1 //===- DebugSubsectionRecord.cpp ------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
11 #include "llvm/DebugInfo/CodeView/CodeView.h"
12 #include "llvm/DebugInfo/CodeView/DebugSubsection.h"
13 #include "llvm/Support/BinaryStreamReader.h"
14 #include "llvm/Support/BinaryStreamWriter.h"
15 #include "llvm/Support/Error.h"
16 #include "llvm/Support/MathExtras.h"
17 #include <algorithm>
18 #include <cassert>
19 #include <cstdint>
20 
21 using namespace llvm;
22 using namespace llvm::codeview;
23 
24 DebugSubsectionRecord::DebugSubsectionRecord() = default;
25 
26 DebugSubsectionRecord::DebugSubsectionRecord(DebugSubsectionKind Kind,
27                                              BinaryStreamRef Data,
28                                              CodeViewContainer Container)
29     : Container(Container), Kind(Kind), Data(Data) {}
30 
31 Error DebugSubsectionRecord::initialize(BinaryStreamRef Stream,
32                                         DebugSubsectionRecord &Info,
33                                         CodeViewContainer Container) {
34   const DebugSubsectionHeader *Header;
35   BinaryStreamReader Reader(Stream);
36   if (auto EC = Reader.readObject(Header))
37     return EC;
38 
39   DebugSubsectionKind Kind =
40       static_cast<DebugSubsectionKind>(uint32_t(Header->Kind));
41   if (auto EC = Reader.readStreamRef(Info.Data, Header->Length))
42     return EC;
43   Info.Container = Container;
44   Info.Kind = Kind;
45   return Error::success();
46 }
47 
48 uint32_t DebugSubsectionRecord::getRecordLength() const {
49   return sizeof(DebugSubsectionHeader) + Data.getLength();
50 }
51 
52 DebugSubsectionKind DebugSubsectionRecord::kind() const { return Kind; }
53 
54 BinaryStreamRef DebugSubsectionRecord::getRecordData() const { return Data; }
55 
56 DebugSubsectionRecordBuilder::DebugSubsectionRecordBuilder(
57     std::shared_ptr<DebugSubsection> Subsection, CodeViewContainer Container)
58     : Subsection(std::move(Subsection)), Container(Container) {}
59 
60 DebugSubsectionRecordBuilder::DebugSubsectionRecordBuilder(
61     const DebugSubsectionRecord &Contents, CodeViewContainer Container)
62     : Contents(Contents), Container(Container) {}
63 
64 uint32_t DebugSubsectionRecordBuilder::calculateSerializedLength() {
65   uint32_t DataSize = Subsection ? Subsection->calculateSerializedSize()
66                                  : Contents.getRecordData().getLength();
67   // The length of the entire subsection is always padded to 4 bytes,
68   // regardless of the container kind.
69   return sizeof(DebugSubsectionHeader) + alignTo(DataSize, 4);
70 }
71 
72 Error DebugSubsectionRecordBuilder::commit(BinaryStreamWriter &Writer) const {
73   assert(Writer.getOffset() % alignOf(Container) == 0 &&
74          "Debug Subsection not properly aligned");
75 
76   DebugSubsectionHeader Header;
77   Header.Kind = uint32_t(Subsection ? Subsection->kind() : Contents.kind());
78   // The value written into the Header's Length field is only padded to the
79   // container's alignment
80   uint32_t DataSize = Subsection ? Subsection->calculateSerializedSize()
81                                  : Contents.getRecordData().getLength();
82   Header.Length = alignTo(DataSize, alignOf(Container));
83 
84   if (auto EC = Writer.writeObject(Header))
85     return EC;
86   if (Subsection) {
87     if (auto EC = Subsection->commit(Writer))
88       return EC;
89   } else {
90     if (auto EC = Writer.writeStreamRef(Contents.getRecordData()))
91       return EC;
92   }
93   if (auto EC = Writer.padToAlignment(4))
94     return EC;
95 
96   return Error::success();
97 }
98