LLVM  9.0.0svn
ProfileSummaryInfo.cpp
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1 //===- ProfileSummaryInfo.cpp - Global profile summary information --------===//
2 //
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
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains a pass that provides access to the global profile summary
10 // information.
11 //
12 //===----------------------------------------------------------------------===//
13 
16 #include "llvm/IR/BasicBlock.h"
17 #include "llvm/IR/CallSite.h"
18 #include "llvm/IR/Metadata.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/IR/ProfileSummary.h"
21 using namespace llvm;
22 
23 // The following two parameters determine the threshold for a count to be
24 // considered hot/cold. These two parameters are percentile values (multiplied
25 // by 10000). If the counts are sorted in descending order, the minimum count to
26 // reach ProfileSummaryCutoffHot gives the threshold to determine a hot count.
27 // Similarly, the minimum count to reach ProfileSummaryCutoffCold gives the
28 // threshold for determining cold count (everything <= this threshold is
29 // considered cold).
30 
32  "profile-summary-cutoff-hot", cl::Hidden, cl::init(990000), cl::ZeroOrMore,
33  cl::desc("A count is hot if it exceeds the minimum count to"
34  " reach this percentile of total counts."));
35 
37  "profile-summary-cutoff-cold", cl::Hidden, cl::init(999999), cl::ZeroOrMore,
38  cl::desc("A count is cold if it is below the minimum count"
39  " to reach this percentile of total counts."));
40 
42  "profile-summary-huge-working-set-size-threshold", cl::Hidden,
43  cl::init(15000), cl::ZeroOrMore,
44  cl::desc("The code working set size is considered huge if the number of"
45  " blocks required to reach the -profile-summary-cutoff-hot"
46  " percentile exceeds this count."));
47 
48 // The next two options override the counts derived from summary computation and
49 // are useful for debugging purposes.
51  "profile-summary-hot-count", cl::ReallyHidden, cl::ZeroOrMore,
52  cl::desc("A fixed hot count that overrides the count derived from"
53  " profile-summary-cutoff-hot"));
54 
56  "profile-summary-cold-count", cl::ReallyHidden, cl::ZeroOrMore,
57  cl::desc("A fixed cold count that overrides the count derived from"
58  " profile-summary-cutoff-cold"));
59 
60 // Find the summary entry for a desired percentile of counts.
62  uint64_t Percentile) {
63  auto Compare = [](const ProfileSummaryEntry &Entry, uint64_t Percentile) {
64  return Entry.Cutoff < Percentile;
65  };
66  auto It = std::lower_bound(DS.begin(), DS.end(), Percentile, Compare);
67  // The required percentile has to be <= one of the percentiles in the
68  // detailed summary.
69  if (It == DS.end())
70  report_fatal_error("Desired percentile exceeds the maximum cutoff");
71  return *It;
72 }
73 
74 // The profile summary metadata may be attached either by the frontend or by
75 // any backend passes (IR level instrumentation, for example). This method
76 // checks if the Summary is null and if so checks if the summary metadata is now
77 // available in the module and parses it to get the Summary object. Returns true
78 // if a valid Summary is available.
79 bool ProfileSummaryInfo::computeSummary() {
80  if (Summary)
81  return true;
82  // First try to get context sensitive ProfileSummary.
83  auto *SummaryMD = M.getProfileSummary(/* IsCS */ true);
84  if (SummaryMD) {
85  Summary.reset(ProfileSummary::getFromMD(SummaryMD));
86  return true;
87  }
88  // This will actually return PSK_Instr or PSK_Sample summary.
89  SummaryMD = M.getProfileSummary(/* IsCS */ false);
90  if (!SummaryMD)
91  return false;
92  Summary.reset(ProfileSummary::getFromMD(SummaryMD));
93  return true;
94 }
95 
99  bool AllowSynthetic) {
100  if (!Inst)
101  return None;
102  assert((isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) &&
103  "We can only get profile count for call/invoke instruction.");
104  if (hasSampleProfile()) {
105  // In sample PGO mode, check if there is a profile metadata on the
106  // instruction. If it is present, determine hotness solely based on that,
107  // since the sampled entry count may not be accurate. If there is no
108  // annotated on the instruction, return None.
