LLVM  7.0.0svn
ProfileSummaryInfo.cpp
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1 //===- ProfileSummaryInfo.cpp - Global profile summary information --------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains a pass that provides access to the global profile summary
11 // information.
12 //
13 //===----------------------------------------------------------------------===//
14 
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"
22 using namespace llvm;
23 
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
30 // considered cold).
31 
33  "profile-summary-cutoff-hot", cl::Hidden, cl::init(990000), cl::ZeroOrMore,
34  cl::desc("A count is hot if it exceeds the minimum count to"
35  " reach this percentile of total counts."));
36 
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."));
41 
43  "profile-sample-accurate", cl::Hidden, cl::init(false),
44  cl::desc("If the sample profile is accurate, we will mark all un-sampled "
45  "callsite as cold. Otherwise, treat un-sampled callsites as if "
46  "we have no profile."));
48  "profile-summary-huge-working-set-size-threshold", cl::Hidden,
49  cl::init(15000), cl::ZeroOrMore,
50  cl::desc("The code working set size is considered huge if the number of"
51  " blocks required to reach the -profile-summary-cutoff-hot"
52  " percentile exceeds this count."));
53 
54 // Find the summary entry for a desired percentile of counts.
56  uint64_t Percentile) {
57  auto Compare = [](const ProfileSummaryEntry &Entry, uint64_t Percentile) {
58  return Entry.Cutoff < Percentile;
59  };
60  auto It = std::lower_bound(DS.begin(), DS.end(), Percentile, Compare);
61  // The required percentile has to be <= one of the percentiles in the
62  // detailed summary.
63  if (It == DS.end())
64  report_fatal_error("Desired percentile exceeds the maximum cutoff");
65  return *It;
66 }
67 
68 // The profile summary metadata may be attached either by the frontend or by
69 // any backend passes (IR level instrumentation, for example). This method
70 // checks if the Summary is null and if so checks if the summary metadata is now
71 // available in the module and parses it to get the Summary object. Returns true
72 // if a valid Summary is available.
73 bool ProfileSummaryInfo::computeSummary() {
74  if (Summary)
75  return true;
76  auto *SummaryMD = M.getProfileSummary();
77  if (!SummaryMD)
78  return false;
79  Summary.reset(ProfileSummary::getFromMD(SummaryMD));
80  return true;
81 }
82 
86  if (!Inst)
87  return None;
88  assert((isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) &&
89  "We can only get profile count for call/invoke instruction.");
90  if (hasSampleProfile()) {
91  // In sample PGO mode, check if there is a profile metadata on the
92  // instruction. If it is present, determine hotness solely based on that,
93  // since the sampled entry count may not be accurate. If there is no
94  // annotated on the instruction, return None.
95  uint64_t TotalCount;
96  if (Inst->extractProfTotalWeight(TotalCount))
97  return TotalCount;
98  return None;
99  }
100  if (BFI)
101  return BFI->getBlockProfileCount(Inst->getParent());
102  return None;
103 }
104 
105 /// Returns true if the function's entry is hot. If it returns false, it
106 /// either means it is not hot or it is unknown whether it is hot or not (for
107 /// example, no profile data is available).
109  if (!F || !computeSummary())
110  return false;
111  auto FunctionCount = F->getEntryCount();
112  // FIXME: The heuristic used below for determining hotness is based on
113  // preliminary SPEC tuning for inliner. This will eventually be a
114  // convenience method that calls isHotCount.
115  return FunctionCount && isHotCount(FunctionCount.getCount());
116 }
117 
118 /// Returns true if the function contains hot code. This can include a hot
119 /// function entry count, hot basic block, or (in the case of Sample PGO)
120 /// hot total call edge count.
121 /// If it returns false, it either means it is not hot or it is unknown
122 /// (for example, no profile data is available).
