InstrProfWriter.cpp revision 360784 
1//===- InstrProfWriter.cpp - Instrumented profiling writer ----------------===//
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 support for writing profiling data for clang's
10// instrumentation based PGO and coverage.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/ProfileData/InstrProfWriter.h"
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/IR/ProfileSummary.h"
18#include "llvm/ProfileData/InstrProf.h"
19#include "llvm/ProfileData/ProfileCommon.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/EndianStream.h"
22#include "llvm/Support/Error.h"
23#include "llvm/Support/MemoryBuffer.h"
24#include "llvm/Support/OnDiskHashTable.h"
25#include "llvm/Support/raw_ostream.h"
26#include <algorithm>
27#include <cstdint>
28#include <memory>
29#include <string>
30#include <tuple>
31#include <utility>
32#include <vector>
33
34using namespace llvm;
35
36// A struct to define how the data stream should be patched. For Indexed
37// profiling, only uint64_t data type is needed.
38struct PatchItem {
39  uint64_t Pos; // Where to patch.
40  uint64_t *D;  // Pointer to an array of source data.
41  int N;        // Number of elements in \c D array.
42};
43
44namespace llvm {
45
46// A wrapper class to abstract writer stream with support of bytes
47// back patching.
48class ProfOStream {
49public:
50  ProfOStream(raw_fd_ostream &FD)
51      : IsFDOStream(true), OS(FD), LE(FD, support::little) {}
52  ProfOStream(raw_string_ostream &STR)
53      : IsFDOStream(false), OS(STR), LE(STR, support::little) {}
54
55  uint64_t tell() { return OS.tell(); }
56  void write(uint64_t V) { LE.write<uint64_t>(V); }
57
58  // \c patch can only be called when all data is written and flushed.
59  // For raw_string_ostream, the patch is done on the target string
60  // directly and it won't be reflected in the stream's internal buffer.
61  void patch(PatchItem *P, int NItems) {
62    using namespace support;
63
64    if (IsFDOStream) {
65      raw_fd_ostream &FDOStream = static_cast<raw_fd_ostream &>(OS);
66      for (int K = 0; K < NItems; K++) {
67        FDOStream.seek(P[K].Pos);
68        for (int I = 0; I < P[K].N; I++)
69          write(P[K].D[I]);
70      }
71    } else {
72      raw_string_ostream &SOStream = static_cast<raw_string_ostream &>(OS);
73      std::string &Data = SOStream.str(); // with flush
74      for (int K = 0; K < NItems; K++) {
75        for (int I = 0; I < P[K].N; I++) {
76          uint64_t Bytes = endian::byte_swap<uint64_t, little>(P[K].D[I]);
77          Data.replace(P[K].Pos + I * sizeof(uint64_t), sizeof(uint64_t),
78                       (const char *)&Bytes, sizeof(uint64_t));
79        }
80      }
81    }
82  }
83
84  // If \c OS is an instance of \c raw_fd_ostream, this field will be
85  // true. Otherwise, \c OS will be an raw_string_ostream.
86  bool IsFDOStream;
87  raw_ostream &OS;
88  support::endian::Writer LE;
89};
90
91class InstrProfRecordWriterTrait {
92public:
93  using key_type = StringRef;
94  using key_type_ref = StringRef;
95
96  using data_type = const InstrProfWriter::ProfilingData *const;
97  using data_type_ref = const InstrProfWriter::ProfilingData *const;
98
99  using hash_value_type = uint64_t;
100  using offset_type = uint64_t;
101
102  support::endianness ValueProfDataEndianness = support::little;
103  InstrProfSummaryBuilder *SummaryBuilder;
104  InstrProfSummaryBuilder *CSSummaryBuilder;
105
106  InstrProfRecordWriterTrait() = default;
107
108  static hash_value_type ComputeHash(key_type_ref K) {
109    return IndexedInstrProf::ComputeHash(K);
110  }
111
112  static std::pair<offset_type, offset_type>
113  EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
114    using namespace support;
115
116    endian::Writer LE(Out, little);
117
118    offset_type N = K.size();
119    LE.write<offset_type>(N);
120
121    offset_type M = 0;
122    for (const auto &ProfileData : *V) {
123      const InstrProfRecord &ProfRecord = ProfileData.second;
124      M += sizeof(uint64_t); // The function hash
125      M += sizeof(uint64_t); // The size of the Counts vector
126      M += ProfRecord.Counts.size() * sizeof(uint64_t);
127
128      // Value data
129      M += ValueProfData::getSize(ProfileData.second);
130    }
131    LE.write<offset_type>(M);
132
133    return std::make_pair(N, M);
134  }
135
136  void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N) {
137    Out.write(K.data(), N);
138  }
139
140  void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V, offset_type) {
141    using namespace support;
142
143    endian::Writer LE(Out, little);
144    for (const auto &ProfileData : *V) {
145      const InstrProfRecord &ProfRecord = ProfileData.second;
146      if (NamedInstrProfRecord::hasCSFlagInHash(ProfileData.first))
147        CSSummaryBuilder->addRecord(ProfRecord);
148      else
149        SummaryBuilder->addRecord(ProfRecord);
150
151      LE.write<uint64_t>(ProfileData.first); // Function hash
152      LE.write<uint64_t>(ProfRecord.Counts.size());
153      for (uint64_t I : ProfRecord.Counts)
154        LE.write<uint64_t>(I);
155
156      // Write value data
157      std::unique_ptr<ValueProfData> VDataPtr =
158          ValueProfData::serializeFrom(ProfileData.second);
159      uint32_t S = VDataPtr->getSize();
160      VDataPtr->swapBytesFromHost(ValueProfDataEndianness);
161      Out.write((const char *)VDataPtr.get(), S);
162    }
163  }
164};
165
166} // end namespace llvm
167
168InstrProfWriter::InstrProfWriter(bool Sparse)
169    : Sparse(Sparse), InfoObj(new InstrProfRecordWriterTrait()) {}
170
171InstrProfWriter::~InstrProfWriter() { delete InfoObj; }
172
173// Internal interface for testing purpose only.
