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//===- ProfileSummaryInfo.cpp - Global profile summary information --------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file contains a pass that provides access to the global profile summary
// information.
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ProfileSummary.h"
#include "llvm/InitializePasses.h"
#include "llvm/ProfileData/ProfileCommon.h"
#include "llvm/Support/CommandLine.h"
#include <optional>
using namespace llvm;
// Knobs for profile summary based thresholds.
namespace llvm {
extern cl::opt<int> ProfileSummaryCutoffHot;
extern cl::opt<int> ProfileSummaryCutoffCold;
extern cl::opt<unsigned> ProfileSummaryHugeWorkingSetSizeThreshold;
extern cl::opt<unsigned> ProfileSummaryLargeWorkingSetSizeThreshold;
extern cl::opt<int> ProfileSummaryHotCount;
extern cl::opt<int> ProfileSummaryColdCount;
} // namespace llvm
static cl::opt<bool> PartialProfile(
"partial-profile", cl::Hidden, cl::init(false),
cl::desc("Specify the current profile is used as a partial profile."));
cl::opt<bool> ScalePartialSampleProfileWorkingSetSize(
"scale-partial-sample-profile-working-set-size", cl::Hidden, cl::init(true),
"If true, scale the working set size of the partial sample profile "
"by the partial profile ratio to reflect the size of the program "
"being compiled."));
static cl::opt<double> PartialSampleProfileWorkingSetSizeScaleFactor(
"partial-sample-profile-working-set-size-scale-factor", cl::Hidden,
cl::desc("The scale factor used to scale the working set size of the "
"partial sample profile along with the partial profile ratio. "
"This includes the factor of the profile counter per block "
"and the factor to scale the working set size to use the same "
"shared thresholds as PGO."));
// The profile summary metadata may be attached either by the frontend or by
// any backend passes (IR level instrumentation, for example). This method
// checks if the Summary is null and if so checks if the summary metadata is now
// available in the module and parses it to get the Summary object.
void ProfileSummaryInfo::refresh() {
if (hasProfileSummary())
// First try to get context sensitive ProfileSummary.
auto *SummaryMD = M->getProfileSummary(/* IsCS */ true);
if (SummaryMD)
if (!hasProfileSummary()) {
// This will actually return PSK_Instr or PSK_Sample summary.
SummaryMD = M->getProfileSummary(/* IsCS */ false);
if (SummaryMD)
if (!hasProfileSummary())
std::optional<uint64_t> ProfileSummaryInfo::getProfileCount(
const CallBase &Call, BlockFrequencyInfo *BFI, bool AllowSynthetic) const {
assert((isa<CallInst>(Call) || isa<InvokeInst>(Call)) &&
"We can only get profile count for call/invoke instruction.");
if (hasSampleProfile()) {
// In sample PGO mode, check if there is a profile metadata on the
// instruction. If it is present, determine hotness solely based on that,
// since the sampled entry count may not be accurate. If there is no
// annotated on the instruction, return std::nullopt.
uint64_t TotalCount;
if (Call.extractProfTotalWeight(TotalCount))
return TotalCount;
return std::nullopt;
if (BFI)
return BFI->getBlockProfileCount(Call.getParent(), AllowSynthetic);
return std::nullopt;
bool ProfileSummaryInfo::isFunctionHotnessUnknown(const Function &F) const {
assert(hasPartialSampleProfile() && "Expect partial sample profile");
return !F.getEntryCount();
/// Returns true if the function's entry is a cold. If it returns false, it
/// either means it is not cold or it is unknown whether it is cold or not (for
/// example, no profile data is available).
bool ProfileSummaryInfo::isFunctionEntryCold(const Function *F) const {
if (!F)
return false;
if (F->hasFnAttribute(Attribute::Cold))
return true;
if (!hasProfileSummary())
return false;
auto FunctionCount = F->getEntryCount();
// FIXME: The heuristic used below for determining coldness is based on
// preliminary SPEC tuning for inliner. This will eventually be a
// convenience method that calls isHotCount.
return FunctionCount && isColdCount(FunctionCount->getCount());
/// Compute the hot and cold thresholds.
void ProfileSummaryInfo::computeThresholds() {
auto &DetailedSummary = Summary->getDetailedSummary();
auto &HotEntry = ProfileSummaryBuilder::getEntryForPercentile(
DetailedSummary, ProfileSummaryCutoffHot);
HotCountThreshold =
ColdCountThreshold =
assert(ColdCountThreshold <= HotCountThreshold &&
"Cold count threshold cannot exceed hot count threshold!");
if (!hasPartialSampleProfile() || !ScalePartialSampleProfileWorkingSetSize) {
HasHugeWorkingSetSize =
HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
HasLargeWorkingSetSize =
HotEntry.NumCounts > ProfileSummaryLargeWorkingSetSizeThreshold;
} else {
// Scale the working set size of the partial sample profile to reflect the
// size of the program being compiled.
