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
ReplayInlineAdvisor(Module & M,FunctionAnalysisManager & FAM,LLVMContext & Context,std::unique_ptr<InlineAdvisor> OriginalAdvisor,StringRef RemarksFile,bool EmitRemarks)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
getAdviceImpl(CallBase & CB)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