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 }
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) {
220   std::vector<std::string> NameStrs;
221   for (auto *NameVar : NameVars) {
222     NameStrs.push_back(getPGOFuncNameInitializer(NameVar));
223   }
224   return collectPGOFuncNameStrings(NameStrs, zlib::isAvailable(), Result);
225 }
226 
227 int readPGOFuncNameStrings(StringRef NameStrings, InstrProfSymtab &Symtab) {
228   const uint8_t *P = reinterpret_cast<const uint8_t *>(NameStrings.data());
229   const uint8_t *EndP = reinterpret_cast<const uint8_t *>(NameStrings.data() +
230                                                           NameStrings.size());
231   while (P < EndP) {
232     uint32_t N;
233     uint64_t UncompressedSize = decodeULEB128(P, &N);
234     P += N;
235     uint64_t CompressedSize = decodeULEB128(P, &N);
236     P += N;
237     bool isCompressed = (CompressedSize != 0);
238     SmallString<128> UncompressedNameStrings;
239     StringRef NameStrings;
240     if (isCompressed) {
241       StringRef CompressedNameStrings(reinterpret_cast<const char *>(P),
242                                       CompressedSize);
243       if (zlib::uncompress(CompressedNameStrings, UncompressedNameStrings,
244                            UncompressedSize) != zlib::StatusOK)
245         return 1;
246       P += CompressedSize;
247       NameStrings = StringRef(UncompressedNameStrings.data(),
248                               UncompressedNameStrings.size());
249     } else {
250       NameStrings =
251           StringRef(reinterpret_cast<const char *>(P), UncompressedSize);
252       P += UncompressedSize;
253     }
254     // Now parse the name strings.
255     SmallVector<StringRef, 0> Names;
256     NameStrings.split(Names, ' ');
257     for (StringRef &Name : Names)
258       Symtab.addFuncName(Name);
259 
260     while (P < EndP && *P == 0)
261       P++;
262   }
263   Symtab.finalizeSymtab();
264   return 0;
265 }
266 
267 instrprof_error InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord &Input,
268                                                 uint64_t Weight) {
269   this->sortByTargetValues();
270   Input.sortByTargetValues();
271   auto I = ValueData.begin();
272   auto IE = ValueData.end();
273   instrprof_error Result = instrprof_error::success;
274   for (auto J = Input.ValueData.begin(), JE = Input.ValueData.end(); J != JE;
275        ++J) {
276     while (I != IE && I->Value < J->Value)
277       ++I;
278     if (I != IE && I->Value == J->Value) {
279       bool Overflowed;
280       I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count, &Overflowed);
281       if (Overflowed)
282         Result = instrprof_error::counter_overflow;
283       ++I;
284       continue;
285     }
286     ValueData.insert(I, *J);
287   }
288   return Result;
289 }
290 
291 instrprof_error InstrProfValueSiteRecord::scale(uint64_t Weight) {
292   instrprof_error Result = instrprof_error::success;
293   for (auto I = ValueData.begin(), IE = ValueData.end(); I != IE; ++I) {
294     bool Overflowed;
295     I->Count = SaturatingMultiply(I->Count, Weight, &Overflowed);
296     if (Overflowed)
297       Result = instrprof_error::counter_overflow;
298   }
299   return Result;
300 }
301 
302 // Merge Value Profile data from Src record to this record for ValueKind.
303 // Scale merged value counts by \p Weight.
304 instrprof_error InstrProfRecord::mergeValueProfData(uint32_t ValueKind,
305                                                     InstrProfRecord &Src,
306                                                     uint64_t Weight) {
307   uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
308   uint32_t OtherNumValueSites = Src.getNumValueSites(ValueKind);
309   if (ThisNumValueSites != OtherNumValueSites)
310     return instrprof_error::value_site_count_mismatch;
311   std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
312       getValueSitesForKind(ValueKind);
313   std::vector<InstrProfValueSiteRecord> &OtherSiteRecords =
314       Src.getValueSitesForKind(ValueKind);
315   instrprof_error Result = instrprof_error::success;
316   for (uint32_t I = 0; I < ThisNumValueSites; I++)
317     MergeResult(Result, ThisSiteRecords[I].merge(OtherSiteRecords[I], Weight));
318   return Result;
319 }
320 
321 instrprof_error InstrProfRecord::merge(InstrProfRecord &Other,
322                                        uint64_t Weight) {
323   // If the number of counters doesn't match we either have bad data
324   // or a hash collision.