174void InstrProfWriter::setValueProfDataEndianness(
175    support::endianness Endianness) {
176  InfoObj->ValueProfDataEndianness = Endianness;
177}
178
179void InstrProfWriter::setOutputSparse(bool Sparse) {
180  this->Sparse = Sparse;
181}
182
183void InstrProfWriter::addRecord(NamedInstrProfRecord &&I, uint64_t Weight,
184                                function_ref<void(Error)> Warn) {
185  auto Name = I.Name;
186  auto Hash = I.Hash;
187  addRecord(Name, Hash, std::move(I), Weight, Warn);
188}
189
190void InstrProfWriter::overlapRecord(NamedInstrProfRecord &&Other,
191                                    OverlapStats &Overlap,
192                                    OverlapStats &FuncLevelOverlap,
193                                    const OverlapFuncFilters &FuncFilter) {
194  auto Name = Other.Name;
195  auto Hash = Other.Hash;
196  Other.accumulateCounts(FuncLevelOverlap.Test);
197  if (FunctionData.find(Name) == FunctionData.end()) {
198    Overlap.addOneUnique(FuncLevelOverlap.Test);
199    return;
200  }
201  if (FuncLevelOverlap.Test.CountSum < 1.0f) {
202    Overlap.Overlap.NumEntries += 1;
203    return;
204  }
205  auto &ProfileDataMap = FunctionData[Name];
206  bool NewFunc;
207  ProfilingData::iterator Where;
208  std::tie(Where, NewFunc) =
209      ProfileDataMap.insert(std::make_pair(Hash, InstrProfRecord()));
210  if (NewFunc) {
211    Overlap.addOneMismatch(FuncLevelOverlap.Test);
212    return;
213  }
214  InstrProfRecord &Dest = Where->second;
215
216  uint64_t ValueCutoff = FuncFilter.ValueCutoff;
217  if (!FuncFilter.NameFilter.empty() &&
218      Name.find(FuncFilter.NameFilter) != Name.npos)
219    ValueCutoff = 0;
220
221  Dest.overlap(Other, Overlap, FuncLevelOverlap, ValueCutoff);
222}
223
224void InstrProfWriter::addRecord(StringRef Name, uint64_t Hash,
225                                InstrProfRecord &&I, uint64_t Weight,
226                                function_ref<void(Error)> Warn) {
227  auto &ProfileDataMap = FunctionData[Name];
228
229  bool NewFunc;
230  ProfilingData::iterator Where;
231  std::tie(Where, NewFunc) =
232      ProfileDataMap.insert(std::make_pair(Hash, InstrProfRecord()));
233  InstrProfRecord &Dest = Where->second;
234
235  auto MapWarn = [&](instrprof_error E) {
236    Warn(make_error<InstrProfError>(E));
237  };
238
239  if (NewFunc) {
240    // We've never seen a function with this name and hash, add it.
241    Dest = std::move(I);
242    if (Weight > 1)
243      Dest.scale(Weight, MapWarn);
244  } else {
245    // We're updating a function we've seen before.
