xref: /freebsd/contrib/llvm-project/llvm/lib/ProfileData/InstrProfReader.cpp (revision 833a452e9f082a7982a31c21f0da437dbbe0a39d) 
1 //===- InstrProfReader.cpp - Instrumented profiling reader ----------------===//
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 reading profiling data for clang's
10 // instrumentation based PGO and coverage.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/ProfileData/InstrProfReader.h"
15 #include "llvm/ADT/ArrayRef.h"
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/IR/ProfileSummary.h"
21 #include "llvm/ProfileData/InstrProf.h"
22 #include "llvm/ProfileData/ProfileCommon.h"
23 #include "llvm/Support/Endian.h"
24 #include "llvm/Support/Error.h"
25 #include "llvm/Support/ErrorOr.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/SwapByteOrder.h"
28 #include "llvm/Support/SymbolRemappingReader.h"
29 #include <algorithm>
30 #include <cctype>
31 #include <cstddef>
32 #include <cstdint>
33 #include <limits>
34 #include <memory>
35 #include <system_error>
36 #include <utility>
37 #include <vector>
38 
39 using namespace llvm;
40 
41 static Expected<std::unique_ptr<MemoryBuffer>>
42 setupMemoryBuffer(const Twine &Path) {
43   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
44       MemoryBuffer::getFileOrSTDIN(Path, /*IsText=*/true);
45   if (std::error_code EC = BufferOrErr.getError())
46     return errorCodeToError(EC);
47   return std::move(BufferOrErr.get());
48 }
49 
50 static Error initializeReader(InstrProfReader &Reader) {
51   return Reader.readHeader();
52 }
53 
54 Expected<std::unique_ptr<InstrProfReader>>
55 InstrProfReader::create(const Twine &Path) {
56   // Set up the buffer to read.
57   auto BufferOrError = setupMemoryBuffer(Path);
58   if (Error E = BufferOrError.takeError())
59     return std::move(E);
60   return InstrProfReader::create(std::move(BufferOrError.get()));
61 }
62 
63 Expected<std::unique_ptr<InstrProfReader>>
64 InstrProfReader::create(std::unique_ptr<MemoryBuffer> Buffer) {
65   // Sanity check the buffer.
66   if (uint64_t(Buffer->getBufferSize()) > std::numeric_limits<uint64_t>::max())
67     return make_error<InstrProfError>(instrprof_error::too_large);
68 
69   if (Buffer->getBufferSize() == 0)
70     return make_error<InstrProfError>(instrprof_error::empty_raw_profile);
71 
72   std::unique_ptr<InstrProfReader> Result;
73   // Create the reader.
74   if (IndexedInstrProfReader::hasFormat(*Buffer))
75     Result.reset(new IndexedInstrProfReader(std::move(Buffer)));
76   else if (RawInstrProfReader64::hasFormat(*Buffer))
77     Result.reset(new RawInstrProfReader64(std::move(Buffer)));
78   else if (RawInstrProfReader32::hasFormat(*Buffer))
79     Result.reset(new RawInstrProfReader32(std::move(Buffer)));
80   else if (TextInstrProfReader::hasFormat(*Buffer))
81     Result.reset(new TextInstrProfReader(std::move(Buffer)));
82   else
83     return make_error<InstrProfError>(instrprof_error::unrecognized_format);
84 
85   // Initialize the reader and return the result.
86   if (Error E = initializeReader(*Result))
87     return std::move(E);
88 
89   return std::move(Result);
90 }
91 
92 Expected<std::unique_ptr<IndexedInstrProfReader>>
93 IndexedInstrProfReader::create(const Twine &Path, const Twine &RemappingPath) {
94   // Set up the buffer to read.
95   auto BufferOrError = setupMemoryBuffer(Path);
96   if (Error E = BufferOrError.takeError())
97     return std::move(E);
98 
99   // Set up the remapping buffer if requested.
100   std::unique_ptr<MemoryBuffer> RemappingBuffer;
101   std::string RemappingPathStr = RemappingPath.str();
102   if (!RemappingPathStr.empty()) {
103     auto RemappingBufferOrError = setupMemoryBuffer(RemappingPathStr);
104     if (Error E = RemappingBufferOrError.takeError())
105       return std::move(E);
106     RemappingBuffer = std::move(RemappingBufferOrError.get());
107   }
108 
109   return IndexedInstrProfReader::create(std::move(BufferOrError.get()),
110                                         std::move(RemappingBuffer));
111 }
112 
113 Expected<std::unique_ptr<IndexedInstrProfReader>>
114 IndexedInstrProfReader::create(std::unique_ptr<MemoryBuffer> Buffer,
115                                std::unique_ptr<MemoryBuffer> RemappingBuffer) {
116   // Sanity check the buffer.
117   if (uint64_t(Buffer->getBufferSize()) > std::numeric_limits<uint64_t>::max())
118     return make_error<InstrProfError>(instrprof_error::too_large);
119 
120   // Create the reader.
121   if (!IndexedInstrProfReader::hasFormat(*Buffer))
122     return make_error<InstrProfError>(instrprof_error::bad_magic);
123   auto Result = std::make_unique<IndexedInstrProfReader>(
124       std::move(Buffer), std::move(RemappingBuffer));
125 
126   // Initialize the reader and return the result.
