1 //===- ReplayInlineAdvisor.cpp - Replay InlineAdvisor ---------------------===// 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 // This file implements ReplayInlineAdvisor that replays inline decisions based 10 // on previous inline remarks from optimization remark log. This is a best 11 // effort approach useful for testing compiler/source changes while holding 12 // inlining steady. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "llvm/Analysis/ReplayInlineAdvisor.h" 17 #include "llvm/IR/DebugInfoMetadata.h" 18 #include "llvm/IR/Instructions.h" 19 #include "llvm/Support/LineIterator.h" 20 #include <memory> 21 22 using namespace llvm; 23 24 #define DEBUG_TYPE "replay-inline" 25 26 ReplayInlineAdvisor::ReplayInlineAdvisor( 27 Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context, 28 std::unique_ptr<InlineAdvisor> OriginalAdvisor, 29 const ReplayInlinerSettings &ReplaySettings, bool EmitRemarks) 30 : InlineAdvisor(M, FAM), OriginalAdvisor(std::move(OriginalAdvisor)), 31 HasReplayRemarks(false), ReplaySettings(ReplaySettings), 32 EmitRemarks(EmitRemarks) { 33 34 auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(ReplaySettings.ReplayFile); 35 std::error_code EC = BufferOrErr.getError(); 36 if (EC) { 37 Context.emitError("Could not open remarks file: " + EC.message()); 38 return; 39 } 40 41 // Example for inline remarks to parse: 42 // main:3:1.1: '_Z3subii' inlined into 'main' at callsite sum:1 @ 43 // main:3:1.1; 44 // We use the callsite string after `at callsite` to replay inlining. 45 line_iterator LineIt(*BufferOrErr.get(), /*SkipBlanks=*/true); 46 const std::string PositiveRemark = "' inlined into '"; 47 const std::string NegativeRemark = "' will not be inlined into '"; 48 49 for (; !LineIt.is_at_eof(); ++LineIt) { 50 StringRef Line = *LineIt; 51 auto Pair = Line.split(" at callsite "); 52 53 bool IsPositiveRemark = true; 54 if (Pair.first.contains(NegativeRemark)) 55 IsPositiveRemark = false; 56 57 auto CalleeCaller = 58 Pair.first.split(IsPositiveRemark ? PositiveRemark : NegativeRemark); 59 60 StringRef Callee = CalleeCaller.first.rsplit(": '").second; 61 StringRef Caller = CalleeCaller.second.rsplit("'").first; 62 63 auto CallSite = Pair.second.split(";").first; 64 65 if (Callee.empty() || Caller.empty() || CallSite.empty()) { 66 Context.emitError("Invalid remark format: " + Line); 67 return; 68 } 69 70 std::string Combined = (Callee + CallSite).str(); 71 InlineSitesFromRemarks[Combined] = IsPositiveRemark; 72 if (ReplaySettings.ReplayScope == ReplayInlinerSettings::Scope::Function) 73 CallersToReplay.insert(Caller); 74 } 75 76 HasReplayRemarks = true; 77 } 78 79 std::unique_ptr<InlineAdvisor> llvm::getReplayInlineAdvisor( 80 Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context, 81 std::unique_ptr<InlineAdvisor> OriginalAdvisor, 82 const ReplayInlinerSettings &ReplaySettings, bool EmitRemarks) { 83 auto Advisor = std::make_unique<ReplayInlineAdvisor>( 84 M, FAM, Context, std::move(OriginalAdvisor), ReplaySettings, EmitRemarks); 85 if (!Advisor->areReplayRemarksLoaded()) 86 Advisor.reset(); 87 return Advisor; 88 } 89 90 std::unique_ptr<InlineAdvice> ReplayInlineAdvisor::getAdviceImpl(CallBase &CB) { 91 assert(HasReplayRemarks); 92 93 Function &Caller = *CB.getCaller(); 94 auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(Caller); 95 96 // Decision not made by replay system 97 if (!hasInlineAdvice(*CB.getFunction())) { 98 // If there's a registered original advisor, return its decision 99 if (OriginalAdvisor) 100 return OriginalAdvisor->getAdvice(CB); 101 102 // If no decision is made above, return non-decision 103 return {}; 104 } 105 106 std::string CallSiteLoc = 107 formatCallSiteLocation(CB.getDebugLoc(), ReplaySettings.ReplayFormat); 108 StringRef Callee = CB.getCalledFunction()->getName(); 109 std::string Combined = (Callee + CallSiteLoc).str(); 110 111 // Replay decision, if it has one 112 auto Iter = InlineSitesFromRemarks.find(Combined); 113 if (Iter != InlineSitesFromRemarks.end()) { 114 if (InlineSitesFromRemarks[Combined]) { 115 LLVM_DEBUG(dbgs() << "Replay Inliner: Inlined " << Callee << " @ " 116 << CallSiteLoc << "\n"); 117 return std::make_unique<DefaultInlineAdvice>( 118 this, CB, llvm::InlineCost::getAlways("previously inlined"), ORE, 119 EmitRemarks); 120 } else { 121 LLVM_DEBUG(dbgs() << "Replay Inliner: Not Inlined " << Callee << " @ " 122 << CallSiteLoc << "\n"); 123 // A negative inline is conveyed by "None" Optional<InlineCost> 124 return std::make_unique<DefaultInlineAdvice>(this, CB, None, ORE, 125 EmitRemarks); 126 } 127 } 128 129 // Fallback decisions 130 if (ReplaySettings.ReplayFallback == 131 ReplayInlinerSettings::Fallback::AlwaysInline) 132 return std::make_unique<DefaultInlineAdvice>( 133 this, CB, llvm::InlineCost::getAlways("AlwaysInline Fallback"), ORE, 134 EmitRemarks); 135 else if (ReplaySettings.ReplayFallback == 136 ReplayInlinerSettings::Fallback::NeverInline) 137 // A negative inline is conveyed by "None" Optional<InlineCost> 138 return std::make_unique<DefaultInlineAdvice>(this, CB, None, ORE, 139 EmitRemarks); 140 else { 141 assert(ReplaySettings.ReplayFallback == 142 ReplayInlinerSettings::Fallback::Original); 143 // If there's a registered original advisor, return its decision 144 if (OriginalAdvisor) 145 return OriginalAdvisor->getAdvice(CB); 146 } 147 148 // If no decision is made above, return non-decision 149 return {}; 150 } 151