This is the first step towards round-tripping symbol information,
and thusly being able to write symbol information to a PDB.
This patch writes the symbol information for each compiland to
the Yaml when running in pdb2yaml mode. There's still some loose
ends, such as what to do about relocations (necessary in order to
print linkage names), how to print enums with friendly names, and
how to give the dumper access to the StringTable, but this is a
good first start.
llvm-svn: 283641