127   if (Error E = initializeReader(*Result))
128     return std::move(E);
129 
130   return std::move(Result);
131 }
132 
133 void InstrProfIterator::Increment() {
134   if (auto E = Reader->readNextRecord(Record)) {
135     // Handle errors in the reader.
136     InstrProfError::take(std::move(E));
137     *this = InstrProfIterator();
138   }
139 }
140 
141 bool TextInstrProfReader::hasFormat(const MemoryBuffer &Buffer) {
142   // Verify that this really looks like plain ASCII text by checking a
143   // 'reasonable' number of characters (up to profile magic size).
144   size_t count = std::min(Buffer.getBufferSize(), sizeof(uint64_t));
145   StringRef buffer = Buffer.getBufferStart();
146   return count == 0 ||
147          std::all_of(buffer.begin(), buffer.begin() + count,
148                      [](char c) { return isPrint(c) || isSpace(c); });
149 }
150 
151 // Read the profile variant flag from the header: ":FE" means this is a FE
152 // generated profile. ":IR" means this is an IR level profile. Other strings
153 // with a leading ':' will be reported an error format.
154 Error TextInstrProfReader::readHeader() {
155   Symtab.reset(new InstrProfSymtab());
156   bool IsIRInstr = false;
157   bool IsEntryFirst = false;
158   bool IsCS = false;
159 
160   while (Line->startswith(":")) {
161     StringRef Str = Line->substr(1);
162     if (Str.equals_insensitive("ir"))
163       IsIRInstr = true;
164     else if (Str.equals_insensitive("fe"))
165       IsIRInstr = false;
166     else if (Str.equals_insensitive("csir")) {
167       IsIRInstr = true;
168       IsCS = true;
169     } else if (Str.equals_insensitive("entry_first"))
170       IsEntryFirst = true;
171     else if (Str.equals_insensitive("not_entry_first"))
172       IsEntryFirst = false;
173     else
174       return error(instrprof_error::bad_header);
175     ++Line;
176   }
177   IsIRLevelProfile = IsIRInstr;
178   InstrEntryBBEnabled = IsEntryFirst;
179   HasCSIRLevelProfile = IsCS;
180   return success();
181 }
182 
183 Error
184 TextInstrProfReader::readValueProfileData(InstrProfRecord &Record) {
185 
186 #define CHECK_LINE_END(Line)                                                   \
187   if (Line.is_at_end())                                                        \
188     return error(instrprof_error::truncated);
189 #define READ_NUM(Str, Dst)                                                     \
190   if ((Str).getAsInteger(10, (Dst)))                                           \
191     return error(instrprof_error::malformed);
192 #define VP_READ_ADVANCE(Val)                                                   \
193   CHECK_LINE_END(Line);                                                        \
194   uint32_t Val;                                                                \
195   READ_NUM((*Line), (Val));                                                    \
196   Line++;
197 
198   if (Line.is_at_end())
199     return success();
200 
201   uint32_t NumValueKinds;
202   if (Line->getAsInteger(10, NumValueKinds)) {
203     // No value profile data
204     return success();
205   }
206   if (NumValueKinds == 0 || NumValueKinds > IPVK_Last + 1)
207     return error(instrprof_error::malformed);
208   Line++;
209 
210   for (uint32_t VK = 0; VK < NumValueKinds; VK++) {
211     VP_READ_ADVANCE(ValueKind);
212     if (ValueKind > IPVK_Last)
213       return error(instrprof_error::malformed);
214     VP_READ_ADVANCE(NumValueSites);
215     if (!NumValueSites)
216       continue;
217 
218     Record.reserveSites(VK, NumValueSites);
219     for (uint32_t S = 0; S < NumValueSites; S++) {
220       VP_READ_ADVANCE(NumValueData);
221 
222       std::vector<InstrProfValueData> CurrentValues;
223       for (uint32_t V = 0; V < NumValueData; V++) {
224         CHECK_LINE_END(Line);
225         std::pair<StringRef, StringRef> VD = Line->rsplit(':');
226         uint64_t TakenCount, Value;
227         if (ValueKind == IPVK_IndirectCallTarget) {
228           if (InstrProfSymtab::isExternalSymbol(VD.first)) {
229             Value = 0;
230           } else {
231             if (Error E = Symtab->addFuncName(VD.first))
232               return E;
233             Value = IndexedInstrProf::ComputeHash(VD.first);
234           }
235         } else {
236           READ_NUM(VD.first, Value);
237         }
238         READ_NUM(VD.second, TakenCount);
239         CurrentValues.push_back({Value, TakenCount});
240         Line++;
241       }
242       Record.addValueData(ValueKind, S, CurrentValues.data(), NumValueData,
243                           nullptr);
244     }
245   }
246   return success();
247 
248 #undef CHECK_LINE_END
249 #undef READ_NUM
250 #undef VP_READ_ADVANCE
251 }
252 
253 Error TextInstrProfReader::readNextRecord(NamedInstrProfRecord &Record) {
254   // Skip empty lines and comments.
