(CSM),
     RecursiveTimers(std::make_unique<RecursionSafeTimers>()),
-    IsFlushingTracesAndProfiles(false)
+    IsFlushingTracesAndProfiles(false),
+    FineGrainedTimers(FineGrainedTimers)
 {
   path::append(StatsFilename, makeStatsFileName(ProgramName, AuxName));
   path::append(TraceFilename, makeTraceFileName(ProgramName, AuxName));

lib/Driver/Driver.cpp

@@ -516,7 +516,13 @@ createStatsReporter(const llvm::opt::InputArgList *ArgList,
                                                  DefaultTargetTriple,
                                                  OutputType,
                                                  OptType,
-                                                 A->getValue());
+                                                 A->getValue(),
+                                                 nullptr,
+                                                 nullptr,
+                                                 false,
+                                                 false,
+                                                 false,
+                                                 false);
 }
 
 static bool

lib/Frontend/ArgsToFrontendOptionsConverter.cpp

@@ -416,6 +416,9 @@ void ArgsToFrontendOptionsConverter::computeDebugTimeOptions() {
   using namespace options;
   if (const Arg *A = Args.getLastArg(OPT_stats_output_dir)) {
     Opts.StatsOutputDir = A->getValue();
+    if (Args.getLastArg(OPT_fine_grained_timers)) {
+      Opts.FineGrainedTimers = true;
+    }
     if (Args.getLastArg(OPT_trace_stats_events)) {
       Opts.TraceStats = true;
     }

lib/Frontend/Frontend.cpp

@@ -381,6 +381,7 @@ void CompilerInstance::setupStatsReporter() {
       StatsOutputDir,
       &getSourceMgr(),
       getClangSourceManager(getASTContext()),
+      Invoke.getFrontendOptions().FineGrainedTimers,
       Invoke.getFrontendOptions().TraceStats,
       Invoke.getFrontendOptions().ProfileEvents,
       Invoke.getFrontendOptions().ProfileEntities);