ExplainOutputStyle.cpp

//===- ExplainOutputStyle.cpp --------------------------------- *- C++ --*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include"ExplainOutputStyle.h"

#include"StreamUtil.h"
#include"llvm-pdbutil.h"

#include"llvm/DebugInfo/CodeView/Formatters.h"
#include"llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h"
#include"llvm/DebugInfo/MSF/MappedBlockStream.h"
#include"llvm/DebugInfo/PDB/Native/DbiStream.h"
#include"llvm/DebugInfo/PDB/Native/FormatUtil.h"
#include"llvm/DebugInfo/PDB/Native/InfoStream.h"
#include"llvm/DebugInfo/PDB/Native/InputFile.h"
#include"llvm/DebugInfo/PDB/Native/NativeSession.h"
#include"llvm/DebugInfo/PDB/Native/PDBFile.h"
#include"llvm/DebugInfo/PDB/Native/RawTypes.h"
#include"llvm/Object/COFF.h"
#include"llvm/Support/BinaryByteStream.h"
#include"llvm/Support/BinaryStreamArray.h"
#include"llvm/Support/Error.h"

usingnamespacellvm;
usingnamespacellvm::codeview;
usingnamespacellvm::msf;
usingnamespacellvm::pdb;

ExplainOutputStyle::ExplainOutputStyle(InputFile &File, uint64_t FileOffset)
 : File(File), FileOffset(FileOffset), P(2, false, outs(), opts::Filters) {}

Error ExplainOutputStyle::dump() {
 P.formatLine("Explaining file offset {0} of file '{1}'.", FileOffset,
 File.getFilePath());

if (File.isPdb())
returnexplainPdbFile();

returnexplainBinaryFile();
}

Error ExplainOutputStyle::explainPdbFile() {
bool IsAllocated = explainPdbBlockStatus();
if (!IsAllocated)
returnError::success();

 AutoIndent Indent(P);
if (isPdbSuperBlock())
explainPdbSuperBlockOffset();
elseif (isPdbFpmBlock())
explainPdbFpmBlockOffset();
elseif (isPdbBlockMapBlock())
explainPdbBlockMapOffset();
elseif (isPdbStreamDirectoryBlock())
explainPdbStreamDirectoryOffset();
elseif (auto Index = getPdbBlockStreamIndex())
explainPdbStreamOffset(*Index);
else
explainPdbUnknownBlock();
returnError::success();
}

Error ExplainOutputStyle::explainBinaryFile() {
 std::unique_ptr<BinaryByteStream> Stream =
 std::make_unique<BinaryByteStream>(File.unknown().getBuffer(),
 llvm::support::little);
switch (opts::explain::InputType) {
case opts::explain::InputFileType::DBIStream: {
 DbiStream Dbi(std::move(Stream));
if (auto EC = Dbi.reload(nullptr))
return EC;
explainStreamOffset(Dbi, FileOffset);
break;
 }
case opts::explain::InputFileType::PDBStream: {
 InfoStream Info(std::move(Stream));
if (auto EC = Info.reload())
return EC;
explainStreamOffset(Info, FileOffset);
break;
 }
default:
llvm_unreachable("Invalid input file type!");
 }
returnError::success();
}

uint32_tExplainOutputStyle::pdbBlockIndex() const {
return FileOffset / File.pdb().getBlockSize();
}

uint32_tExplainOutputStyle::pdbBlockOffset() const {
uint64_t BlockStart = pdbBlockIndex() * File.pdb().getBlockSize();
assert(FileOffset >= BlockStart);
return FileOffset - BlockStart;
}

boolExplainOutputStyle::isPdbSuperBlock() const {
returnpdbBlockIndex() == 0;
}

boolExplainOutputStyle::isPdbFpm1() const {
return ((pdbBlockIndex() - 1) % File.pdb().getBlockSize() == 0);
}
boolExplainOutputStyle::isPdbFpm2() const {
return ((pdbBlockIndex() - 2) % File.pdb().getBlockSize() == 0);
}

boolExplainOutputStyle::isPdbFpmBlock() const {
returnisPdbFpm1() || isPdbFpm2();
}

boolExplainOutputStyle::isPdbBlockMapBlock() const {
returnpdbBlockIndex() == File.pdb().getBlockMapIndex();
}

boolExplainOutputStyle::isPdbStreamDirectoryBlock() const {
constauto &Layout = File.pdb().getMsfLayout();
returnllvm::is_contained(Layout.DirectoryBlocks, pdbBlockIndex());
}