double PartialProfileRatio = Summary->getPartialProfileRatio();
uint64_t ScaledHotEntryNumCounts =
static_cast<uint64_t>(HotEntry.NumCounts * PartialProfileRatio *
HasHugeWorkingSetSize =
ScaledHotEntryNumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
HasLargeWorkingSetSize =
ScaledHotEntryNumCounts > ProfileSummaryLargeWorkingSetSizeThreshold;
ProfileSummaryInfo::computeThreshold(int PercentileCutoff) const {
if (!hasProfileSummary())
return std::nullopt;
auto iter = ThresholdCache.find(PercentileCutoff);
if (iter != ThresholdCache.end()) {
return iter->second;
auto &DetailedSummary = Summary->getDetailedSummary();
auto &Entry = ProfileSummaryBuilder::getEntryForPercentile(DetailedSummary,
uint64_t CountThreshold = Entry.MinCount;
ThresholdCache[PercentileCutoff] = CountThreshold;
return CountThreshold;
bool ProfileSummaryInfo::hasHugeWorkingSetSize() const {
return HasHugeWorkingSetSize && *HasHugeWorkingSetSize;
bool ProfileSummaryInfo::hasLargeWorkingSetSize() const {
return HasLargeWorkingSetSize && *HasLargeWorkingSetSize;
bool ProfileSummaryInfo::isHotCount(uint64_t C) const {
return HotCountThreshold && C >= *HotCountThreshold;
bool ProfileSummaryInfo::isColdCount(uint64_t C) const {
return ColdCountThreshold && C <= *ColdCountThreshold;
template <bool isHot>
bool ProfileSummaryInfo::isHotOrColdCountNthPercentile(int PercentileCutoff,
uint64_t C) const {
auto CountThreshold = computeThreshold(PercentileCutoff);
if (isHot)
return CountThreshold && C >= *CountThreshold;
return CountThreshold && C <= *CountThreshold;
bool ProfileSummaryInfo::isHotCountNthPercentile(int PercentileCutoff,
uint64_t C) const {
return isHotOrColdCountNthPercentile<true>(PercentileCutoff, C);
bool ProfileSummaryInfo::isColdCountNthPercentile(int PercentileCutoff,
uint64_t C) const {
return isHotOrColdCountNthPercentile<false>(PercentileCutoff, C);
uint64_t ProfileSummaryInfo::getOrCompHotCountThreshold() const {
return HotCountThreshold.value_or(UINT64_MAX);
uint64_t ProfileSummaryInfo::getOrCompColdCountThreshold() const {
return ColdCountThreshold.value_or(0);
bool ProfileSummaryInfo::isHotCallSite(const CallBase &CB,
BlockFrequencyInfo *BFI) const {
auto C = getProfileCount(CB, BFI);
return C && isHotCount(*C);
bool ProfileSummaryInfo::isColdCallSite(const CallBase &CB,
BlockFrequencyInfo *BFI) const {
auto C = getProfileCount(CB, BFI);
if (C)
return isColdCount(*C);
// In SamplePGO, if the caller has been sampled, and there is no profile
// annotated on the callsite, we consider the callsite as cold.
return hasSampleProfile() && CB.getCaller()->hasProfileData();
bool ProfileSummaryInfo::hasPartialSampleProfile() const {
return hasProfileSummary() &&
Summary->getKind() == ProfileSummary::PSK_Sample &&
(PartialProfile || Summary->isPartialProfile());
INITIALIZE_PASS(ProfileSummaryInfoWrapperPass, "profile-summary-info",
"Profile summary info", false, true)
: ImmutablePass(ID) {
bool ProfileSummaryInfoWrapperPass::doInitialization(Module &M) {
PSI.reset(new ProfileSummaryInfo(M));
return false;
bool ProfileSummaryInfoWrapperPass::doFinalization(Module &M) {
return false;
AnalysisKey ProfileSummaryAnalysis::Key;
ProfileSummaryInfo ProfileSummaryAnalysis::run(Module &M,
ModuleAnalysisManager &) {
return ProfileSummaryInfo(M);
PreservedAnalyses ProfileSummaryPrinterPass::run(Module &M,
ModuleAnalysisManager &AM) {
ProfileSummaryInfo &PSI = AM.getResult<ProfileSummaryAnalysis>(M);
OS << "Functions in " << M.getName() << " with hot/cold annotations: \n";
for (auto &F : M) {
OS << F.getName();
if (PSI.isFunctionEntryHot(&F))
OS << " :hot entry ";
else if (PSI.isFunctionEntryCold(&F))
OS << " :cold entry ";
OS << "\n";
return PreservedAnalyses::all();
char ProfileSummaryInfoWrapperPass::ID = 0;