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 std::error_code
25 setupMemoryBuffer(std::string Path, std::unique_ptr<MemoryBuffer> &Buffer) {
26   if (std::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 std::error_code initializeReader(InstrProfReader &Reader) {
36   return Reader.readHeader();
37 }
38 
39 std::error_code
40 InstrProfReader::create(std::string Path,
41                         std::unique_ptr<InstrProfReader> &Result) {
42   // Set up the buffer to read.
43   std::unique_ptr<MemoryBuffer> Buffer;
44   if (std::error_code EC = setupMemoryBuffer(Path, Buffer))
45     return EC;
46 
47   // Create the reader.
48   if (IndexedInstrProfReader::hasFormat(*Buffer))
49     Result.reset(new IndexedInstrProfReader(std::move(Buffer)));
50   else if (RawInstrProfReader64::hasFormat(*Buffer))
51     Result.reset(new RawInstrProfReader64(std::move(Buffer)));
52   else if (RawInstrProfReader32::hasFormat(*Buffer))
53     Result.reset(new RawInstrProfReader32(std::move(Buffer)));
54   else
55     Result.reset(new TextInstrProfReader(std::move(Buffer)));
56 
57   // Initialize the reader and return the result.
58   return initializeReader(*Result);
59 }
60 
61 std::error_code IndexedInstrProfReader::create(
62     std::string Path, std::unique_ptr<IndexedInstrProfReader> &Result) {
63   // Set up the buffer to read.
64   std::unique_ptr<MemoryBuffer> Buffer;
65   if (std::error_code EC = setupMemoryBuffer(Path, Buffer))
66     return EC;
67 
68   // Create the reader.
69   if (!IndexedInstrProfReader::hasFormat(*Buffer))
70     return instrprof_error::bad_magic;
71   Result.reset(new IndexedInstrProfReader(std::move(Buffer)));
72 
73   // Initialize the reader and return the result.
74   return initializeReader(*Result);
75 }
76 
77 void InstrProfIterator::Increment() {
78   if (Reader->readNextRecord(Record))
79     *this = InstrProfIterator();
80 }
81 
82 std::error_code TextInstrProfReader::readNextRecord(InstrProfRecord &Record) {
83   // Skip empty lines.
84   while (!Line.is_at_end() && Line->empty())
85     ++Line;
86   // If we hit EOF while looking for a name, we're done.
87   if (Line.is_at_end())
88     return error(instrprof_error::eof);
89 
90   // Read the function name.
91   Record.Name = *Line++;
92 
93   // Read the function hash.
94   if (Line.is_at_end())
95     return error(instrprof_error::truncated);
96   if ((Line++)->getAsInteger(10, Record.Hash))
97     return error(instrprof_error::malformed);
98 
99   // Read the number of counters.
100   uint64_t NumCounters;
101   if (Line.is_at_end())
102     return error(instrprof_error::truncated);
103   if ((Line++)->getAsInteger(10, NumCounters))
104     return error(instrprof_error::malformed);
105   if (NumCounters == 0)
106     return error(instrprof_error::malformed);
107 
108   // Read each counter and fill our internal storage with the values.
109   Counts.clear();
110   Counts.reserve(NumCounters);
111   for (uint64_t I = 0; I < NumCounters; ++I) {
112     if (Line.is_at_end())
113       return error(instrprof_error::truncated);
114     uint64_t Count;
115     if ((Line++)->getAsInteger(10, Count))
116       return error(instrprof_error::malformed);
117     Counts.push_back(Count);
118   }
119   // Give the record a reference to our internal counter storage.
