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
  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)