And replace them with explicit `metatype` instruction in the entry block.
This allows such metatype instructions to be deleted if they are dead.
This was already done for performance-annotated functions. But now do this for all functions.
It is essential that performance-annotated functions are specialized in the same way as other functions.
Because otherwise it can happen that the same specialization has different performance characteristics in different modules.
And it's up to the linker to select one of those ODR functions when linking.
Also, dropping metatype arguments is good for performance and code size in general.
This change also contains a few bug fixes for dropping metatype arguments.
rdar://110509780
* [SILOptimizer] Add prespecialization for arbitray reference types
* Fix benchmark Package.swift
* Move SimpleArray to utils
* Fix multiple indirect result case
* Remove leftover code from previous attempt
* Fix test after rebase
* Move code to compute type replacements to SpecializedFunction
* Fix ownership when OSSA is enabled
* Fixes after rebase
* Changes after rebasing
* Add feature flag for layout pre-specialization
* Fix pre_specialize-macos.swift
* Add compiler flag to benchmark build
* Fix benchmark SwiftPM flags
For performance annotations we need the generic specializer to trop non-generic metatype argumentrs
(which we don't do in general). For this we need a separate mangling.
Mangling can fail, usually because the Node structure has been built
incorrectly or because something isn't supported with the old remangler.
We shouldn't just terminate the program when that happens, particularly
if it happens because someone has passed bad data to the demangler.
rdar://79725187
This pattern was really error-prone. I've fixed multiple bugs related
to CurGenericSignature not being set correctly at the right time, and
found another latent bug by inspection while doing this cleanup.
If the specialized function has a re-abstracted (= converted from indirect to direct) resilient argument or return types, use an alternative mangling: "TB" instead of "Tg".
Resilient parameters/returns can be converted from indirect to direct if the specialization is created within the type's resilience domain, i.e. in its module (where the type is loadable).
In this case we need to generate a different mangled name for the specialized function to distinguish it from specializations in other modules, which cannot re-abstract this resilient type.
This fixes a miscompile resulting from ODR-linking specializations from different modules, which in fact have different function signatures.
https://bugs.swift.org/browse/SR-13900
rdar://71914016
This attribute allows to define a pre-specialized entry point of a
generic function in a library.
The following definition provides a pre-specialized entry point for
`genericFunc(_:)` for the parameter type `Int` that clients of the
library can call.
```
@_specialize(exported: true, where T == Int)
public func genericFunc<T>(_ t: T) { ... }
```
Pre-specializations of internal `@inlinable` functions are allowed.
```
@usableFromInline
internal struct GenericThing<T> {
@_specialize(exported: true, where T == Int)
@inlinable
internal func genericMethod(_ t: T) {
}
}
```
There is syntax to pre-specialize a method from a different module.
```
import ModuleDefiningGenericFunc
@_specialize(exported: true, target: genericFunc(_:), where T == Double)
func prespecialize_genericFunc(_ t: T) { fatalError("dont call") }
```
Specially marked extensions allow for pre-specialization of internal
methods accross module boundries (respecting `@inlinable` and
`@usableFromInline`).
```
import ModuleDefiningGenericThing
public struct Something {}
@_specializeExtension
extension GenericThing {
@_specialize(exported: true, target: genericMethod(_:), where T == Something)
func prespecialize_genericMethod(_ t: T) { fatalError("dont call") }
}
```
rdar://64993425