255   while (!Line.is_at_end() && (Line->empty() || Line->startswith("#")))
256     ++Line;
257   // If we hit EOF while looking for a name, we're done.
258   if (Line.is_at_end()) {
259     return error(instrprof_error::eof);
260   }
261 
262   // Read the function name.
263   Record.Name = *Line++;
264   if (Error E = Symtab->addFuncName(Record.Name))
265     return error(std::move(E));
266 
267   // Read the function hash.
268   if (Line.is_at_end())
269     return error(instrprof_error::truncated);
270   if ((Line++)->getAsInteger(0, Record.Hash))
271     return error(instrprof_error::malformed);
272 
273   // Read the number of counters.
274   uint64_t NumCounters;
275   if (Line.is_at_end())
276     return error(instrprof_error::truncated);
277   if ((Line++)->getAsInteger(10, NumCounters))
278     return error(instrprof_error::malformed);
279   if (NumCounters == 0)
280     return error(instrprof_error::malformed);
281 
282   // Read each counter and fill our internal storage with the values.
283   Record.Clear();
284   Record.Counts.reserve(NumCounters);
285   for (uint64_t I = 0; I < NumCounters; ++I) {
286     if (Line.is_at_end())
287       return error(instrprof_error::truncated);
288     uint64_t Count;
289     if ((Line++)->getAsInteger(10, Count))
290       return error(instrprof_error::malformed);
291     Record.Counts.push_back(Count);
292   }
293 
294   // Check if value profile data exists and read it if so.
295   if (Error E = readValueProfileData(Record))
296     return error(std::move(E));
297 
298   return success();
299 }
300 
301 template <class IntPtrT>
302 bool RawInstrProfReader<IntPtrT>::hasFormat(const MemoryBuffer &DataBuffer) {
303   if (DataBuffer.getBufferSize() < sizeof(uint64_t))
304     return false;
305   uint64_t Magic =
306     *reinterpret_cast<const uint64_t *>(DataBuffer.getBufferStart());
307   return RawInstrProf::getMagic<IntPtrT>() == Magic ||
308          sys::getSwappedBytes(RawInstrProf::getMagic<IntPtrT>()) == Magic;
309 }
310 
311 template <class IntPtrT>
312 Error RawInstrProfReader<IntPtrT>::readHeader() {
313   if (!hasFormat(*DataBuffer))
314     return error(instrprof_error::bad_magic);
315   if (DataBuffer->getBufferSize() < sizeof(RawInstrProf::Header))
316     return error(instrprof_error::bad_header);
317   auto *Header = reinterpret_cast<const RawInstrProf::Header *>(
318       DataBuffer->getBufferStart());
319   ShouldSwapBytes = Header->Magic != RawInstrProf::getMagic<IntPtrT>();
320   return readHeader(*Header);
321 }
322 
323 template <class IntPtrT>
324 Error RawInstrProfReader<IntPtrT>::readNextHeader(const char *CurrentPos) {
325   const char *End = DataBuffer->getBufferEnd();
326   // Skip zero padding between profiles.
327   while (CurrentPos != End && *CurrentPos == 0)
328     ++CurrentPos;
329   // If there's nothing left, we're done.
330   if (CurrentPos == End)
331     return make_error<InstrProfError>(instrprof_error::eof);
332   // If there isn't enough space for another header, this is probably just
333   // garbage at the end of the file.
334   if (CurrentPos + sizeof(RawInstrProf::Header) > End)
335     return make_error<InstrProfError>(instrprof_error::malformed);
336   // The writer ensures each profile is padded to start at an aligned address.
337   if (reinterpret_cast<size_t>(CurrentPos) % alignof(uint64_t))
338     return make_error<InstrProfError>(instrprof_error::malformed);
339   // The magic should have the same byte order as in the previous header.
340   uint64_t Magic = *reinterpret_cast<const uint64_t *>(CurrentPos);
341   if (Magic != swap(RawInstrProf::getMagic<IntPtrT>()))
342     return make_error<InstrProfError>(instrprof_error::bad_magic);
343 
344   // There's another profile to read, so we need to process the header.
345   auto *Header = reinterpret_cast<const RawInstrProf::Header *>(CurrentPos);
346   return readHeader(*Header);
347 }
348 
349 template <class IntPtrT>
350 Error RawInstrProfReader<IntPtrT>::createSymtab(InstrProfSymtab &Symtab) {
351   if (Error E = Symtab.create(StringRef(NamesStart, NamesSize)))
352     return error(std::move(E));
353   for (const RawInstrProf::ProfileData<IntPtrT> *I = Data; I != DataEnd; ++I) {
354     const IntPtrT FPtr = swap(I->FunctionPointer);
355     if (!FPtr)
356       continue;
357     Symtab.mapAddress(FPtr, I->NameRef);
358   }
359   return success();
360 }
361 
362 template <class IntPtrT>
363 Error RawInstrProfReader<IntPtrT>::readHeader(
364     const RawInstrProf::Header &Header) {
365   Version = swap(Header.Version);
366   if (GET_VERSION(Version) != RawInstrProf::Version)
367     return error(instrprof_error::unsupported_version);
368 
369   BinaryIdsSize = swap(Header.BinaryIdsSize);
370   CountersDelta = swap(Header.CountersDelta);
371   NamesDelta = swap(Header.NamesDelta);
372   auto DataSize = swap(Header.DataSize);
373   auto PaddingBytesBeforeCounters = swap(Header.PaddingBytesBeforeCounters);
374   auto CountersSize = swap(Header.CountersSize);
375   auto PaddingBytesAfterCounters = swap(Header.PaddingBytesAfterCounters);
376   NamesSize = swap(Header.NamesSize);
377   ValueKindLast = swap(Header.ValueKindLast);
378 
379   auto DataSizeInBytes = DataSize * sizeof(RawInstrProf::ProfileData<IntPtrT>);
380   auto PaddingSize = getNumPaddingBytes(NamesSize);
381 
382   // Profile data starts after profile header and binary ids if exist.
