[PGO] Remove legacy PM passes

Legacy PM for optimization pipeline was deprecated in 13.0.0 and Clang dropped
legacy PM support in D123609. This change removes legacy PM passes for PGO so
that downstream projects won't be able to use it. It seems appropriate to start
removing such "add-on" features like instrumentations, before we remove more
stuff after 15.x is branched.

I have checked many LLVM users and only ldc[1] uses the legacy PGO pass.

[1]: ldc-developers/ldc#3961

Reviewed By: davidxl

Differential Revision: https://reviews.llvm.org/D123834

Author: MaskRay

llvm/include/llvm/InitializePasses.h

@@ -342,11 +342,6 @@ void initializeOptimizationRemarkEmitterWrapperPassPass(PassRegistry&);
 void initializeOptimizePHIsPass(PassRegistry&);
 void initializePAEvalPass(PassRegistry&);
 void initializePEIPass(PassRegistry&);
-void initializePGOIndirectCallPromotionLegacyPassPass(PassRegistry&);
-void initializePGOInstrumentationGenLegacyPassPass(PassRegistry&);
-void initializePGOInstrumentationUseLegacyPassPass(PassRegistry&);
-void initializePGOInstrumentationGenCreateVarLegacyPassPass(PassRegistry&);
-void initializePGOMemOPSizeOptLegacyPassPass(PassRegistry&);
 void initializePHIEliminationPass(PassRegistry&);
 void initializePartialInlinerLegacyPassPass(PassRegistry&);
 void initializePartiallyInlineLibCallsLegacyPassPass(PassRegistry&);

llvm/include/llvm/LinkAllPasses.h

@@ -103,11 +103,6 @@ namespace {
       (void) llvm::createDomOnlyViewerPass();
       (void) llvm::createDomViewerPass();
       (void) llvm::createGCOVProfilerPass();
-      (void) llvm::createPGOInstrumentationGenLegacyPass();
-      (void) llvm::createPGOInstrumentationUseLegacyPass();
-      (void) llvm::createPGOInstrumentationGenCreateVarLegacyPass();
-      (void) llvm::createPGOIndirectCallPromotionLegacyPass();
-      (void) llvm::createPGOMemOPSizeOptLegacyPass();
       (void) llvm::createInstrProfilingLegacyPass();
       (void) llvm::createFunctionImportPass();
       (void) llvm::createFunctionInliningPass();

llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h

@@ -213,7 +213,6 @@ class PassManagerBuilder {
   void addInitialAliasAnalysisPasses(legacy::PassManagerBase &PM) const;
   void addLTOOptimizationPasses(legacy::PassManagerBase &PM);
   void addLateLTOOptimizationPasses(legacy::PassManagerBase &PM);
-  void addPGOInstrPasses(legacy::PassManagerBase &MPM, bool IsCS);
   void addFunctionSimplificationPasses(legacy::PassManagerBase &MPM);
   void addVectorPasses(legacy::PassManagerBase &PM, bool IsFullLTO);
 

llvm/include/llvm/Transforms/Instrumentation.h

@@ -78,18 +78,6 @@ struct GCOVOptions {
 ModulePass *createGCOVProfilerPass(const GCOVOptions &Options =
                                    GCOVOptions::getDefault());
 
-// PGO Instrumention. Parameter IsCS indicates if this is the context sensitive
-// instrumentation.
-ModulePass *createPGOInstrumentationGenLegacyPass(bool IsCS = false);
-ModulePass *
-createPGOInstrumentationUseLegacyPass(StringRef Filename = StringRef(""),
-                                      bool IsCS = false);
-ModulePass *createPGOInstrumentationGenCreateVarLegacyPass(
-    StringRef CSInstrName = StringRef(""));
-ModulePass *createPGOIndirectCallPromotionLegacyPass(bool InLTO = false,
-                                                     bool SamplePGO = false);
-FunctionPass *createPGOMemOPSizeOptLegacyPass();
-
 ModulePass *createCGProfileLegacyPass();
 
