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 
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 
34 std::optional<uint64_t>
35 MachineOptimizationRemarkEmitter::computeHotness(const MachineBasicBlock &MBB) {
36   if (!MBFI)
37     return std::nullopt;
38 
39   return MBFI->getBlockProfileCount(&MBB);
40 }
41 
42 void MachineOptimizationRemarkEmitter::computeHotness(
43     DiagnosticInfoMIROptimization &Remark) {
44   const MachineBasicBlock *MBB = Remark.getBlock();
45   if (MBB)
46     Remark.setHotness(computeHotness(*MBB));
47 }
48 
49 void MachineOptimizationRemarkEmitter::emit(
50     DiagnosticInfoOptimizationBase &OptDiagCommon) {
51   auto &OptDiag = cast<DiagnosticInfoMIROptimization>(OptDiagCommon);
52   computeHotness(OptDiag);
53 
54   LLVMContext &Ctx = MF.getFunction().getContext();
55 
56   // Only emit it if its hotness meets the threshold.
57   if (OptDiag.getHotness().value_or(0) < Ctx.getDiagnosticsHotnessThreshold())
58     return;
59 
60   Ctx.diagnose(OptDiag);
61 }
62 
63 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
64     : MachineFunctionPass(ID) {
65   initializeMachineOptimizationRemarkEmitterPassPass(
66       *PassRegistry::getPassRegistry());
67 }
68 
69 bool MachineOptimizationRemarkEmitterPass::runOnMachineFunction(
70     MachineFunction &MF) {
71   MachineBlockFrequencyInfo *MBFI;
72 
73   if (MF.getFunction().getContext().getDiagnosticsHotnessRequested())
74     MBFI = &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
75   else
76     MBFI = nullptr;
77 
78   ORE = std::make_unique<MachineOptimizationRemarkEmitter>(MF, MBFI);
79   return false;
80 }
81 
82 void MachineOptimizationRemarkEmitterPass::getAnalysisUsage(
83     AnalysisUsage &AU) const {
84   AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
85   AU.setPreservesAll();
86   MachineFunctionPass::getAnalysisUsage(AU);
87 }
88 
89 char MachineOptimizationRemarkEmitterPass::ID = 0;
90 static const char ore_name[] = "Machine Optimization Remark Emitter";
91 #define ORE_NAME "machine-opt-remark-emitter"
92 
93 INITIALIZE_PASS_BEGIN(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
94                       true, true)
95 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
96 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
97                     true, true)
98