[clang][LTO] Pass-through remarks options and set auto hotness threshold

[weiwang]

Summary

Expand remarks hotness threshold option -fdiagnostics-hotness-threshold in clang
driver command-line to both filtering remarks by hotness threshold from profile
summary and automatic remarks options pass-through to linker.

Remarks hotness filtering relies on several driver options. Table below lists
how different options are correlated and affect final remarks outputs:

profile	hotness	threshold	remarks printed
No	No	No	All
No	No	Yes	None
No	Yes	No	All
No	Yes	Yes	None
Yes	No	No	All
Yes	No	Yes	None
Yes	Yes	No	All
Yes	Yes	Yes	>=threshold

The new argument value -fdiagnostics-hotness-threshold=auto indicates threshold
will be synced with hotness threshold from profile summary during compilation.
In addition, when the following conditions are met, remarks related options are
passed into linker as well:

1. LTO is enabled;
2. Single arch target is specified;
3. The linker is lld;

The "auto" threshold relies on the availability of profile summary. In case of
missing such information, no remarks will be generated.

This gives novice user a convenient way to collect and filter remarks throughout
a typical toolchain invocation with sample profile and LTO using single switch
from the clang driver.

A typical use of this option from clang command-line:

• Using -Rpass* options to print remarks to screen:

clang -fuse-ld=lld -flto=thin

-fprofile-sample-use=foo_sample.txt
-Rpass=inline
-Rpass-missed=inline -Rpass-analysis=inline
-fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=auto
-o foo foo.cpp

Remarks will be dumped to screen from both pre-lto and lto compilation.

• Using serialized remarks options:

clang -fuse-ld=lld -flto=thin

-fprofile-sample-use=foo_sample.txt -fsave-optimization-record
-fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=auto
-o foo foo.cpp

This will produce multiple yaml files containing optimization remarks:

• foo.opt.yaml : remarks from pre-lto
• foo.opt.ld.yaml.thin.1.yaml: remark during lto

Both types of options can be used together.

Given its restricted use cases, this shouldn't be viewed as a complete
replacement of current remarks option handling for the linker.

In order to make the option consistent across various tools, the support for the
new 'auto' argument is also available in the following tools:

• lld: -opt-remarks-with-hotness=auto
• llvm-lto: -lto-pass-remarks-hotness-threshold=auto
• opt/llc: --pass-remarks-hotness-threshold=auto

[weiwang]

I put everything together in a single diff so that it is easier to get the whole idea. The change itself is too big to go in as a single diff, and I'd like to get inputs on how to split it.

[weiwang]

Fix msvc build failure

[weiwang]

still waiting for inputs. Thanks.

[weiwang]

Diff has been split into 3 smaller ones:

1. [lld] Enable remarks hotness filtering in lld: https://reviews.llvm.org/D85809
2. [clang] Pass-through remarks options to lld: https://reviews.llvm.org/D85810
3. [remarks] Optimization remarks hotness filtering from profile summary: https://reviews.llvm.org/D85808

clang/include/clang/Basic/CodeGenOptions.h

public:
   /// coverage pass should actually not be instrumented.
   std::vector<std::string> SanitizeCoverageBlocklistFiles;
 
   /// Executable and command-line used to create a given CompilerInvocation.
   /// Most of the time this will be the full -cc1 command.
   const char *Argv0 = nullptr;
   ArrayRef<const char *> CommandLineArgs;
 
+  /// The minimum hotness value a diagnostic needs in order to be included in
+  /// optimization diagnostics.
+  ///
+  /// The threshold is an Optional value, which maps to one of the 3 states:
+  /// 1. 0            => threshold disabled. All emarks will be printed.
+  /// 2. positive int => manual threshold by user. Remarks with hotness exceed
+  ///                    threshold will be printed.
+  /// 3. None         => 'auto' threshold by user. The actual value is not
+  ///                    available at command line, but will be synced with
+  ///                    hotness threhold from profile summary during
+  ///                    compilation.
+  ///
+  /// If threshold option is not specified, it is disabled by default.
+  Optional<uint64_t> DiagnosticsHotnessThreshold = 0;
+
 public:
   // Define accessors/mutators for code generation options of enumeration type.
 #define CODEGENOPT(Name, Bits, Default)
 #define ENUM_CODEGENOPT(Name, Type, Bits, Default) \
   Type get##Name() const { return static_cast<Type>(Name); } \
   void set##Name(Type Value) { Name = static_cast<unsigned>(Value); }
 #include "clang/Basic/CodeGenOptions.def"
 

clang/include/clang/Basic/CodeGenOptions.def

 
 /// Number of path components to strip when emitting checks. (0 == full
 /// filename)
 VALUE_CODEGENOPT(EmitCheckPathComponentsToStrip, 32, 0)
 
 /// Whether to report the hotness of the code region for optimization remarks.
 CODEGENOPT(DiagnosticsWithHotness, 1, 0)
 
-/// The minimum hotness value a diagnostic needs in order to be included in
-/// optimization diagnostics.
-VALUE_CODEGENOPT(DiagnosticsHotnessThreshold, 32, 0)
-
 /// Whether copy relocations support is available when building as PIE.
 CODEGENOPT(PIECopyRelocations, 1, 0)
 
 /// Whether we should use the undefined behaviour optimization for control flow
 /// paths that reach the end of a function without executing a required return.
 CODEGENOPT(StrictReturn, 1, 1)
 
 /// Whether emit extra debug info for sample pgo profile collection.

clang/include/clang/Basic/DiagnosticDriverKinds.td

 def err_drv_unable_to_remove_file : Error<
   "unable to remove file: %0">;
 def err_drv_unable_to_set_working_directory : Error <
   "unable to set working directory: %0">;
 def err_drv_command_failure : Error<
   "unable to execute command: %0">;
 def err_drv_invalid_darwin_version : Error<
   "invalid Darwin version number: %0">;
+def err_drv_invalid_diagnotics_hotness_threshold : Error<
+  "invalid argument in '%0', only integer or 'auto' is supported">;
 def err_drv_missing_argument : Error<
   "argument to '%0' is missing (expected %1 value%s1)">;
 def err_drv_invalid_Xarch_argument_with_args : Error<
   "invalid Xarch argument: '%0', options requiring arguments are unsupported">;
 def err_drv_invalid_Xarch_argument_isdriver : Error<
   "invalid Xarch argument: '%0', cannot change driver behavior inside Xarch argument">;
 def err_drv_Xopenmp_target_missing_triple : Error<
   "cannot deduce implicit triple value for -Xopenmp-target, specify triple using -Xopenmp-target=<triple>">;

clang/include/clang/Driver/Driver.h

 
 /// \return True if the last defined optimization level is -Ofast.
 /// And False otherwise.
 bool isOptimizationLevelFast(const llvm::opt::ArgList &Args);
 
 /// \return True if the argument combination will end up generating remarks.
 bool willEmitRemarks(const llvm::opt::ArgList &Args);
 
+/// \return True if the argument combination will end up outputing remarks
+/// onto screen.
+/// This checks for clang specific R-value ('-Rpass-*') group.
+bool hasRpassOptions(const llvm::opt::ArgList &Args);
+
 } // end namespace driver
 } // end namespace clang
 
 #endif

clang/include/clang/Driver/Options.td

 def fdiagnostics_parseable_fixits : Flag<["-"], "fdiagnostics-parseable-fixits">, Group<f_clang_Group>,
     Flags<[CoreOption, CC1Option]>, HelpText<"Print fix-its in machine parseable form">;
 def fdiagnostics_print_source_range_info : Flag<["-"], "fdiagnostics-print-source-range-info">,
     Group<f_clang_Group>,  Flags<[CC1Option]>,
     HelpText<"Print source range spans in numeric form">;
 def fdiagnostics_show_hotness : Flag<["-"], "fdiagnostics-show-hotness">, Group<f_Group>,
     Flags<[CC1Option]>, HelpText<"Enable profile hotness information in diagnostic line">;
 def fdiagnostics_hotness_threshold_EQ : Joined<["-"], "fdiagnostics-hotness-threshold=">,
-    Group<f_Group>, Flags<[CC1Option]>, MetaVarName<"<number>">,
-    HelpText<"Prevent optimization remarks from being output if they do not have at least this profile count">;
+    Group<f_Group>, Flags<[CC1Option]>, MetaVarName<"<value>">,
+    HelpText<"Prevent optimization remarks from being output if they do not have at least this profile count. "
+    "Use 'auto' to apply the threshold from profile summary">;
 def fdiagnostics_show_option : Flag<["-"], "fdiagnostics-show-option">, Group<f_Group>,
     HelpText<"Print option name with mappable diagnostics">;
 def fdiagnostics_show_note_include_stack : Flag<["-"], "fdiagnostics-show-note-include-stack">,
     Group<f_Group>, Flags<[CC1Option]>, HelpText<"Display include stacks for diagnostic notes">;
 def fdiagnostics_format_EQ : Joined<["-"], "fdiagnostics-format=">, Group<f_clang_Group>;
 def fdiagnostics_show_category_EQ : Joined<["-"], "fdiagnostics-show-category=">, Group<f_clang_Group>;
 def fdiagnostics_show_template_tree : Flag<["-"], "fdiagnostics-show-template-tree">,
     Group<f_Group>, Flags<[CC1Option]>,

clang/lib/Driver/Driver.cpp

if (Args.hasFlag(options::OPT_foptimization_record_file_EQ,
     return true;
 
