1 //===- InlineInfo.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_INLINEINFO_H
10 #define LLVM_DEBUGINFO_GSYM_INLINEINFO_H
11 
12 #include "llvm/ADT/Optional.h"
13 #include "llvm/DebugInfo/GSYM/ExtractRanges.h"
14 #include "llvm/DebugInfo/GSYM/LineEntry.h"
15 #include "llvm/DebugInfo/GSYM/LookupResult.h"
16 #include "llvm/Support/Error.h"
17 #include <stdint.h>
18 #include <vector>
19 
20 namespace llvm {
21 class raw_ostream;
22 
23 namespace gsym {
24 
25 class GsymReader;
26 /// Inline information stores the name of the inline function along with
27 /// an array of address ranges. It also stores the call file and call line
28 /// that called this inline function. This allows us to unwind inline call
29 /// stacks back to the inline or concrete function that called this
30 /// function. Inlined functions contained in this function are stored in the
31 /// "Children" variable. All address ranges must be sorted and all address
32 /// ranges of all children must be contained in the ranges of this function.
33 /// Any clients that encode information will need to ensure the ranges are
34 /// all contined correctly or lookups could fail. Add ranges in these objects
35 /// must be contained in the top level FunctionInfo address ranges as well.
36 ///
37 /// ENCODING
38 ///
39 /// When saved to disk, the inline info encodes all ranges to be relative to
40 /// a parent address range. This will be the FunctionInfo's start address if
41 /// the InlineInfo is directly contained in a FunctionInfo, or a the start
42 /// address of the containing parent InlineInfo's first "Ranges" member. This
43 /// allows address ranges to be efficiently encoded using ULEB128 encodings as
44 /// we encode the offset and size of each range instead of full addresses. This
45 /// also makes any encoded addresses easy to relocate as we just need to
46 /// relocate the FunctionInfo's start address.
47 ///
48 /// - The AddressRanges member "Ranges" is encoded using an appropriate base
49 ///   address as described above.
50 /// - UINT8 boolean value that specifies if the InlineInfo object has children.
51 /// - UINT32 string table offset that points to the name of the inline
52 ///   function.
53 /// - ULEB128 integer that specifies the file of the call site that called
54 ///   this function.
55 /// - ULEB128 integer that specifies the source line of the call site that
56 ///   called this function.
57 /// - if this object has children, enocode each child InlineInfo using the
58 ///   the first address range's start address as the base address.
59 ///
60 struct InlineInfo {
61 
62   uint32_t Name; ///< String table offset in the string table.
63   uint32_t CallFile; ///< 1 based file index in the file table.
64   uint32_t CallLine; ///< Source line number.
65   AddressRanges Ranges;
66   std::vector<InlineInfo> Children;
67   InlineInfo() : Name(0), CallFile(0), CallLine(0) {}
68   void clear() {
69     Name = 0;
70     CallFile = 0;
71     CallLine = 0;
72     Ranges.clear();
73     Children.clear();
74   }
75   bool isValid() const { return !Ranges.empty(); }
76 
77   using InlineArray = std::vector<const InlineInfo *>;
78 
79   /// Lookup a single address within the inline info data.
80   ///
81   /// Clients have the option to decode an entire InlineInfo object (using
82   /// InlineInfo::decode() ) or just find the matching inline info using this
83   /// function. The benefit of using this function is that only the information
84   /// needed for the lookup will be extracted, other info can be skipped and
85   /// parsing can stop as soon as the deepest match is found. This allows
86   /// symbolication tools to be fast and efficient and avoid allocation costs
87   /// when doing lookups.
88   ///
89   /// This function will augment the SourceLocations array \a SrcLocs with any
90   /// inline information that pertains to \a Addr. If no inline information
91   /// exists for \a Addr, then \a SrcLocs will be left untouched. If there is
92   /// inline information for \a Addr, then \a SrcLocs will be modifiied to
93   /// contain the deepest most inline function's SourceLocation at index zero
94   /// in the array and proceed up the the concrete function source file and
95   /// line at the end of the array.
