Switch most general endpoint to be `flags, parameters, parameterFlags, result`,
instead of opaque `void **`, more specialized ones to use follow argument scheme:
`flags, param0, [flags0], ..., paramN, [flagsN], result` and store parameter/flags
information separately in `FunctionCacheEntry::{Key, Data}` as well.
Currently only single 'inout' flag has been encoded into function
metadata, these changes extend function metadata to support up to
32 flags per parameter.
This is a small code size win, and also gives us some abstraction so that future cooperative ObjC compilers/runtimes might be able to interoperate ObjC class objects with Swift type metadata efficiently than they currently are in the fragile Swift runtime.
While I'm here, I also noticed that swift_getObjCClassMetadata was unnecessarily getting exposed in non-ObjC-interop runtime builds, so I fixed that as well.
This is different from swift_deallocObject in that it applies to objects
at +1 while swift_deallocObject actually only applies to objects whose
state is deiniting (swift_release was called).
It is a runtime function defined in swift. This currently did not have
ABI implications because the ABI happened to be compatible but ...
SR-6235
rdar://problem/35222489
So far single payload enums were implemented in terms of runtime functions which
internally emitted several calls to value witnesses.
This commit adds value witnesses to get and store the enum tag side stepping the
need for witness calls as this information is statically available in many cases
/// int (*getEnumTagSinglePayload)(const T* enum, UINT_TYPE emptyCases)
/// Given an instance of valid single payload enum with a payload of this
/// witness table's type (e.g Optional<ThisType>) , get the tag of the enum.
/// void (*storeEnumTagSinglePayload)(T* enum, INT_TYPE whichCase,
/// UINT_TYPE emptyCases)
/// Given uninitialized memory for an instance of a single payload enum with a
/// payload of this witness table's type (e.g Optional<ThisType>), store the
/// tag.
A simple 'for element in array' loop in generic code operating on a
ContigousArray of Int is ~25% faster on arm64.
rdar://31408033
Move bits mask from Metadata.h to SwiftShims's HeapObject.h. This
exposes the bit masks to the stdlib, so that the stdlib doesn't have
to have its own magic numbers per-platform. This also enhances
readability for BridgeObject, whose magic numbers are mostly derived
from Swift's ABI.
The NTD now references the metadata accessor function for the type, which is a better interface for most things one would want to do with type metadata from a nominal type. The only remaining use in the runtime self really has no requirement to do so. For now, don't disturb the binary layout to prevent breaking downstream clients.
Alter the value metadata layout to use an absolute pointer for the
nominal type descriptor rather than a relative offset relative to the
complete type metadata. Although this is slightly less efficient in
terms of load times, this is more portable across different
environments. For example, PE/COFF does not provide a cross-section
relative offset relocation. Other platform ports are unable to provide
a 64-bit relative offset encoding.
Given that the value witness table reference in the value metadata is
currently an absolute pointer, this page is most likely going to be
dirtied by the loader.
We no longer need this for anything, so remove it from metadata
altogether. This simplifies logic for emitting type metadata and
makes type metadata smaller.
We still pass the parent metadata pointer to type constructors;
removing that is a separate change.
Once generic type metadata includes arguments from all outer contexts,
we need to know how many arguments there are at each nesting depth in
order to properly reconstruct the type name from metadata.
On architectures where the calling convention uses the same argument register as
return register this allows the argument register to be live through the calls.
We use LLVM's 'returned' attribute on the parameter to facilitate this.
We used to perform this optimization via an optimization pass. This was ripped
out some time ago around commit 955e4ed652.
By using LLVM's 'returned' attribute on swift_*retain, we get the same
optimization from the LLVM backend.
This is a blanket pass replacing use of `__LP64__` with
`__POINTER_WIDTH__ == 64`. The latter is more expressive and also LLP64
clean. This change is needed to enable support for Windows x86_64 which
is a LLP64 environment.
- Always include an array of requirement descriptors in the protocol
descriptor. For now, this doesn't contain anything except a general
requirement kind and an optional default implementation, but eventually
this can be augmented with type / name metadata. This array is always
emitted as constant.
- Guarantee the value of the extent fields in a protocol descriptor and
slightly tweak their meaning.
- Move the private-data field out of line in a generic witness table
descriptor so that the main descriptor can be emitted as constant.
- Rely on IRGen's notion of the witness-table layout instead of assuming
that SILWitnessTable and SILDefaultWitnessTable match the actual
physical layout.
This version of the patch uses a hack in which we assign internal rather
than private linkage to certain symbols in order to work around a Darwin
linker bug.
Previous patches changed the runtime to copy the vtable from the
superclass rather than IRGen emitting it statically for generic
and resilient classes.
However for generic classes we would still copy the vtable entries
for methods defined in the immediate class from the template.
Instead, store them in the nominal type descriptor, where they use
less space since we can use relative pointers, and copy them out of
there.
This will allow us to 'slim down' generic class templates eventually.
Both swift_init{Struct,Class}Metadata_UniversalStrategy() wish to
avoid instantiating type metadata for field types if possible.
The struct version took an array of the more general TypeLayout objects,
whereas the class version was implemented earlier and took an array
of size/alignment pairs.
Since we can emit static TypeLayouts for all fixed-size types,
the class version can use the more general TypeLayout type also.
On 32bit platforms there are 7 bits reserved for the unowned retain count. This
makes overflow a likely scenario. Implement overflow into the side table.
rdar://33495003