   // -foptimization-record-passes alone enables it too.
   if (Args.hasFlag(options::OPT_foptimization_record_passes_EQ,
                    options::OPT_fno_save_optimization_record, false))
     return true;
   return false;
 }
+
+bool clang::driver::hasRpassOptions(const ArgList &Args) {
+  // -Rpass=<format> enables it.
+  if (Args.getLastArg(options::OPT_Rpass_EQ))
+    return true;
+
+  // -Rpass-missed=<format> alone enables it too.
+  if (Args.getLastArg(options::OPT_Rpass_missed_EQ))
+    return true;
+
+  // -Rpass-analysis=<format> alone enables it too.
+  if (Args.getLastArg(options::OPT_Rpass_analysis_EQ))
+    return true;
+
+  return false;
+}

clang/lib/Driver/ToolChains/CommonArgs.cpp

 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/YAMLParser.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang;
 using namespace llvm::opt;
 
+// Remarks option pass-through only happens when
+// 1). single arch target
+// 2). linker is lld
+static bool checkRemarksOptions(StringRef LinkerPath, const ArgList &Args,
+                                const llvm::Triple &Triple) {
+  bool hasMultipleArchs =
+      Triple.isOSDarwin() && Args.getAllArgValues(options::OPT_arch).size() > 1;
+
+  bool isLLD = llvm::sys::path::filename(LinkerPath) == "ld.lld" ||
+               llvm::sys::path::stem(LinkerPath) != "ld.lld";
+  if (hasMultipleArchs || !isLLD)
+    return false;
+  return true;
+}
+
+static void renderRpassOptions(const ArgList &Args, ArgStringList &CmdArgs) {
+  if (const Arg *A = Args.getLastArg(options::OPT_Rpass_EQ)) {
+    CmdArgs.push_back("-mllvm");
+    std::string Passes = std::string("-pass-remarks=") + A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(Passes));
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_Rpass_missed_EQ)) {
+    CmdArgs.push_back("-mllvm");
+    std::string Passes = std::string("-pass-remarks-missed=") + A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(Passes));
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_Rpass_analysis_EQ)) {
+    CmdArgs.push_back("-mllvm");
+    std::string Passes = std::string("-pass-remarks-analysis=") + A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(Passes));
+  }
+}
+
+static void renderRemarksOptions(const ArgList &Args, ArgStringList &CmdArgs,
+                                 const llvm::Triple &Triple,
+                                 const InputInfo &Input,
+                                 const InputInfo &Output) {
+  StringRef Format = "yaml";
+  if (const Arg *A = Args.getLastArg(options::OPT_fsave_optimization_record_EQ))
+    Format = A->getValue();
+
+  CmdArgs.push_back("--opt-remarks-filename");
+
+  SmallString<128> F;
+  const Arg *A = Args.getLastArg(options::OPT_foptimization_record_file_EQ);
+  if (A) {
+    F = A->getValue();
+  } else {
+    if (Output.isFilename())
+      F = Output.getFilename();
+
+    if (F.empty()) {
+      // Use the input filename.
+      F = llvm::sys::path::stem(Input.getBaseInput());
+    }
+  }
+  // Append "opt.ld.<format>" to the end of the file name.
+  SmallString<32> Extension;
+  Extension += ".opt.ld.";
+  Extension += Format;
+
+  CmdArgs.push_back(Args.MakeArgString(F + Extension));
+
+  if (const Arg *A =
+          Args.getLastArg(options::OPT_foptimization_record_passes_EQ)) {
+    CmdArgs.push_back("--opt-remarks-passes");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  CmdArgs.push_back("--opt-remarks-format");
+  CmdArgs.push_back(Format.data());
+}
+
+static void renderRemarksHotnessOptions(const ArgList &Args,
+                                        ArgStringList &CmdArgs) {
+  if (Args.hasFlag(options::OPT_fdiagnostics_show_hotness,
+                   options::OPT_fno_diagnostics_show_hotness, false))
+    CmdArgs.push_back("--opt-remarks-with-hotness");
+
+  if (const Arg *A =
+          Args.getLastArg(options::OPT_fdiagnostics_hotness_threshold_EQ)) {
+    std::string Opt =
+        std::string("--opt-remarks-hotness-threshold=") + A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(Opt));
+  }
+}
+
 void tools::addPathIfExists(const Driver &D, const Twine &Path,
                             ToolChain::path_list &Paths) {
   if (D.getVFS().exists(Path))
     Paths.push_back(Path.str());
 }
 
 void tools::handleTargetFeaturesGroup(const ArgList &Args,
                                       std::vector<StringRef> &Features,
#endif
 
   // Setup statistics file output.
   SmallString<128> StatsFile = getStatsFileName(Args, Output, Input, D);
   if (!StatsFile.empty())
     CmdArgs.push_back(
         Args.MakeArgString(Twine("-plugin-opt=stats-file=") + StatsFile));
 
   addX86AlignBranchArgs(D, Args, CmdArgs, /*IsLTO=*/true);
+
+  if (checkRemarksOptions(Linker, Args, ToolChain.getEffectiveTriple())) {
+    // handle remark diagnostics on screen options: '-Rpass-*'
+    if (hasRpassOptions(Args)) {
+      renderRpassOptions(Args, CmdArgs);
+    }
+
+    // handle serialized remarks options: '-fsave-optimization-record'
+    // and '-foptimization-record-*'
+    if (willEmitRemarks(Args)) {
+      renderRemarksOptions(Args, CmdArgs, ToolChain.getEffectiveTriple(), Input,
+                           Output);
+    }
+
+    // handle remarks hotness/threshold related options
+    renderRemarksHotnessOptions(Args, CmdArgs);
+  }
 }
 
 void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
                                  ArgStringList &CmdArgs) {
   // Enable -frtlib-add-rpath by default for the case of VE.
   const bool IsVE = TC.getTriple().isVE();
   bool DefaultValue = IsVE;
   if (!Args.hasFlag(options::OPT_frtlib_add_rpath,

clang/lib/Frontend/CompilerInvocation.cpp

 //===- CompilerInvocation.cpp ---------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/Frontend/CompilerInvocation.h"
 #include "TestModuleFileExtension.h"
 #include "clang/Basic/Builtins.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/CommentOptions.h"
 #include "clang/Basic/DebugInfoOptions.h"
 #include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticDriver.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/LangStandard.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/SourceLocation.h"

 #include "llvm/Linker/Linker.h"
 #include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptSpecifier.h"
 #include "llvm/Option/OptTable.h"
 #include "llvm/Option/Option.h"
 #include "llvm/ProfileData/InstrProfReader.h"
+#include "llvm/Remarks/HotnessThresholdParser.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MathExtras.h"
bool UsingProfile = UsingSampleProfile ||
       (Opts.getProfileUse() != CodeGenOptions::ProfileNone);
 
   if (Opts.DiagnosticsWithHotness && !UsingProfile &&
       // An IR file will contain PGO as metadata
       IK.getLanguage() != Language::LLVM_IR)
     Diags.Report(diag::warn_drv_diagnostics_hotness_requires_pgo)
         << "-fdiagnostics-show-hotness";
 
-  Opts.DiagnosticsHotnessThreshold = getLastArgUInt64Value(
-      Args, options::OPT_fdiagnostics_hotness_threshold_EQ, 0);
-  if (Opts.DiagnosticsHotnessThreshold > 0 && !UsingProfile)
+  // Parse remarks hotness threshold. Valid value is either integer or 'auto'.
+  if (auto *arg =
+          Args.getLastArg(options::OPT_fdiagnostics_hotness_threshold_EQ)) {
+    auto ResultOrErr =
+        llvm::remarks::parseHotnessThresholdOption(arg->getValue());
+
+    if (!ResultOrErr) {
+      Diags.Report(diag::err_drv_invalid_diagnotics_hotness_threshold)
+          << "-fdiagnostics-hotness-threshold=";
+    } else {
+      Opts.DiagnosticsHotnessThreshold = *ResultOrErr;
+      if ((!Opts.DiagnosticsHotnessThreshold.hasValue() ||
+           Opts.DiagnosticsHotnessThreshold.getValue() > 0) &&
+          !UsingProfile)
         Diags.Report(diag::warn_drv_diagnostics_hotness_requires_pgo)
             << "-fdiagnostics-hotness-threshold=";
+    }
+  }
 