120   Record.Counts = Counts;
121 
122   return success();
123 }
124 
125 template <class IntPtrT>
126 static uint64_t getRawMagic();
127 
128 template <>
129 uint64_t getRawMagic<uint64_t>() {
130   return
131     uint64_t(255) << 56 |
132     uint64_t('l') << 48 |
133     uint64_t('p') << 40 |
134     uint64_t('r') << 32 |
135     uint64_t('o') << 24 |
136     uint64_t('f') << 16 |
137     uint64_t('r') <<  8 |
138     uint64_t(129);
139 }
140 
141 template <>
142 uint64_t getRawMagic<uint32_t>() {
143   return
144     uint64_t(255) << 56 |
145     uint64_t('l') << 48 |
146     uint64_t('p') << 40 |
147     uint64_t('r') << 32 |
148     uint64_t('o') << 24 |
149     uint64_t('f') << 16 |
150     uint64_t('R') <<  8 |
151     uint64_t(129);
152 }
153 
154 template <class IntPtrT>
155 bool RawInstrProfReader<IntPtrT>::hasFormat(const MemoryBuffer &DataBuffer) {
156   if (DataBuffer.getBufferSize() < sizeof(uint64_t))
157     return false;
158   uint64_t Magic =
159     *reinterpret_cast<const uint64_t *>(DataBuffer.getBufferStart());
160   return getRawMagic<IntPtrT>() == Magic ||
161     sys::getSwappedBytes(getRawMagic<IntPtrT>()) == Magic;
162 }
163 
164 template <class IntPtrT>
165 std::error_code RawInstrProfReader<IntPtrT>::readHeader() {
166   if (!hasFormat(*DataBuffer))
167     return error(instrprof_error::bad_magic);
168   if (DataBuffer->getBufferSize() < sizeof(RawHeader))
169     return error(instrprof_error::bad_header);
170   auto *Header =
171     reinterpret_cast<const RawHeader *>(DataBuffer->getBufferStart());
172   ShouldSwapBytes = Header->Magic != getRawMagic<IntPtrT>();
173   return readHeader(*Header);
174 }
175 
176 template <class IntPtrT>
177 std::error_code
178 RawInstrProfReader<IntPtrT>::readNextHeader(const char *CurrentPos) {
179   const char *End = DataBuffer->getBufferEnd();
180   // Skip zero padding between profiles.
181   while (CurrentPos != End && *CurrentPos == 0)
182     ++CurrentPos;
183   // If there's nothing left, we're done.
184   if (CurrentPos == End)
185     return instrprof_error::eof;
186   // If there isn't enough space for another header, this is probably just
187   // garbage at the end of the file.
188   if (CurrentPos + sizeof(RawHeader) > End)
189     return instrprof_error::malformed;
190   // The magic should have the same byte order as in the previous header.
191   uint64_t Magic = *reinterpret_cast<const uint64_t *>(CurrentPos);
192   if (Magic != swap(getRawMagic<IntPtrT>()))
193     return instrprof_error::bad_magic;
194 
195   // There's another profile to read, so we need to process the header.
196   auto *Header = reinterpret_cast<const RawHeader *>(CurrentPos);
197   return readHeader(*Header);
198 }
199 
200 static uint64_t getRawVersion() {
201   return 1;
202 }
203 
204 template <class IntPtrT>
205 std::error_code
206 RawInstrProfReader<IntPtrT>::readHeader(const RawHeader &Header) {
207   if (swap(Header.Version) != getRawVersion())
208     return error(instrprof_error::unsupported_version);
209 
210   CountersDelta = swap(Header.CountersDelta);
211   NamesDelta = swap(Header.NamesDelta);
212   auto DataSize = swap(Header.DataSize);
213   auto CountersSize = swap(Header.CountersSize);
214   auto NamesSize = swap(Header.NamesSize);
215 
216   ptrdiff_t DataOffset = sizeof(RawHeader);
217   ptrdiff_t CountersOffset = DataOffset + sizeof(ProfileData) * DataSize;
218   ptrdiff_t NamesOffset = CountersOffset + sizeof(uint64_t) * CountersSize;
219   size_t ProfileSize = NamesOffset + sizeof(char) * NamesSize;
220 
221   auto *Start = reinterpret_cast<const char *>(&Header);
222   if (Start + ProfileSize > DataBuffer->getBufferEnd())
223     return error(instrprof_error::bad_header);
224 
225   Data = reinterpret_cast<const ProfileData *>(Start + DataOffset);
226   DataEnd = Data + DataSize;
227   CountersStart = reinterpret_cast<const uint64_t *>(Start + CountersOffset);
228   NamesStart = Start + NamesOffset;
229   ProfileEnd = Start + ProfileSize;
230 
231   return success();
232 }
233 
234 template <class IntPtrT>
235 std::error_code
236 RawInstrProfReader<IntPtrT>::readNextRecord(InstrProfRecord &Record) {
237   if (Data == DataEnd)
238     if (std::error_code EC = readNextHeader(ProfileEnd))
239       return EC;
240 
241   // Get the raw data.
242   StringRef RawName(getName(Data->NamePtr), swap(Data->NameSize));
243   uint32_t NumCounters = swap(Data->NumCounters);
244   if (NumCounters == 0)
245     return error(instrprof_error::malformed);
246   auto RawCounts = makeArrayRef(getCounter(Data->CounterPtr), NumCounters);
247 
248   // Check bounds.
