FunctionInfo.h revision 360784 
1//===- FunctionInfo.h -------------------------------------------*- 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#ifndef LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H
10#define LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H
11
12#include "llvm/ADT/Optional.h"
13#include "llvm/DebugInfo/GSYM/InlineInfo.h"
14#include "llvm/DebugInfo/GSYM/LineTable.h"
15#include "llvm/DebugInfo/GSYM/LookupResult.h"
16#include "llvm/DebugInfo/GSYM/Range.h"
17#include "llvm/DebugInfo/GSYM/StringTable.h"
18#include <tuple>
19#include <vector>
20
21namespace llvm {
22class raw_ostream;
23namespace gsym {
24
25class GsymReader;
26/// Function information in GSYM files encodes information for one contiguous
27/// address range. If a function has discontiguous address ranges, they will
28/// need to be encoded using multiple FunctionInfo objects.
29///
30/// ENCODING
31///
32/// The function information gets the function start address as an argument
33/// to the FunctionInfo::decode(...) function. This information is calculated
34/// from the GSYM header and an address offset from the GSYM address offsets
35/// table. The encoded FunctionInfo information must be aligned to a 4 byte
36/// boundary.
37///
38/// The encoded data for a FunctionInfo starts with fixed data that all
39/// function info objects have:
40///
41/// ENCODING  NAME        DESCRIPTION
42/// ========= =========== ====================================================
43/// uint32_t  Size        The size in bytes of this function.
44/// uint32_t  Name        The string table offset of the function name.
45///
46/// The optional data in a FunctionInfo object follows this fixed information
47/// and consists of a stream of tuples that consist of:
48///
49/// ENCODING  NAME        DESCRIPTION
50/// ========= =========== ====================================================
51/// uint32_t  InfoType    An "InfoType" enumeration that describes the type
52///                       of optional data that is encoded.
53/// uint32_t  InfoLength  The size in bytes of the encoded data that
54///                       immediately follows this length if this value is
55///                       greater than zero.
56/// uint8_t[] InfoData    Encoded bytes that represent the data for the
57///                       "InfoType". These bytes are only present if
58///                       "InfoLength" is greater than zero.
59///
60/// The "InfoType" is an enumeration:
61///
62///   enum InfoType {
63///     EndOfList = 0u,
64///     LineTableInfo = 1u,
65///     InlineInfo = 2u
66///   };
67///
68/// This stream of tuples is terminated by a "InfoType" whose value is
69/// InfoType::EndOfList and a zero for "InfoLength". This signifies the end of
70/// the optional information list. This format allows us to add new optional
71/// information data to a FunctionInfo object over time and allows older
72/// clients to still parse the format and skip over any data that they don't
73/// understand or want to parse.
74///
75/// So the function information encoding essientially looks like:
76///
77/// struct {
78///   uint32_t Size;
79///   uint32_t Name;
80///   struct {
81///     uint32_t InfoType;
82///     uint32_t InfoLength;
83///     uint8_t InfoData[InfoLength];
84///   }[N];
85/// }
86///
87/// Where "N" is the number of tuples.
88struct FunctionInfo {
89  AddressRange Range;
90  uint32_t Name; ///< String table offset in the string table.
91  llvm::Optional<LineTable> OptLineTable;
92  llvm::Optional<InlineInfo> Inline;
93
94  FunctionInfo(uint64_t Addr = 0, uint64_t Size = 0, uint32_t N = 0)
95      : Range(Addr, Addr + Size), Name(N) {}
96
97  /// Query if a FunctionInfo has rich debug info.
98  ///
99  /// \returns A bool that indicates if this object has something else than
100  /// range and name. When converting information from a symbol table and from
101  /// debug info, we might end up with multiple FunctionInfo objects for the
102  /// same range and we need to be able to tell which one is the better object
103  /// to use.
104  bool hasRichInfo() const {
105    return OptLineTable.hasValue() || Inline.hasValue();
106  }
107
108  /// Query if a FunctionInfo object is valid.
109  ///
110  /// Address and size can be zero and there can be no line entries for a
111  /// symbol so the only indication this entry is valid is if the name is
112  /// not zero. This can happen when extracting information from symbol
113  /// tables that do not encode symbol sizes. In that case only the
114  /// address and name will be filled in.
