1 //===- CVRecord.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_CODEVIEW_CVRECORD_H
10 #define LLVM_DEBUGINFO_CODEVIEW_CVRECORD_H
11 
12 #include "llvm/ADT/ArrayRef.h"
13 #include "llvm/ADT/Optional.h"
14 #include "llvm/DebugInfo/CodeView/CodeView.h"
15 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
16 #include "llvm/DebugInfo/CodeView/RecordSerialization.h"
17 #include "llvm/Support/BinaryStreamReader.h"
18 #include "llvm/Support/BinaryStreamRef.h"
19 #include "llvm/Support/Endian.h"
20 #include "llvm/Support/Error.h"
21 #include <cstdint>
22 
23 namespace llvm {
24 
25 namespace codeview {
26 
27 /// CVRecord is a fat pointer (base + size pair) to a symbol or type record.
28 /// Carrying the size separately instead of trusting the size stored in the
29 /// record prefix provides some extra safety and flexibility.
30 template <typename Kind> class CVRecord {
31 public:
32   CVRecord() = default;
33 
34   CVRecord(ArrayRef<uint8_t> Data) : RecordData(Data) {}
35 
36   CVRecord(const RecordPrefix *P, size_t Size)
37       : RecordData(reinterpret_cast<const uint8_t *>(P), Size) {}
38 
39   bool valid() const { return kind() != Kind(0); }
40 
41   uint32_t length() const { return RecordData.size(); }
42 
43   Kind kind() const {
44     if (RecordData.size() < sizeof(RecordPrefix))
45       return Kind(0);
46     return static_cast<Kind>(static_cast<uint16_t>(
47         reinterpret_cast<const RecordPrefix *>(RecordData.data())->RecordKind));
48   }
49 
50   ArrayRef<uint8_t> data() const { return RecordData; }
51 
52   StringRef str_data() const {
53     return StringRef(reinterpret_cast<const char *>(RecordData.data()),
54                      RecordData.size());
55   }
56 
57   ArrayRef<uint8_t> content() const {
58     return RecordData.drop_front(sizeof(RecordPrefix));
59   }
60 
61   ArrayRef<uint8_t> RecordData;
62 };
63 
64 // There are two kinds of codeview records: type and symbol records.
65 using CVType = CVRecord<TypeLeafKind>;
66 using CVSymbol = CVRecord<SymbolKind>;
67 
68 template <typename Record, typename Func>
69 Error forEachCodeViewRecord(ArrayRef<uint8_t> StreamBuffer, Func F) {
70   while (!StreamBuffer.empty()) {
71     if (StreamBuffer.size() < sizeof(RecordPrefix))
72       return make_error<CodeViewError>(cv_error_code::corrupt_record);
73 
74     const RecordPrefix *Prefix =
75         reinterpret_cast<const RecordPrefix *>(StreamBuffer.data());
76 
77     size_t RealLen = Prefix->RecordLen + 2;
78     if (StreamBuffer.size() < RealLen)
79       return make_error<CodeViewError>(cv_error_code::corrupt_record);
80 
81     ArrayRef<uint8_t> Data = StreamBuffer.take_front(RealLen);
82     StreamBuffer = StreamBuffer.drop_front(RealLen);
83 
84     Record R(Data);
85     if (auto EC = F(R))
86       return EC;
87   }
88   return Error::success();
89 }
90 
91 /// Read a complete record from a stream at a random offset.
92 template <typename Kind>
93 inline Expected<CVRecord<Kind>> readCVRecordFromStream(BinaryStreamRef Stream,
94                                                        uint32_t Offset) {
95   const RecordPrefix *Prefix = nullptr;
96   BinaryStreamReader Reader(Stream);
97   Reader.setOffset(Offset);
98 
99   if (auto EC = Reader.readObject(Prefix))
100     return std::move(EC);
101   if (Prefix->RecordLen < 2)
102     return make_error<CodeViewError>(cv_error_code::corrupt_record);
103 
104   Reader.setOffset(Offset);
105   ArrayRef<uint8_t> RawData;
106   if (auto EC = Reader.readBytes(RawData, Prefix->RecordLen + sizeof(uint16_t)))
107     return std::move(EC);
108   return codeview::CVRecord<Kind>(RawData);
109 }
110 
111 } // end namespace codeview
112 
113 template <typename Kind>
114 struct VarStreamArrayExtractor<codeview::CVRecord<Kind>> {
115   Error operator()(BinaryStreamRef Stream, uint32_t &Len,
116                    codeview::CVRecord<Kind> &Item) {
117     auto ExpectedRec = codeview::readCVRecordFromStream<Kind>(Stream, 0);
118     if (!ExpectedRec)
119       return ExpectedRec.takeError();
120     Item = *ExpectedRec;
121     Len = ExpectedRec->length();
122     return Error::success();
123   }
124 };
125 
126 namespace codeview {
127 using CVSymbolArray = VarStreamArray<CVSymbol>;
128 using CVTypeArray = VarStreamArray<CVType>;
129 using CVTypeRange = iterator_range<CVTypeArray::Iterator>;
130 } // namespace codeview
131 
132 } // end namespace llvm
133 
134 #endif // LLVM_DEBUGINFO_CODEVIEW_CVRECORD_H
135