1 ///===- MachineOptimizationRemarkEmitter.cpp - Opt Diagnostic -*- C++ -*---===//
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 /// \file
9 /// Optimization diagnostic interfaces for machine passes. It's packaged as an
10 /// analysis pass so that by using this service passes become dependent on MBFI
11 /// as well. MBFI is used to compute the "hotness" of the diagnostic message.
12 ///
13 ///===---------------------------------------------------------------------===//
14
15 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
16 #include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
17 #include "llvm/CodeGen/MachineInstr.h"
18 #include "llvm/IR/DiagnosticInfo.h"
19 #include "llvm/IR/LLVMContext.h"
20 #include "llvm/InitializePasses.h"
21 #include <optional>
22
23 using namespace llvm;
24
MachineArgument(StringRef MKey,const MachineInstr & MI)25 DiagnosticInfoMIROptimization::MachineArgument::MachineArgument(
26 StringRef MKey, const MachineInstr &MI) {
27 Key = std::string(MKey);
28
29 raw_string_ostream OS(Val);
30 MI.print(OS, /*IsStandalone=*/true, /*SkipOpers=*/false,
31 /*SkipDebugLoc=*/true);
32 }
33
invalidate(MachineFunction & MF,const PreservedAnalyses & PA,MachineFunctionAnalysisManager::Invalidator & Inv)34 bool MachineOptimizationRemarkEmitter::invalidate(
35 MachineFunction &MF, const PreservedAnalyses &PA,
36 MachineFunctionAnalysisManager::Invalidator &Inv) {
37 // This analysis has no state and so can be trivially preserved but it needs
38 // a fresh view of BFI if it was constructed with one.
39 return MBFI && Inv.invalidate<MachineBlockFrequencyAnalysis>(MF, PA);
40 }
41
42 std::optional<uint64_t>
computeHotness(const MachineBasicBlock & MBB)43 MachineOptimizationRemarkEmitter::computeHotness(const MachineBasicBlock &MBB) {
44 if (!MBFI)
45 return std::nullopt;
46
47 return MBFI->getBlockProfileCount(&MBB);
48 }
49
computeHotness(DiagnosticInfoMIROptimization & Remark)50 void MachineOptimizationRemarkEmitter::computeHotness(
51 DiagnosticInfoMIROptimization &Remark) {
52 const MachineBasicBlock *MBB = Remark.getBlock();
53 if (MBB)
54 Remark.setHotness(computeHotness(*MBB));
55 }
56
emit(DiagnosticInfoOptimizationBase & OptDiagCommon)57 void MachineOptimizationRemarkEmitter::emit(
58 DiagnosticInfoOptimizationBase &OptDiagCommon) {
59 auto &OptDiag = cast<DiagnosticInfoMIROptimization>(OptDiagCommon);
60 computeHotness(OptDiag);
61
62 LLVMContext &Ctx = MF.getFunction().getContext();
63
64 // Only emit it if its hotness meets the threshold.
65 if (OptDiag.getHotness().value_or(0) < Ctx.getDiagnosticsHotnessThreshold())
66 return;
67
68 Ctx.diagnose(OptDiag);
69 }
70
MachineOptimizationRemarkEmitterPass()71 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
72 : MachineFunctionPass(ID) {
73 initializeMachineOptimizationRemarkEmitterPassPass(
74 *PassRegistry::getPassRegistry());
75 }
76
runOnMachineFunction(MachineFunction & MF)77 bool MachineOptimizationRemarkEmitterPass::runOnMachineFunction(
78 MachineFunction &MF) {
79 MachineBlockFrequencyInfo *MBFI;
80
81 if (MF.getFunction().getContext().getDiagnosticsHotnessRequested())
82 MBFI = &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
83 else
84 MBFI = nullptr;
85
86 ORE = std::make_unique<MachineOptimizationRemarkEmitter>(MF, MBFI);
87 return false;
88 }
89
getAnalysisUsage(AnalysisUsage & AU) const90 void MachineOptimizationRemarkEmitterPass::getAnalysisUsage(
91 AnalysisUsage &AU) const {
92 AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
93 AU.setPreservesAll();
94 MachineFunctionPass::getAnalysisUsage(AU);
95 }
96
97 AnalysisKey MachineOptimizationRemarkEmitterAnalysis::Key;
98
99 MachineOptimizationRemarkEmitterAnalysis::Result
run(MachineFunction & MF,MachineFunctionAnalysisManager & MFAM)100 MachineOptimizationRemarkEmitterAnalysis::run(
101 MachineFunction &MF, MachineFunctionAnalysisManager &MFAM) {
102 MachineBlockFrequencyInfo *MBFI =
103 MF.getFunction().getContext().getDiagnosticsHotnessRequested()
104 ? &MFAM.getResult<MachineBlockFrequencyAnalysis>(MF)
105 : nullptr;
106 return Result(MF, MBFI);
107 }
108
109 char MachineOptimizationRemarkEmitterPass::ID = 0;
110 static const char ore_name[] = "Machine Optimization Remark Emitter";
111 #define ORE_NAME "machine-opt-remark-emitter"
112
113 INITIALIZE_PASS_BEGIN(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
114 true, true)
115 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
116 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
117 true, true)
118