383   ptrdiff_t DataOffset = sizeof(RawInstrProf::Header) + BinaryIdsSize;
384   ptrdiff_t CountersOffset =
385       DataOffset + DataSizeInBytes + PaddingBytesBeforeCounters;
386   ptrdiff_t NamesOffset = CountersOffset + (sizeof(uint64_t) * CountersSize) +
387                           PaddingBytesAfterCounters;
388   ptrdiff_t ValueDataOffset = NamesOffset + NamesSize + PaddingSize;
389 
390   auto *Start = reinterpret_cast<const char *>(&Header);
391   if (Start + ValueDataOffset > DataBuffer->getBufferEnd())
392     return error(instrprof_error::bad_header);
393 
394   Data = reinterpret_cast<const RawInstrProf::ProfileData<IntPtrT> *>(
395       Start + DataOffset);
396   DataEnd = Data + DataSize;
397 
398   // Binary ids start just after the header.
399   BinaryIdsStart =
400       reinterpret_cast<const uint8_t *>(&Header) + sizeof(RawInstrProf::Header);
401   CountersStart = reinterpret_cast<const uint64_t *>(Start + CountersOffset);
402   NamesStart = Start + NamesOffset;
403   ValueDataStart = reinterpret_cast<const uint8_t *>(Start + ValueDataOffset);
404 
405   std::unique_ptr<InstrProfSymtab> NewSymtab = std::make_unique<InstrProfSymtab>();
406   if (Error E = createSymtab(*NewSymtab.get()))
407     return E;
408 
409   Symtab = std::move(NewSymtab);
410   return success();
411 }
412 
413 template <class IntPtrT>
414 Error RawInstrProfReader<IntPtrT>::readName(NamedInstrProfRecord &Record) {
415   Record.Name = getName(Data->NameRef);
416   return success();
417 }
418 
419 template <class IntPtrT>
420 Error RawInstrProfReader<IntPtrT>::readFuncHash(NamedInstrProfRecord &Record) {
421   Record.Hash = swap(Data->FuncHash);
422   return success();
423 }
424 
425 template <class IntPtrT>
426 Error RawInstrProfReader<IntPtrT>::readRawCounts(
427     InstrProfRecord &Record) {
428   uint32_t NumCounters = swap(Data->NumCounters);
429   IntPtrT CounterPtr = Data->CounterPtr;
430   if (NumCounters == 0)
431     return error(instrprof_error::malformed);
432 
433   auto *NamesStartAsCounter = reinterpret_cast<const uint64_t *>(NamesStart);
434   ptrdiff_t MaxNumCounters = NamesStartAsCounter - CountersStart;
435 
436   // Check bounds. Note that the counter pointer embedded in the data record
437   // may itself be corrupt.
438   if (MaxNumCounters < 0 || NumCounters > (uint32_t)MaxNumCounters)
439     return error(instrprof_error::malformed);
440   ptrdiff_t CounterOffset = getCounterOffset(CounterPtr);
441   if (CounterOffset < 0 || CounterOffset > MaxNumCounters ||
442       ((uint32_t)CounterOffset + NumCounters) > (uint32_t)MaxNumCounters)
443     return error(instrprof_error::malformed);
444 
445   auto RawCounts = makeArrayRef(getCounter(CounterOffset), NumCounters);
446 
447   if (ShouldSwapBytes) {
448     Record.Counts.clear();
449     Record.Counts.reserve(RawCounts.size());
450     for (uint64_t Count : RawCounts)
451       Record.Counts.push_back(swap(Count));
452   } else
453     Record.Counts = RawCounts;
454 
455   return success();
456 }
457 
458 template <class IntPtrT>
459 Error RawInstrProfReader<IntPtrT>::readValueProfilingData(
460     InstrProfRecord &Record) {
461   Record.clearValueData();
462   CurValueDataSize = 0;
463   // Need to match the logic in value profile dumper code in compiler-rt:
464   uint32_t NumValueKinds = 0;
465   for (uint32_t I = 0; I < IPVK_Last + 1; I++)
466     NumValueKinds += (Data->NumValueSites[I] != 0);
467 
468   if (!NumValueKinds)
469     return success();
470 
471   Expected<std::unique_ptr<ValueProfData>> VDataPtrOrErr =
472       ValueProfData::getValueProfData(
473           ValueDataStart, (const unsigned char *)DataBuffer->getBufferEnd(),
474           getDataEndianness());
475 
476   if (Error E = VDataPtrOrErr.takeError())
477     return E;
478 
479   // Note that besides deserialization, this also performs the conversion for
480   // indirect call targets.  The function pointers from the raw profile are
481   // remapped into function name hashes.
