<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>One more:</div><div><br></div><div>3. In the purpose of mapping source file index to string, I found this code: <br></div><div><br></div><div>Expected<codeview::DebugChecksumsSubsectionRef><br>ModuleDebugStreamRef::findChecksumsSubsection() const {<br> codeview::DebugChecksumsSubsectionRef Result;<br> for (const auto &SS : subsections()) {<br> if (SS.kind() != DebugSubsectionKind::FileChecksums)<br> continue;<br><br> if (auto EC = Result.initialize(SS.getRecordData()))<br> return std::move(EC);<br> return Result;<br> }<br> return Result;<br>}<br></div><div><br></div><div>Subsections() is populated here:</div><div><br></div><div> if (auto EC = Reader.readSubstream(C13LinesSubstream, C13Size))<br> return EC;<br><br> BinaryStreamReader SymbolReader(SymbolsSubstream.StreamData);<br> if (auto EC =<br> SymbolReader.readArray(SymbolArray, SymbolReader.bytesRemaining()))<br> return EC;<br><br> BinaryStreamReader SubsectionsReader(C13LinesSubstream.StreamData);<br> if (auto EC = SubsectionsReader.readArray(Subsections,<br> SubsectionsReader.bytesRemaining()))<br> return EC;<br><br></div><div>So it looks like there should be one of these just after the C13Lines substream:</div><div><br></div><div>struct DebugSubsectionHeader {<br> support::ulittle32_t Kind; // codeview::DebugSubsectionKind enum<br> support::ulittle32_t Length; // number of bytes occupied by this record.<br>};</div><div><br></div><div>But when I look there with my own code I only see zeroes:</div><div><br></div><div>read C13 line info 142964 bytes<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }<br>DebugSubsectionHeader{ .Kind = DebugSubsectionKind.None, .Length = 0 }</div><div><repeats until end of stream></div><div><br></div><div>Any clues?<br></div><div><br></div></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Aug 31, 2018 at 2:17 AM Andrew Kelley <<a href="mailto:superjoe30@gmail.com">superjoe30@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Zachary,</div><div><br></div><div>Thanks for the help on IRC earlier. I've got code that can capture a stack trace and then discover for each address, its module, function, source index, line, and column.</div><div><br></div><div>I still have a couple of loose ends though. Do you know what's going on here?</div><div><br></div><div>1. There appears to be 8 bytes before every LineFragmentHeader. Here's some of my own debug output, which matches llvm-pdbutil's output. You can see it says "unknown bytes: ...".<br></div><div dir="ltr"><br></div><div dir="ltr">read C13 line info 136720 bytes<br>unknown bytes: f2 00 00 00 60 00 00 00<br>LineFragmentHeader{ .RelocOffset = 0, .RelocSegment = 5, .Flags = LineFlags{ .LF_HaveColumns = true, .unused = 0 }, .CodeSize = 52 }<br>has column: true<br>LineBlockFragmentHeader{ .NameIndex = 0, .NumLines = 6, .BlockSize = 84 }<br>LineNumberEntry{ .Offset = 0, .Flags = 101 } Flags{ .Start = 101, .End = 17, .IsStatement = false }<br></div><div><snip some LineNumberEntry's></div><div>ColumnNumberEntry{ .StartColumn = 5, .EndColumn = 0 }<br>ColumnNumberEntry{ .StartColumn = 30, .EndColumn = 0 }<br>unknown bytes: f2 00 00 00 f0 00 00 00<br>LineFragmentHeader{ .RelocOffset = 64, .RelocSegment = 5, .Flags = LineFlags{ .LF_HaveColumns = true, .unused = 0 }, .CodeSize = 366 }<br>has column: true<br>LineBlockFragmentHeader{ .NameIndex = 8, .NumLines = 18, .BlockSize = 228 }<br>LineNumberEntry{ .Offset = 0, .Flags = 53 } Flags{ .Start = 53, .End = 20, .IsStatement = false }<br>LineNumberEntry{ .Offset = 20, .Flags = 54 } Flags{ .Start = 54, .End = 24, .IsStatement = false }</div><div><etc></div><div><br></div><div>Do you know what's going on with these 8 bytes? I have scoured llvm-pdbutil's source but I cannot find where these bytes are coming from.</div><div><br></div><div>2. Is there a simpler way to find out which is the /names (string table) stream index without porting the entire hash table implementation?<br></div><div><br></div></div></div></div></div>
</blockquote></div>