96   ///
97   /// \param GR The GSYM reader that contains the string and file table that
98   /// will be used to fill in the source locations.
99   ///
100   /// \param Data The binary stream to read the data from. This object must
101   /// have the data for the LineTable object starting at offset zero. The data
102   /// can contain more data than needed.
103   ///
104   /// \param BaseAddr The base address to use when decoding the line table.
105   /// This will be the FunctionInfo's start address and will be used to
106   /// decode the correct addresses for the inline information.
107   ///
108   /// \param Addr The address to lookup.
109   ///
110   /// \param SrcLocs The inline source locations that matches \a Addr. This
111   ///                array must be initialized with the matching line entry
112   ///                from the line table upon entry. The name of the concrete
113   ///                function must be supplied since it will get pushed to
114   ///                the last SourceLocation entry and the inline information
115   ///                will fill in the source file and line from the inline
116   ///                information.
117   ///
118   /// \returns An error if the inline information is corrupt, or
119   ///          Error::success() for all other cases, even when no information
120   ///          is added to \a SrcLocs.
121   static llvm::Error lookup(const GsymReader &GR, DataExtractor &Data,
122                             uint64_t BaseAddr, uint64_t Addr,
123                             SourceLocations &SrcLocs);
124 
125   /// Lookup an address in the InlineInfo object
126   ///
127   /// This function is used to symbolicate an inline call stack and can
128   /// turn one address in the program into one or more inline call stacks
129   /// and have the stack trace show the original call site from
130   /// non-inlined code.
131   ///
132   /// \param Addr the address to lookup
133   ///
134   /// \returns optional vector of InlineInfo objects that describe the
135   /// inline call stack for a given address, false otherwise.
136   llvm::Optional<InlineArray> getInlineStack(uint64_t Addr) const;
137 
138   /// Decode an InlineInfo object from a binary data stream.
139   ///
140   /// \param Data The binary stream to read the data from. This object must
141   /// have the data for the InlineInfo object starting at offset zero. The data
142   /// can contain more data than needed.
143   ///
144   /// \param BaseAddr The base address to use when decoding all address ranges.
145   /// This will be the FunctionInfo's start address if this object is directly
146   /// contained in a FunctionInfo object, or the start address of the first
147   /// address range in an InlineInfo object of this object is a child of
148   /// another InlineInfo object.
149   /// \returns An InlineInfo or an error describing the issue that was
150   /// encountered during decoding.
151   static llvm::Expected<InlineInfo> decode(DataExtractor &Data,
152                                            uint64_t BaseAddr);
153 
154   /// Encode this InlineInfo object into FileWriter stream.
155   ///
156   /// \param O The binary stream to write the data to at the current file
157   /// position.
158   ///
159   /// \param BaseAddr The base address to use when encoding all address ranges.
160   /// This will be the FunctionInfo's start address if this object is directly
161   /// contained in a FunctionInfo object, or the start address of the first
162   /// address range in an InlineInfo object of this object is a child of
163   /// another InlineInfo object.
164   ///
165   /// \returns An error object that indicates success or failure or the
166   /// encoding process.
167   llvm::Error encode(FileWriter &O, uint64_t BaseAddr) const;
168 };
169 
170 inline bool operator==(const InlineInfo &LHS, const InlineInfo &RHS) {
171   return LHS.Name == RHS.Name && LHS.CallFile == RHS.CallFile &&
172          LHS.CallLine == RHS.CallLine && LHS.Ranges == RHS.Ranges &&
173          LHS.Children == RHS.Children;
174 }
175 
176 raw_ostream &operator<<(raw_ostream &OS, const InlineInfo &FI);
177 
178 } // namespace gsym
179 } // namespace llvm
180 
181 #endif // LLVM_DEBUGINFO_GSYM_INLINEINFO_H
182