1 //===- LoopAnalysisManager.h - Loop analysis management ---------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// \file 9 /// 10 /// This header provides classes for managing per-loop analyses. These are 11 /// typically used as part of a loop pass pipeline over the loop nests of 12 /// a function. 13 /// 14 /// Loop analyses are allowed to make some simplifying assumptions: 15 /// 1) Loops are, where possible, in simplified form. 16 /// 2) Loops are *always* in LCSSA form. 17 /// 3) A collection of analysis results are available: 18 /// - LoopInfo 19 /// - DominatorTree 20 /// - ScalarEvolution 21 /// - AAManager 22 /// 23 /// The primary mechanism to provide these invariants is the loop pass manager, 24 /// but they can also be manually provided in order to reason about a loop from 25 /// outside of a dedicated pass manager. 26 /// 27 //===----------------------------------------------------------------------===// 28 29 #ifndef LLVM_ANALYSIS_LOOPANALYSISMANAGER_H 30 #define LLVM_ANALYSIS_LOOPANALYSISMANAGER_H 31 32 #include "llvm/ADT/PostOrderIterator.h" 33 #include "llvm/IR/PassManager.h" 34 35 namespace llvm { 36 37 class AAResults; 38 class AssumptionCache; 39 class DominatorTree; 40 class Function; 41 class Loop; 42 class LoopInfo; 43 class MemorySSA; 44 class ScalarEvolution; 45 class TargetLibraryInfo; 46 class TargetTransformInfo; 47 48 /// The adaptor from a function pass to a loop pass computes these analyses and 49 /// makes them available to the loop passes "for free". Each loop pass is 50 /// expected to update these analyses if necessary to ensure they're 51 /// valid after it runs. 52 struct LoopStandardAnalysisResults { 53 AAResults &AA; 54 AssumptionCache &AC; 55 DominatorTree &DT; 56 LoopInfo &LI; 57 ScalarEvolution &SE; 58 TargetLibraryInfo &TLI; 59 TargetTransformInfo &TTI; 60 BlockFrequencyInfo *BFI; 61 MemorySSA *MSSA; 62 }; 63 64 /// Extern template declaration for the analysis set for this IR unit. 65 extern template class AllAnalysesOn<Loop>; 66 67 extern template class AnalysisManager<Loop, LoopStandardAnalysisResults &>; 68 /// The loop analysis manager. 69 /// 70 /// See the documentation for the AnalysisManager template for detail 71 /// documentation. This typedef serves as a convenient way to refer to this 72 /// construct in the adaptors and proxies used to integrate this into the larger 73 /// pass manager infrastructure. 74 typedef AnalysisManager<Loop, LoopStandardAnalysisResults &> 75 LoopAnalysisManager; 76 77 /// A proxy from a \c LoopAnalysisManager to a \c Function. 78 typedef InnerAnalysisManagerProxy<LoopAnalysisManager, Function> 79 LoopAnalysisManagerFunctionProxy; 80 81 /// A specialized result for the \c LoopAnalysisManagerFunctionProxy which 82 /// retains a \c LoopInfo reference. 83 /// 84 /// This allows it to collect loop objects for which analysis results may be 85 /// cached in the \c LoopAnalysisManager. 86 template <> class LoopAnalysisManagerFunctionProxy::Result { 87 public: 88 explicit Result(LoopAnalysisManager &InnerAM, LoopInfo &LI) 89 : InnerAM(&InnerAM), LI(&LI), MSSAUsed(false) {} 90 Result(Result &&Arg) 91 : InnerAM(std::move(Arg.InnerAM)), LI(Arg.LI), MSSAUsed(Arg.MSSAUsed) { 92 // We have to null out the analysis manager in the moved-from state 93 // because we are taking ownership of the responsibilty to clear the 94 // analysis state. 95 Arg.InnerAM = nullptr; 96 } 97 Result &operator=(Result &&RHS) { 98 InnerAM = RHS.InnerAM; 99 LI = RHS.LI; 100 MSSAUsed = RHS.MSSAUsed; 101 // We have to null out the analysis manager in the moved-from state 102 // because we are taking ownership of the responsibilty to clear the 103 // analysis state. 104 RHS.InnerAM = nullptr; 105 return *this; 106 } 107 ~Result() { 108 // InnerAM is cleared in a moved from state where there is nothing to do. 109 if (!InnerAM) 110 return; 111 112 // Clear out the analysis manager if we're being destroyed -- it means we 113 // didn't even see an invalidate call when we got invalidated. 114 InnerAM->clear(); 115 } 116 117 /// Mark MemorySSA as used so we can invalidate self if MSSA is invalidated. 118 void markMSSAUsed() { MSSAUsed = true; } 119 120 /// Accessor for the analysis manager. 121 LoopAnalysisManager &getManager() { return *InnerAM; } 122 123 /// Handler for invalidation of the proxy for a particular function. 124 /// 125 /// If the proxy, \c LoopInfo, and associated analyses are preserved, this 126 /// will merely forward the invalidation event to any cached loop analysis 127 /// results for loops within this function. 128 /// 129 /// If the necessary loop infrastructure is not preserved, this will forcibly 130 /// clear all of the cached analysis results that are keyed on the \c 131 /// LoopInfo for this function. 132 bool invalidate(Function &F, const PreservedAnalyses &PA, 133 FunctionAnalysisManager::Invalidator &Inv); 134 135 private: 136 LoopAnalysisManager *InnerAM; 137 LoopInfo *LI; 138 bool MSSAUsed; 139 }; 140 141 /// Provide a specialized run method for the \c LoopAnalysisManagerFunctionProxy 142 /// so it can pass the \c LoopInfo to the result. 143 template <> 144 LoopAnalysisManagerFunctionProxy::Result 145 LoopAnalysisManagerFunctionProxy::run(Function &F, FunctionAnalysisManager &AM); 146 147 // Ensure the \c LoopAnalysisManagerFunctionProxy is provided as an extern 148 // template. 149 extern template class InnerAnalysisManagerProxy<LoopAnalysisManager, Function>; 150 151 extern template class OuterAnalysisManagerProxy<FunctionAnalysisManager, Loop, 152 LoopStandardAnalysisResults &>; 153 /// A proxy from a \c FunctionAnalysisManager to a \c Loop. 154 typedef OuterAnalysisManagerProxy<FunctionAnalysisManager, Loop, 155 LoopStandardAnalysisResults &> 156 FunctionAnalysisManagerLoopProxy; 157 158 /// Returns the minimum set of Analyses that all loop passes must preserve. 159 PreservedAnalyses getLoopPassPreservedAnalyses(); 160 } 161 162 #endif // LLVM_ANALYSIS_LOOPANALYSISMANAGER_H 163