1 ///===- MachineOptimizationRemarkEmitter.cpp - Opt Diagnostic -*- C++ -*---===//
2 ///
3 ///                     The LLVM Compiler Infrastructure
4 ///
5 /// This file is distributed under the University of Illinois Open Source
6 /// License. See LICENSE.TXT for details.
7 ///
8 ///===---------------------------------------------------------------------===//
9 /// \file
10 /// Optimization diagnostic interfaces for machine passes.  It's packaged as an
11 /// analysis pass so that by using this service passes become dependent on MBFI
12 /// as well.  MBFI is used to compute the "hotness" of the diagnostic message.
13 ///
14 ///===---------------------------------------------------------------------===//
15 
16 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
17 #include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
18 #include "llvm/CodeGen/MachineInstr.h"
19 #include "llvm/IR/DiagnosticInfo.h"
20 #include "llvm/IR/LLVMContext.h"
21 
22 using namespace llvm;
23 
24 DiagnosticInfoMIROptimization::MachineArgument::MachineArgument(
25     StringRef MKey, const MachineInstr &MI)
26     : Argument() {
27   Key = MKey;
28 
29   raw_string_ostream OS(Val);
30   MI.print(OS, /*SkipOpers=*/false, /*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().getValueOr(0) <
57       Ctx.getDiagnosticsHotnessThreshold()) {
58     return;
59   }
60 
61   Ctx.diagnose(OptDiag);
62 }
63 
64 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
65     : MachineFunctionPass(ID) {
66   initializeMachineOptimizationRemarkEmitterPassPass(
67       *PassRegistry::getPassRegistry());
68 }
69 
70 bool MachineOptimizationRemarkEmitterPass::runOnMachineFunction(
71     MachineFunction &MF) {
72   MachineBlockFrequencyInfo *MBFI;
73 
74   if (MF.getFunction().getContext().getDiagnosticsHotnessRequested())
75     MBFI = &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
76   else
77     MBFI = nullptr;
78 
79   ORE = llvm::make_unique<MachineOptimizationRemarkEmitter>(MF, MBFI);
80   return false;
81 }
82 
83 void MachineOptimizationRemarkEmitterPass::getAnalysisUsage(
84     AnalysisUsage &AU) const {
85   AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
86   AU.setPreservesAll();
87   MachineFunctionPass::getAnalysisUsage(AU);
88 }
89 
90 char MachineOptimizationRemarkEmitterPass::ID = 0;
91 static const char ore_name[] = "Machine Optimization Remark Emitter";
92 #define ORE_NAME "machine-opt-remark-emitter"
93 
94 INITIALIZE_PASS_BEGIN(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
95                       false, true)
96 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
97 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
98                     false, true)
99