| //===- PassManagerBuilder.cpp - Build Standard Pass -----------------------===// | 
 | // | 
 | // 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 | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 | // | 
 | // This file defines the PassManagerBuilder class, which is used to set up a | 
 | // "standard" optimization sequence suitable for languages like C and C++. | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 |  | 
 | #include "llvm/Transforms/IPO/PassManagerBuilder.h" | 
 | #include "llvm-c/Transforms/PassManagerBuilder.h" | 
 | #include "llvm/ADT/STLExtras.h" | 
 | #include "llvm/ADT/SmallVector.h" | 
 | #include "llvm/Analysis/BasicAliasAnalysis.h" | 
 | #include "llvm/Analysis/CFLAndersAliasAnalysis.h" | 
 | #include "llvm/Analysis/CFLSteensAliasAnalysis.h" | 
 | #include "llvm/Analysis/GlobalsModRef.h" | 
 | #include "llvm/Analysis/InlineCost.h" | 
 | #include "llvm/Analysis/Passes.h" | 
 | #include "llvm/Analysis/ScopedNoAliasAA.h" | 
 | #include "llvm/Analysis/TargetLibraryInfo.h" | 
 | #include "llvm/Analysis/TypeBasedAliasAnalysis.h" | 
 | #include "llvm/IR/DataLayout.h" | 
 | #include "llvm/IR/LegacyPassManager.h" | 
 | #include "llvm/IR/Verifier.h" | 
 | #include "llvm/Support/CommandLine.h" | 
 | #include "llvm/Support/ManagedStatic.h" | 
 | #include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h" | 
 | #include "llvm/Transforms/IPO.h" | 
 | #include "llvm/Transforms/IPO/Attributor.h" | 
 | #include "llvm/Transforms/IPO/ForceFunctionAttrs.h" | 
 | #include "llvm/Transforms/IPO/FunctionAttrs.h" | 
 | #include "llvm/Transforms/IPO/InferFunctionAttrs.h" | 
 | #include "llvm/Transforms/InstCombine/InstCombine.h" | 
 | #include "llvm/Transforms/Instrumentation.h" | 
 | #include "llvm/Transforms/Scalar.h" | 
 | #include "llvm/Transforms/Scalar/GVN.h" | 
 | #include "llvm/Transforms/Scalar/InstSimplifyPass.h" | 
 | #include "llvm/Transforms/Scalar/LICM.h" | 
 | #include "llvm/Transforms/Scalar/LoopUnrollPass.h" | 
 | #include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h" | 
 | #include "llvm/Transforms/Utils.h" | 
 | #include "llvm/Transforms/Vectorize.h" | 
 | #include "llvm/Transforms/Vectorize/LoopVectorize.h" | 
 | #include "llvm/Transforms/Vectorize/SLPVectorizer.h" | 
 |  | 
 | using namespace llvm; | 
 |  | 
 | static cl::opt<bool> | 
 |     RunPartialInlining("enable-partial-inlining", cl::init(false), cl::Hidden, | 
 |                        cl::ZeroOrMore, cl::desc("Run Partial inlinining pass")); | 
 |  | 
 | static cl::opt<bool> | 
 | UseGVNAfterVectorization("use-gvn-after-vectorization", | 
 |   cl::init(false), cl::Hidden, | 
 |   cl::desc("Run GVN instead of Early CSE after vectorization passes")); | 
 |  | 
 | static cl::opt<bool> ExtraVectorizerPasses( | 
 |     "extra-vectorizer-passes", cl::init(false), cl::Hidden, | 
 |     cl::desc("Run cleanup optimization passes after vectorization.")); | 
 |  | 
 | static cl::opt<bool> | 
 | RunLoopRerolling("reroll-loops", cl::Hidden, | 
 |                  cl::desc("Run the loop rerolling pass")); | 
 |  | 
 | static cl::opt<bool> RunNewGVN("enable-newgvn", cl::init(false), cl::Hidden, | 
 |                                cl::desc("Run the NewGVN pass")); | 
 |  | 
 | // Experimental option to use CFL-AA | 
 | enum class CFLAAType { None, Steensgaard, Andersen, Both }; | 
 | static cl::opt<CFLAAType> | 
 |     UseCFLAA("use-cfl-aa", cl::init(CFLAAType::None), cl::Hidden, | 
 |              cl::desc("Enable the new, experimental CFL alias analysis"), | 
 |              cl::values(clEnumValN(CFLAAType::None, "none", "Disable CFL-AA"), | 
 |                         clEnumValN(CFLAAType::Steensgaard, "steens", | 
 |                                    "Enable unification-based CFL-AA"), | 
 |                         clEnumValN(CFLAAType::Andersen, "anders", | 
 |                                    "Enable inclusion-based CFL-AA"), | 
 |                         clEnumValN(CFLAAType::Both, "both", | 
 |                                    "Enable both variants of CFL-AA"))); | 
 |  | 
 | static cl::opt<bool> EnableLoopInterchange( | 
 |     "enable-loopinterchange", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable the new, experimental LoopInterchange Pass")); | 
 |  | 
 | static cl::opt<bool> EnableUnrollAndJam("enable-unroll-and-jam", | 
 |                                         cl::init(false), cl::Hidden, | 
 |                                         cl::desc("Enable Unroll And Jam Pass")); | 
 |  | 
 | static cl::opt<bool> | 
 |     EnablePrepareForThinLTO("prepare-for-thinlto", cl::init(false), cl::Hidden, | 
 |                             cl::desc("Enable preparation for ThinLTO.")); | 
 |  | 
 | static cl::opt<bool> | 
 |     EnablePerformThinLTO("perform-thinlto", cl::init(false), cl::Hidden, | 
 |                          cl::desc("Enable performing ThinLTO.")); | 
 |  | 
 | cl::opt<bool> EnableHotColdSplit("hot-cold-split", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable hot-cold splitting pass")); | 
 |  | 
 | static cl::opt<bool> UseLoopVersioningLICM( | 
 |     "enable-loop-versioning-licm", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable the experimental Loop Versioning LICM pass")); | 
 |  | 
 | static cl::opt<bool> | 
 |     DisablePreInliner("disable-preinline", cl::init(false), cl::Hidden, | 
 |                       cl::desc("Disable pre-instrumentation inliner")); | 
 |  | 
 | static cl::opt<int> PreInlineThreshold( | 
 |     "preinline-threshold", cl::Hidden, cl::init(75), cl::ZeroOrMore, | 
 |     cl::desc("Control the amount of inlining in pre-instrumentation inliner " | 
 |              "(default = 75)")); | 
 |  | 
 | static cl::opt<bool> EnableGVNHoist( | 
 |     "enable-gvn-hoist", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable the GVN hoisting pass (default = off)")); | 
 |  | 
 | static cl::opt<bool> | 
 |     DisableLibCallsShrinkWrap("disable-libcalls-shrinkwrap", cl::init(false), | 
 |                               cl::Hidden, | 
 |                               cl::desc("Disable shrink-wrap library calls")); | 
 |  | 
 | static cl::opt<bool> EnableSimpleLoopUnswitch( | 
