Somehow all the functionality to write PDB files got removed,
probably accidentally when uploading the patch perhaps the wrong
one got uploaded. This re-adds all the code, as well as the
corresponding test.
llvm-svn: 274248
This adds method and tests for writing to a PDB stream. With
this, even a PDB stream which is discontiguous can be treated
as a sequential stream of bytes for the purposes of writing.
Reviewed By: ruiu
Differential Revision: http://reviews.llvm.org/D21157
llvm-svn: 272369
This converts remaining uses of ByteStream, which was still
left in the symbol stream and type stream, to using the new
StreamInterface zero-copy classes.
RecordIterator is finally deleted, so this is the only way left
now. Additionally, more error checking is added when iterating
the various streams.
With this, the transition to zero copy pdb access is complete.
llvm-svn: 271101
PDBs can be extremely large. We're already mapping the entire
PDB into the process's address space, but to make matters worse
the blocks of the PDB are not arranged contiguously. So, when
we have something like an array or a string embedded into the
stream, we have to make a copy. Since it's convenient to use
traditional data structures to iterate and manipulate these
records, we need the memory to be contiguous.
As a result of this, we were using roughly twice as much memory
as the file size of the PDB, because every stream was copied
out and re-stitched together contiguously.
This patch addresses this by improving the MappedBlockStream
to allocate from a BumpPtrAllocator only when a read requires
a discontiguous read. Furthermore, it introduces some data
structures backed by a stream which can iterate over both
fixed and variable length records of a PDB. Since everything
is backed by a stream and not a buffer, we can read almost
everything from the PDB with zero copies.
Differential Revision: http://reviews.llvm.org/D20654
Reviewed By: ruiu
llvm-svn: 270951
We have need to reuse this functionality, including making
additional generic stream types that are smarter about how and
when they copy memory versus referencing the original memory.
So all of these structures belong in the common library
rather than being pdb specific.
llvm-svn: 270751
Zachary Turner