Fix Bug 30978 by emitting cv file checksums.

[ecbeckmann]

Summary

The checksums had already been placed in the IR, this patch allows
MCCodeView to actually write it out to an MCStreamer.

[ecbeckmann]

Rebase

[ecbeckmann]

tests

[ecbeckmann]

Some more testing changes.

[zturner]

Try to be more careful so as not to submit testing code / comments etc in uploaded patches. Reasons like this are why I prefer using a debugger instead of printf debugging :)

llvm/include/llvm/IR/DebugInfoMetadata.h

476–481 ↗

(On Diff #114116)

If you're going to make it an enum class, then it doesn't need the CSK prefix in the name, since you have to write ChecksumKind anyway. I wouldn't suggest churning the code to change the names everywhere it's used, so instead maybe just leave this as a regular enum. It's already scoped to DIFile anyway, so there's no risk of namespace pollution.

llvm/include/llvm/MC/MCCodeView.h

297–302

Any reason this isn't just:

struct FileInfo {
  StringRef Name;
  StringRef Checksum;
  ChecksumKind Kind;
};

SmallVector<FileInfo> Files;

having a StringMap seems unnecessary if we're already iterating a linear container anyway

llvm/lib/DebugInfo/CodeView/DebugChecksumsSubsection.cpp

53 ↗

(On Diff #114116)

Delete

llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp

32 ↗

(On Diff #114116)

Delete

38 ↗

(On Diff #114116)

Delete

44 ↗

(On Diff #114116)

Delete

llvm/lib/MC/MCCodeView.cpp

188–200

What is this? A bunch of code commented out, and then emitting a bunch of magic numbers?

llvm/tools/llvm-readobj/COFFDumper.cpp

927 ↗

(On Diff #114116)

Delete

929 ↗

(On Diff #114116)

Delete

1088 ↗

(On Diff #114116)

Delete

1090 ↗

(On Diff #114116)

Delete

[rnk]

llvm/lib/MC/MCCodeView.cpp

415–417

We shouldn't assume all DIFiles have MD5 checksums, we'll need some way to know the filechecksum table offset.

We should probably implement this FIXME:

// FIXME: We should store the string table offset of the filename, rather than
// the filename itself for efficiency.
Filename = addToStringTable(Filename);
Filenames[Idx] = Filename;

We should do that by making FIlenames a vector of two integers: the offset of the file in the file checksum table, and the offset of the filename in the string table.

All the places where we do 8 * (FileId - 1) we would rewrite to use Filenames[FileId - 1].ChecksumTableOffset.

[ecbeckmann]

Use MCFixup

[ecbeckmann]

Imprved?

[ecbeckmann]

Everything works finally.

[ecbeckmann]

llvm/include/llvm/MC/MCCodeView.h

283

remove

296

Just one comment says:

Array storing file information. Each tuple contains the string table offset, a symbol representing the file table offset, and a set flag.

301

remove

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

701

remove this comment

703

remove junk here too

llvm/lib/DebugInfo/CodeView/DebugChecksumsSubsection.cpp

53 ↗

(On Diff #114469)

remove

llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp

32 ↗

(On Diff #114469)

remove

39 ↗

(On Diff #114469)

remove

45 ↗

(On Diff #114469)

remove

[ecbeckmann]

llvm/lib/MC/MCCodeView.cpp

49

remove

60

remove comment

131

combine this all into one line

132

Don't reassign to S and just directly use Ret.first

146

add a comment explaining this function

147

remove

153

remove spaces here

159

remove these

165

+=4 for the string table offset

168

+1 for size, +1 for kind, +2 to align (maybe just replace that with alignTo for clarity)

171

remove logging, more comments to explain offset

174

add comment explaining that, since the checksum section has been emitted, we can assume the offsets have been finalized so we can assign them.

