1 //===- SampleProfReader.h - Read LLVM sample profile data -----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains definitions needed for reading sample profiles.
12 //===----------------------------------------------------------------------===//
13 #ifndef LLVM_PROFILEDATA_SAMPLEPROFREADER_H
14 #define LLVM_PROFILEDATA_SAMPLEPROFREADER_H
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/StringMap.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/IR/DiagnosticInfo.h"
21 #include "llvm/IR/Function.h"
22 #include "llvm/IR/LLVMContext.h"
23 #include "llvm/ProfileData/SampleProf.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/ErrorOr.h"
27 #include "llvm/Support/GCOV.h"
28 #include "llvm/Support/MemoryBuffer.h"
29 #include "llvm/Support/raw_ostream.h"
33 namespace sampleprof {
35 /// \brief Sample-based profile reader.
37 /// Each profile contains sample counts for all the functions
38 /// executed. Inside each function, statements are annotated with the
39 /// collected samples on all the instructions associated with that
42 /// For this to produce meaningful data, the program needs to be
43 /// compiled with some debug information (at minimum, line numbers:
44 /// -gline-tables-only). Otherwise, it will be impossible to match IR
45 /// instructions to the line numbers collected by the profiler.
47 /// From the profile file, we are interested in collecting the
48 /// following information:
50 /// * A list of functions included in the profile (mangled names).
52 /// * For each function F:
53 /// 1. The total number of samples collected in F.
55 /// 2. The samples collected at each line in F. To provide some
56 /// protection against source code shuffling, line numbers should
57 /// be relative to the start of the function.
59 /// The reader supports two file formats: text and binary. The text format
60 /// is useful for debugging and testing, while the binary format is more
61 /// compact and I/O efficient. They can both be used interchangeably.
62 class SampleProfileReader {
64 SampleProfileReader(std::unique_ptr<MemoryBuffer> B, LLVMContext &C)
65 : Profiles(0), Ctx(C), Buffer(std::move(B)) {}
67 virtual ~SampleProfileReader() {}
69 /// \brief Read and validate the file header.
70 virtual std::error_code readHeader() = 0;
72 /// \brief Read sample profiles from the associated file.
73 virtual std::error_code read() = 0;
75 /// \brief Print the profile for \p FName on stream \p OS.
76 void dumpFunctionProfile(StringRef FName, raw_ostream &OS = dbgs());
78 /// \brief Print all the profiles on stream \p OS.
79 void dump(raw_ostream &OS = dbgs());
81 /// \brief Return the samples collected for function \p F.
82 FunctionSamples *getSamplesFor(const Function &F) {
83 return &Profiles[F.getName()];
86 /// \brief Return all the profiles.
87 StringMap<FunctionSamples> &getProfiles() { return Profiles; }
89 /// \brief Report a parse error message.
90 void reportError(int64_t LineNumber, Twine Msg) const {
91 Ctx.diagnose(DiagnosticInfoSampleProfile(Buffer->getBufferIdentifier(),
95 /// \brief Create a sample profile reader appropriate to the file format.
96 static ErrorOr<std::unique_ptr<SampleProfileReader>>
97 create(StringRef Filename, LLVMContext &C);
100 /// \brief Map every function to its associated profile.
102 /// The profile of every function executed at runtime is collected
103 /// in the structure FunctionSamples. This maps function objects
104 /// to their corresponding profiles.
105 StringMap<FunctionSamples> Profiles;
107 /// \brief LLVM context used to emit diagnostics.
110 /// \brief Memory buffer holding the profile file.
111 std::unique_ptr<MemoryBuffer> Buffer;
114 class SampleProfileReaderText : public SampleProfileReader {
116 SampleProfileReaderText(std::unique_ptr<MemoryBuffer> B, LLVMContext &C)
117 : SampleProfileReader(std::move(B), C) {}
119 /// \brief Read and validate the file header.
120 std::error_code readHeader() override { return sampleprof_error::success; }
122 /// \brief Read sample profiles from the associated file.
123 std::error_code read() override;
126 class SampleProfileReaderBinary : public SampleProfileReader {
128 SampleProfileReaderBinary(std::unique_ptr<MemoryBuffer> B, LLVMContext &C)
129 : SampleProfileReader(std::move(B), C), Data(nullptr), End(nullptr) {}
131 /// \brief Read and validate the file header.
132 std::error_code readHeader() override;
134 /// \brief Read sample profiles from the associated file.
135 std::error_code read() override;
137 /// \brief Return true if \p Buffer is in the format supported by this class.
138 static bool hasFormat(const MemoryBuffer &Buffer);
141 /// \brief Read a numeric value of type T from the profile.
143 /// If an error occurs during decoding, a diagnostic message is emitted and
146 /// \returns the read value.
147 template <typename T> ErrorOr<T> readNumber();
149 /// \brief Read a string from the profile.
151 /// If an error occurs during decoding, a diagnostic message is emitted and
154 /// \returns the read value.
155 ErrorOr<StringRef> readString();
157 /// Read a string indirectly via the name table.
158 ErrorOr<StringRef> readStringFromTable();
160 /// \brief Return true if we've reached the end of file.
161 bool at_eof() const { return Data >= End; }
163 /// Read the contents of the given profile instance.
164 std::error_code readProfile(FunctionSamples &FProfile);
166 /// \brief Points to the current location in the buffer.
169 /// \brief Points to the end of the buffer.
172 /// Function name table.
173 std::vector<StringRef> NameTable;
176 typedef SmallVector<FunctionSamples *, 10> InlineCallStack;
178 // Supported histogram types in GCC. Currently, we only need support for
179 // call target histograms.
183 HIST_TYPE_SINGLE_VALUE,
184 HIST_TYPE_CONST_DELTA,
185 HIST_TYPE_INDIR_CALL,
188 HIST_TYPE_INDIR_CALL_TOPN
191 class SampleProfileReaderGCC : public SampleProfileReader {
193 SampleProfileReaderGCC(std::unique_ptr<MemoryBuffer> B, LLVMContext &C)
194 : SampleProfileReader(std::move(B), C), GcovBuffer(Buffer.get()) {}
196 /// \brief Read and validate the file header.
197 std::error_code readHeader() override;
199 /// \brief Read sample profiles from the associated file.
200 std::error_code read() override;
202 /// \brief Return true if \p Buffer is in the format supported by this class.
203 static bool hasFormat(const MemoryBuffer &Buffer);
206 std::error_code readNameTable();
207 std::error_code readOneFunctionProfile(const InlineCallStack &InlineStack,
208 bool Update, uint32_t Offset);
209 std::error_code readFunctionProfiles();
210 std::error_code skipNextWord();
211 template <typename T> ErrorOr<T> readNumber();
212 ErrorOr<StringRef> readString();
214 /// \brief Read the section tag and check that it's the same as \p Expected.
215 std::error_code readSectionTag(uint32_t Expected);
217 /// GCOV buffer containing the profile.
218 GCOVBuffer GcovBuffer;
220 /// Function names in this profile.
221 std::vector<std::string> Names;
223 /// GCOV tags used to separate sections in the profile file.
224 static const uint32_t GCOVTagAFDOFileNames = 0xaa000000;
225 static const uint32_t GCOVTagAFDOFunction = 0xac000000;
228 } // End namespace sampleprof
230 } // End namespace llvm
232 #endif // LLVM_PROFILEDATA_SAMPLEPROFREADER_H