1 //===- Inliner.h - Inliner pass and infrastructure --------------*- 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 9 #ifndef LLVM_TRANSFORMS_IPO_INLINER_H 10 #define LLVM_TRANSFORMS_IPO_INLINER_H 11 12 #include "llvm/Analysis/CGSCCPassManager.h" 13 #include "llvm/Analysis/CallGraphSCCPass.h" 14 #include "llvm/Analysis/InlineAdvisor.h" 15 #include "llvm/Analysis/InlineCost.h" 16 #include "llvm/Analysis/LazyCallGraph.h" 17 #include "llvm/IR/PassManager.h" 18 #include "llvm/Transforms/Utils/ImportedFunctionsInliningStatistics.h" 19 #include <utility> 20 21 namespace llvm { 22 23 class AssumptionCacheTracker; 24 class CallGraph; 25 class ProfileSummaryInfo; 26 27 /// This class contains all of the helper code which is used to perform the 28 /// inlining operations that do not depend on the policy. It contains the core 29 /// bottom-up inlining infrastructure that specific inliner passes use. 30 struct LegacyInlinerBase : public CallGraphSCCPass { 31 explicit LegacyInlinerBase(char &ID); 32 explicit LegacyInlinerBase(char &ID, bool InsertLifetime); 33 34 /// For this class, we declare that we require and preserve the call graph. 35 /// If the derived class implements this method, it should always explicitly 36 /// call the implementation here. 37 void getAnalysisUsage(AnalysisUsage &Info) const override; 38 39 using llvm::Pass::doInitialization; 40 41 bool doInitialization(CallGraph &CG) override; 42 43 /// Main run interface method, this implements the interface required by the 44 /// Pass class. 45 bool runOnSCC(CallGraphSCC &SCC) override; 46 47 using llvm::Pass::doFinalization; 48 49 /// Remove now-dead linkonce functions at the end of processing to avoid 50 /// breaking the SCC traversal. 51 bool doFinalization(CallGraph &CG) override; 52 53 /// This method must be implemented by the subclass to determine the cost of 54 /// inlining the specified call site. If the cost returned is greater than 55 /// the current inline threshold, the call site is not inlined. 56 virtual InlineCost getInlineCost(CallBase &CB) = 0; 57 58 /// Remove dead functions. 59 /// 60 /// This also includes a hack in the form of the 'AlwaysInlineOnly' flag 61 /// which restricts it to deleting functions with an 'AlwaysInline' 62 /// attribute. This is useful for the InlineAlways pass that only wants to 63 /// deal with that subset of the functions. 64 bool removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly = false); 65 66 /// This function performs the main work of the pass. The default of 67 /// Inlinter::runOnSCC() calls skipSCC() before calling this method, but 68 /// derived classes which cannot be skipped can override that method and call 69 /// this function unconditionally. 70 bool inlineCalls(CallGraphSCC &SCC); 71 72 private: 73 // Insert @llvm.lifetime intrinsics. 74 bool InsertLifetime = true; 75 76 protected: 77 AssumptionCacheTracker *ACT; 78 ProfileSummaryInfo *PSI; 79 std::function<const TargetLibraryInfo &(Function &)> GetTLI; 80 ImportedFunctionsInliningStatistics ImportedFunctionsStats; 81 }; 82 83 /// The inliner pass for the new pass manager. 84 /// 85 /// This pass wires together the inlining utilities and the inline cost 86 /// analysis into a CGSCC pass. It considers every call in every function in 87 /// the SCC and tries to inline if profitable. It can be tuned with a number of 88 /// parameters to control what cost model is used and what tradeoffs are made 89 /// when making the decision. 90 /// 91 /// It should be noted that the legacy inliners do considerably more than this 92 /// inliner pass does. They provide logic for manually merging allocas, and 93 /// doing considerable DCE including the DCE of dead functions. This pass makes 94 /// every attempt to be simpler. DCE of functions requires complex reasoning 95 /// about comdat groups, etc. Instead, it is expected that other more focused 96 /// passes be composed to achieve the same end result. 97 class InlinerPass : public PassInfoMixin<InlinerPass> { 98 public: 99 InlinerPass() = default; 100 ~InlinerPass(); InlinerPass(InlinerPass && Arg)101 InlinerPass(InlinerPass &&Arg) 102 : ImportedFunctionsStats(std::move(Arg.ImportedFunctionsStats)) {} 103 104 PreservedAnalyses run(LazyCallGraph::SCC &C, CGSCCAnalysisManager &AM, 105 LazyCallGraph &CG, CGSCCUpdateResult &UR); 106 107 private: 108 InlineAdvisor &getAdvisor(const ModuleAnalysisManagerCGSCCProxy::Result &MAM, 109 FunctionAnalysisManager &FAM, Module &M); 110 std::unique_ptr<ImportedFunctionsInliningStatistics> ImportedFunctionsStats; 111 Optional<DefaultInlineAdvisor> OwnedDefaultAdvisor; 112 }; 113 114 /// Module pass, wrapping the inliner pass. This works in conjunction with the 115 /// InlineAdvisorAnalysis to facilitate inlining decisions taking into account 116 /// module-wide state, that need to keep track of inter-inliner pass runs, for 117 /// a given module. An InlineAdvisor is configured and kept alive for the 118 /// duration of the ModuleInlinerWrapperPass::run. 119 class ModuleInlinerWrapperPass 120 : public PassInfoMixin<ModuleInlinerWrapperPass> { 121 public: 122 ModuleInlinerWrapperPass( 123 InlineParams Params = getInlineParams(), bool Debugging = false, 124 InliningAdvisorMode Mode = InliningAdvisorMode::Default, 125 unsigned MaxDevirtIterations = 0); 126 ModuleInlinerWrapperPass(ModuleInlinerWrapperPass &&Arg) = default; 127 128 PreservedAnalyses run(Module &, ModuleAnalysisManager &); 129 130 /// Allow adding more CGSCC passes, besides inlining. This should be called 131 /// before run is called, as part of pass pipeline building. getPM()132 CGSCCPassManager &getPM() { return PM; } 133 134 /// Allow adding module-level analyses benefiting the contained CGSCC passes. addRequiredModuleAnalysis()135 template <class T> void addRequiredModuleAnalysis() { 136 MPM.addPass(RequireAnalysisPass<T, Module>()); 137 } 138 139 private: 140 const InlineParams Params; 141 const InliningAdvisorMode Mode; 142 const unsigned MaxDevirtIterations; 143 CGSCCPassManager PM; 144 ModulePassManager MPM; 145 }; 146 } // end namespace llvm 147 148 #endif // LLVM_TRANSFORMS_IPO_INLINER_H 149