 // The pgo-specific indirect call promotion function declared below is used by

llvm/lib/Transforms/IPO/PassManagerBuilder.cpp

@@ -327,61 +327,6 @@ void PassManagerBuilder::populateFunctionPassManager(
   FPM.add(createEarlyCSEPass());
 }
 
-// Do PGO instrumentation generation or use pass as the option specified.
-void PassManagerBuilder::addPGOInstrPasses(legacy::PassManagerBase &MPM,
-                                           bool IsCS = false) {
-  if (IsCS) {
-    if (!EnablePGOCSInstrGen && !EnablePGOCSInstrUse)
-      return;
-  } else if (!EnablePGOInstrGen && PGOInstrUse.empty() && PGOSampleUse.empty())
-    return;
-
-  // Perform the preinline and cleanup passes for O1 and above.
-  // We will not do this inline for context sensitive PGO (when IsCS is true).
-  if (OptLevel > 0 && !DisablePreInliner && PGOSampleUse.empty() && !IsCS) {
-    // Create preinline pass. We construct an InlineParams object and specify
-    // the threshold here to avoid the command line options of the regular
-    // inliner to influence pre-inlining. The only fields of InlineParams we
-    // care about are DefaultThreshold and HintThreshold.
-    InlineParams IP;
-    IP.DefaultThreshold = PreInlineThreshold;
-    // FIXME: The hint threshold has the same value used by the regular inliner
-    // when not optimzing for size. This should probably be lowered after
-    // performance testing.
-    // Use PreInlineThreshold for both -Os and -Oz. Not running preinliner makes
-    // the instrumented binary unusably large. Even if PreInlineThreshold is not
-    // correct thresold for -Oz, it is better than not running preinliner.
-    IP.HintThreshold = SizeLevel > 0 ? PreInlineThreshold : 325;
-
-    MPM.add(createFunctionInliningPass(IP));
-    MPM.add(createSROAPass());
-    MPM.add(createEarlyCSEPass());             // Catch trivial redundancies
-    MPM.add(createCFGSimplificationPass(
-        SimplifyCFGOptions().convertSwitchRangeToICmp(
-            true)));                           // Merge & remove BBs
-    MPM.add(createInstructionCombiningPass()); // Combine silly seq's
-    addExtensionsToPM(EP_Peephole, MPM);
-  }
-  if ((EnablePGOInstrGen && !IsCS) || (EnablePGOCSInstrGen && IsCS)) {
-    MPM.add(createPGOInstrumentationGenLegacyPass(IsCS));
-    // Add the profile lowering pass.
-    InstrProfOptions Options;
-    if (!PGOInstrGen.empty())
-      Options.InstrProfileOutput = PGOInstrGen;
-    Options.DoCounterPromotion = true;
-    Options.UseBFIInPromotion = IsCS;
-    MPM.add(createLoopRotatePass());
-    MPM.add(createInstrProfilingLegacyPass(Options, IsCS));
-  }
-  if (!PGOInstrUse.empty())
-    MPM.add(createPGOInstrumentationUseLegacyPass(PGOInstrUse, IsCS));
-  // Indirect call promotion that promotes intra-module targets only.
-  // For ThinLTO this is done earlier due to interactions with globalopt
-  // for imported functions. We don't run this at -O0.
-  if (OptLevel > 0 && !IsCS)
-    MPM.add(
-        createPGOIndirectCallPromotionLegacyPass(false, !PGOSampleUse.empty()));
-}
 void PassManagerBuilder::addFunctionSimplificationPasses(
     legacy::PassManagerBase &MPM) {
   // Start of function pass.
@@ -423,10 +368,6 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
     MPM.add(createLibCallsShrinkWrapPass());
   addExtensionsToPM(EP_Peephole, MPM);
 
