Fixes a general category (pun intended) of scalar-alignment bugs
surrounding exchanging non-scalar-aligned indices between views and
for slicing.
SE-0180 unifies the Index type of String and all its views and allows
non-scalar-aligned indices to be used across views. In order to
guarantee behavior, we often have to check and perform scalar
alignment. To speed up these checks, we allocate a bit denoting
known-to-be-aligned, so that the alignment check can skip the
load. The below shows what views need to check for alignment before
they can operate, and whether the indices they produce are aligned.
┌───────────────╥────────────────────┬──────────────────────────┐
│ View ║ Requires Alignment │ Produces Aligned Indices │
╞═══════════════╬════════════════════╪══════════════════════════╡
│ Native UTF8 ║ no │ no │
├───────────────╫────────────────────┼──────────────────────────┤
│ Native UTF16 ║ yes │ no │
╞═══════════════╬════════════════════╪══════════════════════════╡
│ Foreign UTF8 ║ yes │ no │
├───────────────╫────────────────────┼──────────────────────────┤
│ Foreign UTF16 ║ no │ no │
╞═══════════════╬════════════════════╪══════════════════════════╡
│ UnicodeScalar ║ yes │ yes │
├───────────────╫────────────────────┼──────────────────────────┤
│ Character ║ yes │ yes │
└───────────────╨────────────────────┴──────────────────────────┘
The "requires alignment" applies to any operation taking a
String.Index that's not defined entirely in terms of other operations
taking a String.Index. These include:
* index(after:)
* index(before:)
* subscript
* distance(from:to:) (since `to` is compared against directly)
* UTF16View._nativeGetOffset(for:)
* Update Decimal.swift
Fix `Decimal.magnitude` so that `Decimal.nan.magnitude` is no longer incorrectly `0`.
Port changes from apple/swift-corelibs-foundation#1759, crucially correcting an error where `(0 as Decimal).doubleValue` returned `.nan`.
* [gardening] Zap indentation error
* Add test for `Decimal.nan.magnitude`
* Apply reviewer suggestion
Clean up `doubleValue`
* Provide a default implementation of multipliedFullWidth
Previously, [U]Int64 fatalErrored on 32b platforms, which is obviously undesirable. This PR provides a default implementation on FixedWidthInteger, which is not ideally efficient for all types, but is correct, and gives the optimizer all the information that it needs to generate good code in the important case of Int64 arithmetic on 32b platforms. There's still some minor room for improvement, but we'll call that an optimizer bug now.
* Clarify comments somewhat, remove `merge` nested function
I was only using `merge` in one place, so making it a function seems unnecessary. Also got rid of some trucatingIfNeeded inits where the compiler is able to reason that no checks are needed anyway.
* Add some basic test coverage specifically for multipliedFullWidth
* Fix typo, further clarify bounds comments.
* Make new defaulted implementation @_aEIC so we don't need availability.
1) Enable tests that use `import Dispatch` on Linux. Add substitution
`%import-libdispatch` that needs to be used for all cross-platform
tests (i.e., tests that are intended to be run on other platforms
than Darwin) that do `import Dispatch` or enable thread sanitizer.
2) Make sure as many existing Dispatch and TSan tests as possible run on
Linux. Mark tests that would require substantial work with
`UNSUPPORTED: OS=linux-gnu`.
3) Add integration-style Swift test that shows that TSan finds a simple
race when using `Dispatch.async` incorrectly. A more complete test
suite for TSan's libdispatch support lives on the LLVM/compiler-rt
side.
rdar://problem/49177535
For odd roots of negative values, we need to take the root of the *magnitude* of the number to avoid a NaN from the platform's implementation of `pow`, then restore the sign afterwards. We had the basic logic in place already, but were missing the step of taking the magnitude first. Also modified a test case to find this error.
The embedded shell script in the RUN command for lit is problematic for
non-sh shell environments (i.e. Windows). This adjusts the tests to
uniformly build the code for the ObjC runtime. However, the Objective-C
code is only built under the same circumstances that it is currently
enabled - the availability of the needed frameworks. The empty object
on other runtimes will have no material impact. The swift side of it
checks whether the runtime is built with ObjC interop. This allows us
to largely use the same command line for all the targets. The last
missing piece is that the `-fobjc-runtime` requires that we run a modern
ObjC runtime. We enable this unconditionally in lit for the non-Apple
targets.
This improves the validation test coverage for the standard library on
Windows.
* [Foundation] Fix availability of NSValue.value(of:)
(cherry picked from commit fbe5563d60)
* [Foundation] NSValue.value(of:): Reinstate runtime OS version check
Introduce a fix to detect and diagnose situations when omitted
generic arguments couldn't be deduced by the solver based on
the enclosing context.
Example:
```swift
struct S<T> {
}
_ = S() // There is not enough context to deduce `T`
```
Resolves: rdar://problem/51203824
Some of the tests in KVOKeyPaths.swift check problems that were not fixed
until Swift 5.1 so they are not expected to pass when running with the
5.0 libraries.
rdar://problem/50173830
