to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
This is intended to replace the current YAML format for general use.
It's ~10x more compact than YAML, and ~40% more compact than gzipped YAML:
llvmidx.riff = 20M, llvmidx.yaml = 272M, llvmidx.yaml.gz = 32M
It's also simpler/faster to read and write.
The format is a RIFF container (chunks of (type, size, data)) with:
- a compressed string table
- simple binary encoding of symbols (with varints for compactness)
It can be extended to include occurrences, Dex posting lists, etc.
There's no rich backwards-compatibility scheme, but a version number is included
so we can detect incompatible files and do ad-hoc back-compat.
Alternatives considered:
- compressed YAML or JSON: bulky and slow to load
- llvm bitstream: confusing model and libraries are hard to use. My attempt
produced slightly larger files, and the code was longer and slower.
- protobuf or similar: would be really nice (esp for back-compat) but the
dependency is a big hassle
- ad-hoc binary format without a container: it seems clear we're going
to add posting lists and occurrences here, and that they will benefit
from sharing a string table. The container makes it easy to debug
these pieces in isolation, and make them optional.
Reviewers: ioeric
Subscribers: mgorny, ilya-biryukov, MaskRay, jkorous, mgrang, arphaman, kadircet, cfe-commits
Differential Revision: https://reviews.llvm.org/D51585
llvm-svn: 341375
Chandler Carruth