183

update this comment

189

remove these

199

yes remove this

203

add comment to explain, how it needs to use a MCFixup provided by EmitValueImpl

215

remove

218

create a temporary symbol to hold the offset once it is calculated

225

remove

240

a

372

r

415

change this comment

llvm/lib/MC/MCObjectStreamer.cpp

144 ↗

(On Diff #114469)

r

llvm/lib/MC/MCParser/AsmParser.cpp

3455

should be lower case for consistency

llvm/lib/MC/WinCOFFObjectWriter.cpp

725 ↗

(On Diff #114469)

r

llvm/tools/llvm-readobj/COFFDumper.cpp

910 ↗

(On Diff #114469)

r these

1020 ↗

(On Diff #114469)

r

1106 ↗

(On Diff #114469)

not needed

[ecbeckmann]

Make this entire thing easier to follow and understand.

llvm/lib/MC/MCCodeView.cpp

57

This is confusing to read, make it more intuitive

[ecbeckmann]

Fortunately this seems to work whether generating assembly or object

[ecbeckmann]

Why do we have to add placeholders for the checksum offsets? Aren't they just added in order, one after another?

Actually, the implementation of addFile hasn't assumed it is done in order, and you can actually add random fileNo's whenever you want. Therefore, we shouldn't assume they are always done in order, and we should allow for the case where we don't yet know the checksum offset.

[ecbeckmann]

Add checksum offset directive.

[ecbeckmann]

Restructrue, create real symbol not temp.

[ecbeckmann]

Remove errant errors.

[ecbeckmann]

Format

[ecbeckmann]

llvm/include/llvm/IR/DebugInfoMetadata.h

476–481 ↗

(On Diff #114116)

Unfortunately I need the actual enum values to correspond exactly to the checksum types flag integer values actually present in the codeview section, hence the strongly typed enum class. This is important because I will now be emitting the ChecksumKind as assembly directives as well as directly into the binary.

llvm/include/llvm/MC/MCCodeView.h

297–302

Yes, combined all this info into one vector. It's still useful to have a StringMap because we want to check if a filename is already used before making a new entry.

[ecbeckmann]

Reformat

[ecbeckmann]

Reformat.

[ecbeckmann]

llvm/lib/MC/MCCodeView.cpp

188–200

It was all debugging code that was unintended for review. Please disregard. Sorry again for not making this patch private to begin with.

415–417

Filenames renamed to Files, which is now a vector of a massive structure containing all offset and checksum information.

[ecbeckmann]

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

685

Update this FIXME to say that we do provide checksum file info, and what VS uses this for.

[rnk]

llvm/lib/MC/MCCodeView.cpp

161

I don't think you want to do this, this leaks the internal MCSymbol (file1, etc) to the assembler. Nothing in the assembly defines file1, so the assembly isn't very readable.

llvm/test/DebugInfo/COFF/inlining.ll

52 ↗

(On Diff #115274)

What I had in mind was that we'd add a directive like .cv_filechecksum_offset <fileid> and MCCodeView.cpp would internally implement it without leaking any labels to the caller. We could use a label difference of two symbols to implement the offset computation, but any symbols shouldn't leak out to the assembler.

[probinson]

llvm/include/llvm/IR/DebugInfoMetadata.h

476–481 ↗

(On Diff #114116)

If you need the enums to have specific values, e.g. because those values end up in the object file (hard to tell here but I think that's what you are saying), you should set the enum values explicitly. This documents the exact values you need (even if they happen to be sequential at the moment). Making it an enum class doesn't get you that.

llvm/lib/IR/DebugInfoMetadata.cpp

357 ↗

(On Diff #115274)

If you require exact correspondence between an enum and some array of strings, we usually do that with a .def file and macros. See for example Dwarf.def. As it is, the association between this array and the ChecksumKind values is implied rather than explicit. Safer to be explicit.

[rnk]

llvm/lib/MC/MCCodeView.cpp

67

Use MCContext::createTempSymbol to make sure these don't show up in the .obj symbol table.

[ecbeckmann]

Don't leak symbol into assembler, remove enum class, use createTempSymbol.

[ecbeckmann]

llvm/include/llvm/IR/DebugInfoMetadata.h

476–481 ↗

(On Diff #114116)

Remove enum class to explicitly define values.

llvm/lib/IR/DebugInfoMetadata.cpp

357 ↗

(On Diff #115274)

Okay this should probably be addressed in another patch as this patch did not introduce the array.

llvm/lib/MC/MCCodeView.cpp

161

Instead of emitting the symbol, we will emit the .cv_filechecksumoffset <fileno> directive.

[ecbeckmann]

Some formatting fixes.

[ecbeckmann]

Removed some last unnecessary changes.

