1 //=-- InstrProf.cpp - Instrumented profiling format support -----------------=//
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 support for clang's instrumentation based PGO and
11 // coverage.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/ProfileData/InstrProf.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/IR/Constants.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/IR/GlobalVariable.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/Support/Compression.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/LEB128.h"
24 #include "llvm/Support/ManagedStatic.h"
25 
26 using namespace llvm;
27 
28 namespace {
29 class InstrProfErrorCategoryType : public std::error_category {
30   const char *name() const LLVM_NOEXCEPT override { return "llvm.instrprof"; }
31   std::string message(int IE) const override {
32     instrprof_error E = static_cast<instrprof_error>(IE);
33     switch (E) {
34     case instrprof_error::success:
35       return "Success";
36     case instrprof_error::eof:
37       return "End of File";
38     case instrprof_error::unrecognized_format:
39       return "Unrecognized instrumentation profile encoding format";
40     case instrprof_error::bad_magic:
41       return "Invalid instrumentation profile data (bad magic)";
42     case instrprof_error::bad_header:
43       return "Invalid instrumentation profile data (file header is corrupt)";
44     case instrprof_error::unsupported_version:
45       return "Unsupported instrumentation profile format version";
46     case instrprof_error::unsupported_hash_type:
47       return "Unsupported instrumentation profile hash type";
48     case instrprof_error::too_large:
49       return "Too much profile data";
50     case instrprof_error::truncated:
51       return "Truncated profile data";
52     case instrprof_error::malformed:
53       return "Malformed instrumentation profile data";
54     case instrprof_error::unknown_function:
55       return "No profile data available for function";
56     case instrprof_error::hash_mismatch:
57       return "Function control flow change detected (hash mismatch)";
58     case instrprof_error::count_mismatch:
59       return "Function basic block count change detected (counter mismatch)";
60     case instrprof_error::counter_overflow:
61       return "Counter overflow";
62     case instrprof_error::value_site_count_mismatch:
63       return "Function value site count change detected (counter mismatch)";
64     }
65     llvm_unreachable("A value of instrprof_error has no message.");
66   }
67 };
68 } // end anonymous namespace
69 
70 static ManagedStatic<InstrProfErrorCategoryType> ErrorCategory;
71 
72 const std::error_category &llvm::instrprof_category() {
73   return *ErrorCategory;
74 }
75 
76 namespace llvm {
77 
78 std::string getPGOFuncName(StringRef RawFuncName,
79                            GlobalValue::LinkageTypes Linkage,
80                            StringRef FileName,
81                            uint64_t Version LLVM_ATTRIBUTE_UNUSED) {
82 
83   // Function names may be prefixed with a binary '1' to indicate
84   // that the backend should not modify the symbols due to any platform
85   // naming convention. Do not include that '1' in the PGO profile name.
86   if (RawFuncName[0] == '\1')
87     RawFuncName = RawFuncName.substr(1);
88 
89   std::string FuncName = RawFuncName;
90   if (llvm::GlobalValue::isLocalLinkage(Linkage)) {
91     // For local symbols, prepend the main file name to distinguish them.
92     // Do not include the full path in the file name since there's no guarantee
93     // that it will stay the same, e.g., if the files are checked out from
94     // version control in different locations.
95     if (FileName.empty())
96       FuncName = FuncName.insert(0, "<unknown>:");
97     else
98       FuncName = FuncName.insert(0, FileName.str() + ":");
99   }
100   return FuncName;
101 }
102 
103 std::string getPGOFuncName(const Function &F, uint64_t Version) {
104   return getPGOFuncName(F.getName(), F.getLinkage(), F.getParent()->getName(),
105                         Version);
106 }
107 
108 StringRef getFuncNameWithoutPrefix(StringRef PGOFuncName, StringRef FileName) {
109   if (FileName.empty())
110     return PGOFuncName;
111   // Drop the file name including ':'. See also getPGOFuncName.
112   if (PGOFuncName.startswith(FileName))
113     PGOFuncName = PGOFuncName.drop_front(FileName.size() + 1);
114   return PGOFuncName;
115 }
116 
117 // \p FuncName is the string used as profile lookup key for the function. A
118 // symbol is created to hold the name. Return the legalized symbol name.