 |     "enable-simple-loop-unswitch", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable the simple loop unswitch pass. Also enables independent " | 
 |              "cleanup passes integrated into the loop pass manager pipeline.")); | 
 |  | 
 | static cl::opt<bool> EnableGVNSink( | 
 |     "enable-gvn-sink", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable the GVN sinking pass (default = off)")); | 
 |  | 
 | // This option is used in simplifying testing SampleFDO optimizations for | 
 | // profile loading. | 
 | static cl::opt<bool> | 
 |     EnableCHR("enable-chr", cl::init(true), cl::Hidden, | 
 |               cl::desc("Enable control height reduction optimization (CHR)")); | 
 |  | 
 | cl::opt<bool> FlattenedProfileUsed( | 
 |     "flattened-profile-used", cl::init(false), cl::Hidden, | 
 |     cl::desc("Indicate the sample profile being used is flattened, i.e., " | 
 |              "no inline hierachy exists in the profile. ")); | 
 |  | 
 | cl::opt<bool> EnableOrderFileInstrumentation( | 
 |     "enable-order-file-instrumentation", cl::init(false), cl::Hidden, | 
 |     cl::desc("Enable order file instrumentation (default = off)")); | 
 |  | 
 | static cl::opt<bool> | 
 |     EnableMatrix("enable-matrix", cl::init(false), cl::Hidden, | 
 |                  cl::desc("Enable lowering of the matrix intrinsics")); | 
 |  | 
 | PassManagerBuilder::PassManagerBuilder() { | 
 |     OptLevel = 2; | 
 |     SizeLevel = 0; | 
 |     LibraryInfo = nullptr; | 
 |     Inliner = nullptr; | 
 |     DisableUnrollLoops = false; | 
 |     SLPVectorize = RunSLPVectorization; | 
 |     LoopVectorize = EnableLoopVectorization; | 
 |     LoopsInterleaved = EnableLoopInterleaving; | 
 |     RerollLoops = RunLoopRerolling; | 
 |     NewGVN = RunNewGVN; | 
 |     LicmMssaOptCap = SetLicmMssaOptCap; | 
 |     LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap; | 
 |     DisableGVNLoadPRE = false; | 
 |     ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll; | 
 |     VerifyInput = false; | 
 |     VerifyOutput = false; | 
 |     MergeFunctions = false; | 
 |     PrepareForLTO = false; | 
 |     EnablePGOInstrGen = false; | 
 |     EnablePGOCSInstrGen = false; | 
 |     EnablePGOCSInstrUse = false; | 
 |     PGOInstrGen = ""; | 
 |     PGOInstrUse = ""; | 
 |     PGOSampleUse = ""; | 
 |     PrepareForThinLTO = EnablePrepareForThinLTO; | 
 |     PerformThinLTO = EnablePerformThinLTO; | 
 |     DivergentTarget = false; | 
 | } | 
 |  | 
 | PassManagerBuilder::~PassManagerBuilder() { | 
 |   delete LibraryInfo; | 
 |   delete Inliner; | 
 | } | 
 |  | 
 | /// Set of global extensions, automatically added as part of the standard set. | 
 | static ManagedStatic< | 
 |     SmallVector<std::tuple<PassManagerBuilder::ExtensionPointTy, | 
 |                            PassManagerBuilder::ExtensionFn, | 
 |                            PassManagerBuilder::GlobalExtensionID>, | 
 |                 8>> | 
 |     GlobalExtensions; | 
 | static PassManagerBuilder::GlobalExtensionID GlobalExtensionsCounter; | 
 |  | 
 | /// Check if GlobalExtensions is constructed and not empty. | 
 | /// Since GlobalExtensions is a managed static, calling 'empty()' will trigger | 
 | /// the construction of the object. | 
 | static bool GlobalExtensionsNotEmpty() { | 
 |   return GlobalExtensions.isConstructed() && !GlobalExtensions->empty(); | 
 | } | 
 |  | 
 | PassManagerBuilder::GlobalExtensionID | 
 | PassManagerBuilder::addGlobalExtension(PassManagerBuilder::ExtensionPointTy Ty, | 
 |                                        PassManagerBuilder::ExtensionFn Fn) { | 
 |   auto ExtensionID = GlobalExtensionsCounter++; | 
 |   GlobalExtensions->push_back(std::make_tuple(Ty, std::move(Fn), ExtensionID)); | 
 |   return ExtensionID; | 
 | } | 
 |  | 
 | void PassManagerBuilder::removeGlobalExtension( | 
 |     PassManagerBuilder::GlobalExtensionID ExtensionID) { | 
 |   // RegisterStandardPasses may try to call this function after GlobalExtensions | 
 |   // has already been destroyed; doing so should not generate an error. | 
 |   if (!GlobalExtensions.isConstructed()) | 
 |     return; | 
 |  | 
 |   auto GlobalExtension = | 
 |       llvm::find_if(*GlobalExtensions, [ExtensionID](const auto &elem) { | 
 |         return std::get<2>(elem) == ExtensionID; | 
 |       }); | 
 |   assert(GlobalExtension != GlobalExtensions->end() && | 
 |          "The extension ID to be removed should always be valid."); | 
 |  | 
 |   GlobalExtensions->erase(GlobalExtension); | 
 | } | 
 |  | 
 | void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) { | 
 |   Extensions.push_back(std::make_pair(Ty, std::move(Fn))); | 
 | } | 
 |  | 
 | void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy, | 
 |                                            legacy::PassManagerBase &PM) const { | 
 |   if (GlobalExtensionsNotEmpty()) { | 
 |     for (auto &Ext : *GlobalExtensions) { | 
 |       if (std::get<0>(Ext) == ETy) | 
 |         std::get<1>(Ext)(*this, PM); | 
 |     } | 
 |   } | 
 |   for (unsigned i = 0, e = Extensions.size(); i != e; ++i) | 
 |     if (Extensions[i].first == ETy) | 
 |       Extensions[i].second(*this, PM); | 
 | } | 
 |  | 
 | void PassManagerBuilder::addInitialAliasAnalysisPasses( | 
 |     legacy::PassManagerBase &PM) const { | 
 |   switch (UseCFLAA) { | 
 |   case CFLAAType::Steensgaard: | 
 |     PM.add(createCFLSteensAAWrapperPass()); | 
 |     break; | 
 |   case CFLAAType::Andersen: | 
 |     PM.add(createCFLAndersAAWrapperPass()); | 
 |     break; | 
 |   case CFLAAType::Both: | 
 |     PM.add(createCFLSteensAAWrapperPass()); | 
 |     PM.add(createCFLAndersAAWrapperPass()); | 
 |     break; | 
 |   default: | 
 |     break; | 
 |   } | 
 |  | 
 |   // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that | 
 |   // BasicAliasAnalysis wins if they disagree. This is intended to help | 
 |   // support "obvious" type-punning idioms. | 
 |   PM.add(createTypeBasedAAWrapperPass()); | 
 |   PM.add(createScopedNoAliasAAWrapperPass()); | 
 | } | 
 |  | 
 | void PassManagerBuilder::addInstructionCombiningPass( | 
 |     legacy::PassManagerBase &PM) const { | 
