[pdb] Print out file names instead of file offsets.

When printing line information and file checksums, we were printing
the file offset field from the struct header.  This teaches
llvm-pdbdump how to turn those numbers into the filename.  In the
case of file checksums, this is done by looking in the global
string table.  In the case of line contributions, this is done
by indexing into the file names buffer of the DBI stream.  Why
they use a different technique I don't know.

llvm-svn: 271630

1 files changed, 18 insertions, 8 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
index 8c46957706e..e79d6572be1 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
@@ -345,7 +345,6 @@ Error DbiStream::initializeFileInfo() {
 
   FixedStreamArray<ulittle16_t> ModIndexArray;
   FixedStreamArray<ulittle16_t> ModFileCountArray;
-  FixedStreamArray<little32_t> FileNameOffsets;
 
   // First is an array of `NumModules` module indices.  This is not used for the
   // same reason that `NumSourceFiles` is not used.  It's an array of uint16's,
@@ -373,10 +372,8 @@ Error DbiStream::initializeFileInfo() {
   if (auto EC = FISR.readArray(FileNameOffsets, NumSourceFiles))
     return EC;
 
-  StreamRef NamesBufferRef;
-  if (auto EC = FISR.readStreamRef(NamesBufferRef))
+  if (auto EC = FISR.readStreamRef(NamesBuffer))
     return EC;
-  StreamReader Names(NamesBufferRef);
 
   // We go through each ModuleInfo, determine the number N of source files for
   // that module, and then get the next N offsets from the Offsets array, using
@@ -387,10 +384,10 @@ Error DbiStream::initializeFileInfo() {
     uint32_t NumFiles = ModFileCountArray[I];
     ModuleInfos[I].SourceFiles.resize(NumFiles);
     for (size_t J = 0; J < NumFiles; ++J, ++NextFileIndex) {
-      uint32_t FileOffset = FileNameOffsets[NextFileIndex];
-      Names.setOffset(FileOffset);
-      if (auto EC = Names.readZeroString(ModuleInfos[I].SourceFiles[J]))
-        return EC;
+      if (auto Name = getFileNameForIndex(NextFileIndex))
+        ModuleInfos[I].SourceFiles[J] = Name.get();
+      else
+        return Name.takeError();
     }
   }
 
@@ -400,3 +397,16 @@ Error DbiStream::initializeFileInfo() {
 uint32_t DbiStream::getDebugStreamIndex(DbgHeaderType Type) const {
   return DbgStreams[static_cast<uint16_t>(Type)];
 }
+
+Expected<StringRef> DbiStream::getFileNameForIndex(uint32_t Index) const {
+  StreamReader Names(NamesBuffer);
+  if (Index >= FileNameOffsets.size())
+    return make_error<RawError>(raw_error_code::index_out_of_bounds);
+
+  uint32_t FileOffset = FileNameOffsets[Index];
+  Names.setOffset(FileOffset);
+  StringRef Name;
+  if (auto EC = Names.readZeroString(Name))
+    return std::move(EC);
+  return Name;
+}