Cursor info requires access to the underlying AST, which is not
thread-safe. This manifest as crashes when performing concurrent
cursor-info requests on the same generated interface. We already
prevented concurrent cursor-infos on regular Swift files by using the
ASTManager, but generated interfaces use the InterfaceGenContext which
may use either an ASTUnit or its own internal CompilerInstance.
rdar://problem/27311624
(Headers first)
It has been generally agreed that we need to do this reorg, and now
seems like the perfect time. Some major pass reorganization is in the
works.
This does not have to be the final word on the matter. The consensus
among those working on the code is that it's much better than what we
had and a better starting point for future bike shedding.
Note that the previous organization was designed to allow separate
analysis and optimization libraries. It turns out this is an
artificial distinction and not an important goal.
The code goes into its own sub-tree under 'tools' but tests go under 'test',
so that running 'check-swift' will also run all the SourceKit tests.
SourceKit is disabled on non-darwin platforms.