 |   bool ExpensiveCombines = OptLevel > 2; | 
 |   PM.add(createInstructionCombiningPass(ExpensiveCombines)); | 
 | } | 
 |  | 
 | void PassManagerBuilder::populateFunctionPassManager( | 
 |     legacy::FunctionPassManager &FPM) { | 
 |   addExtensionsToPM(EP_EarlyAsPossible, FPM); | 
 |   FPM.add(createEntryExitInstrumenterPass()); | 
 |  | 
 |   // Add LibraryInfo if we have some. | 
 |   if (LibraryInfo) | 
 |     FPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); | 
 |  | 
 |   if (OptLevel == 0) return; | 
 |  | 
 |   addInitialAliasAnalysisPasses(FPM); | 
 |  | 
 |   FPM.add(createCFGSimplificationPass()); | 
 |   FPM.add(createSROAPass()); | 
 |   FPM.add(createEarlyCSEPass()); | 
 |   FPM.add(createLowerExpectIntrinsicPass()); | 
 | } | 
 |  | 
 | // 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. | 
 |   // And avoid doing them if optimizing for size. | 
 |   // We will not do this inline for context sensitive PGO (when IsCS is true). | 
 |   if (OptLevel > 0 && SizeLevel == 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. | 
 |     // This should probably be lowered after performance testing. | 
 |     IP.HintThreshold = 325; | 
 |  | 
 |     MPM.add(createFunctionInliningPass(IP)); | 
 |     MPM.add(createSROAPass()); | 
 |     MPM.add(createEarlyCSEPass());             // Catch trivial redundancies | 
 |     MPM.add(createCFGSimplificationPass());    // 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. | 
 |   // Break up aggregate allocas, using SSAUpdater. | 
 |   assert(OptLevel >= 1 && "Calling function optimizer with no optimization level!"); | 
 |   MPM.add(createSROAPass()); | 
 |   MPM.add(createEarlyCSEPass(true /* Enable mem-ssa. */)); // Catch trivial redundancies | 
 |  | 
 |   if (OptLevel > 1) { | 
 |     if (EnableGVNHoist) | 
 |       MPM.add(createGVNHoistPass()); | 
 |     if (EnableGVNSink) { | 
 |       MPM.add(createGVNSinkPass()); | 
 |       MPM.add(createCFGSimplificationPass()); | 
 |     } | 
 |   } | 
 |  | 
 |   if (OptLevel > 1) { | 
 |     // Speculative execution if the target has divergent branches; otherwise nop. | 
 |     MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass()); | 
 |  | 
 |     MPM.add(createJumpThreadingPass());         // Thread jumps. | 
 |     MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals | 
 |   } | 
 |   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs | 
 |   // Combine silly seq's | 
 |   if (OptLevel > 2) | 
 |     MPM.add(createAggressiveInstCombinerPass()); | 
 |   addInstructionCombiningPass(MPM); | 
 |   if (SizeLevel == 0 && !DisableLibCallsShrinkWrap) | 
 |     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 | 
 |   MPM.add(createCFGSimplificationPass());      // Merge & remove BBs | 
 |   MPM.add(createReassociatePass());           // Reassociate expressions | 
 |  | 
 |   // Begin the loop pass pipeline. | 
 |   if (EnableSimpleLoopUnswitch) { | 
 |     // The simple loop unswitch pass relies on separate cleanup passes. Schedule | 
 |     // them first so when we re-process a loop they run before other loop | 
 |     // passes. | 
 |     MPM.add(createLoopInstSimplifyPass()); | 
 |     MPM.add(createLoopSimplifyCFGPass()); | 
 |   } | 
 |   // Rotate Loop - disable header duplication at -Oz | 
 |   MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1)); | 
 |   // TODO: Investigate promotion cap for O1. | 
 |   MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap)); | 
 |   if (EnableSimpleLoopUnswitch) | 
 |     MPM.add(createSimpleLoopUnswitchLegacyPass()); | 
 |   else | 
 |     MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3, DivergentTarget)); | 
 |   // FIXME: We break the loop pass pipeline here in order to do full | 
 |   // simplify-cfg. Eventually loop-simplifycfg should be enhanced to replace the | 
 |   // need for this. | 
 |   MPM.add(createCFGSimplificationPass()); | 
 |   addInstructionCombiningPass(MPM); | 
 |   // We resume loop passes creating a second loop pipeline here. | 
 |   MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars | 
 |   MPM.add(createLoopIdiomPass());             // Recognize idioms like memset. | 
 |   addExtensionsToPM(EP_LateLoopOptimizations, MPM); | 
 |   MPM.add(createLoopDeletionPass());          // Delete dead loops | 
 |  | 
 |   if (EnableLoopInterchange) | 
 |     MPM.add(createLoopInterchangePass()); // Interchange loops | 
 |  | 
 |   // Unroll small loops | 
 |   MPM.add(createSimpleLoopUnrollPass(OptLevel, DisableUnrollLoops, | 
 |                                      ForgetAllSCEVInLoopUnroll)); | 
 |   addExtensionsToPM(EP_LoopOptimizerEnd, MPM); | 
 |   // This ends the loop pass pipelines. | 
 |  | 
 |   if (OptLevel > 1) { | 
 |     MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds | 
 |     MPM.add(NewGVN ? createNewGVNPass() | 
 |                    : createGVNPass(DisableGVNLoadPRE)); // Remove redundancies | 
 |   } | 
 |   MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset | 
 |   MPM.add(createSCCPPass());                  // Constant prop with SCCP | 
 |  | 
 |   // Delete dead bit computations (instcombine runs after to fold away the dead | 
 |   // computations, and then ADCE will run later to exploit any new DCE | 
 |   // opportunities that creates). | 
 |   MPM.add(createBitTrackingDCEPass());        // Delete dead bit computations | 
 |  | 
 |   // Run instcombine after redundancy elimination to exploit opportunities | 
 |   // opened up by them. | 
 |   addInstructionCombiningPass(MPM); | 
 |   addExtensionsToPM(EP_Peephole, MPM); | 
 |   if (OptLevel > 1) { | 
 |     MPM.add(createJumpThreadingPass());         // Thread jumps | 
 |     MPM.add(createCorrelatedValuePropagationPass()); | 
 |     MPM.add(createDeadStoreEliminationPass());  // Delete dead stores | 
 |     MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap)); | 
 |   } | 
 |  | 
 |   addExtensionsToPM(EP_ScalarOptimizerLate, MPM); | 
 |  | 
 |   if (RerollLoops) | 
 |     MPM.add(createLoopRerollPass()); | 
 |  | 
 |   // TODO: Investigate if this is too expensive at O1. | 