   // If the user requested to use a sample profile for PGO, then the
   // backend will need to track source location information so the profile
   // can be incorporated into the IR.
   if (UsingSampleProfile)
     NeedLocTracking = true;
 
   // If the user requested a flag that requires source locations available in

clang/test/Driver/remarks-pass-through.c

+// This test verifies remarks options pass-through into linker(lld)
+
+// no pass-through if lto is disabled
+// RUN: %clang -### -o FOO -fdiagnostics-hotness-threshold=auto -fsave-optimization-record %s 2>&1 | not FileCheck %s
+
+// no pass-through if linker is not lld
+// RUN: %clang -### -o FOO -fuse-ld=gold -fdiagnostics-hotness-threshold=auto -fsave-optimization-record %s 2>&1 | not FileCheck %s
+
+// pass-through cases
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto -fdiagnostics-hotness-threshold=100 -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto -fdiagnostics-hotness-threshold=100 -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-MANUAL
+
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto -fdiagnostics-hotness-threshold=auto -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto -fdiagnostics-hotness-threshold=auto -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-AUTO
+//
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=auto -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=auto -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-AUTO
+//
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=auto -fsave-optimization-record=some-format -foptimization-record-file=FOO.txt %s 2>&1 | FileCheck %s -check-prefix=CHECK-CUSTOM
+//
+// RUN: %clang -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=auto -Rpass=inline -Rpass-missed=inline -Rpass-analysis=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-RPASS
+//
+// CHECK: "--opt-remarks-filename" "FOO.opt.ld.yaml"
+// CHECK: "--opt-remarks-passes" "inline"
+// CHECK: "--opt-remarks-format" "yaml"
+//
+// CHECK-MANUAL: "--opt-remarks-hotness-threshold=100"
+//
+// CHECK-AUTO: "--opt-remarks-hotness-threshold=auto"
+//
+// CHECK-CUSTOM: "--opt-remarks-filename" "FOO.txt.opt.ld.some-format"
+// CHECK-CUSTOM: "--opt-remarks-format" "some-format"
+// CHECK-CUSTOM: "--opt-remarks-hotness-threshold=auto"
+//
+// CHECK-RPASS: "-mllvm" "-pass-remarks=inline"
+// CHECK-RPASS: "-mllvm" "-pass-remarks-missed=inline"
+// CHECK-RPASS: "-mllvm" "-pass-remarks-analysis=inline"
+// CHECK-RPASS: "--opt-remarks-hotness-threshold=auto"

lld/ELF/Config.h

struct Configuration {
   uint64_t zStackSize;
   unsigned ltoPartitions;
   unsigned ltoo;
   unsigned optimize;
   StringRef thinLTOJobs;
   unsigned timeTraceGranularity;
   int32_t splitStackAdjustSize;
 
+  // The minimum hotness value a diagnostic needs in order to be included in
+  // optimization diagnostics.
+  //
+  // The threshold is an Optional value, which maps to one of the 3 states:
+  // 1. 0            => threshold disabled. All emarks will be printed.
+  // 2. positive int => manual threshold by user. Remarks with hotness exceed
+  //                    threshold will be printed.
+  // 3. None         => 'auto' threshold by user. The actual value is not
+  //                    available at command line, but will be synced with
+  //                    hotness threhold from profile summary during
+  //                    compilation.
+  //
+  // If threshold option is not specified, it is disabled by default.
+  llvm::Optional<uint64_t> optRemarksHotnessThreshold = 0;
+
   // The following config options do not directly correspond to any
   // particular command line options.
 
   // True if we need to pass through relocations in input files to the
   // output file. Usually false because we consume relocations.
   bool copyRelocs;
 
   // True if the target is ELF64. False if ELF32.

lld/ELF/Driver.cpp

 #include "lld/Common/Memory.h"
 #include "lld/Common/Strings.h"
 #include "lld/Common/TargetOptionsCommandFlags.h"
 #include "lld/Common/Version.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/LTO/LTO.h"
+#include "llvm/Remarks/HotnessThresholdParser.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/GlobPattern.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/Parallel.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
static void readConfigs(opt::InputArgList &args) {
   config->mmapOutputFile =
       args.hasFlag(OPT_mmap_output_file, OPT_no_mmap_output_file, true);
   config->nmagic = args.hasFlag(OPT_nmagic, OPT_no_nmagic, false);
   config->noinhibitExec = args.hasArg(OPT_noinhibit_exec);
   config->nostdlib = args.hasArg(OPT_nostdlib);
   config->oFormatBinary = isOutputFormatBinary(args);
   config->omagic = args.hasFlag(OPT_omagic, OPT_no_omagic, false);
   config->optRemarksFilename = args.getLastArgValue(OPT_opt_remarks_filename);
+  // Parse remarks hotness threshold. Valid value is either integer or 'auto'.
+  if (auto *arg = args.getLastArg(OPT_opt_remarks_hotness_threshold)) {
+    auto resultOrErr = remarks::parseHotnessThresholdOption(arg->getValue());
+    if (!resultOrErr) {
+      error(arg->getSpelling() + ": invalid argument '" + arg->getValue() +
+            "', only integer or 'auto' is supported.");
+    } else {
+      config->optRemarksHotnessThreshold = *resultOrErr;
+    }
+  }
   config->optRemarksPasses = args.getLastArgValue(OPT_opt_remarks_passes);
   config->optRemarksWithHotness = args.hasArg(OPT_opt_remarks_with_hotness);
   config->optRemarksFormat = args.getLastArgValue(OPT_opt_remarks_format);
   config->optimize = args::getInteger(args, OPT_O, 1);
   config->orphanHandling = getOrphanHandling(args);
   config->outputFile = args.getLastArgValue(OPT_o);
   config->pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
   config->printIcfSections =

lld/ELF/LTO.cpp

static lto::Config createConfig() {
   // Set up a custom pipeline if we've been asked to.
   c.OptPipeline = std::string(config->ltoNewPmPasses);
   c.AAPipeline = std::string(config->ltoAAPipeline);
 
   // Set up optimization remarks if we've been asked to.
   c.RemarksFilename = std::string(config->optRemarksFilename);
   c.RemarksPasses = std::string(config->optRemarksPasses);
   c.RemarksWithHotness = config->optRemarksWithHotness;
+  c.RemarksHotnessThreshold = config->optRemarksHotnessThreshold;
   c.RemarksFormat = std::string(config->optRemarksFormat);
 
   c.SampleProfile = std::string(config->ltoSampleProfile);
   c.UseNewPM = config->ltoNewPassManager;
   c.DebugPassManager = config->ltoDebugPassManager;
   c.DwoDir = std::string(config->dwoDir);
 
   c.HasWholeProgramVisibility = config->ltoWholeProgramVisibility;

lld/ELF/Options.td

 def lto_sample_profile: JJ<"lto-sample-profile=">,
   HelpText<"Sample profile file path">;
 def lto_whole_program_visibility: FF<"lto-whole-program-visibility">,
   HelpText<"Asserts that the LTO link has whole program visibility">;
 def disable_verify: F<"disable-verify">;
 defm mllvm: Eq<"mllvm", "Additional arguments to forward to LLVM's option processing">;
 def opt_remarks_filename: Separate<["--"], "opt-remarks-filename">,
   HelpText<"YAML output file for optimization remarks">;
+defm opt_remarks_hotness_threshold: EEq<"opt-remarks-hotness-threshold",
+  "Minimum profile count required for an optimization remark to be output."
+  " Use 'auto' to apply the threshold from profile summary.">,
+  MetaVarName<"<value>">;
 def opt_remarks_passes: Separate<["--"], "opt-remarks-passes">,
   HelpText<"Regex for the passes that need to be serialized to the output file">;
 def opt_remarks_with_hotness: FF<"opt-remarks-with-hotness">,
   HelpText<"Include hotness information in the optimization remarks file">;
 def opt_remarks_format: Separate<["--"], "opt-remarks-format">,
   HelpText<"The format used for serializing remarks (default: YAML)">;
 def save_temps: F<"save-temps">;
 def lto_basicblock_sections: JJ<"lto-basicblock-sections=">,