119 static std::string getPGOFuncNameVarName(StringRef FuncName,
120                                          GlobalValue::LinkageTypes Linkage) {
121   std::string VarName = getInstrProfNameVarPrefix();
122   VarName += FuncName;
123 
124   if (!GlobalValue::isLocalLinkage(Linkage))
125     return VarName;
126 
127   // Now fix up illegal chars in local VarName that may upset the assembler.
128   const char *InvalidChars = "-:<>\"'";
129   size_t found = VarName.find_first_of(InvalidChars);
130   while (found != std::string::npos) {
131     VarName[found] = '_';
132     found = VarName.find_first_of(InvalidChars, found + 1);
133   }
134   return VarName;
135 }
136 
137 GlobalVariable *createPGOFuncNameVar(Module &M,
138                                      GlobalValue::LinkageTypes Linkage,
139                                      StringRef FuncName) {
140 
141   // We generally want to match the function's linkage, but available_externally
142   // and extern_weak both have the wrong semantics, and anything that doesn't
143   // need to link across compilation units doesn't need to be visible at all.
144   if (Linkage == GlobalValue::ExternalWeakLinkage)
145     Linkage = GlobalValue::LinkOnceAnyLinkage;
146   else if (Linkage == GlobalValue::AvailableExternallyLinkage)
147     Linkage = GlobalValue::LinkOnceODRLinkage;
148   else if (Linkage == GlobalValue::InternalLinkage ||
149            Linkage == GlobalValue::ExternalLinkage)
150     Linkage = GlobalValue::PrivateLinkage;
151 
152   auto *Value = ConstantDataArray::getString(M.getContext(), FuncName, false);
153   auto FuncNameVar =
154       new GlobalVariable(M, Value->getType(), true, Linkage, Value,
155                          getPGOFuncNameVarName(FuncName, Linkage));
156 
157   // Hide the symbol so that we correctly get a copy for each executable.
158   if (!GlobalValue::isLocalLinkage(FuncNameVar->getLinkage()))
159     FuncNameVar->setVisibility(GlobalValue::HiddenVisibility);
160 
161   return FuncNameVar;
162 }
163 
164 GlobalVariable *createPGOFuncNameVar(Function &F, StringRef FuncName) {
165   return createPGOFuncNameVar(*F.getParent(), F.getLinkage(), FuncName);
166 }
167 
168 void InstrProfSymtab::create(const Module &M) {
169   for (const Function &F : M)
170     addFuncName(getPGOFuncName(F));
171 
172   finalizeSymtab();
173 }
174 
175 int collectPGOFuncNameStrings(const std::vector<std::string> &NameStrs,
176                               bool doCompression, std::string &Result) {
177   uint8_t Header[16], *P = Header;
178   std::string UncompressedNameStrings =
179       join(NameStrs.begin(), NameStrs.end(), StringRef(" "));
180 
181   unsigned EncLen = encodeULEB128(UncompressedNameStrings.length(), P);
182   P += EncLen;
183 
184   auto WriteStringToResult = [&](size_t CompressedLen,
185                                  const std::string &InputStr) {
186     EncLen = encodeULEB128(CompressedLen, P);
187     P += EncLen;
188     char *HeaderStr = reinterpret_cast<char *>(&Header[0]);
189     unsigned HeaderLen = P - &Header[0];
190     Result.append(HeaderStr, HeaderLen);
191     Result += InputStr;
192     return 0;
193   };
194 
195   if (!doCompression)
196     return WriteStringToResult(0, UncompressedNameStrings);
197 
198   SmallVector<char, 128> CompressedNameStrings;
199   zlib::Status Success =
200       zlib::compress(StringRef(UncompressedNameStrings), CompressedNameStrings,
201                      zlib::BestSizeCompression);
202 
203   if (Success != zlib::StatusOK)
204     return 1;
205 
206   return WriteStringToResult(
207       CompressedNameStrings.size(),
208       std::string(CompressedNameStrings.data(), CompressedNameStrings.size()));
209 }
210 
211 StringRef getPGOFuncNameInitializer(GlobalVariable *NameVar) {
212   auto *Arr = cast<ConstantDataArray>(NameVar->getInitializer());
213   StringRef NameStr =
214       Arr->isCString() ? Arr->getAsCString() : Arr->getAsString();
215   return NameStr;
216 }
217 
218 int collectPGOFuncNameStrings(const std::vector<GlobalVariable *> &NameVars,
219                               std::string &Result, bool doCompression) {
220   std::vector<std::string> NameStrs;
221   for (auto *NameVar : NameVars) {
222     NameStrs.push_back(getPGOFuncNameInitializer(NameVar));
223   }