 |   MPM.add(createAggressiveDCEPass());         // Delete dead instructions | 
 |   MPM.add(createCFGSimplificationPass()); // Merge & remove BBs | 
 |   // Clean up after everything. | 
 |   addInstructionCombiningPass(MPM); | 
 |   addExtensionsToPM(EP_Peephole, MPM); | 
 |  | 
 |   if (EnableCHR && OptLevel >= 3 && | 
 |       (!PGOInstrUse.empty() || !PGOSampleUse.empty() || EnablePGOCSInstrGen)) | 
 |     MPM.add(createControlHeightReductionLegacyPass()); | 
 | } | 
 |  | 
 | 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; | 
 |  | 
 |   if (!PGOSampleUse.empty()) { | 
 |     MPM.add(createPruneEHPass()); | 
 |     // In ThinLTO mode, when flattened profile is used, all the available | 
 |     // profile information will be annotated in PreLink phase so there is | 
 |     // no need to load the profile again in PostLink. | 
 |     if (!(FlattenedProfileUsed && PerformThinLTO)) | 
 |       MPM.add(createSampleProfileLoaderPass(PGOSampleUse)); | 
 |   } | 
 |  | 
 |   // Allow forcing function attributes as a debugging and tuning aid. | 
 |   MPM.add(createForceFunctionAttrsLegacyPass()); | 
 |  | 
 |   // 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; | 
 |     } | 
 |  | 
 |     // FIXME: The BarrierNoopPass is a HACK! The inliner pass above implicitly | 
 |     // creates a CGSCC pass manager, but we don't want to add extensions into | 
 |     // that pass manager. To prevent this we insert a no-op module pass to reset | 
 |     // the pass manager to get the same behavior as EP_OptimizerLast in non-O0 | 
 |     // builds. The function merging pass is | 
 |     if (MergeFunctions) | 
 |       MPM.add(createMergeFunctionsPass()); | 
 |     else if (GlobalExtensionsNotEmpty() || !Extensions.empty()) | 
 |       MPM.add(createBarrierNoopPass()); | 
 |  | 
 |     if (PerformThinLTO) { | 
 |       // Drop available_externally and unreferenced globals. This is necessary | 
 |       // with ThinLTO in order to avoid leaving undefined references to dead | 
 |       // globals in the object file. | 
 |       MPM.add(createEliminateAvailableExternallyPass()); | 
 |       MPM.add(createGlobalDCEPass()); | 
 |     } | 
 |  | 
 |     addExtensionsToPM(EP_EnabledOnOptLevel0, MPM); | 
 |  | 
 |     if (PrepareForLTO || PrepareForThinLTO) { | 
 |       MPM.add(createCanonicalizeAliasesPass()); | 
 |       // Rename anon globals to be able to export them in the summary. | 
 |       // This has to be done after we add the extensions to the pass manager | 
 |       // as there could be passes (e.g. Adddress sanitizer) which introduce | 
 |       // new unnamed globals. | 
 |       MPM.add(createNameAnonGlobalPass()); | 
 |     } | 
 |     return; | 
 |   } | 
 |  | 
 |   // Add LibraryInfo if we have some. | 
 |   if (LibraryInfo) | 
 |     MPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); | 
 |  | 
 |   addInitialAliasAnalysisPasses(MPM); | 
 |  | 
 |   // For ThinLTO there are two passes of indirect call promotion. The | 
 |   // first is during the compile phase when PerformThinLTO=false and | 
 |   // intra-module indirect call targets are promoted. The second is during | 
 |   // the ThinLTO backend when PerformThinLTO=true, when we promote imported | 
 |   // inter-module indirect calls. For that we perform indirect call promotion | 
 |   // 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())); | 
 |  | 
 |   // For SamplePGO in ThinLTO compile phase, we do not want to unroll loops | 
 |   // as it will change the CFG too much to make the 2nd profile annotation | 
 |   // in backend more difficult. | 
 |   bool PrepareForThinLTOUsingPGOSampleProfile = | 
 |       PrepareForThinLTO && !PGOSampleUse.empty(); | 
 |   if (PrepareForThinLTOUsingPGOSampleProfile) | 
 |     DisableUnrollLoops = true; | 
 |  | 
 |   // Infer attributes about declarations if possible. | 
 |   MPM.add(createInferFunctionAttrsLegacyPass()); | 
 |  | 
 |   addExtensionsToPM(EP_ModuleOptimizerEarly, MPM); | 
 |  | 
 |   if (OptLevel > 2) | 
 |     MPM.add(createCallSiteSplittingPass()); | 
 |  | 
 |   MPM.add(createIPSCCPPass());          // IP SCCP | 
 |   MPM.add(createCalledValuePropagationPass()); | 
 |  | 
 |   // Infer attributes on declarations, call sites, arguments, etc. | 
 |   MPM.add(createAttributorLegacyPass()); | 
 |  | 
 |   MPM.add(createGlobalOptimizerPass()); // Optimize out global vars | 
 |   // Promote any localized global vars. | 
 |   MPM.add(createPromoteMemoryToRegisterPass()); | 
 |  | 
 |   MPM.add(createDeadArgEliminationPass()); // Dead argument elimination | 
 |  | 
 |   addInstructionCombiningPass(MPM); // Clean up after IPCP & DAE | 
 |   addExtensionsToPM(EP_Peephole, MPM); | 
 |   MPM.add(createCFGSimplificationPass()); // 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. | 
 |   MPM.add(createGlobalsAAWrapperPass()); | 
 |  | 
 |   // Start of CallGraph SCC passes. | 
 |   MPM.add(createPruneEHPass()); // Remove dead EH info | 
 |   bool RunInliner = false; | 
 |   if (Inliner) { | 
 |     MPM.add(Inliner); | 
 |     Inliner = nullptr; | 
 |     RunInliner = true; | 
 |   } | 
 |  | 
 |   MPM.add(createPostOrderFunctionAttrsLegacyPass()); | 
 |   if (OptLevel > 2) | 
 |     MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args | 
 |  | 
 |   addExtensionsToPM(EP_CGSCCOptimizerLate, MPM); | 
 |   addFunctionSimplificationPasses(MPM); | 
 |  | 
 |   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC | 
 |   // pass manager that we are specifically trying to avoid. To prevent this | 
 |   // we must insert a no-op module pass to reset the pass manager. | 
 |   MPM.add(createBarrierNoopPass()); | 
 |  | 
 |   if (RunPartialInlining) | 
 |     MPM.add(createPartialInliningPass()); | 
 |  | 
 |   if (OptLevel > 1 && !PrepareForLTO && !PrepareForThinLTO) | 
 |     // Remove avail extern fns and globals definitions if we aren't | 
 |     // compiling an object file for later LTO. For LTO we want to preserve | 
 |     // these so they are eligible for inlining at link-time. Note if they | 
 |     // are unreferenced they will be removed by GlobalDCE later, so | 
 |     // this only impacts referenced available externally globals. | 
