for extra inhabitants.
For structs in particular, this eliminates a major source
of abstraction penatlies. For example, an optional struct
containing an object pointer is now represented the same
way as an optional object pointer, which is critical for
correctly importing CF types as Unmanaged<T>!.
In time, we should generalize this to consider all elements
as sources for extra inhabitants, as well as exploiting
spare bits in the representation, but getting the
single-element case right really provides the bulk of the
benefit.
This commit restores r17242 and r17243 with a fix to use
value witnesses that actually forward the right type metadata
down. We were already generating these value witnesses in
the dependent struct VWT pattern, but I was being too clever
and trying to use the underlying value witness directly.
Swift SVN r17267
This reverts commit r17243. We can't just forward the extra inhabitant payloads
from a field, because they will end up receiving metadata for the incorrect
type and crashing.
Swift SVN r17251
extra inhabitants.
Obviously this should eventually be generalized to
take from any element, but this is good enough to
give us zero-cost abstraction via single-field structs.
Contains some bugfixes for the tuple-extra-inhabitant
changes as well, because test coverage for optional
structs is obviously quite a bit richer than for
optional tuples.
All of this is leading towards unblocking IRGen for
importing CFStringRef as Unmanaged<CFString>!.
Swift SVN r17243
Set a bit for types that are non-bitwise-takable, and calculate it as part of runtime struct and enum layout. Include 'bitwise takable' as part of the runtime 'is inline' calculation to be consistent with the compile-time policy change in r17008.
Swift SVN r17036
Until we lock down the Swift ABI and ship with the OS, we need to be resilient
in the face of ObjC dynamic subclassing and OS changes. In practice, this means
that we need to have a swift runtime ABI to read the isa out of objects. I've
added it as of r. See: swift_getClassMetadata()
We can and will optimize swift_getClassMetadata into a single instruction once
we lockdown our ABI and ship with the OS.
See also: <rdar://problem/16735599>
Swift SVN r16889
I've put these fields on the class object for now, just
so we can at least theoretically update them. A superclass
that grew left rather than right could maybe even be made
to work with this schema, but probably not.
rdar://16705821
Swift SVN r16880
We really don't need to support individual objects
this large, much less more than 4 billion fields in
a single type.
Also rearrange the fields to bring the instance
size/alignment fields closer to the class header,
just for a minor locality win.
Swift SVN r16879
Add value witnesses for destroyArray, initializeArrayWithCopy, and initializeArrayWithTake{FrontToBack,BackToFront}, and fill out the runtime value witness table implementations. Stub out the IRGen ones for now.
Swift SVN r16772
the value buffer comes first.
The motivation for doing this is similar to the
motivation for moving it for class existentials:
it eliminates the need for an offset for the most
common accesses, which is particularly important
for the generic value witnesses.
Also try to hard-code that layout in fewer places,
or at least static_assert the places that have to
do so.
Swift SVN r16279
pointer first.
This most important effect of this is that accesses to that
field don't need to be dynamically offsetted past an arbitrary
number of value witnesses, which is pretty nice for the
generic value witnesses.
Swift SVN r16243
Language features like erasing concrete metatype
values are also left for the future. Still, baby steps.
The singleton ordinary metatype for existential types
is still potentially useful; we allow it to be written
as P.Protocol.
I've been somewhat cavalier in making code accept
AnyMetatypeType instead of a more specific type, and
it's likely that a number of these places can and
should be more restrictive.
When T is an existential type, parse T.Type as an
ExistentialMetatypeType instead of a MetatypeType.
An existential metatype is the formal type
\exists t:P . (t.Type)
whereas the ordinary metatype is the formal type
(\exists t:P . t).Type
which is singleton. Our inability to express that
difference was leading to an ever-increasing cascade
of hacks where information is shadily passed behind
the scenes in order to make various operations with
static members of protocols work correctly.
This patch takes the first step towards fixing that
by splitting out existential metatypes and giving
them a pointer representation. Eventually, we will
need them to be able to carry protocol witness tables
Swift SVN r15716
There's still a lot of manual intervention required, but
at least we don't have the constants written in two different
places.
Should be NFC.
