1 //===- ProfileSummaryInfo.cpp - Global profile summary information --------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains a pass that provides access to the global profile summary
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Analysis/ProfileSummaryInfo.h"
16 #include "llvm/Analysis/BlockFrequencyInfo.h"
17 #include "llvm/IR/BasicBlock.h"
18 #include "llvm/IR/CallSite.h"
19 #include "llvm/IR/Metadata.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/IR/ProfileSummary.h"
24 // The following two parameters determine the threshold for a count to be
25 // considered hot/cold. These two parameters are percentile values (multiplied
26 // by 10000). If the counts are sorted in descending order, the minimum count to
27 // reach ProfileSummaryCutoffHot gives the threshold to determine a hot count.
28 // Similarly, the minimum count to reach ProfileSummaryCutoffCold gives the
29 // threshold for determining cold count (everything <= this threshold is
32 static cl::opt<int> ProfileSummaryCutoffHot(
33 "profile-summary-cutoff-hot", cl::Hidden, cl::init(999000), cl::ZeroOrMore,
34 cl::desc("A count is hot if it exceeds the minimum count to"
35 " reach this percentile of total counts."));
37 static cl::opt<int> ProfileSummaryCutoffCold(
38 "profile-summary-cutoff-cold", cl::Hidden, cl::init(999999), cl::ZeroOrMore,
39 cl::desc("A count is cold if it is below the minimum count"
40 " to reach this percentile of total counts."));
42 // Find the minimum count to reach a desired percentile of counts.
43 static uint64_t getMinCountForPercentile(SummaryEntryVector &DS,
44 uint64_t Percentile) {
45 auto Compare = [](const ProfileSummaryEntry &Entry, uint64_t Percentile) {
46 return Entry.Cutoff < Percentile;
48 auto It = std::lower_bound(DS.begin(), DS.end(), Percentile, Compare);
49 // The required percentile has to be <= one of the percentiles in the
52 report_fatal_error("Desired percentile exceeds the maximum cutoff");
56 // The profile summary metadata may be attached either by the frontend or by
57 // any backend passes (IR level instrumentation, for example). This method
58 // checks if the Summary is null and if so checks if the summary metadata is now
59 // available in the module and parses it to get the Summary object. Returns true
60 // if a valid Summary is available.
61 bool ProfileSummaryInfo::computeSummary() {
64 auto *SummaryMD = M.getProfileSummary();
67 Summary.reset(ProfileSummary::getFromMD(SummaryMD));
72 ProfileSummaryInfo::getProfileCount(const Instruction *Inst,
73 BlockFrequencyInfo *BFI) {
76 assert((isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) &&
77 "We can only get profile count for call/invoke instruction.");
78 // Check if there is a profile metadata on the instruction. If it is present,
79 // determine hotness solely based on that.
81 if (Inst->extractProfTotalWeight(TotalCount))
84 return BFI->getBlockProfileCount(Inst->getParent());
88 /// Returns true if the function's entry is hot. If it returns false, it
89 /// either means it is not hot or it is unknown whether it is hot or not (for
90 /// example, no profile data is available).
91 bool ProfileSummaryInfo::isFunctionEntryHot(const Function *F) {
92 if (!F || !computeSummary())
94 auto FunctionCount = F->getEntryCount();
95 // FIXME: The heuristic used below for determining hotness is based on
96 // preliminary SPEC tuning for inliner. This will eventually be a
97 // convenience method that calls isHotCount.
98 return FunctionCount && isHotCount(FunctionCount.getValue());
101 /// Returns true if the function's entry is a cold. If it returns false, it
102 /// either means it is not cold or it is unknown whether it is cold or not (for
103 /// example, no profile data is available).
104 bool ProfileSummaryInfo::isFunctionEntryCold(const Function *F) {
107 if (F->hasFnAttribute(Attribute::Cold)) {
110 if (!computeSummary())
112 auto FunctionCount = F->getEntryCount();
113 // FIXME: The heuristic used below for determining coldness is based on
114 // preliminary SPEC tuning for inliner. This will eventually be a
115 // convenience method that calls isHotCount.
116 return FunctionCount && isColdCount(FunctionCount.getValue());
119 /// Compute the hot and cold thresholds.
120 void ProfileSummaryInfo::computeThresholds() {
121 if (!computeSummary())
123 auto &DetailedSummary = Summary->getDetailedSummary();
125 getMinCountForPercentile(DetailedSummary, ProfileSummaryCutoffHot);
127 getMinCountForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
130 bool ProfileSummaryInfo::isHotCount(uint64_t C) {
131 if (!HotCountThreshold)
133 return HotCountThreshold && C >= HotCountThreshold.getValue();
136 bool ProfileSummaryInfo::isColdCount(uint64_t C) {
137 if (!ColdCountThreshold)
139 return ColdCountThreshold && C <= ColdCountThreshold.getValue();
142 bool ProfileSummaryInfo::isHotBB(const BasicBlock *B, BlockFrequencyInfo *BFI) {
143 auto Count = BFI->getBlockProfileCount(B);
144 return Count && isHotCount(*Count);
147 bool ProfileSummaryInfo::isColdBB(const BasicBlock *B,
148 BlockFrequencyInfo *BFI) {
149 auto Count = BFI->getBlockProfileCount(B);
150 return Count && isColdCount(*Count);
153 bool ProfileSummaryInfo::isHotCallSite(const CallSite &CS,
154 BlockFrequencyInfo *BFI) {
155 auto C = getProfileCount(CS.getInstruction(), BFI);
156 return C && isHotCount(*C);
159 bool ProfileSummaryInfo::isColdCallSite(const CallSite &CS,
160 BlockFrequencyInfo *BFI) {
161 auto C = getProfileCount(CS.getInstruction(), BFI);
162 return C && isColdCount(*C);
165 INITIALIZE_PASS(ProfileSummaryInfoWrapperPass, "profile-summary-info",
166 "Profile summary info", false, true)
168 ProfileSummaryInfoWrapperPass::ProfileSummaryInfoWrapperPass()
169 : ImmutablePass(ID) {
170 initializeProfileSummaryInfoWrapperPassPass(*PassRegistry::getPassRegistry());
173 bool ProfileSummaryInfoWrapperPass::doInitialization(Module &M) {
174 PSI.reset(new ProfileSummaryInfo(M));
178 bool ProfileSummaryInfoWrapperPass::doFinalization(Module &M) {
183 AnalysisKey ProfileSummaryAnalysis::Key;
184 ProfileSummaryInfo ProfileSummaryAnalysis::run(Module &M,
185 ModuleAnalysisManager &) {
186 return ProfileSummaryInfo(M);
189 PreservedAnalyses ProfileSummaryPrinterPass::run(Module &M,
190 ModuleAnalysisManager &AM) {
191 ProfileSummaryInfo &PSI = AM.getResult<ProfileSummaryAnalysis>(M);
193 OS << "Functions in " << M.getName() << " with hot/cold annotations: \n";
196 if (PSI.isFunctionEntryHot(&F))
197 OS << " :hot entry ";
198 else if (PSI.isFunctionEntryCold(&F))
199 OS << " :cold entry ";
202 return PreservedAnalyses::all();
205 char ProfileSummaryInfoWrapperPass::ID = 0;