1 //===- CoverageMappingReader.h - Code coverage mapping reader ---*- C++ -*-===//
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 coverage mapping data for
10 // instrumentation based coverage.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_PROFILEDATA_COVERAGE_COVERAGEMAPPINGREADER_H
15 #define LLVM_PROFILEDATA_COVERAGE_COVERAGEMAPPINGREADER_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ProfileData/Coverage/CoverageMapping.h"
20 #include "llvm/ProfileData/InstrProf.h"
21 #include "llvm/Support/Error.h"
22 #include "llvm/Support/MemoryBuffer.h"
23 #include <cstddef>
24 #include <cstdint>
25 #include <iterator>
26 #include <memory>
27 #include <vector>
28 
29 namespace llvm {
30 namespace coverage {
31 
32 class CoverageMappingReader;
33 
34 /// Coverage mapping information for a single function.
35 struct CoverageMappingRecord {
36   StringRef FunctionName;
37   uint64_t FunctionHash;
38   ArrayRef<StringRef> Filenames;
39   ArrayRef<CounterExpression> Expressions;
40   ArrayRef<CounterMappingRegion> MappingRegions;
41 };
42 
43 /// A file format agnostic iterator over coverage mapping data.
44 class CoverageMappingIterator
45     : public std::iterator<std::input_iterator_tag, CoverageMappingRecord> {
46   CoverageMappingReader *Reader;
47   CoverageMappingRecord Record;
48   coveragemap_error ReadErr;
49 
50   void increment();
51 
52 public:
CoverageMappingIterator()53   CoverageMappingIterator()
54       : Reader(nullptr), Record(), ReadErr(coveragemap_error::success) {}
55 
CoverageMappingIterator(CoverageMappingReader * Reader)56   CoverageMappingIterator(CoverageMappingReader *Reader)
57       : Reader(Reader), Record(), ReadErr(coveragemap_error::success) {
58     increment();
59   }
60 
~CoverageMappingIterator()61   ~CoverageMappingIterator() {
62     if (ReadErr != coveragemap_error::success)
63       llvm_unreachable("Unexpected error in coverage mapping iterator");
64   }
65 
66   CoverageMappingIterator &operator++() {
67     increment();
68     return *this;
69   }
70   bool operator==(const CoverageMappingIterator &RHS) {
71     return Reader == RHS.Reader;
72   }
73   bool operator!=(const CoverageMappingIterator &RHS) {
74     return Reader != RHS.Reader;
75   }
76   Expected<CoverageMappingRecord &> operator*() {
77     if (ReadErr != coveragemap_error::success) {
78       auto E = make_error<CoverageMapError>(ReadErr);
79       ReadErr = coveragemap_error::success;
80       return std::move(E);
81     }
82     return Record;
83   }
84   Expected<CoverageMappingRecord *> operator->() {
85     if (ReadErr != coveragemap_error::success) {
86       auto E = make_error<CoverageMapError>(ReadErr);
87       ReadErr = coveragemap_error::success;
88       return std::move(E);
89     }
90     return &Record;
91   }
92 };
93 
94 class CoverageMappingReader {
95 public:
96   virtual ~CoverageMappingReader() = default;
97 
98   virtual Error readNextRecord(CoverageMappingRecord &Record) = 0;
begin()99   CoverageMappingIterator begin() { return CoverageMappingIterator(this); }
end()100   CoverageMappingIterator end() { return CoverageMappingIterator(); }
101 };
102 
103 /// Base class for the raw coverage mapping and filenames data readers.
104 class RawCoverageReader {
105 protected:
106   StringRef Data;
107 
RawCoverageReader(StringRef Data)108   RawCoverageReader(StringRef Data) : Data(Data) {}
109 
110   Error readULEB128(uint64_t &Result);
111   Error readIntMax(uint64_t &Result, uint64_t MaxPlus1);
112   Error readSize(uint64_t &Result);
113   Error readString(StringRef &Result);
114 };
115 
116 /// Checks if the given coverage mapping data is exported for
117 /// an unused function.
118 class RawCoverageMappingDummyChecker : public RawCoverageReader {
119 public:
RawCoverageMappingDummyChecker(StringRef MappingData)120   RawCoverageMappingDummyChecker(StringRef MappingData)
121       : RawCoverageReader(MappingData) {}
122 
123   Expected<bool> isDummy();
124 };
125 
126 /// Reader for the raw coverage mapping data.
