[Support] Fix `-ftime-trace-granularity` option

[anton-afanasyev]

Summary

Move -ftime-trace-granularity option to frontend options. Without patch
this option is showed up in the help for any tool that links libSupport.

[lebedev.ri]

clang/docs/ClangCommandLineReference.rst

1943–1947

While there add a description to -ftime-report and document how they are different?

clang/include/clang/Driver/Options.td

1759–1761

While there add description to ftime_report and document their difference?

llvm/lib/Support/TimeProfiler.cpp

27–30

Can TimeTraceGranularity perhaps be stored in TimeTraceProfilerInstance?

[sammccall]

clang/docs/ClangCommandLineReference.rst

1951

is there any possibility of wanting a granularity <1ms in the future? This sets up a backward-compatibility trap if so.

clang/lib/Frontend/CompilerInvocation.cpp

1772

You've got the default repeated here. Is it possible to set this conditionally here, or use the existing value as default like

Opts.TTG = getLastArgIntValue(Args, OPT_fttg_EQ, Opts.TTG, Diags)

llvm/lib/Support/TimeProfiler.cpp

28

why does this have a default value? It shouldn't be possible to use it without overwriting it, IIUC

28

static

[anton-afanasyev]

Update

[anton-afanasyev]

clang/docs/ClangCommandLineReference.rst

1951

Does it really make sense? One can use -ftime-trace-granularity=0, which can show all events.

llvm/lib/Support/TimeProfiler.cpp

27–30

Sure, thanks.

28

Moved to struct TimeProfiler member.

28

Hmm, ok, removing default value.

[lebedev.ri]

Looks ok

clang/docs/ClangCommandLineReference.rst

1943–1947

I mean, state that one is chrome json trace and another is console table output

[anton-afanasyev]

clang/docs/ClangCommandLineReference.rst

1943–1947

The difference is actually deeper at the moment. -ftime-report output is buggy, short and uninformative (as noted by @aras-p in his blog post http://aras-p.info/blog/2019/01/12/Investigating-compile-times-and-Clang-ftime-report/). I would like just to remove -ftime-report option as obsolete and unsupported.

[anton-afanasyev]

clang/lib/Frontend/CompilerInvocation.cpp

1772

Ok, done.

[anton-afanasyev]

Remove default repeat

[anton-afanasyev]

clang/docs/ClangCommandLineReference.rst

1951

To be more correct, this granularity value (-ftime-trace-granularity=0) will work after this old patch https://reviews.llvm.org/D63325 is commited.

clang/docs/ClangCommandLineReference.rst

 .. option:: -ftest-coverage
 
 .. option:: -fthinlto-index=<arg>
 
 Perform ThinLTO importing using provided function summary index
 
 .. option:: -fthreadsafe-statics, -fno-threadsafe-statics
 
 .. option:: -ftime-report
 
+.. option:: -ftime-trace
+
+Turn on time profiler
+
+.. option:: -ftime-trace-granularity=<arg>
+
+Minimum time granularity (in microseconds) traced by time profiler
+
 .. option:: -ftls-model=<arg>
 
