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 21 using namespace llvm; 22 23 #define DEBUG_TYPE "inline-replay" 24 25 ReplayInlineAdvisor::ReplayInlineAdvisor( 26 Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context, 27 std::unique_ptr<InlineAdvisor> OriginalAdvisor, StringRef RemarksFile, 28 bool EmitRemarks) 29 : InlineAdvisor(M, FAM), OriginalAdvisor(std::move(OriginalAdvisor)), 30 HasReplayRemarks(false), EmitRemarks(EmitRemarks) { 31 auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(RemarksFile); 32 std::error_code EC = BufferOrErr.getError(); 33 if (EC) { 34 Context.emitError("Could not open remarks file: " + EC.message()); 35 return; 36 } 37 38 // Example for inline remarks to parse: 39 // main:3:1.1: _Z3subii inlined into main at callsite sum:1 @ main:3:1.1 40 // We use the callsite string after `at callsite` to replay inlining. 41 line_iterator LineIt(*BufferOrErr.get(), /*SkipBlanks=*/true); 42 for (; !LineIt.is_at_eof(); ++LineIt) { 43 StringRef Line = *LineIt; 44 auto Pair = Line.split(" at callsite "); 45 46 auto Callee = Pair.first.split(" inlined into").first.rsplit(": ").second; 47 48 auto CallSite = Pair.second.split(";").first; 49 50 if (Callee.empty() || CallSite.empty()) 51 continue; 52 53 std::string Combined = (Callee + CallSite).str(); 54 InlineSitesFromRemarks.insert(Combined); 55 } 56 57 HasReplayRemarks = true; 58 } 59 60 std::unique_ptr<InlineAdvice> ReplayInlineAdvisor::getAdviceImpl(CallBase &CB) { 61 assert(HasReplayRemarks); 62 63 Function &Caller = *CB.getCaller(); 64 auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(Caller); 65 66 if (InlineSitesFromRemarks.empty()) 67 return std::make_unique<DefaultInlineAdvice>(this, CB, None, ORE, 68 EmitRemarks); 69 70 std::string CallSiteLoc = getCallSiteLocation(CB.getDebugLoc()); 71 StringRef Callee = CB.getCalledFunction()->getName(); 72 std::string Combined = (Callee + CallSiteLoc).str(); 73 auto Iter = InlineSitesFromRemarks.find(Combined); 74 75 Optional<InlineCost> InlineRecommended = None; 76 if (Iter != InlineSitesFromRemarks.end()) { 77 InlineRecommended = llvm::InlineCost::getAlways("found in replay"); 78 } 79 80 return std::make_unique<DefaultInlineAdvice>(this, CB, InlineRecommended, ORE, 81 EmitRemarks); 82 } 83