| //===- OptimizationRemarkEmitter.h - Optimization Diagnostic ----*- 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Optimization diagnostic interfaces. It's packaged as an analysis pass so |
| // that by using this service passes become dependent on BFI as well. BFI is |
| // used to compute the "hotness" of the diagnostic message. |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_IR_OPTIMIZATIONDIAGNOSTICINFO_H |
| #define LLVM_IR_OPTIMIZATIONDIAGNOSTICINFO_H |
| |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/Analysis/BlockFrequencyInfo.h" |
| #include "llvm/IR/DiagnosticInfo.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/PassManager.h" |
| #include "llvm/Pass.h" |
| |
| namespace llvm { |
| class DebugLoc; |
| class Loop; |
| class Pass; |
| class Twine; |
| class Value; |
| |
| /// The optimization diagnostic interface. |
| /// |
| /// It allows reporting when optimizations are performed and when they are not |
| /// along with the reasons for it. Hotness information of the corresponding |
| /// code region can be included in the remark if DiagnosticsHotnessRequested is |
| /// enabled in the LLVM context. |
| class OptimizationRemarkEmitter { |
| public: |
| OptimizationRemarkEmitter(const Function *F, BlockFrequencyInfo *BFI) |
| : F(F), BFI(BFI) {} |
| |
| /// This variant can be used to generate ORE on demand (without the |
| /// analysis pass). |
| /// |
| /// Note that this ctor has a very different cost depending on whether |
| /// F->getContext().getDiagnosticsHotnessRequested() is on or not. If it's off |
| /// the operation is free. |
| /// |
| /// Whereas if DiagnosticsHotnessRequested is on, it is fairly expensive |
| /// operation since BFI and all its required analyses are computed. This is |
| /// for example useful for CGSCC passes that can't use function analyses |
| /// passes in the old PM. |
| OptimizationRemarkEmitter(const Function *F); |
| |
| OptimizationRemarkEmitter(OptimizationRemarkEmitter &&Arg) |
| : F(Arg.F), BFI(Arg.BFI) {} |
| |
| OptimizationRemarkEmitter &operator=(OptimizationRemarkEmitter &&RHS) { |
| F = RHS.F; |
| BFI = RHS.BFI; |
| return *this; |
| } |
| |
| /// Handle invalidation events in the new pass manager. |
| bool invalidate(Function &F, const PreservedAnalyses &PA, |
| FunctionAnalysisManager::Invalidator &Inv); |
| |
| /// Output the remark via the diagnostic handler and to the |
| /// optimization record file. |
| void emit(DiagnosticInfoOptimizationBase &OptDiag); |
| |
| /// Take a lambda that returns a remark which will be emitted. Second |
| /// argument is only used to restrict this to functions. |
| template <typename T> |
| void emit(T RemarkBuilder, decltype(RemarkBuilder()) * = nullptr) { |
| // Avoid building the remark unless we know there are at least *some* |
| // remarks enabled. We can't currently check whether remarks are requested |
| // for the calling pass since that requires actually building the remark. |
| |
| if (F->getContext().getRemarkStreamer() || |
| F->getContext().getDiagHandlerPtr()->isAnyRemarkEnabled()) { |
| auto R = RemarkBuilder(); |
| emit((DiagnosticInfoOptimizationBase &)R); |
| } |
| } |
| |
| /// Whether we allow for extra compile-time budget to perform more |
| /// analysis to produce fewer false positives. |
| /// |
| /// This is useful when reporting missed optimizations. In this case we can |
| /// use the extra analysis (1) to filter trivial false positives or (2) to |
| /// provide more context so that non-trivial false positives can be quickly |
| /// detected by the user. |
| bool allowExtraAnalysis(StringRef PassName) const { |
| return (F->getContext().getRemarkStreamer() || |
| F->getContext().getDiagHandlerPtr()->isAnyRemarkEnabled(PassName)); |
| } |
| |
| private: |
| const Function *F; |
| |
| BlockFrequencyInfo *BFI; |
| |
| /// If we generate BFI on demand, we need to free it when ORE is freed. |
| std::unique_ptr<BlockFrequencyInfo> OwnedBFI; |
| |
| /// Compute hotness from IR value (currently assumed to be a block) if PGO is |
| /// available. |
| Optional<uint64_t> computeHotness(const Value *V); |
| |
| /// Similar but use value from \p OptDiag and update hotness there. |
| void computeHotness(DiagnosticInfoIROptimization &OptDiag); |
| |
| /// Only allow verbose messages if we know we're filtering by hotness |
| /// (BFI is only set in this case). |
| bool shouldEmitVerbose() { return BFI != nullptr; } |
| |
| OptimizationRemarkEmitter(const OptimizationRemarkEmitter &) = delete; |
| void operator=(const OptimizationRemarkEmitter &) = delete; |
| }; |
| |
| /// Add a small namespace to avoid name clashes with the classes used in |
| /// the streaming interface. We want these to be short for better |
| /// write/readability. |
| namespace ore { |
| using NV = DiagnosticInfoOptimizationBase::Argument; |
| using setIsVerbose = DiagnosticInfoOptimizationBase::setIsVerbose; |
| using setExtraArgs = DiagnosticInfoOptimizationBase::setExtraArgs; |
| } |
| |
| /// OptimizationRemarkEmitter legacy analysis pass |
| /// |
| /// Note that this pass shouldn't generally be marked as preserved by other |
| /// passes. It's holding onto BFI, so if the pass does not preserve BFI, BFI |
| /// could be freed. |
| class OptimizationRemarkEmitterWrapperPass : public FunctionPass { |
| std::unique_ptr<OptimizationRemarkEmitter> ORE; |
| |
| public: |
| OptimizationRemarkEmitterWrapperPass(); |
| |
| bool runOnFunction(Function &F) override; |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override; |
| |
| OptimizationRemarkEmitter &getORE() { |
| assert(ORE && "pass not run yet"); |
| return *ORE; |
| } |
| |
| static char ID; |
| }; |
| |
| class OptimizationRemarkEmitterAnalysis |
| : public AnalysisInfoMixin<OptimizationRemarkEmitterAnalysis> { |
| friend AnalysisInfoMixin<OptimizationRemarkEmitterAnalysis>; |
| static AnalysisKey Key; |
| |
| public: |
| /// Provide the result typedef for this analysis pass. |
| typedef OptimizationRemarkEmitter Result; |
| |
| /// Run the analysis pass over a function and produce BFI. |
| Result run(Function &F, FunctionAnalysisManager &AM); |
| }; |
| } |
| #endif // LLVM_IR_OPTIMIZATIONDIAGNOSTICINFO_H |