 .. option:: -ftrap-function=<arg>
 
 Issue call to specified function rather than a trap instruction
 
 .. option:: -ftrapping-math, -fno-trapping-math
 

clang/include/clang/Basic/CodeGenOptions.def

 CODEGENOPT(SimplifyLibCalls  , 1, 1) ///< Set when -fbuiltin is enabled.
 CODEGENOPT(SoftFloat         , 1, 0) ///< -soft-float.
 CODEGENOPT(SpeculativeLoadHardening, 1, 0) ///< Enable speculative load hardening.
 CODEGENOPT(FineGrainedBitfieldAccesses, 1, 0) ///< Enable fine-grained bitfield accesses.
 CODEGENOPT(StrictEnums       , 1, 0) ///< Optimize based on strict enum definition.
 CODEGENOPT(StrictVTablePointers, 1, 0) ///< Optimize based on the strict vtable pointers
 CODEGENOPT(TimePasses        , 1, 0) ///< Set when -ftime-report is enabled.
 CODEGENOPT(TimeTrace         , 1, 0) ///< Set when -ftime-trace is enabled.
+VALUE_CODEGENOPT(TimeTraceGranularity, 32, 500) ///< Minimum time granularity (in microseconds),
+                                               ///< traced by time profiler
 CODEGENOPT(UnrollLoops       , 1, 0) ///< Control whether loops are unrolled.
 CODEGENOPT(RerollLoops       , 1, 0) ///< Control whether loops are rerolled.
 CODEGENOPT(NoUseJumpTables   , 1, 0) ///< Set when -fno-jump-tables is enabled.
 CODEGENOPT(UnsafeFPMath      , 1, 0) ///< Allow unsafe floating point optzns.
 CODEGENOPT(UnwindTables      , 1, 0) ///< Emit unwind tables.
 CODEGENOPT(VectorizeLoop     , 1, 0) ///< Run loop vectorizer.
 CODEGENOPT(VectorizeSLP      , 1, 0) ///< Run SLP vectorizer.
 CODEGENOPT(ProfileSampleAccurate, 1, 0) ///< Sample profile is accurate.

clang/include/clang/Driver/Options.td

 // These "special" warning flags are effectively processed as f_Group flags by the driver:
 // Just silence warnings about -Wlarger-than for now.
 def Wlarger_than_EQ : Joined<["-"], "Wlarger-than=">, Group<clang_ignored_f_Group>;
 def Wlarger_than_ : Joined<["-"], "Wlarger-than-">, Alias<Wlarger_than_EQ>;
 def Wframe_larger_than_EQ : Joined<["-"], "Wframe-larger-than=">, Group<f_Group>, Flags<[DriverOption]>;
 
 def : Flag<["-"], "fterminated-vtables">, Alias<fapple_kext>;
 def fthreadsafe_statics : Flag<["-"], "fthreadsafe-statics">, Group<f_Group>;
 def ftime_report : Flag<["-"], "ftime-report">, Group<f_Group>, Flags<[CC1Option]>;
-def ftime_trace : Flag<["-"], "ftime-trace">, Group<f_Group>, Flags<[CC1Option, CoreOption]>;
+def ftime_trace : Flag<["-"], "ftime-trace">, Group<f_Group>,
+  HelpText<"Turn on time profiler">, Flags<[CC1Option, CoreOption]>;
+def ftime_trace_granularity_EQ : Joined<["-"], "ftime-trace-granularity=">, Group<f_Group>,
+  HelpText<"Minimum time granularity (in microseconds) traced by time profiler">,
+  Flags<[CC1Option, CoreOption]>;
 def ftlsmodel_EQ : Joined<["-"], "ftls-model=">, Group<f_Group>, Flags<[CC1Option]>;
 def ftrapv : Flag<["-"], "ftrapv">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Trap on integer overflow">;
 def ftrapv_handler_EQ : Joined<["-"], "ftrapv-handler=">, Group<f_Group>,
   MetaVarName<"<function name>">,
   HelpText<"Specify the function to be called on overflow">;
 def ftrapv_handler : Separate<["-"], "ftrapv-handler">, Group<f_Group>, Flags<[CC1Option]>;
 def ftrap_function_EQ : Joined<["-"], "ftrap-function=">, Group<f_Group>, Flags<[CC1Option]>,

clang/include/clang/Frontend/FrontendOptions.h

public:
   std::string OverrideRecordLayoutsFile;
 
   /// Auxiliary triple for CUDA compilation.
   std::string AuxTriple;
 
   /// Filename to write statistics to.
   std::string StatsFile;
 