[probinson]

A few minor commentary points; nothing huge. I've been looking at this mainly with the thought of having to do something similar for DWARF 5 eventually, but it seems likely there won't be a lot to leverage as CodeView and DWARF appear to associate the hashes with files pretty differently. Oh well.

llvm/include/llvm/IR/DebugInfoMetadata.h

476–481 ↗

(On Diff #114116)

And maybe a comment that these end up in the object file, so some well-meaning person doesn't come a long later and remove the "unnecessary" explicit values.

llvm/include/llvm/MC/MCStreamer.h

735

As long as you're changing the comment anyway, please remove the \brief.

777

Remove \brief.

[ecbeckmann]

llvm/test/DebugInfo/COFF/inlining.ll

52 ↗

(On Diff #115274)

implemented as such

[rnk]

Thanks, looks good!

llvm/include/llvm/MC/MCCodeView.h

299–300

Generally, if the comment describing the variable doesn't fit on one line, consider moving it before the variable. Then we won't end up with this awkard split after the *.

[ecbeckmann]

Changed some comments.

[ecbeckmann]

Updated comment formatting.

llvm/include/llvm/MC/MCCodeView.h

 
 /// Holds state from .cv_file and .cv_loc directives for later emission.
 class CodeViewContext {
 public:
   CodeViewContext();
   ~CodeViewContext();
 
   bool isValidFileNumber(unsigned FileNumber) const;
-  bool addFile(unsigned FileNumber, StringRef Filename);
+  bool addFile(unsigned FileNumber, StringRef Filename, StringRef Checksum, uint8_t ChecksumKind);
   ArrayRef<StringRef> getFilenames() { return Filenames; }
 
   /// Records the function id of a normal function. Returns false if the
   /// function id has already been used, and true otherwise.
   bool recordFunctionId(unsigned FuncId);
 
   /// Records the function id of an inlined call site. Records the "inlined at"
   /// location info of the call site, including what function or inlined call

 
 private:
   /// The current CodeView line information from the last .cv_loc directive.
   MCCVLoc CurrentCVLoc = MCCVLoc(0, 0, 0, 0, false, true);
   bool CVLocSeen = false;
 
   /// Map from string to string table offset.
   StringMap<unsigned> StringTable;
 
   /// The fragment that ultimately holds our strings.
   MCDataFragment *StrTabFragment = nullptr;
   bool InsertedStrTabFragment = false;
 
   MCDataFragment *getStringTableFragment();
 
   /// Add something to the string table.
   StringRef addToStringTable(StringRef S);
 
   /// Get a string table offset.
   unsigned getStringTableOffset(StringRef S);
 
   /// An array of absolute paths. Eventually this may include the file checksum.
   SmallVector<StringRef, 4> Filenames;
 
+  // Map from filename to checksum.
+  StringMap<std::pair<StringRef, uint8_t>> Checksums;
+
   /// The offset of the first and last .cv_loc directive for a given function
   /// id.
   std::map<unsigned, std::pair<size_t, size_t>> MCCVLineStartStop;
 
   /// A collection of MCCVLineEntry for each section.
   std::vector<MCCVLineEntry> MCCVLines;
 
   /// All known functions and inlined call sites, indexed by function id.
   std::vector<MCCVFunctionInfo> Functions;
 };
 
 } // end namespace llvm
 #endif

llvm/include/llvm/MC/MCStreamer.h

public:
   virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
                                      unsigned Column, unsigned Flags,
                                      unsigned Isa, unsigned Discriminator,
                                      StringRef FileName);
 
   /// \brief Associate a filename with a specified logical file number.  This
   /// implements the '.cv_file 4 "foo.c"' assembler directive. Returns true on
   /// success.
-  virtual bool EmitCVFileDirective(unsigned FileNo, StringRef Filename);
+  virtual bool EmitCVFileDirective(unsigned FileNo, StringRef Filename, StringRef Checksum, uint8_t ChecksumKind);
 
   /// \brief Introduces a function id for use with .cv_loc.
   virtual bool EmitCVFuncIdDirective(unsigned FunctionId);
 
   /// \brief Introduces an inline call site id for use with .cv_loc. Includes
   /// extra information for inline line table generation.
   virtual bool EmitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc,
                                            unsigned IAFile, unsigned IALine,
virtual void EmitCVDefRangeDirective(
       StringRef FixedSizePortion);
 
   /// \brief This implements the CodeView '.cv_stringtable' assembler directive.
   virtual void EmitCVStringTableDirective() {}
 