482   VDataPtrOrErr.get()->deserializeTo(Record, Symtab.get());
483   CurValueDataSize = VDataPtrOrErr.get()->getSize();
484   return success();
485 }
486 
487 template <class IntPtrT>
488 Error RawInstrProfReader<IntPtrT>::readNextRecord(NamedInstrProfRecord &Record) {
489   if (atEnd())
490     // At this point, ValueDataStart field points to the next header.
491     if (Error E = readNextHeader(getNextHeaderPos()))
492       return error(std::move(E));
493 
494   // Read name ad set it in Record.
495   if (Error E = readName(Record))
496     return error(std::move(E));
497 
498   // Read FuncHash and set it in Record.
499   if (Error E = readFuncHash(Record))
500     return error(std::move(E));
501 
502   // Read raw counts and set Record.
503   if (Error E = readRawCounts(Record))
504     return error(std::move(E));
505 
506   // Read value data and set Record.
507   if (Error E = readValueProfilingData(Record))
508     return error(std::move(E));
509 
510   // Iterate.
511   advanceData();
512   return success();
513 }
514 
515 template <class IntPtrT>
516 Error RawInstrProfReader<IntPtrT>::printBinaryIds(raw_ostream &OS) {
517   if (BinaryIdsSize == 0)
518     return success();
519 
520   OS << "Binary IDs: \n";
521   const uint8_t *BI = BinaryIdsStart;
522   while (BI < BinaryIdsStart + BinaryIdsSize) {
523     uint64_t BinaryIdLen = swap(*reinterpret_cast<const uint64_t *>(BI));
524     // Increment by binary id length data type size.
525     BI += sizeof(BinaryIdLen);
526     if (BI > (const uint8_t *)DataBuffer->getBufferEnd())
527       return make_error<InstrProfError>(instrprof_error::malformed);
528 
529     for (uint64_t I = 0; I < BinaryIdLen; I++)
530       OS << format("%02x", BI[I]);
531     OS << "\n";
532 
533     // Increment by binary id data length.
534     BI += BinaryIdLen;
535     if (BI > (const uint8_t *)DataBuffer->getBufferEnd())
536       return make_error<InstrProfError>(instrprof_error::malformed);
537   }
538 
539   return success();
540 }
541 
542 namespace llvm {
543 
544 template class RawInstrProfReader<uint32_t>;
545 template class RawInstrProfReader<uint64_t>;
546 
547 } // end namespace llvm
548 
549 InstrProfLookupTrait::hash_value_type
550 InstrProfLookupTrait::ComputeHash(StringRef K) {
551   return IndexedInstrProf::ComputeHash(HashType, K);
552 }
553 
554 using data_type = InstrProfLookupTrait::data_type;
555 using offset_type = InstrProfLookupTrait::offset_type;
556 
557 bool InstrProfLookupTrait::readValueProfilingData(
558     const unsigned char *&D, const unsigned char *const End) {
559   Expected<std::unique_ptr<ValueProfData>> VDataPtrOrErr =
560       ValueProfData::getValueProfData(D, End, ValueProfDataEndianness);
561 
562   if (VDataPtrOrErr.takeError())
563     return false;
564 
565   VDataPtrOrErr.get()->deserializeTo(DataBuffer.back(), nullptr);
566   D += VDataPtrOrErr.get()->TotalSize;
567 
568   return true;
569 }
570 
571 data_type InstrProfLookupTrait::ReadData(StringRef K, const unsigned char *D,
572                                          offset_type N) {
573   using namespace support;
574 
575   // Check if the data is corrupt. If so, don't try to read it.
576   if (N % sizeof(uint64_t))
577     return data_type();
578 
579   DataBuffer.clear();
580   std::vector<uint64_t> CounterBuffer;
581 
582   const unsigned char *End = D + N;
583   while (D < End) {
584     // Read hash.
585     if (D + sizeof(uint64_t) >= End)
586       return data_type();
587     uint64_t Hash = endian::readNext<uint64_t, little, unaligned>(D);
588 
589     // Initialize number of counters for GET_VERSION(FormatVersion) == 1.
590     uint64_t CountsSize = N / sizeof(uint64_t) - 1;
591     // If format version is different then read the number of counters.
592     if (GET_VERSION(FormatVersion) != IndexedInstrProf::ProfVersion::Version1) {
593       if (D + sizeof(uint64_t) > End)
594         return data_type();
595       CountsSize = endian::readNext<uint64_t, little, unaligned>(D);
596     }
597     // Read counter values.
598     if (D + CountsSize * sizeof(uint64_t) > End)
599       return data_type();
600 
601     CounterBuffer.clear();
602     CounterBuffer.reserve(CountsSize);
603     for (uint64_t J = 0; J < CountsSize; ++J)
604       CounterBuffer.push_back(endian::readNext<uint64_t, little, unaligned>(D));
605 
606     DataBuffer.emplace_back(K, Hash, std::move(CounterBuffer));
607 
608     // Read value profiling data.
