Block 1 and 2 of an MSF file are bit vectors that represent the
list of blocks allocated and free in the file. We had been using
these blocks to write stream data and other data, so we mark them
as the free page map now. We don't yet serialize these pages to
the disk, but at least we make a note of what it is, and avoid
writing random data to them.
Doing this also necessitated cleaning up some of the tests to be
more general and hardcode fewer values, which is nice.
llvm-svn: 275629
Previously we would read a PDB, then write some of it back out,
but write the directory, super block, and other pertinent metadata
back out unchanged. This generates incorrect PDBs since the amount
of data written was not always the same as the amount of data read.
This patch changes things to use the newly introduced `MsfBuilder`
class to write out a correct and accurate set of Msf metadata for
the data *actually* written, which opens up the door for adding and
removing type records, symbol records, and other types of data to
an existing PDB.
llvm-svn: 275627
Zachary Turner