   /// \brief This implements the CodeView '.cv_filechecksums' assembler directive.
   virtual void EmitCVFileChecksumsDirective() {}
 
   /// Emit the absolute difference between two symbols.
   ///
   /// \pre Offset of \c Hi is greater than the offset \c Lo.
   virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
                                       unsigned Size);
 
   virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
   virtual void EmitCFISections(bool EH, bool Debug);
   void EmitCFIStartProc(bool IsSimple);

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

 }
 
 unsigned CodeViewDebug::maybeRecordFile(const DIFile *F) {
   unsigned NextId = FileIdMap.size() + 1;
   auto Insertion = FileIdMap.insert(std::make_pair(F, NextId));
   if (Insertion.second) {
     // We have to compute the full filepath and emit a .cv_file directive.
     StringRef FullPath = getFullFilepath(F);
-    bool Success = OS.EmitCVFileDirective(NextId, FullPath);
+    StringRef Checksum = F->getChecksum();
+    uint8_t ChecksumKind = static_cast<uint8_t>(F->getChecksumKind());
+    bool Success = OS.EmitCVFileDirective(NextId, FullPath, Checksum, ChecksumKind);
     (void)Success;
     assert(Success && ".cv_file directive failed");
   }
   return Insertion.first->second;
 }
 
 CodeViewDebug::InlineSite &
 CodeViewDebug::getInlineSite(const DILocation *InlinedAt,

 
 void CodeViewDebug::emitInlineeLinesSubsection() {
   if (InlinedSubprograms.empty())
     return;
 
   OS.AddComment("Inlinee lines subsection");
   MCSymbol *InlineEnd = beginCVSubsection(DebugSubsectionKind::InlineeLines);
 
   // We don't provide any extra file info.
   // FIXME: Find out if debuggers use this info.
   OS.AddComment("Inlinee lines signature");
   OS.EmitIntValue(unsigned(InlineeLinesSignature::Normal), 4);
 
   for (const DISubprogram *SP : InlinedSubprograms) {
     assert(TypeIndices.count({SP, nullptr}));
     TypeIndex InlineeIdx = TypeIndices[{SP, nullptr}];
 
     OS.AddBlankLine();
     unsigned FileId = maybeRecordFile(SP->getFile());
     OS.AddComment("Inlined function " + SP->getName() + " starts at " +
                   SP->getFilename() + Twine(':') + Twine(SP->getLine()));
     OS.AddBlankLine();
     // The filechecksum table uses 8 byte entries for now, and file ids start at
     // 1.
     unsigned FileOffset = (FileId - 1) * 8;
     OS.AddComment("Type index of inlined function");
     OS.EmitIntValue(InlineeIdx.getIndex(), 4);
     OS.AddComment("Offset into filechecksum table");
     OS.EmitIntValue(FileOffset, 4);
     OS.AddComment("Starting line number");
     OS.EmitIntValue(SP->getLine(), 4);
   }
 
   endCVSubsection(InlineEnd);
 }

llvm/lib/MC/MCAsmStreamer.cpp

unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                   StringRef Filename,
                                   unsigned CUID = 0) override;
   void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
                              unsigned Column, unsigned Flags,
                              unsigned Isa, unsigned Discriminator,
                              StringRef FileName) override;
   MCSymbol *getDwarfLineTableSymbol(unsigned CUID) override;
 
-  bool EmitCVFileDirective(unsigned FileNo, StringRef Filename) override;
+  bool EmitCVFileDirective(unsigned FileNo, StringRef Filename, StringRef Checksum, uint8_t ChecksumKind) override;
   bool EmitCVFuncIdDirective(unsigned FuncId) override;
   bool EmitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc,
                                    unsigned IAFile, unsigned IALine,
                                    unsigned IACol, SMLoc Loc) override;
   void EmitCVLocDirective(unsigned FunctionId, unsigned FileNo, unsigned Line,
                           unsigned Column, bool PrologueEnd, bool IsStmt,
                           StringRef FileName, SMLoc Loc) override;
   void EmitCVLinetableDirective(unsigned FunctionId, const MCSymbol *FnStart,

 }
 
 MCSymbol *MCAsmStreamer::getDwarfLineTableSymbol(unsigned CUID) {
   // Always use the zeroth line table, since asm syntax only supports one line
   // table for now.
   return MCStreamer::getDwarfLineTableSymbol(0);
 }
 
