1 //===- OptimizationRemarkEmitter.cpp - Optimization Diagnostic --*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
9 // Optimization diagnostic interfaces. It's packaged as an analysis pass so
10 // that by using this service passes become dependent on BFI as well. BFI is
11 // used to compute the "hotness" of the diagnostic message.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
15 #include "llvm/Analysis/BranchProbabilityInfo.h"
16 #include "llvm/Analysis/LazyBlockFrequencyInfo.h"
17 #include "llvm/Analysis/LoopInfo.h"
18 #include "llvm/IR/DiagnosticInfo.h"
19 #include "llvm/IR/Dominators.h"
20 #include "llvm/IR/LLVMContext.h"
24 OptimizationRemarkEmitter::OptimizationRemarkEmitter(const Function *F)
25 : F(F), BFI(nullptr) {
26 if (!F->getContext().getDiagnosticsHotnessRequested())
29 // First create a dominator tree.
31 DT.recalculate(*const_cast<Function *>(F));
33 // Generate LoopInfo from it.
37 // Then compute BranchProbabilityInfo.
38 BranchProbabilityInfo BPI;
39 BPI.calculate(*F, LI);
41 // Finally compute BFI.
42 OwnedBFI = llvm::make_unique<BlockFrequencyInfo>(*F, BPI, LI);
46 bool OptimizationRemarkEmitter::invalidate(
47 Function &F, const PreservedAnalyses &PA,
48 FunctionAnalysisManager::Invalidator &Inv) {
49 // This analysis has no state and so can be trivially preserved but it needs
50 // a fresh view of BFI if it was constructed with one.
51 if (BFI && Inv.invalidate<BlockFrequencyAnalysis>(F, PA))
54 // Otherwise this analysis result remains valid.
58 Optional<uint64_t> OptimizationRemarkEmitter::computeHotness(const Value *V) {
62 return BFI->getBlockProfileCount(cast<BasicBlock>(V));
65 void OptimizationRemarkEmitter::computeHotness(
66 DiagnosticInfoIROptimization &OptDiag) {
67 const Value *V = OptDiag.getCodeRegion();
69 OptDiag.setHotness(computeHotness(V));
72 void OptimizationRemarkEmitter::emit(
73 DiagnosticInfoOptimizationBase &OptDiagBase) {
74 auto &OptDiag = cast<DiagnosticInfoIROptimization>(OptDiagBase);
75 computeHotness(OptDiag);
77 // Only emit it if its hotness meets the threshold.
78 if (OptDiag.getHotness().getValueOr(0) <
79 F->getContext().getDiagnosticsHotnessThreshold()) {
83 F->getContext().diagnose(OptDiag);
86 OptimizationRemarkEmitterWrapperPass::OptimizationRemarkEmitterWrapperPass()
88 initializeOptimizationRemarkEmitterWrapperPassPass(
89 *PassRegistry::getPassRegistry());
92 bool OptimizationRemarkEmitterWrapperPass::runOnFunction(Function &Fn) {
93 BlockFrequencyInfo *BFI;
95 if (Fn.getContext().getDiagnosticsHotnessRequested())
96 BFI = &getAnalysis<LazyBlockFrequencyInfoPass>().getBFI();
100 ORE = llvm::make_unique<OptimizationRemarkEmitter>(&Fn, BFI);
104 void OptimizationRemarkEmitterWrapperPass::getAnalysisUsage(
105 AnalysisUsage &AU) const {
106 LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AU);
107 AU.setPreservesAll();
110 AnalysisKey OptimizationRemarkEmitterAnalysis::Key;
112 OptimizationRemarkEmitter
113 OptimizationRemarkEmitterAnalysis::run(Function &F,
114 FunctionAnalysisManager &AM) {
115 BlockFrequencyInfo *BFI;
117 if (F.getContext().getDiagnosticsHotnessRequested())
118 BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
122 return OptimizationRemarkEmitter(&F, BFI);
125 char OptimizationRemarkEmitterWrapperPass::ID = 0;
126 static const char ore_name[] = "Optimization Remark Emitter";
127 #define ORE_NAME "opt-remark-emitter"
129 INITIALIZE_PASS_BEGIN(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,
131 INITIALIZE_PASS_DEPENDENCY(LazyBFIPass)
132 INITIALIZE_PASS_END(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,