115  ///
116  /// \returns A boolean indicating if this FunctionInfo is valid.
117  bool isValid() const {
118    return Name != 0;
119  }
120
121  /// Decode an object from a binary data stream.
122  ///
123  /// \param Data The binary stream to read the data from. This object must
124  /// have the data for the object starting at offset zero. The data
125  /// can contain more data than needed.
126  ///
127  /// \param BaseAddr The FunctionInfo's start address and will be used as the
128  /// base address when decoding any contained information like the line table
129  /// and the inline info.
130  ///
131  /// \returns An FunctionInfo or an error describing the issue that was
132  /// encountered during decoding.
133  static llvm::Expected<FunctionInfo> decode(DataExtractor &Data,
134                                             uint64_t BaseAddr);
135
136  /// Encode this object into FileWriter stream.
137  ///
138  /// \param O The binary stream to write the data to at the current file
139  /// position.
140  ///
141  /// \returns An error object that indicates failure or the offset of the
142  /// function info that was successfully written into the stream.
143  llvm::Expected<uint64_t> encode(FileWriter &O) const;
144
145
146  /// Lookup an address within a FunctionInfo object's data stream.
147  ///
148  /// Instead of decoding an entire FunctionInfo object when doing lookups,
149  /// we can decode only the information we need from the FunctionInfo's data
150  /// for the specific address. The lookup result information is returned as
151  /// a LookupResult.
152  ///
153  /// \param Data The binary stream to read the data from. This object must
154  /// have the data for the object starting at offset zero. The data
155  /// can contain more data than needed.
156  ///
157  /// \param GR The GSYM reader that contains the string and file table that
158  /// will be used to fill in information in the returned result.
159  ///
160  /// \param FuncAddr The function start address decoded from the GsymReader.
161  ///
162  /// \param Addr The address to lookup.
163  ///
164  /// \returns An LookupResult or an error describing the issue that was
165  /// encountered during decoding. An error should only be returned if the
166  /// address is not contained in the FunctionInfo or if the data is corrupted.
167  static llvm::Expected<LookupResult> lookup(DataExtractor &Data,
168                                             const GsymReader &GR,
169                                             uint64_t FuncAddr,
170                                             uint64_t Addr);
171
172  uint64_t startAddress() const { return Range.Start; }
173  uint64_t endAddress() const { return Range.End; }
174  uint64_t size() const { return Range.size(); }
175  void setStartAddress(uint64_t Addr) { Range.Start = Addr; }
176  void setEndAddress(uint64_t Addr) { Range.End = Addr; }
177  void setSize(uint64_t Size) { Range.End = Range.Start + Size; }
178
179  void clear() {
180    Range = {0, 0};
181    Name = 0;
182    OptLineTable = None;
183    Inline = None;
184  }
185};
186
187inline bool operator==(const FunctionInfo &LHS, const FunctionInfo &RHS) {
188  return LHS.Range == RHS.Range && LHS.Name == RHS.Name &&
189         LHS.OptLineTable == RHS.OptLineTable && LHS.Inline == RHS.Inline;
190}
191inline bool operator!=(const FunctionInfo &LHS, const FunctionInfo &RHS) {
192  return !(LHS == RHS);
193}
194/// This sorting will order things consistently by address range first, but then
195/// followed by inlining being valid and line tables. We might end up with a
196/// FunctionInfo from debug info that will have the same range as one from the
197/// symbol table, but we want to quickly be able to sort and use the best version
198/// when creating the final GSYM file.
199inline bool operator<(const FunctionInfo &LHS, const FunctionInfo &RHS) {
200  // First sort by address range
201  if (LHS.Range != RHS.Range)
202    return LHS.Range < RHS.Range;
203
204  // Then sort by inline
205  if (LHS.Inline.hasValue() != RHS.Inline.hasValue())
206    return RHS.Inline.hasValue();
207
208  return LHS.OptLineTable < RHS.OptLineTable;
209}
210
211raw_ostream &operator<<(raw_ostream &OS, const FunctionInfo &R);
212
213} // namespace gsym
214} // namespace llvm
215
216#endif // #ifndef LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H
217