The reverts part of my previous patch. Removing the operators is too much of a
performance penalty to take. The difference is that the Strideable operators are
not transparent.
I still need to remove the UnsafeRawPointer operators, so -Onone performance
will be bad in some cases until this is fixed:
<rdar://problem/27513184> [perf] Strideable operators are not transparent. This is a huge -Onone performance penalty.
As proposed by SE-0107: UnsafeRawPointer:
https://github.com/apple/swift-evolution/blob/master/proposals/0107-unsaferawpointer.md#cstring-conversion
Adds String.init(cString: UnsafePointer<UInt8>)
Adds String.nulTerminatedUTF8CString: ContiguousArray<CChar>
This is necessary for eliminating UnsafePointer conversion. Such
conversion is extremely common for interoperability between Swift
strings and C strings to bridge the difference between CChar and
UTF8.CodeUnit. The standard library does not provide any convenient
utilities for converting between the differently typed
buffers. These APIs will handle the simplest cases involving C
interoperability. More convenience can be added later.
Generic versions of these functions are provided by Strideable.
This is required for SE-0107: UnsafeRawPointer. Otherwise, the presence
of non-generic operator overloads will conflict with existing operators
on String.
* [stdlib] Correct documentation for joined (join -> joined)
* [stdlib] Correct example in documentation for Unmanaged.toOpaque
Fixes <https://bugs.swift.org/browse/SR-1911>.
Relax some preconditions in the cast machinery and write a comprehensive
test suite.
FIXMEs in test/1_stdlib/HashedCollectionCasts.swift.gyb show where the
typechecker doesn't seem to quite work, or the frontend might be
generating the wrong runtime calls.
TODO: Add tests for failing downcasts
Mostly NFC, this is just plumbing for the next patch.
Note that isNever() returns true for any uninhabited
enum.
It should be generalized so that stuff like (Never, Int)
is also known to be uninhabited, or even to support
generic substitutions that yield uninhabited types,
but for now I really see no reason to go that far, and
the current check for an enum with no cases seems
perfectly adequate.
* Add UnsafeRawPointer type and API.
As proposed in SE-0107: UnsafeRawPointer.
https://github.com/apple/swift-evolution/blob/master/proposals/0107-unsaferawpointer.md
The fundamental difference between Unsafe[Mutable]RawPointer and
Unsafe[Mutable]Pointer<Pointee> is simply that the former is used for "untyped"
memory access, and the later is used for "typed" memory access. Let's refer to
these as "raw pointers" and "typed pointers". Because operations on raw pointers
access untyped memory, the compiler cannot make assumptions about the underlying
type of memory and must be conservative. With operations on typed pointers, the
compiler may make strict assumptions about the type of the underlying memory,
which allows more aggressive optimization.
Memory can only be accessed by a typed pointer when it is currently
bound to the Pointee type. Memory can be bound to type `T` via:
- `UnsafePointer<T>.allocate(capacity: n)`
- `UnsafePointer<Pointee>.withMemoryRebound(to: T.self, capacity: n) {...}`
- `UnsafeMutableRawPointer.initializeMemory(as: T.self, at: i, count: n, to: x)`
- `UnsafeMutableRawPointer.initializeMemory(as: T.self, from: p, count: n)`
- `UnsafeMutableRawPointer.moveInitializeMemory(as: T.self, from: p, count: n)`
- `UnsafeMutableRawPointer.bindMemory(to: T.self, capacity: n)`
Mangle UnsafeRawPointer as predefined substitution 'Sv' for Swift void
pointer ([urp] are taken).
* UnsafeRawPointer minor improvements.
Incorporate Dmitri's feedback.
Properly use a _memmove helper.
Add load/storeBytes alignment precondition checks.
Reword comments.
Demangler tests.
* Fix name mangling test cases.
* Fix bind_memory specialization.
Relax some preconditions in the cast machinery and write a comprehensive
test suite.
FIXMEs in test/1_stdlib/HashedCollectionCasts.swift.gyb show where the
typechecker doesn't seem to quite work, or the frontend might be
generating the wrong runtime calls.
TODO: Add tests for failing downcasts
We were using a precondition which crashes the program when invalid input is
provided. We want to provide a way to gracefully check and handle invalid input
or shutdown the program if necessary.
SR-1930
In various cases where we had global operators for non-generic
concrete types (such as String + String), move those operators into
the type. This should not affect the sources, but makes the exposition
of the library cleaner.
Plus, it's a good test for the compiler, which uncovered a few issues
where the compiler was coupled with the library.
- Any is made into a keyword which is always resolved into a TypeExpr,
allowing the removal of the type system code to find TheAnyType before
an unconstrained lookup.
- Types called `Any` can be declared, they are looked up as any other
identifier is
- Renaming/redefining behaviour of source loc methods on
ProtocolCompositionTypeRepr. Added a createEmptyComposition static
method too.
- Code highlighting treats Any as a type
- simplifyTypeExpr also does not rely on source to get operator name.
- Any is now handled properly in canParseType() which was causing
generic param lists containing ‘Any’ to fail
- The import objc id as Any work has been relying on getting a decl for
the Any type. I fix up the clang importer to use Context.TheAnyType
(instead of getAnyDecl()->getDeclaredType()). When importing the id
typedef, we create a typealias to Any and declare it unavaliable.
