This is a staging attribute that will eventually mean "fixed-contents"
for structs and "closed" for enums, as described in
docs/LibraryEvolution.rst.
This is pretty much the minimal set of types that must be fixed-layout,
because SILGen makes assumptions about their lowering.
If desired, some SILGen refactoring can allow some of these to be
resilient. For example, bridging value types could be made to work
with resilient types.
Currently they do nothing but allow stdlib code to use regular (Bool)
types. However, soon the wrappers for the _native variants will
provide point-of-use sanity checking.
These need to be fully generic to support class protocols and
single-payload enums (not just for optional). It also avoids a massive
amount of overloading for all the reference type variations
(AnyObject, Native, Unknown, Bridge) x 2 for optional versions of
each.
Because the wrapper is generic, type checking had to be deferred until
IRGen. Generating code for the wrapper itself will result in an
IRGen-time type error. They need to be transparent anyway for proper
diagnostics, but also must be internal.
Note that the similar external API type checks ok because it
forces conformance to AnyObject.
The sanity checks are disabled because our current facilities for
unsafe type casting are incomplete and unsound. SILCombine can
remove UnsafeMutablePointer and RawPointer casts by assuming layout
compatibility. IRGen will later discover layout incompatibility and
generate a trap.
I'll send out a proposal for improving the casting situation so we can
get the sanity checks back.
Swift SVN r28057
This reverts commit 64e9f11211a19fa603f5bc2d2bea171a9b07d3fa.
I think this is breaking ExistentialCollection test in the
Release + stdlib asserts build.
Swift SVN r27947
The wrappers for the _native variants provide point-of-use sanity checking.
They also allows stdlib code to use regular (Bool) types.
These need to be fully generic to support class protocols. It also
avoids a massive amount of overloading for all the reference type
variations (AnyObject, Native, Unknown, Bridge) x 2 for optional
versions of each.
Because the wrapper is generic, type checking had to be deferred until
IRGen. Generating code for the wrapper itself will result in an
IRGen-time type error. They need to be transparent anyway for proper
diagnostics, but also must be internal.
The external API passes type checks because it forces conformance to AnyObject.
Swift SVN r27930
Fixes <rdar://problem/18151694> Add Builtin.checkUnique to avoid lost Array copies
The isUniquelyReference APIs are now correct in the presence of full
inlining and ARC optimization. The ARC optimizer can't see into the
Builtin, which lowers to a special SIL instruction.
Swift SVN r27929
Changes compared to the original version:
I fixed the 2 bugs and added a test for the so far undetected missing range check bug.
To keep the SIL simple (4 basic blocks for arr[x]) I extracted the slow path for getElement into a
non-inlinable function.
On the other hand I inlined _typeCheck into the slow-path function.
This speeds up NSArray accesses because now only a single objectAtIndex is required for both
type checking and element retrieving.
Update on performance: DeltaBlue is now only 12% better (and not 25%). I suspect this is because
now Arnold's tail duplication cannot detect the ObjC call in the slow path.
Swift SVN r26935
Now that we can check isNative and NoDTC (no deffered type check needed) with a single bit-mask operation,
it makes sense to have a single array property call for it.
I replaced the the semantics call array.props.needsElementTypeCheck with array.props.isNativeNoDTC,
which is the combination of isNative && !needsElementTypeCheck. I kept array.props.isNative, which is not used for now,
but might be useful in the future, e.g. for array operations which don't care about type checks.
The optimized SIL for a class array access arr[i] now contains the minimum of 4 basic blocks.
PerfTests show +25% for DeltaBlue and some improvemements for -Onone.
Swift SVN r26871
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
