pdbdump: print out the name of the stream 0.

[ruiu]

Summary

pdbdump: print out the name of the stream 0.

llvm/trunk/include/llvm/DebugInfo/PDB/Raw/RawConstants.h

enum PdbRaw_TpiVer : uint32_t {
   PdbTpiV40 = 19950410,
   PdbTpiV41 = 19951122,
   PdbTpiV50 = 19961031,
   PdbTpiV70 = 19990903,
   PdbTpiV80 = 20040203,
 };
 
 enum SpecialStream : uint32_t {
+  // Stream 0 contains the copy of previous version of the MSF directory.
+  // We are not currently using it, but technically if we find the main
+  // MSF is corrupted, we could fallback to it.
+  OldMSFDirectory = 0,
+
   StreamPDB = 1,
   StreamTPI = 2,
   StreamDBI = 3,
   StreamIPI = 4,
 };
 
 enum class DbgHeaderType : uint16_t {
   FPO,

llvm/trunk/test/DebugInfo/PDB/pdbdump-headers.test

 ; EMPTY-NEXT:   Unknown1: 0
 ; EMPTY-NEXT:   BlockMapAddr: 24
 ; EMPTY-NEXT:   NumDirectoryBlocks: 1
 ; EMPTY-NEXT:   BlockMapOffset: 98304
 ; EMPTY-NEXT:   DirectoryBlocks: [23]
 ; EMPTY-NEXT:   NumStreams: 17
 ; EMPTY-NEXT: }
 ; EMPTY-NEXT: Streams [
-; EMPTY-NEXT:   Stream 0: [???] (40 bytes)
+; EMPTY-NEXT:   Stream 0: [Old MSF Directory] (40 bytes)
 ; EMPTY-NEXT:   Stream 1: [PDB Stream] (118 bytes)
 ; EMPTY-NEXT:   Stream 2: [TPI Stream] (5392 bytes)
 ; EMPTY-NEXT:   Stream 3: [DBI Stream] (739 bytes)
 ; EMPTY-NEXT:   Stream 4: [IPI Stream] (784 bytes)
 ; EMPTY-NEXT:   Stream 5: [Named Stream "/LinkInfo"] (0 bytes)
 ; EMPTY-NEXT:   Stream 6: [Global Symbol Hash] (556 bytes)
 ; EMPTY-NEXT:   Stream 7: [Public Symbol Hash] (604 bytes)
 ; EMPTY-NEXT:   Stream 8: [Public Symbol Records] (104 bytes)

 ; ALL:   Unknown1: 0
 ; ALL:   BlockMapAddr: 24
 ; ALL:   NumDirectoryBlocks: 1
 ; ALL:   BlockMapOffset: 98304
 ; ALL:   DirectoryBlocks: [23]
 ; ALL:   NumStreams: 17
 ; ALL: }
 ; ALL: Streams [
-; ALL:   Stream 0: [???] (40 bytes)
+; ALL:   Stream 0: [Old MSF Directory] (40 bytes)
 ; ALL:   Stream 1: [PDB Stream] (118 bytes)
 ; ALL:   Stream 2: [TPI Stream] (5392 bytes)
 ; ALL:   Stream 3: [DBI Stream] (739 bytes)
 ; ALL:   Stream 4: [IPI Stream] (784 bytes)
 ; ALL:   Stream 5: [Named Stream "/LinkInfo"] (0 bytes)
 ; ALL:   Stream 6: [Global Symbol Hash] (556 bytes)
 ; ALL:   Stream 7: [Public Symbol Hash] (604 bytes)
 ; ALL:   Stream 8: [Public Symbol Records] (104 bytes)

llvm/trunk/tools/llvm-pdbdump/llvm-pdbdump.cpp

static Error dumpStreamSummary(ScopedPrinter &P, PDBFile &File) {
   for (auto &NSE : IS.named_streams()) {
     NamedStreams[NSE.second] = NSE.first();
   }
 
   for (uint16_t StreamIdx = 0; StreamIdx < StreamCount; ++StreamIdx) {
     std::string Label("Stream ");
     Label += to_string(StreamIdx);
     std::string Value;
-    if (StreamIdx == StreamPDB)
+    if (StreamIdx == OldMSFDirectory)
+      Value = "Old MSF Directory";
+    else if (StreamIdx == StreamPDB)
       Value = "PDB Stream";
     else if (StreamIdx == StreamDBI)
       Value = "DBI Stream";
     else if (StreamIdx == StreamTPI)
       Value = "TPI Stream";
     else if (StreamIdx == StreamIPI)
       Value = "IPI Stream";
     else if (StreamIdx == DS.getGlobalSymbolStreamIndex())