1 //===- DWARFDebugMacro.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_DWARF_DWARFDEBUGMACRO_H
10 #define LLVM_DEBUGINFO_DWARF_DWARFDEBUGMACRO_H
11 
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
14 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
15 #include "llvm/Support/Error.h"
16 #include <cstdint>
17 
18 namespace llvm {
19 
20 class raw_ostream;
21 class DwarfStreamer;
22 
23 class DWARFDebugMacro {
24   friend DwarfStreamer;
25 
26   /// DWARFv5 section 6.3.1 Macro Information Header.
27   enum HeaderFlagMask {
28 #define HANDLE_MACRO_FLAG(ID, NAME) MACRO_##NAME = ID,
29 #include "llvm/BinaryFormat/Dwarf.def"
30   };
31   struct MacroHeader {
32     /// Macro version information number.
33     uint16_t Version = 0;
34 
35     /// The bits of the flags field are interpreted as a set of flags, some of
36     /// which may indicate that additional fields follow. The following flags,
37     /// beginning with the least significant bit, are defined:
38     /// offset_size_flag:
39     ///   If the offset_size_flag is zero, the header is for a 32-bit DWARF
40     ///   format macro section and all offsets are 4 bytes long; if it is one,
41     ///   the header is for a 64-bit DWARF format macro section and all offsets
42     ///   are 8 bytes long.
43     /// debug_line_offset_flag:
44     ///   If the debug_line_offset_flag is one, the debug_line_offset field (see
45     ///   below) is present. If zero, that field is omitted.
46     /// opcode_operands_table_flag:
47     ///   If the opcode_operands_table_flag is one, the opcode_operands_table
48     ///   field (see below) is present. If zero, that field is omitted.
49     uint8_t Flags = 0;
50 
51     /// debug_line_offset
52     ///   An offset in the .debug_line section of the beginning of the line
53     ///   number information in the containing compilation unit, encoded as a
54     ///   4-byte offset for a 32-bit DWARF format macro section and an 8-byte
55     ///   offset for a 64-bit DWARF format macro section.
56     uint64_t DebugLineOffset;
57 
58     /// Print the macro header from the debug_macro section.
59     void dumpMacroHeader(raw_ostream &OS) const;
60 
61     /// Parse the debug_macro header.
62     Error parseMacroHeader(DWARFDataExtractor Data, uint64_t *Offset);
63 
64     /// Get the DWARF format according to the flags.
65     dwarf::DwarfFormat getDwarfFormat() const;
66 
67     /// Get the size of a reference according to the DWARF format.
68     uint8_t getOffsetByteSize() const;
69   };
70 
71   /// A single macro entry within a macro list.
72   struct Entry {
73     /// The type of the macro entry.
74     uint32_t Type;
75     union {
76       /// The source line where the macro is defined.
77       uint64_t Line;
78       /// Vendor extension constant value.
79       uint64_t ExtConstant;
80       /// Macro unit import offset.
81       uint64_t ImportOffset;
82     };
83 
84     union {
85       /// The string (name, value) of the macro entry.
86       const char *MacroStr;
87       // An unsigned integer indicating the identity of the source file.
88       uint64_t File;
89       /// Vendor extension string.
90       const char *ExtStr;
91     };
92   };
93 
94   struct MacroList {
95     // A value 0 in the `Header.Version` field indicates that we're parsing
96     // a macinfo[.dwo] section which doesn't have header itself, hence
97     // for that case other fields in the `Header` are uninitialized.
98     MacroHeader Header;
99     SmallVector<Entry, 4> Macros;
100     uint64_t Offset;
101 
102     /// Whether or not this is a .debug_macro section.
103     bool IsDebugMacro;
104   };
105 
106   /// A list of all the macro entries in the debug_macinfo section.
107   std::vector<MacroList> MacroLists;
108 
109 public:
110   DWARFDebugMacro() = default;
111 
112   /// Print the macro list found within the debug_macinfo/debug_macro section.
113   void dump(raw_ostream &OS) const;
114 
115   Error parseMacro(DWARFUnitVector::compile_unit_range Units,
116                    DataExtractor StringExtractor,
117                    DWARFDataExtractor MacroData) {
118     return parseImpl(Units, StringExtractor, MacroData, /*IsMacro=*/true);
119   }
120 
121   Error parseMacinfo(DWARFDataExtractor MacroData) {
122     return parseImpl(std::nullopt, std::nullopt, MacroData, /*IsMacro=*/false);
123   }
124 
125   /// Return whether the section has any entries.
126   bool empty() const { return MacroLists.empty(); }
127 
128   bool hasEntryForOffset(uint64_t Offset) const {
129     for (const MacroList &List : MacroLists)
130       if (Offset == List.Offset)
131         return true;
132 
133     return false;
134   }
135 
136 private:
137   /// Parse the debug_macinfo/debug_macro section accessible via the 'MacroData'
138   /// parameter.
139   Error parseImpl(std::optional<DWARFUnitVector::compile_unit_range> Units,
140                   std::optional<DataExtractor> StringExtractor,
141                   DWARFDataExtractor Data, bool IsMacro);
142 };
143 
144 } // end namespace llvm
145 
146 #endif // LLVM_DEBUGINFO_DWARF_DWARFDEBUGMACRO_H
147