1 //=-- InstrProfReader.cpp - Instrumented profiling reader -------------------=//
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 reading profiling data for clang's
11 // instrumentation based PGO and coverage.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/ProfileData/InstrProfReader.h"
16 #include "llvm/ProfileData/InstrProf.h"
17 
18 #include "InstrProfIndexed.h"
19 
20 #include <cassert>
21 
22 using namespace llvm;
23 
24 static error_code setupMemoryBuffer(std::string Path,
25                                     std::unique_ptr<MemoryBuffer> &Buffer) {
26   if (error_code EC = MemoryBuffer::getFileOrSTDIN(Path, Buffer))
27     return EC;
28 
29   // Sanity check the file.
30   if (Buffer->getBufferSize() > std::numeric_limits<unsigned>::max())
31     return instrprof_error::too_large;
32   return instrprof_error::success;
33 }
34 
35 static error_code initializeReader(InstrProfReader &Reader) {
36   return Reader.readHeader();
37 }
38 
39 error_code InstrProfReader::create(std::string Path,
40                                    std::unique_ptr<InstrProfReader> &Result) {
41   // Set up the buffer to read.
42   std::unique_ptr<MemoryBuffer> Buffer;
43   if (error_code EC = setupMemoryBuffer(Path, Buffer))
44     return EC;
45 
46   // Create the reader.
47   if (IndexedInstrProfReader::hasFormat(*Buffer))
48     Result.reset(new IndexedInstrProfReader(std::move(Buffer)));
49   else if (RawInstrProfReader64::hasFormat(*Buffer))
50     Result.reset(new RawInstrProfReader64(std::move(Buffer)));
51   else if (RawInstrProfReader32::hasFormat(*Buffer))
52     Result.reset(new RawInstrProfReader32(std::move(Buffer)));
53   else
54     Result.reset(new TextInstrProfReader(std::move(Buffer)));
55 
56   // Initialize the reader and return the result.
57   return initializeReader(*Result);
58 }
59 
60 error_code IndexedInstrProfReader::create(
61     std::string Path, std::unique_ptr<IndexedInstrProfReader> &Result) {
62   // Set up the buffer to read.
63   std::unique_ptr<MemoryBuffer> Buffer;
64   if (error_code EC = setupMemoryBuffer(Path, Buffer))
65     return EC;
66 
67   // Create the reader.
68   if (!IndexedInstrProfReader::hasFormat(*Buffer))
69     return instrprof_error::bad_magic;
70   Result.reset(new IndexedInstrProfReader(std::move(Buffer)));
71 
72   // Initialize the reader and return the result.
73   return initializeReader(*Result);
74 }
75 
76 void InstrProfIterator::Increment() {
77   if (Reader->readNextRecord(Record))
78     *this = InstrProfIterator();
79 }
80 
81 error_code TextInstrProfReader::readNextRecord(InstrProfRecord &Record) {
82   // Skip empty lines.
83   while (!Line.is_at_end() && Line->empty())
84     ++Line;
85   // If we hit EOF while looking for a name, we're done.
86   if (Line.is_at_end())
87     return error(instrprof_error::eof);
88 
89   // Read the function name.
90   Record.Name = *Line++;
91 
92   // Read the function hash.
93   if (Line.is_at_end())
94     return error(instrprof_error::truncated);
95   if ((Line++)->getAsInteger(10, Record.Hash))
96     return error(instrprof_error::malformed);
97 
98   // Read the number of counters.
99   uint64_t NumCounters;
100   if (Line.is_at_end())
101     return error(instrprof_error::truncated);
102   if ((Line++)->getAsInteger(10, NumCounters))
103     return error(instrprof_error::malformed);
104   if (NumCounters == 0)
105     return error(instrprof_error::malformed);
106 
107   // Read each counter and fill our internal storage with the values.
108   Counts.clear();
109   Counts.reserve(NumCounters);
110   for (uint64_t I = 0; I < NumCounters; ++I) {
111     if (Line.is_at_end())
112       return error(instrprof_error::truncated);
113     uint64_t Count;
114     if ((Line++)->getAsInteger(10, Count))
115       return error(instrprof_error::malformed);
116     Counts.push_back(Count);
117   }
118   // Give the record a reference to our internal counter storage.