224   return collectPGOFuncNameStrings(
225       NameStrs, zlib::isAvailable() && doCompression, Result);
226 }
227 
228 int readPGOFuncNameStrings(StringRef NameStrings, InstrProfSymtab &Symtab) {
229   const uint8_t *P = reinterpret_cast<const uint8_t *>(NameStrings.data());
230   const uint8_t *EndP = reinterpret_cast<const uint8_t *>(NameStrings.data() +
231                                                           NameStrings.size());
232   while (P < EndP) {
233     uint32_t N;
234     uint64_t UncompressedSize = decodeULEB128(P, &N);
235     P += N;
236     uint64_t CompressedSize = decodeULEB128(P, &N);
237     P += N;
238     bool isCompressed = (CompressedSize != 0);
239     SmallString<128> UncompressedNameStrings;
240     StringRef NameStrings;
241     if (isCompressed) {
242       StringRef CompressedNameStrings(reinterpret_cast<const char *>(P),
243                                       CompressedSize);
244       if (zlib::uncompress(CompressedNameStrings, UncompressedNameStrings,
245                            UncompressedSize) != zlib::StatusOK)
246         return 1;
247       P += CompressedSize;
248       NameStrings = StringRef(UncompressedNameStrings.data(),
249                               UncompressedNameStrings.size());
250     } else {
251       NameStrings =
252           StringRef(reinterpret_cast<const char *>(P), UncompressedSize);
253       P += UncompressedSize;
254     }
255     // Now parse the name strings.
256     SmallVector<StringRef, 0> Names;
257     NameStrings.split(Names, ' ');
258     for (StringRef &Name : Names)
259       Symtab.addFuncName(Name);
260 
261     while (P < EndP && *P == 0)
262       P++;
263   }
264   Symtab.finalizeSymtab();
265   return 0;
266 }
267 
268 instrprof_error InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord &Input,
269                                                 uint64_t Weight) {
270   this->sortByTargetValues();
271   Input.sortByTargetValues();
272   auto I = ValueData.begin();
273   auto IE = ValueData.end();
274   instrprof_error Result = instrprof_error::success;
275   for (auto J = Input.ValueData.begin(), JE = Input.ValueData.end(); J != JE;
276        ++J) {
277     while (I != IE && I->Value < J->Value)
278       ++I;
279     if (I != IE && I->Value == J->Value) {
280       bool Overflowed;
281       I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count, &Overflowed);
282       if (Overflowed)
283         Result = instrprof_error::counter_overflow;
284       ++I;
285       continue;
286     }
287     ValueData.insert(I, *J);
288   }
289   return Result;
290 }
291 
292 instrprof_error InstrProfValueSiteRecord::scale(uint64_t Weight) {
293   instrprof_error Result = instrprof_error::success;
294   for (auto I = ValueData.begin(), IE = ValueData.end(); I != IE; ++I) {
295     bool Overflowed;
296     I->Count = SaturatingMultiply(I->Count, Weight, &Overflowed);
297     if (Overflowed)
298       Result = instrprof_error::counter_overflow;
299   }
300   return Result;
301 }
302 
303 // Merge Value Profile data from Src record to this record for ValueKind.
304 // Scale merged value counts by \p Weight.
305 instrprof_error InstrProfRecord::mergeValueProfData(uint32_t ValueKind,
306                                                     InstrProfRecord &Src,
307                                                     uint64_t Weight) {
308   uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
309   uint32_t OtherNumValueSites = Src.getNumValueSites(ValueKind);
310   if (ThisNumValueSites != OtherNumValueSites)
311     return instrprof_error::value_site_count_mismatch;
312   std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
313       getValueSitesForKind(ValueKind);
314   std::vector<InstrProfValueSiteRecord> &OtherSiteRecords =
315       Src.getValueSitesForKind(ValueKind);
316   instrprof_error Result = instrprof_error::success;
317   for (uint32_t I = 0; I < ThisNumValueSites; I++)
318     MergeResult(Result, ThisSiteRecords[I].merge(OtherSiteRecords[I], Weight));
319   return Result;
320 }
321 
322 instrprof_error InstrProfRecord::merge(InstrProfRecord &Other,
323                                        uint64_t Weight) {
324   // If the number of counters doesn't match we either have bad data
325   // or a hash collision.
