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     : Argument() {
  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 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 = std::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                       true, true)
  97 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
  98 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
  99                     true, true)