To avoid crashing tools, we just propagate failure instead of
asserting. This makes debugging more difficult, though. When
this macro is enabled, messages are printed to standard error
to pinpoint the exact reason that type lowering bailed out.
The approach here is to split this into two cases:
- If all case payloads have a fixed size, spare bits may be
potentially used to differentiate between cases, and the
remote reflection library does not have enough information to
compute the layout itself.
However, the total size must be fixed, so IRGen just emits a
builtin type descriptor (which I need to rename to 'fixed type
descriptor' since these are also used for imported value types,
and now, certain enums).
- If at least one case has a size that depends on a generic
parameter or is a resilient type, IRGen does not know the size,
but this means fancy tricks with spare bits cannot be used either.
The remote reflection library uses the same approach as the
runtime, basically taking the maximum of the payload size and
alignment, and adding a tag byte.
As with single-payload enums, we produce a new kind of
RecordTypeInfo, this time with a field for every enum case.
All cases start at offset zero (but of course this might change,
if for example we put the enum tag before the address point).
Also, just as with single-payload enums, there is no remote
'project case index' operation on ReflectionContext yet.
So the the main benefit from this change is that we don't entirely
give up when doing layout of class instances containing enums;
however, tools still cannot look inside the enum values themselves,
except in the simplest cases involving optionals.
Notably, the remote reflection library finally understands all
of the standard library's collection types -- Array, Character,
Dictionary, Set, and String.
Attempt to lay out single-payload enums, using knowledge of extra
inhabitants where possible.
- The extra inhabitants of an aggregate are the extra inhabitants of
the first field. If the first field is empty, there are no extra
inhabitants, and subsequent fields do not affect anything.
- Function pointers and metatypes have different extra inhabitants
than Builtin.RawPointer, so have IRGen emit distinct builtin type
descriptors for those.
- Opaque existentials do not have extra inhabitants.
- Weak references do not have extra inhabitants.
Also, fix IRGen to emit more accurate enum reflection metadata in
these two cases:
- We now record whether enum cases are indirect or not. An indirect
case is the same as a payload case with Builtin.NativeObject.
- We now record whether a case is empty or not using the same logic
as the rest of IRGen. Previously, we would incorrectly emit a
payload type for a case with a payload that is an empty struct,
for example.
At this point we don't have a way to get the currently inhabited
enum case from a value. However, this is still an improvement because
we can still reflect other fields of aggregates containing enums,
instead of just giving up.
Finally make some methods on TypeCoverter private, and use 'friend'
to allow them to be accessed from other internal classes, making the
public API simpler.
As a first step to allowing the build script to build *only*
static library versions of the stdlib, change `add_swift_library`
such that callers must pass in `SHARED`, `STATIC`, or `OBJECT_LIBRARY`.
Ideally, only these flags would be used to determine whether to
build shared, static, or object libraries, but that is not currently
the case -- `add_swift_library` also checks whether the library
`IS_STDLIB` before performing certain additional actions. This will be
cleaned up in a future commit.
HOST_LIBRARY is supposed to mean "no matter what the defaults say, also build
this library for the host". FORCE_BUILD_FOR_HOST_SDK is a less confusing name.
@slava_pestov recently folded in @objc classes when building class field
descriptors - we just need to update the switch when considering records
for converting TypeRefs to TypeInfos.
rdar://problem/26594130
Previously we would emit both a builtin descriptor and field
descriptor for imported classes, but we only need the latter.
Untangle some code and fix a crash with imported Objective-C
generics in the process.
Fixes <rdar://problem/26498484>.
Although this is a target library, it does not need to link against
the standard library, because it doesn't have any Swift content in
it. We need to add a separate build flag for having CMake content
because saying a library "IS_STDLIB" isn't correct for this case.
rdar://problem/26399625
- Lower Objective-C class typerefs as strong references with unknown
reference counting.
- Lower other imported C types as builtin blobs of their known
size, alignment, etc.
In the future, it might be beneficial to track which stored properties
of imported types are pointers, for better conservative scanning of
outgoing pointers to the heap.
rdar://problem/26240258
rdar://problem/26240394
This adds various MetadataReader methods to support closure layout:
- Reading generic arguments from metadata
- Reading parent metadata
- Reading capture descriptor from heap metadata
To a large extent, this is not currently taken advantage of, because
SILGen always wraps address-only captures in SIL box types.
Tests are in the next patch.
Remote metadata for closure contexts points to a capture descriptor.
We have a local copy of all capture descriptors. Translate the
address by recording the local and remote start address of
reflection metadata.
Somehow ninja didn't rebuild everything, so I ended up pushing code
that didn't compile. I did a clean re-build and fixed a minor issue
in the logic, now the test passes.
When deriving substitutions from closure contexts, we end up with
a problem where we have an original type and a substituted type,
and the original type is not necessarily a type parameter.
We need to decompose the original and substituted types to derive
the substitutions that produced the substitution.
For example, deriveSubstitutions(Foo<T -> Int>, Foo<String -> Int>)
will give us a substitution of T := Int.
Closure context layout will depend on the instance itself as well
as the isa pointer, because instead of instantiating metadata for
closures that capture generic parameters, we store the substitutions
inside the context itself.
For classes, this entry point just reads the isa pointer, applies
the isa mask and proceeds down the metadata path.
For now, the only the latter is hooked up.
- Improper handling of read() returning an incomplete read
- Update SwiftReflectionTest library for new builtin types section
Only tested manually so far; automated tests coming soon.
We'd like to be able to compare TypeRefs with pointer equality,
but we can't link LLVMSupport, so make a lightweight TypeRefID
like FoldingSetID, that only supports the input types necessary
to unique TypeRefs.
rdar://problem/25924875
The thin vs thick distinction is handled a little awkwardly. Instead of
passing around abstraction patterns, we add a "must be thick" bit to
MetatypeTypeRef, and thicken substitutions (to handle T; T := C.Type)
and the result of a subtitution (to handle T.Type; T := C).
With the exception of enums this completes <rdar://problem/25738849>.
For now, just enough for lowering.
Perhaps we should have a way to always just get this information
from metadata instead, since protocol metadata is always static
and not instantiated.
This would require the static "object file" interface used by
swift-reflection-dump to take a callback for symbol lookup.
Also add slightly inaccurate lowering for the special case of an
optional of a reference type. I need to rethink the approach for
extra inhabitants and enums, but this suffices for now.
