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