These always fail, and it doesn't make sense to inline this check into the cast site, so provide additional runtime functions for metatype-to-objc-existential casts.
Swift SVN r23237
When there's no init function, we can do relaxed loads and stores, because the metadata record will not change in the course of canonicalization. However, if there is initialization, we need to do a release-consume in order to ensure the initialization is visible to readers.
Swift SVN r23119
Per review from Dmitri and Greg. We can do relaxed loads (if we miss the store, we'll lock the global hashtable and find the metadata that way), but we need a seq_cst barrier when we store.
Swift SVN r23101
The race here was benign--we just end up writing the same uniqued value twice to the invasive cache. Relax the assertion that this used to trip.
Swift SVN r23098
Move the uniquing information for ForeignTypeMetadata behind the address point so we can share the layout between foreign classes and the existing layout for struct and enum metadata. Emit metadata records for imported structs and enums as foreign metadata candidates, and dynamically unique references to the metadata by calling swift_getForeignTypeMetadata.
Swift SVN r23081
As a stopgap till IRGen properly emits indirected class references, support direct class reference protocol conformance records. This should get us to the point we can replace the dlsym hack with the new implementation.
Swift SVN r23073
We were missing -_tryRetain, -_isDeallocating, -allowsWeakReference and -retainWeakReference implementations on SwiftObject, so forming an ObjC weak reference to a pure Swift object always failed and produced a nil reference. Fixes rdar://problem/18637774.
This can be reapplied now that we properly call objc_destructInstance on deallocation.
Swift SVN r23070
We can share a lookup cache entry under the generic metadata pattern when the witness table for a protocol conformance is shared among all instances of the type. (This happens to always be the case currently.)
Swift SVN r23062
Set up the basic logic for first looking into a cache then pulling in conformances from enqueued images and trying again for exact-matchable types (pretty much just nongeneric native value types).
Swift SVN r23053
Set up lazy registration of a dyld add image callback that looks up the "__DATA,__swift1_proto" section in the loaded image. As a first-pass sanity check, just walk the section and dump the records.
Swift SVN r23025
Per Joe, a low level retained-pointer-with-user-controlled-spare-bits
type would still be useful for space efficiency even on platforms that
don't need ObjC interop.
Swift SVN r22943
When we emit a witness table, build a protocol conformance record for it, and emit the list of all conformance records into a "__swift1_proto" section of the data segment.
Swift SVN r22939
We want to use the reserved space in the metadata pattern for protocol conformance caching, and this link lets us find the metadata pattern from an instance of the generic type.
Swift SVN r22898
Generated code on x86_64 for swift_retain and swift_release and
swift_allocObject are unchanged. arm64 is improved by using weaker
memory barriers, fixing rdar://17423624.
Swift SVN r22887
This is a type that has ownership of a reference while allowing access to the
spare bits inside the pointer, but which can also safely hold an ObjC tagged pointer
reference (with no spare bits of course). It additionally blesses one
Foundation-coordinated bit with the meaning of "has swift refcounting" in order
to get a faster short-circuit to native refcounting. It supports the following
builtin operations:
- Builtin.castToBridgeObject<T>(ref: T, bits: Builtin.Word) ->
Builtin.BridgeObject
Creates a BridgeObject that contains the bitwise-OR of the bit patterns of
"ref" and "bits". It is the user's responsibility to ensure "bits" doesn't
interfere with the reference identity of the resulting value. In other words,
it is undefined behavior unless:
castReferenceFromBridgeObject(castToBridgeObject(ref, bits)) === ref
This means "bits" must be zero if "ref" is a tagged pointer. If "ref" is a real
object pointer, "bits" must not have any non-spare bits set (unless they're
already set in the pointer value). The native discriminator bit may only be set
if the object is Swift-refcounted.
- Builtin.castReferenceFromBridgeObject<T>(bo: Builtin.BridgeObject) -> T
Extracts the reference from a BridgeObject.
- Builtin.castBitPatternFromBridgeObject(bo: Builtin.BridgeObject) -> Builtin.Word
Presents the bit pattern of a BridgeObject as a Word.
BridgeObject's bits are set up as follows on the various platforms:
i386, armv7:
No ObjC tagged pointers
Swift native refcounting flag bit: 0x0000_0001
Other available spare bits: 0x0000_0002
x86_64:
Reserved for ObjC tagged pointers: 0x8000_0000_0000_0001
Swift native refcounting flag bit: 0x0000_0000_0000_0002
Other available spare bits: 0x7F00_0000_0000_0004
arm64:
Reserved for ObjC tagged pointers: 0x8000_0000_0000_0000
Swift native refcounting flag bit: 0x4000_0000_0000_0000
Other available spare bits: 0x3F00_0000_0000_0007
TODO: BridgeObject doesn't present any extra inhabitants. It ought to at least provide null as an extra inhabitant for Optional.
Swift SVN r22880
We were missing -_tryRetain, -_isDeallocating, -allowsWeakReference and -retainWeakReference implementations on SwiftObject, so forming an ObjC weak reference to a pure Swift object always failed and produced a nil reference. Fixes rdar://problem/18637774.
Swift SVN r22710
layouts. Introduce new SIL instructions to initialize
and open existential metatype values.
Don't actually, y'know, lift any of the restriction on
existential metatypes; just pointlessly burn extra
memory storing them.
Swift SVN r22592
Rename the existing misleadingly-named "isClassType" to "isClassObject", and document that it refers to (swift or ObjC) class objects, the latter of which aren't always type metadata.
Swift SVN r22153
Somehow this got out of sync, and IRGen's idea of which flag it was collided with "hasExtraInhabitants", causing hilarity to ensue whenever weak or protocol types were packed in optionals. Fixes rdar://problem/17814752.
Swift SVN r21803
instances of Swift subclasses of ObjC classes.
We were already doing this in the runtime. This patch
unhides the runtime's mask word (swift_isaMask) and makes
IR-gen take advantage of it when it can.
Swift SVN r21592
pass the size and alignment of each field. Take advantage
of this to pass a constant size and alignment when
possible.
This avoids the need to recursively find type metadata for
every field type, allowing generic recursively-structured
classes to be built. There are a number of more complicated
cases that this approach isn't good enough for, but this
is good enough for now to fix rdar://18067671.
Also make an effort to properly support generic subclasses
of Objective-C classes.
Swift SVN r21506
Strings that get used to name SpriteKit nodes on Mavericks end up weakly referenced by NSMapTables using the legacy GC-compatible weak pointer personality, which for our bridged objects ended up falling into the default NSObject implementation of reference counting via the "_tryRetain" SPI, causing heap corruption. I tried really hard to isolate a test case and failed, but this fixes the Adventure crasher in <rdar://problem/17887502>.
Swift SVN r20966
The allocator's crimes include:
* It uses OS SPI that must not be used by non-OS apps.
* It does not play well with memory debugging tools like Instruments.
* It does not return memory to the OS in response to memory pressure.
* It is less tested than we would like because many configurations
inadvertently turn it off (such as running from Xcode).
* Its per-thread magazine implementation does not actually work.
* Its "try alloc" flag is incompletely implemented and never used.
* Its "zero fill" flag is unimplemented and inconsistently used.
Swift SVN r20757