-bool MCAsmStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename) {
-  if (!getContext().getCVContext().addFile(FileNo, Filename))
+bool MCAsmStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename, StringRef Checksum, uint8_t ChecksumKind) {
+  if (!getContext().getCVContext().addFile(FileNo, Filename, Checksum, ChecksumKind))
     return false;
 
   OS << "\t.cv_file\t" << FileNo << ' ';
 
   PrintQuotedString(Filename, OS);
+  PrintQuotedString(Checksum, OS);
+
+  OS << ChecksumKind;
+
   EmitEOL();
   return true;
 }
 
 bool MCAsmStreamer::EmitCVFuncIdDirective(unsigned FuncId) {
   OS << "\t.cv_func_id " << FuncId << '\n';
   return MCStreamer::EmitCVFuncIdDirective(FuncId);
 }

llvm/lib/MC/MCCodeView.cpp

 /// for it.
 bool CodeViewContext::isValidFileNumber(unsigned FileNumber) const {
   unsigned Idx = FileNumber - 1;
   if (Idx < Filenames.size())
     return !Filenames[Idx].empty();
   return false;
 }
 
-bool CodeViewContext::addFile(unsigned FileNumber, StringRef Filename) {
+bool CodeViewContext::addFile(unsigned FileNumber, StringRef Filename, StringRef Checksum, uint8_t ChecksumKind) {
   assert(FileNumber > 0);
   Filename = addToStringTable(Filename);
   unsigned Idx = FileNumber - 1;
   if (Idx >= Filenames.size())
     Filenames.resize(Idx + 1);
 
   if (Filename.empty())
     Filename = "<stdin>";
 
   if (!Filenames[Idx].empty())
     return false;
 
   // FIXME: We should store the string table offset of the filename, rather than
   // the filename itself for efficiency.
   Filename = addToStringTable(Filename);
 
   Filenames[Idx] = Filename;
+
+  Checksums.insert(std::make_pair(Filename, std::make_pair(Checksum,ChecksumKind)));
+
   return true;
 }
 
 bool CodeViewContext::recordFunctionId(unsigned FuncId) {
   if (FuncId >= Functions.size())
     Functions.resize(FuncId + 1);
 
   // Return false if this function info was already allocated.

 
 StringRef CodeViewContext::addToStringTable(StringRef S) {
   SmallVectorImpl<char> &Contents = getStringTableFragment()->getContents();
   auto Insertion =
       StringTable.insert(std::make_pair(S, unsigned(Contents.size())));
   // Return the string from the table, since it is stable.
   S = Insertion.first->first();
   if (Insertion.second) {
     // The string map key is always null terminated.
     Contents.append(S.begin(), S.end() + 1);
   }
   return S;
 }
 
 unsigned CodeViewContext::getStringTableOffset(StringRef S) {
   // A string table offset of zero is always the empty string.
   if (S.empty())
     return 0;
   auto I = StringTable.find(S);
   assert(I != StringTable.end());
   return I->second;
 }
 
 void CodeViewContext::emitStringTable(MCObjectStreamer &OS) {
   MCContext &Ctx = OS.getContext();
   MCSymbol *StringBegin = Ctx.createTempSymbol("strtab_begin", false),
            *StringEnd = Ctx.createTempSymbol("strtab_end", false);
 
   OS.EmitIntValue(unsigned(DebugSubsectionKind::StringTable), 4);
   OS.emitAbsoluteSymbolDiff(StringEnd, StringBegin, 4);
   OS.EmitLabel(StringBegin);
 
   // Put the string table data fragment here, if we haven't already put it
   // somewhere else. If somebody wants two string tables in their .s file, one
   // will just be empty.
   if (!InsertedStrTabFragment) {
     OS.insert(getStringTableFragment());
     InsertedStrTabFragment = true;
   }
 
   OS.EmitValueToAlignment(4, 0);
 
   OS.EmitLabel(StringEnd);
 }
 
 void CodeViewContext::emitFileChecksums(MCObjectStreamer &OS) {
   // Do nothing if there are no file checksums. Microsoft's linker rejects empty
   // CodeView substreams.
   if (Filenames.empty())
     return;
 