-  // Optimize memory intrinsic calls based on the profiled size information.
-  if (SizeLevel == 0)
-    MPM.add(createPGOMemOPSizeOptLegacyPass());
-
   // TODO: Investigate the cost/benefit of tail call elimination on debugging.
   if (OptLevel > 1)
     MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
@@ -666,10 +607,6 @@ void PassManagerBuilder::addVectorPasses(legacy::PassManagerBase &PM,
 
 void PassManagerBuilder::populateModulePassManager(
     legacy::PassManagerBase &MPM) {
-  // Whether this is a default or *LTO pre-link pipeline. The FullLTO post-link
-  // is handled separately, so just check this is not the ThinLTO post-link.
-  bool DefaultOrPreLinkPipeline = !PerformThinLTO;
-
   MPM.add(createAnnotation2MetadataLegacyPass());
 
   if (!PGOSampleUse.empty()) {
@@ -687,7 +624,6 @@ void PassManagerBuilder::populateModulePassManager(
   // If all optimizations are disabled, just run the always-inline pass and,
   // if enabled, the function merging pass.
   if (OptLevel == 0) {
-    addPGOInstrPasses(MPM);
     if (Inliner) {
       MPM.add(Inliner);
       Inliner = nullptr;
@@ -741,8 +677,6 @@ void PassManagerBuilder::populateModulePassManager(
   // earlier in the pass pipeline, here before globalopt. Otherwise imported
   // available_externally functions look unreferenced and are removed.
   if (PerformThinLTO) {
-    MPM.add(createPGOIndirectCallPromotionLegacyPass(/*InLTO = */ true,
-                                                     !PGOSampleUse.empty()));
     MPM.add(createLowerTypeTestsPass(nullptr, nullptr, true));
   }
 
@@ -785,19 +719,6 @@ void PassManagerBuilder::populateModulePassManager(
       createCFGSimplificationPass(SimplifyCFGOptions().convertSwitchRangeToICmp(
           true))); // Clean up after IPCP & DAE
 
-  // For SamplePGO in ThinLTO compile phase, we do not want to do indirect
-  // call promotion as it will change the CFG too much to make the 2nd
-  // profile annotation in backend more difficult.
-  // PGO instrumentation is added during the compile phase for ThinLTO, do
-  // not run it a second time
-  if (DefaultOrPreLinkPipeline && !PrepareForThinLTOUsingPGOSampleProfile)
-    addPGOInstrPasses(MPM);
-
-  // Create profile COMDAT variables. Lld linker wants to see all variables
-  // before the LTO/ThinLTO link since it needs to resolve symbols/comdats.
-  if (!PerformThinLTO && EnablePGOCSInstrGen)
-    MPM.add(createPGOInstrumentationGenCreateVarLegacyPass(PGOInstrGen));
-
   // We add a module alias analysis pass here. In part due to bugs in the
   // analysis infrastructure this "works" in that the analysis stays alive
   // for the entire SCC pass run below.
@@ -848,14 +769,6 @@ void PassManagerBuilder::populateModulePassManager(
     // and saves running remaining passes on the eliminated functions.
     MPM.add(createEliminateAvailableExternallyPass());
 
-  // CSFDO instrumentation and use pass. Don't invoke this for Prepare pass
-  // for LTO and ThinLTO -- The actual pass will be called after all inlines
-  // are performed.
-  // Need to do this after COMDAT variables have been eliminated,
-  // (i.e. after EliminateAvailableExternallyPass).
-  if (!(PrepareForLTO || PrepareForThinLTO))
-    addPGOInstrPasses(MPM, /* IsCS */ true);
-
   if (EnableOrderFileInstrumentation)
     MPM.add(createInstrOrderFilePass());
 
@@ -1022,13 +935,6 @@ void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
     // Split call-site with more constrained arguments.
     PM.add(createCallSiteSplittingPass());
 
-    // Indirect call promotion. This should promote all the targets that are
-    // left by the earlier promotion pass that promotes intra-module targets.
-    // This two-step promotion is to save the compile time. For LTO, it should
-    // produce the same result as if we only do promotion here.
-    PM.add(
-        createPGOIndirectCallPromotionLegacyPass(true, !PGOSampleUse.empty()));
-
     // Propage constant function arguments by specializing the functions.
     if (EnableFunctionSpecialization && OptLevel > 2)
       PM.add(createFunctionSpecializationPass());
@@ -1094,9 +1000,6 @@ void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
 
   PM.add(createPruneEHPass());   // Remove dead EH info.
 
