Not only it does not achieve what the comment says (_storage has the
type _ContiguousArrayStorageBase), but optimizations that would break
semantics of this code would be invalid anyway.
Swift SVN r29056
includes a number of QoI things to help people write the correct code. I will commit
the testcase for it as the next patch.
The bulk of this patch is moving the stdlib, testsuite and validation testsuite to
the new syntax. I moved a few uses of "as" patterns back to as? expressions in the
stdlib as well.
Swift SVN r27959
ContiguousArrayBuffer is used as the buffer for Array when ObjC interop is disabled, so even though there's no behavior difference from "_isValidSubscript(_:hoistedIsNativeBuffer:)" for a ContiguousArrayBuffer, we want the interface to be interchangeable with the one for the bridgeable ArrayBuffer.
Swift SVN r27409
Now we initialize the array buffer from sequences using unsafe pointer
arithmetic, which avoids extra retain/release traffic. But since the
size of the sequence is not known in advance, we only initialize as much
as underestimateCount() promises, and fall back to the slow approach for
the tail. Nevertheless, for collections, where the size is known
precisely, this technique is suboptimal only by one branch.
rdar://20530390
Swift SVN r27380
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