325   if (Counts.size() != Other.Counts.size())
326     return instrprof_error::count_mismatch;
327 
328   instrprof_error Result = instrprof_error::success;
329 
330   for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
331     bool Overflowed;
332     Counts[I] =
333         SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I], &Overflowed);
334     if (Overflowed)
335       Result = instrprof_error::counter_overflow;
336   }
337 
338   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
339     MergeResult(Result, mergeValueProfData(Kind, Other, Weight));
340 
341   return Result;
342 }
343 
344 instrprof_error InstrProfRecord::scaleValueProfData(uint32_t ValueKind,
345                                                     uint64_t Weight) {
346   uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
347   std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
348       getValueSitesForKind(ValueKind);
349   instrprof_error Result = instrprof_error::success;
350   for (uint32_t I = 0; I < ThisNumValueSites; I++)
351     MergeResult(Result, ThisSiteRecords[I].scale(Weight));
352   return Result;
353 }
354 
355 instrprof_error InstrProfRecord::scale(uint64_t Weight) {
356   instrprof_error Result = instrprof_error::success;
357   for (auto &Count : this->Counts) {
358     bool Overflowed;
359     Count = SaturatingMultiply(Count, Weight, &Overflowed);
360     if (Overflowed && Result == instrprof_error::success) {
361       Result = instrprof_error::counter_overflow;
362     }
363   }
364   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
365     MergeResult(Result, scaleValueProfData(Kind, Weight));
366 
367   return Result;
368 }
369 
370 // Map indirect call target name hash to name string.
371 uint64_t InstrProfRecord::remapValue(uint64_t Value, uint32_t ValueKind,
372                                      ValueMapType *ValueMap) {
373   if (!ValueMap)
374     return Value;
375   switch (ValueKind) {
376   case IPVK_IndirectCallTarget: {
377     auto Result =
378         std::lower_bound(ValueMap->begin(), ValueMap->end(), Value,
379                          [](const std::pair<uint64_t, uint64_t> &LHS,
380                             uint64_t RHS) { return LHS.first < RHS; });
381     if (Result != ValueMap->end())
382       Value = (uint64_t)Result->second;
383     break;
384   }
385   }
386   return Value;
387 }
388 
389 void InstrProfRecord::addValueData(uint32_t ValueKind, uint32_t Site,
390                                    InstrProfValueData *VData, uint32_t N,
391                                    ValueMapType *ValueMap) {
392   for (uint32_t I = 0; I < N; I++) {
393     VData[I].Value = remapValue(VData[I].Value, ValueKind, ValueMap);
394   }
395   std::vector<InstrProfValueSiteRecord> &ValueSites =
396       getValueSitesForKind(ValueKind);
397   if (N == 0)
398     ValueSites.push_back(InstrProfValueSiteRecord());
399   else
400     ValueSites.emplace_back(VData, VData + N);
401 }
402 
403 #define INSTR_PROF_COMMON_API_IMPL
404 #include "llvm/ProfileData/InstrProfData.inc"
405 
406 /*!
407  * \brief ValueProfRecordClosure Interface implementation for  InstrProfRecord
408  *  class. These C wrappers are used as adaptors so that C++ code can be
409  *  invoked as callbacks.
410  */
411 uint32_t getNumValueKindsInstrProf(const void *Record) {
412   return reinterpret_cast<const InstrProfRecord *>(Record)->getNumValueKinds();
413 }
414 
415 uint32_t getNumValueSitesInstrProf(const void *Record, uint32_t VKind) {
416   return reinterpret_cast<const InstrProfRecord *>(Record)
417       ->getNumValueSites(VKind);
418 }
419 
420 uint32_t getNumValueDataInstrProf(const void *Record, uint32_t VKind) {
421   return reinterpret_cast<const InstrProfRecord *>(Record)
422       ->getNumValueData(VKind);
423 }
424 
425 uint32_t getNumValueDataForSiteInstrProf(const void *R, uint32_t VK,
426                                          uint32_t S) {
427   return reinterpret_cast<const InstrProfRecord *>(R)
428       ->getNumValueDataForSite(VK, S);
429 }
430 
431 void getValueForSiteInstrProf(const void *R, InstrProfValueData *Dst,
432                               uint32_t K, uint32_t S,
433                               uint64_t (*Mapper)(uint32_t, uint64_t)) {
434   return reinterpret_cast<const InstrProfRecord *>(R)->getValueForSite(
435       Dst, K, S, Mapper);
436 }
437 
438 ValueProfData *allocValueProfDataInstrProf(size_t TotalSizeInBytes) {
439   ValueProfData *VD =
440       (ValueProfData *)(new (::operator new(TotalSizeInBytes)) ValueProfData());
441   memset(VD, 0, TotalSizeInBytes);
442   return VD;
443 }
444 
445 static ValueProfRecordClosure InstrProfRecordClosure = {
446     0,
447     getNumValueKindsInstrProf,
448     getNumValueSitesInstrProf,
449     getNumValueDataInstrProf,
450     getNumValueDataForSiteInstrProf,
451     0,
452     getValueForSiteInstrProf,
453     allocValueProfDataInstrProf};
454 
455 // Wrapper implementation using the closure mechanism.
