Commit Graph

7 Commits

Author SHA1 Message Date
Zachary Turner 0d43c1c339 [pdb] Finish conversion to zero copy pdb access.
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
2016-05-28 05:21:57 +00:00
Zachary Turner 1de49c9ffd Resubmit "[pdb] Allow zero-copy read support for symbol streams.""
Due to differences in template instantiation rules, it is not
portable to static_assert(false) inside of an invalid specialization
of a template.  Instead I just =delete the method so that it can't
be used, and leave a comment that it must be explicitly specialized.

llvm-svn: 271027
2016-05-27 18:47:20 +00:00
Chad Rosier 6c247c8cc8 Revert "[pdb] Allow zero-copy read support for symbol streams."
This reverts commit r271024 due to error: static_assert failed
"You must either provide a specialization of VarStreamArrayExtractor
or a custom extractor"

llvm-svn: 271026
2016-05-27 18:31:02 +00:00
Zachary Turner 3a9a23ae62 [pdb] Allow zero-copy read support for symbol streams.
This reduces the amount of memory used by llvm-pdbdump by roughly
1/3 of the size of the PDB file.

Differential Revision: http://reviews.llvm.org/D20724
Reviewed By: ruiu

llvm-svn: 271025
2016-05-27 18:20:20 +00:00
Zachary Turner 8dbe3629a0 [codeview,pdb] Try really hard to conserve memory when reading.
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
2016-05-27 01:54:44 +00:00
Zachary Turner 2f09b5091c Put PDB parsing code into a pdb namespace.
llvm-svn: 268072
2016-04-29 17:28:47 +00:00
Zachary Turner 1822af542f Parse module information from DBI stream.
This gets more data out of the DBI strema of the PDB.  In
particular it extracts the metadata for the list of modules
(compilands) that this PDB contains info about, and adds support
for dumping these fields to llvm-pdbdump.

Differential Revision: http://reviews.llvm.org/D19570
Reviewed By: ruiu

llvm-svn: 267818
2016-04-27 23:41:42 +00:00