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 decision based
10 // on previous inline remarks from optimization remark log.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Analysis/ReplayInlineAdvisor.h"
15 #include "llvm/IR/DebugInfoMetadata.h"
16 #include "llvm/IR/Instructions.h"
17 #include "llvm/Support/LineIterator.h"
18 
19 using namespace llvm;
20 
21 #define DEBUG_TYPE "inline-replay"
22 
23 ReplayInlineAdvisor::ReplayInlineAdvisor(FunctionAnalysisManager &FAM,
24                                          LLVMContext &Context,
25                                          StringRef RemarksFile)
26     : InlineAdvisor(FAM), HasReplayRemarks(false) {
27   auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(RemarksFile);
28   std::error_code EC = BufferOrErr.getError();
29   if (EC) {
30     Context.emitError("Could not open remarks file: " + EC.message());
31     return;
32   }
33 
34   // Example for inline remarks to parse:
35   //   _Z3subii inlined into main [details] at callsite sum:1 @ main:3.1
36   // We use the callsite string after `at callsite` to replay inlining.
37   line_iterator LineIt(*BufferOrErr.get(), /*SkipBlanks=*/true);
38   for (; !LineIt.is_at_eof(); ++LineIt) {
39     StringRef Line = *LineIt;
40     auto Pair = Line.split(" at callsite ");
41     if (Pair.second.empty())
42       continue;
43     InlineSitesFromRemarks.insert(Pair.second);
44   }
45   HasReplayRemarks = true;
46 }
47 
48 std::unique_ptr<InlineAdvice> ReplayInlineAdvisor::getAdvice(CallBase &CB) {
49   assert(HasReplayRemarks);
50 
51   Function &Caller = *CB.getCaller();
52   auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(Caller);
53 
54   if (InlineSitesFromRemarks.empty())
55     return std::make_unique<InlineAdvice>(this, CB, ORE, false);
56 
57   std::string CallSiteLoc = getCallSiteLocation(CB.getDebugLoc());
58   bool InlineRecommended = InlineSitesFromRemarks.count(CallSiteLoc) > 0;
59   return std::make_unique<InlineAdvice>(this, CB, ORE, InlineRecommended);
60 }
61