Optional<uint32_t> ExplainOutputStyle::getPdbBlockStreamIndex() const {
constauto &Layout = File.pdb().getMsfLayout();
for (constauto &Entry : enumerate(Layout.StreamMap)) {
if (!llvm::is_contained(Entry.value(), pdbBlockIndex()))
continue;
return Entry.index();
 }
return None;
}

boolExplainOutputStyle::explainPdbBlockStatus() {
if (FileOffset >= File.pdb().getFileSize()) {
 P.formatLine("Address {0} is not in the file (file size = {1}).",
 FileOffset, File.pdb().getFileSize());
returnfalse;
 }
 P.formatLine("Block:Offset = {2:X-}:{1:X-4}.", FileOffset, pdbBlockOffset(),
pdbBlockIndex());

bool IsFree = File.pdb().getMsfLayout().FreePageMap[pdbBlockIndex()];
 P.formatLine("Address is in block {0} ({1}allocated).", pdbBlockIndex(),
 IsFree ? "un" : "");
return !IsFree;
}

#defineendof(Class, Field) (offsetof(Class, Field) + sizeof(Class::Field))

voidExplainOutputStyle::explainPdbSuperBlockOffset() {
 P.formatLine("This corresponds to offset {0} of the MSF super block, ",
pdbBlockOffset());
if (pdbBlockOffset() < endof(SuperBlock, MagicBytes))
 P.printLine("which is part of the MSF file magic.");
elseif (pdbBlockOffset() < endof(SuperBlock, BlockSize)) {
 P.printLine("which contains the block size of the file.");
 P.formatLine("The current value is {0}.",
uint32_t(File.pdb().getMsfLayout().SB->BlockSize));
 } elseif (pdbBlockOffset() < endof(SuperBlock, FreeBlockMapBlock)) {
 P.printLine("which contains the index of the FPM block (e.g. 1 or 2).");
 P.formatLine("The current value is {0}.",
uint32_t(File.pdb().getMsfLayout().SB->FreeBlockMapBlock));
 } elseif (pdbBlockOffset() < endof(SuperBlock, NumBlocks)) {
 P.printLine("which contains the number of blocks in the file.");
 P.formatLine("The current value is {0}.",
uint32_t(File.pdb().getMsfLayout().SB->NumBlocks));
 } elseif (pdbBlockOffset() < endof(SuperBlock, NumDirectoryBytes)) {
 P.printLine("which contains the number of bytes in the stream directory.");
 P.formatLine("The current value is {0}.",
uint32_t(File.pdb().getMsfLayout().SB->NumDirectoryBytes));
 } elseif (pdbBlockOffset() < endof(SuperBlock, Unknown1)) {
 P.printLine("whose purpose is unknown.");
 P.formatLine("The current value is {0}.",
uint32_t(File.pdb().getMsfLayout().SB->Unknown1));
 } elseif (pdbBlockOffset() < endof(SuperBlock, BlockMapAddr)) {
 P.printLine("which contains the file offset of the block map.");
 P.formatLine("The current value is {0}.",
uint32_t(File.pdb().getMsfLayout().SB->BlockMapAddr));
 } else {
assert(pdbBlockOffset() > sizeof(SuperBlock));
 P.printLine(
"which is outside the range of valid data for the super block.");
 }
}

static std::string toBinaryString(uint8_tByte) {
char Result[9] = {0};
for (int I = 0; I < 8; ++I) {
char C = (Byte & 1) ? '1' : '0';
 Result[I] = C;
Byte >>= 1;
 }
returnstd::string(Result);
}

voidExplainOutputStyle::explainPdbFpmBlockOffset() {
const MSFLayout &Layout = File.pdb().getMsfLayout();
uint32_t MainFpm = Layout.mainFpmBlock();
uint32_t AltFpm = Layout.alternateFpmBlock();

assert(isPdbFpmBlock());
uint32_t Fpm = isPdbFpm1() ? 1 : 2;
uint32_t FpmChunk = pdbBlockIndex() / File.pdb().getBlockSize();
assert((Fpm == MainFpm) || (Fpm == AltFpm));
 (void)AltFpm;
bool IsMain = (Fpm == MainFpm);
 P.formatLine("Address is in FPM{0} ({1} FPM)", Fpm, IsMain ? "Main" : "Alt");
uint32_t DescribedBlockStart =
8 * (FpmChunk * File.pdb().getBlockSize() + pdbBlockOffset());
if (DescribedBlockStart > File.pdb().getBlockCount()) {
 P.printLine("Address is in extraneous FPM space.");
return;
 }

