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llvm-mirror/lib/Analysis/OptimizationRemarkEmitter.cpp
Evgeniy Brevnov 850ecb1d9c [BPI][NFC] Reuse post dominantor tree from analysis manager when available
Summary: Currenlty BPI unconditionally creates post dominator tree each time. While this is not incorrect we can save compile time by reusing existing post dominator tree (when it's valid) provided by analysis manager.

Reviewers: skatkov, taewookoh, yrouban

Reviewed By: skatkov

Subscribers: hiraditya, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78987
2020-04-30 11:31:03 +07:00

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4.2 KiB
C++

//===- OptimizationRemarkEmitter.cpp - Optimization Diagnostic --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Optimization diagnostic interfaces. It's packaged as an analysis pass so
// that by using this service passes become dependent on BFI as well. BFI is
// used to compute the "hotness" of the diagnostic message.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/InitializePasses.h"
using namespace llvm;
OptimizationRemarkEmitter::OptimizationRemarkEmitter(const Function *F)
: F(F), BFI(nullptr) {
if (!F->getContext().getDiagnosticsHotnessRequested())
return;
// First create a dominator tree.
DominatorTree DT;
DT.recalculate(*const_cast<Function *>(F));
// Generate LoopInfo from it.
LoopInfo LI;
LI.analyze(DT);
// Then compute BranchProbabilityInfo.
BranchProbabilityInfo BPI(*F, LI);
// Finally compute BFI.
OwnedBFI = std::make_unique<BlockFrequencyInfo>(*F, BPI, LI);
BFI = OwnedBFI.get();
}
bool OptimizationRemarkEmitter::invalidate(
Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &Inv) {
if (OwnedBFI.get()) {
OwnedBFI.reset();
BFI = nullptr;
}
// This analysis has no state and so can be trivially preserved but it needs
// a fresh view of BFI if it was constructed with one.
if (BFI && Inv.invalidate<BlockFrequencyAnalysis>(F, PA))
return true;
// Otherwise this analysis result remains valid.
return false;
}
Optional<uint64_t> OptimizationRemarkEmitter::computeHotness(const Value *V) {
if (!BFI)
return None;
return BFI->getBlockProfileCount(cast<BasicBlock>(V));
}
void OptimizationRemarkEmitter::computeHotness(
DiagnosticInfoIROptimization &OptDiag) {
const Value *V = OptDiag.getCodeRegion();
if (V)
OptDiag.setHotness(computeHotness(V));
}
void OptimizationRemarkEmitter::emit(
DiagnosticInfoOptimizationBase &OptDiagBase) {
auto &OptDiag = cast<DiagnosticInfoIROptimization>(OptDiagBase);
computeHotness(OptDiag);
// Only emit it if its hotness meets the threshold.
if (OptDiag.getHotness().getValueOr(0) <
F->getContext().getDiagnosticsHotnessThreshold()) {
return;
}
F->getContext().diagnose(OptDiag);
}
OptimizationRemarkEmitterWrapperPass::OptimizationRemarkEmitterWrapperPass()
: FunctionPass(ID) {
initializeOptimizationRemarkEmitterWrapperPassPass(
*PassRegistry::getPassRegistry());
}
bool OptimizationRemarkEmitterWrapperPass::runOnFunction(Function &Fn) {
BlockFrequencyInfo *BFI;
if (Fn.getContext().getDiagnosticsHotnessRequested())
BFI = &getAnalysis<LazyBlockFrequencyInfoPass>().getBFI();
else
BFI = nullptr;
ORE = std::make_unique<OptimizationRemarkEmitter>(&Fn, BFI);
return false;
}
void OptimizationRemarkEmitterWrapperPass::getAnalysisUsage(
AnalysisUsage &AU) const {
LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AU);
AU.setPreservesAll();
}
AnalysisKey OptimizationRemarkEmitterAnalysis::Key;
OptimizationRemarkEmitter
OptimizationRemarkEmitterAnalysis::run(Function &F,
FunctionAnalysisManager &AM) {
BlockFrequencyInfo *BFI;
if (F.getContext().getDiagnosticsHotnessRequested())
BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
else
BFI = nullptr;
return OptimizationRemarkEmitter(&F, BFI);
}
char OptimizationRemarkEmitterWrapperPass::ID = 0;
static const char ore_name[] = "Optimization Remark Emitter";
#define ORE_NAME "opt-remark-emitter"
INITIALIZE_PASS_BEGIN(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,
false, true)
INITIALIZE_PASS_DEPENDENCY(LazyBFIPass)
INITIALIZE_PASS_END(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,
false, true)