There are multiple reasons to do this. Primarily this is
useful as an optimization. Whenever analysis can determine that no
potentially conflicting access occurs within the scope, the access can
be demoted to "nontracking". It is also useful as an escape hatch for
future code deploying to older runtimes. For example, if a future access
scope may cross threads, and the older runtime doesn't know how to
migrate threads.
See <rdar://problem/37507434> add a flag to swift_beginAccess to inform
the runtime that an access might migrate between threads
32-bit iOS 9 simulator and 32-bit watchOS 2 simulator do not support
C++ thread_local, even though clang's has_feature(cxx_thread_local)
thinks they do.
rdar://35063043
This is a smorgasbord of warning cleanups in the runtime. This just
adjusts the casts for the various types. There were a number of casts
which lost const qualifiers on the type.
* Extend Swift runtime issue reporting for @objc inference to include details about the declaration of the method (that is missing the @objc annotation) and a suggested fix-it. This changes the ABI of RuntimeErrorDetails, so we're also bumping the version.
* Update SwiftObject.mm
* Implements a debugger hook (breakpoint) API and data structure. This structure is passed to the debugger and describes extra information about a fatal error or a non-fatal warning, which should be logged as a runtime issue.
This debugger hook is then used from two places, which currently only log to stderr:
- Runtime exclusivity violations.
- Swift 3 implicit Obj-C entrypoints.
A subsequent LLDB support will be able to catch these callbacks and show the runtime issues in a better way than just logging them to stderr. When the debugger is not attached, this shouldn't have any effect.