 |     // Eventually they will be suppressed during codegen, but eliminating | 
 |     // here enables more opportunity for GlobalDCE as it may make | 
 |     // globals referenced by available external functions dead | 
 |     // 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()); | 
 |  | 
 |   MPM.add(createReversePostOrderFunctionAttrsPass()); | 
 |  | 
 |   // The inliner performs some kind of dead code elimination as it goes, | 
 |   // but there are cases that are not really caught by it. We might | 
 |   // at some point consider teaching the inliner about them, but it | 
 |   // is OK for now to run GlobalOpt + GlobalDCE in tandem as their | 
 |   // benefits generally outweight the cost, making the whole pipeline | 
 |   // faster. | 
 |   if (RunInliner) { | 
 |     MPM.add(createGlobalOptimizerPass()); | 
 |     MPM.add(createGlobalDCEPass()); | 
 |   } | 
 |  | 
 |   // If we are planning to perform ThinLTO later, let's not bloat the code with | 
 |   // unrolling/vectorization/... now. We'll first run the inliner + CGSCC passes | 
 |   // during ThinLTO and perform the rest of the optimizations afterward. | 
 |   if (PrepareForThinLTO) { | 
 |     // Ensure we perform any last passes, but do so before renaming anonymous | 
 |     // globals in case the passes add any. | 
 |     addExtensionsToPM(EP_OptimizerLast, MPM); | 
 |     MPM.add(createCanonicalizeAliasesPass()); | 
 |     // Rename anon globals to be able to export them in the summary. | 
 |     MPM.add(createNameAnonGlobalPass()); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (PerformThinLTO) | 
 |     // Optimize globals now when performing ThinLTO, this enables more | 
 |     // optimizations later. | 
 |     MPM.add(createGlobalOptimizerPass()); | 
 |  | 
 |   // Scheduling LoopVersioningLICM when inlining is over, because after that | 
 |   // we may see more accurate aliasing. Reason to run this late is that too | 
 |   // early versioning may prevent further inlining due to increase of code | 
 |   // size. By placing it just after inlining other optimizations which runs | 
 |   // later might get benefit of no-alias assumption in clone loop. | 
 |   if (UseLoopVersioningLICM) { | 
 |     MPM.add(createLoopVersioningLICMPass());    // Do LoopVersioningLICM | 
 |     MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap)); | 
 |   } | 
 |  | 
 |   // We add a fresh GlobalsModRef run at this point. This is particularly | 
 |   // useful as the above will have inlined, DCE'ed, and function-attr | 
 |   // propagated everything. We should at this point have a reasonably minimal | 
 |   // and richly annotated call graph. By computing aliasing and mod/ref | 
 |   // information for all local globals here, the late loop passes and notably | 
 |   // the vectorizer will be able to use them to help recognize vectorizable | 
 |   // memory operations. | 
 |   // | 
 |   // Note that this relies on a bug in the pass manager which preserves | 
 |   // a module analysis into a function pass pipeline (and throughout it) so | 
 |   // long as the first function pass doesn't invalidate the module analysis. | 
 |   // Thus both Float2Int and LoopRotate have to preserve AliasAnalysis for | 
 |   // this to work. Fortunately, it is trivial to preserve AliasAnalysis | 
 |   // (doing nothing preserves it as it is required to be conservatively | 
 |   // correct in the face of IR changes). | 
 |   MPM.add(createGlobalsAAWrapperPass()); | 
 |  | 
 |   MPM.add(createFloat2IntPass()); | 
 |   MPM.add(createLowerConstantIntrinsicsPass()); | 
 |  | 
 |   if (EnableMatrix) { | 
 |     MPM.add(createLowerMatrixIntrinsicsPass()); | 
 |     // CSE the pointer arithmetic of the column vectors.  This allows alias | 
 |     // analysis to establish no-aliasing between loads and stores of different | 
 |     // columns of the same matrix. | 
 |     MPM.add(createEarlyCSEPass(false)); | 
 |   } | 
 |  | 
 |   addExtensionsToPM(EP_VectorizerStart, MPM); | 
 |  | 
 |   // Re-rotate loops in all our loop nests. These may have fallout out of | 
 |   // rotated form due to GVN or other transformations, and the vectorizer relies | 
 |   // on the rotated form. Disable header duplication at -Oz. | 
 |   MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1)); | 
 |  | 
 |   // Distribute loops to allow partial vectorization.  I.e. isolate dependences | 
 |   // into separate loop that would otherwise inhibit vectorization.  This is | 
 |   // currently only performed for loops marked with the metadata | 
 |   // llvm.loop.distribute=true or when -enable-loop-distribute is specified. | 
 |   MPM.add(createLoopDistributePass()); | 
 |  | 
 |   MPM.add(createLoopVectorizePass(!LoopsInterleaved, !LoopVectorize)); | 
 |  | 
 |   // Eliminate loads by forwarding stores from the previous iteration to loads | 
 |   // of the current iteration. | 
 |   MPM.add(createLoopLoadEliminationPass()); | 
 |  | 
 |   // FIXME: Because of #pragma vectorize enable, the passes below are always | 
 |   // inserted in the pipeline, even when the vectorizer doesn't run (ex. when | 
 |   // on -O1 and no #pragma is found). Would be good to have these two passes | 
 |   // as function calls, so that we can only pass them when the vectorizer | 
 |   // changed the code. | 
 |   addInstructionCombiningPass(MPM); | 
 |   if (OptLevel > 1 && ExtraVectorizerPasses) { | 
 |     // At higher optimization levels, try to clean up any runtime overlap and | 
 |     // alignment checks inserted by the vectorizer. We want to track correllated | 
 |     // runtime checks for two inner loops in the same outer loop, fold any | 
 |     // common computations, hoist loop-invariant aspects out of any outer loop, | 
 |     // and unswitch the runtime checks if possible. Once hoisted, we may have | 
 |     // dead (or speculatable) control flows or more combining opportunities. | 
 |     MPM.add(createEarlyCSEPass()); | 
 |     MPM.add(createCorrelatedValuePropagationPass()); | 
 |     addInstructionCombiningPass(MPM); | 
 |     MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap)); | 