609     if (GET_VERSION(FormatVersion) > IndexedInstrProf::ProfVersion::Version2 &&
610         !readValueProfilingData(D, End)) {
611       DataBuffer.clear();
612       return data_type();
613     }
614   }
615   return DataBuffer;
616 }
617 
618 template <typename HashTableImpl>
619 Error InstrProfReaderIndex<HashTableImpl>::getRecords(
620     StringRef FuncName, ArrayRef<NamedInstrProfRecord> &Data) {
621   auto Iter = HashTable->find(FuncName);
622   if (Iter == HashTable->end())
623     return make_error<InstrProfError>(instrprof_error::unknown_function);
624 
625   Data = (*Iter);
626   if (Data.empty())
627     return make_error<InstrProfError>(instrprof_error::malformed);
628 
629   return Error::success();
630 }
631 
632 template <typename HashTableImpl>
633 Error InstrProfReaderIndex<HashTableImpl>::getRecords(
634     ArrayRef<NamedInstrProfRecord> &Data) {
635   if (atEnd())
636     return make_error<InstrProfError>(instrprof_error::eof);
637 
638   Data = *RecordIterator;
639 
640   if (Data.empty())
641     return make_error<InstrProfError>(instrprof_error::malformed);
642 
643   return Error::success();
644 }
645 
646 template <typename HashTableImpl>
647 InstrProfReaderIndex<HashTableImpl>::InstrProfReaderIndex(
648     const unsigned char *Buckets, const unsigned char *const Payload,
649     const unsigned char *const Base, IndexedInstrProf::HashT HashType,
650     uint64_t Version) {
651   FormatVersion = Version;
652   HashTable.reset(HashTableImpl::Create(
653       Buckets, Payload, Base,
654       typename HashTableImpl::InfoType(HashType, Version)));
655   RecordIterator = HashTable->data_begin();
656 }
657 
658 namespace {
659 /// A remapper that does not apply any remappings.
660 class InstrProfReaderNullRemapper : public InstrProfReaderRemapper {
661   InstrProfReaderIndexBase &Underlying;
662 
663 public:
664   InstrProfReaderNullRemapper(InstrProfReaderIndexBase &Underlying)
665       : Underlying(Underlying) {}
666 
667   Error getRecords(StringRef FuncName,
668                    ArrayRef<NamedInstrProfRecord> &Data) override {
669     return Underlying.getRecords(FuncName, Data);
670   }
671 };
672 }
673 
674 /// A remapper that applies remappings based on a symbol remapping file.
675 template <typename HashTableImpl>
676 class llvm::InstrProfReaderItaniumRemapper
677     : public InstrProfReaderRemapper {
678 public:
679   InstrProfReaderItaniumRemapper(
680       std::unique_ptr<MemoryBuffer> RemapBuffer,
681       InstrProfReaderIndex<HashTableImpl> &Underlying)
682       : RemapBuffer(std::move(RemapBuffer)), Underlying(Underlying) {
683   }
684 
685   /// Extract the original function name from a PGO function name.
686   static StringRef extractName(StringRef Name) {
687     // We can have multiple :-separated pieces; there can be pieces both
688     // before and after the mangled name. Find the first part that starts
689     // with '_Z'; we'll assume that's the mangled name we want.
690     std::pair<StringRef, StringRef> Parts = {StringRef(), Name};
691     while (true) {
692       Parts = Parts.second.split(':');
693       if (Parts.first.startswith("_Z"))
694         return Parts.first;
695       if (Parts.second.empty())
696         return Name;
697     }
698   }
699 
700   /// Given a mangled name extracted from a PGO function name, and a new
701   /// form for that mangled name, reconstitute the name.
702   static void reconstituteName(StringRef OrigName, StringRef ExtractedName,
703                                StringRef Replacement,
704                                SmallVectorImpl<char> &Out) {
705     Out.reserve(OrigName.size() + Replacement.size() - ExtractedName.size());
706     Out.insert(Out.end(), OrigName.begin(), ExtractedName.begin());
707     Out.insert(Out.end(), Replacement.begin(), Replacement.end());
708     Out.insert(Out.end(), ExtractedName.end(), OrigName.end());
709   }
710 
711   Error populateRemappings() override {
712     if (Error E = Remappings.read(*RemapBuffer))
713       return E;
714     for (StringRef Name : Underlying.HashTable->keys()) {
715       StringRef RealName = extractName(Name);
716       if (auto Key = Remappings.insert(RealName)) {
717         // FIXME: We could theoretically map the same equivalence class to
718         // multiple names in the profile data. If that happens, we should
719         // return NamedInstrProfRecords from all of them.
720         MappedNames.insert({Key, RealName});
721       }
722     }
723     return Error::success();
724   }
725 
726   Error getRecords(StringRef FuncName,
727                    ArrayRef<NamedInstrProfRecord> &Data) override {
728     StringRef RealName = extractName(FuncName);
729     if (auto Key = Remappings.lookup(RealName)) {
730       StringRef Remapped = MappedNames.lookup(Key);
731       if (!Remapped.empty()) {
732         if (RealName.begin() == FuncName.begin() &&
733             RealName.end() == FuncName.end())
734           FuncName = Remapped;
735         else {
736           // Try rebuilding the name from the given remapping.
