1 //===- DebugSubsectionRecord.cpp ------------------------------------------===//
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 #include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
10 #include "llvm/DebugInfo/CodeView/CodeView.h"
11 #include "llvm/DebugInfo/CodeView/DebugSubsection.h"
12 #include "llvm/Support/BinaryStreamReader.h"
13 #include "llvm/Support/BinaryStreamWriter.h"
14 #include "llvm/Support/Error.h"
15 #include "llvm/Support/MathExtras.h"
16 #include <cassert>
17 #include <cstdint>
18 
19 using namespace llvm;
20 using namespace llvm::codeview;
21 
22 DebugSubsectionRecord::DebugSubsectionRecord() = default;
23 
24 DebugSubsectionRecord::DebugSubsectionRecord(DebugSubsectionKind Kind,
25                                              BinaryStreamRef Data)
26     : Kind(Kind), Data(Data) {}
27 
28 Error DebugSubsectionRecord::initialize(BinaryStreamRef Stream,
29                                         DebugSubsectionRecord &Info) {
30   const DebugSubsectionHeader *Header;
31   BinaryStreamReader Reader(Stream);
32   if (auto EC = Reader.readObject(Header))
33     return EC;
34 
35   DebugSubsectionKind Kind =
36       static_cast<DebugSubsectionKind>(uint32_t(Header->Kind));
37   if (auto EC = Reader.readStreamRef(Info.Data, Header->Length))
38     return EC;
39   Info.Kind = Kind;
40   return Error::success();
41 }
42 
43 uint32_t DebugSubsectionRecord::getRecordLength() const {
44   return sizeof(DebugSubsectionHeader) + Data.getLength();
45 }
46 
47 DebugSubsectionKind DebugSubsectionRecord::kind() const { return Kind; }
48 
49 BinaryStreamRef DebugSubsectionRecord::getRecordData() const { return Data; }
50 
51 DebugSubsectionRecordBuilder::DebugSubsectionRecordBuilder(
52     std::shared_ptr<DebugSubsection> Subsection)
53     : Subsection(std::move(Subsection)) {}
54 
55 DebugSubsectionRecordBuilder::DebugSubsectionRecordBuilder(
56     const DebugSubsectionRecord &Contents)
57     : Contents(Contents) {}
58 
59 uint32_t DebugSubsectionRecordBuilder::calculateSerializedLength() const {
60   uint32_t DataSize = Subsection ? Subsection->calculateSerializedSize()
61                                  : Contents.getRecordData().getLength();
62   // The length of the entire subsection is always padded to 4 bytes,
63   // regardless of the container kind.
64   return sizeof(DebugSubsectionHeader) + alignTo(DataSize, 4);
65 }
66 
67 Error DebugSubsectionRecordBuilder::commit(BinaryStreamWriter &Writer,
68                                            CodeViewContainer Container) const {
69   assert(Writer.getOffset() % alignOf(Container) == 0 &&
70          "Debug Subsection not properly aligned");
71 
72   DebugSubsectionHeader Header;
73   Header.Kind = uint32_t(Subsection ? Subsection->kind() : Contents.kind());
74   // The value written into the Header's Length field is only padded to the
75   // container's alignment
76   uint32_t DataSize = Subsection ? Subsection->calculateSerializedSize()
77                                  : Contents.getRecordData().getLength();
78   Header.Length = alignTo(DataSize, alignOf(Container));
79 
80   if (auto EC = Writer.writeObject(Header))
81     return EC;
82   if (Subsection) {
83     if (auto EC = Subsection->commit(Writer))
84       return EC;
85   } else {
86     if (auto EC = Writer.writeStreamRef(Contents.getRecordData()))
87       return EC;
88   }
89   if (auto EC = Writer.padToAlignment(4))
90     return EC;
91 
92   return Error::success();
93 }
94