125  if (!F || !computeSummary())
126  return false;
127  if (auto FunctionCount = F->getEntryCount())
128  if (isHotCount(FunctionCount.getCount()))
129  return true;
130 
131  if (hasSampleProfile()) {
132  uint64_t TotalCallCount = 0;
133  for (const auto &BB : *F)
134  for (const auto &I : BB)
135  if (isa<CallInst>(I) || isa<InvokeInst>(I))
136  if (auto CallCount = getProfileCount(&I, nullptr))
137  TotalCallCount += CallCount.getValue();
138  if (isHotCount(TotalCallCount))
139  return true;
140  }
141  for (const auto &BB : *F)
142  if (isHotBB(&BB, &BFI))
143  return true;
144  return false;
145 }
146 
147 /// Returns true if the function only contains cold code. This means that
148 /// the function entry and blocks are all cold, and (in the case of Sample PGO)
149 /// the total call edge count is cold.
150 /// If it returns false, it either means it is not cold or it is unknown
151 /// (for example, no profile data is available).
154  if (!F || !computeSummary())
155  return false;
156  if (auto FunctionCount = F->getEntryCount())
157  if (!isColdCount(FunctionCount.getCount()))
158  return false;
159 
160  if (hasSampleProfile()) {
161  uint64_t TotalCallCount = 0;
162  for (const auto &BB : *F)
163  for (const auto &I : BB)
164  if (isa<CallInst>(I) || isa<InvokeInst>(I))
165  if (auto CallCount = getProfileCount(&I, nullptr))
166  TotalCallCount += CallCount.getValue();
167  if (!isColdCount(TotalCallCount))
168  return false;
169  }
170  for (const auto &BB : *F)
171  if (!isColdBB(&BB, &BFI))
172  return false;
173  return true;
174 }
175 
176 /// Returns true if the function's entry is a cold. If it returns false, it
177 /// either means it is not cold or it is unknown whether it is cold or not (for
178 /// example, no profile data is available).
180  if (!F)
181  return false;
183  return true;
184  if (!computeSummary())
185  return false;
186  auto FunctionCount = F->getEntryCount();
187  // FIXME: The heuristic used below for determining coldness is based on
188  // preliminary SPEC tuning for inliner. This will eventually be a
189  // convenience method that calls isHotCount.
190  return FunctionCount && isColdCount(FunctionCount.getCount());
191 }
192 
193 /// Compute the hot and cold thresholds.
194 void ProfileSummaryInfo::computeThresholds() {
195  if (!computeSummary())
196  return;
197  auto &DetailedSummary = Summary->getDetailedSummary();
198  auto &HotEntry =
200  HotCountThreshold = HotEntry.MinCount;
201  auto &ColdEntry =
203  ColdCountThreshold = ColdEntry.MinCount;
204  HasHugeWorkingSetSize =
205  HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
206 }
207 
209  if (!HasHugeWorkingSetSize)
210  computeThresholds();
211  return HasHugeWorkingSetSize && HasHugeWorkingSetSize.getValue();
212 }
213 
215  if (!HotCountThreshold)
216  computeThresholds();
217  return HotCountThreshold && C >= HotCountThreshold.getValue();
218 }
219 
221  if (!ColdCountThreshold)
222  computeThresholds();
223  return ColdCountThreshold && C <= ColdCountThreshold.getValue();
224 }
225 
227  if (!HotCountThreshold)
228  computeThresholds();
229  return HotCountThreshold && HotCountThreshold.getValue();
230 }
231 
233  if (!ColdCountThreshold)
234  computeThresholds();
235  return ColdCountThreshold && ColdCountThreshold.getValue();
236 }
237 
239  auto Count = BFI->getBlockProfileCount(B);
240  return Count && isHotCount(*Count);
241 }
242 
245  auto Count = BFI->getBlockProfileCount(B);
246  return Count && isColdCount(*Count);
247 }
248 
251  auto C = getProfileCount(CS.getInstruction(), BFI);
252  return C && isHotCount(*C);
253 }
254 
257  auto C = getProfileCount(CS.getInstruction(), BFI);
258  if (C)
259  return isColdCount(*C);
260 
261  // In SamplePGO, if the caller has been sampled, and there is no profile
262  // annotated on the callsite, we consider the callsite as cold.
