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/DebugInfo.h"
20 #include "llvm/IR/DiagnosticInfo.h"
21 #include "llvm/IR/LLVMContext.h"
22 
23 using namespace llvm;
24 
25 DiagnosticInfoMIROptimization::MachineArgument::MachineArgument(
26     StringRef MKey, const MachineInstr &MI)
27     : Argument() {
28   Key = MKey;
29 
30   raw_string_ostream OS(Val);
31   MI.print(OS, /*SkipOpers=*/false, /*SkipDebugLoc=*/true);
32 }
33 
34 Optional<uint64_t>
35 MachineOptimizationRemarkEmitter::computeHotness(const MachineBasicBlock &MBB) {
36   if (!MBFI)
37     return None;
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().getValueOr(0) <
58       Ctx.getDiagnosticsHotnessThreshold()) {
59     return;
60   }
61 
62   Ctx.diagnose(OptDiag);
63 }
64 
65 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
66     : MachineFunctionPass(ID) {
67   initializeMachineOptimizationRemarkEmitterPassPass(
68       *PassRegistry::getPassRegistry());
69 }
70 
71 bool MachineOptimizationRemarkEmitterPass::runOnMachineFunction(
72     MachineFunction &MF) {
73   MachineBlockFrequencyInfo *MBFI;
74 
75   if (MF.getFunction()->getContext().getDiagnosticsHotnessRequested())
76     MBFI = &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
77   else
78     MBFI = nullptr;
79 
80   ORE = llvm::make_unique<MachineOptimizationRemarkEmitter>(MF, MBFI);
81   return false;
82 }
83 
84 void MachineOptimizationRemarkEmitterPass::getAnalysisUsage(
85     AnalysisUsage &AU) const {
86   AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
87   AU.setPreservesAll();
88   MachineFunctionPass::getAnalysisUsage(AU);
89 }
90 
91 char MachineOptimizationRemarkEmitterPass::ID = 0;
92 static const char ore_name[] = "Machine Optimization Remark Emitter";
93 #define ORE_NAME "machine-opt-remark-emitter"
94 
95 INITIALIZE_PASS_BEGIN(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
96                       false, true)
97 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
98 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
99                     false, true)
100