737           SmallString<256> Reconstituted;
738           reconstituteName(FuncName, RealName, Remapped, Reconstituted);
739           Error E = Underlying.getRecords(Reconstituted, Data);
740           if (!E)
741             return E;
742 
743           // If we failed because the name doesn't exist, fall back to asking
744           // about the original name.
745           if (Error Unhandled = handleErrors(
746                   std::move(E), [](std::unique_ptr<InstrProfError> Err) {
747                     return Err->get() == instrprof_error::unknown_function
748                                ? Error::success()
749                                : Error(std::move(Err));
750                   }))
751             return Unhandled;
752         }
753       }
754     }
755     return Underlying.getRecords(FuncName, Data);
756   }
757 
758 private:
759   /// The memory buffer containing the remapping configuration. Remappings
760   /// holds pointers into this buffer.
761   std::unique_ptr<MemoryBuffer> RemapBuffer;
762 
763   /// The mangling remapper.
764   SymbolRemappingReader Remappings;
765 
766   /// Mapping from mangled name keys to the name used for the key in the
767   /// profile data.
768   /// FIXME: Can we store a location within the on-disk hash table instead of
769   /// redoing lookup?
770   DenseMap<SymbolRemappingReader::Key, StringRef> MappedNames;
771 
772   /// The real profile data reader.
773   InstrProfReaderIndex<HashTableImpl> &Underlying;
774 };
775 
776 bool IndexedInstrProfReader::hasFormat(const MemoryBuffer &DataBuffer) {
777   using namespace support;
778 
779   if (DataBuffer.getBufferSize() < 8)
780     return false;
781   uint64_t Magic =
782       endian::read<uint64_t, little, aligned>(DataBuffer.getBufferStart());
783   // Verify that it's magical.
784   return Magic == IndexedInstrProf::Magic;
785 }
786 
787 const unsigned char *
788 IndexedInstrProfReader::readSummary(IndexedInstrProf::ProfVersion Version,
789                                     const unsigned char *Cur, bool UseCS) {
790   using namespace IndexedInstrProf;
791   using namespace support;
792 
793   if (Version >= IndexedInstrProf::Version4) {
794     const IndexedInstrProf::Summary *SummaryInLE =
795         reinterpret_cast<const IndexedInstrProf::Summary *>(Cur);
796     uint64_t NFields =
797         endian::byte_swap<uint64_t, little>(SummaryInLE->NumSummaryFields);
798     uint64_t NEntries =
799         endian::byte_swap<uint64_t, little>(SummaryInLE->NumCutoffEntries);
800     uint32_t SummarySize =
801         IndexedInstrProf::Summary::getSize(NFields, NEntries);
802     std::unique_ptr<IndexedInstrProf::Summary> SummaryData =
803         IndexedInstrProf::allocSummary(SummarySize);
804 
805     const uint64_t *Src = reinterpret_cast<const uint64_t *>(SummaryInLE);
806     uint64_t *Dst = reinterpret_cast<uint64_t *>(SummaryData.get());
807     for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
808       Dst[I] = endian::byte_swap<uint64_t, little>(Src[I]);
809 
810     SummaryEntryVector DetailedSummary;
811     for (unsigned I = 0; I < SummaryData->NumCutoffEntries; I++) {
812       const IndexedInstrProf::Summary::Entry &Ent = SummaryData->getEntry(I);
813       DetailedSummary.emplace_back((uint32_t)Ent.Cutoff, Ent.MinBlockCount,
814                                    Ent.NumBlocks);
815     }
816     std::unique_ptr<llvm::ProfileSummary> &Summary =
817         UseCS ? this->CS_Summary : this->Summary;
818 
819     // initialize InstrProfSummary using the SummaryData from disk.
820     Summary = std::make_unique<ProfileSummary>(
821         UseCS ? ProfileSummary::PSK_CSInstr : ProfileSummary::PSK_Instr,
822         DetailedSummary, SummaryData->get(Summary::TotalBlockCount),
823         SummaryData->get(Summary::MaxBlockCount),
824         SummaryData->get(Summary::MaxInternalBlockCount),
825         SummaryData->get(Summary::MaxFunctionCount),
826         SummaryData->get(Summary::TotalNumBlocks),
827         SummaryData->get(Summary::TotalNumFunctions));
828     return Cur + SummarySize;
829   } else {
830     // The older versions do not support a profile summary. This just computes
831     // an empty summary, which will not result in accurate hot/cold detection.
832     // We would need to call addRecord for all NamedInstrProfRecords to get the
833     // correct summary. However, this version is old (prior to early 2016) and
834     // has not been supporting an accurate summary for several years.
835     InstrProfSummaryBuilder Builder(ProfileSummaryBuilder::DefaultCutoffs);
836     Summary = Builder.getSummary();
837     return Cur;
838   }
839 }
840 
841 Error IndexedInstrProfReader::readHeader() {
842   using namespace support;
843 
844   const unsigned char *Start =
845       (const unsigned char *)DataBuffer->getBufferStart();
846   const unsigned char *Cur = Start;
847   if ((const unsigned char *)DataBuffer->getBufferEnd() - Cur < 24)
848     return error(instrprof_error::truncated);
849 
850   auto *Header = reinterpret_cast<const IndexedInstrProf::Header *>(Cur);
851   Cur += sizeof(IndexedInstrProf::Header);
852 
853   // Check the magic number.
