154 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements ReplayInlineAdvisor that replays inline decisions based10// on previous inline remarks from optimization remark log. This is a best11// effort approach useful for testing compiler/source changes while holding12// inlining steady.13//14//===----------------------------------------------------------------------===//15 16#include "llvm/Analysis/ReplayInlineAdvisor.h"17#include "llvm/Analysis/OptimizationRemarkEmitter.h"18#include "llvm/Support/LineIterator.h"19#include "llvm/Support/MemoryBuffer.h"20#include <memory>21 22using namespace llvm;23 24#define DEBUG_TYPE "replay-inline"25 26ReplayInlineAdvisor::ReplayInlineAdvisor(27 Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context,28 std::unique_ptr<InlineAdvisor> OriginalAdvisor,29 const ReplayInlinerSettings &ReplaySettings, bool EmitRemarks,30 InlineContext IC)31 : InlineAdvisor(M, FAM, IC), OriginalAdvisor(std::move(OriginalAdvisor)),32 ReplaySettings(ReplaySettings), 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 79std::unique_ptr<InlineAdvisor>80llvm::getReplayInlineAdvisor(Module &M, FunctionAnalysisManager &FAM,81 LLVMContext &Context,82 std::unique_ptr<InlineAdvisor> OriginalAdvisor,83 const ReplayInlinerSettings &ReplaySettings,84 bool EmitRemarks, InlineContext IC) {85 auto Advisor = std::make_unique<ReplayInlineAdvisor>(86 M, FAM, Context, std::move(OriginalAdvisor), ReplaySettings, EmitRemarks,87 IC);88 if (!Advisor->areReplayRemarksLoaded())89 Advisor.reset();90 return Advisor;91}92 93std::unique_ptr<InlineAdvice> ReplayInlineAdvisor::getAdviceImpl(CallBase &CB) {94 assert(HasReplayRemarks);95 96 Function &Caller = *CB.getCaller();97 auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(Caller);98 99 // Decision not made by replay system100 if (!hasInlineAdvice(*CB.getFunction())) {101 // If there's a registered original advisor, return its decision102 if (OriginalAdvisor)103 return OriginalAdvisor->getAdvice(CB);104 105 // If no decision is made above, return non-decision106 return {};107 }108 109 std::string CallSiteLoc =110 formatCallSiteLocation(CB.getDebugLoc(), ReplaySettings.ReplayFormat);111 StringRef Callee = CB.getCalledFunction()->getName();112 std::string Combined = (Callee + CallSiteLoc).str();113 114 // Replay decision, if it has one115 auto Iter = InlineSitesFromRemarks.find(Combined);116 if (Iter != InlineSitesFromRemarks.end()) {117 if (Iter->second) {118 LLVM_DEBUG(dbgs() << "Replay Inliner: Inlined " << Callee << " @ "119 << CallSiteLoc << "\n");120 return std::make_unique<DefaultInlineAdvice>(121 this, CB, llvm::InlineCost::getAlways("previously inlined"), ORE,122 EmitRemarks);123 } else {124 LLVM_DEBUG(dbgs() << "Replay Inliner: Not Inlined " << Callee << " @ "125 << CallSiteLoc << "\n");126 // A negative inline is conveyed by "None" std::optional<InlineCost>127 return std::make_unique<DefaultInlineAdvice>(this, CB, std::nullopt, ORE,128 EmitRemarks);129 }130 }131 132 // Fallback decisions133 if (ReplaySettings.ReplayFallback ==134 ReplayInlinerSettings::Fallback::AlwaysInline)135 return std::make_unique<DefaultInlineAdvice>(136 this, CB, llvm::InlineCost::getAlways("AlwaysInline Fallback"), ORE,137 EmitRemarks);138 else if (ReplaySettings.ReplayFallback ==139 ReplayInlinerSettings::Fallback::NeverInline)140 // A negative inline is conveyed by "None" std::optional<InlineCost>141 return std::make_unique<DefaultInlineAdvice>(this, CB, std::nullopt, ORE,142 EmitRemarks);143 else {144 assert(ReplaySettings.ReplayFallback ==145 ReplayInlinerSettings::Fallback::Original);146 // If there's a registered original advisor, return its decision147 if (OriginalAdvisor)148 return OriginalAdvisor->getAdvice(CB);149 }150 151 // If no decision is made above, return non-decision152 return {};153}154