lld/test/ELF/lto/opt-remarks.ll

 ; REQUIRES: x86
 ; RUN: llvm-as %s -o %t.o
 
-; RUN: rm -f %t.yaml
+; RUN: rm -f %t.yaml %t1.yaml %t.hot.yaml %t.t300.yaml %t.t301.yaml
 ; RUN: ld.lld --opt-remarks-filename %t.yaml %t.o -o %t -shared -save-temps
 ; RUN: llvm-dis %t.0.4.opt.bc -o - | FileCheck %s
 ; RUN: ld.lld --opt-remarks-with-hotness --opt-remarks-filename %t.hot.yaml \
 ; RUN:  %t.o -o %t -shared
+; RUN: ld.lld --opt-remarks-with-hotness --opt-remarks-hotness-threshold=300 \
+; RUN: --opt-remarks-filename %t.t300.yaml %t.o -o %t -shared
+; RUN: ld.lld --opt-remarks-with-hotness --opt-remarks-hotness-threshold=301 \
+; RUN: --opt-remarks-filename %t.t301.yaml %t.o -o %t -shared
 ; RUN: cat %t.yaml | FileCheck %s -check-prefix=YAML
 ; RUN: cat %t.hot.yaml | FileCheck %s -check-prefix=YAML-HOT
+; RUN: cat %t.t300.yaml | FileCheck %s -check-prefix=YAML-HOT
+; RUN: count 0 < %t.t301.yaml
 ; RUN: ld.lld --opt-remarks-filename %t1.yaml --opt-remarks-passes inline %t.o \
 ; RUN: -o /dev/null -shared
 ; RUN: cat %t1.yaml | FileCheck %s -check-prefix=YAML-PASSES
 ; RUN: ld.lld --opt-remarks-filename %t1.yaml --opt-remarks-format yaml %t.o \
 ; RUN: -o /dev/null -shared
-; RUN: cat %t.yaml | FileCheck %s -check-prefix=YAML
+; RUN: cat %t1.yaml | FileCheck %s -check-prefix=YAML
 
 ; Check that @tinkywinky is inlined after optimizations.
 ; CHECK-LABEL: define i32 @main
 ; CHECK-NEXT:  %a.i = {{.*}}call i32 @patatino()
 ; CHECK-NEXT:  ret i32 %a.i
 ; CHECK-NEXT: }
 
 ; YAML:      --- !Passed

llvm/include/llvm/Analysis/ProfileSummaryInfo.h

 /// isColdCount that tells whether a given profile count is considered hot/cold
 /// based on the profile summary. This also provides convenience methods to
 /// check whether a function is hot or cold.
 
 // FIXME: Provide convenience methods to determine hotness/coldness of other IR
 // units. This would require making this depend on BFI.
 class ProfileSummaryInfo {
 private:
-  Module &M;
+  const Module &M;
   std::unique_ptr<ProfileSummary> Summary;
   void computeThresholds();
   // Count thresholds to answer isHotCount and isColdCount queries.
   Optional<uint64_t> HotCountThreshold, ColdCountThreshold;
   // True if the working set size of the code is considered huge,
   // because the number of profile counts required to reach the hot
   // percentile is above a huge threshold.
   Optional<bool> HasHugeWorkingSetSize;
   // True if the working set size of the code is considered large,
   // because the number of profile counts required to reach the hot
   // percentile is above a large threshold.
   Optional<bool> HasLargeWorkingSetSize;
   // Compute the threshold for a given cutoff.
   Optional<uint64_t> computeThreshold(int PercentileCutoff) const;
   // The map that caches the threshold values. The keys are the percentile
   // cutoff values and the values are the corresponding threshold values.
   mutable DenseMap<int, uint64_t> ThresholdCache;
 
 public:
-  ProfileSummaryInfo(Module &M) : M(M) { refresh(); }
+  ProfileSummaryInfo(const Module &M) : M(M) { refresh(); }
+
   ProfileSummaryInfo(ProfileSummaryInfo &&Arg) = default;
 
   /// If no summary is present, attempt to refresh.
   void refresh();
 
   /// Returns true if profile summary is available.
   bool hasProfileSummary() const { return Summary != nullptr; }
 

llvm/include/llvm/IR/LLVMContext.h

#undef LLVM_FIXED_MD_KIND
   /// Return if a code hotness metric should be included in optimization
   /// diagnostics.
   bool getDiagnosticsHotnessRequested() const;
   /// Set if a code hotness metric should be included in optimization
   /// diagnostics.
   void setDiagnosticsHotnessRequested(bool Requested);
 
   /// Return the minimum hotness value a diagnostic would need in order
-  /// to be included in optimization diagnostics. If there is no minimum, this
-  /// returns None.
+  /// to be included in optimization diagnostics.
+  ///
+  /// Three possible return values:
+  /// 0            - threshold is disabled. Everything will be printed out.
+  /// positive int - threshold is set.
+  /// UINT64_MAX   - threshold is not yet set, and needs to be synced from
+  ///                profile summary. Note that in case of missing profile
+  ///                summary, threshold will be kept at "MAX", effectively
+  ///                suppresses all remarks output.
   uint64_t getDiagnosticsHotnessThreshold() const;
 
   /// Set the minimum hotness value a diagnostic needs in order to be
   /// included in optimization diagnostics.
-  void setDiagnosticsHotnessThreshold(uint64_t Threshold);
+  void setDiagnosticsHotnessThreshold(Optional<uint64_t> Threshold);
+
+  /// Return if hotness threshold is requested from PSI.
+  bool isDiagnosticsHotnessThresholdSetFromPSI() const;
 
   /// The "main remark streamer" used by all the specialized remark streamers.
   /// This streamer keeps generic remark metadata in memory throughout the life
   /// of the LLVMContext. This metadata may be emitted in a section in object
   /// files depending on the format requirements.
   ///
   /// All specialized remark streamers should convert remarks to
   /// llvm::remarks::Remark and emit them through this streamer.

llvm/include/llvm/IR/LLVMRemarkStreamer.h

using LLVMRemarkSetupErrorInfo<
       LLVMRemarkSetupFormatError>::LLVMRemarkSetupErrorInfo;
 };
 
 /// Setup optimization remarks that output to a file.
 Expected<std::unique_ptr<ToolOutputFile>>
 setupLLVMOptimizationRemarks(LLVMContext &Context, StringRef RemarksFilename,
                              StringRef RemarksPasses, StringRef RemarksFormat,
                              bool RemarksWithHotness,
-                             unsigned RemarksHotnessThreshold = 0);
+                             Optional<uint64_t> RemarksHotnessThreshold = 0);
 
 /// Setup optimization remarks that output directly to a raw_ostream.
 /// \p OS is managed by the caller and should be open for writing as long as \p
 /// Context is streaming remarks to it.
-Error setupLLVMOptimizationRemarks(LLVMContext &Context, raw_ostream &OS,
-                                   StringRef RemarksPasses,
-                                   StringRef RemarksFormat,
-                                   bool RemarksWithHotness,
-                                   unsigned RemarksHotnessThreshold = 0);
+Error setupLLVMOptimizationRemarks(
+    LLVMContext &Context, raw_ostream &OS, StringRef RemarksPasses,
+    StringRef RemarksFormat, bool RemarksWithHotness,
+    Optional<uint64_t> RemarksHotnessThreshold = 0);
 
 } // end namespace llvm
 
 #endif // LLVM_IR_LLVMREMARKSTREAMER_H

llvm/include/llvm/IR/Module.h

/// @}
   /// @name Utility functions for querying and setting PGO summary
   /// @{
 
   /// Attach profile summary metadata to this module.
   void setProfileSummary(Metadata *M, ProfileSummary::Kind Kind);
 
   /// Returns profile summary metadata. When IsCS is true, use the context
   /// sensitive profile summary.
-  Metadata *getProfileSummary(bool IsCS);
+  Metadata *getProfileSummary(bool IsCS) const;
   /// @}
 
   /// Returns whether semantic interposition is to be respected.
   bool getSemanticInterposition() const;
   bool noSemanticInterposition() const;
 
   /// Set whether semantic interposition is to be respected.
   void setSemanticInterposition(bool);

llvm/include/llvm/LTO/Config.h

struct Config {
   std::string RemarksFilename = "";
 
   /// Optimization remarks pass filter.
   std::string RemarksPasses = "";
 
   /// Whether to emit optimization remarks with hotness informations.
   bool RemarksWithHotness = false;
 
+  /// The minimum hotness value a diagnostic needs in order to be included in
+  /// optimization diagnostics.
+  ///
+  /// The threshold is an Optional value, which maps to one of the 3 states:
+  /// 1. 0            => threshold disabled. All emarks will be printed.
+  /// 2. positive int => manual threshold by user. Remarks with hotness exceed
+  ///                    threshold will be printed.
+  /// 3. None         => 'auto' threshold by user. The actual value is not
+  ///                    available at command line, but will be synced with
+  ///                    hotness threhold from profile summary during
+  ///                    compilation.
+  ///
+  /// If threshold option is not specified, it is disabled by default.
+  llvm::Optional<uint64_t> RemarksHotnessThreshold = 0;
+
   /// The format used for serializing remarks (default: YAML).
   std::string RemarksFormat = "";
 