 |     MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3, DivergentTarget)); | 
 |     MPM.add(createCFGSimplificationPass()); | 
 |     addInstructionCombiningPass(MPM); | 
 |   } | 
 |  | 
 |   // Cleanup after loop vectorization, etc. Simplification passes like CVP and | 
 |   // GVN, loop transforms, and others have already run, so it's now better to | 
 |   // convert to more optimized IR using more aggressive simplify CFG options. | 
 |   // The extra sinking transform can create larger basic blocks, so do this | 
 |   // before SLP vectorization. | 
 |   MPM.add(createCFGSimplificationPass(1, true, true, false, true)); | 
 |  | 
 |   if (SLPVectorize) { | 
 |     MPM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains. | 
 |     if (OptLevel > 1 && ExtraVectorizerPasses) { | 
 |       MPM.add(createEarlyCSEPass()); | 
 |     } | 
 |   } | 
 |  | 
 |   addExtensionsToPM(EP_Peephole, MPM); | 
 |   addInstructionCombiningPass(MPM); | 
 |  | 
 |   if (EnableUnrollAndJam && !DisableUnrollLoops) { | 
 |     // Unroll and Jam. We do this before unroll but need to be in a separate | 
 |     // loop pass manager in order for the outer loop to be processed by | 
 |     // unroll and jam before the inner loop is unrolled. | 
 |     MPM.add(createLoopUnrollAndJamPass(OptLevel)); | 
 |   } | 
 |  | 
 |   // Unroll small loops | 
 |   MPM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops, | 
 |                                ForgetAllSCEVInLoopUnroll)); | 
 |  | 
 |   if (!DisableUnrollLoops) { | 
 |     // LoopUnroll may generate some redundency to cleanup. | 
 |     addInstructionCombiningPass(MPM); | 
 |  | 
 |     // Runtime unrolling will introduce runtime check in loop prologue. If the | 
 |     // unrolled loop is a inner loop, then the prologue will be inside the | 
 |     // outer loop. LICM pass can help to promote the runtime check out if the | 
 |     // checked value is loop invariant. | 
 |     MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap)); | 
 |   } | 
 |  | 
 |   MPM.add(createWarnMissedTransformationsPass()); | 
 |  | 
 |   // After vectorization and unrolling, assume intrinsics may tell us more | 
 |   // about pointer alignments. | 
 |   MPM.add(createAlignmentFromAssumptionsPass()); | 
 |  | 
 |   // FIXME: We shouldn't bother with this anymore. | 
 |   MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes | 
 |  | 
 |   // GlobalOpt already deletes dead functions and globals, at -O2 try a | 
 |   // late pass of GlobalDCE.  It is capable of deleting dead cycles. | 
 |   if (OptLevel > 1) { | 
 |     MPM.add(createGlobalDCEPass());         // Remove dead fns and globals. | 
 |     MPM.add(createConstantMergePass());     // Merge dup global constants | 
 |   } | 
 |  | 
 |   // See comment in the new PM for justification of scheduling splitting at | 
 |   // this stage (\ref buildModuleSimplificationPipeline). | 
 |   if (EnableHotColdSplit && !(PrepareForLTO || PrepareForThinLTO)) | 
 |     MPM.add(createHotColdSplittingPass()); | 
 |  | 
 |   if (MergeFunctions) | 
 |     MPM.add(createMergeFunctionsPass()); | 
 |  | 
 |   // LoopSink pass sinks instructions hoisted by LICM, which serves as a | 
 |   // canonicalization pass that enables other optimizations. As a result, | 
 |   // LoopSink pass needs to be a very late IR pass to avoid undoing LICM | 
 |   // result too early. | 
 |   MPM.add(createLoopSinkPass()); | 
 |   // Get rid of LCSSA nodes. | 
 |   MPM.add(createInstSimplifyLegacyPass()); | 
 |  | 
 |   // This hoists/decomposes div/rem ops. It should run after other sink/hoist | 
 |   // passes to avoid re-sinking, but before SimplifyCFG because it can allow | 
 |   // flattening of blocks. | 
 |   MPM.add(createDivRemPairsPass()); | 
 |  | 
 |   // LoopSink (and other loop passes since the last simplifyCFG) might have | 
 |   // resulted in single-entry-single-exit or empty blocks. Clean up the CFG. | 
 |   MPM.add(createCFGSimplificationPass()); | 
 |  | 
 |   addExtensionsToPM(EP_OptimizerLast, MPM); | 
 |  | 
 |   if (PrepareForLTO) { | 
 |     MPM.add(createCanonicalizeAliasesPass()); | 
 |     // Rename anon globals to be able to handle them in the summary | 
 |     MPM.add(createNameAnonGlobalPass()); | 
 |   } | 
 | } | 
 |  | 
 | void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) { | 
 |   // Load sample profile before running the LTO optimization pipeline. | 
 |   if (!PGOSampleUse.empty()) { | 
 |     PM.add(createPruneEHPass()); | 
 |     PM.add(createSampleProfileLoaderPass(PGOSampleUse)); | 
 |   } | 
 |  | 
 |   // Remove unused virtual tables to improve the quality of code generated by | 
 |   // whole-program devirtualization and bitset lowering. | 
 |   PM.add(createGlobalDCEPass()); | 
 |  | 
 |   // Provide AliasAnalysis services for optimizations. | 
 |   addInitialAliasAnalysisPasses(PM); | 
 |  | 
 |   // Allow forcing function attributes as a debugging and tuning aid. | 
 |   PM.add(createForceFunctionAttrsLegacyPass()); | 
 |  | 
 |   // Infer attributes about declarations if possible. | 
 |   PM.add(createInferFunctionAttrsLegacyPass()); | 
 |  | 
 |   if (OptLevel > 1) { | 
 |     // 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())); | 
 |  | 
 |     // Propagate constants at call sites into the functions they call.  This | 
 |     // opens opportunities for globalopt (and inlining) by substituting function | 
 |     // pointers passed as arguments to direct uses of functions. | 
 |     PM.add(createIPSCCPPass()); | 
 |  | 
 |     // Attach metadata to indirect call sites indicating the set of functions | 
 |     // they may target at run-time. This should follow IPSCCP. | 
 |     PM.add(createCalledValuePropagationPass()); | 
 |  | 
 |     // Infer attributes on declarations, call sites, arguments, etc. | 
 |     PM.add(createAttributorLegacyPass()); | 
 |   } | 
 |  | 
 |   // Infer attributes about definitions. The readnone attribute in particular is | 
 |   // required for virtual constant propagation. | 
 |   PM.add(createPostOrderFunctionAttrsLegacyPass()); | 
 |   PM.add(createReversePostOrderFunctionAttrsPass()); | 
 |  | 