854   uint64_t Magic = endian::byte_swap<uint64_t, little>(Header->Magic);
855   if (Magic != IndexedInstrProf::Magic)
856     return error(instrprof_error::bad_magic);
857 
858   // Read the version.
859   uint64_t FormatVersion = endian::byte_swap<uint64_t, little>(Header->Version);
860   if (GET_VERSION(FormatVersion) >
861       IndexedInstrProf::ProfVersion::CurrentVersion)
862     return error(instrprof_error::unsupported_version);
863 
864   Cur = readSummary((IndexedInstrProf::ProfVersion)FormatVersion, Cur,
865                     /* UseCS */ false);
866   if (FormatVersion & VARIANT_MASK_CSIR_PROF)
867     Cur = readSummary((IndexedInstrProf::ProfVersion)FormatVersion, Cur,
868                       /* UseCS */ true);
869 
870   // Read the hash type and start offset.
871   IndexedInstrProf::HashT HashType = static_cast<IndexedInstrProf::HashT>(
872       endian::byte_swap<uint64_t, little>(Header->HashType));
873   if (HashType > IndexedInstrProf::HashT::Last)
874     return error(instrprof_error::unsupported_hash_type);
875 
876   uint64_t HashOffset = endian::byte_swap<uint64_t, little>(Header->HashOffset);
877 
878   // The rest of the file is an on disk hash table.
879   auto IndexPtr =
880       std::make_unique<InstrProfReaderIndex<OnDiskHashTableImplV3>>(
881           Start + HashOffset, Cur, Start, HashType, FormatVersion);
882 
883   // Load the remapping table now if requested.
884   if (RemappingBuffer) {
885     Remapper = std::make_unique<
886         InstrProfReaderItaniumRemapper<OnDiskHashTableImplV3>>(
887         std::move(RemappingBuffer), *IndexPtr);
888     if (Error E = Remapper->populateRemappings())
889       return E;
890   } else {
891     Remapper = std::make_unique<InstrProfReaderNullRemapper>(*IndexPtr);
892   }
893   Index = std::move(IndexPtr);
894 
895   return success();
896 }
897 
898 InstrProfSymtab &IndexedInstrProfReader::getSymtab() {
899   if (Symtab.get())
900     return *Symtab.get();
901 
902   std::unique_ptr<InstrProfSymtab> NewSymtab = std::make_unique<InstrProfSymtab>();
903   if (Error E = Index->populateSymtab(*NewSymtab.get())) {
904     consumeError(error(InstrProfError::take(std::move(E))));
905   }
906 
907   Symtab = std::move(NewSymtab);
908   return *Symtab.get();
909 }
910 
911 Expected<InstrProfRecord>
912 IndexedInstrProfReader::getInstrProfRecord(StringRef FuncName,
913                                            uint64_t FuncHash) {
914   ArrayRef<NamedInstrProfRecord> Data;
915   Error Err = Remapper->getRecords(FuncName, Data);
916   if (Err)
917     return std::move(Err);
918   // Found it. Look for counters with the right hash.
919   for (unsigned I = 0, E = Data.size(); I < E; ++I) {
920     // Check for a match and fill the vector if there is one.
921     if (Data[I].Hash == FuncHash) {
922       return std::move(Data[I]);
923     }
924   }
925   return error(instrprof_error::hash_mismatch);
926 }
927 
928 Error IndexedInstrProfReader::getFunctionCounts(StringRef FuncName,
929                                                 uint64_t FuncHash,
930                                                 std::vector<uint64_t> &Counts) {
931   Expected<InstrProfRecord> Record = getInstrProfRecord(FuncName, FuncHash);
932   if (Error E = Record.takeError())
933     return error(std::move(E));
934 
935   Counts = Record.get().Counts;
936   return success();
937 }
938 
939 Error IndexedInstrProfReader::readNextRecord(NamedInstrProfRecord &Record) {
940   ArrayRef<NamedInstrProfRecord> Data;
941 
942   Error E = Index->getRecords(Data);
943   if (E)
944     return error(std::move(E));
945 
946   Record = Data[RecordIndex++];
947   if (RecordIndex >= Data.size()) {
948     Index->advanceToNextKey();
949     RecordIndex = 0;
950   }
951   return success();
952 }
953 
954 void InstrProfReader::accumulateCounts(CountSumOrPercent &Sum, bool IsCS) {
955   uint64_t NumFuncs = 0;
956   for (const auto &Func : *this) {
957     if (isIRLevelProfile()) {
958       bool FuncIsCS = NamedInstrProfRecord::hasCSFlagInHash(Func.Hash);
959       if (FuncIsCS != IsCS)
960         continue;
961     }
962     Func.accumulateCounts(Sum);
963     ++NumFuncs;
964   }
965   Sum.NumEntries = NumFuncs;
966 }
967