Most of the work of this patch is just propagating metadata states
throughout the system, especially local-type-data caching and
metadata-path resolution. It took a few design revisions to get both
DynamicMetadataRequest and MetadataResponse to a shape that felt
right and seemed to make everything easier.
The design is laid out pretty clearly (I hope) in the comments on
DynamicMetadataRequest and MetadataResponse, so I'm not going to
belabor it again here. Instead, I'll list out the work that's still
outstanding:
- I'm sure there are places we're asking for complete metadata where
we could be asking for something weaker.
- I need to actually test the runtime behavior to verify that it's
breaking the cycles it's supposed to, instead of just not regressing
anything else.
- I need to add something to the runtime to actually force all the
generic arguments of a generic type to be complete before reporting
completion. I think we can get away with this for now because all
existing types construct themselves completely on the first request,
but there might be a race condition there if another asks for the
type argument, gets an abstract metadata, and constructs a type with
it without ever needing it to be completed.
- Non-generic resilient types need to be switched over to an IRGen
pattern that supports initialization suspension.
- We should probably space out the MetadataStates so that there's some
space between Abstract and Complete.
- The runtime just calmly sits there, never making progress and
permanently blocking any waiting threads, if you actually form an
unresolvable metadata dependency cycle. It is possible to set up such
a thing in a way that Sema can't diagnose, and we should detect it at
runtime. I've set up some infrastructure so that it should be
straightforward to diagnose this, but I haven't actually implemented
the diagnostic yet.
- It's not clear to me that swift_checkMetadataState is really cheap
enough that it doesn't make sense to use a cache for type-fulfilled
metadata in associated type access functions. Fortunately this is not
ABI-affecting, so we can evaluate it anytime.
- Type layout really seems like a lot of code now that we sometimes
need to call swift_checkMetadataState for generic arguments. Maybe
we can have the runtime do this by marking low bits or something, so
that a TypeLayoutRef is actually either (1) a TypeLayout, (2) a known
layout-complete metadata, or (3) a metadata of unknown state. We could
do that later with a flag, but we'll need to at least future-proof by
allowing the runtime functions to return a MetadataDependency.
- make @noescape function types trivial
- think_to_thick_function with @noescape result type
- Fix for getSwiftFunctionPointerCallee
Part of:
SR-5441
rdar://36116691
To make this stick, I've disallowed direct use of that overload of
CreateCall. I've left the Constant overloads available, but eventually
we might want to consider fixing those, too, just to get all of this
code out of the business of manually remembering to pass around
attributes and calling conventions.
The test changes reflect the fact that we weren't really setting
attributes consistently at all, in this case on value witnesses.
The code assumed if there is no context object but rather the captured argument
is reused as the context object that the parameter index for this argument is
going to be the last one. This is not true if there are empty types in the
parameter list.
rdar://33502272
The goals here are four-fold:
- provide cleaner internal abstractions
- avoid IR bloat from extra bitcasts
- avoid recomputing function-type lowering information
- allow more information to be propagated from the function
access site (e.g. class_method) to the call site
Use this framework immediately for class and protocol methods.
Use the KeyPath implementation's new support for instantiating and dealing with captures to lower the generic context required to dispatch computed accessors with dependent generics.
forwarding thunks
We omit passing some metatype parameters if they can be reconstructed from
regular arguments. However, the partial apply forwarder so far did not
reconstructing them from such arguments.
SR-4854
rdar://32134723
Replace `NameOfType foo = dyn_cast<NameOfType>(bar)` with DRY version `auto foo = dyn_cast<NameOfType>(bar)`.
The DRY auto version is by far the dominant form already used in the repo, so this PR merely brings the exceptional cases (redundant repetition form) in line with the dominant form (auto form).
See the [C++ Core Guidelines](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es11-use-auto-to-avoid-redundant-repetition-of-type-names) for a general discussion on why to use `auto` to avoid redundant repetition of type names.
We would run into an assertion during building the partial apply forwarding
thunk because we passed down a parameter convention of an empty argument
although we ignore it for the purpose of adding to the closure context.
However, the code path for the non-allocated closure context (0 or one capture)
would assert that there is only one convention.
Reconcile this by not adding the empty parameter to the convention array.
rdar://31487947
This was an unnecessary complication and didn't make a lot of
logical sense, because we can recover the witness table from
substitutions when we call a @convention(witness_method) anyway.
Also, to fix materializeForSet for generic subscripts, I want the
materializeForSet *callback* of a protocol witness to have
@convention(witness_method), which requires representing such
functions as a single function pointer in IRGen.
The hasPolymorphicParameters() method always returns true for a
SILFunctionType with witness_method calling convention, because
we have to pass the type metadata for 'Self'.
However, it is possible for a witness_method to have no generic
signature, if we're directly calling a concrete witness method
thunk, as can happen after devirtualization.
In this case, we would crash if the witness_method was partially
applied. Handle this case.
This fixes a regression from the recent cleanup to have IRGen use
SubstitutionMap: <https://github.com/apple/swift/pull/7211>
Use the generic type lowering algorithm described in
"docs/CallingConvention.rst#physical-lowering" to map from IRGen's explosion
type to the type expected by the ABI.
Change IRGen to use the swift calling convention (swiftcc) for native swift
functions.
Use the 'swiftself' attribute on self parameters and for closures contexts.
Use the 'swifterror' parameter for swift error parameters.
Change functions in the runtime that are called as native swift functions to use
the swift calling convention.
rdar://19978563
SubstitutionList is going to be a more compact representation of
a SubstitutionMap, suitable for inline allocation inside another
object.
For now, it's just a typedef for ArrayRef<Substitution>.