456 uint32_t ValueProfData::getSize(const InstrProfRecord &Record) {
457   InstrProfRecordClosure.Record = &Record;
458   return getValueProfDataSize(&InstrProfRecordClosure);
459 }
460 
461 // Wrapper implementation using the closure mechanism.
462 std::unique_ptr<ValueProfData>
463 ValueProfData::serializeFrom(const InstrProfRecord &Record) {
464   InstrProfRecordClosure.Record = &Record;
465 
466   std::unique_ptr<ValueProfData> VPD(
467       serializeValueProfDataFrom(&InstrProfRecordClosure, nullptr));
468   return VPD;
469 }
470 
471 void ValueProfRecord::deserializeTo(InstrProfRecord &Record,
472                                     InstrProfRecord::ValueMapType *VMap) {
473   Record.reserveSites(Kind, NumValueSites);
474 
475   InstrProfValueData *ValueData = getValueProfRecordValueData(this);
476   for (uint64_t VSite = 0; VSite < NumValueSites; ++VSite) {
477     uint8_t ValueDataCount = this->SiteCountArray[VSite];
478     Record.addValueData(Kind, VSite, ValueData, ValueDataCount, VMap);
479     ValueData += ValueDataCount;
480   }
481 }
482 
483 // For writing/serializing,  Old is the host endianness, and  New is
484 // byte order intended on disk. For Reading/deserialization, Old
485 // is the on-disk source endianness, and New is the host endianness.
486 void ValueProfRecord::swapBytes(support::endianness Old,
487                                 support::endianness New) {
488   using namespace support;
489   if (Old == New)
490     return;
491 
492   if (getHostEndianness() != Old) {
493     sys::swapByteOrder<uint32_t>(NumValueSites);
494     sys::swapByteOrder<uint32_t>(Kind);
495   }
496   uint32_t ND = getValueProfRecordNumValueData(this);
497   InstrProfValueData *VD = getValueProfRecordValueData(this);
498 
499   // No need to swap byte array: SiteCountArrray.
500   for (uint32_t I = 0; I < ND; I++) {
501     sys::swapByteOrder<uint64_t>(VD[I].Value);
502     sys::swapByteOrder<uint64_t>(VD[I].Count);
503   }
504   if (getHostEndianness() == Old) {
505     sys::swapByteOrder<uint32_t>(NumValueSites);
506     sys::swapByteOrder<uint32_t>(Kind);
507   }
508 }
509 
510 void ValueProfData::deserializeTo(InstrProfRecord &Record,
511                                   InstrProfRecord::ValueMapType *VMap) {
512   if (NumValueKinds == 0)
513     return;
514 
515   ValueProfRecord *VR = getFirstValueProfRecord(this);
516   for (uint32_t K = 0; K < NumValueKinds; K++) {
517     VR->deserializeTo(Record, VMap);
518     VR = getValueProfRecordNext(VR);
519   }
520 }
521 
522 template <class T>
523 static T swapToHostOrder(const unsigned char *&D, support::endianness Orig) {
524   using namespace support;
525   if (Orig == little)
526     return endian::readNext<T, little, unaligned>(D);
527   else
528     return endian::readNext<T, big, unaligned>(D);
529 }
530 
531 static std::unique_ptr<ValueProfData> allocValueProfData(uint32_t TotalSize) {
532   return std::unique_ptr<ValueProfData>(new (::operator new(TotalSize))
533                                             ValueProfData());
534 }
535 
536 instrprof_error ValueProfData::checkIntegrity() {
537   if (NumValueKinds > IPVK_Last + 1)
538     return instrprof_error::malformed;
539   // Total size needs to be mulltiple of quadword size.