119   Record.Counts = Counts;
120 
121   return success();
122 }
123 
124 template <class IntPtrT>
125 static uint64_t getRawMagic();
126 
127 template <>
128 uint64_t getRawMagic<uint64_t>() {
129   return
130     uint64_t(255) << 56 |
131     uint64_t('l') << 48 |
132     uint64_t('p') << 40 |
133     uint64_t('r') << 32 |
134     uint64_t('o') << 24 |
135     uint64_t('f') << 16 |
136     uint64_t('r') <<  8 |
137     uint64_t(129);
138 }
139 
140 template <>
141 uint64_t getRawMagic<uint32_t>() {
142   return
143     uint64_t(255) << 56 |
144     uint64_t('l') << 48 |
145     uint64_t('p') << 40 |
146     uint64_t('r') << 32 |
147     uint64_t('o') << 24 |
148     uint64_t('f') << 16 |
149     uint64_t('R') <<  8 |
150     uint64_t(129);
151 }
152 
153 template <class IntPtrT>
154 bool RawInstrProfReader<IntPtrT>::hasFormat(const MemoryBuffer &DataBuffer) {
155   if (DataBuffer.getBufferSize() < sizeof(uint64_t))
156     return false;
157   uint64_t Magic =
158     *reinterpret_cast<const uint64_t *>(DataBuffer.getBufferStart());
159   return getRawMagic<IntPtrT>() == Magic ||
160     sys::SwapByteOrder(getRawMagic<IntPtrT>()) == Magic;
161 }
162 
163 template <class IntPtrT>
164 error_code RawInstrProfReader<IntPtrT>::readHeader() {
165   if (!hasFormat(*DataBuffer))
166     return error(instrprof_error::bad_magic);
167   if (DataBuffer->getBufferSize() < sizeof(RawHeader))
168     return error(instrprof_error::bad_header);
169   auto *Header =
170     reinterpret_cast<const RawHeader *>(DataBuffer->getBufferStart());
171   ShouldSwapBytes = Header->Magic != getRawMagic<IntPtrT>();
172   return readHeader(*Header);
173 }
174 
175 static uint64_t getRawVersion() {
176   return 1;
177 }
178 
179 template <class IntPtrT>
180 error_code RawInstrProfReader<IntPtrT>::readHeader(const RawHeader &Header) {
181   if (swap(Header.Version) != getRawVersion())
182     return error(instrprof_error::unsupported_version);
183 
184   CountersDelta = swap(Header.CountersDelta);
185   NamesDelta = swap(Header.NamesDelta);
186   auto DataSize = swap(Header.DataSize);
187   auto CountersSize = swap(Header.CountersSize);
188   auto NamesSize = swap(Header.NamesSize);
189 
190   ptrdiff_t DataOffset = sizeof(RawHeader);
191   ptrdiff_t CountersOffset = DataOffset + sizeof(ProfileData) * DataSize;
192   ptrdiff_t NamesOffset = CountersOffset + sizeof(uint64_t) * CountersSize;
193   size_t FileSize = NamesOffset + sizeof(char) * NamesSize;
194 
195   if (FileSize != DataBuffer->getBufferSize())
196     return error(instrprof_error::bad_header);
197 
198   const char *Start = DataBuffer->getBufferStart();
199   Data = reinterpret_cast<const ProfileData *>(Start + DataOffset);
200   DataEnd = Data + DataSize;
201   CountersStart = reinterpret_cast<const uint64_t *>(Start + CountersOffset);
202   NamesStart = Start + NamesOffset;
203 
204   return success();
205 }
206 
207 template <class IntPtrT>
208 error_code
209 RawInstrProfReader<IntPtrT>::readNextRecord(InstrProfRecord &Record) {
210   if (Data == DataEnd)
211     return error(instrprof_error::eof);
212 
213   // Get the raw data.
214   StringRef RawName(getName(Data->NamePtr), swap(Data->NameSize));
215   uint32_t NumCounters = swap(Data->NumCounters);
216   if (NumCounters == 0)
217     return error(instrprof_error::malformed);
218   auto RawCounts = makeArrayRef(getCounter(Data->CounterPtr), NumCounters);
219 
220   // Check bounds.