326   if (Counts.size() != Other.Counts.size())
327     return instrprof_error::count_mismatch;
328 
329   instrprof_error Result = instrprof_error::success;
330 
331   for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
332     bool Overflowed;
333     Counts[I] =
334         SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I], &Overflowed);
335     if (Overflowed)
336       Result = instrprof_error::counter_overflow;
337   }
338 
339   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
340     MergeResult(Result, mergeValueProfData(Kind, Other, Weight));
341 
342   return Result;
343 }
344 
345 instrprof_error InstrProfRecord::scaleValueProfData(uint32_t ValueKind,
346                                                     uint64_t Weight) {
347   uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
348   std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
349       getValueSitesForKind(ValueKind);
350   instrprof_error Result = instrprof_error::success;
351   for (uint32_t I = 0; I < ThisNumValueSites; I++)
352     MergeResult(Result, ThisSiteRecords[I].scale(Weight));
353   return Result;
354 }
355 
356 instrprof_error InstrProfRecord::scale(uint64_t Weight) {
357   instrprof_error Result = instrprof_error::success;
358   for (auto &Count : this->Counts) {
359     bool Overflowed;
360     Count = SaturatingMultiply(Count, Weight, &Overflowed);
361     if (Overflowed && Result == instrprof_error::success) {
362       Result = instrprof_error::counter_overflow;
363     }
364   }
365   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
366     MergeResult(Result, scaleValueProfData(Kind, Weight));
367 
368   return Result;
369 }
370 
371 // Map indirect call target name hash to name string.
372 uint64_t InstrProfRecord::remapValue(uint64_t Value, uint32_t ValueKind,
373                                      ValueMapType *ValueMap) {
374   if (!ValueMap)
375     return Value;
376   switch (ValueKind) {
377   case IPVK_IndirectCallTarget: {
378     auto Result =
379         std::lower_bound(ValueMap->begin(), ValueMap->end(), Value,
380                          [](const std::pair<uint64_t, uint64_t> &LHS,
381                             uint64_t RHS) { return LHS.first < RHS; });
382     if (Result != ValueMap->end())
383       Value = (uint64_t)Result->second;
384     break;
385   }
386   }
387   return Value;
388 }
389 
390 void InstrProfRecord::addValueData(uint32_t ValueKind, uint32_t Site,
391                                    InstrProfValueData *VData, uint32_t N,
392                                    ValueMapType *ValueMap) {
393   for (uint32_t I = 0; I < N; I++) {
394     VData[I].Value = remapValue(VData[I].Value, ValueKind, ValueMap);
395   }
396   std::vector<InstrProfValueSiteRecord> &ValueSites =
397       getValueSitesForKind(ValueKind);
398   if (N == 0)
399     ValueSites.push_back(InstrProfValueSiteRecord());
400   else
401     ValueSites.emplace_back(VData, VData + N);
402 }
403 
404 #define INSTR_PROF_COMMON_API_IMPL
405 #include "llvm/ProfileData/InstrProfData.inc"
406 
407 /*!
408  * \brief ValueProfRecordClosure Interface implementation for  InstrProfRecord
409  *  class. These C wrappers are used as adaptors so that C++ code can be
410  *  invoked as callbacks.
411  */
412 uint32_t getNumValueKindsInstrProf(const void *Record) {
413   return reinterpret_cast<const InstrProfRecord *>(Record)->getNumValueKinds();
414 }
415 
416 uint32_t getNumValueSitesInstrProf(const void *Record, uint32_t VKind) {
417   return reinterpret_cast<const InstrProfRecord *>(Record)
418       ->getNumValueSites(VKind);
419 }
420 
421 uint32_t getNumValueDataInstrProf(const void *Record, uint32_t VKind) {
422   return reinterpret_cast<const InstrProfRecord *>(Record)
423       ->getNumValueData(VKind);
424 }
425 
426 uint32_t getNumValueDataForSiteInstrProf(const void *R, uint32_t VK,
427                                          uint32_t S) {
428   return reinterpret_cast<const InstrProfRecord *>(R)
429       ->getNumValueDataForSite(VK, S);
430 }
431 
432 void getValueForSiteInstrProf(const void *R, InstrProfValueData *Dst,
433                               uint32_t K, uint32_t S,
434                               uint64_t (*Mapper)(uint32_t, uint64_t)) {
435   return reinterpret_cast<const InstrProfRecord *>(R)->getValueForSite(
436       Dst, K, S, Mapper);
437 }
438 
439 ValueProfData *allocValueProfDataInstrProf(size_t TotalSizeInBytes) {
440   ValueProfData *VD =
441       (ValueProfData *)(new (::operator new(TotalSizeInBytes)) ValueProfData());
442   memset(VD, 0, TotalSizeInBytes);
443   return VD;
444 }
445 
446 static ValueProfRecordClosure InstrProfRecordClosure = {
447     nullptr,
448     getNumValueKindsInstrProf,
449     getNumValueSitesInstrProf,
450     getNumValueDataInstrProf,
451     getNumValueDataForSiteInstrProf,
452     nullptr,
453     getValueForSiteInstrProf,
454     allocValueProfDataInstrProf};
455 
456 // Wrapper implementation using the closure mechanism.