 |   // Split globals using inrange annotations on GEP indices. This can help | 
 |   // improve the quality of generated code when virtual constant propagation or | 
 |   // control flow integrity are enabled. | 
 |   PM.add(createGlobalSplitPass()); | 
 |  | 
 |   // Apply whole-program devirtualization and virtual constant propagation. | 
 |   PM.add(createWholeProgramDevirtPass(ExportSummary, nullptr)); | 
 |  | 
 |   // That's all we need at opt level 1. | 
 |   if (OptLevel == 1) | 
 |     return; | 
 |  | 
 |   // Now that we internalized some globals, see if we can hack on them! | 
 |   PM.add(createGlobalOptimizerPass()); | 
 |   // Promote any localized global vars. | 
 |   PM.add(createPromoteMemoryToRegisterPass()); | 
 |  | 
 |   // Linking modules together can lead to duplicated global constants, only | 
 |   // keep one copy of each constant. | 
 |   PM.add(createConstantMergePass()); | 
 |  | 
 |   // Remove unused arguments from functions. | 
 |   PM.add(createDeadArgEliminationPass()); | 
 |  | 
 |   // Reduce the code after globalopt and ipsccp.  Both can open up significant | 
 |   // simplification opportunities, and both can propagate functions through | 
 |   // function pointers.  When this happens, we often have to resolve varargs | 
 |   // calls, etc, so let instcombine do this. | 
 |   if (OptLevel > 2) | 
 |     PM.add(createAggressiveInstCombinerPass()); | 
 |   addInstructionCombiningPass(PM); | 
 |   addExtensionsToPM(EP_Peephole, PM); | 
 |  | 
 |   // Inline small functions | 
 |   bool RunInliner = Inliner; | 
 |   if (RunInliner) { | 
 |     PM.add(Inliner); | 
 |     Inliner = nullptr; | 
 |   } | 
 |  | 
 |   PM.add(createPruneEHPass());   // Remove dead EH info. | 
 |  | 
 |   // CSFDO instrumentation and use pass. | 
 |   addPGOInstrPasses(PM, /* IsCS */ true); | 
 |  | 
 |   // Optimize globals again if we ran the inliner. | 
 |   if (RunInliner) | 
 |     PM.add(createGlobalOptimizerPass()); | 
 |   PM.add(createGlobalDCEPass()); // Remove dead functions. | 
 |  | 
 |   // If we didn't decide to inline a function, check to see if we can | 
 |   // transform it to pass arguments by value instead of by reference. | 
 |   PM.add(createArgumentPromotionPass()); | 
 |  | 
 |   // The IPO passes may leave cruft around.  Clean up after them. | 
 |   addInstructionCombiningPass(PM); | 
 |   addExtensionsToPM(EP_Peephole, PM); | 
 |   PM.add(createJumpThreadingPass()); | 
 |  | 
 |   // Break up allocas | 
 |   PM.add(createSROAPass()); | 
 |  | 
 |   // LTO provides additional opportunities for tailcall elimination due to | 
 |   // link-time inlining, and visibility of nocapture attribute. | 
 |   if (OptLevel > 1) | 
 |     PM.add(createTailCallEliminationPass()); | 
 |  | 
 |   // Infer attributes on declarations, call sites, arguments, etc. | 
 |   PM.add(createPostOrderFunctionAttrsLegacyPass()); // Add nocapture. | 
 |   // Run a few AA driven optimizations here and now, to cleanup the code. | 
 |   PM.add(createGlobalsAAWrapperPass()); // IP alias analysis. | 
 |  | 
 |   PM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap)); | 
 |   PM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds. | 
 |   PM.add(NewGVN ? createNewGVNPass() | 
 |                 : createGVNPass(DisableGVNLoadPRE)); // Remove redundancies. | 
 |   PM.add(createMemCpyOptPass());            // Remove dead memcpys. | 
 |  | 
 |   // Nuke dead stores. | 
 |   PM.add(createDeadStoreEliminationPass()); | 
 |  | 
 |   // More loops are countable; try to optimize them. | 
 |   PM.add(createIndVarSimplifyPass()); | 
 |   PM.add(createLoopDeletionPass()); | 
 |   if (EnableLoopInterchange) | 
 |     PM.add(createLoopInterchangePass()); | 
 |  | 
 |   // Unroll small loops | 
 |   PM.add(createSimpleLoopUnrollPass(OptLevel, DisableUnrollLoops, | 
 |                                     ForgetAllSCEVInLoopUnroll)); | 
 |   PM.add(createLoopVectorizePass(true, !LoopVectorize)); | 
 |   // The vectorizer may have significantly shortened a loop body; unroll again. | 
 |   PM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops, | 
 |                               ForgetAllSCEVInLoopUnroll)); | 
 |  | 
 |   PM.add(createWarnMissedTransformationsPass()); | 
 |  | 
 |   // Now that we've optimized loops (in particular loop induction variables), | 
 |   // we may have exposed more scalar opportunities. Run parts of the scalar | 
 |   // optimizer again at this point. | 
 |   addInstructionCombiningPass(PM); // Initial cleanup | 
 |   PM.add(createCFGSimplificationPass()); // if-convert | 
 |   PM.add(createSCCPPass()); // Propagate exposed constants | 
 |   addInstructionCombiningPass(PM); // Clean up again | 
 |   PM.add(createBitTrackingDCEPass()); | 
 |  | 
 |   // More scalar chains could be vectorized due to more alias information | 
 |   if (SLPVectorize) | 
 |     PM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains. | 
 |  | 
 |   // After vectorization, assume intrinsics may tell us more about pointer | 
 |   // alignments. | 
 |   PM.add(createAlignmentFromAssumptionsPass()); | 
 |  | 
 |   // Cleanup and simplify the code after the scalar optimizations. | 
 |   addInstructionCombiningPass(PM); | 
 |   addExtensionsToPM(EP_Peephole, PM); | 
 |  | 
 |   PM.add(createJumpThreadingPass()); | 
 | } | 
 |  | 
 | void PassManagerBuilder::addLateLTOOptimizationPasses( | 
 |     legacy::PassManagerBase &PM) { | 
 |   // See comment in the new PM for justification of scheduling splitting at | 
 |   // this stage (\ref buildLTODefaultPipeline). | 
 |   if (EnableHotColdSplit) | 
 |     PM.add(createHotColdSplittingPass()); | 
 |  | 
 |   // Delete basic blocks, which optimization passes may have killed. | 
 |   PM.add(createCFGSimplificationPass()); | 
 |  | 
 |   // Drop bodies of available externally objects to improve GlobalDCE. | 
 |   PM.add(createEliminateAvailableExternallyPass()); | 
 |  | 
 |   // Now that we have optimized the program, discard unreachable functions. | 
 |   PM.add(createGlobalDCEPass()); | 
 |  | 
 |   // FIXME: this is profitable (for compiler time) to do at -O0 too, but | 
 |   // currently it damages debug info. | 