221   auto *NamesStartAsCounter = reinterpret_cast<const uint64_t *>(NamesStart);
222   if (RawName.data() < NamesStart ||
223       RawName.data() + RawName.size() > DataBuffer->getBufferEnd() ||
224       RawCounts.data() < CountersStart ||
225       RawCounts.data() + RawCounts.size() > NamesStartAsCounter)
226     return error(instrprof_error::malformed);
227 
228   // Store the data in Record, byte-swapping as necessary.
229   Record.Hash = swap(Data->FuncHash);
230   Record.Name = RawName;
231   if (ShouldSwapBytes) {
232     Counts.clear();
233     Counts.reserve(RawCounts.size());
234     for (uint64_t Count : RawCounts)
235       Counts.push_back(swap(Count));
236     Record.Counts = Counts;
237   } else
238     Record.Counts = RawCounts;
239 
240   // Iterate.
241   ++Data;
242   return success();
243 }
244 
245 namespace llvm {
246 template class RawInstrProfReader<uint32_t>;
247 template class RawInstrProfReader<uint64_t>;
248 }
249 
250 InstrProfLookupTrait::hash_value_type
251 InstrProfLookupTrait::ComputeHash(StringRef K) {
252   return IndexedInstrProf::ComputeHash(HashType, K);
253 }
254 
255 bool IndexedInstrProfReader::hasFormat(const MemoryBuffer &DataBuffer) {
256   if (DataBuffer.getBufferSize() < 8)
257     return false;
258   using namespace support;
259   uint64_t Magic =
260       endian::read<uint64_t, little, aligned>(DataBuffer.getBufferStart());
261   return Magic == IndexedInstrProf::Magic;
262 }
263 
264 error_code IndexedInstrProfReader::readHeader() {
265   const unsigned char *Start =
266       (const unsigned char *)DataBuffer->getBufferStart();
267   const unsigned char *Cur = Start;
268   if ((const unsigned char *)DataBuffer->getBufferEnd() - Cur < 24)
269     return error(instrprof_error::truncated);
270 
271   using namespace support;
272 
273   // Check the magic number.
274   uint64_t Magic = endian::readNext<uint64_t, little, unaligned>(Cur);
275   if (Magic != IndexedInstrProf::Magic)
276     return error(instrprof_error::bad_magic);
277 
278   // Read the version.
279   uint64_t Version = endian::readNext<uint64_t, little, unaligned>(Cur);
280   if (Version != IndexedInstrProf::Version)
281     return error(instrprof_error::unsupported_version);
282 
283   // Read the maximal function count.
284   MaxFunctionCount = endian::readNext<uint64_t, little, unaligned>(Cur);
285 
286   // Read the hash type and start offset.
287   IndexedInstrProf::HashT HashType = static_cast<IndexedInstrProf::HashT>(
288       endian::readNext<uint64_t, little, unaligned>(Cur));
289   if (HashType > IndexedInstrProf::HashT::Last)
290     return error(instrprof_error::unsupported_hash_type);
291   uint64_t HashOffset = endian::readNext<uint64_t, little, unaligned>(Cur);
292 
293   // The rest of the file is an on disk hash table.
294   Index.reset(InstrProfReaderIndex::Create(Start + HashOffset, Cur, Start,
295                                            InstrProfLookupTrait(HashType)));
296   // Set up our iterator for readNextRecord.
297   RecordIterator = Index->data_begin();
298 
299   return success();
300 }
301 
302 error_code IndexedInstrProfReader::getFunctionCounts(
303     StringRef FuncName, uint64_t &FuncHash, std::vector<uint64_t> &Counts) {
304   const auto &Iter = Index->find(FuncName);
305   if (Iter == Index->end())
306     return error(instrprof_error::unknown_function);
307 
308   // Found it. Make sure it's valid before giving back a result.
309   const InstrProfRecord &Record = *Iter;
310   if (Record.Name.empty())
311     return error(instrprof_error::malformed);
312   FuncHash = Record.Hash;
313   Counts = Record.Counts;
314   return success();
315 }
316 
317 error_code IndexedInstrProfReader::readNextRecord(InstrProfRecord &Record) {
318   // Are we out of records?
319   if (RecordIterator == Index->data_end())
320     return error(instrprof_error::eof);
321 
322   // Read the next one.
323   Record = *RecordIterator;
324   ++RecordIterator;
325   if (Record.Name.empty())
326     return error(instrprof_error::malformed);
327   return success();
328 }
329