[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
diff --git a/llvm/tools/llvm-pdbdump/LLVMOutputStyle.h b/llvm/tools/llvm-pdbdump/LLVMOutputStyle.h
index 9443025..f5740ec 100644
--- a/llvm/tools/llvm-pdbdump/LLVMOutputStyle.h
+++ b/llvm/tools/llvm-pdbdump/LLVMOutputStyle.h
@@ -25,6 +25,8 @@
   Error dump() override;
 
 private:
+  void discoverStreamPurposes();
+
   Error dumpFileHeaders();
   Error dumpStreamSummary();
   Error dumpFreePageMap();
@@ -47,6 +49,7 @@
   PDBFile &File;
   ScopedPrinter P;
   codeview::CVTypeDumper Dumper;
+  std::vector<std::string> StreamPurposes;
 };
 }
 }