249   auto *NamesStartAsCounter = reinterpret_cast<const uint64_t *>(NamesStart);
250   if (RawName.data() < NamesStart ||
251       RawName.data() + RawName.size() > DataBuffer->getBufferEnd() ||
252       RawCounts.data() < CountersStart ||
253       RawCounts.data() + RawCounts.size() > NamesStartAsCounter)
254     return error(instrprof_error::malformed);
255 
256   // Store the data in Record, byte-swapping as necessary.
257   Record.Hash = swap(Data->FuncHash);
258   Record.Name = RawName;
259   if (ShouldSwapBytes) {
260     Counts.clear();
261     Counts.reserve(RawCounts.size());
262     for (uint64_t Count : RawCounts)
263       Counts.push_back(swap(Count));
264     Record.Counts = Counts;
265   } else
266     Record.Counts = RawCounts;
267 
268   // Iterate.
269   ++Data;
270   return success();
271 }
272 
273 namespace llvm {
274 template class RawInstrProfReader<uint32_t>;
275 template class RawInstrProfReader<uint64_t>;
276 }
277 
278 InstrProfLookupTrait::hash_value_type
279 InstrProfLookupTrait::ComputeHash(StringRef K) {
280   return IndexedInstrProf::ComputeHash(HashType, K);
281 }
282 
283 bool IndexedInstrProfReader::hasFormat(const MemoryBuffer &DataBuffer) {
284   if (DataBuffer.getBufferSize() < 8)
285     return false;
286   using namespace support;
287   uint64_t Magic =
288       endian::read<uint64_t, little, aligned>(DataBuffer.getBufferStart());
289   return Magic == IndexedInstrProf::Magic;
290 }
291 
292 std::error_code IndexedInstrProfReader::readHeader() {
293   const unsigned char *Start =
294       (const unsigned char *)DataBuffer->getBufferStart();
295   const unsigned char *Cur = Start;
296   if ((const unsigned char *)DataBuffer->getBufferEnd() - Cur < 24)
297     return error(instrprof_error::truncated);
298 
299   using namespace support;
300 
301   // Check the magic number.
302   uint64_t Magic = endian::readNext<uint64_t, little, unaligned>(Cur);
303   if (Magic != IndexedInstrProf::Magic)
304     return error(instrprof_error::bad_magic);
305 
306   // Read the version.
307   uint64_t Version = endian::readNext<uint64_t, little, unaligned>(Cur);
308   if (Version != IndexedInstrProf::Version)
309     return error(instrprof_error::unsupported_version);
310 
311   // Read the maximal function count.
312   MaxFunctionCount = endian::readNext<uint64_t, little, unaligned>(Cur);
313 
314   // Read the hash type and start offset.
315   IndexedInstrProf::HashT HashType = static_cast<IndexedInstrProf::HashT>(
316       endian::readNext<uint64_t, little, unaligned>(Cur));
317   if (HashType > IndexedInstrProf::HashT::Last)
318     return error(instrprof_error::unsupported_hash_type);
319   uint64_t HashOffset = endian::readNext<uint64_t, little, unaligned>(Cur);
320 
321   // The rest of the file is an on disk hash table.
322   Index.reset(InstrProfReaderIndex::Create(Start + HashOffset, Cur, Start,
323                                            InstrProfLookupTrait(HashType)));
324   // Set up our iterator for readNextRecord.
325   RecordIterator = Index->data_begin();
326 
327   return success();
328 }
329 
330 std::error_code IndexedInstrProfReader::getFunctionCounts(
331     StringRef FuncName, uint64_t &FuncHash, std::vector<uint64_t> &Counts) {
332   const auto &Iter = Index->find(FuncName);
333   if (Iter == Index->end())
334     return error(instrprof_error::unknown_function);
335 
336   // Found it. Make sure it's valid before giving back a result.
337   const InstrProfRecord &Record = *Iter;
338   if (Record.Name.empty())
339     return error(instrprof_error::malformed);
340   FuncHash = Record.Hash;
341   Counts = Record.Counts;
342   return success();
343 }
344 
345 std::error_code
346 IndexedInstrProfReader::readNextRecord(InstrProfRecord &Record) {
347   // Are we out of records?
348   if (RecordIterator == Index->data_end())
349     return error(instrprof_error::eof);
350 
351   // Read the next one.
352   Record = *RecordIterator;
353   ++RecordIterator;
354   if (Record.Name.empty())
355     return error(instrprof_error::malformed);
356   return success();
357 }
358