Hoist alloc_stack instructions of 'generic' or resilient type to the entry
block. At the same time also perform a very simple stack coloring analysis.
This does not use a true liveness-analysis yet but rather employs some simple
conservative checks to see whether the live ranges of two alloc_stacks might
interfere.
AllocStackHoisting is an IRGen SIL pass. This allows for using IRGen's type
lowering information. Furthermore, hoisting and merging the alloc_stack
instructions this late does not interfere with SIL optimizations because the
resulting SIL never gets serialized.
I apologize in advance to @jrose-apple, who is not a fan
of this fix ;-)
In unoptimized builds, the convenience initializers on
DispatchQueue allocate and immediately deallocate an
instance of OS_dispatch_queue prior to calling the
C function that returns the "real" instance.
This is because we don't have a way to write user-defined
factory initializers yet; convenience initializers still
have an 'initializing' entry point that takes an existing
instance, which we have no choice but to throw away.
Unfortunately, when we perform the fake allocation, we
look up class metadata by calling the wrong Swift runtime
function, causing a crash when we send +allocWithZone:.
Fix this so that the metadata is accessed via a lookup
from the Objective-C runtime, instead of making a totally
fake 'foreign metadata' object -- it looks like there was
code for this already, it just wasn't used in all cases.
While getting metadata for a runtime-only class should be
rare, this feels like a real bug fix, to me.
Second, we would ultimately free the fake object by sending
-release, however OS_dispatch_queue has an override of
-dealloc which doesn't like to be called with a completely
uninitialized instance.
Here, I'm going to drop all pretense of sanity. The patch
just changes IRGen to lower the dealloc_partial_ref instruction
as a call to the object_dispose() Objective-C runtime function
when the class in question is a runtime-only class. This
frees the object without running -dealloc, which *happens*
to work for OS_dispatch_queue.
Fixes <rdar://problem/27226313>.
This flips the switch to have @noescape be the default semantics for
function types in argument positions, for everything except property
setters. Property setters are naturally escaping, so they keep their
escaping-by-default behavior.
Adds contentual printing, and updates the test cases.
There is some further (non-source-breaking) work to be done for
SE-0103:
- We need the withoutActuallyEscaping function
- Improve diagnostics and QoI to at least @noescape's standards
- Deprecate / drop @noescape, right now we allow it
- Update internal code completion printing to be contextual
- Add more tests to explore tricky corner cases
- Small regressions in fixits in attr/attr_availability.swift
Previously, we were using backtrace_symbol and then parsing/modifying its
output. By just using dladdr directly, we have a cleaner and more robust
solution.
rdar://25064742