   MCContext &Ctx = OS.getContext();
   MCSymbol *FileBegin = Ctx.createTempSymbol("filechecksums_begin", false),
            *FileEnd = Ctx.createTempSymbol("filechecksums_end", false);
 
   OS.EmitIntValue(unsigned(DebugSubsectionKind::FileChecksums), 4);
   OS.emitAbsoluteSymbolDiff(FileEnd, FileBegin, 4);
   OS.EmitLabel(FileBegin);
 
   // Emit an array of FileChecksum entries. We index into this table using the
   // user-provided file number. Each entry is currently 8 bytes, as we don't
   // emit checksums.
   for (StringRef Filename : Filenames) {
     OS.EmitIntValue(getStringTableOffset(Filename), 4);
-    // Zero the next two fields and align back to 4 bytes. This indicates that
-    // no checksum is present.
+
+    std::pair<StringRef, uint8_t> Checksum = Checksums[Filename];
+    if (!Checksum.second) {
+      // There is no checksum.
       OS.EmitIntValue(0, 4);
+      return;
+    }
+    OS.EmitIntValue(static_cast<uint8_t>(Checksum.first.size()), 1);
+    OS.EmitIntValue(Checksum.second, 1);
+    OS.EmitBytes(Checksum.first);
+    OS.EmitValueToAlignment(4);
   }
 
   OS.EmitLabel(FileEnd);
 }
 
 void CodeViewContext::emitLineTableForFunction(MCObjectStreamer &OS,
                                                unsigned FuncId,
                                                const MCSymbol *FuncBegin,
                                                const MCSymbol *FuncEnd) {
   MCContext &Ctx = OS.getContext();
   MCSymbol *LineBegin = Ctx.createTempSymbol("linetable_begin", false),
            *LineEnd = Ctx.createTempSymbol("linetable_end", false);
 
   OS.EmitIntValue(unsigned(DebugSubsectionKind::Lines), 4);
   OS.emitAbsoluteSymbolDiff(LineEnd, LineBegin, 4);
   OS.EmitLabel(LineBegin);
   OS.EmitCOFFSecRel32(FuncBegin, /*Offset=*/0);
   OS.EmitCOFFSectionIndex(FuncBegin);
 
   // Actual line info.
   std::vector<MCCVLineEntry> Locs = getFunctionLineEntries(FuncId);
   bool HaveColumns = any_of(Locs, [](const MCCVLineEntry &LineEntry) {
     return LineEntry.getColumn() != 0;
   });
   OS.EmitIntValue(HaveColumns ? int(LF_HaveColumns) : 0, 2);
   OS.emitAbsoluteSymbolDiff(FuncEnd, FuncBegin, 4);
 
   for (auto I = Locs.begin(), E = Locs.end(); I != E;) {
     // Emit a file segment for the run of locations that share a file id.
     unsigned CurFileNum = I->getFileNum();
     auto FileSegEnd =
         std::find_if(I, E, [CurFileNum](const MCCVLineEntry &Loc) {
           return Loc.getFileNum() != CurFileNum;
         });
     unsigned EntryCount = FileSegEnd - I;
     OS.AddComment("Segment for file '" + Twine(Filenames[CurFileNum - 1]) +
                   "' begins");
     OS.EmitIntValue(8 * (CurFileNum - 1), 4);
     OS.EmitIntValue(EntryCount, 4);
     uint32_t SegmentSize = 12;
     SegmentSize += 8 * EntryCount;
     if (HaveColumns)
       SegmentSize += 4 * EntryCount;
     OS.EmitIntValue(SegmentSize, 4);
 
     for (auto J = I; J != FileSegEnd; ++J) {
       OS.emitAbsoluteSymbolDiff(J->getLabel(), FuncBegin, 4);
       unsigned LineData = J->getLine();
       if (J->isStmt())
         LineData |= LineInfo::StatementFlag;
       OS.EmitIntValue(LineData, 4);
void CodeViewContext::encodeInlineLineTable(MCAsmLayout &Layout,
   const MCSymbol *LastLabel = Frag.getFnStartSym();
   MCCVFunctionInfo::LineInfo LastSourceLoc, CurSourceLoc;
   LastSourceLoc.File = Frag.StartFileId;
   LastSourceLoc.Line = Frag.StartLineNum;
 