 P.formatLine("Address describes the allocation status of blocks [{0},{1})",
 DescribedBlockStart, DescribedBlockStart + 8);
 ArrayRef<uint8_t> Bytes;
cantFail(File.pdb().getMsfBuffer().readBytes(FileOffset, 1, Bytes));
 P.formatLine("Status = {0} (Note: 0 = allocated, 1 = free)",
toBinaryString(Bytes[0]));
}

voidExplainOutputStyle::explainPdbBlockMapOffset() {
uint64_t BlockMapOffset = File.pdb().getBlockMapOffset();
uint32_t OffsetInBlock = FileOffset - BlockMapOffset;
 P.formatLine("Address is at offset {0} of the directory block list",
 OffsetInBlock);
}

staticuint32_tgetOffsetInStream(ArrayRef<support::ulittle32_t> StreamBlocks,
uint64_t FileOffset, uint32_t BlockSize) {
uint32_t BlockIndex = FileOffset / BlockSize;
uint32_t OffsetInBlock = FileOffset - BlockIndex * BlockSize;

auto Iter = llvm::find(StreamBlocks, BlockIndex);
assert(Iter != StreamBlocks.end());
uint32_t StreamBlockIndex = std::distance(StreamBlocks.begin(), Iter);
return StreamBlockIndex * BlockSize + OffsetInBlock;
}

voidExplainOutputStyle::explainPdbStreamOffset(uint32_t Stream) {
 SmallVector<StreamInfo, 12> Streams;
discoverStreamPurposes(File.pdb(), Streams);

assert(Stream <= Streams.size());
const StreamInfo &S = Streams[Stream];
constauto &Layout = File.pdb().getStreamLayout(Stream);
uint32_t StreamOff =
getOffsetInStream(Layout.Blocks, FileOffset, File.pdb().getBlockSize());
 P.formatLine("Address is at offset {0}/{1} of Stream {2} ({3}){4}.",
 StreamOff, Layout.Length, Stream, S.getLongName(),
 (StreamOff > Layout.Length) ? " in unused space" : "");
switch (S.getPurpose()) {
case StreamPurpose::DBI: {
 DbiStream &Dbi = cantFail(File.pdb().getPDBDbiStream());
explainStreamOffset(Dbi, StreamOff);
break;
 }
case StreamPurpose::PDB: {
 InfoStream &Info = cantFail(File.pdb().getPDBInfoStream());
explainStreamOffset(Info, StreamOff);
break;
 }
case StreamPurpose::IPI:
case StreamPurpose::TPI:
case StreamPurpose::ModuleStream:
case StreamPurpose::NamedStream:
default:
break;
 }
}

voidExplainOutputStyle::explainPdbStreamDirectoryOffset() {
auto DirectoryBlocks = File.pdb().getDirectoryBlockArray();
constauto &Layout = File.pdb().getMsfLayout();
uint32_t StreamOff =
getOffsetInStream(DirectoryBlocks, FileOffset, File.pdb().getBlockSize());
 P.formatLine("Address is at offset {0}/{1} of Stream Directory{2}.",
 StreamOff, uint32_t(Layout.SB->NumDirectoryBytes),
uint32_t(StreamOff > Layout.SB->NumDirectoryBytes)
 ? " in unused space"
 : "");
}

voidExplainOutputStyle::explainPdbUnknownBlock() {
 P.formatLine("Address has unknown purpose.");
}

template <typename T>
staticvoidprintStructField(LinePrinter &P, StringRef Label, T Value) {
 P.formatLine("which contains {0}.", Label);
 P.formatLine("The current value is {0}.", Value);
}

