Summary:
Currently SHA1 is about 10% of our CPU, this patch reduces it to ~1%.
xxhash is a well-defined (stable) non-cryptographic hash optimized for
fast checksums (like crc32).
Collisions shouldn't be a problem, despite the reduced length:
- for actual file content (used to invalidate bg index shards), there
are only two versions that can collide (new shard and old shard).
- for file paths in bg index shard filenames, we would need 2^32 files
with the same filename to expect a collision. Imperfect hashing may
reduce this a bit but it's well beyond what's plausible.
This will invalidate shards on disk (as usual; I bumped the version),
but this time the filenames are changing so the old files will stick
around :-( So this is more expensive than the usual bump, but would be
good to land before the v9 branch when everyone will start using bg index.
Reviewers: kadircet
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64306
llvm-svn: 365311
Add an initial '::' qualifier to all usages of 'testing' namespace that
did not have one.
The goal is to make our code style in tests more consistent.
llvm-svn: 360026
Summary:
Motivation:
- this layout is a pain to work with
- without a common root, it's painful to express things like "disable clangd" (D61122)
- CMake/lit configs are a maintenance hazard, and the more the one-off hacks
for various tools are entangled, the more we see apathy and non-ownership.
This attempts to use the bare-minimum configuration needed (while still
supporting the difficult cases: windows, standalone clang build, dynamic libs).
In particular the lit.cfg.py and lit.site.cfg.py.in are merged into lit.cfg.in.
The logic in these files is now minimal.
(Much of clang-tools-extra's lit configs can probably be cleaned up by reusing
lit.llvm.llvm_config.use_clang(), and every llvm project does its own version of
LDPATH mangling. I haven't attempted to fix any of those).
Docs are still in clang-tools-extra/docs, I don't have any plans to touch those.
Reviewers: gribozavr
Subscribers: mgorny, javed.absar, MaskRay, jkorous, arphaman, kadircet, jfb, cfe-commits, ilya-biryukov, thakis
Tags: #clang
Differential Revision: https://reviews.llvm.org/D61187
llvm-svn: 359424
Sam McCall