457 uint32_t ValueProfData::getSize(const InstrProfRecord &Record) {
458   InstrProfRecordClosure.Record = &Record;
459   return getValueProfDataSize(&InstrProfRecordClosure);
460 }
461 
462 // Wrapper implementation using the closure mechanism.
463 std::unique_ptr<ValueProfData>
464 ValueProfData::serializeFrom(const InstrProfRecord &Record) {
465   InstrProfRecordClosure.Record = &Record;
466 
467   std::unique_ptr<ValueProfData> VPD(
468       serializeValueProfDataFrom(&InstrProfRecordClosure, nullptr));
469   return VPD;
470 }
471 
472 void ValueProfRecord::deserializeTo(InstrProfRecord &Record,
473                                     InstrProfRecord::ValueMapType *VMap) {
474   Record.reserveSites(Kind, NumValueSites);
475 
476   InstrProfValueData *ValueData = getValueProfRecordValueData(this);
477   for (uint64_t VSite = 0; VSite < NumValueSites; ++VSite) {
478     uint8_t ValueDataCount = this->SiteCountArray[VSite];
479     Record.addValueData(Kind, VSite, ValueData, ValueDataCount, VMap);
480     ValueData += ValueDataCount;
481   }
482 }
483 
484 // For writing/serializing,  Old is the host endianness, and  New is
485 // byte order intended on disk. For Reading/deserialization, Old
486 // is the on-disk source endianness, and New is the host endianness.
487 void ValueProfRecord::swapBytes(support::endianness Old,
488                                 support::endianness New) {
489   using namespace support;
490   if (Old == New)
491     return;
492 
493   if (getHostEndianness() != Old) {
494     sys::swapByteOrder<uint32_t>(NumValueSites);
495     sys::swapByteOrder<uint32_t>(Kind);
496   }
497   uint32_t ND = getValueProfRecordNumValueData(this);
498   InstrProfValueData *VD = getValueProfRecordValueData(this);
499 
500   // No need to swap byte array: SiteCountArrray.
501   for (uint32_t I = 0; I < ND; I++) {
502     sys::swapByteOrder<uint64_t>(VD[I].Value);
503     sys::swapByteOrder<uint64_t>(VD[I].Count);
504   }
505   if (getHostEndianness() == Old) {
506     sys::swapByteOrder<uint32_t>(NumValueSites);
507     sys::swapByteOrder<uint32_t>(Kind);
508   }
509 }
510 
511 void ValueProfData::deserializeTo(InstrProfRecord &Record,
512                                   InstrProfRecord::ValueMapType *VMap) {
513   if (NumValueKinds == 0)
514     return;
515 
516   ValueProfRecord *VR = getFirstValueProfRecord(this);
517   for (uint32_t K = 0; K < NumValueKinds; K++) {
518     VR->deserializeTo(Record, VMap);
519     VR = getValueProfRecordNext(VR);
520   }
521 }
522 
523 template <class T>
524 static T swapToHostOrder(const unsigned char *&D, support::endianness Orig) {
525   using namespace support;
526   if (Orig == little)
527     return endian::readNext<T, little, unaligned>(D);
528   else
529     return endian::readNext<T, big, unaligned>(D);
530 }
531 
532 static std::unique_ptr<ValueProfData> allocValueProfData(uint32_t TotalSize) {
533   return std::unique_ptr<ValueProfData>(new (::operator new(TotalSize))
534                                             ValueProfData());
535 }
536 
537 instrprof_error ValueProfData::checkIntegrity() {
538   if (NumValueKinds > IPVK_Last + 1)
539     return instrprof_error::malformed;
540   // Total size needs to be mulltiple of quadword size.
