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 
22 using namespace llvm;
23 
24 DiagnosticInfoMIROptimization::MachineArgument::MachineArgument(
25     StringRef MKey, const MachineInstr &MI) {
26   Key = std::string(MKey);
27 
28   raw_string_ostream OS(Val);
29   MI.print(OS, /*IsStandalone=*/true, /*SkipOpers=*/false,
30            /*SkipDebugLoc=*/true);
31 }
32 
33 Optional<uint64_t>
34 MachineOptimizationRemarkEmitter::computeHotness(const MachineBasicBlock &MBB) {
35   if (!MBFI)
36     return None;
37 
38   return MBFI->getBlockProfileCount(&MBB);
39 }
40 
41 void MachineOptimizationRemarkEmitter::computeHotness(
42     DiagnosticInfoMIROptimization &Remark) {
43   const MachineBasicBlock *MBB = Remark.getBlock();
44   if (MBB)
45     Remark.setHotness(computeHotness(*MBB));
46 }
47 
48 void MachineOptimizationRemarkEmitter::emit(
49     DiagnosticInfoOptimizationBase &OptDiagCommon) {
50   auto &OptDiag = cast<DiagnosticInfoMIROptimization>(OptDiagCommon);
51   computeHotness(OptDiag);
52 
53   LLVMContext &Ctx = MF.getFunction().getContext();
54 
55   // Only emit it if its hotness meets the threshold.
56   if (OptDiag.getHotness().value_or(0) < Ctx.getDiagnosticsHotnessThreshold())
57     return;
58 
59   Ctx.diagnose(OptDiag);
60 }
61 
62 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
63     : MachineFunctionPass(ID) {
64   initializeMachineOptimizationRemarkEmitterPassPass(
65       *PassRegistry::getPassRegistry());
66 }
67 
68 bool MachineOptimizationRemarkEmitterPass::runOnMachineFunction(
69     MachineFunction &MF) {
70   MachineBlockFrequencyInfo *MBFI;
71 
72   if (MF.getFunction().getContext().getDiagnosticsHotnessRequested())
73     MBFI = &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
74   else
75     MBFI = nullptr;
76 
77   ORE = std::make_unique<MachineOptimizationRemarkEmitter>(MF, MBFI);
78   return false;
79 }
80 
81 void MachineOptimizationRemarkEmitterPass::getAnalysisUsage(
82     AnalysisUsage &AU) const {
83   AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
84   AU.setPreservesAll();
85   MachineFunctionPass::getAnalysisUsage(AU);
86 }
87 
88 char MachineOptimizationRemarkEmitterPass::ID = 0;
89 static const char ore_name[] = "Machine Optimization Remark Emitter";
90 #define ORE_NAME "machine-opt-remark-emitter"
91 
92 INITIALIZE_PASS_BEGIN(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
93                       true, true)
94 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
95 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
96                     true, true)
97