246    Dest.merge(I, Weight, MapWarn);
247  }
248
249  Dest.sortValueData();
250}
251
252void InstrProfWriter::mergeRecordsFromWriter(InstrProfWriter &&IPW,
253                                             function_ref<void(Error)> Warn) {
254  for (auto &I : IPW.FunctionData)
255    for (auto &Func : I.getValue())
256      addRecord(I.getKey(), Func.first, std::move(Func.second), 1, Warn);
257}
258
259bool InstrProfWriter::shouldEncodeData(const ProfilingData &PD) {
260  if (!Sparse)
261    return true;
262  for (const auto &Func : PD) {
263    const InstrProfRecord &IPR = Func.second;
264    if (llvm::any_of(IPR.Counts, [](uint64_t Count) { return Count > 0; }))
265      return true;
266  }
267  return false;
268}
269
270static void setSummary(IndexedInstrProf::Summary *TheSummary,
271                       ProfileSummary &PS) {
272  using namespace IndexedInstrProf;
273
274  std::vector<ProfileSummaryEntry> &Res = PS.getDetailedSummary();
275  TheSummary->NumSummaryFields = Summary::NumKinds;
276  TheSummary->NumCutoffEntries = Res.size();
277  TheSummary->set(Summary::MaxFunctionCount, PS.getMaxFunctionCount());
278  TheSummary->set(Summary::MaxBlockCount, PS.getMaxCount());
279  TheSummary->set(Summary::MaxInternalBlockCount, PS.getMaxInternalCount());
280  TheSummary->set(Summary::TotalBlockCount, PS.getTotalCount());
281  TheSummary->set(Summary::TotalNumBlocks, PS.getNumCounts());
282  TheSummary->set(Summary::TotalNumFunctions, PS.getNumFunctions());
283  for (unsigned I = 0; I < Res.size(); I++)
284    TheSummary->setEntry(I, Res[I]);
285}
286
287void InstrProfWriter::writeImpl(ProfOStream &OS) {
288  using namespace IndexedInstrProf;
289
290  OnDiskChainedHashTableGenerator<InstrProfRecordWriterTrait> Generator;
291
292  InstrProfSummaryBuilder ISB(ProfileSummaryBuilder::DefaultCutoffs);
293  InfoObj->SummaryBuilder = &ISB;
294  InstrProfSummaryBuilder CSISB(ProfileSummaryBuilder::DefaultCutoffs);
295  InfoObj->CSSummaryBuilder = &CSISB;
296
297  // Populate the hash table generator.
298  for (const auto &I : FunctionData)
299    if (shouldEncodeData(I.getValue()))
300      Generator.insert(I.getKey(), &I.getValue());
301  // Write the header.
302  IndexedInstrProf::Header Header;
303  Header.Magic = IndexedInstrProf::Magic;
304  Header.Version = IndexedInstrProf::ProfVersion::CurrentVersion;
305  if (ProfileKind == PF_IRLevel)
306    Header.Version |= VARIANT_MASK_IR_PROF;
307  if (ProfileKind == PF_IRLevelWithCS) {
308    Header.Version |= VARIANT_MASK_IR_PROF;
309    Header.Version |= VARIANT_MASK_CSIR_PROF;
310  }
311  Header.Unused = 0;
312  Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
313  Header.HashOffset = 0;
314  int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t);
315
316  // Only write out all the fields except 'HashOffset'. We need
317  // to remember the offset of that field to allow back patching
318  // later.
319  for (int I = 0; I < N - 1; I++)
320    OS.write(reinterpret_cast<uint64_t *>(&Header)[I]);
321
322  // Save the location of Header.HashOffset field in \c OS.
323  uint64_t HashTableStartFieldOffset = OS.tell();
324  // Reserve the space for HashOffset field.
325  OS.write(0);
326
327  // Reserve space to write profile summary data.
328  uint32_t NumEntries = ProfileSummaryBuilder::DefaultCutoffs.size();
329  uint32_t SummarySize = Summary::getSize(Summary::NumKinds, NumEntries);
330  // Remember the summary offset.
331  uint64_t SummaryOffset = OS.tell();
332  for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
333    OS.write(0);
334  uint64_t CSSummaryOffset = 0;
335  uint64_t CSSummarySize = 0;
336  if (ProfileKind == PF_IRLevelWithCS) {
337    CSSummaryOffset = OS.tell();
338    CSSummarySize = SummarySize / sizeof(uint64_t);
339    for (unsigned I = 0; I < CSSummarySize; I++)
340      OS.write(0);
341  }
342
343  // Write the hash table.
344  uint64_t HashTableStart = Generator.Emit(OS.OS, *InfoObj);
345
346  // Allocate space for data to be serialized out.
347  std::unique_ptr<IndexedInstrProf::Summary> TheSummary =
348      IndexedInstrProf::allocSummary(SummarySize);
349  // Compute the Summary and copy the data to the data
350  // structure to be serialized out (to disk or buffer).
351  std::unique_ptr<ProfileSummary> PS = ISB.getSummary();
352  setSummary(TheSummary.get(), *PS);
353  InfoObj->SummaryBuilder = nullptr;
354
355  // For Context Sensitive summary.