+  /// Minimum time granularity (in microseconds) traced by time profiler.
+  unsigned TimeTraceGranularity;
+
 public:
   FrontendOptions()
       : DisableFree(false), RelocatablePCH(false), ShowHelp(false),
         ShowStats(false), ShowTimers(false), TimeTrace(false),
         ShowVersion(false), FixWhatYouCan(false), FixOnlyWarnings(false),
         FixAndRecompile(false), FixToTemporaries(false),
         ARCMTMigrateEmitARCErrors(false), SkipFunctionBodies(false),
         UseGlobalModuleIndex(true), GenerateGlobalModuleIndex(true),
         ASTDumpDecls(false), ASTDumpLookups(false),
         BuildingImplicitModule(false), ModulesEmbedAllFiles(false),
-        IncludeTimestamps(true) {}
+        IncludeTimestamps(true), TimeTraceGranularity(500) {}
 
   /// getInputKindForExtension - Return the appropriate input kind for a file
   /// extension. For example, "c" would return InputKind::C.
   ///
   /// \return The input kind for the extension, or InputKind::Unknown if the
   /// extension is not recognized.
   static InputKind getInputKindForExtension(StringRef Extension);
 };
 
 } // namespace clang
 
 #endif // LLVM_CLANG_FRONTEND_FRONTENDOPTIONS_H

clang/lib/Driver/ToolChains/Clang.cpp

if (Args.getLastArg(options::OPT_fapple_kext) ||
       (Args.hasArg(options::OPT_mkernel) && types::isCXX(InputType)))
     CmdArgs.push_back("-fapple-kext");
 
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_sender_dependent_dispatch);
   Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_print_source_range_info);
   Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_parseable_fixits);
   Args.AddLastArg(CmdArgs, options::OPT_ftime_report);
   Args.AddLastArg(CmdArgs, options::OPT_ftime_trace);
+  Args.AddLastArg(CmdArgs, options::OPT_ftime_trace_granularity_EQ);
   Args.AddLastArg(CmdArgs, options::OPT_ftrapv);
   Args.AddLastArg(CmdArgs, options::OPT_malign_double);
 
   if (Arg *A = Args.getLastArg(options::OPT_ftrapv_handler_EQ)) {
     CmdArgs.push_back("-ftrapv-handler");
     CmdArgs.push_back(A->getValue());
   }
 

clang/lib/Frontend/CompilerInvocation.cpp

static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
   Opts.OutputFile = Args.getLastArgValue(OPT_o);
   Opts.Plugins = Args.getAllArgValues(OPT_load);
   Opts.RelocatablePCH = Args.hasArg(OPT_relocatable_pch);
   Opts.ShowHelp = Args.hasArg(OPT_help);
   Opts.ShowStats = Args.hasArg(OPT_print_stats);
   Opts.ShowTimers = Args.hasArg(OPT_ftime_report);
   Opts.PrintSupportedCPUs = Args.hasArg(OPT_print_supported_cpus);
   Opts.TimeTrace = Args.hasArg(OPT_ftime_trace);
+  Opts.TimeTraceGranularity =
+      getLastArgIntValue(Args, OPT_ftime_trace_granularity_EQ, 500, Diags);
   Opts.ShowVersion = Args.hasArg(OPT_version);
   Opts.ASTMergeFiles = Args.getAllArgValues(OPT_ast_merge);
   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
   Opts.FixWhatYouCan = Args.hasArg(OPT_fix_what_you_can);
   Opts.FixOnlyWarnings = Args.hasArg(OPT_fix_only_warnings);
   Opts.FixAndRecompile = Args.hasArg(OPT_fixit_recompile);
   Opts.FixToTemporaries = Args.hasArg(OPT_fixit_to_temp);
   Opts.ASTDumpDecls = Args.hasArg(OPT_ast_dump, OPT_ast_dump_EQ);

clang/test/Driver/check-time-trace.cpp

 // REQUIRES: shell
-// RUN: %clangxx -S -ftime-trace -mllvm --time-trace-granularity=0 -o %T/check-time-trace %s
+// RUN: %clangxx -S -ftime-trace -ftime-trace-granularity=0 -o %T/check-time-trace %s
 // RUN: cat %T/check-time-trace.json \
 // RUN:   | %python -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' \
 // RUN:   | FileCheck %s
 
