This parses the TPI stream (stream 2) from the PDB file. This stream
contains some header information followed by a series of codeview records.
There is some additional complexity here in that alongside this stream of
codeview records is a serialized hash table in order to efficiently query
the types. We parse the necessary bookkeeping information to allow us to
reconstruct the hash table, but we do not actually construct it yet as
there are still a few things that need to be understood first.
Differential Revision: http://reviews.llvm.org/D19840
Reviewed By: ruiu, rnk
llvm-svn: 268343
PDB has a lot of similar data structures. We already have code
for parsing a Name Map, but PDB seems to have a different but
very similar structure that is a hash table. This is the
beginning of code needed in order to parse the name hash table,
but it is not yet complete. It parses the basic metadata of
the hash table, the bucket array, and the names buffer, but
doesn't use any of these fields yet as the data structure
requires a non-trivial amount of work to understand.
llvm-svn: 268268
The motivation for this change is that PDB has the notion of
streams and substreams. Substreams often consist of variable
length structures that are convenient to be able to treat as
guaranteed, contiguous byte arrays, whereas the streams they
are contained in are not necessarily so, as a single stream
could be spread across many discontiguous blocks.
So, when processing data from a substream, we want to be able
to assume that we have a contiguous byte array so that we can
cast pointers to variable length arrays and such.
This leads to the question of how to be able to read the same
data structure from either a stream or a substream using the
same interface, which is where this patch comes in.
We separate out the stream's read state from the underlying
representation, and introduce a `StreamReader` class. Then
we change the name of `PDBStream` to `MappedBlockStream`, and
introduce a second kind of stream called a `ByteStream` which is
simply a sequence of contiguous bytes. Finally, we update all
of the std::vectors in `PDBDbiStream` to use `ByteStream` instead
as a proof of concept.
llvm-svn: 268071