356  std::unique_ptr<IndexedInstrProf::Summary> TheCSSummary = nullptr;
357  if (ProfileKind == PF_IRLevelWithCS) {
358    TheCSSummary = IndexedInstrProf::allocSummary(SummarySize);
359    std::unique_ptr<ProfileSummary> CSPS = CSISB.getSummary();
360    setSummary(TheCSSummary.get(), *CSPS);
361  }
362  InfoObj->CSSummaryBuilder = nullptr;
363
364  // Now do the final patch:
365  PatchItem PatchItems[] = {
366      // Patch the Header.HashOffset field.
367      {HashTableStartFieldOffset, &HashTableStart, 1},
368      // Patch the summary data.
369      {SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
370       (int)(SummarySize / sizeof(uint64_t))},
371      {CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
372       (int)CSSummarySize}};
373
374  OS.patch(PatchItems, sizeof(PatchItems) / sizeof(*PatchItems));
375}
376
377void InstrProfWriter::write(raw_fd_ostream &OS) {
378  // Write the hash table.
379  ProfOStream POS(OS);
380  writeImpl(POS);
381}
382
383std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() {
384  std::string Data;
385  raw_string_ostream OS(Data);
386  ProfOStream POS(OS);
387  // Write the hash table.
388  writeImpl(POS);
389  // Return this in an aligned memory buffer.
390  return MemoryBuffer::getMemBufferCopy(Data);
391}
392
393static const char *ValueProfKindStr[] = {
394#define VALUE_PROF_KIND(Enumerator, Value, Descr) #Enumerator,
395#include "llvm/ProfileData/InstrProfData.inc"
396};
397
398void InstrProfWriter::writeRecordInText(StringRef Name, uint64_t Hash,
399                                        const InstrProfRecord &Func,
400                                        InstrProfSymtab &Symtab,
401                                        raw_fd_ostream &OS) {
402  OS << Name << "\n";
403  OS << "# Func Hash:\n" << Hash << "\n";
404  OS << "# Num Counters:\n" << Func.Counts.size() << "\n";
405  OS << "# Counter Values:\n";
406  for (uint64_t Count : Func.Counts)
407    OS << Count << "\n";
408
409  uint32_t NumValueKinds = Func.getNumValueKinds();
410  if (!NumValueKinds) {
411    OS << "\n";
412    return;
413  }
414
415  OS << "# Num Value Kinds:\n" << Func.getNumValueKinds() << "\n";
416  for (uint32_t VK = 0; VK < IPVK_Last + 1; VK++) {
417    uint32_t NS = Func.getNumValueSites(VK);
418    if (!NS)
419      continue;
420    OS << "# ValueKind = " << ValueProfKindStr[VK] << ":\n" << VK << "\n";
421    OS << "# NumValueSites:\n" << NS << "\n";
422    for (uint32_t S = 0; S < NS; S++) {
423      uint32_t ND = Func.getNumValueDataForSite(VK, S);
424      OS << ND << "\n";
425      std::unique_ptr<InstrProfValueData[]> VD = Func.getValueForSite(VK, S);
426      for (uint32_t I = 0; I < ND; I++) {
427        if (VK == IPVK_IndirectCallTarget)
428          OS << Symtab.getFuncNameOrExternalSymbol(VD[I].Value) << ":"
429             << VD[I].Count << "\n";
430        else
431          OS << VD[I].Value << ":" << VD[I].Count << "\n";
432      }
433    }
434  }
435
436  OS << "\n";
437}
438
439Error InstrProfWriter::writeText(raw_fd_ostream &OS) {
440  if (ProfileKind == PF_IRLevel)
441    OS << "# IR level Instrumentation Flag\n:ir\n";
442  else if (ProfileKind == PF_IRLevelWithCS)
443    OS << "# CSIR level Instrumentation Flag\n:csir\n";
444  InstrProfSymtab Symtab;
445
446  using FuncPair = detail::DenseMapPair<uint64_t, InstrProfRecord>;
447  using RecordType = std::pair<StringRef, FuncPair>;
448  SmallVector<RecordType, 4> OrderedFuncData;
449
450  for (const auto &I : FunctionData) {
451    if (shouldEncodeData(I.getValue())) {
452      if (Error E = Symtab.addFuncName(I.getKey()))
453        return E;
454      for (const auto &Func : I.getValue())
455        OrderedFuncData.push_back(std::make_pair(I.getKey(), Func));
456    }
457  }
458
459  llvm::sort(OrderedFuncData, [](const RecordType &A, const RecordType &B) {
460    return std::tie(A.first, A.second.first) <
461           std::tie(B.first, B.second.first);
462  });
463
464  for (const auto &record : OrderedFuncData) {
465    const StringRef &Name = record.first;
466    const FuncPair &Func = record.second;
467    writeRecordInText(Name, Func.first, Func.second, Symtab, OS);
468  }
469
470  return Error::success();
471}
472