staticvoidexplainDbiHeaderOffset(LinePrinter &P, DbiStream &Dbi,
uint32_t Offset) {
const DbiStreamHeader *Header = Dbi.getHeader();
assert(Header != nullptr);

if (Offset < endof(DbiStreamHeader, VersionSignature))
printStructField(P, "the DBI Stream Version Signature",
int32_t(Header->VersionSignature));
elseif (Offset < endof(DbiStreamHeader, VersionHeader))
printStructField(P, "the DBI Stream Version Header",
uint32_t(Header->VersionHeader));
elseif (Offset < endof(DbiStreamHeader, Age))
printStructField(P, "the age of the DBI Stream", uint32_t(Header->Age));
elseif (Offset < endof(DbiStreamHeader, GlobalSymbolStreamIndex))
printStructField(P, "the index of the Global Symbol Stream",
uint16_t(Header->GlobalSymbolStreamIndex));
elseif (Offset < endof(DbiStreamHeader, BuildNumber))
printStructField(P, "the build number", uint16_t(Header->BuildNumber));
elseif (Offset < endof(DbiStreamHeader, PublicSymbolStreamIndex))
printStructField(P, "the index of the Public Symbol Stream",
uint16_t(Header->PublicSymbolStreamIndex));
elseif (Offset < endof(DbiStreamHeader, PdbDllVersion))
printStructField(P, "the version of mspdb.dll",
uint16_t(Header->PdbDllVersion));
elseif (Offset < endof(DbiStreamHeader, SymRecordStreamIndex))
printStructField(P, "the index of the Symbol Record Stream",
uint16_t(Header->SymRecordStreamIndex));
elseif (Offset < endof(DbiStreamHeader, PdbDllRbld))
printStructField(P, "the rbld of mspdb.dll", uint16_t(Header->PdbDllRbld));
elseif (Offset < endof(DbiStreamHeader, ModiSubstreamSize))
printStructField(P, "the size of the Module Info Substream",
int32_t(Header->ModiSubstreamSize));
elseif (Offset < endof(DbiStreamHeader, SecContrSubstreamSize))
printStructField(P, "the size of the Section Contribution Substream",
int32_t(Header->SecContrSubstreamSize));
elseif (Offset < endof(DbiStreamHeader, SectionMapSize))
printStructField(P, "the size of the Section Map Substream",
int32_t(Header->SectionMapSize));
elseif (Offset < endof(DbiStreamHeader, FileInfoSize))
printStructField(P, "the size of the File Info Substream",
int32_t(Header->FileInfoSize));
elseif (Offset < endof(DbiStreamHeader, TypeServerSize))
printStructField(P, "the size of the Type Server Map",
int32_t(Header->TypeServerSize));
elseif (Offset < endof(DbiStreamHeader, MFCTypeServerIndex))
printStructField(P, "the index of the MFC Type Server stream",
uint32_t(Header->MFCTypeServerIndex));
elseif (Offset < endof(DbiStreamHeader, OptionalDbgHdrSize))
printStructField(P, "the size of the Optional Debug Stream array",
int32_t(Header->OptionalDbgHdrSize));
elseif (Offset < endof(DbiStreamHeader, ECSubstreamSize))
printStructField(P, "the size of the Edit & Continue Substream",
int32_t(Header->ECSubstreamSize));
elseif (Offset < endof(DbiStreamHeader, Flags))
printStructField(P, "the DBI Stream flags", uint16_t(Header->Flags));
elseif (Offset < endof(DbiStreamHeader, MachineType))
printStructField(P, "the machine type", uint16_t(Header->MachineType));
elseif (Offset < endof(DbiStreamHeader, Reserved))
printStructField(P, "reserved data", uint32_t(Header->Reserved));
}

staticvoidexplainDbiModiSubstreamOffset(LinePrinter &P, DbiStream &Dbi,
uint32_t Offset) {
 VarStreamArray<DbiModuleDescriptor> ModuleDescriptors;
 BinaryStreamRef ModiSubstreamData = Dbi.getModiSubstreamData().StreamData;
 BinaryStreamReader Reader(ModiSubstreamData);

cantFail(Reader.readArray(ModuleDescriptors, ModiSubstreamData.getLength()));
auto Prev = ModuleDescriptors.begin();
assert(Prev.offset() == 0);
auto Current = Prev;
uint32_t Index = 0;
while (true) {
 Prev = Current;
 ++Current;
if (Current == ModuleDescriptors.end() || Offset < Current.offset())
break;
 ++Index;
 }

