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 std::optional<uint64_t>
  35 MachineOptimizationRemarkEmitter::computeHotness(const MachineBasicBlock &MBB) {
  36   if (!MBFI)
  37     return std::nullopt;
  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().value_or(0) < Ctx.getDiagnosticsHotnessThreshold())
  58     return;
  59
  60   Ctx.diagnose(OptDiag);
  61 }
  62
  63 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
  64     : MachineFunctionPass(ID) {
  65   initializeMachineOptimizationRemarkEmitterPassPass(
  66       *PassRegistry::getPassRegistry());
  67 }
  68
  69 bool MachineOptimizationRemarkEmitterPass::runOnMachineFunction(
  70     MachineFunction &MF) {
  71   MachineBlockFrequencyInfo *MBFI;
  72
  73   if (MF.getFunction().getContext().getDiagnosticsHotnessRequested())
  74     MBFI = &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
  75   else
  76     MBFI = nullptr;
  77
  78   ORE = std::make_unique<MachineOptimizationRemarkEmitter>(MF, MBFI);
  79   return false;
  80 }
  81
  82 void MachineOptimizationRemarkEmitterPass::getAnalysisUsage(
  83     AnalysisUsage &AU) const {
  84   AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
  85   AU.setPreservesAll();
  86   MachineFunctionPass::getAnalysisUsage(AU);
  87 }
  88
  89 char MachineOptimizationRemarkEmitterPass::ID = 0;
  90 static const char ore_name[] = "Machine Optimization Remark Emitter";
  91 #define ORE_NAME "machine-opt-remark-emitter"
  92
  93 INITIALIZE_PASS_BEGIN(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
  94                       true, true)
  95 INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass)
  96 INITIALIZE_PASS_END(MachineOptimizationRemarkEmitterPass, ORE_NAME, ore_name,
  97                     true, true)