263  // If there is no profile for the caller, and we know the profile is
264  // accurate, we consider the callsite as cold.
265  return (hasSampleProfile() &&
267  CS.getCaller()->hasFnAttribute("profile-sample-accurate")));
268 }
269 
271  "Profile summary info", false, true)
272 
274  : ImmutablePass(ID) {
276 }
277 
279  PSI.reset(new ProfileSummaryInfo(M));
280  return false;
281 }
282 
284  PSI.reset();
285  return false;
286 }
287 
288 AnalysisKey ProfileSummaryAnalysis::Key;
291  return ProfileSummaryInfo(M);
292 }
293 
295  ModuleAnalysisManager &AM) {
297 
298  OS << "Functions in " << M.getName() << " with hot/cold annotations: \n";
299  for (auto &F : M) {
300  OS << F.getName();
301  if (PSI.isFunctionEntryHot(&F))
302  OS << " :hot entry ";
303  else if (PSI.isFunctionEntryCold(&F))
304  OS << " :cold entry ";
305  OS << "\n";
306  }
307  return PreservedAnalyses::all();
308 }
309 
uint64_t CallInst * C
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:687
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:115
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:63
bool isColdBB(const BasicBlock *B, BlockFrequencyInfo *BFI)
Returns true if BasicBlock B is considered cold.
bool isColdCount(uint64_t C)
Returns true if count C is considered cold.
static cl::opt< bool > ProfileSampleAccurate("profile-sample-accurate", cl::Hidden, cl::init(false), cl::desc("If the sample profile is accurate, we will mark all un-sampled " "callsite as cold. Otherwise, treat un-sampled callsites as if " "we have no profile."))
Analysis providing profile information.
This file contains the declarations for metadata subclasses.
bool hasFnAttribute(Attribute::AttrKind Kind) const
Return true if the function has the attribute.
Definition: Function.h:307
Optional< uint64_t > getProfileCount(const Instruction *CallInst, BlockFrequencyInfo *BFI)
Returns the profile count for CallInst.
StringRef getName() const
Get a short "name" for the module.
Definition: Module.h:225
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 F is a hot function.
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.
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.
ProfileCount getEntryCount() const
Get the entry count for this function.
Definition: Function.cpp:1363
An analysis pass based on legacy pass manager to deliver ProfileSummaryInfo.
bool isHotBB(const BasicBlock *B, BlockFrequencyInfo *BFI)
Returns true if BasicBlock B is considered hot.
InstrTy * getInstruction() const
Definition: CallSite.h:92
Metadata * getProfileSummary()
Returns profile summary metadata.
Definition: Module.cpp:512
const T & getValue() const LLVM_LVALUE_FUNCTION
Definition: Optional.h:179
auto lower_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range))
Provide wrappers to std::lower_bound which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1004
bool extractProfTotalWeight(uint64_t &TotalVal) const
Retrieve total raw weight values of a branch.
Definition: Metadata.cpp:1340
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:410
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
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:59
bool hasSampleProfile()
Returns true if module M has sample profile.
An analysis pass based on the new PM to deliver ProfileSummaryInfo.
INITIALIZE_PASS(ProfileSummaryInfoWrapperPass, "profile-summary-info", "Profile summary info", false, true) ProfileSummaryInfoWrapperPass
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
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:256
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."))
FunTy * getCaller() const
Return the caller function for this call site.
Definition: CallSite.h:267
bool isFunctionEntryHot(const Function *F)
Returns true if F has hot function entry.
#define I(x, y, z)
Definition: MD5.cpp:58
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
bool hasProfileData() const
Return true if the function is annotated with profile data.
Definition: Function.h:294
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:70
Optional< uint64_t > getBlockProfileCount(const BasicBlock *BB) const
Returns the estimated profile count of BB.
static const ProfileSummaryEntry & getEntryForPercentile(SummaryEntryVector &DS, uint64_t Percentile)
const BasicBlock * getParent() const
Definition: Instruction.h:67