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//===- 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/Analysis/ProfileSummaryInfo.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, nullptr, &DT, nullptr);
// 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;
auto &Context = Fn.getContext();
if (Context.getDiagnosticsHotnessRequested()) {
BFI = &getAnalysis<LazyBlockFrequencyInfoPass>().getBFI();
// Get hotness threshold from PSI. This should only happen once.
if (Context.isDiagnosticsHotnessThresholdSetFromPSI()) {
if (ProfileSummaryInfo *PSI =
&getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI())
Context.setDiagnosticsHotnessThreshold(
PSI->getOrCompHotCountThreshold());
}
} else
BFI = nullptr;
ORE = std::make_unique<OptimizationRemarkEmitter>(&Fn, BFI);
return false;
}
void OptimizationRemarkEmitterWrapperPass::getAnalysisUsage(
AnalysisUsage &AU) const {
LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AU);
AU.addRequired<ProfileSummaryInfoWrapperPass>();
AU.setPreservesAll();
}
AnalysisKey OptimizationRemarkEmitterAnalysis::Key;
OptimizationRemarkEmitter
OptimizationRemarkEmitterAnalysis::run(Function &F,
FunctionAnalysisManager &AM) {
BlockFrequencyInfo *BFI;
auto &Context = F.getContext();
if (Context.getDiagnosticsHotnessRequested()) {
BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
// Get hotness threshold from PSI. This should only happen once.
if (Context.isDiagnosticsHotnessThresholdSetFromPSI()) {
auto &MAMProxy = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
if (ProfileSummaryInfo *PSI =
MAMProxy.getCachedResult<ProfileSummaryAnalysis>(*F.getParent()))
Context.setDiagnosticsHotnessThreshold(
PSI->getOrCompHotCountThreshold());
}
} 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_DEPENDENCY(ProfileSummaryInfoWrapperPass)
INITIALIZE_PASS_END(OptimizationRemarkEmitterWrapperPass, ORE_NAME, ore_name,
false, true)
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