Use a new mangling scheme that describes the layout of compound boxes. For compatibility with reflection-based clients, continue to use the legacy mangling for single-field boxes when emitting reflection TypeRefs until we fully support reflection for the new box implementation.
There were a few problems here with subclasses of Objective-C classes.
Use the InstanceStart field from rodata to correctly lay out instance
variables, and verify the results match with dynamic and static layout.
Better fix for <rdar://problem/27932061>.
If bad data is fed to the reader, it might be convinced it's looking at
a generic type. If the generic type parameter also happens to be the
same metadata pointer, an infinite recursion results. To prevent this,
insert an invalid type into the cache at the start of the read. If we
then ask for that same metadata pointer again, we'll return the
invalid/empty built type.
This also might improve performance a little by preventing rereading
and rebuilding types.
rdar://problem/26529650
Part 1: Generic SIL Boxes always have instatiated metadata with kind
HeapGenericLocalVariable, which includes a metadata pointer for the
boxed type.
Part 2, after this, is to provide some kind of outgoing pointer map for
fixed heap boxes, whose metadata may be shared among different but
destructor-compatible types.
rdar://problem/26240419
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.
Lowered function types appear in capture descriptors.
For now, we completely punt on demangling parameters and
results, and just hackishly map the SIL function type
representation to an AST function type representation.
This is good enough, because all we care about is whether
we have a raw function pointer, raw function pointer with
context, or a block.
Implement the ReflectionContext's implementation of:
swift_reflection_projectExistential.
First, we get the type info of the existential typeref - it should be a
record type info. If it's a class existential, it has trivial layout:
the first word is a pointer to the class instance. Otherwise, if the
value fits in the 3-word buffer of the existential container, it
trivially is also at the start of the container. Otherwise, the value is
off in a heap box somewhere, but the first word of the container is a
pointer to that box.
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.
Also, use the instance layout entry point in swift-reflection-test,
so that we can dump the layout of a class instance and not the
lowering of the reference value.
This tool should test the usage from SwiftRemoteMirror dylib and
the C API, since that is the public interface from which we're
vending the remote reflection functionality.
The metadata system doesn't actually unique based on labels
correctly, so the test case has to play some games. That's
something that will be easier to fix when there are fewer
clients poking at the internals of the metadata runtime.
Memory readers on the C-side of the API may actually have an object-
oriented design, so they may want to pass an instance to revive
when callbacks make it to the other side of the API boundary.
just the address. Use this to avoid repeatedly reading metadata so
often (even if it's cached, this is better). Fix some bugs involving
nominal type parents.