 |   if (MergeFunctions) | 
 |     PM.add(createMergeFunctionsPass()); | 
 | } | 
 |  | 
 | void PassManagerBuilder::populateThinLTOPassManager( | 
 |     legacy::PassManagerBase &PM) { | 
 |   PerformThinLTO = true; | 
 |   if (LibraryInfo) | 
 |     PM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); | 
 |  | 
 |   if (VerifyInput) | 
 |     PM.add(createVerifierPass()); | 
 |  | 
 |   if (ImportSummary) { | 
 |     // These passes import type identifier resolutions for whole-program | 
 |     // devirtualization and CFI. They must run early because other passes may | 
 |     // disturb the specific instruction patterns that these passes look for, | 
 |     // creating dependencies on resolutions that may not appear in the summary. | 
 |     // | 
 |     // For example, GVN may transform the pattern assume(type.test) appearing in | 
 |     // two basic blocks into assume(phi(type.test, type.test)), which would | 
 |     // transform a dependency on a WPD resolution into a dependency on a type | 
 |     // identifier resolution for CFI. | 
 |     // | 
 |     // Also, WPD has access to more precise information than ICP and can | 
 |     // devirtualize more effectively, so it should operate on the IR first. | 
 |     PM.add(createWholeProgramDevirtPass(nullptr, ImportSummary)); | 
 |     PM.add(createLowerTypeTestsPass(nullptr, ImportSummary)); | 
 |   } | 
 |  | 
 |   populateModulePassManager(PM); | 
 |  | 
 |   if (VerifyOutput) | 
 |     PM.add(createVerifierPass()); | 
 |   PerformThinLTO = false; | 
 | } | 
 |  | 
 | void PassManagerBuilder::populateLTOPassManager(legacy::PassManagerBase &PM) { | 
 |   if (LibraryInfo) | 
 |     PM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); | 
 |  | 
 |   if (VerifyInput) | 
 |     PM.add(createVerifierPass()); | 
 |  | 
 |   addExtensionsToPM(EP_FullLinkTimeOptimizationEarly, PM); | 
 |  | 
 |   if (OptLevel != 0) | 
 |     addLTOOptimizationPasses(PM); | 
 |   else { | 
 |     // The whole-program-devirt pass needs to run at -O0 because only it knows | 
 |     // about the llvm.type.checked.load intrinsic: it needs to both lower the | 
 |     // intrinsic itself and handle it in the summary. | 
 |     PM.add(createWholeProgramDevirtPass(ExportSummary, nullptr)); | 
 |   } | 
 |  | 
 |   // Create a function that performs CFI checks for cross-DSO calls with targets | 
 |   // in the current module. | 
 |   PM.add(createCrossDSOCFIPass()); | 
 |  | 
 |   // Lower type metadata and the type.test intrinsic. This pass supports Clang's | 
 |   // control flow integrity mechanisms (-fsanitize=cfi*) and needs to run at | 
 |   // link time if CFI is enabled. The pass does nothing if CFI is disabled. | 
 |   PM.add(createLowerTypeTestsPass(ExportSummary, nullptr)); | 
 |  | 
 |   if (OptLevel != 0) | 
 |     addLateLTOOptimizationPasses(PM); | 
 |  | 
 |   addExtensionsToPM(EP_FullLinkTimeOptimizationLast, PM); | 
 |  | 
 |   if (VerifyOutput) | 
 |     PM.add(createVerifierPass()); | 
 | } | 
 |  | 
 | inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) { | 
 |     return reinterpret_cast<PassManagerBuilder*>(P); | 
 | } | 
 |  | 
 | inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) { | 
 |   return reinterpret_cast<LLVMPassManagerBuilderRef>(P); | 
 | } | 
 |  | 
 | LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() { | 
 |   PassManagerBuilder *PMB = new PassManagerBuilder(); | 
 |   return wrap(PMB); | 
 | } | 
 |  | 
 | void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   delete Builder; | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB, | 
 |                                   unsigned OptLevel) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   Builder->OptLevel = OptLevel; | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB, | 
 |                                    unsigned SizeLevel) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   Builder->SizeLevel = SizeLevel; | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB, | 
 |                                             LLVMBool Value) { | 
 |   // NOTE: The DisableUnitAtATime switch has been removed. | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB, | 
 |                                             LLVMBool Value) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   Builder->DisableUnrollLoops = Value; | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB, | 
 |                                                  LLVMBool Value) { | 
 |   // NOTE: The simplify-libcalls pass has been removed. | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB, | 
 |                                               unsigned Threshold) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   Builder->Inliner = createFunctionInliningPass(Threshold); | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB, | 
 |                                                   LLVMPassManagerRef PM) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   legacy::FunctionPassManager *FPM = unwrap<legacy::FunctionPassManager>(PM); | 
 |   Builder->populateFunctionPassManager(*FPM); | 
 | } | 
 |  | 
 | void | 
 | LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB, | 
 |                                                 LLVMPassManagerRef PM) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   legacy::PassManagerBase *MPM = unwrap(PM); | 
 |   Builder->populateModulePassManager(*MPM); | 
 | } | 
 |  | 
 | void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB, | 
 |                                                   LLVMPassManagerRef PM, | 
 |                                                   LLVMBool Internalize, | 
 |                                                   LLVMBool RunInliner) { | 
 |   PassManagerBuilder *Builder = unwrap(PMB); | 
 |   legacy::PassManagerBase *LPM = unwrap(PM); | 
 |  | 
 |   // A small backwards compatibility hack. populateLTOPassManager used to take | 
 |   // an RunInliner option. | 
 |   if (RunInliner && !Builder->Inliner) | 
 |     Builder->Inliner = createFunctionInliningPass(); | 
 |  | 
 |   Builder->populateLTOPassManager(*LPM); | 
 | } |