const DbiModuleDescriptor &Descriptor = *Prev;
 P.formatLine("which contains the descriptor for module {0} ({1}).", Index,
 Descriptor.getModuleName());
}

template <typename T>
staticvoiddontExplain(LinePrinter &Printer, T &Stream, uint32_t Offset) {}

template <typename T, typename SubstreamRangeT>
staticvoidexplainSubstreamOffset(LinePrinter &P, uint32_t OffsetInStream,
 T &Stream,
const SubstreamRangeT &Substreams) {
uint32_t SubOffset = OffsetInStream;
for (constauto &Entry : Substreams) {
if (Entry.Size <= 0)
continue;
uint32_t S = static_cast<uint32_t>(Entry.Size);
if (SubOffset < S) {
 P.formatLine("address is at offset {0}/{1} of the {2}.", SubOffset, S,
 Entry.Label);
 Entry.Explain(P, Stream, SubOffset);
return;
 }
 SubOffset -= S;
 }
}

voidExplainOutputStyle::explainStreamOffset(DbiStream &Dbi,
uint32_t OffsetInStream) {
 P.printLine("Within the DBI stream:");
 AutoIndent Indent(P);
const DbiStreamHeader *Header = Dbi.getHeader();
assert(Header != nullptr);

structSubstreamInfo {
int32_tSize;
 StringRef Label;
void (*Explain)(LinePrinter &, DbiStream &, uint32_t);
 } Substreams[] = {
 {sizeof(DbiStreamHeader), "DBI Stream Header", explainDbiHeaderOffset},
 {int32_t(Header->ModiSubstreamSize), "Module Info Substream",
 explainDbiModiSubstreamOffset},
 {int32_t(Header->SecContrSubstreamSize), "Section Contribution Substream",
 dontExplain<DbiStream>},
 {int32_t(Header->SectionMapSize), "Section Map", dontExplain<DbiStream>},
 {int32_t(Header->FileInfoSize), "File Info Substream",
 dontExplain<DbiStream>},
 {int32_t(Header->TypeServerSize), "Type Server Map Substream",
 dontExplain<DbiStream>},
 {int32_t(Header->ECSubstreamSize), "Edit & Continue Substream",
 dontExplain<DbiStream>},
 {int32_t(Header->OptionalDbgHdrSize), "Optional Debug Stream Array",
 dontExplain<DbiStream>},
 };

explainSubstreamOffset(P, OffsetInStream, Dbi, Substreams);
}

staticvoidexplainPdbStreamHeaderOffset(LinePrinter &P, InfoStream &Info,
uint32_t Offset) {
const InfoStreamHeader *Header = Info.getHeader();
assert(Header != nullptr);

if (Offset < endof(InfoStreamHeader, Version))
printStructField(P, "the PDB Stream Version Signature",
uint32_t(Header->Version));
elseif (Offset < endof(InfoStreamHeader, Signature))
printStructField(P, "the signature of the PDB Stream",
uint32_t(Header->Signature));
elseif (Offset < endof(InfoStreamHeader, Age))
printStructField(P, "the age of the PDB", uint32_t(Header->Age));
elseif (Offset < endof(InfoStreamHeader, Guid))
printStructField(P, "the guid of the PDB", fmt_guid(Header->Guid.Guid));
}

voidExplainOutputStyle::explainStreamOffset(InfoStream &Info,
uint32_t OffsetInStream) {
 P.printLine("Within the PDB stream:");
 AutoIndent Indent(P);

structSubstreamInfo {
uint32_tSize;
 StringRef Label;
void (*Explain)(LinePrinter &, InfoStream &, uint32_t);
 } Substreams[] = {{sizeof(InfoStreamHeader), "PDB Stream Header",
 explainPdbStreamHeaderOffset},
 {Info.getNamedStreamMapByteSize(), "Named Stream Map",
 dontExplain<InfoStream>},
 {Info.getStreamSize(), "PDB Feature Signatures",
 dontExplain<InfoStream>}};

explainSubstreamOffset(P, OffsetInStream, Info, Substreams);
}