127 class RawCoverageMappingReader : public RawCoverageReader {
128   ArrayRef<StringRef> TranslationUnitFilenames;
129   std::vector<StringRef> &Filenames;
130   std::vector<CounterExpression> &Expressions;
131   std::vector<CounterMappingRegion> &MappingRegions;
132 
133 public:
RawCoverageMappingReader(StringRef MappingData,ArrayRef<StringRef> TranslationUnitFilenames,std::vector<StringRef> & Filenames,std::vector<CounterExpression> & Expressions,std::vector<CounterMappingRegion> & MappingRegions)134   RawCoverageMappingReader(StringRef MappingData,
135                            ArrayRef<StringRef> TranslationUnitFilenames,
136                            std::vector<StringRef> &Filenames,
137                            std::vector<CounterExpression> &Expressions,
138                            std::vector<CounterMappingRegion> &MappingRegions)
139       : RawCoverageReader(MappingData),
140         TranslationUnitFilenames(TranslationUnitFilenames),
141         Filenames(Filenames), Expressions(Expressions),
142         MappingRegions(MappingRegions) {}
143   RawCoverageMappingReader(const RawCoverageMappingReader &) = delete;
144   RawCoverageMappingReader &
145   operator=(const RawCoverageMappingReader &) = delete;
146 
147   Error read();
148 
149 private:
150   Error decodeCounter(unsigned Value, Counter &C);
151   Error readCounter(Counter &C);
152   Error
153   readMappingRegionsSubArray(std::vector<CounterMappingRegion> &MappingRegions,
154                              unsigned InferredFileID, size_t NumFileIDs);
155 };
156 
157 /// Reader for the coverage mapping data that is emitted by the
158 /// frontend and stored in an object file.
159 class BinaryCoverageReader : public CoverageMappingReader {
160 public:
161   struct ProfileMappingRecord {
162     CovMapVersion Version;
163     StringRef FunctionName;
164     uint64_t FunctionHash;
165     StringRef CoverageMapping;
166     size_t FilenamesBegin;
167     size_t FilenamesSize;
168 
ProfileMappingRecordProfileMappingRecord169     ProfileMappingRecord(CovMapVersion Version, StringRef FunctionName,
170                          uint64_t FunctionHash, StringRef CoverageMapping,
171                          size_t FilenamesBegin, size_t FilenamesSize)
172         : Version(Version), FunctionName(FunctionName),
173           FunctionHash(FunctionHash), CoverageMapping(CoverageMapping),
174           FilenamesBegin(FilenamesBegin), FilenamesSize(FilenamesSize) {}
175   };
176 
177   using DecompressedData = std::vector<std::unique_ptr<SmallVector<char, 0>>>;
178 
179 private:
180   std::vector<StringRef> Filenames;
181   std::vector<ProfileMappingRecord> MappingRecords;
182   InstrProfSymtab ProfileNames;
183   size_t CurrentRecord = 0;
184   std::vector<StringRef> FunctionsFilenames;
185   std::vector<CounterExpression> Expressions;
186   std::vector<CounterMappingRegion> MappingRegions;
187 
188   // Used to tie the lifetimes of coverage function records to the lifetime of
189   // this BinaryCoverageReader instance. Needed to support the format change in
190   // D69471, which can split up function records into multiple sections on ELF.
191   std::string FuncRecords;
192 
193   // Used to tie the lifetimes of decompressed strings to the lifetime of this
194   // BinaryCoverageReader instance.
195   DecompressedData Decompressed;
196 
BinaryCoverageReader(std::string && FuncRecords)197   BinaryCoverageReader(std::string &&FuncRecords)
198       : FuncRecords(std::move(FuncRecords)) {}
199 
200 public:
201   BinaryCoverageReader(const BinaryCoverageReader &) = delete;
202   BinaryCoverageReader &operator=(const BinaryCoverageReader &) = delete;
203 
204   static Expected<std::vector<std::unique_ptr<BinaryCoverageReader>>>
205   create(MemoryBufferRef ObjectBuffer, StringRef Arch,
206          SmallVectorImpl<std::unique_ptr<MemoryBuffer>> &ObjectFileBuffers);
207 
208   static Expected<std::unique_ptr<BinaryCoverageReader>>
209   createCoverageReaderFromBuffer(StringRef Coverage, std::string &&FuncRecords,
210                                  InstrProfSymtab &&ProfileNames,
211                                  uint8_t BytesInAddress,
212                                  support::endianness Endian);
213 
214   Error readNextRecord(CoverageMappingRecord &Record) override;
215 };
216 
217 /// Reader for the raw coverage filenames.
218 class RawCoverageFilenamesReader : public RawCoverageReader {
219   std::vector<StringRef> &Filenames;
220 
221   // Read an uncompressed sequence of filenames.
222   Error readUncompressed(uint64_t NumFilenames);
223 
224 public:
RawCoverageFilenamesReader(StringRef Data,std::vector<StringRef> & Filenames)225   RawCoverageFilenamesReader(StringRef Data, std::vector<StringRef> &Filenames)
226       : RawCoverageReader(Data), Filenames(Filenames) {}
227   RawCoverageFilenamesReader(const RawCoverageFilenamesReader &) = delete;
228   RawCoverageFilenamesReader &
229   operator=(const RawCoverageFilenamesReader &) = delete;
230 
231   Error read(CovMapVersion Version,
232              BinaryCoverageReader::DecompressedData &Decompressed);
233 };
234 
235 } // end namespace coverage
236 } // end namespace llvm
237 
238 #endif // LLVM_PROFILEDATA_COVERAGE_COVERAGEMAPPINGREADER_H
239