   /// Whether to emit the pass manager debuggging informations.
   bool DebugPassManager = false;
 
   /// Statistics output file path.
   std::string StatsFile;

llvm/include/llvm/LTO/LTO.h

 /// Given the original \p Path to an output file, replace any path
 /// prefix matching \p OldPrefix with \p NewPrefix. Also, create the
 /// resulting directory if it does not yet exist.
 std::string getThinLTOOutputFile(const std::string &Path,
                                  const std::string &OldPrefix,
                                  const std::string &NewPrefix);
 
 /// Setup optimization remarks.
-Expected<std::unique_ptr<ToolOutputFile>>
-setupLLVMOptimizationRemarks(LLVMContext &Context, StringRef RemarksFilename,
-                             StringRef RemarksPasses, StringRef RemarksFormat,
-                             bool RemarksWithHotness, int Count = -1);
+Expected<std::unique_ptr<ToolOutputFile>> setupLLVMOptimizationRemarks(
+    LLVMContext &Context, StringRef RemarksFilename, StringRef RemarksPasses,
+    StringRef RemarksFormat, bool RemarksWithHotness,
+    Optional<uint64_t> RemarksHotnessThreshold = 0, int Count = -1);
 
 /// Setups the output file for saving statistics.
 Expected<std::unique_ptr<ToolOutputFile>>
 setupStatsFile(StringRef StatsFilename);
 
 class LTO;
 struct SymbolResolution;
 class ThinBackendProc;

llvm/include/llvm/Remarks/HotnessThresholdParser.h

+//===- HotnessThresholdParser.h - Parser for hotness threshold --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// @file
+/// This file implements a simple parser to decode commandline option for
+/// remarks hotness threshold.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_REMARKS_HOTNESSTHRESHOLDPARSER_H
+#define LLVM_REMARKS_HOTNESSTHRESHOLDPARSER_H
+
+#include "llvm/ADT/Optional.h"
+#include "llvm/Support/CommandLine.h"
+namespace llvm {
+namespace remarks {
+
+// Parse remarks hotness threshold argument value.
+// Valid option values is
+// 1. integer: manually specified threshold; or
+// 2. string 'auto': automatically get threshold from profile summary
+//
+// Return None Optional if 'auto' is specified, indicating the value will
+// be filled later during PSI.
+inline Expected<Optional<uint64_t>> parseHotnessThresholdOption(StringRef Arg) {
+  if (Arg == "auto") {
+    return None;
+  }
+
+  int64_t Val;
+  if (Arg.getAsInteger(10, Val)) {
+    return createStringError(llvm::inconvertibleErrorCode(),
+                             "Not an integer: %s", Arg.data());
+  }
+
+  // Negative integer effectively means no threshold
+  return Val < 0 ? 0 : Val;
+}
+
+// A simple CL parser for '-pass-remarks-hotness-threshold='
+class HotnessThresholdParser : public cl::parser<Optional<uint64_t>> {
+public:
+  HotnessThresholdParser(cl::Option &O) : cl::parser<Optional<uint64_t>>(O) {}
+
+  bool parse(cl::Option &O, StringRef ArgName, StringRef Arg,
+             Optional<uint64_t> &V) {
+    auto ResultOrErr = parseHotnessThresholdOption(Arg);
+    if (!ResultOrErr) {
+      return O.error("Invalid argument '" + Arg +
+                     "', only integer or 'auto' is supported.");
+    }
+
+    V = *ResultOrErr;
+    return false;
+  }
+};
+
+} // namespace remarks
+} // namespace llvm
+#endif // LLVM_REMARKS_HOTNESSTHRESHOLDPARSER_H

llvm/lib/Analysis/OptimizationRemarkEmitter.cpp

 // that by using this service passes become dependent on BFI as well.  BFI is
 // used to compute the "hotness" of the diagnostic message.
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/LazyBlockFrequencyInfo.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/InitializePasses.h"
 
 using namespace llvm;
 
 OptimizationRemarkEmitter::OptimizationRemarkEmitter(const Function *F)
OptimizationRemarkEmitterWrapperPass::OptimizationRemarkEmitterWrapperPass()
     : FunctionPass(ID) {
   initializeOptimizationRemarkEmitterWrapperPassPass(
       *PassRegistry::getPassRegistry());
 }
 
 bool OptimizationRemarkEmitterWrapperPass::runOnFunction(Function &Fn) {
   BlockFrequencyInfo *BFI;
 
-  if (Fn.getContext().getDiagnosticsHotnessRequested())
+  auto &Context = Fn.getContext();
+  if (Context.getDiagnosticsHotnessRequested()) {
     BFI = &getAnalysis<LazyBlockFrequencyInfoPass>().getBFI();
-  else
+    // Get hotness threshold from PSI. This should only happen once.
+    if (Context.isDiagnosticsHotnessThresholdSetFromPSI()) {
+      if (ProfileSummaryInfo *PSI =
+              &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI())
+        Context.setDiagnosticsHotnessThreshold(
+            PSI->getOrCompHotCountThreshold());
+    }
+  } else
     BFI = nullptr;
 
   ORE = std::make_unique<OptimizationRemarkEmitter>(&Fn, BFI);
   return false;
 }
 
 void OptimizationRemarkEmitterWrapperPass::getAnalysisUsage(
     AnalysisUsage &AU) const {
   LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AU);
   AU.setPreservesAll();
 }
 
 AnalysisKey OptimizationRemarkEmitterAnalysis::Key;
 
 OptimizationRemarkEmitter
 OptimizationRemarkEmitterAnalysis::run(Function &F,
                                        FunctionAnalysisManager &AM) {
   BlockFrequencyInfo *BFI;
+  auto &Context = F.getContext();
 
-  if (F.getContext().getDiagnosticsHotnessRequested())
+  if (Context.getDiagnosticsHotnessRequested()) {
     BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
-  else
+    // Get hotness threshold from PSI. This should only happen once.
+    if (Context.isDiagnosticsHotnessThresholdSetFromPSI()) {
+      auto &MAMProxy = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
+      if (ProfileSummaryInfo *PSI =
+              MAMProxy.getCachedResult<ProfileSummaryAnalysis>(*F.getParent()))
+        Context.setDiagnosticsHotnessThreshold(
+            PSI->getOrCompHotCountThreshold());
+    }
+  } else
     BFI = nullptr;
 
   return OptimizationRemarkEmitter(&F, BFI);
 }
 
 char OptimizationRemarkEmitterWrapperPass::ID = 0;
 static const char ore_name[] = "Optimization Remark Emitter";
 #define ORE_NAME "opt-remark-emitter"
 
 INITIALIZE_PASS_BEGIN(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,
                       false, true)
 INITIALIZE_PASS_DEPENDENCY(LazyBFIPass)
+INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
 INITIALIZE_PASS_END(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,
                     false, true)

llvm/lib/IR/LLVMContext.cpp

 
 void LLVMContext::setDiagnosticsHotnessRequested(bool Requested) {
   pImpl->DiagnosticsHotnessRequested = Requested;
 }
 bool LLVMContext::getDiagnosticsHotnessRequested() const {
   return pImpl->DiagnosticsHotnessRequested;
 }
 
-void LLVMContext::setDiagnosticsHotnessThreshold(uint64_t Threshold) {
+void LLVMContext::setDiagnosticsHotnessThreshold(Optional<uint64_t> Threshold) {
   pImpl->DiagnosticsHotnessThreshold = Threshold;
 }
+
 uint64_t LLVMContext::getDiagnosticsHotnessThreshold() const {
-  return pImpl->DiagnosticsHotnessThreshold;
+  return pImpl->DiagnosticsHotnessThreshold.getValueOr(UINT64_MAX);
+}
+
+bool LLVMContext::isDiagnosticsHotnessThresholdSetFromPSI() const {
+  return !pImpl->DiagnosticsHotnessThreshold.hasValue();
 }
 
 remarks::RemarkStreamer *LLVMContext::getMainRemarkStreamer() {
   return pImpl->MainRemarkStreamer.get();
 }
 const remarks::RemarkStreamer *LLVMContext::getMainRemarkStreamer() const {
   return const_cast<LLVMContext *>(this)->getMainRemarkStreamer();
 }

llvm/lib/IR/LLVMContextImpl.h

public:
   /// The main remark streamer used by all the other streamers (e.g. IR, MIR,
   /// frontends, etc.). This should only be used by the specific streamers, and
   /// never directly.
   std::unique_ptr<remarks::RemarkStreamer> MainRemarkStreamer;
 
   std::unique_ptr<DiagnosticHandler> DiagHandler;
   bool RespectDiagnosticFilters = false;
   bool DiagnosticsHotnessRequested = false;
-  uint64_t DiagnosticsHotnessThreshold = 0;
+  /// The minimum hotness value a diagnostic needs in order to be included in
+  /// optimization diagnostics.
+  ///
+  /// The threshold is an Optional value, which maps to one of the 3 states:
+  /// 1). 0            => threshold disabled. All emarks will be printed.
+  /// 2). positive int => manual threshold by user. Remarks with hotness exceed
+  ///                     threshold will be printed.
+  /// 3). None         => 'auto' threshold by user. The actual value is not
+  ///                     available at command line, but will be synced with
+  ///                     hotness threhold from profile summary during
+  ///                     compilation.
+  ///
+  /// State 1 and 2 are considered as terminal states. State transition is
+  /// only allowed from 3 to 2, when the threshold is first synced with profile
+  /// summary. This ensures that the threshold is set only once and stays
+  /// constant.
+  ///
+  /// If threshold option is not specified, it is disabled (0) by default.
+  Optional<uint64_t> DiagnosticsHotnessThreshold = 0;
+
   /// The specialized remark streamer used by LLVM's OptimizationRemarkEmitter.
   std::unique_ptr<LLVMRemarkStreamer> LLVMRS;
 