109  uint64_t TotalCount;
110  if (Inst->extractProfTotalWeight(TotalCount))
111  return TotalCount;
112  return None;
113  }
114  if (BFI)
115  return BFI->getBlockProfileCount(Inst->getParent(), AllowSynthetic);
116  return None;
117 }
118 
119 /// Returns true if the function's entry is hot. If it returns false, it
120 /// either means it is not hot or it is unknown whether it is hot or not (for
121 /// example, no profile data is available).
123  if (!F || !computeSummary())
124  return false;
125  auto FunctionCount = F->getEntryCount();
126  // FIXME: The heuristic used below for determining hotness is based on
127  // preliminary SPEC tuning for inliner. This will eventually be a
128  // convenience method that calls isHotCount.
129  return FunctionCount && isHotCount(FunctionCount.getCount());
130 }
131 
132 /// Returns true if the function contains hot code. This can include a hot
133 /// function entry count, hot basic block, or (in the case of Sample PGO)
134 /// hot total call edge count.
135 /// If it returns false, it either means it is not hot or it is unknown
136 /// (for example, no profile data is available).
139  if (!F || !computeSummary())
140  return false;
141  if (auto FunctionCount = F->getEntryCount())
142  if (isHotCount(FunctionCount.getCount()))
143  return true;
144 
145  if (hasSampleProfile()) {
146  uint64_t TotalCallCount = 0;
147  for (const auto &BB : *F)
148  for (const auto &I : BB)
149  if (isa<CallInst>(I) || isa<InvokeInst>(I))
150  if (auto CallCount = getProfileCount(&I, nullptr))
151  TotalCallCount += CallCount.getValue();
152  if (isHotCount(TotalCallCount))
153  return true;
154  }
155  for (const auto &BB : *F)
156  if (isHotBlock(&BB, &BFI))
157  return true;
158  return false;
159 }
160 
161 /// Returns true if the function only contains cold code. This means that
162 /// the function entry and blocks are all cold, and (in the case of Sample PGO)
163 /// the total call edge count is cold.
164 /// If it returns false, it either means it is not cold or it is unknown
165 /// (for example, no profile data is available).
168  if (!F || !computeSummary())
169  return false;
170  if (auto FunctionCount = F->getEntryCount())
171  if (!isColdCount(FunctionCount.getCount()))
172  return false;
173 
174  if (hasSampleProfile()) {
175  uint64_t TotalCallCount = 0;
176  for (const auto &BB : *F)
177  for (const auto &I : BB)
178  if (isa<CallInst>(I) || isa<InvokeInst>(I))
179  if (auto CallCount = getProfileCount(&I, nullptr))
180  TotalCallCount += CallCount.getValue();
181  if (!isColdCount(TotalCallCount))
182  return false;
183  }
184  for (const auto &BB : *F)
185  if (!isColdBlock(&BB, &BFI))
186  return false;
187  return true;
188 }
189 
190 /// Returns true if the function's entry is a cold. If it returns false, it
191 /// either means it is not cold or it is unknown whether it is cold or not (for
192 /// example, no profile data is available).
194  if (!F)
195  return false;
197  return true;
198  if (!computeSummary())
199  return false;
200  auto FunctionCount = F->getEntryCount();
201  // FIXME: The heuristic used below for determining coldness is based on
202  // preliminary SPEC tuning for inliner. This will eventually be a
203  // convenience method that calls isHotCount.
204  return FunctionCount && isColdCount(FunctionCount.getCount());
205 }
206 
207 /// Compute the hot and cold thresholds.