541   if (TotalSize % sizeof(uint64_t))
542     return instrprof_error::malformed;
543 
544   ValueProfRecord *VR = getFirstValueProfRecord(this);
545   for (uint32_t K = 0; K < this->NumValueKinds; K++) {
546     if (VR->Kind > IPVK_Last)
547       return instrprof_error::malformed;
548     VR = getValueProfRecordNext(VR);
549     if ((char *)VR - (char *)this > (ptrdiff_t)TotalSize)
550       return instrprof_error::malformed;
551   }
552   return instrprof_error::success;
553 }
554 
555 ErrorOr<std::unique_ptr<ValueProfData>>
556 ValueProfData::getValueProfData(const unsigned char *D,
557                                 const unsigned char *const BufferEnd,
558                                 support::endianness Endianness) {
559   using namespace support;
560   if (D + sizeof(ValueProfData) > BufferEnd)
561     return instrprof_error::truncated;
562 
563   const unsigned char *Header = D;
564   uint32_t TotalSize = swapToHostOrder<uint32_t>(Header, Endianness);
565   if (D + TotalSize > BufferEnd)
566     return instrprof_error::too_large;
567 
568   std::unique_ptr<ValueProfData> VPD = allocValueProfData(TotalSize);
569   memcpy(VPD.get(), D, TotalSize);
570   // Byte swap.
571   VPD->swapBytesToHost(Endianness);
572 
573   instrprof_error EC = VPD->checkIntegrity();
574   if (EC != instrprof_error::success)
575     return EC;
576 
577   return std::move(VPD);
578 }
579 
580 void ValueProfData::swapBytesToHost(support::endianness Endianness) {
581   using namespace support;
582   if (Endianness == getHostEndianness())
583     return;
584 
585   sys::swapByteOrder<uint32_t>(TotalSize);
586   sys::swapByteOrder<uint32_t>(NumValueKinds);
587 
588   ValueProfRecord *VR = getFirstValueProfRecord(this);
589   for (uint32_t K = 0; K < NumValueKinds; K++) {
590     VR->swapBytes(Endianness, getHostEndianness());
591     VR = getValueProfRecordNext(VR);
592   }
593 }
594 
595 void ValueProfData::swapBytesFromHost(support::endianness Endianness) {
596   using namespace support;
597   if (Endianness == getHostEndianness())
598     return;
599 
600   ValueProfRecord *VR = getFirstValueProfRecord(this);
601   for (uint32_t K = 0; K < NumValueKinds; K++) {
602     ValueProfRecord *NVR = getValueProfRecordNext(VR);
603     VR->swapBytes(getHostEndianness(), Endianness);
604     VR = NVR;
605   }
606   sys::swapByteOrder<uint32_t>(TotalSize);
607   sys::swapByteOrder<uint32_t>(NumValueKinds);
608 }
609 
610 // The argument to this method is a vector of cutoff percentages and the return
611 // value is a vector of (Cutoff, MinBlockCount, NumBlocks) triplets.
612 void ProfileSummary::computeDetailedSummary() {
613   if (DetailedSummaryCutoffs.empty())
614     return;
615   auto Iter = CountFrequencies.begin();
616   auto End = CountFrequencies.end();
617   std::sort(DetailedSummaryCutoffs.begin(), DetailedSummaryCutoffs.end());
618 
619   uint32_t BlocksSeen = 0;
620   uint64_t CurrSum = 0, Count;
621 
622   for (uint32_t Cutoff : DetailedSummaryCutoffs) {
623     assert(Cutoff <= 999999);
624     APInt Temp(128, TotalCount);
625     APInt N(128, Cutoff);
626     APInt D(128, ProfileSummary::Scale);
627     Temp *= N;
628     Temp = Temp.sdiv(D);
629     uint64_t DesiredCount = Temp.getZExtValue();
630     assert(DesiredCount <= TotalCount);
631     while (CurrSum < DesiredCount && Iter != End) {
632       Count = Iter->first;
633       uint32_t Freq = Iter->second;
634       CurrSum += (Count * Freq);
635       BlocksSeen += Freq;
636       Iter++;
637     }
638     assert(CurrSum >= DesiredCount);
639     ProfileSummaryEntry PSE = {Cutoff, Count, BlocksSeen};
640     DetailedSummary.push_back(PSE);
641   }
642 }
643 
644 } // end namespace llvm
645