   LLVMContext::YieldCallbackTy YieldCallback = nullptr;
   void *YieldOpaqueHandle = nullptr;
 
   using IntMapTy =
       DenseMap<APInt, std::unique_ptr<ConstantInt>, DenseMapAPIntKeyInfo>;

llvm/lib/IR/LLVMRemarkStreamer.cpp

 
 char LLVMRemarkSetupFileError::ID = 0;
 char LLVMRemarkSetupPatternError::ID = 0;
 char LLVMRemarkSetupFormatError::ID = 0;
 
 Expected<std::unique_ptr<ToolOutputFile>> llvm::setupLLVMOptimizationRemarks(
     LLVMContext &Context, StringRef RemarksFilename, StringRef RemarksPasses,
     StringRef RemarksFormat, bool RemarksWithHotness,
-    unsigned RemarksHotnessThreshold) {
+    Optional<uint64_t> RemarksHotnessThreshold) {
   if (RemarksWithHotness)
     Context.setDiagnosticsHotnessRequested(true);
 
-  if (RemarksHotnessThreshold)
-    Context.setDiagnosticsHotnessThreshold(RemarksHotnessThreshold);
 
   if (RemarksFilename.empty())
     return nullptr;
 
   Expected<remarks::Format> Format = remarks::parseFormat(RemarksFormat);
   if (Error E = Format.takeError())
     return make_error<LLVMRemarkSetupFormatError>(std::move(E));
 
Expected<std::unique_ptr<ToolOutputFile>> llvm::setupLLVMOptimizationRemarks(
 
   if (!RemarksPasses.empty())
     if (Error E = Context.getMainRemarkStreamer()->setFilter(RemarksPasses))
       return make_error<LLVMRemarkSetupPatternError>(std::move(E));
 
   return std::move(RemarksFile);
 }
 
-Error llvm::setupLLVMOptimizationRemarks(LLVMContext &Context, raw_ostream &OS,
-                                         StringRef RemarksPasses,
-                                         StringRef RemarksFormat,
-                                         bool RemarksWithHotness,
-                                         unsigned RemarksHotnessThreshold) {
+Error llvm::setupLLVMOptimizationRemarks(
+    LLVMContext &Context, raw_ostream &OS, StringRef RemarksPasses,
+    StringRef RemarksFormat, bool RemarksWithHotness,
+    Optional<uint64_t> RemarksHotnessThreshold) {
   if (RemarksWithHotness)
     Context.setDiagnosticsHotnessRequested(true);
 
-  if (RemarksHotnessThreshold)
-    Context.setDiagnosticsHotnessThreshold(RemarksHotnessThreshold);
 
   Expected<remarks::Format> Format = remarks::parseFormat(RemarksFormat);
   if (Error E = Format.takeError())
     return make_error<LLVMRemarkSetupFormatError>(std::move(E));
 
   Expected<std::unique_ptr<remarks::RemarkSerializer>> RemarkSerializer =
       remarks::createRemarkSerializer(*Format,
                                       remarks::SerializerMode::Separate, OS);

llvm/lib/IR/Module.cpp

 
 void Module::setProfileSummary(Metadata *M, ProfileSummary::Kind Kind) {
   if (Kind == ProfileSummary::PSK_CSInstr)
     setModuleFlag(ModFlagBehavior::Error, "CSProfileSummary", M);
   else
     setModuleFlag(ModFlagBehavior::Error, "ProfileSummary", M);
 }
 
-Metadata *Module::getProfileSummary(bool IsCS) {
+Metadata *Module::getProfileSummary(bool IsCS) const {
   return (IsCS ? getModuleFlag("CSProfileSummary")
                : getModuleFlag("ProfileSummary"));
 }
 
 bool Module::getSemanticInterposition() const {
   Metadata *MF = getModuleFlag("SemanticInterposition");
 
   auto *Val = cast_or_null<ConstantAsMetadata>(MF);

llvm/lib/LTO/LTO.cpp

Error LTO::run(AddStreamFn AddStream, NativeObjectCache Cache) {
 
   return Result;
 }
 
 Error LTO::runRegularLTO(AddStreamFn AddStream) {
   // Setup optimization remarks.
   auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
       RegularLTO.CombinedModule->getContext(), Conf.RemarksFilename,
-      Conf.RemarksPasses, Conf.RemarksFormat, Conf.RemarksWithHotness);
+      Conf.RemarksPasses, Conf.RemarksFormat, Conf.RemarksWithHotness,
+      Conf.RemarksHotnessThreshold);
   if (!DiagFileOrErr)
     return DiagFileOrErr.takeError();
 
   // Finalize linking of regular LTO modules containing summaries now that
   // we have computed liveness information.
   for (auto &M : RegularLTO.ModsWithSummaries)
     if (Error Err = linkRegularLTO(std::move(M),
                                    /*LivenessFromIndex=*/true))
for (auto &Mod : ModuleMap) {
     ++Task;
   }
 
   return BackendProc->wait();
 }
 
 Expected<std::unique_ptr<ToolOutputFile>> lto::setupLLVMOptimizationRemarks(
     LLVMContext &Context, StringRef RemarksFilename, StringRef RemarksPasses,
-    StringRef RemarksFormat, bool RemarksWithHotness, int Count) {
+    StringRef RemarksFormat, bool RemarksWithHotness,
+    Optional<uint64_t> RemarksHotnessThreshold, int Count) {
   std::string Filename = std::string(RemarksFilename);
   // For ThinLTO, file.opt.<format> becomes
   // file.opt.<format>.thin.<num>.<format>.
   if (!Filename.empty() && Count != -1)
     Filename =
         (Twine(Filename) + ".thin." + llvm::utostr(Count) + "." + RemarksFormat)
             .str();
 
   auto ResultOrErr = llvm::setupLLVMOptimizationRemarks(
-      Context, Filename, RemarksPasses, RemarksFormat, RemarksWithHotness);
+      Context, Filename, RemarksPasses, RemarksFormat, RemarksWithHotness,
+      RemarksHotnessThreshold);
   if (Error E = ResultOrErr.takeError())
     return std::move(E);
 
   if (*ResultOrErr)
     (*ResultOrErr)->keep();
 
   return ResultOrErr;
 }

llvm/lib/LTO/LTOBackend.cpp

Error lto::thinBackend(const Config &Conf, unsigned Task, AddStreamFn AddStream,
   if (!TOrErr)
     return TOrErr.takeError();
 
   std::unique_ptr<TargetMachine> TM = createTargetMachine(Conf, *TOrErr, Mod);
 
   // Setup optimization remarks.
   auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
       Mod.getContext(), Conf.RemarksFilename, Conf.RemarksPasses,
-      Conf.RemarksFormat, Conf.RemarksWithHotness, Task);
+      Conf.RemarksFormat, Conf.RemarksWithHotness, Conf.RemarksHotnessThreshold,
+      Task);
   if (!DiagFileOrErr)
     return DiagFileOrErr.takeError();
   auto DiagnosticOutputFile = std::move(*DiagFileOrErr);
 
   // Set the partial sample profile ratio in the profile summary module flag of
   // the module, if applicable.
   Mod.setPartialSampleProfileRatio(CombinedIndex);
 

llvm/lib/LTO/LTOCodeGenerator.cpp

 #include "llvm/InitializePasses.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/LTO/legacy/LTOModule.h"
 #include "llvm/LTO/legacy/UpdateCompilerUsed.h"
 #include "llvm/Linker/Linker.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/SubtargetFeature.h"
+#include "llvm/Remarks/HotnessThresholdParser.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/ToolOutputFile.h"

 #endif
     cl::Hidden);
 
 cl::opt<bool> RemarksWithHotness(
     "lto-pass-remarks-with-hotness",
     cl::desc("With PGO, include profile count in optimization remarks"),
     cl::Hidden);
 
+cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser>
+    RemarksHotnessThreshold(
+        "lto-pass-remarks-hotness-threshold",
+        cl::desc("Minimum profile count required for an "
+                 "optimization remark to be output."
+                 " Use 'auto' to apply the threshold from profile summary."),
+        cl::value_desc("uint or 'auto'"), cl::init(Optional<uint64_t>(0)),
+        cl::Hidden);
+
 cl::opt<std::string>
     RemarksFilename("lto-pass-remarks-output",
                     cl::desc("Output filename for pass remarks"),
                     cl::value_desc("filename"));
 
 cl::opt<std::string>
     RemarksPasses("lto-pass-remarks-filter",
                   cl::desc("Only record optimization remarks from passes whose "

 
 /// Optimize merged modules using various IPO passes
 bool LTOCodeGenerator::optimize(bool DisableVerify, bool DisableInline,
                                 bool DisableGVNLoadPRE,
                                 bool DisableVectorization) {
   if (!this->determineTarget())
     return false;
 
-  auto DiagFileOrErr =
-      lto::setupLLVMOptimizationRemarks(Context, RemarksFilename, RemarksPasses,
-                                        RemarksFormat, RemarksWithHotness);
+  auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
+      Context, RemarksFilename, RemarksPasses, RemarksFormat,
+      RemarksWithHotness, RemarksHotnessThreshold);
   if (!DiagFileOrErr) {
     errs() << "Error: " << toString(DiagFileOrErr.takeError()) << "\n";
     report_fatal_error("Can't get an output file for the remarks");
   }
   DiagnosticOutputFile = std::move(*DiagFileOrErr);
 
   // Setup output file to emit statistics.
   auto StatsFileOrErr = lto::setupStatsFile(LTOStatsFile);

llvm/lib/LTO/ThinLTOCodeGenerator.cpp

 #define DEBUG_TYPE "thinlto"
 
 namespace llvm {
 // Flags -discard-value-names, defined in LTOCodeGenerator.cpp
 extern cl::opt<bool> LTODiscardValueNames;
 extern cl::opt<std::string> RemarksFilename;
 extern cl::opt<std::string> RemarksPasses;
 extern cl::opt<bool> RemarksWithHotness;
+extern cl::opt<Optional<uint64_t>> RemarksHotnessThreshold;
 extern cl::opt<std::string> RemarksFormat;
 }
 
 namespace {
 
 // Default to using all available threads in the system, but using only one
 // thred per core, as indicated by the usage of
 // heavyweight_hardware_concurrency() below.
for (auto IndexCount : ModulesOrdering) {
           }
         }
 
         LLVMContext Context;
         Context.setDiscardValueNames(LTODiscardValueNames);
         Context.enableDebugTypeODRUniquing();
         auto DiagFileOrErr = lto::setupLLVMOptimizationRemarks(
             Context, RemarksFilename, RemarksPasses, RemarksFormat,
-            RemarksWithHotness, count);
+            RemarksWithHotness, RemarksHotnessThreshold, count);
         if (!DiagFileOrErr) {
           errs() << "Error: " << toString(DiagFileOrErr.takeError()) << "\n";
           report_fatal_error("ThinLTO: Can't get an output file for the "
                              "remarks");
         }
 
         // Parse module now
         auto TheModule = loadModuleFromInput(Mod.get(), Context, false,

llvm/test/LTO/X86/diagnostic-handler-remarks-with-hotness.ll

 ; Check that the hotness attribute is included in the optimization record file
 ; with -lto-pass-remarks-with-hotness.
 
 ; RUN: llvm-as < %s >%t.bc
-; RUN: rm -f %t.yaml
+; RUN: rm -f %t.yaml %t.t300.yaml %t.t301.yaml
 ; RUN: llvm-lto -lto-pass-remarks-output=%t.yaml \
 ; RUN:          -lto-pass-remarks-with-hotness \
 ; RUN:          -exported-symbol _main -o %t.o %t.bc
 ; RUN: cat %t.yaml | FileCheck -check-prefix=YAML %s
 
+; RUN: llvm-lto -lto-pass-remarks-output=%t.t300.yaml \
+; RUN:          -lto-pass-remarks-with-hotness \
+; RUN:          -lto-pass-remarks-hotness-threshold=300 \
+; RUN:          -exported-symbol _main -o %t.o %t.bc
+; RUN: cat %t.t300.yaml | FileCheck -check-prefix=YAML %s
+
+; RUN: llvm-lto -lto-pass-remarks-output=%t.t301.yaml \
+; RUN:          -lto-pass-remarks-with-hotness \
+; RUN:          -lto-pass-remarks-hotness-threshold=301 \
+; RUN:          -exported-symbol _main -o %t.o %t.bc
+; RUN: cat %t.t301.yaml | not FileCheck -check-prefix=YAML %s
+
 ; YAML:      --- !Passed
 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: Function:        main
 ; YAML-NEXT: Hotness:         300
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee:          foo
 ; YAML-NEXT:   - String:          ' inlined into '

llvm/test/Other/optimization-remarks-auto.ll

+;; This test verifies 'auto' hotness threshold when profile summary is available.
+;;
+;; new PM
+; RUN: rm -f %t.yaml %t.hot.yaml
+; RUN: opt < %s --disable-output --enable-new-pm \
+; RUN: --passes='inline' \
+; RUN: --pass-remarks-output=%t.yaml --pass-remarks-filter='inline' \
+; RUN: --pass-remarks-with-hotness
+; RUN: FileCheck %s -check-prefix=YAML-PASS < %t.yaml
+; RUN: FileCheck %s -check-prefix=YAML-MISS < %t.yaml
+
+;; test 'auto' threshold
+; RUN: opt < %s --disable-output --enable-new-pm \
+; RUN: --passes='module(print-profile-summary,cgscc(inline))' \
+; RUN: --pass-remarks-output=%t.hot.yaml --pass-remarks-filter='inline' \
+; RUN: --pass-remarks-with-hotness --pass-remarks-hotness-threshold=auto 2>&1 | FileCheck %s
+; RUN: FileCheck %s -check-prefix=YAML-PASS < %t.hot.yaml
+; RUN: not FileCheck %s -check-prefix=YAML-MISS < %t.hot.yaml
+
+; RUN: opt < %s --disable-output --enable-new-pm \
+; RUN: --passes='module(print-profile-summary,cgscc(inline))' \
+; RUN: --pass-remarks=inline --pass-remarks-missed=inline --pass-remarks-analysis=inline \
+; RUN: --pass-remarks-with-hotness --pass-remarks-hotness-threshold=auto 2>&1 | FileCheck %s -check-prefix=CHECK-RPASS
+
+; YAML-PASS:      --- !Passed
+; YAML-PASS-NEXT: Pass:            inline
+; YAML-PASS-NEXT: Name:            Inlined
+; YAML-PASS-NEXT: Function:        caller1
+; YAML-PASS-NEXT: Hotness:         400
+
+; YAML-MISS:      --- !Missed
+; YAML-MISS-NEXT: Pass:            inline
+; YAML-MISS-NEXT: Name:            NeverInline
+; YAML-MISS-NEXT: Function:        caller2
+; YAML-MISS-NEXT: Hotness:         1
+
+; CHECK-RPASS: callee1 inlined into caller1 with (cost=-30, threshold=4500) (hotness: 400)
+; CHECK-RPASS-NOT: callee2 not inlined into caller2 because it should never be inlined (cost=never): noinline function attribute (hotness: 1)
+
+define void @callee1() !prof !20 {
+; CHECK: callee1 :hot
+entry:
+  ret void
+}
+
+; Function Attrs: noinline
+define void @callee2() noinline !prof !21 {
+; CHECK: callee2 :cold
+entry:
+  ret void
+}
+
+define void @caller1() !prof !20 {
+; CHECK: caller1 :hot
+entry:
+  call void @callee1()
+  ret void
+}
+
+define void @caller2() !prof !21 {
+; CHECK: caller2 :cold
+entry:
+  call void @callee2()
+  ret void
+}
+
+!llvm.module.flags = !{!1}
+!20 = !{!"function_entry_count", i64 400}
+!21 = !{!"function_entry_count", i64 1}
+
+!1 = !{i32 1, !"ProfileSummary", !2}
+!2 = !{!3, !4, !5, !6, !7, !8, !9, !10}
+!3 = !{!"ProfileFormat", !"InstrProf"}
+!4 = !{!"TotalCount", i64 10000}
+!5 = !{!"MaxCount", i64 10}
+!6 = !{!"MaxInternalCount", i64 1}
+!7 = !{!"MaxFunctionCount", i64 1000}
+!8 = !{!"NumCounts", i64 3}
+!9 = !{!"NumFunctions", i64 3}
+!10 = !{!"DetailedSummary", !11}
+!11 = !{!12, !13, !14}
+!12 = !{i32 10000, i64 100, i32 1}
+!13 = !{i32 999000, i64 100, i32 1}
+!14 = !{i32 999999, i64 1, i32 2}
+

