Explanation: There were some scenarios where we could call an unsafe
function without marking the expression as unsafe. These affect mostly
cases where the function's result is passed to another function or
returned. This PR makes sure we always flag functions with unsafe return
types, even if their result is not stored anywhere for later use.
Issues: rdar://157237301
Original PRs: #83520
Risk: Low, worst case scenario the user has to add redundant unsafe
keywords in strict memory safe mode.
Testing: Added a compiler test.
Reviewers: @DougGregor
In anticipation of potential future HW features, e.g. armv8.5 memory
tagging, only use the high 4 bytes as discriminator bits in
_BridgeObject rather than the top 8 bits. Utilize two perf flags to
cover this instead. This requires shifting around a fair amount of
internal complexity.
Refactor and rename _StringGutsSlice, apply NFC-aware fast paths to a
new buffered iterator.
Also, fix bug in _typeName which used to assume ASCIIness and better
SIL optimizations on StringObject.
This is a giant squashing of a lot of individual changes prototyping a
switch of String in Swift 5 to be natively encoded as UTF-8. It
includes what's necessary for a functional prototype, dropping some
history, but still leaves plenty of history available for future
commits.
My apologies to anyone trying to do code archeology between this
commit and the one prior. This was the lesser of evils.
Create a _StringRepresentation struct to standardize internal testing
on. Internalize much of _StringGuts, except for some SPI hacks, and
update tests to use _StringRepresentation.