   SmallVectorImpl<char> &Buffer = Frag.getContents();
   Buffer.clear(); // Clear old contents if we went through relaxation.
   for (const MCCVLineEntry &Loc : Locs) {
     // Exit early if our line table would produce an oversized InlineSiteSym
     // record. Account for the ChangeCodeLength annotation emitted after the
     // loop ends.
     constexpr uint32_t InlineSiteSize = 12;
     constexpr uint32_t AnnotationSize = 8;
     size_t MaxBufferSize = MaxRecordLength - InlineSiteSize - AnnotationSize;
     if (Buffer.size() >= MaxBufferSize)
       break;
 
for (const MCCVLineEntry &Loc : Locs) {
     // info, so we can skip updates for those.
     if (HaveOpenRange && CurSourceLoc.File == LastSourceLoc.File &&
         CurSourceLoc.Line == LastSourceLoc.Line)
       continue;
 
     HaveOpenRange = true;
 
     if (CurSourceLoc.File != LastSourceLoc.File) {
       // File ids are 1 based, and each file checksum table entry is 8 bytes
       // long. See emitFileChecksums above.
       unsigned FileOffset = 8 * (CurSourceLoc.File - 1);
       compressAnnotation(BinaryAnnotationsOpCode::ChangeFile, Buffer);
       compressAnnotation(FileOffset, Buffer);
     }
 
     int LineDelta = CurSourceLoc.Line - LastSourceLoc.Line;
     unsigned EncodedLineDelta = encodeSignedNumber(LineDelta);
     unsigned CodeDelta = computeLabelDiff(Layout, LastLabel, Loc.getLabel());
     if (CodeDelta == 0 && LineDelta != 0) {

llvm/lib/MC/MCParser/AsmParser.cpp

 
 /// parseDirectiveStabs
 /// ::= .stabs string, number, number, number
 bool AsmParser::parseDirectiveStabs() {
   return TokError("unsupported directive '.stabs'");
 }
 
 /// parseDirectiveCVFile
 /// ::= .cv_file number filename
 bool AsmParser::parseDirectiveCVFile() {
   SMLoc FileNumberLoc = getTok().getLoc();
   int64_t FileNumber;
   std::string Filename;
+  std::string Checksum;
+  int64_t ChecksumKind;
 
   if (parseIntToken(FileNumber,
                     "expected file number in '.cv_file' directive") ||
       check(FileNumber < 1, FileNumberLoc, "file number less than one") ||
       check(getTok().isNot(AsmToken::String),
             "unexpected token in '.cv_file' directive") ||
       // Usually directory and filename are together, otherwise just
       // directory. Allow the strings to have escaped octal character sequence.
       parseEscapedString(Filename) ||
+      check(getTok().isNot(AsmToken::String),
+            "unexpected token in '.cv_file' directive") ||
+      parseEscapedString(Checksum) ||
+      parseIntToken(ChecksumKind, "expected checksum kind in '.cv_file' directive") ||
       parseToken(AsmToken::EndOfStatement,
                  "unexpected token in '.cv_file' directive"))
     return true;
 
-  if (!getStreamer().EmitCVFileDirective(FileNumber, Filename))
+  if (!getStreamer().EmitCVFileDirective(FileNumber, Filename, Checksum, static_cast<uint8_t>(ChecksumKind)))
     return Error(FileNumberLoc, "file number already allocated");
 
   return false;
 }
 
 bool AsmParser::parseCVFunctionId(int64_t &FunctionId,
                                   StringRef DirectiveName) {
   SMLoc Loc;

llvm/lib/MC/MCStreamer.cpp

 }
 
 void MCStreamer::EnsureValidDwarfFrame() {
   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
   if (!CurFrame || CurFrame->End)
     report_fatal_error("No open frame");
 }
 
-bool MCStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename) {
-  return getContext().getCVContext().addFile(FileNo, Filename);
+bool MCStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename, StringRef Checksum, uint8_t ChecksumKind) {
+  return getContext().getCVContext().addFile(FileNo, Filename, Checksum, ChecksumKind);
 }
 
 bool MCStreamer::EmitCVFuncIdDirective(unsigned FunctionId) {
   return getContext().getCVContext().recordFunctionId(FunctionId);
 }
 
 bool MCStreamer::EmitCVInlineSiteIdDirective(unsigned FunctionId,
                                              unsigned IAFunc, unsigned IAFile,