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      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/DiagnosticInfo.h"
     20 #include "llvm/IR/LLVMContext.h"
     21 
     22 using namespace llvm;
     23 
     24 DiagnosticInfoMIROptimization::MachineArgument::MachineArgument(
     25     StringRef MKey, const MachineInstr &MI)
     26     : Argument() {
     27   Key = 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 = 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