This has a couple benefits:
- Since metadata allocations are already guarded by a lock, the allocator doesn't require synchronization, and can be much much simpler and a little faster than malloc.
- By bypassing malloc, we also avoid tools like 'heap' prying into our metadata cache and misrepresenting cache entries keyed on classes as live objects, fixing rdar://problem/20562886.
In my unscientific local tests, this appeared to give a small across-the-board improvement to Onone performance in the perf test suite, though not far enough from noise for me to declare that definitively. Fixing the bug is the bigger point here.
Swift SVN r27856
We have enough flag bits on function types now to warrant stashing an extra word in the metadata key alongside the arguments and results, so add one, and pack the number of arguments, function convention, and 'throws' bit in there. This lets us merge the separate metadata caches for thick/thin/block/C functions into one, saving a bit of runtime memory, and simplifying a bunch of repetitive code in the runtime and IRGen.
This also fixes a subtle bug we had where the runtime getFunctionTypeMetadata function expected the result argument to be passed in the arguments array, but IRGen was passing it as a separate argument, which would have caused function type metadata to fail to be uniqued by result type.
Swift SVN r27651
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876