208 void ProfileSummaryInfo::computeThresholds() {
209  if (!computeSummary())
210  return;
211  auto &DetailedSummary = Summary->getDetailedSummary();
212  auto &HotEntry =
214  HotCountThreshold = HotEntry.MinCount;
215  if (ProfileSummaryHotCount.getNumOccurrences() > 0)
216  HotCountThreshold = ProfileSummaryHotCount;
217  auto &ColdEntry =
219  ColdCountThreshold = ColdEntry.MinCount;
220  if (ProfileSummaryColdCount.getNumOccurrences() > 0)
221  ColdCountThreshold = ProfileSummaryColdCount;
222  assert(ColdCountThreshold <= HotCountThreshold &&
223  "Cold count threshold cannot exceed hot count threshold!");
224  HasHugeWorkingSetSize =
225  HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
226 }
227 
229  if (!HasHugeWorkingSetSize)
230  computeThresholds();
231  return HasHugeWorkingSetSize && HasHugeWorkingSetSize.getValue();
232 }
233 
235  if (!HotCountThreshold)
236  computeThresholds();
237  return HotCountThreshold && C >= HotCountThreshold.getValue();
238 }
239 
241  if (!ColdCountThreshold)
242  computeThresholds();
243  return ColdCountThreshold && C <= ColdCountThreshold.getValue();
244 }
245 
247  if (!HotCountThreshold)
248  computeThresholds();
249  return HotCountThreshold ? HotCountThreshold.getValue() : UINT64_MAX;
250 }
251 
253  if (!ColdCountThreshold)
254  computeThresholds();
255  return ColdCountThreshold ? ColdCountThreshold.getValue() : 0;
256 }
257 
259  auto Count = BFI->getBlockProfileCount(BB);
260  return Count && isHotCount(*Count);
261 }
262 
265  auto Count = BFI->getBlockProfileCount(BB);
266  return Count && isColdCount(*Count);
267 }
268 
271  auto C = getProfileCount(CS.getInstruction(), BFI);
272  return C && isHotCount(*C);
273 }
274 
277  auto C = getProfileCount(CS.getInstruction(), BFI);
278  if (C)
279  return isColdCount(*C);
280 
281  // In SamplePGO, if the caller has been sampled, and there is no profile
282  // annotated on the callsite, we consider the callsite as cold.
283  return hasSampleProfile() && CS.getCaller()->hasProfileData();
284 }
285 
287  "Profile summary info", false, true)
288 
290  : ImmutablePass(ID) {
292 }
293 
295  PSI.reset(new ProfileSummaryInfo(M));
296  return false;
297 }
298 
300  PSI.reset();
301  return false;
302 }
303 
304 AnalysisKey ProfileSummaryAnalysis::Key;
307  return ProfileSummaryInfo(M);
308 }
309 
311  ModuleAnalysisManager &AM) {
313 
314  OS << "Functions in " << M.getName() << " with hot/cold annotations: \n";
315  for (auto &F : M) {
316  OS << F.getName();
317  if (PSI.isFunctionEntryHot(&F))
318  OS << " :hot entry ";
319  else if (PSI.isFunctionEntryCold(&F))
320  OS << " :cold entry ";
321  OS << "\n";
322  }
323  return PreservedAnalyses::all();
324 }
325 
auto lower_bound(R &&Range, T &&Value) -> decltype(adl_begin(Range))
Provide wrappers to std::lower_bound which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1281
uint64_t CallInst * C
Optional< uint64_t > getBlockProfileCount(const BasicBlock *BB, bool AllowSynthetic=false) const
Returns the estimated profile count of BB.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
uint32_t Cutoff
The required percentile of counts.
PassT::Result & getResult(IRUnitT &IR, ExtraArgTs... ExtraArgs)
Get the result of an analysis pass for a given IR unit.
Definition: PassManager.h:776
LLVM_ATTRIBUTE_NORETURN void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:139
This class represents lattice values for constants.
Definition: AllocatorList.h:23
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:65
bool isColdCount(uint64_t C)
Returns true if count C is considered cold.
Analysis providing profile information.
This file contains the declarations for metadata subclasses.
Metadata * getProfileSummary(bool IsCS)
Returns profile summary metadata.
Definition: Module.cpp:541
bool hasFnAttribute(Attribute::AttrKind Kind) const
Return true if the function has the attribute.
Definition: Function.h:323
StringRef getName() const
Get a short "name" for the module.
Definition: Module.h:227
F(f)
uint64_t getOrCompHotCountThreshold()
Returns HotCountThreshold if set.
static cl::opt< unsigned > ProfileSummaryHugeWorkingSetSizeThreshold("profile-summary-huge-working-set-size-threshold", cl::Hidden, cl::init(15000), cl::ZeroOrMore, cl::desc("The code working set size is considered huge if the number of" " blocks required to reach the -profile-summary-cutoff-hot" " percentile exceeds this count."))
bool isHotCount(uint64_t C)
Returns true if count C is considered hot.
bool isFunctionEntryCold(const Function *F)
Returns true if F has cold function entry.
bool isHotCallSite(const CallSite &CS, BlockFrequencyInfo *BFI)
Returns true if CallSite CS is considered hot.
static cl::opt< int > ProfileSummaryHotCount("profile-summary-hot-count", cl::ReallyHidden, cl::ZeroOrMore, cl::desc("A fixed hot count that overrides the count derived from" " profile-summary-cutoff-hot"))
uint64_t getOrCompColdCountThreshold()
Returns ColdCountThreshold if set.
