[pdb] Print out some more info when dumping a raw stream.

We have various command line options that print the type of a
stream, the size of a stream, etc but nowhere that it can all be
viewed together.

Since a previous patch introduced the ability to dump the bytes
of a stream, this seems like a good place to present a full view
of the stream's properties including its size, what kind of data
it represents, and the blocks it occupies.  So I added the
ability to print that information to the -stream-data command
line option.

llvm-svn: 281077

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
index bbcfbfca810..403c02b4268 100644
--- a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
+++ b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
@@ -200,6 +200,10 @@ uint32_t MappedBlockStream::getLength() const { return StreamLayout.Length; }
 
 bool MappedBlockStream::tryReadContiguously(uint32_t Offset, uint32_t Size,
                                             ArrayRef<uint8_t> &Buffer) const {
+  if (Size == 0) {
+    Buffer = ArrayRef<uint8_t>();
+    return true;
+  }
   // Attempt to fulfill the request with a reference directly into the stream.
   // This can work even if the request crosses a block boundary, provided that
   // all subsequent blocks are contiguous.  For example, a 10k read with a 4k