LLVM r355981 changed various intrinsic functions, including expect,
to require immediate arguments. Swift's _branchHint function has an
expected value that is passed in as an argument, so that it cannot
use LLVM's expect intrinsic. The good news is that _branchHint is only
ever used with immediate arguments, so we can just move the intrinsic
into _fastPath and _slowPath and use those instead of _branchHint.
As was noted in the documentation, the _fastPath and _slowPath names are
confusing but we have passed the point where we can simply rename them.
We could add new names but would still need to keep the old ones around
for binary compatibility, and it is not clear that it is worth the
trouble. I have removed that note from the documentation.
Compilation of code sample snippets was broken due to using the same
identifier as the `type` function itself to store its result resulting
in:
```swift
func printGenericInfo<T>(_ value: T) {
let type = type(of: value)
print("'\(value)' of type '\(type)'")
}
// error: repl.swift:2:16: error: variable used within its own initial
// value
// let type = type(of: value)
// ^
```
Result:
- Snippets are more copy&paste friendly.
- Resolves https://bugs.swift.org/browse/SR-9915
This fixes the Windows platform, where the aligned allocation path is
not malloc-compatible. It won't have any observable difference on
Darwin or Linux, aside from manually allocated memory on Linux now
being consistently 16-byte aligned (heap objects will still be 8-byte
aligned on Linux).
It is unfortunate that we can't guarantee Swift-allocated memory via
Unsafe*Pointer is malloc compatible on Windows. It would have been
nice for that to be a cross platform guarantee since it's normal to
allocate in C and deallocate in Swift or vice-versa. Now we have to
tell developers to always use _aligned_malloc/_aligned_free when
transitioning between Swift/C if they expect their code to work on
Windows.
Even though this fix isn't required today on Darwin/Linux, it makes
good sense to guarantee that the allocation/deallocation paths are
consistent.
This is done by specifying a constant that stdlib can use to round up
alignment, _swift_MinAllocationAlignment. The runtime asserts that
this constant is greater than MALLOC_ALIGN_MASK for all platforms.
This way, manually allocated buffers will always use the aligned
allocation path. If users specify an alignment less than m
round up so users don't need
to pass the same alignment to deallocate the buffer). This constant
does not need to be ABI.
Alternatives are:
1. Require users of Unsafe*Pointer to specify the same alignment
during deallocation. This is obviously madness.
2. Introduce new runtime entry points:
swift_alignedAlloc/swift_alignedDealloc, introduce corresponding
new builtins, and have Unsafe*Pointer always call those. This would
make the runtime API a little more obvious but would introduce
complexity in other areas of the compiler and it doesn't have any
other significant benefit. Less than 16-byte alignment of manually
allocated buffers on Linux is a non-goal.
* [stdlib] Minor documentation revisions
* [docs] Convert 'nonoptional' to 'non-optional'
We're switching to 'non-optional' across the board, as the unhyphenated
form is too easy to read as 'no-noptional'.
Previously we had a single mask for all x86-64 targets which included both the top and bottom bits. This accommodated simulators, which use the top bit, while macOS uses the bottom bit, but reserved one bit more than necessary on each. This change breaks out x86-64 simulators from non-simulators and reserves only the one bit used on each.
rdar://problem/34805348 rdar://problem/29765919
The functions in LibcShims are used externally, some directly and some through @inlineable functions. These are changed to SWIFT_RUNTIME_STDLIB_SPI to better match their actual usage. Their names are also changed to add "_swift" to the front to match our naming conventions.
Three functions from SwiftObject.mm are changed to SPI and get a _swift prefix.
A few other support functions are also changed to SPI. They already had a prefix and look like they were meant to be SPI anyway. It was just hard to notice any mixup when they were #defined to the same thing.
rdar://problem/35863717
* Removing FIXME from methods also marked always/never
* Unavailable/deprecated things don't need inlining
* Trivial implementations
* Enum namespaces
* Unsafe performance of opaque/raw pointer
* Dump doesn't need to be fast
* Error paths shouldn't require inlining
* Consistency with surrounding code
* Lazy performance needs specialization
Now that bridging is enabled, unify the ObjC and non-ObjC paths. Expand
the comment with how to efficiently grab the object reference and when
it can be enabled.
Include the initial implementation of _StringGuts, a 2-word
replacement for _LegacyStringCore. 64-bit Darwin supported, 32-bit and
Linux support in subsequent commits.
* Reduce array abstraction on apple platforms dealing with literals
Part of the ongoing quest to reduce swift array literal abstraction
penalties: make the SIL optimizer able to eliminate bridging overhead
when dealing with array literals.
Introduce a new classify_bridge_object SIL instruction to handle the
logic of extracting platform specific bits from a Builtin.BridgeObject
value that indicate whether it contains a ObjC tagged pointer object,
or a normal ObjC object. This allows the SIL optimizer to eliminate
these, which allows constant folding a ton of code. On the example
added to test/SILOptimizer/static_arrays.swift, this results in 4x
less SIL code, and also leads to a lot more commonality between linux
and apple platform codegen when passing an array literal.
This also introduces a couple of SIL combines for patterns that occur
in the array literal passing case.
Move bits mask from Metadata.h to SwiftShims's HeapObject.h. This
exposes the bit masks to the stdlib, so that the stdlib doesn't have
to have its own magic numbers per-platform. This also enhances
readability for BridgeObject, whose magic numbers are mostly derived
from Swift's ABI.
* Unify the capitalization across all user-visible error messages (fatal errors, assertion failures, precondition failures) produced by the runtime, standard library and the compiler.
* Update some more tests to the new expectations.
- Revisions to unsafeDowncast and withVaList
- Fix the Int64/UInt64 discussion
- Buffer pointer revisions
- Fix Optional example to use new integer methods
- Revise and correct some UnsafeRawBufferPointer docs
- Fix symmetricDifference examples
- Fix wording in FloatingPoint.nextDown
- Update ImplicitlyUnwrappedOptional
- Clarify elementsEqual
- Minor integer doc fixes
- Comment for _AppendKeyPath
- Clarification re collection indices
- Revise RangeExpression.relative(to:)
- Codable revisions
Having such a builtin makes it easier for the optimizer to reason about what is actually happening.
I plan to add later some optimizations which can optimize pieces of code dominated by such a check.