-  // CSFDO instrumentation and use pass.
-  addPGOInstrPasses(PM, /* IsCS */ true);
-
   // Infer attributes on declarations, call sites, arguments, etc. for an SCC.
   if (AttributorRun & AttributorRunOption::CGSCC)
     PM.add(createAttributorCGSCCLegacyPass());

llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp

@@ -106,55 +106,6 @@ static cl::opt<bool>
 
 namespace {
 
-class PGOIndirectCallPromotionLegacyPass : public ModulePass {
-public:
-  static char ID;
-
-  PGOIndirectCallPromotionLegacyPass(bool InLTO = false, bool SamplePGO = false)
-      : ModulePass(ID), InLTO(InLTO), SamplePGO(SamplePGO) {
-    initializePGOIndirectCallPromotionLegacyPassPass(
-        *PassRegistry::getPassRegistry());
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<ProfileSummaryInfoWrapperPass>();
-  }
-
-  StringRef getPassName() const override { return "PGOIndirectCallPromotion"; }
-
-private:
-  bool runOnModule(Module &M) override;
-
-  // If this pass is called in LTO. We need to special handling the PGOFuncName
-  // for the static variables due to LTO's internalization.
-  bool InLTO;
-
-  // If this pass is called in SamplePGO. We need to add the prof metadata to
-  // the promoted direct call.
-  bool SamplePGO;
-};
-
-} // end anonymous namespace
-
-char PGOIndirectCallPromotionLegacyPass::ID = 0;
-
-INITIALIZE_PASS_BEGIN(PGOIndirectCallPromotionLegacyPass, "pgo-icall-prom",
-                      "Use PGO instrumentation profile to promote indirect "
-                      "calls to direct calls.",
-                      false, false)
-INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
-INITIALIZE_PASS_END(PGOIndirectCallPromotionLegacyPass, "pgo-icall-prom",
-                    "Use PGO instrumentation profile to promote indirect "
-                    "calls to direct calls.",
-                    false, false)
-
-ModulePass *llvm::createPGOIndirectCallPromotionLegacyPass(bool InLTO,
-                                                           bool SamplePGO) {
-  return new PGOIndirectCallPromotionLegacyPass(InLTO, SamplePGO);
-}
-
-namespace {
-
 // The class for main data structure to promote indirect calls to conditional
 // direct calls.
 class ICallPromotionFunc {
@@ -419,15 +370,6 @@ static bool promoteIndirectCalls(Module &M, ProfileSummaryInfo *PSI,
   return Changed;
 }
 
-bool PGOIndirectCallPromotionLegacyPass::runOnModule(Module &M) {
-  ProfileSummaryInfo *PSI =
-      &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
-
-  // Command-line option has the priority for InLTO.
-  return promoteIndirectCalls(M, PSI, InLTO | ICPLTOMode,
-                              SamplePGO | ICPSamplePGOMode);
-}
-
 PreservedAnalyses PGOIndirectCallPromotion::run(Module &M,
                                                 ModuleAnalysisManager &AM) {
   ProfileSummaryInfo *PSI = &AM.getResult<ProfileSummaryAnalysis>(M);

llvm/lib/Transforms/Instrumentation/Instrumentation.cpp

@@ -98,10 +98,6 @@ void llvm::initializeInstrumentation(PassRegistry &Registry) {
   initializeBoundsCheckingLegacyPassPass(Registry);
   initializeControlHeightReductionLegacyPassPass(Registry);
   initializeGCOVProfilerLegacyPassPass(Registry);
-  initializePGOInstrumentationGenLegacyPassPass(Registry);
-  initializePGOInstrumentationUseLegacyPassPass(Registry);
-  initializePGOIndirectCallPromotionLegacyPassPass(Registry);
-  initializePGOMemOPSizeOptLegacyPassPass(Registry);
   initializeCGProfileLegacyPassPass(Registry);
   initializeInstrOrderFileLegacyPassPass(Registry);
   initializeInstrProfilingLegacyPassPass(Registry);