540   if (TotalSize % sizeof(uint64_t))
541     return instrprof_error::malformed;
542 
543   ValueProfRecord *VR = getFirstValueProfRecord(this);
544   for (uint32_t K = 0; K < this->NumValueKinds; K++) {
545     if (VR->Kind > IPVK_Last)
546       return instrprof_error::malformed;
547     VR = getValueProfRecordNext(VR);
548     if ((char *)VR - (char *)this > (ptrdiff_t)TotalSize)
549       return instrprof_error::malformed;
550   }
551   return instrprof_error::success;
552 }
553 
554 ErrorOr<std::unique_ptr<ValueProfData>>
555 ValueProfData::getValueProfData(const unsigned char *D,
556                                 const unsigned char *const BufferEnd,
557                                 support::endianness Endianness) {
558   using namespace support;
559   if (D + sizeof(ValueProfData) > BufferEnd)
560     return instrprof_error::truncated;
561 
562   const unsigned char *Header = D;
563   uint32_t TotalSize = swapToHostOrder<uint32_t>(Header, Endianness);
564   if (D + TotalSize > BufferEnd)
565     return instrprof_error::too_large;
566 
567   std::unique_ptr<ValueProfData> VPD = allocValueProfData(TotalSize);
568   memcpy(VPD.get(), D, TotalSize);
569   // Byte swap.
570   VPD->swapBytesToHost(Endianness);
571 
572   instrprof_error EC = VPD->checkIntegrity();
573   if (EC != instrprof_error::success)
574     return EC;
575 
576   return std::move(VPD);
577 }
578 
579 void ValueProfData::swapBytesToHost(support::endianness Endianness) {
580   using namespace support;
581   if (Endianness == getHostEndianness())
582     return;
583 
584   sys::swapByteOrder<uint32_t>(TotalSize);
585   sys::swapByteOrder<uint32_t>(NumValueKinds);
586 
587   ValueProfRecord *VR = getFirstValueProfRecord(this);
588   for (uint32_t K = 0; K < NumValueKinds; K++) {
589     VR->swapBytes(Endianness, getHostEndianness());
590     VR = getValueProfRecordNext(VR);
591   }
592 }
593 
594 void ValueProfData::swapBytesFromHost(support::endianness Endianness) {
595   using namespace support;
596   if (Endianness == getHostEndianness())
597     return;
598 
599   ValueProfRecord *VR = getFirstValueProfRecord(this);
600   for (uint32_t K = 0; K < NumValueKinds; K++) {
601     ValueProfRecord *NVR = getValueProfRecordNext(VR);
602     VR->swapBytes(getHostEndianness(), Endianness);
603     VR = NVR;
604   }
605   sys::swapByteOrder<uint32_t>(TotalSize);
606   sys::swapByteOrder<uint32_t>(NumValueKinds);
607 }
608 
609 // The argument to this method is a vector of cutoff percentages and the return
610 // value is a vector of (Cutoff, MinBlockCount, NumBlocks) triplets.
611 void ProfileSummary::computeDetailedSummary() {
612   if (DetailedSummaryCutoffs.empty())
613     return;
614   auto Iter = CountFrequencies.begin();
615   auto End = CountFrequencies.end();
616   std::sort(DetailedSummaryCutoffs.begin(), DetailedSummaryCutoffs.end());
617 
618   uint32_t BlocksSeen = 0;
619   uint64_t CurrSum = 0, Count;
620 
621   for (uint32_t Cutoff : DetailedSummaryCutoffs) {
622     assert(Cutoff <= 999999);
623     APInt Temp(128, TotalCount);
624     APInt N(128, Cutoff);
625     APInt D(128, ProfileSummary::Scale);
626     Temp *= N;
627     Temp = Temp.sdiv(D);
628     uint64_t DesiredCount = Temp.getZExtValue();
629     assert(DesiredCount <= TotalCount);
630     while (CurrSum < DesiredCount && Iter != End) {
631       Count = Iter->first;
632       uint32_t Freq = Iter->second;
633       CurrSum += (Count * Freq);
634       BlocksSeen += Freq;
635       Iter++;
636     }
637     assert(CurrSum >= DesiredCount);
638     ProfileSummaryEntry PSE = {Cutoff, Count, BlocksSeen};
639     DetailedSummary.push_back(PSE);
640   }
641   return;
642 }
643 
644 }
645