The immediate desire is to minimize the set of ABI dependencies
on the layout of an ExecutorRef. In addition to that, however,
I wanted to generally reduce the code size impact of an unsafe
continuation since it now requires accessing thread-local state,
and I wanted resumption to not have to create unnecessary type
metadata for the value type just to do the initialization.
Therefore, I've introduced a swift_continuation_init function
which handles the default initialization of a continuation
and returns a reference to the current task. I've also moved
the initialization of the normal continuation result into the
caller (out of the runtime), and I've moved the resumption-side
cmpxchg into the runtime (and prior to the task being enqueued).
The current code generation will emit an autibsp after adjusting the
stack pointe for the tail call. If callee and caller argument area does
not match this would fail.
Most of the async runtime functions have been changed to not
expect the task and executor to be passed in. When knowing the
task and executor is necessary, there are runtime functions
available to recover them.
The biggest change I had to make to a runtime function signature
was to swift_task_switch, which has been altered to expect to be
passed the context and resumption function instead of requiring
the caller to park the task. This has the pleasant consequence
of allowing the implementation to very quickly turn around when
it recognizes that the current executor is satisfactory. It does
mean that on arm64e we have to sign the continuation function
pointer as an argument and then potentially resign it when
assigning into the task's resume slot.
rdar://70546948
The `coro.end.async` intrinsic allow specifying a function that is to be
tail-called as the last thing before returning.
LLVM lowering will inline the `must-tail-call` function argument to
`coro.end.async`. This `must-tail-call` function can contain a
`musttail` call.
```
define @my_must_tail_call_func(void (*)(i64) %fnptr, i64 %args) {
musttail call void %fnptr(i64 %args)
ret void
}
define @async_func() {
...
coro.end.async(..., @my_must_tail_call_func, %return_continuation, i64 %args)
unreachable
}
```
Create a TargetDispatchClassMetadata for Swift metadata that also has a dispatch-compatible vtable. Dispatch leaves room for ObjC class metadata so the two regions don't overlap. (The vtable currently consists of a single dummy entry; this will be filled out later.)
Rearrange the Job and AsyncTask hierarchy so that AsyncTask inherits only from Job, which in turn inherits from HeapObject. This gives all Job instances a dispatch-compatible isa field. It also gives them a refcount word, which is wasted on instances that aren't AsyncTask instances. Maybe we can find some use for that space in the future.
rdar://75227953
This is conditional on UseAsyncLowering and in the future should also be
conditional on `clangTargetInfo.isSwiftAsyncCCSupported()` once that
support is merged.
Update tests to work either with swiftcc or swifttailcc.
Foundation imports `free`, importing it as `dllimport dso_local` which
is not permitted. Clean up the IRGen to ensure that the two are not
emitted together.
In derivatives of loops, no longer allocate boxes for indirect case payloads. Instead, use a custom pullback context in the runtime which contains a bump-pointer allocator.
When a function contains a differentiated loop, the closure context is a `Builtin.NativeObject`, which contains a `swift::AutoDiffLinearMapContext` and a tail-allocated top-level linear map struct (which represents the linear map struct that was previously directly partial-applied into the pullback). In branching trace enums, the payloads of previously indirect cases will be allocated by `swift::AutoDiffLinearMapContext::allocate` and stored as a `Builtin.RawPointer`.
An AsyncFunctionPointer, defined in Task.h, is a struct consisting of
two i32s: (1) the relative address of the async function and (2) the
size of the async context to be allocated when calling that function.
Here, such structs are emitted for every async SILFunction that is
emitted.
`Builtin.createAsyncTask` takes flags, an optional parent task, and an
async/throwing function to execute, and passes it along to the
`swift_task_create_f` entry point to create a new (potentially child)
task, returning the new task and its initial context.
Add a new entry point for getting generic metadata which adds the
canonical metadata records attached to the nominal type descriptor to
the metadata cache.
Change the implementation of the primary entry-point
swift_getGenericMetadata to stop looking through canonical
prespecialized records.
Change the implementation of swift_getCanonicalSpecializedMetadata to
use the caching token attached to the nominal type descriptor to add
canonical prespecialized metadata records to the metadata cache only
once rather than using the cache variables to limit the number of times
the attempt was made.
The previous stage of bringup only had async functions taking a single
argument: the async context. The next stage will involve the task and
executor. Here, arguments are added for those values. To begin with,
null is always passed for these values.
several more places to use getOrCreateHelperFunction.
This means that several of these places are now emitting
shared functions rather than private ones, which I've
verified is okay. There are some other places where
privacy is still unfortunately necessary.
I've also fixed the name of the store-extra-inhabitants
helper function to say "store" instead of "get", which
is longstanding (but harmless because it's private).
Fixes rdar://66707994.
The new function swift_getCanonicalSpecializedMetadata takes a metadata
request, a prespecialized non-canonical metadata, and a cache as its
arguments. The idea of the function is either to bless the provided
prespecialized metadata as canonical if there is not currently a
canonical metadata record for the type it describes or else to return
the actual canonical metadata.
When called, the metadata cache checks for a preexisting entry for this
metadata. If none is found, the passed-in prespecialized metadata is
added to the cache. Otherwise, the metadata record found in the cache
is returned.
rdar://problem/56995359
This commit adds -lto flag for frontend to enable LTO at LLVM level.
When -lto=llvm given, compiler emits LLVM bitcode file instead of object
file and adds index summary for LTO.
In addition for ELF format, emit llvm.dependent-libraries section to
embed auto linking information
The new function swift_compareProtocolConformanceDescriptors calls
through to the preexisting code in MetadataCacheKey which has been
extracted out from MetadataCacheKey::compareWitnessTables into a new
public static function
MetadataCacheKey::compareProtocolConformanceDescriptors.
The new function's availability is "future" for now.
The new function `swift_compareTypeContextDescriptors` is equivalent to
a call through to swift::equalContexts. The implementation it the same
as that of swift::equalContexts with the following removals:
- Handling of context descriptors of kind other outside of
ContextDescriptorKind::Type_First...ContextDescriptorKind::Type_Last.
Because the arguments are both TypeContextDescriptors, the kinds are
known to fall within that range.
- Casting to TypeContextDescriptor. The arguments are already of that
type.
For now, the new function has "future" availability.
This commit adds -lto flag for driver to enable LTO at LLVM level.
When -lto=llvm given, compiler emits LLVM bitcode file instead of object
file and perform thin LTO using libLTO.dylib plugin.
When -lto=llvm-full given, perform full LTO instead of thin LTO.
Clang provides options to override that default value.
These options are accessible via the -Xcc flag.
Some Swift functions explicitly disable the frame pointer.
The clang options will not override those.
A lot of attributes are essentially default target configuration, and we should only differ when there's a good reason to.
For the attributes we were already setting:
- the ptrauth and target CPU/feature attributes are taken care of by Clang
- I've updated the optsize/minsize attributes to the apparent intent
- I've left the frame-pointer override in place for now
Fixes rdar://63289339, which was caused by Swift's ptrauth IR attributes getting out of sync with Clang's.