Result run(Module &M, ModuleAnalysisManager &)
bool isFunctionHotInCallGraph(const Function *F, BlockFrequencyInfo &BFI)
Returns true if F contains hot code.
An analysis pass based on legacy pass manager to deliver ProfileSummaryInfo.
InstrTy * getInstruction() const
Definition: CallSite.h:96
bool isColdBlock(const BasicBlock *BB, BlockFrequencyInfo *BFI)
Returns true if BasicBlock BB is considered cold.
#define UINT64_MAX
Definition: DataTypes.h:83
const T & getValue() const LLVM_LVALUE_FUNCTION
Definition: Optional.h:255
bool extractProfTotalWeight(uint64_t &TotalVal) const
Retrieve total raw weight values of a branch.
Definition: Metadata.cpp:1336
bool doInitialization(Module &M) override
doInitialization - Virtual method overridden by subclasses to do any necessary initialization before ...
BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to estimate IR basic block frequen...
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:432
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:153
LLVM Basic Block Representation.
Definition: BasicBlock.h:57
bool hasSampleProfile()
Returns true if module M has sample profile.
An analysis pass based on the new PM to deliver ProfileSummaryInfo.
ProfileCount getEntryCount(bool AllowSynthetic=false) const
Get the entry count for this function.
Definition: Function.cpp:1388
INITIALIZE_PASS(ProfileSummaryInfoWrapperPass, "profile-summary-info", "Profile summary info", false, true) ProfileSummaryInfoWrapperPass
bool hasProfileData(bool IncludeSynthetic=false) const
Return true if the function is annotated with profile data.
Definition: Function.h:308
bool doFinalization(Module &M) override
doFinalization - Virtual method overriden by subclasses to do any necessary clean up after all passes...
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: PassManager.h:159
Optional< uint64_t > getProfileCount(const Instruction *CallInst, BlockFrequencyInfo *BFI, bool AllowSynthetic=false)
Returns the profile count for CallInst.
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM)
ImmutablePass class - This class is used to provide information that does not need to be run...
Definition: Pass.h:255
Module.h This file contains the declarations for the Module class.
void initializeProfileSummaryInfoWrapperPassPass(PassRegistry &)
bool isFunctionColdInCallGraph(const Function *F, BlockFrequencyInfo &BFI)
Returns true if F contains only cold code.
static ProfileSummary * getFromMD(Metadata *MD)
Construct profile summary from metdata.
static cl::opt< int > ProfileSummaryCutoffHot("profile-summary-cutoff-hot", cl::Hidden, cl::init(990000), cl::ZeroOrMore, cl::desc("A count is hot if it exceeds the minimum count to" " reach this percentile of total counts."))
bool isFunctionEntryHot(const Function *F)
Returns true if F has hot function entry.
#define I(x, y, z)
Definition: MD5.cpp:58
bool isHotBlock(const BasicBlock *BB, BlockFrequencyInfo *BFI)
Returns true if BasicBlock BB is considered hot.
bool isColdCallSite(const CallSite &CS, BlockFrequencyInfo *BFI)
Returns true if Callsite CS is considered cold.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
bool hasHugeWorkingSetSize()
Returns true if the working set size of the code is considered huge.
static cl::opt< int > ProfileSummaryCutoffCold("profile-summary-cutoff-cold", cl::Hidden, cl::init(999999), cl::ZeroOrMore, cl::desc("A count is cold if it is below the minimum count" " to reach this percentile of total counts."))
A container for analyses that lazily runs them and caches their results.
std::vector< ProfileSummaryEntry > SummaryEntryVector
static cl::opt< int > ProfileSummaryColdCount("profile-summary-cold-count", cl::ReallyHidden, cl::ZeroOrMore, cl::desc("A fixed cold count that overrides the count derived from" " profile-summary-cutoff-cold"))
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:70
static const ProfileSummaryEntry & getEntryForPercentile(SummaryEntryVector &DS, uint64_t Percentile)
const BasicBlock * getParent() const
Definition: Instruction.h:66
FunTy * getCaller() const
Return the caller function for this call site.
Definition: CallSite.h:275