The code generation model for a particular declaration or conformance
can be defined explicitly with `@export(interface)`,
`@export(implementation)`, or `@inlinable` (for declarations),
indicating where the definition will occur.
Embedded Swift also has some limitations on what can be emitted into
IR. For example, a generic function cannot be `@export(interface)`
because Embedded Swift does not support unspecialized generics.
Compute the effective code generation model based on what was
explicitly specified, the limitations of the model, and the default
code generation model for the given module, which defaults to
"inlinable" but can be made "implementation" by the DeferredCodeGen
feature. Use the effective code generation model for IR- and SIL-level
determinations of linkage and where to emit symbols.
[WIP] Start computing and using the "effective" code generation model
FIXUP linkage of the alias symbol
This teaches ClangImporter to represent a base class of a C++ foreign reference type as a Swift superclass if the base class is an FRT itself, and is a primary base class. Such base types are stored at offset zero within the derived type, which makes casting trivial.
This makes the following possible:
* casting an instance of derived FRT to base FRT explicitly with `as`
* passing an instance of derived FRT as a function parameter of type base FRT
* calling a method of base FRT on an instance of derived FRT without the compiler having to clone methods
Several constructs are not supported:
* downcasting, i.e. casting an instance of base FRT to derived FRT
* casting arrays/sets/dictionaries of FRTs
* casting to virtual bases
Support for casting to a base FRT that is not the primary base (not at offset zero) can be added in a follow-up change.
rdar://85881664 / resolves https://github.com/swiftlang/swift/issues/80231
@export(interface) makes it so that Embedded Swift will emit a strong
definition of a symbol in its defining module, and use that symbol in
other modules. Extend this notion to non-generic types, where we will
emit a strong definition for the full type metadata, and let it be
referenced from other modules rather than the lazy, shared emission.
Implements rdar://176392354.
rdar://158239258
This change adds logic in the compiler to compute malloc type ids and emit them together with typed allocation calls. It also adds the new runtime function swift_allocObjectTyped, which calls typed malloc.
ObjC ivar metadata has up to now emitted an empty string for the ivar's objc type encoding. Conversely, ObjC property metadata is emitted with an objc type encoding. This changes the compiler to also emit an objc type encoding for ivars.
The motivation for this change is for lldb to print ivars of classes declared in Objective-C but implemented in Swift, as defined in [SE-0436](https://github.com/swiftlang/swift-evolution/blob/main/proposals/0436-objc-implementation.md). Without the presence of type encoding for ivars, lldb is unable to present to the user the ivars/properties of instances of such classes.
rdar://138569299
In C++, a primary base class that is placed in the beginning of the type's memory layout isn't always the type that is the first in the list of bases – the base types might be laid out in memory in a different order.
This makes sure that IRGen handles base types of C++ structs in the correct order.
This fixes an assertion in asserts-enabled compilers, and an out-of-memory error in asserts-disabled compilers. The issue was happening for both value types and foreign reference types. This change also includes a small refactoring to reuse the logic between the two code paths.
rdar://140848603
The generality of the `AvailabilityContext` name made it seem like it
encapsulates more than it does. Really it just augments `VersionRange` with
additional set algebra operations that are useful for availability
computations. The `AvailabilityContext` name should be reserved for something
pulls together more than just a single version.
In most cases this was already checked with `ClassLayout::isFixedLayout`. But for classes which are imported from another module and contain implementation-only C-imported stored properties, those properties don't show up in the class layout. Stack promoting such classes will reserve too less space on the stack which leads to all kind of memory corruption problems. The fix is to also check `ClassLayout::isFixedSize`, which returns false for such classes.
Fixes a miscompile
rdar://131067105
Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
This now specifies a category name that’s used in TBDGen, IRGen, and PrintAsClang. There are also now category name conflict diagnostics; these subsume some @implementation diagnostics.
(It turns out there was already a check for @objc(CustomName) to make sure it wasn’t a selector!)
When an @objc @implementation class requires the use of `ClassMetadataStrategy::Update` because some of its stored properties do not have fixed sizes, we adjust the direct field offsets during class realization by emitting a custom metadata update function which calls a new entry point in the Swift runtime. That entry point adjusts field offsets like `swift_updateClassMetadata2()`, but it only assumes that the class has Objective-C metadata, not Swift metadata.
This commit introduces an alternative mechanism which does the same thing without using any Swift-only metadata. It’s a rough implementation with important limitations:
• We’re currently using the field offset vector, which means that field offsets are being emitted into @objc @implementation classes; these will be removed.
• The new Swift runtime entry point duplicates a lot of `swift_updateClassMetadata2()`’s implementation; it will be refactored into something much smaller and more compact.
• Availability bounds for this feature have not yet been implemented.
Future commits in this PR will correct these issues.
- VTableSpecializer, a new pass that synthesizes a new vtable per each observed concrete type used
- Don't use full type metadata refs in embedded Swift
- Lazily emit specialized class metadata (LazySpecializedClassMetadata) in IRGen
- Don't emit regular class metadata for a class decl if it's generic (only emit the specialized metadata)
- In embedded Swift, classes get a simplified metadata: Basically just a vtable + destructor + superclass pointer.
- Only non-resilient (intended as permanent restriction), non-generic classes (for now) supported.
- Relax the check that prohibits metadata emission and usage to allow classes.
Moving the query implementation up to the AST library from SIL will allow
conveniences to be written on specific AST element classes. For instance, this
will allow `EnumDecl` to expose a convenience that enumerates element decls
that are available during lowering.
Also, improve naming and documentation for these queries.
For `alloc_ref [bare] [stack]` and `global_value [bare]` omit the object header initialization.
The `bare` flag means that the object header is not used.
This was already done with a peephole optimization inside IRGen for `global_value`. But now rely on the SIL `bare` flag.
Reformatting everything now that we have `llvm` namespaces. I've
separated this from the main commit to help manage merge-conflicts and
for making it a bit easier to read the mega-patch.
This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
Egor Zhdan
Doug Gregor
Dario Rexin
Arnold Schwaighofer
Slava Pestov
Hamish Knight
Ellis Hoag
Anthony Latsis
Dave Lee
Nate Chandler
Kuba Mracek
Ben Barham
Allan Shortlidge
swift-ci
Erik Eckstein
Xi Ge
Tim Kientzle
Becca Royal-Gordon
Konrad `ktoso` Malawski
zoecarver
Pavel Yaskevich
Evan Wilde