Swift SVN r15242
Building the field type vector is potentially expensive and the vector isn't needed unless we do reflectiony things to a type, so let's use a lazy accessor. Make room for it, but don't populate it yet, so we can deal with fallout from the metadata layout change.
Swift SVN r15194
For ObjC classes, use class_copyIvarList to walk the ivars, and produce the summary string using -debugDescription. Still to come:
- visiting the base class as a child, and
- calling -debugQuickLookObject to get the quicklook object. Still waiting on a final design for the IDERepresentation API.
Swift SVN r14626
This is more in line with all other modules currently on our system.
If/when we get our final name for the language, we're at least now set
up to rename the library without /too/ much trouble. (This is mostly just
a lot of searching for "import swift", "swift.", "'swift'", and '"swift"'.
The compiler itself is pretty much just using STDLIB_NAME consistently now,
per r13758.)
<rdar://problem/15972383>
Swift SVN r14001
Mock up a naive Printable protocol, and do some dirty tricks in the runtime to implement a 'printAny' function that uses swift_conformsToProtocol to look up a conformance to Printable if the type has one, or falls back to a dumb opaque printing if it doesn't. Use this to make Array<T> Printable in some way or another for all T.
Swift SVN r13902
Given our constraints for 1.0, we can actually sort-of look up protocol conformances just by dlsym'ing the symbol for their protocol witness table, since we won't be implementing runtime witness table instantiation or private conformances anytime soon. To make this work for generic types, distastefully regress our mangling for protocol conformances by assuming all generic conformances are completely general to the unbound generic type and leave the generic parameters out of the mangling.
Swift SVN r13901
This lets IRGen avoid emitting an alloca for common generic metadata instantiations. These entry points can also be marked "readnone", and the general getGenericMetadata entry point can be "readonly", giving LLVM's optimizer a fighting chance on unspecialized generic code.
Swift SVN r12789
Start using null-page values as extra inhabitants when laying out single-payload enums that contain class pointers as their payload type. Don't use inhabitants that set the lowest bit, to avoid trampling potential ObjC tagged pointer representations. This means that 'T?' for class type T now has a null pointer representation. Enums with multiple empty cases, as well as nested enums like 'T??', should now have optimal representations for class type T as well.
Note that we don't yet expose extra inhabitants for aggregates that contain heap object references, such as structs with class fields, Swift function types, or class-bounded existentials (even when the existential has no witness tables).
Swift SVN r10061
I tried hard find all references to 'func' in documentation, comments and
diagnostics, but I am sure that I missed a few. If you find something, please
let me know.
rdar://15346654
Swift SVN r9886
When we need a reference to protocol or protocol composition type metadata, ask for it through the runtime, instead of referencing statically-emitted protocol metadata.
Swift SVN r9871
Same deal as for opaque existentials--pre-instantiate a static witness table for one-witness-table types (the zero-witness-tables case is nicely handled by Builtin.ObjCPointer's value witness), and generate a vwtable using dynamic witness implementations for each different-sized container on demand as necessary.
Swift SVN r9850
The assign-with-copy operation on existentials is complex enough to be emitted as a function call, which is currently generated on-demand by IRGen for every existential layout. We can instead use the implementation out of the runtime. Provide entry points for zero, one, and any number of witness tables.
Swift SVN r9815
Set up a metadata cache for existential type metadata. Instantiate existential metadata by first sorting the protocol list, so that it is order invariant, precomputing the overall witness table count and class constraint of the composition so it can be cached in the existential metadata.
We still need to implement value witnesses for existential containers in the runtime before this is complete. We can at least test the uniquing and flags computations at this point.
Swift SVN r9727
We'll emit protocol descriptors with ObjC-compatible layout. Existential type metadata will be instantiated by the runtime and reference these descriptors to describe the type.
Swift SVN r9708
No reason to try to shove the kind-dependent bits after the tail-emplaced generic parameter description. Let's plan to put the field names in here too so we can give a reasonable lowest common denominator display for aggregates even without debug info.
Swift SVN r9490
In the short term LLDB needs to be able to find and parse generic parameter vectors and field offset vectors from metadata records without necessarily having the debug info necessary to do so. Start off the descriptor by including these offsets and lengths.
Swift SVN r9458