llvm/test/Transforms/SampleProfile/Inputs/remarks-hotness.prof

+_Z7callee1v:600:600
+ 1: 600
+_Z7callee2v:1:1
+ 1: 1
+_Z7caller1v:400:400
+ 1: 400
+_Z7caller2v:1:1
+ 1: 1

llvm/test/Transforms/SampleProfile/remarks-hotness.ll

+;; This test verifies 'auto' hotness threshold when profile file is provided.
+;;
+;; new PM
+; RUN: rm -f %t.yaml %t.hot.yaml
+; RUN: opt %s --enable-new-pm --passes='sample-profile,cgscc(inline)' \
+; RUN: --sample-profile-file=%S/Inputs/remarks-hotness.prof \
+; RUN: -S --pass-remarks-filter=inline --pass-remarks-output=%t.yaml \
+; RUN: -pass-remarks-with-hotness --disable-output
+; RUN: FileCheck %s -check-prefix=YAML-PASS < %t.yaml
+; RUN: FileCheck %s -check-prefix=YAML-MISS < %t.yaml
+
+;; test 'auto' threshold
+; RUN: opt %s --enable-new-pm --passes='sample-profile,cgscc(inline)' \
+; RUN: --sample-profile-file=%S/Inputs/remarks-hotness.prof \
+; RUN: -S --pass-remarks-filter=inline --pass-remarks-output=%t.hot.yaml \
+; RUN: --pass-remarks-with-hotness --pass-remarks-hotness-threshold=auto --disable-output
+; RUN: FileCheck %s -check-prefix=YAML-PASS < %t.hot.yaml
+; RUN: not FileCheck %s -check-prefix=YAML-MISS < %t.hot.yaml
+
+; RUN: opt %s --enable-new-pm --passes='sample-profile,cgscc(inline)' \
+; RUN: --sample-profile-file=%S/Inputs/remarks-hotness.prof \
+; RUN: -S --pass-remarks=inline --pass-remarks-missed=inline --pass-remarks-analysis=inline \
+; RUN: --pass-remarks-with-hotness --pass-remarks-hotness-threshold=auto --disable-output 2>&1 | FileCheck %s -check-prefix=CHECK-RPASS
+
+; YAML-PASS:      --- !Passed
+; YAML-PASS-NEXT: Pass:            inline
+; YAML-PASS-NEXT: Name:            Inlined
+; YAML-PASS-NEXT: DebugLoc:        { File: remarks-hotness.cpp, Line: 10, Column: 10 }
+; YAML-PASS-NEXT: Function:        _Z7caller1v
+; YAML-PASS-NEXT: Hotness:         401
+
+; YAML-MISS:      --- !Missed
+; YAML-MISS-NEXT: Pass:            inline
+; YAML-MISS-NEXT: Name:            NeverInline
+; YAML-MISS-NEXT: DebugLoc:        { File: remarks-hotness.cpp, Line: 14, Column: 10 }
+; YAML-MISS-NEXT: Function:        _Z7caller2v
+; YAML-MISS-NEXT: Hotness:         2
+
+; CHECK-RPASS: _Z7callee1v inlined into _Z7caller1v with (cost=-30, threshold=4500) at callsite _Z7caller1v:1 (hotness: 401)
+; CHECK-RPASS-NOT: _Z7callee2v not inlined into _Z7caller2v because it should never be inlined (cost=never): noinline function attribute (hotness: 2)
+
+; ModuleID = 'remarks-hotness.cpp'
+source_filename = "remarks-hotness.cpp"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: use-sample-profile
+define dso_local i32 @_Z7callee1v() #0 !dbg !7 {
+  ret i32 1, !dbg !11
+}
+
+; Function Attrs: noinline nounwind uwtable use-sample-profile
+define dso_local i32 @_Z7callee2v() #1 !dbg !12 {
+  ret i32 2, !dbg !13
+}
+
+; Function Attrs: use-sample-profile
+define dso_local i32 @_Z7caller1v() #0 !dbg !14 {
+  %1 = call i32 @_Z7callee1v(), !dbg !15
+  ret i32 %1, !dbg !16
+}
+
+; Function Attrs: use-sample-profile
+define dso_local i32 @_Z7caller2v() #0 !dbg !17 {
+  %1 = call i32 @_Z7callee2v(), !dbg !18
+  ret i32 %1, !dbg !19
+}
+
+attributes #0 = { "use-sample-profile" }
+attributes #1 = { noinline nounwind uwtable "use-sample-profile" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, debugInfoForProfiling: true, nameTableKind: None)
+!1 = !DIFile(filename: "remarks-hotness.cpp", directory: ".")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 11.0.0"}
+!7 = distinct !DISubprogram(name: "callee1", linkageName: "_Z7callee1v", scope: !1, file: !1, line: 1, type: !8, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DILocation(line: 2, column: 3, scope: !7)
+!12 = distinct !DISubprogram(name: "callee2", linkageName: "_Z7callee2v", scope: !1, file: !1, line: 5, type: !8, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!13 = !DILocation(line: 6, column: 3, scope: !12)
+!14 = distinct !DISubprogram(name: "caller1", linkageName: "_Z7caller1v", scope: !1, file: !1, line: 9, type: !8, scopeLine: 9, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!15 = !DILocation(line: 10, column: 10, scope: !14)
+!16 = !DILocation(line: 10, column: 3, scope: !14)
+!17 = distinct !DISubprogram(name: "caller2", linkageName: "_Z7caller2v", scope: !1, file: !1, line: 13, type: !8, scopeLine: 13, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!18 = !DILocation(line: 14, column: 10, scope: !17)
+!19 = !DILocation(line: 14, column: 3, scope: !17)
+

llvm/tools/llc/llc.cpp

 #include "llvm/IR/LLVMRemarkStreamer.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/IRReader/IRReader.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/MC/SubtargetFeature.h"
 #include "llvm/Pass.h"
+#include "llvm/Remarks/HotnessThresholdParser.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/PluginLoader.h"

 
 static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
 
 static cl::opt<bool> RemarksWithHotness(
     "pass-remarks-with-hotness",
     cl::desc("With PGO, include profile count in optimization remarks"),
     cl::Hidden);
 
-static cl::opt<unsigned>
-    RemarksHotnessThreshold("pass-remarks-hotness-threshold",
-                            cl::desc("Minimum profile count required for "
-                                     "an optimization remark to be output"),
-                            cl::Hidden);
+static cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser>
+    RemarksHotnessThreshold(
+        "pass-remarks-hotness-threshold",
+                 "an optimization remark to be output. "
+                 "Use 'auto' to apply the threshold from profile summary."),
+        cl::value_desc("N or 'auto'"), cl::init(0), cl::Hidden);
 
 static cl::opt<std::string>
     RemarksFilename("pass-remarks-output",
                     cl::desc("Output filename for pass remarks"),
                     cl::value_desc("filename"));
 
 static cl::opt<std::string>
     RemarksPasses("pass-remarks-filter",

llvm/tools/opt/opt.cpp

 #include "llvm/IR/LegacyPassNameParser.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/IRReader/IRReader.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/LinkAllIR.h"
 #include "llvm/LinkAllPasses.h"
 #include "llvm/MC/SubtargetFeature.h"
+#include "llvm/Remarks/HotnessThresholdParser.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/SystemUtils.h"
 #include "llvm/Support/TargetRegistry.h"
TimeTraceFile("time-trace-file",
                     cl::desc("Specify time trace file destination"),
                     cl::value_desc("filename"));
 
 static cl::opt<bool> RemarksWithHotness(
     "pass-remarks-with-hotness",
     cl::desc("With PGO, include profile count in optimization remarks"),
     cl::Hidden);
 
-static cl::opt<unsigned>
-    RemarksHotnessThreshold("pass-remarks-hotness-threshold",
-                            cl::desc("Minimum profile count required for "
-                                     "an optimization remark to be output"),
-                            cl::Hidden);
+static cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser>
+    RemarksHotnessThreshold(
+        "pass-remarks-hotness-threshold",
+                 "an optimization remark to be output. "
+                 "Use 'auto' to apply the threshold from profile summary."),
+        cl::value_desc("N or 'auto'"), cl::init(0), cl::Hidden);
 
 static cl::opt<std::string>
     RemarksFilename("pass-remarks-output",
                     cl::desc("Output filename for pass remarks"),
                     cl::value_desc("filename"));
 
 static cl::opt<std::string>
     RemarksPasses("pass-remarks-filter",