 // CHECK: "traceEvents": [
 // CHECK: "args":
 // CHECK: "detail":
 // CHECK: "dur":

clang/tools/driver/cc1_main.cpp

#endif
   // Buffer diagnostics from argument parsing so that we can output them using a
   // well formed diagnostic object.
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
   TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer);
   bool Success = CompilerInvocation::CreateFromArgs(
       Clang->getInvocation(), Argv.begin(), Argv.end(), Diags);
 
-  if (Clang->getFrontendOpts().TimeTrace)
-    llvm::timeTraceProfilerInitialize();
-
+  if (Clang->getFrontendOpts().TimeTrace) {
+    llvm::timeTraceProfilerInitialize(
+        Clang->getFrontendOpts().TimeTraceGranularity);
+  }
   // --print-supported-cpus takes priority over the actual compilation.
   if (Clang->getFrontendOpts().PrintSupportedCPUs)
     return PrintSupportedCPUs(Clang->getTargetOpts().Triple);
 
   // Infer the builtin include path if unspecified.
   if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&
       Clang->getHeaderSearchOpts().ResourceDir.empty())
     Clang->getHeaderSearchOpts().ResourceDir =

llvm/include/llvm/Support/TimeProfiler.h

 namespace llvm {
 
 struct TimeTraceProfiler;
 extern TimeTraceProfiler *TimeTraceProfilerInstance;
 
 /// Initialize the time trace profiler.
 /// This sets up the global \p TimeTraceProfilerInstance
 /// variable to be the profiler instance.
-void timeTraceProfilerInitialize();
+void timeTraceProfilerInitialize(unsigned TimeTraceGranularity);
 
 /// Cleanup the time trace profiler, if it was initialized.
 void timeTraceProfilerCleanup();
 
 /// Is the time trace profiler enabled, i.e. initialized?
 inline bool timeTraceProfilerEnabled() {
   return TimeTraceProfilerInstance != nullptr;
 }

llvm/lib/Support/TimeProfiler.cpp

 #include <chrono>
 #include <string>
 #include <vector>
 
 using namespace std::chrono;
 
 namespace llvm {
 
-static cl::opt<unsigned> TimeTraceGranularity(
-    "time-trace-granularity",
-    cl::desc(
-        "Minimum time granularity (in microseconds) traced by time profiler"),
-    cl::init(500));
+// Minimum time granularity (in microseconds) traced by time profiler
+unsigned TimeTraceGranularity = 500;
 
 TimeTraceProfiler *TimeTraceProfilerInstance = nullptr;
 
 typedef duration<steady_clock::rep, steady_clock::period> DurationType;
 typedef std::pair<size_t, DurationType> CountAndDurationType;
 typedef std::pair<std::string, CountAndDurationType>
     NameAndCountAndDurationType;
 
 struct Entry {
   time_point<steady_clock> Start;
struct TimeTraceProfiler {
   }
 
   SmallVector<Entry, 16> Stack;
   SmallVector<Entry, 128> Entries;
   StringMap<CountAndDurationType> CountAndTotalPerName;
   time_point<steady_clock> StartTime;
 };
 
-void timeTraceProfilerInitialize() {
+void timeTraceProfilerInitialize(unsigned TimeTraceGranularity_) {
   assert(TimeTraceProfilerInstance == nullptr &&
          "Profiler should not be initialized");
   TimeTraceProfilerInstance = new TimeTraceProfiler();
+  TimeTraceGranularity = TimeTraceGranularity_;
 }
 
 void timeTraceProfilerCleanup() {
   delete TimeTraceProfilerInstance;
   TimeTraceProfilerInstance = nullptr;
 }
 
 void timeTraceProfilerWrite(raw_pwrite_stream &OS) {