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/InlineCost.h" 15 #include "llvm/Analysis/LazyCallGraph.h" 16 #include "llvm/IR/CallSite.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 bool doInitialization(CallGraph &CG) override; 40 41 /// Main run interface method, this implements the interface required by the 42 /// Pass class. 43 bool runOnSCC(CallGraphSCC &SCC) override; 44 45 using llvm::Pass::doFinalization; 46 47 /// Remove now-dead linkonce functions at the end of processing to avoid 48 /// breaking the SCC traversal. 49 bool doFinalization(CallGraph &CG) override; 50 51 /// This method must be implemented by the subclass to determine the cost of 52 /// inlining the specified call site. If the cost returned is greater than 53 /// the current inline threshold, the call site is not inlined. 54 virtual InlineCost getInlineCost(CallSite CS) = 0; 55 56 /// Remove dead functions. 57 /// 58 /// This also includes a hack in the form of the 'AlwaysInlineOnly' flag 59 /// which restricts it to deleting functions with an 'AlwaysInline' 60 /// attribute. This is useful for the InlineAlways pass that only wants to 61 /// deal with that subset of the functions. 62 bool removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly = false); 63 64 /// This function performs the main work of the pass. The default of 65 /// Inlinter::runOnSCC() calls skipSCC() before calling this method, but 66 /// derived classes which cannot be skipped can override that method and call 67 /// this function unconditionally. 68 bool inlineCalls(CallGraphSCC &SCC); 69 70 private: 71 // Insert @llvm.lifetime intrinsics. 72 bool InsertLifetime = true; 73 74 protected: 75 AssumptionCacheTracker *ACT; 76 ProfileSummaryInfo *PSI; 77 ImportedFunctionsInliningStatistics ImportedFunctionsStats; 78 }; 79 80 /// The inliner pass for the new pass manager. 81 /// 82 /// This pass wires together the inlining utilities and the inline cost 83 /// analysis into a CGSCC pass. It considers every call in every function in 84 /// the SCC and tries to inline if profitable. It can be tuned with a number of 85 /// parameters to control what cost model is used and what tradeoffs are made 86 /// when making the decision. 87 /// 88 /// It should be noted that the legacy inliners do considerably more than this 89 /// inliner pass does. They provide logic for manually merging allocas, and 90 /// doing considerable DCE including the DCE of dead functions. This pass makes 91 /// every attempt to be simpler. DCE of functions requires complex reasoning 92 /// about comdat groups, etc. Instead, it is expected that other more focused 93 /// passes be composed to achieve the same end result. 94 class InlinerPass : public PassInfoMixin<InlinerPass> { 95 public: 96 InlinerPass(InlineParams Params = getInlineParams()) Params(std::move (Params))97 : Params(std::move(Params)) {} 98 ~InlinerPass(); InlinerPass(InlinerPass && Arg)99 InlinerPass(InlinerPass &&Arg) 100 : Params(std::move(Arg.Params)), 101 ImportedFunctionsStats(std::move(Arg.ImportedFunctionsStats)) {} 102 103 PreservedAnalyses run(LazyCallGraph::SCC &C, CGSCCAnalysisManager &AM, 104 LazyCallGraph &CG, CGSCCUpdateResult &UR); 105 106 private: 107 InlineParams Params; 108 std::unique_ptr<ImportedFunctionsInliningStatistics> ImportedFunctionsStats; 109 }; 110 111 } // end namespace llvm 112 113 #endif // LLVM_TRANSFORMS_IPO_INLINER_H 114