llvm/lib/CodeGen/MachineOptimizationRemarkEmitter.cpp

   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 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>
  43 MachineOptimizationRemarkEmitter::computeHotness(const MachineBasicBlock &MBB) {
  44   if (!MBFI)
  45     return std::nullopt;
  46
  47   return MBFI->getBlockProfileCount(&MBB);
  48 }
  49
  50 void MachineOptimizationRemarkEmitter::computeHotness(
  51     DiagnosticInfoMIROptimization &Remark) {
  52   const MachineBasicBlock *MBB = Remark.getBlock();
  53   if (MBB)
  54     Remark.setHotness(computeHotness(*MBB));
  55 }
  56
  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
  71 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
  72     : MachineFunctionPass(ID) {
  73   initializeMachineOptimizationRemarkEmitterPassPass(
  74       *PassRegistry::getPassRegistry());
  75 }
  76
  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
  90 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
 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)